强流脉冲电子束作用下纯镍表面的应力特征

 利用强流脉冲电子束（HCPEB）装置对多晶纯镍进行轰击,采用X射线衍射及扫描电子显微镜等技术,详细分析了受轰击样品的变形组织与结构。通过分析建立了强流脉冲电子束诱发的应力特征与变形结构之间的关系,并对目前现有的几种应力波数值模拟结果进行了讨论。实验结果表明：强流脉冲电子束能够在材料表层诱发约5GPa的应力,造成纯镍表面发生孪生塑性变形。除了热膨胀引起的表层横向准静态热应力外,强流脉冲电子束产生的等离子体脉冲爆炸可以直接诱发幅值很高的冲击应力波,二者的共同作用是引起表层微观结构变化的直接原因。     

金属Nb中H的量子行为研究

采用基于密度泛函原理的赝势平面波方法,计算了H在Nb晶体中的势场.通过求解H在该势场中的Schrdinger方程,得到了H的振动状态.计算结果表明,H的基态和第一激发态是局域的,第二激发态是非局域的,可以在T点之间迁移以及做4T/6T环运动. 关键词： 第一性原理 金属氢化物 量子振动     

High-Pressure and High-Temperature Behaviour of Gallium Oxide

High-temperature and high-pressure behaviours of β-Ga2O3 powder are studied by energy-dispersive x-ray diffrac- tion in a diamond anvil cell （DAC）. It is found that the phase transition from the monoclinic β-Ga2O3 to the trigonal α-Ga2O3 occurs at around 19.2 GPa under cold compression. By heating the powder to 2000 K at 30 GPa, we confirm that α-Ga2O3 is the most stable structure at the high pressure. Furthermore, the structural transition from β-Ga2O3 to α-Ga2O3 is irreversible. After laser heating, the recrystallized Ga2O3 has a preferable （012） orientation. This interesting behaviour is also discussed.     

Phase Transition and Optical Properties of Solid Oxygen under High Pressure: A Density Functional Theory Study

Crystal structures and optical properties of the δ-O2 phase and the ε-O8 phase have been investigated by using the ab initio pseudopotential plane-wave method. It is found that the phase transition is of the first order with a discontinuous volumetric change from the antiferromagnetic δ-O2 phase to the nonmagnetic ε-O8 phase, consistent with the experimental findings. The energy band calculations show that the direct band gap changes into an indirect band gap after the phase transition. The apparent change in the optical properties can be used for identifying the phase transition from δ-O2 to ε-O8.     

Synthesizing of ZnO Micro/Nanostructures at Low Temperature with New Reducing Agents

Instead of the conventional graphite, new additional reducing agents （diamond, silicon, metal elements, etc.） have been mixed with zinc oxide （ZnO） powder to fabricate ZnO micro/nanostructures by a thermal vapour transport method. Due to the strong reducibility for those additions, the corresponding heating temperature is decreased by 100 500℃ compared to the case of graphite, which subsequently decreases the corresponding growth temperature for the products. Being placed separately for the powder sources of ZnO and addition, a vapour-vapour reduction-oxidation reaction mechanism between the sources is proposed as an important channel to fabricate ZnO. Photoluminescence and magnetic examinations indicate that the ZnO products synthesized have strong ultraviolet （visible） emissions and are room-temperature ferromagnetic, meaning that the products are available for applications.     

一套高温高压原位拉曼散射、布里渊散射测量系统

本文描述了一套利用激光加热技术、金刚石对顶砧高压技术,集成共聚焦拉曼光谱测量、六通道布里渊散射光谱测量、以及黑体辐射光谱测温,成功搭建起来的高温高压原位拉曼散射、布里渊散射的光学测量系统。利用该系统,并结合薄膜沉积金属、光刻技术改进了金刚石对顶砧中样品的装填方法,解决了样品透明不易加热的问题。已利用该系统得到液态氩在0.85 GPa常温状态下和14.58 GPa熔融状态下的体声速分别为1.85 Km/s和5.19 Km/s。     

YBa_2Cu_3O_(7-δ)超导体在不同气氛中的高温相变

本文给出了在空气、真空和流动氮气的环境中,利用X-光跟踪监测YBa_2Cu_3O_(7-δ)高T_c超导体的X-光衍射峰的两个主要峰(130)/(101)和(031)峰的相对强度随温度的变化关系。结果表明,环境对高温相变温度及相变方式有很大的影响。并提出了“可动氧”模型。     

4GPa下固体等温状态方程的测定

本文在活塞—圆筒装置下,通过测量活塞位移的方法,测定了Bi_(1-2)和Bi_(2-3)的相变压力及4GPa下的铝和石墨的等温状态方程。我们的结果与Kennedy等人的结果相当一致。     

磁控弧光放电增强等离子体离子镀合成c－BN薄膜

采用能产生高密度等离子体的磁控弧光放电增强等离子体离子镀的方法，制备立方氮化硼（ｃ－ＢＮ）薄膜．     

快速生长金刚石薄膜的装置及其工作性能

本文设计了用直流电弧等离子体喷射法快速生长金刚石薄膜的装置,并对其工作性能进行了研究。