• BMB Reports
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• 제37권5호
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• pp.533-537
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• 2004

Previously published kinetic data on the interactions of seventeen different enzymes with their physiological substrates are re-examined in order to understand the connection between ground state binding energy and transition state stabilization of the enzyme-catalyzed reactions. When the substrate ground state binding energies are normalized by the substrate molar volumes, binding of the substrate to the enzyme active site may be thought of as an energy concentration interaction; that is, binding of the substrate ground state brings in a certain concentration of energy. When kinetic data of the enzyme/substrate interactions are analyzed from this point of view, the following relationships are discovered: 1) smaller substrates possess more binding energy concentrations than do larger substrates with the effect dropping off exponentially, 2) larger enzymes (relative to substrate size) bind both the ground and transition states more tightly than smaller enzymes, and 3) high substrate ground state binding energy concentration is associated with greater reaction transition state stabilization. It is proposed that these observations are inconsistent with the conventional (Haldane) view of enzyme catalysis and are better reconciled with the shifting specificity model for enzyme catalysis.

• Bulletin of the Korean Chemical Society
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• 제14권6호
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• pp.692-696
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• 1993

Prediction of retention times in transition metal-mandelate and transition metal-tartrate complex systems were studied on the cation exchanger. Plots of k' vs [mandelate] and k' vs [tartrate] were obtained under the condition of a constant competing cation concentration. The equation to predict the retention time of transition metal ion was derived from the ion exchange equilibria. Individual capacity factors (${k_1}',\;{k_2}'$) and stability constants ($K_1,\;K_2$) of the complexes were calculated from the non-linear least square method. Good resolution of the transition metals was predicted by the stepwise equation in the gradient method. The values of retention times from the calculation and the experiment agreed well each other.

• 한국통신학회논문지
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• 제37A권12호
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• pp.1085-1092
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• 2012

이동통신 시스템은 무선 자원과 배터리 전력을 효율적으로 관리하기 위해 사용자 상태 천이 방식을 정의하고 있다. 이러한 상태 천이 방식에서는 에너지 소비가 많은 상태가 기본적으로 짧은 접속 지연을 제공하므로 에너지와 지연 성능 사이에 트레이드오프 관계가 존재한다. 본 논문에서는 이동 응용 서비스의 트래픽 속성을 고려하여 UMTS 시스템의 사용자 상태 천이 방식을 분석한다. 상태 천이 방식의 마르코프 모델링을 통하여 에너지 소비량과 활성 지연을 수학적으로 도출하고 운용 파라미터에 따라 이들의 트레이드오프 관계를 파악한다. 분석 결과로 도출된 에너지-지연 트레이드오프 곡선은 주어진 상태 천이 방식이 달성 가능한 성능 한계를 보여주며 지연 요구사항을 보장하면서 에너지 소비를 최소화하는 최적 운용 전략을 제시한다.

• Journal of the Korean Physical Society
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• 제73권11호
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• pp.1729-1734
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• 2018

Organic-inorganic halide perovskite single crystals undergo phase transition of being cubic, tetragonal, or orthorhombic depending on the temperature. We investigated the $CH_3NH_3PbBr_{3-x}I_x$ single crystals grown by the inverse temperature crystallization method with temperature-dependent UV-Vis absorption and photoluminescence. From the temperature-dependent absorption measurement, the optical band gap is extracted by derivation of absorption spectrum fitting and Tauc plot. In our results, $CH_3NH_3PbBr_{3-x}I_x$ single crystals show that an abrupt change in optical band gap, PL peak position and intensity appears around 120 K - 170 K regions, indicating the phase transition temperature.

• Nuclear Engineering and Technology
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• 제56권4호
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• pp.1267-1276
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• 2024

The emerging technologies at the industrial level have deployed rapidly within the energy transition process innovations. The nuclear industry incorporates several technologies like Artificial Intelligence (AI), Machine Learning (ML), Digital Twins, High-Performance-Computing (HPC) and Quantum Computing (QC), among others. Factors identifications are explained to set up a regulatory framework in the digitalization era, providing new capabilities paths for nuclear technologies in the forthcoming years. The Analytical Network Process (ANP) integrates the quantitative-qualitative decision-making analysis to assess the implementation of different aspects in the digital transformation for the New-Energy Transition Era (NETE) with a Nuclear Power Infrastructure Development (NPID).

• 한국수소및신에너지학회논문집
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• 제28권1호
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• pp.85-91
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• 2017

To develop a pressurized chemical looping combustor, effect of pressure on minimum fluidization velocity and transition velocity to fast fluidization was investigated in a two-interconnected pressurized fluidized bed system using oxygen carrier particle. The minimum fluidization velocity was measured by bed pressure drop measurement with variation of gas velocity. The measured minimum fluidization velocity decreased as the pressure increased. The transition velocity to fast fluidization was measured by emptying time method and decreased as the pressure increased. Gas velocity in the fuel reactor should be greater than the minimum fluidization velocity and gas velocity in the air reactor should be greater than the transition velocity to fast fluidization to ensure proper operation of two interconnected fluidized bed system.

• Bulletin of the Korean Chemical Society
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• 제34권11호
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• pp.3425-3428
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• 2013

We solve the Klein-Gordon equation with the Morse empirical potential energy model. The bound state energy equation has been obtained in terms of the supersymmetric shape invariance approach. The relativistic vibrational transition frequencies for the $X^1{\sum}^+$ state of ScI molecule have been computed by using the Morse potential model. The calculated relativistic vibrational transition frequencies are in good agreement with the experimental RKR values.

• 기술혁신학회지
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• 제17권2호
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• pp.355-379
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• 2014

새로운 에너지 기술이 기존 사회시스템과 공존하며 확산되는 과정은 저탄소 사회로의 전환을 위해 꼭 필요하지만 어려운 여정이다. 정부주도로 추진되고 있는 서남해 2.5GW 해상풍력사업은 대용량 신재생에너지발전을 중앙전력계통으로 연계하는 것을 목표로 추진되고 있다. 따라서 성공적인 해상풍력 발전의 도입을 위해서는 기존 사회기술시스템의 전환도 병행되어야 한다. 본 연구는 다층적 관점과 전략적 니치관리를 방법론으로 해상풍력기술의 니치전략 적용에 대한 에너지 시스템 전환을 분석한다. 연구결과로서 새로운 기술이 기존 레짐(regime) - 환경상황(landscape)과 연계, 소통을 거쳐 성장하는 과정을 다층적으로 분석하고 에너지체제와 신기술의 관계의 변화를 구조화 하였다. 또한 전략적 니치관리 연구를 적용하여 니치실험 착수단계에서 내재하는 장애요인을 진단하고 해상풍력 실증사업 지연의 원인을 파악하였다. 이를 통해 해상풍력 니치기술이 에너지체제와 다양한 제도 속에서 안정적으로 성장할 수 있다는 실천적 시사점을 도출하였다.

• Bulletin of the Korean Chemical Society
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• 제31권11호
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• pp.3183-3189
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• 2010

In order to increase the specific capacitance and energy density of supercapacitors, non-aqueous supercapacitors were prepared using lithium transition-metal oxides and activated carbons as active materials. The electrochemical properties were analyzed in terms of the content of lithium transition-metal oxides. The results of cyclic voltammetry and AC-impedance analyses showed that the pseudocapacitance may stem from the synergistic contributions of capacitive and faradic effects; the former is due to the electric double layer which is prepared in the interface of activated carbon and organic electrolyte, and the latter is due to the intercalation of lithium ($Li^+$) ions. The specific capacitance and energy density of a supercapacitor improved as the lithium transition-metal oxides content increased, showing 60% increase compared to those of supercapacitor using a pure activated carbon positive electrode.

• 무역학회지
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• 제45권5호
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• pp.55-74
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• 2020

This study examines the policy direction and specific countermeasures for addressing possible port labour issues from the perspective of Just Transition which may be raised by closing coal fired power plants in Korea. Current energy transition policy and port labour policy in Korea are reviewed and case studies in the countries which has experienced closure of coal fired power plants are undertaken. Although it varies from country to country, a similar approach was found that the employment problem of coal fired power plant closures and measures based on Just Transition regime to mitigate the negative impacts that occur in the region are the key to successful transition. It is suggested that countermeasures for port labour should be institutionalized for providing stakeholders with legal stability covering labours not only directly employed by the plants but also employed in entities in the whole supply chains.