Jong Pil Kim

Molecular cloning and characterization of mouse cardiac triadin isoforms.

Triadin is a ryanodine receptor and calsequestrin binding protein located in junctional sarcoplasmic reticulum of striated muscles. In the present study, mouse cardiac triadin cDNAs have been identified by cDNA library screening and RT-PCR. The deduced aa sequences show that the three isoforms consist of 277, 293 and 305 aa giving rise to the molecular weights of approximately 31,414, 33,066, and 34,328, respectively. The isoforms have identical 262 aa N-terminal sequences, whereas they have distinct C-terminal sequences. Northern blot analysis using a cDNA probe representing the N-terminal common region of triadin revealed that the mouse triadins were present both in heart and skeletal muscles. The estimated sizes of the transcripts were approximately 1.3, 4.3 and 5 kb in heart and 5, 5.5 and 7 kb in skeletal muscle. Endo H treatment and Western blot analysis of isolated mouse cardiac sarcoplasmic reticulum and in vitro translation products indicate that there are three distinct mouse cardiac triadin isoforms having molecular weights of 35, 35.5 and 40 kDa. We termed those three isoforms as mouse cardiac triadin 1, mouse cardiac triadin 2 and mouse cardiac triadin 3.

Removal of Heavy Metal Ions by using Calcium Carbonate Extracted from Starfish Treated by Protease and Amylase

CaCO3 extracted from starfish by using the commercial protein lyase having α-amylase, β-amylase, and protease is applied to remove heavy metal ions. The extracted CaCO3 shows excellent characteristics in removing heavy metal ions such as Cu 2+ , Cd 2+ , Pb 2+ , and Cr 6+ compared with conventional materials such as crab shells, sawdust, and activated carbon except for removing Zn 2+ . SEM images reveal that the extracted CaCO3 has a good morphology and porosity. We characterize the removal efficiencies of the extracted CaCO3 for the heavy metal ions according to the concentrations, pH, temperatures, and conditions of empty bed contact times.

A study of the correlation between hydrogen content and magnetism in ZnCoO

Through the hydrogen treatment of Co-doped ZnO (ZnCoO), the Co-H-Co complex manifests the magnetization mediated by H. The increase in hydrogen content causes an increase in the number of Co-H-Co units, which can be controlled by the hydrogen treatment conditions. The 15 mol. % ZnCoO showed a proportional tendency between the hydrogen content and remnant magnetization under different conditions of rf power for the plasma treatment. The 20 mol. % sample showed deviation from the proportional tendency by the existing CoO phase before hydrogen injection and the formation of the Co metal phase after hydrogen injection. If one ensures the enhanced solubility limit of Co in ZnO and uses the correlation between the hydrogen content and magnetization below the solubility limit, this magnetic tool may be a good method for the measurement of the hydrogen content.

Electronic defect characteristics of Ferroelectric Sr0.25Ba0.75Nb2O6 thin films

Abstract Ferroelectric Sr0.25Ba0.75Nb2O6 (SBN) thin films were successfully grown on p-type (100) Si and (111) Pt substrates by the rf magnetron sputtering method. The crystallinity of the films was confirmed using x-ray diffraction pattern. The memory window of Au/SBN/Si structure was measured 1.3 V from the C-V curve when the gate voltage was 6V.

Optical properties and Surface analysis of lithium incorporated Y2O3:Eu3+ ceramic phosphors

The influence of lithium doping concentration on the crystallization, the surface morphology, and the luminescent properties of Y1.92O3:Eu0.08 ceramic phosphors were investigated. The crystallinity, the surface morphology, and the photoluminescence (PL) of ceramics depended highly on the Li-doping concentrations. The relationship between the crystalline and morphological structures and the luminescent properties was studied, and Li-doping was found to affect not only the enhanced crystallinity but also the luminescent brightness of Y1.92O3:Eu0.08 ceramics. In particular, the incorporation of Li ion into the Y2O3 lattice could induce remarkable increase in the PL intensity. The strongest emission intensity was observed with Y1.68Li0.24O3:Eu0.08 ceramics whose brightness was increased by a factor of 6.5 in comparison with that of Y1.92O3:Eu0.08 ceramics.

Growth and Physical Characterization of La-Doped Bi 4 Ti 3 O 12 Crystals

The crystals of La-doped Bi 4 Ti 3 O 12 were grown by a conventional flux growth method using Bi 2 O 3 , TiO 2 and La 2 O 3 . The quantitative analysis of x-ray photoelectron spectra and change of band gap make an estimate of La sites in the La doped Bi 4 Ti 3 O 12 crystals. All of the La ions doped in the Bi 4 Ti 3 O 12 crystals are well substituted with Bi ions. The remanent polarization, P r and the coercive field, E c were 3.2, 5.2 and 0.3 w C/cm 2 , and 5.6, 7.6 and 0.6 kV/cm for Bi 4.3 Ti 3 O 12.4 , Bi 3.65 La 0.47 Ti 3 O 12.17 and Bi 2.76 La 1.67 Ti 3 O 12.65 crystals, respectively. However, Bi 2.76 La 1.67 Ti 3 O 12.65 crystal seems to be not saturated.

The effect of hydrogen on switching properties of ferroelectric PZT thin films

Abstract To investigate the hydrogen-enhanced degradation of the ferroelectric PZT capacitor, the switching current produced by the reversal of domains in ferroelectric PZT thin film memories is analyzed as a function of H2 gas annealing time using the Avrami theory. The switching time ts and the switchable polarization of the PZT films decrease with H2 gas annealing. The H2 gas annealing increase the concentration of defects, such as an oxygen vacancy, a lead vacancy, and a OH ions, on the surface of PZT film or inside PZT film. These defects lead to reduce the switching time ts and to increase the activation field α. The polarization of ferroelectric PZT film is reduced and pinned by OH bond during the H2 gas annealing.

Growth and Characterization of Ca3(VO4)2Single Crystal

The Ca 3 (VO 4 ) 2 single crystal was grown by the Czochralski method. The crystal was pulled with 1 mm/hr and was rotated with 10 rpm for the optimum crystal growth condition. The thermal annealing of as-grown Ca 3 (VO 4 ) 2 crystal was performed at 500°C for 24 hours. The Laue and conoscopic image techniques were used to determine the crystallographic axes of Ca 3 (VO 4 ) 2 . The results showed a negative uniaxial indicatrix. The spectra of Ca2p, V2p, and O1s core-level data in Ca 3 (VO 4 ) 2 single crystals were investigated by X-ray photoelectron spectroscopy.

Study of High-k Dielectric Insulation Layers for Organic TFT and Characteristics of TFT

Amorphous SrBi 2 Nb 2 O 9 films were deposited on ITO/PET by rf magnetron sputtering to investigate their potential as a gate dielectric in organic thin film transistors (OTFTs). The deposition was performed at room temperature using SrBi 2 Nb 2 O 9 target. Achieved SrBi 2 Nb 2 O 9 films have higher capacitance values than thermally grown SiO 2 as characterized by capacitance-frequency measurements. It is also found from current-voltage and roughness measurements that the leakage current and the surface roughness can be least when the films are deposited at room temperature. These room temperature processes are promising for applications to the gate dielectircs of OTFTs. OTFT characteristics were obtained, including carrier mobility as large as 0.03 cm 2 /Vs, on/off current ratio as 10 3 for organic transistor fabricated on PET.

Crystallization and Conduction Mechanisms on Amorphous PbTiO3

Glass system of xPbTiO3–(100-x)B2O3 (x = 50, 70, 80) was produced by twin-roller quenching method. Glass transition temperatures were 541.3°C, 440.0°C, and 467.8°C for the x =80, 70, and 50, respectively with heating rate of 10°C/min. Crystallization temperatures(activation energies) were 517.5°C (4.10 eV), 526.5°C (3.72 eV), 547.2°C (3.79 eV), and 557.5°C (3.97 eV), for the samples of x=80, x=70, 1st crystallization of x=50, and 2nd crystallization of x=50, respectively. It was revealed that this sample crystallized two-dimensionally analyzed by modified Ozawa method. From the X-ray diffraction experiments of heat-treated samples of x=70, the PbTiO3 crystalline did not form a tetragonal phase right after crystallization temperature but a cubic phase. By further annealing the PbTiO3 crystalline became a tetragonal ferroelectrics. From the temperature- and frequency-dependence of dielectric constants, it was revealed that two conduction mechanisms are responsible for the dielectric response, and the transition frequency was thermally activated. The activation energies above and below the crystallization temperature are 1.1 and 0.7 eV, respectively.