• Journal of Technologic Dentistry
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• v.14 no.1
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• pp.23-43
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• 1992

Corrosion characteristics of four commerial gold-based dental alloys(C-1; Au75%, Ag13.9%, Pd3%, Cu & etc.,8.1%, C-2 ;Au 52.08, Ag 24%, Pd 5%, Cu & etc.,18.92, C-3 ; Au 53%, Ag 22%, Pd 5%, Pt 3% Cu & etc.,17%, C-4 ; Au 53%, Pd4, Pt1.5%, Ag & Cu & etc.,41.5%) and four experimental ternary Au-Ag-Cu alloys(E-1 ; Au 50%, Ag 30%, Cu 20%, E-2 ; Au 50%, Ag 20%, Cu 30%, E-3 ; Au 50%, Ag 10%, Cu 40%, E-4 ; Au 50%, Ag 40%, Cu 10%) were investigated by potentiodynamic polarization analysis and the structure was examined by optical microscope and SEM. All corrosion testing was conducted in 1% NaCl solution. The main results are as follows : 1. The corrosion resistence of commercial alloys was decreased in the order of C-1, C-3, C-4, C-2. C-2. 2. The E-1 and E-3 ternary alloys exhibits the higher corrosion resistence than E-2 and E-4 alloys. 3. The cast microstructure of alloys reveals dendrite morphology which shows the significant microsegregation caused by the difference in the diffusion rate between liquid and solid. 4. It is found that the surface corrosion products were mainly AgCl by X-ray diffraction results.

• Analytical Science and Technology
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• v.6 no.2
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• pp.217-223
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• 1993

Thin films of the Au/Cr, Au/Ni/Cr and Au/Pd/Cr systems were deposited on alumina substrates at ambient temperature and $250^{\circ}C$ in a high-vacuum resistance heating evaporator and annealed at $300^{\circ}C$, $450^{\circ}C$ and $600^{\circ}C$ for 1 hour in air, respectively. The film thicknesses of Au, Ni(or pd), and Cr were $1000{\AA}$, $300{\AA}$, and $50{\AA}$, respectively. The substrate temperature during deposition and the post-deposition annealing temperature affected the sheet resistance of thin-films due to the inter-diffusion of each layer. As a result of Auger depth profile analysis, in the Au/Cr system Cr already diffused out to Au surface during deposition at the substrate temperature of $250^{\circ}C$ and Au distribution changed after heat treatment. In the Au/Ni/Cr and Au/Pd/Cr systems, diffusion phenomena of Ni and Pd were found and especially Ni (approximately 45 at.%) diffused out to Au surface and oxidized.

• Food Science and Preservation
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• v.8 no.4
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• pp.367-373
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• 2001

In order to study the effect of modified atmosphere storage on extending shelf life of King Oyster mushroom was wrapped with PVC film and packed with 20$\mu\textrm{m}$polyolefin(PD941), and effects of temperature(0, 5, 10$^{\circ}C$) in packaging conditions on the respiration and keeping qualities were evaluated. Higher respiratory activity and weight loss were observed at higher temperature. The concentration of O$_2$and CO$_2$ of PVC wrap and polyolefin(PD941) packages for all showed 1∼2% and 10∼14%, respectively. Polyolefin(PD941) package wan superior to the PVC wrap packaging method in Hardness, Hunter L value, Hunter b value and sensory qualities, and reducing weight loss at 0$^{\circ}C$, 5$^{\circ}C$ and 10$^{\circ}C$ compared to PVC wrap. It was found that the optimum shelf-life period of King Oyster mushroom packaged by PVC wrap was estimated to be 50, 28 and 12 days at 0, 5 and 10$^{\circ}C$, respectively, and 50, 32 and 21 days in Polyolefin(PD941).

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.777-780
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• 2009

본 연구에서는 연료전지에의 응용을 위한 저가격의 무산소, 상온동작 가능한 센서구조를 설계, 제작하고 특성을 평가하였다. 연료전지의 수소 농도를 측정하기 위해서는 50ppm에서 5% 이상까지 넓은 범위를 감지할 수 있는 수소센서의 성능이 매우 중요하다. 이러한 특성과 상용화를 위해 가격 경쟁력을 갖는 수소센서로서, 수소흡착에 따른 Pd의 저항변화 특성을 이용한 센서 구조에 대하여 연구하였다. 높은 저항치를 갖는 Pd 후막 구조설계를 통하여 저항 감소형의 센서를 제작하여 특성평가를 하였다. 저가형으로 설계 제작된 Pd 수소센서는 50~20000ppm 범위에서 감지특성을 나타내었으며, 약 40sec의 응답속도를 보였다.

• Journal of the Ergonomics Society of Korea
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• v.16 no.1
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• pp.85-96
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• 1997

This article reviews the effects of VDT tasks on multiple resources for processing and storage in short-term working memory. MD and PD method were introduced toevaluate the modalities (auditory-visual) in the multiple resources model. The subjects conducted 2 sessions of 50 minites VDT tasks. Before, between and after VDT tasks, MD, PD task performance scores and CFF(critical flicker frequency0 values were measured. The review suggested that the modalities of human information processing in working memory were affected by VDT tasks with different task contents.

• Biomedical Science Letters
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• v.17 no.4
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• pp.291-295
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• 2011

PD98059 is the specific inhibitor of extracellular signaling-regulated kinase (ERK) kinase (MEK). ERK is involved in a mitogen-activated protein kinase (MAPK) cascade controlling cell growth and differentiation. Although the inhibition of ERK is known to induce cell death in various cell lines, this effect is still controversial and the role of PD98059 on the death of HeLa $S_3$ cells, a subclone of the cervical cancer cell line, is not well understood. The apoptosis of HeLa $S_3$ cells increased after the treatment of 50 ${\mu}M$ PD98059. The induction of apoptosis by PD98059 was occurred in a time- and a dose-dependent manners. The expression of Bcl-2 was reduced in accordance with decrease of ERK2 expression. Taken together, these results indicate that PD98059 has a cytotoxicity in HeLa $S_3$ cells and it may be used as a potential target for the treatment of cervical cancer.

• Journal of Ginseng Research
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• v.17 no.3
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• pp.187-195
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• 1993

We have examined the functional role of central dopaminergic processes on the behavioral pharmacological effects induced by psychotropics and red ginseng saponins of normal rats and compared with that of brain damaged rats. Desipramine and clomipramine produced, a significant depression of the locomotor activity in normal rats, but in brain damaged rats, they did not have any effect throughout the experimental period of 4 hours. Total saponin (50~200 mg/kg), PT (25~50 mg/kg), PD (25~50 mg/kg), $Rg_1$(12.5~25 mg/kg), $Rb_1$ (12.5~50 mg/kg) did not change, and high concentrations of PT (100 mg/kg), PD (100 mg/kg) and $Rg_1$ (50 mg/kg) showed a significant decrease in the locomotor activity of one hour after administration but total saponin (100 mg/kg), PD (25~50 mg/kg), Rgl (12.5 mg/kg), $Rb_1$ (12.5 mg/kg) markedly increased the locomotor activity of four hour after administration in normal rats. On the other hand, total saponin (50 mg/kg), PT (100 mg/kg) and PD (100 mg/kg) Produced a prominent stimulation of the locomotor activity in brain damaged rats. These results suggest that the inhibition of the locomotor activity induced by antidepressants was not affected by the sensitivity of cerebral DA system, whereas red ginseng saponin showed antifatigue effect and also the stimulation of the locomotor activity induced by red ginseng saponin was mediated by the inhibition of cerebral DA system. These psychotropic action of red ginseng saponins could be responsible for the beneficial effects on conditions of fatigue and decreased alertness.

• Journal of Magnetics
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• v.15 no.2
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• pp.45-50
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• 2010

We investigated the magnetism of vanadium monolayers on a Pd(001) surface. The electronic structure and the magnetic properties of the V/Pd(001) system were determined with the use of the full-potential linearized augmented plane-wave method within the general gradient approximation. Three magnetic configurations were studied: non-, ferro-, and antiferromagnetic. From the total energy calculations, we found that the V/Pd(001) system is the most stable in the antiferromagnetic configuration. The importance of relaxation on the magnetic properties of the systems was also studied. It was found that the Pd(001) surface covered with a V monolayer undergoes considerable relaxation in which the spacing between Pd layers increases in all three magnetic configurations. Contrary to the Pd interlayer spacing, the distance between the V overlayer and the topmost Pd layer is reduced. The interlayer spacing between the V overlayer and the Pd surface layer is the largest for the antiferromagnetic configuration. In the relaxed antiferromagnetic structure, the magnitude of the calculated magnetic moments on the V atoms was $1.31\;{\mu}_B$. The presence of the vanadium monolayer does not affect the paramagnetic properties of the Pd(001) surface.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.482-488
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• 2001

Platinum group metals (pgm) are useful to many industries such as chemical, dental and medical, petroleum, refining, electrical and electronic, and automotive. Researchers at the South Dakota School of Mines and Technology and PGM Recovery Ltd. have developed jointly an environmentally sound and metallurgically efficient process for extracting these metals from secondary sources. Once these metals have been dissolved in the leach liquor, the individual metals mainly platinum, palladium, and rhodium, should be separated in order to recover the individual metals with high purity. During this investigation, solvent extraction has been chosen as the method used to achieve the separation and extraction of platinum, palladium, and rhodium from the leach liquor. There were three solutions used throughout this procedure: 1) Synthetic solution (200 ppm Pt 80 ppm Pd 20 ppm Rh; 300 ppm Pt, 180 ppm Pd 50 ppm Rh), and 2) Auto catalyst leach liquors (100 ppm Pt, 30 ppm Pd, 20 ppm Rh). The solvents investigated included Lix 84(2-hydroxy-5-nonylacetonphenone oxime in a mixture with 5-dodecylsalicyloxime), Lix 84-I, ACORGA CLX-50 (diester of pyridine 3,5 dicarboxylic acid), and di-hexyl sulfide. The extraction values achieved using ACORGA CLX-50, Lix 84, and Lix 84-I were respectively Pt (25%, 0% 0%), Pd (100%, 99.8%, 95.3%), and Rh (99.1%, 35.5%, 4.25%). The stripping processes for the Lix 84, and Lix 84-I were proven to be more involved than others. The solutions were required to be simultaneously heated and stirred. The percentages acquired through these processes yielded unsatisfactory results. The stripping procedure for the ACORGA CLX-50 was easier to execute, yet the percentage recovered from this process was also unsatisfactory. Overall the di-hexyl sulfide has proved to be the most successful organic for this procedure. The average percent extracted for palladium was excellent with 99.9% - 100% with very little Platinum and rhodium extracted. The ability of stripping palladium in ammonia solution was also found to be excellent.

• Journal of the Korean Ceramic Society
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• v.50 no.4
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• pp.251-256
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• 2013

Multiwalled carbon nanotubes (MWCNTs) modified with Pd and $TiO_2$ composite catalysts were synthesized by the sol-gel method followed by solvothermal treatment at low temperature. The chemical composition and surface structure were characterized by X-ray diffraction (XRD), energy-dispersive X-ray (EDX) spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Photocatalytic recycle degradation experiments were carried out under both UV and visible light irradiation in the presence of MWCNT/$TiO_2$ and Pd-MWCNT/$TiO_2$ composites. As expected, the nanosized Pd-MWCNT/$TiO_2$ photocatalysts had enhanced activity over the non Pd treated MWCNT/$TiO_2$ material in the degradation of a rhodamine B (Rh.B) solution. An increase in photocatalytic activity was observed and attributed to an increase in the photo-absorption effect by MWCNTs and the cooperative effect of Pd and $TiO_2$ nanoparticles. According to the recycled results, the as-prepared Pd-MWCNT/$TiO_2$ sample had a good effect on it.