交通运输网络可靠性研究分析

重点分析连通可靠性、出行时间可靠性、能力可靠性、行为可靠性和潜在可靠性等评价道路网络性能的指标,在回顾和总结交通网络可靠性研究发展的基础上,针对国内外的研究现状,提出了目前研究中存在的问题,描述了该领域有待研究的方向。     

大城市耕地资源人口承载力研究——以北京市为例

在全国城市化、工业化快速发展时期,北京等大城市耕地资源和粮食生产规模逐年下降,人口粮食需求对外依赖度提高,城市粮食保障度降低。以实证数据为基础对北京等大城市粮食安全问题进行了分析,结合乡村劳动力安置问题提出了保护大城市耕地资源的政策建议。     

山东半岛城市群相对资源承载力与竞争力研究

以山东半岛城市群为例，采用相对资源承载力的研究思路和计算方法，计算分析了其2000-2004年相对土地资源承载力、相对经济资源承载力和综合承载力及其演化过程。研究表明：①山东半岛城市群的土地资源对综合承载力的贡献大于经济资源，是山东半岛城市群人口的主要承载资源；②山东半岛城市群的综合承载力超过实际人口数量，处于相对富余状态；③相对资源承载力的地区差异较明湿，淄博、日照处于超载状态，其它处于富余状态；④相对土地资源承载力与相对经济资源承载力的小协调发展是提升山东半岛城市群竞争力需要重点解决的问题。     

铁路灾害线路通过能力损失评估模型

针对目前铁路抗灾减灾的实际需要 ,阐述了铁路灾害间接经济损失评估的重要性 ,论证了铁路灾害线路通过能力损失是铁路灾害间接经济损失的主要部分 ,并提出了铁路灾害线路通过能力损失的评估模型     

Land Cover and Use Changes in Relation to the Institutional Framework and Tenure of Land and Resources in Eastern Tanzania Miombo Woodlands

In Tanzania, well-defined land tenure and resource protection apply in forest reserves which account for 30% of forested land, while the remaining 70% (mostly miombo woodlands) are village and general lands with very limited protection. The aim of this study was to determine local peoples ownership rights, knowledge and institutional capacity for sustainable management of resources in forest reserves and general lands. Data were collected using participatory rural appraisal, structured and semi-structured interviews, as well as aerial photographs and landsat images. In general lands, woodlands declined by 50% between 1964 and 1996, bushlands and croplands increased by 599%, and settlements and homegardens increased by 277%. These land use and vegetation structure changes are attributed to harvesting for charcoal production and shifting cultivation. The continued decline in aerial woodland cover in the general lands suggests that common property regimes do not function in the area. Local institutional capacities are weak in enforcing control mechanisms to check the overuse of resources, which tends to approximate open access conditions. The issues of land tenure and village empowerment are not only institutional, but also political in nature. Government institutions should provide and motivate for an enabling environment, including acknowledgement of traditional knowledge, well-defined property rights and operational village by-laws. In order to ensure equity and sustainable development of natural resources, the paradigm shift in management is important whereby communal goods are to be managed for the benefit of the local society.     

现役钢筋混凝土受弯构件残余承载力计算模型

本文基于钢筋混凝土结构理论及锈蚀钢筋混凝土构件的力学性能的变化规律,建立了钢筋混凝土构件残余承载力的计算模型,并通过实验验证了计算模型的有效性.模型的物理概念明确、简单实用,可供现役混凝土结构的耐久性评估及维修决策参考.     

山东省沂沭河流域水环境容量研究

根据沂沭河流域的水文特征和水质状况，建立了沂沭河流域河流水环境容量数学模型和计算方法，依据该流域水环境功能区划，计算出流域内各水功能区和各河流的环境容量及最大允许排污量，从而为沂沭河流域实施水污染物总量控制和南水北调东线工程山东段水质达标提供基础数据。     

成都高新南区水污染物总量控制研究

在分析成都高新南区河流龙爪堰、栏杆堰水质现状的基础上，计算出区域水环境允许纳污量：COD331t／a、氨氮12t／a。目前高新南区水污染物排放现状为：COD464．28t／a、氨氮48.48t／a，已超过允许纳污量，因此必须对高新南区的水污染物进行削减。计算出了南区水污染物削减分配方案，并提出了保证区域总量控制目标实施的措施和意义。这为成都高新南区的水污染物实行总量控制提供了科学依据，并对其它中小区域水环境管理具有借鉴意义。     

Mine capacity and mineral price

The loss of foreign mineral supplies may affect domestic supply and price. To investigate the assumption that prices, a simple mine investment model that relates mine capacity to deposit attributes is used. A test of the model to see how well it approximates industry investment practice illustrates its accuracy. The model suggests that price changes can substantially affect the optimal capacity of planned or existing mines as well as the mineral supply in the USA.     

区域生态承载力与可持续发展

本文探讨了生态承载力的概念和估测的方法,分析了大陆典型生态系统净第一性生产力的背景值,研究了确定自然系统最优生态承载力的依据,在此基础上,提出了提高区域生态承载力,实现区域可持续发展基本对策。