@unpublished{13347, abstract = {{<div> <div> <div> <p>Molecular doping in conjugated polymers is a crucial process for their application in organic photovoltaics and optoelectronics. In the present work we theoretically investigate p-type molecu- lar doping in a series of (poly[2,6-(4,4-bis(2-ethylhexyl)-4H-cyclopenta[2,1-b;3,4-b”]dithiophene)-alt- 4,7-(2,1,3-benzothiadiazole)] (PCPDT-BT) conjugated oligomers with different lengths and three widely-used dopants with different electron affinities, namely F4TCNQ, F6TCNNQ, and CN6-CP. We study in detail the molecular geometry of possible oligomer-dopant complexes and its influence on the doping mechanisms and electronic system properties. We find that the mechanisms of dop- ing and charge transfer observed sensitively depend on the specific geometry of the oligomer-dopant complexes. For a given complex different geometries may exist, some of which show transfer of an entire electron from the oligomer chain onto the dopant molecule resulting in an integer-charge transfer complex, leaving the system in a ground state with broken spin symmetry. In other ge- ometries merely hybridization of oligomer and dopant frontier orbitals occurs with partial charge transfer but spin-symmetric ground state. Considering the resulting electronic density of states both cases may well contribute to an increased electrical conductivity of corresponding film samples while the underlying physical mechanisms are entirely different. </p> </div> </div> </div>}}, author = {{Dong, Chuan-Ding and Schumacher, Stefan}}, title = {{{Molecular Doping of PCPDT-BT Copolymers: Comparison of Molecular Complexes with and Without Integer Charge Transfer}}}, year = {{2019}}, } @article{13343, author = {{Vollbrecht, Joachim and Wiebeler, Christian and Bock, Harald and Schumacher, Stefan and Kitzerow, Heinz-Siegfried}}, issn = {{1932-7447}}, journal = {{The Journal of Physical Chemistry C}}, number = {{7}}, pages = {{4483--4492}}, title = {{{Curved Polar Dibenzocoronene Esters and Imides versus Their Planar Centrosymmetric Homologs: Photophysical and Optoelectronic Analysis}}}, doi = {{10.1021/acs.jpcc.8b10730}}, volume = {{123}}, year = {{2019}}, } @article{50496, abstract = {{Trotz hoher Aktualität und steigender Bedeutung liegen zum Thema Digitalisierung im Sportverein bisher kaum empirische Erkenntnisse vor. Der vorliegende Beitrag setzt sich mit folgenden Fragestellungen auseinander: (i) In welchem Umfang und zu welchem Zweck nutzen Sportvereine digitale Instrumente? (ii) Welche vereinsspezifischen Faktoren determinieren das jeweilige Nutzungsverhalten? Hierzu wurde eine Stichprobe von n=787 Sportvereinen aus Österreich und Deutschland generiert. Es zeigt sich, dass digitale Instrumente vor allem zur internen und externen Kommunikation sowie zur Bewältigung klassischer Verwaltungsaufgaben eingesetzt werden. Das Ausmaß der Nutzung hängt einerseits von vereinsexternen Bedingungen ab. So zeigt sich dahingehend ein Ländereffekt, dass in Deutschland digitale Instrumente stärker genutzt werden als in Österreich. Darüber hinaus haben Auflagen seitens der Verbände zur Verwendung bestimmter Software (z.B. für die Meldung von Wettkampfergebnissen) einen wichtigen Einfluss. Andererseits bestimmen vereinsinterne Faktoren wesentlich das Nutzungsverhalten. Positiv wirken vor allem die Vereinsziele ‚Engagement/Erfolg im Leistungssport‘ und ‚Wollen Vorreiterrolle bei der Digitalisierung einnehmen‘. Negativ wirken eine fehlende Strategie im Umgang mit digitalen Instrumenten sowie die Einschätzung, dass digitale Prozesse nicht zur eigenen Vereinskultur passen. }}, author = {{Riedl, Lars and Ehnold, Peter and Schlesinger, Torsten }}, issn = {{1869-8247}}, journal = {{Sciamus - Sport und Management}}, number = {{4}}, pages = {{21--40}}, title = {{{Digitalisierung im organisierten Sport. Eine Analyse zur Nutzung digitaler Instrumente in Sportvereinen}}}, doi = {{10.24403/jp.1016426}}, year = {{2019}}, } @inproceedings{23764, author = {{Kehne, Franziska and Fechner, Sabine}}, booktitle = {{Naturwissenschaftliche Bildung als Grundlage für berufliche und gesellschaftliche Teilhabe. Gesellschaft für Didaktik der Chemie und Physik, Jahrestagung in Kiel 2018}}, editor = {{Maurer, Christian }}, pages = {{755--758}}, publisher = {{Universität Regensburg}}, title = {{{Enkodierung chemischer Konzepte aus lebenweltlichen Kontexten}}}, year = {{2019}}, } @phdthesis{62824, author = {{Kehne, Franziska}}, publisher = {{Logos Verlag}}, title = {{{Analyse des Transfers von kontextualisiert erworbenem Wissen im Fach Chemie}}}, year = {{2019}}, } @article{59500, author = {{Güsken, Nicholas Alexander and Rieger, Torsten and Mussler, Gregor and Lepsa, Mihail Ion and Grützmacher, Detlev}}, issn = {{1931-7573}}, journal = {{Nanoscale Research Letters}}, number = {{1}}, publisher = {{Springer Science and Business Media LLC}}, title = {{{Influence of Te-Doping on Catalyst-Free VS InAs Nanowires}}}, doi = {{10.1186/s11671-019-3004-0}}, volume = {{14}}, year = {{2019}}, } @article{40384, author = {{Ferreri, Alessandro and Ansari, V. and Silberhorn, Christine and Sharapova, Polina R.}}, issn = {{2469-9926}}, journal = {{Physical Review A}}, number = {{5}}, publisher = {{American Physical Society (APS)}}, title = {{{Temporally multimode four-photon Hong-Ou-Mandel interference}}}, doi = {{10.1103/physreva.100.053829}}, volume = {{100}}, year = {{2019}}, } @article{63177, author = {{Ludwig, M and Jablonski, S}}, issn = {{978-84-9048-661-0}}, title = {{{Doing Math Modelling Outdoors-A Special Math Class Activity designed with MathCityMap}}}, year = {{2019}}, } @inproceedings{63197, author = {{Decker, Claudia and Mochalova, Maria}}, location = {{Universität Osnabrück}}, title = {{{Professionalisierung im Lehramtsstudium an der Universität Paderborn}}}, year = {{2019}}, } @article{63325, abstract = {{Abstract We consider the spatially 2D version of the model $$\begin{equation*} \qquad\quad\left\{ \begin{array}{@{}rcll} n_t + u\cdot\nabla n &=& \Delta n - \nabla \cdot \big(nS(x,n,c) \cdot \nabla c \big), \qquad &\qquad x\in \Omega, \ t&gt;0, \\ c_t + u\cdot \nabla c &=& \Delta c - n f(c), \qquad &\qquad x\in \Omega, \ t&gt;0, \\ u_t &=& \Delta u + \nabla P + n\nabla\phi, \qquad \nabla\cdot u=0, \qquad &\qquad x\in \Omega, \ t&gt;0, \end{array} \right. \qquad \qquad (\star) \end{equation*}$$for nutrient taxis processes, possibly interacting with liquid environments. Here the particular focus is on the situation when the chemotactic sensitivity $S$ is not a scalar function but rather attains general values in ${\mathbb{R}}^{2\times 2}$, thus accounting for rotational flux components in accordance with experimental findings and recent modeling approaches. Reflecting significant new challenges that mainly stem from apparent loss of energy-like structures, especially for initial data with large size, the knowledge on ($\star$) so far seems essentially restricted to results on global existence of certain generalized solutions with possibly quite poor boundedness and regularity properties; widely unaddressed seem aspects related to possible effects of such non-diagonal taxis mechanisms on the qualitative solution behavior, especially with regard to the fundamental question whether spatial structures may thereby be supported. The present work answers the latter in the negative in the following sense: under the assumptions that the initial data $(n_0,c_0,u_0)$ and the parameter functions $S$, $f$, and $\phi$ are sufficiently smooth, and that $S$ is bounded and $f$ is positive on $(0,\infty )$ with $f(0)=0$, it is shown that any nontrivial of these solutions eventually becomes smooth and satisfies $$\begin{equation*} n(\cdot,t)\to - \int_\Omega n_0, \quad c(\cdot,t)\to 0 \quad \text{and} \quad u(\cdot,t)\to 0 \qquad \text{as} \ t\to\infty, \end{equation*}$$uniformly with respect to $x\in \Omega$. By not requiring any smallness condition on the initial data, the latter seems new even in the corresponding fluid-free version obtained on letting $u\equiv 0$ in ($\star$).}}, author = {{Winkler, Michael}}, issn = {{1073-7928}}, journal = {{International Mathematics Research Notices}}, number = {{11}}, pages = {{8106--8152}}, publisher = {{Oxford University Press (OUP)}}, title = {{{Can Rotational Fluxes Impede the Tendency Toward Spatial Homogeneity in Nutrient Taxis(-Stokes) Systems?}}}, doi = {{10.1093/imrn/rnz056}}, volume = {{2021}}, year = {{2019}}, } @article{63337, abstract = {{AbstractIn boundedn-dimensional domainsΩ, the Neumann problem for the parabolic equation$$\begin{array}{} \displaystyle u_t = \nabla \cdot \Big( A(x,t)\cdot\nabla u\Big) + \nabla \cdot \Big(b(x,t)u\Big) - f(x,t,u)+g(x,t) \end{array}$$(*)is considered for sufficiently regular matrix-valuedA, vector-valuedband real valuedg, and withfrepresenting superlinear absorption in generalizing the prototypical choice given byf(⋅, ⋅,s) =sαwithα> 1. Problems of this form arise in a natural manner as sub-problems in several applications such as cross-diffusion systems either of Keller-Segel or of Shigesada-Kawasaki-Teramoto type in mathematical biology, and accordingly a natural space for initial data appears to beL1(Ω).The main objective thus consists in examining how far solutions can be constructed for initial data merely assumed to be integrable, with major challenges potentially resulting from the interplay between nonlinear degradation on the one hand, and the possibly destabilizing drift-type action on the other in such contexts. Especially, the applicability of well-established methods such as techniques relying on entropy-like structures available in some particular cases, for instance, seems quite limited in the present setting, as these typically rely on higher initial regularity properties.The first of the main results shows that in the general framework of (*), nevertheless certain global very weak solutions can be constructed through a limit process involving smooth solutions to approximate variants thereof, provided that the ingredients of the latter satisfy appropriate assumptions with regard to their stabilization behavior.The second and seemingly most substantial part of the paper develops a method by which it can be shown, under suitably stregthened hypotheses on the integrability ofband the degradation parameterα, that the solutions obtained above in fact form genuine weak solutions in a naturally defined sense. This is achieved by properly exploiting a weak integral inequality, as satisfied by the very weak solution at hand, through a testing procedure that appears to be novel and of potentially independent interest.To underline the strength of this approach, both these general results are thereafter applied to two specific cross-diffusion systems. Inter alia, this leads to a statement on global solvability in a logistic Keller-Segel system under the assumptionα>$\begin{array}{} \frac{2n+4}{n+4} \end{array}$on the respective degradation rate which seems substantially milder than any previously found condition in the literature. Apart from that, for a Shigesada-Kawasaki-Teramoto system some apparently first results on global solvability forL1initial data are derived.}}, author = {{Winkler, Michael}}, issn = {{2191-950X}}, journal = {{Advances in Nonlinear Analysis}}, number = {{1}}, pages = {{526--566}}, publisher = {{Walter de Gruyter GmbH}}, title = {{{The role of superlinear damping in the construction of solutions to drift-diffusion problems with initial data in L1}}}, doi = {{10.1515/anona-2020-0013}}, volume = {{9}}, year = {{2019}}, } @article{63334, author = {{Tao, Youshan and Winkler, Michael}}, issn = {{0022-0396}}, journal = {{Journal of Differential Equations}}, number = {{9}}, pages = {{4973--4997}}, publisher = {{Elsevier BV}}, title = {{{Global classical solutions to a doubly haptotactic cross-diffusion system modeling oncolytic virotherapy}}}, doi = {{10.1016/j.jde.2019.10.046}}, volume = {{268}}, year = {{2019}}, } @article{63349, author = {{Bellomo, Nicola and Painter, Kevin J. and Tao, Youshan and Winkler, Michael}}, issn = {{0036-1399}}, journal = {{SIAM Journal on Applied Mathematics}}, number = {{5}}, pages = {{1990--2010}}, publisher = {{Society for Industrial & Applied Mathematics (SIAM)}}, title = {{{Occurrence vs. Absence of Taxis-Driven Instabilities in a May--Nowak Model for Virus Infection}}}, doi = {{10.1137/19m1250261}}, volume = {{79}}, year = {{2019}}, } @article{63350, author = {{Fila, Marek and Winkler, Michael}}, issn = {{0001-8708}}, journal = {{Advances in Mathematics}}, publisher = {{Elsevier BV}}, title = {{{A Gagliardo-Nirenberg-type inequality and its applications to decay estimates for solutions of a degenerate parabolic equation}}}, doi = {{10.1016/j.aim.2019.106823}}, volume = {{357}}, year = {{2019}}, } @article{63355, abstract = {{AbstractThis work studies the two‐species Shigesada–Kawasaki–Teramoto model with cross‐diffusion for one species, as given by with positive parameters and , and nonnegative constants and . Beyond some statements on global existence, the literature apparently provides only few results on qualitative behavior of solutions; in particular, questions related to boundedness as well as to large time asymptotics in seem unsolved so far.In the present paper it is inter alia shown that if and is a bounded convex domain with smooth boundary, then whenever and are nonnegative, the associated Neumann initial‐boundary value problem for possesses a global classical solution which in fact is bounded in the sense that Moreover, the asymptotic behavior of arbitrary nonnegative solutions enjoying the boundedness property is studied in the general situation when is arbitrary and no longer necessarily convex. If , then in both cases and , an explicit smallness condition on is identified as sufficient for stabilization of any nontrivial solutions toward a corresponding unique nontrivial spatially homogeneous steady state. If and , then without any further assumption all nonzero solutions are seen to approach the equilibrium (0,1). As a by‐product, this particularly improves previous knowledge on nonexistence of nonconstant equilibria of .}}, author = {{Tao, Youshan and Winkler, Michael}}, issn = {{0024-6115}}, journal = {{Proceedings of the London Mathematical Society}}, number = {{6}}, pages = {{1598--1632}}, publisher = {{Wiley}}, title = {{{Boundedness and stabilization in a population model with cross‐diffusion for one species}}}, doi = {{10.1112/plms.12276}}, volume = {{119}}, year = {{2019}}, } @article{63356, abstract = {{ This work deals with a taxis cascade model for food consumption in two populations, namely foragers directly orienting their movement upward the gradients of food concentration and exploiters taking a parasitic strategy in search of food via tracking higher forager densities. As a consequence, the dynamics of both populations are adapted to the space distribution of food which is dynamically modified in time and space by the two populations. This model extends the classical one-species chemotaxis-consumption systems by additionally accounting for a second taxis mechanism coupled to the first in a consecutive manner. It is rigorously proved that for all suitably regular initial data, an associated Neumann-type initial-boundary value problem for the spatially one-dimensional version of this model possesses a globally defined bounded classical solution. Moreover, it is asserted that the considered two populations will approach spatially homogeneous distributions in the large time limit, provided that either the total population number of foragers or that of exploiters is appropriately small. }}, author = {{Tao, Youshan and Winkler, Michael}}, issn = {{0218-2025}}, journal = {{Mathematical Models and Methods in Applied Sciences}}, number = {{11}}, pages = {{2151--2182}}, publisher = {{World Scientific Pub Co Pte Ltd}}, title = {{{Large time behavior in a forager–exploiter model with different taxis strategies for two groups in search of food}}}, doi = {{10.1142/s021820251950043x}}, volume = {{29}}, year = {{2019}}, } @article{63352, author = {{Lankeit, Johannes and Winkler, Michael}}, issn = {{0021-2172}}, journal = {{Israel Journal of Mathematics}}, number = {{1}}, pages = {{249--296}}, publisher = {{Springer Science and Business Media LLC}}, title = {{{Counterintuitive dependence of temporal asymptotics on initial decay in a nonlocal degenerate parabolic equation arising in game theory}}}, doi = {{10.1007/s11856-019-1900-8}}, volume = {{233}}, year = {{2019}}, } @article{63358, author = {{Tao, Youshan and Winkler, Michael}}, issn = {{1553-5258}}, journal = {{Communications on Pure & Applied Analysis}}, number = {{4}}, pages = {{2047--2067}}, publisher = {{American Institute of Mathematical Sciences (AIMS)}}, title = {{{A chemotaxis-haptotaxis system with haptoattractant remodeling: Boundedness enforced by mild saturation of signal production}}}, doi = {{10.3934/cpaa.2019092}}, volume = {{18}}, year = {{2019}}, } @article{63357, author = {{Tao, Youshan and Winkler, Michael}}, issn = {{0022-0396}}, journal = {{Journal of Differential Equations}}, number = {{1}}, pages = {{388--406}}, publisher = {{Elsevier BV}}, title = {{{Global smooth solvability of a parabolic–elliptic nutrient taxis system in domains of arbitrary dimension}}}, doi = {{10.1016/j.jde.2019.01.014}}, volume = {{267}}, year = {{2019}}, } @article{63353, author = {{Lankeit, Johannes and Winkler, Michael}}, issn = {{0012-0456}}, journal = {{Jahresbericht der Deutschen Mathematiker-Vereinigung}}, number = {{1}}, pages = {{35--64}}, publisher = {{Springer Fachmedien Wiesbaden GmbH}}, title = {{{Facing Low Regularity in Chemotaxis Systems}}}, doi = {{10.1365/s13291-019-00210-z}}, volume = {{122}}, year = {{2019}}, }