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211.
本文研究了稻麦两熟养鱼高产的调控原理,提出了稻麦连作,畦麦沟鱼、稻鱼共生的稻田全年养鱼技术。①利用深沟窄畦扩容和稳容,改造生境容量;②采用畦麦沟鱼、稻鱼共生结构调节群落的种群密度和生态位宽度,延长养鱼时间;③按照生物种群的生态型对水层敏感性实施田间水位和流水增氧调控,提高养鱼产量;④提高稻麦两熟养鱼的生产率,合理投入,以生物质能为主源输入稳定系统结构。 相似文献
212.
Xianglong Luo Yongzhen Wang Jun Zhao Ying Chen Songping Mo Yulie Gong 《International Journal of Green Energy》2016,13(1):14-27
With the drastic decrease in fossil resources and rapid deterioration of the global environment, the utilization of geothermal resources has been strongly advocated. The combination of heat, power, and cold utility generation is commonly used to increase the utilization efficiency of geothermal resources. In this study, an integrated cascade utilization system of waste geothermal water (ICUWGW) from a flash geothermal power plant in China is established to increase the utilization efficiency of geothermal water. The waste geothermal water leaving the power plant is proposed for further use in cascade for two-stage LiBr/H2O absorption cooling, agricultural product drying, and residential bathing. Twelve candidate temperature schemes showing different inlet and outlet temperatures of every subsystem are proposed for the ICUWGW. Several criteria are selected for the evaluation and screening of the candidate schemes. Grey relational analysis incorporating analytic hierarchy process is conducted to screen the optimal temperature scheme for the ICUWGW to meet the comprehensive criteria of thermodynamics and economics. Results show that the optimal scheme features significant improvement in energy efficiency, exergy efficiency, and equivalent electricity generation efficiency compared with those of the current geothermal power plant. The investment payback time of the additional subsystems for cooling, drying, and bathing is 1.85 years. Exergy analysis is also conducted to determine the further optimization potential of the optimal ICUWGW. Sensitivity analysis of electricity price on the performance of the optimal ICUWGW is also performed. 相似文献
213.
水坝建设往往忽略了生态影响,轻视了社会问题,高估了经济效益.介绍了国际上对水坝问题认识的最新进展和主要观点,分析了我国水坝建设的现状和问题--西部建坝热潮不退的原因.从现状来看,中国的已建水坝已使长江流域生态退化,加剧了黄河的断流,加重了淮河水质的恶化等.最后以科学发展观为指导,对中国的水坝建设作了一些深层的思考. 相似文献
214.
Xiaoye Zhang Lei Zhang Jianjun He Sunling Gong Xiaomei Guo Tianliang Zhao Huizheng Che Hong Wang Chunhong Zhou Jingyue Mo Ke Gui Yu Zheng Lei Li Junting Zhong 《环境科学学报(英文版)》2023,35(1):535-544
The role of PM2.5 (particles with aerodynamic diameters ≤ 2.5 µm) deposition in air quality changes over China remains unclear. By using the three-year (2013, 2015, and 2017) simulation results of the WRF/CUACE v1.0 model from a previous work (Zhang et al., 2021), a non-linear relationship between the deposition of PM2.5 and anthropogenic emissions over central-eastern China in cold seasons as well as in different life stages of haze events was unraveled. PM2.5 deposition is spatially distributed differently from PM2.5 concentrations and anthropogenic emissions over China. The North China Plain (NCP) is typically characterized by higher anthropogenic emissions compared to southern China, such as the middle-low reaches of Yangtze River (MLYR), which includes parts of the Yangtze River Delta and the Midwest. However, PM2.5 deposition in the NCP is significantly lower than that in the MLYR region, suggesting that in addition to meteorology and emissions, lower deposition is another important factor in the increase in haze levels. Regional transport of pollution in central-eastern China acts as a moderator of pollution levels in different regions, for example by bringing pollution from the NCP to the MLYR region in cold seasons. It was found that in typical haze events the deposition flux of PM2.5 during the removal stages is substantially higher than that in accumulation stages, with most of the PM2.5 being transported southward and deposited to the MLYR and Sichuan Basin region, corresponding to a latitude range of about 24°N-31°N. 相似文献
215.
216.
Constructed wetlands (CWs) have been successfully used for treating various wastewaters for decades and have been identified as a sustainable wastewater management option worldwide. However, the application of CW for wastewater treatment in frigid climate presents special challenges. Wetland treatment of wastewater relies largely on biological processes, and reliable treatment is often a function of climate conditions. To date, the rate of adoption of wetland technology for wastewater treatment in cold regions has been slow and there are relatively few published reports on CW applications in cold climate. This paper therefore highlights the practice and applications of treatment wetlands in cold climate. A comprehensive review of the effectiveness of contaminant removal in different wetland systems including: (1) free water surface (FWS) CWs; (2) subsurface flow (SSF) CWs;and (3) hybrid wetland systems, is presented. The emphasis of this review is also placed on the influence of cold weather conditions on the removal efficacies of different contami-nants. The strategies of wetland design and operation for performance intensification, such as the presence of plant, operational mode, effluent recirculation, artificial aeration and in-series design, which are crucial to achieve the sustainable treatment performance in cold climate, are also discussed. This study is conducive to further research for the understanding of CW design and treatment performance in cold climate. 相似文献
217.
本文对不同林分的土壤最大持水力、土壤毛管持水力、枯落物最大持水量和枯落物最大持水率进行分析,得出不同林分枯落物和土壤持水能力的关系. 相似文献
218.
从川西高原饮用水赋存的环境-地质条件出发进行研究,较全面的探讨了该区气象、水文、土壤等环境要素对水中氧化还原电位的制约作用.通过对研究区内饮用水赋存环境的一系列环境地质调查与氧化还原电位的现场测试可以得出:(1)该研究区所处特殊的地理位置(青藏高原的东南部一横断山系北段,属川西高山高原区)导致该区具有冬长,无夏,春秋短,气温低,温差大等独有的气象条件;该区主要的构造侵蚀高山地貌类型导致地下水循环具有径流途径短,水力坡度大,水～土间交换作用十分强烈的特点,该区土壤的特点是淋滤作用较强且成弱酸性等,这三个环境要素的特点是直接导致该区饮用水中氧化还原电位值升高的主要原因;(2)由于不同类型水(河水、沟水、泉水、土井水)其与大气接触程度的差异导致其氧化还原值呈现由高到低的趋势,即河水>沟水>泉水>土井水. 相似文献
219.
Donghua Xie Changbiao Liang Yueyun Xiang Aihua Wang Lili Xiong Fanjuan Kong Haoxian Li Zhiyu Liu Hua Wang 《黑龙江环境通报》2020,40(8):925-930
220.