建筑工人不安全行为发生机理研究

为梳理建筑工人不安全行为发生机理,对相关文献资料进行分析,基于建筑工人个体视角确定相关影响因素并构建不安全行为发生机理理论模型。结合现场访谈对模型进行修正后,采用结构方程模型处理问卷数据并对假设进行验证,最终确定建筑工人不安全行为发生机理。结果显示:安全认知与安全能力对建筑工人不安全行为影响关系显著,安全意识对建筑工人不安全行为影响关系不显著,且安全能力的影响程度要高于安全认知。     

不同进水条件下ASM1模型参数的灵敏度分析

编制了BSM1的仿真程序,并分析了不同进水条件下ASM1模型的16个参数对BSM1出水COD、TN、NH4+-N、NO3--N灵敏度的影响.结果表明,9个参数的灵敏度在规定的划分范围内没有区别,7个参数在不同进水条件下差别较明显;各参数灵敏度的变化规律,与出水的NH4+-N及NO3--N浓度变化有一定相关性;灵敏度变化与ASM1模型速率方程中的开关函数有关.研究不同进水条件下模型参数的灵敏度,有助于提高污水处理仿真计算的准确性.     

不同agro-生物质炭对水土两相中铵态氮的固持效应

应对农业固废利用率低及过度施肥带来的环境问题,以4种常见农业固废（花生壳,PS;瓜子壳,SS;稻壳,RH;甘蔗渣,BA）为材料,研究300、450和600℃热解制备的生物质炭对水体中铵态氮吸附效果。结果显示,等温吸附Freundlich模型相比Langmuir模型具有更好相关性,更加适合描述12种生物质炭对铵态氮吸附过程。BA300（K=0.54）的吸附能力最强,RH450（K=0.01）的吸附能力最弱。在1%、3%和5%（质量分数）施用量下,土壤对铵态氮的平衡吸附量随生物质炭投加量的增加而增大。结果表明,生物质炭的施加可以改变土壤理化性质,促进土壤对铵态氮的固持能力。     

Acetochlor as a soil pollutant

Acetochlor is a widely used herbicide all over the world. Similarly to other organic pollutants, the environmental fate of the acetochlor is strongly related to its adsorption properties. Static adsorption equilibrium measurements were carried out at 25 degrees C on different types of Hungarian soils characterized by varying amounts of organic matter and pH values. Isotherms obtained under different conditions, as well as on various soils, exhibit a similar shape, thus indicating a two-step adsorption process. The plots cannot be interpreted according to the classes of isotherms suggested by Giles. The adsorption coefficients (K) were estimated from the initial slope of the curves. These values were determined not only by the type of the soil, but also by the composition of the aqueous media. The organic matter adsorption coefficients (Kom) were also calculated and they were approximately identical for soils of high organic matter. Due to the low value of the adsorption coefficients, the acetochlor is a rather mobile pollutant of the soil posing a potential danger to the aquatic environment. For soils with high organic content, the Kom values are similar to each other and, due to the significant coverage of the inorganic surfaces, the adsorption is controlled by the solute-organic substance interactions. The adsorption of weakly polar compounds, however, is remarkable even on those soils where the organic content is low. In this case, the binding is governed by the solute-inorganic surface interactions. This conclusion is nicely proved by the adsorption of the acetochlor on quartz. According to our hypothesis, the second part of the adsorption step is controlled by the solute-adsorbed solute interactions. The role of the organic matter in this region of the isotherm is probably negligible. As the organic matter content of the soils plays an important role in the acetochlor adsorption, humic substances must have a strong influence upon the transport of this compound. Experiments to obtain adsorption isotherms of further pesticides and the development of a quantitative model are in progress.     

TiO2@碳纳米管吸附去除盐酸四环素

采用静电组装法制备了TiO2@碳纳米管复合吸附剂,用以除去水中的盐酸四环素。通过FE-SEM、EDS和XRD进行表征,考察了pH、初始浓度和吸附剂用量对吸附过程的影响,研究了吸附动力学、等温模型和热力学,并对吸附剂的再生进行了评价。结果表明,复合吸附剂对盐酸四环素的最大饱和吸附量为52.33 mg/g;最佳吸附pH值为6,强酸不利于吸附;当初始浓度在15~60 mg/L范围内时,吸附量随着初始浓度的增大而增加;当吸附剂投加量为0.50 g/L时,吸附效率最高。吸附过程符合准二级动力学模型和Langmuir等温模型。热力学参数ΔG H >0,表明该吸附过程是自发、吸热过程。H2O2-TiO2光催化协同效应可有效完成吸附剂的再生。     

废弃绿茶对水溶液中Co2+的吸附研究

利用废弃绿茶叶粉末(简称茶叶末)作为吸附剂,考察了pH、温度、时间等对水溶液中Co2+的影响。结果表明:(1)茶叶末对Co2+的吸附量随着pH的上升而上升,其中pH=5.50为最佳。茶叶末对Co2+的吸附量均随时间延长呈现上升趋势,吸附速度先快后慢,吸附最佳时间为90min。(2)不同温度下,茶叶末对Co2+的吸附较好地符合Langmuir模型。该吸附过程是化学离子交换过程,主要发生在重金属离子与羟基、氨基的氢原子之间。(3)茶叶末对Co2+的吸附是自发、放热过程,降温有利于吸附,反应时吸附界面上的混乱度增加。(4)盐酸是很好的解吸介质,解吸率为92.65%。通过灼烧(或燃烧)可以回收水溶液中绝大部分的Co2+,不仅减小了对环境的污染,而且节约了资源。     

煤质炭制备条件的优化及对酚类吸附性能与吸附动力学

KOH为活化剂,正交实验方法优化了煤质炭的制备条件。对2种酚类有机物苯酚、氯苯酚进行了静态吸附,观察了温度、时间、初始浓度及投加量对吸附性能的影响,优化了吸附条件。实验数据与Langmuir、Freundlich和Temkin吸附等温线进行了拟合,并对准一级、准二级动力学模型和内扩散模型拟合。结果表明,优化得煤质炭制备条件为:碱碳质量比3:1,浸泡时间12 h,活化时间80 min,活化温度800℃。在温度为25℃,投加量为0.05 g时,苯酚的平衡时间为60 min,初始浓度为200 mg/L时的吸附量为58.89 mg/g;氯苯酚的吸附平衡时间为90 min,初始浓度为300 mg/L时的吸附量为84.32 mg/g。煤质炭对苯酚的吸附过程与Langmuir吸附等温线,氯苯酚的吸附过程与Temkin吸附等温线拟合得较好。二级动力学模型能够较好地描述这2个吸附过程,且颗粒内扩散不是唯一的速率控制步骤。     

改性蔗渣焚烧灰去除糖蜜酒精废液中硫酸根

以改性蔗渣灰（MBA）为吸附剂,通过单因素实验,等温吸附模型拟合实验和正交实验,探讨了MBA去除糖蜜酒精废液的高浓度硫酸根离子的实验条件。结果表明,当MBA粒径60目,投加量为3 g·（25 mL）-1,反应温度45℃,pH为4.2,反应时间50 min时,溶液中的硫酸盐去除效果最优。等温吸附模型拟合结果表明,Langmuir模型更适合拟合该过程,MBA去除硫酸根离的反应为单分子层吸附。正交实验次优反应条件可以确定为：废液浓度为稀释15倍,MBA投加量3.0 g·（25 mL）-1,MBA粒径80目,反应时间1 h,反应温度为35℃。经验证,硫酸根离子的去除率达到88.86%。     

分布式认知理论框架下农户土地转出意愿影响因素研究——基于SEM模型的武汉城市圈典型地区实证分析

基于分布式认知理论,从"个人力"、"地域力"、"文化力"三个层次构建农户土地流转认知的影响因素理论框架,利用"武汉城市圈"典型地区土地流转调查数据构建结构方程模型(Structural Equation Model,SEM),定量分析各影响因素在农户土地流转认知中的作用。研究证实:不同农户认知群体之间存在不同流转认知偏好,"无文化的老农民"相对于"有文化的年轻职业者"在土地流转认知中更加保守;农户对土地的需求普遍偏向土地的资产属性和财产权利,农村土地流转具备内在动力;然而,出于对土地社会保障功能的需求,农户不会因为其家庭生产方式和经济来源明显脱离土地而产生强烈的土地转出愿意,农户的家庭生计条件及"土地情节"在一定程度上制约了土地流转;村镇干部"取信于民"是农户获得"安全感",克服风险规避心理促进土地流转认知的最重要因素;流转价格是对农户在土地流转中物质与精神"双重损失"的资金补偿,两者的匹配程度对农户的认知具有重要作用。在此基础上,得出要规范流转程序、健全流转监督机制、保护农民利益,加强农村社会保障制度建设以确保农民获得公平的社会保障,加快推进和支持农村教育以提高农村劳动力素质,建立和完善土地流转制度保障和农业经营扶持机制等政策启示。     

Comparative study on consumption behaviors in private car markets between large and medium–small cities in China

With the economic development and the acceleration of motorization in China, the number of private cars increases rapidly in urban areas. However, the limit of urban resources and the contradiction between traffic supply and demand are increasingly prominent in large cities, while private car consumption has been a new “light” in medium and small cities. Consumers’ behaviors differ from region to region. Aiming at the above problems, we formulate structural equation modeling and carry out empirical research. In this paper, a comparative study about the main influential factors that affect the consumption of private cars in large and small cities in China is made, and it is hoped that some guidance for policy recommendations can be obtained.