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이감규,정지홍,김전하,강명창,김정석 한국공작기계학회 2004 한국생산제조학회지 Vol.13 No.5
The compressor has one of important roles in refrigeration cycle and it determines refrigeration efficiency and quality. This paper aims to monitor rotary compressors for room air conditioners by using Acoustic Emission(AE) technique. The reliability of rotary compressors has been evaluated through visual inspection on them after long term test. This paper describes methods for acquisition and processing AE raw signal to monitor the state of rotary compressor. A detecting method of abnormal compressor in real time is suggested and special-purpose monitoring system which can be applied to automatic manufacturing line is developed using one-chip microprocessor at low cost.
Lee, Jae keun,Kang, Tae-Wook,Lee, Kam-Gyu,Cho, Min-Chul,Shin, Jin-Hyuk,Kim, Seong-Chan,Koo, Jeong-Hwan,Lee, Jong ho The Korean Society of Mechanical Engineers 2000 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.14 No.11
The ventilation effectiveness is evaluated as a function of air exchange rate and supply / extract locations in a simplified model chamber using a tracer gas technique of CO$_2$ gas injected into a supply duct. Ventilation systems consist of supply and extract fans, a CO$_2$gas generator, a CO$_2$gas analyzer and a test chamber. The ventilation effectiveness is evaluated using a step-down method based on ASTM Standard E741-83. The room mean age of the model chamber is decreased with increasing air exchange rate fanged from 6to 10 air changes per hour. The ventilation effectiveness of the mechanical inlet/natural extract system is better than that of the mechanical extract system.
Synthesis of Na-A zeolite from Jeju Island scoria using fusion/hydrothermal method
Lee, Min-Gyu,Park, Jong-Won,Kam, Sang-Kyu,Lee, Chang-Han Elsevier 2018 CHEMOSPHERE - Vol.207 No.-
<P><B>Abstract</B></P> <P>Na-A zeolite (Z-S1) was synthesized from scoria found on Jeju Island, Korea using the fusion/hydrothermal method. The influences of NaOH/scoria ratio, SiO<SUB>2</SUB>/Al<SUB>2</SUB>O<SUB>3</SUB> molar ratio, and particle sizes on the synthesis of zeolite were studied by analyzing crystals morphology and crystallinity. According to XRD analysis, it was confirmed that the zeolitic materials were synthesized in the range of NaOH/Scoria ratio from 0.6 to 2.4. As the ratio of NaOH/Scoria increased from 0.6 to 1.2, the crystallinity of Z-S1 gradually increased from 8.85% to 57.53%, then became almost constant at 61.80% as the ratio of NaOH/Scoria exceeded 1.8. The particle size of the zeolite crystals tended to decrease with increasing the alkali content of NaOH/Scoria from 0.6 to 1.8. It was possible to synthesize tine crystals having the particle size about 1.0 ㎛ or less at a NaOH/Scoria ratio of 1.8. This study has shown that the fusion/hydrothermal method is a very effective technique for synthesizing Z-S1 from scoria and provides a potential application for obtaining commercial products from natural materials.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The synthetic zeolite was synthesized from scoria using the fusion/hydrothermal method. </LI> <LI> The crystallinity of synthetic zeolite gradually increase with the ratio of NaOH/Scoria. </LI> <LI> The synthetic zeolite crystals tend to decrease in particle size with increasing alkali content. </LI> <LI> The synthetic zeolite crystals have a tine particle size of about 1.0 ㎛ or less. </LI> <LI> The synthetic zeolite synthesized from natural materials provides commercially a potential application. </LI> </UL> </P>
Design and Performance Evaluation of Plasma Air Cleaning Systems for Removing Yellow Sand Dust
Lee, Jae-Keun,Ock, Ju-Ho,Kim, Seong-Chan,Noh, Hyung-Soo,Ahn, Young-Chull,Hwang, Yu-Jin,Lee, Chang-Gun,Kang, Tae-Wook,Lee, Kam-Gyu 한국화학공학회 2004 Korean Journal of Chemical Engineering Vol.21 No.1
Yellow sand dust (Asian dust storms) causes harmful damage indoors and outdoors during the springtime, and the removal of Yellow sand dust has become an issue for suitable indoor conditions. An air cleaner is required to remove Yellow sand dust efficiently to improve indoor air quality, and the removal characteristics of Yellow sand dust should be studied. The size distribution and mass concentration of Yellow sand dust observed in China and Korea are analyzed, and the removal efficiency of a plasma air cleaning system based on the principle of electrostatic precipitation is evaluated by using Yellow sand dust. Mass median diameter of Yellow sand dust sampled in Beijing and Seoul ranges from 7.0 to 8.0㎛ with a mass concentration of 300-1,462㎍/㎥. For a single-pass test, the efficiency of dust removal increases with increasing particle size and decreasing flow rate. The removal efficiency of Yellow sand dust in a plasma air cleaning system at a face velocity of 1.0m/s is higher than 80%. For a multi-pass test in occupied spaces, the operation time required to reduce Yellow sand dust concentration from an initial concentration of 300㎍/㎥ to 150㎍/㎥ is 10 minutes for a test room of 27㎥.
Lee, Min Gyu,Lee, Dong Hwan,Kam, Sang Kyu 한국수산학회 1997 한국수산과학회지 Vol.30 No.6
Biosorbents of nonliving, dried marine brown algae Undaria pinnatifida, Hizikia fusiformis, and Sargassum fulvellum were investigated for their lead biosorption performances. As the amount of biosorbent added was increased, the lead removal by biosorbent materials increased but the lead biosorption capacities decreased. However the lead biosorption capacity by the biosorbent materials increased with increasing initial lead concentration and pH in the range of C_0 10-500㎎/L. Among the biosorbent materials used in this study, the lead biosorption capacity in the solutions with no pH adjustment decreased in the following sequence: U. pinnatifida> H, fusiformis> S. fulvellum. Equilibrium parameters based on Langmuir and Freundlich isotherm were determined. It was found that the lead biosorption by biosorbent materials were expressed by the Langmuir isotherm better than the-Freundlich, isotherm.
Min-Gyu Lee,Sang-Kyu Kam,Chang-Han Lee 대한환경공학회 2021 Environmental Engineering Research Vol.26 No.2
The study focused on the removal of Sr and Cs ions in aqueous solutions by zeolitic materials synthesized from Jeju volcanic rocks using a fusion/hydrothermal method. The synthesis of the zeolitic materials was carried out using the fusion/hydrothermal method to reduce crystallization time. Morphological structures of the zeolitic materials could be confirmed to be the Na-A zeolite structure and crystalline with the chamfered-edged structure. In the adsorption experiment, as the initial concentrations of the Sr and Cs ions increased, it took longer to reach adsorption equilibrium. The adsorption kinetics and isotherms of Sr and Cs ions were predicted well by the pseudo-2nd-order and Langmuir isotherm models, respectively. The maximum adsorption capacities of Sr and Cs ions by the Langmuir isotherm model were 154.8 mg/g and 144.0 mg/g, respectively. The zeolitic materials prepared in this study is considered as an effective adsorbent for removing Sr and Cs ions in aqueous solutions.
2중층 흡착층의 충전방법에 따른 2성분 증기의 흡착특성 변화
이민규 ( Min Gyu Lee ),이송우 ( Song Woo Lee ),감상규 ( Sang Kyu Kam ),이석희 ( Seok Hee Lee ) 한국환경과학회 2012 한국환경과학회지 Vol.21 No.3
This work is to study the variations of adsorption characteristics of binary vapor according to packing system of double-layer bed by fixed bed experiment. Breakthrough curves of single and binary vapor composed of acetone and benzene on single-layer and double-layer adsorption bed composed of activated carbon (AC) and silica-aluminar (SA) were compared. Adsorptions of binary vapor on double-layer bed were influenced by the differences of surface area between adsorbents as well as the polarity difference between adsorbent and adsorbate. The roll-up phenomenon of acetone vapor was happened by replacement with competing adsorption between acetone vapor and benzene vapor on AC bed, but it was not happened on SA bed because acetone vapor and benzene vapor had less difference in affinity with SA bed. The breakthrough times of acetone vapor and benzene vapor on AC/SA double-layer bed were three times and 1.4 times larger respectively than on SA/AC double-layer bed, the differences of breakthrough times were relatively larger than the equilibrium adsorption capacities according to packing system of double-layer bed.
함침농도와 CO2 가스 유입농도에 따른 활성탄의 흡착특성
이동환 ( Dong Hwan Lee ),감상규 ( Sang Kyu Kam ),이송우 ( Song Woo Lee ),이민규 ( Min Gyu Lee ) 한국환경과학회 2010 한국환경과학회지 Vol.19 No.12
The adsorption characteristics of CO2 gas on impregnated activated carbons with MEA (Mono-ethanolamine) and AMP (2-Amino 2-methyl 1-propanol) were studied to improve the adsorption ability of CO2 gas on activated carbon. The equilibrium adsorption capacity of CO2 gas was increased by increment of impregnation concentration up to 40 %, but decreased above 50 %. The adsorption capacity of activated carbon impregnated with AMP was higher than activated carbon impregnated with MEA. The breakthrough was fast according to increment of inlet concentration of CO2 gas.