• Journal of the Korean Geotechnical Society
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• v.37 no.1
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• pp.5-15
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• 2021

The areas consisting of frost susceptible soils in cold regions, such as the Arctic area, have problems of frost heave and thaw settlement due to the seasonal air temperature changes and internal temperature of installed structures. Ground stabilization methods for preventing frost heave and thaw settlement of frost susceptible soils include trenching, backfilling and thermo-syphon. The thermo-syphon is the method in which refrigerant can control the ground temperature by transferring the ground temperature to atmosphere in the from of two-phase flow through the heat circulation of the internal refrigerant. This numerical study applied the function of these thermo-syphon as the boundary condition through user-subroutine coding inside ABAQUS and compared and analyzed the temperature results of laboratory experiments.

• 한국연소학회:학술대회논문집
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• 2001.11a
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• pp.104-110
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• 2001

Characteristics of lifted flame for highly diluted propane with nitrogen in high temperature coflowing air have been experimentally investigated, and the stabilization mechanism of lifted flame in high temperature air coflow have been proposed. As the coflow temperature increases, the liftoff height of flame decreased due to the increase of stoichiometry laminar burning velocity. At same coflow temperature, the difference of liftoff height between the fuel mole fractions has been disappeared by scaling the liftoff velocity with stoichiometry laminar burning velocity. It has been found that lifted flame can be stabilized for even smaller fuel velocity than stoichiometry laminar burning velocity. This can be attributed to buoyancy effect and the liftoff velocity characteristics for coflow temperature support it.

• Electrical & Electronic Materials
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• v.11 no.10
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• pp.40-45
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• 1998

This paper describes a collaborative work between SEI and KEPCO on the Superconducting Magnetic Energy Storage system (SMES). We have studied two types of magnets. One is the 400kJ class LTS-SMES for testing the power stabilization operated at liquid helium temperature (4.2K) and the other is the 100J class HTS-SMES for confirming the possibility of applying HTS wire to SMES at liquid nitrogen temperature (77k). In this paper, the design of the magnet and the test results are described. Each magnet performed completely at rated operation.

• Proceedings of the Optical Society of Korea Conference
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• 2001.02a
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• pp.222-223
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• 2001

Optical parametric oscillator(OPO) has been used to generate coherent and tunable laser source with birefringent phase-matching technique in various nonlinear materials. In birefringent phase-matching, the output wavelength is controlled with angle or temperature tuning of the refractive index. However these tuning methods have several limitations such as restriction of tuning wavelength due to reasonable angular and temperature tuning ranges, Poynting vector walk-off which limits the interaction length, and thermal stabilization time. (omitted)

• Journal of the Korea Safety Management & Science
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• v.3 no.4
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• pp.45-52
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• 2001

In order to Investigate water tree degradation behavior on XLPE cable, direct voltage of 200 to 800V has been applied to the material at 5$0^{\circ}C$~10$0^{\circ}C$, and the water tree property has been correlated with voltage and temperature. The leakage current was increase as temperature increased and the Ohm's law was generally satisfied in this experiment though some experimental errors were found. The leakage current was decreased and reached to the stable state with time. It was also shown that the time for the stabilization of leakage current was lessened as voltage increased

• Proceedings of the Korean Ceranic Society Conference
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• 2003.04a
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• pp.206.1-206
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• 2003

• Journal of the Society of Cosmetic Scientists of Korea
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• v.38 no.4
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• pp.263-270
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• 2012

Ascorbic acid (Vitamin C) becomes unstable in the aqueous phase by oxygen, light and alkali, etc. The properties are limited in application to cosmetics. The most important factor that determines the destabilization of ascorbic acid in the aqueous phase was tried to understand considering its molecular deformation and degradation. In this study, we changed the polyols and emulsification technique for the stability of ascorbic acid. Then we observed the color and concentration change of ascorbic acid at room temperature and high temperature ($42^{\circ}C$) for 6 weeks and identified the stability using HPLC regularly. As a result, we found that glycerin was the most appropriate polyol for stability of the ascorbic acid. Also the technique of nonaqueous emulsification stabilized ascorbic acid than P/S emulsification. Also, P/S emulsification, glycerin was more stable than propylene glycol. By the results we suggest that ascorbic acid could be stabilized by nonaqueous emulsification method and this data could be applied to stabilization methods for cosmetic products.

• Carbon letters
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• v.25
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• pp.60-67
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• 2018

In the present work, capability of thymolphthalein-grafted graphene oxide, which was successfully synthesized in this study, in stabilization of polypropylene against thermal oxidation were investigated and compared with that of SONGNOX 1010, a commercially used phenolic antioxidant for the polymer. The modified graphene oxide were incorporated into polypropylene via melt mixing. State of distribution of the nanoplatelets in the polymer matrix was examined using scanning electron microscopy and was shown to be homogeneous. Measurements of oxidation onset temperature and oxidative induction time revealed that thymolphthalein-grafted graphene oxide modifies thermo-oxidative stability of the polymer in the melt state remarkably. However, the efficiency of the nanoplatelets in stabilization of polypropylene against thermal oxidation in melt state was shown to be inferior to that of SONGNOX 1010. Furthermore, oven ageing experiments followed by Fourier transform infrared spectroscopy showed that the modified graphene oxide improves thermo-oxidative stability of the polymer strongly in the solid state, so that its stabilization efficiency is comparable to that of SONGNOX 1010.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.8
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• pp.759-765
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• 2005

In this paper, developed isolator for gap filler is analyzed and designed using the simulation tool. Using the designed parameters, isolator is fabricated and tested in gap filler band. Temperature characteristics of isolator depend on magnet, YIG ferrite, and conductor etc. These require temperature stability and possible method of compensation for the temperature dependent effects. The temperature stabilization tries to use Ni-alloy. Developed isolator that compare with room temperature and high temperature characteristics has change fewer than 20 MHz. Implemented isolator shows more than 20 dB isolation characteristic at center frequency(2,650 MHz) and has 0.2 dB insertion loss in overall 100 MHz operating bandwidth. Return losses of input and output port are measured below -20 dB.

• Korean Chemical Engineering Research
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• v.45 no.3
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• pp.269-276
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• 2007

$TiO_2$-containing pitch fibers were prepared and various stabilization variables were investigated by characterizations of the fibers and behaviors of $TiO_2$ particles in the optimum stabilization conditions. When pitch fiber was stabilized by air at the optimum condition, the fiber weight increased as an increase of the stabilization temperature and a decrease of $TiO_2$ concentration. The carbonization yield was 71~82 wt.%, showing a decrease of the yield with the $TiO_2$ increase caused by the catalytic activity of $TiO_2$ to combustion. During the stabilization, newly developed carbonyl and carboxyl groups were introduced on the fiber surface and cross-linking reactions were progressed resulting the thermosetting property, which was verified by the replacement of hydrogen with oxygen. Pore size of the activated carbon fiber was increased by an increase in $TiO_2$ concentration. In the considerations of the aggregation behaviors of the $TiO_2$ particles, the optimum stabilization conditions of 0.5 wt.% $TiO_2$ containing petroleum-based pitch fiber were suggested as $280^{\circ}C$, 3 hr.