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Synthesis, Crystal Structure and Spectrometry Study of Chiral N-Ethyl-N'-(2',3',4',6'-tetra-O-acetyl-β-D-glycosyl)-thiocarbamide

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Chinese Journal of Structural Chemistry 2003年第5期22卷 563-567页

作者： JIANfang-fang XIAOHai-Lian SUNPing-Ping z.AOPu-Su NewMaterials&FunctionCoordinationChemistryLaboratory QingdaoUniversityofScienceandTechnologyQingdao266042China MaterialsChemistryLaboratory NanjingUniversityofScienceandTechnologyNanjing210094China

The structure of chiral N-ethyl-N-(2,3,4,6-tetra-O-acetyl-b-D-glycosyl)-thio- carbamide was determined by X-ray diffraction method. It crystalliz.s in the monoclinic system, space group P21 with a = 7.6560(15), b = 10.311(2), c =14.181(3) ? b =100.88(3), C17H26N2O9S, Mr = 434.46, V = 1099.3(4) ?, z.= 2, Dc = 1.312 g/cm3, F(000) = 460, m = 0.196 mm-1, R = 0.0704 and wR = 0.1655. The total independent reflections were 5098, of which 1875 were observed with I ≥2s(I). The hexopyranosyl ring adopts a chair conformation. All the ring substituents are in the equatorial positions. The acetoxylmethyl group is in the gauche-gauche conformation. The S atom is in synperiplanar conformation, while the NCNC linkage is antiperiplanar. X-ray analysis shows that the absolute configuration of the chiral carbon atom at C(1) was proved to be b-form. The 1H NMR spectra and IR are in good agreement with the result of crystallography analysis. The NH…O intermolecular hydrogen bonds link the molecules into infinite chains connected by CH…O interactions.

关键词： crystal structure thiocarbamide b-D-glycopranosyl derivation hydrogen bonds chair conformation

Indirect Measurement of Material Thermal and Mechanical Properties during Welding

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Journal of Materials Science & Technology 2003年第Z1期19卷 173-175页

作者： Dongqing LI Jun TAO Qingguo Meng Hongyuan fang State Key Laboratory of Welding Harbin Institute of Technology 150001 Chins State Key Laboratory of Welding Harbin Institute of Technology 150001 Chins State Key Laboratory of Welding Harbin Institute of Technology 150001 Chins State Key Laboratory of Welding Harbin Institute of Technology 150001 Chins

By means of a newly developed non-contact detecting method, electronic speckle pattern interferometry (ESPI), a method of determining material property data during welding is studied. A TIG fixed-point welding process is modeled in which some achievements of simulation, such as the effect of welding pool on temperature field and nonlinear relation between convection coefficient and temperature, are all considered. In addition, by taking into account effect of heating rate, the workpiece is divided into near-weld z.ne and far-weld z.ne, which will be treated with different property values. When the displacement field computed with original property data is compared and matched with the experimental displacement field, which is measured by ESPI, these original data are adjusted properly. A group of raw properties are obtained and are corrected by statistical regression before they enter the simulation process *** such a loop of "simulation-comparison-modification", a set of property data that best satisfy the real condition are achieved finally. In such a way, a new method for measuring material properties during welding is found.

关键词： Material properties, Welding displacement field, Numerical simulation, ESPI

Three-dimensional Numerical Study on Temperature Field of Laser Bending of Sheet Metal

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Journal of Materials Science & Technology 2003年第Z1期19卷 59-61页

作者： Shunhong LIU Xiong fang Pengteng WAN Jing YAN Department of Materials Engineering Huazhong University of Science and Technology Wuhan 430074 China Department of Materials Engineering Huazhong University of Science and Technology Wuhan 430074 China Department of Materials Engineering Huazhong University of Science and Technology Wuhan 430074 China Department of Materials Engineering Huazhong University of Science and Technology Wuhan 430074 China

Laser bending of sheet metal is a flexible forming technique by using laser scanning. Based of temperature gradsmechanism, the temperature field of sheet metal bending process by using single laser scanning is studied with theANSYS soft. A finite element model of temperature field is built. The dynamic variation process and distributionof temperature field of laser bending at given parameters are analyz.d. Furthermore, the influence parameter on thepeak temperature and temperature grads are also studied.

关键词： Laser bending, Temperature field, Numerical simulation

A molecular mechanics approach for analyz.ng tensile nonlinear deformation behavior of single-walled carbon nanotubes

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Acta Mechanica Sinica 2007年第6期23卷 663-671页

作者： Yu Wang Daining fang Ai Kah Soh Bin Liu Department of Engineering Mechanics Tsinghua University Beijing 100084 China Department of Mechanical Engineering University of Hong Kong Hong Kong China

In this paper, by capturing the atomic information and reflecting the behaviour governed by the nonlinear potential function, an analytical molecular mechanics approach is proposed. A constitutive relation for single-walled carbon nanotubes （SWCNT＇s） is established to describe the nonlinear stress-strain curve of SWCNT＇s and to predict both the elastic properties and breaking strain of SWCNT＇s during tensile deformation. An analysis based on the virtual internal bond （VIB） model proposed by P. z.ang et al. is also presented for comparison. The results indicate that the proposed molecular mechanics approach is indeed an acceptable analytical method for analyz.ng the mechanical behavior of SWCNT＇s.

关键词： Molecular mechanics approach Carbon nanotube Constitutive relation Young's modulus

Numerical Analysis of Energy Effect in Laser-TIG Hybrid Welding

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Journal of Materials Science & Technology 2003年第Z1期19卷 23-26页

作者： Yanbin CHEN Liqun LI Junfei fang Xiaosong FENG National Key Laboratory of Advanced Welding Production Technology Harbin Institute of Technology Harbin 150001 Chlna National Key Laboratory of Advanced Welding Production Technology Harbin Institute of Technology Harbin 150001 Chlna National Key Laboratory of Advanced Welding Production Technology Harbin Institute of Technology Harbin 150001 Chlna National Key Laboratory of Advanced Welding Production Technology Harbin Institute of Technology Harbin 150001 Chlna

The hybrid source that combined CO2 laser with TIG arc to proceed welding was analyz.d. Based on an energymodel, the temperature field and weld shape were calculated numerically. The heat transfer characteristic of thehybrid heat source to workpiece and its effect to weld shape were also analyz.d. Through analyz.ng the enhancementeffect of the hybrid heat source, the absorption effect and defocusing effect of the hybrid arc to laser were calculated,and the regularity of the energy density to the current was obtained subsequently. At last, the critical energy matchesto induce the enhancement effect of CO2 laser-TIG arc hybrid welding were obtained.

关键词： Laser-TIG hybrid welding, Energy effect, Numerical simulation

Control of Titanium Alloy Thin Plate Welding Distortion by Trailing Peening

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Journal of Materials Science & Technology 2003年第Z1期19卷 184-186页

作者： Xuesong LIU Hongyuan fang Shude JI z.ibo DONG State Key Laboratory of Advanced Welding Production Technology Harbin Institute of TechnologyHarbin 150001 China State Key Laboratory of Advanced Welding Production Technology Harbin Institute of TechnologyHarbin 150001 China State Key Laboratory of Advanced Welding Production Technology Harbin Institute of TechnologyHarbin 150001 China State Key Laboratory of Advanced Welding Production Technology Harbin Institute of TechnologyHarbin 150001 China

The technology of trailing peening is a kind of promisingly bran-new technology which can be used to control weldingstress and distortion of Ti alloy thin plate. Control of TC4 Ti alloy thn plate welding stress and distortion underthe condition of conventional welding and trailing peening is performed, respectively. The results show that thetechnology of trailing peening effectively reduces deflection and transverse shrinkage of thin plate weldment. Themaximum deflection is decreased from 15 mm under the conditior of conventional welding to 5 mm, while the weldtransverse shrinkage is decreased from 0.5 mm to about 0.1 mm.

关键词： Control of residual stress and distortion, Trailing peening, TC4 Ti alloy

Growth and characteristics of InAsSb epilayers with a cutoff wavelength of 4.8 μm prepared by one-step liquid phase epitaxy

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Rare Metals 2009年第4期28卷 313-316页

作者： GAO Yuz.u GONG Xiuying fang Weiz.eng Akihiro Ishida College of Electronics and Information Engineering Tongji University Shanghai 201804 China Shanghai Institute of Technical Physics Chinese Academy of Sciences Shanghai 200083 China Shiz.oka University 3-5-1 Johoku Hamamatsu 432-8011 Japan

InAsSb epilayers with a cutoff wavelength of 4.8 μm have been successfully grown on InAs substrates by one-step liquid phase epitaxy （LPE） technology. The epilayers were characteriz.d by X-ray diffraction （XRD）, Fourier transform infrared （PTIR） transmittance measurements and scanning electron microscopy （SEM）. The influence of different growth conditions on the optical and structural properties of the materials was studied. The results revealed that the good crystalline quality, mirror smooth surface and flat interface of InAsSb epilayers were achieved. They benefited from optimiz.d growth conditions, i.e., sufficient homogeneity of the growth melt and a very slow cooling rate.

关键词： InAsSb liquid phase epitaxy crystalline quality cutoff wavelength scanning electron microscopy

Synthesis and Crystal Structure of O-Ethyl-N- (2,3,4-tri-O-acetyl-β-D-xylopyranosyl)-thiocarbamate

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Chemical Research in Chinese Universities 2005年第2期21卷 163-165页

作者： YANGBo z.ANGShu-sheng WANGYan-fang LIXue-mei JIAOKui CollegeofChemistryandChemicalEngineering OceanUniversityofChinaQingdao266003P.R.China CollegeofChemistryandMolecularEngineering QingdaoUniversityofScienceandTechnologyQingdao266042P.R.China

The crystal and molecular structures of O-ethyl-N-(2,3,4-tri-O-acetyl-β-D-xylopyranosyl)-thiocarbamate were determined by X-ray crystallography. It crystalliz.s in the orthorhombic system with space group P2(1)2(1)2(1), lattice parameters a=0.90636(18) nm, b=0.94716(19) nm, c=2.1855(4) nm, V=1.8762(7) nm 3, and z.4. All the substituents are in equatorial positions. There are four intramolecular interactions, each forming a five-membered ring. The molecules are linked by interactions to form three-dimensional framework. Atoms O6 and O8 show positional disorder.

关键词： O-Ethyl-N-(2,3,4-tri-O-acetyl-β-D-xylopyranosyl)-thiocarbamate Crystal structure Three-dimensional network

Constraints on Dark Energy from the CSST Galaxy Clusters

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Research in Astronomy and Astrophysics 2023年第4期23卷 110-120页

作者： Yufei z.ang Mingjing Chen z.onglue Wen Wenjuan fang CAS Key Laboratory for Research in Galaxies and Cosmology Department of AstronomyUniversity of Science and Technology of ChinaHefei 230026China School of Astronomy and Space Science University of Science and Technology of ChinaHefei 230026China National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China CAS Key Laboratory of FAST NAOCChinese Academy of SciencesBeijing 100101China

We study the potential of the galaxy cluster sample expected from the Chinese Space Station Telescope(CSST)survey to constrain dark energy *** modeling the distribution of observed cluster mass for a given true mass to be log-normal and adopting a selection threshold in the observed mass M_(200m)≥0.836×10^(14)h^(-1)M_(⊙),we find about 4.1×10^(5)clusters in the redshift range 0≤z.1.5 can be detected by the *** construct the Fisher matrix for the cluster number counts from CSST,and forecast constraints on dark energy parameters for models with constant(w_(0)CDM)and time dependent(w_(0)w_(a)CDM)equation of *** the self-calibration scheme,the dark energy equation of state parameter w_(0)of the w_(0)CDM model can be constrained toΔw_(0)=*** w_(a)is added as a free parameter,we obtainΔw_(0)=0.077 andΔw_(a)=0.39 for the w_(0)w_(a)CDM model,with a Figure of Merit for(w_(0),w_(a))of *** we have perfect knowledge of the observable-mass scaling relation("known SR"scheme),we would obtainΔw_(0)=0.012 for the w_(0)CDM model,andΔw_(0)=0.062 andΔw_(a)=0.24 for the w_(0)w_(a)CDM *** dark energy Figure of Merit of(w_(0),w_(a))increases to *** indicates again the importance of calibrating the observable-mass scaling relation for optically selected galaxy *** extending the_(max)imum redshift of the clusters from z.(max)~1.5 to z.(max)~2,the dark energy Figure of Merit for(w_(0),w_(a))increases to 89.72(self-calibration scheme)and 610.97("known SR"scheme),improved by a factor of~1.30 and~1.78,*** find that the impact of clusters’redshift uncertainty on the dark energy constraints is negligible as long as the redshift error of clusters is smaller than 0.01,achievable by *** also find that the bias in logarithm mass must be calibrated to be 0.30 or better to avoid significant dark energy parameter bias.

关键词： (cosmology:)dark energy-galaxies clusters general-(cosmology:)cosmological parameters