基于Auto CAD的工程制图三维模型库的开发及应用

本文讨论了工程制图三维模型库的作用以及它对教学改革的影响,并基于Auto CAD所建立的工程制图虚拟模型库特点及制作要领进行介绍.     

贵州教育学院图书馆用户信息需求调查与分析

对贵州教育学院图书馆用户信息资源需求和信息服务需求现状进行调查与分析,提出我院图书馆应从加快信息资源建设、优化馆藏结构、提高服务质量和提高馆员素质三个方面开展工作,来构建及调整信息资源体系与信息服务体系,满足用户的信息需求。     

网络环境下的高等教育管理改革

在网络环境下,高等教育管理已在教学管理、教师管理、实验管理、资料管理等方面进行了改革,这对高等教育的全面发展起到了非常重要的作用。     

对建设规范高效的高校图书馆的思考

传统的高校图书馆低效、被动地提供有限的服务，越来越不能适应蓬勃发展的高等教育的要求。在新形势下，应当精简机构，建立高效的服务体系，完善管理制度，树立读者第一的服务宗旨；组建高素质的队伍，提供优质的服务。     

Comparison study of harmonic imaging (HI) and fundamental imaging (FI) in fetal echocardiography

Objectives: To directly compare the quality of harmonic imaging (HI) and fundamental imaging (FI) in fetal echocardiography and to determine any differences in image quality between the two modalities. Methods: Fetal echocardiograms were performed with the use of FI and HI in 58 fetuses, image quality and visualization of left and right atria, left and right ventricles, mitral and tricuspid valves, aortic and pulmonary valves, left and right ventricular outflow tracts were evaluated and compared between FI and HI. Results: Mean HI scores were higher than mean FI scores (2.73±0.43 vs 2.16±0.69, P<0.001)for all the cardiovascular structures evaluated. Compared with FI, HI improved the image quality and visualization of fetal cardiac structures in subjects with both good (2.73±0.43 vs 2.88±0.32, P<0.001) and suboptimal (1.65±0.41 vs 2.58±0.47, P<0.001) echocardiographic windows. The interobserver correlation coefficient for the grading scores was 0.74 (P<0.001). Conclusions: harmonic imaging enhances and improves the image quality of fetal echocardiography; and has important potential role in cardiac imaging in the fetus.     

关于地质时间本质的思考

通过对新疆北部志留—泥盆系界线的讨论，以及对乌吐布拉克组的地层归属问题的探讨，和国际志留—泥盆系界线的理论根据的浅析，提出地质时间本质的含义。     

数字图书馆与图书馆人员的继续教育

电大图书馆作为现代远程开放教育的资源中心，是学校进行远程开放教学的重要组成部分，是为教师和学生提供支持服务的重要阵地。近年来，电大数字化图书馆的建设无疑对图书馆管理人员的素质提出了新的要求。图书馆管理人员惟有提高认识，积极投身到继续教育的行列中，不断提高信息服务技能，才能适应形势发展的需要。     

Pressure angle in parallel mechanisms: From planar to spatial

This paper presents the evolution process of pressure angles from planar parallel mechanisms to spatial parallel mechanisms. Manipulability and condition number, which are frequently used in the optimum design of parallel mechanisms, are introduced from serial robots at first. Then, both theoretical analysis and practical experiences demonstrate that these concepts seem imperfect when they are used in parallel mechanisms. For this reason, this paper introduces the pressure angles in planar 4-bar mechanisms to spatial parallel mechanisms, which include redundant parallel mechanisms. Two kinds of pressure angles extracted from the determinant of direct and indirect Jacobian matrices are investigated. Moreover, two comprehensive and visible global performance indices are defined, showing the advantages in evaluating the workspace, singularity and motion/force transmission capabilities. With a 2-DOF planar and a 3-DOF spatial parallel mechanism as examples, the application of the performance indices is investigated and compared with the condition number at last. The proposed concept can be extended to other spatial parallel mechanisms.     

关于诚信美德再认识的几点看法

从古至今，中国人一直把诚信作为高尚的人格特征贯穿于中华民族道德发展的历史长河中。在市场经济的新形势下，要求我们对传统诚信思想的特点及其现代价值有一个深刻的认识。     

旋转二次曲面成像公式的两种新推导方法

利用折射定律和旋转二次曲面在直角坐标系下的统一方程，分别导出了旋转二次曲面在近轴条件下的成像公式．