• Journal of the Korean Recycled Construction Resources Institute
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• v.10 no.1
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• pp.92-100
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• 2022

In this paper, to evaluate the effect of SC on the crack self-healing performance and mechanical recovery performance of cement composites, encapsulated intumescent inorganic material-based solid healing materials were prepared. SC was mixed with cement composite materials to evaluate the basic properties, permeability test, and load reload test. SC slightly improved the flow of cement composites, and the compressive strength decreased by about 10 %. Also, the flexural strength decreased by about 30 %. It was found that when SC was mixed with the cement composite material by 5 %, the crack self-healing rate of Plain was improved by about 𝜟10 %. As a result of the load reload test, it was found that the mechanical recovery rate of Plain was improved by about 𝜟20 %. In addition, as a result of analyzing the correlation between the crack self-healing rate and the mechanical recovery rate by the load reload test, it is judged that the healing area of the Plain can be increased due to SC.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.48 no.4
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• pp.321-330
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• 2022

This study attempted to establish an optimal multi-compound simultaneous analysis method that can secure reliable results for 15 - preservatives, 2 - sun screens and 1 - antioxidants of cosmetics using HPLC-PDA. Since the potential of hydrogen (pH) in the mobile phase affects the acid dissociation constant (pKa) of the preservatives, and the peak retention time shift and area change were observed. The peak separation condition was established by adjusting the pH to 0.1% H₃PO₄ addition (mL) when preparing the mobile phase. As a results of method validation, the linearity correlation coefficient (R²) of above 0.999 were obtained, and accuracy 87.9 ~ 101.1%, 0.1 ~ 7.6% precision for two types of cosmetics (cream and shampoo). It was found that the limit of detection (LOD) was 0.1 ~ 0.2 mg/kg and the limit of quantitation (LOQ) was 2.0 ~ 4.0 mg/kg. In addition, it was possible to simultaneously separate p-anisic acid, a natural compound that was difficult to separate in HPLC due to the small difference from methylparaben, a synthetic preservatives. Through this study, it will be effectively used to secure quality control and safety for compound that need restrictions on use cosmetics.

• Korean Journal of Heritage: History & Science
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• v.55 no.2
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• pp.232-249
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• 2022

The purpose of this article is to review the status of designation and preservation, management of national prehistoric sites and to suggest future applications. Prior to the discussion, the overall status of national prehistoric sites was reviewed. Specifically, the current status of designation, designated area, and distribution by region of national prehistoric sites according to the period and nature of the sites were examined in detail. Next, in order to understand the preservation and management of national prehistoric sites, I report the results of field trips to several sites, such as Geomdan-ri in Ulju, Songguk-ri in Buyeo, and Seoktaek-ri in Hongseong, and propose some measures for preservation, maintenance, and management of the remains. Finally, by referring to cases of US national historic sites such as protection, conservation, operation and management system and academic research project of cultural heritage, it is necessary to consider the need for a direction of the utilization that considers both socio-economic aspects as well as education and research on cultural heritage. The active use of cultural heritage can be a measure that leads to the continuous preservation and management of the sites, and ultimately will be a shortcut to increasing the value of national prehistoric sites.

• Journal of Navigation and Port Research
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• v.46 no.4
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• pp.338-343
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• 2022

As the revitalization of the global maritime industry continues, the number of foreign ships navigating the maritime territories of maritime neighboring countries has rapidly increased. However, large-scale marine accidents have occurred, caused by the insufficient establishment of a system for management and operation relative to vessels' safety-condition. To address that, the IMO has granted the right to exercise port state control, especially for foreign vessels, to countries with jurisdiction over maritime territories with strengthening regulations and guidelines. In particular, the Republic of Korea, as a member of the TOKYO MOU, is conducting PSC, but as of 2020, the proportion of foreign ships was three times higher than that of national ships that called in domestic ports. However, the inspection rate was low at 9% which has not met the recommended level by the TOKYO MOU. Thus, this study conducted an IPA analysis as well as content analysis, by collecting the practical opinions and views of PSCO through objective questionnaires and written expert interviews, for improving the efficiency and effectiveness of domestic PSC. As a result, it was derived that the importance and performance related to human factors such as life on board, working environment, and response to safety accidents should be improved in to raise the quality of PSC inspection. Additionally, the work environment and performance of PSC in domestic ports for foreign vessels could be improved, if multifaceted support bases are established, for administrative unification of related tests for PSC, recruitment of PSCO, activation of the defection-reporting system, reorganization of the PSC execution group, etc.

• Korean Journal of Poultry Science
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• v.48 no.4
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• pp.239-253
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• 2021

This study investigates the metabolomic changes in breast and thigh meat from Cobb and Ross 308 chickens regarding the rearing environment. One-day-old Cobb and Ross broilers were raised for 35 days in conventional and animal welfare farms with, amongst others, different floor sizes, stock densities, and ammonia concentrations. One-dimensional ¹H nuclear magnetic resonance, orthogonal partial least squares-discriminant analysis (OPLS-DA), and pathway analyses were performed to analyze the metabolomic properties of broiler meat. For breast meat, only those from the Ross strain could be separated according to the environment in the OPLS-DA plot. Ross breast meat from animal welfare farms showed significantly higher acetate, anserine, creatine, and inosine monophosphate content than those from conventional farms (P<0.05). In contrast, for thigh meat, the Cobb strain was differentiated using OPLS-DA. The contents of five metabolites, such as glucose and lactate, were higher in thigh meat from animal welfare farms; however, nine metabolites, including seven free amino acids, were lower compared to those from conventional farms (P<0.05). Pathway analysis was performed to interpret the biological changes in chicken meat based on environmental factors. The results indicated that the animal welfare environment led to significant changes in four metabolic pathways in Ross breast meat and in 20 metabolic pathways in Cobb thigh meat (P<0.05). In conclusion, the animal welfare environment could influence the metabolomic properties of Ross breast meat and Cobb thigh meat, which may affect the sensory quality of meat.

• Journal of the Korean Society of Radiology
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• v.16 no.2
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• pp.103-113
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• 2022

In this paper, a combined ¹⁸F-FDG(fluorodeoxyglucose) and MNP(magnetic nanoparticles) contrast agent was synthesized using N-(p-maleimidophenyl) isocyanate as the crosslinker for use in simultaneous PET-MRI scans. PET-MRI images were acquired and evaluated before and after injection of the combined contrast imaging agent (¹⁸F-FDG labeled MNP) from a glioma stem cell mouse model. After setting the region of interest (ROI) on each acquired image, the area of the lesion was calculated by segmentation. As a result, the PET image was larger than the MRI. In particular, the simultaneous PET-MRI images showed accurate lesions along with the surrounding soft tissue. The mean and standard deviation values were higher in the MRI images alone than in the PET images or the simultaneous PET-MRI images, regardless of whether the contrast agent was injected. In addition, the simultaneous PET-MRI image values were higher than for the PET images. For PSNR experiments, the original image was PET Image using 18F-FDG, MRI using MNPs, and MRI without contrast medium, and the target image was simultaneous PET-MRI image using 18F-FDG labeled MNPs contrast medium. As a result, all of them appeared significantly, suggesting that the 18F-FDG labeled MNPs contrast medium is useful. Future research is needed to develop an agent that can simultaneously diagnose and treat through SPECT-MRI imaging research that can use various nuclides.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.7
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• pp.1201-1208
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• 2022

In general, to maximize the supply and efficiency of floating offshore wind power generation energy, the motion caused by wave attenuation of the substructure must be reduced. According to previous studies, the motion response was reduced due to the vortex viscosity generated by the damping plate installed in the lower structure among the waves. In this study, a 5 MW semi-submersible OC5 platform and two platforms with attenuation plates were designed, and free decay experiments and numerical calculations were performed to confirm the effect of reducing motion due to vortex viscosity. As a result of the model test, when the heave free decay tests were conducted at drop heights of 30 mm, 40 mm, and 50 mm, compared with the OC5 platform, the platform with two types of damping plates attached had relatively improved motion damping performance. In the model test and numerical calculation results, the damping plate models, KSNU Plate 1 and KSNU Plate 2, were 1.1 times and 1.3 times lower than OC5, respectively, and the KSNU Plate 2 platform showed about two times better damping performance than OC5. This study shows that the area of the damping plate and the vortex viscosity are closely related to the damping rate of the heave motion.

• Journal of Mushroom
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• v.21 no.3
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• pp.190-193
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• 2023

To cultivate pine mushroom (Tricholoma matsutake) artificially, co-cultivation with microorganisms has been introduced. Here, experiments were performed to assess the growth-promoting effect of bacteria on T. matsutake mycelia. Bacteria were isolated from soil samples collected in Yangyang County, Korea. Four of the bacterial isolates (Y22_B06, Y22_B11, Y22_B18, and Y22_B22) exhibited a growth-promoting effect on T. matsutake mycelia (154.67%, 125.91%, 134.06%, and 158.28%, respectively). To analyze the characteristics of the bacteria, especially the antifungal activity, 𝛼-amylase and cellulase activity assays were performed. In comparison with the controls, the isolated bacteria exhibited low 𝛼-amylase and cellulase activity. 16S rRNA gene sequencing was performed to identify the four bacterial isolates. The isolates belonged to the Terrabacteria group and were identified as Microbacterium paraoxydans, Paenibacillus castaneae, Peribacillus frigoritolerans, and P. butanolivorans. These bacterial isolates are expected to have contributed to the growth promotion of T. matsutake mycelia and the artificial cultivation of T. matsutake.

• Journal of Korean Tunnelling and Underground Space Association
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• v.25 no.5
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• pp.387-401
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• 2023

The Earth Pressure Balanced (EPB) Shield Tunnel Boring Machine (TBM) is widely employed for constructing urban underground spaces due to its minimal vibration and low noise levels. The injection of additives offers several advantages, including maintaining shield chamber pressure, reducing shear strength, minimizing cutter wear, and decreasing the permeability of the excavated soil. This technique is known as soil conditioning and involves the application of additives such as foam, polymer, and bentonite slurry. In this study, weathered granite soil commonly encountered at domestic tunnel sites was used as a soil specimen. Foam and polymer were applied as additives to assess the rheological properties of conditioned soils. The workability was evaluated through slump tests, while the rheological properties were assessed through laboratory pressurized vane shear tests conducted under the same conditions. Specially, the polymer was applied under specific conditions with low workability with high slump values, with the aim of evaluating the impact of polymer application. The test results revealed that with an increase in the Foam Injection Ratio (FIR), the slump value also increased, while the torque, peak strength, yield stress, apparent viscosity, and thixotropic area decreased. Conversely, an increase in the Polymer Injection Ratio (PIR) led to results opposite to those of FIR. Additionally, a correlation between the slump value and yield stress was proposed. When comparing conditions with only foam applied to those with both foam and polymer applied, even with similar slump values, the yield stress was found to be lower in the latter conditions.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.21 no.1
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• pp.43-51
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• 1976

Marine deposite soil was studied to evaluate morohological changes of paddy rice under subdrainage control. The content of organic and inorganic mate rial were low at high temperature in the mid-summer. This soil lacked air and accumulated more H$_2$ S. Thus rice root was rotted with high infection of virus and insect and yield was relatively low.