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Surface exsolution and local atomic structure of amorphous CeTiO_x

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journal of Rare Earths 2019年第2期37卷 160-165页

作者： seung-Hyeon jo Soonok Kim Jiseung Ryu Dae-seung Cho Bora Jeong Heesoo lee Department of Materials Science and Engineering Pusan National University Department of Naval Architecture & Ocean Engineering Pusan National University Green Materials & Processes Group Ulsan Regional Division Korea Institute of Industrial Technology

We made precipitated nano-ceria(~5 nm) on the surface of the catalyst by heat treatment of Cesupersaturated amorphous CeTiOxto improve the oxygen storage properties of CeO_2. The catalysts were prepared by sol-gel methods and TiO_2 nanoparticles were preferentially generated as a core material to form selective Ce-supersaturated structure on the catalyst surface. Reaction temperature and amount of doping element are optimized to induce selective crystallization of CeO_2. Cee Ce(2 nd shell)bond around 0.38 nm of Ce L3-edge extended X-ray absorption fine structure is reduced and nanostructure of precipitated ceria on the surface is observed by HREM. The catalyst is present as amorphous with precipitated nano-CeO_2 on the surface. The de-NOxefficiency of the catalyst, which has precipitated CeO_2, improves by ~50% owing to the simultaneous reactions of the nano CeO_2 and the amorphous CeTiO_x.

关键词： Ce-Ti oxide Exsolution Amorphous catalyst Local atomic structure De-NO_x efficiency Rare earths

Parasitic Robot System for Waypoint Navigation of Turtle

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journal of Bionic Engineering 2017年第2期14卷 327-335页

作者： Dae-Gun Kim Serin lee Cheol-Hu Kim Sungho jo Phill-seung lee Department of Mechanical Engineering Korea Advanced Institute of Science and Technology (KAIST) 373-1 Guseong-dong Yuseong-gu Daejeon 34141 Republic of Korea Institute for Infocomm Research 1 Fusionopolis Way #21-01 Connexis Singapore Department of Computer Science Korea Advanced Institute of Science and Technology (KAIST) 373-1 Guseong-dong Yuseong-gu Daejeon 34141 Republic of Korea

In research on small mobile robots and biomimetic robots, locomotion ability remains a major issue despite many advances in technology. However, evolution has led to there being many real animals capable of exceUent locomotion. This paper presents a ＂parasitic robot system＂ whereby locomotion abilities of an animal are applied to a robot task. We chose a turtle as our first host animal and designed a parasitic robot that can perform ＂operant conditioning＂. The parasitic robot, which is attached to the turtle, can induce object-tracking behavior of the turtle toward a Light Emitting Diode （LED） and positively reinforce the behavior through repeated stimulus-response interaction. After training sessions over five weeks, the robot could successfully control the direction of movement of the trained turtles in the waypoint navigation task. This hybrid animal-robot interaction system could provide an alternative solution to some of the limitations of conventional mobile robot systems in various fields, and could also act as a useful interaction system for the behavioral sciences.

关键词： parasitic robot operant conditioning waypoint navigation red-eared slider trachemys scripta elegans

Remote Navigation of Turtle by Controlling Instinct Behavior via Human Brain-computer Interface

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journal of Bionic Engineering 2016年第3期13卷 491-503页

作者： Cheol-Hu Kim Bongjae Choi Dae-Gun Kim Serin lee Sungho jo Phill-seung lee Department of Mechanical Engineering Korea Advanced Institute of Science and Technology (KAIST) 373-1 Guseong-dong Yuseong-gu Daejeon 34141 Republic of Korea School of Computing Science Korea Advanced Institute of Science and Technology (KAIST) 373-1 Guseong-dong Yuseong-gu Daejeon 34141 Republic of Korea Instituteforlnfocomm Research 1 Fusionopolis Way #21-01 Connexis (South Tower) 138632 Singapore

Brain-Computer Interface （BCI） techniques have advanced to a level where it is now eliminating the need lor hand-based activation. This paper presents a novel attempt to remotely control an animal＇s behavior by human BCI using a hybrid of Event Related Desynchronization （ERD） and Steady-State Visually Evoked Potential （SSVEP） BCI protocols. The turtle was chosen as the target animal, and we developed a head-mounted display, wireless communication, and a specially designed stimulation device for the turtle. These devices could evoke the turtle＇s instinctive escape behavior to guide its moving path, and turtles were remotely controlled in both indoor and outdoor environments. The system architecture and design were presented. To demon- strate the feasibility of the system, experimental tests were performed under various conditions. Our system could act as a framework for future human-animal interaction systems.

关键词： brain-computer interface turtle (Trachemys scripta elegans) remote navigation instinct behaviour escape be- havior

Photocatalytic decomposition of mobile-source related pollutants using a continuous-flow reactor

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journal of Environmental Sciences 2010年第3期22卷 460-466页

作者： Wan-Kuen jo seung-Ho Shin Department of Environmental Engineering Kyungpook National University

This study evaluated the application of a continuous-flow photocatalytic reactor for the control of two mobile-derived pollutants, methyl-tertiary butyl ether （MTBE） and naphthalene, present at in-vehicle levels. Variables tested for this study included the hydraulic diameter （HD）, stream flow rate （SFR）, relative humidity （RH）, and feeding type （FT）. The fixed parameters included contaminant concentration, ultraviolet light source, and the weight of TiO2. In all experimental conditions the adsorption process reached equilibrium within 30 to 180 min for the target compounds, and the outlet concentrations of the photocatalytic oxidation （PCO） reactor while operating reached a steady state within 60 to 180 min. The degradation of the target compounds was dependent on RH, HD, FT, or SFR. The PCO system exhibited high degradation （up to nearly 100% for certain conditions） and mineralization efficiencies of target compounds, suggesting that this system can effiectively be employed to improve indoor air quality. Moreover, it was confirmed that trichloroethylene at urban-ambient level also could enhance the degradation efficiency of naphthalene when applying the PCO technology inside vehicles.

关键词： in-vehicle level methyl-tertiary butyl ether naphthalene trichloroethylene

Tetradentate Pt(Ⅱ)complex as a singlet exciton sensitizing host for highly efficient green fluorescent organic light-emitting diodes

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Science China Materials 2024年第8期67卷 2618-2627页

作者： Unhyeok jo seung Chan Kim Chan Hee Ryu Kang Mun lee Jae-Min Kim Jun Yeob lee School of Chemical Engineering Sungkyunkwan University2066Seobu-roJangan-guSuwon-siGyeonggi-do 16419Republic of Korea Department of Chemistry Institute for Molecular Science and Fusion TechnologyKangwon National UniversityChuncheonGangwon 24341Republic of Korea Department of Advanced Materials Engineering Chung-Ang University4726Seodong-daeroDaedeok-myeonAnseong-siGyeonggi-do 17546Republic of Korea SKKU Advanced Institute of Nano Technology Sungkyunkwan University2066Seobu-roJangan-guSuwonGyeonggi 16419Republic of Korea SKKU Institute of Energy Science and Technology Sungkyunkwan University2066Seobu-roJangan-guSuwonGyeonggi 16419Republic of Korea

Efficient green fluorescent organic light-emitting diodes were designed with a phosphorescent metal complex as a singlet exciton sensitizing host(SESH)for achieving high efficiency and low efficiency roll-off through exciton and polaron *** Pt(Ⅱ)complex(Pt-Trz)possessing a tetradentate ligand with a bulky blocking group not only suppresses the severe formation of excimer or dimer itself but also transfers radiative excitons to fluorescent dopant *** SESH assisted fluorescence(SESHF)device with Pt-Trz as the host exhibits the maximum external quantum efficiency of 13.3%and a lower efficiency roll-off compared with exciplex host device which is a general approach for harvesting triplet *** exciton dynamics modeling unravels that the SESHF device effectively utilizes triplet excitons in the host by intersystem crossing and resonance energy transfer from the triplet state of the host to the singlet state of the terminal *** quenching rates of the SESHF device are reduced by 11 times for triplet-triplet annihilation and 1.8 times for tripletpolaron annihilation compared with the exciplex device,which demonstrates that Pt-Trz could be a platform to be used as an efficient host for fluorophores.

关键词： singlet annihilation polaron

Long-term performance of fiber-grid-reinforced asphalt overlay pavements: A case study of Korean national highways

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journal of Traffic and Transportation Engineering(English Edition) 2019年第4期6卷 366-382页

作者： jong-Hoon lee seung-Beom Baek Kang-Hoon lee jo-Soon Kim Jin-Hoon Jeong Department of Civil Engineering Inha UniversityIncheon 22212South Korea Civil&Environmental BG Doosan Engineering&ConstructionSeoul 06057South Korea Department of Infrastructure Safety Research Korea Institute of Civil Engineering and Building TechnologyGoyang-si 10223South Korea SN Construction Co. LtdDaejeon 34573South Korea

The objective of this study was to verify the effect of fiber grid reinforcement on the longterm performance of asphalt overlay pavements by performing field investigation, laboratory test, and finite element analysis. Crack, rutting, roughness, and other miscellaneous distresses of fiber-grid-reinforced overlay sections and ordinary overlay sections were compared. Pavement conditions of fiber grid overlay sections before and after the overlay were also compared. Cores were obtained from the fiber-grid-reinforced and ordinary sections to measure bonding shear strength between the intermediate and overlay *** energy, displacement after yield, and shear stiffness of the cores were also obtained by analyzing the test results. Finite element analysis was performed by using the test results to validate the effect of the fiber grid reinforcement on the long-term performance of asphalt overlay pavements. Rutting and fatigue cracking were predicted for three cases: 1) fiber grid was not used;2) glass fiber grid was used;and 3) carbon fiber grid was used. The cracking ratio of fiber-grid-reinforced sections was much smaller than that of ordinary sections. The results of field investigation, laboratory test, and finite element analysis showed that the fiber grid reinforcement improved the long-term performance of asphalt overlay pavements.

关键词： Asphalt pavement Fiber grid reinforcement Overlay pavement Finite element analysis Bonding shear strength

In situ observation of atomic movement in a ferroelectric film under an external electric field and stress

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Nano Research 2018年第7期11卷 3824-3832页

作者： Hyeon Jun lee Er-Jia Guo Taewon Min seung Hyun Hwang Su Yong lee Kathrin Dorr Jaekwang lee Ji Young jo School of Materials Science and Engineering Gwangju Institute of Science and Technology Gwangju 61005 Republic of Korea Quantum Condensed Matter Division Oak Ridge National Laboratory Oak Ridge TN 37830 USA Institute for Physics Martin-Luther-University Halle-Wittenberg Halle 06099 Germany Department of Physics Pusan National University Busan 46241 Republic of Korea Pohang AccelerotorLaboratory Pohang 37673 Republic of Korea

Atomic movement under application of external stimuli （i.e., electric field or mechanical stress） in oxide materials has not been observed due to a lack of experimental methods but has been well known to determine the electric polarization. Here, we investigated atomic movement arising from the ferroelectric response of BiFeO3 thin films under the effect of an electric field and stress in real time using a combination of switching spectroscop）6 time-resolved X-ray microdiffraction, and in situ stress engineering. Under an electric field applied to a BiFeO3 film, the hysteresis loop of the reflected X-ray intensity was found to result from the opposing directions of displaced atoms between the up and down polarization states. An additional shift of atoms arising from the linearly increased dielectric component of the polarization in BiFeO3 was confirmed through gradual reduction of the diffracted X-ray intensity. The electric-field- induced displacement of oxygen atoms was found to be larger than that of Fe atom for both ferroelectric switching and increase of the polarization. The effect of external stress on the BiFeO3 thin film, which was controlled by applying an electric field to the highly piezoelectric substrate, showed smaller atomic shifts than for the case of applying an electric field to the film, despite the similar tetragonality.

关键词： in situ measurement atomic displacementunder electric field time-resolved X-ray microdiffraction ferroelectrics in situ strain engineering

A new damage quantification approach for shear-wall buildings using ambient vibration data

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Frontiers of Structural and Civil Engineering 2015年第1期9卷 17-25页

作者： seung-Hun SUNG Hyung-jo JUNG Department of Civil and Environmental Engineering Korea Advanced Institute of Science and Technology Daejeon 305- 701 Korea

This paper presents a new approach to estimate damage seventy tor slaear-wall DUlltllngs using alagona~ terms of a modal flexibility matrix estimated from dynamic properties. This study aims to provide a fundamental concept for quantifying the damage of realistic buildings by investigating an idealized shear-wall building. Numerical studies were performed on a 5-story shear-wall building model to validate the applicability of the presented approach, using two damage patterns. With the numerical simulations, the proposed approach accurately determined the damage ratio of the specimens. Experiments were also conducted on a 5-story shear-wall building model for which the system parameters were almost the same as those in numerical simulations. The estimated damage-quantification results from the experimental validations demonstrated that the performance of the presented method for shear-wall buildings was both suitable and accurate.

关键词： damage identification modal flexibility damage quantification shear-wall buildings

Materials and extracellular matrix rigidity highlighted in tissue damages and diseases:Implication for biomaterials design and therapeutic targets

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Bioactive Materials 2023年第2期20卷 381-403页

作者： Jae Hee Park seung Bin jo Jung-Hwan lee Hae-Hyoung lee jonathan CKnowles Hae-Won Kim Institute of Tissue Regeneration Engineering(ITREN) Dankook UniversityCheonan31116Republic of Korea Department of Nanobiomedical Science and BK21 NBM Global Research Center for Regenerative Medicine Dankook UniversityCheonan31116Republic of Korea Department of Biomaterials Science College of DentistryDankook UniversityCheonan31116Republic of Korea Cell&Matter Institute Dankook UniversityCheonan31116Republic of Korea Mechanobiology Dental Medicine Research Center Dankook UniversityCheonan31116Republic of Korea UCL Eastman-Korea Dental Medicine Innovation Centre Dankook UniversityCheonan31116Republic of Korea Division of Biomaterials and Tissue Engineering UCL Eastman Dental InstituteUniversity College LondonRoyal Free HospitalRowland Hill StreetLondonNW32PFUnited Kingdom

Rigidity(or stiffness)of materials and extracellular matrix has proven to be one of the most significant extracellular physicochemical cues that can control diverse cell behaviors,such as contractility,motility,and spreading,and the resultant pathophysiological *** 2D materials engineered with tunable rigidity have enabled researchers to elucidate the roles of matrix biophysical cues in diverse cellular events,including migration,lineage specification,and mechanical ***,the recent findings accumulated under 3D environments with viscoelastic and remodeling properties pointed to the importance of dynamically changing rigidity in cell fate control,tissue repair,and disease ***,here we aim to highlight the works related with material/matrix-rigidity-mediated cell and tissue behaviors,with a brief outlook into the studies on the effects of material/matrix rigidity on cell behaviors in 2D systems,further discussion of the events and considerations in tissue-mimicking 3D conditions,and then examination of the in vivo findings that concern material/matrix *** current discussion will help understand the material/matrix-rigidity-mediated biological phenomena and further leverage the concepts to find therapeutic targets and to design implantable materials for the treatment of damaged and diseased tissues.

关键词： Matrix rigidity Biophysical cue Cell and tissue engineering 3D biomaterials conditions Therapeutic targets