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排序方式: 共有195条查询结果,搜索用时 20 毫秒
91.
Bassam Mourad 《Linear and Multilinear Algebra》2004,52(2):99-113
In this article, we study generalized doubly stochastic matrices using the theory of Lie groups and Lie algebras. Applications to the inverse eigenvalue problem for symmetric doubly stochastic matrices are presented. 相似文献
92.
Bassam R. Fayad 《Bulletin of the Brazilian Mathematical Society》2000,31(3):277-285
We give an example of an analytic transformation onT
5 that conserves the Haar measure, that is minimal and topologically mixing, but is not ergodic. 相似文献
93.
Xavier Bantreil Nasreddine Kanfar Nicolas GehinEthan Golliard Pauline OhlmannJean Martinez Frédéric Lamaty 《Tetrahedron》2014
A convenient and user-friendly method to yield benzamides from primary and secondary amines and various benzylic alcohols in the presence of a cheap iron salt (FeCl2·4H2O) and tert-butylhydroperoxide (70% in water) as a stoichiometric oxidant is described. Control experiments indicated that this reaction might involve radical species. This method proved to be general, generating a family of 30 benzamides and was applied to the preparative synthesis of anti-anxiety drug moclobemide. 相似文献
94.
Nayer H. Sultana Stephen M. Kelly Bassam Mansoor Mary O'neill 《Liquid crystals》2007,34(11):1307-1316
We report the synthesis of oligophenylene polycatenar liquid crystals incorporating 1,4-disubstituted phenyl rings joined by a direct carbon carbon bond and some pyrimidine analogues. The nature of the linkages does appear to affect the mesomorphism significantly. The ratio of the aromatic core to the aliphatic chains is varied systematically by changing the number of 1,4-disubstituted phenyl rings and the length of the aliphatic chains. This strongly influences the transition temperatures of the mesophases. Some of the compounds are columnar over an extended temperature range of more than 200°C with melting points below room temperature. We suggest that a combination of the poor overlap of the conjugated electron system of the molecular cores making up the columnar structure and the high concentration of aliphatic chains leads to a low charge-carrier mobility. 相似文献
95.
96.
Tao Cai Jaap van de Beek Jad Nasreddine Marina Petrova Petri Mähönen 《International Journal of Wireless Information Networks》2011,18(3):131-145
In this article we describe a demonstrator that shows how the cognitive resource manager (CRM) and the radio-environmental
map (REM) can be efficiently implemented in full commercial grade cellular system (i.e., LTE system). The demonstrator shows
how the modular CRM together with its open interface, the universal link-layer API (ULLA), facilitates the implementation
of efficient radio resource management techniques guaranteeing the quality of service in the LTE system. The CRM, through
ULLA, is able to obtain PHY/MAC status information of the link between the tested eNode B and the user equipment, and reconfigure
link parameters. This measure-and-control by CRM/ULLA is independent of the underlying radio access technology, which shows
the neutrality of CRM/ULLA towards PHY/MAC characteristics. The article also shows how the REM can be easily implemented in
such system and how the REM provides the CRM with environmental information that enhances system management performance. 相似文献
97.
We analyze a problem which describes the frictional contact between a thermoviscoelastic body and a rigid foundation. The process is assumed to be quasistatic and the contact is modeled by a general normal damped response condition with friction law and heat exchange. Then we present a variational formulation of the problem, which is set in an abstract form as a system of evolution equations for the displacements and temperature. We establish the existence and uniqueness of the weak solution, using general results on evolution equations with monotone operators and fixed point arguments. Finally, we study the continuous dependence of the solution with respect to the initial data and contact conditions. 相似文献
98.
Rami K. Suleiman Wissam Iali Bassam El Ali Saviour A. Umoren 《Molecules (Basel, Switzerland)》2021,26(14)
The phytochemical analysis of the butanolic extract from the leaves of date palm of Saudi origin resulted in the isolation of three major constituents, oleanolic acid (1), vanillyl alcohol (2), and β-sitosterol-3-O-β-d-glucoside (3), which had not been isolated from this plant or previously reported. Together, compounds 1 and 2 account for 1.0% of the butanol extract, which represents 0.4% of the mass of the dried leaves. The isolation of other known compounds for this plant such as fatty acids, lutein, and sucrose was also achieved in this study. The characterization and identification of the isolated compounds were conducted on the basis of Fourier-transform infrared spectroscopy (FTIR), 1H and 13C nuclear magnetic resonance (NMR), liquid chromatography–mass spectrometry (LC–MS), and gas chromatography–mass spectrometry (GC–MS) analyses. The findings of the current study will definitely increase the knowledge about the contribution of the constituents of this plant to its well-known nutrition, corrosion inhibition, and antimicrobial properties. 相似文献
99.
Bassam Mourad 《Linear algebra and its applications》2012,436(9):3400-3412
In this note, we present a useful theorem concerning the spectral properties of doubly stochastic matrices. As applications, we use this result together with some known results that we recall, as a tool for extracting new sufficient conditions for the inverse eigenvalue problem for doubly stochastic matrices. 相似文献
100.
Prof. Bassam Alameddine Dr. Andrew H Rice Prof. Christine Luscombe Prof. Titus A Jenny 《ChemistryOpen》2015,4(4):453-456
We report the versatile synthesis of two tribenzo[fj,ij,rst]pentaphene (TBP) derivatives bearing two diarylamine substituents attached at the opposite ends of the aromatic core. Field effect transistor (FET) devices of the bis-diarylamine-TBP compounds were fabricated using spin coating under different concentrations, spin speed, and solvent conditions. Emission spectra and surface investigation by atomic force microscopy (AFM) reveal the formation of aggregates induced by the strong π–π stacking of the aromatic core leading to island features, and thus, unexpected low hole mobilities. The synthetic strategy we show herein, however, offers the possibility to decorate the TBP core structure with various charge-carrier peripheral groups and optimized alkyl chains, which should improve the crystalline property of their thin films upon deposition, leading consequently to a better hole transport mobility. 相似文献