荒漠草原无林地PM2.5、PM10时间变化特征及与气象因素的关系

选取荒漠草原无林地的PM_(2.5)、PM_(10)浓度以及气象因子数据,对颗粒物浓度的时间变化特征及其与气象因子的关系进行分析。结果表明:(1)1月的PM_(2.5)、PM_(10)月平均浓度最高,7月的PM_(2.5)与PM_(10)达到最低。季节尺度上PM_(2.5)、PM_(10)浓度变化为由大到小顺序依次为冬季秋季春季夏季。(2)风速≤4.0 m/s时,随着风速增加,PM_(2.5)、PM_(10)浓度不断降低;当风速4.0 m/s时,PM_(2.5)、PM_(10)浓度随风速增加而增加。PM_(2.5)、PM_(10)浓度与温度负相关。相对湿度≤50%时,随着相对湿度增加,PM_(2.5)、PM_(10)浓度呈增加趋势;相对湿度50%时,随着空气湿度增加,PM_(2.5)、PM_(10)浓度呈降低趋势。随着大气气压上升,PM_(2.5)与PM_(10)浓度随之增加。(3)不同季节的气象因子对PM_(2.5)、PM_(10)影响存在差异。     

Factors controlling the formation of persistent free radicals in hydrochar during hydrothermal conversion of rice straw

Environmental Chemistry Letters - In the environment, persistent free radicals (PFR) have adverse effects on human health. PFR are generated by thermal conversion of biomass, such as hydrothermal...     

硫酸粘菌素对土壤反硝化细菌nirS、nosZ基因多样性的影响

建立室内的土壤硫酸粘菌素暴露胁迫模型,采用末端限制性片段长度多态性分析(terminal restriction fragment length polymorphism,T-RFLP)技术分析不同浓度硫酸粘菌素残留对土壤反硝化细菌的影响。结果表明,每个处理组nirS、nosZ基因的分类操作单元(Operational Taxonomic Units,OTU)总数均比对照组低,且nirS基因呈现剂量依赖效应;各组优势细菌nirS基因主要集中在10个片段中,nosZ基因主要集中在18个片段中,nirS基因较nosZ基因丰度变化大;多样性指数分析表明,nirS基因Shannon指数在7 d时,高浓度组较对照组差异显著(P0.05); Simpson指数在各浓度处理组较对照组差异均显著(P0.05); Pielou指数在7 d、49 d时,高浓度处理组与对照组差异显著(P0.05); nosZ基因Shannon指数在35 d时,中浓度组与对照组差异显著(P0.05); 49 d时,低浓度组与对照组差异显著(P0.05); Simpson指数在21 d、35 d时,低浓度组与对照组差异显著(P0.05); Pielou指数在各处理组之间差异均不显著(P0.05)。当药物含量≥5 mg·kg~(-1)时,反硝化细菌的均匀度、群落多样性降低,优势度升高,群落结构特征均发生改变,其中对nirS基因影响显著。nirS基因更适合作为硫酸粘菌素污染的指示基因。     

全工业固废原料制备水泥工艺的生命周期评价研究

运用生命周期评价(LCA)方法,对以电石渣等工业固废为全部原料的水泥制造工艺产生的环境影响进行评价.通过对生产工艺进行分解及建模,基于实际数据建立生命周期清单,利用ReCiPe2016方法,在全球变暖、化石资源消耗、土地占用等17个小类及人体健康影响、生态系统影响及资源消耗3个大类中对工艺产生的环境影响进行评价.评价过程包括特征化、标准化和敏感性分析.结果表明,在以1 t成品水泥为功能单位的生产过程中,造成的环境影响总值为-0.0045 pt,其中,在人体健康影响和生态系统影响分类下最为显著,分别为-0.0027 pt和-0.0020 pt.与传统水泥生产相比,本工艺具有更低的资源能源消耗与碳排放量.固废作为原料来源带来的正面环境效益最为显著,而熟料煅烧与水泥粉磨则显示出最大的环境损害,也说明由于消纳了大量工业固废,本工艺对环境总体上是有益的.     

输油站的安全管理与消防

从输油站安全管理的方针、目的、管理对象及内容等方面进行分析和阐述,提出了预防输油站事故发生的技术措施和管理措施,可为输油站安全运营提供参考。     

Permitted emissions of major air pollutants from coal-fired power plants in China based on best available control technology

Based on the activity level and technical information of coal-fired power-generating units (CFPGU) obtained in China from 2011 to 2015, we, 1) analyzed the time and spatial distribution of SO₂ and NO_x emission performance of CFPGUs in China; 2) studied the impact of installed capacity, sulfur content of coal combustion, and unit operation starting time on CFPGUs’ pollutant emission performance; and 3) proposed the SO₂ and NO_x emission performance standards for coal-fired power plants based on the best available control technology. Our results show that: 1) the larger the capacity of a CFPGU, the higher the control level and the faster the improvement; 2) the CFPGUs in the developed eastern regions had significantly lower SO₂ and NO_x emission performance values than those in other provinces due to better economic and technological development and higher environmental management levels; 3) the SO₂ and NO_x emission performance of the Chinese thermal power industry was significantly affected by the single-unit capacity, coal sulfur content, and unit operation starting time; and 4) based on the achievability analysis of best available pollution control technology, we believe that the CFPGUs’ SO₂ emission performance reference values should be 0.34 g/kWh for active units in general areas, 0.8 g/kWh for active units in high-sulfur coal areas, and 0.13 g/kWh for newly built units and active units in key areas. In addition, the NO_x emission performance reference values should be 0.35 g/kWh for active units in general areas and 0.175 g/kWh for new units and active units in key areas.

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Fast and Living Ring-Opening Polymerization of l-Lactide Initiated with In-situ–Generated Calcium Alkoxides

The ring-opening polymerization of l-lactide with calcium alkoxides generated in-situ from bis(tetrahydrofuran)calcium bis[bis(trimethylsilyl)amide] and 2-propanol are presented. The polymerization in THF at room temperature proceeds rapidly and in a living manner, giving poly(l-lactide)s of controlled molecular weight, low polydispersity, and tailored end-functionalities. Kinetic studies show the absence of an induction period and a pseudo-first order rate constant of 6.41 L mol^–1 min^–1, which is significantly higher than for related Y₅(-O)(O ⁱ Pr)_13– or aluminum alkoxide-initiated polymerizations. The initiation involves a two-step process: (1) alcoholysis of bis(tetrahydrofuran)calcium bis[bis(trimethylsilyl)amide] to give the corresponding calcium alkoxide and (2) ring-opening of l-lactide via acyl-oxygen cleavage and insertion into the calcium-alkoxide bond. In the presence of excess alcohol, fast and reversible exchange between free alcohol molecules and coordinated alkoxide ligands takes place. This allows tuning of the poly(l-lactide) molecular weight over a wide range.     

Oxidative remobilization of biogenic uranium(IV) precipitates: effects of iron(II) and pH

The oxidative remobilization of uranium from biogenic U(IV) precipitates was investigated in bioreduced sediment suspensions in contact with atmospheric O2 with an emphasis on the influence of Fe(II) and pH on the rate and extent of U release from the solid to the aqueous phase. The sediment was collected from the U.S. Department of Energy Field Research Center (FRC) site at Oak Ridge, Tennessee. Biogenic U(IV) precipitates and bioreduced sediment were generated through anaerobic incubation with a dissimilatory metal reducing bacterium Shewanella putrefaciens strain CN32. The oxidative remobilization of freshly prepared and 1-yr aged biogenic U(IV) was conducted in 0.1 mol/L NaNO3 electrolyte with variable pH and Fe(II) concentrations. Biogenic U(IV)O2(s) was released into the aqueous phase with the highest rate and extent at pH 4 and 9, while the U remobilization was the lowest at circumneutral pH. Increasing Fe(II) significantly decreased U remobilization to the aqueous phase. From 70 to 100% of the U in the sediments used in all the tests was extractable at the experiment termination (41 d) with a bicarbonate solution (0.2 mol/L), indicating that biogenic U(IV) was oxidized regardless of Fe(II) concentration and pH. Sorption experiments and modeling calculations indicated that the inhibitive effect of Fe(II) on U(IV) oxidative remobilization was consistent with the Fe(III) oxide precipitation and U(VI) sorption to this secondary phase.     

驱排剂解堵工艺的研究与应用

吐哈温米油田属于低孔、低渗、低产能油藏,原油含蜡量、沥青质较高,油井的近井地带结垢严重。文章介绍了驱排剂的解堵作用原理、酸化工作液配方、驱排剂解堵工艺技术和现场应用效果。研究结果表明,驱排剂解堵工艺技术对解除油井的堵塞具有良好的效果,对提高油井的产液能力有重要作用,同时又是低渗透油田增产的一种新工艺。从2004年7月份开始,温米油田利用驱排剂解堵后油井平均单井日增油量3.0t,日增液量21.0t,动液面平均上升400.00m,平均单井有效生产期为90天以上。     

高密度电阻率法在排石场稳定性评价中的应用

简述了高密度电阻率法的工作原理。在将高密度电阻率法实际应用于排石场的稳定性评价中时,根据各种装置的特点和T、λ参数对高低电阻率的表征特性,进行了多装置及多参数的探测。通过对各二维反演视电阻率成果图的综合对比和解释,划分出了存在地质隐患的区段。经钻孔验证,效果很好。结果表明通过高密度电阻率法多装置、多参数勘探,可以确定地下介质的电阻率及其电阻率特征,进而对排石场的稳定性做出评价,对同类地质情况的监测、预警,也是行之有效的。