脉冲调制介质阻挡放电和催化联用技术降解甲苯

利用低温等离子体处理挥发性有机化合物(VOCs)废气是目前国内外研究的热点。研究利用脉冲调制介质阻挡放电和催化联用技术降解甲苯,对比分析了连续放电和脉冲调制对去除甲苯的影响;研究了脉冲调制后在有无催化剂的情况下的能量效率,比较了两种情况下的臭氧浓度以及中间产物的不同。结果表明:脉冲调制有效提高了甲苯的降解能效,其能量效率几乎是连续放电时的2倍～3倍;在有催化剂的情况下,能量效率是没催化剂的1.5倍～2倍,臭氧浓度明显降低,结焦产物中含苯环的衍生物的量少于无催化的结焦产物。     

臭氧接触池臭氧投加方式的优化

臭氧接触池内臭氧(O₃)投加方式是影响臭氧接触池反应效率的关键因素. 以密云水库水为处理对象,对臭氧接触池内臭氧投加方式进行优化,通过考察气液接触方式和投加点个数对ρ(O₃)、传质效率及有机物去除率的影响,确定最优臭氧投加方式. 结果表明,适当增加布气点个数可有效增强气液传质,提高有机物去除率,但当布气点个数高于3个时,臭氧传质效率无明显提升,而且造成出水ρ(O₃)过高,不利于后续工艺的进行. 采用三段式臭氧投加方式,臭氧投加比为3∶3∶1时,密云水库水中臭氧传质效率达78.1%,有机物去除率为47.5%; 向密云水库水中添加3mg/L腐殖酸后,该投加比下臭氧传质效率为76.8%,有机物去除率为40.3%,出水ρ(O₃)为0.26mg/L,不会对后续工艺产生影响;并且该条件下臭氧利用率最高,BrO₃-生成量最低,为最佳臭氧投加比.      

Perceptions of the local community on the outcome of community fishery management in Krala Peah village,Cambodia

Since fishery resources are regarded as an important source of income and food security, these resources need to be protected and conserved for sustainable use. To do this, the government of Cambodia has revised its policies, shifting management and responsibility to the local level. In response to government policy, Krala Peah village community fishery was established to manage resources within the area. The purpose of this study was to assess the outcome of community fishery management. Moreover, community fishery management was assessed through face-to-face interview and a participatory approach. The major findings of this study indicate that community fishery has led to a more equitable and efficient fishery within Krala Peah village. Although it has not led to improvements in fishing habitats and fish catch, it has reduced some factors that adversely affected sustainability. Furthermore, it has caused a reduction in illegal fishing, which was the main objective of the fishers.     

Incorporating greenhouse gas effects to evaluate energy efficiency in China

Reducing greenhouse gas emissions without hampering economic growth is a significant issue for China. Taking into account environmental sustainability principles, this study analysed the energy efficiency of 30 regions of China for the period 2002–2007. By employing a data envelopment analysis (DEA) approach, this study included undesirable CO₂ and SO₂ outputs and the desirable GDP output in the model. Empirical outcomes demonstrated that the overall average technical efficiency (TE) of China is 0.843, indicating a 15.70% input inefficiency. Among three geographic areas, the east has the highest technical efficiency, with the highest ability to set up clean-burning power plants based on best technology available. Performance in the west is less good because of much inefficient technology. Finally, the study demonstrates detailed management implications of the BCG matrix. The most important contribution of this paper is a detailed demonstration of an energy performance evaluation mechanism for China. The valuable results and insights gained can be equally effectively applied to studies in other developing countries facing the same gaseous emissions.     

On equilibrium in resource markets with scale economies and stochastic prices

In this paper, I show the existence and the characteristics of equilibrium in a non-renewable resource market where extraction costs are non-convex and market price is subject to stochastic shocks, an empirically relevant setting. In my model firms may be motivated to hold inventories to facilitate production smoothing, which allows them to continue producing at a smooth pace at any instant when extraction ceases, e.g. when reserves are exhausted. This aspect of the model then supports a competitive equilibrium in the presence of non-convex costs. Casual empirical evidence is provided that supports the central features of my model for a variety of non-renewable resources, lending credence to the explanation for equilibrium I propose.     

Fenton法对合成制药废水的预处理试验研究

采用Fenton法对某合成制药废水进行了预处理试验研究,考察H2O2、Fe2+投加量及反应时间对废水CODCr、色度、NH4+-N去除效果的影响,重点分析了反应体系中有毒难降解有机污染物的变化情况。结果表明,当H2O2(30%)投加量为2%(体积分数),FeSO4.7H2O投加量为400mg/L,反应时间为60min时,废水CODCr、色度的去除率分别为67.73%和40.05%。通过GC-MS分析发现,该废水中含有多种脂类和苯环类等难降解有机污染物质,Fenton反应过程中出现了醇、酯、有机酸等较易降解的中间产物,随着反应的进行废水中苯环类、脂类等大分子有毒有机物得到大幅削减,废水的生物毒性大大降低,BOD/COD值由0.18上升至0.48,可生化性明显提高。     

中国煤炭企业安全效率及其影响因素分析

为准确评价中国煤炭企业安全效率,基于数据包络分析(DEA),对2009年中国煤炭企业100强中的30家企业的安全整体效率(TE)、纯技术效率(PTE)和规模效率(SE)进行实证分析;在此基础上,运用Tobit模型探讨影响煤炭企业安全TE的因素。研究结果显示,煤炭企业安全投入、整体科研能力与安全效率成正相关;厂商规模、劳动生产率与安全效率成显著正相关。基于此,从4个方面给出提高煤炭企业安全效率的建议。     

我国地铁运营公共现场安全防范效率研究

城市化进程的加速导致了人口、交通和环境的日益恶化,有限的地上空间资源即使过度开发也不堪重负,使得人们转而求诸于地下空间的利用,地铁因其安全、准时、高效等特点成为解决地上交通矛盾的有效手段,也成为目前地下空间应用的重要领域.地铁自问世以来,其安全问题一直如影随形、备受瞩目,随着建设规模的不断扩大,基于效率的降低成本与基于安全的加大投入之间产生了巨大的矛盾分歧.依托安全经济学和投入产出理论提出安全效率的概念界定及表达框架,并选取地铁楼梯进行案例分析,验证其可行性和可计量性.该量化模型的提出有助于在同时考虑安全与效率时提供决策参考,从而指导项目安全投入的合理配置,提高资金的使用效率.     

几种春季湿地植物对污水中主要污染物去除效果的比较

研究了菖蒲、香蒲、美人蕉和芦苇四种在南京地区春季常见的人工湿地植物对生活污水中主要污染物的处理能力，试验周期为1个月。试验数据表明，在春季，南京地区的菖蒲、香蒲和芦苇长势良好，而美人蕉生长缓慢。与之相对应，菖蒲和香蒲的处理能力较好，其对TN、TP和COD的去除率分别达到了72．46％、90．36％、65．05％和69．82％、91．32％、77．15％；芦苇的处理效果略次于菖蒲和香蒲，其TN、TP和COD的去除率分别为58．84％、74．60％和57．19％，而美人蕉的处理效果较差。通过分析，认为菖蒲和香蒲是春季湿地植物的理想选择，美人蕉不适合作为春季湿地植物使用。     

A resource-based approach to modelling the dynamics of interacting populations

The procedure for modelling the growth of single-species populations [Sakanoue, S., 2007. Extended logistic model for growth of single-species populations. Ecol. Model. 205, 159–168] is improved to be applicable to the study of the dynamics of interacting populations. The improved procedure is based on three assumptions: resource availability changes with population size as a variable, resource supply to populations and population demand for resources are defined as functions of resource availability and population size, and the variables of resource availability and population size shift in the supply function attracted to the demand function. These assumptions are organized into three equations. The equations can generate the dynamics models of plant, herbivore, and detritivore populations, and their own resources. The models can be used to describe prey–predator dynamics. They naturally contain nonlinear terms for the predator’s numerical and functional responses. Depending on the terms, the fluctuations in resource availability and population size stabilize. The three equations can also generate the dynamics models of different populations consuming the same resources. The analysis of zero isoclines of the models shows that a superior population can be simply defined as one with a higher intrinsic rate of natural increase, that a stable coexistence may be realized with the intraspecific interference or the interspecific facilitation of superiors, and that the interspecific interference or the intraspecific facilitation of inferiors may make the coexistence unstable and the inferiors winners depending on their initial population size.