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높은 개구수를 갖는 다성분계 Glass Fiber의 제조 및 특성
이희관,오영석,이용수,강원호 단국대학교 신소재기술연구소 2002 신소재 Vol.11 No.-
광전자 기술의 발전 및 광 응용 분야의 확대에 따라 광전송장치 사용이 증가하고 있으며, 이에 따라 광원과 광link사이에 불일치로 나타나는 손실을 줄일 수 있고, 다량의 정보를 전송할 수 있는 개구수가 큰 fiber개발이 대두되고 있다. 이에 본 연구에서는 보다 높은 개구수(numerical aperature : N.A.)를 갖는 fiber 제조를 위하여 SiO_2, PbO를 주성분으로 하고 K_2O, Na_2O, B_2O_3, Al_2O_3 등의 산화물을 적량 배합함으로써 core-clad 유리의 제조 및 제조된 유리의 물성 평가를 하였으며, double crucible method를 이용하여 fiber를 제조하였다. 또한 제조된 fiber의 구조적 및 기계적 특성을 관찰하였다. It is increasing to uses of the photo transmission devices because of development in photoelectronic techniques and enlargement of photo application fields. Therefore, we need to the optical fiber to transmit lots of information and decrease optical loss. For high-numerical aperture optical fiber, in this study, main components are SiO_2, PbO and glass composition mix component oxide such as K_2O, Na_2O, B_2O_3, Al_2O_3, Also, the optical, mechanical, structural properties of manufactured glasses and fibers by double crucible method are investigated.
Integrated Environment Impact Assessment of Brick Kiln using Environmental Performance Scores
이희관,Rajib Pokhrel 한국대기환경학회 2014 Asian Journal of Atmospheric Environment (AJAE) Vol.8 No.1
The capital city of Himalayan Country Nepal, Kathmandu Valley is surrounded by consecutive high mountains, which limits the air distribution and mixing effects significantly. It in turn generates steady air flow pattern over a year except in monsoon season. The air shed in the Valley is easily trapped by the surrounded mountains and the inversion layer formulated as the cap. The PM10 concentration was noticeably higher than the standard level (120 μg/m3) in urban and suburban area of Kathmandu valley for all seasons except monsoon period. The Valley area experiences similar wind patterns (W, WWS, and S) for a year but the Easterly wind prevails only during the monsoon period. There was low and calm wind blows during the winter season. Because of this air flow structure, the air emission from various sources is accumulated within the valley air, high level of air pollution is frequently recorded with other air polluted cities over the world. In this Valley area, brick kilns are recognized as the major air pollution source followed by vehicles. Mostly Bull Trench Kiln (BKT), Hoffman Kiln and Vertical Shaft Brick Kiln (VSBK) are in operation for brick firing in Kathmandu valley where the fuels such as crushed coal, saw dust, and natural gas are used for processing bricks in this study. Tool for the Reduction and Assessment of Chemical and Other Environmental Impacts (TRACI) was used for screening and quantifying the potential impacts of air emission from firing fuels. The total Environmental Performance Score (EPS) was estimated and the EPS of coal was approximately 2.5 times higher than those of natural gas and saw dust. It is concluded that the crushed coal has more negative impact to the environment and human health than other fuel sources. Concerning the human health and environment point of view, alternative environment friendly firing fuel need to be used for brick industry in the kiln and the air pollution control devices also need to be applied for minimizing the air emissions from the kilns.
乾隆帝와 郭葆昌 그리고 Percival David ―汝窯瓷器의 실체에 대한 인식의 궤적과 이른바 傳世汝窯瓷器
이희관 한국미술사교육학회 2015 美術史學 Vol.- No.30
It is known that about 70 pieces of Ru wares have been passed down today. They are so-called surviving Ru wares. How did they become recognized as Ru wares? Furthermore, are they true Ru wares? In the early 20thcentury when the researches on Ru ware began to be systemically carried out, Qingbai (or Yingqing) ware was recognized as Ru type ware or so-called Northen Celadon known was recognized as Ru ware. Such a misunderstanding was a byproduct of the period when researchers were almost blocked from practical resources of Ru ware, in other words, the dark ages of the research on Ru ware. It is thought to be Guobaochang who built the foundation to recognize the known Tianqing ware as Ru ware today. He discovered what kind of potteries were identified as Ru ware by Emperor Qianlong after finding and comparing the poems written on the specific pottery in The Collection of Emperor Qianlong’s Poems(御製詩集). Based on the ground, he recognized the type of potteries known as surviving Ru ware as Ru ware. Such recognition was organized by Percival David. Most researchers believe that it is an indisputable truth that the materials known as surviving Ru ware refer to Ru ware after the Qingliangsi Ru kiln 오늘날 70여 점의 여요자기가 전해오는 것으로 알려져 있다. 이른바 전세여요자기가 그것이다. 이들은 어떻게 여요자기로 인식되게 된 것일까? 더 나아가 이들은 진정 여요자기인 것일까? 여요자기에 대한 연구가 체계적으로 이루어지기 시작한 20세기 초에는 청백자(影靑瓷)가 汝窯系라거나, 오늘날 耀州窯産으로 알려진 이른바 북방청자로 여요자기로 인식하였다. 이러한 착오는 연구자들이 여요자기의 실물자료로부터 거의 차단되어 있던 시기, 즉 여요연구의 암흑기의 산물이었다. 오늘날 우리가 알고 있는 천청유자기를 여요자기로 인식하는 토대를 구축한 사람은 郭葆昌이라고 생각한다. 그는 건륭제가 특정 자기에 남긴 詠瓷詩를 『御製詩集』에서 찾아 대조하여 건륭제가 어떠한 부류의 자기를 여요자기로 감식하였는지를 확인하였다. 이러한 바탕 위에서 그는 오늘날 전세여요자기로 알려져 있는 부류의 자기를 여요자기로 파악하였다. 이와 같은 인식은 Percival David에 의해 체계적으로 정리되었다. 대다수의 연구자들은 전세여요자기로 알려져 온 실물자료들이 여요자기라는 점은 청량사여요지의 발굴로 이제 의심할 바 없는 사실이 되었다고 믿는다. 하지만 이러한 사실이 이제까지 전세여요자기로 알려진 실물자료들이 모두 진정 여요자기라는 점까지 보증하는 것은 아니다. 건륭제의 詠瓷詩와 그 밖의 문헌들에 대한 분석을 통하여 볼 때, 거기에는 여요자기뿐만 아니라 북송관요자기와 후대의 방여요자기까지 포함되어 있다고 생각한다.