• Clean Technology
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• v.15 no.1
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• pp.9-15
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• 2009

Catalytic hydrodechlorination of PCBs (polychlorinated biphenyls) included in the transformer oil was carried out to detoxify PCBs and to recycle the treated oil. Catalysts such as 0.98 wt% Pt and 0.79 wt% Pd on ${\gamma}$-alumina (${\gamma}-Al_2O_3$) support, 12.8 wt% Ni on ${\gamma}-Al_2O_3$, and 57.6 wt% Ni on silica-alumina ($SiO_2-Al_2O_3$) support were used for the catalytic hydrodechlorination. Various supercritical fluids such as carbon dioxide, propane and isobutane were used as reaction media. The effects of reaction temperature, reaction time, catalysts, and supercritical fluids on the catalytic hydrodechlorination were examined in detail. The detoxification degree increased in the order of Ni > Pd > Pt. This is possibly due to higher metal loading and larger metal size of the Ni catalyst. Below $175^{\circ}C,\;scCO_2$ was found as the most effective reaction media for the catalytic hydrodechlorination of PCBs included in the transformer oil.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.84.1-84.1
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• 2010

Since the discovery of the carbon nanotube(CNTs), they have attracted much attention because of unique properties that may impact many fields of science and technology. The considerable properties of CNTs include high surface area, outstanding thermal, electrical conductivity and mechanical stability. However, uniform deposition of Pt nanoparticles on carbon surface remains inaccessible territory because of the inert carbon surface. In this study, we prepared directly oriented CNTs on carbon paper as a catalyst support in cathode electrode. carbon surface was functionalized using aryl diazonium salt for increasing adhesion of Ni particles which is precursor for growing CNTs. For fabricate electrode, CNTs on carbon paper were grown by chemical vapor deposition using Ni catalyst and Pt nanoparticles were deposited on CNTs oriented carbon paper by polyol method. The performance was measured using Proton electrolyte Membrane Fuel Cell(PEMFC). The structure and morphology of the Pt nanoparticles on CNTs were characterized by Scanning electron Microscopy(SEM) and Transmission electron Microscopy (TEM). The average diameter of Pt nanoparticles was 3nm.

• Journal of the Korean Ceramic Society
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• v.27 no.7
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• pp.934-942
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• 1990

The quarternary system ceramics 0.5[yPb(Zn1/3Nb2/3)O3-(1-y)Pb(Ni1/3Nb2/3)O3]-0.5[xPbTiO3-(1-x)PbZrO3](PZN-PNN-PT-PZ) was fabricated by the columbite precursor method to obtain a stabilized perovskite structure and by conventional method to evaluate the efficiency of the former methd. Dielectric and piezoelectric properties were investigated and the stability of the perovskite phase was studied as a function of PZN and PT contents and firing temperature. In the samples prepared by the columbite precursor method, the pyrochlore phase, which is detrimental to both the dielectric and piezoelectric properties, was not observed in the absence of PZN, and electric properties were improved even when fabricated at low temperature. By adding PZN, some pyrochlore phase appeared and the morphotropic phase boundary of the samples shifted to more Zr-rich composition. The temperature dependence of piezoelectric constant decreased with the addition of PZN, due to the rising of the Curie point.

• Proceedings of the KIEE Conference
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• 2004.11a
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• pp.75-78
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• 2004

$Bi_{3.25}Eu_{0.75}Ti_3O_{12}$ (BET) thin films were deposited on the $LaNiO_3$ (LNO (100))/Si and Pt/Ti/$SiO_2$/Si substrates by the metal-organic decomposition method. Structural and dielectric properties of BLT thin films for the applications in nonvolatile ferroelectric random access memories were investigated. Both the structure and morphology of the films were analyzed by x-ray diffraction (XRD) and atomic force microscope (AFM). Even at low temperatures $650^{\circ}C$, the BET thinfilms were successfully deposited on LNO bottom electrode and exhibited (001) and (117) orientation. Compared with the Pt electrode films, the BET thin films on the LNO electrode annealed at $650^{\circ}C$ showed better dielectric constantsand remanent polarization. The BET thin films on the LNO electrode for the annealing temperature of $650^{\circ}C$, the remanent polarization Pr and coercive field were $45.6\;C/cm^2$ and 171 kV/cm, respectively.

• Journal of the Korean Chemical Society
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• v.54 no.1
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• pp.27-37
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• 2010

The reaction of 1,1'-bis(dimethylhydrosilyl)ferrocene with alkynes in the presence of a catalytic amount of ($C_2H_4$)Pt$(PPh_3)_2$ leads to the acyclic mixture of monohydrosilylated and/or dihydrosilylated compounds. But the analogous reactions in the presence of Ni$(PEt_3)_4$ catalyst yield monohydrosilylated compounds or dihydrosilylated products. The monohydrosilylated products were generated from the reactions of alkenes with the silylated ferrocene using nickel catalyst.

• Transactions of the Korean hydrogen and new energy society
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• v.30 no.3
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• pp.193-200
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• 2019

$RuO_2$, $PtO_2$, and various $(Ru,Pt)O_2$ colloidal solution were prepared using modified Watanabe method. Electrodes were manufactured by dipping of Ni mesh into the colloidal solution. Manufactured electrodes were characterized by XRD, SEM, and EDS. $(Ru,Pt)O_2$ electrodes showed $RuO_2$ crystal structure and high roughness. The hydrogen evolution reaction (HER) activities were evaluated by Linear Sweep Voltammetry. 1Ru2Pt electrode showed similar activity with commercial electrode, HER potentials are -0.9 V for both.

• Journal of the Korean Magnetics Society
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• v.11 no.2
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• pp.72-77
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• 2001

Top spin valve films with PtMn antiferromagnetic layers were deposited using a multi-target dc magnetron sputtering in (100)Si substrates overcoated with 500 $\AA$ of Al$_2$O$_3$. Firstly, the post-deposition annealing was performed at 270$\^{C}$ in a unidirectional magnetic field of 3 kOe to induce the crystallographic transformation of the PtMn layer from a fcc (111) to a fct (111) structure. Secondly, the spin valve films were annealed without magnetic fields and magnetic properties were measured. In Si/A1$_2$O$_3$ (500$\AA$)/Ta(50$\AA$)NiFe(40$\AA$)/CoFe(17$\AA$)/Cu(28$\AA$)/CoFe (30$\AA$)PtMn(200$\AA$)Ta(50$\AA$) top spin valve samples, the MR ratio decreased slowly with increasing annealing temperature up to 325$\^{C}$. But above 325$\^{C}$, the MR ratio decreased rapidly to 1%, due to a collapse of the exchange coupling between a antiferromagnetic layer and a pinned layer with increasing annealing temperature. Also above 325$\^{C}$, the exchange biased field rapidly decreased and the interlayer coupling field rapidly increased with increasing annealing temperature. A change in the interlayer coupling field was resulted from the increase in interface roughness due to Mn-interdiffusion through the grain boundaries. We confirmed the temperature in changing magnetic properties agreed well with the blocking temperature of PtMn based spin valve structure.

• Journal of the Korean Magnetics Society
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• v.8 no.3
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• pp.156-160
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• 1998

Crystal structures and magneto-optical properties of $(Mn_{0.5-Z}Sb_{0.5+Z})_{100-y}Pt_y$ (0$(Mn_{0.5-Z}Sb_{0.5+Z})_{100-y}Ag_y$ (0$^{\circ}C$ are C1b-type with fcc and NiAs-type with hcp, respectively. The MnSbAg films have a texture which the c-axis orientation is perpendicular to the film plane by annealing at 300 $^{\circ}C$ for less than 3 hours. The perpendicular anisotropy constants of the $Mn_{47.4}Sb_{47.5}Ag_{5.1}$ film annealed at 300 $^{\circ}C$ for 3 hours are $K_1=6.6{\times}10^5 \; erg/cm^3\;and\;K_2=1.9{\times}10^5\; erg/cm^3$. The Kerr rotation angle of MnSbPt films increases but that of MnSbAg film decreases by decreasing incident wavelength within the range of 700$\leq$ λ$\leq$1000 nm. High polar Kerr angles of 1.7$^{\circ}$ (λ =700 nm) and 0.6$^{\circ}$ (λ =1000 nm), 0.2$^{\circ}$ (λ =700 nm) and 0.97$^{\circ}$ (λ =1000 nm) have been obtained from $Mn_{41.1}Sb_{44,9}Pt_{14.0}$ and $Mn_{47.4}Sb_{47.5}Ag_{5.1}$ alloy films, respectively.

• Restorative Dentistry and Endodontics
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• v.30 no.6
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• pp.486-492
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• 2005

The purpose of this study was to compare the shaping ability of the two different Ni-Ti file systems and the two different engine systems in simulated canals. A total of four groups of each 10 were tested. Each group was instrumented with HeroShaper and Endo-Mate2 (Croup HE), HeroShaper and Tecnika (Croup HT), ProFile and Endo-Mate2 (Group PE), and ProFile and Tecnika (Croup PT). Canal preparation time was recorded. The images of pre- and post- instrumented root canals were scanned and superimposed. The amounts of increased width and centering ratio were measured and calculated at apical 1, 3 and 5mm levels. These data were statistically analyzed with one-way ANOVA and Duncan's multiple range test The results of this study were as fellows ; 1. Canal preparation time of HT group was the shortest (p<0.05). 2. The amount of increased canal width in HE group was significantly larger than PT group at apical 1mm level (p<0.05) At apical 3mm level, PT group was significantly smaller than other groups (p<0.05). At apical 5mm level, PE group was significantly larger than PT group (p<0.05). 3. The amount of centering ratio in HE group was significantly larger than other groups (p<0.05). At apical 5mm level, HT group was significantly larger than PE group and PT group (p<0.05). Under the condition of this study, torque-controlled endodontic motor is safer than no torque controlled motor, especially when the active file is used.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07b
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• pp.648-651
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• 2004

Pb0.5Sr0.5TiO3(PST) thin films were deposited on the LaNiO3 (LNO(100))/Si and Pt/Ti/SiO2/Si substrates by the alkoxide-based sol-gel method. Structural and dielectric properties of PST thin films for the tunable microwave device applications were investigated. The PST films, which were directly grown on the Pt/Ti/SiO2/Si substrates showed the random orientation. For the LNO/Si substrates, the PST thin films exhibited highly (100) orientation. Compared with randomly oriented films, the highly (100)-oriented PST thin films showed better dielectric constant, tunability, and figure of merit (FOM). The dielectric constant, tunability, and FOM of the highly (100)-oriented PST thin film increased with increasing annealing temperature due to the decrease in lattice distortion. The differences in dielectric properties may be attributed to the change in the film stress and the in-plane oriented Polar axis depending on the substrate was used. The dielectric constants, dielectric loss and tunability of the PST thin films deposited on the LNO/Si substrates measured at 1 MHz were 483, 0.002, and 60.1%, respectively.