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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

A fully automated framework for helicopter rotor blades design and analysis including aerodynamics,structure, and manufacturing

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Chinese Journal of Aeronautics 2016年第6期29卷 1602-1617页

作者： Ngoc Anh Vu Jae woo Lee Tuan Phuong nam Le Song Thanh Thao Nguyen Division of Computational Mechatronics Institute for Computational Science Ton Duc Thang University Faculty of Electrical & Electronics Engineering Ton Duc Thang University Department of Aerospace Information Engineering Konkuk University Faculty of Mechanical Engineering Industrial University of Ho Chi Minh City Department of Aerospace Engineering Ho Chi Minh City University of Technology Vietnam National University-Ho Chi Minh City

This study describes an integrated framework in which basic aerospace engineering aspects(performance, aerodynamics, and structure) and practical aspects(configuration visualization and manufacturing) are coupled and considered in one fully automated design optimization of rotor blades. A number of codes are developed to robustly perform estimation of helicopter configuration from sizing, performance analysis, trim analysis, to rotor blades configuration representation. These codes are then integrated with a two-dimensional airfoil analysis tool to fully design rotor blades configuration including rotor planform and airfoil shape for optimal aerodynamics in both hover and forward flights. A modular structure design methodology is developed for realistic composite rotor blades with a sophisticated cross-sectional geometry. A D-spar cross-sectional structure is chosen as a baseline. The framework is able to analyze all realistic inner configurations including thicknesses of D-spar, skin, web, number and ply angles of layers of each composite part,and materials. A number of codes and commercial software(ANSYS, Gridgen, VABS, Pre VABS,etc.) are implemented to automate the structural analysis from aerodynamic data processing to sectional properties and stress analysis. An integrated model for manufacturing cost estimation ofcomposite rotor blades developed at the Aerodynamic Analysis and Design Laboratory(AADL),Aerospace Information Engineering Department, Konkuk University is integrated into the framework to provide a rapid and dynamic feedback to configuration design. The integration of three modules has constructed a framework where the size of a helicopter, aerodynamic performance analysis, structure analysis, and manufacturing cost estimation could be quickly investigated. All aspects of a rotor blade including planform, airfoil shape, and inner structure are considered in a multidisciplinary design optimization without an exception of critical configuration.

关键词： Design optimization Helicopter rotor blades Integrated framework Modular structure design methodology Perform estimation

Laser-Induced Indium-Diffusion into Cadmium Sulfide Thin Film for Solar Cell Applications

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Chinese Physics Letters 2012年第12期29卷 185-187页

作者： KIM nam-Hoon MYUNG Kuk Do LEE woo-Sun Department of Electrical Engineering Chosun UniversityGwangju 501-759Republic of Korea

Laser-induced diffusion is employed to dope indium(In)into sputtering-deposited cadmium sulfide(CdS)thin *** increased optical band gap energy from 2.52 to 2.60 eV with maintenance of high optical transmittance about 60 nm in the 200-nm-thick films,the enhanced mobility over 42.5 cm^(2)/V·s,and the decreased resistivity to 1.42×10^(-3)Ω·cm are successfully obtained to be advantageous for a window layer in solar cells.

关键词： Diffusion resistivity sulfide

Effect of open-field experimental warming on the leaf phenology of oriental oak (Quercus variabilis) seedlings

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Journal of Plant Ecology 2014年第6期7卷 559-566页

作者： Saerom Han Haegeun Chung nam Jin Noh Sun Jeoung Lee wooyong Jo Tae Kyung Yoon Koong Yi chan-woo Park Suin Ko Yowhan Son Department of Environmental Science and Ecological Engineering Graduate SchoolKorea UniversitySeoul 136-713Korea Department of Environmental Engineering Konkuk UniversitySeoul 143-701Korea River Basin Research Center Gifu UniversityGifu 501-1193Japan Forest and Climate change Center Korea Forest Research InstituteSeoul 130-712Korea Hanlim Patent and Law Office Seoul 152-050Korea Forest Soil and Water Conservation Division Korea Forest Research InstituteSeoul 130-712Korea Environmental Policy Research Group Korea Environment InstituteSeoul 122-706Korea

Aims An open-field warming experiment enables us to test the effects of projected temperature increase on change in plant phenology with fewer confounding factors and to study phenological response to temperature ranges beyond natural *** study aims to(i)examine the effect of temperature increase on leaf unfold-ing and senescence of oriental oak(Quercus variabilis Blume)under experimental warming and(ii)measure temperature-related parameters used in estimating phenological response to tempera-ture *** Using an open-field warming system with infrared heaters,we increased the air temperature by~3℃ in the warmed plots compared with that of the control plots consistently for 2 *** unfolding and senescence dates of *** seedlings were recorded and temperature-related phenological parameters were *** Findings The timing of leaf unfolding was advanced by 3-8 days(1.1-3.0 days/℃)and the date of leaf senescence was delayed by 14-19 days(5.0-7.3 days/℃)under elevated air ***,the cumulative degree days(CDD)of leaf unfolding were not significantly changed by experimental warming,which suggest the applicability of a constant CDD value to estimate the change in spring leaf phe-nology under 3℃ *** ranges of advancement and temperature sensitivity in spring phenology and delayed autumn phe-nology and proposed temperature parameters from this study might be applied to predict future phenological change.

关键词： climate change cumulative degree days experimental warming leaf senescence leaf unfolding

Overcoming the penetration depth limit in optical microscopy:Adaptive optics and wavefront shaping

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Journal of Innovative Optical Health Sciences 2019年第4期12卷 3-20页

作者： Cheolwoo Ahn Byungjae Hwang Kibum nam Hyungwon Jin Taeseong woo Jung-Hoon Park Department of Biomedical Engineering Ulsan National Institute of Science and Technology(UNIST)Ulsan South Korea

Despite the unique advantages of optical microscopy for molecular specific high resolution imaging of living structure in both space and time,curent applications are mostly limited to research *** is due to the aberrations and multiple scattering that is induced by the inhomogeneous refractive boundaries that are inherent to biological ***,recent developments in adaptive optics and wavefront shaping have shown that high resolution optical imaging is not fundamentally limited only to the observation of single cells,but can be significantly enhanced to realize deep tissue *** provide insight into how these two closely related fields can expand the limits of bio imaging,we review the recent progresses in their performance and applicable range of studies as well as potential future research directions to push the limits of deep tissuse imnaging.

关键词： Adaptive optics wavefront shaping optical aberration multiple scattering in-viuo imaging

Self‑Powered Airflow Sensor Based on Energy Harvesting of Ventilation Air in Buildings

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Advanced Fiber Materials 2023年第5期5卷 1788-1798页

作者： Moon Hyun Chung Seunghwan Yoo woo‑nam Jung Hakgeun Jeong Kyung‑Hwa Yoo Department of Physics Yonsei University50 Yonsei‑RoSeodaemun‑GuSeoul 03722Republic of Korea Energy ICT Convergence Research Department Energy Efficiency Research DivisionKorea Institute of Energy Research152 Gajeong‑RoYuseong‑GuDaejeon 34129Republic of Korea Advanced Combustion Power Lab Energy Efficiency Research DivisionKorea Institute of Energy Research152Gajeong‑RoYuseong‑GuDaejeon 34129Republic of Korea Department of Mechanical Engineering Korea Advanced Institute of Science and Technology(KAIST)291 Daehak‑RoYuseongDaejeon 34141Republic of Korea

Heating,ventilation,and air conditioning(HVAC)systems account for one-third of the total energy consumption in office *** use of airflow measurements to control the operation of HVAC systems can reduce energy consumption;thus,a sensor capable of monitoring airflow in a duct system is *** nanogenerators(TENGs)can be utilized as self-powered sensors in airflow-driven TENGs(ATENGs)as self-powered *** employing ferroelectric materials and surface modifications,the surface charges of TENGs can be *** this study,fibrous-mat TENGs were prepared using ferroelectric materials consisting of poly(vinylidene fluoride-co-trifluoroethylene)(PVDF-TrFE)and polyamide 11(nylon-11).And these materials were subsequently ***(3,4-ethylenedioxythiophene):poly(styrenesulfonate)was added to PVDF-TrFE to enhance the ferroelectric crystalline phase.X-ray diffraction analysis revealed that this incorporation affects theβ*** addition,the surface of nylon-11 was modified using the electrospray technique for post-treatment,thereby improving the interfacial adhesion between the *** materials were then utilized in fibrous-mat ATENGs(FM-ATENGs)to demonstrate their practical *** FM-ATENGs can be effectively used in an Arduino airflowcheck sensor,showcasing their potential for application in HVAC systems,to enhance airflow control and energy efficiency.

关键词： HVAC Airflow-driven triboelectric nanogenerator Building energy harvesting Fibrous mat Airflow sensor

Multiscale Image Dehazing and Restoration:An Application for Visual Surveillance

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Computers, Materials & Continua 2022年第1期70卷 1-17页

作者： Samia Riaz Muhammad Waqas Anwar Irfan Riaz Hyun-woo Kim Yunyoung nam Muhammad Attique Khan Department of Computer Science COMSATS University IslamabadWah Campus47040Pakistan Department of Computer Science COMSATS University IslamabadLahore CampusLahorePakistan Department of Electronics and Communication Engineering Hanyang UniversityAnsanKorea Department of ICT Convergence Soonchunhyang UniversityAsan31538Korea Department of Computer Science HITEC University TaxilaTaxila47080Pakistan

The captured outdoor images and videos may appear blurred due to haze,fog,and bad weather *** droplets or dust particles in the atmosphere cause the light to scatter,resulting in very limited scene discernibility and deterioration in the quality of the image ***,image dehazing has gainedmuch popularity because of its usability in a wide variety of *** algorithms have been proposed to solve this ill-posed *** algorithms provide quite promising results in some cases,but they include undesirable artifacts and noise in haze patches in adverse *** of these techniques take unrealistic processing time for high image *** this paper,to achieve real-time halo-free dehazing,fast and effective single image dehazing we propose a simple but effective image restoration technique using multiple *** will improve the shortcomings of DCP and improve its speed and efficiency for high-resolution images.A coarse transmissionmap is estimated by using the minimumof different size *** a cascaded fast guided filter is used to refine the transmission *** introduce an efficient scaling technique for transmission map estimation,which gives an advantage of very low-performance degradation for a highresolution *** performance evaluation,quantitative,qualitative and computational time comparisons have been performed,which provide quiet faithful results in speed,quality,and reliability of handling bright surfaces.

关键词： Dehaze defog pixel minimum patch minimum edge preservation

Clinical application of repetitive transcranial magnetic stimulation in stroke rehabilitation

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Neural Regeneration Research 2012年第8期7卷 627-634页

作者： Joonho Shin EunJoo Yang KyeHee Cho Carmelo L Barcenas woo Jin Kim nam-Jong Paik Department of Rehabilitation Medicine Bundang Hospital College of Medicine Seoul National University

Proper stimulation to affected cerebral hemisphere would promote the functional recovery of patients with stroke. Effects of repetitive transcranial magnetic stimulation on cortical excitability can be can be altered by the stimulation frequency, intensity and duration. There has been no consistent recognition regarding the best stimulation frequency and intensity. This study reviews the intervention effects of repetitive transcranial stimulation on motor impairment, dysphagia, visuospatial neglect and aphasia, and summarizes the stimulation frequency, intensity and area for repetitive transcranial magnetic stimulation to yield the best therapeutic effects.

关键词： stroke repetitive transcranial magnetic stimulation rehabilitation review

Tailoring of Mechanical Properties of Indirect Hot Stamping Steel Tubes by Laser Assisted Local Rapid Heating

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Journal of Iron and Steel Research International 2016年第9期23卷 949-954页

作者： Mahmudun Nabi CHOWDHURY Ju-ri KIM Sung-tae HONG Jin-wook JUNG Heung-nam HAN Sang-woo SO Schoolof Mechanical Engineering University of Ulsan Ulsan44610 South Korea Department of Materials Science & Engineering and Centre for Iron & Steel Research RIAM Seoul National University Seoul 08826 South Korea Automotive Parts Institute & Centre Ulsan Technopark Ulsan 44412 South Korea

The effect of laser assisted local heating on the mechanical properties of a hot stamping steel tube was in vestigated. A heated region with a spiral shape was generated on the surface of the tube by combining the linear movement of the laser and the rotation of the tube. The results of axial crush tests show that the laser assisted local heating can be effectively used to modify the mechanical performance of the tube. A microstructural analysis confirms that the laser locally induces a martensitic phase transformation in the heated region and results in inhomogeneous microstructures alon- the length of the tube.

关键词： local heating laser hot stamping steel tube

Effect of solid-solution strengthening on deformation mechanisms and strain hardening in medium-entropy V_(1-x)Cr_(x)CoNi alloys

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Journal of Materials Science & Technology 2022年第13期108卷 270-280页

作者： Hyun Chung Dae woong Kim woo Jin Cho Heung nam Han Yuji Ikeda Shoji Ishibashi Fritz Körmann Seok Su Sohn Department of Materials Science and Engineering Korea UniversitySeoul 02841South Korea Center for High Entropy Alloys Pohang University of Science and TechnologyPohang 37673South Korea Department of Materials Science and Engineering and Research Institute of Advanced Materials Seoul National UniversitySeoul 08826South Korea Institute for Materials Science University of StuttgartPfaffenwaldring 55Stuttgart 70569Germany Computational Materials Design Max-Planck-Institut für Eisenforschung GmbHMax-Planck-Strabe 1Düsseldorf 40237Germany Research Center for Computational Design of Advanced Functional Materials(CD-Fmat) National Institute of Advanced Industrial Science and Technology(AIST)TsukubaIbaraki 305-8568Japan Department of Materials Science and Engineering Delft University of TechnologyMekelweg2Delft 2628 CDthe Netherlands

High-and medium-entropy alloys(HEAs and MEAs)possess high solid-solution *** investigations have been conducted on its impact on yield strength,however,there are limited reports regarding the relation between solid-solution strengthening and strain-hardening *** addition,no attempt has been made to account for the dislocation-mediated plasticity;most works focused on twinning-or transformation-induced plasticity(TWIP or TRIP).In this work we reveal the role of solidsolution strengthening on the strain-hardening rate via systematically investigating evolutions of deformation structures by controlling the Cr/V ratio in prototypical V_(1-x)Cr_(x)CoNi *** the TWIP of CrCoNi with the dislocation slip of V_(0.4)Cr_(0.6)CoNi,the hardening rate of CrCoNi was superior to slip-band refinements of V_(0.4)Cr_(0.6)CoNi due to the dynamic Hall-Petch ***,as V content increased further to V_(0.7)Cr_(0.3)CoNi and VCoNi,their rate of slip-band refinement in V_(0.7)Cr_(0.3)CoNi and VCoNi with high solid-solution strength surpassed that of *** it is generally accepted in conventional alloys that deformation twinning results in a higher strain-hardening rate than dislocation-mediated plasticity,we observed that the latter can be predominant in the former under an activated huge solid-solution strengthening *** high solid-solution strength lowered the cross-slip activation and consequently retarded the dislocation rearrangement rate,i.e.,the dynamic *** delay in the hardening rate decrease,therefore,increased the strain-hardening rate,results in an overall higher strain-hardening rate of V-rich alloys.

关键词： Medium-entropy alloy Tensile property Solid-solution strength Strain-hardening rate Stacking fault energy