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

ＨｙｄｒｏｌｙｔｉｃｄｙｎａｍｉｃｓｏｆｐｅｓｔｉｃｉｄｅＮ＇－（２，４－ｄｉｍｅｔｈｙｌｐｈｅｎｙｌ）－Ｎ－ｍｅｔｈｙｌｆｏｒｍａｍｉｄｉｎｅｉｎａｑｕａｔｉｃｓｏｌｕｔｉｏｎ￥ＭｏＨａｎｈｏｎｇ；ＹａｎｇＫｅｗｕ；ＡｎＦｅｎｇｃｈｕｎ；ＬｉｕＹｅ...     

Management Options to Conserve and Sequester Carbon in the Agricultural Sector of the Former Soviet Union

Several management practices are available to conserve and sequester C in the agricultural sector of the former Soviet Union (FSU). The highest rate of C accumulation would result from the implementation of a no-till management option which will only continue during the first ten years until new C equilibrium is reached. Agroforestry management options provide a longer period for C accumulation, but at a lower rate. It is possible that the longest period of C conservation may be achieved by increasing the area under perennial grasses in the crop rotation. During the first decade of implementation of the management practices, the amount of C conserved or sequestered would be approximately equal to the current rate of net C sequestration in FSU forest sector. At present, agricultural soils and vegetation of the FSU store approximately 120 Pg C; the accumulation of soil organic matter is 0.032 Pg C yr^-1. The annual C loss in the FSU agricultural sector was estimated at 0.21 Pg C yr^-1.     

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．     

Buchbesprechungen

The Science of Nature -     

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.