https://dspace.univ-ouargla.dz/jspui/handle/123456789/8460 2026-04-04T19:41:17Z https://dspace.univ-ouargla.dz/jspui/handle/123456789/9970 Titre: Caractérisations Structurale, Optique et Electrique des Couches Minces du SnO2, Non Dopé et Dopé au Lithium, Elaborées par Spray Ultrasonique Auteur(s): Atmane BEN HAOUA; Achour RAHAL; Boubak er BEN HAOUA; Soumaia ABBAS Résumé: In this work, undoped and Li doped tin oxide thin films (SnO2 and Li: SnO2) were prepared by spray ultrasonic technique on ordinary heated, at 480 ° C, glass substrates during three minutes. The solution precursor was SnCl2 dissolved in methanol and for doping LiCl2 was added in the precursor solution. X-ray diffraction (XRD), UV-Visible spectroscopy and four point prop were employed to investigate the structural, optical and electrical characteristics of the films before and after doping. XRD showed that the films were tetragonal routile casteriste with (110) and (211) as preferred orientation for undoped and Li doped SnO2 respectively. Grain seizes were found to be in 29-33nm average. UV-Visible spectrum revealed that the prepared SnO2 films have transmittance value laying between 60-95% in visible region and optical gap varied between 3.72 to 3.87 eV for the undoped to 5.0%wt Li doped one respectively. Thin film thickness was estimated to be 200nm for the all samples. From electrical characterisation it was found that sheet resistance increases from 600 to 8.3x105Ω/cm2 after doping with 5.0%wt Li concentration which lead to an decrease in conductivity of the films Description: Annales des Sciences et Technologie 2015-05-01T00:00:00Z https://dspace.univ-ouargla.dz/jspui/handle/123456789/9974 Titre: A comparative study of the phytochemical, antioxidant and anti-inflammatory properties of ethyl acetate extract of Asphodelus tenuifolius Cav recovered by different extraction techniques Auteur(s): Salah Eddine LAOUINI; Abdelhamid KHELEF; Segni LADJEL; Mohamed Ridha OUAHRANI Résumé: In this study, phytochemical, in vitro antioxidant activities and anti-inflammatory of bioactive components of Asphodelus tenuifolius Cav extracts by classical extraction method (CE), Soxhlet extraction (SE), ultrasonic extraction (UE) and microwave extraction (ME) were investigated. The total phenolic, flavanoids, condensed tannins and anthocyanin content were determined by a spectrophotometric method. β-Carotene, ABTS, and FRAP radical-scavenging were applied to test the antioxidant activities. The results indicated that the classical method extraction exhibited the strongest antioxidant activities. The contents of polyphenols in the CE were significantly higher than those by other extraction methods, which was possibly responsible for the higher antioxidant activities of the Asphodelus tenuifolius Cav by CE. From the results we can draw the conclusion that not only the more bioactive components are obtained but also the extract has better free radical and reactive oxygen species scavenging activities through classical extraction method. These findings further illustrate that classical extraction has a bright prospect for extracting active ingredients from plant materials. The study concludes that Asphodelus tenuifolius Cav possess diverse therapeutic potentials which might be useful in development of drugs or their precursors Description: Annales des Sciences et Technologie 2015-05-01T00:00:00Z https://dspace.univ-ouargla.dz/jspui/handle/123456789/9971 Titre: Simulation d’une cellule solaire en couche mince à base de Cuivre-Zinc-Étain Sulfure/Séléniure Cu2ZnSn(S,Se)4 Auteur(s): Abdelkader BENMIR; Mohamed Salah AIDA Résumé: The aim of this work is to do a simulation of a Cu2ZnSn(S,Se)4 thin film photovoltaic solar cell in order to link the characteristics of this cell to the materials parameters in order to improve its performances. It is found that, to spread the space charge zone on both layers of the junction, the doping concentrations of the CdS window layer and the Cu2ZnSn(S,Se)4 absorber layer should be in order of 1015cm-3 and 1014cm-3 respectively. Furthermore, the cell performances are almost invariables while the thickness of the window layer is equal to or less than the width of the space charge zone. But, as soon as it exceeds this width, a slight reduction in these performances is observed. However, the absorber layer has an optimal value of the thickness in the order of 3μm, which equal to the width of the depletion zone of its side that corresponds to the values of doping concentrations given above. An optimum value of the absorber gap of around 1.5 eV is obtained. This value is the compromise between the decreases of the short circuit current density and the increases of the open circuit voltage with the increases of the gap. This leads to a maximum cell efficiency of 12.3%. Description: Annales des Sciences et Technologie 2015-05-01T00:00:00Z https://dspace.univ-ouargla.dz/jspui/handle/123456789/9973 Titre: Etude de l’activité antioxydante des extraits phénoliques de l’Atriplex halimus L et de l’Haloxylon scoparium pomel du Sahara septentrional Auteur(s): Samira BELHADJ TAHAR; Mahfoud HADJ MAHAMMED; Mohamed YOUSFI Résumé: The antioxidants are the subject of many studies, because in addition to their use as preservatives in food products by replacing the synthetic antioxidants, they intervene in the treatment of many diseases. In this study, we evaluated the antioxidant properties of leaves of atriplex halimus L as well as flowers and stems of haloxylon scoparium pomel. Butanolic Fractions of flowers of the two plants have a higher total phenols content; the fraction of ethyl acetate and butanol, for these two plants, presents a better total antioxidant capacity, and higher activity to trap the DPPH radical and the ABTS radical cation Description: Annales des Sciences et Technologie 2015-05-01T00:00:00Z