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991.
992.
993.
The steady, two-dimensional, incompressible MHD flow past a circular cylinder with an applied magnetic field parallel to
the main flow is studied using the finite difference method. The magnetic Reynolds number is assumed to be small. Results
are presented up to the Reynolds number R=500 and interaction parameter N=1.3. As N increases suppression of the separation is observed. Drag coefficient is decreasing for the small values of N and then increasing as N increases. It is found that a smaller value of far field distance is required as N increases.
Received 6 March 2000 相似文献
994.
995.
Ambient pressure dried TEOS-based silica aerogels: good absorbents of organic liquids 总被引:1,自引:1,他引:0
Jyoti L. Gurav A. Venkateswara Rao D. Y. Nadargi Hyung-Ho Park 《Journal of Materials Science》2010,45(2):503-510
The experimental work has been carried out to study the absorption–desorption properties of the hydrophobic silica aerogel
for the application of oil spill cleanup. Aerogels were synthesized by sol–gel route prior to ambient pressure drying, by
keeping TEOS:MeOH:Acidic H2O:NH4F:NH4OH:HMDZ molar ratio constant at 1:16.5:0.81:0.62:0.63:0.41, respectively. The absorption of organic liquids by as-prepared
aerogels has been carried out by adding the aerogel samples in organic liquid, viz. three alkanes: hexane, heptane, octane;
the aromatic compounds: benzene, toluene, xylene; the alcohols: methanol, ethanol, propanol, and the three oils: petrol, diesel,
and kerosene until it is totally wetted. It was observed that surface-modified TEOS-based aerogel absorbed the organic liquids
and oils by nearly 12 times its own mass. After absorption, desorption time of liquids from the aerogel at various temperatures,
i.e., at 30, 60, 80, and 100 °C was measured. The 50% volume shrinkage of the aerogel in case of oils and 20% in case of organic liquid was observed, after total desorption
of liquids. No significant change in hydrophobicity of the aerogel was observed and it can be reused two times. 相似文献
996.
RB Cain P Fortnagel S Hebenbrock GW Kirby HJ McLenaghan GV Rao S Schmidt 《Canadian Metallurgical Quarterly》1997,238(1):197-201
Vitamin E is one of the most important lipid-soluble antioxidant nutrients. Severe vitamin E deficiency can have a profound effect on the central nervous system. Cystic fibrosis, chronic cholestatic liver disease, abetalipoproteinemia, short bowel syndrome, isolated vitamin E deficiency syndrome and other malabsorption syndromes all may cause varying degrees of neurologic deficits due to related vitamin deficiencies. The classic abnormalities in vitamin E deficiency progress from hyporeflexia, ataxia, limitations in upward gaze and strabismus to long-tract defects, profound muscle weakness and visual field constriction. Patients with severe, prolonged deficiency may develop complete blindness, dementia and cardiac arrhythmias. Treatment must be tailored to the underlying cause of vitamin E deficiency and may include oral or parenteral vitamin supplementation. The more advanced the deficits, the more limited the response to therapy. Therefore, a good neurologic examination and periodic serum vitamin E levels are essential in patients at risk of vitamin E deficiency. 相似文献
997.
The attenuation constant of a circular waveguide completely filled with a homogeneous, isotropic and lossless chiral medium is calculated after first solving the wave equation and determining the field components. The waveguide supports only the hybrid modes and the first modes with azimuthal indices of 0 and 1 are studied.<> 相似文献
998.
Roots of Decalepis hamiltonii are consumed as pickles and as a beverage and are believed to possess health-promoting properties. Roots of D. hamiltonii exhibit antioxidant properties. We have isolated an antioxidant compound from the aqueous extract of the roots of D. hamiltonii and identified it as ellagic acid (EA), based on NMR and MS. EA exhibited free radical-scavenging activity, inhibited LDL oxidation and showed cytoprotective effect against xenobiotic-induced oxidative stress in Ehrlich Ascites tumor cells. EA is a new addition to the list of antioxidant compounds in the roots of D. hamiltonii. 相似文献
999.
岩壁式吊车梁是一种新型结构形式,目前尚无规范可循。关口水电站地下厂房岩壁式吊车梁的设计,采用平面力系平衡的方法来分析梁的稳定,其中壁座倾角、锚杆参数选取是岩壁式吊车梁设计的关键。对中小型水电站来讲,按照施工技术要求:把好施工质量关,是岩壁式吊车梁成败的关键。 相似文献
1000.
We have been exploring the mechanism of action of 5-(3,4-dichlorophenyl) methylhydantoin (hydantoin), an antiviral drug that inhibits the replication of poliovirus in culture. By varying the time of drug addition to infected cells, we found that the drug acts at a stage which is late in the replication cycle and subsequent to the step inhibited by guanidine. Furthermore, we detected normal levels of full-length plus-strand virion RNA in hydantoin-treated cultures. A new assembly intermediate in addition to the expected assembly intermediates was detected in drug-treated cultures. This intermediate has properties consistent with that of a packaging intermediate. Drug-resistant mutants were readily isolated. Sequence analysis of three independent drug-resistant mutants identified amino acid substitutions in the 2C coding region. Reconstruction by site-directed mutagenesis confirmed that these single mutations were sufficient to confer drug resistance. Taken together, these data suggest that the poliovirus 2C region is involved in virus encapsidation and that hydantoin inhibits this stage of replication. 相似文献