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排序方式: 共有198条查询结果,搜索用时 46 毫秒
21.
Zayed MA Mohamed GG Abdullah SA 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2011,78(3):1027-1036
Four novel azo compounds were synthesized; o-phenylazo- (C(14)H(13)N(3)O(2)) (I), p-bromo-o-phenylazo- (C(14)H(13)BrN(3)O(2)) (II), p-methoxy-o-phenaylazo- (C(15)H(16)N(3)O(3)) (III) and p-nitro-o-phenylazo-p-acetamidophenol (C(14)H(13)N(4)O(4)) (IV). These compounds were carefully investigated using elemental analyses, UV-vis, FT-IR, (1)H NMR and mass spectra. Also, the effects of p-substituents such as bromo, methoxy and nitro groups on the mass fragmentation pathways of these dyes were studied using Hammet's effects. This research aimed chiefly to threw lights on the structures-stability relationship of four novel newly prepared azo derivatives of p-acetoamidophenol. The data obtained referred to the variation of mass fragmentation pathways with the variation of p-substituent of these dyes which can be used in industry for various dyeing purposes. This variation is also correlated and verified by molecular orbital calculations which were done on ionic forms of these dyes using semi empirical PM3 program. The biological activities of these dyes were also investigated and its structure relationship was correlated. 相似文献
22.
M. A. Fahmey M. A. Zayed H. G. El-Shobaky 《Journal of Thermal Analysis and Calorimetry》2005,82(1):137-142
Summary This paper describes the use of the mass spectrometry (MS), thermal analyses (TA) and other physico-chemical methods to investigate
the structure of two newly synthesized phenolic-iodine derivative polymeric products. These two products are formed as a result
of redox-interaction of adrenaline hydrogen tartrate (AHT, I) with iodate (IO-3) and periodate (IO-4). The characterization of the two products were achieved satisfactorily by using the above tools and their proposed general
formulae, were found to be C52H67O36N4I (AHT- IO-3, II) and C26H34O18N2I2(AHT- IO-4, III). The fragmentation behavior of the main compound (AHT) in MS and TA (TG and DTA) techniques was investigated and compared.
The results obtained were used to explain the fragmentation of the products AHT- IO-3and AHT- IO-4in mass spectrometry and thermal analyses techniques. The stabilities of different fragments were discussed. The results indicate
that the two techniques are supporting each other in which the mass spectrometry provides the structural information in gas
phase while the thermal analyses provides the quantitative fragmentation in the solid-state. 相似文献
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24.
This paper applied the modified variational iteration method to the nonlinear coupled partial differential equations via the
generalized nonlinear Hirota Satsuma coupled KdV equations, the nonlinear coupled Kortewge–de Vries KdV equations and the
nonlinear shallow water equations together with the initial conditions. The proposed modification is made by introducing Adomian’s
polynomials in the correct functional. The suggested algorithm is quite efficient and is practically well suited for use in
such problems. The proposed iterative scheme finds the solution without any discritization, liberalization, perturbation,
or restrictive assumptions. 相似文献
25.
In this article, we have used the homotopy perturbation method (HPM) to find the travelling wave solutions for some non-linear initial-value problems in the mathematical physics. These problems consist of the Burgers–Fisher equation, the Kuramoto–Sivashinsky equation, the coupled Schordinger KdV equations and the long–short wave resonance equations together with initial conditions. The results of these problems reveal that the HPM is very powerful, effective, convenient and quite accurate to the systems of non-linear equations. It is predicted that this method can be found widely applicable in engineering and physics. 相似文献
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The present paper deal with the multi-component condensation of 8-hydroxy quinoline, aromatic aldehydes, and sulfone derivatives catalyzed by p-toluenesulfonic acid for the synthesis of a series of 4H-pyrano[3,2-h]quinoline derivatives in ethanol under ultrasonic irradiations. We provide a series of quinoline derivatives containing sulfone moiety interesting for biological screening tests. The reactions were carried out under both conventional and ultrasonic irradiation conditions. In general, improvement in rates and yields were observed when reactions were carried out under sonication compared with classical silent conditions. Also, also, sonochemical reaction give different reaction pathway other than silent reaction. These remarkable effects appeared in sonicated reactions can be reasonably interpreted in terms of acoustic cavitation phenomenon. Structures of the products were established on analytical and spectral data. 相似文献
29.
Zayed Elsayed M. E. Shohib Reham M. A. Alngar Mohamed E. M. Yıldırım Yakup 《Computational Mathematics and Modeling》2021,32(2):235-252
Computational Mathematics and Modeling - Based on the extended simplest equation method, we construct solitons and other solutions for the nonlinear convection-diffusion-reaction equation with... 相似文献