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51.
SBR法运行控制工艺研究进展 总被引:3,自引:0,他引:3
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。 相似文献
52.
Compounds in the atmosphere contaminate samples of groundwater. An inexpensive and simple method for collecting groundwater samples is developed to prevent contamination when the background concentration of contaminants is high. This new design of groundwater sampling device involves a glass sampling bottle with a Teflon-lined valve at each end. A cleaned and dried sampling bottle was connected to a low flow-rate peristaltic pump with Teflon tubing and was filled with water. No headspace volume was remained in the sampling bottle. The sample bottle was then packed in a PVC bag to prevent the target component from infiltrating into the water sample through the valves. In this study, groundwater was sampled at six wells using both the conventional method and the improved method. The analysis of trichlorofluoromethane( CFC-11 ) concentrations at these six wells indicates that all the groundwater samples obtained by the conventional sampling method were contaminated by CFC-11 from the atmosphere. The improved sampling method greatly eliminated the problems of contamination, preservation and quantitative analysis of natural water. 相似文献
53.
G. A. Hackett Dr. J. H. Smith M. T. Rebello C. T. H. Gray D. E. Rooney R. W. Beard F. E. Loeffler D. V. Coleman 《黑龙江环境通报》1991,11(5):311-315
Early arnniocentesis between 11 and 14 weeks' gestation was offered to 110 women at risk of a chromosomally abnormal fetus due to maternal age. Four were found to be unsuitable for the procedure, and 106 early amniocenteses were performed. In 102 cases, clear amniotic fluid was obtained with a single tap. There were two dry taps and two bloodstained tapis; sampling was repeated in three of these cases before 15 weeks. In the fourth case, placental biopsy was performed at 16 weeks. Thus, we were able to obtain a satisfactory sample in all but three cases(2.8 percent). Karyotyping of cells harvested from the early amniotic fluid samples was successful in all the 105 cases. Cell culture from the initial samples revealed a normal karyotype in 99 cases, two balanced translocations, two tetraploid karyotypes, and two cases of pseudomosaicism. Of the 105 pregnancies successfully sampled, there have been two losses to date (1–8 per cent). Two further patients presented with premature rupture of membranes, both pregnancies having successful outcomes. Sixty-two babies have delivered to date, with four congenital anomalies. There were no respiratory problems. Twenty-nine pregnancies are continuing without known complications, and details are not yet available on the remaining 12. The results indicate that early arnniocentesis may replace the traditional test at 15–17 weeks. 相似文献
54.
The first prenatal diagnosis of Pallister-Killian syndrome by chorionic villus sampling is presented. Fetal hydrops was noted on ultrasound in early pregnancy, and the karyotype revealed isochromosome 12p mosaicism. 相似文献
55.
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. 相似文献
56.
57.
浅析环保思想在企业CI战略中的应用和作用 总被引:1,自引:0,他引:1
随着我国社会主义市场经济体制的确立,以市场战略为导向的CI逐步在中国兴起。文中分析了环保思想在企业口战略中的应用和作用。 相似文献
58.
Andrew D. Dorfmann Jeane Perszyk Patricia Robinson Susan H. Black Joseph D. Schulman 《黑龙江环境通报》1992,12(11):899-902
This paper reports eight cases of non-mosaic, rare, and typically lethal trisomies diagnosed in chorionic villi and not confirmed by amniocentesis. Four cases were 47,XX, + 16; two cases were 47,XX, +2; one was 47,XX, + 12; and one was 47,XY, +7. There have been no known complications in any of these gestations. These eight cases were found in a series of approximately 12 000 samples processed in our laboratory (0.07 per cent). We conclude that (1) rare non-mosaic trisomy not reflecting the fetal condition is an occasional source of diagnostic ambiguity in chorionic villus sampling; and (2) when encountered, a follow-up amniocentesis should be recommended to the patient to confirm or rule out the abnormality. We propose the term ‘confined placental abnormality’ to describe non-mosaic trisomies and other related abnormalities found only in chorionic tissue. 相似文献
59.
促进经济与环境协调发展的基本战略 总被引:6,自引:2,他引:6
从与国际先进大城市在环境与经济协调发展方面的比较中,分析上海目前的环境与经济协调发展的状况和面临的主要环境问题。根据上海的城市发展战略的目标和要求,提出了要遵循生态发展规律,以保持城市水资源和改善大气环境质量为重点,优先发展城市基础设施和环境建设,加快能源结构的改善和产业结构的调整,在发展经济的同时不断增加城市生存环境建设投入,以实现已确定的跨世纪的环境保护总目标,促进环境与经济的协调发展的7方面 相似文献
60.
山西矿区矸石山复垦种植施肥策略 总被引:8,自引:1,他引:8
围绕煤矸石缺乏有机活性物质及有效养分的问题,在矸石山复垦种植时,对施肥作了试验研究。结果表明,煤矸石风化物由于吸附性能低,保肥性差,所以施用化肥时一次用量不宜过大。并从降低复垦的投资与难度以及尽快建立一个可自我维持生长的植被出发,提出了矸石山复垦种植时化肥与污泥配合施用的施肥策略,并对污泥的施用效果做了研究。 相似文献