用体式显微镜研究SiC单晶中的微管缺陷

用拉曼光谱、X射线双晶衍射仪以及体式显微镜,对升华法生长的6H-SiC单晶品质、SiC单晶中的微管缺陷进行表征.通过对SiC单晶腐蚀前后的微管数目比较发现,微管尺寸和其所形成的腐蚀坑大小并不是呈线性关系,腐蚀前后用体式显微镜观察到的微管数目大致相等.从实验数据发现,微管的尺寸有最小值,这给SiC微管密度分布,提供了一种无损检测方法.     

故障安全逻辑系统的研究进程及向自校验逻辑系统的演变

本文简要地介绍了近十余年来关于故障安全逻辑系统和自校验逻辑系统的发展情况,并指出这两者之间的区别和联系.文后列举了有关论文目录近一百条,这些文献包括了这一时期内各阶段的主要研究成果.     

多元多相体系化学平衡组成的计算

本文从用计算机代替人工计算多元多相复杂体系化学平衡问题出发,对应用于计算机的Brinkley法,Vcs法及White法作了讨论和比较。指出White法在计算机上实现解决计算多元多相体系化学平衡问题的优点。并介绍了用White法编制的计算多元多相体系化学反应平衡的计算机应用程序的结构及基本工作原理。列出考题。其计算结果与位于联邦德国阿亨大学的冶金热力学数据库、中国科学院化工冶金研究所的无机热化学数据库的计算结果相一致。     

2030板带冷连轧机的振动分析

针对2030mm板带冷连轧机发生的振动问题,通过现场综合测试,了解轧机振动的特征与影响振动的主要因素,在分析研究与模拟实验的基础上,找到了振动的原因.     

A new insight into rapid oxidation of alloy 925 contaminated by oxide powder

Rapid oxidation takes place both in the labora-tory and in industrial conditions when alloy 925 is con-taminated by oxide powder,and the oxidation rate is much ...     

巨框格栅式双钢板剪力墙体系抗震性能

为满足km级超高层在高地震设防烈度下的抗震性能要求,提出一种以格栅式双钢板–混凝土组合剪力墙为主要抗侧力构件的km级巨框格栅式双钢板剪力墙体系,围绕该体系的弹塑性抗震性能展开了研究,建立km级巨框格栅式双钢板剪力墙体系弹塑性动力时程分析模型,使用SAUSAGE计算该模型在罕遇地震作用下的地震响应,分析结构变形分布、结构...     

最优预见算法构造电火花放电间隙控制专家系统研究

介绍最优预见控制算法 ,并给出其具体实现过程。阐述最优预见控制算法在构造电火花放电间隙控制专家系统中的应用技术实例。     

Exploratory study of betavoltaic battery using ZnO as the energy converting material

Third-generation-semiconductor zinc oxide is utilized as an energy converting material in a betavoltaic battery, where 0.06 Ci~(63) Ni and 8 Ci~(147) Pm are used as the beta sources. Based on a Monte Carlo simulation, the full scales of the devices are derived as 17 and 118 lm,respectively, for both sources. The influences of semiconductor doping concentrations on the electrical properties of the devices are analyzed. For a typical doping concentration N_A= 10~(17) cm~(-3), N_D= 10~(16) cm~(-3), the conversion efficiencies are 7.177% and 1.658%, respectively, using63 Ni and147 Pm sources. The calculation results of energy deposition in materials for the two sources show that the doping concentrations drop to 1 × 10~(13)–5×10~(14) cm~(-3) and 1 × 10~(12)–5×10~(13), and accordingly, the energy conversion efficiencies rise to 14.212% and 18.359%, respectively.     

Microstructure Evolution of Ni-Co Alloys During Crystallization and Amorphization Process

Journal of Superconductivity and Novel Magnetism - A molecular dynamics simulation has been conducted in Ni73Co27 and Ni74Co26 alloys during rapid solidification at the cooling rate of...     

Shielding effectiveness of boron-containing ores in Liaoning province of China against gamma rays and thermal neutrons

In this study, the mass attenuation coefficient of boron-containing ores in the Liaoning province of China was calculated using Win XCOM software to investigate the shielding effectiveness of these ores against gamma rays. The mass attenuation coefficients were also calculated using MCNP-4 B code and compared with Win XCOM results; consequently, a good consistency between the results of Win XCOM and MCNP-4 B was observed. Furthermore, the G-P fitting method was used to evaluate the values of exposure buildup factor(EBF) in the energy range of 0.015–15 Me V up to 40 mean free paths. Among the selected ores, boron-bearing iron concentrate ore(M3)was determined to be the best gamma ray shielding ore owing to its higher values of mass attenuation coefficient and equivalent atomic number and lower value of EBF.Moreover, American Evaluated Nuclear Data File(ENDF/B-VII) was used to analyze the shielding effectivenessagainst thermal neutrons. It was determined that Szaibelyite(M2) is the best thermal neutron shielding material.This study would be useful for demonstrating the potential of boron-containing ores for applications in the field of nuclear engineering and technology.