• Journal of the Korean Ceramic Society
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• v.52 no.2
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• pp.140-145
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• 2015

In this study, we verified the relationship among the electrical conductivity, chemical durability, and structure of conductive vanadate glass in which $BO_3$ and $BO_4$ and $V^{4+}$ and $V^{5+}$ coexist simultaneously. We prepared samples of vanadium borophosphate glass with various compositions, given by $50V_2O_5-xB_2O_3-(50-x)P_2O_5$(x = 0 ~ 20 mol%) and $70V_2O_5-xB_2O_3-(70-x)P_2O_5$(x = 0 ~ 10 mol%), and analyzed the electrical conductivity, chemical durability, FT-IR spectroscopy, thermal properties, density, and molar volume. Substituting $B_2O_3$ for $P_2O_5$ was found to improve the electrical conductivity, chemical durability, and thermal properties. From these results, we can draw the following conclusions. First, the electrons shift from the electron rich $V^{4+}$ to the electron deficient $BO_3$ as the $B_2O_3$ content increases. Second, the improvement in chemical durability and thermal properties is attributed to an increase in cross-linked structures by changing from a $BO_3$ structure to a $BO_4$ structure.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.11 no.5
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• pp.203-206
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• 2001

The applicability of shaped growth of yttrium orthovanadate was approved by successful growth of rod-like single crystals with the rectangular shape. Nd-doped single crystals with content of $Nd^{3+}$ ions of 1,2,3,5 atomic % in the starting melt were grown by the EFG technique with the size up to $10^{*}10mm$ in section and up to 85 mm in length. For the testing of the multiple growth of the orthovanadates, two and three Nd-and Yb-doped $YVO_{4}$ single crystals were grown by the EFG technique simultaneously up to 110 mm in length.

• 한국유가공학회:학술대회논문집
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• 1997.05a
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• pp.23-34
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• 1997

Calcium-stimulated ATPase ($Ca^{2+}$-ATPase) which has optimal pH value at 7.0 was found in the membrane fraction of human milk, and its enzymatic properties were studied. The purified $Ca^{2+}$-ATPase required 0.45 mM Ca ion for maximal activity. Among the nucleosides, $Ca^{2+}$-ATPase showed a higher substrate specificity to ATP and UTP than to CTP and GTP. $Ca^{2+}$-ATPase had apparent Km value of 0.065, and V max of 7.63 mol ATP hydrolyzed/mg pro-tein per min, respectively. $Ca^{2+}$-ATPase was potently inhibited by lanthanide, vanadate, and p-chloromercuribenzoate, and inactivated by EDTA, and CDTA and EGTA, but were unaffected by N-ethylmaleimide, $NaN_3$, ouabain, or oligomycin, and was completely inactivated by heating at $60^{\circ}C$ for 10 min. This enzyme activity was concentrated in the membrane fraction of the cream and skim milk membrane, but not founded in bovine milk.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.784-787
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• 2008

Nanoscale $YVO_4:Eu^{3+}$ phosphor has been synthesized by a mild hydrothermal reaction at various experimental conditions. The particle and luminescent properties of nanophosphors were characterized with X-ray diffraction, electron microscopy and photoluminescence. It has been found that pH value play a key factor both controlling particle size and luminous efficiency.

• Proceedings of the Optical Society of Korea Conference
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• 2003.02a
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• pp.220-221
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• 2003

Intracavity second harmonic generation of diode pumped solid state lasers in the visible and ultraviolet regions provide efficient, compact and robust light sources for various applications, such as optical data storage, material processing, spectroscopy and bioanalysis. Advantages of neodymium vanadate (Nd：$YVO_4$) as a gain medium for intracavity-doubled lasers over Nd：YAG lie in the facts that the gain spectrum consists of a single line with short absorption depth, and that the stimulated emission cross sections are larger. (omitted)

• Journal of Plant Biology
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• v.37 no.3
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• pp.271-276
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• 1994

The possibility that 1-aminocyclopropane-1-carboxylic acid (ACC)-uptake may be dependent on the H+-gradient established across the plsma membrane was tested in protoplasts isolated from 2.5 day old mungbean hypocotyls. The ACC-induced ethylene production was inhibited when the H+-gradient was collapsed by the treatment with carbonycyamide-p-trifluro-methoxy-phenylhydrazone (FCCP). Moreover, the treatment with o-vanadate, a specific inhibitor of plasma membrane H+-ATPase, caused the inhibition of ethylene production. The ACC-induced ethylene production was inhibited by the treatemnt with verapamil (Ca2+-channel blocker), or ethylene glycol-bis($\beta$-aminoethyl ether) N, N, N', N'-tetraacetic acid (EGTA) (Ca2+-chelator). In contrast, the ehtylene production was stimulated by the application of A23187 (Ca2+ ionophore). The inhibitory effect of EGTA in the ethylene producton was magnified in the presence of A23187. From these results, we suggest that the external Ca2+ influx to the cytosol resulted in the stimulatin of ACC oxidase activity after ACC-uptake resulting from a H+-gradient across the plasma membrane.

• Proceedings of the Materials Research Society of Korea Conference
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• 2012.05a
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• pp.57.2-57.2
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• 2012

산소 이온 전도성 세라믹을 이용한 고체 산화물 연료전지의 전극은 원활한 전기화학반응을 위해, 이온 전도도, 전자 전도도 및 전기화학적 활성을 동시에 가지고 있어야 한다. 이를 위해 복합체 전극을 사용하며, 특히 음극의 경우 니켈(Nickel)과 Yttria-stabilized zirconia (YSZ)로 이루어진 복합체 전극을 혼합 및 소결을 통해 제조하여 사용하였다. 하지만, 니켈의 경우 탄화 수소 연료에서의 탄소 침적 문제와 열악한 산화환원 안정성(redox stability)등의 문제점을 가지고 있다. 따라서 니켈대신 전도성 세라믹을 사용한 세라믹 복합체 음극 개발이 활발히 이루어지고 있으며, 그 중 침투법(infiltration method)을 이용한 복합체 전극 제조 방법을 소개한다. 실제로 니켈 금속과 유사한 높은 전기 전도도를 갖는 Sr-doped Lanthanum Vanadate (LSV)을 이용해, YSZ-LSV 복합체 전극을 침투법을 이용해 제조하고, 소량의 촉매을 첨가하여, 이온전도도, 전자 전도도 및 촉매 활성을 갖는 복합체 음극을 제조하였다. 이 복합체 음극의 탄화수소에서의 연료전지 성능 및 redox stability을 측정하였다.

• Bulletin of the Korean Chemical Society
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• v.33 no.7
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• pp.2341-2344
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• 2012

A molecular orbital study is presented of the magnetic coupling in the one-dimensional vanadium oxide $Ba_2V_3O_9$ with a bridge formed by two different types of $VO_4$ tetrahedra. The concept of complementary versus counter-complementary effect has been used to explain the structural origin of the magnetic behavior of the compound. Namely, the observed antiferromagnetic coupling is dominated by the orbital complementarity of the V(1) tetrahedra sharing only one oxygen corner with two adjacent $VO_6$ octahedra. The second type of V(2) tetrahedra does not provide a noticeable contribution to the magnetic coupling due to the orbital counter-complementarity of the bridging ligand.

• Environmental Engineering Research
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• v.10 no.1
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• pp.31-37
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• 2005

The selective catalytic experiments using both sulfated/sulfur-free titania and V2O5/TiO2 catalysts have been conducted for NO reduction by NH3 in a packed-bed, down-flow reactor. The sulfated and vanadia loaded titania exhibited higher activity for NO removal than the sulfur-free catalysts, where > 90% NO removal was achieved over the sulfated V2O5/TiO2 catalyst between 280∼500 C. The surface structure of vanadia species on the catalyst surface played a critical role in the high performance of catalysts in which the existence of monomeric/polymeric vanadate is revealed by Raman spectra studies. Water vapor and SO2 were added to the reacting system for the catalyst deactivation tests. At higher temperatures (T ≥ 350 C), little deactivation was observed over the sulfated V2O5/TiO2 catalysts, showing good durability against SO2 and water vapor, which is compared with deactivation at lower temperatures.

• Applied Biological Chemistry
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• v.45 no.2
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• pp.53-58
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• 2002

Quinacrine, a pH-sensitive fluorescence probe, which exists either as an unprotonated fluorescence form or a protonated noufluorescence form, can be used to measure the proton transport activity of $H^+-ATPase$. Quinacrine was used to determine the optimal conditions for measuring the activity of microsomal $H^+-ATPase$ prepared from the roots of tomato plants. The amount of quinacrine fluorescence quenching obtained at $0.43{\mu}g/{\mu}l$ of microsomal protein concentration was 25-26%, which shows that the enzyme activity of 100 nmol/min decreases 10% of quinacrine fluorescence. Maximal fluorescence quenching was obtained at pH 7.0-7.2 and 2 mM $Mg^{2+}$ Because the activity of microsomal $H^+-ATPase$ is also maximal at these conditions, the quinacrine fluorescence well represents the activity of $H^+-ATPase$. Vanadate and $NO_3-$, specific inhibitors of plasma and vacuolar $H^+-ATPases$, respectively, were successfully applied to inhibit the quinacrine fluorescence quenching mediated by the corresponding $H^+-ATPases$. These results imply that quinacrine is a useful tool for measuring the proton transport activities of microsomes obtained from the root tissue of tomato plants.