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41.
Potential of thermal analysis as applied to studying the kinetics of thermal degradation of polymers
A. A. Koptelov I. A. Koptelov A. A. Rogozina E. S. Yushkov 《Russian Journal of Applied Chemistry》2016,89(9):1454-1460
The kinetics of thermal degradation of low-density polyethylene was studied by TGA and DSC at heating rates from 0.5 to 40 deg min–1. Causes of significant discrepancies in the published effective kinetic constants of the overall reaction of thermal degradation of the polymers, determined using different experimental methods and different data treatment procedures, were analyzed. The possibility of using random break model as an alternative approach to describing polymer thermal degradation curves obtained by thermal analysis methods was demonstrated by the example of polyethylene. 相似文献
42.
A. A. Alekseev A. A. Bergman A. I. Berlev E. A. Koptelov B. F. Samylin M. I. Svirin A. M. Trufanov B. I. Fursov V. S. Shorin 《Physics of Atomic Nuclei》2010,73(9):1487-1498
The cross section for 244Cm fission induced by neutrons of energy in the range between 0.07 eV and 20 keV was measured by using the lead slowing-down
spectrometer (LSDS-100) of the Institute for Nuclear Research (Russian Academy of Sciences, Moscow). The parameters of the
resonance areas were determined for the lowest eight s-wave neutron resonances, and the respective fission widths were evaluated. Also, the parameters of the intermediate structure
in the cross section for the subbarrier fission of 244Cm nuclei were evaluated. The results were compared with available data and recommendations based on evaluations. 相似文献
43.
Aroylation of 5,6,8,8a,13,14,16,16a-octahydro[1,2,4,5]tetrazino[6,1-a:3,4-a′]diisoquinoline or 1,3,4,8b-tetrahydro[1,2]diazireno[3,1-a]isoquinoline, as well as reactions of 2-(2-bromoethyl)benzaldehyde with aroylhydrazines followed by treatment with triethylamine,
led to the formation of stable azomethine imines, aroyl(3,4-dihydroisoquinolinium-2-yl)azanides. 1,3-Dipolar cycloaddition
of the latter to N-mesitylmaleimide was stereoselective: the ratio of the trans- and cis-adducts was ∼(3–7): 1, the former prevailing. The reactions with N-arylmaleimides having no ortho-substituents in the aryl group gave the corresponding cis-adducts as the major products [trans/cis ratio ∼1: (2.5–10)]. 相似文献
44.
Yu. B. Koptelov S. P. Saik A. P. Molchanov S. I. Selivanov 《Russian Journal of Organic Chemistry》2011,47(3):421-432
Thermally induced opening of the diaziridine ring at the carbon-nitrogen bond in unsymmetrically substituted 6-aryl-1,5-diazabicyclo[3.1.0]hexanes is characterized by low regioselectivity which is likely to be determined by the inductive effect of substituents in the trimethylene bridge. 1,3-Dipolar cycloaddition of the resulting azomethine imines to phenyl isocyanate is regioselective: it occurs at the double carbon-nitrogen bond with predominant formation of the corresponding cis adducts due to dipolarophile approach to Z-azomethine imine at the sterically less hindered side. Analogous approach of dipolarophile is also observed in the reaction with N-arylmaleimides. 相似文献
45.
The thermal opening of the diaziridine ring in 1-methyl-and 1,3,3-trimethyl-1,3,4,8b-tetra-hydro[1,2]diazirino[3,1-a]isoquinolines
in the presence of N-arylmaleimides leads to the predominant or exclusive formation of the trans isomers of the products of
1,3-dipolar cycloaddition. In the absence of dipolarophile, the conversion of the starting diaziridines is incomplete over
the same time period, while the thermolysis products are N-[3,4-dihydro-2(1H)-isoquinolyl]-and N-[3,3-dimethyl-3,4-di-hydro-2(1H)-isoquinolyl]-N-methyleneamines
formed as the result of isomerization of intermediate labile azomethineimines.
Dedicated to the memory of A. A. Potekhin.
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Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 1071–1079, July, 2008. 相似文献
46.