荧光素酶报告基因法测定废气中二英类物质

研究二噁英类生物检测法的主要目的是简化二噁英类分析流程,并找出快速检测的结果与HRGC-HRMS(高分辨气相色谱-高分辨质谱)结果之间的换算系数,从而可以利用快速检测的结果和换算系数来推算HRGC-HRMS的结果. 介绍了CALUX(荧光素酶报告基因法)分析废气中二噁英类物质的原理,并采用该方法分析了我国27个废气样品,以期找出其测定结果与HRGC-HRMS结果之间的换算系数. 结果表明,这2种测试方法数据相关性显著,R2为0.994 8,数据间的换算系数为0.379. 试验表明,CALUX法具有很好的推广性,如果再适当增加废气样品的数量,对换算系数进行适当的优化,则所得换算系数可推广.      

钙基CO_2吸收剂循环特性影响因素分析

利用小型固定床反应器研究了循环煅烧/碳酸化过程中,煅烧温度、煅烧气氛、碳酸化温度、压力等对钙基CO2吸收剂循环特性的影响,确定了影响钙基CO2吸收剂循环特性的主要因素。结果表明:随循环次数的增加,吸收剂的转化率明显下降,循环10次后,其基本都下降到20%左右;煅烧温度是影响吸收剂循环特性最重要的因素;煅烧气氛中存在CO2对吸收剂活性保持不利;吸收压力和温度也对吸收剂的循环特性有一定影响,较高的吸收压力和吸收温度有利于吸收剂转化。     

Multi-objective Programming and Social Welfare Analysis of Rural–urban Land Conversion Decision-making

Abstract

Rural–urban land conversion is an inevitable phenomenon in urbanization and industrialization. And the decision-making issue about this conversion is multi-objective because the social decision maker (the whole of central government and local authority) has to integrate the requirements of different interest groups (rural collective economic organizations, peasants, urban land users and the ones affected indirectly) and harmonize the sub-objects (economic, social and ecological outcomes) of this land allocation process. This paper established a multi-objective programming model for rural–urban land conversion decision-making and made some social welfare analysis correspondingly. Result shows that the general object of rural–urban land conversion decision-making is to reach the optimal level of social welfare in a certain state of resources allocation, while the preference of social decision makers and the value judgment of interest groups are two crucial factors which determine the realization of the rural–urban land conversion decision-making objects.     

Evaluating China's Slope Land Conversion Program as sustainable management in Tianquan and Wuqi Counties

Increased soil erosion on sloped land has become a significant environmental concern in China that has been attributed to human activities such as deforestation, over-cultivation, and over-grazing of livestock. In order to reduce soil erosion on sloped lands, the Chinese government has responded by implementing large-scale, ecological rehabilitation programs, including the "Grain for Green" reforestation project. This program involves financial incentives to transition farmers into other economic activities with the goal of reducing ecological pressures and degradation. Because of the scope and potential impacts from these programs, detailed research is needed to understand their social and ecological effects. This paper reports on research conducted in Tianquan County, Sichuan Province, and Wuqi County, Shaanxi Province, that evaluates the effects of the program upon local economies and household livelihood systems. The paper argues that the successful conversion of farmland under "Grain for Green" depends upon local government involvement, local economic development, and funding for local projects. Without economic development within rural economies, we conclude that farmers will remain dependent upon continued subsidy assistance to meet the policy's ambitious environmental restrictions, thereby undermining the program's long-term sustainability.     

曝气复氧对底泥氮素生物地球化学循环影响的作用机制研究

通过分析底泥氮污染物释放规律和转化过程,以及底泥生境、氮形态变化和氮循环功能微生物群落结构变化的规律,探讨了不同曝气复氧条件影响底泥氮生物地球化学循环的生物代谢、物理化学联合作用的机制。结果表明：曝气复氧对底泥中氮的生物地球化学循环影响是一个包括微生物代谢作用和物理化学作用的复杂联合作用过程。水体好氧环境的改变主要引起参与底泥氮循环的硝化、亚硝化和反硝化功能菌群群落结构的演变,对异养菌和氨化菌的影响不大,证明环境好氧条件的改变对底泥有机质生物分解产生氨氮的微生物代谢过程影响不大,主要对底泥释放的氨氮硝化、反硝化等生物转化过程产生大的影响。不同溶解氧条件下,底泥释放的氮素在微生物作用下主要以NH4＋-N和NO3--N的形式进入试验体系,并在特定的氧化还原电位（临界值-200 mV）和pH（临界值6.70）条件下通过物理化学作用在底泥中以离子交换态氮（IEF-N）、碳酸盐结合态氮（CF-N）、铁锰氧化态氮（IMOF-N）及有机态和硫化物结合态氮（OSF-N）等不同形态氮相互转化,同时,在氮的转化和循环过程中部分输入上覆水体。在低溶解氧组实验条件下[ρ（DO）〈0.5 mg.L-1],底泥向水体输出氮总量为底泥可转化态氮的19.7%,主要为氨氮,最大释放速率达到289.13 mg.m-2.d-1,释放的质量浓度可达到18.8 mg.L-1;好氧条件下（DO饱和）,底泥向水体输出氮总量为底泥可转化态氮的1.8%;好氧-缺氧条件下为11.7%,主要以N2的形式释出系统。     

我国厨余垃圾资源化技术的多维绩效评价

随着我国大力推动生活垃圾分类管理工作,厨余垃圾的资源化利用受到越来越多关注.厨余垃圾资源化技术已有包括厌氧消化处理、好氧生物处理和昆虫饲料转化等类型,但在已有应用案例中存在资源化程度低、环境影响显著和经济效益差等诸多问题,缺乏技术绩效的系统化分析和综合性评价.为此,研究面向厨余垃圾资源化技术应用的全生命周期过程,构建了资源效率、环境影响、经济可行和社会效应的多维绩效评价指标体系(包括21项指标),以我国的14项典型技术应用项目为案例开展定量化综合评价研究.结果表明,厌氧消化和昆虫饲料转化处理技术的得分分别为58.39分和59.65分,高于好氧生物处理(49.16分);按细分技术类型,集中式黑水虻转化和中温湿式厌氧工艺得分较高,分别为67.14分和60.82分.按技术的处理规模和设施分布方式,集中式处理技术在资源效率和经济效益维度上分别比分散式技术高出13%和62%;分散式处理技术在环境影响和社会效应维度上比集中式高出8%和34%.在厨余垃圾资源化实践中,应结合当地的厨余垃圾理化性质、生活垃圾分类收集工作推进情况、财政承担能力和收运距离等多因素综合考量,因地制宜的选择适宜技术路线.     

南京城市大气氨-铵的高频演化及其气粒转化机制

本研究于2018年秋季利用在线气体和气溶胶组分监测仪以高时间分辨率连续测定南京市大气中的气体(主要是NH_3)与二次无机气溶胶(主要是NH_4~+、NO_3~-和SO_4~(2-))浓度,借此研究污染和非污染期城市大气NH_3和NH_4~+的演化规律,进而探讨NH_3-NH_4~+气粒转化过程中的化学机制.结果表明,观测期间NH_3和NH_4~+浓度的平均值(±1σ)分别为(15. 3±6. 7)μg·m-3和(11. 3±7. 8)μg·m-3,且日变化在污染和非污染事件中呈现出显著的差异.综合在线观测的NH_3和NH_4~+浓度数据,通过计算潜在源贡献因子,分析了NH_3和NH_4~+的潜在贡献源区在重污染过程受长距离污染传输影响较小,证明城市也是NH_3排放的重要热点地区.进一步分析发现,NH_3-NH_4~+的气粒转化是影响NH_3和NH_4~+日变化的主要驱动因子.具体体现在:低温、高湿(温度在7. 5～12. 5℃,湿度在50%～90%)时,NH_3和NH_4~+的气固转化速度较快,NH_3与酸性物质反应生成更多的NH_4~+,使得(NH4)2SO4和NH4NO3的形成从而导致污染事件的加剧.研究结果有助于厘清城市大气NH_3的来源和转化机制及其对颗粒物的潜在贡献.     

双金属复合管线应力分析中当量折算模型的建立与应用*

针对目前高腐蚀性气田的集输系统管线应力分析标准中,未给出双金属复合管线的强度校核方法,依据当量折算理论,将双金属复合管的几何与材料特性转化为等效单层管,通过有限元法验证双层管与等效管模型的计算精度。研究结果表明:利用当量折算理论,可以快速将双金属管外径、壁厚、弹性模量、热膨胀系数、密度等参数等效转化为单层管道相关参数。经实际应用检验,该方法在解决工程问题时具备一定的实用性与准确性;双金属复合管系统当量折算模型具备计算方便和精度高等优点,该模型可用于双金属复合管线结构设计和强度校核。研究结果可为双金属复合管线的强度校核提供1种参考方法。     

Biofuel Plantations on Forested Lands: Double Jeopardy for Biodiversity and Climate

Abstract: The growing demand for biofuels is promoting the expansion of a number of agricultural commodities, including oil palm (Elaeis guineensis). Oil‐palm plantations cover over 13 million ha, primarily in Southeast Asia, where they have directly or indirectly replaced tropical rainforest. We explored the impact of the spread of oil‐palm plantations on greenhouse gas emission and biodiversity. We assessed changes in carbon stocks with changing land use and compared this with the amount of fossil‐fuel carbon emission avoided through its replacement by biofuel carbon. We estimated it would take between 75 and 93 years for the carbon emissions saved through use of biofuel to compensate for the carbon lost through forest conversion, depending on how the forest was cleared. If the original habitat was peatland, carbon balance would take more than 600 years. Conversely, planting oil palms on degraded grassland would lead to a net removal of carbon within 10 years. These estimates have associated uncertainty, but their magnitude and relative proportions seem credible. We carried out a meta‐analysis of published faunal studies that compared forest with oil palm. We found that plantations supported species‐poor communities containing few forest species. Because no published data on flora were available, we present results from our sampling of plants in oil palm and forest plots in Indonesia. Although the species richness of pteridophytes was higher in plantations, they held few forest species. Trees, lianas, epiphytic orchids, and indigenous palms were wholly absent from oil‐palm plantations. The majority of individual plants and animals in oil‐palm plantations belonged to a small number of generalist species of low conservation concern. As countries strive to meet obligations to reduce carbon emissions under one international agreement (Kyoto Protocol), they may not only fail to meet their obligations under another (Convention on Biological Diversity) but may actually hasten global climate change. Reducing deforestation is likely to represent a more effective climate‐change mitigation strategy than converting forest for biofuel production, and it may help nations meet their international commitments to reduce biodiversity loss.     

鄂尔多斯十大孔兑区植被生产力变化趋势对土地利用转移的响应

归一化植被指数(Normalized difference vegetation index,NDVI)是衡量区域植被生产力变化的一个重要指标,而土地利用/覆盖变化(Land use/cover change,LUCC)进程深刻影响了陆地生态系统空间分布格局及其生产力变化。因此本文结合趋势分析和转移矩阵法,从中分辨率成像光谱仪(Moderate-resolution Imaging Spectroradiometer,MODIS)NDVI年际变化角度分析鄂尔多斯北部典型农牧交错区(十大孔兑地区)2000-2015年植被生产力的变化趋势与LUCC的关系。结果表明:(1)在农牧交错区植被生产力总体呈增加趋势,其中显著增加和不显著增加区域面积占总面积的89.41%,分别为22.01%和67.4%;其后依次为不显著减少区域、无变化区域和显著减少区域,面积比例分别为4.59%、3.32%和2.68%。(2)在不显著增加和显著增加区,土地转换面积分别为235146.08 hm2和82761.76 hm2,草地转为农田、林地、水体、建设用地和未利用地尤其是草地转为农田导致对应区域植被生产力增加。