• Journal of Hydrogen and New Energy
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• v.19 no.1
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• pp.35-40
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• 2008

Ni-based amorphous alloy ribbon was prepared by a single-roller melt-spinning technique. Palladium coating was found to enhance significantly the absorption/desorption behavior of hydrogen in amorphous alloy. The hydrogen permeability of a Pd-coated $(Ni_{60}Nb_{40}){_{100-X}}$TaX(x=5, 10) amorphous alloy was examined in the temperature range of $623{\sim}773K$, comparable with those of $Pd_{60}-Cu_{40}$ alloys. The permeated hydrogen flux was increased with increasing the temperature and the difference of hydrogen pressure between the feed side and permeates side of the membrane. The Ni-based amorphous alloys were characterized by X-ray diffractometry(XRD) and differential scanning calorimetry(DSC). The morphology of surface and roughness was observed by using scanning electron microscopy(SEM) and atomic force microscopy(AFM).

• Journal of Environmental Science International
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• v.18 no.3
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• pp.283-288
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• 2009

This is a study on the volatile organic compounds(VOCs) concentrator with zeolite adsorptive honey rotor and catalytic combustion system for abating VOCs emitted from printing industry. VOCs emitted from the printing industry is mainly caused by organic solvent of printing ink. The content of organic solvents in printing ink varies from 40% to 75% and its content in the gravure ink is higher than that in any other ink. The average concentrations of each VOCs are 139 ppm for toluene, 152.1 ppm for MEK, 256.9 ppm for methanol and 42.9 ppm for isopropyl alcohol. We used zeolite honeycomb for absorbent of VOCs concentrator and palladium for catalyst combustion system. This system abated over 96% of emitted total VOCs, 98% of toluene, 100% of MEK, 92% of methanol and, 100% of isopropyl alcohol. It is concluded that the low-leveled high-volume VOCs emitted from printing process were removed almost by concentrator with zeolite adsorptive honey rotor and catalytic combustion system.

• Journal of Technologic Dentistry
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• v.31 no.3
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• pp.15-20
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• 2009

The success of the porcelain fused to gold alloy restoration depends not only on the choice of materials but to a larger degree on the technical skills. The porcelain fused to metal(PFM) alloys containing gold are commonly use for dental purposes in dental laboratory. The gold-colored alloys contain primarily gold, platinum, palladium, and silver, with minimum amounts of such metals as tin, iridium, or titanium. The purpose of this study is on the metal-porcelain fusing layer in porcelain fused to high gold alloy Principal results are as follows. The hardness number(Hv) of PFG is respectively $140.2{\pm}12.6$ in as-casted, $164.3{\pm}14.3$ in heat-treated, $186.6{\pm}20.4$ in fired-treated. The formation of the fusing(intermediate) layer caused by components fusing the interface of porcelain and gold alloy. The main components of the fusing(intermediate) layer are Na, Al, Si, K, Zn, Zr and Ce. The intermediate layer formed by the 2nd firing is more larger than the intermediate layer formed by the 1st firing.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07b
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• pp.735-738
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• 2003

Downsizing electronics requires precision position control with an accuracy of sub-micron order, which demands development of ultra-fine displacive devices. Piezoelectric transducer is one of devices transferring electric field energy into mechanical energy and being capable for fine displacement control. The transducer has been widely used as fine Position control device Multilayer piezoelectric actuator, one of typical piezo-transducer, is fabricated by stacking alternatively ceramic and electrode layers several hundred times followed by cofiring process. Electrode material should be tolerable in the firing process maintaining at ceramic-sintering temperatures up to $1100{\sim}1300^{\circ}C$. Ag-Pd can be used as stable electrode material in heat treatment above $960^{\circ}C$. Besides, adding small quantity ceramic powder allow the actuator to be fabricated in a good shape by diminishing shrinkage difference between ceramic and electrode layers, resulting in avoidance of crack and delamination at and/or nearby interface between ceramic an electrode layers. This study presents synthesis of nano-oxide-added Ag/Pd powders and its feasibility to candidate material tolerable at high temperature. The powders were formed in a co-precipitation process of Ag and Pd in nano-oxide-dispersed solution where Ag and Pd precursors are melted in $HNO_3$ acid.

• The Journal of Korean Academy of Prosthodontics
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• v.30 no.1
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• pp.103-124
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• 1992

The purpose of this study was to investigate the effect on the fracture strength and color of ceramic by the design of the metal coping in ceramo metal crown. In this study, four types of ceramic crowns were made for fracture strength : standard ceramo metal crown, collariess ceramo metal crown, modified ceramo metal crown, and ceramic jacket crown. And three types of disk formed-specimens were made to compare the dentin shade owing to aluminous opaque powder and palladium alloy. Fracture strength was measured by universal testing machine(Instron Co. Ltd., U.S.A) and color was measured by color and color difference meter(Yasuda Seiki Seisakusho, Ltd., Japan). The results were as follows : 1. The fracture strength of ceramic was affected significantly by the design of metal coping in ceramo metal crown. The mean fracture strength(192.0 Kg) of standard ceramo metal crown was about 1.7 times higher than that(111.5 Kg) of collarless ceramo metal crown, and about 2.8 times higher than that(67.8 Kg) of ceramic jacket crown. 2. Modified ceramo metal crown that has metal band in the labio cervical had the lowest fracture strength. 3. Lightness, yellowness and redness of the dentin fired were decreased by the metal coping.

• Journal of Energy Engineering
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• v.19 no.1
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• pp.21-24
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• 2010

We present a novel electrochemical method to fabricate a single Pd nanowire based on direct current assisted dielectropheresis (DEP) process between two predefined metal electrodes. The electrochemical methods was investigated as functions of frequency and voltage for optimal growth conditions of Pd nanowire. The synthesized Pd nanowire have a good resistance of $1\;k{\Omega}$, diameters of several hundred nanometers on average and lengths of $8\;{\mu}m$. Finally, the single Pd nanowire was capable of detecting hydrogen in the concentration range from 100 to 2500 ppm with high sensitivity and response time, thus demonstrating its suitability for use as a hydrogen sensor.

• Journal of Power System Engineering
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• v.19 no.3
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• pp.11-15
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• 2015

In this paper, the multi-point hydrogen detection system based on the combination of the hetero-core optical fiber SPR hydrogen tip sensor and interrogator by pseudorandom noise (PN) code correlation reflectometry has been developed. In a light intensity-based experiment with an LED operating at 850 nm, it has been presented that a transmitted loss change of 0.32dB was induced with a response time of 25 s for 4% $H_2$ in $N_2$ in the case of the 25-nm Au, 60-nm $Ta_2O_5$, and 5-nm Pd multi-layers film. The proposed sensor characteristic shows excellent reproducibility in terms of loss level and time response for the in- and out- $H_2$ action. In addition, in the experiment for multi-point hydrogen detection, all sensors show the real-time response for 4% hydrogen adding with reproducible working. As a result, the real-time multi-point hydrogen detection could be realized by means of the combination of interrogating system and hetero-core optical fiber SPR hydrogen tip sensors.

• The Journal of Korean Academy of Prosthodontics
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• v.27 no.2
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• pp.201-218
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• 1989

The purpose of this study was to evaluate the influence of attachment technique on mechanical properties and microstructures of wrought wires. The wires tested in this study were precious metal wires: PGP (Platinum-Gold -Palladium), Elastic #12, Denture Clasp, Standard, Jelenko No. 2, Degulor-Klammerdraht, DM (Dong Myung) and base metal wire : Ticonium. Each wire was divided into three groups, and each group was heat treated as embedding, cast to, and soldering state. Heat treated sample was evaluated by tensile test, bending test, microhardness test, element analysis and microstructure test. The obtained results were as follows: 1. In tensile test, cast to and soldering procedures have an effect on wrought wire clasp as hardening heat treatment. 2. Maximum bending strength was significantly increased in Elastic #12, Denture Clasp, Standard, and DM in cast to procedure. 3. Ticonium showed the highest Victors hardness number, followed by PGP, and there was no significant difference in other wrought wires. In cast to and soldering procedure, Victors hardness number was significantly increased in precious wrought wires. 4. The precious wrought wire showed typical fibrous structure and this was disappeared in cast to and soldering procedure. But physical properties were not influenced by this phenomenon.

• Membrane and Water Treatment
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• v.4 no.4
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• pp.265-275
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• 2013

China is one of the countries with the highest reserves of coal bed methane (CBM) in the world. Likewise, the CBM industry is significantly growing in China. However, activities related to CBM development have led to more environmental problems, which include serious environmental damage and pollution caused by CBM-produced water. In this paper, the detailed characteristics of CBM-produced water in the southern Qinshui Basin were investigated and analyzed and compared with local surface water and coal mine drainage. Most of CBM-produced water samples are contaminated by higher concentration of total dissolved solids (TDS), K (Potassium), Na (Sodium) and $NH_4$. The alkalinity of the water from coalmines and CBM production was higher than that of the local surface water. The concentrations of some trace elements such as P (Phosphorus), Ti (Titanium), V (Vanadium), Cr (Chromium), Ni (Nickel), Zn (Zinc), Ge (Germanium), As (Arsenic), Rb (Rubidium), and Pd (Palladium) in water from the coalmines and CBM production are higher than the acceptable standard limits. The ${\delta}D$ and ${\delta}^{18}O$ values of the CBM-produced water are lower than those of the surface water. Similarly, the ${\delta}D$ values of the CBM-produced water decreased with increasing drainage time.

• The Journal of Korean Academy of Prosthodontics
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• v.31 no.2
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• pp.191-205
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• 1993

In order to compare the strength of soldered joints relative to the various sol dering method, soldering processes were performed using Palladium based ceramo-metal alloy(Bond-on 4)and Nickel-cromium alloy(Vera Bond). The obtained data include difference in strength between presoldering and postsoldering The data also contain difference among postsoldered groups for 3 difference soldering methods(torch, infrared. Oven) The following results were obtained : 1. For postsoldering with Pd alloy, the oven-using group showed the highest strength while the difference in strength between the torch-using group and the infrared machine group was negligible. 2. For Pd alloy with the torch method, postsoldering resulted in the higher strength than presoldering. 3. There was a negligible difference in strength between presoldering and postsoldering when Ni-Cr alloy with torch method is used. 4. Through microscopic study of the fractured surfaces, the torch-using group showed more porosity than both the oven-using and the infrared machine groups. 5. In terms of fracturing patterns, the oven-using group showed adhesive failure while both the torch and the infrared machine groups showed cohesive failure and cohesive-adhesive failure.