Condensation of Diamantan-3-one with Malononitrile and Methyl and Ethyl Cyanoacetates in the Presence of Binder-Free FeHY and NiHy Zeolites

Russian Journal of Organic Chemistry - Binder-free iron- and nickel-containing micro-, meso-, and macroporous zeolites FeHY and NiHY were found to effectively catalyze Knoevenagel condensation of...     

Temperature and frequency dependence of the spin-lattice relaxation times of E′1 centers in neutron-irradiated quartz glass

Results are reported for measurements of the spin-lattice relaxation times of E′₁ centers in quartz glass, produced by neutron irradiation, with the measurements made at two frequencies 9.25 and 24.0 GHz over a wide temperature interval 1.5–300 K. The experimental data are interpreted on the basis of interaction mechanisms of the spins with two-level systems with excitation energies ∼6, ∼26, and ∼420 cm⁻¹. A small modification of the existing theory allows us to explain a number of features of the observed temperature and frequency dependence of the relaxation rate. The results are compared with the data available in the literature on spin-lattice relaxation of irradiation centers in crystalline quartz and quartz glass. Fiz. Tverd. Tela (St. Petersburg) 39, 1335–1337 (August 1997)     

On immersions ofn-dimensional Lobachevskií space in 2n-dimensional Euclidean space withn principal direction fields

In this article we prove that the principal direction fields are holonomic and use them to introduce curvilinear coordinates on an immersed region in terms of which the linear element of Lobachevskií space is written in the form where The fundamental system of equations is established for an immersion ofn-dimensional Lobachevskií space into 2n-dimensional Euclidean space withn principal direction fields for the functions _i and, and a way of constructing an arbitrary local analytic immersion is shown.Translated from Ukrainskií Geometricheskií Sbornik, No. 28, pp. 3–8, 1985.     

The curvatures of asymptotic lines on a domain of three-dimensional Lobachevsky space that is immersed intoE 5

It is assumed that a domain of a three-dimensional Lobachevsky space with curvature equal to – 1 is immersed into E ⁵.It is known that four asymptotic lines pass through every point on the immersed domain. It is proved that the second curvature of the asymptotic line is k ₂ =1/cos, where is the angle formed by vector ₃ from the natural frame of the asymptotic line and the normal plane of the submanifold. The third curvature k ₃ satisfies k ₃ |(d/ds) (1/k ₂ ) |and if k ₃ 0, then the fourth curvature is expressed in terms of k ₂ and k ₃.Thus, any curve in E ⁵ may not be an asymptotic line on a domain of a Lobachevsky space immersed in E ⁵.Translated from Ukrainskii Geometricheskii Sbornik, No. 35, pp. 5–10, 1992.     

The structure of chuin,a new coumarin from the roots of Seseli tschuense

Conclusions 1. The polarographic behavior of galanthamine, lycorine, pancratine, hordenine, and dl-narwedine on a support of 0.01 N (C₂H₅)₄NOH has been studied.2. A chromatopolarographic method for determining the amount of galanthamine in a chloroform extract from plant raw material has been developed.Khimiya Prirodnykh Soedinenii, Vol. 6, No. 4, pp. 450–453, 1970     

Amidation of deltacyclene and hexacyclic norbornadiene dimers with acetonitrile and water catalyzed by FeCl3·6H2O

Abstract

FeCl₃·6H₂O-catalyzed Ritter amidation of deltacyclene and hexacyclic norbornadiene dimers containing both a double bond and a three-carbon ring in the molecule with acetonitrile and water was performed. Depending on the hydrocarbon structure, the reaction proceeds via C-C bond cleavage in the three-carbon ring or at the double bond to form the corresponding N-acetamides.     

Concentration dependence of EPR spectra in mixed (BaF2)1 − x (CeF3) x crystals

Physics of the Solid State - In the EPR spectra of the (BaF2)1 − x (CeF3) x system, additional lines appear as the concentration x in the mixture increases from 10−3 to 10−2, some...     

Asymptotic curves of submanifolds

Translated from Matematicheskie Zametki, Vol. 52, No. 5, pp. 3–12, November, 1992.     

Features of the extraction of essential oils from plant raw material in the presence of surface-active agents

It has been established that the influence of surface-active agents (SAAs), on the extraction of essential oils (EOs) is connected with a fall in the surface tension of water, which facilitates the process of steeping, wetting, and swelling of plant raw material and also the solubilization of the EOs in micellar solutions of SAAs. A. Sultanov Uzbek Scientific Research Institute of Pharmaceutical Chemistry, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 648–652, September–October, 1998.