• Proceedings of the Korean Fiber Society Conference
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• 2002.04a
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• pp.321-324
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• 2002

Recently, organic-inorganic nanocomposites have attracted great interest from researchers since they frequently exhibit unexpected hybrid properties synergistically derived from two components[1]. The addition of highly dispersed inorganic nano-sized fillers permits improvement of certain properties of polymers as compared with conventional particulate composites; increase of modulus and strength, improved barrier properties, increase in solvent and heat resistance, and good optical properties[2]. (omitted)

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2006.04a
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• pp.55-55
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• 2006

• Proceedings of the Korean Society For Composite Materials Conference
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• 2003.10a
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• pp.103-106
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• 2003

In this work the novel potential epoxy resins, were synthesized and acrylated. Their structures were confirmed by means of FTIR, $^1H NMR, and^{13}/C NMR$ spectroscopies. Also, we were to note the effect of W curing on functional group changes of VE/UP blend system after UV curing.

• Proceedings of the Korean Vacuum Society Conference
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• 2003.08a
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• pp.178-178
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• 2003

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.11
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• pp.4929-4934
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• 2016

Cancer, a worldwide epidemic disease with diverse origins, involves abnormal cell growth with the potential to invade other parts of the body. Globally, it is the main cause of mortality and morbidity. To overcome the drawbacks of the commercially available chemotherapies, natural products-loaded nano-composites are recommended to improve cancer targetability and decrease the harmful impact on normal cells. This study aimed at exploring the anti-cancer impacts of Moringa oleifera seed oil in its free- (MO) and nano-formulations (MOn) through studying whether it mechanistically promotes mitochondrial apoptosis-mediating cell death. Mitochondrial-based cytotoxicity and flow cytometric-based apoptosis analyses were performed on cancer HepG2, MCF7, HCT 116, and Caco-2 cell lines against normal kidney BHK-21 cell line. The present study resulted that MOn triggered colorectal cancer Caco-2 and HCT 116 cytotoxicity via mitochondrial dysfunction more powerful than its free counterpart (MO). On the other side, MOn and MO remarkably induces HCT 116 mitochondrial apoptosis, while sparing normal BHK-21 cells with minimal cytotoxic effect. The present results concluded that nano-micelle of Moringa oleifera seed oil (MOn) can provide a novel therapeutic approach for colorectal and breast cancers via mitochondrial-mediated apoptosis, while sparing normal and even liver cancer cells a bit healthy or with minimal harmful effect. Intriguingly, MOn induced breast cancer not hepatocellular carcinoma cell death.

• Korean Journal of Materials Research
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• v.20 no.7
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• pp.392-400
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• 2010

The electrospinning process was established as a promising method to fabricate nano and micro-textured scaffolds for tissue engineering applications. A BCP-loaded PCL micro-textured scaffold thus can be a viable option. The biocompatibility as well as the mechanical properties of such scaffold materials should be optimized for this purpose. In this study, a composite scaffold of poly ($\varepsilon$-caprolactone) (PCL)-biphase calcium phosphate (BCP) was successfully fabricated by electrospinning. EDS and XRD data show successful loading of BCP nano particles in the PCL fibers. Morphological characterization of fibers shows that with a higher loaded BCP content the fiber surface was rougher and the diameter was approximately 1 to 7 ${\mu}m$. Tensile modulus and ultimate tensile stress reached their highest values in the PCL- 10 wt% BCP composite. When content of nano ceramic particles was low, they were dispersed in the fibers as reinforcements for the polymer matrix. However, at a high content of ceramic particles, the particles tend to agglomerate and lead to decreasing tensile modulus and ultimate stress of the PCL-BCP composite mats. Therefore, the use of nano BCP content for distribution in fiber polymer using BCP for reinforcement is limited. Tensile strain decreased with increasing content of BCP loading. From in vitro study using MG-63 osteoblast cells and L-929 fibroblast like cells, it was confirmed that electrospun PCL-BCP composite mats were biocompatible and that spreading behavior was good. As BCP content increased, the area of cell spreading on the surface of the mats also increased. Cells showed the best adherence on the surface of composite mats at 50 wt% BCP for both L-929 fibroblast-like cells and MG-63 osteoblast cell. PCL- BCP composites are a promising material for application in bone scaffolds.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.3
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• pp.187-192
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• 2017

This paper presents an ongoing study to develop a novel pressure sensor by means of a Nano Carbon Piezoresistive Composite (NCPC). The sensor was fabricated using the 3D printing process. We designed a miniaturized cantilever-type sensor electrode to improve the pressure sensing performance and utilized a 3D printer to build a small-sized body. The sensor electrode was made of 2 wt％ MWCNT/epoxy piezoresistive nano-composite, and the sensor body was encapsulated with a pipe plug cap for easy installation to any pressure system. The piezoresistivity responses of the sensor were converted into stable voltage outputs by using a signal processing system, which is similar to a conventional foil strain gauge. We evaluated the pressure-sensing performances using a pressure calibrator in the lab environment. The 3D-printed cantilever electrode pressure sensor showed linear voltage outputs of up to 16,500 KPa, which is a 200％ improvement in the pressure sensing range when compared with the bulk-type electrode used in our previous work.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 1996.11a
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• pp.6-6
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• 1996

Ceramic based nanocomposite, in which nano-sized ceramics and metals were dispersed within matrix grains and/or at grain boundaries, were successfully fabricated in the ceramic/cerarnic and ceramic/metal composite systems such as $Al_2O_3$/SiC, $Al_2O_3$/$Si_3N_4$, MgO/SiC, mullite/SiC, $Si_3N_4/SiC, $Si_3N_4$/B, $Al_2O_3$/W, $Al_2O_3$/Mo, $Al_2O_3$/Ni and $ZrO_2$/Mo systems. In these systems, the ceramiclceramic composites were fabricated from homogeneously mixed powders, powders with thin coatings of the second phases and amorphous precursor composite powders by usual powder metallurgical methods. The ceramiclmetal nanocomposites were prepared by combination of H2 reduction of metal oxides in the early stage of sinterings and usual powder metallurgical processes. The transmission electron microscopic observation for the $Al_2O_3$/SiC nanocomposite indicated that the second phases less than 70nm were mainly located within matrix grains and the larger particles were dispersed at the grain boundaries. The similar observation was also identified for other cerarnic/ceramic and ceramiclmetal nanocornposites. The striking findings in these nanocomposites were that mechanical properties were significantly improved by the nano-sized dispersion from 5 to 10 vol% even at high temperatures. For example, the improvement in hcture strength by 2 to 5 times and in creep resistance by 2 to 4 orders was observed not only for the ceramidceramic nanocomposites but also for the ceramiclmetal nanocomposites with only 5~01%se cond phase. The newly developed silicon nitride/boron nitride nanocomposites, in which nano-sized hexagonal BN particulates with low Young's modulus and fracture strength were dispersed mainly within matrix grains, gave also the strong improvement in fracture strength and thermal shock fracture resistance. In presentation, the process-rnicro/nanostructure-properties relationship will be presented in detail. The special emphasis will be placed on the understanding of the roles of nano-sized dispersions on mechanical properties.

• Journal of the Korean Magnetics Society
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• v.22 no.1
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• pp.11-14
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• 2012

The composites of expanded graphite oxide and magnetic nanoparticle (Ni and Co) were synthesized by using simple chemical method. From the raw material natural graphite, the expanded graphite was fabricated using sulfuric acid and $1^{st}$ heat treatment at $600^{\circ}C$ for 1 hour. The expanded graphite was changed to expanded graphite oxide by 2nd heat treatment at $1050^{\circ}C$ for 15 sec and chemical oxidation. The expanded graphite oxide/1-methyl-2-pyrrolidone solution reacts with the magnetic nanoparticle to form a magnetic graphite oxide composite. These graphite-based materials were characterized by x-ray diffractometer, Raman spectroscopy, transmission electron microscope, and vibration sample magnetometer. We expect that these results of this paper were become basis research of graphite oxide composite.

• Elastomers and Composites
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• v.51 no.4
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• pp.342-349
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• 2016

Characteristics of the swelling-induced wrinkles on the surfaces of natural rubber (NR) film were investigated. The wrinkle structure was generated by swelling of NR film pre-stretched and firmly bonded onto an aluminum substrate in hexane. A novel experimental method was adopted to replicate the swelling-induced wrinkles on the NR film using an epoxy-hardener system. To get insight into the wrinkle parameters; the wrinkle length (L), wrinkle distance (D), wrinkle height (H) and the angle between two consecutive wrinkles (${\theta}$), the cross-sections of the replicas obtained from saturated swollen NR film were examined using an optical microscopy (OM). From the OM images, the wrinkling parameters were measured as a function of the thickness of NR film from 0.42 to 1.76 mm. Also, it was evaluated that the effects of swelling time on the wrinkling parameters. The length (L), distance (D) and height (H) of wrinkles increased as the thickness of the NR film and the swelling time increased. However, the angle between the wrinkles (${\theta}$) showed a sharp decrease up to a swelling time of 200 minutes and slightly decreased afterwards.