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On Hawking Radiation of 3D Rotating Hairy Black Holes

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Chinese Physics Letters 2015年第10期32卷 14-16页

作者： Belhaj A Chabab M El Moumni H. Masmar K. SedraM. B. departement de physique Faculte Polydisciplinaire Universite Sultan Moulay Slimane Beni Mellal Morocco High Energy Physics and Astrophysics Laboratory FSSM Cadi A yyad University Marrakesh Morocco Ddpartement de physique LHESIR Faeulte des Sciences Universitd Ibn Tofail Kdnitra Morocco

We study the Hawking radiation of 3D rotating hairy black holes. Specifically, we compute the transition probability of bosonic and fermionic particles in such backgrounds. Then, we show that the transition probability is independent of the nature of the particle. It is observed that the charge of the scalar hairy B and the rotation parameter a control such a probability.

关键词： exp On Hawking Radiation of 3D Rotating Hairy Black Holes

HALOMETHYLATION OF POLYSTYRENE AND SUBSEQUENT PYRIDINATION VIA A HOMOLYTIC PATHWAY

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Chinese Journal of Polymer Science 2006年第6期24卷 627-635页

作者： Sad Moulay Nadia Mehdi Laboratoire de Chimie-physique Moléculaire et Macromoléculaire Faculté des Sciences de l'Ingénieur Departement de Chimie IndustrielleUniversité de BlidaRoute de SoumaB. P. 270Blida 09000Algeria

Chloromethylation of polystyrene （PS） with two different chloromethylating systems methylal/thionyl chloride and paraformaldehyde/trimethylchlorosilane was studied. Soluble chloromethylated polystyrene with a degree of substitution of 89% was obtained. The Conant-Finkelstein reaction on the chloromethylated PS afforded soluble iodomethylated polystyrene with a degree of substitution as high as 96%. The reaction conditions of Minisci were employed to radically pyridinate PS via its iodomethylated derivative. Polyelectrolytes were formed which could be converted to normal polymers by treatment with a 20% aqueous solution of NaOH.

关键词： Chloromethylated polystyrene Conditions of Minisci Iodomethylated polystyrene Pyridinated polystyrene.

Influences of nanoparticles and chain length on thermodynamic and electrical behavior of fluorine liquid crystals

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Chinese Physics B 2022年第10期31卷 410-416页

作者： Ines Ben Amor Lotfi Saadaoui Abdulaziz N.Alharbi Talal M.Althagafi Taoufik Soltani Université Tunis El Manar Laboratoire de Physique de la Matiére Molle et de la Modélisation Electromagnétique2092 Tunis Physics department College of ScienceTaif UniversityP.O.Box 11099Taif 21944Saudi Arabia

Hydrogen-bonded polar nematic liquid crystal series with the general formula n OBAF(n = 7-12) is studied. The mesomorphic characterization is demonstrated through differential scanning calorimetry(DSC) and polarized optical microscopy(POM). The complexes with short alkyl chains(n = 7, 8) present a wide nematic range and monotropic smectic F mesophase, whereas the longer alkyl chain(n = 10-12) analogues show high melting and low clearing mesomorphic liquid crystals. The thermal range of the mesophase and the birefringence increase with chain length decreasing. Furthermore, the effect of the nanoparticles(LiNbO_(3)) on the thermal and the electrical behavior of 8OBAF are investigated. The presence of LiNbO_(3) nanoparticles increases the conductivity and reduces the resistivity of the complex.

关键词： fluorine liquid crystal polar nematic ferroelectric nanoparticles thermal stability dielectric behavior

Effect of excitation wavelength(blue vs near UV)and dopant concentrations on afterglow and fast decay of persistent phosphor SrAl_(2)O_(4):Eu^(2+),Dy^(3+)

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Journal of Rare Earths 2022年第7期40卷 1022-1028页

作者： Bernhard Walfort Nando Gartmann Jafar Afshani Arnulf Rosspeintner Hans Hagemann LumiNova AG SwitzerlandSpeicherstrasse 60aCH-9053TeufenSwitzerland Dépt.de Chimie physique Universitéde Genève30Quai E.AnsermetCH 1211Geneva 4Switzerland

The persistent phosphor SrAl_(2)O_(4):Eu^(2+),Dy^(3+)is the subject of numerous *** often neglected aspect is that in this phosphor,as well as in Sr_(4)Al_(14)O_(25):Eu^(2+),Dy^(3+),there are two different Sr^(2)+sites which can be occupied by the dopant Eu^(2+)ions,We first introduce a general scheme of possible energy transfers in these persistent phosphor materials including explicitly both europium ions,This scheme is used as a generic starting point to study experimentally specific *** illustrate this application with the study of the effect of excitation wavelength(444 and 382 nm)on the afterglow of differently doped SrAl_(2)O_(4):Eu^(2+),Dy^(3+)samples,as well as on the emission decay *** the same excitation intensity under 444 nm excitation,the resulting afterglow intensity is stronger than under near UV *** 382 nm,Eu^(2+)ions on both Sr^(2)+s ites in SrAl_(2)O_(4)are excited,but at room temperature the blue emission is quenched,leading to a loss of *** observed effects can further be associated with the ratio of Eu^(2+)ions and trap states which are modulated by the concentrations of Eu^(2+)and Dy^(3+)in SrAl_(2)O_(4),as well as by temperature,Increasing the nominal Dy^(3+)content from 0.1 mol%to 0.5 mol%with respect to Sr results in the doubling of the integrated afterglow intensity and confirms thus that Dy^(3+)ions are indeed involved in the trapping process,The concentration of trap states is much lower than the concentration of Eu^(2+)ions,as even with low excitation densities,a plateau of integrated afterglow intensity(corresponding to the total number of accessible traps)is *** postulate that an important fraction of excited Eu^(2+)ions can potentially transfer their energy to trap *** that all traps are filled or in a dynamical filling-depletion process under illumination(with thermal and/or optical depletion processes),for the remaining Eu^(2+)a"normal"steady-state emission is observed

关键词： Persistent phosphor Strontium aluminate Europium Forster energy transfer Rare earths

Extraordinary piezoelectric effect induced in two-dimensional rare earth monochalcogenides via reducing system dimensionality

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Journal of Materiomics 2023年第1期9卷 72-81页

作者： Neveen I.Atallah Maged El-Kemary Fabien Pascale Khaled E.El-Kelany Institute of Nanoscience and Nanotechnology Kafrelsheikh University33516Kafr el-skiekhEgypt Universite de Lorraine-Nancy CNRSLaboratoire de Physique et Chimie TheoriquesUMR 7019Vandoeuvre-les-NancyFrance

Piezoelectricity is pivotal for applications in micro/nanoelectromechanical systems(MEMS/NEMS).Inducing such a property in 2D systems via the reduction of the dimensionality of their corresponding 3D bulk is here *** on DFT theory and Gaussian-type-localized basis sets,the structural,electronic,mechanical,and piezoelectric properties of both 3D and 2D rare earth monochalcogenides RmX(Rm=Tm,Yb,Lu,and X=S,Se,Te)are investigated using the CRYSTAL *** intriguingly,the 2D LuX compounds display a buckled structure,where the Lu and X atoms protrude from the monolayer surface leading to an additional out-of-plane piezoelectric effect;(e_(31)=2104.84,1770.28,1689.79 pC/m,and d31=56.37,49.76,and 147.90 pm/V for LuS,LuSe,and LuTe,respectively).Such piezoelectric response is two orders of magnitude larger than the one of recently reported 2D ferroelectric MXenes,and is nearly thirty times larger than the commonly used AlN and GaN bulk ***,the reduced elastic constants obtained,when compared to other 2D materials,confirm the flexibility and softness of the considered 2D systems.

关键词： 2D materials Rare earth monochalcogenides DFT Gaussian basis CRYSTAL code Piezoelectric effect MEMS/NEMS

Spatiotemporally reconfigurable light in degenerate laser cavities

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Photonics Research 2023年第10期11卷 1751-1756页

作者： A.BARTOLO N.VIGNE M.MARCONI G.BEAUDOIN L.LE GRATIET K.PANTZAS I.SAGNES A.GARNACHE M.GIUDICI UniversitéCôte d’Azur CNRSInstitut de Physique de Nice06200 NiceFrance Institut d’Electronique et des Systèmes CNRS UMR521434000 MontpellierFrance Centre de Nanosciences et de Nanotechnologies CNRS UMR 9001UniversitéParis-Saclay91120 PalaiseauFrance

We show that a Ⅲ-V semiconductor vertical external-cavity surface-emitting laser(VECSEL) can be engineered to generate light with a customizable spatiotemporal structure. Temporal control is achieved through the emission of temporal localized structures(TLSs), a particular mode-locking regime that allows individual addressing of the pulses traveling back and forth in the cavity. The spatial profile control relies on a degenerate external cavity, and it is implemented due to an absorptive mask deposited onto the gain mirror that limits the positive net gain within two circular spots in the transverse section of the VECSEL. We show that each spot emits spatially uncorrelated TLSs. Hence, the spatiotemporal structure of the light emitted can be shaped by individually addressing the pulses emitted by each spot. Because the maximum number of pulses circulating in the cavity and the number of positive net-gain spots in the VECSEL can be increased straightforwardly, this result is a proof of concept of a laser platform capable of handling light states of scalable complexity. We discuss applications to three-dimensional alloptical buffers and to multiplexing of frequency combs that share the same laser cavity.

关键词： light cavity mirror

Performance Analysis of a Radial N+/P Silicon Solar Cell in Steady State and Monochromatic Illumination

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Advances in Materials Physics and Chemistry 2023年第12期13卷 207-217页

作者： Aboubacar Savadogo Bernard Zouma Bruno Korgo Ramatou Konaté Sie Kam departement de physique Laboratoire d’Energies Thermiques Renouvelables Unité de Formation et de Recherche en Sciences exactes et appliquées Université Joseph KI-ZERBO Ouagadougou Burkina Faso

In this paper, we investigate theoretically a radial n+/p silicon solar cell in steady state and monochromatic illumination. The purpose of this work is to analyze the effect of the cell base radius on its electrical parameters. The continuity equation in cylindrical coordinates is established and solved based on Bessel functions and boundaries conditions;this led us to the photovoltage and photocurrent density in the cell. The open circuit voltage and the short circuit current density are then deduced and analyzed considering the base radius. Based on J-V and P-V curves, series and shunt resistances, fill factor and maximum power point are derived and the conversion efficiency of the cell is deduced. We showed that short circuit current density, maximum power, conversion efficiency and shunt resistance decrease with increasing base radius contrary to the open circuit voltage, the fill factor and the series resistance.

关键词： Solar Cell Radial Junction Shunt and Series Resistances Conversion Efficiency

Heavy Quarks Production in Hadronic Processes: Qualitative Study of Higher-Order Fock States

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Communications in Theoretical Physics 2009年第4期51卷 717-722页

作者： N.Mebarki K.Benhizia Z.Belghobsi D.Bouaziz Laboratoire de physique Mathematique et Subatomique Mentouri University Département de physique Universitéde Jijel

为在质子介子和光子介子碰撞的重夸克的生产的二个粒子 Fock 状态的贡献被学习。效果强烈取决于因式分解规模的生产重夸克团，和选择，这被显示出。

关键词： Fock态生产过程重夸克高阶强子制作质量分解尺度介子

Structure, Thermal Behavior and Characterization of a New Hybrid Iron Fluoride FeF4（2,2′-bipyridine）（H2O）2

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Chemical Research in Chinese Universities 2015年第1期31卷 16-20页

作者： Mouna SMIDA Hager LITAIEM Mohamed DAMMAK Santiago GARCIA-GRANDA Laboratoire de Chimie Inorganique Faculte des Sciences de Sfax Universite de Sfax 3000Sfax Tunisie departement de Chimie Physique Analytique Faculte de Chimie Universite d'Oviedo-CINN 33006 Oviedo Spain

New crystal of FeF4（2,2′-bipyridine）（H2O）2 was prepared by hydrothermal synthesis. Crystalline structure determination is performed from single crystal X-ray diffraction data. The unit cell is monoclinic space group P21/n, with cell parameters a=0.9046（5） nm, b=0.7502（5） nm, c=1.9539（5） nm,β=93.307（5）°, V=1.3238（12） nm^3 and Z=4. The structure of FeF4（2,2＇-bipyridine）（H2O）2 is built up from FeF4N2 octahedra coordinated by two nitrogen atoms of the 2,2＇-bipyridine molecules, and four fluorine atoms as well as uncoordinated H2O molecules. Thermal analysis of the title compound showed that the decomposition introduced four steps. IR spectra confirmed the presence of 2,2＇-bipyridine molecules. The optical absorption was measured at the corresponding 2max using UV-Vis diffuse reflectance spectrum.

关键词： Hydrothermal synthesis Hybrid Iron fluoride