材料期刊网

THE INFLUENCES OF Zn CONTENT AND COOLING RATE ON ASCAST MICROSTRUCTURE IN Al75% Mg ALLOYS

Q.Wu1)and S.B.Kang2) 1) Department of Material Science and Engineering , Nanjing University of Science and Technology , Nanjing , 210014 , China 2) Department of Material Engineering , Korea Institute of Mechanics and Materials , Changwon , Korea

金属学报(英文版)

Thesolidification processof Al 7 5% Mg Zn alloys wasstudiedin thepaper.The Zn contentand cooling rate werechanged andtheirinfluenceson as cast microstructure were measured by different methods. The solute segregation during nonequilibrium solidification process wascalculated byternary Scheilequation which wasin good agreement with experimentresulte.

关键词: aluminum alloy , null , null

R & D ACTIVITIES ON AEROSPACE MATERIALS IN KOREA

H.M. Kim(Korea Institute of Machinery and Materials , Korea Manuscript received 26 August 1996)

金属学报(英文版)

This paper briefly reviews research and development programs in Korean aerospace industry,with an emphasis on aircraft materials technology. International collaborations in these areas are outlined and the R & D activities are highlighted against the　background of the national economy.It is shown that the investment from government agencies and large enterprises has led to healthy development of aerospace materials industries in Korea.

关键词: :R & D , null , null , null

The tendency of the market and technology of the magnetic materials in Korea

C.O.Kim , Y.Li

材料科学技术（英文）

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The Tendency of the Market and Technology of the Magnetic Materials in Korea

材料科学技术（英文）

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Institute of Materials Science at Jilin University——A Brief Overview

WANG Yuming Institute of Materials Science , Jilin University , Changchun , 130023 , China

材料科学技术（英文）

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THERMAL FATIGUE AND FRACTURE MECHANICS ANALYSIS OF GREY CAST IRON

GUO Chengbi ZHOU Weisheng Dalian Institute of Technology , Dalian , Liaoning , China Professor , Dept.of Shipbuilding , Dalian Institute of Technology , Dalian , Liaoning , China

金属学报(英文版)

The in-phase and out-of-phase thermal fatigue,the C-P type and P-C type isothermal fa- tigue of grey cast iron were experimentally studied.The fatigue life was evaluated analytically by using the elastic-plastic fracture mechanics method(mainly J integral).The results of ex- periments and calculations showed that the lifes of in-phase and C-P type fatigue are longer than that of out-of-phase and P-C type fatigue respectively within the same strain range. This is in contrast to the results of other materials such as low carbon steel.On the other hand, the predicted lifes are consistent with experimental results.This suggests that J integral as a mechanics parameter for characterizing the thermal fatigue strength of grey cast iron and the mechanics model and the calculation method developed here are efficient.A parameter ΔW_1 was proposed from energy aspect to characterize the capacity of crack propagation. The isothermal fatigue life is the same as the thermal fatigue life for identical ΔW_1 values.

关键词: grey cast iron , null , null

Electronic structure analysis of self-consistent embedding theory for quantum/molecular mechanics simulations

Physical Review B

The self-consistent embedding theory provides a rigorous framework for quantum/molecular mechanics simulations of materials. By using crystalline aluminum as an example, we present a critical analysis on the accuracy of the embedding theory, focusing on the electronic structure of the primary quantum mechanics region. We examine the influence of embedding potential on the structural energy, local density of states, total electronic density, and electronic states at the Fermi energy of the primary quantum system. The analysis illustrates the success and limitations of the embedding scheme in describing the electronic structure of the primary quantum region.

关键词: aluminium;density functional theory;electronic density of states;Fermi level;pseudopotential methods;energy-density functionals;wave basis-set;molecular-dynamics;metals;systems

FRACTURE MECHANICS ANALYSIS OF THERMAL STRAIN FATIGUE LIFE FOR THE SINTERING MACHINE PALLET

LI Zhenzi and LI Ming (Department of Architectnre Engineering , Central South University of Technology , Changsha 410083 , China)LIAO Fuchang (Shenzhen School of Technology , Shenzhen 518029 , China)Manuscript received 10 August 1995 , in revised form 12 April 1996

金属学报(英文版)

In recent years elastic-plastic fracture mechanics has developed rapidly and is widely used to solve various engineering problems. The application of elastic-plastic fracture mechanics on the pallet of sintering machine is approached in detail for the first time in the present study. The theoretical results were compared with the actual data determined from sintering machine pallet. Results show that good agreement was achieved between the method suggested by the author and the actual data. The basis of determining design of the sintering machine pallet in iron and steel engineering has been provided and it will result in great economic benefits.

关键词: : pallet , null , null , null

Features and states of microscopic particles in nonlinear quantum-mechanics systems

Frontiers of Physics in China

In this paper, we present the elementary principles of nonlinear quantum mechanics (NLQM), which is based on some problems in quantum mechanics. We investigate in detail the motion laws and some main properties of microscopic particles in nonlinear quantum systems using these elementary principles. Concretely speaking, we study in this paper the wave-particle duality of the solution of the nonlinear Schrodinger equation, the stability of microscopic particles described by NLQM, invariances and conservation laws of motion of particles, the Hamiltonian principle of particle motion and corresponding Lagrangian and Hamilton equations, the classical rule of microscopic particle motion, the mechanism and rules of particle collision, the features of reflection and the transmission of particles at interfaces, and the uncertainty relation of particle motion as well as the eigenvalue and eigenequations of particles, and so on. We obtained the invariance and conservation laws of mass, energy and momentum and angular momentum for the microscopic particles, which are also some elementary and universal laws of matter in the NLQM and give further the methods and ways of solving the above questions. We also find that the laws of motion of microscopic particles in such a case are completely different from that in the linear quantum mechanics (LQM). They have a lot of new properties; for example, the particles possess the real wave-corpuscle duality, obey the classical rule of motion and conservation laws of energy, momentum and mass, satisfy minimum uncertainty re-lation, can be localized due to the nonlinear interaction, and its position and momentum can also be determined, etc. From these studies, we see clearly that rules and features of microscopic particle motion in NLQM is different from that in LQM. Therefore, the NLQM is a new physical theory, and a necessary result of the development of quantum mechanics and has a correct representation of describing microscopic particles in nonlinear systems, which can solve problems disputed for about a century by scientists in the LQM field. Hence, the NLQM built is very necessary and correct. The NLQM established can promote the development of physics and can enhance and raise the knowledge and recognition levels to the essences of microscopic matter. We can predict that nonlinear quantum mechanics has extensive applications in physics, chemistry, biology and polymers, etc.

关键词: microscopic particle;nonlinear systems;nonlinear quantum mechanics;basic principle;motion rule;dynamic property;nonlinear Schrodinger;equation

Approximate means for evaluating tensile strength of high porosity materials

Transactions of Nonferrous Metals Society of China

Based on the simplified structure model of high porosity materials, the formulas for approximately evaluating the tensile strength of these materials have been derived from the corresponding deductions taken by means of the relative theories about geometry and mechanics. The results show that, the tensile strength of these materials not only associates with the material sort and production method, but do further have a direct value relationship with the porosity, theta. This value relationship can be specifically expressed by the power of the item (1 - theta), and it makes the tensile strength variation display a complicated nonlinear law with the porosity. In addition, the application of those formulas has been investigated with the corresponding experiment on a nickel foam.

关键词: high porosity material;tensile strength;evaluation