The vertical distribution and migration of Cu,Zn,Pb,and Cd in two forest soil profiles near an industrial emission source were investigated using a high resolution sampling method together with reference element Ti.On...The vertical distribution and migration of Cu,Zn,Pb,and Cd in two forest soil profiles near an industrial emission source were investigated using a high resolution sampling method together with reference element Ti.One-meter soil profile was sectioned horizontally at 2 cm intervals in the first 40 cm,5 cm intervals in the next 40 cm,and 10 cm intervals in the last 20 cm.The migration distance and rate of heavy metals in the soil profiles were calculated according to their relative concentrations in the profiles,as calibrated by the reference element Ti.The enrichment of heavy metals appeared in the uppermost layer of the forest soil,and the soil heavy metal concentrations decreased down the profile until reaching their background values.The calculated average migration rates of Cd,Cu,Pb,and Zn were 0.70,0.33,0.37,and 0.76 cm year-1,respectively,which were comparable to other methods.A simulation model was proposed,which could well describe the distribution of Cu,Zn,Pb,and Cd in natural forest soils.展开更多
针对传统粗粒度并行遗传算法容易早熟并且收敛速度较慢的不足,提出一种新的并行遗传算法。新算法采用了一种基于相对平均适应度的动态调整迁移率的方法及时增加了其它岛屿到相对平均适应度较高的岛屿的迁移率,从而有效的增加了种群的多...针对传统粗粒度并行遗传算法容易早熟并且收敛速度较慢的不足,提出一种新的并行遗传算法。新算法采用了一种基于相对平均适应度的动态调整迁移率的方法及时增加了其它岛屿到相对平均适应度较高的岛屿的迁移率,从而有效的增加了种群的多样性,抑制了早熟现象,提高了最优解的质量。同时,提出了一种存活期的计算方法,对直接迁入每个岛屿中的个体计算存活期并淘汰年龄超过存活期的个体,控制了岛屿的规模,增强了算法的收敛性能,加快了收敛速度。将提出的改进算法用Muth and Thompson基准问题测试,验证了该算法的有效性。展开更多
基金the National Natural Science Foundation of China (No40625001)the Knowledge Innovation Pro-gram of the Chinese Academy of Sciences (NoKZCX2-YW-409)the Jiangsu Provincial Natural Science Foundation of China (NoBK2004167)
文摘The vertical distribution and migration of Cu,Zn,Pb,and Cd in two forest soil profiles near an industrial emission source were investigated using a high resolution sampling method together with reference element Ti.One-meter soil profile was sectioned horizontally at 2 cm intervals in the first 40 cm,5 cm intervals in the next 40 cm,and 10 cm intervals in the last 20 cm.The migration distance and rate of heavy metals in the soil profiles were calculated according to their relative concentrations in the profiles,as calibrated by the reference element Ti.The enrichment of heavy metals appeared in the uppermost layer of the forest soil,and the soil heavy metal concentrations decreased down the profile until reaching their background values.The calculated average migration rates of Cd,Cu,Pb,and Zn were 0.70,0.33,0.37,and 0.76 cm year-1,respectively,which were comparable to other methods.A simulation model was proposed,which could well describe the distribution of Cu,Zn,Pb,and Cd in natural forest soils.
文摘针对传统粗粒度并行遗传算法容易早熟并且收敛速度较慢的不足,提出一种新的并行遗传算法。新算法采用了一种基于相对平均适应度的动态调整迁移率的方法及时增加了其它岛屿到相对平均适应度较高的岛屿的迁移率,从而有效的增加了种群的多样性,抑制了早熟现象,提高了最优解的质量。同时,提出了一种存活期的计算方法,对直接迁入每个岛屿中的个体计算存活期并淘汰年龄超过存活期的个体,控制了岛屿的规模,增强了算法的收敛性能,加快了收敛速度。将提出的改进算法用Muth and Thompson基准问题测试,验证了该算法的有效性。
