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991.
建立以水库群系统安全度最大、行蓄洪区系统损失最小为目标函数,将河道堤防安全行洪考虑为约束条件的复杂防洪系统多目标递阶优化调度模型(MoHOOM),以行蓄洪区总分洪流量为协调变量,将河道水流连续方程解耦,基于大系统分解协调法建立协调层和基于粒子群算法求解底层子系统优化问题,形成三级递阶分解协调结构和相应求解方法。以淮河中游防洪系统为背景进行了实例研究,给出了水库群泄流和行蓄洪区分洪最优方案,在相同初始计算条件下,优化模型结果比实际调度降低了鲇鱼山和梅山水库0.37和0.01的安全度指标,减小下游蒋家集和润河集河段超过安全泄量以上100 m3/s和720 m3/s的洪峰流量,启用南润段行洪区致损1 256.1万元;比规则调度降低了鲇鱼山和梅山水库0.24和0.21的安全度指标,减小下游蒋家集河段超过安全泄量以上750 m3/s的洪峰流量,避免南润段行洪区损失341.6万元。模型有利于挖掘上游水库群的防洪能力,在保障河道堤防安全行洪条件下,减少下游不必要的行蓄洪区分洪损失,以系统全局寻优方式进行复杂防洪系统联合调度。 相似文献
992.
灌区水资源合理配置是提高灌区水资源利用效率及保障粮食安全的重要途径,也是实现灌区水资源可持续利用的有效调控措施。从灌区水资源管理政策、水资源循环转化规律、水资源优化配置模型与方法和水文生态4个方面,对国内外该领域的研究现状进行了对比分析。研究发现,国内灌区水资源配置主要存在4个方面的问题:水资源合理配置与保护政策落实不到位、水资源的统一管理机制不健全、水资源优化配置模型实用性不强和水资源优化配置基础条件较为薄弱。建议加强灌区水资源的统一管理政策与机制、变化环境下水资源循环转化规律、水资源承载力基础理论与评价新方法、水文生态调控技术、水资源实时风险调度与智能化管理技术以及水资源优化配置耦合技术研究。 相似文献
993.
从城市供水系统的关键元素出发,通过系统网络拓扑分析,构建了"水源—水厂—分区用户"三层供水系统网络拓扑结构;基于此拓扑结构和兼顾整个供水系统的社会效益和供水成本两个调度目标,建立城市供水系统的多水源联合供水优化调度模型;利用NSGA-II(Non-dominated Sorting Genetic Algorithm II)算法进行模型求解,并给出最佳均衡解的选择规则;将该模型应用于南水北调中线一期工程通水后的天津市供水系统.实例研究结果表明,该模型实现了天津市不同来水丰枯组合情景下多种水源的合理分配,能够为决策者提供均衡社会效益与供水成本的详细供水方案,还可以在一定程度上反映出供水系统存在的工程问题,可为保障城市供水安全提供技术支撑.如最不利典型年来水情景下,总可供水量(14.73亿m3)大于天津市总需水量(13.77亿m3),但由于供水工程能力限制,特定供水规则下推荐的社会效益与供水成本折中方案的缺水量为2.44亿m3、总供水成本为32.6亿元. 相似文献
994.
针对黄土地层,提出利用空气代替钻井液的反循环气体喷射技术。但现有技术对反循环气体喷射钻头切削土体的能力没有具体优化讨论。利用fluent软件,优化反循环喷射钻头结构参数,对不同底喷孔直径、底喷孔数量、底喷孔扩大段直径、底喷孔扩大段数量、喷射孔数量5个结构参数进行模拟分析。分析结果表明,在进风流量一定的情况下,增加底喷孔的数量或增大底喷孔的直径会削弱钻头的空气射流切削能力和反循环能力。底喷孔直径为3 mm,底喷孔个数为2个,底喷孔扩大段直径为8 mm,底喷孔扩大段长度为5 mm,内喷孔数量为5个时,反循环喷射钻头喷射能力和反循环能力最优。 相似文献
995.
Molybdenum is one of the dominant minerals in China because of its rich reserves.In recent years,outstanding breakthroughs have been made in molybdenum prospecting in China,and the distribution of molybdenum deposits in China is found to have a "planar pattern".In general,the molybdenum deposits are concentrated in eastern China,including the largest molybdenum reserves of Henan Province.In terms of the scale of molybdenum deposits,the identified resources of the superlarge deposits are the most important,which account for about 53% of the whole country,and those of the large deposits account for about 30%,those of the medium-sized deposits account for about 14%,those of the small-sized deposits,mine spots and mineralization account for about 3%.The molybdenum deposits are mainly classified as porphyry type,skarn type,hydrothermal(vein) type and sedimentary(metamorphic) type in genesis,and the identified resources of these types account for 85.75%,8.83%,2.79%and 2.63% of the total resources respectively.Based on the statistics of precise chronology data of molybdenites Re-Os,Mo-mineralization can be divided into 6 periods in Chinese geological history,which are Precambrian(800 Ma),Cambrian-Silurian(540-415 Ma,Caledonian),Devonian-Permian(400-290 Ma,Hecynian),Triassic(260-200 Ma,Indosinian),Jurassic-Cretaceous(195-70 Ma,Yanshanian) and Paleogene-Neogene(65-10 Ma,Himalayan).Mo mineralization during the Yanshanian period is the strongest one,in which about 76.69% of the Chinese total identified resources was formed.The second is the Himalayan period.According to spatial-temporal distribution characteristics of molybdenum deposits,the metallogenic regularity of molybdenum deposits was preliminarily summarized,and 41 level-Ⅲ molybdenum-forming belts,13 level-Ⅱ molybdenum-forming provinces and 4 level-Ⅰ molybdenum-forming domains were ascertained in the mainland of China.There are 39 metallogenic series of and 60 sub-series of molybdenum deposits with molybdenum as the dominant metal and corresponding representative molybdenum deposits proposed.Metallogenic lineages of molybdenum deposits were also established.Spatial-temporal evolution of different types of molybdenum deposits,and the relationship between Mo-mineralization and tectonic evolution have been discussed in this paper.On this basis,the authors think that element Mo is an effective tracer for recording the crustal evolution history of China.At present,there are some problems in the exploration of Mo deposits in China,such as uneven exploration degrees in eastern and western China,shallow exploration depth,low and uneven grade,complex associated components,difficulty of mineral development and utilization,increasing costs of prospecting,and so on.According to successful experience of superficial and deep prospecting and considering also the discussion above,some suggestions are proposed for the prospecting of molybdenum deposits in the future. 相似文献
996.
997.
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?????????????λ????????????????????????????????????????????????????????????????????巨???????????????????ú???????2001~2004???GPS?????????????????????????????з????????????????б?????????????????????????Ч?????????????????????????????? 相似文献
998.
以优势高和地位指数的估测误差最小为目标函数,采用粒子群优化算法求解地位指数曲线模型的参数.结合实例与免疫算法比较,结果表明:粒子群优化算法求解的参数使模型的总体误差更小,精度更高,拟合效果更理想,更加科学合理,同时也提高了幼林的估算精度.研究的结果为森林经营中生长模型参数的求解以及相关研究提供了新的应用思路,也拓宽了粒子群优化算法在林业科学中的应用. 相似文献
999.
1000.
Advantages of the analytic element method for the solution of groundwater management problems 总被引:1,自引:0,他引:1
In the simulation‐optimization approach, a coupled optimization and groundwater flow/transport model is used to solve groundwater management problems. The efficiency of the numerical method, which is used to simulate the groundwater flow, is one the major reason to obtain the best solution for a management problem. This study was carried out to examine the advantages of the analytic element method (AEM) in the simulation‐optimization approach, for the solution of groundwater management problems. For this study, the AEM and finite difference method (FDM) based flow models were developed and coupled with the particle swarm optimization (PSO)‐based optimization model. Furthermore, the AEM‐PSO and FDM‐PSO models developed were applied in hypothetical as well as real field conditions to address groundwater management problems and the results were compared. For the real field situation, the models developed were applied to the Dore River basin in France to minimize the installation and operational cost of new pumping wells taking the location and discharge of the pumping wells as decision variables. The constraints of the problem were identified with the help of stakeholders and water authority officials. The AEM flow model was developed to facilitate the management model particularly when at each iteration, the optimization model calls for a simulation model to calculate the values of groundwater heads. The results show that, at some points, the AEM‐PSO model is efficient in identifying the optimal location of wells and consequently results in optimal costs, sometimes difficult when using the FDM. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献