• Journal of Radiation Industry
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• v.5 no.2
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• pp.137-143
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• 2011

Epoxy resins are widely used as high performance thermosets in many industrial applications, such as coatings, adhesives and composites. Recently, a lot of research has been carried out in order to improve their mechanical properties and thermal stability in various fields. Carbon nanotubes possess high physical and mechanical properties that are considered to be ideal reinforcing materials in composites. CNT-reinforced epoxy system hold the promise of delivering superior composite materials with their high strength, light weight and multi functional features. Therefore, this study used multi-walled carbon nanotubes (MWNT) and gamma rays to improve the mechanical and thermal properties of epoxy. The diglycidyl ether of bisphenol A (DGEBA) as epoxy resins were cured by gamma ray irradiation with well-dispersed MWNTs as a reinforcing agent and triarylsulfonium hexafluoroantimonate (TASHFA) as an initiator. The flexural modulus was measured by UTM (universal testing machine). At this point, the flexural modulus factor exhibits an upper limit at 0.1 wt% MWNT. The thermal properties had improved by increasing the content of MWNT in the result of TGA (thermogravimetric analysis). However, they were decreased with increasing the radiation dose. The change of glass transition temperature by the radiation dose was characterized by DMA (dynamic mechanical analysis).

• Journal of the Korean Society of Radiology
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• v.15 no.6
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• pp.795-801
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• 2021

The designed drone-based unmanned remote radiation detection module was developed according to the needs of the nuclear power plant decommissioning workshop. Using the Geiger-Mueller tube sensitive to low-level radiation measurement, It was manufactured to measure the amount of radiation leaking into and out of the containment vessel. The drone-based radiation detection module weighs less than 200g, It can be operated inside and outside the containment vessel of a nuclear power plant. To check the performance of the designed equipment, a performance evaluation test was conducted with reference to the international standard (IEC-60864). The stability of the radiation detection module designed to meet the needs of the field the statistical rate of change by repeated measurements in the rate of change experiment to evaluate the measurement accuracy was ±4.6%. The accuracy ±7.3% in the linearity experiment to evaluate the dose rate dependence, the linear The figure satisfies the international performance evaluation standard of ±3.5%. The radiation detection module developed in this study is a customized equipment for a nuclear power plant dismantling workshop. It will be helpful for accurate measurement of space dose rate and safety management of radiation worksites in sites with a lot of radiation dust.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.06a
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• pp.481-483
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• 1998

The problem of production of new materials based on polyheteroarylenes and other polymers combining good mechanical and dielectric properties. radiation and chemical stability with heat- and thermal stability is related with the development of efficient synthesis technique of starting low-molecular compounds. Alicyclic dianhydrides are believed to be the promising monomers to synthesize various polymers.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.6
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• pp.807-815
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• 2004

In order to evaluate the static stability of hybrid carbody structures of Korean Tilting Train eXpress(TTX) caused by degradation of composites under ground environments, T300/AD6005 graphite/epoxy composite specimens were exposed to accelerated environmental conditions including ultraviolet radiation, temperature and moisture fer 2000 hours. It was found that the stiffness and strength of composites after aging were lower than those of unexposed specimens, and decreased as the aging time increases. The values of the degraded properties were used in the static analysis to check the static stability of hybrid carbody structures caused by environmental degradation of composites. The results shown that the structural stability of hybrid carbody structures was affected by the degradation of composites after exposure to accelerated aging environments.

• Applied Biological Chemistry
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• v.19 no.2
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• pp.75-81
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• 1976

High ionic strength is expected to enhance dissociation of Ca-DPA from spores and to contribute to a detrimental effect on spore stability or on spore heat resistance with a combined treatment of gamma-radiation. From this study, this hypothesis has become apparent as as follows; 1) Ca-DPA dissociation contributes to loss of stability of bacterial spores with respect to heat resistance, survival during storage, and 2) the cytoplasmic membrane plays a role in maintaining the stability of DPA-Ca-spore complex, apparently by serving as a permeability barrier.

• Analytical Science and Technology
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• v.24 no.6
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• pp.414-420
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• 2011

In this study, radiation measurement system has been investigated to set up for the radioisotopes analysis in the radioactive waste samples after selecting the radiation counters of alpha beta and gamma nuclides. The counting efficiencies for alpha, beta and gamma measurement systems were calibrated. To obtain stability of the radiation detectors, quality control program has been established. Also, minimum detectable activities (MDAs) depending on the type of samples were calculated for increasing the confidence level for analytical result.

• Bulletin of the Korean Chemical Society
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• v.31 no.4
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• pp.910-914
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• 2010

A novel synthetic route has been developed to prepare $\alpha$-cobalt hydroxide with intercalated nitrate anions. It was successfully synthesized by $\gamma$-ray irradiation under simple conditions, i.e., air atmosphere, without base. Under $\gamma$-ray irradiation, it leads to the formation of layered cobalt hydroxynitrate compounds which have small crystalline size and have the role of a generator of hydroxyl anion. Structural and morphological characterizations were performed by using power X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and high resolution transmission electron microscopy (HR-TEM). The component and thermal stability of the sample were respectively measured by Fourier transform infrared (FT-IR) spectroscopy, elemental analysis, and thermal analyses, including thermogravimetry (TG) and differential thermal analysis (DTA).

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.10a
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• pp.714-715
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• 2017

Much of the interest in ocean radiation detection has been heightened as a lot of radioactivity has leaked to the ocean due to the accident at the Fukushima nuclear power plant in Japan. In the study, MCNP simulation for radiation detection in the ocean was performed. Unlike in the air, the marine environment must ensure the stability of the sensor from water depth, temperature, pressure, and salinity. In the marine environment, too much radiation is shielded. Therefore, it is an object to select a housing with a low radiation shielding ratio.

• Journal of Radiation Industry
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• v.4 no.4
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• pp.359-364
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• 2010

PVDF-HFP (binder)/silylated alumina (inorganic particle)-coated PE (polyethylene) separators were with various compositions of binder and inorganic particle were prepared by a dip-coating process with humidity control (R.H. 25% and 50%) using electron beam irradiation. The morphology of the coated PVDF-$HFP/Al_2O_3$ layer with various compositions of PVDF-HFP and $Al_2O_3$, and humidity condition was found to be an important factor in determining ionic conductivity of the prepared separators. The PVDF-$HFP/Al_2O_3$ (5/5)-coated PE separator prepared at R.H. 50% followed by electron beam irradiation at 200 kGy was applied for lithium-ion polymer battery and the cell test results showed improved high-rate discharge performance and better cyclic stability compared to the cells with the bare PE and the PVDF-HFP-coated PE separators.

• Nuclear Engineering and Technology
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• v.56 no.6
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• pp.1943-1949
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• 2024

This study focuses on the comparative analysis of ABS polymer samples produced using two distinct manufacturing techniques: 3D printing and the sol-gel methods. In the first approach, ABS polymer was augmented with rare earth oxides, Er₂O₃ and Gd₂O₃, in nano powder form and fabricated into test specimens using 3D printing technology. In the second approach, identical samples were prepared via the sol-gel technique involving mold-based fabrication. Elemental content analysis revealed no significant differences between the samples produced by the two methods. The study proceeds to evaluate the gamma-ray shielding, neutron shielding, temperature resistance, and SEM/EDS pictures of ABS samples generated through both techniques. 3D printing method exhibited more favorable results in terms of structure morphology and thermal stability while there is no significant difference for radiation shielding. The results provide insights into the performance and suitability of each production method for radiation shielding applications. This research not only contributes to enhancing radiation shielding technology but also informs the selection of the most appropriate fabrication method for specific applications in nuclear technologies and diagnostic energy range in medical purposes.