复合垂直流人工湿地的脱氮机理及影响因素分析

采用沸石和砾石作为填料,研究复合垂直流人工湿地处理农村生活污水的脱氮机理。试验结果表明:复合垂直流人工湿地对污水中氮的去除主要发生在下行流填料柱中,其去除机理主要是微生物对溶解态氮的硝化和反硝化作用;悬浮态氮沉积在填料孔隙中,会出现"氮释放"现象;水温、气水比、碳氮比、氮源形式等因素对湿地系统的脱氮效率有显著影响。     

Influence of Landscape Elements in Riparian Buffers on the Conservation of Semiaquatic Amphibians

Abstract:  Studies on riparian buffers have usually focused on the amount of land needed as habitat for the terrestrial life stages of semiaquatic species. Nevertheless, the landscape surrounding wetlands is also important for other key processes, such as dispersal and the dynamics of metapopulations. Multiple elements that influence these processes should therefore be considered in the delineation of buffers. We analyzed landscape elements (forest cover, density of roads, and hydrographic network) in concentric buffers to evaluate the scale at which they influence stream amphibians in 77 distinct landscapes. To evaluate whether our results could be generalized to other contexts, we determined whether they were consistent across the study areas. Amphibians required buffers of 100–400 m of suitable terrestrial habitat, but interspecific differences in the amount of habitat were large. The presence of amphibians was related to roads and the hydrographic network at larger spatial scales (300–1500 m), which suggests that wider buffers are needed with these elements. This pattern probably arose because these elements influence dispersal and metapopulation persistence, processes that occur at large spatial scales. Furthermore, in some cases, analyses performed on different sets of landscapes provided different results, which suggests caution should be used when conservation recommendations are applied to disparate areas. Establishment of riparian buffers should not be focused only on riparian habitat, but should take a landscape perspective because semiaquatic species use multiple elements for different functions. This approach can be complex because different landscape elements require different spatial extents. Nevertheless, a shift of attention toward the management of different elements at multiple spatial scales is necessary for the long-term persistence of populations.     

我国农村能源发展方针调整问题探讨

我国农村能源发展方针是“因地制宜,多能互补,综合利用,讲求效益”,这是在短缺经济的背景下,针对能源危机而提出来的。目前我国农村的社会、经济及其能源供需结构形势发生了重大变化,大量商品能进入农村市场,农村能源面临着结构升级和如何现代化的问题,原十六字方针因缺少生态观和市场观,已不符合现时和未来农村能源可持续发展的实际。文章提出了农村能源发展的十八字方针“因地制宜,生态兴能,市场调节,讲求综合效益”,并逐一对新方针中的论点进行了阐述,提出了我国应以生物质二次能源与商品能源整合的可持续能源的发展理念,提出了实施新方针的有关举措。     

新形势下河北省农村可再生能源管理与政策研究

我国农村可再生能源发展面临生态文明建设、能源安全趋紧、大气污染严重等新的形势变化。作为农业大省,河北省近年来农村可再生能源发展与管理成绩显著,为改善农民生活、保护生态环境、增加能源供应、促进经济社会发展等做出了积极贡献。但新形势下,其农村可再生能源管理也暴露出了思想认识不足、部分法规政策滞后、缺乏宏观科学规划、资金筹措机制单一、后续监督管理不够等问题,需要从加强宣传教育、提高认识水平,完善规章制度、形成法律体系,制定科学规划、明确目标计划,拓宽融资渠道、稳定资金支持、完善服务体系、加强后续管理等方面完善管理与政策,以推进其健康持续发展。     

陕西省淳化县农户生活垃圾处理方案的比选与分析

通过问卷调查和现场勘查对陕西省淳化县农村生活垃圾污染及处理现状进行分析,采用层次分析法对户用沼气池、户用堆肥池和小型焚烧炉3种主要处理方案进行经济效益、能源效益和资源环境效益的综合评价,结果表明户用沼气池的综合效益最高.选用成本效益分析、财务现金流分析和敏感度分析方法着重对户用沼气池推广的优势因素和限制因素进一步分析,结果表明,当农户有足够的资金、土地资本和垃圾产量时,应采用沼气池,同时应重视对沼气建设技术人员和维护管理沼气池农户的技术培训,以求保证建池质量;当农户资金、土地资本和垃圾产量有限时,也可以采用户用堆肥池,同时要注意堆肥池规格的设计,以求达到最高的综合效益.     

Suspended Particulate Matter Distribution in Rural-Industrial Satna and in Urban-Industrial South Delhi

An air quality sampling program was designed and implemented to collect the baseline concentrations of respirable suspended particulates (RSP = PM₁₀), non-respirable suspended particulates (NRSP) and fine suspended particulates (FSP = PM_2.5). Over a three-week period, a 24-h average concentrations were calculated from the samples collected at an industrial site in Southern Delhi and compared to datasets collected in Satna by Envirotech Limited, Okhla, Delhi in order to establish the characteristic difference in emission patterns. PM_2.5, PM₁₀, and total suspended particulates (TSP) concentrations at Satna were 20.5 ± 6.0, 102.1 ± 41.1, and 387.6 ± 222.4 μg m⁻³ and at Delhi were 126.7 ± 28.6, 268.6 ± 39.1, and 687.7 ± 117.4 μg m⁻³. Values at Delhi were well above the standard limit for 24-h PM_2.5 United States National Ambient Air Quality Standards (USNAAQS; 65 μg m⁻³), while values at Satna were under the standard limit. Results were compared with various worldwide studies. These comparisons suggest an immediate need for the promulgation of new PM_2.5 standards. The position of PM₁₀ in Delhi is drastic and needs an immediate attention. PM₁₀ levels at Delhi were also well above the standard limit for 24-h PM₁₀ National Ambient Air Quality Standards (NAAQS; 150 μg m⁻³), while levels at Satna remained under the standard limit. PM_2.5/PM₁₀ values were also calculated to determine PM_2.5 contribution. At Satna, PM_2.5 contribution to PM₁₀ was only 20% compared to 47% in Delhi. TSP values at Delhi were well above, while TSP values at Satna were under, the standard limit for 24-h TSP NAAQS (500 μg m⁻³). At Satna, the PM₁₀ contribution to TSP was only 26% compared to 39% in Delhi. The correlation between PM₁₀, PM_2.5, and TSP were also calculated in order to gain an insight to their sources. Both in Satna and in Delhi, none of the sources was dominant a varied pattern of emissions was obtained, showing the presence of heterogeneous emission density and that nonrespirable suspended particulate (NRSP) formed the greatest part of the particulate load.     

论可持续发展视野中的农村社会支持

本文阐述了如何可持续发展观来指导农村社会支持,并提出在农村社会支持活动中,引进社会保险、社会服务、生态保护和心理培育等新的机制,运用综合性评价指标体系对各种农村社会支持项目及其结果进行经济效益、社会效益和心理效益三个方面的分析。     

湖北农村降水中SO_4~(2-)浓度变化研究

在湖北农村 10个地点 ,利用澳大利亚集雨器自 1996年 1月至 1998年 6月 ,按季度采集大气降水样品测定SO2 - 4浓度 ,并对数据进行统计分析。研究结果表明 ,各地 1997年降水中SO2 - 4浓度年均值比 1996年显著升高 ;大多数地点 1996、1997、1998年 1季度和 2季度降水中SO2 - 4浓度呈逐年升高趋势 ;大多数地点每年 1、4季度降水中SO2 - 4浓度高 ,2、3季度降水中SO2 - 4浓度低 ,说明湖北农村降水中的硫对秋冬作物影响比对春夏作物影响大 ;湖北农村降水中SO2 - 4浓度近两年不仅有时间变化规律 ,而且同一季度内的地区差异也很明显 ,在 1996年和 1997年 8个季度 10个点的降水SO2 - 4浓度最大值中 ,有 4个最大值出现在襄樊 ,它是目前湖北继宜昌市区、恩施市区之后又一个酸雨发展较快的地区     

高架路桥的震害、震害原因及抗震措施

对近年来美、日等国的高架道路和高架桥梁所遭受到的地震破坏以及破坏原因进行了概述,对其在高架路桥的规划、设计、施工过程中所要取的抗震措施作了介绍。     

农村家庭认知与响应地震灾害的特点及其家庭际差异——以2007年云南宁洱6.4级地震灾区为例

以2007年云南宁洱6.4级地震灾区为例,通过现场访谈和问卷调查,分析了该地区农村家庭认知与响应地震灾害的特点及其家庭际的差异性。结果表明:当地农村家庭认知与响应地震灾害的水平尚不理想,综合防震减灾能力较弱;家庭对地震灾害知识和防震减灾技能的掌握程度,显著地影响着其在震时及震后的响应行为和态度,其中防震减灾技能的影响更显著;经济收入和教育背景不同的家庭,其地震灾害的认知水平和响应能力也呈现出明显的差异性,其中受教育程度的影响更明显,且可能是最根本的影响因素;家庭人口总数与家庭地震灾害认知与响应的综合能力呈显著的负相关关系,但这种影响也叠加了家庭经济文化因素的影响;对研究区而言,加强防震减灾实用技能和震时如何有效应对地震影响方面的教育,具有更重要的现实意义。