• Transactions of the Korean hydrogen and new energy society
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• v.28 no.5
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• pp.447-452
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• 2017

A $Pd/TiO_2$ catalyst was prepared by a conventional impregnation method, and further characterized using transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and UV-Vis spectroscopy. The as-prepared material was employed to accelerate dehydrogenation of potassium formate in the presence of light at different temperatures. The $Pd/TiO_2$ catalyst showed distinct dehydrogenation activities, and particularly, the material exhibited a higher turnover frequency (TOF) of $2,097h^{-1}$ at $80^{\circ}C$ after 10 minutes in the presence of light compared to that (TOF of $1,477h^{-1}$) obtained in the absence of light. Numerous analytical techniques suggest that the increased dehydrogenation activity likely originates from light-excited electron and hole at the photocatalyst, i.e., $TiO_2$, in conjunction with metal-support interaction.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.582-585
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• 2015

In the aging society, TKRA is steadily increased because of joint diseases. Artificial joint used in TKRA generates metal artifacts in the MRI. Metal artifact may affect diagnosis. In study, We are going to minimize the effect of metal artifact to improve the value of diagnosis by changing the sequence and the type of artificial joint(Co-Cr, Ni-Ti). 1.5T AVANTO, plastic containers and each of the artificial joint (Normal, Co-Cr, NiTi) were used. After the artificial joints fixed in a paper cup was inserted in a plastic container of cylindrical, Signal intensity was measured. To obtain strong and uniform signal intensity, the plastic container was filled with water. We changed Sequences(T1 TSE, T2 TSE, PD TSE) and obtained an Axial image. After excepting the maximum and minimum values, We calculated the average of SNR, CNR and PSNR. Consequently, The SNR, CNR value of PD TSE are measured higher than these of T1 TSE, T2 TSE and The PSNR of Co-Cr is higher than this of Ni-Ti. The SNR of Co-Cr is similar to the SNR of normal comparing this of Ni-Ti. As a result, Using sequence of PD Tse and Co-Cr alloy is considered to be useful.

• Journal of Sensor Science and Technology
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• v.6 no.6
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• pp.476-482
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• 1997

A portable electronic nose system has been fabricated and characterized using an oxide semiconductor gas sensor array and pattern recognition techniques such as principal component analysis and back-propagation artificial neural network. The sensor array consists of six thick-film gas sensors whose sensing layers are Pd-doped $WO_{3}$, Pt-doped $SnO_{2}$, $TiO_{2}-Sb_{2}O_{5}-Pd$-doped $SnO_{2}$, $TiO_{2}-Sb_{2}O_{5}-Pd$-doped $SnO_{2}$ + Pd coated layer, $Al_{2}O_{3}$-doped ZnO and $PdCl_{2}$-doped $SnO_{2}$. The portable electronic nose system consists of an 16bit Intel 80c196kc as CPU, an EPROM for storing system main program, an EEPROM for containing optimized connection weights of artificial neural network, an LCD for displaying gas concentrations. As an application the system has been used to identify 26 carbon monoxide/hydrocarbon (CO/HC) car exhausting gases in the concentration range of CO 0%/HC 0 ppm to CO 7.6%/HC 400 ppm and the identification has been successfully demonstrated.

• Journal of Korea Foundry Society
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• v.22 no.6
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• pp.304-308
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• 2002

The new Cu-Zr-Ti-Ni-Pd amorphous alloy system has been introduced and manufactured using melt-spinning and Cu-mold die casting methods. Amorphous formability, the supercooled liquid region before crystallization and mechanical properties of the alloys were examined. The reduced glass transition temperature(Trg = Tg/Tm) and the supercooled liquid region(${\Delta}$Tx = Tx-Tg) of $Cu_{49}Zr_{30}Ti_{10}Ni_5Pb_6$ alloy were 0.620 and 57 K respectively. $Cu_{49}Zr_{30}Ti_{10}Ni_5Pb_6$ amorphous alloy was produced in the rod shape with 2mm diameter using the Cu-mold die casting. The hardness value of the amorphous bulk alloy was 432 DPN.

• Transactions of the Korean hydrogen and new energy society
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• v.21 no.4
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• pp.264-270
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• 2010

Recently, the most promising methods for high purity hydrogen production are membranes separation such as polymer, metal, ceramic and composites. It is well known that Pd and Pd-alloys membranes have excellent properties for hydrogen separation. However, it has hydrogen embrittlement and high cost for practical applications. Therefore, most scientists have studied new materials instead of Pd and Pd-alloys. On the other hand, TiN powders are great in resistance to acids and chemically stable under high operating temperature. In order to get specimens for hydrogen permeation, the TiN powders synthesized were consolidated together with Co, Ni powders by hot press sintering (HPS). During the consolidation of powders at HPS, heating rate was 10 K/min and the pressure was 10 MPa. It was characterized by XRD, SEM. Also, we estimated the hydrogen permeability by Sievert's type hydrogen permeation membrane equipment.

• Journal of the Microelectronics and Packaging Society
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• v.5 no.1
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• pp.7-18
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• 1998

In the flip chip interconnection on organic substrates using eutectic Pb/Sn solder bumps highly reliable Under Bump Metallurgy (UBM) is required to maintain adhesion and solder wettability. Various UBM systems such as 1$\mu$m Al/0.2$\mu$m Pd/1$\mu$m Cu, laid under eutectic Pb/Sn solder were investigated with regard to their interfacial reactions and adhesion proper-ties. The effects of numbers of solder reflow and aging time on the growth of intermetallic compounds (IMCs) and on the solder ball shear strength were investigated. Good ball shear strength was obtained with 1$\mu$m Al/0.2$\mu$m Ti/5$\mu$m Cu and 1$\mu$m Al/0.2$\mu$m ni/1$\mu$m Cu even after 4 solder reflows or 7 day aging at 15$0^{\circ}C$. In contrast 1$\mu$m Al/0.2$\mu$m Ti/1$\mu$m Cu and 1$\mu$mAl/0.2$\mu$m Pd/1$\mu$m 쳐 show poor ball shear strength. The decrease of the shear strength was mainly due to the direct contact between solder and nonwettable metal such as Ti and Al resulting in a delamination. In this case thin 1$\mu$m Cu and 0.2$\mu$m Pd diffusion barrier layer were completely consumed by Cu-Sn and pd-Sn reaction.

• Applied Chemistry for Engineering
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• v.26 no.3
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• pp.351-355
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• 2015

$Pd/TiO_2$ catalysts for aerobic benzyl alcohol oxidation were synthesized and eight different room temperature ionic liquids were used to control the palladium properties as active sites. $Pd/TiO_2$ particles were also calcined at 300, 400 and $500^{\circ}C$ to obtain an optimum catalyst. As the calcination temperature increased, the surface area and pore volume of catalyst decreased, but negligible changes were observed for the pore size of catalyst. However, the structural properties of catalyst varied with respect to the type of ionic liquids. Under identical reaction conditions, different catalytic activities were obtained depending upon the calcination temperature and type of ionic liquids. Mostly, the catalyst calcined at $400^{\circ}C$ showed higher catalytic activity than those at other temperatures. However, the catalyst prepared with 1-octyl-3-methylimidazolium hexafluorophosphate and 1-octyl-3-methylimidazolium trifluoromethanesulfonate showed good catalytic performance after calcination at $300^{\circ}C$. Among the catalyst, $Pd/TiO_2$ prepared with 1-octyl-3-methylimidazolium tetrafluoroborate and calcined at $400^{\circ}C$ showed the highest catalytic activity.

• Journal of the Korean Institute of Gas
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• v.11 no.1 s.34
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• pp.29-33
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• 2007

This study investigates the use of $TiO_{2},\;Pd,\;Pt$, and In which greatly improves a sensitivity to trimethylamine gas. The metal-$SnO_{2}$ thick films were prepared by screen-printing method onto $Al_{2}O_{3}$ substrates with platinum electrode. The sensing characteristics were investigated by measuring the electrical resistance of each sensor in a test box as a function of detecting gas concentration. This was then used to detect trimethylamine, dimethylamine, and ammonia vapours within the concentration range of 100-1000ppm. The gas sensing properties of metal-$SnO_{2}$ mixed thick films depended on the content and variety of metal. It was found that sensitivity and selectivity of the films dopped with 1 wt% Pd and 10 wt% $TiO_{2}$ for trimethylamin gas showed the best result at $250^{\circ}C$.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.11a
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• pp.433-434
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• 2010

• Korean Journal of Materials Research
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• v.9 no.3
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• pp.288-294
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• 1999

In the flip chip interconnection using solder bump, the Under Bump Metallurgy (UBM) is required to perform multiple functions in its conversion of an aluminum bond pad to a solderable surface. In this study, various UBM systems such as $Al 1\mu\textrm{m} / Ti 0.2\mu\textrm{m} / Cu 5\mu\textrm{m}, Al 1\mu\textrm{m} / Ti 0.2\mu\textrm{m} / Cu 1\mu\textrm{m}, al 1\mu\textrm{m}/Ni 0.2\mu\textrm{m} / Cu 1\mu\textrm{m} and Al 1\mu\textrm{m}/Pd 0.2\mu\textrm{m} / Cu 1\mu\textrm{m}$ for flip chip interconnection using the low melting point eutectic 63Sn-37Pb solder were investigated and compared to their metallurgical properties. $100\mu\textrm{m}$ size bumps were prepared for using an electroplating process. The effects of the number of reflows and aging time on the growth of intermetallic compounds(IMC) were investigated. $Cu_6Sn_5$ and $Cu_3Sn$ IMC were abserved after aging treatment in the UBM system with thick coper $(Al 1\mu\textrm{m}/Ti 0.2\mu\textrm{m}/Cu 5\mu\textrm{m})$. However only the $Cu_6Sn_5$ was detected in the UBM system with $1\mu\textrm{m}$ thick copper even after 2 reflow and 7 day aging at $150^{\circ}C$. Complete Cu consumption by Cu-Sn IMC growth gives rise to a direct contact between solder inner layer such as Ti, Ni and Pd, and hence to possibly cause reactions between two of them. In this study, however, only for the Pd case, IMC of PdSn. was observed by Cu consumption. UBM interfacial reactions with s이der affected the adhesion strength ot s이der balls after s이der reflow and annealing treatment.