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排序方式: 共有265条查询结果,搜索用时 15 毫秒
1.
Polyakov K. M. Mordkovich N. N. Safonova T. N. Antipov A. N. Okorokova N. A. Dorovatovskii P. V. Veiko V. P. 《Crystallography Reports》2021,66(5):786-790
Crystallography Reports - Crystals of mutants of uridine phosphorylase from Shewanella oneidensis MR-1 at the active-site threonine residue were obtained, and the three-dimensional structures of... 相似文献
2.
Mathematical Notes - All the groups considered in this paper are finite, and $$G$$ always denotes a finite group; $$\sigma$$ is a partition of the set $$\mathbb{P}$$ of all primes, i.e.,... 相似文献
3.
4.
I. V. Fedorova E. V. Rumyantsev M. G. Kiselev L. P. Safonova 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2011,85(12):2165-2170
Quantum chemical calculations of the structural characteristics of the bilirubin molecule and its anion are performed. Intramolecular
hydrogen bonds are studied using NBO analysis. It is shown that hydrogen bonds in the bilirubin molecule are nonequivalent,
and the bond formed by the keto oxygen of the pyrrole ring and the hydrogen of the carboxyl group belonging to the propionate
residue is energetically more favorable. Structural characteristics of the molecular and ion forms of bilirubin in aqueous
solution are studied by molecular dynamics simulation. It is found that intermolecular hydrogen bonds with water molecules
are formed due to oxygen atoms of the carboxyl group and the keto group of bilirubin, and the probability of their formation
by anions is much higher than that for molecules. 相似文献
5.
Matthew P. Conley Murielle F. Delley Georges Siddiqi Giuseppe Lapadula Sébastien Norsic Vincent Monteil Olga V. Safonova Christophe Copéret 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2014,126(7):1903-1907
The insertion of an olefin into a preformed metal–carbon bond is a common mechanism for transition‐metal‐catalyzed olefin polymerization. However, in one important industrial catalyst, the Phillips catalyst, a metal–carbon bond is not present in the precatalyst. The Phillips catalyst, CrO3 dispersed on silica, polymerizes ethylene without an activator. Despite 60 years of intensive research, the active sites and the way the first Cr C bond is formed remain unknown. We synthesized well‐defined dinuclear CrII and CrIII sites on silica. Whereas the CrII material was a poor polymerization catalyst, the CrIII material was active. Poisoning studies showed that about 65 % of the CrIII sites were active, a far higher proportion than typically observed for the Phillips catalyst. Examination of the spent catalyst and isotope labeling experiments showed the formation of a Si–(μ‐OH)–CrIII species, consistent with an initiation mechanism involving the heterolytic activation of ethylene at CrIII O bonds. 相似文献
6.
I. V. Fedorova M. G. Kiselev L. P. Safonova 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2011,85(11):1917-1922
Using the AM1 semiempirical method, we calculate the energy profile of the proton transfer reaction during the formation of
a hydrogen bond between molecules of phosphoric acid (H3PO4) and N,N-dimethylformamide (DMFA) in both gas and liquid phases. The energy barriers of the reaction transition are estimated.
The changes in the geometric parameters of hydrogen bonds and the intermolecular interaction energy of H3PO4-DMFA and (H3PO4)2-DMFA complexes during the transition from the gas phase into the solution are analyzed. 相似文献
7.
A. U. Makhkamova É. V. Safonova A. Z. Sadikov E. K. Dobronravova T. T. Shakirov 《Chemistry of Natural Compounds》1989,25(3):380-381
Institute of the Chemistry of Plant Substances, Uzbek SSR Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 436–438, May–June, 1989. 相似文献
8.
O. A. Burova I. D. Bystryakova N. M. Smirnova T. S. Safonova 《Chemistry of Heterocyclic Compounds》1990,26(5):561-564
1,3-Dimethyl-2,4,5-trioxo-7-amino-8H-pyrido[2,3-d]pyrimidine has been brominated, chlorosulfonated, treated with potassium nitrite in acidic medium, and with the Vilsmeier reagent. Acylation and alkylation of 1,3-dimethyl-2,4,5-trioxo-6-bromo-7-aminopyrido[2,3-d]pyrimidine is also discussed.For Communication 1, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 662–666, May, 1990. 相似文献
9.
M. Yu. Rusanova G. A. Tsirlina O. A. Petrii T. Ya. Safonova S. Yu. Vasil’ev 《Russian Journal of Electrochemistry》2000,36(5):457-464
A series of Pd electrodeposits (edPd) on Pt substrates is prepared at deposition potentials of -0.05 to 0.55 V with respect
to a reversible hydrogen electrode in 0.5 M H2SO4. Their nanostructure is characterized by scanning tunneling microscopy. The size distribution of particles is estimated,
and dependences of its maximum and half width on the deposition potential are determined. A comparative coulometric study
of adsorption of copper and oxygen on edPd shows that real surface areas determined from these data substantially differ.
The average size of particles for edPd, estimated within the model of equal-size spheres, is shown to be incorrect. The assumption
that particles in the deposits essentially coalesce is substantiated. It is shown that the equilibrium hydrogen content in
thea and β hydrides is anomalously high for the deposits whose growth was accompanied by deep hydrogenation of Pd. At a given
effective pressure, for the α-phase, this value is always substantially higher as compared with less defective materials.
In the β-phase, the hydrogen concentration can be either lower or higher 相似文献
10.
Siberian Mathematical Journal - We study some conditions for a group to be $ \sigma $ -solvable or meta- $ \sigma $ -nilpotent. 相似文献