• 공업화학
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• 제34권2호
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• pp.99-105
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• 2023

Recently, 2D materials greatly impact in the various applications especially in the energy conversion and storage devices. Among the 2D materials, nowadays researchers are showing their propensity towards the MXenes due to their potential structural and physical properties as well as their use in various applications. Recently, MXenes have been used as filler in polymer electrolytes membranes and as catalytic support to increase the performance of fuel cells (FCs). But this review covers only recent progress and application of MXenes in proton and anion exchange membranes for FCs. Also, this review will provide a significant guidance and broad overview for future research in MXenes based polymer electrolyte membrane for FCs.

• 한국식품저장유통학회지
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• 제11권4호
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• pp.431-436
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• 2004

건고추의 위생화 및 검역처리와 관련하여 감마선 조사(5, 10 kGy)와 훈증처리(MeBr, $PH_3$)된 건고추의 지장 중 기계적 색도(Hunter L, a, b, ${\Delta}E$) 및 관능적 품질을 평가하였다. 건고추의 가공형태에 따른 비교에서 통고추는 실온저장 중 높은 명도(L) 값을, 분말 고추는 높은 적색도(a) 값을 유지하였다. 건고추 부위별 시료의 색도에 대한 감마선과 훈증 처리의 영향에서 처리 직후에는 전반적인 색차(${\Delta}E$) 값이 크지 않았으나, 저장 8개월 후 통고추는 $PH_3$ 훈증군이, 분말 고추는 5 kGy 조사군이 각각 높은 적색도를 보였다(p<0.05). 감마선 조사 건고추 과피의 적색도는 저장 8개월에 크게 감소하였으며, 훈증 처리된 시료에서도 유사한 변화를 보였다. 건고추 씨의 황색도(b)는 10 kGy 조사군이 가장 낮은 값을 보였으며(p<0.05), 저장 기간이 경과됨에 따라 처리군 간에 유의적인 차이가 나타나지 않았다. 통고추 및 분말고추의 관능적 품질은 상업적 조건의 감마선 및 훈증 처리에 의해 거의 변화되지 않았으며, 저장기간이 경과할수록 대조군에 비해 높은 관능평점을 보여주었다. 이 같은 결과는 감마선 및 훈증 처리 시 통고추 형태보다는 분말고추에서 보다 양호하게 나타났다.

• Bulletin of the Korean Chemical Society
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• 제32권12호
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• pp.4205-4209
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• 2011

The $Li_2Mn_{0.5}Fe_{0.5}SiO_4$ silicate was prepared by blending of $Li_2MnSiO_4$ and $Li_2FeSiO_4$ precursors with same molar ratio. The one of the silicates of $Li_2FeSiO_4$ is known as high capacitive up to ~330 mAh/g due to 2 mole electron exchange, and the other of $Li_2FeSiO_4$ has identical structure with $Li_2MnSiO_4$ and shows stable cycle with less capacity of ~170 mAh/g. The major drawback of silicate family is low electronic conductivity (3 orders of magnitude lower than $LiFePO_4$). To overcome this disadvantage, carbon composite of the silicate compound was prepared by sucrose mixing with silicate precursors and heat-treated in reducing atmosphere. The crystal structure and physical morphology of $Li_2Mn_{0.5}Fe_{0.5}SiO_4$ was investigated by X-ray diffraction, scanning electron microscopy, and high resolution transmission electron microscopy. The $Li_2Mn_{0.5}Fe_{0.5}SiO_4$/C nanocomposite has a maximum discharge capacity of 200 mAh/g, and 63% of its discharge capacity is retained after the tenth cycles. We have realized that more than 1 mole of electrons are exchanged in $Li_2Mn_{0.5}Fe_{0.5}SiO_4$. We have observed that $Li_2Mn_{0.5}Fe_{0.5}SiO_4$ is unstable structure upon first delithiation with structural collapse. High temperature cell performance result shows high capacity of discharge capacity (244 mAh/g) but it had poor capacity retention (50%) due to the accelerated structural degradation and related reaction.

• Nuclear Engineering and Technology
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• 제49권3호
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• pp.549-555
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• 2017

A lead slowing-down spectrometer (LSDS) system is under development to analyze isotopic fissile content that is applicable to spent fuel and recycled material. The source neutron mechanism for efficient and effective generation was also determined. The source neutron interacts with a lead medium and produces continuous neutron energy, and this energy generates dominant fission at each fissile, below the unresolved resonance region. From the relationship between the induced fissile fission and the fast fission neutron detection, a mathematical assay model for an isotopic fissile material was set up. The assay model can be expanded for all fissile materials. The correction factor for self-shielding was defined in the fuel assay area. The corrected fission signature provides well-defined fission properties with an increase in the fissile content. The assay procedure was also established. The assay energy range is very important to take into account the prominent fission structure of each fissile material. Fission detection occurred according to the change of the Pu239 weight percent (wt%), but the content of U235 and Pu241 was fixed at 1 wt%. The assay result was obtained with 2~3% uncertainty for Pu239, depending on the amount of Pu239 in the fuel. The results show that LSDS is a very powerful technique to assay the isotopic fissile content in spent fuel and recycled materials for the reuse of fissile materials. Additionally, a LSDS is applicable during the optimum design of spent fuel storage facilities and their management. The isotopic fissile content assay will increase the transparency and credibility of spent fuel storage.

• 전기화학회지
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• 제24권4호
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• pp.93-99
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• 2021

스트레처블 에너지 저장 장치 경량화를 위해 금속 집전체를 대체할 경량 물질 개발에 대한 관심이 높아지고 있다. 본 연구에서는 전도성 고분자인 PEDOT:PSS를 전기방사법으로 제조한 나노 섬유를 리튬이온전지용 집전체로 사용하였다. 나노 섬유는 도펀트인 DMSO를 사용해 향상된 전기 전도성을 나타냈으며, 신축성 평가결과로 부터 30% 이상의 신축률을 보여주었다. 또한, 나노 섬유 집전체를 사용함으로써 액체 전해질의 침투가 용이하며, 나노 섬유 네트워크를 통해 전자전도성을 높이는 효과를 나타났었다. DMSO 도핑 PEDOT:PSS@PAM 나노 섬유 필름 집전체를 사용한 리튬이온전지는 135mAh g^-1의 높은 방전용량을 보여주었으며, 1000 사이클 이후 73.5%의 높은 용량 유지율을 나타내었다. 따라서, 전도성 나노 섬유의 우수한 전기화학적 안정성과 기계적 특성은 신축성 에너지 저장 장치의 경량 집전체로서의 활용이 가능함을 보여주었다.

• 한국전기전자재료학회논문지
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• 제23권11호
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• pp.843-847
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• 2010

This paper in concerned with the electrochemical properties for supercapacitor of composition with variation of super P/MWCNTs(multi-walled carbon nanotubes) contents. Electrochemical properties of the super P/MWCNTs were measured by cyclic voltammetry at the scan rates of 0.5 mV/s is $TEABF_4$(tetra-ethyl-ammonium-tetra-fluoro-borate) as electrolytes. As a result, the composition for 6 wt% content of MWCNTs led to an increase of capacitance, but DC resistance were decreased. It was found that the content and dispersion appearance of MWCNTs was attributed to the increase in capacitance and lower DC resistance.

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.256-256
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• 2006

The design and synthesis of novel biomolecular materials, based on mimicking the properties of molecules found in nature, is providing materials with unusual properties. Resilin serves as an energy storage material in insects and facilitates flight, jumping (in fleas, froghoppers etc) and sound production (cicadas, etc). Resilin is initially produced as a soluble protein and in its mature form is crosslinked through formation of dityrosine units into a very large insoluble polymer. In the present study, we have synthesized a recombinant form of resilin that can be photochemically cross-linked into a resilient, rubber-like biomaterial that may be suitable for spinal disc implants. This material is almost perfectly elastic and its fatigue lifetime in insects must be >500 million cycles.

• Journal of Industrial and Engineering Chemistry
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• 제68권
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• pp.129-139
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• 2018

The effects of N doping concentration and dopant moieties on the electrochemical properties of nanoporous graphene and their dependence on annealing temperature are investigated. Four types of N moieties - amide, amine, graphitic-N, and oxidized-N - are obtained, which transformed into pyridinic-N and pyrrolic-N upon annealing. The diffusion coefficient (D') of the ions in the electrode is the maximum at $400^{\circ}C$ because of a high level of N doping, whereas the second highest D0 value is obtained at $700^{\circ}C$ owing to a high level of reduction and N doping. The highest specific capacitance is obtained for the sample annealed at $400^{\circ}C$.

• Transactions on Electrical and Electronic Materials
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• 제15권5호
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• pp.265-269
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• 2014

Carbon nanofiber electrode has been fabricated for energy storage systems by the electrospinning of SU-8 precursor and subsequent pyrolysis. Various parameters including the applied voltage, the distance between syringe tip and target collector and the flow rate of the polymer affect the diameter of SU-8 electrospun nanofibers. Shrinkage during pyrolysis decreases the fiber diameter. As the pyrolysis temperature increases, the resistivity decreases dramatically. Low resistivity is one of the important characteristics of the electrodes of an energy storage device. Given the advantages of carbon nanofibers having high external surface area, electrical conductivity, and lithium intercalation ability, SU-8 derived carbon nanofibers were applied to the anode of a full lithium ion cell. In this paper, we studied the physical properties of carbon fiber electrode by scanning transmission microscopy, thermal gravimetric analysis, and four-point probe. The electrochemical characteristics of the electrode were investigated by cyclic voltammogram and electrochemical impedance spectroscopy plots.

• 한국수소및신에너지학회논문집
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• 제18권4호
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• pp.399-405
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• 2007

The hyper-eutectic Mg-33.5%Ni alloy was rapidly solidified by melt spinning process. The melt-spun Mg-33.5%Ni has amorphous structure and crystallization occurred above $162^{\circ}C$. The hydriding and dehydriding rates of melt-spun Mg-33.5%Ni increased with cycle and high rate of hydrogen storage occurred at 3rd cycle. The maximum hydrogen amount absorbed in melt-spun Mg-33.5%Ni at $300^{\circ}C$ is about 4.5%.