Korean Journal of Optics and Photonics最新文献_第4页

Development of Digital-Image-Correlation Technique for Detecting Internal Defects in Simulated Specimens of Wind Turbine Blades 风电叶片模拟试件内部缺陷检测的数字图像相关技术研究

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Korean Journal of Optics and Photonics Pub Date : 2020-01-01 DOI: 10.3807/KJOP.2020.31.5.205

Kyung-min Hong, N. Park

{"title":"Development of Digital-Image-Correlation Technique for Detecting Internal Defects in Simulated Specimens of Wind Turbine Blades","authors":"Kyung-min Hong, N. Park","doi":"10.3807/KJOP.2020.31.5.205","DOIUrl":"https://doi.org/10.3807/KJOP.2020.31.5.205","url":null,"abstract":"In the performance of a wind turbine system, the blades play a vital role. However, they are susceptible to damage arising from complex and irregular loading (which may even cause catastrophic collapse), and they are expensive to maintain. Therefore, it is very important both to find defects after blade manufacturing is completed and to find damage after the blade is used for a certain period of time. This study provides a new perspective for the detection of internal defects in glass-fiber-and carbon-fiber-reinforced panels, which are used as the main materials in wind turbine blades. A gap or fracture between fiber-reinforced materials, which may occur during blade manufacturing or operation, is simulated by drilling a hole 5 mm in diameter in the middle layer of the laminated material. Then, a digital-image-correlation (DIC) method is used to detect internal defects in the blade. Tensile load is applied to the fabricated specimen using a tensile tester, and the generated changes are recorded and analyzed with the DIC system. In the glass-fiber-reinforced laminated specimen, internal defects were detected from a strain value of 5% until the end of the experiment, while in the case of the carbon-fiber-reinforced laminated specimen, internal defects were detected from 1% onward. It was proved using the DIC system that the defect was detected as a certain level of strain difference developed around the internal defects, according to the material properties.","PeriodicalId":42467,"journal":{"name":"Korean Journal of Optics and Photonics","volume":"31 1","pages":"205-212"},"PeriodicalIF":0.1,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70162108","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Design and Performance of a Catadioptric Omnidirectional Zoom Optical System Using a Hybrid Lens for Visible Light 可见光混合透镜反射全向变焦光学系统的设计与性能

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Korean Journal of Optics and Photonics Pub Date : 2020-01-01 DOI: 10.3807/KJOP.2020.31.2.096

Hyunuk Park, J. Jo

引用次数: 0

Polyperiodic-hole-array Plasmonic Color Filter for Minimizing the Effect of Angle of Incidence 最小入射角影响的多周期孔阵列等离子体彩色滤光片

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Korean Journal of Optics and Photonics Pub Date : 2020-01-01 DOI: 10.3807/KJOP.2020.31.3.148

Ki Won Jeong, Y. Do

引用次数: 0

Band-switchable Terahertz Metamaterial Based on an Etched VO 2 Thin Film 基于刻蚀VO 2薄膜的能带切换太赫兹超材料

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Korean Journal of Optics and Photonics Pub Date : 2020-01-01 DOI: 10.3807/KJOP.2020.31.1.031

H. Ryu

{"title":"Band-switchable Terahertz Metamaterial Based on an Etched VO 2 Thin Film","authors":"H. Ryu","doi":"10.3807/KJOP.2020.31.1.031","DOIUrl":"https://doi.org/10.3807/KJOP.2020.31.1.031","url":null,"abstract":"테라헤르츠파는 전자기파 스펙트럼에서 마이크로파와 원 적외선의 중간 영역에 해당하는 0.1~10 THz 대역의 주파수 자원으로, 마이크로파 생성 기술과 광파 생성 기술 모두 적 용하기 어려워 오랜 기간 동안 미개발되어 ‘테라헤르츠 갭 (terahertz gap)’으로 불리어 왔다. 이러한, 테라헤르츠파는 전 파의 투과성과 광파의 직진성을 동시에 가지고 있고, 분자 운동의 진동주파수 영역이 테라헤르츠파 주파수 대역에 존 재하므로 물질의 성분 분석에 적합하여 물질의 물성, 분자, 생명 연구 등을 위한 분광 시스템, 이미징 시스템, 그리고 넓 은 주파수 대역폭을 이용한 초고속 무선 통신 시스템 등 다 양한 분야에 응용이 가능하여 많은 연구가 진행되고 있다 . 그러나 실질적으로 테라헤르츠 대역에서 사용 가능한 소자의 개발은 자연계 물질의 전기적, 자기적 특성이 테라헤 르츠파 주파수 대역에서 소자로 활용되기에 적합하지 않아 마이크로파나 광파 대역에 비교하여 매우 부족한 상황이다. 그러므로 인공적으로 전기/자기적 특성을 제어할 수 있는 메 타물질을 테라헤르츠파의 소자로서 활용하는 연구가 많은 관심을 받아 왔다. 메타물질은 관심 파장보다 작은 크기의 유닛 셀을 금속이나 유전체 물질을 이용하여 형성하고 주기 적으로 배열하여 전체 구조를 균일한 물질로 인식하도록 인 Band-switchable Terahertz Metamaterial Based on an Etched VO2 Thin Film","PeriodicalId":42467,"journal":{"name":"Korean Journal of Optics and Photonics","volume":"31 1","pages":"31-36"},"PeriodicalIF":0.1,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70160731","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Forensic Classification of Latent Fingerprints Applying Laser-induced Plasma Spectroscopy Combined with Chemometric Methods 激光诱导等离子体光谱与化学计量相结合的法医潜指纹分类

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Korean Journal of Optics and Photonics Pub Date : 2020-01-01 DOI: 10.3807/KJOP.2020.31.3.125

Yang Jun-Ho, Yoh, Jai-Ick

{"title":"Forensic Classification of Latent Fingerprints Applying Laser-induced Plasma Spectroscopy Combined with Chemometric Methods","authors":"Yang Jun-Ho, Yoh, Jai-Ick","doi":"10.3807/KJOP.2020.31.3.125","DOIUrl":"https://doi.org/10.3807/KJOP.2020.31.3.125","url":null,"abstract":"An innovative method for separating overlapping latent fingerprints, using laser-induced plasma spectroscopy (LIPS) combined with multivariate analysis, is reported in the current study. LIPS provides the capabilities of real-time analysis and high-speed scanning, as well as data regarding the chemical components of overlapping fingerprints. These spectra provide valuable chemical information for the forensic classification and reconstruction of overlapping latent fingerprints, by applying appropriate multivariate analysis. This study utilizes principal-component analysis (PCA) and partial-least-squares (PLS) techniques for the basis classification of four types of fingerprints from the LIPS spectra. The proposed method is successfully demonstrated through a classification example of four distinct latent fingerprints, using discrimination such as soft independent modeling of class analogy (SIMCA) and partial-least-squares discriminant analysis (PLS-DA). This demonstration develops an accuracy of more than 85% and is proven to be sufficiently robust. In addition, by laser-scanning analysis at a spatial interval of 125 μm, the overlapping fingerprints were separated as two-dimensional forms.","PeriodicalId":42467,"journal":{"name":"Korean Journal of Optics and Photonics","volume":"31 1","pages":"125-133"},"PeriodicalIF":0.1,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70161366","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Adiabatic Optical-fiber Tapers for Efficient Light Coupling between Silicon Waveguides and Optical Fibers 用于硅波导和光纤之间有效光耦合的绝热光纤锥

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Korean Journal of Optics and Photonics Pub Date : 2020-01-01 DOI: 10.3807/KJOP.2020.31.5.213

Gyeongho Son, Jiwon Choi, Jeong Youngjae, Kyoungsik Yu

引用次数: 0

High-beam-quality 2-kW-class Spectrally Combined Laser Using Narrow-linewidth Ytterbium-doped Polarization-maintaining Fiber Amplifiers 窄线宽掺镱保偏光纤放大器的高光束质量2 kw级频谱组合激光器

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Korean Journal of Optics and Photonics Pub Date : 2020-01-01 DOI: 10.3807/KJOP.2020.31.5.218

Hwanseong Jeong, K. Lee, Junsu Lee, Dongjoon Kim, Jeonghwan Lee, Minsik Jo

引用次数: 2

A Study of the Fiber Fuse in Single-mode 2-kW-class High-power Fiber Amplifiers 单模2 kw级大功率光纤放大器中光纤保险丝的研究

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Korean Journal of Optics and Photonics Pub Date : 2020-01-01 DOI: 10.3807/KJOP.2020.31.1.007

Junsu Lee, K. Lee, Hwanseong Jeong, Dong J. Kim, Jung Hwan Lee, Minsik Jo

{"title":"A Study of the Fiber Fuse in Single-mode 2-kW-class High-power Fiber Amplifiers","authors":"Junsu Lee, K. Lee, Hwanseong Jeong, Dong J. Kim, Jung Hwan Lee, Minsik Jo","doi":"10.3807/KJOP.2020.31.1.007","DOIUrl":"https://doi.org/10.3807/KJOP.2020.31.1.007","url":null,"abstract":"In this paper, we experimentally investigate the fiber fuse in single-mode 2-kW-class high-power fiber amplifiers, depending on the cooling method at the splicing point. We measured the temperature of the splicing point between the pump-signal combiner and gain fiber as a function of laser output power. The temperature of the splicing point increased from 20 to 32°C with a slope of 0.01°C/W, up to 1.2 kW of laser output power. At higher powers the temperature of the splicing point increased dramatically, with a slope of 0.08°C/W. After that, the fiber amplifier was destroyed during operation at 1.96 kW of output power by fiber fuse. The bullet shape, a common feature of fiber fuse, was observed in the damaged passive fiber core of the pump-signal combiner. Later, we adopted an improved water-cooled cold plate to increase the cooling efficiency at the splicing point, and investigated the laser output power. The temperature at the splicing point was 35.8°C with a temperature-rise slope of 0.007°C/W at the maximum output power of 2.05 kW. The beam quality M2 was measured to be less than 1.3, and the output beam’s profile was a stable Gaussian shape. Finally, neither fiber fuse nor mode instability was observed in the fiber amplifier at the maximum output power of 2.05 kW.","PeriodicalId":42467,"journal":{"name":"Korean Journal of Optics and Photonics","volume":"31 1","pages":"7-12"},"PeriodicalIF":0.1,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70160599","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Feasibility Study of the Light-outcoupling Characteristics of a Diffraction-grating-imprinted Light-guide Plate for an LCD Backlight Unit LCD背光器件用衍射光栅压印导光板光解耦特性的可行性研究

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Korean Journal of Optics and Photonics Pub Date : 2020-01-01 DOI: 10.3807/KJOP.2020.31.4.176

Hwan-young Choi

引用次数: 0

Analysis of Quality Improvement of a Floating Image Using a Hybrid Retroreflective Mirror Array Sheet 利用混合型后向反射镜阵列片提高浮动图像质量的分析

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Korean Journal of Optics and Photonics Pub Date : 2019-08-01 DOI: 10.3807/KJOP.2019.30.4.142

D. Yu, Young Jae Baek, Hyeon Joong Yong, O. Beomhoan

引用次数: 0