• 한국신재생에너지학회:학술대회논문집
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• 2007.11a
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• pp.125-128
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• 2007

In these recent years, low cost and stable battery electrode materials have been studied for HV/HEV application. Spinel cathode material $LiMn_2O_4$ is widely studied as a promising cathode material of lithium ion secondary batteries because of it is low cost, easily to be prepared and capable to be operated in high voltage range. In this study, $LiMn_2O_4$ was undergoing surface modification with spinel lithium titanium oxide by sol-gel method in order to enhance its capacity retention. Properties of both unmodified and surface-modified $LiMn_2O_4$ were characterized by XRD, SEM, particle size analyzer while their cycling performance was tested with charge and discharge tester.

• Korean Journal of Materials Research
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• v.14 no.12
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• pp.889-892
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• 2004

The synthesis of $Zn_{2}SiO_4:Mn^{2+}$ for PDP green phosphor by SHS(Self-propagating High temperature Synthesis method) was studied. The precursors were well mixed and cold compacted. And then, the green pellet was synthesized at high temperature through self-propagating high temperature zone. Because this reaction uses the heat resulted from the oxidation of Zn metal powder in this system, Zn/ZnO mole ratio is one of the most important reaction variable. Throughout several experiments, the optimal condition of Zn/ZnO mole ratio and Mn concentration are 1.2/0.8 and 0.05mo1e, respectively.

• Bulletin of the Korean Chemical Society
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• v.34 no.10
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• pp.3005-3012
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• 2013

The effect of Mn-promotion on high surface area Al-pillared montmorillonite (AlMMT) supported Co nanoparticles prepared by hydrothermal method have been investigated. A series of different weight% Mn-promoted Co nanoparticles were prepared and characterized by XRD, TPR, TGA, BET and SEM techniques. An increase in the surface area of MMT is observed with Al-pillaring. Fischer-Tropsch catalytic activity of the as prepared catalysts was studied in a fixed bed micro reactor at $225^{\circ}C$, $H_2/CO$ = 2 and at 1 atm pressure. The data showed that by the addition of Mn the selectivity of $C_1$ dropped drastically while that of $C_2-C_{12}$ hydrocarbons increased significantly over all the Mn-promoted Co/AlMMT catalysts. The $C_{13}-C_{20}$ hydrocarbons remained almost same for all the catalysts while the selectivity of $C_{21+}$ long chain hydrocarbons decreased considerably with the addition of Mn. The catalyst with 3.5%Mn showed lowest $C_{21+}$ and highest $C_2-C_{12}$ hydrocarbons selectivity due to cracking of long chain hydrocarbons over acidic sites of MMT.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.6
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• pp.976-982
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• 2007

This study investigated whether supplemental Cu, Fe, Zn, and Mn are needed in a practical diet for pullets. Four hundred and twenty females of an egg-laying strain (1-d-old, Lohmann Brown Layer) were randomly distributed into 4 groups, consisting of 7 replicates of 15 birds each. During the 18-week experimental period, chicks were given three basal diets in sequence, each with single or multiple Mn, Zn and Cu supplementation to improve the mineral balance gradually. In the Control, no Mn, Zn, and Cu were added; in the single Mn supplemented group (sMn) Mn was added to 120, 60, and 60 mg/kg for 1-6, 7-12, and 13-18 weeks of age, respectively; in the multiple Mn and Zn supplemented group (mMnZn), Mn was added to 180, 90, and 90 mg/kg and Zn was added to 120, 105, and 105 mg/kg for 1-6, 7-12, and 13-18 weeks of age, respectively; in the multiple Mn, Zn, Cu supplemented group (mMnZnCu), Mn, Zn, and Cu were added to the same multiple of basal Fe concentration relative to NRC (1994) recommendations. Energy and protein metabolizability were determined by subtracting energy/protein intake by energy/protein excretion (from both feces and urine) and dividing by energy/protein intake. There were no statistically significant differences between groups in terms of feed intake, final body weight or tibia length throughout the experiment. Optimal growth performance was observed in the Control, while adding trace minerals to basal diets tended to result in decreased productive performance. Protein metabolizability was increased by mMnZn and mMnZnCu treatments, but energy metabolizability was not affected. Concentrations of Mn, Zn, Cu in excreta varied greatly related to dietary content, and the retentions of Cu, Fe, Zn and Mn were all increased due to the improvement of mineral balance. Based on these results, it is suggested that the concentrations of Cu, Fe, Zn and Mn in typical basal diets used in this study were adequate for normal growth for pullets from 1 to 18 weeks of age.

• Korean Chemical Engineering Research
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• v.52 no.1
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• pp.52-57
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• 2014

The MCMB-$Li_4Ti_5O_{12}$ with core-shell structure was prepared by sol-gel process to improve low cycle capability of MCMB in this study. The electrochemical characteristics were investigated for hybrid capacitor using MCMB-$Li_4Ti_5O_{12}$ as the negative electrode and $LiMn_2O_4$, Active carbon fiber as the positive electrode. The electrochemical behaviors of hybrid capacitor using organic electrolytes ($LiPF_6$, EC/DMC/EMC) were characterized by charge/discharge, cyclic voltammetry, cycle and impedance tests. The hybrid capacitor using MCMB-$Li_4Ti_5O_{12}/LiMn_2O_4$ electrodes had better capacitance than MCMB hybrid systems and was able to deliver a specific energy with 67 Wh/kg at a specific power of 781 W/kg.

• Journal of Environmental Health Sciences
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• v.13 no.1
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• pp.67-71
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• 1987

This study was intended to investigate the content of Cu, Mn, Zn in the dried milk powders except infant formula milkpowder from January to March, 1986. The content of the trace metals was determined by Atomic Absorption Spectrophotometry. The results were as follows: 1. Averages of Cu, Mn, Zn in the total samples were Cu, 0.3043 ppm Mn, 0.5101 ppm Zn, 26.006 ppm. 2. Averages and ranges of Cu, Mn, Zu in the whole milk powder were Cu, 0.2483, 0.216 - 0.48 Mn, 0.552 ppm, 0.336 - 0.732 ppm Zn, 28.961 ppm, 7.5 - 51.9 ppm. 3. Averages and ranges of Cu, Mn, Zn in the skim milk powder were Cu, 0.4095 ppm, 0.3 - 0.54 ppm Mn, 0.6907 ppm, 0.348 - 0.84 ppm Zn, 38.381 ppm, 30.6 - 55.2 ppm. 4. Averages and ranges of Cu, Mn, Zn in the modified milk powder were Cu, 0.3459 ppm, 0.12 0.948 ppm Mn, 0.2414 ppm, 0.096 - 0.348 ppm Zn, 7.752 ppm, 1.2 - 17.002 ppm. 5. It showed the highest amount of Cu, Mn, Zu in the skim milk powder group than in the other group and the lowest amount of Cu in the whole milk powder group and Mn, Zn in the modified milk group.

• Bulletin of the Korean Chemical Society
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• v.19 no.11
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• pp.1175-1179
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• 1998

The aerobic reaction of 2-(acetylpyridine)-S-methyldithiocarbazate (acpy-mdtcH) and 2-(acetylpyridine)-N-phenylthiosemicarbazate(acpy-phTscH) with manganese(Ⅱ) acetate affords Mn(acpy-mdtc)2 and Mn(acpyphTsc)2, respectively. The spectroscopic data and X-ray structure of Mn(acpy-mdtc)2 are reported. Crystal data for Mn(acpy-mdtc)2; C18H20N6S4Mn, mol wt 503.58, monoclinic crystal system(P21/c) a=12.240(5) Å, b= 10.918(l) Å, c=17.651(3) Å, β=105.93(2), and V=2268(l) Å3, Z=4, 5071 data collected with 0°< 2θ < 52.64°, 2995 data with I > 3σ(I), R= 0.046, Rw= 0.065. The ligands act as tridentate NNS donors. The two Mn-S distances are not equal, and respectively 2.512(2) Å and 2.541(2) Å. The average Mn-N (azomethine) length, 2.242(5) Å, is slightly shorter than the average Mn-N (pyridyl) length, 2.262(5) Å. The coordination environment about MN(Ⅱ) center deviates considerably from octahedral geometry. The manganese(Ⅱ)-manganese(Ⅰ) and manganese(Ⅰ)-manganese(0) reduction potentials of Mn(acpy-mdtc)2 are ∼-l.71 and ∼-l.98 V while those of Mn(acpy-phTsc)2 are ∼-l.87 and ∼-2.11 V vs. Ag/Ag+ in dimethyl sulfoxide, respectively.

• Journal of the Korean Magnetics Society
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• v.12 no.2
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• pp.64-67
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• 2002

IrMn pinned spin valve (SV) films with stacks of Ta/NiFe/IrMn/CoFe/Cu/CoFe/NiFe/Ta were prepared by dc sputtering onto thermally oxidized Si (111) substrates at room temperature under a magnetic field of about 100 Oe. The annealing cycle number and temperature dependence of exchange coupling field (H$_{ex}$), magnetoresistance (MR) ratio, and coercivity (H$_{c}$) were investigated. By optimizing the process of deposition and post thermal annealing condition, we obtained the IrMn based SV films with MR ratio of 3.6%, H$_{ex}$ of 1180 Oe for the pinned layer. The H$_{ex}$ is stabilized after the second annealing cycle and it is thought that this SV reveals high thermal stability. The H$_{ex}$ maintained its strength of 600 Oe in operation up to 24$0^{\circ}C$ and decreased monotonically to zero at 27$0^{\circ}C$.

• Korean Journal of Materials Research
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• v.13 no.12
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• pp.839-845
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• 2003

The abrasion and impact wear resistance were investigated on the hardfacing weld dispersed with the recycled hard metal(HM). The HM was composed of the tungsten carbide(WC) reinforced metal matrix composite. The cored wire filled with the 25-35wt.% HM and 2-8wt.% of the alloying element, Fe-75Mn- 7C(FeMnC), was used for the gas metal arc(GMA) welding. By using the cored wire of the 25wt.% HM and FeMnC addition, the weld showed mostly constant wear loss for the abrasion as a function of the FeMnC content. This was due to the insufficient amount of the tungsten carbide formed during the GMA welding. The FeMnC addition to the 35wt.% HM did not improve the abrasion wear property since the amount of the tungsten carbide formed was decreased with respect to the FeMnC amount. The 6wt.% FeMnC addition to the 35wt.% HM exhibited the better impact wear resistance than the hardfacing weld by 40wt.% HM.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.12 no.1
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• pp.50-55
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• 1999

We have investigated the $LiMn_2O_4$system as an cathode material for lithium rechargeable batteries. $LiMn_2O_4$spinel oxides have been synthesized by a solid state methode. We varied sintering time at a fixed sintering temperature of 75$0^{\circ}C$. In order to investigate the electrochemical properties of prepared $LiMn_2O_4$we assembled three-electrode cells using the working electrode as active material and Li metal as the counter and reference electrodes. The electrolyte was 1 M LiPE$_{6}$-EC:DEC(1:1 by volume). The particle size of sample synthesized at 75$0^{\circ}C$ ranged about 60$\mu m$. The discharge capacity of a cell involving spinel $LiMn_2O_4$ increased with increasing sintering time.e.