变速器壳体低周疲劳优化设计

目的 分析变速器壳体驻车耐久试验的失效根本原因,对变速器壳体进行低周疲劳优化设计.方法 首先排查壳体的化学成分、铸造质量,排除材料和工艺引起失效问题的可能性,然后通过有限元方法分析驻车轴孔的最大拉应变、驻车工况壳体变形、轴孔接触区域.根据局部应变分布特征,提出驻车轴修形的优化方案,并且根据壳体材料的低周疲劳参数,确定Coffin-Manson模型,并根据该模型预测壳体驻车轴孔优化前后的疲劳寿命.结果 驻车轴孔的最大拉应变高达0.95％,确定应变过大是导致壳体失效的根本原因.驻车轴度修形的优化方案将最大拉应变降低到0.40％,塑性应变占比由42％降低到5％,疲劳寿命的预测值由原来的175次提高到7980次,满足试验循环次数1000次的要求,最终优化物理样机通过了驻车耐久试验验证.结论 使用的Coffin-Manson模型参数能准确地预测变速器壳体的低周疲劳寿命,驻车轴小角度修形优化方案能够有效解决局部应变过大的失效问题,具有一定的工程参考意义.     

溧阳市国家级生态示范区建设工作初探

综述了溧阳市创建国家级生态示范区的背景、依据、基础条件、创建的目标和技术路线，介绍了示范区建设的内容和具有特点的生态经济发展模式。     

管式反应器石灰雾液脱硫的数学模拟

建立的一维管式反应器雾液脱硫模型是对蒸发和吸收过程的耦合，以膜理论为基础的吸收机理同时考虑了含硫组分的离解、扩散、反应和固体颗粒的溶解。参数敏感性分析表明，对系统脱硫率影响最显的是出口干湿球温差，石灰颗粒粒度和入口ＳＯ２浓度、传质过程的分析表明，反应开始阶段液膜扩散和固体溶解阻力均存在，而气膜扩散在整个反应过程中都起着重要作用。     

城市大气污染物浓度预测模糊识别理论与模型

根据大气污染物的浓度具有模糊性且与多种指标相关的特点，提出对其进行预测的模糊识别理论与模型，并以二氧化硫为例，由２５个预测点大气中ＳＯ２浓度和相关指标的实测资料，利用上述理论与模型得出最优模糊预测参数，并对其它５个观测点的ＳＯ２浓度进行了预测检验。     

Study of prediction for groundwater contamination in wastewater land treatment system

This paper uses a prediction model of groundwater pollution based on the experiments in the laboratory and in field .The model, which was tested and calibrated by the field observated data ,satisfactorily simulated the field conditions in land treatment system of wastewater . Particularly , the model can provide the reliable pollution prediction of heavy metals , organisms and nitrogen . The model was used to predict the groundwater pollution caused by the land treatment system in the region of North China . The calibration of the model showed that correlation coefficients between the tested and predictive data of Cr6+. As3+, organism and NH4+ could reach 0.990, which proved that the model possessed the realistic instructive significance for design and use of wastewater land treatment systems .     

Developing Canada's National Forest Carbon Monitoring, Accounting and Reporting System to Meet the Reporting Requirements of the Kyoto Protocol

The rate of carbon accumulation in the atmosphere can be reduced by decreasing emissions from the burning of fossil fuels and by increasing the net uptake (or reducing the net loss) of carbon in terrestrial (and aquatic) ecosystems. The Kyoto Protocol addresses both the release and uptake of carbon. Canada is developing a National Forest Carbon Monitoring, Accounting and Reporting System in support of its international obligations to report greenhouse gas sources and sinks. This system employs forest-inventory data, growth and yield information, and statistics on natural disturbances, management actions and land-use change to estimate forest carbon stocks, changes in carbon stocks, and emissions of non-CO₂ greenhouse gases. A key component of the system is the Carbon Budget Model of the Canadian Forest Sector (CBM-CFS). The model is undergoing extensive revisions to enable analyses at four spatial scales (national, provincial, forest management unit and stand) and in annual time steps. The model and the supporting databases can be used to assess carbon-stock changes between 1990 and the present, and to predict future carbon-stock changes based on scenarios of future disturbance rates and management actions.     

本溪市区环境空气质量现状及变化趋势

对本溪市的环境空气质量进行了监测分析，结果表明：本溪市环境空气中TSP超过国家环境空气质量二级标准，SO2、NOx、CO、降尘均符合二级标准。其中TSP、SO2、CO、降尘呈下降趋势，NOx变化不明显。     

课堂教学案例开发的思考和实践

本文通过对教学案例涵义及类型进行分析,提出教学案例开发思路与方法,说明案例开发在培养人才中的作用和意义。     

谈双鸭山市气象特征及地形特征对空气质量的影响

双鸭山市采暖期污染较重是因为采暖期燃煤量大、低矮分散的面源多的缘故,同时气象因素及地形特征对空气质量的影响也起着相当大的作用,采用2005年空气质量监测数据,进行双鸭山市气象特征及地形特征对空气质量影响分析,得出空气较稳定的取暖期和具有山风、谷风、局地环流的地形特征是形成双鸭山市空气污染的主要原因之一,并针对地形特征及气象特征对双鸭山市空气质量的影响提出空气污染治理措施.     

沈阳市“十一五”期间的空气污染防治

根据沈阳市环境空气面临的问题,确定“十一五”期间空气环境质量保护目标、指标,提出改善空气环境质量的对策措施,保证沈阳市大气环境质量的持续改善。