• 한국전기전자재료학회논문지
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• 제27권12호
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• pp.857-862
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• 2014

In this paper, we designed and fabricated electromagnetic induction based scaffold type energy harvester. For energy harvesting, mechanical energy of vertical motion is transferred to rotational energy using rack gear and multiplying gear was used to maximize energy transfer. To optimize design parameters, physical structure of energy harvester was modeled using finite element method. The effect of multiplying gear ratio and frequency levels of applied mechanical energy on energy generation efficiency are analyzed by computer simulation and experimental test. Experimental results showed that maximum 25.36 W of electric power can be achieved at the frequency of 2 Hz and 1:77 of gear ratio with only 5 mm of vertical changes on scaffold structure.

• 자원ㆍ환경경제연구
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• 제22권4호
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• pp.817-841
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• 2013

본 연구의 목적은 [2013 슬로푸드국제대회(아시오 구스토)] 개최의 경제적 타당성과 파급효과를 검증하는 데 있다. 이를 위하여 기존의 연구자료 및 통계자료를 활용하였으며, 국민여행실태조사와 대국민 설문조사를 통하여 수요추정을 하였다. 엑스포 개최 타당성을 검토하기 위하여 편익 비용 비율(Benefit Cost Ratio: BCR)과 순현재가치(Net Present Value: NPV)를 통해 재무적 및 경제적 타당성을 분석하였다. 또한, 엑스포 개최에 따른 경제적 파급효과를 추정하기 위하여 지역산업연관모형을 활용하여 전국 및 경기지역에 미치는 영향(효과)을 분석하였다. 재무적 타당성 분석 결과 BC ratio는 1.02~2.27로 수익성이 있는 것으로 나타났으며, 경제성 분석에서도 무료입장 10%적용시 시나리오 3과 4에서 BC ratio가 1.04~2.15로 나타나 수익성이 도출되었다. 한편, 엑스포 개최에 따른 남양주시를 포함한 경기도 지역경제의 파급효과는 생산유발효과가 373.6~738.7억 원, 부가가치유발효과가 166.2~327.4억 원, 고용유발효과는 1,971~2,009명으로 분석되었다. 따라서 "2013 슬로푸드국제대회"의 경제적 타당성은 양호한 것으로 나타났으며, 엑스포에 대한 지역주민의 공감대가 크며 남양주시 지역경제에 대한 경제적인 파급 효과도 긍정적인 것으로 나타났다.

• 자원리싸이클링
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• 제6권1호
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• pp.23-28
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• 1997

고주파 유도로에서 철캔, 석회석 슬러지, 폐줌루사, 석탄회, 그리고 폐유리병을 용융하여 철과 슬랙을 얻고 그 특성을 연구하였다. 직교 배열표를 이용하여 각 폐기물의 장입비가 최종 용융물의 물성에 미치는 영향을 조사하였다. 염기도 1.2에서 $\beta$-C$_2$S상과 $C_2$AS상이 주요한 상인 용융물이 생성되었으며 두 상의 분율은 폐기물 원료의 배합비율에 따라 변하였다. 철의 회수율은 93-95% 정도였으며 슬랙은 용출 및 압축시험 결과 일반 골재로서의 사용 가능성이 확인되었다.

• 조명전기설비학회논문지
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• 제28권1호
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• pp.114-122
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• 2014

This paper describes a study of the design conditions of a planar surface dielectric barrier discharge (DBD) reactors for generating negative air ions. The capacity of negative air ion generated by the surface DBD reactor is affected by the shape, area ratio and the location of the discharge and induction electrodes of it. To study the optimal design conditions of DBD reactors, the electrodes printed on the substrate of a PCB board is utilized to conduct kind of experiments: the distance of the each electrode along with the X-Y axis, the area ratio of the discharge electrode to induction electrode, and the symmetrical and asymmetrical location of two electrodes. The ion generation capacity is inverse proportional to the gap increases along with X-Y axis. And the optimum ion concentration generated by the ionizer was inspected when the electrodes area ratio was 3 and 5 times of the symmetrical and asymmetrical experimental condition respectively.

• 대한전기학회논문지
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• 제34권1호
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• pp.19-28
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• 1985

As is well known, the power equations of the N-node system have 2N-1 voltage solutions at most. The vlotage solutions are characterized by the introduction of the mode concept in this paper. There are two mode voltages at one node. One is defined as the (+) mode voltage and the other is defined as the (-) mode one. In this paper, we show that the (-) mode voltage responds to the increase of the power condenser almost adversly to the response of the (+) one. We study how to prevent the voltage collapse in the system with the induction motor load. The critical values of the gain and the time constant in case of the continuous power condenser control, and of the unit power condenser and the closing time delay in case of the discontinuous control for the prevention of the voltage collapse, are calculated. The effect of the composition ratio of the impedance load to the induction moter load on the above critical values are also investigated.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2001년도 추계학술발표대회
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• pp.333-335
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• 2001

A simple control strategy of DO-stat was introduced to the recombinant rGuamerin production process in Pichia pastoris. This induction strategy consisted of two interrelated control loops ‘by which oxygen ratio of inlet gas and methanol feeding rate was controlled. Using this control strategy, over-feeding or under-feeding of methanol could be avoided in concomitance with the efficient control of dissolved oxygen level. As a result, the cell concentration reached 130 g/L and rGuamerin expression level was 450 iu/L, which was more than 40% increased result comparing with the fed-batch process using manual control of methanol feeding rate.

• 전기학회논문지P
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• 제60권4호
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• pp.220-226
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• 2011

This paper proposes a straightforward method of analyzing the operation characteristics for the capacitor run single-phase induction motor from the traditional equivalent circuit based on the revolving field theory. The proposed method consists of five procedures as follows: mechanical loss segregation, iron loss segregation and calculation of the equivalent circuit parameters, recalculation of parameters of the main winding side, calculation of the auxiliary winding magnetizing reactance and effective turn ratio, and analyzing the operation characteristics for this motor. When the characteristics are analyzed, the segregated mechanical and iron losses are considered as a loss resistance across input terminals of the equivalent circuit for the analysis. The validity of the proposed method is verified from the comparison between the computed results and the experimental ones for the operation characteristics.

• Journal of Power Electronics
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• 제10권1호
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• pp.65-71
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• 2010

This paper presents the design and implementation of voltage source inverter type SVPWM based speed control of an induction motor using a fuzzy PI controller. This scheme enables us to adjust the speed of the motor by controlling the frequency and amplitude of the stator voltage; the ratio of the stator voltage to the frequency should be kept constant. A model of the fuzzy control system is implemented in real time with a Xilinx FPGA XC3S 400E. It is introduced to maintain a constant speed to when the load varies.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2003년도 춘계학술대회 논문집
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• pp.299-304
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• 2003

This paper proposes an algorithm to estimate the screw torque from parameters of induction motor and current of DC motor without strain gage and torque cell. The parameters of friction torque search for damping ratio and electromotive force constant use the motor torque and angula speed signals be generated in the induction motor, make use of oscilloscope and stroboscope for precise measured of experimental data, measured physical parameters through experimental. In addition the screw torque estimated use of measured current signals from induction moor. The results, theory and simulation recognized well coincidence.

• 전기학회논문지
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• 제57권9호
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• pp.1536-1545
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• 2008

In this paper, we research a new method for efficiency improvement of a single-phase Induction motor by minimization of the stator loss. To make this, we perform winding design which is based on balanced and quasi-balanced operation condition. It gives efficiency improvement greatly but poor starting torque simultaneously. To obtain the best efficiency improvement maintaining the maximum and starting torque, the optimal winding specification and rotor dimension is determined with variation of secondary resistance, running capacitor and turn ratio. Finally, this paper gives the comparison between the simulation results and experimental results.