Glass transition investigated by a combined protocol using thermostimulated depolarization currents and differential scanning calorimetry

Relaxation times of bisphenol A polycarbonate around the glass transition temperature are estimated using the combination of differential scanning calorimetry (DSC) and thermostimulated depolarization currents (TSDC). These measurements are performed using samples with different thermal histories below and above the vitrification transformation. This protocol enables the extension of the range of equilibrium relaxation times measured by dielectric spectroscopy. By this mean we may recalculate the values of the Kauzmann temperature and fragility index

Reliable characterization of organic dielectrics degraded by high electric field

The study of the degradation of organic dielectrics is of great interest for industrial applications, especially in electrical industry. So great, that other applications are also being developed in the fields of optical communications, information storage, stacked memories or manufacturing new components in micro technology, mainly in the fields of MEMS and sensors. Under the same conditions of temperature and of high intensity electric field during operation, we present results on Poly Ethylene Terephthalate (PET) which is the most useful material; the degradation considered here is induced by high electric field in ambient atmosphere with a high voltage range scaled around on 12kV during 1h.The physical and thermal characterization is carried out by an implementation of an experimental technique very fine high sensitivity and high accuracy measures such as Broadband Dielectric Spectroscopy (BDS) and Differential Scanning Calorimetry (DSC). Phase transition, relaxation mode changes, molecular relaxation and trapping effect will be discussed

The mean circulation of the southwestern Mediterranean Sea: Algerian Gyres

This is a study about the general circulation of the southwestern Mediterranean Sea based on observations of currents carried out in the southwestern Mediterranean Sea in the framework of the Mass Transfer and Ecosystem Response (MATER) program (EEC/MAST3 program). From July 1997 to August 2002, profiling floats (MEDPROF experiment), isobaric floats (LIWEX experiment), and moored current meters (ELISA experiment) give evidence of two large-scale barotropic cyclonic circulations, the here-called Western and Eastern Algerian Gyres, centered around [3730′N, 230′E] and [3830′N, 600′E], respectively. These gyres have typical horizontal scales of 100–300 km and are characterized by orbital velocities of about 5 cm/s corresponding to rotational periods of about 4 months. They are strongly related to the bottom topography of the basin and to the planetary vorticity gradient: closed f/H isocontours (f is the planetary vorticity, H the water depth) correspond to the locations of the gyres and favor such circulations as free geostrophic modes. A linear and barotropic model is used to investigate the possibility of wind driving, but the results suggest that the wind stress is not responsible for establishing such circulations. The boundary currents flowing along the continental slope of Africa, Sardinia, and the Balearic Islands are proposed to be the main drivers of these gyres

Bayoud disease of date palm in Algeria: History, epidemiology and integrated disease management

The bayoud is transmitted by the fungus Fusarium oxysporum f. sp. albedinis, which causes drying and rapid die back. To date, the disease has destroyed more than 12 million date palms in Morocco, or two-thirds of the producers of the best dates trees in this country, and three million of palm trees in Algeria with the threat of the spread of this disease to oasis southeast of Algeria. The research on this disease is very few in Algeria, in this case, this work had objective to study the growth and spread of the disease bayoud on the Algerian palm. is based on the observation of symptoms on palms, it showed that all regions with palm in Bechar (Saoura) and in Adrar (Touat), affected with some palm of Ghardaïa. Prophylactic measures are taken to protect and preserve our date resources (including 'Deglet Nour') in free palm (Zibans and Oued Righ in southeast of Algeria) by improving irrigation methods and the use of free releases, and determination date palm cultivars resistant to the fungus as Takarboucht in oasis of Ghardaïa and Adrar, Hmira and Hartan for Bechar’s date palms.Keywords: Date palm, bayoud disease, saoura, resistance, IPM

Influence of processing parameters on electrical properties of polysilicon/ monosilicon junctions

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Effect of a magnetic field on the conduction mechanism in Silicon P+N junctions

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Deep levels induced by low energy B+ implantation into Ge-preamorphised silicon in correlation with end of range formation

International audienceIt is well established that low energy B+ ion implantation into Ge- (or Si) implantation pre-amorphised silicon allows ultra-shallow p+n junctions formation. However, this process is known to generate defects such as dislocation loops, vacancies and interstitials which can act as vehicles to different mechanisms inducing electrically active levels into the silicon bulk. The junctions studied have been obtained using 3 keV/ implantation into Ge-implantation pre-amorphised substrates and into a reference crystalline substrate. Accurate measurements using deep level transient spectroscopy (DLTS) and isothermal transient capacitance ΔC(t,T) were performed to characterise these levels. Such knowledge is crucial to improve the device characteristics. In order to sweep the silicon band gap, various experimental conditions were considered. The analysis of DLTS spectra have first showed three deep levels associated to secondary induced defects. Their concentration profiles were derived from isothermal transient capacitance at depths up to 3.5 μm into the silicon bulk and allowed us to detect a new deep level. The evolution of such defect distribution in correlation with the technological steps is discussed. The end of range (EOR) defect influence on electrical activity of secondary induced defects in ultra-shallow p+n diodes is clearly demonstrated

Electrical characterization and modelling of high energy pre-amorphized P+N silicon junctions

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Response of electrically active defects in P/sup +/N junctions when applying a magnetic field

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Thermal behavior Spice study of 6H-SiC NMOS transistors

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