• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2005.11a
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• pp.92-93
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• 2005

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2002.11a
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• pp.34-35
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• 2002

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2004.11a
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• pp.25-25
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• 2004

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2003.04a
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• pp.51-51
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• 2003

• The Journal of Korean Academy of Prosthodontics
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• v.22 no.1
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• pp.33-50
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• 1984

The purpose of this study was to investigate whether the ashed tooth powder is utilized as an alternative material of the implant to recovery the bony defect. For this purpose its biocompatibility was evaluated comparing to the synthetic calcium phosphate compounds, such as Syntograft and Calcitite, as well as the vacuum firing porcelain (Ceramco Inc.) which is anticipated to use as a matrix to aid sintering. Bony defects to exposure the bone marrow, $3{\times}5$ mm in size, were created in the right and left tibias of fifteen rabbits, and then the ashed tooth powder at $950^{\circ}C$, the porcelain powder, Syhtograft and Calcitite were inserted in the defects of twelve rabbits of the experimental group and the blood clot only was filled in the defects of three rabbits of the control group. The experimental and control rabbits were sacrificed at 1st, 2nd 3rd week after implantation and the histologic examination was performed. The ashed tooth powder in order to make the needed form of the implant was molded using the cylindrical mold 1 cm high, 1 cm in diameter under the pressure of $1000kg/cm^2$ and the ashed tooth powder was sintered at $1100^{\circ}C$ for 1 hour and the mixture of the porcelain powder and the ashed tooth powder at the weight ratio of 7:3, 6:4, 5:5, 4:6 were molded in the same manner and were sintered at $925^{\circ}C$. From this sintered material, square shaped implants were prepared in the dimension of $2{\times}4{\times}6mm$. The prepared implants were surgically placed in the subperiosteum of lateral surfaces of the right and left mandibular bodies. The dogs were sacrificed at 4 weeks, and then the specimens were examined using the light and scanning electron microscopes. The results of this study were obtained as follows: 1. Any inflammatory response was not noted after implanting of the ashed tooth powder, Syntograft, Calcitite and the porcelain powder during the whole experimental period after implantation. 2. Induction of the new bone formation was significantly shown in the ashed tooth powder, Syntograft and Calcitite. 3. The more the porcelain powder was contained in the implants, the more the porosity was and the bigger the pore size was under the scanning electron microscope. And there was ingrowing of the fibrous connective and the osteoid tissue. 4. The osteoid tissues were found to be directly fused to the implant of the ashed tooth powder, and the mixture implant of the porcelain powder and the ashed tooth powder at the weight ratio of 4:6 under the light and scanning electron microscopes.

• Journal of the Korean Ceramic Society
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• v.55 no.4
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• pp.352-357
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• 2018

The slip casting process is widely used to make green bodies from ceramic slips into dense compacts with homogeneous microstructure. However, stress may be generated inside the green body during drying, and can lead to cracking and bending during sintering. When starting from the spherical powders with mono-size distribution to make the close packed body, interstitial voids on octahedral and tetrahedral sites are formed. In this research, experiments were carried out with powders of three size types (host powder (H), octahedral void filling powder (O) and tetrahedral void filling powder (T)) controlled for average particle size by milling from two commercial alumina powders. Slips were prepared using three different powder batches from H only, H+O or H+O+T mixed powders. After manufacturing green compacts by solid-casting, compacts were dried at constant temperature and humidity and sintered at $1650^{\circ}C$. Alumina samples fabricated from the multi-sized powder mixture had improved compacted and sintered densities.

• Journal of Powder Materials
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• v.10 no.4
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• pp.270-274
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• 2003

Recently, the fabrication process of W-Cu nanocomposite powders has been researched to improve the sinterability by mechanochemical process (MCP), which consists of ball milling and hydrogen-reduction with W- and Cu-oxide mixture. However, there are many control variables in this process because the W oxides are hydrogen-reduced via several reduction stages at high temperature over 80$0^{\circ}C$ with susceptive reduction conditions. In this experiment, the W-15 wt%Cu nanocomposite powder was fabricated with the ball-milling and hydrogen-reduction process using W and CuO powder. The microstructure of the fabricated W-Cu nanocomposite powder was homogeneously composed of the fine W particles embedded in the Cu matrix. In the sintering process, the solid state sintering was certainly observed around 85$0^{\circ}C$ at the heating rate of 1$0^{\circ}C$/min. It is considered that the solid state sintering at low temperature range should occur as a result of the sintering of Cu phase between aggregates. The specimen was fully densified over 98% for theoretical density at 120$0^{\circ}C$ for 1 h with the heating rate of 1$0^{\circ}C$/min.

• Journal of the Korean Geotechnical Society
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• v.26 no.4
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• pp.5-14
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• 2010

Three years of frost heave field experiments were conducted to evaluate a method for reducing heave using a recycled tire powder-soil mixture. By mixing Tomakomai soil with 20% recycled tire powder, frost heave amount was drastically decreased. The results of the field experiment confirm that recycled tire powder is an excellent material for use in controlling the total amount of heave. The restraining effect of a recycled tire powder-soil mixture is qualitatively analyzed based on amount of frost heave, frost heave ratio, thermal conductivity, permeability and segregation potential theory.

• Biotechnology and Bioprocess Engineering:BBE
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• v.9 no.5
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• pp.369-373
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• 2004

In order to elucidate the possibility of artificial production of p. ferulae by solid-state culture, the optimization of culture conditions was carried out. When $NH_4H_2PO_4$ and $CaCO_3$ were used in the cultures using test tube with 30 g of Populus sawdust at $25^{\circ}C{\pm}1$ in the dark, the favored mycelial growth was observed with $1\%$ of $NH_4H_2PO_4$ and the production of polysaccharide was 7.85 mg/100 mg of mycelium with $1\%$ of $CaCO_3$. The mixtures of $80\%$ of Populus Sawdust and $20\%$ of rice bran at $60\%$ of water content were determined to be optimal for the production of fruiting bodies in the sawdust culture. When three treatments containing various ratios of garlic powder were conducted, yields of fruiting bodies were drasti[ally higher than those of Synthetic mixture without garlic powder The highest yield (143 g/bag) was obtained with $7\%$ garlic powder. The yield of synthetic mixture containing $7\%$ of garlic powder was $83\%$ higher than that of Sawdust culture. The reason why garlic powder did support growth was not clear but it is possible that garlic powder might contain effective components for the formation of fruiting body. The optimal synthetic mixture composition consisted of cotton seed $77\%$, lime $6.4\%,\;K_2HPO_4\;0.2\%,\;KH_2PO_4\;0.2\%,\;CaHPO_4\;0.2\%$, corn flour $4\%$, wheat flour $5\%$, and garlic pow-der $7\%$.

• Composites Research
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• v.34 no.5
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• pp.330-336
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• 2021

Alumina powder is one of the widely used materials for industry, but there is a problem that the strength of the product changes depending on the powder packing state. To solve the above problem, previous studies have been conducted to increase the particle packing efficiency, but most of the existing studies analyzed the packing characteristics of millimeter-scale particles, so the physical properties are different from those of the micrometer scale. It is difficult to apply to the micrometer scale. In this paper, a three-step experiment was performed using a statistical method to increase packing using micrometer-scale alumina powder. First, a size combination with high packing and a mixing ratio were selected using the mixture test design method, and an appropriate excitation frequency was selected by analyzing the height change according to the frequency change in the vibration test apparatus. Finally, an alumina powder packing experiment was performed based on the experimental results mentioned above. As a result, it was confirmed that the maximum height variation was 42% higher than the maximum value of the 155 measurements performed when selecting the packing size combination. It is thought that this study will serve as basic data for processing and packing research using fine powder.