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Study on H atoms diffusion and adsorption properties of MgH_2-V systems

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science china(Technological sciences) 2008年第7期51卷 979-988页

作者： ZHOU DianWu1,2, LIU JinShui3.& PENG Ping3.1 State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body, Hunan university, Changsha 410082, china 2 college of Mechanical and Automatic Engineering, Hunan university, Changsha 410082, china 3.college of Materials science and Engineering, Hunan university, Changsha 410082, china 1. State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body Hunan University Changsha 410082 China 2. college of Mechanical and Automatic Engineering Hunan University Changsha 410082 China 3. college of Materials science and Engineering Hunan University Changsha 410082 China

Based on experimental results that VH0.81/MgH2 interface was found during the process of mechanically milling MgH2+5at.%V nanocomposite, H atoms diffusion and adsorption properties of MgH2-V systems have been investigated by using a first-principles plane-wave pseudopotential method based on the density functional theory. The results are as follows. When VH/MgH2 interface is formed due to V alloying MgH2 phase, the vacancy formed by H atoms near VH phase region is more stable than that without V alloying, while vacancy near MgH2 phase region is less stable than that without V alloying. During the process of H atoms diffusion after V alloying, the max migration barrier energy of H atoms in MgH2-V systems is reduced compared with that of MgH2 phase, which means that H atoms diffuse easily. When H diffuses into VH from MgH2 across VH/MgH2 interface, among three substitutions such as the replacement of H for V vacancy, or interstitial site or V atoms, the replacement of H for V vacancy has the strongest diffusion ability, next interstitial site, and finally V atoms site. As far as H adsorbed on different surfaces of VH phase is concerned, physical adsorption is carried out more easily than chemical adsorption, and the behavior of H atoms adsorbed on the surface near VH phase region can be found more easily than that near MgH2 phase region.

关键词： plane-wave pseudopotential theory magnesium hydride diffusion adsorption

Studies on the Relation between the Composition of Thermal Sensitive MnZn Ferrite and Curie Temperature

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Journal of Materials science & Technology 2000年第2期16卷 209-210页

作者： Mengkui WANG (Department of Physics, Jinzhou Teachers college, Jinzhou 121003. china) Junyue WANG (Jinzhou Audio-Visual Education Center, Jinzhou 121000, china) Ke SUN (Department of Physics,{3., Shenyang 110006, china) Department of Physics Jinzhou Teachers College Jinzhou 121003 China Jinzhou Audio-Visual Education Center Jinzhou 121000 China Department of Physics Northeastern University Shenyang 110006 China

Thermal sensitive MnZn ferrite is a kind of soft magnetic ferrite material with lower Curie temperature (Tc) and can be used to make many kinds of magnetic thermal sensitive sensors with high sensitivity. In this paper, the relation between the composition of thermal sensitive ferrite and TC was studied. It was found that TC changes linearly with ZnO extent when the content of Fe2O3.is fixed. Based on lots of experiments, an experimential formula to determine was given out.

关键词： Studies on the Relation between the Composition of Thermal Sensitive MnZn Ferrite and Curie Temperature ZnO

Surface Nanocrystallization of Magnesium Alloy AZ91D by High-Energy Shot Peening

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Journal of Wuhan university of Technology(Materials science) 2009年第4期24卷 515-519页

作者：张津 School of Materials science & Engineering University of Science and Technology Beijing college of Materials science & Engineering Chongqing University of Technology

High-energy shot peening （HESP）, a method to produce severe plastic deformation by high velocity flying balls, was applied on die cast magnesium alloy AZ91D. Effects of surface nanocrystallization by HESP and heat treatment at different temperatures were investigated. The mi- crostructure evolution was conducted using X-ray diffraction （XRD） and field emission scanning electronic microscopy （FESEM）. The hardness was measured by microhardness tester. The experimental results show that surface nanocrystrallization of AZ91D obtained by HESP would lead to the increase of microhardness. Low temperature heated at 100℃ for 1 h do not change the property obviously. However, both the microstructure and microhardness vary greatly after heat treatment at 400℃ for 1 h.

关键词： AZ91 D surface nanocrystallization HESP microhardnss corrosion resistance

Ultrahigh pressure (>7 GPa) gneissic K-feldspar (-bearing) garnet clinopyroxenite in the Altyn Tagh, NW china: Evi- dence from clinopyroxene exsolution in garnet

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science china Earth sciences 2005年第7期48卷 1000-1010页

作者： LIU Liang1,3. CHEN Danling1, ZHANG Anda1, SUN Yong1, WANG Yan1, YANG Jiaxi1,2 & LUO Jinhai1 1. Key Laboratory of Continental Dynamics of the Ministry of Education of china, Northwest university, Xi’an 710069, china 2. {3. of Earth science and Land Resources, Chang’an university, Xi’an 710054, china 3. The Laboratory of Orogen and Basin of the Ministry of Education, Peking university, Beijing 100871, china Key Laboratory of Continental Dynamics Ministry of Education of China Northwest University Xi'an 710069 China Laboratory of Orogen and Basin Ministry of Education Peking University Beijing 100871 China college of Earth science and Land Resources Chang'an University Xi'an 710054 China

The exsolution of clinopyroxene and rutile in coarse-grain garnet is found in the gneissic K-feldspar(-bearing) garnet clinopyroxenite from Yinggelisayi in the Altyn Tagh, NW china. The maximum content of the exsolved clinopyroxene in the garnet is up to >5% by volume. The reconstructed precursor garnet (Grt1) before exsolution has a maximum Si content of 3.061 per formula uint, being of supersilicic or majoritic garnet. The peak-stage metamorphic pressure of >7 GPa is estimated using the geobarometer for volume percentage of exsolved pyroxene in garnet and the Si-(Al+Cr) geobarometer for majoritic garnet, and the temperature of about 1000℃ using the ternary alkali-feldspar geothermometer and the experimental data of ilmen- ite-magnetite solid solution. The protoliths of the rocks are intra-plate basic and intermediate ig- neous rocks, of which the geochemical features indicate that they are probably the products of the evolution of basic magma deriving from the continental lithosphere mantle. The rocks are in outcrops associated with ultrahigh pressure garnet-bearing lherzolite and ultrahigh pressure garnet granitoid gneiss. All of these data suggest that the ultrahigh pressure metamorphic rocks in the Altyn Tagh are the products of deep-subduction of the continental crust, and such deep- subduction probably reaches to >200 km in depth. This may provide new evidence for further discussion of the dynamic mechanism of the formation and evolvement of the Altyn Tagh and the other collision orogenic belts in western china.

关键词： Altyn Tagh gneissic K-feldspar (-bearing) garnet clinopyroxenite clinopyroxene exsolution in garnet ultra-high pressure metamorphism.

Randomization of classical inference patterns and its application

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science in china(Series F) 2007年第6期50卷 867-877页

作者： WANG GuoJun1,2 & HUI XiaoJing1,3. Institute of Mathematics, Shaanxi Normal university, Xi’an 710062, china 2 Research Center for science, Xi’an Jiaotong university, Xi’an 710049, china 3.college of Mathematics and Computer science, Yan’an university, 716000, china 1. Institute of Mathematics Shaanxi Normal University Xi’an 710062 China 2. Research Center for science Xi’an Jiaotong University Xi’an 710049 China 3. college of Mathematics and Computer science Yan’an University 716000 China

By means of randomization, the concept of D-randomized truth degree of formulas in two-valued propositional logic is introduced, and it is proved that the set of values of D-randomized truth degree of formulas has no isolated point in [0,1]. The concepts of D-logic pseudo-metric and D-logic metric space are also introduced and it is proved that there is no isolated point in the space. The new built D-randomized concepts are extensions of the corresponding concepts in quantified logic. Moreover, it is proved that the basic logic connectives are continuous operators in D-logic metric space. Lastly, three different types of approximate reasoning patterns are proposed.

关键词： D-randomized mapping D-randomized truth degree D-similarity D-logic metric space approximate reasoning

A New Clustering Algorithm for Categorical Attributes

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International Journal of Minerals,Metallurgy and Materials 2000年第4期14卷 318-322页

作者： Songfeng Lu, Zhengding Lu (college of Computer science and Technology, Huazhong university of science and Technology, Wuhan 43.074, china) college of Computer science and Technology Huazhong University of Science and Technology Wuhan 430074 China

In traditional data clustering, similarity of a cluster of objects is measured by distance between objects. Such measures are not appropriate for categorical data. A new clustering criterion to determine the similarity between points with categorical attributes is pre- sented. Furthermore, a new clustering algorithm for categorical attributes is addressed. A single scan of the dataset yields a good clus- tering, and more additional passes can be used to improve the quality further.

关键词： data mining clustering similarity Information

Use of the modified viral satellite DNA vector to silence mineral nutrition-related genes in plants: silencing of the tomato ferric chelate reductase gene, FRO1, as an example

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science china(Life sciences) 2008年第5期51卷 402-409页

作者： HE XiuXia1,2,JIN ChongWei1, LI GuiXin3. YOU GuangYi4, ZHOU XuePing3.& ZHENG ShaoJian4 1 Key Laboratory for Environmental and Ecosystem Health of the Ministry of Education, college of Environmental and Resource science, Zhejiang university, Hangzhou 3.0029,{3. 2 college of Life science, Changchun university of science and Technology, Changchun 13.022,{3. 3.Institute of Biotechnology, Zhejiang university, Hangzhou 3.0029,{3. 4 State Key Laboratory of Plant Physiology and Biochemistry, college of Life science, Zhejiang university, Hangzhou 3.0058,{3. 1. Key Laboratory for Environmental and Ecosystem Health of the Ministry of Education College of Environmental and Resource Science Zhejiang University Hangzhou 310029 China 2. college of Life science Changchun University of Science and Technology Changchun 130022 China 3. Institute of Biotechnology Zhejiang University Hangzhou 310029 China 4. State Key Laboratory of Plant Physiology and Biochemistry College of Life Science Zhejiang University Hangzhou 310058 China

Virus-induced gene silencing (VIGS) is potentially an attractive reverse-genetics tool for studies of plant gene function, but whether it is effective in silencing mineral nutritional-related genes in roots has not been demonstrated. Here we report on an efficient VIGS system that functions in tomato roots using a modified viral satellite DNA (DNAmβ) associated with Tomato yellow leaf curl china virus (TYLCCNV). A cDNA fragment of the ferric chelate reductase gene (FRO1) from tomato was inserted into the DNAmβ vector. Tomato roots agro-inoculated with DNAmβ carrying both a fragment of FRO1 and TYLCCNV used as a helper virus exhibited a significant reduction at the FRO1 mRNA level. As a consequence, ferric chelate reductase activity, as determined by visualization of the pink FeBPDS3.complex was significantly decreased. Our results clearly demonstrated that VIGS system can be employed to investigate gene function associated with plant nutrient uptake in roots.

关键词： virus-induced gene silencing roots ferric chelate reductase

Thermal stability conditions of a weakly interacting Fermi gas in a weak magnetic field

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Progress in Natural science:Materials International 2009年第1期19卷 121-124页

作者： Fudian Mena,Hui Liub,Houyu Zhua a college of Physics science and Technology,china {3. of Petroleum(East china),Dongying 257061,china b college of science,Anhui science and Technology {3.,Fengyang 23.100,china [a]college of Physics science and Technology China University of Petroleum (East China) Dongying 257061 China [b]College of Science Anhui Science and Technology University Fengyang 233100 China

On the basis of the results derived from pseudopotential method and ensemble theory,thermal stability of a weakly interacting Fermi gas in a weak magnetic field is studied by using analytical method of *** exact analytical expressions of stability conditions at different temperatures are given,and the effects of interactions as well as magnetic field on the stability of the system are *** is shown that there is an upperlimit magnetic field for the stability of the system at low temperatures,and there is an attractive dividing value at high *** attractive interaction is lower than the critical value,the stability of the system has no request for magnetic field,but if attractive interaction is higher than the dividing value,a lower-limit magnetic field exists for the stability of the system.

关键词： Fermi gas Interaction Heat capacity Stability

A VARIATIONAL MODEL FOR 2-D MICROPOLAR BLOOD FLOW

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Journal of Hydrodynamics 2003年第3期15卷 119-121页

作者： He Ji-huan college of science, Shanghai Donghua university, Shanghai 200051,{3., college of science Shanghai Donghua University Shanghai 200051 China

The micropolar fluid model is an essential generalization of thewell-established Navier-Stokes model in the sense that it takes into account the microstructure ofthe fluid. This paper is devolted to establishing a var... 详细信息

关键词： micropolar flow blood flow variational principle semi-inverse method