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141.
孙国平 《水电站设计》2007,23(3):105-109
从流域和区域对水资源需求及环境保护要求出发,提出了在大樟溪干流刘岐、岩前和莒口增设鱼道、取消船闸和航运的建议;从流域环境保护要求提出了主要水库的最小下泄流量;根据大樟溪流域人口、经济及土地资源的状况,提出了从泉州、莆田和福州等水资源受益区安置移民缓解土地资源紧张的模式来提高龙湘水库的调节库容,以提高流域及区域对水资源需求与调配能力,确保河道生态安全、生产生活用水安全等流域规划的新思路、新理念。  相似文献   
142.
河流生态用水流量确定新方法研究   总被引:3,自引:1,他引:2  
新修改的《中华人民共和国水法》明确提出要维持江河的生态用水流量,以维持水体的自然净化能力,确保健康河流。经过对多种计算方法分析、比较,提出了河流生态用水流量的内涵与计算方法,该法简单可行,不但有一定的理论价值,而且有一定的实用价值,可供实际工作参考使用。  相似文献   
143.
M A Ramaswamy 《Sadhana》1987,10(3-4):445-458
The theoretical aerodynamic characteristics of a typical lifting symmetric supercritical airfoil demonstrating its superiority over thenaca 0012 airfoil from which it was derived are presented in this paper. Further, limited experimental results confirming the theoretical inference are also presented. Invited Lecture given at the 3rd Asian Congress on Fluid Mechanics, held in Tokyo during 1–5 September, 1986  相似文献   
144.
计算机系统在钢卷库库区管理上的应用   总被引:1,自引:0,他引:1  
主要介绍了钢卷库过程计算机系统(CYC)管理库区的方法,包括钢卷的堆放方式、库区管理的策略,以及平整生产等内容,并且简述了CYC系统的运行情况。  相似文献   
145.
对2004年中国证券市场上的129家金属和非金属行业上市公司的会计账面盈利与现金流量的相关性进行实证研究后,发现两者的相关程度很低,很大一部分上市公司的账面盈利没有形成相应的现金流入,导致两者之间产生“滞脱”的效应.因此,笔者认为在对企业的财务状况进行评价时,不能仅仅局限于使用一些反映企业账面盈利的指标,应该还需要考虑一些反映企业创造现金流量能力的指标.  相似文献   
146.
Open window buses without air-conditioning are a major mode of urban and inter-city transport in most countries. High occupancy combined with hot and humid conditions makes travel in these buses quite uncomfortable. In this study air flow through a bus has been studied that could be the basis for low cost and eco-friendly methods of increasing passenger comfort and possibly reduce drag. The aerodynamics of such a road vehicle has not been studied as previous investigations have been confined to vehicles with closed windows that present a smooth exterior to air flow. Using a 1:25 scaled Perspex model of an urban bus in Delhi, flow visualization was performed in a water channel. The Reynolds numbers were one-tenth of a real bus moving at 10 m/s. Smoke and tuft visualizations were also performed on an urban bus at 40 km/h. Numerical simulations were performed at the actual Reynolds number. Even though there were Reynolds number differences, the broad features were similar. Air enters the bus from the rear windows, moves to the front (relative to the bus) and exits from the front windows. Inside air velocity relative to the bus is about one-tenth of the free-stream velocity. The flow is highly three-dimensional and unsteady.  相似文献   
147.
In this work, optimal shaft shapes for flow in the annular space between a rotating shaft with axially-periodic radius and a fixed coaxial outer circular cylinder, are investigated. Axisymmetric steady flows in this geometry are determined by solving the full Navier-Stokes equations in the actual domain. A measure of the flow field, a weighted convex combination of the volume averaged square of the L2-norm of the velocity and vorticity vectors, is employed. It has been demonstrated that boundary shape can be used to influence the characteristics of the flow field, such as its velocity component distribution, kinetic energy, or even vorticity. This ability to influence flow fields through boundary shape may be employed to improve microfluidic mixing or, possibly, to minimize shear in biological applications.  相似文献   
148.
Technological determinism has become a kind of religion for many people since it appears to offer solutions for societal problems as never before in history. Transport is one of the fascinating technology branches developed during the last 200 years. Effortless movement over long distances has become possible for car users as long as cheap fossil energy is available. However, the effect of fast transport on urban structures and society was not taken into account when developing these technical means. Technologists and economists have used indicators for expected benefits of these fast transport modes without taking into account the real system effects on society and urban structures. Plausible assumptions and hopes instead of scientific understanding of the complex system are used in practice. In contradiction to widely held beliefs of transportation planners, there is actually no growth of mobility if counted in number of trips per person per day, no time saving by increasing speed in the system, and no real freedom of modal choice. Modal choice is dependent on physical and other structures, the artificial environment built by urban planners, transport experts and political decisions. The core hypothesis of traditional urban and transport planning ‘growth of mobility’, ‘travel time saving by increasing speed’ and ‘freedom of modal choice’ are myths and do not exist in the real urban and transport system. This is the reason why urban planning and transport planning based on traditional non-scientific assumptions is creating continuously not only more transport problems, but also environmental and social as well as economic problems all over the world, where these principals are applied. Urban transport planning in Europe, understanding the transport system and the solutions are presented in this paper.  相似文献   
149.
In the present investigation, the newly developed Higher Order Semi-Compact (HOSC) finite difference scheme has been tested for its capability in capturing the very complex flow phenomenon of unsteady flow past a rotating and translating circular cylinder. The physical problem has been modeled in stream function and vorticity formulation and the obtained governing equations are transformed into curvilinear coordinates using body fitted coordinate system to enable the developed scheme to handle the non-rectangular geometry of the problem. Qualitative and quantitative comparisons have been done at low-rotation parameters and found that the results obtained are in excellent agreement with the existing literature. Then simulations have been carried out at high-rotation parameters and noticed that the HOSC scheme is able to simulate some of the flow features known experimentally but not simulated numerically to the present date.  相似文献   
150.
余秀峰  付海生 《天津冶金》2003,(6):42-43,46
介绍了35t/h锅炉扩容改造为55t/h非标锅炉的技术成功经验。从增加锅炉的容积、受热面面积、燃烧器喷嘴改造三个方面介绍了对锅炉本体的改造,改造后实现了锅炉的水位、汽温及燃烧自动调节,提高了锅炉的热效率为以后的锅炉扩容改造提供了实践经验。  相似文献   
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