Magnetics modeling for computer-aided design of power electronics circuits
Sayed-Amr El-Hamamsy; Eric I. Chang
1989-01-01
Existing models of magnetic components in simulators fail to describe magnetic components in a physically correct manner. The reluctance model includes geometric information and gives accurate results for the energy. An electric-to-magnetic circuit interface is derived that allows the direct inclusion of the reluctance model in the simulation. The energy in the magnetics is accurately described by use of the
A model for coupled magnetic-electric circuits in electric machines with skewed slots
F. Piriou; A. Razek
1990-01-01
A model permitting the simulation of skewed-slot saturated machines associated with nonlinear external circuits is proposed. To take the slot effects into account, the magnetic circuit is modeled through the combined two-dimensional calculations along the machine axis. In this simulation the electric circuit equation is directly coupled with the magnetic one. The solution of the resulting nonlinear time-dependent equation is
Magnetic equivalent circuit modeling of induction machines under stator and rotor fault conditions
Gennadi Y. Sizov; Chia-Chou Yeh; Nabeel A. O. Demerdash
2009-01-01
In this paper, stator and rotor failures in squirrel-cage induction machines are modeled using the magnetic equivalent circuit (MEC) approach. Failures associated with stator winding and rotor cage are considered. More specifically, stator inter-turn short circuit and broken rotor bar failures are modeled. When compared to conventional modeling techniques, the MEC modeling approach offers two main advantages: 1) relatively high
A coupling between electric circuits and 2D magnetic field modeling
A. Nicolet; F. Delince; N. Bamps; A. Genon; W. Legros
1993-01-01
A method which enables coupling between equations of electric circuits consisting of a lumped element RLC configuration and a magnetic field model is presented. The coupling between the finite-element and the boundary-element methods is used to compute the magnetic field produced by conductors excited by an electric circuit. The conductors involved in this computation may be connected according to any
12. DEVICES AND APPLICATIONS Abstract --This paper presents a magnetic circuit modeling of
Paris-Sud XI, Université de
loop Hall-effect current sensors based on a magnetic equivalent circuit which could be simulated Hall-effect current sensors is presented, Then, the magnetic equivalent circuit (MEC) modeling The closed loop Hall-effect current sensors [1] can measure all kinds of current from DC to several tens of k
Modeling Magnetic Radiations of Electronic Circuits Using Near-Field Scanning Method
Yolanda Vives-Gilabert; Christian Arcambal; Anne Louis; Francois de Daran; Philippe Eudeline; Blahcne Mazari
2007-01-01
In this paper, a simple method to obtain the equivalent radiation emitting sources of an electronic circuit using the near-field scanning method is presented. The model is based on a set of elemental dipoles that substitutes the electronic circuit and radiates the same magnetic field. Two different approaches are presented: a set of electric dipoles and a set of magnetic
A non-linear coupled 3D model for magnetic field and electric circuit equations
F. Piriou; A. Razek
1992-01-01
The authors propose a 3-D numerical model in which the magnetic field and electric circuit equations in the absence of eddy currents are solved simultaneously. To consider the magnetic equations, use is made of a magnetic vector potential formulation with the gauge condition (A.w=0) which makes it possible to reduce the number of unknowns. To take into account the magnetic
Amin Mahyob; Mohamed Y. Ould Elmoctar; Pascal Reghem; Georges Barakat
2008-01-01
The aim of this paper is to present and compare two modeling methods of the inter-turn short circuit fault in the stator winding of a cage induction machine. The first method is a Coupled Magnetic Circuit Method (CMCM) and the second method is a Permeance Network Method (PNM) which allows taking into account the saturation effect on the fault signature.
Magnetic Circuit Model of PM Motor-Generator to Predict Radial Forces
NASA Technical Reports Server (NTRS)
McLallin, Kerry (Technical Monitor); Kascak, Peter E.; Dever, Timothy P.; Jansen, Ralph H.
2004-01-01
A magnetic circuit model is developed for a PM motor for flywheel applications. A sample motor is designed and modeled. Motor configuration and selection of materials is discussed, and the choice of winding configuration is described. A magnetic circuit model is described, which includes the stator back iron, rotor yoke, permanent magnets, air gaps and the stator teeth. Iterative solution of this model yields flux linkages, back EMF, torque, power, and radial force at the rotor caused by eccentricity. Calculated radial forces are then used to determine motor negative stiffness.
Magnetic switches and circuits
Nunnally, W.C.
1982-05-01
This report outlines the use of saturable inductors as switches in lumped-element, magnetic-pulse compression circuits is discussed and the characteristic use of each is defined. In addition, the geometric constraints and magnetic pulse compression circuits used in short-pulse, low-inductance systems are considered. The scaling of presaturation leakage currents, magnetic energy losses, and switching times with geometrical and material parameters are developed to aid in evaluating magnetic pulse compression systems in a particular application. Finally, a scheme for increasing the couping coefficient in saturable stripline transformers is proposed to enable their use in the short-pulse, high-voltage regime.
NSDL National Science Digital Library
VU Bioengineering RET Program,
Students use the same method as in the activity from lesson 2 of this unit to explore the magnetism due to electric current instead of a permanent magnet. Students use a compass and circuit to trace the magnetic field lines induced by the electric current moving through the wire. Students develop an understanding of the effect of the electrical current on the compass needle through the induced magnetic field and understand the complexity of a three dimensional field system.
A Magnetic Circuit Demonstration.
ERIC Educational Resources Information Center
Vanderkooy, John; Lowe, June
1995-01-01
Presents a demonstration designed to illustrate Faraday's, Ampere's, and Lenz's laws and to reinforce the concepts through the analysis of a two-loop magnetic circuit. Can be made dramatic and challenging for sophisticated students but is suitable for an introductory course in electricity and magnetism. (JRH)
Seok-Hee Han; T. M. Jahns; W. L. Soong
2007-01-01
A new magnetic circuit model is presented for an interior permanent magnet (IPM) synchronous machine, using a machine with three-phase distributed stator windings and three layers of flux barriers in the rotor as an example topology. The model accounts for: i) the effects of cross-coupled magnetic saturation caused by the salient rotor; ii) variation of magnetic saturation levels in the
Research of Equivalent Circuit Model of Magnetic Component in Magnetic Integration Technology
Wang Zhong
Equivalen t circuit models of ma gnetic compon en t ar e s ummarized a nd a n ew model is proposed, whe re t he s tru ctur e of magn etic compone nt is reflected and t h e circ uit a nalysis is car ried ou t fle xibly. T he relationship figures of four k inds
Surface polaritons in magnetic metamaterials from perspective of effective-medium and circuit models
NASA Astrophysics Data System (ADS)
Hadjicosti, K.; Sydoruk, O.; Maier, S. A.; Shamonina, E.
2015-04-01
Surface waves are responsible for many phenomena occurring in metamaterials and have been studied extensively. At the same time, the effects of inter-element coupling on surface electromagnetic waves (polaritons) remain poorly understood. Using two models, one relying on the effective-medium approximation and the other on equivalent circuits, we studied theoretically surface polaritons propagating along an interface between air and a magnetic metamaterial. The metamaterial comprised split rings that could be uncoupled or coupled to each other in the longitudinal or transverse directions (along or perpendicular to the propagation direction). A metamaterial without inter-element coupling supported a single polariton. When a moderate longitudinal coupling was included, it changed the wave dispersion only quantitatively, and the results of the effective-medium and the circuit models were shown to agree at low wavenumbers. However, the presence of a transverse coupling changed the polariton dispersion dramatically. The effective-medium model yielded two branches of polariton dispersion at low values of the transverse coupling. As the coupling increased, both polaritons disappeared. The validity of the effective-medium model was further tested by employing the circuit model. In this model, surface polaritons could exist in the presence of a transverse coupling only if the boundary layer of the metamaterial included additional impedances, which could become non-Foster. The results reveal that the inter-element coupling is a major mechanism affecting the properties of the polaritons. They also highlight the limitations of using bulk effective-medium parameters for interface problems in metamaterials.
A Differential Magnetic Circuit for Teaching Purposes
ERIC Educational Resources Information Center
Kraftmakher, Yaakov
2010-01-01
A differential magnetic circuit (magnetic bridge) is described. The circuit separates the magnetic field sensor and the sample under study. A Hall probe serves as the sensor. The signal from the sensor can be enhanced by concentrating the magnetic flux. The magnetic bridge works even with dc magnetic fields. The device is used for displaying…
Magnetodiode equivalent circuits for simulation of magnetic field sensors
NASA Astrophysics Data System (ADS)
Hotra, Zenon; Holyaka, Roman; Hladun, Michael
2003-09-01
The models for magnetic field sensors in SPICE software for circuit simulation are considered in this paper. The new approach for synthesis of magnetodiode equivalent circuits is presented. It is shown that using combination of physical and empirical models it is possible to maintain effective analysis of sensors in specialized software for circuit simulation.
Simulation of magnetic component models in electric circuits including dynamic thermal effects
Peter R. Wilson; J. Neil Ross; Andrew D. Brown
2002-01-01
It is essential in the simulation of power electronics applications to model magnetic components accurately. In addition to modeling the nonlinear hysteresis behavior, eddy currents and winding losses must be included to provide a realistic model. In practice the losses in magnetic components give rise to significant temperature increases which can lead to major changes in the component behavior. In
Jiaxin Chen; Youguang Guo; Jianguo Zhu
2007-01-01
This paper presents the comprehensive performance evaluation of a brushless permanent magnet (PM) DC (BLDC) motor in dynamic conditions by an improved phase variable model based on electro-magnetic field coupled with its external circuits. In the proposed model, the inductances, back electromotive force (emf) and cogging torque are obtained by nonlinear finite element analysis (FEA). The phase variable model is
NASA Astrophysics Data System (ADS)
Cui, Xiao-Le; Zhou, Hao-Miao
2015-07-01
The nonlinear thermo–magneto–mechanical magnetostrictive constitutive and the linear thermo–mechanical-electric piezoelectric constitutive are adopted in this paper. The bias magnetic field and ambient temperature are equivalent to a magnetic source and a thermo source, respectively. An equivalent circuit, which contains a magnetic source and a thermo source at the input, for the thermo–magneto–electric coupling effect in magnetoelectric (ME) laminates, is established. The theoretical models of the output voltage and static ME coefficient for ME laminates can be derived from this equivalent circuit model. The predicted static ME coefficient versus temperature curves are in excellent agreement with the experimental data available both qualitatively and quantitatively. It confirms the validity of the proposed model. Then the models are adopted to predict variations in the output voltages and ME coefficients in the laminates under different ambient temperatures, bias magnetic fields, and the volume ratios of magnetostrictive phases. This shows that the output voltage increases with both increasing temperature and increasing volume ratio of magnetostrictive phases; the ME coefficient decreases with increasing temperature; the ME coefficient shows an initial sharp increase and then decreases slowly with the increase in the bias magnetic field, and there is an optimum volume ratio of magnetostrictive phases that maximize the ME coefficient. This paper can not only provide a new idea for the study of the thermo–magneto–electric coupling characteristics of ME laminates, but also provide a theoretical basis for the design and application of ME laminates, operating under different sensors. Project supported by the National Natural Science Foundation of China (Grant Nos. 11172285 and 11472259) and the Natural Science Foundation of Zhejiang Province, China (Grant No. LR13A020002).
Electronic circuit reliability modeling
Joseph B. Bernstein; Moshe Gurfinkel; Xiaojun Li; Jörg Walters; Yoram Shapira; Michael Talmor
2006-01-01
Abstract The intrinsic failure mechanisms,and reliability models,of state-of-the-art MOSFETs are reviewed. The simulation tools and failure equivalent circuits are described. The review includes historical background,as well as a new,approach,for accurately predicting circuit reliability and failure rate from,the system,point of view. ? 2006 Elsevier Ltd. All rights reserved.
Modeling of transformers using circuit simulators
NASA Astrophysics Data System (ADS)
Archer, W. E.; Deveney, M. F.; Nagel, R. L.
Transformers of two different designs, an unencapsulated pot core and an encapsulated toroidal core, have been modeled for circuit analysis with circuit simulation tools. We selected MicroSim's PSPICE and Anology's SABER as the simulation tools and used experimental BH Loop and network analyzer measurements to generate the needed input data. The models are compared for accuracy and convergence using the circuit simulators. Results are presented which demonstrate the effects on circuit performance from magnetic core losses, eddy currents, and mechanical stress on the magnetic cores.
NASA Astrophysics Data System (ADS)
Seo, Jung-Moo; Jung, In-Soung; Jung, Hyun-Kyo; Ro, Jong-Suk
2014-05-01
A simple and rapid analysis and design method is proposed for a coreless permanent magnet machine (CPMM) using a hexagonal winding (HW). The HW, which combines a rectangular winding (RTW) and rhombic winding (RBW), can compensate for the disadvantages and maximize the advantages of the RTW and RBW. The CPMM is typically analyzed using complex differential equations or a timeconsuming finite element analysis (FEA). To address this problem, a relatively simpler and less timeconsuming analysis method is proposed by using a lumped equivalent magnetic circuit (LEMC) model. Furthermore, an effect of winding angle on a motor performance is analyzed via precise inspection of the relationship between the variables of the HW and the characteristics of motor. The validity and usefulness of the proposed method are verified via FEA and experiment.
Magnetic switches and circuits, revision 2
NASA Astrophysics Data System (ADS)
Nunnally, W. C.
1984-05-01
The use of saturable inductors as switches in lumped-element, magnetic-pulse compression circuits is outlined. The operation of the three basic types of magnetic pulse compression circuits is discussed and the characteristic use of each is defined. In addition, the geometric constraints and magnetic pulse compression circuits used in short-pulse, low-inductance systems are considered. The scaling of presaturation leakage currents, magnetic energy losses, and switching times with geometrical and material parameters are developed to aid in evaluating magnetic pulse compression systems in a particular application. Finally, a scheme for increasing the coupling coefficient in saturable stripline transformers is proposed to enable their use in the short-pulse, high-voltage regime.
Bin Li; Gui-Dan Li; Hong-Feng Li
2011-01-01
The paper studies the magnetic field distribution of three degree-of-freedom (3-DOF) permanent magnet (PM) spherical motor adopting the 3-D magnetic equivalent circuits (MEC) method. Compared with the analytical method and finite element analysis (FEA) method, the MEC has such desirable attributes as moderate computational effort and reasonable accuracy. The model of PM spherical motor is evenly meshed into elements in
Magnetic circuit for hall effect plasma accelerator
NASA Technical Reports Server (NTRS)
Manzella, David H. (Inventor); Jacobson, David T. (Inventor); Jankovsky, Robert S. (Inventor); Hofer, Richard (Inventor); Peterson, Peter (Inventor)
2009-01-01
A Hall effect plasma accelerator includes inner and outer electromagnets, circumferentially surrounding the inner electromagnet along a thruster centerline axis and separated therefrom, inner and outer magnetic conductors, in physical connection with their respective inner and outer electromagnets, with the inner magnetic conductor having a mostly circular shape and the outer magnetic conductor having a mostly annular shape, a discharge chamber, located between the inner and outer magnetic conductors, a magnetically conducting back plate, in magnetic contact with the inner and outer magnetic conductors, and a combined anode electrode/gaseous propellant distributor, located at a bottom portion of the discharge chamber. The inner and outer electromagnets, the inner and outer magnetic conductors and the magnetically conducting back plate form a magnetic circuit that produces a magnetic field that is largely axial and radially symmetric with respect to the thruster centerline.
Inductance model for coupling finite element analysis with circuit Simulation
Sami Kanerva; Slavomir Seman; Antero Arkkio
2005-01-01
This paper presents a method for coupling magnetic field equations of the electrical machine with circuit equations of the windings and external electric circuits. The electrical machine is modeled by the electromotive force and the dynamic inductance, which are determined by finite element method (FEM) and updated at each time step in transient simulation. The external circuit model is simulated
Rohrer, Brandon Robinson; Rothganger, Fredrick H.; Verzi, Stephen J.; Xavier, Patrick Gordon
2010-09-01
The neocortex is perhaps the highest region of the human brain, where audio and visual perception takes place along with many important cognitive functions. An important research goal is to describe the mechanisms implemented by the neocortex. There is an apparent regularity in the structure of the neocortex [Brodmann 1909, Mountcastle 1957] which may help simplify this task. The work reported here addresses the problem of how to describe the putative repeated units ('cortical circuits') in a manner that is easily understood and manipulated, with the long-term goal of developing a mathematical and algorithmic description of their function. The approach is to reduce each algorithm to an enhanced perceptron-like structure and describe its computation using difference equations. We organize this algorithmic processing into larger structures based on physiological observations, and implement key modeling concepts in software which runs on parallel computing hardware.
Didactic Considerations on Magnetic Circuits Excited by Permanent Magnets
ERIC Educational Resources Information Center
Barmada, S.; Rizzo, R.; Sani, L.
2009-01-01
In this paper, the authors focus their attention on the way magnetic circuits and permanent magnets are usually treated in most textbooks and electrical engineering courses. This paper demonstrates how this important topic is too often presented simplistically. This simplistic treatment does not allow the students to develop a complete…
Nonlinear varying-network magnetic circuit analysis for doubly salient permanent-magnet motors
Ming Cheng; K. T. Chau; C. C. Chan; E. Zhou; X. Huang
2000-01-01
In this paper, a nonlinear varying-network magnetic circuit (VNMC) modeling method is developed for doubly salient permanent-magnet (DSPM) motors. The method is used to analyze the static characteristics of DSPM motors by specific performance calculations, in which the interaction between the permanent-magnet field and the armature current field, as well as magnetic saturation, are taken into account. Two newly proposed
Reconfigurable Circuits Using Magnetic Tunneling Junction Memories
Victor Silva; Jorge R. Fernandes; Horácio C. Neto
2010-01-01
\\u000a This paper presents the first results of our work to research and develop new reconfigurable circuits and topologies based\\u000a on Magnetic RAM (MRAM) memory elements. This work proposes a coarse-grained reconfigurable array using MRAM. A coarse-grained\\u000a array, where each reconfigurable element computes on 4-bit or larger input words, is more suitable to execute data-oriented\\u000a algorithms and is more able to
R. A. Salas; J. Pleite; E. Olías; A. Barrado
2008-01-01
The aim of this article is to present a theoretical–experimental comparison of the voltage and current waveforms of an inductor which is included in a buck DC–DC converter at a switching frequency of 100kHz. Theoretical voltage and current waveforms are obtained applying a modeling procedure for magnetic components based on finite element analysis (FEA). Such procedure takes into account the
Semiconductor Circuit Diagnostics By Magnetic Field Imaging
NASA Astrophysics Data System (ADS)
Venkatesan, T.
2011-03-01
At the forefront of IC technology development are 3D circuit technologies such as system-in-package (SiP), wafer-level-packaging (WLP), through-silicon-vias (TSV), stacked die approaches, flex packages, etc. They integrate multiple devices, many times stacking them in layers with complex, intricate and very long interconnections in significantly reduced area, in addition to an ever-increasing number of opaque layers.~ We could very well say that the near future looks like the perfect nightmare for the Failure Analysis (FA) engineer with localization of defects becoming a major challenge. Magnetic field imaging (MFI) allows the fields generated by the circuit currents to go through various packaging layers and be imaged. I will describe in this talk Magma, a scanning magnetic field imaging system based on a high temperature superconducting SQUID device based on YBa2Cu3O7- ? . The HTS SQUIDs used have a noise level of ~ 20 pT/ ? (Hz) and for typical scanning conditions, a field sensitivity of about 0.7 nT. While current shorts are imaged with spatial resolution, up to 3 micron (with peak localization) resistive opens can also be imaged and currently different strategies are being adapted for imaging opens with large working distances of 50-100s of microns. Higher spatial resolution (~ 250 nm) is obtained by the use of magneto-resistive devices as sensors though the working distance requirement is sever
Magnetic force microscopy method and apparatus to detect and image currents in integrated circuits
Campbell, A.N.; Anderson, R.E.; Cole, E.I. Jr.
1995-11-07
A magnetic force microscopy method and improved magnetic tip for detecting and quantifying internal magnetic fields resulting from current of integrated circuits are disclosed. Detection of the current is used for failure analysis, design verification, and model validation. The interaction of the current on the integrated chip with a magnetic field can be detected using a cantilevered magnetic tip. Enhanced sensitivity for both ac and dc current and voltage detection is achieved with voltage by an ac coupling or a heterodyne technique. The techniques can be used to extract information from analog circuits. 17 figs.
Magnetic force microscopy method and apparatus to detect and image currents in integrated circuits
Campbell, Ann. N. (13170-B Central SE #188, Albuquerque, NM 87123); Anderson, Richard E. (2800 Tennessee NE, Albuquerque, NM 87110); Cole, Jr., Edward I. (2116 White Cloud NE, Albuquerque, NM 87112)
1995-01-01
A magnetic force microscopy method and improved magnetic tip for detecting and quantifying internal magnetic fields resulting from current of integrated circuits. Detection of the current is used for failure analysis, design verification, and model validation. The interaction of the current on the integrated chip with a magnetic field can be detected using a cantilevered magnetic tip. Enhanced sensitivity for both ac and dc current and voltage detection is achieved with voltage by an ac coupling or a heterodyne technique. The techniques can be used to extract information from analog circuits.
TIMING MODELS FOR MOS CIRCUITS
Mark Alan Horowitz
1984-01-01
Performance is an important aspect of integrated circuit design, and dependsin part on the speed of the underlying circuits. This thesis presents a new methodof analyzing MOS circuit delay, based on a single-time-constant approximation.
Computing with Neural Circuits: A Model
John J. Hopfield; David W. Tank
1986-01-01
A new conceptual framework and a minimization principle together provide an understanding of computation in model neural circuits. The circuits consist of nonlinear graded-response model neurons organized into networks with effectively symmetric synaptic connections. The neurons represent an approximation to biological neurons in which a simplified set of important computational properties is retained. Complex circuits solving problems similar to those
Domain structure and magnetic losses in laminated magnetic circuits upon laser treatment
NASA Astrophysics Data System (ADS)
Pudov, V. I.; Dragoshanskii, Yu. N.
2015-06-01
Methods of optimizing the magnetic domain structure and functional characteristics of electrical-sheet anisotropic steel based on the Fe-Si alloy and the laminated magnetic circuits of transformers have been developed. The use of an efficient complex based on the local laser treatment and application of magnetically active electrically insulating coatings provided a significant reduction in the magnetic losses in the sheets of the steel (by 18-22%) and in the magnetic circuits of transformers (by 9-14%).
Review on Magnetic Components: Design & Consideration in VHF Circuit Applications
Nor Zaihar Yahaya; Mumtaj Begam Kassim Raethar; Mohammad Awan
2009-01-01
When converters operate in megahertz range, the passive components and magnetic devices generate high losses. However, the eddy current issues and choices of magnetic cores significantly affect on the design stage. Apart from that, the components' reduction, miniaturization technique and frequency scaling are required as well as improvement in thermal capability, integration technique, circuit topologies and PCB layout optimization. In
Use of magnetic materials in excimer laser circuits
Vannini, M.; Sze, R.; Hommeau, F.
1987-01-01
The use of saturating magnetic materials in laser excitation discharge systems is presented. Particular attention is given to the most important parameters of magnetic materials and to the analysis of some circuits such as single and multi-stage pulse compressor and pre-pulse isolation systems. 25 refs.,5 figs.
A nonlinear circuit model for IMPATT diodes
J. Gannett; L. Chua
1978-01-01
An improved nonlinear circuit model for IMPATT diodes is presented for which each element bears a simple relationship with the physical operating mechanisms inside the device. The model contains lumped nonlinear elements as well as lumped and distributed linear elements. In its most general form it incorporates various second-order effects heretofore neglected in other circuit models. These include the effects
Equivalent Circuit Modeling of Hysteresis Motors
Nitao, J J; Scharlemann, E T; Kirkendall, B A
2009-08-31
We performed a literature review and found that many equivalent circuit models of hysteresis motors in use today are incorrect. The model by Miyairi and Kataoka (1965) is the correct one. We extended the model by transforming it to quadrature coordinates, amenable to circuit or digital simulation. 'Hunting' is an oscillatory phenomenon often observed in hysteresis motors. While several works have attempted to model the phenomenon with some partial success, we present a new complete model that predicts hunting from first principles.
Semiconductor switched capacitive circuit for energy transfer between superconducting magnets
Baker, J.R.; Walters, J.D. [Naval Surface Warfare Center, Annapolis, MD (United States)
1994-12-31
A solid-state IGBT switched capacitive circuit capable of transferring energy between two 0.94 henry NbTi superconducting magnets storing 5.0 kJ has been developed. Maximum operating current in the magnets and switching circuit is 100A. Energy transfer between magnets is step-wise requiring the coupling capacitor to store only a small fraction of a magnet`s total stored energy. Energy transfer time is directly proportional to magnet current and inductance, and is inversely proportional to the maximum voltage across the coupling capacitor. Initial energy transfer rate goal is 5.0 kW; equating to a time rate of change in the magnetic field of 1.7 Tesla/sec. Only a small power supply is required to provide the initial charge to one coil, replace dissipated energy due to resistive heating in the semiconductor switches and connecting cables, and A.C. losses in the superconducting magnets. Test results from operating this energy transfer circuit are presented and discussed.
Qian, Junbing; Chen, Xuedong; Chen, Han; Zeng, Lizhan; Li, Xiaoqing
2013-01-01
A simple and accurate method based on the magnetic equivalent circuit (MEC) model is proposed in this paper to predict magnetic flux density (MFD) distribution of the air-gap in a Lorentz motor (LM). In conventional MEC methods, the permanent magnet (PM) is treated as one common source and all branches of MEC are coupled together to become a MEC network. In our proposed method, every PM flux source is divided into three sub-sections (the outer, the middle and the inner). Thus, the MEC of LM is divided correspondingly into three independent sub-loops. As the size of the middle sub-MEC is small enough, it can be treated as an ideal MEC and solved accurately. Combining with decoupled analysis of outer and inner MECs, MFD distribution in the air-gap can be approximated by a quadratic curve, and the complex calculation of reluctances in MECs can be avoided. The segmented magnetic equivalent circuit (SMEC) method is used to analyze a LM, and its effectiveness is demonstrated by comparison with FEA, conventional MEC and experimental results. PMID:23358368
Quantum computation beyond the circuit model
Jordan, Stephen Paul
2008-01-01
The quantum circuit model is the most widely used model of quantum computation. It provides both a framework for formulating quantum algorithms and an architecture for the physical construction of quantum computers. However, ...
Electric vehicle charger with printed circuit board magnetic components
C. P. Henze
2000-01-01
An 800 Watt portable battery charger for electric vehicles is built using a single four-layer printed circuit board for interconnection all of the power components and to form the magnetic component windings which comprise the EMI filter, a high power factor boost rectifier and a series resonant inverter. Low profile planar E-cores are inserted through slots in the PCB to
Vacuum discharge driven by a magnetic pulse compression circuit
R. Presura; N. Georgescu; M. Cengher; V. Zoita
1996-01-01
Low pressure discharges in a compact coaxial geometry were produced by applying either positive or negative high voltage pulses delivered by a three-stage magnetic pulse compression circuit. The driver provided repetitive pulses of up to 15 kV and 20 J maximum transferred energy per pulse. The inner electrode was a rod having either a pointed or flat end with sharp
Analysis of magnetic proportional drive circuits for bipolar junction transistors
R. L. Avant; W. T. Michael; D. J. Shortt; R. E. Palma
1985-01-01
A comparison is presented of some advantages and disadvantages of three popular magnetic proportional drive circuits for bipolar junction transistors (BJT) used in spacecraft switched mode power supplies (SMPS). A generic classification of these drives is introduced. A novel adaptation of one of these drives, the multiple mode proportional drive (MMPD), is developed to provide a total proportional drive for
Terminal modeling of hardened integrated circuits
NASA Astrophysics Data System (ADS)
Kleiner, C. T.; Haas, R.; Peacock, M.; Mandel, G.; Messenger, G. C.; Weakley, D.; Demartino, V.
1981-12-01
Kleiner et al. (1979) have reported modeling and test verification techniques used to develop medium-scale, dielectrically isolated integrated circuits (DIIC). The current investigation is concerned with the approaches employed in modeling the new circuits for applications studied by design and radiation hardening engineers. The described technique improves significantly the cost-effective application of computer programs such as SYSCAP II. The terminal model offers the designer of radiation-hardened electronic circuits a method for evaluating the effects of radiation transients on single or multiple piece-part response at the circuit board level. Although the models presented were intended for TREE design and analysis, it is possible to extend the technique to EMP and SGEMP evaluations.
Multiple coupled circuit modeling of induction machines
Xiaogang Luo; Yuefeng Liao; H. A. Toliyat; A. El-Antably; T.A. Lipo
1995-01-01
A new multiple coupled circuit model is presented for simulation of induction machines with both arbitrary winding layout and\\/or unbalanced operating conditions. The model is derived by means of winding functions. No symmetry is assumed. The parameters of the model are calculated directly from the geometry and winding layout of the machine. The behavior of an induction machine during starting
High bandwidth magnetically isolated signal transmission circuit
NASA Technical Reports Server (NTRS)
Repp, John Donald (Inventor)
2005-01-01
Many current electronic systems incorporate expensive or sensitive electrical components. Because electrical energy is often generated or transmitted at high voltages, the power supplies to these electronic systems must be carefully designed. Power supply design must ensure that the electrical system being supplied with power is not exposed to excessive voltages or currents. In order to isolate power supplies from electrical equipment, many methods have been employed. These methods typically involve control systems or signal transfer methods. However, these methods are not always suitable because of their drawbacks. The present invention relates to transmitting information across an interface. More specifically, the present invention provides an apparatus for transmitting both AC and DC information across a high bandwidth magnetic interface with low distortion.
Equivalent Circuit Modeling of Piezoelectric Energy Harvesters
Yaowen Yang; Lihua Tang
2009-01-01
Last decade has seen growing research interest in vibration energy harvesting using piezoelectric materials. When developing piezoelectric energy harvesting systems, it is advantageous to establish certain analytical or numerical model to predict the system performance. In the last few years, researchers from mechanical engineering established distributed models for energy harvester but simplified the energy harvesting circuit in the analytical derivation.
Introductory Invited Paper Electronic circuit reliability modeling
Shapira, Yoram
Introductory Invited Paper Electronic circuit reliability modeling Joseph B. Bernstein *, Moshe and prediction. This paper reviews the existing modeling and prediction methods and presents an approach for accu of the relatively complex electronic equipment 0026-2714/$ - see front matter Ó 2006 Elsevier Ltd. All rights
NASA Astrophysics Data System (ADS)
Prabhu Gaunkar, N.; Bouda, N. R. Y.; Nlebedim, I. C.; Hadimani, R. L.; Bulu, I.; Ganesan, K.; Song, Y. Q.; Mina, M.; Jiles, D. C.
2015-05-01
This work presents investigations and detailed analysis of ringing in a non-resonant pulsed nuclear magnetic resonance (NMR) circuit. Ringing is a commonly observed phenomenon in high power switching circuits. The oscillations described as ringing impede measurements in pulsed NMR systems. It is therefore desirable that those oscillations decay fast. It is often assumed that one of the causes behind ringing is the role of the magnetic core used in the antenna (acting as an inductive load). We will demonstrate that an LRC subcircuit is also set-up due to the inductive load and needs to be considered due to its parasitic effects. It is observed that the parasitics associated with the inductive load become important at certain frequencies. The output response can be related to the response of an under-damped circuit and to the magnetic core material. This research work demonstrates and discusses ways of controlling ringing by considering interrelationships between different contributing factors.
Wideband circuit model for busbar impedance
Mark Jones; Arthur W. Kelley
2000-01-01
The series R-L equivalent circuit model, often used to represent laminated busbar impedance in time-domain simulations, cannot provide accurate results because the effective AC laminated busbar resistance and inductance depend on frequency. Using the series R-L model yields incorrect predictions of damping and losses that occur at high frequencies. This paper shows that a Cauer network model, developed for microwave
Bjt Modeling for Circuit Simulation
Clement Keung Szeto
1995-01-01
Physical models for transport mechanisms important in bipolar transistors are developed, implemented in SPICE3 for DC, AC, and transient analyses, and assessed with numerical device simulations. The analytical model of quasi-saturation, or base -push-out, is derived for all current levels. Deficiencies in previous quasi-saturation models are revealed and overcome. The quasi-saturation model is based on a derivation of the current-induced-base
Pekka Ikonen; Sergei Tretyakov
2006-01-01
The equivalent circuit model for artificial magnetic materials based on\\u000avarious arrangements of split rings is generalized by taking into account\\u000alosses in the substrate or matrix material. It is shown that a modification is\\u000aneeded to the known macroscopic permeability function in order to correctly\\u000adescribe these materials. Depending on the dominating loss mechanism\\u000a(conductive losses in metal parts
W. Q. Chu; Z. Q. Zhu
2011-01-01
This paper aims to find effective methods to avoid irreversible demagnetisation in permanent magnet machines by suppressing the short-circuit current. An analytical model is developed to predict the transient currents, overcoming the problems of previous steady state models which may significantly underestimate the short-circuit current. Although the developed analytical model is simple, it can accurately reveal the relationship between the
Jung, I.S.; Hur, J.; Hyun, D.S.
1999-09-01
Permanent magnet linear synchronous motors (PMLSM's) are proposed for many applications ranging from ground transportation to servo system and conveyance system. In this paper, the fields and forces of permanent magnet linear synchronous motor (PMLSM) with segmented or skewed magnet arrangement are analyzed according to length of segment or skew. And, the effects according to the lateral overhang of magnet are investigated. For the analysis, 3-dimensional equivalent magnetic circuit network (3-D EMCN) method is used. The analysis results are compared with the experimental ones and shown a reasonable agreement.
Probabilistic Graphical Models for the Diagnosis of Analog Electrical Circuits
Borgelt, Christian
Probabilistic Graphical Models for the Diagnosis of Analog Electrical Circuits Christian Borgelt electrical circuit. This model can be used to do probabilis- tic diagnosis based on manufacturer supplied approaches to the diagnosis of electrical circuits have been developed [10, 11]. Examples are: the fault
Probabilistic Graphical Models for the Diagnosis of Analog Electrical Circuits
Borgelt, Christian
Probabilistic Graphical Models for the Diagnosis of Analog Electrical Circuits Christian Borgelt electrical circuit. This model can be used to do probabilis tic diagnosis based on manufacturer supplied approaches to the diagnosis of electrical circuits have been developed [10, 11]. Examples are: the fault
Modeling aspects of magnetic actuators and magnetic suspension systems
NASA Astrophysics Data System (ADS)
Bloodgood, Vernon Dale, Jr.
This dissertation is a study of new modeling techniques developed for magnetic suspension systems. The techniques discussed are modifications of magnetic circuit theory and fundamental eddy current models. The techniques are compared against experimental test results and finite element data. The information gained from the experimental testing is used to provide insight into magnetic bearing design. A small-gap modeling technique called extended circuit theory is developed that incorporates information about the system gained from finite element data, or experimental data, to be included in the analytic model. The variations between the classical magnetic circuit model and the finite element model are used to develop performance coefficients, which are in turn incorporated into the extended circuit model. The coefficients modify the classical theory to account for magnetomotive force losses, flux leakage and flux fringing. The theory is developed from fundamental principles. The techniques used to determine, and predict, the coefficients are discussed. The use of this method in optimal bearing design is also discussed. The extended circuit model is verified against experimental test results of a family of magnetic actuators. The actuators consist of a "C-shaped" stator and a flat armature. The pole separation distance was varied along with the location of the biasing permanent magnets and the windings. The permanent magnets were placed either on the pole faces, in the center of the armature, or at both locations, and the windings were wound on poles of the stator or on the back of the stator, resulting in a total of 22 design permutations. The experimental performance of each design is analyzed and efficiency trends are discussed. The diffusive model for eddy currents is analyzed along with the lumped parameter model to explore the "half-order" behavior of eddy currents commonly observed in experimental testing. A fractional order eddy current model is developed and compared against finite element data and experimental test results. The models developed are based on a frequency dependent resistance. The implications of using fractional order modeling techniques, along with control considerations, are discussed.
Gamma and Theta Rhythms in Biophysical Models of Hippocampal Circuits
Pervouchine, Dmitri D.
. Pervouchine, P. Malerba, and A. Tort Introduction The neural circuits of the hippocampus are extremely complexGamma and Theta Rhythms in Biophysical Models of Hippocampal Circuits N. Kopell, C. B¨orgers, D
Noise analysis of a current-mode read circuit for sensing magnetic tunnel junction resistance
Michael J. Hall; Viktor Gruev; Roger D. Chamberlain
2011-01-01
Magneto logic circuits are digital logic circuits con structed using magnetic tunnel junction (MTJ) devices. These devices are non-volatile, robust, and scale favorably with process dimensions. Several approaches exist for building magnetologic circuits. We are investigating current-mode magnetologic cir cuits as a viable option. Current-mode circuits avoid charg ing\\/discharging load capacitances and can be used to program a downstream device.
The Design of a RapidDischarge Varistor System for the MICE Magnet Circuits
Green, Michael A.
2008-07-23
The need for a magnet circuit discharge system, in order to protect the magnet HTS leads during a power failure, has been discussed in recent MICE reports [1], [2]. In order to rapidly discharge a magnet, one has to put enough resistance across the lead. The resistance in this case is varistor that is put across the magnet in the event of a power outage. The resistance consists of several diodes, which act as constant voltage resistors and the resistance of the cables connecting the magnets in the circuit to each other and to the power supply. In order for the rapid discharge system to work without quenching the magnets, the voltage across the magnets must be low enough so that the diodes in the quench protection circuit don't fire and cause the magnet current to bypass the superconducting coils. It is proposed that six rapid discharge varistors be installed across the three magnet circuits the power the tracker solenoids, which are connected in series. The focusing magnets, which are also connected in series would have three varistors (one for each magnet). The coupling magnets would have a varistor for each magnet. The peak voltage that is allowed per varistor depends on the number of quench protection diodes that make up the quench protection circuit for each magnet coil circuit. It is proposed that the varistors be water cooled as the magnet circuits are being discharged through them. The water cooling circuit can be supplied with tap water. The tap water flows only when the varistor temperature reaches a temperature of 45 C.
Computation of magnetic suspension of maglev systems using dynamic circuit theory
He, J.L.; Rote, D.M.; Coffey, H.T.
1991-01-01
Dynamic circuit theory is applied to several magnetic suspensions associated with maglev systems. These suspension systems are the loop-shaped coil guideway, the figure-eight-shaped null-flux coil guideway, and the continuous sheet guideway. Mathematical models, which can be used for the development of computer codes, are provided for each of these suspension systems. The differences and similarities of the models in using dynamic circuit theory are discussed in the paper. The paper emphasizes the transient and dynamic analysis and computer simulation of maglev systems. In general, the method discussed here can be applied to many electrodynamic suspension system design concepts. It is also suited for the computation of the performance of maglev propulsion systems. Numerical examples are presented in the paper. 15 refs., 7 figs., 1 tab.
Computation of magnetic suspension of maglev systems using dynamic circuit theory
NASA Technical Reports Server (NTRS)
He, J. L.; Rote, D. M.; Coffey, H. T.
1992-01-01
Dynamic circuit theory is applied to several magnetic suspensions associated with maglev systems. These suspension systems are the loop-shaped coil guideway, the figure-eight-shaped null-flux coil guideway, and the continuous sheet guideway. Mathematical models, which can be used for the development of computer codes, are provided for each of these suspension systems. The differences and similarities of the models in using dynamic circuit theory are discussed in the paper. The paper emphasizes the transient and dynamic analysis and computer simulation of maglev systems. In general, the method discussed here can be applied to many electrodynamic suspension system design concepts. It is also suited for the computation of the performance of maglev propulsion systems. Numerical examples are presented in the paper.
Equivalent circuit models for ac impedance data analysis
NASA Technical Reports Server (NTRS)
Danford, M. D.
1990-01-01
A least-squares fitting routine has been developed for the analysis of ac impedance data. It has been determined that the checking of the derived equations for a particular circuit with a commercially available electronics circuit program is essential. As a result of the investigation described, three equivalent circuit models were selected for use in the analysis of ac impedance data.
Pekka M. T. Ikonen; Sergei A. Tretyakov
2007-01-01
The equivalent-circuit model for artificial magnetic materials based on various arrangements of broken loops is generalized by taking into account losses in the substrate or matrix material. It is shown that a modification is needed to the known macroscopic permeability function in order to correctly describe these materials. Depending on the dominating loss mechanism (conductive losses in metal parts or
Electrical circuit model of arrays of resonant elements
NASA Astrophysics Data System (ADS)
Lomanets, V.; Zhuromskyy, O.; Onishchukov, G.; Peschel, U.
2012-03-01
We present an effective electrical circuit model that can be used for a quasianalytic analysis of electromagnetic oscillations in arrays of coupled elements, resonant in the microwave domain. The model accounts for electric and magnetic interactions between charges and currents excited in individual resonators. Respective coupling coefficients can be calculated from the field and current distributions in a subsystem of just one or two elements, provided by a finite-difference electromagnetic solver. The model was used to investigate current distributions and dispersion relations of wave propagation on chains of coupled split-ring resonators. The change of the dispersion characteristics from forward to backward propagating wave type observed experimentally is readily reproduced by the model.
Combination of thermal subsystems modeled by rapid circuit transformation
Y. C. Gerstenmaier; W. Kiffe; G. Wachutka
2007-01-01
This paper will deal with the modeling-problem of combining thermal subsystems (e.g. a semiconductor module or package with a cooling radiator) making use of reduced models. The subsystem models consist of a set of Foster-type thermal equivalent circuits, which are only behavioral models. A fast algorithm is presented for transforming the Foster-type circuits in Cauer-circuits which have physical behavior and
Model Reduction for a Class of Nonlinear Electrical Circuits
Reis, Timo
Model Reduction for a Class of Nonlinear Electrical Circuits by Reduction of Linear Subcircuits: electrical circuits, passive systems, model reduction, modified nodal analysis 1. Introduction Model for key technologies" http://www.matheon.de #12;Model Reduction for a Class of Nonlinear Electrical
Generic linear RC delay modeling for digital CMOS circuits
An-chang Deng; Yan-chyuan Shiau
1990-01-01
The linear RC delay modeling technique is used to model the timing delays in CMOS circuit empirically. The empirical model, a multidimensional function of various circuit and device parameters, is shown to be simplified to a two-dimensional model which estimates the delay of a CMOS subcircuit in terms of the generic RC delay ad the rise\\/fall time of the input
Influence of Model of Circuit-breaker on Very Fast Transient Over-voltage
NASA Astrophysics Data System (ADS)
Na, Wang; Yu, Liang
Based on a power station, two transient models of circuit-breaker is employed and the very fast transient over-voltage in 550kVGIS is calculated and simulated in the consideration of two different models of circuit-breaker, applying the Electro-Magnetic Transient Program in this paper. The impact of varied models on the values and the frequencies of VFTO in the GIS is intensively focused. It is indicated that the two models of circuit breaker have different effects on the peak voltage of VFTO for different nodes. Under the two operation modes, the deviations of the most voltage spectrum frequency are 5.8% and 0 at circuit breaker. Comparing to the results of the two operation modes, the deviation of operating DS21 are higher than that of operating DS22 because of the changing current flow.
A Testing Approach for MOS Circuit Using Single-Photon Detectors Under High Magnetic Fields
NASA Astrophysics Data System (ADS)
Pan, Zhongliang; Chen, Ling; Chen, Junfang; Zhang, Guangzhao; Wu, Peiheng
2013-03-01
The MOS circuits must be tested thoroughly for insuring the reliability. A new testing approach for MOS circuits is presented in this paper, which makes use of single-photon detectors and high magnetic fields. If there are faults in the circuit under test, the photon emission from the circuit components is detected by a single-photon detector, the faults are located by the amount of the emitted photons. The following two techniques are proposed in this paper. First, the high magnetic field is applied to the circuit under test, i.e., the circuit is put in high magnetic field environment. To some extent this technique can solve the problem that some faults have poor strengths of emitted photons under general environment. Second, the special circuit input vectors are designed by using binary decision diagrams. The input vectors can make the positions of circuit components to produce signal transitions or switching behaviors, therefore the photon emission strengths of circuit components are enhanced. A lot of experimental results show that the faults in MOS circuits can be tested accurately by the approach proposed in this paper.
An improved solar cell circuit model for organic solar cells
B. Mazhari
2006-01-01
The validity of conventional circuit model for interpreting results obtained using organic solar cells is examined. It is shown that the central assumption in the model that photo-generated current remains constant from short-circuit to open-circuit condition may not hold for organic cells. An improved model based on the photovoltaic response of organic solar cells is proposed and a method of
ERIC Educational Resources Information Center
Fay, T. H.; Mead, L.
2006-01-01
The paper discusses an elementary spring model representing the motion of a magnet suspended from the ceiling at one end of a vertical spring which is held directly above a second magnet fixed on the floor. There are two cases depending upon the north-south pole orientation of the two magnets. The attraction or repelling force induced by the…
Yield learning model for integrated circuit package
Balasubramaniam, Gaurishankar
1996-01-01
In a semiconductor industry, packaging of integrated circuit chips, product quality control and rapid problem diagnosis are very critical to economic success. The integrated circuit package makes up a large fraction of the total production cost...
CMOS Interface Circuits for Spin Tunneling Junction Based Magnetic Random Access Memories
Ganesh Saripalli
2002-12-31
Magneto resistive memories (MRAM) are non-volatile memories which use magnetic instead of electrical structures to store data. These memories, apart from being non-volatile, offer a possibility to achieve densities better than DRAMs and speeds faster than SRAMs. MRAMs could potentially replace all computer memory RAM technologies in use today, leading to future applications like instan-on computers and longer battery life for pervasive devices. Such rapid development was made possible due to the recent discovery of large magnetoresistance in Spin tunneling junction devices. Spin tunneling junctions (STJ) are composite structures consisting of a thin insulating layer sandwiched between two magnetic layers. This thesis research is targeted towards these spin tunneling junction based Magnetic memories. In any memory, some kind of an interface circuit is needed to read the logic states. In this thesis, four such circuits are proposed and designed for Magnetic memories (MRAM). These circuits interface to the Spin tunneling junctions and act as sense amplifiers to read their magnetic states. The physical structure and functional characteristics of these circuits are discussed in this thesis. Mismatch effects on the circuits and proper design techniques are also presented. To demonstrate the functionality of these interface structures, test circuits were designed and fabricated in TSMC 0.35{micro} CMOS process. Also circuits to characterize the process mismatches were fabricated and tested. These results were then used in Matlab programs to aid in design process and to predict interface circuit's yields.
Limitations of inductive circuit model representations of meander line antennas
S. R. Best; J. D. Morrow
2003-01-01
The resonant frequency of meander line antennas can be predicted using an equivalent inductor circuit model representation. As a function of increasing number of meander sections, these models provide a reasonable approximation of the relative change in resonant frequency. Some limitations of these inductor circuit model representations are examined for different meander line antennas having a fixed number of meander
Design and application of thin, planar magnetic components for embedded passives integrated circuits
Etierhard Waffenschmidt
2004-01-01
The integration of passive components into the printed circuit board (PCB) as embedded passives integrated circuits (emPIC) results in a higher power density of power converters. To achieve a highly automated, low cost, integral manufacturing, the devices are constructed layerwise. Especially for magnetic components like inductors and transformers the design of such thin components is challenge. Because of the high
Statistical Model Order Reduction for Interconnect Circuits Considering Spatial Correlations
Fan, Jeffrey
Statistical Model Order Reduction for Interconnect Circuits Considering Spatial Correlations University, Beijing, 100084, China ABSTRACT In this paper, we propose a novel statistical model order reduction technique, called statistical spectrum model order reduction (SS- MOR) method, which considers
Quantum Computation Beyond the Circuit Model
Stephen P. Jordan
2008-09-13
The quantum circuit model is the most widely used model of quantum computation. It provides both a framework for formulating quantum algorithms and an architecture for the physical construction of quantum computers. However, several other models of quantum computation exist which provide useful alternative frameworks for both discovering new quantum algorithms and devising new physical implementations of quantum computers. In this thesis, I first present necessary background material for a general physics audience and discuss existing models of quantum computation. Then, I present three results relating to various models of quantum computation: a scheme for improving the intrinsic fault tolerance of adiabatic quantum computers using quantum error detecting codes, a proof that a certain problem of estimating Jones polynomials is complete for the one clean qubit complexity class, and a generalization of perturbative gadgets which allows k-body interactions to be directly simulated using 2-body interactions. Lastly, I discuss general principles regarding quantum computation that I learned in the course of my research, and using these principles I propose directions for future research.
Characteristics and Circuit Model of a Field Emission Triode
Jung Hyun Nam; Jeong Don Ihm; Hyung Soo Uh; Yeo Hwan Kim; Kyu Man Choi; Jong Duk Lee
1997-01-01
* Abstract - A circuit model for a jeld emission triode has been proposed. The model parameters have been extractedfiom the fabricated silicon tip array and verijied by comparing with the results simulated by circuit simulator (SPICE). The cut-oflfiequency can be calculated Pom the parametric capacitance and the transconductance values extracted. For the Jield emission triode, the capacitance of 3.45
Modeling and optimization of complex photonic resonant cavity circuits
Michael Sumetsky; Benjamin J. Eggleton
2003-01-01
The simple method for modeling of circuits of weakly coupled lossy resonant cavities, previously developed in quantum mechanics, is generalized to enable calculation of the transmission and reflection amplitudes and group delay of light. Our result is the generalized Breit-Wigner formula, which has a clear physical meaning and is convenient for fast modeling and optimization of complex resonant cavity circuits
Short-Circuit Modeling of a Wind Power Plant: Preprint
Muljadi, E.; Gevorgian, V.
2011-03-01
This paper investigates the short-circuit behavior of a WPP for different types of wind turbines. The short-circuit behavior will be presented. Both the simplified models and detailed models are used in the simulations and both symmetrical faults and unsymmetrical faults are discussed.
Field analysis and enhancement of multi-pole magnetic components fabricated on printed circuit board
NASA Astrophysics Data System (ADS)
Chiu, Kuo-Chi; Chen, Chin-Sen
2007-09-01
A multi-pole magnetic component magnetized with a fine magnetic pole pitch of less than 1 mm is very difficult to achieve by using traditional methods. Moreover, it requires a precise mechanical process and a complicated magnetization system. Different fine magnetic pole pitches of 300, 350 and 400 ?m have been accomplished on 9-pole magnetic components through the printed circuit board (PCB) manufacturing technology. Additionally, another fine magnetic pole pitch of 500 ?m was also fabricated on a dual-layered (DL) wire circuit structure to investigate the field enhancement. After measurements, a gain factor of 1.37 was obtained in the field strength. The field variations among different magnetic pole pitches were analyzed in this paper.
Vahid Abbasi; Ahmad Gholami; Kaveh Niayesh
2012-01-01
A 3-D transient model has been developed to investigate plasma current deformation driven by internal and external magnetic fields and their influences on arc stability in a circuit breaker. The 3-D distribution of electric current density is obtained by solving the current continuity equation along with the generalized Ohm's law in the presence of an external magnetic field, while a
Bali, R.
1986-07-01
The object of this paper is to investigate the behavior of the magnetic field in a cosmological model for perfect fluid distribution. The magnetic field is due to an electric current produced along the /chi/ axis. It is assumed that expansion (/theta/) in the model is proportional to sigma/sup 1//sub 1/, the eigenvalue of the shear tensor sigma /sup j/ /sub i/. The behavior of the model when the magnetic field tends to zero and other physical properties are also discussed.
Computer models of hearing aid transducers for integrated circuit design.
Agnew, J
1992-03-01
Electronic circuit modeling using computer-based simulation tools is well established and device models are available for common electronic components. However, acoustic models of audio transducers for use during integrated circuit design are not readily available. This causes difficulty for designers of audio amplifiers, and increases the uncertainties of a successful silicon integration of a circuit design. This paper reports on a technique for the creation of electroacoustic models of hearing aid microphones and receivers that can be connected to an amplifier under design, and incorporated into PSPICE simulations. Verification of the technique and models was performed by comparing measured frequency response data with graphs created by PSPICE modeling. The conclusions were that the method developed for creating these models, and the models themselves, were accurate enough to be used for acoustic simulations of frequency response performance during amplifier design, and gave results comparable to data obtained from breadboard measurements of the same circuits. PMID:1564209
A Wide Bandwidth Model for the Electrical Impedance of Magnetic BearingS
NASA Technical Reports Server (NTRS)
Meeker, David C.; Maslen, Eric H.; Noh, Myounggyu D.
1996-01-01
Magnetic bearings are often designed using magnetic circuit theory. When these bearings are built, however, effects not included in the usual circuit theory formulation have a significant influence on bearing performance. Two significant sources of error in the circuit theory approach are the neglect of leakage and fringing effects and the neglect of eddy current effects. This work formulates an augmented circuit model in which eddy current and flux leakage and fringing effects are included. Through the use of this model, eddy current power losses and actuator bandwidth can be derived. Electrical impedance predictions from the model are found to be in good agreement with experimental data from a typical magnetic bearing.
A discussion of yield modeling with defect clustering, circuit repair, and circuit redundancy
T. L. Michalka; R. C. Varshney; J. D. Meindl
1990-01-01
The mathematical foundation of common integrated--circuit yield models based on the assumption that the yield is dominated by random point defects is discussed. Various mathematical models which are commonly used to account for defect clustering are given a physical interpretation and are compared mathematically and graphically. A yield model applicable when the repair of some defects in a chip is
E Colin Cherry
1949-01-01
When making calculations on a circuit, containing both electric impedances and transformers, it is frequently desirable to consider the transformers removed and the constraints they impose replaced by a rearrangement of the impedances connected to their terminals. Such \\
Noise Source Lumped Circuit Modeling and Identification for Power Converters
Jin Meng; Weiming Ma; Qijun Pan; Zhihua Zhao; Lei Zhang
2006-01-01
In this paper, a general lumped circuit modeling method is proposed to describe the conducted electromagnetic interference (EMI) coupling mechanism for the switching power converters. The EMI characteristics of the converters can be analytically deduced from a circuit theoretical viewpoint. The shunt and series impedance insertion method is introduced to identify the differential-mode (DM) and common-mode (CM) noise impedances and
Calibration of nonlinear magnetic flow meters in the sodium circuits of fast power reactors
L. A. Adamovskii; V. V. Golovanov; Yu. N. Inkin; E. P. Kozubov
1987-01-01
The authors construct a calibration formulation and procedure for a permanent-magnet-based flow meter which incorporates such parameters as temperature, the electric conductivity of the sodium and the pipe material, the dimensions of the cooling circuit being monitored, the magnetic Reynolds number, and nonlinear eddy current distortions.
From the Biot-Savart Law to Ampere's Magnetic Circuital Law via Synthetic Differential Geometry
Hirokazu Nishimura
2014-01-31
It is well known in classical electrodynamics that the magnetic field given by a current loop and the electric field caused by the corresponding dipoles in sheets are very similar, as far as we are far away from the loop, which enables us to deduce Ampere's magnetic circuital law from the Biot-Savart law easily. The principal objective in this paper is to show that synthetic differential geometry, in which nilpotent infinitesimals are in abundance, furnishes out a natural framework for the exquisite formulation and its demonstration. This similitude in heaven enables us to transit from the Biot-Savart law to Ampere's magnetic circuital law like a shot on earth.
Parameterized modeling of multiport passive circuit blocks
Mahmood, Zohaib
2010-01-01
System level design optimization has recently started drawing the attention of circuit designers. A system level optimizer would search over the entire design space, adjusting the parameters of interest, for optimal ...
Transformation of quantum photonic circuit models by term rewriting
Gopal Sarma; Ryan Hamerly; Nikolas Tezak; Dmitri S. Pavlichin; Hideo Mabuchi
2012-06-06
The development of practical methods for synthesis and verification of complex photonic circuits presents a grand challenge for the nascent field of quantum engineering. Of course, classical electrical engineering provides essential foundations and serves to illustrate the degree of sophistication that can be achieved in automated circuit design. In this paper we explore the utility of term rewriting approaches to the transformation of quantum circuit models, specifically applying rewrite rules for both reduction/verification and robustness analysis of photonic circuits for autonomous quantum error correction. We outline a workflow for quantum photonic circuit analysis that leverages the Modelica framework for multi-domain physical modeling, which parallels a previously described approach based on VHSIC Hardware Description Language (VHDL).
Circuit-Level Model of Phase-Locked Spin-Torque Oscillators
NASA Astrophysics Data System (ADS)
Ahn, Sora; Lim, Hyein; Kim, Miryeon; Shin, Hyungsoon; Lee, Seungjun
2013-04-01
Spin-torque oscillators (STOs) are new oscillating devices based on spintronics technology with many advantageous features, i.e., nanoscale size, high tunability, and compatibility with standard silicon processing. Recent research has shown that two electrically connected STOs may operate as a single device when specific conditions are met. To overcome the limitation of the small output power of STOs, the phase-locking behavior of multiple STOs is hereby extensively investigated. In this paper, we present a circuit-level model of two coupled STOs considering the interaction between them such that it can represent the phase-locking behavior of multiple STOs. In our model, the characteristics of each STO are defined first as functions of applied DC current and external magnetic field. Then, the phase-locking condition is examined to determine the properties of the two coupled STOs on the basis of a theoretical model. The analytic model of two coupled STOs is written in Verilog-A hardware description language. The behavior of the proposed model is verified by circuit-level simulation using HSPICE with CMOS circuits including a current-mirror circuit and differential amplifiers. Simulation results with various CMOS circuits have confirmed the effectiveness of our model.
Real Time Models of the Asynchronous Circuits: The Delay Theory
Serban E. Vlad
2004-12-17
The chapter from the book introduces the delay theory, whose purpose is the modeling of the asynchronous circuits from digital electrical engineering with ordinary and differential pseudo-boolean equations.
ERIC Educational Resources Information Center
Gabel, Dorothy; And Others
1992-01-01
Chemistry can be described on three levels: sensory, molecular, and symbolic. Proposes a particle approach to teaching chemistry that uses magnets to aid students construct molecular models and solve particle problems. Includes examples of Johnstone's model of chemistry phenomena, a problem worksheet, and a student concept mastery sheet. (MDH)
Simple SPICE model for comparison of CMOS output driver circuits
Hermann, John Karl
1993-01-01
on CMOS technologies. Journal model is IEEE 'I?ansactions on Automatic Control. A. Literature Survey Research has been done in the past concerning noise generated by digital logic de- vices. In particular, Advanced CMOS Logic (ACL) integrated circuits... supply voltage are easy to incorporate. A. Model Attributes Integrated circuits are filled with various parasitic components. Some of these par- asitics aid the design effort. More often than not, however, parasitic components that are large enough...
A statistical MOSFET modeling method for CMOS integrated circuit simulation
Chen, Jian
1992-01-01
A STATISTICAL MOSFET MODELING METHOD FOR CMOS IN'I'EGRATED CIRCUIT SIMULATION A Thesis by JIAN CHEN Submitted to the Office of Graduate Studies of Texas AE~M University in partial fulfillment of the requirements for the degree of MASTER... OF SCIENCE August l 99'2 Major Sub ject: Electrical Engineering A STATISTICAL MOSFET MODELING METHOD FOR CMOS INTEGRATED CIRCUIT SIMULATION A Thesis by JIAN CHEN Approved as to style and content by: H. Maciej . Styblinski ) (Chair of Committee...
Altarawneh, Moaz M [Los Alamos National Laboratory; Mielke, Charles H [Los Alamos National Laboratory
2009-01-01
A new radio frequency oscillator circuit based on a proximity detector integrated circuit is described as an alternative for the traditional tunnel diode oscillator used for pulsed magnetic field measurements at low temperatures. The new circuit has been successfully applied to measure the superconducting upper critical field in Ba{sub 0.55}K{sub 0.45}Fe{sub 2}As{sub 2} single crystfl.ls up to 60 T. The new circuit design avoids many of the problems associated with tunnel diode circuits while keeping the advantages of contact less measurements in pulsed magnets.
Micromagnetic Modelling of Nanocomposite Magnets
Thomas Schrefl; Josef Fidler; Dieter Süss
Finite element modelling treats magnetization processes within on a length scale of several nanometers and thus give a quantitative correlation between the microstructure and the magnetic properties of nanocomposite magnets. The numerical solution of the Gilbert equation of motion shows how reversed domains nucleate and expand. Magnetization reversal starts at the grain boundaries disolving a strongly nonuniform magnetic state. The
Natti, Satish
2010-01-14
New maintenance techniques for circuit breakers are studied in this dissertation by proposing a probabilistic maintenance model and a new methodology to assess circuit breaker condition utilizing its control circuit data. A risk-based decision...
SIMPEL: Circuit model for photonic spike processing laser neurons
NASA Astrophysics Data System (ADS)
Shastri, Bhavin J.; Nahmias, Mitchell A.; Tait, Alexander N.; Wu, Ben; Prucnal, Paul R.
2015-03-01
We propose an equivalent circuit model for photonic spike processing laser neurons with an embedded saturable absorber---a simulation model for photonic excitable lasers (SIMPEL). We show that by mapping the laser neuron rate equations into a circuit model, SPICE analysis can be used as an efficient and accurate engine for numerical calculations, capable of generalization to a variety of different laser neuron types found in literature. The development of this model parallels the Hodgkin--Huxley model of neuron biophysics, a circuit framework which brought efficiency, modularity, and generalizability to the study of neural dynamics. We employ the model to study various signal-processing effects such as excitability with excitatory and inhibitory pulses, binary all-or-nothing response, and bistable dynamics.
SIMPEL: Circuit model for photonic spike processing laser neurons
Shastri, Bhavin J; Tait, Alexander N; Wu, Ben; Prucnal, Paul R
2014-01-01
We propose an equivalent circuit model for photonic spike processing laser neurons with an embedded saturable absorber---a simulation model for photonic excitable lasers (SIMPEL). We show that by mapping the laser neuron rate equations into a circuit model, SPICE analysis can be used as an efficient and accurate engine for numerical calculations, capable of generalization to a variety of different laser neuron types found in literature. The development of this model parallels the Hodgkin--Huxley model of neuron biophysics, a circuit framework which brought efficiency, modularity, and generalizability to the study of neural dynamics. We employ the model to study various signal-processing effects such as excitability with excitatory and inhibitory pulses, binary all-or-nothing response, and bistable dynamics.
Circuit Modeling of Injection Probes for Bulk Current Injection
Flavia Grassi; Filippo Marliani; Sergio A. Pignari
2007-01-01
In this paper, two procedures are developed for lumped-parameter circuit modeling of injection probes for bulk current injection (BCI). Both procedures are based on frequency-domain scattering-parameter measurements, and refer to a clamped wiring composed of a single-ended interconnection. One procedure exploits a black-box approach, requires a calibration fixture, and is suited for practical implementation. The other is based on circuit
Parallel LC circuit model for multi-band absorption and preliminary design of radiative cooling.
Feng, Rui; Qiu, Jun; Liu, Linhua; Ding, Weiqiang; Chen, Lixue
2014-12-15
We perform a comprehensive analysis of multi-band absorption by exciting magnetic polaritons in the infrared region. According to the independent properties of the magnetic polaritons, we propose a parallel inductance and capacitance(PLC) circuit model to explain and predict the multi-band resonant absorption peaks, which is fully validated by using the multi-sized structure with identical dielectric spacing layer and the multilayer structure with the same strip width. More importantly, we present the application of the PLC circuit model to preliminarily design a radiative cooling structure realized by merging several close peaks together. This omnidirectional and polarization insensitive structure is a good candidate for radiative cooling application. PMID:25607485
Numerical modeling of magnetic devices
P. Zhou; W. N. Fu; D. Lin; S. Stanton; Z. J. Cendes
2004-01-01
We present a general approach to directly couple finite-element models with arbitrary electric circuits for application to electromagnetic devices. We describe both two-dimensional (2-D) and three-dimensional (3-D) transient finite-element models, with emphasis on 3-D using a T-? formulation. For 3-D transient and circuit coupling, the derivation of the induced voltage is an integral part of the coupling approach, and the
A New Circuit Simulation Model of Ferroelectric Capacitors
NASA Astrophysics Data System (ADS)
Tamura, Tetsuro; Arimoto, Yoshihiro; Ishiwara, Hiroshi
2002-04-01
A circuit simulation model of ferroelectric capacitors was developed. Because of the complicated voltage and time dependence of polarization switching, simulation of the hysteretic behavior was applicable in the limited condition where the voltage change was of a constant rate or step like. The new model consists of parallel element capacitors each of which has different coercive voltage, switching charge and switching response to the voltage change. The model can be implemented in a SPICE simulator with simple expression, and it successfully reproduces the voltage and time dependence of polarization change under arbitrary conditions. Circuit simulation using this model can easily predict the behavior of ferroelectric capacitors and problems in the device operation.
Modelling of circuit breakers in the Electromagnetic Transients Program
V. Phaniraj; A. G. Phadke
1988-01-01
The recent publication of experimental and theoretical results from verified arc models has made possible the implementation and testing of a dynamic circuit-breaker model using the Electromagnetic Transients Program (EMTP). An estimator was developed to obtain model parameters from test data. Results obtained with the estimator are given, and its data requirements are specified. To illustrate an application of the
MOS transistor modeling for RF integrated circuit design
Christian Enz
2000-01-01
The design of radio-frequency (RF) integrated circuits in deep-submicron CMOS processes requires accurate and scalable compact models of the MOS transistor that are valid in the GHz frequency range and even beyond. Unfortunately, the currently available compact models give inaccurate results if they are not modified adequately. This paper presents the basis of the modeling of the MOS transistor for
Design of interface circuits with electrical battery models
Yoon-Ho Kim; Hoi-Doo Ha
1997-01-01
In designing interface circuits to a battery, often the battery is assumed to be a simple voltage source. However, the battery itself has internal parameters. This means that the internal parameters of the battery models need to be considered for the interface design. Several electrical battery models are presented. Then, using these electrical battery models, the analysis and the design
Combination of Thermal Subsystems Modelled by Rapid Circuit Transformation
Gerstenmaier, Y C; Wachutka, G
2008-01-01
This paper will deal with the modeling-problem of combining thermal subsystems (e.g. a semiconductor module or package with a cooling radiator) making use of reduced models. The subsystem models consist of a set of Foster-type thermal equivalent circuits, which are only behavioral models. A fast al-gorithm is presented for transforming the Foster-type circuits in Cauer-circuits which have physical behavior and therefore allow for the construction of the thermal model of the complete system. Then the set of Cauer-circuits for the complete system is transformed back into Foster-circuits to give a simple mathematical representation and applicability. The transfor-mation algorithms are derived in concise form by use of recur-sive relations. The method is exemplified by modeling and measurements on a single chip IGBT package mounted on a closed water cooled radiator. The thermal impedance of the complete system is constructed from the impedances of the sub-systems, IGBT-package and radiator, and also the impedance...
Combination of Thermal Subsystems Modelled by Rapid Circuit Transformation
Y. C. Gerstenmaier; W. Kiffe; G. Wachutka
2008-01-07
This paper will deal with the modeling-problem of combining thermal subsystems (e.g. a semiconductor module or package with a cooling radiator) making use of reduced models. The subsystem models consist of a set of Foster-type thermal equivalent circuits, which are only behavioral models. A fast al-gorithm is presented for transforming the Foster-type circuits in Cauer-circuits which have physical behavior and therefore allow for the construction of the thermal model of the complete system. Then the set of Cauer-circuits for the complete system is transformed back into Foster-circuits to give a simple mathematical representation and applicability. The transfor-mation algorithms are derived in concise form by use of recur-sive relations. The method is exemplified by modeling and measurements on a single chip IGBT package mounted on a closed water cooled radiator. The thermal impedance of the complete system is constructed from the impedances of the sub-systems, IGBT-package and radiator, and also the impedance of the package can be inferred from the measured impedance of the complete system.
A VACUUM CIRCUIT-BREAKER WITH PERMANENT MAGNETIC ACTUATOR AND ELECTRONIC CONTROL
Edgar Dullni; Harald Fink; Christian Reuber
Vacuum circuit-breakers have obtained a high level of performance, reliability and safety. This is mostly owed to the advantages of current interruption in vacuum. How- ever, the design of the mechanical drive, which has al- ready been applied e.g. in minimum oil-breakers, has hardly been changed. With the introduction of an actuator with permanent magnetic limit positions and electro- magnetically
A vacuum circuit-breaker with permanent magnetic actuator for frequent operations
Edgar Dullni
1998-01-01
Vacuum circuit-breakers have obtained a high level of performance, reliability and safety. This is mostly owed to the advantages of current interruption in vacuum. However, the design of the mechanical drive, which has already been applied e.g. in minimum oil-breakers, has hardly been changed. With the introduction of an actuator with permanent magnetic limit positions and electro-magnetically controlled motion, the
Jong-Ho Jeong; Eun-Woong Lee; Hyun-Kil Cho
2003-01-01
Finite element method is very flexible for new shapes and provides to us flux distribution, magnetomotive force, eddy currents, and torques. However, finite element method needs to long calculation time in order to desired accuracy. Magnetic equivalent circuit method takes the computation time less than finite element method. Therefore, finite element method mainly use to confirm the completed design and
Kleinfeld, David
SET/RESET PULSE CIRCUITS FOR MAGNETIC SENSORS AN-201 Honeywell's line of magnetoresistive permalloy, the sensor characteristics. This effect will be referred to as applying a set pulse or reset pulse. Polarity. If a +4 amp pulse is used to "set" the sensor, the pulse decay should not drop below zero current. Any
Circuit oriented average modeling of switching power converters
Carlos E. Cuadros Ortiz
2005-01-01
Effective features from various modeling methods are complemented with analog simulation and series expansion practices as well as heuristic guidelines to form a systematic and versatile method to derive accurate and efficient circuit oriented large signal average models (COLSAMs) that approximate the slow dynamics manifold of the moving average values of the relevant state variables for pulse-width modulated (PWM) dc
Qubit logic modeling by electronic circuits and electromagnetic signals
G. A. Kouzaev
2001-08-07
In the paper an approach is presented allowing to model quantum logic circuits by electronic gates for discrete spatially modulated electromagnetic signals. The designed circuitry is for modeling low scale quantum nets of general design and quantum devices based only on superposition principle of their work.
Bipolar transistor modeling of avalanche generation for computer circuit simulation
R. W. Dutton
1975-01-01
An avalanche generation model is developed and incorporated into computer circuit analysis programs SLIC and NICAP. A modified form of Miller's empirical expression for generation is found to agree well with measured data for Western Electric and commercial n-p-n transistors. Measurement techniques and parameter determination for the three model coefficients are discussed. Equation constraints appropriate for computer implementation are presented.
The simulation model and ASIC implementation of a random bit source circuit
Yanfang Wang; Haibin Shen
2009-01-01
This paper presents a random bit source circuit for information security SoC platform application. A new type of oscillator, taking the form of combinational logic circuit and using complex feedback networks, is applied in the circuit. A series of MATLAB\\/Simulink models based on the circuit structure are established for the random bit source. To improve the accuracy, models for the
External circuit integration with electromagnetic particle in cell modeling of plasma focus devices
NASA Astrophysics Data System (ADS)
Seng, Y. S.; Lee, P.; Rawat, R. S.
2015-03-01
The pinch performance of a plasma focus (PF) device is sensitive to the physical conditions of the breakdown phase. It is therefore essential to model and study the initial phase in order to optimize device performance. An external circuit is self consistently coupled to the electromagnetic particle in cell code to model the breakdown and initial lift phase of the United Nations University/International Centre for Theoretical Physics (UNU-ICTP) plasma focus device. Gas breakdown during the breakdown phase is simulated successfully, following a drop in the applied voltage across the device and a concurrent substantial rise in the circuit current. As a result, the plasma becomes magnetized, with the growing value of the magnetic field over time leading to the gradual lift off of the well formed current sheath into the axial acceleration phase. This lifting off, with simultaneous outward sheath motion along the anode and vertical cathode, and the strong magnetic fields in the current sheath region, was demonstrated in this work, and hence validates our method of coupling the external circuit to PF devices. Our method produces voltage waveforms that are qualitatively similar to the observed experimental voltage profiles of the UNU-ICTP device. Values of the mean electron energy before and after voltage breakdown turned out to be different, with the values after breakdown being much lower. In both cases, the electron energy density function turned out to be non-Maxwellian.
Delay modeling and glitch estimation for CMOS circuits
Shiau, Yan-Chyuan
1988-01-01
DELAY MODELING AND GLITCH ESTIMATION FOR CMOS CIRCUITS A Thesis by YAN-CHYUAN SHIAU Submitted to the Graduate College of Texas A8rM University in partial fulfillment of the requirement for the degree of MASTER OF SCIENCE August 1988 Major... Subject: Electrical Engineering DELAY MODELING AND GLITCH ESTIMATION FOR CMOS CIRCUITS A Thesis by YAN-CHYUAN SHIAU Approved as to style and content by: An-Chang Deng (Chairman of Committee) Karan Watson (Member) I / l j j Stephen M. Morg...
Optimality of partial adiabatic search and its circuit model
NASA Astrophysics Data System (ADS)
Mei, Ying; Sun, Jie; Lu, Songfeng; Gao, Chao
2014-08-01
In this paper, we first uncover a fact that a partial adiabatic quantum search with time complexity is in fact optimal, in which is the total number of elements in an unstructured database, and () of them are the marked ones(one) . We then discuss how to implement a partial adiabatic search algorithm on the quantum circuit model. From the implementing procedure on the circuit model, we can find out that the approximating steps needed are always in the same order of the time complexity of the adiabatic algorithm.
Using Hydraulic Network Models to Teach Electric Circuit Principles
NASA Astrophysics Data System (ADS)
Jones, Irvin; EERC (Engineering Education Research Center) Collaboration
2013-11-01
Unlike other engineering disciplines, teaching electric circuit principles is difficult for some students because there isn't a visual context to rely on. So concepts such as electric potential, current, resistance, capacitance, and inductance have little meaning outside of their definition and the derived mathematical relationships. As a work in progress, we are developing a tool to support teaching, learning, and research of electric circuits. The tool will allow the user to design, build, and operate electric circuits in the form of hydraulic networks. We believe that this system will promote greater learning of electric circuit principles by visually realizing the conceptual and abstract concepts of electric circuits. Furthermore, as a teaching and learning tool, the hydraulic network system can be used to teach and improve comprehension of electrical principles in K through 12 classrooms and in cross-disciplinary environments such as Bioengineering, Mechanical Engineering, Industrial Engineering, and Aeronautical Engineering. As a research tool, the hydraulic network can model and simulate micro/nano bio-electro-chemical systems. Unlike other engineering disciplines, teaching electric circuit principles is difficult for some students because there isn't a visual context to rely on. So concepts such as electric potential, current, resistance, capacitance, and inductance have little meaning outside of their definition and the derived mathematical relationships. As a work in progress, we are developing a tool to support teaching, learning, and research of electric circuits. The tool will allow the user to design, build, and operate electric circuits in the form of hydraulic networks. We believe that this system will promote greater learning of electric circuit principles by visually realizing the conceptual and abstract concepts of electric circuits. Furthermore, as a teaching and learning tool, the hydraulic network system can be used to teach and improve comprehension of electrical principles in K through 12 classrooms and in cross-disciplinary environments such as Bioengineering, Mechanical Engineering, Industrial Engineering, and Aeronautical Engineering. As a research tool, the hydraulic network can model and simulate micro/nano bio-electro-chemical systems. Organization within the Swanson School of Engineering at the University of Pittsburgh.
Magnetic modelling of strongly magnetized bodies
NASA Astrophysics Data System (ADS)
Koppelt, U.; Abrahamsen, N.; Voss, O.
At different prehistoric iron production sites near Varde in SW Jutland (Denmark) several thousands slag bodies remained after the smeltings and were located by magnetic surveying. Total magnetic field data measured over isolated slag bodies were inverted to determine the direction of the remanent magnetization. Palaeomagnetic investigations were carried out for dating purposes. The large scatter of palaeomagnetic directions obtained for different specimens from a single slag body was interpreted in terms of shape anisotropy (magnetic refraction). By an integral equation technique the effect of magnetic refraction was modelled. Charts were computed to correct the inversion results. The obtained directions correspond to the directions predicted by the secular variation curve for the appropriate period of time and to C 14 datings from the same archaeological site.
MOSFET modeling for low noise, RF circuit design
M. Jamal Deen; Chih-Hung Chen; Yuhua Cheng
2002-01-01
In this paper, high frequency (HF) AC and noise modeling of MOSFETs for low noise, radio frequency (RF) integrated circuit (IC) design are discussed. Scalable parasitic model and the Non-Quasi-Static (NQS) model are discussed and verified with the measured data. For the noise modeling, extracted noise sources of MOSFETs in 0.18 pm CMOS process and from RF noise measurements are
Notes on Magnetic Circuits ME 104, Prof. B. Paden
Paden, Brad
in mechatronics as they appear in a number of actuators and sensors. Example applications are electric motors,000 for 50%Ni-Fe. A typical range for motors and actuators is 1000-2000 for the commonly used silicon irons for the magnetic field and flux, we have NI B H l = = (6) and #12;}magneto-motive force (mmf) reluctance, NIA Ni
Boyer, Edmond
the behavior of rotating arcs in vacuum circuit breakers. Index Terms--Electrical arc model, finite element method (FEM), vacuum arc, vaccum circuit breakers. I. INTRODUCTION THE goal of circuit breakers of electrical arc in vacuum is complex and still not really understood. The magnetic field created
Statistical modeling of SRAM yield performance and circuit variability
NASA Astrophysics Data System (ADS)
Cheng, Qi; Chen, Yijian
2015-03-01
In this paper, we develop statistical models to investigate SRAM yield performance and circuit variability in the presence of self-aligned multiple patterning (SAMP) process. It is assumed that SRAM fins are fabricated by a positivetone (spacer is line) self-aligned sextuple patterning (SASP) process which accommodates two types of spacers, while gates are fabricated by a more pitch-relaxed self-aligned quadruple patterning (SAQP) process which only allows one type of spacer. A number of possible inverter and SRAM structures are identified and the related circuit multi-modality is studied using the developed failure-probability and yield models. It is shown that SRAM circuit yield is significantly impacted by the multi-modality of fins' spatial variations in a SRAM cell. The sensitivity of 6-transistor SRAM read/write failure probability to SASP process variations is calculated and the specific circuit type with the highest probability to fail in the reading/writing operation is identified. Our study suggests that the 6-transistor SRAM configuration may not be scalable to 7-nm half pitch and more robust SRAM circuit design needs to be researched.
Distributed-element circuit model of edge magnetoplasmon transport
NASA Astrophysics Data System (ADS)
Hashisaka, Masayuki; Kamata, Hiroshi; Kumada, Norio; Washio, Kazuhisa; Murata, Ryuji; Muraki, Koji; Fujisawa, Toshimasa
2013-12-01
We report experimental and theoretical studies of edge magnetoplasmon (EMP) transport in quantum Hall (QH) devices. We develop a model that allows us to calculate the transport coefficients of EMPs in QH devices with various geometries. In our model, a QH system is described as a chiral distributed-element (CDE) circuit, where the effects of Coulomb interaction are represented by an electrochemical capacitance distributed along unidirectional transmission lines. We measure the EMP transport coefficients through single- and coupled-edge channels, a quantum point contact, and single- and double-cavity structures. These measured transmission spectra can be reproduced well by simulations using the corresponding CDE circuits. By fitting the experimental results with the simulations, we deduce the circuit parameters that characterize the electrostatic environment around the edge channels in a realistic QH system. The observed gate-voltage dependences of the EMP transport properties in gate-defined structures are explained in terms of the gate tuning of the circuit parameters in CDE circuits.
A simple MOSFET model for circuit analysis
Takayasu Sakurai; A. Richard Newton
1991-01-01
A simple, general, yet realistic MOSFET model, the nth power law MOSFET model, is introduced. The model can express I- V characteristics of short-channel MOSFETs at least down to 0.25-?m channel length and of resistance inserted MOSFETs. The model evaluation time is about 1\\/3 of the evaluation time of the SPICE3 MOS LEVEL3 model. The model parameter extraction is done
Altarawneh, M M; Mielke, C H; Brooks, J S
2009-06-01
A radio frequency oscillator circuit based on a proximity detector integrated circuit is described as an alternative for the traditional tunnel diode oscillator used for pulsed magnetic field measurements at low temperatures. The proximity detector circuit design, although less sensitive than tunnel diode oscillator circuits, has a number of essential advantages for measurements in the extreme environments of pulsed magnetic fields. These include the insensitivity of operation to voltages induced in the inductor coil, the elimination of a diode bias circuit and tuning, and a broad dynamic range of resonant frequency variation. The circuit has been successfully applied to measure the superconducting upper critical field in Ba(0.55)K(0.45)Fe2As2 single crystals up to 60 T. PMID:19566232
Generalized Partial Element Equivalent Circuit (PEEC) Modeling With Radiation Effect
Lap K. Yeung; Ke-Li Wu
2011-01-01
In this paper, a new frequency-domain formulation of the partial element equivalent circuit (PEEC) model incorporating the concept of generalized complex partial inductance and pure real capacitance is introduced for modeling of 3-D structures, to which the radiation effect is not negligible. Unlike conven- tional PEEC-based models, the proposed formulation accounts for the radiation effect by introducing physically meaningful complex-valued
A new equivalent circuit model for micro electroporation systems
Hooman Shagoshtasbi; Yi-Kuen Lee
2011-01-01
Electroporation (EP) is a unique biotechnique in which intense electric pulses are applied on the cell membrane to temporarily generate nanoscale electropores and to increase the membrane permeability for the delivery of exogenous biomolecules or drugs. We propose a new equivalent circuit model with 8 electric components to predict the electrodynamic response of a micro EP system. As the permeability
EMI Modeling of Integrated Circuits using pattern simulation
Paris-Sud XI, Université de
EMI Modeling of Integrated Circuits using pattern simulation COURAU Lionel, GERBERT-GAILLARD Brice finishing, a new noise simulation has been developped in order to be fast and accurate. Then some comparisons have been made with standard spice simulations showing the efficiency of this flow. 1
GABAergic circuit dysfunction in the Drosophila Fragile X syndrome model
Broadie, Kendal S.
GABAergic circuit dysfunction in the Drosophila Fragile X syndrome model Cheryl L. Gatto, Daniel in a range of neurodevelop- mental disorders, including autism, epilepsy, Rett syndrome, and Fragile X Accepted 7 January 2014 Available online 12 January 2014 Keywords: Fragile X mental retardation protein
Monte Carlo Reliability Model for Microwave Monolithic Integrated Circuits
Rubloff, Gary W.
Monte Carlo Reliability Model for Microwave Monolithic Integrated Circuits Aris Christou Materials of the failure rate of each component due to interaction effects of the failed components. The Monte Carlo failure rates become nonconstant. The Monte Carlo technique is an appropriate methodology used to treat
Design and modeling of coupled pulse magnets (electrical and thermal)
Y. M. Eyssa; P. Pernambuco Wise
1996-01-01
Design and optimization of pulsed magnets requires development of computer codes that can analyze a multi-coil magnet system magnetically, thermally and mechanically. We present a FORTRAN computer code “Xheat” that can be used to design a multi-circuit pulsed magnet using one or more conductors and reinforcement materials. Xheat is circuit solver that can analyze nonlinear magnetically coupled LR and LRC
NSDL National Science Digital Library
2012-08-03
This is a summative activity about magnets. Learners will observe a demonstration of the action of a magnet on a test tube of iron filings, answer questions, and, using the concepts learned in previous activities, write an essay about their understanding of the demonstration. This is the fourth activity in the Mapping Magnetic Influence educators guide. Learners should complete the other three activities in that guide (Seeing Magnetism, What Do You Know about Magnets, and Magnet Map) prior to beginning this activity.
Cardiopulmonary Circuit Models for Predicting Injury to the Heart
NASA Astrophysics Data System (ADS)
Ward, Richard; Wing, Sarah; Bassingthwaighte, James; Neal, Maxwell
2004-11-01
Circuit models have been used extensively in physiology to describe cardiopulmonary function. Such models are being used in the DARPA Virtual Soldier (VS) Project* to predict the response to injury or physiological stress. The most complex model consists of systemic circulation, pulmonary circulation, and a four-chamber heart sub-model. This model also includes baroreceptor feedback, airway mechanics, gas exchange, and pleural pressure influence on the circulation. As part of the VS Project, Oak Ridge National Laboratory has been evaluating various cardiopulmonary circuit models for predicting the effects of injury to the heart. We describe, from a physicist's perspective, the concept of building circuit models, discuss both unstressed and stressed models, and show how the stressed models are used to predict effects of specific wounds. *This work was supported by a grant from the DARPA, executed by the U.S. Army Medical Research and Materiel Command/TATRC Cooperative Agreement, Contract # W81XWH-04-2-0012. The submitted manuscript has been authored by the U.S. Department of Energy, Office of Science of the Oak Ridge National Laboratory, managed for the U.S. DOE by UT-Battelle, LLC, under contract No. DE-AC05-00OR22725. Accordingly, the U.S. Government retains a non-exclusive, royalty-free license to publish or reproduce the published form of this contribution, or allow others to do so, for U.S. Government purpose.
Wilian Oliveira; Mauro Uemori; Johnny Rocha; Renato Carlson
2009-01-01
Generator air gap non-uniformity causes an imbalance of magnetic forces that result in unbalanced magnetic pull - UMP. This phenomenon can cause high vibrations on the rotor. The addition of equipotential connections leads to an increment of the circulating current among parallel circuits of the stator winding, decreasing the magnetomotive force of armature reaction. Since the forces of magnetic attraction
Tze-Fun Chan; Weimin Wang; Loi Lei Lai
2009-01-01
The performance analysis of a permanent-magnet synchronous generator with surface-inset rotor feeding a rectifier load is described. The time-stepping, coupled-circuit, two-dimensional finite-element method enables the instantaneous values of field and circuit variables to be solved simultaneously. Useful generator information, such as the air gap flux distribution, voltage and current waveforms, steady-steady performance and short circuit transients can thus be obtained.
Surrogate Modeling of RF Circuit Blocks
Luciano De Tommasi; Dirk Gorissen; Jeroen A. Croon; Tom Dhaene
\\u000a Surrogate models are a cost-effective replacement for expensive computer simulations in design space exploration. Literature\\u000a has already demonstrated the feasibility of accurate surrogate models for single radio frequency (RF) and microwave devices.\\u000a Within the European Marie Curie project O-MOORE-NICE! (Operational Model Order Reduction for Nanoscale IC Electronics) we\\u000a aim to investigate the feasibility of the surrogate modeling approach for entire
Computer model simulation of null-flux magnetic suspension and guidance
He, Jianliang; Rote, D.M.
1992-06-01
This paper discusses the magnetic force computations in a null-flux suspension system using dynamic circuit theory. A computer simulation model that can be used to compute magnetic forces and predict the system performance is developed on the basis of dynamic circuit theory. Numerical examples are presented to demonstrate the application of the model. The performance of the null-flux suspension system is simulated and discussed. 8 refs.
Computer model simulation of null-flux magnetic suspension and guidance
He, Jianliang; Rote, D.M.
1992-01-01
This paper discusses the magnetic force computations in a null-flux suspension system using dynamic circuit theory. A computer simulation model that can be used to compute magnetic forces and predict the system performance is developed on the basis of dynamic circuit theory. Numerical examples are presented to demonstrate the application of the model. The performance of the null-flux suspension system is simulated and discussed. 8 refs.
Hirofumi Seki; Satoshi Takemori; T. Sato
1995-01-01
An efficient nitrogen laser has been developed. The exciter of the nitrogen laser employs a magnetic pulse compression circuit. A laser pulsed energy of 20 mJ is achieved under a single-pulsed mode, with an efficiency of 1.3% to the output energy of the exciter, and 0.43% to the charging energy. Several types of electrodes were tested. A maximum efficiency and
Yield learning model for integrated circuit package
Balasubramaniam, Gaurishankar
1996-01-01
from chronic yield loss. . 5 Yield due to chronic yield loss. . 6 Time series model. . 7 Estimation of regression coefficients. . . 14 . 16 . 17 . 18 8 Impact of excursions. . . . 19 9 Effect of volume in line. . . . . . 20 10 Impact... of experience level. 11 Final spreadsheet model. . 12 Values for factors. . 21 . . . . 22 . . . . . 23 13 Final yield. . . . . . 24 14 Predicted yield - chronic and excursions. . . 25 15 Percentage rating for PQFP - absolute metric model. . . . . 16...
A model of neural circuits for programmable VLSI implementation
Fathi M. A. Salam
1989-01-01
A new model for neural circuits is introduced which has qualitatively the same dynamic properties as gradient continuous-time feedback neural nets. This model (i) reduces the maximum number of connections to n(n+1)\\/2, (ii) does not suffer from the synaptic weight problem, i.e. the problem of implementing variable linear resistive elements in large scale, and (iii) is implementable via all MOS
Development of a numerical computer code and circuit element models for simulation of firing systems
Carpenter, K.H. (Kansas State Univ., Manhattan, KS (USA). Dept. of Electrical and Computer Engineering)
1990-07-02
Numerical simulation of firing systems requires both the appropriate circuit analysis framework and the special element models required by the application. We have modified the SPICE circuit analysis code (version 2G.6), developed originally at the Electronic Research Laboratory of the University of California, Berkeley, to allow it to be used on MSDOS-based, personal computers and to give it two additional circuit elements needed by firing systems--fuses and saturating inductances. An interactive editor and a batch driver have been written to ease the use of the SPICE program by system designers, and the interactive graphical post processor, NUTMEG, supplied by U. C. Berkeley with SPICE version 3B1, has been interfaced to the output from the modified SPICE. Documentation and installation aids have been provided to make the total software system accessible to PC users. Sample problems show that the resulting code is in agreement with the FIRESET code on which the fuse model was based (with some modifications to the dynamics of scaling fuse parameters). In order to allow for more complex simulations of firing systems, studies have been made of additional special circuit elements--switches and ferrite cored inductances. A simple switch model has been investigated which promises to give at least a first approximation to the physical effects of a non ideal switch, and which can be added to the existing SPICE circuits without changing the SPICE code itself. The effect of fast rise time pulses on ferrites has been studied experimentally in order to provide a base for future modeling and incorporation of the dynamic effects of changes in core magnetization into the SPICE code. This report contains detailed accounts of the work on these topics performed during the period it covers, and has appendices listing all source code written documentation produced.
Circuit models of stochastic genetic networks
Mandal, Soumyajit
We use analogies between chemistry and subthreshold electronics to develop fast, scalable, digitally programmable hardware models of stochastic genetic networks. We also present experimental results from a prototype 0.18 ...
Development of circuit model for arcing on solar panels
NASA Astrophysics Data System (ADS)
Mehta, Bhoomi K.; Deshpande, S. P.; Mukherjee, S.; Gupta, S. B.; Ranjan, M.; Rane, R.; Vaghela, N.; Acharya, V.; Sudhakar, M.; Sankaran, M.; Suresh, E. P.
2010-02-01
The increased requirements of payload capacity of the satellites have resulted in much higher power requirements of the satellites. In order to minimize the energy loss during power transmission due to cable loss, use of high voltage solar panels becomes necessary. When a satellite encounters space plasma it floats negatively with respect to the surrounding space plasma environment. At high voltage, charging and discharging on solar panels causes the power system breakdown. Once a solar panel surface is charged and potential difference between surface insulator and conductor exceeds certain value, electrostatic discharge (ESD) may occur. This ESD may trigger a secondary arc that can destroy the solar panel circuit. ESD is also called as primary or minor arc and secondary is called major arc. The energy of minor arc is supplied by the charge stored in the coverglass of solar array and is a pulse of typically several 100 ns to several 100 ?s duration. The damage caused by minor arc is less compared to major arcs, but it is observed that the minor arc is cause of major arc. Therefore it is important to develop an understanding of minor arc and mitigation techniques. In this paper we present a linear circuit analysis for minor arcs on solar panels. To study arcing event, a ground experimental facility to simulate space plasma environment has been developed at Facilitation Centre for Industrial Plasma Technologies (Institute for Plasma Research) in collaboration with Indian Space Research Organization's ISRO Satellite Technology Centre (ISAC). A linear circuit model has been developed to explain the experimental results by representing the coverglass, solar cell interconnect and wiring by an LCR circuit and the primary arc by an equivalent LR circuit. The aim of the circuit analysis is to predict the arc current which flows through the arc plasma. It is established from the model that the current depends on various parameters like potential difference between insulator and conductor, arc resistance, stored charge in the solar cell coverglass and the external capacitor that simulates wire harness. A close correlation between the experiments and circuit model results has been observed.
da Silva, Isaias; Horikawa, Oswaldo; Cardoso, Jose R; Camargo, Fernando A; Andrade, Aron J P; Bock, Eduardo G P
2011-05-01
In previous studies, we presented main strategies for suspending the rotor of a mixed-flow type (centrifugal and axial) ventricular assist device (VAD), originally presented by the Institute Dante Pazzanese of Cardiology (IDPC), Brazil. Magnetic suspension is achieved by the use of a magnetic bearing architecture in which the active control is executed in only one degree of freedom, in the axial direction of the rotor. Remaining degrees of freedom, excepting the rotation, are restricted only by the attraction force between pairs of permanent magnets. This study is part of a joint project in development by IDPC and Escola Politecnica of São Paulo University, Brazil. This article shows advances in that project, presenting two promising solutions for magnetic bearings. One solution uses hybrid cores as electromagnetic actuators, that is, cores that combine iron and permanent magnets. The other solution uses actuators, also of hybrid type, but with the magnetic circuit closed by an iron core. After preliminary analysis, a pump prototype has been developed for each solution and has been tested. For each prototype, a brushless DC motor has been developed as the rotor driver. Each solution was evaluated by in vitro experiments and guidelines are extracted for future improvements. Tests have shown good results and demonstrated that one solution is not isolated from the other. One complements the other for the development of a single-axis-controlled, hybrid-type magnetic bearing for a mixed-flow type VAD. PMID:21595710
NASA Astrophysics Data System (ADS)
Tian, Rui
Magnetic components are essential parts of power converters. Inductors with magnetic cores are investigated. An eddy current loss model for pot-core inductors is developed with finite elemental analysis (FEA). The reliability of inductors using magnetic cores in a high-temperature environment is investigated. Working in up to 150°C circumstance for a short periods is not destructive for the inductors. Optimization of toroidal inductors in a DC-DC converter is investigated. Parasitic capacitance and the capacitive loss in toroidal inductors are modeled. Standard circuit optimization is performed to explore the energy conversion efficiency of the toroidal inductors. Thermal analysis, light-load efficiency and relative permeability of the toroidal inductor design are also investigated. The toroidal inductor can achieve about 85% efficiency for 3 A DC current and 1 W/mm2 power density. Inductor-only efficiency of toroidal inductors is investigated with revised model. At 100 MHz operating frequency, toroidal inductors can achieve more than 97% inductor efficiency with power density range of 0.7 W/mm2 to 6 W/mm2. The performance of our nanograngular magnetic core is dependent on the angle of the poling magnetic field compared to the field during operation. Experiments on a serious of samples show that the poling angle can deviate by up to 15 degrees from ideal with only a small penalty in performance. The field-angle experiment is intended to prove integrated toroidal inductor process possible. A magnetic fixture model is proposed for large-scale toroidal inductor processing.
Example of Lumped Parameter Modeling of a Quantum Optics Circuit
Paul J. Werbos
2014-09-10
This paper shows that it is sometimes possible for a simple lumped parameter model of a circuit to yield correct quantum mechanical predictions of its behavior, even when there is quantum entanglement between components of that circuit. It addresses a simple but important example, the circuit of the original Bell's Theorem experiments for ideal polarizers. Correct predictions emerge from two alternative simple models based on classical Markov Random Field across space time. Exact agreement with quantum mechanics does not violate Bell's Theorem itself, because the interplay between initial and final outcomes in these calculations does not fall within the classical definition of time forwards causality. Both models raise interesting questions for future research. The final section discusses several possible directions for following up on these results, both in lumped system modeling and in more general approaches. The final section proposes a new experiment with three-photon entanglement which may be able to decide between local realistic MRF models and conventional predictions assuming the usual collapse of the wave function. A new appendix works out what the conventional predictions would be for the new experiment, and also gives a simple master equation version of the collapse assumption which does not involve metaphysical observers. Preliminary indications do suggest that the new expeiment in process may indeed be decisive.
Oracle Circuits for Branching-Time Model Checking
Philippe Schnoebelen
2003-01-01
A special class of oracle circuits with tree-vector form is introduced. It is shown that they can be evaluated in deterministic polynomial-time with a polylog number of adaptive queries to an NP oracle. This framework allows us to evaluate the precise computational complexity of model checking for some branching-time logics where it was known that the problem is NP-hard and
An MOS transistor model for analog circuit design
A. I. A. Cunha; M. C. Schneider; C. Galup-Montoro
1998-01-01
This paper presents a physically based model for the metal-oxide-semiconductor (MOS) transistor suitable for analysis and design of analog integrated circuits. Static and dynamic characteristics of the MOS field-effect transistor are accurately described by single-piece functions of two saturation currents in all regions of operation. Simple expressions for the transconductance-to-current ratio, the drain-to-source saturation voltage, and the cutoff frequency in
Study of the Electromagnetic Field of Transcranial Magnetic Stimulation Based on the Real Head Model
Weizhong He; Peng Zhou; Dongdong Lin; Xin Zhao; MingShi Wang
2009-01-01
This paper presents the application of finite element method in analysis of the electromagnetic field within real head model exposed to a time varying magnetic field produced by the circuit-driving loop. To analyze the electromagnetic field under Transcranial Magnetic Stimulation precisely and display the stimulating effect of the loops in different geometrical forms, a 3-D real head model reconstructed from
DISSECTING OCD CIRCUITS: FROM ANIMAL MODELS TO TARGETED TREATMENTS.
Ahmari, Susanne E; Dougherty, Darin D
2015-08-01
Obsessive-compulsive disorder (OCD) is a chronic, severe mental illness with up to 2-3% prevalence worldwide. In fact, OCD has been classified as one of the world's 10 leading causes of illness-related disability according to the World Health Organization, largely because of the chronic nature of disabling symptoms.([1]) Despite the severity and high prevalence of this chronic and disabling disorder, there is still relatively limited understanding of its pathophysiology. However, this is now rapidly changing due to development of powerful technologies that can be used to dissect the neural circuits underlying pathologic behaviors. In this article, we describe recent technical advances that have allowed neuroscientists to start identifying the circuits underlying complex repetitive behaviors using animal model systems. In addition, we review current surgical and stimulation-based treatments for OCD that target circuit dysfunction. Finally, we discuss how findings from animal models may be applied in the clinical arena to help inform and refine targeted brain stimulation-based treatment approaches. PMID:25952989
Gan Zhang; Ming Cheng; Wei Hua
2010-01-01
In this paper, a nonlinear magnetic circuit network model for the analysis of a three-phase 12-stator-slot\\/10-rotor-pole flux-switching permanent-magnet (FSPM) motor is proposed considering localized saturation effect, which enables the predictions of open-circuit air-gap field distributions, phase flux-linkage, phase back-electro-motive-force (back-EMF) and winding inductances waveforms. Further, a developed model with bypass-bridges is also proposed, which enables the winding inductances to be
Henk Polinder; Johannes G. Slootweg; Martin J. Hoeijmakers; John C. Compter
2003-01-01
The use of linear permanent-magnet (PM) actuators increases in a wide variety of applications because of their high force density, robustness, and accuracy. These linear PM motors are often heavily loaded during short intervals of high acceleration, so that magnetic saturation occurs. This paper models saturation and end effects in linear PM motors using magnetic circuit models. The saturating parts
Z. Q. Zhu; David Howe; Ekkehard Bolte; Bemd Ackermann
1993-01-01
An analytical technique for predicting the instantaneous magnetic field distribution in the airgap region of radial-field topologies of brushless permanent-magnet DC motors, under any specified load condition and accounting implicitly for the stator winding current waveform and the effect of stator-slot-openings, has been developed. It is based on the superposition of the component fields due to the permanent magnet and
Random telegraph signal noise SPICE modeling for circuit simulators
C. Leyris; S. Pilorget; M. Marin; M. Minondo; H. Jaouen
2007-01-01
In small area MOSFET devices widely used in analog and RF circuit design, low frequency noise behavior is increasingly dominated by Random Telegraph Signal noise. For analog circuit designers, awareness of these single electron noise phenomena is crucial. If optimal circuits are to be designed these effects can aid in low noise circuit design if used properly, while they may
Magnetic circuit of a contactless torque sensor for electric power steering
NASA Astrophysics Data System (ADS)
Fröhlich, Ekkehart; Jerems, Frank
Modern passenger cars are increasingly equipped with electromechanical steering assist rather than hydraulic systems known for many decades. Major benefits are reduced fuel consumption (up to 0.2l/100 km) and increased functionality. As such a system reacts to the drivers input in terms of steering torque or steering effort, a sensor is required that accurately measures the steering torque. Valeo has adopted a magnetic technology and has improved the performance by adding specially designed flux concentration devices. The magnetic circuit consists of a multi-pole ring magnet and a pair of ring-shaped soft magnetic parts rotating together with the steering shaft and an additional pair of soft magnetic flux concentration devices which are fixed stationary inside the housing. The steering torque causes a relative twist between magnet and the soft magnetic rings, therefore implementing a proportional magnetisation of the latter. A U-shape was chosen for the flux concentration devices in order to compensate mechanical tolerances of the system. The main focus of this paper will be on the tolerance behaviour of the sensor system and the impact of the flux concentration devices. Because of the nonlinear nature of the magnetisation curve of the NiFe alloy used extensive 3D FEM simulation was necessary. Simulation enables us to have a look inside the soft magnetic material and predict the spatial magnetisation distribution with the benefit of avoiding saturation. The result is an optimised sensor, which meets both the harsh environmental conditions inside the motor compartment as well as the cost pressure in the automotive business.
Universal analytic model for tunnel FET circuit simulation
NASA Astrophysics Data System (ADS)
Lu, Hao; Esseni, David; Seabaugh, Alan
2015-06-01
A simple analytic model based on the Kane-Sze formula is used to describe the current-voltage characteristics of tunnel field-effect transistors (TFETs). This model captures the unique features of the TFET including the decrease in subthreshold swing with drain current and the superlinear onset of the output characteristic. The model also captures the ambipolar current characteristic at negative gate-source bias and the negative differential resistance for negative drain-source biases. A simple empirical capacitance model is also included to enable circuit simulation. The model has fairly general validity and is not specific to a particular TFET geometry. Good agreement is shown with published atomistic simulations of an InAs double-gate TFET with gate perpendicular to the tunnel junction and with numerical simulations of a broken-gap AlGaSb/InAs TFET with gate in parallel with the tunnel junction.
A Fast Block Structure Preserving Model Order Reduction for Inverse Inductance Circuits
He, Lei
]. Existing model order reduction techniques [1], however, stamp L in the MNA This paper is partially circuit reductions stamp inverse induc- tance L-1 elements by a second-order nodal analysis (NA). The NA to a singular ma- trix stamping in general. We introduce a new circuit stamp- ing for RCL-1 circuits using
Modeling and simulation of insulated-gate field-effect transistor switching circuits
HAROLD SHICHMAN; DAVID A. HODGES
1968-01-01
A new equivalent circuit for the insulated-gate field-effect transistor (IGFET) is described. This device model is particularly useful for computer-aided analysis of monolithic integrated IGFET switching circuits. The results of computer simulations using the new equivalent circuit are in close agreement with experimental observations. As an example of a practical application, simulation results are shown for an integrated circuit IGFET
Digital quantum simulation of fermionic models with a superconducting circuit.
Barends, R; Lamata, L; Kelly, J; García-Álvarez, L; Fowler, A G; Megrant, A; Jeffrey, E; White, T C; Sank, D; Mutus, J Y; Campbell, B; Chen, Yu; Chen, Z; Chiaro, B; Dunsworth, A; Hoi, I-C; Neill, C; O'Malley, P J J; Quintana, C; Roushan, P; Vainsencher, A; Wenner, J; Solano, E; Martinis, John M
2015-01-01
One of the key applications of quantum information is simulating nature. Fermions are ubiquitous in nature, appearing in condensed matter systems, chemistry and high energy physics. However, universally simulating their interactions is arguably one of the largest challenges, because of the difficulties arising from anticommutativity. Here we use digital methods to construct the required arbitrary interactions, and perform quantum simulation of up to four fermionic modes with a superconducting quantum circuit. We employ in excess of 300 quantum logic gates, and reach fidelities that are consistent with a simple model of uncorrelated errors. The presented approach is in principle scalable to a larger number of modes, and arbitrary spatial dimensions. PMID:26153660
Delay modeling and glitch estimation for CMOS circuits
Shiau, Yan-Chyuan
1988-01-01
the timing delay. 15 CHAPTER IV CAPACITANCE MODELING 4. 1 Units Used in Project The timing library I construct is based on the MOSIS CMOS 3prn processing parameters. Some important units are defined as following that will be used in this project: Time... CMOS process and simulate the output response by running SPICE. If we use different tool based on different technologies to calculate timing response, we may get distinct result dued to separate device parameters. 4. 3. 2 Circuit Structure A node...
A statistical MOSFET modeling method for CMOS integrated circuit simulation
Chen, Jian
1992-01-01
riw = cir. /(sisr), or X:, ", (z. , ? 22)(x, s ? rs) r1k- (n ? 1)s, ss (2 4) It is clear from equations (2. 3) and (2. 4) that crt = cir, r po = r, s and res = 1. The correlation coefficient approaches 1. 0 (or -1. 0) when a, strong positive (or... PARAMETER VARIATIONS IN CMOS CIR- CIJITS A. IC Simulation and Statistical Model . B. Basic Characterizations of Multivariate Populations C, Parameter Standardization and Scaling D. Transistor Parameter Variations in CMOS Circuits 3 4 6 8 8 8 11...
Data Mining Approaches for Modeling Complex Electronic Circuit Design Activities
Kwon, Yongjin [Ajou University, Suwon, South Korea; Omitaomu, Olufemi A [ORNL; Wang, Gi-Nam [Ajou University, Suwon, South Korea
2008-01-01
A printed circuit board (PCB) is an essential part of modern electronic circuits. It is made of a flat panel of insulating materials with patterned copper foils that act as electric pathways for various components such as ICs, diodes, capacitors, resistors, and coils. The size of PCBs has been shrinking over the years, while the number of components mounted on these boards has increased considerably. This trend makes the design and fabrication of PCBs ever more difficult. At the beginning of design cycles, it is important to estimate the time to complete the steps required accurately, based on many factors such as the required parts, approximate board size and shape, and a rough sketch of schematics. Current approach uses multiple linear regression (MLR) technique for time and cost estimations. However, the need for accurate predictive models continues to grow as the technology becomes more advanced. In this paper, we analyze a large volume of historical PCB design data, extract some important variables, and develop predictive models based on the extracted variables using a data mining approach. The data mining approach uses an adaptive support vector regression (ASVR) technique; the benchmark model used is the MLR technique currently being used in the industry. The strengths of SVR for this data include its ability to represent data in high-dimensional space through kernel functions. The computational results show that a data mining approach is a better prediction technique for this data. Our approach reduces computation time and enhances the practical applications of the SVR technique.
Improvement of magnetic circuit in levitation system using HTS and soft magnetic material
Mojtaba Ghodsi; Toshiyuki Ueno; Toshiro Higuchi
2005-01-01
This paper presents improvement of a novel levitation system in which soft magnetic material can be levitated by high-temperature superconductor (HTS). The levitation system consists of two permanent magnets, HTS samples of Dy1Ba2Cu3Oy (DBCO), and movable yoke with cylindrical parts to which trapped flux in the HTS is gathered and produces an attractive force. The attractive force generally increases with
Simulations of magnetic field gradients due to micro-magnets on a triple quantum dot circuit
Poulin-Lamarre, G. [National Research Council of Canada, Ottawa, On., Canada, K1A-0R6 and Département de physique, Université de Sherbrooke, Sherbrooke, Qc. J1K-2R1 (Canada); Bureau-Oxton, C. [Département de physique, Université de Sherbrooke, Sherbrooke, Qc. J1K-2R1 (Canada); Kam, A. [National Research Council of Canada, Ottawa, On. K1A-0R6 (Canada); Zawadzki, P.; Aers, G. [National Research Council of Canada, Ottawa, On. K1A-0R6 (Canada); Studenikin, S. [National Research Council of Canada, Ottawa, On.K1A-0R6 (Canada); Pioro-Ladrière, M. [Département de physique, Université de Sherbrooke, Sherbrooke, Qc. J1K-2R1 (Canada); Sachrajda, A. S. [National Research Council of Canada, Ottawa, On., Canada, K1A-0R6 and Département de physique, Université de Sherbrooke, Sherbrooke, Qc. J1K-2R1 (Canada)
2013-12-04
To quantify the effects of local magnetic fields on triple quantum dots, the Heisenberg Hamiltonian has been diagonalized for three electrons coupled via the exchange interaction. In particular, we have investigated different geometries of micro-magnets located on top of the triple dot in order to optimize the field gradient characteristics. In this paper, we focus on two geometries which are candidates for an addressable EDSR triple quantum dot device.
Maxwell's fluid model of magnetism
Robert Brady; Ross Anderson
2015-02-20
In 1861, Maxwell derived two of his equations of electromagnetism by modelling a magnetic line of force as a `molecular vortex' in a fluid-like medium. Later, in 1980, Berry and colleagues conducted experiments on a `phase vortex', a wave geometry in a fluid which is analogous to a magnetic line of force and also exhibits behaviour corresponding to the quantisation of magnetic flux. Here we unify these approaches by writing down a solution to the equations of motion for a compressible fluid which behaves in the same way as a magnetic line of force. We then revisit Maxwell's historical inspiration, namely Faraday's 1846 model of light as disturbances in lines of force. Using our unified model, we show that such disturbances resemble photons: they are polarised, absorbed discretely, obey Maxwell's full equations of electromagnetism to first order, and quantitatively reproduce the correlation that is observed in the Bell tests.
Delay modeling of bipolar ECL/EFL (Emitter-Coupled Logic/Emitter-Follower-Logic) circuits
NASA Astrophysics Data System (ADS)
Yang, Andrew T.
1986-08-01
This report deals with the development of a delay-time model for timing simulation of large circuits consisting of Bipolar ECL(Emitter-Coupled Logic) and EFL (Emitter-Follower-Logic) networks. This model can provide adequate information on the performance of the circuits with a minimum expenditure of computation time. This goal is achieved by the use of proper circuit transient models on which analytical delay expressions can be derived with accurate results. The delay-model developed in this report is general enough to handle complex digital circuits with multiple inputs or/and multiple levels. The important effects of input slew rate are also included in the model.
Lunar magnetism. [primordial core model
NASA Technical Reports Server (NTRS)
Goldstein, M. L.
1975-01-01
It is shown, for a very simple model of the moon, that the existence of a primordial core magnetic field would give rise to a present day nonzero dipole external field. In the investigation a uniformly magnetized core embedded in a permeable mantle is considered. The significance of the obtained results for the conclusions reported by Runcorn (1975) is discussed. Comments provided by Runcorn to the discussion are also presented.
Application of the cavity model to lossy power-return plane structures in printed circuit boards
Minjia Xu; Hao Wang; Todd H. Hubing
2003-01-01
Power-return plane pairs in printed circuit boards are often modeled as resonant cavities. Cavity models can be used to calculate transfer impedance parameters used to predict levels of power bus noise. Techniques for applying the cavity model to lossy printed circuit board geometries rely on a low-loss assumption in their derivations. Boards that have been designed to damp power bus
Doboli, Simona
Extraction of Piecewise-Linear Analog Circuit Models from Trained Neural Networks using HiddenÂ¡ @ece.sunysb.edu Abstract This paper presents a new technique for automatically creating analog circuit models. The method extracts - from trained neural networks - piecewise linear models express- ing
NASA Technical Reports Server (NTRS)
Bailey, R. F.; Reekstin, J. P.
1974-01-01
The fabrication yield of an on-chip modifiable redundant circuit design for a 100M bit serial shift register is evaluated. The yield model is a redundancy design in which there is a primary loop and a set of secondary loops which can be enabled/disabled without introducing blanks to the data stream. This function has a finite yield, the loop-modification yield factor, which must be greater than 0.9 to make the system more economical than the simple nonredundant design. It is further established that small loop capacities greatly degrade the yield because of the effect of the modification yield factor, while large loop capacities degrade the yield because of defects in the operating area. As the modification yield increases the optimum loop capacity decreases. An optimum value for the number of redundant loops exists for each loop capacity. Other factors that affect the yield are the garnet film and the processed circuit.
Robust Analog\\/RF Circuit Design With Projection-Based Performance Modeling
Padmini Gopalakrishnan; Yang Xu; Lawrence T. Pileggi; Xin Li
2007-01-01
In this paper, a robust analog design (ROAD) tool for posttuning (i.e., locally optimizing) analog\\/RF circuits is proposed. Starting from an initial design derived from hand analysis or analog circuit optimization based on simplified models, ROAD ex- tracts accurate performance models via transistor-level simulation and iteratively improves the circuit performance by a sequence of geometric programming steps. Importantly, ROAD sets
Robust analog\\/RF circuit design with projection-based posynomial modeling
Xin Li; Padmini Gopalakrishnan; Yang Xu; Lawrence T. Pileggi
2004-01-01
In this paper we propose a RObust Analog Design tool (ROAD) for post-tuning analog\\/RF circuits. Starting from an initial design derived from hand analysis or analog circuit synthesis based on simplified models, ROAD extracts accurate posynomial performance models via transistor-level simulation and optimizes the circuit by geometric programming. Importantly, ROAD sets up all design constraints to include large-scale process variations
Magnonic circuits and crystals
NASA Astrophysics Data System (ADS)
Al-Wahsh, Housni; Akjouj, Abdellatif; Djafari-Rouhani, Bahram; Dobrzynski, Leonard
2011-02-01
In the frame of the long-wavelength Heisenberg model, a simple magnonic mono-mode circuit is designed to obtain transmission stop (pass) bands where the propagation of spin waves is forbidden (allowed). This simple device is composed of an infinite one-dimensional monomode waveguide (the backbone) along which side resonators (symmetric or asymmetric loops) are grafted. These circuits are usually mono-mode when the lateral dimensions of the conducting wires are small as compared to the magnon wavelength. Their production utilizes the most advanced surface technologies and represents one of the most important challenges for the next decade. In all these circuits, the interfaces between the different wires out of which the circuits are made, play a fundamental role. All such circuits exhibit a variety of interference effects in their transport properties. Emphasis in this review article is placed on the network creations, which include stubs or resonators, closed symmetric or asymmetric loops and interconnecting branched networks. In other words, a fundamental understanding of nanoscaled materials has become an important challenge for any technical applications. For magnetic nanoparticles, the investigations are in particular stimulated by the magnetic storage devices. Then we present a theory of the magnon propagation in a quasi-one-dimensional resonant structure, composed of one nanometric magnetic cluster chain and adsorbed clusters near the chain. Results for the transmission and reflection properties of such circuits (nanometric networks) are discussed, as a function of the frequency of the excitations and the physical or geometrical properties of the circuits. In the last part of this report, we review magnonic crystals. These man-conceived materials should be useful for many applications and, in particular, for designing the mono-mode circuits reviewed in the first part of this paper. These magnonic materials and circuits may have uses for the design of integrated devices such as narrow-frequency optical or microwave filters, high-speed switches, multiplexers, storage devices, ….
YI, YM; Hu, Chia-Ren.
1992-01-01
A previous study [C.-R. Hu and C.-H. Huang, Phys. Rev. B 43, 7718 (1991)] of the phase boundary T(c)(H) of a single-cube superconducting circuit in an external magnetic field H of arbitrary magnitude and direction is extended here to superconducting...
Quantitative Modeling and Optimization of Magnetic Tweezers
Jan Lipfert; Xiaomin Hao; Nynke H. Dekker
2009-01-01
Magnetic tweezers are a powerful tool to manipulate single DNA or RNA molecules and to study nucleic acid-protein interactions in real time. Here, we have modeled the magnetic fields of permanent magnets in magnetic tweezers and computed the forces exerted on superparamagnetic beads from first principles. For simple, symmetric geometries the magnetic fields can be calculated semianalytically using the Biot-Savart
Swidzinski, Jan
1997-01-01
transistors, statistical i-nodeling techniques for integrated circuits, statistical behavioral modeling of analog functional blocks, and finally statistical behavioral system level modeling and simulation. A full statistical model for the behavioral parameters...
A functional circuit model of interaural time difference processing.
McColgan, Thomas; Shah, Sahil; Köppl, Christine; Carr, Catherine; Wagner, Hermann
2014-12-01
Inputs from the two sides of the brain interact to create maps of interaural time difference (ITD) in the nucleus laminaris of birds. How inputs from each side are matched with high temporal precision in ITD-sensitive circuits is unknown, given the differences in input path lengths from each side. To understand this problem in birds, we modeled the geometry of the input axons and their corresponding conduction velocities and latencies. Consistent with existing physiological data, we assumed a common latency up to the border of nucleus laminaris. We analyzed two biological implementations of the model, the single ITD map in chickens and the multiple maps of ITD in barn owls. For binaural inputs, since ipsi- and contralateral initial common latencies were very similar, we could restrict adaptive regulation of conduction velocity to within the nucleus. Other model applications include the simultaneous derivation of multiple conduction velocities from one set of measurements and the demonstration that contours with the same ITD cannot be parallel to the border of nucleus laminaris in the owl. Physiological tests of the predictions of the model demonstrate its validity and robustness. This model may have relevance not only for auditory processing but also for other computational tasks that require adaptive regulation of conduction velocity. PMID:25185809
An Equivalent Circuit Model for a Faraday Cage Substrate Crosstalk Isolation Structure
del Alamo, Jesús A.
An Equivalent Circuit Model for a Faraday Cage Substrate Crosstalk Isolation Structure Joyce H. Wu and Jesús A. del Alamo Massachusetts Institute of Technology, Cambridge, MA 02139, USA Abstract We have developed a physics-based equivalent circuit model for a novel Faraday cage substrate crosstalk isolation
A CIRCUIT MODEL OF QUANTUM CASCADE LASERS APPLICABLE TO BOTH SMALL AND LARGE CURRENT DRIVES
M. K. Haldar; J. F. Webb
2010-01-01
In this paper, a circuit model is devised to analyze nonlinear behaviour of quantum cascade lasers. Such nonlinear behavior influences the light output when the laser is driven by currents comparable to the average (DC) current. The simplified 2-level rate equations are first improved. Next, the circuit model is obtained following the approach for interband lasers. The difference between the
a Circuit Model of Quantum Cascade Lasers Applicable to both Small and Large Current Drives
M. K. Haldar; J. F. Webb
2010-01-01
In this paper, a circuit model is devised to analyze nonlinear behaviour of quantum cascade lasers. Such nonlinear behavior influences the light output when the laser is driven by currents comparable to the average (DC) current. The simplified 2-level rate equations are first improved. Next, the circuit model is obtained following the approach for interband lasers. The difference between the
AN INFINITE DIMENSIONAL DESCRIPTOR SYSTEM MODEL FOR ELECTRICAL CIRCUITS WITH TRANSMISSION LINES
Reis, Timo
AN INFINITE DIMENSIONAL DESCRIPTOR SYSTEM MODEL FOR ELECTRICAL CIRCUITS WITH TRANSMISSION LINES TIMO REIS Abstract. In this paper a model of linear electrical circuits with transmission lines is de-coupled with the telegraph equations who describe the behavior of the transmission lines. The resulting system of equations
W. Jin; Y. Eo; J. I. Shim; W. R. Eisenstadt; M. Y. Park; H. K. Yu
2001-01-01
The frequency-variant characteristics of a silicon substrate were physically modeled, analytically investigated, and experimentally verified. The scalable circuit model parameter extraction methodology was newly developed. Thus, the proposed technique can provides the efficient performance evaluations as well as the accurate design guidelines concerned with the complicated mixed signal integrated circuit designs
Design of energy harvester circuit for a MFC piezoelectric based on electrical circuit modeling
K. Tungpimolrut; N. Hatti; J. Phontip; K. Komoljindakul; K. Pechrach; P. Manooonpong
2011-01-01
In this paper, the characteristic of the piezoelectric material, Macro Fiber Composites (MFC), has been investigated by comparison between the electrical equivalent circuit based simulation and the experimental result. The operational factors such as internal impedance and frequency which affect the maximum power output of the piezoelectric are systematically determined. The effect from the characteristic of the capacity after the
Creating dynamic equivalent PV circuit models with impedance spectroscopy for arc-fault modeling.
Johnson, Jay Dean; Kuszmaul, Scott S.; Strauch, Jason E.; Schoenwald, David Alan
2011-06-01
Article 690.11 in the 2011 National Electrical Code{reg_sign} (NEC{reg_sign}) requires new photovoltaic (PV) systems on or penetrating a building to include a listed arc fault protection device. Currently there is little experimental or empirical research into the behavior of the arcing frequencies through PV components despite the potential for modules and other PV components to filter or attenuate arcing signatures that could render the arc detector ineffective. To model AC arcing signal propagation along PV strings, the well-studied DC diode models were found to inadequately capture the behavior of high frequency arcing signals. Instead dynamic equivalent circuit models of PV modules were required to describe the impedance for alternating currents in modules. The nonlinearities present in PV cells resulting from irradiance, temperature, frequency, and bias voltage variations make modeling these systems challenging. Linearized dynamic equivalent circuits were created for multiple PV module manufacturers and module technologies. The equivalent resistances and capacitances for the modules were determined using impedance spectroscopy with no bias voltage and no irradiance. The equivalent circuit model was employed to evaluate modules having irradiance conditions that could not be measured directly with the instrumentation. Although there was a wide range of circuit component values, the complex impedance model does not predict filtering of arc fault frequencies in PV strings for any irradiance level. Experimental results with no irradiance agree with the model and show nearly no attenuation for 1 Hz to 100 kHz input frequencies.
4th Grade Students Investigate Electric Circuits Through Construction and Illustration
NSDL National Science Digital Library
As an activity related to FOSS unit Magnetism and Electricity, 4th grade science students use a computer download to explore electrical circuits and to generate illustrations of electrical circuits for physical models built in class
Doboli, Simona
Piecewise-Linear Modeling of Analog Circuits using Trained Feed-Forward Neural Networks- ing analog circuit models. The method extracts piecewise lin- ear models from trained neural networks. A model is a set of linear dependencies between circuit performances and design parameters. The paper
A Novel Prediction Method about Single Components of Analog Circuits Based on Complex Field Modeling
Tian, Shulin; Yang, Chenglin
2014-01-01
Few researches pay attention to prediction about analog circuits. The few methods lack the correlation with circuit analysis during extracting and calculating features so that FI (fault indicator) calculation often lack rationality, thus affecting prognostic performance. To solve the above problem, this paper proposes a novel prediction method about single components of analog circuits based on complex field modeling. Aiming at the feature that faults of single components hold the largest number in analog circuits, the method starts with circuit structure, analyzes transfer function of circuits, and implements complex field modeling. Then, by an established parameter scanning model related to complex field, it analyzes the relationship between parameter variation and degeneration of single components in the model in order to obtain a more reasonable FI feature set via calculation. According to the obtained FI feature set, it establishes a novel model about degeneration trend of analog circuits' single components. At last, it uses particle filter (PF) to update parameters for the model and predicts remaining useful performance (RUP) of analog circuits' single components. Since calculation about the FI feature set is more reasonable, accuracy of prediction is improved to some extent. Finally, the foregoing conclusions are verified by experiments. PMID:25147853
Characterization and Modeling of TSV Based 3-D Integrated Circuits
community are discussed, and guidelines are provided for designing these evolving through silicon via (TSV. Finally, generation and spreading of heat in 3-D integrated circuits are discussed as part design, and DC and high frequency electrical measurements for TSV based 3-D integrated circuits. Ioannis
Bond, Bradley N.
This paper presents a system identification technique for generating stable compact models of typical analog circuit blocks in radio frequency systems. The identification procedure is based on minimizing the model error ...
Reliability-yield allocation for semiconductor integrated circuits: modeling and optimization
Ha, Chunghun
2005-11-01
This research develops yield and reliability models for fault-tolerant semiconductor integrated circuits and develops optimization algorithms that can be directly applied to these models. Since defects cause failures in microelectronics systems...
An engineering model of lower thalamo-cortico-basal ganglionic circuit function
Lim, Eugene J. (Eugene Jungsud), 1980-
2003-01-01
An engineering model of lower thalamo-cortico-basal ganglionic circuit functionality was extended and tested. This model attempts to explain the circuitry of the basal ganglia, examine its functional properties, and integrate ...
Advances in the modeling of single electron transistors for the design of integrated circuit.
Chi, Yaqing; Sui, Bingcai; Yi, Xun; Fang, Liang; Zhou, Hailiang
2010-09-01
Single electron transistor (SET) has become a promising candidate for the key device of logic circuit in the near future. The advances of recent 5 years in the modeling of SETs are reviewed for the simulation of SET/hybrid CMOS-SET integrated circuit. Three dominating SET models, Monte Carlo model, master equation model and macro model, are analyzed, tested and compared on their principles, characteristics, applicability and development trend. The Monte Carlo model is suitable for SET structure research and simulation of small scale SET circuit, while the analytical model based on combination with master equation and macro model is suitable to simulate the SET circuit at balanceable efficiency and accuracy. PMID:21133161
Modeling the dynamical effects of anesthesia on brain circuits.
Ching, Shinung; Brown, Emery N
2014-04-01
General anesthesia is a neurophysiological state that consists of unconsciousness, amnesia, analgesia, and immobility along with maintenance of physiological stability. General anesthesia has been used in the United States for more than 167 years. Now, using systems neuroscience paradigms how anesthetics act in the brain and central nervous system to create the states of general anesthesia is being understood. Propofol is one of the most widely used and the most widely studied anesthetics. When administered for general anesthesia or sedation, the electroencephalogram (EEG) under propofol shows highly structured, rhythmic activity that is strongly associated with changes in the patient's level of arousal. These highly structured oscillations lend themselves readily to mathematical descriptions using dynamical systems models. We review recent model descriptions of the commonly observed EEG patterns associated with propofol: paradoxical excitation, strong frontal alpha oscillations, anteriorization and burst suppression. Our analysis suggests that propofol's actions at GABAergic networks in the cortex, thalamus and brainstem induce profound brain dynamics that are one of the likely mechanisms through which this anesthetic induces altered arousal states from sedation to unconsciousness. Because these dynamical effects are readily observed in the EEG, the mathematical descriptions of how propofol's EEG signatures relate to its mechanisms of action in neural circuits provide anesthesiologists with a neurophysiologically based approach to monitoring the brain states of patients receiving anesthesia care. PMID:24457211
NASA Astrophysics Data System (ADS)
Yuan, Fang; Wang, Guang-Yi; Wang, Xiao-Yuan
2015-06-01
To develop real world memristor application circuits, an equivalent circuit model which imitates memductance (memory conductance) of the HP memristor is presented. The equivalent circuit can be used for breadboard experiments for various application circuit designs of memristor. Based on memductance of the realistic HP memristor and Chua’s circuit a new chaotic oscillator is designed. Some basic dynamical behaviors of the oscillator, including equilibrium set, Lyapunov exponent spectrum, and bifurcations with various circuit parameters are investigated theoretically and numerically. To confirm the correction of the proposed oscillator an analog circuit is designed using the proposed equivalent circuit model of an HP memristor, and the circuit simulations and the experimental results are given. Project supported by the National Natural Science Foundation of China (Grant Nos. 61271064 and 60971046), the Natural Science Foundation of Zhejiang Province, China (Grant No. LZ12F01001), and the Program for Zhejiang Leading Team of Science and Technology Innovation, China (Grant No. 2010R50010-07).
Modeling Magnetic Properties in EZTB
NASA Technical Reports Server (NTRS)
Lee, Seungwon; vonAllmen, Paul
2007-01-01
A software module that calculates magnetic properties of a semiconducting material has been written for incorporation into, and execution within, the Easy (Modular) Tight-Binding (EZTB) software infrastructure. [EZTB is designed to model the electronic structures of semiconductor devices ranging from bulk semiconductors, to quantum wells, quantum wires, and quantum dots. EZTB implements an empirical tight-binding mathematical model of the underlying physics.] This module can model the effect of a magnetic field applied along any direction and does not require any adjustment of model parameters. The module has thus far been applied to study the performances of silicon-based quantum computers in the presence of magnetic fields and of miscut angles in quantum wells. The module is expected to assist experimentalists in fabricating a spin qubit in a Si/SiGe quantum dot. This software can be executed in almost any Unix operating system, utilizes parallel computing, can be run as a Web-portal application program. The module has been validated by comparison of its predictions with experimental data available in the literature.
Altarawneh, M M
2012-09-01
We present a new technique to perform radio frequency (rf) contactless conductivity measurements in pulsed magnetic fields to probe different ground states in condensed matter physics. The new method utilizes a simple analog band-stop filter circuit implemented in a radio frequency transmission setup to perform contactless conductivity measurements. The new method is more sensitive than the other methods (e.g., the tunnel diode oscillator and the proximity detector oscillator) due to more sensitive dependence of the circuit resonance frequency on the tank circuit inductance (not the transmission line). More important, the new method is more robust than other methods when used to perform measurements in very high magnetic fields, works for a wide range of temperatures (i.e., 300 K-1.4 K) and is less sensitive to noise and mechanical vibrations during pulse magnet operation. The new technique was successfully applied to measure the Shubnikov-de Haas effect in Bi(2)Se(3) in pulsed magnetic fields of up to 60 T. PMID:23020430
[Modeling and analysis of volume conduction based on field-circuit coupling].
Tang, Zhide; Liu, Hailong; Xie, Xiaohui; Chen, Xiufa; Hou, Deming
2012-08-01
Numerical simulations of volume conduction can be used to analyze the process of energy transfer and explore the effects of some physical factors on energy transfer efficiency. We analyzed the 3D quasi-static electric field by the finite element method, and developed A 3D coupled field-circuit model of volume conduction basing on the coupling between the circuit and the electric field. The model includes a circuit simulation of the volume conduction to provide direct theoretical guidance for energy transfer optimization design. A field-circuit coupling model with circular cylinder electrodes was established on the platform of the software FEM3.5. Based on this, the effects of electrode cross section area, electrode distance and circuit parameters on the performance of volume conduction system were obtained, which provided a basis for optimized design of energy transfer efficiency. PMID:23016401
Modeling of Jitter in Bang-BangClock and Data Recovery Circuits'
Razavi, Behzad
Modeling of Jitter in Bang-BangClock and Data Recovery Circuits' Jri Lee, Kenneth S Systems,San Jose, CA Abstract This paper presents an approachto analyzing bang-bang CDR loops, predicting and data recovery (CDR) circuits incorporatingbang- bang (binary) phase detectors (PDs) have recently found
Friedrich T. Sommer; Thomas Wennekers
2000-01-01
The interplay between modelling and experimental studies can support the exploration of the function of neuronal circuits in the cortex. We exemplify such an approach with a study on the role of spike timing and gamma-oscillations in associative memory in strongly connected circuits of cortical neurones. It is demonstrated how associative memory studies on different levels of abstraction can specify
Propagation delay and short-circuit power dissipation modeling of the CMOS inverter
Labros Bisdounis; Spiridon Nikolaidis; O. Loufopavlou
1998-01-01
This paper introduces a new, accurate analytical model for the evaluation of the delay and the short-circuit power dissipation of the CMOS inverter. Following a detailed analysis of the inverter operation, accurate expressions for the output response to an input ramp are derived. Based on this analysis improved analytical formulae for the calculation of the propagation delay and short-circuit power
Log-Domain Circuit Models of Chemical Reactions Soumyajit Mandal and Rahul Sarpeshkar
Sarpeshkar, Rahul
Log-Domain Circuit Models of Chemical Reactions Soumyajit Mandal and Rahul Sarpeshkar Department to networks of chemical reactions. Our circuits can be used for transient and steady-state simulations the energy barrier of a chemical reaction, exponentially changing its speed. In an analogous fashion, gate
Modeling of Large Scale RF-MEMS Circuits Using Efficient Time-Domain Techniques
Tentzeris, Manos
Modeling of Large Scale RF-MEMS Circuits Using Efficient Time-Domain Techniques N. Bushyager, E Engineering Georgia Institute of Technology Atlanta, GA 30332-0250, USA Abstract RF-MEMS design is made difficult due to the lack of tools capable of simulating both MEMS devices and their surrounding circuits
Basic neuron model electrical equivalent circuit: an undergraduate laboratory exercise.
Dabrowski, Katie M; Castaño, Diego J; Tartar, Jaime L
2013-01-01
We developed a hands-on laboratory exercise for undergraduate students in which they can build and manipulate a neuron equivalent circuit. This exercise uses electrical circuit components that resemble neuron components and are easy to construct. We describe the methods for creating the equivalent circuit and how to observe different neuron properties through altering the structure of the equivalent circuit. We explain how this hands-on laboratory activity allows for the better understanding of this fundamental neuroscience concept. At the conclusion of this laboratory exercise, undergraduate students will be able to apply the principles of Ohm's law, cable theory with regards to neurons, and understand the functions of resistance and capacitance in a neuron. PMID:24319391
Astrocyte regulation of sleep circuits: experimental and modeling perspectives
Halassa, Michael M.
Integrated within neural circuits, astrocytes have recently been shown to modulate brain rhythms thought to mediate sleep function. Experimental evidence suggests that local impact of astrocytes on single synapses translates ...
Log-domain circuit models of chemical reactions
Mandal, Soumyajit
We exploit the detailed similarities between electronics and chemistry to develop efficient, scalable bipolar or subthreshold log-domain circuits that are dynamically equivalent to networks of chemical reactions. Our ...
Advanced modeling of planarization processes for integrated circuit fabrication
Fan, Wei, Ph. D. Massachusetts Institute of Technology
2012-01-01
Planarization processes are a key enabling technology for continued performance and density improvements in integrated circuits (ICs). Dielectric material planarization is widely used in front-end-of-line (FEOL) processing ...
Three-Dimensional Electro-Thermal Verilog-A Model of Power MOSFET for Circuit Simulation
NASA Astrophysics Data System (ADS)
Chvála, A.; Donoval, D.; Marek, J.; Príbytný, P.; Molnár, M.; Mikolášek, M.
2014-04-01
New original circuit model for the power device based on interactive coupling of electrical and thermal properties is described. The thermal equivalent network for a three-dimensional heat flow is presented. Designed electro-thermal MOSFET model for circuit simulations with distributed properties and three-dimensional thermal equivalent network is used for simulation of multipulse unclamped inductive switching (UIS) test of device robustness. The features and the limitations of the new model are analyzed and presented.
NASA Astrophysics Data System (ADS)
Jazebi, Saeed
This thesis is a step forward toward achieving the final objective of creating a fully dual model for transformers including eddy currents and nonlinearities of the iron core using the fundamental electrical components already available in the EMTP-type programs. The model is effective for the study of the performance of transformers during power system transients. This is very important for transformer designers, because the insulation of transformers is determined with the overvoltages caused by lightning or switching operations. There are also internally induced transients that occur when a switch is actuated. For example switching actions for reconfiguration of distribution systems that offers economic advantages, or protective actions to clear faults and large short-circuit currents. Many of the smart grid concepts currently under development by many utilities rely heavily on switching to optimize resources that produce transients in the system. On the other hand, inrush currents produce mechanical forces which deform transformer windings and cause malfunction of the differential protection. Also, transformer performance under ferroresonance and geomagnetic induced currents are necessary to study. In this thesis, a physically consistent dual model applicable to single-phase two-winding transformers is proposed. First, the topology of a dual electrical equivalent circuit is obtained from the direct application of the principle of duality. Then, the model parameters are computed considering the variations of the transformer electromagnetic behavior under various operating conditions. Current modeling techniques use different topological models to represent diverse transient situations. The reversible model proposed in this thesis unifies the terminal and topological equivalent circuits. The model remains invariable for all low-frequency transients including deep saturation conditions driven from any of the two windings. The very high saturation region of the iron core magnetizing characteristic is modified with the accurate measurement of the air-core inductance. The air-core inductance is measured using a non-ideal low-power rectifier. Its dc output serves to drive the transformer into deep saturation, and its ripple provides low-amplitude variable excitation. The principal advantage of this method is its simplicity. To model the eddy current effects in the windings, a novel equivalent circuit is proposed. The circuit is derived from the principle of duality and therefore, matches the electromagnetic physical behavior of the transformer windings. It properly models the flux paths and current distribution from dc to MHz. The model is synthesized from a non-uniform concentric discretization of the windings. Concise guidelines are given to optimally calculate the width of the sub-divisions for various transient simulations. To compute the circuit parameters only information about the geometry of the windings and about their material properties is needed. The calculation of the circuit parameters does not require an iterative process. Therefore, the parameters are always real, positive, and free from convergence problems. The proposed model is tested with single-phase transformers for the calculation of magnetizing inrush currents, series ferroresonance, and Geomagnetic Induced Currents (GIC). The electromagnetic transient response of the model is compared to laboratory measurements for validation. Also, 3D finite element simulations are used to validate the electromagnetic behavior of the transformer model. Large manufacturer of transformers, power system designers, and electrical utility companies can benefit from the new model. It simplifies the design and optimization of the transformers' insulation, thereby reducing cost, and enhancing reliability of the system. The model could also be used for inrush current and differential protection studies, geomagnetic induced current studies, harmonic penetration studies, and switching transient studies.
Modelling of transpositions and double circuit transmission lines in switching surge calculations
A. Dabuleanu; A. Semlyen
1975-01-01
The paper extends the method of recursive convolutions for the calculation of electro-magnetic transients on transmission lines with ground return to discretely transposed lines and double circuit lines. A review of the recursive convolution method is first given, completed with a starting procedure for the calculation of transients from a known steady state. Effects of transpositions, such as mode reflections
Tosi, Guilherme, E-mail: g.tosi@unsw.edu.au; Mohiyaddin, Fahd A.; Morello, Andrea, E-mail: a.morello@unsw.edu.au [Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, UNSW Australia, Sydney, New South Wales 2052, Australia. (Australia); Huebl, Hans [Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, D-85748 Garching (Germany); Nanosystems Initiative Munich (NIM), Schellingstr. 4, D-80799 Munich, Germany. (Germany)
2014-08-15
Recent advances in silicon nanofabrication have allowed the manipulation of spin qubits that are extremely isolated from noise sources, being therefore the semiconductor equivalent of single atoms in vacuum. We investigate the possibility of directly coupling an electron spin qubit to a superconducting resonator magnetic vacuum field. By using resonators modified to increase the vacuum magnetic field at the qubit location, and isotopically purified {sup 28}Si substrates, it is possible to achieve coupling rates faster than the single spin dephasing. This opens up new avenues for circuit-quantum electrodynamics with spins, and provides a pathway for dispersive read-out of spin qubits via superconducting resonators.
Saturation Core Modeling Procedure for Magnetic Components using Finite Element Analysis
R. A. Salas; J. Pleite; C. Gonzalez; V. Valdivia
2007-01-01
The aim of this article is the experimental verification of a procedure for modeling magnetic components using finite element analysis (FEA). In this procedure the core saturation effect is taken into account and is designed for use in a commercial circuit simulator. The verification was carried out for a core ferrite, which is used in power electronics. It was specifically
Bridging the gap between FEA field solution and the magnetic component model
R. Prieto; R. Asensi; C. Fernandez; J. A. Cobos
2005-01-01
The use of FEA solvers in order to explore the field distribution is a common practice for designing custom made magnetic components. However, the levering of the field distribution information to the generation of a model valid to be simulated in a circuit simulator is not evident. There are several issues that need to be addressed in order to obtain
Bridging the Gap Between FEA Field Solution and the Magnetic Component Model
Roberto Prieto; Rafael Asensi; Cristina Fernández; J. A. Oliver; J. A. Cobos
2007-01-01
The use of finite element analysis (FEA) solvers in order to explore the field distribution is a common practice for designing custom made magnetic components. However, the use of the field distribution information for the generation of a model valid to be simulated in a circuit simulator is not evident. There are several issues that need to be addressed in
Characteristics and computer model simulation of magnetic damping forces in maglev systems
J. L. He; D. M. Rote; S. S. Chen
1994-01-01
This report discusses the magnetic damping force in electrodynamic suspension (EDS) maglev systems. The computer model simulations, which combine electrical system equations with mechanical motion equations on the basis of dynamic circuit theory, were conducted for a loop-shaped coil guideway. The intrinsic damping characteristics of the EDS-type guideway are investigated, and the negative damping phenomenon is confirmed by the computer
ANN\\/DNN-Based Behavioral Modeling of RF\\/Microwave Components and Circuits
Q. J. Zhang; Lei Zhang
\\u000a This paper provides a tutorial overview of artificial neural network\\/ dynamic neural network (ANN\\/DNN) for radio frequency\\u000a (RF) and microwave modeling and design. We will describe neural network structures suitable for representing high-speed\\/high-frequency\\u000a behaviors in components and circuits, ANN training exploiting RF\\/microwave device and circuit data, formulation of ANN\\/DNN\\u000a for microwave component and circuit behavioral modeling, and use of ANN\\/DNN
Fast behavioral modeling of organic CMOS devices for digital and analog circuit applications
NASA Astrophysics Data System (ADS)
Jacob, Stephanie; Daami, Anis; Gwoziecki, Romain; Coppard, Romain; Hamani, Rachid; Guerin, Mathieu; Bergeret, Emmanuel; Pannier, Philippe
2011-10-01
Organic thin film technologies have opened a new range of interest into the optoelectronics industry. Nevertheless the physics and devices modeling still present a lack of accuracy. In order to provide designers with the latest performances of our organic CMOS technology, we have compared the performances of a behavioral model to the public a-Si TFT model in terms of accuracy on device modeling and basic circuit simulations. Fully printed organic CMOS devices and circuits have been processed and characterized in order to validate our device models. In particular, measurements have been carried out on several digital circuits like inverters and ring oscillators. Analog circuits such as current mirrors and differential pairs have also been measured. Simulations of these circuits have been performed using the device behavioral model and the a-Si TFT one under common EDA commercial tools. We show that both kinds of models enable to reproduce the different simple CMOS circuits performances in static as well as in dynamic modes which can open the way for designing a wide range and more complex digital and analog organic applications.
Modelling of bulk superconductor magnetization
Ainslie, M. D.; Fujishiro, H.
2015-03-30
bearings, energy storage flywheels, magnetic resonance imaging, magnetic separation and rotating machines [24-26]. Significantly, the higher magnetic loading in rotating machines would provide an increased torque/power density, resulting potentially in a...
From Boolean Network Model to Continuous Model Helps in Design of Functional Circuits
Zhang, Dongliang; Wu, Jiayi; Ouyang, Qi
2015-01-01
Computational circuit design with desired functions in a living cell is a challenging task in synthetic biology. To achieve this task, numerous methods that either focus on small scale networks or use evolutionary algorithms have been developed. Here, we propose a two-step approach to facilitate the design of functional circuits. In the first step, the search space of possible topologies for target functions is reduced by reverse engineering using a Boolean network model. In the second step, continuous simulation is applied to evaluate the performance of these topologies. We demonstrate the usefulness of this method by designing an example biological function: the SOS response of E. coli. Our numerical results show that the desired function can be faithfully reproduced by candidate networks with different parameters and initial conditions. Possible circuits are ranked according to their robustness against perturbations in parameter and gene expressions. The biological network is among the candidate networks, yet novel designs can be generated. Our method provides a scalable way to design robust circuits that can achieve complex functions, and makes it possible to uncover design principles of biological networks. PMID:26061094
Modeling of three dimensional defects in integrated circuits
Dani, Sameer Manohar
1993-01-01
. 27 Hacking of adjacent sites for rectangles 1, 2, 3, 4 of layer A and 5, 6, 7 of layer B. Two intersecting volumes. CPU time versus number of rectangles. X]1 FIGURE Page 30 Layout ol a, circuit used for displaying critical regions. 51 31... and consequently is unsuitable for analyzing large layouts. IFA [12] is an another statistical tool, which for various defect sizes can predict realistic faults given the layout of any circuit. 2. Analytical: RYE [13] is an acronym for Realistic Yield...
Magnetic field properties of SSC model dipole magnets
Wake, M.; Bossert, R.; Carson, J.; Delchamps, S.; Jaffery, T.S.; Kinney, W.; Koska, W.; Lamm, M.J.; Strait, J. (Fermi National Accelerator Lab., Batavia, IL (United States)); Butteris, J.; Sims, R.; Winters, M. (Superconducting Super Collider Lab., Dallas, TX (United States))
1992-09-01
SSC 1.5m model dipole magnets were built and tested at Fermilab. Magnetic field properties were studied in term of transfer function variation and multipole components. The results were satisfactory. Observation of periodicity of remanent field along the axis is also reported.
Middle school students' mental models of magnets and magnetism
NASA Astrophysics Data System (ADS)
Sederberg, David
The purpose of this study was to conduct a detailed analysis of students' mental models across three themes related to magnetism: what magnets are, what it means to be magnetized, and how magnetic interactions occur. Mental models are organized collections of conceptions, run in one's mind, to help understand the world (Johnson-Laird, 1983). They also provide the learner a means to organize concepts in a way to help understand the world or to explain it to others (Clement & Sarama, 2004; Harrison & Treagust, 1996). While there has been considerable prior research documenting students' conceptions related to magnetism, the majority of the studies comprising this informative and valuable body of work has been confined to specific concepts at points in time. Comparatively, few studies have examined how students make sense of multiple concepts relating to magnetism and how the sophistication and explanatory power of their mental models comprised of these concepts change with instruction. Using an interpretive research design, the goal here was not to count concepts or individuals' representations of them, but rather to qualitatively search for patterns in representations of students' conceptions and lines of reasoning that are indicative of broader interpretations of experience (Strauss & Corbin, 1998) - students' mental models relating to magnetism. Using a variety of methods of elicitation, including free response items prior to and throughout instruction and semi-structured interviews, I identified five categories of concepts from which students constructed their mental models: (1) material-based properties; (2) two-sidedness; (3) internal features; (4) organization; and (5) external spatial features. Analysis of the representation of concepts among these categories yielded five levels of mental models based on model sophistication and ability to explain magnetic phenomena across diverse contexts. Results suggested that through explicitly scaffolded instruction based on a small number of fundamental principles, 8th grade students were able to construct level-appropriate microscale-based mental models of magnetic phenomena.
NASA Astrophysics Data System (ADS)
>Oon Kheng Heong,
2013-06-01
There are various types of UWB antennas can be used to scavenge energy from the air and one of them is the printed disc monopole antenna. One of the new challenges imposed on ultra wideband is the design of a generalized antenna circuit model. It is developed in order to extract the inductance and capacitance values of the UWB antennas. In this research work, the developed circuit model can be used to represent the rectangular printed disc monopole antenna with double steps. The antenna structure is simulated with CST Microwave Studio, while the circuit model is simulated with AWR Microwave Office. In order to ensure the simulation result from the circuit model is accurate, the circuit model is also simulated using Mathlab program. The developed circuit model is found to be able to depict the actual UWB antenna. Energy harvesting from environmental wirelessly is an emerging method, which forms a promising alternative to existing energy scavenging system. The developed UWB can be used to scavenge wideband energy from electromagnetic wave present in the environment.
Modeling and magnetic measurements of TNK synchrotron radiation source magnets
NASA Astrophysics Data System (ADS)
Belokrinitsky, S.; Churkin, I.; Oleynik, A.; Pekshev, D.; Philipchenko, A.; Rouvinsky, I.; Steshov, A.; Ushakov, V.
2009-05-01
The TNK synchrotron radiation source is being built by Budker Institute of Nuclear Physics on the base of Lukin State Research Institute of Physical Problems. Magnetic system for the storage ring of TNK synchrotron radiation source was produced at the BINP. It consists of 6 superperiods and includes 24 dipole magnets, 72 quadrupole lenses, 36 sextupole lenses and 12 octupole lenses.The storage ring will operate in a wide range of energies—from 450 to 2200 MeV—which corresponds to 0.3-1.5 T magnetic field in dipole magnets. Dipole magnets have H-shape solid yokes from Armco iron with a curved form. Dipole gap is 42 mm and yoke straight length is 1447 mm. The results of 3D magnetic field modeling executed by means of Mermaid 3D are presented. All dipole magnets were magnetically measured by special Hall probe measurement system developed in BINP. The results of magnetic measurements and modeling are compared and analyzed.
Modeling and Fabrication of Micro FET Pressure Sensor with Circuits
Dai, Ching-Liang; Tai, Yao-Wei; Kao, Pin-Hsu
2007-01-01
This paper presents the simulation, fabrication and characterization of a micro FET (field effect transistor) pressure sensor with readout circuits. The pressure sensor includes 16 sensing cells in parallel. Each sensing cell that is circular shape is composed of an MOS (metal oxide semiconductor) and a suspended membrane, which the suspended membrane is the movable gate of the MOS. The CoventorWare is used to simulate the behaviors of the pressure sensor, and the HSPICE is employed to evaluate the characteristics of the circuits. The pressure sensor integrated with circuits is manufactured using the commercial 0.35 ?m CMOS (complementary metal oxide semiconductor) process and a post-process. In order to obtain the suspended membranes, the pressure sensor requires a post-CMOS process. The post-process adopts etchants to etch the sacrificial layers in the pressure sensors to release the suspended membranes, and then the etch holes in the pressure sensor are sealed by LPCVD (low pressure chemical vapor deposition) parylene. The pressure sensor produces a change in current when applying a pressure to the sensing cells. The circuits are utilized to convert the current variation of the pressure sensor into the voltage output. Experimental results show that the pressure sensor has a sensitivity of 0.032 mV/kPa in the pressure range of 0-500 kPa.
Equivalent circuit modeling of hybrid electric vehicle drive train
Routex, Jean-Yves
2001-01-01
this objective, a methodology based on electrical analogies and transducers theory is presented in this work. Using the powerful circuit theory to solve multi-disciplinary problems is not revolutionary, but applied to the design of advanced vehicles, it brings a...
The Dynamics of Associative Learning in Evolved Model Circuits
Beer, Randall D.
Western Reserve University, Cleveland, OH 44106 2 Departments of Biology, Neurosciences, and Biomedical of Computer Science, Department of Informatics, Indiana University, Bloomington, IN 47406 In this article, we our experimental design. Next, we describe the evolution of nonplastic neural circuits that can solve
None
2012-01-09
GENI Project: General Atomics is developing a direct current (DC) circuit breaker that could protect the grid from faults 100 times faster than its alternating current (AC) counterparts. Circuit breakers are critical elements in any electrical system. At the grid level, their main function is to isolate parts of the grid where a fault has occurred—such as a downed power line or a transformer explosion—from the rest of the system. DC circuit breakers must interrupt the system during a fault much faster than AC circuit breakers to prevent possible damage to cables, converters and other grid-level components. General Atomics’ high-voltage DC circuit breaker would react in less than 1/1,000th of a second to interrupt current during a fault, preventing potential hazards to people and equipment.
NASA Astrophysics Data System (ADS)
Li, Dandan; Liu, Fugui; Li, Yongjian; Zhao, Zhigang; Zhang, Changgeng; Yang, Qingxin
2014-05-01
A 2-D vector hybrid hysteresis model for a soft magnetic composite (SMC) material is established, which is combined with classical Preisach model and Stoner-Wohlfarth (S-W) model. The rotational magnetic properties of SMC materials were studied using the vector model, and the computed results were compared with the experimental measurement. It is shown that the vector hybrid model can effectively simulate the rotational magnetic properties under low magnetization fields.
Mathematical modelling of transformer sheet steel magnetization
NASA Astrophysics Data System (ADS)
Jagie??o, A. St.
1996-07-01
A mathematical model for magnetizing ferromagnetic materials in sheet form is presented. The equations presented constitute a mathematical description of the processes occurring during magnetization by an external, uniform, planar magnetic field parallel to the sheet surface. With regard to the energy balance, the eddy current losses permit us to analyse the dynamic features of the hysteresis loop.
Quantum game simulator, using the circuit model of quantum computation
NASA Astrophysics Data System (ADS)
Vlachos, Panagiotis; Karafyllidis, Ioannis G.
2009-10-01
We present a general two-player quantum game simulator that can simulate any two-player quantum game described by a 2×2 payoff matrix (two strategy games).The user can determine the payoff matrices for both players, their strategies and the amount of entanglement between their initial strategies. The outputs of the simulator are the expected payoffs of each player as a function of the other player's strategy parameters and the amount of entanglement. The simulator also produces contour plots that divide the strategy spaces of the game in regions in which players can get larger payoffs if they choose to use a quantum strategy against any classical one. We also apply the simulator to two well-known quantum games, the Battle of Sexes and the Chicken game. Program summaryProgram title: Quantum Game Simulator (QGS) Catalogue identifier: AEED_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEED_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 3416 No. of bytes in distributed program, including test data, etc.: 583 553 Distribution format: tar.gz Programming language: Matlab R2008a (C) Computer: Any computer that can sufficiently run Matlab R2008a Operating system: Any system that can sufficiently run Matlab R2008a Classification: 4.15 Nature of problem: Simulation of two player quantum games described by a payoff matrix. Solution method: The program calculates the matrices that comprise the Eisert setup for quantum games based on the quantum circuit model. There are 5 parameters that can be altered. We define 3 of them as constant. We play the quantum game for all possible values for the other 2 parameters and store the results in a matrix. Unusual features: The software provides an easy way of simulating any two-player quantum games. Running time: Approximately 0.4 sec (Region Feature) and 0.3 sec (Payoff Feature) on a Intel Core 2 Duo GHz with 2 GB of memory under Windows XP.
Analytical model for permanent magnet motors with surface mounted magnets
A. B. Proca; A. Keyhani; A. El-Antably; Wenzhe Lu; Min Dai
2003-01-01
This paper presents an analytical method of modeling permanent magnet (PM) motors. The model is dependent only on geometrical and materials data which makes it suitable for insertion into design programs, avoiding long finite element analysis (FEA) calculations. The modeling procedure is based on the calculation of the air gap field density waveform at every time instant. The waveform is
Quasi-linear vacancy dynamics modeling and circuit analysis of the bipolar memristor.
Abraham, Isaac
2014-01-01
The quasi-linear transport equation is investigated for modeling the bipolar memory resistor. The solution accommodates vacancy and circuit level perspectives on memristance. For the first time in literature the component resistors that constitute the contemporary dual variable resistor circuit model are quantified using vacancy parameters and derived from a governing partial differential equation. The model describes known memristor dynamics even as it generates new insight about vacancy migration, bottlenecks to switching speed and elucidates subtle relationships between switching resistance range and device parameters. The model is shown to comply with Chua's generalized equations for the memristor. Independent experimental results are used throughout, to validate the insights obtained from the model. The paper concludes by implementing a memristor-capacitor filter and compares its performance to a reference resistor-capacitor filter to demonstrate that the model is usable for practical circuit analysis. PMID:25390634
Quasi-Linear Vacancy Dynamics Modeling and Circuit Analysis of the Bipolar Memristor
Abraham, Isaac
2014-01-01
The quasi-linear transport equation is investigated for modeling the bipolar memory resistor. The solution accommodates vacancy and circuit level perspectives on memristance. For the first time in literature the component resistors that constitute the contemporary dual variable resistor circuit model are quantified using vacancy parameters and derived from a governing partial differential equation. The model describes known memristor dynamics even as it generates new insight about vacancy migration, bottlenecks to switching speed and elucidates subtle relationships between switching resistance range and device parameters. The model is shown to comply with Chua's generalized equations for the memristor. Independent experimental results are used throughout, to validate the insights obtained from the model. The paper concludes by implementing a memristor-capacitor filter and compares its performance to a reference resistor-capacitor filter to demonstrate that the model is usable for practical circuit analysis. PMID:25390634
NASA Astrophysics Data System (ADS)
Sakimura, N.; Nebashi, R.; Natsui, M.; Ohno, H.; Sugibayashi, T.; Hanyu, T.
2014-05-01
This paper describes the possibility of a switching upset of a magnetic tunnel junction (MTJ) caused by a terrestrial radiation-induced single-event-upset (SEU) current in spintronic integrated circuits. The current waveforms were simulated by using a 3-D device simulator in a basic circuit including MTJs designed using 90-nm CMOS parameters and design rules. The waveforms have a 400 -?A peak and a 200-ps elapsed time when neutron particles with a linear energy transfer value of 14 MeV cm2/mg enter the silicon surface. The authors also found that the SEU current may cause soft errors with a probability of more than 10-12 per event, which was obtained by approximate solution of the ordinary differential equation of switching probability when the intrinsic critical current (IC0) became less than 30 ?A.
Use of magnetic modeling for measurement of space distribution of electrostatic-field strength
Skachkov, S.V.
1988-08-01
A method for magnetic modeling of an electrostatic field is described. The interpolar gap of the model magnet is constructed to ensure geometric similarity with respect to the gap of the electrostatic device under study. Surfaces with electrostatic potentials U/sub i/= const are modeled by surfaces of iron poles and magnetic circuits with magnetic potentials psi/sub i/ = const, which are proportional to the corresponding U/sub i/. The magnetic induction B(x, y, z), which is measured by conventional methods with an accuracy of approx. = 0.5%, serves as an analog of the field E(x, y, z) under study. Experiments in modeling of one of the ion injectors considered for the proton/heavy ion accelerator system of the Institute of Theoretical and Experimental Physics are examined as an application of the method.
Stepwise quadratic state-space modeling technique for simulation of power electronics circuits
K. K. Tse; Henry Shu-hung Chung; S. Y. R. Hui
1999-01-01
A fast and accurate technique for simulation of power electronics circuits is presented. The methodology begins by using Chebyshev polynomials to derive an adaptive stepwise quadratic state-space model for each piecewise-linear circuit topology. The state-space equation sets are integrated with modified nodal equations. The key feature of this algorithm is that it gives an approximate value of the optimum simulation
Functional Model of Carbon Nanotube Programmable Resistors for Hybrid Nano\\/CMOS Circuit Design
Weisheng Zhao; Guillaume Agnus; Vincent Derycke; Ariana Filoramo; Christian Gamrat; Jean-Philippe Bourgoin
2009-01-01
Hybrid Nano (e.g. Nanotube and Nanowire) \\/CMOS circuits combine both the advantages of Nano-devices and CMOS technologies;\\u000a they have thus become the most promising candidates to relax the intrinsic drawbacks of CMOS circuits beyond Moore’s law.\\u000a A functional simulation model for an hybrid Nano\\/CMOS design is presented in this paper. It is based on Optically Gated Carbon\\u000a NanoTube Field Effect
NASA Astrophysics Data System (ADS)
Iezekiel, Stavros; Christou, Andreas
2015-03-01
Equivalent circuit models of a transistor laser are used to investigate the suitability of this relatively new device for analog microwave photonic links. The three-terminal nature of the device enables transistor-based circuit design techniques to be applied to optoelectronic transmitter design. To this end, we investigate the application of balanced microwave amplifier topologies in order to enable low-noise links to be realized with reduced intermodulation distortion and improved RF impedance matching compared to conventional microwave photonic links.
Simulation with power circuit by modeling of plasmas within bubble in water
NASA Astrophysics Data System (ADS)
Obo, Hayato; Takeuchi, Nozomi; Yasuoka, Koichi
2014-10-01
Plasma is used in water treatments such as the decomposition of persistent compounds and the generation of chemically active species. We have developed a new plasma reactor with 21 treatment holes and successfully achieved the decomposition of organofluoric compounds by generating 21 plasmas in water. The equivalent circuit model of plasma within bubbles in water consists of plasma and water resistance. A typical plasma model consists of a Zener diode and cannot be used to express the transient state of plasma. In the Zener diode model, therefore, plasma cannot be simulated with a power circuit. In this work, we have developed a new equivalent circuit that consists of an ideal switch, a diode, and water resistance to model the plasma. With the circuit elements used in our model, it is possible to perform simulation of plasmas by modeling the generation as well as the extinction of plasma with a high voltage power circuit. We confirmed that the simulated voltage and current waveforms of the reactor were coincident with the experimental result by applying the variation of a plasma parameter in the plasma model.
A proper model for the partitioning of electrical circuits
D. G. Schweikert; B. W. Kernighan
1972-01-01
Partitioning algorithms for electrical circuits are often based on the heuristic manipulation of a simple element-to-element interconnection matrix. However, the element-to-element interconnection matrix does not properly represent an electrical interconnection, or “net”, among more than two elements. This paper expands on several aspects of the discrepancy: 1) its source, 2) the circumstances under which it is likely to be significant,
Simple electronic circuit model for doubly stochastic resonance.
Zaikin, A A; Murali, K; Kurths, J
2001-02-01
We have recently reported the phenomenon of doubly stochastic resonance [Phys. Rev. Lett. 85, 227 (2000)], a synthesis of noise-induced transition and stochastic resonance. The essential feature of this phenomenon is that multiplicative noise induces a bimodality and additive noise causes stochastic resonance behavior in the induced structure. In the present paper we outline possible applications of this effect and design a simple lattice of electronic circuits for the experimental realization of doubly stochastic resonance. PMID:11308450
Magnetic field diffusion modeling of a small enclosed firing system
Warne, L.K.; Merewether, K.O.
1996-01-01
Intense magnetic fields exist in the immediate vicinity of a lightning strike (and near power lines). Conducting barriers increase the rise time (and thus decrease the rise rate) interior to the barrier, but typically do not prevent penetration of the magnetic field, since the lightning current fall time may be larger than the barrier diffusion time. Thus, substantial energy is present in the interior field, although the degradation of rise rate makes it more difficult to couple into electrical circuits. This report assesses the threat posed by the diffusive magnetic field to interior components and wire loops (where voltages are induced). Analytical and numerical bounding analyses are carried out on a pill box shaped conducting barrier to develop estimates for the worst case magnetic field threats inside the system. Worst case induced voltages and energies are estimated and compared with threshold charge voltages and energies on the output capacitor of the system. Variability of these quantities with respect to design parameters are indicated. The interior magnetic field and induced voltage estimates given in this report can be used as excitations for more detailed interior and component models.
Weissbach, R.S.; Karady, G.G.; Farmer, R.G. [Arizona State Univ., Tempe, AZ (United States)
1996-11-01
A flywheel energy storage system for use as an uninterruptible power supply at a utility substation to replace electrochemical batteries has been modeled. The model is developed using the Electro-Magnetic Transients Program (EMTP). Models for the flywheel, permanent magnet (synchronous) motor/generator, rectifiers and inverter have been included. Transient response for loss of power and clearing of a short circuit fault, as well as variation of load voltage due to the flywheel spinning down, is presented.
Tao Yuan; Saleem Z. Ramadan; Suk Joo Bae
2011-01-01
Accurate yield prediction to evaluate productivity, and to estimate production costs, is a critical issue in the highly competitive semiconductor industry. We propose yield models based on hierarchical Bayesian modeling of clustered spatial defects produced in integrated circuits (IC) manufacturing. We use spatial locations of the IC chips on the wafers as covariates, and develop four models based on Poisson
Circuit Implementation of FitzHugh-Nagumo Neuron Model Using Field Programmable Analog Arrays
Ayers, Joseph
Circuit Implementation of FitzHugh-Nagumo Neuron Model Using Field Programmable Analog Arrays Jun ybk@ece.neu.edu Abstract-- A simple neuron model, the FitzHugh-Nagumo (FHN) model, is implemented and implementation results demonstrate that FPAA is the viable candidate for the neuron hardware implementation
Fernandez, Thomas
circuit optimization if one uses numerical performance modeling on simulation data to relate design of modeling approaches in the context of a reference optimization flow. Section II describes the flow. Section OPTIMIZATION FLOW There are many possible ways to use models to improve optimization efficiency. We limit
Makowiecki, Kalina; Harvey, Alan R.; Sherrard, Rachel M.
2014-01-01
Repetitive transcranial magnetic stimulation (rTMS) is increasingly used as a treatment for neurological and psychiatric disorders. Although the induced field is focused on a target region during rTMS, adjacent areas also receive stimulation at a lower intensity and the contribution of this perifocal stimulation to network-wide effects is poorly defined. Here, we examined low-intensity rTMS (LI-rTMS)-induced changes on a model neural network using the visual systems of normal (C57Bl/6J wild-type, n = 22) and ephrin-A2A5?/? (n = 22) mice, the latter possessing visuotopic anomalies. Mice were treated with LI-rTMS or sham (handling control) daily for 14 d, then fluorojade and fluororuby were injected into visual cortex. The distribution of dorsal LGN (dLGN) neurons and corticotectal terminal zones (TZs) was mapped and disorder defined by comparing their actual location with that predicted by injection sites. In the afferent geniculocortical projection, LI-rTMS decreased the abnormally high dispersion of retrogradely labeled neurons in the dLGN of ephrin-A2A5?/? mice, indicating geniculocortical map refinement. In the corticotectal efferents, LI-rTMS improved topography of the most abnormal TZs in ephrin-A2A5?/? mice without altering topographically normal TZs. To investigate a possible molecular mechanism for LI-rTMS-induced structural plasticity, we measured brain derived neurotrophic factor (BDNF) in the visual cortex and superior colliculus after single and multiple stimulations. BDNF was upregulated after a single stimulation for all groups, but only sustained in the superior colliculus of ephrin-A2A5?/? mice. Our results show that LI-rTMS upregulates BDNF, promoting a plastic environment conducive to beneficial reorganization of abnormal cortical circuits, information that has important implications for clinical rTMS. PMID:25100609
R. Sauleau; Ph. Coquet; J.-P. Daniel
2002-01-01
Accuracy of equivalent circuit models of periodic grids is investigated in amplitude and phase in the visible region. The grids studied here are one-dimensional (1D) and two-dimensional (2D) inductive thin metal meshes. They are located in free space and are illuminated by a plane wave under normal incidence. The range of validity and the accuracy of conventional circuit models are
Motor circuits are required to encode a sensory model for imitative learning
Roberts, Todd F.; Gobes, Sharon M.H.; Murugan, Malavika; Ölveczky, Bence P.; Mooney, Richard
2012-01-01
Summary Premotor circuits help generate complex behaviors, including those learned by imitation. Premotor circuits also can be activated during observation of another animal’s behavior, leading to speculation that they also participate in sensory learning important to imitation. Here we tested this idea by focally manipulating the brain activity of juvenile zebra finches, which learn to sing by memorizing and vocally copying the song of an adult tutor. Tutor song-contingent optogenetic or electrical disruption of neural activity in the pupil’s song premotor nucleus HVC prevented song copying, indicating that a premotor structure important to the temporal control of birdsong also helps encode the tutor song. In vivo multiphoton imaging and neural manipulations delineated a pathway and candidate synaptic mechanism through which tutor song information is encoded by premotor circuits. These findings provide evidence that premotor circuits help to encode sensory information about the behavioral model prior to shaping and executing imitative behaviors. PMID:22983208
Hu, Chia-Ren; HUANG, CH.
1991-01-01
PHYSICAL REVIEW B VOLUME 43, NUMBER 10 1 APRIL 1991 Phase boundary of a cubic superconducting circuit in a magnetic field of arbitrary magnitude and direction Chia-Ren Hu and Chen-Hong Huang Center for Theoretical Physics, Department of.... 1. The coordinate system used and the definition of [ 6;,i = 1 ?8 I relative to the coordinate system. 7720 CHIA-REN HU AND CHEN-HONG HUANG with ci =bi b?z/3, co=2bi/27 ?bib2/3+bc, and b2 = ?a2, b, =a,a, ?4ao, bo = ?(a, +aoa, ?4aoa, ).2 2...
Forward modelling of oceanic lithospheric magnetization
NASA Astrophysics Data System (ADS)
Masterton, S. M.; Gubbins, D.; Müller, R. D.; Singh, K. H.
2013-03-01
We construct a model of remanence for the oceans, combine it with a model of induced magnetization for the whole Earth from a previous study, compute the predicted lithospheric geomagnetic field and compare the result with a model, MF7, that is based on satellite data. Remanence is computed by assigning magnetizations to the oceanic lithosphere acquired at the location and time of formation. The magnetizing field is assumed to be an axial dipole that switches polarity with the reversal time scale. The magnetization evolves with time by decay of thermal remanence and acquisition of chemical remanence. The direction of remanence is calculated by Euler rotation of the original geomagnetic field direction with respect to an absolute reference frame, significantly improving previous results which did not include realistic oceanic magnetization computed this way. Remanence only accounts for 24 per cent of the energy of the oceanic magnetization, the induced magnetization being dominant, increasing slightly to 30 per cent of the part of the magnetization responsible for generating geomagnetic anomalies and 39 per cent of the Lowes energy of the geomagnetic anomalies. This is because our model of oceanic crust and lithosphere is fairly uniform, and a uniform layer magnetized by a magnetic field of internal origin produces no external field. The largest anomalies are produced by oceanic lithosphere magnetized during the Cretaceous Normal Superchron. Away from ridges and magnetic quiet zones the prediction fails to match the MF7 values; these are also generally, but not always, somewhat smaller than the observations. This may indicate that the magnetization estimates are too small, in which case the most likely error is in the poorly-known magnetization deep in the crust or upper mantle, or it may indicate some other source such as locally underplated continental lithosphere or anomalous oceanic crust, or even small-scale core fields.
Thermal modeling of the Tevatron magnet system
Jay C. Theilacker; Arkadiy L. Klebaner
2004-07-20
Operation of the Tevatron at lower temperatures, for the purpose of allowing higher energies, has resulted in a renewed interest in thermal modeling of the magnet strings. Static heat load and AC loses in the superconducting coils are initially transported through subcooled liquid helium. Heat exchange between the subcooled liquid and a counter flowing two-phase stream transfers the load to the latent heat. Stratification of the two-phase helium stream has resulted in considerably less heat exchange compared to the original design. Spool pieces have virtually no heat transfer to the two-phase resulting in a ''warm'' dipole just downstream. A model of the magnet string thermal behavior has been developed. The model has been used to identify temperature profiles within magnet strings. The temperature profiles are being used in conjunction with initial magnet quench performance data to predict the location of quench limiting magnets within the Tevatron. During thermal cycles of magnet strings, the model is being used to ''shuffle'' magnets within the magnet string in order to better match the magnets quench performance with its actual predicted temperature. The motivation for this analysis is to raise the operating energy of the Tevatron using a minimal number of magnets from the spares pool.
A digital neurmorphic circuit for a simplified model of astrocyte dynamics.
Nazari, Soheila; Faez, Karim; Karami, Ehsan; Amiri, Mahmood
2014-10-17
Recent neurophysiologic findings have shown that astrocytes (the most abundant type of glial cells) are active partners in neural information processing and regulate the synaptic transmission dynamically. Motivated by these findings, in the present research, a digital neuromorphic circuit to implement the astrocyte dynamics is developed. To model the dynamics of the intracellular Ca(2+) waves produced by astrocytes, we utilize a simplified model which considers the main physiological pathways of neuron-astrocyte interactions. Next, a digital circuit for the astrocyte dynamic is proposed which is simulated using ModelSim and finally, it is implemented in hardware on the ZedBoard. The results of hardware synthesis, FPGA implementations are in agreement with MATLAB and ModelSim simulations and confirm that the proposed digital astrocyte is suitable for applications in reconfigurable neuromorphic devices which implement biologically brain circuits. PMID:25108256
Equivalent-Circuit Model for the TSM Resonator with a Viscoelastic Layer
BANDEY, HELEN L.; CERNOSEK, RICHARD W.; HILLMAN, A.R.; MARTIN, STEPHEN J.
1999-09-16
This paper describes a new equivalent-circuit model for the thickness shear mode resonator with a surface viscoelastic layer operating near film resonance. The electrical impedance of the film is represented by a simple three-element parallel circuit containing a resistor, a capacitor, and an inductor. These elements describe the film's viscous power dissipation, elastic energy storage, and kinetic energy storage, respectively. Resonator response comparisons between this lumped-element model and the general transmission-line model show good agreement over a range of film phase conditions and not just near film resonance.
Simulink Modeling for Circuit Representation of Granular Chains
NASA Astrophysics Data System (ADS)
Sellami, Louiza; Newcomb, Robert W.; Sen, Surajit
2013-05-01
After a review of the coupled Newton's equations for a small alignment of grains with a fixed reflecting end wall, the equations are put into block diagrams of Simulink. Simulink simulations are given for 6 grain systems for cubic and Hertz intergrain potentials. The expected granular solitary waves are seen in the simulations. The block diagrams hence convert a single impulse into a traveling energy bundle of fixed width. This work forms the necessary first step for the eventual realization of the mathematical system represented by the granular chain as a Very Large Scale Integrated (VLSI) circuit.
Validation of an Accurate Three-Dimensional Helical Slow-Wave Circuit Model
NASA Technical Reports Server (NTRS)
Kory, Carol L.
1997-01-01
The helical slow-wave circuit embodies a helical coil of rectangular tape supported in a metal barrel by dielectric support rods. Although the helix slow-wave circuit remains the mainstay of the traveling-wave tube (TWT) industry because of its exceptionally wide bandwidth, a full helical circuit, without significant dimensional approximations, has not been successfully modeled until now. Numerous attempts have been made to analyze the helical slow-wave circuit so that the performance could be accurately predicted without actually building it, but because of its complex geometry, many geometrical approximations became necessary rendering the previous models inaccurate. In the course of this research it has been demonstrated that using the simulation code, MAFIA, the helical structure can be modeled with actual tape width and thickness, dielectric support rod geometry and materials. To demonstrate the accuracy of the MAFIA model, the cold-test parameters including dispersion, on-axis interaction impedance and attenuation have been calculated for several helical TWT slow-wave circuits with a variety of support rod geometries including rectangular and T-shaped rods, as well as various support rod materials including isotropic, anisotropic and partially metal coated dielectrics. Compared with experimentally measured results, the agreement is excellent. With the accuracy of the MAFIA helical model validated, the code was used to investigate several conventional geometric approximations in an attempt to obtain the most computationally efficient model. Several simplifications were made to a standard model including replacing the helical tape with filaments, and replacing rectangular support rods with shapes conforming to the cylindrical coordinate system with effective permittivity. The approximate models are compared with the standard model in terms of cold-test characteristics and computational time. The model was also used to determine the sensitivity of various circuit parameters including typical manufacturing dimensional tolerances and support rod permittivity. By varying the circuit parameters of an accurate model using MAFIA, these sensitivities can be computed for manufacturing concerns, and design optimization previous to fabrication, thus eliminating the need for costly experimental iterations. Several variations were made to a standard helical circuit using MAFIA to investigate the effect that variations on helical tape and support rod width, metallized loading height and support rod permittivity, have on TWT cold-test characteristics.
Qiu, S. S.; Zhuang, G.; Zhang, M.; Xia, D. H.; Rao, B.; Zhang, X. Q.; Pan, Y. [College of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China); Gentle, K. [Institute of Fusion Studies, University of Texas at Austin, Austin, Texas 78712 (United States)
2010-10-15
Four sets of magnetic diagnostic coils, which are printed on machinable ceramic printed circuit boards (PCB), are designed, fabricated, installed, and tested in the Joint Texas Experimental Tokamak (J-TEXT) vacuum vessel for detecting the plasma radial and vertical displacements relative to the geometric center of the vacuum vessel in Ohmic discharges. Each coordinate is determined by a pair of variable cross-section Rogowski and saddle coils, which measure the tangential and normal magnetic fields (relative to the coil surface). These coils are suitable for mass production and offer advantages in vacuum compatibility and temperature tolerance that are important for J-TEXT. Position measurements using PCB coils are compared with those from soft x-ray image system and match the position well.
A Visualization Tool for CFD Models of Convectively Cooled Printed Circuit Boards
Recktenwald, Gerald
A Visualization Tool for CFD Models of Convectively Cooled Printed Circuit Boards Gerald W.). The visualization tool serves as a post-processor to control-volume finite-difference CFD codes used to simulate in the fluid above the board. The PCBCAT are based on a novel computational fluid dynamics (CFD) model
Development of a Lumped Element Circuit Model for Approximation of Nanosecond Pulsed Dielectric
Roy, Subrata
to a computational fluid dynamics solver as an energy source term resulting in a coupled fluid/plasma dynamics model Barrier Discharges Thomas C. Underwood and Subrata Roy Computational Plasma Dynamics Laboratory and TestDevelopment of a Lumped Element Circuit Model for Approximation of Nanosecond Pulsed Dielectric
V.DMOS transistor modeling for simulation of power electronic circuits
Malgorzata Napieralska
1991-01-01
A nonlinear, short channel model of a power V.DMOS transistor, the elements of which depend only on physical and technological data, is presented. By an analysis of the active regions of the V.DMOS structure, in order to study switching modes, this model is simplified to a topology compatible with the SPICE circuit simulator. Parameter extraction methods and validation programs are
A physical large signal Si MOSFET model for RF circuit design
M. C. Ho; K. Green; R. Culbertson; J. Y. Yang; D. Ladwig; P. Ehnis
1997-01-01
A new physically based Si MOSFET large signal model, BSIM3v3, developed by UC Berkeley, has been evaluated for high-frequency mixed-signal circuit analysis in a frequency domain, harmonic balance simulator. The model is validated using simulated RF power characteristics of automatic load pull measurement at different bias and matching conditions
A General Approach to Sampled-Data Modeling for Power Electronic Circuits
George C. Verghese; Malik E. Elbuluk; John G. Kassakian
1986-01-01
A general sampled-data representation of the dynamics of arbitrary power electronic circuits is proposed to unify existing approaches. It leads, via compact and powerful notation, to disciplined modeling and straightforward derivation of small-signal models that describe perturbations about a nominal cyclic steady state. Its usefulness is further illustrated by considering the representation and analysis of a class of symmetries in
NEURAL MODELS FOR SOCIAL DEVELOPMENT IN SHARED PARIETO-MOTOR CIRCUITS
Pitti, Alexandre
.ac.jp 2 E-mail address: kuniyosh@isi.imi.i.u-tokyo.ac.jp #12;Neural Models for Shared Parieto-MotorChapter 1 NEURAL MODELS FOR SOCIAL DEVELOPMENT IN SHARED PARIETO-MOTOR CIRCUITS Alexandre Pitti1 Intelligence Project, Japan. ISI laboratory, University of Tokyo, Japan. 1 E-mail address: alex@isi.imi.i.u-tokyo
Goksen G. Yaralioglu; Mohammed H. Badi; A. Sanli Ergun; Butrus T. Khuri-Yakub
2003-01-01
Equivalent circuit model has been widely used to predict the bandwidth of capacitive micromachined ultrasonic transducers (CMUTs). According to this model, the lower cutoff of the bandwidth is determined by the time constant of the parallel RC where R is dictated by the radiation and C is determined by the electrical capacitance of the transducer. The higher cutoff, on the
Modeling and characterization of organic thin film transistors for circuit design
M. Fadlallah; W. Benzarti; G. Billiot; W. Eccleston; D. Barclay
2006-01-01
In this paper, we develop a device model of an organic thin film transistor for a circuit design, more specifically, for organic radio frequency identification applications. This model is based on variable range hopping theory, i.e., a carrier may either hop over a small distance with a high activation energy or hop over a long distance with a low activation
Model-free estimation of defect clustering in integrated circuit fabrication
David J. Friedman; Mark H. Hansen; Vijayan N. Nair; David A. James
1997-01-01
This paper describes a model-free method for estimating some yield metrics that are used to track integrated circuit fabrication processes. Our method uses binary probe test data at the wafer level to estimate the size, shape and location of large-area defects or clusters of defective chips. Unlike previous methods in the yield modeling literature, our approach makes extensive use of
Technische Universiteit Delft
in Bipolar Circuit Design V. Milovanovi´c* and S. Mijalkovi´c** *Delft Institute for Micro A reduction technique for an accurate modeling of complex effects manifested in an avalanche regime of bipolar is practically implemented on the bases of a vertical bipolar compact model Mextram. Extraction of an additional
Computer model for air-cooled refrigerant condensers with specified refrigerant circuiting
Ellison, R.D.; Creswick, F.A.; Fischer, S.K.; Jackson, W.L.
1981-01-01
A computer model for an air-cooled refrigerant condensor is presented; the model is intended for use in detailed design analyses or in simulation of the performance of existing heat exchangers that have complex refrigerant circuiting or unusual air-side geometries. The model relies on a tube-by-tube computational approach calculating the thermal and fluid-flow performance of each tube in the heat exchanger individually, using local temperatures and heat transfer coefficients. The refrigerant circuiting must be specified; the joining or branching of parallel circuits is accommodated using appropriate mixing expressions. Air-side heat exchange correlations may be specified so that various surface geometries can be investigated. Results of the analyses of two condensers are compared to experiment.
Lin, Li-Hsieh; Lee, Hsiao-Ching; Li, Wen-Hsiung; Chen, Bor-Sen
2005-01-01
Background Gene expression programs depend on recognition of cis elements in promoter region of target genes by transcription factors (TFs), but how TFs regulate gene expression via recognition of cis elements is still not clear. To study this issue, we define the cis-regulatory circuit of a gene as a system that consists of its cis elements and the interactions among their recognizing TFs and develop a dynamic model to study the functional architecture and dynamics of the circuit. This is in contrast to traditional approaches where a cis-regulatory circuit is constructed by a mutagenesis or motif-deletion scheme. We estimate the regulatory functions of cis-regulatory circuits using microarray data. Results A novel cross-gene identification scheme is proposed to infer how multiple TFs coordinate to regulate gene transcription in the yeast cell cycle and to uncover hidden regulatory functions of a cis-regulatory circuit. Some advantages of this approach over most current methods are that it is based on data obtained from intact cis-regulatory circuits and that a dynamic model can quantitatively characterize the regulatory function of each TF and the interactions among the TFs. Our method may also be applicable to other genes if their expression profiles have been examined for a sufficiently long time. Conclusion In this study, we have developed a dynamic model to reconstruct cis-regulatory circuits and a cross-gene identification scheme to estimate the regulatory functions of the TFs that control the regulation of the genes under study. We have applied this method to cell cycle genes because the available expression profiles for these genes are long enough. Our method not only can quantify the regulatory strengths and synergy of the TFs but also can predict the expression profile of any gene having a subset of the cis elements studied. PMID:16232312
Myers, Chris J.
Symbolic Model Checking of Analog/Mixed-Signal Circuits David Walter, Scott Little, Nicholas@nii.ac.jp Abstract-- This paper presents a Boolean based symbolic model checking algorithm for the verification of analog/mixed- signal (AMS) circuits. The systems are modeled in VHDL-AMS, a hardware description language
Microelectronic Devices and Circuits
NSDL National Science Digital Library
del Alamo, Jesus
The topics of this course include: modeling of microelectronic devices, basic microelectronic circuit analysis and design, physical electronics of semiconductor junction and MOS devices, relation of electrical behavior to internal physical processes, development of circuit models, and understanding the uses and limitations of various models. The course uses incremental and large-signal techniques to analyze and design bipolar and field effect transistor circuits, with examples chosen from digital circuits, single-ended and differential linear amplifiers, and other integrated circuits.
A GLOBAL MAGNETIC TOPOLOGY MODEL FOR MAGNETIC CLOUDS. II
Hidalgo, M. A., E-mail: miguel.hidalgo@uah.es [Departamento de Fisica, Universidad de Alcala, Apartado 20, E-28871 Alcala de Henares, Madrid (Spain)
2013-04-01
In the present work, we extensively used our analytical approach to the global magnetic field topology of magnetic clouds (MCs), introduced in a previous paper, in order to show its potential and to study its physical consistency. The model assumes toroidal topology with a non-uniform (variable maximum radius) cross-section along them. Moreover, it has a non-force-free character and also includes the expansion of its cross-section. As is shown, the model allows us, first, to analyze MC magnetic structures-determining their physical parameters-with a variety of magnetic field shapes, and second, to reconstruct their relative orientation in the interplanetary medium from the observations obtained by several spacecraft. Therefore, multipoint spacecraft observations give the opportunity to infer the structure of this large-scale magnetic flux rope structure in the solar wind. For these tasks, we use data from Helios (A and B), STEREO (A and B), and Advanced Composition Explorer. We show that the proposed analytical model can explain quite well the topology of several MCs in the interplanetary medium and is a good starting point for understanding the physical mechanisms under these phenomena.
Using Simple Circuits as Thermal Models for Your Home
NASA Astrophysics Data System (ADS)
Poynor, Adele
2014-02-01
In 2009, President Obama proposed an initiative to decrease our country's energy consumption and dependence on fossil fuels. One key to this plan was to decrease the amount of energy used to heat and cool our homes through government incentives. The EPA estimates that the average American household spends over 1000 annually for heating and cooling. One of the most cost-effective ways of decreasing energy use in your home is to stop air penetration and increase the amount of insulation by installing insulated doors, insulated windows, and cavity wall insulation. But not all options are equally effective, nor do they have equal costs. So how can consumers determine which option improves their homes' insulation the most? In this paper, I present an analogy to simple resistor circuits that can be used by introductory students to answer this question.
A GLOBAL MAGNETIC TOPOLOGY MODEL FOR MAGNETIC CLOUDS. I
Hidalgo, M. A. [Departamento de Fisica, Universidad de Alcala (Spain); Nieves-Chinchilla, T., E-mail: miguel.hidalgo@uah.es, E-mail: teresa.nieves-chinchil-1@nasa.gov [Institute for Astrophysics and Computational Sciences Catholic University of America, Washington, DC (United States)
2012-04-01
We present an analytical approach to the global magnetic field topology of magnetic clouds (MCs) that considers them like close magnetic structures with torus geometry and with a non-uniform (variable maximum radius) cross section along them. Following our previous approach to the problem of MCs (Hidalgo 2003, 2011), we establish an intrinsic coordinate system for that topology, and then we analytically solve the Maxwell equations in terms of it. The purpose of the present work is to present this model, which will lead us to understand in a more realistic way the physical mechanisms inside MCs. The model has a non-force-free character and also takes into account the time evolution of the cross sections of the MCs in their movement through the interplanetary medium. In this first paper, we obtain the expressions for the components of the magnetic field and the plasma current density imposing a large mean radius of the torus, and imposing a circular cross section with a variable maximum radius. Eventually, we fit the model to data related to four well-known MCs measurements at 1 AU, (three of them with circular cross sections and without expansion, as it is deduced from the experimental data). We compare the results of this toroidal model with those obtained with our previous cylindrical circular cross section model, also with a non-force-free character.
A Global Magnetic Topology Model for Magnetic Clouds. I.
NASA Astrophysics Data System (ADS)
Hidalgo, M. A.; Nieves-Chinchilla, T.
2012-04-01
We present an analytical approach to the global magnetic field topology of magnetic clouds (MCs) that considers them like close magnetic structures with torus geometry and with a non-uniform (variable maximum radius) cross section along them. Following our previous approach to the problem of MCs (Hidalgo 2003, 2011), we establish an intrinsic coordinate system for that topology, and then we analytically solve the Maxwell equations in terms of it. The purpose of the present work is to present this model, which will lead us to understand in a more realistic way the physical mechanisms inside MCs. The model has a non-force-free character and also takes into account the time evolution of the cross sections of the MCs in their movement through the interplanetary medium. In this first paper, we obtain the expressions for the components of the magnetic field and the plasma current density imposing a large mean radius of the torus, and imposing a circular cross section with a variable maximum radius. Eventually, we fit the model to data related to four well-known MCs measurements at 1 AU, (three of them with circular cross sections and without expansion, as it is deduced from the experimental data). We compare the results of this toroidal model with those obtained with our previous cylindrical circular cross section model, also with a non-force-free character.
Equivalent circuit of radio frequency-plasma with the transformer model.
Nishida, K; Mochizuki, S; Ohta, M; Yasumoto, M; Lettry, J; Mattei, S; Hatayama, A
2014-02-01
LINAC4 H(-) source is radio frequency (RF) driven type source. In the RF system, it is required to match the load impedance, which includes H(-) source, to that of final amplifier. We model RF plasma inside the H(-) source as circuit elements using transformer model so that characteristics of the load impedance become calculable. It has been shown that the modeling based on the transformer model works well to predict the resistance and inductance of the plasma. PMID:24593557
A Yield Model for Integrated Circuits and its Application to Statistical Timing Analysis
Farid N. Najm; Noel Menezes; Imad A. Ferzli
2007-01-01
A model for process-induced parameter variations is proposed, combining die-to-die, within-die systematic, and within- die random variations. This model is put to use toward finding suitable timing margins and device file settings, to verify whether a circuit meets a desired timing yield. While this parameter model is cognizant of within-die correlations, it does not require specific variation models, layout information,
Realistic single-electron transistor modeling and novel CMOS\\/SET hybrid circuits
Ki-Whan Song; Gwanghyeon Baek; Sang-Hoon Lee; Dae Hwan Kim; Kyung Rok Kim; Dong-Soo Woo; Jae Sung Sim; Jong Duk Lee; Byung-Gook Park
2003-01-01
A practical single electron transistor (SET) model has been proposed with appropriate modifications to the previous analytical model. We have observed that non-ideal SET current behaviors such as turn-off and peak-to-valley ratio (PVCR) degradation is successfully reproduced by the new SET model. Based on the realistic SET model, we have developed a novel circuit scheme which enhances the stability of
Modeling spin magnetization transport in a spatially varying magnetic field
NASA Astrophysics Data System (ADS)
Picone, Rico A. R.; Garbini, Joseph L.; Sidles, John A.
2015-01-01
We present a framework for modeling the transport of any number of globally conserved quantities in any spatial configuration and apply it to obtain a model of magnetization transport for spin-systems that is valid in new regimes (including high-polarization). The framework allows an entropy function to define a model that explicitly respects the laws of thermodynamics. Three facets of the model are explored. First, it is expressed as nonlinear partial differential equations that are valid for the new regime of high dipole-energy and polarization. Second, the nonlinear model is explored in the limit of low dipole-energy (semi-linear), from which is derived a physical parameter characterizing separative magnetization transport (SMT). It is shown that the necessary and sufficient condition for SMT to occur is that the parameter is spatially inhomogeneous. Third, the high spin-temperature (linear) limit is shown to be equivalent to the model of nuclear spin transport of Genack and Redfield (1975) [1]. Differences among the three forms of the model are illustrated by numerical solution with parameters corresponding to a magnetic resonance force microscopy (MRFM) experiment (Degen et al., 2009 [2]; Kuehn et al., 2008 [3]; Sidles et al., 2003 [4]; Dougherty et al., 2000 [5]). A family of analytic, steady-state solutions to the nonlinear equation is derived and shown to be the spin-temperature analog of the Langevin paramagnetic equation and Curie's law. Finally, we analyze the separative quality of magnetization transport, and a steady-state solution for the magnetization is shown to be compatible with Fenske's separative mass transport equation (Fenske, 1932 [6]).
Transmission line circuit model of a PPy based trilayer mechanical sensor
NASA Astrophysics Data System (ADS)
Khalili, Nazanin; Naguib, Hani E.; Kwon, Roy H.
2015-04-01
Many efforts have been devoted to modeling the diffusive impedance of conjugated polymer (CP) based actuators using their equivalent electrical circuits. Employing the same methodology, CP based mechanical sensors can also be treated by an equivalent transmission line circuit and their overall impedance can be modeled, correspondingly. Due to the large number of resources to study the electrical circuits, this technique is a practical tool. Therefore, in this study, an equivalent RC-circuit model including electrochemical parameters is determined to obtain a better perception of the sensing mechanism of these mechanical sensors. Conjugated polymers are capable of generating an output current or voltage upon an induced mechanical deformation or force. This observed behavior in polymer based mechanical sensors is considered as the reverse actuation process. Many outstanding properties of the conjugated polymer actuators including their light weight and biocompatibility are still retained by these sensors. Sensors with a trilayer configuration are capable of operating in air in response to a mechanically induced bending deformation. However, due to their nonlinear behavior and multivariable characteristics, it is required to propose a systematic approach in order to optimize their performance and gain the optimal values of their constituent decision variable. Therefore, the proposed mathematical model is used to define the output voltage of the PPy based mechanical sensor along with the sensitivity of the model to the applied frequency of the induced deformation. Applying a multiobjective optimization algorithm, the optimization problem was solved and the tracking ability of the proposed model was then verified.
NASA Astrophysics Data System (ADS)
Tong, Shijie
Energy storage is one of society's grand challenges for the 21st century. Lithium ion batteries (LIBs) are widely used in mobile devices, transportation, and stationary energy storages due to lowering cost combined with excellent power/energy density as well as cycle durability. The need for a battery management system (BMS) arises from a demand to improve cycle life, assure safety, and optimize the full pack performance. In this work, we proposed a model based battery on-line state of charge (SoC) and state of health (SoH) estimator for LIBs. The estimator incorporates a comprehensive Equivalent Circuit Model (ECM) as reference, an Extended Kalman Filter (EKF) as state observer, a Recursive Least Square (RLS) algorithm as parameter identifier, and Parameter Varying Approach (PVA) based optimization algorithms for the parameter function regressions. The developed adaptive estimator was applied to a 10kW smart grid energy storage application using retired electric vehicle batteries. The estimator exhibits a high numerical efficiency as well as an excellent accuracy in estimating SoC and SoH. The estimator also provides a novel method to optimize the correlation between battery open circuit voltage (OCV) and SoC, which further improves states estimation accuracy.
MODELING COERCIVITY OF SOFT MAGNETIC MATERIALS
E. Della Torre
1988-01-01
Both physical and phenomenological models are necessary to obtain good descriptions of coercivity in soft magnetic materials. The former models give insight into the processes involved, while the latter models compute quickly. The differences between modeling soft and hard materials are the parameters sizes and the importance of eddy currents.
Ensemble Solar Global Magnetic Field Modeling
C. J. Henney; C. N. Arge; J. Koller; W. A. Toussaint; S. L. Young; J. W. Harvey
2010-01-01
The ability to forecast geoeffective space weather events is critically dependent on the estimation of the global solar photospheric magnetic field distribution as input to coronal and heliospheric models. Currently, the solar magnetic field can only be recorded for approximately half of the solar surface at any given time. Since the rotation period of the Sun as observed from Earth
Geospace Environmental Modeling (GEM) magnetic reconnection challenge
J. Birn; J. F. Drake; M. A. Shay; B. N. Rogers; R. E. Denton; M. Hesse; M. Kuznetsova; Z. W. Ma; A. Bhattacharjee; A. Otto; P. L. Pritchett
2001-01-01
The Geospace Environmental Modeling (GEM) Reconnection Challenge project is presented and the important results, which are presented in a series of companion papers, are summarized. Magnetic reconnection is studied in a simple Harris sheet configuration with a specified set of initial conditions, including a finite amplitude, magnetic island perturbation to trigger the dynamics. The evolution of the system is explored
A physics-based MTO model for circuit simulation
Y. Bai; A. Q. Huang
2000-01-01
This paper presents a comprehensive model of the MTO (MOS turn-off thyristor) based on the lumped-charge modeling technique. The model includes important effects such as avalanche breakdown, Auger recombination and conductivity modulation. The thermal effect is also included in this model. The model is implemented as a MAST template in the Saber simulator and is compared with numerical simulation
Modeling and analysis of power extraction circuits for passive UHF RFID applications
NASA Astrophysics Data System (ADS)
Bo, Fan; Yujie, Dai; Xiaoxing, Zhang; Yingjie, Lü
2009-01-01
Modeling and analysis of far field power extraction circuits for passive UHF RF identification (RFID) applications are presented. A mathematical model is derived to predict the complex nonlinear performance of UHF voltage multiplier using Schottky diodes. To reduce the complexity of the proposed model, a simple linear approximation for Schottky diode is introduced. Measurement results show considerable agreement with the values calculated by the proposed model. With the derived model, optimization on stage number for voltage multiplier to achieve maximum power conversion efficiency is discussed. Furthermore, according to the Bode-Fano criterion and the proposed model, a limitation on maximum power up range for passive UHF RFID power extraction circuits is also studied.
Threshold flux-controlled memristor model and its equivalent circuit implementation
NASA Astrophysics Data System (ADS)
Wu, Hua-Gan; Bao, Bo-Cheng; Chen, Mo
2014-11-01
Modeling a memristor is an effective way to explore the memristor properties due to the fact that the memristor devices are still not commercially available for common researchers. In this paper, a physical memristive device is assumed to exist whose ionic drift direction is perpendicular to the direction of the applied voltage, upon which, corresponding to the HP charge-controlled memristor model, a novel threshold flux-controlled memristor model with a window function is proposed. The fingerprints of the proposed model are analyzed. Especially, a practical equivalent circuit of the proposed model is realized, from which the corresponding experimental fingerprints are captured. The equivalent circuit of the threshold memristor model is appropriate for various memristors based breadboard experiments.
Toni López; Reinhold Elferich; Nick Koper; E. Alarcon
2006-01-01
Circuit simulator diode lumped models are investigated for representing the reverse recovery of low voltage power trench MOSFETs. Three previously presented models are compared in terms of internal constitution, circuit implementation, prediction accuracy and required computation power. 2D finite element simulations of a trench MOSFET cell underlie the prediction accuracy study. The purpose of this work is to obtain an
Modeling and optimization of permanent magnetic motors
Pinkham, Andrew P
2008-01-01
This thesis develops analytic models for the prediction and optimization of radial-flux permanent magnet motor torque and efficiency. It also facilitates the design optimization of electromagnetically-powered rotorcraft ...
G. B. Burns; B. A. Tinsley; A. V. Frank-Kamenetsky; E. A. Bering
2007-01-01
The Mansurov effect, which for the Southern Hemisphere consists of a positive association between the By component (east-west) of the interplanetary magnetic field (IMF) and the ground-level pressure for stations poleward of ?80° magnetic latitude, is confirmed for Vostok (78.5°S, 106.9°E; magnetic latitude 83.6°S) using modern data. The magnitude of the association is small (0.19 hP per nT; 1.2% common
Magnetic field decay in model SSC dipoles
Gilbert, W.S.; Althaus, R.F.; Barale, P.J.; Benjegerdes, R.W.; Green, M.A.; Green, M.I.; Scanlan, R.M.
1988-08-01
We have observed that some of our model SSC dipoles have long time constant decays of the magnetic field harmonics with amplitudes large enough to result in significant beam loss, if they are not corrected. The magnets were run at constant current at the SSC injection field level of 0.3 tesla for one to three hours and changes in the magnetic field were observed. One explanation for the observed field decay is time dependent superconductor magnetization. Another explanation involves flux creep or flux flow. Data are presented on how the decay changes with previous flux history. Similar magnets with different Nb-Ti filament spacings and matrix materials have different long time field decay. A theoretical model using proximity coupling and flux creep for the observed field decay is discussed. 10 refs., 5 figs., 2 tabs.
Caveats in modeling a common motif in genetic circuits
NASA Astrophysics Data System (ADS)
Labavi?, Darka; Nagel, Hannes; Janke, Wolfhard; Meyer-Ortmanns, Hildegard
2013-06-01
From a coarse-grained perspective, the motif of a self-activating species, activating a second species that acts as its own repressor, is widely found in biological systems, in particular in genetic systems with inherent oscillatory behavior. Here we consider a specific realization of this motif as a genetic circuit, termed the bistable frustrated unit, in which genes are described as directly producing proteins. Upon an improved resolution in time, we focus on the effect that inherent time scales on the underlying scale can have on the bifurcation patterns on a coarser scale. Time scales are set by the binding and unbinding rates of the transcription factors to the promoter regions of the genes. Depending on the ratio of these rates to the decay times of both proteins, the appropriate averaging procedure for obtaining a coarse-grained description changes and leads to sets of deterministic equations, which considerably differ in their bifurcation structure. In particular, the desired intermediate range of regular limit cycles fades away when the binding rates of genes are not fast as compared to the decay time of the proteins. Our analysis illustrates that the common topology of the widely found motif alone does not imply universal features in the dynamics.
NASA Technical Reports Server (NTRS)
Courey, Karim; Wright, Clara; Asfour, Shihab; Onar, Arzu; Bayliss, Jon; Ludwig, Larry
2009-01-01
In this experiment, an empirical model to quantify the probability of occurrence of an electrical short circuit from tin whiskers as a function of voltage was developed. This empirical model can be used to improve existing risk simulation models. FIB and TEM images of a tin whisker confirm the rare polycrystalline structure on one of the three whiskers studied. FIB cross-section of the card guides verified that the tin finish was bright tin.
CAD-oriented equivalent-circuit modeling of on-chip interconnects on lossy silicon substrate
Ji Zheng; Yeon-Chang Hahm; Vijai K. Tripathi; Andreas Weisshaar
2000-01-01
A new, comprehensive CAD-oriented modeling methodology for single and coupled interconnects on an Si-SiO2 substrate is presented. The modeling technique uses a modified quasi-static spectral domain electromagnetic analysis which takes into account the skin effect in the semiconducting substrate. Equivalent-circuit models with only ideal lumped elements, representing the broadband characteristics of the interconnects, are extracted. The response of the proposed
Novel Circuit Models of Arbitrary-Shape Line: Application to Parallel Coupled Microstrip Filters
Paris-Sud XI, Université de
software to simulate and design many configurations of arbitrary-shape line. The global shape is controlled are mainly used as impedance-matching devices, pulse transformers, resonators, couplers and filters. Abstract -- Following a hierarchical approach, several models are built in microwave-circuit design
A Transregional Model for Near-Threshold Circuits with Application to Minimum-Energy Operation
Harris, David Money
such as implantable medical devices, wireless sensor networks, and RFID tags, researchers are increasingly interested model for Ion that is valid in the near-threshold region. Based on the ON-current, a propagation delay in operating CMOS circuits below or near the device threshold voltage (Vt) [1]. Furthermore, throughput
Thermal Modeling, Analysis and Management in VLSI Circuits: Principles and Methods
Pedram, Massoud
1 Thermal Modeling, Analysis and Management in VLSI Circuits: Principles and Methods Massoud Pedram have made thermal effects one of the most important concerns of VLSI designers. The increasing. Recent data shows that more than 50% of all IC failures are related to thermal issues. This article
Biological Circuit Models of Immune Regulatory Response: A Decentralized Control System
Peet, Matthew M.
Biological Circuit Models of Immune Regulatory Response: A Decentralized Control System Matthew control based on recently discovered regulatory properties of the immune system. The immune system. INTRODUCTION The purpose of this paper is to improve our understanding of the immune system by understanding
Analysis and modeling of bang-bang clock and data recovery circuits
Jri Lee; Kenneth S. Kundert; Behzad Razavi
2004-01-01
Abstract, A large-signal piecewise-linear model is proposed for bang-bang phase detectors that predicts characteristics of clock and data recovery circuits such as jitter transfer, jitter tolerance, and jitter generation. The results are validated by 1-Gb\\/s and 10-Gb\\/s CMOS prototypes using an Alexander phase detector and an LC oscillator.
Improved cement quality and grinding efficiency by means of closed mill circuit modeling
Mejeoumov, Gleb Gennadievich
2009-05-15
in the industrial mill are not available. Based on a population balance principle and stochastic representation of the particle movement within the grinding system, the Markov chain model for the circuit consisting of a tube ball mill and a high efficiency separator...
NASA Technical Reports Server (NTRS)
1976-01-01
Assumptions made and techniques used in modeling the power network to the 480 volt level are discussed. Basic computational techniques used in the short circuit program are described along with a flow diagram of the program and operational procedures. Procedures for incorporating network changes are included in this user's manual.
Circuit-oriented discrete-time modeling and simulation for switching converters
C. J. Hsiao; R. B. Ridley; H. Naitoh; F. C. Lee
1987-01-01
A generalized discrete-time modeling and simulation program, applicable to any PWM, resonant, or quasiresonant converter, has been developed. From a circuit description, this program automatically generates state-space equations corresponding to each switching interval and performs time-domain simulation by using state-transition equations with a fast-convergence algorithm for topological changes.
An accurate and efficient delay time modeling for MOS logic circuits using polynomial approximation
Young-hyun Jun; Ki Jun; Song-bai Park
1989-01-01
A delay model for multiple delay simulation for NMOS and CMOS logic circuits is proposed. For the simple inverter the rise or fall delay time is approximated by a product of polynomials of the input waveform slope, the output loading capacitance, and the device configuration ratio, with the polynomial coefficients determined so as to best fit the SPICE simulation results
Equivalent circuit model of traveling-wave maser slow-wave structures
NASA Technical Reports Server (NTRS)
Shell, J.
1991-01-01
An approach is presented for deriving transmission line equivalent circuits that can approximately model the S-parameter response of traveling wave maser slow wave structures. The technique is illustrated by computing the S-parameter responses of an X-band and S-band maser slow wave structure and comparing these with experimental measurements.
New models and heuristics for component placement in printed circuit board assembly
Edmund K. Burke; Peter I. Cowling; Ralf Keuthen
1999-01-01
The paper considers an optimization problem arising in the automated manufacture of printed circuit boards. An essential part of this problem is to determine good component pick and place sequences as this can reduce the overall assembly time significantly. This component placement sequence problem can be modelled as a Travelling Salesman Problem, however complex machine and process specifications also arise
Modeling and Reduction of Gate Leakage during Behavioral Synthesis of NanoCMOS Circuits
Mohanty, Saraju P.
: smohanty@cs.unt.edu Email: eliask@unt.edu Abstract-- For a nanoCMOS of sub-65nm technology, where the gate for low-end nanoCMOS technology (i. e. sub-65nm) using ultra-thin gate oxide [4], [2], [5]. ThusModeling and Reduction of Gate Leakage during Behavioral Synthesis of NanoCMOS Circuits Saraju P
Models for physics of failures analysis during printed circuit board bending
Jan-Long Yang; Mei-Ling Wu
2011-01-01
This paper summarizes the force calculation at each pitch position for the structure, where a component (overmold, die, and BT) is attached to a PCB (printed circuit board) through an array of solder joints with an external bending moment applied at the ends of PCB. In this paper, the results from the model proposed by E. Suhir [1] are summarized
Analysis of vertical multijunction solar cells using a distributed circuit model
P. Shah
1975-01-01
This work describes an analysis of some of the vertical multijunction (VMJ) cell structures now being fabricated - especially the ones that combine the enhanced red response and radiation tolerance of the VMJ concept and blue response of conventional planar cells. A distributed equivalent circuit model is used for analysis of complicated junction configurations - which otherwise would be very
Busby, Cathy
Magnetic field gradients from the ST-5 constellation: Improving magnetic and thermal models. The measurements reported here represent the first systematic measurements of lithospheric magnetic field gradients are dominated by lithospheric magnetic fields. Using a seismic starting model, and magnetic field observations
NeuroGPS: automated localization of neurons for brain circuits using L1 minimization model
NASA Astrophysics Data System (ADS)
Quan, Tingwei; Zheng, Ting; Yang, Zhongqing; Ding, Wenxiang; Li, Shiwei; Li, Jing; Zhou, Hang; Luo, Qingming; Gong, Hui; Zeng, Shaoqun
2013-04-01
Drawing the map of neuronal circuits at microscopic resolution is important to explain how brain works. Recent progresses in fluorescence labeling and imaging techniques have enabled measuring the whole brain of a rodent like a mouse at submicron-resolution. Considering the huge volume of such datasets, automatic tracing and reconstruct the neuronal connections from the image stacks is essential to form the large scale circuits. However, the first step among which, automated location the soma across different brain areas remains a challenge. Here, we addressed this problem by introducing L1 minimization model. We developed a fully automated system, NeuronGlobalPositionSystem (NeuroGPS) that is robust to the broad diversity of shape, size and density of the neurons in a mouse brain. This method allows locating the neurons across different brain areas without human intervention. We believe this method would facilitate the analysis of the neuronal circuits for brain function and disease studies.
Analytical thermal model for magnetic components
L. M. Escribano; R. Prieto; J. A. Oliver; J. A. Cobos; J. Uceda
2003-01-01
1D thermal models are often used in the design of magnetic components in order to obtain an optimum design for a specific application. These thermal resistor-based models usually consider a thermal network based on the analogy between electricity and heat transfer equations. These models consider heat transfer in axial or radial direction using different electric elements, and using this analogy,
Design and Commissioning of the Energy Extraction Systems for the LHC Corrector Magnet Circuits
G. J. Coelingh; K. Dahlerup-Petersen; A. Erokhin; K. Gorchakov; A. Medvedko
2008-01-01
CERN is currently commissioning the world's largest particle accelerator, the large hadron collider (LHC). The machine makes extensive use of superconducting technology for magnets, busbars and current leads. It is built in a circular tunnel of 27 km circumference, ready to receive proton beams in the summer of 2008. In case of a resistive transition (quench) in a superconducting magnet
Guillaume Crevecoeur; Luc Dupr; Rik Van de Walle
2007-01-01
Production processes like cutting, performed on electrical steel laminations, influence their magnetic properties locally. Since the magnetic design of electrical machines does not take this effect into account accurately, the design may be suboptimal. Therefore, the need exists to develop a numerical procedure which is capable of optimizing electrical devices, taking into account the local material degradation and featuring high
Olfactory Functions Scale with Circuit Restoration in a Rapidly Reversible Alzheimer's Disease Model
Cheng, Ning; Bai, Li; Steuer, Elizabeth
2013-01-01
Neural circuits maintain a precise organization that is vital for normal brain functions and behaviors, but become disrupted during neurological disease. Understanding the connection between wiring accuracy and function to measure disease progression or recovery has been difficult because of the complexity of behavioral circuits. The olfactory system maintains well-defined neural connections that regenerate throughout life. We previously established a reversible in vivo model of Alzheimer's disease by overexpressing a humanized mutated amyloid precursor protein (hAPP) in olfactory sensory neurons (OSNs). Using this model, we currently show that hAPP is present in the OSN axons of mutant mice, which exhibit strong caspase3 signal and reduced synaptic protein expression by 3 weeks of age. In the olfactory bulb, we show that glomerular structure is distorted and OSN axonal convergence is lost. In vivo functional imaging experiments further demonstrate disruption of the glomerular circuitry, and behavioral assays reveal that olfactory function is significantly impaired. Because OSNs regenerate, we also tested if the system could recover from hAPP-induced disruption. We found that after 1 or 3 weeks of shutting-off hAPP expression, the glomerular circuit was partially restored both anatomically and functionally, with behavioral deficits similarly reversed. Interestingly, the degree of functional recovery tracked directly with circuit restoration. Together, these data demonstrate that hAPP-induced circuit disruption and subsequent recovery can occur rapidly and that behavior can provide a measure of circuit organization. Thus, olfaction may serve as a useful biomarker to both follow disease progression and gauge potential recovery. PMID:23884929
Equivalent circuit modeling of hybrid electric vehicle drive train
Routex, Jean-Yves
2001-01-01
cell system. Figure 4. 5. 4: Electrical model of the battery system. Figure 4. 5. 5: Electrical model of the hybrid energy storage Figure 4. 5. 6: Electrical model of the flywheel system. . Figure 5. 1. 1: Electric vehicle architecture Figure 5. 1... of Power Plants and Energy Storage . . . 4. 6 Summary and Conclusion 5. MODELING AND DESIGN OF THE COMPLETE HEV DRIVE TRAIN. . . . 5. 1 Modeling and Design of the Different Architectures. 5. 2 Example of Design: the Series Hybrid Electric Drive Train...
Li, Dongling; Wen, Zhiyu; Wen, Zhongquan; He, Xuefeng; Yang, Yinchuan; Shang, Zhengguo
2009-01-01
A novel high-precision vacuum microelectronic accelerometer has been successfully fabricated and tested in our laboratory. This accelerometer has unique advantages of high sensitivity, fast response, and anti-radiation stability. It is a prototype intended for navigation applications and is required to feature micro-g resolution. This paper briefly describes the structure and working principle of our vacuum microelectronic accelerometer, and the mathematical model is also established. The performances of the accelerometer system are discussed after Matlab modeling. The results show that, the dynamic response of the accelerometer system is significantly improved by choosing appropriate parameters of signal detecting circuit, and the signal detecting circuit is designed. In order to attain good linearity and performance, the closed-loop control mode is adopted. Weak current detection technology is studied, and integral T-style feedback network is used in I/V conversion, which will eliminate high-frequency noise at the front of the circuit. According to the modeling parameters, the low-pass filter is designed. This circuit is simple, reliable, and has high precision. Experiments are done and the results show that the vacuum microelectronic accelerometer exhibits good linearity over -1 g to +1 g, an output sensitivity of 543 mV/g, and a nonlinearity of 0.94 %. PMID:22408515
Verilog-A modeling of SPAD for circuit simulations
NASA Astrophysics Data System (ADS)
Yang, Hong-jiao; Jin, Xiang-liang; Zhou, Xiao-ya; Chen, Chang-ping; Luo, Jun
2013-08-01
A behavior mode for simulating single-photon avalanche diodes is presented. The model is developed using Verilog-A description language. The derived model is able to describe the static, the dynamic behavior, the triggering, the self-sustaining and the self-quenching processes, and it also correctly characterizes the reverse current-voltage curve. Simulation results confirmed the validity of the proposed model.
Physics based lumped element circuit model for nanosecond pulsed dielectric barrier discharges
NASA Astrophysics Data System (ADS)
Underwood, Thomas; Roy, Subrata; Glaz, Bryan
2013-02-01
This work presents a physics based circuit model for calculating the total energy dissipated into neutral species for nanosecond pulsed direct current (DC) dielectric barrier discharge (DBD) plasmas. Based on experimental observations, it is assumed that the nanosecond pulsed DBD's which have been proposed for aerodynamic flow control can be approximated by two independent regions of homogeneous electric field. An equivalent circuit model is developed for both homogeneous regions based on a combination of a resistor, capacitors, and a zener diode. Instead of fitting the resistance to an experimental data set, a formula is established for approximating the resistance by modeling plasmas as a conductor with DC voltage applied to it. Various assumptions are then applied to the governing Boltzmann equation to approximate electrical conductivity values for weakly ionized plasmas. The developed model is then validated with experimental data of the total power dissipated by plasmas.
Simple SPICE model for comparison of CMOS output driver circuits
Hermann, John Karl
1993-01-01
INTRODUCTION . A. Literature Survey SPEED AND NOISE A. Speed 1. Rise and Fall Times 2. Propagation Delays B. Noise 1. Board Level Problems . 2. Chip Level Problems . 3. Speed vs Noise Trade-off THE SIMULATION MODEL A. Model Attributes B. Using... the Model. 4 5 7 8 10 12 12 14 14 17 IV PROVING THE MODEL A. 128X8 ROM . . B. Internal CMOS Sensing Amplifier C. Output Drivers 1. Output Driver pl 2. Output Driver P2 3. Output Pad Configuration D. Comparison Approach 1. Timing 2. Noise...
NASA Astrophysics Data System (ADS)
Ito, S.; Mifune, T.; Matsuo, T.; Suzuki, M.; Kawano, K.
2014-05-01
The finite element (FE) modeling of a ferrite-core device is discussed. Measured properties of Ni-Zn ferrite ring cores show that even though the AC ferrite property is similar to that caused by the eddy-current field, the FE eddy-current analysis using an equivalent electrical conductivity cannot, in practice, represent the AC property. An equivalent-circuit model which describes AC/DC ferrite properties is applied to FE magnetic field analysis of a ferrite-core inductor. The simulated AC property with/without DC bias agrees with the measured one.
Bond, Bradley N.
This paper presents a system identification technique for generating stable compact models of typical analog circuit blocks in radio frequency systems. The identification procedure is based on minimizing the model error ...
Behavioural model of Spin Torque Transfer Magnetic Tunnel Junction, Using Verilog-A
NASA Astrophysics Data System (ADS)
Garg, Rishubh; Kumar, Deepak; Jindal, Navneet; Negi, Nandita; Ahuja, Chetna
2012-11-01
A novel simple and efficient model of Spin Torque Transfer Magnetic Tunnel Junction (STT-MTJ) is presented. The model is implemented using Verilog-A. The model accurately emulates the main properties of an STT-MTJ which includes Tunnel Magneto resistance Ratio (TMR), its dependence on the voltage bias and the Critical switching current. The novelty of the model lies in the fact that the voltage dependence of TMR has been modeled using a single equation dividing it into three different operating regions. A register based on the model is also developed. The model can be used for faster simulations of hybrid Magnetic CMOS circuits and in various other wide range of applications. The models were verified using Synopsys Hspice 2010.
Using electronic circuits to model simple neuroelectric interactions
E. R. Lewis
1968-01-01
The Hodgkin-Huxley description of electrically excitable conductances is combined with the Eccles description of synaptic conductances to provide the basis of an electronic model of nerve-cell membrane. The models are used to explore neuroelectric interactions between spatially distributed regions of a single neuron and neuroelectric activities in very small groups of neurons. Among other things, oscillations are found to conduct
MOSFET modeling for analog circuit CAD: problems and prospects
Yannis P. Tsividis; Ken Suyama
1994-01-01
The requirements for good MOSFET modeling are discussed, as they apply to usage in analog and mixed analog-digital design. A set of benchmark tests that can be easily performed by the reader are given, and it is argued that most CAD models today cannot pass all the tests, even for simple, long-channel devices at room temperature. A number of other
Equivalent Circuit Model for Thick Split Ring Resonators and Thick Spiral Resonators
Mancera, Laura Maria Pulido
2014-01-01
A simple theoretical model which provides circuit parameters and resonance frequency of metallic thick resonators is presented. Two different topologies were studied: the original Pendry's SRR and spiral resonators of two and three turns. Theoretical computations of resonant frequencies are in good agreement with values obtained with a commercial electromagnetic solver. The model could be helpful for designing thick frequency selective surfaces (FSS) based on this types of resonators, so called metasurfaces.
Analysis, modeling, and simulation of series-parallel resonant converter circuits
Siu-Chung Wong; Andrew D. Brown
1995-01-01
This paper presents a SPICE macromodel for a generic series-parallel resonant converter circuit. The model is derived from the averaged time-invariant state-space equations obtained from a Fourier transform. The conditions are derived under which all but the fundamental harmonic may be discarded, and the model developed based solely on the fundamental Fourier component. The single macromodel developed has a wide
Modelling the short-circuit current of polymer bulk heterojunction solar cells
Wim Geens; Tom Martens; Jef Poortmans; Tom Aernouts; Jean Manca; Laurence Lutsen; Paul Heremans; Staf Borghs; Robert Mertens; Dirk Vanderzande
2004-01-01
An analytical model has been developed to estimate the short-circuit current density of conjugated polymer\\/fullerene bulk heterojunction solar cells. The model takes into account the solvent-dependent molecular morphology of the donor\\/acceptor blend, which was revealed by transmission electron microscopy. Field-effect transistors based on single and composite organic layers were fabricated to determine values for the charge carrier mobilities of such
EM-ANN models for microstrip vias and interconnects in dataset circuits
Paul M. Watson; Kuldip C. Gupta
1996-01-01
A novel approach for accurate and efficient modeling of monolithic microwave\\/millimeter wave integrated circuit (MMIC) components by using electromagnetically trained artificial neural network (EM-ANN) software modules is presented. Full-wave EM analysis is employed to characterize MMIC components. Structures for simulation are chosen using design of experiments (DOE) methodology. EM-ANN models are then trained using physical parameters as inputs and S-parameters
A 3-D model for concentrator solar cells based on distributed circuit units
Beatriz Galiana; Carlos Algora; Ignacio Rey-Stolle; Ivan García Vara
2005-01-01
A three-dimensional (3-D) distributed model for high-concentrator solar cells based on elementary units made up of electrical circuits is presented. The recombination mechanisms are dealt with in detail, paying special attention to the perimeter properties. No ohmic effect is omitted making this a powerful simulation tool for concentrator solar cells. A shunt resistance is also included. The model allows the
Distributed Circuit Modeling of Multilayer Capacitor Parameters Related to the Metal Film Layer
Robert W. Brown
2007-01-01
Linkage between the distributed-circuit capacitor model and multi-layer capacitor structures is demonstrated. Capacitor inductance leading to self-resonance in standard metallized polymer capacitors arises from lead and package inductance and can be represented by lumped inductance external to the capacitor modeling in this paper. Distributed internal capacitor inductance is negligible in metallized polymer capacitors for most applications and therefore is not
Modeling for infrared readout integrated circuit based on Verilog-A
NASA Astrophysics Data System (ADS)
Wang, Xiao; Shi, Zelin
2015-04-01
Infrared detectors are the core of infrared imaging systems, while readout integrated circuits are the key components of detectors. In order to grasp the performance of circuits quickly and accurately, a method of circuit modeling using Verilog-A language is proposed, which present a behavioral simulation model for the ROIC. At first, a typical capacitor trans-impedance amplifier(CTIA) ROIC unit is showed, then the two essential parts of it,operational amplifier and switch are modeled on behavioral level. The op amp model concludes these non-ideal factors, such as finite gain-bandwidth product, input and output offset, output resistance and so on. Non-deal factors that affect switches are considered in the switch behavioral model, such as rise and fall time, on-resistance and so on. At last time-domain modeling method for noise is presented, which is compared with the classical frequency domain method for difference. The analysis results shows that in the situation that noise interested bandwidth(NIBW) is more than 5MHz, the difference between the two methods leads to less than 1% if the sample rate of noise is larger 4 times of the NIBW
Daniel De Zutter; Frank Olyslager
1995-01-01
In the present contribution we construct a high-frequency circuit model for the excitation of eigenmodes in general waveguides due to externally impinging electromagnetic waves. The circuit model, consisting of distributed sources in a transmission line model, is based on Lorentz's reciprocity theorem. The classical quasi-TEM solution of this problem is found as a special case from the full-wave model. The
Total dose and dose rate models for bipolar transistors in circuit simulation.
Campbell, Phillip Montgomery; Wix, Steven D.
2013-05-01
The objective of this work is to develop a model for total dose effects in bipolar junction transistors for use in circuit simulation. The components of the model are an electrical model of device performance that includes the effects of trapped charge on device behavior, and a model that calculates the trapped charge densities in a specific device structure as a function of radiation dose and dose rate. Simulations based on this model are found to agree well with measurements on a number of devices for which data are available.
ERIC Educational Resources Information Center
Asami, Noriaki; King, Julien; Monk, Martin
2000-01-01
Focuses on the familiar problem of students' understanding of elementary electrical circuits from a much neglected point of view. Suggests that the patterning commonly found in students' ideas might have its roots in the cognitive processing with which students operate their mental models of d.c. electrical circuits. Studies Japanese 10-11 year…
The Circuit Theory Behind Coupled-Mode Magnetic Resonance-Based Wireless Power Transmission
Kiani, Mehdi; Ghovanloo, Maysam
2014-01-01
Inductive coupling is a viable scheme to wirelessly energize devices with a wide range of power requirements from nanowatts in radio frequency identification tags to milliwatts in implantable microelectronic devices, watts in mobile electronics, and kilowatts in electric cars. Several analytical methods for estimating the power transfer efficiency (PTE) across inductive power transmission links have been devised based on circuit and electromagnetic theories by electrical engineers and physicists, respectively. However, a direct side-by-side comparison between these two approaches is lacking. Here, we have analyzed the PTE of a pair of capacitively loaded inductors via reflected load theory (RLT) and compared it with a method known as coupled-mode theory (CMT). We have also derived PTE equations for multiple capacitively loaded inductors based on both RLT and CMT. We have proven that both methods basically result in the same set of equations in steady state and either method can be applied for short- or midrange coupling conditions. We have verified the accuracy of both methods through measurements, and also analyzed the transient response of a pair of capacitively loaded inductors. Our analysis shows that the CMT is only applicable to coils with high quality factor (Q) and large coupling distance. It simplifies the analysis by reducing the order of the differential equations by half compared to the circuit theory. PMID:24683368
The Circuit Theory Behind Coupled-Mode Magnetic Resonance-Based Wireless Power Transmission.
Kiani, Mehdi; Ghovanloo, Maysam
2012-09-01
Inductive coupling is a viable scheme to wirelessly energize devices with a wide range of power requirements from nanowatts in radio frequency identification tags to milliwatts in implantable microelectronic devices, watts in mobile electronics, and kilowatts in electric cars. Several analytical methods for estimating the power transfer efficiency (PTE) across inductive power transmission links have been devised based on circuit and electromagnetic theories by electrical engineers and physicists, respectively. However, a direct side-by-side comparison between these two approaches is lacking. Here, we have analyzed the PTE of a pair of capacitively loaded inductors via reflected load theory (RLT) and compared it with a method known as coupled-mode theory (CMT). We have also derived PTE equations for multiple capacitively loaded inductors based on both RLT and CMT. We have proven that both methods basically result in the same set of equations in steady state and either method can be applied for short- or midrange coupling conditions. We have verified the accuracy of both methods through measurements, and also analyzed the transient response of a pair of capacitively loaded inductors. Our analysis shows that the CMT is only applicable to coils with high quality factor (Q) and large coupling distance. It simplifies the analysis by reducing the order of the differential equations by half compared to the circuit theory. PMID:24683368
Modeling and analysis of integrated magnetic components
H. Njiende; N. Froehleke; W. A. Cronje
2003-01-01
A complete modeling approach of integrated magnetic components comprising a transformer and filter inductors is presented in this contribution, which is verified on a four winding component. Impacts of the center leg and outer leg air gaps on inductances, coupling factor and output current ripple are discussed. Analytical and FEM modeling results based on geometrical, material and winding data are
Accurate natural convection modelling for magnetic components
Vencislav Valchev; Alex Van Den Bossche
2003-01-01
An accurate presentation of convection heat transfer in magnetic components is proposed for isothermal surface approach. The presented improved modelling of convection heat transfer includes also the effects of the orientation of the component and the influence of the ambient temperature. The proposed modelling is verified by comparison with experimental data obtained for an experimental box shape. The carried out
Spin Circuit Model for Spin Orbit Torques in 2D Channels
NASA Astrophysics Data System (ADS)
Hong, Seokmin
2015-03-01
Recently, the unique coupling between charge and spin in topological insulators has been explored through various types of electrical measurements, which could have interesting applications. In this talk, we present a spin circuit model for spin orbit torques in topological insulator surface states and other 2D channels. We show with a simple example that results from the circuit model agree well with those obtained from nonequilibrium Green's function (NEGF) based quantum transport simulation. Some predictions of our model have already received experimental support and we hope this model can provide a unifying framework that can be used to critically evaluate experimental results, to explore new types of devices as well as to answer fundamental questions regarding these materials. The model for spin-orbit torques described here can be incorporated into a broader spin-circuit approach which, we believe, provides a natural platform for multi-physics, multi-component spintronic devices. This work was supported by FAME, a Semiconductor Research Corporation program sponsored by MARCO and DARPA.
Analytical model for magnetic components including self-heating effects
L. M. Escribano; R. Prieto; J. A. Oliver; J. A. Cobos; J. Uceda
2004-01-01
Analytical magnetic models are used when the winding strategy and the geometry of the magnetic component produces an 1D magnetic field distribution. Additionally, analytical thermal models can be used when thermal distribution, the geometries of the windings and the core produce an 1D heat flux distribution. This work shows how both thermal and magnetic analytical models can be coupled to
Equivalent Circuit Modeling for Carbon Nanotube Schottky Barrier Modulation in Polarized Gases
NASA Technical Reports Server (NTRS)
Yamada, Toshishige
2005-01-01
We study the carbon nanotube Schottky barrier at the metallic electrode interface in polarized gases using an equivalent circuit model. The gas-nanotube interaction is often weak and very little charge transfer is expected [l]. This is the case with'oxygen, but the gas-electrode interaction is appreciable and makes the oxygen molecules negatively charged. In the closed circuit condition, screening positive charges appear in the nanotube as well as in the electrode, and the Schottky barrier is modulated due to the resultant electrostatic effects [2]. In the case of ammonia, both the gas-nanotube and gas-electrode interactions are weak, but the Schottky barrier can still be modulated since the molecules are polarized and align in the preferred orientation within the gap between the electrode and nanotube in the open circuit condition (dipole layer formation). In the closed circuit condition, an electric field appears in the gap and strengthens or weakens the preferred dipole alignment reflecting the nanotube Fermi level. The modulation is visible when the nanotube depletion mode is involved, and the required dipole density is as low as 2 x 10(exp 13) dipoles/sq cm, which is quite feasible experimentally,
Design and Modeling of a 3-D Magnetic Actuator for Magnetic Microbead Manipulation.
Zhang, Zhipeng; Menq, Chia-Hsiang
2011-06-01
This paper presents the design, implementation, modeling, and analyses of a hexapole magnetic actuator that is capable of 3-D manipulation of a magnetic microbead. The magnetic actuator employs six sharp-tipped magnetic poles placed in hexapole configuration, six actuating coils, and a magnetic yoke. The magnetic poles concentrate the magnetic flux generated by the coils to the workspace, resulting in a high magnetic field with a large field gradient for magnetic force generation on the magnetic microbead. A lumped-parameter magnetic force model is then established to characterize nonlinearity of the magnetic force exerting on the magnetic microbead with respect to the applied currents to the coils and the position dependence of the magnetic force in the workspace. The force generation capability of the designed system is then explored using the force model. Moreover, an inverse force model is derived and its effect on the magnetic actuation capability is investigated. The inverse force model facilitates the implementation of a feedback control law to stabilize and control the motion of a magnetic microbead. Experimental results in terms of the magnetic force in relation to stable motion control of a magnetic microbead are used to validate the force model. PMID:24382943
Design and Modeling of a 3-D Magnetic Actuator for Magnetic Microbead Manipulation
Zhang, Zhipeng; Menq, Chia-Hsiang
2013-01-01
This paper presents the design, implementation, modeling, and analyses of a hexapole magnetic actuator that is capable of 3-D manipulation of a magnetic microbead. The magnetic actuator employs six sharp-tipped magnetic poles placed in hexapole configuration, six actuating coils, and a magnetic yoke. The magnetic poles concentrate the magnetic flux generated by the coils to the workspace, resulting in a high magnetic field with a large field gradient for magnetic force generation on the magnetic microbead. A lumped-parameter magnetic force model is then established to characterize nonlinearity of the magnetic force exerting on the magnetic microbead with respect to the applied currents to the coils and the position dependence of the magnetic force in the workspace. The force generation capability of the designed system is then explored using the force model. Moreover, an inverse force model is derived and its effect on the magnetic actuation capability is investigated. The inverse force model facilitates the implementation of a feedback control law to stabilize and control the motion of a magnetic microbead. Experimental results in terms of the magnetic force in relation to stable motion control of a magnetic microbead are used to validate the force model. PMID:24382943
NASA Astrophysics Data System (ADS)
Zhang, Bin; Mao, Lu-hong; Li, Shanguo; Guo, Wei-lian; Zhang, Shi-lin; Liang, Hui-lai
2008-01-01
As the length scale of the devices decreases, electrons will spend increasingly more of their time in the connections between components; this interconnectivity problem could restrict further increases in computer chip processing power and speed. Considerable effort is therefore being expended on the development of efficient silicon light-emitting devices compatible with silicon based integrated circuit technology. Here, we describe the electrical and optical properties of Silicon positive intrinsic negative (pin) structure diode that operates at room temperature. The voltage-current and electroluminescence (EL) property are measured at room temperature for a silicon pin diode under forward biased current. The optical spectral response of the system at 700nm indicates that the emitting light source has low optical loss in Silicon. So the LED is suitable for Silicon optoelectronic interconnection system.[1][2] The rate-equation model for free carriers on light-emitting pin structure and the equivalent circuit model based on it have been presented. We have developed a way to calculate the model parameters by comparison with experimental results. This parameter extraction way can be fully accomplished automatically by using MATHCAD program and the equivalent circuit model is simulated by using HSPICE program respectively. The results of both experiment and simulation results are good agreement with each other.
Empirical models of the magnetospheric magnetic field
NASA Astrophysics Data System (ADS)
Jordan, C. E.
1994-05-01
A general overview of magnetospheric modeling is given, along with a more detailed discussion of several empirical models which are widely used. These models are composed of representations of the Earth's main internal field (basically a bipolar field), plus external field contributions due to ring currents (carried by the particles in the Van Allen radiation belts), magnetopause currents (the boundary surface between the Earth's magnetic field and interplanetary magnetic field carried by the solar wind), and tail currents (carried by particles in the neutral sheet of the magnetotail). The empirical models presented here are the Mead-Fairfield, Olsen-Pfitzer tilt-dependent (1977), Tsyganenko-Usamo, Tsyganenko (1987), Olsen-Pfitzer dynamic (1988), Tsyganenko (1989), and Hilmer-Voight models. The derivations, agreement with quiet time and storm time data from the two satellite programs, Spacecraft Charging at High Altitudes (SCATHA) and Combined Release Radiation Effects Satellite (CRRES), and computational requirements of these models are compared.
Chunghyun Ryu; Daehyun Chung; Junho Lee; Kwangyong Lee; Taesung Oh; Joungho Kim
2005-01-01
In this paper, we firstly propose the high frequency equivalent circuit model of the chip-to-chip vertical via based on its physical configuration. The model parameters are extracted from the measurement of S-parameters using a vector network analyzer up to 20GHz frequency range. The proposed circuit model is verified experimentally in frequency and time domains. Furthermore, the high frequency characteristics of
A phenomenological constitutive model for magnetic shape memory alloys
Kiefer, Bjoern
2007-04-25
A thermodynamics-based constitutive model is derived which predicts the nonlinear strain and magnetization response that magnetic shape memory alloys (MSMAs) exhibit when subjected to mechanical and magnetic loads. The ...
Saturable Shielding-A Technique for Nonlinear Coupling in Magnetic Circuits
R. Berger; T. S. Crowther; J. I. Raffel
1966-01-01
If a magnetic film (the shield) with transverse saturation demagnetizing field Hd and anisotropy field Hk is placed in a transverse field below saturation strength (Hd+Hk), it experiences a net field less than Hk. A second film (the storage film), when placed on top of the first, will experience the same net field. If the anisotropy field of the storage
Accurate Cold-Test Model of Helical TWT Slow-Wave Circuits
NASA Technical Reports Server (NTRS)
Kory, Carol L.; Dayton, James A., Jr.
1997-01-01
Recently, a method has been established to accurately calculate cold-test data for helical slow-wave structures using the three-dimensional electromagnetic computer code, MAFIA. Cold-test parameters have been calculated for several helical traveling-wave tube (TWT) slow-wave circuits possessing various support rod configurations, and results are presented here showing excellent agreement with experiment. The helical models include tape thickness, dielectric support shapes and material properties consistent with the actual circuits. The cold-test data from this helical model can be used as input into large-signal helical TWT interaction codes making it possible, for the first time, to design a complete TWT via computer simulation.
Translating Non-Trivial Algorithms from the Circuit Model to the Measurement
Smith IV, Amos M [ORNL; Alsing, Paul [Air Force Research Laboratory; Lott, Capt. Gordon [Air Force Research Laboratory; Fanto, Michael [Air Force Research Laboratory
2015-01-01
We provide a set of prescriptions for implementing a circuit model algorithm as measurement based quantum computing via a large discrete cluster state constructed sequentially, from qubits implemented as single photons. We describe a large optical discrete graph state capable of searching logical 4 and 8 element lists as an example. To do so we have developed several prescriptions based on analytic evaluation of the evolution of discrete cluster states and graph state equations. We describe the cluster state as a sequence of repeated entanglement and measurement steps using a small number of single photons for each step. These prescriptions can be generalized to implement any logical circuit model operation with appropriate single photon measurements and feed forward error corrections. Such a cluster state is not guaranteed to be optimal (i.e. minimum number of photons, measurements, run time).
Gneiding, N., E-mail: Natalia.Gneiding@physik.uni-erlangen.de [Erlangen Graduate School in Advanced Optical Technologies (SAOT), University of Erlangen-Nuremberg, 91052 Erlangen (Germany); Zhuromskyy, O.; Peschel, U. [Institute of Optics, Information and Photonics, University of Erlangen-Nuremberg, 91058 Erlangen (Germany); Shamonina, E. [Department of Engineering Science, University of Oxford, Parks Road, OX1 3PJ Oxford (United Kingdom)
2014-10-28
Metamaterials are comprised of metallic structures with a strong response to incident electromagnetic radiation, like, for example, split ring resonators. The interaction of resonator ensembles with electromagnetic waves can be simulated with finite difference or finite elements algorithms, however, above a certain ensemble size simulations become inadmissibly time or memory consuming. Alternatively a circuit description of metamaterials, a well developed modelling tool at radio and microwave frequencies, allows to significantly increase the simulated ensemble size. This approach can be extended to the IR spectral range with an appropriate set of circuit element parameters accounting for physical effects such as electron inertia and finite conductivity. The model is verified by comparing the coupling coefficients with the ones obtained from the full wave numerical simulations, and used to optimize the nano-antenna design with improved radiation characteristics.
MYERS,DAVID R.; JESSING,JEFFREY R.; SPAHN,OLGA B.; SHANEYFELT,MARTY R.
2000-01-01
This project represented a coordinated LLNL-SNL collaboration to investigate the feasibility of developing radiation-hardened magnetic non-volatile memories using giant magnetoresistance (GMR) materials. The intent of this limited-duration study was to investigate whether giant magnetoresistance (GMR) materials similar to those used for magnetic tunnel junctions (MTJs) were process compatible with functioning CMOS circuits. Sandia's work on this project demonstrated that deposition of GMR materials did not affect the operation nor the radiation hardness of Sandia's rad-hard CMOS technology, nor did the integration of GMR materials and exposure to ionizing radiation affect the magnetic properties of the GMR films. Thus, following deposition of GMR films on rad-hard integrated circuits, both the circuits and the films survived ionizing radiation levels consistent with DOE mission requirements. Furthermore, Sandia developed techniques to pattern deposited GMR films without degrading the completed integrated circuits upon which they were deposited. The present feasibility study demonstrated all the necessary processing elements to allow fabrication of the non-volatile memory elements onto an existing CMOS chip, and even allow the use of embedded (on-chip) non-volatile memories for system-on-a-chip applications, even in demanding radiation environments. However, funding agencies DTRA, AIM, and DARPA did not have any funds available to support the required follow-on technology development projects that would have been required to develop functioning prototype circuits, nor were such funds available from LDRD nor from other DOE program funds.
Prototype model for automatic integrated circuit bonding inspection
NASA Astrophysics Data System (ADS)
Rajeswari, Mandava; Saravanan, K.
1995-07-01
A simple but comprehensive prototype model developed to automate the inspection of wedge bonds in the IC assembly process is described. The defects associated with the bond quality are classified into four categories: size, shape, position, and dimension. The bond is inspected sequentially for each category of defects and is rejected without further processing when any defect is detected. The procedure adopted in the prototype is as follows. A global thresholding technique automatically binarizes the intensity image of the bond. Simple features such as the pixel count, minimum enclosing rectangle, centroid, and median are used to verify the specifications related to the size and shape. An intelligent scanning technique inspects the position-related specifications in addition to identifying the wire and tail positions of the bond. The dimensions of the bond are determined using projection information. Most importantly, this model is capable of determining the wire position, which is useful in inspecting wire- related defects. Experiments conducted on actual sample ICs have shown a 100% success rate.
NASA Astrophysics Data System (ADS)
Xavier, Marcelo A.; Trimboli, M. Scott
2015-07-01
This paper introduces a novel application of model predictive control (MPC) to cell-level charging of a lithium-ion battery utilizing an equivalent circuit model of battery dynamics. The approach employs a modified form of the MPC algorithm that caters for direct feed-though signals in order to model near-instantaneous battery ohmic resistance. The implementation utilizes a 2nd-order equivalent circuit discrete-time state-space model based on actual cell parameters; the control methodology is used to compute a fast charging profile that respects input, output, and state constraints. Results show that MPC is well-suited to the dynamics of the battery control problem and further suggest significant performance improvements might be achieved by extending the result to electrochemical models.
Noise in SiGe HBT RF Technology: Physics, Modeling, and Circuit Implications
GUOFU NIU
2005-01-01
This paper presents an overview of the physics, modeling, and circuit implications of RF broad-band noise, low-frequency noise, and oscillator phase noise in SiGe heterojunction bipolar transistor (HBT) RF technology. The ability to simultaneously achieve high cutoff frequency (fT), low base resistance (rb), and high current gain (?) using Si processing underlies the low levels of low-frequency 1\\/f noise, RF
Highly localized Wannier functions for the efficient modeling of photonic crystal circuits
Matthias Schillinger; Sergei F. Mingaleev; Daniel Hermann; Kurt Busch
2005-01-01
We present a novel approach for the accurate and efficient modeling of photonic crystal-based integrated optical circuits. Within this approach, the electromagnetic field is expanded into an orthogonal basis of highly localized Wannier functions, which reduces Maxwell's equations to low-rank eigenvalue problems (for defect mode and waveguide dispersion calculations) or to sparse systems of linear equations (for transmission\\/reflection calculations through\\/from
Circuit models applied to the design of a novel uncooled infrared focal plane array structure
Shali Shi; Dapeng Chen; Chaobo Li; Binbin Jiao; Yi Ou; Yupeng Jing; Tianchun Ye; Zheying Guo; Qingchuan Zhang; Xiaoping Wu
2007-01-01
This paper describes a circuit model applied to the simulation of the thermal response frequency of a novel substrate-free single-layer bi-material cantilever microstructure used as the focal plane array (FPA) in an uncooled opto-mechanical infrared imaging system. In order to obtain a high detection of the IR object, gold (Au) is coated alternately on the silicon nitride (SiNx) cantilevers of
A circuit-compatible model of ballistic carbon nanotube field-effect transistors
Arijit Raychowdhury; Saibal Mukhopadhyay; Kaushik Roy
2004-01-01
Carbon nanotube field-effect transistors (CNFETs) are being extensively studied as possible successors to CMOS. Novel device structures have been fabricated and device simulators have been developed to estimate their performance in a sub-10-nm transistor era. This paper presents a novel method of circuit-compatible modeling of single-walled semiconducting CNFETs in their ultimate performance limit. For the first time, both the I-V
The interplay of plasticity and adaptation in neural circuits: a generative model
Bernacchia, Alberto
2014-01-01
Multiple neural and synaptic phenomena take place in the brain. They operate over a broad range of timescales, and the consequences of their interplay are still unclear. In this work, I study a computational model of a recurrent neural network in which two dynamic processes take place: sensory adaptation and synaptic plasticity. Both phenomena are ubiquitous in the brain, but their dynamic interplay has not been investigated. I show that when both processes are included, the neural circuit is able to perform a specific computation: it becomes a generative model for certain distributions of input stimuli. The neural circuit is able to generate spontaneous patterns of activity that reproduce exactly the probability distribution of experienced stimuli. In particular, the landscape of the phase space includes a large number of stable states (attractors) that sample precisely this prior distribution. This work demonstrates that the interplay between distinct dynamical processes gives rise to useful computation, and proposes a framework in which neural circuit models for Bayesian inference may be developed in the future. PMID:25400577
Modeling Solar Magnetic Fields Using Satellite Data
NASA Astrophysics Data System (ADS)
Lee, G.; Malanushenko, A. V.; DeRosa, M. L.
2014-12-01
Previous research reconstructed a three-dimensional model of the magnetic field of an active region on the Sun from using solar coronal loops as guides for modeling(Malanushenko et al., ApJ,2009, 707:1044). In this study, we test the consistency of such reconstructions with data from the Atmospheric Imaging Assembly (AIA) and the Helioseismic and Magnetic Imager (HMI) by applying the aformentioned method to additional active regions with varying amounts of solar activity. To create an initial model of a magnetic field surrounding an active region, we first manually trace the coronal loops on the coronal images in the following wavelengths: 171Å, 193Å, 211Å, 94Å, 131Å, and 335Å. The manually traced loops are then used as a guide for a computer reconstruction of the individual three-dimensional field lines with differing heights and degrees of local twist. The reconstructed field lines are then adjusted by a partially automated algorithm, so that the constructed field line would correspond to a coronal loop on the Sun. These fitted loops serve as a skeleton to create a model of the magnetic field of the active region. We expect that our modeling can be used in future works to predict future solar events. Implications of this ability include being able to prepare a response for a solar event before it happens.
Bhunia, Swarup
IEEE TRANSACTIONS ON COMPUTER-AIDED DESIGN OF INTEGRATED CIRCUITS AND SYSTEMS, VOL. 25, NO. 11, NOVEMBER 2006 2427 Delay Modeling and Statistical Design of Pipelined Circuit Under Process Variation, the delay of a pipelined circuit follows a statistical distribution. This paper presents analytical models
Bipolar junction transistor models for circuit simulation of cosmic-ray-induced soft errors
NASA Technical Reports Server (NTRS)
Benumof, R.; Zoutendyk, J.
1984-01-01
This paper examines bipolar junction transistor models suitable for calculating the effects of large excursions of some of the variables determining the operation of a transistor. Both the Ebers-Moll and Gummel-Poon models are studied, and the junction and diffusion capacitances are evaluated on the basis of the latter model. The most interesting result of this analysis is that a bipolar junction transistor when struck by a cosmic particle may cause a single event upset in an electronic circuit if the transistor is operated at a low forward base-emitter bias.
Large Signal Circuit Model of Two-Section Gain Lever Quantum Dot Laser
NASA Astrophysics Data System (ADS)
Ashkan, Horri; Seyedeh Zahra, Mirmoeini; Rahim, Faez
2012-11-01
An equivalent circuit model for the design and analysis of two-section gain lever quantum dot (QD) laser is presented. This model is based on the three level rate equations with two independent carrier populations and a single longitudinal optical mode. By using the presented model, the effect of gain lever on QD laser performances is investigated. The results of simulation show that the main characteristics of laser such as threshold current, transient response, output power and modulation response are affected by differential gain ratios between the two-sections.
NASA Astrophysics Data System (ADS)
Owens, Mathew; Scott, Chris; Lockwood, Mike; Barnard, Luke; Harrison, Giles; Nicoll, Keri; Watt, Clare; Bennett, Alec
2015-04-01
Observational studies have reported solar magnetic modulation of terrestrial lightning on a range of time scales, from days to decades. The proposed mechanism is two-step: lightning rates vary with galactic cosmic ray (GCR) flux incident on Earth, either via changes in atmospheric conductivity and/or direct triggering of lightning. GCR flux is, in turn, primarily controlled by the heliospheric magnetic field (HMF) intensity. Consequently, global changes in lightning rates are expected. This study instead considers HMF polarity, which doesn't greatly affect total GCR flux. Opposing HMF polarities are, however, associated with a 40 to 60% difference in observed UK lightning and thunder rates. As HMF polarity skews the terrestrial magnetosphere from its nominal position, this perturbs local ionospheric potential at high latitudes and local exposure to energetic charged particles from the magnetosphere. We speculate as to the mechanism(s) by which this may, in turn, redistribute the global location and/or intensity of thunderstorm activity.
Reentrant excitation in an analog-digital hybrid circuit model of cardiac tissue
NASA Astrophysics Data System (ADS)
Mahmud, Farhanahani; Shiozawa, Naruhiro; Makikawa, Masaaki; Nomura, Taishin
2011-06-01
We propose an analog-digital hybrid circuit model of one-dimensional cardiac tissue with hardware implementation that allows us to perform real-time simulations of spatially conducting cardiac action potentials. Each active nodal compartment of the tissue model is designed using analog circuits and a dsPIC microcontroller, by which the time-dependent and time-independent nonlinear current-voltage relationships of six types of ion channel currents employed in the Luo-Rudy phase I (LR-I) model for a single mammalian cardiac ventricular cell can be reproduced quantitatively. Here, we perform real-time simulations of reentrant excitation conduction in a ring-shaped tissue model that includes eighty nodal compartments. In particular, we show that the hybrid tissue model can exhibit real-time dynamics for initiation of reentries induced by uni-directional block, as well as those for phase resetting that leads to annihilation of the reentry in response to impulsive current stimulations at appropriate nodes and timings. The dynamics of the hybrid model are comparable to those of a spatially distributed tissue model with LR-I compartments. Thus, it is conceivable that the hybrid model might be a useful tool for large scale simulations of cardiac tissue dynamics, as an alternative to numerical simulations, leading toward further understanding of the reentrant mechanisms.
Lu, Xiang
2006-04-12
Delay test in nano-scale VLSI circuits becomes more difficult with shrinking technology feature sizes and rising clock frequencies. In this dissertation, we study three challenging issues in delay test: fault modeling, ...
Lei Zhu; Ke Wu
1999-01-01
Unified dynamic equivalent-circuit model for characterizing planar unbounded discontinuities is reported for use in the field-theory-based computer-aided design and optimization of high-frequency integrated circuits and structures such as monolithic and hybrid microwave integrated circuits (M(H)MIC's). The proposal of the circuit model is stemmed from a new scheme called the short-open calibration (SOC) technique. This SOC technique is directly accommodated in
Modelling of rotational magnetization in anisotropic sheets
Witold Mazgaj
2011-01-01
Purpose – The aim of this paper is to present a new relatively simple model of the rotational magnetization process in anisotropic sheets. Design\\/methodology\\/approach – The surface of a sample of an anisotropic sheet is divided into an assumed number of specified directions. To each direction a certain hysteresis loop, the so-called direction hysteresis, is assigned. The parameters of the
Modeling Magnetic Structures in the Inner Heliosphere
NASA Astrophysics Data System (ADS)
Odstrcil, D.; Bourdelle, A.; Kunkel, V.; Rouillard, A. P.; Vandas, M.
2014-12-01
Currently, the WSA-ENLIL-Cone modeling system is used by various space weather agencies for operational forecasting of corotating and transient solar wind disturbances in the inner heliosphere. This modeling system provides global context and arrival times of the solar wind streams and coronal mass ejections (CMEs) to Earth, planets, and spacecraft. Such predictions are running continuously and much faster than real time. However, CME-like disturbances are generated by launching hydrodynamic transients and thus it is not possible to predict the southward magnetic field (-Bz). In this presentation, we use 3-D analytic models of spheromaks and flux ropes, launch them into the background solar wind at 0.1 AU and simulate their evolution in the inner heliosphere. We discuss differences between these two models and effects of the background magnetic field on their propagation and distortion.
Supercapacitor equivalent electrical circuit model based on charges redistribution by diffusion
NASA Astrophysics Data System (ADS)
Sedlakova, Vlasta; Sikula, Josef; Majzner, Jiri; Sedlak, Petr; Kuparowitz, Tomas; Buergler, Brandon; Vasina, Petr
2015-07-01
A new method for the determination of parameters for an equivalent electrical circuit model of supercapacitors is proposed. The method is based on the evaluation of the time dependence of voltage measured on the supercapacitor terminals after its charging by a defined current pulse. The measured time dependence of the voltage is fitted by an exponential function, where the exponent is proportional to the square root of time. This term reflects the redistribution of charges by diffusion inside the supercapacitor structure. The equivalent electrical circuit of supercapacitors is described by five parameters - two capacitors and three resistors. One capacitor corresponds to the Helmholtz capacitance, which is charged immediately with the time constant in the order of hundreds milliseconds, while the second one represents the diffuse capacitance, which is charged with the time constant in the order of hundreds seconds. The two resistors in the equivalent circuit model represent the equivalent series resistance and the leakage resistance, respectively, while the third resistor describes the resistance for charge diffusion in the supercapacitor structure. This resistance is time dependent and a way for calculating its value is demonstrated.
Finite element analysis in electromagnetic systems-accounting for electric circuits
Francis Piriou; Adel Razek
1993-01-01
Two approaches for the numerical simulation of electromagnetic systems, accounting for electric circuit equations, are presented. First, the indirect coupled model, which permits the simulation of synchronous machines fed by controlled inverters with moderate calculation time is considered. Second, a direct coupled model where the magnetic and electric circuit equations (2-D or 3-D) are solved simultaneously is developed. This approach
Quark matter under strong magnetic fields in chiral models
Rabhi, Aziz [Centro de Fisica Computacional, Department of Physics, University of Coimbra, P-3004-516 Coimbra (Portugal); Laboratoire de Physique de la Matiere Condensee, Faculte des Sciences de Tunis, Campus Universitaire, Le Belvedere-1060 (Tunisia); Providencia, Constanca [Centro de Fisica Computacional, Department of Physics, University of Coimbra, P-3004-516 Coimbra (Portugal)
2011-05-15
The chiral model is used to describe quark matter under strong magnetic fields and is compared to other models, the MIT bag model and the two-flavor Nambu-Jona-Lasinio model. The effect of vacuum corrections due to the magnetic field is discussed. It is shown that if the magnetic-field vacuum corrections are not taken into account explicitly, the parameters of the models should be fitted to low-density meson properties in the presence of the magnetic field.
Quark matter under strong magnetic field in chiral models
Aziz Rabhi; Constança Providência
2011-04-08
The chiral model is used to describe quark matter under strong magnetic fields and compared to other models, the MIT bag model and the two flavors Nambu-Jona-Lasinio model. The effect of vacuum corrections due to the magnetic field is discussed. It is shown that if the magnetic field vacuum corrections are not taken into account explicitly the parameters of the models should be fitted to low density meson properties in the presence of the magnetic field.
Yong-Ju Kim; Han-Sub Yoon; Seongsoo Lee; Gyu Moon; Joungho Kim; Jae-Kyung Wee
2004-01-01
In high-speed printed circuit boards, the decoupling capacitors are commonly used to mitigate the power-bus noise that causes many signal integrity problems. It is very important to determine their proper locations and values so that the power distribution network should have low impedance over a wide range of frequencies, which demands a precise power-bus model considering the decoupling capacitors. However,
Magnetic Testing, and Modeling, Simulation and Analysis for Space Applications
NASA Technical Reports Server (NTRS)
Boghosian, Mary; Narvaez, Pablo; Herman, Ray
2012-01-01
The Aerospace Corporation (Aerospace) and Lockheed Martin Space Systems (LMSS) participated with Jet Propulsion Laboratory (JPL) in the implementation of a magnetic cleanliness program of the NASA/JPL JUNO mission. The magnetic cleanliness program was applied from early flight system development up through system level environmental testing. The JUNO magnetic cleanliness program required setting-up a specialized magnetic test facility at Lockheed Martin Space Systems for testing the flight system and a testing program with facility for testing system parts and subsystems at JPL. The magnetic modeling, simulation and analysis capability was set up and performed by Aerospace to provide qualitative and quantitative magnetic assessments of the magnetic parts, components, and subsystems prior to or in lieu of magnetic tests. Because of the sensitive nature of the fields and particles scientific measurements being conducted by the JUNO space mission to Jupiter, the imposition of stringent magnetic control specifications required a magnetic control program to ensure that the spacecraft's science magnetometers and plasma wave search coil were not magnetically contaminated by flight system magnetic interferences. With Aerospace's magnetic modeling, simulation and analysis and JPL's system modeling and testing approach, and LMSS's test support, the project achieved a cost effective approach to achieving a magnetically clean spacecraft. This paper presents lessons learned from the JUNO magnetic testing approach and Aerospace's modeling, simulation and analysis activities used to solve problems such as remnant magnetization, performance of hard and soft magnetic materials within the targeted space system in applied external magnetic fields.
Multiscale Modeling of Solar Coronal Magnetic Reconnection
NASA Technical Reports Server (NTRS)
Antiochos, Spiro K.; Karpen, Judith T.; DeVore, C. Richard
2010-01-01
Magnetic reconnection is widely believed to be the primary process by which the magnetic field releases energy to plasma in the Sun's corona. For example, in the breakout model for the initiation of coronal mass ejections/eruptive flares, reconnection is responsible for the catastrophic destabilizing of magnetic force balance in the corona, leading to explosive energy release. A critical requirement for the reconnection is that it have a "switch-on' nature in that the reconnection stays off until a large store of magnetic free energy has built up, and then it turn on abruptly and stay on until most of this free energy has been released. We discuss the implications of this requirement for reconnection in the context of the breakout model for CMEs/flares. We argue that it imposes stringent constraints on the properties of the flux breaking mechanism, which is expected to operate in the corona on kinetic scales. We present numerical simulations demonstrating how the reconnection and the eruption depend on the effective resistivity, i.e., the effective Lundquist number, and propose a model for incorporating kinetic flux-breaking mechanisms into MHO calculation of CMEs/flares.
NASA Technical Reports Server (NTRS)
Balakrishna, S.; Goglia, G. L.
1979-01-01
The details of the efforts to synthesize a control-compatible multivariable model of a liquid nitrogen cooled, gaseous nitrogen operated, closed circuit, cryogenic pressure tunnel are presented. The synthesized model was transformed into a real-time cryogenic tunnel simulator, and this model is validated by comparing the model responses to the actual tunnel responses of the 0.3 m transonic cryogenic tunnel, using the quasi-steady-state and the transient responses of the model and the tunnel. The global nature of the simple, explicit, lumped multivariable model of a closed circuit cryogenic tunnel is demonstrated.
Modeling Magnetic Torque and Force for Controlled Manipulation of Soft-Magnetic Bodies
Jake J. Abbott; Olgaç Ergeneman; Michael P. Kummer; Ann M. Hirt; Bradley J. Nelson
2007-01-01
We calculate the torque and force generated by an arbitrary magneticfield on an axially symmetric soft-magnetic body. We consider the magnetization of the body as a function of the applied field, using a con- tinuous model that unifies two disparate magnetic models. The continuous torque and force follow. The model is verified experimentally, and captures the often neglected region between
Two-phase forward converter using an integrated magnetic component
Leung-Pong Wong; Yim-Shu Lee; DAVID KI-WAI CHENG; MARTIN H. L. CHOW
2004-01-01
An interleaved two-phase forward converter using an integrated magnetic component is proposed for telecommunication and computer applications. The integrated magnetic component consists of two step-down transformers and two output-filtering inductors on a single magnetic core. The z-parameter (gyrator) model and the equivalent-circuit model of the integrated magnetic component are presented. The circuit operation and design criteria of the proposed converter
NASA Technical Reports Server (NTRS)
1976-01-01
Twenty-nine circuits and circuit techniques developed for communications and instrumentation technology are described. Topics include pulse-code modulation, phase-locked loops, data coding, data recording, detection circuits, logic circuits, oscillators, and amplifiers.
C. F. Gilbert; D. Parks; J. E. Rauch; E. Waisman
1999-01-01
The authors describe their use of analog behavioral modeling techniques to develop physical system models of plasma opening switches, plasma radiation sources and bremsstrahlung diode radiation sources. A commercially available electronic circuit analysis software program is used as the programming environment for the models, and as the calculation engine for the system. The models are created as macros, which are
Kondo model with magnetic anisotropy terms for magnetic impurities on surfaces
?itko, Rok
Kondo model with magnetic anisotropy terms for magnetic impurities on surfaces Rok Zitko, Robert (Cu) with a decoupling layer (CuN) behave as high-spin Kondo impurities with strong magnetic direction-dependent shifts of magnetic excita- tions and direction-dependent splitting of the Kondo
Transport Properties of Soils and Spectral Electrical Response: Equivalent Circuit Models
NASA Astrophysics Data System (ADS)
Boadu, F. K.
2002-05-01
Non-invasive prediction of hydraulic properties of soils (hydraulic conductivity, porosity, and degree of saturation) from surface measurement techniques as provided by geophysical methods is appealing to geoscientists involved in groundwater and pollution control problems. There is the need, however, to understand how the hydraulic properties of soil influence their spectral electrical response (SER). Laboratory measurements of the spectral electrical response of over 30 soil samples taken from different sites across North Carolina were performed within the frequency range from 0.01 Hz to 10 kHz. The hydraulic conductivity, porosity, and moisture content of each soil sample were measured. Both the moisture content and the degree of compaction were controlled for each soil sample to simulate field conditions. The SER measurements are used to estimate the hydraulic conductivity and porosity of soils. The SER of a soil is modeled as a heterogeneous multiphase system using an equivalent circuit model. The intrinsic parameters, which describe the response of the model, are retrieved by an inversion scheme and are used in empirical regression models to predict the hydraulic conductivity and porosity. Multiple regression analyses suggest that the porosity and permeability can be well predicted by the parameters of the equivalent circuit model. Such direct relationships between parameters characterizing the spectral electrical response of soils and their hydraulic properties may provide versatile non-invasive methodology of obtaining hydraulic conductivity and porosity of soils using geophysical measurements.
Modeling and optimization of end section of MFISC model magnet
NASA Astrophysics Data System (ADS)
Ikäheimo, Jouni
1996-05-01
A mathematical model for the end section of a superconducting dipole magnet coil is presented. Magnetic field calculation methods concerning the evaluation of the flux density produced by the coil and the ferromagnetic yoke are discussed. The validity of the results is tested using finite element methods. The end section is optimized to have a peak flux density lower than 93% of that in the straight section. The integrated multipole analysis is in addition carried out.
NASA Astrophysics Data System (ADS)
Li, X. P.; Zhao, Z. J.; Oh, T. B.; Seet, H. L.; Neo, B. H.; Koh, S. J.
2004-06-01
A novel micro magnetic sensor called the Current Driven Magnetic Permeability Interference (CDMPI) sensor has been developed and the key parameters of the sensor have been studied. The sensor consists of a sensing element in a form of composite wire of a 20 m copper core electrodeposited with a thin layer of soft magnetic material (Ni80Fe20), an ac power source driving the permeability of the magnetic coating layer of the sensing element into a dynamic state, and a signal pickup LC circuit formed by a pickup coil and an capacitor. Experimental studies on the CDMPI sensor have been carried out to investigate the key parameteres in relation to the sensor sensitivity and resolution. The results showed that for high sensitivity and resolution, the frequency and magnitude of the ac driving current through the sensing element each has an optimum value, the resonance frequency of the signal pickup LC circuit should be equal to or twice as the driving frequency on the sensing element, and the anisotropy of the magnetic coating layer of the sensing wire element should be longitudinal.
EC5135: Analog Electronic Circuits EC3102: Analog Circuits
Krishnapura, Nagendra
transforms, frequency response Differential equations EC1010: Electrical and Magnetic Circuits EC2102EC5135: Analog Electronic Circuits EC3102: Analog Circuits Introduction Aniruddhan S Nagendra Krishnapura https://courses.iitm.ac.in Department of Electrical Engineering Indian Institute of Technology
Sammoura, Firas; Kim, Sang-Gook
2012-05-01
An electric circuit model for a circular bimorph piezoelectric micromachined ultrasonic transducer (PMUT) was developed for the first time. The model was made up of an electric mesh, which was coupled to a mechanical mesh via a transformer element. The bimorph PMUT consisted of two piezoelectric layers of the same material, having equal thicknesses, and sandwiched between three thin electrodes. The piezoelectric layers, having the same poling axis, were biased with electric potentials of the same magnitude but opposite polarity. The strain mismatches between the two layers created by the converse piezoelectric effect caused the membrane to vibrate and, hence, transmit a pressure wave. Upon receiving the echo of the acoustic wave, the membrane deformation led to the generation of electric charges as a result of the direct piezoelectric phenomenon. The membrane angular velocity and electric current were related to the applied electric field, the impinging acoustic pressure, and the moment at the edge of the membrane using two canonical equations. The transduction coefficients from the electrical to the mechanical domain and vice-versa were shown to be bilateral and the system was shown to be reversible. The circuit parameters of the derived model were extracted, including the transformer ratio, the clamped electric impedance, the spring-softening impedance, and the open-circuit mechanical impedance. The theoretical model was fully examined by generating the electrical input impedance and average plate displacement curves versus frequency under both air and water loading conditions. A PMUT composed of piezoelectric material with a lossy dielectric was also investigated and the maximum possible electroacoustical conversion efficiency was calculated. PMID:22622984
Hammerstrom, Dan
has the best performance/price in both nonspiking and spiking neural models. However, these circuits2502 IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS--I: REGULAR PAPERS, VOL. 54, NO. 11, NOVEMBER 2007 with and without nanoscale circuits. In this analysis we explore the time multiplexing of computational hardware
NASA Astrophysics Data System (ADS)
Zhou, Hao-Miao; Li, Chao; Xuan, Li-Ming; Wei, Jing; Zhao, Ji-Xiang
2011-03-01
This paper analyzes the magnetoelectric (ME) response around the resonance frequency in the magnetostrictive/piezoelectric/magnetostrictive (MPM) magnetoelectric laminate composites. Following the equivalent circuit method and considering the mechanical loss, we select the nonlinear magnetostrictive constitutive model to present a novel explicit nonlinear expression for the resonant magnetoelectric (ME) coefficient of the magnetoelectric laminate composites. Compared with the experimental results, the predicted resonant ME coefficient of the explicit expression shows a good agreement both qualitatively and quantitatively. Also, when the electromechanical coupling factor of the piezoelectric material, k31p, is small, this explicit expression can be reduced to the existing model. On this basis, this paper considers and predicts the magnetoelectric conversion characteristics of the magnetoelectric laminate composites, calculates and analyzes the influences of the thickness ratio of magnetostrictive layer and piezoelectric material, bias magnetic field, and saturation magnetostrictive coefficient on the resonant ME coefficient. This research can provide a theoretical basis for the preparation of magnetoelectric devices with good magnetoelectric conversion characteristics, such as magnetoelectric sensors, energy harvesting transducers, microwave devices etc.
Mcconaghy, Trent; Gielen, Georges
2011-01-01
This paper presents a method to automatically generate compact symbolic performance models of analog circuits with no prior specification of an equation template. The approach takes SPICE simulation data as input, which enables modeling of any nonlinear circuits and circuit characteristics. Genetic programming is applied as a means of traversing the space of possible symbolic expressions. A grammar is specially designed to constrain the search to a canonical form for functions. Novel evolutionary search operators are designed to exploit the structure of the grammar. The approach generates a set of symbolic models which collectively provide a tradeoff between error and model complexity. Experimental results show that the symbolic models generated are compact and easy to understand, making this an effective method for aiding understanding in analog design. The models also demonstrate better prediction quality than posynomials.
Modeling of a claw-pole alternator using permeance network coupled with electric circuits
M. Hecquet; P. Brochet
1995-01-01
We propose in this paper, a modeling and simulation method of electrical machines by electric-magnetic coupled network, based on the Bond-Graph models and permeance network. The proposed approach allows us to easily take into account nonlinearities such as saturation and simple hysteresis effects, and to obtain forces applied on the teeth, with a simulation time very weak compared to the
Dynamic Modeling of Soft Magnetic Film Actuated Scanners
Serhan O. Isikman; Hakan Urey
2009-01-01
Dynamic behavior of magnetic thin film actuators is investigated in detail and applied to various laser scanning applications. Magnetic hysteresis effects are incorporated into the model developed in the prior work, which assumes linear magnetization as a function of magnetic field and is based on the distributed point-by-point calculation of the magnetostatic moments and forces across the film surface. A
NASA Astrophysics Data System (ADS)
Mertz, Benjamin E.
Single dielectric barrier discharge (SDBD) plasma actuators have been applied to a wide variety of aerodynamic flow control applications ranging from stall suppression of airfoils at high angles of attack to reducing tip leakage in jet engine turbine blades. With increased interest in applying plasma actuators to various engineering problems comes the need for an efficient model of the actuators that can be used in a CFD simulation. Prior to the current work, a model was developed that captured many of the spatial and temporal dynamics of the actuator by using circuits consisting of resistors and capacitors to model the plasma and dielectric material. In the current work, this model was refined by casting the governing equations in terms of a generalized coordinate system so that it can be applied to curved surfaces, the grid dependence of the model was eliminated, and the method of applying this model as a boundary condition to the electrostatic equations to calculate the body forces generated by the actuator was studied. This new formulation of the lumped circuit element model was then validated against various experimental observations including force vector orientation needed to produce observed induced flow, the scaling of the force with input voltage, and the directivity patterns and pressure time-series from acoustic measurements. The model was also implemented in a flow solver for the case of an impulsively started actuator on a flat plate and compared to experimental data found in literature. Finally, the utility of the model was demonstrated by simulating the use of actuators for flow control of the flow over a circular cylinder and a modified blunt trailing edge wind turbine blade.
Abelian model of gravitating magnetic monopole
NASA Astrophysics Data System (ADS)
Bleyer, U.; Nikolaenko, V. M.
1985-12-01
A self-consistent U(1)-gauge model in gravitational field is investigated. The exact solutions for two types of corresponding field equations are obtained. These solutions can be interpreted as magnetic monopoles. The first solution is regular geometry, the second one has a physical singularity. In order to guarantee the stability of the monopoles the notion of a gravitational topological change based on de Rham's cohomology theory is introduced. This topological charge describes the sizes and the inner structure of the monopole.
The Working of Circuit Breakers Within Percolation Models for Financial Markets
NASA Astrophysics Data System (ADS)
Ehrenstein, Gudrun; Westerhoff, Frank
We use a modified Cont-Bouchaud model to explore the effectiveness of trading breaks. The modifications include that the trading activity of the market participants depends positively on historical volatility and that the orders of the agents are conditioned on the observed mispricing. Trading breaks, also called circuit breakers, interrupt the trading process when prices are about to exceed a pre-specified limit. We find that trading breaks are a useful instrument to stabilize financial markets. In particular, trading breaks may reduce price volatility and deviations from fundamentals.
Jie Chen; Ruobing Zhang; Jianfu Xiao; Liming Wang; Zhicheng Guan
2011-01-01
In this paper, the method of reducing the rise time of high-voltage pulse transformer output rectangular pulses using a magnetic compression switch has been studied. An equivalent circuit consisting of pulse transformer and magnetic switch was used to describe the behavior of a transformer operating with magnetic switch. Meanwhile, four simplified equivalent sub-circuits and corresponding differential calculation models were used
Modelling hysteresis in magnetically ordered materials
NASA Astrophysics Data System (ADS)
Song, Tiancheng
2003-06-01
This thesis presents a generalized version of the Preisach model of hysteresis which is designed to describe the temperature dependence and field dependence of the irreversible response of magnetically ordered materials everywhere below their critical temperature Tc. The model decomposes the magnetizing process into a sequence of Barkhausen events, each of which is represented by a double well potential with moment mu two states ? = +/-mu, a dissipation energy Wd = mu hc and a stored energy Ws = 2muhi. A given magnetic material is characterized by an ensemble of Barkhausen elements with a distribution of characteristic fields p(hc, hi). The distribution is allowed to vary with temperature in order to reflect intrinsic variations with temperature of the anisotropy and pinning mechanisms, in such a way that the coercive field distribution collapses into a delta-function delta( hc) as T approaches Tc from below. Thermal fluctuations are represented by a thermal viscosity field h*T = (kBT/mu)ln( texp/tau0). The model was used to simulate numerically various standard experimental response functions, including the temperature dependence of the zero field cooled moment in a fixed applied field ha, the temperature dependence of the field cooled moment in a fixed applied field, initial magnetizing and major hysteresis loop isotherms, and remanences, and the influence of each model parameter on the magnetic response functions was studied systematically. The model simulation sidentified the ratio eta of the mean zero temperature dissipation barrier W¯d(0) to the critical thermal fluctuation energy Wc = k BTcln(texp/tau 0) ass an important parameter which influences the principal structural characteristics of the response, and which can be used to classify materials as fluctuation-dominated or anisotropy-dominated. The model was applied to the analysis of the measured response functions five systems, two nanoparticulate systems, Fe/SiO 2 and NiFe2O 4, which were fluctuation-dominated, and three ferromagnetic perovskites SrRuO3, La0.5Sr 0.5-CoO3, and La0.7 Sr0.3MnO3, which were anisotropy-dominated. The analysis yielded the spectrum of Barkhausen characteristic fields p(hc, hi, T) and the Barkhausen moment mu(T), from which it is possible to reconstruct a physical picture of the evolution of the Barkhausen free energy barriers with temperature, as well as some description of the reversible component of the response.
An improved electrical and thermal model of a microbolometer for electronic circuit simulation
NASA Astrophysics Data System (ADS)
Würfel, D.; Vogt, H.
2012-09-01
The need for uncooled infrared focal plane arrays (IRFPA) for imaging systems has increased since the beginning of the nineties. Examples for the application of IRFPAs are thermography, pedestrian detection for automotives, fire fighting, and infrared spectroscopy. It is very important to have a correct electro-optical model for the simulation of the microbolometer during the development of the readout integrated circuit (ROIC) used for IRFPAs. The microbolometer as the sensing element absorbs infrared radiation which leads to a change of its temperature due to a very good thermal insulation. In conjunction with a high temperature coefficient of resistance (TCR) of the sensing material (typical vanadium oxide or amorphous silicon) this temperature change results in a change of the electrical resistance. During readout, electrical power is dissipated in the microbolometer, which increases the temperature continuously. The standard model for the electro-optical simulation of a microbolometer includes the radiation emitted by an observed blackbody, radiation emitted by the substrate, radiation emitted by the microbolometer itself to the surrounding, a heat loss through the legs which connect the microbolometer electrically and mechanically to the substrate, and the electrical power dissipation during readout of the microbolometer (Wood, 1997). The improved model presented in this paper takes a closer look on additional radiation effects in a real IR camera system, for example the radiation emitted by the casing and the lens. The proposed model will consider that some parts of the radiation that is reflected from the casing and the substrate is also absorbed by the microbolometer. Finally, the proposed model will include that some fraction of the radiation is transmitted through the microbolometer at first and then absorbed after the reflection at the surface of the substrate. Compared to the standard model temperature and resistance of the microbolometer can be modelled more realistically when these higher order effects are taken into account. A Verilog-A model for electronic circuit simulations is developed based on the improved thermal model of the microbolometer. Finally, a simulation result of a simple circuit is presented.
NASA Astrophysics Data System (ADS)
Han, Sang-Kug; Choi, Hoon; Moon, Kyo-Ho; Choi, Young-Seok; Jeong, Kyung-Deuk; Park, Kwang-Mook; Choi, Sie-Young
2012-04-01
We have developed the integrated amorphous silicon gate driver circuit using the model extraction technique of the inverted staggered and nonsymmetric amorphous silicon (a-Si) thin film transistor. The relation between capacitance characteristics of hydrogenated a-Si (a-Si:H) integrated transistors and the output signal of the gate driver circuit is analyzed using UTMOST IV ver. 1.6.4.R and SMARTSPICE ver. 3.19.15.C. The accuracy of the simulated gate output signal using voltage-controlled capacitance modeling is verified with measured data. The a-Si gate driver circuit using the proposed (TFT) model increased the accuracy of rising (95.3%) and falling (92%) time, compared to the conventional model. The suggested model extraction technique can be used for bottom gate and asymmetric TFT structures.
Magnetized anisotropic ghost dark energy cosmological model
NASA Astrophysics Data System (ADS)
Das, Kanika; Sultana, Tazmin
2015-06-01
We present in this paper a LRS Bianchi type I cosmological model with dark matter and anisotropic ghost dark energy in presence of magnetic field. We have solved the Einstein's field equations with a particular form of Hubble parameter. The physical and geometrical behaviors of the model are discussed. It is observed that the anisotropy of the universe and that of the ghost dark energy tends to zero at late times and the universe becomes spatially homogeneous, isotropic and flat. The coincidence parameter increases with time. We have also studied the statefinder parameters. The results obtained are in agreement with the recent days observations.
Trading speed and accuracy by coding time: a coupled-circuit cortical model.
Standage, Dominic; You, Hongzhi; Wang, Da-Hui; Dorris, Michael C
2013-04-01
Our actions take place in space and time, but despite the role of time in decision theory and the growing acknowledgement that the encoding of time is crucial to behaviour, few studies have considered the interactions between neural codes for objects in space and for elapsed time during perceptual decisions. The speed-accuracy trade-off (SAT) provides a window into spatiotemporal interactions. Our hypothesis is that temporal coding determines the rate at which spatial evidence is integrated, controlling the SAT by gain modulation. Here, we propose that local cortical circuits are inherently suited to the relevant spatial and temporal coding. In simulations of an interval estimation task, we use a generic local-circuit model to encode time by 'climbing' activity, seen in cortex during tasks with a timing requirement. The model is a network of simulated pyramidal cells and inhibitory interneurons, connected by conductance synapses. A simple learning rule enables the network to quickly produce new interval estimates, which show signature characteristics of estimates by experimental subjects. Analysis of network dynamics formally characterizes this generic, local-circuit timing mechanism. In simulations of a perceptual decision task, we couple two such networks. Network function is determined only by spatial selectivity and NMDA receptor conductance strength; all other parameters are identical. To trade speed and accuracy, the timing network simply learns longer or shorter intervals, driving the rate of downstream decision processing by spatially non-selective input, an established form of gain modulation. Like the timing network's interval estimates, decision times show signature characteristics of those by experimental subjects. Overall, we propose, demonstrate and analyse a generic mechanism for timing, a generic mechanism for modulation of decision processing by temporal codes, and we make predictions for experimental verification. PMID:23592967
Modeling and Results for Creating Oblique Fields in a Magnetic Flux Leakage Survey Tool
NASA Astrophysics Data System (ADS)
Simek, James C.
2010-02-01
Integrity management programs designed to maintain safe pipeline systems quite often will use survey results from In line inspection (ILI) tools in addition to data from other sources. Commonly referred to a "smart pigs," one of the most widely used types are those based upon the magnetic flux leakage technique, typically used to detect and quantify metal loss zones. The majority of pipelines surveyed to date have used tools with the magnetic field direction axially aligned with the length of the pipeline. In order to enable detection and quantification of extremely narrow metal loss features or certain types of weld zone anomalies, tools employing magnetic circuits directing the magnetic fields around the pipe circumference have been designed and are use in segments where these feature categories are a primary concern. Modeling and laboratory test data of metal loss features will be used to demonstrate the response of extremely narrow metal loss zones as the features are rotated relative to the induced field direction. Based upon these results, the basis for developing a magnetizer capable of creating fields oblique to either pipeline axis will be presented along with the magnetic field profile models of several configurations.
Multi-coil magnetic field modeling.
Juchem, Christoph; Green, Dan; de Graaf, Robin A
2013-11-01
The performance of multi-coil (MC) magnetic field modeling is compared to dedicated wire patterns for the generation of spherical harmonic (SH) shapes as these are the workhorse for spatial encoding and magnetic field homogenization in MR imaging and spectroscopy. To this end, an example 48 channel MC setup is analyzed and shown to be capable of generating all first through fourth order SH shapes over small and large regions-of-interest relevant for MR investigations. The MC efficiency for the generation of linear gradient fields shares the same order of magnitude with classic and state-of-the-art SH gradient coils. MC field modeling becomes progressively more efficient with the synthesis of more complex field shapes that require the combination of multiple SH terms. The possibility of a region-specific optimization of both magnetic field shapes and generation performance with the MC approach are discussed with emphasis on the possible trade-off between the field accuracy and generation efficiency. MC shimming has been shown previously to outperform current SH shimming. Along with the efficiency gains of MC shimming shown here, the MC concept has the potential to (1) replace conventional shim systems that are based on sets of dedicated SH coils and (2) allow optimal object-specific shim solutions similar to object-specific RF coils. PMID:24095841
Multi-coil magnetic field modeling
NASA Astrophysics Data System (ADS)
Juchem, Christoph; Green, Dan; de Graaf, Robin A.
2013-11-01
The performance of multi-coil (MC) magnetic field modeling is compared to dedicated wire patterns for the generation of spherical harmonic (SH) shapes as these are the workhorse for spatial encoding and magnetic field homogenization in MR imaging and spectroscopy. To this end, an example 48 channel MC setup is analyzed and shown to be capable of generating all first through fourth order SH shapes over small and large regions-of-interest relevant for MR investigations. The MC efficiency for the generation of linear gradient fields shares the same order of magnitude with classic and state-of-the-art SH gradient coils. MC field modeling becomes progressively more efficient with the synthesis of more complex field shapes that require the combination of multiple SH terms. The possibility of a region-specific optimization of both magnetic field shapes and generation performance with the MC approach are discussed with emphasis on the possible trade-off between the field accuracy and generation efficiency.
Multi-Coil Magnetic Field Modeling
Juchem, Christoph; Green, Dan; de Graaf, Robin A.
2013-01-01
The performance of multi-coil (MC) magnetic field modeling is compared to dedicated wire patterns for the generation of spherical harmonic (SH) shapes as these are the workhorse for spatial encoding and magnetic field homogenization in MR imaging and spectroscopy. To this end, an example 48 channel MC setup is analyzed and shown to be capable of generating all first through fourth order SH shapes over small and large regions-of-interest relevant for MR investigations. The MC efficiency for the generation of linear gradient fields shares the same order of magnitude with classic and state-of-the-art SH gradient coils. MC field modeling becomes progressively more efficient with the synthesis of more complex field shapes that require the combination of multiple SH terms. The possibility of a region-specific optimization of both magnetic field shapes and generation performance with the MC approach are discussed with emphasis on the possible trade-off between the field accuracy and generation efficiency. MC shimming has been shown previously to outperform current SH shimming. Along with the efficiency gains of MC shimming shown here, the MC concept has the potential to 1) replace conventional shim systems that are based on sets of dedicated SH coils and 2) allow optimal object-specific shim solutions similar to object-specific RF coils. PMID:24095841
A process/physics-based compact model for nonclassical CMOS device and circuit design
NASA Astrophysics Data System (ADS)
Fossum, J. G.; Ge, L.; Chiang, M.-H.; Trivedi, V. P.; Chowdhury, M. M.; Mathew, L.; Workman, G. O.; Nguyen, B.-Y.
2004-06-01
A process/physics-based compact model (UFDG) for nonclassical MOSFETs having ultra-thin Si bodies (UTB) is overviewed. The model, in essence, is a compact Poisson-Schrödinger solver, including accountings for short-channel effects, and is applicable to nanoscale fully depleted (FD) SOI MOSFETs as well as generic double-gate (DG) devices. The utility of UFDG in nonclassical CMOS device design, as well as circuit design, is stressed, and demonstrated by using it in Spice3 to design UTB MOSFETs and to project extremely scaled DG and FD/SOI CMOS performances. Also, calibration of UFDG to fabricated FinFETs yields new physical insights about these potentially viable nanoscale DG devices, and about model requirements for them.
A New Nonlinear Anisotropic Model for Soft Magnetic Materials
D. Lin; P. Zhou; Z. Badics; W. N. Fu; Q. M. Chen; Z. J. Cendes
2005-01-01
An accurate and efficient nonlinear anisotropic model for soft magnetic materials is developed. In this model, the cross effects of the magnetic field components in different principle directions are decoupled by introducing an equivalent magnitude of the magnetic field in each principle direction based on an anisotropic characterization of the energy density. Only B- H curves in the principal directions
A new nonlinear anisotropic model for soft magnetic materials
D. Lin; P. Zhou; Z. Badics; W. N. Fu; Q. M. Chen; Z. J. Cendes
2006-01-01
An accurate and efficient nonlinear anisotropic model for soft magnetic materials is developed. In this model, the cross effects of the magnetic field in the different principle directions are decoupled by introducing an equivalent magnetic field magnitude in each principle direction. This equivalence is based on an anisotropic characterization of the energy density. Only B-H curves in the principal directions
Problems in modeling reversible processes in soft magnetic materials
O. Benda; J. Bydzovský
1996-01-01
The reversible processes in soft magnetic materials (SMMs), in contrast with magnetic recording media, represent an important part of the magnetization process. One therefore looks for an adequate implementation of reversible processes in the Preisach model of SMMs. This paper aims to show that the disagreement among different authors about how to include reversible processes in the Preisach model in
Numerical Modeling of Ferrofluid Droplets in Magnetic Fields
Renardy, Yuriko
Numerical Modeling of Ferrofluid Droplets in Magnetic Fields S. Afkhami , Y. Renardy , M. Renardy viscous fluid and driven by a magnetic field are modeled numerically. The governing equations in the drop under non-uniform magnetic fields are simulated. Droplets exhibit shape changes along the applied
Model of Protein Kinase B for Cell Survival/Death and its Equivalent Bio Circuit
NASA Astrophysics Data System (ADS)
Jain, Shruti; Naik, Pradeep K.; Bhooshan, Sunil V.
2011-12-01
Signaling pathways have traditionally focused on delineating immediate upstream and down stream interactions, and then organizing these interactions into linear cascades that relay and regulate information from cell surface receptors to cellular effectors such as metabolic enzymes, channels or transcription factors. However, recent analyses of signaling pathways have revealed that cellular signals do not necessarily propagate in a linear fashion. Because of their size and complexity, these networks are often too complicated for the human mind to organize and analyze. AkT (protein kinase B) is a central signaling molecule in the phosphatidylinositol 3-kinase pathway that is frequently activated in human cancer. Here we provide an overview of recent findings, how AkT promotes cell survival by inhibiting apoptosis by phosphorylating and inactivating several targets, including forkhead transcription factors, and caspase-9. The ability of AkT to promote survival was dependent on and proportional to its kinase activity. We have made computational model for AkT, on the basis of that model we have made the truth tables, Boolean equations and than implement the equations using logic circuits and Bio-circuits showing cell survival and death.
Comparison of single particle and equivalent circuit analog models for a lithium-ion cell
NASA Astrophysics Data System (ADS)
Rahimian, Saeed Khaleghi; Rayman, Sean; White, Ralph E.
2011-10-01
The physics-based single particle (SP) model was compared to the semi-empirical equivalent circuit analog (ECA) model to predict the cell voltage under constant current charge and discharge for different sets of Li-ion cell data. The parameters of the models were estimated for each set of data using nonlinear least squares regression. In order to enhance the probability of finding the global optima, a combination of the trust region method with a genetic algorithm was applied to minimize the objective function (the sum of squared residuals). Several statistical quantities such as sum of the squared errors, adjusted R2, root mean squared error, confidence intervals of the parameters, and prediction bounds were included to compare the models. A significance test (t test) on the parameters and the analysis of the variances (F and ?2 tests) were also performed to discriminate between the goodness of the fit obtained from the two models. The statistical results indicate that the SP model superiorly predicts all sets of data compared to the ECA model, while the computation times of both models are on the same order of magnitude.
Modeling Skin Effect With Reduced Decoupled R-L Circuits S.Mei and Y. 1.Ismail
Ismail, Yehea
Modeling Skin Effect With Reduced Decoupled R-L Circuits S.Mei and Y. 1.Ismail Electrical-chip conductors such as clock and power distribution networks require accurately modeling skin effect. Furthermore, to incorporate skin effect in the existing generic simulation tools such as SPICE, simple frequency independent
Choi, Woo-Young
Avalanche Photodetectors Fabricated in Standard CMOS Process Myung-Jae Lee, Student Member, IEEE, Hyo model for CMOS- compatible avalanche photodetectors. The equivalent circuit model includes an inductive component for avalanche delay, a cur- rent source for photogenerated carriers, and several components
directed toward multi- walled CNT (MWCNT) interconnects, there is a lack of MWCNT modeling work. This paper presents, for the first time, a detailed investigation of MWCNT-based interconnect performance. A com- pact equivalent circuit model of MWCNTs is presented for the first time, and the performance of MWCNT
NASA Astrophysics Data System (ADS)
Banchuin, Rawid; Chipipop, Boonruk; Sirinaovakul, Boonchareon
In this research, the practical OTA-based inductors of all structures have been studied and their complete passive equivalent circuit models, where the effects of both parasitic elements and finite opened-loop bandwidth have been taken into account, also contain only the conventional standard linear elements i. e. the ordinary resistor, inductor and capacitor, without any infeasible high order element e. g. super inductor etc., have been proposed. The resulting models have been found to be excellently accurate, excellently straight forward, far superior to the previously proposed ones and completely realizable by the passive elements. Hence, the proposed passive equivalent circuit models have been found to be the convenience and versatile tools for the implementation of any analog and mixed signal processing circuits and systems.
Integration of MHD load models with circuit representations the Z generator.
Jennings, Christopher A.; Ampleford, David J.; Jones, Brent Manley; McBride, Ryan D.; Bailey, James E.; Jones, Michael C.; Gomez, Matthew Robert.; Cuneo, Michael Edward; Nakhleh, Charles; Stygar, William A.; Savage, Mark Edward; Wagoner, Timothy C.; Moore, James K.
2013-03-01
MHD models of imploding loads fielded on the Z accelerator are typically driven by reduced or simplified circuit representations of the generator. The performance of many of the imploding loads is critically dependent on the current and power delivered to them, so may be strongly influenced by the generators response to their implosion. Current losses diagnosed in the transmission lines approaching the load are further known to limit the energy delivery, while exhibiting some load dependence. Through comparing the convolute performance of a wide variety of short pulse Z loads we parameterize a convolute loss resistance applicable between different experiments. We incorporate this, and other current loss terms into a transmission line representation of the Z vacuum section. We then apply this model to study the current delivery to a wide variety of wire array and MagLif style liner loads.
A novel ECMO circuit using a SYNERGY circulite pump in a swine model.
Biscotti, Mauer; Singh, Gopal; Downey, Peter; Bacchetta, Matthew
2014-01-01
Extracorporeal membrane oxygenation (ECMO) is used in the management of refractory cardiopulmonary failure. With improvements in technology, patients can be transferred between hospitals, ambulated, and supported for extended periods of time while on ECMO. The SYNERGY CircuLite micropump is a blood pump that has been used as a ventricular assist device for partial support. In this study, we assessed the blood biocompatibility of the SYNERGY blood pump in conjunction with a Quadrox D oxygenator for use in a novel ECMO circuit in a swine model. This clinical design was used to demonstrate early feasibility of this pump system. Four pigs were placed on venovenous ECMO circuit, which consisted of a SYNERGY pump, Quadrox D oxygenator, and Cobe E Pack 3/8 inch tubing. All animals survived the 6 hour ECMO run without catastrophic biocompatibility issues. There was no statistically discernible change from baseline in hematologic parameters, including hemoglobin, plasma-free hemoglobin, total bilirubin, lactate dehydrogenase, D-dimer, fibrinogen, platelets, and P-selectin. We believe that this study serves as a proof of concept and basis for further studies using the SYNERGY pump as a component of ECMO systems. PMID:25000387
Analysis of each branch current of serial solar cells by using an equivalent circuit model
NASA Astrophysics Data System (ADS)
Yi, Shi-Guang; Zhang, Wan-Hui; Ai, Bin; Song, Jing-Wei; Shen, Hui
2014-02-01
In this paper, based on the equivalent single diode circuit model of the solar cell, an equivalent circuit diagram for two serial solar cells is drawn. Its equations of current and voltage are derived from Kirchhoff's current and voltage law. First, parameters are obtained from the I—V (current—voltage) curves for typical monocrystalline silicon solar cells (125 mm × 125 mm). Then, by regarding photo-generated current, shunt resistance, serial resistance of the first solar cell, and resistance load as the variables. The properties of shunt currents (Ish1 and Ish2), diode currents (ID1 and ID2), and load current (IL) for the whole two serial solar cells are numerically analyzed in these four cases for the first time, and the corresponding physical explanations are made. We find that these parameters have different influences on the internal currents of solar cells. Our results will provide a reference for developing higher efficiency solar cell module and contribute to the better understanding of the reason of efficiency loss of solar cell module.
Roberto Allub; Horacio Ceva; Blas R. Alascio
1984-01-01
We use Wilson's renormalization-group technique to calculate the magnetic susceptibility of an impurity model describing fluctuations between two magnetic configurations. We find a magnetic ground state and a divergent susceptibility at low temperatures. When the configuration with larger degeneracy is more stable than the other, the model can be reduced to a spin-1 Kondo model and its low-temperature behavior exhibits
Effects of rest time on discharge response and equivalent circuit model for a lead-acid battery
NASA Astrophysics Data System (ADS)
Devarakonda, Lalitha; Hu, Tingshu
2015-05-01
This work carries out a detailed investigation on the effects of rest time on the discharge response and the parameters of the Thevenin's equivalent circuit model for a lead acid battery. Traditional methods for battery modeling require a long rest time before a discharging test so that a steady state is reached for the open circuit voltage. In a recent work, we developed an algebraic method for parameter identification of circuit models for batteries by applying discharging tests after variable and possibly very short rest time. This new method opens a door to the understanding of the effects of rest time on battery behavior, which may be used for better simulation, analysis and design of battery powered systems for improved battery efficiency and state of health. As we used the new method to extract circuit parameters after different rest times, we observed some unexpected results on the relationship between the rest time and circuit parameters. The initial voltages on the capacitors can be negative and becomes more negative as the rest time is increased. We also observed that the time constants increase with rest time. Relationships between rest time and other parameters are also reported in this paper.
Exchange-coupled magnetic films as models for nonuniform soft magnetic materials
I. Bakonyi; E. Tóth-Kádár; P. Horváth; F. I. Tóth
1984-01-01
Magnetization reversal characteristics of exchange-coupled magnetic films obtained by alternately electrodepositing soft Ni-Fe and hard Ni-Co layers on a wire substrate were studied with the help of a critical switching curve tracer. It is considered that the variety of magnetic nehaviour observed in such systems may serve, in some cases, as a simple model for understanding magnetization processes in soft
STDP Installs in Winner-Take-All Circuits an Online Approximation to Hidden Markov Model Learning
Kappel, David; Nessler, Bernhard; Maass, Wolfgang
2014-01-01
In order to cross a street without being run over, we need to be able to extract very fast hidden causes of dynamically changing multi-modal sensory stimuli, and to predict their future evolution. We show here that a generic cortical microcircuit motif, pyramidal cells with lateral excitation and inhibition, provides the basis for this difficult but all-important information processing capability. This capability emerges in the presence of noise automatically through effects of STDP on connections between pyramidal cells in Winner-Take-All circuits with lateral excitation. In fact, one can show that these motifs endow cortical microcircuits with functional properties of a hidden Markov model, a generic model for solving such tasks through probabilistic inference. Whereas in engineering applications this model is adapted to specific tasks through offline learning, we show here that a major portion of the functionality of hidden Markov models arises already from online applications of STDP, without any supervision or rewards. We demonstrate the emergent computing capabilities of the model through several computer simulations. The full power of hidden Markov model learning can be attained through reward-gated STDP. This is due to the fact that these mechanisms enable a rejection sampling approximation to theoretically optimal learning. We investigate the possible performance gain that can be achieved with this more accurate learning method for an artificial grammar task. PMID:24675787
Constraining groundwater modeling with magnetic resonance soundings.
Boucher, Marie; Favreau, Guillaume; Nazoumou, Yahaya; Cappelaere, Bernard; Massuel, Sylvain; Legchenko, Anatoly
2012-01-01
Magnetic resonance sounding (MRS) is a noninvasive geophysical method that allows estimating the free water content and transmissivity of aquifers. In this article, the ability of MRS to improve the reliability of a numerical groundwater model is assessed. Thirty-five sites were investigated by MRS over a ?5000 km(2) domain of the sedimentary Continental Terminal aquifer in SW Niger. Time domain electromagnetic soundings were jointly carried out to estimate the aquifer thickness. A groundwater model was previously built for this section of the aquifer and forced by the outputs from a distributed surface hydrology model, to simulate the observed long-term (1992 to 2003) rise in the water table. Uncertainty analysis had shown that independent estimates of the free water content and transmissivity values of the aquifer would facilitate cross-evaluation of the surface-water and groundwater models. MRS results indicate ranges for permeability (K = 1 × 10(-5) to 3 × 10(-4) m/s) and for free water content (w = 5% to 23% m(3) /m(3) ) narrowed by two orders of magnitude (K) and by ?50% (w), respectively, compared to the ranges of permeability and specific yield values previously considered. These shorter parameter ranges result in a reduction in the model's equifinality (whereby multiple combinations of model's parameters are able to represent the same observed piezometric levels), allowing a better constrained estimate to be derived for net aquifer recharge (?22 mm/year). PMID:22150349
A new ferromagnetic hysteresis model for soft magnetic composite materials
NASA Astrophysics Data System (ADS)
Zidari?, Bogomir; Miljavec, Damijan
2011-01-01
A new ferromagnetic hysteresis model for soft magnetic composite materials based on their specific properties is presented. The model relies on definition of new anhysteretic magnetization based on the Cauchy-Lorentz distribution describing the maximum energy state of magnetic moments in material. Specific properties of soft magnetic composite materials (SMC) such as the presence of the bonding material, different sizes and shapes of the Fe particles, level of homogeneity of the Fe particles at the end of the SMC product treatment, and achieved overall material density during compression, are incorporated in both the anhysteretic differential magnetization susceptibility and the irreversible differential magnetization susceptibility. Together they form the total differential magnetization susceptibility that defines the new ferromagnetic hysteresis model. Genetic algorithms are used to determine the optimal values of the proposed model parameters. The simulated results show good agreement with the measured results.
NASA Astrophysics Data System (ADS)
Yang, Xiankun; Chen, Haoyuan; Cheng, Linan; Zheng, Xitao
2011-11-01
The circuit model was applied to predict the pin load distribution of composite multiple bolt-joint structure. The load, flexibility and deformation of the mechanics model were equivalent to the current, resistance and voltage of the circuit model, respectively. Based on the above assumption, it could be found that the Hooke's law and the deformation compatibility equation in the origin mechanics model transformed into the Ohm's law and the voltage balance equation in the new circuit model. This approach translated the complex model of composite multiple bolt-jointed into a simple circuit model which consisted of some series circuits and parallel circuits. The analysis of the new circuit model had formed n-1 independence voltage balance equations and a current balance equation, thus, the current and load of each bolt could be calculated. In the new model, power sources which were added as required in some branch circuits could also simulate the clearance or interference in the origin model. Compared with the result of the multiple bolt-joints composite laminate test, the new approach could make an excellent performance to estimate the load distribution.
NASA Astrophysics Data System (ADS)
Yang, Xiankun; Chen, Haoyuan; Cheng, Linan; Zheng, Xitao
2012-04-01
The circuit model was applied to predict the pin load distribution of composite multiple bolt-joint structure. The load, flexibility and deformation of the mechanics model were equivalent to the current, resistance and voltage of the circuit model, respectively. Based on the above assumption, it could be found that the Hooke's law and the deformation compatibility equation in the origin mechanics model transformed into the Ohm's law and the voltage balance equation in the new circuit model. This approach translated the complex model of composite multiple bolt-jointed into a simple circuit model which consisted of some series circuits and parallel circuits. The analysis of the new circuit model had formed n-1 independence voltage balance equations and a current balance equation, thus, the current and load of each bolt could be calculated. In the new model, power sources which were added as required in some branch circuits could also simulate the clearance or interference in the origin model. Compared with the result of the multiple bolt-joints composite laminate test, the new approach could make an excellent performance to estimate the load distribution.
Brittle superconducting magnets: an equivilent strain model
Barzi, E.; /Fermilab; Danuso, M.
2010-08-01
To exceed fields of 10 T in accelerator magnets, brittle superconductors like A15 Nb{sub 3}Sn and Nb{sub 3}Al or ceramic High Temperature Superconductors have to be used. For such brittle superconductors it is not their maximum tensile yield stress that limits their structural resistance as much as strain values that provoke deformations in their delicate lattice, which in turn affect their superconducting properties. Work on the sensitivity of Nb{sub 3}Sn cables to strain has been conducted in a number of stress states, including uniaxial and multi-axial, producing usually different results. This has made the need of a constituent design criterion imperative for magnet builders. In conventional structural problems an equivalent stress model is typically used to verify mechanical soundness. In the superconducting community a simple scalar equivalent strain to be used in place of an equivalent stress would be an extremely useful tool. As is well known in fundamental mechanics, there is not one single way to reduce a multiaxial strain state as represented by a 2nd order tensor to a scalar. The conceptual experiment proposed here will help determine the best scalar representation to use in the identification of an equivalent strain model.
Magnetic Actuator Modelling for Rotating Machinery Analysis
NASA Astrophysics Data System (ADS)
Mendes, Ricardo Ugliara; de Castro, Hélio Fiori; Cavalca, Kátia Lucchesi; Ferreira, Luiz Otávio Saraiva
Rotating machines have a wide range of application such as airplanes, factories, laboratories and power plants. Lately, with computer aid design, shafts finite element models including bearings, discs, seals and couplings have been developed, allowing the prediction of the machine behavior. In order to keep confidence during operation, it is necessary to monitor these systems, trying to predict future failures. One of the most applied technique for this purpose is the modal analysis. It consists of applying a perturbation force into the system and then to measure its response. However, there is a difficulty that brings limitations to the excitation of systems with rotating shafts when using impact hammers or shakers, once due to friction, undesired tangential forces and noise can be present in the measurements. Therefore, the study of a non-contact technique of external excitation becomes of high interest. In this sense, the present work deals with the study and development of a finite element model for rotating machines using a magnetic actuator as an external excitation source. This work also brings numerical simulations where the magnetic actuator was used to obtain the frequency response function of the rotating system.
NASA Astrophysics Data System (ADS)
Quan, Tingwei; Li, Jing; Zhou, Hang; Li, Shiwei; Zheng, Ting; Yang, Zhongqing; Luo, Qingming; Gong, Hui; Zeng, Shaoqun
2014-05-01
Mapping the neuronal circuits is essential to understand brain function. Recent technological advancements have made it possible to acquire the brain atlas at single cell resolution. Digital reconstruction of the neural circuits down to this level across the whole brain would significantly facilitate brain studies. However, automatic reconstruction of the dense neural connections from microscopic image still remains a challenge. Here we developed a spherical-coordinate based variational model to reconstruct the shape of the cell body i.e. soma, as one of the procedures for this purpose. When intuitively processing the volumetric images in the spherical coordinate system, the reconstruction of somas with variational model is no longer sensitive to the interference of the complicated neuronal morphology, and could automatically and robustly achieve accurate soma shape regardless of the dense spatial distribution, and diversity in cell size, and morphology. We believe this method would speed drawing the neural circuits and boost brain studies.
NASA Astrophysics Data System (ADS)
Chu, J.; Chang, X. L.; Zhao, M.; Man, M. H.; Yuan, L.; Wei, M.
2013-03-01
With the continuous improvement of circuit integration and working clock frequency in the electronic system, it is increasingly easy for the system to be affected by electromagnetic waves, and electromagnetic susceptibility and vulnerability become more severe. However, living beings in nature have shown extraordinary compatibility, immunity and adaptability to the electromagnetism at the same time. In addition, the ion channel on the neuron cytomembrane is a typical representation of "bioelectrical immunity". So the Hodgkin-Huxley circuit model with one capacitor in parallel with some power supplies and resistors was adopted to simulate the ion channel on the neuron cytomembrane. Through analysis, the circuit model can be used to simulate some electrical characteristics of biological neuron cells, and then acquire a certain level of anti-electromagnetic interference ability. This method will be useful for improving the reliability, compatibility and anti-interference capability of the electronic system in the complicated electromagnetic environment.
Quan, Tingwei; Li, Jing; Zhou, Hang; Li, Shiwei; Zheng, Ting; Yang, Zhongqing; Luo, Qingming; Gong, Hui; Zeng, Shaoqun
2014-01-01
Mapping the neuronal circuits is essential to understand brain function. Recent technological advancements have made it possible to acquire the brain atlas at single cell resolution. Digital reconstruction of the neural circuits down to this level across the whole brain would significantly facilitate brain studies. However, automatic reconstruction of the dense neural connections from microscopic image still remains a challenge. Here we developed a spherical-coordinate based variational model to reconstruct the shape of the cell body i.e. soma, as one of the procedures for this purpose. When intuitively processing the volumetric images in the spherical coordinate system, the reconstruction of somas with variational model is no longer sensitive to the interference of the complicated neuronal morphology, and could automatically and robustly achieve accurate soma shape regardless of the dense spatial distribution, and diversity in cell size, and morphology. We believe this method would speed drawing the neural circuits and boost brain studies. PMID:24829141
A Systematic Approach to Modeling Impedances and Current Distribution in Planar Magnetics
Chen, Minjie
Planar magnetic components using printed-circuit-board windings are attractive due to their high repeatability, good thermal performance and usefulness for realizing intricate winding patterns. To enable higher system ...
Development of models of magnetic films on a liquid substrate
Taktarov, N.G.
1985-07-01
The authors present new results of simple experiments conducted with films of magnetic surface-active materials (SAM) deposited on the surface of water. They use magnetic liquid with the following composition: kerosene, oleic acid, magnetite. They conclude that in constructing models of magnetic films it is necessary to take account of their mass exchange with volummetric masses.
An ionospheric conductance model based on ground magnetic disturbance data
B.-H. Ahn; A. D. Richmond; Y. Kamide; H. W. Kroehl; B. A. Emery; O. de la Beaujardiére; S.-I. Akasofu
1998-01-01
An attempt is made to construct an improved ionospheric conductance model employing ground magnetic disturbance data as input. For each of the different regions in the auroral electrojets specified by different combinations of horizontal (DeltaH) and vertical (DeltaZ) magnetic perturbations, as well as by magnetic local time (MLT), an empirical relationship is obtained between the ionospheric conductance deduced from Chatanika
The Inductrack: a simpler approach to magnetic levitation
Richard F. Post; D. D. Ryutov
2000-01-01
Arising out of research at the Lawrence Livermore National Laboratory on passive magnetic bearings, a new magnetic levitation system, the Inductrack, has been developed and tested at model scale. The system employs special arrays of permanent magnets (Halbach arrays) on the moving car. The magnetic field from the arrays induces repelling currents in a close-packed array of shorted circuits in
Simulation of double layers in a model auroral circuit with nonlinear impedance
NASA Technical Reports Server (NTRS)
Smith, R. A.
1986-01-01
A reduced circuit description of the U-shaped potential structure of a discrete auroral arc, consisting of the flank transmission line plus parallel-electric-field region, is used to provide the boundary condition for one-dimensional simulations of the double-layer evolution. The model yields asymptotic scalings of the double-layer potential, as a function of an anomalous transport coefficient alpha and of the perpendicular length scale l(a) of the arc. The arc potential phi(DL) scales approximately linearly with alpha, and for alpha fixed phi (DL) about l(a) to the z power. Using parameters appropriate to the auroral zone acceleration region, potentials of phi (DPL) 10 kV scale to projected ionospheric dimensions of about 1 km, with power flows of the order of magnitude of substorm dissipation rates.
Modelling and analysis of local field potentials for studying the function of cortical circuits.
Einevoll, Gaute T; Kayser, Christoph; Logothetis, Nikos K; Panzeri, Stefano
2013-11-01
The past decade has witnessed a renewed interest in cortical local field potentials (LFPs)--that is, extracellularly recorded potentials with frequencies of up to ~500 Hz. This is due to both the advent of multielectrodes, which has enabled recording of LFPs at tens to hundreds of sites simultaneously, and the insight that LFPs offer a unique window into key integrative synaptic processes in cortical populations. However, owing to its numerous potential neural sources, the LFP is more difficult to interpret than are spikes. Careful mathematical modelling and analysis are needed to take full advantage of the opportunities that this signal offers in understanding signal processing in cortical circuits and, ultimately, the neural basis of perception and cognition. PMID:24135696
Equivalent circuit modeling and vibrometry measurements of the Nigerian-origin Udu Utar drum.
Anderson, Brian E; Hilton, C Beau; Giorgini, Frank
2013-03-01
The Udu drum, sometimes called the water pot drum, is a traditional Nigerian instrument. Musicians who play the Udu exploit its aerophone and idiophone resonances. This paper will discuss an electrical equivalent circuit model for the Udu Utar, a modern innovation of the traditional Udu, to predict the low frequency aerophone resonances and will also present scanning laser vibrometer measurements to determine the mode shapes of the dominant idiophone resonances. These analyses not only provide an understanding of the unique sound of the Udu instrument but may also be used by instrument designers to create instruments with resonance frequencies at traditional musical intervals for the various tones produced and to create musical harmonic ratios. The information, specifically the laser vibrometry measurements, may also be useful to musicians in knowing the best places to strike the Udu to excite musical tones. PMID:23464041
Contactless position sensor using magnetic saturation
Bertrand Legrand; Yves Dordet; Jean-Yves Voyant; Jean-Paul Yonnet
2003-01-01
This paper describes different structures for the realization of a contactless position sensor when restricting to a magnet as the target and an inductance as the sensing element. The principle of measurement is the local saturation of an inductance core by a magnet. A sensor model is explained using Maxwell equations on the magnetic circuit. Some response curves are also
Chung Hang John Poh; Swapan K. Bhattacharya; Jason Ferguson; John D. Cressler; John Papapolymerou
2010-01-01
A methodology for extracting an accurate, lumped element, equivalent circuit model for an interlayer via in a 3-D packaging scheme is presented. The model of a single via is extracted based upon the EM simulation of a test structure in which the via is landed at an internal capacitance layer within the multi-layer Liquid Crystal Polymer (LCP) or Printed Circuit
Francesco Ferranti; Giulio Antonini; Tom Dhaene; Luc Knockaert
2010-01-01
The decrease of IC feature size and the increase of operating frequencies require 3-D electromagnetic methods, such as the partial element equivalent circuit (PEEC) method, for the analysis and design of high-speed circuits. Very large systems of equations are often produced by 3-D electromagnetic methods. During the circuit synthesis of large-scale digital or analog applications, it is important to predict
Josep Carmona; Jordi Cortadella; Michael Kishinevsky; Alexander Taubin
2009-01-01
Elasticity in circuits and systems provides tolerance to variations in computation and communication delays. This paper presents a comprehensive overview of elastic circuits for those designers who are mainly familiar with synchronous design. Elasticity can be implemented both synchronously and asynchronously, although it was traditionally more often associated with asynchronous circuits. This paper shows that synchronous and asynchronous elastic circuits
NSDL National Science Digital Library
University of Wisconsin Extension
2002-01-01
In this activity about electricity, learners identify closed and open circuits. First, learners examine and label diagrams of open and closed circuits. Then, learners build each of the circuits shown in the diagrams using electrical supplies. Throughout the activity, learners predict and then test if the light bulbs will turn on based on the circuit type.
M. Saitou
2009-01-01
We have investigated a deposited mass ratio represented by the ratio between the actual deposited mass and the deposited mass expected from Faraday's law in nickel pulse electrodeposition. The deposited mass ratio decays exponentially with the pulse current frequency and approaches asymptotically to a constant value at a high frequency. An analytical solution for an electric circuit model equivalent to
Christian Kral; Anton Haumer; Matthias Haigis; Hermann Lang; HansjÖrg Kapeller
2009-01-01
For a totally enclosed fan-cooled induction machine, two methods of numerical analysis are compared with measurements. The first numerical method is based on computational fluid dynamics (CFDs) and the second one uses a thermal equivalent circuit (TEC). For the analysis based on CFD, a 3-D induction machine including housing is modeled. The numeric solution of the flow equations is determined
NASA Astrophysics Data System (ADS)
Seaman, Aden; Dao, Thanh-Son; McPhee, John
2014-06-01
In this paper, we survey two kinds of mathematics-based battery models intended for use in hybrid and electric vehicle simulation. The first is circuit-based, which is founded upon the electrical behaviour of the battery, and abstracts away the electrochemistry into equivalent electrical components. The second is chemistry-based, which is founded upon the electrochemical equations of the battery chemistry.
E. Suhir
2010-01-01
Based on the developed analytical (“mathematical”) stress model, we evaluate the dynamic response of a “flexible-and-heavy” square simply supported printed circuit board (PCB) to an impact load applied to its support contour during drop tests. The analysis is restricted to the first mode of vibrations and is carried out in application to a PCB structure employed in an advanced accelerated
Magnetic models of saturated interior permanent magnet motors based on finite element analysis
Nicola Bianchi; Sihrerio Bolognani
1998-01-01
This paper deals with the magnetic model of an interior permanent magnet synchronous motor, whose parameters are computed using finite element analysis. As known, in unsaturated conditions the motor inductive parameters and flux linkage call be univocally determined. Conversely, under saturated operation, different choices may be adopted to define them. Various models are examined, with the purpose to individuate the
NASA Technical Reports Server (NTRS)
Perez, Reinaldo J.
2011-01-01
Single Event Transients in analog and digital electronics from space generated high energetic nuclear particles can disrupt either temporarily and sometimes permanently the functionality and performance of electronics in space vehicles. This work first provides some insights into the modeling of SET in electronic circuits that can be used in SPICE-like simulators. The work is then directed to present methodologies, one of which was developed by this author, for the assessment of SET at different levels of integration in electronics, from the circuit level to the subsystem level.
NASA Astrophysics Data System (ADS)
Pérez-Benítez, J. A.; Espina-Hernández, J. H.; Martínez-Ortiz, P.; Chávez-González, A. F.; de la Rosa, J. M.
2013-12-01
A microscopic model of magnetic Barkhausen noise (MBN) in carbon steel is proposed. The model uses the quasi-static magnetic formulation of Maxwell equations for electromagnetic fields combined with a microscopic model of the magnetic Barkhausen noise, and its equations are solved by means of finite difference formulation. The simulated MBN signal obtained presents high similarities to the measured MBN signal. Using this model, the influences of the uniformity and waveform profile of the excitation magnetic field on the envelope of the MBN signal were studied. The results show that the lack of uniformity of the excitation magnetic field increases the amplitude of the MBN envelope at the right of its main peak, and the waveform profile influences the shape of the MBN envelope. The proposed model can be used as a tool for studying the influence of several excitation parameters on the Barkhausen Noise in order to improve this technique.
Power-Invariant Magnetic System Modeling
Gonzalez Dominguez, Guadalupe Giselle
2012-10-19
Hans Cristian Oersted discovered that an electric current produced a magnetic field in its neighborhood. The nature of this phenomenon was fully explored by André Ampère and Wilhelm Eduard Weber. They showed that a current loop was magnetically...
Programmable impulse neural circuits
Jack L. Meador; Angus Wu; Clint Cole; Novat Nintunze; Pichet Chintrakulchai
1991-01-01
A description is given of CMOS electronic circuits which emulate natural neurons at a more detailed level than that typically used by artificial neural network models. A pulse-firing circuit which realizes general short-term neuron dynamics is discussed. Both fixed and programmable synapse circuits for realizing long-term dynamics are also described. Together, these establish the basic structures required for the implementation
2011-01-01
Thermally assisted spin transfer torque [TAS + STT] is a new switching approach for magnetic tunnel junction [MTJ] nanopillars that represents the best trade-off between data reliability, power efficiency and density. In this paper, we present a compact model for MTJ switched by this approach, which integrates a number of physical models such as temperature evaluation and STT dynamic switching models. Many experimental parameters are included directly to improve the simulation accuracy. It is programmed in the Verilog-A language and compatible with the standard IC CAD tools, providing an easy parameter configuration interface and allowing high-speed co-simulation of hybrid MTJ/CMOS circuits. PMID:21711868
Zhao, Weisheng; Duval, Julien; Klein, Jacques-Olivier; Chappert, Claude
2011-01-01
Thermally assisted spin transfer torque [TAS + STT] is a new switching approach for magnetic tunnel junction [MTJ] nanopillars that represents the best trade-off between data reliability, power efficiency and density. In this paper, we present a compact model for MTJ switched by this approach, which integrates a number of physical models such as temperature evaluation and STT dynamic switching models. Many experimental parameters are included directly to improve the simulation accuracy. It is programmed in the Verilog-A language and compatible with the standard IC CAD tools, providing an easy parameter configuration interface and allowing high-speed co-simulation of hybrid MTJ/CMOS circuits. PMID:21711868
NASA Astrophysics Data System (ADS)
Zhao, Weisheng; Duval, Julien; Klein, Jacques-Olivier; Chappert, Claude
2011-12-01
Thermally assisted spin transfer torque [TAS + STT] is a new switching approach for magnetic tunnel junction [MTJ] nanopillars that represents the best trade-off between data reliability, power efficiency and density. In this paper, we present a compact model for MTJ switched by this approach, which integrates a number of physical models such as temperature evaluation and STT dynamic switching models. Many experimental parameters are included directly to improve the simulation accuracy. It is programmed in the Verilog-A language and compatible with the standard IC CAD tools, providing an easy parameter configuration interface and allowing high-speed co-simulation of hybrid MTJ/CMOS circuits.
Cardiovascular Magnetic Resonance Imaging in Experimental Models
Price, Anthony N.; Cheung, King K.; Cleary, Jon O; Campbell, Adrienne E; Riegler, Johannes; Lythgoe, Mark F
2010-01-01
Cardiovascular magnetic resonance (CMR) imaging is the modality of choice for clinical studies of the heart and vasculature, offering detailed images of both structure and function with high temporal resolution. Small animals are increasingly used for genetic and translational research, in conjunction with models of common pathologies such as myocardial infarction. In all cases, effective methods for characterising a wide range of functional and anatomical parameters are crucial for robust studies. CMR is the gold-standard for the non-invasive examination of these models, although physiological differences, such as rapid heart rate, make this a greater challenge than conventional clinical imaging. However, with the help of specialised magnetic resonance (MR) systems, novel gating strategies and optimised pulse sequences, high-quality images can be obtained in these animals despite their small size. In this review, we provide an overview of the principal CMR techniques for small animals for example cine, angiography and perfusion imaging, which can provide measures such as ejection fraction, vessel anatomy and local blood flow, respectively. In combination with MR contrast agents, regional dysfunction in the heart can also be identified and assessed. We also discuss optimal methods for analysing CMR data, particularly the use of semi-automated tools for parameter measurement to reduce analysis time. Finally, we describe current and emerging methods for imaging the developing heart, aiding characterisation of congenital cardiovascular defects. Advanced small animal CMR now offers an unparalleled range of cardiovascular assessments. Employing these methods should allow new insights into the structural, functional and molecular basis of the cardiovascular system. PMID:21331311
Contactless magnetic leadscrew: modeling and load determination
Zhiming Ji; Timothy N. Chang; Michael Shimanovich; Reggie J. Caudill
2000-01-01
Magnetically coupled leadscrews with aerostatic suspension provide superior precision for motion control. The paper focuses on load capacity determination for such drives. Boundary conditions for airgap magnetic field are derived and used to solve the corresponding Laplace equation. The result is then used to calculate airgap permeance and obtain the operating point of the magnet. Finally relationships between load and
Gao, Yujie; Li, Xingang; Ding, Hui
2015-08-01
A layer model was established to elucidate the mechanism of zinc removal from the metallic mixture of waste printed circuit boards by vacuum distillation. The removal process was optimized by response surface methodology, and the optimum operating conditions were the chamber pressure of 0.1Pa, heating temperature of 923K, heating time of 60.0min, particle size of 70 mesh (0.212mm) and initial mass of 5.25g. Evaporation efficiency of zinc, the response variable, was 99.79%, which indicates that the zinc can be efficiently removed. Based on the experimental results, a mathematical model, which bears on layer structure, evaporation, mass transfer and condensation, interprets the mechanism of the variable effects. Especially, in order to reveal blocking effect on the zinc removal, the Blake-Kozeny-Burke-Plummer equation was introduced into the mass transfer process. The layer model can be applied to a wider range of metal removal by vacuum distillation. PMID:25957936
Anomalous transport in discrete arcs and simulation of double layers in a model auroral circuit
NASA Technical Reports Server (NTRS)
Smith, Robert A.
1987-01-01
The evolution and long-time stability of a double layer in a discrete auroral arc requires that the parallel current in the arc, which may be considered uniform at the source, be diverted within the arc to charge the flanks of the U-shaped double-layer potential structure. A simple model is presented in which this current re-distribution is effected by anomalous transport based on electrostatic lower hybrid waves driven by the flank structure itself. This process provides the limiting constraint on the double-layer potential. The flank charging may be represented as that of a nonlinear transmission. A simplified model circuit, in which the transmission line is represented by a nonlinear impedance in parallel with a variable resistor, is incorporated in a 1-d simulation model to give the current density at the DL boundaries. Results are presented for the scaling of the DL potential as a function of the width of the arc and the saturation efficiency of the lower hybrid instability mechanism.
Anomalous transport in discrete arcs and simulation of double layers in a model auroral circuit
NASA Technical Reports Server (NTRS)
Smith, Robert A.
1987-01-01
The evolution and long-time stability of a double layer (DL) in a discrete auroral arc requires that the parallel current in the arc, which may be considered uniform at the source, be diverted within the arc to charge the flanks of the U-shaped double layer potential structure. A simple model is presented in which this current redistribution is effected by anomalous transport based on electrostatic lower hybrid waves driven by the flank structure itself. This process provides the limiting constraint on the double layer potential. The flank charging may be represented as that of a nonlinear transmission line. A simplified model circuit, in which the transmission line is represented by a nonlinear impedance in parallel with a variable resistor, is incorporated in a one-dimensional simulation model to give the current density at the DL boundaries. Results are presented for the scaling of the DL potential as a function of the width of the arc and the saturation efficiency of the lower hybrid instability mechanism.
A complete circuit breaker model for calculating very fast transient voltages
Philipp Simka
2010-01-01
Various studies have been carried out to determine the origin, the development and the effects of very fast transients (VFT) in GIS-Busbars. To date little knowledge exists on how VFT propagate through a high voltage circuit breaker, when the interrupter itself is the source of the VFT. For the development of circuit breakers it is important to know if these
Envelope Simulation by SPICE Compatible Models of Electric Circuits Driven by Modulated Signals
of electric circuits driven by modulated signals. The circuits are based on a novel complex phasor domain to the presence of the high frequency component. The method proposed in [5] is based on a phasor transformation Freq 3RZHU FM input signal 9lamp , lamp #12;2 In this study we developed a complex phasor
YI, YM; Hu, Chia-Ren.
1992-01-01
circuits containing 2 X 2 X 2, 4 X 4 X 4, and 6 X 6 X 6 cubes. For the last two cases, the study reported here is limited to the vicinity of one major peak of T(c)(H) only, in order to limit the total computing time. However, by going up to 6 X 6 X 6 cubes...
Two Models of Magnetic Support for Photoevaporated Molecular Clouds
D. D. Ryutov; J. O. Kane; A. Mizuta; M. W. Pound; B. A. Remington
2005-01-01
The thermal pressure inside molecular clouds is insufficient for maintaining the pressure balance at an ablation front at the cloud surface illuminated by nearby UV stars. Most probably, the required stiffness is provided by the magnetic pressure. After surveying existing models of this type, we concentrate on two of them: the model of a quasi-homogeneous magnetic field and the recently
Numerical modelling and analysis of a room temperature magnetic
results of both the behavior and the performance of the experimental AMR shows that the developed modelNumerical modelling and analysis of a room temperature magnetic refrigeration system Thomas Frank and analysis of a room temperature magnetic refrigeration system Department: Fuel Cells and Solid State
Implementing a Magnetic Charge Topology Model for Solar Active Regions
Longcope, Dana
, as well as uncorrelated noise. We determine the reliability of our method and estimate the uncertainties test this prediction. Magnetic charge topology (MCT) models assume that the photospheric magnetic field MCT models to observations, photospheric fields must be somehow represented as a set of distinct
Advanced optical position sensors for magnetically suspended wind tunnel models
S. Lafleur
1985-01-01
A major concern to aerodynamicists has been the corruption of wind tunnel test data by model support structures, such as stings or struts. A technique for magnetically suspending wind tunnel models was considered by Tournier and Laurenceau (1957) in order to overcome this problem. This technique is now implemented with the aid of a Large Magnetic Suspension and Balance System
Recycler model magnet test on temperature compensation for strontium ferrite
Yamada, R.; Foster, W.; Ostiguy, F. [Fermi National Accelerator Lab., Batavia, IL (United States); Wake, M. [KEK (Japan)
1995-10-01
The Recycler ring magnet will be made of Strontium ferrite permanent magnets. A strontium ferrite permanent magnet without compensation has a temperature coefficient of -0.2 % in dB/dT. To compensate this effect, we are utilizing 30 % Ni 70 % Fe alloy, a temperature compensation ferromagnetic material with a low Curie point. To search for optimum commercially available material and optimum condition, we made a couple of simple model magnets, and tested with several different compensating material. The test results are reported and its optimal conditions are shown. Several different configurations were tested including a possible 2 kG magnet configuration.
A stochastic model of the galactic magnetic field
NASA Technical Reports Server (NTRS)
Kaiser, T. B.
1972-01-01
Existing stochastic models of the galactic magnetic field are considered and found to suffer certain defects. A new model is proposed which overcomes faults of the previous theories while retaining their strengths.
A. Rissons; J. Perchoux; J.-C. Mollier
2003-01-01
A circuit model of a vertical-cavity surface-emitting laser (VCSEL) array and its experimental validation are presented in this paper. This model describes all optoelectronic phenomena including relative intensity noise (RIN) and electrical crosstalk.
NASA Technical Reports Server (NTRS)
Pickett, H. M.; Farhoomand, J.; Chiou, A. E.
1984-01-01
Inductive mesh transmission has been measured for the two major polarizations as a function of incidence angle. The experimental data agree well with Chen's (1970) waveguide theory in the thin mesh limit. As an aid in making more rapid predictions of mesh properties, Chen's theory is used to derive an empirical lumped circuit model. This model matches the theory and experiment to one percent over critical areas of transmission.
New method of modeling electronic circuits coupled with 3D electromagnetic finite element models
J. R. Brauer; B. E. MacNeal; L. A. Larkin; V. D. Overbye
1991-01-01
New zero-dimensional or scalar electromagnetic finite elements, that have the time integral of electric scalar potential as their nodal variable are presented. There are three zero-dimensional element types, representing resistors, capacitors, and inductors. These elements can be easily combined with two- or three-dimensional elements, with three components of magnetic vector potential and the time integral of electric scalar potential as
Rabi model as a quantum coherent heat engine: From quantum biology to superconducting circuits
Ferdi Altintas; Ali Ü. C. Hardal; Özgür E. Müstecapl?o?lu
2015-02-18
We propose a multilevel quantum heat engine with a working medium described by a generalized Rabi model which consists of a two-level system coupled to a single mode bosonic field. The model is constructed to be a continuum limit of a quantum biological description of light harvesting complexes so that it can amplify quantum coherence by a mechanism which is a quantum analog of classical Huygen's clocks. The engine operates in quantum Otto cycle where the working medium is coupled to classical heat baths in the isochoric processes of the four stroke cycle; while either the coupling strength or the resonance frequency is changed in the adiabatic stages. We found that such an engine can produce work with an efficiency close to Carnot bound when it operates at low temperatures and in the ultrastrong coupling regime. Interplay of quantum coherence and quantum correlations on the engine performance is discussed in terms of second order coherence, quantum mutual information and logarithmic negativity of entanglement. We point out that the proposed quantum Otto engine can be implemented experimentally with the modern circuit quantum electrodynamic systems where flux qubits can be coupled ultrastrongly to superconducting transmission line resonators.
Kim, Young-Do; Lee, Hyo-Chang; Chung, Chin-Wook [Department of Electrical Engineering, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of)] [Department of Electrical Engineering, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of)
2013-09-15
Correlations between the external discharge parameters (the driving frequency ? and the chamber dimension R) and plasma characteristics (the skin depth ? and the electron-neutral collision frequency ?{sub m}) are studied using the transformer circuit model [R. B. Piejak et al., Plasma Sources Sci. Technol. 1, 179 (1992)] when the absorbed power is maximized in an inductively coupled plasma. From the analysis of the transformer circuit model, the maximum power transfer conditions, which depend on the external discharge parameters and the internal plasma characteristics, were obtained. It was found that a maximum power transfer occurs when ??0.38R for the discharge condition at which ?{sub m}/??1, while it occurs when ???(2)?(?/?{sub m})R for the discharge condition at which ?{sub m}/??1. The results of this circuit analysis are consistent with the stable last inductive mode region of an inductive-to-capacitive mode transition [Lee and Chung, Phys. Plasmas 13, 063510 (2006)], which was theoretically derived from Maxwell's equations. Our results were also in agreement with the experimental results. From this work, we demonstrate that a simple circuit analysis can be applied to explain complex physical phenomena to a certain extent.
Z. Q. Zhu; D. Howe
1993-01-01
For pt.II see ibid., vol.29, no.1, p.136-142 (1993). A method for modeling the effect of stator slotting on the magnetic field distribution in the airgap\\/magnet region of a radial-field brushless permanent-magnet DC motor equipped with a surface-mounted magnet rotor is presented to allow the analytical prediction of the open-circuit, armature-reaction, and consultant magnetic field distribution under any specified load condition.
Fernandez, Thomas
Double-Strength CAFFEINE: Fast Template-Free Symbolic Modeling of Analog Circuits via Implicit-MICAS Kasteelpark Arenberg 10 B-3001 Leuven, Belgium Abstract CAFFEINE, introduced previously, automatically of analog circuits, CAFFEINE was shown to have the best predictive ability from among 10 regression
Hummos, Ali; Franklin, Charles C; Nair, Satish S
2014-12-01
Acetylcholine regulates memory encoding and retrieval by inducing the hippocampus to switch between pattern separation and pattern completion modes. However, both processes can introduce significant variations in the level of network activity and potentially cause a seizure-like spread of excitation. Thus, mechanisms that keep network excitation within certain bounds are necessary to prevent such instability. We developed a biologically realistic computational model of the hippocampus to investigate potential intrinsic mechanisms that might stabilize the network dynamics during encoding and retrieval. The model was developed by matching experimental data, including neuronal behavior, synaptic current dynamics, network spatial connectivity patterns, and short-term synaptic plasticity. Furthermore, it was constrained to perform pattern completion and separation under the effects of acetylcholine. The model was then used to investigate the role of short-term synaptic depression at the recurrent synapses in CA3, and inhibition by basket cell (BC) interneurons and oriens lacunosum-moleculare (OLM) interneurons in stabilizing these processes. Results showed that when CA3 was considered in isolation, inhibition solely by BCs was not sufficient to control instability. However, both inhibition by OLM cells and short-term depression at the recurrent CA3 connections stabilized the network activity. In the larger network including the dentate gyrus, the model suggested that OLM inhibition could control the network during high cholinergic levels while depressing synapses at the recurrent CA3 connections were important during low cholinergic states. Our results demonstrate that short-term plasticity is a critical property of the network that enhances its robustness. Furthermore, simulations suggested that the low and high cholinergic states can each produce runaway excitation through unique mechanisms and different pathologies. Future studies aimed at elucidating the circuit mechanisms of epilepsy could benefit from considering the two modulatory states separately. PMID:24978936
Twelve-state Potts model in a magnetic field
NASA Astrophysics Data System (ADS)
Kassan-Ogly, F. A.; Filippov, B. N.; Proshkin, A. I.; Zarubin, A. V.
2015-02-01
In this work, we have obtained an exact solution to the one-dimensional modified 12-state Potts model using the Kramers-Wannier transfer matrix with allowance for the exchange interaction between nearest neighbors in an external magnetic field. Analytical expressions have been derived for the heat capacity, magnetization, magnetic susceptibility, magnetic entropy, and magnetocaloric effect as functions of temperature, magnitude and sign of exchange interaction, and the magnitude and direction of the magnetic field. The behavior of all of these parameters has been investigated in detail using numerical methods. The possibility of applying the results obtained to explain the observed magnetic properties of real cubic magnets with a NaCl structure and easy axes oriented along the [110] crystallographic directions has been discussed.
Modeling surface magnetic fields in stars with radiative envelopes
NASA Astrophysics Data System (ADS)
Kochukhov, Oleg
2014-08-01
Stars with radiative envelopes, specifically the upper main sequence chemically peculiar (Ap) stars, were among the first objects outside our solar system for which surface magnetic fields have been detected. Currently magnetic Ap stars remains the only class of stars for which high-resolution measurements of both linear and circular polarization in individual spectral lines are feasible. Consequently, these stars provide unique opportunities to study the physics of polarized radiative transfer in stellar atmospheres, to analyze in detail stellar magnetic field topologies and their relation to starspots, and to test different methodologies of stellar magnetic field mapping. Here I present an overview of different approaches to modeling the surface fields in magnetic A- and B-type stars. In particular, I summarize the ongoing efforts to interpret high-resolution full Stokes vector spectra of these stars using magnetic Doppler imaging. These studies reveal an unexpected complexity of the magnetic field geometries in some Ap stars.
Transient electromagnetic analysis coupled to electric circuits and motion
C. S. Biddlecombe; J. Simkin; A. P. Jay; J. K. Sykulski; S. Lepaul
1998-01-01
This paper presents implementation details of coupling circuit equations and motion with two dimensional finite clement models for transient magnetic analysis. Finite elements with incomplete shape functions are used in a novel way to handle the interface between the moving and stationary parts of the mesh. The final system of equations can then be solved using adaptive time stepping. Two
Coupled noise analysis for adjacent vias in multilayered digital circuits
Qizheng Gu; M. Ali Tassoudji; Soon Y. Poh; Robert T. Shin; Jin Au Kong
1994-01-01
The electromagnetic coupling between two adjacent vias in a multilayered integrated circuit is analyzed by means of equivalent magnetic frill array models incorporated with the even- and odd-mode approach. Closed-form expressions for the coupled noise on the passive via are derived. The coupling responses in the frequency domain and crosstalk waveforms in the time domain for some multilayered via structures
Simulation of soft magnetic materials by SPICE
Jacek Izydorczyk
2006-01-01
The text concisely shows the algorithm for computation of parameters of Jiles and Atherton (J-A) model of nonlinear magnetic material to simulate it within the SPICE circuit simulator. The model of magnetic material implemented in the SPICE simulator can reproduce hysteresis of the material and can be easy implemented outside the simulator. The presented algorithm is simple and it does
Demonstrations with an "LCR" Circuit
ERIC Educational Resources Information Center
Kraftmakher, Yaakov
2011-01-01
The "LCR" circuit is an important topic in the course of electricity and magnetism. Papers in this field consider mainly the forced oscillations and resonance. Our aim is to show how to demonstrate the free and self-excited oscillations in an "LCR" circuit. (Contains 4 figures.)
Magnetic field measurements of 1. 5 meter model SSC collider dipole magnets at Fermilab
Lamm, M.J.; Bleadon, M.; Coulter, K.J.; Delchamps, S.; Hanft, R.; Jaffery, T.S.; Kinney, W.; Koska, W.; Ozelis, J.P.; Strait, J.; Wake, M. (Fermi National Accelerator Lab., Batavia, IL (United States)); DiMarco, J. (Superconducting Super Collider Lab., Dallas, TX (United States))
1991-09-01
Magnetic field measurements have been performed at Fermilab on 1.5 m magnetic length model dipoles for the Superconducting Supercollider. Harmonic measurements are recorded at room temperature before and after the collared coil is assembled into the yoke and at liquid helium temperature. Measurements are made as a function of longitudinal position and excitation current. High field data are compared with room temperature measurements of both the collared coil and the completed yoked magnet and with the predicted fields for both the body of the magnet and the coil ends.
A model of interplanetary and coronal magnetic fields
Kenneth H. Schatten; John M. Wilcox; Norman F. Ness
1969-01-01
A model of the large-scale magnetic field structure above the photosphere uses a Green's function solution to Maxwell's equations. Sources for the magnetic field are related to the observed photospheric field and to the field computed at a ‘source’ surface about 0.6 R? above the photosphere. The large-scale interplanetary magnetic field sector pattern is related to the field pattern at
Rapid-eye-movement sleep involves the memory-conversion circuits in a brain model.
Wong, C W
2000-11-01
People can remember the content of a dream in rapid eye movement (REM) sleep but cannot do so in slow-wave sleep. According to a brain model, memory is stored in encoding synapses as presynaptic axonal 'on-off' patterns and modulating synapses help encoding synapses convert short-term memory into long-term memory. These lead to the hypothesis that REM sleep involves modulating synapses of the memory-conversion circuits including the anterior nuclei and dorsomedial nuclei of the thalamus. Cortical neurons get more rest in slow-wave sleep than in REM sleep. The locus coeruleus, raphe nuclei, and tuberomammillary nuclei get more rest during REM sleep when these nuclei cease to fire. The paralyses of peripheral muscles during REM sleep and cataplexy, and cessation of chorea, athetosis, hemiballismus, and parkinsonism tremor during sleep may result from spinal cord inhibition by the gigantocellular nuclei and raphe nuclei at the reticular formation. Sleep and wake relate to the light-dark cycle on the Earth. Were the light-dark cycle 50 hours a day, the human circadian clock might be around 50 hours. With increasing use of artificial light to keep people awake at night, it may affect the circadian rhythm and firing rate of neurons, the presynaptic axonal 'on-off' patterns as content of consciousness, and the mood. PMID:11058419