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51.
H.S.Abdel-Aziz 《理论物理通讯》2004,42(5):672-674
In this contribution, my main attention is paid to the study of the geometric phase of a two-level system.Asymptotic expansion of the eigenvalue and analytic information are obtained. The results are illustrated with an application to a specific atomic system. 相似文献
52.
Nehal A. Hamdy Hatem A. Abdel-Aziz Ahmad M. Farag Issa M. I. Fakhr 《Monatshefte für Chemie / Chemical Monthly》2007,60(4):1001-1010
3-(3-Methylthiazolo[3,2-a]benzimidazol-2-yl)-3-oxopropionitrile was synthesized by refluxing ethyl 3-methylthiazolo[3,2-a]benzimidazole-2-carboxylate, acetonitrile, and sodium hydride. Treatment of 3-(3-methylthiazolo[3,2-a]benzimidazol-2-yl)-3-oxopropionitrile with phenyl isothiocyanate, in the presence of KOH, furnished the corresponding potassium
salt which was converted into thioacetanilide derivative upon neutralization. The thioacetanilide derivative reacts with α-chloroacetylacetone
and ethyl α-chloroacetoacetate to give the 1,3-thiazole derivatives, while the reaction of the'thioacetanilide derivative
with hydrazonyl chlorides gave 1,3,4-thiadiazole derivatives. On the other hand, 3-(3-methylthiazolo[3,2-a]benzimidazol-2-yl)-3-oxopropionitrile reacted with the diazonium salt of both 3-phenyl-5-amino-(1H)-pyrazole and 5-amino-l,2,4-(1H)-triazole to afford the corresponding hydrazones. The latter hydrazones underwent an intramolecular cyclization upon boiling
in pyridine to give pyrazolo[5,1-c]-1,2,4-triazine and 1,2,4-triazolo[5,1-c]-1,2,4-triazine derivatives. Moreover, the behavior of thiazolo[3,2-a]benzimidazol-3(2H)-one towards phenyl isothiocyanate followed by the reaction with α-chloroketones or hydrazonyl chlorides was investigated.
Some of the latter compounds exhibited moderate effects against some bacterial and fungal species. 相似文献
53.
A. A. Abd El Raheem Abdel-Aziz M. Amin 《Fresenius' Journal of Analytical Chemistry》1958,163(5):340-344
Summary The use of eriochrome blue S. E. as a metal indicator for the EDTA titrations of zinc, cadmium, magnesium, lead, nickel and manganese is described. Spot tests for the determination of the sensitivity limits of dectection of the end points are given. 相似文献
54.
Summary The use of Omega Chrome Black PPV for the EDTA titration of zinc, manganese, nickel, cadmium, magnesium and lead is described. The sensitivity limits of detection of the equivalence points are determined. The indicator has been found to be suitable in titrations of mixtures of manganese and zinc. 相似文献
55.
A rapid, sensitive and highly selective spectrophotometric method for the determination of manganese oxide content of Portland cement and cement raw meal is developed. The method is based on the reaction of manganese(II) with 1,2,4 trihydroxyanthraquinone (purpurin, PURP) in 50% v/v ethanol-water solution at pH 8.5. The solution equilibria of manganese chelates are demonstrated and characterized for delineating optimal conditions of the complexation reaction and analytical aspect of the Mn-PURP system. The analysis of cement materials of variable manganese content is feasible over the concentration range 1.67-8.13 microg ml(-1) Mn, the limit of detection (at the 95% confidence level) of the method is 68 ng ml(-1) for manganese. Under optimum conditions, the use of first derivative spectrophotometry has the advantage of high sensitivity than normal spectrophotometric method and allows the determination of 0.5 microg ml(-1) of manganese. 相似文献
56.
57.
Ahmed Galal Soher A. Darwish Rasha A. Ahmed 《Journal of Solid State Electrochemistry》2007,11(4):521-530
Conducting polymers were deposited on the surface of platinum and glassy carbon electrodes. The monomers used were N-methyl pyrrole and 3-methyl thiophene. The electrochemical synthesis of the polymer was achieved using constant applied potential
or cyclic polarization techniques in acetonitrile as a solvent and tetra-alkyl ammonium salts as supporting electrolyte. The
resulting conducting polymeric film was modified with an inorganic metal complex, namely, Cu–phthalocyanine or Co–phthalocyanine.
Two different approaches were adopted for the modification: (1) the first was to directly apply the metal–phthalocyanine layer
on the surface of the polymer, and (2) the second was by the inclusion of the metal–phthalocyanine in a sol–gel matrix that
was in turn applied to the conducting polymer film. In the first part of this work, we studied the effect of changing the
type of polymer matrix and the central metal of the inorganic complex on the electrochemical behavior of the resulting film.
We also found that changing the method of metal–phthalocyanine application to the polymer film affected the electrochemical
response and kinetics at the electrode surface. The new electrode was tested for the reduction of hydrogen peroxide and showed
better conversion efficiency compared to conventional surfaces, which suggests its use in fuel cell applications. 相似文献
58.
El-Ansari Mohamed A. Abdel-Latif Rasha R. Baczek Katarzyana Awad Hanem M. Sharaf Mohamed 《Chemistry of Natural Compounds》2022,58(3):433-437
Chemistry of Natural Compounds - From the methanolic extract of the flowers of Filipendula vulgaris, a new dimeric flavonol is isolated and identified as quercetinyl... 相似文献
59.
Alaa A. Hasseb Nourel din T. Abdel Ghani Ola R. Shehab Rasha M. El Nashar 《Current Opinion in Electrochemistry》2022
The determination of biomedical markers and pathogens using electrochemical sensors is a well-established technique in which the transducer and the recognition element are used to detect the target molecule. There is a growing interest in molecularly imprinted polymer (MIPs) applications as promising recognition elements. The use of MIPs as recognition elements in electrochemical sensors offers the advantages of being fast, low cost, and, at the same time, provides accurate and selective results compared with other commonly applied routine methods for biomedical markers and pathogen detection. Compared with other nanomaterials and aptamer-based biosensors, MIP-based sensors offered excellent selectivity for low-priced reagents to be used. The aim of the current review is to discuss the most recent applications of MIP-based electrochemical sensors (2019–2021) as promising detection devices for some important biomarkers, enzymes, and pathogens, such as viruses, bacteria, and toxins. 相似文献
60.
Mohammedi R. Abdel-Aziz 《Numerical Functional Analysis & Optimization》2013,34(3-4):319-336
An algorithm for solving the problem of minimizing a quadratic function subject to ellipsoidal constraints is introduced. This algorithm is based on the impHcitly restarted Lanczos method to construct a basis for the Krylov subspace in conjunction with a model trust region strategy to choose the step. The trial step is computed on the small dimensional subspace that lies inside the trust region. One of the main advantages of this algorithm is the way that the Krylov subspace is terminated. We introduce a terminationcondition that allows the gradient to be decreased on that subspace. A convergence theory for this algorithm is presented. It is shown that this algorithm is globally convergent and it shouldcope quite well with large scale minimization problems. This theory is sufficiently general that it holds for any algorithm that projects the problem on a lower dimensional subspace. 相似文献