两株产电菌电子介体介导的胞外电子传递机理研究

构建了Klebsiella oxytoca d7和Shewanella sp.F1 2种纯菌燃料电池，探究了产电菌在产电过程中电子介体传递电子机制.结果表明：K.oxytoca d7只有作产电呼吸时，才会产生电子介体，而Shewanella. sp.F1在好氧呼吸、厌氧呼吸、产电呼吸下均能产生介电体，说明电子介体的产生与产电菌种类有关.两种菌介电体氧化还原电位相当（-250，210mV），且介于呼吸链NADH和辅酶Q之间.其介电体在胞内呼吸链上截获的电子均源于NADH，说明电子“逸出”位点只取决于介电体本身.K.oxytoca d7在碳源充足和不足时，电子介体产电量分别占总电量的60%和41%；Shewanella. sp.F1分别是57%和50%，说明在碳源充足时，2种菌的产电呼吸都以电子介体机制为主.介电体传递电子过程直接影响了阳极底物的转化和燃料电池的产电性能.     

非农就业与土地流转对农户耕地撂荒行为的影响——以闽赣湘山区为例

耕地撂荒是世界各国长期普遍存在的一种土地利用变化现象。基于闽赣湘山区640户农户调查数据,运用Tobit和IV-Tobit模型回归分析得出：农户家庭非农就业每提升10%,耕地撂荒占比会增加1.11%;小规模农户土地转入会提升其耕地撂荒规模,此时扩大经营规模对耕地撂荒的减缓作用甚微,而土地转出会降低非农就业对耕地撂荒的正向影响。此外,农户的劳动力、土地与农业机械等要素投入,以及灌溉条件和地块数等均稳健影响其耕地撂荒行为。农业机械化和土地流转是缓解山区耕地撂荒的重要举措,政府在推动经营规模扩大的同时,应着重提高地块规模,鼓励留村务农劳动力换工,并提升农机社会化服务水平,以及拓宽农户家庭多元化的收入机会。     

植物提取液对城市垃圾中转站恶臭物质的处理效果

对某2种商品植物除臭剂（代号A和C）进行了NH3和H2S的去除效果实验,确定了其最佳的使用条件;并实验了植物提取液对城市垃圾中转站渗滤液和实际中转站中恶臭气体的处理效果。结果显示,终浓度为0.85 g/m3的植物提取液A对NH3和H2S的去除率最高可达39.9%和92.31%;在城市垃圾中转站试验中,1.02 g/m3的植物提取液A结合超声波雾化装置对NH3和H2S的去除率可达66.67%和96.67%。研究表明利用植物提取液可以有效降低城市垃圾中转站恶臭污染物浓度,而采用超声波雾化装置效果更好。     

淮河流域旱涝易发区农田的陆气相互作用——CO_2通量、能量交换和水汽输送的季节变化特征

利用淮河流域旱涝易发区的安徽省寿县农田下垫面陆气相互作用观测试验资料,重点分析观测期内CO2通量、能量交换和水汽输送的季节变化,并讨论了与此有关的辐射分量通量、下垫面反射率、波恩比、能量闭合守恒、土壤温度和土壤湿度的季节变化。结果表明:CO2通量、能量分配受地表农作物长势影响明显,其中,水稻灌浆、成熟期,被稻田吸收的CO2通量最大可超过2 mg.m-2.s-1,潜热通量达到正的极大值。稻田光合作用最旺盛时期吸收的CO2通量和释放的潜热通量均大于小麦田光合作用最旺盛时期的对应量。较大土壤热通量对应于较低的土壤水含量。试验观测期的下垫面平均反射率为0.14。作物生长期,稻田表面潜热是下垫面吸收能量的主要消费者,小麦田表面潜热和感热相当。能量闭合率ε的变化范围为0.4~1。     

某耗能减震框肢剪力墙转换结构分析

采用复合型铅粘弹性阻尼器对带转换层框肢剪力墙结构的某酒店进行了耗能减震设计,对耗能减震结构和钢支撑结构进行了对比分析,包括反应谱和局部非线性多遇地震作用和罕遇地震作用下的时程分析。结果表明,底部框架结构布置复合型铅粘弹性阻尼器后,在多遇和罕遇地震情况下层间位移能满足《建筑抗震设计规范》要求,并且采用耗能减震结构能优化整体结构,不会对转换层上部结构产生不利的影响,能更好地改善结构的抗震性能。     

Influence of thermal radiation on layered dust explosions

Multidimensional unsteady numerical simulations were carried out to explore the influence of thermal radiation on the propagation and structure of layered coal dust explosions. The simulation solved the reactive compressible Navier-Stokes equations coupled to an Eulerian kinetic-theory-based granular multiphase model. The radiation heat transfer is modeled by solving the radiation transfer equation using the third-order filtered spherical harmonics approximation. The radiation was assumed to be gray and all boundaries of the domain are black at 300 K. The reaction mechanism is based on global irreversible reactions for each physical process including devolatilization, char burning, moisture vaporization, and methane combustion. The governing equations were solved using a high-order Godunov method. Several simulation configurations were considered: layer volume fractions of 47% and 1%, channel lengths of 10 m and 40 m, and radiative and non-radiative cases. The results show that gray radiation has a significant influence on the propagation and structure of a layered dust explosion. However, radiation can have opposite effects on different scenarios. For example, radiation promotes the propagation of the dust flame when the layer volume fraction was 1% and in the short-channel cases where reflected shock-flame interactions are important. However, radiation enhances quenching for the 47% volume fraction dust layer in the longer channel.     

Cash transfers' effect on government support: the case of Fiji

While some scholars have found that government post-disaster assistance supports the incumbent, others have shown that incumbent effects among beneficiaries are imperceptible or negative. This article contributes to this debate by using a regression discontinuity design of households affected by Tropical Cyclone Winston in Fiji to show that the type of assistance provided is an important variable in understanding the effects of aid on perceptions of the government. Residents of Fiji who received a post-disaster cash transfer are up to 20 per cent more likely to be very satisfied with the government than are those who did not. The probability further increases if the cash transfer was provided along with in-kind benefits or vouchers, but it is not affected if beneficiaries were also encouraged to use their own pension savings. This paper provides evidence in favour of the ‘attentive citizen’ theory by demonstrating that beneficiaries actively appraise government responses; it also reveals possible effects of elite capture on the relationship between the government and beneficiaries.     

自然资源代际转移模型研究

代际均衡发展是可持续发展的核心内容之一，而代际均衡的实现在目前情况下有赖于代际主动财富转移改策实施。政府的宏观调控是实施这一政策的有力手段。具体的措施可开征“资源代际补偿税”以建立专项基金制度     

Trophic state, ecosystem efficiency and biodiversity of transitional aquatic ecosystems: analysis of environmental quality based on different benthic indicators

Estuaries and coastal lagoons are characterized by a strong spatial and temporal variability of physicochemical characteristics and productivity patterns. In these environments, the magnitude and direction of the ecological responses to inorganic nutrient increase (i.e. eutrophication) are difficult to predict. In the framework of the project, New Indicators of Trophic state and environmental quality of marine coastal ecosystems and transitional environments (NITIDA), we analysed benthic indicators of trophic state, ecosystem efficiency, and environmental quality in four different transitional environments. The trophic state of the sediments was assessed in terms of quantity and bioavailability of sediment organic C pools; ecosystem efficiency was determined in terms of the prokaryote efficiency in exploiting enzymatycally degraded organic C; environmental quality was determined in terms of meiofaunal diversity. Here, we provide a synopsis of the results obtained and a meta-analysis of the scores assessments obtained using the different ecological indicators of environmental quality and demonstrate that trophic state, ecosystem efficiency, and biodiversity in transitional ecosystems are closely linked. We conclude that the assessment of the environmental quality of transitional ecosystems should be based upon a battery of trophic state indicators and 'sensors' of ecosystem functioning, efficiency, and quality.     

Auditing a flooded quarry prior to marina development

Development of a marina in a flooded brownstone quarry will require construction of a canal to the Connecticut River through an isthmus separating the two systems. An environmental audit over a 16-month period developed quantitative limnological data required by regulatory agencies. The deep quarry basin, protected by high sandstone walls, became strongly stratified in summer. Development of littoral vegetation in the quarry was prevented by the steep sides of the basin. Unusual characteristics of the manmade quarry basin, compared to most natural lakes in Connecticut, included a mean depth of 14 m, an intense thermocline, and negative heterograde oxygen profiles with metalimnetic minima. Alkalinity, conductivity, and nutrient levels differed significantly between the quarry and the river. Mean chlorophyll a concentrations in the two systems were similar, but the distribution of phytoplankton classes were quite different. The environmental audit, by comparing physical, chemical, and biological characteristics of the quarry to those of the river, allowed prediction of changes in trophic status when the two systems are joined.