A Study on the Analysis of 20,000rpm Heavy-Cutting Spindle for Precision Machining

오남석(Nam-Seok Oh),김동현(Dong-Hyeon Kim),이춘만(Choon-Man Lee) Korean Society for Precision Engineering 2015 한국정밀공학회지 Vol.32 No.1

A spindle unit is very important in machine tools. It has a direct effect on machining accuracy. The static and dynamic characteristics of the spindle unit should be considered in the initial design stage for manufacturing of precision product. This study describes an investigation for deriving design stability of a 20,000rpm heavy-cutting spindle for precision machining. Static and dynamic characteristics of the spindle, such as deformation, stress, natural frequency and mode shapes are analyzed using finite element analysis. The 20,000rpm heavy-cutting spindle is confirmed that it is successfully designed through finite element analysis.

정보보호 수준평가 방법 개선에 관한 연구

오남석(Nam-Seok Oh),한영순(Young-Soon Han),엄찬왕(Chan-Wang Eom),오경석(Kyeong-Seok Oh),이봉규(Bong Gyou Lee) 한국전자거래학회 2011 한국전자거래학회지 Vol.16 No.2

본 논문은 정보통신 서비스 제공기관 및 업체가 현재의 보안 상태를 단계별로 등급화된 지표에 따라 평가하고, 지속적으로 정보보호 수준을 상위 단계로 개선해 나갈 수 있도록 정보보호 수준평가방법을 제안하였다. 이를 위해 SP800-26의 17개 분야, SP800-53의 3개 분야, ISMS의 15개 분야, ISO27001의 10개 분야를 분석하여 중복적인 분야를 제거하고, 관련 전문가 회의를 통해 12개 평가분야와 SP800-26의 221개 항목, SP800-53의 17개 항목, ISMS의 137개 항목, ISO27001의 127개 항목을 분석하여 54개 평가항목을 도출하였다. 또한, 54개 평가항목에 대한 수준을 5단계로 구분된 지표에 따라 각각 평가하고, 각 평가분야별로 등급을 결정할 수 있도록 하였다. 아울러, 개발된 평가항목과 등급 등이 실제 운영환경에 잘 적용될 수 있도록 운영상에서 발생할 수 있는 문제점을 사전에 분석하고, 이를 고려한 수준평가의 효과적인 7가지 수행방안을 제시하였다. 본 논문에서 제안한 정보보호 수준평가 방법은 계량화된 데이터를 통해 해당조직의 정보보호 대책을 수립할 수 있도록 지원하며, 조직관리자들의 정보보호 목표수준 설정을 위한 자료로 활용되어 국가적 차원의 정보보호 수준 향상에 기여할 수 있을 것이다. In order for agencies and companies at the IT service industry to check as well as to upgrade the current status of their information security programs, this paper suggests the assessment method for information security levels. The study developed 12 assessment fields and 54 assessment items derived from domestic and foreign cases including SP800-26, SP800-53, ISMS, and ISO27001. It categorized 54 assessment items into 5 levels for determining information security levels. Also, the study presents 7 strategies for performing their efficient evaluations. The proposed method and process in this paper can be useful guidelines for improving the national information security level.

UV살균과 초고압살균에 의한 당근주스의 저장성 비교

오남석 ( Nam Seok Oh ),김민영 ( Min Young Kim ),장귀영 ( Gwi Young Jang ),백소윤 ( So Yune Baek ),정미연 ( Mi Yeun Joung ),강태수 ( Tae Su Kang ),이준수 ( Junsoo Lee ),정헌상 ( Heon Sang Jeong ) 한국식품영양학회 2017 韓國食品營養學會誌 Vol.30 No.5

The objective of this study was to investigate the non-thermal sterilization effect of methods such as high hydrostatic pressure (HHP) and UV-irradiation (specifically with regard to the storage stability and shelf-life of carrot juice. The microbial counts of the non-sterilized product increased from 5.51 to 7.34 log CFU/mL up to the fifth day, and then decreased to 5.46 log CFU/mL at six days. UV-irradiation was increased from 2.37 to 4.92 log CFU/mL. HHP was maintained under the 3 log CFU/mL. The pH of UV-irradiation and HHP was maintained withing the range of 6.29~6.30 and 6.20~6.22 during storage. However, the pH arising from non-sterilization decreased from 6.31 to 4.49. The color of non-sterilization changed significantly during storage, but UV-irradiation and HHP were similar during storage. The β- carotene content of non-sterilization was noted to have decreased from 269.45 to 65.19 μg/mL during storage. The UV- irradiation and HHP decreased from 263.46 and 268.35~281.16 μg/mL to 243.42 and 244.09~269.29 μg/mL, respectively. In conclusion, these findings suggest that HHP can be used for the pasteurization, or sterilization, of carrot juice and the optimal condition is two minutes.

에멀전 방식의 고분자 분산형 액정의 전기 광학 특성에 미치는 액적 크기 분포의 영향

유희상,오남석,김안,권순범,Yoo, Hee Sang,Oh, Nam-Seok,Yan, Jin,Kwon, Soon-Bum 한국전기전자재료학회 2015 전기전자재료학회논문지 Vol.28 No.7

We established the emulsion method using membrane filter with precise control of LC droplet distribution in PDLC. PDLC cells with various LC droplet size distributions such as single droplet sizes of $1.0{\mu}m$, $1.9{\mu}m$ and $3.5{\mu}m$, the mixture of two different LC droplet sizes and the mixture of three different LC droplet sizes were fabricated and the electro-optical properties of the emulsion type PDLC cells with various droplet size distribution were investigated. In the appropriate droplet size range, the PDLCs with the single droplet sizes distributions have good electro optical properties than those with the mixture of three different LC droplet sizes. In addition, the PDLC cells with the mixture of two different LC droplet sizes have the better electro optical properties than those with single droplet sizes distribution. The PDLC cell with dual droplet size distribution of $1.0+1.9{\mu}m$ shown the best electro optical properties than the PDLC cells with other size distributions. This method enabled us to find the proper LC droplet size distribution for achieving both high transmittance and contrast ratio.

특집1 토론문

이상승(Yi Sang Seung),김형찬(Kim Hyung Chan),이상규(Rhee Sang Kyu),오남석(Oh Nam Seok),박대수(Park Dae Soo),하성호(Ha Seong Ho),김형곤(Kim Hyung Gon) 서울대학교 공익산업법센터 2008 경제규제와 법 Vol.1 No.2

발아에 따른 팥의 유리형 및 결합형 기능성분 변화

김민영(Min Young Kim),장귀영(Gwi Yeong Jang),오남석(Nam Seok Oh),백소윤(So Yune Baek),김길호(Kil Ho Kim),김경미(Kyung Mi Kim),김홍식(Hongsik Kim),이준수(Junsoo Lee),정헌상(Heon Sang Jeong) 한국식품영양과학회 2017 한국식품영양과학회지 Vol.46 No.8

본 연구에서는 발아에 의한 팥의 기능성분 변화를 살펴보기 위하여 6일 동안 발아시키면서 유리형 및 결합형 폴리페놀, 플라보노이드, 페놀산 및 안토시아닌의 변화를 분석하였다. 유리형 폴리페놀 및 플라보노이드 함량은 발아기간이 증가함에 따라 각각 약 2.6배 및 5배 정도 증가하였으며, 결합형 폴리페놀 및 플라보노이드 함량은 발아 초기 감소하였다가 발아 3일 및 2일 이후 각각 증가하였다. 발아기간에 따른 구성 페놀산의 변화의 경우 ferulic acid, veratric acid, hesperidin, salicylic acid, naringenin 및 hesperidin과 총 페놀산은 유리형 및 결합형 페놀산 함량이 모두 증가하였지만, 안토시아닌 및 안토시아니딘은 침지 및 발아과정에서 손실되어 감소하였다. 본 연구 결과 팥을 발아시킬 경우 폴리페놀, 플라보노이드 및 페놀산 함량이 증가함에 따라 팥에 함유된 기능성분의 이용성을 증대시키기 위해서는 발아공정의 적용이 효과적이라고 판단된다. This study was performed to investigate the changes between free and bound forms of bioactive compounds in germinated adzuki bean. Adzuki bean was germinated at 25°C for 6 days, and then free and bound forms of bioactive compounds were extracted. Total free polyphenol and flavonoid contents in of raw adzuki bean increased from 0.91 mg/g and 0.60 mg/g in before germination to 2.37 mg/g and 3.03 mg/g in at 6 days after germination, respectively. Bound polyphenol, flavonoid, and phenolic acid contents also increased with increasing germination periods, whereas bound polyphenol and flavonoid contents slightly reduced in at 2 days after germination. The total phenolic acid contents, including ferulic acid, veratric acid, hesperidin, salicylic acid, naringenin, and hesperidin, increased during germination, and germination process can convert compounds to phenolic acid via anabolism and catabolism. Total anthocyanin and anthocyanidin contents of adzuki bean decreased during germination due to hydration by water during soaking or enzyme activation of anthocyanase during germination. These results suggest that the germination process increased utilization of functional compounds such as phenolic compound and isoflavones in black soybean.

품종 및 입도별 보리 맥강의 기능성분 함량

백소윤(So Yune Baek),이윤정(Yoon Jeong Lee),장귀영(Gwi Young Jang),김민영(Min Young Kim),오남석(Nam Seok Oh),이미자(Mi Ja Lee),김현영(Hyun Young Kim),이준수(Jun Soo Lee),정헌상(Heon Sang Jeong) 한국식품영양과학회 2017 한국식품영양과학회지 Vol.46 No.10

보리 도정 시 발생되는 부산물(맥강)의 이용방안을 모색하기 위하여 5가지 품종의 쌀보리 보석찰(유색 찰성), 흰찰쌀(찰성), 다한(메성), 흑광(유색), 흑누리(유색)를 23%로 도정한 다음 입도별(<60 mesh(fraction Ⅰ), 60~100 mesh(fraction Ⅱ), >100 mesh(fraction Ⅲ)로 분획 후, 기능성분 함량에 대해 분석하였다. 베타글루칸의 함량은 모든 품종에서 fraction Ⅱ에서 가장 높게 나타났으며, 다한과 흑누리에서 높은 함량을 나타내었다. 아라비노자일란은 fraction Ⅲ에서 가장 낮은 함량을 보여 입도가 큰 분획물을 이용하는 것이 아라비노자일란 고함유 분획물을 얻을 수 있었다. 총 폴리페놀 및 플라보노이드는 모든 품종에서 fraction Ⅱ에서 가장 높은 함량을 나타내었으며, 항산화력과 라디칼 소거능 역시 fraction Ⅱ에서 가장 좋은 활성을 나타내어 비슷한 경향을 나타내었다. 분석한 모든 기능성분의 함량이 높았던 fraction Ⅱ는 보리의 겨층 부분과 배유층 부분이 적절히 혼입된 분획물로 판단되기 때문에 맥강의 기능성 식품 소재화를 위한 맥강을 선정할 때 fraction Ⅱ를 활용하는 것이 좋을 것으로 판단되었다. 이러한 결과는 보리 도정 부산물의 효율적인 이용을 위하여 품종 및 입도별 분류를 통해 유용성분이 고함유되어 있는 층을 얻고, 이를 활용한 식품 기능소재로서의 가능성을 확인하였다. This study evaluated the functional components of barley bran with different particle sizes and cultivars (Dahan, Hinchalssalbori, Heukgwang, Huknuri, and Boseokchal). Barley bran divided into fractions Ⅰ (<60 mesh), Ⅱ (60∼100 mesh), and Ⅲ (>100 mesh) was collected as pearling by-products produced by an industrial process consisting of consecutive barley pearlers. Total β-glucan contents of all cultivars were especially highest in fraction Ⅱ. Total arabinoxylan was the highest in barley bran from Boseokchal in fraction Ⅱ. Total polyphenol contents were the highest in bran from Boseokchal and Hinchalssal in fraction Ⅱ, and contents ranged of 5.61∼7.00 and 4.24∼6.58, respectively. Total flavonoid contents of all cultivars were especially highest in fraction Ⅱ. 2,2’-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activities ranged from 2.78∼7.53 mg L-ascorbic acid (AA) eq/g and 2.24∼4.83 mg AA eq/g, respectively. ABTS and DPPH radical scavenging activities were the highest in barley bran from Dahan in fraction Ⅱ. In this study, fraction Ⅱ showed enriched functional components and has the best particle size range for enriched antioxidant activities. These results provide useful data for selection of appropriate cultivars and particle size of bran to achieve high quality barley processing.

CuO를 열확산시킨(Sr.Ca)TiO_(3) 입계층 커패시터의 전기적 특성

최운식,강재훈,오남석 대불대학교 2002 大佛大學校大學院 硏究論文集 Vol.- No.1

In this paper, the Sr_(1-x)Ca_(x)TiO_(3)(0≤x≤0.2)-based grain boundary layer ceramics were fabricated to measured dielectric properties with the sintering temperature and the thermal treatment time. The sintering temperature and time were 1420∼1520℃, 4hours, and the thermal treatment temperature and time of the specimen were 1150℃, 1, 2, 3,hours, respectively. The structural and the dielectric properties were investigated by SEM, X-ray, HP4194A and K6517. The average grain size was increased with increasing the sintering temperature, but decreased to 15㏖% with increasing content of Ca. X-ray diffraction analysis results showed that all specimens were the cubic structure, the main peaks were of Ca. The appropriate thermal treatment temperature and time of CuO to obtain dielectric properties of ε_(γ)>50000, tan δ<0.05 and ΔC<±10% were 1150℃ and 2hours, respectively.