• Journal of the Korean Electrochemical Society
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• v.23 no.2
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• pp.25-38
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• 2020

Photoelectrochemical water splitting has been considered as the most promising technology for generating hydrogen energy. Transition metal dichalcogenide (TMD) compounds have currently attracted tremendous attention due to their outstanding ability towards the catalytic water-splitting hydrogen evolution reaction (HER). Herein, we report the synthesis method of various transition metal dichalcogenide including MoS₂, MoSe₂, WS₂, and WSe₂ nanosheets as excellent catalysts for solar-driven photoelectrochemical (PEC) hydrogen evolution. Photocathodes were fabricated by growing the nanosheets directly onto Si nanowire (NW) arrays, with a thickness of 20 nm. The metal ion layers were formed by soaking the metal chloride ethanol solution and subsequent sulfurization or selenization produced the transition metal chalcogenide. They all exhibit excellent PEC performance in 0.5 M H₂SO₄; the photocurrent reaches to 20 mA cm^-2 (at 0 V vs. RHE) and the onset potential is 0.2 V under AM1.5 condition. The quantum efficiency of hydrogen generation is avg. 90%. The stability of MoS₂ and MoSe₂ is 90% for 3h, which is higher than that (80%) of WS₂ and WSe₂. Detailed structure analysis using X-ray photoelectron spectroscopy for before/after HER reveals that the Si-WS₂ and Si-WSe₂ experience more oxidation of Si NWs than Si-MoS₂ and Si-MoSe₂. This can be explained by the less protection of Si NW surface by their flake shape morphology. The high catalytic activity of TMDs should be the main cause of this enhanced PEC performance, promising efficient water-splitting Si-based PEC cells.

• Cartoon and Animation Studies
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• s.37
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• pp.197-219
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• 2014

, one of the Disney's animations, hit the 10 million audience mark for the first time in the history of animations released in Korea. not only raised the fever with its theme song, 'Let it go', as well as Elsa, Anna, and Olaf's character products but caused sensations in many ways. If so, we need to think about what kind of meaning did create in Korea to be so sensational. This study examines the value that Frozen intended to deliver and the meaning it generated by using Greimas actant model and semiotic square. From the actant model analysis on Anna and Elsa from , it was identified that Anna desired to recover her relationship with Elsa and to take summer back in Arendelle. Her desires can be interpreted as her love toward Elsa and people in Arendelle. Meanwhile, Elsa always desired freedom although she confined herself because of her ability to freeze. In other words, Elsa desired to free herself from her freezing ability by finding out how to control her ability. Such desires of Anna and Elsa were achieved by their actions of true love, and the solution of all the conflicts in was an action of true love. From the semiotic square analysis on the meaning of , it was found out that created past-oriented value with which characters tried to change their abnormal lives of the present into their normal lives of the past. The characters tried to change their present lives where freezing winter comes in the middle of summer, communication between the sisters is cut off, and people try to take advantage of the abnormal state deliberately, into the past when the sisters had a good relationship and the natural season of summer in Arendelle. The past-oriented value that tried to tell us is similar to our reality. In our reality with a lot of unbelievable news and unstable circumstances, we desire to go back to the past when we were filled with affection and hope even though our lives were tough and difficult. This sentiment must have contributed to the huge success of in Korea.

• Economic and Environmental Geology
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• v.38 no.2 s.171
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• pp.187-196
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• 2005

Structural sites which cations can occupy in garnet structure are centers of the tetrahedron, octahedron, and distorted cube sharing edges with the tetrahedron and octahedron. Among them, the size of cation occuping at tetrahedral site (the center of tetrahedron) is closely related with the size of a unit cell of garnet. Accordingly, garnet containing iron with relative large ionic radii in tetrahedral site can be considered as a promising matrix for the immobilization of the elements with large ionic radii, such as actinides in radioactive wastes. We synthesized several garnets with the batch composition of $Ca_{1.5}GdCe_{0.5}ZrFeFe_3O_{12}$, and studied their properties and phase relations under various conditions. Mixed samples were fabricated in a pellet form under a pressure of $200{\~}400{\cal}kg/{\cal}cm^2$ and were sintered in the temperature range of $1100\~1400^{\circ}C$ in air and under oxygen atmospheres. Phase identification and chemical analysis of synthesized samples were conducted by XRD and SEM/EDS. In results, garnet was obtained as the main phase at $1300^{\circ}C$, an optimum condition in this system, even though some minor phases like perovskite and unknown phase were included. The compositions of garnet and perovskite synthesized from the batch composition of $Ca_{1.5}GdCe_{0.5}ZrFeFe_3O_{12}$ were ranged $[Ca_{l.2-1.8}Gd_{0.9-1.4}Ce_{0.3-0.5}]^{VIII}[Zr_{0.8-1.3}Fe_{0.7-1.2}]^{VI}[Fe_{2.9-3.1}]^{IV}O_{12}$ and $Ca_{0.1-0.5}Gd_{0.0-0.8}Ce_{0.1-0.5}\;Zr_{0.0-0.2}Fe_{0.9-1.1}O_3$, respectively. Ca content was exceeded and Ce content was depleted in the 8-coordinated site, comparing to the initial batch composition. This phenomena was closely related to the content of Zr and Fe in the 6-coordinated site.

• Membrane Journal
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• v.21 no.2
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• pp.118-126
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• 2011

A method of light pre-irradiation, one of methods modifying hydrophobic surface to hydrophilic surface in a membrane, was proposed to overcome the drawback of previous methods such as blending, chemical treatment and post-irradiation, Process of membrane preparation in the study was comprised of 4 parts as follows: firstly process of precursor preparation to introduce hydrophilic nature under atmosphere and aqueous vapor by irradiating electron beam (EB), secondly process of dope solution preparation to cast on non-woven fabrics, thirdly process of casting to prepare membrane and finally process of coagulation in non-solvent to form porous structure. The merit of this method might show simple process as well as homogenous modification compared to previous methods. To carry it out, precursor was prepared by irradiating EB to powder PVDF at 75~125 K Gray dose. Precursor prepared was analyzed by FTIR, EDS and DSC to confirm the introduction of hydrophilic function and its mechanism. From their results, it was inferred I conformed that hydrophilic function was hydroxy1 and it was introduced by dehydrozenation. Hydrophilicity of membranes prepared was evaluated by contact angle (pristine PVDF : $62^{\circ}$, 125 K Gray-PVDF$13^{\circ}$). Porosity was evaluated by mercury intrusion method, simultaneously morpholoy and surface pore size were observed by SEM phothographs. The result showed the trend that more dose of EB led to smaller pore size and to lower porosity (pristine PVDF : 82%, 125 K Gray-PVDF : 63%). Trend of water permeability was similar to result above (pristine PVDF : 892 LMH, 125 K Gray-PVDF : 355 LMH).

• Applied Chemistry for Engineering
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• v.9 no.2
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• pp.207-213
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• 1998

On the basis of the previous study[1], miscibility were investigated and intermolecular interaction strength for the miscibility were relatively compared for the blends poly{2,2-(m-phenylene)-5,5'-bibenzimidazole}(PBI) with two aromatic polyimides (PIs) synthesized by another dianhydride. Aromatic PAAs were prepared by the reaction of condensation of two diamines, 4,4'-methylene dianiline(4,4'-MDA) and 4,4'-oxydianiline(4,4'-ODA) with 3,3',4,4'-diphenylsulfone tetracarboxylic dianhydride(DSDA) using DMAc, and then converted into PIs after curing. PBI/PAA blends were prepared by solution blending. Cast films or precipitated powders of the PBI/PAA blends were cared at a high temperature to transform into PBI/PIs blends. Miscibility and specific intermolecular interaction for miscibility in the blends were investigated, and compared with previous polyimide structures of PBI/PIs blends [1]. Two blends, PBI/DSDA+4,4'-MDA(Blend-V) and PBI/DSDA+4,4'-ODA(Blend-VI), were found miscible : the evidences were optically clear films, synergistic single composition dependent $T_g{\prime}s$, and frequency shifts of N-H stretching band as much as $39{\sim}40cm^{-1}$, and of C=O stretching band near 1730 and $1780cm^{-1}$, 5~6 and $3{\sim}4cm^{-1}$, respectively. The specific intermolecular interactions existing between PBI and PIs were relatively analyzed with the area(A) formed between the $T_g{\prime}s$ of the measured and that of the calculated by the Fox equation at all compositions, the ${\kappa}$ values in Gordon-Taylor equation obtained from the measured $T_g{\prime}s$, and differences of the frequency shifts in the functional N-H and carbonyl stretching band. From the results, the area(A) and the ${\kappa}$ values for Blend-V and VI were smaller than those for Blend-III and IV used in previous study[1]. Differences of the frequency shifts in the functional groups(N-H and C=O) also showed similar tendency. Thus, specific intermolecular interaction strength in terms of hydrogen bonding of PBI/PI blends is dependent upon chemical structures of PIs, that is, PIs it seems that $SO_2$ group in dianhydride(DSDA) has weaker hydrogen bond strength than those of C=O in BTDA. In other words, it implies that the former occupied bulk space than the latter due to the sterric effect.

• Journal of Distribution Science
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• v.10 no.1
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• pp.43-52
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• 2012

With the slowdown in environmental issues and the change of environmental consciousness, ecotourism is being discussed in various social fields. Ecotourism is being popularized for environmental protection, and now it is becoming a mainstream product from one of mass tourism. Ecotourism's emphasis on sustainable development in the tourism destination's society, economy, and environment, through ecotourism study and education, enable people to understand the core value of the ecological environment. 2011 was nominated as "the Year of World Forest" by the UN. In the recent years, forests are becoming increasingly important with their own values and functions in environment, economy, society, and culture. In particular, the global environmental issues caused by climate change are becoming an international agenda. Forests are the only effective solution for the carbon dioxide that causes global warming. Moreover, forests constitute a major part of ecotourism, and are now most used by ecotourists. For example, Korea, wherein 60% of the land is forest, attracts ecotourists. With the increasing interests in environment, the number of tourists visiting the ecosystem forest, which is highly valued for its conservation, is increasing significantly every year and is receiving considerable attention from the government. However, poor facilities in the forest ecotourism sites and improper market strategies are the reasons for the poor running of these sites. Furthermore, tourists' environmental awareness affects ecology environmental pollution or the optimization of forest ecotourism. In order to verify the relationships among tourist attractiveness, environmental consciousness, charm degrees of the attractions, and attitudes after tours, we established some scales based on existing research achievement. Then, using these scales, the researcher completed the questionnaire survey. From December 20, 2010 to February 20, 2011, after conducting surveys for 12 weeks, we finally obtained 582 valid questionnaires, from a total of 700 questionnaires, that could be used in statistical analysis. First, for the method of research and analysis, the researcher initially applied the Cronbach's (Alpha) for verifying the reliability, and subsequently applied the Exploratory factor analysis for verifying the validity. Second, in order to analyze the demographics, the researcher makes use of the Frequency analysis for the AMOS, measurement model, structural equation model computing, and also utilizes construct validity, convergent validity, discriminant validity, and nomological validity. Third, for the analysis of the ecotourists' environmental consciousness, impacts on tourist attractiveness, charm degrees of the attractions, and attitudes after the tour, the researcher uses AMOS 19, with the path analysis and equation of structure. After the research, researchers found that high awareness of natural protection lead to high tourist motivation and satisfaction and more positive attitude after the tour. Moreover, this research shows the psychological and behavioral reactions of the ecotourists to the ecotourist development. Accordingly, environmental consciousness does not affect the tourist attractiveness that has been interpreted as significant. Furthermore, people should focus on the change of natural protection consciousness and psychological reaction of ecotourists while ensuring the sustainable development of ecotourists and developing some ecotourist programs.

• Cartoon and Animation Studies
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• s.44
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• pp.333-361
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• 2016

In general, content business companies include animation industry can have benefits, which they have higher incomes when they obtain wider markets. Therefore, they pursue to have diverse windows for content distribution or to reach the foreign markets for dealing their content products with potential customers. It have the greatest value. They can re-invest the incomes to produce their new products, and they can enhance the international competitiveness of their next products. As the results, the companies can have more incomes and wider markets in next business, and it will be the effectiveness of the good cycle of the animation industry. Animation industry has being undergone of its structure changes, more economical chances and viewers' attitudes changes through the all over the industry because of the acceptance of new digital technology. To response the changes or have the new chances from the changes, they should to review the existing system and the law concerned with the animation business as well as having the diverse new plans for supporting the industry like a construction of the online marketplace of Korean animation. It would make the Korean animation companies to meet foreign customers easily by making lower the entrance barrier of the foreign markets. Current Korean government needs to estimate the value of the Korean animation accurately and objectively by concerning its surroundings to support efficiently. However, it is very difficult to estimate the value of the content rightly because of its' intangible and subjective matter. For this, they should analyze the all the data of the information of the Korean animation content by accumulate, open to the public and manage. So if the government makes online marketplace for the Korean animation, which all the Korean animation companies get in, it would be a solution of estimating the value of the Korean animation rightly. In addition, it will be used as the role of archive of the government to lead the industry successfully. As a point of the small size of the Korean animation companies, they are government dependable because of its low budget, so they strongly expect the government to do the right role as the unique knowledge distributor. Therefore, the Korean animation online marketplace would make not only big companies, but also small companies to have the chances to increase the value of their content in the global markets by themselves without economic burdens.

• Journal of the Mineralogical Society of Korea
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• v.22 no.1
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• pp.23-34
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• 2009

The adsorption of iodide on untreated bentonite and bentonites modified with organic cation (i.e., hexadecylpyridinium chloride monohydrate ($HDP^+$)) was investigated, and the organobentonites were characterized using uptake measurements, ${\mu}$-XRD, and electrophoretic mobilities measurement. Uptake measurements indicate that bentonite has a high affinity for $HDP^+$. Our ${\mu}$-XRD study indicates that organobentonites significantly expanded in basal spacing and organic cations were substantially intercalated into the interlayer spaces of bentonite. The electrophoretic mobility indicates that organobentonite tht is modified with organic cations in excess of the CEC of bentonite is completely different from untreated bentonite in the surface charge distribution. We found significant differences in adsorption capacities of iodide depending on the bentonite properties as follows: iodide adsorption capacities were 439 mmol/kg for the bentonite modified with $HDP^+$ at an equivalent amount corresponding to 200% of the CEC of bentonite whereas no adsorption of iodide was observed for the untreated bentonite. The molecular environments of iodine adsorbed on organobentonites were further studied using I K-edge and $L_{III}$-edge x-ray absorption spectroscopy (XAS). The X-ray absorption near-edge structure (XANES) of iodine spectra from organobentonites was similar to that of KI reference solution. Linear combination fitting of EXAFS data suggests the fraction of iodine reacted with the organic compound increased with increasing loading of the organic compound on organobentonites. In this study, we observed significant differences in the adsorption environments of iodide depending on the modified property of bentonite and suggest that an organobentonite has potential as reactive barrier material around a nuclear waste repository containing anionic radioactive iodide.

• Journal of dental hygiene science
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• v.7 no.1
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• pp.25-30
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• 2007

The objective of this study is to suggest the utilization of educated dental hygienist as the solution to the problem of supply and demand in dental clinics that has been brought up recently. Through document research and National Health Personnel Licensing Examination Board homepage, we estimated the number of dental hygienist and the condition of employment as well as gotten a grasp of the current activities carried out by dental hygienists. Furthermore, through discussion of researchers, suggested reform bills to guarantee and extend the work of dental hygienists as well as to train dental assistant. The findings were as follows: As the result of the estimation of dental hygienist, in the year 2009, two dental hygienists structure will be formed in each dental clinic. Currently the practice ratio of non-law activities of dental hygienists is high and in order to increase the practical use of dental hygienists, there is a need to reform bills that guarantee and extend the work of dental hygienists. In order to train new labors, there is a need for cautious consideration to distinguish the activities of existing trained labors, reforming of bills, and considering from various other sectors. From present point of view, solving the problem of existing trained dental hygienists, researching for the plan of utilizing dental hygienists and carrying it into practice must be the priority.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.1
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• pp.52-60
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• 2016

The biological activity of polysaccharide is greatly influenced by polysaccharide structure and molecular distribution. Here, we developed a rapid and convenient isolation method for fractionating polysaccharides with different characteristics and optimized it using a polysaccharide mixture from Korean persimmon leaves. A crude polysaccharide mixture, persimmon leaves-enzyme (PLE) fraction, was isolated from persimmon leaves digested with pectinase and ethanol precipitation. The PLE fraction was further fractionated with a serially diluted ethanol solution (ethanol : deionized water=4:1, 2:1, 1.5:1, 1:1, and 0.5:1) to produce 10 subfractions (five precipitate fractions labeled from PLE-4 to PLE-0.5 and five supernatant fractions labeled from PLE-4S to PLE-0.5S). HPLC analysis indicated that PLE-4 and -2 consisted of diverse polysaccharides, whereas PLE-1.5, -1, and -0.5 contained high molecular weight (MW) polysaccharides. The fractions from PLE-4 to PLE-1 were mostly composed of 13 different characteristic sugars in rhamnogalacturonan (RG) I and II, and the sugars contained an arabino-${\beta}$-3,6-galactan moiety. However, PLE-0.5 did not contain RG-II or ${\beta}$-arabino-3,6-galactan. Treatment of macrophages with fractions PLE-1.5S and PLE-1S led to a $10{\mu}g/mL$ increase in interleukin (IL)-6 production, whereas treatment with PLE-4S and PLE-2S fractions composed of low MW polysaccharides resulted in reduced levels of IL-6. These results indicate that this isolation method may be useful for the rapid and convenient fractionation of bioactive RGs from polysaccharide mixtures with various properties.