01.Séminaire National Sur Laser Solaire Et Matériaux ElOeued 5-6 Février 2018

Permanent URI for this collectionhttps://dspace.univ-eloued.dz/handle/123456789/2330

Browse

Now showing 1 - 20 of 47

O+6, C+ حساب المقاطع الفعالة لعملية التأين بالتصادم الإلكتروني للبلازما المنتجة من طرف الليزر تطبيق على بلازما الهليون وايونات
(University of Eloued جامعة الوادي, 2018-02-05) حريز بلقاسم, منال; قدة, الحبيب
في بداية الستينات اهتم العديد من الباحثين والعلماء في فيزياء البلازما على دراسة التفاعل بين الليزر والمادة، إذ وجد أن هذا التفاعل يؤدي إلى إنتاج بلازما. وتعد الآليات الذرية الأساسية مهمة في معالجة انبعاثات و تشخيص البلازما، ومن أهمها عملية التأين بالتصادم الالكتروني. حيث أردنا من خلال هذا العمل التحكم في حساب المقاطع الفعالة لهذه العملية 1[. حيث يعتمد [ FAC وذلك باختيار برنامج ، C+4, O+ لبعض أنواع البلازما منها: بلازما الهليوم والشبيه بالهليوم منها 6 على هذا الأخير في حساب المقاطع الفعالة التي من خلالها نقوم كذلك باستنتاج معدل التأين بالتصادم الإلكتروني. حيث في مختلف المجالات الطاقوية C+4, O+ بينت النتائج المتحصل عليها للمقاطع الفعالة لبلازما الهيليوم والشبيه بالهليوم منها 6 .] توافقا مقبولا] 2 Tawara and Kato لإلكترونات الصدم مقارنة بالنتائج المتحصل عليها من طرف
Thermal conductivity between the flash laser and the thermic method
(University of Eloued جامعة الوادي, 2018-02-05) Khechekhouche, Abderrahmane; Attia, Mohamed El hadi; Benhissen, Nacer Eddine
The flash laser method was proposed by Parker Butler in 1961. It is the most popular method for measuring the thermal diffusivity of solids or Thermal conductivity. The thermal conductivity (λ) is a characteristic of each material. It is expressed in W/mK and it is only valid for homogeneous materials. There are several methods for measuring this coefficient. The ratio between a temperature difference and the resulting thermal flux density, i.e., thermal resistance, can be determined in any case correctly, irrespective of the mechanism of heat transfer through it. The best measurement accuracies (better than 1%) are obtained by the method of the hot plate kept. In the simpler case where the heat transfer is reduced to a single mode, that of conduction (steady state). The λ of the test piece can be calculated if its geometry and temperature differences are known. In this work we will quote and compare the Flash Laser method and the thermal method.
THE Z-SCAN TECHNIQUE TO CHARACTERIZE NON LINEAR OPTICAL MATERIALS: MODELING AND EXPERIMENT
(University of Eloued جامعة الوادي, 2018-02-05) TRAICHE, M.
I treat the Z-scan technique applied to characterize a non linear material, probed by a laser beam on one of its atomic transitions. By assuming the caustic of the probing optical beam in accordance with the geometric optics approximation, I model the Z-scan setup. I describe a Zscan experiment I performed in CDTA on a ruby crystal sample with a top hat laser beam from a Nd:YAG laser followed by a second harmonic generator. The experimental and theoretical Z-scan curves, thus obtained, show good agreement. The cubic non linearity in the material sample, ruby, is eventually determined.
SYSTEME LASER SOLAIRE FONCTIONNE EN MONOMODE ET MULTIMODE POMPE PAR DIFFERENTS FORME DE GUIDES DE LUMIERE EN SILICE FONDUE
(University of Eloued جامعة الوادي, 2018-02-05) Bouadjemine, R.; Liang, D.; Almeida, J.; Louhibi, D.; Kellou, A.
Notre travail consiste à optimiser les différents paramètres de pompage d’un système laser solaire, en utilisant une technique de calcul numérique dit « Ray-tracing » à l’aide du logiciel ZEMAX. Il a aussi pour objectif d’optimiser les paramètres du résonateur optique afin d’obtenir un rendement laser maximum en régimes multimodes et monomode TEM00, en utilisant le logiciel LASCAD. Ce système laser est constitué d’un système de collection et de concentration des rayonnements solaires grâce à un héliostat-miroir parabolique, d’un guide de lumière en silice fondue, d’une tête laser constituée d’une cavité de pompage de différentes formes assurant un bon couplage des rayonnements solaires vers le barreau laser Nd :YAG, et d’un système de refroidissement
SYNTHESIS, CHARACTERIZATION OF NEW HYBRID MATERIAL BASED ON POLYPYRROLE-TETRATHIAFULVALENE AND ZINC OXIDE
(University of Eloued جامعة الوادي, 2018-02-05) Tiaouinine, Siham; Kaboub, Lakhemici; Hamza, Djamel-Eddine; Azizi, Amor; Gouasmia, AK.
Her we report a preliminary study of material witch an organic material is combined with an inorganic material to yield a solar cell. ZnO was deposited electrochemically onto glass/ITO form aqueous solutions containing KNO3 and Zn (NO3)2. New molecule TTF donor (TTF: tetrathiafulvalene) containing pyrrole has been synthesized and its electron-donating ability determined by cyclic voltammetry. Then, Polypyrrole -TTF films have been grown on ZnO substrates from an acetonitrile solution of TBAPF6 - by the electropolymerisation technique. The chemical composition of the ZnO/Polypyroole-TTF films was determined by UV and IR spectroscopy. The morphology of the prepared film layers were detrmined using the AFM technique. Lastly, the band gap of the heterojunction, between the HOMO of the donor material Polypyrrole-TTF and the LUMO of the of the acceptor layer (ZnO) were estimated by UV-vis absorption spectra. This study shows a decrease in the gap energy value from 3.88 to 3.55 eV proved the interaction between the hybridbilayer
Study of Zn-Ni Alloy Coatings Modified by Nano-Al2O3 Particles Incorporation
(University of Eloued جامعة الوادي, 2018-02-05) Diafi, Malika; Temam, Elhachmi Guettaf; Gasmi, Brahim; Benramache, Said; Adaika, Mohamed Lakhdar
The aim of this research work was to codeposit nano-Al2O3 particles into Zn-Ni alloy coatings in order to improve some surface ,properties, the influence of the concentration of Al2O3 is the principal object in order to improve the corrosion resistance of the deposit, which has been made by electroplating on steel substrates previously treated, have been studied by several characterization methods, as the X-ray diffraction, measurement of micro hardness and scanning electron microscopy (SEM), protection against corrosion properties studied in a solution of 3% NaCl in the potentiodynamic polarization measurements (Tafel), electrochemical impedance spectroscopy (EIS) to the potential of corrosion free. The parameters that characterize the corrosion behavior can be determined from the plots and Nyquist plots and chronopotentiometry. Trends of increasing the charge transfer resistance and the decrease of capacitance values. XRD and SEM results and identify any coatings Zn- Ni and Zn-Ni-Al2O3 alloy composition have similar phase ( γ-phase structure) and the addition of Al2O3 in the Zn-Ni matrix increases the microhardness, and we note the maximum hardness is obtained for 50 g/L Al2O3.
STUDY OF PHASE TRANSFORMATIONS OF A SYNTHESIZED MULLITE
(University of Eloued جامعة الوادي, 2018-02-05) Chargui, F.; Hamidouche, M.
The use of ceramics as substrates for photovoltaic cells lends itself well to the various thin film deposition techniques. The mullite Al2O3-2SiO2 is a very good material for this application. It can be synthesized by different methods. The best indicated way is to enrich kaolin with alumina. In this work we studied the different transformations of phase of kaolin and kaolin- aluminum slag mixtures are studied. The raw materials used are local (from Algeria).During heat treatment, the kaolin- aluminum slag mixture undergoes several transformations of phase leading to the formation of mullite. The beginning of crystallization of the primary mullite is at 1000 ° C .The firing of the kaolin at 1400 °C led to the formation of the larger quantity of mullite but for the mixture led to the acceleration of the formation of secondary mullite. At 1500 ° C, the mullitization of the mixture is almost complete
STRUCTURAL, OPTICAL AND ELECTRICAL PROPERTIES OF BULK CuIn0.7Ga0.3Se2 SEMICONDUCTOR COMPOUND
(University of Eloued جامعة الوادي, 2018-02-05) Gagui, S.; Hadjoudja, B.; Chouial, B.; Zaidi, B.; Chibani, A.
In this work, we report on the study of structural, electrical and optical properties of the CuIn0.7Ga0.3Se2 compound. Analysis by X-ray diffraction showed that the prepared ingots are polycrystalline and of chalcopyrite structure. The preferential orientation in the plane (112) which is very suitable for the photovoltaic conversion was obtained. On the other hand, the lattice parameters a and c were calculated from the X-ray spectra, the c/a ratio was found to be equal to 2. Measurements of the electrical properties permitted us to get 7,645 Ω cm for the resistivity and 4,761.1016 cm-3 for the carrier concentration. Characterization by energy dispersive spectrometer (EDS) of the prepared ingots, allowed us to infer that their chemical composition is quasi-stoichiometric. Absorption measurements were performed using a UVVIS- NIR spectrophotometer and a value of 1.13 eV for the band gap width was obtained
STRUCTURAL, ELECTRICAL AND OPTICAL PROPERTIES OF IRON DOPED NiO NANOSTRUCTURE THIN LAYERS
(University of Eloued جامعة الوادي, 2018-02-05) Ghougali, M.; Belahssen, O.; Dogga, A.; Aoun, Y.
In this paper we studyed the structural, electrical and optical properties of the pure and iron doped thin layers of nickel oxide prepared at the molar concentration 0.1 mol/L of the nickel nitrate solution (Ni(NO3)2.6H2O) and Iron nitrate solution (FeN3O9.9H2O), thin layers of nickel oxide deposited on glass substrates under the temperature (500oC) by the pyrolytic spray technique. The diffraction results of the X-rays showed that the film layers prepared had a fcc structure and a ominant direction (111). It was noted that there was an increase in light transmission due to doping. Is reached (85%), On the other hand, the results of tests (FTIR) showed the emergence of chemical bonds (Ni-O) and (Fe-O), which appear in the wavenumber range (505-428.2 cm-1), The samples showed a remarkable decrease in electric conductivity after doping. the values of the optical band gap changed between (3.724) and (3.419 eV).
Spectroscopie des céramiques pour l’amélioration du rendement des cellules photovoltaïques
(University of Eloued جامعة الوادي, 2018-02-05) Bensalem, C.; Boulma, E.; Diaf, M.; Khiari, S.
This optical investigation of glass-ceramics formed by annealing glasses with compositions 50 GeO2 - 40 PbO - 10 PbF2 - x EuF3, x = [0.5; 1; 1.5; 2] and polycrystalline ceramics with composition 100 PbF2, y EuF3, with y = 5, 10, 15 and 20. For each material, the photoluminescence spectrum and the photoluminescence lifetimes of the 5D0, 5D1 and 5D2 Eu3+ levels are measured. Occurrence of β-PbF2: Eu3+ nanocrystallites in the glass-ceramics is confirmed and total ceramisation requires more than 10 % of EuF3 with respect to PbF2 in the starting glass. In the β-PbF2: Eu3+ ceramics and glass-ceramics, Eu3+ ions replace Pb2+ in their regular cubic site, but they interact together to form dimmers and higher nuclearity clusters. For the EuF3 rates investigated here, there are no isolated Eu3+ ions in the PbF2 lattice. A preliminary investigation of the optical properties of co-doped β-PbF2: Gd3+- Eu3+ ceramics was also performed. It shows that efficient Gd3+ → Eu3+ energy transfer occurs in these ceramics. The Pb2+ ions of the lattice may also be involved in the energy transfer process.
SPECTROSCOPIC PROPERTIES AND JUDD-OFELT INTENSITY PARAMETERS OF Er3+ DOPED OXYCHLOROPHOSPHATE GLASSES FOR LASER APPLICATIONS
(University of Eloued جامعة الوادي, 2018-02-05) Amrouch, S.; Chalal, M.; Kermaoui, A.; Oulebsir, A.; Zaiba, S.; Zanane, H.; Djouama, T.; Abdedou, N.; Ziane, O.; Lamrous, O.
A new series of Er3+ doped oxychlorophosphate glasses (NKAZCl) with the chemical composition based on (100-x) (NaPO3-KH2PO4–Al2O3-ZnCl2), with different xEr3+molar ratio (0.5≤x≤2), were prepared by conventional melting quenching method. The spectroscopic properties of proposed glasses are investigated by applied Judd-Ofelt theories to calculate the oscillator strengths Scal, the intensity parametes (2Ω ,4Ω ,6 Ω) .The absorption and emission cross section(σabs , (λ) σem (λ) respectively, and also the optical gain cross section parameter, at 1.53μm of 4 І13/2 4 І 15/ 2 transition of Er3+ ion are calculated by using Beer-Lambert law and the McCumber theory
SIMULATION STUDY OF THE PHOTOTRANSPORT IN AMORPHOUS SEMICONDUCTORS FROM TIME-OF-FLIGHT PHOTOCURRENT ANALYSIS
(University of Eloued جامعة الوادي, 2018-02-05) Serdouk, Fadila; Benkhedir, Mohamed-Lotfi
Time -of -flight transient photocurrent has been numerically analyzed. It is shown that the charge –carrier transit time can be determined in both non-dispersive and dispersive transport. It is also shown that the localized state distributions can be determined from the analysis of the photocurrent
SIMULATION OF OPTICAL PROPERTIES OF ZnO SUPERCELL BASED ON DENSITY FUNCTIONAL THORY.
(University of Eloued جامعة الوادي, 2018-02-05) Rezkallah, T.
This work presente the optical properties of ZnO semiconductor calculated by full potential linearized augmented plane wave (FP-LAPW) method with the local density approximation (LSDA) and the modified Becke-Johson (mBJ) potential. The scope of this work is to study some optical properties as (Dielctric function, Eloss Function, Refractive index …) of ZnO (1×1×1), (1×2×2) supercell in Zincblende (ZB) and Rocksalt (RS) phases. Our analysis revealed that the mBJ potential gives good results for the treatement of the d-orbitals.
PHASE STABILITY, ELECTRONIC AND OPTICAL BEHAVIOR OF PbS, PbSe AND PbTe COMPOUNDS
(University of Eloued جامعة الوادي, 2018-02-05) Megdoud, Y.; Mahdjoubi, R.; Tairi, L.; Bendjedou, H.; Ghemid, S.; Meradji, H.
Ab initio calculations based on density functional theory using the full potential linearized augmented plane wave method (FP-LAPW) have been carried out to find the structural stability of different crystallographic phases, the electronic and optical properties of PbS, PbSe and PbTe compounds. The zinc blende (B3), rock salt (B1) and CsCl (B2). crystal structures are considered and the exchange and correlation potential is treated by the generalized-gradient approximation using the Perdew– Burke–Ernzerhof parameterization. Moreover, the modified Becke-Johnson (mBJ) scheme is also applied to optimize the corresponding potential for the band structure calculations. Results show that the rock salt phase is the stable structure in the ground state adopted by PbS, PbTe and PbSe compounds. Moreover, the band structure calculations reveal a semiconductor behavior for all the compounds. The dielectric function, reflectivity, Refractive index and absorption coefficient are calculated to investigate the optical properties.
OPTICAL AND PHOTO-ELECTROCHEMICAL CHARACTERIZATION OF NANOSTRUCTURES DEPOSITED ON FTO SUBSTRATE
(University of Eloued جامعة الوادي, 2018-02-05) Bouderbala, I.Y.; Herbadji, A.; Mentar, L.
In this study, electrodeposition was used to deposit Cu2O doped Cl thin films on FTO substrates. The effect of Cl- ions on optical properties was studied. Photoresponse of the films shows that the conduction type change from p-type to n-type behavior of Cu2O in photoelectrochemical cells. The X ray diffraction (XRD) shows that our samples were pure Cu2O. The optical characterization of Cu2O was studied by analyzing the nanostructure transmission spectrum. The thickness and the refractive index of Cu2O nanostructures were determined using the envelop method, the optical gap (Eg) and the Urbach energy (Eu) were also calculated. It was found that the thickness and refractive index increases with increasing in copper chloride concentration
O-AMINUMBENZOYLHYDRAZIDUM DI CHLORIDE
(University of Eloued جامعة الوادي, 2018-02-05) Gheribi, Rima.; Merazig, Hocine.; Ghallab, Rochdi; Dénès, Georges
The title compound was prepared and determined by x-ray diffraction analysis. The structure of the new compound crystalline in the triclinic system space group with a=4.817 (5)Å, b=9.150 (5)Å, C=12.033 (5)Å and α=109.161 (5)°, β=92.209 (5)°and γ=101. 155 (5)°, Z=2.The final refinement of goodness of fit on F2=1.052 The asymmetric unit of the compound contains two parts, one organic cation and two inorganic anion and the crystal structure was ensured by two types of interaction entered and intermolecular hydrogen bonds along the C axis N-H… Cl and N-H… O is resulting the formation of three dimensional Network and reinforcing the cohesion of the structure they have many area of application such us gas storage, catalyse...etc
Numerical comparative study of Nd: YAG solar laser power in end-pumping and sidepumping configurations
(University of Eloued جامعة الوادي, 2018-02-05) MEHELLOU, Saïd; REHOUMA, Ferhat
Solar-pumped solid-state lasers are promising for many applications. Since the report of the first sun-pumped solid-state laser, several pumping schemes have been proposed for enhancing the solar laser performance. Although the most efficient laser systems have end-pumping approaches, side-pumping configurations are very suitable for laser power scaling. Here we report numerical comparisons between the performances of Nd: YAG solar lasers by using either end-pumping or side-pumping techniques. In end-pumping configuration, a conical-shaped fused silica light-guide with 3D-CPC output end is used to transmit, compress the concentrated solar radiation from the focal zone of the parabolic mirror into a 4 mm diameter, 30 mm length Nd: YAG rod, within a conical pump cavity, which enables the multi-pass pumping through the laser rod. In side-pumping configuration, a fused silica light-guide with rectangular cross-section is used to collect nearly the same concentrated solar power from the focal zone. The guide also acts as a beam homogenizer by transforming the near-Gaussian profile of the concentrated light spot, incident on its input face, into a uniform rectangular light distribution at its output end. A 2D-CPC cavity is employed in this approach to enhance both the absorbed pump power and distribution along a 4 mm diameter, 30 mm length Nd: YAG rod. Uniform absorption along the rod is achieved, reducing the thermal loading problems. For 900W/m2 solar irradiance, the maximum solar laser power of 60 W is calculated for the end-pumping configuration, corresponding to 40 % enhancement over the collection efficiency of side pumping configuration.
Modélisation De La Diffraction Des faisceaux Laser D'ordre supérieur
(University of Eloued جامعة الوادي, 2018-02-05) Mihoubi, Karima; Bencheikh, Abdelhalim
Dans notre travail on a fait une modélisation de la diffraction des faisceaux lasers de type Hermite-Gauss d'ordre multiple afin de trouver un modèle mathématique général exprimant les distributions du champ électrique et de l'intensité lumineuse, ce développement facilite la caractérisation des faisceaux lasers après diffraction (calcul du facteur de qualité M²,etc…), d'autre part les faisceaux obtenus après diffraction peuvent avoir des formes intéressantes
MISE EN FORME DES FAISCEAUX LAGUERRE-GAUSS LGp0 PAR UNE OUVERTURE CIRCULAIRE
(University of Eloued جامعة الوادي, 2018-02-05) Chabou, S.; Abdelhalim, B.
Dans cette communication on présente une simulation numérique de la diffraction des faisceaux Laguerre Gauss radiaux de symétrie cylindrique par une ouverture circulaire en utilisant l’intégrale de Fresnel-Kirchhoff. Cette étude sera menée dans le plan focal d’une lentille convergente. Les résultats montrent qu'un simple diaphragme peut jouer le rôle d'un élément optique diffractif reconfigurable très peu coûteux permettant la génération de toute la famille d'un faisceau LGp0 (tels que ; LG(p-1)0, LG(p-2)0, LG(p-3)0,………., LG00) à partir d'un seul mode d'ordre supérieur.
MISE EN EVIDENCE DE DEFAUTS ACTIFS LUMINESCENTS DANS LE ZnO PAR PHOTOLUMINESCENCE ET TSC
(University of Eloued جامعة الوادي, 2018-02-05) Chabane, L.; Zebbar, N.; Zaaboub, Z.; Tata, S.; Kechouane, M.
In this work, we have, experimentally, investigated the luminescence defect in ZnO thin film deposited onto crystalline Si substrate. The studied film was deposited by DC reactive sputtering technique, under (Ar + O2) plasma at 373 K, durig 1 hour and annealed at 573 K during 1 hour. The UV-Visible transmittance and ellipsometrie characterisations revealed that the optical energy band gap and the film thickness are respectively, around to 3.35 eV and 50 nm. The photoluminescence spectrum measured at room temperature indicates that the deposited film presente a UV luminescence peak at 384 nm (3.21 eV). The current-potentialtemperature and the stimulated current measurements indicate the presence of a shallow level with activation energy around to 0.35 eV, attributed to the interstial zinc or oxygen vacancies.

Browse

Recent Submissions