油田高盐浓度废水对其生化处理的影响

根据油田压裂液废水中的盐浓度对生化处理系统的影响,对生化处理系统中活性污泥的生物学变化规律进行了实验研究。结果表明:当废水中盐浓度低于2.5×104mg/L时,废水生化处理系统对COD的去除率可稳定在92%左右,污泥活性良好;当废水中盐浓度达到2.5×104mg/L时,污泥活性开始受到抑制,COD去除率急剧下降(稳定在80%左右);当盐浓度达到3.5×104mg/L时,COD去除率下降到60%左右;当废水中盐浓度达到6.0×104mg/L时,污泥活性系统趋于崩溃。     

Simulation of phytoremediation of a TNT-contaminated soil using the CTSPAC model

Knowledge of water movement in the plant-xylem system and contaminant bioavailability in the soil environment is crucial to evaluate the success of phytoremediation practices. This study investigated the removal of 2,4,6-trinitrotoluene (TNT) from a contaminated sandy soil by a single poplar (Populus fastigiata) tree through the examinations of temporal variations of xylem water potential, root water uptake, and soil TNT bioavailability. A mathematical model, CTSPAC (Coupled Transport of water, heat, and solutes in the Soil-Plant-Atmosphere Continuum), was modified for the purpose of this study. The model was calibrated using laboratory measurements before its application. Our simulations show that the xylem water potential was high in the roots and low in the leaves with a potential head difference of 3.55 cm H2O, which created a driving force for water flow and chemical transport upward from the roots through the stem to the leaves. The daily average root water uptake rate was 25 cm3 h(-1) when an equilibrium condition was reached after 24 h. Our simulations further reveal that no TNT was found in the stem and leaves and only about 1% of total TNT mass was observed in the roots due to the rapid biodegradation and transformation of TNT into its daughter products. About 13% of the soil TNT was removed by the poplar tree, resulting mainly from root uptake since TNT is a recalcitrant compound. In general, the soil TNT bioavailability decreased with time due to the depletion of soil solution TNT by the poplar tree. A constant bioavailability (i.e., 3.1 x 10(-6)) was obtained in 14 d in which the soil TNT concentration was about 10 mg L(-1). Our study suggests that CTSPAC is a useful model to simulate phytoremediation of TNT-contaminated sites.     

网络路由信息安全应用研究——基于流量预测的路由选择新算法

根据灰色系统的预测理论 ,笔者提出了一种关于网络数据流量变化发展的预测方法 ,并为其建立了基于网络流量变化趋势的预测模型。依据该模型对网络中各结点未来流量的预测结果 ,可用实时动态来确定最佳的路由选择策略 ,从而在根本上解决网络拥塞现象的发生 ,大大地提高了网络数据通信时的安全可靠性。     

烧碱生产过程危险评估及对策措施

离子膜烧碱生产过程中涉及多种危险有害因素。笔者通过对国内现役离子膜烧碱生产装置进行调研 ,同时结合国内外其他涉及烧碱生产厂家的情况 ,分析并指出了生产过程中可能出现的危险有害因素 ,进而提出了相应对策措施 ,为企业消除事故及安全生产可以提供保障     

论我国公共资源安全问题

介绍了公共资源及公共资源安全的概念,探讨了公共资源的安全问题与中国经济和社会发展的关系.结合6个具体案例分析了中国现有的公共资源安全问题.给出公共资源安全的风险管理的概念和评价方法,并以此为基础,提出6条保证公共资源安全的对策.     

An estimate on the rainout of atmospheric CO2

IntroductionCarboncirculatesbetweentheatmosphere ,biosphere ,oceansandthelithosphere(Warneck ,1988) .Thecarbonfluxesbetweenthesereservoirs,suchasburningoffuels ,photosynthesisandrespirationofecosystems,andtheuptakeoftheocean ,havebeenestimatedquantitative…     

Volatilization behaviors of diesel oil from the soils

The volatilization of diesel oil, Shengli crude oil and 90 # gasoline on glass surface of petri dishes were conducted at the ambient temperature of 25℃. Diesel oil evaporates in a power manner, where the loss of mass is approximately power with time. 90 # gasoline evaporates in a logarithmic with time. Where as the volatilization of Shengli crude oil fit either the logarithmic or power equation after different time, and has similar R^2 . And the effects of soil type and diesel oil and water content on volatilization behavior in unsaturated soil were studied in this paper. Diesel oil and water content in the soils play a large role in volatilization from soils. Appropriate water helps the wicking action but too much water stops it. The wicking action behaves differently in four different types of soils in the same volatilization experiment of 18% diesel oil content and air-dry condition.     

高效、多功能一氧化碳防护材料

本文介绍了一种高效、多功能的钯-炭型（Pd/C）一氧化碳（CO）常温催化剂。装罐试验表明：在该催化剂装药量为35～50g的条件下，对模拟呼吸量为30L/min、初始CO浓度为3125mg/m^3的CO净化率大于99.5%，防护时间可达数小时，同时对氢氧酸（HCN）、有机气体等具有很好的综合防护效果。与传统的霍加拉特剂相比，该催化剂具有防护效能高、抗温性和抗陈化性强的突出特点。     

水环境中重金属铜暴露下青鳉鱼的行为响应

采用生物行为传感器监测青鳉鱼在重金属铜暴露下的行为数据,分析不同暴露浓度(20、10、5、1和0.1 TU)下青鳉鱼的行为响应。20、10、5、1和0.1 TU的暴露浓度下青鳉鱼对重金属污染的行为反应模式符合环境胁迫阈值模型,且不同浓度梯度重金属对青鳉鱼产生不同的行为毒性效应。利用重金属作用下青鳉鱼的行为变化来研究重金属环境胁迫导致的生物行为响应机制,从而得到重金属暴露下生物行为的实时变化过程和趋势,可对水环境生态系统质量进行综合评价。     

地铁列车火灾中的人员疏散仿真研究

近年来,随着城市人口的不断激增,地铁行业也随之蓬勃发展,地铁列车已经从城市交通的辅助角色转变成人们生活中的关键需求,因而做好地铁的消防安全工程势在必行。针对列车火灾的人员疏散问题进行了模拟分析,考虑列车车厢内4种人员密度疏散的场景,通过软件模拟分析,将结果与规范计算所得结果进行比对,较为真实可靠地反映了人员密度对疏散的影响,并在此基础上提出相关建议。