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61.
M. O. Kazakov A. V. Lavrenov I. G. Danilova O. B. Belskaya V. K. Duplyakin 《Kinetics and Catalysis》2011,52(4):573-578
The acidic and hydrogenating of Pt/SO42−-ZrO2-Al2O3 samples containing from 18.8 to 67.8 wt % Al2O3 as a support constituent were studied by the IR spectroscopy of adsorbed CO and pyridine, and the model reactions of n-heptane and cyclohexane isomerization on these catalysts were examined. The total catalyst activity in the conversion of
n-heptane decreased with the concentration of Al2O3; this manifested itself in an increase in the temperature of 50% n-heptane conversion from 112 to 266°C and in an increase in the selectivity of isomerization to 94.2%. In this case, the maximum
yield of isoheptanes was 47.1 wt %, which was reached on a sample whose support contained 67.8 wt % Al2O3. A maximum yield (69.6 wt %) and selectivity (93.7%) for methylcyclopentane formation from cyclohexane were also reached
on the above catalyst sample. This can be explained by lower concentrations of Lewis and Br?nsted acid sites in the Pt/SO42−-ZrO2-Al2O3 system, as compared with those in Pt/SO42−-ZrO2. The experimental results allowed us to make a preliminary conclusion that the Pt/SO42−-ZrO2-Al2O3 catalyst whose support contains 67.8 wt % Al2O3 is promising for use in the selective hydroisomerization of benzene-containing gasoline fractions in the thermodynamically
favorable process temperature range of 250–300°C. 相似文献
62.
V. N. Prudnikov A. P. Kazakov I. S. Titov Ya. N. Kovarskii N. S. Perov A. B. Granovsky I. Dubenko A. K. Pathak N. Ali J. Gonzalez 《Physics of the Solid State》2011,53(3):490-493
The quasi-diamagnetism effect that manifests itself in the negative magnetic susceptibility observed in weak magnetic fields
during cooling of samples below some critical temperature has been revealed in Ni48Co2Mn35In15 Heusler alloys. The effect has been attributed to a strong nonequilibrium of the system due to the presence of magnetic and
structural disorders and exchange anisotropy. 相似文献
63.
Gonnelli RS Daghero D Ummarino GA Stepanov VA Jun J Kazakov SM Karpinski J 《Physical review letters》2002,89(24):247004
We present the results of the first directional point-contact spectroscopy experiments in high-quality MgB2 single crystals. Because of the directionality of the current injection into the samples, the application of a magnetic field allowed us to separate the contributions of the sigma and pi bands to the total conductance of our point contacts. By using this technique, we were able to obtain the temperature dependency of each gap independent of the other. The consequent, strong reduction of the error on the value of the gap amplitude as a function of temperature allows a stricter test of the predictions of the two-band model for MgB2. 相似文献
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A. D. Karavaev A. I. Voloshin V. P. Kazakov 《Theoretical and Experimental Chemistry》1989,25(2):174-179
It has been shown that the red chemiluminescence (CL) in the Belousov-Zhabotinskii system with Mn(II, III) cannot be attributed to the formation of excited oxygen or its dimers during the process. Chemiluminescence has been discovered upon the reduction of Mn(III) by malonic acid, and its spectrum coincides with the spectrum of the CL in the oscillatory system (with a maximum at 680–720 nm) and is found in the same region as the photoluminescence of Mn(II),- which is known from the literature data. It has been concluded that the principal emitter of the oscillatory CL is Mn(II), which is formed in an excited state upon the reduction of Mn(III).Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 25, No. 2, pp. 191–197, March–April, 1989. 相似文献
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