• Journal of the Korean Wood Science and Technology
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• v.35 no.2
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• pp.85-95
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• 2007

Manganese dependent peroxidase (MnP) is the most ubiquitous enzyme produced by white-rot fungi, MnP is known to be involved in lignin degradation, biobleaching and oxidation of hazardous organopollutants. Bjerkandera fumosa is a nitrogen-unregulated white-rot fungus, which produces high amounts of MnP in the excess of N-nutrients due to increased biomass yield. The objective of this study was to optimize the MnP production in N-sufficient cultures by varying different physiological factors such as Mn concentration, culture pH, and incubation temperature. The growth of fungus was optimal in pH 4.5 at $30^{\circ}C$, $N_2$-unregulated white-rot fungus produces high amounts of MnP in the excess N-nutrients. The fungus produced the highest level of MnP (up to $1000U/{\ell}$) with $0.25g/{\ell}$ asparagine and $1g/{\ell}$ $NH_4Cl$ as N source at 1.5 mM $MnCl_2$ concentration, pH value of 4.5 at $30^{\circ}C$. Purification of MnP revealed the existence of two isoforms: MnPl and MnP2. The molecular masses of the purified MnPl and MnP2 were in the same range of 42~45 kDa. These isoforms of B. fumosa strictly require Mn to oxidize phenolic substrates. Concerned to kinetic constants of B. fumosa MnPs, B. fumosa has similar Km value and Vmax compared to the other white-rot fungi.

• Journal of the Korean Magnetics Society
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• v.19 no.4
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• pp.126-132
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• 2009

We have studied physical properties of MnAs thin films grown by Molecular-Beam Epitaxy as well as their post-growth annealing effects. The samples grown at $600^{\circ}C$ show the preferred crystal orientation of type-B independent of substrate whereas type-A is observed for the samples grown at below $200^{\circ}C$. The sample grown at $600^{\circ}C$ on GaAs(001) substrate is magnetized to only one direction even on the easy axis of magnetization. The magnetic properties are vastly enhanced after post-growth annealing for both MnAs/Si(001) sample with no ferromagnetism and ferromagnetic MnAs/GaAs(001) grown at $200^{\circ}C$.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.9 no.1
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• pp.126-131
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• 1999

$Cd_{1-x}Mn_xTe$ thin films were grown on GaTs (100) substrates by hot-wall epitaxy method. From the XRD measurements, it was found that CdTe/GaAs (100)film was grown as a single crystal with the same growth plane of (100) and $Cd_{1-x}Mn_xTe$film as a poly crystal as Mn content was increased, and the lattice constant was decressed with the similar gradient of bulk crystal as x was increased. From the PL measurements, $L_1$line due to the exciton trapped on an acceptor and $L_2$line due to an exciton trapped on a shallow potential fluctuation were observed, and $L_1$line was observed only in $Cd_{0.91}Mn_{0.09}$te but it was disappeared probably due to a stronger lacalization of excitons with increasing alloy fluctuation.$L_2$line was dominant in case of $x{\ge}0.2$and for higher Mn contents the broad transition about 2.0eV associated to the 3d levels of the $Mn^{2+}$ ion dominated the PL spectrum, and the $L_2$ transition become weaker and weaker. For$x{\ge}0.4$, the transition line about 2.0eV due to $Mn^{2+}$ion showed no shift.

• Transactions on Electrical and Electronic Materials
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• v.18 no.1
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• pp.46-50
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• 2017

The Zn1-xMnxO ($0.00{\leq}x{\leq}0.06$) samples have been synthesized in the form of powder by the coprecipitation method at low temperature using $Zn(CH_3COO)_2$. $2H_2O$ and $Mn(CH_3COO)_2$. $4H_2O$ powders, as well as HCl and $NH_4OH$ solutions as starting materials. Characterization was conducted using XRD, TEM, XRF, FTIR and VSM. The result shows that the $Zn_{(1-x)}Mn_xO$ ($0.00{\leq}x{\leq}0.06$) nanoparticles have the wurtzite phase with a hexagonal structure and particle sizes ranging from 17.48 to 118.83 nm. In a qualitative analysis of XRF, the peaks that confirm the existence of the manganese element in Mn-doped ZnO samples were observed. Meanwhile, FTIR test result shows that there are peaks at around $500cm^{-1}$ and $400cm^{-1}$ in the FTIR spectra for Mn doped ZnO samples which clearly reveal the existence of the (Zn, Mn)-O strain mode. The (Zn, Mn)-O absorption peak positions have shifted to a lower wave number with increasing Mn doping content. The peak intensity is also lower if compared to that of the ZnO sample without doping. From the VSM test, it is shown that $Zn_{(1-x)}Mn_xO$ ($0.00{\leq}x{\leq}0.06$) nanoparticles are all paramagnetic having monotonically increased susceptibility as increasing Mn content.

• Journal of Korea Foundry Society
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• v.29 no.6
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• pp.270-276
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• 2009

After casting button-type small ingots of ternary Fe-Mn-S alloys which had three different Mn/S ratios (1, 5 and 70) in a vacuum arc furnace, the effect of the ratio on the sulfide formation was investigated. In case of the Mn/S ratio of 1, if alloy composition was located in an iron-rich corner on a Fe-Mn-S ternary phase diagram, only duplex MnS-FeS sulfide films were observed in the grain boundary. If the alloy composition was located in the miscibility gap area of the phase diagram, primary globular dendritic sulfides and dendritic sulfide slags were generated within the grain and tubular monotectic sulfides were also detected in the grain boundary. When the Mn/S ratio was 5, if the alloy composition was in the iron-rich corner, only bead-like sulfides were generated. On the other hand, if the composition was in the miscibility gap area, globular dendritic sulfides and dendritic sulfide slags were generated in the form of primary sulfide inclusions and rod-like eutectic sulfides were observed in the grain boundary. Especially, if the contents of Mn and S increased more in the miscibility gap area of the phase diagram, primary globular sulfides containing iron intrusions were observed. In case of Mn/S ratio of 70, if the contents of Mn and S was decreased in the Fe corner of the phase diagram, only bead-like sulfides were observed in the grain boundary. Despite the composition was outside the miscibility gap area of the phase diagram, if the contents of Mn and S increased, clusters of fine sulfide particles as well as fine spherical primary monophase sulfides were observed in the grain boundary.

• Journal of the Korean Magnetics Society
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• v.13 no.5
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• pp.187-192
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• 2003

The magnetic and thermal properties of NiFe/[IrMn-Mn]/CoFe with Mn additions have been studied. As-deposited CoFe pinned layers with [IrMn-Mn]layer had dominantly larger exchange biasing field ( $H_{ex}$) and blocking temperature ( $T_{b}$) than those with pure I $r_{22}$M $n_{78}$ used. The $H_{ex}$ and $T_{b}$ improved with 76.8-78.1 vol% Mn, but those of the NiFe/IrMn/CoFe dropped considerably with more addition of 0.6 vol % Mn. The average x-ray diffraction peak ratios of fcc [(111)CoFe, NiFe]/(111)IrM $n_3$ textures for the Mn inserted total vol of 75.5, 77.5, and 79.3% were about 1.4, 0.8, and 0.6, respectively. For the sample without Mn inserted layer, the $H_{ex}$ between IrMn and CoFe layers was almost zero, but it increased to 100 Oe after annealing of 250 $^{\circ}C$. For as-grown two multilayers samples with ultra-thin Mn layers of 77.5 and 78.7 vol %, the $H_{ex}$s were 259 and 150 Oe, respectively. In case of IrMn with 77.5 vol% Mn, the $H_{ex}$ was increased up to 475 Oe at 350 $^{\circ}C$ but decreased to 200 Oe at 450 $^{\circ}C$, respectively. The magnetic properties and thermal stabilities of NiFe/[IrMn-Mn]/CoFe multilayer were enhanced with Mn additions. In applications where higher $H_{ex}$ and $T_{b}$ are required, proper contents of Mn can be used. be used. used.

• Journal of the Korean Ceramic Society
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• v.37 no.5
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• pp.466-472
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• 2000

As cathode materials of LiMn2O4-based lithium-ion secondary batteries, Li(Mn1-$\delta$M$\delta$)2O4 (M=Ni and Co, $\delta$=0, 0.05, 0.1 and 0.2) materials which Co and Ni are substituted for Mn, were syntehsized by the solid state reaction at 80$0^{\circ}C$ for 48 hours. No second phases were formed in Li(Mn1-$\delta$M$\delta$)2O4 system with substitution of Co. However, substitution of Ni caued to form a second phase of NiO when its composition exceeded over 0.2 of $\delta$ in Li(Mn1-$\delta$M$\delta$)2O4. As the results of charging-discharging test, the maximum capacity of Li(Mn1-$\delta$M$\delta$)2O4 appeared in $\delta$=0.1 for both Co and Ni. Also, Li(Mn1-$\delta$M$\delta$)2O4 electrode showed higher capacity and better cycle performance than LiMn2O4.

• Journal of Korean Society on Water Environment
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• v.20 no.2
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• pp.176-182
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• 2004

The purpose of this study was to investigate the heterogeneous catalytic ozonation of oxalic acid by manganese (Mn) doped-granular activated carbon (GAC). In order to observe the effect of the amount of Mn doped on GAC, catalysts were manufactured by varying the impregnated Mn concentration. In this paper, the following had labeled all sorts kinds of Mn-doped GAC were labeled with suitable names according to the amount (mM) of the concentration of dipping solution: They were each named as 'Mn20', 'Mn50', 'Mn100' and 'Mn200'. These experiments were performed in a batch reactor (0.5 L) and a semi-batch reactor (1 L) and Mn-free GAC was used as a blank catalyst. The ozone decay properties of each manufactured catalyst were firstly investigated to find out the reactivity between the aqueous ozone and the catalysts. Oxalic acid removal by catalytic ozonation was then performed to demonstrate the oxidative efficiencies of each catalyst.

• Journal of the Korean Ceramic Society
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• v.25 no.6
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• pp.571-576
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• 1988

The microstructure and electrical properties of 0.02Pb[Cd1/2W1/2)O3-0.505PbZrO3-0.475PbTiO3 with MnO2 addition have been investigated. The amount of MnO2 addition was 0, 0.2, 0.4, 0.6, 0.8, 1wt%, respectively. When MnO2 is added up to 0.2wt%, Mn3+ which is substituted for Ti4+ site make hole and act as a acceptor. When MnO2 is added over 0.2wt% Mn3+ which is substituted for Cd2+ site create electron and act as a donor. The variation of grain size show that it was rapidly increased by 0.4wt% addition of MnO2, and while that in the range of over 0.6wt% addition of MnO2 it was decreased. The solid solution range of MnO2 that assumed in this composition according to the variations of microstructure and electrical properties was 0.4-0.6wt%.

• Journal of the Korea Convergence Society
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• v.9 no.10
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• pp.271-276
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• 2018

In the industry, Zn galvanizing on the steel using the principle of sacrificial anode is used. The steel have some problem, specially corrosion problem. To solve corrosion problem, Zn-Mn alloy plating has been studied as one of the measures to increase the corrosion resistance rather than pure zinc plating. It is possible to be applied to automotive parts requiring high corrosion resistance even though the plating cost is high. In this study, Zn-Mn alloys were electrodeposited from an acidic chloride bath. The influence of the electrolytic conditions on the composition of the alloy plating in the chloride bath was investigated. As the current density of the cathode increases, Zn content of electrodeposit decrease and Mn content of electrodeposit increase. As the temperature of the electrolyte increases, Zn content of electrodeposit decrease and Mn content of electrodeposit increase. The results are explained by the cathode overvoltage curve of Mn and Zn.