• The Transactions of the Korean Institute of Electrical Engineers
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• v.44 no.4
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• pp.479-482
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• 1995

In this study, to improve sintering condition, anisotropic properties ( $k_{t}$/ $k_{p}$) of electromechanical coupling coefficient and piezoelectric constant $d_{h}$ and $g_{h}$, Mn $O_{2}$ impurity was added to the (P $b_{0.76}$C $a_{0.24}$)[( $Co_{1}$2/ $W_{1}$2/)$_{0.04}$ $Ti_{0.96}$] $O_{3}$ ceramics for application to hydrophone devices. Electromechanical coupling coefficients of the specimen with 1.5 [mol%] Mn $O_{2}$ sintered at 1150.deg. C were $k_{t}$=49% and $k_{p}$ = O, which exibited the highest value in piezoelectric anisotropic properties (kt/kp). Without relations with sintering temperature, the highest value of hydrostatic piezoelectric constant $d_{h}$ & $g_{h}$ were shown at the specimen with 1.5 [mol%] Mn $O_{2}$. Accordingly, the best addition amount of Mn $O_{2}$ was 1.5 [mol%] and proper sintering temperature was 1150.deg. C. Hydrostatic piezoelectric constant values of $d_{h}$=64.52[10$^{-12}$ C/N], $g_{h}$=35.92[10$^{-3}$ Vm/N] in the above condition were effectiely extended for hydrophone applications.pplications.ons.

• Journal of Powder Materials
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• v.24 no.5
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• pp.400-405
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• 2017

The addition of a large amount of alloying elements reduces the compactibility and increases the compacting pressure, thereby shortening the life of the compacting die and increasing the process cost of commercial PM steel. In this study, the characteristic changes of Fe-Mo-P, Fe-Mn-P, and Fe-Mo-Mn-P alloys are investigated according to the Si contents to replace the expensive elements, such as Ni. All compacts with different Si contents are fabricated with the same green densities of 7.0 and $7.2g/cm^3$. The transverse rupture strength (TRS) and sintered density are measured using the specimens obtained through the sintering process. The sintered density tends to decrease, whereas the TRS increases as the Si content increases. The TRS of the sintered specimen compacted with $7.2g/cm^3$ is twice as high as that compacted with $7.0g/cm^3$.

• Journal of the Korean Wood Science and Technology
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• v.21 no.3
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• pp.87-93
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• 1993

This study was undertaken to investigate the characteristics and the productivities of lignin olytic enzymes: laccase (Lac) and Mn-dependent peroxidase (MnP) from Coriolus versicolor and Lentinus edodes respectively. Enzymes were isolated from cultural filterates and purified according to the standard methods. These enzymes showed one band in SDS-PAGE and their molecular weights were found 62,000 and 45,000 dalton respectively. Polyclonal antibodies against Lac and MnP were raised against mouse. In the ELISA (enzyme-linked immunosorbent assay), Lac and MnP-antiserum produced a strong positive reaction with Lac and MnP antigen($A_{405}$=2.50 and 3.53 respectively). The sera to negative (S/N) ratio was determined by the dividing the mean absorbance of antibodies by the corresponding diluted samples from normal mouse serum. The sera produced showed 2 times more positive reaction in S/N ratio than negative sera.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1994.11a
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• pp.3-7
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• 1994

In this study, to improve sintering condition, anisotropic Property(k$\_$t//k$\_$p/) of electromechanical coupling coefficients, and hydrostatic piezoelerlric constants d$\_$h/ and g$\_$h/, MnO$_2$impurity was added to the (Pb$\_$0.76/Ca$\_$0.24)[(Co$\_$$\frac{1}{2}$W$\_$$\frac{1}{2}$/)$\_$0.04/Ti$\_$0.96/]O$_3$ System ceramics for hydrophone. And the structural, electrical properties of them were investigated. As a results. tetragonality was decreased with MnO$_2$ additives and density was the highest value of 7.06(g/㎤) at H2-3 specimen. Electromechanical coupling coefficients of H2-3 specimen were k$\_$t/=49 and k$\_$p/ 0, which exibited the hightest hydrostatic piezoelectric constants of d$\_$h/=64.52[10$\^$-1/C/N] and g$\_$h/=35.92[10$\^$-3/ Vm/N].

• Journal of Microbiology
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• v.45 no.3
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• pp.213-218
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• 2007

Trametes versicolor has a lignin degrading enzyme system, which is also involved in the degradation of diverse recalcitrant compounds. Manganese-dependent peroxidase (MnP) is one of the lignin degrading enzymes in T. versicolor. In this study, a cDNA clone of a putative MnP-coding gene was cloned and transferred into an expression vector (pBARGPE1) carrying a phosphinothricin resistance gene (bar) as a selectable marker to yield the expression vector, pBARTvMnP2. Transformants were generated through genetic transformation using pBARTvMnP2. The genomic integration of the MnP clone was confirmed by PCR with bar-specific primers. One transformant showed higher enzyme activity than the recipient strain did, and was genetically stable even after 10 consecutive transfers on non-selective medium.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.161-164
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• 2001

In this paper, we investigated the dielectric and piezoelectric properties of Pb(Sb, Nb)O$_3$-Pb(Zr, Ti)O$_3$ ceramic(PSN) for piezoelectric transformer and actuator etc. Effect of MnO$_2$ addition on the PSN ceramic was investigated. Anisotropic properties of electromechanical coupling factor and piezoelectric properties proved to be varied with amount of MnO$_2$ impurity and sintering temperature. The electromechanical coupling factor k$_{p}$ of 0.38 and the mechanical quality factor Q$_{m}$ of 1944 were obtained from the specimen with 0.4 wt% MnO$_2$ sintered at 115$0^{\circ}C$ addition. Experimental results indicated that the PSN ceramic with MnO$_2$ impurity can be effectively used for piezoelectric transformer and actuator.tor.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07b
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• pp.790-793
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• 2004

이중의 망간 perovskite 블록을 가진 Ruddlesden-Popper 상(R-P phase) $Sr_3Mn_2O_7$ 은 공기중에서 불안정하다. 본 연구에서는 망간 이온 자리에 철 이온을 소량 치환 함으로써 R-P 상을 안정화 시켰으며 이들의 결정구조는 X-선회절 데이터를 이용하여 Rietveld 법으로 정밀화하였다. 안정화에 필요한 Fe 이온의 양은 약 x=0.15로 나타났으며 Fe이온의 양이 증가함에 따라 쉽게 안정화 되었다. 자화율 측정결과 x=0.20 시료는 120K에서 paramgnetic-antiferromagnetic 전이를 나타내었고 이 전이 온도는 치환되는 Fe이온의 양이 증가함에 따라 감소하는 경향을 나타내었다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.351-352
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• 2009

이중의 망간 페로브스카이트 블록을 가진 Ruddlesden-Popper 상 (R-P phase) $Sr_3Mn_2O_7$은 공기중에서 불안정하다. 본 연구에서는 Sr이온 자리에 La, Ca이온을 치환함으로써 R-P상을 안정화 시켰으며, 이들의 결정구조는 Neutron Diffraction 데이터를 이용하여 Rietveld 법으로 정밀화하였다 $La_{1.4}Sr_{0.8}Ca_{0.8}Mn_2O_7$, $La_{1.2}Sr_{0.9}Ca_{0.9}Mn_2O_7$은 $T_N$이 80K이며 25K에서 spin-glass 변이가 관찰되었다.

• Korean Journal of Microbiology
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• v.46 no.1
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• pp.93-95
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• 2010

White rot fungi which have lignin degrading enzymes show high degrading activity to diverse recalcitrant compounds such as polycyclic aromatic compounds, dyes, explosives and endocrine disrupting chemicals. We have examined decolorizing activity of dyes by Phlebia tremellosa and two transformants which had genetically transformed using laccase or manganese peroxidase (MnP) gene. In case of methyl green, wild type strain showed 50% decolorization while laccase transformant (TF2-1) and MnP transformant (T5) showed more than 90% decolorization on day 3. Remazol brilliant blue R(RBBR) was decolorized up to 85% by two transformants while the wild type showed 67% decolorization on day 3. Transformants TF2-1 and T5 both showed increased laccase and MnP activity respectively during the whole growing phase.

• The Korean Journal of Ceramics
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• v.4 no.2
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• pp.68-71
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• 1998

The effect of Mn and Nb additions on the electrical properties of BaTiO$_3$ has been studied by means of equilibrium electrical conductivity as a function of temperature, oxygen partial pressure(Po$_2$) and composition. If the manganese ion is added to the normal Ti site, i.e. BaTi$_{1-x}Mn_xO_{\delta-6}$, the equilibrium conductivity shows strong evidence of acceptor-doped behavior. The conductivity minimum, corresponding to the transition from oxygen excess, p-type behavior to oxygen deficient, n-type behavior with decreasing Po$_2$, is displaced to lower Po$_2$ and is broadened and flattened. The partial replacement of Mn ion with Nb decreases the acceptor-doped effect and the total replacement exhibits a typical donor-doped behavior. It was confirmed that unlike undoped or other acceptor-doped behavior. It was confirmed that unlike undoped or other acceptor-doped samples, for the p-type region, the electrical conductivity follows the 1/6th power dependence of oxygen partial pressure.