• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.12
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• pp.867-871
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• 2013

The Ti adhesion layers were deposited onto the glass substrate for transparent capacitors using $Bi_2Mg_{2/3}Nb_{4/3}O_7$ (BMNO) dielectric thin films. Graphene was transferred onto the Ti/glass substrate after growing onto the Ni/$SiO_2$/Si using rapid-thermal pulse CVD (RTPCVD). The BMNO dielectric thin films were investigated for the microstructure, dielectric and leakage properties in the case of capacitors with and without Ti adhesion layers. Leakage current and dielectric properties were strongly dependent on the Ti adhesion layers grown for graphene bottom electrode.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2014.11a
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• pp.174-175
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• 2014

We fabricated a Ni/C composite thick film on ${\alpha}-Al_2O_3$ substrate. A number of precipitations were observed on the film surface. Structural characterization was performed on the observed precipitations using transmission electron microscopy (TEM) with help of the elemental mapping, electron diffraction (ED) and ED simulation. The structural characterization revealed that the precipitation is ${\theta}-Al_2O_3$ having the space group of C2/m (Monoclinic).

• Journal of the Korean Chemical Society
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• v.19 no.5
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• pp.317-324
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• 1975

The adsorptions of gaseous $H_2O\;and\;D_2O\;on\;Na^+-,\;Ca^{2+}-,\;and\;Al^{3+}$ montmorillonites at various temperatures were undertaken. Break down of ir hydroxyl stretching bands into four Gaussian components was made by means of manual technique. Resonance theory of water to form silanol hydroxyl group was supported by $3625cm^{-1}$ band for OH and $2680cm^{-1}$ band for OD which depend on amounts of water adsorbed. The broad bands at about $3400 cm^{-1}\;and\;2475cm^{-1}$ were assigned to stretching band of silanol OH hydrogen bonded to adsorbed water. The prominent $3230 cm^{-1}$ band together with component around $2345 cm^{-1}$ were attributed to adsorbed $H_2O\;and\;D_2O$ respectively. The chemical nature of the hydrogen bonding between adsorbed water and neighboring surface OH was explained adequately in terms of electrostatic interaction.

• The Journal of the Petrological Society of Korea
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• v.20 no.1
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• pp.1-21
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• 2011

Eoil basalt in the Eoil basin and Yeonil basalt and its related volcanic rocks in Guryongpo and Daebo area were researched and analyzed to purse the tectonic settings and magma characteristics of those Tertiary volcanic rocks in the south-east Korean peninsula. It is highly suggested that zoning, resorption and sieve texture in plagioclase and reaction rim in pyroxene indicate unstable tectonic environments and complex volcanism in the study area. Volcanic rocks from Janggi basin are identified as basalt and basaltic andesite in TAS diagram and sub-alkaline series in terms of magma differentiation. $Na_2O$ and $K_2O$ show positive trend however FeO, CaO, MgO and $P_2O_5$ indicate negative trend in Harker variation diagram with $SiO_2$. Basaltic rocks from Eoil area are identified as calc-alkaline series in AFM diagram and show medium K series calc-alkaline in $K_2O-SiO_2$ diagram. Compatible trace elements of Co, Ni, V, Zn, and Sc in Yeonil basalt show negative trend with crystallization but incompatible trace element of Ba, Rb show positive trend with $SiO_2$ 0.81~1.00 of $Eu/Eu^*$ value suggests minor effect of plagioclase fractionation in Yeonil basaltic rocks. Plagioclase composition of Eoil basalt ranges from $An_{63.46-98.38}\;Ab_{1.62-32.96}\;Or_{0-3.58}$ (anorthite-labradorite) in core to $An_{40.89-82.44}\;Ab_{17.10-46.43}\;Or_{0-12.68}$ (bytownite-labradorite) in rim. $^{87}Sr/^{86}Sr$ and 143Nd;t44Nd ranges 0.704090~0.704717 and 0.512705~0.512822 respectively. Negative linear trends in 87Sr/86Sr and $^{143}Nd/^{144}Nd$ correlation diagram indicate that magma produced Yeonil basalt and basaltic andesite has been originated as partial melting product of mantle wedge by subducting Pacific plate affected by oceanic crust with less effect of continental crust indicating calc-alkaline magma characteristics.

• Proceedings of the Materials Research Society of Korea Conference
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• 2008.05a
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• pp.42.1-42.1
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• 2008

• Bulletin of the Korean Chemical Society
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• v.11 no.3
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• pp.231-235
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• 1990

The activation energy of dissociative adsorption of oxygen on polycrystalline nickel surface is calculated from adsorption isotherms obtained using X-ray photoelectron spectroscopy. Negative value of this activation energy (-5.9 kJ/mol) indicates that the adsorption takes place through an undissociated precursor state. An adsorption energy for this precursor state is calculated assuming the precursor state as a moleculary physisorbed state ($E_{ad}$ = -7.9 kJ/mol). Finally, an adsorption isotherm equation is derived as a function of the gas exposure, which agrees with the experimental isotherms reasonably good.

• Transactions on Electrical and Electronic Materials
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• v.18 no.6
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• pp.330-333
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• 2017

$Co_xMn_{3-x}O_4$ ($1.48{\leq}x{\leq}1.63$) ceramics were fabricated using the solid-state reaction method. Structural and electrical properties of specimens based on the composition ratio of Co were observed in order to investigate their applicability in NTC thermistors. All specimens showed a single spinel phase with a homogeneous tetragonal structure. The $Co_{1.57}Mn_{1.43}O_4$ specimen showed a maximum average grain size of approximately $6.47{\mu}m$. In all specimens, TCR properties displayed excellent characteristics of over $-4.2%/^{\circ}C$. The resistivity at 298 K and B-value of the $Co_{1.57}Mn_{1.43}O_4$ specimen were approximately $418{\Omega}-cm$ and 4300, respectively.

• Korean Journal of Materials Research
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• v.20 no.5
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• pp.241-245
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• 2010

One of the weak points of the Cr-doped SZO is that until now, it has only been fabricated on perovskite substrates, whereas NiO-ReRAM devices have already been deposited on Si substrates. The fabrication of RAM devices on Si substrates is important for commercialization because conventional electronics are based mainly on silicon materials. Cr-doped ReRAM will find a wide range of applications in embedded systems or conventional memory device manufacturing processes if it can be fabricated on Si substrates. For application of the commercial memory device, Cr-doped $SrZrO_3$ perovskite thin films were deposited on a $SrRuO_3$ bottom electrode/Si(100)substrate using pulsed laser deposition. XRD peaks corresponding to the (112), (004) and (132) planes of both the SZO and SRO were observed with the highest intensity along the (112) direction. The positions of the SZO grains matched those of the SRO grains. A well-controlled interface between the $SrZrO_3$:Cr perovskite and the $SrRuO_3$ bottom electrode were fabricated, so that good resistive switching behavior was observed with an on/off ratio higher than $10^2$. A pulse test showed the switching behavior of the Pt/$SrZrO_3:Cr/SrRuO^3$ device under a pulse of 10 kHz for $10^4$ cycles. The resistive switching memory devices made of the Cr-doped $SrZrO_3$ thin films deposited on Si substrates are expected to be more compatible with conventional Si-based electronics.

• Journal of Hydrogen and New Energy
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• v.34 no.5
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• pp.535-548
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• 2023

The intermittent nature of renewable energy is a challenge to overcome for safety and stable performance in water electrolysis systems linked to renewable energy. Oxygen removal using the catalyst is suitable for maintaining the oxygen concentration in hydrogen below the explosive level (4%) even in intermittent power supply. Metals such as Pd, Pt, and Ni are expected to be effective materials due to their hydrogen affinity. The oxygen removal performance was compared under high hydrogen concentration conditions by loading on γ-Al₂O₃ with high reactivity and large surface area. The characteristics of the catalyst before and after the reaction were analyzed through X-ray diffraction, transmission electron microscope, H₂-temperature programmed reduction, X-ray photoelectron spectroscope, etc. The Pd catalyst that showed the best performance was able to lower 2% oxygen to less than 5 ppm. Changes in catalyst characteristics after the reaction indicate that oxygen vacancies are related to oxygen removal performance and catalyst deactivation.

• Resources Recycling
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• v.29 no.3
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• pp.51-60
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• 2020

This study was carried out to get the optimum conditions for manufacturing high refractive glass beads from waste fluorescent lamp glass. Chemical composition, X-ray diffraction pattern, particle size distribution, refractive index of glass beads, and the effect of air mixing ratio and ejection rate were investigated. The obtained results are as follows. The X-ray diffraction pattern and chemical composition of glass beads made of waste fluorescent glass are similar to common glass except ReO₂ 0.0108 wt%, BaO 0.071 wt%, NiO 0.0039 wt% and CaO 7.8 wt% but 11.7 wt% of common glass. The glass beads made of waste fluorescent lamp glass have the narrower particle size distribution of and the higher refractive index than the glass beads made of common glass. The optimal conditions of kiln operation for manufacturing glass beads from waste fluorescent lamp glass are 20 m/sec of ejection rate, 1.7 of air mixing ratio, and 940℃ of temperature.