• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.651-654
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• 2009

Novel compounds with rod and disc mesogens were synthesized and characterized. The molecular structures were confirmed by FT-IR, $^1H$-NMR spectroscopy and elemental analysis. The optical properties of these molecules were investigated by UV-vis absorption spectroscopy and photo-luminescence spectroscopy. We found that they are a novel series of blue light-emitting molecules. The absorption spectra peaks of these compounds varied from 336 nm-341 nm, while the maximum emissions centered form 410 nm-450 nm in chloroform solution. However, unexpectedly we could not found their biaxiality and mesomorphic properties by POM, conoscopy and DSC method.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.1573-1574
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• 2009

Fullerene/polystyrene nanoparticles having the average size of 300 nm ~ 1 ${\mu}m$ were prepared by emulsion polymerization in aqueous medium. Poly(vinyl pyrrolidone) and potassium persulfate were used as a dispersant and an initiator, respectively. The contents of fullerene in the nanoparticle were controlled to be from 10 to 57 wt% by varying the feed ratio, which was confirmed by IR-spectroscopy, thermogravimetric analyses, and elemental analyses. Dynamic light scattering experiments revealed the particles have a broad size distribution. Further characterizations of the nanoparticles were performed by using SEM and TEM observation. The high content of fullerene in the particles will find applications in photovoltaic and organic semiconducting area.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.694-697
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• 2007

We demonstrate the use of screen printing in the fabrication of highly efficient phosphorescent polymer organic-light-emitting devices (OLEDs) based on a green-emitting $Ir(ppy)_3$ and a host polymer PVK. We incorporate PBD in the polymer host as an electron-transporting dopant and ${\alpha}-NPD$ as a hole transporting dopant. The best screen printed single-layer device exhibits very high peak luminous efficiency of 63 cd/A at a relatively high operating voltage of 17.1 V at the luminance of $650\;cd/m^2$. We observed the highest luminance of $21,000\;Cd/m^2$ at 35V. Due to the high operating voltage, despite of the high peak luminous efficiency the peak power efficiency was found to be 12.2 lm/W at the luminance of $470\;cd/m^2$ (15.9 V).

• Bulletin of the Korean Chemical Society
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• v.30 no.12
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• pp.3025-3030
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• 2009

Novel poly(aspartic acid) derivatives conjugated with $\gamma$-amino butyric acid, GABA, moieties, and their amphiphilic analogs were synthesized and characterized. The chemical structures of these polymers were confirmed by FT-IR and $^1H$ NMR spectroscopy. Their physicochemical properties in aqueous media were characterized by electrophonetic light scattering spectrophotometry (ELS), acid-base titration, and UV-spectroscopy. In addition, the in vitro cell activity of the GABA-conjugated polymer was examined. These results indicated that GABA-conjugated poly(aspartic acid) derivatives showed cell-growth activity and nanoparticle formation of a suitable size within aqueous media. These polymers have potential application in the cosmetic and pharmaceutical fields.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2505-2510
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• 2008

A nuclear fuel test loop (after below, FTL) is installed in IR1 of an irradiation hole in HANARO for testing neutron irradiation characteristics and thermo hydraulic characteristics of a fuel loaded in a light water power reactor or a heavy water power reactor. When HANARO is normally operated, the fuel loaded in the irradiation hole has a nuclear reaction heat generated by a neutron irradiation. To remove the generated heat and to maintain an operation condition of the test fuel, a main cooling water system (MCWS) is installed in the OPS of the FTL. This paper describes the cold function test results of the MCWS. It was confirmed through the test results that the system met the design requirements under a cold operation condition.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1998.09a
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• pp.43-46
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• 1998

The effect of dopant and stoichiometry on the optical properties of LiNbO3 were studies. We prepared three samples, which are undoped, MgO doped LiNbO3 and near-stoichiometric LiNbO3 dielectric constant and transmittance in UV/VIS/IR light range were measured. The results showed that the features for high [Li]/[Nb] were similar to those for low [Li]/[Nb] but with high [Mg].

• The Bulletin of The Korean Astronomical Society
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• v.36 no.1
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• pp.31.2-31.2
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• 2011

The Vista Variable in the Via Lactea(VVV)는 European Southern Observatory(ESO) Public Survey 중 하나로 Near-IR에서 (주로 K-band)에서 관측되며 1929시간에 걸쳐 은하 중심부의 더 깊은 영역에 대한 관측을 수행할 것이다. VVV Survey를 통해 520 sq. deg에 걸친 영역에서 33개의 잘 알려진 구상성단과 350개의 산개성단을 포함한 ~109개의 별에 대한 광도 곡선을 얻을 수 있을 것으로 예상되며 이들을 분류하기 위해 자동화된 분류 체계가 필요할 것이다. 본 연구는 VVV Survey의 일환으로 보현산 천문대의 근적외선 카메라시스템 KASINICS를 이용하여 Cataclysmic Variable stars에 대한 관측을 시행하고 있다. Cataclysmic Variable stars는 초신성 폭발이나 쌍성계 중 한 쪽 별에서 다른 쪽 별로 대기가 유입되었는 경우 등에 의해 광도가 급격히 증가하는 천체로 아직 많이 연구되지 않은 적외선 파장대로 관측함으로써 적외선영역에서의 물리적 특성에 대한 분석을 하고자 한다. 본 발표에서는 보현산 천문대의 근적외선카메라시스템 KASINICS에서 관측한 결과의 일부를 소개하고자 한다.

• Journal of the Korea Institute of Military Science and Technology
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• v.10 no.3
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• pp.51-61
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• 2007

This paper concerns about the requirement analysis for night vision imaging system(NVIS), whose purpose is to intensify the available nighttime near infrared(IR) radiation sufficiently to be caught by the human eyes on a miniature green phosphor screen. The requirements for NVIS are NVIS radiance(NR), chromaticity, daylight legibility/readability, etc. The NR is a quantitative measure of night vision goggle (NVG) compatibility of a light source as viewed through goggles. The chromaticity is the quality of a color as determined by its purity and dominant wavelength. The daylight legibility/readability is the degree at which words are readable based on appearance and a measure of an instrument's ability to display incremental changes in its output value. In this paper, the requirements of NR, chromaticity, and daylight legibility/readability for Type I and Class B/C NVIS are analyzed. Also the rationale is shown with respect to those requirements.

• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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• pp.53-53
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• 2000

반도체 산업에서 유기물질의 응용에 많은 관심을 나타내고있으며, 그 응용의 예로는 발광 다이오드(light emitting diode)와 박막트랜지스터(thinfilm transistor)가 주를 이루고 있다. 이러한 유기 물질을 이용하면 소자의 제작 공정의 단순화와 제작 가격을 낮출 수 있는 이점을 기대할 수 있다. 본 연구에서는 유리 기판 위에 pentcence 다이오드를 제작하였다. 유리 기판 위에 silicon dioxide를 PECVD으로 성막하였다. 전극으로는 Ohmic contact를 이루기 위해 금(Au)을 사용하였으며 schottky contact을 이루기 위해서 알루미늄(Al), 인듐(In), 크롬(Cr), 은(Ag), 금(Au)을 각각 사용하였다. 소자의 활성 층으로는 pentcene을 가장 단순한 열 증착법으로 성막하였고, 진공도는 10-8Torr를 유지하였으며 성막 속도는 0.3 $\AA$/sec로 성막하였다. 제작된 소자들은 $\alpha$-step, I-V, C-V, AFM, IR등을 이용하여 측정, 분석하였다.

• Korean Journal of Materials Research
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• v.15 no.7
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• pp.448-452
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• 2005

This study was based on organic electroluminescence display. Especially, TPD and $\alpha-NPD$ for the hole transport materials were synthesized by Ullmann reaction. This reaction was conducted between 3­methylphenylamine, 1-naphthylamine and 4,4'-diiodobiphenyl in toluene containing CuCl catalyst and KOH base. The structural property of reaction products were analyzed by FT-IR, $^1H-NMR$ spectroscopy, and thermal stability, reactivity and PL property were analyzed by melting point, yield and emission spectrum, respectively. The photoluminescence spectra of a pure TPD and $\alpha-NPD$ were observed at approximately 416nm and 438nm respectively. In this study, it was known that the melting point, yield, PL properties of TPD and $\alpha-NPD$ were changed by substituent group of amines.