• KIEAE Journal
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• 제9권1호
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• pp.69-76
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• 2009

The use of natural light can improve the quality of indoor environment and also occupants health. In recent years, with an increasing awareness of sustainable development, various innovative methods of integrating daylight into the building have been developed. One such device is the light pipe system. The light pipes are innovative daylighting system that allow the transmission of daylight into the hard-to-reach indoor space. The system consist of mainly three parts. First, a top collector which is mounted on the outside of the roof and gathers skylight and sunlight. Second, light-reflective tube which is coated with highly reflective mirror finish material to transmit the daylight into the diffuser. Third, a diffuser which is installed on the ceiling in the room and spread the daylight into the room. Light pipes have been widely used and researched in many countries such as Australia, America, Canada and Britain. However, despite the significant daylight potential, little work have been carried out in Korea compare to the other countries. In this study, recent lighting technology and application of light pipe system in both Korea and other countries have been compared. For the results, the benefits of each light pipe system and suitable application in Korea is also discussed.

• Current Optics and Photonics
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• 제5권3호
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• pp.220-228
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• 2021

To improve the measurement accuracy of a solar-radiation observer instrument, aiming at the problem of multiorder-stray-light interference caused by the diffraction of the flat-field concave grating in the spectroscopic system, straylight suppression methods for different forms of optical traps are studied. According to the grating surface-scattering distribution-function model, the bidirectional scattering distribution function (BSDF) of a dust-polluted surface and the flat-field concave grating's transition area of the spectroscopic system is calculated, and a Lyot stop with blade baffle is designed to suppress this kind of stray light. For diffraction multiorder stray light, based on the theory of light-energy transmission, a design for precise positioning of the trench optical trap is proposed. The superiority of the method is verified through simulation and actual measurement. The simulation results show that in a spectroscopic system approximately 160 mm × 140 mm × 80 mm in size, the energy of the stray light is reduced by one order of magnitude by means of the trench optical trap and Lyot stop, and the number of beams is reduced from 5664 to 1040. The actual measurements show that the stray-light-suppression efficiency is about 69.4%, which is effective reduction of the amount of stray light.

• ETRI Journal
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• 제30권1호
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• pp.164-166
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• 2008

This paper proposes a priority-based duplicate burst transmission mechanism in an optical burst switching network to enhance the probability of successful reception of bursts. The performance of the proposed mechanism is evaluated by NS2 simulations. Our results show that the burst loss rate is improved especially under light traffic loads.

• 대한의용생체공학회:의공학회지
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• 제7권2호
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• pp.159-168
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• 1986

As a fundamental study of Near IR tomography system, transmission parameters of the mongolian breast tissue at 904 nm wavelengh were measured. A analytical model to determin the light intensity in the breast was developed and the measurement, and gheoretical calculations were obtained.

• 한국광학회:학술대회논문집
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• 한국광학회 1991년도 제6회 파동 및 레이저 학술발표회 Prodeedings of 6th Conference on Waves and Lasers
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• pp.121-125
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• 1991

A basic coherent optical transmission was demonstrated using FSK modulation and heterodyne detection scheme. Optical frequency of DFB LD light source at the transmitter side was stabilized with Fabry Perot etalon and bias feedback circuit. A tunable external cavity LD was used as a local oscillator at the receiver. Heterodyned output signal at IF frequency of 2GHz was measured and discussed.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 춘계학술대회 논문집 유기절연재료 전자세라믹 방전플라즈마 연구회
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• pp.66-68
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• 2001

Recently polymer insulators are being used for outdoor high voltage applications. Polymer insulators for transmission and distribution line have significant advantages over porcelain and glass insulators, especially for ultra-high voltage(UHV) transmission lines. Their advantages are light weight, vandalism resistance and hydrophobicity. In this paper, distribution polymer suspension insulator has been designed and investigated electric field distribution by FEM.

• Journal of Electrical Engineering and information Science
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• 제2권6호
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• pp.116-122
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• 1997

The audible noise produced by corona discharge in high voltage transmission lines is the most important line design consideration. In this paper, more accurate and useful formulas for predicting the A-weighted audible noise during heavy and light rain in alternative current (AC) transmission lines are proposed through comparison with the existing formulas. The proposed formulas are developed by the applications of evolutionary computations (ECs) to audible noise data base from long-term measurement.

• 한국약용작물학회지
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• 제16권4호
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• pp.207-210
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• 2008

비닐하우스 내에서 일평균 투광율을 21.2%, 24.8%, 30.3%와 같이 3수준으로, 토양수분을 11.0%, 12.5%, 15.3%, 18.9%와 같이 4수준으로 조절하여 묘삼의 생육 및 수량을 조사한 결과는 다음과 같다. 엽록소 함량은 투광율이 낮은 조건에서 토양수분함량의 감소에 따라 완만히 감소되었으나 투광량이 높은 조건에서 토양수분함량이 낮아지면 엽록소 함량은 현저히 감소되었다.고온장해율은 투광율이 낮은 조건에서 토양수분함량이 11.0%처럼 매우 낮을 때에만 현저히 증가되었지만 투광량이 높은 조건에서는 토양수분함량의 감소에 따라 고온장해율은 급격히 증가되었다. 3.3$m^2$(칸)당 생근중, 주당 생근중 및 사용가능묘삼수는 투광율이 증가되고 토양수분함량이 감소될수록 뚜렷이 감소되었는데, 토양수분함량이 적절한 조건(18.9%)에서는 투광율이 증가되어도 묘삼수량의 감소는 적었으나 토양수분함량이 부족한 조건에서는 투광율이 증가될수록 묘삼수량은 현저히 감소되었다. 적변율은 투광율이 높고 토양수분함량이 많을 때 현저히 증가되었는데, 투광율이 높은 조건에서 토양수분함량이 감소되면 적변율도 차차 감소되었으며, 투광율이 낮은 조건에서 적변율은 토양수분함량에 따라 큰 변화를 보이지 않았다.

• 한국융합학회논문지
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• 제10권12호
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• pp.177-181
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• 2019

본 연구는 광중합기의 청색광을 이용한 치과 치료과정에서 광중합기용 팁들과 보안경의 청색광 차단정도를 알아보기 위해, UV-Vis 스펙트로미터 기기에 광중합기용 팁들과 보안경들을 위치시키고 빛을 투과하여 측정한 결과를 비교 분석하였다. 분석결과, 분석에 사용한 4가지 종류의 광중합기용 팁들 모두 청색광 차단효과가 매우 우수한 것으로 나타났다. 보안경의 경우 붉은색 계열 보안경이 노란색 계열 보안경보다 광중합기용 팁들과 유사한 청색광 투과율을 보여 청색광 차단효과가 더 우수한 것으로 나타났다. 결과적으로 청색광 차단정도가 높은 광중합기용 팁 부착과 보안경 착용이 눈 보호를 위해 필요한 행위임을 추천한다. 이러한 행위는 눈에 대한 지속적인 자극과 피로감을 줄여줄 것이라 사료된다.

• 한국어병학회지
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• 제29권1호
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• pp.7-12
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• 2016

In a previous study on the parasites of cultured rock bream (Oplegnathus fasciatus), we reported the discovery of a new species, Ceratomyxa oplegnathus, obtained from the gallbladder. In the present study, we found another Ceratomyxa species, C. sparusaurati, also from the gallbladder of rock bream. The morphological and ultrastructural characteristics of C. sparusaurati were investigated using light and transmission electron microscopy (TEM).