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1.
N. M. Tutynina N. L. Racheva V. A. Maslivets Z. G. Aliev A. N. Maslivets 《Russian Journal of Organic Chemistry》2013,49(1):95-98
3-Aroyl-1H-pyrrolo[2,1-c][1,4]benzoxazine-1,2,4-triones reacted with 5,5-dimethylcyclohexane-1,3-dione to give 3′-aroyl-4′-hydroxy-1′-(2-hydroxyphenyl)-6,6-dimethyl-6,7-dihydrospiro[1-benzofuran-3,2′-pyrrole]-2,4,5′(1′H,5H)-triones. The crystalline and molecular structures of 3′-benzoyl-4′-hydroxy-1′-(2-hydroxyphenyl)-6,6-dimethyl-6,7-dihydrospiro[1-benzofuran-3,2′-pyrrole]-2,4,5′(1′H,5H)-trione were determined by X-ray analysis. 相似文献
2.
V. Divarova K. Stojnova P. Racheva V. Lekova 《Russian Journal of Inorganic Chemistry》2018,63(7):974-977
The possibility of application of the ion-associated complex formed between the anionic chelate cobalt(II)-4-(2-thiazolylazo) resorcinol (TAR) with the cation of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) for extraction-spectrophotometric determination of cobalt in the form of an ion associate in Vitamin B12 was studied. The liquid–liquid extraction system Co(II)-TAR-MTT-H2O-CHCl3 was applied. This system was chosen by our previous research of the ion associates of the cobalt by spectrophotometric investigation of fourteen different liquid–liquid extraction systems, containing azo derivatives of resorcinol (TAR or 4-(2-pyridylazo) resorcinol (PAR)) and mono or ditetrazolium salts. Based on the obtained results, a sensitive, relatively simple, convenient and inexpensive method for determination of cobalt in the form of an ion associate in Vitamin B12 was developed. The proposed method can be implemented for biological, medical and pharmaceutical samples containing cobalamin (Vitamin B12). 相似文献
3.
K. Stojnova P. Racheva V. Divarova K. Bozhinova V. Lekova 《Russian Journal of Inorganic Chemistry》2017,62(2):249-256
The formation of an ion-associated complex between the anionic chelate of Mo(VI)–3,5-dinitrocatehol (3,5-DNC) and the cation of 3-(2-naphthyl)-2,5-diphenyl-2H-tetrazolium chloride (TV) in the liquid–liquid extraction system Mo(VI)–3,5-DNC–TV–H2O–CHCl3 was studied by spectrophotometry. The optimum conditions for the complex formation and extraction of the ion-associated complex were established. The effect of co-existing ions and reagents on the process of complex formation was investigated under optimum extraction conditions. The validity of Beer’s law was checked and some analytical characteristics were calculated. The association process in aqueous phase and the extraction equilibria were investigated and quantitatively characterized. The following key constants of the processes were calculated: association constant, distribution constant, extraction constant and recovery factor. The molar ratio of the reagents was determined by independent methods. Based on this, a reaction scheme, a general formula and a structure of the complex were suggested. 相似文献
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5.
Stoyan V. Stoyanov Borjana Racheva-Iotova Svetlozar T. Rachev Frank J. Fabozzi 《Annals of Operations Research》2010,176(1):293-309
Portfolio risk estimation in volatile markets requires employing fat-tailed models for financial returns combined with copula
functions to capture asymmetries in dependence and an appropriate downside risk measure. In this survey, we discuss how these
three essential components can be combined together in a Monte Carlo based framework for risk estimation and risk capital
allocation with the average value-at-risk measure (AVaR). AVaR is the average loss provided that the loss is larger than a
predefined value-at-risk level. We consider in some detail the AVaR calculation and estimation and investigate the stochastic
stability. 相似文献
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7.
Borjana V. Donkova Katja I. Milenova Dimitar R. Mehandjiev 《Central European Journal of Chemistry》2008,6(1):115-124
The precursors with a low manganese content ≤ 0.07% Mn were synthesized by spontaneous crystallization from Zn2+, Mn2+ and C2O4
2−-containing solutions. The initial ratio Zn2+:C2O4
2− = 1:1 and 1:2 influences the morphology and prevailing orientations of the crystallites in the oxalate samples. The presence
of such small Mn content in the samples does not change the morphology or size of the crystals. The ZnO and Mn/ZnO oxides
with manganese content from 0.51×10−2 to 15.1×10−2 Wt % are obtained after thermal decomposition of the oxalates. The oxides preserved the morphology of the precursors. The
catalytic tests show that the pure ZnO has a poor activity for CO oxidation reaction. Its doping with Mn promotes the catalytic
activity (up from twice to five times) in spite of the very low contents of the dopants. The observed increase of the activity
depends on both dopant concentration and Zn2+:C2O4
2− ratio, probably due to the different mechanism of the manganese inclusion and different morphology of the oxides. The catalysts
of the 1:2 series are more active in CO oxidation reaction.
相似文献
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9.
N. L. Racheva Z. G. Aliev A. N. Maslivets 《Russian Journal of Organic Chemistry》2008,44(8):1184-1188
3-Aroyl-1H-pyrrolo[2,1-c][1,4]benzoxazine-1,2,4-triones react with methyl 4-aryl-2-arylamino-4-oxobut-2-enoate to give substituted methyl 7-aryl-4,9-bis(aroyl)-3-hydroxy-1-(2-hydroxyphenyl)-2,6-dioxo-1,7-diazaspiro[4.4]nona-3,8-diene-8-carboxylates
which undergo thermal cyclization to methyl 9-aroyl-4,7-diaryl-1-(2-hydroxyphenyl)-2,3,8-trioxo-2,3,7,8-tetrahydro-1H,6H-6,8a-methanopyrrolo[2,3-e][1,3]oxazepine-6-carboxylates. The crystalline and molecular structures of methyl 9-benzoyl-1-(2-hydroxyphenyl)-2,3,8-trioxo-4,7-diphenyl-2,3,7,8-tetrahydro-1H,6H-6,8a-methanopyrrolo[2,3-e][1,3]oxazepine-6-carboxylate was studied by X-ray analysis.
Original Russian Text ? N.L. Racheva, Z.G. Aliev, A.N. Maslivets, 2008, published in Zhurnal Organicheskoi Khimii, 2008, Vol.
44, No. 8, pp. 1197–1201.
For communication LX, see [1]. 相似文献
10.
The main purpose of this article is to present a new numerical procedure that can be used to implement a variety of different
interest rate models. The new approach allows to construct no-arbitrage models for the term structure, where the stochastic
process driving the rates is infinitely divisible, as in the cases of pure-diffusion and jump-diffusion mean reverting models.
The new method determines a unique fully specified hexanomial tree, consistent with risk neutral probabilities. A simple forward
recursive procedure solves for the entire tree. The proposed lattice model, which generalized the Hull and White [37] single-factor
model, is relatively simple, computational efficient and can fit any initial term structure observed in the market. Numerical
experiments demonstrate how the jump-diffusion mean reverting model is particularly suited to describe the European money
market rates behavior. Interest rates controlled by the monetary authorities behave as if they are jump processes and the
term structure, at short maturity, is contingent upon the levels of these official rates. 相似文献