Acetylcholine receptor at neuromuscular junctions by EM autoradiography using mask analysis and linear sources

Several methods of analyzing EM autoradiograms are now available. Two such procedures, the grain density distribution (or histogram) method and the mask method use the resolution of the EM autoradiographic technique to generate grain distributions expected from postulated sources, and compare these with the observed grains in the autoradiograms. These two methods are here compared in the analysis of label on linear sources: the distribution of labeled acetylcholine receptor (AChR) down the postjunctional folds of lizard and frog neuromuscular junctions. The receptors were labeled with I-25-α-bungarotoxin and the autoradiograms coated with the high resolution Kodak emulsion 129–01. We found that both methods gave similar results in confirming that the bulk of the AChR is concentrated on the thickened region of the membrane at the top ∼2000 A of the junctional folds, and that there may be a gradient of receptor concentration down the folds. The grain density distribution method is simpler, but does not lend itself easily to quantifying the extent of deviation from simple models. Although computer graphics is not necessary for either method, its use allows the expected grains from linear sources to be generated quickly, making the mask analysis a feasible routine method for assigning the extent of label in different membrane regions.     

浅谈一次性防护口罩的研制

介绍了纺织工业非织造布技术开发中心研制的一次性非织造布防护口罩产品的材料构成及性能特点。说明了其与普通口罩相比具有屏蔽性强、防止细菌交叉感染等功能，能够达到一定的防护技术要求。     

The impact of new hardware on OCR designs

This paper describes the opportunities available to radically improve the performance cost ratio of OCR machines by taking advantage of new hardware which is either here, or can be made available by inter industry cooperation. Major discussions center around:(1) The page width self-scanned-array (1872 photodiodes) which can be used to greatly reduce the number of mechanical operations needed to scan a multi-line document: (2) The much reduced cost of semiconductor memory (particularly the charge coupled devices) which allows the use of memory to eliminate double scanning as well as other awkward and embarrassing operations: (3) A proposal for an LSI correlator which can provide substantial gains in all performance and cost categories, as well as providing prospects for the modest application of developments in learning theory. The leadership to provide such a correlator may have to spring from the OCR industry, including agreement on certain standards.     

同步辐射X射线光刻掩模镀金工艺的研究

介绍了利用北京正负对撞机(BEPC)同步辐射X射线光刻装置,进行LIGA工艺技术深结构光刻实验研究,详细论述了X射线光刻使用的掩模制备过程及掩模镀金工艺,在国内最早曝光出直径为400μm、厚为27～45μm的三维立体齿轮胶图形。     

"建构学的哲学"解读

文章从四个方面解读了席沃扎博士的论文“建构学的哲学”:作者的学术背景和相关著述;建构学的兴起;德国建筑理论中的“建构学”;从建筑的“现代性”来分析现代建筑时期的建构学、当代建构学和作者提出的“镜头景观”。     

50nm X射线光刻掩模制备关键技术

X射线光刻(XRL)采用约1nm波长的X射线,是一种接近式光刻。就光刻工艺性能而言,XRL能同时实现高分辨率、大焦深、大像场等,是其他光刻手段难以比拟的。由于不需要辅助工艺,因而工艺成本很低。掩模制造技术是XRL开发中最为困难的部分。本文介绍了适用于50nm XRL的掩模制备的关键技术。     

掩模清洗机加热系统控制及故障排除

在集成电路掩模(Mask)生产过程中,清洗机是关系到掩模制板质量的一个重要设备。因为掩模工艺需要使用大量的化学溶剂,并需配置多个加热控制系统,致使清洗设备成为一个故障率高、易损件损坏多的设备。介绍清洗机加热系统控制原理,其中包括Genius I/O、手持监控器、PID控制、电流监控器、安全电路和加热脉冲。对其控制原理及电路进行了解析,最后通过应用实例给出了故障的排除方法。     

JB系列光刻机的原理及维修技术

简述了 JB系列光刻机的基本工作原理以及常见故障的分析和维修 ,同时给出了设备的日常维护保养措施。     

BRIGADIER JOHN TILTMAN: ONE OF BRITAIN'S FINEST CRYPTOLOGISTS

Biography of Brigadier John Tiltman, who worked as a cryptologist for the British and American governments from 1920 to 1980.     

A high efficiency single molecule localisation algorithm with sub-pixel resolution based on fluorescence images

We introduce a technique of fast single molecule localisation including image de-noising and Gaussian mask sub-pixel refinement (IDGM) with the characteristics of simplicity, great computational efficiency as well as high accuracy and precision. The image de-noising corrects images suffering from background and shot noise, and the Gaussian mask is used to derive the centres of single molecules with sub-pixel resolution. We quantitatively evaluate the performance of IDGM compared to two-dimensional direct Gaussian fitting (2DDGF) on 1000 simulated images at variable signal-to-noise ratios (SNRs), where the single molecule diffraction spot is simulated as a point spread function distribution. It is shown that IDGM performs better than 2DDGF in terms of accuracy and precision for all tested SNRs. In addition, the execution time is shorted by one order of magnitude, making the IDGM algorithm suitable for localising single molecules especially for on-line or time-critical applications.