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991.
Chemical kinetics of benzonitrile nitration with mixed acid is investigated in the temperature range 283–299 K. Pseudo-first-order rate constants are evaluated by means of rate experiments on homogeneous reacting mixtures having large stoichiometric excesses of nitric acid. The second-order kinetic constants for nitronium ion attack to the aromatic substrate are derived on the basis of the assessed nitration mechanism. An activation energy of 604 ± 37 kJ mol?1 is calculated for this reaction step. © 1993 John Wiley & Sons, Inc. 相似文献
992.
The contributions to the coefficient functions of the quark and the mixed quark-gluon condensate to mesonic correlators are calculated for the first time to all orders in the quark masses, and to lowest order in the strong coupling constant. Existing results on the coefficient functions of the unit operator and the gluon condensate are reviewed. The proper factorization of short- and long-distance contributions in the operator product expansion is discussed in detail. It is found that to accomplish this task rigorously the operator product expansion has to be performed in terms ofnon-normal-ordered condensates. The resulting coefficient functions are improved with the help of the renormalization group. The scale invariant combination of dimension 5 operators, including mixing with the mass operator, which is needed for the renormalization group improvement, is calculated in the leading order.Supported by the German Bundesministerium für Forschung und Technologie, under the contract 06 TM 761 相似文献
993.
The hyperfine field andthe electric field gradient on Cd probe atoms at Ni(100) and Ni(111) surfaces are calculated self-consistently within the local density molecular/cluster approach. 相似文献
994.
An iterative method from the class of completely implicit methods (CIM) is proposed for solving the equation of the velocity
potential of elliptical-hyperbolic type. The advantage of the proposed method compared to other CIM schemes is demonstrated
in application to mixed perfect gas flows in a nozzle of a given shape. Accuracy issues, rate of convergence, and various
techniques of ensuring stability in the hyperbolic region are discussed.
Translated from Chislennye Metody v Matematicheskoi Fizike, Published by Moscow University, Moscow, 1996, pp. 39–51. 相似文献
995.
A. P. Krauklis 《Journal of Mathematical Sciences》1997,86(3):2702-2704
This paper justifies the necessity of introducing corrections for the ray curvature into the standard procedure of the tomographic
inversion in the case of using traveltime data for the creeping waves. The results of relevant numerical experiments are presented.
Bibliography: 3 titles.
Translated fromZapiski Nauchnykh Seminarov POMI, Vol. 218, 1994, pp 67–71.
This work was supported by the Russian Foundation of Fundamental Research (Grant 93-05-9961).
Translated by A. P. Krauklis. 相似文献
996.
997.
998.
We show that the LF-algebra considered by Akkar and Nacir in [1] is topologically simple. 相似文献
999.
1000.
This research extends previous work with dynamic models to manage groundwater quality by using the consumptive nitrate use rate instead of the nitrate application rate. The analysis indicates that misspecification results in overestimation of economic benefits, and supra-optimum nitrogen fertilizer application rates and groundwater nitrate stocks at a steady state. 相似文献