• Advances in nano research
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• v.5 no.1
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• pp.35-47
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• 2017

This paper deals with free vibration analysis of nanosize rings and arches with consideration of surface effects. The Gurtin-Murdach model is employed for incorporating the surface effect parameters including surface density, while the small scale effect is taken into consideration based on nonlocal elasticity theory of Eringen. An analytical Navier solution is presented to solve the governing equations of motions. Comparison between results of the present work and those available in the literature shows the accuracy of this method. It is explicitly shown that the vibration characteristics of the curved nanosize beams are significantly influenced by the surface density effects. Moreover, it is shown that by increasing the nonlocal parameter, the influence of surface density reduce to zero, and the natural frequency reaches its classical value. Numerical results are presented to serve as benchmarks for future analyses of nanosize rings and arches.

• Advances in nano research
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• v.3 no.1
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• pp.49-54
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• 2015

The structure represents symmetrical metal electrode (gate 1) - front $SiO_2$ layer - n-Si nanowire FET - buried $SiO_2$ layer - metal electrode (gate 2). At the symmetrical gate voltages high conductive regions near the gate 1 - front $SiO_2$ and gate 2 - buried $SiO_2$ interfaces correspondingly, and low conductive region in the central region of the NW are formed. Possibilities of applications of nanosize FETs at the deep inversion and depletion as a distributed capacitance are demonstrated. Capacity density is an order to ${\sim}{\mu}F/cm^2$. The charge density, it distribution and capacity value in the nanowire can be controlled by a small changes in the gate voltages. at the non-symmetrical gate voltages high conductive regions will move to corresponding interfaces and low conductive region will modulate non-symmetrically. In this case source-drain current of the FET will redistributed and change current way. This gives opportunity to investigate surface and bulk transport processes in the nanosize inversion channel.

• Bulletin of the Korean Chemical Society
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• v.28 no.11
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• pp.1902-1909
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• 2007

This account reports an overview of our findings in homogeneous Pd-catalyzed reactions. Herein we describe the new design in reactions of Group 14 element compounds and in homogeneous nanosize Pd catalysts. In the early stages of our study, we developed Pd-catalyzed transformations of allylic esters with disilanes, silylcyanides and acylsilanes to the corresponding silylation, cyanation and acylation products, respectively. We also developed a Pd-catalyzed three component coupling reaction of Group 14 element compounds involving 1,3-diene and acid chlorides to form β,γ-unsaturated ketone as a single product. Recently, we focus our attention on modifying the catalytic environment by nanosize Pd in order to improve the performance of Pd catalysts. These nanosystems realize efficient catalytic environment with remarkable enhancement in catalytic activity and unprecedented selectivity.

• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.727-730
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• 2001

Electrical wire explosion (EWE) is characterized by great current density and rapid metal heating, which make itself an ideal tool for nano-materials manufacturing technology. The EWE requires a high voltage electric-energy source. In the current experimental set-up a high voltage capacitor is used for the purpose. Hence, a power supply that is capable of charging the capacitor to a target voltage is required. One of the special requirements is the precise controllability of the stored energy level in the capacitor. Through this study a high voltage capacitor charger using a series resonant converter technology has been developed for the production of nanosize powder. A load capacitor of $32{\mu}F$ can be charged up to 20kV by the developed capacitor charger and discharged through a gap switch and a copper wire.

• Journal of the Korean Ceramic Society
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• v.37 no.12
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• pp.1146-1149
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• 2000

표면윤활층 처리와 540 MPa 까지의 진공가압성형을 통하여 나노 TiO$_2$과립 분말의 가압성형공정에서 나타나는 접합압력을 확인하였으며, 접합압력 상하에서 제조된 시편의 소결특성을 $700^{\circ}C$ 등온 소결을 통하여 분석하였다. 접합압력 이상에서 가압성형한 성형체를 $700^{\circ}C$에서 48시간 소결하여 96%의 높은 소결밀도와 112 nm의 평균 결정립 크기를 얻었다.

• Korean Journal of Materials Research
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• v.22 no.12
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• pp.643-649
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• 2012

Coatings composited with alumina and Perfluoro alkoxyalkane (PFA) resin were deposited on stainless steel plate (SUS304) to further improve corrosion resistance. Plate (ca. $10{\mu}m$) and/or nanosize (27~43 nm) alumina used as inorganic additives were mixed in PFA resin to make alumina-fluoro composite coatings. These coatings were deposited on SUS304 plate with wet spray coating and then the film was cured thermally. According to the amount and ratio of the two kinds of alumina having plate morphology and nano size, corrosion resistance of the film was evaluated under strong acids (HF, HCl) and a strong base (NaOH). The film prepared with the addition of 5~10 wt% alumina powders in PFA resin showed corrosion resistance superior to that of pure PFA resin film. However, for the film prepared with alumina content above 10 wt%, the corrosion resistance did not improve with the physical properties, such as surface hardness and adhesion. The film prepared with plate/nanosize (weight ratio = 1/2) alumina especially enhanced the surface hardness and corrosion resistance. This can be explained as showing that the plate and the nanosize alumina dispersed in PFA resin effectively suppressed the penetration of cations and anions due to the long penetration length and fewer defects that accompany the improved surface hardness under a serious environment of 10% HF solution for over 120 hrs.

• Journal of the Korean Ceramic Society
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• v.46 no.6
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• pp.592-595
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• 2009

Nanosize NiO powder was prepared by mixing acidic nickel nitrate with basic nickel carbonate. The particle size and morphology of NiO were mainly governed by the mole ratio of the nitrate to the carbonate. The effects were studied by DSC, XRD, FTIR, and SEM. Heat treatment conditions influence the particle size distribution of produced NiO powder extensively for the case of 3N7C (3 moles of the nitrate and 7 moles of the carbonate) and 4N6C, but only slightly for 1N9C and 2N8C. Uniform pseudospherical NiO particles were obtained in $50{\sim}70$ nm for 1N9C and $30{\sim}60$ nm for 2N8C by calcination at $750{^{\circ}C}$ for 2 h.

• Proceedings of the Korean Vacuum Society Conference
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• 2009.02a
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• pp.123.2-123.2
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• 2009

• Ceramist
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• v.12 no.3
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• pp.30-34
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• 2009

• Proceedings of the Korean Vacuum Society Conference
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• 2002.02a
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• pp.106-106
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• 2002