• 천문학회지
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• 제52권5호
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• pp.181-205
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• 2019

There is evidence that the luminosities of Type Ia supernova (SN Ia) depend on their environments. While the impact of this trend on estimating cosmological parameters is widely acknowledged, the origin of this correlation is still under debate. In order to explore this problem, we first construct the YONSEI (YOnsei Nearby Supernova Evolution Investigation) SN catalog. The catalog consists of 1231 spectroscopically confirmed SNe Ia over a wide redshift range (0.01 < z < 1.37) from various SN surveys and includes light-curve fit data from two independent light-curve fitters, SALT2 and MLCS2k2. For a sample of 674 host galaxies, we use the stellar mass and the star formation rate data in Kim et al. (2018). We find that SNe Ia in low-mass and star-forming host galaxies are $0.062{\pm}0.009mag$ and $0.057{\pm}0.010mag$ fainter than those in high-mass and passive hosts, after light-curve corrections with SALT2 and MLCS2k2, respectively. When only local environments of SNe Ia (e.g., locally star-forming and locally passive) are considered, this luminosity difference increases to $0.081{\pm}0.018mag$ for SALT2 and $0.072{\pm}0.018mag$ for MLCS2k2. Considering the significant difference in the mean stellar population age between the two environments, this result suggests that the luminosity evolution of SNe Ia with redshift is most likely the origin of the environmental dependence.

• 해양환경안전학회지
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• 제14권1호
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• pp.9-14
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• 2008

나노입자란 직경 100nm 이하의 크기를 가진 입자로 가전, 기능성 화장품, 반도체, 항균제 및 광촉매제 등에 널리 사용되어 있어 본 연구는 9종류의 나노입자가 참굴 수정란에 미치는 영향을 살펴보았다. 나인입자를 첨가하지 않은 대조구에서는 인공 수정한 참굴 수정란의 78%가 D형 유생으로 발생하였다. 은(Ag)이 2% 함유된 AGZ020, Nano silver 및 P-25의 나노입자와 주석산화물인 SnO의 나노입자는 24시간 경과 후 0.05ppm 농도에서 각 각 22%, 52%, 58% 및 76%가 D형 유생으로 발생하였으나, 20ppm 농도에서 8시간 이내 참굴 수정란을 모두 파괴하였다. In, Sb, Sn, Zn 및 Ag-$TiO_2$의 나노입자는 24시간 경과 후 0.05ppm 농도에서 모두 70%이상의 D형 유생으로 발생하여 상대적으로 낮은 농도에서 큰 영향을 받지 않는 것으로 나타났으나, 20ppm 농도에서 대조에 비해 D형 유생 발생율이 각 각 57%, 60%, 50%, 65% 및 64%로 저해되었다.

• 천문학회보
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• 제46권2호
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• pp.50.3-51
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• 2021

The progenitor of Type Ia supernovae is largely expected as a close binary system of a carbon/oxygen white dwarf (WD) primary and its secondary non-degenerate (single degenerate; SD) or degenerate companion (double degenerate; DD). Here we present a high-cadence monitoring observation of SN 2021hpr in a spiral galaxy, NGC 3147. SN 2021hpr shows typical characteristics as a normal type Ia supernova from its photometric (Δm₁₅(B)=1.01±0.03, dust free M_B,max=-19.45±0.02) and spectroscopic data. To investigate its progenitor system, we fit the early part of BVRI-band light curve simultaneously with a combined version of ejecta-companion and simple power-law model. As a result, we found a significant feature of an early excess possibly from a 7.63±0.52R_⊙-sized companion at the optimal viewing angle while the fit is not successful at the common viewing angle. No possible red sources brighter than F555W=-7.01 AB mag is detected at the SN location in Hubble Space Telescope (HST) pre-explosion images, excluding massive stars with initial mass of >16M_⊙ as companions. We suggest the progenitor system of SN 2021hpr can be a fairly large companion such as a main sequence, a low mass subgiant, and a helium giant star. In addition, a possibility of the ejecta-Disk Originated Matter (DOM) interaction for the DD scenario considering linearly-rising early flux still remains.

• 한국의류학회지
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• 제26권6호
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• pp.763-770
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• 2002

The objective of the study was to investigate skin temperature responses of Hanbok when it was worn. Two healthy females(average 21 years, 155cm and 60kg were exposed to a climatic chamber(Room Temp. $21{\pm}1^{\circ}C,\;52{\pm}2%R.H.$, 0.15m/s). During the experiment, rectal temperature, skin temperature of 9 areas, clothing microclimate, subjective sensation were measured. Chima and Jogory to be made of silk nobang(SN) or Ramie were worn for summer. Polyester(P) Chima and Jogori(R) could be wort for spring and autumn. For winter, silk Chima, Jogori(S) and Durumagi(D) were commonly worn. Rectal temperature was high in order of naked(N), R, SN, P, S, D. However Mean skin temperature was reversely high in order of D, S, SN, R, P, naked. In naked, skin temperature was high in order of head, trunk upper extremity and lower extremity. But on wearing of Hanbok, it was the highest at the chest except head regardless of kinds of clothing ensembles. Skin temperature of upper arm was secondly highest on wearing the silk ensemble and the Durumagi ensemble, but skin temperature of buttock was secondly highest on wearing the silk nobang ensemble and the ramie ensemble. Skin temperature on wearing the silk ensemble was generally higher than those on other clothing ensembles. Local and mean skin temperatures on wearing the silk ensemble and the Durumagj ensemble were generally higher than on other clothing ensembles. Heat resistance of the fabric might have affected on the local skin temperature.

• 천문학회보
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• 제43권2호
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• pp.51.5-52
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• 2018

The origin of dust in the early Universe has been the subject of considerable debate. Core-collapse supernovae (ccSNe), which occur several million years after their massive progenitors form, could be a major source of that dust, as in the local universe several ccSNe have been observed to be copious dust producers. Here we report nine near-infrared (0.8 - 2.5 micron spectra of the Type II-P SN 2017eaw in NGC 6946, spanning the time interval 22 - 205 days after discovery. The spectra show the onset of CO formation and continuum emission at wavelengths greater than 2.1 micron from newly-formed hot dust, in addition to numerous lines of hydrogen and metals, which reveal the change in ionization as the density of much of the ejecta decreases. The observed CO masses estimated from an LTE model are typically 0.0001 Msun during days 124 - 205, but could be an order of magnitude larger if non-LTE conditions are present in the emitting region. The timing of the appearance of CO is remarkably consistent with chemically controlled dust models of Sarangi & Cherchneff.

• 한국식품저장유통학회지
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• 제17권3호
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• pp.376-383
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• 2010

견과류 중 sunflower seed, cashew nut, walnut, pistachio, pumpkin seed, ginkgo, hazel nut, pecan을 원료로 하여 지방산 조성 분석 및 sn-2 position 분석, triacylglycerol species의 분석, tocopherol, phytosterol 함량을 분석하였다. 조지방 함량은 hazel nut에서 약 39.60 wt%로 가장 높았으며, walnut 35.25 wt%, pistachio 30.22 wt% 등의 순이었다. GC에 의한 sn-2 위치의 지방산 조성 분석 결과, oleic acid의 함량이 많은 견과류는 cashew nut, pistachio, hazel nut, pecan 이였으며, 특히 ginkgo의 경우 특이적으로 oleic acid의 이성체인 vaccenic acid가 10.72 wt% 나타냄을 확인할 수 있었다. 반면, linoleic acid 등이 높은 견과류는 sunflower seed, walnut, pumpkin seed 이었다. 견과류들의 TAG species의 PN값은 40∼52 사이에 존재하였다. Tocopherol의 함량은 ginkgo, sunflower seed, pumpkin seed 등에서 각각 48.57, 38.35, 31.43 mg/100 g 순으로 높은 함량을 나타내었다. 또한 총 phytosterol의 경우 88.60∼947.20 mg/100 g 사이에 함량을 나타내었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1991년도 하계학술대회 논문집
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• pp.194-197
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• 1991

In this study, $(Pb_{0.99}La_{0.01})[(Sb_{1/2}Sn_{1/2})_{0.10}Ti_{0.25}Zr_{0.65}]O_3$, added $MnO_2$ (0-0.30[mol%]) ceramics were fabricated by the mixed oxide method. The sintering temperature and time were $1250[^{\circ}C]$, 2[hr], respectively. In the $(Pb_{0.99}La_{0.01})[(Sb_{1/2}Sn_{1/2})_{0.10}Ti_{0.25}Zr_{0.65}]O_3$ added $MnO_2$ (0.24[mol%]) specimens, relative dielectric constant and dielectric loss were minimum values 3.52, 0.003, respectively, and Curie temperature were highest values $256[^{\circ}C]$. Pyroelectric coefficient and voltage responsivity of the $(Pb_{0.99}La_{0.01})[(Sb_{1/2}Sn_{1/2})_{0.10}Ti_{0.25}Zr_{0.65}]O_3$, and added $MnO_2$ (0.24[mol%]) specimen were good values, $6.73{\times}10^{-8}[C/cm^2K],\;125[v/W]$, respectively. Figure of merit of pyroelectric current, voltage and detectivity of the specimen, $(Pb_{0.99}La_{0.01})[(Sb_{1/2}Sn_{1/2})_{0.10}Ti_{0.25}Zr_{0.65}]O_3$ added $MnO_2$ (0.24[mol%]) were good values $2.714{\times}10^{-8}[Ccm/J],\;7.706{\times}10^{-11}[Ccm/J],\;2.640{\times}10^{-8}[Ccm/J]$, respectively. Voltage responsivity of the $(Pb_{0.99}La_{0.01})[(Sb_{1/2}Sn_{1/2})_{0.10}Ti_{0.25}Zr_{0.65}]O_3$ added $MnO_2$ (0.24[mol%]) specimens were decreased with increasing the chopper frequency.

• 치과방사선
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• 제2권1호
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• pp.23-27
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• 1972

A roentgenographic cephalometric study was made on the soft and hard tissue profile of Korean adults. The subject consisted of 52 males and 54 females from 17 to 22 years of age and with normal occlusion and acceptable profile. Twenty one landmarks were plotted and two oriented lines named SnH line and SnV line were drawn on the tracings of all cephalograms. The means and the standard deviations from the subjects were calculated in each measuring category and the means were compared with those of male and femal samples. The results were obtained as follow: 1. In depth and height, individual variations and sex differences of the lower facial profile were larger than the upper face. 2. The sex differences of upper facial profile were larger in height than depth. 3. The individual variations and sex differences of the top of nose were the smallest in all measuring points. 4. The thickness of the soft tissue of upper face and upper lip in male sample were larger than those of female, but the same matter were not found in mental region.

• Journal of Welding and Joining
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• 제16권5호
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• pp.100-107
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• 1998

This paper describes fluxless soldering of reflow soldering process using solder foil instead of solder pastes. There is an increasing demand for the reliable solder connection in the recent high density microelectronic components technologies. And also, it is problem fracture of an Ozone layer due to freon as which is used to removal of remained flux on the substrate. This paper discussed joining phenomena, boudability and joining processes of microelectronics devices, such as between outer lead of VLSI package and copper pad on a substrate without flux. The shear strength of joints is 8 to 13 N using Sn/Pb (63/37 wt.%) solder foil with optimum joining conditions, meanwhile, in case of using Sn/In (52/48 wt.%) solder foil, it is possible to bond with low heating temperature of 550 K, and accomplish to high bonding strength of 25N in condition heating temperature of 650K. Finally, this paper experimentally shows fluxless soldering using solder foil, and accomplishes key technology of microsoldering processes.

• Bulletin of the Korean Chemical Society
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• 제27권1호
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• pp.44-52
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• 2006

New organotin(IV) derivatives with general formulae R_2SnL_2 and R_3SnL, where R = methyl, n-butyl, n-octyl and phenyl and HL is either 3-[N-(4-nitrophenyl)amido]-propenoic acid or 3-[N-(4-nitrophenyl)amido] propanoic acid have been synthesized in 1 : 2 and 1 : 1 molar ratio by different methods. The FTIR spectra clearly demonstrated that the organotin(IV) moieties react with [O,O] atoms of the ligands. The bonding and coordination behavior in these complexes are discussed on the basis of multinuclear (^1H,\,^{13}C,\,^{119}Sn) NMR and mass spectrometric studies. Antibacterial, and antifungal screening tests were performed for these compounds and reported here. These values were compared to those of the precursors and it was found that diorganotin(IV) complexes exhibit less activity as compared to triorganotin(IV) complexes . LD_{50} data were obtained by Brine Shrimp assay method. Insecticidal activity was performed for selective compounds by contact toxicity method.