Subjects: Geosciences >> Geography submitted time 2023-12-06 Cooperative journals: 《干旱区地理》
Abstract：随着城市扩张和工业化进程的加快，我国大型城市核心城区土壤已遭受不同程度的重金属污染。以乌鲁木齐市核心城区典型城市公园绿地和交通枢纽绿地为对象，系统探究土壤中6种重金属（Cd、Cr、Cu、Pb、Zn和Ni）的累积特征和生态风险。结果表明：（1） 交通枢纽绿地土壤重金属含量均高于城市公园绿地土壤。相较于乌鲁木齐市土壤背景值，城市公园绿地土壤重金属为轻度污染，而交通枢纽绿地土壤重金属为中度污染。（2） 不同行政区城市公园绿地土壤重金属综合污染指数为：头屯河区（2.85）>水磨沟区（2.13）>天山区（1.91）>新市区（1.85）>米东区（1.23），而交通枢纽绿地土壤重金属综合污染指数为：米东区（4.17）>沙依巴克区（3.24）>新市区（2.84）>水磨沟区（2.70）>头屯河区（2.50）>天山区（2.37）。（3） 不同行政区城市公园绿地土壤重金属的潜在生态风险指数为：水磨沟区（101.68）>头屯河区（98.83）>新市区（88.56）>天山区（73.43）>米东区（58.24），而交通枢纽绿地土壤重金属的潜在生态风险指数为：米东区（177.60）>水磨沟区（131.75）>沙依巴克区（120.25）>新市区（105.76）>头屯河区（105.63）>天山区（82.12）。城市公园绿地土壤综合污染指数和潜在生态风险指数最大的分别为头屯河区和水磨沟区，而城市交通枢纽绿地土壤的综合污染指数和潜在生态风险指数最大的均是米东区。（4） 在空间分布特征上，城市公园绿地土壤高值区总体上以岛状分布在中心城区，而交通枢纽绿地土壤除Ni外，高值区以岛状分布在米东区的西南部和沙依巴克区的东部。工业企业的显著集聚、密集的交通干线和较高的人口密度成为影响不同行政区内土壤重金属污染程度差异的主要因素。
Subjects: Other Disciplines >> Synthetic discipline submitted time 2023-03-28 Cooperative journals: 《中国科学院院刊》
Abstract： The problem of sandy desertification in Tibet is one of important regions of desertification research in China, the important progresses in the research on sandy desertification in Tibet in recent thirty years are concluded in the paper, such as finding out the status and characteristics of spatial and temporal change in recent years of sandy desertification in Tibet as well as its driving factors, establishing the theoretical system of sandy desertification in Tibet including the classification system of sandy desertification land and geological-historical evolutionary process of sandy desertification as well as the features of river valley aeolian landform in Tibet, building the combating strategy and control technical system of sandy desertification in Tibet with special plateau features. On the basic analysis of status and development trends as well as the control results of sandy desertification in Tibet, the future combating idea of sandy desertification in Tibet are forward given.
Subjects: Computer Science >> Integration Theory of Computer Science submitted time 2019-01-03 Cooperative journals: 《计算机应用研究》
Abstract： In the application scenario of edge computing, resource deployment and allocation are important issues. In order to address the load balancing needs in edge computing network, this paper propose a scheduling scheme based on centralized control. This scheme decides which nodes to deploy edge computing module firstly, then considering users’ data and requests, minimizes the average end-to-end delay of traffic through scheduling while meeting the load balancing constraints. The evaluation results indicate that the number of edge computing nodes and the load balancing level of computing and network resources may affect the average end-to-end delay of traffic. Selecting a small number of suitable nodes as edge computing nodes and making the load balancing level of computing and network resources appropriate can effectively reduce the average end-to-end delay.
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