期刊文献+
共找到2篇文章
< 1 >
每页显示 20 50 100
强度m的对称正交表构造的新结果
1
作者 赵芳 马玉磊 +1 位作者 董乐 杜蛟 《河南师范大学学报(自然科学版)》 CAS 北大核心 2016年第4期34-38,共5页
对于给定的一个对称正交表K1,通过对正交表的行进行分析,提出了一个构造正交分划{K1,K2,…,Kqk}的方法,得到的这个正交分划可以直接用于高强度对称正交表的构造,在一定条件下还讨论了正交分划中正交表的强度.在此基础上,对已有的高强度... 对于给定的一个对称正交表K1,通过对正交表的行进行分析,提出了一个构造正交分划{K1,K2,…,Kqk}的方法,得到的这个正交分划可以直接用于高强度对称正交表的构造,在一定条件下还讨论了正交分划中正交表的强度.在此基础上,对已有的高强度对称正交表的递归构造方法做了进一步推广,给出了一个新的对称正交表的构造方法.最后,还给出了一些实例. 展开更多
关键词 对称正交表 递归构造 Qn的正交分划 平衡性
下载PDF
Mass balance-based regression modeling of Cd and Zn accumulation in urban soils of Beijing 被引量:7
2
作者 Chi Peng Meie Wang +2 位作者 Weiping Chen Andrew C.Chang John C.Crittenden 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2017年第3期99-106,共8页
Accumulation of heavy metals in urban soil can pose adverse impacts on public health and terrestrial ecosystems. We developed a mass balance-based regression model to simulate the heavy metal accumulation in urban soi... Accumulation of heavy metals in urban soil can pose adverse impacts on public health and terrestrial ecosystems. We developed a mass balance-based regression model to simulate the heavy metal accumulation in urban soils as a function of time and to explore connections between metal concentration and urbanization processes. Concentrations of Cd and Zn in 68 residential soil samples in the urban area of Beijing were used. The background concentrations, the loss rates and the input fluxes of Cd and Zn in urban soils of Beijing during the last three decades were estimated using a regression of the time series of accumulations of the metals. Based on the regression estimates, we simulated the general trends of Cd and Zn accumulation in the soils from 1978 to 2078. The concentrations of Cd and Zn in urban soil generally increased with the population growth, vehicle use and coal consumption. The mean concentrations of Cd and Zn in urban soil of Beijing would increase by 3 fold over the next 70 years for the current development scenario. The mass balance-based regression approach, which is able to reconstruct the history data of urban soil pollution, provides fundamental information for urban planning and environmental management. 展开更多
关键词 Heavy metalsMass balance modelUrbanizationTrading space for timeRisk predictionSoil pollution
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部