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Microfluidic dual loops reactor for conducting a multistep reaction

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Frontiers of Chemical Science and Engineering 2018年第2期12卷 239-246页

作者： Si Hyung Jin Jae-Hoon Jung Seong-Geun Jeong Jongmin Kim Tae Jung Park chang-soo lee Department of Chemical Engineering Chungnam National University Daejeon 34134 Korea Lotte Chemical R&D Center Daejeon 34110 Korea Department of Chemistry Chung-Ang University Seoul 06974 Korea

Precise control of each individual reaction that constitutes a multistep reaction must be performed to obtain the desired reaction product efficiently. In this work, we present a microfluidic dual loops reactor that enables multistep reaction by integrating two identical loop reactors. Specifically, reactants A and B are synthesized in the first loop reactor and transferred to the second loop reactor to synthesize with reactant C to form the final product. These individual reactions have nano-liter volumes and are carded out in a stepwise manner in each reactor without any cross-contamination issue. To pre- cisely control the mixing efficiency in each loop reactor, we investigate the operating pressure and the operating frequency on the mixing valves for rotary mixing. This microfluidic dual loops reactor is integrated with several valves to realize the fully automated unit operation of a multistep reaction, such as metering the reactants, rotary mixing, transportation, and collecting the product. For proof of concept, CdSeZn nanopartieles are successfully synthesized in a microfluidic dual loops reactor through a fully automated mukistep reaction. Taking all of these features together, this microfluidic dual loops reactor is a general microfluidic screening platform that can synthesize various materials through a multistep reaction.

关键词： microfluidics multistep reaction rotary mixing nanoparticle

Comparison of Bacterial Profiles of Fish between Storage Conditions at Retails Using DGGE and Banding Pattern Analysis: Consumer’s Perspective

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Food and Nutrition Sciences 2012年第2期3卷 190-200页

作者： Chongtao Ge chang soo lee Zhongtang Yu Jiyoung lee College of Public Health Division of Environmental Health Sciences The Ohio State University Columbus USA Department of Animal Sciences The Ohio State University Columbus USA. Department of Food Science & Technology The Ohio State University Columbus USA Department of Food Science & Technology The Ohio State University Columbus USA 2College of Public Health Division of Environmental Health Sciences The Ohio State University Columbus USA

Bacterial profiles between storage conditions (frozen vs fresh) were compared using PCR-DGGE and banding pattern analysis. Salmon and tuna were collected and the bacteria cells were separated from fish cells using a somatic cell re-leasing agent. The results demonstrated that some were indigenous waterborne bacteria. However, the majority were identified as spoilage bacteria, pathogens and potential fecal contamination bacteria. Banding pattern analysis showed that the storage conditions were a significant factor in clustering bacteria. Frozen fish showed a smaller number of bac-terial species than fresh samples. Freezing seemed to play a role as a selective pressure by inactivating some microor-ganisms while favoring resistant ones to low temperature. The bacterial profiles seemed to be more influenced by afterharvest practices than the original environmental contamination. These findings provide consumers insight into fish quality, potential health risks of raw fish consumption, and the impact of storage conditions on bacterial group of raw fish.

关键词： Fish PCR-DGGE Bacterial Profiles Storage

Synthesis of Bifunctional Poly(Vinyl Phosphonic Acid-<i>co</i>-glycidyl Metacrylate-<i>co</i>-divinyl Benzene) Cation-Exchange Resin and Its Indium Adsorption

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Open Journal of Polymer Chemistry 2013年第4期3卷 104-112页

作者： Chi Won Hwang chang soo lee Taek Sung Hwang Department of Applied Chemistry and Biological Engineering Chungnam National University Daejeon Korea

Poly(vinyl phosphonic acid-co-glycidyl methacrylate-co-divinyl benzene) (PVGD) and PVGD containing an iminodi-acetic acid group (IPVGD), which has indium ion selectivity, were synthesized by suspension polymerization, and their indium adsorption properties were investigated. The synthesized PVGD and IPVGD resins were characterized using Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and mercury porosimetry. The cation-exchange capacity, the water uptake and the indium adsorption properties were investigated. The cation-exchange capacities of PVGD and IPVGD were 1.2 - 4.5 meq/g and 2.5 - 6.4 meq/g, respectively. The water uptakes were decreased with increasing contents of divinyl benzene (DVB). The water uptake values were 25% - 40% and 20% - 35%, respectively. The optimum adsorption of indium from a pure indium solution and an artificial indium tin oxide (ITO) solution by the PVGD and IPVGD ion-exchange resins were 2.3 and 3.5 meq/g, respectively. The indium adsorption capacities of IPVGD were higher than those of PVGD. The indium ion adsorption selectivity in the artificial ITO solution by PVGD and IPVGD was excellent, and other ions were adsorbed only slightly.

关键词： Poly(Vinyl Phosphonic Acid-co-glycidyl Methacrylate-co-divinyl Benzene) PVGD Containing an Iminodiacetic Acid Group Bifunctional Cation Exchanger Indium Tin Oxide Indium Adsorption

Aligned Ion Conduction Pathway of Polyrotaxane‑Based Electrolyte with Dispersed Hydrophobic Chains for Solid‑State Lithium–Oxygen Batteries

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Nano-Micro Letters 2025年第2期17卷 169-186页

作者： Bitgaram Kim Myeong‑chang Sung Gwang‑Hee lee Byoungjoon Hwang Sojung Seo Ji‑Hun Seo Dong‑Wan Kim Department of Materials Science and Engineering Korea University145 Anam‑RoSeongbuk‑GuSeoul 02841Republic of Korea School of Civil Environmental and Architectural EngineeringKorea University145 Anam‑RoSeongbuk‑GuSeoul 02841Republic of Korea Materials Science and Chemical Engineering Center Institute for Advanced Engineering(IAE)Yongin 17180Republic of Korea

A critical challenge hindering the practical application of lithium–oxygen batteries(LOBs)is the inevitable problems associated with liquid electrolytes,such as evaporation and safety *** study addresses these problems by proposing a modified polyrotaxane(mPR)-based solid polymer electrolyte(SPE)design that simultaneously mitigates solvent-related problems and improves ***-SPE exhibits high ion conductivity(2.8×10^(−3)S cm^(−1)at 25℃)through aligned ion conduction pathways and provides electrode protection ability through hydrophobic chain *** this mPR-SPE into solid-state LOBs resulted in stable potentials over 300 *** situ Raman spectroscopy reveals the presence of an LiO_(2)intermediate alongside Li_(2)O_(2)during oxygen *** situ X-ray diffraction confirm the ability of the SPE to hinder the permeation of oxygen and moisture,as demonstrated by the air permeability *** present study suggests that maintaining a low residual solvent while achieving high ionic conductivity is crucial for restricting the sub-reactions of solid-state LOBs.

关键词： Solid polymer electrolyte Lithium-oxygen batteries Polyrotaxane ion conductivity Hydrophobic chain

Velocity Profiles between Two Baffles in a Shell and Tube Heat Exchanger

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Journal of Thermal Science 2015年第4期24卷 356-363页

作者： Tae-Hyun chang chang-Hoan lee Hae-soo lee Kwon-soo lee Senior Research Fellow of RESEAT Korea Institute of Science and Technology Information Korea Institute of Science and Technology Information Postdoctoral Research Fellow School of Mechanical Engineering of Kyungnam University International University of Korea

Heat exchangers are extensively utilized for waste heat recovery,oil refining,chemical processing,and steam *** this study,velocity profiles are measured using a 3D particle image velocimetry(PIV)system between two baffles in a shell and tube heat exchanger for parallel and counter *** PIV and computational fluid dynamics results show the occurrence of some strong vectors near the *** vectors are assumed due to the clearance between the inner tubes and the front ***,the major parts of the vectors are moved out through the bottom opening of the rear baffle,and other vectors produce a large circle between the two *** simulations are conducted to investigate the effects of the baffle on the heat exchanger using the Fluent *** k-εturbulence model is employed to calculate the flows along the heat exchanger.

关键词： Baffle P1V Shell and tube heat exchanger Cut off ratio CFD

Velocity Profiles between Two Baffles in a Horizontal Circular Tube

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Journal of Thermal Science 2014年第6期23卷 544-551页

作者： Tae-Hyun chang Hae-soo lee Keon-Je Oh Doeg Hee Doh chang-Hoan lee Senior Research Fellow of RESEAT Korea Institute of Science and Information Postdoctoral Research Fellow School of Mechanical Engineering of Kyungnam University School of Mechanical Engineering Kyungnam University Division of Mechanical and Energy Systems Engineering Korea Marine and Ocean University Korea Institute of Science and Technology Information

The shell and tube heat exchanger is an essential part of a power plant for recovering heat transfer between the feed water of a boiler and the wasted *** baffles are also an important element inside the heat *** materials influence the flow pattern in the *** influence of baffles in the velocity profiles was observed using a three-dimensional particle image velocimetry around baffles in a horizontal circular *** velocity of the particles was measured before the baffle and between them in the test *** show that the flows near the front baffle flow were parallel to the vertical wall,and then concentrate on the upper opening of the front *** flows circulate in the front and rear *** flow profiles are related to the Reynolds number(Re) or the flow *** velocity profiles at lower Re number showed a complicated mixing,concentrating on the lower opening of the rear baffle as front *** flow was employed in this study,which was produced using tangential velocities at the *** the entrance of the front baffle,the velocity vector profiles with swirl were much different from that without ***,velocities between two baffles are not much different from those without swirl.

关键词： Baffle Shell and tube Tangential inlet Swirl Particle image velocimetry

Microstructure of fast tool servo machining on copper alloy

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中国有色金属学会会刊：英文版 2012年第S3期22卷 820-824页

作者： Hong LU soo-chang CHOI Sang-min lee Deug-woo lee Department of Nano Fusion Technology Pusan National University Korea Institute of Machinery & Materials Department of Nano Mechatronics Engineering Pusan National University

The development of the fast tool servo (FTS) for precision machining was *** micron machining performance of a piezoelectric-assisted FTS on copper alloy was *** results indicate that the quality of the microstructure depends mainly on two important factors:the cutting speed (or spindle speed) and the driving frequency of the *** excessive driving frequency increases the formation of *** effect of the clearance angle of the diamond tool on the microstructure machining precision was also investigated.

关键词： fast tool servo microstructure piezoelectric diamond machining copper alloy

Recoverable SnO_2-Based Sensors Promoted with MoO_3 and Sb_2O_3 for the Detection of DMMP

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稀有金属材料与工程 2006年第A3期35卷 155-156页

作者： Woo Suk lee Ho Yun Choi soo Chool lee soo Jae lee Duk Dong lee Jeung soo Huh Jae chang Kim Department of Chemical Engineering Kyungpook National UniversityDaegu 702-701Korea School of Electrical Engineering and Computer Science Kyungpook National UniversityDaegu 702-701Korea Department of Materials Science and Metallurgy Kyungpook National UniversityDaegu 702-701Korea

The sensitivity and the recovery behavior of SnO_2-based gas sensor prepared from a commercial SnO_2 powder were tested under the low concentration of DMMP(0.5μg/g) in the flow system at 350℃.In order to improve the sensitivity of the sensor,promoters such as NiO,Nb_2O_5,MoO_3,and Sb_2O_3 were added into SnO_2 *** sensitivities were increased up to 80% from 50% but they were not *** the SnO2-based gas sensor promoted with MoO_3 and Sb_2O_3 was recovered after detection of DMMP,although the recovery rate was *** particular,the SnO_2-based sensor promoted with 5wt% of MoO_3 and 1wt% of Sb_2O_3 simultaneously showed an complete recovery ability,though its sensitivity was 40% which was lower than that of SnO_2 gas sensor without *** ability was discussed in terms of catalytic roles of promoters.

关键词： SnO2 MoO3 Sb2O3 sensor,recovery DMMP

Effects of an Urban Park and Residential Area on the Atmospheric CO_2 Concentration and Flux in Seoul,Korea

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Advances in Atmospheric Sciences 2013年第2期30卷 503-514页

作者： Moon-soo PARK Seung Jin JOO chang Seok lee Center for Atmospheric and Environmental Modeling Seoul 151 919Korea Life and Environmental Engineering Seoul Women's UniversitySeoul 139 774Korea

The CO2 concentrations and fluxes over an urban forest site （Namsan） and an urban residential region （Boramae） in Seoul, Korea, during the non-growing season （2 4 March 2011）, the growing season （10-12 June 2011）, and the late-growing season （22-24 September 2011） were analyzed. The CO2 concentrations of two sites showed nearly the same diurnal variation, with a maximum value occurring during the night and a minimum value occurring during daytime, as well as the same seasonal variation, with a maximum value during the non-growing season （early spring） and a minimum value during the growing season （summer）. The CO2 flux over the urban forest did not show any typical diurnal variation during the non-growing season, but did show diurnal variation with a small positive value during the night and a large negative value during daytime in the growing and late-growing seasons due to photosynthesis in the urban forest. The CO2 flux over the urban residential region showed a positive daily mean value for all periods, with large values during the non-growing season and small values during the growing season, and it also showed diurnal variation with two maxima at 0600-1000 LST and 1800-2400 LST, and two minima at 0300-0600 LST and 1100-1500 LST, and was strongly correlated with the use of liquefied natural gas for cooking and heating by surrounding houses.

关键词： C02 concentration C02 flux Seoul urban forest urban residential region