• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2004.11a
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• pp.80-81
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• 2004

The results obtained are summarized as follows; (1) Boehmite produced in the high temperature and acid region showed a nano fibrous shape with several nm in diameter and several hundreds nm in length having high specific surface areas with a maximum value of $409m^2/g$. (2) In order to obtain nano fibrous boehmite with high surface areas from nano metal powder, the hydrolysis reaction should be done at a high temperature over $50^{\circ}C$, high acidity under pH 6, and terminated before a transition to the bayerite phase.

• Bulletin of the Korean Chemical Society
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• v.33 no.1
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• pp.159-166
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• 2012

We have introduced the Pickering emulsion systems to generate novel confining geometries for the selforganization of monodisperse polymer microspheres using nanoparticle-stabilized emulsion droplets encapsulating the building block particles. Then, through the slow evaporation of emulsion phases by heating, these microspheres were packed into regular polyhedral colloidal clusters covered with nanoparticle-stabilizers made of silica. Furthermore, polymer composite colloidal clusters were burnt out leaving nonspherical hollow micro-particles, in which the configurations of the cluster structure were preserved during calcination. The selfassembled porous architectures in this study will be potentially useful in various applications such as novel building block particles or supporting materials for catalysis or gas adsorption.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.964-965
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• 2006

The injection molded Fe sintered bodies were fabricated using two kinds of nano Fe powders, $Fe-5%vol.ZrO_2$ and $Fe-10vol.%ZrO_2$ powders. The relationship between microstructure and mechanical properties depending on the $ZrO_2$ contents and sintering temperature were characterized by SEM and TEM techniques. In the wear test, the $Fe-0vol%ZrO_2$ sintered bodies showed mainly adhesive wear, but in the Fe-5%vol. $ZrO_2$ and Fe-10vol. % $ZrO_2$ composites the main wear behavior showed abrasive wear mode.

• Journal of Advanced Marine Engineering and Technology
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• v.32 no.4
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• pp.514-521
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• 2008

Many research works for improving a boundary lubrication performance have been executed by using solid lubricants, and been tried to apply an engine lubrication. However those general lubricants have not been applied on engines due to the extreme conditions such as very high temperature and pressure during combustion process in a cylinder. In this study a lubricant containing copper alloy nano-powder is applied on a diesel engine driven by an electric motor. Torques and shaft vibrations are measured, then an engine friction loss and rotating stability are assessed. The results show that the frequency of the vibration is about the same as that of a general lubricant, but the amplitudes in the both X and Y direction are reduced as well as the friction loss is reduced.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.362-363
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• 2006

Nano-structured tungsten carbide compacts with cobalt matrices (WC-Co) offer new opportunities for achieving superior hardness and toughness combinations. A unified modeling and simulation tool has been developed to produce maps of sintering pathways from nanocrystalline WC powder to sintered nano-structured WC-Co compacts. This tool includes (1) die compaction, (2) grain growth, (3) densification, (4) sensitivity analysis, and (5) optimization. All material parameters were obtained by curve fitting based on results with two WC-Co powders. Critical processing parameters are determined based on sensitivity analysis and are optimized to minimize grain size with high density.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.321-322
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• 2006

Nano-structured ceramics, which consist of structural elements with nanometer-size crystallites, are expected to show various unusual properties. We developed the novel nano-structured ceramics which consists of $Si_3N_4$ and TiN and a self-lubricant material. The ceramics was fabricated by powder metallurgy process using mechano-chemical grinding process and short-time sintering process. Each grain size of matrix and the self-lubricant particle was under about 50 nm and a few namometer. It showed high wear resistance and low friction coefficient by controlling of microstructure.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.462-463
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• 2006

Monodispersed and nano-sized Ni powders were synthesized from aqueous nickel sulfate hexahydrate $(NiSO_4{\cdot}6H_2O)$ inside nonionic polymer network by using wet chemical reduction process. The sucrose was used as a nonionic polymer network source. The effect of reaction conditions such as the amount of sucrose and a various reaction temperature, nickel sulfate hexahydrate molarity. The influence of a nonionic polymer network on the particle size of the prepared Ni powders was characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), and particle size analysis (PSA). The results showed that the obtained Ni powders were strong by dependent of the reaction conditions. In particular, the Ni powders prepared inside a nonionic polymer network had smooth spherical shape and narrow particle size distribution.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2001.11a
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• pp.56-56
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• 2001

No Abstract, See Full Text

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2000.11a
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• pp.25-25
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• 2000

• Journal of Powder Materials
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• v.9 no.1
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• pp.1-10
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• 2002