Segregation of alloying atoms at a tilt symmetric grain boundary in tungsten and their strengthening and embrittling effects

We investigate the segregation behavior of alloying atoms （Sr, Th, In, Cd, Ag, Sc, Au, Zn, Cu, Mn, Cr, and Ti） near Z3 （ 111 ） [1]-0] tilt symmetric grain boundary （GB） in tungsten and their effects on the intergranular embrittlement by performing first-principles calculations. The calculated segregation energies suggest that Ag, Au, Cd, In, Sc, Sr, Th, and Ti prefer to occupy the site in the mirror plane of the GB, while Cu, Cr, Mn, and Zn intend to locate at the first layer nearby the GB core. The calculated strengthening energies predict Sr, Th, In, Cd, Ag, Sc, Au, Ti, and Zn act as embrittlers while Cu, Cr, and Mn act as cohesion enhancers. The correlation of the alloying atom＇s metal radius with strengthening energy is strong enough to predict the strengthening and embrittling behavior of alloying atoms; that is, the alloying atom with larger metal radius than W acts as an embrittler and the one with smaller metal radius acts as a cohesion enhancer.     

固体表面室温燐光法测定淫羊藿甙

１引言 淫羊蕾甙（ｉｃａｒｉｉｎ）为中草药淫羊蕾的主要有效成分,有增加冠脉血流量的作用。淫羊蕾甙的测定方法有薄层扫描法,高效液相色谱法等。固体表面室温光法是一种微量技术与痕量分析相结合的分析方法,而建羊蕾甙的室温光法的研究未见文献报道。本文以Ｄｄ（Ａｃ）２为重原子微扰剂,以聚酰胺膜作基质时,能诱导出淫羊藿甙的ＲＴＰ发射。其激发波长为３００ｎｍ（弱峰）和４００ｎｍ（强峰）,发射波长为５００ｎｍ。淫羊藿甙含量在１．３５～６７５ ｎｇ／斑范围内与ＲＴＰ强度呈良好的线性关系,检出限达０,０６ ｎｇ／斑。该…     

环氧氯丙烷作重原子微扰剂在环糊精诱导室温磷光法中的应用

本文报道一种新型的重原子微扰剂－环氧氯丙烷（ＥＣＨ）,在此重原子微扰下,建立了β－环糊精诱导室温磷光法（β－ＣＤ－ＲＴＰ）测定痕量溴代萘（ＢｒＮ）的方法,结果令人满意。同时还在该体系中测定了溴代萘的ＤＴＰ寿命、猝灭常数、三元包合物的包接常数。实验结果证明,α－ＢｒＮ／ＥＣＨ／β－ＣＤ三分子包接配合物比β－ＢｒＨ／ＥＣＨ／β－ＣＤ三分子包接络合物包接更加有效,而且稳定性更强。     

同步扫描－固体基质室温磷光法同时测定痕量对位三联苯和间位三联苯的研究

本文提出了一种新的测定间三联苯和对三联苯的同步扫描－ＳＳ－ＲＴＰ法。固体基质选用慢速定量滤纸，重原子盐为Ｔｌ２ＳＯ４。以激发单色器和发射单色器的波长差△λ＝１８０ｎｍ进行同步扫描，其同步特征峰间三联苯为４５０ｎｍ，对三联苯为４９０ｎｍ（均指发射波长）。间三联苯可直接由该特征峰的高度进行定量测定。对三联苯在４９０ｎｍ处的特征峰略受间三联苯同步拖尾的影响，其峰值信号需加校正。间三联苯和对三联苯的线性范围分别为０．４６～９２ｎｇ／斑点和０．４６～４６ｎｇ／斑点     

Universal Scaling Law for Atomic Diffusion and Viscosity in Liquid Metals

The recently proposed scaling law relating the diffusion coefficient and the excess entropy of liquid [Samanta A et al. 2004 Phys. Reu. Lett. 92 145901; Dzugutov M 1996 Nature 381 137], and a quasi-universal relationship between the transport coefficients and excess entropy of dense fluids [Rosenfeld Y 1977 Phys. Rev. A 15 2545],are tested for diverse liquid metals using molecular dynamics simulations. Interatomic potentials derived from the glue potential and second-moment approximation of tight-binding scheme are used to study liquid metals.Our simulation results give sound support to the above-mentioned universal scaling laws. Following Dzugutov,we have also reached a new universal scaling relationship between the viscosity coefficient and excess entropy.The simulation results suggest that the reduced transport coefficients can be expressed approximately in terms of the corresponding packing density.     

发光分析

本文是《分析试验室》定期评述中“发光分析”课题的第四篇评述文章，它评述在１９９５年１月～１９９６年１２月间我国发光分析的发展概况，内容包括：荧光，磷光，化学发光和生物发光分析等方面，引用文献３５４篇。     

Structural Characteristics of Liquid Sn

We investigate the structural properties of liquid Sn. With the help of the internal friction (tanФ) method, it is found that a peak appears in the tan Ф - T curve, suggesting that an anomalous discontinuous temperatureinduced structure change may take place in liquid Sn. From the experimental data of pair distribution functions, we calculate the viscosity η and the excess entropy S and it is found that there are a peak of viscosity in the η-T curve and a bend of excess entropy in the S - T curve, which give a positive support to the appearance of the internal-friction peak in the tan Ф- T curve.     

环糊精诱导二苯甲酮敏化α－溴代萘室温磷光分析法

环糊精诱导二苯甲酮敏化α－溴代萘室温磷光分析法谢剑炜，许金钩，陈国珍，刘长松（厦门大学化学系现代分析化学研究所，厦门，３６１００５）（山西大学化学系，太原）关键词二苯甲酮，敏化室温磷光，α－溴代萘，环糊精胶束、环糊精等有序介质能有效地使能量给体和受体...     

山西省化学会召开1979年分析化学论文报告会

山西省化学会1979年分析化学论文报告会于12月3—8日在山西太原举行。来自全省科研、生产、高等学校的97位代表出席了会议。会议收到论文76篇,组织了9篇专题学术报告,省化学会副理事长彭少逸同志作了题为“关于美国化学研究的—鳞片爪”的报告,引起了代表们的极大兴趣。会议期间宣读论文68篇,介绍了代表们近年来在化学分     

富勒烯C_(60)及其电荷转移配合物的吸光、发光特性研究

对Ｃ６０克量级合成与制备获得成功以来的近七、八年间有关溶液中Ｃ６０及其电荷转移配合物（ＣＴＣ）吸光、发光特性研究做了详尽综述。化学特性的改善展示了Ｃ６０及其ＣＴＣ作为新型材料的潜在应用前景。