材料期刊网，材料期刊，材料类期刊，材料期刊投稿

The grain size of AZ91 alloy was investigated in terms of the effects of cooling rate, superheat and steel gauze. It was found that rapid cooling rate and low superheat favoured the achievement of fine grain structures. The gauze had a less profound effect on the grain size in AZ91 magnesium alloy than that in A356 aluminum alloy. The mechanisms by which these factors affect grain refinement of AZ91 have also been discussed.

关键词: Superheat , null , null , null

Two-step magnetization in a spin-chain system on the triangular lattice: Wang-Landau simulation

Physical Review B

The Wang-Landau algorithm is used to study the thermodynamic and magnetic properties of triangular spin-chain system based on two-dimensional Ising model in order to understand the magnetic-order dynamics in Ca(3)Co(2)O(6) compound. The calculated results demonstrate that the equilibrium state of the rigid spins produces the two-step magnetization curve at low temperature even when the random-exchange term is considered. This work indicates that the four-step magnetization behavior observed experimentally must be due to the nonequilibrium magnetization.

关键词: calcium compounds;exchange interactions (electron);Ising model;magnetisation;thermodynamics;one-dimensional ca3co2o6;density-of-states;compound ca3co2o6;phase-diagram;proteins;crystal

EFFECT OF OXYGEN CONTENTS ON OXYGEN POTENTIALS OF H_2O-H_2 AND H_2O-H_2-INERTS GAS MIXTURES

FANG Zheng CHEN Xinmin(H.M.Chen) Central South University of Technology , Changsha , China FANG Zheng , Associate Professor , Department of Chemistry , Central South University of Technology , Changsha , China

金属学报(英文版)

By taking the effect of oxygen contents into account,a new set of formulae which represents the oxygen potentials of H_2O-H_2 and H_2O-H_2-inerts gas mixtures has been derived.Classi- cal representation is only a particular case of it.Some of the variables affecting equilibrium atmosphere when trace oxygen is present and optimum preparation of the gas mixtures to min- imize errors have been discussed.The reliability of some of previous equilibrium experiments under the oxygen potentials controlled by H_2O-H_2 or H_2O-H_2-inerts gas mixtures has also been criticized.

关键词: gas equilibration method , null , null , null

Ferromagnetism and superparamagnetism of ZnCoO : H nanocrystals

Applied Physics Letters

ZnCoO:H nanocrystals are weak ferromagnetic at room temperature with a small coercivity and a small remanence, whereas ZnCoO nanocrystals are paramagnetic. The thermal irreversibility of zero-field cooling and field cooling magnetizations of ZnCoO:H nanocrystals corresponds to the existence of superparamagnetism due to the nanosize effect. X-ray photoelectron spectra show the incorporation of Co(2+) ions inside the ZnO lattice without changing the wurtzite structure. Our data suggest that hydrogen can induce ferromagnetism in ZnCoO and that ferromagnetic ZnCoO:H crystals with small particle size can show the superparamagnetism. (C) 2008 American Institute of Physics.

关键词: magnetic semiconductors;zno;hydrogen;cobalt

H+4, H+5和H+7团簇离子的测量和确认

杨百方 , 缪竞威 , 杨朝文 , 师勉恭

原子核物理评论 doi:10.3969/j.issn.1007-4627.2002.z1.038

报告了H+4, H+5, H+7等团簇离子的测量结果. 确认可以由H+3与一个或多个H和H2相互作用形成较大的H+4, H+5, H+7等团簇离子.

关键词: H+4团簇离子 , H+5团簇离子 , H+7团簇离子

H型钢裂纹成因分析

王硕明 , 丁志军 , 于恒 , 张彩军

钢铁钒钛

研究了某H型钢厂采用半敞开方式浇注的H型钢腹板裂纹产生的原因.在该厂选取了26块有代表性裂纹的试样进行了细致的研究,研究认为:H型钢腹板裂纹主要是由钢中夹杂物因素造成,通过对钢中T[O]的研究发现,中间包T[O]量平均为94×10-6,铸坯中T[O]平均为60.8×10-6,同时对比1流铸坯和2流铸坯的T[O]量变化可以发现,中间包流场分布不合理.对该厂现有的中间包进行FLUENT模拟后发现,中间包稳流器矮坝较低,不能完全消除短路流,尤其在浇注后期,矮坝损耗殆尽,基本不起作用,短路流严重,应加以优化.

关键词: H型钢 , 裂纹 , 夹杂物 , 数学模拟

国内热轧H型钢工艺特点

徐峰 , 何彩红 , 徐勇

钢铁研究

简述了国内H型钢的发展现状,通过列举国内典型H型钢生产线,介绍分析了轧制H型钢的1-3-1、1-3和连轧三种工艺布置,以及目前轧制H型钢的X-X和X-H两种方法.根据目前国内生产状况,提出了H型钢技术改进的几项措施.

关键词: H型钢 , 生产工艺 , 万能轧机

INVESTIGATION ON DEPOSITIONS AND HARDNESS CHARACTERISTICS OF a SiC:H FILMS

X.F.Rong and Z.Y.Qin College of Mechanical Engineering , Taiyuan University of Technology , Taiyuan 030024 , China

金属学报(英文版)

In this paper, a deposition feature of a SiC:H films deposited by a RF sputtering system and a effect on the hardness of the films with various deposition conditions are investigated, and the effects of the silicon on a C:H are studied. It follows from the results that the properties of hardness can be changed with the depositing conditions. An increase of silane in the gas phase allows to deposit a SiC:H having tetrahedral structure. The sets of deposition conditions by which the different types of a SiC:H films can be deposited are obtained.

关键词: a SiC:H film , null , null