Bi_4Ti_3O_(12)薄膜的结构与形貌分析

采用金属与金属氧化物复合靶的射频溅射法,在S_1,Au,Pt和Ti基片上沉积制备Bi_4Ti_3O_(12)(BTO)铁电薄膜,对不同基片沉积的BTO薄膜,以及不同退火温度下的薄膜的相结构、成分及形貌进行了分析。结果表明,BTO薄膜的结构与退火温度和沉积基片有关,不同基片上钙钛矿结构形成的温度按T_t相似文献   

含1，2，3－噻二唑环硫脲的合成及结构鉴定

含１，２，３－噻二唑环硫脲的合成及结构鉴定司宗兴，董燕红（中国农业大学应用化学系，北京１０００９４）作者根据：（１）硫脲分子中氮原子与硫原子电子的ｐ－π－ｐ共轭效应与生物活性关系；（２）硫原子取代脲中氧原子后，毒性降低的一般规律；（３）氮原子上不同苄...     

光纤模式混合器在差分吸收光谱系统中的应用研究

差分吸收光谱技术(DOAS)已经发展为监测对流层痕量气体的重要技术，一般采用光电倍增管(PMT)作为探测器.由于光电二极管阵列(PDA)在多道探测及像元灵敏性方面的优势，采用PDA代替扫描探测装置将能改善系统剩余噪声，提高系统性能.但实际应用中由于使用收发一体Cassegrain望远镜造成灯谱与大气谱结构不统一，在消除PDA像元间差异的过程中给系统带来误差，从而导致剩余噪声的标准偏差达到1.4×10^-3.根据光纤扰模原理在系统中加入自制光纤模式混合器很好的解决了上述难题，在实际应用中起到良好的作用，系统剩余噪声的标准偏差为3.4×10^-4. 关键词： 差分吸收光谱 扰模 模式混合器 剩余噪声     

自然循环回路内芯片的强化沸腾换热研究

针对电子器件的高效冷却问题,对自然循环回路系统内表面加工有方柱形微结构的硅片上FC-72的强化沸腾换热性能进行了实验研究.测试了两个芯片,其表面上的方柱形微结构的边长均为30μm,但高度分别为60 μm和200 μm.沸腾介质的过冷度设为10 K、25 K和35 K.随着壁面过热度的增加,微结构表面芯片上的热流密度急剧增加且临界热流密度时芯片的表面温度低于芯片回路正常工作的临界上限温度85℃,这与其在池沸腾换热中的特点一样.但临界热流密度值与池沸腾情况相比有所降低.     

钢管和有机玻璃管油水两相摩擦压降比较实验

本文对水平放置的内径为40 mm的钢管和有机玻璃管内的油水两相流动摩擦压降特性进行了比较实验研究.从实验方面含水率和混合流速等因素对钢管和有机玻璃管内油水两相油滴分散流摩擦阻力压降规律的影响进行了详细研究.实验结果表明:含水率和混合流速是影响压降的主要因素;在本实验范围内,除了分层流区域以外,有机玻璃管内的油水两相摩擦阻力压力梯度大于钢管内油水两相摩擦阻力压力梯度.     

Photoluminescence Property of Co3O4 Nanowires

Co3O4 nanowire arrays are fabricated by electrodeposition with following heat-treatment in atmosphere ambient. Photoluminescence is investigated at 295K. In the experiment, when increasing the excitation light wavelength from 260 nm to 360 nm, two kinds of emissions corresponding to the increasing excitation light wavelength are observed. One of them alters the excited emission position, another keeps its emission position. The distinct behaviour of excited emissions related to the increasing excitation wavelength indicates that the mechanism of them must be different. According to the experimental comparison and first-principle calculation, the two kinds of emissions are discussed.     

Development of the Technique for Fabricating Submicron Moire Gratings on Metal Materials Using Focused Ion Beam Milling

A focused gallium ion （Ga＋） beam is used to fabricate micro/submicron spacing gratings on the surface of porous NiTi shape memory alloy （SMA ）. The crossing type of gratings with double-frequency （25001/mm and 50001/mm） using the focused ion beam （FIB） milling are successfully produced in a combination mode or superposition mode. Based on the double-frequency gratings, high-quality scanning electron microscopy （SEM） Moird patterns are obtained to study the micro-scale deformation of porous NiTi SMA. The grating fabrication technique is discussed in detail. The experimental results verify the feasibility of fabricating high frequency grating on metal surface using FIB milling.     

First-Principles Study of Structural and Electronic Properties of Layered B2CN Crystals

Based on the hexagonal BN structure, six possible layered B~ CN structures are constructed. Their total energies, lattice constants as well as electronic properties are calculated using the ab initio pseudopotential density functional method within the local density approximation. The calculated results show that the B2 CN-V configuration with AA stacking sequence is the most stable among the six B2CN layered structures. The characteristics of electronic structures indicate that the B2 CN-V shows metallicity, which mainly comes from -B1-C-B1-C- chains.