선박엔진의 Supply Unit용 SNCM420H의 절삭특성

최원식,성봉수,강창원,문희준,권주리,Choi, Won-Sik,Sung, Bong-Soo,Kang, Chang-Won,Mun, Hee-Joon,Kwon, Ju-Ri 한국생산제조학회 2010 한국생산제조학회지 Vol.25 No.5

SNCM420 steel is one of the cam shaft materials which are used in the supply unit for ship engine cam shaft. In this study the assessment of cutting behavior was conducted for the SNCM 420 steel and SM45C steel with various cutting conditions as depth of cut 0.5, 1.0, 1.5, 2.0mm and feed rate 0.1~0.3m/rev. The controlled chip was produced in feed rate 0.2, depth of cut 1.0 for SNCM420 and feed rate 0.2, depth of cut 2.0 for SM45C. There is no difference cutting force between SM45C and SNCM420 steels.

한국산 옻나무로부터 추출.분리한 생리활성 물질들의 항산화 효과 및 세포독성

최원식,김동길,이영행,김장억,이성은,Choi, Won-Sik,Kim, Dong-Kil,Lee, Young-Haeng,Kim, Jang-Eok,Lee, Sung-Eun 한국응용생명화학회 2002 한국농화학회지 Vol.45 No.3

한국산 옻나무의 메탄올추출물과 유기용매 분획의 항산화 효과를 조사하였다. 항산화 효과는 수소공여 억제능, 과산화지질 형성 억제능, xanthine oxidase저해 활성과 아질산염 소거능으로 측정한 결과, ethyl acetate 분획이 가장 뛰어난 효과를 나타내었다. 이 분획의 생리활성 물질을 분리하기 위하여, rotatory locular counter current chromatography(RLCCC), Sephadex LH-20 column chromatograpy와 HPLC등의 방법을 사용하여, 1,2,3-trihydroxybenzene, methyl 3,4,5-trihydroxybenzoat와 3,4,5-trihydroxybenzoic acid를 분리하였다. 이중 methyl 3,4,5-trihydroxybenzoate는 butylated hydroxyanisole(BHA)이나 butylated hydroxytoluene(BHT)보다도 강한 항산화 효과를 나타내었다. 그러나 세포독성 실험에서는 이들 물질들이 암세포주에 대하여 활성이 높지 않았다. 이상의 결과로 methyl 3,4,5-trihydroxybenzoate은 뛰어난 항산화 효과를 지닌 식품첨가물로서의 이용 가능성을 제시할 수 있다. Antioxidative activities of solvent fractions obtained from Korean Rhus vernicifera, being used in food industry and as a traditional medicine, were examined by the methods of DPPH scavenging activity, inhibitory effect on autooxidation of linoleic acid, nitrite scavenging activity and the inhibitory effect on xanthine oxidase activity. Ethyl acetate fraction showed potent antioxidative activities. Three compounds were isolated from the ethyl acetate fraction by rotatory locular counter current chromatography (RLCCC), Sephadex LH-20 column chromatography and HPLC. The isolated compounds were 1,2,3-trihydroxybezene, methyl 3,4,5-trihydroxybenzoate and 3,4,5-trihydroxybenzoic acid determined by GC/MS and, $^1H$ and $^{13}C$ NMR. Among the isolated compounds, methyl 3,4,5-trihydroxybenzoate showed the strongest antioxidative activity than artificial antioxidants, BHA and BHT in various methods. However, these isolated compounds did not show cytotoxicity effects on the human cancer cell lines. Therefore, we may suggest that methyl 3,4,5-trihydroxybenzoate can be used as a food additive possessing the potent antioxidative activity.

6${\beta}$-Bromopenicillanate로부터 6-(Carboxymethylthio) penicillanic Acid 유도체의 합성

최원식,이영행,이채호,Won-Sik Choi,Young-Haeng Lee,Chai-Ho Lee 대한화학회 1991 대한화학회지 Vol.35 No.5

6${\beta}$-bromopenicillanic acid(4a)와 p-nitrobenzylbromide, 3-bromophthalide, chloromethylpivalate 및 1-chlorodiethylcarbonate의 반응으로 6${\beta}$-bromopenicillanates(4b~4e)을 합성하였으며, 6${\beta}$-bromopenicillanic acid(4a)와 그의 ester(4b~4e)를 thioglycolic acid와 친핵성 치환반응시켜 새로운 $\beta$-lactam계 화합물인 6-(carboxymethylthio)penicillanic acid(5a)와 그의 ester(5b~5e)를 얻었다. Reaction of 6${\beta}$-bromopenicillanic acid(4a) with p-nitrobenzylbromide, 3-bromophthalide, chloromethylpivalate and 1-chlorodiethylcarbonate afforded 6${\beta}$-bromopenicillanates(4b~4e). New ${\beta}$-lactam compound, 6-(carboxymethylthio)penicillanic acid(5a) and the other esters(5b~5e) were prepared by nucleophilic substitution reaction of 6${\beta}$-bromopenicillanic acid(4a) and the other esters(4b~4e) with thioglycolic acid.

Friction Characteristics of CNx Coated Dimple Pattern with Hexagonal Array

최원식,Choi, Won-Sik,Umehara, Noritsugu Korean Tribology Society 2011 한국윤활학회지(윤활학회지) Vol.15 No.3

In this study, we examined the friction characteristics of a dimple pattern on a carbon nitride coating. The study was conducted with a hexagonal array 40 ${\mu}m$ dimple pattern on a steel bearing containing a CNx coating. The area density of the dimple patterns were varied between 5% and 25%, the speed was varied from 0.06-0.26 m/s, and the load was varied between 20-100N. In general, we found that as the velocity increased, the friction coefficient increased. Furthermore, the friction coefficient was lowest at a load of 40N. The friction coefficient of the non-coated specimen was 0.025-0.15; on the other hand, the friction coefficient of the coated specimen was 0.002-0.02. Thus, we determined that the coated materials could reduce the friction coefficient by a factor of 7.5.

Coenzyme Qn 유도체들의 합성

최원식,어진용,남석우,김재훈,이영행,Choi, Won-Sik,Eo, Jin-Yong,Nam, Seok-Woo,Kim, Jae-Hoon,Lee, Young-Haeng 대한화학회 2007 대한화학회지 Vol.51 No.6

Tribological Characteristics in $40{\mu}m$ Dimple Pattern for Hexagonal Array

최원식,채영훈,Choi, Won-Sik,Chae, Young-Hoon,Umehara, Noritsugu Korean Tribology Society 2009 한국트라이볼로지학회지 (Tribol. Lubr.) Vol.17 No.5

본 연구에서는 pin-on-disk 마찰 시험기를 통하여 Hexagonal 배열 $40{\mu}m$ Dimple 패턴의 효과를 실험하였다. 마찰 실험은 미끄럼 속도가 $0.06{\sim}0.34m/s$로 하였으며 마찰하중은 $20{\sim}100\;N$의 범위로 하였고, Dimple의 밀도는 $10{\sim}25%$의 범위로 제작하여 실험을 행하였다. 일반적으로 속도가 증가하고 하중이 감소할수록 마찰계수는 감소하는 경향을 나타내었으며, Dimple에 의한 마찰저감 효과는 속도가 $0.14{\sim}0.26m/s$의 범위에서 나타났다. $40{\mu}m$ Hexagonal 배열 Dimple 패턴의 마찰 특성에서는 밀도가 12.5%에서 가장 좋은 경향을 나타내었다.

trans -(3R,5S)-Atorvastatin Ca의 합성 및 Rat에서 고지방식이로 유도된 고지혈증 치료효과

최원식(Choi, Won-Sik),남석우(Nam, Seok-Woo),이경락(Lee, Gyung-Rak) 한국산학기술학회 2011 한국산학기술학회논문지 Vol.12 No.11

고지혈증 치료제인 cis-(3R,5R)-atorvastatin Ca (1)은 4개의 입체이성질체가 있으며, 각각의 이성질체들을 선 택적으로 제조한다는 것은 매우 어려운 일이다. 본 연구에서는 입체이성질체 중의 하나인 trans-(3R,5S)-atorvastatin Ca (7)을 초산에서 3,5-diketo atorvastatin ester (3)를 Me4NHB(OAc)3을 사용하여 환원시켜 cis-(3R,5R) (4)과 trans-(3R,5S)-atorvastatin ester (5)를 각각 1.5%와 98.5%의 비율로 입체선택적으로 제조할 수 있었다. 또한, 고지혈증 치료제인 cis-(3R,5R)-atorvastatin Ca (1)과 그의 입체이성질체인 trans-(3R,5S)-atorvastatin Ca (7)을 쥐에서 고지방식이 에 의해 유발된 고지혈증의 치료효과에 대하여 알아보았고, 이러한 연구의 수행을 위해 2010년 1월에 실험을 실시하 였다. 그 결과, 화합물 1과 7의 total cholesterol (TC), high-density lipoprotein-cholesterol (HDL-c), low-density lipoprotein-cholesterol (LDL-c)과 triglyceride (TG)는 각각 93.0±0.5, 43.5±0.8, 40.4±1.4, 45.6±0.9 mg/㎗와 110.0±0.7, 33.3±0.6, 65.8±1.9, 54.8±1.2 mg/㎗를 atherogenic index (AI)와 cardiac risk factor (CRF)는 1.14± 0.05 2.14±0.05와 2.31±0.06, 3.31±0.06을 나타냈으며 aspartate aminotransferase (AST)와 alanine aminotransferase (ALT)는 51.9±4.6, 16.0±2.1 IU/ℓ와 75.8±4.4, 35.1±9.7 IU/ℓ로 두 화합물 모두 고지혈증에 대한 치료효과를 나타내었으나, 화합물 1이 우수한 치료효과가 있는 반면 화합물 7은 치료효과가 낮은 것을 확인하였다. 이러한 결과들로 입체선택적 이성질체 의 합성에 대한 새로운 방법을 제시하고, 향후 시판되고 있는 의약품들의 입체이성질체에 대한 임상적 활용이 가능 할 것으로 사료된다. cis-(3R,5R)-Atorvastatin Ca (1) used for hyperlipidemia have four stereomers. However, It is very difficult to prepare stereoselective stereomers. In this paper, the reduction of 3,5-diketo atorvastatin ester (3) was performed using Me4NHB(OAc)3 in acetic acid as a reductant and showed excellent stereoselectivity in the double reduction of 3,5-diketo atorvastatin ester (3). As a result, reduction of compound 3 by Me4NHB(OAc)3 was purely obtained with cis-(3R,5R)-atorvastatin ester (4) of 1.5% and trans-(3R,5S)-atorvastatin ester (5) of 98.5%. Also, cis-(3R,5R)-atorvastatin Ca (1) and trans-(3R,5S)-atorvastatin Ca (7) were used to determine efficacy in the treatment of liver damage and hyperlipidemia induced by a high-fat diet in rats and to study the performance of the January 2010 experient was conducted. As a result, total cholesterol (TC), high-density lipoprotein-cholesterol (HDL-c), low-density lipoprotein-cholesterol (LDL-c), and triglyceride (TG) levels of compound 1 and 7 groups were 93.0±0.5, 43.5±0.8, 40.4±1.4, 45.6±0.9 mg/㎗ and 110.0±0.7, 33.3±0.6, 65.8±1.9, 54.8±1.2 mg/㎗, respectively. Atherogenic index (AI) and cardiac risk factor (CRF) in compound 1 and 7 were 1.14±0.05, 2.14±0.05 and 2.31±0.06, 3.31±0.06, aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were 51.9±4.6, 16.0±2.1 IU/ℓ and 75.8±4.4, 35.1±9.7 IU/ℓ. Taken together, while compound 1 treat against high-fat diet-induced hyperlipidemia by attenuating hepatic lipid depots and reducing oxidative stress, compound 7 group had a low curative effect on hyperlipidemia induced by a high-fat diet in rats. These findings suggest that new method about synthesis of stereoselective stereomers and indicate that it may consider using in a clinical trial.

1910년대 친일문학의 근대성

최원식(Choi Won-Sik),서영채(토론자) 한림대학교 아시아문화연구소 1998 아시아문화 Vol.- No.14

친환경농산물 RFID 시스템이 신뢰 및 행동의도에 미치는 영향

최원식(Won Sik Choi),김문명(Moon Myoung Kim),이수범(Soo Bum Lee) 한국조리학회 2013 한국조리학회지 Vol.19 No.1

The purpose of this study is to examine the effect relation of the external variables of the RFID for eco-agricultural products, that of the external variables on TAM approachableness and usefulness, that of TAM approachableness on usefulness, that of TAM as approachableness and usefulness on trust and behavior intention, and the effect of trust on the behavior intention. The subjects of the actual analysis are the ordinary consumers aged 20 and over living in Seoul and Gyeong-gi Province and have the experience of purchasing eco-agricultural products. Total 300 copies of questionnaire were distributed for 14 days from September 24, 2012 until October 7, 2012, and total 278(92.7%) copies of survey materials were used for the final statistical analysis data except some found too strong unequal distribution of the response value or the value unknown at present. In the analysis results of this study, by examining the effects of the external variables of the RFID for eco-agricultural products on TAM`s accessibility and usefulness and verifying the causal relationship between TAM`s accessibility and consumers` trust and behavioral intent, this study has a sufficient value as an initial study on the RFID for eco-agricultural products. Thus, the results of this in-depth study show that producers and distributors maintaining and providing with safer eco-agricultural products food directly influence service companies`visible achievements.

절삭가공에서 퍼지알고리즘을 이용한 칩형상 예측

최원식(Won-Sik Choi) 한국산업융합학회 2001 한국산업융합학회 논문집 Vol.4 No.2

In turning, the chip may be produced in the form of continuous chip or discontinuous chip. The continuous chips are dangerous to the operator and difficult to be handled at high speed machining. The signal of AE(Acoustic Emission) is found out to be related to cutting conditions, tool materials, test conditions and tool geometry in turning. In this study, the relationship between AE signal and chip form was experimentally investigated. The experimental results show that the types of chip form are possible to be classified from the AE signal using fuzzy logic.<br/> <br/>