• Journal of the Korean Society for Precision Engineering
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• v.18 no.4
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• pp.182-189
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• 2001

TiCN based submicron cermet and similar ISO grad of the conventional cermets with TiCN of different particle size were produced by PM process, and their microstructure, mechanical properties and cutting performance were compared. The microstructure of submicron cermet was more homogeneous and showed much finer microstructure, resulting in better hardness and fracture toughness. The submicron cermet tools achieved excellent cutting performance such as wear resistance and toughness in comparison with two grades of the conventional cermets in millimg test. The relationship between microstrucure, mechanical properties and cutting performance of these cermet tools was discussed. The submicron cermet tools revealed for their potential to wide application range and interrupt cutting because of their superior wear resistance and toughness combinations.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.30A no.11
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• pp.122-131
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• 1993

In this paper, we have developed a submicron Si MOSFET simulator, which is physically based on the hydrodynamic energy transport mode. The simulator was used to investigate the nonstationary transport effects and the transient phenomena in submicron Si MOSFET's. It is found that the velocity overshoot and the carrier heating are dominant transport mechanism near the drain end of the channel and the transient phenomena is more retained in a long channel MOSFET.

• Transactions on Electrical and Electronic Materials
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• v.4 no.1
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• pp.29-33
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• 2003

Europium doped yttrium oxide submicron-sized particles were prepared by ultrasonic aerosol pyrolysis. To examine the size effect of submicron-sized-particle, the photoluminescence of the particles was investigated. The particle size was controlled by pH, reaction temperature, molar concentration of yttrium in precursor solution. The PL intensity of submicron-sized particles was decreased with particles size. When the particle size is above about 150 times of Bohr radius of Y$_2$O$_3$, the optical property of the particles shows the bulk characteristics.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2116-2121
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• 2008

Removal of particles at rich $CO_2$ condition has been important in the gas cleaning for $CO_2$ capture in Oxy-fuel combustion. Electrostatic precipitators (ESPs) have been widely used to remove particles in exhaust gases from present air combustion. However, few studies on characteristics of ESPs under a $CO_2$ rich gas condition have been conducted. In this study, we investigated integration of electrostatic precipitators (ESP) for removing submicron particles along with corona discharge characteristics and collection efficiency of submicron particles at $CO_2$ rich condition. The overall performance of ESP is represented by collection efficiency as function of energy consumption. The experiment results showed that higher the concentration of $CO_2$ gas, the corona discharge currents were lower at the same applied voltages and the spark over occurred at lower voltages, and the collection efficiency of submicron particles under 50, 80% $CO_2$ conditions was much lower than that under 100% Air.

• Korean Journal of Materials Research
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• v.13 no.8
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• pp.485-490
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• 2003

We have developed a new way of the constant growth technique to maintain a grating height of originally-etched V-groove of submicron gratings up to 1.5 $\mu\textrm{m}$ thickness by a low pressure metalorganic chemical vapor deposition. The constant growth technique is well performed on two kinds of submicron gratings that made by holography and electron (e)-beam lithography GaAs buffer layer grown on thermally deformed submicron gratings has an important role in recovering the deformed grating profile from sinusoidal to V-shaped by reducing mass transport effects. The thermal deformation effect on submicron gratings made by e-beam lithography is less than that on submicron gratings made by holography. The constant growth technique is an important step to realize complex optoelectronic devices such as one-step grown distributed feedback lasers and two-dimensional photonic crystals.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2012.05a
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• pp.211-212
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• 2012

ZnO submicron particles were grown on Au-catalyzed Si substrate by a vapor phase transport (VPT) growth process under different mixture gas ratio at growth temperature of $900^{\circ}C$. The structural and optical properties of the ZnO submicron particles were investigated by field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), and photoluminescence (PL). The ZnO submicron particles could be clustered with the $O_2/Ar$ mixture gas ratio(%) higher than 10%, and it was mainly determined by the gas ambient. Particularly, when the $O_2/Ar$ mixture gas ratio was 30%, it was observed the ZnO submicron particles with diameters in the range of 125 to 500 nm and the narrowest full width at half maximum (FWHM) of XRD and PL spectra with $0.121^{\circ}$ and 92 meV, respectively. It was found that the structural and optical properties of the ZnO submicron particles were improved with increasing the $O_2/Ar$ mixture gas ratio through the XRD and PL spectra.

• Journal of Plant Biotechnology
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• v.49 no.3
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• pp.257-270
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• 2022

The aim of this work was to prepare a new biodegradable polyhydroxybutyrate (PHB) submicron fiber mat loaded with hypericin-rich Hypericum perforatum raw extract by centrifugal spinning technology, an alternative approach to the traditional method of electrospinning to fabricate nanofibers or microfibers from solutions at high speed and low cost. Hypericins in methanol/acetone extract of H. perforatum were determined by UHPLC-MS/MS and HPLC/PDA. Submicron fiber mats composed of pure PHB or PHB enriched with H. perforatum extract were prepared using a pilot plant demonstrator for the centrifugal spinning technology and characterized by SEM. Singlet oxygen production was quantified by the 1,3-diphenylisobenzofuran (DPIBF) method in hexane. The results proved a significant production of singlet oxygen by the prepared submicron fiber mat. We also found a significant antibacterial activity against the bacterial strain Escherichia coli CCM 5417 by a method in accordance with JIS Z 2801/ISO 22196 standards. The H. perforatum extract-enriched PHB submicron fiber mats showed potential for the development of self-cleaning and antimicrobial air filters.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 1994.10b
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• pp.23-23
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• 1994

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.1201-1206
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• 2004

Sonoluminescence (SL) characteristics such as pulse shape, radiance and spectrum radiance from submicron bubbles were investigated. In this study, a set of analytical solutions of the Navier-Stokes equations for the gas inside bubble and equations obtained from mass, momentum and energy equations for the liquid layer adjacent the bubble wall were used to estimate the gas temperature and pressure at the collapse point, which are crucial parameters to determine the SL characteristics. Heat transfer inside the gas bubble as well as at the liquid boundary layer, which was not considered in the most of previous studies on the sonoluminescence was taken it into account in the calculation of the temperature distribution inside the bubble. It was found that bremsstrahlung is a very possible mechanism of the light emission from either micron or submicron bubbles. It was also found that the peak temperature exceeding $10^{6}$ K in the submicron bubble driven at 1 MHz and 4 atm may be due to the rapid change of the bubble wall acceleration near the collapse point rather than shock formation.

• Proceedings of the Optical Society of Korea Conference
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• 1991.06a
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• pp.81-87
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• 1991

A design of a four-mirror optical system for submicron lithography using KrF excimer laser beam(λ=248nm) is presented. By using the third order aberration theory, analytic solutions for a telecentric, flat-field, and anastigmatic four-spherical-mirror system (reduction magnification 5$\times$) are found. Aspherization is carried out to the spherical mirror surfaces in order to reduce the residual higher order aberrations and vignetting effect. Finally we obtain a reflection system useful in submicron lithographic application.