论技术规范与标准的关系

目前对技术规范与标准称技术标准,以免与日常说的一般标准相混淆)的关系有两种不同的理解。一种认为,技术标准是技术规范的组成部分;另一种则相反,认为技术规范是技术标准的组成部分。前者多见于日常论述规范的范畴,后者常见于标准化领域。     

Numerical model of on-road emission rates of diesel buses in Beijing

A total of 14 in-use diesel buses were selected to conduct emission measurement using a portable emissions measurement system(PEMS)in Beijing.Their instantaneous gaseous emission rates,particular matter(PM)emission rates and driving parameters were obtained.The influences of speed,acceleration and vehicle specific power(VSP)on emissions were analyzed.Based on the relationships between these driving parameters and emissions,24 driving bins defined by speed,acceleration and VSP were constructed with cluster analysis to group emission rates for Euro Ⅲ and Ⅳ buses,respectively.Then the emissions reductions from Euro Ⅲ to Euro Ⅳ diesel buses were analyzed.Lastly,on-road hot-stabilized emission rate model for diesel buses in Beijing was developed.Through the comparison of the model simulation emission rates with the measured emission rates,the modeled emission results were in good agreement with the measured emission results.In most of the cases,the differences were less than 12%.     

钢护筒参与桩身受力的构造处理和计算分析

以苏通大桥为例,介绍特大桥钢护筒参与桩身受力的构造处理和计算分析方法。     

标准作用试析

关于标准的作用已有不少著作、论文做过多方的论述,所论各有侧重。这里想从产品生产中所起的作用出发,对标准的作用做些探讨,以求从中得到一点启迪,供有兴者讨论研究或参考。 现代化工业生产基本上是这个模式:用自然界存在的物质或他人生产出的产品,做为自己生产中所用的原料、材料、燃料、元件、零件、部件,