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881.
扬州生态市建设中景观生态规划的应用 总被引:6,自引:0,他引:6
在扬州根据景观生态规划的原则,通过对自然、经济和社会条件的分析,形成市域范围内的生态敏感地区分布图,并提出相应的发展对策;在沿江地带,根据自然演变和经济发展,提出扬州沿江地带保护自然发展动力轴线、强化经济轴线的总体布局;根据城市发展目标和廊道建设情况,提出在中心城区沿润扬大桥北接线建设1km的环城绿色廊道,建设城市东西方向的3条绿色廊道和南北方向的两个楔形开放空间,同时沿主要的水网建设沿岸防护廊道,形成作为城市冷桥的绿色网络结构,把城市和郊区联系在一起,加强空气的流通并减轻、预防热岛效应和其他城市弊端。 相似文献
882.
To examine whether the interaction between bumblebees, Bombus ignitus, reduces their foraging area, we conducted bee-removal experiments in a net cage. In the cage, we set potted Salvia farinacea plants, allowed bumblebees to forage freely on those plants, and followed their plant-to-plant movements to identify a bee with a relatively small foraging area. We then removed all the other foraging bees, except for the bee with a small foraging area, and observed the change of the foraging area of the focal bee under conditions of no interaction with other bees. After the removal of the other bees, all five bees tested enlarged their foraging areas, suggesting that the interaction between bees is an important determinant of their foraging areas. The result also means that bumblebees are able to adjust their foraging areas in response to other foragers, indicating the necessity for future studies to clarify what cues bees use to interact with other bees. Moreover, after the removal treatments, all five bees showed temporary increases in the number of flower probes per plant. This can be explained by their optimal foraging according to the old average intake rate for the plant population and by the delayed changes in response to the new high average energy intake rate after the bee-removal treatments.Communicated by M. Giurfa 相似文献
883.
德国高等职业教育的特点 总被引:4,自引:1,他引:4
基于了解德国“双元制”职业教育基础上,介绍了德国职业教育体系,研究了高等职业教育模式、入学条件、培养目标、培养模式、学制、文凭以及人才培养途径,分析了高等职业教育的师资培养措施与过程、经费保障以及法律保障,阐述了高等职业教育改革的基本目标、基本原则、改革重点、发展趋势以及基本理念. 相似文献
884.
885.
This study was conducted to biologically treat wastewater discharged from the textile industry (textiles made of cotton and/or synthetic fiber) using sequencing batch reactor (SBR) technology (activated sludge process operating on batch mode). To achieve the objectives of the study, the characteristics of textile wastewater and the biodegradation of its organic constituents under unsteady state conditions were studied. Then, a bench-scale pilot plant was used to study the performance of SBR by monitoring the settleability and change in the constituents (chemical oxygen demand and solids) over time. Results of the study showed that textile wastewater has different types of pollutants: heat, basicity, suspended solids, organic and inorganic matter, and heavy metals. The factors affecting the biodegradation of organic matter were determined as the reaction time and the ratio of initial substrate to sludge concentrations. Also, removal of solids was monitored, and the settling velocity as affected by sludge concentration was graphically presented to enable the determination of settling time. Finally, the outcome of this study was used to suggest a procedure for the design of a full-scale SBR unit for treatment of textile wastewater. 相似文献
886.
Modeling Desertification Change in Minqin County,China 总被引:1,自引:0,他引:1
Monitoring environmental processes is becoming increasingly important wherever there is increasing population and economic development pressure placed on fragile environments. Remote sensing, digital image processing, and spatial analysis have proven to be useful technologies in both assessing and monitoring environmental change. In this study, they were used to assess desertification processes and change in Minqin County, China from 1988 to 1997. The results suggest that wind erosion was the dominant cause of desertification in more than half of the study area. Coupled with this were increases in salinization processes, affecting 33.62% of the land area in 1997. Overall, moderate desertification was found to be the dominant desertification grade (43.64% of total area), followed by extreme/severe desertification (26.15% of total area) in 1997. In addition, examination of landscape pattern changes indicated that desertification processes at the landscape level were becoming evident at increasing levels of fragmentation, complexity in shape, and isolation of patches. Major fluctuations in desertification type and grade were found at the fringes of oases, where an ongoing shift was taking place between cultivation, abandonment, and reclamation. 相似文献
887.
In this paper we analyse an ordination method in which spatial contiguity information is included. The original method, proposed by Ver Hoef and Glenn-Lewin (1989), is extended, using graphs to describe spatial contiguity for several sampling schemes where locations are given. Extensions for two dimensional grids and for the case of discrete measures of abundance are analysed. Applications to simulated transect frequency data and real data collected on a regular grid are reported. 相似文献
888.
作物布局是农业生产的一个重要环节,直接关系到农业生态系统资源输入(物质条件、科学技术、气候资源和生物资源等)的利用和转化效率的高低。因为系统输入的资源是非定常的,尤其是天气气候条件年际之间是不同的,本文在年型预测的基础上,确定在不同天气气候条件下的作物合理布局。 相似文献
889.
890.
东莞华兴电器厂生活污水人工快速渗滤处理系统 总被引:23,自引:1,他引:23
以渗透性能良好的天然砂作为主要渗滤介质建立人工快速渗滤系统处理生活污水 ,在东莞华兴电器厂进行了为期 1a的中试工程试验研究。结果表明 ,在不 <1m d的水力负荷条件下 ,人工快速渗滤系统对生活污水具有较强的抗冲击负荷能力和较好的污染物去除效果 ,其对SS、CODCr 和BOD5的平均去除率分别为 94 14 %、91 99%和94 4 4 % ;处理出水中SS、CODCr、BOD5、NH3 N及LAS的平均浓度分别为 4 0 6、2 3 2 0、9 0、5 16和 0 2 6mg L。采取间歇性淹水 落干的运行方式 ,并结合反冲洗 ,提高了CRI系统的水力负荷 ,改善了污染物去除效果 ,增强了其实用性。 相似文献