高频介质系统介电性能与相组成的定量关系分析

采用普通电子陶瓷工艺制备两种高频介质系统ZnO-B2O3-SiO2三元系和BaO-PbO-Nd2O3-Bi2O3-TiO2五元系,通过XRD分析确定各系统的主晶相, 运用衍射峰强度计算法准确测定出各组分的体积百分含量,并代入Lichnetecker对数混合定则,计算出系统的介电性能,获得了分析介质系统介电性能与物相含量之间定量关系的新方法.     

SINGLE AND DOUBLE EDGE INTERFACE CRACK SOLUTIONS FOR ARBITRARY FORMS OF MATERIAL COMBINATION

In this paper interfacial edge crack problems are considered by the application of the finite element method. The stress intensity factors are accurately determined from the ratio of crack-tip-stress value between the target given unknown and reference problems. The reference problem is chosen to produce the singular stress fields proportional to those of the given unknown problem. Here the original proportional method is improved through utilizing very refined meshes and post-processing technique of linear extrapolation. The results for a double-edge interface crack in a bonded strip are newly obtained and compared with those of a single-edge interface crack for different forms of combination of material. It is found that the stress intensity factors should be compared in the three different zones of relative crack lengths. Different from the case of a cracked homogeneous strip, the results for the double edge interface cracks are found to possibly be bigger than those for a single edge interface crack under the same relative crack length.     

Temperature Dependence of Integrated Intensity Bands in IR-Absoption Spectra of (NH4)2AF6 Complexes

The contribution refers to the temperature dependence of IR-absorption spectra (NH₄)₂AF₆ (A - Si and Ge). It is found that with temperature decreasing, the integrated intensities of the bands corresponding to anion fundamentals, increase, while those of cation, decrease. An explanation is given to the phenomena detected, which is based on variations in the strength of the outer-sphere interaction with the temperature, and subsequent redistribution of electron density.     

三维动态裂纹问题的超奇异积分方程法

基于弹性材料的动态基本方程，结合广义Betti-Rayleigh互易等式与时域下的边界积分方程，推导得到时域下的超奇异积分方程组。引入Laplace域下的动态基本解，将经过主部分析的积分核函数分解为静态和动态部分，其中动态积分核不具有奇异性。在裂纹前沿附近单元，采用与理论分析一致的平方根位移模型。结合Lubich时间卷积实现拉氏变换，采用配置点法计算超奇异积分，获得问题的数值解。并针对椭圆裂纹算例编写Fortran程序，得到冲击荷载作用下张开型裂纹的动态应力强度因子变化规律，数值结果稳定且收敛速度快。     

N2 Laser Excited Fluorescence of Oxalyl Chloride at 77°K

The N₂ laser excited fluorescence spectrum and the intensity of fluorescence of oxalyl chloride C₂O₂Cl₂) condensed at 77°K either alone, or, diluted with a non-hydrocarbon or a hydrocarbon with dilution ratios ranging from 10 to 100 were studied. A slow condensation of the hydrocarbon matrix diluted sample showed a considerable reduction in the fluorescence intensity as compared to a fast condensation of the same sample.     

Infrared Spectrum of the Cyclopentylmethyl Free Radical

Abstract

The cyclopentylmethyl free radical has been generated in argon matrices by UV irradiation of the corresponding diacyl peroxide at T = 20K. The infrared spectrum of the radical reveals an out-of-plane deformation of the radical center at 563 cm^?1 characteristic of primary alkyl radicals.     

Characteristic material parameters of CIGS solar cell related with device performance

CIGS solar cells with power conversion efficiency (PCE) in the range of 1.82%–12.30% were obtained by using two-step process, and were further analyzed through various measurement techniques. Material parameters showed diverse values and some trends depending on the device performance. The lower performance device showed small integrated PL intensity, short minority life time, larger defect density and lower activation energy, whereas the higher performance device showed opposite values. We investigated relationship between material parameters and PCE of solar cells, and found that some physical parameters such as integrated PL intensity, minority life time, defect density, and difference between band gap and activation energy (E_g-E_a), which all reflect defect states in bulk and at pn interface, are strongly related with PCE and would be used as a good indicator to evaluate device performance quickly.     

Three-dimensional interfacial fracture analysis of a one-dimensional hexagonal quasicrystal coating

In this paper, the three-dimensional (3D) interfacial fracture is analyzed in a one-dimensional (1D) hexagonal quasicrystal (QC) coating structure under mechanical loading. A planar interface crack with arbitrary shape is studied by a displacement discontinuity method. Fundamental solutions of interfacial concentrated displacement discontinuities are obtained by the Hankel transform technique, and the corresponding boundary integral-differential equations are constructed with the superposition principle. Green’s functions of constant interfacial displacement discontinuities within a rectangular element are derived, and a boundary element method is proposed for numerical simulation. The singularity of stresses near the crack front is investigated, and the stress intensity factors (SIFs) as well as energy release rates (ERRs) are determined. Finally, relevant influencing factors on the fracture behavior are discussed.