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91.
V. Rakhmanov A. L. Maximov A. V. Tarakanova Fam Vin’ Tkhay A. V. Anisimov 《Moscow University Chemistry Bulletin》2010,65(6):380-383
The electrospray ionization-mass spectrometry (ESI-MS) method has been used for determination of the structure of niobium peroxocomplexes. The formation of mono- and bisperoxocomplexes has been established. These complexes contain Schiff bases and 8-quinolinol as ligands. Trisperoxocomplexes are formed when pyridine and 1,10-phenanthroline are used. Peroxocomplexes with Schiff bases as ligands has shown a high activity as catalysts in the methylphenylsulphide oxidation. 相似文献
92.
T. D. Orlova A. V. Katrovtseva S. A. Bychkova Fam Tkhi Lan 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2011,85(2):225-228
The heat effects of complex formation between copper(II) ions and malonic, maleic, and succinic acids were measured in an
isothermic-shell calorimeter at 298.15 K and several ionic strength values against the background of NaNO3. The standard thermodynamic characteristics of complex formation in aqueous solutions were calculated. 相似文献
93.
Che Nin Man Noorjuliana Md Nor Razak Lajis Gam Lay Harn 《Journal of chromatography. A》2009,1216(47):8426-8430
Sildenafil and its analogues (tadalafil and vardenafil) are phosphodiesterase type 5 inhibitors used in the treatment of male erectile dysfunction. Some dietary supplements, herbal preparations and food products which claim to enhance male sexual function have been found to be adulterated with these drugs. In this study, a gas chromatograph–mass spectrometer (GC–MS) assay was developed for identification of the drugs. In addition to good and short chromatographic separation that can be achieved within 6 min by using a short 10 m capillary column, no prior sample clean-up before GC–MS analysis was required, thus making this assay a cost saving and rapid method. Furthermore, the assay is specific as the identification of sildenafil, tadalafil and vardenafil were done by detection of molecular ions; m/z 474, 389 and 448, respectively, and several other characteristic ions resulted from the mass fragmentation of individual molecules. Using our currently developed assay, sildenafil and its analogues were successfully identified in food and herbal matrices. 相似文献
94.
O. V. Dolgikh Vu Tkhi Zuen N. V. Sotskaya 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2009,83(6):939-944
The buffer properties of acetate, sulfate, and chloride glycine-containing electrolytes for nickel electroplating were studied. Various forms of the amino acid and background anions were shown to act in solution as two buffer systems related by competitive complex formation. The buffer capacity of a solution was then the result of the joint action of these systems. The contribution of each of them was determined by its absolute concentration in solution on the one hand and changes in this concentration caused by the addition of H+ or OH? ions on the other. 相似文献
95.
We studied quantitatively the photochemistry of solid O(3) and O(2) films at 193 nm and 22 K with infrared spectroscopy and microgravimetry. Photolysis of pure ozone destroyed O(3), but a small amount of ozone remained in the film at high fluence. Photolysis of pure O(2) produced O(3) in an amount that increased with photon fluence to a stationary level. For both O(2) and O(3) films, the O(3):O(2) ratio at large fluences is ~0.07, about two orders of magnitude larger than those obtained in gas phase photolysis. This enhancement is attributed to the increased photodissociation of O(2) due to photoabsorption by O(2) dimers, a process significant at solid-state densities. We obtain initial quantum yield for ozone synthesis from solid oxygen, Φ(O(3)) = 0.24 ± 0.06, and quantum yields for destruction of O(3) and O(2) in their parent solids, Φ(-O(3)) = 1.0 ± 0.2 and Φ(-O(2)) = 0.36 ± 0.1. Combined with known photoabsorption cross sections, we estimate probabilities for geminate recombination of 0.5 ± 0.1 for O(3) fragments and 0.88 ± 0.03 for oxygen atoms from O(2) dissociation. Using a single parameter kinetic model, we deduce the ratio of reaction cross sections for an O atom with O(2) vs. O(3) to be 0.1-0.2. The general good agreement of the model with the data suggests the validity of the central assumption of efficient energy and spin relaxation of photofragments in the solid prior to their reactions with other species. 相似文献
96.
Ly Tkhi Ien V. Yu. Khokhlov L. P. Bondareva L. I. Bel’chinskaya 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2012,86(5):849-851
Calorimetric measurements were performed and the heat effects of sorption of ammonium ions from aqueous solutions by the M45K20 natural sorbent and its acid- and alkali-activated forms were calculated. 相似文献
97.
98.
For a three-level atom interacting with two modes of the quantized radiation field the time dependence of transition operators, photon amplitudes, and of operators of level populations and photon numbers is examined rigorously. It is shown that the availability of a mode detuning leads to the splitting of the “soft branch” of frequencies of two-photon Rabi oscillations. 相似文献
99.
100.