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Neural network learns physical rules for copolymer translocation through amphiphilic barriers

npj Computational Materials 2020年第1期6卷 1039-1046页

作者： marco Werner Yachong Guo Vladimir A.Baulin Institute Theory of Polymers Leibniz-Institut für Polymerforschung Dresden e.V.Hohe Straße 601069 DresdenGermany Departament d’Enginyeria Química Universitat Rovira i Virgili26 Av.dels Paisos Catalans43007 TarragonaSpain Kuang Yaming Honors School Nanjing University22 Hankou Road210093 NanjingChina

Recent developments in computer processing power lead to new paradigms of how problems in many-body physics and especially polymer physics can be *** processors can be exploited to generate millions of molecular configurations in complex environments at a second,and concomitant free-energy landscapes can be *** that are complete in terms of polymer sequences and architecture form a powerful training basis for cross-checking and verifying machine learning-based *** employ an exhaustive enumeration of polymer sequence space to benchmark the prediction made by a neural *** our example,we consider the translocation time of a copolymer through a lipid membrane as a function of its sequence of hydrophilic and hydrophobic ***,we demonstrate that massively parallel Rosenbluth sampling for all possible sequences of a polymer allows for meaningful dynamic interpretation in terms of the mean first escape times through the ***,we train a multi-layer neural network on logarithmic translocation times and show by the reduction of the training set to a narrow window of translocation times that the neural network develops an internal representation of the physical rules for sequencecontrolled diffusion *** on the narrow training set,the network result approximates the order of magnitude of translocation times in a window that is several orders of magnitude wider than the training *** investigate how prediction accuracy depends on the distance of unexplored sequences from the training window.

关键词： neural network narrow

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Photorealistic modelling of metals from first principles

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npj Computational Materials 2019年第1期5卷 1-12页

作者： Gianluca Prandini Gian-marco Rignanese Nicola Marzari Theory and Simulation of Materials(THEOS)and National Centre for Computational Design and Discovery of Novel Materials(MARVEL) École Polytechnique Fédérale de Lausanne1015 LausanneSwitzerland Institute of Condensed Matter and Nanosciences(IMCN) Universitécatholique de Louivain1348 Louvain-la-NeuveBelgium

The colours of metals have attracted the attention of humanity since ancient times,and coloured metals,in particular gold compounds,have been employed for tools and objects symbolizing the aesthetics of *** this work,we develop a comprehensive framework to obtain the reflectivity and colour of metals,and show that the trends in optical properties and the colours can be predicted by straightforward first-principles techniques based on standard *** apply this to predict reflectivity and colour of several elemental metals and of different types of metallic compounds(intermetallics,solid solutions and heterogeneous alloys),considering mainly binary alloys based on noble *** validate the numerical approach through an extensive comparison with experimental data and the photorealistic rendering of known coloured metals.

关键词： alloys intermetallics metals

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Coordination corrected ab initio formation enthalpies

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npj Computational Materials 2019年第1期5卷 633-644页

作者： Rico friedrich Demet Usanmaz Corey Oses Andrew Supka marco fornari marco Buongiorno Nardelli Cormac Toher Stefano Curtarolo Department of Mechanical Engineering and Materials Science Duke UniversityDurhamNC 27708USA Center for Materials Genomics Duke UniversityDurhamNC 27708USA Department of Physics and Science of Advanced Materials Program Central Michigan UniversityMount PleasantMI 48859USA Department of Physics and Department of Chemistry University of North TexasDentonTX 76203USA Materials Science Electrical EngineeringPhysics and ChemistryDuke UniversityDurhamNC 27708USA fritz-Haber-Institut der Max-Planck-Gesellschaft 14195 Berlin-DahlemGermany

The correct calculation of formation enthalpy is one of the enablers of ab-initio computational materials *** several classes of systems(***)standard density functional theory produces incorrect *** we propose the“coordination corrected enthalpies”method(CCE),based on the number of nearest neighbor cation–anion bonds,and also capable of correcting relative stability of *** uses calculations employing the Perdew,Burke and Ernzerhof(PBE),local density approximation(LDA)and strongly constrained and appropriately normed(SCAN)exchange correlation functionals,in conjunction with a quasiharmonic Debye model to treat zero-point vibrational and thermal *** benchmark,performed on binary and ternary oxides(halides),shows very accurate room temperature results for all functionals,with the smallest mean absolute error of 27(24)meV/atom obtained with *** zero-point vibrational and thermal contributions to the formation enthalpies are small and with different signs—largely canceling each other.

关键词： corrected vibrational oxides

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Materials property prediction for limited datasets enabled by feature selection and joint learning with MODNet

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npj Computational Materials 2021年第1期7卷 731-738页

作者： Pierre-Paul De Breuck Geoffroy Hautier Gian-marco Rignanese UCLouvain Institute of Condensed Matter and Nanosciences(IMCN)Louvain-la-NeuveBelgium Dartmouth College Thayer School of EngineeringHanoverNHUSA

In order to make accurate predictions of material properties,current machine-learning approaches generally require large amounts of data,which are often not available in *** this work,MODNet,an all-round framework,is presented which relies on a feedforward neural network,the selection of physically meaningful features,and when applicable,*** to being faster in terms of training time,this approach is shown to outperform current graph-network models on small *** particular,the vibrational entropy at 305 K of crystals is predicted with a mean absolute test error of 0.009 meV/K/atom(four times lower than previous studies).furthermore,joint learning reduces the test error compared to single-target learning and enables the prediction of multiple properties at once,such as temperature ***,the selection algorithm highlights the most important features and thus helps to understand the underlying physics.

关键词： learning prediction property

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A unified field theory of topological defects and non-linear local excitations

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npj Computational Materials 2023年第1期9卷 1092-1104页

作者： Vidar Skogvoll Jonas Rønning marco Salvalaglio Luiza Angheluta PoreLab Njord CentreDepartment of PhysicsUniversity of OsloP.O.Box 10480316 OsloNorway Institute of Scientific Computing TU Dresden01062 DresdenGermany Dresden Center for Computational Materials Science TU Dresden01062 DresdenGermany

Topological defects and smooth excitations determine the properties of systems showing collective *** introduce a generic non-singular field theory that comprehensively describes defects and excitations in systems with O(n)broken rotational *** this formalism,we explore fast events,such as defect nucleation/annihilation and dynamical phase transitions where the interplay between topological defects and non-linear excitations is particularly *** highlight its versatility,we apply this formalism in the context of Bose-Einstein condensates,active nematics,and crystal lattices.

关键词： excitation topological theory

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Application of UV depth lithography in micro system technology

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Optoelectronics Letters 2008年第1期4卷 1-4页

作者： Stephanus Büttgenbach marco feldmann Institute for Microtechnology Technical University of Braunschweig Langer Kamp 8 38106 Braunschweig Germany

This letter reports on new types of photo resists allowing UV-light exposure of thick layers. Optimized processes Cthat for the positive resist AZ 9260 and the negative resist Epon SU-8 have been developed enabling the fabrication of high aspect ratio metallic and polymer micro components. The high potential of this technology will be demonstrated on the basis of two examples, a variable reluctance micro motor with compensated attractive force and an optical microphone developed for application in electro-magnetic interference environments.

关键词：微系统技术紫外线平版印刷术微电子学

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Modeling of the 3D spatio-temporal thermal profile of joule-class Yb3+-based laser amplifiers

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High Power Laser Science and Engineering 2019年第3期7卷 53-59页

作者： Issa Tamer Sebastian Keppler Jorg Komer marco Hornung marco Hellwing frank Schorcht Joachim Hein Malte C.Kaluza Helmholtz-Institute Jena Frobelstieg 307743 JenaGermany friedrich-Schiller-University Jena Max-Wien Platz 107743 JenaGermany

Thermal profile modification of an active material in a laser amplifier via optical pumping results in a change in the material’s refractive index,and causes thermal expansion and stress,eventually leading to spatial phase aberrations,or even permanent material *** this purpose,knowledge of the 3D spatio-temporal thermal profile,which can currently only be retrieved via numerical simulations,is critical for joule-class laser amplifiers to reveal potentially dangerous thermal features within the pumped active *** this investigation,a detailed,spatio-temporal numerical simulation was constructed and tested for accuracy against surface thermal measurements of various endpumped Yb^3+-doped laser-active *** measurements and simulations show an excellent agreement and the model was successfully applied to a joule-class Yb3+-based amplifier currently operating in the POLARIS laser system at the friedrich-Schiller-University and Helmholtz-Institute Jena in Germany.

关键词： diode-pumped solid-state lasers high intensity lasers laser amplifiers spatio-temporal thermal profile modeling ytterbium

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Mitigation of spectral leakage for single carrier, block-processing cognitive radio receivers

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Digital Communications and Networks 2018年第2期4卷 106-110页

作者： Adam C. Polak Mark Wagner marco f. Duarte Robert W. Jackson Dennis L. Goeckel Electrical and Computer Engineering Department University of Massachusetts Amherst United States

Cognitive Radio （CR） is a multiuser, wireless communication concept that allows for a dynamic and adaptive assignment of spectral resources. The coexistence of multiple users, often transmitting at significantly different power levels, makes CR receivers vulnerable to spectral leakage caused by components＇ nonlinearities and timetruncation of the processed signal records. In this work we propose a method for mitigating the latter with an adaptive choice of the length of the processing block size. With simulations we show that a significant leakage reduction that leads to receiver dynamic range improvement of around 10 dB can be achieved with the proposed method.

关键词： Spectral leakage Dynamic range Single carrier block transmission Interference White space Cognitive radio

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Geometrical approach for an optimal inter-satellite visibility

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Astrodynamics 2021年第3期5卷 237-248页

作者： marco Cinelli Emiliano Ortore Giovanni Laneve Christian Circi Department of Mathematics University of Rome Tor VergataRome 00133Italy Department of Astronautical Electrical and Energy EngineeringSapienza University of RomeRome 00138Italy Scuola di Ingegneria Aerospaziale Sapienza University of RomeRome 00138Italy

In the eld of satellite constellations,an important requirement is often represented by the possibility to exchange data among the satellites or exploit mutual visibility to carry out measurements on the parameters of the Earth's ***,recursive and routing algorithms are usually implemented to evaluate inter-satellite visibility ***,to design the con guration of the constellation,it is important to consider the orbital conditions that guarantee the mutual visibility between couples of ***,in this study,a geometric analysis was performed to identify the optimal inter-satellite visibility conditions,expressed in terms of the di erence in the true anomaly between satellites characterized by di erent orbital con *** approach allows a handy constellation design,without performing a numerical *** is particularly useful in the case of a high number of satellites,when numerical techniques require signi cant computational e ***,it is possible to considerably simplify the design of a constellation in which the mutual visibility between couples of satellites is always *** type of constellation,usually referred to as satellite chain,can be exploited in several network services and remote sensing systems devoted to enhancing the knowledge of atmospheric parameters.

关键词： satellite constellation interlink visibility

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Connector theory for reusing model results to determine materials properties

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npj Computational Materials 2022年第1期8卷 923-930页

作者： marco Vanzini Ayoub Aouina Martin Panholzer Matteo Gatti Lucia Reining LSI CNRSCEA/DRF/IRAMISÉcole PolytechniqueInstitut Polytechnique de ParisF-91120PalaiseauFrance Theory and Simulation of Materials(THEOS) École Polytechnique Fédérale de LausanneCH-1015LausanneSwitzerland European Theoretical Spectroscopy facility(ETSf)https://www.etsf.eu Johannes Kepler University Linz LinzAustria Uni Software Plus GmbH Linzer Strasse 64320PergAustria Synchrotron SOLEIL L’Orme des MerisiersSaint-AubinBP 48F-91192Gif-sur-YvetteFrance

The success of Density functional Theory(DfT)is partly due to that of simple approximations,such as the Local Density Approximation(LDA),which uses results of a model,the homogeneous electron gas,to simulate exchange-correlation effects in real *** turn this intuitive approximation into a general and in principle exact theory by introducing the concept of a connector:a prescription how to use results of a model system in order to simulate a given quantity in a real *** this framework,the LDA can be understood as one particular approximation for a connector that is designed to link the exchange-correlation potentials in the real material to that of the *** the in principle exact connector equations allows us to go beyond the LDA in a systematic ***,connector theory is not bound to DfT,and it suggests approximations also for other functionals and other *** explain why this very general approach is indeed a convenient starting point for *** illustrate our purposes with simple but pertinent examples.

关键词： materials theory exact

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