• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.06a
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• pp.139-142
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• 1998

PLZT thin films were fabricated with different Zr/Ti ratios by pulsed laser deposition. PLZT films deposited on Pt/Ti/SiO$_2$/Si substrate. This PLZT thin films of 5000${\AA}$. thickness were crystallized at 600$^{\circ}C$, 200 mTorr O$_2$ press. 2/55/45 PLZT thin film showed a maximum dielectric constant value of $\varepsilon$$\_$r/=1500, and dielectric loss was 0.O$_3$. At 2/70/30 PLZT thin film, Coercive field and remnant polarization was respectively 19[kV/cm], 8[${\mu}$C/$\textrm{cm}^2$].

• BMB Reports
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• v.56 no.6
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• pp.359-364
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• 2023

KAI1/CD82, a membrane tetraspanin protein, can prevent various cancers and retinal disorders through its anti-angiogenic and anti-metastatic capacity. However, little is known about its anti-inflammatory effect and molecular mechanism. Therefore, the present study aimed to inLPSvestigate effect of a recombinant protein of the large extracellular domain of human KAI1 (Gly 111-Leu 228, rhKAI1) on lipopolysaccharides (LPS)-stimulated RAW264.7 macrophage-like cells and mouse bone marrow-derived macrophages (BMDM) and to identify its underlying mechanism. Our data showed that rhKAI1 suppressed expression levels of classically macrophages (M1) phenotype-related surface markers F4/80+CD86+ in LPS-stimulated BMDM and RAW264.7 cells. In addition, LPS markedly increased mRNA expression and release levels of pro-inflammatory cytokines and mediators such as interleukin (IL)-1β, IL-6, tumor necrosis factor-α, cyclooxygenase-2, nitric oxide and prostaglandin E2, whereas these increases were substantially down-regulated by rhKAI1. Furthermore, LPS strongly increased expression of NF-κB p65 in the nuclei and phosphorylation of ERK, JNK, and p38 MAPK. However, nuclear translocation of NF-κB p65 and phosphorylation of JNK were greatly reversed in the presence of rhKAI1. Especially, rhKAI1 markedly suppressed expression of toll-like receptor (TLR4) and prevented binding of LPS with TLR4 through molecular docking predict analysis. Importantly, Glu 214 of rhKAI1 residue strongly interacted with Lys 360 of TLR4 residue, with a binding distance of 2.9 Å. Taken together, these findings suggest that rhKAI1 has an anti-inflammatory effect on LPS-polarized macrophages by interacting with TLR4 and down-regulating the JNK/NF-κB signaling pathway.

• Journal of the Korean Ceramic Society
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• v.34 no.8
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• pp.897-907
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• 1997

Thin films of Bi4-xSmxTi3O12(0$\leq$x$\leq$2) were prepared on Pt/Ti/SiO2/Si(100) at $700^{\circ}C$ using spin-coating with sols derived from Bi-Sm-Ti complex alkoxides. From X-ray diffraction analysis, it was observed that Sm-substituted phases resembled ferroelectric Bi4Ti3O12 in structure. Variations of their lattice parameters depending on the amount of Sm-substitution showed that an anomalous structural distortion might exist at x=1. The grain sizes of the thin films decreased from 0.115 ${\mu}{\textrm}{m}$ to 0.078${\mu}{\textrm}{m}$ with increasing the amount of Sm-substitution. The dielectric constants and the remanent polarizations of the thin films decreased with increasing the amount of the Sm-substitution, which were related to decrease of the stereo-active Bi3+ ion contributing to polarization. However, these values were exceptionally high at x=1, compared to those of the other substituted phases. Such an anomaly suggests that the phase of x=1 has 1:1 chemical ordering between Sm and Bi in structure. The thin films of all compositions except x=2 showed ferroelectricity. The thin film of x=2 was paraelectric, whose grains were too fine to exhibit ferroelectricity.

• Electrical & Electronic Materials
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• v.9 no.3
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• pp.251-258
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• 1996

Sol-Gel derived ferroelectric Pb(Z $r_{0.52}$ $Ti_{0.48}$) $O_{3}$ thin films have been fabricated on Pt/Ti/ $SiO_{2}$/Si substrate. Two kinds of fast annealing methods, F-I (six times of intermediate and final annealing) and F-II(one final annealing after six times of intermediate annealing) were used for preparation of multi-coated PZT thin films. As the annealing temperature was increased, high capacitance could be obtained, for instance, 2700.angs.-thick PZT thin film annealed at 680.deg. C had a capacitance value of approximately 20nF at 1kHz. In addition, it is found that the dielectric constant is a function of the perovskite phase fraction. In case of F-I method, PZT thin film had a remanent polarization(Pr) of 8-15.mu.C/c $m^{2}$ and a coercive field( $E_{c}$) of 35-44kV/cm according to annealing temperature, whereas PZT film fabricated by F-II method had as high as 24-25.mu.C/c $m^{2}$ and 48-59kV/cm, respectively. As a result of measuring Curie temperature, PZT thin film had a range of 460-480.deg. C by F-I method and more or less higher range of 525-530.deg. C by F-II method, which implied that different microstructures could cause the different Curie temperature. Through I-V measurement, leakage current of PZT thin film fabricated by F-I and F-II methods was 64nA/c $m^{2}$ and 2.2.mu.A/c $m^{2}$ in the electric field of 100kV/cm, respectively.y.y.y.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11b
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• pp.545-549
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• 2001

We have produced electrolyte solution out of 1.15M $LiPF_6$ EC/EMC/DEC/PC(30/55/10/5 by vol%) as a reference, and at the same time, performed basic physical property test using a single solvent of 1.15M $LiPF_6$ DEC, DMC, EMC and a 2 component electrolyte solution of 1.15M $LiPF_6$ EC/DEC(1/2 by vol%) and PC/DEC(1/2 by vol%). Cyclic Voltammetry Analysis showed that, compared to existing carbonate organic solvent, the addition of DEC,DMC and EMC brought the de-decomposition peak of salt anion of $PF_6$ and the solvent at lower oxidization potential of 2.3V, 0.7V and 2.1V(vs. $Li/Li^+$). In addition, a kinetics current peak, in which intercalation of Lt is proceeded at 750mV, 450mV(vs. $Li/Li^+$), was confirmed. These findings suggest that the DEC solvent decomposition occurred at an electric potential lower than that of oxidization of existing carbonate organic solvent. Through the impedance analysis, we checked electric charge transfer resistance($R_{ct}$) according to the electric potential of $Li^+$ intercalation at 750mV(vs. $Li/Li^+$), which was the same as the resistance ($R_f$) and cyclic voltammetry of SEI film that was formed at Reference. By doing so, we found that the significant decrease of polarization resistance($R_p$) when Reference was played a part in the formation of compact SEI layer at the initial decomposition reaction.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.1
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• pp.44.1-44.1
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• 2015

We present joint constraints on the number of effective neutrino species $N_{eff}$ and the sum of neutrino masses ${\Sigma}m_{\nu}$, based on a technique which exploits the full information contained in the one-dimensional Lyman-${\alpha}$ forest flux power spectrum, complemented by additional cosmological probes. In particular, we obtain $N_{eff}=2.91{\pm}0.22$ (95% CL) and ${\Sigma}m_{\nu}$ < 0.15 eV (95% CL) when we combine BOSS Lyman-${\alpha}$ forest data with CMB (Planck+ACT+SPT+WMAP polarization) measurements, and $N_{eff}=2.88{\pm}0.20$ (95% CL) and ${Sigma}m_{\nu}$ < 0.14 eV (95% CL) when we further add baryon acoustic oscillations. Our results tend to favor the normal hierarchy scenario for the masses of the active neutrino species, provide strong evidence for the Cosmic Neutrino Background from $N_{eff}{\approx}3$($N_{eff}=0$ is rejected at more than $14{\sigma}$), and rule out the possibility of a sterile neutrino thermalized with active neutrinos (i.e., $N_{eff}=4$) - or more generally any decoupled relativistic relic with $${\Delta}N_{eff}{\sim_=}1$$ - at a significance of over $5{\sigma}$, the strongest bound to date, implying that there is no need for exotic neutrino physics in the concordance ${\Lambda}CDM$ model.

• Journal of IKEEE
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• v.22 no.1
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• pp.209-212
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• 2018

In this work, we developed P(VDF-TrFE) organic/ferroelectric material based metal-ferroelectric-metal (MFM) capacitors in order to improve the switching characteristics of gallium nitride (GaN) heterojunction field-effect transistors (HFET). The 27 nm-thick P(VDF-TrFE) MFM capacitors exhibited about 60 ~ 96 pF capacitance with a polarization density of $6{\mu}C/cm^2$ at 4 MV/cm. When the MFM capacitor was connected in series with the gate electrode of GaN HFET, the subthreshold slope decreased from 104 to 82 mV/dec.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.35-36
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• 2006

The influence of the concentration of precursor solution and the number of solution coatings on the densification of the Pb($Zr_xTi_{1-x}$)$O_3$(PZT) thick films was studied. PZT powder and PZT precursor solution were prepared by sol-gel method and PZT thick films were fabricated by the screen-printing method on the alumina substrates. The powder and solution of composition were PZT(70/30) and PZT(30/70), respectively. The coating and drying procedure was repeated 4 times. And then the PZT precursor solution was spin-coated on the PZT thick films. A concentration of a coating solution was 0.5 to 2.0 mol/L[M] and the number of coating was repeated from 0 to 6. The relative dielectric constant of the PZT thick film was increased with increasing the number of solution coatings and the thick films with 15M, 6-time coated showed the 698. The remanent polarization of the 1.5M, 6-time coated PZT thick films was 38.3 ${\mu}C/cm^2$.

• Journal of the Korean institute of surface engineering
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• v.34 no.3
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• pp.195-205
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• 2001

The surface characteristics of Ti/TiN films coated on sintered stainless steels (SSS) by electron beam physical vapour deposition (EB-PVD) were investigated. Stainless steel compacts containing 2, 4, and 10wt%Cu were prepared by the electroless Cu-plating method, which results in increased homogenization in the alloying powder. The specimens were coated with Ti and TiN with a 1.0$\mu\textrm{m}$ thickness respectively by EB-PVD. The microstructures were investigated using scanning electron microscopy (SEM). The corrosion behaviors were investigated using a potentiosat in 0.1 M $H_2$$SO_4$, and 0.1M HCl solutions and the corrosion surface was observed using SEM and XPS. The Ti coated specimens showed rough surface compared to Ti/TiN coated specimens. Ti and Ti/TiN coated SSS revealed a higher corrosion and pitting potential from anodic polarization curves than that of Ti and Ti/TiN uncoated SSS. In addition, Ti/TiN coated SSS containing 10wt% Cu exhibited good resistance to pitting corrosion due to the formation of a dense film on the surface and the decrease in interconnected porosity by electroless coated Cu.

• Journal of the Korean institute of surface engineering
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• v.38 no.6
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• pp.241-247
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• 2005

Effects of Al and Cr alloying elements on the corrosion behavior of Fe-Al-Cr alloy system was investigated using potentiodynamic and cyclic potentiodynamic polarization tests(CPPT) in the $H_2SO_4$ and HCI solutions. The corrosion morphologies in Fe-Al-Cr alloy were analysed by utilizing scanning electron microscopy(SEM) and EDX. It was found that the corrosion potential of Fe-20Cr-20Al was highest whereas the critical anodic current density and passive current density were lower than that of the other alloys in 0.1 M $H_2SO_4$ solution. The second anodic peak at 1000 mV disappeared in the case of alloys containing high Al and low Cr contents. Pitting potential increased with increasing Cr content and repassivation potential decreased with decreasing Al content in 0.1 M HCI solution. Fe-Al-Cr alloy containing high Al and Cr contents showed remarkably improved pitting resistance against $Cl^-$ attack from pit morphologies.