45824
2016
2016
eng
33561
33568
8
6
article
Royal Society of Chemistry
Cambridge
1
--
--
--
"Green" gold nanotriangles: synthesis, purification by polyelectrolyte/micelle depletion flocculation and performance in surface-enhanced Raman scattering
The aim of this study was to develop a one-step synthesis of gold nanotriangles (NTs) in the presence of mixed phospholipid vesicles followed by a separation process to isolate purified NTs. Negatively charged vesicles containing AOT and phospholipids, in the absence and presence of additional reducing agents (polyampholytes, polyanions or low molecular weight compounds), were used as a template phase to form anisotropic gold nanoparticles. Upon addition of the gold chloride solution, the nucleation process is initiated and both types of particles, i.e., isotropic spherical and anisotropic gold nanotriangles, are formed simultaneously. As it was not possible to produce monodisperse nanotriangles with such a one-step procedure, the anisotropic nanoparticles needed to be separated from the spherical ones. Therefore, a new type of separation procedure using combined polyelectrolyte/micelle depletion flocculation was successfully applied. As a result of the different purification steps, a green colored aqueous dispersion was obtained containing highly purified, well-defined negatively charged flat nanocrystals with a platelet thickness of 10 nm and an edge length of about 175 nm. The NTs produce promising results in surface-enhanced Raman scattering.
RSC Advances
10.1039/c6ra04808k
2046-2069
wos2016:2019
WOS:000374045000042
Koetz, J (reprint author), Univ Potsdam, Inst Chem, Karl Liebknecht Str 24-25, D-14476 Potsdam, Germany., koetz@uni-potsdam.de
importub
2020-03-22T21:45:02+00:00
filename=package.tar
cee328e23255d54565cba11c84ed6cd5
Ferenc Liebig
Radwan Mohamed Sarhan
Claudia Christina Prietzel
Antje Reinecke
Joachim Koetz
Institut für Physik und Astronomie
Institut für Chemie
Referiert
Import
45843
2016
2016
eng
2593
2603
11
12
article
Royal Society of Chemistry
Cambridge
1
--
--
--
A comparative study of photoinduced deformation in azobenzene containing polymer films
In this paper two groups supporting different views on the mechanism of light induced polymer deformation argue about the respective underlying theoretical conceptions, in order to bring this interesting debate to the attention of the scientific community. The group of Prof. Nicolae Hurduc supports the model claiming that the cyclic isomerization of azobenzenes may cause an athermal transition of the glassy azobenzene containing polymer into a fluid state, the so-called photo-fluidization concept. This concept is quite convenient for an intuitive understanding of the deformation process as an anisotropic flow of the polymer material. The group of Prof. Svetlana Santer supports the re-orientational model where the mass-transport of the polymer material accomplished during polymer deformation is stated to be generated by the light-induced re-orientation of the azobenzene side chains and as a consequence of the polymer backbone that in turn results in local mechanical stress, which is enough to irreversibly deform an azobenzene containing material even in the glassy state. For the debate we chose three polymers differing in the glass transition temperature, 32 degrees C, 87 degrees C and 95 degrees C, representing extreme cases of flexible and rigid materials. Polymer film deformation occurring during irradiation with different interference patterns is recorded using a homemade set-up combining an optical part for the generation of interference patterns and an atomic force microscope for acquiring the kinetics of film deformation. We also demonstrated the unique behaviour of azobenzene containing polymeric films to switch the topography in situ and reversibly by changing the irradiation conditions. We discuss the results of reversible deformation of three polymers induced by irradiation with intensity (IIP) and polarization (PIP) interference patterns, and the light of homogeneous intensity in terms of two approaches: the re-orientational and the photo-fluidization concepts. Both agree in that the formation of opto-mechanically induced stresses is a necessary prerequisite for the process of deformation. Using this argument, the deformation process can be characterized either as a flow or mass transport.
Soft matter
10.1039/c6sm00029k
26853516
1744-683X
1744-6848
wos2016:2019
WOS:000371535900012
Santer, S (reprint author), Univ Potsdam, Inst Phys & Astron, Dept Expt Phys, D-14476 Potsdam, Germany.; Hurduc, N (reprint author), Gheorghe Asachi Tech Univ Iasi, Dept Nat & Synthet Polymers, Prof Dimitrie Mangeron St 73, Iasi 700050, Romania., nhurduc@ch.tuiasi.ro; santer@uni-potsdam.de
importub
2020-03-22T21:55:01+00:00
filename=package.tar
508014dabdbfbc5f8cc3bee4cadf5b9b
Nataraja Sekhar Yadavalli
Sarah Loebner
Thomas Papke
Elena Sava
Nicolae Hurduc
Svetlana A. Santer
Institut für Physik und Astronomie
Referiert
Import
44952
2016
2016
eng
15
18
article
IOP Publ. Ltd.
Bristol
1
--
--
--
A minimal model of self-consistent partial synchrony
We show that self-consistent partial synchrony in globally coupled oscillatory ensembles is a general phenomenon. We analyze in detail appearance and stability properties of this state in possibly the simplest setup of a biharmonic Kuramoto-Daido phase model as well as demonstrate the effect in limit-cycle relaxational Rayleigh oscillators. Such a regime extends the notion of splay state from a uniform distribution of phases to an oscillating one. Suitable collective observables such as the Kuramoto order parameter allow detecting the presence of an inhomogeneous distribution. The characteristic and most peculiar property of self-consistent partial synchrony is the difference between the frequency of single units and that of the macroscopic field.
NEW JOURNAL OF PHYSICS
10.1088/1367-2630/18/9/093037
1367-2630
wos2016:2019
093037
WOS:000385516400006
Rosenblum, M (reprint author), Univ Potsdam, Dept Phys & Astron, Karl Libknecht Str 24-25, D-14476 Potsdam, Germany., pau.clusella@abdn.ac.uk
EU project COSMOS [642563]
importub
2020-03-22T14:28:01+00:00
filename=package.tar
72e45b1e4d13fe1c590ab0e62bc95aba
<a href="https://doi.org/10.25932/publishup-43626">Zweitveröffentlichung in der Schriftenreihe Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe ; 890</a>
Pau Clusella
Antonio Politi
Michael Rosenblum
eng
uncontrolled
synchronization
eng
uncontrolled
collective dynamics
eng
uncontrolled
coupled oscillators
Institut für Physik und Astronomie
Referiert
Import
9140
2016
2016
eng
9
6
article
Nature Publishing Group
London
1
--
2016-04-26
--
A New Figure of Merit for Organic Solar Cells with Transport-limited Photocurrents
Compared to their inorganic counterparts, organic semiconductors suffer from relatively low charge carrier mobilities. Therefore, expressions derived for inorganic solar cells to correlate characteristic performance parameters to material properties are prone to fail when applied to organic devices. This is especially true for the classical Shockley-equation commonly used to describe current-voltage (JV)-curves, as it assumes a high electrical conductivity of the charge transporting material. Here, an analytical expression for the JV-curves of organic solar cells is derived based on a previously published analytical model. This expression, bearing a similar functional dependence as the Shockley-equation, delivers a new figure of merit α to express the balance between free charge recombination and extraction in low mobility photoactive materials. This figure of merit is shown to determine critical device parameters such as the apparent series resistance and the fill factor.
Scientific reports
10.1038/srep24861
2045-2322
Universität Potsdam, Publikationsfonds
PA 2016_16
1386.35
online registration
24861
<a href="http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-91414">Zweitveröffentlichung in der Schriftenreihe Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe ; 225</a>
CC-BY - Namensnennung 4.0 International
Dieter Neher
Juliane Kniepert
Arik Elimelech
L. Jan Anton Koster
eng
uncontrolled
Electronic and spintronic devices
eng
uncontrolled
Semiconductors
Datenverarbeitung; Informatik
Institut für Physik und Astronomie
Referiert
Publikationsfonds der Universität Potsdam
Open Access
Universität Potsdam
9141
2016
eng
9
postprint
1
--
--
--
A New Figure of Merit for Organic Solar Cells with Transport-limited Photocurrents
Compared to their inorganic counterparts, organic semiconductors suffer from relatively low charge carrier mobilities. Therefore, expressions derived for inorganic solar cells to correlate characteristic performance parameters to material properties are prone to fail when applied to organic devices. This is especially true for the classical Shockley-equation commonly used to describe current-voltage (JV)-curves, as it assumes a high electrical conductivity of the charge transporting material. Here, an analytical expression for the JV-curves of organic solar cells is derived based on a previously published analytical model. This expression, bearing a similar functional dependence as the Shockley-equation, delivers a new figure of merit α to express the balance between free charge recombination and extraction in low mobility photoactive materials. This figure of merit is shown to determine critical device parameters such as the apparent series resistance and the fill factor.
urn:nbn:de:kobv:517-opus4-91414
online registration
Universität Potsdam, Publikationsfonds
PA 2016_16
1386.35
<a href="http://publishup.uni-potsdam.de/opus4-ubp/frontdoor/index/index/docId/9140">Bibliographieeintrag der Originalveröffentlichung/Quelle</a>
CC-BY - Namensnennung 4.0 International
Dieter Neher
Juliane Kniepert
Arik Elimelech
L. Jan Anton Koster
Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
225
eng
uncontrolled
Electronic and spintronic devices
eng
uncontrolled
Semiconductors
Datenverarbeitung; Informatik
open_access
Institut für Physik und Astronomie
Referiert
Open Access
Universität Potsdam
https://publishup.uni-potsdam.de/files/9141/pmnr225.pdf
45416
2016
2016
eng
E2348
E2349
9
6
article
Nature Publ. Group
London
1
--
--
--
A New Figure of Merit for Organic Solar Cells with Transport-limited Photocurrents
Compared to their inorganic counterparts, organic semiconductors suffer from relatively low charge carrier mobilities. Therefore, expressions derived for inorganic solar cells to correlate characteristic performance parameters to material properties are prone to fail when applied to organic devices. This is especially true for the classical Shockley-equation commonly used to describe current-voltage (JV)-curves, as it assumes a high electrical conductivity of the charge transporting material. Here, an analytical expression for the JV-curves of organic solar cells is derived based on a previously published analytical model. This expression, bearing a similar functional dependence as the Shockley-equation, delivers a new figure of merit a to express the balance between free charge recombination and extraction in low mobility photoactive materials. This figure of merit is shown to determine critical device parameters such as the apparent series resistance and the fill factor.
Scientific reports
10.1038/srep24861
27112905
2045-2322
wos2016:2019
24861
WOS:000374757300001
Neher, D (reprint author), Univ Potsdam, Inst Phys & Astron, D-14476 Potsdam, Germany., neher@uni-potsdam.de
importub
2020-03-22T18:21:01+00:00
filename=package.tar
3b1e0ee9a8f09f9242340a87ade0b53c
Dieter Neher
Juliane Kniepert
Arik Elimelech
L. Jan Anton Koster
Institut für Physik und Astronomie
Referiert
Import
39809
2016
2016
eng
135
doctoralthesis
1
--
--
--
A quantitative model of spatial correlations in parametric down conversion for investigating complementarity at a double slit
online registration
Dissertation, Universität Potsdam, 2016
Robert Marx
Astronomie und zugeordnete Wissenschaften
Institut für Physik und Astronomie
Universität Potsdam
Universität Potsdam
45604
2016
2016
eng
6
818
article
IOP Publ. Ltd.
Bristol
1
--
--
--
A SEARCH FOR BRIEF OPTICAL FLASHES ASSOCIATED WITH THE SETI TARGET KIC 8462852
The F-type star KIC. 8462852 has recently been identified as an exceptional target for search for extraterrestrial intelligence (SETI) observations. We describe an analysis methodology for optical SETI, which we have used to analyze nine hours of serendipitous archival observations of KIC. 8462852 made with the VERITAS gamma-ray observatory between 2009 and 2015. No evidence of pulsed optical beacons, above a pulse intensity at the Earth of approximately 1 photon m(-2), is found. We also discuss the potential use of imaging atmospheric Cherenkov telescope arrays in searching for extremely short duration optical transients in general.
The astrophysical journal : an international review of spectroscopy and astronomical physics ; Part 2, Letters
10.3847/2041-8205/818/2/L33
2041-8205
2041-8213
wos2016:2019
L33
WOS:000370444800012
Dickinson, HJ (reprint author), Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA.; Holder, J (reprint author), Univ Delaware, Dept Phys & Astron, Newark, DE 19716 USA.; Holder, J (reprint author), Univ Delaware, Bartol Res Inst, Newark, DE 19716 USA.; Holder, J (reprint author), Florida Inst Technol, Dept Phys & Space Sci, W Melbourne, FL 32901 USA., hughd@iastate.edu; jholder@physics.udel.edu
U.S. Department of Energy Office of Science; U.S. National Science Foundation; Smithsonian Institution; NSERC in Canada
importub
2020-03-22T19:55:01+00:00
filename=package.tar
c286dd75d0f30aecbb7b257750b890ab
A. U. Abeysekara
S. Archambault
A. Archer
W. Benbow
R. Bird
M. Buchovecky
J. H. Buckley
K. Byrum
J. V. Cardenzana
M. Cerruti
Xuhui Chen
J. L. Christiansen
L. Ciupik
W. Cui
H. J. Dickinson
J. D. Eisch
M. Errando
A. Falcone
D. J. Fegan
Q. Feng
J. P. Finley
H. Fleischhack
P. Fortin
L. Fortson
A. Furniss
G. H. Gillanders
S. Griffin
J. Grube
G. Gyuk
M. Huetten
Nils Hakansson
D. Hanna
J. Holder
T. B. Humensky
C. A. Johnson
P. Kaaret
P. Kar
N. Kelley-Hoskins
M. Kertzman
D. Kieda
M. Krause
F. Krennrich
S. Kumar
M. J. Lang
T. T. Y. Lin
G. Maier
S. McArthur
A. McCann
K. Meagher
P. Moriarty
R. Mukherjee
D. Nieto
R. A. Ong
A. N. Otte
N. Park
J. S. Perkins
A. Petrashyk
Martin Pohl
A. Popkow
Elisa Pueschel
J. Quinn
K. Ragan
G. Ratliff
P. T. Reynolds
G. T. Richards
E. Roache
M. Santander
G. H. Sembroski
K. Shahinyan
D. Staszak
Igor O. Telezhinsky
J. V. Tucci
J. Tyler
S. Vincent
S. P. Wakely
O. M. Weiner
A. Weinstein
D. A. Williams
B. Zitzer
eng
uncontrolled
astrobiology
eng
uncontrolled
extraterrestrial intelligence
eng
uncontrolled
methods: observational
eng
uncontrolled
stars: individual ( KIC 8462852)
eng
uncontrolled
techniques: photometric
Institut für Physik und Astronomie
Referiert
Import
44746
2016
2016
eng
7
831
article
IOP Publ. Ltd.
Bristol
1
--
--
--
A SEARCH FOR VERY HIGH ENERGY GAMMA RAYS FROM THE MISSING LINK BINARY PULSAR J1023+0038 WITH VERITAS
The binary millisecond radio pulsar PSR J1023+0038 exhibits many characteristics similar to the gamma-ray binary system PSR B1259-63/LS 2883, making it an ideal candidate for the study of high-energy nonthermal emission. It has been the subject of multiwavelength campaigns following the disappearance of the pulsed radio emission in 2013 June, which revealed the appearance of an accretion disk around the neutron star. We present the results of very high energy (VHE) gamma-ray observations carried out by the Very Energetic Radiation Imaging Telescope Array System before and after this change of state. Searches for steady and pulsed emission of both data sets yield no significant gamma-ray signal above 100 GeV, and upper limits are given for both a steady and pulsed gamma-ray flux. These upper limits are used to constrain the magnetic field strength in the shock region of the PSR J1023+0038 system. Assuming that VHE gamma rays are produced via an inverse Compton mechanism in the shock region, we constrain the shock magnetic field to be greater than similar to 2 G before the disappearance of the radio pulsar and greater than similar to 10 G afterward.
The astrophysical journal : an international review of spectroscopy and astronomical physics
10.3847/0004-637X/831/2/193
0004-637X
1538-4357
wos2016:2019
193
WOS:000388227500004
Aliu, E (reprint author), Columbia Univ, Barnard Coll, Dept Phys & Astron, New York, NY 10027 USA., ester.aliu.fuste@gmail.com; gtrichards@gatech.edu; masha.chernyakova@dcu.ie; malloryr@gmail.com
U.S. Department of Energy Office of Science; Smithsonian Institution; NSERC in Canada; Spanish Ministerio de Economia y Competitividad (MINECO) [AYA2013-47447-C3-1-P]; U.S. National Science Foundation
importub
2020-03-22T12:45:01+00:00
filename=package.tar
d63cd1943bb5be74d6c2011b7a43eaa9
E. Aliu
S. Archambault
A. Archer
W. Benbow
R. Bird
Jonathan Biteau
M. Buchovecky
J. H. Buckley
V. Bugaev
K. Byrum
J. V. Cardenzana
M. Cerruti
Xuhui Chen
L. Ciupik
M. P. Connolly
W. Cui
H. J. Dickinson
J. D. Eisch
A. Falcone
Q. Feng
J. P. Finley
H. Fleischhack
A. Flinders
P. Fortin
L. Fortson
A. Furniss
G. H. Gillanders
S. Griffin
J. Grube
G. Gyuk
M. Huetten
Nils Hakansson
J. Holder
T. B. Humensky
C. A. Johnson
P. Kaaret
P. Kar
N. Kelley-Hoskins
M. Kertzman
D. Kieda
M. Krause
M. J. Lang
A. Loo
G. Maier
S. McArthur
A. McCann
K. Meagher
P. Moriarty
R. Mukherjee
T. Nguyen
D. Nieto
R. A. Ong
A. N. Otte
D. Pandel
N. Park
V. Pelassa
A. Petrashyk
M. Pohl
A. Popkow
Elisa Pueschel
J. Quinn
K. Ragan
P. T. Reynolds
G. T. Richards
E. Roache
C. Rulten
M. Santander
G. H. Sembroski
K. Shahinyan
A. W. Smith
D. Staszak
Igor O. Telezhinsky
J. V. Tucci
J. Tyler
A. Varlotta
S. Vincent
S. P. Wakely
O. M. Weiner
A. Weinstein
Alina Wilhelm
D. A. Williams
B. Zitzer
M. Chernyakova
M. S. E. Roberts
eng
uncontrolled
binaries: general
eng
uncontrolled
gamma rays: general
eng
uncontrolled
pulsars: general
eng
uncontrolled
pulsars: individual (PSR J1023+0038)
Institut für Physik und Astronomie
Referiert
Import
45052
2016
2016
eng
1799
1807
9
10
article
Copernicus
Göttingen
1
--
--
--
A simple equation for the melt elevation feedback of ice sheets
In recent decades, the Greenland Ice Sheet has been losing mass and has thereby contributed to global sea-level rise. The rate of ice loss is highly relevant for coastal protection worldwide. The ice loss is likely to increase under future warming. Beyond a critical temperature threshold, a meltdown of the Greenland Ice Sheet is induced by the self-enforcing feedback between its lowering surface elevation and its increasing surface mass loss: the more ice that is lost, the lower the ice surface and the warmer the surface air temperature, which fosters further melting and ice loss. The computation of this rate so far relies on complex numerical models which are the appropriate tools for capturing the complexity of the problem. By contrast we aim here at gaining a conceptual understanding by deriving a purposefully simple equation for the self-enforcing feedback which is then used to estimate the melt time for different levels of warming using three observable characteristics of the ice sheet itself and its surroundings. The analysis is purely conceptual in nature. It is missing important processes like ice dynamics for it to be useful for applications to sea-level rise on centennial timescales, but if the volume loss is dominated by the feedback, the resulting logarithmic equation unifies existing numerical simulations and shows that the melt time depends strongly on the level of warming with a critical slow-down near the threshold: the median time to lose 10% of the present-day ice volume varies between about 3500 years for a temperature level of 0.5 degrees C above the threshold and 500 years for 5 degrees C. Unless future observations show a significantly higher melting sensitivity than currently observed, a complete meltdown is unlikely within the next 2000 years without significant ice-dynamical contributions.
The Cryosphere : TC ; an interactive open access journal of the European Geosciences Union
10.5194/tc-10-1799-2016
1994-0416
1994-0424
wos2016:2019
WOS:000383798200001
Levermann, A (reprint author), Potsdam Inst Climate Impact Res, Potsdam, Germany.; Levermann, A (reprint author), Columbia Univ, LDEO, New York, NY 10027 USA.; Levermann, A (reprint author), Univ Potsdam, Inst Phys, Potsdam, Germany., anders.levermann@pik-potsdam.de
European Union [603864]
importub
2020-03-22T15:18:01+00:00
filename=package.tar
76e0f442ed85d736bd9e3f50ab5a0ba4
Anders Levermann
Hilke Ricarda Winkelmann
Institut für Physik und Astronomie
Referiert
Import