• The Bulletin of The Korean Astronomical Society
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• v.41 no.1
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• pp.73.1-73.1
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• 2016

We present preliminary results of the submillimeter continuum observations of 14 Planck Galactic Cold Clumps (PGCCs), located in the ${\lambda}$ Orionis Complex. This region is the nearest large HII region, which is an ideal site for a study of the stellar feedback to its surroundings. We observed 14 PGCCs with JCMT/SCUBA-2 and used J=1-0 transitions of CO isotopologues from the PMO mapping observation. Several sub-clumps toward three PGCCs were detected at $850{\mu}m$. In order to examine whether these clumps can be candidates for pre-stellar cores, we compared each clump mass calculated from the $850{\mu}m$ continuum map to its Virial mass and Jeans mass calculated from the $^{12}CO$ and $C^{18}O$ (1-0) spectra, respectively. All clumps have masses smaller than their Virial and Jeans masses, indicating that none of them are gravitational bound and thus in the pre-stellar core stage. Also, the CO depletion factor, which has been derived from the dust continuum and the $C^{18}O$(1-0) line and can be an indicator of core evolution, toward the clumps is in the range of 1 to 5, suggesting that they are not very evolved dense pre-stellar cores. In addition, within individual PGCCs, we found clear gradients of velocity (${\sim}1km\;s^{-1}\;pc^{-1}$) and temperature (${\sim}10K\;pc^{-1}$) in the $^{13}CO$ (1-0) first moment map and the $^{12}CO$(1-0) excitation temperature map, respectively. This can be attributed to the compression and external heating by the HII region, which may prevent clumps from forming gravitationally bound structures and eventually disperse clumps. These results could be a hint about the negative effect of stellar feedback on core formation.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.1
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• pp.43.1-43.1
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• 2015

We have discovered an unexplored population of galaxies featuring weak broad-line regions (BLRs) at z < 0.2 from detailed analysis of galaxy spectra in the Sloan Digital Sky Survey Data Release 7. These objects predominantly show a stellar continuum but also a broad $H{\alpha}$ emission line, indicating the presence of a low-luminosity active galactic nucleus (AGN) oriented so that we are viewing the central engine directly without significant obscuration. These accreting black holes have previously eluded detection due to their weak nature. The new BLR AGNs we found increased the number of known type 1 AGNs by 49%. Some of these new BLR AGNs were detected at the Chandra X-ray Observatory, and their X-ray properties confirm that they are indeed type 1 AGN. Based on our new and more complete catalogue of type 1 AGNs, we derived the type 1 fraction of AGNs as a function of [OIII] ${\lambda}5007$ emission luminosity and explored the possible dilution effect on the obscured AGN due to star-formation. The new type 1 AGN fraction shows much more complex behavior with respect to black hole mass and bolometric luminosity than suggested by the existing receding torus model. The type 1 AGN fraction is sensitive to both of these factors, and there seems to be a sweet spot (ridge) in the diagram of black hole mass and bolometric luminosity. Furthermore, we present a hint that the Eddington ratio plays a role in determining the opening angles. This work is submitted to ApJS.

• Journal of Animal Science and Technology
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• v.62 no.3
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• pp.293-305
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• 2020

The difference in the breeding programs and population history may have diversely shaped the genomes of Korean native cattle breeds. In the absence of phenotypic data, comparisons of breeds that have been subjected to different selective pressures can aid to identify genomic regions and genes controlling qualitative and complex traits. In this study to decipher genetic variation and identify evidence of divergent selection, 3 Korean cattle breeds were genotyped using the recently developed high-density GeneSeek Genomic Profiler F250 (GGP-F250) array. The three Korean cattle breeds clustered according to their coat color phenotypes and breeding programs. The Heugu breed reliably showed smaller effective population size at all generations considered. Across the autosomal chromosomes, 113 and 83 annotated genes were identified from Hanwoo-Chikso and Hanwoo-Heugu comparisons, respectively of which 16 genes were shared between the two pairwise comparisons. The most important signals of selection were detected on bovine chromosomes 14 (24.39-25.13 Mb) and 18 (13.34-15.07 Mb), containing genes related to body size, and coat color (XKR4, LYN, PLAG1, SDR16C5, TMEM68, CDH15, MC1R, and GALNS). Some of the candidate genes are also associated with meat quality traits (ACSF3, EIF2B1, BANP, APCDD1, and GALM) and harbor quantitative trait locus (QTL) for beef production traits. Further functional analysis revealed that the candidate genes (DBI, ACSF3, HINT2, GBA2, AGPAT5, SCAP, ELP6, APOB, and RBL1) were involved in gene ontology (GO) terms relevant to meat quality including fatty acid oxidation, biosynthesis, and lipid storage. Candidate genes previously known to affect beef production and quality traits could be used in the beef cattle selection strategies.

• The Bulletin of The Korean Astronomical Society
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• v.45 no.1
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• pp.30.1-30.1
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• 2020

The ASKAP-EMU survey is a deep wide-field radio continuum survey designed to cover the entire southern sky and a significant fraction of the northern sky up to +30°. Here, we report a discovery of a radio relic in the merging cluster SPT-CL J2023-5535 at z=0.23 from the ASKAP-EMU pilot 300 square degree survey (800-1088 MHz). The deep high-resolution data reveal a ~2 Mpc-scale radio halo elongated in the east-west direction, coincident with the intracluster gas. The radio relic is located at the western edge of this radio halo stretched ~0.5 Mpc in the north-south orientation. The integrated spectral index of the radio relic within the narrow bandwidth is α1088MHz800MHz = -0.76 ± 0.06. Our weak-lensing analysis shows that the system is massive (M200 = 1.04 ± 0.36 × 1015M⊙) and composed of at least three subclusters. We suggest a scenario, wherein the radio features arise from the collision between the eastern and middle subclusters. Furthermore, the direct link between the local AGN and the relic along with the discontinuities in X-ray observation hint us that we are looking at the site of re-acceleration.

• The Bulletin of The Korean Astronomical Society
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• v.42 no.2
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• pp.42.1-42.1
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• 2017

We present the results from an extensive spectroscopic survey of the central region of the nearby galaxy cluster Abell 2199 (A2199) at z=0.03. By combining 775 new redshifts from the MMT/Hectospec observations with the data in the literature, we construct a large sample of 1624 galaxies with measured redshifts at R<30', which redsults in high spectroscopic completeness at $r_{petro,0}$<20.5 (77%). We use these data to study the kinematics and clustering of galaxies, focusing on the comparison with those of the intracluster medium (ICM) from Suzaku X-ray observations. We identify 406 member galaxies of A2199 at R<30' using the caustic technique. The velocity dispersion profile of cluster members appears smoothly connected to the stellar velocity dispersion profile of the cD galaxy. The luminosity function is well fitted with a Schechter function at $M_r$<-15. The radial velocities of cluster galaxies generally agree well with those of the ICM, but there are some regions where the velocity difference between the two is about a few hundred kilometers per second. The cluster galaxies show a hint of global rotation at R<5' with $v_{rot}=300-600kms^{-1}$, but the ICM in the same region does not show such rotation. We apply a friends-of-friends algorithm to the cluster galaxy sample at R<60' and identify 32 group candidates, and examine the spatial correlation between the galaxy groups and X-ray emission. This extensive survey in the central region of A2199 provides an important basis for future studies of interplay among the galaxies, the ICM, and the dark matter in the cluster.

• The Korea Journal of Herbology
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• v.30 no.1
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• pp.11-18
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• 2015

Objectives : The objective of this study is to evaluate antioxidant activity and the main component content change of steaming-drying fermented Gastrodiae rhizoma extract. Methods : The antioxidant activities were determined for total polyphenol, flavonoid contents, SOD-like activity, electron donating activity, nitrite scavenging ability and major functional components(gastrodin and 4-hydroxybenzyl alcohol content) were also measured. Results : The polyphenol content of fermented Gastrodiae rhizoma by S. cerevisiae were higher than those of fermented Gastrodiae rhizoma by A. oryzae, and when the fermentation period is extended. SOD like activity of fermented Gastrodiae rhizoma showed to be increased by fermentation with S. cerevisiae than fermentation by A. oryzae. Electron donating activity of fermented Gastrodiae rhizoma were increased at almost parallel level as vitamin C, by fermentation. Notably, fermentation by A. oryzae was moderately better than fermentation by S. cerevisiae. Flavonoid content of Gastrodiae rhizoma showed to increasing by fermentation, particularly fermentation by S. cerevisiae was proven to be more effective than by A. oryzae. The more steaming-drying or increased period of fermentation would be resulted in more gastrodin contents but under the same conditions, 4-hydroxybenzyl alcohol content of fermentation by A. oryzae in case of steaming and drying 1 time and 3 time was higher than control. Conclusions : These results has strongly hint the possible applicability of fermentation might be effective to improve the diverse biological activities of Gastrodiae rhizoma and may further supports to develop a functional food materials.

• Journal of the Korean earth science society
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• v.26 no.7
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• pp.725-731
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• 2005

The distribution and kinematic information of the planetary nebula (PN) may provide a hint about the Galactic dynamics and evolutionary history. An analysis of the Galactic planetary nebular distribution and kinematics (distance, direction, velocity) is underwent, using the 502 PNs observational data given in the ‘THE STRASBOURG-ESO CATALOGUE OF GALACTIC PLANETARY NEBULAE.’ The representative average radial velocities, $(V_r)s$ is derived in six different directions of galactic latitudes, $l = 0^{\circ},\;90{\circ},\;180{\circ},\;270{\circ},$ plus apex and antapex $(56{\circ},\;236{\circ})$, respectively. The PNe near the apex approaches to the Sun with radial velocities, which values are $(V_r) = 69.0 km/s;$ whereas, those near the antapex recedes with $(V_r) = 64.1 km/s$, respectively. No particular trends are found along the z direction, although more PNs are found below the Galactic plane. This implies that the 3rd generation objects, PNs, move slowly on the galactic plane compared to the 4th generation stars like the Sun, indicative of possible interaction.

• The Bulletin of The Korean Astronomical Society
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• v.42 no.2
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• pp.80.1-80.1
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• 2017

We present preliminary results of KVN single dish telescope observations of 80 dense cores in the Orion molecular cloud complex which contains the Orion A, B, and ${\lambda}$ Orionis cloud. We investigate the behavior of the different molecular tracers and look for chemical variations of cores in the three clouds in order to systematically investigate the effects of stellar feedback. The most commonly detected molecular lines (with the detection rates higher than 50%) are N2H+, HCO+, H13CO+, C2H, HCN, and H2CO. The detection rates of dense gas tracers, N2H+, HCO+, H13CO+, and C2H show the lowest values in the ${\lambda}$ Orionis cloud. We find difference between molecular D/H ratios and N2H+/H13CO+ abundance ratios towards different clouds, and between protostellar cores and starless cores. Eight starless cores in the Orion A and B clouds exhibit high deuterium fractionations, larger than 0.10, while in the ${\lambda}$ Orionis cloud, no cores reveal the high ratio. These chemical properties could support that cores in the ${\lambda}$ Orionis cloud are affected by the photo-dissociation and external heating from the nearby H II region, which is a hint of negative stellar feedback on core formation. The striking difference between the [N2H+]/[H13CO+] ratios leads us to suggest that there are significant evolutionary differences between the Orion A/B and ${\lambda}$ Orionis clouds. In order to examine whether starless cores can be candidates of pre-stellar cores, we compared the core masses estimated from the 850 um emission to their Virial masses calculated from the N2H+ line data and find that most of them are not gravitationally bound in the three clouds.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2007.11a
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• pp.774-780
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• 2007

Occurrence amount of construction waste dominates weight that is the most as 44.6% if examine domestic waste occurrence present condition, scales of construction becomes jumbo gradually depending on social environment that change and occurrence amount of construction waste is steadily increasing real condition. Construction waste processing and recycling expense have held about 0.5% to 1% of whole construction cost, but if do not manage construction waste efficiently in each construction site, ratio that construction waste processing and recycling expense hold in whole construction cost is expected that will rise more. This does hint that environmental harm and economical damage are serious by construction waste. In this study, system is activated in each construction site at information interchange system and waste electron succession and waste government official makes radio frequency realization technology (RFID) purpose suggest plan that can be applied efficiently through example analysis that a RFID technology is already applied by efficiently attained plan.

• Journal of the Korean Geotechnical Society
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• v.33 no.9
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• pp.61-69
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• 2017

This study presents the experimental results of $CaCO_3$ formation in sand by the Enzyme Induced Carbonate Precipitation (EICP) method. Concentration of $CaCO_3$ with elapsed reaction time is calibrated by standardized procedure by measuring $CO_2$ pressure, and it increases with time towards asymptotic value. Jumunjin sand saturated with EICP solution shows that both shear wave velocity and electrical conductivity sharply increase as the reaction starts to approach to the constant values after 50 hours of reaction time. Urease concentration of 0.5 g/L exhibits 224% higher final shear wave velocity than that of 0.1 g/L. The nucleation models hint that carbonate tends to precipitate not only at grain contacts but also at grain surfaces. Regardless of urease concentration, electrical conductivity and shear wave velocity follow the unique path. The scanning electron microscopic images and X-ray computed tomographic images validate the spatial configuration of produced $CaCO_3$ in soils.