• Journal of the Korean Crystal Growth and Crystal Technology
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• v.31 no.1
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• pp.8-15
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• 2021

TiO2 has been used in various fields such as solar cells, dental implants, and photocatalysis, because it has high physical and chemical stability and is harmless to the body. TiO2 nanofibers which have a large specific surface area also show a good reactivity in bio-friendly products and excellent photocatalysis in air and water purification. To fabricate TiO2 nanofibers, an electrospinning method was used. To observe the diameter of TiO2 nanofibers with fabrication variables, the fabrication variables was divided into precursor composition variables and process variables and microstructure was analyzed. The concentrations of PVP (Polyvinylpyrrolidone) and TTIP (Titanium(IV) isopropoxide) were selected as precursor composition variables, and inflow velocity and voltage were also selected as process variables. Microstructure and crystal structure of TiO2 nanofibers were analyzed using FE-SEM (Field emission scanning electron microscope) and XRD (X-ray diffraction), respectively. As-spun TiO2 nanofibers with an average diameter of about 0.27 ㎛ to 1.31 ㎛ were transformed to anatase TiO2 nanofibers with an average diameter of about 0.22 ㎛ to 0.78 ㎛ after heat treatment of 3 hours at 450℃. Anatase TiO2 nanofibers with an average diameter of 0.22 ㎛ can be expected to improve the photocatalytic properties by increasing the specific surface area. To change the average diameter of TiO2 nanofibers, the control of precursor composition variables such as concentrations of PVP and TTIP is more efficient than the control of electrospinning process variables such as inflow velocity and voltage.

• Sleep Medicine and Psychophysiology
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• v.27 no.2
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• pp.67-76
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• 2020

Objectives: Brain maturation involves brain lateralization and asymmetry to achieve efficient information processing and cognitive controls. This study elucidates normal brain maturation change during the gap between ages 6-9 and age 14-17 using resting EEG. Methods: An EEG dataset was acquired from open source MIPDB (Multimodal Resource for Studying Information Processing in the Developing Brain). Ages 6-9 (n = 24) and ages 14-17 (n = 26) were selected for analysis, and subjects with psychiatric illness or EEG with severe noise were excluded. Finally, ages 6-9 (n = 14) and ages 14-17 (n = 11) were subjected to EEG analysis using EEGlab. A 120-sec length of resting EEG when eyes were closed was secured for analysis. Brain topography was compartmentalized into nine regions, best fitted with brain anatomical structure. Results: Absolute power of the delta band and theta band in ages 6-9 was greater than that of ages 14-17 in the whole brain, and, also is relative power of delta band in frontal compartment, which is same line with previous studies. The relative power of the beta band of ages 14-17 was greater than that of ages 6-9 in the whole brain. In asymmetry evaluation, relative power of the theta band in ages 14-17 showed greater power in the left than right frontal compartment; the opposite finding was noted in the parietal compartment. For the alpha band, a strong relative power distribution in the left parietal compartment was observed in ages 14-17. Absolute and relative power of the alpha band is distributed with hemispheric left lateralization in ages 14-17. Conclusion: During the gap period between ages 6-9 and ages 14-17, brain work becomes more complicated and sophisticated, and alpha band and beta band plays important roles in brain maturation in typically developing children.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.26 no.3
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• pp.220-237
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• 2021

Since the functional importance of marine phytoplankton was firstly advocated from early 1880s massive data on the species composition and abundance were produced by classical microscopic observation and the advanced auto-imaging technologies. Recently, pigment composition resulted from direct chemical analysis of phytoplankton samples or indirect remote sensing could be used for the group-specific quantification, which leads us to more diversified data production methods and for more improved spatiotemporal accessibilities to the target data-gathering points. In quite a few cases of many long-term marine ecosystem monitoring programs the phytoplankton species composition and abundance was included as a basic monitoring item. The phytoplankton data could be utilized as a crucial evidence for the long-term change in phytoplankton community structure and ecological functioning at the monitoring stations. Usability of the phytoplankton data sometimes is restricted by the differences in data producers throughout the whole monitoring period. Methods for sample treatments, analyses, and species identification of the phytoplankton species could be inconsistent among the different data producers and the monitoring years. In-depth study to determine the precise quantitative values of the phytoplankton species composition and abundance might be begun by Victor Hensen in late 1880s. International discussion on the quality assurance of the marine phytoplankton data began in 1969 by the SCOR Working Group 33 of ICSU. Final report of the Working group in 1974 (UNESCO Technical Papers in Marine Science 18) was later revised and published as the UNESCO Monographs on oceanographic methodology 6. The BEQUALM project, the former body of IPI (International Phytoplankton Intercomparison) for marine phytoplankton data QA/QC under ISO standard, was initiated in late 1990. The IPI is promoting international collaboration for all the participating countries to apply the QA/QC standard established from the 20 years long experience and practices. In Korea, however, such a QA/QC standard for marine phytoplankton species composition and abundance data is not well established by law, whereas that for marine chemical data from measurements and analysis has been already set up and managed. The first priority might be to establish a QA/QC standard system for species composition and abundance data of marine phytoplankton, then to be extended to other functional groups at the higher consumer level of marine food webs.

• Clean Technology
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• v.28 no.1
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• pp.38-45
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• 2022

CuCl₂-loaded V₂O₅-WO₃/TiO₂ catalyst showed excellent activity in the catalytic oxidation of elemental mercury to oxidized mercury even under SCR condition in the presence of NH₃, which is well known to significantly inhibit the oxidation activity of elemental mercury by HCl. Moreover, it was confirmed that, when SO₂ was present in the reaction gas together with HCl, excellent elemental mercury oxidation activity was maintained even though CuCl₂ supported on the catalyst surface was converted to CuSO₄. This is thought to be because not only HCl but also the SO₄ component generated on the catalyst surface promotes the oxidation of elemental mercury. However, in the presence of SO₂, the total mercury balance before and after the catalytic reaction was not matched, especially as the concentration of SO₂ increased. In order to understand the cause of this, further studies are needed to investigate the effect of SO₂ in the SnCl₂ aqueous solution employed for mercury species analysis and the effect of sulfate ions generated on elemental mercury oxidation. It was confirmed that SO₂ also promotes NO_x removal activity, which is thought to be because the increase in acid sites by SO₄ generated on the catalyst surface by SO₂ facilitates NH₃ adsorption. The composition change and structure of the components present on the catalyst surface under various reaction conditions were measured by XRD and XRF. These measurement results were presented as a rational explanation for the results that SO₂ enhances the oxidation activity of elemental mercury and the NO_x removal activity in this catalyst system.

• Journal of Popular Narrative
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• v.27 no.2
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• pp.107-142
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• 2021

Emergence of new media platform had changed relationship between the broadcaster and the viewer, which used to form 'performer-audience' structure. This research has focused on the transition of 'streamer-viewer' role in single-media broadcasting, such as Youtube or Twitch, and identify how they progress group storytelling as a team. Walter Benjam and Leslie Marmon Silko's notion of 'story and storyteller' and Erving Goffman's 'social role theory' was used to define participants' role in new media broadcasting. channel, on Youtube, was selected and analyzed as example case. The domain of 'front stage' was broadened in recorded contents comparing to live streaming. The audience of live streaming is included to the front stage during the expansion. The role of streamer, game participant, and live stream contents viewer is also adjusted during the change, which leads to group-creation of the contents. Streamer plays a role of main-storyteller and suggest identity of the community. Game participants work as sub-storyteller, filling in the blank space in game storytelling and making it sophisticated. They also perform based on community's identity, which streamer has built in advance. Lastly, live steam viewers are intermittent sub-storyteller, which seldom add up the narrative. Though, their main role is to preserve identity of game broadcasting community by reacting according to community's identity. As a result, the game broadcasting narrative is developed by combining and adding up pieces of story made in different level and role of participants. The research redefine the role of viewer and storytelling method in new media, especially in single-person broadcasting. Considering the rapid shift in recent media and contents, a new approach to the streamer-veiwer role and group storytelling of this research can be one of the new method to analyze contents produced in new media, such as Youtube.

• Economic and Environmental Geology
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• v.54 no.6
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• pp.709-716
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• 2021

In this study, an adsorbent prepared by natural drying of iron hydroxide-based sludge collected from settling basin at a mine drainage treatment facility located in Gangneung, Gangwon-do was used to remove fluoride in an artificial fluoride solution and mine drainage, and the adsorption characteristics of the adsorbent were investigated. As a result of analyzing the chemical composition, mineralogical properties, and specific surface area of the adsorbent used in the experiment, iron oxide (Fe₂O₃) occupies 79.2 wt.% as the main constituent, and a peak related to calcite (CaCO₃) in the crystal structure analysis was analyzed. It was also identified that an irregular surface and a specific surface area of 216.78 m²·g^-1. In the indoor batch-type experiment, the effect of changes in reaction time, pH, initial fluoride concentration and temperature on the change in adsorption amount was analyzed. The adsorption of fluoride showed an adsorption amount of 3.85 mg·g^-1 16 hours after the start of the reaction, and the increase rate of the adsorption amount gradually decreased. Also, as the pH increased, the amount of fluoride adsorption decreased, and in particular, the amount of fluoride adsorption decreased rapidly around pH 5.5, the point of zero charge at which the surface charge of the adsorbent changes. Meanwhile, the results of the isotherm adsorption experiment were applied to the Langmuir and Freundlich isotherm adsorption models to infer the fluoride adsorption mechanism of the used adsorbent. To understand the thermodynamic properties of the adsorbent using the Van't Hoff equation, thermodynamic constants 𝚫H° and 𝚫G° were calculated using the adsorption amount information obtained by increasing the temperature from 25℃ to 65℃ to determine the adsorption characteristics of the adsorbent. Finally, the adsorbent was applied to the mine drainage having a fluoride concentration of about 12.8 mg·L^-1, and the fluoride removal rate was about 50%.

• Korean Journal of Heritage: History & Science
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• v.55 no.2
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• pp.24-48
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• 2022

Bronze mirrors found in pagodas were regarded as simple offerings and thus have received little attention in studies. Furthermore, the few studies on bronze mirrors enshrined in pagodas have focused on the line-engraved mirrors found in the pagodas of the Kingdom of Wuyue; therefore, it is difficult to understand the general characteristics of the bronze mirrors enshrined in the pagodas. This study assumes that the bronze mirrors found in many pagodas in the Kingdom of Wuyue and the Song dynasty were enshrined for a specific purpose. To explore this assumption and accurately understand the artifacts, this study focuses on the location and method of enshrinement. The number of bronze mirrors enshrined in pagodas increased during the Kingdom of Wuyue, with the mirrors expressing statues and inscriptions related to Buddhism rather than being simple offerings. This shows that the purpose of the bronze mirror changed. The influence of the Kingdom of Wuyue continued during the Song dynasty; however, the pattern of bronze mirror enshrinement changed due to the culture and social atmosphere of the time. The most common types of enshrined bronze mirrors were plain, and bronze mirrors from the Dang dynasty were also used consistently. Plain bronze mirrors were used more frequently in this period despite the lingering influence of the Kingdom of Wuyue because it was less laborious to engrave images and inscriptions such as the inscription of Buddha. Additionally, bronze mirrors were valued during this period because of the attention toward the imitation of the archaic bronze(仿古銅器) of the Song dynasty and the influence of the emperor. Moreover, it is believed that bronze mirrors were enshrined in pagodas as offerings as they were deemed valuable at the time. There was a change in the method of enshrining bronze mirrors in pagodas during the Kingdom of Wuyue and the Song dynasty. During this time, bronze mirrors that were positioned on the floor or in iron boxes were intentionally attached to walls or hung from the ceiling. This method was largely divided into two types: attaching to walls or the ceiling(嵌入鏡) and hanging from the ceiling(懸鏡). A typical example of hanging a bronze mirror from the ceiling can be seen in the Jingzhisa Temple Pagoda, and Teng County's Fushengsa Temple Pagoda contains an example of attaching a bronze mirror to the ceiling. The methods of hanging or attaching bronze mirrors to the ceiling were closely related to the methods employed in Chinese tombs. Song dynasty burial chambers had a high and wide structure, so to defend against evil spirits(辟邪用), bronze mirrors were used to protect the burial rooms. Bronze mirrors were, therefore, placed high to illuminate the burial room. This was achieved in the ways mentioned above. As underground chambers became wider and higher, mirrors also protected the important areas of the chambers and illuminated the interiors. Thus, it is believed that the methods of enshrining bronze mirrors in the pagodas during the Kingdom of Wuyue and the Song dynasty arose from the method of enshrining bronze mirrors in tombs at the time. Thereafter, pagodas, such as the Miaojuesa Temple Pagoda, in which the placement of a bronze mirror was actively considered from the design stage were constructed.

• Korean Journal of Social Welfare Studies
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• v.42 no.3
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• pp.291-327
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• 2011

The purpose of this study is to classify the type of retirement process among the mature-aged in Korea. The study used the panel data from Korean Labor Panel (year2~6) for the classification of retirement process through Optimal Matching and Cluster Analysis. Classification is made in 5 categories as 'peripheral-economically active', 'private-transfer dependent', 're-entering limited', 'securely exiting', 'exit-and-reentering'. First, "peripheral-economically active" is a group which frequently experienced job status change and work insecurity. Second, "private-transfer dependent" is a group in which private transfer is likely to be supplements income in the incidence of unemployment. Third, "re-entering limited" is a group in which the proportion of no financial support combined with the absence of any economic activity is the largest. Fourth, the type "Securely exit" is th group whose members switches over to non-economically active status with pension receipt. The last type is "exit-and-reenter" that the member are highly possible to reenter in the labor market and stay in long time regardless of with or without pension plan. To examine the inequality among the types of retirement process, the duration of each status is analyzed. First, in the situation of being non-economically active, the duration of status is maintain public pension receiving and duration stabile in "securely exit" group. For "private-transfer dependent" type, members are mostly dependent on private financial support and that duration of it is longest. Through the analysis of retirement process without under other financial supports, it is "securely-exiting" type for which the duration of full-time employment is longest. It appears that the duration of part-time employment is longest in "peripheral-economically active" type. And for the case of non-waged employment it is "exit-and-reenter" type. Finally, the redistribution policy based on life course perspective is necessary to prevent that the opportunity in the structure before retirement stage and the unfavorable position in labor market make worse disadvantage in retirement process and after that.

• (The) Research of the performance art and culture
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• no.19
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• pp.5-33
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• 2009

Jain-Danoje's course since modern is not different with almost all of folk performances, which were restored and reconstructed with a background of the designation of an intangible cultural heritage and National folk arts contest sine the 1960s. Generally, these folk performances were decontextualized in course of extinction and reappearance, and recontextualized in course of new directions on tradition. Also, the performances were interpreted differently and transformed by the main constituents of reappearance. Jain-Danoje nowadays has a regular form just at that time that has been designated as a cultural heritage at 1970s. But, today's Jain-Danoje is clearly different with the last appearance in 1936 and some Literature and jainhyun-eupji. I think such differences would stems from the process of reproduction. From this perspective, I had investigate Old literature and the early days report, and the current text. Especially, I will show the considerable change which has been occurred in the Yeowonmu and Hojanggut, the central role to configure that identity, by comparing past and today. As a result of consideration, today's form of the Yeowonmu and Hojanggut are created texts that mind the designation of an intangible cultural heritage and National folk arts contest. These texts has been reproduced without understanding about structure and current of folk festival and state of performance which has been transmitted on premodern society. some intellectuals search for an archaic form of Jain-Danoje based on jainhyun-eupji that created in 1895, except the other jainhyun-eupji. Moreover, because of the understanding with a bias, they can't grasp the meaning about the religious service for Hanjanggun, and they can't see the facts of Yeowonmoo. In addition, they were aware of 'o-sin' that led by Hojang as a fancy dress parade in a carnival, and that is recognized as a component of Jain-Danoje, so there was other text which is different from our own festival.

• Korean Journal of Environmental Biology
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• v.40 no.1
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• pp.112-123
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• 2022

To assess the influence of environmental factors on the phytoplankton community structure and total phytoplankton biomass during four seasons in 2014, we investigated the abiotic and biotic factors at 25 stations in the Busan coastal region. The phytoplankton community and total phytoplankton biomass were strongly dependent on the discharge from the Nakdong River, and the high density of phytoplankton was related with the introduction of the Tsushima Warm Current (TWC), particularly in the thermohaline fronts of the fall season. The relationship between the salinity and nutrient (Dissolved inorganic nitrogen=DIN: R²=0.72, p<0.001 and Dissolved inorganic silicon=DSi: R²=0.78, p<0.001) highly correlated with the river discharge, implying that those nutrients have played a crucial role in the growth of diatom and cryptophyta. The total phytoplankton biomass was highest in the summer followed by autumn, spring, and winter. Diatom and cryptophyta species were dominant species during the four seasons. Additionally, there were strong positive correlations between Chlorophyll a and total phytoplankton biomass (R²=0.84, p<0.001), cryptophyta (R²=0.76, p<0.001) and diatom (R²=0.50, p<0.001), respectively. In particular, we found that there were significant differences in the nutrients, phytoplankton community compositions, and total phytoplankton biomass between the inner and the outer coastal region of Busan, depending on the amount of river discharge from the Nakdong River, particularly during rainy seasons. Therefore, the seasonal change of TWC and river discharge from the Nakdong River serve an important role in determining phytoplankton population dynamics in the Busan coastal region.