• Applied Chemistry for Engineering
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• v.33 no.5
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• pp.496-501
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• 2022

In this study, an anode material for lithium secondary batteries was manufactured using petroleum-based residual oil, which is a petroleum refining by-product. Among petroleum-based residual oils, pyrolysis fuel oil (PFO), fluidized catalyst cracking-decant oil (FCC-DO), and vacuum residue (VR) were used as carbon precursors. The physicochemical characteristics of petroleum-based residual oil were confirmed through Matrix-assisted laser desorption/ionization Time-of-Flight (MALDI-TOF) and elemental analysis (EA), and the structural characteristics of anode materials manufactured from residual oil were evaluated using X-ray crystallography (XRD) and Raman spectroscopic techniques. VR was found to contain a wide range of molecular weight distributions and large amounts of impurities compared to PFO and FCC-DO, and PFO and FCC-DO exhibited almost similar physicochemical characteristics. From the XRD analysis results, carbonized PFO and FCC-DO showed similar d₀₀₂ values. However, it was confirmed that FCC-DO had a more developed layered structure than PFO in Lc (Length of a and c axes in the crystal system) and La values. In addition, FCC-DO showed the best cycle characteristics in electrochemical characteristics evaluation. According to the physicochemical and electrochemical results of the petroleum-based residual oil, FCC-DO is a better carbon precursor for a lithium secondary battery than PFO and VR.

• Analyses & Alternatives
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• v.2 no.1
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• pp.31-69
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• 2018

This study examines the role of science in resolving trade disputes. After the Great East Japan Earthquake of 11 March 2011 that not only jeopardized the people of Japan, but also put the safety of an entire region at risk, the Republic of Korea (Korea) has imposed import bans as well as increased testing and certification requirements for radioactive material on Japanese food products. Japan has challenged these restrictions at the World Trade Organizations Dispute Settlement Body (DSB). This study aims to explain how international trade agreements and previous DSB rulings have dealt with different scientific viewpoints provided by confronting parties. In doing so, it will contrast the viewpoints espoused by Korean and Japanese representatives, and then analyzes the most similar case studies previously ruled on by the DSB, including the case of beef hormones and the case of genetically modified crops including biotech corn, both between the United States and the European Communities (EC). This study finds that science is largely subordinate to national interests in the case of state decision-making within the dispute settlement processes, and science has largely been relegated to a supportive role. Due to the ambiguity and lack of truly decisive decisions in the Appellate Body in science-based trade disputes, this study concludes that the Appellate Body avoids taking a firm scientific position in cases where science is still inconclusive in any capacity. Due to the panel's unwillingness to establish expert review boards as it has the power to do, instead favoring an individual-based system so that all viewpoints can be heard, it has also developed a system with its own unique weaknesses. Similar to any court of law in which each opposing party defends its own interests, each side brings whatever scientific evidence it can to defend its position, incentivizing them to disregard scientific conclusions unfavorable to their position. With so many questions that can arise, combined with the problems of evolving science, questions of risk, and social concerns in democratic society, it is no wonder that the panel views scientific information provided by the experts as secondary to the legal and procedural issues. Despite being ruled against the EC on legal issues in two previous cases, the EC essentially won both times because the panel did not address whether its science was correct or not. This failure to conclusively resolve a debate over whose science is more scientific enabled the EC to simply fix the procedural issues, while continuing to enforce trade restrictions based on their scientific evidence. Based on the analysis of the two cases of disputes, Korea may also find itself guilty of imposing an unwarranted moratorium on Japan's fish exports, only to subsequently pass new restrictions on labelling and certification requirements because Japan may have much scientific evidence at its disposal. However, Korea might be able to create enough uncertainty in the panel to force them to rule exclusively on the legal issues of the case. This will then equip Korea, like the EC in the past, with a way of working around the ruling, by changing whatever legal procedure they need to while maintaining some, if not most, of its restrictions when the panel fails to address its case on scientific grounds.

• Journal of agriculture & life science
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• v.50 no.5
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• pp.51-60
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• 2016

This study was selected drought tolerant plants, by observing the physiological characteristics and biochemical materials from the 9 kinds of the Compositae plants. After selecting plants of the similar size, and then drought stress was induced by the irrigation stopping. Survival rates, chlorophyll values, relative water content(RWC), excised-leaf water loss(ELWL), proline, reducing sugar were measured after 30 days of stopping irrigation. The species that had high rates of survival were Ainsliaea acerifolia Sch. Bip, Aster koraiensis, Aster scaber, Dendranthema zawadskii(S), however other 5 species were dead. The remaining factors have been determined based on plant species showed a higher survival rate. However, chlorophyll content showed high values in A. acerifolia, A.altaicus var. uchiyamae, A. koraiensis, and will have been determined that has no correlation with survival rates, except for A. acerifolia and A. koraiensis. On the other hand, A. scaber, A. acerifolia, A. koraiensis were determined to be relatively high drought tolerant plants in RWC, ELWL, proline, reducing sugar, it showed a similar correlation with survival rate. As a result of 9 kinds of the Compositae plants A. scaber, A. acerifolia, A. koraiensis were considered relatively higher drought tolerant plants.

• Journal of the Korean Society of Food Culture
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• v.25 no.3
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• pp.350-356
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• 2010

When extracts of KMG (Korean mountain ginseng) leaf tea and fermented KMG leaf tea were compared, the fermented KMG leaf tea extract showedhigher activity at each stage of density. Among the material groups, the KMG extract hadthe least profound SOD-like activity, and similar SOD-like activities were noted in the fermented KMG, KMG leaf tea, and fermented KMG leaf tea extracts. With regard to nitrite scavenging ability at a pH of 1.2, the KMG, fermented KMG, and KMG leaf tea groups exhibited similar results, and at pH 3.0, the KMG and KMG leaf tea extract groups exhibited more profound nitrite scavenging ability compared to the fermented groups. In the case of HeLa cell treatments, the KMG and fermented KMG leaf tea extracts exhibited cancer cell propagation restraint rates in excess of 30%, at a density of 1 mg/mL. And MCF-7 cells treated with fermented KMG and KMG leaf tea showedsimilar propagation restraint rates at more than 27% of cancer cells, at a density of 1 mg/mL. Among the materials, the KMG extract hadthe lowest cancer cell propagation restraint rate at 21%, and the fermented KMG leaf tea extract had the highest rate at more than 70%.

• Phonetics and Speech Sciences
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• v.15 no.3
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• pp.27-35
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• 2023

This study aimed to investigate the effect of Chinese on the production of Korean rhythm. Korean and Chinese are typologically classified into different rhythmic categories; because of this, the phonological properties of Korean and Chinese are similar and different at the same time. As a result, Chinese can exert both positive and negative influences on the realization of Korean rhythm. To investigate the influence of the rhythm of the native language of L2 learners on their target language, we conducted an acoustic analysis using acoustic metrics like of the speech of 5 Korean native speakers and 10 advanced Chinese Korean learners. The analyzed material is a short paragraph of five sentences containing a variety of syllable structures. The results showed that KS and CS rhythms are similar in %V, VarcoV, and nPVI_S. However, CS, unlike KS, showed characteristics closer to those of a stress-timed language in the values of %V and VarcoV. There was also a significant difference in nPVI_V values. These results demonstrate a negative influence of the native language in the realization of Korean rhythm. This can be attributed to the fact that all vowels in Chinese sentence are not pronounced with the same emphasis due to neutral tone. In this sense, this study allowed us to observe influences of L1 on L2 production of rhythm.

• Journal of Korean Tunnelling and Underground Space Association
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• v.26 no.3
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• pp.209-222
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• 2024

The Earth Pressure Balance (EPB) shield Tunnel Boring Machine (TBM) is widely used for underground tunnel construction for its advantages, such as eliminating the need for additional facilities compared to the slurry shield TBM, which requires Slurry Treatment Plant (STP). During EPB shield TBM excavation, a soil conditioning technique is employed to enhance the physical properties of the excavated soil by injecting additives, thus broadening the range of applicable ground conditions to EPB shield TBMs. This study explored the use of xanthan gum, a type of biopolymer, as an alternative to the commonly used polymer additive. Biopolymers, derived from biological sources, are fully biodegradable. In contrast to traditional polymers such as polyacrylic acid, which contain environmentally harmful components, xanthan gum is gaining attention as an eco-friendly material due to its minimal toxicity and environmental impact. Test conditions with similar workability were established through slump tests, and the rheological characteristics were assessed using a laboratory pressurized vane shear test apparatus. The experiments demonstrated that, despite exhibiting similar workability, the peak strength in the flow curve decreased with increasing the content of xanthan gum. Consequently, a correlation between the xanthan gum content and peak strength was established. Replacing the traditional polymers with xanthan gum could enable stable EPB shield TBM operation by reducing equipment load, in addition to offering environmental benefits.

• Korean Journal of Heritage: History & Science
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• v.57 no.3
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• pp.70-88
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• 2024

Syenite is the name of a rock that has been used since ancient Roman period, but it is not widely distributed worldwide, and cases of its use as a material for Korean stone cultural heritages are very rare. However, the Three-story Stone Pagoda in Beomhak-ri of Sancheong, is composed of syenite, and each stone property has very similar rock phases, mineral compositions, grain sizes, colors and magnetic susceptibilities, indicating that they are all stones of the same rock series. Outcrops of syenite are relative widely distributed in the Beomhak-ri area, and it was mined for use as building stones until recently. This rock is almost identical in overall colors, occurrences, and mineralogical and petrological characteristics to that of the stone pagoda, and the geochemical evolution trends of the rocks are also very similar. In addition, numerous quarrying traces were identified in the same rock around the Beomhaksaji Temple site. In this way, the original stone properties of the Beomhak-ri Stone Pagoda were determined to be syenite because precise petrological and geochemical analysis and provenance interpretation was possible, the syenite was distributed around the temple site, and ancient quarrying traces were scattered in the same rocks. Therefore, it can be interpreted that the Beomhak-ri Stone Pagoda was processed and constructed using self-sufficient stone materials from the temple site area.

• Journal of Ginseng Research
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• v.22 no.4
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• pp.274-283
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• 1998

It has generally been accepted that quality of ginseng should be determined not by the content of a single component but by composition and balance of total active principles. However, there still can be an exception with a product in which a given ginsenoside is used for the treatment of a specific disease. Although ginsenosides have been regarded to be major active components of ginseng and employed as index components for the quality control, it does not consistent with the traditional concept on ginseng quality creterion; main root has been more highly appreciated than the lateral or fine root. Content of ginsenosides in the lateral or fine root is much higher than that in main root. However, the ratio of protopanaxadiol (PD) and protopanaxatriol (PT) saponins existing in various part of ginseng root is greatly different. The ratio of PD/PT saponins in main root is well balanced but the thinner the root is the higher the ratio. Thus far, a total of 34 different kinds of ginsenosides have been isolated from Korean (red) ginseng, and their pharmacological activities were elucidated partly. Interestingly, different ginsenoside shows similar or contrary effects to each other in biological systems, thus indicating the significance of absolute content of single ginsenoside as well as compositional patterns of each ginsenoside. Therefore, pharmacological activities of ginseng should be determined as a wholly concept. In these regards, standardization of ginseng material (fresh ginseng root) should be preceded to the standardization of ginseng products because ginsenoside content and non-saponin active principles such as polysaccharides and nitrogen (N)-containing compound including proteins are significantly different from part to part of the root. In other words, the main root contains less ginsenosides than other lateral or fine roots. Contents of polysaccharides and N-containing compound in main root is higher. However, the quality control of ginseng products focused on non-saponin compounds has limitation in applying to the analytical method, because of the difficult chemical analysis of these compounds. Content of ginsenosides, and ratios of PD/PT and ginsenoside Rb,/Rg, are inversely proportional to the diameter of ginseng root. Therefore, these can be served as the chemical parameters for the indirect method of evaluating from what part of the root does the material originate. Furthermore, contents of polysaccharides and N-containing compounds show inverse relationship to saponin content. Therefore, it seems that index for analytical chemistry of saponin can be applied to the indirect method of evaluating not only saponin but also non-saponin compounds of ginseng. From these viewpoints, it is strongly recommended that quality of ginseng or ginseng products be judged not only by the absolute content of given ginsenoside but also by varieties and compositional balance of ginsenosides, including contents of non-saponin active principles.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.7
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• pp.941-946
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• 2010

For the long-term goal of using peanut sprouts as a functional food material, the total polyphenol content and the antioxidant activity of methanol extracts were examined with use of 9 day-old peanut sprouts and peanuts collected in Chungbuk, Gyeongbuk and Jeonbuk provinces of Korea, China and Vietnam. The polyphenol levels in the sprout extracts were higher than those of the peanut extracts. The phenolic content of the Gyeongbuk peanut sprout extract (20.4 mg/g) was the highest of the tested samples. After 9 days of germination the peanut sprout extracts had higher activities than those of the peanut extracts. In particular, the activity of Gyeongbuk peanut sprout extract was the highest (37.67% at a concentration of $200\;{\mu}L/mL$), and its reducing power demonstrated a similar trend. The DPPH radical scavenging activities were measured for methanol extracts of cotyledon, root and stem of Gyeongbuk peanut sprouts; the highest (90.96% at a concentration of $200\;{\mu}L/mL$) was the activity of cotyledon. ABTS radical scavenging and $\beta$-carotene bleaching activities also were higher in the cotyledon extract than in those of the root or the stem. The resveratrol content was higher in the Gyeongbuk peanut sprout extract than in the Gyeongbuk peanut extract ($15.05\;{\mu}g/g $and $1.42\;{\mu}g/g$, respectively). These results suggest that peanut sprouts potentially could be used as a functional food material exhibiting antioxidant effects.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.254-255
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• 2012

Interest in nano-crystalline silicon (nc-Si) thin films has been growing because of their favorable processing conditions for certain electronic devices. In particular, there has been an increase in the use of nc-Si thin films in photovoltaics for large solar cell panels and in thin film transistors for large flat panel displays. One of the most important material properties for these device applications is the macroscopic charge-carrier mobility. Hydrogenated amorphous silicon (a-Si:H) or nc-Si is a basic material in thin film transistors (TFTs). However, a-Si:H based devices have low carrier mobility and bias instability due to their metastable properties. The large number of trap sites and incomplete hydrogen passivation of a-Si:H film produce limited carrier transport. The basic electrical properties, including the carrier mobility and stability, of nc-Si TFTs might be superior to those of a-Si:H thin film. However, typical nc-Si thin films tend to have mobilities similar to a-Si films, although changes in the processing conditions can enhance the mobility. In polycrystalline silicon (poly-Si) thin films, the performance of the devices is strongly influenced by the boundaries between neighboring crystalline grains. These grain boundaries limit the conductance of macroscopic regions comprised of multiple grains. In much of the work on poly-Si thin films, it was shown that the performance of TFTs was largely determined by the number and location of the grain boundaries within the channel. Hence, efforts were made to reduce the total number of grain boundaries by increasing the average grain size. However, even a small number of grain boundaries can significantly reduce the macroscopic charge carrier mobility. The nano-crystalline or polymorphous-Si development for TFT and solar cells have been employed to compensate for disadvantage inherent to a-Si and micro-crystalline silicon (${\mu}$-Si). Recently, a novel process for deposition of nano-crystralline silicon (nc-Si) thin films at room temperature was developed using neutral beam assisted chemical vapor deposition (NBaCVD) with a neutral particle beam (NPB) source, which controls the energy of incident neutral particles in the range of 1~300 eV in order to enhance the atomic activation and crystalline of thin films at room temperature. In previous our experiments, we verified favorable properties of nc-Si thin films for certain electronic devices. During the formation of the nc-Si thin films by the NBaCVD with various process conditions, NPB energy directly controlled by the reflector bias and effectively increased crystal fraction (~80%) by uniformly distributed nc grains with 3~10 nm size. The more resent work on nc-Si thin film transistors (TFT) was done. We identified the performance of nc-Si TFT active channeal layers. The dependence of the performance of nc-Si TFT on the primary process parameters is explored. Raman, FT-IR and transmission electron microscope (TEM) were used to study the microstructures and the crystalline volume fraction of nc-Si films. The electric properties were investigated on Cr/SiO2/nc-Si metal-oxide-semiconductor (MOS) capacitors.