Enhanced properties of pure alumina ceramics by oscillatory pressure sintering

A novel oscillatory pressure sintering (OPS) process to consolidate high-quality pure alumina ceramics is reported. The microstructure of the ceramics prepared by OPS develops into a higher final density, a smaller and a narrower distribution of grain sizes compared with those prepared by conventional pressureless sintering (PS) and hot-pressing (HP) processes. Enhanced mechanical properties of alumina ceramics were investigated by OPS process. The bending strength, hardness and elastic modulus of the OPS specimen reached about 546 MPa, 19.1 GPa and 374 GPa, respectively, i.e values significantly higher than that of the specimens by PS and HP. XRD analysis indicates the strengthening of atomic bonds aided by oscillatory pressure. The results suggest OPS to be an effective technique for preparing high-quality pure alumina ceramics.     

Study on Kinetics of Hydrogen Absorption by Metal Hydride Slurries Ⅰ. Absorption of Hydrogen by Hydrogen Storage Alloy MlNi_5 Suspended in Benzene

Ｈｙｄｒｏｇｅｎｓｔｏｒａｇｅａｌｌｏｙｈａｖｅａｔｔｒａｃｔｅｄｍｕｃｈａｔｔｅｎｔｉｏｎｂｅｃａｕｓｅｏｆｔｈｅｉｒｌａｒｇｅｃａｐａｃｉｔｙｆｏｒｈｙｄｒｏｇｅｎｓｔｏｒａｇｅｃｏｕｐｌｅｄｗｉｔｈｔｈｅｉｒｒｅａｄｙｒｅｌｅａｓｅｏｆｈｙｄｒｏｇｅｎａｔｍｏｄｅｒａｔｅｔｅｍｐｅｒａｔｕｒｅｓａｎｄｐｒｅｓｓｕｒｅｓａｎｄｔｈｅｉｒａｂｉｌｉｔｙｔｏｕｎｄｅｒｇｏｍａｎｙｃｙｃｌｅｓｏｆａｂｓｏｒｐｔｉｏｎａｎｄｄｅｓｏｒｐｔｉｏｎｗｉｔｈｌｉｔｔｌｅｄｅｃｒｅａｓｅｉｎｃａｐａｃｉｔｙ…     

基于FPGA的TFT LCD快检信号源的设计

目前TFT模块的生产过程中常伴有模块的线缺陷和点缺陷,依据TFF模块的驱动和测试原理,设计了一种由FPGA和模拟开关组成的集成测试信号源,该信号源可提供源极信号、栅极信号、栅极控制信号和公共地信号四路测试信号,此四路信号无论是在频率、占空比、延时,还是幅值上都满足对一般中小尺寸TFT液晶模块的线缺陷和点缺陷的测试要求,可以灵活方便地移植到其他模块测试中,具有通用性.     

Surfactant-free hydrothermal synthesis and characterization of single-crystal K2V8O21 nanobelts

Single-crystal K₂V₈O₂₁ nanobelts were prepared from the reaction between V₂O₅ and KHSO₄ under hydrothermal condition using no surfactant or template. The synthesized nanobelts were characterized by X-ray diffraction, X-ray photon-electron spectrometry, scanning electron microscopy, and transmission electron microscopy. The nanobelts are single-crystalline in nature, and have typical width of 100–500 nm, thickness of less than 100 nm and length up to a few tens of microns. The effects of solution concentration, reaction temperature and molar ratio of K and V on the morphology and phase component of the obtained products have been investigated. The possible formation mechanism was also discussed.     

曲面三角网格模型顶点法矢计算与交互式分割

本文给出一种三角网格模型顶点法矢计算公式,该公式采用网格模型中三角片面积与顶角角度综合加权,其计算精度高于现有的面积加权计算方法．另外,本文还提出了一种简便灵活的任意拓扑曲面三角网格模型交互式分割方法．利用该方法,可有效地将任意拓扑三角网格模型分割为几个与盘形拓扑同胚的区域,为后续处理提供方便。     

基于中心定位算子的遗传算法

针对遗传算法局部搜索能力弱,求解精度不高的缺陷提出了一种中心定位算子.在进化一定代数(T)后,选择最优的若干个(N)染色体基因来计算中心定位算子,从而确定与中心定位算子相同的基因位,并且在以后的交叉、变异操作中,都不让相同的基因位参与.随着算法的进行,染色体相同的基因位逐渐全部地被确定下来.其次,通过与小生境技术的局部搜索能力算法的结合,提高了该算子的全局优化能力;最后,通过几个非常容易陷入局部最优的测试函数测试表明几乎所有的峰值都得到了理论值.     

Growth of Gallium Nitride Films on Multilayer Graphene Template Using Plasma-Enhanced Atomic Layer Deposition

In this work,the GaN thin films were directly deposited on multilayer graphene(MLG) by plasma-enhanced atomic layer deposition.The deposition was carried out at a low temperature using triethylgallium(TEGa) precursor and Ar/N_2/H_2 plasma.Chemical properties of the bulk GaN and GaN-graphene interface were analyzed using X-ray photoelectron spectroscopy.The sharp interface between GaN and graphene was verified via X-ray reflectivity and transmission electron microscope.The microstructures and the nucleation behaviors of the GaN grown on graphene have been also studied.The results of grazing incidence X-ray diffraction and Raman spectrum indicate that the as-deposited sample is polycrystalline with wurtzite structure and has a weakly tensile stress.Optical properties of the sample were investigated by photoluminescence(PL) at room temperature.The successful growth of GaN on MLG at a low temperature opens up the possibility of ameliorating the performance of electronic and optical devices based on GaN/graphene heterojunction.