Behavior of cereal’s varieties in the presence of Heterodera avenae woll (heteroderidae, tylenchida) cyst nematode in Tiaret Area (Algeria)

The behaviour of cereals varieties (Ofanto, Waha and Vitron for durum wheat; Anza and HD1120 for bread wheat and Saida with Acsad for barly) were tested towards Heterodera avenae. The analysis of the variance reveals that the nematode has an effect on the development of durum wheat for the number of ear per seedling and the weight of thousand seeds, with respectively: P = 0, 0033 and P = 0,000, for the infested varieties and the witnesses. Common wheat shows a highly significant difference (P= 0, 0000) for the varieties infested and pilot and of the same for the barley, but with a significant difference with: P= 0,0002, between the varieties of barley. The two varieties of barley were different when with the weight from 1000grains. The ACP of any species confers that Saida is the most sensitive variety followed by Ofanto and Anza to attack of this nematode.Keywords: Nematode; Heterodera; cereals; varieties; behaviou

Properties of Undoped and (Al, In) Doped ZnO Thin Films Prepared by Ultrasonic Spray Pyrolysis for Solar Cell Applications

Zinc oxide (ZnO) is an n-type semiconductor with a large optical gap (3.4 eV) belonging to the transparent conductive oxides family (TCO). Strongly present as optical window in the chalcopyrite based structures CIGS and CIS. The structural, morphological, optical and electrical properties of ZnO thin films deposited onto glass substrates by ultrasonic spray pyrolysis (USP) technique have been investigated. For comparison and a better understanding of physical properties of undoped and (Al, In) doped ZnO thin films, a number of techniques, including XRD, SEM, optical absorption method (UV) and four-point probe technique were used to characterize the obtained ZnO thin films. Structural analysis shows that all the films were found to be polycrystalline with a wurtzite structure and show a (1 0 1) preferential growth. Besides, we noted that the preferred orientation does not depend on the nature of dopant. The band gaps (Eg) varied from 3.35 to 3.37 eV by Al and In dopants

Half-metallic properties in Co2XSn (X = Ti, V and Cr) full-Heusler compound

First-principles calculations based on density functional theory (DFT) confirm the half-metallic ferromagnetism in both [Formula: see text] and [Formula: see text], and the nearly half-metallic ferromagnetism in [Formula: see text] Heusler alloys with the [Formula: see text]-type structure [Formula: see text]. The electronic band structures and density of states (DOS) calculations of the [Formula: see text] and [Formula: see text] compounds show that the spin-up electrons are metallic, whereas the spin-down bands are semiconducting with a gap of 0.47 eV and 0.53 eV, respectively, with 0.21 eV and 0.36 eV as a spin-flip gap, respectively. The [Formula: see text] and [Formula: see text] Heusler were half-metal compounds with magnetic moment of [Formula: see text] and [Formula: see text] at the equilibrium lattice constants [Formula: see text] Å and [Formula: see text] Å, respectively, which agrees with the Slater–Pauling rule, and have 100% polarization for a wide range of lattice parameters. The [Formula: see text] is a nearly half-metal (NHF) compound with magnetic moment of [Formula: see text] and 92.9% polarization at the equilibrium lattice constants [Formula: see text] Å and acquire half-metal behavior under the pressure 16.70 GPa. </jats:p

Investigation of optoelectronic and thermoelectric properties of half-metallic BaRuO₃ using DFT+U

We have studied the structural, electronic, magnetic, thermoelectric and optical properties of the half-metal BaRuO3 using the accurate full-potential linearized augmented plane wave (FP-LAPW) method based on the density functional theory (DFT). The generalized gradient approximation (GGA) was used to treat the exchange and correlation potential. The GGA[Formula: see text] approximation was also used to enhance the description of the electronic structure after calculating theoretically the Coulomb repulsion ([Formula: see text][Formula: see text]eV). The ferromagnetic (FM) phase of BaRuO3 is more stable. This result is in accordance with experimental and theoretical calculations. The calculated magnetic moments in BaRuO3 were found to arise especially from the Ru-4d state electrons. We have obtained the semiconductor gap (0.9[Formula: see text]eV) in spin-up while in spin down, the metal character was dominant, and therefore BaRuO3 has a half-metallic behavior. The thermoelectric efficiency was 0.12 at room temperature. Here we have considered only the electronic thermal conductivity, we have not included the lattice thermal conductivity. The relaxation time was assumed constant. The [Formula: see text] approximation was also used to analyze the optical properties by determining the complex dielectric function from which are derived the other parameters. </jats:p

Вплив товщини пластини та кількості сіток трафаретного друку на Al-BSF у кристалічних кремнієвих сонячних елементах

У роботі були проведені експериментальні дослідження процесу легування алюмінієвих (Al) паст, надрукованих трафаретним друком на кремнієвих поверхнях для сонячних елементів. Досліджений вплив товщини пластини та кількості сіток трафаретного друку на властивості поля задньої поверхні Al (Al-BSF) кремнієвих сонячних елементів Чохральського (Cz-Si). Використовувалися екрани з різною кількістю сіток (150, 200 і 400 меш) для друку різної кількості пасти Al (7, 9,4 та 12 мг/см2). Швидкий термічний відпал (RTP) при 750 °C і 800 °C протягом 60 с був застосований для формування ALBSF. SEM показав утворення шорсткої поверхні з шаром легуючого шару товщиною 4,31 мкм на об’ємній кремнієвій пластині. Аналіз ECV та SIMS показав, що пікова температура відпалу 750 °C і кількість пасти Al 12 мг/см2 підходять для створення оптимального Al-BSF. Ця робота виявила, що на властивості Al-BSF сильно впливає кількість меш, яка використовується для трафаретного друку пасти Al. Однак не було помічено монотонного зв’язку з товщиною пластини. Маска з 150 меш дозволила отримати високі концентрації Al на поверхні, максимальну глибину дифузії та більший середній час життя носіїв заряду.In this study, experiments on the alloying process from screen-printed aluminum (Al) pastes on silicon surfaces for solar cell applications were conducted. We investigated the effect of wafer thickness and screen-printing mesh counts on the Al back surface field (Al-BSF) properties of Czochralski silicon (Cz-Si) solar cells Screens with different mesh counts (150, 200 and 400 mesh) were used to print variable amounts of Al paste (7, 9.4 and 12 mg/cm2). Rapid thermal annealing (RTP) annealing processes of 750 °C and 800 °C for 60 s were applied to form AL-BSF. SEM micrographs showed the formation of a rough surface with 4.31 µm alloying layer over bulk Si wafer. ECV and SIMS analysis showed that an annealing peak temperature of 750 °C and an amount of Al paste of 12 mg/cm2 are suitable for the creation of an optimal Al-BSF. This work revealed that Al-BSF properties are strongly affected by the mesh counts used in screen-printing of Al paste. However, no monotonic relationship was noticed with the wafer thickness. The mask with 150 meshes allowed to obtain high Al concentrations at the surface, maximum diffusion depth and longer average lifetimes of charge carriers

Enhanced optical and thermoelectric properties of ZnO by tin and fluorine codoping: First-principles DFT calculations

Ab initio density functional calculations of the structural, optoelectronic, thermoelectric and thermodynamic properties of ZnO codoped with tin and fluorine with possible application as Transparent Conductive Oxides (TCO’s), are reported in this work. This study shows that incorporation of Sn and F into the ZnO matrix converts it to a degenerate semiconductor. The calculated optical absorption coefficients show that the four compounds ZnO, Sn:ZnO, F:ZnO and Sn:F:ZnO have transparent properties in the visible range. At 900[Formula: see text]K, the Seebeck coefficient of Sn:F:ZnO is greatly improved with respect to the undoped ZnO. A maximum electrical conductivity value of [Formula: see text]S cm[Formula: see text]s[Formula: see text] is predicted for Sn-doped ZnO. ZT increases with temperature to a maximum value of 0.13 at 900[Formula: see text]K for tin and fluorine codoped ZnO. </jats:p