• Journal of the Korean Ceramic Society
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• v.40 no.2
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• pp.206-211
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• 2003

Effects of substrates and buffer layer upon the formation of crystalline phases and ferroelectricity of $YMnO_3$ thin films were investigated. The hexagonal $YMnO_3$ was easily formed on Si(100) while the mixed phases, hexagonal and orthorhombic $YMnO_3$, on $Pt(111)/TiO_2/SiO_2/Si$ substrate. When the $Y_2O_3$ buffer layer of 70 nm thick was inserted between the substrates and the $YMnO_3,$ the c-axis oriented hexagonal single phase formed on both substrates, Si(100) and $Pt(111)/TiO_2/SiO_2/Si$. The leakage current density of the hexagonal $YMnO_3$ thin films was lower than that consisting of mixed phases, hexagonal and orthorhombic. Furthermore the hexagonal $YMnO_3$ with c-axis preferred orientation showed the lowest leakage current density. The remnant polarization from a P-E hysteresis curve for the $YMnO_3$ formed on Si(100) was 0.14 without buffer layer and $0.24_{mu}C/cm^2$ for that with buffer layer. For the $Pt(111)/TiO_3/SiO_3/Si$ substrates, the specimen without $Y_2O_3$buffer layer did not show the hysteresis curve, while the buffer-layered has the remnant polarization of $1.14_{mu}C/cm^2$. It was concluded that the leakage current density and the ferroelectricity for the $YMnO_3$ thin films could be controlled by varying crystalline phases and their preferred orientation which depend on the kind of substrates and whether the $Y_2O_3$buffer layer exist or not.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.5
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• pp.767-773
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• 1998

In this study, we have investigated the distributions and killing effects of marine bacteria that tend to kill the red tide microalgae, C. polykikoides in the area of Masan bay from June to October, 1996. To summarize, C. polykikoides killing bacteria were detected at $10^2$ to $10^3$ cells/ml of seawater samples during the survey period, and the bloom was observed in September by containing $4.8\times10^3$cells/ml. It appears however that the number of these bacteria is decreased ($2.0\times10^2$cells/ml) in October, A total of 110 strains were isolated from seawater samples and seawater filtrate (pore size, 0.8 $\mu$m)-containing mixed culture of C. polykikoides in which the mixed culture was grown in f/2 medium. As results we have successfully isolated Micrococcus sp. LG-1 which decreased to less than 10cells/ml within 6days and 5days sfter inoculation of Micrococcus sp. LG-1 into the la9 and logarithmic growth phases of C. polykrikoides respectively. Therefore, it appears that inoculation of Micrococcus sp. LG-1 against the logarithmic C. polykrikoides is more effective than the lag growth phase, (n addition, the killing effects were increased in accordance with bacterial cell densities inoculated in a dose dependent manner. Especially, the filtrate of kitling bacterium culture (nore size, 0.2 $\mu$m) revealed a dramatic effect in which C. polykrikoides were decreased to less than 10 cells/mf of culture within 1 hr, 1,5 hrs, 1,5 hrs, 3.5 hrs. and 5,5 hrs after inoculations of the culture filtrate with concentration of $30\%,\;20\%,\;10\%,\;5\%$ and $2.5\%$, respectively. Moreover Micrococcus sp. LG-1 showed a selective specificity against C. polykrikoides and any other killing effects of Micrococcus sp. LG-1 were not observed against Alexandrium tamarense, Prorocentrum micans, Scrippsiella trochoidea. ana Gymnodinium sanguineum.

• Economic and Environmental Geology
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• v.52 no.3
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• pp.223-230
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• 2019

The calcination of oyster shells have been studied as the possible substitute for the limestone used as an absorbent of $SO_2$ gas. However, since pure shells can not be used in calcination process, some impurities are contained and the changes in the characteristics of the calcination products are expected. In this study, the surface characteristics of the calcination products are investigated by mineralogical analysis according to the contents of NaCl, which can be derived from sea water, and sediments on the surface of the shell as impurities. The marine sediments on the shells were mainly composed of quartz, albite, calcite, small amounts of amphibole and clay minerals such as ilite, chlorite and smectite. After calcination of oyster shells mixed with 0.2-4.0 wt% sediments at $900^{\circ}C$ for 2 hours, regardless of the dehydration, dehydroxylation, and phase change of these minerals at the lower temperature than this experiment, no noticeable changes were observed on the specific surface area of the calcined product. However, when mixed with 0.1 to 2.0 wt% NaCl, the specific surface area generally increases as compared with the shell sample before calcination. The specific surface area increases with increasing amount of salt, and then decreases again. This is closely related to the changes of surface morphology. As the amount of NaCl increases, the morphology of the surface is similar to that of gel. It changes into a slightly angular, smaller particle and again looks like gel with increasing amount of NaCl. Our results show that NaCl affects morphological changes probably caused by melting of some oyster shells, but may have different effects on the specific surface area of calcination product depending on the NaCl contents.

• Information Systems Review
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• v.25 no.4
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• pp.131-159
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• 2023

Recently, amidst the backdrop of the COVID-19 pandemic shifting towards an endemic phase, there has been a rise in discussions and debates about the future of the metaverse. Simultaneously, major metaverse platforms like Roblox have been launching services integrated with generative AI, and Apple's mixed reality hardware, Vision Pro, has been announced, creating new expectations for the metaverse. In this situation where the outlook for the metaverse is divided, it is crucial to diagnose the metaverse from an ecosystem perspective, examine its key ecological features, driving forces for development, and future possibilities for advancement. This study utilized Wang's (2021) Information Ecology Theory (IET) framework, which is representative of ecosystem research in the field of Information Systems (IS), to derive the Metaverse Industrial Ecosystem (MIE). The analysis revealed that the MIE consists of four main domains: Tech Landscape, Category Ecosystem, Metaverse Platform, and Product/Service Ecosystem. It was found that the MIE exhibits characteristics such as digital connectivity, the integration of real and virtual worlds, value creation capabilities, and value sharing (Web 3.0). Furthermore, the interactions among the domains within the MIE and the four characteristics of the ecosystem were identified as driving forces for the development of the MIE at an ecosystem level. Additionally, the development of the MIE at an ecosystem level was categorized into three distinct stages: Narrow Ecosystem, Expanded Ecosystem, and Everywhere Ecosystem. It is anticipated that future advancements in related technologies and industries, such as robotics, AI, and 6G, will promote the transition from the current Expanded Ecosystem level of the MIE to an Everywhere Ecosystem level, where the connection between the real and virtual worlds is pervasive. This study provides several implications. Firstly, it offers a foundational theory and analytical framework for ecosystem research, addressing a gap in previous metaverse studies. It also presents various research topics within the metaverse domain. Additionally, it establishes an academic foundation that integrates concept definition research and impact studies, which are key areas in metaverse research. Lastly, referring to the developmental stages and conditions proposed in this study, businesses and governments can explore future metaverse markets and related technologies. They can also consider diverse metaverse business strategies. These implications are expected to guide the exploration of the emerging metaverse market and facilitate the evaluation of various metaverse business strategies.

• Journal of Animal Science and Technology
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• v.47 no.6
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• pp.1001-1008
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• 2005

This study examined the effect of corn processing with varying rumen undegradable protein (RUP) on feed intake, milk yield, its composition and, blood characteristics in Holstein cows during the transitional period (21 days pre partum to 21 days post partum). Twenty Holstein cows were randomly assigned to four diets (five cows/diet), ground corn with 30 % RUP (GCR30), ground corn with 40 % RUP (GCR40), flaked corn with 30 % RUP (FCR30), and flaked corn with 40 % RUP (FCR40). The processed corn with varying RUP was fed in total mixed rations (TMR) to cows. Dry matter intake (DMI) was higher with 40 % RUP diet than with 30 % RUP diet, resulting in higher protein and energy intake by cows during pre and post partum (p＜0.05). However, it was not affected by corn processing during pre and post partum. Similarly milk yield was higher with 40 % RUP diet than with 30 % RUP diet. and milk yield was affected by corn processing at RUP 30 % level. Corn processing did not affected the milk fat and protein contents in dairy cows. The concentration of blood non esterified fatty acid (NEFA) were effected by RUP level with flaked corn, however, it was non-significant with RUP levels when given with ground corn. It is concluded that increasing RUP from 30 % to 40 % in iso-nitrogenous diet could increase milk yield in dairy cows during the transitional phase.

• Geophysics and Geophysical Exploration
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• v.13 no.1
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• pp.51-60
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• 2010

To determine subglacial topography and internal features of the Fourcade Glacier on King George Island in Antarctica, helicopter-borne and ground-towed ground-penetrating radar (GPR) data were recorded along four profiles in November 2006. Signature deconvolution, f-k migration velocity analysis, and finite-difference depth migration applied to the mixed-phase, single-channel, ground-towed data, were effective in increasing vertical resolution, obtaining the velocity function, and yielding clear depth images, respectively. For the helicopter-borne GPR, migration velocities were obtained as root-mean-squared velocities in a two-layer model of air and ice. The radar sections show rugged subglacial topography, englacial sliding surfaces, and localised scattering noise. The maximum depth to the basement is over 79m in the subglacial valley adjacent to the south-eastern slope of the divide ridge between Fourcade and Moczydlowski Glaciers. In the ground-towed profile, we interpret a complicated conduit above possible basal water and other isolated cavities, which are a few metres wide. Near the terminus, the GPR profiles image sliding surfaces, fractures, and faults that will contribute to the tidewater calving mechanism forming icebergs in Potter Cove.

• Journal of the Korean Chemical Society
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• v.38 no.12
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• pp.898-907
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• 1994

The solvent extraction of an inorganic trace mercury in sea water samples was studied using zinc diethyldithiocabamate $Zn(DDC)_2$ as chelating agent. The $Zn(DDC)_2$ which maintained the stability of DDC- in the acidic aqueous solution in the course of extraction was synthesized from NaDDC and $ZnSO_4$ in this laboratory. The trace of mercury(Ⅱ) was extracted at pH 3.0 from 100 ml of sea water into 10ml of chloroform containing 0.05 M $Zn(DDC)_2$ by shaking for 5 minutes. And from the organic phase, the $Hg(DDC)_2$ was back-extracted into 10ml of 1 to 1 mixed acid of each 3% (v/v) nitric acid and hydrochloric acid by shaking for 25 minutes. The mercury back-extracted was determined by a cold vapor atomic absorption spectrophotometry. The trace mercury(Ⅱ) was so successfully extracted that this procedure could be applied to its determination in the sea water. That is, the recoveries of mercury in two kinds of samples into which as given amount of Hg(Ⅱ) was spiked were 90.0% and 93.3%, respectively.

• Horticultural Science & Technology
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• v.19 no.4
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• pp.505-510
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• 2001

To improve germinability of carrot seeds of 'Inari', 'Mansan', 'Mussang', and 'Hongsim' cultivars, various levels of solid matrix priming (SMP) and the physiological changes of seeds associated with SMP were examined. As the ratio of water in a seed-Micro Cel E-water mix and priming duration increased, seed germinability enhanced. However, there was radicle protrusion during SMP in some cultivars, indicating the existence of cultivar different variations of the optimum conditions. The optimum ratio for a seed-Micro Cel E-water mix was 5 : 3 : 10.5. In this mix, the optimum durations for the treatment were 3 days for 'Mansan' and 5 days for other cultivars. SMP at $20^{\circ}C$ to $25^{\circ}C$ resulted in a higher germination percentage and a shorter $T_{50}$. Seeds absorbed water quickly within an hour and the percentage of moisture was stable at 43 to 49 after 24 hours of the treatment. Conductivity of the mix declined for the first 6 hours to $100{\mu}S{\cdot}cm^{-1}$ with little changes thereafter. On the other hand, the pH of the mixed increased slightly during the early phase, and then returned to the initial level as the treatment proceeded.

• Korean Journal of Veterinary Service
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• v.38 no.2
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• pp.127-136
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• 2015

A simultaneous determination method was developed for nine preservatives (benzoic acid, sorbic acid, dehydroacetic acid, methyl-, ethyl-, isopropyl-, propyl-, isobutyl- and butyl-parabens) in sausage by liquid chromatography with electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS). Each parameter was established by multiple reaction monitoring in negative mode. Separation was achieved on a phenyl-hexyl ($2.5{\mu}m$, $2.1{\times}150mm$, Waters) with A-20 mM ammonium acetate containing 0.1% acetic acid in water, B-Acetonitrile as mobile phase with gradient mode at a flow rate of 0.3 mL/min. The developed method was validated for specificity, linearity, accuracy and precision in sausages samples. Linearity was over 0.998 with calibration curve of the mixed standards. The mean recoveries from sausages fortified at the level of 2.0~10.0 mg/L were in range of 98.60~109.16% with RSDs lower than 8.93%. The limits of detection (LOD) and the limits of quantification (LOQ) were in the range between 0.0003~0.085 mg/L and 0.01~0.257 mg/L, respectively. Intra-day precision and inter-day precision were 0.45~6.16% and 2.81~13.33%, respectively. Using presently developed determination method, 33 field sausage samples from Gwangju city in Korea were screened over nine preservatives. As a result, no preservatives were detected in all samples.

• Journal of the Korean Chemical Society
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• v.58 no.2
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• pp.179-185
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• 2014

Commercial (S)-naproxen was racemized under strong basic condition. After checking the peak position of (R)- and (S)-naproxen by analysis the recemized naproxen, optical purity of 19 commercialized naproxens sold in 2013 in Korea were examined by chiral HPLC. The Chiralcel OD-H column, ChiralHyun-LE(S)-1 column and LUX-Cellulose-1 column were used as chiral stationary phases and the mixed eluent of hexane:isopropanol:acetic acid as 100:1:0.1 was used as a mobile phase with a flow rate of 1.0 mL/min. Each data was obtained from an average value of at least three different experiments for each sample and the relative standard deviation of them appeared very small. The average optical purity values obtained from three different chiral columns were very similar and the total average optical purity value (99.32%) of nineteen commercialized naproxens used in this study were larger than those of three years ago (98.17%).