• Korean Journal of Materials Research
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• v.11 no.10
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• pp.869-878
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• 2001

Alumina $(Al_2O_3)$ green bodies were fabricated by gel-casting using three kinds of alumina with different particle size (mean particle size: 4.6 $\mu\textrm{m}$, 0.32 $\mu\textrm{m}$, 10nm). The effects of particle size on gel-casting process and green microstructure were investigated. The optimum dispersion conditions using ammonium salt (D-3019) as dispersant were 0.2 wt% (4.63 $\mu\textrm{m}$), 0.5 wt% (0.32 $\mu\textrm{m}$), and 5.0 wt% (10 nm), in high solid loading. The optimum solid loading of each starting material for gel-casting was obtained as 59 vol% (4.63 $\mu\textrm{m}$), 57 vol% (0.32 $\mu\textrm{m}$), 15 vol% (10 nm), depending on particle size, indicating that nano-size particle (10 nm) represent lower solid loading as high specific surface area than those of other two starting materials. The drying at ambient conditions (humidity; $\thickapprox$90%) was performed more than 48hrs to enable ejection of the part from the mold and then at $120^{\circ}C$ for 2hrs in an air oven, showing no crack and flaw in the dried green bodies. The pore size and distribution of the gelcast green bodies showed the significant decrease with decreasing particle size. Green microstructure was dependent on the pore size and distribution due to the particle size, and on the deairing step. The green density maximum obtained was 58.9% (4.63 $\mu\textrm{m}$), 60% (0.32 $\mu\textrm{m}$), 47% (10 nm) theoretical density (TD), and the deairing step applied before gel-casting did not affect green density.

• Proceedings of the Korea Society of Environmental Toocicology Conference
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• 2002.10a
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• pp.171-171
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• 2002

Recent industrial society has human widely exposed to PAHs that are comming from the incomplete combustion of organic material as widerspread environmetal contaminants. Biological activities of PAHs are not known although PAHs are considered as carcinogens. PAHs in the mammalian cells affect CYP1A1 gene expression as well as other phase II drug metabolizing enzymes as UDPGT, NMOR etc. The mechanism of action of PAHs has been studied extensively, however it is not clear how PAHs turn on CYP1A1 in human breast cancer. Our labolatory have been studied the effect of PAHs in the human breast cancer cell lind MCF7. In this study, we examined the ZR-75-1 human breast cancer cells as a new system to evaluate bioactivity of PAHs. ZR-75-1 human breast cancer cell line has been estabilished from the breast cnacer patient, has estrogen receptors and progesteron receptors. We have been able to estbilish long term culture system of this cells then used for the study to observe the effect of PAHs. We demonstrate that PAHs induced the transcription of an aryl hydrocarbon-responsive reporter vector containing the CYP1A1 promoter and 7-ethoxyresolufin O-deethylase(EROD) activity of CYP1A1 enzyme in a concentration-dependant manner. RT-PCR analysises indicated that PAHs significantly up-regulate the constitutive level of CYP1A1 mRNA. Apparently, ZR-75-1 cells have Aryl hydrocarbon recetors, therefore it would be good experimental tool to study the cross-talk between PAHs and steroid actions.

• Journal of the Korea Fashion and Costume Design Association
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• v.12 no.4
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• pp.15-28
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• 2010

This study was intended to present basic materials for the direction of product planning and marketing strategy to increase the market share of men's underwear. For this purpose, it attempted to classify the groups according to the benefit of pursuing men's underwear and analyze the differences in purchase behavior among the segmented groups. The specific purposes of the study were to investigate the purchase behavior of men's underwear, to segment the consumers into groups according to underwear benefits sought, to investigate the differences in purchase behavior among the groups, and to investigate the differences in demographics among the groups. The questionnaire was distributed to men aged the 20s to the 40s living in Seoul. A total of 297 questionnaires were used for the final analysis. As a result, the following findings were obtained. It was found that 84.8% of the respondents showed there was no favorite underwear brand. They showed the favorite color of translucent color, the favorite style of trunk and brief, the favorite post-processing of silver nano, deo processing, and the favorite material of charcoal. In purchasing men's underwear, the respondents showed a preference for simple image, and the discount store as the place of purchase. The results also showed that there were four groups of underwear benefits sought: sex appeal/individuality, comfort, practicality, and fashion/brand groups. In regard to the group differences, there were significant differences in underwear purchase motives, underwear preferences, store selection criteria, and demographics.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.44 no.3
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• pp.34-40
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• 2012

In this study, new antibacterial materials were developed to manufacture a functional corrugated board. Sulfur solution, a new antibacterial solution made from inorganic sulfur in the laboratory, and other antibacterial mat erials were adopted to treat the surface of a linerboard. We measured the antibacteriocidal and bacteriostatic activities, as well as the fungal resistance of the surface-treated linerboards, to identify the antibacterial properties. The mechanical properties of the surface-treated linerboard were also determined in order to identify the effects of the antibacterial materials on linerboard properties. Linerboard treated with sulfur solution, PVOH, and sodium metasulfite showed the highest antibacterial activity, while linerboard treated with sulfur solution and nano sulfur showed the highest fungal resistance. It was identified that sulfur solution has effective antibacterial properties. The antibacterial materials did not affect the mechanical properties of the surface-treated linerboard, but the binder showed significant effects in terms of the burst strength, the compressive strength, and the stiffness of the linerboard.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.26 no.2
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• pp.172-184
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• 2017

Nanotechnology is a leading branch of technology and is expected to improve national industrial competitiveness. For maintaining a sustainable growth in nanotechnology, Korean government has set up specific plans from a long-term perspective. One of these plans is tracking and promoting certain potential technologies called Future 30 Nanotechnologies. This study aims to develop an analysis framework for comprehending the Future 30 Nanotechnologies. We applied this framework to the carbon nanomaterials field. Through co-authorship and keyword network analysis, we identified the research trends of three countries (i.e., Korea, US, and China.). This research framework could be utilized in the development of a nanotechnology policy.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.4
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• pp.395-403
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• 2012

This is direct bonding many of the metal bumps between FPCB and HPCB substrate. By using an ultrasonic horn mounted on an ultrasonic bonding machine, it is possible to bond gold pads onto the FPCB and HPCB at room temperature without an adhesive like ACA or NCA and high heat and solder. This ultrasonic bonding technology minimizes damage to the material. The process conditions evaluated for obtaining a greater bonding strength than 0.6 kgf, which is commercially required, were 40 kHz of frequency; 0.6MPa of bonding pressure; and 0.5, 1.0, 1.5, and 2.0 s of bonding time. The peel off test was performed for evaluating bonding strength, which was found to be more than 0.80 kgf.

• Applied Chemistry for Engineering
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• v.18 no.4
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• pp.381-385
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• 2007

High density activated carbons electrode materials, for supercapacitor were prepared by chemical KOH activation of cokes as the starting material under Ar atmosphere. By controlling the synthesis conditions and reducing KOH quantity in the activation step, the specific surface area of the product was decreased. BET surface area was measured to be $500{\sim}1260m^2/g$, and the electrode density was in the range of $0.68{\sim}0.83g/cm^3$. Volumetric specific capacitance (unit cell test) was as high as 20 F/cc, which corresponds to gravimetric specific capacitance of about 95 F/cc on the basis of half cell test. It should be noted that the specific capacitance of the activated carbons prepared in this study is superior to that of commercial activated carbons.

• Applied Chemistry for Engineering
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• v.21 no.5
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• pp.564-569
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• 2010

Highly anti-reflective optical property has been focussed in the field of thin film and display because of increasing demands to the high transparency and clearness of optical component. In this study, to obtain anti-reflective property, the formation of aluminium oxide with nanoscaled flowerlike frame structure was introduced as oxide material monolayer on the substrate by hydrothermal synthesis through sol-gel method. The properties of coating layer were measured by the means of UV-Vis spectroscopy, FT-IR spectroscopy, XRD, and FE-SEM. The morphology of coating layer in alumina-sol coated samples was controlled by hydrothermal temperature and time with aid of ultrasound. It was found that high transparency and anti-reflective optical properties were obtained the formation of flowerlike nanoframe structure.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.487-487
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• 2011

Recently graphene has emerged as a fascinating 2D system in condensed-matter physics as well as a new material for the development of nanotechnology. The unusual electronic band structure of graphene allows it to exhibit a strong ambipolar electric field effect with high mobility. These properties lead to the possibility of its application in high-performance transparent conducting films (TCFs). Compared to indium tin oxide (ITO) electrodes, which have a typical sheet resistance of ${\sim}60{\Omega}$/sq and ~85 % transmittance in the visible range (400?900 nm), the CVD-grown graphene electrodes have a higher/flatter transmittance in the visible to IR region and are more robust under bending. Nevertheless, the lowest sheet resistance of the currently available CVD graphene electrodes is higher than that of ITO. Here, we report an ingenious strategy, irradiation of MeV electron beam (e-beam) at room temperature under ambient condition, for obtaining size-homogeneous gold nanoparticle decorated on graphene. The nano-particlization promoted by MeV e-beam irradiation was investigated by transmission electron microscopy, electron energy loss spectroscopy elemental mapping, and energy dispersive X-ray spectroscopy. These results clearly revealed that gold nanoparticle with 10 ~ 15 nm in mean size were decorated along the surface of the graphene after 1.5 MeV-e-beam irradiation. A chemical transformation and charge transfer for the metal gold nanoparticle were systematically explored by X-ray photoelectron spectroscopy and Raman spectroscopy. This approach advances the numerous applications of graphene films as transparent conducting electrodes.

• Korean Chemical Engineering Research
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• v.55 no.1
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• pp.115-120
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• 2017

In recent, it is worldwide issued that nanoscale science and technology as a solution have supported to increase the sensing performance in carbon nanotube based biosensor system. Containing material chemistry in various nanostructures has formed their high potentials for stabilizing and activating biocatalyst as a bioreceptor for medical, food contaminants, and environmental detections using electrode modification technologies. Especially, the large surface area provides the attachment of biocatalysts increasing the biocatalyst loading. Therefore, nano-scale engineering of the biocatalysts have been suggested to be the next stage advancement of biosensors. Here, we would like to study the electrical mechanism depending on the exposure methods (soaking or dropping) to the sample solution to the assembled carbon nanotubes (CNTs) on the gold electrodes of biosensor for a simple and highly sensitive detection. We performed various experiments using polar and non-polar solutions as sampling tests and identified electrical response of assembled CNTs in those solutions.