• Journal of the Semiconductor & Display Technology
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• v.20 no.4
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• pp.72-77
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• 2021

The radial distribution of etch rate was analyzed using the ion energy flux model in VHF-CCP. In order to exclude the effects of polymer passivation and F radical depletion on the etching. The experiment was performed in Ar/SF6 plasma with an SF6 molar ratio of 80% of operating pressure 10 and 20 mTorr. The radial distribution of Ar/SF6 plasma was diagnosed with RF compensated Langmuir Probe(cLP) and Retarding Field Energy Analyzer(RFEA). The radial distribution of ion energy flux was calculated with Bohm current times the sheath voltage which is determined by the potential difference between the plasma space potential (measured by cLP) and the surface floating potential (by RFEA). To analyze the etch rate uniformity, Si coupon samples were etched under the same condition. The ion energy flux and the etch rate show a close correlation of more than 0.94 of R² value. It means that the etch rate distribution is explained by the ion energy flux.

• Journal of IKEEE
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• v.27 no.1
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• pp.19-24
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• 2023

Since silicon having a band gap energy of about 1.12 eV are limited to a maximum operating temperature of less than 250 ℃, the sample with MIS structure based on the SiC substrate of wide-band gap energy was manufactured and the hydrogen response characteristics at high temperatures were investigated. The dielectric layer applied here is a tantalum oxide layer that is highly permeable to hydrogen gas and shows stability at high temperatures. It was formed by RTO at a temperature of 900 ℃ with tantalum. The thickness, depth profiles, and leakage current of the tantalum oxide layer were analyzed through TEM, SIMS, and leakage current characteristics. For the hydrogen gas response characteristics, the capacitance change characteristics were investigated in the temperature range from room temperature to 400 ℃ for hydrogen gas concentrations from 0 to 2,000 ppm. As a result, it was confirmed that the sample exhibited excellent sensitivity and a response time of about 60 seconds.

• Journal of Environmental Impact Assessment
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• v.23 no.4
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• pp.251-270
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• 2014

The purpose of this study is to offer the basic data and method for assessing the naturaliness of temple environment by applying the ecological index of plant to quantitatively and objectively assess the flora and to understand the flora distributed in major temple forest. The ecological index of plant was based in the surveyed flora. The whole flora were summarized as 535 taxa including 103 families, 310 genera, 426 species, 5 subspecies, 82 varieties and 22 forms. And, the numbers of taxa in the Beopheungsa were 267 taxa, 314 taxa of the Daeseungsa and 296 taxa of the Seongjusa. The rare plants were 9 taxa including Aristolochia contorta, Viola albida, Arisaema heterophyllumand so forth, and the Korean endemic plants were 11 taxa including Clematis trichotoma, Stewartia pseudocamellia, Vicia chosenensis and so forth. The specific plants by floristic region were 51 taxa including Wistaria floribunda, Celtis aurantiaca, Angelica gigas and so forth, and the pteridophyta were 26 taxa including Osmunda japonica, Polystichum braunii, Onoclea orientalis and so forth. The naturalized plants were 35 taxa including Fallopia dumetorum, Conyza canadensis, Xanthium strumarium and so forth, the invasive alien plants were 3 taxa including Ambrosia artemisiifolia, Aster pilosus and Eupatorium rugosum. In the results of analysing the ecological index of plant in whole temple forests, RI(Rare Index) was 1.7%, 2.1% of EI(Endemic Index), 9.5% of SI(Specific Index), 1.2 of PI(Pteridophyta Index) and 6.5% of NI(Naturalized Index) in narrow sense. In broad sense, FI(Flora Index) was 11.0%, 1.5% of RI, 3.4% of EI, 4.8% of SI, 10.1% of PI, 10.9% of UI(Urbanized Index) and 25.0% of DI(Disturbed Index). The FI of the Daeseungsa was the highest among the three temple forests. In narrow sense, the RI, SI, NI and DI of the Beopheungsa was high, the seongjusa was higher the EI and SI. In broad sense, the RI and SI of the Beopheungsa, the EI, SI and PI of the Seongjusa, the UI is high in the Daeseungsa. In future, if we will analyze ecological index of plant in other temple forests, we will offer the help to establishing the plan of conservation and restoration on ecosystem in whole temple forests.Environmental Specimen Banks (ESBs) are playing pivotal role in monitoring the effect of environmental pollution on the ecosystem based on the retrospective analysis of the representative samples collected regularly and stored in cryogenic condition.

• Journal of Bio-Environment Control
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• v.16 no.4
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• pp.291-296
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• 2007

This study was conducted to investigate the effects of horizontal air flow produced by circulation fans on horizontal and vertical profiles of meteorological factors. The three-dimensional distributions of air speed, air temperature, relative humidity and carbon dioxide $(CO_2)$ concentration were measured with and without the fans in operation. The uniformity of the spatial distribution of meteorological factors decreased as the outside air temperature decreased. In "fans off" condition, spatial variations of $4.7^{\circ}C$ in air temperature, 19% in relative humidity were detected. When the fans were operated, these variations were reduced to 2.2 and 6.3%, respectively. As the fan capacity increased, the difference in air temperature among sampling points decreased. The fan capacity of $0.0104m^3{\cdot}s^{-1}{\cdot}m^{-2}$ was enough to obtain a reasonable air flow in greenhouse. The vertical profiles of air temperature and $CO_2$ concentration were reasonably uniform regardless of measurement height and fan capacity. Further researches on the position of fans to reduce the difference in air temperature along the width and the effects of using a larger number of smaller fans are required.

• Journal of the Korean Society for Nondestructive Testing
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• v.14 no.1
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• pp.7-15
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• 1994

The two-dimensional elastoplastic analysis was peformed to reveal a detail residual stress distribution of ceramic/metal joint specimen using finite element method and X-ray method. The highest tensile residual stress, ${\sigma}_x$ perpendicular to the interface appeared at the edge of the ceramic near the interface. In the vicinity of the interface, the high stress concentration occurs and residual stress distributes three-dimensionally. Therefore, the measured stress distribution differed remarkably from the result of the two-dimensional finite-element analysis. Especially at the center of the specimen near the interface, the residual stress, ox obtained from the finite element analysis was compressive, whereas X-ray measurement yielded tensile ${\sigma}_x$. Therefore, it is also attempted to investigate the finite element model for the prediction of residual stress ${\sigma}_x$ distributed nearly the interface of joint.

• the MEAT Journal
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• s.35 winter
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• pp.34-45
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• 2008

People can be exposed to various microorganisms when they eat yukae (seasoned raw meat) because yukae is eaten raw. The purpose of this study was to find out microbial distribution in yukae. In this experiment, 5 restaurants serving yukae were chosen in Daegu area. Mesophilic microorganisms and coliforms were measured by Korean Food Standards Codex. Analyses of Salmonella spp., Listeria monocytogenes, Staphylococcus aureus and Escherichia coli O157:H7 were conducted. As results, mesophilic microorganisms ranged 6.6$\times$103-2.7$\times$105 CFU/g and coliforms ranged 8.9$\times$101-2.1$\times$105 CFU/g. Salmonella spp., Listeria monocytogenes and Escherichia coli O157:H7 were not detected in all 5 samples. However, Staphylococcus aureus was detected in 1 sample out of 5 samples. Hygiene practice during production, processing and cooking process is required.

• Korean Chemical Engineering Research
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• v.44 no.3
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• pp.294-299
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• 2006

Computational simulation was performed to analyze flow velocities and particle trajectories onto the surface of bag-shaped filters with a different permeability. When the permeability of a filter is lower than that of a low-efficient fabric bag-filter widely used, the distributions of flow velocities and particle trajectories on the filter surface were not different with decreasing the filter permeability. The distributions of streamlines and radial directional gas velocities were uniform on the filter surface except for the neighbors of the bottom edge and outlet of the filter. The particle trajectories onto filter surface were more densely distributed around the bottom edge of the filter, so that the particle number on the filter surface was maximized near the bottom edge and decreased in the direction of the filter outlet.

• Journal of KIISE:Software and Applications
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• v.36 no.3
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• pp.208-216
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• 2009

A number of estimation of distribution algorithms have been proposed that do not use explicitly crossover and mutation of traditional genetic algorithms, but estimate the distribution of population for more efficient search. But because it is not easy to discover higher-order correlations of variables, lower-order correlations are estimated most cases under various constraints. In this paper, we propose a new estimation of distribution algorithm that represents higher-order correlations of the data and finds global optimum more efficiently. The proposed algorithm represents the higher-order correlations among variables by building random hypergraph model composed of hyperedges consisting of variables which are expected to be correlated, and generates the next population by Bayesian sampling algorithm Experimental results show that the proposed algorithm can find global optimum and outperforms the simple genetic algorithm and BOA(Bayesian Optimization Algorithm) on decomposable functions with deceptive building blocks.

• Nuclear Engineering and Technology
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• v.23 no.3
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• pp.316-320
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• 1991

The Core Operating Limit Supervisory System (COLSS) is digital computer based on-line monitoring system that is designed to assist the operator in monitoring of the Limiting Conditions for Operation. A current COLSS calculates axial power distribution based on in-core detector signals using 5th order Fourier series method. It was found that the 5th elder Fourier series method was not accurate for certain axial power shapes, especially saddle power shapes, resulting in thermal margin decrease. A cubic spline synthesis was applied to the COLSS in order to improve the axial power distribution monitoring for the various axial power shapes. The results showed that the cubic spline synthesis simulated more accurately the axial power shapes, up to 5% in RMS errors, compared to those of the Fourier series.

• Food Science of Animal Resources
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• v.27 no.2
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• pp.197-202
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• 2007

People can be exposed to various microorganisms when they eat yukae(seasoned raw meat) because yukae is eaten raw. The purpose of this study was to find out microbial distribution in yukae. In this experiment, 5 restaurants serving yukae were chosen in Daegu area. Mesophilic microorganisms and coliforms were measured by Korean Food Standards Codex. Analyses of Salmonella spp., Listeria monocytogenes, Staphylococcus aureus and Escherichia coli O157:H7 were conducted. As results, mesophilic microorganisms ranged $6.6{\times}10^3-2.7{\times}10^5\;CFU/g$ and coliforms ranged $8.9{\times}10^1-2.1{\times}10^5CFU/g$. Salmonella spp., Listeria monocytogenes and Escherichia coli O157:H7 were not detected in all 5 samples. However, Staphylococcus aureus was detected in 1 sample out of 5 samples. Hygiene practice during production, processing and cooking process is required.