电磁场能量动量张量的双矢势对偶理论

在考虑有磁荷存在的情况下，引入了电磁场双四维势的描述方法。给出了场强与双四维势的关系，并且从Euler—Lagrange方程出发，推导出了具有电磁对偶对称性的Maxwell方程；讨论了具有对偶对称性的电磁场能量动量密度张量以及它们的特性；最后，证明了有磁源存在情况下电磁场的能量和动量守恒定律。     

基于光圈控制的自动曝光算法研究

曝光是评价成像质量的关键参数之一.由于受光敏感度、自动增益等影响,光圈口径大小与亮度呈非线性关系,通过把图像分块提取亮度和测定光圈口径与亮度的关系,设计了光圈控制的非线性自动曝光算法.实验表明:采用光圈控制的非线性自动曝光算法能够实现准确、快速的曝光,并使光圈控制具有良好的稳定性.     

Li（Ni（1/3）Co（1/3）Mn（1/3））（1-x）ZnxO2固溶体的XRD及XPS研究

采用共沉淀法制备了不同Zn掺杂量的Li（Ni1/3Co1/3Mn1/3）1-xZnxO2（x=0-0.08）固溶体,通过X射线衍射（XRD）和光电子能谱（XPS）分析,研究了不同Zn掺杂量对Li（Ni1/3Co1/3Mn1/3）1-xZnxO2固溶体晶体结构和过渡金属表面化学状态的影响。实验结果表明：当Zn掺杂量x小于0.006时,固溶体材料具有稳定的层状结构;微量Zn的掺杂能够增强晶体材料的整体键能。     

锂离子电池负极SnO2的制备与电化学性能

以聚碳酸酯膜作为模板结合溶胶-凝胶技术制备snO2纳米管状阵列,用x射线衍射及扫描电镜对材料的结构及形貌进行表征,通过0.1mA·cm-2.恒流充/放电试验,研究材料的嵌脱锂特性等电化学性能.结果表明,电池最大可逆放电容量为663mAh/g,最大可逆充电容量为656mAh/g,平均每次放电容量衰减率为O.77%,平均每次充电容量衰减率为0.88%,充/放电效率维持在95%以上的稳定水平.SnO2纳米管状阵列锂离子电池负极材料克服了一般的锡氧化物循环性能差的缺点.因此有希望成为一种较好的负极材料.     

锡酸四丁酯［［Sn(OBun)4］水解缩合实验研究

本文通过锡酸四丁酯［Sn(OBun)4］Sol-Gel过程中溶胶稳定性、acacH稳定剂作用、催化剂、pH影响及溶胶体系流变学测量,提出acacH的螯合中间体Sn(OBun)2(acac)2稳定机理、催化作用机理。流变学测量发现溶胶特性粘度［η］很好地符合近似线性模型,单体官能度f≈2.0,SnO2胶粒为近似线性分子链,分型维度D≈1.80,分形结构介于SAW链和无规高斯链之间,为螯合中间体Sn(OBun)2(acac)2的存在提供了实验证据。,In this paper,it was investigated experimentally that the SnO2 sol solution stability in teh sol-gel process derived by the precursor Tetrabutyiorthostannate (Sn(OBun)4:TBOS) was dramatically influenced by stability agent Acetylacetone (acacH),catalyst species,solution pH values.Based on the experimental observations, the sol stability role of agent acacH correlated to the chelate intermediate Sn(OBun)2(acac)2 as well as catalysis mechanismi were suggested through convincing discussion.It is revealed from rheological measurements of SnO2 sol systems that the relationship between the intrinsic viscosity ［η］ and the sol solution concentration of SnO2 sol particles is in good agreement with Quasi-Linear model of macromolecules,the functionality of modified monomer f is approximately equal to 2。0,and SnO2 sol particles show themselves as quasi-linear chain.On the other hand,its fractal dimension D≈1.80,and fractal structure stands between self-avoiding walk (SAW) chain and random Gussian chain.The evidence that the chelate intermediate Sn(OBun)2(acac)2 exists in the sol-gel process is presented by this study.     

超音速电弧喷射Ag—Cu共晶熔滴的快速凝固

采用超音速电弧喷射雾化制备Ag-40％（原子分数）Cu共晶合金粉末，用X射线衍射、扫描电镜等对其凝固行为进行研究。结果表明：粉末为球形颗粒，粒径分布90％集中在15～60μm之间、平均粒径为35gm；冷却速率在10^5～10^7K／s范围，最大过冷度不小于232K；粉末富Ag相的平均点阵参数为0．401877nm，Cu的平均扩展固溶度为20．15％（原子分数），直径≤50μm时，点阵参数为0．39252nm，Cu的固溶度达到40％（原子分数），凝固组织为单相亚稳固溶体；对快速凝固行为进行了分析讨论。     

Preparation of tin-oxide nanotubes as anode for Li-ion batteries

The influence of nanostructure on the electrochemical properties of Li-ion battery was investigated. Tin-oxide nanotubes were prepared by combining sol-gel method with polycarbonate template. Scanning electron microscopy and X-ray diffractometry were applied to characterize the obtained material. The electrochemical measurements were conducted on the nanostructured tin-oxides as electrode of Li-ion batteries. The XRD data indicate that the wall of tube is composed of cassiterite crystals of several nanometers. The electrochemical measurements show that the reaction under potential 0.1-0.2 V is possibly related to the tubular structure of the material. It is suggested that the trapping of Li by dangling bonds and defects sites also contributes to the larger irreversible capacity loss in the first discharge.     

铝掺杂对富锂正极材料结构及电化学性能影响

采用共沉淀-高温烧结法制备富锂正极材料Li[Li0.20Ni0.20-x/2Mn0.60-x/2]AlxO2(x=0,0.03,0.06,0.09),考察掺铝量对材料结构及电化学性能的影响。采用X射线衍射(XRD)、透射电镜(TEM)和能谱(EDS)研究材料晶体结构和元素分布,交流阻抗及电池充放电测试电化学性能。结果表明,铝首先选择固溶在Li2Mn O3中,然后固溶在Li MO2中;掺杂铝导致材料常温下容量显著降低,高温下得到很高的可逆容量;掺杂铝2.5%(质量分数)可以极大提高材料容量保持率,并显著降低首次不可逆容量。     

Wigner function for the Dirac oscillator in spinor space

The Wigner function for the Dirac oscillator in spinor space is studied in this paper. Firstly, since the Dirac equation is described as a matrix equation in phase space, it is necessary to define the Wigner function as a matrix function in spinor space.