准正交基与保定角线性变换

引入了c-准正交矩阵、保定角线性变换等概念,讨论了保正交变换与c-准正交 变换的关系,论证了保定角线性变换与正交变换、数乘变换之间的关系。     

存在倾角的平面射流收缩及运动轨迹

通过理论推导和水力学模型实验给出了存在倾角的平面射流收缩计算模型及运动轨迹,得到了平面射流在宽度方向上的收缩角与出口速度、射流初始厚度的关系。这不仅对平面射流反应器的研究开发很有意义,而且对薄板坯连铸的研究也有一定的借鉴作用。     

Small Angle Neutron Scattering in P+-Doped Porous Silicon

On the surface of single crystal silicon wafers, porous layers can be formed by electrochemical etching and their structural properties are determined by the doping type and concentration of the substrate. In p⁺-type doped, (1 0 0) oriented wafers the porous structure consists of tube-like voids and column-like remains of the silicon matrix, all perpendicular with respect to the wafer surface. In small angle neutron scattering experiments the micrometer long and nanometer diameter elongated scattering elements, i.e., tubes and columns can be well represented and approximated by cylindrical form factors. In an earlier experiment the diameter and scattering length distribution of the cylindrical scattering elements were measured in a p⁺-type (1 0 0) oriented porous silicon wafer [G. Kádár, G. Káli, Cs. Dücsõ, and E.B. Vázsonyi, Physica B 234–236, 1014 (1997)] and the tube diameters were seen to vary in the range from about 10 to 24 nm. In this paper the continuing small angle neutron scattering study of porous silicon layers will be presented. The evaluation conditions and method for the measured neutron intensity distributions will be discussed. The pore diameter distribution data calculated from the neutron scattering intensity curves are collected and compared in various samples of (1 0 0) oriented p⁺-doped wafers prepared with different porosity and different layer depth. The structural results and data obtained by small angle neutron scattering experiments may help in understanding the practically useful chemical, electronic and other properties of porous silicon.     

利用自整角机的一种新型高精度角位移检测系统

本文介绍了一种只用单自整角机作为角位移检测元件的检测系统。系统利用sinθ和cosθ的特殊互补关系,经硬、软件的处理后获得高精度的角位移θ。实践证明这种检测方法具有精度高、反应快、检测信号稳定的特点。     

外啮合渐开线齿轮泵的困油容积

对外啮合渐开线齿轮泵困油容积的变化规律进行了理论分析，用几何法得到了求解困油容积变化量的公式．从中得出，增大齿轮分度圆的压力角可减少齿轮泵的困油．为齿轮泵的理论计算、定量分析及设计提供了理论依据，从而有助于提高齿轮泵的工作质量．     

门座式起重机门腿变形不均匀时的塔身倾角计算

建立了门座式起重机门座的空间力学模型，分析了由于荷载作用位置的非对称性造成门腿变形的非均匀性从而引起的门座顶平面及塔身的倾斜，并给出了此倾角的计算方法及计算公式。这将为门座式起重机的合理、精确设计，提供有益的参考。     

由一道力学摩擦题引起的思考

本文通过对一道滑动摩擦例题的分析讨论,归纳出具有多处摩擦的力学问题的多种解法,同时指出了一些力学教材中有关这类问题的值得商榷之处。     

凸轮机构设计的计算机绘图和动画显示

本文叙述了在凸轮设计编写计算程序时界定凸轮轮廓法向角的正确方法，并探讨了获得计算机动画显示满意效果的途径。     

开闭口角不等的综框组合运动规律的探讨

探讨了开闭口角不等的踏盘开口综框运动规律，利用综框常用的规律推导出适宜开口工艺要求的三种开口角与闭口角不等的组合式曲线方程，并对各规律作了特性分析和比较。     

晶闸管控制异步电动机节电技术的研究

本文分析了异步电动机运行时的有功损耗、功率因数与入端电压的关系,阐明了异步电动机降压运行节电的机理,并导出晶闸管控制异步电动机节电的使用条件在特定延迟角触发下控制其应用的条件。