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Investigation of the mean free path of projectile fragments produced in ^16O-Em collision at 60 A GeV

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Chinese Physics B 2004年第7期13卷 1000-1004页

作者：张东海巩进生 InstituteofModernPhysicsandPhysicsDepartment ShanxiTeachers'UniversityLinfen041004China

Results are presented for an investigation of the mean free path of projectile fragments with charge 3 ≤ Z ≤ 8,produced by 60 A GeV 16O in nuclear emulsion. No dependence of mean free path on the distance from the p... 详细信息

关键词： relativistic heavy-ion collision projectile fragments mean free path

A mean free path approach to the micro/nanochannel gas flows

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Advances in Aerodynamics 2020年第1期2卷 221-235页

作者： Jianfei Xie Department of Mechanical Engineering University of DerbyDerby DE223AWUnited Kingdom

We investigate the gas flows near to solid surfaces in terms of the local spatial variation in the molecular mean free path(MFP).Molecular dynamics(MD)is the appropriate scientific tool for obtaining molecularly-accurate dynamic information in micro and nano-scale gas flows,and has been used to evaluate the molecular mean free path of *** the calibration procedure,the viscosity of a gas in the homogeneous case can be recovered in our MD simulations and reach good agreement with the theoretical prediction and data from *** surface-bounded gas flows,if the collisions between gas molecules and walls are counted,a spatially-varying mean free path is presented,and for the first time we have observed that the distribution of the free paths deviates from the exponential one and spikes appear in their distributions at larger Kn,*** the transition flow *** on elementary kinetic theory,the effective viscosity of the gas derived from the mean free path has been incorporated into the framework of the continuum-fluid dynamics equations,and micro-Couette flows are performed to demonstrate this potential application.

关键词： Rarefied gas mean free path Effective viscosity Molecular dynamics 1 Introduction

Immunity of electronic and transport properties of phosphorene nanoribbons to edge defects

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Nano Research 2016年第6期9卷 1723-1734页

作者： Mirko Poljak Tomislav Suligoj Micro and Nano Electronics Laboratory Faculty of Electrical Engineering and Computing University of Zagreb Unska 3 HR-10000Zagreb Croatia

We present an extensive study of the electronic properties and carrier transport in phosphorene nanoribbons （PNRs） with edge defects by using rigorous atomistic quantum transport simulations. This study reports on the size- and defect-dependent scaling laws governing the transport gap, and the mean free path and carrier mobility in the PNRs of interest for future nanoelectronics applications. Our results indicate that PNRs with armchair edges （aPNRs） are more immune to defects than zig-zag PNRs （zPNRs）, while both PNR types exhibit superior immunity to defects relative to graphene nanoribbons （GNRs）. An investigation of the mean free path demonstrated that even in the case of a low defect density the transport in PNRs is diffusive, and the carrier mobility remains a meaningful transport parameter even in ultra-small PNRs. We found that the electron-hole mobility asymmetry （present in large-area phosphorene） is retained only in zPNRs for W 〉 4 nrn, while in other cases the asymmetry is smoothed out by edge defect scattering. Furthermore, we showed that aPNRs outperform both zPNRs and GNRs in terms of carrier mobility, and that PNRs generally offer a superior mobility-bandgap trade-off, relative to GNRs and monolayer MoS2. This work identifies PNRs as a promising material for the extremely scaled transistor channels in future posbsilicon electronic technology, and presents a persuasive argument for experimental work on nanostructured phosphorene.

关键词： phosphorene nanoribbons atomistic quantumtransport simulation edge defects transport gap mean free path electron and hole mobility

Thermal Transport Mechanism of Amorphous HfO_(2):A Molecular Dynamics Based Study

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Journal of Thermal Science 2022年第4期31卷 1052-1060页

作者： ZHANG Honggang WEI Han BAO Hua University of Michigan-Shanghai Jiao Tong University Joint Institute Shanghai Jiao Tong UniversityShanghai 200240China

Amorphous hafnium dioxide(a-HfO_(2))has attracted increasing interest in the application of semiconductor devices due to its high dielectric ***,the thermal transport properties of a-HfO_(2) are not well understood,which hinders its potential application in *** this work,we systematically investigate the thermal transport property of a-HfO_(2) using the molecular dynamics *** non-equilibrium molecular dynamics simulations reveal that the thermal conductivity of a-HfO;is length-dependent below 100 *** decomposed heat current further proves that the thermal transport of propagons and diffusons is sensitive to the system *** thermal conductivity is found to increase with temperature using Green-Kubo mode *** also quantify the contribution of each carrier to the thermal conductivity at different *** find that propagons are more important than diffusons in thermal transport at low temperatures(<100 K).In comparison,diffusons dominate heat transport at high *** have negligible contribution to the total thermal conductivity.

关键词： amorphous HfO2 molecular dynamics thermal conductivity mean free path size effect temperature effect

Microstructure and mechanical properties of WC-Co-based cemented carbide with bimodal WC grain size distribution

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稀有金属:英文版 2023年第8期42卷 2809-2815页

作者： Rui-Jun Cao Chen-Guang Lin Xing-Cheng Xie Zhong-Kun Lin Powder Metallurgy and Special Materials Department General Research Institute for Nonferrous MetalsBeijing 100088China

In order to improve the wear resistance of coarse-grained WC-Co cemented carbides,the fine WC powder were used to reinforce the metallic *** WC-Co-based cemented carbides having bimodal WC grain size distributions were synthesized by liquid phase *** comparison,the cemented carbides having unimodal WC grain size distributions were *** microstructure,hardness,fracture toughness and wear resistance of these cemented carbides were *** results show that adding fine WC powder is an effective method to improve the wear resistance of coarsegrained WC-Co cemented *** WC size,mean free path and fracture toughness decrease with the addition of fine WC powder,while the hardness exhibits an opposite *** impact-wear coefficient of bimodal distribution cemented carbides is noticeably lower than that of the unimodal one with the same hardness,which means that the cemented carbides with bimodal grain structure have better combination of hardness and impact-abrasive wear *** impact-abrasive wear mechanism of the bimodal cemented carbides is that the fine WC grains prevent abrasive wear and the coarse WC grains prevent impact wear.

关键词： WC-Co cemented carbide Impact wearing Bimodal distribution Hardness mean free path

Improvement of interfacial electron scattering by introduced NiFe nanoparticles

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Rare Metals 2012年第2期31卷 117-120页

作者： Huangfu, Jiashun Liu, Yang Feng, Chun Yu, Guanghua Li, Baohe Department of Materials Physics and Chemistry University of Science and Technology Beijing Beijing 100083 China School of Science Beijing Technology and Business University Beijing 100048 China

Ta/MgO/NiFe/MgO/Ta ultrathin films with and without intercalation of NiFe nanoparticles in MgO layers were prepared by magnetron sputtering, followed by a vacuum annealing process. The measured and calculated results show that the former has higher specular electron scattering (SES) parameter at MgO/NiFe interfaces, lower resistivity, and higher magnetoresistance (MR). The improved transport properties (TPs) are mainly attributed to the suppressed diffuse electron scattering by means of the introduction of NiFe nanoparticles.

关键词： specular electron scattering mean free path MgO NiFe nanoparticle

The　physical　implication　of　coda　amplitude　ratio　and　its　possible　application

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Acta Seismologica Sinica(English Edition) 1998年第4期11卷 441-448页

作者： Zhang, Tian-Zhong Ma, Yun-Sheng Huang, Rong-Liang Institute of Geophysics China Seismological Bureau Beijing China

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ＴｈｅｐｈｙｓｉｃａｌｉｍｐｌｉｃａｔｉｏｎｏｆｃｏｄａａｍｐｌｉｔｕｄｅｒａｔｉｏａｎｄｉｔｓｐｏｓｓｉｂｌｅａｐｐｌｉｃａｔｉｏｎＴＩＡＮ－ＺＨＯＮＧＺＨＡＮＧ（张天中）ＹＵＮ－ＳＨＥＮＧＭＡ（马支生）ＲＯＮＧ－ＬＩＡＮＧＨＵＡＮＧ（黄蓉良）Ｉｎ...

关键词： coda amplitude ratio energy ratio coda Q mean free path seismic precursors

Monte Carlo Simulations of Elastic Scattering with Applications to DC and High Power Pulsed Magnetron Sputtering for Ti3_(S)iC_(2)

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Communications in Computational Physics 2012年第5期11卷 1618-1642页

作者： Jurgen Geiser Sven Blankenburg Department of Mathematics Humboldt-Universitat zu BerlinD-10099 BerlinGermany Department of Physics Humboldt-Universitat zu BerlinD-10099 BerlinGermany.

We simulate the particle transport in a thin film deposition process made by PVD(physical vapor deposition)and present several models for projectile and target collisions in order to compute the mean free path and the differential cross section(angular distribution of scattered projectiles)of the scattering process.A detailed description of collision models is of the highest importance in Monte Carlo simulations of high power impulse magnetron sputtering and DC *** derive an equation for the mean free path for arbitrary interactions(cross sections)that includes the relative velocity between the *** apply our results to two major interaction models:hard sphere interaction&screened Coulomb *** types of interaction separate DC sputtering from HIPIMS.

关键词： DC sputtering MAX-phases mean free path particle in cell Monte Carlo collisions Monte Carlo Markov chain

Synthesis and Spectroscopy of Silica Nanoparticles as Scatter Centers in Random Gain Porous Media

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光谱学与光谱分析 2015年第2期35卷 334-339页

作者： Firas J.Kadhim Baha T.Chiad Nathera A.Ali Jafer F.Odah Department of Physics College of ScienceUniversity of Baghdad Department of Physics College of ScienceUniversity of Al-Muthanna

This work was carried out to synthesis a silica matrix by sol-gel technique,which used as host to Kiton Red laser dye doped with silica nanoparticles,which also prepared by sol-gel technique,to obtain KRSiO2 nanoparticles confined in silica xerogel *** rods at different pH values were successfully *** different values of pH cause different size of obtained nanoparticles,these nanoparticles act as scatter centers in the *** spontaneous emission(ASE),threshold pumping energy(Eth),and mean free path(lt)for photons in the rods have been *** results show that the values of bandwidth at full width half-maximum(FWHM)and the threshold energy are about 8.7nm and 12 mJ respectively.

关键词： Spectroscopy Keton Red Sol-Gel technique mean free path