水雾荷电振弦纤维栅除尘器除尘性能影响因素的实验研究

为研究除尘系统结构最优配置,实验采用新型高效水雾荷电振弦栅除尘方法,以除尘效率及阻力损失为参照结果,选定纤维栅板数量、纤维栅与喷嘴间距、纤维栅材料和间隙4个因素进行单因素试验,针对各因素对纤维栅除尘效率的影响进行了分析研究,结果表明多块纤维栅除尘效果明显优于单块纤维栅,正常处理风速时3块纤维栅的除尘效率最高,纤维栅阻力与其数量呈正比;纤维栅除尘效率随间距增大而先增后减,间距为230 mm时除尘效率最高;塑胶纤维栅除尘效果明显优于其他材料,各阻力值排序为:塑胶＞涤纶＞不锈钢＞尼龙;纤维栅除尘效率随纤维间隙增大而降低,其阻力随间隙增大而减小;利用SPSS软件进行4因素三水平正交试验分析,在特定条件下除尘效率显著性排序为:纤维栅数=纤维栅间隙＞纤维材料＞纤维栅与喷嘴间距;阻力损失显著性排序为:纤维栅数=纤维栅间隙=纤维材料=纤维栅与喷嘴间距;试验最佳配置为3块间隙0.6 mm尼龙纤维栅板,且纤维栅板距喷嘴最小间距为185 mm。     

Valuing health effects from the industrial air pollution in rural Tianjin, China

IntroductionAirpollutioninTianjinisveryserious ,andismainlycausedbycoalconsumption .Theaverageconcentrationoftotalsuspendedparticulates (TSP)hasreached 0 3 5mg m3from 1990to 1998,exceedingChina’slevelⅡEnvironmentalCriterion ,whichis 0 2 0mg m3 Townshi…     

基于价值损失的黄河三角洲湿地生态补偿标准研究

生态补偿作为一种新型的资源与环境管理手段,越来越受到国内外学者的关注。在过去20年里,国内外学者对生态补偿的概念、机制、模式、标准及生态补偿的效益等做了大量研究,但由于生态补偿具有很强的学科交叉性和地域差异性,致使上述研究尚存在较大分歧。生态补偿标准关系到生态补偿的可行性及效果,因此是生态补偿研究的核心,但目前还没有公认的量化方法。本文以黄河三角洲湿地为研究对象,探讨了依据生态价值损失来制定生态补偿标准的途径。文章首先运用市场价值法、环境保护投入费用评价法、生态价值法、成果参数法等计算了黄河三角洲因湿地面积减少和环境污染造成的直接市场价值和生态服务功能价值的损失量,然后以生态价值损失量为依据制定了湿地生态补偿的资金分配方案和补偿标准。研究结果表明,不同湿地类型的补偿标准不同。对于同一湿地类型,以生态功能价值损失为依据制定的补偿标准远高于以市场价值损失为依据制定的补偿标准。本研究为黄河三角洲地区实施湿地生态补偿提供了重要科学依据。     

中国荒漠化灾害评估及其经济价值核算

本文对我国荒漠化的现状和危害进行了系统分析。运用货币估值方法对最新公布的荒漠化和水土流失监测数据进行计算，得出我国荒漠化危害的直接经济损失约642亿元/年，平均每天损失1.76亿元；其中几种主要荒漠化类型造成的经济损失分别为：水力侵蚀400亿元，风力侵蚀36亿元，盐渍化及有机质丢失造成的损失约186亿元；据估算每年因沙尘暴造成的经济损失超过13亿元，荒漠化及其衍生危害造成的间接经济损失约2889亿元/年。     

Value of Small Patches in the Conservation of Plant-Species Diversity in Highly Fragmented Rainforest

Abstract:  We evaluated the importance of small (<5 ha) forest patches for the conservation of regional plant diversity in the tropical rainforest of Los Tuxtlas, Mexico. We analyzed the density of plant species (number of species per 0.1 ha) in 45 forest patches of different sizes (1–700 ha) in 3 landscapes with different deforestation levels (4, 11, and 24% forest cover). Most of the 364 species sampled (360 species, 99%) were native to the region, and only 4 (1%) were human-introduced species. Species density in the smallest patches was high and variable; the highest (84 species) and lowest (23 species) number of species were recorded in patches of up to 1.8 ha. Despite the small size of these patches, they contained diverse communities of native plants, including endangered and economically important species. The relationship between species density and area was significantly different among the landscapes, with a significant positive slope only in the landscape with the highest deforestation level. This indicates that species density in a patch of a given size may vary among landscapes that have different deforestation levels. Therefore, the conservation value of a patch depends on the total forest cover remaining in the landscape. Our findings revealed, however, that a great portion of regional plant diversity was located in very small forest patches (<5 ha), most of the species were restricted to only a few patches (41% of the species sampled were distributed in only 1–2 patches, and almost 70% were distributed in 5 patches) and each landscape conserved a unique plant assemblage. The conservation and restoration of small patches is therefore necessary to effectively preserve the plant diversity of this strongly deforested and unique Neotropical region.     

昆明市水源区不同利用类型坡地径流氮和磷的输出特征

采用径流小区法对昆明市松华坝水源区牧羊河中游5种不同利用类型坡地2007年雨季地表径流氮和磷的输出情况进行观测分析.结果表明,随着雨季降雨次数的增加,径流小区产生的水样中,输出的ρ(TN)和ρ(TP)逐渐下降,在7月3日—9月17日的7次采样中,裸地、黄豆地、林地、土豆地和草地径流输出的ρ(TN)分别下降83.2%,79.8%,78.4%,75.9%和75.3%;输出的ρ(TP)分别下降74.6%,62.2%,54.2%,75.3%和72.1%,由此说明氮和磷的输出与地表径流及土壤侵蚀具有一致性.在氮和磷的输出过程中,强降雨对输出影响较大,施肥对输出影响明显.输出的可溶态氮素主要以NO₃--N为主.      

An Index of Risk as a Measure of Biodiversity Conservation Achieved through Land Reform

Abstract:  We measured the net progress of land reform in achieving a national policy goal for biodiversity conservation in the context of ongoing clearing of native vegetation and additions of land to a highly nonrepresentative (residual) reserve network, interior South Island, New Zealand. We used systematic conservation-planning approaches to develop a spatially explicit index of risk of biodiversity loss (RBL). The index incorporated information from national data sets that describe New Zealand's remaining indigenous land cover, legal protection, and land environments and modeled risk to biodiversity on the basis of stated assumptions about the effects of past habitat loss and legal protection. The index identified irreplaceable and vulnerable native habitats in lowland environments as the most at risk of biodiversity loss, and risk was correlated with the density of threatened plant records. To measure achievement, we used changes in the index that reflected gains made and opportunity costs incurred by legal protection and privatization. Application of the index to measure the difference made by land reform showed it had caused a net increase in the risk of biodiversity loss because most land vulnerable to habitat modification and rich in threatened plant species was privatized and land at least risk of biodiversity loss was protected. The application revealed that new high-elevation reserves did little to mitigate biodiversity decline, that privatization of low-elevation land further jeopardized the most vulnerable biodiversity in lowland native habitats, and that outcomes of land reform for biodiversity deteriorated over time. Further development of robust achievement measures is needed to encourage more accountable biodiversity conservation decisions.     

不同纤维素降解菌对玉米秸秆的降解效果

该研究旨在探索不同纤维素降解菌对玉米秸秆降解效果的差异性,为秸秆资源化利用提供参考。利用筛选自宁夏秸秆堆、畜粪和土壤中的四株纤维素降解菌,分别为黄曲霉(Aspergillusflavus)Z5-3菌株,非洲哈茨木霉(Trichoderma afroharzianum)Z6-4菌株,藤黄单胞菌(Luteimonas sp.)X11-1菌株,施氏假单胞菌(Pseudomonas stutzeri)X3-5-1菌株,通过室内控温秸秆堆肥发酵试验,研究添加不同纤维素降解菌后堆肥温度、pH值、碳损失、氮损失、有效养分含量的变化规律。试验结果表明,与对照(不加菌处理)比较,加菌处理提前1-2 d进入高温期,最高温度提高了0.3-1.3℃,且细菌处理较真菌处理提前1 d进入高温期,最高温度提高了0.5-0.7℃。pH值总体呈先增加后降低的趋势,且在高温期达到最大值。与对照相比,加菌处理NH3和CO2累积释放量具有降低趋势。以全氮含量变化计,细菌X11-1、X3-5-1处理的氮损失分别为26.14%和26.57%,真菌Z5-3、Z6-4处理分别为36.49%和34.19%,表明添加不同纤维素降解菌可不同程度地降低堆肥物料中的碳损失和氮损失,其中细菌处理保氮效果显著优于真菌处理。与对照相比,细菌X11-1、X3-5-1处理、真菌Z5-3、Z6-4处理分别提前腐熟5、2、2、2d,表明添加纤维素降解菌可减少堆肥物腐熟时间,促进物料养分浓缩。综合判断,玉米秸秆堆肥中加入纤维素降解菌,有利于降低物料的碳、氮损失,且细菌的保氮效果优于真菌,其藤黄单胞菌X11-1处理最先达到腐熟,为最佳处理。     

不同调理剂对微生物降解餐厨垃圾的影响

为了探索不同调理剂对微生物降解餐厨垃圾效果的影响,本实验选取了木屑(桦木)、米糠、泥炭、花生壳、稻壳等材料分别作为主要调理剂,以餐厨垃圾的重量减量率作为评价降解效果指标,测定实验过程中的温度、含水率、pH值、微生物生物量及重量的变化。实验结果表明,影响餐厨垃圾降解效果主要因素有温度和含水率;以木屑和米糠为主要调理剂的保温性能最优,其余材料热量散失较快;以50%木屑处理的调理剂含水率适宜,能达到最适含水率要求(50%);同时,以50%木屑(桦木)为主要调理剂处理的减量率最高。     

孔径对微孔曝气充氧性能的影响

孔径是微孔曝气产品最重要的参数之一,研究孔径对微孔曝气氧传质的影响对于提高微孔曝气器充氧性能有重要意义。本研究在1.5 m水深条件下对不同大小孔径的钟罩型塑料微孔曝气器充氧性能进行评价。结果发现,在实验条件下,微孔曝气器的阻力损失RL、标准氧总转移系数KLas、标准氧转移速率SOTR,标准氧转移效率SOTE及理论动力效率E随孔径增大而显著减小。