排序方式: 共有52条查询结果,搜索用时 31 毫秒
1.
Parasteh Pirasteh Ali Soltani Lazhar Haji Nicolas Errien 《Applied Surface Science》2006,253(4):1999-2002
In order to understand the optical loss mechanisms in porous silicon based waveguides, structural and optical studies have been performed. Scanning and transmission electron microscopic observations of porous silicon layers are obtained before and after an oxidation process at high temperature in wet O2. Pore size and shape of heavily p-type doped Si wafers are estimated and correlated to the optical properties of the material before and after oxidation. The refractive index was measured and compared to that determined by the Bruggeman model. 相似文献
2.
Farida Larit Khaled M. Elokely Manal A. Nael Samira Benyahia Francisco Len Stephen J. Cutler Mohammed M. Ghoneim 《Molecules (Basel, Switzerland)》2021,26(4)
The in vitro activity of L. donovani (promastigotes, axenic amastigotes and intracellular amastigotes in THP1 cells) and T. brucei, from the fractions obtained from the hydroalcoholic extract of the aerial part of Hypericum afrum and the isolated compounds, has been evaluated. The chloroform, ethyl acetate and n-butanol extracts showed significant antitrypanosomal activity towards T. brucei, with IC50 values of 12.35, 13.53 and 12.93 µg/mL and with IC90 values of 14.94, 19.31 and 18.67 µg/mL, respectively. The phytochemical investigation of the fractions led to the isolation and identification of quercetin (1), myricitrin (2), biapigenin (3), myricetin (4), hyperoside (5), myricetin-3-O-β-d-galactopyranoside (6) and myricetin-3’-O-β-d-glucopyranoside (7). Myricetin-3’-O-β-d-glucopyranoside (7) has been isolated for the first time from this genus. The chemical structures were elucidated by using comprehensive one- and two-dimensional nuclear magnetic resonance (1D and 2D NMR) spectroscopic data, as well as high-resolution electrospray ionization mass spectrometry (HR-ESI–MS). These compounds have also been evaluated for their antiprotozoal activity. Quercetin (1) and myricetin (4) showed noteworthy activity against T. brucei, with IC50 and IC90 values of 7.52 and 5.71 µM, and 9.76 and 7.97 µM, respectively. The T. brucei hexokinase (TbHK1) enzyme was further explored as a potential target of quercetin and myricetin, using molecular modeling studies. This proposed mechanism assists in the exploration of new candidates for novel antitrypanosomal drugs. 相似文献
3.
Labiadh Lazhar Barbucci Antonio Carpanese Maria Paola Gadri Abdellatif Ammar Salah Panizza Marco 《Journal of Solid State Electrochemistry》2017,21(8):2167-2175
Journal of Solid State Electrochemistry - In this paper, the electrocatalytic properties of PbO2 and TiRuSnO2 anodes for direct and indirect electrochemical oxidation of a synthetic solution... 相似文献
4.
We study q-Bessel negative definite functions and use their properties to give a proof of Lévy–Khintchine representation of q-infinitely divisible probability measures. 相似文献
5.
This paper deals with the diffusion approximation of a semiconductor Boltzmann–Poisson system. The statistics of collisions we are considering here, is the Fermi–Dirac operator with the Pauli exclusion term and without the detailed balance principle. Our study generalizes, the result of Goudon and Mellet [11], to the multi-dimensional case. 相似文献
6.
7.
S. Benalia M. Hachemaoui D. Rached R. Khenata N. Bettahar M. Benyahia 《Journal of Physics and Chemistry of Solids》2009,70(3-4):622-626
First-principles calculations have been used to investigate the structural, electronic and elastic properties of the filled skutterudite CeRu4P12, using the full-potential linear muffin-tin orbital (FP-LMTO) method. The exchange-correlation energy is described in the local spin density approximation (LSDA) using the Perdew–Wang parameterization. The results of the electronic properties show that this compound is an indirect band gap material. A special interest has been made to the determination of the elastic constants since there have been no available experimental and theoretical data. The energy band gaps and their volume and pressure dependence are investigated. Our results of the ground-state electronic properties are found to agree with experimental results. 相似文献
8.
Lazhar Bougoffa 《Applied Mathematics Letters》2009,22(8):1248-1251
In this paper, the solutions of initial value problems for a class of second-order linear differential equations are obtained in the exact form by writing the equations in the general operator form and finding an inverse differential operator for this general operator form. 相似文献
9.
Pouzot M Nicolai T Benyahia L Durand D 《Journal of colloid and interface science》2006,293(2):376-383
Non-linear mechanical behavior at large shear deformation was been investigated for heat-set beta-lactoglobulin gels at pH 7 and 0.1 M NaCl using both oscillatory shear and shear flow. These gels have a self-similar structure at length scales smaller than the correlation length of the gel with fractal dimension d(f)=2. Strain hardening is observed that can be well described using the model proposed by Gisler et al. [T.C. Gisler, R.C. Ball, D.A. Weitz, Phys. Rev. Let. 82 (1999) 1064] for fractal colloidal gels. The increase of the shear modulus normalized by the low strain value (G(0)) is independent of G(0). For weak gels the elasticity increases up to a factor of ten, while for strong gels the increase is very small. At higher deformation irreversible fracture occurs, which leads eventually to macroscopic failure of the gel. For weak gels formed at low concentrations the deformation at failure is about 2, independent of the shear modulus. For strong gels fracture occurs at approximately constant stress (2 x 10(3) Pa). 相似文献
10.
When high resolution convection schemes are used for discretizing chemical species mass balance equations, the mass fractions are not guaranteed to add to one. We show that a proposed remedy called χ —scheme (Darwish and Moukalled, Comput. Methods Appl. Mech. Engrg. 192 (2003): 1711) will degrade to a diffusive first‐order scheme when a chemical species vanishes from the mixture, for example, because of chemical reactions. We propose an improvement to the χ ‐scheme to overcome this problem. Furthermore, a computationally efficient alternative scheme is proposed and evaluated with several examples, to quantify the improvements in the accuracy and the computational time. Published 2013. This article is a U.S. Government work and is in the public domain in the USA. 相似文献