• 국제초고층학회논문집
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• 제1권3호
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• pp.155-167
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• 2012

This paper introduces the outlines of review and approval processes, general criteria and usual practices taken in Japan for the seismic design of high-rise buildings. The structural calculations are based on time-history analyses followed by performance evaluations. This paper also introduces structural design of two high-rise buildings: one is a 100 m high reinforced concrete residential building, and the other is a 300 m high steel building for mixed use.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1996년도 춘계학술발표회논문집(1)
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• pp.46-51
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• 1996

In this study we calculate the infite multiplication factors ($k_{\infty}$) and the Doppler temperature coefficients (DTC) of two mixed-oxide (MOX) fuel rods with different plutonium contents by using PHOENIX-P, HELIOS and CASMO-3 codes. The results were compared against the reference values obtained by MCNP-3A continuous-energy Monte Carlo code. The purpose of this study is to benchmark the accuracy of these lattice codes. The PHOENIX-P's Doppler coefficients calculated were in good agreement with the MCNP results within the Monte-Carlo uncertainty band which is in the order of $\pm$ 10% for the Doppler coefficients..

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1996년도 춘계학술발표회논문집(1)
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• pp.40-45
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• 1996

A new concept of equivalent homogenization is proposed. The concept employs new set of homogenized parameters: homogenized cross sections (XS) and interface matrix (IM), which relates partial currents at the celt interfaces. The idea of interface matrix generalizes the idea of discontinuity factors (DFs), proposed and developed by K.Koebke and K.Smith. The method of K.Smith can be simulated within framework of new method, while the new method approximates heterogeneous cell better in case of the steep flux gradients at the cell interfaces. The attractive shapes of new concept are: improved accuracy, simplicity of incorporation in the existing codes, equal numerical expenses in comparison to the K.Smith's approach. The new concept is useful for: (a) explicit reflector/baffle simulation; (b) control blades simulation; (c) mixed UO2/MOX core simulation, The offered model has been incorporated in the finite difference code and in the nodal code PANBOX. The numerical results show good accuracy of core calculations and insensitivity of homogenized parameters with respect to in- core conditions.

• Journal of Electrochemical Science and Technology
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• 제12권3호
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• pp.365-376
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• 2021

Two arylamino substituted mercaptoimidazole derivatives namely 4,5-dimethyl-1-(phenylamino)-1H-imidazole-2(3H)-thione (I1) and 4,5- dimethyl-1-((p-chlorophenyl)amino)- 1H-imidazole-2(3H)-thione (I2) were synthesized and investigated as corrosion inhibitors for carbon steel in 0.5 M HCl solution by means of electrochemical impedance spectroscopy (EIS), potentiodynamic polarization, ATR-FTIR spectroscopy and SEM. The results showed that the investigated mercaptoimidazole derivatives act as mixed type inhibitors and inhibition efficiency follows the I2>I1 order. Adsorption of inhibitors on metal surface was found to obey the Langmuir adsorption isotherm. Thermodynamic parameters revealed that adsorption of the inhibitors has both physisorption and chemisorption adsorption mechanism. Electrochemical test results were supported by quantum chemical parameters obtained from DFT calculations.

• East Asian mathematical journal
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• 제40권2호
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• pp.267-286
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• 2024

This study investigates the perceptions toward prospective elementary teachers regarding the revised 2015 elementary mathematics curriculum. The aim is to understand the importance and implementation of the revised curriculum and provide implications for curriculum improvement in elementary teacher education institutions, using Interpretative Phenomenological Analysis (IPA). The research findings are as follows: Firstly, prospective elementary teachers perceived that the areas of the revised 2015 elementary mathematics curriculum that require particular focus are number and operations and data and probability. Secondly, they identified the specific elements within these areas that demand dedicated attention as follows: numbers up to four digits in number and operations, mixed calculations with natural numbers, shapes of solid figures, spatial sense of solid figures, comparison of quantities in measurement, etc. These findings can inform the improvement of the curriculum in elementary teacher education institutions.

• 한국초등수학교육학회지
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• 제24권2호
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• pp.207-229
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• 2020

본 연구에서는 프랑스와 우리나라의 초등 수학교육 비교를 위하여 일반적인 초등수학교육 체계, 수학 교육과정의 문서 체계, 수와 연산 영역을 중심으로 수학 교육과정의 지도 내용의 특징을 살펴보았다. 초등학교 6학년 수학 수업 시수는 프랑스가 우리나라보다 약 5% 더 많이 배우고 있고, 수학 교육과정 문서는 전반적으로 우리나라보다 더 구체적인 특성을 보인다. 수와 연산 영역 교육과정의 비교 결과 특히 혼합계산과 분수의 계산에서 많은 차이가 있었다. 본 연구를 통하여 수학 교육과정 문서의 구체화와 학교 수학적 관점에서 허용되는 구체적인 사례 제시, 분수의 계산 중에서 특히 분수의 나눗셈의 지도 시기와 방법에 대한 연구의 필요성을 제안하였다. 마지막으로 초등 수학에서 계산의 중요성과 지도 방법에 대한 재고가 필요함을 제안하였다.

• Nuclear Engineering and Technology
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• 제52권12호
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• pp.2733-2742
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• 2020

This paper presents an assessment of applicability of the multigroup cross sections generated with Monte Carlo tools to the fast reactor analysis based on transport calculations. 33-group cross section sets were generated for simple one- (1-D) and two-dimensional (2-D) sodium-cooled fast reactor problems using the SERPENT code and applied to deterministic steady-state and depletion calculations. Relative to the reference continuous-energy SERPENT results, with the transport corrected P₀ scattering cross section, the k-eff value was overestimated by 506 and 588 pcm for 1-D and 2-D problems, respectively, since anisotropic scattering is important in fast reactors. When the scattering order was increased to P₅, the 1-D and 2-D problem errors were increased to 577 and 643 pcm, respectively. A sensitivity and uncertainty analysis with the PERSENT code indicated that these large k-eff errors cannot be attributed to the statistical uncertainties of cross sections and they are likely due to the approximate anisotropic scattering matrices determined by scalar flux weighting. The anisotropic scattering cross sections were alternatively generated using the MC²-3 code and merged with the SERPENT cross sections. The mixed cross section set consistently reduced the errors in k-eff, assembly powers, and nuclide densities. For example, in the 2-D calculation with P3 scattering order, the k-eff error was reduced from 634 pcm to -223 pcm. The maximum error in assembly power was reduced from 2.8% to 0.8% and the RMS error was reduced from 1.4% to 0.4%. The maximum error in the nuclide densities at the end of 12-month depletion that occurred in ²³⁷Np was reduced from 3.4% to 1.5%. The errors of the other nuclides are also reduced consistently, for example, from 1.1% to 0.1% for ²³⁵U, from 2.2% to 0.7% for ²³⁸Pu, and from 1.6% to 0.2% for ²⁴¹Pu. These results indicate that the scalar flux weighted anisotropic scattering cross sections of SERPENT may not be adequate for application to fast reactors where anisotropic scattering is important.

• 한국수학교육학회지시리즈C:초등수학교육
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• 제21권3호
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• pp.289-307
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• 2018

자연수의 혼합 계산은 초등학교에서 자연수의 사칙 계산을 완성하는 측면에서 중요한 내용임에도 불구하고, 그 지도 방안에 대한 연구가 많지 않다. 본 연구는 자연수의 혼합 계산과 관련하여 국내의 5차부터 2009 개정 수학 교과서와 국외(일본, 싱가포르) 교과서를 크게 괄호와 연산 순서에 초점을 두어 분석하였다. 분석 결과, 괄호를 명시적으로 제시한 횟수와 괄호 도입 시기 및 표현 방법에서 교육과정별로 교과서의 제시 방식에 차이가 있었다. 연산 순서와 관련하여 국내 교과서는 대체로 실생활 맥락을 활용하고 있었고 연산 순서를 도식화하여 표현하는 경우와 그렇지 않은 경우가 있었다. 반면, 싱가포르 교과서는 연산 순서를 직접적으로 제시하고 계산기 활용을 강조하는 측면이 있었으며, 일본은 실생활 맥락을 활용하면서 동시에 연산의 위계 지도를 제시하고 있었다. 이러한 분석 결과를 바탕으로 자연수의 혼합 계산에 대한 지도 방안 및 후속 교과서 개발에 대한 시사점을 논의하였다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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• pp.407-408
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• 2011

Natural boron consists of two stable isotopes 10B and 11B with natural abundance of 18.8 atom percent of 10B and 81.2 atom percent of 11B. The thermal neutron absorption cross-section for 10B and 11B are 3837 barn and 0.005 barn respectively. 10B enriched specific compounds are used for control rods and as a reactor coolant additives. In this work 2 methods for boron enrichment were analysed: 1) Gas irradiation in static conditions. Dissociation occurs due to multiphoton absorption by specific isotopes in appropriately tuned laser field. IR shifted laser pulses are usually used in combination with increasing the laser intensity also improves selectivity up to some degree. In order to prevent recombination of dissociated molecules BCl3 is mixed with H2S 2) SILARC method. Advantages of this method: a) Gas cooling is helpful to split and shrink boron isotopes absorption bands. In order to achieve better selectivity BCl3 gas has to be substantially rarefied (~0.01%-5%) in mixture with carrier gas. b) Laser intensity is lower than in the first method. Some preliminary calculations of dissociation and recombination with carrier gas molecules energetics for both methods will be demonstrated Boron separation in SILARC method can be represented as multistage process: 1) Mixture of BCl3 with carrier gas is putted in reservoir 2) Gas overcooling due to expansion through Laval nozzle 3) IR multiphoton absorption by gas irradiated by specifically tuned laser field with subsequent gradual gas condensation in outlet chamber It is planned to develop software which includes these stages. This software will rely on the following available software based on quantum molecular dynamics in external quantized field: 1) WavePacket: Each particle is treated semiclassicaly based on Wigner transform method 2) Turbomole: It is based on local density methods like density of functional methods (DFT) and its improvement- coupled clusters approach (CC) to take into account quantum correlation. These models will be used to extract information concerning kinetic coefficients, and their dependence on applied external field. Information on radiative corrections to equation of state induced by laser field which take into account possible phase transition (or crossover?) can be also revealed. This mixed phase equation of state with quantum corrections will be further used in hydrodynamical simulations. Moreover results of these hydrodynamical simulations can be compared with results of CFD calculations. The first reasonable question to ask before starting the CFD simulations is whether turbulent effects are significant or not, and how to model turbulence? The questions of laser beam parameters and outlet chamber geometry which are most optimal to make all gas volume irradiated is also discussed. Relationship between enrichment factor and stagnation pressure and temperature based on experimental data is also reported.

• 한국수학교육학회지시리즈C:초등수학교육
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• 제16권3호
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• pp.251-266
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• 2013

본 연구에서는 사칙연산의 1차적 개념을 학습한 초등학생들을 대상으로 거듭제곱과 혼합계산을 내용으로 하였을 때, 정확한 개념의 인지와 개념의 연결로 스키마와 변형된 스키마를 어떻게 구성을 하는지 알아보았다. 즉 사칙연산의 1차적 개념으로 어떠한 스키마와 변형된 스키마를 형성하여 2차적 개념에 대한 관계적 이해를 하는지, 그리고 연구대상자들이 스스로 형성한 스키마와 변형된 스키마를 어떻게 이용하여 문제 해결에 접근을 하는지, 또한 연구대상자들의 개념구성과 문제해결력에서의 스키마는 어떻게 변형을 이루어 나가는지를 심도 있게 조사하였다. 그 결과 1차적 개념에서 2차적 개념으로 발전 할 때, 정확한 1차적 개념에 대한 인지와 스키마 그리고 변형된 스키마가 중요한 요인으로 작용 한다는 것을 알 수 있었고 이때, 1차적 개념끼리의 연결과 정확한 1차적 개념에 대한 인지로 인해서 만들어지는 스키마와 변형된 스키마의 형성이 2차적 개념으로의 발전과 수학적 문제 해결에 무엇보다도 중요한 역할을 한다는 것을 알 수 있었다.