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991.
The selectivity of the oxides under consideration to the oxidation of methanol to formaldehyde is shown to increase in the sequence V2O5–Nb2O5–Ta2O5. The same sequence corresponds to the decrease in specific activity. The activation energy of the reaction is 12 kcal/mol for V2O5, 14 kcal/mol for Nb2O5 and 22 kcal/mol for Ta2O5.
, V2O5–Nb2O5–Ta2O5. . : V2O5 12 /, Nb2O5 14 / Ta2O5 22 /.相似文献
992.
T. M. Gairbekov Ya. S. Yakhyaev S. N. Khadzhiev 《Reaction Kinetics and Catalysis Letters》1986,31(1):127-131
Regularities in n-hexane conversion on decationized Y zeolites under cracking and aromatization conditions have been studied. Possible formation of lower olefins and benzenes in parallel reactions following different mechanisms at low conversion degrees is suggested. The effect of thermosteam treatment on the activity and selectivity of Y zeolites in n-hexane conversion has been examined.
- Y . , . Y -.相似文献
993.
Summary The semi-empirical theory on the retention volume in gas chromatography recently developed by some experiments, was found to require partial correction. It was newly refined and summarized. Overall experimental checking was performed by the use of Cl2, Br2, and I2.
Gas-Chromatographie von Halogenen
Zusammenfassung Die halbempirische Theorie über das Retentionsvolumen in der Gas-Chromatographie, die kürzlich an Hand einiger Versuche entwickelt wurde, erforderte eine teilweise Korrektur. Sie wurde verbessert und zusammenfassend dargestellt. Kontrollversuche wurden mit Hilfe von Chlor, Brom und Jod durchgeführt.相似文献
994.
M. Kuzmanovi M. A. Khakoo V. Bojovi A. Anti-Jovanovi 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2007,81(9):1438-1442
An array of Franck-Condon factors and r-centroids is reported for the bands of the E
1Πu-X
1Σ
g
+
system of the Ag2 molecule. Both parameters were calculated using the Morse and Rydberg-Klein-Rees potentials. The results showed a reasonable
agreement between the two sets of data for transitions, including lower vibrational levels (v ≤ 6). Differences appear with increasing v, but two sets of calculated Franck-Condon factors follow the same pattern. The predicted intensity distribution was compared
with the estimated band intensity in the experimental spectrum.
The text was submitted by the authors in English. 相似文献
995.
Maria-Teresa Clavaguera-Mora Narcís Clavaguera Javier Rodríguez-Viejo 《Monatshefte für Chemie / Chemical Monthly》2005,12(8):1947-1953
The primary crystallization of molten alloy systems at high undercooling is studied by a precise quantitative analysis of
the calorimetric signal obtained during the transformation in terms of the reaction rate under isothermal and continuous heating
regimes. It is shown that, under specific conditions, namely, stoechiometric primary precipitates, generalized relationships
for the crystallization enthalpy and the reaction rate may be obtained. 相似文献
996.
Joeng-Shein Chen Harald Berndt Günther T?lg 《Fresenius' Journal of Analytical Chemistry》1992,344(12):526-534
Summary Various possibilities for the determination of trace impurities in high-purity iron by atomic spectrometry were investigated in detail. For Ba, Bi, Cd, Co, Cr, Cu, Mn, Ni, Pb, Ti and V, flame AAS, furnace AAS and ICP-OES were firstly evaluated in terms of their power of detection. Detection limits in the g/g-range could be achieved by direct determination. For determination in the ng/g-range a removal of iron by a solvent extraction technique prior to the instrumental measurement was required. The power of detection of direct determination, and of combined procedures were compared with regard to routine applicability and a minimization of systematic errors. 相似文献
997.
998.
999.
The liquid-phase C-alkylation of hidroquinone with isobutene catalyzed by heteropoly acids H3PW12O40, H6P2W18O62 and H6P2W21O71 (HPA) under phase-transfer conditions in a two-phase system, including toluene (upper phase) and HPA dioxane etherate, HPA·xC4H8O12·yH2O, (lower phase) has been studied. 相似文献
1000.
Y. E. Kutsovsky A. G. Mariasov Y. I. Aristov V. N. Parmon 《Reaction Kinetics and Catalysis Letters》1990,42(1):19-24
The ESE method was successfully used for investigating the texture of the adsorbents and catalysts. Equations were obtained for the kinetics of ESE signal decay due to dipole-dipole interaction between motionless paramagnetic centers distributed uniformly on the fractal surface of solid.
, . , , .相似文献