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应用激光 1980年第4期 43-45页

作者： p.W.Smith j.p.hermann W.j.Tomlinson p.j.Maloney 范元绚法国综合工科学校量子光学实验室法国综合工科学校量子光学实验室美国贝尔实验室美国贝尔实验室

在某些情况下,在一线性介质和一非线性（克尔效应）介质的界面上,反射系数随光强的变化会表现出滞后效应。我们用～1ns 的红宝石激光脉冲入射到玻璃-CS2界面上进行了实验,首次对这种滞后效应作了实验验证。本文介绍了这一实验结果。

关键词：非线性介质光强红宝石激光反射系数入射光脉冲波形

A discrete contact model for complex arbitrary-shaped convex geometries

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particuology 2023年第9期80卷 180-191页

作者： jan E.Marquardt Ulrich j.Römer hermann Nirschl Mathias j.Krause Lattice Boltzmann Research Group Karlsruhe Institute of TechnologyStraße am Forum 8Karlsruhe76131Germany Institute for Mechanical process Engineering and Mechanics Karlsruhe Institute of TechnologyStraße am Forum 8Karlsruhe76131Germany Institute of Engineering Mechanics Karlsruhe Institute of TechnologyKaiserstraße 10Karlsruhe76131Germany Institute for Applied and Numerical Mathematics Karlsruhe Institute of TechnologyEnglerstraße 2Karlsruhe76131Germany

The shape of particles has a significant influence on the behavior of suspensions,as the particle-fluid,particle-particle,and particle-wall interactions depend on ***,the simultaneous consideration of complex particle shapes and four-way coupling remains a major *** is mainly due to a lack of suitable contact *** models for complex shapes have been proposed in literature,and most limit the accuracy of the particle-fluid *** this reason,this paper presents a novel contact model for complex convex particle shapes for use with partially saturated methods,in which we propose to obtain necessary contact properties,such as the indentation depth,by a discretization of the contact *** goal of the proposed model is to enable comprehensive and accurate studies of particulate flows,especially with high volume fractions,that lead to new insights and contribute to the improvement of existing industrial *** ensure correctness and sustainability,we validate the model extensively by studying cases with and without *** the latter case,we use the homogenized lattice Boltzmann *** provided investigations show a great agreement of the proposed discrete contact model with analytical solutions and the literature.

关键词： partially saturated cells method Homogenized lattice Boltzmann method Arbitrarily shaped particle Discrete contact model particle-resolved simulation OpenLB

particle flow simulations with homogenised lattice Boltzmann methods

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particuology 2017年第5期15卷 1-13页

作者： Mathias j. Krause Fabian Klemens Thomas Henn Robin Trunk hermann Nirschl Institute for Applied and Numerical Mathematics Karlsruhe Institute of Technology 76021 Karlsruhe Germany Institute for Mechanical process Engineering and Mechanics Karlsruhe Institute of Technology 76021 Karlsruhe Germany

An alternative approach to simulating arbitrarily shaped particles submersed in viscous fluid in two dimensions is proposed, obtained by adapting the velocity parameter of the equilibrium distribution function of a standard lattice Boltzmann method （LBM）. Comparisons of exemplifying simulations to results in the literature validate the approach as well as the convergence analysis. pressure fluctuations occurring in Ladd＇s approach are greatly reduced. In comparison with the immersed boundary method, this approach does not require cost intensive interpolations. The parallel efficiency of LBM is retained. An intrinsic momentum transfer is observed during particle-particle collisions. To demonstrate the capa- bilities of the approach, sedimentation of particles of several shapes is simulated despite omitting an explicit particle collision model.

关键词： particulate flow simulationsArbitrarily shaped particlesLattice Boltzmann methodsValidationSedimentation processes

Apoptosis induced by titanium dioxide nanoparticles in cultured murine microglia N9 cells

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Chinese Science Bulletin 2009年第20期54卷 3830-3836页

作者： LI XiaoBo XU ShunQing ZHANG ZhiRen hermann j Schluesener School of public Health Southeast University Nanjing 210009 China Key Laboratory of Environment and Heath of the Ministry of Education Institute of Environmental Medicine School of Public Health Tongji Medical College Huazhong University of Science and Technology Wuhan 430030 China Institute of Brain Research University of Tuebingen Calwer Str. 3 D-72076 Tuebingen Germany

Owing to the rapidly increasing output of nano-scale titanium dioxide(TiO2) particles,their potential risk for central nerve system(CNS) has elicited much concern *** is the resident macrophage in CNS and essential for the homeostasis of the CNS *** are supposed to response to nanoparticles depositing in the brain ***,we investigated the cytotoxic effects of TiO2 Nps on microglia N9 cells in *** of propidium iodide/fluorescein diacetate(pI/FDA) double staining and MTT test clearly showed that TiO2 Nps more efficiently affected the viability of microglia N9 *** Hoechst 33258 staining and flow cytometric analysis proved that nano-scale but not normal scale TiO2 induced apoptosis in *** data suggest that TiO2 Nps can elicit apoptosis of N9 cells in vitro and thus present a potential risk for CNS.

关键词：纳米二氧化钛胶质细胞细胞凋亡诱导培养中枢神经系统二氧化钛纳米粒流式细胞仪分析小鼠

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Assessing risks and uncertainties in forest dynamics under different management scenarios and climate change

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Forest Ecosystems 2015年第3期2卷 169-189页

作者： Matthias Albert jan Hansen jürgen Nagel Matthias Schmidt hermann Spellmann Northwest German Forest Research Station

Background: Forest management faces a climate induced shift in growth potential and increasing current and emerging new risks. Vulnerability analysis provides decision support based on projections of natural resources taking risks and uncertainties into account. In this paper we(1) characterize differences in forest dynamics under three management scenarios,(2) analyse the effects of the three scenarios on two risk factors, windthrow and drought stress, and(3) quantify the effects and the amount of uncertainty arising from climate projections on height increment and drought ***: In four regions in northern Germany, we apply three contrasting management scenarios and project forest development under climate change until 2070. Three climate runs(minimum, median, maximum) based on the emission scenario RCp 8.5 control the site-sensitive forest growth functions. The minimum and maximum climate run define the range of prospective climate ***: The projections of different management regimes until 2070 show the diverging medium-term effects of thinnings and harvests and long-term effects of species conversion on a regional scale. Examples of windthrow vulnerability and drought stress reveal how adaptation measures depend on the applied management path and the decision-maker’s risk attitude. Uncertainty analysis shows the increasing variability of drought risk projections with time. The effect of climate projections on height growth are quantified and uncertainty analysis reveals that height growth of young trees is dominated by the age-trend whereas the climate signal in height increment of older trees is ***: Drought risk is a serious issue in the eastern regions independent of the applied silvicultural scenario,but adaptation measures are limited as the proportion of the most drought tolerant species Scots pine is already high. Windthrow risk is no serious overall threat in any region, but adequate counter-measures such as spec

关键词： Climate change Silvicultural management strategies

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Coexistence of plastic and partially diffusive phases in a helium-methane compound

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National Science Review 2020年第10期7卷 1540-1547页

作者： Hao Gao Cong Liu Andreas hermann Richard j.Needs Chris j.pickard Hui-Tian Wang Dingyu Xing jian Sun National Laboratory of Solid State Microstructures School of Physics and Collaborative Innovation Center of Advanced MicrostructuresNanjing University Centre for Science at Extreme Conditions and The School of physics and Astronomy The University of Edinburgh Theory of Condensed Matter Group Cavendish Laboratory Department of Materials Science & Metallurgy University of Cambridge Advanced Institute for Materials Research Tohoku University

Helium and methane are major components of giant icy planets and are abundant in the universe. However,helium is the most inert element in the periodic table and methane is one of the most hydrophobic molecules, thus whether they can react with each other is of fundamental importance. Here, our crystal structure searches and first-principles calculations predict that a He;CH;compound is stable over a wide range of pressures from 55 to 155 Gpa and a HeCH;compound becomes stable around 105 Gpa. As nice examples of pure van der Waals crystals, the insertion of helium atoms changes the original packing of pure methane molecules and also largely hinders the polymerization of methane at higher pressures. After analyzing the diffusive properties during the melting of He;CH;at high pressure and high temperature, in addition to a plastic methane phase, we have discovered an unusual phase which exhibits coexistence of diffusive helium and plastic methane. In addition, the range of the diffusive behavior within the helium-methane phase diagram is found to be much narrower compared to that of previously predicted helium-water compounds. This may be due to the weaker van der Waals interactions between methane molecules compared to those in helium-water compounds, and that the helium-methane compound melts more easily.

关键词： crystal structure prediction ab initio molecular dynamics ab initio calculations high pressure and high temperature melting and phase transition collective motion

Complex RNA-DNA hybrid nanoshapes from iterative mix-andmatch screening

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Nano Research 2021年第1期14卷 46-51页

作者： Shi Chen Zhiyuan Zhang Eugene Alforque Thomas hermann Department of Chemistry and Biochemistry University of CaliforniaSan DiegoCA 92093USA Center for Drug Discovery Innovation University of CaliforniaSan DiegoCA 92093USA Materials Science and Engineering program University of CaliforniaSan DiegoCA 92093USA

Hybrid nucleic acid nanostructures partition architectural and functional roles between ribonucleic acid(RNA)joints and deoxyribonucleic acid(DNA)*** self-assemble from nucleic acid modules through synergistic stabilization of marginally stable base pairing interactions within circularly closed ***,we report the development of hybrid nanoshapes that include multiple different RNA modules such as internal loop and three-way junction(3Wj)*** iterative mix-and-match screening approach was used to identify suitable DNA connectors that furnished stable nanoshapes for combinations of different RNA *** resulting complex multicomponent RNA-DNA hybrid nanoshapes were characterized by atomic force microscopy(AFM)*** research provides proof of concept for modular design,assembly and screening of RNA-DNA hybrid nanoshapes as building blocks for complex extended nucleic acid materials with features at the sub-10 nm scale.

关键词： nucleic acid nanotechnology nanoshapes ribonucleic acid(RNA)three-way junction(3Wj) RNA deoxyribonucleic acid(DNA) sub-10 nm features

Enhanced photoluminescence of a microporous quantum dot color conversion layer by inkjet printing

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Nano Research 2024年第8期17卷 7717-7725页

作者： junchi Chen Qihao jin Yidenekachew.j.Donie Orlando.T.perales Dmitry Busko Bryce.S.Richards Uli Lemmer Light Technology Institute(LTI) Karlsruhe Institute of Technology(KIT)Engesserstrasse 1376131 KarlsruheGermany Department of Chemical Engineering and Materials Science University of Minnesota(UMN)421 Washington Ave.SEMinneapolisMN 55455-0132USA Institute for Microstructure Technology Karlsruhe Institute of Technology(KIT)Hermann-von-Helmholtz-Platz 176344 Eggenstein-LeopoldshafenGermany

Owing to their high color purity,tunable bandgap,and high efficiency,quantum dots(QDs)have gained significant attention as color conversion materials for high-end display ***,inkjet-printed QD pixels show great potential for realizing full-color mini/micro-light emitting diode(micro-LED)-based *** a color conversion layer,the photoluminescence intensity of QDs is limited by the insufficient absorptance of the excitation light due to the lack of *** scatterers,such as titanium dioxide microparticles,have been applied after additional surface engineering for sufficient dispersity to prevent nozzle clogging in inkjet printing *** our work,as an alternative approach,we use inkjet printing for depositing a phase separating polymer ink based on polystyrene(pS)and polyethylene glycol(pEG).QD/polymer composite pixels with scattering micropores are *** morphology of the micropores can be tailored by the weight ratio between pS and pEG which enables the manipulation of scattering *** the presence of the microporous structure,the photoluminescence intensity of the QD film is enhanced by 110%in drop-cast films and by 35.3%in inkjet-printed QD pixel arrays compared to the reference samples.

关键词： porous structure inkjet printing phase separation quantum dots display technology

Deep Bayesian local crystallography

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npj Computational Materials 2021年第1期7卷 1649-1660页

作者： Sergei V.Kalinin Mark p.Oxley Mani Valleti junjie Zhang Raphael p.hermann Hong Zheng Wenrui Zhang Gyula Eres Rama K.Vasudevan Maxim Ziatdinov Center for Nanophase Materials Sciences Oak Ridge National LaboratoryOak RidgeTN 37831USA Bredesen Center for Interdisciplinary Research The University of TennesseeKnoxvilleTN 37996USA Materials Science and Technology Division Oak Ridge National LaboratoryOak RidgeTN 37831USA Materials Science Division Argonne National LaboratoryArgonneIL 60439USA Computational Sciences and Engineering Division Oak Ridge National LaboratoryOak RidgeTN 37831USA present address:State Key Laboratory of Crystal Materials&Institute of Crystal Materials Shandong UniversityJinanShandong 250100China

The advent of high-resolution electron and scanning probe microscopy imaging has opened the floodgates for acquiring atomically resolved images of bulk materials,2D materials,and *** plethora of data contains an immense volume of information on materials structures,structural distortions,and physical *** this knowledge regarding local physical phenomena necessitates the development of the mathematical frameworks for extraction of relevant ***,the analysis of atomically resolved images is often based on the adaptation of concepts from macroscopic physics,notably translational and point group symmetries and symmetry lowering ***,we explore the bottom-up definition of structural units and symmetry in atomically resolved data using a Bayesian *** demonstrate the need for a Bayesian definition of symmetry using a simple toy model and demonstrate how this definition can be extended to the experimental data using deep learning networks in a Bayesian setting,namely rotationally invariant variational autoencoders.

关键词： symmetry local resolved

Design of Two-phase Inductor Circuit for the Floating-Zone Crystal Growth

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journal of Iron and Steel Research International 2012年第S2期19卷 700-704页

作者： j.priede G Gerbeth R.hermann Applied Mathematics Research Centre Coventry University Helmholtz-Zentrum Dresden-Rossendorf Leibniz Institute of Solid State and Materials Research

The present work is concerned with the growth of small-diameter single intermetallic compound crystals by the floating-zone method using a radio frequency(RF)induction *** order to maintain a convex solidification interface,which is required for the growth of single crystals,we have developed a novel two-phase inductor comprising a secondary coil,which is short-circuited through capacitor and *** former is adjusted to have resonance in the secondary circuit,which results in a 90 degrees phase lag of the secondary current relative to the primary ***, it is not always possible to tune the secondary circuit into the resonance as it turns out to be incompatible with the operation of contemporary self-tuning *** show that the resonance frequency is unstable unless the resistance of the secondary circuit is made high *** results are confirmed by both numerical simulation of the circuit system using the Simulink and measurements on the floating-zone crystal growth facility equipped with a two-phase inductor.

关键词： floating-zone technique induction heating

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