• 제목/요약/키워드: Abrupt

검색결과 1,256건 처리시간 0.026초

접합구조에 따른 AIGaAs/GaAs HBT의 DC 특성에 관한 연구 (DC Characteristics of AIGaAs/GaAs HBTs with different Emitter/Base junction structures)

  • 김광식;유영한;안형근;한득영
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2000년도 하계학술대회 논문집
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    • pp.67-70
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    • 2000
  • In this paper, all SCR recombination currents including setback and graded layer's recombination currents are analytically introduced for the first time. Different emitter-base structures are tested to prove the validity of the model. In 1995, the analytical equations of electric field, electrostatic potential, and junction capacitance for abrupt and linearly graded heterojunctions with or without a setback layer was derived. But setback layer and linearly graded layer's recombination current was considered numerically. In this paper, recombination current model included setback layer and graded layer is proposed. New recombination current model also includes abrupt heterojunction's recombination current model. In this paper, new recombination current model analytically explains effects of setback layer and graded layer.

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퍼지논리를 이용한 차량용 공조제어기 개발에 관한 연구 (Development of Automobile Air Conditioner Controller based on the Fuzzy Logic)

  • 이용중;이운근;이양범
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1996년도 하계학술대회 논문집 B
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    • pp.1323-1326
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    • 1996
  • This paper describes an air conditioner control method using a fuzzy control theory. The fuzzy control method was implemented with Philips 80C552 one chip microcomputer and tested in an actual vehicle. Experiments showed that proposed control method is superior to the conventional PID control method especially in the environments with abrupt disturbance and parameter variation of the control system. Fuzzy-Based control method was proved to maintain a stable and improved temperature control in an abrupt environmental changes.

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A comparative study of several nickel-titanium instruments on canal shaping ability in the simulated canal with abrupt curvature

  • Lim, Jung-Jang;Hwang, In-Nam;Oh, Won-Mann
    • 대한치과보존학회:학술대회논문집
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    • 대한치과보존학회 2003년도 제120회 추계학술대회 제 5차 한ㆍ일 치과보존학회 공동학술대회
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    • pp.595-595
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    • 2003
  • I. Objectives This study was done to evaluate which type of Ni-Ti instrument be able to perform canal shape well in the simulated canal with abrupt curvature near it's apex. II. Materials and Methods A total of 96 simulated root canals were made in epoxy resin(EPOXICURETM, BUEHLER, USA), #15 finger spreader (MANI, Japan) were used as root canal templates. The simulated root canal were made with radius of curvature of 1.5 mm, 3.0 mm, 4.0 mm, 6.0 mm respectively, and angle of curvature of all simulate camals was 90 degree.(omitted)

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급진적/점진적 장면 전환 검출 기법 (Abrupt/Gradual Scene Change Detection Method)

  • 백정욱;신성윤;이양원
    • 한국정보통신학회:학술대회논문집
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    • 한국해양정보통신학회 2009년도 추계학술대회
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    • pp.179-180
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    • 2009
  • 기존의 장면전환 검출의 문제점들을 줄이고 복잡하고 다양한 실세계의 영상변화를 가장 일반적이고 표준화된 방법으로 분석하고 분할하며 표현할 수 있는 기법을 제안하고자 한다. 본 논문에서는 새로운 로컬 컬러 ${\lambda}^2$-테스트를 제한하는데 이는 기존의 ${\lambda}^2$-테스트와 로컬 컬러 히스토그램을 결합한 방법이다. 이 방법은 급진적 장면전환과 점진적 장면전환을 모두 검출할 수 있는 강건한 방법을 제시하여 기존에 장면전환 검출 방법이 안고 있던 문제를 해결하였다.

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고속제트 플럼에서의 기저압력 특성 (Characteristics of the Base Pressure in High-Speed Jet Plume)

  • ;김희동
    • 한국추진공학회:학술대회논문집
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    • 한국추진공학회 2011년도 제36회 춘계학술대회논문집
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    • pp.193-195
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    • 2011
  • An abrupt increase of duct cross-section is frequently encountered in pressure reducing devices, valves of internal combustion engines and in gas pipelines. Supersonic flow in a rectangular duct passing an abrupt increase of cross-section is studied numerically. The behavior of base pressure of the dead-air region at sudden enlargement of the duct is clarified. This investigation concerns the determination of the base pressure, which is independent of the size of the enlarged part. Several flow patterns are identified with different enlargements according to the ratio between the downstream ambient pressure and the upstream reservoir pressure. Base pressure and the resulting shock-structure are highly depending on the size of duct enlargement. For a given duct, base pressure tends to minimum for a particular pressure ratio. In addition, the locations of secondary separation and reattachment points of the jet plume are found with respect to different duct enlargements.

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Displacements of the flexible ring for an electromechanical integrated harmonic piezodrive system

  • Xu, Lizhong;Li, Huaiyong;Li, Chong
    • Structural Engineering and Mechanics
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    • 제60권6호
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    • pp.1079-1092
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    • 2016
  • In this paper, an electromechanical integrated harmonic piezodrive system is proposed. The operating principle of the drive system is introduced. The equation of the relationship between the displacements of the flexible ring and the rotating angle of the rotor is deduced. Using the equation, the displacements of the flexible ring for the drive system and their changes along with the system parameters are investigated. The results show that the displacements of the flexible ring changes periodically along with the rotation of the vibrator; there are abrupt changes in the displacements of the flexible ring at some points where there are abrupt changes in the number of the mesh teeth pair; the length of the flexible ring, the excitation voltage, and the speed ratio have obvious effects on the displacements of the flexible ring. The results are useful for the design of the drive system. ;

Abrupt Bulla Formation by Visceral Pleural Detachment after Pulmonary Lobectomy: A Case Report

  • Byeong A Yoo;Seungmo Yoo;Jae Kwang Yun;Sehoon Choi
    • Journal of Chest Surgery
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    • 제56권3호
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    • pp.216-219
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    • 2023
  • Pulmonary bullae usually grow slowly and have thin walls. However, we have observed 2 cases of abrupt bulla formation immediately after lobectomy and during surgery. The pathologic findings of what can be called visceral pleural detachment are quite distinctive: these bullae had a broad base connected to the lung, and their walls were thick, including the full extent of visceral pleural and peripheral alveolar tissues, which suggests that the visceral pleura were detached from the distal alveoli. High transpleural pressure might be the key factor in the pathogenesis of this type of bulla, unlike previously known types of bullous lung disease.

Dietary fat preference and effects on performance of piglets at weaning

  • Weng, Ruey-Chee
    • Asian-Australasian Journal of Animal Sciences
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    • 제30권6호
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    • pp.834-842
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    • 2017
  • Objective: An experiment was to evaluate the interplay of dietary lipid sources and feeding regime in the transition from sow milk to solid food of abruptly weaned piglets. Methods: Soon after weaning, 144 piglets were selected and were trained over a 15 day period to experience gradually reducing dietary fat content from 12% to 6% for lard (L), soybean oil (S), and coconut oil (C) and their feeding behavior and diet preference then tested in a behavior observation experiment. Another 324 weaned piglets were used in three consecutive feeding experiments to measure the effect of different dietary fats on performance and feed choice in the four weeks after abrupt weaning. The lipid sources were used as supplements in a 3% crude fat corn/soya basal diet, with 6% of each being included to form diets 9C, 9S, and 9L respectively, and their effects on performance measured. Combinations of these diets were then further compared in fixed blends or free choice selection experiments. Results: Piglets pre-trained to experience reducing lipid inclusion showed different subsequent preferences according to lipid source, with a preference for lard at 9%, soybean oil at 3%, and coconut oil at 6% inclusion rate (p<0.001). Following abrupt weaning, whilst after 4 weeks those fed 9C had the heaviest body weights (18.13 kg, p = 0.006). Piglets fed a fixed 1:1 blend of 9C+9S had a poorer feed conversion ratio (FCR = 1.80) than those fed a blend of 9C+9L (FCR = 1.4). The 9C and 9L combination groups showed better performance in both fixed blend and free choice feeding regimes. Conclusion: After abrupt weaning, they still have dependence on high oleic acid lipids as found in sow milk. A feeding regime offering free choice combination of lipids might give the possibility for piglets to cope better with the transition at weaning, but further research is needed.