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마이크로 엔드밀을 이용한 측면가공에서의 공구변형에 의한 가공오차 보상
전두성,서태일,윤길상,장호수 한국공작기계학회 2007 한국공작기계학회 추계학술대회논문집 Vol.2007 No.-
This paper presents an integrated machining error compensation without measuring cutting force in micro end-mill. To compensate machining error, we consider new tool path. In order to determine the compensated tool path, two machining error parameters are defined and modeled using the SEM images. Experiments are carried out to validate the approaches proposed in this paper. In result, we identify the proposed methods are effective to compensate for machining errors.
Intramolecular Proton Transfers of 2-hydroxy-4,5-naphthotropone
Du-Jeon Jang Korean Chemical Society 1991 Bulletin of the Korean Chemical Society Vol.12 No.4
The intramolecular proton transfers of 2-hydroxy-4,5-naphthotropone in room temperature solutions are studied using static and time-resolved absorption and emission spectroscopy. Dual normal and tautomer fluorescence is observed in ethanol solution, while only the tautomer fluorescence is observed in cyclohexane solution. The fluorescence lifetimes and quantum yields in ethanol and cyclohexane solutions indicate that in hydrocarbon solvents, rapid intersystem crossing competes with proton transfer in the first excited singlet state. Transient absorption spectra and kinetics indicate that proton transfer also undergoes in the first triplet state with a transfer time of ∼ 3 ns. No transient absorption from the tautomer ground state indicates a rapid back proton transfer in the ground state.
Jang, Du-Jeon,Lee, SunBae Korean Society of Photoscience 1995 Journal of Photosciences Vol.2 No.1
Picosecond time-resolved and static protein fluorescence spectra and absorption spectra of octopus rhodopsin, a photorecepting protein, are measured and compared with those of bacteriorhodopsin, a photon-induced proton pumping protein, to understand the protein conformations and functions of octopus rhodopsin and its deprotonated photocycle intermediate. The bluer and weaker absorption of retinal indicates that octopus rhodopsin is better in thermal noise suppression but less efficient in light harvesting than bacteriorhodopsin. The protein fluorescence of octopus rhodopsin shows the characteristic of Trp only and the uantum efficiency and lifetime variations may result primarily from variations in the coupling strength with the retinal. The stronger intensity by four times and larger red shift by 12 nm of fluorescence suggest that octopus rhodopsin has more open and looser structure compared with bacteriorhodopsin. Fluorescence decay profiles reveal two decay components of 300 ps (60%) and 2 ns (40%). The deprotonation of protonated Schiff's base increases the shorter decay time to 500 ps and enhances the fluorescence intensity by 20%. The fluorescence and its decay time from Trp residues near retinal are influenced more by the deprotonation. The increase of fluorescence intimates that protein structure becomes loosened and relaxed further by the deprotonation of protonated Schiff's base. The driving force of sequential changes initiated by absorption of a photon is too exhausted after the deprotonation to return the intermediate to the ground state of the begun rhodopsin form.
Photoionization of N,N,N',N'-Tetramethyl-p-phenylenediamine in Polar Solvents
Min Yeong Lee,Du Jeon Jang,Minyung Lee,Du-Jeon Jang,Dongho Kim,Sun Sook Lee,Bong Hyun Boo Korean Chemical Society 1991 Bulletin of the Korean Chemical Society Vol.12 No.4
The photoinduced electron transfer reactions of N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD) in various polar solvents were studied by measuring time-resolved fluorescence. The temperature dependence on the fluorescence decay rate in acetonitrile, methanol, ethanol and buthanol was carried out to obtain the activation energy and Arrehnius factor for the photoinduced electron transfer reaction. It was found that as the dielectric constant of the solvent increases, the activation energy and the reaction rate increase. This implys that the Arrehnius factor is important in controlling the photoinduced electron transfer reaction rate. In water, TMPD exists in three forms (cationic, protonated and neutral forms) due to the high dielectric constant and strong proton donating power of water. The photoinduced electron transfer reaction was found to be very fast (< 50 ps) and also the long liverd component in the fluorescence decay profile attributable to the photoexcited protonated form of TMPD was observed. Probably, the reaction pathway and the reaction coordinate seem to be different depending on the solvents studied here.
마이크로 엔드밀을 이용한 측면가공에서의 공구변형에 의한 가공오차 보상
전두성(Du-Seong Jeon),서태일(Tae-il Seo),윤길상(Gil-Sang Yoon),장호수(Ho-Su Jang) 한국생산제조학회 2007 한국생산제조시스템학회 학술발표대회 논문집 Vol.2007 No.10
This paper presents an integrated machining error compensation without measuring cutting force in micro end-mill. To compensate machining error, we consider new tool path. In order to determine the compensated tool path, two machining error parameters are defined and modeled using the SEM images. Experiments are carried out to validate the approaches proposed in this paper. In result, we identify the proposed methods are effective to compensate for machining errors.
혈관재건술로 치료한 완전 신동맥 폐색에 의한 신혈관성 고혈압 치험
전두수 ( Jeon Du Su ),승기배 ( Seung Gi Bae ),이길환 ( Lee Gil Hwan ),박준철 ( Park Jun Cheol ),채장성 ( Chae Jang Seong ),방병기 ( Bang Byeong Gi ),최규보 ( Choe Gyu Bo ),고용복 ( Go Yong Bog ) 대한내과학회 1992 대한내과학회지 Vol.42 No.3
Renovascular hypertension is oine of the secondary hypertension, which can be cured by surgical treatment. With the marked advances in the technique of vascular surgery, artery reconstruction is prefered to nephrectomy. Even the patients with complete occlusion of the renal artery discovered on arteriographic investigation can undergo renal artery revascularization with successful restoration of renal blood flow with control of hypertension. We report a case of renovascular hypertension with complete left renal artery obstruction in a 49 year ole man, corrected by an autogenous saphenous vein aortorenal bypass grafrt.