• Journal of Korean Society of Disaster and Security
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• v.16 no.2
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• pp.85-98
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• 2023

Flood is one of the most frequent natural disasters worldwide. In Korea, the probability of urban flooding is greatly increasing due to complex factors such as global warming, an increase in impervious areas, and limitations in expanding water supply facilities in existing urban areas. However, large-scale civil engineering works to prevent urban inundation are socially and economically difficult to obtain national consent. Recently the importance of resilience, which is the ability to return to the original state after a disaster through rapid recovery while preparing for natural disasters to a level that the local community can afford socially and economically, is increasing. Accordingly, various studies on urban resilience have been conducted, but the resilience measurement method related to the lifeline that provides essential services of the city is insufficient. However, among lifelines, road networks are important facilities for the transportation of recovery resources and rapid recovery in the event of a natural disaster, so road networks are a major factor that must be considered when measuring the degree of recovery of a city in the field of natural disasters. Therefore, this study proposes a recovery evaluation method considering the characteristics of resilience and road networks in the urban flooding field and analyzes the effect of road networks on urban resilience.

• Korean Journal of Heritage: History & Science
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• v.56 no.4
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• pp.160-189
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• 2023

The Cheonjeon-ri petroglyph is inscribed with shale formation belonging to the Daegu Formation of the Gyeongsang Supergroup in the Cretaceous of the Mesozoic Era. This rock undergoes thermal alteration to become hornfels, and has a high hardness and dense texture. Rock-forming minerals have almost the same composition as quartz, alkali felspar, plagioclase, calcite, mica, chlorite and opaque minerals, but calcite is rarely detected in the weathered zone. The petroglyph forms a weathered zone with a certain depth, and there is a difference in mineral and chemical composition between weathered and unweathered zones, respectively. The CaO contents of the weathered zone were reduced by more than 90% compared to that of the unweathered zone, because calcite reacted with water and dissolved. As a result of calculating the surface weathering depth for the petroglyph with the transmission characteristics of X-rays, depth of the parts in falling off and exfoliation showed a depth of about 0.5 to 1 mm, but the weathering depth in most areas was calculated to be about 3 to 4 mm. This can be proved by the contents and changes of Ca and Sr. The surface discolorations of the petroglyph are distributed with different color density, and the yellowish brown discoloration is alternated with a thin biofilm layer, showing a coverage of 79.6%. Therefore, periodic preservation managements and preventive conservation monitoring that can effectively control the physicochemical and biological damages of the Cheonjeonri petroglyph will be necessary.

• Journal of Soil and Groundwater Environment
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• v.28 no.6
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• pp.71-89
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• 2023

A groundwater potential map (GPM) was built for the Nakdonggang River Basin based on ten variables, including hydrogeologic unit, fault-line density, depth to groundwater, distance to surface water, lineament density, slope, stream drainage density, soil drainage, land cover, and annual rainfall. To integrate the thematic layers for GPM, the criteria were first weighted using the Analytic Hierarchical Process (AHP) and then overlaid using the Technique for Ordering Preferences by Similarity to Ideal Solution (TOPSIS) model. Finally, the groundwater potential was categorized into five classes (very high (VH), high (H), moderate (M), low (L), very low (VL)) and verified by examining the specific capacity of individual wells on each class. The wells in the area categorized as VH showed the highest median specific capacity (5.2 m³/day/m), while the wells with specific capacity < 1.39 m³/day/m were distributed in the areas categorized as L or VL. The accuracy of GPM generated in the work looked acceptable, although the specific capacity data were not enough to verify GPM in the studied large watershed. To create GPMs for the determination of high-yield well locations, the resolution and reliability of thematic maps should be improved. Criterion values for groundwater potential should be established when machine learning or statistical models are used in the GPM evaluation process.

• The Journal of Engineering Geology
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• v.33 no.4
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• pp.627-638
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• 2023

This study aimed to evaluate the spatial variability of downstream river flow resulting from the operation of the Gimcheon Buhang Dam in the Gamcheon watershed. The dam's effects on flood reduction during the flood season and on increasing streamflow during the dry season-two main functions of multipurpose dams-were quantitatively analyzed. Streamflow data from 2013 to 2021 for the study waterhsed were simulated on a daily basis using SWAT-K (Soil and Water Assessment Tool - Korea) model. Comparison of the simulated and observed values found goodness of fit values of 0.75 or higher for both the coefficient of determination and the Nash-Sutcliffe model efficiency coefficient. The spatial analysis of the dam's effect on flood reduction focused on the annual maximum flood: rates of flood reduction at the four stations ranged from 8.5% to 25.0%. The evaluation of streamflow increase during times of low flow focused on flow duration curves: in particular, compared to the case without an upstream dam, the average low flow at the four sites increased from 33% to 198%.

• Korean Journal of Poultry Science
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• v.50 no.4
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• pp.251-260
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• 2023

This study was conducted to investigate the effect of propolis extract on chicken patty. the meat quality characteristics and storage properties of chicken patties without propolis extract were compared to those with 0.1%, 0.2%, and 0.4% propolis ethanol extract. The addition of propolis extract resulted in increased fat and ash content in the chicken patties. There were no differences in pH, water holding capacity, cooking loss, and texture profile analysis, indicating that the propolis extract did not negatively affect emulsification stability. However, sensory evaluation showed that the higher the concentration of propolis extract added, the lower the total preference of the chicken patties. Over a storage period, patties treated with propolis extract exhibited a lower total microbial count, and volatile basic nitrogen (VBN) content compared to those without propolis extract. Therefore, the addition of propolis to chicken patties does not reduce emulsion stability but improves storage properties. However, the unique flavor of propolis decreases the preference for chicken patties, so the amount must be considered when using it.

• The Journal of the Convergence on Culture Technology
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• v.9 no.6
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• pp.867-873
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• 2023

In this study, for the purpose of standardized quality control of a cold medicine, we simultaneous analyzed four main chemical components of a cold medicine: acetaminophen, caffeine, methyl paraben, and propyl paraben. The sample was subjected to quantitative analysis using high performance liquid chromatography (HPLC), after pretreatment of four components. The experiment was carried out by using Isocratic elution at wavelength of 270nm. Acetonitrile and water (H₂O) were used as a mobile phase at a flow rate of 1.0mL/min in a commercial C18 reversed-phase column. A volume of 10uL cold medicine were injected into the column with column oven temperature at 35℃. As a result of the experiment, the values of Resolution were 4.983, 1.596, 5.519, and 1.678 respectively-well over Rs >1.5, which indicates that the separation of four components were efficient. In addition, value of symmetry factor of the components was 1.056, 1.069, 1.032, and 1.133 respectively, to show its symmetrical stability. The calibration curve of all four components exhibits good linearity with R² >0.9995 to 0.9999. Furthermore, the limit of detection(LOD) were between 0.0118 to 1.5973 mg/mL, while the limit of quantification (LOQ) were between 0.0353 to 4.7919 ㎍/mL with the recovery rate of 79.6% ~ 120.5%. The results of this study showed an efficient quality evaluation of a simultaneous analysis method for cold medicine components.

• Journal of the Korean Geotechnical Society
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• v.39 no.12
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• pp.61-73
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• 2023

Suction buckets are feasible options for offshore foundations to support subsea structures in deep water, enabling suction-induced installation by pumps. Recently, hybrid suction bucket foundations that combine single or multiple suction buckets with a mat foundation have been considered. The foundations effectively increase the load capacity while reducing construction costs. However, there is still insufficient experimental validation of hybrid suction bucket foundations regarding their bearing capacity. Furthermore, research on the horizontal load capacity under low vertical and moment loads is inadequate. In this study, we investigate the feasibility of using a hybrid suction bucket foundation for subsea installations in clay. We considered two types of hybrid suction bucket foundations: a circular mat with a single suction bucket and a square mat with multiple buckets. Centrifuge tests were performed to understand the hybrid suction bucket foundation characteristics under horizontal loads and their corresponding bearing capacity. Particularly, we verified the effect of the mat foundation and bucket embedment depth on the horizontal bearing mechanism and capacities. Results confirmed that the hybrid suction bucket foundation outperforms the single suction bucket.

• Journal of the Korea Institute of Building Construction
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• v.23 no.6
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• pp.703-714
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• 2023

This research conducts a series of tests to investigate the setting retarding properties and strength development in cement pastes incorporating various types and dosages of sugar-based super retarding agents. Six such agents, including Sucrose, Sugar powder, Saccharin, Aspartame, Stevioside, and Mogroside, commercially available, were selected for evaluation. The study also examines the micro-structural properties of these cement pastes. The test mixtures were prepared using a 27.5% water-to-cement ratio and ordinary Portland cement. Micro-structural analyses were conducted using Scanning Electron Microscopy(SEM), X-Ray Diffraction(XRD), and Energy Dispersive Spectroscopy(EDS). The findings reveal that the incorporation of sucrose, sugar powder, and stevioside significantly retards the setting time. Particularly, adding 0.1% sucrose extended the setting time by approximately two-fold compared to the control(Plain) mixture. Most mixtures, barring those with sugar powder and stevioside, exhibited compressive strength comparable to the Plain mixture. Notably, with 0.2% sucrose, strength measurements were not feasible at 1 day, but at 3 days, the strength gains aligned with the Plain mixture. XRD, SEM, and EDS analyses confirmed the hydration delay(set retarding) of C3S due to sucrose, with further quantitative corroboration provided by EDS. SEM was used to verify the presence or absence of hydration products. The study concludes that sucrose, as a sugar-based retarder, offers effective set retarding capabilities and compressive strength development in concrete.

• Journal of Environmental Science International
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• v.33 no.4
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• pp.257-268
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• 2024

This study investigated the growth characteristics of Euonymus japonicus, Hedera helix, and Peperomia puteolata treated with different calcium chloride (CaCl₂) concentrations to evaluate salt tolerance limits in hydroculture cultivation. Six concentrations of CaCl₂ (0, 1, 2, 5, 10, and 15 g·L^-1 referred to as Cont., C1, C2, C5, C10, and C15) were applied to solution - grown plant species. The survival rate, growth index, plant height, plant width, leaf width, leaf length, number of leaves, and relative chlorophyll contents were measured at monthly intervals. Euonymus japonicus, Hedera helix, and Peperomia puteolata survived up to C2, C5, and C10 at each CaCl₂ concentration. The Euonymus japonicus was higher in the C1 treatment than in the Cont. for most growth characteristics. Hedera helix had the highest leaf width, leaf length, and number of leaves in the Cont., a significant difference was observed compared with the C1 treatment. The chlorophyll content did not differ significantly between the C5 and Cont. treatments. The leaf width and length of Peperomia puteolata were greater in the C2 and C1 treatments than in the Cont., whereas the number of leaves and chlorophyll content were the highest in C5. Dry weight analysis revealed that Euonymus japonicus, Hedera helix, and Peperomia puteolata were the lowest in the Cont. treatments. Euonymus japonicus was 74% in C15, and Hedera helix, and Peperomia puteolata were analyzed at approximately 37%- 50% and 9%-14%, respectively, regardless of the concentration in the CaCl₂ treatment groups. In indoor hydroponic cultivation, the salt tolerance limit concentrations of Euonymus japonicus, Hedera helix, and Peperomia puteolata are 2, 5, and 10 g·L^-1, respectively, indicating that hydroculture management techniques should be applied at higher concentrations.

• Journal of Life Science
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• v.34 no.4
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• pp.215-226
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• 2024

Aralia continentalis is widely distributed in Far East Asian countries such as Korea, China, and Japan. A. continentalis has traditionally been used as an herbal remedy for various conditions, including analgesia, headache, inflammation, lameness, lumbago, rheumatism, and dental diseases in Korea. Previously, epi-continentalic acid, continentalic acid, and kaurenoic acid as major active biological compounds belonging to the diterpenoid class were identified. To synthesize diterpenoid derivatives with enhanced bioavailability, Fusarium fujikuroi was employed to biotransform diterpenoids due to its known antibacterial activity. This yielded two derivatives of kaurenoic acid, namely 16α-hydroxyent-kauran-2-on-19-oic acid and 2β, 16α-dihydroxy-ent-kauran-19-oic acid, with their chemical structures elucidated via NMR analysis. These derivatives exhibited increased polarity compared to kaur- enoic acid, as evidenced by their retention time on preparative HPLC using the ODS-A column and structural modifications. Evaluation of their antidiabetic activity targeting PTP1B, a negative regulator of the insulin signaling pathway, revealed inhibitory activities of 30.8% and 27.6%, respectively, at a concentration of 4 ㎍/ml. Additionally, both derivatives demonstrated low cytotoxicity, with an IC50 value 18 times higher than kaurenoic acid. Therefore, the augmented water solubility and reduced toxicity of 16α-hydroxy-ent-kauran-2-on-19-oic acid and 2β, 16α-dihydroxy-ent-kauran-19-oic acid, resulting from biotransformation by F. fujikuroi, render them promising candidates for industrial applications.