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하이브리드 섬유보강 RC 보의 휨 거동 및 경제성 평가
이기연(Lee, Ki-Yeon),나현준(Na, Hyun-Jun),이은규(Lee, Eun-Gyu),양근혁(Yang, Keun-Hyeok) 대한건축학회 2023 대한건축학회 학술발표대회 논문집 Vol.43 No.2
In this study, an assessment of the tensile behavior and cost-effectiveness based on the types of hybrid fibers was conducted. The types of hybrid fibers included micro steel fibers (hooked-end type), conventional steel fibers (hooked-end type), and polypropylene fibers (PP fibers). When these fibers were incorporated at a 1% ratio under the same cross-sectional conditions, both the maximum tensile strength and maximum moment were highest when micro steel fibers were added. The toughness ratio was also consistent. The cost-effectiveness was compared by incorporating fibers to achieve the same strength. When conventional steel fibers were added at a ratio of 1.14% and micro steel fibers were added at a ratio of 1%, the costs were identical.
이기연(Ki Yeon Lee),홍수영(Soo Young Hong),정혜정(Hye Jeong Jeong),이재형(Jae Hyoung Lee),임상현(Sang Hyun Lim),허남기(Nam-Kee Heo),김성문(Songmun Kim),김희연(Hee-Yeon Kim) 한국식품영양과학회 2014 한국식품영양과학회지 Vol.43 No.12
가시오갈피 잎에 함유된 α-glucosidase의 저해 활성 물질의 분리를 위하여 가시오갈피 잎 80% 에탄올 추출물을 극성유기 용매를 사용하여 순차 분획하고 각 분획층을 α-glucosidase의 저해 활성 효과를 측정한 결과, EtOAc 층이 68.05%로 가장 높은 저해 활성을 나타내었다. EtAOc 분획층을 MPLC를 이용하여 fractionation-directed isolation을 수행하고 최종적으로 α-glucosidase 저해 활성이 93.60%로 가장 우수하게 나타난 EAHC 분획물을 얻었다. EAHC 분획물을 prep-LC/MS로 분석하여 EAHCA와 EAHCB로 분리ㆍ정제하였다. EAHCA 분획물의 화학구조를 구명하기 위하여 ¹H-NMR, <SUP>13</SUP>C-NMR로 분석한 결과, 분자량 464.38 g/㏖, 화학구조식 C21H20O12인 hyperoside로 확인되었다. EAHCB 분획물의 화학구조를 구명하기 위하여 1H-NMR, <SUP>13</SUP>C-NMR로 분석한 결과, 분자량 464.38 g/㏖, 화학구조식 C21H20O12인 isoquercetin으로 확인되었다. 본 연구 결과, 가시오갈피 잎으로부터 분리ㆍ동정된 hyperoside와 isoquercetin은 α-glucosidase의 저해 활성 물질을 가진 화합물로 향후 혈당조절용 건강식품 또는 치료제 개발을 위한 물질로 활용될 수 있을 것으로 판단된다. In the present investigation, the anti-diabetic potential of 80% ethanol extract of Eleutherococcus senticosus leaves (EEES) was examined based on α-glucosidase inhibitory activities. EEES was sequentially fractionated with n-hexane, chloroform, ethyl acetate (EtAOc), n-butanol, and H₂O. Of the various fractions, EtAOc fraction effectively inhibited α-glucosidase activity by 68.05%. Therefore, EtAOc fraction was selected for further isolation and identification studies. EtAOc fraction was separated by medium pressure liquid chromatography with silica and ODS gel to yield eight fractions (EAA~EAH). Based on the results of α-glucosidase inhibitory activity, EAH fraction was re-chromatographed to yielded four more fractions (EAHA~EAHD). Of these, EAHC fraction showed higher α-glucosidase inhibitory activity of 93.60%. EAHC fraction was re-chromatographed and yielded EAHCA and EAHCB fractions. Further, identification and chemical structures of these two fractions were analyzed using ¹H-NMR, <SUP>13</SUP>C-NMR, and mass spectra data. Based on the results of the spectral data, the isolated compounds were identified as hyperoside and isoquercetin. Results of the present study indicate that the isolated compounds, hyperoside, and isoquercetin from leaves of E. senticosus could be used for the development of new anti-diabetic drugs.
비접촉 전압위상 검출 기술을 이용한 무정전 절연저항 측정 방법에 관한 연구
이기연(Ki-Yeon Lee),문현욱(Hyun-Wook Moon),김동우(Dong-Woo Kim),임용배(Young-Bae Lim),최동환(Dong-Hwan Choi),김용혁(Yong-Hyeok Kim) 대한전기학회 2018 전기학회논문지 Vol.67 No.8
In this paper, measurement techniques are presented to test the performance of insulation without interruption if it is difficult to measure insulation resistance. Especially, non-contact voltage phase detection techniques have been developed that can be applied in environments where it is difficult to find voltage measurement locations such as component receptors. The performance verification of the non-interrupting insulation resistance measuring devices has been tested against existing products using standard calibration equipment and test jigs. The validation confirmed performance within 2 % for direct contact type and within 10 % for non-contact type. In addition, the procedure to make continuous insulation test using the equipment was proposed.