• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.3
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• pp.11-20
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• 2022

The main purpose of this study is to investigate the applicability of the shear wave tomography technology as a non-destructive testing method to evaluate the debonding between the track concrete layer (TCL) and the hydraulically stabilized based course (HSB) of concrete slab tracks for the Korea high-speed railway system. A commercially available multi-channel shear wave measurement device (MIRA) is used to evaluate debonding defects in full-scaled mock-up test specimen that was designed and constructed according to the Rheda 200 system. A part of the mock-up specimen includes two artificial debonding defects with a length and a width of 400mm and thicknesses of 5mm and 10mm, respectively. The tomography images obtained by a MIRA on the surface of the concrete specimens are effective for visualizing the debonding defects in concrete. In this study, a simple image processing method is proposed to suppress the noisy signals reflected from the embedded items (reinforcing steel, precast sleeper, insert, etc.) in TCL, which significantly improves the readability of debonding defects in shear wave tomography images. Results show that debonding maps constructed in this study are effective for visualizing the spatial distribution and the depths of the debondiing defects in the railway concrete slab specimen.

• Journal of the Korean Applied Science and Technology
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• v.38 no.6
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• pp.1466-1475
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• 2021

Compound K (20-O-β-(_D-glucopyranosyl)-20(S)-protopanaxadiol) is an active ingredient of ginsenosides. Compound K has been known to produce from biotransformation by β-glucosidase action of human intestinal microbes after oral admistration of ginseng. We have investigated the cytotoxicity of compound K obtained from bio-converted ginseng extract. As a result, compound K showed no significant cytotoxicity in the concentration of 0.001 to 1 ㎍/mL and inhibited the production of TNF-α, MCP-1, IL-6 and NO in RAW 264.7 cells induced by LPS inflamation. In the same concentration, HaCaT cells induced by inflammation with TNF-α and IFN-γ decreased IL-8 production due to compound K treatment. In the brine shrimp lethality assay, the LC₅₀ of compound K was 0.37 mg/mL indicating some toxicity, but the bioconverted product containing 35% compound K showed relatively low toxicity with an LC₅₀ of 0.87 mg/mL. These results suggest that the compound K enriched extract is a potential functional material for acne relief cosmetic products.

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.6
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• pp.82-92
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• 2022

This study aims to investigate the effect of total electrochemical cell resistance (TECR) on electrochemical impedance (EI) measurements of reinforced concrete (RC) by electrochemical impedance spectroscopy (EIS) using a three-electrode system. A series of experimental study is performed to measure electrochemical behavior of a steel bar embedded in a concrete cube specimen, with a side length of 200 mm, in various experimental conditions. Main variables include concrete dry conditions, coupling resistance between sensing electrodes and concrete surface, and area of the counter electrode. It is demonstrated that EI values remains stable when the compliant voltage of a measuring device is sufficiently great compared to the potential drop caused by TECR of concrete specimens. It is confirmed that the effect of the coupling resistance of TECR is far more influential than other two factors (concrete dry conditions and area of the counter electrode). The results in this study can be used as a fundamental basis for development of a surface-mount sensor for corrosion monitoring of reinforced concrete structures exposed to wet-and-dry cycles under marine environment.

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.6
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• pp.1-13
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• 2022

This study aims to investigate the feasibility of the half-cell potential (HCP) measurements on the concrete surface for evaluation of corrosion rate (or corrosion levels) of reinforcing steel in concrete. A series of experimental study is performed to measure HCP (or corrosion potential, E_corr) and corrosion current density (i_corr) of reinforcing steel in concrete cube specimens, with a side length of 200 mm. Various corrosion levels in a range of 0% to 20% of the test specimens are accelerated by impressing current to the reinforcing steel in concrete immersed in 3.0 % NaCl solution. HCP is measured in accordance with ASTM C876-15, and corrosion current density is determined by using the Stern-Geary equation and measured polarization resistance measured by electrochemical impedance spectroscopy (EIS). As a result, a numerical formula that relates HCP and i_corr in the test specimen is established by a regression analysis of the measured data in this study. It is observed that HCP is linearly correlated with log(i_corr) with a R² greater than 0.87, which is less affected by the experimental variables such as concrete mixture proportion, diameter of reinforcing steel and the amount of applied current in this study. These results exhibit that HCP measurements could be effective for evaluation of corrosion rate (or corrosion levels) of reinforcing steel in concrete in the case of exposed to a certain consistent environment.

• Journal of Korean Society of Disaster and Security
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• v.15 no.3
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• pp.101-113
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• 2022

This study is planned with the aim of developing a systematic construction process based on the scientific and engineering theory of the water-sealing grouting construction applied to the tunnel excavation process during the construction of the downtown underground traffic network, so that the construction quality of the relatively backward domestic tunnel water-sealing grouting construction is improved and continuously maintained no matter who constructs it. The main contents of the improved tunnel water-sealing grouting can be largely examined in the classification of tunnel water-sealing grouting application and the definition of grouting materials, the correlation analysis of groundwater pressure conditions with groundwater inflow, the study of the characteristic factors of bedrock, and the element technologies and injection management techniques required for grouting construction. Looking at the trends in global research, research in the field of theoretical-based science and engineering grouting is actively progressing in Nordic countries (Sweden, Finland, Norway, etc.), Japan, Germany, and the United States. Therefore, in this study, the algorithm is established through theoretical analysis of the elements of tunnel water-sealing grouting construction techniques to provide an integrated solution including a construction process that can effectively construct tunnel water-sealing grouting construction.

• Korean Journal of Plant Resources
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• v.35 no.4
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• pp.515-540
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• 2022

The ultramafic serpentine area, the small size of 3 km², remains in Andong, South Korea. We researched the ecological flora and its structure through the 12 times field investigations from 2013 till 2018. A total of 527 taxa including the previously recorded species-list was analyzed. Among them, 331 taxa were filed up as a real flora of the serpentine area. On the vegetation land-cover map describing a characteristic aspect of species distribution, a matrix of the sparse forest by Pinus densiflora and the grassland patches were the main landscape. The study area was acknowledged as a home for the ethnobotanical species and grassland components, and clearly distinctive from the non-serpentine area. The original habitat was too deteriorated by introducing the non-site soils and exotic plants. Conclusionally a designation of a protected area and the long-term ecological monitoring were requested.

• Journal of Applied Biological Chemistry
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• v.65 no.4
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• pp.313-319
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• 2022

Consumption of high fat diet (HFD) induces obesity by accumulating triglycerides and inflammation in the body. In the present study, we investigated the effects of black onion vinegar (BV) on HFD-induced C57BL/6 obese mice model. The HFD-fed obese mice were administered black onion juice (BJ) and BV, respectively, for 6 weeks. The HFD-fed group increased body and organ weights compared with normal control diet-induced group. However, administration of BV significantly reduced body and organ weights compared with HFD-fed group. The BJ- and BV-administered groups improved the serum lipid profiles such as total cholesterol and triglyceride, compared with HFD-fed group. In addition, BV-administered group significantly improved serum high-density lipoprotein cholesterol and low-density lipoprotein cholesterol. The BV-administered mice had increased the number and size of adipose cells in the liver and adipose tissues. The administrations of BJ and BV significantly down-regulated adipogenesis transcription factors and proinflammatory proteins in the liver compared with HFD-fed group. In particular, BV-administered group showed stronger attenuation of adipogenesis-related proteins than the BJ-administered group. Therefore, this study demonstrated that administration of BV attenuated HFD-induced obesity, in particular down-regulation of adipogenesis, and it could be developed as a functional vinegar for anti-obesity.

• Journal of Marine Life Science
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• v.8 no.1
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• pp.1-7
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• 2023

This study was performed to understand the reproductive ecology of cephalopods, described the microanatomical structure of the male reproductive organs and spermatophore in the common squid, Todarodes pacificus, a major cephalopods in Korea. The common squid was gonochorism and had sexual dimorphism, the color of the reproductive organs reflected on the mantle and the presence of the hectocotylus. Male reproductive organs were composed of testis, primary vas deferens, spermatophoric gland (seminal vesicle), spermatophoric sac (Needham's sac) and secondary vas deferens. The male has specialized reproductive organs such as the spermatophore forming organ, spermatophoric gland. Testis was histologically a seminiferous tubule type. The primary vas deferens was a thin and inverted triangular spring-like form that connected from the rear of the testis to the spermatophoric gland. Inside, it was filled with sperm of basophilic in H-E stain. The spermatophoric gland is an irregular oval connected to the primary vas deferens and spermatophoric sac, and there were a number of tubular glands. The spermatophoric sac is a tubular structure located between spermatophoric gland and secondary vas deferens, and a number of spermatophores have been identified in the lumen. The secondary vas deferens was connected to the posterior of the spermatophoric sac and had a spermatophore inside. The spermatophore was a long, transparent tube about 22 mm long, with a sperm mass inside.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.453-453
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• 2021

도시지역 비점오염원관리, 물순환 회복, 침투 및 증발산량 증가, 열섬현상 저감을 위한 주요한 방안으로 저영향개발(low impact development, LID)과 그린인프라 기법의 적용되고 있다. LID 시설은 소규모 분산형 시설로써 넓은 지역에 많고 다양한 시설들이 적용되어 시설의 개수가 많으며, 수질 및 토양 내 기성제품에 대한 센서들의 가격은 고가로 형성되어 있어 기기의 경제성 및 유지관리 등 적용하는데 제한적이다. 따라서 과거 모니터링 자료를 기반으로 오염물질들과의 상관성 분석을 통하여 계측이 어려운 항목들을 계측가능한 항목들로부터 예측 가능하며, 선정된 항목들에 대한 비용효율적인 센서를 개발하여 실시간 LID 모니터링이 가능한 비용효율적 모니터링을 개발하였다. 공주대학교 천안캠퍼스의 LID 시설들은 2013년에 조성되어 현재까지 시설이 운영되고 있으며, 5년이상의 과거 강우시 모니터링 자료들을 이용하여 오염물질 상관성 분석을 수행가능 하기에 대상지로 선정하였다. 오염물질 상관성 분석은 2013년부터 2017년도에 침투도랑에서 수행된 강우시 모니터링 자료를 활용하여 각 오염물질들의 상관성을 분석을 수행하였다. 침투도랑 내 유입되는 평균 유입수는 TSS 286.1±318.3 mg/L, BOD 22.6±39.5 mg/L, TN 8.96±5.85 mg/L, TP 1.01±1.11 mg/L로 나타났다. 겨울철에 비해 여름철에서의 오염물질의 유입농도가 높은 것으로 분석되었다. 이는 여름철 고온건조로 인한 노면 내 차량의 주행으로 인한 중금속, 폐타이어 등과 장마철 강우 시 유출된 토사로 인하여 유입수의 농도가 높은 것으로 분석되었다. 오염물질 부하량은 TSS와 COD 0.66으로 유의성이 높은 것으로 나왔으며, COD와 TSS, TP, TN 등 유의성이 높은 것으로 분석되었다. Arduino와 Raspberry PI를 활용하여 저비용 센서와 LTE 모뎀통신과 데이터 베이스 연결하여 개발된 프로그램을 통해서 무선으로 LID 시설에 대한 모니터링을 침투화분2와 식생체류지에 조성하였다. 전력공급이 어려운 식생체류지의 경우 태양열(Solar system) 시스템과 보조 전력 배터리를 조성하여 장마철이나 장기적인 악천후로 인한 전력을 생산하지 못할 경우 보조전력배터리에서 전력을 제공하여 지속적인 모니터링이 이루어지도록 설계하였다. 토양함수량, 토양온도와 Conductivity 등 3종류의 센서를 적용하였으며, 프로그램은 현재 2단계를 통한 2차수정을 통하여 프로그램을 구축하였다. 오차, 오작동, 계측값에 대한 검·보정 작업이 필요하다. 또한 대기자료의 구축을 통해 보다 토양과 LID 시설에 대한 영향분석이 필요한 것으로 사료된다.

• The Journal of Korean Philosophical History
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• no.28
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• pp.297-329
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• 2010

This article is a preliminary essay for comparative study on Lao Zi Note of Park Sae Dang who lived Lee Dynasty in 17C and Hayashi La Zan who lived Doku Kawa Bakuhu in 17C. This article have two points at issue. First one is the their challenge that resisted the dogma of their own age. And the other one is their challenge of thaught had the academic background of the Lao Zi Note. They had a their own Lao Zi Note, Park Sae Dang朴世堂 had a New Note of Lao Zi 新註道德經 and Hayashi La Zan 林羅山 had a Selection Note of Lao Zi 老子抄解. However there are some different points between Park Sae Dang and Hayashi La Zan. The Hayashi La Zan's comprehension of Lao Zi followed in Lao Zi Note of Lin Xi Yi 林希逸 who had a point of Confucian comprehension of Lao Zi, so the study of Taoism of Hayashi La Zan excepted Zhuang zi. Hayashi La Zan concentrated on only Confucian comprehension of Lao Zi because Lin Xi Yi's Note of Zhuang Zi had a point of Zen Buddhism. However Park Sae Dang's the study of Taoism has Lao Zi and Zhuang Zi. He understood Lao Zi and Zhuang Zi in a base on Confucian comprehension. He indicated Confucian moral principle 修身治人 for a equal point of between Confucianism and Taoism. And he understood Cheng Xin成心 in Qiwulun in Zhuang Zi is similar to Xing性 of Xing Shan性善 in Meng Zi. Park Sae Dang analyzed not simply Lao Zi but also Zhuang Zi in a base on Confucian comprehension.