(111)择优取向的Pb(Zr0.52Ti0.48)O3铁电薄膜的制备及研究

选用不同浓度的Pb(Zr_0.52Ti_0.48)O₃溶胶，用Sol-gel法在Pt/Ti/SiO₂/Si基片上沉积一层厚度不同的Pb(Zr_0.52Ti_0.48)O₃ (PZT52)过渡层，经400℃烘烤、550℃退火等程序后，再用Sol-gel法在PZT52过渡层上沉积Pb(Zr_0.52Ti_0.48)O _{关键词： PZT铁电薄膜 择优取向 过渡层 剩余极化强度}     

碱性介质中高择优取向（220）镍电极上丙醇的电氧化

对１．０ｍｏｌ／ＬＮｉＳＯ４和０．５ｍｏｌ／Ｌ Ｈ３ＢＯ３体系，控制电位为一１．２５Ｖ，沉积６０ｍｉｎ，制得高择优取向镍电极。该镍电极经Ｘ射线衍射测定其织构度ＴＣ２２０为９２％。采用循环伏安法研究了１ｍｏｌ／Ｌ ＮａＯＨ溶液中高择翁取向镍电极上丙醇的电催化氧化机理有活性，结果表明：高择优取向镍电极对正丙醇的电催化活性高，对异丙醇的电催化活性小；推导出正丙醇的电氧化动力学方程，运用稳态极经曲线测定了     

Fabrication of PbTiO3 Ceramic Fibers by Sol-Gel Processing

The sol-gel processing was applied to the fabrication of PbTiO₃ fibers. Pb(CH₃COO)₂·3H₂O and Ti(OC₃H ₇ ⁱ )₄ were refluxed with stirring in 2-methoxyethanol to form Pb-methoxyethoxide and Ti-methoxyethoxide, respectively, followed by mixing with stirring in 2-methoxyethanol to form Pb−Ti double alkoxide. The hydrolysis and polycondensation reaction of this double alkoxide gave polymerized products, and as a result the viscosity of the solution increased, suggesting that linear polymers were produced through the hydrolysis and polycondensation reaction. Homogeneous PbTiO₃ gel fibers were drawn from the spinnable viscous solutions, which were wellcrystallized into perovskite type PbTiO₃ at 650°C. The heat-treated fibers were a few centimeters long and from 10 to 100 μm in diameter. The fiber was made up of extremely uniform grains. Electron diffraction revealed a preferred growth of (101) planes along the fiber axis, which might be due to the linear molecular characteristics of the alkoxide.     

(110)晶面全择优取向Cu镀层的制备及其条件优化

研究了添加剂聚乙二醇(PEG)、氯离子(Cl－)和电流密度对Cu的电沉积过程的影响, 着重探讨了制备(110)晶面全择优取向Cu镀层的电沉积条件及其形成机理. 循环伏安(CV)结果表明, PEG阻化Cu的电沉积, Cl－加快Cu的电沉积速率. XRD实验结果表明, PEG和Cl－在一定浓度范围有利于(110)晶面择优取向; 这两种不同特性的添加剂的协同作用可以制得(110)晶面全择优取向的较薄的Cu镀层; 所制备的全择优Cu镀层较稳定. 全择优取向Cu镀层形成的机理在于PEG和Cl－吸附过程联合起作用, 在不同晶粒的不同晶面进行选择吸附, 改变了晶面的生长速率及晶粒的快生长方向.     

衬底对Cu(In,Ga)Se2薄膜织构的影响

分别在苏打石灰玻璃、Mo箔、无择优取向的Mo薄膜以及(110)择优取向的Mo薄膜四种不同衬底上，采用共蒸发工艺沉积约2 μm厚的Cu(In,Ga)Se₂薄膜，用X射线衍射仪测量薄膜的织构，研究衬底对Cu(In,Ga)Se₂薄膜织构的影响.在以上四种衬底上沉积的Cu(In,Ga)Se₂薄膜的(112)衍射峰强度依次逐渐减弱，(220/204)衍射峰从无到有且强度逐渐增强.在苏打石灰玻璃和Mo箔衬底上的Cu(In,Ga)Se_{2关键词： 择优取向 Cu(In 2}薄膜')" href="#">Ga)Se₂薄膜 太阳电池     

速凝成晶-粘结法制备稀土磁致伸缩材料TbDyFe的研究

采用速凝成晶技术,制备了具有<112>和<110>择优取向的Tb0.27Dy0.73Fe1.95速凝片.研究发现,速凝片的择优取向和显微组织与冷却速度密切相关.随着冷却速度的增加,其择优取向从<112>向<110>变化,显微组织由枝状晶向胞枝晶转变.研究了由速凝片制备的稀土粘结磁致伸缩样品的性能.结果表明,当粉末粒度≤(100～150)μm时材料性能较好,具有<112择优取向的样品性能高于<110>择优取向的样品,磁场取向成型有利于材料性能的改善.获得了性能良好的粘结磁致伸缩材料,在238.8 kA·m-1时磁致伸缩系数达到740×10-6.     

Preparation and Ferroelectric Properties of YMnO3 Thin Films with c-Axis Preferred Orientation by the Sol-Gel Method

Hexagonal YMnO₃ has a ferroelectric property with an optimal remanent polarization along the c-axis. The c-axis oriented YMnO₃ thin films with a small leakage current were prepared by the sol-gel dipping method. The c-axis orientation of the films was promoted by the addition of diethanolamine to the Mn precursor solution. A heat treatment with multiple steps led to a dense film structure with fine grains. The dense structure resulted in the decrease of the leakage current. Furthermore, when the films were heat-treated in a vacuum, the leakage current became considerably small and the ferroelectricity of the YMnO₃ thin films was observed even at room temperature.     

Quantum calculations in a unique rest frame

The distribution of astronomical redshifts and the cosmic background radiation define a unique inertial reference frame. This paper contains an investigation of questions concerning quantum theory which arise with the introduction of a unique rest frame into spacetime. The Mössbauer effect, photon pair production, and photoelectric effect are treated together with photon scattering by a moving reflector and the Compton effect. Dirac's 1928 quantum theory of electrons is shown to yield its well-known energy spectrum for the hydrogen atom independently of the velocity of the atom relative to the rest frame.1. Address for the academic year 1990–91: 415 Graduate Studies Research Center, University of Georgia, Athens, Georgia 30602, USA.     

气相输运沉积制备c轴择优取向的碘化铋薄膜

铋基卤化物材料因其无毒和优良的光电性能而显示出巨大的应用潜力。BiI₃作为一种层状重金属半导体,已被用于X射线检测、γ射线检测和压力传感器等领域,最近其作为一种薄膜太阳能电池吸收材料备受关注。本文采用简单的气相输运沉积(VTD)法,以BiI₃晶体粉末作为蒸发源,在玻璃基底上得到高质量c轴择优取向的BiI₃薄膜。并通过研究蒸发源温度和沉积距离对薄膜物相和形貌的影响,分析了BiI₃薄膜择优生长的机理。结果表明VTD法制备的BiI₃薄膜属于三斜晶系,其光学带隙为~1.8 eV。沉积温度对薄膜的择优取向有较大影响,在沉积温度低于270 ℃时,沉积的薄膜具有沿c轴择优取向生长的特点,超过此温度,c轴择优取向生长消失。在衬底温度为250 ℃、沉积距离为15 cm时制备的薄膜结晶性能最好,晶体形貌为片状八面体。