층층나무 잎의 Phenol성 성분 (I)

이동호,이승호,정시련,노재섭,이경순,Lee, Dong-Ho,Lee, Seung-Ho,Chung, See-Ryun,Ro, Jai-Seup,Lee, Kyong-Soon 한국생약학회 1995 생약학회지 Vol.26 No.4

Twelve phenolic components were isolated from the aqueous acetone extract of the leaf of Cornus controversa H. (Cornaceae). On the basis of chemical and spectroscopic evidence, the structures of these components were established as gallic acid, $1-O-galloyl-{\beta}-{_D}-glucose$, $1,6-di-O-galloyl-{\beta}-{_D}-glucose$, $1,2,3-tri-O-galloyl-{\beta}-{_D}-glucose$, $1,2,6-tri-O-galloyl-{\beta}-{_D}-glucose$, 3,4,6-tri-O-galloyl ${_D}-glucose$, eugeniin, gemine D, quercetin, quercitrin, hyperoside and rutin.

트리실록산 및 펜타메틸렌 간격자를 도입한 CpIndZrCl2 실리카 담지촉매에 의한 에틸렌 중합

이동호,윤근병 ( Dong Ho Lee,Keun Byoung Yoon ) 한국화학공학회 1996 화학공학의이론과응용 Vol.2 No.2

Linear Low Density Polyethylene Preparation by Titanium-Based Ziegler-Natta Catalysts

이동호,민경은,김차웅,Dong-Ho Lee,Kyung-Eun Min,Cha-Ung Kim Korean Chemical Society 1987 대한화학회지 Vol.31 No.1

선형저밀도폴리에틸렌(LLDPE)의 제조를 위해 여러가지 티탄알콕시드-알킬알루미늄 화합물을 촉매로 하여 에틸렌과 1-부텐을 슬러리 상태로 공중합하였다. 이때 촉매성분의 종류 및 농도, 숙성시간, 중합시간과 중합온도 등이 촉매활성과 공중합체 조성에 미치는 영향을 연구하였다. 그리고 공중합체의 성질과 1-부텐 함량과의 관계를 조사하였다. 그 결과 티탄사노르말부톡시드-염화디에틸알류미늄의 촉매를 사용하였을 때 가장 큰 촉매활성, 보다 많은 1-부텐 함량 및 가장 작은 가용성 부분의 LLDPE를 얻을 수 있었다. 얻은 공중합체의 밀도, 유리전이온도, 녹는점 및 녹음열 등은 1-부텐의 함량이 증가함에 따라 감소하였다. For the preparation of linear low density polyethylene (LLDPE), the copolymerization of ethylene and 1-butene was carried out with various catalysts of titanium alkoxidealkylaluminum compound in slurry phase. The effects of catalyst components, aging time, concentration of catalyst components, polymerization time and temperature on the catalytic activity and copolymer composition were examined. The properties of copolymer obtained were also considered with the correlation to the 1-butene contents. It has been found that the titanium tetra-n-butoxide-diethylaluminum chloride catalyst system was the most suitable for the production of LLDPE with higher catalytic activity, more 1-butene content and less soluble parts. The density, glass transition temperature, melting point and heat of fusion of copolymer were decreased with increasing 1-butene contents.

염화코발트(Ⅱ)에 의한 비닐단위체의 중합

이동호,안태완,Lee Dong-ho,Ahn Tae-oan 대한화학회 1975 대한화학회지 Vol.19 No.1

The polymerization of methyl methacrylate initiated by cobalt(II) chloride in tetrahydrofuran has been studied. The conversion was increased liearly with polymerization time at initial stage of 6${\sim}$7% conversion and then the rate of polymerization was slightly reduced, and after that the autoacceleration was observed. The rate of polymerization was increased with the concentration of cobalt(Ⅱ) chloride, but at the concentration of cobalt(II) chloride higher than $3.4{\times}10^{-4}$ mole/l the rate of polymerization was decreased. The rate of polymerization was dependent on the 1.38 power of the concentration of methyl methacrylate. The effect of the radical inhibitor DPPH was observed and the inhibition time was increased with the concentration of DPPH. The apparent overall activation energy was calculated to be 13.2 kcal/mole. In the copolymerization of methyl methacrylate ($M_1$) and styrene ($M_2$), the monomer reactivity ratio was found to be $r_1$ = 2.35, $r_2$ = 0.78. From the above results. the initiation mechanism of polymerization was discussed and it was considered that the polymerization proceeds mainly via diradical mechaism. Co$Cl_2$-THF-MMA계에 대한 중합반응을 조사한 결과 다음과 같은 사실을 알았다. 즉 중합시간에 따른 중합변화율이 6${\sim}$7% 미만의 초기에는 직선적인 관계가 있으나 차차 중합속도가 감소했다가 그 후에는 라디칼중합의 경우와 같이 자동가속화현상을 볼 수 있었다. 개시물인 염화 코발트(II)의 농도가 증가하면 중합속도가 증가했다가 약 $3.4{\times}10^{-4}$mole/l 이상이 되면 반대로 중합속도는 감소하였다. 그리고 단위체인 MMA의 농도에 따라 중합속도는 1.38의 반응차수를 가지고 증가하였다. 라디칼중합에 대한 억제물인 DPPH를 첨가하면 억제기간이 생기고 이 억제기간은 DPPH의 농도에 따라 증가하였다. 이 중합계에 대한 겉보기 총 활성화 에너지는 13.2kcal/moe임을 알았다. MMA($M_1$)과 styrene($M_2$)의 공중합체에 대한 단위체 반응성비는 $r_1$=2.35, $r_2$=0.78이었다. 그리고 이러한 실험결과에서 이 계에 의한 중합개시 메카니즘을 논의하여 디라디칼에 의한 중합이 우세하게 일어난다고 생각되었다.

크라우드소싱 드론 영상의 기하학적 품질 자동 검증

이동호,최경아,Dongho Lee,Kyoungah Choi 대한원격탐사학회 2023 大韓遠隔探査學會誌 Vol.39 No.5

The utilization of crowdsourced spatial data has been actively researched; however, issues stemming from the uncertainty of data quality have been raised. In particular, when low-quality data is mixed into drone imagery datasets, it can degrade the quality of spatial information output. In order to address these problems, the study presents a methodology for automatically validating the geometric quality of crowdsourced imagery. Key quality factors such as spatial resolution, resolution variation, matching point reprojection error, and bundle adjustment results are utilized. To classify imagery suitable for spatial information generation, training and validation datasets are constructed, and machine learning is conducted using a radial basis function (RBF)-based support vector machine (SVM) model. The trained SVM model achieved a classification accuracy of 99.1%. To evaluate the effectiveness of the quality validation model, imagery sets before and after applying the model to drone imagery not used in training and validation are compared by generating orthoimages. The results confirm that the application of the quality validation model reduces various distortions that can be included in orthoimages and enhances object identifiability. The proposed quality validation methodology is expected to increase the utility of crowdsourced data in spatial information generation by automatically selecting high-quality data from the multitude of crowdsourced data with varying qualities.

항공기 엔진산업의 특성과 현황

이동호,Lee, Dong-Ho 한국항공우주산업진흥협회 1996 航空宇宙 Vol.42 No.-

압전작동기로 구동 되는 보울 파트 피더의 모드 해석과 이송 속도 제어

이동호,최승복,김재환,Lee, Dong-Ho,Choe, Seung-Bok,Kim, Jae-Hwan 대한기계학회 2000 大韓機械學會論文集A Vol.24 No.4

This paper presents modal analysis and mean conveying velocity (M.C.V.) control of bowl parts feeder activated by piezoactuators. Bowl parts feeders are being widely used in many industry fields for automatic assembly line. In general, the electromagnet has been and being used as exciting actuator of these vibratory bowl feeders. However, because of complexity of its mechanism and limited capability of the electromagnet actuator, there exist various impending problems such as severe noise, nonlinear motion of parts, passive characteristics and so forth. As one of solutions for these problems, piezoelectric actuators as new actuating technology have been proposed recently to excite the bowl parts feeder. In this paper, modal analysis of the proposed model has been performed to examine the modal characteristics of the model by using commercial FEM software and modeling with respects to MCV is constructed. Finally, MCV of the parts is to be controlled to track the desired one with PID controller.

컬러화보-항공기 발달사

이동호,Lee, Dong-Ho 한국과학기술단체총연합회 1994 과학과 기술 Vol.27 No.3

WHO 체제하(體制下)의 분쟁해결절차(紛爭解決節次)

이동호,Lee, Dong-Ho 한국중재학회 1994 중재연구 Vol.4 No.-

환형 캐스케이드 내 고정된 터빈 블레이드 및 슈라우드에서의 열/물질전달 특성 (II) - 끝단 필 슈라우드 -

이동호,조형희,Lee Dong-Ho,Cho Hyung Hee 대한기계학회 2005 大韓機械學會論文集B Vol.29 No.4

Experiments were conducted in a low speed stationary annular cascade to investigate local heat transfer characteristics on the tip and shroud and the effect of inlet Reynolds number on the tip and shroud heat transfer. Detailed mass transfer coefficients on the blade tip and the shroud were obtained using a naphthalene sublimation technique. The turbine test section has a single stage composed of sixteen guide vanes and blades. The chord length and the height of the tested blade are 150 mm and about 125 mm, respectively. The blade has flat tip geometry and the mean tip clearance is about $2.5{\%}$of the blade chord. The inlet flow Reynolds number based on chord length and incoming flow velocity is changed from $1.0{\times}10^{5}\;to\;2.3{\times}10^{5}.$ to investigate the effect of Reynolds number. Flow reattachment after the recirculation near the pressure side edge dominates the heat transfer on the tip surface. Shroud surface has very intricate heat/mass transfer distributions due to complex flow patterns such as acceleration, relaminarization, transition to turbulent flow and tip leakage vortex. Heat/mass transfer coefficient on the blade tip is about 1.7 times as high as that on the shroud or blade surface. Overall averaged heat/mass transfer coefficients on the tip and shroud are proportional to $Re_{c}^{0.65}\;and\;Re_{c}^{0.71},$ respectively.