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A simplified form of the first-order many-body theory was used for the calculation of the coherence and correlation parameters for the excitation of the 21 P and 31 P states of helium. The excited state wave functions were calculated numerically in the fixed core Hartree-Fock(HF) approximation. The ground state wave function was used in the HF approximation. Scattering orbitals were calculated numerically in the static exchange approximation. Calculations were performed forE=29.6, 40, 50, 60 and 80 eV impact energies for the 21 P state, and forE=50 eV and 80 eV for the 31 P state. Results for the coherence and correlation parameters are compared with the experimental values obtained from electronphoton coincidence experiments, and with other theoretical results. 相似文献
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The electrochemical reduction of antifouling agent 2-thiocyanomethylthiobenzothiazole (TCMTB) was investigated by cyclic and pulse differential voltammetry. The irreversible electrode reduction of TCMTB proceeded by ECEC reaction mechanism by two electrons transfer with one irreversible wave. Upon the basis of electrochemical evidence, the electrodic reaction mechanism was suggested to formation of mercaptobenzothiazole (MTB) in solution.Subsequently, a pulse differential method is described for the formation of TCMTB based on this electroreduction. Having been obtained a detection limit of 1.0 × 10−7 mol L−1 and recovery to 98% to concentration of 2.0 × 10−6 mol L−1. Therefore, the proposed method in this study is practical, sensitive and accurate for the analysis of TCMTB in tannery wastewater samples. 相似文献
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G. D. Meneses L. M. Brescansin M. -T. Lee S. E. Michelin L. E. Machado G. Csanak 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1994,30(2):173-175
We have applied the density matrix formalism and the distorted-wave approximation to calculate the Stokes parameters for thed 3 Π u ? (v=0,1,2,3;N=1) states of H2 excited from the X1 ∑ g + (v=0,N=1) state by electron impact at the incident energies ranging from 15 to 40 eV. Our results show that these parameters are nearly independent of the vibrational quantum number of the excited states. However, the polarization of the radiation emitted by the target in the subsequent decay process increases with increasing incident energies. 相似文献
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Thomas Glonek Patricio Meneses 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-4)
Abstract Cell membrane phospholipids can be identified and quantitated using 31P NMR spectroscopy in conjunction with an analytical reagent composed of chloroform-benzene(d6)/methanol-CsEDTA 2:l ml/ml. 3 ml of this reagent dissolves between 0.01–100 mg crude tissue lipids obtained by the Folch procedure. When the source phospholipids are strongly contaminated with cations, it is necessary to modify the extraction method, backwashing with K-EDTA, 0.6 M, pH 6, instead of KC1. Also if source tissues must be stored for long periods of time, acetone desication is recommended. Using a 500 MHz 31PNMR spectrophotometer (magnetic field ?11.75 T), the extracted phospholipids yield narrow Lorenzian signals (1.8–3.2 Hz at half-height), with these widths at half-height corresponding to their 1/πT2 values. Chemical shifts (δ) at 24 °C, following the IUPAC shift convention and relative to 85% phosphoric acid, were determined as follows:CAEP,21.09;LPG,l,O9;LPA,0.83;LPE plas,0.53;PG,0.50;LPE,0.43; PA,0.25;CL,0.18;LPI,0.10;PE plas,0.07;PE,0.03;PS,?0.O5;SPH,?0.O9; DiMePE,?b.18;LPC plas,?0.20;LPC,?0.28;PI,?0.37; PAF, ?0.70;PC plas,?0.77; PC, ?0.84. This reagent permits assays of high precision and accuracy that use little spectrometer time and that are suitable for automated procedures. 相似文献
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Lidiane Pinto Correia Elisana Afonso de Moura Hallisson Meneses Pires Rui Oliveira Macêdo 《Journal of Thermal Analysis and Calorimetry》2011,106(2):459-461
Water is a fundamental element of life. Its multiple uses are indispensable for a wide spectrum of human activities. This
study aims to characterize water from different salinities obtained in the Cariri region of Paraíba, Brazil. The samples were
analyzed using the DSC-coupled to the Peltier system (DSC-Cooling) and physical–chemical water tests performed employing reactive
kits, using the Spectroquant Merck? specific for each test. The calorimetric curves showed crystallization phase transitions with different characteristics in
peak format and crystallization temperatures between the samples of different salinities. The calorimetric data obtained in
the process of crystallization of water is directly correlated to the physico-chemical parameters of conductivity and total
dissolved solids, showing that the analytical technology DSC-cooling/heating is suitable for characterization of different
salinities water. 相似文献
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We consider the effect of the interaction among photoinjected electrons, on the radiative emission spectra of semiconductors. The observed shift of the photoluminescence spectra, at high excitation levels, towards lower energies is accounted for by the present calculation. 相似文献
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Rodrigo Meneses 《Journal of Mathematical Analysis and Applications》2011,376(2):514-527
In this paper, we prove that a class of parabolic equations involving a second order fully nonlinear uniformly elliptic operator has a Fujita type exponent. These exponents are related with an eigenvalue problem in all RN and play the same role in blow-up theorems as the classical p?=1+2/N introduced by Fujita for the Laplacian. We also obtain some associated existence results. 相似文献
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Methyl (8R,13S)-8α,13:13,17-diepoxy-14,15-dinorlabdane-19-oate, easily prepared from communic acids, is a suitable intermediate for synthesizing pentacyclic quassinoids, because it enables the elaboration of the A ring and the further construction of the B-C-D ring system of these terpenoids. The cetal group is stable under the reaction conditions utilized during the elimination of the ester group and the introduction of the hydroxyl group on C-3. At the same time, it enables the regeneration of the methylketone and exocyclic double bond presented by methyl 13-oxo-14,15-dinorlabd-8(17)en-19-oate. The latter compound was previously used to construct the B-C-D-ring of these quassinoids. 相似文献