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Etching characteristics of thin SiON films using a liquefied perfluorocarbon precursor of C_6F_(12)O with a low global warming potential

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Plasma Science and Technology 2020年第10期22卷 135-144页

作者： Junmyung lee Yunho NAM Jongchan lee Hyun woo lee Kwang-Ho KWON Department of Control and Instrumentation Engineering Korea UniversitySejong 30019Republic of Korea Department of Aeronautic Computer Engineering Hanseo UniversitySeosan 31962Republic of Korea

Perfluorocarbon gas is widely used in the semiconductor ***,perfluorocarbon has a negative effect on the global environment owing to its high global warming potential(GWP) *** alternative solution is ***,we evaluated the possibility of replacing conventional perfluorocarbon etching gases such as CHF_3 with C_6F_(12)O,which has a low GWP and is in a liquid state at room *** this study,silicon oxynitride(SiON) films were plasma-etched using inductively coupled CF4+C_6F_(12)O+O_2 mixed ***,the etching characteristics of the film,such as etching rate,etching profile,selectivity over Si,and photoresist,were investigated.A double Langmuir probe was used and optical emission spectroscopy was performed for plasma *** addition,a contact angle goniometer and x-ray photoelectron spectroscope were used to confirm the change in the surface properties of the etched SiON film ***,the etching characteristics of the C_6F_(12)O mixed plasma exhibited a lower etching rate,higher SiON/Si selectivity,lower plasma damage,and more vertical etched profiles than the conventional CHF_3 mixed *** addition,the C_6F_(12)O gas can be recovered in the liquid state,thereby decreasing global *** results confirmed that the C_6F_(12)O precursor can sufficiently replace the conventional etching gas.

关键词： global warming potential perfluorocarbon silicon oxynitride etching characteristics liquid-state perfluorocarbon

Creep and tensile properties of press molding joined GMT-sheets

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Transactions of Nonferrous Metals Society of China 2011年第A01期21卷 170-174页

作者： Jin-woo KIM Dong-Gi lee Center for NDE Iowa State University Department of Mechatronics Engineering Chosun University

GMT-sheet is used in automobile bumper with high rigidity and strength, and its joining strength is influenced by lap length, one of the joined molding conditions. Fracture strength was calculated by dividing fracture load with cross-sectional area. Total five repeated measurements were made to obtain the average value. Tensile test was conducted at room temperature for 10 specimens. In addition, the effect of compression ratio on creep and tensile performance during lap joined molding was discussed. With increasing lap length, the lap joining efficiency of GMT-sheet was increased. However, higher compression ratio reduced the joining efficiency. Creep test on GMT-sheet showed abrupt fracture without tertiary creep. This can be explained by the weak thermal resistance of the resin. If GMT-sheet was exposed to high temperature for a long time, it was easily failed by external force.

关键词： GMT-sheet randomly oriented composite unidirectional oriented composite compression ratio lap joint

Photo-Induced Electron Spin Polarization in a Narrow Band Gap Semiconductor Nanostructure

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Chinese Physics Letters 2012年第11期29卷 186-190页

作者： A.John Peter Chang woo lee Department of Chemical Engineering and Green Energy Center College of EngineeringKyung Hee University1 SeochunGihungYonginGyeonggi 446-701S.Korea

Photo-induced spin dependent electron transmission through a narrow gap InSb/InGa_(x)Sb_(1-x) semiconductor symmetric well is theoretically studied using transfer matrix *** transparency of electron transmission is calculated as a function of electron energy for different concentrations of *** spin-polarized photon assisted resonant tunnelling in the heterostructure due to Dresselhaus and Rashba spin-orbit coupling induced splitting of the resonant level and compressed spin-polarization are *** results show that Dresselhaus spin-orbit coupling is dominant for the photon effect and the computed polarization efficiency increases with the photon effect and the gallium concentration.

关键词： polarization resonant photon

A Self‑Regenerable Fiber Sloughing Its Heavy Metal Skin for Ultrahigh Separation Capability

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Advanced Fiber Materials 2023年第6期5卷 2127-2142页

作者： Youngkyun Jung Ji Su Park Kyung‑Won Jung Young gun Ko Jae‑woo Choi Center for Water Cycle Research Korea Institute of Science and TechnologySeoul 02792Republic of Korea Center for Bionics Korea Institute of Science and TechnologySeoul 02792Republic of Korea Department of Chemical Engineering and Materials Science Sangmyung UniversitySeoul 03016Republic of Korea Division of Energy&Environment Technology KIST SchoolKorea University of Science and Technology(UST)Seoul 02792Republic of Korea

Developing efficient separation materials for recovering metal resources from aqueous environments is crucial for the sustainable water–food–energy nexus,which addresses the interdependence between energy production,water production,and energy *** material-based separation processes have demonstrated outstanding ***,electric energy and chemicals are used to frequently replace the separation materials used in such processes owing to their short life *** study presents a methodology for designing the self-regenerable fiber(SRF)according to the types of metals through a self-regeneration *** SRF can semi-permanently recover the metal resources from water through a repetitive adsorption–crystallization–detachment process of metal ions on its *** ionic metal resources are adsorbed and crystallized with the counter-anions on the SRF ***,the metal crystals are self-detached from the SRF surface by the collision between the crystals and curvature and non-sticky surface of the ***,a module containing the SRF maintains its metal recovery capability even during continuous injection of the metal solution without its *** findings highlight the significance of interfacial engineering and further guide the rational design of energy/environmentally friendly resource recovery modules.

关键词： Self-regeneration model Self-regenerable fiber Semi-permanent adsorption capability Metal crystal growth-detachment

Feasibility Study of R134a/R404a Cascade Heat Pump Cycle in Heat Pump Dryers with Electrical Heaters at Low Temperatures

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Journal of Thermal Science 2015年第5期24卷 463-467页

作者： Ji woo Jeong Young Lim lee Dept. of Mechanical Engineering Kongju National University Dept. of Mechanical and Automotive Engineering Kongju National University

Heat pump cycles have been widely applied to dryers for their high efficiency. However, low–efficiency electrical heaters are often used during early drying stage for frozen foods or winter since a standard heat pump cycle cannot operate at low temperature. This study introduced cascade heat pumps replacing electrical heaters to improve dryer performance at low temperatures. Experiments were performed to examine changes in performance of the cascade heat pump dryers in relation to ambient temperature, low-stage cycle mass flow rate, and high-stage cycle mass flow rate. The results showed a significant improvement in low-temperature dryer performance with the introduction of cascade heat pump cycles.

关键词： Cascade cycle R134a/R404a Heat pump dryer COP Energy efficiency

Transparent Supercapacitors: From Optical Theories to Optoelectronics Applications

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Energy & Environmental Materials 2020年第3期3卷 265-285页

作者： Sang-woo Kim Sang-Young lee Department of Energy Engineering School of Energy and Chemical EngineeringUlsan National Institute of Science and Technology(UNIST)Ulsan 689-798Korea

The ever-increasing demand for smart optoelectronics spurs the relentless pursuit of transparent wireless devices as a game-changing technology that can provide unseen visual information behind the *** enable successful operation of the transparent wireless devices,their power sources should be highly transparent in addition to acquiring reliable electrochemical *** various transparent power sources,supercapacitors(SCs)have been extensively investigated as a promising candidate due to their exceptional cyclability,power capability,material diversity,and scalable/low-cost ***,we describe current status and challenges of transparent SCs,with a focus on their core materials,performance advancements,and integration with application devices.A special attention is devoted to transparent conductive electrodes(TCEs)which act as a keyenabling component in the transparent *** on fundamental understanding of optical theories and operating principles of transparent materials,we comprehensively discuss materials chemistry,structural design,and fabrication techniques of *** addition,noteworthy progresses of transparent SCs are briefly overviewed in terms of their architectural design,opto-electrochemical performance,flexibility,form factors,and integration compatibility with transparent flexible/wearable devices of ***,development direction and outlook of transparent SCs are explored along with their viable roles in future application fields.

关键词： energy storage flexibility optoelectronics transparent conductive electrodes transparent supercapacitors

Hematologic diseases: High risk of Clostridium difficile associated diarrhea

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World Journal of Gastroenterology 2014年第21期20卷 6602-6607页

作者： Tae-Geun Gweon Myung-Gyu Choi Myong Ki Baeg Chul-Hyun Lim Jae Myung Park In Seok lee Sang woo Kim Dong-gun lee Yeon Joon Park Jong wook lee Division of Gastroenterology Department of Internal MedicineSeoul St Mary’s hospitalThe Catholic University of KoreaCollege of MedicineSeoul 137-701South Korea Division of Infectious Diseases Department of Internal MedicineSeoul St Mary’s hospitalThe Catholic University of KoreaCollege of MedicineSeoul 137-701South Korea Department of Laboratory Medicine Seoul St Mary’s hospitalThe Catholic University of KoreaCollege of MedicineSeoul 137-701South Korea Division of Hematologic Diseases Department of Internal MedicineSeoul St Mary’s hospitalThe Catholic University of KoreaCollege of MedicineSeoul 137-701South Korea

AIM: To investigate the incidence and clinical outcome of Clostridium difficile (C. difficile) associated diarrhea (CDAD) in patients with hematologic disease.

关键词： Clostridium difficile associated diarrhea Incidence Clinical outcome Patients with hematologic disease Intravenous immunoglobulin

Response of phenology- and yield-related traits of maize to elevated temperature in a temperate region

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The Crop Journal 2017年第4期5卷 305-316页

作者： Dana Shim Kyu-Jong lee Byun-woo lee Department of Plant Science Seoul National University Seoul 151-921 Republic of Korea Research Institute for Agriculture and Life Sciences Seoul National University Seoul 151-921 Republic of Korea

Extreme high temperatures detrimental to maize production are projected to occur more frequently with future climate *** and yield-related traits were investigated under several levels of elevated temperature in two early-maturing hybrid cultivars:Junda 6(grown in northeastern China)and Chalok 1(grown in South Korea).They were cultivated in plastic houses in Suwon,Korea(37.27°N,126.99°E)held at target temperatures of ambient(AT),AT+1.5°C,AT+3°C,and AT+5°C at one sowing date in 2013 and three different sowing dates in *** and reproductive growth durations showed variation depending on sowing date,experimental year,and *** duration tended to decrease,but not necessarily,with temperature elevation,but somewhat increased again above a certain *** temperature-dependent variation was greater during grain filling than in the vegetative period before *** temperature showed no significant effects on duration or peak dates of silking and anthesis,and thus on anthesis–silking *** yield tended to decrease with temperature elevation above ambient,showing a sharper linear decrease with mean growing season temperature increase in Junda 6 than in Chalok *** decrease in kernel number accounted for a much greater contribution to the yield reductions due to temperature elevation than did the decrease in individual kernel weight in both *** harvestable kernel weight was not significantly affected by temperature elevation *** number showed a linear decrease with mean growth temperature from early ear formation to early grain-filling stage,with Junda 6 showing a much severer decrease than Chalok *** number reduction due to temperature elevation was attributable more to the decrease in differentiated ovule number than to the decrease in kernel set in Chalok 1,but largely to the decrease of kernel set in Junda 6.

关键词： Maize Elevated temperature Phenology Yield Yield-related traits

Biomass seaweed-derived n itrogen self-doped porous carb on anodes for sodium-ion batteries:Insights into the structure and electrochemical activity

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Journal of Energy Chemistry 2022年第1期31卷 286-295,I0008页

作者： Chenrayan Senthil Jae woo Park Nitheesha Shaji Gyu Sang Sim Chang woo lee Department of Chemical Engineering(Integrated Engineering)&Center for the SMART Energy Platform College of EngineeringKyung Hee University1732 Deogyeong-daeroCihuengYonginGyeonggi 17104South Korea

Sustainable transformation and efficient utilization of biomasses and their derived materials are environ-mentally as well as economically compliant *** seaweed-derived nitrogen self-doped porous carbon with tailored surface area and pore structures are prepared through carb on izatio n and *** in fluence of carb on ization temperature on morphology,surface area,and heteroatom dopants are investigated to optimize sodium-ion storage ***-derived nitrogen selfdoped activated carbon(SAC)as anode materials for sodium-ion batteries exhibits remarkable reversible capacity of 303/192 mAh g^(-1) after 100/500 cycles at current densities of 100/200 mA g^(-1) respectively,and a good rate *** interconnected and porous conducting nature along with the heteroatom dopant role in creating defective sites and charge stabilization are favorable for ion storage and diffusion and electron transport,indicating the electrodes can offer improved electrochemical *** addition,post-mortem analysis of the cycled carbon electrodes through ex-situ tools demonstrates the sodium-ion storage mechanism.

关键词： Biomass Heteroatom self-doping Porous carbon Anode Sodium-ion batteries Post-mortem ex-situ analysis