• Journal of the Korean Magnetics Society
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• v.5 no.5
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• pp.720-725
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• 1995

Bi-substituted gadolinium iron garnet films were deposited on GGG(111) and NGG (111) substrates by irradiating KrF excimer laser onto targets having compositions of $Bi_{x}Gd_{3-x}Fe_{5}O_{12}$ ($2.0{\leq}x{\leq}3.0$) under substrate temperature of $580~620^{\circ}C$. Analysis on structure, composition and angle of Faraday rotation, ${\theta}_{F}$, were carried out. The composition, the structure and the magneto-optical properties of the obtained films were found to be strongly dependent both on the compositions of the targets and on the pressure of oxygen. Before annealing in air, all films showed ${\theta}_{F}{\geq}0$ at ${\lambda}=6328{\AA}$, while several films showed ${\theta}_{F}{\leq}0$ after the annealing. The highest value of Bi-substitution up to x = 1.76 with uniform composition was obtained.

• Journal of the Korean Ceramic Society
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• v.18 no.1
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• pp.13-22
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• 1981

This study is to investigate the effective mineralizer in the manufacture of forsterite porcelain as a high frequency insulator. A mixture of $Mg(OH)_2$. and $SiO_2$.($\alpha$-Quartz) corresponding to the molar ratio of 2.0 MgO: 1.0 $SiO_2$ was prepared from the materials of high purity. It was heated to 140$0^{\circ}C$ at the rate of 20$0^{\circ}C$/hr, which was kept constantly for 1 hour, and one has made chamotte after cooling. Six kinds of glasses were prepared by an 0.1 atomic equivalent of K ions substitution-Ba, Bi, Zn, Cd, Zr-to the basic K-glass (0.333 $K_2O$.1.14 $SiO_2$) and were melted approximately at 150$0^{\circ}C$. The forsterite bodies were provided by adding each glass (10, 15, 20, 25, 30%) to the forsterite chamotte, which was fired at 1320, 1360, 1400, 144$0^{\circ}C$. (1 hr). One has examined the physical and dielectric properties for the specimens. The results of the experiments are as follows; 1. As for water absorption: Bodies were better vitrified with an addition and temperature change of Ba, Bi, Zn-glasses. The specimen containing Cd-glass showed deviation of slow decreasing, where as K-glass was completely not vitrified. 2. Bodies containing Ba, Zn, Bi-glasses appeared comparatively high Modulus of Rupture at 136$0^{\circ}C$, while containing Zr-glass had the highest Modulus of Rupture as the addition changes remarkably at 140$0^{\circ}C$. 3. It was estimated that 20-25% glass present in a forsterite bodies were in good conditions as for physical properties. 4. Specimens of Ba, Bi, Zr-glasses were superior as for dielectric properties, where among Ba-glass was most excellent. 5. Dielectric constant commonly increases in a slight gradient as firing temperature rises. 6. The petrographic examination showed that the bodies containing Ba, Bi-glasses had fine crystals, and were observed distinctly large mosaic crystals in the Zn-glass.

• Korean Journal of Materials Research
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• v.13 no.5
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• pp.317-322
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• 2003

Bismuth layered structure ferroelectric thin films, $Bi_4$$Ti_3$$O_{12}$ / (BTO) and Nb-doped BTO (BTN) were prepared on the Pt(111)/Ti/$SiO_2$/Si(100) substrates by a sol-gel route. We investigated the Nb-doping effect on the grain orientation and ferroelectric properties. $Nb^{5＋}$ ion substitution for $Ti^{4＋}$ ion in perovskite layers of BTO decreased the degree of c-axis orientation and increased the remanent polarization (2Pr). The fatigue resistance of Nb-doped BTO thin film was shown to be superior to that of BTO, and the leakage current of Nb-doped BTO thin film was decreased about 1 order of magnitude compared with BTO. The improvement of ferroelectric properties with $Nb^{5＋}$ doping in BTO could be attributed to the changes in space charge densities and grain orientation in the thin film.

• Korean Journal of Materials Research
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• v.11 no.11
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• pp.960-964
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• 2001

$Bi_{3.99}Ti_{2.97}V_{0.03}O_{12}$ (BTV) thin films with 3 mol% vanadium doping were Prepared on $Pt/Ti/SiO_2/Si$ substrate by sol-gel method. X-ray diffraction analysis indicated that single-phase layered perovskite were obtained and preferred orientation was not observed. Under the annealing temperature at $600^{\circ}C$, the surface morphology of the BTV thin films had fine-rounded particles and then changed plate-like at $650^{\circ}C$ and $700^{\circ}C$. The remanent polarization $(2P_r)$ and coercive field $(2E_c)$ of $700^{\circ}C$ annealed BTV thin film were 25 $\mu$C/cm$^2$ and 116 kV/cm, respectively. In addition, BTV thin film showed little polarization fatigue during $10_9$ switching cycles. These improved ferroelectric properties were attributed to the increased rattling space and reduced oxygen vacancies by substitution $Ti^{4+}$ ion (68 pm) with smaller $V^{5+}$ ion (59 pm). The dielectric constant and loss were measured 130 and 0.03 at 10 kHz, respectively.

• Bulletin of the Korean Chemical Society
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• v.18 no.9
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• pp.972-976
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• 1997

Single phase ruthenium oxides with perovskite (ATi1-xRuxO3 (A=Ca, Sr)) and pyrochlore structure (Bi2Ru2O7, Pb2Ru2O6.5) have been prepared reproducibly by solid state reaction methods and their electrocatalytic activities for oxygen evolution have been examined by Tafel plots. Tafel slopes vary from a low value of 42 mV/decade up to 222 mV/decade at room temperature. The high exchange current densities and high Tafel slopes compared with those obtained from the RuO2 DSA electrode at the crystalline single phase metal oxide electrodes suggest that they are better electrocatalysts at low overpotentials. A favorable change in the Tafel slope for the oxygen evolution reaction occurs as the ruthenium content increases. Substitution of Ti for Ru in the perovskite solid solutions enhanced their chemical stability by losing marginal electrochemical activity.

• Korean Journal of Materials Research
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• v.8 no.10
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• pp.925-930
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• 1998

EPMA and XPS on $Bi_2Sr_2-\chi_LCa_1+\chi_LCu_2O_{8+d}$($\chi_L$ = 0.01, 0.2, 0.3, 0.4, 0.5, 0.6) films by LPE method were performed in order to investigate Sr and Ca distributions in SrO- and Ca-layers. It is found that $T_C^{zero}$ carrier concentration and lattice parameter c monotonically decreases with increasing $\chi_L$. Sr and Ca contents in Ca-layer change in proportion to that in melt. On the other hand, in SrO-layer, Ca content strongly depends on Sr content in that layer and not on Ca content in melt. Since deficiency in SrO-layer increases and $T_C^{zero}$ creases with $\chi_L$,t is found that the deficiencies of Sr and Ca atoms in the SrO-layer has a influence on reducing $T_C^{zero}$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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• pp.569-572
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• 2003

전력선 통신용 LC 공진필터에 사용되는 Ni-Zn 페라이트를 제조하기 위해 Ni0.8Zn0.2Fe2O4를 기본조성으로 선택하고 x (Co mol 비)를 변화시켜 전자기적 특성을 조사하였다. $Bi_2O_3$ CaO가 첨가됨으로써 균일한 입자성장과 입계에 고저항층이 형성되어 주파수 손실이 감소하였으며, $Ni_{0.8-x}Zn_{0.2}Co_xFe_2O_{\delta}$의 기본조성에 Co의 함량을 증가시키면 x = 0.05에서 투자율 75, 공진주파수 20 MHz의 특성을 나타내고 결정 입자 크기와 같은 구조적 특성에는 영향을 거의 미치지 않지만 자기이방성 변화에 따라 전자기적 특성에는 영향을 미친다. 또한, $Ni_{0.75}Zn_{0.2}Co_{0.05}Fe_2O_{4.017}$ 조성의 페라이트 코어의 발열량은 큐리온도 이하에서 일어난다.

• Journal of the Korean Ceramic Society
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• v.43 no.7 s.290
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• pp.421-426
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• 2006

[ $(BaSr)TiO_3$ ] thick films were prepared by tape casting method, using $BaTiO_3\;and\;SrTiO_3$ powder slurry in order to investigate dielectric properties i.e. dielectric constant, ${\varepsilon}_r$, Curie temperature, $T_c$. Grain growth within $(BaSr)TiO_3$ thick films was observed with increasing weight ratio of $BaTiO_3$. This observation can be explained by phenomena of substitution of $Sr^{2+}$ ion for $Bi^{2+}$ ion in the $BaTiO_3$ system. Also, the Curie temperature in $(BaSr)TiO_3$ thick films was shifted to lower temperature range with increasing $ SrTiO_3$. Furthermore, Curie temperature having maximum dielectric constant was in the range of $-40^{\circ}C\;to\;30^{\circ}C$, and hence sharper phase transformation occurred at Curie temperature. There occurred decrease in tunability and k-factor of $(Ba_{0.6}Sr_{0.4})TiO_3$ calculated from the dielectric constant, ${\varepsilon}_r$ above Curie temperature. In addition, above the $60^{\circ}C$, phase fixation was observed. This means that internal stress relief occurred with increasing $90^{\circ}$ domains.

• The Korean Journal of Ceramics
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• v.1 no.2
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• pp.91-95
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• 1995

Polycrystalline bismuth- and aluminum- substituted dysporsium and yttrium iron garnet (Bi2R3-xAlyFe5-yO12, R=Dy or Y, $0\leqx\leq3, \; 0\leqy\leq3$) films have been prepared by pyrolysis. The crystallization temperatures, the solubility limit of bismuth ions into the garnet phase, and magnetic and magneto-optic properties of the films have been investigated as a function of bismuth and aluminum concentration. It was found that the crystallization temperatures as a function of bismuth and aluminum concentration. It was found that the crystallization temperatures of these films rapidly decreased as bismuth concentration. It was found that the crystallization temperatures of these films rapidly decreased as bismuth concentration (x) increased up to x=1.5 and then remained temperatures of these films rapidly decreased as bismuth concentration (x) increased up to x=1.5 and then remained unchanged at x>1.5, whereas, showed no changes as aluminum concentration (y) increased up to y=1.0 and then gradually increased at y>1.0. The solubility limit of bismuth ions was x=1.8 when y=0 but increased to x=2.3 when y=1.0. It was demonstrated that the magnetic and magneto-optic properties of the dysprosium iron garnet films could be tailored by bismuth and aluminum substitution suitable for magneto-optic recording as follows. The saturation magnetization and coercivity data obtained for the films indicated that the film composition at which the magnetic compensation temperature became room temperature was y=1.2 when x=1.0. Near this composition the coercivity and the squareness of the magnetic hysteresis loop of the films were several kOe and unit, respectively. The Curie temperatures of the films increased with the increase of x but decreaed with the increase of y, and was 150-$250^{\circ}C$ when x=1.0 and y=0.6-1.4. The Faraday rotation at 633 nm of the films increased as x increased but decreased as y increased, and was 1 deg/$\mu\textrm{m}$ when x=1.0 and y=1.0. Based on the data obtained, the appropriate film composition for magneto-optic recording was estimated as near x=1.0 and y=1.0 or $BiDy_2AlFe_4O_{12}$.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.149-149
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• 2017

The RING (Really Interesting New Gene) finger proteins are known to play crucial roles in various abiotic stresses in plants. In this study, we report on RING finger E3 ligase, ${\underline{O}ryza}$ ${\underline{s}ativa}$ ${\underline{s}alt$-, ${\underline{A}BA}$- and ${\underline{d}rounght}$ stress-${\underline{i}nduced}$ RING finger ${\underline{p}}rotein{\underline{1}}$ gene (OsSAD1). In vitro ubiquitination assay demonstrated that unlike OsSAD1, a single amino acid substitution ($OsSAD1^{C168A}$) of the RING domain showed no E3 ligase activity, supporting the notion that the activity of most E3s is specified by a RING domain. Result of Yeast-Two hybridization, In vivo protein degradation assay supports that OsSAD1 interacting with 3 substrate, OsSNAC2, OsGRAS44 and OsPIRIN1, and mediates proteolysis of 3 substrates via the 26S proteasome pathway. Subcellular localizations of OsSAD1 while approximately 62% of transient signals were detected in cytosol, 38% of signals were showed nucleus. However, transiently expression of OsSAD1 was detected in cytosol 30% while as 70% of nucleus under 200 mM salt treated rice protoplasts. Results of bimolecular fluorescence complementation (BiFC) showed that two nucleus-localized proteins (OsSNAC2 and OsGRAS44) interacted with OsSAD1 in the both cytosol and nucleus. Heterogeneous overexpression of OsSAD1 Heterogeneous overexpresssion of OsSAD1 in Arabidopsis exhibited sensitive phenotypes with respect to Salt-, mannitol-responsive seed germination, seedling growth. In ABA conditions, OsSAD1 overexpression plants showed highly tolerance phenotypes, such as root length and stomatal closure. Our findings suggest that the OsSAD1 may play a negative regulator in salt stress response by modulating levels of its target proteins.