Responses of soil ammonia oxidizers to a short-term severe mercury stress

The responses of soil ammonia-oxidizing archaea(AOA) and ammonia-oxidizing bacteria(AOB) to mercury(Hg) stress were investigated through a short-term incubation experiment.Treated with four different concentrations of Hg(CK,Hg25,Hg50,and Hg100,denoting 0,25,50,and 100 mg Hg/kg dry soil,respectively),samples were harvested after 3,7,and 28 day incubation.Results showed that the soil potential nitrification rate(PNR) was significantly inhibited by Hg stress during the incubation.However,lower abundances of AOA(the highest in CK: 9.20 × 10~7 copies/g dry soil; the lowest in Hg50: 2.68 × 10~7 copies/g dry soil) and AOB(the highest in CK: 2.68 × 10~7 copies/g dry soil; the lowest in Hg50:7.49 × 10~6 copies/g dry soil) were observed only at day 28 of incubation(P 0.05).Moreover,only the community structure of soil AOB obviously shifted under Hg stress as seen through DGGE profiles,which revealed that 2–3 distinct AOB bands emerged in the Hg treatments at day 28.In summary,soil PNR might be a very useful parameter to assess acute Hg stress on soil ecosystems,and the community structure of soil AOB might be a realistic biological indicator for the assessment of heavy metal stress on soil ecosystems in the future.     

有机氯农药污染土壤的Fenton氧化修复研究

研究了Fenton氧化对某实际有机氯农药污染场地土壤的修复效果。结果显示:Fenton氧化能够快速有效地降解污染土壤中的六氯和DDTs。当Fe2+浓度为80 mmol/L,Fe2+与H2O2的摩尔浓度比为1∶5,水土比10∶1时,反应6 h,土壤中六氯和总DDT的去除率分别为:96.7%和78.2%。每方土的修复成本估算为951元。     

自上而下的城市能源消耗碳排放估算方法

快速的城镇化进程带来城市碳排放的快速增长,准确的城市水平碳排放数据对于制定科学合理的碳减排政策极为关键,明确碳排放源的关键类别可以做到有的放矢和精准管控.但是目前中国碳排放数据的研究主要集中在国家、地区和省级层面,城市水平由于所需基础数据的不透明和不准确,长久以来缺乏完整的碳排放清单.为解决该问题,在以前相关研究的基础上,通过省级能源平衡表,尝试利用合理的分配指标从省级碳排放数据估算出下属城市的碳排放,构建了一套自上而下的城市能源消耗碳排放估算方法.通过与现有可获得的城市水平数据进行对比,发现估算差距均在10%以内,证明了该方法的可行性和准确性,并尝试在时间尺度进行了扩展.为获取在时间和空间上均连续的中国城市能源消耗碳排放数据提供了科学的方法和合理的思路,也能为各城市分配减排任务和城市间进行减排协商提供可靠的数据支撑.     

Global Warming and Global Dioxide Emission: An Empirical Study

In this paper, the dynamic relationship between global surface temperature (global warming) and global carbon dioxide emission (CO₂) is modelled and analyzed by causality and spectral analysis in the time domain and frequency domain, respectively. Historical data of global CO₂emission and global surface temperature anomalies over 129 years from 1860–1988 are used in this study. The causal relationship between the two phenomena is first examined using the Sim and Granger causality test in the time domain after the data series are filtered by ARIMA models. The Granger causal relationship is further scrutinized and confirmed by cross-spectral and multichannel spectral analysis in the frequency domain. The evidence found from both analyses proves that there is a positive causal relationship between the two variables. The time domain analysis suggests that Granger causality exists between global surface temperature and global CO₂emission. Further, CO₂emission causes the change in temperature. The conclusions are further confirmed by the frequency domain analysis, which indicates that the increase in CO₂emission causes climate warming because a high coherence exists between the two variables. Furthermore, it is proved that climate changes happen after an increase in CO₂emission, which confirms that the increase in CO₂emission does cause global warming.     

ESTIMATION OF DAILY TEMPERATURE MEANS USING ELEVATION AND LATITUDE IN MOUNTAINOUS TERRAIN1

ABSTRACT A model was developed for predicting mean daily, mean daily minimum, and mean daily maximum temperatures in West Virginia. The model is easily used since the only inputs are elevation, latitude, and julian date. With local calibration, the model is expected to apply to other areas in the Appalachian region.     

长管拖车的风险预防

本文以HGJ9550GGQ型长管拖车为例,~RETSGP,,0005-2012《移动式压力容器安全技术监察规程》的要求对产品进行风险评估,旨在为使用者制定El常操作规程和事故发生时的紧急预案提供参考。使设备在全部寿命期内处于恰当的操作、维护及管理之下,确保设备使用者及相关方的利益和人身安全。     

基于核密度估计的清代中国自然灾害时空分布特征

基于《清史·灾赈志》中的历史灾害信息,提取清代（1644-1911年）自然灾害共24 537县次,重建逐年灾害频次序列,以核密度估计法对5类主要灾害（水灾、旱灾、蝗灾、疫灾、冷害）的空间分布特征进行分析。结果表明:清代自然灾害频次序列没有明显的趋势性特征,而体现为阶段性波动,基于灾害频次30年滑动平均值可提取出4个峰值时段（1644-1673、1721-1750、1812-1841和1872-1901年）;相比于现代,清代灾害类型更加集中在农业灾害,最为多发的是水灾和旱灾,合计占总数的近80%,其次是蝗灾、疫灾和冷害;灾害最为多发的高风险区分布在黄淮海平原和长江三角洲,前者集中了水灾、旱灾、蝗灾的极端多发区,后者除了水旱多发,还是疫灾和冷害的极端多发区; 4个峰值时段的灾种类型组合和灾害多发区均有明显差异,时空变化受到致灾因子、暴露度和脆弱性因素的共同作用。上述工作有助于更好地认识历史灾害发生规律,对于当前及未来的防灾减灾工作具有重要参考价值。