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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

Consolidation and Compression Property of Nanocrystalline NiAl Synthesized by Mechanical Alloying

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Journal of Materials Science & Technology 1996年第1期12卷 7-10页

作者： Liu, ZG guo, jt Shi, NL Hu, ZQ State Key Lab. for RSA Institute of Metal Research Chinese Academy of Sciences Shenyang 110015 China

The mixture of pure nickel and aluminum powders in the composition of Ni50Al50 was subjected to high energy ball milling. The high energy ball milling to 30 h resulted in the formation of a nanocrystalline NiAl with a grain size of about 10 nm. The as-milled NiAl powder was hot-pressed and the compact with a density of 90% was obtained. It was showed that heating to 900 degrees C and holding for more than 2 h failed to induce the coarsening of the fine nanocrystal in the material, the tendency of grain growth was weak. Compression testing showed that the compression ductility at room temperature reached about 7%. The ductility increased with the experimental temperature while the strength decreased drastically at elevated temperature.

关键词： Nickel alloys

Influence of Fe on electronic density of defects in NiAl alloys

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Chinese Science Bulletin 1997年第21期42卷 1783-1787页

作者： Deng, W Xiong, LY Wang, SH guo, jt Long, QW Guangxi Univ Dept Phys Nanning 530004 Peoples R China

NiAl alloy is considered to be a good candidate material for high performance, high-tempera-ture structural applications since this material offers a wide range of attractive mechanical andphysical properties, such as low density (5. 86 g/cm^3), high melting point (1 640℃), goodthermal conductivity (4--8 times compared with Ni-based superalloys) and oxidation resis-tance. However, the use of NiAl is limited by its room-temperature brittleness. Georgeand Liu have investigated the effects of microalloying elements B, C and Be on the fractureproperties and grain boundaries of NiAl alloy. Their results showed that the improvement

关键词： NiAl alloy positron lifetime microdefects electronic density.

Molecular dynamics simulation of quartz deformation under slow earthquake background

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Science China Earth Sciences 2025年

作者： Jingxian SUN Qianqian guo Quanlin HOU College of Earth and Planetary Sciences University of Chinese Academy of Sciences Key Laboratory of Computational Geodynamics CAS

Slow earthquakes are the primary mechanism of slow energy release, and research on the focal mechanism has been inconclusive. Studies have primarily focused on the friction law based on physical mechanisms and have suggested that slow earthquakes are caused by brittle faults. However, the focal strength and structural characteristics of slow earthquakes in subduction zones provide evidence of plastic deformation. What is the role of plastic deformation in the focal mechanisms of slow earthquakes? Mechanochemical study have shown that mechanical forces can directly affect chemical bonds. In this study,we examine the storage and release of chemical energy during plastic deformation and consider a mechanochemical process in the focal mechanism of slow earthquakes. Combined with the Tersoff potential, molecular dynamics simulation on the shear deformation process of two α-quartz crystals show that the shear modulus of α-quartz is 18 GPa, and that the crystal model primarily exhibits atoms flowing and changing in the direction of chemical bonds during the steady-state flow stage. The molecular potential energy and stress vary in an oscillating up-and-down curve during shear, indicating that chemical energy can be stored and released during plastic deformation. This is consistent with the energy variation during slow earthquakes. Under the initial simple-shear loading condition, α-quartz crystals undergo general shear deformation instead of plane strain and the angle between the longest instantaneous stretching axis （ISA1） and the shearing direction is approximately 30°, not 45°. Both the deformation type and direction of ISA1are contrary to basic deformation theory, which may provide clues for future *** study reveals the process of quartz elastic-plastic shear deformation on an atomic scale. This information is useful for understanding focal mechanisms of slow earthquakes. This study is part of a series of investigations on tectonic stress chemistry.

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Results and Future Plan of jt-60U towards Steady-State Tokamak Reactor

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Plasma Science and Technology 2004年第1期6卷 2151-2158页

作者： S.Sakurai the jt-60 Team Japan Atomic Energy Research Institute Naka Ibaraki 311-0193 JapanJapan Atomic Energy Research Institute Naka Ibaraki 311-0193 Japan

Recent results of jt-60U towards establishment of physics basis for ITER andadvanced tokamak operation are presented. Progress in high integrated performance is achieved withimprovement of N-NB and ECRF heating systems. In the next experimental campaign 2003～2004,discharge duration with 17 MW heating will be extended up to 30s for sustaining high-beta plasmalonger than the current diffusion time. Superconducting modification of jt-60 is planned todemonstrate high-beta plasma sustainment exceeding ideal MHD instability limit without wallstabilization.

关键词： jt-60U confinement study steady-state operation high confinement plasma plan and future plan

Present Status of jt-60SA Project and Development of Heating Systems for jt-60SA

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Plasma Science and Technology 2011年第3期13卷 367-375页

作者： Yoshitaka IKEDA jt-60SA Team Japan Atomic Energy Agency 801-1 Mukoyama Naka Ibaraki 311-0193 Japan

Present status of the jt-60SA （jt-60 Super Advanced） project, implemented jointly by Europe and Japan since 2007, is described. The design of the main tokamak components was completed in late 2008, and all the scientific missions are preserved to contribute to ITER and DEMO reactors. The construction of the jt-60SA has begun with procurement activities for the superconducting magnet systems, vacuum vessel, in-vessel components and other components under the relevant procurement arrangements between the implementing agencies of JAEA （Japan Atomic Energy Agency） in Japan and Fusion for Energy in Europe. Designs and developments of the auxiliary heating systems for jt-60SA have been progressing at JAEA so as to provide the total injection power of 41 MW for 100 s.

关键词： jt-60SA ITER DEMO JAEA heating systems

Binderless Carbon/Graphite Materials

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Journal of Materials Science & Technology 1997年第3期13卷 184-188页

作者： Zhou, SM Xia, jt Yan, LC Dept. of Chemistry and Chemical Engineering Hunan University Changsha 410082 China

High performance binderless carbon bodies can be manufactured from the mesophase raw material derived from petroleum pitch, which is ground into fine powders less than 10 mu m, and directly moulded, then sintered at 1000 degrees C without any kind of binder. The sintered bodies have a bulk density of 1.69 g/cm(3), bending strength of 91.2 MPa. Shore hardness of 100, porosity of only 7.2%, and electrical resistivity of 60x10(-6) Omega m. The bodies graphitized at 2800 degrees C have a bulk density of 1.88 g/cm(3), bending strength of 82 MPa. Shore hardness of 85, porosity of 5.4%, and electrical resistivity of 12x10(-6) Omega m. The scanning electron micrographs of the section show that the bodies possess an extremely dense and homogeneous structure. Infra-red spectrum analysis shows that carbonyls introduced when ground or activated are one of the key factors determining the selfbinding and selfsintering properties of the mesophase fine powders, and the structure and strength of the sintered bodies.

关键词： Carbon

Influence of oscillator phase on oscillation frequency and sensitivity of an electrode-separated piezoelectric sensor

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Chinese Journal of Chemistry 1996年第3期14卷 235-243页

作者： Shen, DZ Kang, Q Hu, jt SHANDONG UNIV CHEM COLLJINAN 250100SHANDONGPEOPLES R CHINA

Theoretical consideration was proposed for the influences of the oscillator phase on the response nature of an electrode-separated piezoelectric sensor (ESPS) to liquid properties and verified experimentally. For the oscillators with different phases, the oscillation frequency of the ESPS may increase, maintain nearly constant or decrease with increasing conductivity in low conductivity solutions. The sensitivity of response to density and viscosity increases slightly with increasing oscillator phase. The response to permittivity depends hardly on the oscillator phase. In addition, the dependence of the oscillation frequency of the ESPS on the supply voltage of the oscillator was explained. The ESPS was used to determine atropine sulfate with a detection limit of 1.6x10(-7) mol/L.

关键词： piezoelectric sensor oscillator phase oscillation frequency liquid properties

Synthesis and Luminescence Properties of Barium Fluorotungstate Phosphors

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Chinese Chemical Letters 1997年第7期8卷 643-644页

作者： Yang, SJ Sun, jt Qin, ZB HUBEI NORMAL UNIV DEPT CHEMHUNGSHI 435002PEOPLES R CHINA WUHAN UNIV DEPT CHEMWUHAN 430072PEOPLES R CHINA

The investigation of the system BaF2-WO3 revealed the existence of a fluoro-tungstate formulated as Ba2WO3F4. The Ba2WO3F4 was prepared with the solid state reaction method. Under UV or X-ray excitation, Ba2WO3F4 exhibits a very strong blue-green emission peaking at 480 nm at room temperature. The luminescence properties are similar to those of the tungstate, especially MgWO4. The luminescence and energy transfer of tungstates are well known for a long time and was reviewed by Blasse([1]). But barium tungstate show only weak luminescence even down to liquid helium temperature([2]). We were surprised to find that Ba2WO3F4 is an efficient phosphor which can be practically used. In this paper, the preparation method and luminescence properties of Ba2WO3F4 phosphor were investigated. The relationship between the luminescent properties and crystal structure was discussed.

关键词： Ba nm

DIFFUSION WELDING FOR 6061 Al REINFORCED WITH SiCw WHISKER

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Journal of Wuhan University of Technology(Materials Science) 1999年第1期14卷 1-5页

作者： Niu, jt Liu, LM Han, LH Harbin Inst Technol Sch Mat Sci & Engn Harbin 150001 Peoples R China

The weldability of SiCw/6061Al -was investigated. From the results of experiments, it is found that the strength of joint is mainly influenced by welding temperature, and high strength of joint is obtained under melding temperature between liquidus and solidus of matrix alloy. Diffusion welding of SiCw/6061Al was successfully realized with appropriate ivelding parameters.

关键词： SiCw/6061Al composite diffusion welding welding temperature