• Journal of the Korea Institute of Military Science and Technology
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• v.13 no.4
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• pp.699-707
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• 2010

Electric-field-induced electron emission from the three kinds of $Pb(Zr_{0.56}Ti_{0.44})O_3$ ferroelectric cathodes with different electrode structure has been investigated. Regardless of the electrode structures, a threshold field of the each cathode was 2.5-2.6kV/mm, which is 3 times higher than the coercive field of $Pb(Zr_{0.56}Ti_{0.44})O_3$ material. Although the waveform of the electron currents was affected by the structure of the electrode, no significant difference for the emission properties such as the peak current and the pulse width was observed from the three kinds of the cathodes. However, the current density of the cathode was dependent on the electrode structure. From the simulation of electric field distribution, the surface flashover, and the injury region of the cathode surface, it was proved that the prime electrons were initiated at the electrode-ceramic-vacuum triple point by field emission and the emission currents were strongly enhanced by the surface plasma.

• Nano
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• v.13 no.12
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• pp.1850149.1-1850149.10
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• 2018

Ferroelectric particles have been applied in the photocatalytic field because the spontaneous polarization results in the internal electric field, which can accelerate the separation and migration of photogenerated carriers. In this study, the $BaTiO_3$ (BT) fibers are synthesized by electrospinning. The BT fibers calcined above $800^{\circ}C$ exhibit a strong ferroelectric property, which is verified by a typical butterfly-shaped displacement-voltage loop. It is found that the BT fibers with the single-domain structure exhibit better photocatalytic performance than that with the multi-domain configuration. When the single-domain transforms into multi-domain, the integrated internal electric field correspondingly breaks up, inducing that the internal electric field might cancel each other out and diminish the separation of photogenerated carriers. Also, the Au nanoparticles can improve the photocatalytic activity further on account of the surface plasmon resonance. Therefore, it is suggested that Au nanoparticles decorated on ferroelectric BT nanomaterials are promising photocatalysts.

• ETRI Journal
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• v.25 no.3
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• pp.203-209
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• 2003

This paper reports on our investigation of DC and RF characteristics of p-channel metal oxide semiconductor field effect transistors (pMOSFETs) with a compressively strained $Si_{0.8}Ge_{0.2}$ channel. Because of enhanced hole mobility in the $Si_{0.8}Ge_{0.2}$ buried layer, the $Si_{0.8}Ge_{0.2}$ pMOSFET showed improved DC and RF characteristics. We demonstrate that the 1/f noise in the $Si_{0.8}Ge_{0.2}$ pMOSFET was much lower than that in the all-Si counterpart, regardless of gate-oxide degradation by electrical stress. These results suggest that the $Si_{0.8}Ge_{0.2}$ pMOSFET is suitable for RF applications that require high speed and low 1/f noise.

• Transactions on Electrical and Electronic Materials
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• v.13 no.2
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• pp.69-72
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• 2012

In this study, deposition of low-dielectric constant SiOC(H) films by conventional plasma-enhanced chemical vapor deposition (PECVD) were investigated through various characterization techniques. The results show that, with an increase in the plasma power density, the relative dielectric constant (k) of the deposited films decreases whereas the refractive index increases. This is mainly due to the incorporation of organic molecules with $CH_3$ group into the Si-O-Si cage structure. It is as confirmed by FT-IR measurements in which the absorption peak at 1,129 $cm^{-1}$ corresponding to Si-O-Si cage structure increases with power plasma density. Electrical characterization reveals that even after fast thermal annealing process, the leakage current density of the deposited films is in the order of $10^{-11}$ A/cm at 1.5 MV/cm. The reliability of the SiOC(H) film is also further characterized by using BTS test.

• Journal of the Optical Society of Korea
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• v.14 no.2
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• pp.65-76
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• 2010

Plasmonic-based biosensing technologies have been successfully commercialized and applied for monitoring various biomolecular interactions occurring at a sensor surface. In particular, the recent advances in nanofabrication methods and nanoparticle syntheses provide a new route to overcome the limitations of a conventional surface plasmon resonance biosensor, such as detection limit, sensitivity, selectivity, and throughput. In this paper, optical and physical properties of plasmonic nanostructures and their contributions to a realization of enhanced optical detection platforms are reviewed. Following vast surveys of the exploitation of metallic nanostructures supporting localized field enhancement, we will propose an outlook for future directions associated with a development of new types of plasmonic sensing substrates

• Proceedings of the KIEE Conference
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• 2008.11a
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• pp.122-124
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• 2008

Korea Electric Power Research Institute has being carried out an IEC 61580 communication service test on IED trial products developed related to power IT project "The verification of Performance of the Substation Automation System and Its Field Test". This paper describes control testing, one of the IEC 61850 conformance testing items, which consists of DO, enhanced DO, SBO and enhanced SBO with a number of test cases.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.600-600
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• 2013

We have fabricated Cr nanodot Schottky diodes utilizing AAO templates formed on n-Si substrates. Three different sizes of Cr nanodots (about 75.0, 57.6, and 35.8 nm) were obtained by controlling the height of the AAO template. Cr nanodot Schottky diodes showed a rectifying behavior with low SBHs of 0.17~0.20 eV and high ideality factors of 5.6~9.2 compared to those for the bulk diode. Also, Cr nanodot Schottky diodes with smaller diameters yield higher current densities than those with larger diameters. These electrical behaviors can be explained by both Schottky barrier height (SBH) lowering effects and enhanced tunneling current due to the nanoscale size of the Schottky contact. Also, we have fabricated Cr-Si nanorod Schottky diodes with three different lengths (130, 220, and 330 nm) by dry etching of n-Si substrate. Cr-Si nanorod Schottky diodes with longer nanorods yield higher reverse current than those with shorter nanorods due to the enhanced electric field, which is attributed to a high aspect ratio of Si nanorod.

• Journal of Biomedical Engineering Research
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• v.31 no.5
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• pp.335-343
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• 2010

This article presents a review of technologies for an endoscope. The classification according to the clinical applications and the imaging modalities are summarized. The major parts are focused on describing the gastrointestinal endoscope's structures and mechanisms. The details of the image enhanced endoscopic techniques, such as NBI (narrow band imaging), OCT (optical coherence tomography), and EUS (endoscopic ultrasound), are also explained. Finally, the trend of NOTES (natural orifice transluminal endoscopic surgery) which is new fusion technology in the field of endoscopic diagnosis and surgery is introduced.

• Journal of the Korean Vacuum Society
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• v.11 no.4
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• pp.256-260
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• 2002

Carbon nanotubes on metal(SUS304) substrates were synthesized by using micro-wave plasma-enhanced chemical vapor deposition at $650^{\circ}C$ with gas mixture CH$_4$(11%) and H$_2$(89%). Their structure was investigated by scanning electron microscopy and transmission electron microscopy. Raman spectroscopy was also used to justify the structure and crystallinity of graphite sheets. High-resolution transmission electron microscopy images clearly showed carbon nanotubes to be multwalled. The measured turn-on field and current density obtained from I-V measurement were 4.4 V/$\mu \textrm{m}$ and $8.4\times10^1\mu\textrm{A}/\textrm{cm}^2$, respectively.

• Journal of Magnetics
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• v.11 no.4
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• pp.156-159
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• 2006

We have studied the magnetic properties of the CuNi nanoparticles for three different sizes prepared by plasma and chemical techniques. The magnetization is enormously enhanced with decreasing the nanoparticle size. This enhanced magnetic moment shows almost inversely linear temperature dependence, which could be interpreted by the Langevin-type superparamagnetism. The field dependence exhibits ferromagnetic-like behavior with weak hysteresis, which could described in terms of uncompensated spin and/or surface anisotropy. In addition, the magnetic data suggest that the CuNi nanoparticles produced by the plasma method result in significantly less oxidized metallic nanoparticles than those prepared by other techniques.