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91.
Perpetua Wanjiru Muchiri M. Agouri Sahar Abdeen Mohamed A. Abbassi S. Taj B. Manaut Ashim Dutta Junaid Khan T. Mundad Youssef Bakkour Murefah mana Al-Anazy 《International journal of quantum chemistry》2024,124(7):e27368
This research work investigates the structural, electronic, optical, and thermoelectric characteristics of VFeZ (Z = N and P) half-Heusler compounds. The study employs the full-potential linearized augmented plane wave (FP-LAPW) method integrated into the WIEN2K algorithm, serving as the underpinning framework for density functional theory (DFT) analysis. In the study, we use the PBE generalized gradient approximation (PBE-GGA) to identify numerous parameters associated with structural and elastic properties. Lattice parameter results are in agreement with previous outcomes. Moreover, computed elastic parameters satisfy the criterion for stability. In the cubic structure VFeZ (Z = N and P) is ductile, to enhance the computations of electronic characteristics, Tran and Blaha's modified Becke-Johnson potential (TB-mBJ) is used. Our simulations demonstrate that the materials exhibit semiconductor behavior, with a direct band gap for VFeZ (Z = N and P). Strong UV absorption is found via optical experiments suggest compounds are suitable for optical application. Furthermore, study of the thermoelectric properties suggests its application in the thermoelectric generators. 相似文献
92.
93.
Bert J. Debusschere Youssef M. Marzouk Habib N. Najm Blane Rhoads Dimitris A. Goussis Mauro Valorani 《Combustion Theory and Modelling》2013,17(1):173-198
This paper presents a novel tabulation strategy for the adaptive numerical integration of chemical kinetics using the computational singular perturbation (CSP) method. The strategy stores and reuses CSP quantities required to filter out fast dissipative processes, resulting in a non-stiff chemical source term. In particular, non-parametric regression on low-dimensional slow invariant manifolds (SIMs) in the chemical state space is used to approximate the CSP vectors spanning the fast chemical subspace and the associated fast chemical time-scales. The relevant manifold and its dimension varies depending on the local number of exhausted modes at every location in the chemical state space. Multiple manifolds are therefore tabulated, corresponding to different numbers of exhausted modes (dimensions) and associated radical species. Non-parametric representations are inherently adaptive, and rely on efficient approximate-nearest-neighbor queries. As the CSP information is only a function of the non-radical species in the system and has relatively small gradients in the chemical state space, tabulation occurs in a lower-dimensional state space and at a relatively coarse level, thereby improving scalability to larger chemical mechanisms. The approach is demonstrated on the simulation of homogeneous constant pressure H2–air and CH4–air ignition, over a range of initial conditions. For CH4–air, results are shown that outperform direct implicit integration of the stiff chemical kinetics while maintaining good accuracy. 相似文献
94.
Electric transport in a Cu-doped Cd salt [(CH2)3(NH3)2Cd1? x Cu x Cl4, x?=?0.0, 0.07, 0.395 and 0.69] was investigated in the frequency range 60?Hz–100?kHz and the temperature range 290–450?K. The conductivity increases with increasing copper doping. Samples with x?=?0.0 and 0.07 undergo phase transitions at 374?K and 369?K, respectively. Ferroelectric relaxor-like behaviour appears for x?=?0.395 and 0.69. The conduction mechanism of the samples with x?=?0.0 and 0.07 depends on the temperature region. Below the transition temperatures chlorine vacancy and proton hopping prevails, whereas above the transition temperatures mainly proton conduction dominates. Transport in the new non-oxide ferroelectric relaxors, where x?=?0.395 and 0.69, can be explained by the jump relaxation model where proton and ionic hopping contribute to the conductivity throughout the whole temperature range. 相似文献
95.
Youssef Ait Ahmed Ahmed Tirbiyine Ahmed Taoufik Hassan El Ouaddi Habiba El Hamidi Abdelhalim Hafid 《Phase Transitions》2013,86(11):1093-1099
ABSTRACTWe have studied the reversible and irreversible part of the hysteresis loops as a function of slow cooling rate through the order–disorder transformation near 80?K for the deuterated (κ-D8-Br) κ-(BEDT-TTF)2Cu[N(CN)2]Br organic superconductor. We estimated the critical current density JC and the thermodynamic critical field HC from the magnetic hysteresis loops. Temperature dependence of the critical current density derived from the irreversible part using Bean’s model. The thermodynamic critical field HC has been obtained from the reversible part of the hysteresis loops. 相似文献
96.
Background
Several studies have shown that Stroop interference is stronger in children than in adults. However, in a standard Stroop paradigm, stimulus interference and response interference are confounded. The purpose of the present study was to determine whether interference at the stimulus level and the response level are subject to distinct maturational patterns across childhood. Three groups of children (6–7 year-olds, 8–9 year-olds, and 10–12 year-olds) and a group of adults performed a manual Color-Object Stroop designed to disentangle stimulus interference and response interference. This was accomplished by comparing three trial types. In congruent (C) trials there was no interference. In stimulus incongruent (SI) trials there was only stimulus interference. In response incongruent (RI) trials there was stimulus interference and response interference. Stimulus interference and response interference were measured by a comparison of SI with C, and RI with SI trials, respectively. Event-related potentials (ERPs) were measured to study the temporal dynamics of these processes of interference.Results
There was no behavioral evidence for stimulus interference in any of the groups, but in 6–7 year-old children ERPs in the SI condition in comparison with the C condition showed an occipital P1-reduction (80–140 ms) and a widely distributed amplitude enhancement of a negative component followed by an amplitude reduction of a positive component (400–560 ms). For response interference, all groups showed a comparable reaction time (RT) delay, but children made more errors than adults. ERPs in the RI condition in comparison with the SI condition showed an amplitude reduction of a positive component over lateral parietal (-occipital) sites in 10–12 year-olds and adults (300–540 ms), and a widely distributed amplitude enhancement of a positive component in all age groups (680–960 ms). The size of the enhancement correlated positively with the RT response interference effect.Conclusion
Although processes of stimulus interference control as measured with the color-object Stroop task seem to reach mature levels relatively early in childhood (6–7 years), development of response interference control appears to continue into late adolescence as 10–12 year-olds were still more susceptible to errors of response interference than adults. 相似文献97.
Antonia Youssef Anne von Koschembahr Sylvain Caillat Sebastien Corre Marie‐Dominique Galibert Thierry Douki 《Photochemistry and photobiology》2019,95(1):237-243
Exposure to solar UV is at the origin of numerous photodegradation pathways in biomolecules. Tryptophan is readily modified by UVB radiation into ring‐opened and oxidized photoproducts. One of them, 6‐formylindolo[3,2‐b]carbazole (FICZ), has been extensively studied in the recent years because it very efficiently binds to AhR, a major factor in numerous biologic processes, such as metabolism of xenobiotics. Unfortunately, little information is available on the actual yield of FICZ upon exposure to low and biologically relevant doses of UV radiation. In the present work, we used a sensitive and specific HPLC‐tandem mass spectrometry assay to quantify a series of photoproducts induced by UVB and simulated sunlight (SSL) in solutions of tryptophan. FICZ represented only a minute amount of the photoproducts (0.02 and 0.03%, respectively). Experiments were repeated in culture medium where the yield of FICZ was also found to be very low, even when Trp was added. Last, no FICZ could be detected in cytosolic fractions of cultured cells exposed to SSL. Altogether, the present results show that FICZ is a very minor photoproduct and that it cannot be considered the only endogenous photoproduct responsible for the induction of AhR‐dependent responses in UV‐irradiated cells. 相似文献
98.
M. Salou B. Lescop S. Rioual A. Lebon J. Ben Youssef B. Rouvellou 《Surface science》2008,602(17):2901-2906
X-ray photoelectron spectroscopy (XPS) and work-function measurements were used in combination to investigate the initial steps of Permalloy (Ni80Fe20) oxidation at room temperature. They showed that, after oxygen saturation, the surface is covered by nickel oxide (NiO), nickel hydroxide (Ni(OH)2) and iron oxides (FexOy), and there is no preferential oxidation. Iron oxidation proceeds through the formation of FeO (Fe2+) followed with Fe2O3 growth (Fe3+). The oxidation is governed by a dissociative Langmuir-type oxidation: the sticking coefficient is decreasing over oxygen exposure. Oxidation continues by oxygen dissolution into the first layers to form a nano-oxide of about 8 Å in thickness. 相似文献
99.
Dabaki Youssef Khaldi Chokri ElKedim Omar Fenineche Nouredine Lamloumi Jilani 《Journal of Solid State Electrochemistry》2022,26(2):457-468
Journal of Solid State Electrochemistry - In this paper, we study systematically the effect of ball/powder weight ratio on the morphological, structural, and electrochemical properties of... 相似文献
100.
Enrico Falcone Ikhlas M. M. Ahmed Dr. Valentina Oliveri Dr. Francesco Bellia Dr. Bertrand Vileno Dr. Youssef El Khoury Prof. Petra Hellwig Prof. Peter Faller Prof. Graziella Vecchio 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(8):1871-1879
Mounting evidence supports the role of amyloidogenesis, oxidative stress, and metal dyshomeostasis in the development of neurodegenerative disorders. Parkinson's Disease is characterized by α-synuclein (αSyn) accumulation and aggregation in brain regions, also promoted by Cu2+. αSyn is modified by reactive carbonyl species, including acrolein (ACR). Notwithstanding these findings, the interplay between ACR, copper, and αSyn has never been investigated. Therefore, we explored more thoroughly the effects of ACR on αSyn using an approach based on LC-MS/MS analysis. We also evaluated the influence of Cu2+ on the protein carbonylation and how the ACR modification impacts the Cu2+ binding and the production of Reactive Oxygen Species (ROS). Finally, we investigated the effects of ACR and Cu2+ ions on the αSyn aggregation by dynamic light scattering and fluorescence assays. Cu2+ regioselectively inhibits the modification of His50 by ACR, the carbonylation lowers the affinity of His50 for Cu2+ and ACR inhibits αSyn aggregation both in the presence and in the absence of Cu2+. 相似文献