추황배(Pyrus pyrifolia Nakai cv. Chuhwangbae) 과피로부터 1종의 Sterol과 3종의 배당체 화합물의 단리·동정

이유건(Yu Geon Lee1),조정용(Jeong-Yong Cho),이현주(Hyun Joo Lee),이용현(Yong Hyun Lee),이상현(Sang-Hyun Lee),한태호(Tae-Ho Han),김월수(Wol-Soo Kim),박근형(Keun-Hyung Park),문제학(Jae-Hak Moon) 한국식품과학회 2013 한국식품과학회지 Vol.45 No.5

본 연구에서는 배의 유용성 증명을 위한 일환으로 배의 화학성분을 분자수준에서 밝히고자 하였다. 이에 배 과피 MeOH 추출물을 용매분획하여 얻은 EtOAc-산성 분획과 EtOAc-중성분획을 대상으로 Sephadex LH-20, silica gel, 그리고 ODS colmn chromatography와 HPLC를 이용하여 정제 및 단리하였다. 그 결과, EtOAc-산성 분획과 EtOAc-중성 분획으로부터 각각 2종씩의 화합물을 단리하였다. 단리된 화합물 1-4는 1H- 및 13C-NMR 분석을 통하여 각각 (S)-(+)-2-cis-abscisic acid O-β-D-glucopyranosyl ester (화합물 1), 1-[4-O-β-D-glucopyranosyl]phenyl ethanone(piceoside, 화합물 2), β-sitosterol (화합물 3), 그리고 β-sitosteryl 3-O-β-D-glucopyranoside (화합물 4)로 동정되었다. 단리된 3종의 배당체 화합물(화합물 1, 2, 4)들은 본 연구에 의해 배로부터 처음 동정되었으며, 화합물 3은 추황배로부터 처음 동정되었다. 본 연구결과가 배 함유 성분연구는 물론 배의 기능성 해명 연구에도 추후 중요한 기초자료로 활용되길 기대한다. We isolated and identified antioxidants from acidic and neutral ethyl acetate fractions of the peel of pear (Pyrus pyrifolia N. cv. Chuhwangbae). We isolated 4 compounds from the methanol extract, by using 3 different types of column chromatography (Sephadex LH-20, silica gel, and octadecylsilane) and preparative HPLC. We identified the isolated compounds as (S)-(+)-2-cis-abscisic acid O-β-D-glucopyranosyl ester (compound 1), 1-[4-O-β-D-glucopyranosyl]phenyl ethanone (picroside, compound 2), β-sitosterol (compound 3), and β-sitosteryl 3-O-β-D-glucopyranoside (compound 4) by nuclear magnetic resonance analysis. We are the first to report the identification of compounds 1, 2, and 4 from pear.

조기탈형을 위한 라텍스 개질 초속경 콘크리트의 개발 및 강도발현 특성

이봉학,홍창우,이주형,정원경 강원대학교 석재복합신소재제품연구센터 2001 석재연 논문집 Vol.6 No.-

현재 스틸렌-부타디엔 라텍스(styrene-butadiene latex)를 혼입한 콘크리트는 광범위하게 사용되고 있다. 교면포장용으로 라텍스 개질 콘크리트(LMC)의 사용은 일반 콘크리트와 다르지 않지만 라텍스에 의해 콘크리트의 특성을 향상시킨다. 그러나, 이와 같은 라텍스 개질 콘크리트와 다르지 않지만 라텍스에 의해 콘크리트의 특성을 향상시킨다. 그러나, 이와 같은 라텍스 개질 콘크리트는 장시간 양생을 요하는 문제로 인해 긴급을 요하는 곳에는 적용할 수 없다. 따라서 본 연구에서는 초속경시멘트를 사용한 라텍스 개질 콘크리트를 개발하고, 이에 따른 작업성 및 강도발현특성을 분석하는데 그 목적이 있다. 실험결과, 지연제와 소포제를 사용한 라텍스 개질 초속경 콘크리트(RSLMC)의 강도발현을 확인할 수 있었으며, 제안된 최적배합은 초속경성의 강도발현으로 인해 현장에서 긴급보수에 적용이 가능함을 알 수 있었다. 따라서 라텍스 개질 초속경 콘크리트는 교면포장, 포장체, 빌딩등의 보수에 적용이 가능할 것으로 판단된다. Concrete containing styrene-butadiene latex is widely used, nowadays, as a protective system for bridge. The usage of latex modified concrete (LMC) as an overlay system is not all that different from any quality concrete, but the improved properties impart to the concrete by the latex. However, this may not be used for repair works because the bridge lane could not be closed for several weeks for curing. Therefore, this study focused on the development of rapid-setting cement latex modified concrete (RSLMC), and on the investigation of workability and strength development. As a result, this study clearly validated the strength development of RSLMC by introducing a retarder and an antifoam agent. The proposed optimized concrete mixtures might be satisfactorily applied for the repair works in fields, because of its rapid strength development, respectively. Therefore, RSLMC could be used in many repair or overlay works such as bridge deck, pavement or building.

유한요소해석을 이용한 현장 덧씌우기 콘크리트의 부착강도 평가 방법 제안

이봉학,홍창우,이주형,김성환 江原大學校 産業技術硏究所 2001 産業技術硏究 Vol.21 No.B

Significant improvements in bond strength between new and existing concrete can be achieved through the modification of the new concrete by latex modification. But, no test method has been adopted as a standard to measure the bond strength between the concrete used to repair and the substrate being repaired. The performance of old and the new concrete construction defends upon band strength between old and the new concrete. Current adhesion strength measurement method is inaccurate method that ignore effect of stress concentration by shape of specimens. Therefore, this research calculates stress concentration coefficient using finite element analysis and direction tensile strength test (pull-off test). The result shows that the required core depth is 2.5cm. Elastic modulus and overlay thickness do not influence in stress concentration.

소포제 종류 및 혼입률에 따른 초속경 라텍스개질 모르타르의 역학적 특성

이봉학,홍창우,이주형,김동호 江原大學校 産業技術硏究所 2001 産業技術硏究 Vol.21 No.B

The purpose of this study was to remove the excessive air foaming which was produced in mixing the RSLMC(latex-modified concrete with rapid-setting cement) by choosing the best antifoam agent type. A series of RSLMM(latex-modified mortar with rapid-setting cement) experiments were carried out as a basic experiments for RSLMC with the main experimental variables such as antifiamer types (A, B, C, D), antifoamer contents(0, 1, 2, 3%), and latex contents(10, 15%). Air content test and compressive strength tests were carried out to measure the improved properties of RSLMM. SEM analysis, also, was carried to observe the formation of latex film. The results of RSLMM showed that the decrease of 50% air content was obtained by admixturing an antifoam agent by 1%. This made the strength enhanced and the workability be within the purposed. The best properties of compressive strengths was obtained at latex content of 15% and D antifoam agent of 1%. compressive strength increased about 32.6%. The analysis of SEM results no difference in a formation of later film.

鐵筋콘크리트 보의 附着擧動에 관한 硏究

이주형,이봉학,홍창우,김동호 江原大學校 産業技術硏究所 1998 産業技術硏究 Vol.18 No.-

Cracking is considered to be one of the important factors in determining the durability of reinforced concrete structures. When the bending stress exceeds the modulus of rupture of the concrete, cracking fom along the length of members. The total load is transferred across these cracks by the reinforcement, but the concrete between craks is still capable of carrying stresses due to the bond between steel and concrete. This phenomenon is called the tension stifening effect. The tension stiffening effect is affected by many variables, such as the bond stress, strength of concrete, interrocking of aggregate, type of steel, and dowel action of steel. Also, this tension stifening effect is usually quite significant in beams under service loading, and must be taken into account in the calculation of deflection and crack widths. In this study, the experiment was carried out on types of specimen, strength of concrete, and steel ratio and finite element analysis were compared in terms of load-deflection relationship, crack pattern.

시멘트 종류에 따른 SB 라텍스 개질 콘크리트의 강도 및 투수특성

이봉학,홍창우,이주형,김동호 江原大學校 産業技術硏究所 2001 産業技術硏究 Vol.21 No.B

This study focused on the investigation of strength development and permeability of LMC(Latex Modified Concrete) and RSLM(Rapid-Setting Cement Latex Modified Concrete) as the latex content cement types and s/c ratio changed. The compressive strength of latex modified concrete decreased slightly and the flexural strength increased quitely at 15% of latex content. This may be due to the flexibility of latex filled in voids and interconnections of hydrated cement and aggregates by a film of latex particles, respectively. The permeability test results showed that the permeability of LMC was considerably lower than that of conventional concrete. Results of chloride permeability test, for RSLMC indicated very low at an early age caused by the early formation of needle-shape ettringites and latex film.

初等敎育 理念의 探索

李學周 仁川敎育大學校 1991 論文集 Vol.25 No.1

경주두 도달법 및 척골 신경 전방 전위술을 통한 상완골 원위부 과간 골절의 치료

이광현,이성필,황규태,김주학 대한골절학회 2004 대한골절학회지 Vol.17 No.2

부순모래를 사용한 고강도 콘크리트의 배합설계에 관한 연구

이봉학,김동호,홍창우,이주형 江原大學校 産業技術硏究所 2001 産業技術硏究 Vol.21 No.A

The amount used of aggregates for concrete is increasing rapidly since the mid-1980s in Korea. The natural gravels from river are already displaced with crushed stone, and use of crushed sand as a substitute of natural river sands, also, is getting increased day by day. This paper is presented for mixture of high strength concrete using crushed sands. Mixing design of concretes alee various water-cement ratios(w/c) such as 25%, 40%, 55% and different replacement radio of crushed sands to natural sands such as 0%, 20%, 40%, 60%. As a results, it has been shown that compressive strength of concretes with w/c lower than 40% and 25% is higher than 400 kgf/cm2 and 600 kgf/cm2 respectively.

'실천'의 의미와 교육

이학주 仁川敎育大學校 1987 論文集 Vol.21 No.1