530 Physik
Refine
Year of publication
Document Type
- Article (961) (remove)
Keywords
- diffusion (25)
- anomalous diffusion (22)
- gamma rays: general (20)
- ISM: supernova remnants (12)
- cosmic rays (12)
- stars: massive (11)
- organic solar cells (9)
- stars: atmospheres (9)
- astroparticle physics (8)
- perovskite solar cells (8)
- acceleration of particles (7)
- methods: numerical (7)
- stars: early-type (7)
- Magellanic Clouds (6)
- X-rays: binaries (6)
- galaxies: active (6)
- galaxies: evolution (6)
- galaxies: formation (6)
- radiation mechanisms: non-thermal (6)
- stochastic processes (6)
- turbulence (6)
- Residual stress (5)
- dynamics (5)
- fractional Brownian motion (5)
- galaxies: high-redshift (5)
- gamma rays: ISM (5)
- gamma rays: galaxies (5)
- intergalactic medium (5)
- stars: evolution (5)
- stars: neutron (5)
- Galaxy: halo (4)
- ISM: abundances (4)
- X-rays: stars (4)
- binaries: close (4)
- binaries: general (4)
- binaries: spectroscopic (4)
- catalogs (4)
- charge transport (4)
- chemotaxis (4)
- first-passage time (4)
- galaxies: star formation (4)
- instabilities (4)
- methods: data analysis (4)
- model (4)
- non-fullerene acceptors (4)
- organic photovoltaics (4)
- photochemistry (4)
- quasars: absorption lines (4)
- residual stress (4)
- stars: winds, outflows (4)
- subdwarfs (4)
- synchronization (4)
- techniques: imaging spectroscopy (4)
- techniques: spectroscopic (4)
- Aluminum alloys (3)
- Fokker-Planck equation (3)
- Galaxy: evolution (3)
- ISM: clouds (3)
- Langevin equation (3)
- Lasers (3)
- Levy walk (3)
- Neutron diffraction (3)
- Phonons (3)
- Solar cells (3)
- Ti-6Al-4V (3)
- X-ray (3)
- X-ray refraction (3)
- additive manufacturing (3)
- astrophysical plasmas (3)
- dark ages, reionization, first stars (3)
- density (3)
- dust (3)
- electrons (3)
- first passage time (3)
- first-passage (3)
- galaxies: interactions (3)
- galaxies: jets (3)
- gamma rays: stars (3)
- gamma-ray burst: general (3)
- geometric Brownian motion (3)
- hysteresis (3)
- magnetic fields (3)
- magnetosphere (3)
- methods: observational (3)
- networks (3)
- neutrinos (3)
- neutron diffraction (3)
- nonergodicity (3)
- photocurrent generation (3)
- photoluminescence (3)
- photovoltaics (3)
- polymer solar cells (3)
- pulsars: general (3)
- quasars: general (3)
- recombination (3)
- shock waves (3)
- solar wind (3)
- stars: Wolf-Rayet (3)
- stars: abundances (3)
- stochastic resetting (3)
- superstatistics (3)
- techniques: image processing (3)
- transport (3)
- 2D perovskites (2)
- 4 (2)
- ARPES (2)
- Additive manufacturing (2)
- Blocking (2)
- Boltzmann distribution (2)
- Bragg peak (2)
- Brownian motion (2)
- Comb model (2)
- Computed tomography (2)
- Crystal lattices (2)
- Curie transition (2)
- Doping (2)
- Dynamical systems (2)
- Electrical properties and parameters (2)
- Energy (2)
- Equilibrium-line altitudes (2)
- FLASH (2)
- Gaussian processes (2)
- Genetic programming (2)
- H II regions (2)
- Heterostructures (2)
- Hilbert transform (2)
- Holocene (2)
- Hysteresis (2)
- ISM (2)
- ISM: kinematics and dynamics (2)
- ISM: magnetic fields (2)
- ISM: structure (2)
- Kuramoto (2)
- Kuramoto model (2)
- LIBS (2)
- Levy flights (2)
- Levy walks (2)
- Löschkurve (2)
- MHD (2)
- Magnetism (2)
- Molecules (2)
- NAP-XPS (2)
- Network reconstruction (2)
- Nitrogen (2)
- Organic semiconductors (2)
- P(VDF-TrFE-CFE) terpolymer (2)
- Perovskites (2)
- Radiation belts (2)
- Raman spectroscopy (2)
- Resonanzenergietransfer (2)
- Schrodinger operators (2)
- Statistical and Nonlinear Physics (2)
- Sun: activity (2)
- Sun: chromosphere (2)
- Synchronization control (2)
- TIG-welding (2)
- Theorie von Förster (2)
- Thermal effects (2)
- Thin films (2)
- Ultrafast X-ray diffraction (2)
- Wechselwirkungsabstand (2)
- X-ray photoelectron spectroscopy (2)
- XPS (2)
- astronomical databases (2)
- behavior (2)
- biological physics (2)
- biological transport (2)
- bumps (2)
- charge generation (2)
- charge-transfer (2)
- climate (2)
- collective motion (2)
- comets: general (2)
- comets: individual: 67P/Churyumov-Gerasimenko (2)
- computed tomography (2)
- conductivity (2)
- control (2)
- convection (2)
- coupled rotators (2)
- creep (2)
- crystal structure (2)
- dielectric relaxation spectroscopy (2)
- diffusing diffusivity (2)
- dwarfs galaxies (2)
- electrostatic interactions (2)
- entanglement (2)
- first passage (2)
- first-hitting time (2)
- flexibility (2)
- galaxies (2)
- galaxies: ISM (2)
- galaxies: abundances (2)
- galaxies: haloes (2)
- galaxies: nuclei (2)
- galaxies: starburst (2)
- gamma-rays: galaxies (2)
- genomic DNA conformation (2)
- globular clusters: general (2)
- graphene (2)
- graphs (2)
- gravitational waves (2)
- group field theory (2)
- impact (2)
- infrared thermography (2)
- interaction distance (2)
- interface recombination (2)
- iron (2)
- memory effects (2)
- morphology (2)
- nanoparticles (2)
- neural networks (2)
- neutron (2)
- noise (2)
- noisy systems (2)
- non-Langevin recombination (2)
- nonfullerene acceptors (2)
- numerical relativity (2)
- oscillations (2)
- outflows (2)
- physics (2)
- planets and satellites: rings (2)
- plasma instabilities (2)
- plasmas (2)
- power spectral analysis (2)
- processing (2)
- professional knowledge (2)
- quantum field theory (2)
- quantum thermodynamics (2)
- quasi-Fermi level splitting (2)
- quenching curve (2)
- radiation belts (2)
- random diffusivity (2)
- relativistic processes (2)
- resonant energy transfer (2)
- scattering (2)
- selective laser melting (SLM) (2)
- solar cells (2)
- stars: AGB and post-AGB (2)
- stars: activity (2)
- stars: black holes (2)
- stars: chemically peculiar (2)
- stars: emission-line, Be (2)
- stars: fundamental parameters (2)
- stars: kinematics and dynamics (2)
- stars: low-mass (2)
- stars: magnetic field (2)
- stars: mass-loss (2)
- stars: rotation (2)
- stars: solar-type (2)
- stars: winds (2)
- statistical models (2)
- statistische Modelle (2)
- subdiffusion (2)
- submillimetre: ISM (2)
- sulfur (2)
- surface (2)
- surveys (2)
- synchronization transition (2)
- synchrotron X-ray diffraction (2)
- systems (2)
- theory of Förster (2)
- thermal (2)
- thermodynamics (2)
- thick junctions (2)
- time-series analysis (2)
- transient chaos (2)
- ultrafast dynamics (2)
- ultraviolet: ISM (2)
- voltage losses (2)
- waves (2)
- work function (2)
- (TSNMRS) (1)
- (high-)voltage measurements (1)
- (magnetohydrodynamics) MHD (1)
- 1,3,4-oxadiazole (1)
- 15 (1)
- 16 (1)
- 30S subunit (1)
- 3D printing (1)
- 3D tomography (1)
- AG (1)
- AI (1)
- APCI (1)
- ARTOF (1)
- Absorption (1)
- Accelerator mass spectrometry (1)
- Actin cytoskeleton dynamics (1)
- Adam-Delbruck scenario (1)
- Adaptation (1)
- Aggregate states (1)
- All-polymer heterojunctions (1)
- Alternating copolymers (1)
- Amazon rainforest (1)
- Ambipolar charge transport (1)
- Ambipolar materials (1)
- Anisotropy (1)
- Annealing (metallurgy) (1)
- Annealing treatment (1)
- Anomalous diffusion (1)
- Anomalous diffusion exponent (1)
- Anomalous transport (1)
- Answer Set Programming (1)
- Anthropocene (1)
- Approximation algorithms (1)
- Aqueous solution (1)
- Arabidopsis thaliana (1)
- Aromatic compounds (1)
- Array Seismology (1)
- Array design (1)
- Asia (1)
- Astroparticle physics (1)
- Astrophysics (1)
- Asymmetric warming (1)
- Atlantic Meridional Overturning Circulation (1)
- Atlantic meridional overturning circulation (1)
- Atomic force microscopy (1)
- Auger decay (1)
- Auger electron spectroscopy (1)
- Auger–Meitner (1)
- BESSY II (1)
- BL Lacertae objects: individual (1)
- BL Lacertae objects: individual (B2 1215+30, VER J1217+301) (1)
- BL Lacertae objects: individual (BL Lacertae = VER J2202+422) (1)
- BL Lacertae objects: individual (HESS J1943+213, VER J1943+213) (1)
- BL Lacertae objects: individual (Mrk 501) (1)
- BL Lacertae objects: individual (TXS 0506+056, VER J0509+057) (1)
- BL Lacertae objects: individual: Markarian 501 (1)
- Backbone modifications (1)
- Bayesian Model Averaging (1)
- Beam dynamics (1)
- Bessel functions (1)
- Beta-eucryptite (1)
- Big Data (1)
- Bilayer solar cells (1)
- Biological Physics (1)
- Biomimetic sensors (1)
- Black– Scholes model (1)
- Bloch-Torrey equation (1)
- Boolean model (1)
- Booster cavity (1)
- Boundary value problem (1)
- Breathing chimera states (1)
- Brownian motors (1)
- Brownian yet non-Gaussian diffusion (1)
- C-13 chemical shift (1)
- C60 (1)
- CDA (1)
- CH3NH3SnI3 (1)
- CMAS (1)
- COVID-19 (1)
- CRNS (1)
- CU (1)
- Caccioppoli inequality (1)
- Capacitance spectroscopy (1)
- Carrier dynamics (1)
- Cassini (1)
- Catalysis (1)
- Cations (1)
- Cattaneo equation (1)
- Ce/Zr (1)
- Cellular polypropylene (PP) (1)
- Central asia (1)
- Ceramics (1)
- Chaos synchronization (1)
- Charge separation (1)
- Charge-transfer state (1)
- Chebyshev inequality (1)
- Chorus waves (1)
- Chromosphere (1)
- Chromosphere, quiet (1)
- Climate modeling (1)
- Coherence-incoherence (1)
- Cohesive finite elements (1)
- Colorimetric analysis (1)
- Comb-lattice model (1)
- Comets (1)
- Comets composition (1)
- Comets nucleus (1)
- Communications/decision making (1)
- Complementarity (1)
- Complete asymptotics (1)
- Complexity theory (1)
- Computational chemistry (1)
- Concentrating solar power (CSP) (1)
- Conducting polymers (1)
- Conformational disorder (1)
- Continuum (1)
- Convolutional neural networks (1)
- Cosmogenic isotopes (1)
- Cosmogenic nuclides (1)
- Coster–Kronig (1)
- Coupled oscillators (1)
- Covalent interaction (1)
- Creep (1)
- Crystalline phases (1)
- Crystallization (1)
- CuI (1)
- Curie-transition (1)
- Cw electron beam (1)
- Cyclones (1)
- Cylindrical comb (1)
- DIC (1)
- DLR equations (1)
- DNA (1)
- DNA-PAINT (1)
- Damage (1)
- Data analysis (1)
- Data assimilation (1)
- Data-driven modelling (1)
- Debye screening (1)
- Deep learning (1)
- Defects (1)
- Dehnung (1)
- Deimos (1)
- Detergent (1)
- Dictyostelium (1)
- Dictyostelium discoideum (1)
- Dielectric hysteresis (1)
- Diffraction (1)
- Diffusion (1)
- Diffusion NMR (1)
- Diffusion coefficients (1)
- Dislocation motion (1)
- Disorder (1)
- Disperse dyes (1)
- Dispersion force (1)
- Distributed (1)
- DoS (1)
- Donor-Acceptor (DA) interface (1)
- Donor-acceptor copolymers (1)
- Doped semiconductors (1)
- Double-jet (1)
- Druck-Volumen-Änderung (1)
- Drude model (1)
- Dye transfer (1)
- Dynamic loading (1)
- Dynamical invariants (1)
- E-ring (1)
- E.coli (1)
- E7 (1)
- EMIC (1)
- Earth System trajectories (1)
- Econophysics (1)
- Edwards-Anderson order parameter (1)
- Electrets (1)
- Electric polarization (1)
- Electric potential (1)
- Electron back-scattered diffraction (1)
- Electron populations (1)
- Electron traps (1)
- Electronic noise (1)
- Electronic properties and materials (1)
- Electronics, photonics and device physics (1)
- Elektrostatische Wechselwirkung (1)
- Embedding (1)
- Emergency (1)
- Emergency response (1)
- Energetic disorder (1)
- Energy science and technology (1)
- Energy-level alignment (1)
- Epidemic spreading models (1)
- Epoxy resin (1)
- Epoxy resins (1)
- Equatorial ionosphere (1)
- Equilibrium (1)
- Essential spectrum (1)
- European storm-time model (1)
- Excited-state calculations; (1)
- Experimental techniques (1)
- Explainable AI (1)
- External quantum efficiency (1)
- Extreme events (1)
- Extreme precipitation (1)
- False negative (1)
- False positive (1)
- Fe2TiO5 (1)
- Femtosecond lasers (1)
- Fermi-level alignment (1)
- Fermi-level pinning (1)
- Field emission (1)
- Field experiments (1)
- Flashing ratchets (1)
- Flims (1)
- Fluorescence (1)
- Fokker– Planck equation (1)
- Forcemyography (1)
- Fortuin-Kasteleyn representation (1)
- Fox H-function (1)
- Fox H-functions (1)
- Fractal (1)
- Fractal dimension (1)
- Fractional Brownian motion (1)
- Frank-Condon analysis (1)
- Free-electron-laser science (1)
- Functional dependencies (1)
- Functional scaffolds (1)
- GEANT4 modeling (1)
- GMR sensors (1)
- Galaxies: high-redshift (1)
- Galaxies: interactions (1)
- Galaxy: center (1)
- Galaxy: general (1)
- Galaxy: structure (1)
- Gardner equation (1)
- Gas phase (1)
- Generalized Langevin equation (1)
- Geomagnetic secular variation (1)
- Gibbs point process (1)
- Ginzburg-Landau lattice (1)
- Glaciation (1)
- Glaciation Central Asia (1)
- Gold (1)
- Gold@polydopamine (1)
- Granite (1)
- Granulation (1)
- Gravitation (1)
- Green function (1)
- Green's function (1)
- Greenland (1)
- Green’ s functions (1)
- HALS (1)
- HRTEM (1)
- HTL (1)
- Haake-Lewenstein-Wilkens approach (1)
- Heat Transfer (1)
- Hermite polynomial expansion (1)
- Heterogeneous (1)
- Hexagonal grid (1)
- High specific surface area (1)
- Hodge theory (1)
- Hofmeister effect (1)
- Hong-Ou-Mandel effect (1)
- Hooke's law (1)
- Hybrid materials (1)
- Hydraulic models (1)
- Hydraulic networks (1)
- Hydrocarbons (1)
- Hydrodynamics (1)
- Hydrogels (1)
- Hydrogen activation (1)
- Hypernetwork (1)
- IACT (1)
- IMD (1)
- IMPTAM (1)
- IN718 (1)
- IR ellipsometry (1)
- IR spectroscopy (1)
- ISM : supernova remnants (1)
- ISM: general (1)
- ISM: individual objects (RX J1713.7-3946, G347.3-0.5) (1)
- ISM: jets and outflows (1)
- ISM: lines and bands (1)
- ISOS-L-1I protocol (1)
- IZO (1)
- Impurity segregation (1)
- In-situ (1)
- India (1)
- Inner magnetosphere (1)
- Instrumentation (1)
- Instrumentation and data management (1)
- Insulators (1)
- Interaction (1)
- Interdisciplinary Physics (1)
- Interface dipole (1)
- Interfaces (1)
- Interfacial strength (1)
- Interferometry (1)
- Interlayer (1)
- Intermittency (1)
- Internal stress (1)
- Interstellar medium (1)
- Intrachain order (1)
- Intragap states (1)
- Ir(111) (1)
- Irradiation (1)
- Junction model (1)
- Kalman filtering (1)
- Kelvin probe (1)
- Khalerchinskaya tundra (1)
- Kp index (1)
- LII (1)
- LLG equation (1)
- Laboratory astrophysics (1)
- Lakes (1)
- Land-sea thermal contrast (1)
- Laplace-type operator (1)
- Large deviation statistics (1)
- Laser powder bed fusion (1)
- Lattice dynamics (1)
- Lehrerbildung (1)
- Levy flight (1)
- Ligand-field state (1)
- Ligands (1)
- Localization regime (1)
- Localized chaos (1)
- Low carbon steel (1)
- Lysozyme (1)
- Längsschnittstudie (1)
- Lévy flights (1)
- Lévy walks (1)
- MATROSHKA-R (1)
- MO (1)
- Machine learning control (1)
- Magellanic Cloud (1)
- Magnetic field (1)
- Magnetic fields (1)
- Magnetic stray field (1)
- Magnetooptical effects (1)
- Markov additive processes (1)
- Mars (1)
- Maximum entropy method (1)
- Maximum likelihood estimation (1)
- Memory effects (1)
- Metal matrix composite (1)
- Metal oxides (1)
- Metals (1)
- Microcracked ceramics (1)
- Micromechanical modeling (1)
- Micromechanical schemes (1)
- Microscopic morphology (1)
- Microstructure (1)
- Microstructure and (1)
- Microstructure and texture (1)
- Mid-temperature transition (1)
- Mittag-Leffler function (1)
- Mittag-Leffler functions (1)
- MoS2 (1)
- Mobility imbalance (1)
- Mobility relaxation (1)
- Mode function (1)
- Model structural error (1)
- Molar water content (1)
- Molecular structure (1)
- Molecularly imprinted polymer (1)
- Monomers (1)
- Monte Carlo (1)
- Monte Carlo simulation (1)
- Moonlight (1)
- Motivation (1)
- Multi-dimensional Markovian embedding of non-Markovian dynamics (1)
- Multiphase composites (1)
- Multiple trapping model (1)
- NEXAFS (1)
- NLP (1)
- NTCM (1)
- NTF (1)
- Nanoparticles (1)
- Nanoreactor (1)
- Near-Field Optics (1)
- Network inference (1)
- Neumann problem (1)
- Neurooscillators (1)
- Ni (1)
- Nickel-based (1)
- Nickel-based superalloy (1)
- Node degree distribution (1)
- Noise floor (1)
- Non-Markovian processes (1)
- Non-linear dielectric spectroscopy (1)
- Non-perturbative analysis (1)
- Nonlinear analysis (1)
- Nonlinearity (1)
- Nonradiative recombination (1)
- Nuclear magnetic resonance spectroscopy (1)
- OFET (1)
- OSSS inequality (1)
- Observing methods (1)
- Oligomers (1)
- Open-circuit voltage (1)
- Optical resonators (1)
- Optoelectronic devices and components (1)
- Optoelectronic properties (1)
- Optoelectronics (1)
- Organic LEDs (1)
- Organic electronics (1)
- Organic thermoelectrics (1)
- Ornstein–Uhlenbeck process (1)
- Ott - Antonsen reduction (1)
- Ott-Antonsen equation (1)
- Ott-Antonsen reduction (1)
- Oxygen (1)
- P(VDF-TrFE-CFE) (1)
- PBLG (1)
- PEDOT (1)
- PEDOT:PSS (1)
- PNIPAm (1)
- Paleoclimate modeling (1)
- Parametric drift estimation (1)
- Pareto law (1)
- Partial synchrony (1)
- Partial wavelet coherence (1)
- Partially alternating copolymers (1)
- Performanztest (1)
- Periodic solutions (1)
- Perovskite solar cell (1)
- Perovskite solar cells (1)
- Phase dynamics (1)
- Phase modulation (1)
- Phase reconstruction (1)
- Phase transitions (1)
- Photo-CELIV (1)
- Photoconductivity (1)
- Photocurrent (1)
- Photoexcitations (1)
- Photon density wave spectroscopy (1)
- Photonic devices (1)
- Photosphere (1)
- Photothermal conversion (1)
- Photovoltaic gap (1)
- Physik (1)
- Pipe networks (1)
- Plasma Physics (1)
- Plasmonics (1)
- Plastibodies (1)
- Polarization (1)
- Polaron (1)
- Polycrystals (1)
- Polyetlioxysiloxane (1)
- Polymer intermixing (1)
- Probabilistic projections (1)
- Probability (1)
- Process analytical technology (1)
- Professionswissen (1)
- Prominences (1)
- Prominences, magnetic field (1)
- Prominences, quiescent (1)
- Proteins (1)
- Pseudo-Voigt fit function (1)
- Pulse induced transparency (1)
- PyTorch (1)
- Python (1)
- Quantum optics (1)
- Quartz (1)
- Quasimodes (1)
- Quiescent (1)
- Quiet (1)
- RF gun (1)
- RIXS (1)
- RIXS at FELs (1)
- Radiation dose calculation (1)
- Radiation on the ISS (1)
- Radiation protection (1)
- Raman imaging (1)
- Random cluster model (1)
- Random feature maps (1)
- Randomised tree algorithm (1)
- Rashba effect (1)
- Reaction mechanisms (1)
- Reactive adsorption (1)
- Reactive coupling (1)
- Recombination losses (1)
- Recurrence plots (1)
- Recurrence quantification analysis (1)
- Reflective writing (1)
- Reflexion (1)
- Reflexionsmodell (1)
- Reflexionsqualität (1)
- Reflexionstiefe (1)
- Relaxor-ferroelectric (RF) fluoropolymers (1)
- Relaxor-ferroelectric polymer (1)
- Residual stresses (1)
- Residue (1)
- Resolved and unresolved sources as a function of wavelength (1)
- Resonant inelastic X-ray scattering (1)
- Robin boundary condition (1)
- Rock (1)
- Rocks (1)
- RsgA (1)
- SCAPS-1D (1)
- SEM (1)
- SHPB (1)
- SIO₂ (1)
- SIR model (1)
- SLM (1)
- STM (1)
- Saddle Point (1)
- Saturn (1)
- Scaling exponents (1)
- Scan strategies (1)
- Scanning transmission electron microscopy (1)
- Scattering (1)
- Scattering breakdown (1)
- Schottky junction (1)
- Schrödinger equation (1)
- Science education (1)
- Seebeck coefficient (1)
- Seismicity modelling (1)
- Semantics (1)
- Shannon entropy (1)
- Shnol theorem (1)
- Shockley-Queisser model (1)
- Shockley-Read-Hall (1)
- Shocks (1)
- Si network disintegration (1)
- Signal processing (1)
- Silica source (1)
- Silicification (1)
- Silicon (1)
- Sinai diffusion (1)
- Skalarprodukt von Kraft und Weg (1)
- Small (1)
- Societal impacts (1)
- Solar Cycle, observations (1)
- Solar cycle (1)
- Solar energy (1)
- Solar energy and photovoltaic technology (1)
- Solvents (1)
- South-America (1)
- Space plasmas (1)
- Space radiation (1)
- Spectral diffusion (1)
- Spectral gap (1)
- Spectroscopy (1)
- Spin-echo (1)
- Stability (1)
- Stars: individual: 4U2206+54, BD+53 2790 (1)
- Statistical Physics (1)
- Statistical copolymers (1)
- Statistical inference (1)
- Steppest Descend method (1)
- Stern-Gerlach effect (1)
- Stille-type cross-coupling (1)
- Stimulated scattering (1)
- Stimuli-responsive materials (1)
- Stochastic reaction– diffusion (1)
- Strain hardening (1)
- Strain measurement (1)
- Stratosphere (1)
- Stress-strain relations (1)
- Structure-performance relationship (1)
- Structure-property relationships (1)
- Sub-gamma random variable (1)
- Subdiffusion (1)
- Sun (1)
- Sun: Chromosphere (1)
- Sun: corona (1)
- Sun: coronal mass ejections (CMEs) (1)
- Sun: filaments, prominences (1)
- Sun: flares (1)
- Sun: heliosphere (1)
- Sun: magnetic fields (1)
- Sun: photosphere (1)
- Supernova remnants (1)
- Surface properties (1)
- Surface treatment (1)
- Surfactant (1)
- Surfactants (1)
- TCOs (1)
- TD-DFT (1)
- TRMM (1)
- Teleconnection patterns (1)
- Tensile load (1)
- Tension (1)
- Terrestrial cosmogenic nuclide (1)
- Thermal Radiation (1)
- Thermal conductivity (1)
- Thermo optic effects (1)
- Thermoclectrics (1)
- Thermodynamic efficiency (1)
- Thermodynamic properties (1)
- Thiouracil (1)
- Time delay (1)
- Time series (1)
- Time-dependent mobility (1)
- Time-of-flight (TOF) (1)
- Topological matter (1)
- Transient photocurrent (1)
- Transition metals (1)
- Transition-metal ion (1)
- Trypanosoma cruzi (1)
- Tunneling (1)
- UV cross-linking (1)
- UV nanoimprint lithography (1)
- UV-VIS Spectroscopy (1)
- Ultra-high vacuum (1)
- Ultrafast X-rays (1)
- Ultraviolet photoelectron spectroscopy (1)
- University physics (1)
- Unterrichtsplanung (1)
- Uracil (1)
- V*V884 Sco (1)
- V-OC loss (1)
- VERB (1)
- VERB code (1)
- VERITAS (1)
- Vacuum fields (1)
- Vacuum-level alignment (1)
- Van Allen Probes (1)
- Vector bundle (1)
- Viscoelasticity (1)
- WAAM (1)
- WKB-expansion (1)
- Washing fastness (1)
- Water Vapor (1)
- Water distribution systems (1)
- Water-assisted crystallization (1)
- Wave Propagation (1)
- Wavelets (1)
- Wealth and income distribution (1)
- Weather regimes (1)
- X-ray absorption (1)
- X-ray absorption spectroscopy (1)
- X-ray and (1)
- X-ray computed (1)
- X-ray emission (1)
- X-ray optics (1)
- X-ray refraction; (1)
- X-ray scattering (1)
- X-ray spectroscopy (1)
- X-ray synchrotron diffraction (1)
- X-rays (1)
- X-rays : stars (1)
- X-rays: individuals: Circinus X-1 (1)
- X-rays: individuals: GRS 1915+105 (1)
- X-rays: individuals: V4641 Sgr (1)
- Yield strength (1)
- Zeolite synthesis (1)
- absorption (1)
- absorption lines (1)
- absorption measurements (1)
- acceleration (1)
- acceptance (1)
- acidic crosslinking (1)
- actin (1)
- actin waves (1)
- active matter (1)
- active particles (1)
- activity (1)
- actuators (1)
- adaptation and mitigation (1)
- additive (1)
- additive manufacturing (AM) (1)
- aerosol. photoacoustics (1)
- ageing (1)
- aggregation (1)
- air pollution (1)
- aluminium alloys (1)
- amphiphilic side chains (1)
- amplitude response (1)
- analysis (1)
- analytical model (1)
- analyzer-based imaging (1)
- anatomical connectivity (1)
- and governance (1)
- and surface diffusion (1)
- anomalous (1)
- anomalous (or non-Fickian) diffusion (1)
- anomalous heat conduction (1)
- antimicrobial peptides (1)
- antireflection (1)
- applications (1)
- approximate methods (1)
- aspect ratio (1)
- assembly factor (1)
- astronomy (1)
- astroparticle physic (1)
- asymmetric Levy flights (1)
- asymptotic analysis (1)
- asynchronous design (1)
- atmosphere (1)
- atomic force microscopy (AFM) (1)
- attosecond phenomena (1)
- authentication (1)
- authentication protocol (1)
- autocorrelation (1)
- autocorrelation function (1)
- autocorrelations (1)
- autoregressive models (1)
- axial next nearest neighbour Ising chains (1)
- azobenzene (1)
- azobenzene containing polymers (1)
- azobenzene containing surfactants (1)
- azobenzene-containing molecules (1)
- background (1)
- bacteria (1)
- bacterial swimming (1)
- bacterial swimming strategies (1)
- ball mill (1)
- bandgap (1)
- barrier escape (1)
- basis-sets (1)
- battery (1)
- battery-depletion attack (1)
- beam splitter (1)
- bifurcation analysis (1)
- binaries: eclipsing (1)
- binary neutron stars (1)
- biochemical oscillators (1)
- biohybrid microsystems (1)
- bioindicators (1)
- bioreceptors (1)
- biosensing (1)
- biosphere feedbacks (1)
- bismuth (1)
- bismuthene (1)
- black carbon (1)
- blade (1)
- block copolymer films (1)
- blue stragglers (1)
- boron-10 (1)
- boundary local time (1)
- brownian motion (1)
- brushes (1)
- bubbles (1)
- built-in potential (1)
- bulk (1)
- bulk heterojunction (1)
- bulk heterojunctions (1)
- bulk-heterojunction solar cells (1)
- cambridge cb4 0wf (1)
- cambs (1)
- cancer diagnosis (1)
- capacitance spectroscopy (1)
- carbene electron deficiency (1)
- carbenes (1)
- carbohydrate derivatives (1)
- cardiomyopathy (1)
- carrier density (1)
- cascading regime (1)
- cataclysmic variables (1)
- catalysis (1)
- catanionic vesicles (1)
- cell migration (1)
- cell motility (1)
- cell nucleus (1)
- cell polarity (1)
- cell-cell (1)
- cellular signalling (1)
- cesium lead halides (1)
- chains (1)
- channel (1)
- chaos (1)
- characterization (1)
- charge (1)
- charge carrier density (1)
- charge carrier extraction (1)
- charge collection (1)
- charge density (1)
- charge generation yield (1)
- charge injection across hybrid interfaces (1)
- charge recombination yield (1)
- charge repulsion (1)
- charge shielding (1)
- charge storage (1)
- charge transfers (1)
- charge transport layers (1)
- charge-carrier transport (1)
- charge-transfer states (1)
- chemical (1)
- chemical interface damping (1)
- chemical modification (1)
- chemical oxidative polymerization (1)
- chemomechanical coupling (1)
- chimera (1)
- chimera state (1)
- chimera states (1)
- chirality (1)
- chloroplast ribosome (1)
- chorus waves (1)
- chromosphere (1)
- circulation (1)
- circumstellar matter (1)
- classification (1)
- cleaner energy transitions (1)
- climate benefits (1)
- climate change (1)
- clustering (1)
- coarse-grained order parameter (1)
- code (1)
- codifference (1)
- coefficient (1)
- coefficients (1)
- cohomology (1)
- collective dynamics (1)
- colloidal particles (1)
- coloured (1)
- coloured and quantum noise (1)
- coma (1)
- comets (1)
- compacton (1)
- complementarity (1)
- complex (1)
- complex networks (1)
- complex systems (1)
- complexes (1)
- composites (1)
- configuration (1)
- confinement (1)
- conformation (1)
- conformational and hydrodynamic characteristics (1)
- conformational changes (1)
- conjugated polymers (1)
- consequences (1)
- conservation laws (1)
- conservative random walks (1)
- contact resistance (1)
- continuous distribution model (1)
- continuous symmetries (1)
- continuous time random (1)
- continuous time random walk (1)
- continuous time random walk (CTRW) (1)
- contraction (1)
- convolutional neural networks (1)
- cooperation (1)
- coordinate measurement machine (1)
- copper iodide (1)
- copper minerals (1)
- correlated noise (1)
- correlation functions (1)
- correlations (1)
- cortical network (1)
- costs (1)
- coupled initial boundary value problem (1)
- coupling (1)
- coupling function (1)
- covariance (1)
- craters (1)
- critical adsorption (1)
- critical avalanche dynamics (1)
- critical phenomena (1)
- cross layer chip (1)
- crossover anomalous diffusion dynamics (1)
- crossover dynamics (1)
- cryolithology (1)
- crystal (1)
- crystal growth (1)
- crystal orientation (1)
- crystalline (1)
- cyclic voltammetry (1)
- cylindrical geometry (1)
- damage (1)
- dark matter (1)
- dark matter detectors (1)
- dark matter experiments (1)
- dark matter theory (1)
- data analysis (1)
- data assimilation (1)
- data based NARMAX modeling (1)
- data behind figure (1)
- data cleansing (1)
- data profiling (1)
- databases (1)
- de Rham complex (1)
- decomposing anomalous diffusion (1)
- deep learning (1)
- defect detection (1)
- defects (1)
- delay differential equation (1)
- delay faults (1)
- delayed feedback (1)
- denial-of-service attack (1)
- density functional calculations (1)
- density functional theory (1)
- dependent velocity (1)
- dermis (1)
- design for Testability (1)
- detector (1)
- diamagnetic currents (1)
- dielectric (1)
- dielectric barrier discharges (1)
- dielectric hysteresis (1)
- dielectrics (1)
- differential scanning calorimetry (1)
- diffraction (1)
- diffraction enhanced imaging (1)
- diffraction-elastic constants (1)
- diffuse radiation (1)
- diffusion coefficients (1)
- diffusion exponent (1)
- diffusion-controlled reactions (1)
- diffusion-influenced (1)
- diffusion-wave equation (1)
- dimension independent bound (1)
- dimensional reduction (1)
- direction of optomechanical stress (1)
- director configuration (1)
- diselenide (1)
- dislocations (1)
- dispatchable renewable electricity (1)
- dispersion (1)
- dispersion force (1)
- doctor-blade coating (1)
- domain purity (1)
- domino effect (1)
- donor (1)
- donor-acceptor interfaces (1)
- doping (1)
- double-multilayer monochromators (1)
- doubly transient chaos (1)
- driven (1)
- driving force (1)
- droughts (1)
- dynamic light scattering (1)
- dynamic loading (1)
- dynamical cluster (1)
- dynamical systems (1)
- dynamics simulation (1)
- dynamo (1)
- early warning indicators (1)
- ecological (1)
- ecology and biodiversity (1)
- econophysics (1)
- ecosystems (1)
- efficiency (1)
- ejecta (1)
- electret polymers (1)
- electrets (1)
- electrical breakdown (1)
- electrical polarization hysteresis (1)
- electro-electrets (1)
- electro-fused zirconia (1)
- electro-modulation microscopy (1)
- electroanalysis (1)
- electrochemistry (1)
- electrokinetic phenomena (1)
- electromagnetic ion cyclotron waves (1)
- electromagnetic radiation (1)
- electron flux (1)
- electron flux forecasts (1)
- electron lifetimes (1)
- electron localization (1)
- electron microscopy (1)
- electron spectroscopy (1)
- electron-transfer (1)
- electrostatic (1)
- electrostatic interaction (1)
- electrostatics (1)
- elevated-temperature effects on the operation of dielectric-elastomer (1)
- ellipsometry (1)
- elongation (1)
- emic waves (1)
- emission factor (1)
- empirical modeling (1)
- empirical prediction (1)
- enacted PCK (1)
- energetic disorder (1)
- energetic disorders (1)
- energetic offset (1)
- energetic particle (1)
- energy (1)
- energy decarbonization (1)
- energy gradients (1)
- energy system modeling (1)
- energy-level alignments (1)
- england (1)
- ensemble and time averaged mean squared displacement (1)
- ensemble methods (1)
- entrance test (1)
- entropy production (1)
- epidermis (1)
- equation (1)
- equation approach (1)
- equation of state; (1)
- equatorial ionization anomaly (1)
- equatorial ionosphere (1)
- equatorial plasma bubbles (1)
- equatorial plasma depletions (1)
- ergodicity (1)
- exact results (1)
- excited-state proton-transfer (1)
- exciton dynamics (1)
- exciton plasmon coupling (1)
- excitonic materials (1)
- exclusion process (1)
- exclusion processes (1)
- expanding medium (1)
- expectation maximisation algorithm (1)
- experiments (1)
- exploit (1)
- external generation efficiency (1)
- external quantum efficiency (1)
- extremal values (1)
- extreme statistics (1)
- extrusion (1)
- fastest first-passage time of N walkers (1)
- femtosecond laser spectroscopy (1)
- ferro- and piezoelectrets (1)
- ferroelectric semiconductors (1)
- ferroelectricity and piezoelectricity in polymers (1)
- fiber-electrophoresis chip (1)
- field experience (1)
- field-effect transistor (1)
- figure of merit (1)
- fill factor (1)
- fill factor losses (1)
- film sensor (1)
- films (1)
- filter (1)
- financial time series (1)
- finite-size effects (1)
- first-arrival density (1)
- first-passage time distribution (1)
- first-passage times (1)
- first-reaction time (1)
- flagellum (1)
- flashover (1)
- flexible (1)
- flow network (1)
- fluorescence (1)
- fluorinated organic spacer (1)
- fluorination (1)
- fluoroethylenepropylene (FEP) copolymer (1)
- force methods (1)
- forcing from below (1)
- forecast (1)
- formal specification (1)
- formal verification (1)
- formation (1)
- fractal (1)
- fractal dimension (1)
- fractional diffusion (1)
- fractional dynamic equations (1)
- fractional dynamics (1)
- free-electron laser (1)
- friction (1)
- fullerenes (1)
- functional connectivity (1)
- functional materials (1)
- functionalization (1)
- fungus (1)
- galaxies: clusters: general (1)
- galaxies: elliptical and lenticular, cD (1)
- galaxies: individual (1)
- galaxies: individual: NGC 4038, NGC 4039 (1)
- galaxies: individual: Small Magellanic Cloud (1)
- galaxies: star clusters (1)
- galaxy evolution (1)
- gamma ray detectors (1)
- gamma rays: (1)
- gamma rays: diffuse (1)
- gamma rays: diffuse background (1)
- gamma-ray burst: individual (GRB 150323A) (1)
- gamma-ray bursts: general (1)
- gamma-rays: general (1)
- gas (1)
- gas chromatography (1)
- gene regulatory networks (1)
- general relativity (1)
- generalised langevin equation (1)
- generalized diffusion equation (1)
- generalized eigenfunction (1)
- generalized eigenfunctions (1)
- generational comparison (1)
- genetic networks (1)
- geomagnetic activity (1)
- geomagnetic observatory data (1)
- geomagnetic storm drivers (1)
- geomagnetic storms (1)
- geometrical deformations (1)
- geostationary orbit (1)
- glass (1)
- glassy systems (1)
- global surface warming (1)
- globular clusters: individual: NGC 2808 (1)
- globular clusters: individual: NGC 3201 (1)
- gold cluster (1)
- gold nanoflowers (1)
- gradient boosting (1)
- gradients (1)
- grafted polymers (1)
- granite (1)
- gravitation (1)
- gravitational lensing: strong (1)
- gravitational-wave astronomy (1)
- gravity (1)
- green solvents (1)
- greenhouse gas (1)
- ground state (1)
- group-subgroup relationships (1)
- guided self assembly (1)
- healing (1)
- heart failure (1)
- heat transfer (1)
- helium-3 alternative (1)
- heteroatoms (1)
- heterogeneous diffusion (1)
- heterogeneous diffusion process (1)
- heterogeneous ensemble of Brownian particles (1)
- heterogeneous media (1)
- heterojunction silicon solar cells (1)
- heterostructures (1)
- high dimensional (1)
- high impact polystyrene (1)
- high-frequency force (1)
- high-redshift (1)
- historical geomagnetic storms (1)
- history and philosophy of astronomy (1)
- hole (1)
- hole extraction (1)
- hole selective materials (1)
- hopping dynamics (1)
- human behaviour (1)
- humidity (1)
- hybrid manufacturing (1)
- hybrid material (1)
- hybrid metal oxides (1)
- hybrid nanoparticles (1)
- hybrid synthesis (1)
- hydration layer (1)
- hydrochemistry (1)
- hydrodynamic model (1)
- hydrogels (1)
- hydrogen bonds (1)
- hyperbolic attractor (1)
- ice harboring (1)
- image registration (1)
- imaging (1)
- impedance spectroscopy (1)
- implantable medical device (1)
- implants (1)
- imprinted electrodes (1)
- in situ (1)
- in situ monitoring (1)
- incoherent light (1)
- incoherent radiation (1)
- individual (1)
- individual: CU Vir (1)
- inference (1)
- influence of weak magnetic fields on living systems (1)
- information (1)
- information theory (1)
- infrared: galaxies (1)
- infrared: general (1)
- infrared: planetary systems (1)
- infrared: stars (1)
- inorganic perovskites (1)
- instability (1)
- instructional (1)
- instructional explanation (1)
- instrumentation: adaptive optics (1)
- interactions (1)
- interface engineering (1)
- interfaces (1)
- intermittency (1)
- intermolecular force (1)
- intersystem crossing (1)
- inversion (1)
- ion beam (1)
- ion channels (1)
- ion mobility spectrometry (1)
- ion optics (1)
- ionic crosslinking (1)
- ionosphere (1)
- iron cyanides (1)
- irreversible volume-change (1)
- irreversible work share (1)
- jump detection (1)
- kinetic of cis-trans isomerization (1)
- laboratory x-ray diffraction (1)
- land use (1)
- large area devices (1)
- large deviation function (1)
- large-deviation statistic (1)
- large-scale structure of Universe (1)
- laser powder bed fusion (L-PBF) (1)
- laser powder bed fusion (LPBF) AlSi10Mg alloy (1)
- laser pulses (1)
- laser-based additive manufacturing (1)
- lattice gas (1)
- layer-by-layer deposition (1)
- lead halide perovskite films (1)
- leakage scheme (1)
- lesson planning (1)
- light emission (1)
- light management (1)
- light photocontrol (1)
- linear stability analysis (1)
- linearized gravity (1)
- lipid bilayer membrane dynamics (1)
- living cells (1)
- local equilibrium (1)
- localisation (1)
- localization microscopy (1)
- longitudinal study (1)
- loss mechanisms (1)
- low (1)
- low donor content (1)
- low-frequency force (1)
- lunar exploration (1)
- machine learning (1)
- magnetic microstructures (1)
- magnetic nanoparticles (1)
- magnetic pressure (1)
- magnetic proximity effect (1)
- magnetic stray field (1)
- magnetisation (1)
- magnetostriction (1)
- manipulation (1)
- manufacturing (AM) (1)
- mass (1)
- master (1)
- material (1)
- matrix composites (1)
- maximum and range (1)
- maximum entropy analysis (1)
- mean residence time (1)
- mean versus most probable reaction times (1)
- mean-field model (1)
- mechanisms (1)
- melt-quench-anneal (1)
- membrane (1)
- membrane channel (1)
- memory and delay (1)
- memory kernel (1)
- mesoporous silicon (1)
- metal (1)
- metal halide perovskites (1)
- metal optics (1)
- metal species (1)
- methane localization (1)
- methods (1)
- methods: Data analysis (1)
- methods: MHD (1)
- methods: Observational (1)
- methods: statistical (1)
- micro computed tomography (XCT) (1)
- microcracking (1)
- microfluidic paper analytic device (mu PAD) (1)
- microscopy (1)
- microstructure-property relations (1)
- microtransport and -assembly (1)
- mid-temperature transition(s) (1)
- milton rd (1)
- minerals (1)
- miscellaneous (1)
- mixed boundary conditions (1)
- mixed domains (1)
- mobile ions (1)
- mobile-immobile model (1)
- mobility (1)
- modeling (1)
- modelling (1)
- models (1)
- modified electrode (1)
- modular logic programs (1)
- mold (1)
- molecular bottle brushes (1)
- molecular brushes (1)
- molecular conformation (1)
- molecular crystals (1)
- molecular hydrodynamics and (1)
- molecular overcrowding (1)
- molecular weight (1)
- molecules (1)
- monitoring (1)
- monolayer (1)
- monsoon (1)
- monte-carlo (1)
- motion registration (1)
- movement data (1)
- multi-messenger astrophysics (1)
- multichannel (1)
- multidimensional fractional diffusion equation (1)
- multiple (1)
- myosin II (1)
- nanocomposite (1)
- nanofiber (1)
- nanoscale energy transports (1)
- nanoscale heat transfer (1)
- nanoscale modeling (1)
- narrow escape problem (1)
- natriuretic peptide system (1)
- natural resources (biological and non-biological) (1)
- near-ambient pressure X-ray photoelectron spectroscopy (1)
- near-ambient pressure x-ray photoelectron spectroscopy (1)
- nebulae: general (1)
- negative thermal expansion (1)
- nematic liquid crystal (1)
- network dynamics (1)
- neural (1)
- neuronal networks (1)
- neutron powder diffraction (1)
- neutron resonance spin-echo spectroscopy (1)
- neutron spin-echo (1)
- neutron stars (1)
- neutrophils (1)
- nitride materials (1)
- nitrogen (1)
- non-Gaussian (1)
- non-Gaussian diffusion (1)
- non-Gaussian distribution (1)
- non-Gaussian probability (1)
- non-Gaussianity (1)
- non-Langevin reduction factors (1)
- non-contact heat transfer (1)
- non-destructive evaluation (1)
- non-equilibrium (1)
- non-equilibrium steady state (1)
- non-exponential relaxation (1)
- non-exponential statistics (1)
- non-extensive statistics (1)
- non-integer dimension (1)
- non-radiative recombination (1)
- non-repudiation (1)
- nonequilibrium physics (1)
- nonequilibrium stationary state (1)
- nonlinear (1)
- nonlinear frequency conversion (1)
- nonlinear lattice (1)
- nonlocal coupled oscillators (1)
- nonlocal coupling (1)
- nonradiative voltage losses (1)
- nonstationary diffusivity (1)
- novae (1)
- nucleobase (1)
- nucleobases (1)
- nucleus-independent chemical shifts (NICS) (1)
- numerical simulations (1)
- ocean heat uptake (1)
- on-farm evaluation (1)
- onshore wind (1)
- opacity (1)
- open quantum systems (1)
- open-circuit voltage (1)
- optical irradiation intensity (1)
- optical manipulation (1)
- optical simulations (1)
- optical spectroscopy (1)
- optical tomography (1)
- optics (1)
- option pricing (1)
- optoplasmonic (1)
- organic (1)
- organic field-effect transistors (1)
- organic interfaces (1)
- organic semiconductors; (1)
- organic solar cell (1)
- organohalide lead perovskites (1)
- orientation approaches (1)
- origins (1)
- osmotic flow (1)
- osmotic-pressure (1)
- overdamped brownian systems (1)
- oxidation state (1)
- oxygen (1)
- oxygen plasma (1)
- p-type (1)
- parameter (1)
- parameter inference (1)
- part I (1)
- particle morphology (1)
- passivation (1)
- patterning glass microfiber (1)
- patterns (1)
- peptides (1)
- percolation (1)
- percolation threshold (1)
- performance assessment (1)
- period doubling (1)
- periodically poled material (1)
- perovskite semiconductors (1)
- perovskite solar cell (1)
- perovskites (1)
- persistence (1)
- perturbation approach (1)
- phase approximation (1)
- phase behavior (1)
- phase diffusion (1)
- phase field model (1)
- phase oscillators (1)
- phase purity (1)
- phase response (1)
- phase response curve (1)
- phase transition (1)
- phase transitions (1)
- phase-isostable reduction (1)
- phase-transition boundary (1)
- phospholipid membranes (1)
- photocontrol (1)
- photodissociation region (PDR) (1)
- photoelectron (1)
- photoelectron spectroscopy (1)
- photoexcited hole transfer (1)
- photofragmentation (1)
- photoisomerization (1)
- photoluminescence quenching (1)
- photon recycling (1)
- photon statistics (1)
- photonic crystal fibers (1)
- photosensitive polymers (1)
- photosensitive surfactants (1)
- photostability (1)
- photovoltaic devices (1)
- physical chemistry (1)
- physical hydrogels (1)
- physics education (1)
- picosecond ultrasonics (1)
- piezoelectret (1)
- piezoelectrets (1)
- pink beams (1)
- pitch angle (1)
- pitch angle scattering (1)
- planetary (1)
- planetary nebulae: individual: SwSt1 (1)
- planets and satellites: dynamical evolution and stability (1)
- planets and satellites: individual (Saturn) (1)
- planning constraints (1)
- plasma flows (1)
- plasma pressure (1)
- plasmaspheric hiss (1)
- plasmaspheric plume (1)
- plasmonic chemistry (1)
- plasmonics (1)
- polarization (1)
- policies (1)
- politics (1)
- poly(gamma-benzyl L-glutamate) (1)
- poly(vinylidenefluoride-trifluoroethylene) P(VDF-TrFE) (1)
- polyelectrolyte adsorption (1)
- polyelectrolytes (1)
- polymer (1)
- polymer ferroelectrets (1)
- polymer-foam films (1)
- polymerase chain reaction (PCR) (1)
- polypropylene (1)
- polypyrrole (1)
- polysulfobetaines (1)
- polytetrafluoroethylene (PTFE) (1)
- polyurethanes (1)
- polyzwitterions (1)
- populations (1)
- pore orientation (1)
- porosity (1)
- porous carbon materials (1)
- porphyrin (1)
- positioning (1)
- positive solutions (1)
- posttranslational protein translocation (1)
- potential ene rgy surface (1)
- power conversion efficiency (1)
- power spectral density (1)
- power spectrum (1)
- pp-wave solutions (1)
- practicum (1)
- pre-service teachers (1)
- precipitation (1)
- prediction (1)
- preferred orientation (1)
- preparedness (1)
- pressure-volume change (1)
- pressures (1)
- printed electroacoustic thin-film transducers (1)
- printing (1)
- probabilistic inference (1)
- probability density function (1)
- process (1)
- process inference (1)
- process monitoring (1)
- projections (1)
- proteasome (1)
- protein folding (1)
- protein search (1)
- protein translocation (1)
- proteins (1)
- protocols (1)
- pulsars: individual: PSR B0656+14 (1)
- pulsars: individual: PSR B0833-45 (1)
- pulsars: individual: SXP 1062 (1)
- pulse compression (1)
- pulse front matching (1)
- pump-probe (1)
- purification (1)
- quality (1)
- quantum (1)
- quantum correlations (1)
- quantum gravity (1)
- quantum mechanics (1)
- quartz crystal microbalance (1)
- quasar: absorption line (1)
- quasars: (1)
- quasars: emission lines (1)
- quasars: individual: 3C 279 (1)
- quasars: individual: LBQS 0302-0018 (1)
- quasi-Fermi level (1)
- quasi-particles (1)
- quasi-steady-state photoinduced absorptions (1)
- radiation belt (1)
- radiation belt electrons (1)
- radiation belt forecasts (1)
- radiation pressure (1)
- radiative limit (1)
- radiative transfer (1)
- radio continuum: stars (1)
- rainy-season (1)
- random forest (1)
- random search processes (1)
- random walk (1)
- random-walk (1)
- random-walks (1)
- rare events (1)
- ratchets (1)
- reaction cascade (1)
- reaction-diffusion models (1)
- reactions (1)
- readout electronics (1)
- reanalysis (1)
- recombination losses (1)
- recombination order (1)
- recombinations (1)
- rectification (1)
- recurrence plot (1)
- reflected Brownian motion (1)
- reflecting boundary conditions (1)
- regional equity (1)
- regression (1)
- relationships (1)
- relative total electron content (1)
- relativistic electron precipitation (1)
- relaxor-ferroelectric polymer (1)
- relaxor-ferroelectric polymers (1)
- remote monitoring (1)
- repertory grid (1)
- research priorities (1)
- resetting (1)
- residual stress analysis (1)
- resolution matrix (1)
- resonant X-ray scattering (1)
- resonant inelastic X-ray scattering (1)
- resource assessments (1)
- reversible binding (1)
- reversible work share (1)
- reversible-share-theorem (1)
- ribosome assembly (1)
- right limits (1)
- ring (1)
- ring current (1)
- ring current electrons (1)
- ring current model (1)
- rock (1)
- rotation curves of galaxies (1)
- rotational diffusion (1)
- royal soc chemistry (1)
- run and tumble (1)
- rutile-type (1)
- scalability (1)
- scalar product of force and displacement (1)
- scaled Brownian motion (1)
- scanning tunneling microscopy (1)
- scanning tunneling spectroscopy (1)
- school internship (1)
- science park (1)
- screen (1)
- search dynamics (1)
- search efficiency (1)
- segmentations (1)
- selective contact (1)
- selective laser melting (1)
- self-organisation (1)
- self-sufficiency (1)
- self-sustained oscillations (1)
- sensors and actuators (1)
- seperation (1)
- sequence-controlled polymers (1)
- shell-like geometries (1)
- shifts (1)
- silicon (1)
- silver (1)
- single chain folding (1)
- single trajectories (1)
- single trajectory analysis (1)
- single-molecule (1)
- single-particle tracking (1)
- single-stranded-dna (1)
- single-trajectory analysis (1)
- sintering (1)
- skutterudite (1)
- small molecules (1)
- smart card (1)
- social acceptance (1)
- soft X-ray (1)
- soft X-ray absorption (1)
- soft X-ray beamline (1)
- soft X-ray spectroscopy (1)
- soft electro-active materials (1)
- soft matter (1)
- soil moisture (1)
- solar coronal mass ejections (1)
- solar storm (1)
- solid-state nanopores (1)
- solitary wave (1)
- soliton (1)
- solvation (1)
- solvent vapor annealing (1)
- space charge (1)
- space-charge effects (1)
- space-charge stability (1)
- space-dependent diffusivity (1)
- space-time fractional diffusion equation (1)
- spacing (1)
- spark plasma (1)
- spatial (1)
- spatial poisson distribution (1)
- specific ion effects (1)
- spectra (1)
- spectrometry (1)
- spectroscopic (1)
- spectroscopy (1)
- spin (1)
- spin foam models (1)
- spin glass (1)
- spin state (1)
- spin- and angle-resolved photoemission (1)
- spin-crossover (1)
- spin-dependent forces (1)
- spin-orbit coupling (1)
- spin-orbit interaction (1)
- spin-related factors (1)
- spin-resolved (1)
- spiro-OMeTAD (1)
- split Hopkinson pressure bar (1)
- splitting (1)
- spontaneous parametric down-conversion (1)
- spread F (1)
- sputtering (1)
- stability analysis (1)
- stability and accuracy (1)
- stable water isotopes (1)
- stars (1)
- stars : Wolf-Rayet (1)
- stars : atmospheres (1)
- stars : early-type (1)
- stars : evolution (1)
- stars : individual : xi Per (1)
- stars : individual : zeta Oph (1)
- stars : individual : zeta Ori (1)
- stars : individual : zeta Pup (1)
- stars : mass-loss (1)
- stars : winds, outflows (1)
- stars evolution (1)
- stars: Wolft-Rayet (1)
- stars: circumstellar matter (1)
- stars: early-typeP (1)
- stars: flare (1)
- stars: formation (1)
- stars: horizontal branch (1)
- stars: horizontal-branch (1)
- stars: individual (PHL 457, EQ Psc) (1)
- stars: individual: 4U1700-37 (1)
- stars: individual: DGCVn-gamma rays: stars (1)
- stars: individual: HD 137366 (1)
- stars: individual: HD 93129A (1)
- stars: individual: HR 5907 (1)
- stars: individual: PG 1610+062 (1)
- stars: individual: R 145 (1)
- stars: individual: SMC AB 6 (1)
- stars: individual: WR 7 (1)
- stars: late-type (1)
- stars: magnetars (1)
- stars: oscillations (1)
- stars: oscillations (including pulsations) (1)
- stars: variables: general (1)
- state space modelling (1)
- stationary stochastic process (1)
- statistical physics (1)
- statistically relevant volumes (1)
- statistics (1)
- stators (1)
- stellar content (1)
- stellar coronal mass ejections (1)
- stimuli-responsive structured polymer films (1)
- stochastic dynamics (1)
- stochastic models (1)
- stochastic process (1)
- stochastic resonance (1)
- stochastic thermodynamics (1)
- stochastic time series (1)
- stochastics (1)
- strain-free lattice (1)
- stress exponent (1)
- stress recovery (1)
- stress-relaxation (1)
- stroboscopic imaging (1)
- strong coupling (1)
- structure (1)
- structure of water (1)
- structure-property (1)
- structured environments (1)
- structured polynucleotides (1)
- structures (1)
- stuck-at faults (1)
- subgrain structure (1)
- summer (1)
- sunspots (1)
- superalloys (1)
- superdiffusion and (1)
- superluminescent diodes (1)
- supernovae: general (1)
- supervised machine learning (1)
- support vector machines (1)
- surface band bending (1)
- surface charge (1)
- surface cracks (1)
- surface modification (1)
- surface morphology (1)
- surface photovoltage (1)
- surface reactivity (1)
- surface recombination (1)
- surface reconstruction (1)
- surface states (1)
- surface tension (1)
- surface treatment (1)
- surface wetting (1)
- surface-enhanced Raman scattering (1)
- surface-enhanced infrared absorption spectroscopy (1)
- surface-roughened (1)
- susceptibility (1)
- synchrotron X-ray refraction (1)
- synchrotron X-ray refraction radiography (1)
- synchrotron X-ray refraction radiography (SXRR) (1)
- synchrotron radiation (1)
- synchrotron x-ray refraction radiography (SXRR) (1)
- synthesis (1)
- system-immanent forces (1)
- systemimmanente Kräfte (1)
- systems subjected to parameter drift (1)
- table-top sources (1)
- tandem solar cells (1)
- tau proteins (1)
- teacher education (1)
- techniques (1)
- techniques: Image processing (1)
- techniques: radial velocities (1)
- telegrapher's equation (1)
- telluride (1)
- tellurium (1)
- temperature (1)
- temperature dependence (1)
- terahertz range (1)
- ternary blends (1)
- texture (1)
- thermal barrier coatings (1)
- thermal conductivity (1)
- thermal energy storage (1)
- thermal expansion (1)
- thermal stimulation of (1)
- thermally enhanced actuators (1)
- thermally induced porosity (TIP) (1)
- thermally stimulated depolarization current (1)
- thermoactivational spectroscopy (1)
- thermodynamic control (1)
- thermodynamic length (1)
- thermoelectric materials (1)
- thermoelectric properties (1)
- thermoelectrics (1)
- theta neurons (1)
- thickness insensitive active layers (1)
- thin films (1)
- thin-film solar cells (1)
- thiouracil (1)
- thomas graham house (1)
- threshold voltages (1)
- through space NMR shieldings (1)
- time (1)
- time averaging (1)
- time series analysis (1)
- time-averaged mean squared displacement (1)
- time-fractional Schrödinger equation (1)
- time-resolved X-ray probing (1)
- time-resolved photoemission (1)
- timing resilient design (1)
- tipping cascade (1)
- tipping elements (1)
- tipping interactions (1)
- titanium dioxide (1)
- tomography (XCT) (1)
- topological community (1)
- total work (1)
- tracking (1)
- trade (1)
- tranfer excited-state (1)
- transfer dynamics (1)
- transient absorption spectroscopy (1)
- transient grating spectroscopy (1)
- transient spectroscopy (1)
- transmission (1)
- transparent conductors (1)
- transport layer (1)
- transport layers (1)
- transports (1)
- transversal instabilities (1)
- traveling waves (1)
- triple-axis spectroscopy (1)
- triple-cation perovskite (1)
- truncated power-law correlated noise (1)
- twisted state (1)
- ultrafast molecular dynamics (1)
- ultrafast optics (1)
- ultrafast phenomena (1)
- ultrafast photoacoustics (1)
- ultrafast spectroscopy (1)
- ultrafast x-ray diffraction (1)
- ultrarelativistic electrons (1)
- ultraviolet photoelectron spectroscopy (1)
- ultraviolet: galaxies (1)
- ultraviolet: stars (1)
- upconversion nanoparticles (1)
- utility-scale batteries (1)
- vacuum fields (1)
- van allen probes (RBSP) (1)
- van allen probes; (1)
- verb (1)
- verb simulations; (1)
- vibrational resonance (1)
- vibrational spectroscopy (1)
- viscoelastic effects and anomalous diffusion (1)
- viscosity (1)
- walks (1)
- water (1)
- water diffusion in the brain (1)
- water ice (1)
- water-interface (1)
- water-methane films (1)
- wave particle interaction (1)
- wave structure (1)
- wave-particle interactions (1)
- waveguides (1)
- weak ergodicity breaking (1)
- wearable (1)
- weather (1)
- weighted (1)
- whispering gallery modes (1)
- wurtzite type (1)
- x-ray free-electron lasers (1)
- x-ray photoemission (1)
- x-ray spectroscopies and phenomena (1)
- x-ray-absorption (1)
- zebrafish (1)
- zero-power defense (1)
- zwitterions (1)
- иперболический аттрактор (1)
- когомологии (1)
- комплекс де Рама (1)
- оллективная динамика (1)
- проблема Неймана (1)
- синхронизация (1)
- теория Ходжа (1)
Institute
- Institut für Physik und Astronomie (886)
- Institut für Chemie (36)
- Institut für Mathematik (15)
- Extern (8)
- Institut für Geowissenschaften (6)
- Institut für Umweltwissenschaften und Geographie (6)
- Mathematisch-Naturwissenschaftliche Fakultät (5)
- Fachgruppe Politik- & Verwaltungswissenschaft (3)
- Hasso-Plattner-Institut für Digital Engineering gGmbH (3)
- Institut für Biochemie und Biologie (3)
Chemotactic motion in a chemical gradient is an essential cellular function that controls many processes in the living world. For a better understanding and more detailed modelling of the underlying mechanisms of chemotaxis, quantitative investigations in controlled environments are needed. We developed a setup that allows us to separately address the dependencies of the chemotactic motion on the average background concentration and on the gradient steepness of the chemoattractant. In particular, both the background concentration and the gradient steepness can be kept constant at the position of the cell while it moves along in the gradient direction. This is achieved by generating a well-defined chemoattractant gradient using flow photolysis. In this approach, the chemoattractant is released by a light-induced reaction from a caged precursor in a microfluidic flow chamber upstream of the cell. The flow photolysis approach is combined with an automated real-time cell tracker that determines changes in the cell position and triggers movement of the microscope stage such that the cell motion is compensated and the cell remains at the same position in the gradient profile. The gradient profile can be either determined experimentally using a caged fluorescent dye or may be alternatively determined by numerical solutions of the corresponding physical model. To demonstrate the function of this adaptive microfluidic gradient generator, we compare the chemotactic motion of Dictyostelium discoideum cells in a static gradient and in a gradient that adapts to the position of the moving cell. Published by AIP Publishing.
Organic light-emitting transistors (OLETs) offer a huge potential for the design of highly integrated multifunctional optoelectronic systems and of intense nano scale light sources, such as the long-searched-for electrically pumped organic laser. In order to fulfill these promises, the efficiency and brightness of the current state-of-the-art devices have to be increased significantly. The dominating quenching process limiting the external quantum efficiency in OLETs is charge-exciton interaction. A comprehensive understanding of this quenching process is therefore of paramount importance. The present article reports a systematic investigation of charge-exciton interaction in organic transistors employing time resolved photoluminescence electro-modulation (PLEM) spectroscopy on the picosecond time scale. The results show that the injected charges reduce the exciton radiative recombination in two ways: (i) charges may prevent the generation of excitons and (ii) charges activate a further nonradiative channel for the exciton decay. Moreover, the transient PLEM measurements clearly reveal that not only trapped charges, as already reported in literature, but rather the entire injected charge density contributes to the quenching of the exciton population.
We study the hierarchical stellar structures in a similar to 1.5 deg(2) area covering the 30. Doradus-N158-N159-N160 starforming complex with the VISTA Survey of. Magellanic Clouds. Based on the young upper main-sequence stars, we find that the surface densities cover a wide range of values, from log(Sigma.pc(2))less than or similar to -2.0 to log(Sigma. pc(2)) greater than or similar to 0.0. Their distributions are highly non-uniform, showing groups that frequently have subgroups inside. The sizes of the stellar groups do not exhibit characteristic values, and range continuously from several parsecs to more than 100. pc; the cumulative size distribution can be well described by a single power law, with the power-law index indicating a projected fractal dimension D-2 = 1.6 +/- 0.3. We suggest that the phenomena revealed here support a scenario of hierarchical star formation. Comparisons with other star-forming regions and galaxies are also discussed.
The standard model for GRB afterglow emission treats the accelerated electron population as a simple power law, N(E) proportional to E-p for p greater than or similar to 2. However, in standard Fermi shock acceleration, a substantial fraction of the swept-up particles do not enter the acceleration process at all. Additionally, if acceleration is efficient, then the nonlinear back-reaction of accelerated particles on the shock structure modifies the shape of the nonthermal tail of the particle spectra. Both of these modifications to the standard synchrotron afterglow impact the luminosity, spectra, and temporal variation of the afterglow. To examine the effects of including thermal particles and nonlinear particle acceleration on afterglow emission, we follow a hydrodynamical model for an afterglow jet and simulate acceleration at numerous points during the evolution. When thermal particles are included, we find that the electron population is at no time well fitted by a single power law, though the highest-energy electrons are; if the acceleration is efficient, then the power-law region is even smaller. Our model predicts hard-soft-hard spectral evolution at X-ray energies, as well as an uncoupled X-ray and optical light curve. Additionally, we show that including emission from thermal particles has drastic effects (increases by factors of 100 and 30, respectively) on the observed flux at optical and GeV energies. This enhancement of GeV emission makes afterglow detections by future gamma-ray observatories, such as CTA, very likely.
What are the physical laws of the diffusive search of proteins for their specific binding sites on DNA in the presence of the macromolecular crowding in cells? We performed extensive computer simulations to elucidate the protein target search on DNA. The novel feature is the viscoelastic non-Brownian protein bulk diffusion recently observed experimentally. We examine the influence of the protein-DNA binding affinity and the anomalous diffusion exponent on the target search time. In all cases an optimal search time is found. The relative contribution of intermittent three-dimensional bulk diffusion and one-dimensional sliding of proteins along the DNA is quantified. Our results are discussed in the light of recent single molecule tracking experiments, aiming at a better understanding of the influence of anomalous kinetics of proteins on the facilitated diffusion mechanism.
Context:
Massive binaries play a crucial role in the Universe. Knowing the distributions of their orbital parameters is important for a wide range of topics from stellar feedback to binary evolution channels and from the distribution of supernova types to gravitational wave progenitors, yet no direct measurements exist outside the Milky Way.
Aims:
The Tarantula Massive Binary Monitoring project was designed to help fill this gap by obtaining multi-epoch radial velocity (RV) monitoring of 102 massive binaries in the 30 Doradus region.
Methods:
In this paper we analyze 32 FLAMES/GIRAFFE observations of 93 O- and 7 B-type binaries. We performed a Fourier analysis and obtained orbital solutions for 82 systems: 51 single-lined (SB1) and 31 double-lined (SB2) spectroscopic binaries.
Results:
Overall, the binary fraction and orbital properties across the 30 Doradus region are found to be similar to existing Galactic samples. This indicates that within these domains environmental effects are of second order in shaping the properties of massive binary systems. A small difference is found in the distribution of orbital periods, which is slightly flatter (in log space) in 30 Doradus than in the Galaxy, although this may be compatible within error estimates and differences in the fitting methodology. Also, orbital periods in 30 Doradus can be as short as 1.1 d, somewhat shorter than seen in Galactic samples. Equal mass binaries (q> 0.95) in 30 Doradus are all found outside NGC 2070, the central association that surrounds R136a, the very young and massive cluster at 30 Doradus’s core. Most of the differences, albeit small, are compatible with expectations from binary evolution. One outstanding exception, however, is the fact that earlier spectral types (O2–O7) tend to have shorter orbital periods than later spectral types (O9.2–O9.7).
Conclusions:
Our results point to a relative universality of the incidence rate of massive binaries and their orbital properties in the metallicity range from solar (Z⊙) to about half solar. This provides the first direct constraints on massive binary properties in massive star-forming galaxies at the Universe’s peak of star formation at redshifts z ~ 1 to 2 which are estimated to have Z ~ 0.5 Z⊙.
Statistical properties of a free-electron laser revealed by Hanbury Brown-Twiss interferometry
(2017)
We present a comprehensive experimental analysis of statistical properties of the self-amplified spontaneous emission free-electron laser (FEL) FLASH by means of Hanbury Brown and Twiss interferometry. The experiments were performed at FEL wavelengths of 5.5, 13.4, and 20.8 nm. We determined the second-order intensity correlation function for all wavelengths and different operation conditions of FLASH. In all experiments a high degree of spatial coherence (above 50%) was obtained. Our analysis performed in spatial and spectral domains provided us with the independent measurements of an average pulse duration of the FEL that were below 60 fs. To explain the complicated behavior of the second-order intensity correlation function we developed an advanced theoretical model that includes the presence of multiple beams and external positional jitter of the FEL pulses. By this analysis we determined that in one of the experiments external positional jitter was about 25% of the beam size. We envision that methods developed in our study will be used widely for analysis and diagnostics of FEL radiation.
We present rigorous results for the mean first passage time and first passage time statistics for two-channel Markov additive diffusion in a 3-dimensional spherical domain. Inspired by biophysical examples we assume that the particle can only recognise the target in one of the modes, which is shown to effect a non-trivial first passage behaviour. We also address the scenario of intermittent immobilisation. In both cases we prove that despite the perfectly non-recurrent motion of two-channel Markov additive diffusion in 3 dimensions the first passage statistics at long times do not display Poisson-like behaviour if none of the phases has a vanishing diffusion coefficient. This stands in stark contrast to the standard (one-channel) Markov diffusion counterpart. We also discuss the relevance of our results in the context of cellular signalling.
Can the statistical properties of single-electron transfer events be correctly predicted within a common equilibrium ensemble description? This fundamental in nanoworld question of ergodic behavior is scrutinized within a very basic semi-classical curve-crossing problem. It is shown that in the limit of non-adiabatic electron transfer (weak tunneling) well-described by the Marcus-Levich-Dogonadze (MLD) rate the answer is yes. However, in the limit of the so-called solvent-controlled adiabatic electron transfer, a profound breaking of ergodicity occurs. Namely, a common description based on the ensemble reduced density matrix with an initial equilibrium distribution of the reaction coordinate is not able to reproduce the statistics of single-trajectory events in this seemingly classical regime. For sufficiently large activation barriers, the ensemble survival probability in a state remains nearly exponential with the inverse rate given by the sum of the adiabatic curve crossing (Kramers) time and the inverse MLD rate. In contrast, near to the adiabatic regime, the single-electron survival probability is clearly non-exponential, even though it possesses an exponential tail which agrees well with the ensemble description. Initially, it is well described by a Mittag-Leffler distribution with a fractional rate. Paradoxically, the mean transfer time in this classical on the ensemble level regime is well described by the inverse of the nonadiabatic quantum tunneling rate on a single particle level. An analytical theory is developed which perfectly agrees with stochastic simulations and explains our findings.
We analyze the effects of covalent interactions in Ni 2p3d resonant inelastic X-ray scattering (RIXS) spectra from aqueous Ni2+ ions and find that the relative RIXS intensities of ligand-to-metal charge-transfer final states with respect to the ligand-field final states reflect the covalent mixing between Ni 3d and water orbitals. Specifically, the experimental intensity ratio at the Ni L-3-edge allows to determine that the Ni 3d orbitals have on average 5.5% of water character. We propose that 2p3d RIXS at the Ni L-3-edge can be utilized to quantify covalency in Ni complexes without the use of external references or simulations.
Atlantic Meridional Overturning Circulation (AMOC) projections are uncertain due to both model errors, as well as internal climate variability. An AMOC slowdown projected by many climate models is likely to have considerable effects on many aspects of global and North Atlantic climate. Previous studies to make probabilistic AMOC projections have broken new ground. However, they do not drift-correct or cross-validate the projections, and do not fully account for internal variability. Furthermore, they consider a limited subset of models, and ignore the skill of models at representing the temporal North Atlantic dynamics. We improve on previous work by applying Bayesian Model Averaging to weight 13 Coupled Model Intercomparison Project phase 5 models by their skill at modeling the AMOC strength, and its temporal dynamics, as approximated by the northern North-Atlantic temperature-based AMOC Index. We make drift-corrected projections accounting for structural model errors, and for the internal variability. Cross-validation experiments give approximately correct empirical coverage probabilities, which validates our method. Our results present more evidence that AMOC likely already started slowing down. While weighting considerably moderates and sharpens our projections, our results are at low end of previously published estimates. We project mean AMOC changes between periods 1960-1999 and 2060-2099 of -4.0 Sv and -6.8 Sv for RCP4.5 and RCP8.5 emissions scenarios respectively. The corresponding average 90% credible intervals for our weighted experiments are [-7.2, -1.2] and [-10.5, -3.7] Sv respectively for the two scenarios.
The Norwegian young sea ICE (N-ICE2015) expedition was designed to investigate the atmosphere-snow-ice-ocean interactions in the young and thin sea ice regime north of Svalbard. Radiosondes were launched twice daily during the expedition from January to June 2015. Here we use these upper air measurements to study the multiple cyclonic events observed during N-ICE2015 with respect to changes in the vertical thermodynamic structure, moisture content, and boundary layer characteristics. We provide statistics of temperature inversion characteristics, static stability, and boundary layer extent. During winter, when radiative cooling is most effective, we find the strongest impact of synoptic cyclones. Changes to thermodynamic characteristics of the boundary layer are associated with transitions between the radiatively "clear" and "opaque" atmospheric states. In spring, radiative fluxes warm the surface leading to lifted temperature inversions and a statically unstable boundary layer. Further, we compare the N-ICE2015 static stability distributions to corresponding profiles from ERA-Interim reanalysis, from the closest land station in the Arctic North Atlantic sector, Ny-Alesund, and to soundings from the SHEBA expedition (1997/1998). We find similar stability characteristics for N-ICE2015 and SHEBA throughout the troposphere, despite differences in location, sea ice thickness, and snow cover. For Ny-Alesund, we observe similar characteristics above 1000 m, while the topography and ice-free fjord surrounding Ny-Alesund generate great differences below. The long-term radiosonde record (1993-2014) from Ny-Alesund indicates that during the N-ICE2015 spring period, temperatures were close to the climatological mean, while the lowest 3000 m were 1-3 degrees C warmer than the climatology during winter. Plain Language Summary The Norwegian young sea ICE (N-ICE2015) expedition was designed to investigate the atmosphere-snow-ice-ocean interactions in the young and thin sea ice regime north of Svalbard. Radiosondes were launched twice daily during the expedition from January to June 2015. Here we use these upper air measurements to study the multiple cyclonic events observed during N-ICE2015 with respect to changes in the vertical thermodynamic structure, moisture content, and the atmospheric boundary layer characteristics. During winter, we find the strongest impact of synoptic cyclones, which transport warm and moist air into the cold and dry Arctic atmosphere. In spring, incoming solar radiation warms the surface. This leads to very different thermodynamic conditions and higher moisture content, which reduces the contrast between stormy and calm periods. Further, we compare the N-ICE2015 measurements to corresponding profiles from ERA-Interim reanalysis, from the closest land station in the Arctic North Atlantic sector, Ny-Alesund, and to soundings from the SHEBA expedition (1997/1998). We find similar stability characteristics for N-ICE2015 and SHEBA throughout the troposphere, despite differences in location, sea ice thickness, and snow cover. The comparisons highlight the value of the N-ICE2015 observation and show the importance of winter time observations in the Arctic North Atlantic sector.
This paper presents a new experimental method for the characterization of the surface damage caused by a heat shock on a Brazilian disk test sample. Prior to mechanical testing with a Hopkinson Split Pressure bar device, the samples were subjected to heat shock by placing a flame torch at a fixed distance from the sample’s surface for periods of 10, 30, and 60 s. The sample surfaces were studied before and after the heat shock using optical microscopy and profilometry, and the images were analyzed to quantify the damage caused by the heat shock. The complexity of the surface crack patterns was quantified using fractal dimension of the crack patterns, which were used to explain the results of the mechanical testing. Even though the heat shock also causes damage below the surface which cannot be quantified from the optical images, the presented surface crack pattern analysis can give a reasonable estimate on the drop rate of the tension strength of the rock.
We demonstrate plasmonically nano-engineered coherent random lasing and stimulated emission enhancement in a hybrid gainmedium of organic semiconductors doped with core-shell plasmonic nanoparticles. The gain medium is composed of a 300 +/- 2 nm thin waveguide of an organic semiconductor, doped with 53 nm gold nanoparticle cores, isolated within silica shells. Upon loading the nanoparticles, the threshold of amplified spontaneous emission is reduced from 1.75 mu J cm(-2) x 10(2) for an undoped gain medium, to 0.35 mu J cm(-2) x 10(2) for a highly concentrated gain medium, and lasing spikes narrower than 0.1 nm are obtained. Most importantly, selection of silica shells with thicknesses of 10, 17 and 21 nm enables engineering of the plasmon-exciton energy coupling and consequently tuning of the laser slope efficiency. With this approach, the slope efficiency is increased by two times by decreasing the silica shell from 21 nm down to 10 nm, due to the enhancement of the localized electric field.
Networks of coupled dynamical systems provide a powerful way to model systems with enormously complex dynamics, such as the human brain. Control of synchronization in such networked systems has far-reaching applications in many domains, including engineering and medicine. In this paper, we formulate the synchronization control in dynamical systems as an optimization problem and present a multi-objective genetic programming-based approach to infer optimal control functions that drive the system from a synchronized to a non-synchronized state and vice versa. The genetic programming-based controller allows learning optimal control functions in an interpretable symbolic form. The effectiveness of the proposed approach is demonstrated in controlling synchronization in coupled oscillator systems linked in networks of increasing order complexity, ranging from a simple coupled oscillator system to a hierarchical network of coupled oscillators. The results show that the proposed method can learn highly effective and interpretable control functions for such systems.
We discuss the notion of symmetries in non-local field theories characterized by integro-differential equations of motion, from a geometric perspective. We then focus on group field theory (GFT) models of quantum gravity and provide a general analysis of their continuous point symmetry transformations, including the generalized conservation laws following from them.
Bifurcations of dynamos in rotating and buoyancy-driven spherical Rayleigh-Benard convection in an electrically conducting fluid are investigated numerically. Both nonmagnetic and magnetic solution branches comprised of rotating waves are traced by path-following techniques, and their bifurcations and interconnections for different Ekman numbers are determined. In particular, the question of whether the dynamo branches bifurcate super- or sub-critically and whether a direct link to the primary pure convective states exists is answered.
Contactless pressure monitoring based on Forster resonance energy transfer between donor/acceptor pairs immobilized within elastomers is demonstrated. The donor/acceptor energy transfer is employed by dispersing terbium(III) tris[(2-hydroxybenzoyl)-2-aminoethyl] amine complex (LLC, donor) and CdSe/ZnS quantum dots (QD655, acceptor) in styrene-ethylene/buthylene-styrene (SEBS) and poly(dimethylsiloxane) (PDMS). The continuous monitoring of QD luminescence showed a reversible intensity change as the pressure signal is alternated between two stable states indicating a pressure sensitivity of 6350 cps kPa(-1). Time-resolved measurements show the pressure impact on the FRET signal due to an increase of decay time (270 ms up to 420 ms) for the donor signal and parallel drop of decay time (170 mu s to 155 mu s) for the acceptor signal as the net pressure applied. The LLC/QD655 sensors enable a contactless readout as well as space resolved monitoring to enable miniaturization towards smaller integrated stretchable opto-electronics. Elastic FRET sensors can potentially lead to developing profitable analysis systems capable to outdo conventional wired electronic systems (inductive, capacitive, ultrasonic and photoelectric sensors) especially for point-of-care diagnostics, biological monitoring required for wearable electronics.
Arctic Amplification of climate warming is caused by various feedback processes in the atmosphere-ocean-ice system and yields the strongest temperature increase during winter in the Arctic North Atlantic region. In our study, we attempt to quantify the advective contribution to the observed atmospheric warming in the Svalbard area. Based on radiosonde measurements from Ny-Ålesund, a strong dependence of the tropospheric temperature on the synoptic flow direction is revealed. Using FLEXTRA backward trajectories, an increase of advection from the lower latitude Atlantic region towards Ny-Ålesund is found that is attributed to a change in atmospheric circulation patterns. We find that about one-quarter (0.45 K per decade) of the observed atmospheric winter near surface warming trend in the North Atlantic region of the Arctic (2 K per decade) is due to increased advection of warm and moist air from the lower latitude Atlantic region, affecting the entire troposphere.
We study the degree of second-order coherence of the emission of a high-power multi-quantum well superluminescent diode with a lateral tapered amplifier section with and without optical feedback. When operated in an external cavity, the degree of second-order coherence changed from the almost thermal case of g((2))(0)approximate to 1.9 towards the mostly coherent case of g((2)) (0) approximate to 1.2 when the injection current at the tapered section was increased. We found good agreement with semi-classical laser theory near and below threshold while above laser threshold a slightly higher g((2))(0) was observed. As a free running device, the superluminescent diode yielded more than 400 mW of optical output power with good spatial beam quality of M-slow(2) < 1.6. In this case, the degree of second-order coherence dropped only slightly from 1.9 at low powers to 1.6 at the maximum output power. To our knowledge, this is the first investigation of a high-power tapered superluminescent diode concerning the degree of second-order coherence. Such a device might be useful for real-world applications probing the second order coherence function, such as ghost imaging.
In this study, we investigate the climatology of high-latitude total electron content (TEC) variations as observed by the dual-frequency Global Navigation Satellite Systems (GNSS) receivers onboard the Swarm satellite constellation. The distribution of TEC perturbations as a function of geographic/magnetic coordinates and seasons reasonably agrees with that of the Challenging Minisatellite Payload observations published earlier. Categorizing the high-latitude TEC perturbations according to line-of-sight directions between Swarm and GNSS satellites, we can deduce their morphology with respect to the geomagnetic field lines. In the Northern Hemisphere, the perturbation shapes are mostly aligned with the L shell surface, and this anisotropy is strongest in the nightside auroral (substorm) and subauroral regions and weakest in the central polar cap. The results are consistent with the well-known two-cell plasma convection pattern of the high-latitude ionosphere, which is approximately aligned with L shells at auroral regions and crossing different L shells for a significant part of the polar cap. In the Southern Hemisphere, the perturbation structures exhibit noticeable misalignment to the local L shells. Here the direction toward the Sun has an additional influence on the plasma structure, which we attribute to photoionization effects. The larger offset between geographic and geomagnetic poles in the south than in the north is responsible for the hemispheric difference.
Passive coherent combination of several discrete low power laser diodes is a promising way to overcome the issue of degrading beam quality when scaling single emitters to > 10W output power. Such systems would be an efficient alternative to current high power sources, yet they suffer from fatal coherence loss when operated well above threshold. We present a new way to obtain detailed coherence information for laser diode arrays using a spatial light modulator to help identify the underlying decoherence processes. Reconstruction tests of the emitted far-field distribution are conducted to evaluate the performance of our setup.
Over the last decades, the percentage of the age group choosing to pursue university studies has increased significantly across the world. At the same time, there are university teachers who believe that the standards have fallen. There is little research on whether students nowadays demonstrate knowledge or abilities similar to that of the preceding cohorts. However, in times of educational expansion, empirical evidence on student test performance is extremely helpful in evaluating how well educational systems cope with the increasing numbers of students. In this study, we compared a sample of 2322 physics freshmen from 2013 with another sample of 2718 physics freshmen from 1978 at universities in Germany with regard to their physics knowledge based on their results in the same entrance test. Previous results on mathematics knowledge and abilities in the same sample of students indicated that there was no severe decline in their average achievement. This paper compares the physics knowledge of the same two samples of students. Contrary to their mathematics results, their physics results showed a substantial decrease in physics knowledge as measured by the test.
In the present study, samples fabricated by varying the deposition hatch length during selective laser melting of nickel based superalloy Inconel 718 were investigated. Microstructure and texture of these samples was characterized using scanning electron microscopy, combined with electron back-scattered diffraction, and residual stress assessment, using neutron diffraction method. Textured columnar grains oriented along the sample building direction were observed in the shorter hatch length processed sample. A ten-fold increase in the hatch length reduced the texture intensity by a factor of two attributed to the formation of finer grains in the longer hatch length sample. Larger gradients of transverse residual stress in the longer hatch length sample were also observed. Along the build direction, compressive stresses in the shorter hatch length and negligible stresses for the longer hatch length specimen were observed. Changes to the temperature gradient (G) in response to the hatch length variation, influenced the G to growth rate (R) ratio and the product GxR, in agreement with the microstructures and textures formed. For the residual stress development, geometry of the part also played an important role. In summary, tailored isotropy could be induced in Inconel 718 by a careful selection of parameters during selective laser melting.
In order to investigate their microcracking behaviour, the microstructures of several beta-eucryptite ceramics, obtained from glass precursor and cerammed to yield different grain sizes and microcrack densities, were characterized by laboratory and synchrotron x-ray refraction and tomography. Results were compared with those obtained from scanning electron microscopy (SEM). In SEM images, the characterized materials appeared fully dense but computed tomography showed the presence of pore clusters. Uniaxial tensile testing was performed on specimens while strain maps were recorded and analyzed by Digital Image Correlation (DIC). X-ray refraction techniques were applied on specimens before and after tensile testing to measure the amount of the internal specific surface (i.e., area per unit volume). X-ray refraction revealed that (a) the small grain size (SGS) material contained a large specific surface, originating from the grain boundaries and the interfaces of TiO2 precipitates; (b) the medium (MGS) and large grain size (LGS) materials possessed higher amounts of specific surface compared to SGS material due to microcracks, which decreased after tensile loading; (c) the precursor glass had negligible internal surface. The unexpected decrease in the internal surface of MGS and LGS after tensile testing is explained by the presence of compressive regions in the DIC strain maps and further by theoretical arguments. It is suggested that while some microcracks merge via propagation, more close mechanically, thereby explaining the observed X-ray refraction results. The mechanisms proposed would allow the development of a strain hardening route in ceramics.
A constitutive model for the nonlinear or "pseudoplastic" mechanical behavior in a linear-elastic solid with thermally induced microcracks is developed and applied to experimental results. The model is termed strain dependent microcrack density approximation (SDMDA) and is an extension of the modified differential scheme that describes the slope of the stress-strain curves of microcracked solids. SDMDA allows a continuous variation in the microcrack density with tensile loading. Experimental uniaxial tensile response of beta-eucryptite glass and ceramics with controlled levels of microcracking is reported. It is demonstrated that SDMDA can well describe the extent of non-linearity in the experimental uniaxial tensile response of beta-eucryptite with varying levels of microcracking. The advantages of the SDMDA are discussed in regard to tensile loading.
A maximum entropy (MaxEnt) method is developed to predict flow rates or pressure gradients in hydraulic pipe networks without sufficient information to give a closed-form (deterministic) solution. This methodology substantially extends existing deterministic flow network analysis methods. It builds on the MaxEnt framework previously developed by the authors. This study uses a continuous relative entropy defined on a reduced parameter set, here based on the external flow rates. This formulation ensures consistency between different representations of the same network. The relative entropy is maximized subject to observable constraints on the mean values of a subset of flow rates or potential differences, the frictional properties of each pipe, and physical constraints arising from Kirchhoff’s first and second laws. The new method is demonstrated by application to a simple one-loop network and a 1,123-node, 1,140-pipe water distribution network in the suburb of Torrens, Australian Capital Territory, Australia.
We perform ab initio molecular dynamics simulations to study the femtosecond laser induced desorption of H-2, D-2, and HD from a H: D-saturated Ru(0001) surface. To this aim we have extended the ab initio molecular dynamics with electronic friction (AIMDEF) scheme to include a random force that is a function of a timedependent electronic temperature. The latter characterizes the action of the ultrashort laser pulse according to a two temperature model. This allows us to perform multidimensional, hot-electron driven reaction dynamics and investigate the dependence of the desorption yields on the relative H: D isotope concentration on the surface. Our AIMDEF simulations show that the desorption process takes place in the presence of a heated adsorbate system that clearly influences the desorption dynamics. The heating of the adsorbate system is more (less) pronounced the larger is the concentration of the lighter (heavier) isotope. As a result, we conclude that the presence of H on the surface favors the desorption of molecules, whereas the presence of D hampers it, in agreement with previous experimental observations in which the phenomenon of "dynamical promotion" of a surface reaction had been postulated.
Nanoscale Thermal Transfer
(2017)
Fixational eye movements show scaling behaviour of the positional mean-squared displacement with a characteristic transition from persistence to antipersistence for increasing time-lag. These statistical patterns were found to be mainly shaped by microsaccades (fast, small-amplitude movements). However, our re-analysis of fixational eye-movement data provides evidence that the slow component (physiological drift) of the eyes exhibits scaling behaviour of the mean-squared displacement that varies across human participants. These results suggest that drift is a correlated movement that interacts with microsaccades. Moreover, on the long time scale, the mean-squared displacement of the drift shows oscillations, which is also present in the displacement auto-correlation function. This finding lends support to the presence of time-delayed feedback in the control of drift movements. Based on an earlier non-linear delayed feedback model of fixational eye movements, we propose and discuss different versions of a new model that combines a self-avoiding walk with time delay. As a result, we identify a model that reproduces oscillatory correlation functions, the transition from persistence to antipersistence, and microsaccades.
Complementarity in single photon interference – the role of the mode function and vacuum fields
(2017)
Background
In earlier experiments the role of the vacuum fields could be demonstrated as the source of complementarity with respect to the temporal properties (Heuer et al., Phys. Rev. Lett. 114:053601, 2015).
Methods
Single photon first order interferences of spatially separated regions from the cone structure of spontaneous parametric down conversion allow for analyzing the role of the mode function in quantum optics regarding the complementarity principle.
Results
Here the spatial coherence properties of these vacuum fields are demonstrated as the physical reason for complementarity in these single photon quantum optical experiments. These results are directly connected to the mode picture in classical optics.
Conclusion
The properties of the involved vacuum fields selected via the measurement process are the physical background of the complementarity principle in quantum optics.
We introduce three strategies for the analysis of financial time series based on time averaged observables. These comprise the time averaged mean squared displacement (MSD) as well as the ageing and delay time methods for varying fractions of the financial time series. We explore these concepts via statistical analysis of historic time series for several Dow Jones Industrial indices for the period from the 1960s to 2015. Remarkably, we discover a simple universal law for the delay time averaged MSD. The observed features of the financial time series dynamics agree well with our analytical results for the time averaged measurables for geometric Brownian motion, underlying the famed Black–Scholes–Merton model. The concepts we promote here are shown to be useful for financial data analysis and enable one to unveil new universal features of stock market dynamics.
Molecules often fragment after photoionization in the gas phase. Usually, this process can only be investigated spectroscopically as long as there exists electron correlation between the photofragments. Important parameters, like their kinetic energy after separation, cannot be investigated. We are reporting on a femtosecond time-resolved Auger electron spectroscopy study concerning the photofragmentation dynamics of thymine. We observe the appearance of clearly distinguishable signatures from thymine′s neutral photofragment isocyanic acid. Furthermore, we observe a time-dependent shift of its spectrum, which we can attribute to the influence of the charged fragment on the Auger electron. This allows us to map our time-dependent dataset onto the fragmentation coordinate. The time dependence of the shift supports efficient transformation of the excess energy gained from photoionization into kinetic energy of the fragments. Our method is broadly applicable to the investigation of photofragmentation processes.
Anomalous diffusion is being discovered in a fast growing number of systems. The exact nature of this anomalous diffusion provides important information on the physical laws governing the studied system. One of the central properties analysed for finite particle motion time series is the intrinsic variability of the apparent diffusivity, typically quantified by the ergodicity breaking parameter EB. Here we demonstrate that frequently EB is insufficient to provide a meaningful measure for the observed variability of the data. Instead, important additional information is provided by the higher order moments entering by the skewness and kurtosis. We analyse these quantities for three popular anomalous diffusion models. In particular, we find that even for the Gaussian fractional Brownian motion a significant skewness in the results of physical measurements occurs and needs to be taken into account. Interestingly, the kurtosis and skewness may also provide sensitive estimates of the anomalous diffusion exponent underlying the data. We also derive a new result for the EB parameter of fractional Brownian motion valid for the whole range of the anomalous diffusion parameter. Our results are important for the analysis of anomalous diffusion but also provide new insights into the theory of anomalous stochastic processes.
While the performance of laboratory-scale organic solar cells (OSCs) continues to grow, development of high efficiency large area OSCs remains a big challenge. Although a few attempts to produce large area organic solar cells (OSCs) have been reported, there are still challenges on the way to realizing efficient module devices, such as the low compatibility of the thickness-sensitive active layer with large area coating techniques, the frequent need for toxic solvents and tedious optimization processes used during device fabrication. In this work, highly efficient thickness-insensitive OSCs based on PTB7-Th:PC71BM that processed with single-component green solvent 2-methylanisole are presented, in which both junction thickness limitation and solvent toxicity issues are simultaneously addressed. Careful investigation reveals that this green solvent prevents the evolution of PC71BM into large area clusters resulting in reduced charge carrier recombination, and largely eliminates trapping centers, and thus improves the thickness tolerance of the films. These findings enable us to address the scalability and solvent toxicity issues and to fabricate a 16 cm(2) OSC with doctor-blade coating with a state-of-the-art power conversion efficiency of 7.5% using green solvent.
We propose a method of reconstruction of the network coupling matrix for a basic voltage-model of the neural field dynamics. Assuming that the multivariate time series of observations from all nodes are available, we describe a technique to find coupling constants which is unbiased in the limit of long observations. Furthermore, the method is generalized for reconstruction of networks with time-delayed coupling, including the reconstruction of unknown time delays. The approach is compared with other recently proposed techniques.
We study synchronization properties of three nonlinearly coupled chaotic maps. Coupling is introduced in such a way, that it cannot be reduced to pairwise terms, but includes combined action of all interacting units. For two models of nonlinear coupling we characterize the transition to complete synchrony, as well as partially synchronized states. Relation to hypernetworks of chaotic units is also discussed.
We consider synchronization properties of arrays of spin-torque nano-oscillators coupled via an RC load. We show that while the fully synchronized state of identical oscillators may be locally stable in some parameter range, this synchrony is not globally attracting. Instead, regimes of different levels of compositional complexity are observed. These include chimera states (a part of the array forms a cluster while other units are desynchronized), clustered chimeras (several clusters plus desynchronized oscillators), cluster state (all oscillators form several clusters), and partial synchronization (no clusters but a nonvanishing mean field). Dynamically, these states are also complex, demonstrating irregular and close to quasiperiodic modulation. Remarkably, when heterogeneity of spin-torque oscillators is taken into account, dynamical complexity even increases: close to the onset of a macroscopic mean field, the dynamics of this field is rather irregular.
High-frequency (HF) deep brain stimulation (DBS) is the gold standard for the treatment of medically refractory movement disorders like Parkinson’s disease, essential tremor, and dystonia, with a significant potential for application to other neurological diseases. The standard setup of HF DBS utilizes an open-loop stimulation protocol, where a permanent HF electrical pulse train is administered to the brain target areas irrespectively of the ongoing neuronal dynamics. Recent experimental and clinical studies demonstrate that a closed-loop, adaptive DBS might be superior to the open-loop setup. We here combine the notion of the adaptive high-frequency stimulation approach, that aims at delivering stimulation adapted to the extent of appropriately detected biomarkers, with specifically desynchronizing stimulation protocols. To this end, we extend the delayed feedback stimulation methods, which are intrinsically closed-loop techniques and specifically designed to desynchronize abnormal neuronal synchronization, to pulsatile electrical brain stimulation. We show that permanent pulsatile high-frequency stimulation subjected to an amplitude modulation by linear or nonlinear delayed feedback methods can effectively and robustly desynchronize a STN-GPe network of model neurons and suggest this approach for desynchronizing closed-loop DBS.
In a recent paper [U. Lorenz and P. Saalfrank, Chem. Phys. 482, 69 (2017)], we proposed a robust scheme to set up a system-bath model Hamiltonian, describing the coupling of adsorbate vibrations (system) to surface phonons (bath), from first principles. The method is based on an embedded cluster approach, using orthogonal coordinates for system and bath modes, and an anharmonic phononic expansion of the system-bath interaction up to second order. In this contribution, we use this model Hamiltonian to calculate vibrational relaxation rates of H–Si and D–Si bending modes, coupled to a fully H(D)-covered Si(100)-(2×1) surface, at zero temperature. The D–Si bending mode has an anharmonic frequency lying inside the bath frequency spectrum, whereas the H–Si bending mode frequency is outside the bath Debye band. Therefore, in the present calculations, we only take into account one-phonon system-bath couplings for the D–Si system and both one- and two-phonon interaction terms in the case of H–Si. The computation of vibrational lifetimes is performed with two different approaches, namely, Fermi’s golden rule, and a generalized Bixon-Jortner model built in a restricted vibrational space of the adsorbate-surface zeroth-order Hamiltonian. For D–Si, the Bixon-Jortner Hamiltonian can be solved by exact diagonalization, serving as a benchmark, whereas for H–Si, an iterative scheme based on the recursive residue generation method is applied, with excellent convergence properties. We found that the lifetimes obtained with perturbation theory, albeit having almost the same order of magnitude—a few hundred fs for D–Si and a couple of ps for H–Si—, are strongly dependent on the discretized numerical representation of the bath spectral density. On the other hand, the Bixon-Jortner model is free of such numerical deficiencies, therefore providing better estimates of vibrational relaxation rates, at a very low computational cost. The results obtained with this model clearly show a net exponential decay of the time-dependent survival probability for the H–Si initial vibrational state, allowing an easy extraction of the bending mode “lifetime.” This is in contrast with the D–Si system, whose survival probability exhibits a non-monotonic decay, making it difficult to define such a lifetime. This different behavior of the vibrational decay is rationalized in terms of the power spectrum of the adsorbate-surface system. In the case of D–Si, it consists of several, non-uniformly distributed peaks around the bending mode frequency, whereas the H–Si spectrum exhibits a single Lorentzian lineshape, whose width corresponds to the calculated lifetime. The present work gives some insight into mechanisms of vibration-phonon coupling at surfaces. It also serves as a benchmark for multidimensional system-bath quantum dynamics, for comparison with approximate schemes such as reduced, open-system density matrix theory (where the bath is traced out and a Liouville-von Neumann equation is solved) or approximate wavefunction methods to solve the combined system-bath Schrödinger equation.
Effects of the target aspect ratio and intrinsic reactivity onto diffusive search in bounded domains
(2017)
Westudy the mean first passage time (MFPT) to a reaction event on a specific site in a cylindrical geometry—characteristic, for instance, for bacterial cells, with a concentric inner cylinder representing the nuclear region of the bacterial cell. Asimilar problem emerges in the description of a diffusive search by a transcription factor protein for a specific binding region on a single strand of DNA.We develop a unified theoretical approach to study the underlying boundary value problem which is based on a self-consistent approximation of the mixed boundary condition. Our approach permits us to derive explicit, novel, closed-form expressions for the MFPT valid for a generic setting with an arbitrary relation between the system parameters.Weanalyse this general result in the asymptotic limits appropriate for the above-mentioned biophysical problems. Our investigation reveals the crucial role of the target aspect ratio and of the intrinsic reactivity of the binding region, which were disregarded in previous studies. Theoretical predictions are confirmed by numerical simulations.
The influence of different parameters on the silicification procedure using lysozyme is reported. When polyethoxysiloxane (PEOS), an internally crosslinked silica reservoir, is used, regular structures with a narrow size distribution could be obtained only via introducing the silica precursor in two steps including initial dropping and subsequent addition of residual oil phase in one portion. We found that mixing sequence of mineralizing agents in the presence of a positively charged surfactant plays a key role in terms of silica precipitation when tetraethoxyorthosilicate (TEOS) is the oil phase. In contrast, well mineralized crumpled features with high specific surface area could be synthesized in the presence of PEOS as a silica precursor polymer, regardless of mixing sequence. Moreover, introducing sodium dodecyl sulfate (SDS) as a negatively charged surfactant resulted in regular silica sphere formation only in combination with hexylene glycol (MPD) as a specific co-solvent. Finally, it is demonstrated that by inclusion of different nanoparticles even more sophisticated hybrid materials can be generated.
The diffusion in the comb structures is a popular model of geometrically induced anomalous diffusion. In the present work we concentrate on the diffusion along the backbone in a system where sidebranches are planes, and the diffusion thereon is anomalous and described by continuous time random walks (CTRW). We show that the mean squared displacement (MSD) in the backbone of the comb behaves differently depending on whether the waiting time periods in the sidebranches are reset after the step in the backbone is done (a rejuvenating junction model), or not (a non-rejuvenating junction model). In the rejuvenating case the subdiffusion in the sidebranches only changes the prefactor in the ultra-slow (logarithmic) diffusion along the backbone, while in the non-rejuvenating case the ultraslow, logarithmic subdiffusion is changed to a much faster power-law subdiffusion (with a logarithmic correction) as it was found earlier by Iomin and Mendez [25]. Moreover, in the first case the result does not change if the diffusion in the backbone is itself anomalous, while in the second case it does. Two of the special cases of the considered models (the non-rejuvenating junction under normal diffusion in the backbone, and rejuvenating junction for the same waiting time distribution in the sidebranches and in junction points) were also investigated within the approach based on the corresponding generalized Fokker-Planck equations. (c) 2017 Elsevier Ltd. All rights reserved.
During muscle contractions, radial-force distributions are generated on muscle surfaces due to muscle-volume changes, from which the corresponding body motions can be recorded by means of so-called force myography (FMG). Piezo- or ferroelectrets are flexible piezoelectric materials with attractive materials and sensing properties. In addition to several other applications, they are suitable for detecting force variations by means of wearable devices. In this paper, we prepared piezoelectrets from cellular polypropylene films by optimizing the fabrication procedures, and developed an FMG-recording system based on piezoelectret sensors. Different hand and wrist movements were successfully detected on able-bodied subjects with the FMG system. The FMG patterns were evaluated and identified by means of linear discriminant analysis and artificial neural network algorithms, and average motion-classification accuracies of 96.1% and 94.8%, respectively, were obtained. This paper demonstrates the feasibility of using piezoelectret-film sensors for FMG and may thus lead to alternative methods for detecting body motion and to related applications, e.g., in biomedical engineering or structural-health monitoring.
The dynamics of fragmentation and vibration of molecular systems with a large number of coupled degrees of freedom are key aspects for understanding chemical reactivity and properties. Here we present a resonant inelastic X-ray scattering (RIXS) study to show how it is possible to break down such a complex multidimensional problem into elementary components. Local multimode nuclear wave packets created by X-ray excitation to different core-excited potential energy surfaces (PESs) will act as spatial gates to selectively probe the particular ground-state vibrational modes and, hence, the PES along these modes. We demonstrate this principle by combining ultra-high resolution RIXS measurements for gas-phase water with state-of-the-art simulations.
We report on light sensitive microgel particles that can change their volume reversibly in response to illumination with light of different wavelengths. To make the anionic microgels photosensitive we add surfactants with a positively charged polyamine head group and an azobenzene containing tail. Upon illumination, azobenzene undergoes a reversible photo-isomerization reaction from a trans- to a cis-state accompanied by a change in the hydrophobicity of the surfactant. Depending on the isomerization state, the surfactant molecules are either accommodated within the microgel (trans- state) resulting in its shrinkage or desorbed back into water (cis-isomer) letting the microgel swell. We have studied three surfactants differing in the number of amino groups, so that the number of charges of the surfactant head varies between 1 and 3. We have found experimentally and theoretically that the surfactant concentration needed for microgel compaction increases with decreasing number of charges of the head group. Utilization of polyamine azobenzene containing surfactants for the light triggered remote control of the microgel size opens up a possibility for applications of light responsive microgels as drug carriers in biology and medicine.
We report on a photo-assisted adsorption of gold nanoparticles on a silicon substrate studied using atomic-force microscopy and secondary ion mass-spectrometry. Depending on a silicon conductivity type (n-Si or p-Si), the amount of photo-assisted adsorbed gold nanoparticles either increases (n-Si) or decreases (p-Si) on irradiation. In addition, the impacts of a cationic polyelectrolyte monolayer and adsorption time were also revealed. The polyelectrolyte layer enhances the adsorption of the gold nanoparticles but decreases the influence of light. The results of the photo-assisted adsorption on two types of silicon wafer were explained by electron processes at the substrate/solution interface.
This work was supported by the German-Russian Interdisciplinary Science Center (G-RISC) funded by the German Federal Foreign Office via the German Academic Exchange Service (DAAD), Project No. P-2014b-1, and Russian foundation for basic research, Project No. 16-08-00524_a.
Bacteria swim in sequences of straight runs that are interrupted by turning events. They drive their swimming locomotion with the help of rotating helical flagella. Depending on the number of flagella and their arrangement across the cell body, different run-and-turn patterns can be observed. Here, we present fluorescence microscopy recordings showing that cells of the soil bacterium Pseudomonas putida that are decorated with a polar tuft of helical flagella, can alternate between two distinct swimming patterns. On the one hand, they can undergo a classical push-pull-push cycle that is well known from monopolarly flagellated bacteria but has not been reported for species with a polar bundle of multiple flagella. Alternatively, upon leaving the pulling mode, they can enter a third slow swimming phase, where they propel themselves with their helical bundle wrapped around the cell body. A theoretical estimate based on a random-walk model shows that the spreading of a population of swimmers is strongly enhanced when cycling through a sequence of pushing, pulling, and wrapped flagellar configurations as compared to the simple push-pull-push pattern.
Kuramoto and Battogtokh (2002 Nonlinear Phenom. Complex Syst. 5 380) discovered chimera states represented by stable coexisting synchrony and asynchrony domains in a lattice of coupled oscillators. After a reformulation in terms of a local order parameter, the problem can be reduced to partial differential equations. We find uniformly rotating, spatially periodic chimera patterns as solutions of a reversible ordinary differential equation, and demonstrate a plethora of such states. In the limit of neutral coupling they reduce to analytical solutions in the form of one-and two-point chimera patterns as well as localized chimera solitons. Patterns at weakly attracting coupling are characterized by virtue of a perturbative approach. Stability analysis reveals that only the simplest chimeras with one synchronous region are stable.
Chimera states consisting of synchronous and asynchronous domains in a medium of nonlinearly coupled phase oscillators have been considered. Stationary inhomogeneous solutions of the Ott-Antonsen equation for a complex order parameter that correspond to fundamental chimeras have been constructed. The direct numerical simulation has shown that these structures under certain conditions are transformed to oscillatory (breathing) chimera regimes because of the development of instability.
We investigate both analytically and by computer simulations the ensemble- and time-averaged, nonergodic, and aging properties of massive particles diffusing in a medium with a time dependent diffusivity. We call this stochastic diffusion process the (aging) underdamped scaled Brownian motion (UDSBM). We demonstrate how the mean squared displacement (MSD) and the time-averaged MSD of UDSBM are affected by the inertial term in the Langevin equation, both at short, intermediate, and even long diffusion times. In particular, we quantify the ballistic regime for the MSD and the time-averaged MSD as well as the spread of individual time-averaged MSD trajectories. One of the main effects we observe is that, both for the MSD and the time-averaged MSD, for superdiffusive UDSBM the ballistic regime is much shorter than for ordinary Brownian motion. In contrast, for subdiffusive UDSBM, the ballistic region extends to much longer diffusion times. Therefore, particular care needs to be taken under what conditions the overdamped limit indeed provides a correct description, even in the long time limit. We also analyze to what extent ergodicity in the Boltzmann-Khinchin sense in this nonstationary system is broken, both for subdiffusive and superdiffusive UDSBM. Finally, the limiting case of ultraslow UDSBM is considered, with a mixed logarithmic and power-law dependence of the ensemble-and time-averaged MSDs of the particles. In the limit of strong aging, remarkably, the ordinary UDSBM and the ultraslow UDSBM behave similarly in the short time ballistic limit. The approaches developed here open ways for considering other stochastic processes under physically important conditions when a finite particle mass and aging in the system cannot be neglected.
Identifying causal relations from observational data sets has posed great challenges in data-driven causality inference studies. One of the successful approaches to detect direct coupling in the information theory framework is transfer entropy. However, the core of entropy-based tools lies on the probability estimation of the underlying variables. Herewe propose a data-driven approach for causality inference that incorporates recurrence plot features into the framework of information theory. We define it as the recurrence measure of conditional dependence (RMCD), and we present some applications. The RMCD quantifies the causal dependence between two processes based on joint recurrence patterns between the past of the possible driver and present of the potentially driven, excepting the contribution of the contemporaneous past of the driven variable. Finally, it can unveil the time scale of the influence of the sea-surface temperature of the Pacific Ocean on the precipitation in the Amazonia during recent major droughts.
The SusKat-ABC (Sustainable Atmosphere for the Kathmandu Valley-Atmospheric Brown Clouds) international air pollution measurement campaign was carried out from December 2012 to June 2013 in the Kathmandu Valley and surrounding regions in Nepal. The Kathmandu Valley is a bowl-shaped basin with a severe air pollution problem. This paper reports measurements of two major greenhouse gases (GHGs), methane (CH4) and carbon dioxide (CO2), along with the pollutant CO, that began during the campaign and were extended for 1 year at the SusKat-ABC supersite in Bode, a semi-urban location in the Kathmandu Valley. Simultaneous measurements were also made during 2015 in Bode and a nearby rural site (Chanban) similar to 25 km (aerial distance) to the southwest of Bode on the other side of a tall ridge. The ambient mixing ratios of methane (CH4), carbon dioxide (CO2), water vapor, and carbon monoxide (CO) were measured with a cavity ring-down spectrometer (G2401; Picarro, USA) along with meteorological parameters for 1 year (March 2013-March 2014). These measurements are the first of their kind in the central Himalayan foothills. At Bode, the annual average mixing ratios of CO2 and CH4 were 419.3 (+/- 6.0) ppm and 2.192 (+/- 0.066) ppm, respectively. These values are higher than the levels observed at background sites such as Mauna Loa, USA (CO2: 396.8 +/- 2.0 ppm, CH4: 1.831 +/- 0.110 ppm) and Waliguan, China (CO2: 397.7 +/- 3.6 ppm, CH4: 1.879 +/- 0.009 ppm) during the same period and at other urban and semi-urban sites in the region, such as Ahmedabad and Shadnagar (India). They varied slightly across the seasons at Bode, with seasonal average CH4 mixing ratios of 2.157 (+/- 0.230) ppm in the pre-monsoon season, 2.199 (+/- 0.241) ppm in the monsoon, 2.210 (+/- 0.200) ppm in the post-monsoon, and 2.214 (+/- 0.209) ppm in the winter season. The average CO2 mixing ratios were 426.2 (+/- 25.5) ppm in the pre-monsoon, 413.5 (+/- 24.2) ppm in the monsoon, 417.3 (+/- 23.1) ppm in the postmonsoon, and 421.9 (+/- 20.3) ppm in the winter season. The maximum seasonal mean mixing ratio of CH4 in winter was only 0.057 ppm or 2.6% higher than the seasonal minimum during the pre-monsoon period, while CO2 was 12.8 ppm or 3.1% higher during the pre-monsoon period (seasonal maximum) than during the monsoon (seasonal minimum). On the other hand, the CO mixing ratio at Bode was 191% higher during the winter than during the monsoon season. The enhancement in CO2 mixing ratios during the pre-monsoon season is associated with additional CO2 emissions from forest fires and agro-residue burning in northern South Asia in addition to local emissions in the Kathmandu Valley. Published CO = CO2 ratios of different emission sources in Nepal and India were compared with the observed CO = CO2 ratios in this study. This comparison suggested that the major sources in the Kathmandu Valley were residential cooking and vehicle exhaust in all seasons except winter. In winter, brick kiln emissions were a major source. Simultaneous measurements in Bode and Chanban (15 July-3 October 2015) revealed that the mixing ratios of CO2, CH4, and CO were 3.8, 12, and 64% higher in Bode than Chanban. The Kathmandu Valley thus has significant emissions from local sources, which can also be attributed to its bowl-shaped geography that is conducive to pollution build-up. At Bode, all three gas species (CO2, CH4, and CO) showed strong diurnal patterns in their mixing ratios with a pronounced morning peak (ca. 08:00), a dip in the afternoon, and a gradual increase again through the night until the next morning. CH4 and CO at Chanban, however, did not show any noticeable diurnal variations. These measurements provide the first insights into the diurnal and seasonal variation in key greenhouse gases and air pollutants and their local and regional sources, which is important information for atmospheric research in the region.
Prospects for Cherenkov Telescope Array Observations of the Young Supernova Remnant RX J1713.7-3946
(2017)
We perform simulations for future Cherenkov Telescope Array (CTA) observations of RX J1713.7-3946, a young supernova remnant (SNR) and one of the brightest sources ever discovered in very high energy (VHE) gamma rays. Special attention is paid to exploring possible spatial (anti) correlations of gamma rays with emission at other wavelengths, in particular X-rays and CO/H I emission. We present a series of simulated images of RX J1713.7-3946 for CTA based on a set of observationally motivated models for the gamma-ray emission. In these models, VHE gamma rays produced by high-energy electrons are assumed to trace the nonthermal X-ray emission observed by XMM-Newton, whereas those originating from relativistic protons delineate the local gas distributions. The local atomic and molecular gas distributions are deduced by the NANTEN team from CO and H I observations. Our primary goal is to show how one can distinguish the emission mechanism(s) of the gamma rays (i.e., hadronic versus leptonic, or a mixture of the two) through information provided by their spatial distribution, spectra, and time variation. This work is the first attempt to quantitatively evaluate the capabilities of CTA to achieve various proposed scientific goals by observing this important cosmic particle accelerator.
Imaging atmospheric Cherenkov telescopes (IACTs) are equipped with sensitive photomultiplier tube (PMT) cameras. Exposure to high levels of background illumination degrades the efficiency of and potentially destroys these photo-detectors over time, so IACTs cannot be operated in the same configuration in the presence of bright moonlight as under dark skies. Since September 2012, observations have been carried out with the VERITAS IACTs under bright moonlight (defined as about three times the night-sky-background (NSB) of a dark extragalactic field, typically occurring when Moon illumination > 35%) in two observing modes, firstly by reducing the voltage applied to the PMTs and, secondly, with the addition of ultra-violet (UV) bandpass filters to the cameras. This has allowed observations at up to about 30 times previous NSB levels (around 80% Moon illumination), resulting in 30% more observing time between the two modes over the course of a year. These additional observations have already allowed for the detection of a flare from the 1ES 1727 + 502 and for an observing program targeting a measurement of the cosmic-ray positron fraction. We provide details of these new observing modes and their performance relative to the standard VERITAS observations. (C) 2017 Elsevier B.V. All rights reserved.
Strong events of long-range transported biomass burning aerosol were detected during July 2013 at three EARLINET (European Aerosol Research Lidar Network) stations, namely Granada (Spain), Leipzig (Germany) and Warsaw (Poland). Satellite observations from MODIS (Moderate Resolution Imaging Spectroradiometer) and CALIOP (Cloud-Aerosol Lidar with Orthogonal Polarization) instruments, as well as modeling tools such as HYSPLIT (Hybrid Single-Particle Lagrangian Integrated Trajectory) and NAAPS (Navy Aerosol Analysis and Prediction System), have been used to estimate the sources and transport paths of those North American forest fire smoke particles. A multiwavelength Raman lidar technique was applied to obtain vertically resolved particle optical properties, and further inversion of those properties with a regularization algorithm allowed for retrieving microphysical information on the studied particles. The results highlight the presence of smoke layers of 1-2 km thickness, located at about 5 km a.s.l. altitude over Granada and Leipzig and around 2.5 km a.s.l. at Warsaw. These layers were intense, as they accounted for more than 30% of the total AOD (aerosol optical depth) in all cases, and presented optical and microphysical features typical for different aging degrees: color ratio of lidar ratios (LR532/LR355) around 2, alpha-related angstrom exponents of less than 1, effective radii of 0.3 mu m and large values of single scattering albedos (SSA), nearly spectrally independent. The intensive microphysical properties were compared with columnar retrievals form co-located AERONET (Aerosol Robotic Network) stations. The intensity of the layers was also characterized in terms of particle volume concentration, and then an experimental relationship between this magnitude and the particle extinction coefficient was established.
In order to analyse the sensitivity of the equatorial ionospheric current system, i.e. the solar quiet current system and the equatorial electrojet, to solar cycle variations and to the secular variation of the geomagnetic main field, we have analysed 51 years (1935-1985) of geomagnetic observatory data from Huancayo, Peru. This period is ideal to analyse the influence of the main field strength on the amplitude of the quiet daily variation, since the main field decreases significantly from 1935 to 1985, while the distance of the magnetic equator to the observatory remains stable. To this end, we digitised some 19 years of hourly mean values of the horizontal component (H), which have not been available digitally at the World Data Centres. Then, the sensitivity of the amplitude Ali of the quiet daily variation to both solar cycle variations (in terms of sunspot numbers and solar flux F10.7) and changes of the geomagnetic main field strength (due to secular variation) was determined. We confirm an increase of Delta H for the decreasing main field in this period, as expected from physics based models (Cnossen, 2016), but with a somewhat smaller rate of 4.4% (5.8% considering one standard error) compared with 6.9% predicted by the physics based model.
Inorganic-organic perovskites like methylammonium-lead-iodide have proven to be an effective class of 17 materials for fabricating efficient solar cells. To improve their performance, light management techniques using textured surfaces, similar to those used in established solar cell technologies, should be considered. Here, we apply a light management foil created by UV nanoimprint lithography on the glass side of an inverted (p-i-n) perovskite solar cell with 16.3% efficiency. The obtained 1 mA cm(-2) increase in the short-circuit current density translates to a relative improvement in cell performance of 5%, which results in a power conversion efficiency of 17.1%. Optical 3D simulations based on experimentally obtained parameters were used to support the experimental findings. A good match between the simulated and experimental data was obtained, validating the model. Optical simulations reveal that the main improvement in device performance is due to a reduction in total reflection and that relative improvement in the short-circuit current density of up to 10% is possible for large-area devices. Therefore, our results present the potential of light management foils for improving the device performance of perovskite solar cells and pave the way for further use of optical simulations in the field of perovskite solar cells.
Absorption Tails of Donor
(2017)
In disordered organic semiconductors, the transfer of a rather localized charge carrier from one site to another triggers a deformation of the molecular structure quantified by the intramolecular relaxation energy. A similar structural relaxation occurs upon population of intermolecular charge-transfer (CT) states formed at organic electron donor (D)-acceptor (A) interfaces. Weak CT absorption bands for D A complexes occur at photon energies below the optical gaps of both the donors and the C-60 acceptor as a result of optical transitions from the neutral ground state to the ionic CT state. In this work, we show that temperature-activated intramolecular vibrations of the ground state play a major role in determining the line shape of such CT absorption bands. This allows us to extract values for the relaxation energy related to the geometry change from neutral to ionic CT complexes. Experimental values for the relaxation energies of 20 D:C-60 CT complexes correlate with values calculated within density functional theory. These results provide an experimental method for determining the polaron relaxation energy in solid-state organic D-A blends and show the importance of a reduced relaxation energy, which we introduce to characterize thermally activated CT processes.
The recent development of donor–acceptor copolymers has led to an enormous improvement in the performance of organic solar cells and organic field-effect transistors. Here we describe the synthesis, detailed characterisation, and application of a series of structurally modified copolymers to investigate fundamental structure–property relationships in this class of conjugated polymers. The interplay between chemical structure and optoelectronic properties is investigated. These are further correlated to the charge transport and solar cell performance, which allows us to link their chemical structure to the observed physical properties.
B2 1215+30 is a BL-Lac-type blazar that was first detected at TeV energies by the MAGIC atmospheric Cherenkov telescopes and subsequently confirmed by the Very Energetic Radiation Imaging Telescope Array System (VERITAS) observatory with data collected between 2009 and 2012. In 2014 February 08, VERITAS detected a large-amplitude flare from B2. 1215+30 during routine monitoring observations of the blazar 1ES. 1218+304, located in the same field of view. The TeV flux reached 2.4 times the Crab Nebula flux with a variability timescale of <3.6 hr. Multiwavelength observations with Fermi-LAT, Swift, and the Tuorla Observatory revealed a correlated high GeV flux state and no significant optical counterpart to the flare, with a spectral energy distribution where the gamma-ray luminosity exceeds the synchrotron luminosity. When interpreted in the framework of a onezone leptonic model, the observed emission implies a high degree of beaming, with Doppler factor delta > 10, and an electron population with spectral index p < 2.3.
Alternative electron acceptors are being actively explored in order to advance the development of bulk-heterojunction (BHJ) organic solar cells (OSCs). The indene-C-60 bisadduct (ICBA) has been regarded as a promising candidate, as it provides high open-circuit voltage in BHJ solar cells; however, the photovoltaic performance of such ICBA-based devices is often inferior when compared to cells with the omnipresent PCBM electron acceptor. Here, by pairing the high performance polymer (FTAZ) as the donor with either PCBM or ICBA as the acceptor, we explore the physical mechanism behind the reduced performance of the ICBA-based device. Time delayed collection field (TDCF) experiments reveal reduced, yet field-independent free charge generation in the FTAZ:ICBA system, explaining the overall lower photocurrent in its cells. Through the analysis of the photoluminescence, photogeneration, and electroluminescence, we find that the lower generation efficiency is neither caused by inefficient exciton splitting, nor do we find evidence for significant energy back-transfer from the CT state to singlet excitons. In fact, the increase in open circuit voltage when replacing PCBM by ICBA is entirely caused by the increase in the CT energy, related to the shift in the LUMO energy, while changes in the radiative and nonradiative recombination losses are nearly absent. On the other hand, space charge limited current (SCLC) and bias-assisted charge extraction (BACE) measurements consistently reveal a severely lower electron mobilitiy in the FTAZ:ICBA blend. Studies of the blends with resonant soft X-ray scattering (R-SoXS), grazing incident wide-angle X-ray scattering (GIWAXS), and scanning transmission X-ray microscopy (STXM) reveal very little differences in the mesoscopic morphology but significantly less nanoscale molecular ordering of the fullerene domains in the ICBA based blends, which we propose as the main cause for the lower generation efficiency and smaller electron mobility. Calculations of the JV curves with an analytical model, using measured values, show good agreement with the experimentally determined JV characteristics, proving that these devices suffer from slow carrier extraction, resulting in significant bimolecular recombination losses. Therefore, this study highlights the importance of high charge carrier mobility for newly synthesized acceptor materials, in addition to having suitable energy levels.
Organic solar cells demonstrate external quantum efficiencies and fill factors approaching those of conventional photovoltaic technologies. However, as compared with the optical gap of the absorber materials, their open-circuit voltage is much lower, largely due to the presence of significant non-radiative recombination. Here, we study a large data set of published and new material combinations and find that non-radiative voltage losses decrease with increasing charge-transfer-state energies. This observation is explained by considering non-radiative charge-transfer-state decay as electron transfer in the Marcus inverted regime, being facilitated by a common skeletal molecular vibrational mode. Our results suggest an intrinsic link between non-radiative voltage losses and electron-vibration coupling, indicating that these losses are unavoidable. Accordingly, the theoretical upper limit for the power conversion efficiency of single-junction organic solar cells would be reduced to about 25.5% and the optimal optical gap increases to (1.45-1.65) eV, that is, (0.2-0.3) eV higher than for technologies with minimized non-radiative voltage losses.
Charge carrier recombination in organic disordered semiconductors is strongly influenced by the thermalization of charge carriers in the density of states (DOS). Measurements of recombination dynamics, conducted under transient or steady-state conditions, can easily be misinterpreted when a detailed understanding of the interplay of thermalization and recombination is missing. To enable adequate measurement analysis, we solve the multiple-trapping problem for recombining charge carriers and analyze it in the transient and steady excitation paradigm for different DOS distributions. We show that recombination rates measured after pulsed excitation are inherently time dependent since recombination gradually slows down as carriers relax in the DOS. When measuring the recombination order after pulsed excitation, this leads to an apparent high-order recombination at short times. As times goes on, the recombination order approaches an asymptotic value. For the Gaussian and the exponential DOS distributions, this asymptotic value equals the recombination order of the equilibrated system under steady excitation. For a more general DOS distribution, the recombination order can also depend on the carrier density, under both transient and steady-state conditions. We conclude that transient experiments can provide rich information about recombination in and out of equilibrium and the underlying DOS occupation provided that consistent modeling of the system is performed.
In the strong coupling regime, exciton and plasmon excitations are hybridized into combined system excitations. The correct identification of the coupling regime in these systems is currently debated, from both experimental and theoretical perspectives. In this article we show that the extinction spectra may show a large peak splitting, although the energy loss encoded in the absorption spectra clearly rules out the strong coupling regime. We investigate the coupling of J-aggregate excitons to the localized surface plasmon polaritons on gold nanospheres and nanorods by fine-tuning the plasmon resonance via layer-by-layer deposition of polyelectrolytes. While both structures show a characteristic anticrossing in extinction and scattering experiments, the careful assessment of the systems’ light absorption reveals that strong coupling of the plasmon to the exciton is not present in the nanosphere system. In a phenomenological model of two classical coupled oscillators, a Fano-like regime causes only the resonance of the light-driven oscillator to split up, while the other one still dissipates energy at its original frequency. Only in the strong-coupling limit do both oscillators split up the frequencies at which they dissipate energy, qualitatively explaining our experimental finding.
Perovskite solar cells now compete with their inorganic counterparts in terms of power conversion efficiency, not least because of their small open-circuit voltage (V-OC) losses. A key to surpass traditional thin-film solar cells is the fill factor (FF). Therefore, more insights into the physical mechanisms that define the bias dependence of the photocurrent are urgently required. In this work, we studied charge extraction and recombination in efficient triple cation perovskite solar cells with undoped organic electron/hole transport layers (ETL/HTL). Using integral time of flight we identify the transit time through the HTL as the key figure of merit for maximizing the fill factor (FF) and efficiency. Complementarily, intensity dependent photocurrent and V-OC measurements elucidate the role of the HTL on the bias dependence of non-radiative and transport-related loss channels. We show that charge transport losses can be completely avoided under certain conditions, yielding devices with FFs of up to 84%. Optimized cells exhibit power conversion efficiencies of above 20% for 6 mm(2) sized pixels and 18.9% for a device area of 1 cm(2). These are record efficiencies for hybrid perovskite devices with dopant-free transport layers, highlighting the potential of this device technology to avoid charge-transport limitations and to approach the Shockley-Queisser limit.
Floating ice shelves, which fringe most of Antarctica’s coastline, regulate ice flow into the Southern Ocean1,2,3. Their thinning4,5,6,7 or disintegration8,9 can cause upstream acceleration of grounded ice and raise global sea levels. So far the effect has not been quantified in a comprehensive and spatially explicit manner. Here, using a finite-element model, we diagnose the immediate, continent-wide flux response to different spatial patterns of ice-shelf mass loss. We show that highly localized ice-shelf thinning can reach across the entire shelf and accelerate ice flow in regions far from the initial perturbation. As an example, this ‘tele-buttressing’ enhances outflow from Bindschadler Ice Stream in response to thinning near Ross Island more than 900 km away. We further find that the integrated flux response across all grounding lines is highly dependent on the location of imposed changes: the strongest response is caused not only near ice streams and ice rises, but also by thinning, for instance, well-within the Filchner–Ronne and Ross Ice Shelves. The most critical regions in all major ice shelves are often located in regions easily accessible to the intrusion of warm ocean waters10,11,12, stressing Antarctica’s vulnerability to changes in its surrounding ocean.
Significant progress has been made in recent years in understanding acceleration mechanisms in the Earth's radiation belts. In particular, a number of studies demonstrated the importance of the local acceleration by analyzing the radial profiles of phase space density (PSD) and observing building up peaks in PSD. In this study, we focus on understanding of the local loss using very similar tools. The profiles of PSD for various values of the first adiabatic invariants during the previously studied 17 January 2013 storm are presented and discussed. The profiles of PSD show clear deepening minimums consistent with the scattering by electromagnetic ion cyclotron waves. Long-term evolution shows that local minimums in PSD can persist for relatively long times. During considered interval of time the deepening minimums were observed around L* = 4 during 17 January 2013 storm and around L* = 3.5 during 1 March 2013 storm. This study shows a new method that can help identify the location, magnitude, and time of the local loss and will help quantify local loss in the future. This study also provides additional clear and definitive evidence that local loss plays a major role for the dynamics of the multi-MeV electrons.
gamma Cassiopeia (gamma Cas), is known to be a binary system consisting of a Be-type star and a low-mass (M similar to 1M(circle dot)) companion of unknown nature orbiting in the Be-disc plane. Here, we apply the quasi-spherical accretion theory on to a compact magnetized star and show that if the low-mass companion of gamma Cas is a fast spinning neutron star, the key observational signatures of. Cas are remarkably well reproduced. Direct accretion on to this fast rotating neutron star is impeded by the propeller mechanism. In this case, around the neutron star magnetosphere a hot shell is formed which emits thermal X-rays in qualitative and quantitative agreement with observed properties of the X-ray emission from gamma Cas. We suggest that gamma Cas and its analogues constitute a new subclass of Be-type X-ray binaries hosting rapidly rotating neutron stars formed in supernova explosions with small kicks. The subsequent evolutionary stage of gamma Cas and its analogues should be the X Per-type binaries comprising low-luminosity slowly rotating X-ray pulsars. The model explains the enigmatic X-ray emission from gamma Cas, and also establishes evolutionary connections between various types of rotating magnetized neutron stars in Be-binaries.
We present the first SB2 orbital solution and disentanglement of the massive Wolf-Rayet binary R145 (P = 159 d) located in the Large Magellanic Cloud. The primary was claimed to have a stellar mass greater than 300 M-circle dot, making it a candidate for being the most massive star known to date. While the primary is a known late-type, H-rich Wolf-Rayet star (WN6h), the secondary has so far not been unambiguously detected. Using moderate-resolution spectra, we are able to derive accurate radial velocities for both components. By performing simultaneous orbital and polarimetric analyses, we derive the complete set of orbital parameters, including the inclination. The spectra are disentangled and spectroscopically analyzed, and an analysis of the wind-wind collision zone is conducted. The disentangled spectra and our models are consistent with a WN6h type for the primary and suggest that the secondary is an O3.5 If*/WN7 type star. We derive a high eccentricity of e = 0 : 78 and minimum masses of M-1 sin(3) i approximate to M-2 sin(3) i = 13 +/- 2 M-circle dot, with q = M-2/M-1 = 1.01 +/- 0.07. An analysis of emission excess stemming from a wind-wind collision yields an inclination similar to that obtained from polarimetry (i = 39 +/- 6 degrees). Our analysis thus implies M-1 = 53(-20)(+40) and M2 = 54(-20)(+40) M-circle dot, excluding M-1 > 300 M-circle dot. A detailed comparison with evolution tracks calculated for single and binary stars together with the high eccentricity suggests that the components of the system underwent quasi-homogeneous evolution and avoided mass-transfer. This scenario would suggest current masses of approximate to 80 M-circle dot and initial masses of M-i,M-1 approximate to 10(5) and M-i,M-2 approximate to 90 M-circle dot, consistent with the upper limits of our derived orbital masses, and would imply an age of approximate to 2.2 Myr.
What are the physical laws of the mutual interactions of objects bound to cell membranes, such as various membrane proteins or elongated virus particles? To rationalise this, we here investigate by extensive computer simulations mutual interactions of rod-like particles adsorbed on the surface of responsive elastic two-dimensional sheets. Specifically, we quantify sheet deformations as a response to adhesion of such filamentous particles. We demonstrate that tip-to-tip contacts of rods are favoured for relatively soft sheets, while side-by-side contacts are preferred for stiffer elastic substrates. These attractive orientation-dependent substrate-mediated interactions between the rod-like particles on responsive sheets can drive their aggregation and self-assembly. The optimal orientation of the membrane-bound rods is established via responding to the elastic energy profiles created around the particles. We unveil the phase diagramme of attractive–repulsive rod–rod interactions in the plane of their separation and mutual orientation. Applications of our results to other systems featuring membrane-associated particles are also discussed.
The title compounds, [(1R,3R,4R,5R,6S)-4,5-bis(acetyloxy)-7-oxo-2-oxabicyclo-
[4.2.0]octan-3-yl]methyl acetate, C14H18O8, (I), [(1S,4R,5S,6R)-5-acetyloxy-7-
hydroxyimino-2-oxobicyclo[4.2.0]octan-4-yl acetate, C11H15NO6, (II), and
[(3aR,5R,6R,7R,7aS)-6,7-bis(acetyloxy)-2-oxooctahydropyrano[3,2-b]pyrrol-5-
yl]methyl acetate, C14H19NO8, (III), are stable bicyclic carbohydrate derivatives.
They can easily be synthesized in a few steps from commercially available
glycals. As a result of the ring strain from the four-membered rings in (I) and
(II), the conformations of the carbohydrates deviate strongly from the ideal
chair form. Compound (II) occurs in the boat form. In the five-membered
lactam (III), on the other hand, the carbohydrate adopts an almost ideal chair
conformation. As a result of the distortion of the sugar rings, the configurations
of the three bicyclic carbohydrate derivatives could not be determined from
their NMR coupling constants. From our three crystal structure determinations,
we were able to establish for the first time the absolute configurations of all new
stereocenters of the carbohydrate rings.
We study the adsorption–desorption transition of polyelectrolyte chains onto planar, cylindrical and spherical surfaces with arbitrarily high surface charge densities by massive Monte Carlo computer simulations. We examine in detail how the well known scaling relations for the threshold transition—demarcating the adsorbed and desorbed domains of a polyelectrolyte near weakly charged surfaces—are altered for highly charged interfaces. In virtue of high surface potentials and large surface charge densities, the Debye–Hückel approximation is often not feasible and the nonlinear Poisson–Boltzmann approach should be implemented. At low salt conditions, for instance, the electrostatic potential from the nonlinear Poisson–Boltzmann equation is smaller than the Debye–Hückel result, such that the required critical surface charge density for polyelectrolyte adsorption σc increases. The nonlinear relation between the surface charge density and electrostatic potential leads to a sharply increasing critical surface charge density with growing ionic strength, imposing an additional limit to the critical salt concentration above which no polyelectrolyte adsorption occurs at all. We contrast our simulations findings with the known scaling results for weak critical polyelectrolyte adsorption onto oppositely charged surfaces for the three standard geometries. Finally, we discuss some applications of our results for some physical–chemical and biophysical systems.
The gravitational field of a laser pulse of finite lifetime, is investigated in the framework of linearized gravity. Although the effects are very small, they may be of fundamental physical interest. It is shown that the gravitational field of a linearly polarized light pulse is modulated as the norm of the corresponding electric field strength, while no modulations arise for circular polarization. In general, the gravitational field is independent of the polarization direction. It is shown that all physical effects are confined to spherical shells expanding with the speed of light, and that these shells are imprints of the spacetime events representing emission and absorption of the pulse. Nearby test particles at rest are attracted towards the pulse trajectory by the gravitational field due to the emission of the pulse, and they are repelled from the pulse trajectory by the gravitational field due to its absorption. Examples are given for the size of the attractive effect. It is recovered that massless test particles do not experience any physical effect if they are co-propagating with the pulse, and that the acceleration of massless test particles counter-propagating with respect to the pulse is four times stronger than for massive particles
at rest. The similarities between the gravitational effect of a laser pulse and Newtonian gravity in two dimensions are pointed out. The spacetime curvature close to the pulse is compared to that induced by gravitational waves from astronomical sources.
Breaking news from the HST
(2016)
SAO 244567 is a rare example of a star that allows us to witness stellar evolution in real time. Between 1971 and 1990, it changed from a B-type star into the hot central star of the Stingray Nebula. This observed rapid heating has been a mystery for decades, since it is in strong contradiction with the low mass of the star and canonical post-asymptotic giant branch (AGB) evolution. We speculated that SAO 244567 might have suffered from a late thermal pulse (LTP) and obtained new observations with Hubble Space Telescope (HST)/COS to follow the evolution of the surface properties of SAO 244567 and to verify the LTP hypothesis. Our non-LTE spectral analysis reveals that the star cooled significantly since 2002 and that its envelope is now expanding. Therefore, we conclude that SAO 244567 is currently on its way back towards the AGB, which strongly supports the LTP hypothesis. A comparison with state-of-the-art LTP evolutionary calculations shows that these models cannot fully reproduce the evolution of all surface parameters simultaneously, pointing out possible shortcomings of stellar evolution models. Thereby, SAO 244567 keeps on challenging stellar evolution theory and we highly encourage further investigations.
It is quite generally assumed that the overdamped Langevin equation provides a quantitative description of the dynamics of a classical Brownian particle in the long time limit. We establish and investigate a paradigm anomalous diffusion process governed by an underdamped Langevin equation with an explicit time dependence of the system temperature and thus the diffusion and damping coefficients. We show that for this underdamped scaled Brownian motion (UDSBM) the overdamped limit fails to describe the long time behaviour of the system and may practically even not exist at all for a certain range of the parameter values. Thus persistent inertial effects play a non-negligible role even at significantly long times. From this study a general questions on the applicability of the overdamped limit to describe the long time motion of an anomalously diffusing particle arises, with profound consequences for the relevance of overdamped anomalous diffusion models. We elucidate our results in view of analytical and simulations results for the anomalous diffusion of particles in free cooling granular gases.
The strong adhesion of sub-micron sized particles to surfaces is a nuisance, both for removing contaminating colloids from surfaces and for conscious manipulation of particles to create and test novel micro/nano-scale assemblies. The obvious idea of using detergents to ease these processes suffers from a lack of control: the action of any conventional surface-modifying agent is immediate and global. With photosensitive azobenzene containing surfactants we overcome these limitations. Such photo-soaps contain optical switches (azobenzene molecules), which upon illumination with light of appropriate wavelength undergo reversible trans-cis photo-isomerization resulting in a subsequent change of the physico-chemical molecular properties. In this work we show that when a spatial gradient in the composition of trans- and cis- isomers is created near a solid-liquid interface, a substantial hydrodynamic flow can be initiated, the spatial extent of which can be set, e.g., by the shape of a laser spot. We propose the concept of light induced diffusioosmosis driving the flow, which can remove, gather or pattern a particle assembly at a solid-liquid interface. In other words, in addition to providing a soap we implement selectivity: particles are mobilized and moved at the time of illumination, and only across the illuminated area.
We present an X-ray-optical cross-correlator for the soft (> 150 eV) up to the hard X-ray regime based on a molybdenum-silicon superlattice. The cross-correlation is done by probing intensity and position changes of superlattice Bragg peaks caused by photoexcitation of coherent phonons. This approach is applicable for a wide range of X-ray photon energies as well as for a broad range of excitation wavelengths and requires no external fields or changes of temperature. Moreover, the cross-correlator can be employed on a 10 ps or 100 fs time scale featuring up to 50% total X-ray reflectivity and transient signal changes of more than 20%. (C) 2016 Author(s).
We present a temperature and fluence dependent Ultrafast X-Ray Diffraction study of a laser-heated antiferromagnetic dysprosium thin film. The loss of antiferromagnetic order is evidenced by a pronounced lattice contraction. We devise a method to determine the energy flow between the phonon and spin system from calibrated Bragg peak positions in thermal equilibrium. Reestablishing the magnetic order is much slower than the cooling of the lattice, especially around the Néel temperature. Despite the pronounced magnetostriction, the transfer of energy from the spin system to the phonons in Dy is slow after the spin-order is lost.
Recent experiments show that transcription factors (TFs) indeed use the facilitated diffusion mechanism to locate their target sequences on DNA in living bacteria cells: TFs alternate between sliding motion along DNA and relocation events through the cytoplasm. From simulations and theoretical analysis we study the TF-sliding motion for a large section of the DNA-sequence of a common E. coli strain, based on the two-state TF-model with a fast-sliding search state and a recognition state enabling target detection. For the probability to detect the target before dissociating from DNA the TF-search times self-consistently depend heavily on whether or not an auxiliary operator (an accessible sequence similar to the main operator) is present in the genome section. Importantly, within our model the extent to which the interconversion rates between search and recognition states depend on the underlying nucleotide sequence is varied. A moderate dependence maximises the capability to distinguish between the main operator and similar sequences. Moreover, these auxiliary operators serve as starting points for DNA looping with the main operator, yielding a spectrum of target detection times spanning several orders of magnitude. Auxiliary operators are shown to act as funnels facilitating target detection by TFs.
Temperature-memory polymers remember the temperature, where they were deformed recently, enabled by broad thermal transitions. In this study, we explored a series of crosslinked poly[ethylene-co-(vinyl acetate)] networks (cPEVAs) comprising crystallizable polyethylene (PE) controlling units exhibiting a pronounced temperature-memory effect (TME) between 16 and 99 °C related to a broad melting transition (∼100 °C). The nanostructural changes in such cPEVAs during programming and activation of the TME were analyzed via in situ X-ray scattering and specific annealing experiments. Different contributions to the mechanism of memorizing high or low deformation temperatures (Tdeform) were observed in cPEVA, which can be associated to the average PE crystal sizes. At high deformation temperatures (>50 °C), newly formed PE crystals, which are established during cooling when fixing the temporary shape, dominated the TME mechanism. In contrast, at low Tdeform (<50 °C), corresponding to a cold drawing scenario, the deformation led preferably to a disruption of existing large crystals into smaller ones, which then fix the temporary shape upon cooling. The observed mechanism of memorizing a deformation temperature might enable the prediction of the TME behavior and the knowledge based design of other TMPs with crystallizable controlling units.
We define and study in detail utraslow scaled Brownian motion (USBM) characterized by a time dependent diffusion coefficient of the form . For unconfined motion the mean squared displacement (MSD) of USBM exhibits an ultraslow, logarithmic growth as function of time, in contrast to the conventional scaled Brownian motion. In a harmonic potential the MSD of USBM does not saturate but asymptotically decays inverse-proportionally to time, reflecting the highly non-stationary character of the process. We show that the process is weakly non-ergodic in the sense that the time averaged MSD does not converge to the regular MSD even at long times, and for unconfined motion combines a linear lag time dependence with a logarithmic term. The weakly non-ergodic behaviour is quantified in terms of the ergodicity breaking parameter. The USBM process is also shown to be ageing: observables of the system depend on the time gap between initiation of the test particle and start of the measurement of its motion. Our analytical results are shown to agree excellently with extensive computer simulations.
Many chemical reactions in biological cells occur at very low concentrations of constituent molecules. Thus, transcriptional gene-regulation is often controlled by poorly expressed transcription-factors, such as E.coli lac repressor with few tens of copies. Here we study the effects of inherent concentration fluctuations of substrate-molecules on the seminal Michaelis-Menten scheme of biochemical reactions. We present a universal correction to the Michaelis-Menten equation for the reaction-rates. The relevance and validity of this correction for enzymatic reactions and intracellular gene-regulation is demonstrated. Our analytical theory and simulation results confirm that the proposed variance-corrected Michaelis-Menten equation predicts the rate of reactions with remarkable accuracy even in the presence of large non-equilibrium concentration fluctuations. The major advantage of our approach is that it involves only the mean and variance of the substrate-molecule concentration. Our theory is therefore accessible to experiments and not specific to the exact source of the concentration fluctuations.
Stochastic Wilson
(2015)
We consider a simple Markovian class of the stochastic Wilson–Cowan type models of neuronal network dynamics, which incorporates stochastic delay caused by the existence of a refractory period of neurons. From the point of view of the dynamics of the individual elements, we are dealing with a network of non-Markovian stochastic two-state oscillators with memory, which are coupled globally in a mean-field fashion. This interrelation of a higher-dimensional Markovian and lower-dimensional non-Markovian dynamics is discussed in its relevance to the general problem of the network dynamics of complex elements possessing memory. The simplest model of this class is provided by a three-state Markovian neuron with one refractory state, which causes firing delay with an exponentially decaying memory within the two-state reduced model. This basic model is used to study critical avalanche dynamics (the noise sustained criticality) in a balanced feedforward network consisting of the excitatory and inhibitory neurons. Such avalanches emerge due to the network size dependent noise (mesoscopic noise). Numerical simulations reveal an intermediate power law in the distribution of avalanche sizes with the critical exponent around −1.16. We show that this power law is robust upon a variation of the refractory time over several orders of magnitude. However, the avalanche time distribution is biexponential. It does not reflect any genuine power law dependence.
For the calculation of the work in an irreversible pressure-volume change, we propose approxima-tions, which in contrast to the usual representation in the literature reflect the work performed during expansion and compression symmetrically. The calculations are based on the Reversible-Share-Theorem: Is used the force to overcome for calculating the work, so it captures only the configurational reversible work share.
Probably no other field of statistical physics at the borderline of soft matter and biological physics has caused such a flurry of papers as polymer translocation since the 1994 landmark paper by Bezrukov, Vodyanoy, and Parsegian and the study of Kasianowicz in 1996. Experiments, simulations, and theoretical approaches are still contributing novel insights to date, while no universal consensus on the statistical understanding of polymer translocation has been reached. We here collect the published results, in particular, the famous–infamous debate on the scaling exponents governing the translocation process. We put these results into perspective and discuss where the field is going. In particular, we argue that the phenomenon of polymer translocation is non-universal and highly sensitive to the exact specifications of the models and experiments used towards its analysis.
Anomalous diffusion is frequently described by scaled Brownian motion (SBM){,} a Gaussian process with a power-law time dependent diffusion coefficient. Its mean squared displacement is ?x2(t)? [similar{,} equals] 2K(t)t with K(t) [similar{,} equals] t[small alpha]-1 for 0 < [small alpha] < 2. SBM may provide a seemingly adequate description in the case of unbounded diffusion{,} for which its probability density function coincides with that of fractional Brownian motion. Here we show that free SBM is weakly non-ergodic but does not exhibit a significant amplitude scatter of the time averaged mean squared displacement. More severely{,} we demonstrate that under confinement{,} the dynamics encoded by SBM is fundamentally different from both fractional Brownian motion and continuous time random walks. SBM is highly non-stationary and cannot provide a physical description for particles in a thermalised stationary system. Our findings have direct impact on the modelling of single particle tracking experiments{,} in particular{,} under confinement inside cellular compartments or when optical tweezers tracking methods are used.
Wir schlagen einen allgemein anwendbaren Algorithmus vor, der unter Verwendung des Skalarprodukts von Kraft und Weg zum richtigen Vorzeichen in den Gleichungen für die Arbeit und die Potentielle Energie bei reversiblen Prozessen (Druck-Volumen-Änderung, Dehnung, Elektrostatische Wechselwirkung, Hub)führt. Wir zeigen, dass es dabei möglich ist, systemimmanente oder externe Kräfte zu benutzen. Wir zeigen, dass bei Verwendung von systemimmanenten Kräften das Skalarprodukt mit negativem Vorzeichen anzusetzen ist. Zudem ist es sehr wichtig, nötige Vorzeichenwechsel bei den einzelnen Schritten zu beachten. Wir betonen dies, weil gelegentlich übersehen wird, dass ein Vorzeichenwechsel nötig ist, wenn das Wegdifferential ds durch das Höhendifferential dh beziehungsweise durch das Abstandsdifferential dx oder dr ersetzt werden muss.
Molecular motors pulling cargos in the viscoelastic cytosol: how power strokes beat subdiffusion
(2014)
The discovery of anomalous diffusion of larger biopolymers and submicron tracers such as endogenous granules, organelles, or virus capsids in living cells, attributed to the viscoelastic nature of the cytoplasm, provokes the question whether this complex environment equally impacts the active intracellular transport of submicron cargos by molecular motors such as kinesins: does the passive anomalous diffusion of free cargo always imply its anomalously slow active transport by motors, the mean transport distance along microtubule growing sublinearly rather than linearly in time? Here we analyze this question within the widely used two-state Brownian ratchet model of kinesin motors based on the continuous-state diffusion along microtubules driven by a flashing binding potential, where the cargo particle is elastically attached to the motor. Depending on the cargo size, the loading force, the amplitude of the binding potential, the turnover frequency of the molecular motor enzyme, and the linker stiffness we demonstrate that the motor transport may turn out either normal or anomalous, as indeed measured experimentally. We show how a highly efficient normal active transport mediated by motors may emerge despite the passive anomalous diffusion of the cargo, and study the intricate effects of the elastic linker. Under different, well specified conditions the microtubule-based motor transport becomes anomalously slow and thus significantly less efficient.
Diffusion of finite-size particles in two-dimensional channels with random wall configurations
(2014)
Diffusion of chemicals or tracer molecules through complex systems containing irregularly shaped channels is important in many applications. Most theoretical studies based on the famed Fick–Jacobs equation focus on the idealised case of infinitely small particles and reflecting boundaries. In this study we use numerical simulations to consider the transport of finite-size particles through asymmetrical two-dimensional channels. Additionally, we examine transient binding of the molecules to the channel walls by applying sticky boundary conditions. We consider an ensemble of particles diffusing in independent channels, which are characterised by common structural parameters. We compare our results for the long-time effective diffusion coefficient with a recent theoretical formula obtained by Dagdug and Pineda [J. Chem. Phys., 2012, 137, 024107].
We develop a model of stochastic radiation pressure for rotating non-spherical particles and apply the model to circumplanetary dynamics of dust grains. The stochastic properties of the radiation pressure are related to the ensemble-averaged characteristics of the rotating particles, which are given in terms of the rotational time-correlation function of a grain. We investigate the model analytically and show that an ensemble of particle trajectories demonstrates a diffusion-like behaviour. The analytical results are compared with numerical simulations, performed for the motion of the dusty ejecta from Deimos in orbit around Mars. We find that the theoretical predictions are in a good agreement with the simulation results. The agreement however deteriorates at later time, when the impact of non-linear terms, neglected in the analytic approach, becomes significant. Our results indicate that the stochastic modulation of the radiation pressure can play an important role in the circumplanetary dynamics of dust and may in case of some dusty systems noticeably alter an optical depth. (c) 2006 Elsevier Ltd. All rights reserved.
The velocity distribution function of granular gases in the homogeneous cooling state as well as some heated granular gases decays for large velocities as f proportional to exp(-const x nu). That is, its high-energy tail is overpopulated as compared with the Maxwell distribution. At the present time, there is no theory to describe the influence of the tail on the kinetic characteristics of granular gases. We develop an approach to quantify the overpopulated tail and analyze its impact on granular gas properties, in particular on the cooling coefficient. We observe and explain anomalously slow relaxation of the velocity distribution function to its steady state.
Context. Very massive stars pass through the Wolf-Rayet (WR) stage before they finally explode. Details of their evolution have not yet been safely established, and their physics are not well understood. Their spectral analysis requires adequate model atmospheres, which have been developed step by step during the past decades and account in their recent version for line blanketing by the millions of lines from iron and iron-group elements. However, only very few WN stars have been re-analyzed by means of line-blanketed models yet. Aims. The quantitative spectral analysis of a large sample of Galactic WN stars with the most advanced generation of model atmospheres should provide an empirical basis for various studies about the origin, evolution, and physics of the Wolf-Rayet stars and their powerful winds. Methods. We analyze a large sample of Galactic WN stars by means of the Potsdam Wolf-Rayet (PoWR) model atmospheres, which account for iron line blanketing and clumping. The results are compared with a synthetic population, generated from the Geneva tracks for massive star evolution. Results. We obtain a homogeneous set of stellar and atmospheric parameters for the GalacticWN stars, partly revising earlier results. Conclusions. Comparing the results of our spectral analyses of the Galactic WN stars with the predictions of the Geneva evolutionary calculations, we conclude that there is rough qualitative agreement. However, the quantitative discrepancies are still severe, and there is no preference for the tracks that account for the effects of rotation. It seems that the evolution of massive stars is still not satisfactorily understood.
This paper discusses translocation features of the 20S proteasome in order to explain typical proteasome length distributions. We assume that the protein transport depends significantly on the fragment length with some optimal length which is transported most efficiently. By means of a simple one-channel model, we show that this hypothesis can explain both the one- and the three-peak length distributions found in experiments. A possible mechanism of such translocation is provided by so-called fluctuation-driven transport.
Three methods for the determination of the surface tension of liquids based on force measurements namely, the vertical plate method of Wilhelmy, the frame method of Lenard and the ring method of du Nouy are compared and studied in respect of a common principle of correction. It is shown that these three most important force-based methods allow the determination of the surface tension under static conditions. The force components of the corresponding liquid column below the measuring wire obtained for the straight part of the withdrawal curve up to the transition in its curved part provides exact surface tension values. The experimentally accessible value of the force component describes the physical background of the measured value correction contrary to the approximate equations obtained by mathematical way. Usually the determination of surface tension of liquids is based merely at the vertical plate method on exact equations thermodynamically derived whereas in the case of the frame and ring methods correction factors in approximate equations are used. At usual application of the force-based methods under the non-static condition of the withdrawal of a liquid column, the force maximum measured at withdrawal of the measuring object (plate, frame, or ring) is the basis for the determination of surface tension. In these cases, the measured surface tension values are compensated by correction equations for the frame and ring methods which are based on an correction factor and correction tables empirically obtained. The surface tension values obtained in this usual way agree with those obtained by using the force component of the corresponding liquid column below the measuring wire for the straight part of the withdrawal curve up to the transition in its curved part. Problems arising at the force measurements with increasing thickness of the measuring wires inside and outside the rings are discussed.
Recurrence plot analyses suggest a novel reference system involved in newborn spontaneous movements
(2006)
The movements of newborns have been thoroughly studied in terms of reflexes, muscle synergies, leg coordination, and target-directed arm/hand movements. Since these approaches have concentrated mainly on separate accomplishments, there has remained a clear need for more integrated investigations. Here, we report an inquiry in which we explicitly concentrated on taking such a perspective and, additionally, were guided by the methodological concept of home base behavior, which Ilan Golard developed for studies of exploratory behavior in animals. Methods from nonlinear dynamics, such as symbolic dynamics and recurrence plot analyses of kinematic data received from audiovisual newborn recordings, yielded new insights into the spatial and temporal organization of limb movements. In the framework of home base behavior, our approach uncovered a novel reference system of spontaneous newborn movements.
Experimental results show that the polymerization of pyrrole in the presence of beta-naphthalenesulfonic acid and different fluorosurfactants like perfluorooctanesulfonic acid, perfluorooctyldiethanolamide, and ammonium perfluorooctanoate leads to polypyrrole with special morphologies, such as rings or disks and rectangular frames or plates. The formation of these unusually shaped particles of polymer dispersions is explained by the chemical and colloidal peculiarities of the oxidative pyrrole polymerization with ammonium peroxodisulfate in aqueous medium.
Motivated by the successful Karlsruhe dynamo experiment, a relatively low-dimensional dynamo model is proposed. It is based on a strong truncation of the magnetohydrodynamic (MHD) equations with an external forcing of the Roberts type and the requirement that the model system satisfies the symmetries of the full MHD system, so that the first symmetry-breaking bifurcations can be captured. The backbone of the Roberts dynamo is formed by the Roberts flow, a helical mean magnetic field and another part of the magnetic field coupled to these two by triadic mode interactions. A minimum truncation model (MTM) containing only these energetically dominating primary mode triads is fully equivalent to the widely used first-order smoothing approximation. However, it is shown that this approach works only in the limit of small wave numbers of the excited magnetic field or small magnetic Reynolds numbers ($Rm ll 1$). To obtain dynamo action under more general conditions, secondary mode