• Journal of Korean Foot and Ankle Society
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• v.17 no.4
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• pp.277-282
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• 2013

Purpose: This study was performed to evaluate the effectiveness of self-home dressing with nanocrystalline silver dressing method on the treatment of chronic ulcer wounds of the foot. Material and Methods: One hundred-nine patients with chronic foot ulcer due to various causes were treated with nanocrystalline silver dressing material. Dressing was done by themselves in their home. Dressing changes were performed every 2 to 3 days until complete reepithelization. Results: One hundred two cases of all cases had a complete reepithelization. It took 49 days to have a complete reepithelization on average. Seven cases failed to complete reepithelization because of infection. There was no silver intoxication in any cases. Conclusion: Using nanocrystalline silver is a useful dressing method for various superficial chronic ulcer and it can be done by themselves at their home. Thus it is considered to be more comfortable to both patients and doctors.

• Applied Microscopy
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• v.47 no.1
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• pp.29-35
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• 2017

Transverse magnetic field annealing (TFA) was carried out on $Fe_{73.5}Cu_1Nb_3Si_{15.5}B_7$ nano-crystalline magnetic core with the aim at decreasing coercivity ($H_c$) while keeping high inductance ($L_s$). The magnetic field generated by direct current (DC) was applied on the magnetic core during different selected annealing stages and it was proved that the nanocrystalline magnetic core achieved lowest $H_c$ when applying transverse field during the whole annealing process (TFA1). Although the microstructure and crystallization degree of the nanocrystalline magnetic core exhibited no obvious difference after TFA1 compared to no field annealing, the TFA1 sample showed a more uniform nanostructure with a smaller mean square deviation of grain size distribution. $H_c$ of the nanocrystalline magnetic core annealed under TFA1 decreased along with the increasing magnetic field. As a result, the certain size nanocrystalline magnetic core with low $H_c$ of 0.6 A/m, low core loss (W at 20 kHz) of 1.6 W/kg under flux density of 0.2 T and high $L_s$ of $13.8{\mu}H$ were obtained after TFA1 with the DC intensity of 140 A. The combination of high $L_s$ with excellent magnetic properties promised this nanocrystalline alloy an outstanding economical application in high frequency transformers.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 1998.10b
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• pp.40-40
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• 1998

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 1998.05a
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• pp.57-57
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• 1998

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 1996.04a
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• pp.15-15
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• 1996

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1997.03a
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• pp.73-76
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• 1997

Nanocrystalline materials have been modeled as a mixture of the crystallite and the grain boundary phases. The mechanical property has been calculated using the rule of mixtures based on the volume fractions. The critical grain size concept suggested by Nieh and Wadsworth and porous material model suggested by Lee and Kim were applied to the calculation. The theoretical results fit very well with the experimental values

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.10a
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• pp.136-138
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• 2005

The responses of nanocrystalline aluminum powder of different grain sizes, was modeled Using, Khan, Huang, and Liang (KHL) viscoplastic model including hi-linear Hall-Petch type, based on experimental measurements. Correlation of strain-rate-dependent stress responses for different grain sizes were in good agreement with the experimental results.

• Journal of Powder Materials
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• v.3 no.4
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• pp.233-245
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• 1996

Nanocrystalline materials, with a grain size of typically <100 nm, are a new class of materials with properties vastly different from and often superior to those of the conventional coarse-grained materials. These materials can be synthesized by a number of different techniques and the grain size, morphology, and composition can be controlled by controlling the process parameters. In comparison to the coarse-grained materials, nanocrystalline materials show higher strength and hardness, enhanced diffusivity, improved ductility/toughness, reduced, density, reduced elastic modulus, higher electrical resistivity, increased specific heat, higher coefficient of thermal expansion, lower thermal conductivity, and superior soft and hard magnetic properties. Limited quantities of these materials are presently produced and marketed in the US, Canada, and elsewhere. Applications for these materials are being actively explored. The present article discusses the synthesis, structure, thermal stability, properties, and potential application of nanocrystalline materials.

• Journal of Powder Materials
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• v.6 no.4
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• pp.277-285
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• 1999

Mechanical properties of nanocrystalline Al-5at.%Ti alloy were investigated through high temperature compression test. Al-5at.%Ti nanocrystalline metal powders, which had finer and more equiaxed shape than those produced at room temperature, were produced by mechanical alloying at low temperature. The powders were successfully consolidated to 99fo of theoretical density by vacuum hot pressing. XRD and TEM analysis revealed that $Al_3Ti$ intermetallic compounds formed inside powders and pure Al region with coarse grains formed between powders, especially at triple junction. Mechanical properties in terms of hardness and strength were improved by grain size refinement, but ductility decreased presumably due to the formation of the weak interfaces between Al pool and powders.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.588-590
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• 2008

Yellow-emitting $Y_3Al_5O_{12}$:Ce nanocrystalline phosphor and orange-emitting CdS:Mn/ZnS core/shell quantum dots were prepared by a modified polyol and a reverse micelle chemistry, respectively. To compensate a poor color rendering index of YAG:Ce nanocrystalline phosphor due to the lack of red spectral component, CdS:Mn/ZnS quantum dots were blended into YAG:Ce. Based on spectral evolutions in the blended systems, hybrid white light emitting diodes are fabricated and characterized.