• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 추계학술대회논문집
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• pp.792-796
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• 2003

In this paper, to detect external sound frequency on the latticed structure, fiber optic sensor net using Sagnac interferometer was fabricated and tested. The latticed structure fabricated with dimension of 50cm in width and 50cm in height, the optical fiber, 50m in length, distributed and fixed on the latticed structure. Single mode fiber, a laser with 1,550nm in wavelength, 2${\times}$2 coupler were used. External sound signal applied to the fiber optic sensor net and the detected optical signals were compared and analyzed to the detected microphone signals against time and frequency domain. Based on the experimental results, fiber optic sensor net using Sagnac interferometer detected external sound frequency, effectively. This system can be expanded to the structural health monitoring system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 C
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• pp.1669-1670
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• 2006

LED have many problem as narrow light view angle, high price, drift phenomenon of color coordinate, high heating problem for lower power, lower weight and small size. But, with the development of blue LEDs and the improvement of LED brightness, color variation are becoming more and more popular as lighting and application devices in this page, 1 used the Light Tools which was a simulation program in order to recognize optical a few characteristic of LEDs arrangement along reflector matrial and designed LED Arranged 5 phi LED in 5mm interval In the square that was $10{\times}10$ And designs a reflection board on pcb, structural design of PCB changed as five type. - Aluminum, Gold. Chromium, Nickel, Copper.

• Current Optics and Photonics
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• 제3권4호
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• pp.304-310
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• 2019

In this paper, a microstructured, hexagonal-shaped dual-core photonic crystal fiber (PCF) is proposed. The proposed structure has specific optical properties to obtain high birefringence and short coupling length, for different values of structural parameters varied over a wide range of wavelength. The properties are analyzed using a solid core of silica material. The proposed structure is implemented as a polarization splitter with splitting length of 1.9 mm and a splitting ratio of -34.988 dB, at a wavelength of 1550 nm. The obtained bandwidth in one band gap of about 81 nm. The numerical analysis ensures that the performance of the proposed polarization splitter is better than that of existing ones.

• 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.

• 한국광학회지
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• 제14권5호
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• pp.555-564
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• 2003

광통신용 WDM 박막필터를 다중 공동 구조에 의한 방법과 등가 박막을 이용한 방법으로 설계하였고 특징을 비교하였다. 다중 공동 필터는 공동의 수가 증가함에 따라 변수(공동의 수, 각 거울의 주기수, 간격층의 차수)가 많아 설계가 매우 복잡해지므로 보다 실용성 있는 설계를 위해 대칭적으로 변수를 변화시켜 설계하였다. 다중 공동 구조에 의한 방법은 일반적으로 사용되는 4중, 5중 공동 필터를 대칭적으로 변수를 변화시켜 각각 100 ㎓, 50 ㎓ DWDM박막필터를 설계하기 위한 조건을 제시하였고, 또한 다중 공동 필터를 등가 박막으로 해석하여 변수를 최소화하고, 등가 박막의 특성과 WDM 필터의 규격이 대응되도록 설계과정을 일반화시켜 WDM 박막필터를 설계하였다. 두 방법을 비교한 결과 중요한 특징은 다중 공동 구조에 의한 방법은 변수를 적절히 변화시키는 방법을 사용하고 있어 시행착오를 거쳐야 하지만, 등가 박막을 이용한 방법은 체계적이고 정량화된 설계를 할 수 있다.

• Current Photovoltaic Research
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• 제4권3호
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• pp.87-92
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• 2016

The effects of selenization pressure on the structural, optical and electrical properties of the CIGS thin films prepared by RF magnetron sputtering using a single quaternary target were investigated. At selenization pressures lower than atmospheric pressure, CIGS thin films formed non-stoichiometric compounds due to deficiencies of Se vapor. In contrast, when selenization process was conducted at above atmospheric pressure, the residence time of Se vapor inside the tube increased so that the Se element could be incorporated within vacant sites of the CIGS structure, resulting in the formation of stoichiometric CIGS thin films. High quality CIGS thin films could be obtained when the selenization process was performed at pressures greater than atmospheric and $550^{\circ}C$.

• JSTS:Journal of Semiconductor Technology and Science
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• 제3권1호
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• pp.55-61
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• 2003

This paper describes how the optical properties of a quasi-one-dimensional photonic crystalline waveguide having a periodic air cavity are influenced by various structural parameters; the electromagnetic fields are simulated using the finite-difference time-domain method. The simulations considered four design parameters: cavity size, defect size, lattice constant, and number of cavity. The parameter sensitivity of the photonic bandgap property of the waveguide having air cavities is examined. A couple of significant design guidelines are obtained. We show that the quasi-one-dimensional photonic crystalline waveguide has significant unrealized potential.

• Applied Microscopy
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• 제45권2호
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• pp.52-57
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• 2015

Bulk metallic glass (BMG) shows higth strength, high elastic limit, corrosion resistance and good wear resistance and soft magnetic properties and has been considering as a candidate for new structural materials. But they show limited macroscopic plasticity and lack of tensile ductility due to highly localized shear deformation, which should be solved for real structural application. In this paper researches on the enhancement of plasticity of BMG were reviewed briefly. Introducing heterogeneous structure in glass is effective to induce more shear transformation zones (STZs) active for multiple shear band initiation and also to block the propagating shear band. Several methods such as BMG alloy design for high Poisson's ratio, addition of alloying element having positive heat of mixing, pre-straining BMG and variety of BMG composites have been developed for homogenous distribution of locally weak region, where local strain can be initiated. Therefore enhancement of plasticity of BMG is normally accompanied with some penalty of strength loss.

• 한국정밀공학회지
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• 제27권5호
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• pp.69-74
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• 2010

An increasing interest towards the investigations of chalcogenide glasses has been observed in the past years. This interest is due to their specific properties, as well as to the possibilities for their application in different fields of science. The optical devices, working on the basis of photoinduced phase transition between amorphous and crystalline state in the chalcogenide glasses, are a perspective for the micro- and nano-electronics. Here we were analysis basic physical properties for Ge-As-Se and As-Se chalcogenide glasses samples for characteristic for a planning of chalcogenide aspheric lens. From differential DTA/TG results, activation energies of the crystallizations of $Ge_{10}As_{40}Se_{50}$ and $As_{40}Se_{60}$ were approximately 3.6 eV and 3.3 eV, respectively.

• Current Optics and Photonics
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• 제7권5호
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• pp.518-528
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• 2023

As an effective means of remotely detecting the spectral information of the object, the spectral calibration for the Savart polarization interference imaging spectrometer (SPIIS) is a basis and prerequisite of information quantification, and its experimental calibration scheme is firstly proposed in this paper. In order to evaluate the accuracy of the spectral information acquisition, the linear interpolation, cubic spline interpolation, and piecewise cubic interpolation algorithms are adopted, and the precision of the quadratic polynomial fitting is the highest, whose fitting error is better than 5.8642 nm in the wavelength range of [500 nm, 820 nm]. Besides, the inversed value of the spectral resolution for the monochromatic light is greater than the theoretical value, and the deviation between them becomes larger with the wavelength increasing, which is mainly caused by the structural design of the SPIIS, together with the rationality of the spectral restoration algorithm and the selection of the maximum optical path difference (OPD). This work demonstrates that the SPIIS has achieved high performance assuring the feasibility of its practical use in various fields.