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1.
Modified procedures were developed for the detection of -hydroxybutyric acid and 1,4-butanediol (its metabolic precursor) in foods, food additives, and urine using gas chromatography and gas chromatography–mass spectrometry. The analytical range was 0.1–20 wt %. 相似文献
2.
E. Yu. Mikhteeva E. G. Savchuk E. A. Tararako E. B. Merkulov V. K. Goncharuk 《Journal of Structural Chemistry》2005,46(6):1082-1085
Images of cleaved surfaces were obtained for 53ZrF4-20BaF2-4LaF3-3AlF3-20NaF (ZBLAN) glasses and fused quartz using an NTMDT atomic force microscope. It is shown that the scatter of particle size depends on the cooling rate and is 21–48.5 Å for the cleaved surface of ZBLAN glass obtained by very fast cooling and 68–172 Å for the cleaved surface of ZBLAN after slow cooling. For cleaved fused quartz, the range is 25-18 Å. 相似文献
3.
N. M. Kompanichenko A. A. Omel’chuk R. N. Savchuk I. N. Skriptun 《Russian Journal of Inorganic Chemistry》2006,51(7):996-999
We report on the reaction of chromium trifluoride with zirconium in NaF:ZrF4 = 50:50 (mol/mol) mixed melts. Chemical analysis, X-ray powder diffraction, differential thermal analysis (DTA), and IR spectroscopy show that at 400–600°C zirconium reduces chromium(III) fluoride to Cr2+ or Cr0 compounds and reduces zirconium tetrafluoride to ZrF2–x , where 0 < x < 0.2; the particular products depend on the zirconium concentration in the batch. 相似文献
4.
Krinochkin A. P. Shabunina O. V. Savchuk M. I. Kudryashova E. A. Rybakova S. S. Ladin E. D. Kopchuk D. S. Zyryanov G. V. Chupakhin O. N. 《Russian Journal of Organic Chemistry》2022,58(6):917-919
Russian Journal of Organic Chemistry - An efficient synthetic approach to 3-(4-carboxyphenyl)pyridine-2,6-dicarboxylic acid has been developed on the basis of “1,2,4-triazine”... 相似文献
5.
Slepukhin P. A. Krinochkin A. P. Starnovskaya E. S. Shtaitz Ya. K. Savchuk M. I. Kopchuk D. S. Egorov I. N. Santra S. Zyryanov G. V. Chupakhin O. N. 《Russian Chemical Bulletin》2022,71(7):1533-1543
The structures of six 2,2′-bipyridine derivatives containing aromatic amine moieties, namely N-aryl-4-aryl-1-(pyridin-2-yl)-6,7-dihydro-5H-cyclopenta[c]pyridine-3-amines, were studied by single-crystal X-ray diffraction. The molecular structures and the effect of the substituents of these compounds on the crystal packing are discussed.
相似文献6.
This paper deals with Sturm-Liouville operators generated on a finite interval and on the whole axis by the differential expressionl(y)=−y
"
+q(x)y, whereq(x) is a distribution of first order, such that
. The minimal and maximal operators corresponding to potentials of this type on a finite interval are constructed. All self-adjoint
extensions of the minimal operator are described and the asymptotics of the eigenvalues of these extensions is found. It is
proved that the constructed operator coincides with the norm resolvent limit of the Sturm-Liouville operators generated by
smooth potentialsq
n
, provided that the condition
holds. The convergence of the spectra of these operators to the spectrum of the limit operator is also proved. Similar results
are obtained in the case of the whole axis.
Translated fromMatematicheskie Zametki, Vol. 66, No. 6, pp. 897–912, December, 1999. 相似文献
7.
8.
V. V. Savchuk 《Ukrainian Mathematical Journal》2004,56(7):1127-1143
We obtain exact values for the best approximation of a reproducing kernel of a system of p-Faber polynomials by functions of the Hardy space Hq, p-1 + q-1 = 1 and a Szegö reproducing kernel of the space E2(Ω) in a simply connected domain Ωwith rectifiable boundary. 相似文献
9.
We have investigated the IR reflection spectra of ferroelectric ceramics based on solid solutions of lead zirconate-titanate with a rhombohedral structure obtained by high-pressure cold precompaction. In the 55–65-cm–1 frequency range, we have revealed by experiment that the soft ferroelectric-active mode for the ceramics compacted by a higher pressure under the conditions of cold compaction is shifted into the region of lower frequencies. For the ceramics precompacted at various pressures, we have determined the frequencies of longitudinal and transverse phonons and calculated the frequency dependences of the imaginary and real parts of the dielectric constant. 相似文献
10.
A. F. Kireev I. V. Rybal’chenko V. I. Savchuk V. N. Suvorkin V. I. Kholstov 《Journal of Analytical Chemistry》2000,55(9):837-845
An approach is considered to the problem of identification of alkylphosphonic acid derivatives within Chemical Weapons Convention.
The technique is based on correlations between the structural fragments of toxic chemicals and their IR and mass spectra. 相似文献