• Journal of Korean Society of Environmental Engineers
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• v.38 no.11
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• pp.603-610
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• 2016

This work studies the synthesis of birnessite (${\delta}-MnO_2$), a catalyst of oxidative-coupling reactions, from the powder of spent alkaline manganese batteries (SABP, <8 mesh) and evaluate its reactivity for 1-naphthol (1-NP) removals. Manganese oxides using commercial reagents ($MnSO_4$, $MnCl_2$) and the acid birnessite (A-Bir) by McKenzie method were also synthesized, and their crystallinity and reactivity for 1-NP were compared with one another. 96% Mn and 98% Zn were extracted from SABP by acid leaching at the condition of solid/liquid (S/L) ratio 1:10 in $1.0M\;H_2SO_4+10.5%\;H_2O_2$ at $60^{\circ}C$. From the acid leaching solution, 69% (at pH 8) and 94.3% (pH>13) of Mn were separated by hydroxide precipitation. Optimal OH/Mn mixing ratio (mol/mol) for the manganese oxide (MO) synthesis by alkaline (NaOH) hydrothermal techniques was 6.0. Under this condition, the best 1-NP removal efficiency was observed and XRD analysis confirmed that the MOs are corresponding to birnessite. Kinetic constants (k, at pH 6) for the 1-NP removals of the birnessites obtained from Mn recovered at pH 8 (${Mn^{2+}}_{(aq)}$) and pH>13 ($Mn(OH)_{2(s)}$) are 0.112 and $0.106min^{-1}$, respectively, which are similar to that from $MnSO_4$ reagent ($0.117min^{-1}$). The results indicated that the birnessite prepared from the SABP as a raw material could be used as an oxidative-coupling catalyst for removals of trace phenolic compounds in soil and water, and propose the recycle scheme of SAB for the birnessite synthesis.

• Journal of the Korean Society of Food Culture
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• v.20 no.4
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• pp.416-420
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• 2005

This study was carried out to make functional laver added with sericulture powder which have a effect of prevention adult diseases such as diabetes mellitus, hypertention, and obesity. In our lab. a lot of study have been performed about functional effect of sericulture(mulberry leaf, silkpeptide and silkworm) for examples decrease of serum cholesterol, triacylglyceride and control of serum glucose in rat. sericulture powder was prepared by pulverizing freeze-dried. Functional laver samples were prepared, and the sensory evaluation quality, physical characteristics and mineral contents of those were compared. In case of overal quality of sensory evaluation, silkpeptide powder laver was lower than other samples. The content of moisture of functional laver added with sericulture powder samples(control, sample 1, 2, 3) were 0.30, 0.98, 0.24 and 0.28%, respectively. The content of crude protein of functional laver added with sericulture powder samples were 40.50, 44.10, 56.75, and 62.50%, respectively. The content of crude fat of functional laver added with sericulture powder samples were 4.00, 4.10, 4.00 and 4.40%, respectively. The content of ash of functional Laver added with sericulture powder samples were 7.07, 7.53, 7.60 and 7.27%, respectively. The content of calcium of functional laver added with sericulture powder samples were 219, 253, 224 and 229mg/100g, respectively. The content of potassium of functional laver added with sericulture powder samples were 1879, 1919, 1890 and 1907mg/l00g, respectively. The content of iron of functional laver added with sericulture powder samples were 18.03, 18.23, 18.46 and 18.53mg/100g, respectively. The content of zinc of functional laver added with sericulture powder samples were 1.86, 4.47, 4.57 and 5.64mg/100g, respectively. The content of manganese of functional laver added with sericulture powder samples were 4.50, 8.50, 7.00 and 6.00 mg/100g, respectively. It was concluded that this functional laver added with sericulture powder is low calorie, high protein and high mineral health food which have a preventive effect of adult disease.

• Journal of Powder Materials
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• v.21 no.2
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• pp.131-136
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• 2014

Cathode materials and their precursors are prepared with transition metal solutions recycled from the the waste lithium-ion batteries containing NCM (nickel-cobalt-manganese) cathodes by a $H_2$ and C-reduction process. The recycled transition metal sulfate solutions are used in a co-precipitation process in a CSTR reactor to obtain the transition metal hydroxide. The NCM cathode materials (Ni:Mn:Co=5:3:2) are prepared from the transition metal hydroxide by calcining with lithium carbonate. X-ray diffraction and scanning electron microscopy analyses show that the cathode material has a layered structure and particle size of about 10 ${\mu}m$. The cathode materials also exhibited a capacity of about 160 mAh/g with a retention rate of 93~96% after 100 cycles.

• Nuclear Engineering and Technology
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• v.52 no.3
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• pp.647-653
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• 2020

Stainless steel is used commonly in nuclear applications for shielding radiation, so in this study, three different types of new stainless steel samples were designed and developed. New stainless steel compound ratios were determined by using Monte Carlo Simulation program Geant 4 code. In the sample production, iron (Fe), nickel (Ni), chromium (Cr), silicium (Si), sulphur (S), carbon (C), molybdenum (Mo), manganese (Mn), wolfram (W), rhenium (Re), titanium (Ti) and vanadium (V), powder materials were used with powder metallurgy method. Total macroscopic cross sections, mean free path and transmission number were calculated for the fast neutron radiation shielding by using (Geant 4) code. In addition to neutron shielding, the gamma absorption parameters such as mass attenuation coefficients (MACs) and half value layer (HVL) were calculated using Win-XCOM software. Sulfuric acid abrasion and compressive strength tests were carried out and all samples showed good resistance to acid wear and pressure force. The neutron equivalent dose was measured using an average 4.5 MeV energy fast neutron source. Results were compared to 316LN type stainless steel, which commonly used in shielding radiation. New stainless steel samples were found to absorb neutron better than 316LN stainless steel at both low and high temperatures.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.31 no.2
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• pp.8-14
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• 1999

A screening has been performed to find hyper-ligninolytic fungi, which degtrade beech and pine lignin extensively in order to broaden the understanding of the ligninolytic enzymes elaborated by various white-rot fungi. One hundred and twenty two ligninolytic strains were selected from decayed woods with a selective medium for screening ligninolytic wood-rotting fungi. Two of them, Phanerochaete sordida YK-624 and YK-472, showed much higher ligninolytic activity and selectivity in beech-wood degradation than typical lignin-degrading fungi, phanerochaete chrysosporium and Coriolus versicolor. They also degraded birch dioxane lignin and residual lignin in unbleached kraft pulp(UKP) much more extensively than P. chrysosporium and C. versicolor. During fungal treatment of beech wood-powder, the fungus strain P. sordida YK-624 showed higher activity of extracellular manganese peroxidase (MnP) in the medium than P. chrysosporium. It also showed MnP activity, which would not be lignin peroxidast during treatment of oxygen-bleached kraft pulp(OKP) and under enzyme-inducing conditin.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.212-213
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• 2018

The cementitious composites have been developed to satisfy various demands of the construction market. The conductive concrete, which is a carbon-based cementitious composite, was used for the deicing or the detecting the internal crack. The cement-based battery is a technology that applies the basic concept of the alkaline battery to these conductive concretes. The cementitious composites could have a function as batteries, through a mixing of anode and cathode, which were consist of the zinc and manganese dioxide powder. The carbon-based materials, which have a significant effect on electrical properties, could be considered as the main variable in cement-based batteries. Therefore, in this study, the effects of carbon-based materials were investigated. Two types of materials, including the Carbon black and Multi-walled carbon nanotube(MWCNT), were considered as the main variables. From the experiment results, the electrical characteristics such as resistance, voltage, and current were compared according to the age.

• Journal of the Korean institute of surface engineering
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• v.39 no.6
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• pp.288-294
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• 2006

Alloys of TiAl-Mn-(0, 5, 10)wt.% $Y_2O_3$ were prepared by a powder metallurgical route, and their oxidation behavior was studied at 800, 900 and $1000^{\circ}C$ in 1 atm of air. The scale formed on the alloys consisted of $TiO_2$ and $Al_2O_3$ oxides. During oxidation, Mn tended to diffuse outward, whereas oxygen diffused inward. The dispersoids of $T_2O_3$, which segregated at the matrix grain boundaries, acted as a diffusion channel for cations and oxygen ions, nucleation sites for oxides, and vacancy annihilation sites. $T_2O_3$ increased the scale thickness, but improved the scale adherence.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 1995.11a
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• pp.25-25
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• 1995

Liquid phase sintering of 90W-6Ni-4Mn alloy has been investigated as functions of sintering atmosphere, heating rate, and reduction temperature. The present work accounts for the thermodynamic oxidatiodreduction reactions of constituent powders of W, Ni and Mn. By discounting these reactions, the previous investigations would obtain only the alloy with large pores and the lowered relative sintered density, by the liquid phase sintering under a dry hydrogen atmosphere. the sintering cycle consisted of a rapid heating to reduction temperatures under high purity nitrogen atmosphere, and holding for 4 hours and sintering at $1260^{\circ}C$ for 1 hour under a dry hydrogen gas. The relative density of the sintered alloy increased with increasing heating rate. As the reduction temperature increased, the relative density increased to the lm theotical density at the duction temture above $1150^{\circ}C$. The mimsturcatre of sintered alloys has been analysed by a scanning election microscope. The sintered density was compared with those obtained from the other investigators. It was found that the reduction $1150^{\circ}C$ results in the lowered densification of 90W-6Ni-4Mn alloy. This is caused by the fact that reducing reactions of W and Ni oxides contained in W an Ni powders concomitantly leads to oxidizing reaction of Mn powder the oxidized Mn is hardly reduced at sintering temperature and thereby remains large pores in the alloy. It is concluded that the W-Ni-Mn alloy with full density can be obtained by the precise control of atmosphere, heating rate, and sintering temperature.

• Resources Recycling
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• v.22 no.3
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• pp.43-49
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• 2013

A study on the recovery of lithium and leaching behavior of NCM powder by hydrogen reduction for NCM system Li-ion battery scraps was investigated. The reductive rate was about 93% at $800^{\circ}C$ by hydrogen treatment. The lithium carbonate with 99% purity was manufactured by using $CO_2$ gas and washing method with water for NCM powder after hydrogen reduction. As a result of comparing the powders before and after the hydrogen reduction treatment for acid leaching behavior we obtained 32% enhanced leaching rate of cobalt, 45% enhanced leaching rate of nickel and the 90% leaching effect for manganese by hydrogen reduction at 2M $H_2SO_4$ concentration condition.

• Resources Recycling
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• v.22 no.4
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• pp.62-69
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• 2013

A study on the recovery of lithium and leaching behavior of NCM powder by carbon reduction for NCM-system Li-ion battery scraps was conducted. First of all, the oxide powders of NCM-system with layer structure were decomposed by carbon, lithium was converted to lithium carbonate by carbon reaction at above $600^{\circ}C$. The lithium carbonate powders with 99% purity were manufactured by washing method with water and concentration process for NCM powder after carbon reduction. The reaction yield was approximately 88% at $800^{\circ}C$ by carbon reduction. At this time, leaching efficiency at 2M sulfuric acid concentration was over 99% for cobalt, nickel and manganese.