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김경찬,장대식 영남이공대학 1972 論文集 Vol.1 No.-
Structural members are frequently given profiles widening toward the endes to enable the members to better resist the negative bending moment prevailing at the joints, and design calculations are usually made on the assumption that they are of uniform section, ignoring the potential effect of variation in sectional demensions. This paper considers the extent of such effect and experimentally definess the limit of the size of some such thickening of sections within which such approximate design procedures may result with sufficient engineering practicability.
내부 반사경 543 nm 헬륨 네온 레이저의 편광특성과 단일모드 동작
김경찬,서호성,엄태봉 한국광학회 1998 한국광학회지 Vol.9 No.6
단일모드 출력을 얻기 위해, 횡자장을 걸었을 때와 걸지 않았을 때 내부 반사경 543 nm 헬륨 네온 레이저의 편광특성을 조사하였다. 레이저 출력이 선편광일 때 두 개의 직교하는 편광성분을 측정하였다. 자장을 가하지 않고 레이저 주파수를 이득곡선상에서 주사하였을 경우, 편광 불안정이 크게 발생하였다. 레이저 고유편광에 대하여 35$^{\circ}$방향으로 50 gauss의 횡자장을 가하였을 때 편광 불안정을 억제할 수 있었다. 같은 조건에서 543 nm 헬륨 네온 레이저 주파수를 요오드 분자의 포화 흡수분광선에 안정화시키는데 필요한 880 MHz 대역폭 안에서 안정된 단일모드 동작을 얻을 수 있었다.
김경찬,김영민,정주영,김태권 한국광학회 1998 한국광학회지 Vol.9 No.4
The Measurement of concentration patterns for $C_2$, CH and OH radicals in the premixed propane-air flame could be managed through an image processing technique. This technique was applied to the three kinds of flames on a bunsen burner-mixtures of fuel to be lean, optimum and excessive respectively. The image processing system was complished by treating single wavelength flame images around the eac radical luminescence band, which was obtained by using a set of narrow band pass filters, an image intensifier, CCD and PC. It was possible to observe and predict the reaction zone and the concentration distribution of the radicals, Spatial distribution of each radicals in the raaction zone gave us enough informations to analyze the reaction mechanisms in $C_mH_n$ combustion process. According to this informations, the image of $C_2$ radical exists at front zone, following the images of CH and OH radicals at downstream.
BF<sub>3</sub>LiMA를 단량체로 하는 고체 고분자전해질 합성과 전기화학적 특성
김경찬,류상욱,Kim, Kyung-Chan,Ryu, Sang-Woog 한국전기화학회 2011 한국전기화학회지 Vol.14 No.4
Solid polymer electrolytes using $BF_3LiMA$ as monomer were synthesized by usual one step radical polymerization in THF solvent. The effect of $BF_3LiMA$ concentration on ionic conductivity and electrochemical stability was investigated by AC impedance measurement and linear sweep voltammetry. As a result, the highest ionic conductivity reached $7.71{\times}10^{-6}S\;cm^{-1}$ at $25^{\circ}C$ was obtained in 12.9 wt% of $BF_3LiMA$ content. Further increase or decrease of $BF_3LiMA$ content result to decrease the ionic conductivity due to the brittle matrix properties in former case and the insufficient number of charge carrier in the latter case. Furthermore, since the counter-anion was immobilized in the self-doped solid polymer electrolytes, high electrochemical stability up to 6.0 V was observed even in $60^{\circ}C$.
자기-도핑형 poly(PEGMA-co-BF<sub>3</sub>LiMA) 전해질의 합성과 이온전도도에 대한 PEGMA분자량의 영향
김경찬,류상욱,Kim, Kyung-Chan,Ryu, Sang-Woog 한국전기화학회 2012 한국전기화학회지 Vol.15 No.4
Polymer electrolytes consisted of $BF_3LiMA$ and 300 (PEGMA300) or 1100 (PEGMA1100) g $mol^{-1}$ of PEGMA were prepared and the electrochemical properties were characterized. Interestingly, the AC-impedance measurement shows $1.22{\times}10^{-5}S\;cm^{-1}$ of room temperature ionic conductivity from PEGMA1100 based solid polymer electrolytes while $8.54{\times}10^{-7}S\;cm^{-1}$ was observed in PEGMA300 based liquid polymer electrolytes. The more suitable coordination between lithium ion and ethylene oxide (EO) unit might be the reason of higher ionic conductivity which can be possible in PEGMA1100 based electrolytes since it has 23 EO units in monomer. The lithium ion transference number was found to be 0.6 due to the side reactions between $BF_3$ and lithium metal expecially for longer time but 0.9 was observed within 3000 seconds of measuring time which is strong evidence of a single-ion conductor.
환경기초시설별 지정악취물질 농도로부터 공기희석배수 산정 알고리즘에 관한 연구
김경찬,이춘상,한상우,주흥수,이종민,한진석 한국냄새환경학회 2021 실내환경 및 냄새 학회지 Vol.20 No.1
Environmental fundamental facilities have different odor emission characteristics depending on the type of treatment facilities. To overcome the limitations of the olfactometry method, research needs to be conducted on how to calculate the dilution factor from the individual odor concentrations. The aim of this study was to determine the air dilution factor estimated from manually measured concentration data of individual odor substances (22 specified odor species) in three environmental treatment facilities. In order to calculate the optimum algorism for each environmental fundamental facility, three types of facilities were selected, the concentration of odor substances in the exhaust gas was measured, and the contribution of the overall dilution factor was evaluated. To estimate the dilution factor, four to six algorism were induced and evaluated by correlation analysis between substance concentration and complex odor data. Dilution factors from O municipal water treatment (MWT) and Y livestock wastewater treatment (LWT) facilities showed high level of dilution factors, because concentration levels of hydrogen sulfide and methylmercaptan, which had low odor threshold concentrations, were high. In S food waste treatment (FWT) facility, the aldehyde group strongly influenced dilution the factor (dominant substance: acetaldehyde, i-valeraldhyde and methylmercaptan). In the evaluation of four to six algorism to estimate the dilution factor, the vector algorism (described in the text) was optimum for O MWT and Y LWT, while the algorism using the sum of the top-three dominant substances showed the best outcome for S FWT. In further studies, estimation of the dilution factor from simultaneously monitored data by odor sensors will be developed and integrated with the results in this study.