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( Bong-kyu Song ),( Kyeng Min Kim ),( Kang-duk Choi ),( Wan-taek Im ) 한국미생물생명공학회(구 한국산업미생물학회) 2017 Journal of microbiology and biotechnology Vol.27 No.7
The ginsenoside Rh2 has strong anti-cancer, anti-inflammatory, and anti-diabetic effects. However, the application of ginsenoside Rh2 is restricted because of the small amounts found in Korean white and red ginsengs. To enhance the production of ginsenoside Rh2-MIX (comprising 20(S)-Rh2, 20(R)-Rh2, Rk2, and Rh3 as a 10-g unit) with high specificity, yield, and purity, a new combination of enzymatic conversion using the commercial enzyme Viscozyme L followed by acid treatment was developed. Viscozyme L treatment at pH 5.0 and 50°C was used initially to transform the major ginsenosides Rb1, Rb2, Rc, and Rd into ginsenoside F2, followed by acid-heat treatment using citric acid 2% (w/v) at pH 2.0 and 121°C for 15 min. Scale-up production in a 10-L jar fermenter, using 60 g of the protopanaxadiol-type ginsenoside mixture from ginseng roots, produced 24 g of ginsenoside Rh2-MIX. Using 2 g of Rh2-MIX, 131 mg of 20(S)-Rh2, 58 mg of 20(R)-Rh2, 47 mg of Rk2, and 26 mg of Rh3 were obtained at over 98% chromatographic purity. Then, the anti-cancer effect of the four purified ginsenosides was investigated on B16F10, MDA-MB-231, and HuH-7 cell lines. As a result, these four rare ginsenosides markedly inhibited the growth of the cancer cell lines. These results suggested that rare ginsenoside Rh2-MIX could be exploited to prepare an anti-cancer supplement in the functional food and pharmaceutical industries.
Direct-Connect 초음속 연소기 내 초음속 유동 형성과정에 대한 수치해석
정승민(Seong-Min Jeong),한형석(Hyunh-Seok Han),성부경(Bu-Kyeng Sung),이은성(Eun-Sung Lee),최정열(Jeong-Yoel Choi) 한국항공우주학회 2020 韓國航空宇宙學會誌 Vol.48 No.11
본 연구에서는 직접 연결식 초음속 연소기에서 설계점을 만족하는 초음속 유동의 형성유무 및 안정화 소요시간을 확인하기 위한 수치해석이 수행되었다. 이를 위하여 연소식 공기 가열기 하류의 고압 유동이 초음속 연소기로 전파되며 초음속 유동장을 형성해가는 과정을 살펴보았다. 압력 및 온도 분석을 통해, 초음속 유동장이 설계점인 마하수 2.0, 1,000 K을 만족하며, 최소 4.0 ㎳의 안정화 시간이 필요함을 확인하였다. 따라서 초음속 연소시험에서 연료분사 이전에 유동 안정화에 필요한 시간을 고려해야 함을 알 수 있었다. In this study, a numerical analysis was performed to confirm the formation of supersonic flow and the stabilization time satisfying the design condition in a Direct-connect supersonic combustor. The process was examined in which the high-pressure gas of vitiation air heater propagates downstream to the supersonic combustor and forms a supersonic flow field. It was confirmed through the analysis of pressure and temperature that the supersonic flow field satisfies the design points of Mach number 2.0 and 1,000 K, and requires a minimum of 4.0 ㎳ for stabilization. These results indicate that the time required for the supersonic flow field stabilization should be taken into account when testing for the supersonic combustion experiment.
당량비 및 공동 형상에 따른 직접 연결식 초음속 연소기의 연소특성
정승민(Seung-Min Jeong),한형석(Hyung-Seok Han),성부경(Bu-Kyeng Sung),이은성(Eun-Sung Lee),최정열(Jeong-Yeol Choi) 한국추진공학회 2020 한국추진공학회 학술대회논문집 Vol.2020 No.11
본 연구에서는 당량비 및 형상조건에 따른 직접 연결식 초음속 연소기의 연소특성을 확인하기 위한 수치해석이 수행되었다. 당량비 0.55, 0.60 조건의 결과에서, 저주파수 초음속 연소불안정이 포착되었다. 수 ms의 주기를 가지며 격리부 상류~연료분사 영역을 오가는 유동이 초음속 연소기의 연소불안정을 야기하는 것으로 판단된다. 압력장에 대한 DMD 분석을 통해, 이러한 저주파수 거동이 격리부 영역과 연료분사 영역으로 명확히 구분되어 진동하는 것을 확인하였다. In this study, a numerical analysis was performed to investigate the combustion characteristics of Direct-connect supersonic combustor according to the equivalence ratio and shape conditions. Low frequency supersonic combustion instability was detected under the result of a global equivalence ratio condition at 0.55, 0.60. It is considered that the flow between the upstream of the isolator and the fuel injection region with several ms periods causes combustion instability in the supersonic combustor. Through the DMD analysis of the pressure field, it was confirmed that this behavior was clearly separated from the fuel injection area in the low frequency band and vibrated. Through the DMD analysis of the pressure field, it was confirmed that these low-frequency behaviors were clearly divided into the isolator region and the fuel injection area and oscillated.