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1

Dynamic analysis of interior permanent magnet motor based on a magnetic circuit model  

Microsoft Academic Search

This paper presents a new magnetic circuit model of an interior permanent magnet (IPM) motor for use in SPICE, which is the general-purpose circuit-simulation program. The magnetic circuit model consists of reluctances and permanent magnet magnetomotive-force sources. In the SPICE simulation, a magnetic circuit model of the IPM motor and its driving circuit are coupled by a proper circuit. Using

Kenji Nakamura; Kenichi Saito; Osamu Ichinokura

2003-01-01

2

An Integrated Magnetic Circuit Model and Finite Element Model Approach to Magnetic Bearing Design  

NASA Technical Reports Server (NTRS)

A code for designing magnetic bearings is described. The code generates curves from magnetic circuit equations relating important bearing performance parameters. Bearing parameters selected from the curves by a designer to meet the requirements of a particular application are input directly by the code into a three-dimensional finite element analysis preprocessor. This means that a three-dimensional computer model of the bearing being developed is immediately available for viewing. The finite element model solution can be used to show areas of magnetic saturation and make more accurate predictions of the bearing load capacity, current stiffness, position stiffness, and inductance than the magnetic circuit equations did at the start of the design process. In summary, the code combines one-dimensional and three-dimensional modeling methods for designing magnetic bearings.

Provenza, Andrew J.; Kenny, Andrew; Palazzolo, Alan B.

2003-01-01

3

12. DEVICES AND APPLICATIONS Abstract --This paper presents a magnetic circuit modeling of  

E-print Network

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 that there are a lot of flux leakages. Fig. 2: Flux density modulus inside the magnetic circuit. Modeling of a current

Paris-Sud XI, Université de

4

3D magnetic equivalent circuit model for homopolar hybrid excitation synchronous machines  

Microsoft Academic Search

A 3D magnetic equivalent circuit model is developed to predict the total excitation flux of an homopolar hybrid excitation synchronous machines. It is established using the main flux path and a part of the magnets leakage flux's path. This model takes into account the lamination effect and ferromagnetic parts reluctances. Results from the model are compared with finite-element predictions and

C. Bekhaled; S. Hlioui; L. Vido; M. Gabsi; M. Lecrivain; Y. Amara

2007-01-01

5

Magnetic Circuit Model of PM Motor-Generator to Predict Radial Forces  

NASA Technical Reports Server (NTRS)

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.

McLallin, Kerry (Technical Monitor); Kascak, Peter E.; Dever, Timothy P.; Jansen, Ralph H.

2004-01-01

6

Testing Circuit Models for the Energies of Coronal Magnetic Field Configurations  

E-print Network

Circuit models involving bulk currents and inductances are often used to estimate the energies of coronal magnetic field configurations, in particular configurations associated with solar flares. The accuracy of circuit models is tested by comparing calculated energies of linear force-free fields with specified boundary conditions with corresponding circuit estimates. The circuit models are found to provide reasonable (order of magnitude) estimates for the energies of the non-potential components of the fields, and to reproduce observed functional dependences of the energies. However, substantial departure from the circuit estimates is observed for large values of the force-free parameter, and this is attributed to the influence of the non-potential component of the field on the path taken by the current.

M. S. Wheatland; F. J. Farvis

2003-11-02

7

Magnetic switches and circuits  

SciTech Connect

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.

Nunnally, W.C.

1982-05-01

8

A Magnetic Circuit Demonstration.  

ERIC Educational Resources Information Center

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)

Vanderkooy, John; Lowe, June

1995-01-01

9

Magnetic circuit model for the mutually coupled switched-reluctance machine  

Microsoft Academic Search

The mutually coupled switched-reluctance motor (SRM) appears to have several performance advantages over other motor technologies. The existence of strong coupling between phases, however, makes the analysis of this machine quite complicated. Preliminary design of this machine can be greatly accelerated by the ability to evaluate potential motor geometries quickly. This paper introduces a general magnetic circuit model of the

James M. Kokernak; David A. Torrey

2000-01-01

10

Analysis of electromagnetic performance of flux-switching permanent-magnet Machines by nonlinear adaptive lumped parameter magnetic circuit model  

Microsoft Academic Search

A nonlinear adaptive lumped parameter magnetic circuit model is developed to predict the electromagnetic performance of a flux-switching permanent-magnet machine. It enables the air-gap field distribution, the back-electromotive force (back-EMF) waveform, the winding inductances, and the electromagnetic torque to be calculated. Results from the model are compared with finite-element predictions and validated experimentally. The influence of end effects is also

Z. Q. Zhu; Y. Pang; D. Howe; S. Iwasaki; R. Deodhar; A. Pride

2005-01-01

11

Equivalent Electric Circuit Models of Coronal Magnetic Loops and Related Oscillatory Phenomena on the Sun  

NASA Astrophysics Data System (ADS)

Coronal loops, which trace closed magnetic field lines, are the primary structural elements of the solar atmosphere. Complex dynamics of solar coronal magnetic loops, together with action of possible subphotospheric dynamo mechanisms, turn the majority of the coronal loops into current-carrying structures. In that connection none of the loops can be considered as isolated from the surroundings. The current-carrying loops moving relative to each other interact via the magnetic field and currents. One of the ways to take into account this interaction consists in application of the equivalent electric circuit models of coronal loops. According to these models, each loop is considered as an equivalent electric LCR-circuit with variable inductive coefficients L, capacitance C, and resistance R, which depend on shape, scale, position of the loop with respect to neighbouring loops, as well as on the plasma parameters in the magnetic tube. Such an approach enables to describe the process of electric current dynamics in the groups of coronal loops, as well as the related dynamical, energy release and radiation processes. In the present paper we describe the major principles of LCR-circuit models of coronal magnetic loops, and show their application for interpretation of the observed oscillatory phenomena in the loops and in the related radiation.

Khodachenko, Maxim L.; Zaitsev, Valerii V.; Kislyakov, Albert G.; Stepanov, Alexander V.

2009-12-01

12

Equivalent-circuit models for the design of metamaterials based on artificial magnetic inclusions  

Microsoft Academic Search

In this paper, we derive quasi-static equivalent-circuit models for the analysis and design of different types of artificial magnetic resonators—i.e., the multiple split-ring resonator, spiral resonator, and labyrinth resonator—which represent popular in- clusions to synthesize artificial materials and metamaterials with anomalous values of the permeability in the microwave and mil- limeter-wave frequency ranges. The proposed models, derived in terms of

Filiberto Bilotti; Alessandro Toscano; Lucio Vegni; Koray Aydin; Kamil Boratay Alici; Ekmel Ozbay

2007-01-01

13

Quantum Circuit Model Topological Model  

E-print Network

Quantum Circuit Model Topological Model Comparison of Models Topological Quantum Computation Eric Rowell Texas A&M University October 2010 Eric Rowell Topological Quantum Computation #12;Quantum Circuit Model Topological Model Comparison of Models Outline 1 Quantum Circuit Model Gates, Circuits

Rowell, Eric C.

14

Modeling, analysis and design of integrated magnetics for modern power electronics circuits  

Microsoft Academic Search

Summary form only as given. In modern power electronic circuits, such as power-factor-corrected regulators and cascaded converters, multiple numbers of electronic switches and magnetic components are often used. A lot of research work has been carried out to integrate the electronic switches so as to reduce the number of switches required and the cost. However, not much systematic work on

D. K. W. Cheng; L. P. Wong; Y. S. Lee

1999-01-01

15

IEEE TRANSACTIONS ON MAGNETICS, VOL 31, NO 6, NOVEMBER 1995 4065 Modeling of a Non-Linear Conductive Magnetic Circuit  

E-print Network

, magnetic formulations have to be performed. The classical self-inductance and mutual inductance quantities by the quasi-static characteristic, with no time dependence thus excitation inputs. For a conductive circuit. To take into account the hysteresis phenomena we substitutethis static characteristic by stahc generator

Paris-Sud XI, Université de

16

Dynamical Models for Eddy Current in Ferromagnetic Cores Introduced in an FE-Tuned Magnetic Equivalent Circuit of an Electromagnetic Relay  

Microsoft Academic Search

Electromagnetic relay modeling is elaborated using a magnetic equivalent circuit (MEC). The lumped parameters of the MEC are fitted with respect to 3-D finite-element simulation by using classical optimization algorithms. An accurate dynamic material law has to be taken into account in the modeling, considering the massive core of the circuit. Two accurate dynamical models for representing eddy currents are

Fabien Sixdenier; Marie-Ange Raulet; Romain Marion; René Goyet; Guy Clerc; Farid Allab

2008-01-01

17

A Differential Magnetic Circuit for Teaching Purposes  

ERIC Educational Resources Information Center

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…

Kraftmakher, Yaakov

2010-01-01

18

Analysis and design of a coreless permanent-magnet machine considering the winding shape by using a lumped equivalent magnetic circuit model  

NASA Astrophysics Data System (ADS)

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.

Seo, Jung-Moo; Jung, In-Soung; Jung, Hyun-Kyo; Ro, Jong-Suk

2014-05-01

19

Designing HTS coils for magnetic circuits  

SciTech Connect

The authors discuss some of the main considerations involved in the design of HTS coils to operate in liquid nitrogen and provide ampere-turns for magnetic circuits in general, and then in particular for a small-scale electromagnetic (i.e, attractive) maglev demonstrator. The most important factor affecting design is the sensitive and strongly anisotropic dependence of HTS tape`s critical current on magnetic field. Any successful design must limit the field in the windings, especially components perpendicular to the tape`s surface (radial components in the case of solenoids), to acceptably low levels such that local critical currents nowhere fall below the operating current. This factor is relevant to the construction of HTS coils for all applications. A second important factor is that the presence of an iron magnetic circuit can greatly alter the flux distribution within the coils from that found when they are in free space. FE modelling has been used to calculate accurate field profiles in proposed designs for comparison with short sample I{sub c}(B) data. They present a design for a maglev demonstrator, illustrating how some of the problems, in particular the reduction of radial field components, may be addressed, and describe its predicted performance.

Jenkins, R.G.; Jones, H. [Univ. of Oxford (United Kingdom). Clarendon Lab.] [Univ. of Oxford (United Kingdom). Clarendon Lab.; Goodall, R.M. [Loughborough Univ. of Technology (United Kingdom). Dept. of Electronic and Electrical Engineering] [Loughborough Univ. of Technology (United Kingdom). Dept. of Electronic and Electrical Engineering

1996-07-01

20

Modeling cortical circuits.  

SciTech Connect

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.

Rohrer, Brandon Robinson; Rothganger, Fredrick H.; Verzi, Stephen J.; Xavier, Patrick Gordon

2010-09-01

21

Statistical circuit modeling and optimization  

Microsoft Academic Search

This tutorial reviews statistical circuit modeling and optimization and its applications in integrated circuit design. Motivated by a discussion of the importance of statistical design techniques, it introduces the primary concepts and discusses the main techniques used for statistical modeling, analysis and optimization. It also considers some of the important open questions

Steven G. Duvall

2000-01-01

22

Closed Circuit Television Model Program.  

ERIC Educational Resources Information Center

The resources of closed circuit television can improve teaching and learning in schools. Three junior high schools in Arlington Heights, Illinois have inaugurated a closed circuit television model program. The program's objectives are improvement of the quality of standard teacher-lesson presentations, redirection of teacher time and energy to…

Elms, Glen D.

23

Notes on Magnetic Circuits ME 104, Prof. B. Paden  

E-print Network

-clockwise, the direction of flux when there is a positive current. To understand this magnetic circuit, we deriveNotes on Magnetic Circuits ME 104, Prof. B. Paden Magnetic circuits play an important role, magnetic bearings, electromagnetic latches, proximity sensors, and resolvers. A good starting place

Paden, Brad

24

Classical Ising model test for quantum circuits  

E-print Network

We exploit a recently constructed mapping between quantum circuits and graphs in order to prove that circuits corresponding to certain planar graphs can be efficiently simulated classically. The proof uses an expression for the Ising model partition function in terms of quadratically signed weight enumerators (QWGTs), which are polynomials that arise naturally in an expansion of quantum circuits in terms of rotations involving Pauli matrices. We combine this expression with a known efficient classical algorithm for the Ising partition function of any planar graph in the absence of an external magnetic field, and the Robertson-Seymour theorem from graph theory. We give as an example a set of quantum circuits with a small number of non-nearest neighbor gates which admit an efficient classical simulation.

J. Geraci; D. A. Lidar

2009-02-27

25

The study of magnetic circuit control technology for permanent magnet hump rail brake  

NASA Astrophysics Data System (ADS)

This paper introduced a hump rail brake equipment which used the Nd-Fe-B permanent magnet as the energy source of brake force and the control theory of the magnetic circuit. The paper focused on bringing forward a design theory and methods of the key permanent magnetic parts, calculated the magnetic circuit and simulated the magnetic system with the ANSYS software. Through analyzing the results of the machined model parts, this equipment reached the actual application level and provided a new economic energy solving scheme for hump velocity control.

Li, Xiang; Li, Desheng; Chong, Chuanbo; Ye, Lezhi; Lu, Zhiyuan

2006-11-01

26

Didactic Considerations on Magnetic Circuits Excited by Permanent Magnets  

ERIC Educational Resources Information Center

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…

Barmada, S.; Rizzo, R.; Sani, L.

2009-01-01

27

Nonlinear varying-network magnetic circuit analysis for doubly salient permanent-magnet motors  

Microsoft Academic Search

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

Ming Cheng; K. T. Chau; C. C. Chan; E. Zhou; X. Huang

2000-01-01

28

Equivalent circuit models for the analysis of electric response and magnetic response of compact triangular electromagnetic resonator  

NASA Astrophysics Data System (ADS)

The equivalent circuit model (ECM) and the design of compact triangular electromagnetic resonator (TER) are both introduced in this paper. ECM with analytic expressions is utilized to obtain the dispersion curves of effective permittivity and effective permeability of four kinds of TER with/without interdigital capacitor. Compared with effective parameters obtained by the parametric retrieval algorithm using simulated and measured s-parameters, the results of ECM correspond very well with the two results above, which demonstrates the effectiveness of ECM and provides us a new way to analyze the effective parameters of metamaterials.

Zhu, Cheng; Li, Ke; Chen, Yang; Li, Tong; Zhai, Hui-Qing; Li, Long; Liang, Chang-Hong

2013-01-01

29

CMOS magnetic sensor integrated circuit with sectorial MAGFET  

Microsoft Academic Search

In this paper, a CMOS magnetic sensor integrated circuit (IC) for a perpendicular magnetic field is introduced. The sensor integrated circuit is designed and fabricated in a 0.6?m digital CMOS process. It consists of a pair of common-source split-drain magnetic field-effect transistor (MAGFET), a pre-processing circuit with a switches array, a correlated double sampling (CDS) circuit and a digital controlling

Guo Qing; Zhu Dazhong; Yao Yunruo

2006-01-01

30

Magnetic equivalent circuit of PM hysteresis synchronous motor  

Microsoft Academic Search

This paper presents the magnetic equivalent circuit of a permanent magnet hysteresis synchronous motor (PMHS). The hybrid synchronous motor consists of 36% cobalt steel hysteresis alloys with neodymium iron boron permanent magnets to improve the overall performances of such a motor. Based on the magnetic equivalent circuit, the control strategy of the PMHS motor is developed. Experimental results confirm the

R. Qin; M. A. Rahman

2003-01-01

31

Semiconductor Circuit Diagnostics By Magnetic Field Imaging  

NASA Astrophysics Data System (ADS)

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 ˜ 20pT/(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 (˜250nm) is obtained by the use of magneto-resistive devices as sensors though the working distance requirement is sever

Venkatesan, T.

2011-03-01

32

Reconfigurable Circuits Using Magnetic Tunneling Junction Memories  

NASA Astrophysics Data System (ADS)

This paper presents the first results of our work to research and develop new reconfigurable circuits and topologies based on Magnetic RAM (MRAM) memory elements. This work proposes a coarse-grained reconfigurable array using MRAM. A coarse-grained array, where each reconfigurable element computes on 4-bit or larger input words, is more suitable to execute data-oriented algorithms and is more able to exploit large amounts of operation-level parallelism than common fine-grained architectures. The architecture is organized as a one-dimensional array of programmable ALU and the configuration bits are stored in MRAM. MRAM provide non-volatility with cell areas and with access speeds comparable to those of SRAM and with lower process complexity than FLASH memory. MRAM can also be efficiently organized as multi-context memories.

Silva, Victor; Fernandes, Jorge; Neto, Horácio

33

Computing with Neural Circuits: A Model  

Microsoft Academic Search

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

John J. Hopfield; David W. Tank

1986-01-01

34

Magnetoelectric sensor with miniature universal tunable bias magnetic circuit  

NASA Astrophysics Data System (ADS)

This paper presents a miniature alternating magnetic field sensor made from magnetoelectric (ME) laminated materials with a universal tunable bias magnetic circuit. By adjusting the width of the bypass passage in the bias magnetic circuit, the magnetic flux in the ME materials could be tuned and make the ME sensor work under the optimal bias magnetic field. In our design, the sensor's dimension is as small as 8 mm along the detecting direction. Due to the excellent linearity when measuring low frequency alternating magnetic fields of 50 Hz, this miniature sensor is ideally suited for power line current measurement.

Shi, Zhan; Tong, Yongshuai; Deng, Shuwen; Xue, Hao; Yang, Shuiyuan; Lu, Yong; Wang, Cuiping; Liu, Xingjun

2013-07-01

35

An equivalent circuit and simulation analysis of magnetically-saturated controllable reactors  

Microsoft Academic Search

Introducing the concept of equivalent currents, this paper proposes a very simple mathematical model for a magnetically-saturated controllable reactor (MSCR). When the primary windings of two identical transformers are positively series and the secondary windings are negatively series, an equivalent circuit for such kind of reactors can be thus derived. This circuit exactly manifests the physical discipline of the mathematical

Mingxing Tian; Qingfu Li; Qunfeng Li

2003-01-01

36

Magnetic equivalent circuit of PM hysteresis synchronous motor  

Microsoft Academic Search

This paper presents the magnetic equivalent circuit of a permanent magnet hysteresis synchronous (PMHS) motor. The hybrid synchronous motor consists of 30% Cobalt-steel hysteresis alloys Neodymium Iron Boron (NdFeB) permanent magnets to improve the overall performances of motors.

Ruifeng Qin; M. A. Rahman

2003-01-01

37

Analog Circuit Testing Based on Sensitivity Computation and New Circuit Modeling  

Microsoft Academic Search

Analog circuit testing is considered to be a very difficult task, due mainly to the lack of fault models and accessibility to internal nodes. An approach is presented for analog circuit modeling and testing to overcome this problem. This circuit modeling is based on a sensitivity computation and on circuit structure, which are crucial in analog circuit testing. The testability

Naim Ben Hamida; Bozena Kaminska

1993-01-01

38

Equivalent Circuit Modeling of Hysteresis Motors  

Microsoft Academic Search

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

J J Nitao; E T Scharlemann; B A Kirkendall

2009-01-01

39

Split circuit model for test generation  

Microsoft Academic Search

Over the years, the D-algorithm has been successfully used to generate tests for sequential circuits and combinational circuits. There are 5-valued and 9-valued circuit models used for the D-algorithm. The disadvantage of a model with lower value count is its inability to assign a more precise value for a test generation requirement without some undue assumptions or decisions which may

Wu-Tung Cheng

1988-01-01

40

Circuit modeling of multimode bistable laser diodes  

Microsoft Academic Search

A circuit model for multimode bistable laser diodes (BLD) has been developed from the rate equations. The model is simulated for dc sweep and transient conditions using circuit simulation program PSPICE. The hysteresis behaviour and the dynamic properties of the longitudinal modes of the BLD are studied. The dc sweep simulation shows “S”-shaped bistability for the fundamental mode, whereas the

M. Ganesh Madhan; P. R. Vaya; N. Gunasekaran

1999-01-01

41

Equivalent Circuit Modeling of Hysteresis Motors  

SciTech Connect

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.

Nitao, J J; Scharlemann, E T; Kirkendall, B A

2009-08-31

42

DC Circuit Powered by Orbital Motion: Magnetic Interactions in Compact Object Binaries and Exoplanetary Systems  

E-print Network

The unipolar induction DC circuit model, originally developed by Goldreich & Lynden-Bell for the Jupiter-Io system, has been applied to different types of binary systems in recent years. We show that there exists an upper limit to the magnetic interaction torque and energy dissipation rate in such model. This arises because when the resistance of the circuit is too small, the large current flow severely twists the magnetic flux tube connecting the two binary components, leading to breakdown of the circuit. Applying this limit, we find that in coalescing neutron star binaries, magnetic interactions produce negligible correction to the phase evolution of the gravitational waveform, even for magnetar-like field strengths. However, energy dissipation in the binary magnetosphere may still give rise to electromagnetic radiation prior to the final merger. For ultra-compact white dwarf binaries, we find that DC circuit does not provide adequate energy dissipation to explain the observed X-ray luminosities of seve...

Lai, Dong

2012-01-01

43

Quantum computation beyond the circuit model  

E-print Network

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, ...

Jordan, Stephen Paul

2008-01-01

44

Use of magnetic materials in excimer laser circuits  

SciTech Connect

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.

Vannini, M.; Sze, R.; Hommeau, F.

1987-01-01

45

Synthesis of averaged circuit models for switched power converters  

Microsoft Academic Search

An approach for synthesizing averaged circuit models for switching converters that realize their respective state-space averaged models is presented. The method proceeds in a systematic fashion by determining appropriate averaged circuit elements that are consistent with the averaged circuit waveforms. The averaged circuit models that are obtained are syntheses of the state-space averaged models for the underlying switched circuits. An

Seth R. Sanders; George C. Verghese

1991-01-01

46

Compact modeling of circuits and devices in Verilog-A  

E-print Network

The compact model of a circuit or device is a system of linear and/or nonlinear differential equations that effectively models the behavior of the circuit or device. Compact modeling plays a critical role in circuit ...

Mysore, Omar

2012-01-01

47

Quantum Computation Beyond the "Standard Circuit Model"  

E-print Network

Construction of explicit quantum circuits follows the notion of the "standard circuit model" introduced in the solid and profound analysis of elementary gates providing quantum computation. Nevertheless the model is not always optimal (e.g. concerning the number of computational steps) and it neglects physical systems which cannot follow the "standard circuit model" analysis. We propose a computational scheme which overcomes the notion of the transposition from classical circuits providing a computation scheme with the least possible number of Hamiltonians in order to minimize the physical resources needed to perform quantum computation and to succeed a minimization of the computational procedure (minimizing the number of computational steps needed to perform an arbitrary unitary transformation). It is a general scheme of construction, independent of the specific system used for the implementation of the quantum computer. The open problem of controllability in Lie groups is directly related and rises to prominence in an effort to perform universal quantum computation.

K. Ch. Chatzisavvas; C. Daskaloyannis; C. P. Panos

2005-07-18

48

MOSFET substrate current model for circuit simulation  

Microsoft Academic Search

A simple, accurate MOSFET substrate current model suitable for a circuit simulator is presented. The effect of substrate bias on substrate current is modeled without introducing additional parameters. The accuracy of this model is demonstrated by its ability to fit the experimental data for both standard and LDD devices with average errors of less than 6%. The new model is

Narain D. Arora; Mahesh S. Sharma

1991-01-01

49

Circuit models for Sierpinski gasket antennas  

E-print Network

A lumped-parameter impedor-oriented and a 2-port-network-oriented circuit models for the Sierpinski gasket prefractal antenna are presented. With the former, the voltage and current patterns give a detailed understanding of the electromagnetic fields' self-similar distribution throughout the antenna geometry; on the other hand model complexity exponentially increases with the prefractal iteration order. The latter "black-box" model only controls port-oriented global parameters which are the ones commonly used in antennas' circuit models and its complexity is independent of prefractal order. The "black-box" model is also shown to converge, at fractal limit, to a reciprocal triangular network.

Arrighetti, W; Gerosa, G

2005-01-01

50

Energy Consumption Calculation of Permanent Magnet Synchronous Motor for Railway Vehicle Traction Using Equivalent Circuit  

Microsoft Academic Search

We are developing a new high performance traction motor for railway vehicle using interior permanent magnet synchronous motor (IPMSM) and expecting it can reduce energy consumption. To estimate the losses and energy consumption of IPMSM, a simple motor model is needed. In this paper, We propose a simple equivalent circuit and loss model for IPMSM, the constants of which can

Minoru Kondo; Junya Kawamura; Nobuo Terauchi

2005-01-01

51

Magnetic Field Analysis of Lorentz Motors Using a Novel Segmented Magnetic Equivalent Circuit Method  

PubMed Central

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

Qian, Junbing; Chen, Xuedong; Chen, Han; Zeng, Lizhan; Li, Xiaoqing

2013-01-01

52

Magnetic field analysis of Lorentz motors using a novel segmented magnetic equivalent circuit method.  

PubMed

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

Qian, Junbing; Chen, Xuedong; Chen, Han; Zeng, Lizhan; Li, Xiaoqing

2013-01-01

53

Multiple coupled circuit modeling of induction machines  

Microsoft Academic Search

A 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 is

X. Luo; Yuefeng Liao; H. Toliyat; A. El-Antably; T.A. Lipo

1993-01-01

54

Multiple coupled circuit modeling of induction machines  

Microsoft Academic Search

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

Xiaogang Luo; Yuefeng Liao; H. A. Toliyat; A. El-Antably; T.A. Lipo

1995-01-01

55

Equivalent Circuit Modeling of Hysteresis Motors.  

National Technical Information Service (NTIS)

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,...

B. A. Kirkendall, E. T. Scharlemann, J. J. Nitao

2009-01-01

56

Resonant circuit model for efficient metamaterial absorber.  

PubMed

The resonant absorption in a planar metamaterial is studied theoretically. We present a simple physical model describing this phenomenon in terms of equivalent resonant circuit. We discuss the role of radiative and dissipative damping of resonant mode supported by a metamaterial in the formation of absorption spectra. We show that the results of rigorous calculations of Maxwell equations can be fully retrieved with simple model describing the system in terms of equivalent resonant circuit. This simple model allows us to explain the total absorption effect observed in the system on a common physical ground by referring it to the impedance matching condition at the resonance. PMID:24514941

Sellier, Alexandre; Teperik, Tatiana V; de Lustrac, André

2013-11-01

57

Modeling "Soft" Errors in Bipolar Integrated Circuits  

NASA Technical Reports Server (NTRS)

Mathematical models represent single-event upset in bipolar memory chips. Physics of single-event upset in integrated circuits discussed in theoretical paper. Pair of companion reports present mathematical models to predict critical charges for producing single-event upset in bipolar randomaccess memory (RAM) chips.

Zoutendyk, J.; Benumof, R.; Vonroos, O.

1985-01-01

58

Statistical Circuit Simulation Modeling of CMOS VLSI  

Microsoft Academic Search

This paper describes a complete modeling approach for MOS VLSI circuit design which is highly automated and provides statistically relevant parameter files. A description of key model equations, which includes the effects of nonuniformly doped channels, charge sharing bulk-charge terms, and lateral and vertical field mobility reduction terms, will be given. A methodology of parameter extraction for both physical and

Norm Herr; John J. Barnes

1986-01-01

59

Equivalent Circuit Models for Three-Dimensional Multiconductor Systems  

Microsoft Academic Search

Multiconductor or multiwire arrangements find many applications in electronic systems. Examples are interconnections between digital circuits or integrated microwave circuits. Equivalent circuit models are derived here from an integral equation to establish an electrical description of the physical geometry. The models, which are appropriately called partial element equivalent circuits (PEEC), are general in that they include losses. Models of different

ALBERT E. RUEHLI

1974-01-01

60

High bandwidth magnetically isolated signal transmission circuit  

NASA Technical Reports Server (NTRS)

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.

Repp, John Donald (Inventor)

2005-01-01

61

DC Circuit Powered by Orbital Motion: Magnetic Interactions in Compact Object Binaries and Exoplanetary Systems  

E-print Network

The unipolar induction DC circuit model, originally developed by Goldreich & Lynden-Bell for the Jupiter-Io system, has been applied to different types of binary systems in recent years. We show that there exists an upper limit to the magnetic interaction torque and energy dissipation rate in such model. This arises because when the resistance of the circuit is too small, the large current flow severely twists the magnetic flux tube connecting the two binary components, leading to breakdown of the circuit. Applying this limit, we find that in coalescing neutron star binaries, magnetic interactions produce negligible correction to the phase evolution of the gravitational waveform, even for magnetar-like field strengths. However, energy dissipation in the binary magnetosphere may still give rise to electromagnetic radiation prior to the final merger. For ultra-compact white dwarf binaries, we find that DC circuit does not provide adequate energy dissipation to explain the observed X-ray luminosities of several sources. For exoplanetary systems containing close-in Jupiters or super-Earths, magnetic torque and dissipation are negligible, except possibly during the early T Tauri phase, when the stellar magnetic field is stronger than 10^3G.

Dong Lai

2012-06-17

62

Linear induction motor - Equivalent-circuit model  

Microsoft Academic Search

An equivalent-circuit model of a linear induction motor is developed, using the rotary-motor model as a basis. The rotary-motor model is modified to account for the so-called 'end effect' and is used to predict output thrust, vertical forces and couples. These predictions are checked against test results of a practical motor used on a prototype transit vehicle.

J. Duncan

1983-01-01

63

Magnetic field measurements of printed-circuit quadrupoles and dipoles  

Microsoft Academic Search

Printed-Circuit (PC) quadrupoles and dipoles have been designed and developed for focusing and bending a space-charge dominated electron beam in the University of Maryland Electron Ring (UMER), currently under development. Due to the rather small aspect ratio (length\\/diameter <1) of the magnets, the field quality, especially the nonlinear fringe field, has been a concern for the success of the UMER

W. W. Zhang; S. Bernal; P. Chin; R. Kishek; M. Reiser; M. Venturini; J. G. Wang; V. Yun

1999-01-01

64

Proposal of Magnetic Circuit using Magnetic Shielding with Bulk-Type High Tc Superconductors  

Microsoft Academic Search

Recently, bulk-type high Tc superconductors having a characteristic of critical current density over 104 A\\/cm2 in liquid nitrogen temperature (77K) on 1T, can be produced. They are promising for many practical applications such as a magnetic bearing, a magnetic levitation, a flywheel, a magnetic shielding and others. In this research, we propose a magnetic circuit that is able to use

Katsuhiro Fukuoka; Mitsuo Hashimoto; Masaru Tomita; Masato Murakami

2003-01-01

65

Field-Circuit Hybrid Method for Magnetic Actuator Using a Laminate Composite  

Microsoft Academic Search

The magnetic actuator using a laminate composite of piezoelectric (PZT) and magnetostrictive materials (MM) achieves active control of magnetic force without Joule heat loss. To study its characteristics, the field-circuit hybrid method is proposed based on the equivalent magnetic circuit and the finite element analysis (FEA) of piezoelectric and magnetic fields. The strain of laminate composite under different voltage is

Bin Li; Chang-Liang Xia; Ting-Na Shi; Hong-Feng Li

2009-01-01

66

Model Reduction for a Class of Nonlinear Electrical Circuits  

E-print Network

Model Reduction for a Class of Nonlinear Electrical Circuits by Reduction of Linear Subcircuits of the original circuit equations and that of our reduced-order model. These bounds are valid for all inputs: electrical circuits, passive systems, model reduction, modified nodal analysis 1. Introduction Model

Reis, Timo

67

DC Circuit Powered by Orbital Motion: Magnetic Interactions in Compact Object Binaries and Exoplanetary Systems  

NASA Astrophysics Data System (ADS)

The unipolar induction DC circuit model, originally developed by Goldreich and Lynden-Bell for the Jupiter-Io system, has been applied to different types of binary systems in recent years. We show that there exists an upper limit to the magnetic interaction torque and energy dissipation rate in such a model. This arises because when the resistance of the circuit is too small, the large current flow severely twists the magnetic flux tube connecting the two binary components, leading to the breakdown of the circuit. Applying this limit, we find that in coalescing neutron star binaries, magnetic interactions produce negligible correction to the phase evolution of the gravitational waveform, even for magnetar-like field strengths. However, energy dissipation in the binary magnetosphere may still give rise to electromagnetic radiation prior to the final merger. For ultracompact white dwarf binaries, we find that unipolar induction does not provide adequate energy dissipation to explain the observed X-ray luminosities of several sources. For exoplanetary systems containing close-in Jupiters or super-Earths, the magnetic torque and energy dissipation induced by the orbital motion are negligible, except possibly during the early T Tauri phase, when the stellar magnetic field is stronger than 103 G.

Lai, Dong

2012-09-01

68

Stochastic Computational Models for Accurate Reliability Evaluation of Logic Circuits  

E-print Network

Stochastic Computational Models for Accurate Reliability Evaluation of Logic Circuits Hao Chen the evaluation of large circuits intractable. This paper presents novel computational models based on stochastic, for the reliability evaluation of logic circuits. A computational approach using the stochastic computational models

Han, Jie

69

Structure-Preserving Model Order Reduction of RCL Circuit Equations  

E-print Network

Structure-Preserving Model Order Reduction of RCL Circuit Equations Roland W. Freund Department circuit. In this paper, we describe the problem of structure-preserving model order reduction of general-order model to maintain the passivity properties of the orig- inal circuit. In [23, 24, 4], it is shown

Freund, Roland W.

70

Biophysical Models of Neural Computation: Max and Tuning Circuits  

E-print Network

Biophysical Models of Neural Computation: Max and Tuning Circuits Ulf Knoblich, Jake Bouvrie realistic circuits for the maximum and tuning operations utilized by this model. There are several possible circuit designs that can theoretically provide the level of robustness required by model simulations

Poggio, Tomaso

71

Formal Verification of Digital Circuits Using Symbolic Ternary System Models  

E-print Network

Formal Verification of Digital Circuits Using Symbolic Ternary System Models Randal E. Bryant. By making this extension, we can model a wider range of circuit phenomena. We can also efficiently verify a ternary system model. The desired behavior of the circuit is expressed as assertions in a notation using

Bryant, Randal E.

72

Unfaithful Glitch Propagation in Existing Binary Circuit Models  

E-print Network

Unfaithful Glitch Propagation in Existing Binary Circuit Models Matthias F¨ugger Embedded Computing that no existing continuous-time, binary value-domain model for digital circuits is able to correctly capture models, which follows from well-known results on the behavior of bi-stable circuits obtained by Marino

Paris-Sud XI, Université de

73

Small signal equivalent circuit modeling of resonant converters  

Microsoft Academic Search

A general analytical procedure is presented for the equivalent circuit modeling of resonant converters, using the series and parallel resonant converters as examples. The switched tank elements of a resonant converter are modeled by a lumped parameter equivalent circuit. The tank element circuit model consists, in general, of discrete energy states, but may be approximated by a low-frequency continuous time

Arthur F. Witulski; Adhn F. Hernandez; Robert W. Erickson

1991-01-01

74

Equivalent circuit modeling of interconnects from time-domain measurements  

Microsoft Academic Search

A technique for the equivalent circuit modeling of single and coupled uniform and nonuniform interconnects, including discontinuities such as bends and junctions in high-speed circuits and packages, is presented. The circuit models are extracted from time-domain reflection and transmission measurement (TDR\\/T). The SPICE simulated results for the extracted circuit models for typical single and coupled structures are compared with the

Jyh-Ming Jong; Bozidar Janko; Vijai Tripathi

1993-01-01

75

Resonant frequency and bandwidth of metamaterial emitters and absorbers predicted by an RLC circuit model  

NASA Astrophysics Data System (ADS)

Metamaterial thermal emitters and absorbers have been widely studied for different geometric patterns by exciting a variety of electromagnetic resonances. A resistor-inductor-capacitor (RLC) circuit model is developed to describe the magnetic resonances (i.e. magnetic polaritons) inside the structures. The RLC circuit model allows the prediction of not only the resonance frequency, but also the full width at half maximum and quality factor for various geometric patterns. The parameters predicted by the RLC model are compared with the finite-difference time-domain simulation. The magnetic field distribution and the power dissipation density profile are also used to justify the RLC circuit model. The geometric effects on the resonance characteristics are elucidated in the wire (or strip), cross, and square patterned metamaterial in the infrared region. This study will facilitate the design of metamaterial absorbers and emitters based on magnetic polaritons.

Sakurai, Atsushi; Zhao, Bo; Zhang, Zhuomin M.

2014-12-01

76

A Nine-Valued Circuit Model for Test Generation  

Microsoft Academic Search

A nine-valued circuit model for test generation is introduced which takes care of multiple and repeated effects of a fault in sequential circuits. Using this model test sequences can be determined which allow multiple and repeated effects of faults on the internal state of a sequential circuit. Thus valid test sequences are derived where other known procedures, like the D-algorithm,

Peter Muth

1976-01-01

77

Modeling Advanced Avalanche Effects for Bipolar Transistor Circuit Design  

E-print Network

Modeling Advanced Avalanche Effects for Bipolar Transistor Circuit Design Vladimir Milovanovi operating frequency and high output power of modern bipolar transistor circuits increase, designers are trying to exploit transistor operating regions where they would be able satisfy both conditions, namely

Technische Universiteit Delft

78

Implementation of a Statistical Model as Integrated Circuits.  

National Technical Information Service (NTIS)

This report discusses the implementation of a statistical model as an integrated analog circuit. Compared to a PC solution, an integrated circuit has the advantage of a potential for increased clock speed and increased parallel computation capability, les...

J. M. Oestby

1996-01-01

79

OPTIMAL SIZE INTEGER DIVISION CIRCUITS 913 computation. In 3 (dealing with polynomial reciprocals) we use a circuit model with  

E-print Network

reciprocals) we use a circuit model with operations in an arbitrary ring as the basis. Optimal algorithms have complexity of O(log n) depth multiplication using the circuit model, then the best known results are due. Unfortunately, this method does not carry over to the circuit model for size O(M(n)) division circuits, we

Reif, John H.

80

Noise analysis of a current-mode read circuit for sensing magnetic tunnel junction resistance  

Microsoft Academic Search

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.

Michael J. Hall; Viktor Gruev; Roger D. Chamberlain

2011-01-01

81

3-D analysis of permanent magnet linear synchronous motor with magnet arrangement using equivalent magnetic circuit network method  

SciTech Connect

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.

Jung, I.S.; Hur, J.; Hyun, D.S.

1999-09-01

82

Linear circuit models for on-chip quantum electrodynamics  

E-print Network

We present equivalent circuits that model the interaction of microwave resonators and quantum systems. The circuit models are derived from a general interaction Hamiltonian. Quantitative agreement between the simulated resonator transmission frequency, qubit Lamb shift and experimental data will be shown. We demonstrate that simple circuit models, using only linear passive elements, can be very useful in understanding systems where a small quantum system is coupled to a classical microwave apparatus.

Alpár Mátyás; Christian Jirauschek; Federico Peretti; Paolo Lugli; György Csaba

2011-06-17

83

The Design of a RapidDischarge Varistor System for the MICE Magnet Circuits  

SciTech Connect

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.

Green, Michael A.

2008-07-23

84

Quantum Computation Beyond the Circuit Model  

E-print Network

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.

Stephen P. Jordan

2008-09-13

85

Computation of magnetic suspension of maglev systems using dynamic circuit theory  

SciTech Connect

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.

He, J.L.; Rote, D.M.; Coffey, H.T.

1991-01-01

86

Computation of magnetic suspension of maglev systems using dynamic circuit theory  

NASA Technical Reports Server (NTRS)

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.

He, J. L.; Rote, D. M.; Coffey, H. T.

1992-01-01

87

Circuit models for three-dimensional geometries including dielectrics  

Microsoft Academic Search

The partial element equivalent circuit (PEEC) approach has proved useful for modeling many different electromagnetic problems. The technique can be viewed as an approach for the electrical circuit modeling for arbitrary 3-D geometries. Recently, the authors extended the method to include retardation with the rPEEC models. So far the dielectrics have been taken into account only in an approximate way.

Albert E. Ruehli; Hansruedi Heeb

1992-01-01

88

Characterization and Modeling of TSV Based 3-D Integrated Circuits  

E-print Network

Characterization and Modeling of TSV Based 3-D Integrated Circuits Speaker: Prof. Ioannis Savidis's research interests include emerging integrated circuit technologies, as well as analysis, modeling) based 3-D technologies. My work on the electrical modeling of TSVs culminated in the development

89

OPTICAL COMPONENT MODELLING AND CIRCUIT SIMULATION Laurent Guilloton1  

E-print Network

OPTICAL COMPONENT MODELLING AND CIRCUIT SIMULATION Laurent Guilloton1 , Smaïl Tedjini1 , Tan interferometer sensor. KEYWORD Optical circuit, simulation tool, modelling, S-matrix. ABSTRACT INTRODUCTION This communication introduces the modelling of optical and optoelectronic components and the simulation of optical

Paris-Sud XI, Université de

90

Resistive companion battery modeling for electric circuit simulations , R. Dougalb  

E-print Network

Resistive companion battery modeling for electric circuit simulations B. Wua , R. Dougalb , R reserved. Keywords: Battery modeling; Battery simulation; Electric circuit simulation; Resistive companion 2000; accepted 27 August 2000 Abstract Resistive companion (RC) modeling is an easy-to-use approach

91

Lumped circuit model for transient arc discharges  

SciTech Connect

Electrical breakdown of highly charged insulating systems can result in an arc discharge, i.e., a sudden, intense pulse of current. We model such arcs by a simple circuit: the discharge of a capacitor C (related to the initial charge reservoir) through a series inductor L and resistor R. For R = V*/chemically bondI/sub a/chemically bond, where V* is a positive constant and I/sub a/ is the arc current, an essentially arbitrary dependence for L = L(I/sub a/), a constant capacitance, and a circuit starting voltage V/sub 0/, we establish four remarkable results for the subsequent arc discharge: (1) no discharge occurs at all unless chemically bondV/sub 0/chemically bond>V*; (2) if n is the largest non-negative integer for which chemically bondV/sub 0/chemically bondgreater than or equal to(2n+1)V*, then the arc current will reverse sign precisely n times and will decline in amplitude by 2V* at each extreme; (3) the discharge stops abruptly at a final voltage V/sub f/ = (-1)/sup n//sup +1/(V/sub 0/-(n+1)2V* sgn V/sub 0/); (4) maxima and minima in I/sub a/ occur at voltages V = +- V*. Results (1) and (3) provide the threshold condition and finite final potential necessary for any realistic arc discharge theory, while result (2) suggests an experiment to look for a finite number of current oscillations in a highly driven arc. Result (4) suggests an experimental method for determining V*.

Robiscoe, R.T.; Kadish, A.; Maier II, W.B.

1988-11-01

92

Short-circuit current model of organic solar cells  

NASA Astrophysics Data System (ADS)

A physical model is presented for short-circuit current of organic solar cells based on the flow of both majority and minority carriers. According to the proposed model, the temperature, free carrier generation rate, light intensity, donor and acceptor dopant concentration dependences of short-circuit current can be well described. Good agreement between the calculated results and experimental data is found.

Lu, Nianduan; Li, Ling; Sun, Pengxiao; Liu, Ming

2014-10-01

93

Gamma and Theta Rhythms in Biophysical Models of Hippocampal Circuits  

E-print Network

Gamma and Theta Rhythms in Biophysical Models of Hippocampal Circuits N. Kopell, C. B¨orgers, D. Pervouchine, P. Malerba, and A. Tort Introduction The neural circuits of the hippocampus are extremely complex. Nevertheless, reduced models can provide insight into aspects of the dynamics and associated function

Pervouchine, Dmitri D.

94

A Simple Model of Circuit Design  

E-print Network

A simple analog circuit designer has been implemented as a rule based system. The system can design voltage followers. Miller integrators, and bootstrap ramp generators from functional descriptions of what these ...

Roylance, Gerald

1980-05-01

95

CMOS Interface Circuits for Spin Tunneling Junction Based Magnetic Random Access Memories  

SciTech Connect

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.

Ganesh Saripalli

2002-12-31

96

Low-voltage fluxgate magnetic current sensor interface circuit with digital output for portable applications  

Microsoft Academic Search

In this paper we present a complete low-voltage, low-power and high linearity CMOS interface circuit for fluxgate magnetic sensors for current measurement applications. The integrated circuit provides the correct excitation signal to the fluxgate sensors and reads-out the sensor signals from the sensing coils. The proposed circuit allows us to deal with sensors featuring different values of the excitation coil

M. Ferri; A. Surano; A. Rossini; P. Malcovati; E. Dallago; A. Baschirottoy

2009-01-01

97

Eddy-current Type Proximity Sensor with Closed Magnetic Circuit Geometry  

Microsoft Academic Search

Eddy-current type proximity sensor is a non-contact type sensing device to detect the approach of a conductor. This paper investigates electromagnetic properties of the proximity sensor with magnetic flux shield which has closed magnetic circuit geometry by FEM analysis and experiments. Although it has closed magnetic flux path, its sensing property is enhanced compared with the conventional proximity sensor

K. Koibuchi; K. Sawa; T. Honma; T. Hayashi; K. Ueda; H. Sasaki

2006-01-01

98

SET/RESET PULSE CIRCUITS FOR MAGNETIC SENSORS AN-201 Honeywell's line of magnetoresistive permalloy sensors  

E-print Network

SET/RESET PULSE CIRCUITS FOR MAGNETIC SENSORS AN-201 Honeywell's line of magnetoresistive permalloy sensors are sensitive to magnetic fields less than 100 µgauss in a ±2 gauss range. In order to achieve, or flip, the polarity of film magnetization, thus changing the sensor characteristics. Following

Kleinfeld, David

99

Permanent magnets models and losses in 2D FEM simulation of electrical machines  

Microsoft Academic Search

This paper presents different methods to model permanent magnet materials within the 2D finite element simulation of electrical machines and discuss them. The modeling deals with both the material magnetic properties and the circuit equations related to different parts of the machine. The emphasis is on modeling permanent magnets as part of the rotor electrical circuit. The methods presented are

Anouar Belahcen; Antero Arkkio

2010-01-01

100

Compact equivalent circuit model for the skin effect  

Microsoft Academic Search

Rules for determining a compact circuit model consisting of four resistors and three inductors to accurately predict the skin effect have been developed. The circuit is easily constructed from the geometry, producing a response that matches exact results over a frequency range from dc to very high frequencies

S. Kim; D. P. Neikirk

1996-01-01

101

Temperature dependent equivalent circuit of a magnetic-shield type SFCL  

Microsoft Academic Search

In order to investigate the reciprocal interaction between a SFCL and the Power System an equivalent circuit of the device needs to be introduced in a power system simulator. In this paper the equivalent circuit of a magnetic shield type SFCL, consisting of two coupled electric and thermal networks, is obtained starting from the integral formulation of the coupled electromagnetic-thermal

Massimo Fabbri; Antonio Morandi; Francesco Negrini; Pier Luigi Ribani

2005-01-01

102

Transformation of quantum photonic circuit models by term rewriting  

E-print Network

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).

Gopal Sarma; Ryan Hamerly; Nikolas Tezak; Dmitri S. Pavlichin; Hideo Mabuchi

2012-06-06

103

Three Dimensional Circuit Oriented Electromagnetic Modeling for VLSI Interconnects  

Microsoft Academic Search

A general approach for modeling 3-D layout geometries is presented. In particular, the partial-element equivalent circuit (PEEC) technique has been used successfully to model interconnect structures for chips and packages. The technique, which is circuit based, permits the electrical modeling of arbitrary 3-D geometries and allows 3-D transmission line properties to be analyzed. Recently, the technique has been extended to

Hansruedi Heeb; Albert E. Ruehli; J. Eric Bracken; Ronald A. Rohrer

1992-01-01

104

An Evolutionary Approach for Modeling the Equivalent Circuit for Electrochemical Impedance Spectroscopy  

E-print Network

An Evolutionary Approach for Modeling the Equivalent Circuit for Electrochemical Impedance to build the equivalent circuit model for electrochemical impedance spectroscopy. It works by using the interpretation of electrochemical impedance data includes three steps. First an equivalent circuit model

Fernandez, Thomas

105

MODELING AND VISUALIZATION OF SYNTHETIC GENETIC CIRCUITS  

E-print Network

. INTRODUCTION In 1977 a group of researchers managed to modify the DNA of the E. coli bacteria and were able to make it to produce the human hormone somatostatin [1]. Since that time genetic engineers have leveraged on Visualization of Genetic Circuits will give an overview on the use and effectiveness of the new visualization

Myers, Chris J.

106

A Linear Circuit Model For Social Influence Analysis  

E-print Network

Understanding the behaviors of information propagation is essential for the effective exploitation of social influence in social networks. However, few existing influence models are both tractable and efficient for describing the information propagation process and quantitatively measuring social influence. To this end, in this paper, we develop a linear social influence model, named Circuit due to its close relation to the circuit network. Based on the predefined four axioms of social influence, we first demonstrate that our model can efficiently measure the influence strength between any pair of nodes. Along this line, an upper bound of the node(s)' influence is identified for potential use, e.g., reducing the search space. Furthermore, we provide the physical implication of the Circuit model and also a deep analysis of its relationships with the existing methods, such as PageRank. Then, we propose that the Circuit model provides a natural solution to the problems of computing each single node's authority a...

Xiang, Biao; Liu, Qi; Xiong, Hui

2012-01-01

107

Note on homological modeling of the electric circuits  

E-print Network

Based on a simple example, it is explained how the homological analysis may be applied for modeling of the electric circuits. The homological branch, mesh and nodal analyses are presented. Geometrical interpretations are given.

Eugen Paal; Märt Umbleja

2014-06-16

108

Real Time Models of the Asynchronous Circuits: The Delay Theory  

E-print Network

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.

Serban E. Vlad

2004-12-17

109

Note on homological modeling of the electric circuits  

NASA Astrophysics Data System (ADS)

Based on a simple example, it is explained how the homological analysis may be used for modeling of the electric circuits. The homological branch, mesh and nodal analyses are presented. Geometrical interpretations are given.

Paal, E.; Umbleja, M.

2014-09-01

110

A statistical MOSFET modeling method for CMOS integrated circuit simulation  

E-print Network

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...

Chen, Jian

2012-06-07

111

Equivalent circuit models for resonant and PWM switches  

Microsoft Academic Search

The nonlinear switching mechanism in pulsewidth-modulated (PWM) and quasi-resonant converters is that of a three-terminal switching device which consists only of an active and a passive switch. An equivalent circuit model of this switching device describing the perturbations in the average terminal voltages and current is obtained. Through the use of this circuit model the analysis of pulsewidth modulated and

Vatche Vorperian; Richard Tymerski; F. C. Y. Lee

1989-01-01

112

Models of magnetism  

NSDL National Science Digital Library

This study investigates the mental models that people construct about magnetic phenomena. The project involved students, physics teachers, engineers, and practitioners. The researchers propose five models following a progression from simple description to a field model. Contains 28 references.

Borges, A. T.; Gilbert, John; Tecnico, Colegio

2006-05-23

113

Models of Magnetism.  

ERIC Educational Resources Information Center

Investigates the mental models that people construct about magnetic phenomena. Involves students, physics teachers, engineers, and practitioners. Proposes five models following a progression from simple description to a field model. Contains 28 references. (DDR)

Borges, A. Tarciso; Gilbert, John K.

1998-01-01

114

Characterization, modeling and optimization of fills and stress in semiconductor integrated circuits  

E-print Network

builds upon this modeling to improve circuit performance atmodeling of temperature dependences of SOI CMOS devices and circuitsModeling and analysis of self-heating in FinFET devices for improved circuit and

Topaloglu, Rasit Onur

2008-01-01

115

Multifunctionality and Robustness Trade-Offs in Model Genetic Circuits Olivier C. Martin* and Andreas Wagnery  

E-print Network

Multifunctionality and Robustness Trade-Offs in Model Genetic Circuits Olivier C. Martin. INTRODUCTION Most quantitative models of cellular circuits are severely lim- ited by many unknown biochemical. Examples involving networks include the transcriptional regulation circuits formed by Hox genes

Wagner, Andreas

116

Equivalent circuit modeling of hybrid electric vehicle drive train  

E-print Network

: Electromechanical model of the DC motor drive. . Figure 4. 4. 2: First equivalent circuit of the DC motor drive Figure 4. 4. 3: Final equivalent circuit of the DC motor drive. Figure 4. 4. 4: Synchronous machine stator circuit. Figure 4. 4. 5: Electromechanical... Vehicle (EV). It's a very elegant solution since it has been shown that the best source for traction is a constant power source, which is exactly what the electric motor is about. The excellent torque-speed characteristics of electric machines provide a...

Routex, Jean-Yves

2012-06-07

117

Computer modeling of batteries from non-linear circuit elements  

NASA Technical Reports Server (NTRS)

A simple non-linear circuit model for battery behavior is given. It is based on time-dependent features of the well-known PIN change storage diode, whose behavior is described by equations similar to those associated with electrochemical cells. The circuit simulation computer program ADVICE was used to predict non-linear response from a topological description of the battery analog built from advice components. By a reasonable choice of one set of parameters, the circuit accurately simulates a wide spectrum of measured non-linear battery responses to within a few millivolts.

Waaben, S.; Federico, J.; Moskowitz, I.

1983-01-01

118

From the Biot-Savart Law to Ampere's Magnetic Circuital Law via Synthetic Differential Geometry  

E-print Network

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.

Hirokazu Nishimura

2014-01-08

119

Circuit resonance energy: a key quantity that links energetic and magnetic criteria of aromaticity.  

PubMed

Energetic and magnetic criteria of aromaticity are different in nature and sometimes make different predictions as to the aromaticity of a polycyclic pi-system. Thus, some charged polycyclic pi-systems are aromatic but paratropic. We derived the individual circuit contributions to aromaticity from the magnetic response of a polycyclic pi-system and named them circuit resonance energies (CREs). Each CRE has the same sign and essentially the same magnitude as the corresponding cyclic conjugation energy (CCE) defined by Bosanac and Gutman. Such CREs were found to play a crucial role in associating the energetic criteria for determining the degree of aromaticity with the magnetic ones. We can now interpret both energetic and magnetic criteria of aromaticity consistently in terms of CREs. Ring-current diamagnetism proved to be the tendency of a cyclic pi-system to retain aromatic stabilization energy (ASE) at the level of individual circuits. PMID:16506765

Aihara, Jun-ichi

2006-03-01

120

SIMPEL: Circuit model for photonic spike processing laser neurons  

E-print Network

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.

Shastri, Bhavin J; Tait, Alexander N; Wu, Ben; Prucnal, Paul R

2014-01-01

121

Phase separation in random cluster models III: circuit regularity  

E-print Network

We study the droplet that results from conditioning the subcritical Fortuin-Kasteleyn planar random cluster model on the presence of an open circuit Gamma_0 encircling the origin and enclosing an area of at least (or exactly) n^2. In this paper, we prove that the resulting circuit is highly regular: we define a notion of a regeneration site in such a way that, for any such element v of Gamma_0, the circuit Gamma_0 cuts through the radial line segment through v only at v. We show that, provided that the conditioned circuit is centred at the origin in a natural sense, the set of regeneration sites reaches into all parts of the circuit, with maximal distance from one such site to the next being at most logarithmic in n with high probability. The result provides a flexible control on the conditioned circuit that permits the use of surgical techniques to bound its fluctuations, and, as such, it plays a crucial role in the derivation of bounds on the local fluctuation of the circuit carried out in arXiv:1001.1527 and arXiv:1001.1528.

Alan Hammond

2010-01-10

122

Improved Model Generation of AMS Circuits for Formal Verification  

E-print Network

Improved Model Generation of AMS Circuits for Formal Verification Dhanashree Kulkarni, Satish in the generation of these abstract models from simulation data. In particular, this paper focuses on modeling important to have efficient and reli- able methods. Systems can be validated using either simulation

Myers, Chris J.

123

Combination of Thermal Subsystems Modelled by Rapid Circuit Transformation  

E-print Network

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.

Y. C. Gerstenmaier; W. Kiffe; G. Wachutka

2008-01-07

124

Circuit Models of Nonlinear Inhibition The silicon models of auditory localization and pitch perception, presented  

E-print Network

38 Chapter 3 Circuit Models of Nonlinear Inhibition The silicon models of auditory localization of the computation. The circuit described in the chapter implements general nonlinear inhibition in its extreme form, known as winner-take-all. In addition to the projects in Chapters 4 and 5, the winner-take-all circuit

Lazzaro, John

125

Transient peak currents in permanent magnet synchronous motors for symmetrical short circuits  

Microsoft Academic Search

To enable constant-power areas with permanent magnet synchronous motors, flux weakening has to be applied. In that mode, the inverter protection measure, e.g. in case of overcurrent, is a crucial point, since the open-circuit induced terminal voltage may exceed the allowed inverter limit. That is why a symmetrical short circuit (SSC) is currently favoured as alternative protection measure. Though the

Michael Meyer; Joachim Böcker

2006-01-01

126

Sheath Equivalent Electrical Circuit Model for Transient Sheath Dynamics  

NASA Astrophysics Data System (ADS)

This work presents a new alternate understanding and interpretation of the observed ion implantation current profile in transient sheath experiments. Two time-scale structure of the observed ion implantation current profile is clearly noted in constant phase of applied pulse voltage at the electrode. But no complete and self-consistent model calculation for theoretical explanation is available as yet. We treat the positive (ion-rich) sheath as an equivalent electrical series LCR circuit and use Kirchoff’s law to arrive at a second order differential equation for theoretical description of the defined circuit. The Child law describes the expanding motion of transient sheath dynamics and monitors current in the circuit. Numerical solution of the defined driven circuit equation yields almost the same current profile as observed in the transient sheath experiments.

Deka, Utpal; Prakash, Ram; Sarma, Arun; Dwivedi, Chandra Bhushan

2004-05-01

127

An accurate RLGC circuit model for dual tapered TSV structure  

NASA Astrophysics Data System (ADS)

A fast RLGC circuit model with analytical expression is proposed for the dual tapered through-silicon via (TSV) structure in three-dimensional integrated circuits under different slope angles at the wide frequency region. By describing the electrical characteristics of the dual tapered TSV structure, the RLGC parameters are extracted based on the numerical integration method. The RLGC model includes metal resistance, metal inductance, substrate resistance, outer inductance with skin effect and eddy effect taken into account. The proposed analytical model is verified to be nearly as accurate as the Q3D extractor but more efficient.

Zhen, Wei; Xiaochun, Li; Junfa, Mao

2014-09-01

128

Impact of radial external magnetic field on plasma deformation during contact opening in SF6 circuit breakers  

NASA Astrophysics Data System (ADS)

A three-dimensional (3D) transient model is developed to investigate plasma current deformation driven by internal and external magnetic fields and their influences on arc stability in a circuit breaker. The 3D 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 the magnetic field induced by the current flowing through the arc column is calculated by the magnetic vector potential equation. The applied external field imposes a rotational electromagnetic force on the arc and influences the plasma current deformation, which is discussed in this paper. In SF6 circuit breakers when gas interacts with the arc column, the fundamental equations such as Ampere's law, Ohm's law, turbulence model, transport equations of mass, momentum, and energy of plasma flow have to be coupled for analysing the phenomenon. The coupled interactions between the arc and the plasma flow are described within the framework of magnetohydrodynamic equations in conjunction with a K-? turbulence model. Simulations are focused on sausage and kink instabilities in the plasma (these phenomena are related to the electromagnetic field distribution and define the plasma deformations). The 3D simulation reveals the relation between plasma current deformation and instability phenomena, which affects the arc stability during the operation. Plasma current deformation is a consequence of coupling between electromagnetic forces (resulting from internal and radial external magnetic fields) and the plasma flow that are described in the simulations.

Abbasi, V.; Gholami, A.; Niayesh, K.

2012-10-01

129

Magnetic Bar Field Model  

NSDL National Science Digital Library

The EJS Magnetic Bar Field Model shows the field of a bar magnet and has a movable compass that reports the magnetic field values. The bar magnet model is built by placing a group of magnetic dipoles along the bar magnet. You can modify this simulation if you have Ejs installed by right-clicking within the plot and selecting âOpen Ejs Modelâ from the pop-up menu item. The Magnetic Bar Field model was created using the Easy Java Simulations (Ejs) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_em_MagneticBarField.jar file will run the program if Java is installed. Ejs is a part of the Open Source Physics Project and is designed to make it easier to access, modify, and generate computer models. Additional Ejs models are available. They can be found by searching ComPADRE for Open Source Physics, OSP, or Ejs.

Christian, Wolfgang; Franciscouembre; Cox, Anne

2009-09-18

130

Risk Based Maintenance Optimization using Probabilistic Maintenance Quantification Models of Circuit Breaker  

E-print Network

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...

Natti, Satish

2010-01-14

131

A simple MOSFET model for circuit analysis  

Microsoft Academic Search

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

Takayasu Sakurai; A. Richard Newton

1991-01-01

132

Timing model extraction for sequential circuits considering process variations  

Microsoft Academic Search

As semiconductor devices continue to scale down, process variations become more relevant for circuit design. Facing such variations, statistical static timing analysis is introduced to model variations more accurately so that the pessimism in traditional worst case timing analysis is reduced. Because all delays are modeled using correlated random variables, most statistical timing methods are much slower than corner based

Bing Li; Ning Chen; Ulf Schlichtmann

2009-01-01

133

Qubit logic modeling by electronic circuits and electromagnetic signals  

E-print Network

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.

G. A. Kouzaev

2001-08-02

134

Modeling of opto-electronics in complex photonic integrated circuits  

NASA Astrophysics Data System (ADS)

This work addresses a versatile modeling of complex photonic integrated circuits (PICs) including optical and electrical sub-elements. We introduce a new family of electrical elements, together with a novel electronic-photonic co-design, that complements current capabilities of photonic circuit simulators. This is illustrated with the modeling of complex electric circuits contained in photonic devices. Simulations of the interaction between electrical and optical parts allow the analysis of unwanted effects such as reflections due to impedance mismatching, as well as the optimization of the PIC as a whole. We illustrate the functionalities of our approach through application examples. As a use case, we present a model of the electrical driver for a monolithically-integrated InP transmitter developed in frame of the European research project MIRTHE and the analysis of the driver and the EA-Modulator interplay.

Arellano, C.; Mingaleev, S.; Koltchanov, I.; Richter, A.

2014-03-01

135

BATTERIES AND BULBS, BOOK 1, CIRCUITS I, AN EARLY EXPLORATION OF ELECTRICAL CIRCUITS AND MAGNETS.  

ERIC Educational Resources Information Center

THIS TRIAL EDITION OF A TEACHING GUIDE IS INTENDED TO PROVIDE RESOURCE MATERIAL FOR AN INTRODUCTORY STUDY OF ELECTRICITY AND MAGNETISM, AND IS NUMBER ONE OF A SERIES OF FOUR. IT IS SUITABLE FOR USE AT VARIOUS LEVELS FROM GRADES 2-10. THE FOUR VOLUMES PRESENT ACTIVITIES SUFFICIENT FOR A PROGRAM OF FROM 5 TO 40 WEEKS, DEPENDING UPON EXTENT OF USE…

1966

136

Extraction of Piecewise-Linear Analog Circuit Models from Trained Neural Networks using Hidden Neuron Clustering  

E-print Network

Extraction of Piecewise-Linear Analog Circuit Models from Trained Neural Networks using Hidden the technique for an OTA circuit for which models for gain and bandwidth were automatically generated modeling method that can be efficiently used for both circuit simulation and synthesis. Analog circuit

Doboli, Simona

137

Delay modeling and glitch estimation for CMOS circuits  

E-print Network

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...

Shiau, Yan-Chyuan

2012-06-07

138

Modeling of single-event upset in bipolar integrated circuits  

NASA Technical Reports Server (NTRS)

The results of work done on the quantitative characterization of single-event upset (SEU) in bipolar random-access memories (RAMs) have been obtained through computer simulation of SEU in RAM cells that contain circuit models for bipolar transistors. The models include current generators that emulate the charge collected from ion tracks. The computer simulation results are compared with test data obtained from a RAM in a bipolar microprocessor chip. This methodology is applicable to other bipolar integrated circuit constructions in addition to RAM cells.

Zoutendyk, J. A.

1983-01-01

139

Quantum Magnetism Analysis Model  

NSDL National Science Digital Library

The Quantum Magnetism Analysis Model was created to help students as well as researchers who are studying magnetism. It provides a very simple interface for defining (theoretical) quantum spin models; sliders are automatically created to vary the parameters in the models; and several plots are automatically created to visualize the results. Within the program, several measured (experimental) data sets are included for a variety of real molecules. These provide the opportunity to experience the modeling process by varying the parameters in the model and exploring how the simulated results compare to the measured data. The interactions between neighboring quantum magnetic moments ("spins") are modeled using the Heisenberg model; calculations are carried out by numerically diagonalizing the matrix representation of the Heisenberg Hamiltonian; and plots display the energy spectrum, magnetization, and magnetic susceptibility as a function of temperature and magnetic field. This simulation is a "Fully Integrated Tool for Magnetic Analysis in Research & Teaching," so we also refer to it with the acronym "FIT-MART". FIT-MART was developed using the Easy Java Simulations (EJS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking ejs_fitmart.jar file will run the package if Java is installed. In future versions of this simulation, curricular materials will be included to help students to learn about magnetism, and automated fitting routines will be included to help researchers quickly and easily model experimental data. FIT-MART was developed using the Easy Java Simulations (EJS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking ejs_fitmart.jar file will run the package if Java is installed.

Engelhardt, Larry; Garland, Chad; Rainey, Cameron; Freeman, Austin

2012-07-27

140

A circuit simulation model for high-frequency power MOSFETs  

Microsoft Academic Search

A circuit simulation model suitable for modeling the static and dynamic switching characteristics of high-frequency power MOSFETs is reported. The model parameters were obtained from physical device layout, silicon doping, and measured electrical characteristics of power MOSFETs. Accurate voltage dependencies of the interelectrode capacitances were obtained from extensive two-dimensional device simulations. The voltage dependence of gate-drain capacitance was modeled using

Krishna Shenai

1991-01-01

141

Proximity detector circuits: an attractive alternative to tunnel diode oscillators for contactless measurements in pulsed magnetic fields  

SciTech Connect

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.

Altarawneh, Moaz M [Los Alamos National Laboratory; Mielke, Charles H [Los Alamos National Laboratory

2009-01-01

142

Distributed-element circuit model of edge magnetoplasmon transport  

NASA Astrophysics Data System (ADS)

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.

Hashisaka, Masayuki; Kamata, Hiroshi; Kumada, Norio; Washio, Kazuhisa; Murata, Ryuji; Muraki, Koji; Fujisawa, Toshimasa

2013-12-01

143

Yield learning model for integrated circuit package  

E-print Network

assemblies has been developed and implemented. Sensitivity analysis was performed to isolate the factors that affected yield learning the most. The yield model was developed after performing case studies on the Tape Carrier Package at Intel Corporation...

Balasubramaniam, Gaurishankar

2012-06-07

144

Noise modeling for RF CMOS circuit simulation  

Microsoft Academic Search

The RF noise in 0.18-?m CMOS technology has been measured and modeled. In contrast to some other groups, we find only a moderate enhancement of the drain current noise for short-channel MOSFETs. The gate current noise on the other hand is more significantly enhanced, which is explained by the effects of the gate resistance. The experimental results are modeled with

Andries J. Scholten; Luuk F. Tiemeijer; Ronald van Langevelde; Ramon J. Havens; A. T. A. Zegers-van Duijnhoven; Vincent C. Venezia

2003-01-01

145

Generalized Partial Element Equivalent Circuit (PEEC) Modeling With Radiation Effect  

Microsoft Academic Search

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

Lap K. Yeung; Ke-Li Wu

2011-01-01

146

Modeling an optical magnetometer with electronic circuits Analysis and optimization  

E-print Network

Modeling an optical magnetometer with electronic circuits � Analysis and optimization Przemyslaw, University of California at Berkeley Berkeley, California 94720-7300, USA ABSTRACT: Optical magnetometers are typically obtained for ultra-low-field measurements, a group of optical magnetometers allows the detection

147

Invited Paper An Integrated-Circuit Switched-Capacitor Model  

E-print Network

, and left ventricle. The contractions in each of the four chambers lead to pressure differences that cause delays between the various signals may be useful in monitoring parameters related to blood pressure via circuit model of the heart. The chip may be useful in low-power body sensor networks that use analysis

Sarpeshkar, Rahul

148

Real time railway traffic management modeling track-circuits  

E-print Network

Real time railway traffic management modeling track-circuits Paola Pellegrini, Grégory Marlière.rodriguez@ifsttar.fr Abstract The real time railway traffic management seeks for the train routing and scheduling that minimize tested the proposed formulation on real perturbation instances representing traffic in a control area

Paris-Sud XI, Université de

149

Pharmacokinetic model of closed-circuit inhalation anesthesia  

Microsoft Academic Search

A mathematical model consisting of six well-mixed tissue compartments was used for prediction of an anesthetic dose rate designed to maintain a constant arterial halothane concentration during closed-circuit anesthesia with halothane and nitrous oxide. Metabolism of anesthetics was not considered; they were regarded as inert. Calculated rates of vapor were administered to provide a predicted level of anesthesia in 20

I. S. Gouldberg; J. W. Mostert; E. F. Lanzl; H. J. Lowe

1978-01-01

150

Monte Carlo Reliability Model for Microwave Monolithic Integrated Circuits  

E-print Network

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

Rubloff, Gary W.

151

CIRCUIT MODELS OF SENSORY TRANSDUCTION IN THE COCHLEA  

Microsoft Academic Search

this paper, we describe thearchitecture and operation of an integrated circuit that models, to a limiteddegree, the evoked responses of the auditory nerve. The chip receives as inputa time-varying voltage corresponding to sound input, and computes outputsthat correspond to the responses of individual auditory-nerve fibers. The chipmodels the structure as well as the function of the cochlea; all subcircuits in

John Lazzaro; Carver Mead

1989-01-01

152

A Wide Bandwidth Model for the Electrical Impedance of Magnetic BearingS  

NASA Technical Reports Server (NTRS)

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.

Meeker, David C.; Maslen, Eric H.; Noh, Myounggyu D.

1996-01-01

153

BATTERIES AND BULBS, BOOK 2, CIRCUITS AND MAGNETS.  

ERIC Educational Resources Information Center

THIS TRIAL EDITION OF A TEACHER'S GUIDE, BOOK TWO IN A SERIES OF FOUR, IS INTENDED TO PROVIDE RESOURCE MATERIAL FOR AN INTRODUCTORY STUDY OF ELECTRICITY AND MAGNETISM. IT IS SUITABLE FOR ADAPTION TO VARIOUS LEVELS FROM GRADES 2-10. USED IN CONJUNCTION WITH THE OTHER VOLUMES, IT PROVIDES MATERIAL FOR A PROGRAM OF FROM 5 TO 40 WEEKS, DEPENDING ON…

1966

154

Precision of an eddy current sensor with magnetic circuit losses  

Microsoft Academic Search

This paper describes an inductive magnetic sensor for the translation measurement of a metal sheet during the drop-stamping process. This electromagnetic sensor consists of a cast-iron core coil sensor. The classical coil system approach does not include the eddy current effect in the transducer core. The main feature of this paper is to define the eddy current effect on the

P. Reghem; E. Destobbeleer; T. Derrey; L. Protin

1994-01-01

155

Equivalent circuit modeling of losses and dispersion in single and coupled lines for microwave and millimeter-wave integrated circuits  

Microsoft Academic Search

Losses and dispersion in open inhomogeneous guided-wave structures such as microstrips and other planar structures at microwave and millimeter-wave frequencies and in MMICs (monolithic microwave integrated circuits) have been modeled with circuits consisting of ideal lumped elements and lossless TEM (transverse electromagnetic) lines. It is shown that, given a propagation structure for which numerical techniques to compute the propagation characteristics

Vijai K. Tripathi; Achim Hill

1988-01-01

156

Model of a chopper-driven magnetic actuator in an electrohydraulic system  

Microsoft Academic Search

An electrohydraulic system is modeled using a version of the electric circuit analysis program SPICE. The input is a typical DC voltage source and the output is a hydraulic pressure and flow. Analogies between hydraulic circuits and electrical circuits are used, along with nonlinear tables obtained by electromagnetic finite element analysis of a magnetic actuator that operates a proportional hydraulic

John R. Brauer

2001-01-01

157

Physics based lumped element circuit model for nanosecond pulsed dielectric barrier discharges  

E-print Network

Physics based lumped element circuit model for nanosecond pulsed dielectric barrier discharges, efficient circuit element models have been introduced to approximate the complex processes within plasmas into the model. II. LUMPED ELEMENT CIRCUIT MODEL One of the primary assumptions in creating this model

Roy, Subrata

158

Shape-preserving response prediction for microwave circuit modeling  

Microsoft Academic Search

A new and simple surrogate modeling technique for microwave devices is presented. Our method exploits a recently introduced shape-preserving response prediction procedure that allows us to estimate the response (e.g., S-parameters over certain frequency range) of the computationally expensive microwave structure by examining the response of the computationally cheap (e.g., circuit equivalent) model of the structure. It is demonstrated that

Slawomir Koziel

2010-01-01

159

Compact modeling of nonlinear distortion in analog communication circuits  

Microsoft Academic Search

The design of analog front-ends of digital telecommunication transceivers requires simulations at the architectural level. The nonlinear nature of the analog front-end blocks is a complication for their modeling at the architectural level, especially when the nonlinear behavior is frequency dependent. This paper describes a method to derive a bottom-up model of nonlinear analog continuous-time circuits used in communication systems.

P. Wambacq; P. Dobrovolny; S. Donnay; M. Engels; I. Bolsens

2000-01-01

160

Example of Lumped Parameter Modeling of a Quantum Optics Circuit  

E-print Network

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.

Paul J. Werbos

2013-09-23

161

IBMG: Interpretable Behavioral Model Generator for Nonlinear Analog Circuits via Canonical Form  

E-print Network

IBMG: Interpretable Behavioral Model Generator for Nonlinear Analog Circuits via Canonical Form models of nonlinear analog circuits, with the special distinction that it generates models-domain behavior of the circuit being modeled. The approach uses genetic programming (GP), which evolves functions

Fernandez, Thomas

162

Quaternary Addition Circuits Based on SUSLOC Voltage-Mode Cells and Modeling with SystemVerilog  

E-print Network

Quaternary Addition Circuits Based on SUSLOC Voltage-Mode Cells and Modeling with System] are modeled and used for our adder circuit structures. Several different adder configurations are designed offers efficient modeling capabilities to model and simulate large MVL circuits [3]. The quaternary

Thornton, Mitchell

163

Application of Least Squares MPE technique in the reduced order modeling of electrical circuits  

E-print Network

Application of Least Squares MPE technique in the reduced order modeling of electrical circuits an unsolvable reduced order model. This means that a model of an electrical circuit can become ill processes is also applied to the least-square reduced order model of the electrical circuit. The least

Eindhoven, Technische Universiteit

164

Circuit-Level Modeling for Concurrent Testing of Operational Defects due to Gate Oxide Breakdown  

E-print Network

Circuit-Level Modeling for Concurrent Testing of Operational Defects due to Gate Oxide Breakdown previous work in fault modeling, and it focuses on existing circuit-level fault modeling and the recent circuit-level consideration. Our contributions in these two areas are the following: · Fault modeling

Paris-Sud XI, Université de

165

An alternative approach to model the Internal Activity of integrated circuits.  

E-print Network

An alternative approach to model the Internal Activity of integrated circuits. N. Berbel, R Toulouse Toulouse, France Abstract--This paper deals with the EMC modeling of integrated circuits and the standardized model IEC 62433-2 (Integrated Circuit Emission Model ­ Conducted Emission [1]). This standardized

Paris-Sud XI, Université de

166

A pharmacokinetic model of closed-circuit inhalation anesthesia  

Microsoft Academic Search

A mathematical model consisting of six well-mixed tissue compartments was used for prediction of an anesthetic dose rate designed\\u000a to maintain a constant arterial halothane concentration during closed-circuit anesthesia with halothane and nitrous oxide.\\u000a Metabolism of anesthetics was not considered they were regarded as inert. Calculated rates of vapor were administered to provide\\u000a a predicted level of anesthesia in 20

Irwin S. Goldberg; Jacobus W. Mostert; Elisabeth F. Lanzl; HARRY J. LOWEw

1978-01-01

167

The transverse wakefield calculated by double circuit model  

E-print Network

X-band accelerator for multi-bunches has been a new way to produce high luminosity and energy efficiency bunches. As the smaller size and multi-bunches, the wakefield is more severe in X-band accelerator, unless some means of strongly suppressing of the transverse wakefield is adopted in the design of the accelerating structure. To calculate the transverse wakefield of the structure, wakefield calculated through the double circuit model has been demonstrated and its application in the structure designed.

Bin, Yang Xiong

2014-01-01

168

Integrated circuit substrate coupling models based on Voronoi tessellation  

Microsoft Academic Search

We present a modeling technique for assessing the impact of substrate-coupled switching noise in CMOS mixed-signal circuits. Since the magnitude of the noise problem is a function of the relative proximity of noisy and sensitive devices, design aids are required which can incorporate the switching noise effects at the post-layout phase of design verification. In our approach, SPICE-compatible lumped element

Ivan L. Wemple; Andrew T. Yang

1995-01-01

169

Continuum based modeling of silicon integrated circuit processing: An object oriented approach  

E-print Network

Continuum based modeling of silicon integrated circuit processing: An object oriented approach Mark based integrated circuit process modeling is the dominant tool used to investigate and understand in- tegrated circuit (IC) development. This paper describes the commonly used models for implantation, diusion

Florida, University of

170

The PABTEC Algorithm for Passivity-Preserving Model Reduction of Circuit Equations  

E-print Network

The PABTEC Algorithm for Passivity-Preserving Model Reduction of Circuit Equations Tatjana Stykel for new modelling techniques and simulation algorithms for circuit design that make use of the structure and properties of the underlying problem. The numerical treatment of complex circuit models containing hundreds

Reis, Timo

171

Partial Element Equivalent Circuit (PEEC) models for on-chip passives and interconnects  

E-print Network

Partial Element Equivalent Circuit (PEEC) models for on-chip passives and interconnects Menno E model can be formulated as an equivalent circuit. We have conducted some simple experiments to see of the chips circuit. To reduce the size of the EM model, we can use an integral equation formulation

Eindhoven, Technische Universiteit

172

Formal Verification of Digital Circuits Using Symbolic Ternary System Models \\Lambda  

E-print Network

Formal Verification of Digital Circuits Using Symbolic Ternary System Models \\Lambda Randal E. By making this extension, we can model a wider range of circuit phenomena. We can also efficiently verify a ternary system model. The desired behavior of the circuit is expressed as assertions in a notation using

Bryant, Randal E.

173

A picosecond Josephson junction model for circuit simulation A. De Lustrac, P. Crozat and R. Adde  

E-print Network

319 A picosecond Josephson junction model for circuit simulation A. De Lustrac, P. Crozat and R with standard circuit simulators (SPICE, ASTEC). It allows usually an efficient modelling of Josephson tunnel of such fast Josephson circuits requires a junction model taking into account with a reasonable accuracy

Paris-Sud XI, Université de

174

Model Order Reduction of Large Circuits Using Balanced Truncation Payam Rabiei and Massoud Pedram  

E-print Network

1 Model Order Reduction of Large Circuits Using Balanced Truncation Payam Rabiei and Massoud Pedram is introduced for model order reduction of large circuits extracted from layout. The algorithm, which is based of the circuit. Since the frequency is high, the interconnections should be modeled as distributed elements

Pedram, Massoud

175

A two-port analogous circuit and SPICE model for Salmon's family of acoustic horns  

E-print Network

A two-port analogous circuit and SPICE model for Salmon's family of acoustic horns W. Marshall-port electroacoustic analogous circuit model for finite-length acoustic horns belonging to Salmon's family of horns of the circuit model for use with the PSpice simulator software is given. Example simulations are presented which

Leach Jr.,W. Marshall

176

Modeling of Large Scale RF-MEMS Circuits Using Efficient Time-Domain Techniques  

E-print Network

Modeling of Large Scale RF-MEMS Circuits Using Efficient Time-Domain Techniques N. Bushyager, E-domain (FDTD) electromagnetic modeling technique to model circuit elements that include MEMS devices difficult due to the lack of tools capable of simulating both MEMS devices and their surrounding circuits

Tentzeris, Manos

177

On the models for asynchronous circuit behaviour with OR causality A. Yakovleva  

E-print Network

On the models for asynchronous circuit behaviour with OR causality A. Yakovleva M. Kishinevskyb A and Change Diagrams provide adequate modelling and circuit synthesis tools for the various OR causality types of examples demonstrate the usefulness of this model in the synthesis of asynchronous control circuits

Newcastle upon Tyne, University of

178

Development of a Lumped Element Circuit Model for Approximation of Nanosecond Pulsed Dielectric  

E-print Network

Development of a Lumped Element Circuit Model for Approximation of Nanosecond Pulsed Dielectric This work presents a circuit model for calculating the total energy dissipated into neu- tral species circuit model is de- veloped for both homogeneous regions based on a combination of a resistor, capacitors

Roy, Subrata

179

Lightning Modelling: From 3D to Circuit Approach  

NASA Astrophysics Data System (ADS)

The topic of this study is electromagnetic environment and electromagnetic interferences (EMI) effects, specifically the modelling of lightning indirect effects [1] on aircraft electrical systems present on deported and highly exposed equipments, such as nose landing gear (NLG) and nacelle, through a circuit approach. The main goal of the presented work, funded by a French national project: PREFACE, is to propose a simple equivalent electrical circuit to represent a geometrical structure, taking into account mutual, self inductances, and resistances, which play a fundamental role in the lightning current distribution. Then this model is intended to be coupled to a functional one, describing a power train chain composed of: a converter, a shielded power harness and a motor or a set of resistors used as a load for the converter. The novelty here, is to provide a pre-sizing qualitative approach allowing playing on integration in pre-design phases. This tool intends to offer a user-friendly way for replying rapidly to calls for tender, taking into account the lightning constraints. Two cases are analysed: first, a NLG that is composed of tubular pieces that can be easily approximated by equivalent cylindrical straight conductors. Therefore, passive R, L, M elements of the structure can be extracted through analytical engineer formulas such as those implemented in the partial element equivalent circuit (PEEC) [2] technique. Second, the same approach is intended to be applied on an electrical de-icing nacelle sub-system.

Moussa, H.; Abdi, M.; Issac, F.; Prost, D.

2012-05-01

180

Phase-Boundary of a Cubic Superconducting Circuit in a Magnetic-Field of Arbitrary Magnitude and Direction  

E-print Network

An exact analytic expression for the mean-field phase boundary T(c)(H) of a cubic superconducting circuit in an arbitrary external-magnetic-field vector H is derived. The phase boundary of this circuit is shown to depend in a complex and sensitive...

Hu, Chia-Ren; HUANG, CH.

1991-01-01

181

Characterization of Stator Winding Short-Circuit Faults in Interior Permanent-Magnet Motor-Drive Systems.  

E-print Network

??This thesis contains a comprehensive analysis of experimental data collected from a case-study interior permanent-magnet electric machine experiencing winding short-circuit faults of varying severity. The… (more)

Strandt, Andrew

2013-01-01

182

Measured turbulent mixing in a small-scale circuit breaker model  

E-print Network

Measured turbulent mixing in a small-scale circuit breaker model N. P. T. Basse,* R. Bini, and M, we constructed a simple small-scale model of a gas circuit breaker. The heating volume was a two circuit breakers depends on the temperature distribution of hot gas or plasma from the arc zone mixed

Basse, Nils Plesner

183

Improved Delay and Current Models for Estimating Maximum Currents in CMOS VLSI Circuits  

E-print Network

Improved Delay and Current Models for Estimating Maximum Currents in CMOS VLSI Circuits Harish in the circuit. In 1 , the algorithm was demonstrated for simple gate delay and current models. In this paper, we Abstract Excessive voltage drops in power and ground P&G buses of CMOS VLSI circuits can severely degrade

Najm, Farid N.

184

Improved Delay and Current Models for Estimating Maximum Currents in CMOS VLSI Circuits  

E-print Network

Improved Delay and Current Models for Estimating Maximum Currents in CMOS VLSI Circuits Harish in the circuit. In [1], the algorithm was demonstrated for simple gate delay and current models. In this paper Abstract Excessive voltage drops in power and ground (P&G) buses of CMOS VLSI circuits can severely degrade

Najm, Farid N.

185

Data Mining Approaches for Modeling Complex Electronic Circuit Design Activities  

SciTech Connect

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.

Kwon, Yongjin [Ajou University, Suwon, South Korea; Omitaomu, Olufemi A [ORNL; Wang, Gi-Nam [Ajou University, Suwon, South Korea

2008-01-01

186

Solar Array Panel Equivalent Circuit Model for Transient Analysis of Electrostatic Discharge  

NASA Astrophysics Data System (ADS)

The increase of spacecraft power increases the risk of electrostatic discharges on solar array panel. The discharge current may induce surge voltage and current at the power control electronics or the spacecraft payload. In order to study the surge effect via analysis, we need an equivalent circuit model of spacecraft, especially solar paddle circuit. We make an equivalent circuit of solar array string by a combination of simple LCR circuit, suitable for simulation via an electronic circuit simulation software (SPICE). The circuit is verified against the impedance over the wide range up to several megahertz. The circuit response to a pulse waveform is also verified. Surge voltage generated by a flashover current extending to 3.4m x 2.1m is studied using the equivalent circuit of a solar paddle. The flashover propagation is modeled by turning on parallel switches with time delays. Surge voltage of 20V or higher is expected to occur across the spacecraft load.

Maeshima, Junji; Cho, Mengu

187

A DEVS-based Modeling and Behavioral Fault Simulator for RT-Level Digital Circuits  

E-print Network

A DEVS-based Modeling and Behavioral Fault Simulator for RT-Level Digital Circuits Capocchi Laurent The domain of fault simulation for digital circuits de- scribed at the RT-level is currently under heavy and the simulation of behavioral faults for digital circuits described in the VHDL language, using a dis- crete event

Boyer, Edmond

188

Circuit Based Quantification: Back to State Set Manipulation within Unbounded Model Checking  

E-print Network

Circuit Based Quantification: Back to State Set Manipulation within Unbounded Model Checking Informatica Turin, ITALY Abstract In this paper a non-canonical circuit-based state set rep- resentation equiva- lence checking and logic synthesis techniques, to the goal of compacting circuit based state set

Paris-Sud XI, Université de

189

Frequency-independent equivalent circuit model for microstrip open-end and gap discontinuities  

Microsoft Academic Search

The development of user friendly software for microwave integrated circuits will become possible with the adoption of lumped equivalent circuits for interconnect discontinuities. Frequency independent equivalent lumped circuit models are proposed in this paper, wherein resistors are introduced to account for radiation and surface wave losses at microstrip discontinuities. Simple algebraic expressions are obtained for the elements of lumped equivalent

Nicolaos G. Alexopoulos; Shih-Chang Wu

1994-01-01

190

Control of ball mill grinding circuit using model predictive control scheme  

Microsoft Academic Search

Ball mill grinding circuits are essentially multivariable systems with high interaction among process variables. Traditionally grinding circuits are controlled by detuned multi-loop PI controllers that minimize the effect of interaction among the control loops. Detuned controllers generally become sluggish and a close control of the circuit is not possible. Model Predictive Controllers (MPC) can handle such highly interacting multivariable systems

M. Ramasamy; S. S. Narayanan; Ch. D. P. Rao

2005-01-01

191

Model a Magnet  

NSDL National Science Digital Library

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.

192

Modeling and simulation of insulated-gate field-effect transistor switching circuits  

Microsoft Academic Search

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

HAROLD SHICHMAN; DAVID A. HODGES

1968-01-01

193

Practical modelling of permanent magnet synchronous machines with rare-earth magnets  

Microsoft Academic Search

In high-field machines employing rare-earth magnets the effect of saturation is significant, and therefore appropriate modification to the classic two-reaction theory has to be considered to achieve more accurate and realistic prediction of the machine performance. Two approaches are described for modelling the steady-state operation of permanent magnet synchronous machines from the two-reaction equivalent circuit which take into account the

F. B. Chaaban; P. H. Mellor; K. J. Binns

1990-01-01

194

Wideband passive multiport model order reduction and realization of RLCM circuits  

Microsoft Academic Search

This paper presents a novel compact passive modeling technique for high-performance RF passive and interconnect circuits modeled as high-order resistor-inductor-capacitor-mutual inductance circuits. The new method is based on a recently proposed general s-domain hierarchical modeling and analysis method and vector potential equivalent circuit model for self and mutual inductances. Theoretically, this paper shows that s-domain hierarchical reduction is equivalent to

Zhenyu Qi; Hao Yu; Pu Liu; Sheldon X.-D. Tan; Lei He

2006-01-01

195

Astrocyte regulation of sleep circuits: experimental and modeling perspectives  

PubMed Central

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 into global modulation of neuronal networks and behavior. We discuss these findings in the context of current conceptual models of sleep generation and function, each of which have historically focused on neural mechanisms. We highlight the implications and the challenges introduced by these results from a conceptual and computational perspective. We further provide modeling directions on how these data might extend our knowledge of astrocytic properties and sleep function. Given our evolving understanding of how local cellular activities during sleep lead to functional outcomes for the brain, further mechanistic and theoretical understanding of astrocytic contribution to these dynamics will undoubtedly be of great basic and translational benefit. PMID:22973222

Fellin, Tommaso; Ellenbogen, Jeffery M.; De Pitta, Maurizio; Ben-Jacob, Eshel; Halassa, Michael M.

2012-01-01

196

Modeling Skin Effect With Reduced Decoupled R-L Circuits S.Mei and Y. 1.Ismail  

E-print Network

Modeling Skin Effect With Reduced Decoupled R-L Circuits S.Mei and Y. 1.Ismail Electrical lumped-element circuit models are needed. A rule-based R-L circuit model is proposed in this paper that predicts the skin effect in the entire frequency range accurately. This circuit model only contains a few

Ismail, Yehea

197

Dynamic analysis of radial force density in brushless DC motor using 3-D equivalent magnetic circuit network method  

SciTech Connect

The distribution of radial force density in brushless permanent magnet DC motor is not uniform in axial direction. The analysis of radial force density has to consider the 3-D shape of teeth and overhand, because the radial force density causes vibration and acts on the surface of teeth inconstantly. For the analysis, a new 3-D equivalent magnetic circuit network method is used to account the rotor movement without remesh. The radial force density is calculated and analyzed by Maxwell stress tensor and discrete Fourier transform (DFT) respectively. The results of 3-D equivalent magnetic circuit method have been compared with the results of 3-D FEM.

Hur, J.; Chun, Y.D.; Lee, J.; Hyun, D.S. [Hanyang Univ., Seoul (Korea, Republic of). Dept. of Electrical Engineering

1998-09-01

198

Sheath Equivalent Electrical Circuit Model for Equilibrium Child Sheath Description  

NASA Astrophysics Data System (ADS)

The Child-Langmuir law is well known in the fields of electronics and plasma physics. This has relevance to the analytical description of the space charge sheath limited current and its dependence on the space charge sheath width. For known values of the applied wall voltage, the current and width are two unknowns to be determined self-consistently and independently. The Child-Langmuir law alone is not sufficient for self-consistent description of the equilibrium Child sheath. Here we use the concept of sheath equivalent electrical circuit model and propose an idea of current equivalence principle to develop an additional equation which closes the usual Child sheath equation. Thereafter, we carry out self-consistent and independent determination of the Child sheath current and width. It is found that the steady state (time averaged) view of Kirchoff's law fulfils the closure property of the Child sheath equation and verifies the constant current approximation of conventional Child sheath description. The proposed idea of current equivalence principle states that the hydrodynamic and electrical circuit views of the Child sheath current are equivalent, which is supposed to govern the equilibrium and dynamic behaviors of the Child sheath.

Dwivedi, C. B.; Deka, U.; Sarma, A.

199

Mathematical modeling of Fabry-Perot resonators: II. Uniformly converging multimode equivalent-circuit models.  

PubMed

Based on complex-variable analysis of a Fabry-Perot resonator as a multimode nonsymmetric two-port waveguide device, two versions of equivalent-circuit configurations are presented: Starting from a renewed study on single-mode two-pole circuits, we develop two respective multimode equivalent circuits of an almost identical configuration: one for the reflection coefficient and the other for the pass-through transmission coefficient. In the mathematics language of complex-variable analysis, the two models successfully "approximate" the two scattering coefficients through two "uniformly converging" partial-fraction series expansions. PMID:24562041

Song, G Hugh

2014-02-01

200

Spring 2014, EECE 549: Assignment 1: Introduction to Simulink and Modeling of Basic RLC Circuits  

E-print Network

Spring 2014, EECE 549: Assignment 1: Introduction to Simulink and Modeling of Basic RLC Circuits) Develop a Simulink model of the circuit shown in Fig. 1(a) using conventional Simulink block (summers Due on Monday, January 27 (in class) Fig. 1 A harmonic filter: (a) Simple model; (b) Model with more

Pulfrey, David L.

201

Time-Dependent Model of the Global Electric Circuit  

NASA Astrophysics Data System (ADS)

The Global Electric Circuit (GEC) is a circuit that is formed between the Earth's surface, which is a good conductor of electricity, and the ionosphere, a weekly-ionized plasma at around 80 km altitude [e.g., Rycroft et al., Space Sci. Rev., 137(1-4), pp. 83-105, 2008]. In the absence of any source, the GEC behaves as a leaky spherical capacitor, with the ground being the negative charged plate and the ionosphere the positive one, which discharges through the weakly conducting atmosphere creating fair-weather current, which is about 1 kA integrated over the entire Earth surface [e.g., Bering et al., Physics Today, Oct., 24-30, 1998]. It is accepted that thunderstorms are the main generators in the GEC [e.g., Williams, Atmospheric Research, 91, 140, 2009; Mareev, Physics Uspekhi, 53, 504, 2010]. In this current work, we developed a two-dimensional cylindrical time-dependent model, which calculates the quasi-electrostatic fields created by the slow accumulation of the charge in the cloud, by taking into account the Maxwellian relaxation of the charges in the conducting atmosphere. The model is capable of simulating the whole volume of the GEC and thus it has the same electrical properties as the three-dimensional spherical system. Two different kinds of boundary conditions (Dirichlet and homogeneous Neumann boundary conditions) were used in order to describe the global circulation of the current, and it has been found that both of them give the same results regarding the general contribution of a storm to the GEC. We present results regarding the response of the fair weather region to lightning transients that occur in the thunderstorm, and in the steady state limit the results of the time-dependent model are compared to static GEC solutions similar to those reported previously by Tzur and Roble [JGR, 90, 5989, 1985].

Mallios, S. A.; Pasko, V. P.

2013-12-01

202

HSPICE modelling of a solar array circuit controlled by a fet switch  

NASA Technical Reports Server (NTRS)

This paper presents a method of modeling a solar array circuit controlled by a hexfet switch on HSPICE. HSPICE models are developed for the solar array current voltage (IV) characteristic and the IRF150 hexfet. Computer simulations are made to verify rate of current change at the load. The equivalent LC circuit for the same current control is modeled to show savings in weight and power in choosing the fet switch over an LC circuit.

Cox, Deanna D.; Natarajan, T.; Day, John

1987-01-01

203

A comprehensive circuit-level model of vertical-cavity surface-emitting lasers  

Microsoft Academic Search

The increasing interest in vertical-cavity surface-emitting lasers (VCSEL's) requires the corresponding development of circuit-level VCSEL models for use in the design and simulation of optoelectronic applications. Unfortunately, existing models lack either the computational efficiency or the comprehensiveness warranted by circuit-level simulation. Thus, in this paper we present a comprehensive circuit-level model that accounts for the thermal and spatial dependence of

P. V. Mena; J. J. Morikuni; S.-M. Kang; A. V. Harton; K. W. Wyatt

1999-01-01

204

Controllable pulse parameter transcranial magnetic stimulator with enhanced circuit topology and pulse shaping  

NASA Astrophysics Data System (ADS)

Objective. This work aims at flexible and practical pulse parameter control in transcranial magnetic stimulation (TMS), which is currently very limited in commercial devices. Approach. We present a third generation controllable pulse parameter device (cTMS3) that uses a novel circuit topology with two energy-storage capacitors. It incorporates several implementation and functionality advantages over conventional TMS devices and other devices with advanced pulse shape control. cTMS3 generates lower internal voltage differences and is implemented with transistors with a lower voltage rating than prior cTMS devices. Main results. cTMS3 provides more flexible pulse shaping since the circuit topology allows four coil-voltage levels during a pulse, including approximately zero voltage. The near-zero coil voltage enables snubbing of the ringing at the end of the pulse without the need for a separate active snubber circuit. cTMS3 can generate powerful rapid pulse sequences (\\lt 10 ms inter pulse interval) by increasing the width of each subsequent pulse and utilizing the large capacitor energy storage, allowing the implementation of paradigms such as paired-pulse and quadripulse TMS with a single pulse generation circuit. cTMS3 can also generate theta (50 Hz) burst stimulation with predominantly unidirectional electric field pulses. The cTMS3 device functionality and output strength are illustrated with electrical output measurements as well as a study of the effect of pulse width and polarity on the active motor threshold in ten healthy volunteers. Significance. The cTMS3 features could extend the utility of TMS as a research, diagnostic, and therapeutic tool.

Peterchev, Angel V.; D?Ostilio, Kevin; Rothwell, John C.; Murphy, David L.

2014-10-01

205

Modelling and design for PM/EM magnetic bearings  

NASA Technical Reports Server (NTRS)

A mathematical model of a permanent magnet/electromagnet (PM/EM) radially active bearing is presented. The bearing is represented by both a reluctance model and a stiffness model. The reluctance model analyzes the magnetic circuit of the PM/EM bearings. By combining the two models, the performance of the bearing can be predicted given geometric dimensions, permanent magnet strength, and the parameters of the EM coils. The overall bearing design including the PM and EM design is subject to the performance requirement and physical constraints. A study of these requirements and constraints is discussed. The PM design is based on the required magnetic flux for proper geometric dimensions and magnet strength. The EM design is based on the stability and force slew rate consideration, and dictates the number of turns for the EM coils and the voltage and current of the power amplifier. An overall PM/EM bearing design methodology is proposed and a case study is also demonstrated.

Pang, D.; Kirk, J. A.; Anand, D. K.; Johnson, R. G.; Zmood, R. B.

1992-01-01

206

A magnetic hysteresis model  

NASA Technical Reports Server (NTRS)

The Passive Aerodynamically Stabilized Magnetically Damped Satellite (PAMS) will be deployed from the Space Shuttle and used as a target for a Shuttle-mounted laser. It will be a cylindrical satellite with several corner cube reflectors on the ends. The center of mass of the cylinder will be near one end, and aerodynamic torques will tend to align the axis of the cylinder with the spacecraft velocity vector. Magnetic hysteresis rods will be used to provide passive despin and oscillation-damping torques on the cylinder. The behavior of the hysteresis rods depends critically on the 'B/H' curves for the combination of materials and rod length-to-diameter ratio ('l-over-d'). These curves are qualitatively described in most Physics textbooks in terms of major and minor 'hysteresis loops'. Mathematical modeling of the functional relationship between B and H is very difficult. In this paper, the physics involved is not addressed, but an algorithm is developed which provides a close approximation to empirically determined data with a few simple equations suitable for use in computer simulations.

Flatley, Thomas W.; Henretty, Debra A.

1995-01-01

207

IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES, VOL. 54, NO. 5, MAY 2006 1961 A Derived Physically Expressive Circuit Model  

E-print Network

Physically Expressive Circuit Model for Multilayer RF Embedded Passives Jie Wang and Ke-Li Wu, Senior Member, IEEE Abstract--In this paper, a derived physically expressive circuit model is presented on the partial-element equivalent-circuit (PEEC) model and a simple circuit transformation. By defining

Wu, Ke-Li

208

Computer model simulation of null-flux magnetic suspension and guidance  

SciTech Connect

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.

He, Jianliang; Rote, D.M.

1992-06-01

209

Computer model simulation of null-flux magnetic suspension and guidance  

SciTech Connect

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.

He, Jianliang; Rote, D.M.

1992-01-01

210

CMOS Characterization, Modeling, and Circuit Design in the Presence of Random Local Variation.  

E-print Network

??Random local variation in CMOS transistors complicates characterization procedures, modeling efforts, simulation tools, and circuit design methodologies in highly scaled CMOS devices. Mismatch is not… (more)

Millemon, Benjamin A., Sr.

2012-01-01

211

A study on the electric and magnetic circuit of single phase line start permanent magnet motor  

Microsoft Academic Search

Recently, as the request of improvement on efficiency for the household appliances increases, a single-phase line-start permanent-magnet synchronous motor (LSPM) attracts attention. LSPM has the capacitor connected in series with the auxiliary winding and the main winding is connected in parallel with them. For this reason, the elliptic rotating magnetic field is generated by converting single-phase into quasi-two-phase. Because of

Tomoyasu Sano; Eiko Nakayama; Koichiro Sawa

2005-01-01

212

Power-Invariant Magnetic System Modeling  

E-print Network

(emf) or voltage applied across an element and the current (I) flowing through that element. It is expressed as [V], (1) where R is the electric resistance of the material [?]. Similarly, for magnetic circuits, Hopkinson’s law... (emf) or voltage applied across an element and the current (I) flowing through that element. It is expressed as [V], (1) where R is the electric resistance of the material [?]. Similarly, for magnetic circuits, Hopkinson’s law...

Gonzalez Dominguez, Guadalupe Giselle

2012-10-19

213

Magnet Falling Through Ring Model  

NSDL National Science Digital Library

The Magnet Falling Through Ring model shows the dynamics and the induced current when a magnet falls through a conducting ring. The current in the ring is computed by electromagnetic induction using to Faradayâs law and the induced emf is proportional to the negative of the rate of change of magnetic flux ?. The direction of the induced current is determined by Lenzâs law, the induced current produces magnetic field which tends to oppose the change in magnetic flux that induces such currents. The Magnet Falling Through Ring model was created using the Easy Java Simulations (Ejs) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_mosem2_em_MagnetFallingThroughRing.jar file will run the program if Java is installed.

Franciscouembre

2010-09-03

214

HF Characterization and Nonlinear Modeling of a Gapped Toroidal Magnetic Structure  

Microsoft Academic Search

The frequency dependent characteristics of a gapped toroidal structure are extracted empirically over a bandwidth that exceeds 30MHz. The analysis is complicated due to nonlinear flux distributions, magnetic properties of the core material, leakage inductance, stray capacitances, and eddy currents in the windings. A permeance model of the core is implemented to model the magnetic circuit. The model includes a

Luca Dalessandro; Willem G. Hardus Odendaal; Johann W. Kolar

2006-01-01

215

HF Characterization and Non-Linear Modeling of a Gapped Toroidal Magnetic Structure  

Microsoft Academic Search

The frequency dependent characteristics of a gapped toroidal structure are extracted empirically over a bandwidth that exceeds 30 MHz. The analysis is complicated due to non-linear flux distributions, magnetic properties of the core material, leakage inductance, stray capacitances and eddy currents in the windings. A permeance model of the core is implemented to model the magnetic circuit. The model includes

L. Dalessandro; W. G. Odendaal; J. W. Kolar

2005-01-01

216

Simplified equivalent modelling of electromagnetic emissions from printed circuit boards.  

E-print Network

??Characterization of electromagnetic emissions from printed circuit boards (PCBs) is an important issue in electromagnetic compatibility (EMC) design and analysis of modern electronic systems. This… (more)

Tong, Xin

2010-01-01

217

Chapter II MOS Transistor Modelling for MMW Circuits ChapterChapterChapterChapter IIIIIIII  

E-print Network

Chapter II MOS Transistor Modelling for MMW Circuits 15 ChapterChapterChapterChapter IIIIIIII MOS transistor model and layout issues One of the most important design issues in millimeter wave circuit design in modern MOS technologies is active devices and related parasitic elements modeling. The MOS transistor

Paris-Sud XI, Université de

218

Extraction of Gate Level Models from Transistor Circuits by FourValued Symbolic Analysis  

E-print Network

Extraction of Gate Level Models from Transistor Circuits by Four­Valued Symbolic Analysis Randal E­level representation of an MOS transistor circuit. The resulting model contains only four­valued unit and zero delay transistors, stored charge, and multiple signal strengths. It produces models with size comparable to ones

Bryant, Randal E.

219

A Simplified Model for Parameter Estimation and Circuit Analysis of Inductive-Adder Modulator  

Microsoft Academic Search

In this paper, we propose a simplified model for easy estimation of design parameters and quick analysis of fast pulsed inductive adder modulators. Analytical method is used to deduct the simplified circuit model. This model offers an easy way to understand the behavior of the inductive-adder modulator circuits and provides designers a helpful tool to estimate critical parameters such as

W. Zhang; C. Pai; J. Sandberg; Y. Tan; Y. Tian

2007-01-01

220

Application of the cavity model to lossy power-return plane structures in printed circuit boards  

Microsoft Academic Search

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

Minjia Xu; Hao Wang; Todd H. Hubing

2003-01-01

221

AN OPEN-CIRCUIT-VOLTAGE MODEL OF LITHIUM-ION BATTERIES FOR EFFECTIVE INCREMENTAL CAPACITY ANALYSIS  

E-print Network

AN OPEN-CIRCUIT-VOLTAGE MODEL OF LITHIUM-ION BATTERIES FOR EFFECTIVE INCREMENTAL CAPACITY ANALYSIS-Circuit-Voltage (OCV) is an essential part of battery models for state-of-charge (SOC) estimation. In this paper, we for battery state-of-health monitoring. In particular, the new OCV model can be used for incremental capacity

Peng, Huei

222

A Compact Model for Circuit Simulation of TFT-LCD Panel  

Microsoft Academic Search

In this paper, we report a novel compact SPICE model for circuit simulation of LCD-TVs. In this work, we generated a SPICE model for a unit cell of TFT-LCD by taking all of parasitic capacitances and resistances into account. In order to extract circuit model from a unit cell, an electrical connectivity of resistors and capacitors was generated through the

Suk-In Yoon; Sang-Ho Yoon; Chan-Yong Jung; Taeyoung Won

2006-01-01

223

Partial Element Equivalent Circuit (PEEC) models for onchip passives and interconnects  

E-print Network

Partial Element Equivalent Circuit (PEEC) models for on­chip passives and interconnects Menno E model can be formulated as an equivalent circuit. We have conducted some simple experiments to see of the electric field integral equation, which can be used to construct a full­wave electromagnetic model

Eindhoven, Technische Universiteit

224

Neurogenetic models in modeling nonlinear digital I\\/O buffer circuits  

Microsoft Academic Search

Neural network models are used as strong interpolation tools to model digital I\\/O buffer circuits accurately. Training a neural network involves use of complex training algorithms. Optimizing a neural network is complicated due to a large number of variable parameters involved in the process. Genetic algorithms are used to optimize a problem with a very large number of possible solutions

Menas Roumbakis; B. Mutnury; S. Ulrich; J. Ratcliffe; D. de Araujo; M. Cases

2005-01-01

225

Draft Submitted to J-SAC Circuit Modeling Methodology for UWB Omnidirectional Small  

E-print Network

Draft Submitted to J-SAC - 1 - Circuit Modeling Methodology for UWB Omnidirectional Small Antennas Submitted to J-SAC - 2 - Circuit Modeling Methodology for UWB Omnidirectional Small Antennas Stanley B. T to J-SAC - 3 - I. INTRODUCTION In 2002, the FCC released the use of Ultra-wideband (UWB) transmission

Southern California, University of

226

AN INFINITE DIMENSIONAL DESCRIPTOR SYSTEM MODEL FOR ELECTRICAL CIRCUITS WITH TRANSMISSION LINES  

E-print Network

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

Reis, Timo

227

Power Electronic Circuit-oriented Model for the Fuel Cell System  

Microsoft Academic Search

In this paper a fuel cell power electronics circuit-oriented simulator model development is discussed. This developed model can be employed in any power electronics simulators and thus useful for the power converter\\/controller design. From the fundamental chemical properties, the relationship that describes the electrical behavior of cell is obtained first and then parameter affect is included. Circuit synthesis procedure is

M. Veerachary; A. Shailendra Kumar

2006-01-01

228

Dynamic models and model validation for PEM fuel cells using electrical circuits  

Microsoft Academic Search

This paper presents the development of dynamic models for proton exchange membrane (PEM) fuel cells using electrical circuits. The models have been implemented in MATLAB\\/SIMULINK and Pspice environments. Both the double-layer charging effect and the thermodynamic characteristic inside the fuel cell are included in the models. The model responses obtained at steady-state and transient conditions are validated by experimental data

Caisheng Wang; M. H. Nehrir; S. Shaw

2005-01-01

229

Dynamic models and model validation for PEM fuel cells using electrical circuits  

Microsoft Academic Search

This paper presents the development of dynamic models for proton exchange membrane (PEM) fuel cells using electrical circuits. The models have been implemented in MATLAB\\/SIMULINK and PSPICE environments. Both the double-layer charging effect and the thermodynamic characteristic inside the fuel cell are included in the models. The model responses obtained at steady-state and transient conditions are validated by experimental data

Caisheng Wang; M. Hashem Nehrir; Steven R. Shaw

2005-01-01

230

Probabilistic model of fault detection in quantum circuits  

E-print Network

It is shown that the fault testing for quantum circuits does not follow conventional classical techniques. If probabilistic gate like Hadamard gate is included in a circuit then the classical notion of test vector is shown to fail. We have reported several new and distinguishing features of quantum fault and also presented a general methodology for detection of functional faults in a quantum circuit. The technique can generate test vectors for detection of different kinds of fault. Specific examples are given and time complexity of the proposed quantum fault detection algorithm is reported.

Anindita Banerjee; Anirban Pathak

2009-05-12

231

Characteristics analysis of a high speed permanent magnet synchronous generator using the transfer relations theorem and equivalent circuit method  

NASA Astrophysics Data System (ADS)

This paper presents analytical methods to predict the magnetic field distribution, electrical parameters, and output characteristics of a high speed synchronous generator equipped with surface-mounted permanent magnet. In order to analyze the magnetic field distribution and to estimate the electrical parameters, electromagnetic transfer relation (TR) theorem is employed. Moreover, output characteristics for variable resistive load and the operating speed are also obtained by solving the permanent magnet machine's equivalent circuit equation. The analytical results are validated extensively by nonlinear finite element analysis and experimental results.

Jang, Seok-Myeong; Ko, Kyoung-Jin; Park, Ji-Hoon; Cho, Han-Wook; Hong, Jung-Pyo

2008-04-01

232

Effect of surrounding air region size on finite element modeling for permanent magnetic solenoids  

NASA Astrophysics Data System (ADS)

Magnetostatic finite element modeling of permanent magnetic devices can provide accurate results only if the underlying physics is well captured in the model. A single device surrounded by an air padding region is the focus of this research. In the ideal modeling case, this padding region would be infinite in extent. Since an infinite padding region is impossible to implement, the padding sizes in modeling a permanent magnetic solenoid that can ensure accurate results were analyzed in our study. The relationship between accuracy of the simulation result and the surrounding air padding percentage in terms of the device size is demonstrated in this paper, which shows that physically impossible results can occur for a permanent magnetic solenoid if an insufficient padding percentage is used. Design engineers typically use padding percentages from 40 - 400%, and our results show that the required padding percentage depends on the openness of the magnetic circuit. A permanent magnetic solenoid may have more or less openness of the magnetic circuit when the magnetic vector of the side magnets has a larger or smaller angle ?1. For a more open magnetic circuit with ?1 near 90°, a higher padding percentage, up to 600%, is required. For a less open magnetic circuit with ?1 ? 30°, 200% padding is recommended for better accuracy.

Chen, C. H.; Lin, S.; Horwath, J. C.; Hoff, B. W.; Haworth, M. D.; Heidger, S. L.

2011-04-01

233

A current circuit model of pulsar radio emission  

E-print Network

We present the outline of a new model for the coherent radio emission of pulsars that succeeds in reproducing the energetics and brightness temperatures of the observed radio emission from the observationally deduced distances of 50-100 pulsar radii above the neutron star in a narrow region. The restrictions imposed by energy conservation, plasma dynamics of the coherent radiation process and propagation effects are used to apply the action of a plasma process like coherent inverse Compton scattering (CICS) (see Benford, 1992). In accordance with our findings (Kunzl et al. 1998a) this process requires Lorentz factors of about 10 which are lower than in most other radio emission models. This implies that no significant pair production can take place near the surface and we expect charge densities close to the Goldreich-Julian value (Goldreich & Julian (1969)). To fulfill the energetic and electrodynamic constraints the model requires constant re-acceleration in dissipation regions which can be interpreted as a voltage drop similar to that in a resistive current circuit built of a battery, connecting copper wires and a resistive load. Using the emission heights for PSR 0329+54 published by Mitra and Rankin (2002) and the spectral data from Malofeev et al. (1994) we find that a constant depth of the dissipation region of about 2 r_NS can account for the observed luminosities and spectral behavior. The extremely high peak fluxes in the substructures of single pulses can be explained by beaming effects as discussed in Kunzl et al. (1998b).

Th. Kunzl; H. Lesch; A. Jessner

2002-08-30

234

Astrocyte regulation of sleep circuits: experimental and modeling perspectives  

E-print Network

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 ...

Halassa, Michael M.

235

Basic neuron model electrical equivalent circuit: an undergraduate laboratory exercise.  

PubMed

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

Dabrowski, Katie M; Castaño, Diego J; Tartar, Jaime L

2013-01-01

236

Advanced modeling of planarization processes for integrated circuit fabrication  

E-print Network

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 ...

Fan, Wei, Ph. D. Massachusetts Institute of Technology

2012-01-01

237

Log-domain circuit models of chemical reactions  

E-print Network

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 ...

Mandal, Soumyajit

238

Basic Neuron Model Electrical Equivalent Circuit: An Undergraduate Laboratory Exercise  

PubMed Central

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

Dabrowski, Katie M.; Castano, Diego J.; Tartar, Jaime L.

2013-01-01

239

Interconnect and circuit modeling techniques for full-chip power supply noise analysis  

Microsoft Academic Search

This paper describes the interconnect and circuit modeling techniques to analyze the on-chip power supply noise for high-performance very large scale integration (VLSI) design. To reduce the complexity of full-chip analysis, a hierarchical power supply distribution model, which consists of a 12×12 package model, a 50×50 on-chip power bus model, and a distributed switching circuit model, is developed. This integrated

Howard H. Chen; J. Scott Neely

1998-01-01

240

A novel prediction method about single components of analog circuits based on complex field modeling.  

PubMed

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

Zhou, Jingyu; Tian, Shulin; Yang, Chenglin

2014-01-01

241

Phase-Boundary of several Multicube Superconducting Circuits in a Magnetic-Field of Arbitrary Magnitude and Direction  

E-print Network

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...

YI, YM; Hu, Chia-Ren.

1992-01-01

242

An engineering model of lower thalamo-cortico-basal ganglionic circuit function  

E-print Network

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 ...

Lim, Eugene J. (Eugene Jungsud), 1980-

2003-01-01

243

Compact Modeling of Nonlinear Analog Circuits Using System Identification via Semidefinite Programming and Incremental Stability Certification  

E-print Network

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 ...

Bond, Bradley N.

244

Modeling Magnetic Flux Ropes  

NASA Astrophysics Data System (ADS)

The magnetic configuration hosting prominences can be a large-scale helical magnetic flux rope. As a necessary step towards future prominence formation studies, we report on a stepwise approach to study flux rope formation. We start with summarizing our recent three-dimensional (3D) isothermal magnetohydrodynamic (MHD) simulation where a flux rope is formed, including gas pressure and gravity. This starts from a static corona with a linear force-free bipolar magnetic field, altered by lower boundary vortex flows around the main polarities and converging flows towards the polarity inversion. The latter flows induce magnetic reconnection and this forms successive new helical loops so that a complete flux rope grows and ascends. After stopping the driving flows, the system relaxes to a stable helical magnetic flux rope configuration embedded in an overlying arcade. Starting from this relaxed isothermal endstate, we next perform a thermodynamic MHD simulation with a chromospheric layer inserted at the bottom. As a result of a properly parametrized coronal heating, and due to radiative cooling and anisotropic thermal conduction, the system further relaxes to an equilibrium where the flux rope and the arcade develop a fully realistic thermal structure. This paves the way to future simulations for 3D prominence formation.

Xia, Chun; Keppens, Rony

2014-01-01

245

[Modeling and analysis of volume conduction based on field-circuit coupling].  

PubMed

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

Tang, Zhide; Liu, Hailong; Xie, Xiaohui; Chen, Xiufa; Hou, Deming

2012-08-01

246

Modeling quantum noise for efficient testing of fault-tolerant circuits  

E-print Network

Understanding fault-tolerant properties of quantum circuits is important for the design of large-scale quantum information processors. In particular, simulating properties of encoded circuits is a crucial tool for investigating the relationships between the noise model, encoding scheme, and threshold value. For general circuits and noise models, these simulations quickly become intractable in the size of the encoded circuit. We introduce methods for approximating a noise process by one which allows for efficient Monte Carlo simulation of properties of encoded circuits. The approximations are as close to the original process as possible without overestimating their ability to preserve quantum information, a key property for obtaining more honest estimates of threshold values. We numerically illustrate the method with various physically relevant noise models.

Easwar Magesan; Daniel Puzzuoli; Christopher E. Granade; David G. Cory

2012-06-23

247

SELF-HEATING IN A COUPLED THERMO-ELECTRIC CIRCUIT-DEVICE MODEL  

E-print Network

SELF-HEATING IN A COUPLED THERMO-ELECTRIC CIRCUIT-DEVICE MODEL MARKUS BRUNK AND ANSGAR J¨UNGEL Abstract. The self-heating of a coupled thermo-electric circuit-semiconductor system is mod- eled, capacitors, inductors, and voltage sources, and a thermal network. The flow of the charge carriers

Jüngel, Ansgar

248

Optimal design of generator circuit breakers up to a capacity of 2000 MVA using thermal models  

Microsoft Academic Search

Generator circuit breakers must be able to carry operating currents of several 10 kA and short time currents of several 100 kA. It is shown how a generator circuit breaker to be developed can be optimized by calculation using the thermal network method and finite element models for high operating currents. The essential parameters are found out which mainly determine

T. Schoenemann; M. Pleines; M. Schenk; H. Lobl; T. Magier

2004-01-01

249

Modeling the cosmic-ray-induced soft-error rate in integrated circuits: An overview  

Microsoft Academic Search

This paper is an overview of the concepts and methodologies used to predict soft-error rates (SER) due to cosmic and high-energy particle radiation in integrated circuit chips. The paper emphasizes the need for the SER simulation using the actual chip circuit model which includes device, process, and technology parameters as opposed to using either the discrete device simulation or generic

G. R. Srinivasan

1996-01-01

250

Fast power\\/ground network optimization based on equivalent circuit modeling  

Microsoft Academic Search

This paper presents an efficient algorithm for optimizing the area of power or ground networks in integrated circuits subject to the reliability constraints. Instead of solving the original power\\/ground networks extracted from circuit layouts as previous methods did, the new method first builds the equivalent models for many series resistors in the original networks, then the sequence of linear programming

X.-D. Sheldon Tan; C.-J. Richard Shi

2001-01-01

251

Propagation delay and short-circuit power dissipation modeling of the CMOS inverter  

Microsoft Academic Search

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

Labros Bisdounis; Spiridon Nikolaidis; O. Loufopavlou

1998-01-01

252

Equivalent-circuit model of the squeezed gas film in a silicon accelerometer  

Microsoft Academic Search

We present a new electric equivalent circuit for the forces created by a squeezed gas film between vertically moving planar surfaces. The model is realized with frequency-dependent resistors and inductors. Circuit analysis tools are applied to calculate the response of a micromechanical silicon capacitive accelerometer in both the frequency and the time domains. The simulations are shown to match the

Timo Veijola; Heikki Kuisma; Juha Lahdenperä; Tapani Ryhänen

1995-01-01

253

GABAergic circuit dysfunction in the Drosophila Fragile X syndrome model.  

PubMed

Fragile X syndrome (FXS), caused by loss of FMR1 gene function, is the most common heritable cause of intellectual disability and autism spectrum disorders. The FMR1 protein (FMRP) translational regulator mediates activity-dependent control of synapses. In addition to the metabotropic glutamate receptor (mGluR) hyperexcitation FXS theory, the GABA theory postulates that hypoinhibition is causative for disease state symptoms. Here, we use the Drosophila FXS model to assay central brain GABAergic circuitry, especially within the Mushroom Body (MB) learning center. All 3 GABAA receptor (GABAAR) subunits are reportedly downregulated in dfmr1 null brains. We demonstrate parallel downregulation of glutamic acid decarboxylase (GAD), the rate-limiting GABA synthesis enzyme, although GABAergic cell numbers appear unaffected. Mosaic analysis with a repressible cell marker (MARCM) single-cell clonal studies show that dfmr1 null GABAergic neurons innervating the MB calyx display altered architectural development, with early underdevelopment followed by later overelaboration. In addition, a new class of extra-calyx terminating GABAergic neurons is shown to include MB intrinsic ?/? Kenyon Cells (KCs), revealing a novel level of MB inhibitory regulation. Functionally, dfmr1 null GABAergic neurons exhibit elevated calcium signaling and altered kinetics in response to acute depolarization. To test the role of these GABAergic changes, we attempted to pharmacologically restore GABAergic signaling and assay effects on the compromised MB-dependent olfactory learning in dfmr1 mutants, but found no improvement. Our results show that GABAergic circuit structure and function are impaired in the FXS disease state, but that correction of hypoinhibition alone is not sufficient to rescue a behavioral learning impairment. PMID:24423648

Gatto, Cheryl L; Pereira, Daniel; Broadie, Kendal

2014-05-01

254

An in-depth noise model for giant magnetoresistance current sensors for circuit design and complementary metal-oxide-semiconductor integration  

NASA Astrophysics Data System (ADS)

Full instrumentation bridges based on spin valve of giant magnetoresistance and magnetic tunnel junction devices have been microfabricated and experimentally characterized from the DC and noise viewpoint. A more realistic model of these devices was obtained in this work, an electrical and thermal model previously developed have been improved in such a way that noise effects are also included. We have implemented the model in a circuit simulator and reproduced the experimental measurements accurately. This provides a more realistic and complete tool for circuit design where magnetoresistive elements are combined with well-known complementary metal-oxide-semiconductor modules.

Roldán, A.; Roldán, J. B.; Reig, C.; Cardoso, S.; Cardoso, F.; Ferreira, R.; Freitas, P. P.

2014-05-01

255

Changing and shielded magnetic fields suppress c-Fos expression in the navigation circuit: input from the magnetosensory system contributes to the internal representation of space in a subterranean rodent  

PubMed Central

The neural substrate subserving magnetoreception and magnetic orientation in mammals is largely unknown. Previous experiments have demonstrated that the processing of magnetic sensory information takes place in the superior colliculus. Here, the effects of magnetic field conditions on neuronal activity in the rodent navigation circuit were assessed by quantifying c-Fos expression. Ansell's mole-rats (Fukomys anselli), a mammalian model to study the mechanisms of magnetic compass orientation, were subjected to natural, periodically changing, and shielded magnetic fields while exploring an unfamiliar circular arena. In the undisturbed local geomagnetic field, the exploration of the novel environment and/or nesting behaviour induced c-Fos expression throughout the head direction system and the entorhinal–hippocampal spatial representation system. This induction was significantly suppressed by exposure to periodically changing and/or shielded magnetic fields; discrete decreases in c-Fos were seen in the dorsal tegmental nucleus, the anterodorsal and the laterodorsal thalamic nuclei, the postsubiculum, the retrosplenial and entorhinal cortices, and the hippocampus. Moreover, in inactive animals, magnetic field intensity manipulation suppressed c-Fos expression in the CA1 and CA3 fields of the hippocampus and the dorsal subiculum, but induced expression in the polymorph layer of the dentate gyrus. These findings suggest that key constituents of the rodent navigation circuit contain populations of neurons responsive to magnetic stimuli. Thus, magnetic information may be integrated with multimodal sensory and motor information into a common spatial representation of allocentric space within this circuit. PMID:20219838

Burger, Tomas; Lucova, Marcela; Moritz, Regina E.; Oelschlager, Helmut H. A.; Druga, Rastislav; Burda, Hynek; Wiltschko, Wolfgang; Wiltschko, Roswitha; Nemec, Pavel

2010-01-01

256

A Circuit-Compatible SPICE model for Enhancement Mode Carbon Nanotube Field Effect Transistors  

Microsoft Academic Search

This paper presents a circuit-compatible compact model for short channel length (5 nm~100 nm), quasi-ballistic single wall carbon nanotube field-effect transistors (CNFETs). For the first time, a universal circuit-compatible CNFET model was implemented with HSPICE. This model includes practical device non-idealities, e.g. the quantum confinement effects in both circumferential and channel length direction, the acoustical\\/optical phonon scattering in channel region

J. Deng; H.-S. P. Wong

2006-01-01

257

Three-Dimensional Electro-Thermal Verilog-A Model of Power MOSFET for Circuit Simulation  

NASA Astrophysics Data System (ADS)

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.

Chvála, A.; Donoval, D.; Marek, J.; Príbytný, P.; Molnár, M.; Mikolášek, M.

2014-04-01

258

Transcutaneous Battery Recharging By Volume Conduction and its Circuit Modeling  

Microsoft Academic Search

Many implantable devices require large capacity batteries implanted in the body. Transcutaneous battery recharging can effectively maintain the longevity of these implants. Based on this consideration we have developed a transcutaneous battery recharging circuit unit which takes advantages of skin volume conduction. This unit is able to pass 2.8 mA from the outside to the inside of pig skin with

Zhide Tang; R. J. Sclabassi; C. Sun; S. A. Hackworth; Jun Zhao; X. T. Cui; M. Sun

2006-01-01

259

Extraction of circuit models for substrate cross-talk  

Microsoft Academic Search

An increasingly urgent topic for the realization of densely packed (mixed signal) integrated circuits is prevention of cross-talk via the substrate. This paper proposes a Boundary Element Method (BEM) for calculating an admittance matrix for the substrate in order to analyze the parasitic coupling during layout verification.In contrast with standard BE methods, we propose a Green's function which is specific

T. Smedes; N. P. van der Meijs; Arjan J. van Genderen

1995-01-01

260

Modeling RF Passive Circuits using Coupled Lines and Scalable Models Sidharth Dalmia, Sung Hwan Min and Madhavan Swaminathan  

E-print Network

Modeling RF Passive Circuits using Coupled Lines and Scalable Models Sidharth Dalmia, Sung Hwan Min.swaminathan@ee.gatech.edu Abstract Coupled line sections are critical structures in distributed RF and microwave passive circuits the building blocks for other passive structures such as spiral inductors, transformers and capacitors [1

Swaminathan, Madhavan

261

Quantum game simulator, using the circuit model of quantum computation  

NASA Astrophysics Data System (ADS)

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.

Vlachos, Panagiotis; Karafyllidis, Ioannis G.

2009-10-01

262

Lunar magnetism. [primordial core model  

NASA Technical Reports Server (NTRS)

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.

Goldstein, M. L.

1975-01-01

263

Characterization and modeling of plasma etch pattern dependencies in integrated circuits  

E-print Network

A quantitative model capturing pattern dependent effects in plasma etching of integrated circuits (ICs) is presented. Plasma etching is a key process for pattern formation in IC manufacturing. Unfortunately, pattern dependent ...

Abrokwah, Kwaku O

2006-01-01

264

Characteristics and computer model simulation of magnetic damping forces in maglev systems  

SciTech Connect

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 simulations. The report also presents a simple circuit model to aid in understanding damping-force characteristics.

He, J.L.; Rote, D.M.; Chen, S.S.

1994-05-01

265

Status of the Consolidation of the LHC Superconducting Magnets and Circuits  

NASA Astrophysics Data System (ADS)

The first LHC long shutdown (LS1) started in February 2013. It was triggered by the need to consolidate the 13 kA splices between the superconducting magnets to allow the LHC to reach safely its design energy of 14 TeV center of mass. The final design of the consolidated splices is recalled. 1695 interconnections containing 10 170 splices have to be opened. In addition to the work on the 13 kA splices, the other interventions performed during the first long shut-down on all the superconducting circuits are described. All this work has been structured in a project, gathering about 280 persons. The opening of the interconnections started in April 2013 and consolidation works are planned to be completed by August 2014. This paper describes first the preparation phase with the building of the teams and the detailed planning of the operation. Then, it gives feedback from the worksite, namely lessons learnt and adaptations that were implemented, both from the technical and organizational points of view. Finally, perspectives for the completion of this consolidation campaign are given.

Tock, J. Ph; Atieh, S.; Bodart, D.; Bordry, F.; Bourcey, N.; Cruikshank, P.; Dahlerup-Petersen, K.; Dalin, J. M.; Garion, C.; Musso, A.; Ostojic, R.; Perin, A.; Pojer, M.; Savary, F.; Scheuerlein, C.

2014-05-01

266

Design Methodologies for STT-MRAM (Spin-Torque Transfer Magnetic Random Access Memory) Sensing Circuits  

NASA Astrophysics Data System (ADS)

Spin-torque transfer magnetic random access memory (STT-MRAM) is a promising technology for next generation nonvolatile universal memory because it reduces the high write current required by conventional MRAM and enables write current scaling as technology becomes smaller in size. However, the sensing margin is not improved in STT-MRAM and tends to decrease with technology scaling due to the lowered supply voltage and increased process variation. Moreover, read disturbance, which is an unwanted write in a read operation, can occur in STT-MRAM because its read and write operations use the same path. To overcome these problems, we present a load-line analysis method, which is useful for systematically analyzing the impacts of transistor size and gate voltage of MOSFETs on the sensing margin, and also propose an optimization procedure for the commonly applicable MRAM sensing circuits. This methodology constitutes an effective means to optimize the transistor size and gate voltage of MOSFETs and thus maximizes the sensing margin without causing read disturbance.

Kim, Jisu; Song, Jee-Hwan; Kang, Seung-Hyuk; Yoon, Sei-Seung; Jung, Seong-Ook

267

Dual Transformer Model based on Standard Circuit Elements for the Study of Low- and Mid-frequency Transients  

NASA Astrophysics Data System (ADS)

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.

Jazebi, Saeed

268

An Equivalent Circuit Model for Semi-parallel Plate Electrostatic Torsion Mirror  

NASA Astrophysics Data System (ADS)

An equivalent circuit model for the semi-parallel plate electrostatic torsion mirror has been developed based on the electrical circuit simulator. An analytical model for the electrostatic torque has been translated into a nonlinear dependent current source as a function of input voltages that interpret the drive voltages and the mirror angle. A use of the suspension width as a fitting parameter explained well the experimental results of frequency response and the mirror's static deflection.

Maruyama, Satoshi; Mita, Makoto; Isamoto, Keiji; Chong, Changho; Fujita, Hiroyuki; Toshiyoshi, Hiroshi

269

A coupled-circuit model for a DFIG operating under unbalanced conditions  

Microsoft Academic Search

The paper describes a time-stepped coupled-circuit model for a doubly-fed induction generator. The model, which is based on the summation of the harmonic winding inductances, is capable of representing both open- and short-circuit stator and rotor winding faults. The main purpose of this paper is to present evidence of the validity of this versatile and powerful technique and the advantages

S. Djurovic; S. Williamson

2008-01-01

270

Analysis and White-Box Modeling of Weakly Nonlinear Time-Varying Circuits  

Microsoft Academic Search

The architectural study of wireless communication systems typically requires simulations with high-level models for different analog and RF blocks. Among these blocks, frequency-translating devices such as mixers pose problems in RF circuit simulation since their response typically covers a mix of long- and short-time scales. This paper proposes a technique to analyze and model nonlinear frequency-translating RF circuits such as

Petr Dobrovolny; Gerd Vandersteen; Piet Wambacq; Stephane Donnay

2003-01-01

271

Modeling and Simulation of Short-Circuit Loss of Excitation in Powerformer  

Microsoft Academic Search

In order to analyze the performance of powerformer under loss of excitation (LOE) condition more effectively, in this paper, firstly, based on MATLAB\\/Simulink, the simulation model is constructed, the direct short-circuit LOE and the excitation winding forms short-circuit LOE with de-excitation resistance are simulated by the model; Secondly, the waveforms of excitation current, rotor speed, active power, reactive power, stator

Li Cuicui; Ge Baojun; Lv Yanling; Gu Fengling

2009-01-01

272

Thermal modeling of power gallium arsenide microwave integrated circuits  

SciTech Connect

Low-power Gallium Arsenide-based microwave circuits have been used for many years for frequencies higher than those possible with silicon technology. At the present time manufacturers are developing power devices for ever higher frequencies using GaAs MESFET's and heterojunction bipolar devices constructed with III-V compounds on GaAs substrates. There is also interest in integrating power devices on Monolithic Microwave Integrated Circuits (MMIC's). A problem with the technology is the low thermal conductivity of Gallium Arsenide and this gives rise to thermal design problems which must be solved if good reliability is to be achieved. The paper uses a three-dimensional numerical simulator to study this problem and in particular examines the approximations which are possible in performing realistic assessments of the thermal resistance of typical GaAs power device structures under steady-state conditions.

Webb, P.W. (Univ. of Birmingham, Edgbaston (United Kingdom))

1993-05-01

273

2.5. SUMMARY OF THE MODEL 49 Figure 2.25: Simulation of the stack circuit.  

E-print Network

2.5. SUMMARY OF THE MODEL 49 Figure 2.25: Simulation of the stack circuit. The dotted square developed a model circuit that adheres to the important neurobio­ logical constraints of fan­in, fan indicates the window of attention. The circuit is shown attending to the `A' at the lowest resolution level

Olshausen, Bruno

274

Small-signal circuit modeling in the frequency-domain by computer-aided time-domain simulation  

Microsoft Academic Search

The possibility of obtaining the frequency-domain dynamic model of a circuit from transient analysis data provided by a circuit simulator is shown. The computer-aided design (CAD) program FREDOMSIM, which governs the simulations, processes the output data, and supplies the results in a well suited manner for design optimization, is introduced. Feedback circuits are modeled with all their feedback loops open,

Piero Maranesi

1992-01-01

275

Generalized equivalent circuit model for ultra wideband antenna structure with double steps for energy scavenging  

NASA Astrophysics Data System (ADS)

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.

>Oon Kheng Heong, Goh Chin; Chakrabarty, Chandan Kumar; >Goh Tian Hock,

2013-06-01

276

Modeling and fabrication of tuned circuits for optical meta-materials  

NASA Astrophysics Data System (ADS)

Recently there has been a drive to create artificial optical materials, or meta-materials, with a specified electrical permittivity and magnetic permeability at optical frequencies. Control over these properties can give rise to new physical phenomena, such as a negative refractive index and "super lensing", with potential applications in nanophotonic systems and nanolithography. Because most materials do not exhibit magnetic behaviour at optical frequencies, control over the effective magnetic permeability is achieved using patterned metal structures much smaller than the wavelength of light. The electric currents induced in the structures produce magnetic fields that may be in phase or may oppose the magnetic field of the incident light. When combined with dielectric materials, these structuresform coupled inductor-capacitor (LC) circuits that can resonate at frequencies in the optical spectrum. Since the resonant properties of the LC circuits control the properties of the meta-material, it is important to understand how changes in shape, size and the position of the subwavelength components affect the resonances. Using the Finite Difference Time Domain (FDTD) method, we study a number of different inductor-capacitor configurations. By applying the concepts of lumped impedance to the electromagnetic fields, the resonant frequencies and Q factors of the tuned optical circuits are determined from the FDTD data. Our in-house electron beam lithography system has been used to fabricate some of the structures. Results of the simulations, the nano-fabrication process and experiments on the meta-materials will be presented.

Davis, T. J.

2006-01-01

277

Superior model for fault tolerance computation in designing nano-sized circuit systems  

NASA Astrophysics Data System (ADS)

As CMOS technology scales nano-metrically, reliability turns out to be a decisive subject in the design methodology of nano-sized circuit systems. As a result, several computational approaches have been developed to compute and evaluate reliability of desired nano-electronic circuits. The process of computing reliability becomes very troublesome and time consuming as the computational complexity build ups with the desired circuit size. Therefore, being able to measure reliability instantly and superiorly is fast becoming necessary in designing modern logic integrated circuits. For this purpose, the paper firstly looks into the development of an automated reliability evaluation tool based on the generalization of Probabilistic Gate Model (PGM) and Boolean Difference-based Error Calculator (BDEC) models. The Matlab-based tool allows users to significantly speed-up the task of reliability analysis for very large number of nano-electronic circuits. Secondly, by using the developed automated tool, the paper explores into a comparative study involving reliability computation and evaluation by PGM and, BDEC models for different implementations of same functionality circuits. Based on the reliability analysis, BDEC gives exact and transparent reliability measures, but as the complexity of the same functionality circuits with respect to gate error increases, reliability measure by BDEC tends to be lower than the reliability measure by PGM. The lesser reliability measure by BDEC is well explained in this paper using distribution of different signal input patterns overtime for same functionality circuits. Simulation results conclude that the reliability measure by BDEC depends not only on faulty gates but it also depends on circuit topology, probability of input signals being one or zero and also probability of error on signal lines.

Singh, N. S. S.; Asirvadam, V. S.; Muthuvalu, M. S.

2014-10-01

278

866 IEEE TRANSACTIONS ON MAGNETICS, VOL. 44, NO. 6, JUNE 2008 Dynamical Models for Eddy Current in Ferromagnetic Cores Introduced in  

E-print Network

is provided. Index Terms--AC circuit breakers (CBs), eddy currents, magnetic hysteresis, optimization methods. Such a device is composed of three parts: the differential current sensor [1], the electronic circuit866 IEEE TRANSACTIONS ON MAGNETICS, VOL. 44, NO. 6, JUNE 2008 Dynamical Models for Eddy Current

Boyer, Edmond

279

Circuit-quantum electrodynamics with direct magnetic coupling to single-atom spin qubits in isotopically enriched 28Si  

NASA Astrophysics Data System (ADS)

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 28Si 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.

Tosi, Guilherme; Mohiyaddin, Fahd A.; Huebl, Hans; Morello, Andrea

2014-08-01

280

A Detailed Circuit Model for Semiconductor Optical Amplifier Incorporating Thermal Effects  

NASA Astrophysics Data System (ADS)

A detailed circuit model for semiconductor optical amplifier, which incorporates thermal and spectral behavior, is reported. The rate equations of semiconductor optical amplifier form the basis for the equivalent circuit development. The circuit is simulated for static and dynamic conditions and its performance as amplifier, modulator and detector are evaluated. Further, thermal effects on the characteristics of SOA are determined. The SOA performance is studied in the temperature range of 283-343 K and the results are found to agree well with the literature.

Rekha, E.; Madhan, M. Ganesh

2014-09-01

281

A functional validation methodology based on error models for measuring the quality of digital integrated circuits  

NASA Astrophysics Data System (ADS)

Functional validation plays an important role in the design cycle of digital integrated circuits. The generation of good test benches is required for checking the complete circuit behaviour. Early location of design errors could highly reduce the development time and cost for these circuits. There are several initiatives for the development of methods that enhance the functional validation of a design. Traditionally, logic abstraction level has been most employed for this purpose, but recent years have shown a strong trend to treat the problem at higher abstraction levels, where design teams normally work. High abstraction levels and automatic synthesis tools are currently being used in top-down methodology. These aspects make difficult to find out design errors when the circuit is described in lower levels of abstraction. It is crucial to obtain a complete functional validation system applicable in the first design stages, where circuits are currently being designed, and also usable along the whole design process for further test plans. In this paper we propose a complete methodology for performing high quality functional validation. The proposed method checks the capability of a given test bench to detect design errors in a circuit description. This checking employs functional simulation of the circuit description at RT level together with the application of error models. An automatic and formal protocol has been developed so that design teams could apply it with no extra effort. The method provides a measurement of the quality of functional validation as well as the location of non-enough validated areas in the circuit. Therefore, the proposed method helps designers in the process of performing the functional validation of their circuits, which could be applied automatically from RT descriptions to lower abstraction levels. Finally, experimental results have proved the correctness of the proposed method as well as the error models applied.

Lopez-Ongil, Celia; Entrena-Arrontes, Luis; Riesgo-Alcaide, Teresa; Uceda-Antolin, Javier

2005-06-01

282

Quasi-linear vacancy dynamics modeling and circuit analysis of the bipolar memristor.  

PubMed

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

Abraham, Isaac

2014-01-01

283

Quasi-Linear Vacancy Dynamics Modeling and Circuit Analysis of the Bipolar Memristor  

PubMed Central

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

Abraham, Isaac

2014-01-01

284

Common circuit defect of excitatory-inhibitory balance in mouse models of autism  

Microsoft Academic Search

One unifying explanation for the complexity of Autism Spectrum Disorders (ASD) may lie in the disruption of excitatory\\/inhibitory\\u000a (E\\/I) circuit balance during critical periods of development. We examined whether Parvalbumin (PV)-positive inhibitory neurons,\\u000a which normally drive experience-dependent circuit refinement (Hensch Nat Rev Neurosci 6:877–888, 1), are disrupted across heterogeneous ASD mouse models. We performed a meta-analysis of PV expression in

Nadine Gogolla; Jocelyn J. LeBlanc; Kathleen B. Quast; Thomas C. Südhof; Michela Fagiolini; Takao K. Hensch

2009-01-01

285

Improved equivalent circuit and analytical model for amorphous silicon solar cells and modules  

Microsoft Academic Search

An improved equivalent circuit for hydrogenated amorphous silicon (a-Si:H) solar cells and modules is presented. It is based on the classic combination of a diode with an exponential current-voltage characteristic, of a photocurrent source plus a new term representing additional recombination losses in the i-layer of the device. This model\\/equivalent circuit matches the I(V) curves of a-Si:H cells over an

J. Merten; J. M. Asensi; C. Voz; A. V. Shah; R. Platz; J. Andreu

1998-01-01

286

Transient modeling and performance of variable-speed permanent-magnet motors  

Microsoft Academic Search

The d-q equivalent circuit models for surface-mounted permanent magnet motors are presented and are validated through tests on a motor with neodymium-iron-boron magnets built in a 5 hp induction motor frame. The magnetic conductivity is shown to have a negligible effect on dynamic response. The response is limited mainly by the link voltage of the inverter. An expression is developed

T. Sebastian; G. R. Slemon

1989-01-01

287

Reduced-Order Dynamic Modeling of Multiple-Winding Power Electronic Magnetic Components  

Microsoft Academic Search

Dynamic high-fidelity magnetic equivalent circuits (HFMEC) are viable tool for accurate, physics-based modeling of magnetic components. However, such model formulation typically requires hundreds or thousands of state variables to accurately represent the eddy current dynamics. A reduced-order HFMEC modeling approach has been recently introduced for single-winding systems, e.g., inductors. This letter extends the HFMEC approach to multiple-winding power-electronic transformers. First,

Ali Davoudi; Patrick L. Chapman; Juri Jatskevich; Hamid Behjati

2012-01-01

288

Phenomenological models of magnetization damping  

NASA Astrophysics Data System (ADS)

In the last 70 years many models have been published for the relaxation of magnetization precession in ferromagnetic materials. Such models are important to predict energy loss for three phenomena: the free precession decay, the precession driven by an applied microwave field, and the noise of a system in equilibrium. Five models of magnetization damping are typical and were selected for this thesis: Landau-Lifshitz (LL) damping, Bloch-Bloembergen (BB) damping, Codrington-Olds-Torrey (COT) damping, Gilbert (G) damping and Modified Bloch-Bloembergen (MBB) damping. Traditionally, these models have been characterized in the small-signal limit by their susceptibility tensors, which relate the complex amplitudes of driving field and the magnetization response in a linear manner. This work categorizes the five damping models according to which field or magnetization components drive the damping. The models are compared with regard to their relaxation rate of the free decay, the geometrical shape of their trajectory, their susceptibility tensor, their energy loss for the precession driven by an external microwave field, and their thermal noise in equilibrium. The energy loss of the driven precession is determined both as time-averaged loss and as instantaneous loss. The analyses in this work take advantage of the Smith matrix form of the equations of motion for the magnetization precession in the small-signal limit. The Smith matrix form is the general form of a linearized system of coupled harmonic oscillators, solved for the external driving force. Traditionally, energy loss and noise power spectra have been calculated with the components of the susceptibility tensor involving bulky ratios of complex expressions. In this work, all calculations are carried out with the real-valued matrices that multiply the magnetization and its derivative in the Smith form of the equations of motion. The three main advantages are the following: (a) The calculations are simpler. (b) Many results about energy loss and thermal noise are expressed in simple form in terms of a single matrix, the symmetric part of the damping matrix, (c) The Smith matrix form allows calculation of instantaneous, time-dependent loss, where traditionally only time-averaged loss was considered. The power spectra of field noise as well as magnetization noise are analyzed with the fluctuation-dissipation theorem and the Wiener-Khinchine theorem. In this work a classical proof of the fluctuation-dissipation theorem is given, which is more elementary than most found in the literature and uses Boltzmann statistics and ordinary differential equations.

Kraemer, Michael Andreas

289

A Circuit Level Fault Model for Resistive Shorts of MOS Gate Oxide , Wangqi Qiu  

E-print Network

short model is to transform the effect of the resistive short into a delay fault or a logic faultA Circuit Level Fault Model for Resistive Shorts of MOS Gate Oxide Xiang Lu , Zhuo Li , Wangqi Qiu faults. In this paper, we propose a simple and realistic delay fault model for gate oxide shorts

Walker, Duncan M. "Hank"

290

Using Queueing Network Models to Set Lot-sizing Policies for Printed Circuit Board Assembly Operations  

E-print Network

1 Using Queueing Network Models to Set Lot-sizing Policies for Printed Circuit Board Assembly because more setup time is incurred. In this paper, we propose the use of queueing network models to determine the best lot-sizing policy that minimizes the WIP. The queueing network model is validated

Dessouky, Maged

291

Equivalent circuit model of an ultra-thin polarization-independent triple band metamaterial absorber  

NASA Astrophysics Data System (ADS)

This paper presents equivalent circuit modeling of an ultra-thin polarization-independent metamaterial microwave absorber consisting of three concentric closed ring resonators (CRR). The unit cell size as well as the other geometrical dimensions like radii and widths of the rings are optimized so that absorptions take place at three distinct frequencies near to the middle of the FCC defined radar spectrum eg., at 5.50 GHz, 9.52 GHz and 13.80 GHz with peak absorptivities of 94.1%, 99.6% and 99.4% respectively. The equivalent circuit model of the triple band absorber has been developed sequentially considering the single band and double band absorber models. The circuit simulation of the final model agrees well with the full-wave simulation, thus validating the modeling technique. The structure is also fabricated and experimental absorption peaks are found close to the simulated values.

Bhattacharyya, Somak; Ghosh, Saptarshi; Srivastava, Kumar Vaibhav

2014-09-01

292

Optimization of high-speed CMOS logic circuits with analytical models for signal delay, chip area, and dynamic power dissipation  

Microsoft Academic Search

Signal delay, chip area, and power dissipation are conflicting criteria for designing high-performance VLSI MOS circuits. Global optimization of transistor sizes in digital CMOS logic circuits with the design tool multiobjective gate-level optimization (MOGLO) is described. Analytical models for the design objectives are presented, and algorithms are discussed. Different techniques were combined to solve the circuit optimization problem with low

Bernhard Hoppe; Gerd Neuendorf; Doris Schmitt-landsiedel; J. Will Specks

1990-01-01

293

Space-mapping optimization of microwave circuits exploiting surrogate models  

Microsoft Academic Search

A powerful new space-mapping (SM) optimization algorithm is presented in this paper. It draws upon recent developments in both surrogate model-based optimization and modeling of microwave devices, SM optimization is formulated as a general optimization problem of a surrogate model. This model is a convex combination of a mapped coarse model and a linearized fine model. It exploits, in a

Mohamed H. Bakr; John W. Bandler; Kaj Madsen; José Ernesto Rayas-Sánchez; J. Sondergaard

2000-01-01

294

Current Sensor Modeling With A FE-Tuned MEC: Parameters Identification Protocol  

Microsoft Academic Search

This paper presents a magnetic circuit modeling of closed loop Hall-effect current sensors based on a magnetic equivalent circuit which could be simulated with a circuit type simulation software (PSPICE model). First, the principle of measurement of the closed loop Hall-effect current sensors is described, then, the magnetic equivalent circuit (MEC) modeling justified by the engineers' model needs is elaborated.

F. Sixdenier; M. A. Raulet

2012-01-01

295

Examination of Ventricular Contraction Function Using Electrical Lumped Circuit Model of Circulation System  

NASA Astrophysics Data System (ADS)

Presently, many of the already proposed blood circulation models are mainly partial models although they are precise models. A complete model that is a combination of these partial models are difficult to analyze because it is complicated to consider both the viscosity of blood and circulatory details at the same time. So, it is difficult to control the model parameters in order to adapt to various cases of circulatory diseases. This paper proposes a complete circulation model as a lumped electrical circuit, which is comparatively simple. In the circuit model, total blood is modeled as seven lumped capacitors, representing the functions of atriums, ventricles, arteries, veins and lungs. We regard the variation of the ventricle capacitance as the driving force of the complete circulation model. In our model, we considered only the variation of pressure between each part and the blood capacity of each part. In particular, the contraction function of the left ventricle is examined under the consideration of whole blood circulation.

Ito, Mitsuyo; Koya, Yoshiharu; Mizoshiri, Isao

296

A Wide-Band Lumped Circuit Model of Eddy Current Losses in a Coil with a Coaxial Insulation System and a Stranded Conductor  

Microsoft Academic Search

This paper presents a wide-band lumped circuit model of eddy current losses in a coaxially insulated coil. The wide frequency range of the model is achieved by means of dual and extended Cauer circuits, equivalent circuits used for eddy current modeling. The complete lumped circuit reproduces the expected response well. However, because of resonances in the coil, the model cannot

Par Holmberg; Mats Leijon; Torbjorn Wass

2002-01-01

297

A digital neurmorphic circuit for a simplified model of astrocyte dynamics.  

PubMed

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

Nazari, Soheila; Faez, Karim; Karami, Ehsan; Amiri, Mahmood

2014-10-17

298

Development of magnetic force modeling equipment for magnetic levitation system  

Microsoft Academic Search

In this paper, we propose a modeling equipment that obtains every equilibrium point of a magnetic levitation system automatically. To obtain every equilibrium point, we develop an automatic modeling equipment that measures the magnetic force exerted on the levitation object, the coil current of electromagnet, and the distance between the levitation object and the electromagnet. The modeling equipment is composed

Ji-Hyuk Yang; Young-Sam Lee; Oh-Kyu Kwon

2010-01-01

299

Modeling Magnetic Properties in EZTB  

NASA Technical Reports Server (NTRS)

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.

Lee, Seungwon; vonAllmen, Paul

2007-01-01

300

LARGE SCALE DISTRIBUTED PARAMETER MODEL OF MAIN MAGNET SYSTEM AND FREQUENCY DECOMPOSITION ANALYSIS  

SciTech Connect

Large accelerator main magnet system consists of hundreds, even thousands, of dipole magnets. They are linked together under selected configurations to provide highly uniform dipole fields when powered. Distributed capacitance, insulation resistance, coil resistance, magnet inductance, and coupling inductance of upper and lower pancakes make each magnet a complex network. When all dipole magnets are chained together in a circle, they become a coupled pair of very high order complex ladder networks. In this study, a network of more than thousand inductive, capacitive or resistive elements are used to model an actual system. The circuit is a large-scale network. Its equivalent polynomial form has several hundred degrees. Analysis of this high order circuit and simulation of the response of any or all components is often computationally infeasible. We present methods to use frequency decomposition approach to effectively simulate and analyze magnet configuration and power supply topologies.

ZHANG,W.; MARNERIS, I.; SANDBERG, J.

2007-06-25

301

Validation of an Accurate Three-Dimensional Helical Slow-Wave Circuit Model  

NASA Technical Reports Server (NTRS)

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.

Kory, Carol L.

1997-01-01

302

A new circuit model of HgCdTe photodiode for SPICE simulation of integrated IRFPA  

NASA Astrophysics Data System (ADS)

We propose a novel sub circuit model to simulate HgCdTe infrared photodiodes in a circuit simulator, like PSPICE. We have used two diodes of opposite polarity in parallel to represent the forward biased and the reverse biased behavior of an HgCdTe photodiode separately. We also connected a resistor in parallel with them to represent the ohmic shunt and a constant current source to represent photocurrent. We show that by adjusting the parameters in standard diode models and the resistor and current values, we could actually fit the measured data of our various HgCdTe photodiodes having different characteristics. This is a very efficient model that can be used for simulation of readout integrated circuit (ROIC) for HgCdTe IR photodiode arrays. This model also allows circuit level Monte Carlo simulation on a complete IRFPA at a single circuit simulator platform to estimate the non-uniformity for given processes of HgCdTe device fabrication and Si ROIC fabrication.

Saxena, Raghvendra Sahai; Saini, Navneet Kaur; Bhan, R. K.; Sharma, R. K.

2014-11-01

303

Reinforcement-Based Decision Making in Corticostriatal Circuits: Mutual Constraints by Neurocomputational and Diffusion Models  

Microsoft Academic Search

In this letter, we examine the computational mechanisms of reinforce-ment-based decision making. We bridge the gap across multiple levels of analysis, from neural models of corticostriatal circuits—the basal ganglia (BG) model (Frank, 2005, 2006) to simpler but mathematically tractable diffusion models of two-choice decision making. Specifically, we generated simulated data from the BG model and fit the diffusion model (Ratcliff,

Roger Ratcliff; Michael J. Frank

2012-01-01

304

Study of the DC Performance of Fabricated Magnetic Tunnel Junction Integrated on Back-End Metal Line of CMOS Circuits  

NASA Astrophysics Data System (ADS)

In this paper, we have succeeded in the fabrication of high performance Magnetic Tunnel Junction (MTJ) which is integrated in CMOS circuit with 4-Metal/1-poly Gate 0.14µm CMOS process. We have measured the DC characteristics of the MTJ that is fabricated on via metal of 3rd layer metal line. This MTJ of 60×180nm2 achieves a large change in resistance of 3.52k? (anti-parallel) with TMR ratio of 151% at room temperature, which is large enough for sensing scheme of standard CMOS logic. Furthermore, the write current is 320µA that can be driven by a standard MOS transistor. As the results, it is shown that the DC performance of our fabricated MTJ integrated in CMOS circuits is very good for our novel spin logic (MTJ-based logic) device.

Iga, Fumitaka; Kamiyanagi, Masashi; Ikeda, Shoji; Miura, Katsuya; Hayakawa, Jun; Hasegawa, Haruhiro; Hanyu, Takahiro; Ohno, Hideo; Endoh, Tetsuo

305

Strongly magnetized classical plasma models  

NASA Technical Reports Server (NTRS)

Discrete particle processes in the presence of a strong external magnetic field were investigated. These processes include equations of state and other equilibrium thermodynamic relations, thermal relaxation phenomena, transport properties, and microscopic statistical fluctuations in such quantities as the electric field and the charge density. Results from the equilibrium statistical mechanics of two-dimensional plasmas are discussed, along with nonequilibrium statistical mechanics of the electrostatic guiding-center plasma (a two-dimensional plasma model).

Montgomery, D.; Peyraud, J.; Dewitt, C.

1974-01-01

306

A Visualization Tool for CFD Models of Convectively Cooled Printed Circuit Boards  

E-print Network

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

Recktenwald, Gerald

307

Modelling multiple traffic streams subject to trunk reservation in circuit-switched networks  

Microsoft Academic Search

Trunk reservation is often used as protection against overload traffic in circuit-switched networks employing adaptive routing. This paper presents a two-moment method for modelling multiple traffic streams that are subject to trunk reservation. The approach used in this study has been to model the various traffic streams offered to a link in terms of their aggregate, determine the blocking experienced

M. Rajaratnam; F. Takawira

1996-01-01

308

2006 29 1 A physics-based equivalent circuit model for LTCC Helical  

E-print Network

2006 29 1 601 Abstract A physics-based equivalent circuit model for LTCC Helical type Inductors is presented. All of the electromagnetic couplings between conductors are included in the model and the number of Low Temperature Co-fired Ceramic Helical Inductors Keun Heo, Juhwan Lim, Sungwoo Hwang Dept

Hwang, Sung Woo

309

Analysis of Simulation-Driven Numerical Performance Modeling Techniques for Application to Analog Circuit  

E-print Network

Analysis of Simulation-Driven Numerical Performance Modeling Techniques for Application to Analog circuit optimization if one uses numerical performance modeling on simulation data to relate design.U. Leuven Leuven, Belgium Abstract--There is promise of efficiency gains in simulator-in- the-loop analog

Fernandez, Thomas

310

MODELS FOR AN ANESTHESIA BREATHING CIRCUIT Paul E. Bigeleisen + and Margaret Cheney ++  

E-print Network

MODELS FOR AN ANESTHESIA BREATHING CIRCUIT Paul E. Bigeleisen + and Margaret Cheney ++ + Department of Anesthesia, St. Paul Ramsey Medical Center, St. Paul, MN 55101; per­ manent address: Department­4824. ABSTRACT This paper presents a mathematical model of a semi­closed anesthesia breathing cir­ cuit

Cheney, Margaret

311

A General Approach to Sampled-Data Modeling for Power Electronic Circuits  

Microsoft Academic Search

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

George C. Verghese; Malik E. Elbuluk; John G. Kassakian

1986-01-01

312

Use of Lorente de No's neuron circuit model for describing acceleratory nystagmus. [bioelectric labyrinth oculomotor responses  

NASA Technical Reports Server (NTRS)

Results of a previous metric analysis and an electronic simulation of acceleratory nystagmus are given. On this basis, a tentative mathematical model for describing acceleratory nystagmus is reported. The essential content of the model is Lorente de No's neuron circuit, to which the two-factor theory of excitation has been applied.

Valentinuzzi, M.

1973-01-01

313

NEURAL MODELS FOR SOCIAL DEVELOPMENT IN SHARED PARIETO-MOTOR CIRCUITS  

E-print Network

.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

Pitti, Alexandre

314

Parameter extraction for HBT's temperature dependent large signal equivalent circuit model [MMIC oscillator  

Microsoft Academic Search

An eleven node large signal heterojunction bipolar transistors (HBT) model in hybrid-? configuration is investigated which is derived from HBT topology. This is the first circuit simulation model where the temperature is introduced as a variable simulation parameter using the concept of thermal resistance and pseudotemperature to account for the temperature dependent thermal conductivity of GaAs. The temperature and bias

P. Baureis; Ditter Seitzer

1993-01-01

315

A PSpice circuit model for low-pressure gaseous discharge lamps operating at high frequency  

Microsoft Academic Search

A simple, but accurate, PSpice circuit model simulating the electrical characteristics of low-pressure gaseous discharge lamp operating at high frequency is proposed. The model is constructed from a two-parameter equation and is suitable for computer simulation and analytic derivation in a preliminary design of electronic dimming ballasts. Simulated and measured results are used to verify the theoretical discussion

Tsai-Fu Wu; Jin-Chyuan Hung; Te-Hung Yu

1997-01-01

316

Controlled-source analogous circuits and SPICE models for piezoelectric transducers  

Microsoft Academic Search

Transmission line analogous circuits for piezoelectric transducers are developed which employ controlled sources rather than the traditional transformer to model the coupling between the electrical and the mechanical systems. A novel method is used to derive each model that consists of adding a term that is equal to zero to one of the device electromechanical equations. When this is done,

W. Marshall Leach

1994-01-01

317

Modeling and control of a LN2-GN2 operated closed circuit cryogenic wind tunnel  

NASA Technical Reports Server (NTRS)

An explicit but simple lumped parameter nonlinear multivariable model of a LN2-GN2-operated closed circuit cryogenic wind tunnel has been developed and its basic features have been experimentally validated. The model describes the mass-energy interaction involved in the cryogenic tunnel process and includes the real gas properties of nitrogen gas.

Balakrishna, S.; Thibodeaux, J. J.

1979-01-01

318

Lumped-circuit models for nonlinear inductors exhibiting hysteresis loops  

Microsoft Academic Search

A new mathematical model of dynamic hysteresis loops is presented. The model is completely specified by two strictly monotonically increasing functions: a restoring function f(.) and a dissipation function g(.). Simple procedures are given for constructing these two functions so that the resulting model will simulate a given hysteresis loop exactly. The model is shown to exhibit many important hysteretic

L. Chua; K. Stromsmoe

1970-01-01

319

Analyzing the effects of post couplers in DTL tuning by the equivalent circuit model  

E-print Network

Stabilization of the accelerating field in Drift Tube Linac(DTL) is obtained by inserting Post Couplers(PCs).On the basis of the circuit model equivalent for the DTL with and without asymmetrical PCs, stabilization is deduced quantitatively: let $\\delta \\omega/\\omega_0$ be the relative frequency error, then we discover that the sensitivity of field to perturbation is proportional to $\\sqrt{\\delta \\omega / \\omega_0}$ without PCs and to $\\delta \\omega/\\omega_0$ with PCs. Then we adapt the circuit model of symmetrical PCs for the case of asymmetrical PCs. The circuit model shows how the slope of field distribution is changed by rotating the asymmetrical PCs and illustrates that the asymmetrical PCs have the same effect as the symmetrical ones in stabilization.

Jia, Xiaoyu

2013-01-01

320

Caveats in modeling a common motif in genetic circuits  

NASA Astrophysics Data System (ADS)

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.

Labavi?, Darka; Nagel, Hannes; Janke, Wolfhard; Meyer-Ortmanns, Hildegard

2013-06-01

321

Low-intensity repetitive transcranial magnetic stimulation improves abnormal visual cortical circuit topography and upregulates BDNF in mice.  

PubMed

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

Makowiecki, Kalina; Harvey, Alan R; Sherrard, Rachel M; Rodger, Jennifer

2014-08-01

322

Equivalent circuit of radio frequency-plasma with the transformer model.  

PubMed

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

Nishida, K; Mochizuki, S; Ohta, M; Yasumoto, M; Lettry, J; Mattei, S; Hatayama, A

2014-02-01

323

A framework for scalable parameter estimation of gene circuit models using structural information  

PubMed Central

Motivation: Systematic and scalable parameter estimation is a key to construct complex gene regulatory models and to ultimately facilitate an integrative systems biology approach to quantitatively understand the molecular mechanisms underpinning gene regulation. Results: Here, we report a novel framework for efficient and scalable parameter estimation that focuses specifically on modeling of gene circuits. Exploiting the structure commonly found in gene circuit models, this framework decomposes a system of coupled rate equations into individual ones and efficiently integrates them separately to reconstruct the mean time evolution of the gene products. The accuracy of the parameter estimates is refined by iteratively increasing the accuracy of numerical integration using the model structure. As a case study, we applied our framework to four gene circuit models with complex dynamics based on three synthetic datasets and one time series microarray data set. We compared our framework to three state-of-the-art parameter estimation methods and found that our approach consistently generated higher quality parameter solutions efficiently. Although many general-purpose parameter estimation methods have been applied for modeling of gene circuits, our results suggest that the use of more tailored approaches to use domain-specific information may be a key to reverse engineering of complex biological systems. Availability: http://sfb.kaust.edu.sa/Pages/Software.aspx Contact: xin.gao@kaust.edu.sa Supplementary information: Supplementary data are available at Bioinformatics online. PMID:23813015

Kuwahara, Hiroyuki; Fan, Ming; Wang, Suojin; Gao, Xin

2013-01-01

324

Modified hyperspheres algorithm to trace homotopy curves of nonlinear circuits composed by piecewise linear modelled devices.  

PubMed

We present a homotopy continuation method (HCM) for finding multiple operating points of nonlinear circuits composed of devices modelled by using piecewise linear (PWL) representations. We propose an adaptation of the modified spheres path tracking algorithm to trace the homotopy trajectories of PWL circuits. In order to assess the benefits of this proposal, four nonlinear circuits composed of piecewise linear modelled devices are analysed to determine their multiple operating points. The results show that HCM can find multiple solutions within a single homotopy trajectory. Furthermore, we take advantage of the fact that homotopy trajectories are PWL curves meant to replace the multidimensional interpolation and fine tuning stages of the path tracking algorithm with a simple and highly accurate procedure based on the parametric straight line equation. PMID:25184157

Vazquez-Leal, H; Jimenez-Fernandez, V M; Benhammouda, B; Filobello-Nino, U; Sarmiento-Reyes, A; Ramirez-Pinero, A; Marin-Hernandez, A; Huerta-Chua, J

2014-01-01

325

Towards a comprehensive Global Electric Circuit model: Conductivity and its variability in WACCM model simulations  

NASA Astrophysics Data System (ADS)

As an important step for increasing our understanding of the global electric circuit, the AC-GCM (atmospheric chemistry general circulation model) WACCM has been extended to provide a calculation of atmospheric conductivity. This is the first time an AC-GCM is used for this purpose. Such model simulations are ideally suited for conductivity calculations and are a significant improvement to previous studies. The advancements are based on the given model data consistency as well as the possibility for controlled experiments to study factors of variability in conductvity. Most importantly, the model considers ionization from galactic cosmic rays, solar proton events and radon, and loss processes from aerosols and clouds. The aerosol representation through CARMA (a sectional aerosol microphysical model available within WACCM) provides a realistic computation of aerosol effects for the first time. A flexible module implementation allows for the use of different parameterizations and external datasets. The module can be used online or offline (1-D or 3-D) using existing model output. We present and evaluate the modelled global maps of conductivity and its variability due to the sources and sinks of ionization. This first of a kind modeling shows that aerosols can have a strong impact on conductivity especially at low latitudes.

Baumgaertner, Andreas J. G.; Neely, Ryan, III; Lucas, Greg; Thayer, Jeffrey

2013-04-01

326

Compact modeling of nonlinear distortion in analog communication circuits  

Microsoft Academic Search

The design of analog front-ends of digital telecommunicationtransceivers requires simulations at the architecturallevel. The nonlinear nature of the analog front-end blocksis a complication for their modeling at the architecturallevel, especially when the nonlinear behavior is frequencydependent. This paper describes a method to derive a bottom-up model of nonlinear analog continuous-time circuitsused in communication systems. The models take into accountfrequency dependence

Piet Wambacq; Petr Dobrovolný; Stéphane Donnay; Marc Engles; Ivo Bolsens

2000-01-01

327

Verilog-A modeling of SPAD for circuit simulations  

NASA Astrophysics Data System (ADS)

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.

Yang, Hong-jiao; Jin, Xiang-liang; Zhou, Xiao-ya; Chen, Chang-ping; Luo, Jun

2013-08-01

328

Automatic generation of accurate circuit models of 3-D interconnect  

Microsoft Academic Search

In order to optimize high-speed systems, designers need tools that automatically generate reduced order SPICE compatible models from geometric descriptions of interconnect and packaging. In this paper, we consider structures small compared to a wavelength, and use a discretized integral formulation combined with an Arnoldi-based model-order reduction strategy to compute efficiently accurate reduced-order models from three-dimensional (3-D) structures. Several issues

Mattan Kamon; Nuno Alexandre Marques; Luis Miguel Silveira; Jacob White

1998-01-01

329

A simple model of EMI-induced timing jitter in digital circuits, its statistical distribution and its effect on circuit performance  

Microsoft Academic Search

A simple model has been developed to characterize electromagnetic interference induced timing variations (jitter) in digital circuits. The model is based on measurable switching parameters of logic gates, and requires no knowledge of the internal workings of a device. It correctly predicts not only the dependence of jitter on the amplitude, modulation depth and frequency of the interfering signal, but

Martin P. Robinson; Katharina Fischer; Ian D. Flintoft; Andrew C. Marvin

2003-01-01

330

Modeling of VLSI Circuits and Systems Instructor: Lei He  

E-print Network

-based modeling for high-speed signaling) #12;Some Details on hws Example 1: Matlab coding of PRIMA n Extend and electric vehicle), or any systems Background required Basics of IC and systems Matlab and SPICE (both could analysis for logic and on-chip interconnects n 1 hw (e.g., model order reduction in Matlab) Stochastic

He, Lei

331

Using electronic circuits to model simple neuroelectric interactions  

Microsoft Academic Search

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

E. R. Lewis

1968-01-01

332

New printed circuit boards magnetic coils in the vacuum vessel of J-TEXT tokamak for position measurement.  

PubMed

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. PMID:21033989

Qiu, S S; Zhuang, G; Zhang, M; Xia, D H; Rao, B; Zhang, X Q; Pan, Y; Gentle, K

2010-10-01

333

New printed circuit boards magnetic coils in the vacuum vessel of J-TEXT tokamak for position measurementa)  

NASA Astrophysics Data System (ADS)

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.

Qiu, S. S.; Zhuang, G.; Zhang, M.; Xia, D. H.; Rao, B.; Zhang, X. Q.; Pan, Y.; Gentle, K.

2010-10-01

334

Modeling the polysilicon depletion effect and its impact on submicrometer CMOS circuit performance  

Microsoft Academic Search

We present a physically based continuous analytical MOSFET model for submicrometer devices that includes polysilicon depletion effect. It is shown that simple modification to standard MOSFET circuit models is all that is needed to account for the polydepletion effect. The new model accurately predicts, both measured and 2-D simulated, I-V, and C-V characteristics of submicrometer MOSFET's with polydepletion effect over

Narain D. Arora; E. Rios; Cheng-Liang Huang

1995-01-01

335

Reliability-yield allocation for semiconductor integrated circuits: modeling and optimization  

E-print Network

: : : : : : : : : : : : : : : 17 III.1. Manufacturing Yield . . . . . . . . . . . . . . . . . . . 18 III.2. Reliability of Semiconductor Integrated Circuits . . . 19 III.3. Defect Size, Defect Density, and Critical Area . . . . . 22 III.4. Poisson and Negative Binomial Yield... : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 36 IV.1. System Architecture of a Typical Memory IC . . . . . 36 IV.2. Yield Model with Redundancy . . . . . . . . . . . . . 39 IV.3. Yield Model with Various Types of Failures . . . . . . 40 IV.4. Yield Model with ECC...

Ha, Chunghun

2005-11-01

336

An equivalent lumped-circuit model for on-chip symmetric intertwined transformer  

Microsoft Academic Search

A physics-based equivalent lumped-circuit model for on-chip symmetric intertwined transformer is presented in this paper. This model accurately predicts the skin effect and proximity effect of the primary and secondary coils inductors over a wide-frequency range using a ladder `4-element' structure, respectively. One transformer loop and two RC networks are used to model the substrate loss related to substrate eddy

Jin Kang; Lingling Sun; Jincai Wen; Mingfu Zhao

2009-01-01

337

CAD-oriented equivalent-circuit modeling of on-chip interconnects on lossy silicon substrate  

Microsoft Academic Search

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

Ji Zheng; Yeon-Chang Hahm; Vijai K. Tripathi; Andreas Weisshaar

2000-01-01

338

Circuit-oriented discrete-time modeling and simulation for switching converters  

NASA Astrophysics Data System (ADS)

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.

Hsiao, C. J.; Ridley, R. B.; Naitoh, H.; Lee, F. C.

339

Improved cement quality and grinding efficiency by means of closed mill circuit modeling  

E-print Network

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...

Mejeoumov, Gleb Gennadievich

2009-05-15

340

For diagnostic purposes, analog circuits may be qualitatively modeled as resistive networks. We demonstrate that  

E-print Network

with a semantics that enables us to model different classes of faults arising in analog circuits. The qualitative values adequately describe different effects that faults may have. Then we present a sound and complete explicitly represents a network's series-parallel-star structure as a tree (sps-tree). As a result

Hamburg,.Universität

341

Steam-circuit Model for the Compact Linear Fresnel Reflector , G. L. Morrison1  

E-print Network

, D. R. Mills2 , P. Le Lievre3 and M. Behnia1 1 School of Mechanical and Manufacturing, UniversitySteam-circuit Model for the Compact Linear Fresnel Reflector Prototype J. D. Pye1 , G. L. Morrison1 of New South Wales, NSW, 2052 2 School of Physics, University of Sydney, NSW 2006 3 Solar Heat and Power

342

Dynamic control of a central pattern generator circuit: a computational model of the snail feeding network  

E-print Network

­Huxley models, Lymnaea stagnalis Abstract Central pattern generators (CPGs) are networks underlying rhythmic to the rhythmogenic circuit. In the feeding system of the pond snail, Lymnaea stagnalis, the extrinsic slow oscillator the CPG-driven motor pattern underlying feeding in the pond snail, Lymnaea (Fig. 1). One type of cell

Feng, Jianfeng

343

Equivalent circuit model of traveling-wave maser slow-wave structures  

NASA Technical Reports Server (NTRS)

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.

Shell, J.

1991-01-01

344

Distributed equivalent-circuit model for traveling-wave FET design  

Microsoft Academic Search

Based on reliable theoretical results, a distributed MESFET model is developed. It consists of equivalent-circuit elements which can be evaluated directly from FET material constants and geometry. The deviations with respect to full-wave-analysis results are investigated and some applications are shown.

Wolfgang Heinrich

1987-01-01

345

Simple proof of equivalence between adiabatic quantum computation and the circuit model  

E-print Network

We prove the equivalence between adiabatic quantum computation and quantum computation in the circuit model. An explicit adiabatic computation procedure is given that generates a ground state from which the answer can be extracted. The amount of time needed is evaluated by computing the gap. We show that the procedure is computationally efficient.

Ari Mizel; Daniel A. Lidar; Morgan Mitchell

2006-09-08

346

An Equivalent Circuit Model for Vertical Comb Drive MEMS Optical Scanner Controlled by Pulse Width Modulation  

NASA Astrophysics Data System (ADS)

An equivalent circuit model for the resonant-type vertical comb-driven optical MEMS (micro electro mechanical system) scanner has been developed based on the simple extension of the parallel-plate model. Both the electrostatic torque and the induction charge models are interpreted by using the equation-defined nonlinear dependent current source on the electrical circuit simulator platform. A systematic procedure has been investigated to fit the analytical model with the experimental results by using fitting parameters including the damping coefficient, the suspension width, and the comb gap. The developed simulation model has been used to verify a new control scheme to tune the scanner's oscillation amplitude in resonance by means of the pulse-width modulation of voltage at a given pulse height; the result indicates the effective use of digital electronics for the comb-driven optical scanner.

Maruyama, Satoshi; Nakada, Muneki; Mita, Makoto; Takahashi, Takuya; Fujita, Hiroyuki; Toshiyoshi, Hiroshi

347

Predicting input impedance and efficiency of graphene reconfigurable dipoles using a simple circuit model  

E-print Network

An analytical circuit model able to predict the input impedance of reconfigurable graphene plasmonic dipoles is presented. A suitable definition of plasmonic characteristic impedance, employing natural currents, is used to for consistent modeling of the antenna-load connection in the circuit. In its purely analytical form, the model shows good agreement with full-wave simulations, and explains the remarkable tuning properties of graphene antennas. Furthermore, using a single full-wave simulation and scaling laws, additional parasitic elements can be determined for a vast parametric space, leading to very accurate modeling. Finally, we also show that the modeling approach allows fair estimation of radiation efficiency as well. The approach also applies to thin plasmonic antennas realized using noble metals or semiconductors.

Tamagnone, Michele

2014-01-01

348

Preventing Thermal Overloads in Transmission Circuits via Model Predictive Control  

Microsoft Academic Search

A special protection scheme (SPS) based on model predictive control (MPC) is proposed to mitigate thermal overloads in advance, and so avoid cascade line tripping. The controller aims to keep the temperatures of conductors below their admissible limits before local relays intervene and trip out the lines. This objective is carried out by properly coordinating different control actions available in

Juliano S. A. Carneiro; Luca Ferrarini

2010-01-01

349

Modeling and extraction of interconnect capacitances for multilayer VLSI circuits  

Microsoft Academic Search

structures using a 2-D capacitance simulator TDTL. These are then transformed into 3-D geometry. The resulting capacitance are found to be within 10% of both the measured data and 3-D simulations of structures that are prevalent in a typical chips. The models and their coefficients for different vertical profiles are stored in the capacitance extraction tool CUP, which is coupled

Narain D. Arora; Kartik V. Raol; Reinhard Schumann; Llanda M. Richardson

1996-01-01

350

RESEARCH ARTICLE Open Access Modeling suggests that gene circuit architecture  

E-print Network

variability in a bacterial persistence network Rachel S Koh and Mary J Dunlop* Abstract Background: Bacterial persistence is a non-inherited bet-hedging mechanism where a subpopulation of cells enters a dormant state of persistence events can be tuned. Results: We present a model of the regulatory network controlling the Hip

Dunlop, Mary

351

Olfactory Functions Scale with Circuit Restoration in a Rapidly Reversible Alzheimer's Disease Model  

PubMed Central

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

Cheng, Ning; Bai, Li; Steuer, Elizabeth

2013-01-01

352

Olfactory functions scale with circuit restoration in a rapidly reversible Alzheimer's disease model.  

PubMed

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

Cheng, Ning; Bai, Li; Steuer, Elizabeth; Belluscio, Leonardo

2013-07-24

353

Synthesis of the System Modeling and Signal Detecting Circuit of a Novel Vacuum Microelectronic Accelerometer  

PubMed Central

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

Li, Dongling; Wen, Zhiyu; Wen, Zhongquan; He, Xuefeng; Yang, Yinchuan; Shang, Zhengguo

2009-01-01

354

Proceedings of the 2nd FieldsMITACS Industrial Problem-Solving Workshop, 2008 Model Order Reduction for Electronic Circuits  

E-print Network

). must be connected to the circuit simulator, a reduced order model, which will allow for realisticProceedings of the 2nd Fields­MITACS Industrial Problem-Solving Workshop, 2008 Model Order Reduction for Electronic Circuits: Mathematical and Physical Approaches Problem Presenter: Wil Schilders

Shontz, Suzanne M.

355

Current Injected Equivalent Circuit Approach to Modeling of Switching DC-DC Converters in Discontinuous Inductor Conduction Mode  

Microsoft Academic Search

A new current injected equivalent circuit approach (CIECA) to modeling switching dc-dc converter power stages is developed, which starts with current injected approach, and results in a set of equations which describe completely input and output properties and an equivalent linear circuit model valid at small signal low frequency levels.

P. R. K. Chetty

1982-01-01

356

Physics based lumped element circuit model for nanosecond pulsed dielectric barrier discharges  

NASA Astrophysics Data System (ADS)

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.

Underwood, Thomas; Roy, Subrata; Glaz, Bryan

2013-02-01

357

Extraction of battery parameters of the equivalent circuit model using a multi-objective genetic algorithm  

NASA Astrophysics Data System (ADS)

A simple but reasonably accurate battery model is required for simulating the performance of electrical systems that employ a battery for example an electric vehicle, as well as for investigating their potential as an energy storage device. In this paper, a relatively simple equivalent circuit based model is employed for modeling the performance of a battery. A computer code utilizing a multi-objective genetic algorithm is developed for the purpose of extracting the battery performance parameters. The code is applied to several existing industrial batteries as well as to two recently proposed high performance batteries which are currently in early research and development stage. The results demonstrate that with the optimally extracted performance parameters, the equivalent circuit based battery model can accurately predict the performance of various batteries of different sizes, capacities, and materials. Several test cases demonstrate that the multi-objective genetic algorithm can serve as a robust and reliable tool for extracting the battery performance parameters.

Brand, Jonathan; Zhang, Zheming; Agarwal, Ramesh K.

2014-02-01

358

Calculation of Short-circuit Mechanical Strength for Powerformer  

Microsoft Academic Search

Initial conditions and the time corresponding to most serious states of short-circuit was got based on the T-model of power transformer. Considering the conditions to be voltage at primary winding, short-circuit forces of windings and turns for transformer were calculated with FEM coupling magnetic field and circuit method under the 2D symmetrical model. As the turn corresponding to max forces

Wang Shishan; Liu Zeyuan; Li Yanming; Guo Yinna; Gao Hong

2006-01-01

359

Alterations of brain circuits in Down syndrome murine models.  

PubMed

Trisomy 21, also referred to Down syndrome (DS), is the most common genetic cause of mental retardation, affecting 1 each 800-1000 newborn children all over the world. DS is a complex disease, determined by an extra copy of human chromosome 21 that causes an imbalanced gene dose effect. The syntenies that exist between mouse chromosomes 10, 16, and 17 and human chromosome 21 offer the opportunity for a genotype-phenotype correlation and several mouse models of DS have been developed to improve our knowledge about cognitive disabilities and brain alterations. We present here the different murine models available up to now and we discuss the neural alterations that have been described in these strains. The largest amount of studies involved the so called Ts65Dn mouse showing early alterations of nitrergic, noradrenergic and cholinergic systems at the level of the basal forebrain. Neurogenesis and spine formations are decreased in the hippocampus, as well as the whole size of the cerebellum and the number of granule cells. PMID:21946025

Gotti, Stefano; Caricati, Egidio; Panzica, GianCarlo

2011-12-01

360

A novel approach to the modeling of the indoor power line channel part I: circuit analysis and companion model  

Microsoft Academic Search

Multiconductor Transmission Line (MTL) theory is utilized here for modeling the transfer function of power cables in the indoor environment. This approach allows us to determine a circuit model that well characterizes the underlying physics of signal propagation over power-line (PL) cables and that also allows us to account for particular wiring practices common in residential and business environments. In

Thomas Banwell; Stefano Galli

2005-01-01

361

Modeling and magnetic measurements of TNK synchrotron radiation source magnets  

NASA Astrophysics Data System (ADS)

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.

Belokrinitsky, S.; Churkin, I.; Oleynik, A.; Pekshev, D.; Philipchenko, A.; Rouvinsky, I.; Steshov, A.; Ushakov, V.

2009-05-01

362

Capnography and the bain circuit II: Validation of a computer model  

Microsoft Academic Search

Validation of a computer model is described. The behavior of this model is compared both with mechanical ventilation of a\\u000a test lung in a laboratory setup that uses a washout method and with manual ventilation. A comparison is also made with results\\u000a obtained from a volunteer breathing spontaneously through a Bain circuit and with results published in the literature. This

Jan E. W. Beneken; Nikolaus Gravenstein; Samsun Lampotang; Jan J. van der Aa; Joachim S. Gravenstein

1987-01-01

363

An accurate AC characteristic table look-up model for VLSI analog circuit simulation applications  

Microsoft Academic Search

A new accurate table look-up method is presented for modeling both I-V characteristics and C-V and\\/or Q-V characteristics of deep submicron MOSFETs for VLSI analog circuit simulation. Based on the linear and quadratic isoparametric shape functions, the proposed table lookup approach can accurately model complicated AC characteristics of MOSFETs. The charges and capacitances derived through integration of C-V characteristics and

D.-H. Cho; S. M. Kang

1993-01-01

364

Equivalent Circuit Model for Thick Split Ring Resonators and Thick Spiral Resonators  

E-print Network

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.

Mancera, Laura Maria Pulido

2014-01-01

365

Frequency-independent equivalent-circuit model for on-chip spiral inductors  

Microsoft Academic Search

A wide-band, physical and scalable 2-? equivalent circuit model for on-chip spiral inductors is developed. Using fre- quency-independent RLC elements, it accurately captures R(f) and L(f) characteristics beyond the self-resonant fre- quency. This new model is fully compatible with both AC and transient analysis. Verification with measurement data demonstrates excellent scalability for a wide range of induc- tor configurations.

Yu Cao; Robert A. Groves; D. Zamdmer; Jean-Olivier Plouchart; Richard A. Wachnik; Xuejue Huang; Chenming Hu

2003-01-01

366

An accurate equivalent circuit model of flip chip and via interconnects  

Microsoft Academic Search

In this paper, the transition discontinuities of flip chip circuits are modeled and investigated using finite-difference time-domain (FDTD) method to predict the S-parameters of different packages. This includes transition between two coplanar lines on the chip and mother board and transition between two striplines in a package. The computed S-parameter of the flip chip package using the FDTD model are

H. H. M. Ghouz; E.-B. El-Sharawy

1996-01-01

367

Magnetic properties modeling of soft magnetic composite materials using two-dimensional vector hybrid hysteresis model  

NASA Astrophysics Data System (ADS)

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.

Li, Dandan; Liu, Fugui; Li, Yongjian; Zhao, Zhigang; Zhang, Changgeng; Yang, Qingxin

2014-05-01

368

Comparison of the AWA lumped-circuit model of electrical discharges with empirical data  

SciTech Connect

The authors compare experimental data for three 1.7-m-long transient discharges with an AWA lumped- circuit discharge model in which the arc resistance is taken from the Arc Welder's Ansatz, R{sub a} = V*/{vert bar}I {vert bar}, where V* is a positive constant and I is the discharge current. In addition to the arc resistance, there is a small series resistance R present in the external circuit. A single value for each of R and V* is deduced from the data, and these values are used to characterize all three discharges. Adequate agreement with the experimental data is obtained; for example, the authors predict the proper number of current reversals for each discharge and abrupt termination of current flow after a finite time. The authors suggest that the AWA lumped circuit provides a better representation of the data than a standard lumped-circuit RLC model and hence is more useful as a tool for prediction and interpretation of discharges.

Maier, W.B. II; Kadish, A. (Los Alamos National Lab., NM (USA)); Robiscoe, R.T. (Montana State Univ., Bozeman, MT (USA). Dept. of Physics)

1990-12-01

369

Magnetic modeling of the Bushveld Igneous Complex  

Microsoft Academic Search

Magnetic modeling of the 2.06 Ga Bushveld Complex presents special challenges due a variety of magnetic effects. These include strong remanence in the Main Zone and extremely high magnetic susceptibilities in the Upper Zone, which exhibit self-demagnetization. Recent palaeomagnetic results have resolved a long standing discrepancy between age data, which constrain the emplacement to within 1 million years, and older

S. J. Webb; J. Cole; S. A. Letts; C. Finn; T. H. Torsvik; M. D. Lee

2009-01-01

370

A circuital approach to estimate the magnetic field reduction of nonferrous metal shields  

Microsoft Academic Search

The reduction of magnetic fields is a topic of concern to the electric utility industry and the electromagnetic compatibility community. One technique to reduce the magnetic fields is to use metal plates and enclosures for shielding, in addition, knowledge or the loading effect of a conducting structure in close proximity to power cables is needed for estimating power loss. Until

William M. Frix; George G. Karady

1997-01-01

371

Magnetic field and equivalent circuit of induction motors with shielded poles  

Microsoft Academic Search

The magnetic field distribution in the air gap of induction motors with shielded poles is calculated, taking into account forward and backward harmonics as well as their skew. An analysis is made on the basis of theoretically or experimentally determined magnetic induction (flux density) rather than by the method of symmetrical components. Measurements were made with a search coil along

V. I. Katkyavichyus; I. V. Bukshnaytis; D. K. Banite

1984-01-01

372

A Classical Switched LC/LR Circuit Modeling the Quantum Zeno and Anti-Zeno Effects  

E-print Network

Generalizing a recent analysis, we model the quantum Zeno and anti-Zeno effects with a quickly switched, ideal LC/LR circuit, in the limiting case of it alternating very many times between its short LC and even shorter LR regime. If the initial current is arranged to be negligible, the capacitor turns out never to discharge. If the initial current is made dominant, this capacitor discharges, and faster than the exponential decay to which it limits. The existence and simplicity of these phases in such a rudimentary model indicates that the corresponding effects are ubiquitous throughout physics, both quantum and classical. In turn, the parameter space of this model contains intermediate phases in which the circuit exhibits behaviors that seem to foreshadow other quantum effects of some interest.

T. Hubsch; V. Pankovic

2009-07-24

373

Analytical model for permanent magnet motors with surface mounted magnets  

Microsoft Academic Search

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

A. B. Proca; A. Keyhani; A. El-Antably; Wenzhe Lu; Min Dai

2003-01-01

374

Compact Modeling of Nonlinear Analog Circuits using System Identification via Semi-Definite Programming and Robustness Certification  

E-print Network

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 ...

Bond, Bradley N.

375

Eddy-Current Type Proximity Sensor With Closed Magnetic Circuit Geometry  

Microsoft Academic Search

The eddy-current type proximity sensor is a noncontact type sensing device to detect the approach of a conductor by increase of coil resistance due to eddy-current loss. This paper proposes to add the cap-shaped magnetic flux shield at the top of the ferrite core for the actual sensor. In conventional proximity sensors, main magnetic flux path passes through the air

Koichi Koibuchi; Koichiro Sawa; Takashi Honma; Takumi Hayashi; Kuniyoshi Ueda; Hiroshi Sasaki

2007-01-01

376

Development of an equivalent circuit model of a fuel cell to evaluate the effects of inverter ripple current  

Microsoft Academic Search

In this paper an impedance model of the proton exchange membrane fuel cell stack (PEMFCS) is proposed. The proposed study employs an equivalent circuit of the PEMFCS derived by frequency response analysis (FRA) technique. An equivalent circuit for the fuel cell stack is developed to evaluate the effects of ripple currents generated by the power-conditioning unit. The calculated results are

Woojin Choi; Prasad N. Enjeti; Jo W. Howze

2004-01-01

377

A delay-dependent stability criterion of neutral systems and its application to a partial element equivalent circuit model  

Microsoft Academic Search

The real circuit model, such as a partial element equivalent circuit (PEEC), can be represented as a delay differential equation (DDE) of neutral type. The study of asymptotic stability of this kind of systems is of much importance due to the fragility of DDE solvers. Based on a descriptor system approach, new delay-dependent stability results are derived by introducing some

Dong Yue; Qing-Long Han

2004-01-01

378

The Circuit Theory Behind Coupled-Mode Magnetic Resonance-Based Wireless Power Transmission  

PubMed Central

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

Kiani, Mehdi; Ghovanloo, Maysam

2014-01-01

379

Accurate Cold-Test Model of Helical TWT Slow-Wave Circuits  

NASA Technical Reports Server (NTRS)

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.

Kory, Carol L.; Dayton, James A., Jr.

1997-01-01

380

Accurate Cold-Test Model of Helical TWT Slow-Wave Circuits  

NASA Technical Reports Server (NTRS)

Recently, a method has been established to accurately calculate cold-test data for helical slow-wave structures using the three-dimensional (3-D) 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.

Kory, Carol L.; Dayton, J. A., Jr.

1998-01-01

381

Loss Current Analysis of Water Tree Degradation in Polyethylene using Equivalent Circuit Model  

NASA Astrophysics Data System (ADS)

It is well known that the degradation of XLPE cable by water tree gives rise to harmonics in the loss current. Many researches by simulation and experiment have been carried out for the purpose of the elucidation of the mechanism of the harmonics in the loss current generation. In the present study, the loss current was calculated from the equivalent circuit model composed of voltage-dependent resistance and condenser. These elements are being connected with the matrix state. As a result, we were able to obtain the good agreement between the experimental value and the calculated value by appropriately choosing the characteristics of the voltage-dependent resistance. The equivalent circuit model determined in this study can consider not only the electrical characteristic of water tree but also its shape.

Suzuki, Masafumi; Itoh, Atsushi; Yoshimura, Noboru

382

Circuit model optimization of a nano split ring resonator dimer antenna operating in infrared spectral range  

NASA Astrophysics Data System (ADS)

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.

Gneiding, N.; Zhuromskyy, O.; Shamonina, E.; Peschel, U.

2014-10-01

383

A system-level circuit model for multi- and single-chip CPUs  

Microsoft Academic Search

This report will detail a system level circuit model that has been used to predict the performance of microprocessors, gate arrays, and mainframe computers implemented in several IC technologies. Comparisons have been made on the basis of clock frequency, power dissipation and chip\\/module sizes. Predictions indicate that in ten years a 0.7?m CMOS micro-processor with 6-million transistors will execute 30-60

H. B. BakoglufX; J. D. Meindl

1987-01-01

384

Efficient SAT-based unbounded symbolic model checking using circuit cofactoring  

Microsoft Academic Search

We describe an efficient approach for SAT-based quantifier elimination that significantly improves the performance of pre-image and fixed-point computation in SAT-based unbounded symbolic model checking (UMC). The proposed method captures a larger set of new states per SAT-based enumeration step during quantifier elimination, in comparison to previous approaches. The novelty of our approach is in the use of circuit-based cofactoring

Malay K Ganai; Aarti Gupta; Pranav Ashar

2004-01-01

385

Efficient SAT-based unbounded symbolic model checking using circuit cofactoring  

Microsoft Academic Search

We describe an efficient approach for SAT-based quantifier elimination that significantly improves the performance of pre- image and fixed-point computation in SAT-based unbounded symbolic model checking (UMC). The proposed method captures a larger set of new states per SAT-based enumeration step during quantifier elimination, in comparison to previous approaches. The novelty of our approach is in the use of circuit-based

Malay K. Ganai; Aarti Gupta; Pranav Ashar

2004-01-01

386

A circuit-compatible model of ballistic carbon nanotube field-effect transistors  

Microsoft Academic Search

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

Arijit Raychowdhury; Saibal Mukhopadhyay; Kaushik Roy

2004-01-01

387

Efficient passive circuit models for distributed networks with frequency-dependent parameters  

Microsoft Academic Search

This paper presents an efficient method for the analysis of multiconductor transmission lines with frequency-dependent parameters. The proposed technique generates positive-real representations for the frequency dependency of transmission line parameters as well as closed-form expressions based on exponential Pade approximants. The new model is suitable for inclusion in general purpose circuit simulators and overcomes the difficulty of mixed frequency\\/time simulation

Anestis Dounavis; Ramachandra Achar; Michel S. Nakhla

2000-01-01

388

Comprehensive Compact Models for the Circuit Simulation of Multichip Power Modules  

Microsoft Academic Search

This paper proposes the model development of a packaged semiconductor power module, for use in a circuit simulation environment. Focusing on railway traction applications, it considers a state-of-the-art 6.5 kV insulated gate bipolar transistor (IGBT) module, taking into account the antiparallel connection of IGBTs and free-wheeling diodes, and including all main electrothermal and electromagnetic effects associated with the multichip structure.

Alberto Castellazzi

2010-01-01

389

Magnetic network model including loss separation and Preisach principles for the evaluation of core losses in devices  

NASA Astrophysics Data System (ADS)

In this paper, a method is developed to calculate the core loss in a switched reluctance machine. The magnetic circuit of the motor is described as a magnetic network. The electromagnetic behavior of each magnetic network element takes into account the iron loss using the Preisach model and the principle of loss separation. Using the numerical routines, the local core loss in the different motor sections is calculated. The global core loss is compared with the experimentally determined core loss.

Dupré, Luc; Sergeant, Peter; Vandenbossche, Lode

2005-05-01

390

Magnetic-bubble conservative logic  

Microsoft Academic Search

Among integrated-circuit devices, magnetic bubbles are a particularly interesting candidate to implement the Fredkin gate and conservative logic. The magnetostatic repulsion of magnetic bubbles simulates the bouncing-ball model of conservative logic.

Hsu Chang

1982-01-01

391

Model and simulation of a flywheel energy storage system at a utility substation using electro-magnetic transients programs  

SciTech Connect

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.

Weissbach, R.S.; Karady, G.G.; Farmer, R.G. [Arizona State Univ., Tempe, AZ (United States)

1996-11-01

392

The interplay of plasticity and adaptation in neural circuits: a generative model  

PubMed Central

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.

Bernacchia, Alberto

2014-01-01

393

Bipolar junction transistor models for circuit simulation of cosmic-ray-induced soft errors  

NASA Technical Reports Server (NTRS)

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.

Benumof, R.; Zoutendyk, J.

1984-01-01

394

Large Signal Circuit Model of Two-Section Gain Lever Quantum Dot Laser  

NASA Astrophysics Data System (ADS)

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.

Ashkan, Horri; Seyedeh Zahra, Mirmoeini; Rahim, Faez

2012-11-01

395

Simple calculation method of the magnetic field from double-circuit twisted three-phase cables as a tool for fault detection  

Microsoft Academic Search

This paper proposes a simple innovative formula for the calculation of the magnetic field generated by a single and a double circuit twisted three-phase power cable line. The formula results a good approximation of the rigorous analytical one and at the same time is much more accurate than the approximated formula found in literature, as demonstrated by the case of

G. Mazzanti; M. Landini; E. Kandia; L. Sandrolini

2011-01-01

396

Quantitative modeling and optimization of magnetic tweezers.  

PubMed

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 law. For complicated geometries and in the presence of an iron yoke, we employ a finite-element three-dimensional PDE solver to numerically solve the magnetostatic problem. The theoretical predictions are in quantitative agreement with direct Hall-probe measurements of the magnetic field and with measurements of the force exerted on DNA-tethered beads. Using these predictive theories, we systematically explore the effects of magnet alignment, magnet spacing, magnet size, and of adding an iron yoke to the magnets on the forces that can be exerted on tethered particles. We find that the optimal configuration for maximal stretching forces is a vertically aligned pair of magnets, with a minimal gap between the magnets and minimal flow cell thickness. Following these principles, we present a configuration that allows one to apply > or = 40 pN stretching forces on approximately 1-microm tethered beads. PMID:19527664

Lipfert, Jan; Hao, Xiaomin; Dekker, Nynke H

2009-06-17

397

Quantitative Modeling and Optimization of Magnetic Tweezers  

PubMed Central

Abstract 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 law. For complicated geometries and in the presence of an iron yoke, we employ a finite-element three-dimensional PDE solver to numerically solve the magnetostatic problem. The theoretical predictions are in quantitative agreement with direct Hall-probe measurements of the magnetic field and with measurements of the force exerted on DNA-tethered beads. Using these predictive theories, we systematically explore the effects of magnet alignment, magnet spacing, magnet size, and of adding an iron yoke to the magnets on the forces that can be exerted on tethered particles. We find that the optimal configuration for maximal stretching forces is a vertically aligned pair of magnets, with a minimal gap between the magnets and minimal flow cell thickness. Following these principles, we present a configuration that allows one to apply ?40 pN stretching forces on ?1-?m tethered beads. PMID:19527664

Lipfert, Jan; Hao, Xiaomin; Dekker, Nynke H.

2009-01-01

398

Functional Connectivity in fMRI: A Modeling Approach for Estimation and for Relating to Local Circuits  

PubMed Central

Although progress has been made in relating neuronal events to changes in brain metabolism and blood flow, the interpretation of functional neuroimaging data in terms of the underlying brain circuits is still poorly understood. Computational modeling of connection patterns both among and within regions can be helpful in this interpretation. We present a neural network model of the ventral visual pathway and its relevant functional connections. This includes a new learning method that adjusts the magnitude of interregional connections in order to match experimental results of an arbitrary functional magnetic resonance imaging (fMRI) data set. We demonstrate that this method finds the appropriate connection strengths when trained on a model system with known, randomly chosen connection weights. We then use the method for examining fMRI results from a one-back matching task in human subjects, both healthy and those with schizophrenia. The results discovered by the learning method support previous findings of a disconnection between left temporal and frontal cortices in the group with schizophrenia, and a concomitant increase of right-sided temporo-frontal connection strengths. We then demonstrate that the disconnection may be explained by reduced local recurrent circuitry in frontal cortex. This method extends currently available methods for estimating functional connectivity from human imaging data by including both local circuits and features of inter-regional connections, such as topography and sparseness, in addition to total connection strengths. Furthermore, our results suggest how fronto-temporal functional disconnection in schizophrenia can result from reduced local synaptic connections within frontal cortex rather than compromised inter-regional connections. PMID:17134917

Winder, Ransom; Cortes, Carlos R.; Reggia, James A.; Tagamets, M-A.

2007-01-01

399

Initial results of a global circuit model with variable stratospheric and tropospheric aerosols  

NASA Astrophysics Data System (ADS)

A new model of the global circuit has been constructed that treats more realistically than previous models the external influences due to varying charged particle fluxes from space, the internal variability due to the transport of radon by atmospheric dynamics, and the varying aerosol populations. An approximate treatment of the effects of explosive volcanic eruptions, that introduce SO2 and H2O into the stratosphere, involves the creation of ultrafine aerosol particles in the downward branch of the Brewer-Dobson circulation from sulfuric acid aerosol particles vaporized in the upward branch. A large increase in stratospheric column resistance occurs at high latitudes, but for much of the time this column resistance is reduced by stratospheric ionizing radiation due to relativistic electron precipitation. Here we present results for the variability of the global circuit due to the variations of the aerosol populations in the stratosphere and troposphere, the variability of the cosmic ray flux, and the geographical and seasonal variability of the near-surface radioactivity. We discuss inferred changes in the circuit parameters associated with climate change, on interannual to Milankovich timescales.

Tinsley, Brian A.; Zhou, Limin

2006-08-01

400

Circuit modeling and performance analysis of SWCNT bundle 3D interconnects  

NASA Astrophysics Data System (ADS)

Metallic carbon nanotubes (CNTs) have been proposed as a promising alternative to Cu interconnects in future integrated circuits (ICs) for their remarkable conductive, mechanical and thermal properties. Compact equivalent circuit models for single-walled carbon nanotube (SWCNT) bundles are described, and the performance of SWCNT bundle interconnects is evaluated and compared with traditional Cu interconnects at different interconnect levels for through-silicon-via-based three dimensional (3D) ICs. It is shown that at a local level, CNT interconnects exhibit lower signal delay and smaller optimal wire size. At intermediate and global levels, the delay improvement becomes more significant with technology scaling and increasing wire lengths. For 1 mm intermediate and 10 mm global level interconnects, the delay of SWCNT bundles is only 49.49% and 52.82% that of the Cu wires, respectively.

Libo, Qian; Zhangming, Zhu; Ruixue, Ding; Yintang, Yang

2013-09-01

401

Analytical dynamic modeling of a cantilever IPMC actuator based on a distributed electrical circuit  

NASA Astrophysics Data System (ADS)

Ionic polymer-metal composite (IPMC) has a wide range of applications in robotics, biomedical devices and artificial muscles. The modeling of the IPMC actuator is a multi-physics task as it involves electricity, chemistry, dynamics and control. Due to its complexity and its nonlinearity, IPMC modeling is difficult and its behavior is still not fully agreed upon by researchers. In this paper, a dynamic model of a cantilever IPMC actuator based on a distributed RC electrical circuit is developed. The RC transmission line theory is used to derive the simple analytical impedance and actuation model of an IPMC actuator. This method permits us to identify the current and voltage as functions of polymer length and frequency. First, an infinite-dimensional impedance model is developed and then replaced with a simple second-order electro-mechanical model using the Golubev method. The proposed modeling approach is validated using existing experimental data.

Moeinkhah, Hossein; Rezaeepazhand, Jalil; Akbarzadeh, Alireza

2013-05-01

402

Parametric, nonparametric and parametric modelling of a chaotic circuit time series  

E-print Network

The determination of a differential equation underlying a measured time series is a frequently arising task in nonlinear time series analysis. In the validation of a proposed model one often faces the dilemma that it is hard to decide whether possible discrepancies between the time series and model output are caused by an inappropriate model or by bad estimates of parameters in a correct type of model, or both. We propose a combination of parametric modelling based on Bock's multiple shooting algorithm and nonparametric modelling based on optimal transformations as a strategy to test proposed models and if rejected suggest and test new ones. We exemplify this strategy on an experimental time series from a chaotic circuit where we obtain an extremely accurate reconstruction of the observed attractor.

J. Timmer; H. Rust; W. Horbelt; H. U. Voss

2000-09-19

403

A joint field\\/circuit model of line-to-ring coupling structures and its application to the design of microstrip dual-mode filters and ring resonator circuits  

Microsoft Academic Search

A joint field\\/circuit model is proposed in this paper to characterize a class of line-to-ring coupling structures for design and optimization of microstrip dual-mode filters and ring resonator circuits. The generic model is derived from field theory and presented in terms of circuit elements by applying a newly developed numerical deembedding technique called “short-open calibration” in a deterministic method-of-moments scheme.

Lei Zhu; Ke Wu

1999-01-01

404

Magnetic field screening effect in electroweak model  

E-print Network

It is shown that in the Weinberg-Salam model a magnetic field screening effect for static magnetic solutions takes place. The origin of that phenomenon is conditioned by features of the electro-weak interaction, namely, there is mutual cancellation of Abelian magnetic fields created by the SU(2) gauge fields and Higgs boson. The effect implies monopole charge screening in finite energy system of monopoles and antimonopoles. We consider another manifestation of the screening effect which leads to an essential energy decrease of magnetic solutions. Applying variational method we have found a magnetic field configuration with a topological azimuthal magnetic flux which minimizes the energy functional and possesses a total energy of order 1 TeV. We suppose that corresponding magnetic bound state exists in the electroweak theory and can be detected in experiment.

Bakry, A; Zhang, P M; Zou, L P

2014-01-01

405

Self-Organization of Polarized Cell Signaling via Autocrine Circuits: Computational Model Analysis  

SciTech Connect

Recent studies have suggested that autocine signaling through epidermal growth factor receptor (EGFR) might be involved in generating or maintaining an intrinsic polarity in tissue cells, possibly via spatial localization of EGFR-mediated signaling. The difficulty of experimental investigation of autocrine signaling makes especially valuable an application of computational modeling for critical hypotheses about the dynamic operation of the underlying signaling circuits, both intracellular and extracellular. Toward this end, we develop and analyze here a spatially distributed dynamic computational model of autocrine EGFR signaling.

Maly, Ivan V.; Wiley, H S.; Lauffenburger, Douglas A.

2004-01-31

406

Fault modeling, delay evaluation and path selection for delay test under process variation in nano-scale VLSI circuits  

E-print Network

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, variational delay evaluation...

Lu, Xiang

2006-04-12

407

Strategy Levels for Guiding Discussion to Promote Explanatory Model Construction in Circuit Electricity  

NSDL National Science Digital Library

A framework for describing and tracking the whole-class discussion-based teaching strategies used by a teacher to support students' construction and development of explanatory models for concepts in circuit electricity is described. A new type of diagram developed to portray teacher-student discourse patterns facilitated the identification of two distinct types, or levels, of teaching strategies: 1) those that support dialogical or conversational elements of classroom interaction; and 2) those that support cognitive model construction processes. The latter include the higher-level goals of promoting a cycle of Observation, model Generation, model Evaluation, and model Modification. While previous studies have focused primarily on the dialogical strategies that are essential for fostering communication as an enabling condition, the cognitive strategies identified herein are aimed at fostering conceptual model construction.

Williams, E. G.; Clement, John J.

2007-11-25

408

Influence of micro-channel shape and magnetic material on the magneto-refrigeration process of integrated circuits.  

PubMed

We developed a two dimensional transient numerical model that solves the first step of heat transfer of an active magnetic regenerative refrigerator (AMR) using the heat conduction equation for an adiabatic system. For micro-refrigeration, an AMR device is constituted by a magnetic material, placed on a silicon wafer containing micro-channels where a heat exchanging fluid flows. The magnetic materials used in the simulations are the promising the Gd5Si2Ge2, La(Fe0.88Si0.22)13 and La0.66Sr0.33MnO3 compounds, because they exhibit a giant magnetocaloric effect near room temperature. We considered different initial conditions, namely different micro-channel shapes, sizes and separations, aiming to increase the performance of the micro-cooler device. The influence of the thickness of the magnetic material on refrigeration power is also studied. PMID:20355468

Pereira, A M; Soares, J C; Ventura, J; Sousa, J B; Araujo, J P; Oliveira, J C R E

2010-04-01

409

A GLOBAL MAGNETIC TOPOLOGY MODEL FOR MAGNETIC CLOUDS. II  

SciTech Connect

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.

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

410

Chiral magnetic effect in the PNJL model  

E-print Network

We study the two-flavor Nambu--Jona-Lasinio model with the Polyakov loop (PNJL model) in the presence of a strong magnetic field and a chiral chemical potential $\\mu_5$ which mimics the effect of imbalanced chirality due to QCD instanton and/or sphaleron transitions. Firstly we focus on the properties of chiral symmetry breaking and deconfinement crossover under the strong magnetic field. Then we discuss the role of $\\mu_5$ on the phase structure. Finally the chirality charge, electric current, and their susceptibility, which are relevant to the Chiral Magnetic Effect, are computed in the model.

Kenji Fukushima; Marco Ruggieri; Raoul Gatto

2010-02-27

411

Nuclear Bag Model and Nuclear Magnetic Moments  

E-print Network

In 1991, we proposed a model in which nucleus is treated as a spherical symmetric MIT bag and nucleon satisfies the MIT bag model boundary condition. The model was employed to calculate nuclear magnetic moments. The results are in good agreement with experiment data. Now, we found this model is still interesting and illuminating.

Liang-gang Liu

1999-03-31

412

A wideband lumped circuit model of the terminal and internal electromagnetic response of rotating machine windings with a coaxial insulation system  

Microsoft Academic Search

The polyphase model can be used to simulate the terminal and internal electromagnetic response of, for example, Powerformer™: a new power generator. The circuit parameters are based on geometrical and material data. The slot leakage is modeled by means of a reluctance circuit, which is coupled to the electric circuit by means of winding templates. The capacitive current and its

Pär Holmberg; Mats Leijon; Stefan Johansson

2004-01-01

413

Unified equivalent-circuit model of planar discontinuities suitable for field theory-based CAD and optimization of M(H)MIC's  

Microsoft Academic Search

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

Lei Zhu; Ke Wu

1999-01-01

414

Modeling and optimization of permanent magnetic motors  

E-print Network

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 ...

Pinkham, Andrew P

2008-01-01

415

Transcranial Magnetic Stimulation: Modelling and New Techniques.  

National Technical Information Service (NTIS)

The aim of this thesis was to develop physical understanding of magnetic stimulation and to build models that could provide new insights for utilizing the technique. For this purpose, two principal issues had to be addressed: (1) macroscopic electromagnet...

J. Ruohonen

1998-01-01

416

Capacitive Stress Gauges in Model Dipole Magnets  

E-print Network

of weighted capacitance. Though the offsets to capacitance due to a heating cycle may be unpredictable, convergence of weighted capacitance values over several heat cycles can certainly reduce error in model magnet stress measurements....

Ragland, R. Blake

2009-06-09

417

A lumped-circuit model for the radiation impedance of a circular piston in a rigid baffle.  

PubMed

The radiation impedance of a piston transducer mounted in a rigid baffle has been widely addressed in the literature. The real and imaginary parts of the impedance are described by the first order Bessel and Struve functions, respectively. Although there are power series expansions for both functions, the analytic formulation of a lumped circuit is not trivial. In this paper, we present an empirical approach to the derivation of a lumped-circuit model for the radiation impedance expression, based on observations on the near-field behavior of stored kinetic and elastic energy. The field analysis is carried out using a finite element method model of the piston and surrounding fluid medium. We show that fluctuations in the real and imaginary components of the impedance can be modeled by series and shunt tank circuits, each of which shape a certain section of the impedance curve. Because the model is composed of lumped-circuit elements, it can be used in circuit simulators. Consequently, the proposed model is useful for the analysis of transducer front-end circuits. PMID:18986901

Bozkurt, Ayhan

2008-09-01

418

Magnetic field decay in model SSC dipoles  

SciTech Connect

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.

Gilbert, W.S.; Althaus, R.F.; Barale, P.J.; Benjegerdes, R.W.; Green, M.A.; Green, M.I.; Scanlan, R.M.

1988-08-01

419

Impaired activity-dependent neural circuit assembly and refinement in autism spectrum disorder genetic models  

PubMed Central

Early-use activity during circuit-specific critical periods refines brain circuitry by the coupled processes of eliminating inappropriate synapses and strengthening maintained synapses. We theorize these activity-dependent (A-D) developmental processes are specifically impaired in autism spectrum disorders (ASDs). ASD genetic models in both mouse and Drosophila have pioneered our insights into normal A-D neural circuit assembly and consolidation, and how these developmental mechanisms go awry in specific genetic conditions. The monogenic fragile X syndrome (FXS), a common cause of heritable ASD and intellectual disability, has been particularly well linked to defects in A-D critical period processes. The fragile X mental retardation protein (FMRP) is positively activity-regulated in expression and function, in turn regulates excitability and activity in a negative feedback loop, and appears to be required for the A-D remodeling of synaptic connectivity during early-use critical periods. The Drosophila FXS model has been shown to functionally conserve the roles of human FMRP in synaptogenesis, and has been centrally important in generating our current mechanistic understanding of the FXS disease state. Recent advances in Drosophila optogenetics, transgenic calcium reporters, highly-targeted transgenic drivers for individually-identified neurons, and a vastly improved connectome of the brain are now being combined to provide unparalleled opportunities to both manipulate and monitor A-D processes during critical period brain development in defined neural circuits. The field is now poised to exploit this new Drosophila transgenic toolbox for the systematic dissection of A-D mechanisms in normal versus ASD brain development, particularly utilizing the well-established Drosophila FXS disease model. PMID:24570656

Doll, Caleb A.; Broadie, Kendal

2014-01-01

420

Design and analysis of perfect terahertz metamaterial absorber by a novel dynamic circuit model.  

PubMed

Metamaterial terahertz absorbers composed of a frequency selective layer followed by a spacer and a metallic backplane have recently attracted great attention as a device to detect terahertz radiation. In this work, we present a quasistatic dynamic circuit model that can decently describe operational principle of metamaterial terahertz absorbers based on interference theory of reflected waves. The model comprises two series LC resonance components, one for resonance in frequency selective surface (FSS) and another for resonance inside the spacer. Absorption frequency is dominantly determined by the LC of FSS while the spacer LC changes slightly the magnitude and frequency of absorption. This model fits perfectly for both simulated and experimental data. By using this model, we study our designed absorber and we analyze the effect of changing in spacer thickness and metal conductivity on absorption spectrum. PMID:23938496

Hokmabadi, Mohammad Parvinnezhad; Wilbert, David S; Kung, Patrick; Kim, Seongsin M

2013-07-15

421

Elevated inflammatory mediators and pulmonary hypertension after applying an extracorporeal circuit in a neonatal sepsis model  

Microsoft Academic Search

Purpose  We aimed to study the changes in cytokines, oxidative mediators, and pulmonary blood pressure in a neonatal sepsis model when\\u000a applying an extracorporeal circuit (ECC).\\u000a \\u000a \\u000a \\u000a \\u000a Methods  Of 28 anesthetized and mechanically ventilated 3-day-old piglets, 14 underwent cecal ligation and perforation (CLP), of which\\u000a 7 underwent ECC for 3 h from 3 to 6 h after CLP. The remaining 14 were sham, of which

Mohamed Hamed Hussein; Ghada Abdel-Hamid Daoud; Takashi Hashimoto

2011-01-01

422

Vector spin modeling for magnetic tunnel junctions with voltage dependent effects  

NASA Astrophysics Data System (ADS)

Integration and co-design of CMOS and spin transfer devices requires accurate vector spin conduction modeling of magnetic tunnel junction (MTJ) devices. A physically realistic model of the MTJ should comprehend the spin torque dynamics of nanomagnet interacting with an injected vector spin current and the voltage dependent spin torque. Vector spin modeling allows for calculation of 3 component spin currents and potentials along with the charge currents/potentials in non-collinear magnetic systems. Here, we show 4-component vector spin conduction modeling of magnetic tunnel junction devices coupled with spin transfer torque in the nanomagnet. Nanomagnet dynamics, voltage dependent spin transport, and thermal noise are comprehended in a self-consistent fashion. We show comparison of the model with experimental magnetoresistance (MR) of MTJs and voltage degradation of MR with voltage. Proposed model enables MTJ circuit design that comprehends voltage dependent spin torque effects, switching error rates, spin degradation, and back hopping effects.

Manipatruni, Sasikanth; Nikonov, Dmitri E.; Young, Ian A.

2014-05-01

423

Approaches for modeling magnetic nanoparticle dynamics.  

PubMed

Magnetic nanoparticles are useful biological probes as well as therapeutic agents. Several approaches have been used to model nanoparticle magnetization dynamics for both Brownian as well as Neel rotation. Magnetizations are often of interest and can be compared with experimental results. Here we summarize these approaches, including the Stoner-Wohlfarth approach and stochastic approaches including thermal fluctuations. Non-equilibrium-related temperature effects can be described by a distribution function approach (Fokker-Planck equation) or a stochastic differential equation (Langevin equation). Approximate models in several regimes can be derived from these general approaches to simplify implementation. PMID:25271360

Reeves, Daniel B; Weaver, John B

2014-01-01

424

An improved electrical and thermal model of a microbolometer for electronic circuit simulation  

NASA Astrophysics Data System (ADS)

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.

Würfel, D.; Vogt, H.

2012-09-01

425

Modeling of non-uniform device geometries for post-lithography circuit analysis  

NASA Astrophysics Data System (ADS)

Current ORC and LRC tools are not connected to design in any way. They are pure shape-based functions. A wafer-shape based power and performance signoff is desirable for RET validation as well as for "closest-to-silicon" analysis. The printed images (generated by lithography simulation) are not restricted to simple rectilinear geometries. There may be other sources of such irregularities such as Line Edge Roughness (LER). For instance, a silicon image of a transistor may not be a perfect rectangle as is assumed by all current circuit analysis tools. Existing tools and device models cannot handle complicated non-rectilinear geometries. In this paper, we present a novel technique to model non-uniform, non-rectilinear gates as equivalent perfect rectangle gates so that they can be analyzed by SPICE-like circuit analysis tools. The effect of threshold voltage variation along the width of the device is shown to be significant and is modeled accurately. Taking this effect into account, we find the current density at every point along the device and integrate it to obtain the total current. The current thus calculated is used to obtain the effective length for the equivalent rectangular device. We show that this method is much more accurate than previously proposed approaches which neglect the location dependence of the threshold voltage.

Gupta, Puneet; Kahng, Andrew; Kim, Youngmin; Shah, Saumil; Sylvester, Dennis

2006-03-01

426

Design for a New Signal Analyzer through a Circuit Modeling Simulation as a One Body System for SAC's  

SciTech Connect

A circuit simulation analysis and diagnosis methods are used to diagnose instruments in detail when they give apparently abnormal readings. In this paper, a new simulator for analyzing the modeling of important circuits under SACs(severe accident conditions) has been designed. The realization of a one body system by using a one order command system in the LabVIEW and Pspice was used instead of a complex two body system. The program shows the output data from the circuit modeling according to a one order command system. The procedure for the simulator design was divided into two steps, of which the first step was the design of the diagnosis methods, and the second step was a circuit simulator for the signal processing tool and the special signal analysis tool. It has three main functions which are a signal processing tool, an accident management tool, and an additional guide from the initial screen. (authors)

Kil-Mo, Koo; Sang-Baik, Kim; Hee-Dong, Kim [Department of Thermal-Hydraulic Safety Research Team, KAERI, 150 Dukjin-dong, Yuseong, Daejeon, 305-353 (Korea, Republic of); Hae-Yong, Kang [Semiconductor Research Institute, Korea University, Daejeon (Korea, Republic of)

2006-07-01

427

LDRD Final Report - Investigations of the impact of the process integration of deposited magnetic films for magnetic memory technologies on radiation-hardened CMOS devices and circuits - LDRD Project (FY99)  

SciTech Connect

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.

MYERS,DAVID R.; JESSING,JEFFREY R.; SPAHN,OLGA B.; SHANEYFELT,MARTY R.

2000-01-01

428

CAFFEINE: Template-Free Symbolic Model Generation of Analog Circuits via Canonical Form Functions and Genetic Programming  

E-print Network

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.

Mcconaghy, Trent; Gielen, Georges

2011-01-01

429

A phenomenological constitutive model for magnetic shape memory alloys  

E-print Network

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 model development is conducted...

Kiefer, Bjoern

2007-04-25

430

Modeling the macromolecular background in Nuclear Magnetic Resonance spectroscopic signals  

E-print Network

1 Modeling the macromolecular background in Nuclear Magnetic Resonance spectroscopic signals D- noising, nonparametric modeling, macromolecular back- ground. I. INTRODUCTION Nuclear Magnetic Resonance Engineering (ESAT-SCD), Leuven, Belgium Abstract--Metabolite quantitation of Nuclear Magnetic Resonance

431

Nuclear-magnetic-resonance characterization of doped SiO2 films used in integrated circuits  

NASA Astrophysics Data System (ADS)

Phosphorus-doped silicon dioxide dielectric films, prepared by plasma-enhanced chemical-vapor deposition at low temperature (400 °C), play a critical role in the reliability of very large scale integration devices. The phosphorus in the phosphosilicate glass (PSG) neutralizes the effect of mobile ion species and improves the glass flow, resulting in better gap filling and improved planarization. To extract the maximum contribution from this and other doped films (boron and germanium doped) in advanced sub-0.5 ?m complimentary metal-oxide-semiconductor technologies, it is necessary to understand dopant incorporation and the effects of variation in the exposure to water, dopant concentration, and high-temperature annealing. An analysis of PSG by 1H, 29Si, and 31P solid-state nuclear magnetic resonance establishes the chemistry of the phosphorus dopant incorporation and the effect of moisture on the glass structures. Exposure to water results in a depolymerization of the PSG structures and a concurrent decrease in the crosslink density of the glass network. Similar concentrations of silanols are observed in both doped and undoped samples of SiO2. An increase in silanol concentration is found in P-doped glass after exposure to moisture in air. The level of exposure to water will determine the extent of structural changes in the dielectric film. Variations in this exposure can be expected to produce variability in the glass flow and other properties of the dielectric.

Schilling, Frederic C.; Steiner, Kurt G.; Obeng, Yaw S.

1995-07-01

432

Nuclear-magnetic-resonance characterization of doped SiO2 films used in integrated circuits  

NASA Astrophysics Data System (ADS)

Phosphorus-doped silicon dioxide dielectric films, prepared by plasma-enhanced chemical-vapor deposition at low temperature (400 °C), play a critical role in the reliability of very large scale integration devices. The phosphorus in the phosphosilicate glass (PSG) neutralizes the effect of mobile ion species and improves the glass flow, resulting in better gap filling and improved planarization. To extract the maximum contribution from this and other doped films (boron and germanium doped) in advanced sub-0.5 ?m complimentary metal-oxide-semiconductor technologies, it is necessary to understand dopant incorporation and the effects of variation in the exposure to water, dopant concentration, and high-temperature annealing. An analysis of PSG by 1H, 29Si, and 31P solid-state nuclear magnetic resonance establishes the chemistry of the phosphorus dopant incorporation and the effect of moisture on the glass structures. Exposure to water results in a depolymerization of the PSG structures and a concurrent decrease in the crosslink density of the glass network. Similar concentrations of silanols are observed in both doped and undoped samples of SiO2. An increase in silanol concentration is found in P-doped glass after exposure to moisture in air. The level of exposure to water will determine the extent of structural changes in the dielectric film. Variations in this exposure can be expected to produce variability in the glass flow and other properties of the dielectric.

Schilling, Frederic C.; Steiner, Kurt G.; Obeng, Yaw S.

1995-09-01

433

Injection compression modeling of non-linear positive temperature coefficient circuit protection devices  

E-print Network

Polymeric self-resettable circuit protection devices have been manufactured for many years with an extrusion based process. These devices add negligible resistance to a circuit at normal power operating conditions but ...

Hardy, Joseph T., 1978-

2005-01-01

434

CAFFEINE: Template-Free Symbolic Model Generation of Analog Circuits via Canonical Form Functions and Genetic Programming  

E-print Network

CAFFEINE: Template-Free Symbolic Model Generation of Analog Circuits via Canonical Form Functions been used to train neural networks as in [2,3,4]. However, such models provide no insight. The aim of symbolic modeling is to use simulation data to generate interpretable mathematical expressions that relate

Paris-Sud XI, Université de

435

Nonorthogonal PEEC formulation for time- and frequency-domain EM and circuit modeling  

Microsoft Academic Search

Electromagnetic solvers based on the partial element equivalent circuit (PEEC) approach have proven to be well suited for the solution of combined circuit and EM problems. The inclusion of all types of Spice circuit elements is possible. Due to this, the approach has been used in many different tools. Most of these solvers have been based on a rectangular or

Albert E. Ruehli; Giulio Antonini; Joris Esch; Jonas Ekman; Anita Mayo; Antonio Orlandi

2003-01-01

436

Computing with a canonical neural circuits model with pool normalization and modulating feedback.  

PubMed

Evidence suggests that the brain uses an operational set of canonical computations like normalization, input filtering, and response gain enhancement via reentrant feedback. Here, we propose a three-stage columnar architecture of cascaded model neurons to describe a core circuit combining signal pathways of feedforward and feedback processing and the inhibitory pooling of neurons to normalize the activity. We present an analytical investigation of such a circuit by first reducing its detail through the lumping of initial feedforward response filtering and reentrant modulating signal amplification. The resulting excitatory-inhibitory pair of neurons is analyzed in a 2D phase-space. The inhibitory pool activation is treated as a separate mechanism exhibiting different effects. We analyze subtractive as well as divisive (shunting) interaction to implement center-surround mechanisms that include normalization effects in the characteristics of real neurons. Different variants of a core model architecture are derived and analyzed-in particular, individual excitatory neurons (without pool inhibition), the interaction with an inhibitory subtractive or divisive (i.e., shunting) pool, and the dynamics of recurrent self-excitation combined with divisive inhibition. The stability and existence properties of these model instances are characterized, which serve as guidelines to adjust these properties through proper model parameterization. The significance of the derived results is demonstrated by theoretical predictions of response behaviors in the case of multiple interacting hypercolumns in a single and in multiple feature dimensions. In numerical simulations, we confirm these predictions and provide some explanations for different neural computational properties. Among those, we consider orientation contrast-dependent response behavior, different forms of attentional modulation, contrast element grouping, and the dynamic adaptation of the silent surround in extraclassical receptive field configurations, using only slight variations of the same core reference model. PMID:25248083

Brosch, Tobias; Neumann, Heiko

2014-12-01

437

Detection of the Short-Circuit Faults in the Stator Winding of Induction Motors based on Harmonics of the Neighboring Magnetic Field  

NASA Astrophysics Data System (ADS)

Based on the time domain finite element analysis of the electromagnetic field, this paper studies the signature of the short-circuit faults inside the stator winding in the magnetic field outside induction motors. The detection of the such a fault is based on the evaluation of the output voltage of coil sensors placed in the motors neighbouring and the comparison of amplitudes of harmonics of this voltage for the healthy and faulty operation states.

Fireteanu, V.

2013-06-01

438

Magnetic Dipole Field 3D Model  

NSDL National Science Digital Library

The Magnetic Dipole Field 3D Model displays the field lines and field vectors of a dipole located at the origin and oriented along the z-axis. Users can compute the field line passing through a point by dragging the a marker within the 3D view. Users can also visualize the field vectors in a plane passing though the center of the dipole. The Magnetic Dipole Field 3D Model was developed using the Easy Java Simulations (Ejs) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_em_MagneticDipole3D.jar file will run the program if Java is installed. EJS is a part of the Open Source Physics Project and is designed to make it easier to access, modify, and generate computer models.

Christian, Wolfgang

2012-08-11

439

Numerical Based Linear Model for Dipole Magnets  

SciTech Connect

In this paper, we discuss an algorithm for constructing a numerical linear optics model for dipole magnets from a 3D field map. The difference between the numerical model and K. Brown's analytic approach is investigated and clarified. It was found that the optics distortion due to the dipoles' fringe focusing must be properly taken into account to accurately determine the chromaticities. In NSLS-II, there are normal dipoles with 35-mm gap and dipoles for infrared sources with 90-mm gap. This linear model of the dipole magnets is applied to the NSLS-II lattice design to match optics parameters between the DBA cells having dipoles with different gaps.

Li,Y.; Krinsky, S.; Rehak, M.

2009-05-04

440

Circuits programmables 1 Circuits VLSI  

E-print Network

Circuits programmables 1 Circuits VLSI programmables Alain GUYOT TIMA TIMA Techniques de l,version1-12Sep2006 #12;Circuits programmables 2 Du Micro au Micron Microprocesseur, micro-ordinateur monoboitier Circuits programmables dynamiquement Circuits programmables statiquement Tableaux, mer de portes

Paris-Sud XI, Université de

441

Behavioural model of Spin Torque Transfer Magnetic Tunnel Junction, Using Verilog-A  

NASA Astrophysics Data System (ADS)

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.

Garg, Rishubh; Kumar, Deepak; Jindal, Navneet; Negi, Nandita; Ahuja, Chetna

2012-11-01

442

Integration of MHD load models with circuit representations the Z generator.  

SciTech Connect

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.

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

443

High-temperature superconducting quantum interference device with cooled LC resonant circuit for measuring alternating magnetic fields with improved signal-to-noise ratio  

SciTech Connect

Certain applications of superconducting quantum interference devices (SQUIDs) require a magnetic field measurement only in a very narrow frequency range. In order to selectively improve the alternating-current (ac) magnetic field sensitivity of a high-temperature superconductor SQUID for a distinct frequency, a single-coil LC resonant circuit has been used. Within the liquid nitrogen bath, the coil surrounds the SQUID and couples to it inductively. Copper coils with different numbers of windings were used to cover the frequency range from <1 to nearly 100 kHz. A superconducting coil made of YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} tape conductor was also tested. With the LC circuit, the signal-to-noise ratio of measurements could be improved typically by one order of magnitude or more in a narrow frequency band around the resonance frequency exceeding a few kilohertz. The best attained equivalent magnetic field resolution was 2.5 fT/{radical}Hz at 88 kHz. The experimental findings are in good agreement with mathematical analysis of the circuit with copper coil.

Qiu Longqing; Zhang Yi; Krause, Hans-Joachim; Braginski, Alex I.; Usoskin, Alexander [Institute of Bio- and Nanosystem (IBN-2), Research Center Juelich, D-52425 Juelich (Germany) and Pohl Institute of Solid State Physics, Tongji University, Shanghai 200092 (China); Institute of Bio- and Nanosystem (IBN-2), Research Center Juelich, D-52425 Juelich (Germany); European High Temperature Superconductors GmbH and Co. KG, D-63450 Hanau (Germany)

2007-05-15

444

High-temperature superconducting quantum interference device with cooled LC resonant circuit for measuring alternating magnetic fields with improved signal-to-noise ratio.  

PubMed

Certain applications of superconducting quantum interference devices (SQUIDs) require a magnetic field measurement only in a very narrow frequency range. In order to selectively improve the alternating-current (ac) magnetic field sensitivity of a high-temperature superconductor SQUID for a distinct frequency, a single-coil LC resonant circuit has been used. Within the liquid nitrogen bath, the coil surrounds the SQUID and couples to it inductively. Copper coils with different numbers of windings were used to cover the frequency range from <1 to nearly 100 kHz. A superconducting coil made of YBa(2)Cu(3)O(7-delta) tape conductor was also tested. With the LC circuit, the signal-to-noise ratio of measurements could be improved typically by one order of magnitude or more in a narrow frequency band around the resonance frequency exceeding a few kilohertz. The best attained equivalent magnetic field resolution was 2.5 fT/radicalHz at 88 kHz. The experimental findings are in good agreement with mathematical analysis of the circuit with copper coil. PMID:17552846

Qiu, Longqing; Zhang, Yi; Krause, Hans-Joachim; Braginski, Alex I; Usoskin, Alexander

2007-05-01

445

A novel ECMO circuit using a SYNERGY circulite pump in a swine model.  

PubMed

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

Biscotti, Mauer; Singh, Gopal; Downey, Peter; Bacchetta, Matthew

2014-01-01

446

Frequency method for determining the parameters of the electromagnetic brakes and slip-type couplings with solid magnetic circuits  

NASA Technical Reports Server (NTRS)

The equivalent representation of brakes and coupling by lumped circuits is investigated. Analytical equations are derived for relating the indices of the transients to the parameters of the equivalent circuits for arbitrary rotor speed. A computer algorithm is given for the calculations.

Guseynov, F. G.; Abbasova, E. M.

1977-01-01

447

Magnetic Refrigeration Development  

NASA Technical Reports Server (NTRS)

Magnetic refrigeration is being developed to determine whether it may be used as an alternative to the Joule-Thomson circuit of a closed cycle refrigerator for providing 4 K refrigeration. An engineering model 4-15 K magnetic refrigerator has been designed and is being fabricated. This article describes the overall design of the magnetic refrigerator.

Deardoff, D. D.; Johnson, D. L.

1984-01-01

448

Modeling solar force-free magnetic fields  

NASA Astrophysics Data System (ADS)

A class of nonlinear force-free magnetic fields is presented, described in terms of the solutions to a second-order, nonlinear ordinary differential equation. These magnetic fields are three-dimensional, filling the infinite half-space above a plane where the lines of force are anchored. They model the magnetic fields of the sun over active regions with a striking geometric realism. The total energy and the free energy associated with the electric current are finite and can be calculated directly from the magnetic field at the plane boundary using the virial theorem. In the study of solar magnetic fields with data from vector magnetographs, there is a long-standing interest in devising algorithms to extrapolate for the force-free magnetic field in a given domain from prescribed field values at the boundary. The closed-form magnetic fields of this paper open up an opportunity for testing the reliability and accuracy of algorithms that claim the capability of performing this extrapolation. The extrapolation procedure as an ill-posed mathematical problem is discussed.

Low, B. C.; Lou, Y. Q.

1990-03-01

449

STDP Installs in Winner-Take-All Circuits an Online Approximation to Hidden Markov Model Learning  

PubMed Central

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

Kappel, David; Nessler, Bernhard; Maass, Wolfgang

2014-01-01

450

An electrical circuit model of the alpha-beta merging seen in dielectric relaxation of ultraviscous liquids  

Microsoft Academic Search

We present a new model for dielectric data in the alpha-beta merging region. The model is constructed using electrical circuit analogies. It leads to an interpretation of the merging region as one where the total relaxation upon cooling separates in two relaxation processes, consistent with a view where the relaxing entities involved are the same for the two processes. We

Neslihan Saglanmak; Albena I. Nielsen; Niels Boye Olsen; Jeppe C. Dyre; Kristine Niss

2010-01-01

451

Parameter estimation for a model of gap gene circuits with time-variable external inputs in Drosophila  

Microsoft Academic Search

We study a model for spatio-temporal pattern formation of gap gene products in the early development of Drosophila. In contrast to previous studies of gap gene circuits, our model incorporates a number of proteins as time-variable external inputs, including a protein Huckebein which is necessary for setting up the correct posterior domain boundary and its shift in time for the

M. Ashyraliyev

2009-01-01

452

Derivation of a continuum model and its electric equivalent-circuit representation for ionic polymer–metal composite (IPMC) electromechanics  

Microsoft Academic Search

Biomedical engineering applications of ionic polymer–metal composites such as motion devices for endoscopy, pumps, valves, catheter navigation mechanisms and spinal pressure sensors make it important to properly model IPMCs for engineering design. In particular, IPMC continuum models and their electric equivalent circuit representation are critical to a more efficient design of IPMC devices. In this paper, we propose a new

P. J. Costa Branco; J. A. Dente

2006-01-01

453

MODELING AND SIMULATION OF THE PRIMARY CIRCUIT OF THE PAKS NUCLEAR POWER PLANT FOR CONTROL AND DIAGNOSIS  

Microsoft Academic Search

Two related but different dynamic simulators of the primary circuit of the Paks Nuclear Power Plant in Hungary are described in this paper that have been built from a simple dynamic model based on first engineering principles. For dynamic analysis and controller design purposes a simple continuous time discrete-continuous hybrid state-space model has been developed that is implemented in the

Erzsébet Németh; Csaba Fazekas; Gábor Szederkényi; Katalin M. Hangos

454

Modelling the Connection of Alternative Energy Sources to the Three-phase Utility Grid for Circuit Simulation  

Microsoft Academic Search

The paper proposes a model for the practical circuit needed to interface a VSI to the three-phase utility grid for connection of alternative energy sources. The model is deduced by considering both the inverter and grid voltages as being constituted by a superposition of modal (differential and omopolar) components. This approach allows identifying a transfer function of the interface, whose

Federico Scapino

2006-01-01

455

A description of a prototype miniature extracorporeal membrane oxygenation circuit using current technologies in a sheep model.  

PubMed

In the United States, standardization of neonatal extracorporeal membrane oxygenation (ECMO) circuit was achieved during the 1980s. Since that time, the consoles and components of the ECMO circuit have remained fundamentally unchanged (bladder, rollerpump, silicone membrane oxygenator). Extracorporeal technology, however, has witnessed many significant advancements in components during the past two decades. These new technologies have characteristics that may improve outcomes when applied in the ECMO arena. Understanding how these technologies perform in long-term applications is necessary. Therefore, the purpose of this project is to evaluate the performance of a miniature ECMO circuit consisting of current generation technologies in an animal model. An ECMO circuit (prime volume 145 mL) was designed that included a hollow fiber oxygenator and a remote mounted centrifugal pump. All circuit tubing and components were surface coated. Three sheep (approx 13 kg) were placed on ECMO using standard neck cannulation techniques and maintained according to clinical protocols. Technical implementation, oxygenator function, and hematological parameters were accessed. Duration of ECMO was 20, 48, and 58 hours. There was no evidence of oxygenator failure, as measured by pressure drop and oxygen transfer, in any of the procedures. No plasma leak was observed in any oxygenators. Platelet count trended downward after 24 hours. Visual inspection after ECMO showed very little evidence of gross thrombosis. This ECMO circuit design departs dramatically from the typical North American systems. The use of this console and components facilitated a 70% reduction in priming volume over a traditional ECMO circuit. Further investigations should be conducted to determine if circuit miniaturization can reduce the morbidity associated with blood product consumption and the bloods contact with the artificial surfaces of the ECMO circuitry. PMID:16350388

Terry, Bryan; Gunst, Gordy; Melchior, Richard; Wolfe, David; Feocco, Nancy; Graham, Susan; Searles, Bruce; Darling, Edward

2005-09-01

456

Dynamic instabilities in magnetically levitated models  

NASA Astrophysics Data System (ADS)

Experiments are reported demonstrating divergence and flutter instabilities in an electrodynamic maglev vehicle. The conducting guideway consists of L-shaped aluminum segments attached to a rotating wheel and qualitatively simulates the Japanese full scale guideway at Miyazaki. The model vehicle employed rare earth permanent magnets. Quantitative tests for a coupled yaw-lateral vibration show both divergence and flutter. The divergence leads to two stable equilibrium yaw positions, while the flutter instability leads to limit cycle oscillations coupling yaw and lateral motions in the neighborhood of the drag peak. A theoretical model based on actual magnetic force measurements is shown to predict this dynamic behavior as functions of vehicle speed and geometry.

Chu, Donald; Moon, Francis C.

1983-03-01

457

Application of circuit simulation method for differential modeling of TIM-2 iron uptake and metabolism in mouse kidney cells  

PubMed Central

Circuit simulation is a powerful methodology to generate differential mathematical models. Due to its highly accurate modeling capability, circuit simulation can be used to investigate interactions between the parts and processes of a cellular system. Circuit simulation has become a core technology for the field of electrical engineering, but its application in biology has not yet been fully realized. As a case study for evaluating the more advanced features of a circuit simulation tool called Advanced Design System (ADS), we collected and modeled laboratory data for iron metabolism in mouse kidney cells for a H ferritin (HFt) receptor, T cell immunoglobulin and mucin domain-2 (TIM-2). The internal controlling parameters of TIM-2 associated iron metabolism were extracted and the ratios of iron movement among cellular compartments were quantified by ADS. The differential model processed by circuit simulation demonstrated a capability to identify variables and predict outcomes that could not be readily measured by in vitro experiments. For example, an initial rate of uptake of iron-loaded HFt (Fe-HFt) was 2.17 pmol per million cells. TIM-2 binding probability with Fe-HFt was 16.6%. An average of 8.5 min was required for the complex of TIM-2 and Fe-HFt to form an endosome. The endosome containing HFt lasted roughly 2 h. At the end of endocytosis, about 28% HFt remained intact and the rest was degraded. Iron released from degraded HFt was in the labile iron pool (LIP) and stimulated the generation of endogenous HFt for new storage. Both experimental data and the model showed that TIM-2 was not involved in the process of iron export. The extracted internal controlling parameters successfully captured the complexity of TIM-2 pathway and the use of circuit simulation-based modeling across a wider range of cellular systems is the next step for validating the significance and utility of this method. PMID:23761763

Xie, Zhijian; Harrison, Scott H.; Torti, Suzy V.; Torti, Frank M.; Han, Jian

2013-01-01

458

Magnetic field gradients from the ST-5 constellation: Improving magnetic and thermal models of the lithosphere  

E-print Network

. A magnetic cleanliness program, and preflight calibration at the GSFC magnetic test facility, ensuredMagnetic field gradients from the ST-5 constellation: Improving magnetic and thermal models the development of a new technique (magnetic gradiometry) for satellite-based remote sensing of the lithosphere

Busby, Cathy

459

Magnetic models on various topologies  

NASA Astrophysics Data System (ADS)

A brief review is given on the study of the thermodynamic properties of spin models defined on different topologies like small-world, scale-free networks, random graphs and regular and random lattices. Ising, Potts and Blume-Capel models are considered. They are defined on complex lattices comprising Appolonian, Barabási-Albert, Voronoi-Delauny and small-world networks. The main emphasis is given on the corresponding phase transitions, transition temperatures, critical exponents and universality, compared to those obtained by the same models on regular Bravais lattices.

Lima, F. W. S.; Plascak, J. A.

2014-03-01

460

Feedback and sensitivity in an electrical circuit: An analog for climate models  

SciTech Connect

Earth's climate sensitivity is often interpreted in terms of feedbacks that can alter the sensitivity from that of a no-feedback Stefan-Boltzmann radiator, with the feedback concept and algebra introduced by analogy to the use of this concept in the electronics literature. This analogy is quite valuable in interpreting the sensitivity of the climate system, but usage of this algebra and terminology in the climate literature is often inconsistent, with resultant potential for confusion and loss of physical insight. Here a simple and readily understood electrical resistance circuit is examined in terms of feedback theory to introduce and define the terminology that is used to quantify feedbacks. This formalism is applied to the feedbacks in an energy-balance model of Earth's climate and used to interpret the magnitude of feedback in the climate system that corresponds to present estimates of Earth's climate sensitivity.

Schwartz, S.E.

2010-07-27

461

Equivalent circuit modeling and vibrometry measurements of the Nigerian-origin Udu Utar drum.  

PubMed

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

Anderson, Brian E; Hilton, C Beau; Giorgini, Frank

2013-03-01

462

Bandwidth-enhanced polarization-insensitive microwave metamaterial absorber and its equivalent circuit model  

NASA Astrophysics Data System (ADS)

In this paper, a bandwidth-enhanced polarization-insensitive ultra-thin metamaterial absorber has been presented. A simple equivalent circuit model has been proposed describing the absorption phenomenon to estimate the frequency of absorption of the proposed microwave absorber. The basic structure consists of concentric rings embedded one inside another to enhance bandwidth by incorporating the scalability property of the metamaterials. Simulation results show that the structure has enhanced bandwidth response with full width at half maxima (FWHM) of 1.15 GHz (9.40-10.55 GHz) with two absorption peaks at 9.66 and 10.26 GHz (96% and 92.5% absorptivity, respectively). The structure is symmetric in design giving rise to polarization-insensitivity and can achieve high absorption for oblique incidence up to 40°. The proposed absorber has been fabricated and measured in anechoic chamber, showing that experimental results agree well with the simulated responses.

Ghosh, Saptarshi; Bhattacharyya, Somak; Kaiprath, Yadunath; Vaibhav Srivastava, Kumar

2014-03-01

463

Design and Modeling of a 3-D Magnetic Actuator for Magnetic Microbead Manipulation  

PubMed Central

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

Zhang, Zhipeng; Menq, Chia-Hsiang

2013-01-01

464

Quantum Adiabatic Circuits  

E-print Network

We introduce a class of quantum adiabatic algorithms that we claim may be treated as the equivalents of the unitary gates of the quantum gate model. We argue that these gates form a universal set and may therefore be used as building blocks in the construction of arbitrary `adiabatic circuits', analogously to the manner in which the gates are used in the circuit model. One implication of the above constructions is that arbitrary classical boolean circuits as well as gate model circuits may be directly translated to adiabatic algorithms with no additional resources or complexities.

Itay Hen

2014-01-21

465

Verification of DC magnetic model predicitions at spacecraft level  

Microsoft Academic Search

Space missions regularly employ magnetic field instruments, which rely on magnetic cleanliness of the spacecraft [1]. We developed a software tool to compile a DC magnetic model and to predict far-field magnetic fields generated by the spacecraft [2]: units and components of the spacecraft are represented by remanent and induced magnetic dipole moments which can be obtained from measurements, derived

A. Junge; F. Marliani

2012-01-01

466

Anti-electromagnetic interference analysis of equivalent circuit of ion channel based on the Hodgkin-Huxley model  

NASA Astrophysics Data System (ADS)

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.

Chu, J.; Chang, X. L.; Zhao, M.; Man, M. H.; Yuan, L.; Wei, M.

2013-03-01

467

Digital reconstruction of the cell body in dense neural circuits using a spherical-coordinated variational model.  

PubMed

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

Quan, Tingwei; Li, Jing; Zhou, Hang; Li, Shiwei; Zheng, Ting; Yang, Zhongqing; Luo, Qingming; Gong, Hui; Zeng, Shaoqun

2014-01-01

468

Modeling bubbles and droplets in magnetic fluids.  

PubMed

We develop, test and apply a volume of fluid (VOF) type code for the direct numerical simulation of two-fluid configurations of magnetic fluids with dynamic interfaces. Equilibrium magnetization and linear magnetic material are assumed and uniform imposed magnetic fields are considered, although extensions to nonlinear materials and to fields with spatio-temporal variability are possible. Models are computed for configurations of bubbles of non-magnetic fluid rising in ferrofluid and droplets of ferrofluid falling through non-magnetic fluid. Bubbles and droplets exhibit similar changes of shape in the presence of vertical fields, due to a combination of elongation along the field lines and the fluid dynamics of ordinary rising or falling at small Bond number. Bubbles become more prolate than droplets under the same parameters and are accordingly found to break up more readily than droplets in stronger fields. Indirect effects are observed, such as the change in rise time and the consequent changes in the flow due to increased Reynolds number. PMID:21694272

Korlie, Mark S; Mukherjee, Arup; Nita, Bogdan G; Stevens, John G; Trubatch, A David; Yecko, Philip

2008-05-21

469

A Neural Circuit Model of Flexible Sensori-motor Mapping: Learning and Forgetting on Multiple Timescales  

PubMed Central

Summary Volitional behavior relies on the brain’s ability to remap sensory flow to motor programs whenever demanded by a changed behavioral context. To investigate the circuit basis of such flexible behavior, we have developed a biophysically-based decision-making network model of spiking neurons for arbitrary sensorimotor mapping. The model quantitatively reproduces behavioral and prefrontal single-cell data from an experiment in which monkeys learn visuo-motor associations that are reversed unpredictably from time to time. We show that when synaptic modifications occur on multiple timescales, the model behavior becomes flexible only when needed: slow components of learning usually dominate the decision process. However, if behavioral contexts change frequently enough, fast components of plasticity take over, and the behavior exhibits a quick forget-and-learn pattern. This model prediction is confirmed by monkey data. Therefore, our work reveals a scenario for conditional associative learning that is distinct from instant switching between sets of well established sensorimotor associations. PMID:17442251

Fusi, Stefano; Asaad, Wael F.; Miller, Earl K.; Wang, Xiao-Jing

2007-01-01

470

Model-based predictions of solid state intermetallic compound layer growth in hybrid microelectronic circuits  

SciTech Connect

A mathematical model was developed to quantitatively describe the intermetallic compound (IMC) layer growth that takes place between a Sn-based solder and a noble metal thick film conductor material used in hybrid microcircuit (HMC) assemblies. The model combined the reaction kinetics of the solder/substrate interaction, as determined from ancillary isothermal aging experiments, with a 2-D finite element mesh that took account of the porous morphology of the thick film coating. The effect of the porous morphology on the IMC layer growth when compared to the traditional 1-D computations was significant. The previous 1-D calculations under-predicted the nominal IMC layer thickness relative to the 2-D case. The 2-D model showed greater substrate consumption by IMC growth and lesser solder consumption that was determined with the 1-D computation. The new 2-D model allows the design engineer to better predict circuit aging and hence, the reliability of HMC hardware that is placed in the field.

Vianco, P.T.; Erickson, K.L.; Hopkins, P.L.

1997-12-31

471

Model simulations of strong atmospheric conductivity disturbances and induced responses of the Global Electric Circuit  

NASA Astrophysics Data System (ADS)

Electrical conductivity in the troposphere and stratosphere is an important quantity that determines the distribution of currents in the GEC (Global Electric Circuit), as well as the potential difference between the Earth and the ionosphere. Recently, progress in modeling atmospheric conductivity has been achieved by integrating the conductivity calculation into an AC-GCM (atmospheric chemistry general circulation model), which provides all relevant data. In this study, WACCM (Whole Atmosphere Community Climate Model) is used for conductivity calculations and an analysis of the effects of strong disturbances on the GEC. This includes volcanic eruptions of Pinatubo in 1991 and the super volcano Toba, polar stratospheric clouds, radioactive releases, and the recent strong galactic cosmic ray maximum. In general, there is a decrease in conductivity from enhanced aerosol number densities, resulting from volcanic eruptions or polar stratospheric clouds. Conductivity is increased by additional ionization sources such as radioactive releases, or galactic cosmic ray increases such as during the last solar minimum. The effects of such events on conductivity, column and total resistance, and estimate effects on current distribution and the earth-ionosphere potential difference will be quantified. Percentage change in conductivity at 20 km altitude two months after the Toba volcanic eruption (WACCM model simulation). The enhanced aerosol concentrations lead to a "conductivity hole" between 30°S and 45° N.

Baumgaertner, A. J.; Lehto, E.; Neely, R. R.; English, J. M.; Zhu, Y.; Lucas, G.; Thayer, J. P.

2013-12-01

472

Coupled wave model for large magnet coils  

NASA Technical Reports Server (NTRS)

A wave coupled model based on field theory is evolved for analysis of fast electromagnetic transients on superconducting coils. It is expected to play a useful role in the design of protection methods against damage due to high voltages or any adverse effects that might arise from unintentional transients. The significant parameters of the coil are identified to be the turn to turn wave coupling coefficients and the travel time of an electromagnetic disturbance around a single turn. Unlike circuit theoretic inductor, the coil response evolves in discrete steps having durations equal to this travel time. It is during such intervals that high voltages are likely to occur. The model also bridges the gap between the low and high ends of the frequency spectrum.

Gabriel, G. J.

1980-01-01

473

Model of a rotating magnetic cloud  

NASA Technical Reports Server (NTRS)

The possibility that magnetic clouds rotate while they propagate antisunward was investigated. Magnetic clouds are modeled as magnetic flux ropes which rotate rigidly about the axis of symmetry. An ideal magnetohydrodynamic model, in which the evolution of the magnetic structure is related to the time evolution of the angular frequency, is developed. A class of 'separable' magnetic fields is employed to reduce the problem to a nonlinear ordinary differential equation for the evolution function, and it is solved numerically. The corresponding effective potential gives rise to two modes of evolution--expansion and oscillation--depending on the energy and on the value of a dimensionless parameter, k. Parameter k depends on the gas pressure, the ratio of the magnetic field components, and the frequency of rotation. There is a critical value of k, k(sub c), above which the oscillatory regime disappears and the flux rope invariably expands, regardless of the energy. Below k(sub c) the energy determines whether the configuration is confined or unbounded. Rotation always helps expansion by lowering the potential barrier. A data example was studied and features which are interpreted as signatures of rotation are presented. The angular speed is comparable to the Alfven speed, and the core of the rotating cloud completes on average one full revolution every three days at 1 AU. The parameter k is calculated from observations, and it is found to be close to, but below, critical. Only three out of the nine clouds examined showed signatures of rotation. Theoretical analysis suggests that close to the Sun rotation effects may play a more important role in the evolution of magnetic clouds than 1 AU.

Farrugia, C. J.; Osherovich, V. A.; Burlaga, L. F.

1992-01-01

474

Temperature Control of Fimbriation Circuit Switch in Uropathogenic Escherichia coli: Quantitative Analysis via Automated Model Abstraction  

PubMed Central

Uropathogenic Escherichia coli (UPEC) represent the predominant cause of urinary tract infections (UTIs). A key UPEC molecular virulence mechanism is type 1 fimbriae, whose expression is controlled by the orientation of an invertible chromosomal DNA element—the fim switch. Temperature has been shown to act as a major regulator of fim switching behavior and is overall an important indicator as well as functional feature of many urologic diseases, including UPEC host-pathogen interaction dynamics. Given this panoptic physiological role of temperature during UTI progression and notable empirical challenges to its direct in vivo studies, in silico modeling of corresponding biochemical and biophysical mechanisms essential to UPEC pathogenicity may significantly aid our understanding of the underlying disease processes. However, rigorous computational analysis of biological systems, such as fim switch temperature control circuit, has hereto presented a notoriously demanding problem due to both the substantial complexity of the gene regulatory networks involved as well as their often characteristically discrete and stochastic dynamics. To address these issues, we have developed an approach that enables automated multiscale abstraction of biological system descriptions based on reaction kinetics. Implemented as a computational tool, this method has allowed us to efficiently analyze the modular organization and behavior of the E. coli fimbriation switch circuit at different temperature settings, thus facilitating new insights into this mode of UPEC molecular virulence regulation. In particular, our results suggest that, with respect to its role in shutting down fimbriae expression, the primary function of FimB recombinase may be to effect a controlled down-regulation (rather than increase) of the ON-to-OFF fim switching rate via temperature-dependent suppression of competing dynamics mediated by recombinase FimE. Our computational analysis further implies that this down-regulation mechanism could be particularly significant inside the host environment, thus potentially contributing further understanding toward the development of novel therapeutic approaches to UPEC-caused UTIs. PMID:20361050

Kuwahara, Hiroyuki; Myers, Chris J.; Samoilov, Michael S.

2010-01-01

475

Fear signaling in the prelimbic-amygdala circuit: a computational modeling and recording study  

PubMed Central

The acquisition and expression of conditioned fear depends on prefrontal-amygdala circuits. Auditory fear conditioning increases the tone responses of lateral amygdala neurons, but the increase is transient, lasting only a few hundred milliseconds after tone onset. It was recently reported that that the prelimbic (PL) prefrontal cortex transforms transient lateral amygdala input into a sustained PL output, which could drive fear responses via projections to the lateral division of basal amygdala (BL). To explore the possible mechanisms involved in this transformation, we developed a large-scale biophysical model of the BL-PL network, consisting of 850 conductance-based Hodgkin-Huxley-type cells, calcium-based learning, and neuromodulator effects. The model predicts that sustained firing in PL can be derived from BL-induced release of dopamine and norepinephrine that is maintained by PL-BL interconnections. These predictions were confirmed with physiological recordings from PL neurons during fear conditioning with the selective ?-blocker propranolol and by inactivation of BL with muscimol. Our model suggests that PL has a higher bandwidth than BL, due to PL's decreased internal inhibition and lower spiking thresholds. It also suggests that variations in specific microcircuits in the PL-BL interconnection can have a significant impact on the expression of fear, possibly explaining individual variability in fear responses. The human homolog of PL could thus be an effective target for anxiety disorders. PMID:23699055

Pendyam, Sandeep; Bravo-Rivera, Christian; Burgos-Robles, Anthony; Sotres-Bayon, Francisco; Quirk, Gregory J.

2013-01-01

476

Fear signaling in the prelimbic-amygdala circuit: a computational modeling and recording study.  

PubMed

The acquisition and expression of conditioned fear depends on prefrontal-amygdala circuits. Auditory fear conditioning increases the tone responses of lateral amygdala neurons, but the increase is transient, lasting only a few hundred milliseconds after tone onset. It was recently reported that that the prelimbic (PL) prefrontal cortex transforms transient lateral amygdala input into a sustained PL output, which could drive fear responses via projections to the lateral division of basal amygdala (BL). To explore the possible mechanisms involved in this transformation, we developed a large-scale biophysical model of the BL-PL network, consisting of 850 conductance-based Hodgkin-Huxley-type cells, calcium-based learning, and neuromodulator effects. The model predicts that sustained firing in PL can be derived from BL-induced release of dopamine and norepinephrine that is maintained by PL-BL interconnections. These predictions were confirmed with physiological recordings from PL neurons during fear conditioning with the selective ?-blocker propranolol and by inactivation of BL with muscimol. Our model suggests that PL has a higher bandwidth than BL, due to PL's decreased internal inhibition and lower spiking thresholds. It also suggests that variations in specific microcircuits in the PL-BL interconnection can have a significant impact on the expression of fear, possibly explaining individual variability in fear responses. The human homolog of PL could thus be an effective target for anxiety disorders. PMID:23699055

Pendyam, Sandeep; Bravo-Rivera, Christian; Burgos-Robles, Anthony; Sotres-Bayon, Francisco; Quirk, Gregory J; Nair, Satish S

2013-08-01

477

Anomalous transport in discrete arcs and simulation of double layers in a model auroral circuit  

NASA Technical Reports Server (NTRS)

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.

Smith, Robert A.

1987-01-01

478

Anomalous transport in discrete arcs and simulation of double layers in a model auroral circuit  

NASA Technical Reports Server (NTRS)

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.

Smith, Robert A.

1987-01-01

479

Multiphase Resistivity Model for Magnetic Nanocomposites Developed for High Frequency, High Power Transformation  

NASA Astrophysics Data System (ADS)

New power conversion systems that offer promise to transform electricity grids into unified interactive supply networks require high-resistivity soft-magnetic materials to allow for switching of magnetic materials at frequencies approaching 100 kHz for power transformation in the megawatt range. Amorphous and nanocomposite soft-magnetic materials, which represent the state of the art in terms of high power densities and low losses at high frequencies, have resistivities that depend on the structures and spatial distributions of multiple phases in thin ribbons. We present a multiphase resistivity model applicable to nanocomposite materials by considering an equivalent circuit approach considering paths through an amorphous, crystalline, and growth inhibitor shell phase. We detail: (a) identification of amorphous, crystalline, and shell phases; (b) consideration of the role of the morphology of each phase in an equivalent circuit model for the resistance; (c) a two-band model for the Fe/Co composition dependence of the resistivity in crystalline and amorphous phases; (d) a virtual bound state model for resistivity to explain increased resistivity due to early transition-metal growth inhibitors in the shell surrounding the nanocrystalline phase; and (e) disorder effects on amorphous phase resistivity. Experimental design and results for systems of interest in high-frequency power transformation are discussed in the context of our model including: (a) techniques for measurements of cross-section and density, (b) four-point probe and surface resistivity measurements, and (c) measurements in Fe- and Co-rich systems comparing amorphous and nanocomposite materials.

DeGeorge, V.; Shen, S.; Ohodnicki, P.; Andio, M.; McHenry, M. E.

2014-01-01

480

A dynamo model of Jupiter's magnetic field  

NASA Astrophysics Data System (ADS)

Jupiter's dynamo is modelled using the anelastic convection-driven dynamo equations. The reference state model is taken from French et al. [2012]. Astrophys. J. Suppl. 202, 5, (11pp), which used density functional theory to compute the equation of state and the electrical conductivity in Jupiter's interior. Jupiter's magnetic field is approximately dipolar, but self-consistent dipolar dynamo models are rather rare when the large variation in density and the effective internal heating are taken into account. Jupiter-like dipolar magnetic fields were found here at small Prandtl number, Pr=0.1. Strong differential rotation in the dynamo region tends to destroy a dominant dipolar component, but when the convection is sufficiently supercritical it generates a strong magnetic field, and the differential rotation in the electrically conducting region is suppressed by the Lorentz force. This allows a magnetic field to develop which is dominated by a steady dipolar component. This suggests that the strong zonal winds seen at Jupiter's surface cannot penetrate significantly into the dynamo region, which starts approximately 7000 km below the surface.

Jones, C. A.

2014-10-01

481

Multiscale Modeling of Solar Coronal Magnetic Reconnection  

NASA Technical Reports Server (NTRS)

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