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91.
黄河上游梯级水电站施工洪水优化设计方法探讨--以黄河公伯峡水电站施工洪水优化设计为例 总被引:1,自引:0,他引:1
梯级水电站设计洪水方法一直是梯级水电站水文设计的难点.几十年来在黄河上游梯级电站设计中已总结出一套比较完整的设计洪水及施工洪水计算方法。通过黄河公伯峡水电站施工洪水优化设计过程,论述了该套方法.并就目前存在的一些观点及疑问给予了较为明确的回答。 相似文献
92.
建设用地地质灾害危险性评估中几个问题的思考 总被引:7,自引:3,他引:7
金德山 《中国地质灾害与防治学报》2004,15(4):101-103
结合工作实践,就建设用地地质灾害危险性评估及其成果审查工作中经常遇到的5个问题——评估灾害类型的确定原则,评估区环境条件分析深度的把握,现状、预测及综合地质灾害危险性评估内容的侧重点,土地适宜性评价的依据以及优秀评估成果的判定标准,提出了个人的理解和认识。供从事类似工作的同志参考。 相似文献
93.
The design of roadbed-abutment transition part is always a challenging problem in transportation engineering, especially in permafrost distribution zone. A new type of roadbed-abutment transition part on permafrost was presented, and long-term observation was conducted for the deformation and the thermal regime of a roadbed-abutment transition part in the constructing Qinghai-Tibet Railway. In this paper, a new structure was presented and the observed settlements both in the subgrade and the base and its dependency with the thermal regime (permafrost table) were analyzed. In conclusion the roadbed-a-butment transition method for permafrost distribution zone was evaluated. 相似文献
94.
95.
新材料是发展高新技术产业的基础。根据广西的矿产资源优势和在矿物材料方面的研究基础和技术力量,提出了加强工艺矿物学研究,大力发展广西新型矿物材料的研究开发方向,特别提出了超细改性矿物粉体材料、环保矿物材料、节能保温矿物材料、高技术陶瓷材料和合成矿物晶体材料等材料体系中的重点开发方向。 相似文献
96.
97.
六四式军用梁应用于遂川江特大桥40mT梁侧向架梁中,笔者详细地介绍了架梁设备的主要结构,以及架梁施工技术与操作方法,并对军用梁架梁设备进行系统验算,架梁设备达到安全要求。并进行了经济技术分析,应用该架梁方案,大大降低了施工成本。 相似文献
98.
Helen Ruth Aspaas 《GeoJournal》2004,61(3):281-289
Women in many rural areas of the US often engage in small-scale businesses as one of several avenues for contributing to household
incomes. In those geographical areas that contain a significant minority population, many of the women's businesses display
the cultural diversity of the regions in which they live. Likewise, women's roles as economic providers as well as wives and
mothers are reflected in the manner in which they operate their businesses. Candida Brush suggests that women's strategies
for operating their businesses are highly integrative because women's business decisions are intertwined with familial responsibilities,
household economic demands and desires to contribute to their communities. Hispanic and Native American women in the Four
Corners region of southwestern US and African American women in central Virginia participated in interviews in which they
responded to numerous short answer and open-ended questions about their businesses and decision-making strategies. From these
interviews an image emerges of rural minority business women who are operating their businesses at the nexus of family obligations,
economic necessities, cultural ties and with a commitment for serving their communities.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
99.
Problems associated with tourism development in Southern Africa: The case of Transfrontier Conservation Areas 总被引:2,自引:0,他引:2
Sanette Ferreira 《GeoJournal》2004,60(3):301-310
Tourism in Southern Africa is synonymous with the wildlife safari. In the post-colonial era the establishment of so-called
‘peaceparks’ that straddle the borders of states has come to be seen as a key not only to increasing tourism in the Southern
African region, but also to the modernizing of conservation policies and the development of rural economies. This paper focuses
on the global and continental presence of transfrontier conservation areas, the link between conservation and tourism development,
and the current factors that constrain and influence the realization of an ‘African Dream’ — ‘establishment of the greatest
animal kingdom’. The unstable political situation in Zimbabwe and how this negatively affects wildlife conservation and tourism
in the Gonarezhou part of the Greater Limpopo Transfrontier Park, serves as a case study.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
100.
声波钻进是在各种覆盖层中采集连续岩心样品的有效手段。叙述了声波钻进技术的发展情况、工作原理、设备操作、优越性和用途,并且对我国研发此项技术提出了建议。 相似文献