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801.
碳酸盐岩红土中氧化铁矿物表面化学特征及其吸附机理研究   总被引:17,自引:1,他引:17  
应用XPS技术,首次较系统地研究了碳酸盐岩红土中氧化铁矿物表面化学特征及其吸附机理,氧公铁矿物表面的XPS分析表明,矿物表面和整体之间在化学成分,状态和结构等方面存在明显差异,矿物表面的这种非均匀性特征是其表面化学反应的重要动力学起因。  相似文献   
802.
The 2872 second trimester amniocenteses followed by amniotic alphafetoprotein (AFP) estimations carried out in South Wales between 1973 and 1981 on women known to be at increased risk for neural tube defect (NTD) and those who had a raised serum AFP level in an NTD screening programme led to the identification of 78 pregnancies of a fetus with anen-cephalus, 61 with ‘open’ spina bifida, 8 with gastroschisis, 3 with exomphalos, 2 with encephalo-cele and 6 with chromosome abnormality. Pregnancies of fetuses having 4 potentially identifiable NTDs were missed because of an equivocal AFP level and there were two false positive results leading to the termination of one normal fetus. It is emphasized that both the latter problems of one normal fetus. It is emphasized that both the latter problems would not have occurred had gel-electrophoresis for isoenzymes of acetyl cholinesterase been available. Follow-up of pregnancies showed that 7 children with ‘closed’ NTD and 3 with congenital hydrocephalus were born. The anencephalics and the ‘open’ spina bifidas had a more florid lesion than is usual at term. Nearly all the spina bifidas were associated with hydrocephalus, often severe and with an obvious Arnold-Chiari malformation. All but 13 had leg or back deformation or malformations in other systems, mostly in the renal tract.  相似文献   
803.
对高温合金GH4169管材挤压成形进行了工艺研究.确定了GH1140管材挤压成形工艺参数,分析了GH4169管材挤压力能参数变化规律.分析了管材挤压对组织性能的影响。研究结果发现,GH4169管材挤压成形时必须严格控制坯料温度、模具预热温度、润滑方式、挤压速度、挤压比等工艺参数。  相似文献   
804.
饮食业油烟气快速检测-检气管法   总被引:5,自引:0,他引:5  
胡敏  张健 《上海环境科学》2003,22(11):840-843
针对GB18483—2001附录A《饮食业油烟采样方法及分析方法》在执法成本与执法手段上的局限性,提出了替代的饮食业油烟气快速检测——检气管法。通过对检气管法原理.方法可行性,经济成本的分析,认为利用检气管,通过该管内的油烟气使显色层显色。与标准色列进行比较.可以快速定性判别油烟气的浓度达标情况。检气管法较适用于低浓度(1~5mg/m^3)油烟气的检测判别,对排放标准2mg/m^3的油烟浓度能够给予判别是否超标或达标。  相似文献   
805.
A method for immunological detection of acetylcholinesterase (AChE) and cholinesterase (ChE) in amniotic fluid is described. By addition of a small amount of antihuman-erythrocyte membrane antibody or anti-pseudocholinesterase antibody to the sample before electrophoresis the two esterase bands on polyacrylamide gel (PAG) can be absorbed away. Similar staining results can also be obtained by specific inhibition of the two esterases with either BW 284C51 (AChE inhibitor) or Lysivane (ChE inhibitor). In cases with a faint AChE band and in cases with blood contamination the immune absorption technique makes interpretation easier. Nearly identical staining results have been obtained by the immune absorption technique and the inhibition technique in the following samples with an AChE band: 34 samples from pregnancies with severe fetal malformation or intrauterine death (2 cases), 4 fetal serum samples, 4 samples of cerebrospinal fluid, 4 samples of fetal erythrolysate and 4 samples of adult erythrolysate. It can be concluded that an antibody prepared against erythrocyte AChE cross-reacts with AChE in cerebrospinal fluid, and that this antibody can be used for demonstration of AChE in amniotic fluid.  相似文献   
806.
含铁酸性矿井水治理及工程应用   总被引:1,自引:0,他引:1  
含铁酸性矿井水是矿井外排水中的一种污染及危害极大的废水,采用传统处理虽能达到中和的目的,但除铁效果不甚理想,出水水质不稳定、易返色。本文针对含铁酸性矿井水的水质特征和治理中存在的主要问题,提出了一种新的净化技术,即两级综合法处理含铁酸性矿井水,不仅能同时达到中和、除铁的目的,而且出水水质完全达到一级排放标准,且出水24h后不返色,该技术在工程中得到了成功的应用。  相似文献   
807.
研究对玻璃模具用D型石墨铸铁的化学成分进行了合理设计和优选。结果表明,显微组织、抗氧化、抗生长和热疲劳抗力等性能,均有显著的改善和提高。经工业性试验,模具的寿命成倍提高。  相似文献   
808.
The sonographic diagnosis of fetal neural tube defects (NTDs) has been enhanced by the recognition of associated brain and skull anomalies. Previous reports have found these anomalies to be accurate in predicting spina bifida after 16 weeks' gestation, and an inverse correlation was suggested between the presence of these sonographic markers and gestational age. Therefore, we assumed that early second-trimester sonography would be at least as accurate as that performed after 16 weeks' gestation. To examine this hypothesis, we looked for the presence of these cranial sonographic markers suggestive of open NTDs in 8011 low-risk cases, using transvaginal sonography (TVS), between the 12th and 17th week of gestation (menstrual age). Fetal NTDs were identified in ten cases (l.25%o). The NTDs were cervico-cranial in three, lumbo-sacral in six, and thoracal in one of the ten cases. None of the seven cases examined was dyskaryotic. Cerebellar dysmorphism, ‘banana’ sign, cerebellar absence, and hypoplasia were detected in all the low NTDs, usually before the detection of the spinal lesion. All the sonographically diagnosed malformations were confirmed by post-abortal examination except in one case, where the patient decided to continue the pregnancy and refused follow-up. We therefore conclude that transvaginal sonographic examination of the fetal skull before the 17th week of gestation is an accurate method for the detection of low NTDs.  相似文献   
809.
铁屑内电解法废水处理装置研究   总被引:10,自引:0,他引:10  
利用铁屑内电解原理研制出了一套动态的废水综合处理装置 ,并利用正交试验法对该装置的主要技术参数进行了探讨。该装置对重金属离子Cr(VI)的去除率可达 10 0 % ,有机物 (苯胺 )的去除率在 80 %以上 ,对实验室实际废水的COD去除率达 90 %以上。  相似文献   
810.
研究离子色谱(IC)与石墨炉原子吸收光谱(GFAAS)联用测定水体中铁形态的方法。用Shim-pack阳离子交换柱分离Fe(Ⅲ)和Fe(Ⅱ),用石墨炉原子吸收法检测,Fe(Ⅱ)和Fe(Ⅲ)的检出限分别为3.8ng/ml和7.7ng/ml。本方法已用于检测自来水和河水的铁的价态,取得了令人满意的结果。  相似文献   
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