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A low-dimensional crystal growth model on an isotropic and quasi-free sustained substrate

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Chinese Physics B 2020年第3期29卷 420-426页

作者： Chenxi Lu Senjiang Yu Lingwei Li Bo Yang Xiangming Tao Gaoxiang Ye College of Materials and Environmental Engineering Hangzhou Dianzi UniversityHangzhou 310018China Department of Physics Zhejiang UniversityHangzhou 310027China

A new crystal growth theoretical model is established for the low-dimensional nanocrystals on an isotropic and quasifree sustained substrate. The driven mechanism of the model is based on the competitive growth among the preferential growth directions of the crystals possessing anisotropic crystal structures, such as the hexagonal close-packed and wurtzite structures. The calculation results are in good agreement with the experimental findings in the growth process of the lowdimensional Zn nanocrystals on silicone oil surfaces. Our model shows a growth mechanism of various low-dimensional crystals on/in the isotropic substrates.

关键词： crystal growth low-dimensional nanocrystals isotropic substrates preferential growth

On the material constants measurement method of a fluid-saturated transversely isotropic poroelastic medium

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Science China(Physics,Mechanics & Astronomy) 2019年第1期62卷 69-75页

作者： Yue Gao ZhanLi Liu Zhuo Zhuang Keh-Chih Hwang AML Department of Engineering Mechanics Tsinghua University Center for Mechanics and Materials Tsinghua University

The fluid-saturated transversely isotropic poroelastic medium could be widely found in nature, e.g., the sedimentary rocks underground. To determine the eight independent material constants for the transversely isotropic poroelastic medium, a series of tests are discussed. Two undrained tests and one drained test are suggested as a set of tests of the least amount. For the verification purpose, two additional drained tests are also introduced as an option. The atmospheric dried test is discussed as a replacement of the traditional infiltrated drained test to save the time waiting for an equilibrium state. Some microscopic material constants, i.e.,the unjacketed bulk coefficients, the porosity, and the compressibility of porous fluid, are measurable but unnecessary to determine the independent material constants of a poroelastic medium.

关键词： poroelastic constitutive model material constants measurement transversely isotropic medium

Stochastic modeling of subgrid-scale effects on particle motion in forced isotropic turbulence

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Chinese Journal of Chemical Engineering 2019年第12期27卷 2884-2891页

作者： Haoshu Shen YuxinWu Minmin Zhou Hai Zhang Guangxi Yue Key Laboratory for Thermal Science and Power Engineering of Ministry Education Department of Energy and Power EngineeringTsinghua UniversityBeijing 100084China Institute for Clean and Secure Energy Department of Chemical EngineeringUniversity of UtahSalt Lake City 84112United States

The subgrid-scale effects on particle motion were investigated in forced isotropic turbulence by DNS and priorLES *** the DNS field,the importance of Kolmogorov scaling to preferential accumulation was validated by comparing the radial distribution functions under various particle Stokes *** prior-LES fields were generated by filtering the DNS *** subgrid-scale Stokes number(StSGS)is a useful tool for determining the effects of subgrid-scale eddies on particle *** subgrid-scale eddies tend to accumulate particles with StSGSb 1 and disperse particles with 1 b StSGSb *** particles with StSGS?1,the effects of subgrid-scale eddies on particle motion can be *** order to restore the subgrid-scale effects,the Langevin-type stochastic model with optimized parameters was adopted in this *** model is effective for the particles with StSGS N 1 while has an adverse impact on the particles with StSGSb *** results show that the Langevin-type stochastic model tends to smooth the particle distribution in the isotropic turbulence.

关键词： Particle dispersion Subgrid-scale modeling Forced isotropic turbulence Stokes number

Plane Vibrations in a Transversely isotropic Infinite Hollow Cylinder Under Effect of the Rotation and Magnetic Field

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Computer Modeling in Engineering & Sciences 2017年第2期113卷 151-170页

作者： F.S.Bayones A.M.Abd-Alla Math.Dept. Faculty of ScienceTaif UniversitySaudi Arabia Mathematics Department Faculty of ScienceSohagEgypt

The aim of this paper is to study the effects of rotation and magnetic field on the plane vibrations in a transversely isotropic material of an infinite hollow *** natural frequency of the plane vibrations in the case of harmonic vibrations has been *** natural frequencies are calculated numerically and the effects of rotation and magnetic field are *** numerical results obtained have been illustrated graphically to understand the behavior of frequency equation with different values of frequencyωunder effects the rotation and magnetic *** was made with the results obtained in the presence and absence of the rotation and magnetic *** results indicate that the effect of rotation and magnetic field are very pronounced.

关键词： Plane transversely isotropic rotating magnetic field homogeneous transversely isotropic Natural frequencies

The 3-D non-axisymmetrical Lamb's problem in transversely isotropic saturated poroelastic media

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Science China(Technological Sciences) 2004年第5期47卷 526-549页

作者： HUANG Yi1 & WANG Xiaogang1,2 1. School of Civil Engineering, Xian University of Architecture & Technology, Xian 710055, China 2. Department of Civil Engineering, Qinghai University, Xining 810016, China Correspondence should be addressed to Huang Yi (email: huangyih@***) Received April 15, 2004 revised July 12, 2004 School of Civil Engineering Xi’an University of Architecture & Technology Xi’an China Department of Civil Engineering Qinghai University Xining China

Based on Biots theory on fluid-saturated porous media, the displacement functions are adopted to convert the 3-D Biots wave equations in the cylindrical coordinate for transversely isotropic saturated poroelastic media into two棗one 6-order and one 2-order棗uncoupling differential governing equations. Then, the differential equations are solved by the Fourier expanding and Hankel integral transform method. Integral solutions of soil skeleton displacements and pore pressure as well as the total stresses for poroelastic media are obtained. Furthermore, the systematic study on Lambs problems for the transversely isotropic saturated poroelastic media is performed. Integral solutions for surface radial, vertical and circumferential displacements are obtained in both cases of drained surface and undrained surface under the vertical and horizontal harmonic excitation force. In the end of this paper, the numerical examples are presented. The calculation results indicate that the difference between the model of isotropic saturated poroelastic media and that of transversely isotropic saturated poroelastic media is obvious.

关键词： transversely isotropic saturated poroelastic media, Biot's wave equations, Lamb's problems.

Three-dimensional,isotropic imaging of mouse brain using multi-view deconvolution light sheet microscopy

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Journal of Innovative Optical Health Sciences 2017年第5期10卷 94-100页

作者： Sa Liu Jun Nie Yusha Li Tingting Yu Dan Zhu Peng Fei School of Optical and Electronic Information Huazhong University of Science and Technology Wuhan 430074 P.R.China Britton Chance Center for Biomedical Photonics Wuhan National Laboratory for Optoelectronics Huazhong University of Science and Technology Wuhan 430074 P.R.China

We present a threedimensional(3D)isotropic imaging of mouse brain using light-sheet fuo-rescent microscopy(LSFM)in conjumction with a multi-view imaging *** common single view LSFM is used for mouse brain imaging,the brain tissue is 3D imaged under eight views in our study,by a home-built selective plane ilumination microscopy(SPIM).An output image containing complete structural infornation as well as significantly improved res olution(~4 times)are then computed based on these eight views of data,using a bead-guided multi-view registration and *** superior imaging quality,the astrocyte and pyrarmidal neurons together with their subcellular nerve fbers can be clearly visualized and *** further incuding other computational methods,this study can be potentially scaled up to map the conectome of whole mouse brain with a simple *** microscope.

关键词： Light sheet fuorescent microscopy multi-view dconvolution mouse brain imaging isotropic

Direct numerical simulation of compressible isotropic turbulence

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Science China Mathematics 2002年第11期45卷 1452-1460页

作者：李新亮傅德薰马延文 LNM Institute of Mechanics Chinese Academy of Sciences Beijing China LHD Institute of Mechanics Chinese Academy of Sciences Beijing China

Direct numerical simulation (DNS) of decaying compressible isotropic turbulence at tur-bulence Mach numbers of Mt = 0.2-0.7 and Taylor Reynolds numbers of 72 and 153 is per-formed by using the 7th order upwind-biased difference and 8th order center difference *** show that proper upwind-biased difference schemes can release the limit of 'start-up'problem to Mach *** effects on the statistics of turbulent flow as well as the mechanics of shockletsin compressible turbulence are also studied, and the conclusion is drawn that high Mach numberleads to more dissipation. Scaling laws in compressible turbulence are also analyzed. Evidence isobtained that scaling laws and extended self similarity (ESS) hold in the compressible turbulentflow in spite of the presence of shocklets, and compressibility has little effect on scaling exponents.

关键词： direct numerical simulation, isotropic turbulence, compressibility effect, scaling law.

Hypersurfaces with isotropic Para-Blaschke Tensor

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Acta Mathematica Sinica,English Series 2014年第7期30卷 1195-1209页

作者： Jian Bo FANG Kun ZHANG Department of Mathematics and Statistics Chuxiong Normal University

Let Mn be an n-dimensional submanifold without umbilical points in the （n ＋ 1）-dimen- sional unit sphere Sn＋l. Four basic invariants of Mn under the Moebius transformation group of Sn＋1 are a 1-form Ф called moebius form, a symmetric （0, 2） tensor A called Blaschke tensor, a symmetric （0, 2） tensor B called Moebius second fundamental form and a positive definite （0, 2） tensor g called Moebius metric. A symmetric （0,2） tensor D = A ＋ μB called para-Blaschke tensor, where μ is constant, is also an Moebius invariant. We call the para-Blaschke tensor is isotropic if there exists a function ,λ such that D = λg. One of the basic questions in Moebius geometry is to classify the hypersurfaces with isotropic para-Blaschke tensor. When λ is not constant, all hypersurfaces with isotropic para-Blaschke tensor are explicitly expressed in this paper.

关键词： Moebius geometry para-Blaschke tensor isotropic

Fabrication of metal suspending nanostructures by nanoimprint lithography(NIL) and isotropic reactive ion etching(RIE)

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Science China(Technological Sciences) 2009年第5期52卷 1181-1186页

作者： XIE GuoYong ZHANG Jin ZHANG YongYi ZHANG YingYing ZHU Tao LIU ZhongFan Center for Nanoscale Science and Technology(CNST) College of Chemistry and Molecular EngineeringPeking UniversityBeijing 100871China Nanotechnology Industrialization Base of China Tianjin 300457China

We report herein a rational approach for fabricating metal suspending nanostructures by nanoimprint lithography(NIL) and isotropic reactive ion etching(RIE).The approach comprises three principal steps:(1) mold fabrication,(2) structure replication by NIL,and(3) suspending nanostructures creation by isotropic *** this approach,suspending nanostructures with Au,Au/Ti or Ti/Au bilayers,and Au/Ti/Au sandwiched structures are *** Au nanostructures,straight suspending nanostructures can be obtained when the thickness of Au film is up to 50 nm for nano-bridge and 90 nm for nano-finger *** the thickness of Au is below 50 nm for nano-bridge and 90 nm for nano-finger,the Au suspending nanostructures bend upward as a result of the mismatch of thermal expansion between the thin Au films and Si *** leads to residual stresses in the thin Au *** Au/Ti or Ti/Au bilayers nanostructures,the cantilevers bend toward Au film,since Au has a larger thermal expansion coefficient than that of *** in the case of sandwich structures,straight suspending nanostructures are obtained,this may be due to the balance of residual stress between the thin films.

关键词： suspending nanostructure fabrication nanoimprint lithography(NIL) isotropic reactive ion etching(RIE)