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1.
本系统基于气体浓度光学分析方法理论朗伯-比尔(Lambert-Beer)定律、光谱气体检测技术开发,实现了对煤矿火灾与瓦斯灾害超前预警、灾害产生的有毒有害气体实时监测和煤矿环境气体爆炸危险性辨识,对于煤矿灾害防治、救灾过程中杜绝次生灾害,保障煤矿工人及救护队员的生命安全,促进煤矿安全生产具有重要意义。 相似文献
2.
In order to study a new leak detection and location method for oil and natural gas pipelines based on acoustic waves, the propagation model is established and modified. Firstly, the propagation law in theory is obtained by analyzing the damping impact factors which cause the attenuation. Then, the dominant-energy frequency bands of leakage acoustic waves are obtained through experiments by wavelet transform analysis. Thirdly, the actual propagation model is modified by the correction factor based on the dominant-energy frequency bands. Then a new leak detection and location method is proposed based on the propagation law which is validated by the experiments for oil pipelines. Finally, the conclusions and the method are applied to the gas pipelines in experiments. The results indicate: the modified propagation model can be established by the experimental method; the new leak location method is effective and can be applied to both oil and gas pipelines and it has advantages over the traditional location method based on the velocity and the time difference. Conclusions can be drawn that the new leak detection and location method can effectively and accurately detect and locate the leakages in oil and natural gas pipelines. 相似文献
3.
As part of the Medical Research Council randomized trial of vitamin supplementation in the prevention of neural tube defects (NTDs), maternal serum alpha-fetoprotein (AFP) was available for 19 NTD pregnancies. Each of these was matched with four unaffected controls, by maternal age, participating centre, and duration of sample storage. The samples came from women whose gestational age ranged from 6 to 14 completed weeks. The median AFP level in the affected pregnancies was 1·2 multiples of the median value in unaffected pregnancies of the same gestational age (95 per cent confidence interval (CI) 0·83–1·59). This confirmed the view that serum AFP measurement is of no practical value in the detection of NTDs in the first trimester of pregnancy. The study also showed that folic acid supplementation, used as a method of preventing NTDs, had no effect on the concentrations of maternal serum AFP up to 14 weeks of pregnancy. 相似文献
4.
涡凹气浮机在炼油污水处理中的应用 总被引:3,自引:0,他引:3
陈长顺 《石油化工环境保护》2004,27(4):21-22,49
对涡凹气浮机在炼油污水气浮工艺的改造的应用进行了总结,改造后该气浮机具有投资省、运行费用低、操作维护简单、工作效率高等优点,且运行稳定,效果比较理想,应用前景十分广阔。 相似文献
5.
高炉瓦斯泥的回收与利用 总被引:7,自引:1,他引:7
通过对济钢高炉瓦斯泥进行分离回收与综合利用的系统试验研究,作者推荐采用浮—重联合流程分离回收其中的炭和铁。试验获得如下指标:炭精矿品位80%,回收率50%;铁精矿品位60%,回收率45%;次铁精矿品位45%,回收率11.5%。经济和社会效益明显。 相似文献
6.
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
7.
8.
旋流板塔及其在废气处理中的应用 总被引:4,自引:2,他引:4
简述了旋流板塔原理、结构、设计参数,并列举了该塔在NOx、有机废气、HCl、燃油炉烟等方面治理工程应用实例。 相似文献
9.
Howard S. Cuckle 《黑龙江环境通报》1983,3(4):287-289
Data from 280 sibships in three published series were used to see if the increased risk of neural tube defect (NTD) associated with having had a miscarriage in the immediately preceding pregnancy was also found in women with a previous affected pregnancy. A statistically significant relative risk of 4.0 (2-tail P=0.0111, Fisher exact test) was found among such women, and this could not be accounted for by the effect of parity or of a history of miscarriage in general. The finding may be useful when counselling patients. 相似文献
10.
Wu Rui Li Guangyi Zhang Zongyi Ren Yulong Han Weijian 《Frontiers of Environmental Science & Engineering in China》2007,1(3):292-298
Road transport produces significant amounts of emissions by using crude oil as the primary energy source. A reduction of emissions
can be achieved by implementing alternative fuel chains. The objective of this study is to carry out an economic, environmental
and energy (EEE) life cycle study on natural gas-based automotive fuels with conventional gasoline in an abundant region of
China. A set of indices of four fuels/vehicle systems on the basis of life cycle are assessed in terms of impact of EEE, in
which natural gas produces compressed natural gas (CNG), methanol, dimethylether (DME) and Fischer Tropsch diesel (FTD). The
study included fuel production, vehicle production, vehicle operation, infrastructure and vehicle end of life as a system
for each fuel/vehicle system. A generic gasoline fueled car is used as a baseline. Data have been reviewed and modified based
on the best knowledge available to Chongqing local sources. Results indicated that when we could not change electric and hydrogen
fuel cell vehicles into commercial vehicles on a large scale, direct use of CNG in a dedicated or bi-fuel vehicle is an economical
choice for the region which is most energy efficient and more environmental friendly. The study can be used to support decisions
on how natural gas resources can best be utilized as a fuel/energy resource for automobiles, and what issues need to be resolved
in Chongqing. The models and approaches for this study can be applied to other regions of China as long as all the assumptions
are well defined and modified to find a substitute automotive energy source and establish an energy policy in a specific region. 相似文献