Visual pigment: G-protein-coupled receptor for light signals

The visual pigment present in photoreceptor cells is a prototypical G-protein-coupled receptor (GPCR) that receives a light signal from the outer environment using a light-absorbing chromophore, 11-cis-retinal. Through cis-trans isomerization of the chromophore, light energy is transduced into chemical free energy, which is in turn utilized for conformational changes in the protein to activate the retinal G-protein. In combination with site-directed mutagenesis, various spectroscopic and biochemical studies identified functional residues responsible for chromophore binding, color regulation, intramolecular signal transduction and G-protein coupling. Extensive studies reveal that these residues are localized into specific domains of visual pigments, suggesting a highly manipulated molecular architecture in visual pigments. In addition to the recent findings on dysfunctional mutations in patients with retinitis pigmentosa or congenital night blindness, the mechanism of intramolecular signal transduction in visual pigments and their evolutionary relationship are discussed. Received 20 July 1998; received after revision 9 September 1998; accepted 23 September 1998     

机械加工零件倒角与倒圆的简便取值法

本文试探对倒圆与倒角的标准数据(或推荐值),进行数理统计,从中建立起变量之间的数学表达式(即经验公式),以求在设计制图中简便取值,方便作图提高工作效率.即使对标准中未给出的数据,还可以进行科学地预测或估算.     

数控设备通信连接——现场信息管理系统的研究

针对江西工业职业技术学院原数控设备利用效率低的现状,进行了一系列的研究,利用现代的通信管理技术,实现数控机床的共享管理,使有限的数控设备与众多的计算机有机地连接起来,达到数控教学改革的目的.     

基于视觉的汽车覆盖件塑性主应变测定

基于视觉技术采用方形网格法进行变形区域塑性主应变分布测量.分析了其原理、特点以及根据节点位移计算塑性主应变的相关理论和方法.     

计算机主动视觉理论研究

在David Marr提出视觉计算理论之后，计算机视觉的研究取得了很大进步，但Marr理论也遇到了很多困难．本文介绍了主动视觉的基本思想和已经研制成功的主动视觉系统，分析了当前主动视觉研究领域面临的问题，针对这些问题，作者提出了一些建议．     

数控机床坐标系比较与应用研究

本文介绍了在数控机床使用中的几种坐标系,对它们的相互关系及建立坐标系方法进行了比较和研究,并结合不同数控系统及生产实际,具体阐述了在加工中建立工件坐标系方法及其注意事项。     

C6240F车床动态特性研究

本文根据机床的振动理论，对Ｃ６２４０Ｆ型车床进行了动态特性实验研究，通过对该机床的激振 试验，论证了机床的各阶固有频率，测定并论述了机床各振型，分析了该机床的薄弱环节，对机 床提出了改进设计建议。     

糖尿病性白内障摘除和人工晶体植入疗效观察

报告３４例糖尿病性白内障行白内障囊外摘除联合人工晶体植入术，结果表明，将糖尿病人血糖控制稳定在一定水平，同时注意检查和处理并发症，进行眼科手术是比较安全的，能达到预期的复明效果。     

思想的幻象与艺术的真实——《幻象》在叶芝诗歌创作中的地位初探

<幻象>是叶芝一部非常重要的散文著作.然而它对叶芝诗歌创作的价值一直没有引起人们足够的重视.本文在对<幻象>追根溯源和阐释的基础上,揭示它对叶芝诗歌创作的诸多影响,从而肯定<幻象>在叶芝诗歌创作中的积极作用.旨在从一个新的角度认识叶芝.     

Multi-objective dynamic detection of seeds based on machine vision

An approach to inspecting massive numbers of moving seeds was studied based on the techniques of dynamic inspection and machine vision. A progressive scanning CCD camera with external trigger function was used for real-time capture of dynamic images of seeds. The methods based on R channel of RGB (Red, Green and Blue) and region-dependent segmentation were adopted to reduce the data size of image processing and improve the efficiency of seeds inspection. All the seeds were sorted into four grades according to their morphological characteristics, such as surface area, perimeter, major axis, minor axis, circularity and eccentricity. The detection experiments indicated that the eligible ratio of the classifications was about 81.90% by this real-time inspection system.