• Journal of Animal Science and Technology
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• v.63 no.4
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• pp.766-777
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• 2021

Bezafibrate, a fibrate drug used as a lipid-lowering agent to treat hyperlipidemia, is a pan-agonist of peroxisome proliferator-activated receptor alpha. It can enhance mitochondrial fatty acid oxidation, oxidative phosphorylation, and mitochondrial biogenesis. After ovulation, oocytes may get arrested at the metaphase II (MII) stage until fertilization beyond optimal timing, which is termed as post-ovulatory aging. Post-ovulatory aging is a disease that degrades DNA, mitochondria, and oxidative system, and has a negative impact on embryo development and quality; however, the impact of bezafibrate during post-ovulatory aging has not been fully defined. In the present study, we assessed the ability of bezafibrate to prevent the progression of aging in in vitro conditions as well as the underlying mechanisms in pigs. An appropriate concentration of this drug (50 µM) was added, and then oxidative stress, reactive oxygen species downstream, mitochondrial biogenesis, and mitochondrial function were analyzed via immunofluorescence staining and real-time polymerase chain reaction. Bezafibrate significantly alleviated reactive oxygen species and ameliorated glutathione production simultaneously in oocytes and embryos. Moreover, it diminished H2A.X and attenuated CASPASE 3 expression produced by oxidative stress in oocytes and embryos. Furthermore, bezafibrate remarkably improved the mitochondrial function and blastocyst quality as well as markedly reduced the mitochondria/TOM20 ratio and mtDNA copy number. The elevated PARKIN level indicated that mitophagy was induced by bezafibrate treatment after post-ovulatory aging. Collectively, these results suggest that bezafibrate beneficially affects against porcine post-ovulatory oocyte aging in porcine by its antioxidant property and mitochondrial protection.

• Journal of the Korea Convergence Society
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• v.12 no.2
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• pp.271-277
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• 2021

Companies are actively engaged in various innovation activities and intellectual property rights activities such as patents in order to survive in a fiercely competitive global environment. The purpose of this study is to understand the factors that influence corporate patent-related activities on business results. For this reason, we conducted a questionnaire survey of patent practitioners and R & D personnel of Chinese companies, and analyzed the causal relationship using PLS analysis tools. As a result of the analysis, it was found that compensation and obstacle factors have a significant effect on information sharing (collaboration)... It was found that information sharing (collaboration) has a significant impact on technology complementation (improvement) and corporate image. It was also found that technical complementation (improvement) and corporate image have an impact on management results. The results of this study will be able to find and strategically utilize the factors that promote and encourage companies to develop their patent activities.

• Journal of the Korean Society of Visualization
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• v.19 no.3
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• pp.15-21
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• 2021

In this study, we investigated the dynamics of a droplet impacting rough hydrophobic surfaces through high-speed imaging. Micrometer-sized structures with grooves and pillars were fabricated on smooth Polydimethylsiloxane (PDMS) surfaces by laser ablation. We used Newtonian and non-Newtonian liquid droplets to study the drop impact dynamics. De-ionized water and aqueous glycerin solutions were used for the Newtonian liquid droplet. The solutions of xanthan gum in water were prepared to provide elastic property to the Newtonian droplet. We found that the orientation of the surface structures affected the maximal spreading diameter of the droplet due to the degree of slippage. During the droplet retraction, the dynamic receding contact angles were measured to be around 90° or less. It resulted in the formation of the micro-capillary bridges between the receding droplet and the surface structures. Then, the rupture of the capillary bridge led to the formation of micrometer-sized droplets on top of the surface structures. The size of the microdroplets was found to increase with increasing the impacting velocity and viscosity of the Newtonian liquid droplets. However, the size of the isolated microdroplets decreased with enhancing the elasticity of the droplets, and the size of the non-Newtonian microdroplets was not affected by the impacting velocity.

• Nuclear Engineering and Technology
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• v.54 no.11
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• pp.4072-4083
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• 2022

Ultrasonic impact treatment (UIT) is carried out on the Ni-based alloy stainless steel pipe gas tungsten arc welding (GTAW) girth weld, the differences of microstructure, microhardness and shear strength distribution of the joint before and after ultrasonic shock are studied by microhardness test and shear punch test. The results show that after UIT, the plastic deformation layer is formed on the outside surface of the Ni-based alloy overlayer, single-phase austenite and γ type precipitates are formed in the overlayer, and a large number of columnar crystals are formed on the bottom side of the overlayer. The average microhardness of the overlayer increased from 221 H V to 254 H V by 14.9%, the shear strength increased from 696 MPa to 882 MPa with an increase of 26.7% and the transverse average residual stress decreased from 102.71 MPa (tensile stress) to -18.33 MPa (compressive stress), the longitudinal average residual stress decreased from 114.87 MPa (tensile stress) to -84.64 MPa (compressive stress). The fracture surface has been appeared obvious shear lip marks and a few dimples. The element migrates at the fusion boundary between the Ni-based alloy overlayer and the austenitic stainless steel joint, which is leaded to form a local martensite zone and appear hot cracks. The welded joint is cooled by FA solidification mode, which is forming a large number of late and skeleton ferrite phase with an average microhardness of 190 H V and no obvious change in shear strength. The base metal is all austenitic phase with an average microhardness of 206 H V and shear strength of 696 MPa.

• Korean Journal of Materials Research
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• v.34 no.1
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• pp.44-54
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• 2024

High-Manganese (Mn) austenitic steel, with over 24 wt% Mn content, offers outstanding mechanical properties in cryogenic settings, making it a potential replacement for existing cryogenic materials. This high manganese steel exhibits high strength, ductility, and wear resistance, making it promising for applications like LNG tanks, flanges, and valves. To operate in cryogenic environments, hot forging and heat treatment processes are vital, especially in flange production. The cooling rate during high-temperature cooling after hot forging plays a critical role in influencing the microstructure and mechanical properties of high manganese steel. The rate at which cooling occurs during this process influences the size of the grains and the distribution of manganese and consequently has an impact on mechanical properties. This study assessed the microstructure and mechanical properties based on different cooling rates during the hot forging of High-Mn steel flanges. Comparing air and water cooling after hot forging, followed by heat treatment, revealed notable differences in grain size. These differences directly impacted mechanical properties such as tensile strength, hardness, and Charpy impact property. Understanding these effects is crucial for optimizing the performance and reliability of High-Mn steel in cryogenic applications.

• Composites Research
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• v.37 no.3
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• pp.186-189
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• 2024

This study compared and evaluated the mechanical properties of carbon fiber reinforced thermoplastic polymer (CFRTP) mixed with nanofillers. After mixing various nanofillers such as Multi-wall carbon nanotube (MWCNT), Silicon oxide, Core shell rubber, and Aramid nanofiber with Polyamide 6 (PA6) resin, this is used as a matrix to create a carbon fiber reinforced composite material (CFRP) was manufactured and its physical properties were measured. Depending on the type and mixing ratio of nanofiller, tensile strength, inter-laminar shear strength (ILSS), and Izod impact strength were measured. In terms of tensile strength and impact strength, the highest values were obtained when mixing core shell rubber, however the ILSS was optimal when mixing less than 1 wt.% of silicon oxide.

• Journal of the Korean Association of Geographic Information Studies
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• v.19 no.4
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• pp.36-51
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• 2016

This study assessed urban flood risk using a Bayesian probability statistical method and GIS incorporating a climate change scenario. Risk is assessed based on a combination of hazard probability and its consequences, the degree of impact. Flood probability was calculated on the basis of a Bayesian model and future flood occurrence likelihoods were estimated using climate change scenario data. The flood impacts include human and property damage. Focusing on Seocho-gu, Seoul, the findings are as follows. Current flood probability is high in areas near rivers, as well as low lying and impervious areas, such as Seocho-dong and Banpo-dong. Flood risk areas are predicted to increase by a multiple of 1.3 from 2030 to 2050. Risk assessment results generally show that human risk is relatively high in high-rise residential zones, whereas property risk is high in commercial zones. The magnitude of property damage risk for 2050 increased by 6.6% compared to 2030. The proposed flood risk assessment method provides detailed spatial results that will contribute to decision making for disaster mitigation.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.18 no.4
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• pp.283-293
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• 2006

The purpose of this study is to quantitatively estimate the erosional properties for cohesive sediments on Keum Estuary. Then the spatial variation was evaluated, through analyzing and comparing the seasonal variation of the erosional properties in Keum Estuary with that of the erosional properties in the other sites. As erosional properties of cohesive sediments are also influenced largely by basic physico-chemical property of cohesive sediments themselves, the impact that the basic physico-chemical property has on the erosional properties is analyzed in this study. Erosional tests are performed under the condition of uniform beds. Total 8 times of tests using an annular flume are also conducted in a location, low times respectively by seasons: the fall, winter. Experimental results of erosional tests show that the critical shear stress for erosion varies in the range of $0.12{\sim}0.36N/m^2$ and the coefficient of erosion rate varies in the range of $120.91{\sim}6.72mg/cm^2{\cdot}hr$, over the corresponding bulk-density range $1.15{\sim}1.34g/cm^3$. Although the calculated parameters of erosional properties are remarkably different in quantity compared with those of other cohesive sediments(lake Okeechobee) and Kaolinite, their seasonal variabilities within Keum Estuary appear to be insignificant.

• Geomechanics and Engineering
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• v.21 no.1
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• pp.63-71
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• 2020

Strength anisotropy is a typical feature of thin-bedded rock masses and their strength will be degraded subjected to water immersion effect. Such effect is crucial for the operation of hydropower plant because the impoundment lifts the water level of upstream reservoir and causes the rock mass of nearby slopes saturated. So far, researches regarding mechanical property of natural thin-bedded rock masses and their strength variation under water immersion based on field test method are rarely reported. This paper focuses on a thin-bedded stratified rock mass and carries out field test to investigate the mechanical property and strength variation characteristics. The field test is highlighted by samples which have a large shear dimension of 0.5 m*0.5 m, representing a more realistic in-situ situation than small size specimen. The test results confirm the anisotropic nature of the concerned rock mass, whose shear strength of host rocks is significantly larger than that of bedding planes. Further, the comparison of shear strength parameters of the thin-bedded rock mass under natural and saturated conditions show that for both host rocks and bedding planes, the decreasing extent of cohesion values are larger than friction values. The quantitative results are then adopted to analyze the influence of reservoir impoundment of a hydropower plant on the surrounding rock mass stability of diversion tunnels which are located in the nearby slope bank. It is evaluated that after reservoir impoundment, the strength degradation induced incremental deformations of surrounding rock mass of diversion tunnels are small and the stresses in lining structure are acceptable. It is therefore concluded that the influences of impoundment are small and the stability of diversion tunnels can be still achieved. The finings regarding field test method and its results, as well as the numerical evaluation conclusions are hoped to provide references for rock projects with similar concerns.

• Smart Media Journal
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• v.11 no.7
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• pp.28-38
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• 2022

The term 'fourth industrial revolution' was mentioned at the World Economic Forum (WEF) in 2016 and has become a term representing a new industrial era based on information and communication technology (ICT). In the environment of the 4th industrial revolution, ESG management activities are becoming a very important factor in business activities. With the emergence of a new paradigm of organizational operation in the post Covid19 era, the demands for ESG (Environment, Social, Governance) investment related to the environment, social responsibility are increasing. This study examines the role that can support ESG management by utilizing the expertise of appraisers. Real estate is one of the fields of high public interest, and since most ESGs have been conducted centered on the role of private companies, the role of the expert group or the role of public corporations and public institutions is relatively insufficient. If a company or general company engaged in the real estate investment business establishes the role of the Korea Appraisers Association to revitalize ESG management using appraisers, such as ESG appraisers, when investing in real estate, it is believed that it will be possible to promote efficient and sound development of the real estate industry. It was judged that a study on a group of experts was also necessary. In addition, even if the impact of Covid-19 is excluded, it is necessary to gradually introduce an appraisal using non-face-to-face or various advanced technologies (the 4th industry). This study differs from previous studies in that it focused on the role of ESG by the Korea Association of Property Appraisers while research on the role of ESG in public institutions or expert groups is being actively conducted in recent years.