• Publications of The Korean Astronomical Society
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• v.30 no.2
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• pp.593-594
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• 2015

We present our analysis results for an updated orbital ephemeris for the dipping low mass X-ray binary 4U 1624-49, using the light curve collected by the All Sky Monitor (ASM) on board the Rossi X-ray Timing Explorer (RXTE) and the Monitor of All-Sky X-ray Image (MAXI). To make clear dip profiles, the light curve from the ASM and the MAXI were divided into ten 500d segments and four 400d segments for ASM and MAXI light curves, respectively, and folded with the linear ephemeris proposed by Smale et al. (2001). The phases of dip centers were determined by the method adopted from Hu et al. (2008). The phase drift was then fitted with a linear function. We obtained an updated orbital period of 0.869896(1) d and a phase zero epoch of JD 2450088.6618(57). No clear orbital period derivative is detected with a 2-sigma upper limit of $1.4{\times}10^{-6}(yr)^{-1}$ from a quadratic curve fitting of the dip phase evolution.

• Nuclear Engineering and Technology
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• v.54 no.1
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• pp.226-233
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• 2022

In the present work, a phase-field model was developed to investigate the influence of recrystallization on bubble evolution during irradiation. Considering the interaction between bubbles and grain boundary (GB), a set of modified Cahn-Hilliard and Allen-Cahn equations, with field variables and order parameters evolving in space and time, was used in this model. Both the kinetics of recrystallization characterized in experiments and point defects generated during cascade were incorporated in the model. The bubble evolution in recrystallized polycrystalline of U-Mo alloy was also investigated. The simulation results showed that GB with a large area fraction generated by recrystallization accelerates the formation and growth of bubbles. With the formation of new grains, gas atoms are swept and collected by GBs. The simulation results of bubble size and distribution are consistent with the experimental results.

• Nuclear Engineering and Technology
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• v.21 no.4
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• pp.308-320
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• 1989

The objective of this work is to investigate the effects of diminished primary coolant inventory and the presence of noncondensible gas during single- and two-phase natural circulation in a PWR loop model. The test model was composed of two loops with a U-tube heat exchanger in each loop. Through a series of tests, it has been confirmed that the two-phase natural circulation flow rates were greatly dependent on primary coolant inventory as previous investigators observed. The primary coolant inventory limit to maintain two-phase natural circulation was found to be the amount of the coolant necessary to keep the waterline of the coolant nozzle hole center in this model. The presence of noncondensible gas impede the single-phase natural circulation, but it did not affect the two-phase natural circulation significantly.

• Journal of IKEEE
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• v.19 no.3
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• pp.335-341
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• 2015

Recently a demand for high precision absolute position transducer is increasing in order to control thickness in steel industry. LVDT (linear variable differential transformer) is widely used to measure the absolute position in the linearly moving cylinder under poor factory environment. In this paper we implement the three phase LVDT with a high resolution of one micron and L/D (LVDT to digital) converter. First we designed U, V, and W three phase signaling using FPGA. Second a pulse output algorithm is designed for position information with A and B phase waveforms. Finally the performance is compared with previous sensors. Experiments show that the linearity deviation error is 0.009788 [mm] and the average sinusoidal THD is 0.0751%, which means 2.2% and 33% more improved result than the previous sensors respectively.

• 한국IT서비스학회:학술대회논문집
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• 2009.05a
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• pp.122-125
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• 2009

본 연구는 u-City에서 제공하는 u-서비스의 새로운 수익모델 창출을 위한 접근 방안으로 사용자 중심의 접근을 시도 했으며 u-서비스에 사용자가 부여하는 가치에 중점을 두고 연구를 진행하였다. 사용자가 부여한 가치의 확장을 통해 새로운 서비스 또는 수익모델 창출의 기회를 발굴하고자 하였다. 연구 결과 사용자가 부여하는 1차적인 가치는 서비스와 관련된 다양한 가치로 그 의미가 확장될 수 있었다. 확장된 가치를 근간으로 기존에 고려하지 못한 새로운 서비스와 수익모델을 발굴할 수 있는 기회를 포착할 수 있었다. u-서비스의 수익모델 창출을 위한 새로운 접근 방안으로써 사용자 가치에 대한 고려는 실질적으로 서비스를 사용할 사용자에 기초한 관점으로 사용자 중심의 u-서비스 개발 및 수익모델 발굴에 중요한 연구가 될 것이라 생각된다.

• Transactions on Electrical and Electronic Materials
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• v.5 no.5
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• pp.199-203
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• 2004

Superconducting B $i_2$S $r_2$C $a_{n-l}$C $u_{n}$ $O_{x}$(n=2～4) thin films were prepared by single target DC-magnetron sputtering. And, that was compared with the B $i_2$S $r_2$C $a_{n-l}$C $u_{n}$ $O_{x}$(n=1～3) thin film fabricated by using the ion beam sputtering. Phase intergrowth among n=2-3, 3-4 and 4-5 phases was observed. The molar fraction of each phase in the mixed crystal of the deposited films was determined by x-ray diffraction analyses and investigated as a function of $O_2$ gas pressure during sputtering. We investigated the changes of the superconducting properties by molar fraction of each phase. Also, the thin film surface observation was carried out by atomic force microscope. The images show the average particle size decreases, and the distribution density of particles on the film surface was to increase with lower gas pressures. The fabrication conditions for selective growth of the single n=2, 3 and 4 phases in BiSrC $a_{n-l}$C $u_{n}$ $O_{x}$(n=2～4) thin film are discussed.e discussed.ussed.

• 한국생물공학회:학술대회논문집
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• 2002.04a
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• pp.504-507
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• 2002

A separation/purification process for enzymatic sugar ester production was investigated The crude reaction mixture contained sugar ester and unreacted fatty acid in acetone. The reaction mixture was mixed with KOH/phosphate buffer. Hexane was then added to enhance phase separation. Three phases formed: a lower aqueous phase containing nothing of interest, a polar organic solvent middle phase that contained mostly fatty acid soaps, and a hexane-rich upper phase that contained mostly sugar ester. Distribution coefficient of each component was measured.

• Journal of the Optical Society of Korea
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• v.2 no.1
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• pp.30-33
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• 1998

We present the analysis of phase-shifted fiber Bragg gratings by coupled-mode equations. The transmission is expressed as that of a Fabry-Perot resonator with complex reflectance and complex transmittance. The transmission spectrum, the effective cavity length, and the behaviors with different phase-shifts are investigated. A very flattered transmission peak is obtained by introducing three phase-shifts in a grating.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.49 no.6
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• pp.360-366
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• 2000

This paper presents the fabrication and test of a micropump consisting of a pair of Al flap valves and a phase-change type actuator. The actuator is composed of a heater, a silicone rubber diaphragm and a working fluid chamber. The diaphragm is actuated by the vaporization and the condensation of the working fluid. The micropump is fabricated by the anisotropic etching, the boron diffusion and the metal evaporation. The forward and the backward flow characteristics of the flap valves illustrate the appropriateness as a check valve. Also, the flow rate of the micropump is measured. When the square wave input voltage of 8 V, 70% duty ratio and 2 Hz is applied to the heater, the maximum flow rate of the micropump is $97\muell/min$ for zero pressure difference.

• Journal of Embryo Transfer
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• v.28 no.3
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• pp.257-263
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• 2013

The endometrium undergoes a cyclic growth and tissue remodeling as changes of epithelial cells, and plasminogen activators (PAs) are related to endometrium tissue remodeling. This study was to evulate expression of urokinase-type plasminogen activator (uPA) and tissue-type plasminogen activator (tPA) in porcine uterine epithelial cells. In results, the uPA and tPA were expressed in uterine tissue, epithelium and secretory glands in porcine endometrial cell. In addition, the uPA and tPA were expressed in cultured epithelial cells, and it were mainly expressed in cytoplasm. In porcine uterine tissue and epithelial cells, uPA activity was higher than activity in tPA. In PAs mRNA expression levels, uPA mRNA level was significantly higher than tPA mRNA level (P<0.05). The fluorescence intensity of uPA protein was also higher than fluorescence intensity of tPA protein, and uPA protein expression was significantly higher than in tPA protein expression (P<0.05). Therefore, we suggest that a physiological function in porcine uterine epithelial cells should be more influenced by uPA than in tPA during pre-ovulatory phase.