@article{AbdoulCarimeBaldIllenbergeretal.2018, author = {Abdoul-Carime, Hassan and Bald, Ilko and Illenberger, Eugen and Kopyra, Janina}, title = {Selective Synthesis of Ethylene and Acetylene from Dimethyl Sulfide Cold Films Controlled by Slow Electrons}, series = {The journal of physical chemistry : C, Nanomaterials and interfaces}, volume = {122}, journal = {The journal of physical chemistry : C, Nanomaterials and interfaces}, number = {42}, publisher = {American Chemical Society}, address = {Washington}, issn = {1932-7447}, doi = {10.1021/acs.jpcc.8b07377}, pages = {24137 -- 24142}, year = {2018}, abstract = {One of the major challenges in chemical synthesis is to trigger and control a specific reaction route leading to a specific final product, while side products are avoided. Methodologies based on resonant processes at the molecular level, for example, photochemistry, offer the possibility of inducing selective reactions. Electrons at energies below the molecular ionization potential (<10 eV) are known to dissociate molecules via resonant processes with higher cross sections and specificity than photons. Here we show that even subexcitation electrons with energies as low as 1 eV produce ethylene and acetylene from dimethyl sulfide in competing reactions. However, the production of ethylene can specifically be targeted by controlling the energy of electrons (similar to 3 to 4 eV). Finally, pure ethylene is selectively desorbed by heating the substrate from 90 to 105 K. Beyond the synthesis of these versatile hydrocarbons for various industrial applications from a biogenic sulfur compound, our findings demonstrate the feasibility of electron induced selective chemistry applicable on the nanoscale.}, language = {en} } @article{AbelShepelyansky2011, author = {Abel, M. W. and Shepelyansky, Dima L.}, title = {Google matrix of business process management}, series = {The European physical journal : B, Condensed matter and complex systems}, volume = {84}, journal = {The European physical journal : B, Condensed matter and complex systems}, number = {4}, publisher = {Springer}, address = {New York}, issn = {1434-6028}, doi = {10.1140/epjb/e2010-10710-y}, pages = {493 -- 500}, year = {2011}, abstract = {Development of efficient business process models and determination of their characteristic properties are subject of intense interdisciplinary research. Here, we consider a business process model as a directed graph. Its nodes correspond to the units identified by the modeler and the link direction indicates the causal dependencies between units. It is of primary interest to obtain the stationary flow on such a directed graph, which corresponds to the steady-state of a firm during the business process. Following the ideas developed recently for the World Wide Web, we construct the Google matrix for our business process model and analyze its spectral properties. The importance of nodes is characterized by PageRank and recently proposed CheiRank and 2DRank, respectively. The results show that this two-dimensional ranking gives a significant information about the influence and communication properties of business model units. We argue that the Google matrix method, described here, provides a new efficient tool helping companies to make their decisions on how to evolve in the exceedingly dynamic global market.}, language = {en} } @phdthesis{Abel2005, author = {Abel, Markus}, title = {Turbulent flows : transport, analysis and modeling}, address = {Potsdam}, pages = {Getr. Z{\"a}hlung}, year = {2005}, language = {en} } @article{Abel2004, author = {Abel, Markus}, title = {Nonparametric modeling and spatiotemporal dynamical systems}, issn = {0218-1274}, year = {2004}, abstract = {This article describes how to use statistical data analysis to obtain models directly from data. The focus is put on finding nonlinearities within a generalized additive model. These models are found by means of backfitting or more general algorithms, like the alternating conditional expectation value one. The method is illustrated by numerically generated data. As an application, the example of vortex ripple dynamics, a highly complex fluid-granular system, is treated}, language = {en} } @phdthesis{Abel1998, author = {Abel, Markus}, title = {Localization in driven nonlinear lattices}, address = {Potsdam}, pages = {100 S. : graph. Darst.}, year = {1998}, language = {en} } @article{AbelAhnertKurthsetal.2005, author = {Abel, Markus and Ahnert, Karsten and Kurths, R. and Mandelj, S.}, title = {Additive nonparametric reconstruction of dynamical systems from time series}, issn = {1063-651X}, year = {2005}, abstract = {We present a nonparametric way to retrieve an additive system of differential equations in embedding space from a single time series. These equations can be treated with dynamical systems theory and allow for long-term predictions. We apply our method to a modified chaotic Chua oscillator in order to demonstrate its potential}, language = {en} } @article{AbelBergweilerGerhard2006, author = {Abel, Markus and Bergweiler, Steffen and Gerhard, Reimund}, title = {Synchronization of organ pipes : experimental observations and modeling}, issn = {0001-4966}, doi = {10.1121/1.217044}, year = {2006}, abstract = {We report measurements on the synchronization properties of organ pipes. First, we investigate influence of an external acoustical signal from a loudspeaker on the sound of an organ pipe. Second, the mutual influence of two pipes with different pitch is analyzed. In analogy to the externally driven, or mutually coupled self-sustained oscillators, one observes a frequency locking, which can be explained by synchronization theory. Further, we measure the dependence of the frequency of the signals emitted by two mutually detuned pipes with varying distance between the pipes. The spectrum shows a broad '' hump '' structure, not found for coupled oscillators. This indicates a complex coupling of the two organ pipes leading to nonlinear beat phenomena.}, language = {en} } @article{AbelCelaniErgnietal.2002, author = {Abel, Markus and Celani, A. and Ergni, V. and Vulpiani, A.}, title = {Front speed enhancement in cellular flows}, issn = {1054-1500}, year = {2002}, language = {en} } @article{AbelCelaniVergenietal.2001, author = {Abel, Markus and Celani, A. and Vergeni, D. and Vulpiani, A.}, title = {Front propagation in laminar flows}, year = {2001}, abstract = {The Problem of front propagation in flowing media is addressed for laminar velocity fields in two dimensions. Three representative cases are discussed: stationary cellular flow, stationary shear flow, and percolating flow. Production terms of Fisher-Kolmogorov-Petrovskii-Piskunov type and of Arrhenius type are considered under the assumption of no feedback of the concentration on the velocity. Numerical simulations of advection-reaction-diffusion equations have been performed by an algorithm based on discrete-time maps. The results show a generic enhancement of the speed of front propagation by the underlying flow. For small molecular diffusivity, the front speed Vf depends on the typical flow velocity U as a power law with an exponent depending on the topological properties of the flow, and on the ratio of reactive and advective time scales. For open-streamline flows we find always Vf~U, whereas for cellular flows we observe Vf~U1/4 for fast advection and Vf~U3/4 for slow advection.}, language = {en} } @article{AbelFlachPikovskij1998, author = {Abel, Markus and Flach, S. and Pikovskij, Arkadij}, title = {Localisation in a coupled standard map lattice}, year = {1998}, abstract = {We study spatially localized excitations in a lattice of coupled standard maps. Time-periodic solutions (breathers) exist in a range of coupling that is shown to shrink as the period grows to infinity, thus excluding the possibility of time-quasiperiodic breathers. The evolution of initially localized chaotic and quasiperiodic states in a lattice is studied numerically. Chaos is demonstrated to spread}, language = {en} } @article{AbelFlachPikovskij1998, author = {Abel, Markus and Flach, S. and Pikovskij, Arkadij}, title = {Localization in a coupled standard map lattice}, year = {1998}, language = {en} } @book{AbelHolschneider2009, author = {Abel, Markus and Holschneider, Matthias}, title = {Modellierung und Datenbankanalyse komplexer Systeme Teil 2 : Vorlesung 2009-04-23}, publisher = {Univ.-Bibl.}, address = {Potsdam}, year = {2009}, abstract = {Komplexe Systeme reichen von "harten", physikalischen, wie Klimaphysik, Turbulenz in Fluiden oder Plasmen bis zu so genannten "weichen", wie man sie in der Biologie, der Physik weicher Materie, Soziologie oder {\"O}konomie findet. Die Ausbildung von Verst{\"a}ndnis zu einem solchen System beinhaltet eine Beschreibung in Form von Statistiken und schlussendlich mathematischen Gleichungen. Moderne Datenanalyse stellt eine große Menge von Werkzeugen zur Analyse von Komplexit{\"a}t auf verschiedenen Beschreibungsebenen bereit. In diesem Kurs werden statistische Methoden mit einem Schwerpunkt auf dynamischen Systemen diskutiert und einge{\"u}bt. Auf der methodischen Seite werden lineare und nichtlineare Ans{\"a}tze behandelt, inklusive der Standard-Werkzeuge der deskriptiven und schlussfolgernden Statistik, Wavelet Analyse, Nichtparametrische Regression und der Sch{\"a}tzung nichtlinearer Maße wie fraktaler Dimensionen, Entropien und Komplexit{\"a}tsmaßen. Auf der Modellierungsseite werden deterministische und stochastische Systeme, Chaos, Skalierung und das Entstehen von Komplexit{\"a}t durch Wechselwirkung diskutiert - sowohl f{\"u}r diskrete als auch f{\"u}r ausgedehnte Systeme. Die beiden Ans{\"a}tze werden durch Systemanalyse jeweils passender Beispiele vereint.}, language = {de} } @book{AbelHolschneider2009, author = {Abel, Markus and Holschneider, Matthias}, title = {Modellierung und Datenbankanalyse komplexer Systeme Teil 3 : Vorlesung 2009-04-23}, publisher = {Univ.-Bibl.}, address = {Potsdam}, year = {2009}, abstract = {Komplexe Systeme reichen von "harten", physikalischen, wie Klimaphysik, Turbulenz in Fluiden oder Plasmen bis zu so genannten "weichen", wie man sie in der Biologie, der Physik weicher Materie, Soziologie oder {\"O}konomie findet. Die Ausbildung von Verst{\"a}ndnis zu einem solchen System beinhaltet eine Beschreibung in Form von Statistiken und schlussendlich mathematischen Gleichungen. Moderne Datenanalyse stellt eine große Menge von Werkzeugen zur Analyse von Komplexit{\"a}t auf verschiedenen Beschreibungsebenen bereit. In diesem Kurs werden statistische Methoden mit einem Schwerpunkt auf dynamischen Systemen diskutiert und einge{\"u}bt. Auf der methodischen Seite werden lineare und nichtlineare Ans{\"a}tze behandelt, inklusive der Standard-Werkzeuge der deskriptiven und schlussfolgernden Statistik, Wavelet Analyse, Nichtparametrische Regression und der Sch{\"a}tzung nichtlinearer Maße wie fraktaler Dimensionen, Entropien und Komplexit{\"a}tsmaßen. Auf der Modellierungsseite werden deterministische und stochastische Systeme, Chaos, Skalierung und das Entstehen von Komplexit{\"a}t durch Wechselwirkung diskutiert - sowohl f{\"u}r diskrete als auch f{\"u}r ausgedehnte Systeme. Die beiden Ans{\"a}tze werden durch Systemanalyse jeweils passender Beispiele vereint.}, language = {de} } @book{AbelHolschneider2009, author = {Abel, Markus and Holschneider, Matthias}, title = {Modellierung und Datenbankanalyse komplexer Systeme Teil 4 : Vorlesung 2009-04-23}, publisher = {Univ.-Bibl.}, address = {Potsdam}, year = {2009}, abstract = {Komplexe Systeme reichen von "harten", physikalischen, wie Klimaphysik, Turbulenz in Fluiden oder Plasmen bis zu so genannten "weichen", wie man sie in der Biologie, der Physik weicher Materie, Soziologie oder {\"O}konomie findet. Die Ausbildung von Verst{\"a}ndnis zu einem solchen System beinhaltet eine Beschreibung in Form von Statistiken und schlussendlich mathematischen Gleichungen. Moderne Datenanalyse stellt eine große Menge von Werkzeugen zur Analyse von Komplexit{\"a}t auf verschiedenen Beschreibungsebenen bereit. In diesem Kurs werden statistische Methoden mit einem Schwerpunkt auf dynamischen Systemen diskutiert und einge{\"u}bt. Auf der methodischen Seite werden lineare und nichtlineare Ans{\"a}tze behandelt, inklusive der Standard-Werkzeuge der deskriptiven und schlussfolgernden Statistik, Wavelet Analyse, Nichtparametrische Regression und der Sch{\"a}tzung nichtlinearer Maße wie fraktaler Dimensionen, Entropien und Komplexit{\"a}tsmaßen. Auf der Modellierungsseite werden deterministische und stochastische Systeme, Chaos, Skalierung und das Entstehen von Komplexit{\"a}t durch Wechselwirkung diskutiert - sowohl f{\"u}r diskrete als auch f{\"u}r ausgedehnte Systeme. Die beiden Ans{\"a}tze werden durch Systemanalyse jeweils passender Beispiele vereint.}, language = {de} } @book{AbelHolschneider2009, author = {Abel, Markus and Holschneider, Matthias}, title = {Modellierung und Datenbankanalyse komplexer Systeme Teil 5 : Vorlesung 2009-06-04}, publisher = {Univ.-Bibl.}, address = {Potsdam}, year = {2009}, abstract = {Komplexe Systeme reichen von "harten", physikalischen, wie Klimaphysik, Turbulenz in Fluiden oder Plasmen bis zu so genannten "weichen", wie man sie in der Biologie, der Physik weicher Materie, Soziologie oder {\"O}konomie findet. Die Ausbildung von Verst{\"a}ndnis zu einem solchen System beinhaltet eine Beschreibung in Form von Statistiken und schlussendlich mathematischen Gleichungen. Moderne Datenanalyse stellt eine große Menge von Werkzeugen zur Analyse von Komplexit{\"a}t auf verschiedenen Beschreibungsebenen bereit. In diesem Kurs werden statistische Methoden mit einem Schwerpunkt auf dynamischen Systemen diskutiert und einge{\"u}bt. Auf der methodischen Seite werden lineare und nichtlineare Ans{\"a}tze behandelt, inklusive der Standard-Werkzeuge der deskriptiven und schlussfolgernden Statistik, Wavelet Analyse, Nichtparametrische Regression und der Sch{\"a}tzung nichtlinearer Maße wie fraktaler Dimensionen, Entropien und Komplexit{\"a}tsmaßen. Auf der Modellierungsseite werden deterministische und stochastische Systeme, Chaos, Skalierung und das Entstehen von Komplexit{\"a}t durch Wechselwirkung diskutiert - sowohl f{\"u}r diskrete als auch f{\"u}r ausgedehnte Systeme. Die beiden Ans{\"a}tze werden durch Systemanalyse jeweils passender Beispiele vereint.}, language = {de} } @book{AbelHolschneider2009, author = {Abel, Markus and Holschneider, Matthias}, title = {Modellierung und Datenbankanalyse komplexer Systeme Teil 1 : Vorlesung 2009-04-23}, publisher = {Univ.-Bibl.}, address = {Potsdam}, year = {2009}, abstract = {Komplexe Systeme reichen von "harten", physikalischen, wie Klimaphysik, Turbulenz in Fluiden oder Plasmen bis zu so genannten "weichen", wie man sie in der Biologie, der Physik weicher Materie, Soziologie oder {\"O}konomie findet. Die Ausbildung von Verst{\"a}ndnis zu einem solchen System beinhaltet eine Beschreibung in Form von Statistiken und schlussendlich mathematischen Gleichungen. Moderne Datenanalyse stellt eine große Menge von Werkzeugen zur Analyse von Komplexit{\"a}t auf verschiedenen Beschreibungsebenen bereit. In diesem Kurs werden statistische Methoden mit einem Schwerpunkt auf dynamischen Systemen diskutiert und einge{\"u}bt. Auf der methodischen Seite werden lineare und nichtlineare Ans{\"a}tze behandelt, inklusive der Standard-Werkzeuge der deskriptiven und schlussfolgernden Statistik, Wavelet Analyse, Nichtparametrische Regression und der Sch{\"a}tzung nichtlinearer Maße wie fraktaler Dimensionen, Entropien und Komplexit{\"a}tsmaßen. Auf der Modellierungsseite werden deterministische und stochastische Systeme, Chaos, Skalierung und das Entstehen von Komplexit{\"a}t durch Wechselwirkung diskutiert - sowohl f{\"u}r diskrete als auch f{\"u}r ausgedehnte Systeme. Die beiden Ans{\"a}tze werden durch Systemanalyse jeweils passender Beispiele vereint.}, language = {de} } @article{AbelPikovskij1997, author = {Abel, Markus and Pikovskij, Arkadij}, title = {Parametric excitation of breathers in a nonlinear lattice}, year = {1997}, abstract = {We investigate localized periodic solutions (breathers) in a lattice of parametrically driven, nonlinear dissipative oscillators. These breathers are demonstrated to be exponentially localized, with two characteristic localization lengths. The crossover between the two lengths is shown to be related to the transition in the phase of the lattice oscillations.}, language = {en} } @article{AbelSpicci1998, author = {Abel, Markus and Spicci, M.}, title = {Nonlinear localization periodic solutions in a coupled map lattice}, year = {1998}, abstract = {We prove the existence of nonlinear localized time-periodic solutions in a chain of symplectic mappings with nearest neighbour coupling. This is a class of systems whose behaviour can be seen as representation of a lattice of pendula. The effect of discrete time changes the mathematical as well as the numerical procedures. Applying the discrete version of Floquet theory eases and clarifies the procedure of proving the existence of the localized time-periodic solutions. As an extension of the concept of rotobreathers one can produce solutions which rotate at every site of the lattice. To consider these we use a general definition of localization.}, language = {en} } @article{AbelStojkovicBreuer2006, author = {Abel, Markus and Stojkovic, Dragan and Breuer, Michael}, title = {Nonlinear stochastic estimation of wall models for LES}, issn = {0142-727X}, doi = {10.1016/j.heatfluidflow.2005.10.011}, year = {2006}, abstract = {A key technology for large eddy simulation (LES) of complex flows is an appropriate wall modeling strategy. In this paper we apply for the first time a fully nonparametric procedure for the estimation of generalized additive models (GAM) by conditional statistics. As a database, we use DNS and wall-resolved LES data of plane channel flow for Reynolds numbers, Re = 2800, 4000 (DNS) and 10,935, 22,776 (LES). The statistical method applied is a quantitative tool for the identification of important model terms, allowing for an identification of some of the near-wall physics. The results are given as nonparametric functions which cannot be attained by other methods. We investigated a generalized model which includes Schumann's and Piomelli et al.'s model. A strong influence of the pressure gradient in the viscous sublayer is found; for larger wall distances the spanwise pressure gradient even dominates the tau(w,zy). component. The first a posteriori LES results are given.}, language = {en} } @article{AbetzJiangGopfert2004, author = {Abetz, Volker and Jiang, S. M. and Gopfert, A.}, title = {Novel pattern formation in blends of asymmetric ABC triblock terpolymers}, issn = {1618-7229}, year = {2004}, abstract = {A series of polystyrene-block-poly(1,2-butadiene)-block-poly(2-vinyl-pyridine) (SBV) triblock terpolymers were used to prepare blends with symmetric polystyrene-block-poly(2-vinylpyridine) (SV) and poly(2-vinylpyridine)-block-poly- (cyclohexyl methacrylate) (VC) diblock copolymers. Morphological characterization was carried out by transmission electron microscopy. These triblock terpolymers self-assemble into various core-shell type or lamellar morphologies. In the SBV/SV blends, macrophase separation between the two block copolymers, continuous centrosymmetric lamellae and stacks of non-centrosymmetric lamellae with anti-parallel orientation were found. In the blends of SBV/VC, macrophase separation was never observed, what is due to the specific interactions between S and C domains. These systems showed among other morphologies also a cylindrical morphology in which rings surround the cylinders}, language = {en} }