• Title/Summary/Keyword: co-evolution

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Electrochemical Characterization of Electrospun LaCoO3 Perovskite Nanofibers Prepared at Different Temperature for Oxygen Reduction and Evolution in Alkaline Solution (다양한 온도에서 합성한 전기방사 LaCoO3 페롭스카이트 나노섬유의 알칼리용액에서 산소환원 및 발생반응에 대한 전기화학 특성)

  • Lopez, Kareen J.;Sun, Ho-Jung;Park, Gyungse;Eom, Seungwook;Shim, Joongpyo
    • Transactions of the Korean hydrogen and new energy society
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    • v.26 no.2
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    • pp.148-155
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    • 2015
  • Electrospun $LaCoO_3$ perovskite nanofibers were produced for the air electrode in Zn-air rechargeable batteries using electrospinning technique with sequential calcination. The final calcination temperature was varied from 500 to $800^{\circ}C$ in order to determine its effect on the physical and electrochemical properties of the prepared $LaCoO_3$ perovskite nanofibers. The surface area of the electrospun $LaCoO_3$ perovskite nanofibers were observed to decrease with increasing final calcination temperature. Electrospun $LaCoO_3$ perovskite nanofibers calcined with final calcination temperature of $700^{\circ}C$ had the best electrocatalytic activity among the prepared perovskite nanofibers.

Soil Carbon Dioxide Flux and Organic Carbon in Grassland after Manure and Ammonium Nitrate Application

  • Lee, Do-Kyoung;Doolittle, James J.
    • Korean Journal of Environmental Agriculture
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    • v.24 no.3
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    • pp.238-244
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    • 2005
  • Fertilization effects on changes in soil $CO_2$ flux and organic C in switchgrass (Panicum virgatum L.) land managed for biomass production were investigated. The mean daily soil $CO_2$ flux in the manure treatment was 5.63 g $CO_2-C\;m^{-2}\;d^{-1}$, and this was significantly higher than the mean value of 3.36 g $CO_2-C\;m^{-2}\;d^{-1}$ in the control. The mean daily $CO_2$ fluxes in N and P fertilizer treatments plots were not different when compared to the value in the control plots. Potentially mineralizable C (PMC), soil microbial biomass C (SMBC), and particulate organic C (POC) were highest at the 0 to 10 cm depth of the manure treatment. Potentially mineralizable C had the strongest correlation with SMBC (r = 0.91) and POC (r = 0.84). There was also a strong correlation between SMBC and POC (r = 0.90). Our results indicated that for the N and P levels studied, fertilization had no impact on temporal changes in soil organic C, but manure application had a significant impact on temporal changes in soil $CO_2$ evolution and active C constituents such as PMC, SMBC, and POC.

A Study on the storage of Fresh Fruits and Vegetables (Part II) Effects of Intercellular atmosphere and Ethylene evolution by control of external pressure and gas composition in Apple Fruits. (청과물 저장에 관한 연구(제 2보) -사과 저장에 있어서 환경압력 및 기체조성이 사과조직내 기체조성과 Ethylene 생성에 미치는 영향-)

  • 손태화;최종욱;서온수
    • Microbiology and Biotechnology Letters
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    • v.1 no.1
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    • pp.25-30
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    • 1973
  • Experiments were carried out to clarify changes of intercellular gas composition, respiration and ethylene evolution by controlled external atmospheric pressure and external gas composition on apples. Jonathan apples, harvested 25, in September and Rolls apples, harvested 25, in October, 1971 and 1972 were used. Results obtained were as follows: 1. Intercellular gas volumes were proportionally changed by the given pressure, and the given pressure remarkably affected internal gas composition and volume of apples. As intercellular gas volumes were reached in their equilibrium within 5 min. after treatment, the internal atmospheric conditions became constant rapidly. 2. The increase of internal $CO_2$ production was co-related with an amount of internal $O_2$ consumption, therefore, the decreasing period of internal $O_2$ consumption was equalled to the period of climacteric rise in respiration. 3. The increasing of $CO_2$ production followed evolution of $C_2$H$_4$ and this phenomenon on SAP part. was subsequent to NAP part 4. In sub-atmospheric storage, CA effect was also obtained by control of low $O_2$ and high $CO_2$ concentration.

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Biological Network Evolution Hypothesis Applied to Protein Structural Interactome

  • Bolser, Dan M.;Park, Jong Hwa
    • Genomics & Informatics
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    • v.1 no.1
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    • pp.7-19
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    • 2003
  • The latest measure of the relative evolutionary age of protein structure families was applied (based on taxonomic diversity) using the protein structural interactome map (PSIMAP). It confirms that, in general, protein domains, which are hubs in this interaction network, are older than protein domains with fewer interaction partners. We apply a hypothesis of 'biological network evolution' to explain the positive correlation between interaction and age. It agrees to the previous suggestions that proteins have acquired an increasing number of interaction partners over time via the stepwise addition of new interactions. This hypothesis is shown to be consistent with the scale-free interaction network topologies proposed by other groups. Closely co-evolved structural interaction and the dynamics of network evolution are used to explain the highly conserved core of protein interaction pathways, which exist across all divisions of life.

Macro-environmental Drivers and Technological Evolution of Complex Product System: Evidence from Nuclear Power Plant (거시환경요인과 복합제품시스템의 기술진화: 원자력 발전 플랜트의 사례를 중심으로)

  • Kwak, Kiho;Kim, Wonjoon;Kim, Minki;Cho, Chang Yeon
    • Journal of Technology Innovation
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    • v.25 no.2
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    • pp.89-125
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    • 2017
  • Complex product systems (CoPs) is a engineering-intensive products with high-ended design technology, which are closely linked with national economic growth and development of social infrastructures. Accordingly, in order to understand the technological evolution of CoPs, it is necessary to identify the macro-environmental drivers surrounding the CoPs and their impact on the technological evolution of the CoPS. Therefore, we investigate the effect of policy, economic and social drivers on the technological evolution of CoPS by implementing the longitudinal case study on nuclear power plant during the periods between 1950 and 2010s. Based on the analysis of various sources of secondary data and primary data through interviews, we found that the technological evolution of nuclear power plant is progressed as "Phase 1: Application research for peaceful utilization of nuclear energy" between 1950s and 1960s, "Phase 2: The first renaissance of nuclear energy" during 1970s, "Phase 3: Enhancement of safety and the catch-up of latecomers in nuclear energy" between 1990s and 2000s, and "Phase 4: Top prioritization of safety and the development of next generation reactors for the second renaissance of nuclear energy" since 2010s. We also found that various kinds of policy, economic and social drivers, such as energy policy, investment in technology development, economic growth and energy demand, social acceptability and environmental concern, have affected the technology evolution of nuclear power plant at each phase. We emphasize the role of macroenvironmental drivers in the technological evolution of CoPS. We also suggest that countries that endeavor to develop CoPs need to utilize those drivers for enhancing competitiveness and sustaining leadership.

Synthesis of Co3O4 Nanocubes as an Efficient Electrocatalysts for the Oxygen Evolution Reacitons (물 분해 과정에서 효율적인 촉매 특성을 보이는 Co3O4 nanocubes 합성)

  • Choi, Hyung Wook;Jeong, Dong In;Wu, Shengyuan;Kumar, Mohit;Kang, Bong Kyun;Yang, Woo Seok;Yoon, Dae Ho
    • Composites Research
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    • v.32 no.6
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    • pp.355-359
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    • 2019
  • The high efficient water splitting system should involve the reduction of high overpotential value, which was enhanced by the electrocatalytic reaction efficiency of catalysts, during the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) reaction, respectively. Among them, transition metal-based compounds (oxides, sulfides, phosphides, and nitrides) are attracting attention as catalyst materials to replace noble metals that are currently commercially available. Herein, we synthesized optimal monodisperse Co3[Co(CN)6]2 PBAs by FESEM, and confirmed crystallinity by XRD and FT-IR, and thermal behavior of PBAs via TG-DTA. Also, we synthesized monodispersed Co3O4 nanocubes by calcination of Co3[Co(CN)6]2 PBAs, confirmed the crystallinity by XRD, and proceeded OER measurement. Finally, the synthesized Co3O4 nanocubes showed a low overpotential of 312 mV at a current density of 10 mA·cm-2 with a low Tafel plot (96.6 mV·dec-1).

Analysis of the Research on Augmented Reality Using Knowledge Domain Visualization based on Co-Citation Analysis (동시인용분석 기반 지식영역 가시화 기법을 활용한 증강현실 연구 분석)

  • Lee, Jeonghwan;Lee, Jae Yeol
    • Korean Journal of Computational Design and Engineering
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    • v.18 no.5
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    • pp.309-320
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    • 2013
  • Augmented reality (AR) is considered to be an excellent user interface to a 3D information space embedded within physical reality. For this reason, it has been applied to various applications such as design, medical service, interaction, and collaboration. However, there is no formal way of analyzing the research trend and evolution of augmented reality. This paper identifies the research trend and change in augmented reality (AR) via co-citation analysis. The co-citation analysis provides how the AR research has evolved, who are main contributors, and which papers suggest essential and influencing impact. To systematically analyze the cocitation, we have retrieved 1,145 papers from the Web of Science and applied a scientomertric analysis using CiteSpace. Based on the co-citation analysis of authors and documents, it is possible to analyze the evolution of augmented reality, key authors and papers, and breakthroughs. We have also compared the proposed approach with survey papers written by experts so that the result of the co-citation analysis can compromise the qualitative result done by experts, and thus it can provide a different view and insight for visualizing the research on augmented reality.