检索结果-南通市图书馆

Design of policy mechanism to promote cleaner production in china

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2001年第3期13卷 346-350页

作者： ZHANG Tian zhu(Department of Environmental Science and engineering, tsinghua university, {2., china. Department of Environmental Science and engineering Tsinghua University Beijing 100084 China. zhangtz@***

In order to promote cleaner production in china, a package of policy options was presented based on the identification of the barriers encountered in the CP demonstration project and the effectiveness and feasibility of policy options for the CP implementation were analyzed. Furthermore, the policy mechanism framework was given, which composes of compulsory, economic incentive, social pressure and supportive function. Finally, the implementation strategy of the policy mechanism, in which the emphasis will be changed from compulsory policy options towards economic and social pressure policy options, was proposed.

关键词： cleaner production barrier identification policy mechanism china

Finite Element Simulation for Interfacial Evolutions

在线全文

学校读者我要写书评

暂无评论

Communications in Nonlinear Science and Numerical Simulation 1998年第2期3卷 3-5页

作者： Jianming HUANG and Wei YANG (Department of engineering mechanics, {2., beijing 100084, china) E mail: yw dem@*** Department of engineering mechanics Tsinghua University Beijing 100084 China

ＩｎｔｒｏｄｕｃｔｉｏｎＩｎｔｅｒｆａｃｅｍｏｔｉｏｎｐｌａｙｓａｄｅｃｉｓｉｖｅｒｏｌｅｉｎｄｅｓｉｇｎｉｎｇｔｈｅｍｉｃｒｏｓｔｒｕｃｔｕｒｅ，ｆａｂｒｉｃａｔｉｎｇｍａｔｅｒｉａｌｓ，ａｎｄｓｈａｐｉｎｇｔｈ... 详细信息

ＩｎｔｒｏｄｕｃｔｉｏｎＩｎｔｅｒｆａｃｅｍｏｔｉｏｎｐｌａｙｓａｄｅｃｉｓｉｖｅｒｏｌｅｉｎｄｅｓｉｇｎｉｎｇｔｈｅｍｉｃｒｏｓｔｒｕｃｔｕｒｅ，ｆａｂｒｉｃａｔｉｎｇｍａｔｅｒｉａｌｓ，ａｎｄｓｈａｐｉｎｇｔｈｅｓｔｒｕｃｔｕｒｅｇｅｏｍｅｔｒ...

关键词： finite element scheme energetics and kinetics interface motion

HIGH ACCURACY NUMERICAL METHOD OF THIN-FILM PROBLEMS IN MICROMAGNETICS

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Computational Mathematics 2003年第1期21卷 33-40页

作者： Zhongyi Huang (Deft, of Mathematical Sciences, tsinghua university, beijing, {2., china) Dept. of Mathematical Sciences Tsinghua University 北京 100084

In this paper, a new high accuracy numerical method for the thin-film problems of micron and submicron size ferromagnetic elements is proposed. For the computation of stray field, we use the finite element method(FEM) by introducing a semi-discrete artificial boundary condition [1, 2.. In our numerical experiments about the domain patterns and their movement, we can see that the results are accordant to that of experiments and other numerical methods. Our method are very convenient to deal with arbitrary shape of thin films such as a polygon with high accuracy.

关键词： Thin-film Micromagnetics stray field Semi-discrete artificial boundary condition.

Coacervate Structures of CdI_2.Thin Film Grown during Phase Transformation

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 1997年第4期13卷 296-298页

作者： Xiaoyan YE and Lili CAO(Dept. of Chemistry, tsinghua university, beijing 100084, {2.)Jizhong ZHANG and Hengde LI(Dept. of Materials Scieuce & engineering, tsinghua university, beijing 100084, {2.) Dept. of Chemistry Tsinghua University Beijing 100084 China Dept. of Materials Science and engineering Tsinghua University Beijing 100084 China

The microstructure of CdI2.thin film grown during vapor-phase deposition was investigated by scanning electron microscopy (SEM). The thin film deposited on Si crystal consists of numerous sunflower-like aggregates. These aggregates display well self-assembly characteristics. The size of Sunflower-like aggregates is between 12.and 44 μm. Each sunflower-like aggregate is surrounded with many adjacent wings-'petals'. The structure of central region of the 'sunflower' is obviously difFerent from that of the 'petal'. Electron spectroscopy for chemical analysis (ESCA) was employed in determining the chemical valence of the thin film. Self-organization efFect is used to explain the coring growth process of CdI2.thin film

关键词： Thin Coacervate Structures of CdI2.Thin Film Grown during Phase Transformation

A molecular dynamics study on melting point and specific heat of Ni_3Al alloy

在线全文

学校读者我要写书评

暂无评论

Science china(Physics,mechanics & Astronomy) 2007年第4期50卷 407-413页

作者： YANG Hong,Lü YongJun,CHEN Min & GUO ZengYuan Department of engineering mechanics,{2.,beijing 100084,china 1. Department of engineering mechanics Tsinghua University Beijing 100084 China

Using the Embedding Atom Method(EAM)for highly undercooled Ni3Al alloy,the melting point and the specific heat were studied by a molecular dynamics *** simulation of melting point was carried out by means of the sandwich method and the NVE ensemble method,and the results show a good agreement,whereas are larger than the experimental value of 1663 *** difference is attrib-uted to the influence of surface melting on experimental results,which causes the smaller measurements compared with the thermodynamic melting *** simulated specific heat of Ni3Al alloy weakly and linearly increases with the in-crease of undercooling in the temperature range from 800 K to 2.00 K.

关键词： Ni3Al alloy undercooled melting point specific heat

Stability　Analysis　of　Nonlinear　Vibrations　of　a　Deploying　Flexible　Beam

在线全文

学校读者我要写书评

暂无评论

Communications in Nonlinear Science and Numerical Simulation 1996年第4期1卷 32-35页

作者： Junfeng LI & Zhaolin WANG (Department of engineering mechanics, {2., beijing 100084,china) E-mail: lijf@*** Department of engineering mechanics tsinghua university beijing 100084 china

ＳｔａｂｉｌｉｔｙＡｎａｌｙｓｉｓｏｆＮｏｎｌｉｎｅａｒＶｉｂｒａｔｉｏｎｓｏｆａＤｅｐｌｏｙｉｎｇＦｌｅｘｉｂｌｅＢｅａｍ１，２１ＰｒｏｊｅｃｔｓｕｐｐｏｒｔｅｄｂｙｔｈｅＮａｔｉｏｎａｌＮａｔｕｒａｌＳｃｉｅｎｃ... 详细信息

ＳｔａｂｉｌｉｔｙＡｎａｌｙｓｉｓｏｆＮｏｎｌｉｎｅａｒＶｉｂｒａｔｉｏｎｓｏｆａＤｅｐｌｏｙｉｎｇＦｌｅｘｉｂｌｅＢｅａｍ１，２１ＰｒｏｊｅｃｔｓｕｐｐｏｒｔｅｄｂｙｔｈｅＮａｔｉｏｎａｌＮａｔｕｒａｌＳｃｉｅｎｃｅＦｏｕｎｄａｔｉｏｎｏｆＣｈｉｎ...

关键词： Deploying flexible beam Rigid-flexible coupled system Partial stability

MICROMECHANICAL MODELLING OF STRAIN SOFTENING IN MICROCRACK-WEAKENED QUASI-BRITTLE MATERIALS

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Acta Mechanica Solida Sinica 1995年第2期8卷 121-132页

作者： Feng Xiqiao Yu Shouwen(Dept.of engineering mechanics,{2.,beijing 100084,P.R.china) Dept. of engineering mechanics Tsinghua University Beijing 100084 China

By using the concept of domain of microcrack growth(DMG),the micromechanisms of damage in quasi-brittle materials subjected to triaxial either tensile or compressive loading are investigated and the complete strew-strain relation including four stages is obtained from micromechanical *** regime of pre-peak nonlinear hardening corresponds to the distributed damage,*** stable propagation of *** the attainment of the ultimate strength of load-bearing capacity, some microcracks experience the second unstable growth and the distributed damage is transmitted to the localization of *** analyses improve our understanding of the hardening and softening behaviors of quasi-brittle materials.

关键词： microcracks strain softening constitutive relation micromechanical damage mechanics brittle material

Parameter estimation for whole-body kinetic model of FDG metabolism

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2006年第11期16卷 1164-1170页

作者： CUI Yunfeng~1, BAI Jing~1**, CHEN Yingmao~2.and TIAN Jiahe~2.1. Department of Biomedical engineering, tsinghua university, {2., china 2. Department of Nuclear Medicine, General Hospital of PLA, beijing 100853, china) [a]Department of Biomedical engineering Tsinghua University Beijing China [b]Department of Nuclear Medicine General Hospital of PLA Beijing China

Based on the radioactive tracer [ ~ 18 F]2.fluoro-2.deoxy-D-glucose （FDG）, positron emission tomography （PET）, and compartment model, the tracer kinetic study has become an important method to investigate the glucose metabolic kinetics in human body. In this work, the kinetic parameters of three-compartment and four-parameter model for the FDG metabolism in the tissues of myocardium, lung, liver, stomach, spleen, pancreas, and marrow were estimated through some dynamic FDG-PET experiments. Together with published brain and skeletal muscle parameters, a relatively complete whole-body model was presented. In the liver model, the dual blood supply from the hepatic artery and the portal vein to the liver was considered for parameter estimation, and the more accurate results were obtained using the dual-input rather than the single arterial-input. The established whole-body model provides the functional information of FDG metabolism in human body. It can be used to further investigate the glucose metabolism, and also be used for the simulation and visualization of FDG metabolic process in human body.

关键词： compartment model FDG PET parameter estimation.

SOME PROPERTIES OF LSQR FOR LARGE SPARSE LINEAR LEAST SQUARES PROBLEMS

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Systems Science & Complexity 2010年第4期23卷 815-821页

作者： Zhongxiao JIA Department of Mathematical Sciences,tsinghua university,beijing 100084,{2.. Department of Mathematical Sciences Tsinghua University

It is well-known that many Krylov solvers for linear systems,eigenvalue problems,andsingular value decomposition problems have very simple and elegant formulas for residual *** not only allow us to further understand the methods theoretically but also can be usedas cheap stopping criteria without forming approximate solutions and residuals at each step beforeconvergence takes *** for large sparse linear least squares problems is based on the Lanczosbidiagonalization process and is a Krylov ***,there has not yet been an analogouslyelegant formula for residual *** paper derives such kind of *** addition,the authorgets some other properties of LSQR and its mathematically equivalent CGLS.

关键词： CGLS krylov subspace lanczos bidiagonalization least squares lsqr normal equations.