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961.
Di-region theory, the theory for the mechanism of carcinogenesis, has been extendedsuccessfully on the quantitative Structure-carcinogenic activity relationship (QSCAR) of 63aromatic amines. A quantitative equation for the QSCAR of aromatic amines has been estab-lished by the mechanism conception of the specialized di- functional alkylation between thenitrenium ion of the amino group and the epoxide of the aromatic ring. The agreementbetween calculation and experiment comes up to 98%. Thus, it can now express the puzzlingvariation of the carcinogenicity of aromatic amines, as a comprehensible structure-chemicalreactivity relationship. 相似文献
962.
W. Brandt T. Lehmann T. Hofmann R. L. Schowen A. Barth 《Journal of computer-aided molecular design》1992,6(2):159-174
Summary By theoretical conformational investigations of substrates and nonsubstrates of the enzyme dipeptidyl-peptidase IV (DP IV) as well as dipeptide-esters using the ECEPP83 method we determined the structure of peptides recognized and cleaved by the enzyme. From a comparison of all possible structures for the substrates with conformations not possible in nonsubstrates we concluded that a single conformation explains substrate specificities of DP IV. This conformation is characterized by the following dihedral angles: {ie159-1}, {ie159-2}, {ie159-3}, {ie159-4}, and {ie159-5}. The conclusions were supported by comparisons of molecular electrostatic potentials calculated with the molecular graphics program HAMOG. 相似文献
963.
964.
The nucleation mechanism to predict coercivity values in melt-spun exchange-coupled (Nd1−xPrx)yFe94−yB6 alloys for various Nd:Pr ratios x, and Fe:RE ratios y, was tested using the dependence of the anisotropy constant K1 on Pr content x for the minimum nucleation field HNmin in the modified Brown's equation. Very good agreement was found between experimental data and theoretical values, confirming the predominance of the nucleation of reverse domains over the wall pinning process in the coercivity mechanism of melt spun REFeB alloys. 相似文献
965.
本文用ESR方法考察了Cp2ZrH) Cl与RNCSR=C6H5,c-C6H11,n-C4H9)的反应的过程,结果表明,在这类反应过程中,Zr-H键发生均裂,中心金属锆经过+4-→+3-→+4的价态变化,反应通过自由基机理进行. 相似文献
966.
XIAO LING 《数学年刊B辑(英文版)》1995,(4)
LARGE-TIMEBEHMIOROFSOLUTIONSFORTHESYSTEMOFCOMPRESSIBLEADIABATICFLOWTHROUGHPOROUSMEDIA¥XIAOLING(L.HSIAO)D.SERRE(InstituteofMat... 相似文献
967.
低气压微波感耦氩等离子体空间分布特性光谱诊断 总被引:3,自引:3,他引:0
用二维光学多道分析仪研究了低气压表面波型微波感耦氬等离子体的光谱辐射特性?鼳bel反演后,得到了在各种气压和微波功率下等离子体辐射光强和激发温度的空间分布及其变化规律。讨论了此等离子体的激发机理。 相似文献
968.
L. Ouali S. Stoll E. Pefferkorn A. Elaissari V. Lanet C. Pichot B. Mandrand 《先进技术聚合物》1995,6(7):541-546
The paper describes a study of the kinetics and mechanism of the coagulation of two types of immunoassays using sensitized latexes. The positive response to the first test is based on the aggregation of the gamma globulin (IgG)-coated polystyrene latexes in the presence of IgM rheumatoid antigen. The second test is relative to the heteroaggregation of two types of sensitized latexes induced by the presence of human chorionic gonadotropin (HCG). In the latter test, two identical polystyrene latexes bearing carboxylic acid surface groups were sensitized by covalent coupling of monoclonal antibodies specific for the αHCG determinant on one type of latex and for the βHCG determinant on the other type. Using the Coulter Counter method, the aggregate size distribution c(n) was determined as a function of the number n of elementary constituents, thus enabling calculation of the number N(t) and weight S(t) average sizes of the aggregates. The temporal variations of the average sizes were compared with typical situtions of reaction-limited aggregation processes in order to characterize the mechanism of aggregation induced by antibody–antigen reactions. 相似文献
969.
对于一般情形,给出焦点量和鞍点量计算与约化的Maple算法,从而统一了焦点量和鞍点量的计算,并给出细焦点与细鞍点的变换,利用变换推导了焦点量和鞍点量的关系. 相似文献
970.