Modifications of the DC Raytheon–Statz model for SiC MESFETs

In the paper the problem of modelling DC characteristics of SiC MESFETs is presented. Some modifications of the popular Raytheon–Statz model built‐in in SPICE are proposed. The original and the modified models are verified experimentally by comparison of the measured and simulated device characteristics. One of the two available today on the market SiC MESFETs–the transistor CRF24010 offered by Cree, Inc. is chosen for investigations. Copyright © 2008 John Wiley & Sons, Ltd.     

Electrical model of the alkaline electrolyser dedicated for SPICE

In this paper, properties of the alkaline electrolyser fed from the voltage source, producing the rectangular pulse train, were investigated. A model of this electrolyser for SPICE in the form of an electrical network was proposed. The structure of this electrical model was described, and the values of parameters of the model were presented. The correctness of this model was verified experimentally in a wide range of frequency. Using the worked out model, several characteristics of the electrolyser were calculated, and the influence of amplitude, frequency, and the duty factor of the supplying voltage on productivity and watt‐hour efficiency of the electrolysis process was discussed. The investigations were performed for 2 different concentration values of the KOH solution.     

A general SPICE compatible circuit model for single‐electron devices and application to bit‐error‐rate calculations

The main purpose of this paper is study of the single‐electron devices (SEDs) behavior, having metal islands, in the time domain. On this basis, some new conceptions, such as division of islands in independent type and dependent type and introduction of multi‐dimensional state space for a SED, have been presented. Then, a new circuit model is introduced for SEDs in general N‐dimensional case. This model is based on the orthodox theory and the solution of the time‐dependent master equation with the capability of installation in the HSPICE software. Hence, one can simulate behavior of the compound circuits including SEDs and other circuit elements by help of this model. Another interesting characteristic of the introduced circuit model is the possibility of using it in calculation of bit error rate in single‐electron logical gates considering both the time and the temperature effects. The behavior of various SEDs in low frequencies is studied, and the results are compared with the results of SIMON, often used as a reference. Furthermore, the time‐dependent results of these devices in high frequencies are calculated and compared with the analytic results for step inputs. These comparisons indicate accuracy and validity of the model. Finally, the model is used for simulating time‐dependent behavior of some single‐electron logic gates, and their total error rate are calculated. Copyright © 2013 John Wiley & Sons, Ltd.     

硅太阳电池工程用数学模型参数的优化设计

根据硅太阳电池工程用数学模型,利用matlab/simulink模块建立了硅太阳电池阵列仿真模型.根据太阳电池组件仿真结果和实际测量结果的比较,分析了硅太阳电池工程用数学模型系数对仿真模型的输出特性精度的影响,并提出了不同太阳辐射强度时硅太阳电池工程用数学模型中系数b的优化设计计算公式.仿真结果表明,利用优化设计计算的参数可提高太阳电池阵列仿真模型的输出特性精度.     

Implementation of the symmetric doped double‐gate MOSFET model in Verilog‐A for circuit simulation

Recently we developed a model for symmetric double‐gate MOSFETs (SDDGM) that, for the first time, considers the doping concentration in the Si film in the complete range from 1×10¹⁴ to 3×10¹⁸ cm⁻³. The model covers a wide range of technological parameters and includes short channel effects. It was validated for different devices using data from simulations, as well as measured in real devices. In this paper, we present the implementation in Verilog‐A code of this model, which allows its introduction in commercial simulators. The Verilog‐A implementation was optimized to achieve reduction in computational time, as well as good accuracy. Results are compared with data from 2D simulations, showing a very good agreement in all transistor operation regions. Copyright © 2009 John Wiley & Sons, Ltd.     

A three‐dimensional Monte Carlo model for the simulation of nanoelectronic devices

We present a three‐dimensional (3D) semi‐classical ensemble Monte Carlo model newly developed to simulate a variety of nanoelectronic devices. The characteristics of the 3D model are compared with the widely used two‐dimensional (2D) models. The advantages of our model, in terms of accuracy in modelling the physics behind the operation of nanodevices, are presented by applying it to T‐branch junctions based on InGaAs/InAlAs heterostructures. Simulation of a T‐branch junction with a Schottky gate terminal is presented, using both 2D and 3D models, demonstrating the necessity of using 3D simulation models to study the physics of complex‐geometry nanostructures. Copyright © 2009 John Wiley & Sons, Ltd.     

Sensitivity of single- and double-gate MOS architectures to residual discrete dopant distribution in the channel

The effect of a single discrete impurity in the channel of Fully-Depleted Single- and Double-Gate MOSFETs is analyzed by means of 3D Monte Carlo simulation. The Double-Gate (DG) architecture appears to be less sensitive to the dopant perturbation than the Single-Gate (SG) counterpart. For an N-channel device the influence of a P-type impurity on the current-voltage characteristics is shown to be strongly dependent on the impurity position in the channel. The maximum current degradation is obtained for an impurity located about 5 nm from the source-end of the channel. The I _on reduction reaches 6% in DG and 10.5% in SG. A small current enhancement (less than 2%) is induced by an N-type impurity. These results are analyzed in terms of velocity profile between source and drain.     

A novel empirical study of the two‐dimensional non‐linear drain‐current behaviour in sub‐micrometre MOS transistors

This paper presents a simple, quasi‐static, non‐linear (saturated mode) NMOS drain‐current model for Volterra‐series analysis. The model is based on a linear transconductance, a linear drain‐source conductance and a purely non‐linear drain‐source current generator. The drain‐current dependency on both drain‐source and gate‐source voltages is included. Model parameters are then extracted from direct numerical differentiation of DC I/V measurements performed on a 160 × 0.25 µm NMOS device. This paper presents the Volterra analysis of this model, including algebraic expressions for intercept points and output spectrum. The model has been verified by comparing measured two‐tone iIP₂ and iIP₃ with the corresponding model predictions over a wide range of bias points. The correspondence between the modelled and measured response is good. Copyright © 2005 John Wiley & Sons, Ltd.     

A generalized CAD model for the full‐wave modelling of microstrip line and its regular and irregular discontinuities

In this paper we present a new theoretical model for the modelling of the microstrip line as well as two types of discontinuities: regular (open end, step, bend and T‐ and cross‐junctions) and irregular (stub and bent‐stub). The two‐dimensional exact dyadic Green function of a grounded dielectric slab has been used with the Galerkin's technique. The subdivision of the discontinuity in a network of juxtaposed unit cells, characterized by their own longitudinal and transversal current distributions, allowed the treatment of a large class of irregular discontinuities in addition to the regular discontinuities. The obtained results have been commented and compared with those of different approaches and with experimental results where a good concordance has been observed. Copyright © 2006 John Wiley & Sons, Ltd.     

大型发电机用半无机硅钢片漆的研究

叙述了半无机硅钢片漆的国内外研究概况和发展趋势,分析了水溶性漆基和油溶性漆基对半无机硅钢片漆性能的影响,探讨了无机填料的种类,粒径和表面处理等因素对其性能的影响和作用。     

轨道电路内屏蔽电缆多回路模型与其参数计算

内屏蔽数字信号电缆是高速铁路轨道电路的传输通路,其多回路仿真模型与参数计算对研究高速铁路轨道电路信号传输有重要意义。首先,文中考虑内屏蔽数字信号电缆的结构特点和信号传输路径,建立其考虑耦合的多回路电路仿真模型。其次,对多回路中涉及的参数,采用有限元方法,给出电缆电容、电感和电阻参数计算的一般方法,包含有限元计算各类参数的边值问题的详细描述、必要的计算公式和步骤。最后,以8芯内屏蔽电缆为例,建立其仿真模型,通过计算结果与测量结果对比,验证计算方法的正确性。文中建立的多回路模型可用于高速铁路轨道电路信号传输研究和故障诊断。     

新型光纤熔接机中激光功率检测电路设计

设计了一种适用于新型光纤熔接机光功率探测对准系统中激光功率检测电路,通过选用高灵敏度的InGaAs光电二极管实现光电转换.采用差分放大电路进行前置的I/V转换和放大滤波,并对其进行了仿真测试和电路调试.结果表明:该检测电路能够有效的去除工频等噪声的干扰,并且具有稳定的输出信号和放大倍数,实现对输入的激光功率信号进行转换并输出匹配至0～3 V电压范围的A/D转换器中,为后续运用微机控制运动平台进行熔接奠定基础.     

A generalized CAD model for the full‐wave modeling of Coplanar striplines discontinuities

In this work, the coplanar stripline (CPS) and its discontinuities: open‐end, short‐end, gaps and resonator have been modeled. New integral equations for the electrical field components are formulated, in the spectral domain, using an exact dyadic Green's function, applied to the CPS structure. The use of this form of Green's function allows the consideration of the effects of the dielectric losses, the surface wave excitation and the space wave radiation on the propagation characteristics of the CPS and its discontinuities. The resulting integral equation has been solved using the two‐dimensional Galerkin's technique. The resolution of the resulting matrix equation gives the scattering parameters of the studied structures. The obtained results are commented and compared with those of other approaches and measurements. Copyright © 2011 John Wiley & Sons, Ltd.     

Pressure wave propagation in arteries. A model with radialdilatation for simulating the behavior of a real artery

The authors solve the equation of pressure wave propagation in an artery with radial dilatation to give an analytic solution of wave propagation in an elastic vessel for more generalized conditions. This will serve as a complementary solution to work that is based on the assumption that the radial dilatation of the arterial wall is small. The authors' solution is important for physiological studies because it simulates the behavior of a real artery. To confirm the authors' analytic solution, experiments were performed in tubes with different elastic constants     

基于EKF算法的蓄电池等效电路模型参数仿真研究

蓄电池在充放电过程中,其内部存在着复杂的电化学反应,导致蓄电池荷电状态（SOC）及各个参数是多维、非线性的关系。因此,本文基于7-HK-182型铅酸蓄电池建立等效电路模型,进行参数辨识。在此基础上,采用扩展卡尔曼滤波（EKF）算法,利用Matlab软件对蓄电池SOC及各个参数进行实时仿真,通过仿真与实验结果对比验证了EKF算法的实时性与准确性。     

基于上位机KingView的牵引供电系统监控平台演示研究

"牵引供电系统"作为中枢环节对机车运行安全非常重要,建立牵引供电监控系统演示仿真平台,可以模拟、演示设备操作和电路特性,上位机采用KingView组态软件,下位机利用C语言采集数据,分析计算负荷运行数据和仿真能量损耗情况,并建立数据和查询报表、遥控事故分析等演示操作系统,对于理论创新并进一步将其实践化具有重要意义。     

A Non-Parabolic Six Moments Model for the Simulation of Sub-100 nm Semiconductor Devices

Macroscopic transport models derived from Boltzmann’s equation by using the method of moments are often used to efficiently evaluate the electrical behavior of semiconductor devices. The most commonly used model is the drift-diffusion model which comprises the first two moments of Boltzmann’s equation. In this model the carrier gas is assumed to be in equilibrium with the lattice, an assumption severely violated in submicron semiconductor devices. Hydrodynamic and energy-transport models have therefore been proposed to overcome this limitation. However, these extended models have never been widely accepted as a viable substitute, because for small devices they often do not deliver the expected improved accuracy. Here we present a non-parabolic six moments model which predicts considerably more accurate currents than the energy-transport model down to gate-lengths as small as 40 nm.     

电力系统暂态稳定预防控制算法综述

较为全面地综述了国内外关于电力系统暂态稳定预防控制的研究状况。首先通过对预防控制数学模型的分析,给出了预防控制算法在数学表达上的控制过程,并将预防控制算法分为三类,对约束转化技术,最优控制理论,灵敏度技术,单机无穷等效,非线性规划,智能优化等技术在预防控制中的应用做了一定的归纳,对不同算法在常用算例的优化结果做了总结比较。在评述各种算法基础上,对一些算法中存在的问题如初值变分、准确性、迭代次数等进行讨论,并指出了改进预防控制算法的研究方向。     

Experiences in modelling the performance of generating plant for frequency response studies on the British transmission grid

Significant changes to the generation mix on the British transmission system have occurred in the past 10 years, and this trend is expected to continue in the future with an increase in renewable generation. This change, in conjunction with market changes, has driven the need to establish suitable generator models for thermal plant used in dynamic response studies. These studies are presently used to quantify the dynamic requirement that secures the transmission system against large instantaneous losses of power. This paper provides an account of the experiences gained in modelling the performance of generators based in Great Britain. Established governor models to represent the behaviour of traditional coal and oil fired plant already exist and comments are made on their performance against system incidents. Models of combined cycle units using traditional open cycle gas turbine models have shown poor correspondence with monitored grid data in simulations. A gas and steam turbine governor model to represent combined cycle plant was developed, and is presented, with results from validation trials against recorded test data. Improvements in simulating grid frequency have been demonstrated using the developed models in a full network simulation of a recent generator loss event.     

A Bayesian hierarchical model for DCE-MRI to evaluate treatment response in a phase II study in advanced squamous cell carcinoma of the head and neck

Object

Pharmacokinetic parameters from dynamic contrast-enhanced MRI (DCE-MRI) were used to assess the perfusion effects due to treatment response using a tyrosine kinase inhibitor. A Bayesian hierarchical model (BHM) is proposed, as an alternative to voxel-wise estimation procedures, to test for a treatment effect while explicitly modeling known sources of variability.

Materials and methods

Nine subjects from a randomized, blinded, placebo-controlled, multicenter, phase II study of lapatinib were examined before and after treatment. Kinetic parameters were estimated, with an extended compartmental model and subject-specific arterial input function, on a voxel-by-voxel basis.

Results

The group treated with lapatinib had a decrease in median K ^trans of 0.17min^??, when averaged across all voxels in the tumor ROIs, compared with no change in the placebo group based on nonlinear regression. A hypothesis test of equality between pre- and posttreatment K ^trans could not be rejected against a one-sided alternative (P = 0.09). Equality between median K ^trans in placebo and lapatinib groups posttreatment could also not be rejected using the BHM (P = 0.32). Across all scans acquired in the study, estimates of K ^trans at one site were greater on average than those at the other site by including a site effect in the BHM. The inter-voxel variability is of similar order (within 15%) when compared to the inter-patient variability.

Conclusion

Though the study contained a small number of subjects and no significant difference was found, the Bayesian hierarchical model provided estimates of variability from known sources in the study and confidence intervals for all estimated parameters. We believe the BHM provides a straightforward and thorough interrogation of the imaging data at the level of voxels, patients or sites in this multicenter clinical study.