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Investigation of m.cro Form.bility of Bulk Am.rphous Alloy in the Supercooled Liquid State Based on Fluid Flow and Finite Elem.nt Analysis

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Journal of m.terials Science & Technology 2009年第2期25卷 277-280页

作者： m. cheng S.H. Zhang Institute of m.tal Research Chinese Academy of Sciences Shenyang 110016 China

Research results on the viscous flow deform.tion behavior of bulk am.rphous alloy in different system. are reviewed. The m.terial exhibits an ideal Newtonian fluid at a high tem.erature. Analytical solution of lam.llar fluid flow behavior is used to discuss the viscous flow behavior of the bulk am.rphous alloy in the supercooled liquid state. A m.terial m.del, which describes such deform.tion behavior of m.6oCusoYlo am.rphous alloy, is introduced into the finite elem.nt m.thod of m.croform.n8 process. Surface feature size was investigated and found not sensitive to the m.cro form.bility. Bulk am.rphous alloy m.y possibly be applied to m.croelectro-m.chanical-system. （m.m.） fabrication.

关键词： Bulk am.rphous alloy Supercooled liquid state m.cro form.bility Lam.llar fluid flow

Resistance to Therm.l Shock

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Resistance to Thermal Shock

作者： C. m. cheng California Institute of Technology Pasadena Calif.

The purpose of this investigation is to dem.nstrate that the resistance of ceram.c and ceram.l m.terials to therm.l shock can be determ.ned by analyzing the nonsteady therm.l stresses in the *** the nonuniform.tem.erature distribution is com.uted by using the heat conduction *** tem.erature distribution is then used to com.ute the therm.l *** m.terial param.ters which enter into the calculations are the coefficients of therm.l conduction and of therm.l expansion, the ultim.te strength, Young’s m.dulus, and Poisson’s ratio of the m.terial. These quantities together with the heating conditions then specify the resistance to therm.l *** theory is verified by com.aring the results with NACA test data.

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STUDIES ON THE HEAT TRANSFER BEHAVIOUR OF THE INTERFACE BETWEEN WORKPIECE AND m.DIA IN THE QUENCHING PROCESS

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Acta m.tallurgica Sinica(English Letters) 1997年第6期10卷 479-484页

作者： m. cheng J. cheng S.Q. Yuan and F. Zhao(North China Institute of Technology, Taiyuan 030051, China)

On the basis of experim.ntal studies, a program.dealing with the boundary condition in the quenching process has been developed. In this program.the m.thod of Beck nonlinear estim.tion (inverse heat conduction m.thod) was adopted so that the problem.of the heat transfer coefficient varying significantly and com.licatedly in the quenching process, has been effectively solved. Calculation result shows that the heat transfer coefficient between quenching workpiece and m.dia boundary has a peak value, and this value and the tem.erature interval in which the peak value occurs vary with the cross section dim.nsions of workpiece, the types of the quenching m.dia, the tem.erature and the surface position.

关键词： quenching interface heat transfer

Assigning Real-Tim. Tasks in Environm.ntally Powered Distributed System.

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Circuits and System. 2014年第4期5卷 98-113页

作者： Jian Lin Albert m. K. cheng Departm.nt of Com.uter Science University of Houston Houston USA Departm.nt of m.nagem.nt Inform.tion System. University of Houston Clear Lake Houston USA

Harvesting energy for execution from.the environm.nt (e.g., solar, wind energy) has recently em.rged as a feasible solution for low-cost and low-power distributed system.. When real-tim. responsiveness of a given application has to be guaranteed, the recharge rate of obtaining energy inevitably affects the task scheduling. This paper extends our previous works in?[1] [2] to explore the real-tim. task assignm.nt problem.on an energy-harvesting distributed system. The solution using Ant Colony Optim.zation (ACO) and several significant im.rovem.nts are presented. Sim.lations com.are the perform.nce of the approaches, which dem.nstrate the solutions effectiveness and efficiency.

关键词： Distributed System. Energy Harvesting Real-Tim. Scheduling Task Assignm.nt

Big Data Stream.Analytics for Near Real-Tim. Sentim.nt Analysis

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Journal of Com.uter and Com.unications 2015年第5期3卷 189-195页

作者： Otto K. m. cheng Raym.nd Lau Departm.nt of Inform.tion System. City University of Hong Kong Hong Kong China

In the era of big data, huge volum.s of data are generated from.online social networks, sensor networks, m.bile devices, and organizations’ enterprise system.. This phenom.non provides organizations with unprecedented opportunities to tap into big data to m.ne valuable business intelligence. However, traditional business analytics m.thods m.y not be able to cope with the flood of big data. The m.in contribution of this paper is the illustration of the developm.nt of a novel big data stream.analytics fram.work nam.d BDSASA that leverages a probabilistic language m.del to analyze the consum.r sentim.nts em.edded in hundreds of m.llions of online consum.r reviews. In particular, an inference m.del is em.edded into the classical language m.deling fram.work to enhance the prediction of consum.r sentim.nts. The practical im.lication of our research work is that organizations can apply our big data stream.analytics fram.work to analyze consum.rs’ product preferences, and hence develop m.re effective m.rketing and production strategies.

关键词： Big Data Data Stream Analytics Sentim.nt Analysis Online Review

A Sim.larity Law for Stressing Rapidly Heated Thin-Walled Cylinders

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作者： H. S. TSIEN C. m. cheng Daniel and Florence Guggenheim.Jet Propulsion Center. California Institute of Technology Pasadena Calif.

When a thin cylindrical shell of uniform.thickness is very rapidly heated by hot high-pressure gas flowing inside the shell, the tem.erature of m.terial decreases steeply from.a high tem.erature at the inside surface to am.ient tem.eratures at the outside ***’s m.dulus of m.terial thus *** purpose of the present paper is to reduce the problem.of stress analysis of such a cylinder to an equivalent problem.in conventional cylindrical shell without tem.erature gradient in the *** equivalence concept is expressed as a series of relations between the quantities for the hot cylinder and the quantities for the cold cylinder. These relations give the sim.larity law whereby strains for the hot cylinder can be sim.ly deduced from.m.asured strains on the cold cylinder and thus greatly sim.lify the problem.of experim.ntal stress analysis.

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特纳综合征患者血清转化生长因子β的变化

北京大学学报（医学版） 2012年第5期44卷 720-724页

作者：周键 Sruthi AREPALLI Clara m.cheng Vladim.r K.BAKALOV Carolyn A.BONDY Section on Epigenetics&Developm.nt Program on Developmental Endocrinology and GeneticsNational Institute of Child Health and Human DevelopmentNational Institutes of HealthBethesda

目的:观察转化生长因子β(transform.ng growth factor-beta,TGFβ)在特纳综合征(Turner syndrom.,TS)患者血清中的变化及其与内分泌和心血管参数的关系。方法:选择TS患者和健康志愿者妇女(对照组)各40例,采用酶联免疫方法测定血清中的... 详细信息

目的:观察转化生长因子β(transform.ng growth factor-beta,TGFβ)在特纳综合征(Turner syndrom.,TS)患者血清中的变化及其与内分泌和心血管参数的关系。方法:选择TS患者和健康志愿者妇女(对照组)各40例,采用酶联免疫方法测定血清中的TGFβ1、TGFβ2及转化生长因子受体(endoglin)。所有TS患者均行心血管系统磁共振和超声检查。结果:TS患者血清中TGFβ1和endoglin水平均高于对照组(P<0.000 1),而TGFβ2的水平则低于对照组(P<0.000 1)。TGFβ的改变与年龄、血压、血小板、甲状腺功能、体重指数或心血管疾病的分型无关。结论:TS患者血清中TGFβ显著性改变对疾病的研究具有重要意义。

关键词：特纳综合征转化生长因子β 心血管疾病 X染色体主动脉

INITIATION AND PROPAGATION OF SHORT FATIGUE CRACKS IN A WELD m.TAL

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INITIATION AND PROPAGATION OF SHORT FATIGUE CRACKS IN A WELD...

作者： HONG YOUSHI, LU YONGHUA and ZHENG ZHEm.N (C. m. cheng) Institute of m.chanics, Academ.a Sinica, Beijing, China

Fatigue tests were perform.d using a purpose designed triangular shaped specim.n to investigate the initiation and propagation of short fatigue cracks in a weld m.tal. It was observed that short fatigue cracks evolved from.slip bands and were predom.nantly within ferrite grains. As the test progressed, the short crack density increased with m.nor changes in crack length. The growth of short cracks, in the early stage resulted m.inly from.coalescence with other existing cracks. The m.chanism.of short crack behaviour is discussed.

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Developm.nt of Therm.plastic Shear Bands in Sim.le Shear

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Development of Thermoplastic Shear Bands in Simple Shear

作者： Y.-L. Bai, C.-m. cheng and Y.-S. Ding Institute of m.chanics, Chinese Academ. of Sciences, Beijing, China

The developm.nt of therm.plastic shear bands in coupling-rate- and tem.erature-dependent m.terial under sim.le shear is exam.ned, using a sim.lified m.del together with Fourier transform.tion and a m.tching technique at the m.ving boundary of a shear band. The analysis reveals that the developm.nt of a shear band is dom.nated by the coupling rate and tem.erature effect of m.terial. The strength of the m.terial acts as a destabilizer, whilst heat diffusion m.kes the band expand. In addition, shear bands are susceptible to long-wave disturbances and this coincides with instability analysis. A few com.utational exam.les are presented.

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