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101.
Hamid R. Memarian Majid M. Sadeghi Ahmad R. Momeni Dietrich D?pp 《Monatshefte für Chemie / Chemical Monthly》2002,9(4):661-667
Some novel 3,5-diacetyl-1,4-dihydropyridine derivatives were synthesized; their photochemical behaviour was studied under oxygen or argon atmosphere. Irradiation of these compounds resulted in the aromatization of the ring and formation of 3,5-diacetylpyridine derivatives. The presence of oxygen plays an important role in the type, rate, or failure of oxidation. Irradiation of these compounds with of 2-furyl or 5-methyl-2-furyl substituents in position 4 under argon resulted in the formation of a pyridine ring with retention of these substituents, whereas loss of these substituents and ring aromatization was observed upon irradiation under oxygen. 相似文献
102.
The electrolyte NRTL model [C.C. Chen, L.B. Evans, AIChE J. 32 (1986) 444–454] and electrolyte Wilson model [E. Zhao, M. Yu, R.E. Sauvé, M. Khoshkbarchi, Fluid Phase Equilibr. 173 (2000) 161–175] have been extended for the representation of the dynamic viscosity of strong electrolyte solutions. The models are based on Eyring's absolute rate theory and the electrolyte NRTL and Wilson models for calculating the excess Gibbs energy of activation of the viscous flow. The utility of the models is demonstrated with a successful representation of the viscosity of several electrolyte solutions at different temperatures. The results show that, the model is valid for the whole range of salt concentration and it is reliable for correlation of the viscosity of electrolyte solutions at different temperatures by only four adjustable parameters per binary system. 相似文献
103.
Atmospheric electricity measurements made during the last decade at Poona using balloon-borne sondes are briefly reviewed. The vertical distribution of potential gradient in the free atmosphere follows theoretical values only during the monsoon months, when the air is comparatively free from dust. During the summer months, the potential gradient is constant above the exchange layer and this is associated with the presence of the deep, dense dust layer that lies over the region and extends to over 10 km. into the atmosphere. The increase with height of the potential gradient above the 10 km. level during winter is shown to be closely related to the presence of the subtropical jet stream, which presumably transports electric charges to the upper levels over Poona. 相似文献
104.
P. G. Adyalkar V. V. Rane V. V. S. Mani J. P. Dias 《Proceedings Mathematical Sciences》1975,81(3):108-117
The paper attempts to evaluate the permeability data obtained from 75 aquifer performance tests conducted on open wells tapping the water table aquifer of the basaltic lava flows spread over the three different basins of Maharashtra. The permeability has been computed by Thiem’s formula and the modified Theis non-equilibrium formula. The statistical analysis of the permeability data of the study basins,viz., Bhima, Godavari and Wardha, reveal a decrease in permeability range as one proceeds from the Bhima basin (low rainfall area) through the Godavari basin (assured rainfall area) to the high rainfall area of Wardha basin. The permeability frequency graphs of the three study basins reveal different hydrogeological characteristics for each. 相似文献
105.
Using the light absorption technique in a 132Xe afterglow plasma, we have measured the relative transition probabilities for several xenon lines which have the metastable 6s[]2 or the resonant 6s[]1 states as their lowest transition level. Because the transition probabilities of the 8819 Å (6p[]3 ? 6s[]2) and 8280 Å (6p[]0 ? 6s[]1) lines are relatively well known, we have chosen these as reference lines and have thus been able to determine the absolute values of the transition probabilities for 19 xenon lines corresponding to transitions from 6p, 6p′, 7p, 8p, 9p, 4f and 5f to 6s[]2, and for four lines corresponding to the transitions 6p?6s[]1. 相似文献
106.
107.
108.
Quantum chromodynamics corrections to orderα
s (the running coupling constant), using the quark-parton approach are calculated for the spin-dependent structure functions
in deep-inelastic polarised electron-nucleon scattering. Consequences of these corrections for the Bjorken sum rule and the
asymmetry in the case of longitudinally polarised (with respect to the beam) nucleons is discussed which could provide possible
tests of quantum chromodynamics. Comparison of our results with the moments of the flavour non-singlet contribution to the
structure functions obtained using operator product expansion is also given.
An erratum to this article is available at . 相似文献
109.
The excitation-transfer reaction in thermal energy collisions of state-selected metastable Ar*(3P2) and Ar*(3P0) atoms with ground state H atoms, giving excited H*(n = 2) atoms, has been studied with the stationary afterglow technique. The rate constant for the excitation of H atoms by Ar*(3P2) has been found to be more than one order of magnitude larger than in excitation by Ar*(3P0). This difference in the reactivity of two metastable species is explained to be a consequence of the attractive nature of the D(2II) and E(2Σ+) potentials that develop from the Ar*(3P2)+H entrance channel and which give curve crossing with the B(2II) and C(2Σ+ potentials, respectively, leading to the Ar+H*(n=2) exit channel, whereas only a repulsive 4II (Ω=) potential develops from the Ar*(3P0+H entrance channel. 相似文献
110.
Effective field theory (EFT) has been recently used for the calculation of neutron–deuteron radiative capture at very low
energies. We present here the use of EFT to calculate the two-body photodisintegration of the triton, considering the three-body
force. The calculated cross section shows sharp rising from threshold to maximum about 0.88 mb at ~13 MeV and decreasing slightly
to about 0.81 mb at ~19 MeV, in agreement with the experimental data. Our results are in good agreement with the experimental
data and the other calculations using modern realistic two- and three-nucleon forces, like AV18/UrbanaIX potential. 相似文献