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排序方式: 共有770条查询结果,搜索用时 147 毫秒
721.
通过分析减排量核查报告,得出2014年政策实施带来了6078.20万t CO2e的三氟甲烷(HFC-23)减排,占“十二五”氢氟碳化物(HFCs)累计减排目标的21.7%。此外,通过分析政策面临的问题,从监测方法学、政策设计和后续运行监管3个方面,对政策的后续运行及2020年后HFC-23的减排提出了建议。 相似文献
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723.
基于“本体-认识-方法”论的逻辑范式,从关系范围和主驱力两个视角重新界定了滨海旅游的基本内涵,认为滨海旅游与海岸旅游和海洋旅游具有交叉关系,是在一定的社会经济条件下,以沿海岸线陆域和海岸为依托,以满足人们精神和物质需求以及不同经济主体利益为目的而进行的海陆观光、休闲和度假等旅游活动所产生的现象和关系的总和;结合国内外发展实践认为滨海旅游应有独特的滨海生态与人文资源、较长的可游憩时间、优越的区位条件和交通环境、较好的海陆经济产业发展、较高的开发技术支撑和强烈的海洋意识培养等六方面特性;基于内涵界定并遵照滨海旅游发展模式构建的市场经济驱动、不同主体参与、地方特色强化和游憩环境保护4项原则,从管理经营、空间布局和要素开发等3个关键领域系统地提出了滨海旅游发展的政府主导与企业驱动相结合的管理经营模式、“集聚-联动”驱动的空间布局模式、RMIP要素开发模式,以期为沿海城区滨海旅游地建设和完善提供了理论和实践的双重借鉴。 相似文献
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城市轨道交通造成环境的振动“污染”不容忽视。通过现场测试和理论分析,得到南京地面轨道交通运行引起的大地竖向振动加速度幅值、频率随距离轨道中心线不同位置的衰减规律,即随着与轨道水平距离的增加,大地竖向振动加速度幅值总的趋势表现为逐渐减弱,但在距离轨道中心线20~30 m之间振动幅值有所反弹;振动加速度的频率集中在0~ 100 Hz,最大值出现在30~80 Hz左右,随着与轨道水平距离的增加,各频率的振动信号分量总的趋势是减弱,且频率愈高衰减愈快。基于“北京交通大学”预测公式,建立包含受振点距离、地基土性质、列车速度3个参数的南京地面轨道交通运行引起大地振动的预测模型,与实测数据相比,吻合较好。 相似文献
726.
Evaluation of stochastic reservoir operation optimization models 总被引:5,自引:0,他引:5
This paper investigates the performance of seven stochastic models used to define optimal reservoir operating policies. The models are based on implicit (ISO) and explicit stochastic optimization (ESO) as well as on the parameterization–simulation–optimization (PSO) approach. The ISO models include multiple regression, two-dimensional surface modeling and a neuro-fuzzy strategy. The ESO model is the well-known and widely used stochastic dynamic programming (SDP) technique. The PSO models comprise a variant of the standard operating policy (SOP), reservoir zoning, and a two-dimensional hedging rule. The models are applied to the operation of a single reservoir damming an intermittent river in northeastern Brazil. The standard operating policy is also included in the comparison and operational results provided by deterministic optimization based on perfect forecasts are used as a benchmark. In general, the ISO and PSO models performed better than SDP and the SOP. In addition, the proposed ISO-based surface modeling procedure and the PSO-based two-dimensional hedging rule showed superior overall performance as compared with the neuro-fuzzy approach. 相似文献
727.
Probabilistic reservoir operation using Bayesian stochastic model and support vector machine 总被引:3,自引:0,他引:3
Available water resources are often not sufficient or too polluted to satisfy the needs of all water users. Therefore, allocating water to meet water demands with better quality is a major challenge in reservoir operation. In this paper, a methodology to develop operating strategies for water release from a reservoir with acceptable quality and quantity is presented. The proposed model includes a genetic algorithm (GA)-based optimization model linked with a reservoir water quality simulation model. The objective function of the optimization model is based on the Nash bargaining theory to maximize the reliability of supplying the downstream demands with acceptable quality, maintaining a high reservoir storage level, and preventing quality degradation of the reservoir. In order to reduce the run time of the GA-based optimization model, the main optimization model is divided into a stochastic and a deterministic optimization model for reservoir operation considering water quality issues.The operating policies resulted from the reservoir operation model with the water quantity objective are used to determine the released water ranges (permissible lower and upper bounds of release policies) during the planning horizon. Then, certain values of release and the optimal releases from each reservoir outlet are determined utilizing the optimization model with water quality objectives. The support vector machine (SVM) model is used to generate the operating rules for the selective withdrawal from the reservoir for real-time operation. The results show that the SVM model can be effectively used in determining water release from the reservoir. Finally, the copula function was used to estimate the joint probability of supplying the water demand with desirable quality as an evaluation index of the system reliability. The proposed method was applied to the Satarkhan reservoir in the north-western part of Iran. The results of the proposed models are compared with the alternative models. The results show that the proposed models could be used as effective tools in reservoir operation. 相似文献
728.
Optimization of the Sefid-Roud Dam desiltation process using a sophisticated one-dimensional numerical model 总被引:1,自引:0,他引:1
Ali KHOSRONEJAD 《国际泥沙研究》2009,24(2):189-200
Although water and soil conservation activities reduce reservoir sedimentation, it is inevitable that reservoirs fed by rivers transporting high amounts of sediment will experience sedimentation. The Ghezel-Ozan and Shah-Roud rivers, which flow to the Sefld-Roud reservoir dam, are both highly sediment-laden and transport significant amounts of sediment in both bed load and suspended load forms to the reservoir. Hence, it seems that the only practical way to remove the sediment from the reservoir is to flush it out using the Chasse method. In the present paper, field measurements of Chasse operation characteristics taken in previous years are presented, and a numerical model that simulates this process is introduced. After calibrating the model using field measured data, the calculated results (for reservoir pressure flushing and released sediment volume) of the numerical model were compared with other measured data for the same Chasse operation and the results agree well. Finally, using the numerical simulation results, the best approaches to ensure highly effective flushing while conserving reservoir water are presented (at least for the Sefid-Roud dam). The operation of the bottom outlet gates, the shape of the output hydrograph, and the reservoir water level variation during flushing were optimized. In addition, the numerical model and related parameters, which need to be calibrated, are discussed. 相似文献
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