FeMn粉末触媒对合成金刚石的影响

 利用FeMn粉末触媒在国产六面顶压机上进行了合成金刚石单晶的实验,研究了高温高压条件下（5.7 GPa、1 550 ℃）,石墨-FeMn粉末触媒体系中金刚石单晶的生长特性。通过光学成像显微镜观测表明：合成出的金刚石单晶呈浅黄色,晶形完整,且都是八面体,晶体里含有白色物质,粒度集中在0.3~0.5 mm;通过扫描电镜观测了晶体的表面形貌,表面有熔坑;通过穆斯堡尔谱,发现粉末触媒里主要是FeMn合金和独立状态的Fe,金刚石内部主要是Fe和Fe₃C;利用X射线荧光光谱,检测出样品里有Fe和Mn元素。     

爆炸压实制取W-Cu纳米复合材料的实验研究

采用机械合金化法制备了W-Cu合金粉末。将制备出的W-Cu合金粉末置于爆炸压制成型的装置中进行爆炸压实,得到了最高致密度达98%的W-Cu合金。利用X射线衍射(XRD)分析了W-Cu混合粉末的合金化过程,研究了W-Cu合金粉末的还原温度对压实坯致密度的影响。通过电子探针微量分析仪(EPMA)观察了样品内部的成分与元素分布,利用扫描电子显微镜(SEM)对样品断口形貌进行了观察,并对样品的维氏硬度和电导率进行了测量。结果表明,W-Cu合金化粉末在爆炸冲击波作用下能够结合成高致密体,复合材料具有高硬度、组织均匀、晶粒细小的特点。     

高功率脉冲非平衡磁控溅射放电特性和参数研究

用线圈电流控制非平衡磁场,用汤森放电击穿形成深度自触发放电,用磁阱捕获放电形成的二次电子和导致漂移电流,形成了高功率非平衡磁控溅射放电。采用偏压为-100V相对磁控靶放置的圆形平面电极收集饱和离子电流;在距离磁控靶14cm的位置由Langmuir探针测量浮置电位;示波器测量磁控靶的脉冲电压、电流、浮置电位和饱和离子电流信号。装置的放电脉冲功率达到0.9MW,脉冲频率最大值为40Hz左右,空间电荷限制条件是控制电子电流和离子电流的主要机制。     

Analysis of Y(4660) and Related Bound States with QCD Sum Rules

In this article, we take the vector charmonium-like state Y(4660) as a ψ'f₀(980) bound state (irrespective of the hadro-charmonium and the molecular state) tentatively, and study its mass using the QCD sum rules. The numerical value M_Y=4.71 ± 0.26 GeV is consistent with the experimental data. Considering the SU(3) symmetry of the light flavor quarks and the heavy quark symmetry, we also study the bound states ψ' σ (400-1200), Υ''f₀(980), and Υ'' σ(400-1200) with the QCD sum rules, and make reasonable predictions for their masses.     

Paramagnetism in Cu-doped ZnO

Zn0.98 Cu0.02 O powders are prepared by the sol-gel method.A small number of CuO impurity phases are observed by the x-ray diffraction,indicating the solubility of Cu in ZnO is less than 2 at.%.The Zn0.98 Cu0.02 O powders exhibit diamagnetism at 300 K and paramagnetism at 5 K.After subtracting the diamagnetic contribution of ZnO bulk and the paramagnetic contribution of defects,Cu ions exhibit weak paramagnetism.By codoping Cu with Co or Mn in ZnO,only paramagnetism is observed at room temperature.     

基于有限元法确立碳化钨顶锤的破裂判据

以有限元法为理论基础,通过运行大型有限元软件,成功构建了铰链式六面顶压机配套顶锤的有限元理论模型,并确立了碳化钨顶锤的破裂判据。模拟结果表明:以小斜边末尾处为应力参考点,依据第四强度理论,能够对碳化钨顶锤的性能进行更加合理的数值分析。依据此判据可知:在顶锤锤面及小斜边附近,裂纹高发区分布在小斜边附近;在顶锤轴向上,裂纹高发区分布在距离顶锤锤面30 mm处。铰链式六面顶压机配套碳化钨顶锤的有限元模型以及碳化钨顶锤破裂判据的成功构建,为实现新型碳化钨顶锤的设计与研究奠定了基础,对促进实现铰链式六面顶压机腔体大型化具有现实意义。     

Two Kinds of Cavity Geometry for Enhanced Laser Cooling of Solids

We present a comparison between intracavity cooling and external cavity cooling for optical refrigeration. The results show that the intracavity scheme is preferred at low optical densities （〈 0.008）, while the external cavity scheme is preferred at higher optical densities （〉 0.01）. We can choose the proper scheme for different eases in experiments. Moreover, under the same conditions, taking Yb^3＋-doped ZBLAN （ZrF4-BaF2-LaF3-AlFa-NaF） film as an example, the cooling processes of the two scheme are obtained. The calculated results show that intracavity cooling will achieve a larger temperature drop for a thin film sample. Finally, the diode laser may become a candidate for the intraeavity model briefly discussed.     

ZnH~(n±)(n=0,1,2)双原子分子离子光谱与分析势能函数研究

用密度泛函B3LYP/6-311++g(d,p)方法对ZnH~(n+)(n=0,1,2)分子离子的势能函数及光谱常数进行了分析,结果表明0价和±1价分子离子都能稳定存在而±2价离子有亚稳定态存在,其基态电子态分别为~2∑(ZnH),~1∑(ZnH~+),~1∑(ZnH~-),~2∑(ZnH~(2+)),~2∑(ZnH~(2-)),其中±2价离子的势能函数曲线明显呈"火山口"型,属于亚稳态分子离子,用八参数Murrell-Sorbie势拟合±2价亚稳态双原子分子离子势能函数得到的拟合曲线与势能扫描点符合得非常好,而四参数Murrell-Sorbie势对±2价离子的拟合与势能扫描点有较大的差距.     

用于测量熔合反应的静电偏转板介绍

An electrostatic deflector for separating the fusion evaporation residues from the beam-like products in heavy ion reactions was installed. The evaporation residue separation and identification with the electrostatic deflector setup was tested with the reaction ^32S＋^96Zr at several energies. The fusion evaporation residues and the beam-like particles were well separated after the electrical separation and the experimental fusion cross section obtained from the angular distribution is in good agreement with the calculated value well above the Coulomb barrier. This confirms the reliability of the setup.