• Tribology and Lubricants
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• 제7권2호
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• pp.13-21
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• 1991

선박은 사람이나 화물을 수상(水上) 운송수단의 목적으로 오랜 옛날부터 사용하여 왔으며, 금세기에 이르러서는 오랜 옛날부터 사용하여 왔으며, 금세기에 이르러서는 인류문화의 급속한 발전에 따라 주변생활이 가속화(Speed화), 합리화되어 문명의 혜택을 보다 많이 누리게 된 반면에, 국제간에 파생되는 여러가지 교환현상을 바탕으로 지구는 하나의 촌(村)으로 되어 유통경제를 지배하고 이용하는 운송수단으로 발전되어 왔다. 물질문명이 급속히 발전하는 작금, 선용추진 주 기관의 동향을 살펴보면, 1981년 세계에서 건조한 2000톤급 이상의 선박은 940여척으로 이중 13척이 증기 Turbine. 추진(推進), 나머지는 미끄럼 저속 디이젤 또는 중고속 디이젤 추진으로 되어있다. 이와 병행하여 선박에 쓰여지고 있는 각종 윤활제는 주기관으로서 디이젤 engine, Trubine engine, 가솔린 engine, 석유, engine, 선외기, 왕복동 증기기관, Journal계열로서 역전기, 추력베어링, 중간 베어링, 프로펠러베어링, 일반상선으 보조기계로서 발전기, 공기압축기, Boiler, 각종 Pump, 각종 Motor, 냉동기, 조타장치, Side Thrust, 갑판기계, 환기용 송풍기 및 통풍통, Oil 청정기, 수밀로(水蜜爐), 소화설비, 주기 개방용 천정 크레인, elevator, 어선으로서의 주 기관, 보조기기 등에 쓰여지고 있으며 이밖에 수중날개선 등에도 적용되는 등 실로 다양다종한 윤활제가 요구되고 있음에, 본 논고에서는 제목 건을 중심으로 한 선박과 윤활의 중요 Point만을 간추려 기술하고져 한다.

• Journal of Electrical Engineering and Technology
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• 제10권5호
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• pp.2052-2056
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• 2015

This Paper analyzes the characteristics of the WRSM in high-speed operation range. To verify the control characteritics of various WRSM models, the relative position of the central point of current limit circle and voltage limit ellipse is defined as M value and 3 models according to M_max value are designed through inductance change. Through the designed models, the current control method of 3-variables control for maximum power especially in high-speed operation range is presented.

• 한국연소학회지
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• 제4권2호
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• pp.43-50
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• 1999

Liquefied petroleum gas (LPG) has been used as motor fuel due to its low emissions and low cost. The fuel feeding system has been improved with stringent requirement for exhaust emissions. LPG carburetion system was first introduced, then the system has been changed to a precisely controlled gas injection system, but this gas feeding system has a limitation on improving power output. In order to improve an engine performance, a multi-point port injection system was introduced recently, and a liquid direct injection system into a cylinder was suggested as a next generation system to maximize a fuel economy as well as a power. This study addresses the analysis of the LPG spray from diesel injectors. The spray images are visualized and compared with diesel sprays in a wide injection pressure range. The photographs show much wider dispersion of LPG sprays.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 1993년도 Proceedings of International Conference for Agricultural Machinery and Process Engineering
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• pp.761-767
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• 1993

A precision planting system using computer controlled technology for mulching cultivation was developed and tested . The system consisting of a micro-computer, several optical fiber sensors and control actuators realized the mechanization of the precision planting operation. The film hole positions, existences of a seed on shutter were detected and the planting speed was measured. The shutter opening mechanism and a seed metering device driven by a stepping motor were controlled, automatically . The planting timing of the shutter opening mechanism were analyzed from a video camera motion analysis, theoretically. The results showed a sufficient accuracy of a seed planted into the center a film hole with a variety of planting speeded. The gravity point positions in film hole of seeds planted by the system just were within the area of +-5mm of the hole center when the hole diameter was 40mm.

• 한국연소학회:학술대회논문집
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• 한국연소학회 1999년도 제19회 KOSCO SYMPOSIUM 논문집
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• pp.21-26
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• 1999

Liquefied petroleum gas(LPG) has been used as motor fuel due to its low emissions and low cost. The fuel feeding system has been improved with stringent requirement for exhaust emissions. LPG carburation system was firstly introduced, then the system changed into a gas injection system controlled precisely, but those gas feeding system has a limitation on improving power output. In order to improve an engine performance, a multi-point port injection system was introduced recently, and a liquid direct injection system into a cylinder was suggested as a next generation system to maximize a fuel economy as well as a power. This study addresses the analysis of the LPG spray from diesel injectors. The spray images are visualized and compared with diesel sprays in a wide injection pressure range. The photographs show much wider dispersion of LPG sprays.

• 전기의세계
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• 제26권3호
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• pp.76-83
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• 1977

The choice of control method and circuit must be decided after a broad inspection with the characteristics of load and control elements as well as that of electric and mechanical nature. In the present study, Pulse width modulated(PWM) SCR chopper was chosen and for the electric commutation, Jones' forced method was taken bacause of its having enough reverse bias energy. Objectives of experimentation by this system are; 1) the condition of SCR as a gate trigger pulse. 2) the observation of phenomena at the time of forced commutation 3) the experimentation on characteristics of speed control by PWM chopper. Above experimentation shows good characteristics, however, in the limit of narrow gap between the ON and OFF pulses, a complete control was not possible. So, that must be the point to be studied further alone with the harmonics influence.

• 대한전기학회논문지
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• 제36권6호
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• pp.430-436
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• 1987

A Detection filter that can be used for the Detection and Isolation of process faults is proposed by the use of fault vector modelling, and is applied to DC Motor fault detection. The proposed detection filter is a new one in a view point that its outputs are the estimates of fault variables(or linear combination of them) while all the existing filters estimate the state of process. By this properties, the process fault detection systems with this filter can be constructed in very simple structure. Besides the simplicity of structure and design procedure, the filter has an useful feature that various types of fault can be estimated via the filter by choosing appropriate fault models.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 1998년도 제11회 학술강연회논문집
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• pp.30-30
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• 1998

Solid rocket motor case의 internal insulator로 미가류 형태의 내열재에 적당하게 tacky성과 삭막 특성을 고려한 조성을 개발하여 시스템에 성공적으로 적용하였다. 개발된 내열재의 주요 조성으로는 base polymer로 EPDM과 CR을 80/20으로 blend하여 적용했으며, 삭막 특성 향상을 위해 아라미드 섬유인 Kevlar 29를 5 phrs, Hydrated silica인 Zeosil 155를 30phrs 적용하였다. 이와 같은 조성으로 제작된 내열재는 삭마시험, 인장시험, 열특성시험 등 각종 특성시험을 수행하여 시스템에 적용하기 위한 성능을 확인하고 공정에 적용하였다. ST-8 표준 모타에 적용하여 삭막시험한 결과 삭마율 0.21mm/sec를 얻었고, 추진기관 사용 온도인 -4$0^{\circ}C$-6$0^{\circ}C$ 온도 범위에서 기계적성질 값을 측정하여 성능 저하가 없는 안정된 값을 얻었으며, DSC로 Tg point 측정 결과 -55$^{\circ}C$로 나타나 저온특성이 우수한 EPDM 내열재 특성을 확인할 수 있었다.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제5권1호
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• pp.69-75
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• 2005

This paper is concerned with the design of a predictive PID controller, which has similar features to the model-based predictive controller. A PID type control structure is defined which includes prediction of the outputs and the recalculation of new set points using the future set point data. The optimal values of the PID gains are pre-calculated using the values of gains calculated from an unconstrained generalized predictive control algorithm. Simulation studies demonstrate the performance of the proposed controller and the results are compared with generalized predictive controller and the results are compared with generalized predictive control solutions.

• 전력전자학회논문지
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• 제5권5호
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• pp.467-474
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• 2000

본 논문에서는 배터리를 사용하는 유틸리티 차량용 컨트롤러 개발과 태양광 발전을 병행하여 차량의 운행시간을 보완하였다. 유틸리티 차량용 컨트롤러는 다른 컨트롤러와 호환성을 유지하고 저가격, 고성능을 위해 마이크로 프로세서를 이용하여 속도센서와 전류센서를 사용하지 않고 타여자 직류 전동기를 제어하였다. 태양광발전을 위해 DC-DC 컨버터를 이용하여 태양전지의 최대 전력점 추종 제어(MPPT)와 출력전류를 제어하여 태양전지와 배터리를 병렬운전하였다. 시스템의 타당성을 모의실험과 시제품의 실험을 통하여 검증하였다.