• Proceedings of the Korean Vacuum Society Conference
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• 1994.02a
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• pp.50-50
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• 1994

Half-metallic Heusler alloys (NiMnSb, ppdMnSb, pptMnSb) have attracted much attention due to their unique electronic and magnetic structures. Sppin-ppolarized band structure calculation ppredicts metallic behavior for the majority sppin states and semiconductor behavior for the minority sppin states. We have studied the electronic structures of these half-metallic Heusler alloys by core-level pphotoemission sppectroscoppy of Mn 2pp and 3s XppS sppectra. We found large intensities of Mn 2pp satellites and 3s exchange spplitting comppared with other metal Mn-alloys. These satellite structure can be understood by applying Anderson imppurity model. This fact supports the calculated sppin pprojected ppartial density of states which suggests that the valence electrons be highly sppin ppolarized near Fermi level and that the electrons involved with charge-transfer be mainly minority sppin ones which have semiconducting band structure. The trend of charge transfer energies Δ from ligands (Sb 5pp) to Mn 3d, obtained from our model fitting, is consistent with that calculated from sppin pprojected ppartial density of state. Also the trend of d-d electron correlation energies U calculated from Mn Auger line L3 VV by Mg $K\alpha$ source is comppatible with that resulted from our model fitting. We fitted the Mn 3s curve in the same way as for insulating Mn comppounds by using the same pparameters calculated from Mn 2pp curve fitting exceppt for the Coulomb interaction energy Q between core hole and d-electrons. The 3s sppectra were analyzed by combing the charge transfer model and a simpple model taking into account the configuration mixing effect due to the intra-shell correlation. We found that the exchange interaction between 3s hole and 3d electrons is mainly respponsible for the satellite of Mn 3s sppectra. This is consistent with the neutron scattering data, which suggests local 3d magnetic moment. We find that the XppS analysis results of Mn 2pp and 3s satellite structures of half-metallic Heusler alloys are very similar to those of insulating transition metal comppounds.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.41 no.5
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• pp.508-516
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• 1992

In this study, dielectric and piezoelectric properties of 0.05Pb(AlS12/3TWS11/3T)OS13T-0.95Pb(ZrS10.52TTiS10.48T)OS13T system ceramics were investigated with respect to the variations of MnOS12T and FeS12TOS13T additions amounts. The results obtained in this study are summarized as follows: 1. As the amounts of MnOS12T and FeS12TOS13T are increased, tetragonality(c/a) and apparent density were decreased but grain size was increased, also the limits of solubility were revealed because pores were formed at the amounts of 0.3wt% MnOS12T and 0.5wt% FeS12TOS13T. 2. AS the increasing of amounts of MnOS12T and FeS12TOS13T, the temperature of phase transition(TS1cT) was decreased, and pemeability had maximum value at the amount of 0.3wt% MnOS12T but were sharply decreasd for the increasing FeS12TOS13T amounts. 3. As the amounts of MnOS12T and FeS12TOS13T are increased, the electro-mechanical coupling factor(kS1pT) was decreased from 60% to 41%, 19% respectively, but mechanical quality factor(QS1mT) had maximum values 720 for amount of 0.3wt% MnOS12T and 320 the amount of 0.5wt% FeS12TOS13T.

• Metals and materials international
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• v.24 no.6
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• pp.1394-1402
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• 2018

This study investigates the mechanism of MnS precipitation on $Al_2O_3-SiO_2$ inclusions during the solidification of non-oriented silicon steel, especially the influence of the phase structures and sizes of the oxides on the MnS precipitation, by scanning electron microscopy and transmission electron microscopy coupled with energy dispersive spectrometry. The investigation results show that MnS tends to nucleate on submicron-sized $Al_2O_3-SiO_2$ inclusions formed by interdendritic segregation and that it covers the oxides completely. In addition, MnS can precipitate on micron-sized oxides and its precipitation behavior is governed by the phase structure of the oxides. The MnS embryo formed in a MnO-containing oxide can act as a substrate for MnS precipitation, thus permitting further growth via diffusion of solute atoms from the matrix. MnS also precipitates in a MnO-free oxide by the heterogeneous nucleation mechanism. Furthermore, MnS is less prone to precipitation in the $Al_2O_3$-rich regions of the $Al_2O_3-SiO_2$ inclusions; this can be explained by the high lattice disregistry between MnS and $Al_2O_3$.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.3
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• pp.99-114
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• 2012

Proxy Mobile IPv6 (PMIPv6) has received considerable attention between telecommunications and the Internet communities and does not require active participation of the Mobile Node (MN) by way of network-based mobility management. The PMIPv6 domain is studying establishment in progress to support extensively a number of MN by using a low handover latency. In this research, we are propose a novel 3S scheme for building Scalable and Secure and Seamless PMIPv6 domains. In the proposed scheme, all of Mobility Access Gateway (MAG) are acting as the Local Mobility Anchor (LMA) and composing a virtual ring with another MAG. General hashing is used in the efficient distribution-mapping between each MN and the MN's LMA of all MAGs. And, MAG and MN are authenticated using the symmetric key. Through mathematical analysis, we verifies the safety, scalability, and seamless service for 3S. Also, we're propose a handover procedure of 3S and show better than the existing schemes in terms of handover latency.

• Korean Journal of Materials Research
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• v.21 no.6
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• pp.295-298
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• 2011

ZnS:Mn, Dy yellow phosphors for White Light Emitting Diode were synthesized by a solid state reaction method using ZnS, $MnSO_4{\cdot}5H_2O$, S and $DyCl_3{\cdot}6H_2O$ powders as starting materials. The mixed powder was sintered at $1000^{\circ}C$ for 4 h in an air atmosphere. The photoluminescence of the ZnS:Mn, Dy phosphors showed spectra extending from 480 to 700 nm, peaking at 580 nm. The photoluminescence of 580 nm in the ZnS:Mn, Dy phosphors was associated with $^4T_1{\rightarrow}^6A_1$ transition of $Mn^{2+}$ ions. The highest photoluminescence intensity of the ZnS:Mn, Dy phosphors under 450 nm excitation was observed at 4 mol% Dy doping. The enhanced photoluminescence intensity of the ZnS:Mn, Dy phosphors was explained by energy transfer from $Dy^{3+}$ to $Mn^{2+}$. The CIE coordinate of the 4 mol% Dy doped ZnS:Mn, Dy was X = 0.5221, Y = 0.4763. The optimum mixing conditions for White Light Emitting Diode was obtained at the ratio of epoxy : yellow phosphor = 1:2 form CIE coordinate.

• Economic and Environmental Geology
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• v.42 no.5
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• pp.479-486
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• 2009

In natural environments, manganese (Mn) exists in the valence of +2, +3, and +4 and plays a pivotal role as a strong oxidant or reductant in the geochemical cycles of elements. Especially, Mn forms varying (oxyhydr)oxides. The oxidation state of structural Mn is characteristic to each oxide and is one of the most important factors controlling its geochemical behaviors such as solubility, sorption capacity, and redox potential. Therefore, it is important to elucidate processes governing Mn oxidation state in predicting the fate and transport of many redox sensitive elements in the environment. X-ray photoelectron spectroscopy (XPS) is a very useful method to determine the oxidation state of various elements in solid phases. In this study, the oxidation states of structural Mn in MnO, $Mn_2O_3$, $MnO_2$ were assessed based on the binding energy spectra of $Mn2p_{3/2}$ and Mn3s using XPS and were compared with those reported elsewhere. $Mn2p_{3/2}$ binding energies were determined as 640.9, 641.5, 641.8 eV for MnO, $Mn_2O_3$, $MnO_2$, respectively, which indicates that the binding energy increased with increasing Mn oxidation state. It was also noted that Ar etching may cause changes in electronic structure configuration on surface of the original sample.

• Korean Journal of Environmental Agriculture
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• v.29 no.1
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• pp.77-85
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• 2010

Reactive oxygen species (ROS) are very harmful to living organisms due to the potential oxidation of membrane lipids, DNA, proteins, and carbohydrates. transformed E.coli strain QC 871, superoxide dismutase (SOD) double-mutant, with three sequence variant MnSOD1, MnSOD2, and MnSOD3 manganese superoxide dismutase (MnSOD) gene isolated from wheat. Although all QC 871 transformants grown at $37^{\circ}C$ expressed mRNA of MnSOD variants, only MnSOD2 transformant had functional SOD activity. MnSOD3 expressed active protein when grown at $22^{\circ}C$, however, MnSOD1 did not express functional protein at any growing and induction conditions. The sequence comparison of the wheat MnSOD variants revealed that the only amino acid difference between the sequence MnSOD2 and sequences MnSOD1 and 3 is phenylalanine/serine at position 58 amino acid. We made MnSOD2S58F gene, which was made by altering the phenylalaine to serine at position 58 in MnSOD2. The expressed MnSOD2S58F protein had functional SOD activity, even at higher levels than the original MnSOD2 at all observed temperatures. These data suggest that amino acid variation can result in highly active forms of MnSOD and the MnSOD2S58F gene can be an ideal target used for transforming crops to increase tolerance to environmental stresses.

• Korean Journal of Materials Research
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• v.17 no.3
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• pp.137-141
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• 2007

A series of $Ca_{1-x}Sr_{x}S:Mn$ phosphors were synthesized by solid-state reactions. The emission peaks of $Ca_{1-x}Sr_{x}S:Mn$ is blue shifted front 605 to 570 nm with increasing Sr content. Since $Ca_{1-x}Sr_{x}S:Mn$. Mn phosphors exhibit strong absorption in region of 254 nm, the emission wavelength of a fluorescent lamp, these phosphors can be used as wavelength tunable emitting phosphors from reddish orange to yellow. We investigated the optical and structural properties of $Ca_{1-x}Sr_{x}S:Mn$ phosphors.

• Transactions of Materials Processing
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• v.31 no.6
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• pp.365-375
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• 2022

The microstructure and high-temperature plastic deformation behavior of the modified Al-0.7Mn alloy were investigated and compared with the conventional Al-0.3Mn (Al3102) alloy. α-Al (matrix) and Al₆(Mn, Fe) phases were identified in both alloys. As a result of microstructure observation, both alloys showed equiaxed grains, and Al-0.7Mn alloy showed larger grain size and higher Al₆(Mn, Fe) fraction than Al-0.3Mn alloy. High temperature compressive tests, the deformation temperatures of 410℃, 450℃, 490℃, 530℃ and strain rats of 10^-2/s, 10^-1/s, 1/s, 10/s, were conducted using Gleeble equipment. The flow stress values of Al-0.7Mn alloy were higher than that of Al-0.3Mn alloy at all strain rates and temperature conditions. Constitutive equations were presented using the flow stresses obtained from experimental results and the Zener-Hollomon parameter. In the true stress-true strain curves of the two alloys, the experimental and predicted values were in good agreement with each other. Based on the dynamic material model, eutectic deformation maps of Al-0.7Mn and Al-0.3Mn alloys were suggested, and the plastic instability region was presented. The modified Al-0.7Mn alloy showed a wider plastic instability region than that Al-0.3Mn alloy. Based on the process deformation maps, the MPE tube parts could be manufactured through the actual extrusion process using the suggested conditions.

• Electrical & Electronic Materials
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• v.10 no.2
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• pp.141-149
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• 1997

L $a_{0.7}$S $r_{0.3}$Mn $O_{3}$ powders were prepared by both GNP(Glycine-Nitrate Process) and solid state reaction method in various of calcination temperature(800-1000.deg. C) and time in air. Also, L $a_{0.7}$S $r_{0.3}$Mn $O_{3}$ cathode contacts on YSZ(Yttria-Stabilized Zirconia) substrate were prepared by screen printing and sintering method as a function of sintering temperature(1100-1450.deg. C) in air. Sintering behaviors have been investigated by SEM(Scanning Electron Microscope) and porosity measurement. Compositional and structural characterization were carried out by X-ray diffractometer and ICP AES(Inductively Coupled Plasma-Atomic Emission Spectrometry) analysis. Electrical characterization was carried out by the electrical conductivity with linear 4 point probe method. As the calcination period increased in solid state reaction method, L $a_{0.7}$S $r_{0.3}$Mn $O_{3}$ phase increased. Although L $a_{0.7}$S $r_{0.3}$Mn $O_{3}$ single phase was obtained only for 48hrs at 1000.deg. C, in GNP method it was easy to get single and ultra-fine L $a_{0.7}$S $r_{0.3}$Mn $O_{3}$ powders with submicron particle size at 650.deg. C for 30min. The particle size and thickness of L $a_{0.7}$S $r_{0.3}$Mn $O_{3}$ cathode contact by solid state reaction method did not change during the heat treatment, while those by GNP method showed good sintering characteristics because initial powder size fabricated from GNP method is smaller than that fabricated from solid state reaction method. Based on enthalpy change from thermodynamic data and ICP-AES analysis, it was suggested to make cathode contact in composition of (L $a_{0.7}$S $r_{0.3}$)$_{0.91}$ Mn $O_{3}$ which have little second phase (L $a_{2}$Z $r_{2}$ $O_{7}$) for high efficient solid oxide fuel cells applications. As (L $a_{0.7}$S $r_{0.3}$)$_{0.91}$Mn $O_{3}$ cathode contact on YSZ substrate was sintering at 1250.deg. C the temperature that liquid phase sintering did not occur. It was possible to obtain proper cathode contacts with electrical conductivity of 150(S/cm) and porosity content of 30-40%.m) and porosity content of 30-40%.