• Proceedings of the Korean Magnestics Society Conference
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• 2012.05a
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• pp.112-113
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• 2012

• Transactions of the Korean hydrogen and new energy society
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• v.32 no.1
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• pp.41-52
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• 2021

NiO and Co3O4-doped porous La(CoNi)O3 perovskite oxides were prepared from excess Ni addition by a hydrothermal method using porous silica template, and characterized as bifunctional catalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) for Zn-air rechargeable batteries in alkaline solution. Excess Ni induced to form NiO and Co3O4 in La(CoNi)O3 particles. The NiO and Co3O4-doped porous La(CoNi)O3 showed high specific surface area, up to nine times of conventionally synthesized perovskite oxide, and abundant pore volume with similar structure. Extra added Ni was partially substituted for Co as B site of ABO3 perovskite structure and formed to NiO and Co3O4 which was highly dispersed in particles. Excess Ni in La(CoNi)O3 catalysts increased OER performance (259 mA/㎠ at 2.4 V) in alkaline solution, although the activities (211 mA/㎠ at 0.5 V) for ORR were not changed with the content of excess Ni. La(CoNi)O3 with excess Ni showed very stable cyclability and low capacity fading rate (0.38 & 0.07 ㎶/hour for ORR & OER) until 300 hours (~70 cycles) but more excess content of Ni in La(CoNi)O3 gave negative effect to cyclability.

• Journal of Ceramic Processing Research
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• v.19 no.5
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• pp.383-387
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• 2018

Highly transparent $Y_2O_3$ ceramics were produced using spark plasma sintering (SPS) at $1600^{\circ}C$ and 30 MPa for 5 min. When the SPS process was applied with various amounts of $La_2O_3$ as dopant. The specimen doped with 3 mol% $La_2O_3$ showed the highest density, and rapid particle growth and pore growth occurred, exhibiting that the relative density and average grain size are 99.2% and $17.2{\mu}m$, respectively. The specimen showed excellent transmittance of 79.44% in the visible light region (600 nm), resulting that $La_2O_3$ would be a useful dopant for improving the transmittance and mechanical properties of transparent $Y_2O_3$ ceramics produced with SPS.

• Bulletin of the Korean Chemical Society
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• v.28 no.2
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• pp.225-228
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• 2007

Lipoic acid (LA) is a multifunctional antioxidant against a variety of ROS. Nitrone acts as free radical spin trap and exhibits neuroprotective activity. Thus, LA-nitrone derivatives (6, 7, 8, and 9) were synthesized and screened as an antioxidant and inhibitors for cholinesterases. Even though the antioxidant effect of LA-nitrone derivatives was not improved, they turned out to be effective inhibitors of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) in μM range.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.11
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• pp.1487-1494
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• 2009

The major histocompatibility complex (MHC) plays well-defined roles in eliciting immune responses and combating infectious diseases. The major histocompatibility complex of cattle is referred to as BoLA (Bovine Lymphocyte Antigen). This genetic system is among the most polymorphic. In the present study, polymorphism of the BoLA- DRB3.2 locus in three Bos indicus breeds viz., Sahiwal, Rathi and Hariana was studied by polymerase chain reaction restriction fragment length polymorphism technique using the enzymes RsaI, Bst Y1 and Hae III. Both Sahiwal and Rathi are good Indian dairy breeds and survive under tough tropical conditions, while Hariana is a prominent dual-purpose breed reared both as a dairy animal and for bullock production. A total of 30 different BoLADRB3.2 alleles were observed to be present in the 3 Bos indicus breeds. Certain alleles were common amongst the three breeds while there were others that were unique to each breed. Allelic distribution amongst the three breeds showed that each breed had a unique allelic distribution pattern that was different from each other and also different from the earlier breeds studied so far for the existence of allelic variation at this locus. A dendogram was constructed based on the frequencies of the BoLA-DRB3 alleles using the UPGMA method. The Rathi and Hariana animals were genetically the most apart. The Hariana animals clustered on a different branch from the other two breeds viz. the Rathi and the Sahiwal. The smallest genetic distances for the DRB3 alleles were those between Sahiwal and Rathi (0.5461) while genetic distance between Hariana and Sahiwal was 0.6123. A comparison of the allelic frequencies of the BoLADRB3.2 locus in these 3 breeds viz. Sahiwal, Hariana and Rathi with the allelic frequencies present in the previously characterized Bos indicus Kankrej breed, which is a dual purpose breed reared both as a draught and a dairy animal, showed that the Bos indicus Sahiwal and Rathi breeds clustered into one group while the Hariana and Kankrej breeds formed another group. The Rathi and Sahiwal showed the least genetic distance of 0.5461 amongst the breeds whereas the Rathi and Kankrej, with a Nei''s genetic distance of 1.1622, were genetically the most distant apart.

• Nuclear Engineering and Technology
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• v.52 no.6
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• pp.1297-1303
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• 2020

In this study, nuclear radiation shielding and rigidity parameters of Y (0.1-x)B0.6Bi1.8O3La2x glassy system were investigated in order to determine it's suitability for use as nuclear radiation shielding materials. Therefore, a group of bismuth borate glass samples with La₂O₃ additive were synthesized using the technique of melt quenching. According to the results, the increase of the La₂O₃ additive increases the density of the glass samples and the mass attenuation coefficient (μ_m) values, whereas the half-value layer (HVL) and mean free path (MFP) values decrease. The effective atomic number (Z_eff) is also enhanced with an increment of both mass removal cross section for neutron (Σ_R) and absorption neutron scattering cross section (σ_abs). In addition to the other parameters, rigidity parameter values were theoretically examined. The increase of La₂O₃ causes some other important magnitudes to increase. These are the average crosslink density, the number of bonds per unit volume, as well as the stretching force constant values of these glass samples. These results are in concordance with the increase of elastic moduli in terms of the Makishima-Mackenzie model. This model showed an increase in the rigidity of the glass samples as a function of La₂O₃.

• Journal of Ceramic Processing Research
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• v.20 no.2
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• pp.158-163
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• 2019

Er3+/Yb3+-codoped NaLa(MoO4)2 colloidal nanocrystals were synthesized by pulsed laser ablations in de-ionized water and sodium dodecyl sulfate (NaC12H25SO4, SDS) aqueous solution for up-conversion (UC) luminescence bio-labeling applications. The influences of the SDS molecules on the crystallinities, crystal morphologies, crystallite sizes, and UC luminescence properties of the prepared Er3+/Yb3+-codoped NaLa(MoO4)2 colloidal nanocrystals were investigated in detail. Under a 980-nm excitation, the Er3+/Yb3+-codoped nanocolloidal NaLa(MoO4)2 suspension exhibited a weak red emission near 670 nm and strong green UC emissions at 530 and 550 nm, corresponding to the intra 4f transitions of Er3+ (4F9/2, 2H11/2, 4S3/2) → Er3+ (4I15/2). When the SDS solution was used, a smaller average crystallite size, narrower size distribution, and enhanced UC luminescence were observed. These characteristics were attributed to the amphoteric SDS molecules attached to the positively charged Er3+/Yb3+-codoped NaLa(MoO4)2 colloidal nanocrystals, effectively occupying the oxygen defect on their surfaces. The Er3+/Yb3+-codoped nanocrystalline NaLa(MoO4)2 suspension prepared in the SDS solution exhibited a remarkably strong green emission visible to the naked eyes.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.9 no.1
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• pp.74-79
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• 1999

Langasite($La_3Ga_5SiO_14$) is a new piezoelectric material which is similar to quartz, LN($LiNbO_3$) and LT($LiTaO_3$) in its acoustic behavior. In this study, pure Langasite and Lagnasite family groups were synthesized by the solid state reactions in air. The diffusion species for synthesis were investigated and the sintered body was studied on dielectric property to comparison of characteristics. Also, Langasite single crystals were grown by self-designed Czochralski system and characterized.

• 한국신재생에너지학회:학술대회논문집
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• 2006.11a
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• pp.368-371
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• 2006

[ $La_{0.8}Sr_{0.2}Co_{1-x}Mn_xO_3$ ] cathode as a high performance cathode on YSZ electrolyte was studied by analyzing impedance spectra. It was shown that cathode property of $La_{0.8}Sr_{0.2}Co_{1-x}Mn_xO_3$ is bet ter than that of$La_{0.8}Sr_{0.2}CoO_3$. At $700^{\circ}C$ in air environment, $La_{0.8}Sr_{0.2}Co_{0.4}Mn_{0.6}O_3$ cathode on CGO- layered YSZ electrolyte showed very low area specific resistance of $0.14{\Omega}cm^2$, which is low enough for intermediate-temperature sol id oxide fuel cells. This is because material properties of ionic conductivity and thermal expansion compatibility with electrolyte were optimized. Judging from activation energy and oxygen part i al pressure dependance of cathode property, it was noted that oxygen surface exchange kinetics is dominantly influential on cathode property in higher temperature region than $700^{\circ}C$ and oxygen self-diffusion in cathode material is more influential in lower temperature region.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.1017-1020
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• 2003

The effect of doping Gd, La for Y into $YVO_{4}:Eu^{3+}$ red phosphor on its photoluminescence(PL) intensity has been investigated. $YVO_{4}:$Eu-based phosphors were prepared by solid-state reaction at temperature above $1200^{\circ}C$. Under UV excitation(254, 365 nm), it was measured that $YVO_{4}:Eu^{3+}$ was superior to a commercial red phosphor (Y,Gd)$BO_{3}:Eu^{3+}$ in terms of PL intensity and CIE color coordinates. When La, Gd were doped into $YVO_{4}:Eu^{3+}$, the change in the structure of the host material was observed. In result, when the ($Y{1_x}La_{x})VO_{4}:Eu^{3+}$ phosphors were excited by 365 nm excitation, its PL intensity was improved up to about 30 % for the case of x being $0.4{\sim}0.6$.