水汽对低温光学元件污染的研究

就水汽对光学元件的污染进行了定量的分析、测试．建立了水汽冷凝膜在５．５～７．１μｍ和１０．５～１２．５μｍ的波段的吸收模式．实验结果与理论计算相吻合，测试精度优于３％．     

Nitrate contamination of groundwater: Measurement and prediction

Agriculture makes a significant contribution to the diffuse source contamination of surface and groundwater resources, particularly contributing to the NO ₃ ^- contamination of groundwater. Two approaches were adopted to evaluate management practices (within the context of the whole farming system) for their impacts on the environment : (1) measurement of the quality of groundwater under different farming systems, and (2) comparison of predictions of the impact of farming systems on water quality, obtained using whole farm N budgets, with measured values.The Ontario Farm Groundwater Quality Survey evaluated the rural groundwater quality in Ontario, with respect to common contaminants including NO ₃ ^- . Approximately 1300 domestic farm wells were sampled, and wells were drilled in some fields of farms involved in the study. NO ₃ ^- was present at concentrations above the maximum acceptable for drinking water (10 mg N 1^–1) in 14% of wells, including 7% of wells that also had unacceptable concentrations of coliform bacteria. Significant levels of NO ₃ ^- contamination were observed under most agricultural land use practices investigated.Calculation of N budgets was simplified by assuming that there was no net change in the N content of farm assets. The N inputs to agricultural systems considered were: purchases from off-farm suppliers, N₂ fixation and atmospheric deposition. Symbiotic N₂ fixation was estimated from empirical relationships between crop yield and N₂ fixed. The N outputs were in sales of plant and animal produce, gaseous and leaching losses. Gaseous loss was assumed to result only from volatilization of ammonia, estimated to be 39% of total manure N.We have identified one cash crop farming system where there was a true balance. The rotation included corn soybeans and wheat, with two years of soybean always being grown before corn. Many livestock farms, including two organic farms, gave large imbalances of N which might indicate that these operations were not in equilibrium.The relationship between measured and predicted values of NO ₃ ^- -N expected in the groundwater under the different management systems showed that the simplified N budget overestimated the NO ₃ ^- -N concentration by about one third. However, the budget approach appeared to identify farms where contamination was likely even if the actual amount was over estimated. Simplified budgets could therefore be used to compare the potential of different farming systems for causing environmental contamination.     

工作人员^131I体内污染测量及剂量估算

本文介绍了用人体计数器测量工作人员~(131)I 体内污染和用 Ge(Li)γ谱仪测量尿中~(131)I 放射性核素的活度。根据实测数据外推求其摄入量,并进行了剂量估算和评价。     

Continuum and Fracture Mechanical Studies of Contaminated Bonding Surfaces

The importance of fracture mechanics testing of contaminated bonding surfaces is discussed. The sensitivity of adhesive bond systems to contamination may increase dramatically when macroscopic cracks are present. A bond system is shown to retain a significant level of tensile adhesion strength at relatively high levels of contamination, yet have near zero mode I fracture toughness at very low levels of the same contaminant. Silane adhesion promoter is shown to reduce greatly the system fracture toughness sensitivity to contamination, especially at lower levels of contamination.     

Study of nickel contamination on the ultrasonic bondability of gold bond finger of SD-48L packages

Contamination is a major barrier to the adhesion of solid-phase metal couples. If me-tallic impurities are present on a gold (Au) bonding surface, it can easily react with oxygen molecules in the atmosphere to form oxides. The oxides formed prevent intimate metal-metal contact which is important for bond formation. A study is carried out to investigate whether nickel (Ni) contamination can affect the ultrasonic bondability of Au bond finger of side-braze 48-lead ceramic package. Two sets of samples are used for this study. The first set comprising uncontaminated packages serves as a control group. The second set are Ni contaminated packages. The results of the study show that Ni contamination does not affect the ultrasonic bondability of the Au bond finger. A second study to ascertain the quality of the wire bonds however shows that the mean bond tensile strength of the Ni contaminated packages has weakened slightly.     

Surface contaminants on annealed aluminium foil and their effects on adhesion

Surface fast atom bombardment mass spectroscopy (FABMS) and X-ray photoelectron spectroscopy (XPS) have been used to study the chemistry of the residues remaining on aluminium foil surfaces following annealing. In addition surface FABMS spectra were obtained of the base oil and additives used in the rolling lubricant. Surface FABMS analysis showed that none of the original additives or components of base oil remained on the surface following annealing. Instead the surface was partially covered with organic acid anions of varying molecular weight. The total concentrations of residues determined by XPS and surface FABMS correlated well with the variation in adhesion properties across the width of coiled, annealed foil.     

On the origin of benzene, toluene, ethylbenzene, and the xylenes in virgin olive oil-further results

Investigations into the sources of contamination of virgin olive oil by gasoline components were concluded. Olives on the tree contained volatile aromatic hydrocarbons at concentrations exceeding those corresponding to the equilibrium with the environment. Present knowledge indicates that up to 10 g/kg of benzene and 250 g/kg for the sum of benzene, toluene, and the C₂-benzenes must be considered as possible background concentrations. Aside from the oil mills, the rooms for intermediate storage of the olives were found to be an important source of contamination by gasoline vapours, since they often contain vehicles and other gasoline-driven engines. Parking of a small, hot grass mower into a similar room released an amount of gasoline that was sufficient to contaminate the oil in olives above the proposed limit by a factor of 100. Recommendations are derived for the producers to avoid contamination of olive oil with gasoline components.     

H2O/CO2组分对氢和乙烯超声速燃烧室性能影响数值模拟

文章采用数值计算方法,评估了H2O与CO2两种污染组分对氢、乙烯超声速燃烧室性能的影响。针对纯净空气和含H2O/CO2污染空气,在来流总温、总压、马赫数、氧气摩尔含量、燃料当量油气比相当的条件下对氢、乙烯超声速燃烧室分别进行了三维、二维燃烧流场数值模拟,其中氢气当量比为0.42,乙烯当量比为0.57。计算中考虑的H2O组分摩尔含量包括7.5%和17.5%,CO2组分摩尔含量为7.5%。最后,将数值计算结果与相应实验测量值进行了对比分析。研究结果表明:数值计算结果与实验测量值比较接近,反映的H2O、CO2污染组分影响趋势一致的,计算结果可以有效分辨出污染组分对燃烧室性能的影响;H2O、CO2污染组分的存在降低了燃烧总温升、燃烧效率,进而降低了燃烧室壁面压力,总体上造成燃烧室性能的下降。     

濮阳东北部金堤河两岸地下水污染状况分析

采集濮阳东北部金堤河两岸的浅层和深层地下水样进行水化学分析,指出HCO3 Na型是该研究区地下水的主要化学类型。选择水化学类型为HCO3 Na型且远离非HCO3 Na型水样点集中区域的监测点的水质数据,计算出浅层和深层地下水的水化学组分对照值,并在此基础上进行地下水污染评价,确定浅层和深层地下水的污染现状和主要污染因子。结果表明:35个浅层地下水监测点中,26个点均受到不同程度的污染,主要污染因子是COD、NO2- N和NH3 N;5个深层地下水监测点中,仅靠近金堤河的2个点的数据显示受到微污染,污染因子是溶解性总固体、SO24-和NO2- N。研究区浅层地下水受人类活动影响较强,主要污染源为含氮的农药、化肥和被污染的地表水等。     

地下水硝酸盐原位修复技术研究进展

介绍了地下水硝酸盐原位修复技术,对目前使用较多的渗透反应墙与注射井引入工程实例加以说明。指出原位修复技术不同的适用条件,同时提出浅层地下水系统本身的自然净化机制对大范围的地下水硝酸盐的防治更具经济优势。