挠性胶管的阻尼减振机理初探

建立了挠性胶管阻尼耗能的简化模型。以此为基础分析了挠性胶管的阻尼耗能的一般规律,并得出了一些新的结论。     

Trace elements in particles of motor vehicle exhaust in Shanghai

A nuclear microprobe with high spatial resolution and high analytical sensitivity was applied to analyze trace elements,especially lead,in vehicle exhaust of Shanghai city.The result shows that the chemical composition and its corresponding x-ray relative intensity are different among different vehicle exhausts.There are many kinds of metal elements in particles of vehicle exhaust.most are harmful to people,such as Ti,Cr,Mn,Pb,etc.We found that the lead concentration was 6820μg/g and the bromine concentration was 5300μg/g in the exhaust from Santana using leaded gasoline(SULG).which is higher than any other kinds of vehicle exhausts.We have also detected the minimum lead in the particles of unleaded gasoline and its content varies from one to another.Its mean concentration was 450μg/g and the highest reached 6210μg/g.The unleaded gasoline‘s Pb existed in the whole particle while the leaded gasoline‘s enriched in the surface of the particle and was more harmful to the human beings.     

Microscopic and Macroscopic Growth Rates of Fatigue Cracks in Steels and Alloys under the Influence of Crack Closure

On the basis of the experimental data, we show that the difference between the macroscopic and microscopic fatigue crack growth rates in the second section of the kinetic diagram of fatigue fracture is caused by the effect of crack closure within the limits of its existence. We establish the relationships between the macroscopic and microscopic fatigue crack growth rates and the structure of the material in the second section of the diagram for various values of the load ratio with regard for the effect of crack closure and propose a procedure of examination of the fracture processes in structural materials based on the analysis of microscopic and macroscopic fatigue crack growth rates.     

黄河黑山峡河段大柳树水库比小观音水库原始库容多40亿m3的作用

一级开发大柳树高坝原始库容比二级开发小观音高坝多 4 0亿m3 ,库容大带来的好处体现在 5～ 7月可多向下游增供水量 ,缓解下游河道断流 ;延长泄放清水时间 ;增加发电效益 ;满足宁蒙河段防凌要求 ;增加汛期集中泄水 ,减缓下游河道淤积萎缩 ;满足南水北调西线工程水量调节要求等。为了更好优化配置黄河水资源 ,从全局和长远利益考虑 ,应采用一级开发方案 ,修建大柳树高坝大库     

单轴传动滚切式双边剪薄钢板剪后“错牙”及“飞边”的原因分析与对策

针对单轴传动滚切式双边剪生产过程中出现的薄钢板经双边剪剪后出现“错牙”及“飞边”的问题,从多个方面入手对薄钢板出现“错牙”及“飞边”的原因进行了分析对比,提出了相应的解决方案,对今后滚切式双边剪的设计、制造及安装调试有借鉴和参考价值。     

I/OIMAGESYSTEM微波中继应用

微波中继的应用非常广泛 ,目前在二维、三维施工中跨越障碍物时 ,一般都使用微波中继站来传输命令和数据。文章就微波中继及I/OIMAGESYSTEM“蛇形排列”先进功能的实际应用进行了详细的阐述 ,同时提出了使用微波中继站应注意的问题。     

标准物质在分析测试中的重要地位及发展前景

标准物质在分析测试领域中无论在定值，方法的研究，误差确定等方面都有着重要地位。标准物质的质量保证及正确使用也应引起我们重视。随着科学技术迅速发展标准物质有着广阔发展前景。     

河道治理工程水土保持设计

河道治理工程的实施会对工程区域内的自然生态环境和水土保持带来负面影响。以独流减河左堤治理工程为例 ,分析工程建设中可能造成的水土流失影响 ,从工程和生物两方面提出水土保持的防治措施 ,并对其投资进行了初步估算。     

长距离油、气、水混输管道内壁流动腐蚀的研究进展

就近几十年来，多相流管线的流动腐蚀（CO2腐蚀，H2S腐蚀，腐蚀/冲蚀协同作用），腐蚀/冲蚀数学模型和设计准则，腐蚀检测，腐蚀防护与控制技术等方面的研究进展进行了综述。指出了当前研究中所存在的一些问题，就多相流的研究方向提出了相应的建议。     

关于化粪池几个问题的探讨

探讨化粪池在设计布置及使用管理中应注意的几个问题，以充分发挥化粪池在保护环境，减轻污染方面的作用。