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481.
介绍了高浓度氨氮废水的来源和危害,综述了高浓度氨氮废水的处理技术与研究动态,总结了各处理技术的优缺点并分析了技术发展方向. 相似文献
482.
实验分析了6大类14种直接染料在兼氧条件下的降解性能和脱色效果。在未加葡萄糖的实验中,采用不同温度(20℃与35℃)和不同停留时间来测定染料的降解性能。结果表明,35℃下的最佳停留时间为48h,此时的COD。的去除率及脱色均有较好的效果,而在72h的停留时间下,降解效果无明显提升。20℃下最佳停留时间则为72h,此时的COD。去除率及脱色效果与35℃下的结果很接近。在添加葡萄糖的实验中得到结果证实了葡萄糖作为在共代谢作用中的碳源对促进染料的降解起到非常积极的作用。 相似文献
483.
484.
Abstract Taking Shandong Province as the research object, this paper uses the principal component analysis method to evaluate the status of the rural human settlement in Shandong Province. It establishes the evaluation index system of the rural residential environment in Shandong Province, including living environment, economy, infrastructure, public service facilities, and ecological environment, in total five comprehensive index, and 20 secondary indexes. Through measurement and sorting of rural human environment development level of Shandong Province in 2010, the 17 cities are divided into-excellent, good, ordinary, poor-four development areas and are analyzed based on the restriction factor in the development of the region. 相似文献
485.
Impacts of pollution controls on air quality in Beijing during the 2008 Olympic Games 总被引:1,自引:0,他引:1
Shen J Tang A Liu X Kopsch J Fangmeier A Goulding K Zhang F 《Journal of environmental quality》2011,40(1):37-45
Air pollution has become one of the main environmental concerns in China since the 1980s due to China's rapid economic growth and resultant pollution. However, it is difficult to directly evaluate the anthropogenic contribution to air pollution in China. The 2008 Olympic Games in Beijing provided a unique opportunity for testing the contribution of anthropogenic pollution because of the clean-up controls on air quality in Beijing enforced over the period of the Games. In this case study, we monitored the concentrations of major air pollutants before, during, and after the Olympics at a suburban site in Beijing. Atmospheric concentrations of PM10, PM2.5, NH3, NO2, SO2, and the particulate ions NH4+, NO3-, SO4(2-) Ca2+, Mg2+, and K+ all decreased during the Olympic period because of strict emission controls, compared with the same period from 2005 to 2007. For example, the average PM10 concentration (61 microg m(-3)) during the Olympics was only 37% of that (166 microg m(-3)) in the same month (August) from 2005 to 2007. However, just 1 mo and 1 yr after the Games had ended, mean concentrations of these pollutants had increased significantly again. This rapid "recovery' of air pollutant concentrations after the Olympics suggests that China needs to implement long-lasting decreases in its air pollution in Beijing and other major cities. 相似文献
486.
Development of Customized Fire Behavior Fuel Models for Boreal Forests of Northeastern China 总被引:3,自引:1,他引:2
Knowledge of forest fuels and their potential fire behavior across a landscape is essential in fire management. Four customized
fire behavior fuel models that differed significantly in fuels characteristics and environmental conditions were identified
using hierarchical cluster analysis based on fuels data collected across a boreal forest landscape in northeastern China.
Fuel model I represented the dense and heavily branched Pinus pumila shrubland which has significant fine live woody fuels. These forests occur mainly at higher mountain elevations. Fuel model
II is applicable to forests dominated by Betula platyphylla and Populus davidiana occurring in native forests on hill slopes or at low mountain elevations. This fuel model was differentiated from other fuel
models by higher herbaceous cover and lower fine live woody loading. The primary coniferous forests dominated by Larix gmelini and Pinus sylvestris L. var. mongolica were classified as fuel model III and fuel model IV. Those fuel models differed from one another in average cover and height
of understory shrub and herbaceous layers as well as in aspect. The potential fire behavior for each fuel model was simulated
with the BehavePlus5.0 fire behavior prediction system. The simulation results indicated that the Pinus pumila shrubland fuels had the most severe fire behavior for the 97th percentile weather condition, and had the least severe fire
behavior under 90th percentile weather condition. Fuel model II presented the least severe fire potential across weather conditions.
Fuel model IV resulted in greater fire severity than Fuel model III across the two weather scenarios that were examined. 相似文献
487.
氦气是发展国防军工和高科技产业不可或缺的战略性物资之一.由于氦气在自然界中的富集度很低,目前工业规模化提氦来源主要是含氦天然气.常用的提氦方法有吸附法、吸收法、低温冷凝法、膜分离法等,但它们都不能很好地解决提氦难度大、成本高、规模化工业应用水平较低等缺点.因此,引入水合分离技术,利用含氦天然气各组分生成水合物的条件差异在水合反应过程中对氦气提浓,同时辅以催化脱氢工艺,实现粗氦的精制. 相似文献
488.
489.
The present study simultaneously examined people's perceptions of person–organization (PO) and person–supervisor (PS) fit and related these perceptions to employees' commitments. Three‐hundred‐and‐sixty employee–supervisor dyads from Taiwanese organizations reported about their PO fit and PS fit perceptions. In addition, supervisors reported about their perceptions of fit and guanxi with each of their employees. Results indicated that PO and PS fit perceptions both had an independent and additive relationship with organizational commitment. The link between employee PS fit perceptions and organizational commitment was mediated by commitment to the supervisor. Both employee and supervisor fit perceptions contributed to commitment to the supervisor through their influence on the quality of the leader‐member exchange (LMX). Guanxi could not explain additional variance in LMX and supervisor commitment. Implications for theory and practices regarding person–environment fit, commitment, and LMX are discussed. The study findings offered suggestions for a new Theory of Multiple Fits. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
490.
采用盆栽试验,分别向磁器口土样(土壤1)、校园土样(土壤2)中添加不同质量比的Cd及不同质量比的Zn+ Cd(20 mg/kg),研究不同质量比外源CA及Zn+Cd(20 mg/kg)复合污染对两种土壤中绿豆苗株高及绿豆苗吸收Cd的影响.结果表明:单一外源不同质量比Cd污染绿豆苗时,生长期为7d的绿豆苗株高较对照组有明显下降,随Cd污染加剧,绿豆苗生长受到抑制,随生长期延长而其危害加剧;随Cd污染的加剧,绿豆苗中Cd质量比增加,并呈正相关性,相同污染水平下,生长期为7d的绿豆苗Cd质量比均大于生长期为3d的;在不同污染水平下,土壤1的绿豆苗株高高于土壤2,其绿豆苗Cd质量比低于土壤2;Zn+ Cd(20 mg/kg)复合污染时,株高较对照组矮,绿豆苗中Cd质量比随着Zn质量比增加而增加,呈正相关,表现为协同作用;对比土壤1和土壤2,土壤2的株高较低,但其绿豆苗中Cd质量比在不同水平下均高于土壤1. 相似文献