A5087328849- Ferroelectric and Piezoelectric Materials
- Multiferroics and related materials
- Acoustic Wave Resonator Technologies
- Microwave Dielectric Ceramics Synthesis
- Dielectric materials and actuators
- Perovskite Materials and Applications
- Electronic and Structural Properties of Oxides
- Solid-state spectroscopy and crystallography
- Advanced Sensor and Energy Harvesting Materials
- Protein Hydrolysis and Bioactive Peptides
- Conducting polymers and applications
- Dielectric properties of ceramics
- Magnetic and transport properties of perovskites and related materials
- Electrical and Thermal Properties of Materials
- Chalcogenide Semiconductor Thin Films
- Phytoestrogen effects and research
- Advanced Condensed Matter Physics
- Photorefractive and Nonlinear Optics
- Advanced Photocatalysis Techniques
- Thermal Expansion and Ionic Conductivity
- Biochemical effects in animals
- Innovative Energy Harvesting Technologies
- 2D Materials and Applications
- Graphene research and applications
- Advancements in Battery Materials
University of Ulsan
2016-2025
EuBiologics (South Korea)
2024
Kyung Hee University
2021
Korea Basic Science Institute
2008-2018
Ulsan National Institute of Science and Technology
2018
University of Science and Technology Bannu
2018
Islamia College University
2018
Ulsan College
2014-2016
Ulsan University Hospital
2003-2015
Korea Electronics Technology Institute
2010
Lead-free piezoceramics aiming at replacing the market-dominant lead-based ones have been extensively searched for more than a decade worldwide. Some noteworthy outcomes such as advent of commercial products certain applications reported, but goal, i.e., invention lead-free piezocermic, performance which is equivalent or even superior to that PZT-based piezoceramics, does not seem be fulfilled yet. Nevertheless, academic effort already seems culminated, waiting guideline future research...
Robust nanogenerator based on poly( tert -butyl acrylate)–grafted PVDF copolymers via dielectric constant control is demonstrated.
It has been reported that soybean peptide fractions isolated from Korean fermented paste exert angiotensin I converting enzyme (ACE) inhibitory activity in vitro. In this study, further purification and identification of the most active fraction inhibiting ACE were performed, its antihypertensive vivo was confirmed. Subsequently, a novel by preparative HPLC. The amino acid sequence identified as His-His-Leu (HHL) Edman degradation. IC50 value HHL for 2.2 μg/mL Moreover, synthetic tripeptide...
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 piezoelectric ceramics, 0.96[{Bi 0.5 (Na 0.84 K 0.16 ) } 1− x Li (Ti y Nb )O 3 ]–0.04SrTiO (BNKLiTN–ST) with , = 0–0.030, were synthesized by solid‐state reaction method. X‐ray diffraction patterns indicated that and successfully diffused into the BNKT – ST lattice formed a pure perovskite structure x, ≤ 0.025. Increasing contents ( 0.020) induced phase transformation from coexistent rhombohedral–tetragonal phases for ceramics to pseudocubic phase, resulting in degradation of...
In spite of extremely high piezoelectric and pyroelectric coefficients, there are few reports on flexible ferroelectric perovskite film based nanogenerators (NGs). Here, we report the successful growth a Pb(Zr0.52Ti0.48)O3 (PZT) its application to hybrid piezoelectric-pyroelectric NG. A highly Ni–Cr metal foil substrate with conductive LaNiO3 bottom electrode enables PZT having (140 pC/N) (50 nC/cm2K) coefficients at room temperature. The PZT-based NG effectively scavenges mechanical...
We have fabricated K0.5Na0.5NbO3 (KNN) thin films on Pt substrates by a chemical solution deposition method and investigated the effect of K Na excess (0–30 mol%) ferroelectric piezoelectric properties KNN film. It was found that with increasing in precursor from 0 to 30 mol%, leakage current were strongly affected. film synthesized using 20 mol% exhibited low density well saturated P–E hysteresis loops. Moreover, optimized had good fatigue resistance constant 40 pm V−1, which is comparable...
Lead‐free piezoelectric (1– x )( Bi 0.5 (Na 0.75 K 0.25 ) TiO 3 )‐ BiAlO ( BNKT25 ‐ BA, = 0–0.100) ceramics were synthesized using a conventional solid‐state reaction method. The effect of BA addition into the was investigated by X‐ray diffraction, dielectric and ferroelectric characterizations, electric field‐induced strain. diffraction revealed phase transition from tetragonal to pseudocubic at 0.050. As content increased, maximum constant as well depolarization temperature T d decreased....
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.
In this letter, the composition and electric field dependent strain behavior of (1 − x)Bi0.5(Na0.78K0.22)0.5TiO3-xBi(Mg0.5Ti0.5)O3 (BNKT-BMT) were investigated to develop lead-free piezoelectric materials with a large response at low driving for actuator applications. A 0.35% (Smax/Emax = 636 pm/V) an applied 55 kV/cm was obtained 4 mol. % BMT. particular, required deliver strains reduced level that revealed not only Smax/Emax 542 pm/V as 35 kV/cm, but also remarkably suppressed hysteresis.
Piezoceramics 0.99[( Bi 0.5 Na 0.4 K 0.1 ) 1− x La TiO 3 ]−0.01[ Ba 0.7 Sr 0.3 ] ( BNKT – BST , = 0–0.030) were synthesized using a conventional solid‐state reaction method. X‐ray diffraction revealed phase transition from tetragonal to cubic at ≥ 0.005. The maximum dielectric constant as well the depolarization temperature T d decreased with increasing content. addition interrupted polarization and strain hysteresis loops demonstrates that ferroelectric order of BNKT–BST ceramics lead...
In this study, a ternary solid solution (0.935 −<italic>x</italic>)BNT–0.065BT–<italic>x</italic>Bi(Mn<sub>0.5</sub>Ti<sub>0.5</sub>)O<sub>3</sub>(BNT–BT–BMnT;<italic>x</italic>= 0–0.030) was designed and fabricated by means of conventional fabrication process.
Boosting dielectric permittivity representing electrical polarizability of materials has been considered a keystone for achieving scientific breakthroughs as well technological advances in various multifunctional devices. Here, we demonstrate sizable enhancements low-frequency responses oxygen-deficient oxide ceramics through specific treatments under humid environments. Ultrahigh (~5.2 × 10 6 at 1 Hz) is achieved by hydrogenation, when Ni-substituted BaTiO 3 are exposed to high humidity....
Ferroelectric Na0.52K0.48NbO3 (NKN) thin film on Pt/Ti/SiO2/Si substrate was prepared using the radio frequency magnetron sputtering method. The single phase and grain morphologies of NKN were confirmed by x-ray diffraction atomic force microscopy analysis, respectively. remnant polarization Pr coercive electric field Ec 22.5 μC/cm2 90 kV/cm, displayed low dielectric dispersion in temperature range 25–500 °C. leakage current density 3.0×10−7 A/cm2 at 100 kV/cm. piezoelectric constant d33...
Lead-free piezoelectric Bi 0.5 (Na 0.78 K 0.22 ) (Ti 1- x Hf )O 3 ceramics (abbreviated as BNKTH-100 , =0–0.05) were prepared by the conventional solid-state reaction method. The effects of substitution on crystal structure and electromechanical properties investigated. X-ray diffraction patterns revealed a single-phase perovskite with no evidence secondary phases. temperature-dependent dielectric curves found to broaden increasing concentration. electric-field-induced strain increased up...