• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2016년도 추계학술대회 논문집
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• pp.120-120
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• 2016

Ti-6Al-4V alloy have been used for dental implant because of its excellent biocompatibility, corrosion resistance, and mechanical properties. However, the integration of such implant in bone was not in good condition to achieve improved osseointergraiton. For solving this problem, calcium phosphate (CaP) has been applied as coating materials on Ti alloy implants for hard tissue applications because its chemical similarity to the inorganic component of human bone, capability of conducting bone formation and strong affinity to the surrounding bone tissue. Various metallic elements, such as strontium (Sr), magnesium (Mg), zinc (Zn), sodium (Na), silicon (Si), silver (Ag), and yttrium (Y) are known to play an important role in the bone formation and also affect bone mineral characteristics, such as crystallinity, degradation behavior, and mechanical properties. Especially, Zn is essential for the growth of the human and Zn coating has a major impact on the improvement of corrosion resistance. Plasma electrolytic oxidation (PEO) is a promising technology to produce porous and firmly adherent inorganic Zn containing $TiO_2(Zn-TiO_2)$coatings on Ti surface, and the a mount of Zn introduced in to the coatings can be optimized by altering the electrolyte composition. In this study, corrosion behavior of Ti-6Al-4V alloy after plasma electrolytic oxidation in solutions containing Ca, P and Zn were studied by scanning electron microscopy (SEM), AC impedance, and potentiodynamic polarization test. A series of $Zn-TiO_2$ coatings are produced on Ti dental implant using PEO, with the substitution degree, respectively, at 0, 5, 10 and 20%. The potentiodynamic polarization and AC impedance tests for corrosion behaviors were carried out in 0.9% NaCl solution at similar body temperature using a potentiostat with a scan rate of 1.67mV/s and potential range from -1500mV to +2000mV. Also, AC impedance was performed at frequencies ranging from 10MHz to 100kHz for corrosion resistance.

• 대한조선학회논문집
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• 제48권1호
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• pp.49-55
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• 2011

Sound insulation performance of a unit cabin mock-up is studied, where two identical rooms simulating cruise ship cabin are installed. STL (Sound Transmission Loss) measurement in the mock-up shows that STL of the partition between rooms is degraded by imperfect door ceiling and gap between wall and floor. It is also observed that gap around lighting and electrical outlet slightly affect the STL in high frequency ranges, since lighting and electrical outlet are supported by mineral wool in the back side due to fire-resistance requirement. Even after all possible gaps are sealed, STL of the partition is found to be lower than that measured in the laboratory by 9 dB. Measurement of SBN (Structure-Borne Noise) reveals that flanking transmission of SBN along the steel deck floor can severely deteriorate STL of the partition. Statistical energy analysis (SEA) of the mock-up confirms importance of the floor SBN control, in which increasing damping is essential to ensure high STL.

• 자원환경지질
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• 제46권1호
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• pp.85-91
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• 2013

OECD(2008)는 무대응 비용(inaction cost의 개념을 제시하여 사용가치와 관련된 직접 금전비용, 간접효과를 포함한 총 금전비용, 무형의 가치를 포함한 총 사용비용, 비사용가치를 포함한 총 사회적 복지비용을 제시하였다. 본 연구에서는 이를 환경재의 가치 손상 비용으로 접근하여 지하수, 토양 등의 직 간접사용가치 및 비사용가치의 손상 비용을 분석하고자 하였다. 본 연구에서는 지하수 등 자연환경 가치 분류 및 국내 관련 연구사례를 분석하였다. 그리고 OECD(2008) 무대응 비용을 분석하고 국외 다른 실증 분석 사례 및 유럽 토양기능 저하 분석 모형 등과 연계하였다. 지하수 등 자연환경의 질적, 양적 저하에 대한 무대응 비용의 금전적 측정을 위해서는 인체 피해, 물적 피해를 가시화 할 수 있는 자연환경 변화와 인간, 생태계 영향 간의 물리적 연관성을 추정하는 연구가 핵심적임을 확인하였다.

• 한국축산식품학회지
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• 제41권6호
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• pp.1049-1059
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• 2021

The objective of this study was to evaluate the nutritional content of bullfrog meat from different parts of the animal, including fore-chest, thigh and calf. Bullfrog meat was found to be a rich source of proteins, essential amino acids and minerals, but with a low fat content, compared with other aquatic meat products. There was no significant difference (p>0.05) between thigh and calf in mineral content (K, P, Na, Mg, Ca, Zn, Fe, Cu, and Mn), but the contents of K, P, and Mg were higher in thigh and calf than in the fore-chest (p<0.05). The salt-soluble, water-soluble and insoluble protein bands in sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) electrophoresis, from fore-chest, thigh and calf were similar, with the most abundant bands being 35 kDa (salt-soluble protein), 35-48 kDa (water-soluble protein) and 48 kDa (insoluble protein). The results showed that the insoluble protein content in the fore-chest meat was higher than that in the thigh meat and calf meat, but the salt-soluble protein fraction was the most abundant in thigh meat. These results showed that the nutrients in different parts of bullfrog meat were different.

• Animal Bioscience
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• 제34권4호
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• pp.539-545
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• 2021

Objective: Endometritis is a major disease, that causes infertility in cattle, and is usually categorized as clinical or subclinical endometritis (SCE). The nutritional condition during the dry period is important for recovery after the last stage of the lactation period, and for postpartum production and reproduction. This study aimed to clarify the relationship between nutritional and metabolic characteristics in the dry period, and the risk of postpartum SCE. Methods: Multiparous Holstein dairy cows (n = 25, raised in a tied stall) were used. Endometrial cytological analysis was performed around 30 days post-partum, with 5% to 14% polymorphonuclear (PMN) as a cut-off point to define SCE. Serum levels of glucose, non-esterified fatty acids, β-hydroxybutyric acid (BHBA), blood urea nitrogen, total cholesterol, aspartate aminotransferase, γ-glutamyl transpeptidase, calcium, phosphorus, and magnesium were measured in the cows at the dry period to evaluate energy status, protein metabolism, and mineral metabolism. Results: The incidence of SCE in the cows was 60.0% (n = 15/25) and the mean PMN% in postpartum cows diagnosed as SCE was 8.05%±2.6%. Overall, 17 and 8 samples were collected from the cows in the far-off and close-up periods, respectively. The serum concentration of BHBA in the far-off period and serum glucose concentration in the closeup period were correlated with postpartum PMN% (r = 0.62, p<0.01; r = -0.74, p<0.05, respectively). Serum levels of calcium and magnesium in the dry period were associated with the incidence of postpartum SCE (healthy vs SCE cows, p<0.05). Conclusion: Blood levels of glucose, BHBA, calcium, and magnesium in dry periods could be useful parameters for predicting the risk of postpartum SCE. The present study also suggests that management in the close-up period is essential for promoting recovery from calving fatigue.

• 광물과 암석
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• 제34권1호
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• pp.83-93
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• 2021

2024년 미국항공우주국은 아르테미스 유인 달 탐사를 계획하고 있으며, 2030년대에는 미국을 비롯해 주요 국가들은 인류가 1개월 이상의 장기적인 유인 활동을 추진하기 위한 관련 핵심기술을 개발하고 있는 실정이다. 이러한 계획과 더불어 가장 우선시하여 고려되는 것은 달 현지자원 활용이며, 반드시 필요한 자원은 생명유지를 위한 물과 산소자원이라고 할 수 있다. 이러한 자원은 지구에서 가져가는 것이 아니라 달 표면 현지에서 확보해 활용하는 것이 가장 경제적이며, 달 기지 건설 및 향후 화성으로 진출하기 위한 추진체의 연료로 활용할 수 있는 점에서도 산소자원의 채굴 및 활용방안에 대한 국제적인 연구개발은 활발히 진행되고 있다, 본 논문은 달 표면에서의 산소의 분포 및 산소 추출에 대한 대표적인 방법을 소개하고자 한다.

• International Journal of Industrial Entomology and Biomaterials
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• 제43권2호
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• pp.85-93
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• 2021

Silkworm pupae have been utilized as a food source and have high-quality proteins and fatty acids. However, studies on the nutritional composition of pupae according to their variety, developmental stage, and sex have not been conducted. In this study, the nutritional composition of four Korean silk varieties (Baegokjam, BG; Goldensilk, GS; Juhwangjam, JH; and YeonNokjam, YN) were analyzed according to developmental stage and sex. The main ingredient of the pupa was protein, and the protein levels were higher in females than in males. Fat levels were high in males and increased in YN and GS during the late stage but decreased in BG. Fiber content rapidly increased in the late stages, and the lowest content was observed in BG. The pupae contained all essential amino acids, which were detected at higher ratios in females with a high protein content. Fatty acids had a different predominance depending on the variety. Oleic acid level was high in BG, linoleic acid and linolenic acid levels were high in GS, and palmitic acid and stearic acid levels were high in JH. In the mineral analysis, zinc was dominant in BG, whereas calcium and iron levels were relatively low. Zinc level was low in GS, and calcium and magnesium levels were high in JH. Potassium, sodium, magnesium, and phosphorus levels were low in YN. The silkworm pupae showed differences in components according to their variety, sex, and developmental stage; therefore, selecting a variety suitable for its purpose is necessary.

• 한국수산과학회지
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• 제55권2호
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• pp.91-101
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• 2022

In this study, we analyzed the compositional characteristics of Melosira nummuloides mass-cultured using Jeju lava seawater. M. nummuloides showed the highest growth rate when cultured for 14 days at 17-20℃ and 15,000 lx. Proximate composition of raw-material (RM) and freeze-dried M. nummuloides (FM) showed high ash content (65-72%), while ethanol-extracted M. nummuloides (EM) had low ash and high lipid contents. The predominantly occurring mineral, Si, was 334 g/kg in RM and 269 g/kg in FM, but EM contained only 1.97 g/kg. The ratio of essential amino acids was similar in RM (38.93%) and FM (36.89%) lower in EM (17.83%), but branched chain amino acids required for muscle metabolism was high (63.40%). The polyunsaturated fatty acids of EM (34.74%) was 11% more than that in RM (23.81%), and the ratio of omega-6 to omega-3 fatty acids was 1:3.6. Furthermore, the concentration of total chlorophyll was higher by 5.15 times (62.32 mg/g) and that of fucoxanthin by 7.06 times (11.02 mg/g) in EM than in RM (12.11, 1.56 mg/g, respectively). The mass cultivation and filtration of M. nummuloides using lava seawater has high prospects of commercialization as a competitive bio silica, cosmetic and healthy functional food material.

• Journal of Animal Science and Technology
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• 제63권6호
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• pp.1386-1396
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• 2021

Copper is an essential mineral for pigs, thus it is used as a feed additive in the forms of copper sulfate. Therefore, this study aimed at characterizing the fecal microbiota shifts in pigs as fed by different forms of copper supplementation. 40 growing pigs aged 73 ± 1 days with an average weight of 30.22 ± 1.92kg were randomly divided into 5 groups. The control group (CON) fed with basal diet, while treatment groups were fed a basal diet supplemented with 100 ppm/kg of copper sulfate (CuSO₄), Cu-glycine complex (CuGly), Cu-amino acid complex (CuAA), and Cu-hydroxy(4methylthio)butanoate chelate complex (CuHMB) for 28 days of trial, respectively. The data presented the comparison between inorganic and organic copper supplementation through gut microbiota in growing pigs. Alpha and Beta diversity anaylsis resulted in copper supplementation did shifted gut microbioal community structure. At the phylum level, Firmicutes and Bacteroidetes were the most abundant phyla at all times regardless of treatment. At the genus level, the relative abundances of Prevotella, Lactobacillus, Megasphaera, and SMB53 of the CuGly and CuHMB groups were significantly higher than those of copper sulfate and basal diet groups. Overall, this study may provide the potential role of organic copper replacing inorganic copper, resulting in increased beneficial bacteria in the pig gut.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2023년도 학술발표회
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• pp.247-247
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• 2023

Coastal lagoons play a crucial role in water exchange, water quality, and biodiversity. It is essential to monitor and understand the dynamics of hydrogeochemistry in lagoon water and its groundwater to preserve and sustainably manage the groundwater-dependent ecosystems like coastal lagoons. This study investigated the spatial and temporal hydrogeochemical characteristics of coastal lagoon (Songjiho) and groundwater on the east coast of Korea. The concentrations of major ions, water isotopes, and nutrients (nitrogen and dissolved organic carbon) in lagoon water and groundwater were periodically monitored for one year. The study revealed that major ions and total dissolved solids (TDS) concentration were higher at deeper depths of aquifers and closer to the coastal area. The hydrogeochemical characteristics of coastal lagoon and groundwater chemistry were classified into two types, Ca-Mg-HCO₃ and Na-Cl, based on their spatial location from inland to coastal area. Moreover, the hydrogeochemical characteristics of coastal lagoons and groundwater varied significantly depending on the season. During the wet season, the increased precipitation and evaporation lead to changes in water chemistry. As a result, the total organic carbon (TOC) of coastal lagoons increases during this season, likely due to increased runoff by rainfall whereas the variation of chemical compositions in the lagoon and groundwater were not significant because there is reduced precipitation, resulting in stable water levels and during the dry season. The study emphasizes the impact of spatial distribution and seasonal changes in precipitation, evaporation, and river discharge on the hydrogeochemical characteristics of the coastal aquifer and lagoon system. Understanding these impacts is crucial for managing and protecting coastal lagoons and groundwater resources.