需求势能理论在多级物流网络预选点中的应用

针对分销物流网络的特点,提出了基于服务时限的多级物流网络选址问题和选点思路,应用需求势能理论建立了多网点选址数学模型,并提出了详尽的求解方法和步骤。最后通过医药分销物流网络系统的实例分析,说明了该方法在网络选点过程中的模型化方法和求解步骤。     

Sectoral Energy- and Labour-Productivity Convergence

This paper empirically investigates the development of cross-country differences in energy- and labour productivity. The analysis is performed at a detailed sectoral level for 14 OECD countries, covering the period 1970–1997. A σ-convergence analysis reveals that the development over time of the cross-country variation in productivity performance differs across sectors as well as across different levels of aggregation. Both patterns of convergence as well as divergence are found. Cross-country variation of productivity levels is typically larger for energy than for labour. A β-convergence analysis provides support for the hypothesis that in most sectors lagging countries tend to catch up with technological leaders, in particular in terms of energy productivity. Moreover, the results show that convergence is conditional, meaning that productivity levels converge to country-specific steady states. Energy prices and wages are shown to positively affect energy- and labour-productivity growth, respectively. We also find evidence for the importance of economies of scale, whereas the investment share, openness and specialization play only a modest role in explaining cross-country variation in energy- and labour-productivity growth.      

Climate Change Taxes and Energy Efficiency in Japan

In 2003 Japan proposed a Climate Change Tax to reduce its CO₂ emissions to the level required by the Kyoto Protocol. If implemented, the tax would be levied on fossil fuel use and the revenue distributed to encourage the purchase of energy efficient equipment. Analysis using the MIT Emissions Prediction and Policy Analysis (EPPA) model shows that this policy is unlikely to bring Japan into compliance with its Kyoto target unless the subsidy encourages improvement in energy intensity well beyond Japan’s recent historical experience. Similar demand-management programs in the US, where there has been extensive experience, have not been nearly as effective as they would need to be to achieve energy efficiency goals of the proposal. The Tax proposal also calls for limits on international emission trading. We find that this limit substantially affects costs of compliance. The welfare loss with full emissions trading is 1/6 that when Japan meets its target though domestic actions only, the carbon price is lower, and there is a smaller loss of energy-intensive exports. Japan can achieve substantial savings from emissions trading even under cases where, for example, the full amount of the Russian allowance is not available in international markets.     

中国能源安全现状及其可持续发展

作为世界上第三大能源消费进口国,中国的能源安全问题和能源安全战略的实施是我国保持持续平稳发展所必须认真面对的重要课题和基本任务。本文从能源安全的基本内涵、发展历程、不同类型国家的能源安全战略对比分析以及中国能源安全现实的剖析,以发展的眼光分别在战略上和战术上提出了几大对策,从而使中国能源安全实现可持续发展。     

某拦河闸底流消能工消能防冲试验研究

通过物理模型试验,对某拦河闸底流消能工进行消能防冲试验,测试和分析不同开度下的水闸运行流态、流速分布及上下游水流衔接状况,研究成果可供工程设计参考。     

巢湖兆河分洪闸泄流特性试验研究

受周边地形条件及环境限制,巢湖兆河分洪闸与河道呈垂直布置,进流条件不利。针对分洪闸与河道垂直布置这一特征,分别对开敞式和涵洞式分洪闸进行了水工模型进口流态试验分析,结果表明涵洞式分洪闸进流流态优于开敞式分洪闸,能更好地保证各闸孔的均匀进流。针对涵洞式分洪闸方案,研究了分洪闸敞泄和控泄的泄流能力,指出敞泄状态下进口行近流速对流量计算影响明显,在水闸规划设计中,应计入行近流速影响。为改善消能效果及出口水流与下游的衔接,进行了多方案消能防冲改进试验,结果表明尾坎作为一种冲击式消能工布置在挖深式消力池末端,可使出口水流流速分布更加均匀并与下游水流衔接更为平顺,明显增强消能防冲效果。     

斜拉桥肋板式主梁剪力滞效应研究

大跨度斜拉桥剪力滞效应十分突出,在设计和施工过程中应考虑剪力滞效应的影响。根据能量变分原理,推导出肋板式主梁截面的剪力滞系数简易计算公式。以某460米主跨预应力混凝土斜拉桥为研究对象,采用大型空间有限元分析程序MIDAS FEA 3.3进行三维实体有限元数值分析,并与通过能量变分法计算得到的剪力滞系数比较发现,宽度较大的肋板式主梁剪力滞效应突出,且跨中处截面剪力滞系数小,而塔根处的截面剪力滞系数大,在设计和施工过程中应采取必要的措施保证结构安全。     

折板跌落式竖井设计约束条件研究

结合国内深层隧道排水工程-广州市东濠涌深层排水隧道,通过物理模型试验探讨了不同折板间距情况下折板竖井消能规律,并根据竖井中水流在折板间需满足的过流能力及充分消能的约束条件,研究了折板竖井消能的最大过流流量及稳定消能边界,提出了折板竖井设计应同时满足的约束条件以及折板通气孔的推荐位置。研究表明,在折板间距与折板宽度的比值小于0.408时,约束条件只有最大过流能力;当比值大于0.408时,只需考虑充分消能的约束条件。     

跌坎型底流消能工的跌坎最小深度研究

跌坎型底流消能工消力池内的水力特性受到跌坎深度的影响。应用平面紊动射流理论,以消力池内允许的最大时均动水压强为控制目标,对于跌坎最小深度的确定方法进行了初步分析,建立了计算跌坎最小深度值的理论公式。通过水力学试验方法,得到消力池底板时均动水压强与跌坎最小深度之间的关系,同时与跌坎最小深度试验值进行了比对,对本文建立的理论公式进行了验证。     

Water–energy–food nexus in a transboundary context: the Euphrates–Tigris river basin as a case study

The interlinkage between water, energy and food security and its transboundary relevance is becoming increasingly important. The paper analyses the evolution of transboundary water resources management in the Euphrates–Tigris basin with specific reference to interlinkages between water, food and energy policies at national and transboundary levels, and it explores how the policy shifts at the highest decision-making level have served to produce synergies for cooperation among the riparians or vice versa.