• Bulletin of the Korean Chemical Society
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• v.31 no.2
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• pp.355-359
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• 2010

A $Li[Co_{1/3}Ni_{1/3}Mn_{1/3}]O_2$ cathode was modified by applying a $ZrF_x$ coating. The surface-modified cathodes were characterized by XRD, SEM, EDS, TEM techniques. XRD patterns of $ZrF_x$-coated $Li[Co_{1/3}Ni_{1/3}Mn_{1/3}]O_2$ revealed that the coating did not affect the crystal structure of the parent powder. SEM and TEM images showed that $ZrF_x$ nano-particles were formed as a coating layer, and EDS data confirmed that $ZrF_x$ distributed uniformly on the surface the powder. Capacity retention of coated samples at high C rates was superior to that of pristine sample. However, as the coating concentration increases beyond the optimum concentration, the rate capability was deteriorated. Whereas, as the increase of coating concentration to 2.0 wt %, the cyclic performances of the electrodes under the severe conditions (high cut-off voltage, 4.8 V, and high measurement temperature, $55^{\circ}C$) were improved considerably.

• 한국신재생에너지학회:학술대회논문집
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• 2007.06a
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• pp.133-136
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• 2007

Perovskite-structured samarium strontium cobaltite (SSC), which is mixed ionic electronic conductor (MIEC), is considered as a promising cathode material for intermediate temperature-operating solid oxide fuel cell (SOFC) due to its high electrocatalytic property. Cathode material containing cobalt (Co) is unstable at high temperature and has a relatively high thermal expansion property. In this paper, Sm-Sr-(Co,Fe,Ni)-O system with perovskite and spinel structures was investigated in terms of electrochemical property and thermal expansion property, respectively. Area specific resistance (ASR) was measured by ac impedance spectroscopy to investigate the electrochemical property of cathode, and thermal expansion coefficient (TEC) was measured by using dilatometer. Micro structure of cathode was observed by scanning electron microscopy. Perovskite-structured $Sm_{0.5}Sr_{0.5}CoO_{3-\delta}$ showed the ASR of $0.87{\Omega}/cm^{2}$, and $Sm_{0.5}Sr_{0.5}NiO_{3-\delta}$, which actually has a spinel structure, showed the lowest TEC value of $13.3{\times}10^{-6}/K$.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2003.10a
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• pp.110-111
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• 2003

• Korean Journal of Crystallography
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• v.10 no.1
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• pp.33-38
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• 1999

The complex [Ni(L2)(H2O)]Cl·H2O (1) (L2=3,14-dimethyl-2,6,13,17-tetraazartricyclo [14,4,01.18,07.12]docosane-N-acetic acid) has been synthesized and characterized by X-ray crystallography. 1 crystallizes in the triclinic system, space group P, with a=11.274(1), b=13.851(1), c=17.159(6) , α=90.24(2), β=101.10(2), γ=92.11(1)o V=2682.5(11) 3, Z=4, R1=0.042 and wR2=0.111 for 9432 observed reflections with [I>2σ(I)]. The central nicke(II) ion is six-coordinated octahedral geometry with bonds to the four amine nitrogen atoms the carboxylic oxygen atom of the macrocyclic ligand and to the water molecule occupying a position trans to the pendant arm.

• Journal of Surface Science and Engineering
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• v.27 no.4
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• pp.193-206
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• 1994

A wear behavior of electroless (Ni-P-X, X: SiC, $Al_2O_3$, Diamond) composite coating layers, formed under various conditions on commerical grade low carbon steel, has been investigated using Taber abrasion tester and scanning electron microscope. Several factors, which are type of particles, co-deposited content, particle size, distribution of particles and heat-treatment, influenced the wear resistance. The wear resistance of the composited coating layers after heat-treatment at $400^{\circ}C$ for 1 hr was increased 70 times with diamond, 15 times with SiC and 8 times with $Al_2O_3$, compared with the electroless nickel plating layer without heat-treatment.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.11a
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• pp.334-337
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• 2002

In this study, the microstructure, dielectric and piezoelectric properties of $0.15Pb(Ni_{1/3}Nb_{2/3})O_3-0.85(PbZr_{0.5}Ti_{0.5})O_3$(0.15PNN-0.85PZT) ceramics having compositions near the morphotropic phase boundary(MPB) was investigated with respect to the variation of $Y_2O_3$ and $Ga_2O_3$ addition amount. The dielectric properties increased and piezoelectric properties decreased with increasing the amount of $Ga_2O_3$. The solubility limit of $Y_2O_3$ is 0.5mol% in this system. The electro-mechanical coupling factor$(K_p)$ and dielectric constant(${\varepsilon}_r$) were 58.6% and 1755 when the amount of $Y_2O_3$ are 0.5mol%.

• Journal of the Korean Electrochemical Society
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• v.16 no.3
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• pp.151-156
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• 2013

As the cathode material for li-ion battery, $LiNi_{0.5}Mn_{0.3}Co_{0.2}O_2$ were synthesized by supercritical hydrothermal method and calcined $850^{\circ}C$ and $900^{\circ}C$ for 10hrs in air. The effect of temperature in the heat treatment on the powder and its performance were studied of xray diffraction pattern, SEM-image, physical properties and electrochemical behaviors. As a result, calcined at $900^{\circ}C$ material particle size more increase than calcined at $850^{\circ}C$ material, especially shows excellent electrochemical performance with initial reversible specific capacity of 163.84 mAh/g (0.1C/2.0-4.3V), 186.87 mAh/g (0.1C/2.0-4.5V) and good capacity retention of 91.49% (0.2C/2.0-4.3V) and 90.36% (0.2C/2.0-4.5V) after 50th charge/discharge cycle.

• Clean Technology
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• v.21 no.3
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• pp.184-190
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• 2015

Most of LNT catalysts use noble metals such as Pt for low temperature NO_x oxidation but there is an economic weakness. For the purpose of overcoming this, this study is to develop DeNO_x catalyst for LNT excluding PGM (platinum group metal) such as Pt, Pd, Rh, etc. To do so, Al/Co/Ni catalyst selected as a preliminary test is used to study fundamental property and NO_x’s conversion according to calcined temperature. Ultimately, that is, Al/Co/Ni mixed metal oxide which does not use PGM is selected and physicochemical characterization is performed by way of XRD, EDS, SEM, BET and ramp test and NO_x conversion is also analyzed. This study shows that all samples consist of mixed oxides of spinel structure of Co₂AlO₄ and NiAl₂O₄ and have enough pore volume and size for redox. But as a result of NH₃-TPD test, it is desired that calcined temperature needs to be maintained at 700 ℃ or lower. Also only samples which are processed under 500 ℃ satisfied NO and NO_x conversion simultaneously through ramp test. Based on this study’s results, optimum calcined temperature for Al/Co/Ni=1.0/2.5/0.3 mixed metal oxide catalyst is 500 ℃.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.216-216
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• 2009

$(Ni_{1-x-y}Zn_xCu_y)Fe_2O_4(x=0.45,\;0{\leq}y{\leq}0.3)$ was synthesized by conventional ceramic processing, and the sintering behavior and the magnetic properties of which were studied as functions of CuO content and sintering temperature. Both the densification and the grain growth rates were significantly enhanced with the increase of CuO content, while abnormal grain growth occurred when the samples of $y{\geq}0.2$ were sintered above $950^{\circ}C$. Saturation magnetization and coercive field were mainly influenced by the densification and grain growth of the specimens, respectively.

• Advances in nano research
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• v.10 no.1
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• pp.77-90
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• 2021

In the present study, novel chitosan coated magnetic magnetite (Fe3O4) nanoparticles were successfully biosynthesized from mushroom, Agaricus campestris, extract. The obtained bio-nanocomposite material was used to investigate ultra-fast and highly efficient for removal of Ni2+ ions in a fixed-bed column. Chitosan was treated as polyelectrolyte complex with Fe3O4 nanoparticles and a Fungal Bio-Nanocomposite Material (FBNM) was derived. The FBNM was characterized by using X-Ray Diffractometer (XRD), Scanning Electron Microscopy-Energy Dispersive X-Ray Spectroscopy (SEM-EDS), Fourier Transform Infrared spectra (FTIR) and Thermogravimetric Analysis (TGA) techniques and under varied experimental conditions. The influence of some important operating conditions including pH, flow rate and initial Ni2+ concentration on the uptake of Ni2+ solution was also optimized using a synthetic water sample. A Central Composite Design (CCD) combined with Response Surface Modeling (RSM) was carried out to maximize Ni2+ removal using FBNM for adsorption process. A regression model was derived using CCD to predict the responses and analysis of variance (ANOVA) and lack of fit test was used to check model adequacy. It was observed that the quadratic model, which was controlled and proposed, was originated from experimental design data. The FBNM maximum adsorption capacity was determined as 59.8 mg g-1. Finally, developed method was applied to soft drinks to determine Ni2+ levels. Reusability of FBNM was tested, and the adsorption and desorption capacities were not affected after eight cycles. The paper suggests that the FBNM is a promising recyclable nanoadsorbent for the removal of Ni2+ from various soft drinks.