检索结果-南通市图书馆

Linking electronic structure calculations to generalized stacking fault energies in multicomponent alloys

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

npj Computational Materials 2020年第1期6卷 989-997页

作者： Anirudh Raju Natarajan anton van der ven Materials Department University of CaliforniaSanta BarbaraCA 93106USA

The generalized stacking fault energy is a key ingredient to mesoscale models of dislocations.Here we develop an approach to quantify the dependence of generalized stacking fault energies on the degree of chemical disorder in multicomponent alloys.We introduce the notion of a“configurationally-resolved planar fault”(CRPF)energy and extend the cluster expansion method from alloy theory to express the CRPF as a function of chemical occupation variables of sites surrounding the fault.We apply the approach to explore the composition and temperature dependence of the unstable stacking fault energy(USF)in binary Mo–Nb alloys.First-principles calculations are used to parameterize a formation energy and CRPF cluster expansion.Monte Carlo simulations show that the distribution of USF energies is significantly affected by chemical composition and temperature.The formalism is broadly applicable to arbitrary crystal structures and alloy chemistries and will enable the development of rigorous models for deformation mechanisms in high-entropy alloys.

关键词： alloy alloys fault

Mechanochemical spinodal decomposition: a phenomenological theory of phase transformations in multi-component, crystalline solids

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

npj Computational Materials 2016年第1期2卷 133-141页

作者： Shiva Rudraraju anton van der ven Krishna Garikipati Department of Mechanical Engineering University of MichiganAnn ArborMIUSA Materials Department University of CaliforniaSanta BarbaraCAUSA Department of Mathematics University of MichiganAnn ArborMIUSA

We present a phenomenological treatment of diffusion-driven martensitic phase transformations in multi-component crystalline solids that arise from non-convex free energies in mechanical and chemical variables.The treatment describes diffusional phase transformations that are accompanied by symmetry-breaking structural changes of the crystal unit cell and reveals the importance of a mechanochemical spinodal,defined as the region in strain–composition space,where the free-energy density function is non-convex.The approach is relevant to phase transformations wherein the structural order parameters can be expressed as linear combinations of strains relative to a high-symmetry reference crystal.The governing equations describing mechanochemical spinodal decomposition are variationally derived from a free-energy density function that accounts for interfacial energy via gradients of the rapidly varying strain and composition fields.A robust computational framework for treating the coupled,higher-order diffusion and nonlinear strain gradient elasticity problems is presented.Because the local strains in an inhomogeneous,transforming microstructure can be finite,the elasticity problem must account for geometric nonlinearity.An evaluation of available experimental phase diagrams and first-principles free energies suggests that mechanochemical spinodal decomposition should occur in metal hydrides such as ZrH_(2−2c).The rich physics that ensues is explored in several numerical examples in two and three dimensions,and the relevance of the mechanism is discussed in the context of important electrode materials for Li-ion batteries and high-temperature ceramics.

关键词： microstructure phase chemical

Comparing crystal structures with symmetry and geometry

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

npj Computational Materials 2021年第1期7卷 1491-1501页

作者： John C.Thomas Anirudh Raju Natarajan anton van der ven Materials Department University of CaliforniaSanta BarbaraCAUSA

Measuring the similarity between two arbitrary crystal structures is a common challenge in crystallography and materials science.Although there are an infinite number of ways to mathematically relate two crystal structures,only a few are physically meaningful.Here we introduce both a geometry-based and a symmetry-adapted similarity metric to compare crystal structures.Using crystal symmetry and combinatorial optimization we describe an algorithm to arrive at the structural relationship that minimizes these similarity metrics across all possible maps between any pair of crystal structures.The approach makes it possible to(i)identify pairs of crystal structures that are identical,(ii)quantitatively measure the similarity between crystal structures,and(iii)find and rank structural transformation pathways between any pair of crystal structures.We discuss the advantages of using the symmetryadapted cost metric over the geometric cost.Finally,we show that all known structural transformation pathways between common crystal structures are recovered with the mapping algorithm.The methodology presented in this study will be of value to efforts that seek to catalogue crystal structures,identify structural transformation pathways or prune large first-principles datasets used to parameterize on-lattice Hamiltonians.

关键词： crystal symmetry similarity

Pt-CaTiO3在氧化还原条件下热力学性质的理论研究

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Pt-CaTiO3在氧化还原条件下热力学性质的理论研究

Exploring water and ion transport process at silicone/copper interfaces using in-situ electrochemical and Kelvin probe approaches

中国化学会第28届学术年会

作者：李白海陈亮 anton van der ven 潘晓晴中国科学院宁波材料技术与工程研究所 Department of Materials Science and Engineering University of MichiganAnn Arbor48109

＜正＞钙钛矿基汽车尾气"智能催化剂"引起了人们极大兴趣。[1,2]但人们对该体系（例如Pt-CaTiO3）中贵金属与载体之间的相互作用知之甚少。我们采用第一性原理与热力学研究相结合分析该体系在不同条件下的相平衡以及热力学变化过程,以... 详细信息

＜正＞钙钛矿基汽车尾气"智能催化剂"引起了人们极大兴趣。[1,2]但人们对该体系（例如Pt-CaTiO3）中贵金属与载体之间的相互作用知之甚少。我们采用第一性原理与热力学研究相结合分析该体系在不同条件下的相平衡以及热力学变化过程,以达到对该体系深入的认识并指导实验设计出更有效的"智能催化剂"。

关键词：钙钛矿催化剂相图

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2021年第5期64卷 203-213页

作者： B.Munirathinam J.P.B.van Dam A.Herrmann W.D.van Driel F.De Buyl S.J.F.Erich L.G.J.van der ven O.C.G.Adan J.M.C.Mol Delft University of Technology Department of Materials Science and Engineering DepartmentDelftThe Netherlands Eindhoven University of Technology Department of Applied PhysicsEindhovenThe Netherlands Signify High Tech CampusEindhovenThe Netherlands Delft University of Technology Electronic ComponentsTechnology and MaterialsFaculty of Electrical EngineeringDelftThe Netherlands Dow Silicones Belgium s.p.r.l. Belgium

In general,packaging materials which encapsulate light emitting diodes(LEDs)and microelectronic devices offer barrier protection against several environmental hazards such as water and ionic contaminants.However,these encapsulants may provide pathways for water and ionic contaminants to reach the metal/polymer interfaces and provoke local corrosion of electronics,which is a major reliability concern for polymer encapsulated LEDs and microelectronics.As the water and corrosive constituents play a crucial role in their reliability,water uptake kinetics,interfacial ion transport and delamination behaviour of silicone coated copper model system,mimicking a typical microelectronics packaging system,is explored in the present work.Electrochemical impedance spectroscopy(EIS)integrated with attenuated total reflection Fourier transform infrared(ATR-FTIR)spectroscopy studies revealed that water diffusion inside the silicone network is Fickian in nature and the evolution of the observed time constants are related to the diffusion and interfacial reactions.A decrease of impedance magnitude with time was observed in EIS measurements concurrently with water absorption bands shifting towards lower wavenumber in ATR-FTIR measurements,implying the growth of strong hydrogen bonding between water molecules and the silicone network.The estimated diffusion constant of water using the capacitance method was in the order of 7×10^(-12)m^(2)s^(-1)and the water absorption volume fraction was in the range of 0%to 0.30%.Scanning Kelvin probe studies elucidated the ion transport process occurring at the silicone/copper interface in a humid atmosphere.The interfacial ion transport process is controlled by the interfacial electrochemical reactions at the cathodic delamination front and the estimated average delamination rate is 0.43 mm h^(-1/2).This work demonstrates that exploring ion and water transport in the silicone coating and along the silicone/copper interface is of pivotal importance as part of a detailed reliability assessment of th

关键词： Silicone Impedance Water transport Scanning Kelvin probe Delamination

Reaction injection molding of hydrophilicin-hydrophobic femtolitre-well arrays

在线全文

学校读者我要写书评

暂无评论

Microsystems & Nanoengineering 2019年第1期5卷 429-435页

作者： Reza Zandi Shafagh Deborah Decrop Karen ven Arno vanderbeke Robert Hanusa Jolien Breukers Gaspard Pardon Tommy Haraldsson Jeroen Lammertyn Wouter van der Wijngaart Department of Micro-and Nanosystems KTH Royal Institute of TechnologyStockholmSweden Department of Biosystems KU LeuvenWillem de Croylaan 423001 LeuvenBelgium

Patterning of micro-and nanoscale topologies and surface properties of polymer devices is of particular importance for a broad range of life science applications,including cell-adhesion assays and highly sensitive bioassays.The manufacturing of such devices necessitates cumbersome multiple-step fabrication procedures and results in surface properties which degrade over time.This critically hinders their wide-spread dissemination.Here,we simultaneously mold and surface energy pattern microstructures in off-stoichiometric thiol-ene by area-selective monomer selfassembly in a rapid micro-reaction injection molding cycle.We replicated arrays of 1,843,650 hydrophilic-inhydrophobic femtolitre-wells with long-term stable surface properties and magnetically trapped beads with 75%and 87.2%efficiency in single-and multiple-seeding events,respectively.These results form the basis for ultrasensitive digital biosensors,specifically,and for the fabrication of medical devices and life science research tools,generally.

关键词： arrays hinder beads

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

可调整精度在SMT产量优化中的作用

电子工业专用设备 2003年第6期32卷 30-31页

作者： Jan van der ven 安必昂(Assembleon)香港公司

大多数SMT贴装机均有专门的精度规格,生产线由一系列能满足所贴装元件精度要求的机器组成.但生产线上各种机器混合,有时甚至来自不同设备供应商的机器,都给生产线带来了设置、运作以及维护的开支.如果所有的贴装操作都能在单个平台上实... 详细信息

大多数SMT贴装机均有专门的精度规格,生产线由一系列能满足所贴装元件精度要求的机器组成.但生产线上各种机器混合,有时甚至来自不同设备供应商的机器,都给生产线带来了设置、运作以及维护的开支.如果所有的贴装操作都能在单个平台上实现,制造商将能获得最佳的生产效率.

关键词：产量优化开支设备供应商生产量制造商运作生产效率 SMT贴装 SMT 元件

在线全文

学校读者我要写书评

暂无评论

中国物流业的缺憾

市场与电脑 2001年第5期 25-26页

作者： Hendrik ven der ZWEEP

乳腺扩散光学断层成像:一种新的成像方法的初步应用及其与磁共振成像的比较

在线全文

学校读者我要写书评

暂无评论

国际医学放射学杂志 2009年第4期32卷 401-402页

作者： S.M.W.Y. van de ven S.G. Elias A.J. Wiethoff M. van der Voort T. Nielsen B. Brendel 冯长超（译）李威（校） Department of Radiology University Medical Center Utrecht E.01.132 Heidelberglaau 100 P.O. Box 85500 3508 GA Utrecht The Netherlands. 不详

本研究对新型乳腺扩散光学断层成像（diffuse optical tomography,DOT）系统进行评估。使用DOT和MRI评估17例女性病人的18个乳腺病变（10个侵袭性癌．2个纤维腺瘤和6个良性囊肿；直径13～55mm）。在最初36例入选病人中一部分因技术问题... 详细信息

本研究对新型乳腺扩散光学断层成像（diffuse optical tomography,DOT）系统进行评估。使用DOT和MRI评估17例女性病人的18个乳腺病变（10个侵袭性癌．2个纤维腺瘤和6个良性囊肿；直径13～55mm）。在最初36例入选病人中一部分因技术问题而未行该方法检查。兴趣区（region of interest.ROI）的选择是MRI上显示的病变位置以及对侧健康乳腺的镜像部位。由2位观察者分别独自阅片并从定量和定性2方面评估ROI。使用信度检验（kappastatistics,

关键词：光学断层成像吸收乳腺癌乳腺影像学