• 한국통신학회논문지
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• 제28권5A호
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• pp.323-332
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• 2003

본 논문에서는 광원이 불필요하며 단일 광섬유를 통하여 양방향 전송이 가능한 base station용 광송수신기 모듈을 제안하였다. 제안한 시스템에서는 써큘레이터와 Mach-Zehnder 변조기로 구성된 ring-type의 base station에서 central office로부터 하향 전송된 광신호의 일부를 재사용하여 상향신호 전송에 사용한다. 시스템의 성능을 평가하기 위해서 IS-95 CDMA 신호 전송을 통한 ACPR 특성과 14개의 캐리어 신호 전송을 통한 CNR을 측정하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 추계학술대회 논문집 학회본부
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• pp.508-510
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• 1995

A fiber-optic pressure sensor is fabricated with a photoelastic glass material. To remove the influence of external pertubation along the optical fiber, a new referencing technique is proposed by using two light sources. LED with 870nm wavelength is used as light source for reference signal, and LED with 660nm wavelength is used as light source for modulation signal. The fiber-optic pressure sensor system shows good linearity within the pressure range of 0 to 5 $kg/cm^2$.

• 전자공학회논문지B
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• 제32B권11호
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• pp.1481-1488
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• 1995

Due to the low loss, broadband and accurate short time delay properties of optical fiber, it has attracted as a delay medium for high speed and broad-band signal processing. In this paper, we consider the coherent optical fiber filter of IIR lattice structure, which uses coherent light sources and consists of directional couplers whose coupling coefficients are restricted between 0 and 1. Considering restrictions of directional coupler, the design formulae and condition for realibility of optical fiber filter of IIR lattice structure which makes the optimal use of optical signal energy are derived.

• Applied Biological Chemistry
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• 제36권2호
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• pp.73-79
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• 1993

식물성 섬유질 함유 자원으로부터 식품의 가공적성을 떨어뜨리지 않으면서 우수한 기능특성을 보이는 식이섬유원을 제조할 목적으로 대량 수급이 용이한 사과쥬스박과 두유박에 식이섬유의 함량을 높이고 기능성을 향상시키기 위한 각종 처리를 행하여 식이섬유원을 제조하였다. 사과쥬스박은 마쇄, 수세 및 사별에 의하여 사과육과 사과피로 분리할 수 있었는데 사과육이 사과피보다 기능성이 우수하였고 사과육은 수세, n-hexane 처리 등에 의해 WHC 11.27 g/g, FHC 2.01 g/g, CEC 64.96 meq/100g의 기능성을 보이며 60.94%의 NDF를 함유한 제품을 제조할 수 있었다. 두유박을 이용한 식이섬유원 제조에서는 수세, n-hexane처리, 산처리, 알칼리처리 등의 처리로 WHC 10.15 g/g, FHC 1.52 g/g, CEC 63.72 meq/100g의 기능성을 보이며 52.66%의 NDF 함량을 갖는 식이섬유원이 제조되었다. 이때 원료로부터의 회수율은 사과육의 경우 약 30%, 처리두유박의 경우는 38.2%이었다. 식이섬유질원의 색도는 수세시 명도를 효과적으로 증가시킬 수 있었으나 유기용매, 산 및 알칼리 처리에 의해서는 명도가 감소하였다.

• 한국해양공학회지
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• 제16권4호
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• pp.48-53
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• 2002

Fiber-reinforced composites are extensively used in electronic, ship and aerospace applications due to their high strength and high toughess. In these applications, they are often subjected to localized heat damage due to various sources. In order to ensure their reliability, it is important to predict their residual properties using nondestructive evaluation thchniques. Fabric fiber composite specimens were manufactured with six layers of the glass-fiber prepreg and the carbon-fiber prepreg, respectively. The specimens were subjected to a localized heat damage using a heated copper tip with a diameter of 10mm at 35$0^{\circ}C$(CFRP) and 30$0^{\circ}C$(GFRP), respectively. The specimens were then subjected to tension tests while acoustic emission (AE) activities of specimens were collected. The AE activity of all specimens showed three types of distinct frequency regions. Those are matrix cracking, failure of the fiber/matrix interface and fiber breakage.

• Journal of Nutrition and Health
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• 제30권8호
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• pp.895-903
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• 1997

This study was performed to investigate the influence of dietray food from the three CHinese medicinal herbs(Mugwort, Dried organge peel and Duchung) on lipi d metabolism in rats. Male rats of Sprague-Dawley strain were divided into four dietary groups(Cellulose (CL), Mugwort(MW), Dried organge peel9OP), Duchung(DC)) after three weeks of hyperlipidemic dieting and were fed ad libitum each of the experimental diets for six weeks. The fiber sources of the experimental diets were prepared by drying and milling mugwort, orange peel, duchung and cellulose. Each of the Fiber sources was mixed into the diet to achieve 10g% levels of total dietary fiber. Levels of apparent fat absorption exhibited a significant decrease in the MW and DC groups. The OP group also showed a decreasing trend, but to a lesser extent. The levels of serum total lipid were not significantly different among the four experimental groups. Total serum cholesterol levels were significantly lower in the OP grop that in both the CM and MW group. Serum TG and LDL-cholesterol levels were significantly higher in the DL group than other groups. Serum HDL-cholesterol levels were significantly levels were significantly lower in the CL group than in the other groups. Total lipid and total cholesterol in liver were significantly higher in the CL group than in the other groups. Total lipid and total cholesterol in feces displayed a significantly increase in the MW and DC groups when compared with the CL group. The OP group also showed an increase compared to the CL group.

• Nuclear Engineering and Technology
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• 제53권10호
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• pp.3431-3437
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• 2021

In this study, one-dimensional gamma ray source positions are estimated using a plastic scintillating optical fiber, two photon counters and via data processing with a machine learning algorithm. A nonlinear regression algorithm is used to construct a machine learning model for the position estimation of radioactive sources. The position estimation results of radioactive sources using machine learning are compared with the theoretical position estimation results based on the same measured data. Various tests at the source positions are conducted to determine the improvement in the accuracy of source position estimation. In addition, an evaluation is performed to compare the change in accuracy when varying the number of training datasets. The proposed one-dimensional gamma ray source position estimation system with plastic scintillating fiber using machine learning algorithm can be used as radioactive leakage scanners at disposal sites.

• Current Optics and Photonics
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• 제6권6호
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• pp.521-549
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• 2022

Fiber lasers have made remarkable progress over the past three decades, and they now serve far-reaching applications and have even become indispensable in many technology sectors. As there is an insatiable appetite for improved performance, whether relating to enhanced spatio-temporal stability, spectral and noise characteristics, or ever-higher power and brightness, thermal management in these systems becomes increasingly critical. Active convective cooling, such as through flowing water, while highly effective, has its own set of drawbacks and limitations. To overcome them, other synergistic approaches are being adopted that mitigate the sources of heating at their roots, including the quantum defect, concentration quenching, and impurity absorption. Here, these optical methods for thermal management are briefly reviewed and discussed. Their main philosophy is to carefully select both the lasing and pumping wavelengths to moderate, and sometimes reverse, the amount of heat that is generated inside the laser gain medium. First, the sources of heating in fiber lasers are discussed and placed in the context of modern fiber fabrication methods. Next, common methods to measure the temperature of active fibers during laser operation are outlined. Approaches to reduce the quantum defect, including tandem-pumped and short-wavelength lasers, are then reviewed. Finally, newer approaches that annihilate phonons and actually cool the fiber laser below ambient, including radiation-balanced and excitation-balanced fiber lasers, are examined. These solutions, and others yet undetermined, especially the latter, may prove to be a driving force behind a next generation of ultra-high-power and/or ultra-stable laser systems.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.1723-1726
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• 2008

In recent years, there has been a remarkable progress in the development of the fiber optic sensors for the detection of various chemicals. Fiber optic sensors have the advantages of very small size, flexibility and low cost. The fiber optic sensors employing different optical or spectroscopic phenomena have been reported such as bulk absorption, optical reflectance, fluoresces and energy transfer. In this study, the effect of nanoparticle concentration in liquid upon light absorption and scattering was studied using extrinsic fiber optic method. For the evaluation, we used Red (650 nm) and Blue (430 nm) light sources which are coupled through the standard cuvette using optical fiber to detector. The experiments are carried out with Polystyrene latex (400 - 800 nm), and Silicon (35 - 110 nm) nanoparticles suspended in Isopropanol. Differences in light absorption and scattering depending on nanoparticle concentration and type are discussed. This method may be useful to study nanoparticles properties for various application and research.

• 한국식품영양과학회지
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• 제23권5호
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• pp.767-773
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• 1994

1989년도 국민영양조사의 식품섭취조사에서 조사된 전국규모의 자료를 중심으로총 566종의 식품에 대해 식이성섬유소 분석치를 적용하여 그 섭취량을 분석한결과는 다음과 같다. 식이성섬유소의 섭취량은 전국이 17.53g, 도시평균이 17.91g, 대도시가 18.07g, 중소도시가 17.56g, 농촌이 16.61g으로 나타났으며, 이중 95% 정도를 식물성 식품으로 부터 섭취하고 있었다. 식품군별 식이성섬유소 섭취의 기여도는 채소류>곡류 및 그 제품>해조류>과실류>버섯류>두류 및 그 제품의 순이었다. 곡류 및 그 제품에서 가장 중요한 급원은 쌀로 전국평균이 12.2%였으며, 그 다음이 라면, 식빵, 보리쌀의 순이었으며, 해조류에서 가장 중요한 급원은 미역이었고, 그 다음이 김과 파래였다. 과실류에서는 사과와 감이 버섯류에서는 느타리버섯과 표고버섯이, 두류에서는 콩나물이 식이성섬유소의 중요한 급원이었다. 채소류는 식이성섬유소의 가장 중요한 급원으로, 전국의 경우 32.4%, 도시평균은 31.4%, 대소시에서는 30.8%, 중소도시에서는 33.0%, 농촌에서는 34.8%를 차지하였다. 그 중 가장 중요한 급원은 배추김치와 붉은 고추가 1, 2위를 차지하였다. 전국적으로 식이성섬유소 섭취량 분포를 보면 도수분포(Frequency distribution)의 계급구간을 5g으로 섭취하는 가구로 33.9%를 차지하엿고, 5g 이하나 35g 이상 섭취하는 가구도 0.8%와 5.2%를 나타내었다.