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排序方式: 共有78条查询结果,搜索用时 15 毫秒
1.
Ostanina T. N. Rudoi V. M. Yaroslavtseva O. V. Solov'ev A. S. Subbotina O. Yu. Dokashenko S. I. 《Russian Journal of Electrochemistry》2004,40(10):1019-1023
The impedance of zinc-rich polymer coatings on steel in a 3-% NaCl solution is studied. The electrochemical behavior of the electrode is satisfactorily described by an equivalent circuit that contains a constant-phase element, which reflects fractal properties of the zinc surface in the binder. From the results of calculations of the circuit elements for metal-rich electrodes with different zinc contents computed are fractions of the active area of the surface of the coating and its fractal dimensionality. 相似文献
2.
V. A. Bakulev Yu. O. Subbotina V. M. F. Fabian 《Chemistry of Heterocyclic Compounds》2003,39(11):1504-1515
The cyclization of 1,3,5-hexatrien-1-one, 1, and the Z- and E-isomers of 1-aza-1,3-butadienylketene 3 were studied using the semiempirical AM1 and PM3 methods. Cyclizations of compounds 1 and Z-3 are shown to occur via a mono-rotation mechanism with barriers of 15.49 and 32.85 kcal/mol respectively. The reactions proceed via non-planar transition states which result from rotation of the methylene group for compound 1 and the imino group for compound Z-3. Cyclization of E-3 proceeds via a non-rotatory mechanism through a planar transition state. The activation barrier is 4.83 kcal/mol (AM1). The electronic structures of the initial and final states, and of some intermediate structures, including the transition states for the cyclization of compounds 1 and 3, were analyzed by the natural orbital method using HF/6-31G*//AM1 calculations. Energetic, structural, and orbital criteria indicate the heteroelectric mechanism for the cyclization of compound E-3 and the pericyclic mechanism for the cyclization of compounds 1 and Z-3. 相似文献
3.
IR Spectroscopic Study of Ethylene Adsorption and Oligomerization on the Hydrogen Form of Mordenite 总被引:2,自引:0,他引:2
Diffuse-reflectance IR spectroscopy is used to study adsorption and oligomerization of ethylene on the hydrogen form of mordenite at room temperature. Ethylene adsorbs on bridging acid hydroxyl groups of the zeolite and forms -complexes with a firm hydrogen bond. The interaction with hydroxyl groups most strongly excites composite vibrations in adsorbed molecules. These vibrations are a combination of the stretching vibration of a double bond and the deformational vibrations of the CH2 group. A conjecture is drawn that these composite vibrations correspond to the reaction coordinate of ethylene transformation to the ethoxy groups. Their further reactions with weakly adsorbed molecules result in ethylene oligomerization. A linear oligomer is formed, grafted on the zeolite surface and filling the pores of zeolites. 相似文献
4.
Armaan GÜNSEL Aye USLUOLU Ahmet Turgut BLGL TOSUN Büra Gülnur ARABACI Meryem Nilüfer YARAIR 《Turkish Journal of Chemistry》2020,44(4):923
This work reports on dyeing of nylon/elastane fabric with water-soluble phthalocyanines ( 1-4 ) bearing quinoline 5-sulfonic acid substituents on the peripheral or nonperipheral positions and determining the antibacterial efficiency of the phthalocyanine compounds and the dyed nylon/elastane fabrics. The light, washing, water, perspiration, and rubbing fastness properties of nylon/elastane fabrics dyed with phthalocyanines were also determined. The results showed that all dyed fabrics showed very good wet fastness values. The lightfastness value of the nylon/elastane fabric dyed with phthalocyanine dye ( 1 ) showed a much better value than the others. Also, the antibacterial efficiencies of the dyed nylon fabrics and the dye compounds were investigated against a gram-negative ( Escherichia coli ) and a grampositive ( Staphylococcus aureus ) bacteria by using disc diffusion method. The results showed that the dyed nylon/elastane fabrics and the compounds exhibited antibacterial activities against both bacteria. 相似文献
5.
A. V. Bulatov P. A. Ivasenko K. A. Subbotina A. B. Vishnikin L. N. Moskvin 《Journal of Analytical Chemistry》2010,65(3):234-238
A procedure for the automatic photometric determination of phosphate ions in natural waters was developed, based on the formation
of a colored ion associate of the reduced form of phosphomolybdic heteropoly anion with a polymethine dye, Astra Phloxine.
The detection limit was 5 μg P/L at the sample volume of 0.3 mL. 相似文献
6.
N. N. Subbotina T. B. Tokmantsev 《Proceedings of the Steklov Institute of Mathematics》2015,288(1):173-179
A novel dual approach to the problem of optimal correction of first-kind improper linear programming problems with respect to their right-hand sides is proposed. It is based on the extension of the traditional Lagrangian by introducing additional regularization and barrier components. Convergence theorems are given for methods based on the augmented Lagrangian, an informal interpretation of the obtained generalized solution is suggested, and results of numerical experiments are presented. 相似文献
7.
The Dirichlet problems for singularly perturbed Hamilton–Jacobi–Bellman equations are considered. Some impulse variables in the Hamiltonians have coefficients with a small parameter of singularity ε in denominators.The research appeals to the theory of minimax solutions to HJEs. Namely, for any ε>0, it is known that the unique lower semi-continuous minimax solution to the Dirichlet problem for HJBE coincides with the value function uε of a time-optimal control problem for a system with fast and slow motions.Effective sufficient conditions based on the fact are suggested for functions uε to converge, as ε tends to zero. The key condition is existence of a Lyapunov type function providing a convergence of singularly perturbed characteristics of HJBEs to the origin. Moreover, the convergence implies equivalence of the limit function u0 and the value function of an unperturbed time-optimal control problem in the reduced subspace of slow variables. 相似文献
8.
9.
V. M. Kamyshov P. V. Gel'd A. G. Gorbatov A. N. Men' Yu. A. Nechaev T. S. Subbotina 《Russian Physics Journal》1972,15(6):831-835
In a cluster model of defective solid solutions the cluster components are determined and their concentration is found as a function of the defectiveness for solutions \(Me_{c_1 }^{(1)} Me_{c_2 }^{(2)} B_x^{(1)} B_y^{(2)}\) in the case of limited and unlimited solubility. An interpretation is given of the dependence of the lattice parameter, magnetic moment, and Curie point on the composition in a cluster component model, using the example of oxycarbides, oxynitrides, and solutions of certain metals in Mn4N. 相似文献
10.
N. N. Subbotina L. G. Shagalova 《Proceedings of the Steklov Institute of Mathematics》2016,293(1):183-198
The Cauchy problem for the Hamilton–Jacobi equation with state constraints is considered. A justification for a construction of a generalized solution with given structure is provided. The construction is based on the method of characteristics and on solutions of problems related to calculus of variations. 相似文献