SPE-PDA/FLD串联HPLC法测定水样中痕量多环芳烃

建立了固相萃取-PDA/FLD串联HPLC法测定水样中多环芳烃(PAHs)的分析方法,优化了固相萃取条件.结果表明,对1L水样加入10%有机改性剂进行固相萃取,采用3ml四氢呋喃洗脱后进行HPLC分析,平均回收率在95.22%-100.8%间,相对标准偏差为0.78%-6.68%,方法的检出限在0.03-220 ng·l-1之间.     

二羟基苯甲酸的硅烷化及其在气质联用测量气相OH自由基的应用

通过优化GC-MS参数有效分离了水杨酸(SA)及其羟基化产物2,3-DHBA和2,5-DHBA的硅烷化产物,检测限分别为10.2 fmol和9.9 fmol.采用浸渍膜捕集OH标准源发生体系产生的OH自由基,测得气相OH自由基与固相SA反应生成的2,3-DHBA 和2,5-DHBA的产率分别为52%和48%.因此,SA捕集-硅烷化衍生-气质联用测量方法研究大气OH自由基有很好的应用前景.     

酒精废水消化液生物硝化和脱氮试验

酒精糟液厌氧消化液CODCr浓度为3500～4300mgL,BOD5浓度为1500～2100mgL,TN浓度为400～700mgL,NH3N浓度为300～600mgL。采用SBR反应器对该消化液进行生物脱氮试验,对反应器的有机负荷、氨氮负荷、脱氮效果、脱氮过程中氮形态的变化以及碳源提供等进行了研究分析。试验结果表明,当消化液碳源充足,SBR充水比λ=0.35,缺氧时间3h以及BOD5污泥负荷0.26～0.32kgkg·d条件下,SBR处理出水CODCr598～632mgL,BOD560～100mgL,氨氮6～9mgL,总氮200～216mgL,总氮去除率为60%左右。该处理系统中缺氧段反应时间仅为3h,却承担70%～75%的CODCr总去除负荷,显著提高了该系统的有机负荷和氨氮负荷。在消化液碳源不足的条件下,可投加乙酸钠作为生物脱氮的外碳源,投加量宜为500mgL。     

二氧化硫质量浓度在线监测子系统

烟气二氧化硫在线监测系统由2个子系统(二氧化硫质量浓度监测子系统和二氧化硫流速及流量监测子系统)构成。文中对系统的监测原理、方案等做了简要介绍,对二氧化硫质量浓度在线监测子系统做了较充分的论述。     

Women executives and off-the-job misconduct by high-profile employees: A study of National Football League team organizations

The risk of off-the-job misconduct by high-profile employees is a serious concern of top management in professional sport organizations, media and entertainment companies, and public-facing entities in the government and education sectors. Yet there is little research on how to prevent or mitigate this form of misconduct in organizations. Utilizing upper echelons theory and the literature on demographic composition, we examine the relationship between the gender composition of executives of team organizations in a men's professional sport league and subsequent misconduct by players on those teams. Specifically, we employed multilevel and logistic regression analyses to unique data on U.S. National Football League team organizations, and we found that firms with a critical mass of women executives experienced fewer player arrests. No support was found for executive power as a moderator of this relationship. We discuss the implications of our findings for the demographic composition literature. We also offer guidance for preventing and managing off-the-job misconduct by high-profile employees.     

碳纤维混凝土的耐火性能试验测试与分析*

为研究不同碳纤维体积掺量（0,0.2%,0.6%,1%,1.5%,2%）对混凝土耐火性能的影响,考察不同温度环境下（20,60,100,300,500,800 ℃）的混凝土质量损失率与抗压强度损失率的变化情况;分析高温环境下混凝土的静置时间（0,1,3,7,12 h）对混凝土抗压强度损失率的影响。结果表明:随着碳纤维掺量的增加,混凝土质量损失率与抗压强度损失率呈现先下降后增加的趋势,其纤维掺量的拐点为1%;随着环境温度的上升,纤维混凝土的质量损失率与抗压强度损失率逐渐增加,并呈非线性增长趋势。随着静置时间的增加,混凝土抗压强度损失率逐渐增加,且呈非线性增长趋势。     

Droplets behaviors of flashing jet in accidental release of superheated liquid

Structural failure of an industrial superheated liquid tank or pipe usually results in the flashing jet consisting of a mixture of massive droplets and vapor due to the violent phase transition. In this work, experiments on small-scale releases were carried out with a 20 L storage tank to investigate the droplets behaviors of flashing jets after accidental releases of superheated liquid. Distribution of droplets axial, radial and vertical velocities, as well as droplets diameter along the centreline of flashing jet, were acquired employing a Phase Doppler Anemometry (PDA). The influence of storage pressure, superheat, and nozzle diameter was also studied. Results show that the distribution of actual droplets with different velocities and diameters follows the normal distribution. Droplets mean three-dimensional velocities on the central axis of flashing jet decrease exponentially with the increase of axial distance. The droplets mean diameter first decreases exponentially and finally keeps sable at about 10 μm. Among three-dimensional velocities, the axial velocity is the highest and the vertical velocity is the lowest. Droplets mean three-dimensional velocities increase with the increase of storage pressure, superheat, and nozzle diameter. The droplets mean diameter decreases with the increase of superheat and nozzle diameter but increases with the increase of storage pressure.     

高效液相色谱在水环境监测中的应用分析

现阶段,随着我国城市化建设的不断推进,一些大型工程的施工以及工业的发展,都成为了对于水资源造成污染和破坏的主要因素,因此对于水资源的保护迫在眉睫。为了能够进一步保护水资源,通过高效液相色谱来开展水环境监测工作,能够更加全面和高效地监测水资源的污染情况,进而为之后的水环境治理工作提供有力支持。本文主要阐述了高效液相色谱的系统构成,并分析了该技术在水环境监测工作中的具体应用。     

玉米酒精生产过程COD产污系数计算模型的建立

基于玉米酒精生产工艺流程,采用实测和物料衡算结合的方法,分析玉米酒精生产关联物料,并建立关联物质量平衡方程。实验测得绝干全玉米的COD负荷值为1611 mg/g,在此基础上推导出玉米酒精生产工艺的COD产污系数与淀粉出酒率、玉米淀粉含量、胚芽收率、玉米油收率、杂醇油收率和干玉米酒糟收率的量化模型。采用国内行业相关参数值代入模型进行核算,并与《第一次全国污染源普查工业污染源产排污系数手册》和《清洁生产标准酒精制造业》(HJ 581—2010)中的相关系数进行对比。结果表明:手册值在模型计算范围内;模型计算值略大于标准指标,与标准中一级COD产污指标基本一致。     

Ultra trace simultaneous determination of 50 polycyclic aromatic hydrocarbons in biota using pMRM GC-MS/MS

Abstract

A saponification extraction method with gas chromatography pseudo-MRM (pMRM) mass spectrometry detection was developed for the determination of 50 total polycyclic aromatic hydrocarbons (TPAH50, a combination of parent and alkylated homologues) in biota. The method was aimed at monitoring and identification of potential TPAH contaminants in bitumen impacted environments. Alkylated PAHs were determined by multi-level, quantitative calibration using parent PAHs. The developed and thoroughly validated method required only one injection for TPAH50 analysis which represents significant saving of time and expensive authentic alkylated standards. The current method was tested with certified reference mussel tissue NIST 1974c and performed well. In a comparison study, the method reached a limit of quantitation (LOQ) for the TPAH50 between 0.1 and 0.2?ng g^?1, while the QuEChERs enhanced matrix removal – lipid (EMR) kit produced by Agilent showed an LOQ of 5–10?ng g^?1. The current method relied on response factors (RF) for the quantitation of alkylated PAHs determined against parent PAHs. These RFs were shown to be stable and consistent over the course of 1 year, during which over 200 routine environmental biota monitoring samples were analyzed. The environmental biota monitoring samples analyzed include muscle, carcass and liver, with an average total PAH50 concentration of 13, 90 and 135?ng g^?1, respectively. Results show significant differences in the distributions of 1 ringed, 2 ringed, 3 ringed, 4 ringed, and 5+ ringed TPAHs between the types of biota samples.