检索结果-南通市图书馆

Journal of Materials science & Technology 1998年第4期14卷 331-334页

作者： Jiang, DT Guo, JT chinese acad sci Inst Met Res Shenyang 110015 Peoples R China

A novel in-situ multiphase NiAl-based composite was investigated on its microstructures and properties influenced by HIP treatment. In the as- processed composites, a fine array of NiAl precipitates was found to be distributed in Cr(Mo) phase. TiC particles tended to segregate at grain or phase boundaries. In addition, a number of dislocations were observed to exist in NiAl grains meanwhile fewer in Cr(Mo) grains. Little change in the morphology was found except that nearly fully densification was achieved. Some changes in microstructures were notable including coarsening of NiAl precipitates in Cr(Mo) phase and increase in dislocation density in NiAl phase. After HIP, the strength of the composites increased significantly compared with the as-processed composites. The reason for the enhanced strength of the composites is also discussed.

关键词： Metallic matrix composites

Investigation on the computation of atomic multipole moments with the modified cumulative potential-derived semiempiricalmethod

在线全文

学校读者我要写书评

暂无评论

chinese Journal of Chemistry 1997年第6期15卷 481-491页

作者： Xu, LJ Zhu, CB Yan, JM chinese acad sci Inst Chem Beijing 100080 Peoples R China

The suitability of calculating atomic multipole moments from AM1 wave functions by cumulative potential-derived method has been investigated. It is shown that this method has a faster convergence of the fitting process and gives a better description of the charge distribution than the original PD method. Atomic charges obtained in this way are of comparable quality with 6-31G* data and the calculated dipole moments are closer to the experimental data than the values computed directly from the AM1 charges. The results demonstrate that the atomic multipole moments higher than monopole moment can be used to supplement the atomic charge to obtain a more accurate description of charge distribution. For the sake of comparison, both the Williams fitting potential surface and the Connolly one are used in the calculation.

关键词： atomic charge atomic multipole moment cumulative fitting AM1

Calibration and Experimental Research of a Multiple-wavelength Flame Temperature Instrumentation System

在线全文

学校读者我要写书评

暂无评论

Journal of Thermal science 2004年第4期13卷 371-375页

作者： Zhihong Li Shi Liu Huaiping Mu Fan Jiang Jianmin Guo chinese acad sci Inst Engn Thermophys Beijing 100080 Peoples R China

This paper presents a study on a novel instrumentation system for the measurement of temperature distribution of combustion flames. This system operates upon the three-color principle combining advanced optical sensing and digital image processing techniques. It comprises an endoscope, a light splitter assembly, a CCD camera, a frame-grabber and associated software. This system was calibrated using a blackbody furnace as standard temperature source. The relationship between flame temperatures and grey-level of the images was established through image processing and function correlation. Experimental results obtained on a gas-fired combustion rig provide flame images and temperature distributions on three different wavelengths. Based on the flame temperature distribution the combustion conditions can be analyzed. Experimental results also reveal that this system is capable of online measurement of temperature distribution in a combustion zone. This system can potentially be applied to many areas such as power generation, metallurgy, chemical engineering. It is also a powerful tool for improving the control of combustion process. Keywords three-color method - flame monitor - temperature - imaging processing CLC number TK311

关键词： three-color method flame monitor temperature imaging processing

Tensile Creep Behaviour of Silicon Carbide Particulate Reinforced Aluminium Composite

在线全文

学校读者我要写书评

暂无评论

Journal of Materials science & Technology 1998年第1期14卷 33-36页

作者： Ma, ZY Bi, J Lu, YX chinese acad sci Inst Met Res Shenyang 110015 Peoples R China

Tensile creep tests were carried out on 15SiC (***) particulate reinforced commercial pure aluminum (15%SiCp/Al) composite at 573 and 623 K. The steady state creep stage exists at the applied stresses under the condition of tension. The 15%SiCp/Al composite exhibits an apparent stress exponent of about 13 and an apparent activation energy of 253 kJ/mol. The creep data were normalized using a substructure invariant model with a stress exponent of 8 together with a threshold stress.

关键词： Metallic matrix composites

Study on Current-Random Wave Forces Acting on a Framework

在线全文

学校读者我要写书评

暂无评论

China Ocean Engineering 1998年第3期13卷 265-274页

作者： E, XQ Shao, CP Gao, YX chinese acad sci Inst Mech Beijing 100080 Peoples R China

The forces of random wave plus current acting on a simplified offshore platform (jacket) model have been studied numerically and experimentally. The numerical results are in good agreement with experiments. The mean force can be approximated as a function of equivalent velocity parameter and the root-mean-square force as a function of equivalent significant wave height parameter.

关键词： random wave wave forces current condition jacket framework

Step Sintering of Microwave Heating and MicrowavePlasma Heating for Alumina Ceramics

在线全文

学校读者我要写书评

暂无评论

Journal of Materials science & Technology 1999年第5期15卷 419-422页

作者： Zhang, JS Cao, L Yang, YJ Diao, YX Shen, XX chinese acad sci Met Res Inst Shenyang 110015 Peoples R China

The invention of microwave induced plasma during microwave heating makes it possible to confine plasma inside a crucible, in the pressure range of 1.33 Pa to 0.5 MPa, and above 900 degrees C. In this study, the step sintering of microwave heating and microwave plasma heating (SSMP) was proposed. In this process, microwave heating and plasma heating was ingeniously combined in one chamber, and vacuum was unnecessary for microwave induced plasma. In the first step, the microwave energy directly heated alumina ceramics to a given temperature, above which microwave will mainly ionize the gas and sustain a plasma. Then the plasma further heated alumina ceramics to the final temperature to finish sintering. Maintaining the advantages of microwave heating and plasma heating, this step sintering approach will overcome the limitation of both processes for processing ceramics, and it will be suitable for sintering all kinds of ceramics in principle.

关键词： Ceramic materials

Substitution Behavior of Elements in CoZr-with Consideration of Lattice Relaxation

在线全文

学校读者我要写书评

暂无评论

Journal of Materials science & Technology 1999年第4期15卷 366-368页

作者： Xu, DS Li, D Hu, ZQ chinese acad sci Inst Met Res Shenyang 110015 Peoples R China

The substitution behavior of some alloying elements in CoZr is investigated using the discrete variational X alpha cluster method. The method proposed by the author to predict the substitution behavior is amended to consider the local lattice relaxation. A diagram is drawn based on the binding energies of clusters with alloying elements taking either Co or Zr site. Two straight lines on the diagram separate the alloying elements into three groups with different substitution behavior. The elements above the upper line will take Zr sites and those below the lower line will take Co sites regardless of the composition. The substitution behavior of elements in between the two lines will be affected by the alloy composition. The concept of site competition and step ordering is proposed.

关键词： Intermetallics

Some Regularities of Continuous Solid Solutions of Alloy Systems

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5期13卷 431-434页

作者： Guo, JK Li, CH Qin, P Liu, HL Chen, NY chinese acad sci SHANGHAI INST METSHANGHAI 200050PEOPLES R CHINA

A modified Miedema model and pattern recognition technique are used to establish the criteria for the formation of continuous solid solutions in alloy systems, and to study the occurrence of the melting temperature mi... 详细信息

关键词： Binary alloys

Factors Affecting Terminal Solid Solubility in Alloy Systems

在线全文

学校读者我要写书评

暂无评论

Journal of Materials science & Technology 1998年第3期14卷 277-280页

作者： Guo, Jingkang Su, Hang Li, Chonghe Chen, Nianyi chinese acad sci Shanghai Inst Met Shanghai 200050 Peoples R China

Pattern recognition method was applied to investigate the factors affecting the terminal solid solubility in binary alloy systems. It has been found that the atomic volume, the valence electron number and the melting point of the solute elements exhibit good correlation with the terminal solid solubility. (Edited author abstract) 7 Refs.

关键词： Binary alloys

Microstructure Studies of GaInAsSb/GaSb Heterostructure

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2000年第1期19卷 34-38页

作者：张子旸李树玮张宝林周天明蒋红金亿鑫 chinese acad sci Changchun Inst Phys Changchun 130021 Peoples R China

The preliminary results of scanning transmission electron microscope investigations on the interface of GaInAsSb/GaSb heterostructure were presented. STEM images show that the various dislocations and stacking faults were produced by the lattice mismatch between the quaternary GaInAsSb alloy and GaSb substrates. All these defects were the ways for relieving the misfit strain, including 60° dislocation, 90° dislocation and stacking faults. It is also found that only the 90° dislocation can form the ridges on the surface of the epilayer.

关键词： Dislocation Stacking fault STEM GaInAsSb