检索结果-南通市图书馆

Theoretical prediction of structural,electronic and optical properties of quaternary alloy Zn_(1-x)Be_xS_ySe_(1-y)

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2012年第3期21卷 321-327页

作者： Hacini K Meradji H Ghemid S El Haj Hassan F laboratoire LPR D'epartement de PhysiqueFaculté des SciencesUniversité de Annaba laboratoire de physique des Matériaux Faculté des SciencesUniversité Libanaise

Within density functional theory based on the full potentiM-linearized augmented plane wave method, we carry out the first-principles calculation of the structural, electronic, and optical properties of the zinc blende quaternary alloy Zn1-xBexSySe1-y. The Perdew-Burke-Ernzerhof generaized gradient approximation based on the optimization of total energy and the Engel-Vosko generalized gradient approximation based on the optimization of the corresponding potential are used. Our investigation on the effect of the composition on lattice constants, bulk modulus, band gap, optical dielectric constant, and refractive index shows a non-linear dependence. The energy gap Eg（x, y） has been determined over the entire compositions x and y. In addition, the energy band gap of the technologically important quaternary alloy Znl-xBexSySe1-y in conditions of being lattice matched to ZnS substrate has been investigated. It is noteworthy that the present work is the first theoretical study of the quaternary alloy of interest.

关键词： density functional theory full potential-linearized augmented plane wave method qua-ternary alloy lattice-matched substrate

Surface morphology and electrochemical characterization of electrodeposited Ni-Mo nanocomposites as cathodes for hydrogen evolution

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2015年第10期24卷 559-563页

作者： Elhachmi Guettaf Temam Hachemi Ben Temam Said Benramache laboratoire de physique des Couches Minces et Applications Université de Biskra

In this work, we study the influences of current density on surface morphology and electrochemical characterization of electrodeposited Ni-Mo. The Ni-Mo composite coatings are deposited on pretreated copper substrates by electrolytic deposition. The Ni-Mo solution is taken from nickel sulfate fluid and ammonium heptamolybdate with 10 g/l. The Ni-Mo composite coatings are deposited at a temperature of 303 K with an applied current density of j dep= 10 A/dm2-30 A/*** find that the corrosion resistance is improved by incorporating Mo particles into Ni matrix in 0.6-M Na Cl solution. From the potentiodynamic polarization curve of electrodeposited Ni-Mo it is confirmed that the corrosion resistance decreases with increasing applied current density. The x-ray diffraction（XRD） analyses of Ni-Mo coatings indicate three phases of Mo Ni4, Mo1.24Ni0.76, and Ni3 Mo phases crystallites of nickel and molybdenum. The scanning electronic microscopy（SEM） tests indicate that Ni-Mo coatings present cracks and pores.

关键词： Ni-Mo electrolytic deposition corrosion resistance potentiodynamic polarization plating current density

Comparative Study of Entanglement and Wigner Function for Multi-Qubit GHZ-Squeezed State

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2017年第12期67卷 729-734页

作者： Fatima-Zahra Siyouri laboratoire de physique Thèorique Département de Physique Faculté des Sciences Université Mohammed Ⅴ-Agdal

In this paper we address the possibility of using the Wigner function to capture the quantum entanglement present in a multi-qubit system. For that purpose, we calculate both the degree of entanglement and the Wigner function for mixed tripartite squeezed states of Greenberger–Horne–Zeilinger(GHZ) type then we compare their behaviors. We show that the role of Wigner function in detecting and quantifying bipartite quantum correlation [Int. J. Mod. Phys. B30(2016) 1650187] may be generalized to the multipartite case.

关键词： negativity of Wigner function entanglement squeezed states tripartite GHZ non-classicality

Numerical Study of Natural Convection in an Inclined Porous Cavity

在线全文

学校读者我要写书评

暂无评论

Fluid Dynamics & Materials Processing 2022年第5期18卷 1389-1397页

作者： Saad Adjal Sabiha Aklouche-Benouaguef Belkacem Zeghmati laboratoire des Transports Polyphasiques et milieux Poreux LTPMPALGER16111ALGERIE laboratoire des Mathématiques et physique des Systèmes LAMPSPerpignan66860France

Two-dimensional transient laminar natural convection in a square cavity containing a porous medium and inclined at an angle of 30°is investigated *** vertical walls are differentially heated,and the horizontal walls are *** effect of Rayleigh number on heat transfer and on the road to chaos is *** natural heat transfer and the Darcy Brinkman equations are solved by using a finite volume method and a Tri Diagonal Matrix Algorithm(TDMA).The results are obtained for a porosity equal to 0.45,a Darcy number and a Prandtl respectively equal to 10^(-3)and 0.71;they are analyzed in terms of streamlines,isotherms,phase portrait,attractors,and spectra amplitude as a function of the Rayleigh *** is found that,as Rayleigh number increases,the natural convection changes from a steady state to a time-periodic state and finally to a chaotic condition.

关键词： Natural convection porous medium finite volumes chaos attractors

Auto-correlation Effects on the sp^3-d Exchange Interaction in Cd1-x MnxTe/CdTe Multilayers

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics Letters 2002年第11期19卷 1679-1682页

作者： K. Afif, A. Benyoussef and J. Diouri laboratoire de Magnetisme Faculte des Sciences Groupe d"Electronique et de physique du Solide Faculte des Sciences

Band offsets and total energy of Wannier excitons in multilayers are affected by dimensional and auto-correlation effects, and sp^3-d coupling is consequently modified. Thus, the calculation of the Zeeman splitting in the quantum wells has to take into account these effects, especially when the mismatch cannot be disregarded. In this work, the theoretical study of these combined effects has been performed for Cd1-xMnxTe/CdTe multilayers embedded by Cd1-yZnyTe as the substrate (or the buffer) on one side and as a cladding layer on the other side. This sample allows us to highlight the role played by the substrate (buffer) and the growth direction on the Zeeman splitting in such multilayers

关键词： Multilayers

Surface Effects on Wannier Excitons in Superlattices:Monte Carlo Simulation

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics Letters 2002年第8期19卷 1164-1167页

作者： K. Afif, A. Benyoussef and J. Diouri laboratoire de Magnetisme Faculte des Sciences Groupe d"Electronique et de physique du Solide Faculte des Science

Using a Monte Carlo quadrature, we calculate by a variational method the binding energy Eb of Wannier excitons in N-period m-CdMnTe/n-CdTe superlattices, including or not including the step discontinuity in the potential barrier at the interface, and with varying N as well as well width. The calculation is performed in the framework of the effective mass approximation for both heavy-hole and light-hole excitons. The degree of exciton localization dependence on these parameters is accurately illustrated.

关键词： Monte Carlo methods

Enhanced dielectric performance of Dy-substituted YMn2O5 for high-frequency applications

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2021年第5期31卷 762-771页

作者： H.Chouaibi K.Khirouni E.Dhahri laboratoire de physique Appliquée Faculté des Sciences Université de Sfax laboratoire de physique des Matériaux et des Nanomatériaux Appliquée à l'Environnement Faculté des Sciences de Gabès Cité Erriadh Université de Gabès

The dielectric performances as well as the effects of Dy3+ions content at A sites of YMn2O5(YMO) [x=0(YDM0)and x=0.4(YDM0.4)] polycrystalline samples were *** compounds were synthesized via sol-gel method.X-Ray diffraction and Raman measurements proved the high quality of the compounds that crystallized in an orthorhombic structure with the Pbam space ***,impedance spectroscopy and electrical modulus studies revealed that both samples exhibited a non-debye’s type of *** decrease of impedance for YDM0.4compared to the pure YDM0,may be attributed to the decrease in charge transfer *** the fit of impedance spectra,they confirmed that both compounds were simultaneously capacitive and ***,the activation energies obtained from Modulus and complex impedance were proven to be neighboring,suggesting that the relaxation process refers to electron *** each compound,the evolution of ε’and tan & with temperature indicated a clearer relaxor behavior,namely the existence of two *** first one detected at low temperature is related to the charge carriers hopping between Mn3+and Mn4+and the second at high temperature is associated with oxygen *** reduced hopping rate with Dy3+substitution for Y3+ions at A sites is responsible for the decrease in dielectric constant and dielectric *** significant findings demonstrate that these materials can be invested in a fruitful use in UV photo-detector and power applications in high frequency as microwave,millimeter wave signal processing,for civilian,military and space applications.

关键词： Multiferroic Relaxation phenomenon High dielectric constant Relaxor behavior

Pressure-broadened atomic Li(2s-2p) line perturbed by ground neon atoms in the spectral wings and core

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics B 2017年第7期26卷 67-74页

作者： Sabri Bouchoucha Kamel Alioua Moncef Bouledroua Physics department Badji Mokhtar University laboratoire de physique de la Matière et du Rayonnement Chérif Messaidia University laboratoire de physique des Rayonnements Badji Mokhtar University

Full quantum calculations are performed to investigate the broadening profiles of the atomic lithium Li（2s-2p） resonance line induced by interactions with ground Ne（2s^22p^6） perturbers in the spectral wings and core. The X^2Σ~＋, A^2Π,and B^2Σ~＋ potential-energy curves of the two first low lying Li Ne molecular states, as well as the corresponding transition dipole moments, are determined with ab initio methods based on the SA-CASSCF-MRCI calculations. The emission and absorption coefficients in the wavelength range 550-800 nm and the line-core width and shift are investigated theoretically for temperatures ranging from 130 K to 3000 K. Their temperature dependence is analyzed, and the obtained results are compared with the previous experimental measurements and theoretical works.

关键词： pressure broadening emission and absorption coefficients linewidth lineshift

Properties of n-type SnO_2 semiconductor prepared by spray ultrasonic technique for photovoltaic applications

在线全文

学校读者我要写书评

暂无评论

Journal of Semiconductors 2015年第12期36卷 34-37页

作者： H.Bendjedidi A.Attaf H.Saidi M.S.Aida S.Semmari A.Bouhdjar Y.Benkhetta laboratoire de physique des Couches Minces et Applications Université de Biskra laboratoire des Couches minces et Interfaces Université Mentouri

Transparent conducting n-type SnO2 semiconductor films were fabricated by employing an inexpensive, simplified spray ultrasonic technique using an ultrasonic generator at deferent substrate temperatures （300, 350, 400, 450 and 500 ℃）. The structural studies reveal that the SnO2 films are polycrystalline at 350,400, 450, 500 ℃ with preferential orientation along the （200） and （101） planes, and amorphous at 300 ℃. The crystallite size of the films was found to be in the range of 20.9-72.2 nm. The optical transmittance in the visible range and the optical band gap are 80% and 3.9 eV respectively. The films thicknesses were varied between 466 and 1840 nm. The resistivity was found between 1.6 and 4 × 10^-2 Ω.cm. This simplified ultrasonic spray technique may be considered as a promising alternative to a conventional spray for the massive production of economic SnO2 films for solar cells, sensors and opto-electronic applications.

关键词： tin oxide thin films spray ultrasonic structural properties optical properties