Detecting neural tube defects by amniocentesis between 11 and 15 weeks' gestation

Forty-two open neural tube defects (NTDs) were identified in our series of 7440 amniocenteses tested between 11 and 15 weeks of gestation. Using a cut-off of ≥2.0 MOM, the detection rate for open NTDs was 95 per cent; 100 per cent each for anencephaly and spina bifida; and 78 per cent for encephalocele. Two encephaloceles had AFP levels less than 2.0 MOM and negative AChEs. Thirty-four (81 per cent) of these NTDs were tested between 13 and 15 weeks and 8 (19 per cent) before 13 weeks. There were 0.6 per cent false positives by AFP (excluding serious abnormalities and fetal death) and 0.1 per cent after AChE. The likelihood of an open NTD after an elevated AFP (≥2.0 MOM) was 24 and 77 per cent for any serious abnormality. These results, when combined with an earlier study, indicate that amniotic fluid AFP appears to be as sensitive a test for open NTDs between 13 and 15 weeks as between 16 and 20 weeks. Additional experience is necessary to determine this before 13 weeks.     

推导保护水生环境质量标准的方法研究

综述了美国及欧洲一些国家推导水生环境质量标准的方法研究。对水生环境质量标准包括的水质标准，底泥标准，人类和野生生物标准进行了分别叙述，详细讨论了推导水生环境质量标准的数据要求和计算方法。     

云南安宁工业区工业经济-水资源-水污染系统仿真模型及策略分析

水资源短缺和水污染是安宁工业区经济发展的重要限制因素。本文将该工业区分解为3个子区,应用系统动态学方法,建立多区相关的工业经济-水资源-水污染系统仿真模型,分别对各子区1985至2000年的工业产值、工业用水差距和水质进行多方案预测。在子区域综合的基础上,结合多级决策树法,筛选出安宁工业区协调工业经济、水资源和水质之间关系的最佳方案。     

水解酸化─厌氧─好氧─混凝─吸附工艺处理洁霉素生产丁提高浓度有机废水

采用水解酸化厌氧好氧混凝吸附工艺处理洁霉素生产丁提高浓度有机废水，工程实践表明，ＣＯＤＣｒ和ＢＯＤ５去除率在９９％以上，所排废水各项指标达到国家排放标准。     

The curve of ion exchange ratio(%)-pH of the interaction between suspended particles with Cd(II) in the Yellow River

The curve of ion exchange ratio(%)-pH of the interactionbetween suspended particles with Cd(II) in the Yellow River wasstudied. The effects of lysine on this curve have been alsoinvestigated. The results showed that (1) Cadmium in Cd(OH)+ formin the suspended particles exchanges with the cations.The exchangeratio of Cd2+ is nearly at its greatest value in the range of pH(8.0-8.5) in natural aquatic system; (2) Ion exchange ratiodecreases as the concentration of Cd2+ raises from 8.9×10-6 mol/L to 2x8.9 x 10-6mol/L; (3) At the lysine concentration of 6.8x10-6 mol/L, it can promote the ion exchange ratio; (4) Adsorption of thesuspended particles to cadmium is weaker in seawater and Jin ShaRiver than in the Yellow River.     

油品储运过程挥发损耗测算与分析

通过对燕化公司油品储运情况的调查，测算其油品储运过程中的挥发损耗，并提出了有关的防治措施。     

长江中下游海相三叠系膏盐层与铜(金)、铁矿床

长江中下游海相三叠系膏盖层中含有很大比例的大、中型铜（金）、铁、多金属矿床。膏盐层不仅是铜（金）、铁矿床的主要赋矿层位之一，而且是部分成矿金属的矿源层；膏盐层还为燕山期岩浆提供部分钠质、钾质及挥发组分，影响岩浆演化的方向，改变了含矿流体的性质；另外，从岩体和矿床中金属硫化物中流同位素重硫成分的增高，说明在成者、成矿过程中，膏盐层是硫的供应者之一。因此膏盐层与铜（金）、铁、多金属矿床之间存在着特殊的成因联系。     

安徽月山地区闪长岩类地质地球化学研究

安徽月山地区是长江中下游地区的重要成岩-成矿区段。本文通过岩石学、岩石化学和同位素地球化学等方面的研究，探讨和阐明了月山地区闪长岩类的形成环境、物质来源、源区特征、岩浆形成与演化机理等。     

反硝化在土壤及地下水中的净化作用

综述了土壤及地下水系统中反硝化作用的研究进展，详细地介绍了反硝化作用的原理和机制，用以防治地表水和地下水的污染。     

机车检修污水处理回用设施实例分析

机车清洗污水经撇油、酸碱中和、气浮、过滤、活性碳吸附等工艺流程的处理后,进行全封闭循环,再用于清洗机车,合理选择污水处理工艺流程是确保处理后的污水能否经济、合理回用的关键.