排序方式: 共有35条查询结果,搜索用时 15 毫秒
1.
Reda M. Fikry Nabila A. Ismael Adel A. El-Bahnasawy Aymen A. Sayed El-Ahl 《Phosphorus, sulfur, and silicon and the related elements》2013,188(6):1227-1236
Several new 2-arylidinoamino-4-(3-coumaryl)thiazole derivatives were synthesized via the reaction of 2-amino-4-(coumaryl)thiazole with aromatic aldehydes and other reagents. Structural elucidations were based on elementary analysis and spectral data studies. 相似文献
2.
Two synthetic protocols leading to novel γ-aminophosphonate and phosphine oxide derivatives, by reductive amination of γ-phosphonylketones, are reported. The first method involved a two-step procedure. Imine intermediates were first isolated from the p-toluenesulfonic acid-catalyzed reaction of primary amines with γ-ketophosphonates and phosphine oxides, then reduced with NaBH4 in refluxing ethanol. The second method consists of a one-pot procedure which includes the condensation of γ-ketophosphonates and phosphine oxides with primary amines, in the presence of molecular sieves, followed by reduction with NaBH4. These methods offer significant advantages over prior reports, such as efficiency, generality, and good yields. Furthermore, they are green protocols avoiding hazardous hydrides and solvents. 相似文献
3.
Mashhour Al-Ali Bani-Ata Christoph Hering Anni Neumann Aymen Rawashdeh 《Journal of Geometry》2007,86(1-2):1-5
The purpose of this paper is to prove the existence of semifields of order q
4 for any odd prime power q = pr, q > 3, admitting a free automorphism group isomorphic to Z
2 × Z
2. 相似文献
4.
Let ? n be the (2n + 1)-dimensional Heisenberg group, and let T n be the n-dimensional torus acting on ? n by automorphisms. In this paper, we describe the space of admissible coadjoint orbits of the Heisenberg motion group G n = T n ? ? n and we determine the topology of this space. We show that the bijection between the unitary dual ? n of G n and its admissible coadjoint orbit space is a homeomorphism. 相似文献
5.
In this research article, we work with the notion of the measures of noncompactness in order to establish some results concerning the essential pseudospectra of closed, densely defined linear operators in the Banach space. We start by giving a refinement of the definition of the essential pseudospectra by means of the measure of noncompactness, and we give sufficient conditions on the perturbed operator to have its invariance. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
6.
Periodica Mathematica Hungarica - In this paper, we define the localization operator associated with the Riemann–Liouville operator, and show that it is not only bounded, but it is also in... 相似文献
7.
Selective Detection of Dopamine in Presence of Ascorbic Acid by Use of Glassy‐Carbon Electrode Modified with Amino‐β‐Cyclodextrin and Carbon Nanotubes 下载免费PDF全文
Aymen Gaied Nejmeddine Jaballah Moncef Tounsi Mohamed Braiek Nicole Jaffrezic‐Renault Mustapha Majdoub 《Electroanalysis》2014,26(12):2747-2753
A glassy carbon electrode modified with per‐6‐amino‐β‐cyclodextrin (β‐CDNH2) and functionalized single‐walled carbon nanotubes (SWCNT‐COOH) was elaborated. This structure was investigated for the detection of dopamine acid (DA) in presence of ascorbic acid (AA). The sensor behavior was studied by cyclic voltammetry, square wave voltammetry and electrochemical impedance spectroscopy. The analysis results show that the electrode modification with CD derivative improves the sensitivity and selectivity of the DA recognition; the electrochemical response was further improved by introduction of SWCNT‐COOH. The sensor shows good and reversible linear response toward DA within the concentration range of 7×10?7–10?4 M with a detection limit of 5×10?7 M. 相似文献
8.
Aymen Bensouf Hichem Chtioui 《Calculus of Variations and Partial Differential Equations》2011,41(3-4):455-481
In this paper we prescribe a fourth order conformal invariant on the standard n-sphere, with n????5, and study the related fourth order elliptic equation. We prove new existence results based on a new type of Euler?CHopf type formula. Our argument gives an upper bound on the Morse index of the obtained solution. We also give a lower bound on the number of conformal metrics having the same Q-curvature. 相似文献
9.
Teresa Álvarez Aymen Ammar Aref Jeribi 《Mathematical Methods in the Applied Sciences》2014,37(5):620-644
In this paper, we investigate a detailed treatment of some subsets of essential spectra of a closed multivalued linear operator. On the following, we will establish some results on perturbation theory of 2 × 2 matrix of multivalued linear operators. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
10.
In the present paper, we define the S-left and the S-right essential spectra of a linear operator and we study the stability of the S-essential spectra on a Banach space. 相似文献