华盛顿肯尼迪表演艺术中心

1963年10月,当时的美国总统约翰·肯尼迪在一次集会上说:“世界各国都有宏伟美观的表演艺术中心,而作为大国首都的华盛顿却缺少这样的设施。”他决定要在美国首都建造一座表演艺术殿堂,当时定名为国家文化中心。几个星期后的11月22日,肯尼迪在达拉斯市遇刺身亡。1971年,建筑物落成,冠以已故     

100LFD－32型稀硫酸泵

开发研制１００ＬＦＢ—３２稀酸净化循环泵。其衬里所选之聚全氟乙丙烯和聚四氟乙烯的复合物，较ＰＶＣ、ＰＥ和ＡＢＳ性能皆优良；结构设计形式避免了酸的泄漏和下轴承磨损。泵效率＞５０％。工业性试验，连续运行３０００小时以上。     

糖尿病人的夏季食疗

夏季是糖尿病患者治疗的最佳时机,由于体内血糖的变化与季节的关系非常密切,冬天的血糖要比春秋高,而夏天是一年中血糖最低的季节。故此时糖尿病患者若在常规治疗的基础上配合饱含疗法,则能收到事半功倍的效果。     

Influence of melt superheat on breakup process of close-coupled gas atomization

In close-coupled gas atomization（CCGA）, the influences of melt superheat on breakup process are fundamental to obtain desired or finer powder. Based on a series of Cu atomization experiment under different superheating conditions, the influences of melt superheat on breakup process were studied. Experimental results indicate that as the melt superheat is increased to 150, 200, 250 and 300 K, the mean particle size （D50） decreases consequently to 34.9, 32.3, 30.9 and 19.7 μm. Theoretical analysis reveals that the primary breakup and secondary breakup processes are close coupled, and the melt superheat radically influences the melt properties, and plays a crucial role on governing the filming process of primary breakup and the atomization modes of secondary breakup. There exists a strong nonlinear decrease of contact angle of melt to nozzle orifice wall when the superheat is increased fi＇om 250 K to 300 K, leading to a marked fall of the film thickness formed in primary breakup, and D50 of copper powders is therefore sharply reduced. However, the log-normal distribution feature of particle size has not been substantially improved.     

水文自动测报系统防雷的探讨

水文自动测报系统若配备有线／无线（GSM，GPRS）双通道，可提高系统的可靠性，保证系统的畅通。然而，有线组网方式最致命弱点是防雷能力差，针对防雷问题，在实践中探讨其有效途径，论述接地装置的设计、安装中应注意的几个问题，并介绍在实践中电话线防雷从一级防护发展到三级防护，提高防雷的效果，有待在实践中，再认识，再提高。