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61.
A method for the rapid and quantitative determination of aflatoxin B1 from small quantities of liver, around 1-2 g, is described. The extraction procedure involves acidification to pH 2 of the aqueous liver homogenates, extraction with chloroform: acetone and HPLC-fluorimetric detection after derivatization with trifluoroacetic acid. Quantitative recovery of aflatoxin B1 from chick liver was achieved and detection at levels of 0.2-1 ppb was proved feasible. The aflatoxin B1 concentration in chick liver after oral administration is also shown. 相似文献
62.
X. S. Ning K. Suganuma T. Okamoto A. Koreeda Y. Miyamoto 《Journal of Materials Science》1989,24(8):2879-2883
Two kinds of additive-free silicon nitride ceramics were brazed with aluminium; one was with as-ground faying surfaces and
the other was with faying surfaces heat-treated at 1073K for 1.8 ksec in air. The heat-treatment of the silicon nitride ceramics
formed a silicon oxynitride layer on the faying surfaces and increased the brazing strength of the joints. A silica-alumina
non-crystalline layer and a β′-sialon layer were formed successively from the aluminium side at the interface of the joints.
The heat-treatment which made the former layer thicker is a necessary process in making reliable, strong brazed joints. 相似文献
63.
Kitakami O. Ogawa Y. Fujiwara H. Kugiya F. Suzuki M. 《IEEE transactions on magnetics》1989,25(3):2607-2611
A Co-Cr film deposited directly on a substrate has an initial growth layer with low coercivity. However, the existence of a Ti underlayer prevents the formation of such a layer. As a result, Co-Cr film deposited on a Ti underlayer has high perpendicular anisotropy and coercivity even in cases of extremely thin film thickness (200 Å). As for the read-write characteristics of Co-Cr thin-film media, the existence of such an initial growth layer greatly improves the reproduced output level. The cause for this is considered to be that the free charges which appear on the back surface of the perpendicular recording layer are reduced and the demagnetization field acting on the recorded magnetization subsequently decreases due to the existence of the initial growth layer 相似文献
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Y. Nath P. C. Dumir R. S. Bhatiaf 《International journal for numerical methods in engineering》1985,21(3):565-578
The present work investigates the efficacy and applicability of interior global orthogonal point collocation method to the axisymmetric nonlinear analysis of elastic circular plates and shallow spherical shells subjected to uniformly distributed transverse load. Spacewise discretisation has been carried out using a polynomial expansion with the zeros of a Chebyshev polynomial as collocation points. Timewise integration has been carried out with Newmark k-β scheme corresponding to average acceleration method. The static response and snap-through buckling results, as well as, the dynamic response and dynamic buckling results under a uniformly distributed step load have been obtained and found to agree closely with the available results. 相似文献
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