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751.
属性识别理论模型在生态工业园综合评价中的应用   总被引:2,自引:0,他引:2  
属性识剐理论模型是近年提出来的一种数学模型,它已成功地用于质量评价中。现将该模型;1用到生态工业固综合评价中,运用所建模型对生态工业因进行了二级综合评价与实例分析,并与模糊综合评价模型相对照;实例分析结果表明,用属性识别理论模型评价的结果比用模糊综合评价模型评价的结果更加客观、合理,更能反映真实情况,而且计算简单,可用于不同类型生态工业园的综合评价,为生态工业园综合评价提供了一种简便实用的新方法。同时可为生态工业园的建设和管理提供科学参考依据。  相似文献   
752.
Objective: The primary purpose of this study was to examine the association between variations in visual behavior measures and subjective sleepiness levels across age groups over time to determine a quantitative method of measuring drivers' sleepiness levels.

Method: A total of 128 volunteer drivers in 4 age groups were asked to finish 2-, 3-, and 4-h continuous driving tasks on expressways, during which the driver's fixation, saccade, and blink measures were recorded by an eye-tracking system and the subjective sleepiness level was measured through the Stanford Sleepiness Scale. Two-way repeated measures analysis of variance was then used to examine the change in visual behavior measures across age groups over time and compare the interactive effects of these 2 factors on the dependent visual measures.

Results: Drivers' visual behavior measures and subjective sleepiness levels vary significantly over time but not across age groups. A statistically significant interaction between age group and driving duration was found in drivers' pupil diameter, deviation of search angle, saccade amplitude, blink frequency, blink duration, and closure duration. Additionally, change in a driver's subjective sleepiness level is positively or negatively associated with variation in visual behavior measures, and such relationships can be expressed in regression models for different period of driving duration.

Conclusions: Driving duration affects drivers' sleepiness significantly, so the amount of continuous driving time should be strictly controlled. Moreover, driving sleepiness can be quantified through the change rate of drivers' visual behavior measures to alert drivers of sleepiness risk and to encourage rest periods. These results provide insight into potential strategies for reducing and preventing traffic accidents and injuries.  相似文献   

753.
六价铬污染场地土壤稳定化修复材料研究进展   总被引:1,自引:0,他引:1       下载免费PDF全文
化学还原稳定化修复是工业铬污染土壤修复中应用最为广泛的技术。针对不同污染程度及理化性质的铬污染土壤,选择最为高效、经济、适用的稳定化修复材料是铬污染土壤修复工程最核心问题所在。针对上述问题,重点对现有铬污染土壤修复材料,如铁系、硫系、铁硫系、有机类及微生物菌剂的修复原理、影响因素、实际应用效果及存在问题、修复后环境风险和长期稳定性等多方面进行总结,为实际修复工程中六价铬修复材料的选择及修复实践工作的开展提供重要参考与指导建议。  相似文献   
754.
Coking industry is an important volatile organic compounds (VOCs) emission source in China, however, detailed information on VOCs emissions is lacking. Therefore, we selected a typical mechanized coking plant and collected air samples according to the Emission Standard of Pollutants for Coking Chemical Industry (GB16171-2012). Using gas chromatography-mass spectrometry method, we analyzed the VOCs in the air samples, and applied maximum increment reactivity (MIR) rule to estimate ozone formation potential (OFP) of the VOCs emitted from the coke production. More than 90 VOCs species were detected from the coking plant, including alkanes, alkenes, alkynes, aromatic hydrocarbons, halogenated hydrocarbons and oxygenated VOCs. The concentrations of VOCs (ρ(VOCs)) generated at different stages of the coking process are significantly different. ρ(VOCs) from coke oven chimney had the highest concentration (87.1 mg/m3), followed by coke pushing (4.0 mg/m3), coal charging (3.3 mg/m3) and coke oven tops (1.1 mg/m3). VOCs species emitted from the coke production processes were dominated by alkanes and alkenes, but the composition proportions were different at the different stages. Alkenes were the most abundant emission species in flue gases of the coke oven chimney accounting for up to 66% of the total VOCs, while the VOCs emissions from coke pushing and coal charging were dominated by alkanes (36% and 42%, respectively), and the alkanes and alkenes emitted from coke oven top were similar (31% and 29%, respectively). Based on above results, reduction of VOCs emissions from coke oven chimney flue gases is suggested to be an effective measure, especially for alkenes.  相似文献   
755.
756.
757.
采用共沉淀法制备了一种新型铁铜铝三元复合氧化物吸附剂,系统研究了其对磷的吸附行为,并对吸附磷前后的吸附剂进行了表征.吸附实验结果表明,铁铜铝三元复合氧化物对磷具有优异的吸附去除效能,Freundlich吸附等温线模型能更好地拟合其对磷的吸附,最大吸附量为62.6 mg·g-1(pH=7.0),显著高于多数文献报道的磷吸附剂;吸附速率较快,吸附动力学更符合Elovich模型;溶液pH对磷吸附有一定影响,随着pH的升高,磷吸附量降低,离子强度则影响不大;共存阴离子对磷吸附具有抑制作用,影响的大小顺序为SiO_3~(2-)SO_4~(2-)CO_3~(2-)Cl~-,而共存阳离子Ca2+和Mg2+则对磷吸附略有促进作用.Zeta电位、红外谱图(FTIR)和X射线光电子能谱(XPS)表征分析表明,磷在铁铜铝三元复合氧化物表面发生了特性吸附,磷酸根主要通过取代复合氧化物表面的羟基形成内表面络合物而被吸附去除.溶出实验结果表明,当pH在5.0~8.5范围内,Fe~(3+)、Cu~(2+)、Al~(3+)的溶出量均较低.由此可知,铁铜铝三元复合氧化物是一种具有良好应用前景的除磷吸附剂.  相似文献   
758.
以人工模拟废水为研究对象,采用4组SBR反应器(R0,R5,R10和R15),重点考察了碳氮比(C/N)对胞外聚合物(EPS)含量及其组分(蛋白质(PN)、多糖(PS)和核酸(DNA))的影响.试验结果表明:C/N对EPS及其组分具有显著影响.随着C/N由0升高至15,EPS和紧密结合型胞外聚合物(TB-EPS)含量逐渐升高,而松散型胞外聚合物(LB-EPS)含量逐渐降低,EPS以TB-EPS为主(占77.4%~93.6%).EPS和TB-EPS中的PN、PS和DNA含量随着C/N值升高而升高,LB-EPS中的PN、PS和DNA含量随C/N升高而降低.此外,随着C/N的增大,毛细吸水时间(CST)和污泥比阻(SRF)值显著增大,污泥的脱水性能变差.  相似文献   
759.
利用室内流水式粘油砾石柱模拟实际环境中的海底重燃油,研究了重燃油污染的孔隙水对成年海胆繁殖力、配子质量及子代胚胎发育的影响.结果表明,暴露结束后(7d),暴露组海胆的排配子率显著降低(P=0.033),同时雌海胆繁殖力也显著降低(P=0.036,(1957917±811471)个卵细胞);卵细胞的直径和精子的受精能力并未受到海底重燃油的影响.子代继续暴露48h,发现亲代暴露加剧了子代胚胎畸形程度,表明亲代暴露的毒性可传递给子代.进一步利用整合毒性指数(ITI)检测毒性传递的性别差异发现,与母本效应相比(24和48h子代的ITI分别为0.54~1.45和1.1~2.57),父本效应(24和48h子代的ITI分别为0.82~1.95和1.89~4.04)在毒性传递过程中起着关键作用.  相似文献   
760.
The studies on the human toxicity of nanoparticles (NPs) are far behind the rapid development of engineered functionalized NPs. Fullerene has been widely used as drug carrier skeleton due to its reported low risk. However, different from other kinds of NPs, fullerene-based NPs (C60 NPs) have been found to have an anticoagulation effect, although the potential target is still unknown. In the study, both experimental and computational methods were adopted to gain mechanistic insight into the modulation of thrombin activity by nine kinds of C60 NPs with diverse surface chemistry properties. In vitro enzyme activity assays showed that all tested surface-modified C60 NPs exhibited thrombin inhibition ability. Kinetic studies coupled with competitive testing using 3 known inhibitors indicated that six of the C60 NPs, of greater hydrophobicity and hydrogen bond (HB) donor acidity or acceptor basicity, acted as competitive inhibitors of thrombin by directly interacting with the active site of thrombin. A simple quantitative nanostructure-activity relationship model relating the surface substituent properties to the inhibition potential was then established for the six competitive inhibitors. Molecular docking analysis revealed that the intermolecular HB interactions were important for the specific binding of C60 NPs to the active site canyon, while the additional stability provided by the surface groups through van der Waals interaction also play a key role in the thrombin binding affinity of the NPs. Our results suggest that thrombin is a possible target of the surface-functionalized C60 NPs relevant to their anticoagulation effect.  相似文献   
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