• Proceedings of the Materials Research Society of Korea Conference
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• 2003.03a
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• pp.218-218
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• 2003

21세기 정보기반사회에서는 정보처리량의 증가로 인한 대용량 정보 교환을 위하여 신호처리의 고속화/광대역화가 요구되어진다. 완전 광통신망의 구축에 의한 대용량의 광통신을 위해서는 고속이며, 집적화가 가능한 저가의 광전자 소자 개발이 필요하다. 광전자 소자 중 전기-광학 변조 효과를 이용한 광소자의 구현을 위한 소재로서 극성 배향된 비선형 광학 유기고분자 소재는 가공성이 뛰어나 원하는 형태의 광도파로로 제조할 수 있다는 장점에 많은 연구가 진행되고 있다. 그러나 아직 전기광학계수의 향상과 더불어 유기고분자가 가지고 있는 열 및 광화학적 안정성이 낮은 기본적인 문제점과 폴링(poling)에 의해 배향된 극성이 시간에 따라 완화되는 문제의 해결이 요구되고 있다. 이러한 문제점 해결을 위한 기초 연구로 유기물을 졸-겔 매트릭스에 나노 사이즈로 분산하는 방법으로 유기물의 내화학적 안정성을 향상하고자 시도하였다. 잘 알려져 있는 바와 같이 유/무기 하이브리드 졸-겔 재료는 광 투광성이 우수하고 저온에서의 재료 합성과 저가 공정이 가능하여 광기능성 유기물의 호스트(host) 재료로 많이 연구되고 있다. 본 연구에서는 MTMS(methyltrimethoxysilane)과 TEOS (tetra-ethoxyorthosilicate)를 0-100 mol%로 혼합하고 가수분해하는 방법으로 친수성/친유성 특성을 제어하여, 분산되는 유기물의 사이즈를 조정하였다. 각 실험 조건에 따른 유기물 분산체의 크기를 SEM 및 TEM으로 관찰하였으며, 나노 사이즈로 분산된 유/무기 졸-겔 코팅막의 광학적 특성을 프리즘 커플러를 이용하여 조사하였다.

• Journal of Plant Biology
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• v.36 no.4
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• pp.383-389
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• 1993

The effects of light and $CO_2$ on the electrophysiological characteristics of guard cells in the intact leaf and in the detached epidermis have been investigated. Guard cells in intact leaves showed the membrane hyperpolarization in response to light. The biggest induced change of the membrane potential difference (PD) in the guard cells of the intact leaf was 13 m V by light and 42 mV by $CO_2$ in Commelina communis. Similar results were obtained with Tradescantia virginiana. However, there were no changes of membrane PD in detached epidermis. In order to determine the influence of the mesophyll on the changes of membrane PD, infiltration of the mesophyll cells with photosynthetic inhibitors was performed. In CCCP infiltrated leaf discs the guard cell membrane was depolarized slightly by red-light and hyperpolarized by $CO_2$, but in leaf discs infiltrated with DCCD and DCMU the guard cell membrane was hyperpolrized by both red-light and $CO_2$ as the control leaf discs. In azide infiltrated leaf discs the guard cell membrane showed no response to light and there was a much reduced membrane hyperpolarization by $CO_2$ compared to other responses. It was likely that azide caused leaf damage and the activity of cell metabolism was decreased greatly, resulting in small membrane PD changes by $CO_2$ and no changes by redlight. Therefore, it can be suggested that red light was sensed by the mesophyll and the light induced guard cell membrane hyperpolarization was related to energy produced by cyclic-photophosphorylation, but ${CO_2}-induced$ guard cell membrane hyperpolarization was not related to photosynthesis. Alkalisation of the vacuole was observed when the intact leaf was exposed to $CO_2$, indicating that membrane hyperpolarization was mainly the result of proton efflux.efflux.

• Electronics and Telecommunications Trends
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• v.25 no.6
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• pp.92-109
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• 2010

패킷-광 통합 전달망 기술은 지능형 패킷 전달 계층과 대용량 광 전달 계층을 통합하고 이를 단일 체계로 제에/관리하여 광대역 고신뢰의 패킷-광 통합 전달 경로를 효율적으로 제공하는 기술로서, 이를 통해 다양한 멀티미디어 서비스를 효과적으로 수용할 수 있는 패킷-광 통합 전달망 구축이 가능해진다. 본 고에서는 패킷-광 통합 전달망 기술의 표준화 동향, 개발 동향 및 상용 제품의 주요 특정들을 살펴보고자 한다.

• Journal of Plant Biotechnology
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• v.46 no.4
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• pp.291-296
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• 2019

This study was conducted to determine the effect of a light-emitting diode (LED) on in vitro shoot growth and rooting in teak (Tectona grandis L.). In the experiments with apical bud explants, the greatest shoot elongation (3.2 cm) occurred when they were cultured on DKW medium under 50% blue and 50% red LED mixture (BR), whereas no differences in growth were observed in different light sources (florescent light [F] or BR) or media (MS or DKW). The highest number of shoot multiplication (2.4/explant) or elongation (4.94 cm) was achieved with 0.5 or 1.0 mg/L 6-Benzyladenine (BA) treatment under BR. In addition, the best rooting rate (93.8%) or root length (1.3 cm) was recorded with 0.5 mg/L indole-3-butyric acid (IBA) treatment under BR, and the highest root induction (3.1/explant) was observed in 0.2 mg/L IBA under BR. The in vitro rooted plantlets were hardened and survived well on soil.

• Journal of Life Science
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• v.25 no.3
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• pp.269-275
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• 2015

Collagen peptides, which are found at high concentrations in the human body, are present in animal bones and the skin of marine organisms, namely, fish scales. Collagen is the most abundant structural protein of various connective tissues in animals. Furthermore, it is widely used in biomedical material, pharmaceutical, cosmetic, food, and leather industries. Peptides extracted from scales of various fish protect against ultraviolet B (UVB)-induced skin damage and photo-aging. However, the protective effects of collagen peptides derived from the scales of Branchiostegus japonicus against UVB exposure are unclear. This study investigated the effects of peptides larger than 1 kDa (high-molecular weight peptides [HMP]) and smaller than 1 kDa (low-molecular weight peptides [LMP]), derived from extracts of B. japonicus scales, against UVB-induced skin damage and photo-aging. These peptides scavenged 1,1-diphenyl-2-picrylhydrazyl radicals in a dose-dependent manner. In UVB-exposed HaCaT human keratinocytes, LMP inhibited 8-isoprostane generation, a marker of cellular lipid peroxidation. The peptides also suppressed the UVB-induced increase in tyrosinase activity and melanin content in B16F10 mouse melanoma cells. In addition, the LMP and HMP treatment suppressed UVB-induced elastase and matrix metalloproteinase-1 activities in the HaCaT cells. These results indicate that peptides derived from B. japonicus scales have antioxidant, antiphoto-aging, and skin-whitening effects.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.10a
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• pp.856-859
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• 2003

본 논문에서는 이동통신 환경 하에서의 광통신 접목기술을 사용하여 광PCS 시스템의 성능을 컴퓨터 시뮬레이션을 사용하여 수치적으로 분석하였다. 광섬유가 제공할 수 있는 막대한 대역폭을 효율적으로 활용하기 위하여, 광 수신기는 보다 많은 정보를 송신할 수 있도록 충분히 빠른 변조 속도를 요구하며, 광수신기는 수신되는 고속의 광 신호를 전기적 신호로 충분히 검파시킬 수 있는 능력을 가져야한다. 수십 기가 bps 이상의 초고속광통신시스템을 구현하기 위해서는 광섬유의 분산 효과에 의한 펄스촉의 증가를 억제할 수 있는 기술이 요구된다. 따라서 본 논문에서는 광섬유의 chirping 의 영향을 고려하여 시스템의 성능을 직접 변조 방식을 사용하여 수치적 시뮬레이션을 통하여 신호 대잡음 비를 유도하여 시스템의 성능을 비교 분석 하였다.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.39 no.2
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• pp.128-133
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• 2003

Stimulus effects of strobe light on jack mackerel Trachurus japonicus were studied by measuring the heart rate change according to the different strobe light intensity of 5~75 lx$\cdot$s. Heart rate was observed for 60 min: 10 min before, 30 min during and 20 min after the strobe light stimulus. The measurement of heart rate was repeated three times at 2 hour intervals. The results showed that the heart rate increased during stimulus but temporarily decreased immediately after ending of stimulus. The heart rate changes in both during and after stimulus were decreased with reducing light intensities. The heart rate change according to the repeated experiment was not remarkably different under the lower light intensity

• Journal of Life Science
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• v.33 no.5
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• pp.414-421
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• 2023

Cnidium japonicum (C. japonicum) is a type of halophyte that inhabits soil of a high salinity, and according to previous studies, it is known to have antitumor effects. However, the skin's protective effect, particularly against UVB irradiation, has not been revealed. In this study, C. japonicum crude extract was studied to determine its effect on damage to human keratinocytes (HaCaT) induced by UVB irradiation, and ROS assays were performed, the results of which showed that C. japonicum crude extract affects UVB-induced photoaging damage in human keratinocytes. To examine inhibitory effects against the expressions of MMPs, RT-PCR and Western blot assay were performed by treating the crude extract at concentrations of 10, 50, and 100 ㎍/ml by irradiating UVB at 15 mJ/cm². As a result, it was confirmed that the mRNA and protein expression levels of MMP-1, MMP-3, and MMP-9 decreased in the group treated with C. japonicum crude extract, which also effectively regulated the antioxidant defense mechanism pathway by activating JNK, ERK, and p38. In conclusion, the current study suggested the possibility that C. japonicum could be used as a raw material for anti-photoaging cosmeceuticals in the future.

• Proceedings of the Optical Society of Korea Conference
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• 2009.10a
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• pp.229-230
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• 2009

• Proceedings of the KIPE Conference
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• 2010.11a
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• pp.50-51
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• 2010

저탄소전력시스템에서 자연에너지의 유효이용과 전력의 안정공급이 요구되고 있다. 저탄소 전력시스템을 조성하기 위한 방법은 다양하나 그 중에서 발전 시에 온실효과 가스를 배출하지 않는 원자력이나 태양광발전 등 저탄소 전력시스템의 비율을 높이는 것이다.