The Experts below are selected from a list of 292752 Experts worldwide ranked by ideXlab platform

Kaustav Banerjee - One of the best experts on this subject based on the ideXlab platform.

  • high Frequency Behavior of graphene based interconnects part ii impedance analysis and implications for inductor design
    IEEE Transactions on Electron Devices, 2011
    Co-Authors: Deblina Sarkar, Kaustav Banerjee
    Abstract:

    This paper provides the first detailed insights into the ultrahigh-Frequency Behavior of graphene ribbons (GRs) and analyzes their consequences in designing interconnects and low-loss on-chip inductors. In the companion paper (part I), an accurate impedance modeling methodology has been developed based on the Boltzmann equation with the magnetic vector potential Green's function approach incorporating the dependency of current on the nonlocal electric field. Based on the developed methodology, this paper for the first time embarks on the rigorous investigation of the intricate processes occurring at high frequencies in GRs, such as anomalous skin effect (ASE), high-Frequency resistance and inductance saturation, intercoupled relation between edge specularity and ASE, and the influence of the linear dimensions on impedance. A comparative study of the high-Frequency response of GRs with that of carbon nanotubes (CNTs) and Cu is made to highlight the potential of GR interconnects for high-Frequency applications. Subsequently, the high-Frequency performance of GR inductors is analyzed, and it is shown that they can achieve 32% and 50% improvements in maximum Q-factor compared to Cu and single-walled CNT inductors with 1/3 metallic fraction, respectively.

  • high Frequency Behavior of graphene based interconnects part i impedance modeling
    IEEE Transactions on Electron Devices, 2011
    Co-Authors: Deblina Sarkar, Kaustav Banerjee
    Abstract:

    This paper presents the first detailed methodology for the accurate evaluation of high-Frequency impedance of graphene-based structures relevant to on-chip interconnect and inductor applications. Going beyond the simplifying assumptions of Ohm's law, the effects of electric-field variation within a mean free path and current dependency on the nonlocal electric-field are taken into account to accurately capture the high-Frequency Behavior of graphene ribbons (GRs). At the same time, a simplified approach that may be adopted at lower frequencies is also explained. Starting from the basic Boltzmann equation and combining with the unique dispersion relation for graphene in its hexagonal Brillouin zone, the current density across the GR structure is derived. First, a semi-infinite slab of GR is analyzed using the theory of Fourier integrals, which is followed by the development of a rigorous methodology for practical finite structures based on a self-consistent numerical calculation of the derived current density using the Green's function approach.

S Y R Hui - One of the best experts on this subject based on the ideXlab platform.

  • actively clamped bidirectional flyback converter
    IEEE Transactions on Industrial Electronics, 2000
    Co-Authors: Gang Chen, Yimshu Lee, S Y R Hui, Y Wang
    Abstract:

    An actively clamped bidirectional flyback converter is proposed. The converter's operation is examined in detail. All switches in the converter have zero-voltage-switching characteristics. A low-Frequency Behavior model and small-signal transfer functions are derived. It is found that the flow of current is directly under the control of the duty cycle, and that the transformer's leakage inductance has a significant effect on the control characteristic of the converter. It is expected that such bidirectional converters will find wide applications in the interconnection of multiple sources of DC power to a common bus (e.g., in a DC uninterruptible power supply). Simulation and experiment results are also presented.

  • modeling analysis and application of buck converters in discontinuous input voltage mode operation
    IEEE Transactions on Power Electronics, 1997
    Co-Authors: Y S Lee, S J Wang, S Y R Hui
    Abstract:

    By adding a suitable LC filter to the input of a buck power converter, it is possible to force the converter into discontinuous-input-voltage mode operation. A buck power converter in this mode of operation has useful properties such as power factor correction and soft turn-off switching. The operation, modeling, low-Frequency Behavior, and application of the power converter are studied. Experimental results verifying the theoretical predictions are also presented.

Deblina Sarkar - One of the best experts on this subject based on the ideXlab platform.

  • high Frequency Behavior of graphene based interconnects part ii impedance analysis and implications for inductor design
    IEEE Transactions on Electron Devices, 2011
    Co-Authors: Deblina Sarkar, Kaustav Banerjee
    Abstract:

    This paper provides the first detailed insights into the ultrahigh-Frequency Behavior of graphene ribbons (GRs) and analyzes their consequences in designing interconnects and low-loss on-chip inductors. In the companion paper (part I), an accurate impedance modeling methodology has been developed based on the Boltzmann equation with the magnetic vector potential Green's function approach incorporating the dependency of current on the nonlocal electric field. Based on the developed methodology, this paper for the first time embarks on the rigorous investigation of the intricate processes occurring at high frequencies in GRs, such as anomalous skin effect (ASE), high-Frequency resistance and inductance saturation, intercoupled relation between edge specularity and ASE, and the influence of the linear dimensions on impedance. A comparative study of the high-Frequency response of GRs with that of carbon nanotubes (CNTs) and Cu is made to highlight the potential of GR interconnects for high-Frequency applications. Subsequently, the high-Frequency performance of GR inductors is analyzed, and it is shown that they can achieve 32% and 50% improvements in maximum Q-factor compared to Cu and single-walled CNT inductors with 1/3 metallic fraction, respectively.

  • high Frequency Behavior of graphene based interconnects part i impedance modeling
    IEEE Transactions on Electron Devices, 2011
    Co-Authors: Deblina Sarkar, Kaustav Banerjee
    Abstract:

    This paper presents the first detailed methodology for the accurate evaluation of high-Frequency impedance of graphene-based structures relevant to on-chip interconnect and inductor applications. Going beyond the simplifying assumptions of Ohm's law, the effects of electric-field variation within a mean free path and current dependency on the nonlocal electric-field are taken into account to accurately capture the high-Frequency Behavior of graphene ribbons (GRs). At the same time, a simplified approach that may be adopted at lower frequencies is also explained. Starting from the basic Boltzmann equation and combining with the unique dispersion relation for graphene in its hexagonal Brillouin zone, the current density across the GR structure is derived. First, a semi-infinite slab of GR is analyzed using the theory of Fourier integrals, which is followed by the development of a rigorous methodology for practical finite structures based on a self-consistent numerical calculation of the derived current density using the Green's function approach.

S Ramanathan - One of the best experts on this subject based on the ideXlab platform.

  • identification of reaction mechanism for anodic dissolution of metals using electrochemical impedance spectroscopy
    Journal of Electroanalytical Chemistry, 2010
    Co-Authors: Jeevan Maddala, Krishnaraj Sambath, Vinod Kumar, S Ramanathan
    Abstract:

    Electrochemical Impedance Spectroscopy (EIS) is a sensitive technique for determining the mechanistic pathway of an electrochemical reaction. In particular, the low Frequency Behavior of the impedance at various over-potentials can help differentiate between very similar mechanisms. Nine different mechanisms related to anodic dissolution of metals are simulated and the EIS patterns that are expected for these mechanisms are identified. This library of patterns reported here will help in eliminating certain mechanisms and identifying mechanisms with the least number of parameters that can be applied for modeling experimental EIS data.

Mark Omalley - One of the best experts on this subject based on the ideXlab platform.

  • an assessment of the impact of wind generation on system Frequency control
    IEEE Transactions on Power Systems, 2010
    Co-Authors: Ronan Doherty, A Mullane, Garry P Nolan, Daniel J Burke, Alexander Bryson, Mark Omalley
    Abstract:

    Rising wind generation penetrations and the distinctive inertial characteristics of associated turbine technology will impact system Frequency control. While wind production will displace conventional synchronous plant, empirical study data presented also suggest that the relationship between the total stored turbine kinetic energy and the total system power production for wind is a variable that exhibits significant nonlinearity. Changing trends in system Frequency Behavior of a power system following the loss of the largest generator are studied in detail here, using simplified Frequency control models and extensive simulations of wind penetration scenarios over an extended multiyear timeframe. The system Frequency response is characterized by the rate of change of Frequency and the Frequency nadir. Results show that increasing levels of doubly fed induction generators and high-voltage dc interconnection alter the Frequency Behavior significantly, and that system operators may have to be proactive in developing solutions to meet these challenges.