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Acta mechanica Sinica 2009年第2期25卷 149-160页

作者： m.Saka T.Hasegawa Department of Nanomechanics Tohoku University

Temperature is one of the physical quantifies through which quantitative evaluation of the safety and reliability of industrial products can be achieved, and this has been used widely in practice. Under any environmental condifion, regardless of the size of the object to be inspected, accurate and reliable measurement of temperature is of great practical importance. This review article presents a simple and direct method of temperature measurement, that can be applied to the local areas with difficulty in measuring the temperature by using normal thermometers. In the present article, two different application examples are demonstrated. One addresses the study of the electromigration of solders which are used as bonding metals in electronic devices （micro-structures）. The application of the method to the shaft of a motor used in heavy industrial fields is explained as the second.

关键词： Temperature measurement Chemicalreagents melting point Temperature distribution

Wave Energy Estimation by Using A Statistical Analysis and Wave Buoy Data near the Southern Caspian Sea

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China Ocean Engineering 2015年第2期29卷 275-286页

作者： A.R.Zamani m.A.Badri Research Institute for Subsea Science and Technology Isfahan University of Technology

Statistical analysis was done on simultaneous wave and wind using data recorded by discus-shape wave buoy. The area is located in the southern Caspian Sea near the Anzali Port. Recorded wave data were obtained through directional spectrum wave analysis. Recorded wind direction and wind speed were obtained through the related time series as well. For 12-month measurements（may 25 2007-2008）, statistical calculations were done to specify the value of nonlinear auto-correlation of wave and wind using the probability distribution function of wave characteristics and statistical analysis in various time periods. The paper also presents and analyzes the amount of wave energy for the area mentioned on the basis of available database. Analyses showed a suitable comparison between the amounts of wave energy in different seasons. As a result, the best period for the largest amount of wave energy was known. Results showed that in the research period, the mean wave and wind auto correlation were about three hours. Among the probability distribution functions, i.e Weibull, Normal, Lognormal and Rayleigh, ＂Weibull＂ had the best consistency with experimental distribution function shown in different diagrams for each season. Results also showed that the mean wave energy in the research period was about 49.88 k W/m and the maximum density of wave energy was found in February and march, 2010.

关键词： probability distribution function nonlinear auto-correlation wave energy statistical analysis Anzali Port

Synthesis and Crystal Structure of a New Potassium Yttrium Diphosphate Dihydrate KYP_2O_7·2H_2O

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Chinese Journal of Structural Chemistry 2008年第10期27卷 1199-1204页

作者： Férid m Horchani-Naifer K Unité de Recherches de matériaux de Terres Rares Centre National de Recherches en Sciences des MatériauxB.P.95 Hammam-Lif 2050Tunisie

The dihydrated potassium yttrium diphosphate, KYP2O7·2H2O, has been synthesized for the first time. Single-crystal XRD study has allowed the determination of its structure and correct formula. It crystallizes in the monoclinic system, space group P21/c, with the cell parameters a = 7.7069（3）, b = 10.5801（4）, c = 10.0204（5）A,β = 93.24（3）A, V= 815.76（6）A^3, Z= 4, mr = 337.98, F（000） = 656, Dc = 2.752 g/cm^3 and/t = 8.073 mm^-1. The single-crystal structure was solved from 1856 unique reflections with the final R = 0.0365 and wR = 0.0772, refined with 119 parameters. The atomic arrangement of KYP2O7·2H2O is built by the P2O7 groups, the YO7 and the KO10 polyhedrons which are connected by corner and edge-sharing to form a three-dimensional framework. Water molecules are directly bonded to the Y and K atoms, and they are located in channels running along the a direction.

关键词： crystal structure yttrium diphosphate infrared spectrum TgA-DTA analysis

modeling of shear induced coarsening effects in semi-solid alloys

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Transactions of Nonferrous metals Society of China 2010年第9期20卷 1696-1701页

作者： m.mODIgEL L A.POLA AVT Chair of Mechanical Process EngineeringRWTH Aachen University Dipartimento di Ingegneria meccanica e Industriale Uni.degli Studi di Brescia

In long-term rheological shear experiments with semi-solid alloys, coarsening of the particles will falsify the interpretation of the experimental *** coarsening is intensified by the shear induced convection and the mean size of the particles is changed significantly during the experiments.A simple model has been set up which takes the influence of the convection into *** resulting growth law has been simplified for diffusion and convection dominated *** growth law was verified with shear experiments in a Searl-rheometer with A356 and tin-lead *** experiments demonstrated that under convection the growth follows a linear time law and that the rate constant depends on the root of the shear *** correction of experimental results to gain the true viscosity function is demonstrated for a shear jump experiment with A356.

关键词： microstructure coarsening Ostwald ripening flow function viscosity rheology semi-solid alloys

Observations on carbon and nitrogen content of suspended matter in a headwater stream in Hong Kong

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Journal of Environmental Sciences 2004年第4期16卷 533-538页

作者： m.R.Peart gUANDong-sheng Departmentofgeography UniversityofHongKongHongKong DepartmentofEnvironmentalScience SunYatsen（Zhongshan）University

The total carbon(C) and total nitrogen(N) content of suspended matter in a small undisturbed headwater drainage basin in the New Territories of Hong Kong has been monitored. mean C and N contents were 12.85% and 0.99% respectively for 132 samples. Samples collected under stableflow conditions had mean C and N contents of 12.81% and 1.06% respectively. Stormflow samples had mean C and N values of 12.86% and 0.97% respectively, which were very similar to the levels observed under stableflow conditions. The mean C∶N ratios of 12.47 and 13.39 for stableflow and stormflow also reveal little difference according to hydrologic conditions. When all the data is considered little difference is observed in C and N according to the season. However, in winter there is a significant difference in C and N content between stable and stormflow samples. When C and N are plotted against water level the scattergraphs suggested that as stage increases the percentage of C and N in the suspended matter declines. Scattergraphs of C and N against suspended sediment concentration reveal a negative association. Comparison has been made between fresh leaf C, N and C/N ratio for trees and shrubs and the suspended matter. Fresh leaves do not appear to contribute significantly to suspended matter. The C/N ratio of suspended matter would also seem to exclude woody material and algae as sources of suspended matter.

关键词： carbon nitrogen suspended matter Hong Kong

A work-hardening and softening constitutive model for sand:modified plastic strain energy approach

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Acta mechanica Sinica 2005年第1期21卷 76-86页

作者： FanglePeng m.S.A.Siddiquee ShaomingLiao DepartmentofgeotechnicalEngineering TongiiUniversityShanghai200092China DepartmentofCivilEngineering TheUniversityofTokyoTokyo1138656Japan DepartmentofgeotechnicalEngineering TongiiUniversityShanghai200092China//DepartmentofCivilEngineeringTheUniversityofTokyoTokyo1138656Japan

The paper describes an energy-based constitutive model for sand, which is modified based on the modified plastic strain energy approach, represented by a unique relationship between the modified plastic strain energy and a stress parameter, independent of stress history. The modified plastic strain energy approach was developed based on results from a series of drained plastic strain compression tests along various stress paths on saturated dense Toyoura sand with accurate stress and strain measurements. The proposed model is coupled with an isotropically work-hardening and softening, non-associtated, elasto-plastic material description. The constitutive model concerns the inherent and stress system-induced cross-anisotropic elastic deformation properties of sand. It is capable of simulating the deformation characteristics of stress history and stress path, the effects of pressure level, anisotropic strength and void ratio, and the strain localization.

关键词： Sand Energy-based Hardening and softening Elasto-plastic model Stress-strain relation

Water entry of decelerating spheres simulations using improved ISPH method

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Journal of Hydrodynamics 2018年第6期30卷 1120-1133页

作者： Abdelraheem m.Aly mitsuteru Asai Department of mathematics Faculty of Science King Khalid University Department of mathematics Faculty of Science South Valley University Department of Civil Engineering Kyushu University

In this paper, we simulated the vertical impact of spheres on a water surface using three-dimensional incompressible smoothed particle hydrodynamics(3-D ISPH) method. The sphere motion is taken to be a rigid body motion and it is modeled by ISPH method. The governing equations are discretized and solved numerically using ISPH method. A stabilized incompressible SPH method by relaxing the density invariance condition is adopted. Here, we computed the motions of a rigid body by direct integration of the fluid pressure at the position of each particle on the body surface. The equations of translational and rotational motion were integrated in time domain to update the position of the rigid body at each time step. In this study, we improved the boundary treatment between fluid and fixed solid boundary by using virtual marker technique. In addition, an improved algorithm based on the virtual marker technique for the boundary particles is proposed to treat the moving boundary of the rigid body motion. The force exerted on the moving rigid boundary particles by the surrounding particles, is calculated by the SPH approximation at the virtual marker points. The applicability and efficiency of the current ISPH method are tested by comparison with reference experimental results.

关键词： Incompressible smoothed particle hydrodynamics(ISPH) free surface flow sphere rigid body water entry

mechanical characterization of the role of defects in sintered FeCrAIY foams

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Acta mechanica Sinica 2007年第4期23卷 383-398页

作者： m.Kepets A.P.Dowling Engineering Department Cambridge UniversityCambridge CB2 1PZUK

Open celled metal foams fabricated through metal sintering are a new class of material that offers novel mechanical and acoustic properties. Previously, polymer foams have been widely used as a means of absorbing acoustic energy. However, the structural applications of these foams are limited. The metal sintering approach offers a costeffective means for the mass-production of open-cell foams from a range of materials, including high-temperature steel alloys. In this first part of two-paper series, the mechanical properties of open-celled steel alloy （FeCrA1Y） foams were characterized under uniaxial compression and shear loading. Compared to predictions from established models, a significant knockdown in material properties was observed. This knockdown was attributed to the presence of defects throu- ghout the microstructure that result from the unique fabrication process. Further in situ tests were carried out in a SEm （scanning electronic microscope） in order to investigate the effects of defects on the properties of the foams. Typically, the onset of plastic yielding was observed to occur at defect locations within the microstructure. At lower relative densities, ligament bending dominates, with the deformation initializing at defects. At higher relative densities, an additional deformation mechanism associated with membrane elements was observed. In the follow-up of this paper, a finite element model will be constructed to quantify the effects of defects on the mechanical performance of the opencell foam.

关键词： metal foam Defect mechanical characterization SEm

Spin and pseudospin symmetric Dirac particles in the field of Tietz-Hua potential including Coulomb tensor interaction

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Chinese Physics B 2013年第9期22卷 233-244页

作者： Sameer m. Ikhdair majid Hamzavi Department of Physics Faculty of ScienceAn-Najah National UniversityNew CampusJunaidNablusWest BankPalestine Department of Electrical and Electronic Engineering Near East University Department of Science and Engineering Abhar BranchIslamic Azad University

Approximate analytical solutions of the Dirac equation for Tietz-Hua （TH） potential including Coulomb-like tensor （CLT） potential with arbitrary spin-orbit quantum number K are obtained within the Pekeris approximation scheme to deal with the spin-orbit coupling terms K（K± 1）r^-2. Under the exact spin and pseudospin symmetric limitation, bound state energy eigenvalues and associated unnormalized two-component wave functions of the Dirac particle in the field of both attractive and repulsive TH potential with tensor potential are found using the parametric Nikiforov-Uvarov （NU） method. The cases of the morse oscillator with tensor potential, the generalized morse oscillator with tensor potential, and the non-relativistic limits have been investigated.

关键词： Dirac equation Tietz-Hua (TH) potential Coulomb-like tensor (CLT) potential generalizedmorse potential

Small scale effects on buckling and postbuckling behaviors of axially loaded Fgm nanoshells based on nonlocal strain gradient elasticity theory

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Applied mathematics and mechanics(English Edition) 2018年第4期39卷 561-580页

作者： S.SAHmANI A.m.FATTAHI Department of mechanical Engineering Bandar Anzali Branch Islamic Azad University Department of mechanical Engineering Tabriz Branch Islamic Azad University

By means of a comprehensive theory of elasticity, namely, a nonlocal strain gradient continuum theory, size-dependent nonlinear axial instability characteristics of cylindrical nanoshells made of functionally graded material(Fgm) are examined. To take small scale effects into consideration in a more accurate way, a nonlocal stress field parameter and an internal length scale parameter are incorporated simultaneously into an exponential shear deformation shell theory. The variation of material properties associated with Fgm nanoshells is supposed along the shell thickness, and it is modeled based on the mori-Tanaka homogenization scheme. With a boundary layer theory of shell buckling and a perturbation-based solving process, the nonlocal strain gradient load-deflection and load-shortening stability paths are derived explicitly. It is observed that the strain gradient size effect causes to the increases of both the critical axial buckling load and the width of snap-through phenomenon related to the postbuckling regime, while the nonlocal size dependency leads to the decreases of them. moreover, the influence of the nonlocal type of small scale effect on the axial instability characteristics of Fgm nanoshells is more than that of the strain gradient one.

关键词： nanomechanics functionally graded material(Fgm) nonlocal strain gradient theory nonlinear instability perturbation technique