• Journal of the Korean Ceramic Society
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• v.51 no.5
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• pp.459-465
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• 2014

In this study, Si-SiC composites were fabricated using a Si melt infiltration method using ${\beta}$-SiC/C composite powders synthesized by the carbothermal reduction of $SiO_2-C$ precursors made from a TEOS and a phenol resin. The purity of the synthesized SiC-C composite powders was higher than 99.9993 wt% and the average particle size varied from 4 to $6{\mu}m$ with increasing carbon contents of the $SiO_2-C$ precursors. It was found that the Si-SiC composites fabricated in this study consist of ${\beta}$-SiC and residual Si, without any trace of ${\alpha}$-SiC. The 3-point bending strengths of the fabricated Si-SiC composites were measured and found to be higher than 550 MPa, although the density of the fabricated Si-SiC composite was less than $2.9g/cm^3$. The bending strengths and the densities of the fabricated Si-SiC composites were found to decrease with increasing C/Si mole ratios in the SiC-C composite powders. The specific resistivities of the Si-SiC composites fabricated using the SiC-C composite powders were less than $0.018{\Omega}cm$. With increasing C content in the SiC-C composite powders used for the fabrication of Si-SiC composites, the specific resistivity of the Si-SiC composites was found to slightly increase from 0.0157 to $0.018{\Omega}cm$.

• Journal of the Microelectronics and Packaging Society
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• v.23 no.2
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• pp.1-10
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• 2016

This paper reports the trends of researches and technologies of electronic packaging using graphene. Electronic packaging is to provide the signal and electrical current among electronic components, to remove the heat in electronic systems or components, to protect and support the electronic components from external environment. As the required functions and performances of electronic systems or components increase, the electronic packaging has been intensively attracted attention. Therefore, technologies such as miniaturization, high density, Pb-free material, high reliability, heat dissipation and so on, are required in electronic packaging. Recently, graphene, which is a single two-dimensional layer of carbon atoms, has been extensively investigated because of its superior mechanical, electrical and thermal properties. Until now, many studies have been reported the applications using graphene such as flexible display, electrode, super capacitor, composite materials and so on. In this paper, we will introduce and discuss various studies on recent technologies of electronic packaging using graphene for solving the required issues.

• Journal of the Korean Society of Industry Convergence
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• v.7 no.3
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• pp.259-263
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• 2004

In the manufacture progress of LCD or semiconductor, there are used many kinds of gas like erosion gas, dilution gas, toxic gas as a progress which used these gas there are required high puritize to increase accumulation rate of semiconductor or LCD materials work progress of semiconductor or LCD it demand many things like the material which could minimize metallic dust that could be occured by reaction between gas and transfer pipe laying material, illumination of the surface, emition of the gas, metal liquation, welding etc also demand quality geting stricted. Material-Low-sulfur-contend (0.007-0010), vacuum-arc-remelt(VAR), seamless, high-purity tubing material is recommend for enhance welding lower surface defect density All wetted stainless steel surface must be 316LSS elecrto polishinged with ${\leq}0.254{\mu}m$($10.0{\mu}in$) Ra average surface finish, $Cr/Fe{\geq}1.1$ and $Cr_2O_3$ thickness ${\geq}25{\AA}$ From the AES analytical the oxide layer thickness (23.5~36 angstroms silicon dioxide equivalent) and chromum to iron ratios is similar to those generally found on electropolished stainless steel., molybdenum and silicon contaminants ; elements characteristic of stainless steel (iron, nickel and chromium); and oxygen were found on the surface Phosphorus and nitrogen are common contaminants from the electropolish and passivation steps.

• Journal of Mushroom
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• v.7 no.1
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• pp.27-36
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• 2009

Pleurotus ferulae is an edible mushroom found on a medicinal plant, Ferula assa-foetida, in centeral China. This study was carried out to investigate the cultural characteristics of P. ferulae strains. Characteristics of mycelial growth were investigated for 5 strains of P. ferulae. All the 5 strains showed the best mycelial growth at $25^{\circ}C$ and their growth rate was very low at $35^{\circ}C$. The colony diameter reached to 45~72 mm after 7 days at $25^{\circ}C$. Malt extract agar medium was the best for mycelial growth of the species both in hyphal length and density. Mycelial growth was not affected by various pH from 6.0 to 8.0. An optimal carbon source was arabinose and an optimal nitrogen one was arginine. And an effective substrate for the mycelial growth was 8 to 2 mixture of oak sawdust and cottonseed meal.

• Journal of Mushroom
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• v.9 no.4
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• pp.166-169
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• 2011

In this study we carried out to find suitable nutrient supplement of corncob as a main carbon source for bottle culture of oyster mushroom. Data from chemical analysis of Kapok seed cake(KP) treatment showed 20.2 of C/N ratio, $0.28g/cm^3$ of bulk density and 74.2% of porosity. Mushroom yield of KP treatment is 158g/bottle that is similar to control(150g/bottle). However, the price of KP is 400 won/kg that is cheaper than 550 won/kg of cotton seed cake(CS). The highest REV(relative feed value) also was observed KP treatment. A further study is required determine practical animal performance by feeding the corncob-based KP.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.108-109
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• 2012

This talk will begin with the demonstration of facile synthesis of silicon nanostructures using the magnesiothermic reduction on silica nanostructures prepared via self-assembly, which will be followed by the characterization results of their performance for energy storage. This talk will also report the fabrication and characterization of highly porous, stretchable, and conductive polymer nanocomposites embedded with carbon nanotubes (CNTs) for application in flexible lithium-ion batteries. It will be presented that the porous CNT-embedded PDMS nanocomposites are capable of good electrochemical performance with mechanical flexibility, suggesting these nanocomposites could be outstanding anode candidates for use in flexible lithium-ion batteries. Directed self-assembly (DSA) of block copolymers (BCPs) can generate uniform and periodic patterns within guiding templates, and has been one of the promising nanofabrication methodologies for resolving the resolution limit of optical lithography. BCP self-assembly processing is scalable and of low cost, and is well-suited for integration with existing semiconductor manufacturing techniques. This talk will introduce recent research results (of my research group) on the self-assembly of Si-containing block copolymers for the achievement of sub-10 nm resolution, fast pattern generation, transfer-printing capability onto nonplanar substrates, and device applications for nonvolatile memories. An extraordinarily facile nanofabrication approach that enables sub-10 nm resolutions through the synergic combination of nanotransfer printing (nTP) and DSA of block copolymers is also introduced. This simple printing method can be applied on oxides, metals, polymers, and non-planar substrates without pretreatments. This talk will also report the direct formation of ordered memristor nanostructures on metal and graphene electrodes by the self-assembly of Si-containing BCPs. This approach offers a practical pathway to fabricate high-density resistive memory devices without using high-cost lithography and pattern-transfer processes. Finally, this talk will present a novel approach that can relieve the power consumption issue of phase-change memories by incorporating a thin $SiO_x$ layer formed by BCP self-assembly, which locally blocks the contact between a heater electrode and a phase-change material and reduces the phase-change volume. The writing current decreases by 5 times (corresponding to a power reduction of 1/20) as the occupying area fraction of $SiO_x$ nanostructures varies.

• Korean journal of applied entomology
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• v.47 no.4
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• pp.479-486
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• 2008

The cultural characteristics and antibacterial activities of Cordyceps militaris and Paecilomyces tenuipes were compared. The mycelial growth was the highest on MCM (Mushroom Complete Medium) for C. militaris and on YMA (Yeast Malt Agar) for P. tenuipes. But the mycelial density on MMM (Mushroom Minimal Medium) was lower than other on media. The optimum mycelial growth was observed at $25^{\circ}C$. C. militaris was low mycelial growth when it was transferred over 5 times generation. The carbon source for the optimum mycelial growth was fructose of monosaccharide, maltose of disaccharide and dextrin of polysaccharide. The calcium nitrate of organonitrogen was found the best mycelial growth on C. militaris, while the sodium nitrate observed to be well for mycelial growth on P. tenuipes. The ammonium tartrate was observed to be the best among the inorganonitrogen used for mycelial growth. Antibacterial activities were found out just C. militaris against Bacillus cereus of Gram (+).

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.15 no.1
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• pp.10-15
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• 2005

Effects of CH₄/H₂ flow rate ratio, chuck bias and microwave power on the structural properties and particle densities of diamond thin films deposited on Ti substrates in microwave plasma CVD were examined. High quality diamond thin films were deposited on Ti substrates in 2∼3 CH₄ Vol.% conditions due to the preferential formation of sp³-bonus ana selective removal of sp²-bonus in the CH₄/H₂ mixtures, and the mechanism for the formation of diamond particles on Ti was analysed. Diamond particle density increased with increasing negative chuck bias to Ti substrate due to bias-enhanced nucleation of diamond and the threshold voltage was found at ∼-50 V. With increasing microwave power the evolution from micro-crystalline graphite layer to diamond layer was observed.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.17 no.6
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• pp.277-282
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• 2007

The artificial lightweight aggregate (ALA) was manufactured using coal bottom ashes produced from a thermoelectric power plant with clay and, the sintering temperature and batch composition dependence upon physical properties of ALA were studied. The bottom ash (BA) had 13wt% coarse particle (>4.75mm) and showed very irregular shape so should be crushed to fine particles to be formed with clay by extrusion process. Also the bottom ash contained a many unburned carbon which generates the gas by oxidation and lighten a aggregate during a sintering process. Plastic index of green bodies decreased with increasing bottom ash content but the extrusion forming process was possible for the green body containing BA up to 40wt% whose plastic index and plastic limit were around 10 and 22 respectively. The ALA containing $30{\sim}40wt%$ BA sintered at $1100{\sim}1200^{\circ}C$ showed a volume specific density of $1.3{\sim}1.5$ and water absorption of $13{\sim}15%$ and could be appled for high-rise building and super-long bridge.

• Korean Chemical Engineering Research
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• v.54 no.5
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• pp.693-697
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• 2016

In this study, we fabricated the catalysts for enzymatic biofuel cell anode with carbon nanotube (CNT), glucose oxidase (GOx) and various molecular weights branched poly(ethyleneimine)(bPEI) and terephthalaldehyde (TPA) as cross-linker. In case of GOx/bPEI/CNT using only physical entrapments for immobilization, the molecular weights of bPEI didn't affect to electrochemical performances and long term stability. but that of the catalysts cross linked via TPA (TPA[GOx/bPEI/CNT]) improved and the mass transfer of glucose to FAD was interrupted as increasing of the bPEI's molecular weights. Furthermore, it was confirmed that the optimum molecular weight of PEI for TPA [GOx/bPEI/CNT]) structure is 750k that showed marvelous high performance (maximum power density of $0.995mW{\cdot}cm^{-2}$).