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린 6시그마 분석을 통한 도면 주기 품질 향상 방안 연구
전용구 ( Jeon Yong Gu ),허형조 ( Huh Hyoung Jo ),이성배 ( Lee Seong Bae ),박훈혁 ( Park Hun Hyuk ),안병국 ( An Byung Guk ) 한국품질경영학회 2020 품질경영학회지 Vol.48 No.3
Purpose: The purpose of this study was to find useful solutions by analyzing causes and results about defects on mechanical drawing notes and provide an automated tool with solutions to mechanical engineers. Methods: The collected data for defects on mechanical drawing notes were from ongoing development and mass production projects. Various measurement methods were used based on the Lean 6 Sigma analysis such as Process analysis, C&E diagram and some statistical analysis. Results: The results of this study are as follows; The results of the Lean 6 Sigma analysis, the validity of the selected indicators for improving drawing notes quality was verified through the verification of cause variables. The strategy established to improve the mechanical drawing notes was reflected as an automated program, and the defects were within a manageable range and achieved target Sigma level. Conclusion: Through the application of the “Mechanical drawing notes automation tool”, it is expected to resolve the “Voice of Customer, VOC” and “Voice of Business, VOB”
MO 理論에 依한 反應性의 決定 (第14報). Diels-Alder 反應의 配向性에 미치는 酸觸媒의 效果
이익춘,류근배,전용구,Ikchoon Lee,Keun Bae Rhyu,Jeon, Yong Gu 대한화학회 1979 대한화학회지 Vol.23 No.5
非對稱으로 置環된 diene과 dienophile 間의 反應에서 配向性에 미치는 산촉매의 효과를 豫期하기 위해서 루이스酸과 錯物을 形成한 dienophile의 理論的모델에 FMO 理論을 적용하여CNDO/2 방법으로 고찰하였다. 電子的性質이 類似한 치환기로 치환된 diene, dienophile의 반응(즉, 電子不足 diene과 電子不足 dienophile의 반응)에서 일어나는 半極性 고리化반응을 제외한 주어진 대부분의 반응에 대해서, CNDO/2방법이 실험적인 配向性과 一致하는 좋은 결과를 주었다. 또한 二次軌道相互作用이 非對稱으로 치환된 diene과 dienophile의 Diels-Alder 반응의 배향성에 중요한 역할을 했다는 사실을 보여주었다. Anh의 방법이 다른 방법보다 수식적으로 간단할지라도, 非對稱전이상태를 강조한 Anh의 방법이 配向性 결정에 좋은 결과를 주었다. In order to predict the effect of Lewis acid catalysis on the regioselectivity of the Diels-Alder reactions between unsymmetrically substituted dienes and dienophiles, the frontier orbital theory applied to the theoretical model of the Lewis acid complexed dienophile was studied by means of CNDO/2 MO. In the majority of reactions, CNDO/2 calculations gave good results in accordance with experimental orientation. Also, it was shown that the secondary orbital interaction played an important role in the regioselectivity of the Diels-Alder reaction between unsymmetrically substituted dienes and dienophiles. Although ANH's treatment is mathematically simpler than other methods, ANH's method which laid emphasis on dissymmetrical transition state gave good results on decision of regioselectivity.
强酸性 溶液中에서 Cinnamonitrile의 加水分解 反應메카니즘
권기성,성낙도,김태린,전용구,Ki-Sung Kwon,Nack-Do Sung,Tae-Rin Kim,Jeon, Yong Gu 대한화학회 1984 대한화학회지 Vol.28 No.6
Cinnamonitrile의 산-가수분해 반응속도상수를 25$^{\circ}$C, HClO$_4$ 1 ~ 5M의 센산성 용액속에서 UV분광법으로 측정하고 Bunnett관계식에 적용하여 ${\omega}$ = 9.8, ${\omega}^*$ = 0.42 및 ${\phi}$=1.6등의 hydration parameter를 구하였다. 이는 질소원자에 양성자화가 이루어진 짝산에 대하여 속도결정단계에서 친핵체로 물분자가 첨가된 다음에 양성자 전달체로 작용한다는 것을 시사한다. Cinnamonitrile 분자의 궤도함수를 CNDO/2방법으로 계산한 바, 형태이성체의 안정도는 (E)-planar>(Z)-planar이였으며 음하전의 크기는 $C_8({\beta}){\ll}N$이였고 전이상태에서 물분자는 짝산의 양하전이 큰 $C_7({\alpha}$)원자에 대하여 ${\sigma}$접근함을 알았다. 이상의 결과로 부터, 센산성속에서 cinnamonitrile의 가수분해반응은 특정 산-촉매작용을 수반하는 A-2형의 산-가수분해 반응메카니즘에 의하여 진행됨을 알았다. Rate constants for the hydrolysis of cinnamonitrile in the concentration range of 1 ∼ 5M of perchloric acid at 25$^{\circ}$C have been determined by UV spectrophotometry and from the Bunnett equations, hydration parameters (${\omega}$ = 9.8, ${\omega}^*$ = 0.42 & ${\phi}$=1.6) were obtained. CNDO/2 MO calculations were performed to determine relative stability, net charges, and overlap population of various conformational isomers. The results show that the (E)-planar is more stable than the (Z)-planar and protonation is favored on the nitrogen atom. On the basis of above findings, the acid hydrolysis is initiated by the protonation of the nitrogen atom of cinnamonitrile and then water molecule acting as nucleophile and as a proton transfer agent in the rate determining step. In the transition state of the acid hydrolysis, nucleophilic addition of water molecule occurs by sigma approach to the positively charged $C_7({\alpha}$) atom of the conjugate acid. As the results, we may conclude that the hydrolysis of cinnamonitrile in the strong acidic media proceeds through the A-2 type mechanism.