Hydrolytic dynamics of pesticide N''-(2,4-dimethylphenyl) -N-methylformamidine in aquatic solution

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应用GEM法对硫酸工业中重金属污染的研究

为查明硫酸工业中主要重金属的危害以及不同制酸工艺产生的危害差异，对辽宁省主要生产硫酸企业进行了调研，并应用ＭＥＧ法，对矿石原料中重金属的含量进行了数学模型分析．     

Web开发中使用数据库连结池技术

数据库连接池的基本思想就是为数据库连接建立一个"缓冲池".预先在缓冲池中放入一定数量的连接,当需要建立数据库连接时,只需从"缓冲池"中取出一个,使用完毕之后再放回去.我们可以通过设定连接池最大连接数来防止系统无尽的与数据库连接.更为重要的是我们可以通过连接池的管理机制监视数据库的连接数量、使用情况、为系统开发、测试及性能调整提供依据.     

The economics of climate change in agriculture

This paper presents a conceptual frameworkof the impact of climate change onagriculture. It assumes that climatechange will result in a fertilizationeffect and a shift of agro-ecologicalconditions away from the Equator towardsthe Poles. The agro-ecological shift islikely to reduce yield because of reducedacreage and the fertilization effect willincrease yield. The aggregate effectdepends on whichever of the two dominates. The overall effect of climate change may beless significant than its distributionaleffects and the results are consistentwith previous empirical studies. Theimpact of climate change depends on itspace. Faster changes in climate willresult in higher cost. The assessment ofthe cost has to consider that climatechange is a dynamic phenomenon that mayrequire continuous adjustment. Environmental regulation that emphasizesconservation may increase cost ofadjustment and environmental policiesshould emphasize adaptation andflexibility.