Data acquisition, parameter extraction and characterization of active components using integrated instrumentation system

A data acquisition, parameter extraction and characterization system for electronic active components is presented in this paper. High sensitivity measuring equipments were used for data acquisition and effective extraction models based on optimization techniques developed to obtain the parameters of p-n junction diodes, Schottky diodes, field effect transistors and bipolar junction transistors. The performance of the developed extraction techniques are apparent via comparing experimental data with Spice simulated data using the model parameter that is graphically extracted and also those extracted using optimization techniques. The performance of the developed extraction techniques has been demonstrated by comparing the experimental characteristics with Spice simulated curves using default parameters and model parameters extracted using graphical and optimization techniques. The relative excursions of the simulated I-V characteristics of most investigated devices were less than 2.5 % with respect to the experimental curves, which shows the accuracy and effectiveness of the developed system. A number of software routines have also been implemented under Matlab environment to extract the Spice model parameters for different electronic devices

Taxonomy and chemical characterization of new antibiotics produced by Saccharothrix SA198 isolated from a Saharan soil

Actinomycete strain SA198, isolated from a Saharan soil sample of Algeria, exhibited antimicrobial activity against Gram-positive and Gram-negative bacteria, and phytopathogenic and toxinogenic fungi. The morphological and chemotaxonomic characteristics of the strain were consistent with those of the genus Saccharothrix. Analysis of the 16S rRNA gene sequence of strain SA198 showed a similarity level ranging between 97.2 and 98.8% within Saccharothrix species, S. australiensis being the most closely related. Two new active products were isolated by reverse HPLC using a C18 column. The ultraviolet–visible (UV–VIS), infrared (IR), mass, and 1Hand 14C nuclear magnetic resonance (NMR) spectra showed that these products were new bioactive compounds. The minimum inhibitory concentrations of these antibiotics showed a strong activity against fungi and moderate activities against Gram-positive and Gram-negative bacteria

Synthesis, spectroscopic and electrochemical properties of new covalent assemblies between TTF and various acceptors

Five new acceptor-π–TTF-π-acceptor (A–D–A) triads that contain pyridine, quinoline, nitrophenyl or nitrofuryl groups as acceptor unit have been synthesized by two-fold Wittig olefination reactions and their electrochemical behavior has been studied by cyclic voltammetry (CV). The intramolecular charge transfer (ICT) band in these molecules was characterized by UV–visible electronic absorption spectroscopy and these studies were completed by DFT calculations in the gas phase. These materials appear to be good candidates for the preparation of electroactive discrete metal complexes or coordination polymers as well as for the preparation of radical cations salts

Angiodysplasies des maxillaires de l’enfant

Les angiodysplasies des maxillaires sont des affections rares et graves. Leur mauvais pronostic est surtout lié aux complications hémorragiques redoutables, dues le plus souvent à des extractions dentaires abusives sans examens radiologiques préalables. L’angio-IRM a permis d’une manière non invasive une meilleure connaissance de ces lésions en étudiant leur angio-architecture et leur hémodynamique. Jadis, le seul traitement efficace consistait en une exérèse chirurgicale mutilante entraînant des complications esthétiques et fonctionnelles sévères avec une morbidité importante. Actuellement, la radiologie interventionnelle a révolutionné la prise en charge grâce à l’artériographie hypersélective et àla découverte de nouveaux matériaux d’obturation plus faciles à manier. L’embolisation hypersélective est devenue l’arme de première intention en raison de son caractère conservateur et de son faible taux de  complications. Le but de ce travail est de rappeler les différents aspects étiopathogéniques, cliniques et para cliniques des angiodysplasieset de définir l’attitude thérapeutique.Mots clefs : angiodysplasie, embolisation, chirurgie

de Haas-van Alphen oscillations in the underdoped cuprate YBa2_2Cu3_3O6.5_{6.5}

The de Haas-van Alphen effect was observed in the underdoped cuprate YBa$_2$Cu$_3$O$_{6.5}$ via a torque technique in pulsed magnetic fields up to 59 T. Above an irreversibility field of $\sim$30 T, the magnetization exhibits clear quantum oscillations with a single frequency of 540 T and a cyclotron mass of 1.76 times the free electron mass, in excellent agreement with previously observed Shubnikov-de Haas oscillations. The oscillations obey the standard Lifshitz-Kosevich formula of Fermi-liquid theory. This thermodynamic observation of quantum oscillations confirms the existence of a well-defined, close and coherent, Fermi surface in the pseudogap phase of cuprates.Comment: published versio

A 31T split-pair pulsed magnet for single crystal x-ray diffraction at low temperature

We have developed a pulsed magnet system with panoramic access for synchrotron x-ray diffraction in magnetic fields up to 31T and at low temperature down to 1.5 K. The apparatus consists of a split-pair magnet, a liquid nitrogen bath to cool the pulsed coil, and a helium cryostat allowing sample temperatures from 1.5 up to 250 K. Using a 1.15MJ mobile generator, magnetic field pulses of 60 ms length were generated in the magnet, with a rise time of 16.5 ms and a repetition rate of 2 pulses/hour at 31 T. The setup was validated for single crystal diffraction on the ESRF beamline ID06

NEW VIDEO COMPRESSION USING MSPIHT3D

ABSTRACTIn this paper, we propose a new approach to video compression based on the principle of Set Partitioning In Hierarchical Treealgorithm (SPIHT). Our approach, the modified SPIHT3D (MSPIHT3D), distributes entropy differently than SPIHT3D andalso optimizes the coding. This approach can produce results that are a significant improvement on the Peak Signal-to-NoiseRatio (PSNR) and compression ratio obtained by SPIHT3D algorithm, without affecting the computing time.KEYWORDS: video compression,, MSPIHT3D, arithmetic Coding, PSNR, Compression ratio

High frequency magnetic oscillations of the organic metal θ\theta-(ET)4_4ZnBr4_4(C6_6H4_4Cl2_2) in pulsed magnetic field of up to 81 T

De Haas-van Alphen oscillations of the organic metal $\theta$-(ET)$_4$ZnBr$_4$(C$_6$H$_4$Cl$_2$) are studied in pulsed magnetic fields up to 81 T. The long decay time of the pulse allows determining reliable field-dependent amplitudes of Fourier components with frequencies up to several kiloteslas. The Fourier spectrum is in agreement with the model of a linear chain of coupled orbits. In this model, all the observed frequencies are linear combinations of the frequency linked to the basic orbit $\alpha$ and to the magnetic-breakdown orbit $\beta$.Comment: 6 pages, 4 figure

Experimental-numerical characterization of the fracture behaviour of P264GH steel notched pipes subject to internal pressure

The rupture phenomenon of a mechanical structure requires critical consideration, because of its safety constructions. A detailed experiment of material features as well as the Young’s modulus, yield strength, material toughness or fracture resistance provides useful information to predict the life integrity of a pipe structure. This paper presents the most accurate experimental techniques for characterization of a pipe-like structure to assess its reliability. Standard traction tests, dynamic Charpy tests and pressure tests were performed to envisage the crack propagation progress. Detailed information on fracture process was obtained by a robust numerical approach using the finite element method