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121.
文章通过对青海野生大黄的生态环境、分布状况、群落特征、开发现状、存在问题的分析和论述,提出未来青海野生大黄资源开发必须遵从生态保护为先,生态、生产、经济、社会效益共同持续的原则,强化资源保护和基础技术研究,加大人工驯化裁培力度,不断满足日益增长的市场需求。  相似文献   
122.
砼芯水泥土复合桩是一种新型的基坑支护方法,即在水泥土搅拌桩中插入钢筋混凝土预制小方桩,形成一种新的复合桩体,兼有受力和止水的双重作用,并采用两排中间用圈梁相连的门型结构提高了支护结构的受力特性。该支护方案在南京某深基坑工程中得到了成功应用。本文分析了该新方法的结构特点、简要介绍了其设计计算方法,并结合有限元数值模拟和实际的监测数据与排桩方案进行分析比较。研究结果表明,该新型基坑支护形式取得了良好的支护和经济效果,具有重要的应用前景。  相似文献   
123.
The transboundary River Nestos in the Balkan Peninsula is a surface water resource shared by Hellas and Bulgaria. The Public Power Corporation of Hellas (DEH) proceeded to the dams' construction of Thesaurus in 1997 and Platanovrissi in 2000, to satisfy the increased needs for power production and irrigation in the Regions of Eastern Macedonia and Thrace in the Hellenic Territory. DEH following the Ministerial Agreement of the Hellenic Parliament ‘`KYA 18492/19—09—1996’' funded a series of Research Projects concerned on the monitoring of the water quantity and quality data of Nestos from the Hellenic-Bulgarian borders to its estuaries in the Thracian sea. ‘`PERSEAS’' Research Group from Aristotle University of Thessaloniki, carried out the research, design, construction, installation, operation and maintenance of the ‘`R.E.MO.S.’' (Remote Environmental MOnitoring System) networks. Three REMOS networks have been installed in the areas of (a) the River Nestos deltaic channel, (b) Thesaurus dam-lake in the intramountainous valley and (c) Potamoi (Despat) and Pagoneri (Nestos) villages close to the borders between Hellas and Bulgaria. They record water level (H), water and air temperature (T), water conductivity (ECw), Redox potential (RP) and dissolved oxygen (DO) on a 24h basis, since the beginning of the year 2000. The research carried out in this paper, is focused on the REMOS station in the final course of Nestos in the deltaic area. The continuous monitoring and the data analysis yield useful results for the quality and quantity of the hydrologic regime of Nestos after the dams' construction, as well as for the trends detected of the quality parameters (ECw, RP and DO) and the water level, using the nonparametric Spearman's criterion. The best fitted model of time trend, for each variable, was chosen. The statistical sample of each one of the quality variables consisted of about 1000 values based on daily measures on a three years monitoring program (1/1/2000—31/12/2002). Further research and analysis for the other network stations of REMOS should provide useful results for the sustainable management of the transboundary River Nestos.  相似文献   
124.
Surface and core sediment samples were collected from Lake Ayg?r, Turkey, to determine heavy metal distribution, probable sources and potential ecological and toxic risks for the lake. Heavy metals, total sulfur, total phosphate, total organic carbon, chlorophyll degradation products, and CaCO3 content were established. The enrichment factor, PLI, potential ecological risk index, and toxic risk index were calculated. Zn was determined to have the highest accumulation in surface sediment, followed by Cr, Pb, and Cd, respectively. Cd was the only element that exceeded the critical value of 40 and posed a moderate potential ecological risk. According to TRI, no ecotoxic risk was found. It is thought that local fossil fuel consumption is responsible for the accumulation of heavy metals since there is a lack of urbanization, industrialization, and agricultural activities around the lake.  相似文献   
125.
响应曲面法优化电化学氧化技术处理染料废水   总被引:2,自引:0,他引:2  
采用IR和XRD等手段对自制磷钼酸铁(FePMo12)杂多酸进行表征,表明杂多阴离子具有Keggin结构。将FePMo12负载于修饰后的分子筛上制备FePMo12/APTES-4A催化剂填充于电化学反应器中,考察电化学氧化体系对酸性大红3R染料废水的脱色效果,其脱色率高于二维电化学反应器。利用Box-Behnken中心组合实验设计及响应面(RSM)分析,以pH值,板间距,槽电压,曝气量为实验因素,建立了以酸性大红3R的脱色率为响应值的二次多项式回归模型。研究表明,当电解时间为60 min时,曝气量0.05 m3/h、pH为2、板间距3.0 cm、槽电压11.0 V,在此条件下色度去除率可达69.4%,模型预测值与实验值能很好地吻合。方差分析结果表明,槽电压和pH、pH和曝气量的交互作用对响应值具有显著性影响。  相似文献   
126.
Along the coast facing the Pacific Ocean in the province of Esmeraldas (Ecuador) one can observe some stretches where a process of rapid erosion is currently in progress. If it is not prevented, it seriously risks compromising the development of any form of utilization. In this paper, which summarizes the observations carried out in three different periods (1989, 1992 and 1999), we express the opinion that this process is the product of two distinct main causes. Along the Atacames bay, which may be considered as the main seaside resort of Quito, the capital of Ecuador, progressive cliff retreat is not only very dangerous for the existing tourist settlements, but also hinders their further development. The shoreline dynamics that seems to be due only to ‘natural’ causes (sea level rising, or the lastEl Niño event) are so active that defence works are not recommended. At Camarones the erosion of the coast is clearly due to the systematic destruction of mangroves by man. Also as a result of the lastEl Niño event, the situation has become alarming and it could rapidly get worse. By means of the present contribution, the Authors intend to attract the attention of the international scientific community upon the processes, not surveyed so far, affecting the ‘weakest’ stretches of the Ecuadorian coast.  相似文献   
127.
在对我国能源R&D强度分析的基础上,运用DEA理论的C^2R模型对我国能源产业及其5个行业2001--2010年的R&D经费投入、产出状况进行了实证分析。研究中用R&D经费存量值来代替当年的R&D经费值,得到各年的R&D经费配置的相对效率和规模收益情况,找出R&D经费配置配置存在的问题,有利于对我国能源R&D经费的投人产出结构进行分析,提出优化国家能源R&D经费配置的对策和建议。  相似文献   
128.
An intense waste management (WM) planning activity is currently undergoing in England to build the infrastructure necessary to treat residual wastes, increase recycling levels and the recovery of energy from waste. From the analyses of local WM strategic and planning documents we have identified the emerging of three different energy recovery strategies: established combustion of residual waste; pre-treatment of residual waste and energy recovery from Solid Recovered Fuel in a dedicated plant, usually assumed to be a gasifier; pre-treatment of residual waste and reliance on the market to accept the ‘fuel from waste’ so produced. Each energy recovery strategy will result in a different solution in terms of the technology selected; moreover, on the basis of the favoured solution, the total number, scale and location of thermal treatment plants built in England will dramatically change. To support the evaluation and comparison of these three WM strategy in terms of global environmental impacts, energy recovery possibilities and performance with respect to changing ‘fuel from waste’ market conditions, the LCA comparison of eight alternative WM scenarios for a real case study dealing with a large flow of municipal wastes was performed with the modelling tool WRATE. The large flow of waste modelled allowed to formulate and assess realistic alternative WM scenarios and to design infrastructural systems which are likely to correspond to those submitted for approval to the local authorities. The results show that all alternative scenarios contribute to saving abiotic resources and reducing global warming potential. Particularly relevant to the current English debate, the performance of a scenario was shown to depend not from the thermal treatment technology but from a combination of parameters, among which most relevant are the efficiency of energy recovery processes (both electricity and heat) and the calorific value of residual waste and pre-treated material. The contribution and relative importance of recycling and treatment/recovery processes change with the impact category. The lack of reprocessing plants in the area of the case study has shown the relevance of transport distances for recyclate material in reducing the efficiency of a WM system. Highly relevant to the current English WM infrastructural debate, these results for the first time highlight the risk of a significant reduction in the energy that could be recovered by local WM strategies relying only on the market to dispose of the ‘fuel from waste’ in a non dedicated plant in the case that the SRF had to be sent to landfill for lack of treatment capacity.  相似文献   
129.
运用R/S(Rescaled Range Analysis)方法,对芜湖市1953—2006年共54年间的气温、降水、相对湿度、日照等气象要素资料的年平均、冬季、夏季进行了分析计算。计算表明,各指标的Hurst指数均大于0.5,说明4个气象指标存在明显的Hurst现象,反映出芜湖市气候变化的特征与趋势,并预测了芜湖市气候未来的发展趋势,证明城市化已经对芜湖市气候变化产生了显著影响。  相似文献   
130.
The effects of cycle time on the biodegradation of the azo dye remazol brilliant violet 5R (RBV-5R) were investigated in an anaerobic–aerobic sequencing batch reactor (SBR). System performance was determined by monitoring chemical oxygen demand (COD), color, anaerobic enzyme (azo reductase) and aerobic enzyme (catechol 2,3-dioxygenase), and aromatic amine concentration. SBR was operated in three different total cycle times (48 h, 24 h and 12 h), fed with a synthetic textile wastewater. In this study, the anaerobic period of SBR was found to allow the reductive decolorization of azo dye and the aerobic period was found to be effective on further COD removal after the anaerobic period. The percentage reductions in color by the anaerobic stage of the SBR were at 72%, 89% and 86% for the 24-h, 12-h and 6-h cycle times, respectively. Total COD removal efficiencies were over 75% for all operational conditions and about 70% of the COD removal was achieved in the first 3 h of anaerobic stages. During the decolorization of RBV-5R, two sulfonated aromatic amines (benzene-based and naphthalene-based) were formed and detected by HPLC. Aerobic phases of SBR with total cycle times of 48 h, 24 h and 12 h were able to remove benzene-based aromatic amines with removal efficiency of 64%, 92% and 89%, respectively. The results indicated that the best SBR performance in terms of color removal and aromatic amine degradation was achieved from total cycle time of 24 h.  相似文献   
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