地表水中痕量金属元素的原子吸收法测定

采用单缝石英管技术作为火焰原子化器的原子捕集阱,以火焰法测定地表水中Cu、Pb、Zn、Cd等痕量元素,进一步提高了石英管法的灵敏度。依上述元素的顺序,其方法的最低检出浓度分别为4.0、10.0、1.0、1.0μg·l~(-1);对不同浓度标准溶液的精密度实验,其变异系数分别为0.5％、0.6％、1.6％、0.4％;对地表水加标回收率试验结果分别为95％—106％、100％—105％、95％—109％、84％—99％。     

基于统一强度理论的松散岩体的围岩压力计算

对于软弱破碎岩体,在埋深较浅的情况下,可以采用太沙基理论计算围岩压力。破裂面两侧作用着摩擦力,采用统一强度理论考虑破裂面两侧的摩擦力,从应力传递概念出发,推得了作用于衬砌上的垂直围岩压力公式。计算结果表明强度理论的效应是明显的。本文给出了围岩压力的范围值。     

SYNERGETICS ANALYSIS OF ROCK MASS BASED ON ITS CHARACTERISTIC OF DISCONTINUATION

<正>Based on the noncontinuity of rock mass, views it as a system made of blocks that are divided by dissconti-nuties. Take the relative displacement of blocks as order parameter and establish its main equation using the micro-cosmic disposal method of synergetics. Then solve this equation and get its solution of nonstationary state. Narrate the characteristic of change and interrelated factors of blocks' displacement through the analysis of nonstationary state of main equation.     

环境样品中PCBs的测定

详细地介绍了应用ＧＣ／ＭＳ或ＧＣ／ＥＣＤ测定样品的ＰＣＢｓ的分析方法及榈前处理的方法，并给出了３０个行政检查样品的测定结果。     

How effective are broad-scale nutrient mass balances for determining the sustainability of lot-feed manure application?

Nutrient mass balances have been used to assess a variety of land resource scenarios, at various scales. They are widely used as a simple basis for policy, planning, and regulatory decisions but it is not clear how accurately they reflect reality. This study provides a critique of broad-scale nutrient mass balances, with particular application to the fertiliser use of beef lot-feeding manure in Queensland.Mass balances completed at the district and farm scale were found to misrepresent actual manure management behaviour and potentially the risk of nutrient contamination of water resources. The difficulties of handling stockpile manure and concerns about soil compaction mean that manure is spread thickly over a few paddocks at a time and not evenly across a whole farm. Consequently, higher nutrient loads were applied to a single paddock less frequently than annually. This resulted in years with excess nitrogen, phosphorus, and potassium remaining in the soil profile. This conclusion was supported by evidence of significant nutrient movement in several of the soil profiles studied.Spreading manure is profitable, but maximum returns can be associated with increased risk of nutrient leaching relative to conventional inorganic fertiliser practices. Bio-economic simulations found this increased risk where manure was applied to supply crop nitrogen requirements (the practice of the case study farms, 200–5000 head lot-feeders).Thus, the use of broad-scale mass balances can be misleading because paddock management is spatially heterogeneous and this leads to increased local potential for nutrient loss. In response to the effect of spatial heterogeneity policy makers who intend to use mass balance techniques to estimate potential for nutrient contamination should apply these techniques conservatively.     

Analysis of organic compounds in coal gasification wastewater

A procedure for analysis of organic pollutants in coal gasification wastewater was developed, including a series extraction steps at different pH, followed by LC separation or resin adsorption, then analyzed by GC or GC/MS. More than 200 organic pollutants in 22 categories were determined. CH2CL2 extraction at NaHCO3 presence was used to separate carboxylic acids with phenolic compounds in aqueous. Derivatization with acetic anhydride was used for analyses of mono-, di-, poly-hydroxyl phenolic compounds. 21 mono-hydroxyl phenols and 13 di-hydroxyl phenols were determined from the coai gasification wastewater samples. Derivatization with BF3-CH3OH was used for analysis of carboxylic acid. 17 mono-carboxyl, 4 di-carboxyl acids and 6 aromatic acids were determined from coal gasification wastewater samples.     

A fetal cystic neck mass associated with maternal tuberous sclerosis. Case report and literature review

Tuberous sclerosis is a single gene autosomal-dominant disorder, characterized by multiple hamartoma formation. It shows a wide variability of expression. Prenatal diagnosis by means of a DNA or biochemical marker is not yet possible. Ultrasound offers the only way to detect possible antenatal hamartoma formation, which is most commonly found in the central nervous system, the renal system, and the heart. We report a case of fetal involvement that appears unique because of the unusual location of a tumour in the neck of the fetus.     

超临界流体色谱分析有机污染物

概述了超临界流体色谱的进展，特点、原理及影响超临界流体色谱测定的主要因素。介绍了超临界流体色谱与其他测定仪器的联用技术。列举了该技术在分析环境样品中有机污染物的应用。如分析有机氯、有机磷和氨基酸酯及农药的残留组分，多环芳烃，芳香烃等化合物。     

河流水质1号模型探讨

介绍了河流水质模型70年来的发展历程和目前存在的不足之处,论述了河流水质1号模型(RwQM1)的研究成果.河流水质1号模型从活性污泥模型ASM中发展而来,并推出了建立模型的决策化方法,其对生化反应模型的完善而成为河流水质模型发展的一个标准平台.本文重点介绍了其在生化反应模型方面的进展,并和QUAL2E做了比较.     

反相气相色谱法研究CPC-膨润土对VOCs的吸附作用

运用反相气相色谱法研究了20种VOCs在CPC-膨润土上的吸附平衡及吸附热．结果表明，CPC-膨润土对VOCs的吸附有较强选择性，吸附能力与有机物的分子量、分子结构、饱和蒸气压等物理化学性质有关，对苯系物和分子量较大的酯类和酮类等吸附能力较强．温度较低时，CPC-膨润土对VOCs的吸附能力较强，吸附热较大；吸附热与VOCs的沸点蒸发热相当，但比活性炭等常规吸附剂对VOCs的吸附热小。