This study proposes an electrohydrodynamic multiphysics modeling and finite element analysis technique to accurately simulate corona-streamer discharges in a two-phase flow medium. The discharge phenomenon is modeled as system, coupling the Poisson equation for electric field with charge dynamics model based on fluid methods thermofluid temperature effects. To optimize numerical simulation, tip-flat plate electrode was simplified two-dimensional axisymmetry, unordered lattice network used...

This paper presents a low-power stability strategy to significantly reduce the power consumption of three-stage amplifier using active-feedback frequency compensation (AFFC). The bandwidth can also be enhanced. Simulation results verify that dissipation AFFC is reduced by 43% and improved 32.5% proposed strategy. In addition, dynamic feedforward stage (DFS), which embedded into improve transient responses without consuming extra power, proposed. Implemented in 0.6-/spl mu/m CMOS process,...

Magnetic-thermal-fluidic analyses were conducted to assess the cooling performance of magnetic nanofluids by comparing with that transformer oil and air using fully coupled finite element method (FEM) considering magnetoconvection phenomena. Magnetic (MNFs) have been studied extensively for bio- nanotechnology applications. In particular, some studies reported MNF has good characteristics thermal management electric insulation in experiments. With this motivation, study focused on MNFs...

Surface discharge initiation and propagation on the surface of an insulating solid immersed in a dielectric liquid were examined numerically experimentally. To establish generalized numerical technique for evaluating phenomena using electrohydrodynamics (EHD) approach, we employed governing equations EHD, including Navier-Stokes equations. these coupled equations, added temporal charge equation accumulation liquid-solid interface, as well terms ionization, dissociation, recombination...

Abstract Because of their high electrical and thermal conductivities, copper-based alloys have recently experienced increased demand for use in leadframes. There is, however, a concern about the adhesion leadframes to epoxy molding compounds (EMCs), as poor has been partly responsible delamination cracking plastic packages during reflow soldering. In this study, leadframe sheets were oxidized brown-oxide and/or black-oxide forming solution improve strength between copper resin. The effects...

The discharge currents were evaluated and validated using the generalized energy method integral Ohm's law combined with recently developed analysis technique for dielectric liquid media, such as transformer oil. terminal current in voltage-driven systems was found to play an essential role characterizing pattern of electric discharge, corona, breakdown, etc. Until now, normally adopted evaluate this current, but no experimental validation reported test performed a media. can be derived...

This paper presents a high power efficient class-D audio amplifier. The proposed amplifier adopts the synchronized controlled oscillation modulator (SCOM), which is suitable for mobile applications. THD+N at half maximum output below 0.01% and efficiency better than 92% in an 8 /spl Omega/ speaker load. one-chip integrated circuit implemented 0.35 mu/m CMOS technology, with supply voltage range of 1.6 V-3.6 V. it occupies chip area 1.2/spl times/1.2 mm/sup 2/ dissipates only 1.3 mA idle.

In this paper, we proposed the digital watermarking for a color image. order to embed watermark signal, consider characteristics of HVS (human visual system) and focus on relatively insensitive components YCrCb space, Y component is achromatic--luminance both Cr Cb are chromatic--color. At Cr-Cb chrominance plane, an angle pixel represents hue that refers its average spectral wavelength differentiates different colors magnitude determines amount purity color. Because variation saturation...

A fully coupled Finite Element Analysis (FEA) technique was developed and tested to validate the cooling effects of a dielectric liquid stressed by an electric field, resulting in ionic dissociation phenomenon. Recently, electrohydrodynamics (EHD) techniques have been applied widely enhance performance electromagnetic systems introducing gaseous or media. The main advantage EHD is non-contact low-noise from smart control using field. In addition, some cases, flow can be achieved only field...

This paper describes an investigation into the combined effects of magnetoconvection and externally applied magnetic field on thermal performance vegetable oil-based nanofluids with different volume fractions nanoparticles. The mineral-based oil has conventionally been used in power transformers because it high dielectric strength good cooling under normal operating conditions. Because environmental impact, eco-friendly vegetable-based transformer oils have substituted for insulating oils....

This study presents an X-band complementary metal-oxide semiconductor-based frequency-modulation continuous-wave (FMCW) sensor system for transportation management. The proposed has two antennas, one to transmit signals and the other receive them. complete radio frequency (RF) transceiver is based on standard 0.18 µm one-poly six-metal (1P6M) CMOS technology with a chip area of 1.68 mm×1.6 mm. Two planar leaky-mode antenna arrays gain 18 dB are also designed. Experimental results indicate...

A major obstacle of the interdisciplinary communications for decision-making is that each participant prefers solution from their own area because current collaboration systems cannot effectively mediate among many alternatives. If a visual system could display multiple alternatives in single presentation, users would be able to compare with only few variables, where all other parameters are fixed, at least perspective. In this study, we developed visualization tool support microscale air...

A 12b pipelined ADC incorporating an improved timing scheme for high-speed operation achieves better than 60 dB SNDR input frequencies up to Nyquist at 120 Msample/s. The proposed improves the amplifier settling of MDACs and operating speed comparators. measured DNL INL are /spl plusmn/0.60 LSB plusmn/1.48 LSB, respectively. fabricated in a 0.13 mu/m CMOS process occupies 1.03 mm/sup 2/ active die area consumes 315 mW under 3.0V power supply.

Variable inductors using magnetorheological fluids have recently been successfully applied to power-conversion devices; however, the thermal properties of Vegetable oil-based Magnetic Nanofluids (VMNFs) not investigated. In this study, temperature characteristics a variable inductor embedded with VMNF were analyzed by developing multiphysics analysis method and verified experimentally. To analyze distribution efficiently, coupled Magnetoquasistatic (MQS) field steady-state heat transfer...

본 연구에서는 트리첼 펄스 코로나 특성을 분석하기 위해 침-셀 평판 전극 모델에서 고전계와 전하에 대 한 연속 방정식을 결합하여 유한요소법 기반의 전기-유체역학적 해석과 검증 실험을 수행하였다. 해석 모델은 고전계에 대한 푸아송 방정식과 전자, 양이온, 음이온 방정식으로 표현하여 검증된 상용화 도구인 COMSOL Multiphysics에 적용하여 전산 수치 해석하였다. 효율적인 유한요소해석을 전극을 2차원 축 대칭 차원에서 고전계-전하 운동장을 하나의 멀티피직스 시스템으로 수학적 모델링 하였다. 전류 해석은 부극성의 고전압이 인가된 침 전극에 2차 전자방출을 경계 조건으로 입력하고 일반화된 에너지법을 이용하여 계산하였다. 동일한 형상과 입력 조건에서 측정한 실 규모 실험 을 수행하여 연구에서 구축한 해석기법을 결과와 비교 검증하였다.