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        검색결과 350

        4.
        2021.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 병풀(Centella asiatica) 두 품종(‘자이언트 타이 거 케어’, ‘굿병풀’)의 생장 특성과 추출용매에 따른 항산화 활성 및 Triterpenoid 함량을 조사하기 위해 수행되었다. ‘자이언트 타이거 케어’와 ‘굿병풀’의 정식 후 생장 특성은 정식 41일 후 엽과 엽병의 길이 생장에서 ‘굿병풀’이 유의적으로 높았다. 하지만 이후 수확기(정식 104일 후)까지 생장속도는 유사하였다. 정식 후 104일에 수확한 ‘자이언트 타이거 케어’의 식물체 크기와 관련된 생장(엽면적, 엽병두께, 엽병 길이, 생체중)이 ‘굿병풀’보다 유의적으로 높았다. 냉수, 열수, 50% 에탄 올, 70% 에탄올 추출물의 자유라디컬 소거능과 환원능으로 평가된 항산화 활성과 총 페놀 함량은 두 품종에서 모두 70% 에탄올 추출물에서 높았다. 추출 용매별 Triterpenoid 함량을 분석한 결과, 두 품종의 주요 Triterpenoid는 Madecasoside 와 Asiaticoside로 확인되었다. 품종별 총 Triterpenoids 함량은 ‘자이언트 타이거 케어’의 50% 에탄올 추출물과 ‘굿병풀’ 의 70% 에탄올 추출물에서 가장 높았으며, ‘굿병풀’이 ‘자이언트 타이거 케어’보다 높았다. 하지만 정식 104일 후 수확량 은 ‘자이언트 타이거 케어’가 ‘굿병풀’보다 3배 많아, 동일한 재배 면적(3.3m2 ) 에서 생산 가능한 총 Triterpenoids 함량은 ‘자이언트 타이거 케어’가 2.459mg으로 ‘굿병풀’(1.103mg) 보다 약 2.2배 높았다. 따라서 항산화 활성이 가장 높고 단위면 적당 총 Triterpenoids 생산량이 높은 ‘자이언트 타이거 케어’ 를 재배하는 것이 경제적일 것으로 생각된다.
        4,000원
        12.
        2021.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study is to measure the levels of eluted and dissolved CO2, and CO, volatile organic substances and radiation composition of Cheongsong mineral water which were collected from November 2019 to July 2020 during the autumn, spring, and summer seasons at collection points located in the upper, middle and lower spring waters. Data of the upper, middle and lower spring waters include the following: the amount of eluted water (average value±standard deviation, mL/min) was 30.07±0.52, 15.03±0.16, 23.73±0.42, and the amount of CO2 gas was 1,000 ppm or more. In addition, there was no detection of CO or total volatile organic substances (TVOC) and the radiation dose was 0.08 to 0.13. μSv/h. A blank test value of 0.08 to 0.10 μSv/h, when compared with the median value, showed a high value of 0.02 μSv/h, and the uranium test results provided by the Cheongsong-gun Office were 0.0118 mg/L (date 2019.06.18) and 0.0091 mg/L (date 2020.06.04.) respectively, which was less than the permission limit of 0.03 mg/L. However, it is believed that further research using more precise devices is needed in order to guarantee the safety and health of the water.
        4,000원
        14.
        2020.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this paper, the hybrid prefabricated retrofit method is suggested and examined. Six specimens were manufactured in order to evaluate their flexural performance of RC beams. Test parameters include the added beam depth, the thickness of bottom plate, the number of the steel plate with openings. The effects of these parameters on the flexural performance of reinforced concrete beams were examined. The load-deflection behavior and modes of cracks are presented from the test results. At the test result, the flexural capacity and the ductility of the hybrid prefabricated retrofit method was increased satbly. Also, comparing the flexural performance of RC beam and retrofitted RC beams, it was increased that the flexural strength is about 3.3 times, the ductility is about 2.55 times, and energy dissipation capacity is about 7.34 times.
        4,000원
        15.
        2020.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study is to investigate the densification behavior and the corresponding microstructural evolution of tantalum and tantalum-tungsten alloy powders for explosively formed liners. The inherent inhomogeneous microstructures of tantalum manufactured by an ingot metallurgy might degrade the capability of the warhead. Therefore, to overcome such drawbacks, powder metallurgy was incorporated into the near-net shape process in this study. Spark plasma-sintered tantalum and its alloys with finer particle sizes exhibited higher densities and lower grain sizes. However, they were contaminated from the graphite mold during sintering. Higher compaction pressures in die and isostatic compaction techniques also enhanced the sinterability of the tantalum powders; however, a full densification could not be achieved. On the other hand, the powders exhibited full densification after being subjected to hot isostatic pressing over two times. Consequently, it was found that the hot isostatic-pressed tantalum might exhibit a lower grain size and a higher density as compared to those obtained in previous studies.
        4,000원
        17.
        2020.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this paper, the hybrid prefabricated retrofit method that improve structural performance and reduce construction period was developed by using a finite element analysis. The hybrid prefabricated retrofit method consist of a Z-shaped side plate, a L-shaped lower plate, and a bottom plate containing an steel plate with openings. This shape has advantage that a retrofit method is possible regardless of the size of the beams and a follow-up process such as reinforcement bars placing are not required. The finite element analysis of hybrid Prefabricated retrofit method showed the most ideal stress distribution when the thickness of bottom plate was 10mm, the thickness of the L-shaped lower plate was 5mm, the thickness of the Z-shaped side plate was 2.5mm, and the bolt spacing was 200mm. The bending strength equation of Hybrid prefabricated retrofit method was proposed through the plastic stress distribution method in KDS 41 31 00. The result of Comparison the proposed equation with the finite element analysis, it is determined that the design of hybrid prefabricated retrofit method is possible through the KDS 41 31 00.
        4,000원
        18.
        2020.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study is an application of Lee’s Menu Engineering (LME) method for menu analysis on the eight kinds of pizza selected from 17 kinds of pizza served by an Italian restaurant near by the Keimyung College University campus. The eliminated nine items were in the third quadrant or below the trend line. The LME method is more efficient than generally used methods such as the Miller, Kasavana & Smith, Uman, Pavesic and Merricks & Jones method. The LME method comprises reference lines and four quadrants created by x, y axes and its average values. The x and y axes comprise the sales ratio (MM%, percentage of the Menu Mix) and the weighted contribution margin (WCM%, percentage of the Weighted Contribution Margin) respectively. The obtained results are such that total sales increased by 1.59% from 58,747,200 won to 59,684,000 won, despite the decrease in sales volume. Total contribution margin also increased from 35,248,320 won to 35,810,400 won. The trend line also shows from y=0.9147x (R2=0.703) to y=0.9944x (R2=0.9893). These results indicate that the LME method is superior in practical applications.
        4,000원
        20.
        2019.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 고구마(Ipomoea batatas L.) 수확 후 버려지는 잔재물의 활용가치를 위해 이들로부터 추출한 발효 추출물과 열수 추출물의 생리활성과 세포독성을 분석 하였다. 추출물의 pH는 모두 산성을 나타내었고, 유기물 함량은 발효 추출물과 열수 추출물에서 각각 0.98%와 0.97%로 비슷하게 나타내었다. 다량원소 중 인산, 칼륨, 칼슘, 마그네슘 성분의 함량은 열수 추출물에서 발효 추출물보다 모두 높게 나왔고, 질소 함량만 두 추출물에서 동일하게 나왔다. 미량원소 함량은 아연을 제외하고 발효 추출물보다 열수 추출물에서 높게 나타내었다. 총 폴리페놀 함량은 열수 추출물에서 60.5±2.7 mg/g로서 발효 추출물의 총 폴리페놀 함량의 22.7±4.2 mg/g 보다 37.8 mg/g 높은 함량을 나타내었다(p<0.05). 총 플라보노이드 함량은 열수 추출물에서 50.7±2.7 mg/g로서 발효 추출물의 함량인 14.0±2.1 mg/g 보다 36.7 mg/g 높은 함량을 나타내어 총 폴리페놀 함량과 마찬가지로 열수 추출물이 발효 추출물보다 높은 함량을 나타내었다(p<0.05). DPPH와 ABTS radical 소거능력은 모두 열수 추출물에서 발효 추출물 보다 높은 항산화력을 보였다(p<0.05). MTT assay를 이용한 추출물의 세포독성 실험에서는 두 추출물의 모든 농도에서 세포독성이 미약한 것으로 확인되었다. 따라서 고구마 수확 후 잔재물의 추출물이 향후 각종 바이오 소재로 이용 시에도 큰 문제가 없을 것이라 판단된다.
        4,200원
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