• Proceedings of the Korean Information Science Society Conference
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• 2010.06c
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• pp.437-441
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• 2010

증강현실은 이미 이를 이용한 다양한 서비스들이 존재하고 있고, 최근 스마트폰이 주목받으며 덩달아 부각되고 있는 개념 중의 하나이다. 기존 증강현실을 이용한 시스템에서는 객체를 증강할 때 미리 만들어진 객체를 증강하므로 객체가 증강할 당시의 주변환경의 변화가 반영되지 않는다. 따라서 증강현실을 할 때 카메라로 들어오는 현재 배경이미지와 객체가 동떨어져 보이는 현상이 발생한다. 이는 사용자가 현실세계에 가상의 물체가 올라간 것이 어색해 보여 증강현실기반의 프로그램에 몰입하는데 방해가 된다. 본 논문에서는 증강현실기반의 시스템이 사용될 때 실시간으로 주변환경의 빛 정보를 분석하여 그 정보를 객체에 반영하는 방법을 제안한다. 다양한 주변환경 중에서도 시각적으로 많은 정보를 제공하는 빛 정보를 이용하여 보다 자연스럽게 객체의 색을 보정을 하며, 이는 실시간으로 객체에 적용된다. 이는 주변환경 정보가 다양하게 바뀌는 모바일 증강현실에서 유용하게 쓰일 것이다.

• Korean Journal of Food Science and Technology
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• v.45 no.2
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• pp.248-251
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• 2013

The purpose of this study was to investigate the inactivation effect of intense pulsed light (IPL) on Micrococcus roseus, an irradiation-resistant bacterium isolated from laver, and the commercial feasibility of this sterilization method on dried laver. The inactivation of M. roseus in cultivated plates increased with increasing light intensity and treatment time. Approximately 6.6 log CFU/mL reduction of the cell viability was achieved with IPL treatment for 3 min at 1,000 V of light intensity, tailing was not shown. In addition, the inactivation rate of M. roseus increased with increasing pulse number at same light intensity and treatment time. The killing efficiency for M. roseus increased with by decreasing the distance between the light source and the sample surface.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2000.04a
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• pp.49-51
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• 2000

오존은 온도가 높고 태양 빛이 강한 여름철에 휘발성 유기화합물(Volatile Organic Compounds)과 질소화합물(NOx)의 광 화학 반응으로 생성되는 이차적 공해물질(Secondary Air Pollutant)이다. 성층권에 존재하는 오존은 피부암을 유발시키는 강한 자외선을 차단하고 흡수하는 고마운 존재이지만, 급속한 산업발달로 다량의 공해물질유출로 인해 생성된 지표면상의 오존은 대단히 유독해서 높은 농도에서 장시간 호흡 시 호흡기관의 장애는 물론이고 치사까지 이르게 하는 것으로 알려져 있다. (중략)

• Journal of the Korean Chemical Society
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• v.55 no.3
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• pp.335-340
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• 2011

The solution properties of sodium n-dodecyl sulfate, as an anionic surfactant in the presence of a cationic watersoluble 5, 10, 15, 20-tetrakis (N-methylpyridinium-4-yl) porphyrin (TMPyP) has been comprehensively studied by means of conductometry, UV-vis and resonance light scattering (RLS) spectroscopies. The results represent the decreasing of critical micelle concentration of SDS solution due to increasing of TMPyP concentration. The stabilization of SDS micelle is due to neutralization of negative charge at the micelle surface. The presence of three different species of TMPyP in SDS solution has been unequivocally demonstrated: free porphyrin monomers, porphyrin monomers or aggregates bound to the micelles, and nonmicellar porphyrin/surfactant aggregates. Our results show SDS induced an aggregation in TMPyP. In fact two kinds of J-aggregations were observed: one of them for porphyrin monomers or aggregates bound to the micelles and the other for nonmicellar porphyrin/surfactant aggregates. However, the results represent the electrostatic interaction of TMPyP with SDS anion below the cmc.

• Korean Journal of Optics and Photonics
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• v.31 no.6
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• pp.321-327
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• 2020

We investigated the light reflection from thin films coated on substrates. Using a prism with a high refractive index as the incident medium, the phenomena of the total internal reflection (TIR) of the prism/film/substrate system and the light coupling into the optical waveguide formed by the air/film/substrate system were comprehensively studied and compared. If the refractive index of the thin film is greater than that of the substrate, within the TIR region of the substrate, sharp reflection minima occur at specific angles where the waveguide modes are excited, that can be used to accurately measure the refractive index and thickness of a thin film. On the other hand, if the refractive index of the thin film is smaller than that of the substrate, such waveguide modes do not exist. In this case, although not so distinct as a bulk medium, the TIR effect of the thin film is still observable, accompanied by an interference pattern. In this study we analyzed the overall reflection phenomena occurring from prism/film/substrate structures, to investigate the possibility of measuring the refractive index of a thin film in both cases.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.7
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• pp.36-41
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• 2018

An image intensifying device is equipment that makes weak objects visible in a dark environment, such as making nighttime bright enough to let objects be visually observed. It is possible to obtain a clear image by amplifying the light in the presence of a certain amount of weak light. However, in an extremely low-light environment, where even moonlight is not present, there is not enough light to amplify anything, and the sharpness of the screen deteriorates. In this paper, a method is proposed to improve image quality by using multiple filters and anisotropic diffusion for output noise of the image-intensifying device in extreme low-light environments. For the experiment, the output of the image-intensifying device was obtained under extremely low-light conditions, and signal processing for improving the image quality was performed. The configuration of the filters for signal processing uses anisotropic diffusion after applying a median filter and a Wiener filter for effective removal of salt-and-pepper noise and Gaussian noise, which constitute the main noise appearing in the image. Experimental results show that the improvement visually enhanced image quality. Both peak signal-to-noise ratio (PSNR) and SSIM, which are quantitative indicators, show improved values.

• The Korean Journal of Mycology
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• v.17 no.2
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• pp.99-104
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• 1989

Effects of organic compounds, photosensitizers and influx of metal ions on the light-induced mitochondrial ATP synthase in Lentinus edodes purified by stepped sucrose density gradient centrifugation were studied. In our previous work, the activation wavelength and the illumination time of mitochondrial ATP synthase were 470 nm and 15 sec, respectively. This enzyme was activated 85% by 1 mmole 2,6-dichlorophenol indopheol and inhibited by 1 mmole 2,-4-dinitrophenol, $10\;{\mu}mole$ 2-heptyl-4-hydroxyquinoline-N-oxide and $100\;{\mu}g$ oligomycin per ml of ethanol. Particularly, the enzyme was activated 414% by 10 mmole phenazine methosulfate as photosensitizer at 470 nm light. In the influx effects of $Fe^{3+}$ and $Fe^{2+}$ ion, the activity of the above enzyme increased under the optimal light condition compared with nonillumination state.

• The Journal of the Petrological Society of Korea
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• v.10 no.3
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• pp.202-211
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• 2001

Luminescence is a physical phenomenon exhibited by many non-conducting, crystalline materials, such as quartz and feldspar. Within the crystals, energy absorbed from ionising radiation frees electrons to move through the crystal lattice and some are trapped at defects in the lattice. Observable luminescence is produced by electrons, released from traps by stimulation by absorption of light, which recombine with lattice defects which act as luminescence centers - optically stimulated luminescence (OSL). In a similar way to thermoluminescence(TL) dating, controlled measurement of the OSL signal can provide a means of determining the time since the last exposure of a layer of sediment to sunlight, the age of the sediment. However, whereas in the thermoluminescence dating of sediment only part of the latent thermoluminescence signal is bleached by sunlight as the sediment is deposited and allowance must be made during the laboratory measurements for the light insensitive component, optically induced luminescence dating has the advantage of working only with light sensitive traps in the crystal. Determination of the time since deposition of Quaternary sediment samples from the OSL of quartz grains using blue light was performed. A series of experiments and recent developments relating OSL dating are described, beginning by identifying the features which make OSL signals suitable for the development of dating method. Additionally, there are suggestions as to future research for obtaining reliable ages and a comment on current best practice on procedures, with the dating results of Quaternary sediment.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.672-672
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• 2013

본 연구에서는 수열합성법을 기반으로 한 3차원 ZnO 나노구조의 합성을 통해 효율적인 양자점 감응형 태양전지로의 응용을 하고 그 특성을 평가하였다. 기존의 1차원 ZnO 나노구조의 경우 높은 전자이동도와 구조적으로 얻을 수 있는 방향성 있는 전자의 효율적인 전달을 통해 효과적인 광전극으로 많은 관심을 받아왔다. 하지만 나노파티클 기반의 필름에 비해 표면적이 크게 떨어지기 때문에 효과적인 흡광이 어렵다는 단점이 존재하여 높은 효율특성을 내지는 못하였다. 본 연구에서는 이러한 단점을 극복하면서 기존 ZnO 나노선의 장점을 극대화 하기 위해 성장시킨 ZnO 나노선 위에 추가적으로 가지를 형성하여 표면적 향상과 효과적인 전자전달 특성을 얻고자 하였다. 3차원 ZnO 나노구조는citrate 계열의 capping agent의 첨가를 통한 수열 합성법을 통해 1차원의 ZnO 나노선 위에 nanosheet 형식의 가지를 형성하였고 이는 빛의 효과적인 산란특성 및 표면적 향상을 통한 CdS, CdSe의 양자점 증착량을 증가시키는 효과를 얻을 수 있었다. 이러한 태양전지의 소자 특성은 SEM, TEM을 통한 구조 특성평가 및 DRS, J-V curve 및 IPCE를 통한 광학적 특성평가를 통해 확인하였다.

• Electronics and Telecommunications Trends
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• v.31 no.4
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• pp.1-12
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• 2016

깊이감, 시점 등의 3차원 영상정보 제공 방법에는 양안 시차에 의한 스테레오 방식, 다시점 기반의 스테레오 방식, 라이트필드 기반의 스테레오 방식, 체적 내에 실제 발광점들을 물리적으로 형성하는 체적형 방식, 빛의 간섭과 회절현상을 이용하여 실제 물체의 파면을 재현하는 홀로그래피 방식 등이 존재한다. 본고에서는, 3차원 영상기술로써 최근 이슈화되고 있는 플렌옵틱 영상기술의 개념을 다시점 영상생성 및 재초점 기능의 관점에서 소개하고, 동시에 관련 국내외 기술개발 동향을 파악하고자 한다. 또한, 플렌옵틱 영상기술의 고도화를 위한 최신 연구개발 이슈 및 응용 가능한 서비스 시나리오에 대해 탐구해 봄으로써, 향후 플렌옵틱 영상처리 기술의 발전 및 활용도를 전망해 보고자 한다.