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831.
城市绿地综合效益评价方法探讨:——天津实例应用   总被引:14,自引:0,他引:14  
本文从复合生态系统理论出发,建立了城市绿地综合效益评价指标体系并将AHP决策分析方法同模糊评价方法相结合,提出了一种城市绿地综合效益评价方法,同时,阐述了这一方法在天津的实际应用。  相似文献   
832.
Keshan disease (KD) occurs in a wide geographic belt stretching from the Heilongjiang Province in northeastern China to Yunnan Province in southwestern China, including Huangling County, Shaanxi Province. In order to research relationships between eco-environmental geochemistry and KD pertaining to Se, Mo, B, Zn, Mn, and Cu, this investigation was conducted in the Jiantou KD area in Huangling County, one of the areas in China where the incidence of KD is highest. Environmental samples (rock, soil, plant and childrens hair) were collected from the area. Se in plants is low, ranging from 0.03 to 0.06 µg Se g–1 in corn, potato and soybean. Se contents in childrens hair are normal or reach the limitation of dangerous level. This study reports 0.18 µg Se g–1, B <40 µg g–1, and Mo <1.0 µg g–1 in aeolian soil, 0.14–0.38 µg Mo g–1 and 3–8 µg B g–1 in corn and potato (daily staple food for local human beings in the area). The Jiantou KD area is one where the elements Se, Mo and B are deficient. It is proposed that the deficiency of elements Se, Mo and B may be involved in the pathogenicity of KD with respect to the eco-environmental system because Se, Mo and B are essential micronutrients for plants and human beings. It seems that there is no significant relationship between the Zn–Mn–K–Pb–Ba associations and KD.  相似文献   
833.
综述了红壤上施用磷矿粉对油菜产量、土壤铝毒和土壤化学性质的影响,认为磷矿粉直接施用于酸性土壤上,除增加土壤有效磷含量从而提高作物产量外,还能提高土壤pH值,增加交换性钙含量和降低交换态铝含量,增加土壤负电荷量,是一种低投入的土壤改良剂,在有条件的地区宜予推广。  相似文献   
834.
根据城市生活垃圾的特点和性质,利用物料平衡和热力学原理进行好氧堆肥实验装置的设计,并对堆肥发酵仓容积的确定和配套辅助设备进行了研究,得出当堆肥装置直径小于225m时,需采取保温措施。通过强制通风静态仓式堆肥小试实验进行的城市生活垃圾堆肥结果表明,通过30℃及以上的水浴加热,可实现固体废物的堆肥化。  相似文献   
835.
Lung SC  Hu SC 《Chemosphere》2003,50(5):673-679
The generation rates and emission factors of particulate matter and associated polycyclic aromatic hydrocarbons (PAHs) from incense burning were assessed in a laboratory setting. The differences among different segments of the same stick, among different sticks of the same kind of incense, and between two kinds of manually made Chih-Chen incense sticks (A and B) were evaluated. Joss sticks were burned inside a 44 cm long elutriator; personal environmental monitors fitted into the top of the elutriator were used to take PM2.5 and PM10 samples of incense smoke. Samples were analyzed for PAHs by gas chromatography-flame ionization Detector. It was found that particle and associated PAHs were generated approximately at 561 microg/min (geometric standard deviation (GSD) = 1.1) and 0.56 microg/min (GSD = 1.1) from Incense A, and at 661 microg/min (GSD = 1.7) and 0.46 microg/min (GSD = 1.3) from Incense B, respectively. One gram of Incense A emitted about 19.8 mg (GSD = 1.1) particulate matter and 17.1 microg (GSD = 1.2) particulate-phase PAHs, while one gram of Incense B produced around 43.6 mg (GSD = 1.1) of particles and 25.2 microg (GSD = 1.2) of particle-bound PAHs. There were significant differences in emissions between Incenses A and B, although they belong to the same class of incense. A 10-20% variability in emissions was observed in the main part of the manually produced stick, and a larger variation was found at both tips of the combustible part.  相似文献   
836.
污泥颗粒化快速启动厌氧氨氧化反应器的探讨   总被引:1,自引:0,他引:1  
厌氧氨氧化工艺处理成本低,被认为是有应用前景的废水脱氮技术.但是,厌氧氨氧化菌生长缓慢,厌氧氨氧化反应器启动困难.探讨了几种快速启动厌氧氨氧化反应器的方法,包括投加颗粒污泥、惰性载体、絮凝剂及多价阳离子等,并对其作用机理进行了分析.  相似文献   
837.
838.
火化过程中二噁英类污染物减排技术研究   总被引:1,自引:0,他引:1  
为减少火化过程中二噁英类污染物的排放,研究了"热交换器 布袋除尘器 活性炭纤维毡"三级组合对火化遗体烟气中二噁英类污染物的去除效果.利用急冷技术将二次燃烧室排出的火化烟气温度降到90~130℃.实验表明,布袋除尘器去除火化烟气中二噁英类污染物的效率为57.4%;布袋除尘器分别与厚度为5、15 mm的活性炭纤维毡组合去除火化烟气中二噁英类污染物的效率分别为64.0%和89.2%.  相似文献   
839.
Hu JY  Song LF  Ong SL  Phua ET  Ng WJ 《Chemosphere》2005,59(1):127-133
Biofouling control is considered as a major challenge in operating membrane systems. A lab-scale RO system was setup at a local water reclamation plant to study the feasibility of using biofiltration as a pretreatment process to control the biofouling. The biological activity in the RO system (feed, product, reject streams) was tested using the standard serial dilution plating technique. Operational parameters such as differential pressure (DP) and permeate flowrate of the system were also monitored. Effects of biofilter on AOC and DOC removals were investigated. Biofiltration was found to be a viable way of assimilable organic carbon (AOC) and dissolved organic carbon (DOC) removals, with removal efficiencies of 40-49% and 35-45% at an empty bed contact time (EBCT) of 30 min. It was also found that using the biofiltration as a pretreatment reduced the rate of biofouling. It took only about 72 h for biofouling to have a significant impact on the performance of the RO membrane, when the system was operated without using biofiltration as pretreatment. There was, however, a five times increase in operational length to more than 300 h when biofiltration was used. This study presented the suitability of the biofilter as an economical and simple way of biofouling control for RO membrane.  相似文献   
840.
Yu X  Trapp S  Zhou P  Hu H 《Chemosphere》2005,59(8):1099-1104
The response of cyanide metabolism rates of two woody plants to changes in temperature is investigated. Detached leaves (1.0 g fresh weight) from weeping willow (Salix babylonica L.) and Chinese elder (Sambucus chinensis Lindl.) were kept in glass vessels with 100ml of aqueous solution spiked with potassium cyanide for a maximum of 28 h. Ten different temperatures were used ranging from 11 degrees C to 32 degrees C. The disappearance of aqueous cyanide was analyzed spectrophotometrically. The cyanide removal rate of Chinese elder was higher than that of weeping willow at all temperatures. The highest cyanide removal rate for Chinese elder was found at 30 degrees C with a value of 12.6 mg CN kg(-1) h(-1), whereas the highest value of the weeping willow was 9.72 mg CN kg(-1) h(-1) at 32 degrees C. The temperature coefficient values, Q10, which are the ratio of removal rates at a 10 degree difference, were determined for Chinese elder and weeping willow to 1.84 and 2.09, respectively, indicating that the cyanide removal rate of weeping willow was much more susceptible to changes in temperature than that of the Chinese elder. In conclusion, changes in temperature have a substantial influence on the removal rate of cyanide by plants.  相似文献   
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