材料期刊网

晕核6He(25 MeV/u)的单、双中子转移截面测量

叶沿林 , 庞丹阳 , 葛愉成 , 江栋兴 , 郑涛 , 王全进 , 李智焕 , 李湘庆 , 艾颖 , 张高龙 , 王佳 , 陈志强 , 胡青元 , A.Ozawa , Y.Yamaguchi , C.Wu , R.Kanungo , D.Fang , I.Tanihata

原子核物理评论 doi:10.3969/j.issn.1007-4627.2005.01.001

实验测量了25 MeV/u 的6He+9Be反应中的单、双中子转移微分截面.利用反应耦合道模型初步分析了实验数据, 计算大体重现截面值.转移反应对末态有相当的选择性, 并且双中子转移截面主要来自到基态的一步过程.后角度截面的上升可能与连续态的耦合有关.

关键词: 晕核 , 转移反应 , 反应耦合道模型

晕核6He(25 MeV/u)在9Be上的弹性散射研究

庞丹阳 , 叶沿林 , 江栋兴 , 郑涛 , 王全进 , 李智焕 , 李湘庆 , 陈志强 , 胡青元 , 张高龙 , 王佳 , A.Ozawa , Y.Yamaguchi , C.Wu , R.Kanungo , D.Fang , I.Tanihata

原子核物理评论 doi:10.3969/j.issn.1007-4627.2005.01.003

分析了北京大学核物理实验小组在日本RIKEN实验室完成的25 MeV/u 6He和9Be的弹性散射实验数据, 得到了弹性散射微分截面角分布.利用双折叠模型, 并通过拟合弹性散射微分截面得到了此弹靶体系在此能量下的弹性散射光学势.

关键词: 中子晕核 , 弹性散射 , 双折叠模型 , 光学模型 , 微分截面角分布

晕核6He(25 MeV/u)在9Be上的破裂反应

王佳 , 叶沿林 , 江栋兴 , 郑涛 , 王全进 , 李智焕 , 李湘庆 , 张高龙 , 庞丹阳 , 吴翠娥 , 陈志强 , 胡青元 , A.Ozawa , Y.Yamaguchi , R.Kanungo , D.Fang , I.Tanihata

原子核物理评论 doi:10.3969/j.issn.1007-4627.2005.01.002

25 MeV/u 6He+9Be反应的实验中利用多个探测器望远镜对反应产物进行了测量, 对实验中各个角度测量到的4He进行观察, 将其中两个有高能峰成分的探测器划分成三部分, 得到不同角度4He的单举能谱和破裂产生4He的微分截面.

关键词: 中子晕核 , 破碎反应 , 微分截面 , 6He

Energy levels of the d*(8) electron and d*(2) hole system

Physical Review B

In the investigation of the optical and magnetic properties of the semiconductors containing transition-metal ions, the one-electron orbital cannot be treated with a pure d orbital because of a strong covalence. This paper presents the energy matrix of the d*(8) and d*(2) (d* means a modified d function) system, in which the covalence is described by two covalent factors. The differences between the matrix diagonal elements of the t(2)(m)e(n) term of the d*(8) system and the t(2)(6-m)e(4-n) term of the d*(2) system vary with m and n. The d(N) electron system can be explained with the d(10-N) hole system because the difference between the energy matrix of the d(N) and d(10-N) systems has a fixed value. However, this kind of simple relation does not exist for the d*(N) and d*(10-N) systems when the covalence is considered. A numerical calculation shows that the variation of the energy levels with the covalence for Ni2+ in the d*(8) electron system is larger than that in the d*(2) hole system. The calculated energy levels obtained from the d*(8) matrix are in good agreement with the experimental data of the Ni2+ ion for ZnS:Ni and ZnSe:Ni. This suggests that the d*(8) electron system instead of the d*(2) hole system should be used in the investigation of optical and magnetic properties of semiconductor containing Ni2+ ions.

关键词: zns-ni;absorption;vanadium;impurities;spectra;ions

液晶材料与3D显示

张兴 , 郑成武 , 李宁 , 周兴丹 , 李正强 , 华瑞茂

液晶与显示 doi:10.3788/YJYXS20122704.0448

介绍了3D显示的基本原理,重点介绍了目前3D显示的主流技术类型,包含了眼镜式3D技术以及裸眼式3D技术,其中眼镜式3D技术包含色差式3D技术、偏光式3D技术和主动快门式3D技术;裸眼式3D技术包含视差屏障式3D技术、柱状透镜式3D技术、指向光源式3D技术和多层显示式3D技术.阐述了各种3D显示技术的基本实现原理和应用领域、并对涉及液晶显示的几种3D技术的优缺点进行了对比.结合液晶材料的特点与3D液晶显示的实际要求,阐述了3D液晶面板对液晶材料快速响应方面的要求,以及液晶透镜对液晶材料光学各向异性参数的要求.

关键词: 3D显示 , 眼镜式3D显示 , 裸眼式3D显示 , 液晶材料

COMPARISON OF FATIGUE AND CREEP BEHAVIOR BETWEEN 2D AND 3D-C／SiC COMPOSITES

D.Han , S.R.Qiao , M.Li , J.T.Hou , X.J.Wu

金属学报(英文版)

The differences of tension-tension fatigue and tensile creep characters of 2D-C/SiC and 3D-C/SiC composites have been scrutinized to meet the engineering needs. Experiments of tension-tension fatigue and tensile creep are carried out under vacuum high temperature condition. All of the high temperature fatigue curves are flat; the fatigue curves of the 2D-C/SiC are flatter and even parallel to the horizontal axis. While the tension-tension fatigue limit of the 3D-C/SiC is higher than that of the 2D-C/SiC, the fiber pullout length of the fatigue fracture surface of the 3D-C/SiC is longer than that of the 2D-C/SiC, and fracture morphology of the 3D-C/SiC is rougher, and pullout length of the fiber tows is longer. At the same time the 3D-C/SiC has higher tensile creep resistance. The tensile curve and the tensile creep curve of both materials consist of a series of flat step. These phenomena can be explained by the non-continuity of the damage.

关键词: 2D-C/SiC , null , null

Surface properties of 3d transition metals

Philosophical Magazine

Using the projector augmented wave method within density functional theory, we present a systematic study of the layer relaxation, surface energy and surface stress of 3d transition metals. Comparing the calculated trends for the surface energy and stress with those obtained for 4d and 5d metals we find that magnetism has a significant effect on the surface properties. Enhanced surface magnetic moments decrease the size of the surface relaxation, lower the surface energy and surface stress, leading to compressive stress in Cr and Mn.

关键词: surface relaxation;surface energy;surface stress;magnetic transition;metals;density functional theory;full charge-density;initio molecular-dynamics;total-energy;calculations;augmented-wave method;ab-initio;electronic-structure;atomic volume;work function;basis-set;relaxation

R&D STATUS ON INTERMETALLICS IN CHINA

CHEN Guoliang(State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing Beijing 100083 , China)SHI Changxu (Academia Sinica , Beijing 100864 , China)

金属学报(英文版)

This paper briefiy introduces the R&D of intermetallics in China. R&D on intermetallics in a national scale in China began near ten years ago. The investigation in past years focused on the fundamental research and materials development. A significant progress has been made. Various components that made of Ti3Al Ni3Al, TiAl and Fe3Al have been successfully manufactured Some of them have been evaluted. It is expected that some intermetallic alloys will be produced in an industrial scale in the near future.

关键词: :intermetallic alloys , null , null , null

R & D ACTIVITIES ON AEROSPACE MATERIALS IN KOREA

H.M. Kim(Korea Institute of Machinery and Materials , Korea Manuscript received 26 August 1996)

金属学报(英文版)

This paper briefly reviews research and development programs in Korean aerospace industry,with an emphasis on aircraft materials technology. International collaborations in these areas are outlined and the R & D activities are highlighted against the　background of the national economy.It is shown that the investment from government agencies and large enterprises has led to healthy development of aerospace materials industries in Korea.

关键词: :R & D , null , null , null

陶瓷3D打印技术综述

杨孟孟 , 罗旭东 , 谢志鹏

人工晶体学报

本文介绍了陶瓷3D打印技术目前的发展状况、主要的成型技术和重要的应用领域，重点介绍3D打印技术在陶瓷方向的应用。回顾了可适用于直接三维打印和立体光固化法打印的氧化物( Al2 O3、ZrO2)和非氧化物( Si3 N4、SiC)陶瓷浆料的最新研究成果及成型技术对制品性能的影响，并展望了陶瓷3D打印技术未来的发展方向。

关键词: 3D打印 , 陶瓷 , 浆料 , 成型技术