• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2005년도 춘계학술발표회
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• pp.471-472
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• 2005

After thermal aging treatment at 693 K for 322 hours, any discernable precipitation could not be found in the $13{\sim}22$ Cr ODS steels, but showing an increase in SP-DBTT and reduction in upper shelf energy. The degree of aging embrittlement increases with Cr content such that the increases in SP-DBTT are 10, 50 and 73 K in 13, 16 and 19 Cr ODS steel, respectively. Amount of hardening also increased linearly as a function of Cr content. Based on the TEM observation, the origin of hardening must be related to the invisibly fine size of Cr-rich ${\acute{\alpha}}-phase$ (<1 nm).

• Journal of Mechanical Science and Technology
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• 제15권1호
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• pp.35-43
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• 2001

Both tensile and tear properties of short-fiber reinforced Chloroprene rubber have been studied as functions of the fiber aspect ratio and fiber content. Both properties increased when both the fiber aspect ratio and fiber content were increased. The fiber reinforced rubbers exhibited maximum values of these properties at a fiber aspect ratio of about 300. When the fiber aspect ratio exceeds 400, the mechanical properties decreased with the fiber content because of the non-uniform dispersion of fibers. The tensile modulus was compared with the prediction by the Halpin-Tsai equations for randomly oriented cases. A bonding agent was used in the fiber treating process. It was found that the ultimate tensile strength, torque, tearing energy and tensile modulus of the rubbers with treated fibers were much higher than those with untreated ones.

• Corrosion Science and Technology
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• 제5권3호
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• pp.94-98
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• 2006

The next generation nuclear power reactor will use Pb-Bi as the cooling material. The steel structure materials such as HT-9 used in the reactor suffer from corrosion when they are exposed to high temperature Pb-Bi. Therefore corrosion should be prevented to use Pb-Bi as the coolant material without any safety problem. One method is to control the oxygen content in Pb-Bi. An appropriate amount of oxygen in Pb-Bi can produce a thin oxide layer on steel, and this layer protects the steel from corrosion attack. Since the required oxygen content in Pb-Bi is in the range of $10^{-5}$ to $10^{-7}$ wt%, this small oxygen content can be controlled by flowing a mixture of hydrogen gas and water vapor. The stagnant corrosion test of HT-9 samples was performed by controlling the oxygen content up to 2,000 hours. The corrosion behavior of HT-9 was analyzed at the temperatures of $500^{\circ}C$ and $650^{\circ}C$ with a reduced condition and a oxygen content of $10^{-6}$ wt%.

• Elastomers and Composites
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• 제51권2호
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• pp.93-98
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• 2016

The composites of EVA/EPDM including aluminum trioxide (ATH) as a fire retardant were manufactured for the purpose of improving low temperature property and flame resistance in the rubbery materials. The ratio of EVA to EPDM didn't affect the flame resistance of the rubber composites. The addition of ATH resulted in increase of the flame resistance. In the evaluation of the cold resistance, the increasing EPDM content showed enhancement of cold resistance in the composites due to increasing low Tg EPDM. It was found out that tensile strengths of the composites showed a maximum value at 100 phr of ATH by reinforcing effect, but a minimum value at 200 phr of ATH owing to slippage between the flame retardant by the external stress. In the measurement of solvent resistance in tetrahydrofuran, the increasing ATH content yielded enhancement of solvent resistance by reducing swelling of the composite, and increasing EPDM content also resulted from increase of the solvent resistance by reduction of polarizability as well as increase of crosslink in the composites.

• Horticulture, Environment, and Biotechnology : HEB
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• 제59권6호
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• pp.835-845
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• 2018

We studied the role of ethylene control in regulating energy metabolism, antioxidant enzyme activity, and vase life of cut rose Rosa hybrida 'Carola'. Rose flowers at stage II were sprayed with one of the following solutions: water (control), $10{\mu}L\;L^{-1}$ 1-methylcyclopropene (1-MCP), or $0.5g\;L^{-1}$ 2-chloroethanephosphonic acid (ethephon). After harvest, ethylene production rate, respiration intensity, energy charge (EC), activities of energy metabolism-related and antioxidant enzymes, and malondialdehyde (MDA) content were measured. Results showed that 1-MCP enhanced the activities of superoxide dismutase, $H^+$-adenosine triphosphatase, $Ca^{2+}$-adenosine triphosphatase, succinic dehydrogenase, and cytochrome c oxidase, increased adenosine triphosphate (ATP) content, maintained high EC levels, inhibited respiration intensity, reduced peroxidase (POD) and polyphenol oxidase (PPO) activity and MDA accumulation, and prolonged vase life. Ethephon promoted ethylene production and respiration intensity, increased POD and PPO activity, reduced ATP content and EC levels, and accelerated senescence. Our results support a novel role for ethylene control in regulating senescence of 'Carola'.

• 한국수소및신에너지학회논문집
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• 제32권1호
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• pp.86-91
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• 2021

In order to save the energy in vehicles using renewable energy, it is necessary to reduce the weight of parts with polymer matrix composites. Carbon nanotube (CNT) is the nano-scale reinforcement used to increase the interlaminar strength of fiber reinforced composites or enhance the fracture toughness of polymer. However, since the degree of improvement in mechanical properties varies according to the various experimental conditions such as shape of reinforcement, types of matrix and dispersion of reinforcement, research to find the optimal conditions is essentially needed. In this study, CNT/epoxy composites with different CNT concentration were fabricated under the same conditions, and the optimal CNT content (2 wt%) was found through Mode 1 fracture toughness test. Furthermore, through optical microscopy, it was confirmed that the fracture toughness was rather decreased due to the CNT aggregation when the CNT content exceeded 2 wt%.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2002년도 춘계공동학술발표회요약집
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• pp.418.1-418
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• 2002

• 한국수소및신에너지학회논문집
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• 제25권5호
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• pp.459-467
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• 2014

The catalytic steam reforming of toluene, a major component of biomass tar, was studied using several catalysts at various temperatures $400-800^{\circ}C$, kind of metal, and metal loading content. Ru and K promoted Ni-base catalyst were prepared, and used for steam reforming of toluene with steam/toluene molar ratio of 25. Concentration of toluene in reactant flow is $30g/Nm^3$ that is usual content of tar from biomass gasifier. The result from experiments showed that $H_2$ content in product gas and toluene conversion increased with temperature. Where in high temperature range, CO and $CO_2$ content in product gas were affected mainly by Boudouard reaction. Ni/Ru-K(3wt%)/$Al_2O_3$ catalyst showed best performance on steam reforming of toluene than used catalysts in this study at whole temperature. Catalysts have been characterized by XRD, TG. XRD analysis displayed that Ni particle size on Ni/Ru-K (3wt%)/$Al_2O_3$ catalyst was 29.4nm. Activation energy of Ni/Ru-K (3wt%)/$Al_2O_3$ catalyst was calculated 36.8kJ/mol by Arrhenius plot.

• 콘크리트학회지
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• 제4권1호
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• pp.81-87
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• 1992

본 논문에서는 강섬유 혼입량과 강섬유 형상비에 대한 강섬유보강콘크리트의 휨 피로거동을 분석하기 위하여 일련의 강섬유보강콘크리트 시험체에 대하여 피로실험을 수행하였다. 피로실험은 3점 휨 실험법으로 실시하였으며, 실험시 각 시험체의 하중반복회수에 대한 중앙처짐과 피로파괴시의 반복회수를 조사하였다. 이들 실험 결과를 토대로 반복회수에 대한 강섬유보강콘크리트의 중앙처짐, 비탄성변형에너지 및 탄성변형형에너지등을 비교 분석하였으며, 강섬유보강콘크리트의 S-N선도를 작도하였다. 연구결과, 강섬유 혼입량이 클수록 영구변형에 손실되는 에너지가 크게 감소하고, 균열 확대에 소모되는 에너지가 증가하였으며, 동일한 강섬유 혼입량을 갖는 강섬유콘크리트의 경우 강섬유 형상비가 클수록 탄성변형에너지는 작았다. 아울러 본 피로실험 결과를 회귀분석하여 구한 S-N선도에 의하면 강섬유 혼입량이 1.0%인 강섬유보강 콘크리트의 반복회수 200만회에 대한 피로초기균열 발생시의 정적강도의 약 70%로 나타났다.

• 방사선산업학회지
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• 제4권1호
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• pp.53-57
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• 2010

Cooking drips which were obtained as by-product after seafood processing in the food industries, still contain lots of proteins, carbohydrates, and other functional materials. But, the seafood cooking drips are easily contaminated because of its rich nutrients, and their color are very dark. This study was conducted to investigate the effect of gamma irradiation on the quality of seafood cooking drips including Hizikia fusiformis, Enteroctopus dofleini, and Thunnus thynnus. The Hunter's color values (L, Brightness) of H. fusiformis, and T. thynnus were increased with increasing irradiation doses, showing becoming bright. The crude protein content and crude lipid content were increased by gamma irradiation. These results indicated that gamma irradiation increased extraction efficiency of available compounds in cooking drips.