• 제목/요약/키워드: Elliptical hole

검색결과 41건 처리시간 0.019초

Dispersion and Nonlinear Properties of Elliptical Air Hole Photonic Crystal Fiber

  • Rao, MP Srinivasa;Singh, Vivek
    • Current Optics and Photonics
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    • 제2권6호
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    • pp.525-531
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    • 2018
  • The effect of eccentricity on dispersion and nonlinear properties of a photonic crystal fiber having elliptical air holes is investigated using a fully vectorial effective index method. It is found that the effective refractive index increases with increase of eccentricity. The dependence of dispersion and nonlinear properties of the PCF on the eccentricity of the air hole is investigated. It is revealed that eccentricity of the air hole affects the zero dispersion wavelength. Further, the nonlinear properties such as mode field area, nonlinear coefficient and self phase modulation of the Photonic crystal fibers are analyzed. The mode field area increases and the nonlinear coefficient decreases with increase in eccentricity. The variation of the self phase modulation with elliptical air hole is also discussed.

평판에서 타원공의 형상에 따른 피로도지수 해석 (The Analysis of Fatigue Quality Index for Shape of Elliptical Hole in Plate)

  • 송준혁;노홍길;강희용;양성모
    • 한국공작기계학회:학술대회논문집
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    • 한국공작기계학회 2003년도 춘계학술대회 논문집
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    • pp.130-136
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    • 2003
  • A FQI(fatigue quality index) analysis using the concept of SF(severity factor) is performed to various shape of elliptical hole. FQI is fatigue quality index to estimate the dynamic SF from static SF by finite element analysis. Since the SF is affected by the location of cutout in plate and radius ratio, static SF is analyzed with finite element method and forms the equation of FQI for predicting a dynamic SF. To examine the validity, dynamic SF is measured by photoelastics and thermalelastics for an epoxy resin plate with various elliptical holes under dynamic load.

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타원형 공동을 갖는 새로운 고복굴절 광섬유의 설계 (Novel design of higly-birefringet fiber with elliptical hollow)

  • 황인각;이용희;오경환
    • 한국광학회:학술대회논문집
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    • 한국광학회 2004년도 제15회 정기총회 및 동계학술발표회
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    • pp.370-371
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    • 2004
  • We propose and analyze a novel high-birefringence fiber incorporating an elliptical air hole in the core. Compared to solid elliptical core fibers, several times higher birefringence is achieved with a sub-wavelength-sized hole.

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IRON LINE PROFILES FROM RELATIVISTIC ELLIPTICAL ACCRETION DISKS

  • CHANG HEON-YOUNG;CHOI CHUL-SUNG
    • 천문학회지
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    • 제35권3호
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    • pp.123-130
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    • 2002
  • An elliptical accretion disk may be formed by tidally disrupted debris of a flying-by star in an active galactic nucleus (AGN) or by tidal perturbation due to a companion in a binary black hole system. We investigate the iron K$\alpha$ line profiles expecting from a geometrically thin, relativistic, elliptical disk in terms of model parameters, and find that a broad and skewed line profile can be reproduced well. Its shape is variable to the model parameters, such as, the emissivity power-law index, the ellipticity of the disk, and the major axis orientation of the elliptical accretion disk. We suggest that our results may be useful to search for such an elliptical disk and consequently the tidal disruption event.

다공평판의 형상최적화에 관한 연구 (A Study on the Shape Optimal Design of Perforated Plate)

  • 김형준;권영석;박정호;안찬우;김현수
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 1997년도 추계학술대회 논문집
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    • pp.731-734
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    • 1997
  • In this study, a shape optimization is performed for circular and elliptical holes to reduce weight of a plate. It is accomplished in reference to the results of topology optimization of the square plate with circular hole. From the results. it is concluded that the stress values of shape optimization of them are satisfied with 100MPa of constraint condition.

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디젤엔진에서 노즐 홀 형상효과의 실험적 연구 (Experimental Study of the Effects of Nozzle Hole Geometry for di Diesel Engine)

  • 구건우;이영진;김인수;이충원
    • 한국분무공학회지
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    • 제12권3호
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    • pp.154-159
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    • 2007
  • Spray tip penetration and spray angle for one main injection were measured at the atmospheric condition with the fuel injection pressure of 270 bar and 540 bar. It investigates an effect of different nozzle hole geometry of conventional cylindrical one and those of elliptical ones. Injection period represented by injector pulse drive was fixed at 1ms. From the result of this study, it is shown that spray tip penetration becomes shorter and spray angle becomes wider with the elliptical nozzle hole geometry due to fast break-up of a fuel liquid column.

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복소퍼텐셜을 이용한 타원공 또는 균열을 가진 복합재 평판 응력해석 (Stress Analysis of Composite Plate with an Elliptical Hole or a Crack Using Complex Potentials)

  • 권정호;황경정
    • Composites Research
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    • 제20권5호
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    • pp.56-63
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    • 2007
  • 복소퍼텐셜을 이용하여 타원공 또는 균열을 내재한 복합재 적층판구조 해석법을 고찰하였다. 복합재 적층판은 충격에 취약하며 이러한 충격손상은 타원공이나 균열형태의 노치로 모델화된 바 있다. 이와 같이 컷아웃부를 내재한 복잡한 형태의 복합재 적층판 해석에 유한요소해석법이 널리 사용되고 있으나 피로하중 하에서의 손상허용성 평가와 같이 손상진전에 따라 반복적으로 유한요소모델링을 수정하여 해석을 수행하여야 하는 경우 매우 번거로운 작업이 요구된다. 이러한 관점에서 복소퍼텐셜을 이용한 해석적 기법은 매우 간편하고 사용하기 손쉬운 기법이라고 할 수 있다. 이러한 해석법에 의한 계산결과를 유한요소해석 결과와 비교 분석함으로써 계산과정의 유효성과 용이성을 검증하였다.

Highly Birefringent Slotted-porous-core Photonic Crystal Fiber with Elliptical-hole Cladding for Terahertz Applications

  • Lee, Yong Soo;Kim, Soeun;Oh, Kyunghwan
    • Current Optics and Photonics
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    • 제6권2호
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    • pp.129-136
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    • 2022
  • We propose a photonic crystal fiber (PCF) with a slotted porous core and elliptical-hole cladding, for high birefringence in the terahertz regime. Asymmetry in the guided mode is obtained mainly by using arrays of elliptical air holes in the TOPAS® polymer cladding. We investigate the tradeoff between several structural parameters and find optimized values that can have a high birefringence while satisfying the single-mode condition. The optical properties in the terahertz regime are thoroughly analyzed in numerical simulations, using a full-vector finite-element method with the perfectly-matched-layer condition. In an optimal design, the proposed photonic crystal fiber shows a high birefringence of 8.80 × 10-2 and an effective material loss of 0.07 cm-1 at a frequency of 1 THz, satisfying the single-mode-guidance condition at the same time. The proposed PCF would be useful for various polarization-management applications in the terahertz range.

가중함수법에 의한 기계적 체결홀에 존재하는 타원호형 관통균열의 음력확대계수 해석 ( I ) - 가중함수법의 전개 - (Stress Intensity Factor Analysis of Elliptical Arc Through Cracks at Mechanical Fastener Holes by Weight Function Method ( I ) - Development of Weight Function Method -)

  • 허성필;양원호;현철승
    • 대한기계학회논문집A
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    • 제25권10호
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    • pp.1659-1670
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    • 2001
  • It has been reported that cracks at mechanical fastener holes usually nucleate as elliptical corner cracks at the faying surface of the mechanical joints and grow as elliptical arc through cracks after penetrating the opposite surface. The weight function method is an efficient technique to calculate the stress intensity factors fur elliptical cracks using uncracked stress field. In this study the weight function method for three dimensional mixed-mode problem applied to elliptical comer cracks Is modified for elliptical arc through cracks and the stress intensity factors at two surface points of elliptical arc through cracks at mechanical fastener holes are analyzed by the weight function method. This study consists of two parts and in part I , the weight function method for elliptical arc through cracks is developed and verified.

기계적 체결홀에 존재하는 타원호형 관통균열에 대한 가중함수법의 적용 (Application of Weight Function Method to Elliptical Arc Through Cracks at Mechanical Fastener Holes)

  • 허성필;양원호;정기현;현철승
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2001년도 추계학술대회논문집A
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    • pp.304-310
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    • 2001
  • Cracks at mechanical fastener holes usually nucleate as elliptical comer cracks at the faying surface of the mechanical joints and grow as elliptical arc through cracks after penetrating the opposite surface. In this study mode I, II and III stress intensity factors at two surface points of elliptical arc through cracks at mechanical fastener holes are analyzed by applying weight function method. The weight function method for two dimensional mixed-mode problem is extended to three dimensional one and it is verified.

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