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排序方式: 共有226条查询结果,搜索用时 140 毫秒
51.
Tkachuk Viktor M. Melnykov Serhii V. Vorobei Anastasiia V. Sukach Volodymyr A. Vovk Mykhailo V. 《Chemistry of Heterocyclic Compounds》2019,55(1):66-71
Chemistry of Heterocyclic Compounds - Cyanoacetic acid reacted selectively with 4-(trifluoromethyl)pyrimidin-2(1Н)-ones with the formation of Michael addition–decarboxylation products... 相似文献
52.
M. E. Kaliekperov A. L. Kozlovskii M. V. Zdorovets D. I. Shlimas 《High Energy Chemistry》2018,52(5):419-422
The effect of irradiation of copper films with low-energy He2+ ions on their structural properties has been studied. The surface morphology and structural properties of the samples before and after irradiation have been examined by scanning electron microscopy, energy dispersive analysis, and X-ray diffraction. Bombardment of the initial samples with He2+ ions at a fluence of 1 × 1016ion/cm2 alters the surface morphology of copper films and leads to the formation of nanoscale inclusions of hexagonal shape. An increase in the fluence to 1 × 1017 ion/cm2 and higher results in the formation of cracks and amorphous oxide inclusions on the sample surface. 相似文献
53.
M. A. Bazanova D. F. Pyreu E. V. Kozlovskii 《Journal of Thermal Analysis and Calorimetry》2013,112(3):1545-1551
The mixed-ligand complex formation in the systems Cu2+–Edta4?–L (L = His, Lys, Orn, Arg, Im) has been calorimetrically, pH-potentiometrically, and spectrophotometrically studied in aqueous solution at 298.15 K and the ionic strength of I = 0.5 (KNO3). The thermodynamic parameters of formation of the CuEdtaL, CuEdtaHL, and (CuEdta)2L complexes have been determined. The probable coordination mode for the complexone and the ancillary ligand in the mixed-ligand complexes was discussed. 相似文献
54.
Mykhailo V. Klymenko Ivan M. Safonov Oleksiy V. Shulika Igor A. Sukhoivanov Rainer Michalzik 《Optical and Quantum Electronics》2008,40(2-4):197-204
In this paper, we have developed new design of the injector for quantum cascade structures based on the effective mass superlattice. The transmission spectra of the conventional injector and effective-mass injector have been compared. Advantage of the effective-mass injector is more uniform spectrum of pass-band. This feature allows to improve controllability of the quantum cascade laser, to increase stability of its operation and to decrease sensitivity to noise in applied voltage bias. Also, we have computed geometrical parameters for effective-mass injector which is appropriate to provide inverted population in existing quantum-cascade lasers. Such injector should be characterized by 15–25 numbers of layers with widths of layers up to 2 nm. 相似文献
55.
Use of time-of-flight mass spectrometry for monitoring helium microcontamination in the industrial manufacture of extra high purity inert gases 总被引:1,自引:0,他引:1
V. T. Zhdan A. V. Kozlovskii A. N. Mozhaev I. I. Pilyugin 《Journal of Analytical Chemistry》2010,65(14):1532-1536
A time-of-flight EMG-20-9 mass spectrometer was designed for the online monitoring of helium impurity at the 0.05 ppm level.
The spectrometer was introduced for the continuous control of the gas mixture composition in the technology of neon purification
from the helium impurity in spite of the large difference in the concentrations of components. The instrument was certified
as a measuring facility and introduced into the State Register of Measurement Instrumentation of the Russian Federation. The
characteristics of the mass spectrometer and its modifications were overviewed and its possibilities for monitoring xenon
and krypton production from air were shown. 相似文献
56.
T. S. Krivonogikh D. F. Pyreu E. V. Kozlovskii 《Russian Journal of Coordination Chemistry》2010,36(7):552-557
Mixed-ligand complexation of GdEdta− with glycinate, L-glutamate, DL-aspartate, iminodiacetate, and nitrilotriacetate anions in aqueous solutions at 298.15 K
and the ionic strength I = 0.5 (KNO3) was studied. The thermodynamic parameters (logK, Δ
r
G, Δ
r
H, Δ
r
S) of these reactions were determined from calorimetric and pH-metric data. The most probable way of coordination of the amino
acids in the heteroleptic complexes is discussed. 相似文献
57.
Halyna Shkil Leonard Stoica Kostyantyn Dmytruk Oleh Smutok Mykhailo Gonchar Andriy Sibirny Wolfgang Schuhmann 《Bioelectrochemistry (Amsterdam, Netherlands)》2009,76(1-2):175
In general, L-lactate respiration is difficult to detect in living yeast cells due to the small activity of L-lactate oxidizing enzymes within the mitochondria. Genetically modified cells of methylotrophic yeast Hansenula polymorpha overproducing L-lactate:cytochrome c-oxidoreductase (EC 1.1.2.3, also known as flavocytochrome b2, FC b2) were physically immobilized by means of a dialysis membrane onto various types of electrode materials in order to investigate the possibility of electrochemically detecting L-lactate respiration. It could be shown that in the case of genetically modified Hansenula polymorpha cells in contrast to cells from the parental strain, enhanced L-lactate-dependent respiration could be detected. Due to overproduction of FC b2 the O2 reduction current is decreased upon addition of L-lactate to the electrolyte solution. The electron transfer pathway in the L-lactate-dependent respiration process involves a cascade over three redox proteins, FC b2, cytochrome c and Complex-IV, starting with L-lactate oxidation and ending with oxygen reduction. By means of selective inhibition of Complex IV with CN−, lactate respiration could be proven for causing the decrease in the O2 reduction. 相似文献
58.
A. A. Kozlovskii D. A. Gordon V. A. Volodina A. I. Bol’shakov A. I. Mikhailov 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2010,84(8):1439-1444
The reactions of molecular chlorine with phenylacetylene (PA) and para-diethinylbenzene (p-DEB) at low temperatures (77–210 K) were studied by electronic paramagnetic resonance (EPR), size exclusion chromatography,
double bond analysis (DBA), calorimetry, and UV, visible, and IR spectroscopy. The low-temperature (100–210 K) reactions of
molecular chlorine without high-energy chemical (HEC) effects formed radicals capable of oligomerizations and polymerizations.
A readily soluble polymer para-diethinylbenzene having no spatial cross-linkages (but possibly having a branched structure) was obtained. Polymerization
occurred in direct contact with chlorine. It accelerated near the melting point (T
m) of chlorine and proceeded vigorously along with chlorination at T
m = 172 K. The occurrence of low-temperature polymerization without HEC treatment points to the high reactivity of the reagents.
From the viewpoint of applications, low-temperature oligomerization or polymerization of monomers with molecular chlorine
can afford oligomers or polymers with definite properties, which cannot be obtained by other initiation procedures. 相似文献
59.
Dmytro A. Yushchenko Mykhailo D. Bilokin’ Guy Duportail Vasyl G. Pivovarenko 《Tetrahedron letters》2006,47(6):905-908
A series of 2-aryl-3-hydroxyquinolones (3HQs) with different electron donating aryl substituents at the position 2 were synthesized. Their absorption and fluorescence properties were studied in solvents of medium and high polarity. Almost all the synthesized 3HQs display dual fluorescence in the tested solvents, in line with an excited state intramolecular proton transfer reaction. For N-methyl substituted compounds, the intensity ratio of the two emission bands was found to be exquisitely sensitive to solvent polarity, with a two orders of magnitude change from toluene to dimethylsulfoxide. Consequently, these compounds appear as prospective polarity fluorescent labels for proteins and nucleic acids. 相似文献
60.
A. V. Kozlovskii A. N. Oraevskii 《Journal of Experimental and Theoretical Physics》1999,88(6):1095-1101
The dynamics of the quantum-statistical properties of the radiation of an atom in a cavity interacting with an external coherent
field is investigated. A high level of quantum fluctuations of the field in the cavity is shown to destroy optical bistability
in the multiatom case. Photon-number fluctuations and the spectral dispersion of the canonically conjugate quadratures of
the field inside and outside a cavity are calculated. It is found that in contrast to the multiatom case quadrature squeezing
and squeezing of the radiation intensity of a single atom are negligible inside and outside the cavity.
Zh. éksp. Teor. Fiz. 115, 2001–2013 (June 1999) 相似文献