人为干扰对小兴安岭森林湿地土壤碳组分和酶活性的影响

以小兴安岭落叶林沼泽湿地为研究对象,对比研究皆伐地、火烧地和落叶松湿地土壤碳组分和酶活性.结果表明:(1)3种湿地类型土壤SOC含量表现为对照地显著高于皆伐地和火烧地(p0.05),在0~10 cm土层中皆伐地与对照地相比降低了58.38%,火烧地与对照地相比降低了61.96%.皆伐地与火烧地在不同土层的土壤中SOC含量差异不显著(p0.05);DOC含量对照地显著高于皆伐地和火烧地(p0.05).在0~10cm土层中火烧地DOC含量是皆伐地的1.99倍,两者差异不显著(p0.05);不同干扰方式对土壤MBC含量影响的差异主要表现在0~10 cm的土层土壤,对照地分别比皆伐地和火烧地高23.13%和95.79%(p0.05).在不同的土层中皆伐地MBC含量均大于火烧地,与SOC含量的变化趋势一致.(2)与对照地相比,皆伐地与火烧地0~10 cm土层的土壤蔗糖酶活性分别降低了45.59%和36.76%,脲酶活性显著降低了18.22%和55.69%(p0.05),蛋白酶活性降低了19.65%和17.34%,淀粉酶活性降低了6.29%和10.69%.土壤碳组分和酶活性在垂直方向上均表现为随着土层深度增加而减小.皆伐和火烧造成森林湿地土壤碳组分和酶活性降低.     

西安市建筑垃圾渣土资源再利用研究

建筑垃圾渣土作为"建筑副产品",已造成严重的城市环境问题。通过对西安市建筑垃圾渣土的现场调查及工程再利用,借鉴发达国家及国内省市建筑垃圾渣土的成功管理经验和资源再利用的成功范例,提出了西安建筑垃圾资源再利用的对策建议,对"十三五"期间减少已有建筑垃圾的存量并遏制增量和建设西安森林城市具有参考意义。     

西安市PM2.5燃煤源谱特征研究

针对西安本地源谱缺乏的现状,总结统计了西安目前灰霾特征和主要成因,对西安市燃煤源进行了测定.研究发现,在煤烟尘PM2.5中SO2-4的含量最高(25%),其次为OC(12%)、NH+4(7%)、Cl-(5%).对固定源燃煤与民用散烧煤,不同脱硫方式、脱硝方式和锅炉类型的固定源成分谱分析得出:1.SO2-4及Al、Si、Ca在固定源煤烟尘PM2.5中含量大于民用燃煤,OC与之相反;2.炉内喷钙法PM2.5中SO2-4明显高于其它脱硫法含量;双碱法PM2.5中Na的含量显著高于其它脱硫工艺流程的含量;氧化镁法PM2.5 中Mg含量为各类脱硫工艺中最高;石灰石膏法颗粒物中Mg、Al、Si、Ca等元素含量均高于大多数工艺;3.不同的脱硝工艺中NO-3离子在各类成分谱中的含量极低;4.链条炉与层燃炉PM2.5中OC、EC含量高于循环流化床炉、煤粉炉.     

Further evidence of nuclear reactions in the Pd/D lattice: emission of charged particles

Almost two decades ago, Fleischmann and Pons reported excess enthalpy generation in the negatively polarized Pd/D-D₂O system, which they attributed to nuclear reactions. In the months and years that followed, other manifestations of nuclear activities in this system were observed, viz. tritium and helium production and transmutation of elements. In this report, we present additional evidence, namely, the emission of highly energetic charged particles emitted from the Pd/D electrode when this system is placed in either an external electrostatic or magnetostatic field. The density of tracks registered by a CR-39 detector was found to be of a magnitude that provides undisputable evidence of their nuclear origin. The experiments were reproducible. A model based upon electron capture is proposed to explain the reaction products observed in the Pd/D-D₂O system.

西安市人为源挥发性有机物排放清单及研究

对西安市各类VOCs人为源进行系统分类,收集活动水平数据,应用国内外排放因子研究的最新成果,采用排放因子法建立了西安市2014年人为源VOCs排放清单.结果表明:2014年西安市人为源大气VOCs排放量为11.51×104t,其中,固定燃烧源、生物质燃烧源、工艺过程源、有机溶剂使用源、移动源、油品存储与销售源和废弃物处理源的排放量分别占VOCs排放总量的2.53%、3.32%、13.30%、51.50%、23.64%、4.82%和1.02%.油墨印刷、建筑涂料和汽车喷涂为有机溶剂使用源重点排放行业,VOCs排放量占到排放总量的48.89%;工艺过程源中化学药品、医药制造、原油加工和化学纤维为重点排放行业,VOCs排放量占到排放总量的10.19%.各区县中,长安区、雁塔区、未央区、碑林区VOCs排放量明显较高,其分担率分别为16.53%、14.88%、14.47%和12.99%.     

我国人为源气态活性氮排放时空变动特征分析

随着粮食和能源需求的增加,农业生产和化石燃料燃烧带来的活性氮污染越来越成为影响我国环境和人民健康的重要因素之一.通过对2000、2005及2010年全国31个省(直辖市、自治区)的人为源气态活性氮排放总量、单位GDP及单位人均排放量的Moran's I指数和GetisOrd G*i指数进行空间分析,探讨了气态活性氮排放及其强度的时空变动特征.结果表明,全国的气态活性氮排放及其强度呈现明显的空间集聚特征.在空间分布特征上,全国活性氮排放表现为高值集聚分布,其热点主要位于华北平原和长江中下游平原地区;排放强度方面则为高值聚集和低值聚集兼备.通过对3个年份的冷热点比较分析发现,排放强度的冷点地区变化较小,热点地区变化较大.其中,单位GDP排放强度方面,冷点地区处于东南沿海地区,热点地区则由西北地区缩小到四川、甘肃两省;而单位人口排放强度方面,冷点地区范围有所缩减,热点地区则由分散转变为集中分布于京津冀及周边的山西、内蒙古和辽宁等.分析人为源气态活性氮时空分布格局和特征及其形成原因,可为评估和减缓气态活性氮排放对生态环境的影响提供科学基础.     

Some observations on copper yields and ore grades

The paper examines trends in the average copper content of mined ores over the years. It has tended to decline over the long term, but by no means evenly. US averages are not typical of global averages, at least in the past four decades. Those have been both higher, and less volatile than in the US. One reason for falling averages is a change in the type of deposit mined, with a rise in the share of relatively low grade porphyry deposits. The different nature of their deposits is reflected in marked differences in grades between the different continents. African and Australian average grades are higher than the global average, and changes in the share of Central Africa in global output have affected the global average grade. Yields are have been consistently lower in North America than elsewhere, and Latin American average grades have trended downwards, reflecting both the ageing of mines and the rising share of production from porphyry deposits. Typically the yield of mines declines over time as mining proceeds. The average copper content of ore deposits is usually below the average yield of the ore accessed in the early years of production. The initial grades of new mines have not declined over the past forty years, and there has been no perceptible tendency for the average grade of porphyry deposits brought into production to decline over time. There is no apparent correlation between average grade and deposit size, but mine operators tend to exploit economies of scale to offset low grades. The relationship between the annual percentage yields (the head grade) and the reserve grades of deposits is not static. In recent years head grades have fallen closer to reserve grades. The relationship may be affected by movements in metal prices. Although the evidence about the influence of prices is not clear-cut, it does suggest that prices and cut-off grades may be inversely related. As many ores contain other valuable metals besides copper, copper yields will sometimes be subordinated to the extraction of these other metals. Copper equivalent grades have not moved in the same way as copper grades alone.     

西安市黑碳气溶胶浓度特征及与气象因素和常规污染物相关性

利用西安市环境监测站超级站2013年9月1日—2015年5月31日黑碳气溶胶(BC)的监测数据,研究空气中BC浓度特征及其与气象因素和常规污染物相关性。结果表明:BC小时平均浓度均值在春季、夏季和冬季的变化趋势呈"W"型,秋季呈"V"型,且冬季的第一个最低值和峰值比春季和夏季的分别延迟1 h和2~3 h,且20:00~次日6:00秋季BC小时平均浓度均值高于当年冬季。BC浓度在秋季和冬季较高,夏季较低。冬季BC/PM_(2.5)基本最低,秋季BC/PM_(2.5)相对最高。BC日平均浓度与气温、降水和风速的日平均值为极负显著相关,且风速小于1.0 m/s时,其与风速呈最显著的负相关。除O_3外,BC日平均浓度与其他常规空气污染物浓度呈显著相关,表明其同源性很强,且受机动车尾气排放的影响更大。     

Sorption Kinetics of Atrazine and Diuron in Soils from Southern Brazil

Abstract

Sorption kinetics of atrazine and diuron was evaluated in soil samples from a typical landscape in Paraná. Samples were collected (0–20 cm) in a no-tillage area from Mamborê, PR, which has been cultivated under a crop rotation for the last six years. Six sampling points of the slope were selected to represent a wide range of soil chemical and physical properties found in this area. Radiolabeled tracers (¹⁴C-atrazine and ¹⁴C-diuron) were used and the radioactivity was detected by liquid scintillation counting (LSC). Sorption was accomplished for increasing equilibration periods (0.5, 1.5, 3, 6, 12, 24, and 48 h). Kinetics data fitted adequately well to Elovich equation, providing evidences that soil reaction occurs in two distinct stages: a fast, initial one followed by a slower one. During the fast phase, 34–42 and 71–79% of total atrazine and diuron applied were sorbed to soil samples. No important differences were found among combinations of soil and herbicide sorption during the slow phase. The unrealistic conditions under batch experiments should be overestimating sorption in the fast phase and underestimating diffusion in the slow phase. Sorption of both herbicides was positively correlated to organic carbon and clay contents of soils, but atrazine was much less sorbed than diuron, showing its higher potential to contaminate groundwater, specially in sandy, low organic carbon soils.     

The reliability of experts' opinions in constructing a composite environmental index: The case of ESI 2005

The complexity of the environment demands a well-constructed composite environmental index (CEI) to provide a useful tool to draw attention to environmental conditions and trends for policy purposes. Among the common difficulties in constructing a proper CEI are uncertainties due to the selection of the most representative underlying variables or indicators. A degree of uncertainty accompanies experts' judgments, and to deal with vague, subjective or inconsistent information, logic other than classic is required. This study analyzes a procedure that uses different experts' opinions in constructing a CEI, with the use of paraconsistent annotated logic. For this, a sensitivity analysis of the Environmental Sustainability Index (ESI 2005) was used as an example to assess the reliability of experts' opinions. The uncertainty due to the disagreement in experts' opinions clearly indicates that the forms we presently use to measure and monitor the actual environment are insufficient, that is, there is a lack of a “science of sustainability”.