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1.
The photoconductivity and electrical conductivity, the thermally stimulated polarization and depolarization currents, the
permittivity, and the dielectric losses of noncentrosymmetric Ca3Ga2Ge4O14 crystals of a structural type of trigonal calcium gallogermanate (CGG) have been studied for the first time in the temperature
interval 100–700 K in air and in vacuum. The features of the temperature behavior of CGG are associated, in particular, with
the effect of electrically active defects and partial disordering of the cation sublattice of the crystal structure, which
generates polar formations (dipoles) of several kinds. Certain parameters of the electromigration and of the electrically
active defects that cause charge-relaxation and polarization effects are determined. It is concluded that dipole relaxation
in CGG makes it a new representative of a class of materials in which reorientation of the dipoles as a system of mobile local
distortions of the structure has a substantial effect on the physical properties.
Fiz. Tverd. Tela (St. Petersburg) 39, 871–876 (May 1997) 相似文献
2.
F. A. Mikhailenko L. I. Shevchuk V. S. Tolmacheva F. S. Babichev 《Chemistry of Heterocyclic Compounds》1982,18(7):723-727
2,3,3-Trimethyl-3H-pyrrolo[3,2-c]quinoline and its 8-methoxy derivative were obtained from methyl isopropyl ketone 4-quinolylhydrazones. These bases form quaternary salts at the azine nitrogen atom, from which polymethine dyes were obtained. The changes in the absorption spectra of the dyes in solutions with various acidities were examined.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 948–951, July, 1982. 相似文献
3.
G. V. Shevchuk Yu. S. Vollerner A. S. Shashkov M. B. Gorovits V. Ya. Chirva 《Chemistry of Natural Compounds》1991,27(6):706-711
Two new glycosides which have been called nolinofurosides G(I) and H(III), have been isolated from the leaves ofNolina microcarpa. Nolinofuroside G is the sodium salt of 26-β-D-glucofuranosyloxy-(25S)-furost-5,20(22)-diene-1β, 3β-diol 1-sulfate, and nolinofuroside
H is the sodium salt of 1-β-D-fucopyranosyloxy-26-β-D-glucopyranosyloxy-(25S)-furost-5,20(22)-dinen-1β-3β-ol 3-sulfate.
M. V. Frunze Simferopol' State University. Institute of the Chemistry of Plant Substances, Uzbek. Academy of Sciences, Tashkent.
Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 801–806, November–December, 1991. 相似文献
4.
Bruckbauer A Ying L Rothery AM Zhou D Shevchuk AI Abell C Korchev YE Klenerman D 《Journal of the American Chemical Society》2002,124(30):8810-8811
We present a new, general method for the controlled deposition of biological molecules on surfaces, based on a nanopipet operating in ionic solution. The potential applied to the pipet tip controls the flux of biological molecules from the pipet, allowing fine control of the delivery rate. We used the ion current to control the distance of the pipet from the surface of a glass slide and deposited the fluorescently labeled DNA or protein G at a defined location onto the surface. Features of 830 nm size were obtained by depositing the biotinylated DNA onto a streptavidin surface; 1.3 mum size spots were obtained by depositing protein G onto a positively charged glass surface. 相似文献
5.
A coagulation of nanodispersed TiO2 hydrosol mainly consisting of individual anatase nanocrystallites stabilized with HCl was studied. It was shown that only a part of a dispersed phase coagulates when a certain amount of HCl was added to the sol, and larger nanocrystallites are settled first. The procedure for the separation of the sol into the fractions of various dispersity was developed. 相似文献
6.
Condensation of isatin--anil with acetylacetone and with derivatives of malonic and acetoacetic acids in acetic anhydride has given 5 indogenides. It is observed that isatin--anil is readily acetylated by acetic anhydride. The acetyl derivative is very reactive, and is an intermediate in the condensation of isatin--anil with acetylacetone in acetic anhydride. The indogenides which have been synthesized are nonphototropic as a result of the presence of intramolecular hydrogen bonds.For part IX, see [1]. 相似文献
7.
N. P. Krut'ko L. V. Dikhtievskaya A. D. Markin V. V. Shevchuk A. S. Gorbachev M. M. Varava V. M. Kirienko 《Russian Journal of Applied Chemistry》2005,78(8):1213-1217
The surface activity of higher aliphatic amines and their salts at the interface between their solutions and air, oil, and KCl grains and their influence on the strength characteristics, moisture absorption, and caking of the grains were studied. 相似文献
8.
9.
O. G. Kulinkovich T. A. Shevchuk V. E. Isakov K. N. Prokhorevich 《Russian Journal of Organic Chemistry》2006,42(5):659-664
Homoallyl and bishomoallyl alcohols with a disubstituted double bond treated with ethylmagnesium bromide in the presence of titanium(IV) isopropoxide are converted into the products of a reductive ethylation of the olefin fragment. Under similar conditions esters of β,γ-unsaturated carboxylic acids undergo a successive cyclopropanation of the ester group and reductive ethylation of the double carbon-carbon bond and yield 1-(3-ethylalkyl)cyclopropanols. The features of the observed reactions are explained in the framework of the carbometallation mechanism of the double carbon-carbon bond by the action of dialkoxytitanacyclopropane reagents. 相似文献
10.