• Journal of the Semiconductor & Display Technology
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• v.9 no.4
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• pp.71-76
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• 2010

According to recent changes in industry for semiconductor devices, a low-temperature treatment has become a necessity. These changes relate to size refinement and the development of new materials. While variation in cooling efficiency does not affect the yield when using a high-temperature treatment, uniform cooling efficiency is necessary avoid "inconsistencies/bends" in low temperature treatments. However it is difficult to increase temperature stabilization in low temperature treatments. In this paper, using CFD (Computer Fluid Dynamics), we analyze and manipulate the design and input of the low-temperature system to attempt to control for temperature variations within the quartz tube, of which airflow appears to be a predominant factor. This simulation includes variable inputs such as airflow rate, head pressure, and design manipulations in the S.C.U. (Super Cooling Unit).

• Journal of Surface Science and Engineering
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• v.34 no.5
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• pp.395-402
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• 2001

An induction thermal plasma system have been newly designed for advanced operation with a pulse modulated mode to control the plasma power in time domain and to create non-equilibrium effects such as fast quenching of the plasma to produce new functional materials in high rate. The system consists of MOSFET power supply with a maximum power of 50 kW with a frequency of 460 kHz, an induction plasma torch with a 10-turns coil of 80 mm diameter and 150 mm length and a vacuum chamber. The pulse modulated plasma was successfully generated at a plasma power of 30 kW and a high pressure of 100 kPa, with taking the on and off time as 10 ms, respectively. Measurements were carried out on the time-dependent spectral lines emitted from Ar species. The dynamic behavior of plasma temperature in a pulse cycle was estimated by the Boltzmann plot and the excitation temperature of Ar atom was found to be changed periodically from around 0.5 to 1.7 eV during the cycle. Two application regions of the induction thermal plasma newly generated were introduced to material processing with high rate synthesis based on non equilibrium effects, and to the finding of new arc quenching gases coming necessary for power circuit breaker, which is friendly with earth circumstance alternative to SF6 gas.

• Preventive Nutrition and Food Science
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• v.21 no.1
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• pp.68-72
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• 2016

To examine the possibility of using thiacremonone isolated from high-temperature-high-pressure treated garlic, this study investigated the physiological activities properties. The $IC_{50}$ values of hydroxyl, superoxide, hydrogen peroxide, and nitric oxide radical scavenging activities of thiacremonone were 92.50, 65.05, 12.60, and $81.53{\mu}g/mL$, respectively. On the other hand, the activities of vitamin C were 104.93, 99.43, 42.42, and $122.64{\mu}g/mL$, and the activities of butylated hydroxyanisole were 37.22, 68.45, 22.47, and $40.54{\mu}g/mL$, respectively. The $IC_{50}$ value of ACE inhibition activities of thiacremonone and captoprill were 0.265 and $0.036{\mu}g/mL$, respectively. The $IC_{50}$ value of xanthine oxidase inhibition activities of thiacremonone and allopurinol were 39.430 and $9.346{\mu}g/mL$, respectively. The $IC_{50}$ value of tyrosinase inhibition activities of thiacremonone and kojic acid were 101.931 and $65.648{\mu}g/mL$, respectively.

• Journal of Powder Materials
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• v.24 no.3
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• pp.216-222
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• 2017

Synthesized monocrystalline nanodiamond (nD) particles are heat-treated at various temperatures to produce highly structured diamond crystals. The heat-treated nDs show different weight loss ratios during thermogravimetric analysis. The crystallinities of the heat-treated nDs are analyzed using Raman spectroscopy. The average particle sizes of the heat-treated nDs are measured by a dynamic light scattering (DLS) system and direct imaging observation methods. Moreover, individual dispersion behaviors of the heat-treated nD particles are investigated based on ultrasonic dispersion methods. The average particle sizes of the dispersed nDs according to the two different measurement methods show very similar size distributions. Thus, it is possible to produce highly crystallized nD powder particles by a heat-treatment process, and the nD particles are relatively easy to disperse individually without any dispersant. The heat-treated nDs can lead to potential applications such as in nanocomposites, quantum dots, and biomedical materials.

• Journal of Powder Materials
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• v.11 no.4
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• pp.294-300
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• 2004

This study for preparation of aluminum nitride (AlN) with high purity was carried out by self-propagating high-temperature synthesis method in two different systems, $Al-N_{2}$ and $Al-N_{2}$-AlN, with the change of nitrogen gas pressure and dilution factor. On the occasion of $Al-N_{2}$ system, unreacted aluminum was detected in the product in spite of high nitrogen pressure, 10 MPa, This may be caused by obstructing nitrogen gas flow to inner part of molten and agglomerate of aluminum, formed in pre-heating zone. In $Al-N_{2}$-AlN system, AlN with a purity of 95% or ever can be prepared in the condition of $f_{Dil}\geq0.5$, $P_{N_{2}}\geq$ 1 MPa, and the purity can be elevated to 98% over in the condition of $f_{Dil}$ = 0.7 and $P_{N_{2}}$ = 10 MPa.

• Journal of the Society of Naval Architects of Korea
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• v.47 no.2
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• pp.225-232
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• 2010

The requirement of design of High-Pressure/High-Temperature(HP/HT) pipelines on an seabed increases in recent years. The need of research on the analysis method to improve the design capacity is increasing. The purpose of this study is the development of the analysis method of thermal buckling of subsea pipeline structures. The analysis method of thermal buckling was established by using the commercial FEM code(ABAQUS) which shows the outstanding performance in non-linear static FE analysis. The developed method has been applied to the installation of subsea pipeline on the offshore project. For a validation, the comparative study has been carried out. This application to offshore project demonstrates the superiority of the analysis method of thermal buckling of subsea pipeline structures and testifies the application to detail design.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.1192-1195
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• 2017

This paper describes the heat resistance characteristics of the imaging device installed in behind the engine due to monitoring the engine condition, and this paper includes the introduction and development of the imaging probe. Because the imaging device which is at the rear end of the engine is exposed to a high temperature and high pressure, the stability of the device should be secured by changing the device shape and supplying cooling water. The imaging probe in ADD engine test facility is installed at the rear end of the engine, and it is designed by reflecting the heat resistance characteristics to ensure the stability of the device.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.301-303
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• 2017

This study is the performance test of the vitiated air heater with high temperature and high pressure. The vitiated air heater to provide hot air about 2000 K was designed, and the performance test is carrying out. The designed vitiated air heater uses methane, oxygen, and mixing air by working gases, and uses mixing air for cooling of the bottom of a mixing head. By this reason, the vitiated ar heater has to be designed with heat-resistance from hot frame, and to be tested for its proof. In this paper the performance of he vitiated air heater is analyzed to some test results.

• Journal of the Korean Ceramic Society
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• v.52 no.2
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• pp.165-170
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• 2015

We employed the high-pressure high temperature (HPHT) process to enhance the colors of natural sapphires to obtain a vivid blue. First, we analyze the content of the coloring agent $Fe_2O_3$ using the wavelength dispersive X-ray fluorescence (WD-XRF) method. The HPHT procedure operates under 1 GPa at various temperatures of 1700, 1750, and $1800^{\circ}C$ for 5 minutes using a cubic press. We determine the color changes using the optical microscopic images, UV-VIS near-infrared (NIR) spectra, micro-Raman spectra, and Fourier transform-infrared (FT-IR) spectra for all sapphire samples before and after the treatment. The optical microscopic results indicate that the HPHT process can enhance the sapphire color to a vivid blue at temperatures above $1750^{\circ}C$. The UV-VIS-NIR spectra identify the color changes explicitly and quantitatively through providing the Lab color scales and color differences. Both results demonstrate that the colors of natural sapphires can be enhanced to a vivid blue using the HPHT process above $1750^{\circ}C$ under 1 GPa for 5 minutes.

• Journal of the Korean Society of Safety
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• v.26 no.4
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• pp.102-110
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• 2011

For decreasing of the casualties and designing of the smoke control systems in the ultra high-rise building, the programs for analysis of smoke control were developed for prediction of smoke spread and distributions of pressure and temperature in building fire situation. In this study, coupling algorithm between mass and enthalpy conservations was modified for improving the applicability of the CAU_ESCAP which program can consider the energy transfer. The fire situation in ultra high-rise building was applied by using the modified CAU_ESCAP. Results of pressure difference predicted by modified CAU_ESCAP are higher than results of ASCOS as stack effect is generated due to the increasing of stairway temperature. Moreover, theoretically, the result of the neutral plane is more accurate than the result of ASCOS, in fire situation of ultra high-rise building.