• The Journal of Engineering Geology
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• v.33 no.1
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• pp.85-103
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• 2023

The in-situ remediation of a solidified stratum containing a large amount of fine-texture material like clay or organic matter in contaminated soil faces limitations such as increased remediation cost resulting from decreased purification efficiency. Even if the soil conditions are good, remediation generally requires a long time to complete because of non-uniform soil properties and low permeability. This study assessed the remediation effect and evaluated the field applicability of a methodology that combines pneumatic fracturing, vacuum extraction, and plasma blasting (the PPV method) to improve the limitations facing existing underground remediation methods. For comparison, underground remediation was performed over 80 days using the experimental PPV method and chemical oxidation (the control method). The control group showed no decrease in the degree of contamination due to the poor delivery of the soil remediation agent, whereas the PPV method clearly reduced the degree of contamination during the remediation period. Remediation effect, as assessed by the reduction of the highest TPH (Total Petroleum Hydrocarbons) concentration by distance from the injection well, was uncleared in the control group, whereas the PPV method showed a remediation effect of 62.6% within a 1 m radius of the injection well radius, 90.1% within 1.1~2.0 m, and 92.1% within 2.1~3.0 m. When evaluating the remediation efficiency by considering the average rate of TPH concentration reduction by distance from the injection well, the control group was not clear; in contrast, the PPV method showed 53.6% remediation effect within 1 m of the injection well, 82.4% within 1.1~2.0 m, and 68.7% within 2.1~3.0 m. Both ways of considering purification efficiency (based on changes in TPH maximum and average contamination concentration) found the PPV method to increase the remediation effect by 149.0~184.8% compared with the control group; its average increase in remediation effect was ~167%. The time taken to reduce contamination by 80% of the initial concentration was evaluated by deriving a correlation equation through analysis of the TPH concentration: the PPV method could reduce the purification time by 184.4% compared with chemical oxidation. However, the present evaluation of a single site cannot be equally applied to all strata, so additional research is necessary to explore more clearly the proposed method's effect.

• Proceedings of the KACD Conference
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• 2008.05a
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• pp.169-176
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• 2008

The purpose of this study was to evaluate the effect of thickness, filling methods and curing methods on the polymerization of dual cured core materials by means of microhardness test. Two dual cured core materials, MultiCore Flow (Ivoclar Vivadent AG, Schaan, Liechtenstein) and Bis-Core (Bisco Inc., Schaumburg, IL, USA) were used in this study. 2 mm (bulky filled), 4 mm (bulky filled), 6 mm (bulky and incrementally filled) and 8 mm (bulky and incrementally filled)-thickness specimens were prepared with light cure or self cure mode. After storage at $37^{\circ}C$ for 24 hours, the Knoop hardness values (KHN) of top and bottom surfaces were measured and the microhardness ratio of top and bottom surfaces was calculated. The data were analyzed using one-way ANOVA and Scheffe multiple comparison test, with ${\alpha}=0.05$. The effect of thickness on the polymerization of dual cured composites showed material specific results. In 2, 4 and 6 mm groups, the KHN of two materials were not affected by thickness. However, in 8 mm group of MultiCore Flow, the KHN of the bottom surface was lower than those of other groups (p < 0.05). The effect of filling methods on the polymerization of dual cured composites was different by their thickness or materials. In 6 mm thickness, there was no significant difference between bulk and incremental filling groups. In 8 mm thickness, Bis-Core showed no significant difference between groups. However, in MultiCore Flow, the microhardness ratio of bulk filling group was lower than that of incremental filling group (p < 0.05). The effect of curing methods on the polymerization of dual cured composites showed material specific results. In Bis-Core, the KHN of dual cured group were higher than those of self cured group at both surfaces (p < 0.05). However, in MultiCore Flow, the results were not similar at both surfaces. At the top surface, dual cured group showed higher KHN than that of self cured group (p < 0.05). However, in the bottom surface, dual cured group showed lower value than that of self cured group (p < 0.05).

• Journal of Life Science
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• v.33 no.2
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• pp.138-148
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• 2023

This study compared and analyzed the antioxidant activities of various organic solvent fractions from the leaves and roots of Peucedanum insolens Kitagawa. For this study, the dried leaves and roots of P. insolens Kitagawa were first extracted using 70% ethanol. The extracts were sequentially sub-fractionated in the order of hexane, chloroform, ethyl acetate, n-butanol, and water. The results revealed that the distribution of total phenolic contents by organic solvent fractions showed the same pattern in both the leaves and roots, with the highest in the ethyl acetate fraction (101.1±1.0 mg vs 71.2±3.4 mg of GAE/mg), but the lowest content in the hexane fraction (9.5±0.2 mg vs 7.5±2.1 mg of GAE/mg). The distribution of total flavonoid content in the organic solvent fractions showed the same pattern as that of total phenolic content. The results of DPPH, ABTS, and FRAP assays showed that the leaf and root extracts exhibited free radical scavenging activity in the same pattern, particularly, the ethyl acetate fraction had the highest activity. These results indicate that not only the roots of P. insolens Kitagawa but also the leaves possess potential substances that exhibit strong antioxidant activity. Significant correlations (R=0.903, p<0.0001, DPPH radical; R=0.891, p<0.001, ABTS radical; R=0.745, p<0.05, FRAP radical) between total phenolics and radical scavenging activities, but also significant correlations (R=0.867, p<0.001, DPPH vs. ABTS radicals; R=0.882, p<0.0001, DPPH vs. FRAP radicals; R=0.973, p<0.0001, ABTS vs. FRAP radicals) between radical scavenging activities were found in the organic solvent fractions. Therefore, as in the roots of P. insolens Kitagawa, the leaves possess strong antioxidant capacity and can be used as the main antioxidant material.

• Journal of Life Science
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• v.33 no.2
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• pp.169-175
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• 2023

As a protective defensive mechanism against ultraviolet (UV) light exposure in skin tissue, melanocytes produce the pigment melanin. Tyrosinase plays a key role in melanin production in melanocytes. However, the overproduction of melanin can lead to lesions, such as freckles and dark spots. Thus, it is clinically important to find a modulating molecule to control melanogenesis by regulating tyrosinase expression and/or activity. It is known that catechin, a plant flavonoid, can reduce melano- genesis through the downregulation of tyrosinase expression. Here, we tested whether catechin derivatives isolated from the stem bark of Ulmus parvifolia have an effect on melanin production by regulating tyrosinase in mouse melanoma cells and in vitro mushroom tyrosinase. The catechin derivatives used in this study included C5A, C7A, C7G, and C7X. Treatments using these catechin derivatives reduced melanin production in mouse melanoma B16F10 cells in which melanogenesis was stimulated by α-MSH. Notably, the anti-melanogenic effects of catechin derivatives were similar to those of kojic acid, a well-known anti-melanogenic molecule. Both C5A and C7A directly inhibited the activity of tyrosinase isolated from mushrooms in vitro. Furthermore, our in silico computational simulation showed that these two compounds were expected to bind to the active site of tyrosinase, which is similar to kojic acid. In addition, all four catechin derivatives reduced tyrosinase protein expression. In summary, our results showed that catechin derivatives can reduce melanogenesis by regulating tyrosinase activity or expression. Thus, this study suggests that catechin derivatives isolated from U. parvifolia can be novel modulators of melanin production.

• Journal of Korea Port Economic Association
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• v.39 no.1
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• pp.131-147
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• 2023

Gwangyang Port Marine Industry Cluster is the only marine industry cluster in Korea that is currently in operation, but despite the implementation of various revitalization policies since its opening, the occupancy rate has been low so far. Accordingly, this study aims to identify the constraints of the current system that hinder the inducement of tenant companies and to suggest revitalization measures. For this purpose, this study analyzed the current status of research and development(R&D) projects in the port, shipping and logistics sector, which is a core industry of the Gwangyang Port Marine Industry Cluster. And a survey was conducted on companies with potential to move in. As a result, the proportion of R&D in the core industry sectors is lower than in other sectors, and most of R&D projects are being carried out mainly by small and medium-sized enterprises. In addition, the low need for port facilities and low accessibility to Gwangyang Port were derived as constraints. Considering the results, this study suggests four revitalization measures to induce tenant companies as follows. First, it is necessary to expand the scope of core industries from the current shipping, ports, and logistics to the entire maritime and fisheries, so that companies performing R&D in the industry can move in. Second, the industry code currently specified as a qualification need to be revised to include both the industry of the enterprise carrying out R&D projects and the core industry. Therefore, this study suggests an expanded industry code list that can replace current list. Third, a transition of tenant recruitment system from the regular system(once or twice a year) to the occasional system is proposed so that companies can move in flexibly when demand arises. Finally, in order to overcome geographically low accessibility, technology development support projects specialized in R&D that prospective tenant companies actually need are needed rather than financial support.

• Journal of the Korea Organic Resources Recycling Association
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• v.31 no.3
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• pp.55-64
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• 2023

This batch experiment was conducted to investigate the patterns of major plant nutrients in the leachates from the soil that was incorporated with rice hull biochar adjusted pH with dry fish powder utilizing rice hull biochar for loading the soil microorganisms. The rice hull biochar adjusted pH between 6.0 and 7.0, and the mixture ratio of rice hull biochar and dry fish powder was 4:6. The treatments consisted of three; the soil incorporated with rice hull biochar non-adjusted pH with dry fish powder as control (RB + DF), the soil incorporated with rice hull biochar adjusted pH by pyroligneous acid solution and dry fish powder (RBP+DF), and the soil incorporated with rice hull biochar adjusted pH by citric acid solution and dry fish powder (RBC+DF). NH₄-N, NO₃-N, PO₄-P, and K concentrations in the leachates were analyzed during incubation. The accumulated NH₄-N and PO₄-P concentrations in the leachates from the RBC+DF treatment were the highest during leaching periods. The highest accumulated NO₃-N and K concentrations in the leachates from the RBP+DF treatment were observed. It observed that NH₄-N and PO₄-P were more released in the adjusted citric acid solution, but NO₃-N and K were less released than those in the pyroligneous acid solution due to their low absorption capacity. Furthermore, it is necessary to investigate crop growth responses to the soil incorporated with adjusted pH rice hull biochar and dry fish powder for loading soil microorganisms.

• Journal of the Daesoon Academy of Sciences
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• v.42
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• pp.109-141
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• 2022

As many perhaps already know, in East Asian thought there are two aspects of all things such as light and darkness coexist and are called Yin-Yang (陰陽). The initial concept of Yin-Yang was just a simple expression meant to depict natural phenomena, but it gradually became the central concept in explanations of creation and the changes that undergo all things in the universe. The study of the ordering principle of nature that was known as Myeongli (命理) also examined the interrelation between the sky and the earth and divided the two into Ten Celestial Stems (天干 cheongan) and the Twelve Earth Branches (地支 jiji) based on Yin-Yang theory. This thesis analyzed contents of the relationship between Ten Celestial Stems and the Twelve Earth Branches in terms of the patterns of Mutual Aid (相助 sangjo) and Mutual Contention (相剋 sanggeuk) through a literature review and exploration of their common features and differences. Different categorized phenomena under the pattern of Mutual Aid include Tonggeun (通根 root downward) and Tugan (透干 appearance of the upward). Tonggeun means that signs in the Celestial Stems took root in their counterparts of the Earthly Branches. In the Celestial Stems, there is also Tonggeuncheo (通根處 a place to root downward) which in relation to the Earthly Branches show that the same five phases become Samhap (三合 combined three ways to gain power) and Banghap (方合 gathering in the same season). The methods of seeing Tonggeunryeok (通根力 power of a downward root) are as follows: First, it is seen by the places where Tonggeun takes hold. Ilgan (日干 the Celestial Stem of a birthday) is ordered as month (月 wol) > day (日 il) > hour (時 shi) > year (年 nyeon), and other Celestial Stems appear ordered as month > sitting > close place. Second, it can be seen by the characteristics of Earthly Branches that Tonggeun has taken hold. The Earthly Branches are ordered as Rokwangji (祿旺支 vigorous land) and Jangsaengji (長生支 newborn land) > Yeogi (餘氣 remaining energy) > Myogo (墓庫 storage and burial grounds). Tugan is the concept that the main agent was changed to Tonggeun, which means that the spirit of the Earthly Branches is manifested in the Celestial Stems. And the five phases hidden in the Earthly Branches will be able to play their roles as they are revealed. There are also the phenomena of Gaedu (蓋頭 the heavenly destroying the earthly) and Jeolgak (截脚 the earthly destroying the heavenly) which are concepts that convey that the Heavenly Stems and Earthly Branches can mutually destroy one another. There are different opinions on Gaedu because some adopt viewpoints of just focusing on the Celestial Stems and considering it only in terms the Celestial Stems destroying the Earthly Branches. But, the vast majority of scholars think that the Celestial Stems weakens the role of the roots by destroying the Earthly Branches. Jeolgak, the reverse concept of Gaedu, weakens the spirit of the Celestial Stems as the Earthly Branches destroy them, and this is associated with the strong possibility that one is fated to experience disharmony.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.26 no.1
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• pp.32-39
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• 1981

In order to study the genetic system of the blast resistant varieties, the conidial suspension of mutant races of T-2$^{+t}$, N-2$^{+t}$, C-8$^{+t}$ was inoculated at 4-5 leaf stage by injector for F_2 seedlings from the crosses between seven resistant varieties and four maker lines easily detectable at seedling stage. The results are summarized as follows; 1. The fertility of cross between Semi-dwaf testers and Indica resistant varieties except Carreon was about 74 percents. 2. The segregation modes of resistance varied with varieties and blast races. However, the resistance was expressed as dominance in all cases. Tetep, Tadukan and Carreon showed more complicated segregation for resistance than that of the bred lines. 3. For blast races used, four segregation ratios such as 3:1, 9:7, 13:3 and 37:27 were found in the Tatukan, Tetep, and IR747, and three segregation ratios such as 3:1, 13:3 and 15:1 in the Carreon, and two segregation ratios of 3:1 and 13:3 with Suweon 287, Suweon 288, and Iri342. 4. In the segregation of the resistance to the each races, the ratios of 3:1, 13:3, 15:1 were fitted to T-2$^{+t}$, and the ratios of 3:1, 13:3, 9:7 and 37:27 to N-2$^{+t}$ and C-8$^{+t}$. 5. Suweon 287, Suweon 288 and Iri342 carried one simple dominant gene and inhibitor gene was considered in some cross combinations. Meanwhile Tadukan, Tetep and IR747 seemed to carry one to three resistant genes, and in some cross combinations, the expression of these genes were simple dominant, inhibiting, duplicating and complimentary action. 6. Resistance genes to blast races, T-2$^{+t}$, N-2$^{+t}$ and C-8$^{+t}$ in the Tadukan, Tetep, Carreon, Suweon 287, Suweon 288 and Iri342 were found to be independent with the linkage group of II(lg), VIII(la), XI(bc), and XII(gl).bc), and XII(gl).

• Journal of Service Research and Studies
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• v.13 no.2
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• pp.41-61
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• 2023

The universal form of life in the era of the 4th industrial revolution can probably be summarized as the keyword "non-face-to-face". In particular, in terms of consumption activities, face-to-face contact is gradually changing to a system that minimizes, and offline stores are rapidly changing to non-contact services through kiosks and robots. The social structure is also changing with the passage of time, and most fundamentally, our dietary consumption patterns are changing. In particular, the increase in single-person households and the aging population are having a great impact on changes in the food service industry, which is closely related to dietary life. The HMR (Home Meal Replacement) market has grown significantly as the labor of cooking at home has decreased and the use of substitute foods has increased. As the size of the market has grown, the types of businesses that provide products have also diversified. The development of technology, non-face-to-face culture, and corporate management efficiency are intertwined, and unmanned stores are spreading recently. In this study, service quality attributes of HMR unmanned stores, where competition is gradually intensifying, are classified, and service quality classification using the Kano model and Timko's customer satisfaction coefficient are calculated to provide implications for service management based on customer satisfaction. As a result of the analysis, 'products with short cooking time' and 'variety of products (menu)' were classified as attractive qualities, and 'cleanliness inside/outside of the store' and 'products at reasonable prices' were classified as unified quality. In addition, 'convenience of self-checkout process' was classified as a natural quality, and 'convenience of in-store passage' was classified as an indifferent quality. Furthermore, when the service factor was satisfied within the HMR unmanned store, the factor with the highest satisfaction coefficient was 'product (menu) variety', and the factor with the highest dissatisfaction factor was 'convenience of self-checkout process'. Through the results of this study, it is intended to derive priorities in service quality management of HMR unmanned stores and provide strategic implications for related businesses.

• Journal of Korea Water Resources Association
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• v.56 no.4
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• pp.235-243
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• 2023

Due to the revision of the River Act and the enactment of the Act on the Investigation, Planning, and Management of Water Resources, a regular bed change survey has become mandatory and a system is being prepared such that local governments can manage water resources in a planned manner. Since the topography of a bed cannot be measured directly, it is indirectly measured via contact-type depth measurements such as level survey or using an echo sounder, which features a low spatial resolution and does not allow continuous surveying owing to constraints in data acquisition. Therefore, a depth measurement method using remote sensing-LiDAR or hyperspectral imaging-has recently been developed, which allows a wider area survey than the contact-type method as it acquires hyperspectral images from a lightweight hyperspectral sensor mounted on a frequently operating drone and by applying the optimal bandwidth ratio search algorithm to estimate the depth. In the existing hyperspectral remote sensing technique, specific physical quantities are analyzed after matching the hyperspectral image acquired by the drone's path to the image of a surface unit. Previous studies focus primarily on the application of this technology to measure the bathymetry of sandy rivers, whereas bed materials are rarely evaluated. In this study, the existing hyperspectral image-based water depth estimation technique is applied to rivers with vegetation, whereas spatio-temporal hyperspectral imaging and cross-sectional hyperspectral imaging are performed for two cases in the same area before and after vegetation is removed. The result shows that the water depth estimation in the absence of vegetation is more accurate, and in the presence of vegetation, the water depth is estimated by recognizing the height of vegetation as the bottom. In addition, highly accurate water depth estimation is achieved not only in conventional cross-sectional hyperspectral imaging, but also in spatio-temporal hyperspectral imaging. As such, the possibility of monitoring bed fluctuations (water depth fluctuation) using spatio-temporal hyperspectral imaging is confirmed.