@misc{ZhongCausaMooreetal.2020, author = {Zhong, Yufei and Causa, Martina and Moore, Gareth John and Krauspe, Philipp and Xiao, Bo and G{\"u}nther, Florian and Kublitski, Jonas and BarOr, Eyal and Zhou, Erjun and Banerji, Natalie}, title = {Sub-picosecond charge-transfer at near-zero driving force in polymer:non-fullerene acceptor blends and bilayers}, series = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {1}, issn = {1866-8372}, doi = {10.25932/publishup-51193}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-511936}, pages = {12}, year = {2020}, abstract = {Organic photovoltaics based on non-fullerene acceptors (NFAs) show record efficiency of 16 to 17\% and increased photovoltage owing to the low driving force for interfacial charge-transfer. However, the low driving force potentially slows down charge generation, leading to a tradeoff between voltage and current. Here, we disentangle the intrinsic charge-transfer rates from morphology-dependent exciton diffusion for a series of polymer:NFA systems. Moreover, we establish the influence of the interfacial energetics on the electron and hole transfer rates separately. We demonstrate that charge-transfer timescales remain at a few hundred femtoseconds even at near-zero driving force, which is consistent with the rates predicted by Marcus theory in the normal region, at moderate electronic coupling and at low re-organization energy. Thus, in the design of highly efficient devices, the energy offset at the donor:acceptor interface can be minimized without jeopardizing the charge-transfer rate and without concerns about a current-voltage tradeoff.}, language = {en} } @article{ZhongFuShanShanJiaQianetal.2003, author = {Zhong-Fu, X. and Shan-Shan, M. and Jia-Qian, Z. and Xun-Lin, Q. and Ye-Wen, Z. and Gerhard, Reimund and K{\"u}nstler, Wolfgang}, title = {Piezoelectric activity and its stability of polytetrafluoroethylene (PTFE) films}, year = {2003}, language = {en} } @article{ZhouKurths2005, author = {Zhou, Changsong and Kurths, J{\"u}rgen}, title = {Noise-sustained and controlled synchronization of stirred excitable media by external forcing}, issn = {1367-2630}, year = {2005}, abstract = {Most of the previous studies on constructive effects of noise in spatially extended systems have focused on static media, e.g., of the reaction diffusion type. Because many active chemical or biological processes occur in a fluid environment with mixing, we investigate here the interplay among noise, excitability, mixing and external forcing in excitable media advected by a chaotic flow, in a two-dimensional FitzHugh-Nagumo model described by a set of reaction- advection-diffusion equations. In the absence of external forcing, noise may generate sustained coherent oscillations of the media in a range of noise intensities and stirring rates. We find that these noise-sustained oscillations can be synchronized by external periodic signals much smaller than the threshold. Analysis of the locking regions in the parameter space of the signal period, stirring rate and noise intensity reveals that the mechanism underlying the synchronization behaviour is a matching between the time scales of the forcing signal and the noise-sustained oscillations. The results demonstrate that, in the presence of a suitable level of noise, the stirred excitable media act as self-sustained oscillatory systems and become much easier to be entrained by weak external forcing. Our results may be verified in experiments and are useful to understand the synchronization of population dynamics of oceanic ecological systems by annual cycles}, language = {en} } @article{ZhouKurths2004, author = {Zhou, Changsong and Kurths, J{\"u}rgen}, title = {Resonant patterns in noisy active media}, issn = {1063-651X}, year = {2004}, abstract = {We investigate noise-controlled resonant response of active media to weak periodic forcing, both in excitable and oscillatory regimes. In the excitable regime, we find that noise-induced irregular wave structures can be reorganized into frequency-locked resonant patterns by weak signals with suitable frequencies. The resonance occurs due to a matching condition between the signal frequency and the noise-induced inherent time scale of the media. m:1 resonant regions similar to the Arnold tongues in frequency locking of self-sustained oscillatory media are observed. In the self-sustained oscillatory regime, noise also controls the oscillation frequency and reshapes significantly the Arnold tongues. The combination of noise and weak signal thus could provide an efficient tool to manipulate active extended systems in experiments}, language = {en} } @article{ZhouKurths2006, author = {Zhou, Changsong and Kurths, J{\"u}rgen}, title = {Dynamical weights and enhanced synchronization in adaptive complex networks}, doi = {10.1103/Physrevlett.96.164102}, year = {2006}, abstract = {Dynamical organization of connection weights is studied in scale-free networks of chaotic oscillators, where the coupling strength of a node from its neighbors develops adaptively according to the local synchronization property between the node and its neighbors. We find that when complete synchronization is achieved, the coupling strength becomes weighted and correlated with the topology due to a hierarchical transition to synchronization in heterogeneous networks. Importantly, such an adaptive process enhances significantly the synchronizability of the networks, which could have meaningful implications in the manipulation of dynamical networks}, language = {en} } @article{ZhouKurths2006, author = {Zhou, Changsong and Kurths, J{\"u}rgen}, title = {Hierarchical synchronization in complex networks with heterogeneous degrees}, issn = {1054-1500}, doi = {10.1063/1.2150381}, year = {2006}, abstract = {We study synchronization behavior in networks of coupled chaotic oscillators with heterogeneous connection degrees. Our focus is on regimes away from the complete synchronization state, when the coupling is not strong enough, when the oscillators are under the influence of noise or when the oscillators are nonidentical. We have found a hierarchical organization of the synchronization behavior with respect to the collective dynamics of the network. Oscillators with more connections (hubs) are synchronized more closely by the collective dynamics and constitute the dynamical core of the network. The numerical observation of this hierarchical synchronization is supported with an analysis based on a mean field approximation and the master stability function. (C) 2006 American Institute of Physics}, language = {en} } @article{ZhouKurths2002, author = {Zhou, Changsong and Kurths, J{\"u}rgen}, title = {Noise-induced phase synchronization and synchronization transitions in chaotic oscillators}, year = {2002}, language = {en} } @article{ZhouKurthsHu2001, author = {Zhou, Changsong and Kurths, J{\"u}rgen and Hu, B.}, title = {Array-enhanced coherence resonance: Nontrivial effects of heterogeneity and spatial independence of noise}, year = {2001}, language = {en} } @article{ZhouKurthsKissetal.2002, author = {Zhou, Changsong and Kurths, J{\"u}rgen and Kiss, Istvan Z. and Hudson, J. L.}, title = {Noise-enhanced phase synchronization of chaotic oscillators}, year = {2002}, language = {en} } @article{ZhouMotterKurths2006, author = {Zhou, Changsong and Motter, Adilson E. and Kurths, J{\"u}rgen}, title = {Universality in the synchronization of weighted random networks}, doi = {10.1103/Physrevlett.96.034101}, year = {2006}, abstract = {Realistic networks display not only a complex topological structure, but also a heterogeneous distribution of weights in the connection strengths. Here we study synchronization in weighted complex networks and show that the synchronizability of random networks with a large minimum degree is determined by two leading parameters: the mean degree and the heterogeneity of the distribution of node's intensity, where the intensity of a node, defined as the total strength of input connections, is a natural combination of topology and weights. Our results provide a possibility for the control of synchronization in complex networks by the manipulation of a few parameters}, language = {en} } @article{ZhouZemanovaZamoraetal.2006, author = {Zhou, Changsong and Zemanova, Lucia and Zamora, Gorka and Hilgetag, Claus C. and Kurths, J{\"u}rgen}, title = {Hierarchical organization unveiled by functional connectivity in complex brain networks}, series = {Physical review letters}, volume = {97}, journal = {Physical review letters}, publisher = {American Physical Society}, address = {College Park}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.97.238103}, pages = {4}, year = {2006}, abstract = {How do diverse dynamical patterns arise from the topology of complex networks? We study synchronization dynamics in the cortical brain network of the cat, which displays a hierarchically clustered organization, by modeling each node (cortical area) with a subnetwork of interacting excitable neurons. We find that in the biologically plausible regime the dynamics exhibits a hierarchical modular organization, in particular, revealing functional clusters coinciding with the anatomical communities at different scales. Our results provide insights into the relationship between network topology and functional organization of complex brain networks.}, language = {en} } @phdthesis{Zhou2014, author = {Zhou, Xu}, title = {Atmospheric interactions with land surface in the arctic based on regional climate model solutions}, pages = {143}, year = {2014}, language = {en} } @article{ZhuShpritsSpasojevicetal.2019, author = {Zhu, Hui and Shprits, Yuri Y. and Spasojevic, M. and Drozdov, Alexander}, title = {New hiss and chorus waves diffusion coefficient parameterizations from the Van Allen Probes and their effect on long-term relativistic electron radiation-belt VERB simulations}, series = {Journal of Atmospheric and Solar-Terrestrial Physics}, volume = {193}, journal = {Journal of Atmospheric and Solar-Terrestrial Physics}, publisher = {Elsevier}, address = {Oxford}, issn = {1364-6826}, doi = {10.1016/j.jastp.2019.105090}, pages = {13}, year = {2019}, abstract = {New wave frequency and amplitude models for the nightside and dayside chorus waves are built based on measurements from the Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS) instrument onboard the Van Allen Probes. The corresponding 3D diffusion coefficients are systematically obtained. Compared with previous commonly-used (typical) parameterizations, the new parameterizations result in differences in diffusion rates that depend on the energy and pitch angle. Furthermore, one-year 3D diffusive simulations are performed using the Versatile Electron Radiation Belt (VERB) code. Both typical and new wave parameterizations simulation results are in a good agreement with observations at 0.9 MeV. However, the new parameterizations for nightside chorus better reproduce the observed electron fluxes. These parameterizations will be incorporated into future modeling efforts.}, language = {en} } @article{ZhuKolloscheLuetal.2012, author = {Zhu, Jian and Kollosche, Matthias and Lu, Tongqing and Kofod, Guggi and Suo, Zhigang}, title = {Two types of transitions to wrinkles in dielectric elastomers}, series = {Soft matter}, volume = {8}, journal = {Soft matter}, number = {34}, publisher = {Royal Society of Chemistry}, address = {Cambridge}, issn = {1744-683X}, doi = {10.1039/c2sm26034d}, pages = {8840 -- 8846}, year = {2012}, abstract = {A membrane of a dielectric elastomer coated with compliant electrodes may form wrinkles as the applied voltage is ramped up. We present a combination of experiment and theory to investigate the transition to wrinkles using a clamped membrane subject to a constant force and a voltage ramp. Two types of transitions are identified. In type-I transition, the voltage-stretch curve is N-shaped, and flat and wrinkled regions coexist in separate areas of the membrane. The type-I transition progresses by nucleation of small wrinkled regions, followed by the growth of the wrinkled regions at the expense of the flat regions, until the entire membrane is wrinkled. By contrast, in type-II transition, the voltage-stretch curve is monotonic, and the entire flat membrane becomes wrinkled with no nucleation barrier. The two types of transitions are analogous to the first and the second order phase transitions. While the type-I transition is accompanied by a jump in the vertical displacement, type-II transition is accompanied by a continuous change in the vertical displacement. Such transitions may enable applications in muscle-like actuation and energy harvesting, where large deformation and large energy of conversion are desired.}, language = {en} } @article{ZhuStoyanovKofodetal.2010, author = {Zhu, Jian and Stoyanov, Hristiyan and Kofod, Guggi and Suo, Zhigang}, title = {Large deformation and electromechanical instability of a dielectric elastomer tube actuator}, issn = {0021-8979}, doi = {10.1063/1.3490186}, year = {2010}, abstract = {This paper theoretically analyzes a dielectric elastomer tube actuator (DETA). Subject to a voltage difference between the inner and outer surfaces, the actuator reduces in thickness and expands in length, so that the same voltage will induce an even higher electric field. This positive feedback may cause the actuator to thin down drastically, resulting in electrical breakdown. We obtain an analytical solution of the actuator undergoing finite deformation when the elastomer obeys the neo-Hookean model. The critical strain of actuation is calculated in terms of various parameters of design. We also discuss the effect of the strain-stiffening on electromechanical behavior of DETAs by using the model of freely joined links. (C) 2010 American Institute of Physics. [doi:10.1063/1.3490186]}, language = {en} } @article{ZhuArmbrusterKatzorke2005, author = {Zhu, M. Q. and Armbruster, Dieter and Katzorke, Ines}, title = {Does synchronization of networks of chaotic maps lead to control?}, issn = {1054-1500}, year = {2005}, abstract = {We consider networks of chaotic maps with different network topologies. In each case, they are coupled in such a way as to generate synchronized chaotic solutions. By using the methods of control of chaos we are controlling a single map into a predetermined trajectory. We analyze the reaction of the network to such a control. Specifically we show that a line of one-dimensional logistic maps that are unidirectionally coupled can be controlled from the first oscillator whereas a ring of diffusively coupled maps cannot be controlled for more than 5 maps. We show that rings with more elements can be controlled if every third map is controlled. The dependence of unidirectionally coupled maps on noise is studied. The noise level leads to a finite synchronization lengths for which maps can be controlled by a single location. A two-dimensional lattice is also studied. (C) 2005 American Institute of Physics}, language = {en} } @article{ZhuSchulzBrumaetal.1996, author = {Zhu, Shigen and Schulz, Burkhard and Bruma, Maria and Brehmer, Ludwig}, title = {Comparative study of the thermal properties of related aromatic polyhydrazides and poly(1,3,4-oxadiazole)s}, issn = {1042-7147}, doi = {10.1002/(SICI)1099-1581(199612)7:12<879::AID-PAT600>3.0.CO;2-X}, year = {1996}, language = {en} } @article{ZhuangHolyStangletal.1999, author = {Zhuang, Y. and Hol{\´y}, V{\´a}clav and Stangl, Jochen and Darhuber, A. and Mikulik, P. and Zerlauth, S. and Sch{\"a}ffler, F. and Bauer, G{\"u}nther and Darowski, Nora and L{\"u}bbert, Daniel and Pietsch, Ullrich}, title = {Strain relaxation in periodic arrays of Si/SiGe quantum wires determined by coplanar high-resolution x-ray diffrcation and grazing-incidence diffraction}, year = {1999}, language = {en} } @article{ZhuangPietschStangletal.2000, author = {Zhuang, Y. and Pietsch, Ullrich and Stangl, Jochen and Hol{\´y}, Vaclav and Darowski, Nora and Grenzer, J{\"o}rg and Zerlauth, S. and Sch{\"a}ffler, F. and Bauer, G{\"u}nther}, title = {In-plane strain and shape analysis of Si/SiGe nanostructures by grazing incidence diffraction}, year = {2000}, language = {en} } @article{ZhuangSchellingStangletal.2000, author = {Zhuang, Y. and Schelling, Christoph and Stangl, Jochen and Penn, C. and Senz, S. and Sch{\"a}ffler, Friedrich and Roche, T. and Daniel, A. and Grenzer, J{\"o}rg and Pietsch, Ullrich and Bauer, G{\"u}nther}, title = {Structural and optical properties of Si/Si{1-x}Ge{x} wires}, year = {2000}, language = {en} }