• 한국입자에어로졸학회지
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• 제6권2호
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• pp.91-103
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• 2010

Size-segregated number concentration and scattering coefficient of urban aerosols were measured using an SMPS (scanning mobility particle sizer) and a nephelometer, respectively in Seoul, Korea, during the winter season of 2003. The average number concentrations of ultrafine particles (20~100 nm) and accumulation mode particles (100~600 nm) were $2,170\;particles\;cm^{-3}$ and $1,521\;particles\;cm^{-3}$, respectively. The scattering coefficient at the wavelength of 550 nm ranged from $62.6Mm^{-1}$ to $330.1Mm^{-1}$ and average value was $163.4Mm^{-1}$. The peak concentrations of ultrafine particles and accumulation mode particles were simultaneously recorded between 6:00 and 9:00 A.M., indicating the effect of vehicle emissions which are major air pollution sources in the urban atmosphere. On average, the number concentration of ultrafine particles was 1.4 times higher than that of accumulation mode particles, although it was a little higher during the morning peak time. The variation of aerosol scattering coefficient was in good agreement with that of accumulation mode particle number concentration rather than that of ultrafine particle number concentration.g coefficient was in good agreement with that of accumulation mode particle number concentration rather than that of ultrafine particle number concentration.

• JSTS:Journal of Semiconductor Technology and Science
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• 제15권1호
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• pp.35-40
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• 2015

In this study, an n-ZnO/p-Si heterojunction diode with embedded Ag nanoparticles was fabricated to investigate the possible improvement of light trapping via the surface plasmon resonance effect for solar cell applications. The Ag nanoparticles were fabricated by the physical sputtering method. The acquired current-voltage curves and optical absorption spectra demonstrated that the application of Ag nanoparticles in the n-ZnO/p-Si interface increased the photo current, particularly in specific wavelength regions. The results indicate that the enhancement of the photo current was caused by the surface plasmon resonance effect generated by the Ag nanoparticles. In addition, minority carrier lifetime measurements showed that the recombination losses caused by the Ag nanoparticles were negligible. These results suggest that the embedding of Ag nanoparticles is a powerful method to improve the performance of n-ZnO/p-Si heterojunction solar cells.

• 대한기계학회논문집
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• 제16권10호
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• pp.1861-1868
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• 1992

본 연구에서는 발전소의 터빈 블레이드는 물방울에 의해서 부식이 발생한다는 사실은 널리 알려져 있다. 부식을 방지하기위해서 보통 12%-Cr 강으로 만들며 표면 을 고주파 유도경화법에 의해서 표면을 경화시킨다. 고주파유도 경화법은 경화층 깊 이가 마모 특성을 가장 좋게 하는 깊이보다 훨씬 깊게 경화되며, 열응력이 과대하게 생기고, 처리시간이 많이 걸리며, 표면경화 처리후 기계가공이 필요하다. 12%-Cr 강 의 레이저 표면경화를 연속파 3kw CO$_{2}$ 레이저로 실험하여 금속조직과 경도분포에 대해서 연구하여 레이저 표면경화 가능성을 고찰하였다.

• 한국항공우주학회지
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• 제45권6호
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• pp.523-530
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• 2017

높은 에너지의 레이저가 조사되면 레이저 삭마 현상을 일으키고, 결과적으로 플라즈마가 물질에 따라 특정한 파장의 빛을 방출하는 레이저 유도 파괴 분광법(LIBS, Laser-Induced Breakdown Spectroscopy)과 빛은 산란 현상에 대해 분자 간 혹은 분자 내의 회전 및 진동 운동을 측정하는 라만 분광법은 높은 정확도와 실시간 분석이 가능하다는 점, 원거리 검출이 가능하다는 장점들을 기반으로 우주 탐사 기술로써 주목을 받고 있다. 본 연구에서는 레이저 분광법을 활용하여 토양 성분의 변화에 따른 레이저 스펙트럼의 경향성을 파악하고, 이를 기반으로 2차원 화학적 분포도 실험을 진행하였다. 또한 화성(4-7 torr)과 달의 대기(<1 torr) 환경을 레이저 실험 환경 내에 구축하여 인공적인 우주 환경에서 LIBS와 라만 분광법을 활용하여 토양 성분의 변화에 따른 LIBS와 라만 분광법을 통한 계측이 가능함을 증명하였다.

• 수산해양기술연구
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• 제50권4호
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• pp.511-519
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• 2014

This study is aimed to analyze the three-dimensional underwater irradiance using an optical simulation software and to clarify the propriety and operation method under considering luminous intensity distribution of the luring lamp and penetrability in the seawater, when we use the light diffuser type 300W high powered LED and the metal halide lamp (MHL) on a coastal squid jigging vessel in the 10-ton class, simultaneously. For their attenuation characteristics of each wavelength in relation to the sea, LED lamp was to be effective in the 1.9-fold at 50 m depth and 2.1-fold at 80 m for underwater irradiance more than MHL according to the power consumption. In addition, the underwater irradiance distribution using the LED and MHL combination was rather increased even when reducing total power usage up to 20% depending on the simulation with changing the configuration and lighting angle of the lamp. These results can be utilized as an evaluation method of the operation and performance of the LED lamp according to adjusting its arrangement and lighting angle.

• 한국물환경학회지
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• 제23권3호
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• pp.319-323
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• 2007

The Advanced Oxidation Process (AOP) is being increasingly used to oxidize complex organic constituents in treated effluents from domestic wastewater treatment plants. Generally, ${NO_3}^--N$ concentrations ranges between 5 and 8 mg/L for biologically well-treated effluents. However, nitrate ions, ${NO_3}^-$, affects on oxidation as not only a well-known strong absorber of UV light below 250 nm of wavelength but also as an OH radical scavenger. The objective of this study was to evaluate the AOP systems for degradation of 2,4-DCP, and to delineate the effect of nitrate ions on UV oxidation of 2,4-DCP by conducting a bench-scale operation at various reaction times and initial concentrations of $H_2O_2$. The experimental results indicated that 2,4-DCP could be completely oxidized by $UV/H_2O_2$ process with an initial $H_2O_2$ concentration of 20 mg/L at a retention time of 1.0 min or longer. Nitrate ions did not show any adverse effect on 2,4-DCP oxidation at this high $H_2O_2$ concentration, and the practical initial $H_2O_2$ concentration and reaction time for the 80% oxidation turned out to be 5 mg/L and 1.0 min, respectively.

• 한국광학회지
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• 제21권5호
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• pp.195-199
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• 2010

본 논문에서는 광자결정 광섬유를 이용하여 1000 nm 의 광대역폭을 갖는 광신호 분배기를 구현하였다. 제작에 사용된 광자결정 광섬유의 지름은 $130{\mu}m$ 이고 6층의 공기 구멍 구조로 이루어져 있다. 광신호 분배기는 두 가닥의 광자결정 광섬유에 열을 가함과 동시에 인장력을 가해 제작하였으며 제작된 광자결정 광섬유 기반 광신호 분배기의 지름은 $23{\mu}m$ 이었다. 광신호 분배기의 제작 시 인장시키는 길이에 따라 대역폭과 bandedge가 조절되었다. 제작된 광자결정 광섬유 기반 광신호 분배기의 대역폭이 1000 nm에서 50:50의 광신호 분해 효율을 가지는 것으로 측정되었다. 광자결정 광섬유의 공기 구멍 구조의 특성으로 인해 주변온도의 변화에 영향을 받지 않는 특성을 나타낸다. Optical coherence tomography의 분해능이 광원의 대역폭에 비례하므로 광대역폭을 갖는 광자결정 광섬유 기반 광신호 분배기는 신호 추출을 위한 간섭계 구성에 핵심적으로 활용될 수 있을 것으로 사료된다.

• 한국세라믹학회지
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• 제41권10호
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• pp.766-770
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• 2004

구형 실리카 나노 콜로이드 입자를 이용하여 반사방지막을 제조하였다. 실리카 콜로이드 현탁액을 모세관 힘을 이용하여 기울어진 두 장의 유리판 사이에 저장한 후 위의 유리를 이동시켜 반사 방지막을 코팅하였다. 상판 유리의 이동속도가 빨라질수록 막의 두께는 감소하였고, 막의 두께 변화에 따라 광 투과율이 변하였다. SEM으로 관찰된 실리카 나노 입자는 최밀충진에 가깝게 유리 기판에 부착되어 있었으며, 이로부터 고체 입자와 기공을 포함하는 막의 유효 굴절율을 구하였다. 최대의 광투과율을 나타내는 파장과 유효 굴절율로 부터 계산한 막의 두께는 SEM 사진 및 profiler로 구한 값과 잘 일치하였다. $94.7\%$의 최대 광투과율을 얻었으며, 양면으로 코팅한다면 $97.4\%$의 투과율 즉 $1.3\%$의 반사율을 얻을 수 있는 것으로 나타났다.

• 한국의류산업학회지
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• 제11권6호
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• pp.953-960
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• 2009

The natural dyeing of fabrics with myrobalan extract was investigated. After dyeing of silk, cotton and rayon with myrobalan extract, the dyeability of myrobalan extract was evaluated with the conditions of concentration, temperature, time, repeat-numbers, pH, mordants variables, the changes of dyeability and surface colors by methods of mordanting and color fastness. The wavelength of maximum absorption of the colored solution from myrobalan extract appeared at 272 nm. Therefore, the substance of myrobalan extract was verified as tannin dyes. The optimum dyeing of fabrics was carried out at 30%(o.w.f) dye concentration. Silk fabrics dyed with myrobalan extract showed the highest K/S value at the temperature of $80^{\circ}C$ when it was dyed for seventy minutes, while cotton and rayon fabrics showed the highest K/S value at the temperature of $90^{\circ}C$ when they were dyed for seventy minutes and thirty minutes, respectively. Dyeing operation was carried out in acidic dyebath of pH 3. The K/S value of silk fabric was higher in pre-mordant stage than in post-mordant, while the K/S values of cotton and rayon fabrics were higher in post-mordant stage. The surface colors of dyed fabrics were different according to used mordants: Al and Cu mordanted fabrics were dyed in yellowish colors, while Fe mordanted fabric was dyed in khaki-black color. Light-fastness of the color fastness was improved in Fe-mordant. Washing-fastness was relatively good, and dry cleaning-fastness of dyed fabrics was excellent.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2011년도 춘계학술대회 초록집
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• pp.116.1-116.1
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• 2011

Materials with a combination of high electrical conductivity and optical transparency are important components of many electronic and optoelectronic devices such as liquid crystal displays, solar cells, and light emitting diodes. In this study, to fabricate a low-resistance and high optical transparent electrode film for organic photovoltaic, the following steps were performed: the design and manufacture of an electroforming stamp mold, the fabrication of thermal roll imprinted (TRI) poly-carbonate (PC) patterned films, the manufacture of high-conductivity and low-resistance Ag paste which was filled into patterned PC film using a doctor blade process and then coated with a thin film layer of conductive polymer by a spin coating process. As a result of these imprinting processes the PC films obtained a line width of $10{\pm}0.5{\mu}m$, a channel length of $500{\pm}2{\mu}m$, and a pattern depth of $7.34{\pm}0.5{\mu}m$. After the Ag paste was used to fill part of the patterned film with conductive polymer coating, the following parameters were obtained: a sheet resistance of $9.65{\Omega}$/sq, optical transparency values were 83.69 % at a wavelength of 550 nm.