论弹性波绕射与动应力集中问题

本文综述了弹性波绕射与动应力集中问题的复变函数解法,给出了单连通问题、多连通问题及多裂纹问题的具体求解过程及算式.      

掺钇α-Ni(OH)_2的研究

采用均匀络合共沉淀法 ,首次合成出了掺杂钇基 α-Ni(OH) 2 .并采用 XRD,FTIR和 SEM分析技术 ,对其结构及形貌进行了研究 .电化学测试表明 ,所制得的掺杂钇基 α-Ni(OH) 2 与掺铝的 α-Ni(OH) 2 和球形 β-Ni(OH) 2 相比 ,敲实密度 1 .6g/cm2 ,电化学比容量 3 3 0 m A·h/g以上 ,活性物质利用率大于 95 % ,循环可逆性好等优点 .     

热力学理论演示装置的设计

本文设计了一种以半导体热电隅为主要元件的装置,用此装置即可演示验证热机理论,也可演示验证热泵理论。     

用易拉罐做的几个实验装置

本文介绍三种用易拉罐等旧物自制的简易实验装置。该装置具有取材方便，制作简单，造价低等优点。     

Local atomic structure of Cu(In x Ga1−x )Se2 (x = 0.25, 0.5, and 0.75) systems for solar cells

The local atomic structure of thin surface layers of crystalline quasi-binary Cu(In _x Ga_1?x )Se₂ solid solutions was studied by SIMS and EXAFS techniques. The SIMS method showed that the elemental composition of the sample changes most significantly in thin layers at a depth of 5–10 nm; in deeper layers, the component concentrations correspond to the bulk values. The EXAFS method in the x-ray fluorescence mode showed that the results obtained are in agreement with the assumption that quaternary crystalline quasi-binary Cu(In _x Ga_1?x )Se₂ solid solutions exhibit local disorder while average long-range order is detected from x-ray diffraction data.     

Electronic and optical properties of ZnO thin film under in-plane biaxial strains: Ab initio calculation

The full regions of the electronic and optical properties of in-plane biaxial strained thin film ZnO are studied using pseudopotential plane-wave method. The fundamental band gap at the Γ point increase linearly with the increase of tensile strains, but decreased with the compressive ones. The strains affected the local tetrahedral symmetry, and so the splitting of crystal field energy. The band dispersion relation of the valence band maximum changes with the strains, which means the residual strains have effects on the effective hole mass, thus the transportation properties of the p-type ZnO. The changes tendency of optical properties up to full regions under strains have been shown and discussed.     

Calibration and use of hot wire probes for steady state measurements in low density flows

In recent years the use of hot wire probes for steady state measurements in low density flows has proved very valuable in extracting information concerning flow properties. In interpreting hot wire measurements in low density flows, it is imperative that the heat loss to the wire supports be accurately taken into account. In the present paper, a detailed analysis and calibration procedures for the direct evaluation of the end-loss correction factors for a moderate aspect ratio hot wire have been set out, and experimental verification done to establish the validity of the technique.     

A r -Weighted Poincaré-Type Inequalities for Differential Forms in Some Domains

We prove local weighted integral inequalities for differential forms. Then byusing the local results, we prove global weighted integral inequalities for differential forms in L _s (μ)-averaging domains and in John domains, respectively, which can be considered as generalizations of the classical Poincaré-type inequality.     

基于最小二乘的工程结构边界载荷反求误差消减方法

机械装备工程结构强度计算和疲劳寿命预测等都需要准确获知结构的工作或边界载荷。然而,由于土壤和砂石等工作介质的切削及铲运等精确阻力模型难以建立,以及机械装备动力传动过程中的摩擦等损耗难以精确计算,导致准确获得装备工作结构的边界载荷非常困难。依据圣维南原理,采用有限元法建立复杂结构中局部结构应变与其边界载荷的关系,对边界载荷反求过程中误差来源和范围进行了分析和估计,提出了基于最小二乘法的复杂结构局部边界载荷误差消减方法。对推耙机横梁结构的边界载荷进行分析,验证了该误差消减方法的有效性。