• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.4
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• pp.363-368
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• 2010

In the solid rocket propellant combustion, the dynamic phase change from solid to liquid to vapor occurs across the melt layer. During the surface burning, liquid and gas phases are mixed in the intermediate zone between the propellant and the flame to form micro scale bubbles. The known thickness of the melt layer is approximately 1 micron at $10^5$ Pa. In this paper, we present a model of the melt layer structure and the dynamic motion of the melt front derived from the classical phase field theory. The model results show that the melt layer grows and propagates uniformly according to exp(-1/$T_s$) with $T_s$ being the propellant surface temperature.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.39 no.1
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• pp.7-15
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• 2002

This paper is concerned with remote environment monitoring & control for the breeding house as scattering far and wide. The environment data is detected in the breeding house that is collected to one processor. It's adapted to the PSTN(public switch tele-phone network) and multi-processing for exchange the environment data and the control data in between the manager and a breeding house by micro-processor. We have designed the algorithm of the communication sequence through the experimental research. This system is composed of sensor interface, FSK communications, LED display, data latch and MCS-51 single-chip. The S/W is composed with data acquisition by multi-processing, data communication and interrupt. And this paper is Proposed the DB structure algorithm concern to a mount scale using web design. The subject is a performance of effective management for the breeding house.

• Journal of the Korean Ceramic Society
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• v.34 no.2
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• pp.195-201
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• 1997

The present paper describes the effect of dry mixed grinding on kaolinite-aluminum trihydroxide mixture with a planetary ball mill before sintering and its influence on mullite formation during sintering. The size reduction of the mixture is market in the early stage of grinding and the obtained fine particles agglomerate subsequently with an increase of grinding time. The crystal structure of the mixture is collapsed easily into an amorphous one by planetary ball milling, of which amount increases with an increase of grinding time. Only mullite phase except for anatase as an inherent impurity in kaolinite appeared in the sintered body of the mixtures with mixed grinding as relatively lower temperature 1523K, while corundum, cristobalite, and Al-Si spinel phases, besides mullite were formed in the sintered body of the mixture without mixed grinding. Therefore, the mixed grinding treatment is very effective to improve the homogeneous mixing and disp-ersion of the mixture of raw materials on a micro scale and to decrease the thermal decomposition tem-perature by crystal structure change of them so as to obatin direct preparation of mullite with high purity at relatively low temperature.

• Korean Journal of Plant Tissue Culture
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• v.27 no.1
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• pp.25-29
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• 2000

Liquid shaking culture was conducted to investigate the proper culture conditions for the micropropagation of high quality lily using bulblets (3 mm in diameter) obtained from small scale culture. The combinations of 9% sucrose and 10 mM nitrogen or 6% sucrose and 20 mM $NH_4NO_3$ were effective on the growth and weight of micro-bulbs. However, the number of new bulbs was the highest when 20 to 40 mM $NH_4NO_3$ and 3% sucrose were added to the MS medium. The total fresh weight was increased effectively in MS medium supplemented with BA 0.2 mg/L alone under $60\;{\mu}mol{\cdot}m^2{\cdot}sec^{-1}$ intensity. Also bulblet weight was increased at $60\;{\mu}mol{\cdot}m^2{\cdot}sec^{-1}$ intensity, regardless of BA concentrations (0.2 and 2 mg/L) in the medium. The proper culture period of bulblet was about 2 month in liquid shaking culture.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.8 s.173
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• pp.165-173
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• 2005

This paper presents the results for deposition of micrometer-scale metal lines on glass for the development of TFT-LCD circuit repair-system. Although there had been a few studies in the late 1980's for the deposition of metallic interconnects by laser-induced chemical vapor deposition, those studies mostly used continuous wave lasers. In this work, a third harmonic Nd:YLF laser (351nm) of high repetition rates, up to 10 KHz, was used as the illumination source and W(CO)s was selected as the precursor. General characteristics of the metal deposit (tungsten) such as height, width, morphology as well as electrical properties were examined for various process conditions. Height of the deposited tungsten lines ranged from 35 to 500 m depending on laser power and scan speed while the width was controlled between 50um using a slit placed in the beam path. The resistivity of the deposited tungsten lines was measured to be below $1{\Omega}{\cdotu}um$, which is an acceptable value according to the manufacturing standard. The tungsten lines produced at high scan speed had good surface morphology with little particles around the patterns. Experimental results demonstrated that it is likely that the deposit forms through a hybrid process, namely through the combination of photolytic and pyrolytic mechanisms.

• Textile Coloration and Finishing
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• v.30 no.3
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• pp.190-198
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• 2018

We fabricated high transmission and high scattering poly(ethylene-co-vinyl acetate)(EVA) films embedding $SiO_2$ nanoparticles to improve outcoupling efficiency in organic display. The 800nm diameter $SiO_2$ nanoparticles aggregated and formed $1.56{\mu}m$ (with ${\pm}0.853{\mu}m$ standard deviation) diameter microparticles in EVA. The total transmission of scattering film was 83.3% on Polyethylene terephthalate(PET), which was higher than reference 82.8% PET substrate. The diffuse transmission and haze of the $SiO_2$ embedded EVA film were 76.1% and 91.4%, respectively. The optimized condition was 1:1 weight ratio of $SiO_2$ nanoparticles to EVA in Tetrahydrofuran(THF) solution. When the ratio of $SiO_2$ was larger than 1, the total transmission decreased by the increase in backscattering of light due to high scattering. With the optimized condition, we could succeed to fabricate a large scale film(35m in length) with a roll-to-roll process.

• Economic and Environmental Geology
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• v.39 no.4 s.179
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• pp.495-505
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• 2006

Atmospheric infrasound is defined as low frequency inaudible sound waves generated from natural phenomena and human activities. One property of long-distance travelling of infrasound makes it possible to detect the wave propagated from remote sound sources and to understand many geophysical phenomena generating it. Recently, advanced global infrasound sensor arrays are being deployed to monitor the clandestine nuclear test and to study geophysical phenomena in the world. In Korea, five seismo-acoustic arrays consisting of co-located seismometer and micro-barometer have been operated to discriminate the artificial explosions from the natural earthquakes in and around the Korean Peninsula. In addition to the discrimination purpose, these ways also record distinct infrasonic signals from natural phenomena on global scale such as large earthquake, bolide event, volcanic explosion, typhoon, and so on. As a new frontier in monitoring the earth, infrasound is being applied to understand various phenomena in and above the earth's surface.

• Korean Journal of Veterinary Research
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• v.29 no.4
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• pp.567-575
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• 1989

This study was conducted to evaluate the possibility of application of a microenzyme-linked immunosorbent assay(micro-ELISA) for the serodiagnosis of specific toxoplasma antibodies in swine sera and this test was performed as a microplate system by coating the polystyrene plates with toxoplasma soluble antigen, incubated serially diluted sera, then added horse radish peroxidase labelled goat anti-swine IgG(r) conjugate followed by o-phenylenediamine as substrate. The color development by enzyme-substrate reaction was determined by the photometric reading [ELISA reader at 490nm (OD)] and visual reading. The soluble antigen was prepared from the tachyzoites in mouse peritoneal cavity. A total of 1,200 swine sera from pig slaughter-house and a total of 116 swine sera from pig breeding station (S-C farm) were tested for the detection of antibodies to Toxoplasma gondii. The results obtained were summarized as follows: 1. The optimal reactions of indirect ELISA for the test sera were determined by the dilution of antigen 1:256 and 1:3,200 of horse radish peroxidase conjugate [anti-swine IgG(r)]. 2. The specific togoplasma antibody(IgG) in pigs infected with Tp artificially were detected as the serum titers of 1:64 or 1:128 at one week postinfection. 3. Of a total of 1,200 swine sera from pig slaughter-house 505 samples of sera were detected as positive (42.1%) and of a total of 116 swine sera from S-C pig breeding station 68 samples of sera as positive (58.6%). 4. The specific antibody(IgG) detection rates against a total of 1,200 test sera from pig slaughter-house were not significant between male (43.1%) and female (40.7%). 5. The indirect ELISA was proved to be a sensitive and specific procedure for the serodiagnosis of swine toxoplasmosis and also evaluated as an effective screening test for the large scale of test samples in laboratory.

• Journal of the Microelectronics and Packaging Society
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• v.14 no.3
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• pp.29-36
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• 2007

The main objectives of this study are to investigate the micro-scale energy transfer mechanism for silicon wafer and to find an efficient way for fabrication of silicon wafer through-hole by using the femtosecond pulse laser ablation. In addition, the electron-phonon interactions during laser irradiation are discussed and the carrier number density and temperatures are estimated. In particular, the present study observes the shapes of silicon wafer through-hole with $100\;{\mu}m$ diameter and it also measures the heat-affected area and the ablation depths fur different laser fluences by using the optic microscope and the three-dimensional profile measurement technique. First, from numerical investigation, it is found that the nonequilibrium state exists between electrons and phonons during laser irradiation. From experimental results, it should be noted that the heat-affected area increases with laser fluence, and the optimal conditions for through-hole formation with minimum heat affected zone are finally obtained.

• Journal of the Korean Geotechnical Society
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• v.21 no.2
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• pp.5-16
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• 2005

Tn this study, model soil deposits are prepared in large test chambers to minimize the scale effects. Also, slurry of mixture containing 50 percent kaolin clay and 50 percent silica has been consolidated to simulate the process of natural soil deposit formation and to reduce the consolidation time. To provide a more detailed description of varying soil properties along the soil profile of model clay deposits and to compare the in-situ test results with those from prototype tests, miniature in-situ tests, including vane shear, piezoprobe, and cone penetration tests were conducted in each of the clay deposits. The current results indicate that consistent soil deposits were prepared for the current and previous test programs. Also, reasonable predicting methods of prototype behavior based on model in-situ test results were suggested in this study by examining differences between the test results from both the model and prototype tests.