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Electrical Parameters (electrical + parameter)
Selected AbstractsStudies on multiphased mixed crystals of NaCl, KCl and KICRYSTAL RESEARCH AND TECHNOLOGY, Issue 1 2009M. Priya Abstract Multiphased mixed crystals of NaCl, KCl and KI were grown by the melt method, for the first time. Densities and refractive indices of all the grown crystals were determined and used for the estimation of the composition in the crystal. Atomic absorption spectroscopic measurements were done to estimate the metal atom contents in the crystal. Lattice parameters and thermal parameters (Debye-Waller factor, mean square amplitude of vibration, Debye temperature and Debye frequency) were determined from the X-ray powder diffraction data. DC and AC electrical measurements were done at various temperatures ranging from 40 to 150°C. Activation energies were also estimated. The observed lattice parameters showed that the system exhibits three phases each nearly corresponds to NaCl, KCl and KI. The thermal and electrical parameters show a highly nonlinear bulk composition dependence. Results are reported. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Physical properties of Dy and La doped SnO2 thin films prepared by a cost effective vapour deposition techniqueCRYSTAL RESEARCH AND TECHNOLOGY, Issue 10 2006J. Joseph Abstract Stannous oxide (SnO2) thin film is one of the most widely used n-type transparent semi-conductor films in electronics, electro-optics and solar energy conversion. By achieving controlled non-stoichiometry, we can get good transparency and high electrical conductivity simultaneously in SnO2 thin films. Dy and La doped SnO2 thin films have been prepared by a cost effective vapour deposition technique. The structural, photo-electronic, optical and electrical properties of the doped and undoped films were studied. The results of X-ray Diffraction studies reveals the polycrystalline nature of the films with preferential orientation along the (101), (211) and (301) planes and their average grain size variation for different deposition temperature. Photoconductivity and Photovoltaic studies of the films were also performed. The optical properties of these films were studied by measuring their optical transmission as a function of wavelength. The optical transmission is found to be increased on Dy doping and decreased on La doping. The band gap, refractive index and thickness of the films were calculated from U-V transmittance and Absorption graphs. The optical band gap of undoped film is found to be 4.08 eV, but on doping it shifts to lower energies and then increases on increasing the concentration of both dopants. Its electrical parameters such as sheet resistance, resistivity, mobility, Hall coefficient, and carrier concentration were determined by Four Probe, Van der Pauw and Hall Probe method. On doping with Dy, carrier conversion takes place from n-type to p-type and p-conductivity dominates. On La doping no carrier conversion takes place but resistivity decreases. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] A compact one-dimensional modal FDTD methodINTERNATIONAL JOURNAL OF NUMERICAL MODELLING: ELECTRONIC NETWORKS, DEVICES AND FIELDS, Issue 1-2 2008Shuiping Luo Abstract The finite-difference time-domain (FDTD) method is an effective technique for computing wideband electrical parameters such as scattering parameters of waveguide structures. in the computations, a known incident is normally required and is usually obtained with a simulation of a long uniform structure. For a three-dimensional problem, simulation of a long structure can be very memory- and CPU time-intensive. In addition, effective absorbing boundary conditions are needed to effectively terminate the structure even at and below the cutoff frequencies. To address these issues, many one-dimensional FDTD methods and absorbing schemes were proposed. However, they all have dispersion characteristics different from those of the conventional FDTD method, leading to undesired errors or reflections. In this paper, a new one-dimensional scheme is developed that has numerical dispersion characteristics very similar to that of the conventional FDTD method. When used as the absorbing boundary condition, it generates reflections of less than ,200,dB even at and below the cutoff frequencies for the considered modes. When used to obtain the incident wave, its results have difference of less than ,200,dB from that produced by the conventional FDTD method. Copyright © 2007 John Wiley & Sons, Ltd. [source] On the transmission properties of left-handed microstrip lines implemented by complementary split rings resonatorsINTERNATIONAL JOURNAL OF NUMERICAL MODELLING: ELECTRONIC NETWORKS, DEVICES AND FIELDS, Issue 2 2006M. Gil Abstract In this paper, the transmission properties of left-handed microstrip lines implemented by etching complementary split rings resonators (CSRRs) and capacitive gaps in the ground plane and conductor strip, respectively, are investigated. To this end, we make use of the lumped element equivalent circuit model of the structure, from which an accurate analysis is carried out, and the influence of the main electrical parameters on the transmission properties is pointed out through electrical simulations. Aspects such as bandwidth and in-band ripple control are discussed in detail. The influence of the geometrical parameters is also discussed and interpreted to the light of the equivalent circuit model. From the results obtained, there are inferred design guidelines that are suitable for the design of metamaterial transmission lines subjected to specifications. Copyright © 2006 John Wiley & Sons, Ltd. [source] Translocation of viable Aeromonas salmonicida across the intestine of rainbow trout, Oncorhynchus mykiss (Walbaum)JOURNAL OF FISH DISEASES, Issue 5 2006F Jutfelt Abstract The pathogenic bacterium Aeromonas salmonicida is the causative agent of the destructive disease furunculosis in salmonids. Horizontal transmission in salmonids has been suggested to occur via the skin, gills and/or intestine. Previous reports are contradictory regarding the role of the intestine as a route of infection. The present study therefore investigates the possibility of bacterial translocation across intestinal epithelia using Ussing chamber technology, in vitro. Intestinal segments were exposed for 90 min to fluorescein isothiocyanate-labelled pathogenic A. salmonicida. Sampling from the serosal side of the Ussing chambers showed that bacteria were able to translocate across the intestinal epithelium in both the proximal and distal regions. Plating and subsequent colony counting showed that the bacteria were viable after translocation. During the 90 min exposure to A. salmonicida, the intestinal segments maintained high viability as measured by electrical parameters. The distal region responded to bacterial exposure by increasing the electrical resistance, indicating an increased mucus secretion. This study thus demonstrates translocation of live A. salmonicida through the intestinal epithelium of rainbow trout, suggesting that the intestine is a possible route of infection in salmonids. [source] Impedance measurements on oxide films on aluminium obtained by pulsed tensionsMATERIALS AND CORROSION/WERKSTOFFE UND KORROSION, Issue 1 2003K. Belmokre Anodisation; Elektrochemische Impedanzspektroskopie (EIS); pulsierende Spannung; Alterung von Oxidfilmen Abstract We have performed this study on oxide films sealed or not in boiling water. The films are first obtained on type 1050 A aluminium substrat by pulsed tensions anodizing technique, in a sulfuric acid solution. Afterwards the, Electrochemical Impedance Spectroscopy (EIS) is employed to appreciate the films behaviour in a neutral solution of 3.5% K2SO4, in which the interface processes interest only the ageing phenomenon of the oxide films and not their corrosion. We have also attempted a correlation between pulse parameters of anodization and the electrical parameters characterizing these films. The sealing influence on ageing has been studied as well. For all films, ageing is appreciated using impedance diagrams evolution versus time. The results show: , the existence of two capacitive loops confirming the presence of two oxide layers characteristic of oxide films obtained in a sulfuric acid medium. The first loop, at high frequencies, is related to the external porous layer and the second one, at lower freqencies, is related to the internal barrier layer. , the thickness of the barrier layer varies between 25 and 40 nm in relation with the electrical pulse parameters. , the sealing acts favorably against anodic oxide films ageing. Impedanzmessungen an durch pulsierende Spannung erzeugten Oxidfilmen auf Aluminium Die vorliegenden Untersuchungen wurden an versiegelten und nicht versiegelten Oxidfilmen in kochendem Wasser durchgeführt. Die Filme wurden zuerst auf Aluminiumsubstrat des Typs 1050A durch anodische Technik mit pulsierender Spannung in einer Schwefelsäurelösung erzeugt. Anschließend wurde die elektrochemische Impedanzspektroskopie eingesetzt, um das Filmverhalten in einer neutralen 3,5% K2SO4 -Lösung zu beurteilen, wobei bezüglich der Grenzflächenprozesse nur das Alterungsphänomen der Oxidfilme und nicht ihr Korrosionsverhalten interessierte. Es wurde versucht, eine Korrelation zwischen den Pulsparametern der Anodisierung und den elektrischen Parametern, die diese Filme charakterisieren, zu finden. Ebenfalls wurde der Versiegelungseinfluss auf die Alterung untersucht. Für alle Filme wurde die Alterung mit Hilfe der Entwicklung von Impedanzdiagrammen über die Zeit beurteilt. Die Ergebnisse zeigen: , die Existenz von zwei kapazitiven Schleifen, die die Anwesenheit von zwei Oxidschichten bestätigen, was charakteristisch ist für Oxidfilme, die in einer Schwefelsäurelösung erzeugt wurden. Die erste Schleife, bei hohen Frequenzen, bezieht sich auf die äußere poröse Schicht und die zweite, bei niedrigeren Frequenzen, bezieht sich auf die innere Barriereschicht , die Dicke der Barriereschicht variiert zwischen 25 und 40 nm, abhängig von den elektrischen Pulsparametern , die Versiegelung wirkt günstig gegenüber der Alterung des anodischen Oxidfilms. [source] New and accurate synthesis formulas for open supported coplanar waveguidesMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 2 2010S. Kaya Abstract In this article, new and accurate synthesis formulas to compute the physical dimensions of open supported coplanar waveguides (OS-CPWs) are presented. The synthesis formulas are obtained with the use of differential evolution (DE) and particle swarm optimization (PSO) algorithms. They are useful for the computer-aided design of OS-CPWs. The average percentage errors of the synthesis formulas obtained by using DE and PSO algorithms are computed to be 1.26% and 1.67%, respectively, for 4560 OS-CPW samples having different electrical parameters and physical dimensions, as compared with the results of quasi-static analysis. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 262,269, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24908 [source] Composite right/left-handed transmission line based on Koch fractal shape slot in the ground and UWB filter applicationMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 9 2009Jian An Abstract A novel composite right/left-handed transmission line is presented which is synthesized by etching Koch fractal shape slot in the ground plane and series capacitive gap in the conductor strip. Unlike the structures loaded with complementary split ring resonators, the proposed structure can operate at very wideband and is used to design an ultra-wideband (UWB) filter. The UWB filter is fabricated and tested. The relative bandwidth of the ,10 dB return loss is 128% and the insertion loss is larger than ,1.5 dB except at high frequencies. The equivalent circuit model of the proposed structure is presented and the electrical parameters are also extracted. The circuit model results are compared with the simulation and measurement results which verify that not only the extracted parameters are exact but also the equivalent circuit model is reasonable. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2160,2163, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24553 [source] Metamaterial transmission lines with tunable phase and characteristic impedance based on complementary split ring resonatorsMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 8 2009Adolfo Vélez Abstract In this article, resonant-type tunable metamaterial transmission lines with independent control over the electrical parameters of the line, that is, the electrical length and characteristic impedance, are presented for the first time. Tuning is achieved by loading a host microstrip line with varactor-loaded complementary split ring resonators (VLCSRRs) and varactor diodes. By locating the varactor diodes in series configuration with the line, outside the region occupied by the VLCSRRs, it is possible to control the characteristic impedance and the electrical length (phase shift), over a wide band. As an illustrative example, a tunable 35 ,/90° line functional between 0.4 and 0.8 GHz (which represents more than 65% tuning range), is presented and applied to the design of a transmission line power divider. The device is small and it exhibits reasonable performance. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1966,1970, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24480 [source] Parametric analysis of microstrip lines loaded with complementary split ring resonatorsMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 8 2008Jordi Bonache Abstract In this article, the effects of varying the geometry of complementary split ring resonators (CSRRs) in microstrip lines loaded with such resonant elements is analyzed. Specifically, from a parameter extraction technique previously proposed by some of the authors, the electrical parameters of CSRR-loaded lines (namely, the line inductance, the inductance and capacitance of the CSRR, and the coupling capacitance between the line and the CSRRs), are inferred. This analysis is of interest because, in spite of the existence of analytical models that predict the electrical parameters of these CSRR-loaded lines, the validity of these models is limited, and the parameter extraction method is necessary to accurately determine the electrical parameters from geometry. From the analysis carried out in this work, interesting conclusions for the design of CSRR-loaded lines are obtained. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2093,2096, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23571 [source] New and accurate synthesis formulas for multilayer homogeneous coupling structureMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 10 2007Kerim Guney Abstract New, accurate closed-form formulas for the synthesis of multilayer homogeneous coupling structure (MHCS) are presented. They are obtained by using a differential evolution algorithm (DEA), and are useful for the computer-aided design (CAD) of MHCS. The average percentage error is found to be 0.38% for 1825 MHCS samples having different electrical parameters and physical dimensions, as compared with the results of the quasi-static analysis. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2486,2489, 2007; Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/mop.22743 [source] Right Ventricular Septal Pacing: A Comparative Study of Outflow Tract and Mid Ventricular SitesPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 10 2010RAPHAEL ROSSO M.D. Background: Prolonged right ventricle (RV) apical pacing is associated with left ventricle (LV) dysfunction due to dysynchronous ventricular activation and contraction. Alternative RV pacing sites with a narrower QRS compared to RV pacing might reflect a more physiological and synchronous LV activation. The purpose of this study was to compare the QRS morphology, duration, and suitability of RV outflow tract (RVOT) septal and mid-RV septal pacing. Methods: Seventeen consecutive patients with indication for dual-chamber pacing were enrolled in the study. Two standard 58-cm active fixation leads were passed to the RV and positioned in the RVOT septum and mid-RV septum using a commercially available septal stylet (model 4140, St. Jude Medical, St. Paul, MN, USA). QRS duration, morphology, and pacing parameters were compared at the two sites. The RV lead with less-satisfactory electrical parameters was withdrawn and deployed in the right atrium. Results: Successful positioning of the pacing leads at the RVOT septum and mid-RV septum was achieved in 15 patients (88.2%). There were no significant differences in the mean stimulation threshold, R-wave sensing, and lead impedance between the two sites. The QRS duration in the RVOT septum was 151 ± 14 ms and in the mid-RV septum 145 ± 13 ms (P = 0.150). Conclusions: This prospective observational study shows that septal pacing can be reliably achieved both in the RVOT and mid-RV with active fixation leads using a specifically shaped stylet. There are no preferences in regard to acute lead performance or paced QRS duration with either position. (PACE 2010; 33:1169,1173) [source] Performance of an Autonomous Telemonitoring System in Children and Young Adults with Congenital Heart DiseasesPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 10 2008PETER ZARTNER M.D. Background:Integrated telemonitoring systems controlling circulatory and electrical parameters in adults with an implanted pacemaker have shown to be advantageous during follow-up of this patient group. In children and young adults with a congenital heart disease (CHD), these systems have to cope with a diversity of varying arrhythmias and a broad range of intrinsic cardiac parameters. Additional problems arise from the patients' growth and anatomic anomalies. Methods:Since 2005, eight young patients (age 4.1, 37 years, mean 15.5 years) with a CHD received a pacemaker or implantable cardioverter defibrillator with an autonomous telemonitoring system at our clinic. The mean follow-up time was 395 days (range 106,834 days, 8.7 patient years). Results:In seven of eight patients the system transmitted information, which led to beneficial modifications of the current antiarrhythmic therapy. In three patients the reported events were of a critical nature. One patient remained event-free for 192 days after implantation. During follow-up, 96% of the days were covered. The system also transferred additional information on the effectiveness of antiarrhythmic medication and the impact of physical activity. Conclusions:Young patients with an insufficient intrinsic heart rate or progressing arrhythmia, in addition to the conventional indications for pacemaker or defibrillator implantation, seem to profit to a high percentage from a telemetric surveillance system. The fully automated procedure of device interrogation and information transmission gives a daily overview on system function and specific arrhythmic events, especially in children who are unaware of any symptoms. [source] Extreme temperature 6H-SiC JFET integrated circuit technologyPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 10 2009Philip G. Neudeck Abstract Extreme temperature semiconductor integrated circuits (ICs) are being developed for use in the hot sections of aircraft engines and other harsh-environment applications well above the 300 °C effective limit of silicon-on-insulator IC technology. This paper reviews progress by the NASA Glenn Research Center and Case Western Reserve University (CWRU) in the development of extreme temperature (up to 500 °C) integrated circuit technology based on epitaxial 6H-SiC junction field effect transistors (JFETs). Simple analog amplifier and digital logic gate ICs fabricated and packaged by NASA have now demonstrated thousands of hours of continuous 500 °C operation in oxidizing air atmosphere with minimal changes in relevant electrical parameters. Design, modeling, and characterization of transistors and circuits at temperatures from 24 °C to 500 °C are also described. CWRU designs for improved extreme temperature SiC JFET differential amplifier circuits are demonstrated. Areas for further technology maturation, needed prior to beneficial system insertion, are discussed. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Temperature and frequency investigations of the electrical parameters in the TGS ferroelectric transitionPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 5 2010Ciceron Berbecaru Abstract Pure and D: alanina doped triglycin sulphate (TGS) crystals were grown from aqueous solutions. Fresh cleaved, polished and silver paste painted samples were temperature and frequency investigated. Pure crystals show nonreproducible values of the permittivity and dielectric loss crossing up and down the Curie point. More stable and much lower values of the permittivity and dielectric loss could be noticed for D: alanina doped crystals. Permittivity and loss values show different frequencies behavior related to polar or nonpolar state of crystals. Frequency dependence of permittivity and loss behavior could be related to the general picture of relaxation of different polarization mechanisms and their contributions to permittivity and loss values for dielectric materials. Much smaller and stable values of permittivity and loss, vs. temperature and frequency, were found for doped crystals. Experimental results point out for a more stable structure with dipoles mobility decreased of doped vs. pure TGS crystals. Thus, higher figure of merit of doped TGS crystals point to a major advantage for technical applications (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Detecting amine vapours with thermally carbonized porous silicon gas sensorPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 7 2009Mikko Björkqvist Abstract A capacitive type porous silicon based gas sensor for detecting amine vapours has been developed. The sensor is highly sensitive, e.g., to methylamine and trimethylamine vapours, and its electrical parameters recover totally after exposure to studied gases. Thermal carbonization of porous silicon under acetylene atmosphere was carried out to produce stable and attractive surface to amine vapours. The sensor response to studied amine vapours can be separated from its response to humidity changes since their electrical responses act reversely. In addition to the vapours of methylamine/water and trimethylamine/water solutions, the sensor was also used to detect different amines, which are generated during spoilage of raw shrimps and Baltic herring fillets at room temperature. Fourier Transform Infrared spectroscopy was used to detect the amine vapours and other volatile compounds simultaneously with sensor measurements. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Comprehensive analysis of advanced solar cell contacts consisting of printed fine-line seed layers thickened by silver platingPROGRESS IN PHOTOVOLTAICS: RESEARCH & APPLICATIONS, Issue 2 2009D. Pysch Abstract This work presents a detailed analysis of a new two-layer process to contact industrial solar cells. However, most of the results seem to be transferable to standard screen print paste contacts. The seed layer was created by a pad or screen printer and thickened by light-induced plating (LIP) of silver. These contact structures were investigated microscopically to gain a better understanding of the observed electrical parameters. A review of the present microscopic contact formation model for flat surfaces is presented. This model was extended and applied to surfaces textured with random pyramids. This analysis has revealed two new types of silver crystallites which can be described by a crystallographic model. The dependence of the silver crystallite density on the surface doping concentration was investigated. Next, the dependence of the contact resistance on the width of the seed layer was measured showing that the contact resistivity increases with a reduction of the seed layer width. These results have been further approved by an analysis of SEM images of wet-chemically etched contacts examining the density of crystallites and the fraction of removed SiNx layer. Contact resistance RC measurements before and after LIP of silver showed surprisingly a positive influence of the plating process on RC. A detailed microscopical analysis revealed four new possible current flow paths due to the LIP of a conventional contact or a seed layer. The results led to an extension of the existing model for a screen-printed contact. Copyright © 2008 John Wiley & Sons, Ltd. [source] In vivo DNA gene electro-transfer: a systematic analysis of different electrical parametersTHE JOURNAL OF GENE MEDICINE, Issue 11 2005Immacolata Zampaglione Abstract Background Intramuscular plasmid injection followed by electroporation is an efficient method for gene therapy or vaccination. Several protocols have been described that give good transduction levels with several reporter genes. Methods In this work we have explored the efficiency of gene delivery upon variation of the different electrical parameters such as pulse length frequency and voltage monitoring both on short- and long-term protein production. Results Having defined the best performing parameters, we have designed a short electric treatment that gives good levels of plasmid-encoded protein in different species such as mice, rabbits and monkeys. Copyright © 2005 John Wiley & Sons, Ltd. [source] | |||||||||||||