Time filter

Source Type

Chen M.-J.,National Chiao Tung University | Lee C.-C.,National Chiao Tung University | Cheng K.-H.,Ministry of National Defense
IEEE Transactions on Electron Devices | Year: 2011

Self-consistently solving the Schrödinger and Poisson's equations in the six-band k · p context can yield the valence-band structure in the inversion layers of pMOSFETs. In this numerically demanding process, the central processing unit (CPU) time is extraordinarily long. To overcome the hurdle, we construct a novel computational accelerator to intrinsically boost a self-consistent six-band k · p simulation. This accelerator comprises a triangular-potential-based six-band k · p simulator, a hole effective mass approximation (EMA) technique, and an electron analogy version of the self-consistent Schrödinger and Poisson's equations solver. The outcome of the accelerator furnishes the initial solution of the confining electrostatic potential and is likely close to the realistic one, which is valid for different temperatures, substrate doping concentrations, inversion hole densities, and surface orientations. The results on (001) and (110) substrates are supported by those published in the literature. The overall CPU time is reduced down to around 8% of that without the accelerator. This is the first successful demonstration of the EMA in the self-consistent hole subband structure calculation. The application of the proposed accelerator to more general situations is projected as well. © 2011 IEEE.

Wai R.-J.,Yuan Ze University | Lin C.-Y.,Ministry of National Defense | Liaw J.-J.,Yuan Ze University | Chang Y.-R.,Institute of Nuclear Energy Research of Taiwan
IEEE Transactions on Industrial Electronics | Year: 2011

A newly designed zero-voltage-switching (ZVS) multi-input converter is proposed in this paper. The converter can boost the different voltages of two power sources to a stable output voltage. An auxiliary circuit is employed for achieving turn-on ZVS of all switches in the proposed converter. According to various situations, the operational states of the proposed converter can be divided into two states, including a single-power-supply and a dual-power-supply state. In the dual-power-supply state, the input circuits connected in series together with the designed pulsewidth modulation can greatly reduce the conduction loss of the switches. In addition, the effectiveness of the designed circuit topology and the ZVS properties are verified by experimental results, and the goal of high-efficiency conversion can be obtained. © 2011 IEEE.

Jeon S.-N.,Ministry of National Defense | Shin H.,Jeonju Kijeon College | Lee H.-J.,Yonsei University
Osong Public Health and Research Perspectives | Year: 2012

Objectives: This study examined components in Rowe and Kahn's successful aging model to investigate their hierarchical order and led to a modification of the previous hierarchical order. Methods: To examine the hierarchical order of components, we constructed a structural equation model and verified those paths that have discrepancies in studies and/or potential inclusion or omission errors in the model. For this purpose, we analyzed 556 cases out of stratified and purposively sampled 600 elderly people living in the city of Jeonju during the study period (2011). Results: The paths with inclusion errors such as H3 [self-reported health → productive activity (SRH → PA)]: the effect of SRH on PA, and H6 [social network (SN) → PA]: the effect of SN on PA, were not directly but indirectly supported. The path with discrepancy, H4 [SN → physical-cognitive function (PCF)]: the effect of SN on PCFs, was statistically significant. The path with inclusion error and discrepancy, H8 (PCF → PA): the effect of PCF on PA, was not directly but indirectly supported. Also the path with the omission error, H2 [SRH → psychological trait (PT)]: the effect of SRH on PT, was statistically significant. The other paths in the hierarchical order of the model reported in previous studies were statistically significant. Conclusion: We verified new dynamics of constructs involved in successful aging, which would provide better understanding of Rowe and Kahn's successful aging model for Korean elderly people living in a medium-sized city. © 2012.

Hsu C.-Y.,National Chiao Tung University | Chang H.-G.,Ministry of National Defense | Chen M.-J.,National Chiao Tung University
IEEE Transactions on Electron Devices | Year: 2011

For metal-gate high-k dielectrics, there is a transition region in the electron gate tunneling current Ig, as characterized by a plot of dlnIg/dVg versus Vg. In this paper, we systematically construct a new fitting over the region, which can accurately determine material parameters, including metal work function, high-k electron affinity, and tunneling effective masses of electrons. First of all, a calculation of gate current due to electron direct tunneling and/or FowlerNordheim tunneling from an inversion layer is performed, yielding the guidelines of the fitting. Experimental samples are presented with n-channel metaloxidesemiconductor field-effect transistors having low effective oxide thickness (1.4 nm) TaC/HfSiON/SiON gate stacks. Underlying material parameters are extracted accordingly and remain valid for higher temperature and gate voltage. We also demonstrate that a conventional method without a dlnI g/dVg fitting might lead to erroneous results. Thus, the dlnIg/dVg fitting is crucial to metal-gate high-k material parameter assessment. © 2011 IEEE.

Wai R.-J.,Yuan Ze University | Lin C.-Y.,Ministry of National Defense
IEEE Transactions on Industrial Electronics | Year: 2011

This paper focuses on the design of a dual active low-frequency ripple control for a clean-energy power-conditioning mechanism with an aim to achieve both the alleviation of the low-frequency current ripple of clean-energy sources (e.g., solar photovoltaic, fuel cell, etc.) and the improvement of the ac power quality of a power conditioner. First, a simplified circuit for representing both the current-ripple phenomena at the high-voltage bus and the polluted ac output terminal inside a general power conditioner, including a dc-dc converter and a dc-ac inverter, is derived, and the dynamic model of a dual active low-frequency ripple control circuit is analyzed. Moreover, two adaptive linear neural networks are taken as neural filters to generate the compensation current commands, and an adaptive total sliding-mode controller is designed to manipulate the ripple control circuit for injecting respective suitable compensation currents into the high-voltage bus and the ac output terminal of the conditioner. In addition, the effectiveness of the proposed dual active low-frequency ripple control framework is verified by numerical simulations and experimental results. © 2006 IEEE.

Discover hidden collaborations