• Journal of Radiation Protection and Research
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• v.18 no.2
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• pp.71-79
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• 1993

Form the pure Maxwellian distribution(kT= 1.42MeV), the effects upon calibration factors of encapsulating a $^{252}Cf$ spontaneous fission neutron source were investigated to establish a standard neutron field in the Secondary Standard Dosimetry Laboratory at Korea Atomic Energy Research Institute(KAERI). A Monte Carlo code MCNP was used in simulating the encapsulation SR-Cf-100 and SR-Cf-1273 to be real conditions. The anisotropy(FI) and fluence-to-dose equivalents conversion factors$(H/{\Phi})$ were evaluated and compared with other results. As the results, the FI was determined to be 1.061 at ${\theta}=90^{\circ}$ with ${\pm}0.2%$ statistical error and the $(H/{\Phi})$ was evaluated to be $333.9 [pSv\;cm^2]\;with\;{\pm}0.5%$ statistical error, which is lower by 1.8% than that recommended by the ISO 8529. This means physically that the neutron spectrum of the unmoderated $^{252}Cf$ source in KAERI is a little more softened than that by the ISO.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.54 no.1
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• pp.61-79
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• 2009

This study is for incompatible element contents of Perilla frutescens and Sesamum indicum from the Keumsan: biotite granite, phyllite and shale areas. In the soils, high elements are shown in the granite and phyllite areas, and in the areas of the Perilla frutescens. Positive correlations are distinctive within the granite for the Perilla frutescens, but the shale for the Sesamum indicum. These relationships can be explained with relative propositions of minerals containing the incompatible element. In the plants, high elements are shown in the shale and the Sesamum indicum are high in the comparisons of the same soil types. The low parts are mainly high. Regardless of the soil types, the lower and upper parts, respectively, are high in the Y, Zr and Rb contents for the Perilla frutescens, but, Ta, Nb, Th and U contents for the Sesamum indicum. Positive correlations are distinctive within plants of the phyllite. Comparing with the soil types, all HFS and Cs contents of the LFS in the plants are low with differences of several to hundred times, but high in the Sr contents with differences of several times. In the comparisons between plants and soil types, Y, Zr, Hf, Ta, Nb, Rb, and Sr of the phyllite and Th, U, Ba and Cs of the shale for the Perilla frutescens as well as Y, Zr, Hf, Rb, Sr, Ba and Cs of the phyllite and Ta, Nb, Th and U of the shale for the Sesamum indicum are chemically similar to the soils. In the comparisons of the each parts for the plant types, differences with the soils are big in the granite.

• Journal of Korea Foundry Society
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• v.31 no.2
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• pp.79-82
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• 2011

Various grain refining alloying elements such as Sr, TiB, and Ca were added to AZ91D and their effects on the mechanical properties and mold filling ability were investigated. The average grain sizes of those alloys were significantly reduced by the small amounts of the alloying elements. Ca addition was the most remarkably effective in reducing the grain size, however it was found to deteriorate the mold filling ability and tensile properties. TiB addition was observed to be the most efficient for both grain refinement and mold filling.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.77-79
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• 1999

Bi$_2$Sr$_2$CaCu$_2$O(Bi-2212) thick films were fabricated on Y211 substrate by screen printing method. The aim of the study was to fabricate superconducting thick films on Y211 substrate by MPMG process. For this study, patterned samples by screen printing method were heated with MPMG process. The thickness of Bi2212 on substrate was about 20 ${\mu}{\textrm}{m}$ and these samples showed many Bi- 2212 phases.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.30 no.1
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• pp.79-86
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• 2016

In this paper, we propose a current-driven synchronous rectifier driver circuit for LLC resonant half-bridge converters. The proposed driver circuit detects a relatively low current in the primary side of the transformer although a large current is flowing in the secondary side. Due to this feature, the driver circuit has a simple circuit structure and stabilizes the switching operation with a logic-level switching voltages for the synchronous rectifier. The operation and performance of the proposed driver circuit are confirmed with a prototype of 1kW class LLC resonant half-bridge converter. The experimental results proved that the proposed synchronous rectifier driver method improves the power conversion efficiency by around 1% and reduces the internal power loss by 17W.

• Proceedings of the Korean Society of Computer Information Conference
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• 2022.07a
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• pp.79-80
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• 2022

본 논문에서는 데이터 증강 기법 중 하나인 EDA를 적용하여 BERT 기반의 감성 분류 언어 모델을 만들고, 성능 개선 방법을 제안한다. EDA(Easy Data Augmentation) 기법은 테이터가 한정되어 있는 환경에서 SR(Synonym Replacement), RI(Random Insertion), RS(Random Swap), RD(Random Deletion) 총 4가지 세부 기법을 통해서 학습 데이터를 증강 시킬 수 있다. 이렇게 증강된 데이터를 학습 데이터로 이용해 구글의 BERT를 기본 모델로 한 전이학습을 진행하게 되면 감성 분류 모델을 생성해 낼 수 있다. 데이터 증강 기법 적용 후 전이 학습을 통해 생성한 감성 분류 모델의 성능을 증강 이전의 전이 학습 모델과 비교해 보면 정확도 측면에서 향상을 기대해 볼 수 있다.

• Membrane and Water Treatment
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• v.9 no.5
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• pp.327-334
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• 2018

The nano/micro composites with highly porous surface area have attracted of great interest, particularly the synthesis of porous and thin film sheets of high performance. In this paper, an easy method of cost-effective synthesis of thin film ceramic fiber membranes based on Hydroxyapatite, and activated carbon by turned into studied to be applied within the service-facilitated the transport of radioactive waste such as $^{90}Sr$, $^{137}Cs$ and $^{60}Co$) as activated product of radioisotopes from ETRR-2 research reactor and dissolved in 3M $HNO_3$, across a thin flat-sheet supported liquid membrane (TFSSLM). Radionuclides are transported from alkaline pH values. The presence of sodium salts in the aqueous media improves in $HNO_3$, the lowering of permeability because the initial $HNO_3$ concentration is improved. The study some parameters on the thin sheet ceramic supported liquid membrane. EDTA as stripping phase concentration, time of extraction and temperature were studied. The study of maximum permeability of radioisotopes for all parameters. The pertraction of a radioactive waste solution from nitrate medium were examined at the optimized conditions. Under the optimum experimental 98.6-99.9% of $^{90}Sr$, 79.65-80.3% of $^{137}Cs$ and $^{60}Co$ 45.5-55.5% in 90-110 min with were extracted in 10-30 min, respectively. The process of diffusion in liquid membranes is governed by the chemical diffusion process.

• Journal of The Korean Society of Grassland and Forage Science
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• v.15 no.1
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• pp.73-79
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• 1995

A simple conservation technique baled silage making of selected froage materials was discussed in Suwon and in Muan county during 1991 - 1992. Eleven species of forage crops and pasture grasses(maize. sorghum, pearl millet, barnyardgrass, rye, barley, spring oat, Italian ryegrass, orchardgrass, alfalfa and grass-legume pasture mixtures) were harvested at different growth stage from young plant to maturity and baled in a self constructed square baling chamber, and wrapped in a 0.05mm thick polyethylene plastic film. Each bales measured by 90cm long, 60cm wide and 50cm height and weighted between 15~20kg in dry matter basis. physio-molphologcal characteristics of the plants, leaf weight ratio(LWR), leaf area ratio(LAR), stalk ratio (SR), stalk hardness(SH) and other growth parameters, were analysed and were used as a parameter to evaluate the suitability of materials for baling. Italian ryegrass including orchardgrass, alfalfa and pasture mixtures produced high quality baled silage. Silage quality point(F1ieg-point) of Italian ryegrass was improved from 63 point in crushed custom silage to 75 piont in baled silage. Meterial of grass-legume pasture mixtures showed 55 point in crushed silage and 67 point in baled silage. Fodder rye, barley, spring oat and barnyardgrass were also evaluated as a good materials for baled silage making. On the other hand, meize including sorghum and peral millet were evaluated as a not suitable materals for baling due to its high value of SR and SH. Quality of maize was excellent with 88 point in clushed silage and medium with 47 point in baled silage making.

• The Journal of Pediatrics of Korean Medicine
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• v.26 no.1
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• pp.60-69
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• 2012

Background Children's Eating Behaviour Questionnaire (CEBQ) is a parents-targeted questionnaire to measure eating behavior of children, developed in United Kingdom and verified validity and reliability in several countries. Validity of Korean version of CEBQ (K-CEBQ) was verified in 2009. Objectives The study was conducted to assess the appetite improvement after herbal treatment in children who have anorexia. Methods The parents of the 26 children(anorexia 11, non-anorexia 15; $79.54{\pm}38.17$ months) who visited one university hospital was surveyed using K-CEBQ from April 2010 to April 2011. It was re-surveyed at intervals of 3 months. Differences between the anorexia group and the non-anorexia group were analyzed by Mann-Whitney U test, and comparisons of pre-treatment and post-treatment in anorexia group and non-anorexia group were verified by Wilcoxon signed-rank test. Results Depends on the presence of anorexia in child, Slowness in eating/Satiety responsiveness (SE/SR), Enjoyment of food (EF), Emotional undereating (EUE) and total scores were significantly different ($p$<0.05). Also, there were significant difference in SE/SR and total scores before and after the herbal treatment in anorexia group (p<0.05), and all scores tended to increase a few. However there were no significant difference before and after the herbal treatment in non-anorexia group, and the scores except for Desire to drink (DD) and Emotional overeating (EOE) were decreased. Conclusions Herbal treatment in children who have anorexia has improved their appetite in terms of eating sensitivity.

• Progress in Superconductivity
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• v.5 no.1
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• pp.75-79
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• 2003

YBCO films were deposited with various thicknesses from 100nm to 1.6$\mu\textrm{m}$ on single crystal $SrTiO_3$ substrates by pulsed laser deposition (PLD). The effects of different deposition conditions, especially different deposition rates by means of changing the pulsed laser frequency up to 200Hz, on the J$_{c}$ value were studied. For YBCO film with the thickness of 200nm, the $J_{c}$ value of $2.1MA/\textrm{cm}^2$ has been achieved under the high deposition rate of 3.2nm/s (190nm/min). The $J_{c}$ can be maintained greater than $1M/\textrm{cm}^2$ with the thickness less than 1$\mu\textrm{m}$. The X-ray analysis was used to examine the texture, crystallization and surface quality. The SEM was employed to analyze the surface of YBCO, and it was shown the surface of YBCO film became rougher with increasing the thickness. There were many large singular outgrowths and networks of outgrowths on the surface of YBCO films which lowered the density of thick YBCO film. The outgrowth network was probably the a-axis YBCO corresponding to XRD $\theta$-2$\theta$scan and $\chi$-scan which were used to characterize a-axis orientation of YBCO film. The reason for J$_{c}$ declining with increasing the thickness was studied and discussed.sed.