실험계획법을 이용한 연삭가공물의 표면거칠기 분석

지용주,이상진,박후명,곽재섭,하만경 한국공작기계학회 2004 한국공작기계학회 추계학술대회논문집 Vol.2004 No.-

A measure for good products manufactured by grinding process is the surface roughness that is affected by a lot of operating parameters such as types of abrasive, grain size, bond material, wheel speed, table speed, depth of cut, hardness of workpiece and stiffness of grinding machine. In this study, an application of the design of experiments was tried for evaluating the effect of operating parameters on the surface roughness. The workpiece was a high speed tool steel(SKH5I) and the surface grinding was conducted. In order to obtain the best surface roughness within constraints of the working range, the optimal grinding conditions were selected. The usefulness of this method was evaluated by the statistical strategy.

실험계획법을 이용한 연삭가공물의 형상오차 분석

지용주,곽재섭,하만경 한국공작기계학회 2004 한국생산제조학회지 Vol.13 No.4

Various controllable parameters of an experiment have influence on grinding process. In order to get good products with a high quality, these parameters should be considered whether each parameter has relations to the quality. This paper describes the use of the design of experiments to minimize geometric error in surface grinding. Controllable parameters for the design of experiments were selected as spindle speed, table speed, depth of cut and grain size. From the experimental results, a degree of influence between these parameters and the geometric error was evaluated. An optimal set of grinding conditions was obtained by means of analysis of variance(ANOVA).

연삭력을 이용한 공작물의 형상오차 예측

지용주,곽재섭,하만경 한국공작기계학회 2004 한국생산제조학회지 Vol.13 No.2

Because a generated heat h g grinding operation makes a serious deformation on a ground surface as a convex form, a real depth of cut in deformed zone has larger than an ideal depth of cut. Consequently, the ground surface has a geometric error as a concave form after cooling the workpiece. In this study, the force and the geometric error of surface grinding were examined. From evaluating magnitude and mode of the geometric error according to grinding conditions, an optimal grinding condition was proposed to minimize the geometric error. In addition, the relationship between the geometric error and the grinding force was found out. Due to least square regression, it was able to predict the geometric error by using the grinding force.

다구찌기법에 의한 형상오차 평가 및 최적화

지용주,곽재섭,하만경 한국공작기계학회 2004 한국공작기계학회 춘계학술대회논문집 Vol.2004 No.-

This paper deals with the evaluation of geometric error and the optimization of process parameters in surface grinding. Taguchi method which is one of the design of experiments has been introduced in achieving the aims. The process parameters were the grain size, the wheel speed, the depth of cut and the table speed. The effect of the process parameters on the geometric error was examined and an optimal set of the parameters was selected to minimize the geometric error within the controllable range of the used grinding machine. The reliablity of the results was evaluated by the ANOVA.

한·중 근대시에 나타난 도시/고향 표상 비교 연구 - 자기-정체화, 부성, 모성의 가족적 지향을 중심으로

주만만(Zhu Man-man),정민구(Jeong Min-gu),김민지(Kim Min-ji),김동근(Kim Dong-geun) 전남대학교 한국어문학연구소 2020 전남대학교 한국어문학연구소 학술지 어문논총 Vol.- No.36

한·중 근대시인 오장환과 애청의 시에는 도시/고향 표상이 빈번하게 나타난다. 기존 연구에서는 두 시인의 시에 나타난 도시/고향 표상을 근대성/전근대성, 문명/전통 등의 대립적 의미 체계를 통해 논의하는 경향을 보였다. 본 논문에서는 두 시인의 시에서 나타난 도시/고향 표상이 자기-정체화, 부성, 모성이라는 삼항적 관계 속에서 중층적으로 형상화되고 있다고 보았다. 오장환은 근대 도시를 방랑하면서 ‘실업자’나 ‘병자’로 자신을 정체화하며, 애청은 프랑스의 대도시를 거닐면서 ‘나그네’, ‘보헤미안’으로 자신을 정체화한다. 또한 두 시인은 부성을 통해 도시와 이향(離鄕)에 대한 감각을 환기시키고, 모성을 통해 고향과 귀향(歸鄕)에 대한 감각을 환기시킨다. 이러한 자기-정체화와 도시/고향의 형상화 과정은 부성/모성의 투사를 통한 중층적 관계망 속에서 이루어지는 바, 본 논문은 이를 가족적 지향으로 볼 수 있음을 시론(試論)하고자 하였다. In the poems of Oh Jang-hwan and Ai Qing, the modern poets of Korea and China, urban/hometown representations are frequent. Previous studies have shown a tendency to discuss urban/hometown representations in the poems of the two poets through confrontational semantic systems such as modernity/pre-modernity and civilization/tradition. In this paper, it was noted that the urban/hometown representations shown in the poems of the two poets are being modeled in a trichotomous relationship of self-identification, fatherhood, and motherhood. While wandering through modern cities, Oh Jang-hwan identifies himself as a “failure” or a “sick man,” and Ai Qing identifies himself as a “traveler” and “bohemian” while he strolls through the French metropolis. The two poets also evoke a sense of city and homecoming through their motherhood. This process of self-identification and urban/hometown shaping takes place in a multi-layered network of relationships through the projection of fatherhood/motherhood, and this paper intends to demonstrate that this could be viewed as family orientation.

1920∼30년대 한 · 중 근대시 ‘고향’의 재현 양상 연구

주만만(Zhu, Man-man) 전남대학교 한국어문학연구소 2017 전남대학교 한국어문학연구소 학술지 어문논총 Vol.- No.30

1920년대 이후 한 · 중 근대시는 서구 문예사조를 수용하는 과정 속에서 근대적 심상공간으로의 ‘고향’에 대한 발견과 상실, 그리고 재창조를 이루었다. 한 · 중 양국에서 자국 근대시에 나타난 고향 이미지나 고향 의미에 관한 연구는 풍부한 성과가 이루어져 왔지만, 비교문학적 차원에서 양국 근대시 고향 재현 양상을 고찰하는 연구는 미비한 편이다. ‘고향’이란 단어 자체가 ‘상실’의 의미를 함축하고 있었으며, 근대 한 · 중 양국의 식민지 · 반식민지적 상황과 근대화 과정으로 인하여 이런 ‘상실감’이 더 심화되었다고 할 수 있다. 이로써 고향은 ‘과거’, ‘상실’, ‘부재’, ‘기억’등이라는 여러 가지 은유로 파생될 수 있는 것이다. ‘고향=과거’와 같은 시간적 재현 양상뿐만 아니라 ‘고향=향토(자연)’, ‘고향=전근대(전통)’ 등 공간적 재현 양상도 나타난다. 이러한 고향 재현 양상들을 통해 근대 지식인들의 고향에 대한 복잡한 감정과 모순적 태도도 쉽게 엿볼 수 있다. 본고는 정지용과 오장환, 중국 시인 대망서(戴望舒)와 애청(艾靑)의 시 작품들을 주요 연구대상으로 하여 1920∼30년대 한 · 중 근대시에 나타난 고향 재현 양상을 고찰하고자 한다. 시인 생의 공간 이동을 보면, 순차적으로 모태, 농촌, 도시, 해외 등으로 나눌 수 있으며, 각 단계에 처하는 시인들의 고향 재현 양상도 다소 다를 것이다. 그중에서 필자는 가장 대표성을 띤 세 가지 고향 재현 양상, 즉 ‘어머니로서의 고향’, ‘유토피아로서의 고향’, ‘조국으로서의 고향’을 살펴보고자 한다. 어머니를 떠난 시인들은 모태귀소본능으로 항상 어머니에 대한 사랑과 그리움을 향수로 간주함으로써 어머니와 고향을 동일시하기 한다. 또한 도시 생활에 지친 시인들은 태어난 농촌을 유토피아적 이상향으로 미화함으로써 정신적 안식처를 얻는다. 마지막으로 식민지 · 반식민지 시기 빼앗긴 조국땅으로 인한 상실감을 느낀 시인들은 흔히 고향을 조국의 의미로 확대시키고 향수를 애국 정감으로 승화시키기도 한다. 또한 이 세 가지 고향 재현 양상들은 모두 극대화된 고향 상실성과 부재성을 잘 반영하고 있다. 구체적으로 말하면, ‘어머니’는 곁에 없는 존재이고, ‘유토피아’는 실재로 존재하지 않는 공간이고, ‘조국’은 이미 잃어버린 땅이다. 이는 고향을 재현하기 위해 제시된 사물들의 동질성도 잘 드러내고 있다. 고향 재현에 대한 고찰을 통해 우리는 한 · 중 근대시에 나타난 향토성, 민족성 등 여러 특성뿐만 아니라 전통과 근대, 개인과 국가 사이에 헤매는 근대 지식인들의 딜레마적 내면 세계를 탐색할 수 있을 것이다.

Copolymerization of Ethylene and Norbornene via Polymethylene Bridged Dinuclear Constrained Geometry Catalysts

Zhu, Yin-Bang,Jeong, Eung-Yeong,Lee, Bae-Wook,Kim, Bong-Shik,Noh, Seok-Kyun,Lyoo, Won-Seok,Lee, Dong-Ho,Kim, Yong-Man The Polymer Society of Korea 2007 Macromolecular Research Vol.15 No.5

The dinuclear half-sandwich CGCs (constrained geometry catalyst) with a polymethylene bridge, $[Ti({\eta}^5 : {\eta}^1-indenyl)SiMe_2NCMe_3]_2(CH_2)_n]$[n = 6 (1) and 12 (2)], have been employed in the copolymerization of ethylene and norbornene (NBE). To compare the mononuclear metallocene catalysts; $Ti({\eta}^5 : {\eta}^1-2-hexylindenyl)SiMe_2NCMe_3$ (3), $(Cp^* SiMe_2NCMe_3)$Ti (Dow CGC) (4) and ansa-$Et(Ind)_2ZrCI_2$ (5), were also studied for the copolymerization of ethylene and NBE. It was found that the activity increased in the order: 1 < 2 < 3 < 5 < 4, indicating that the presence of the bridge between two the CGC units contributed to depressing the polymerization activity of the CGCs. This result strongly suggests that the implication of steric disturbance due to the presence of the bridge may playa significant role in slowing the activity. Dinuclear CGCs have been found to be very efficient for the incorporation of NBE onto the polyethylene backbone. The NBE contents in the copolymers formed ranged from 10 to 42%, depending on the polymerization conditions. Strong chemical shifts were observed at ${\delta}$42.0 and 47.8 of the isotactic alternating NBE sequences, NENEN, in the copolymers with high NBE contents. In addition, a resonance at 47.1 ppm for the sequences of the isolated NBE, EENEE, was observed in the $^{13}C-NMR$ spectra of the copolymers with low NBE contents. The absence of signals for isotactic dyad at 48.1 and 49.1 ppm illustrated there were no isotactic or microblock (NBE-NBE) sequences in the copolymers. This result indicated that the dinuclear CGCs were effective for making randomly distributed ethylene-NBE copolymers.

감자흑각병(Potato Blackleg Disease) 방제를 위한 살균제 선발

Zhu Yong-Zhe,박덕환(Duck-Hwan Park),박동식(Dong-Sik Park),유용만(Yong-Man Yu),김성문(Songmun Kim),임춘근(Chun-Keum Lim),허장현(Jang-Hyun Hur) 한국농약과학회 2003 농약과학회지 Vol.7 No.2

Enantioseparation and Determination of Sibutramine in Pharmaceutical Formulations by Capillary Electrophoresis

Zhu, Hongmei,Wu, Enqi,Chen, Jianbo,Men, Chuvan,Jang, Yu-Seon,Kang, Won-Ku,Choi, Jung-Kap,Lee, Won-Jae,Kang, Jong-Seong Korean Chemical Society 2010 Bulletin of the Korean Chemical Society Vol.31 No.6

Sibutramine enantiomers were separated successfully by capillary zone electrophoresis using substituted cyclodextrins as chiral selectors. The effects of cyclodextrin concentration, pH, voltage, buffer type, and electrolyte concentration on the migration time and resolution of enantiomers were examined. Separation of sibutramine enantiomers on an unmodified fused silica capillary (total length, 54 cm; effective length, 45 cm) was achieved using a mixed buffer of 20 mM phosphate/10 mM citrate containing either 5 mM methyl-${\beta}$-cyclodextrin (pH 4.3) or 5 mM carboxymethyl-${\beta}$-cyclodextrin (pH 6.5). Samples were injected with a pressure of 50 mbar for 5 s and were detected at a wavelength of 223 nm. The established method showed good precision and accuracy, with intra- and inter-day variations of less than 2.9 and 4.7%, respectively, and recoveries of 95.7 - 103.8%. The stability constants of (R)- and (S)-sibutramine demonstrated that the resolution of sibutramine enantiomers was attributable primarily to the difference in stability constants. When this optimized method was applied to the determination of sibutramine enantiomers in commercial drug formulations, it proved to be economical and convenient, affording sufficient accuracy, precision, and reproducibility as well as sensitivity and selectivity.

Enantioseparation and Determination of Sibutramine in Pharmaceutical Formulations by Capillary Electrophoresis

Hongmei Zhu,Enqi Wu,Jianbo Chen,Chuvan Men,장유선,Wonku Kang,Jung Kap Choi,이원재,강종성 대한화학회 2010 Bulletin of the Korean Chemical Society Vol.31 No.6

Sibutramine enantiomers were separated successfully by capillary zone electrophoresis using substituted cyclodextrins as chiral selectors. The effects of cyclodextrin concentration, pH, voltage, buffer type, and electrolyte concentration on the migration time and resolution of enantiomers were examined. Separation of sibutramine enantiomers on an unmodified fused silica capillary (total length, 54 cm; effective length, 45 cm) was achieved using a mixed buffer of 20 mM phosphate/10 mM citrate containing either 5 mM methyl-β-cyclodextrin (pH 4.3) or 5 mM carboxymethyl-β-cyclodextrin (pH 6.5). Samples were injected with a pressure of 50 mbar for 5 s and were detected at a wavelength of 223 nm. The established method showed good precision and accuracy, with intra- and inter-day variations of less than 2.9 and 4.7%, respectively, and recoveries of 95.7 - 103.8%. The stability constants of (R)- and (S)-sibutramine demonstrated that the resolution of sibutramine enantiomers was attributable primarily to the difference in stability constants. When this optimized method was applied to the determination of sibutramine enantiomers in commercial drug formulations, it proved to be economical and convenient, affording sufficient accuracy, precision, and reproducibility as well as sensitivity and selectivity.