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311.
基于水质评价的综合污染指数(CWQI)法和水质指标实测含量的统计分析,应用Monte Carlo模拟方法,建立了河流水质评价的Monte Carlo-CWQI耦合模型并进行实例研究.通过建立的耦合模型和温瑞塘河流域14个监测断面2004~2010年的水质监测数据,定量分析各监测断面隶属于不同污染等级的概率水平和各水质指标对水体污染的影响程度.结果表明:温瑞塘河水系水质污染十分严重,勤奋、九山、东水厂、十字河、南白象、灰桥、新桥、米筛桥、仙门、光明、郭溪、瞿溪、西岙和梧田监测断面处于重度污染的概率分别为28.50%,0.55%,92.71%,59.73%,78.85%,39.38%,78.87%,83.09%,65.32%,78.08%,0.00%,0.96%,68.09%,86.06%;处于严重污染的概率分别为71.28%,0.01%,4.33%,39.76%,21.07%,60.59%,4.42%,12.41%,11.02%,21.24%,0.00%,0.02%,1.42%,13.12%.各监测断面总氮(TN),氨氮(NH3-N)和溶解氧(DO)的Spearman等级相关系数范围分别是0.41~0.76、0.25~0.63和0.14~0.66,是其他指标的2倍以上,表明影响该地区水质达标的主要因子是TN,NH3-N和DO.本研究拓宽了河流水质评价的研究视角,能够为流域水环境管理提供丰富的决策依据.  相似文献   
312.
Efficient removal of non-biodegradable and hazardous dyes from wastewater remains a hot research topic. Herein, a rationally designed a Cu(Ⅱ)-based metal–organic gel(Cu-MOG) with a nanoporous 3 D network structure prepared via a simple one-step mixing method was successfully employed for the removal of cationic dyes. The Cu-MOG exhibited high efficiency, with an adsorption capacity of up to 650.32 mg/g, and rapid adsorption efficiency, with the ability to adsorb 80% of Neutral Red within 1 min. The high adsorption efficiency was attributed to its large specific surface area, which enabled it to massively bind cationic dyes through electrostatic interaction, and a nanoporous structure that promoted intra-pore diffusion. Remarkably, the Cu-MOG displayed size-selective adsorption, based on adsorption studies concerning dyes of different sizes as calculated by density functional theory. Additionally, the adsorption performance of the Cu-MOG still maintained removal efficiency of 100% after three regeneration cycles. These results suggested that the Cu-MOG could be expected to be a promising and competitive candidate to conveniently process wastewater.  相似文献   
313.
介绍了一种小子样成败型产品可靠性评估方法。基于"计量评估"理论原则,针对可用于评价产品的特征量的试验数据,依次运用了数据样本子样的概率分布拟合检验方法、样本数据的一致性检验和离群值识别等统计学方法,最终使用经检验的特征量试验数据完成产品的可靠性评估。使用实例数据,应用评估方法,完成了一类典型产品的可靠性评估,其中特别指出的是,在实际应用过程中,应该尤其关注离群值的识别和剔除。实例证明,此方法可用于特征量明确的小子样成败型产品的可靠性评估。  相似文献   
314.
This report summarizes the surveys on carbon inventories and initiatives on sustainable carbon cycling taken by RCEES. The first part of this report deals with the concept of sustainable carbon cycling, the historical evolution of carbon cycling processes in China, carbon pool enhancement, value addition, carbon sequestration and carbon balance. The second part covers the modeling of carbon dynamics, emission inventories of various carbon containing greenhouse gases and their potential abatement measures.  相似文献   
315.
文章论述了我国农村生态环境问题与乡镇企业发展形势,提出依靠科学技术发展乡镇企业,推动农村生态环境建设,促进我国农业持续发展的设想。  相似文献   
316.
Qiu Y  Ling F 《Chemosphere》2006,64(6):963-971
While synthetic polymeric sorbents effectively treat dye wastewaters by adsorption, the underlying mechanisms remain to be understood. This work determined the adsorption of an anionic dye by three polymers differing significantly in surface functionality. Surface functional groups of polymers were indicated in FTIR spectra and quantified by the Boehm titration. In reference to the commercial sorbent XAD-4 with a low degree of functionality, the laboratory synthesized NG-8 had primarily acidic functional groups, whereas its aminated product MN-8 had mainly basic amino groups. Electrophoresis determined the points of zero charge of 4.18, 3.23, and 4.51 for XAD-4, NG-8, and MN-8, respectively. The adsorption of Reactive Black 5 dye (RB5) by all the sorbents on a unit surface area basis increased with decreasing pH. At the same low pH (4.40), the adsorption by NG-8 was similar to that by XAD-4, indicating little influence of protonated (neutral) surface functional groups. In contrast, the adsorption by NG-8 at pH 6.05 was 75% lower than that by XAD-4, resulting apparently from the strong electrostatic repulsion between RB5 and deprotonated (negative) groups. Amination substantially enhanced RB5 adsorption by eliminating acidic groups and creating a positive charge on the surface of MN-8. The adsorptive enhancement was also achieved in the presence of CaCl2, due presumably to the neutralization of negative surface charge by Ca2+ and the RB5-Ca2+ pairing. These results manifest the important role of surface functionality in the adsorption of dyes by synthetic polymers.  相似文献   
317.
OBJECTIVE: The study aimed to explore the distribution and correlates of subjective sleepiness among the general night-time driving population. METHODS: The survey took place in three British Columbia communities in June 2003 between 21:00 hours to 03:00 hours. Sites and vehicles were selected randomly. Surveyors obtained information on several demographic and situational variables including self-assessed degree of sleepiness and self-reported hours asleep and awake, as well as an objective measure of blood alcohol concentration obtained from a hand-held breath-testing device. RESULTS: The total compliance rate among intercepted drivers was 85%. Among the 2335 drivers responding to the questionnaire, 68.4% indicated that they were wide awake, 27.6% were somewhat sleepy, and 4.1% were very sleepy. Logistic regression quantified the independent contributions of the various factors to subjective sleepiness. Male drivers with positive blood alcohol concentrations under 50 mg% were more likely to report feeling sleepy than those with either higher or with zero blood alcohol concentration. Greater relative risk of sleepiness was also associated with being female, being under age 55, and advanced hour of night. Driving with passengers of the same gender was associated with lower reported sleepiness. CONCLUSIONS: A substantial proportion of night-time drivers are driving while sleepy, especially at late night and early morning hours. The combination of alcohol and sleepiness compounds impairment in experimental studies and deserves greater attention in crash risk studies and as a topic for public education and awareness.  相似文献   
318.
黄泥土不同粒径微团聚体对Cd2+的吸附与解吸研究   总被引:9,自引:1,他引:8  
王芳  李恋卿  潘根兴 《环境科学》2006,27(3):590-593
对采自太湖地区黄泥土进行了低能量超声波分离,采用平衡吸附法研究了不同粒径微团聚体颗粒对重金属Cd2+的吸附和解吸特点.结果表明,不同粒径微团聚体对Cd2+的吸附特性均符合Freundlich方程,模拟方程得到的K值介于152~503之间,以粘粒级和粗砂级为最大.微团聚体对Cd2+的吸附容量与其中游离氧化铁含量、CEC呈显著正相关.不同微团聚体Cd的解吸特点不同,粘粒级的解吸率仅为8.4%,远远低于其它粒径的微团聚体,这些结果有助于了解田间条件下土壤重金属化学行为和微观尺度的化学过程.  相似文献   
319.
通过分析现有OFA系列石油定量分析仪的使用对操作人员的职业危害,从试剂对人体的危害程度、对油气发出荧光的干扰程度、油气萃取灵敏度与萃取荧光效率、钻井液添加剂选择性进行对比实验提出了采用异丙醇代替正已烷作为萃取剂的可能性,并对工作台进行改造,将有害气体迅速排除,降低室内有害气体浓度,从而实现“绿色”操作的方法。  相似文献   
320.
建筑安全管理的PDCA循环   总被引:8,自引:0,他引:8  
建筑业是我国国民经济的支柱产业之一,建筑业生产的产品为国民经济的发展奠定了重要的物质基础。同时,建筑业也是一个危险性高、易发生事故的行业,是国家安全生产专项治理的重点行业之一。近年来,建筑业安全管理的现状和建筑施工现场的诸多不安全因素影响了整个建筑业效益的提高,也是建筑业及建筑施工现场不能吸引高素质人才的主要原因之一。安全管理具有系统性、连续性等特点,本文将全面质量管理的PDCA循环模式应用于建筑安全管理.探讨了建筑业安全管理的全新方法及其操作过程,借以降低建筑安全事故率,提高建筑业生产率,增加效益。  相似文献   
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