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181.
Abstract Experimental and theoretical (INDO-MO) studies of n → transitions have been carried out for seven symmetric diazines. In all cases, there is very good agreement between the theoretical predictions and experimental observations on the symmetry of the lowest energy n→? singlet state. 相似文献
182.
Özlem Yeşiltaş 《Central European Journal of Physics》2013,11(12):1674-1679
In this paper, we have provided a matrix Hamiltonian model for honeycomb lattices and subsequently obtained the dispersion relation. Furthermore, we have constructed the C operator for the given non-Hermitian Hamiltonian model. The quadratic surfaces are sketched and the quantum Brachistochrone problem is discussed for the given honeycomb lattice model. 相似文献
183.
A Curşeu T van Woensel J Fransoo K van Donselaar R Broekmeulen 《The Journal of the Operational Research Society》2009,60(2):200-214
Shelf stacking represents the daily process of manually refilling the shelves with products from new deliveries. For most retailers, handling operations are labour-intensive and often very costly. This paper presents an empirical study of the shelf-stacking process in grocery retail stores. We examine the complete process at the level of individual sub-activities and study the main factors that affect the execution time of this common operation. Based on the insights from different sub-activities, a prediction model is developed that allows estimating the total stacking time per order line, solely on the basis of the number of case packs and consumer units. The model is tested and validated using real-life data from two European grocery retailers and serves as a useful tool for evaluating the workload required for the usual shelf-stacking operations. Furthermore, we illustrate the benefits of the model by analytically quantifying the potential time savings in the stacking process, and present a lot-sizing analysis to demonstrate the opportunities for extending inventory control rules with a handling component. 相似文献
184.
185.
Nonlinear Dynamics - Substitution Box (S-Box) is one of the most significant structures used to create an encryption which is strong and resistant against attacks in block encryption algorithms.... 相似文献
186.
Metin Ak Gülbanu Koyundereli Çılgı Ferah Diba Kuru Halil Cetişli 《Journal of Thermal Analysis and Calorimetry》2013,111(2):1627-1632
Thermal behavior of 2,4,6-tris(4-(1H-pyrrol-1-yl)phenoxy)-1,3,5-triazine monomer, polypyrrole, and their star shaped copolymer, were investigated using TG and DTA methods. It was found that Tria melts at 517 K and after than it starts to decompose. Decomposition proceeded in two stages which were corresponding to removal of branched groups and remaining core structure degradation, respectively. Polypyrrole and copolymer showed similar thermal behaviors. These compounds decomposed in three stages which are removal of solvent, removal of dopant anion and rest of structure decomposition. The calculation of activation energies of all reactions were realized using model-free (KAS and FWO) methods. The graphs were prepared which show the alteration of activation energy with decomposition ratio. Thermal analysis results showed that dopant anion and solvent removal activation energy values for copolymer are lower than polypyrrole. Star shaped loose-packed novel structure greatly facilitates solvent and dopant anion removal from copolymer. It can be concluded also that thermal analysis can be used as predict package structure of conducting polymers. 相似文献
187.
A new reagent for spectrophotometric determination of Mo(VI) was developed utilizing micellar effects. For this purpose, differences
in the ultraviolet and visible spectral properties of Mo(VI), gallic acid, L-serine, and their binary and ternary solutions were studied in the presence and absence of cationic, anionic, and non-ionic
surface active agents. L-serine was observed to form binary complexes and a ternary complex with Mo(VI) and gallic acid below its isoelectric point.
The maximum Mo(VI) sensitivity was exerted by the Mo(VI) + gallic acid + L-serine + hexadecyltrimethylammonium bromide system at pH of 4.5. This system was proposed for use in the spectrophotometric
determination of Mo(VI) as a superior alternative to the Mo(VI) + gallic acid + hexadecyltrimethylammonium bromide system
and to most of the instrumental analysis methods referred to in the literature. The mechanism of micellar effects was discussed
on the basis of the spectral data obtained above and below the isoelectric point of L-serine and explained in terms of the molecular charge of the substrates and the surfactants. 相似文献
188.
László Csaba Bencze Csaba Paizs Monica Ioana Toşa Maria Trif Florin Dan Irimie 《Tetrahedron: Asymmetry》2010,21(16):1999-2004
A highly stereoselective enzymatic kinetic resolution of novel various substituted racemic furylbenzthiazole-2-yl-ethanols and their acetates has been developed. Both processes, the enzymatic acylation of the racemic alcohols and the enzymatic methanolysis of racemic acetates yielded highly enantiomerically enriched (ee >98%) resolution product, when CaL-B was used as a biocatalyst in acetonitrile. The absolute configuration of the obtained (R)-(+)-1-(5-(4-chlorobenzo[d]thiazol-2-yl)furan-2-yl)ethanol was determined by a detailed 1H NMR study of rac- and (+)-1-(5-(4-chlorobenzo[d]thiazol-2-yl)furan-2-yl)ethanol Mosher derivatives. 相似文献
189.
The possibilities of preparing a packing for reversed phase column chromatography from Menderes' perlite were studied. Its
physical and chemical characteristics were compared with other solid supports prepared from rocks, such as perlite and volcanic
slags. A series of chemical treatments were applied to improve the mechanical and chemical properties of perlite. The experimental
work covers the strong acid treatment, the strong base treatment and the silanization with DMCS. The raw perlite containing
70–73% SiO2 was treated with NaOH to make soluble silicates and to increase it. Thus the surface and mechanical characters of the modified
perlite were determined. The mean surface OH group density and the specific surface area were 3.2 μmol/m2 and 9.2 m2/g, respectively. The modified perlite was silanized and hydrophized to load organic complexing agents. The TBP was fixed
successfully on perlite up to 20% w/w. The packing prepared was used to study the chromatographic behavior of UO2
2+ Fe3+. 相似文献
190.
H. Taşeli 《Journal of mathematical chemistry》1996,20(2):235-245
The series solution of theN-dimensional isotropic quartic oscillator weighted by an appropriate function which exhibits the correct asymptotic behavior of the wave function is presented. The numerical performance of the solution in Hill's determinant picture is excellent, and yields the energy spectrum of the system to any desired accuracy for the full range of the coupling constant. Furthermore, it converges to the well-known exact solution of the unperturbed harmonic oscillator wave function, when the anharmonic interaction vanishes. 相似文献