轴承生产废水处理工艺的选择与实践

采用絮凝气浮 过滤工艺处理轴承生产废水。工程实践表明,该工艺处理效果稳定、耐冲击负荷、工艺组合合理。预处理后的废水经气浮 过滤工艺处理后,COD、SS、油的去除率分别为80.62%～84.31%、81.00%～84.39%、89.37%～96.45%,出水完全能达到排放标准。     

烧结砖生产中氟的逸出及钙基废渣固氟特性研究

砖坯烧制过程中，氟逸出的初始温度约为600℃，大部分氟在约800℃至砖坯发生明显烧结的温度内逸出，以CaO含量高的粘土原料制砖，氟逸出量相对较少。在此基础上，提出在制砖原料中添加适量钙基废渣抑制氟的逸出，并进行了详细的实验室和工业性试验；结果表明，在适宜添加量下，存氟率由约25％增至70％以下，且不影响砖制品质量。     

十六位DAC转换器的研制

十六位DAC转换器是为MAT系列同位素质谱仪磁场控制关键部件DAC73K模块进行国产化而设计的,它能够与八位、或十六位微机相兼容,具有精度高、准确度好、温飘小等特点,它的研制成功不仅加速了MAT系列质谱仪国产化进程,而且在其它自动控制系统中得到广泛应用.     

Nature and frequency of chromosomal abnormalities in pregnancies with abnormal ultrasound findings: An analysis of 117 cases with review of the literature

During a 7-year period, 117 fetal karyotypes were available from 131 genetic amniocenteses. These procedures were performed between 14 and 37 weeks' gestation for the following abnormal ultrasound findings: (1) intrauterine growth retardation (IUGR)—61 cases; (2) fetal malformation—71 cases; and (3) amniotic fluid volume (AFV) abnormality—60 cases. Chromosomal abnormalities were identified in 19 cases (16.2 per cent). Aneuploidy was 2.5 times as frequent in the presence of malformations than in their absence. No correlation was demonstrated between specific fetal malformations and specific chromosomal abnormalities. Aneuploidy was also twice as frequent in the presence of symmetrical IUGR than in its absence. No chromosomal abnormalities were found among eight cases of asymmetrical IUGR. Four cases of aneuploidy presented with isolated IUGR, three of these involving the X chromosome. The frequency of aneuploidy was the same with or without abnormalities of AFV (14.3 versus 16.4 per cent). No chromosomal abnormality was found associated with isolated AFV abnormalities.