电化学沉积Mn掺杂纳米ZnO的结构和光学性质的研究

在Si衬底上用电化学沉积方法制备了Mn掺杂ZnO纳米晶X射线衍射（XRD）的研究表明,Mn离子取代Zn离子进入到 ZnO晶格中。场发射扫描电子显微镜（SEM）图像显示,ZnO纳米晶形貌的是柱状的。从光致发光谱可以看出,由于掺杂效应导致了可见发射带扩大, PL谱从122.8k到302.2k范围的拟合结果表明,Mn掺杂导致的激子结合能的降低。     

电化学沉积Nd掺杂ZnO薄膜的结构和光学性质的研究

用电化学沉积方法制备出了Nd掺杂的ZnO薄膜,并研究其结构和光学性质。X-射线衍射谱的结果表明Nd3 替代Zn2 进入到ZnO晶格中,并没有引起杂相的出现。吸收谱的分析表明,随着掺杂浓度的增大,吸收峰向短波长方向移动 ,即发生蓝移。光致发光谱的结果表明随着Nd3 掺杂浓度的增大,紫外峰强度减小,可见光部分强度增大了。     

Hydrodynamics and mass transfer in carbon-nanofiber/graphite-felt composite under two phase flow conditions

A carbon nanofiber (CNF)/graphite felt composite was synthesized by growing CNFs on the surface of graphite fibers and was used as the packing of a fixed bed reactor under two phase flow conditions. The pressure drop, axial dispersion and mass transfer in the liquid were studied by experiment and by piston dispersion exchange (PDE) model. It was shown that the pressure drop and total liquid up could be predicted by the slit model in an acceptable accuracy. The axial dispersion in the liquid phase in the composite and the mass transfer between the dynamic and static liquid are higher than in the packed bed of solid particles owing to the porous and fluffy CNF layer on the carbon felt fiber.     

基于各向异性损伤的厚壁圆筒应力分布有限元分析

围岩的应力分布影响地下硐室的稳定。基于各向异性损伤理论研制了相应的轴对称有限元程序，分析了厚壁圆筒在外压作用下的应力分布。围岩的切向应力梯度随着材料脆性指数的增加而增大，厚壁圆筒临近整体破坏时，最大切向应力位于距筒壁内表面一定深度处。研究结果较好地解释了岩爆剥落岩片存在一定厚度这一现象的力学机制。