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31.
物理化学预处理与膜分离技术的应用 总被引:1,自引:0,他引:1
将物理化学预处理与膜分离技术深度处理结合应用于工业废水处理,可使其中的Cr6+<0.5mg/l,Zn2+<20mg/l,pH6~9。用膜分离技术处理造纸废水可回收其中的木质素和糖份,回收率均为60%左右。 相似文献
32.
苏国胜 《安全.健康和环境》2003,3(4):20-22
通过对网上培训的介绍及网上教育系统的分析,提出了网上安全培训系统的发展方向,对网上职业安全教育培训系统建立和实现形式提出了看法。 相似文献
33.
水中溶解氧快速测试管的研制 总被引:1,自引:0,他引:1
水中溶解氧不稳定,需要现场即时测定。本文旨在研究现场快速测定水中的溶解氧。本研究运用比色分析的朗伯——比尔定律和真空工艺设计,将复杂繁琐的实验室测试方法和操作程序有机的融合在测试管中。该测试管能快速、简便地测定水中的溶解氧。测定范围为0.01—12mg/1,检出限为0.0lmg/1。常规法测定时间需要3—5小时,而该测试管法仅需1—2分钟,分析成本也大为降低。 相似文献
34.
常登刚 《安全.健康和环境》2002,2(3):20-21
对搞好安全生产必须依靠安全科技进行了论述.提出了在安全工作中必须运用科技手段的必要性和必须正视的几个现实问题. 相似文献
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37.
中国多样的生态农业技术体系 总被引:21,自引:1,他引:21
中国生态农业的技术体系主要包括①农业环境综合整治技术;②农业资源的保护与增殖技术;③小流域综合利用技术;④立体种养技术;⑤庭院资源综合利用技术;⑥再生能源利用技术;⑦农业副产物再利用技术;⑧有害生物的综合防治技术。中国生态农业的技术体系继承了中国传统农业的精华,充分利用资源,合理保护资源,有效地连接农业的不同组分。文章介绍了中国近10多年来成功应用这些技术的典型例子,并且指出这将有利于中国实践"21世纪议程"和粮农组织的"持续农业和农村发展宣言"。 相似文献
38.
Joe Leigh Simpson James L. Mills George G. Rhoads George C. Cunningham Howard J. Hoffman Mary R. Conley 《黑龙江环境通报》1991,11(8):641-648
No clear answer concerning whether multivitamin/folate supplementation prevents neural tube defects (NTDs) is provided by three studies in the United States. All these studies are occurrence in nature, no recurrence studies having been conducted. The Atlanta Birth Defects Study is subject to pronounced memory and recall biases, the length between event and interview being as long as 16 years. In a second study (Boston University), objections can be raised to certain aspects of the experimental design, and the claim that 22 per cent of women started vitamins sufficiently early after pregnancy diagnosis to influence NTD formation is suspicious. Our NICHD case control study of 541 women in California and Illinois revealed no evidence for multivitamins or folic acid preventing NTDs. U.S. public policy-makers face difficulties in applying results of recurrence or occurrence studies in high-risk areas to low-risk areas in the U.S. 相似文献
39.
A survey was carried out to determine the effect of prenatal screening and therapeutic abortion on births in 1985 with anencephaly and spina bifida in England and Wales. Maternal serum alpha-fetoprotein tests were done on 399 288 women (60 per cent of pregnant women): 4 per cent were reported as being screen-positive and 1 per cent had an amniocentesis. An estimated 534 pregnancies associated with anencephaly were terminated and an estimated 445 pregnancies associated with spina bifida (but without anencephaly) were terminated. Most (63 per cent) of the anencephalic pregnancies were first suspected from an ultrasound examination; 57 per cent of the spina bifida pregnancies were first suspected from a positive maternal serum alpha-fetoprotein test, 35 per cent by ultrasound, and the remaining 8 per cent by other means. The birth prevalence of anencephaly declined by 94 per cent between 1964–1972 and 1985, but when the terminations of pregnancy on account of having a fetus with anencephaly are added to the births the decline in prevalence was only 50 per cent. The birth prevalence of spina bifida declined by 68 per cent over the same period but when the terminations were added to the births the decline in prevalence was only 32 per cent. Among births with anencephaly 66 per cent had had no screening or diagnostic tests in early pregnancy, but in those that did nearly all were positive–usually in twin pregnancies where one fetus was affected but not the other. Among births with spina bifida, 48 per cent had no tests and in those that did the results were mainly negative. We conclude that in order to monitor adequately the national screening programme for anencephaly and spina bifida a special neural tube defects register should be formed. 相似文献
40.
The aim of this study was to determine whether there is increased leakage of neuron-specific enolase (NSE) and S-100 protein into amniotic fluid in pregnancies with neural tube defects, since both these proteins are produced by neural tissue, and to compare the value of these substances for detecting such defects with that of the more conventional techniques of alpha-fetoprotein (AFP) and acetylcholinesterase (AChE) gel electrophoresis. Amniotic samples from 25 mid-pregnancies (15–17 weeks' gestation) with neural tube defects (14 with open spina bifida and 11 with anencephaly) and from seven mid-pregnancies with abdominal wall defects were compared with a control material consisting of 80 amniotic fluid samples from 80 consecutive mid-pregnancy amniocenteses, with normal karyotypes and AFP concentrations. All of the above cases of abnormalities were primarily detected through increased AFP levels in the amniotic fluid. Amniotic fluid samples from 13 pregnancies with fetuses with autosomal chromosomal abnormalities and seven amniotic fluid samples contaminated with blood were also included in the investigation. It is concluded from the results that the conventional AFP assay combined with AChE gel electrophoresis is the best method for screening amniotic fluid for neural tube defects and defects of the abdominal wall. Neither NSE nor S-100 assay alone proved to be superior for the detection of these cases in mid-trimester amniotic fluid. The S-100 assay, however, could give additional information in cases where AChE gel electrophoresis is not decisive; for example, in samples contaminated with blood. 相似文献