• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2008년도 추계학술대회 논문집
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• pp.157-160
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• 2008

색온도 및 광색 가변형 100W RGBY LED 투광기를 개발하기 위하여, 투광기의 광학 및 방열기구를 설계하였다. 또한 100W LED 광원모듈을 구동하기 위한 구동회로와 색온도 및 광색 가변을 위한 제어회로를 개발하였다. 이와 같은 설계결과를 적용하여 100W RGBY 투광기의 시제품을 제작하였고, 시제품의 광학적 성능은 협각 $20^{\circ}$, 중각 $50^{\circ}$, 광각 $75^{\circ}$이상을 만족시켰다. 또한 색온도의 변화는 CIE 1931 색좌표에서 흑체궤적과 일치하여 $2,000K{\sim}10,000K$까지 변화하도록 R,G,B,Y LED의 Duty Ratio를 설정하였다. 또한 방열 특성은 100W 구동시 녹색 LED의 온도는 $37{\sim}41.3^{\circ}C$, heatsink의 온도는 $34{\sim}35^{\circ}C$에서 동작되도록 하였다.

• 산업기술연구
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• 제27권B호
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• pp.121-123
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• 2007

As a reflector of reference arm in OCT systems, a coated fiber reflector has mostly used. Instead, this paper has realized the swaept source optical coherence tomography system using a loop mirror within a reference arm. Through the experiments for a tilted thin glass plate, we found that the loop mirror is better than the coated fiber typed mirror for obtaining the clear image.

• 한국전자파학회논문지
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• 제9권3호
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• pp.338-346
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• 1998

천정에 부착한 구상 리플렉터와 송수신 공용 양선 원편파 안테나를 조합하여 옥내무선통신망을 실현하려 한 다. 먼저, 시스댐 실현에 앞서, 본 논문에서는 도체구의 산란패턴을 벡터 구파동함수를 이용한 계산 및 실측한 결과 후방산란영역(이하 명영역이라 칭함)에서 안정한 전방향 산란레벨 유지를 확인하였으며 13 dB 이상의 펀파분리도도 확보되었다. 따라서 완전도체구의 명영역 전방향 산란특성을 기반으로 구상 리플랙터가 제안 힌 옥내무선통신시스템에 유효함음 확인했다.

• 한국전자파학회논문지
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• 제9권3호
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• pp.330-337
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• 1998

본 논문에서는 천정에 부착할 분구형 리플렉터를 이용한 마이크로파대의 새로운 옥내 무선통신시스템을 구축하는데 필요한 반구형 리플렉터의 산란특성 및 옥내 전파특성을 평가하기 위해 송수신 공용 원편파 양선 코니칼 혼안테나를 설계, 제작하고 그 제특성을 구했다. 그 결과, 편파식별도 27 dB이상, 축비 1.25 dB 이하의 양호한 원편파 양선출력 특성이 얻어졌다.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2006년도 춘계학술대회 논문집
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• pp.154-156
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• 2006

A few ten mW white LED can substitute for the indicator light source and it is required to study several watt multi-chip semiconductor light sources in order to replace the light sources for general illumination such as incandescent lights and fluorescent lanes. Since the optical technology used for several mW white LED light source uses only 30% to 52% of the light it is required to develop the design technology of optical system and lens to improve the efficiency more than 80% for insuring the high power of white LED. In this paper, we designed and fabricated new structure reflector to increase the efficiency and is easy to make high power multi-chip LED lamp.

• 한국군사과학기술학회지
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• 제13권6호
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• pp.1133-1138
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• 2010

We have developed an imaging radiometer system at W-band. The system consists of lens, reflector, 30-ch receiver array, scanner, and signal processor. One receiver consists of a dielectric rod antenna, a balun, LNA(low noise amplifier) and a detector. The system configuration requirements are described. Finally, we represent radiometer images to obtain through clouds, smoke, dust, and other obstructions which render visible and IR systems ineffective.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제43회 하계 정기 학술대회 초록집
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• pp.251-252
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• 2012

Recently, the growing interest in organic microelectronic devices including OLEDs has led to an increasing amount of research into their many potential applications in the area of flexible electronic devices based on plastic substrates. However, these organic devices require a gas barrier coating to prevent the permeation of water and oxygen because organic materials are highly susceptible to water and oxygen. In particular, high efficiency OLEDs require an extremely low Water Vapor Transition Rate (WVTR) of $1{\times}10^{-6}g/m^2$/day. The Key factor in high quality inorganic gas barrier formation for achieving the very low WVTR required ($1{\times}10^{-6}g/m^2$/day) is the suppression of defect sites and gas diffusion pathways between grain boundaries. In this study, we developed an $Al_2O_3$ nano-crystal structure single gas barrier layer using a Neutral Beam Assisted Sputtering (NBAS) process. The NBAS system is based on the conventional RF magnetron sputtering and neutral beam source. The neutral beam source consists of an electron cyclotron Resonance (ECR) plasma source and metal reflector. The Ar+ ions in the ECR plasma are accelerated in the plasma sheath between the plasma and reflector, which are then neutralized by Auger neutralization. The neutral beam energies were possible to estimate indirectly through previous experiments and binary collision model. The accelerating potential is the sum of the plasma potential and reflector bias. In previous experiments, while adjusting the reflector bias, changes in the plasma density and the plasma potential were not observed. The neutral beam energy is controlled by the metal reflector bias. The NBAS process can continuously change crystalline structures from an amorphous phase to nano-crystal phase of various grain sizes within a single inorganic thin film. These NBAS process effects can lead to the formation of a nano-crystal structure barrier layer which effectively limits gas diffusion through the pathways between grain boundaries. Our results verify the nano-crystal structure of the NBAS processed $Al_2O_3$ single gas barrier layer through dielectric constant measurement, break down field measurement, and TEM analysis. Finally, the WVTR of $Al_2O_3$ nano-crystal structure single gas barrier layer was measured to be under $5{\times}10^{-6}g/m^2$/day therefore we can confirm that NBAS processed $Al_2O_3$ nano-crystal structure single gas barrier layer is suitable for OLED application.

• Journal of Radiation Protection and Research
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• 제8권1호
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• pp.33-37
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• 1983

물 또는 콘크리트반사체(反射體)의 두께 및 콘크리트반사체(反射體)와 핵물질용액계(核物質溶液系) 사이의 간격에 따라 변(變)하는 유효증배계수(有效增倍係數)로서의 반사효과(反射效果)를 중성자수송이론(中性子輸送理論)에 기초를 둔 각분할방법(角分割方法)의 전산코드 ANISN으로 계산하였다. 그 결과에 따르면 반사체(反射體)의 두께가 엷을 때, 유효증배계수(有效增倍係數)를 기준으로 한 물 반사체(反射體)의 반사효과(反射效果)는 콘크리트에서보다 크지만 그 두께가 커지면 반대현상도 생기는 것 같았다. 한편 핵물질용액계(核物質溶液系)와 콘크리트반사체(反射體)사이에 물이 채워져 있고 그 간격변화에 따라 산출한 유효증배계수치(有效增倍係數値)는 처음 급격하게 감소하다가 약 15cm를 지나면서부터 서서히 감소하는 것 같았다.

• 한국추진공학회지
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• 제21권4호
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• pp.36-43
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• 2017

격벽착화기의 최적 설계를 위하여 여폭약에 의해 생성되는 충격파의 감쇄 특성과 수폭약의 민감도에 관하여 연구하였다. 충격파의 감쇄 특성은 레이저 광간섭계인 VISAR를 이용하여 측정한 격벽의 자유 표면 속도로부터 유도하였고 수폭약의 민감도는 SSGT (Small Scale Gap Test) 결과로부터 구하였다. 격벽착화기의 기폭시험을 통하여 SSGT로부터 구한 화약의 민감도가 격벽착화기와 같이 소량의 화약을 사용하는 시스템에는 충격파 지속 시간이 상이하여 적합하지 않다는 것을 밝혀내었다.

• Anatomy and Cell Biology
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• 제56권1호
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• pp.25-31
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• 2023

Johannes Nathanael Lieberkühn was a prodigious anatomist whose meticulous experiments and precise detailing helped in comprehending the microscopic anatomy of digestive system during early part of eighteenth century. Notably, his inventions in the field of microscopy aptly complemented his quest for anatomical knowledge at microscopic level. He designed a reflector (Lieberkühn reflector) which enhanced the amount of focussed light leading to bright illumination of tissue specimen. He invented the solar microscope which provided excellent resolution of minute anatomical details. Lieberkühn discovered the digestive juice secreting tubular glands (glands of Lieberkühn) present at the base of intestinal villi producing epithelial invaginations (crypts of Lieberkühn). He also described the intricate juxtaposition of blood vessels in relation to a single intestinal villi. Moreover, through empirically designed experimental set up, Lieberkühn was able to demonstrate the flow of lymph from intestinal villi to collecting lymphatic vessels. Also, his grandiose collection of laboratory specimens involving vascular anatomy are a testimony of his untiring efforts in academia. His contributions were seminal in comprehending the anatomy of digestive system and paved the way for future revelations. His work unveiled the enormous scope of microanatomy in medical science and catalysed the advent of histological staining methods a century later.