• Title, Summary, Keyword: 클래딩

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Acoustic Emission Applied to Real-time Monitoring of Submerged Arc Cladding Quality (서브머지드 아크 클래딩의 실시간 품질감시를 위한 음향방출 진단 기술)

  • ;;Shan-Ping Lu
    • Proceedings of the KWS Conference
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    • pp.318-321
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    • 2001
  • 클래딩은 주요 산업분야에 내마모성, 내부식성의 향상을 위해 사용되고 있다. 그러나 클래딩 공정에서는 모재와 클래딩 재료의 물리적, 화학적 특성의 차이와 여러 가지 공정 변수의 영향으로 제품의 사용에 치명적인 손상을 줄 수 있는 균열, 슬래그 개재물, 기공등의 불연속이 발생하기 쉽다. 본 연구에서는 클래딩 시에 발생되는 불연속을 실시간으로 검출하는데 아주 우수한 검출능력을 갖고 있는 비파괴 검사 방법인 음향방출시험을 적용하고 검출된 신호에 대한 주파수 분석과 2차원 위치표정을 실시하여 균열, 기공 등의 불연속을 검출하였고 이를 주사전자현미경을 통하여 확인하였다. 음향방출법에 의해 클래딩부에서 발생하는 결함에 대한 실시간 평가가 가능함을 입증하였으며, 특히 다층 클래딩이나 넓은 면적의 클래딩시에 불연속을 가장 신속하게 감지할 수 있으므로 이를 생산공정에 활용한다면 클래딩 또는 용접부 품질감시를 위한 효과적인 방법이 될 것이다.

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Optical fiber connector using long-period fiber gratings imprinted in double cladding fiber (이중 클래딩 광섬유에 새겨진 장주기 격자를 이용한 광커넥터)

  • 김명진;엄태중;백운출;이병하;박태상
    • Proceedings of the Optical Society of Korea Conference
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    • pp.202-203
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    • 2003
  • 광통신 시스템에 필요한 여러 가지 광소자들과 광섬유간의 결합손실을 줄이고 결합거리를 향상시키기 위한 연구가 많이 이루어져 왔다. 광섬유의 클래딩 모드를 이용하여 정렬오차를 줄인 광커넥터에 대한 결과가 보고된 바 있다. 그러나, 장주기 광섬유격자를 통하여 여기된 광섬유의 클래딩 모드는 외부환경에 매우 민감하여 외부 접촉에 의한 손실과 공진 파장의 변화 등이 문제로 제시되었다. 본 연구에서는 코어와 통상의 클래딩 사이에 또 하나의 클래딩 층을 갖는 이중 클래딩 구조의 광섬유에 장주기 격자를 만들고, 장주기 격자에 의하여 여기된 여러 클래딩 모드 가운데 광섬유의 코어와 내부 클래딩 층으로만 주로 진행하는 첫 번째 클래딩 모드를 사용하는 광커넥터를 제안한다. (중략)

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Optical Characteristics of Two-dimensional Silicon Photonic Crystal Slab Structures with Air and Silica Cladding (공기 및 실리카 클래딩을 갖는 2차원 실리콘 광자 결정 슬랩 구조의 광학적 특성)

  • Lee, Yoon-Sik;Han, Jin-Kyu;Song, Bong-Shik
    • Korean Journal of Optics and Photonics
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    • v.20 no.4
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    • pp.211-216
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    • 2009
  • Much research into two-dimensional (2-D) photonic crystal (PC) structures has been conducted for realization of ultrasmall optical integrated circuits. A 2-D silicon (Si) PC slab structure with air cladding (n=1) is one of the representative structures in 2-D PCs. While air-clad Si PC slab structures have good optical characteristics, their suspension in air can lead to mechanical weakness, making integration with some optical devices difficult. In this paper, we propose improving the mechanical robustness of PC structure by developing a 2-D Si PC structure with symmetric silica cladding (n=1.44) and comparing its optical properties to that of the air-clad structure. First, we investigate the optical properties of a 2-D Si PC slab structure with air cladding by using a 3-D finite difference time domain method. We determined that a photonic bandgap of 330 nm and a non-leaky propagating bandwidth of 100 nm in the optical communication range are possible. Next, we investigate the optical properties of 2-D Si PC slab structures with silica cladding. Even though the refractive index of the silica cladding is higher than that of air, we developed a silica-clad structure with good optical properties: a photonic band gap of approximately 230 nm and a non-leaky propagating bandwidth of 90 nm, comparable to that of the air-clad PC structures.

The Study on Laser Cladding of Heat Resisting Steel Using EuTroLoy 16006 Powder(I) - Characteristics of 1 Pass Clad Layer with Process Parameters - (EuTroLoy 16006 분말을 이용한 내열강의 레이저 클래딩에 관한 연구(I) - 공정변수에 따른 1패스 클래드 층의 특성 -)

  • Kim, Jong Do;Lee, Eun Jin;Kim, Cheol Gyu
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.41 no.4
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    • pp.299-305
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    • 2017
  • Re-engineering is gaining attention due to severe environmental pollution and economic crisis. Although re-engineering in shipbuilding has been carried out steadily, technological advancements, domestic ship repair and maintenance industries are not as prevalent as shipbuilding industries. In order to solve this problems, laser cladding can significantly aid with technical development. Laser cladding produces an outstanding clad layer with minimal dilution and little porosity. In this study, prior to applying laser cladding to an exhaust valve face, the effects of various parameters that affect the characteristics of the 1 pass clad layer were investigated. When laser power was increased, the clad layer width became broader and the height was decreased. In addition, it was identified that the hardness of the clad layer was inversely proportional to the power, and the entire clad layer was diluted through an EDS chemical composition analysis.

The Effect of Microbending on Photonic Crystal Fiber (광자결정 광섬유의 마이크로벤eld 영향)

  • 문대승;김진채;엄주범;백운출;이병하
    • Proceedings of the Optical Society of Korea Conference
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    • pp.168-169
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    • 2002
  • 일반적인 광섬유가 실리카로 만들어진 클래딩과 이보다 약간 굴절률이 높은 코어로 구성되어 있는 것과는 달리 광자결정 광섬유(photonic crystal fiber 또는 다공성 광섬유(holey fiber))는 코아와 클래딩이 순수 실리카로 구성되어 있다 클래딩의 효과를 주기 위해 광섬유 축을 따라서 규칙적인 공기구멍 다발을 형성하여 준다. 광자결정 광섬유는 특이한 광학적 특성 때문에 최근에 활발히 연구되어 지고 있다. 공기구멍의 구조를 조절함으로써 넓은 파장 영역에서 단일 모드로 진행하고(1), 아주 큰 분산을 갖게 할 수 lT고, hem 반경을 조절 할 수 있으며, 특이한 분산 특성과 이의 조절이 가능하다. (중략)

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Fabrication of side-polished fiber using a polishing wheel and its applications (연마휠을 이용한 측면 연마 광섬유 제작과 그 응용)

  • 문정원;이준옥;황중호;정인수;윤대성;최종운;김광택
    • Proceedings of the Optical Society of Korea Conference
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    • pp.50-51
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    • 2002
  • 측면 연마된 광섬유 표면 위에 새로운 물질층을 형성시킨 후 광섬유 모드의 소산장(evanescent field) 결합을 유도하여 다양한 능동 및 수동 광섬유로 응용이 가능하다. 광섬유를 연마하기 위하여 쿼츠에 형성된 홈에 광섬유를 에폭시로 고정시키고 쿼츠와 함께 광섬유 클래딩을 연마하는 방법이 잘 알려져 있다. 이러한 방법은 측면 연마된 광섬유를 연마하는데 다소 긴 시간이 필요하다. 본 논문은 광섬의 클래딩을 연마휠로 제거하는 기법을 소개하고 연마된 광섬유의 클래딩 위에 금속이나 유전체층을 결합하여 기능성 광섬유 소자를 제작할 수 있음을 보인다. (중략)

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Study on Laser Cladding of Heat Resisting Steel Using EuTroLoy 16006 Powder(II) - Characteristics of Alloying Elements Distribution of Multi Pass Clad Layer - (EuTroLoy 16006 분말을 이용한 내열강의 레이저 클래딩에 관한 연구(II) - 멀티패스 클래드 층의 합금 성분 분포 특성 -)

  • Kim, Jong Do;Lee, Eun Jin;Kim, Cheol Gyu
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.41 no.4
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    • pp.307-312
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    • 2017
  • Laser cladding has some advantages compared to conventional cladding technologies such as arc welding and thermal spraying. Laser cladding produces a metallurgically well-bonded clad layer with a lower dilution ratio and few defects. Based on the characteristics of a 1-pass clad layer with many parameters, which were investigated in a previous report, it was found that it was essential to overlap a 1-pass clad layer when cladding a large area. In this study, the shape differences of multi-pass clad layers with various overlapping ratios were compared. Then, the alloying element distribution of cladding with a certain overlapping ratio was investigated using EDS and EPMA. As the overlapping ratio increased, the length of the clad decreased and its height increased. In addition, the height of the multi-pass cladding was higher than that of the 1-pass cladding under the same condition. The Fe content of the highly diluted first clad was found to be approximately 20 % in an element analysis. However in the area outside of the first clad, the Fe content was decreased to 10 % as a result of minimum dilution, and a uniform distribution of elements was found.

Polarization-independent temperature sensor using cladding layers of the overlay waveguide coupled with a side-polished fiber (측면 연마 광섬유와 결합된 상부 도파로의 클래딩을 이용한 편광 무의존 온도센서)

  • 손경락;김광택;송재원
    • Korean Journal of Optics and Photonics
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    • v.13 no.6
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    • pp.467-472
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    • 2002
  • In this paper, we propose a polarization-insensitive temperature sensor using a thermo-optic effect of the upper and (or) lower cladding of a planar waveguide in contact with a side-polished fiber. A microscope cover glass with thickness of a 170 ${\mu}{\textrm}{m}$ is adopted as an overlay waveguide because this waveguide opposes sudden temperature change and ensures polarization-insensitive responses. The measured polarization-dependence loss is less than 0.3 dB. The temperature can be detected as a result of the shift in coupling wavelength of the sensor. We investigate the shift in coupling wavelength as a function of the temperature variation with respect to the different thermo-optic coefficients of lower and upper claddings. We also show that the temperature sensitivity of the device can be easily controlled by the thermo-optic coefficients of lower and upper claddings of the overlay waveguide.

A Study on the Optimization of Silicon Antiresonant Reflecting Optical Waveguides (ARROW) for Integrated Optical Sensor Applications (집적광학 센서 응용에 적합한 실리콘 비공진 반사형 광도파로 최적화에 관한 연구)

  • Jung, Hong-Sik
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.10 no.5
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    • pp.153-160
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    • 2010
  • We optimized the Si(substrate)/$SiO_2$(cladding)/$Si_3N_4$(antiresonant cladding)/$SiO_2$(core)/air multi-layers rib-optical waveguides of antiresonant reflecting optical waveguide (ARROW) for integrated optical biosensor structure utilizing beam propagation method (BPM). Thickness of anti-resonant cladding was derived to minimize the propagation loss and leaky field mode deeply related with evanescent mode was theoretically derived. Depth, width, refractive index and cladding thickness of anti-resonant cladding were numerically calculated into 2.3${\mu}m$, 5${\mu}m$, 1.488, and 0.11${\mu}m$ respectively to minimize propagation loss using the BPM simulation tool. Finally one- and two-dimensional propagation characteristics of ARROW was confirmed.

A novel vertical directional coupler with polarization independent very short coupling lengths (편광에 무관한 매우 짧은 결합 길이를 가지는 새로운 수직 방향성 결합기)

  • 정병민;김부균
    • Korean Journal of Optics and Photonics
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    • v.14 no.4
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    • pp.359-364
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    • 2003
  • We propose a novel vertical directional coupler with polarization independent very short coupling lengths using the double-sided deep-ridge waveguide structure which could be implemented using double-sided process to polarization insensitive deep-ridge waveguide structures and investigate the effect of various structure parameters on the coupling length. Variation of coupling length for the variation of the waveguide width is smaller than that for the variation of the core thickness. Coupling length decreases as the inner cladding layer thickness and the core thickness decrease. The waveguide width with the polarization independent coupling length decreases as the inner cladding layer thickness decreases for the same core thickness and the core thickness decreases for the same inner cladding layer thickness.