黄河黑山峡河段大柳树水库比小观音水库原始库容多40亿m3的作用

一级开发大柳树高坝原始库容比二级开发小观音高坝多 4 0亿m3 ,库容大带来的好处体现在 5～ 7月可多向下游增供水量 ,缓解下游河道断流 ;延长泄放清水时间 ;增加发电效益 ;满足宁蒙河段防凌要求 ;增加汛期集中泄水 ,减缓下游河道淤积萎缩 ;满足南水北调西线工程水量调节要求等。为了更好优化配置黄河水资源 ,从全局和长远利益考虑 ,应采用一级开发方案 ,修建大柳树高坝大库     

永定新河治理工程几个关键问题的研究

永定新河是天津市防洪的北部防线。由于受海相来沙淤积 ,河道行洪能力大幅度下降。针对永定新河治理工程设计中涉及到的河道淤积治理方案、闸位比选、防潮闸结构型式及施工方法、闸下减淤清淤措施等诸多问题进行了分析和研究 ,提出了相应的措施和建议     

非均匀河床上的丁坝局部冲刷问题

对丁坝局部冲刷问题进行研究,采用坝头绕流挤压流动模式,建立非均匀河床上的丁坝局部冲深公式.     

关于混凝土四面体截流材料的探讨

通过对比混凝土四面体与特大块石这两种截流材料的抗冲稳定性和施工的方便性,分析了混凝土四面体截流材料在工程应用中存在的问题。指出:①混凝土四面体密度、综合稳定系数、化引球形粒径都偏小,在龙口的抗冲稳定性不如特大块石;②混凝土四面体制作麻烦,成本高,占地面积大,装运困难,抛投强度低,施工不如特大块石方便;③在截流施工中宜优先使用特大块石,慎用混凝土四面体。     

Modelling the effects of dam removal on migratory walleye (Sander vitreus) early life‐history stages

Many dams in the USA have outlived their intended purpose and an increasing number are being considered for removal. Yet, quantitative studies of the potential physical, biological and ecological responses are needed to assess dam removal decisions. In this paper, the responses of migratory walleye (Sander vitreus) to increased spawning habitat availability as a result of dam removal was studied by comparing scenarios with and without a high‐head dam in the Sandusky River (Ohio), a major tributary to Lake Erie. A conceptual, ecological model was proposed to define the relationship between hydrodynamics and walleye spawning, egg hatching, larval drift and survival. A mathematical, ecological model of the early life‐history stages was then developed and coupled with time series of depth and velocity predictions over the spawning grounds from a 1‐D hydrodynamic model. Model simulations were run for 1984–1993 for both the with‐ and without‐dam scenarios to assess the potential benefit of dam removal. The simulation results demonstrated that velocity, depth and water temperature are major factors influencing adult walleye spawning success. Without the dam, 10 times the amount of spawning habitat would be available for walleye to spawn. This increase in spawning habitat area resulted in up to five times the total egg deposition and seven times the larval output to the nursing grounds, based on the assumption that 5% of the walleye population of Lake Erie migrated up the Sandusky River to spawn. We concluded that the spawning habitat in the current condition (with the dam) is limiting and additional spawning habitat upstream could significantly increase the number of larval walleye drifting to Lake Erie. The model sensitivity analysis showed that the number of walleye migrating up the river in spring is the dominant factor for larval recruitment to the lake. Copyright © 2006 John Wiley & Sons, Ltd.     

从《左传》录诗看孔子是否删诗

孔子是否删诗，这是一个历史遗留问题。司马迁首言在前，孔颖达怀疑在后。宋之后，争议遂起，延至近代。今人夏传才先生断日：孔子是否删诗，“在没有发掘出新史料的情况下，哪怕再争论八百年，也是搞不清楚的”。以此止息纷争。话虽不错，但问题并没有解决。我认为，在没有发掘出新史料的情况下，可以从《左传》入手，来考察孔子是否删诗。     

主跨348m+348m三塔单索面PC梁斜拉桥

宜昌市夷陵长江大桥采用三塔斜拉桥，总体布置为(128．08 348 348 120．35)m。介绍了该桥的合理性及结构特点。     

色彩心理效应模型在人性化Web导购系统中的搭建与应用

人性化、个性化系统是现代Web商务系统的一个发展趋势,也是人工心理的一个研究方向。本文以服装选购系统为例,对人类情感的重要影响因素之一——色彩心理效应进行了进一步的深入研究。文中首次使用人工神经网络对色彩带来的膨胀紧缩感的心理效应进行数学建模,并且在服装导购系统中进行应用算法的设计和实施,从而实现了一种心理效应由感性描述到理性模型的转化,同时也使人性化、个性化智能系统的理念得到进一步完善。实验结果表明此数学模型能够较好的模拟色彩给人带来的膨胀紧缩感,在系统中的应用效果也收到了用户的好评。     

应用SPC技术对机械零件加工过程的管理和控制

介绍了SPC(统计过程控制)技术原理，以某传动轴外径φ45 0.50^0.90 mm为控制对象，提出应用SPC技术，对机械零件加工过程进行管理和控制，从而达到过程失控预警、过程不断改进、过程能力不断提高的目的，继而保证产品质量的稳定和不断提高。     

3G系统的安全策略分析

介绍了当前3G系统面临的各种威胁和针对3G的攻击方法,如对非授权数据的非法获取、对数据完整性的攻击和对业务的非法访问攻击等.分析了3G系统的安全体系结构和安全特性的优缺点.