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71.
In this paper, the authors first consider the global well-posedness of 3-D Boussinesq system, which has variable kinematic viscosity yet without thermal conductivity and buoyancy force, provided that the viscosity coefficient is sufficiently close to some positive constant in L∞and the initial velocity is small enough in B_(3,1)~0(R~3). With some thermal conductivity in the temperature equation and with linear buoyancy force θe3 on the velocity equation in the Boussinesq system, the authors also prove the global well-posedness of such system with initial temperature and initial velocity being sufficiently small in L~1(R~3)and B_(3,1)~0(R~3) respectively. 相似文献
72.
A mathematical model describing the discharge kinetics and lasing characteristics of copper bromide vapor laser with neon and hydrogen additives has been developed. The suggested model is based on a “zero-dimensional” model and offers simple mechanisms to explain discharge kinetics mechanisms, different physical processes and hydrogen additive effects on the copper bromide vapor laser.The model estimates the temporal evolution of discharge voltage and current, population densities, laser beam density, electron temperature and radial distribution of pressure and buffer gas temperature. The suggested mechanism assumes that the electron detachment from negative hydrogen ions does not contribute to the copper ionization process.Numerical solutions of a nonlinear rate equation system predict the generation of nanosecond pulses. The calculated maximum values of discharge voltage, current, average output laser power, electron temperature, etc. are in good agreement with other reported calculated and experimental data. 相似文献
73.
Measurements of electrical conductivities of liquid and supercooled liquid NaCl–glycerol solutions were carried out between +42° and ?87°C. Time-domain measurements of dielectric relaxation in pure glycerol and in NaCl–glycerol solutions between ?78 and ?89.9°C are described. The transient response data were fitted to the empirical Davidson–Cole response model. The specific conductivity data show a non-Arrhenius behavior near the glass-transition temperature and is well described by the Vogel–Tammann–Fulcher (VTF) law, which also fits the dielectric relaxation time data. The Vogel–Fulcher divergence temperature is consistent with the Kauzmann temperature. The dielectric relaxation time is increased significantly by the addition of sodium chloride, whereas the static relative permittivity decreases linearly with concentration, indicating that NaCl has a “structure-making” effect on the structure of glycerol. 相似文献
74.
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76.
On the basis of pulse-energy measurement of Nd–YAG laser emission, the reflection coefficient of complex mirror is determined as a function of pumping energy and resonator parameters. It is shown that the reflection coefficient of complex mirror has the tendency to stabilize with increasing pumping energy above the threshold energy. The practical interest of this work is to determine the reflection coefficient of resonant mirror without using calibrated mirrors. 相似文献
77.
Baklouti L Cherif J Abidi R Arnaud-Neu F Harrowfield J Vicens J 《Organic & biomolecular chemistry》2004,2(19):2786-2792
A series of mixed [2 + 2'] p-tert-butylcalix[4]arene have been synthesised by selective 1,3-dialkylation of phenolic groups using various alkylating agents such as benzyl bromide, methyl iodide, ethyl bromoacetate, and 2-methoxyethyl tosylate. The extraction and complexation properties of the synthesized calixarenes towards alkali and alkaline earth metal cations have been investigated in acetonitrile by means of UV spectrophotometry and 1H NMR spectroscopy. The results show the formation of ML and/or ML2 species depending on the ligand and the cation. The enthalpies and entropies of complexation of alkali metal cations by a tetraglycol, diglycol-dibenzyl and diglycol-diester derivatives have been obtained from calorimetric measurements. The results revealed that the formation of ML species is controlled by enthalpy while the formation of ML2 from ML is entropy driven. 相似文献
78.
Abidi Jamel 《Rendiconti del Circolo Matematico di Palermo》2002,51(3):411-424
Résumé On établira dans ce papier le lien biunivoque entre fonctios plurisousharmoniques et fonctions holomorphes.
We prove in this paper the connection between plurisubharmonic and holomorphic functions.相似文献
79.
An efficient, direct allylic amination of both cyclic and acyclic Morita–Baylis–Hillman alcohols with aromatic amines, in tetrahydrofuran (THF) at room temperature, catalyzed by Pd(0)/Et3B, is reported herein. The corresponding amines are obtained with a high α -regioselectivity in 65–87% yields. 相似文献
80.
L. U. Joshi M. D. Zingde S. A. H. Abidi 《Journal of Radioanalytical and Nuclear Chemistry》1983,79(2):317-323
The surface leaching of the labile component of uranium has been carried out in estuarine sediments of Zuari river in Goa. The measurements of alpha activities of238U,235U and234U in the leachates indicated a remarkable anomaly between the activities of238U and234U. The activity ratios of234U/238U in these leachates have been found to be in the range of 1.10 to 1.14. However, the activity ratios of235U/238U have been found to be 0.045 which is close to that in natural uranium. It has also been observed that the anomaly between238U and234U exists only on the surface organic layers of the backwater sediments of the Zuari river. 相似文献