A5050749052- Ferroelectric and Piezoelectric Materials
- Multiferroics and related materials
- Microwave Dielectric Ceramics Synthesis
- Catalytic Processes in Materials Science
- Plasma Applications and Diagnostics
- Acoustic Wave Resonator Technologies
- Dielectric materials and actuators
- Gas Sensing Nanomaterials and Sensors
- Photonic and Optical Devices
- Photonic Crystals and Applications
- Piezoelectric Actuators and Control
- X-ray Diffraction in Crystallography
- Industrial Gas Emission Control
- Microwave-Assisted Synthesis and Applications
- Phase-change materials and chalcogenides
- Dental materials and restorations
- Ginger and Zingiberaceae research
- Quasicrystal Structures and Properties
- Ultrasonics and Acoustic Wave Propagation
- Recycling and Waste Management Techniques
- Marine Toxins and Detection Methods
- Additive Manufacturing and 3D Printing Technologies
- Grouting, Rheology, and Soil Mechanics
- Thin-Film Transistor Technologies
- Phytochemistry and Biological Activities
Yonsei University
2025
Beihang University
2025
Seoul National University
2024
Samsung (South Korea)
2020-2023
Osaka Prefecture University
2021
University of Ulsan
2012-2017
Tokyo Institute of Technology
2000-2014
King University
2011
Peking University
2011
Daelim University College
2009
Dielectric, ferroelectric, piezoelectric, and strain properties of lead-free Sn-doped Bi1/2(Na0.82K0.18)1/2TiO3 (BNKT) were investigated. A crossover from a nonergodic relaxor to an ergodic state at room temperature, accompanied by giant electric-field-induced strain, was observed 5 at. % Sn doping. Switching dynamics monitored during bipolar poling cycle manifested that the originates incipient piezoelectricity. When doping level reached 8 %, BNKT exhibited electrostrictive behavior with...
Lead-free 0.96[Bi1/2(Na0.84K0.16)1/2(Ti(1−x)Nbx)O3]–0.04SrTiO3 (BNKTN–ST, with x = 0–0.030) ceramics were synthesized by a conventional solid-state reaction technique. Polarization and strain hysteresis loops indicated significant disruption of ferroelectric order accompanied an enhanced field-induced (S 0.438%) high normalized Smax/Emax 876 pm/V at 5 kV/mm. Their reproducibility was confirmed the fabrication 10-layered stack-type multilayer actuator, which demonstrated 720 pm/V.
Abstract Thermoelectric materials enable solid‐state cooling, which has drawn significant attention in the electronics industry. Current thermoelectric cooling devices rely on advanced Bi 2 Te 3 alloys. However, scarcity of element raises price and limits their widespread use. Therefore, developing high‐performance, low‐cost is a key focus field. In this work, high‐performance n‐type PbSe crystal developed through lattice plainification physical vapor deposition. Adding trace amounts Sn...
To improve the strain properties of Bi-based lead-free ceramics at lower electric fields, ferroelectric 0.82(Bi1/2Na1/2)TiO3-0.18(Bi1/2K1/2)TiO3 (BNKT) seed particles were embedded in Bi0.5(Na0.385K0.09Li0.025)(Ti0.975Ta0.025)O3 (BNKLTT) exhibiting relaxor behaviour using a conventional solid-state reaction. The unipolar versus field hysteresis loops BNKT-BNKLTT composites resulted maximum Smax/Emax 761 pm/V 4 kV/mm when 30 wt.% BNKT added, which was higher than that single or phase.
The relationship between the propagation loss and roughness on multi-layered Si waveguides fabricated up to a 3<sup>rd</sup> layer was investigated. By reducing surface sidewall of waveguides, low 3.7 dB/cm for 3 a-Si:H demonstrated. Furthermore, vertical coupling multilayer demonstrated by use grating-type coupler. A efficiency 22% obtained 10 pairs gratings with period 640 nm, even distance 1μm.
Several exhaust gas regulations are being implemented to prevent the hazardous emissions of volatile organic compounds (VOCs) and particulate matter (PM) from paint print factories. The VOCs generate photochemical oxidants suspended PM, such as PM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2.5</sub> , which has become a global environmental problem. We evaluate catalytic nonthermal plasma (NTP) technique for controlling emission VOCs....
Nitrogen oxides ( NO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> ), sulfur SO and particulate matter (PM) emitted by diesel engines, thermal power generation plants, various industrial establishments have had unfavorable effects on the environment globally. Therefore, it is necessary to install aftertreatment systems such combustors because emissions cannot be treated for combustion improvement only. To establish /SO , nanoparticle...
검은생강은 항산화 및 항염증 활성과 관련된 다양한 생물학적 기능성을 제공한다. 본 연구에서는 효과를 통한 지질대사 조절에 주안점을 두고 고지방식이로 비만을 유도한 C57BL/6J 마우스를 이용하여 KPE의 지방감소 연구하였다. KPE를 50, 100 200 ㎎/㎏/day 농도로 경구 투여하였을 때, 지방 부피와 무게, 지방구의 크기가 감소되었다. KPE는 아디포넥틴, PPARα, AMPK, cAMP, HSL, ATGL의 발현을 증가시켜 지방분해를 촉진하였으며, ACC와 FAS의 감소시켜 지방합성을 억제하였다. 또한, 효소의 활성을 증가시키고, 염증 반응 인자들의 농도를 감소시켰다. 따라서, 비만 완화를 위한 기능성 소재로 활용될 수 있을 것으로 기대된다.
Hydration reaction of a calcium sulfoaluminate-type expansive additive (CSA)-Alite system was investigate at quantitative viewpoint. Free lime and anhydrite rapidly reacted initial period but hauyne did slowly. In special, early days, the showed extremely high ratio. As formed hydrates, hydroxide ettringite could be identified. And, from materials balance hydration, presence large amount gel presumed. SO3 contents in value within 1 period, after reducing to half by 3d it nearly constant...
We investigated the effect of Ta doping on dielectric and piezoelectric properties lead-free (K0.5Na0.5)NbO3 ceramics prepared using a conventional ceramic processing. X-ray diffraction analysis revealed that was perfectly substituted into Nb-sites in range 0 to 20 at%. As content KNN increased, sinterability significantly degraded while enhanced constant d33, planar mode coupling coefficient (kp), electromechanical quality factor (Qm). The highest values for kp, Qm found be 156 pC/N, 0.37,...
A bolt-clamped ultrasonic viscometer was designed and fabricated using a pair of ring-shaped piezoelectric ceramic resonators. For its compactness low operation frequencies, simulation resonators carried out an ATILA program. Ring-shaped <TEX>$0.05Pb(Mn_{1/3}Sb_{2/3})O_3-0.95Pb(Zr_{0.475}Ti_{0.525})O_3$</TEX> ceramics were prepared by conventional processing, which then clamped with metal caps. The sensor module small volume less than 1 <TEX>$cm^3$</TEX> frequency as 26.5 kHz showed good...
Volatile organic compounds (VOCs) and particulate matter (PM) emitted from factories in the painting printing industries, various exhaust gas regulations have been implemented. VOCs are cause of photochemical oxidants suspended PM such as <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2.5</inf> , which has become a global environmental problem. As one solution technologies, catalysis nonthermal plasma (NTP) techniques studied control methods....
We investigated the effect of excess CuO on sintering behavior, ferroelectric, and piezoelectric properties lead-free <TEX>$Bi_{0.5}(Na_{0.82}K_{0.18})_{0.5}TiO_3$</TEX> (BNKT) ceramics. The addition was found to greatly contribute densification grain growth, however, over 3 mol% precipitated at boundaries after sintering. BNKT with 1~2 in sintered <TEX>$975^{\circ}C$</TEX> showed comparable those unmodified <TEX>$1,175^{\circ}C$</TEX>. These results seem meaningful for its application low...
An optical isolator is fabricated with an amorphous silicon waveguide core deposited using a plasma-enhanced chemical-vapor-deposition technique on magneto-optical garnet Ce:YIG. isolation ratio of 17 dB demonstrated.