室内空气环境的数值研究方法

建筑室内空气环境(IAE)与人们的舒适、健康及工作效率密切相关，对其数值模拟与评价具有重要的实际意义。由于室内存在大量离散分布的热源与污染源，IAE表现为复杂的对流传热传质过程，如何有效地利用CFD模拟技术分析与评价IAE即是本文的研究内容。作者根据室内空气环境的特殊性提出了对流传输与自然模拟方法，简洁有效地分析了二维层流置换通风房间中离散热与污染源之间的相互作用及其对IAE的影响。     

Furan in heat‐treated foods: Formation,exposure, toxicity,and aspects of risk assessment

Furan is formed in a variety of heat‐treated foods through thermal degradation of natural food constituents. Relatively high levels of furan contamination are found in ground roasted coffee, instant coffee, and processed baby foods. European exposure estimates suggest that mean dietary exposure to furan may be as high as 1.23 and 1.01 μg/kg bw/day for adults and 3‐ to 12‐month‐old infants, respectively. Furan is a potent hepatotoxin and hepatocarcinogen in rodents, causing hepatocellular adenomas and carcinomas in rats and mice, and high incidences of cholangiocarcinomas in rats at doses ≥2 mg/kg bw. There is therefore a relatively low margin of exposure between estimated human exposure and doses that cause a high tumor incidence in rodents. Since a genotoxic mode of action cannot be excluded for furan‐induced tumor formation, the present exposures may indicate a risk to human health and need for mitigation. This review summarizes the current knowledge on mechanisms of furan formation in food, human dietary exposure to furan, and furan toxicity, and highlights the need to establish the risk resulting from the genotoxic and carcinogenic properties of furan at doses lower than 2 mg/kg bw.     

白洋淀水环境承载能力计算及保护措施探讨

通过对白洋淀水量、水质平衡分析,建立水质模型,对水环境承载能力进行计算,提出白洋淀水环境保护措施:加强污水灌溉和土地处理系统工程建设;建立湿地利用和污水净化工程;采取合理的水产养殖和水质控制技术措施。     

Effect of PH3 poisoning on a Ni-YSZ anode-supported solid oxide fuel cell under various operating conditions

The Ni-YSZ anode-supported solid oxide fuel cell (SOFC) can generate electrical power by using coal-derived syngas as the fuel. However, trace contamination of phosphine (PH₃) in the syngas can cause irreversible degradation in cell performance. A series of tests at 10 ppm PH₃ in the fuel gas was carried out under a variety of operating conditions, viz, with/without electrochemical reaction in syngas and with/without H₂O in H₂ fuel at 750 °C, 800 °C and 850 °C. The poisoning effects were evaluated by both electrochemical methods and chemical analyses. The post-mortem analyses of the SOFC anode were performed by means of XRD, SEM/EDS, and XPS. The results show that the degradation rate is larger at the higher cell working temperature using syngas with PH₃ in a 200 h test though PH₃ is more reactive with Ni in the anode at lower working temperature and produces a secondary nickel phosphide (Ni_xP_y) phase. The dominant compositions of Ni_xP_y on the cell anode are Ni₅P₂ with the presence of H₂O, and Ni₁₂P₅ without the presence of H₂O. The production of Ni_xP_y can be generated on the cell anode using syngas or dry H₂ fuel with 10 ppm PH₃ contaminant. Further, the appearance of Ni_xP_y phases is independent of the electrochemical reactions in the cell.     

柳钢中板厂液压系统使用情况分析

对柳钢中板厂液压系统从安装、调试、投产到现在的使用情况进行全面分析 ,指出存在的主要问题 ,并提出改进措施及解决方法 ,以满足生产需要     

A Critical Review of Improved Oil Recovery by Electromagnetic Heating

Conventional thermal improved oil recovery (IOR) methods, such as fire flooding and steam flooding, are commercially viable when properly applied. Every conventional method has one or more limitations. If the reservoir is shallow, the reservoir pressure may be too low to maintain a steam drive. If a reservoir is too deep, wellbore heat losses become excessive. Fireflood success depends on crude composition. Each of the conventional thermal methods requires sufficient reservoir transmissibility to achieve fluid Injection. Electro magnetic heating (EMH) has the potential for overcoming some of the limitations of conventional thermal methods such as environmental, cost and depth of operation. EMH as an IOR method to heating heavy crude by increasing its transmissibility, stimulation solution in asphaltenic wells, oily pollution removal, and so on, has environmental economical and technical advantages.     

考虑引气污染物的飞机客舱送风方式对比分析

考虑到飞机座舱引气污染物传播的问题，为对比座舱不同送风方式的排污及舱内通风效果，在5排模拟座舱中通过实验测量方法展开研究。分别在天花板和混合送风方式下测量了瞬时和持续两种形式的引气污染物在座舱内的浓度分布情况，并对座舱内的空气品质进行评价。实验结果表明：天花板送风时引气污染物会先到达靠近窗户的位置，混合送风时引气污染物先到达中间座椅位置；混合送风更容易加快污染物的扩散，但其污染物浓度更低，排污速率也更高，送风量相同时混合送风下飞机座舱的通风效果及空气品质更佳。     

An analytical solution to contaminant transport through composite liners with geomembrane defects

To investigate the performance of landfill composite liner system,a one-dimensional model was developed for solute transport through composite liners containing geomembrane defects.An analytical solution to the model was obtained by the method of Laplace transformation.The results obtained by the presented solution agree well with those obtained by the numerical method.Results show that leachate head and construction quality of geomembrane(GM) have significant influences on the performance of the composite ...     

环糊精在污染土壤修复中的研究进展

环糊精由于其具有特殊的分子空腔结构,可以增容及解吸吸附在土壤中的有机污染物,并对土壤表层的有机污染物具有一定的光解促进作用,通过对环糊精改性还能达到同时去除土壤中有机物和重金属污染物的效果。目前环糊精作为环境友好型材料已经广泛的应用于环境治理中,文章介绍了环糊精及其衍生物在污染土壤修复方面的应用。     

稀土原地浸矿区地下水污染风险评价方法研究

在综合解析稀土矿区水文地质特征、原地浸矿工艺特征,以及地下水水源地的基础上,构建了地下水脆弱性、污染源和地下水价值的综合评价耦合模型,提出了针对离子型稀土原地浸矿区地下水污染风险评价的多指标评价方法,确定了系统的地下水污染风险评价指标体系.利用构建的评价方法,以我国南方某离子型稀土矿区为例,进行了地下水污染风险评价,确定了主要污染风险区域.结果表明,地下水污染风险评价分级与实际地下水水质观测的污染程度基本吻合,所建方法是合理有效的.