• The Bulletin of The Korean Astronomical Society
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• v.30 no.1
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• pp.66.1-66.1
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• 2005

• Journal of The Korean Astronomical Society
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• v.38 no.3
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• pp.357-363
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• 2005

A deep stellar analysis is introduced for the poorly studied open cluster NGC 2509. The Near-IR database of the digital Two Micron All Sky Survey (2MASS) has been used to re-estimate and refine the fundamental parameters of the cluster, i.e. age, reddening, distance, and diameter. As well as, luminosity function, mass function, total mass, relaxation time, and mass segregation of NGC 2509 have been estimated here for the first time..

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.20-23
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• 2009

The efficacy improvement issues in a unit discharge cell have been approached from the structural considerations. The tested cell designs include (a) a coplanar type with annular auxiliary electrode buried in barrier ribs, (b) a coplanar type with split auxiliary electrodes also burred in barrier ribs and (c) a coaxial type with a floating electrode stacked on the base electrode. From spatiotemporally resolved optical images of near-IR emission taken by a gated-ICCD camera and relative VUV emission intensity estimated by laser absorption spectroscopy, the differences in the discharge and light emission performances of those three cell types have been compared and discussed.

• Publications of The Korean Astronomical Society
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• v.25 no.4
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• pp.107-112
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• 2010

By joining the Giant Magellan Telescope (GMT) project, Korean astronomers will get 10% of the GMT time, starting in the late 2010s. To prepare the GMT era, it is important to evaluate the current observational research activities. We surveyed the research programs performed by domestic astronomers during 2007A - 2010A period, using optical/near - IR telescopes with a medium to large aperture mirror (larger than 4 m). We describe the method and criteria of the survey, and present the results of the analysis based on the collected data.

• 한국지구과학회:학술대회논문집
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• 2005.02a
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• pp.174-175
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• 2005

• Journal of Korean Neurosurgical Society
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• v.57 no.4
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• pp.283-288
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• 2015

Objective : This study aims to visualize the subjective symptoms before and after the treatment of whiplash injury using infrared (IR) thermography. Methods : IR thermography was performed for 42 patients who were diagnosed with whiplash injury. There were 19 male and 23 female patients. The mean age was 43.12 years. Thermal differences (${\Delta}T$) in the neck and shoulder and changes in the thermal differences (${\Delta}dT$) before and after treatment were analyzed. Pain after injury was evaluated using visual analogue scale (VAS) before and after treatment (${\Delta}VAS$). The correlations between ${\Delta}dT$ and ${\Delta}VAS$ results before and after the treatment were examined. We used Digital Infrared Thermal Imaging equipment of Dorex company for IR thermography. Results : The skin temperature of the neck and shoulder immediately after injury showed $1-2^{\circ}C$ hyperthermia than normal. After two weeks, the skin temperature was normal range. ${\Delta}T$ after immediately injuy was higher than normal value, but it was gradually near the normal value after two weeks. ${\Delta}dT$ before and after treatment were statistically significant (p<0.05). VAS of the neck and shoulder significantly reduced after 2 week (p=0.001). Also, there was significant correlation between ${\Delta}dT$ and reduced ${\Delta}VAS$ (the neck; r=0.412, p<0.007) (the shoulder; r=0.648, p<0.000). Conclusion : The skin temperature of sites with whiplash injury is immediately hyperthermia and gradually decreased after two weeks, finally it got close to normal temperature. These were highly correlated with reduced VAS. IR thermography can be a reliable tool to visualize the symptoms of whiplash injury and the effectiveness of treatment in clinical settings.

• Publications of The Korean Astronomical Society
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• v.27 no.4
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• pp.347-352
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• 2012

Understanding infrared (IR) luminosity is fundamental to understanding the cosmic star formation history and AGN evolution, since their most intense stages are often obscured by dust. Japanese infrared satellite, AKARI, provided unique data sets to probe this both at low and high redshifts. The AKARI performed an all sky survey in 6 IR bands (9, 18, 65, 90, 140, and $160{\mu}m$) with 3-10 times better sensitivity than IRAS, covering the crucial far-IR wavelengths across the peak of the dust emission. Combined with a better spatial resolution, AKARI can measure the total infrared luminosity ($L_{TIR}$) of individual galaxies much more precisely, and thus, the total infrared luminosity density of the local Universe. In the AKARI NEP deep field, we construct restframe $8{\mu}m$, $12{\mu}m$, and total infrared (TIR) luminosity functions (LFs) at 0.15 < z < 2.2 using 4,128 infrared sources. A continuous filter coverage in the mid-IR wavelength (2.4, 3.2, 4.1, 7, 9, 11, 15, 18, and $24{\mu}m$) by the AKARI satellite allows us to estimate restframe $8{\mu}m$ and $12{\mu}m$ luminosities without using a large extrapolation based on a SED fit, which was the largest uncertainty in previous work. By combining these two results, we reveal dust-hidden cosmic star formation history and AGN evolution from z = 0 to z = 2.2, all probed by the AKARI satellite.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.225-225
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• 2016

PHOLED devices which have the structure of ITO/HAT-CN(5nm)/NPB(50nm)/EML(47nm)/TPBi(10nm)/Alq3(20nm)/LiF(0.8nm)/Al(100nm) are fabricated to investigate the diffusion length of the triplet exciton by using double-quantum-well(DQE) EML structure. To fabricate DQW structures, Ir(ppy)3(2% wt) and Ir(btp)2(8% wt) are used as green and red emission zones, respectively. In DQW structured EML, as shown in Fig. 1, 1nm thick layers of green and red emission zones are located middle of the EML, and the distance between these wells(x) is changed from 0nm to 10nm. As shown in Fig. 2, the emission spectra from DQW PHOLED devices are changed with different x. The intensity of the green emission(520nm) is decreased when x is decreased, and it goes to near zero when x=0nm. This behavior can be identified as the diffusion of the triplet excitons from Ir(ppy)3 to Ir(btp)2 by the Dexter energy transfer(DET). From the external quantum efficiency(EQE) of the red emission, as shown in Fig. 3, the diffusion length of the triplet excitons can be determined by the equation of DET rate, R=A Exp(-2RDA/L), where RDA is donor-acceptor distance and L is the sum of the van der Wals radii. As a result, the measured data of the red EQEs with different x are identified to theoretical result from the equation of DET rate(Fig. 4). From this results, we could confirm that the diffusion length of the triplet excitons can be determined by using DQW structure and this method is very useful to investigate the behavior of the excitons in PHOLEDs.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.251.2-251.2
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• 2010

Plant biomass has been proposed to be an alternative source for petroleum-based chemical compounds. Especially, phenolic chemical compounds can be obtained from lignin by chemical depolymerization processes because lignin consists of complex aromatic polymer such as trans-p-coumaryl, coniferyl and sinapyl alcohols, etc. Phenolic chemical compounds from lignin were usually produced in super critical water. However, we applied Near-critical water (NCW) system because NCW is known as a good solvent for lignin depolymerization. Organic matter like lignin can be solved in NCW system and the system has a unique acid-base property without conventional non-eco-friendly chemicals such as sulfuric acid and sodium hydroxide. In this work, we tried to optimize the NCW depolymerization system by adjusting the processing variables such as reaction time, temperature and pressure. Moreover, the amount of additional phenol was optimized by changing the molar ratio between water and phenol. Phenol was used as capping agent to prevent re-polymerization of active fragment such as formaldehyde. Alkali-lignin was used as a starting material and characterized by a Solid State 13C-NMR, FT-IR and EA (Elemental Analysis). GC-MS analysis confirmed that o-cresol, p-cresol, anisole and 4-hydroxyphathalic acid were the main product and they were quantitatively analyzed by HPLC.

• Bulletin of the Korean Space Science Society
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• 2009.10a
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• pp.29.4-30
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• 2009

Extra-tidal feature of the globular clusters such as tidal tails and halos can be a crucial evidence of the merging scenario of the Galaxy formation in the dynamical point of view. To search for such an extra-tidal feature of globular clusters located in the Galactic bulge(RGC<3kpc), we obtained wide-field near-infrared JHKs images of 6 metal-poor ([Fe/H]<-1.0) clusters and 3 metal-rich ([Fe/H]>-1.0) clusters. Observations were carried out using IRSF 1.4m telescope and SIRIUS near-infrared camera, during 2006~2007. The obtained images have a total maximum field-of-view of ~ $21'\times 21'$. To select clusters' member stars and minimize the field star contaminations, we applied CMD masking algorithm. Smoothed surface density contour maps with selected stars for each cluster show overdensity features around the tidal radius and beyond. Also, radial surface density profiles within the tidal radius of the clusters show an overdensity feature as a change of slope of the radial profile. The results add further observational constraints of the formation of the Galactic bulge.