侵彻环境下两种钨合金的细观响应特性

本文实验发现具有较大密度和较高速度的93W钨合金长杆模拟弹的穿靶深度反而比密度较小，速度较低的90W钨合金长杆弹的穿靶深度小．针对这一现象，本文从两种材料在侵彻环境下的细观响应特性的差异上给出了有实验根据的合理分析，结论是90W在侵彻环境下较易于形成绝热剪切带，从而在弹头部发生“自锐化”效应所致．     

STM/AFM studies of the evolution of morphology of electroplated Ni/W alloys

The surface morphology evolution of Ni/W alloys was studied, as a function of the alloy composition. Using the modified plating baths developed in our laboratory recently, electroplated Ni/W alloys with different W content, in the range of 7–67 atom percent (a/o), can be obtained. This was found to lead to different structures, ranging from polycrystalline fcc-Ni type structure to amorphous, followed by orthorhombic with increasing W content in the alloy. Powder XRD was studied to determine the crystal structures. Ex situ STM, AFM and SEM were used to study in detail the surface morphologies of the different alloys, and their evolution with increasing W content.

The important findings are that a mixture of two crystalline forms can give rise to an amorphous structure. Hillocks that are usually a characteristic of epitaxial growth can also exist in the amorphous alloys. Oriented scratches caused by stress can also be formed.

Up to 20 a/o of W is deposited in the alloys in crystalline form, with the fcc-Ni type structure. Between 20 and about 40 a/o an amorphous structure is observed, and above that an orthorhombic crystal structure is seen, which is characteristic of the NiW binary alloy. Careful choice of the composition of the plating bath allowed us to deposit an alloy containing 67 a/o W, which corresponds to the composition NiW₂.     

泛连通图定理和Ore2条件

记Ore2=min{d(y) d(x)|x,y∈V(G),d(x,y)=2}，本得到：若n阶图G的Ore2≥n 1，则G是[5;n]泛连通图。此是比Faudree等人的定理进一步的结果。     

Behavior of zirconium in the ZrOW(100) system at high temperature, studied by ISS, AES and work-function measurements

The behavior of zirconium atoms at the W(100) surface associated with oxygen adsorption at different sample temperatures has been studied by Auger electron spectroscopy (AES), ion scattering spectroscopy (ISS), and the relative change of the work function (Δф) measured by the onset of the secondary electron energy distribution. The results have revealed: (i) adsorption of zirconium onto the W(100) surface followed by the elevation of the sample temperature up to 1710 K in an oxygen partial pressure of 2.7 × 10⁻⁴ induces complete diffusion of zirconium atoms into the W(100) substrate; (ii) further exposure of oxygen induces co-existence of oxygen and tungsten on the surface at 1710 K, resulting in a work function of 4.37 eV; (iii) keeping the sample temperature at 1710 K, simple evacuation of the system has resulted in surface segregation of zirconium atoms to the surface to form a zirconium atomic layer on the top-most surface, reducing the work function to 2.7 eV. The results have revealed that this specific behavior of zirconium atoms at high temperature assures, with very good reproducibility, the highly stable performance and long service life of Zr---O/W(100)-emitters in practical use, even in a low vacuum of 10⁻⁶ Pa.     

WOx/TiO2光催化剂的可见光催化活性机理探讨

采用磁控溅射技术在用浸渍提拉法制得的TiO2薄膜上，溅射氧化钨层,通过气相反应中光催化降解二甲苯的实验表明，WOx/TiO2薄膜具有可见光活性.通过UV-Vis吸收光谱、X射线光电子能谱（XPS）等方法对其可见光活性的机理进行探索.UV-Vis吸收光谱表明WOx,TiO2对可见光响应的范围有一定的扩展,吸收强度增加.XPS表明WOx/TiO2薄膜表面形成了明显的W杂质能级和Ti缺陷能级,这是WOx/TiO2在可见光范围有一吸收的主要原因,也是光催化剂具有可见光活性的必要条件之一，同时杂质能级的存在使半导体费米能级上移,载流子增加,光催化效率提高.     

N-heterocyclic carbenes as ligands in high-valent molybdenum and tungsten complexes

Oxometal complexes of molybdenum and tungsten in high oxidation states from stable adducts with 1,3-dimethylimidazoline-2-ylidene (L) 1. The first ‘carbene’ complexes of molybdenum(VI) [MoO₂Cl(L)₃]Cl (3a) and tungsten(VI) WO₂Cl₂(L)₂ (4b) are reported.     

氧化钨薄膜微型电化学器件的研究

本文论述了WO_3薄膜氢离子敏器件的结构、原理、制备技术和测试分析。利用WO_3薄膜在H+溶液中由绝缘转化为导电特性,成功地研制成氢离子敏器件。这是一种简易而经济的微型pH敏器件技术。     

强冲击加载条件下的钨合金的界面研究

借助定量金相、扫描电子显微镜、透射电子显微镜等微观分析手段对钨质量分数为９３％的钨合金在１５～５０ＧＰａ冲击压力下微观结构响应性态进行了考察，发现了一些钨合金所特有的现象，即钨颗粒与粘结相交界处出现成分迁移，新相析出；并结合断口分析，探讨了钨合金在冲击作用下发生断裂的微观特征与韧脆转化间的关系及其物理本质。     

示波极谱法直接测定水中超痕量钨

本文对钨—溴邻苯三酚红极谱催化波进行了研究,发现体系中加入四乙基碘化铵后,极谱渡高明显增加,体系的稳定性显著提高,检出限达1.8×10~(-11)mol/L。确定了最佳条件,拟定了不经分离富集直接测定水中痕量钨的方法。此外还对极谱波性质进行了探讨,证明该极谱波为配合物吸附催化氢波,讨论了阳离子表面活性物质对催化氢波的作用机理。