基于ActiveX控件的多坐标轴曲线绘图

从COM技术出发,讨论了如何在VB下开发多坐标轴曲线绘图控件的方法.通过建立控件的分层对象模型,使接口的访问更加清晰,为油气田开发生产中绘制多坐标轴的复杂采油气生产曲线提供了方便、有效的工具,并应用到GIS系统.     

射频功率HBT自加热效应及补偿方法

从器件I-V特性的角度,表征了射频功率异质结双极晶体管(HBT)的自加热效应。研究了器件热阻、工作电压、电流增益、发射结价带不连续性(ΔEV)等诸多因素对器件I-V特性的影响。进而研究了为补偿自加热效应所加镇流电阻对热稳定性的改善情况,给出了器件热稳定所需最小镇流电阻(REmin)与这些因素的关系。结果表明,HBT的REmin要小于同质结双极晶体管(BJT)的REmin,因此,射频功率HBT将有更大的输出功率、功率增益和功率附加效率(PAE)。     

Data Approximation Using Biarcs

. An algorithm for data approximation with biarcs is presented. The method uses a specific formulation of biarcs appropriate for parametric curves in Bézier or NURBS formulation. A base curve is applied to obtain tangents and anchor points for the individual arcs joining in G 1 continuity. Data sampled from circular arcs or straight line segments is represented precisely by one biarc. The method is most useful in numerical control to drive the cutter along straight line or circular paths.     

Biarc approximation of NURBS curves

An algorithm for approximating arbitrary NURBS curves with biarcs is presented. The main idea is to approximate the NURBS curve with a polygon, and then to approximate the polygon with biarcs to within the required tolerance. The method uses a parametric formulation of biarcs appropriate in geometric design using parametric curves. The method is most useful in numerical control to drive the cutter along straight line or circular paths.     

Taxonomy of interpolation constraints on recursive subdivision surfaces

Published online: 14 May 2002     

曲线最佳点测设法

介绍了曲线最佳点测设法简化计算的原理、施测方法及困难地区圆曲线测设中障碍测设技巧．     

动视点的等视角变换

文章探讨了一种为二次变换的动视点的等视角变换,该变换能把直线或二次曲线变换成二次曲线或直线。文中对变换的基本性质、直线与二次曲线以及二次曲线与二次曲线的对应关系作了较详细地论述。     

超薄SiO2软击穿后I-V特性的饱和性质

利用电子速度饱和概念和比例差值方法（proportional difference operator, PDO）研究了超薄SiO2在第一次软击穿以后栅电流随着栅电压的变化所呈现的饱和性质. 实验证明了第一次软击穿以后栅电流随着栅电压变化的PDO谱峰位、峰高与电子在第一次软击穿通道中运动的饱和速度及饱和电流密度相关. 基于缺陷散射机制，得到的第一次软击穿通道的横截面积与文献报导的结果一致.     

CMOS／BESOI电特性的温度依赖性研究

采用Ｉ－Ｖ测试技术，研究了ＣＭＯＳ／ＢＥＳＯＩ器件的Ｉ－Ｖ亚阈特性与温度的关系。结果表明，随着温度的升高，Ｉ－Ｖ曲线的亚或斜率减小，且阈电压漂移增加。     

Convolutional Codes of Goppa Type

A new kind of Convolutional Codes generalizing Goppa Codes is proposed. This provides a systematic method for constructing convolutional codes with prefixed properties. In particular, examples of Maximum-Distance Separable (MDS) convolutional codes are obtained.This research was partially supported by the Spanish DGI through research project BFM2003-00078 and by the Junta de Castilla y León through research projects SA071/04 and SA032/02.