排序方式: 共有85条查询结果,搜索用时 15 毫秒
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该文以德黑兰北部高速公路项目的工程实践为基础,总结了中国公路隧道围岩分级法和挪威Q法及南非RMR法对应关系,为隧道围岩分级的中外技术交流建立共同的平台。 相似文献
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Productive efficiency of public and private solid waste logistics and its implications for waste management policy 总被引:1,自引:0,他引:1
This paper measures the productive efficiency of municipal solid waste (MSW) logistics by applying data envelopment analysis (DEA) to cross-sectional data of prefectures in Japan. Either through public operations or by outsourcing to private waste collection operators, prefectural governments possess the fundamental authority over waste processing operations in Japan. Therefore, we estimate a multi-input multi-output production efficiency at the prefectural level via DEA, employing several different model settings. Our data classify the MSW into household solid waste (HSW) and business solid waste (BSW) collected by both private and public operators as separate outputs, while the numbers of trucks and workers used by private and public operators are used as inputs. The results consistently show that geographical characteristics, such as the number of inhabited remote islands, are relatively more dominant factors for determining inefficiency. While the implication that a minimum efficient scale is not achieved in these small islands is in line with the literature suggesting that waste logistics has increasing returns at the municipal level, our results indicate that waste collection efficiency in Japan is well described by CRS technology at the prefectural level. The results also show that prefectures with higher private-sector participation, measured in terms of HSW collection, are more efficient, whereas a higher private–labor ratio negatively affects efficiency. We also provide evidence that prefectures with inefficient MSW logistics have a higher tendency of suffering from the illegal dumping of industrial waste. 相似文献
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Q345R钢是普通低合金高强度钢,广泛的用于压力容器制造行业。其S、P含量控制较严,焊接性较好,但是由于含有一定量的合金元素,淬硬、冷裂倾向都比低碳钢大一些。通过船用氮气储存罐的筒体和封头环焊缝的焊接,分析了Q345R钢的化学成分和机械性能,通过选用合理的焊接材料、坡口形式、焊接方法、焊接工艺来保证储存罐的焊缝质量。 相似文献
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Yan Lia Xiao-Rong Liut Xiao-Hui Ning Can-Can Hnang Jian-Bin Zheng Jun-cai Zhang 《西安交通大学学报(英文版)》2011,1(4)
An electrochemical sensor incorporating a signal enhancement for the determination of lead (II) ions (Pb2+) was designed on the basis of the thrombin-binding aptamer (TBA) as a molecular recog- nition ... 相似文献
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针对现有Xen虚拟机性能监视工具的不足,设计了一个专用的Xen虚拟机CPU性能监视工具xcPUMon(XenCPUMonitor),对Xen虚拟机上的CPU的各项性能参数都进行监测和记录,包括物理CPU和虚拟CPU。该文简要介绍了XCPUMon的组成,详细分析了CPU利用率评估算法。实验结果表明:XCPUMon能准确、全面的获取各个Domain的CPU信息。 相似文献
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