• Proceedings of the Optical Society of Korea Conference
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• 1990.02a
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• pp.172-176
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• 1990

A high resolution picosecond absorption kinetic spectrometer utilizing dye emission and a streak camera is presented and compared with other methods of picosecond transient absorption measurements. Typical transient absorption and bleach recovery kinetics measured with this spectrometer are shown. Single wavelength transient absorption or ground state bleach recovery kinetics are determined on the basis of a single laser shot, so that the samples are relatively free frm decomposition by irradiation. Excellent kinetics may be obtained from the near UV to the near IR and are not subject to interference from luminescence of samples. The sensitivity of this spectrometer is very high and it is reasonably easy and convenient to set up and use.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.7
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• pp.1380-1385
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• 2009

This paper was studied about the aging judgment method by ultraviolet rays image to happen in electric power equipment using ultraviolet rays camera. We established the aging judgment method as follows; 20% within of risk factor of insulation state of electrical facility that ultraviolet rays image does not show is "good or recognition". 30$^{\sim}$50% within of risk factor is "check", 50$^{\sim}$60% within of risk factor is "inspection" and 60% above of risk factor is "replacement". This method will be utilized for the inspection about electrical facilities.

• Journal of the Korean Society of Industry Convergence
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• v.22 no.5
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• pp.467-473
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• 2019

In this study, approached to improve durability of the multi-functional nano-pattern fabricated on the curved lens surface using nanoimprint lithography (NIL) was proposed, and the effects of the proposed methods on functionality after wear test were examined. To improve the mechanical property of ultraviolet(UV)-curable resin, UV-NIL was conducted at the elevated temperature around $60^{\circ}C$. In addition, micro/nano hierarchical structures was fabricated on the lens surface with a durable film mold. Analysis on the worn surfaces of nano-hole pattern and hierarchical structures and measurements on the static water contact angle and critical water volume for roll-off indicated that the UV curing process with elevated temperature is effective to maintain wettability by increasing hardness of resin. Also, it was found that the micro-scale pattern is effective to protect nano-pattern from damage during wear test.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.209.1-209.1
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• 2012

TUS(Tracking Ultraviolet Setup)는 5x1019 eV 이상의 초고에너지 우주선의 스펙트럼과 그 기원, 그리고 고층대기 극한방전 현상(TLE) 관측을 위한 우주망원경이다. 위성 Lomonosov의 탑재체로 2013년에 발사예정에 있으며 지구로부터 550km 상공에서 지구를 돌며 3년 이상 임무를 수행할 예정이다. TUS는 크게 반사경과 Detector Module 두 부분으로 나뉜다. 7개의 육각형 프레넬 거울을 이용한 $2m^2$ 크기의 반사경과 256개의 PMT(Photo Multiplier Tube)로 구성된 Detector Module을 이용하여 지구 대기에서 초고에너지 우주선에 의해 발생하는 UV fluorescence와 Cherenkov light를 관측한다. TUS Detector Module의 한 부분인 Pinhole Camera는 본 연구단의 기술로 직접 개발한 탑재체로서 TUS 반사경을 통하지 않고 두개의 $8{\times}8$ 어레이 MAPMT (Multi Anode PMT)가 직접 지구를 바라보며 고층대기 극한방전 현상을 관측한다. Pinhole camera는 TUS의 시야각을 포괄하는 넓은 시야각을 가지고 있으며 빠른 트리거 시스템으로 고층대기 극한 방전 현상을 관측하며, 이 방전현상과 TUS가 관측하는 초고에너지 우주선과의 상관 관계를 연구한다. 현재 TUS 및 Pinhole Camera는 러시아에서 조립되어 우주환경 인증 시험 및 인터페이스 테스트가 진행되고 있다. 본 발표에서는 TUS와 Pinhole Camera를 소개하고 현재까지의 진행상황 및 테스트 결과에 대해 보고하고자 한다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.4
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• pp.726-732
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• 2007

We fabricated UV absorption functional $10{\sim}50nm-TiO_{2-x}/quartz$ structures layer using ALD (atomic layer deposition) method. We deposited $10nm-TiO_{2-x}$ layer on quartz substrate using ALD, and film thickness was determined by an ellipsometer. The others specimen thickness was controlled by ALD time lineally. We characterized controlling phase UV and visible optical property using an X-ray difractometer, a UV-VIS-IR spectrometer and a digital camera. $ALD-TiO_{2-x}$ layers were non-stoichiometric $TiO_{2-x}$ form and amorphous phases comparing with bulk $TiO_2$. While the conventional bulk $TiO_2$ had band gap of $3.0{\sim}3.2eV$ resulting in absorption edges at 380 nm and 415 nm, $ALD-TiO_{2-x}$ layers showed absorption edges at 197 nm and 250 nm. Therefore, our nano-thick $ALD-TiO_{2-x}$ was able to absorb shorter UV region and showed excellent transmittance in visible region. Our result implies that our newly proposed nano-thick $TiO_{2-x}$ using ALD process may improve transmittance in visible rays and be able to absorb shorter UV light effectively.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.182.2-182.2
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• 2015

최근 학계나 산업계에서 투명 전자 소자에 대하여 활발한 연구가 진행되면서, 투명 전 도성 산화물(TCO: transparent conductive oxide)에 대한 관심이 높아지고 있다. 대표적인 TCO 물질인 Indium Tin Oxide (ITO)는 가시 광 영역에서의 높은 투과 및 높은 도전성을 가져 전압을 인가하면 발열이 가능하므로 이를 투명 면상 발열체에 적용시키는 연구가 활발히 진행되고 있다. 하지만, ITO는 발열 테스트 결과 온도가 상승함에 따라 발열이 일부분에 집중되는 현상이 있으며, 전도성을 높이기 위하여 추가공정이 필요하다. 또한, 글라스의 곡면 부분에서 ITO를 사용하면 유연성이 부족하므로 크랙이 발생한다는 단점이 있다. 따라서, 최근 Silver nanowire (AgNW), Single-walled Carbon nanotube (SWCNT), ITO를 기반으로 한 AgNW에 ITO를 증착 하거나 SWCNT를 코팅하여 우수한 전기적, 광학적 특성을 지닌 하이브리드 전극이 투명 면상 발열체 재료로서 사용되고 있다. 하지만 대체된 재료들도 다양한 문제점을 가지고 있다. 예를 들어 고온에서 발열을 유지하지 못하고 끊어지거나 가시광영역의 투과율이 낮은 점 등이 있다. 이런 다양한 문제점들을 보완 할 수 있는 새로운 투명 면상 발열체에 적용한 연구가 요구되고 있다. 본 연구에서는 GZO/Ag/GZO 하이브리드 구조의 투명 면상 발열체를 제작하여 전기적, 광학적 특성을 비교하고 발열량, 온도 균일 성, 발열 유지 안정도를 확인하였다. 본 연구에서는 $50{\times}50mm$ 크기의 Non-alkali glass (삼성코닝 E2000) 기판 상에 DC마그네트론 스퍼터링 공정을 이용하여 상온에서 GZO, Ag, GZO 박막을 연속적으로 증착 하여 다층구조의 하이브리드형 투명 면상 발열체를 제조하였다. 박막 증착 파워는 DC (Ag) power 50 W, RF (GZO) power 200 W로 하였으며 GZO박막두께는 45 nm로 고정 시키고 Ag박막 두께는 5~20 nm로 변화를 주었다. 증착원은 3인치 GZO 세라믹 타깃 (2.27 wt. % Ga2O3) 과 Ag 금속 타깃 (순도 99.99%)을 사용하였으며, Ar을 40 sccm 주입 후 Working pressure는 고 순도 Ar을 사용하여 1.0 Pa로 고정하며 10분간 Pre-sputtering을하고 증착을 진행하였다. 앞선 실험을 통해 증착한 박막의 전기적, 광학적 특성은 각각 Hall-effect measurements system (ECOPIA, HMS3000), UV-Vis spectrophotometer (UV-1800, Shimadzu)를 사용해 측정 되었으며, 하이브리드 표면의 구조 및 형상은 FESEM으로 관찰하였다. 또한 표면온도 측정기infrared camera (IR camera)를 이용하여 4~12 V/cm의 전압을 인가 시 시간에 따른 투명 면상 발열체의 표면 온도변화를 관찰하였다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.4
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• pp.147-152
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• 2008

This paper describes the breakdown poperties of porcelain and polymer insulators using the UV camera. The experiment was carried out using condition of voltage at the KS C IEC 60060-1(2006). As these results, corona discharge in porcelain insulator was generated the weakness point of insulator union. And the corona discharge of polymer insulator happened in union of power source. Also, we could confirm easily weakness part of these insulators by ultraviolet image through the corona discharge. Besides, in the comparison with the exciting technique of ultrasonic detection, it confirmed that deterioration steps are corrected. These steps are possible to judge the deterioration of power facilities through reliable date. Hereafter, this study as the diagnostic technology suitable for the sites is used.

• Analytical Science and Technology
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• v.36 no.3
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• pp.121-127
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• 2023

The detection of blood at a crime scene is an important process for identification and case reconstruction. However, blood may be difficult to observe with the naked eye on dark or multi-colored surfaces. Acidic hydrogen peroxide (AHP) is a recently reported blood enhancement reagent that can enhance blood with high sensitivity by increasing the exposure time of the camera. However, it has never been compared to previously known techniques on dark or multi-colored surfaces. For this purpose, the method of observation/photographing (UV and IR photography), alginate casting, leuco rhodamine 6G (LR6G), and AHP were applied to bloody impression on dark or multi-colored surfaces and the results were compared. As a result, blood treated with AHP had a higher contrast to the surfaces than UV and IR photography, and it was applicable on all surfaces, opposed to alginate casting. In addition, AHP successfully enhanced blood on dark or multi-colored surfaces, similar to LR6G.

• Journal of ILASS-Korea
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• v.3 no.4
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• pp.35-42
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• 1998

Laser Raman scattering method has been applied to measure equivalence ratio of methane/air and propane/air mixture in constant volume combustion chamber. We used high power KrF excimer laser$(\lambda=248nm)$ and a high gain ICCD camera to capture low intensity Raman signal. Raman shifts and Ram cross-sections of $H_2,\;O_2,\;N_2,\;CO_2,\;CH_4\;and\;C_3H_8$ were measured precisely. Our results showed an excellent agreement with other groups. Mole fraction measurement of $O_2\;and\;N_2$ from air showed that $O_2\;:\;N_2$ = 0.206 : 0.794. We used constant volume combustion chamber and gas injector which is operated at $5\sim10barg$. Methane and propane are used as a fuel. 50 Raman signal are obtained and ensemble averaged for measurement of equivalence ratio. Our measured results showed that the equivalence ratio of fuel/air mixture is reasonable at ${\pm}5%$ error range.

• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.2
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• pp.60-68
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• 1997

Rayleigh Scattering Cross Sections($\sigma$i) of various gases and the temperature distributions of premixes C3H8/O2 flame are measured by high power KrF(248nm) Exci- mer laser and ICCD camera. Results show that $\sigma$i of O2 and Propane(C3H8) gases agree well in the 5% error range, but of H2 has the more or less difference from the calcul- ated value by other groups. This is attributed to the low RS signal of H2 to Nosie level(S/N ratio). The temperature distributions of flame range out between 300K in the air and about 2000K in the burned area. In this temperature range, out system has the about 250K temperature resolution. Because low RS signals in the reaction area with high temperature are affected highly by noises, temperature uncertainty of this area is relatively high to another part of flame. Experimental results show that UV Rayleigh Scattering can be used for the measurement of mixing ratio of mixed gases and the temperature distributions of flame. Especially, this technique can be applied for the measurement of the mixing ratio of air/fuel before the ignition and the flame structure after the ignition inside the Engine.