一种含双络合剂的三价铬镀液研究

本文作者研究了以硫氰酸根和甘氨酸为络合剂的三价铬镀液,得到了光亮和均匀的镀层,并讨论了其最适宜的工艺条件和沉积机理.     

指定瞬时几何和运动参量的机构综合

本文提出一种新的解决指定瞬时几何和运动参量机构综合问题的方法,可用于指定动点轨迹的曲率、曲率变化率以及动平面和动点直至三阶运动参量的综合问题。     

高铬铸铁的热处理与二次硬化

利用扫描电镜分析和机械性能测试对15-2-1型高铬铸铁的二次硬化效应进行了研究,并结合合金耐磨性分析探讨了二次硬化效应在高铬铸铁锚喷衬板中的作用.     

Insights into acylphosphatase structure and catalytic mechanism

Acylphosphatase is one of the smallest enzymes known (about 98 amino acid residues). It is present in organs and tissues of vertebrate species as two isoenzymes sharing over 55% of sequence homology; these appear highly conserved in differing species. The two isoenzymes can be involved in a number of physiological processes, though their effective biological function is not still certain. The solution and crystal structures of different isoenzymes are known, revealing a close packed protein with a fold similar to that shown by other phosphate-bind ing proteins. The structural data, together with an extended site-directed mutagenesis investigation, led to the identification of the residues involved in enzyme catalysis. However, it appears unlikely that these residues are able to perform the full catalytic cycle: a substrate-assisted catalytic mechanism has therefore been proposed, in which the phosphate moiety of the substrate could act as a nucleophile activating the catalytic water molecule. Received 12 November 1996; accepted 27 November 1996     

新加坡图书馆员的长效培训机制探讨

新加坡极其重视教育发展,其图书馆是支撑其国家知识经济迅猛发展的重要因素,是促成其国民通过终身学习提高全面素质的主导力量。介绍了新加坡图书馆员的长效培训机制。     

一种基于8031单片机的瞬时测速方法

对高速冲击头运动参数的测试问题进行了研究，提出一种基于８０３１ 单片机的瞬时测速方法，可以精确测量出高速冲击头的瞬时速度，并可应用于其它类似的测速问题中。     

阻塞性黄疸血流动力学的变化

采用彩色多普勒超声对３０例正常人（Ａ组）和３６例阻塞性黄疸患者（Ｂ组）的门静脉，肝、脾、肾动脉血流动力学进行研究，结果表明：①阻塞性黄疸病人门脉血流速度低于正常人（Ｐ＜００５）；②肝、脾、肾动脉阻力指数阻塞性黄疸病人较正常人明显增加（Ｐ＜００１），而门静脉血流量仍在正常范围。进一步证明阻塞性黄疸血流动力学的变化对人体病理生理所造成的影响。     

Study on Surface Optimization by Ion Beams

Preliminary tribo-mechanical properties of IBED filmsof GCr15 bearing steels have been studied in this paperalong with the comparison between IBED films and PVDfilms as well as non-implanted surface in wear resis-tance,micro-hardness,friction and surface morpholo-gy.Experiments gave a consistent picture and statedclearly that TIN films can really improve the tribo-me-chanical properties of materials and have practical usesin a certain sense.However,further theoretical and ex-perimental studies must be performed in respect thatthere are some defects on IBED films.     

铆钉枪窝头热处理新工艺

用45#钢制成的铆钉枪窝头，选用临界点淬火工艺细化晶粒、选用多冲抗力峰值对应的温度回火及快冷工艺，使窝头的使用寿命提高了近百倍，热处理新工艺节能约20％。     

涡旋压缩机自调背压机构压力的优化分析

系统地分析了涡旋压缩机自调背压机构的工作原理和主要性能，通过推导摩擦损失功率和泄漏损失功率的计算式，建立自调背压机构压力优化分析模型，并给出可应用该模型进行背压求解的方法．