제주도 지하수 질산염 농도의 시·공간적 변화 특성: 장기(1993-2015) 모니터링 자료의 평가

김호림(Ho-Rim Kim),오준섭(Junseop Oh),도현권(Hyun-Kwon Do),이경진(Kyung-Jin Lee),현익현(Ik-Hyun Hyun),오상실(Sang-Sil Oh),감상규(Sang-Kyu Kam),윤성택(Seong-Taek Yun) 대한자원환경지질학회 2018 자원환경지질 Vol.51 No.1

1993년부터 2015년까지 관측된 제주도 지하수 장기모니터링 관측정(N = 4,835)에서 수집된 지하수 수질자료(N = 21,568)를 기반으로 질산성질소의 시공간적 변동 특성을 평가하였다. 제주도 지하수의 질산성질소 농도의 중앙값은 2.5 mg/L로서 다른 국가나 대륙의 조사 결과에 비해 다소 높거나 유사한 것으로 나타났다. 또한 지하수 용도, 행정구역 및 고도 별로 유의한 차이를 보였다. 특히, 산간 지역에 비해 저지대 해안가에 위치한 농업 및 주거지역에서 농도가 높음을 확인하였다. Mann-Kendall 및 Sen’s slope 분석을 활용한 질산성질소 농도의 추세 분석 결과, 하류 저지 대에 비해 중산간지역에서의 질산성질소 농도 증가 경향이 뚜렷하였다. 제주도 내 토지 피복의 시계열 변화 특성과 결부 지어 보면, 중산간지역의 오염 증가 추세는 농업지역의 확장 등 인위적 활동 증가에 기인한 결과로 판단된다. 반면,기지정된 지하수자원특별관리구역에서는 전반적으로 질산성질소 농도의 감소 경향이 나타났는데, 이는 지하수 관리 측면에서 수질관리를 위한 적극적인 정책이 유효함을 시사한다. 본 연구에서는 제주도 지하수의 질산성질소 오염관리를 위한 적정 방안을 제안한다. The spatio-temporal variations of nitrate concentrations in groundwater of Jeju Island were evaluated by an analysis of time series groundwater quality data (N = 21,568) that were collected from regional groundwater monitoring (number of wells = 4,835) for up to 20 years between 1993 and 2015. The median concentration of NO 3 -N is 2.5 mg/L, which is slightly higher than those reported from regional surveys in other countries. Nitrate concentrations of groundwater in wells tend to significantly vary according to different water usage (of the well), administrative districts, and topographic elevations: nitrate level is higher in low-lying agricultural and residential areas than those in high mountainous areas. The Mann-Kendall trend test and Sen’s slope analysis show that nitrate concentration in mid-mountainous areas tends to increase, possibly due to the expansion of agricultural areas toward highland. On the other hand, nitrate concentrations in the Specially Designated Groundwater Quality Protection Zones show the temporally decreasing trend, which implies the efficiency of groundwater management actions in Jeju. Proper measures for sustainable groundwater quality management are suggested in this study.

Conceptual Study for Tissue-Regenerative Biodegradable Magnesium Implant Integrated with Nitric Oxide-Releasing Nanofi bers

Jin‑Kyung Jeon,Hyunseon Seo,Jimin Park,Soo Ji Son,Yeong Rim Kim,Eun Shil Kim,Jong Woong Park,Woong‑Gyo Jung,Hojeong Jeon,Yu‑Chan Kim,Hyun‑Kwang Seok,Jae Ho Shin,Myoung‑Ryul Ok 대한금속·재료학회 2019 METALS AND MATERIALS International Vol.25 No.4

The excessive initial corrosion rate of Mg is a critical limitation in the clinical application of biodegradable Mg implantsbecause the device loses its fi xation strength before the fractured bone heals. This study suggests a new approach to overcomethis hurdle by accelerating tissue regeneration instead of delaying the implant biodegradation. As angiogenesis is anessential process in early bone regeneration, a Mg implant coated with electrospun nanofi bers containing nitric oxide (NO),which physiologically promotes angiogenesis, is designed. The integrated device enables adjustable amounts of NO to bestored on the NO donor-conjugated nanofi ber coating, stably delivered, and released to the fractured bone tissue near theimplanted sites. An in vitro corrosion test reveals no adverse eff ect of the released NO on the corrosion behavior of the Mgimplant. Simultaneously, the optimal concentration level of NO released from the implant signifi cantly enhances tube networkformation of human umbilical vein endothelial cells without any cytotoxicity problem. This indicates that angiogenesis canbe accelerated by combining NO-releasing nanofi bers with a Mg implant. With its proven feasibility, the proposed approachcould be a novel solution for the initial stability problem of biodegradable Mg implants, leading to successful bone fi xation.

Effects of Pilger Rolling and Heat Treatment on Microstructure and Corrosion Resistance of Ag-electroplated 304 Stainless Steel Tubes

Hyun Park,Woo‑Jin Lee,Jae‑Han Son,Han‑Kyun Shin,Sung‑Kyu Hong,Hyo‑Jong Lee 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.8

We introduce a cost-effective method that combines electroplating with metal cold working processes to manufacture compositetubes with robust corrosion resistance. First, a 3-step electroplating process was developed to form an adhesive anduniform Ag coating on the outer wall of a 304 stainless steel tube. The process consisted of a Ni-strike step for removing thepassivation layer of the initial 304 tube, Cu deposition for smoothing the surface by adding a buffer layer, and Ag deposition. To reinforce the interfacial adhesion between the electroplated layers and the 304 tube and increase the area of the Ag coating,a pilger rolling or pilger rolling + heat-treatment process was performed after the Ag electroplating process. Scanningelectron microscopy of the composite tubes after each process indicated that the as-deposited Ag coating changed fromhaving a rough to smooth surface after only pilger rolling and with additional heat treatment. Electron backscatter diffractionanalysis of the microstructures and textures of the tubes revealed that dynamic recrystallization occurred extensively duringpilger rolling, resulting in the formation of a relatively defect-free grain structure without heat treatment. Furthermore,electrochemical polarization curves determined that the Ag-coated composite tubes are superior to the uncoated 304 tubein terms of corrosion resistance under Cl−atmosphere, owing to the formation of a AgCl passivation layer during testing. Surface analysis of the composite tubes suggests that the properties of the AgCl passivation layer are related to the grainsize of the Ag coating and the density of plastic-deformation-induced defects.

Bretton Woods System and Japan's International Capital Movement Policy in the Period of High Economic Growth

Hyun,Jin-Duk 고려대학교 아세아문제연구소 2002 亞細亞硏究 Vol.45 No.1

Application of Artificial Insemination Technology for Dairy Breeding in Mongolia

Hyun‐Tae Jo,Jong‐In Jin,Seong‐Su Kim,Byung‐Hyun Choi,Tumor Baldan,Jung‐Gyu Lee,Yun‐Shik Kim,Sam‐Churl Kim,Il‐Keun Kong 한국동물생명공학회(구 한국동물번식학회) 2011 발생공학 국제심포지엄 및 학술대회 Vol.2011 No.1

This study was focused on improvement of milk production in Mongolia dairy industry by artificial insemination (AI) technology, of which was supported from ODA project of KOICA in Republic of Korea. The study was started from January 2009 to present and 3rd years in this year. So, all data, especially synchronization and pregnancy of dairy cows (Holstein) will be summarized in final result in this year. For synchronization, total 81 dairy cows selected from 4 private farms that were 38, 30, 8 and 5 in Undarmal milk, Onjin (Enkhbayer), Jargalant, and BRM School, respectively. All the dairy cows were injected intramuscular (IM) of 5 ml PGF2α in the vulva and detected estrus 2 to 3 days after PGF2α injection. Total 78 out of 81 dairy cows (96.3%) were detected estrus by only 1 time injection of PGF2α. The dairy cows that were induced estrus, inseminated with 0.5 ml dairy frozen semen by conventional AI techniques. The pregnancy diagnosis of the AI dairy cows was detected by uterus palpation after 60 days of insemination. Total 75 from 78 inseminated dairy cows (90.1%) were diagnosis pregnant. The estrus induction and pregnant rate were very effective using PGF2α injection and conventional AI techniques in Mongolia dairy cow. The results indicated that AI after estrus induction in Mongolia dairy cows could be applied to dairy breeding technology to improve the breeding efficiency and milk production.

Novel Trials to Control Harmful Algal Blooms in Seawater

Hyun?Jae Shin,Hoon Cho,Un?Sun Jin,Yun?Kyung Park,Si Wouk Kim 한국생물공학회 2010 한국생물공학회 학술대회 Vol.2010 No.10

A Study on Electrical Characteristics of Outdoor Termination with Viscosity of Insulating Oil

Jin‑Wook Choe,Seok‑Hyun Nam,Jin‑Gyu Kim 대한전기학회 2020 Journal of Electrical Engineering & Technology Vol.15 No.3

Outdoor terminations connecting overhead transmission lines and power cables comprise a stress relief cone, which is made of silicone rubber, and insulating oil in a composite or porcelain insulator. The lower the insulating oil viscosity, the greater is its ease of injection. However, the swelling and the degree of change in the electrical properties of the silicone rubber increase with a decrease in the insulating oil viscosity. Therefore, the efect of the expected change in the electrical proper‑ ties of the silicone rubber on the outdoor termination quality should be examined before choosing the insulating oil. In this study, specimens made of insulating and semiconducting silicone rubber were made to swell by impregnating them with three types of insulating oils with diferent viscosities. The AC breakdown strength of the swollen insulating specimens and the volume resistivity and relative permittivity of the semiconducting specimens were measured. The Weibull statistical analysis showed that the lower the insulating oil viscosity, the lower was the AC breakdown strength in overlapping con‑ fdence intervals. The volume resistivity and relative permittivity of the semiconducting specimens changed considerably with a change in the viscosity of the insulating oil. In particular, the volume resistivity of the specimen impregnated with the lowest viscosity insulating oil was 1.57×106 Ω m, indicating loss of semiconducting properties. Furthermore, the efect of changes in the electrical characteristics of the specimens on the outdoor termination quality was examined by performing an electric feld analysis. Compared with the other oils, impregnation with the lowest viscosity insulating oil resulted in the electric feld strength at the edge of the outer semiconducting layer increasing by 15.7%.

Differential Manifestation of Ocular Phenotypes in TALEN-mediated p19arf Knockout FVB/N and C57BL/6J mouse lines

Jin‑Sung Park,Joo‑Il Kim,Hyun‑Jin Lim,Soo‑Kyung Ryu,Euna Kwon,Kang‑Min Han,Ki‑Taek Nam,Han‑Woong Lee,Byeong‑Cheol Kang 한국유전학회 2020 Genes & Genomics Vol.42 No.9

Background p19arf, primarily known as a tumor suppressor, has also been reported to play an essential role in normal development of mouse eyes. Consistently, lack of p19arf has been associated with ocular defects, but the mixed background of the knockout (KO) mouse strain used raised a concern on the accuracy of the phenotypes observed in association with the targeted gene due to genetic heterogeneity. Object We carried out a study to investigate into the efect of genetic background on the manifestation of p19arf KO associated phenotypes. Methods We characterized the phenotypes of novel p19arf KO mouse lines generated in FVB/N and C57BL/6J using a transcription activator-like efector nuclease (TALEN) system in comparison to the reported phenotypes of three other p19arf-defcient mouse lines generated using homologous recombination. Results Ninety-fve percent of FVB/N-p19arf KO mice showed ocular opacity from week 4 after birth which worsened rapidly until week 6, while such abnormality was absent in C57BL/6J-p19arf KO mice up to the age of 26 weeks. Histopathological analysis revealed retrolental masses and dysplasia in the retinal layer in FVB/N-p19arf KO mice from week 4. Besides these, both strains developed normally from birth to week 26 without increased tumorigenesis except for a subcutaneous tumor found in a C57BL/6J-p19arf KO mouse. Conclusion Our fndings demonstrated surprisingly variable manifestation of p19arf-linked phenotypes between FVB/N and C57BL/6J mice, and furthermore between our mouse lines and the established lines, indicating a critical impact of genetic background on functional study of genes using gene targeting strategies in mice.

[P8-81] Stimulatory Effects of Aqueous Extract from Cuscuta chi­nensis Lam. on the Proliferation and Differentiation of Osteoblastic MG-63 Cells

Hyun Mo Yang,Hyun一Kyung Shin,Jin-Kyung Kim 한국식품영양과학회 2007 한국식품영양과학회 학술대회발표집 Vol.2007 No.10

학습공동체 프로그램 질과 인지적 성취 간에 집단응집성, 협력적 자기조절의 매개효과

유지현(Yu, Ji-Hyun),이숙정(Lee, Sook-Jeong),권진백(Kwon, Jin-Baek) 한국경영교육학회 2021 경영교육연구 Vol.36 No.1

[연구목적] 본 연구는 비교과 프로그램 형태의 학습공동체 운영 개선을 위해 학습공동체 프로그램 질 척도를 개발하고, 학습공동체 프로그램의 질과 인지적 성취의 관계에 집단응집성 및 협력적 자기조절의 매개효과를 검증하고자 하였다. [연구방법] 학습공동체 관련 선행연구들과 S대학에서 운영한 학습공동체 만족도 조사 및 성찰일지를 분석하여 학습공동체 프로그램 질 척도 예비문항을 개발하고, 학습공동체에 참여한 대학생 299명을 대상으로 설문조사를 실시, 분석하였다. 또한 집단응집성 및 협력적 자기조절의 매개효과를 확인하기 위해 대학생 322명을 대상으로 설문조사를 실시, 분석하였다. [연구결과] 학습공동체 프로그램 질 척도는 11개 문항, 단일요인으로 개발하였으며, 탐색적 및 확인적 요인분석, 신뢰도 계수 산출을 통해 안정적인 척도임을 확인하였다. 또한 학습공동체 프로그램 질과 인지적 성취 간에 집단응집성 및 협력적 자기조절의 매개효과가 통계적으로 유의한 것으로 나타났다. [연구의 시사점] 본 연구에서 개발한 학습공동체 프로그램 질 척도를 활용함으로써 프로그램의 내실화 및 질 관리 방안을 수립할 수 있다. 또한 집단응집성 및 협력적 자기조절의 중요성을 규명함으로써 학습공동체 프로그램 운영의 시사점을 제공하였다. [Purpose] The purpose of this study was to develop the learning community program quality scale for improving a learning community program and to verify the mediating effect of group cohesion and collaborative self-regulation on the relationship between program quality and cognitive achievement. [Methodology] A questionnaire survey of 299 university students was conducted to develop the learning community program quality scale. To confirm the mediating effect of group cohesion and collaborative self-regulation, a questionnaire survey was conducted on 322 college students. [Findings] The learning community program quality scale was developed with 11 items and a single factor, and it was confirmed to be a stable scale. And, it was found that the mediating effect of group cohesion and collaborative self-regulation between the learning community program quality and cognitive achievement was significant. [Implications] Implications for the management of learning community program to promote group cohesion and collaborative self-regulation were provided.