重大危险源事故风险预警技术研究

重大危险源事故风险预警技术是事故控制技术中的一大研究重点。本文通过对比分析安全生产领域常用事故预警模型的优缺点,总结了事故预警模型的发展趋势,提出了基于模糊综合评判技术和动态模糊神经网络技术的重大危险源事故风险预警模型,详细陈述其构建过程,最后对液化石油气蒸气云爆炸事故应用该模型,得到了较好的预测效果,实现了风险程度的定量化预警。该预警模型具有快速的自学习能力和容错能力,能够同时处理多种风险因素、自动生成模糊规则并满足预警系统的实时性要求,可应用于重大危险源在线监控预警系统,为企业端和政府端监管者提供有效的重大危险源事故风险定量化预警信息,为遏制重大灾难事故的发生、减少死亡人、数受伤人数和直接经济损失提供先进的理论和技术支撑。     

生物膜净化含苯废气的性能研究

在生物法净化废气装置中生物膜是设备的主体和关键．研究以净化含苯废气的生物滴滤塔为对象,采用静态反应器对塔内生物膜的净化性能进行研究,探索其过程机理,为生物滴滤器的优化提供技术支持．结果表明,在生物滴滤器中单位体积生物膜的呼吸速率和苯去除速率都沿气流方向逐渐减小,但单位质量生物膜的苯去除速率却是塔中部高两边低．研究发现,当生物膜经过3d的闲置后,苯的消除能力提高了70％左右,但闲置时间超过5d后,生物净化性能开始下降．综合实验结果,推测在生物膜中同时存在苯的生物降解过程和生物储备能源的合成过程,在苯浓度越高的地方储备能源的量也越多,储备能源的存在降低了生物膜的净化能力但增强了生物膜的稳定性．     

Thermodynamic method for the prediction of solid CO2 formation from multicomponent mixtures

The increase in GHG concentration has a direct effect on global climate conditions. Among the possible technologies to mitigate GHG emissions, CCS is being accepted to gain emission reduction. Such technology also involves cryogenic CO₂ capture processes based on CO₂ freeze-out or where the formation of solid CO₂ must be avoided. Captured CO₂ is usually transported in pipelines for the reinjection.The risk associated to the release of CO₂ is due to the changing temperatures and pressures the system may experience, which can lead to the deposition of solid CO₂ where it must be avoided. Prolonged exposure to dry ice can cause severe skin damage and its resublimation could pose a danger of hypercapnia. It is, thus, necessary to build up a tool able to predict the conditions in which CO₂ can freeze-out.A thermodynamic methodology based on cubic EoSs has been developed which is able to predict solid–liquid–vapor equilibrium of CO₂ mixtures with n-alkanes or H₂S which are usually found in equipment for acidic gas, mainly natural gas, treatment.The focus is a detailed analysis of the method performances when more than two components are present since, for such a case, literature does not provide significant modeling results.     

6种挥发性有机物在甲苯驯化微生物中的好氧生物降解性能

利用振荡摇瓶法测定了6种典型挥发性有机物,甲苯、邻二甲苯、间二甲苯、对二甲苯、苯和氯苯在甲苯驯化微生物中的好氧生物降解性能.结果表明,在本研究的液相浓度范围内(甲苯＜174mg/L,邻二甲苯＜149mg/L,间二甲苯＜129mg/L,对二甲苯＜133mg/L,苯＜234mg/L,氯苯＜146mg/L),3种二甲苯、苯和氯苯的降解速率随其初始浓度的增大而增加,符合一级反应,这5种VOCs未对微生物产生明显的抑制或毒害作用;甲苯的液相浓度大于85mg/L时,其降解速率不随初始浓度的增大而改变,其降解规律符合Monod方程.     

东北强降水时空变化的特征和原因分析

利用东北地区近45 a(1961-2005年)4-9月逐日降水量资料计算了强降水集中度和集中期,分析了强降水集中度和集中期时空变化特征,讨论了影响强降水集中度和集中期的环流特征变化。结果发现,东北强降水集中度与强降水有很好的相关性,对于强降水有着很好的指示作用。从空间分布上看东北雨季强降水集中度由东向西趋于集中。从时间变化方面来看,1960年代中期到1980年代初,强降水集中度处于低值区,而在1991年之后东北地区强降水集中度大多处于高值区。强降水集中期仅在1970年代处于低值偏多的时期。对于东北不同区域大部分地区(除东北西北部外)在1990年代之后集中度都有所增加,集中度大值年出现的频率增加,而东北西北部的变化正好相反。东北地区强降水集中度偏高时,东北地区整层处于低压中心,在东北东部海面上有高压存在。东北地区存在着偏西气流和东南暖湿气流的交汇,在40～50°N纬度范围内高度场呈"+－+"波动。集中度偏高时东北东部地区有上升的垂直速度中心,并且上升速度随高度升高(300 hPa以下)而增强。东北地区水汽主要来源于鄂霍次克海冷湿空气。在东北地区存在着水汽通量散度的负距平中心,形成水汽异常辐合区,有利于强降水的出现。     

Influence of manufacturing process on the residues of certain fungicides used on tea

Green tea shoots which were sprayed with fungicides such as hexaconazole, propiconazole, carbendazim, and tridemorph were collected from tea bushes after 24 h of fungicide application to study the effect of manufacturing process on the residues. Significant loss of residues was noted at each stage of the manufacturing process. The total loss in residues upon manufacturing of these fungicides ranged from 12.20% to 57.14%. Among the various influential factors that determine the loss of residues, vapor pressure of the fungicides was most prominent in the contribution to residue loss. A high vapor pressure of the fungicide tridemorph amounted to a residue loss of 57.14%, while the low vapor pressure of the other three fungicides caused a loss of less than 22.22%.     

Predicting the acute lethality of a chlorinated benzene mixture in soils: a comparison of solid-phase microextraction,body residue,and solvent extraction techniques

When predicting the adverse effect(s) of chemical pollution on an exposed organism, a measurement of body residue is often considered a more accurate estimate of dose than those estimates derived from a solvent extraction or solid-phase microextraction of the polluted exposure medium. The magnitude of this perceived difference in accuracy, and thus the accuracy of the corresponding toxicity prediction, were investigated in the present two-phase study. In Phase I, an acute lethality response was correlated with dose estimates derived from body residue, solvent extraction, and SPME. In Phase II, acute lethality was predicted from Phase I data. The accuracy of Phase II toxicity predictions was determined by comparing predicted mortality to observed mortality. Although this study revealed that body residue indeed provided the most accurate prediction of toxicity, the margin of this comparatively greater accuracy suggests that alternative methods may provide equally viable dose estimates and, subsequently, equally viable toxicity predictions.     

Determination and QSPR analysis of log Kow and log Koc for fluorine containing benzene derivatives

Octanol‐water partition coefficients (Kow) and soil organic carbon sorption coefficients (Koc) were determined for 14 fluorinated benzene derivatives. Quantitative structure‐property relationships were developed using molecular connectivity indices and quantum chemical parameters to analyze the most significant factors influencing these physico‐chemical properties of the compounds. The substitution by F in benzene derivatives has greater influence on Koc than on Kow.     

黑河流域水汽输送及收支特征

利用NCEP/NCAR逐日再分析资料对黑河流域的水汽输送和收支特征进行了计算分析,结果表明:西风环流使得源于大西洋和北冰洋的水汽成为黑河流域空中水汽的主要来源,流域内水汽输送以自西向东的纬向输送为主,东边界输出强度强于西边界输入强度,纬向净输入量为负;经向输送为自北向南且在强度上不及纬向输送,北边界输入强度强于南边界输出强度,经向净输入量为正。700 hPa气层流域南部的水汽辐合辐散特征随季节变化显著,冬季为水汽辐散区,夏季为水汽辐合区;流域北部没有明显的水汽辐合辐散特征。全流域多年平均水汽输入量为997.3 km³,输出量为1 046.1 km³,净输入量-48.8 km³,20世纪60年代中期以后流域水汽净输入量呈现增加趋势。黑河流域北部荒漠区年内各季均为水汽输出期,中低层大气(地面~500 hPa)为主要的水汽输出层;南部山区年内6-9月为水汽输入期,低层大气(地面~700 hPa)为水汽输入层,中高层大气(700~300 hPa)为水汽输出层。据大气水平衡原理,黑河流域多年平均蒸发量约为84 km³。     

土壤理化性质对污染场地环境风险不确定性的影响

以某化工污染场地中挥发性有机物苯的环境风险评价为例,研究了土壤有机质含量、土壤含水率、土壤容重等理化性质对风险评价结果的影响.在土壤污染物苯浓度不变的前提下,土壤有机质含量、土壤含水率和土壤容重在场地条件下随机取值的变异范围分别为0.31%～2.31%、0.12～0.25和1.25～1.75 g/cm3.10 000次蒙特卡罗模拟结果表明,在95%置信水平下,苯的总致癌风险(概率值)在1.45×10-5～2.74×10-5之间.在该场地条件下,土壤有机质含量是影响苯风险不确定性的最主要因素,其对风险评价结果不确定性的贡献率高达90.2%;土壤含水率和土壤容重的贡献率分别为5.6%和4.2%.因此,在土壤污染健康风险评价过程中,应对理化参数进行敏感性分析,对评价结果影响较大的关键参数取值需慎重.