排序方式: 共有71条查询结果,搜索用时 15 毫秒
41.
Aicha Bahnes Younes Mouchaal Fouad El Haj Hassan Zohra Bahnes Abdelkarim Bendoukha Reguig 《哲学杂志》2013,93(23):3000-3014
ABSTRACTThe spin-polarized structural, electronic and magnetic properties of the Ti-doped zincblende ZnS compound at x?=?0.50 (Zn0.50Ti0.50S alloy) have been investigated by employing the first-principles full-potential linearised augmented plane wave with local orbitals (FP-L/APW?+?lo) method within the frame-work of spin-polarized density functional theory (spin-DFT). For the treating of the structural properties, the electronic exchange and correlation (XC) functional was defined by generalised gradient approximation (GGA), whereas both GGA and GGA?+?U approximations are applied to treat and to compare the electronic and magnetic properties (U is the Coulomb repulsion energy). It has been confirmed that the ferromagnetic (FM) state of this alloy is found the most stable phase; however, all the equilibrium lattice parameters such as; lattice constant (a0), bulk modulus (B0), and its first-pressure derivative (B′) are computed in all paramagnetic, ferromagnetic and anti-ferromagnetic phases. The calculations of electronic properties unveil the perfect half-metallic character in the tetragonal Zn0.50Ti0.50S system. The computed magnetic properties reveal that the total magnetic moment is mainly originated from the transition element (TM) of Ti. Moreover, we have found that the p-d hybridisation is the paramount responsible for the reduction of the magnetic moment of TM from its free space charge value and for the production of minor magnetic moments on the nonmagnetic Zn and S sites. 相似文献
42.
In this paper, we consider the efficient estimation of local boiling heat fluxes from transient temperature measurements in
the heater close to the heater surface. For accurate prediction, heat flux estimation is formulated as a transient three-dimensional
(3D) inverse heat conduction problem (IHCP). This inverse problem is ill-posed and cannot be treated straightforwardly by
established numerical methods. In order to obtain a regularized stable solution, a large-scale time-dependent PDE-constrained
optimization problem has to be solved and an appropriate stopping criterion for the termination of the iterative solution
process has to be chosen. Since the boiling heat flux is non-uniformly distributed on the heater surface due to the strong
local activity of the boiling process, the use of a fixed uniform spatial discretization is not efficient. Instead, an adaptive
mesh refinement strategy can be used to obtain an appropriate discretization which significantly reduces the total computational
effort. In this work, we present an automatic algorithm incorporating an adaptive mesh refinement via a heat flux-based a-posteriori
error estimation technique. The suggested algorithm can cope with both spatially point-wise or highly resolved temperature
observations efficiently. It is applied to real measurement data obtained from two different types of pool boiling experiments.
The numerical results show that the computational effort can be reduced significantly for given estimation quality. This adaptive
IHCP solution technique can be also viewed as an efficient soft sensor to deduce unmeasurable local boiling heat fluxes. 相似文献
43.
Background
One mechanism that directs the action of the second messengers, cAMP and diacylglycerol, is the compartmentalization of protein kinase A (PKA) and protein kinase C (PKC). A-kinase anchoring proteins (AKAPs) can recruit both enzymes to specific subcellular locations via interactions with the various isoforms of each family of kinases. We found previously that a new class of AKAPs, dual-specific AKAPs, denoted D-AKAP1 and D-AKAP2, bind to RIα in addition to the RII subunits.Results
Immunohistochemistry and confocal microscopy were used here to determine that D-AKAP1 colocalizes with RIα at the postsynaptic membrane of the vertebrate neuromuscular junction (NMJ) and the adjacent muscle, but not in the presynaptic region. The labeling pattern for RIα and D-AKAP1 overlapped with mitochondrial staining in the muscle fibers, consistent with our previous work showing D-AKAP1 association with mitochondria in cultured cells. The immunoreactivity of D-AKAP2 was distinct from that of D-AKAP1. We also report here that even though the PKA type II subunits (RIIα and RIIβ) are localized at the NMJ, their patterns are distinctive and differ from the other R and D-AKAP patterns examined. PKCβ appeared to colocalize with the AKAP, gravin, at the postsynaptic membrane.Conclusions
The kinases and AKAPs investigated have distinct patterns of colocalization, which suggest a complex arrangement of signaling micro-environments. Because the labeling patterns for RIα and D-AKAP 1 are similar in the muscle fibers and at the postsynaptic membrane, it may be that this AKAP anchors RIα in these regions. Likewise, gravin may be an anchor of PKCβ at the NMJ. 相似文献44.
Aicha El Maadi Chance L. Matthiesen Philip Ershadi Jennifer Baker Derrick M. Herron Elizabeth M. Holt 《Journal of chemical crystallography》2003,33(10):757-763
The Knoevenagel reaction of benzaldehyde and several chloroderivatives with methyl cyanoacetate catalyzed by K2NiP2O7 leads to methyl (E)--cyanocinnamate derivatives in 40 min with yields of 71.65–83.45%. Pure products are easily obtained in crystalline form, uncontaminated by side products or by stereoisomers. Methyl 2-chlorocyanocinnamate, methyl 2,4-dichlorocyanocinnamate, and a new polymorph of methyl cyanocinnamate have been characterized by single crystal X-ray diffraction. 相似文献
45.
Dahane Soraya Gil García María Dolores Uclés Moreno Ana Martínez Galera María Socías Viciana María del Mar Derdour Aicha 《Mikrochimica acta》2015,182(1-2):95-103
Microchimica Acta - We describe a MWCNT-based method for the solid-phase extraction of eight pesticides from environmental water samples. The analytes are extracted from 100 mL samples at... 相似文献
46.
Samira Louhibi Aicha Yacouta Nour Laure Vendier Jean-Pierre Costes Jean-Pierre Tuchagues 《Polyhedron》2007
The synthesis and characterization of new dinuclear MnIII and tetranuclear CuII complexes, [HL1Mn(DMSO)]2 (1) and [H2L2Cu2(MeO)2]2 (2), are reported (H4L1 = 2-hydroxy-N-[2-({2-[(2-hydroxybenzoyl)amino]ethyl}amino)ethyl]benzamide and H4L2 = 2-hydroxy-N-[3-({3-[(2-hydroxybenzoyl)amino]propyl}(methyl)amino)propyl]benzamide). Single crystal X-ray structures have been determined for 1 and 2. In 1 only one of the two amide functions of H4L1 is deprotonated in addition to the phenol ones, while in 2 all the amide functions of H4L2 are protonated and none of the potential nitrogen donors (amide and amine) is involved in the coordination to copper. HL1 and H2L2 do not play the role of compartmental ligands and do not wrap around one Mn and one Cu ion, respectively, but embrace two metal centers yielding, with the respective assistance of auxiliary DMSO and methoxo ligands, dinuclear manganese and tetranuclear copper complexes, respectively. 1 includes two well isolated MnIII ions (Mn?Mn′ = 7.33 Å) that do not interact magnetically. The intermolecular Mn?Mn″ distance along the 1D chains (10.17 Å) is also too large to allow extended magnetic interactions. The pairwise magnetic interactions between the copper(II) ions in the tetranuclear complex 2 are so large that the χMT product is already equal to zero at room temperature, implying that the antiferromagnetic interaction is around −1000 cm−1, as observed previously for di-μ-hydroxo–dicopper complexes. 相似文献
47.
Hidden attractors in a new fractional–order discrete system: Chaos,complexity, entropy, and control
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This paper studies the dynamics of a new fractional-order discrete system based on the Caputo-like difference operator.This is the first study to explore a three-dimensional fractional-order discrete chaotic system without equilibrium. Through phase portrait, bifurcation diagrams, and largest Lyapunov exponents, it is shown that the proposed fractional-order discrete system exhibits a range of different dynamical behaviors. Also, different tests are used to confirm the existence of chaos,such as 0–1 test and C0 complexity. In addition, the quantification of the level of chaos in the new fractional-order discrete system is measured by the approximate entropy technique. Furthermore, based on the fractional linearization method, a one-dimensional controller to stabilize the new system is proposed. Numerical results are presented to validate the findings of the paper. 相似文献
48.
Abdelhakim Bouyahya Aicha El Allam Ikrame Zeouk Douae Taha Gokhan Zengin Bey Hing Goh Michelina Catauro Domenico Montesano Nasreddine El Omari 《Molecules (Basel, Switzerland)》2022,27(1)
Grifolin is a volatile compound contained in essential oils of several medicinal plants. Several studies show that this substance has been the subject of numerous pharmacological investigations, which have yielded interesting results. Grifolin demonstrated beneficial effects for health via its multiple pharmacological activities. It has anti-microbial properties against bacteria, fungi, and parasites. In addition, grifolin exhibited remarkable anti-cancer effects on different human cancer cells. The anticancer action of this molecule is related to its ability to act at cellular and molecular levels on different checkpoints controlling the signaling pathways of human cancer cell lines. Grifolin can induce apoptosis, cell cycle arrest, autophagy, and senescence in these cells. Despite its major pharmacological properties, grifolin has only been investigated in vitro and in vivo. Therefore, further investigations concerning pharmacodynamic and pharmacokinetic tests are required for any possible pharmaceutical application of this substance. Moreover, toxicological tests and other investigations involving humans as a study model are required to validate the safety and clinical applications of grifolin. 相似文献
49.
Jouini Houda Martinez-Ortigosa Joaquin Mejri Imène Mhamdi Mourad Blasco Teresa Delahay Gérard 《Research on Chemical Intermediates》2019,45(3):1057-1072
Research on Chemical Intermediates - The selective catalytic reduction of NO with ammonia (NH3-SCR) in the presence of H2O was studied over a series of Fe-Cu-ZSM-5 catalysts prepared by solid-state... 相似文献
50.
Khennaoui Amina Aicha Ouannas Adel Boulaaras Salah Pham Viet-Thanh Taher Azar Ahmad 《The European physical journal. Special topics》2020,229(6-7):1083-1093
The European Physical Journal Special Topics - This paper studies the dynamics of a new fractional-order map with no fixed points. Through phase plots, bifurcation diagrams, largest Lyapunov... 相似文献