薄壁厚内螺纹的冷挤压

薄壁厚内螺纹的冷挤压成形是道难题,通过采用有效的工艺措施,确保了产品质量,拓宽了内螺纹冷挤压成形的适用范围。     

建筑物尾流区气流与污染物扩散的数值计算

采用了细网格非静力能量闭合边界层模式和随机游动模拟方法建立了一套分析建筑物尾流流场和污染物扩散的数值模拟系统．作为应用研究的例子，在对某城市地下交通隧道排废气的风井塔尾流区流场和浓度场进行风洞流体物理实验的基础上，利用所建的模拟系统对风井塔尾流区气流和污染物扩散特征进行研究．结果表明，所建的模拟系统的模拟结果与风洞试验的结果吻合较好，对一些小尺度带有明显湍流不均匀性的流场和局地空气污染物散布的情况有较好的模拟效果和良好的应用前景．     

旋压变形数值模拟中局部加载卸载问题的处理

此文介绍了旋压加工数值模拟中遇到的局部加载卸载问题的处理方法,并对筒形件强力旋压过程进行了数值模拟,求得了变形区应力应变的分布,理论计算结果与变形实际和实测结果完全吻合.     

辛基酚的体内类雌激素活性评价

利用体内大鼠子宫增重试验检测辛基酚（OP）的类雌激素活性，并对其观测终点及影响因素进行了初步研究。结果显示，OP经大鼠体内染毒，可引起大鼠子宫湿重、子宫内皮细胞厚度、子宫腺数量明显增加，具有明显的类雌激素活性。三条染毒途径检测敏感度腹腔染毒＞经皮下染毒＞经灌胃染毒。     

约束求解的数据模型及算法

此文针对参数化造型系统中约束方程组的求解问题,深入分析了匹配求解的核心思想,提出了一种简单实用的约束网络建模方法,并且围绕该数据模型介绍了与其相关的算法.     

城郊道路交通污染个例分析

为建立和研究适合地面道路的宽路幅、高等级、支路多等特点的大城市城郊道路交通大气污染扩散模式,选取了受环境外来源影响较小的上海市沪青平公路的徐泾段,作交通大气污染实测和相关气象因子项目的观测。在获得详细实测结果的基础上,以NOx为例分析了大气稳定度、风向、风速、交通量对城郊地面道路交通污染扩散的影响。     

Effects of atmospheric gases on terrestrial plants and critical levels of air pollution

An integrated approach was developed to determine the critical levels of air pollution for ecological standard setting based on the unified index of biological response, by taking into account the effects of all pollution components simultaneously. An empirical model of plant productivity was taken as the dose response model for gaseous pollutant effect on the productivity of trees and the annual productivity of plants was used as the above mentioned index. The CO2 increase in the lower atmosphere was considered to potentially increase plant productivity and NO2 was estimated as neutral while being dangerous for plants as a chemical precursor of ozone or as a source of acidification. The maximum permissible chronic O3 and SO2 levels for trees were estimated and it was found that O3 is much more phytotoxic, as compared to SO2 , with a rather narrow range of permissible levels (27-33 ppb) which complicates its monitoring and control.     

Environmental impact of China''''s village and township industry(1988-1992): a comparison with urban industry

１ＩｎｔｒｏｄｕｃｔｉｏｎＶｉｌａｇｅａｎｄｔｏｗｎｓｈｉｐｉｎｄｕｓｔｒｙ（ＶＴＩ）ｉｓｂｅｃｏｍｉｎｇａｖｅｒｙｉｍｐｏｒｔａｎｔｃｏｍｐｏｎｅｎｔｏｆＣｈｉｎａｓｅｃｏｎｏｍｙａｎｄｅｎｖｉｒｏｎｍｅｎｔ．Ｉｎ１９９２，ＶＴＩｐｒｏｄｕｃｅｄ...     

Microbial flocculant and its application in environmental protection

１ＩｎｔｒｏｄｕｃｔｉｏｎＡｌｏｔｏｆｖａｒｉｅｄｆｌｏｃｃｕｌａｎｔｓｈａｖｅｂｅｅｎｕｓｅｄｉｎｗａｓｔｅｗａｔｅｒｔｒｅａｔｍｅｎｔ，ｄｒｅｄｇｉｎｇｄｏｗｎｓｔｒｅａｍｐｒｏｃｅｓｓｉｎｇａｎｄｓｏｍｅｉｎｄｕｓｔｒｉａｌｆｉｅｌｄｉｎｃｌ...     

齿形零件的冷摆辗成形

介绍了摆辗成形工艺的基本原理,综述了齿形零件冷摆辗精密成形和摆动辗压设备研制的概况.指明用压力加工方法,特别是冷摆辗工艺.加工精密齿形可提高零件机械性能,节能节材.