材料期刊网

S. Kubono , 何建军 , H. Yamaguchi , D. M. Kahl , S. Hayakawa , T. Teranishi , S. Cheribini , M. Gulino , Y. K. Kwon , T. Hashimoto , Y. Wakabayashi , N. Iwasa , S. Kato , T. Komatsubara , D. N. Binh , L. H. Khiem , N. N. Duy , T. Kawabata , C. Spitaleri , G. G. Rapisarda , M. La Cognata , L. Lamia , R. G. Pizzone , S. Romano , A. Coc , N. de Sereville , F. Hammache , G. Kiss , S. Bishop

原子核物理评论 doi:10.11804/NuclPhysRev.33.02.212

关键词:

关键天体反应18Ne（α，p）21Na的实验研究

张立勇 , 许世伟 , 何建军 , H. Yamaguchi , S. Kubono , Y. Wakabayashi , 陈思泽 , 胡钧 , 马朋 , Y. Togano , T. Hashimoto , D. Kahl , T. Teranishi , 陈若富 , 王宏伟 , 田文栋 , 郭冰 , S. Hayakawa , N. Iwasa , T. Yamada , T. Komatsubara

原子核物理评论 doi:10.11804/NuclPhysRev.30.04.385

在X射线暴高温高密度的环境中，18Ne(α, p)21Na很可能是由热CNO循环突破到rp过程的一个重要反应。到目前为止，人们测得的反应率还存在很大的不确定性。实验中用CRIB(CNS Radioactive Ion Beam separator)提供的21Na放射性束轰击8.8 mg/cm2的聚乙烯厚靶，利用放置在θlab=-14°，0°，14°处的3套硅条探测器望远镜阵列对反冲轻粒子进行鉴别和测量，测得在一段能区(Ex=5.5～9.2 MeV)内21 Na(p, p)21 Na的激发函数。通过对21 Na(p, p)共振弹性散射截面进行R矩阵拟合，得到了22 Mg共振能级的自旋宇称以及质子宽度等信息，从而为计算18Ne(α, p)21Na反应率提供了实验参数。

关键词: 核天体物理 , X射线暴 , 放射性束 , 厚靶方法 , 共振散射

Dendritic coarsening of gamma ' phase in a directionally solidified superalloy during 24,000h of exposure at 1173 K

Materials Characterization

Dendritic coarsening of gamma' was investigated in a directionally solidified Ni-base superalloy during exposure at 1173 K for 24,000 h. Chemical homogeneity along different directions and residual internal strain in the experimental superalloy were measured by electronic probe microanalysis (EPMA) and electron back-scattered diffraction (EBSD) technique. It was indicated that the gradient of element distribution was anisotropic and the inner strain between dendrite core and interdendritic regions was different even after 24,000 h of exposure at 1173 K, which influenced the kinetics for the dendrite coarsening of gamma' phase. (C) 2010 Elsevier Inc. All rights reserved

关键词: Superalloy;Coarsening;Exposure;Segregation;ni-base superalloy;evolution;field

Corrosion of Y, Fe and Fe-15Y in H_2-H_2S Mixture under 10~(-3) Pa S_2 at 600～800℃

Yan NIU , Weitao WU and Chaoliu ZENG (State Key Lab. for Corrosion and Protection , Institute of Corrosion and Protection of Metals , Chinese Academy of Sciences , Shenyang 110015 , China)F. Gesmundo and F. Viani (Instituto di Chimica , Facolta di Ingegneria , Un

材料科学技术（英文）

The corrosion of an Fe-based alloy containing 15 wt pct Y in H2-H2S mixtures under 10-3 Pa S2 was studied at 600~800℃ in an attempt to find materials with improved sulphidation resistance with respect to pure Fe. The presence of Y has been shown to be beneflcial, but not sufficient to the level expected. In fact, the alloy is able to form at all tested temperatures an external FeS layer, beneath which a zone containing a mixture of the two sulphides is also present. Thus,Fe can still diffuse through this region to form the outer FeS layer with non-negligible rate. The corrosion rate of Fe is considerably reduced by the Y addition. but the alloy corrodes still much more rapidly than Y. The sulphidation kinetics is generally rather irregular for both the pure metals, while the corrosion rate of the alloy decreases with time and tends to become parabolic after an initial period of 12~17 h. The sulphidation behaviour of the alloys is discussed by taking into account the presence of an intermetallic compound Fe17Y2 and the limited solubility of Y in Fe

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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

Corrosion of Y, Fe and Fe-15Y in H-2-H2S mixture under 10(-3) Pa S-2 at 600 similar to 800 degrees C

材料科学技术（英文）

The corrosion of an Fe-based alloy containing 15 wt pet Y in H-2-H2S mixtures under 10(-3) Pa S-2 was studied at 600 similar to 800 degrees C in an attempt to find materials with improved sulphidation resistance with respect to pure Fe. The presence of Y has been shown to be beneficial, but not sufficient to the level expected. In fact, the alloy is able to form at all tested temperatures an external FeS layer, beneath which a zone containing a mixture of the two sulphides is also present. Thus, Fe can still diffuse through this region to form the outer FeS layer with non-negligible rate. The corrosion rate of Fe is considerably reduced by the Y addition, but the alloy corrodes still much more rapidly than Y. The sulphidation kinetics is generally rather irregular for both the pure metals, while the corrosion rate of the alloy decreases with time and tends to become parabolic after an initial period of 12 similar to 17 h. The sulphidation behaviour of the alloys is discussed by taking into account the presence of an intermetallic compound Fe17Y2 and the limited solubility of Y in Fe.

关键词: high-temperature sulfidation;most-reactive component;ni-nb alloys;h2-h2s mixtures;behavior;600-degrees-c-800-degrees-c;oxidation

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

亚稳态He(23S)原子与N2H4分子传能产物的发光研究

胡义华 , 刘美希 , 陈丽 , 王小涓 , 储焰南 , 曹德兆

量子电子学报 doi:10.3969/j.issn.1007-5461.2001.04.008

本文在流动余辉装置上,研究了亚稳态He(23S)原子与N2H4分子碰撞传能,观察到了激发态产物NH(A3II→X3∑+)、NH(c1II→a1△)、NH2(A2A1→X2B1)的发射光谱,由相对光谱强度求得了形成各产物的通道比;分析NH(A3II,v＇=0)的转动分辨谱的结果表明,v＇=0能级上的转动布居是"双模”分布,激发态产物NH(A)、NH2(A)的形成机理可能是: He(23S)+N2H4→N2H4*→NH(A)+NH2(A)+H.

关键词: 碰撞传能 , 化学发光 , NH(A3Ⅱ)的发射光谱