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831.
Long-wall mining method has its own advantages, such as small mining-cutting ratio, the simple technique of recovery and high level of mechanization, which is the optimal method used to mine gently inclined and extremely thin iron mine. How to ensure the safety of workers and equipment during mining is the key technical process. Based on elastic-plastic mechanics theory, the mechanic model of long-wall method mining gently inclined and extremely thin iron mine is established and the critical safety distance of workface is obtained. With the FLAC-2D simulation software, the rule of stress change, the deformation of workface and surrounding rock in different control-roof width are also summarized. The final results accord with the ones of theory test. We confirm the support-frame resistance of workface by analogy-statistic method. The results prove that hydraulic support-frame have the ability to provide enough pressure to assure the stability of working face within the 5-m of control-roof width. 相似文献
832.
W. O. Wan Nadirah M. Jawaid Abeer A. Al Masri H. P. S. Abdul Khalil S. S. Suhaily A. R. Mohamed 《Journal of Polymers and the Environment》2012,20(2):404-411
A study on chemical, morphology, and thermal analysis of cultivated pineapple leaf fibres (PALF) were carried out. The chemical compositions were determined by using Technical Association Pulp and Paper Industries standards. Fourier Transform-Infrared Spectroscopy analysis of PALF detect sharp band at 1,733?cm?1, due to the absorption of carbonyl stretching of ester and carboxyl groups which is most abundant in pineapple leaf hemicelluloses. Cell wall ultra structure of PALF was studied by using Transmission electron microscopy. Transmission electron micrograph confirmed that cell wall structure of PALF consists of middle lamella, primary wall and secondary wall including S1, S2 and S3 layers. X-Ray Diffraction indicated that PALF have crystalline nature. Thermal analysis of PALF shows that T10% and T50% weight loss occurred at temperature of 212 and 306?°C respectively. Differential Scanning Calorimetry of PALF showed the broad endothermic peak at a temperature of 80?°C. The relationships between these properties were discussed and relate it with industrial application of pineapple leaf fibers. 相似文献
833.
Yi KW Lee MY 《Journal of environmental biology / Academy of Environmental Biology, India》2003,24(1):17-22
Effects of various environmental stresses such as heavy metals, salts and low (high) temperature on the secretion of peroxidase isozyme into the medium were examined in rice (Oryza sativa cv. Nak-Dong) suspension culture. The major extracellular peroxidases secreted into the medium by various stresses were cationic isoperoxidases. A far migrating cationic isoperoxidase RC3 was isolated from the medium after application of CaCl2, the effective stimulator for peroxidase secretion. Isolation of extracellular isoperoxidase RC3 was accomplished by ammonium sulfate fractionation, CM-cellulose cation-exchange chromatography, and Sephacryl S-100 gel filtration. The enzyme was a glycoprotein having molecular weight of approximately 34 KDa as determined by SDS-PAGE and 38 KDa by Sephacryl S-100 gel filtration. The pI value of the enzyme was 8.9. Kinetic studies revealed that the optimum pH of the enzyme was 6.0 for guaiacol and H2O2, and the Km values for guaiacol and H2O2 were 10.5 mM and 3.2 mM, respectively. 相似文献
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Application of sewage sludge and intermittent aeration strategy to the bioremediation of DDT-and HCH-contaminated soil 总被引:1,自引:0,他引:1
Adding organic amendments to stimulate the biodegradation of pesticides is a subject of ongoing interest. The effect of sewage sludge on the bioremediation of dichlorodiphenyltrichloroethane(DDT) and hexachlorocyclohexane(HCH) contaminated soil was investigated in bench scale experiments,and intermittent aeration strategy was also used in this study to form an anaerobic–aerobic cycle. Bioremediation of DDT and HCH was enhanced with the addition of sewage sludge and the intermittent aeration. The removal rates of HCH and DDT were raised by 16.8%–80.8% in 10 days. Sewage sludge increased the organic carbon content from 6.2 to218 g/kg,and it could also introduce efficient degradation microbes to soil,including Pseudomonas sp.,Bacillus sp. and Sphingomonas sp. The unaerated phase enhanced the anaerobic dechlorination of DDT and HCH,and anaerobic removal rates of β-HCH,o,p′-DDT and p,p′-DDT accounted for more than 50% of the total removal rates,but the content of α-HCH declined more in the aerobic phase. 相似文献
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在介绍中国环境保护标准体系发展概况的基础上,对国家污染物排放(控制)标准的体系结构、内容设置进行了研究,探讨了新时期国家污染物排放(控制)标准的发展趋势,结合实例分析了水污染物特别排放限值、有毒污染物的监控等在新颁布的排放(控制)标准中的适用要求。 相似文献