• The Bulletin of The Korean Astronomical Society
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• v.40 no.1
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• pp.80.1-80.1
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• 2015

We present a study of outflows on 24 embedded young stellar objects selected from the source list of the Dust, Ice, and Gas in Time (DIGIT) Herschel key program. To study the relation between the CO outflows observed in low-J transitions and the properties of protostars more consistently with a homogeneous data set, we mapped the CO outflows of the selected targets in the J = 1-0 and J = 2-1 lines with two Korean telescopes (SRAO and TRAO). We compare CO outflow force ($F_{CO}$) with the bolometric luminosity, ($L_{bol}$) bolometric temperature, and the FIR molecular line luminosities of CO, $H_2O$, OH, and [O I] detected by the Herschel-PACS observations. We find that $F_{CO}$ of J = 1-0 is greater than that of 2-1 by a factor of ~ 2. The well known correlation between $F_{CO\;2-1}$ and $L_{bol}$ is not very evident in our sample as a whole, but they show a rather strong correlation when IRAM 04191+1522 is excluded. IRAM 04191+1522 has relatively high $F_{CO\;2-1}$ in spite of its low $L_{bol}$. This object is a well-known VeLLO, which is believed in the quiescent phase of the episodic mass accretion in the embedded stage. $L_{bol}$ traces a current accretion, but $F_{CO\;2-1}$ traces accretion happened long ago. Therefore, the low-$L_{bol}$ with the high-$F_{CO\;2-1}$ can be explained by the episodic accretion. $F_{CO\;2-1}$ shows little correlation with individual FIR line luminosities of CO, $H_2O$, OH, while [O I] and total FIR line luminosity seem to have correlations with $F_{CO\;2-1}$. This result is interpreted as the accretion energy deposits on species differently depending on shock properties, but the total FIR line luminosity sums the total accretion energy dispersed to different species.

• Korean Journal of Optics and Photonics
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• v.27 no.5
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• pp.165-173
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• 2016

In this paper, we propose a three-dimensional (3D) scanning system based on two line lasers. This system uses two line lasers with different wavelengths as light sources. 532-nm and 630-nm line lasers can compensate for missing scan data generated by geometrical occlusion. It also can classify two laser planes by using the red and green channels. For automatic registration of scanning data, we control a stepping motor and divide the motor's rotational degree of freedom into micro-steps. To this end, we design a control printed circuit board for the laser and stepping motor, and use an image processing board. To compute a 3D point cloud, we obtain 200 and 400 images with laser lines and segment lines on the images at different degrees of rotation. The segmented lines are thinned for one-to-one matching of an image pixel with a 3D point.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.161-161
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• 2017

Seed endophytes are very remarkable groups of bacteria for their unique abilities of being vertically transmitted and conserved. As plants attain hybrid vigor and heterosis in the process of crossbreeding, this might also lead to the changes in the community structure and diversity of plant endophytes in the hybrid plants ultimately affecting the endophytes of the seeds. It would be interesting to characterize how seed endophyte composition change over time. The objective of this study is to gain insights into the influence of natural crossbreeding and parental lineage in the seed bacterial endophytic communities of two pure inbred lines exploring contributions of the two most important sources of plant endophytes - colonization from external sources and vertical transmission via seeds. Total genomic DNA was isolated from rice seeds and bacterial DNA was selectively amplified by PCR. The diversity of endophytic bacteria was studied through Terminal-Restriction Fragment Length Polymorphism (T-RFLP) analysis. Diversity between the original parents and the pure inbred line may show significant differences in terms of richness, evenness and diversity indices. Heat maps reveal astonishing contributions of both or either parents (IR29 ${\times}$ Pokkali and AT401 ${\times}$ IR31868) in the shaping of the bacterial seed endophytes of the hybrid, FL478 and IC32, respectively. Most of the T-RFs of the subsequent pure inbred line could be traced to any or both of the parents. Comparison of common and genotype-specific T-RFs of parents and their offspring reveals that majority of the T-RFs are shared suggesting higher transmission of bacterial communities common to both parents. The parents influence the bacterial community of their offspring. Unique T-RFs of the offspring also suggest external sources of colonization particularly as the seeds are cultivated in different ecogeographical locations. This study showed that host parental lines contributed greatly in the shaping of bacterial seed endophytes of their offspring. It also revealed transmission and potential conservation of core seed bacterial endophytes that generally become the dominant microbiota in the succeeding generations of plant hosts.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.5
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• pp.491-498
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• 2005

J sewage treatment plant (WWTP) in Busan has used methanol as an external carbon source for the biological denitrification process. Methanol is widely used. but rather expensive and very dangerous in handling. Therefore, it has been required that the economic alternative carbon source must be developed. By-product from a fine chemical industry can be Purified by removing high molecular weight substances using the ultrafilter membrane separation process and RBDCOD fraction becomes $98{\sim}99%$ of COD substances in the purified by-product. The purified by-product containing three types of alcohols, methanol, prophylenglycol and methoxypropanol; showed similar chemical characteristics to the methanol, a main external carbon source, in biodegradation pathway. Shown above, the compatibility between main and alternative carbon sources has been achieved. Also very short or no adaptation period is necessary in the case of exchanging these carbon sources. The compatibility between external carbon sources is an essential element for stabilizing WWTP operations. During the full-scale application test of the by-product, the alternative carbon source line got on par with the treatment efficiency of the methanol line. With the test result, J-WWTP changed methanol to a fine chemical by-product, in two out of three J-WWTP lines. Moreover, it is expected that 55.4% of the external carbon source cost reduction can be achieved in the alternative carbon source applied lines.

• Spatial Information Research
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• v.6 no.1
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• pp.65-76
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• 1998

Air contaminant density must be inferred exactly to manage air pollution. Each land use of air pollution source is duplicated in the existing air contaminant distribution because the resolution of the land use map is low. The purpose of this study is to understand how the land use map is used to determine effectively in the distribution calculation of the emission volume and the inference of air contaminant density, as it is made in a high resolution. The major findings are as follows : In this study, as to making a high resolution($28.5m{\times}28.5m$) map of land use with GIS, each air pollution source is not duplicated spatially and land use can be reflected effectively. In Seoul, each air contaminant density was inferred (using a TCM-2 model) with the existing distribution map of emission volume, whose resolution is $1km{\times}1km$, and the new distribution map of emission volume, whose resolution is $28.5km{\times}28.5km$. According to the result, the inference value of the new distribution map was more similar to the actual value of an automatic survey network.

• Journal of Preventive Medicine and Public Health
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• v.40 no.4
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• pp.291-296
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• 2007

Objectives : To explore the information sources and knowledge on infant vaccinations of pro-vaccination community members and anti-vaccination community members on the internet. Methods : An online survey of 245 parents from three pro-vaccination communities and 92 parents from one anti-vaccination community was conducted from June 7 to June 23, 2006. Results : Parents from pro-vaccination communities usually gained the information regarding vaccination efficacy and risk mainly from healthcare providers (49.8%) and mass media (47.7%). Pro-vaccination community members considered healthcare providers as the most credible sources of information on vaccination, whereas the anti-vaccination community members usually gained their information regarding vaccine efficiency and risk from Internet child-care cafes and online vaccination communities. Parents of the anti-vaccination community considered the internet as the most credible information source (77.6% for efficacy, 94.8% for risk). In addition, the major reason why anti-vaccination community members didn't vaccinate and, will not vaccinate, was concern about possible side effects of the vaccine. The knowledge level on infant vaccination, education and economic status was higher in the anti-vaccination community. Conclusions : On-line communities concerned with vaccination are getting popular. The influence of anti-vaccination parents on the Internet is expected to be high. The government and healthcare providers need to increase their efforts to improve the credibility of information about vaccination. Our findings suggest that online communication regarding vaccinations needs to be considered as a means to increase vaccination rates.

• Journal of the Korea Fashion and Costume Design Association
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• v.20 no.4
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• pp.57-71
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• 2018

Since consumers have become more comfortable with providing and receiving information online, 'online word of mouth' has been gaining consideration as one of the major information sources. Also, the shopping orientation of consumers has been proven to be an important determinant of consumer behavior. Therefore, the study investigated the differences in online WOM behavior based on shopping orientation. Hedonic, loyal, and syntonic styles were the types of shopping orientation considered, and the study focused on information retrieval tendencies, the motivation of online WOM search, searching online WOM sources, and the contents for the online WOM behavior. The research conducted an off-line survey targeting females in their twenties. The total number of data sets used in the empirical study was 125, and these were analyzed by SPSS 20.0: factors analysis, Cronbach's ${\alpha}$, k-means cluster, ANOVA, Duncan's multiple range test, Kruskal-Wallis, Mann-Whitney, and Bonferroni correction. The participants were divided into 3 kinds of shopping orientation groups named 'trend-pursuit', 'passive', and 'loyal'. As a result, there were significant differences in online WOM behavior discovered between the groups. Firstly, the 'trend-pursuit' group had the highest number of ongoing searches while the 'loyal' group had the highest number of pre-purchase search. Secondly, the 'trend-pursuit' and 'loyal' groups both had the motivations of online WOM search, hedonic and utility, whereas the 'passive' group had the lowest motivations for both motivations. Thirdly, the 'loyal' group frequently referred to reviews on shopping malls as online WOM sources. The research provided a better understanding of the online WOM behavior of present consumers and suggests that fashion related corporations map out marketing strategies with the understanding of these behaviors.

• International Journal of Computer Science & Network Security
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• v.22 no.10
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• pp.97-106
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• 2022

Objective. Nanotechnology is spreading among all areas of life, from everyday devices to medicine. The concept of nanotechnology argues that not only can new physical and chemical properties of materials be discovered, but also the new potential of nanostructures when reduced to the nanoscale. The growing interest in the application of nanomaterials in dentistry contributes to the proliferation of the range of nanomaterials used by specialists. The purpose of this review of information sources was to analyze the prospects for the use of nanomaterials in dentistry. Methods. We used the bibliographic semantic method of research, for which we analyzed electronic databases of primary literature sources Scopus, Web of Science, Research Gate, PubMed, MDPI, and MedLine. English-language scientific articles published after 2017 were taken into consideration. Results. According to the results of a search study among modern information primary sources, nanotechnology improves the preventive properties of oral care products, improves the structural-mechanical and aesthetic properties of composite mixtures for dentistry, overcomes the problems of the clinical application of dental implants. Despite the prospects of nanotechnology applications in medicine in general and dentistry in particular, the existing economic and technological problems require a thorough solution for further implementation of nanostructures. Scientific novelty. For the first time, the analysis of modern trends in the application of nanotechnology in dentistry is carried out and the peculiarities of materials are highlighted, the problems and prospects of nanostructures implementation in modern dental implantology are given, physical, chemical, mechanical, and antibacterial properties of nanomaterials are evaluated. The effect of nanomaterials on the microbial adhesion of the tooth or implant surface is described. Practical significance. The presented publication can become a scientific basis for the solution of urgent problems hindering the introduction of nanotechnology into dental practice. Conclusions. Thus, the use of nanostructures opens up great opportunities for the treatment of a wide range of diseases, not only of dental nature but also in medicine in general.

• Journal of Electrical Engineering and Technology
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• v.13 no.6
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• pp.2545-2552
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• 2018

$SF_6$ has been widely used in high voltage power equipment, such as gas insulated switchgear (GIS) and gas insulated transmission line (GIL), because of its excellent insulation and arc extinguishing performance. However, $SF_6$ faces two environmental problems: greenhouse effect and high liquefaction temperature. Therefore, to find the $SF_6$ substitute gases has become a research hotspot in recent years. In this paper, the liquefaction characteristics of $SF_6$ substitute gases were studied. Peng-Robinson equation of state with the van der Waals mixing rule (PR-vdW model) was used to calculate the dew point temperature of the binary gas mixtures, with $SF_6$, $C_3F_8$, $c-C_4F_8$, $CF_3I$ or $C_4F_7N$ as the insulating gas and $N_2$ or $CO_2$ as the buffer gas. The sequence of the dew point temperatures of the binary gas mixtures under the same pressure and composition ratio was obtained. $SF_6/N_2$ < $SF_6/CO_2$ < $C_3F_8/N_2$ < $C_3F_8/CO_2$ < $CF_3I/N_2$ < $CF_3I/CO_2$ < $c-C_4F_8/N_2$ < $C_4F_7N/N_2$ < $c-C_4F_8/CO_2$ < $C_4F_7N/CO_2$. $SF_6/N_2$ gas mixture showed the best temperature adaptability and $C_4F_7N/CO_2$ gas mixture showed the worst temperature adaptability. Furthermore, the dew point temperatures of the $SF_6$ substitute gases at different pressures and the upper limits of the insulating gas mole fraction at $-30^{\circ}C$, $-20^{\circ}C$ and $-10^{\circ}C$ were obtained. The results would supply sufficient data support for GIS/GIL operators and researchers.

• Journal of Electrical Engineering and Technology
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• v.13 no.6
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• pp.2402-2411
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• 2018

Fluoronitriles-$CO_2$ gas mixtures are promising alternatives to $SF_6$ in environmentally-friendly gas-insulated transmission lines (GILs). Insulating gas heat transfer characteristics are of major significance for the current-carrying capacity design and operational state monitoring of GILs. In this paper, a three-dimensional calculation model was established for a GIL using the thermal-fluid coupled finite element method. The calculated results showed close agreement with experimentally measured data. The temperature distribution of a GIL filled with the Fluoronitriles-$CO_2$ mixture was obtained and compared with those of GILs filled with $CO_2$ and $SF_6$. Furthermore, the effects of the mixture ratio of the component gases and the gas pressure on the temperature rise and current-carrying capacity of the GIL were analyzed. Results indicated that the heat transfer performance of the Fluoronitriles-$CO_2$ gas mixture was better than that of $CO_2$ but worse than that of $SF_6$. When compared with $SF_6$, use of the Fluoronitriles-$CO_2$ gas mixture caused a reduction in the GIL's current-carrying capacity. In addition, increasing the Fluoronitriles gas component ratio or increasing the pressure of the insulating gas mixture could improve the heat dissipation and current-carrying capacity of the GIL. These research results can be used to design environmentally-friendly GILs containing Fluoronitriles-$CO_2$ gas mixtures.