共查询到20条相似文献，搜索用时 15 毫秒
1.
Sicheng Liao Mitra Dutta Dan Schonfeld Takayuki Yamanaka Michael A. Stroscio 《Journal of Computational Electronics》2008,7(3):462-465
In designing nanoscale optoelectronic devices based on a small number of active quantum dots, it is of interest to consider
that semiconductor nanocrystals (quantum dots) are observed to blink “on” and “off”. The time probability distributions scale
as an inverse power law for colloidal quantum dots and exponentially for self-assembled dots. Possible mechanisms that cause
the inverse power law and exponential blinking statistics are discussed in the paper and the relevance to quantum-dot based
system architectures is discussed. 相似文献
2.
Marcello Pesare Agostino Giorgio Anna Gina Perri 《International Journal of Numerical Modelling》2001,14(5):395-409
In this paper, an analytical model for the electrothermal solution to the non‐linear 3‐D heat flow equation for multilayer structure electronic devices is proposed. Compared with previous models presented in literature, it is general and can be easily applied to a large variety of integrated devices, provided that their structure can be represented as an arbitrary number of superimposed layers with a 2‐D embedded thermal source, so as to include the effect of the package. The proposed method is independent of the specific physical properties of the layers, hence GaAs MESFETs and HEMTs as well as silicon and silicon‐on‐insulator MOSFETs and heterostructure LASERs can be analysed. Moreover, it takes into account the dependence of the thermal conductivity of all the layers on the temperature; the heat equation is solved coupled with the device current–voltage relation in order to give physical consistence to the experimental evidence that a temperature increase causes a degradation of the electrical performances and that the electrical power is not uniformly distributed. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
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在光电子器件封装中,光纤组件和阵列波导芯片之间微小位移的检测对封装效率有很大的影响。分析了目前光电子封装存在的问题,并对几种位移测量方法进行了比较,提出了基于电阻应变式一维位移传感器结构。首先,对位移传感器结构进行了理论上的分析,得到了微位移与应变的关系式;然后,采用 ANSYS有限元分析软件对传感器的结构的进行仿真分析,得到位移与应变之间的仿真值;最后,把理论上的分析值与仿真得到的结果进行比较分析。结果表明,新型传感器能够检测微米级位移,通过优化弹性薄片的结构和改变施力点的位置,可以有效的提高传感器的灵敏度。 相似文献
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Roberto Diana Agostino Giorgio Anna Gina Perri 《International Journal of Numerical Modelling》2005,18(5):365-382
We present a new, very accurate and fast model of photonic bandgap (PBG) structure characterized by a two‐dimensional (2D) periodic change of the refractive index and finite height, therefore named quasi 3D PBG. The new model is based on the Floquet–Bloch formalism and allows to find all the propagation characteristics including the space harmonics and the total field distribution, the propagation constants, the guided and radiated power and modal loss induced by the 2D grating. A clear explanation of the physical phenomena occurring when a wave propagates inside the 2D periodic structure is presented, including the photonic bandgap formation and the radiation effects. The approach does not require any theoretical approximation, and can be applied to study rigorously any PBG‐based multilayer structures. We have applied the model to investigate several structures for both optical and microwave applications. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
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Agostino Giorgio Anna Gina Perri Mario Nicola Armenise 《International Journal of Numerical Modelling》2001,14(6):507-522
A model of deeply and fully etched gratings (also identified as one‐dimensional waveguide photonic bandgap structures), based on the Bloch–Floquet theorem, has been developed to perform a complete analysis of the electromagnetic (e.m.) wave propagation in the structure, assumed of finite extension, i.e. to determine mode propagation constants, electromagnetic field harmonics and total field distribution, transmission and reflection coefficients, total forward and backward power flow in the structure, guided power and total losses. Comparisons with other accurate numerical methods confirm the accuracy of the new one, whose main advantages are the quickness and the possibility to determine a great amount of information and figures of merit in a few seconds (for each operating wavelength). Moreover, the model allows the designer a complete view of the physical and geometrical device features, so it permits to draw design rules for optimization of photonic bandgap (PBG) waveguide device design. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
6.
Hatem Garrab Bruno Allard Herv Morel Sami Ghedira Kamel Besbes 《International Journal of Numerical Modelling》2004,17(6):539-560
Electro‐thermal simulations of a PIN‐diode based on the finite‐element method, show a non‐uniform temperature distribution inside the device during switching transients. Hence, the implicit assumption of a uniform temperature distribution when coupling an analytical electrical model and a thermal model yields inaccurate electro‐thermal behaviour of the PIN‐diode so far. The idea of including non‐uniform temperature distribution into power semiconductor device models is not new, as accurate electro‐thermal simulations are required for designing compact power electronic systems (as IC or MCM). Instead of using a one‐dimensional finite difference or element method, the bond graphs and the hydrodynamic method are utilized to build an electro‐thermal model of the PIN‐diode. The results obtained by this original technique are compared with those obtained by a commercial finite‐element simulator. The results are similar but the computation effort of the proposed technique is a fraction of that required by finite‐element simulators. Moreover, the proposed technique may be applied easily to other power semiconductor devices. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
7.
Agostino Giorgio Decio Pasqua Anna Gina Perri 《International Journal of Numerical Modelling》2004,17(2):85-103
The fibre optic transmission systems require a bandwidth of about 25 THz in telecommunications networks, for which it is necessary to resort to dense wavelength division multiplexing (DWDM) systems. These systems need optical filters to broadcast selectively or not in a given wavelength band. A new very promising technology for these applications is the photonic crystals with forbidden bandgap (photonic bandgap (PBG)). In this paper, we propose a model of PBG devices to design DWDM filters on PBG materials. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
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Recent trends in compact device modelling and circuit simulation suggest a growing movement towards standardization of Verilog‐A as a vehicle for semiconductor device specification and model interchange among commercial and open source simulators. This paper introduces a nonlinear equation‐defined device (EDD) characterized by current, voltage and charge equations with a similar syntax to Verilog‐A. The EDD has been implemented in Qucs and used extensively as a central feature in an interactive modelling system that allows straightforward prototyping of compact device models prior to translation into Verilog‐A. To illustrate the properties and the use of the Qucs EDD a number of examples centred on well‐known SPICE models are described. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
9.
J. H. Graven R. A. M. van Amerongen 《International Journal of Electrical Power & Energy Systems》1986,8(4):241-247
A decoupled state estimation algorithm is proposed in which the measurement model is based on linear approximation of the power flow equations and the solution method is based on linear programming. The decoupled least-squares DC-estimator and the undecoupled least-absolute-value estimator are numerically compared. As an overall reference, the classic undecoupled least-squares estimator is used. The error-detecting capabilities and the accuracy of the estimated state of all four types of estimators are treated. 相似文献
10.
G. P. T. Roelofs 《International Journal of Electrical Power & Energy Systems》1989,11(4):289-292
This paper describes the influence of the electrical load model on the behaviour of an electrical power system. Seven different load models have been selected and the impact of these models on four aspects of the behaviour of the network has been investigated. The investigation has been performed on the 220 and 110 kV FGO grid, which forms part of the Dutch high-voltage network. If, for a specific study, the nature of the load is unknown, it is recommended to use a load model in which the active and reactive parts are presented by a constant admittance. 相似文献
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油井抽油机示功仪的研制 总被引：2，自引：0，他引：2
介绍了一种以89C51单片机为核心器件的抽油机示功仪的组成及其工作原理。该示功仪通过检测光杆位移等间隔采样光杆载荷,得到一组光杆载荷数据,并对数据进行3△滤波,通过微型打印机打印示功图。 相似文献
13.
近年来,随着大型光电设备的应用需求不断增加,其稳定可靠的驱动方法逐渐成为研究热点。直流有刷电机因为具 有非线性周期转矩波动和大电流引起的电磁干扰等固有缺点,已经无法满足设备体量不断增大的需求。永磁同步电机作为 一种技术成熟的电机,具有运行稳定,输出力矩大,可靠性高等特点,逐渐成为大型光电设备驱动电机的一种优选方案。评估 大型光电设备中永磁同步电机的性能,以确保其在高精度光电系统中的性能和可靠性。通过设置模拟实际工作环境,采用标 准化测试流程对永磁同步电机进行测试,重点关注其速度阶跃指标和平稳性的测试。测试结果表明,永磁同步电机在速度阶 跃过程中超调量低于15%,稳定时间优于0.4s; 低速运行时的速度波动均能达到设备使用要求。可见,永磁同步电机在大型 光电设备应用中表现出高效的性能和良好的可靠性,可作为大型光电设备驱动单元的优选方案。 相似文献
14.
A simple upwind discretization of the highly coupled non‐linear differential equations which define the hydrodynamic model for semiconductors is given in full detail. The hydrodynamic model is able to describe inertia effects which play an increasing role in different fields of opto‐ and microelectronics. A silicon n+−n−n+‐structure is simulated, using the energy‐balance model and the full hydrodynamic model. Results for stationary cases are then compared, and it is pointed out where the energy‐balance model, which is implemented in most of today's commercial semiconductor device simulators, fails to describe accurately the electron dynamics. Additionally, a GaAs n+−n−n+‐structure is simulated in time domain in order to illustrate the importance of inertia effects at high frequencies in modern submicron devices. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
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王国华 《电力系统保护与控制》2004,32(21):67-68
介绍一种用110～220kV线路电压抽取装置检测35kV线路电压(供备自投使用)的方法。实践证明该法简单、可行、节省投资和安装空间,在老站进行综合自动化改造中,该方法尤为适用。 相似文献
19.
基于光电检测技术的玻璃间距测量方法的研究 总被引：1，自引：2，他引：1
本文主要研究基于光电检测技术的透明玻璃间距测量方法和实验装置。本测量系统由激光光源、光学系统、图像采集系统及光点位置估算系统组成。本文主要讨论了采用重心估算（CCP）傅立叶相位偏转法（FPS）计算光点的位置。此外,为了验证上述理论的可行性,本研究利用计算机软件模拟并讨论了噪声信号对上述2种光电估算法的影响。数值仿真结果显示信号中的直流分量和背景噪声对CCM方法的仿真精度的影响要比FPS大;当光斑分别为艾里图样和高斯图样时,CCM方法和FPS方法的计算精度基本相同。 相似文献