• 한국융합학회논문지
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• 제7권3호
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• pp.77-85
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• 2016

음향 전력 증폭기의 출력단에서 발생하는 비선형성을 보상하는 디지털 신호 처리 기술을 제안하고 그 모의실험 결과를 제시한다. 음향 전력 증폭기에 사용되는 소자에 의한 비선형성을 간접학습구조와 적응형 필터로 구성되는 디지털 신호 처리 기술로 보상한다. 적응형 필터를 사용함으로써 증폭기의 비선형 특성이 시간적으로 변하더라도 이를 적응적으로 보상할 수 있다. 모의실험 결과 전치 보상기는 3 차의 다항식으로 구현할 수 있으며 홀수차 비선형성을 효과적으로 제거할 수 있음을 보였다. 짝수 차 비선형은 출력 신호에 존재하는 직류 옵셋이 가장 큰 부분을 차지하며 이는 제안하는 기술로는 제거가 어려우므로 바이어스 회로 설계 시 유의해야 한다. 제안하는 기술은 아날로그 시스템의 본질적 특성 결함을 디지털 신호 처리 기술로서 보상할 수 있음을 보여준다.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2005년도 추계학술발표대회 논문집
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• pp.103-106
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• 2005

The material properties of membrane for stratospheric airship is experimentally investigated. Mechanical tensile properties of the membrane material at room, high and low temperature are measured using instron with thermal chamber. Experimentaly, material non-linearity is observed at room and high temperature. In order to simulate material non-linearity caused by the uniaxial extension curve of a woven fabric, the nonlinear hyperelastic problem is considered with finite clement program of ABAQS. Numerical results are compared with experimental results.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2000년도 제32회 추계학술대회 정기총회
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• pp.243-249
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• 2000

In case of the limitation of Deep RIE fabrication for Micro Gas Turbine, bearing aspect ratio is limited in very small value. The characteristics such as pressure distribution load capacity and non-linearity of a short bearing of L/D=0.083 and a conventional bearing of L/D=1.0 with coupled boundary effects are investigated far Micro Gas Tlubine bearings. The coupled efffect was analyzed by mass conservation at coupled end area. The results, increasing load capacity and non-linearity due to the coupled effect of thrust and journal bearing, are obtained and the selection of journal bearing type is discussed.

• 한국전기전자재료학회논문지
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• 제16권9호
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• pp.790-794
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• 2003

This paper describes the fabrication and characteristics of ceramic thin film type pressure sensors based on Ta-N strain gauges for high temperature applications. Ta-N thin-film strain gauges are deposited onto a thermally oxidized Si diaphragm by RF sputtering in an argon-nitrogen atmos[here($N_2$ gas ratio: 8%, annealing condition: 90$0^{\circ}C$, 1 hr.), patterned on a wheatstone bridge configuration, and used as pressure sensing elements with a high stability and a high gauge factor. The sensitivity is 1.097 ～ 1.21 mV/Vㆍkgf/$\textrm{cm}^2$ in the temperature range of 25 ～ 200 $^{\circ}C$ and the maximum non-linearity resistance), non-linearity than existing Si piezoresistive pressure sensors. The fabricated ceramic thin-film type pressure sensor is expected to be usefully applied as pressure and load sensors that os operable under high-temperature.

• KSTLE International Journal
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• 제1권2호
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• pp.107-112
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• 2000

In case of the limitation of Deep RIE fabrication far Micro Gas Turbine, bearing aspect ratio is limited in very small value. The characteristics such as pressure distribution, load capacity and non-linearity of a short bearing of L/D=0.083 and a conventional bearing of L/D=1.0 with coupled boundary effects are investigated for Micro Gas Turbine bearings. The coupled effect was analyzed by mass conservation at coupled end area. The results, increasing load capacity and non-linearity due to the coupled effect of thrust and journal bearing, are obtained and the selection of journal bearing type is discussed.

• 한국전기전자재료학회논문지
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• 제14권5호
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• pp.405-409
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• 2001

This paper describes fabrication and characteristics of metal thin-film pressure sensor for working at high temperature. The proposed pressure consists of a chrom thin-film, patterned on a Wheat stone bridge configuration, sputter-deposited onto thermally oxidized Si membranes with an aluminium interconnection layer. The fabricated pressure sensor presents a low temperature coefficient of resistance, high-sensitivity, low non-linearity and excellent temperature stability. The sensitivity is 1.097∼1.21mV/V$.$kgf/$\textrm{cm}^2$ in the temperature range of 25∼200$^{\circ}C$ and the maximum non-linearity is 0.43%FS.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집
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• pp.181-184
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• 2002

This paper describes fabrication and characteristics of ceramic pressure sensor for working at high temperature. The proposed pressure sensor consists of a Ta-N thin-film, patterned on a Wheatstone bridge configuration, sputter deposited onto thermally oxidized Si membranes with an aluminium interconnection layer. The fabricated pressure sensor presents a low temperature coefficient of resistance, high sensitivity, low non-linearity and excellent temperature stability The sensitivity is 1.097∼1.21 mV/V$.$kgf/$\textrm{cm}^2$ in the temperature range of 25∼200$^{\circ}C$ and the maximum non-linearity is 0.43 %FS.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 추계학술대회 논문집 Vol.15
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• pp.456-459
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• 2002

This paper describes fabrication and characteristics of ceramic pressure sensor for working at high temperature. The proposed pressure sensor consists of a Ta-N thin-film, patterned on a Wheatstone bridge configuration, sputter deposited onto thermally oxidized Si membranes with an aluminium interconnection layer. The fabricated pressure sensor presents a low temperature coefficient of resistance, high sensitivity, low non-linearity and excellent temperature stability. The sensitivity is 1.097~1.21mV/$V{\cdot}kgf/cm^2$ in the temperature range of $25{\sim}200^{\circ}C$ and the maximum non-linearity is 0.43 %FS.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제53권8호
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• pp.500-508
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• 2004

This paper presents a new sensorless vector control system for high performance induction motor drives fed by a matrix converter with non-linearity compensation and disturbance observer. The nonlinear voltage distortion that is caused by commutation delay and on-state voltage drop in switching device is corrected by a new matrix converter modeling. The lumped disturbances such as parameter variation and load disturbance of the system are estimated by the radial basis function network (RBFN). An adaptive observer is also employed to bring better responses at the low speed operation. Experimental results are shown to illustrate the performance of the proposed system.

• 한국근적외분광분석학회:학술대회논문집
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• 한국근적외분광분석학회 2001년도 NIR-2001
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• pp.1011-1011
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• 2001

In general, NIR reflectance spectra (whether recorded using log(1/R) or the Kubelka-Munk function) are not linear functions of the concentration of the absorbers which we are measuring. There are several causes for this non-linearity, the most commonly cited one being front surface reflection. However, non-linearity also arises from the effects of particle size, sample thickness, void fraction, and experimental arrangement. In this talk, we will attempt to isolate the effects of the various causes, and show the effects of each, using both theoretical calculations and actual data. The listener should then be able to assess where we stand in our quest to produce “linear” data through pre-processing and/or alternate collection schemes.