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101.
Laila H. Abdel-Rahman Rafat M. El-Khatib Lobna A. E. Nassr Ahmed M. Abu-Dief 《Russian Journal of General Chemistry》2014,84(9):1830-1836
Kinetic study of some novel high spin Fe(II) complexes of Schiff base ligands derived from 5-bromsalicyaldehyde and amino acids with the OH? ion and DNA has been carried out. Based on the kinetic data, the rate law and a plausible mechanism were proposed. Kinetic data of the base catalyzed hydrolysis imply pseudo first-order double stage process due to the presence of mer- and fac-isomers. The observed rate constants k obs were correlated with the effect of a substituent R in the structure of ligands. The rate constants and activation parameters are in good agreement with stability constants of the studied complexes. Reactivity of the complexes towards DNA correlated well with the reported binding constants. 相似文献
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Rafat M. Mohareb Sherif M. Sherif Hosam El-Dean Moustafa 《Phosphorus, sulfur, and silicon and the related elements》2013,188(8):2078-2096
Abstract 2-Amino-7-oxotetrahydrobenzo[b]thiophenes 3a,b were prepared according to the Gewald procedure. Their reactivity toward a variety of chemical reagents was studied to give annulated heterocycles with potential bio-responses. 相似文献
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Rafat Husain Siddiqui 《Proceedings Mathematical Sciences》1940,11(4):268-281
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Eu (0.1, 0.5 and 1.0 mol%) doped Tb3Al5O12 (TAG) was prepared by sol–gel technique through nitrate-citrate route followed by sintering in air (1,100 °C maximum temperature).
XRD analysis showed that Eu3+ enters the TAG lattice substitutionally replacing the Tb3+ ion. Both XRD as well as FTIR investigation showed improvement in crystalline phase with the increase in the sintering temperature.
SEM and TEM analysis showed that the powder contains the particles in 5–20 nm size with almost spherical morphology. The excitation
spectrum recorded in 300–500 nm showed dominant absorption due to Tb3+ while the emission spectra recorded with 380 nm excitation had strong red emission characteristic of Eu3+. The intensity of this emission increases with the increase of the Eu concentration from 0.1 to 0.5 mol%. However, the emission
intensity decreased on further increase in Eu concentration to 1.0 mol%. This intensity variation with dopant concentration
is attributed to well-known “concentration quenching” observed in rare-earth doped materials. Reasonably strong red emission
due to Eu was observed when excited with the blue (480 nm) radiation of a Xe lamp indicating the usefulness of the material
for the realization of white light LED. 相似文献
110.
Much of previous work has been devoted in studying complete band gaps for bulk phononic crystal (PC). In this paper, we theoretically investigate the existence and widths of these gaps for PC plates. We focus our attention on steel rods of square cross sectional area embedded in epoxy matrix. The equations for calculating the dispersion relation for square rods in a square or a triangular lattice have been derived. Our analysis is based on super cell plane wave expansion (SC-PWE) method. The influence of inclusions filling factor and plate thickness on the existence and width of the phononic band gaps has been discussed. Our calculations show that there is a certain filling factor (f = 0.55) below which arrangement of square rods in a triangular lattice is superior to the arrangement in a square lattice. A comparison between square and circular cross sectional rods reveals that the former has superior normalized gap width than the latter in case of a square lattice. This situation is switched in case of a triangular lattice. Moreover, a maximum normalized gap width of 0.7 can be achieved for PC plate of square rods embedded in a square lattice and having height 90% of the lattice constant. 相似文献