Structural and Electrical Characteristics of Pb（Zr0.53,Ti0.47）O3 Thin Films Deposited on Si （100） Substrates

Pb(Zr0.53, Ti0.47)O3 (PZT) films were directly deposited on Si substrates without a buffer layer by pulsed laser deposition. Only(110)-oriented PZT peaks (other than Si substrate peaks) were observed from the XRD data. The electrical properties of the PZT/Si capacitor were characterized in terms of both the capacitance versus voltage (C-V) and current versus voltage (I-V) measurements. The clockwise trace of the C-V curve shows ferroelectric polarization switching, as is expected. From the I-V curves, the Schottky emission and spacecharge-limited-current behaviour are found to be the mainly leakage current mechanism in a certain electric field range in the negative and positive bias, respectively.     

一类图的特征多项式与匹配多项式

本文对一类具有对称轴的图A_n(n≥0),得到了它的特征多项式及匹配多项式的精确表达式;同时还得到A_(?)的完美匹配数。     

Structural Characteristics of Liquid Sn

We investigate the structural properties of liquid Sn. With the help of the internal friction (tanФ) method, it is found that a peak appears in the tan Ф - T curve, suggesting that an anomalous discontinuous temperatureinduced structure change may take place in liquid Sn. From the experimental data of pair distribution functions, we calculate the viscosity η and the excess entropy S and it is found that there are a peak of viscosity in the η-T curve and a bend of excess entropy in the S - T curve, which give a positive support to the appearance of the internal-friction peak in the tan Ф- T curve.     

CL-18的合成

CL-18是根据TATB和BTF两种化合物的分子结构特征所设计并已合成的，其分子兼具TATB和BTF的分子特征，一方面，氨基的推电子效应使C-NO2键能增强，又由于氨基与硝基的氧原子间形成强的分子内和分子间氢键，更增强了分子的稳定性，因而具有优良的热稳定性和较低的感度。另一方面，分子中引入氧化呋咱基团，可明显提高化合物的密度和爆轰性能。在钝感冲击片雷管和钝感传爆药中具有潜在的应用前景。     

用GSP进行"波动"教学案例

学生的学习需求是指学生要达到的目标水平与他现在实际水平之间的差距．本课的教学目标是：了解波的形成条件及过程、波的种类、振动和波的关系；理解波的传播规律和波的图象．学生的实际是只学过振动和振动的图象，会使用《几何画板》软件．此差距很明显．这就要求教师根据建构主义学习理论，通过创设情景、搭脚手架来降低知识的梯度，真正把教学目标转化为学生自己的学习需求．     

Theoretical analysis of the acoustical characteristics of suspended micro-perforated panel absorbers

Sound absorption characteristics of suspended micro-perforated panel absorbers were investigated theoretically. The method of half thickness model of such panel absorber with quadripole analysis was used for predicting its acoustic performance. The analysis results show that the predictions agree well with the measurements of absorption in the reverberation chamber. The factors affecting the absorption characteristics for such absorbers were discussed, and some rules as design guidelines were given.     

Fractal Character for Tortuous Streamtubes in Porous Media

An analytical model for fractal dimension of tortuous streamtubes in porous media is derived. The proposed fractal dimension for tortuous streamtubes in porous media is expressed as a function of porosity and scale, and there is no empirical constant in the proposed expression. The model predictions for the fractal dimension of tortuous streamtubes in porous media are in good agreement with those by the box-counting method and with the observations of other researchers.     

高阶特征线性及其与semi-Lagrangian方法的比较

特征线性与semi-Lagrangian方法都是处理流体方程时间离散的两种有效的方法．它们比经典的半隐格式，如Backward-Euler／Adams-Bashforth方法有更好的稳定性．本提出一种基于高阶空间离散的特征线法，通过稳定性，精度和计算复杂性与semi-Lagrangian方法进行比较，分析了高阶特征线法的有效性和适用性，并从数值试验上对分析结果进行验证．     

Theoretical Analysis of Characteristics of GaxInl—x NyAsl—y／GaAs Quantum Well Lasers with Different Intermediate Layers

Based on the band anticrossing model, the effects of the strain-compensated layer and the strain-mediated layero n the band structure, gain and differential gain of GalnNAs/GaAs quantum well lasers have been investigated. The results show that the GaNAs barrier has a disadvantage in increasing the density of states in the conduction band. Meanwhile, the multilayer quantum wells need higher transparency carrier density than the GalnNAs/GaAs single quantum well with the same wavelength. However, they help to suppress the degradation of the differential gain. The calculation also shows that from the viewpoint of band structure, the strain-compensated structure and the strain-mediated structure have similar features.     

高应变率下U-Nb合金的断裂组织特征

利用内部爆炸加载方法对U-Nb合金进行爆破试验，对爆破试验产生的破片进行回收，并对U-Nb合金破片进行一些微观检测分析，从而初步研究在爆炸加载下U-Nb合金的微观断裂机制。