• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.795-798
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• 2002

Replacing Pb-free glass composition for the dielectric materials is expected in PDP industry. In this study, phosphate glasses, $P_2O_5$- ZnO- SnO (PZS), $P_2O_5$-ZnO-BaO (PZB) were selected for a new transparent dielectric. Thermal properties (Tg, CTE) were measured with differential thermal analyzer and thermal mechanical analyzer. The glass transition of the glasses was ranged at $365{\sim}405^{\circ}C$ for the PZS system and $5.9{\sim}9.5{\times}\;10^{-6}$ of thermal expansion were found. The PZB system showed $445{\sim}470^{\circ}C$ of glass transition. Thus, the glass compositions would be a potential candidate for a transparent dielectric layer in plasma display panel.

• Journal of Soil and Groundwater Environment
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• v.12 no.4
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• pp.72-77
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• 2007

Soil contamination by heavy metals was environmental concern due to its effect on human. In this study, monopotassium phosphate $(KH_2PO_4)$ used as phosphate source to remediate the contaminated soil with heavy metals and factors such as reaction time, initial concentration and pH of phosphate solution, species of heavy metal (lead, cadmium, zinc) and particle size were controlled. Heavy metals were removed in the order Pb > Zn > Cd and the maximum effectiveness was achieved for Pb. The removal efficiency of lead was from 95% to 100% and occurred rapidly occurred during 10 minutes. Mechanism of lead immobilization is dissolution of phosphate and the forming of a new mineral with phosphate having extremely low solubility.

• Journal of Microbiology and Biotechnology
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• v.30 no.1
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• pp.118-126
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• 2020

Silicon and phosphorus are elements that are beneficial for plant growth. Despite the abundant availability of silicate and phosphate in the Earth's crust, crop nutritional requirements for silicon and phosphorus are normally met through the application of fertilizer. However, fertilizers are one of the major causes of heavy metal pollution. In our study, we aimed to assess silicate and phosphate solubilization by the bacteria Enterobacter ludwigii GAK2, in the presence and absence of phosphate [Ca₃(PO₄)₂] or silicate (Mg₂O₈Si₃), to counteract cadmium stress in rice (Oryza sativa L). Our results showed that the GAK2-treated rice plants, grown in soil amended with phosphate [Ca₃(PO₄)₂] or silicate (Mg₂O₈Si₃), had significantly reduced cadmium content, and enhanced plant growth promoting characteristics including fresh shoot and root weight, plant height, and chlorophyll content. These plants showed significant downregulation of the cadmium transporter gene, OsHMA2, and upregulation of the silicon carrier gene, OsLsi1. Moreover, jasmonic acid levels were significantly reduced in the GAK2-inoculated plants, and this was further supported by the downregulation of the jasmonic acid related gene, OsJAZ1. These results indicate that Enterobacter ludwigii GAK2 can be used as a silicon and phosphorus bio-fertilizer, which solubilizes insoluble silicate and phosphate, and mitigates heavy metal toxicity in crops.

• Journal of the Korean Vacuum Society
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• v.7 no.s1
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• pp.30-36
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• 1998

The plasma-spray technique is currently the most frequently used method to produce calcium phosphate coatings. Hydroxyapatite(HAp), one form of calcium phosphate, is preferred by its ability to form a direct bond with living bone, resulting in improvements of implant fixation and faster bone healing. Recently, concerns have been raised regarding the viable use and long-term stability of plasma-spray HAp coatings due to its nature of comparatively thick, porous, and poor bonding strength to metal implants. Thin layers (maximum of few microns) of calcium phosphate were formed by an e-beam evaporation with and without ion bombardments. The Ca/P ration of film was controlled by either using the evaporants having the different ration of Ca/P with addition of CaO, or adjusting the ion beam assist current. The Ca/P ration had great effects on the structure formation after heat treatment and the dissolution bahavior. The calcium phosphate films produced by IBAD exhibited high adhesion strength.

• Proceedings of the Korean Fiber Society Conference
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• 1993.06b
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• pp.36-40
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• 1993

• The korean journal of orthodontics
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• v.37 no.5
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• pp.376-385
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• 2007

Esthetic brackets which resemble the color of natural teeth have been widely used. But the frictional resistance of ceramic brackets, a typical esthetic bracket, is greater than that of metal brackets. The purpose of this study was to measure the frictional resistance of the new calcium phosphate brackets (CPB) which were recently developed and to evaluate its clinical usability by comparing the frictional differences of CPB with metal brackets and metal slot inserted ceramic brackets. Methods: Experimental groups were CPB (Hyaline II, Tomy, Tokyo, Japan), metal bracket (Kosaka, Tomy, Tokyo, Japan) and metal slot inserted ceramic bracket (Clarity, 3M Unitek, Monrovia, CA, USA). All of the brackets had 0.022-inch slot sizes. The brackets were tested with $0.019\;{\times}\;0.025$ inch stainless steel wire (3M Unitek, Monrovia, CA, USA). A biologic model was used to simulate the situation which would occur during orthodontic treatment with fixed appliances. Retraction force was applied at a speed of 5 mm/min for 30 seconds. The frictional resistance was measured on a universal testing machine (Instron 4467, Instron, Norwood, MA, USA). Results: CPB showed significantly higher friction than metal brackets (p < 0.05) and lower friction than metal slot inserted ceramic brackets (p < 0.01). Conclusions: CPB can be considered to be a useful orthodontic esthetic bracket with respect to frictional resistance, as its friction is remarkably lower than that of metal slot inserted ceramic brackets.

• Journal of Soil and Groundwater Environment
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• v.16 no.5
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• pp.31-41
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• 2011

The objectives of this study were to investigate the efficiencies of the stabilizers such as mono-potassium phosphate (MKP), phosphate fertilizer and red mud in treating the mine tailings contaminated with heavy metals and to characterize the changes in fractionations of the heavy metals during the stabilization. The TCLP results showed that the stabilization efficiencies of Cd, Pb and Zn increased with the increase in the stabilizer dosage and the reaction times. MKP showed the highest efficiencies for the heavy metals stabilization among the stabilizers tested. When the mine tailings were amended with MKP, the TCLP concentrations of Cd, Pb and Zn were reduced by 79~97%, 61~84%, and 89~99%, respectively. When the composite stabilizers, MKP/phosphate fertilizer or MKP/red mud, were used, the stabilization efficiencies were lower than when MKP was used as a single stabilizer. The sequential extraction results showed that carbonates fraction of Cd and Zn increased generally. Especially, when red mud was used, carbonates fraction of Cd and Zn increased 5 and 18 times, respectively. In the case of Pb, the treatment with MKP increased residual fraction by 10 times. The results showed that MKP was the most effective in stabilizing the heavy metals (Cd, Pb and Zn) to improve the efficacy of the composite binders.

• Journal of the Korean institute of surface engineering
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• v.28 no.5
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• pp.289-299
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• 1995

The effects of phosphate coating have been studied on physical properties and corrosion resistance of painted aluminum alloy sheet for automobile body. The physical properties (surface roughness, paint adhesion, impact resistance and pencil hardness) and corrosion resistance(cyclic corrosion and filiform corrosion) were investigated. Phosphate coatings enhanced the physical properties of painted Al alloy sheet, especially paint adhesion after the 240hours water immersion test. Phosphate coating also markedly improved the resistance for cyclic corrosion and filiform corrosion of painted cold rolled steel and Zn-Ni plated steel sheet as well as painted Al alloy sheet. The corrosion resistance of painted Al sheets was varied with the concentration of free fluoride ion and metal additives like Ni and Mn in the phosphating bath. A maximum corrosion resistance was obtained at about 300ppm of fluoride ion and additives of Ni and Mn obviously increased the corrosion resistance of painted specimens.

• The Journal of the Korean dental association
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• v.11 no.1
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• pp.41-44
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• 1973

The experiment consisted of cementing full veneer crown of extracted teeth and a standardized cylindrical metal dies (6mm diameter, 6mm height, 1mm shoulder) and then measuring the tensile strength required to remove the cemented restoratoins by the Instron testing machine in the Korea Institude of Science and Technology. The Instron machine was operated at a rate of loading of 0.2cm per minute. From the experiments, the following results obtained. 1. The tension of zinc phosphate and alumina EBA cements were highest all of the cements. 2. The tension of Fynal and the addition of eugenol to zinc Phosphate cements were similar. The addition of eugenol to zinc phosphate cement was half stength and Fynal cement was on third strength than zinc phosphate cement. 3. The tension of zinc oxide-eugenol cement was lowest all of the cements.

• Journal of the Korean GEO-environmental Society
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• v.11 no.11
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• pp.63-75
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• 2010

There are several remediation technologies for heavy metal contaminated soils but increasing cost limits the application of the technology if the contaminated area is large. Therefore, stabilization, which blocks the release of heavy metals or makes slow the release, is one of the applicable technology for the heavy metal contaminated soil. Current study is an applicability test for a smelter area with various stabilizer such as magnetite, hematite, zeolite-A, zeolite-X, zeolite-Y, zinc oxide, calcium oxide, carbon trioxide, manganese oxide, manganese dioxide, fish bone, sodium phosphate. The soil contaminated with arsenic, lead, copper, nickel, and zinc could not be stabilized only one stabilizer which is known to have stability for certain metal. Many of the stabilizer works for a few metal but not all of the heavy metal. In several cases, stabilizers increase the release of the other metals while they stabilize some metals. In general, the stabilizing efficiency was increased with time. For Ni, Pb, calcium oxide, carbon trioxide, manganese oxide had good stabilizing effect in water extractable portion. For Cu, manganese oxide, zeolite showed good results especially in the exchangeable portion of the sequential extraction. For As, magnetite had good ability but most of the metal oxide which showed good result for other heavy metals increased with the release of As. Current study suggest that multiple stabilizers are needed for the contaminated soil and dose of the stabilizer and stabilizing time should be carefully considered for the soil contaminated with various metals.