Depolarization and Electrical Response of Porous PZT 95/5 Ferroelectric Ceramics under Shock Wave Compression

The release of bound charges by shock wave loading of poled lead zirconate titanate （PZT 95/5） ferroelectric ceramics can result in a high-power electrical energy output. In this study, a theoretical formulation describing the depolarization and electrical response of porous PZT 95/5 ceramics in the normal mode to shock wave compression loading perpendicular to the polarization direction is developed. The depoling process in porous poled PZT 95/5 ceramics is analyzed by using a parallel circuit consisting of a current source, capacitance, conductance and a circuit load. This modeling takes the effects of porosity on wave velocity and remanent polarization and dielectric constant into account, and the effects of variations in dielectric constant and conductivity in the shocked region are assessed. The output current characteristics of porous PZT 95/5 ceramics under short-circuit and resistive load conditions are analyzed and compared with the experiment, with the results showing that theoretical predictions taking into consideration the porosity of ferroelectric ceramics are in close agreement with the experimentally measured electrical response of porous PZT 95/5 under shock wave compression loading.     

An analytical model for coplanar waveguide on silicon-on-insulator substrate with conformal mapping technique

In this paper, the authors present an analytical model for coplanar waveguide on silicon-on-insulator substrate. The four-element topological network and the conformal mapping technique are used to analyse the capacitance and the conductance of the sandwich substrate. The validity of the model is verified by the full-wave method and the experimental data. It is found that the inductance, the resistance, the capacitance and the conductance from the analytical model show they are in good agreement with the corresponding values extracted from experimental S-parameter until 10 GHz.     

Extended Conservation Laws of Some Nonlinear Partial Differential Equations

Self-adjoint theorem is introduced to match the corresponding functional of the given differential equations,and then Noether＇s theorem is used to determine the extended conservation laws of the original equations. Finally, as the application of the method, the conservation laws of Drinfel＇d-Sokolov-Wilson equation and Benjamin-Bona-Mahony equation are constructed.     

ZnO/PAMAM G5.0的合成及其对“502”熏显处理指印的增显作用研究

为了同时解决纳米指印显现试剂的灵敏度、专属性以及安全性等方面的问题,设计出氧化锌/聚酰胺-胺树形分子纳米复合材料(ZnO/PAMAM G5.0)的构架,并探索了相关的合成条件、产物的荧光性能及其在潜指印显现方面的应用前景。实验结果表明,ZnO纳米颗粒可以在PAMAM G5.0树形分子的模板作用下控制生成;合成产物在中波紫外光的激发作用下可以发出蓝色可见光;当锌离子与树形分子的负载比介于10~100范围内时,合成产物的荧光性能呈现先增长后下降的趋势,并在负载比为60时得到最强光致发光效果;对于经"502"熏显法固定后的潜指印样本,ZnO/PAMAM G5.0纳米复合材料可以通过胺解反应途径对其进行有效的增显。ZnO/PAMAM G5.0纳米复合材料有望引领纳米指印显现试剂新的发展方向。     

13个省、自治区滩涂湿地木霉菌分布初探

从13个省、自治区的滩涂湿地中采集了土壤和水样品共计837份,从中分离出了827株木霉菌株。实验结果表明,土壤样品比水样更容易分离到木霉菌,且土壤样品中的含盐量越低越容易分离到木霉菌。海拔高度也是影响木霉分布的因素,海拔高度在100 ～ 1 200 m之间木霉的分离率最高,这可能与该海拔区间中的植被相对丰富有关。     

船用交错轴变厚齿轮啮合性能的研究

基于空间齿轮啮合原理和有限单元法,分别建立了船用交错轴变厚齿轮齿面模型及啮合模型.在承载和安装误差的作用下,对船用交错轴变厚齿轮传动啮合特性进行了分析,研究了中心距误差、轴交角误差和大齿轮轴向位置误差对啮合印痕、最大接触压力、传动误差及啮合刚度的影响规律.结果表明,中心距和轴交角误差使得啮合印痕发生明显的偏移,造成最大接触压力及传动误差的峰峰值增加,且中心距及轴交角的正负误差对啮合刚度的影响呈相反的趋势,但大齿轮轴向位置的误差对啮合特性影响较小.通过加载啮合特性试验,验证了理论啮合分析结果的正确性,这对船用交错轴变厚齿轮传动匹配设计具有重要的指导意义.     

基于刀具法向基准的奥利康准双曲面齿轮精确建模与验证

基于奥利康制准双曲面齿轮切齿原理和加工方法,分析了三面刀刀头的结构和安装位置,提出了基于刀具NS(neutral surface)平面法向基准下刀盘数学模型的建立方法。在此基础上,推导了奥利康制准双曲面齿轮的加工机床坐标系,建立了成形法大轮和展成法小轮的齿面数学模型,整理了一套基于三面刀盘奥利康制准双曲面齿轮精确化建模流程。通过齿面模型得到的数学齿面与通过KIMOS软件得到的45点齿面进行对比和实际接触印痕与理论接触印痕对比两种方法进行齿面验证。结果表明:大小轮推导齿面与实际齿面齿线和几何形貌基本一致,小大轮齿面基本重合;小轮凹面最大误差位于小端偏齿顶处,其值为0.007 5 mm,大轮凸面最大为0.002 3 mm;KIMOS计算的理论轮齿接触分析(TCA)、轮齿承载接触分析(LTCA)印痕与有限元计算印痕的位置方向基本一致,验证了齿面的正确性。     

刘备和宋江

《三国演义》和《水浒传》是吸收中国古代文化深厚滋养而孕育成的两部不朽的古典杰作.从明初成书至今六百年以来,以小说为依据的三国故事和水浒故事在社会各阶层中广为传播,经久不衰;书中所极力歌颂的两个主要(中心)人物——刘备和宋江,更是家喻户晓,妇孺皆知.甚至在某些方面还为今天的人们所效     

薄膜法在X射线荧光光谱分析中的应用痕量稀土分量测定

本文提出了一种新型的薄膜法,可应用于工艺流程控制及地质样品中稀上分量的测定。具有制样简单,背景低,消除吸收增强效应,工作曲线线性范围大等优点。本实验室制备了一种以6卢Mylar膜为衬底,在上面再覆盖一层PMBP(1—苯基—3—甲基-4-苯甲酰-5吡唑酮)(稀土元素的优良萃取剂)的薄膜。在该膜上可一次完成常规的分离和富集过程,并制备出适合于X荧光测定的薄试样。因而大大加快了分析速度。同时该薄膜萃取剂还可应用于其它元素的分析上。