排序方式: 共有92条查询结果,搜索用时 218 毫秒
41.
Mostefa Seghier Abdelghani Ouahab Johnny Henderson 《The European physical journal. Special topics》2017,226(16-18):3525-3549
In this work, we use a new random fixed point theorem in vector metric spaces due to Sinacer et al. [M.L. Sinacer et al., Random Oper. Stoch. Equ. 24, 93 (2016)] to prove the existence of solutions and the compactness of solution sets of a random system of fractional differential equations via the Hadamard-type derivative. The existence, modification and stochastically continuity of an M2-solution are also proved. 相似文献
42.
We announce the following result: every maximal globally hyperbolic 3-dimensional spacetime with compact Cauchy surface, and with nonpositive constant curvature admits a unique time function whose fibers are constant mean curvature surfaces. We discuss the extension of this result in higher dimensions. To cite this article: T. Barbot et al., C. R. Acad. Sci. Paris, Ser. I 336 (2003). 相似文献
43.
In the course of our investigations on halogen-free fire-retardant solutions for PMMA, the influence of oxide nanoparticles (TiO2, Al2O3) on the thermal stability and fire behaviour of PMMA blended with phosphinate additives (Exolit OP930 and OP1311) has been studied by thermogravimetric analysis and cone calorimetry. For each mixture, the residues obtained after combustion were examined and characterized by SEM, X-ray diffraction and X-ray microprobe analysis. Some synergistic effects were obtained between nanometric alumina and OP930 additive leading to the reduction of peak of heat released rate and of total heat released up to 30% and to the increase of time to ignition. From the results obtained, it can be proposed that OP930 and OP1311 act principally in the condensed phase, the presence of oxides playing a reinforcement role in the carbonaceous layer promoted by the phosphinate additives. 相似文献
44.
Labeled magnetic nanoparticles assembly on polypyrrole film for biosensor applications 总被引:1,自引:0,他引:1
In recent years, conducting polymers combined with metallic nanoparticles have been paid more attention due to their potential applications in microelectronics, microsystems, optical sensors and photoelectronic chemistry. The work presented in this paper describes the preparation and characterization of a nanocomposite composed by a thin polypyrrole (PPy) film covered with an assembly of magnetic nanoparticles (NPs). The magnetic particles were immobilized on PPy films under appropriate magnetic field in order to control their organization on the PPy film and finally to improve the sensitivity of the system in potential sensing applications. The electrical properties and morphology of the resulting PPy film and the PPy film/NPs composite were characterized with cyclic voltammetry, impedance spectroscopy (IS), scanning electron microscopy (SEM), atomic force microscopy (AFM) and infra-red spectroscopy (IR). By using streptavidin labeled magnetic particles it was possible to functionalize the NPs assembly with biotin-Fab fragment K47 antibody. The designed biosensor had been successfully applied in rapid, simple, and accurate measurements of atrazine concentrations, with a significantly low detection limit of 5 ng/ml. 相似文献
45.
Horacio J. Salavagione Diego Cazorla-Amors Selma Tidjane Mohammed Belbachir Abdelghani Benyoucef Emilia Moralln 《European Polymer Journal》2008,44(5):1275-1284
A detailed study about the synthesis, characterization and properties of poly(o-methylaniline)(PoMea)/maghnite nanocomposites has been performed. Changes in the characteristics of the nanocomposites, depending on the intercalated cation between the clay layers before the synthesis, have been observed. Intercalated morphology has been detected by TEM in nanocomposites containing copper-treated maghnite (Magh-Cu), while when maghnite treated with strong acids was used (Magh-H); an exfoliated material has been obtained. Also, remarkable differences in the properties of the polymers have been observed by TG-MS and FTIR, suggesting that the polymer produced with Magh-H has a higher degree of branching. The electrochemical behavior of the polymers extracted from the nanocomposites has been studied by cyclic voltammetry. Good electrochemical response has been observed for PoMea grown into Magh-Cu but not for the one polymerized into Magh-H. 相似文献
46.
Abdelghani OUAHAB 《数学学报(英文版)》2008,24(1):95-106
A recent nonlinear alternative for contraction maps in Frechet spaces due to Frigon and Granas (Resultats de type Leray-Schauder pour des contractions sur des espaces de Frechet, Ann. Sci. Math. Quebec 22, (2), 161-168 (1998)), combined with semigroup theory, is used to investigate the existence and uniqueness of mild solutions for first- and second-order functional semi linear and neutral damped differential equations in Frechet space. 相似文献
47.
Blandine Friederich Abdelghani Laachachi Michel Ferriol Marianne Cochez 《Polymer Degradation and Stability》2010,95(7):1183-24
Possible relationships between fire-retardant properties and thermal diffusivity for poly(methyl methacrylate) (PMMA) filled by melt blending with titanium dioxide (TiO2), alumina (Al2O3) and boehmite (AlOOH) were investigated for a better understanding of the mode of action of metal oxides as fire-retardants (FR) in PMMA. Fire-retardancy was measured with a cone calorimeter and thermal diffusivity (α) by Laser Flash Analysis (LFA). LFA measurements have shown that heat dispersion is higher with titanium dioxide and boehmite than with alumina despite a larger surface area. For thermal diffusivity, discrepancies between the different nanofillers were only visible from 10 wt% onwards. Thermal degradation of PMMA-oxide nanocomposites and their thermal diffusivity could be linked. Moreover, a bi-linear relationship between the peak of heat release rate (pHRR) and the average of heat release rate (AHRR) showed the occurrence of a barrier effect. 相似文献
48.
Consider a single server queueing system with several classes of customers, each having its own renewal input process and its own general service times distribution. Upon completing service, customers may leave, or re-enter the queue, possibly as customers of a different class. The server is operating under the egalitarian processor sharing discipline. Building on prior work by Gromoll et al.?(Ann. Appl. Probab. 12:797?C859, 2002) and Puha et al.?(Math. Oper. Res. 31(2):316?C350, 2006), we establish the convergence of a properly normalized state process to a fluid limit characterized by a system of algebraic and integral equations. We show the existence of a unique solution to this system of equations, both for a stable and an overloaded queue. We also describe the asymptotic behavior of the trajectories of the fluid limit. 相似文献
49.
Zhicheng Deng Hassen Bouchékif Keshwaree Babooram Abdelghani Housni Nankishoresing Choytun Ravin Narain 《Journal of polymer science. Part A, Polymer chemistry》2008,46(15):4984-4996
We report here a novel direct method for the syntheses of primary aminoalkyl methacrylamides that requires mild reagents and no protecting group chemistry. The reversible addition‐fragmentation chain transfer polymerization (RAFT) of the aminoalkyl methacrylamide revealed to be highly efficient with 4‐cyanopentanoic acid dithiobenzoate (CTP) as chain transfer agent and 4,4′‐azobis(4‐cyanovaleric acid) (ACVA) as initiator. Cationic amino‐based homopolymers of reasonably narrow polydispersities (Mw/Mn < 1.30) and predetermined molecular weights were obtained without recourse to any protecting group chemistry. A range of block and random copolymers were also synthesized via the RAFT process. The homopolymers and copolymers were characterized by aqueous conventional and triple detection gel permeation chromatography systems. Furthermore, the primary amine‐based methacrylamide monomers and polymers revealed to be highly stable both with the primary amino group in the protonated and deprotonated form. We have also demonstrated that stabilized gold nanoparticles can be generated with the RAFT‐synthesized amine‐based polymers via a photochemical process. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4984–4996, 2008 相似文献
50.
Ravin Narain Abdelghani Housni Lynsay Lane 《Journal of polymer science. Part A, Polymer chemistry》2006,44(22):6558-6568
We report here the successful functionalization of single‐walled carbon nanotubes with bioinspired sugar and phosphocholine polymeric structures via surface‐initiated atom transfer radical polymerization. The surface‐polymer‐coated carbon nanotubes have been systematically analyzed by Raman, infrared, ultraviolet–visible, and nuclear magnetic resonance spectroscopy and high‐resolution transmission electron microscopy, which give strong evidence of successful functionalization. The successful aqueous dispersion of the functionalized carbon nanotubes also indicates that functionalization has been achieved. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6558–6568, 2006 相似文献