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Taihu Lake, the third largest freshwater lake in China, is located in the Chanjiang Delta of the Yangtze River. Its waters are used by agriculture, industry and as major drinking water for several cities including Shanghai and Wuxi. The lake also is important for tourism, aquaculture and flood control. Taihu Lake and its surrounding areas are facing three major water-related threats: deteriorating water quality with inflow and runoff from its watershed; flooding during the rainy seasons; and water shortages during drier months. Noxious algae blooms are occurring with increasing frequency and water quality continues to decline. Remedial actions implemented to date have been ineffective. This paper proposes that the problems could be remedied by constructing a by-pass channel (BPC), which would divert low-quality water from the lake during low precipitation periods and allow better quality water to flow into the lake during high flow periods. This remedial action would simultaneously deal with the deteriorating water quality of Lake Taihu and maintain its water level at a desired level. A preliminary assessment of this strategy shows that, if the BPC were implemented, the water quality of Taihu Lake would be improved significantly in few years, the flood disaster would be greatly mitigated, and the water shortage problem in the basin would be alleviated.  相似文献   
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众多的软件开发过程到底是为我们解决的问题多,还是造成的问题更多?它们是否真的能够为改进团队的工作方式提供深刻的见解和所需的指导?文中对当代软件开发过程所面临的问题做了深刻的分析,并指出为什么我们现在拥有如此多的过程。  相似文献   
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针对同时兼顾大范围搜索和精确识别目标的迫切需求,研制了一种大变倍比红外变焦成像系统,设计两片独立运动的变倍镜及一片补偿镜,通过两个变倍镜级联的方式获得大变倍比。结合系统运动镜片多及变焦曲线复杂的特点,采用直线运动机构实现镜片变焦运动,使用集成编码器及螺纹丝杆的直线电机作为驱动。通过有限元仿真开展了系统力学分析,所设计镜片最大位移为3.04×10-3 mm。成像系统适用于中波红外制冷式640×512焦平面阵列探测器,变倍比达到55倍。实验室成像及外场实景成像的结果表明,系统在焦距由6 mm至330 mm连续变化的过程中成像清晰、像质良好,验证了系统的连续变焦成像性能,该设计合理可靠。研究成果在搜索、跟踪、侦察、监视等方面有广阔的应用前景。  相似文献   
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