• 제목/요약/키워드: Performance conversion

검색결과 2,886건 처리시간 0.029초

3상 PWM Converter를 위한 정지 좌표계법 Analog 제어기 설계 및 시뮬레이션 (Design and Simulation of analog controller for 3 Phase PWM Converter Based on Stationary Reference Frame)

  • 이영국;노철원;최종률
    • 전력전자학회:학술대회논문집
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    • 전력전자학회 1997년도 전력전자학술대회 논문집
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    • pp.14-20
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    • 1997
  • Due to several advantages of Pulse Width Modulated(PWM) Converter, such as unity power factor with low-harmonics and energy regeneration, PWM converter has been widely used in industrial application. In every application of energy conversion equipment, the design and implementation must be carried out considering performance and cost. High quality with low cost is the best choice for energy conversion equipment. High dc link voltage can reduce inverter and motor side losses and system dimension compare to low dc link voltage. Analog controller can make PWM converter cheaper without considerable degradation of the performance than digital controller. This paper shows the simplified analog controller-for 600V dc link voltage using stationary reference frame control and the simulation results.

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석탄-물 혼합연료(CWM)의 분무 특성 (Atomization Characteristics of Coal-Water Mixture Fuel)

  • 노남선;신대현;김광호
    • 에너지공학
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    • 제3권2호
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    • pp.130-150
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    • 1994
  • Coal-water mixture(CWM) fuel has attracted much attention as a substitute fuel for oil by which high economics and short-term commercialization might be realized in comparison with other coal conversion technologies. There are many factors that affect the CWM combustibility, such as the physical properties of CWM, the performance of atomizer and burner, operating conditions, capacity and load of the boiler, etc. Particularly, atomization quality is extremely critical to achieving acceptable carbon conversion efficiency of CWM fuel and maintaining the flame stability, because the coal particles in the CWM droplets burn as agglomerates. This paper presents the R&D results about the CWM atomization characteristics, including the significance of CWM atomization the R&D results about the CWM atomization characteristics, including the significance of CWM atomization quality, the atomization and combustion mechanism, the type of CWM atomizer, size and size distribution of CWM droplets and some factors that influence the atomization performance.

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수치해석을 통한 Spiral 형상 화학 반응기의 열전달 특성 (Heat Transfer Characteristic of the Spiral Type Solar Chemical Reactor)

  • 정영국;이진규;이주한;서태범
    • 설비공학논문집
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    • 제22권1호
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    • pp.40-48
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    • 2010
  • The purpose of the research is to develop the high performance solar chemical reactor for producing hydrogen using steam reforming reaction of methane. A specific shape chemical reactor is suggested : spiral type reactor. The reactor is installed on the dish-type solar thermal system of Inha University. The temperatures, $CH_4$ conversion rates, and Hz proportion are measured. At specific condition, $CH_4$ conversion rates of the spiral type reactor are about 91%, and Hz proportion are about 66%. The spiral type reactor gives reasonably good performance without any problems caused by highly concentrated solar radiation.

배치형 내부 사이클론식 순환유동층 연소로내 2차 공기 주입에 의한 슬러지 소각 유해 배가스 저감효과 (Effect of Secondary Air Injection on Emission from Sludge Incineration in a Batch-type Internally Cycloned Circulating Fluidized Bed Combustor)

  • 장석돈;신동훈;황정호
    • 한국연소학회지
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    • 제7권3호
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    • pp.16-22
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    • 2002
  • Combustion performance of an internally cycloned circulating fluidized bed for paper sludge was discussed through a series of batch type experiments. Operation parameters such as water content, feeding mass of sludge and secondary air injection rate were varied to find out the effect on the combustion performance, which was examined with carbon conversion rate and pollutant emission such as CO and NOx. A conventional solid fuel reaction was observed in the experiments of varying water content and feeding mass of the sludge, which is characterized with kinetic limited reaction zone, diffusion limited reaction zone and transition zone. Secondary air injection with swirl enhances the mixing of the gas phase as well as the solid phase, and improves combustion efficiency accompanied with higher carbon conversion rate and lower pollutant emission rate.

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DDS를 이용한 BCPFSK모뎀 설계 및 성능 평가에 관한 연구 (A Study on Design and Performance Evaluation of the BCPFSK Modem Using the DDS)

  • 김경복;최정수;조형래
    • 한국정보통신학회:학술대회논문집
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    • 한국해양정보통신학회 2000년도 추계종합학술대회
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    • pp.166-171
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    • 2000
  • 현대 무선 통신에서는 제한된 주파수 자원을 효율적으로 사용하기 위해 스펙트럼 효율성이 매우 중요한 문제로 여겨지고 있다. 또한 시스템구조 측면에서는 저 가격, 저 전력 및 초경량에 목표를 두고 제작되고 있다. 본 논문에서는 직접 디지털 주파수합성기(DDS ; Direct Digital Synthesize.)를 이용하여 스펙트럼 효율이 우수한 BCPFSK(Binary Continuous Phase Frequency Shift Keying)를 직접 변조하였으며, 시스템 구조로는 직접 변환(Direct Conversion) 구조를 적용하여, 433 MHz대의 BCPFSK 출력을 갖는 송 ·수신기를 설계하고 성능을 평가하였다.

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귀금속 함량에 따른 디젤산화촉매의 이산화질소 배출 특성 (Emission Characteristics of NO2 in Diesel Oxidation Catalyst according to the Content of Precious Metal)

  • 김훈명;박용성;이광구
    • 한국연소학회:학술대회논문집
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    • 한국연소학회 2012년도 제45회 KOSCO SYMPOSIUM 초록집
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    • pp.37-38
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    • 2012
  • Two catalyst systems with different content of precious metal coated on DOC are carefully tested in a diesel engine to investigate the emission characteristics of $NO_2$. Three types of experiment methods ($NO_2$ conversion test, ETC mode test, and BPT test) are applied to compare the performance of the two catalyst systems. All the experimental results consistently indicate that it is possible to satisfy $NO_x$ regulation by properly lowering the content of precious metal without the loss of PM removal performance.

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Ku대역 전파고도계 체계점검장비 개발 (A Development of Missile System Test Equipment for Ku-Band Radar Altimeter)

  • 김태훈;정진섭
    • 한국군사과학기술학회지
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    • 제18권6호
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    • pp.808-815
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    • 2015
  • For performance improving of C-band radar altimeter used in a missile system, Ku-band radar altimeter is developed. To utilize the time delay devices which are used in testing C-band radar altimeter, we proposed C-band and Ku-band frequency conversion method and implemented it as a part of missile system test equipment. In this paper we present design contents, development results and test application results of radar altimeter test equipments.

광 버스트 스위치를 위한 새로운 충돌 해결 알고리즘 (New Contention Resolution algorithm for Optical Burst Switch)

  • 정명순;엄진섭
    • 한국통신학회논문지
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    • 제29권12A호
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    • pp.1285-1290
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    • 2004
  • 본 논문에서는 광 버스트 네트워크 내의 버스트 충돌을 해결하기 위한 새로운 알고리즘을 제안하였다. 제안된 알고리즘은 파장 변환(conversion), 경로 변경(deflection), 분리(segmentation), 광섬유 버퍼링을 흔합하여 광 스위치에 적용한 것이다. 제안된 충돌 해결 알고리즘의 성능은 ns(network simulator)-2를 이용하여 분석하였다. 시뮬레이션에 사용한 네트워크 토폴로지는 한국의 기간망을 가정하였고 이를 기반으로 다양한 네트워크 트래픽 조건에서 성능 지표(버림 확률, 전파 지연)의 개선을 보였다.

Ni-P Coated Sn Powders as Anode for Lithium Secondary Batteries

  • Jo, Yong-Nam;Im, Dong-Min;Kim, Jae-Jung;Oh, Seung-M.
    • 전기화학회지
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    • 제10권2호
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    • pp.88-93
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    • 2007
  • Nano-sized Sn particles were coated with Ni-P layer using an electroless deposition method and their anodic performance was tested for lithium secondary batteries. Uniform coating layers were obtained, of which the thickness was controlled by varying the $Ni^{2+}$ concentration in the plating bath. It was found that the Ni-P layer plays two important roles in improving the anodic performance of Sn powder electrode. First, it prevents the inter-particle aggregation between Sn particles during the charge/discharge process. Second, it provides an electrical conduction pathway to the Sn particles, which allows an electrode fabrication without an addition of conductive carbon. A pseudo-optimized sample showed a good cyclability and high capacity ($>400mAh\;g^{-1}$) even without conductive carbon loading.

Correlation Between the Optical Performance of the Reflective Polarizer and the Structure of LCD Backlight

  • Yu, Mi-Yeon;Lee, Byung-Woo;Lee, Jeong-Ho;Ko, Jae-Hyeon
    • Journal of the Optical Society of Korea
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    • 제13권2호
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    • pp.256-260
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    • 2009
  • The optical performance of the reflective polarizer was investigated over three kinds of direct-lit backlights and/or different configurations of the optical sheets. The optical gain factor achieved by using the reflective polarizer increased as the diffuse nature of the optical sheet was enhanced, because of the more efficient polarization conversion. In addition, the gain factor decreased substantially in flat-lamp backlights compared to tubular-lamp backlights, which was ascribed to the high loss factor during the polarization recycling process due to the complex structure and large area of flat lamps. All these results suggested that reducing the loss factor of the backlight is very important for efficient polarization conversion and thus high optical gain of the reflective polarizer.