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81.
Abraham F. Jalbout Ali Jameel Hameed Bartosz Trzaskowski 《Journal of organometallic chemistry》2007,692(5):1039-1047
A series of 1-(4, 5 and 6-selenenyl derivatives-3-formyl-phenyl) pyrrolidinofullerenes molecules C60-C2H4N-[3-(CHO)C6H3SeX] were investigated theoretically by performing Density Functional Theory calculations at the B3LYP/3-21G∗ level of the theory. The substituents include: X = CN, CH2CH(NH2)CO2H and CH2CH2CH(NH2)CO2H. We have selected these substituents to be in ortho, meta and para positions with relation to formyl group in order to show the effect of such structural change on the electronic properties of the molecules. The theoretical IR spectra, physical, chemical and thermodynamics properties of the molecules studied are obtained and discussed. 相似文献
82.
The electrode potentials of some quinone derivatives in aqueous solution have been calculated. The calculations are carried out at the Hartree–Fock and B3LYP levels with the inclusion of entropic and thermochemical corrections to yield free energies of redox reactions. The Polarisable Continuum Model (PCM) is used to describe the solvent. The average error of calculation of electrode potentials is less than 0.03 V and is decreased compared to the average error of methods presented previously. The role of relaxation energies and frequency calculations in improving the results has been investigated. 相似文献
83.
Vlachos P Mansoor B Aldred MP O'Neill M Kelly SM 《Chemical communications (Cambridge, England)》2005,(23):2921-2923
We report the design and synthesis of a liquid crystalline material exhibiting highly ordered smectic phases and high charge carrier-mobility; by a process known as "paramorphosis" highly ordered smectic phases can be transferred to the amorphous crystalline state on crystallisation without the formation of significant crystal grain boundaries and deep traps. 相似文献
84.
A novel design of Multiplexer–Demultiplexer (MUX–DEMUX) based on index guiding soft glass nematic liquid crystal (NLC) based
photonic crystal fiber coupler is proposed and analyzed. The simulation results are obtained using the full vectorial finite
difference method as well as the full vectorial finite difference beam propagation method. The numerical results reveal that
the proposed MUX–DEMUX of length 3.265 mm can provide low crosstalk better than −20dB with great bandwidths of 40 and 24 nm
around the wavelengths of 1.3 and 1.55 μm, respectively. In addition, the reported MUX–DEMUX has a tolerance of ±3% in its
length which makes the design more robust to the perturbation introduced during the fabrication process. 相似文献
85.
B3LYP and MP2 calculations with the commonly-used 6-31+G(d) basis set predict qualitatively different structures for the Tyr–Gly conformer book1, which is the most stable conformer identified in a previous study. The structures differ mainly in the ψtyr Ramachandran angle (138° in the B3LYP structure and 120° in the MP2 structure). The causes for the discrepant structures are attributed to missing dispersion in the B3LYP calculations and large intramolecular BSSE in the MP2 calculations. The correct ψtyr value is estimated to be 130°. The MP2/6-31+G(d) profile identified an additional conformer, not present on the B3LYP surface, with a ψtyr value of 96° and a more folded structure. This minimum is, however, likely an artefact of large intramolecular BSSE values. We recommend the use of basis sets of at least quadruple-zeta quality in density functional theory (DFT), DFTaugmented with an empirical dispersion term (DFT-D) and second-order Møller-Plesset perturbation theory (MP2 ) calculations in cases where intramolecular BSSE is expected to be large. 相似文献
86.
Muhammad Aslam Noor Khalida Inayat Noor Mahmood-ul-Hassan 《Applied mathematics and computation》2007,190(2):1551-1556
In this paper, we suggest and analyze a new two-step iterative method for solving nonlinear equations, which is called the modified Householder method without second derivatives for nonlinear equation. We also prove that the modified method has cubic convergence. Several examples are given to illustrate the efficiency and the performance of the new method. New method can be considered as an alternative to the present cubic convergent methods for solving nonlinear equations. 相似文献
87.
Ijaz M. Nadeem S. Ayub M. Mansoor S. 《Journal of Thermal Analysis and Calorimetry》2021,143(3):2053-2067
Journal of Thermal Analysis and Calorimetry - The present paper explores the features of thermal radiation on ferromagnetic Jeffrey fluid flow within the frame of gyrotactic microorganisms and... 相似文献
88.
Abdul Karim‐Talaq Mohammad Abdullah Thamer Hameed Mohammed Affan Alhamdany Khaldun Mohammad Al Azzam Gaidaa Abd Alkareem Talk 《Biomedical chromatography : BMC》2019,33(4)
A method for digestion of light and medium Iraqi crude oils (Basrah and Khanaken oils) using microwave‐induced combustion (MIC) in closed vessels is described for the determination of Hg, Au, Cu, Al, Ca, Co, K, Mg, Si and Sr by inductively coupled plasma optical emission spectrometry (ICP–OES) and Mo, Ti, Mn, Li, Se?1, Rb, Ag, Ba, Pb, As, Cd, Cr, Fe, Ni, V and Zn by inductively coupled plasma mass spectrometry (ICP–MS). Upon using MIC it was possible to obtain lower limits of detection by ICP–MS and also by ICP–OES compared with those obtained by microwave‐assisted digestion. The MIC was the best choice with regard to the possibility of using dilute nitric acid as an absorbing solution, which is important to minimize the interference encountered by ICP–MS and ICP–OES.The physicochemical parameters and some contaminants of crude oil samples were analyzed to classify and assess the quality of the crude oils. This study determines the viability of the use of Fourier transform infrared spectroscopy as an alternativee to traditional petroleum geochemical methods for crude oil characterization. The infrared fingerprints agree with the results obtained from GC–MS analysis. 相似文献
89.
Advances in Data Analysis and Classification - In recent years dictionary learning has become a favorite sparse feature extraction technique. Dictionary learning represents each data as a sparse... 相似文献
90.
Energy transport in silicon–aluminum composite thin films due to short-pulse laser irradiation is examined. Frequency dependent phonon transport in the silicon film is considered to formulate equivalent equilibrium temperature while modified two-equation model is used in the aluminum film to obtain electron and phonon temperatures. Thermal boundary resistance across the films is incorporated in the analysis. Transmittance, reflectance, and absorption of the incident laser beam are determined using the transfer matrix method. Equivalent equilibrium temperatures resulted from frequency dependent and frequency independent solutions are compared. It is found that phonon temperature increase at the aluminum interface is suppressed by phonon transport to the silicon film, which is more pronounced at low laser pulse intensities. The influence of the ballistic phonons on equivalent equilibrium temperature in the silicon film is found to be significant. 相似文献