• Publications of The Korean Astronomical Society
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• v.30 no.2
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• pp.535-537
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• 2015

Interpreting ultraviolet-to-infrared (UV-to-IR) observations of galaxies in terms of constraints on physical parameters-such as stellar mass ($M_{\ast}$) and star formation rate (SFR)-requires spectral synthesis modelling. We investigate how increasing the level of sophistication of the standard simplifying assumptions of such models can improve estimates of galaxy physical parameters. To achieve this, we compile a sample of 1048 galaxies at redshifts 0.7 < z < 2.8 with accurate photometry at rest-frame UV to near-IR wavelengths from the 3D-HST Survey. We compare the spectral energy distributions of these galaxies with those from different model spectral libraries to derive estimates of the physical parameters. We find that spectral libraries including sophisticated descriptions of galaxy star formation histories (SFHs) and prescriptions for attenuation by dust and nebular emission provide a much better representation of the observations than 'classical' spectral libraries, in which galaxy SFHs are assumed to be exponentially declining functions of time, associated with a simple prescription for dust attenuation free of nebular emission. As a result, for the galaxies in our sample, $M_{\ast}$ derived using classical spectral libraries tends to be systematically overestimated and SFRs systematically underestimated relative to the values derived adopting a more realistic spectral library. We conclude that the sophisticated approach considered here is required to reliably interpret fundamental diagnostics of galaxy evolution.

• The Bulletin of The Korean Astronomical Society
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• v.36 no.1
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• pp.88.1-88.1
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• 2011

We present the FIMS/SPEAR FUV continuum map of The Taurus - Auriga - Perseus (TPA) complex, which is one of the largest local association of dark clouds located in (l,b)~([152,180],[-28,0]). We also present the result of FUV dust scattering simulation, which is based on Monte Carlo Radiative Transfer(MCRT) technique. Before the simulation we generate the model cloud using Hipparcos 77834 stars and the calculation of their E(B-V). From the density-integrated image and the cross section image of the modeled cloud we confirmed that the Taurus cloud is located in ~130pc. The cloud north of the California nebula is known for its two layered structure and we confirm that using the cross section image of the modeled cloud. In our modeled cloud, that two clouds are located at ~130pc and at ~300pc, respectively. Over the whole region the result image of simulation is well correlated with the diffuse FUV observed with FIMS/SPEAR. The dense core of the Taurus cloud, however, is not revealed completely in the map.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.10a
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• pp.290-291
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• 2021

Defects in the coating process of plastic automotive components are caused by various causes and phenomena. The correlation between defect occurrence rate and meteorological and environmental conditions such as temperature, humidity, and fine dust was analyzed. The defect rate data categorized by type and cause was collected for a year from a automotive parts coating company. This data and its correlation with environmental condition was acquired and experimented by machine learning techniques to predict the defect rate at a certain environmental condition. Correspondingly, the model predicted 98% from fine dust and 90% from curtaining (runs, sags) and hence proved its reliability.

• The Journal of Korean Medicine
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• v.44 no.3
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• pp.163-169
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• 2023

Objectives: This study aimed to review the experimental research trends in asthma caused by particulate matter to conduct further researches, especially in clinical trials. Methods: We searched for the meaningful literature using medicinal herb for asthma through the Pubmed databases. Results: Finally, six studies were finally selected. These studies showed recent trends, from 2018 to 2021 and conducted mostly in South Korea. The type of fine dust and the method of inducing asthma are different for each paper, but the effective mechanism is relatively common. It was commonly confirmed that the ratio and number of eosinophils, th2 cells and related cytokines are decreased in BALF and lung tissue by administration of medicinal herb. Conclusions: Although the method of inducing asthma using fine dust has not yet been standardized, it is thought that more meaningful evaluation results can be derived if a standardized animal model is established in the future. Nevertheless, based on the results that herbal medicine is effective for particular matter induced asthma, it is expected that it will be the basis for expanding into future clinical studies.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.5
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• pp.91-96
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• 2012

The surface of bushing is contaminated with rain, dust, salt and others. A bushing with contaminations in air is serious problem in insulation. Therefore, it is important to understand the inspection and diagnoses of the safety. The ultra-violet rays(UV) camera has attracted interest from the view point of easy judgement. In this paper, we will report on the corona discharge characteristics of surface flashover model with contaminations in air. Also, UV images of discharge and corona pulse count in air are analyzed using prototype UV camera of Korea and a UV sensor with an optic lens. These results are studied at both AC and DC voltage under a non-uniform field.

• Design & Manufacturing
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• v.15 no.2
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• pp.49-55
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• 2021

In this study, CALPUFF, a three-dimensional atmospheric diffusion model, was used to predict the degree of influence of pollutants generated during clean center operation on surrounding areas. To drive the CALPUFF model, CALMET, a weather field calculation model, was used. Due to the influence of the wind field, air pollutants from the Clean Center diffused in the southeast direction, increasing the distribution area. SOx satisfies atmospheric environmental standards with an annual average value of 0.02 ppm or less NOx satisfies atmospheric environmental standards with an annual average value of 0.03 ppm or less. Dust (PM-10) satisfies atmospheric environmental standards with an annual average value of 50㎍/m³ or less and 24 hours average value of 100㎍/m³ or less. CO satisfies atmospheric environmental standards with an 8 hours average value of 9 ppm or less and an 1 hour average value of 25 ppm or less.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.2
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• pp.55.1-55.1
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• 2019

We investigate broadband emission properties of the pulsar wind nebula (PWN) 3C 58 using a spectral energy distribution (SED) model. We attempt to match simultaneously the broadband SED and spatial variations and emission about 3C 58 in X-ray band. We further the model to explain a possible far-IR feature of which a hint is recently suggested in 3C 58: a small bump at ~10^11 GHz in the PLANCK and Herschel band. While external dust emission may easily explain the observed bump, it may be internal emission of PWNe implying an another additional population of particles. Although significance for the bump in 3C 58 is not higher than other PWNe, here we explore possible origins of the IR bump using the emission model and find that a population of electrons with GeV energies can explain the bump. If it is produced in the PWN, it may provide new insights into particle acceleration and flows in PWNe.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.1
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• pp.60.1-60.1
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• 2015

High energy photons and mechanical energy produced by the process of star formation result in copious FIR molecular and atomic lines, which are important coolants of the system. Photons thermally or mechanically induced could dissociate water in the dense envelope to change relative abundances among the species of O, OH, and H2O. Here we analyze OH emission lines toward embedded young stellar objects (YSOs) observed as part of the Herschel open time key program, 'Dust, Ice, and Gas In Time (DIGIT)' in order to study the physical conditions of associated gas and the energy budget loaded on the OH line emission. According to our analysis of the Herschel/PACS spectra, OH emission peaks at the central spaxel in most of sources, but several sources show spatially extended emission structures. In the extended emission sources, the distribution of OH emission is correlated with that of [OI] emission and extended along the outflow directions. Considering the diversity of source properties, ratios between detected OH lines are relatively constant among sources. In addition, each OH line has strong correlation with bolometric luminosity. In order to determine the physical conditions of YSOs, we adopt several methods for the analysis of the OH lines: rotational diagram, non-LTE LVG analysis, and a 2-D PDR code. From the simple LVG analysis, we find that the thermal solution with the dense ( > $10^7cm^{-3}$) and warm ( ~ 100 K) OH gas reproduces the ratios of detected OH lines. However, our self-consistent PDR 2-D model, which can deal with the IR-pumping effect from the central protostar as well as the warm dust in situ, cannot fit the observational results, suggesting that an irradiated shock model is necessary for a better interpretation.

• Journal of the Korea Institute of Building Construction
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• v.9 no.5
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• pp.119-125
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• 2009

In this paper, the engineering properties and estimation of drying shrinkage of concrete incorporating fly ash (FA), blast furnace slag (BS) and cement kiln dust (CKD) were discussed. FA, BS and CKD contents ranged from 0% to 20%. Water to binder ratio (W/B) also ranged from 40 to 50 %, with a 5% interval. For estimating drying shrinkage, an exponential model proposed by the author was applied, According to results, the use of FA, BS and CKD resulted in a decrease of flowability and air contents. As expected, the use of admixtures also decreases the early age strength of concrete, while at later age, due to a pozzolanic reaction of FA and BS, the compressive strength was recovered to a value comparable with that of plain concrete. For drying shrinkage, the use of admixtures led to an increase in the drying shrinkage of concrete. The exponential model suggested by the author showed good agreement between the calculated and experimental values both at early age and at later age.

• Korea-Australia Rheology Journal
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• v.20 no.2
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• pp.59-63
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• 2008

A theoretical model was developed to describe the flow behavior of a filled polymer in the packing stage of reaction injection molding and predict the residual stress distribution of thin injection-molded parts. The model predictions were compared with experiments performed for phenol-formaldehyde resin filled with wood dust and cured by urotropine. The packing stage of reaction injection molding process presents a typical example of complex non-isothermal flow combined with chemical reaction. It is shown that the time evolution of pressure distribution along the mold cavity that determines the residual stress in the final product can be described by a single 1D partial differential equation (PDE) if the rheological behavior of reacting liquid is simplistically described by the power-law approach with some approximations made for describing cure reaction and non-isothermality. In the formulation, the dimensionless time variable is defined in such a way that it includes all necessary information on the cure reaction history. Employing the routine separation of variables made possible to obtain the analytical solution for the nonlinear PDE under specific initial condition. It is shown that direct numerical solution of the PDE exactly coincides with the analytical solution. With the use of the power-law approximation that describes highly shear thinning behavior, the theoretical calculations significantly deviate from the experimental data. Bearing in mind that in the packing stage the flow is extremely slow, we employed in our theory the Newtonian law for flow of reacting liquid and described well enough the experimental data on evolution of pressure.