应用改进密切值法进行地表水环境综合评价

针对密切值法应用中的实际问题,引入目标差值率和虚拟优点、劣点的概念,对密切值法进行了改进.将改进后的密切值法应用于地表水环境综合评价中,经实例分析表明,该方法概念清晰、计算简便实用,且从评价结果可获许多潜在的信息,是开展地表水流域水环境综合评价的一种有效的方法.     

11种有机磷农药对海洋微藻致毒效应的研究

通过研究不同盐度条件下１１种有机磷农药对扁藻的相对增长率和叶绿素ａ含量的影响，得到了Ｓ＝３０和Ｓ＝２０时的半数有效浓度，并比较其大小。盐度作为环境因子，影响到有机磷农药的毒性。研究发现，遥有机磷农药在低浓度时出现一定限度的促生长作用；容易进攻细胞膜的有机磷农药对扁藻的致毒性相对较强；此外，有机磷农药的毒性大小与其结构密切相关含有苯环结构的有机磷农药毒性大小不含有苯 有机磷农药的毒性。     

Effects of bifenthrin on Daphnia magna during chronic toxicity test and the recovery test

IntroductionWiththedevelopmentandapplicationofnewpesticide ,insecticidehasgreatlyreducedtheharmofpesttocrops .Bifenthrinisaneffectivepyrethroidinsecticideandacaricideagainstawiderangeofinsectpests ,anditisverypoisonoustomammal,aquatic .Thisinsecticideiswi…     

SBR法运行控制工艺研究进展

SBR法是一种具有独特的优点的废水生物处理工艺，但至今还没有一套公认的运行控制工艺，本文从SBR法的启动，充水时间及反应时间的确定，模糊控制，目标控制操作等几方面对SBR工艺的运行控制做了评述，并对其今后的研究方向做了展望。     

镀液循环流量对封闭循环电沉积Ni-SiC复合镀层的影响

目的 研究封闭式镀液循环装置中不同镀液循环流量对Ni-SiC复合镀层的影响规律,优化镀液循环流量参数.方法 以Q235管状工件为待镀基体,以添加SiC颗粒的改良瓦特镀液为母液,在自主研发的封闭式镀液循环电镀装置中以0.3、0.5、0.7 m3/h的镀液循环流量于管件内壁制备Ni-SiC复合镀层,通过SEM检测、XRD测试、硬度测试和摩擦磨损性能测试等手段,对各Ni-SiC复合镀层宏微观形貌、厚度、成分、结构、硬度和耐磨性进行分析研究.结果 在0.5 m3/h流量条件下,镀层厚度为32.98μm,SiC颗粒含量为15.37％,镀层晶粒尺寸和硬度分别为10.84 nm和704HK0.245,该条件下制备的Ni-SiC复合镀层具有最佳耐磨性,摩擦系数为0.41,体积磨损率仅2.83×10–5 mm3/Nm.结论 在不同镀液循环流量参数下,采用该封闭式循环电镀装置,均可制得均匀完整的Ni-SiC复合镀层.随镀液循环流量的升高,镀层厚度和SiC颗粒体积含量均降低,镀层颜色金属光泽增强,镀层晶粒尺寸先减小、后增大,镀层硬度则先升高、后降低.     

关于中国生活垃圾渗滤液排放标准的探讨

介绍了美国、德国、日本等国的渗滤液排放标准,并与中国现行的<生活垃圾填埋污染控制标准>(GB16889-1997)中的渗滤液排放标准相比较,指出了其存在的排放标准统一化、限值过于严格、控制项目不足等问题,并针对这些问题提出了相关的建议.     

低温高铁锰氨氮地下水两级生物净化快速启动

为了实现东北地区低温（5~6℃）高铁、锰、氨氮（TFe：9~15mg/L，Fe²⁺：6~12mg/L，NH₃-N：1.4~2.0mg/L，Mn²⁺：1.4~2.0mg/L）地下水的净化及解决同层净化中运行稳定性差、出水锰超标的问题，在水厂净化车间开展“两级曝气+两级过滤”工艺启动研究，采用差滤速和同滤速2种启动方式分别启动两级生物净化工艺.结果表明，2种启动方式分别在106，59d启动成功.同滤速启动可以有效的缩短两级生物净化的启动时间，铁、锰、氨氮去除负荷可达110.69，18.80，19.54g/（m²·h），沿程分析发现，铁在一级滤柱的60cm处即被去除至痕量；85.08%的氨氮在一级滤柱中去除，沿程各段去除均匀，14.92%的氨氮在二级滤柱中去除；锰的去除率和氧化活性去除区位受滤速及进水氨氮浓度影响较大，33.72%的锰在一级滤柱中去除，66.28%的锰在二级滤柱中去除，锰的去除仍然是滤池成熟的决定性因素.     

The safety of fetoscopy: (I). Effect of umbilical vessel puncture on the fetal heart rate and cord histology

The fetal heart rate (FHR) was continuously monitored during 42 umbilical vessel punctures performed at the placental insertion of the cord in 24 diagnostic fetoscopies in which pure fetal blood was obtained. In only one patient did a deceleration first appear during puncture and aspiration of fetal blood. In two patients decelerations preceded fetoscopy and in two others they began during the fetoscopy but before puncture of an umbilical vessel. In 19 patients, the FHR did not change at all during the procedure. Fetal haemorrhage after sampling was either absent or minimal. Six pregnancies were terminated because a positive diagnosis had been made and 18 healthy babies were born. Umbilical cords were examined after 7 terminations of pregnancy and after 6 deliveries. In the former group the puncture could just be seen with the naked eye and the needle track was demonstrated histologically in 6. No traces of the puncture or other abnormalities were found in the cords after delivery. Fetal blood sampling from umbilical cord vessels, particularly at the placental insertion of the cord, is the technique of choice since pure fetal blood can be obtained without increasing the risk of fetoscopy.     

Intra-specific variations of two Leymus chinensis divergence populations in Songnen Plain, northeast China

Population demography, seed production, biomassallocation, net photosynthesis and transpiration of two Leymus chinensis divergence populations and between two years in Songnenplain, northeast China were compared. Strong differences betweenthe dry 1997 and moist 1998 occurred in vegetative shoot and sexualshoot densities, sexual differentiation and tiller densities, aswell as in the lengths of inflorescence, seed numbers perinflorescence, seed weights and biomass allocation in eachpopulation respectively (P<0.01). While strong differences betweenthe two populations occurred in vegetative shoot densities, sexualshoot densities, sexual differentiation and seed weights in eachyear (P<0.01). The differences between the two populations intiller densities and in biomass allocation to sexual shoots were significant (P<0.05). But there were no significant differences between the two populations in the lengths of inflorescence, seed numbers per inflorescence and biomass allocation to rhizomes and vegetative shoots (P>0.05). Excepting the transpiration rate in the early June, the differences between the two populations in net photosynthesis and transpiration rate of vegetative shoots and sexual shoots were strongly significant in the early June and July respectively (P<0.01). Relative stable variations in population demography and physiological traits between the two populations indicated that they are divergently in the Songnen Plain.     

Effect of leachate recycling and inoculation on the biochemical characteristics of municipal refuse in landfill bioreactors

Activity development of key groups of enzymes involved in municipal refuse decomposition was measured in laboratory landfill bioreactors with and without leachate recycling and inoculation for about 210 days.The results showed that the enzymes(amylase,protease,cellulase,lipase and pectinase)were present in fresh refuse but at low values and positively affected by leachate recycling and refuse inoculation.The total average of cellulase activity in digesters D3 operated with leachate recycling but no inoculation,D4 and D5 operated with leachate recyling and inoculation was much higher than that in digesters D1 and D2 without leachate recycling and inoculation by 88%-127%,117%-162%and 64%-98%.The total average of protease activity was higher in digester D4 than that in digesters D1,D2,D3and D5 by 63%,39%,24%and 24%,respectively,and the positive effect of leachate recycling and inoculation on protease activity of landfilled refuse mainly was at the first two months.The total average of amylase activity was higher in digesters D3,D4 and D5 than that in digesters D1 and D2 by 83%-132%,96%-148%and 81%-129%.During the early phase of incubation,the stimulatory effect of inoculation on lipase activity was measured,but refuse moisture was the main factor affecting lipase activity of landfilled refuse.The inoculation,initial and continuous inoculation of microorganisms existing in leachate,was the mainly stimulatory factor affecting pectinase activity of landfilled refuse.