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A Simulator for Producing of High Flux Atomic Oxygen Beam by Using ECR Plasma Source

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Journal of Materials Science & Technology 2004年第6期20卷 759-762页

作者： Shuwang DUO, Meishuan LI and Yaming ZHANGShenyang National Laboratory for Materials Science, institute of Metal research, Chinese academy of sciences, Shenyang 110016, china Shenyang Natl. Lab. for Mat. Sci. Inst. of Metal Res. Chinese Acad. of Sci. Shenyang 110016 China

In order to study the atomic oxygen corrosion of spacecraft materials in low earth orbit environment, an atomic oxygen simulator was established. In the simulator, a 2.45 GHz microwave source with maximum power of 600 W was launched into the circular cavity to generate ECR (electron cyclotron resonance) plasma. The oxygen ion beam moved onto a negatively biased Mo plate under the condition of symmetry magnetic mirror field confine, then was neutralized and reflected to form oxygen atom beam. The properties of plasma density, electron temperature, plasma space potential and ion incident energy were characterized. The atomic oxygen beam flux was calibrated by measuring the mass loss rate of Kapton during the atomic oxygen exposure. The test results show that the atomic oxygen beam with flux of 1016-1017 atoms-cm-2·s-1 and energy of 5-30 eV and a cross section of φ80 mm could be obtained under the operating pressure of 10-1-10-3 Pa. Such a high flux source can provide accelerated simulation tests of materials and coatings for space applications.

关键词： Atomic oxygen Low earth orbit space environment ECR plasma Microwave

Antisense expression of a rice cellular apoptosis susceptibility gene (OsCAS} alters the height of transgenic rice

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Progress in Natural Science:Materials International 2007年第1期17卷 39-43页

作者： XU Chunxiao and HE Chaozu ( National Key Laboratory of Plant Genomics, institute of Microbiology, Chinese academy of sciences, Beijing 100080, china Graduate University of Chinese academy of sciences, Beijing 100039, china Shenzhen Laboratory of Superhybrid rice research, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, china) National Key Laboratory of Plant Genomics Institute of Microbiology Chinese Academy of Sciences Beijing 100080 China Graduate University Chinese Academy of Sciences Beijing 100039 China Shenzhen Laboratory of Superhybrid rice research Graduate School at Shenzhen Tsinghua University Shenzhen 518055 China

Cellular apoptosis susceptibility (CAS) gene plays important roles in mitosis, development and export of importin a from the nucleus, but its function in plant is unknown. In this study, a rice CAS ortholog (OsCAS), which encodes a predicted protein of 983 amino acids with 62% similarity to human CAS, was identified. DNA gel blot analysis revealed a single copy of OsCAS in the rice genome. A 973 bp fragment at the 3' end of OsCAS cDNA was cloned from rice cDNA library and transferred into rice in the antisense direction under the control of CaMV 35S promoter via Agrobacterium-mediated transformation method, 105 transgenic lines were obtained. Expression of OsCAS was suppressed in the antisense transgenic lines as revealed by semi-quantitative RT-PCR. The antisense transgenic lines showed dwarf phenotypes. The results indicated that OsCAS was involved in culm development of rice.

关键词： antisense dwarf ortholog OsCAS rice.

Effects of Positron Diffusion and Its Application in Composite System

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Journal of Materials Science & Technology 2000年第3期16卷 311-314页

作者： Jian JIANG, Xinzhang ZHOU and ChiWei LUNG (International Center for Materials Physics, institute of Metal research, Chinese academy of sciences, Shenyang 110015, china) International Center for Materials Physics Institute of Metal Research Chinese Academy of Sciences Shenyang 110015 China

The effects of positron diffusion on the measured S parameter have been investigated by a point-source diffusion model and a δ function method. Firstly, the theoretical analyses of the effects are presented for the samples of a homogeneous semi-infinite medium and a film of definite thickness. Then the results are used to analyze the S parameters in several composite systems and interface models.

关键词： Effects of Positron Diffusion and Its Application in Composite System

First-Principles Study of the Polar TiC/Ti Interface

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Journal of Materials Science & Technology 2003年第6期19卷 540-544页

作者： Limin LIU, Shaoqing WANG and Hengqiang YEShenyang National Laboratory for Materials Science, institute of Metal research, Chinese academy of sciences, Shenyang 110016, china Lab. for Mat. Sci. Inst. of Metal Res. Chinese Acad. of Sci. Shenyang 110016 China

The interface structure, work of adhesion, and bonding character of the polar TiC/Ti interface have been examined by the first-principles density functional plane-wave pseudopotential calculations. Both Ti- and C-terminated interfaces including six different interface structures were calculated, which present quite different features. For the Ti-terminated interface, the interfacial Ti-Ti bond has a strong metallic and weak covalent character; while for the C-terminated interface, the interfacial bond is a strong polar covalent interaction between the Ti-3d and C-2p orbital. The work of adhesion of C-terminated interface is nearly 9 J/m2 stronger than that of the Ti-terminated. It is found that each termination has relatively large work of adhesion, which is consistent with other polar interfaces.

关键词： First-principles Metal/ceramic interface Adhesion Carbides

Growth and Microstructure of r.f. Sputtered Fe/Ti Multilayers

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Journal of Materials Science & Technology 2001年第5期17卷 521-524页

作者： Wei WANG Shenyang National Laboratory for Materials Science, institute of Metal research, Chinese academy of sciences, Shenyang 110016, china Lishi WEN Department of Surface Engineering of Materials, institute of Metal research, Chinese academy of Science Shenyang Natl. Lab. for Mat. Sci. Inst. of Metal Res. Chinese Acad. of Sci. Shenyang 110016 China

Fe/Ti multilayers with different modulation wavelengths (Lambda) prepared by r.f. sputtering has been investigated by using cross sectional transmission electron microscopy (XTEM). It was observed that the columnar structure, interface morphology, and metastable phase presented at the interface of the multilayer system strongly depend on the bilayer thickness (Lambda). For high period multilayers, the waviness wavelength of interfaces is about two times broader than the column diameter. For a sample with Lambda =30 nm, its column width and waviness wavelength was about 80, and 190 nm, respectively. Both of them decreased with the reduction of Lambda, so as to nearly equal values of column diameter and waviness wavelength were obtained. The Fe and Ti grains of both 30 nm and 6 nm multilayers are polycrystalline, and have a textured structure. In short bilayer thickness (Lambda =6 nm), the intermetallic compound Fe2Ti was presented at the interfaces due to solid state reaction; for Lambda =2 nm, amorphous phase Ti-rich layer was formed at the interfaces, resulting in a sharp interface multilayer structure.

关键词： Ti Growth and Microstructure of r.f Sputtered Fe/Ti Multilayers Fe

Emission of landfill gas in Qingdao, china

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Journal of Environmental sciences 1996年第3期8卷 292-297页

作者： Gao Jixi Shen Yingwa Cao Hongfa Shu Jianmin(institute of Ecology, Chinese research academy of Environmental sciences,Beijing 100012, china) institute of Ecology Chinese Res. Acad. of Environ. Sci. Beijing 100012 China

A study on landfill gas emission in Qingdao,china was carried out. The results showed that the generation of landfill gas with maximum methane concentration occurred several months after the refuse was disposed and the steady emission of landfill gas could remain two *** variation of landfill gas production was associated with temperature. In June, the emission of landfill gas rose gradually from morning to evening, but in September, it rose in the morning, and then fell in the afternoon. From June to August, the emission of landfill gas showed rising trend,but it declined quite quickly from September to December. In different seasons,the outflow rate of landfill gas varied from depth to depth in the refuse site. When earth temperature was higher in summer, the emission of landfill gas did not correspond with the depth of refuse sites, but when temperature fell in winter, and the temperature became a limited factor to the gas production,the outflow of landfill gas increased with increasing in depth of refuse piling.

关键词： landfill gas emission china

Oxidation Behavior of C/C-SiC Gradient Matrix Composites

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Journal of Materials Science & Technology 2001年第5期17卷 543-546页

作者： Jingyi DENG, Wenchuan LIU, Haifeng DU, Huiming CHENG and Yiyi LI institute of Metal research, Chinese academy of sciences, Shenyang 110016, china Inst. of Metal Res. Chinese Acad. of Sci. Shenyang 110016 China

Oxidation behavior of C/C-SiC gradient matrix composites and C/C composites were compared in stationary air. The results show that oxidation threshold of C-SiC materials increases with the amount of SiC particles in the codeposition matrix. Oxidation rate of C/C-SiC gradient matrix composites is significantly lower than that of C/C material. The micro-oxidation process was observed by SEM.

关键词： Oxidation Behavior of C/C-SiC Gradient Matrix Composites SiC SIC

The Assessment and Utilization of Straw Resources in china

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agricultural sciences in china 2010年第12期9卷 1807-1815页

作者： WANG Ya-jing, BI Yu-yun and GAO Chun-yu institute of agricultural Resources and Regional Planning, Chinese academy of agricultural sciences, Beijing 100081, P.R.china institute of agricultural Resources and Regional Planning Chinese Academy of Agricultural Sciences Beijing 100081 P.R.China

The study was undertaken to evaluate the collectable and usable volume of existing straw resources, its suitability for different ways of utilization and fully reorganization of its development potential in china. Based on the results on the stubble heights of major crops in the Huang-Huai-Hai area （the area along the Yellow River, Huai River, and Hai River）, the evaluation of the collectable and usable coefficients, and the collectable and usable volumes of various straw resources in china were worked out during 2005. The respective collectable and usable volumes of straw resources were worked out on the basis of suitability as fuel, feed, fertilizer, and base material for edible mushrooms. The total collectable and utilizable quantity of straw in china was 685 950 000 t, and the mean collection coefficient was 0.81 during 2005. The quantity of straw residue and wasted straw accounted for 19%. The collectable and utilizable quantities of grain, cash crop, and other crop straw were 492 310 000, 162 610 000, and 31 030 000 t which accounted for 71.77, 23.71, and 4.52%, respectively of the total collectable and utilizable quantity of straw. The quantity of straw which could be used as fuel was 635 000 000 t, which accounted for 92.63% of total quantity of the straw in the country during 2005. Among the total quantity of collectable and utilizable straw in china during 2005, the quantities of straw suitable and unsuitable for being processed as feedstuff were 587 640 000 and 98 310 000 t, which accounted for 85.67 and 14.33%, respectively. The quantity of straw residue returned to the field and collectable and utilizable straw for direct field restoration was 616 000 000 t, which accounted for about three-fourths of the total straw yield, while the quantity of straw for cultivation of edible mushrooms and industrial processing was about 587 000 000 t, which accounted for more than 85% of the total collectable and utilizable straw. The evaluation results indicate that t

关键词： china straw resources collectable and utilizable quantity suitability assessment

Regional differences and determinants of built-up area expansion in china

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Science china Earth sciences 2007年第12期50卷 1835-1843页

作者： HUANG JiKun1,2,ZHU LiFen3,1 & DENG XiangZheng1,2 1 Center for Chinese agricultural Policy,Chinese academy of sciences,Beijing 100101,china 2 institute of Geographic sciences and Natural Resources research,Chinese academy of sciences,Beijing 100101,china 3 research Center of the Economy of the Upper Reaches of the Yangtze River,Chongqing Technology and Business University,Chongqing 400067,china Center for Chinese agricultural Policy Chinese Academy of Sciences Beijing China institute of Geographic sciences and Natural Resources research Chinese Academy of Sciences Beijing China research Center of the Economy of the Upper Reaches of the Yangtze River Chongqing Technology and Business University Chongqing China

Based on remote sensing data on land use provided by the Chinese academy of sciences and socio-economic data collected by the authors,this paper analyzes the trends and regional differences in built-up area(BUA) expansion in china from the late 1980s to 2000,and empirically estimates the major determinants of BUA expansion in different regions in 1996―*** 1989―2000,although china's overall BUA expansion accelerated,the trends differed significantly among *** expansion in the central and western regions accelerated significantly,but it slowed down considerably in the east-ern *** estimation results from our econometric analysis reveal that BUA expansion in the eastern region reached a period when economic growth had no further significant impact on per capita BUA,the land utilization in this region has become more intensive with further expansion of the *** the central and western regions,the BUA has expanded remarkably due to the relatively more flexible land development policies and the relatively cheap land ***,as the econ-omy continues to grow rapidly,policies relating to BUA expansion and cultivated land reductions may face more serious challenges in the central and western regions.

关键词： built-up area, land use, regional difference, determinants, china