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Electrochemical properties and structure of MlNi_(5-x)Sn_x system

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Journal of university of science and technology beijing 2002年第4期9卷 269-272页

作者： Qin Lin, Dajian zhu, and Shuang ZhaoMetallurgy school,{2., beijing 100083, china Metall. Sch. Univ. of Sci. and Technol. Beijing Beijing 100083 China

The electrochemical properties and structure of MlNi_(5-x)Sn_x (x= 0-0.5)hydrogen storage alloys were investigated by pressure-composition isotherms, electrochemicalmeasurements, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and atomic *** a small amount of tin substitution, the cycle life increases by 52.percent (0.5C) and 42.ercent (1.0C), but maximum discharge capacity decreases only by 3.0 percent and 3.5 percent,respectively. The cycle life is obviously improved by the low volume expansion and the formed SnO_2.urface layers upon electrochemical cycling. The substitution of Ni by Sn leads to an increase ofthe unit cell volume and charge-discharge cycle life and decrease of the plateau pressure,hysteresis and the hydrogen storage capacity. The standard enthalpy of hydride formation decreaseswith increasing tin substitution. The main factor that influences the standard enthalpy of thehydriding reaction is the number of the outer orbit electrons and not the atomic size factor.

关键词： hydrogen storage alloy MlNi_(5-x)Sn_x electrochemical properties structure

Experimental Study of Fluid Flow in Thin Slab Continuous Caster Mould with Water-Model

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International Journal of Minerals,Metallurgy and Materials 1999年第1期13卷 15-19页

作者： Yanping Bao Jianqiang zhu Naiyuan Tian Baomei Xu(Metallurgy school,{2., beijing 100083, china) Metallurgy school University of Science and Technology Beijing Beijing 100083 China

Model study is an efficient method for optimizing the siructure of the mould and the submerged entry nozzle (SEN). Based on the similarity criteria, a full-scale water model has been established in accordance with the mould of thin-slab caster of the CSP (Compact Strip Production) operation. The effects of SEN structure including outlet area, outflow angle, nozzle width, thick-ness and immersion depth have been studied under high speed casting by measuring the amplitude and the impetus of top waves. By the orthogonal experiment design, not only the influence of the faCtors was estimated, but also the optimum work condition was judged. The rules of the fluid flow phenomena were summarized. The principle for choosing a reasonable structure of SEN was discussed.

关键词： thin-slab casting mould submerged entry nozzle (SEN) water-model

Strain in solidifying shell of continuous casting slabs

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Journal of university of science and technology beijing 2003年第6期10卷 26-29页

作者： Guosen zhu, Xinhua Wang, Huixiang Yu, and Wanjun WangMetallurgical Engineering school,{2., beijing 100083, china Metall. Eng. Sch. Univ. of Sci. and Technol. Beijing Beijing 100083 China

Two-dimension unsteady heat transfer model was applied to obtain the surfacetemperature and the shell thickness of continuous casting slabs during the process ofsolidification. On the basis of which, the mathematical model of strain at the interface of solidand liquid steel was set up. Through which, the strain in the solidifying shell under normal andabnormal operation conditions was gained. The results indicate that the strain is small under thenormal operation conditions and the internal crack never happens. However, when the variation of theroll gap is above 2.mm, the strain caused by which is greater than that caused by ***, the total strain exceeds the critical one and the internal crack is the result. So itis of great importance to maintain the fine state of continuous casting machine to avoid theappearance of internal crack.

关键词： internal crack strain bulging unbending continuous casting slab

Sticking-up Behaviors and Surface Friction of IF Electrogalvanized Sheet Steel in Forming

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International Journal of Minerals,Metallurgy and Materials 1999年第1期13卷 61-63,68页

作者： Jiming Hu Jixun Wu Yanping Lu Yanrong zhu (Material {2. and Engineering school, university of science and technology beijing, beijing 100083, china) Univ of science and technology Beijing Beijing China

X-ray diffraction (XRD), ball-disc friction and wearing machine and draw-bead test were introduced to investigat the strcusture and workability of IF sheet steel electrogalvanized deposits prepared from sulphate solution system. It was shown that the picking-up of the zinc coating on die strengthened with the increasing of friction factor which was originally affected by the coating's structure. Duing forming, (00X) planes (X= 2. 4) preferential orientation of zinc deposits increased, which resulted in enhanc ing the coating's friction behaviors. Therefore, the forming mechanism of electrogalvedzed deposit was demonstrated that both friction and the stricking -up behaviors of the coating are intensified simultaneously and affect each other.

关键词： electrogalvanized deposit forming friction factor

Magnetic properties and structure of very thin permalloy films

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Journal of university of science and technology beijing 2004年第3期11卷 225-229页

作者： Guanghua Yu Haifeng Li Tao Yang Fengwu zhu Materials science and Engineering {2., university of science and technology beijing, beijing 100083, china Mat. Sci. and Eng. Sch. Univ. of Sci. and Technol. Beijing Beijing 100083 China

In order to study the magnetic properties and structure of very thinpermalloy films, Ni_(81)Fe_(19) films of 12.nm in thickness were prepared by different instrumentsat an ultrahigh base vacuum and a lower base vacuum. The anisotropic magnetoresistance coefficients(ΔR/R) of Ni_(81)Fe_(19) (12.nm) films reached 1.6 % and 0.6 %, and the coercivities were 12. and334 A/m, respectively. X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) were usedto study the structure and surface chemical state. The experimental results show that the filmsprepared at the ultrahigh base vacuum have a smoother surface, a bigger grain size and a denserstructure with fewer defects than those prepared at the lower base vacuum.

关键词： NiFe film anisotropic magnetoresistance (AMR) coercivity structure

Interface reactions in film materials

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Journal of university of science and technology beijing 2003年第5期10卷 1-8页

作者： Fengwu zhu, Zhonghai Thai, and Guanghua YuMaterials science and Engineering {2., university of science and technology beijing, beijing 100083, china Univ Sci & Technol beijing Mat Sci & Engn Sch Beijing 100083 Peoples R China

Interface reaction (IR) is a frequently observed phenomenon in the study ofadvanced thin film materials. It is very important to study the reaction conditions at which IRhappens and then to suppress or make use of it, the necessary conditions, including boththermodynamical and dynamical conditions of IR were discussed in detail. IRs in various systems,including oxide/silicon, oxide/metal, metal/metal, metal/semiconductor andsemiconductor/semiconductor, were reviewed. Methods to suppress and make use of IR were alsointroduced.

关键词： interface reaction spin-valve multilayers gate dielectric

Maximal operators of pseudo-differential operators with rough symbols

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Applied Mathematics(A Journal of Chinese Universities) 2024年第1期39卷 174-180页

作者： Ramla Benhamoud zhu Xiang-rong school of Mathematical sciences Zhejiang Normal UniversityJinhua 321004China

Consider a pseudo-differential operator T_(a)f(x)=∫_(R^(n))e^(ix,ζ)a(x,ζ)f(ζ)dζwhere the symbol a is in the rough Hormander class L^(∞)S_(ρ)^(m)with m∈R andρ∈[0,1].In this note,when 1≤p≤2.if n(ρ-1)/p and a∈L^(∞)S_(ρ)^(m),then for any f∈S(R^(n))and x∈R^(n),we prove that M(T_(a)f)(x)≤C(M(|f|^(p))(x))^(1/p) where M is the Hardy-Littlewood maximal *** theorem improves the known results and the bound on m is sharp,in the sense that n(ρ-1)/p can not be replaced by a larger constant.

关键词： pseudo-differential operator rough Hormander class H-L maximal operator

Effects of Temperature and [S] on the Kinetics of Nitrogen Removal from Liquid Steel

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Journal of Materials science & technology 2001年第2期17卷 233-236页

作者： Jie FU, Shixiang ZHOU, Ping WANG, Lin DI and Jian zhu Metallurgy school,{2., beijing 100083, china Sch. of Met. Univ. of Sci. and Technol. Beijing Beijing 100083 China

The kinetics of denitrogenation from liquid steel was studied by using an oxygen-nitrogen analysis system(LECO TC-436) under 1600 degreesC similar to 2.13 degreesC conditions. The results show that when [S]=0.005%, nitrogen removal was controlled by nitrogen transfer in liquid diffusion layer, when [S]=0.012. and 0.140%, it was controlled by both nitrogen transfer in liquid diffusion layer and the chemical reaction at the liquid-gas interface below 2.50 degreesC, and by nitrogen transfer in liquid diffusion layer under 2.50 degreesC similar to 2.13 degreesC conditions. The activation energy E-a was 57 kJ/mol for 0.0050%[S], 95 kJ/mol for 0.012.[S], 165 kJ/mol for 0.140%[S]. The resistance of sulphur on nitrogen removal decreased with the temperature rose, and disappeared at 2.30 degreesC. Based on the results obtained, it has been answered why the nitrogen in liquid steel can be decreased rapidly by carbon-oxygen reaction under very high oxygen and sulphur content conditions during the BOF, EAF, VOD and AOD steelmaking processes.

关键词： Effects of Temperature and on the Kinetics of Nitrogen Removal from Liquid Steel

The influence of thermal radiation on MHD station-point flow past a stretching sheet with heat generation

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Acta Mechanica Sinica 2011年第4期27卷 502-509页

作者： Jing zhu.Lian-Cun Zheng.Xin-Xin Zhang Department of Mathematics and Mechanics,university of {2. and technology beijing,100083 beijing,china Thermal Engineering Department,university of {2. and technology beijing,100083 beijing,china Zheng Department of Mathematics and Mechanics University of Science and Technology Beijing Beijing China Thermal Engineering Department University of Science and Technology Beijing Beijing China

This letter is concerned with the plane and axisymmetric stagnation-point flows and heat transfer of an electrically-conducting fluid past a stretching sheet in the presence of the thermal radiation and heat generation or absorption. The analytical solutions for the velocity distribution and dimensionless temperature profiles are obtained for the various values of the ratio of free stream velocity and stretching velocity, heat source parameter, Prandtl number, thermal radiation parameter, the suction and injection velocity parameter and magnetic parameter and dimensionality index in the series form with the help of homotopy analysis method （HAM）. Convergence of the series is explicitly dis- cussed. In addition, shear stress and heat flux at the surface are calculated.

关键词： Thermal radiation MHD Laminar boundarylayers - Homotopy analysis method