检索结果-南通市图书馆

Remarks on the recent progress of Materials Genome Initiative

在线全文

学校读者我要写书评

暂无评论

Science Bulletin 2015年第22期60卷 1966-1968页

作者： Xiao-gang lu School of Materials Science and Engineering Shanghai University Materials Genome Institute Shanghai University

The Materials Genome Initiative(MGI)has attracted great attention globally since June 2011,when the US President Obama announced Advanced Manufacturing Partnership(AMP),in which MGI is a key *** June 2014,the US National Science and Technology Council published‘‘Materials Genome Initiative Strategic Plan’’,describing in detail the strategy that guides and coordinates US Federal activities and provides a clear technical path

关键词：基因组计划材料科学技术委员会美国总统先进制造组成部分 AMP

B_(111),B_(112),_(B113),and B_(114):The most stable core-shell borospherenes with an icosahedral B_(12) core at the center exhibiting superatomic behaviors

在线全文

学校读者我要写书评

暂无评论

Nano Research 2021年第12期14卷 4719-4724页

作者： Min Zhang Hai-gang lu Si-Dian Li Institute of Molecular Science Shanxi UniversityTaiyuan030006China

Boron allotropes are known to be predominately constructed by icosahedral B_(12) cages,while icosahedral-B_(12) stuffing proves to effectively improve the stability of fullerene-like boron nanoclusters in the size range between B_(98)–B_(102).However,the thermodynamically most stable core-shell borospherenes with a B_(12) icosahedron at the center still remains *** on the structural motif of D5h C_(70) and extensive first-principles theory calculations,we predict herein the high-symmetry C5v B111+(3)which satisfies the Wade’s n+1 and n+2 skeletal electron counting rules exactly and the approximately electron sufficient Cs B_(111)(4),Cs B_(112)(5),Cs B_(113)(6),and Cs B_(114)(7)which are the most stable neutral core-shell borospherenes with a B_(12) icosahedron at the center reported to date in the size range between B_(68)–B_(130),with Cs B112(5)being the thermodynamically most favorite species in the *** orbital and bonding analyses indicate that these spherically aromatic species all contain a negatively charged icosahedral B_(122)−core at the center which exhibits typical superatomic behaviors in the electronic configuration of 1S21P61D101F8,with its dangling valences saturated by twelve radial B-B 2c-2eσbonds between the B_(12) inner core and the B_(70) outer *** infrared(IR)and Raman spectra of the concerned species are computationally simulated to facilitate their future characterizations.

关键词： first-principles theory borospherenes structures bonding superatomic behaviors spherical aromaticity

Research and development on hypervelocity impact protection using Whipple shield:An overview

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2021年第6期17卷 1864-1886页

作者： Ken Wen Xiao-wei Chen Yong-gang lu State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing100081China Institute of Systems Engineering China Academy of Engineering PhysicsMianyangSichuan621999China

Whipple shield,a dual-wall system,as well as its improved structures,is widely applied to defend the hypervelocity impact of space debris(projectile).This paper reviews the studies about the mechanism and process of protection against hypervelocity impacts using Whipple ***-based experiment and numerical simulation for hypervelocity impact and protection are introduced *** steps of the Whipple shield protection are discussed in order,including the interaction between the projectile and bumper,the movement and diffusion of the debris cloud,and the interaction between the debris cloud and rear *** improvements of the protection performance focusing on these three steps are *** works in the last decade are mentioned *** prospects and suggestions for future studies are put forward.

关键词： Space debris Hypervelocity impact Debris cloud Whipple shield Ballistic limit

Kernel Estimation of Truncated Volterra Filter Model Based on DFP Technique and Its Application to Chaotic Time Series Prediction

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Electronics 2019年第1期28卷 127-135页

作者： ZHANG Yumei BAI Shulin lu gang WU Xiaojun Key Laboratory of Modern Teaching Technology Ministry of EducationShaanxi Normal University School of Computer Science Shaanxi Normal University School of Electronics and Information Northwestern Polytechnical University

In order to overcome some problems caused by improper parameters selection when applying Least mean square(LMS), Normalized LMS(NLMS) or Recursive least square(RLS) algorithms to estimate coefficients of second-order Volterra filter, a novel DavidonFletcher-Powell-based Second-order Volterra filter(DFPSOVF) is proposed. Analysis of computational complexity and stability are presented. Simulation results of system parameter identification show that the DFP algorithm has fast convergence and excellent robustness than LMS and RLS algorithm. Prediction results of applying DFPSOVF model to single step predictions for Lorenz chaotic time series illustrate stability and convergence and there have not divergence problems. For the measured multiframe speech signals, prediction accuracy using DFPSOVF model is better than that of Linear prediction(LP).The DFP-SOVF model can better predict chaotic time series and the real measured speech signal series.

关键词： Chaos Davidon-Fletcher-Powell algorithm Prediction model Second-order Volterra filter Speech signal

Upper mantle seismic anisotropy beneath a convergent boundary:SKS waveform modeling in central Tibet

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science China Earth Sciences 2014年第4期57卷 759-776页

作者： ZHAO Liang ZHAO Ming lu gang State Key Laboratory of Lithospheric Evolution Institute of Geology and GeophysicsChinese Academy of Sciences

This study used SKS waveforms from the International Deep Profiling of Tibet and the Himalayas(INDEPTH) III dataset and a new 2D method for modeling seismic waves in anisotropic media to construct an image of anisotropic structures beneath central Tibet.A preferred model revealed three-segment anisotropic structures in the upper mantle beneath the study *** modeling demonstrated that the anisotropy was mainly generated by the lithosphere but not the asthenosphere,and that an anisotropic model with a flatter axis of symmetry provides a more consistent interpretation of the observations than models having steeply dipping symmetry axes.A relatively low velocity zone may underlie or intermingle with the anisotropic structures in the northern portion of the *** tests also indicate that variations in the elastic constants and depth extent of the anisotropy assumed by the calculations do not affect the general conclusions,although trade-offs exist among certain model *** modeling results suggest that the complex seismic structures in central Tibet were associated with underthrusting of the Indian lithosphere beneath the Asian lithosphere;the inferred flat symmetry axis of the anisotropy was likely generated during this collision *** this were not the case,the inherited anisotropy would exhibit a steeply dipping axis of symmetry,parallel to the direction of underthrusting.

关键词： waveform modeling spectral element method upper mantle anisotropy central Tibet

Unraveling energy and charge transfer in type-II van der Waals heterostructures

在线全文

学校读者我要写书评

暂无评论

npj Computational Materials 2021年第1期7卷 1774-1782页

作者： Junyi Liu Zi Li Xu Zhang gang lu Department of Physics and Astronomy California State UniversityNorthridgeCA 91330-8268USA Institute of Applied Physics and Computational Mathematics P.O.Box 8009Beijing 100088China

Recent experiments observed significant energy transfer in type-II van der Waals(vdW)heterostructures,such as WS_(2)/MoSe_(2),which is surprising due to their staggered band alignment and weak spectral *** this work,we carry out first-principles calculations to shed light on energy and charge transfer in WS_(2)/MoSe_(2) *** excitonic effect in nonadiabatic electronic dynamics,our first-principles calculations uncover a two-step process in competing energy and charge transfer,unravel their relative efficiencies and explore the means to control their *** both Dexter and Förster mechanisms can be responsible for energy transfer,they are shown to operate at different *** excitonic effect is revealed to drive ultrafast energy and charge transfer in type-II WS_(2)/MoSe_(2) *** work provides a comprehensive picture of exciton dynamics in vdW heterostructures and paves the way for rational design of novel vdW heterostructures for optoelectronic and photovoltaic applications.

关键词： transfer energy charge

Role of silicon in steels on galvanized coatings

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2009年第2期22卷 138-145页

作者： Chunshan CHE Jintang lu gang KONG Qiaoyu XU College of Materials Science and Engineering South China University of Technology Guangzhou 510640 China

In this article, five kinds of silicon-containing steel sheets have been electrodeposited, and then immersed in a pure molten zinc bath at 450℃ for various periods of time. The results by scanning electron microscopy （SEM） show that the coating of the sample （0.09 wt pct Si） with iron-electrodeposited pretreatment eliminates the reactive zones which are found in the coating without iron-electrodeposited pretreatment. The galvanized sample （0.28 wt pct Si） with iron-electrodeposited pretreatment exhibits a compact and coherent coating. The coating of the sample （0.37 wt pct Si） with the iron-electrodeposited pretreatment experiences a transition from a compact and coherent coating to a reactive one. The energy dispersive spectrum （EDS） results reveal that for the galvanized samples with iron-electrodeposited pretreatment, excessive silicon accumulates on the surface of the substrate due to the low solubility of silicon in the Г, after the iron layer is depleted by the increasing growth of the Fe-Zn intermetallics. With the movement of the substrate/Г interface toward the substrate, silicon-enriched α-Fe peels off from the substrate and breaks into the particles. The particles move toward the δ layer through the Г layer because silicon-enriched α-Fe cannot be absorbed in the F layer. When the particles reach the δ/Г interface, they are dissolved in the δ laver, making the F laver thin or even vanish.

关键词： Zn coating Intermetallics Steel Electrodeposition Iron

Reaction of titanium investment castings made by Zr(CH3COO)2-Y2O3 shell

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2017年第6期36卷 465-471页

作者： Xin Guo Ya-Meng Wei Zhi-gang lu Department of Mechanical Engineering Tsinghua UniversityBeijing 100084 China Academy of Opto-Electronics Chinese Academy of SciencesBeijing 100094 China State Key Laboratory of Tribology Tsinghua UniversityBeijing 100084 China

The forming process and mechanism of the reaction of Ti-6Al-4V investment casting made by Zr（CH3COO）2-Y2O3 shell in vacuum casting was *** was manipulated to study the distributions and types of the reaction layers. The morphology and composition of the reaction layers were tested using field emission scanning electron microscopy（FESEM） combined with energy-dispersive spectroscopy（EDS）. Phase of the reaction layers was characterized by X-ray diffraction（XRD）.Composition of the shell reaction zone was measured by X-ray fluorescence（XRF） method. The results suggest the reaction contains oxidation and element evaporation, and the melt reacts little with the shell but mainly with the remnant gas. The reaction layers contain three types due to different forming stages： the titanium oxidation film, the concretion film and the shell reaction zone. The interfacial temperature and pressure affect the reaction mechanism and degree, leading to three types of concretion films that differ in thickness, content and color.

关键词： Titanium alloy Investment casting Reaction Oxidation Element evaporation

Thermodynamic modeling of Cr-Al-C and Ni-Al-C systems for low-density steels

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2020年第10期27卷 1190-1199页

作者： Wei-sen Zheng Yan-lin He Xiao-gang lu State Key Laboratory of Advanced Special Steel Shanghai UniversityShanghai 200444China School of Materials Science and Engineering Shanghai UniversityShanghai 200444China

The so-called low-density steels have generated a lot of interests with their high specific strength and ductility due to the addi-tion of the light element *** order to accelerate the low-density steel design,a thermodynamic database has been developedwithin the present author *** Al-containing systems,i.e.,Cr-Al-Cand Ni-Al-C,were modeled and optimirzed with CALPHAD approach based on the reliable binary *** Cr-Al-C,system,the Gibbs energy of Cr2AlC phasewas described by a temperature-dependent polynomial with the aid of the experimental data on the heat capacity,instead of estimating heat capacity from Ncumann-Kopp *** incongruent melting temperature of Cr2AlC is 1762 K with theinvariant reaction of liquid+Cr3C2+Al4C3→*** phase equilibria between Cr2AlC and binary phases were wellreproduced by using the present model *** Ni-Al-C system,the liquid,fec and bec phases have been optimizedto fit the carbon solubility in these three phases.A good agreement between the calculated and experimental data has beenobtained using the present description of Ni-Al-C *** reliable descriptions of the two ternary systems developedin the present work can be implemented into the thermodynamic database for low-density steels.

关键词： Cr-Al-C system Ni-Al-C system Thermodynamic model CALPHAD Low-density steel