表面活性剂对分枝杆菌KR2生长的影响

研究了表面活性剂的浓度、离子类型和分子结构等对分枝杆菌KR2菌株生长的影响。结果表明，一些表面活性剂在低浓度时可以促进分枝杆菌KR2的生长，高浓度时则会抑制KR2菌株的生长。表面活性剂的离子类型对KR2菌株生长抑制作用的顺序为：阳离子活性剂TDTMA＞阴离子表面活性剂LAS＞非离子表面活性剂Tween80。表面活性剂的直链长度对KR2菌株生长的影响为：直链越短，对分枝杆菌KR2菌株生长的抑制作用越大。     

环境工程设计质量保障体系探讨

以污水处理工程为例，阐明环境工程设计质量保障体系的构成，概述设计原则以及每一设计步骤所需注意的问题，对验证、确保设计质量的后续工作过程作了简要的介绍。     

Analysis of relationship between economic growth and environment in Benxi Shiqiaozi Development Zone

ＡｎａｌｙｓｉｓｏｆｒｅｌａｔｉｏｎｓｈｉｐｂｅｔｗｅｅｎｅｃｏｎｏｍｉｃｇｒｏｗｔｈａｎｄｅｎｖｉｒｏｎｍｅｎｔｉｎＢｅｎｘｉＳｈｉｑｉａｏｚｉＤｅｖｅｌｏｐｍｅｎｔＺｏｎｅ￥ＬｉＢｉｎ；ＲｕＪｉａｎｇ；ＹｅＷｅｎｈｕ；ＸｕＹｕｎｌｉｎ（Ｃｅｎｔｅ...     

Characteristics of phosphorus chemistry and its geographical distribution in the Haihe River valley,North China

ＣｈａｒａｃｔｅｒｉｓｔｉｃｓｏｆｐｈｏｓｐｈｏｒｕｓｃｈｅｍｉｓｔｒｙａｎｄｉｔｓｇｅｏｇｒａｐｈｉｃａｌｄｉｓｔｒｉｂｕｔｉｏｎｉｎｔｈｅＨａｉｈｅＲｉｖｅｒｖａｌｌｅｙ，ＮｏｒｔｈＣｈｉｎａＪｉａｎｇＧａｏｍｉｎｇ；ＨｕａｎｇＹｉｎｘｉａｏ；Ｌ...     

油田采出水处理技术与发展趋势研究

油田采出水具有水量大,水质复杂,处理难度高等一系列特点,因此寻求合适的处理技术一直是油田面临的主要问题.针对油田采出水的产生和特点,介绍了近年来研究较多的油田采出水处理技术,主要包括分离技术、过滤技术、膜技术、气浮技术、吸附技术等物理法;盐析技术、混凝沉淀技术、化学氧化技术、电化学处理技术等化学和物理化学法;活性污泥技术、生物滤池技术等生物法,并概述了油田采出水处理技术的最新研究成果.通过对现有技术分析,总结出当前油田采出水处理中存在的问题,并对存在的处理难点做出了分析,提出了油田采出水处理技术的发展趋势.     

光化学反应的环境效应

光化学反应具有良好的环境效应，本文概述了有机合成和环境化学中光化学反应对环境的影响。     

Amniotic fluid alpha-fetoprotein levels and prenatal diagnosis of autosomal trisomies

Pregnancies with fetal trisomy 21 have been associated with low amniotic fluid alpha-fetoprotein levels (AFAFP). This observation led to the suggestion that low AFAFP levels be used as a criterion for completion of a chromosomal analysis in patients who are not otherwise at increased risk for a fetal chromosome abnormality and in whom karyotyping might not have been completed for economic reasons. In order to assess the usefulness of such criteria, we reviewed the AFAFP levels of 90 cases of fetal trisomy 21, 23 cases of trisomy 18, and 10 cases of trisomy 13. These were compared with 2400 control samples with normal chromosome constitution. AFAFP levels were generally lower in pregnancies with trisomy 21, showing a median value of 0·72 MoM. However, 40 per cent of the trisomy 21 samples had AFAFP values greater than 0·8 MoM and 20 per cent were over 1·0 MoM. These data imply that over 50 per cent of Down syndrome cases might have been missed using a cut-off level of 0·70 MoM for completion of chromosome analysis. Using a higher cut-off level will leave only a small percentage of samples unkaryotyped. The distribution of AFP levels in trisomy 13 and 18 is no different from controls; we therefore believe that fetal karyotyping should be completed in every amniotic fluid sample obtained.     

湿法烟气脱硫应用中的几个问题探讨

对火电厂应用石灰石 石膏法烟气脱硫中遇到的几个实际问题进行分析和讨论 ,重点讨论分析了湿法烟气脱硫和烟气温度、烟气抬升高度、烟气扩散的关系 ,并分析了湿法烟气脱硫对烟囱产生的腐蚀影响     

垃圾渗滤液的混疑处理实验研究

用聚合氯化铝(PAC)．聚丙烯酰胺(PAM)．复合混凝剂(90％PAC 10％PAM)及试剂A(一种壳聚糖)等4种混凝剂在不同pH及不同投加量的情况下．对垃圾渗滤液COD的去除效果进行了比较分析。实验结果表明。复合混凝剂及试剂A的处理效果明显优于PACPAM。在pH值5.5和8时。复合混凝剂投加量为400mg／L时。COD的去除率分别为38．63％和37．84％：试剂A在pH为8．投加量为100mg／L时。对COD的去除率达到39．85％。     

Initial Homotypic Cell Pair Adhesion in Regenerating Hydra Facilitates Subsequent Adhesion of Homotypic Cells

 In Hydra vulgaris at the level of dissociated single cells endodermal cells adhere to each other more readily than to ectodermal cells at the initial adhesion. The time required for adhesion to occur between two adjacent cells is shorter for both endodermal and ectodermal homotypic cell adhesions once the initial adhesion of the first pair of cells has been established. It is confirmed that contact of an aggregated pair with additional homotypic cells facilitates the occurrence of homotypic adhesions; heterotypic adhesions are discouraged. This suggests that adhesion of homotypic cells contributes to an increased readiness for subsequent homotypic cells to adhere. Received: 25 August 1999 / Accepted in revised form: 11 January 2000