An equivalent diagram with localized constants has been created to represent the two winding transformer. The equivalent diagram with localized constants is practically independent of the transformer construction. Only the numeric constants change from one component to another. This circuit can be introduced into converter simulation software, and leads to very realistic forecasts even when working at high frequency. The

A practical universal modeling and simulation approach is presented in this paper to show that accurate battery pack simulation can be achieved if cell-to-cell variations were taken into account. A generic equivalent circuit model was used in the approach with parameters deduced from cell testing with proper protocols, which could come from live cell monitoring in a control circuitry. Using a single cell model, which was validated against experimental data and demonstrated with validity of high accuracy in predicting cell performance, we showed that such a high accuracy in single cell model is essential for a high fidelity pack simulation. It is also important to derive statistical confidence intervals accurately from experiments to characterize intrinsic cell-to-cell variations in capacity and internal resistance, which need to be considered in the pack model. If parameters for each individual cell were correctly approximated and used in the pack model, the accuracy in the prediction of pack performance could be significantly improved.

A complete analysis of low-noise 0.1 m gate AlInAs/GaInAs HEMT's has been performed by using a semiclassical Monte Carlo simulation. The validity of the model has been checked through the comparison of the simulated results with static, dynamic and noise experimental measurements of real HEMTs. In order to reproduce the experimental results, we have included in the model some important real effects such as degeneracy, surface charges, T-shape of the gate, presence of dielectrics and contact resistances. Moreover, the extrinsic parameters of the devices have been added to the usual intrinsic small-signal equivalent circuit, thus allowing the calculation of the real noise of the HEMTs (characterized using the extrinsic minimum noise . In this way, we make possible not only the comparison with the experimental noise results, but also the analysis of the influence of the parasitic elements, the device width or the number of gate fingers on the noise of the HEMTs. The reliability of the simulator allows us to realize "computer experiments" which will make faster and cheaper the optimization process of the device design. for his work on the modeling and the characterization of MES-FETs and HEMTs. In 1977, he joined the Centre Hyperfrequences et Semiconducteurs, University of Lille, France. He is now Professor of electronics at the University of Lille. His main research interests are concerned with the modeling, the realization and the characterization of low noise devices for application in the centimeter and millimeter wave ranges.

The electrical properties of double perovskite Ho2NiTiO6 (HNT) are investigated by impedance spectroscopy in the temperature range 30–420 °C and frequency range 100 Hz to 1 MHz. The X-ray diffraction analysis reveals that the compound crystallizes in monoclinic phase. The imaginary part of impedance (Z″) as a function of frequency shows Debye type relaxation. The frequency dependence of Z″ peak is found to obey an Arrhenius law with an activation energy of 0.129 eV. Impedance data presented in the Nyquist plot (Z″ vs. Z′) are used to identify an equivalent circuit and to know the bulk and interface contributions. The complex impedance analysis of HNT exhibits the appearance of both the grain and grain-boundary contribution. The results of bulk ac conductivity as a function of temperature and frequency are presented. The activation energy (0.129 eV), calculated from the slope of log τ versus 103/T plot, is found to be the nearly same as calculated (0.130 eV) from dc conductivity. The frequency dependent conductivity spectra obey the power law.

We propose an equivalent circuit representation of the photogenerated charge separation and propagation in dye sensitized polycrystalline semiconductor in contact with a redox electrolyte. The suggested equivalent circuit for this type of photocell is based on an electrical transmission-line, and uses distributed photodiode model for the semiconductor-redox electrolyte interface. It was found that for small signal conditions, diodes can be replaced by equivalent elements, each consisting of a resistor and a capacitor connected in series. The equivalent circuit also provides for Beer-Lambert characteristics of light absorption. The simulation of the transmission line equivalent circuit, subjected to short pulse illumination, allows us to reproduce the experimentally found difference between the photocurrent responses of the photocell to illumination from the electrolyte side, and its response to illumination through the semitransparent back electrode, to which the polycrystalline sem...

A large-signal HJFET model is developed for drainlag phenomena caused by deep traps beneath the channel. The model is based on the self-backgating and Shockley-Read-Hall (SRH) statistics. It is shown by two-dimensional (2D) device simulation that electron capture in deep traps is much faster than electron emission under large-signal conditions; therefore, drain current exhibits different responses for rising and falling steps of applied voltage. In the circuit model, electron capture and emission in deep traps are expressed by a parallel circuit consisting of a diode and a resistor, which are physically deduced from SRH statistics. The model agrees well with the 2D simulation results and experimental current-transient data for large-signal voltage steps. In addition, this model accurately describes smallsignal drain-conductance dispersion and temperature effects on the trapping phenomena.

A simple non-quasi-static small-signal equivalent circuit model is derived for the ideal MOSFET wave equation under the gradual channel approximation. This equivalent circuit represents each Y-parameter by its DC small-signal value shunted by a (trans) capacitor in series with a charging (trans) resistor. A large-signal model for the intrinsic MOSFET is derived by first implementing this RC topology in the

This paper proposes a new differential topology that features a stacked multiloop inductor. Comparative studies of stacked one-to four-loop spiral inductors with and without patterned ground shields (PGSs) for silicon-based radio-frequency integrated circuits (RFICs) were conducted, and lumped-element circuit models were developed for these inductors. The partialelement equivalent-circuit method that can accurately analyze mutual inductive couplings among different spirals in these multiloop geometries was employed for capturing the frequencydependent inductances and resistances of inductors at low frequencies. A good agreement between numerical results and measurements is obtained. It is demonstrated that a stacked multiloop spiral inductor with differential topology and PGS has a larger inductance and a higher Q-factor as compared with the same inductor without differential topology and PGS. This hybrid methodology could provide a promising technique for developing new silicon-based passive devices used in RFICs.

A new modal decomposition equivalent circuit method has been proposed for an analysis of multifrequency and multi-layer frequency selective structure (FSS). The present paper is an extension of the previously published work where it has been shown that the method is valid for 'thin' and 'thick' FSS both for angles of incidence up to 608 and for any lattices and potentially allows the synthesis of FSS by the optimisation of circuit parameters. Further investigation has shown the methods validity for the analysis of complex FSS geometries. The method has been successfully applied for the analysis of double-ring slot FSS, 'A-sandwich' structures and so on. A very good agreement in comparison with the computational electromagnetic software and rigorous methods such as a periodic method of moments has been obtained.

A new topology for active power filters (APF) using an 81-level converter is analyzed. Each phase of the converter is composed of four three-state converters, all of them connected to the same capacitor dc link voltage and their output connected in series through output transformers. The main advantages of this kind of converter are the negligible harmonic distortion obtained and the very low switching frequency operation. The single-phase equivalent circuit is analyzed and their governing equations derived. The dc link voltage control, based on manipulating the converter's voltage phase, is analyzed together with the circuit's characteristics that determine the capability to draw or deliver active and reactive current. Simulation results for this application are compared with conventional pulsewidth-modulated (PWM) converters, showing that this filter can compensate load current harmonics, keeping better-quality sinusoidal currents from the source. The simulated configuration uses a 1-F ultracapacitor in the dc link, making it possible to store energy and deliver it during short voltage dips. This is achieved by applying a modulation control to maintain a stable ac voltage during dc voltage drops. A prototype of the filter was implemented and tested, and the obtained current waveforms showed to be as good as expected.

The electrochemical oxidation of bisphenol A was carried out using platinum, glassy carbon, titanium dioxide and polypyrrole modified working electrodes. Acetonitrile and water were evaluated as solvents; however, passivation could not be avoided due to the formation of insoluble oxidation products that adhere to the surface. The use of ultrasound did not show any improvement either. Finally, by using electrochemical impedance spectroscopy measurements at the open circuit potential it was possible to obtain a steady response of one of the components of the equivalent circuit proposed. This response is only dependent on the concentration of bisphenol A. At the same time it was demonstrated that the adsorption is a fundamental process that occurs more easily in water than in acetonitrile, this fact is reflected in the impedance spectra.

A novel optical technique is proposed for the characterization of MEMS resonators. The proposed technique is based on measuring the response of the resonator (resonance frequency and quality factor) optically, which eliminates the electrical parasitic effects. The proposed technique was applied to a comb-drive resonator and the obtained results show good agreement with the standard electrical technique with 2-5% deviation in the resonance frequency and 2-10% in the quality factor.

The behavior of excitable systems periodically stimulated by pulses is investigated. The nonself-oscillating regime is studied in the simplest realistic model. The global bifurcation structure is similar in several aspects to the one corresponding to driven oscillators. It includes phase locking, quasiperiodicity, period doubling, and chaos. The unexpected persistence of this structure is explained by analytical arguments and its scaling properties are numerically determined. Excitable systems are characterized by their behavior under external stimulation.

Measurements of real and imaginary parts of the relative complex permittivity of glycerol were carried out in the frequency range 1 mHz-1 MHz at different temperatures between 188 and 263 K. The permittivity data have been analyzed thoroughly by a new data curve-fitting approach that involves the so-called eigen-coordinates method in conjunction with a separation procedure and the inverse permittivity formulas. A new single permittivity function, based on the so-called recap element picture for a self-similar (fractal) structure, has been recognized to describe well such data over the entire frequency range studied. The recognized dielectric function enabled us to infer an electrical equivalent-circuit network for the glycerol sample studied that involves a series combination of two recap elements, reflecting the existence of two different dielectric relaxation processes in glycerol. The temperature dependence of the relaxation times s 1 ðT Þ and s 2 ðT Þ entering into the identified permittivity function was found to obey nearly an Arrhenius behaviour with activation energies E 1 % 114 kJ/mol and E 2 % 94 kJ/mol. The recognized permittivity function can be justified by presuming that the processes represented by the recap elements characterized by the parameters (m 1 , s 1 , E 1) and (m 2 , s 2 , E 2) are linked to 'donor-like' and 'acceptor-like' charges formed from the infinite hydroxyl hydrogen bonds.

Many different circuit models have been proposed for double-layer capacitors (DLCs). Presented in this paper is an evaluation of the Debye polarization cell as a model for a double-layer capacitor (DLC). In comparison to other circuit models, the primary advantage of this model is that the circuit elements can be related to chemical reactions which occur inside the DLC. The circuit element values are found from ac impedance measurements for a DLC and a computer program which utilizes a nonlinear least-squares fitting technique. Variations in circuit element values with dc bias level and manufacturing have been investigated. The performance of the Debye polarization cell in slow discharge and pulse load applications has been compared to actual circuit measurements and to simulated results using a classical equivalent circuit.

The paper deals with analytical method of design and prediction of performance characteristics for induction motors with solid steel rotor coated with copper layer. On the basis of the distribution of the 2-D electromagnetic field, the equivalent impedance of the rotor has been derived. The edge effect and nonlinear magnetic permeability of solid steel have been included. The presented analytical method has been verified with laboratory test results. A 300 kW, 60 000-rpm, three-phase solid-rotor induction motor for the next generation air compressor has been investigated. The accuracy of analytical approach is acceptable and can be recommended for rapid design of solid-rotor induction motors.

The objective of this work was to develop a SPICE compatible equivalent circuit of a thermoelectric module (TEM). A methodology is developed for extracting the parameters of the proposed model from manufacturers' data of Thermoelectric Coolers (TEC) and Thermoelectric Generators (TEG). The model could be helpful for analyzing the drive requirements of TECs and loading effects of TEGs. The present model is compatible with PSPICE or other electric circuit simulators. An important feature of the model is its ability to generate small signal transfer functions that can be used to design feedback networks for temperature control applications.

Based on an active transmission line concept and twodimensional (2-D) device simulations, an accurate and computationally efficient simulation technique for high frequency noise performance of MOSFETs is demonstrated. Using a Langevin stochastic source term model and small-signal equivalent circuit of the MOSFET, three intrinsic noise parameters ( , , and ) for the drain noise and induced gate noise are calculated. Validity and error analysis for the simulation are discussed by comparing the simulation results with theoretical results as well as measured data.

Sandia has been studying the performance of a group of 18650-size lithium-ion cells fabricated for the Advanced Technology Development (ATD) Program that contain high-power battery chemistry. One of the objectives of the ATD Program is to develop procedures to make rapid comparisons of performance degradation rates and predictions of battery life. This paper will discuss a simple lithium-ion battery modeling approach, which uses an equivalent circuit model (ECM) as the basis to simulate the lithium-ion cell performance, particularly the capacity fade phenomenon.

In this paper, a novel type of auxiliary switched which may consist of planer (pancake) or cylindrical type capacitor assisted edge resonant soft switching PWM series load working coil with electromagnetic eddy current based heated resonant high frequency inverter with two auxiliary edge materials. Consumer IH appliances operating at high resonant lossless inductor snubbers is proposed for small frequency ranges from 20 kHz to several MHz need a cost consumer induction heating appliances. The operation principle of this high frequency inverter is described using the switching effective product, high efficiency and high power density of mode equivalent circuits. This newly developed multi resonant high frequency inverters. Among various types of the high high frequency inverter using trench gate lGBTs can regulate its frequency inverter topologies, there are full bridge, half high frequency output AC power under a principle of constant bridge, single-ended push-pull (SEPP), centre tap push-pull frequency edge-resonant soft switching commutation by and boost-half bridge circuit configurations, in which voltage asymmetrical PWM control scheme. The high frequency power source type lossless snubber inductor assisted zero current regulation and actual power conversion efficiency characteristics soft switching (ZCS) SEPP series load resonant topologies, of consumer brand-new IH products that use the proposed soft voltage source type zero voltage soft switching (ZVS) SEPP switching PWM series load resonant high frequency inverter are resonant inverter and voltage source ZVZCS-SEEP multi evaluated. The practical effectiveness and operating resonant inverter topologies [4]-[8]. These high frequency soft performances of the newly proposed soft switching inverter are song inverter s have The high f soft discussed as compared with the conventional soft switching high switching inverterS have the advantages of simple frequency inverters based on simulation and experimental results configuration, high efficiency, low cost and wide soft from an application point of view.

The electrochemical behavior of Cu–Ni alloys with different Ni contents (5–65mass%) in acidic sulfate solutions was investigated. The effects of working conditions e.g. concentration of sulfate ions, immersion time and temperature were studied and discussed. In this respect, open-circuit potential measurements, polarization techniques and electrochemical impedance spectroscopy (EIS) were used. Potentiodynamic measurements revealed that the increase in the Ni content

Nanoelectrospray technique, or electrohydrodynamic spraying, has been utilised in wide applications including mass spectrometry, microcolloid thrusters and micro/nano-fabrication areas. In this article, a nanoelectrospray system was developed in a pure voltage-controlled fashion with low flow rates of nL/min. Electrospray occurs by applying a voltage to overcome surface tension of the liquid without auxiliary backpressure. Pronounced increase of current with applied voltage was revealed during the pressure-free spray. In the steady spray regime a linear correlation between current and voltage was clearly identified; this can be attributed directly to the unforced electrospray where the spray properties are uniquely dictated by the voltage. This behaviour may be captured by an equivalent circuit method based upon empirical results. The equivalent circuit resistance, derived from the best-fit model, represents an electrical equivalence of the gap between the nozzle and the collector; this resistance strongly depends on both the nozzle size and the spray distance. The suitability of an electrical equivalent is further confirmed by incorporating a series resistor. No obvious difference can be distinguished electrically between a resistor and the resistance of the gap, suggesting that unforced spray can be adjusted and stabilised externally by using the series resistor method.

Electrical impedance spectroscopy was used for the characterization of electroregeneration in a continuous electrodeionization (CEDI) system packed with cation-exchange resin (CIX). CEDI process usually operates in two regimes of enhanced transfer and electroregeneration. The current efficiency decreased in the second regime of a CEDI system due to the water dissociation. Therefore, it is necessary to minimize the second regime to maximize the current efficiency by controlling the operating parameters even though the second regime is essential for regeneration of the resin. It was suggested to monitor the ionic state of the bed during the operation by observing current distribution along the column. The measurement of the resistance of CIX beads at high frequency, based on the equivalent circuit, provided information on the extent of electrical regeneration of the bed. The optimal current density was estimated at the minimized area of second regime, and the operation at the optimal current density showed the 100% of metal removal, indicating the effectiveness of this method.

This paper deals with conducted Electromagnetic Interference (EMI) produced by power electronic converters. Both differential-and common-mode components of the conducted emissions are considered. In particular, the analysis is focused on converters controlled with PWM techniques and supplied by a DC source. A circuit model which takes account of parasitic components is proposed for a switching cell that is the basic structure of this kind of converters. The values of the parasitic parameters (inductances and capacitances) are obtained by measurements, field analysis or both. This model permits the influence of the different parasitic parameters to be investigated. The simulations carried out by PSpice are compared with the corresponding experimental data obtained from a DC chopper prototype. The good agreement between the numerical and experimental results proves that the proposed equivalent circuit allows the prediction of the main conducted EM1 phenomena with sufficient accuracy.

This paper presents the evaluation of the performance, in terms of uncertainty, of a tool designed to estimate the main parameters of a model of a photovoltaic panel (PVP) under real and/or simulated working conditions. The presented tool permits the characterization of the panel, and it is useful to predict its behavior in whatever working condition; in this way, it is possible to compare the actual and expected performance to prevent any decrease in the output power, so permitting the replacement of the monitored module before it goes out of order or its efficiency falls under a given threshold. The well-known two-diode model is used to estimate the parameters of the electrical equivalent circuit of the PVP and to simulate the I -V and P-V characteristic curves in any given environmental condition of irradiance and/or temperature. The model and the estimation algorithm are implemented with MATLAB functions, whereas data acquisition and result presentation are managed by a LabVIEW graphics user interface. The presented tool has been validated against an experimentally characterized PVP. The environmental parameters of the model such as irradiance and temperature have been set (with their respective uncertainties) during simulations or directly measured during the outdoor tests, whereas the others parameters have been evaluated using a best-fit algorithm on the measured data. The estimation is based on the minimization of a new objective function and on a modified expression of the model resistances, which differ from those mentioned in the available literature. After a review of the state of the art, this paper provides the description of the estimation technique and its validation by means of simulations and experiments. Some results are also provided to illustrate the performance of the proposed test method.

We present a study of impedance spectroscopy (IS) under varying loads. An equivalent circuit is proposed taking the deformability and the effect of change in free volume into account, which yields the dc ion-conductivity as well as the Young's modulus from these results. Independent measurements of elastic properties are done and the result is compared with Young's modulus predicted from IS. The sample we studied is PEO-NH 4 ClO 4 with a salt fraction of 0.19 by weight, with frequencies varying in the range of 40 Hz to 3 MHz and loads varying from 400 to 1600 g.

Photodetectors (PDs) are an important active device in optoelectronic integrated circuits (OEICs), and, for shorter haul interconnections where circuit (e.g. transimpedance amplifier (TIA)) noise may be the dominant noise in receivers, metal-semiconductor-metal photodiodes (MSM PDs) are attractive due to their low capacitance per unit area compared to PIN photodetectors and the ease of monolithic integration with field effect transistors (FETs). Inverted-MSM PDs (I-MSM PDs), which are thin film MSM PDs with the fingers on the bottom of the device, have demonstrated higher responsivities compared to conventional MSM PDs while maintaining small capacitance per unit area, low dark current (~nA), and high speed. However, the modeling of MSM PDs and I-MSM PDs for insertion into circuit simulators for integrated PD/TIA modeling has not been reported. In this paper, an accurate highfrequency equivalent circuit-level model of thin film I-MSM PDs is obtained using an on-wafer measurement-based modeling technique. This circuit-level model of MSM PDs can be used for capacitance sensitive preamplifier design for co-optimization with widely used simulators (ADS and HSPICE). The obtained circuit-level model shows good agreement with measured s-parameters.

Recent work by Klippel [1] and Voishvillo [2] has shown the significance of voice coil inductance in respect to the non-linear behaviour of loudspeakers. In such work the methods used to derive distortion require the inductance to be represented by an equivalent circuit rather than the frequency domain models of Wright and Leach. A new technique for measurement of displacement and frequency dependant impedance has been introduced. The complex relationship between coil impedance, frequency and displacement has been both measured and modelled, using FE, with exceptional agreement. Results show that the impedance model requires that its parameters vary independently with x to satisfactorily describe all cases. Distortion induced by the variation of impedance with coil displacement is predicted using both parameterised and FE methods, these predictions are compared to measurements of the actual distortion. The nature of this distortion is discussed.

This paper deals with contact currents that may occur when the human body is in contact with two electrodes at different electrical potentials, e.g., an electrical/electronic device and the floor. Actually, any device must comply not only with electromagnetic compatibility and safety requirements, but also with specific electromagnetic field exposure recommendations in order to prevent health hazards for the occupational and general public population. Since the contact currents depend on the applied voltage and on the human body impedance, this last parameter has been measured for several configurations in a broadband frequency range, from 40 Hz to 110 MHz. From the measurement results, a new equivalent circuit of the human body impedance is derived by using a vector-fitting procedure. This equivalent circuit is very easy and can be adopted for compliance tests against contact currents. Index Terms-Bioelectric phenomena, contact currents, electromagnetic field (EMF) exposure, human body impedance, safety standards. I. INTRODUCTION T HE hazards to humans due to exposure to electromagnetic fields (EMF) have been well studied and documented [1], [2]. Proven or short-term adverse health effects refer mainly to the heating of the exposed regions at high-frequency radiations [3], [4], and to the circulation of induced currents inside regions exposed at low-frequency electric or magnetic fields [5], [6]. Another important effect of low-frequency exposures is represented by contact currents occurring when a person touches conductive surfaces at different potential and becomes a path for the current flow through the body [7]. Existing exposure standards, e.g., International Council on Nonionizing Radiation Protection (ICNIRP), IEEE C95.6-2002, and IEEE C95.1-2005 [8]-[10], present guidelines and rules to prevent the exposure of humans to EMFs. These safety standards provide recommendations or limits in terms of basic

Power transformer analysis and design focusing on the equivalent circuit parameter evaluation by magnetic field numerical calculation is presented. The proposed method adopts a particular reduced scalar potential formulation enabling 3D magnetostatic problem solution. This method, necessitating no source field calculation, in conjunction with a mixed finite element-boundary element technique, results in a very efficient 3D numerical model for power transformer design office use. Computed results are validated through measurements. Such a methodology is very promising for investigation concerning losses and short circuit voltage variations with the main geometrical parameters.

The increasing demand for more fuel efficiency and environmentally friendly cars coupled with the consumers' drive for more comfort, safety and luxury has led to the introduction of more electrical and electronic systems in the passenger car. This is further impacted by the current trend in automotive industry to replace mechanical and hydraulic systems with their electrical counterparts. The handling

This presentation continues the study of the dynamic characteristics of lead-acid batteries previously reported into larger cells and batteries. Electrochemical impedance spectroscopy combined with fuzzy logic methodology of data analysis was used to characterize 6 V 10 Ah VRLA batteries and larger batteries used in tanks and other vehicles. Equivalent circuits were derived which can be used to estimate state-of-charge (SOC) and state-of-health. #

A new equivalent circuit for inverters is presented. Using this circuit, expression for the elements of the coupling matrix of narrow RF band pass filters is derived. The derivation is based on frequency independent coupling assumed in the synthesis of narrow RF band pass filters. Our expression is different from an earlier expression obtained using lumped circuit representations of different types of coupling and their analysis. It is shown that the earlier expression can be derived from our analysis if the coupling is assumed frequency-variant. Unlike earlier work, our derivation shows how the sign of the coupling coefficient can be obtained. © 2009 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2010.

This paper presents a neural network based approach for improving the accuracy of the electrical equivalent circuit of a photovoltaic module. The equivalent circuit parameters of a PV module mainly depend on solar irradiation and temperature. The dependence on environmental factors of the circuit parameters is investigated by using a set of current-voltage curves. It is shown that the relationship between them is nonlinear and cannot be easily expressed by any analytical equation. Therefore, the neural network is utilized to overcome these difficulties. The neural network is trained once by using some measured current-voltage curves, and the equivalent circuit parameters are estimated by only reading the samples of solar irradiation and temperature very quickly without solving any nonlinear implicit equations that is necessary in conventional methods. To verify the proposed model, an experimental set up is installed. The comparison between the measured values and the proposed model results shows higher accuracy than the conventional model for all operating conditions.

The characteristics of a buck type three phase PWM rectifier are analyzed using circuit DQ transform method. Exact DQ equivalent circuit model is induced and full set of equations are derived in explicit form. With the signal flow graph to describe the internal relations of converter operation, the unique behavior of the converter is analyzed on several practical view points. Various converter characteristics such as gain,real and reactive power,power factor and unity power factor condition including the effects of component values and load variations are analyzed as a function of modulation index and PWM phase angle variation. 0-7803-2730-6/95 $4.00 0 1995 IEEE 431

A knowtedge of the average electrical impedance of the human body is essentiat for the anafysis of electromagnetic harards in the VLF to MF band. The purpose of our measurements was to determine the average body impedance of severaf human subjects as a function of frequency. Measurements were carried out with the snbjects standing barefoot on a ground plane and touching various metaf electrodes with the hand or index finger. The measured impedance includes the electrode polarization and skin impedances, spread impedance near the electrode, body impedance, stray capacitance between the body surface and ground, and inductance due to the body and grounding strap. 'fhese components are separated and simplifkd equivalent circuits are presented for body impedance of humans exposed to free-space electromagnetic waves as well as in contact with large ungrounded metaltic objects therein.

The b Ti-29Nb-13Ta-4.6Zr (TNTZ) has been recently developed as a new implant material. TNTZ alloy is composed of non toxic elements and has a low modulus of elasticity than the other titanium alloys. However, its electrochemical behaviour has not yet been studied. Hence in the present work, the influence of potential on electrochemical behaviour of TNTZ alloy under simulated physiological condition was investigated by electrochemical impedance spectroscopy (EIS). The experimental results were compared with those obtained for titanium (Cp-Ti). All measurements were obtained in aerated Hank's solution at 37°C and at different potentials E corr , 0 mV (SCE), 500 mV (SCE) and 1000 mV (SCE). The EIS behaviour of the TNTZ alloy is unique in nature compared to Cp-Ti, exhibiting two-time constants indicating the formation two layers only at higher potentials.

Schmitt trigger design with given circuit thresholds is described. The approach is based on studying the transient from one stable state to another when the trigger is in linear operation. The trigger is subdivided into two subcircuits; each of them is considered as a passive load for the other. This allows the relations governing the deviations of the circuit thresholds from their given values to be obtained. The trigger device sizes are thus determined by the threshold tolerances.

Simultaneous measurements of conductive polymer by two-and four-point techniques were used for evaluation of the contact resistance for the polymer/metal interface. An experimental validation of this approach was performed for polypyrrole electrochemically deposited on gold electrodes. The dependence of contact resistance on the electrode potential versus reference electrode was measured. The results were compared with the corresponding dependence obtained from impedance spectroscopy. Both techniques provide almost identical data while the new approach is easier, faster and independent on selection of equivalent circuits.

The Drude-Lorentz model is a well-known method used to estimate the permittivity of a material, describing its atoms as oscillating dipoles. Notwithstanding its simplicity, in many contexts that model is quite effective and so today it's widely used. In this paper we are going to present a circuit model analogous to the Drude-Lorentz one and formally governed by the same harmonic equation. In order to better describe the atomic dipole, we also introduce the concept of half-capacitor, i.e. a circuit element allowing to accumulate net charge on a node. The resulting circuit is quite simple but easy to be extended in 3D and to multi-orbital atoms. However, it is primarily intended to be a powerful project tool for microscopic structures in the field of metamaterials.

Translation of English proverbs into Persian language makes Iranian translators encounter at the Source Language (SL) comparing Target Language (TL) levels such as lexical, stylistic, cultural and rhetorical parameters. In this respect, the main concerns would be on the three corresponding SL/TL bases: form, content and context. This goes back to similar and different parameters of English and Persian languages regarding Contrastive Analysis studies in the 1940s. At the content and context levels, there may be several shared properties between SL and TL equivalents which are connotatively motivated while at the formal level the lexical differences can be problematic. This survey provides a model which facilitates the translation of English proverbs into Persian with the minimum loss in the connotative meaning of the SL proverbs. It also proposes a theoretical model concerned with weak, moderate and strong versions of conceptual translation equivalents. This model is applicable in th...