• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 E
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• pp.2035-2037
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• 1999

This paper describes an ASM(All Solid-state Modulator) pulsed power generator for non-thermal plasma applications. The proposed generator can produce 20kV, 500A, 100ns pulses at repetition rates up to 10kHz, and it is composed of 30 series connections of power circuit card assembly which contains paralleled MOSFETs, MOSFET drivers, energy storage capacitors and specially designed 1:1 pulse transformer. Higher pulse voltages and currents can easily be obtained by increasing the numbers of series and parallel connections of power circuit card and MOSFETs, respectively. Component layouts are optimized to minimize the leakage inductance and the voltage spikes across switching devices. Especially it put emphasis on the over-current protection (including short circuit) for the reliable operation in real situations. Experimental results show that the proposed pulser is very efficient in air pollution control application and could be useful for other applications such as synthesis of nanosize powders and non-thermal food processing.

• ETRI Journal
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• 제36권4호
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• pp.519-527
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• 2014

An integrated multi-beam satellite and multi-cell terrestrial system is an attractive means for highly efficient communication due to the fact that the two components (satellite and terrestrial) make the most of each other's resources. In this paper, a terrestrial component reuses a satellite's resources under the control of the satellite's network management system. This allows the resource allocation for the satellite and terrestrial components to be coordinated to optimize spectral efficiency and increase overall system capacity. In such a system, the satellite resources reused in the terrestrial component may bring about severe interference, which is one of the main factors affecting system capacity. Under this consideration, the objective of this paper is to achieve an optimized resource allocation in both components in such a way as to minimize any resulting inter-component interference. The objective of the proposed scheme is to mitigate this inter-component interference by optimizing the total transmission power - the result of which can lead to an increase in capacity. The simulation results in this paper illustrate that the proposed scheme affords a more energy-efficient system to be implemented, compared to a conventional power management scheme, by allocating the bandwidth uniformly regardless of the amount of interference or traffic demand.

• 한국전기전자재료학회논문지
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• 제17권7호
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• pp.782-787
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• 2004

Superconducting flux flow transistor (SFFT) is based on a control of the Abrikosov vortex flowing along a channel. The induced voltage by moving of the Abrikosov vortex in an SFFT is greatly affected by the thickness, the width, and the length of channel. In order to fabricate a reproducible channel in the SFFT, we studied the variation of the critical characteristics of ${YBa}_2{Cu}_3{O}_7-\delta(YBCO)$ thin films with the etching time using ICP (Inductively coupled plasma) system. From the simulation, it was certified that the vortex velocity was increased in a low pinning energy at channel width 0,5 mm. The surfaces of YBCO thin film were etched by ICP etching system. We observed the etched channel surfaces by AFM (Atomic Force Microscope) and measured the critical current density with etching time. As a measured results, the etching thickness of channel should be optimized to fabricated a flux flow transistor with specified characteristics.

• 조명전기설비학회논문지
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• 제23권12호
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• pp.1-9
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• 2009

최근 실내에 유입된 주광을 활용하여 인공조명의 에너지를 절감하는 광센서 조광제어시스템에 관한 연구는 유용한 주광의 유입을 위한 자동 차양장치와의 통합을 중심으로 이루어지고 있다. 기존의 연구는 자동 롤러쉐이딩시스템과 베니션블라이드에 관한 연구로, 이 두 시스템은 주광의 입사를 수직적으로 계산한 일영각을 기준으로 차양장치의 높이 및 각도를 계산하여 제어하고 있다. 본 연구는 광센서 조광제어시스템과 연동을 위한 새로운 차양장치로 주광의 유입을 수직 수평으로 제어하는 복층유리 격자루버시스템을 제안하고, 창면의 위치에 따른 루버의 간격을 산출하였으며, 컴퓨터 시뮬레이션을 통하여 격자루버시스템의 주광유입특성을 분석하고 평가하였다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.319.1-319.1
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• 2013

Solid oxide fuel cells (SOFCs) have been recognized as one of emerging renewable energy sources, due to minimized pollutant production and high efficiency in operation. The performance of SOFCs is largely dependent on the electrode polarization which involves the oxidation/reduction in cathodes and anodes along with the charge transport of ions and electronic carriers. Atomic layer deposition is based on the alternate chemical surface reaction occurring at low temperatures with high uniformity and superior step coverage. Such features can be extended into the coating of metal oxide and/or metal layer onto the porous materials. In particular, the atomic layer deposition is can manipulated in controlling the charge transport in terms of triple phase boundaries, in order to control artificially the electrochemical polarization in electrodes of SOFC. The current work applied atomic layer deposition of metal oxides intro the electrodes of SOFCs. The corresponding effect was monitored in terms of the electrochemical characterization. The roles of atomic layer deposition in solid oxide fuel cells are discussed towards optimized towards long-term durability at intermediate temperature.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.349-353
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• 2004

A study on optimal placement of constrained layer damping treatment for vibration control of automotive panels is presented. The effectiveness of damping treatment depends upon design parameters such as choice of damping materials, locations and size of the treatment. This paper proposes a CAE (Computer Aided Engineering) methodology based on finite element analysis to optimize damping treatment. From the equivalent modeling technique, it is found that the best damping performance occurs as the viscoelstic patch is placed by means of the modal strain energy method of bare structural panels to identify flexible regions, which in turn facilitates optimizations of damping treatment with respect to location and size. Different configurations of partially applied damping layer treatment have been analyzed for their effectiveness in realizing maximum system damping with minimum mass of the applied damping material. Moreover, simulated frequency response function of the automotive roof with and without damping treatments are compared, which show the benefits of applying damping treatment. Finally, the optimized damping treatment configuration is validated by comparing the locations and the size of the treatment with that of an experimental modal test conducted on roof compartment.

• Corrosion Science and Technology
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• 제21권1호
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• pp.32-40
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• 2022

The o-Vanillin - Glutamine Schiff base [2-Hydroxy-3-Methoxy BenzylidineCarbomyl) -2-Butanoic Acid] was examined for low carbon steel corrosion inhibition in acid media. Weight loss studies were carried out at three different temperatures to determine the inhibition efficiency (IE). Electrochemical impedance spectroscopy revealed that the charge transfer resistance controlled the corrosion reaction and Tafel polarization indicated that the Schiff base acts as mixed mode of inhibitor. SEM images were recorded for the surface morphology of the low carbon steel surface. DFT studies revealed corrosion control mechanisms using quantum chemical parameters such as E_HOMO, E_LUMO, energy gap (∆E), chemical Hardness (η), chemical Softness (σ), Electronegativity (χ), and the fraction of electron transferred (∆N), which is calculated using Gaussian software 09. The gas-phase geometry was fully optimized in the Density Functional Theory (DFT/B3LYP-6-31G (d)).The DFT results are in good agreement with the experimental results. All the results proved that the Schiff Base (2-Hydroxy-3-Metoxy BenzylidineCarbomyl) -2-Butanoic is a suitable alternative for corrosion inhibition of low carbon steel in acid media.

• 자동차안전학회지
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• 제14권1호
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• pp.55-61
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• 2022

Along with global environmental issues, the size of the electric vehicle market has recently skyrocketed. Various efforts have been made to extend mileage, one of the biggest problems of the electric vehicles, and development of batteries with high energy densities has led to exponential growth in mileage and performance. However, proper thermal management is essential because these high-performance batteries are affected by continuous heat generation and can cause fires due to thermal runaway phenomena. Therefore, thermal management of the battery is studied through the optimal design of the guide vanes, while utilizing the existing battery casing to ensure the safety of the electric vehicles. A battery from T-company, one of a manufacturer of the electric vehicles, was used for the research, and the commercial CFD software, ANSYS CFX V20.2, was used for analysis. The guide vanes were derived through optimal design based on a genetic algorithm with flow analysis. The optimized guide vanes show improved heat removal performance.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2012년도 춘계학술대회
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• pp.378-379
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• 2012

현재 에너지 소비가 증가하면서 환경적인 이슈로 전력 산업의 고도화 및 에너지 효율화에 대한 요구가 증가함에 따라 지능형 전력시스템과 같은 전력 IT 산업이 신 성장 동력으로 주목받고 있다. 지능형 전력 시스템을 통해 전력 수요에 따른 공급의 밸런스를 최적화하게 되면 에너지 수입 및 전력 인프라 건설, 운영에 소요되는 막대한 비용을 절감할 수 있고, 안정적으로 전력을 공급할 수 있게 된다. 하지만, 모든 설비 및 장비를 실시간 관리하기 위해서는 인력낭비가 발생할 뿐만 아니라, 응급 상황을 인지하지 못해 전력사고로 이어지는 문제가 발생할 수 있다. 따라서, 본 논문에서는 스마트폰 기반의 원격 제어 및 모니터링 기능을 구비한 지능형 수배전반 통합관리 시스템을 개발하였다. 기존의 수배전반 관리 시스템의 단점을 보완한 본 시스템은 저비용으로 효율성과 안정성을 대폭 향상 시킬 수 있어, 향후 전력 IT 산업의 발전에 크게 도모할 수 있을 것으로 판단된다.

• 한국수소및신에너지학회논문집
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• 제23권6호
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• pp.670-677
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• 2012

Perovskite-type oxides such as doped barium zirconate ($BaZrO_3$) show high proton conductivity and chemical stability when they are exposed to hydrogen and water vapour containing atmospheres, thus it can be applicable to the hydrogen separation and the fuel cell electrolyte membranes. However the high temperature ($1700-1800^{\circ}C$) and long sintering times (24h) are generally required to prepare the fully densified $BaZrO_3$ pellets. These sintering conditions lead to the limitation of the grain size growth and the degradation of conductivity due to the acceleration of BaO evaporation at $1200^{\circ}C$. Here we demonstrate NiO-doped $BaZr_{0.85}Y_{0.15}O_{3-{\delta}}$ with lower calcination and sintering temperature, less experimental procedure and lower process cost than the conventional mixing method. The stoichiometry of $BaZr_{0.85}Y_{0.15}O_{3-{\delta}}$ was optimized by the control of excess amount of Ba (5mol%) to minimized BaO evaporation. We found that the crystal size of NiO-doped $BaZr_{0.85}Y_{0.15}O_{3-{\delta}}$ was increased with increase of calcination temperature from XRD analysis. NiO-doped $BaZr_{0.85}Y_{0.15}O_{3-{\delta}}$ powder was calcined at $1000^{\circ}C$ for 12h when its showed the highest conductivity of $3.3{\times}10^{-2}s/cm$.