• 대한화학회지
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• 제27권5호
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• pp.320-329
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• 1983

$\alpha$-아미노알킬라디칼들에 대한 안정화에너지를 검토하기 위하여 반경험적 분자궤도함수계산법인 MINDO/3-RHF 방법을 이용하여 고찰하고 비경험적 방법인 ab initio 및 실험적인 연구결과들과 비교하였다. 결과로써 라디칼들의 안정화에너지는 ab initio결과와 일치하게 나타났으며 실험결과와는 상반되게 나타났다. 그리고 라디칼들의 구조도 구조연구를 위해 더 적합하다고 알려진 ab initio 결과와 다르게 나타났다. 그러나 여러가지 증거에 의해 안정화에너지에 관한한 실험과 이론관의 상반된 결과를 일으키는 2가지 요인즉 (1) 실험결과 처리에서의 오차 (2)이온에서의 correlation을 고려하지 않았다는 점 가운데 후자가 더 크게 작용한다는 것을 알 수 있었으며 정성적으로 correlation을 고려했을 때는 실험과 일치하는 경향을 얻었다. 결국 correlation을 고려한 방법을 썼을 경우 실험과 일치하는 경향성을 보일 것으로 예측되었다.

• 태양에너지
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• 제11권1호
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• pp.27-40
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• 1991

에너지 소비 구조의 개선을 목적으로 한 자연에너지 이용시스템의 도입이 전력 계통의 계획 운용에 미치는 영향을 다목적 최적화 방법을 이용하여 평가하는 방법이 논하여 지고 있다. 본 연구에서는 시험 제작한 태양열과 풍력 에너지를 주체로하는 자연에너지 복합 이용시스템이 특정 지역에 복수 도입되어 지는 경우 전력 통계 운용에 의한 경제성, 안정성, 환경에 대한 영향 평가 방법을 검토하였다. 연구 방법은 대상 지역의 일사 분포와 풍속 분포에 의해서 취득 가능한 에너지를 산정하여 전력 계통 부하의 형상에 미치는 영향을 구하였고, 다음에는 대상 기간에 의한 최적 발전 배분을 결정하여 경제성, 안정성, 환경 지표 등의 평가를 하였다. 지금까지는 자연에너지 이용시스템의 도입에 대하여 경제적 측면만 논의되었지만, 본 연구에서 제한된 방법에 의해 안정성과 환경 보전의 영향을 고려한 평가 방법도 가능하다는 것을 나타내었다.

• Nuclear Engineering and Technology
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• 제55권3호
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• pp.884-894
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• 2023

Design and safety assessment of fuel pins for application in innovative Generation IV fast reactors calls for a dedicated nuclear fuel modelling and for the extension of the fuel performance code capabilities to the envisaged materials and irradiation conditions. In the INSPYRE Project, comprehensive and physics-based models for the thermal-mechanical properties of U-Pu mixed-oxide (MOX) fuels and for fission gas behaviour were developed and implemented in the European fuel performance codes GERMINAL, MACROS and TRANSURANUS. As a follow-up to the assessment of the reference code versions ("pre-INSPYRE", NET 53 (2021) 3367-3378), this work presents the integral validation and benchmark of the code versions extended in INSPYRE ("post-INSPYRE") against two pins from the SUPERFACT-1 fast reactor irradiation experiment. The post-INSPYRE simulation results are compared to the available integral and local data from post-irradiation examinations, and benchmarked on the evolution during irradiation of quantities of engineering interest (e.g., fuel central temperature, fission gas release). The comparison with the pre-INSPYRE results is reported to evaluate the impact of the novel models on the predicted pin performance. The outcome represents a step forward towards the description of fuel behaviour in fast reactor irradiation conditions, and allows the identification of the main remaining gaps.

• Journal of Photoscience
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• 제2권2호
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• pp.89-93
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• 1995

Solvatochromic effects and hydrogen bonding interactions of 4-hydroxy-4'-nitrostilbene(NSOH) were investigated. Electronic transition energies of NSOH have good correlation with Taft's $\pi$$^*$. The hydrogen bonding interactions can be accounted by analysis with equation of $\Delta$E= $\Delta$E$_0$ + s($\pi$$^*$ + d$\delta$) + a$\alpha$ + b$\beta$. From UV-visible absorption maximum energies, $\Delta$E = 81.2 kcal/mole - 6.66($\pi$$^*$ - 0.20$\delta$) - 0.66$\alpha$ - 1.93$\beta$ (corr.=0.970) was obtained, and from fluorescence intensity maximum energies, $\Delta$E= 70.07 kcal/mole - 21.6($\pi$$^*$ - 0.11d) - 1.74$\alpha$ - 2.73$\beta$ (corr.=0.947) was obtained. The micropolarity estimated at the solubilization sites is close to the polarity of water. The apparent Taft's $\pi$$^*$ values of solubilization sites are close to 1. Howcver, the solubilization sites for the fluorescent NSOH is rather nonpolar. Both NSOH and NSO$^-$ can be solubilized in CTAB and CTAC micelles and NSOH is the only species that can be solubilized in SDS and Brij-35 micelles.

• Bulletin of the Korean Chemical Society
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• 제24권6호
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• pp.751-756
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• 2003

We have investigated the solvent effects on Δlog $K_s$ (the difference of stability constant of binding) and the relative free energies of binding of $La^{3+} and Nd^{3+}$ ions to 18-crown-6 by a Monte Carlo simulation of statistical perturbation theory (SPT) in diverse solvents. We compared relative binding Gibbs free energies and the differences in stability constant (Δlog $K_s$) of binding of $La^{3+} and Nd^{3+}$ ions to 18-crown-6 in $CH_3OH$ in this study with the experimental. There is a good agreement between our study and the experimental. We noted that Borns function of the solvents, the electron pair donor properties of the solvent, the radii of host and guest and the differences in solvation dominate the differences in the stability constant (Δlog $K_s$) as well as the relative free energies of binding of TEX>$La^{3+} to Nd^{3+}$ ions to 18-crown-6. The results of this study appear promising for providing the association properties of crown ethers with alkaline earth metals among polar solvents and the less polar or non-polar solvents.

• 에너지공학
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• 제14권2호
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• pp.82-97
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• 2005

RPS(Renewable Portfolio Standards)란 전력의 일정 양 또는 비율을 신$\cdot$재생에너지에 의하여 충당하도록 의무화하는 제도로써 정부지원에 의존한 신$\cdot$재생에너지 보급을 시장기능에 의하여 활성화하려는 새로운 정책도구이다. 본 논문은 이와 같은 RPS제도의 국내 도입에 대비하여 RPS의 기본 개념과 시장기구 하의 운용방식, 정책설계 시 고려사항 등을 살펴보았다. 이를 통하여 신$\cdot$재생에너지 전망 및 계획상의 문제점과 RPS도입에 따른 전력시장에서의 효과 등을 확인하고, 최종적으로는 향후 RPS도입을 위한 정책제언을 도출한다.

• 동력기계공학회지
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• 제10권3호
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• pp.45-50
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• 2006

In this paper, creep tests of Mg-Zn-Mn and Mg-Zn-Mn-Ca alloy casted by mold under the temperature range of 473.00-573.00K, and the stress range of 23.42-87.00Mpa were done with the equipment of automatic controlled temperature and computer for data acquisition. The activation energies were obtained by relationship between creep rate and temperature, and the stress exponents were obtained by relationship between creep rate and stress. From the experiment results, the activation energies of Mg-Zn-Mn and Mg-Zn-Mn-Ca alloy were 149.87kJ/mol, 147.97kJ/mol, respectively, and the stress exponents of those alloy were 5.13, 5.59, respectively, under the temperature of 473.00-493.00K and the stress range of 62.43-78.00Mpa. And the activation energies of those alloy were 134.41kJ/mol, 129.22kJ/mol, respectively, and the stress exponent of those alloy were 3.48, 3.77, respectively, under the temperature of 553-573Mpa and the stress range of 23.42-39.00Mpa. Also the lifes of Mg-Zn-Mn-Ca alloy were higher than those of Mg-Zn-Mn alloy, and the results of SEM showed fracture surfaces under low temperature had smaller dimples than those under high temperature.

• International Journal of Aeronautical and Space Sciences
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• 제17권4호
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• pp.455-466
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• 2016

Chemical-kinetic parameters of the equilibrium constants to evaluate the reverse rate coefficients in the shock layer of a blunt body and the expanding flows are derived for the temperature range from 300 K to 20,000 K. The expanded equilibrium constants for the chemical reactions of the dissociation, ionization, associative ionization, and neutral and charge exchange reactions of the atmospheric species and carbon materials are proposed in the present work. In evaluating the equilibrium constants, the inter-nuclear potential energies of the molecular species are calculated by the analytical potential function of the Hulburt-Hirschfelder model, and the parameters of the analytical model are determined from the semi-classically calculated RKR potentials. The electronic states and energies of the atoms are calculated by the electronic energy grouping model, and the rovibrational states and energies of each electronic states of the molecules are evaluated by the WKB method. The expanded equilibrium constants for 31 types of the reactions are provided for the best curve-fit functions, and the recombination reaction rate coefficients evaluated from the present equilibrium constants are compared with existing measured values.

• 한국초전도학회:학술대회논문집
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• 한국초전도학회 1999년도 High Temperature Superconductivity Vol.IX
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• pp.262-265
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• 1999

We report the activation energies which is calculated by adding a term being neglected usually, and magnetic relaxation effects for the surface barrier. The activation energies U at initial magnetization m (m$_{en}$ and m$_{ex}$) and equilibrium magnetization m$_{eq}$ are nearly similar to those of Burlachkov, but the m dependence of the activation energy U is remarkably different. The relaxation effects, which were determined by the m dependence of the activation energies U, are nonlinear for vortex entry, but linear at the initial stage and nonlinear at m(Int) ${\simeq}$ m$_{eq}$ for vortex exit. During relaxation process, the vortex entry at m = m$_{en}$ is faster than the vortex exit at m = m$_{ex}$ by about factor 90. The vortex exit at m = m$_{eq}$ is faster than one at m = m$_{ex}$ by about factor 1.3

• 대한화학회지
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• 제19권4호
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• pp.218-224
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• 1975

바닥상태에 대한 자기무당착장 상호작용 에너지 이론을 2-치환-아크릴로니트릴과 시클로펜타디엔의 Diels-Alder 반응에 적용하여 반응성과 입체 선택성을 조사하였다. 출발점으로는 $\sigma$전자와 $\pi$전자를 다 고려하는 CNDO/2 MO가 사용되었다. 1차 상호작용 에너지 계산으로 정성적인 반응성이 얻어 졌으며 활성화 에너지 값은 실측치 범위의 것이 계산되었다. 2차 상호작용 에너지 계산으로 얻은 입체 선택성은 치환기에 대하여 모두 endo 선택성을 보여주었다. 비대칭 폐환의 원인을 반응원자의 원잣가 비활성 전자밀도로서 설명하였다.