• 한국지하수토양환경학회지:지하수토양환경
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• 제22권1호
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• pp.27-32
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• 2017

Cesium (Cs) generated by nuclear accidents is one of the most hazardous radionuclides because of its gamma radiation and long half-life. Especially, when Cs is exposed on the soil environments, Cs is mainly adsorbed on the topsoil and is strongly combined with tiny soil particle including clay minerals. The adsorption of Cs onto soil can vary depending on various physicochemical properties of soil. In this study, the adsorption characteristics between soil and Cs were investigated according to various physicochemical properties of soil including organic matter contents, cation exchange capacity (CEC), soil particle size, and the types of clay minerals. Soil organic matter inhibited the adsorption of Cs onto the soil because organic matter was blocking the soil surface. In addition, it was estimated that the CEC of the soil influenced the adsorption of Cs onto the soil. Moreover, more Cs was adsorbed as the soil particles size decreased. It was estimated that Cs was mostly adsorbed onto the topsoil, this is related to the clay mineral. Therefore, soil organic matter, CEC, soil particle size, and clay minerals are considered the key factors that can influence the adsorption characteristics between soil and Cs.

• 한국토양비료학회지
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• 제44권2호
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• pp.303-305
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• 2011

A study of different levels of Nutrition Elements and the chemical properties of the soil was conducted to determine the yield performance of potato. Application of sulfur, potassium, and Magnesium significantly affected final height, dry matter content, and crispiness of potato. The final pH, organo-nitrogen, phosphorus, potassium, and magnesium content in the soil were significantly affected by S-K-Mg application.

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2008년도 Asian Magnetics Conference
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• pp.164-164
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• 2008

• 대한기계학회논문집B
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• 제33권10호
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• pp.737-747
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• 2009

This study is to investigate the effect of the moisture, volatile matter and particle size in the coal on the pulverized coal combustion characteristics using CFD. The results show that as the moisture content in coal increases, flame temperature decreases because of heat loss driven from latent heat of vaporization and reduction of heating value. As the volatile matter content in the coal increases, the temperature in the region near the burner increases, while the temperature in rear region of boiler decreases. The solution to keep the temperature in the rear region of boiler is suggested that particle size is needed to be larger. As the particle size increases, the temperature in the rear region of boiler show tendency to increase, for combustion burning time of coal could be extended.

• 한국과학교육학회지
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• 제20권2호
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• pp.262-273
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• 2000

이 연구에서는 과학의 개념 측면에서 유아교육과정,초등교육과정, 중등교육과정의 연계성 분석에 적절한 도구를 개발하고자 하였다. 교육과정의 개념적 연계성 분석을 위한 도구로 연구의 초기에는 과학의 공통소재인 '물'에 대한 개념도를 개발하였으나, 유치원부터 고등학교까지의 과학교육과정 구성 시각에 큰 차이가 있었기 때문에 통합된 개념도 개발이 어려웠다. 따라서 과학의 한 영역인 화학의 주요 학습 내용이라고 할 수 있는 '물질의 성질'에 관한 개념도를 개발하였다. 개발 절차 중에서 유아, 초등, 중등 과학교육과정에서 다루는 학습 내용의 추출, 학습 내용에 관련된 개념도를 유아 초등, 중등 과학교육과정 시각에서 개발 및 분석하는 단계는 '물'을 중심으로 개념도를 개발하는 초기 단계의 연구에 해당하고, 학습내용에 관련된 유아, 초등, 중등 과학교육과정의 내용분석, 유아, 초등, 중등 과학교육과정의 개념을 포함하는 개념도 및 분석 표 개발, 개발된 개념도 및 표의 수정 및 완성 등 세 단계는 '물질의 성질'에 관련된 후기 연구에 해당한다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 봄 학술발표회 논문집
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• pp.663-668
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• 2000

In this study, the Atterberg limit and grain-size analysis were carried for the purpose of investigating the influence on drying and organic matter of Ulsan marine deposited clay. The results revealed that Atterberg limit was decreased and grain-size distribution was variable on drying. The presence of organic matter also influenced on the physical properties of the soils. The physical properties of marine deposited clay were variable on drying, so that we recommended grain-size analysis and Atterberg limit test were performed under the wet condition of the soils after sampling.

• 천문학회보
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• 제44권2호
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• pp.53.4-53.4
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• 2019

We reconstruct the underlying dark matter (DM) density distribution of the local universe within 20Mpc/h cubic box by using the galaxy position and peculiar velocity. About 1,000 subboxes in the Illustris-TNG cosmological simulation are used to train the relation between DM density distribution and galaxy properties by using UNet-like convolutional neural network (CNN). The estimated DM density distributions have a good agreement with their truth values in terms of pixel-to-pixel correlation, the probability distribution of DM density, and matter power spectrum. We apply the trained CNN architecture to the galaxy properties from the Cosmicflows-3 catalogue to reconstruct the DM density distribution of the local universe. The reconstructed DM density distribution can be used to understand the evolution and fate of our local environment.

• 천문학회보
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• 제45권1호
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• pp.50.2-50.2
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• 2020

The dark matter (DM) only simulations have been exploited to study e.g. the large scale structures and properties of a halo. In a baryon side, the high-resolution hydrodynamic simulation such as IllustrisTNG has helped extend the physics of gas along with stars and DM. However, the expansive computational cost of hydrodynamic simulations limits the size of a simulated universe whereas DM-only simulations can generate the universe of the cosmological horizon size approximately. I will introduce a pipeline to estimate baryonic properties of a galaxy inside a dark matter (DM) halo in DM-only simulations using a machine trained on high-resolution hydrodynamic simulations. An extremely randomized tree (ERT) algorithm is used together with multiple novel improvements such as a refined error function in machine training and two-stage learning. By applying our machine to the DM-only simulation of a large volume, I then validate the pipeline that rapidly generates a galaxy catalog from a DM halo catalog using the correlations the machine found in hydrodynamic simulations. I will discuss the benefits that machine-based approaches like this entail, as well as suggestions to raise the scientific potential of such approaches.

• 월간포장계
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• 통권99호
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• pp.140-157
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• 2001

• 한국세라믹학회지
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• 제43권6호
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• pp.351-357
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• 2006

The fabrication process of the honeycomb filter was investigated using synthesized cordierite with the addition of pore former and extrusion additives (either organic matter or graphite). Also, the effect of additives on the resultant properties of honeycomb filter such as porosity, thermal expansion coefficient and mechanical strength were investigated. With increasing the organic matter up to 10 wt%, porosity was increased but compressive strength was decreased. With increasing the graphite content, however, both porosity and compressive strength were increased. The specimen with an optimum processing condition (C-17A30G, sintering at $1150^{\circ}C$) was demonstrated 59% in porosity, 69 MPa in compressive strength, and $2.4{\times}10^{-6}/^{\circ}C\;(25{\sim}1000^{\circ}C$) in thermal expansion coefficient, which physical properties are appropriate for the honeycomb filter applications.