• Journal of Ginseng Research
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• v.21 no.3
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• pp.147-152
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• 1997

Ginsenosides $Rh_1$ and $Rh_2$ Induced the differentiation of F9 teratocarcinoma stem cells. These agents are structurally similar to the steroid hormones, therefore, we speculated that the steroid receptor (s) or novel nuclear receptor (s) could be involved in the differentiation process induces by them. Based on this speculation, we tried to alone new nuclear receptors with reverse transcription-polymerase chain reaction (RT-PCR) method by isolating RNA from F9 teratocarcinoma cells induced by ginsenosides. By using RT-PCR with degenerated primers from highly conserved DNA binding domain of nuclear receptors, we identified several nuclear receptors. In northern blot analysis we found that these clones are transcriptionally regulated by ginsenoside Rhl or Rh2 treatment. Further characterizations of these clones are needed to identify the mechanism of gene expression, which has an important role in the differentiation of F9 cells induced by ginsenosides.

• Applied Microscopy
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• v.17 no.1
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• pp.1-15
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• 1987

Testes from the allied rock wallaby(Petrogale assimilus) have been examined by the electron microscopy in thin sections in order to examine spermiogenesis and structure of spermatozoa. The spermiogenesis can be divided into nine stages: early Golgi, late Golgi, collapsing, nuclear protrusion, condensation and flattening, nuclear shaping, rotation, nuclear ring contraction, and maturation. The acrosome has been abruptly formed following the collapse of expanded acrosomal vesicle without the cap stage described in the eutheria. The flatly condensed nucleus rotates obliquely to the axis of the axial filament complex and the folded acrosome covers the anterior third of the dorsal nuclear surface forming a wide subacrosormal space as the nuclear ring has contracted. The Sertoli cell reaction and spur are prominent during the nuclear protrusion and rotation stages. A mature spermatozoon has S-shape head which has an extended part reaching to the vicinity of the middle piece.

• Nuclear Engineering and Technology
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• v.49 no.3
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• pp.592-597
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• 2017

Three plastic scintillators of 4.5 cm diameter and 2.5-cm length were fabricated for comparison with commercial plastic scintillators using polymerization of the styrene monomer 2.5-diphenyloxazole (PPO) and 1,4-bis benzene (POPOP). Their maximum emission wavelengths were determined at 426.06 nm, 426.06 nm, and 425.00 nm with a standard error of 0.2% using a Varian spectrophotometer (Agilent, Santa Clara, CA, USA). Compton edge spectra were measured using three gamma ray sources [i.e., cesium 137 ($^{137}Cs$), sodium 22 ($^{22}Na$), and cobalt 60 ($^{60}Co$)]. Energy was calibrated by analyzing the Compton edge spectra. The fabricated scintillators possessed more than 99.7% energy linearity. Light output was comparable to that of the BC-408 scintillator (Saint-Gobain, Paris, France). The fabricated scintillators showed a light output of approximately 59-64% of that of the BC-408 scintillator.

• Nuclear Engineering and Technology
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• v.51 no.3
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• pp.915-921
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• 2019

Radiation damage due to neutrons has been calculated in Ni-based alloys in Wolsong CANDU reactor environments. Two damage parameters are considered: displacement damage, and transmutation gas production. We used the SPECTER and SRIM computer codes in quantifying radiation damage. In addition, damage caused by Ni two-step reactions was considered. Estimations were made for the annulus spacers in a CANDU reactor that are located axially along a fuel channel and made of Inconel X-750. The calculation results indicate that the transmutation gas production from the Ni two-step reactions is predominant as the effective full power year increases. The displacement damage due to recoil atoms produced from Ni two-step reactions accounts for over 30% out of the total displacement damage.

• Nuclear Engineering and Technology
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• v.53 no.1
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• pp.142-147
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• 2021

Hydrogen peroxide is a radiolysis product of water formed under gamma-irradiation; therefore, its reliable detection is crucial in the nuclear industry for spent fuel management and coolant chemistry. This study proposes an electrochemical sensor for hydrogen peroxide detection. Cysteamine (CYST), gold nanoparticles (GNPs), and horseradish peroxidase (HRP) were used in the modification of a gold electrode for fabricating Au/CYST/GNP/HRP sensor. Each modification step of the electrode was investigated through electrochemical and physical methods. The sensor exhibited strong sensitivity and stability for the detection and measurement of hydrogen peroxide with a linear range of 1-9 mM. In addition, the Michaelis-Menten kinetic equation was applied to predict the reaction curve, and a quantitative method to define the dynamic range is suggested. The sensor is highly sensitive to H₂O₂ and can be applied as an electrochemical H₂O₂-sensor in the nuclear industry.

• Nuclear Engineering and Technology
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• v.56 no.5
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• pp.1895-1901
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• 2024

The fission model, G4ParaFissionModel, was enhanced in this study, mainly focusing on refining the energy dependence of the peak-to-valley ratio in the mass distribution and the energy dependence of the average total kinetic energy (TKE). The enhanced model was employed to investigate the characteristics of fission products from ²³⁵U(n, f) reaction. The calculated results, including fission yield, TKE distribution, prompt fission neutron and gamma spectra, were compared with both evaluated and experimental data. The comparison shows that these physical observables related nuclear data, which are of importance for developments of the nuclear power and physics, can be reasonably well reproduced.

• Journal of the Earthquake Engineering Society of Korea
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• v.19 no.1
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• pp.37-43
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• 2015

This paper presents a detailed procedure for a nonlinear soil-structure interaction of a seismically isolated NPP(Nuclear Power Plant) structure using the boundary reaction method (BRM). The BRM offers a two-step method as follows: (1) the calculation of boundary reaction forces in the frequency domain on an interface of linear and nonlinear regions, (2) solving the wave radiation problem subjected to the boundary reaction forces in the time domain. For the purpose of calculating the boundary reaction forces at the base of the isolator, the KIESSI-3D program is employed in this study to solve soil-foundation interaction problem subjected to vertically incident seismic waves. Wave radiation analysis is also employed, in which the nonlinear structure and the linear soil region are modeled by finite elements and energy absorbing elements on the outer model boundary using a general purpose nonlinear FE program. In this study, the MIDAS/Civil program is employed for modeling the wave radiation problem. In order to absorb the outgoing elastic waves to the unbounded soil region, spring and viscous-damper elements are used at the outer FE boundary. The BRM technique utilizing KIESSI-3D and MIDAS/Civil programs is verified using a linear soil-structure analysis problem. Finally the method is applied to nonlinear seismic analysis of a base-isolated NPP structure. The results show that BRM can effectively be applied to nonlinear soil-structure interaction problems.

• Analytical Science and Technology
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• v.18 no.4
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• pp.263-270
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• 2005

Nuclear track is an useful tool for elemental analysis of radionuclides, such as uranium, plutonium and thorium, etc., and for elements undergoing nuclear reactions with thermal neutrons such as lithium and boron. This method has various application fields such as detecting fissionable radionuelides, measuring the fission rate in nuclear technology, analyzing cosmic radiation from meteorite, calculating the age of minerals as well as their history, etc. Track registration method has been applied to the microscopic analysis of boron and fissionable element such as uranium in KAERI. This report reviews the theoretical background of the nuclear track formation, practical procedures to obtain etched tracks and a perspective of the future.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.19 no.2
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• pp.271-278
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• 2021

In this study, a chlorination technique for recycling Li₂ZrO₃, a reaction product of ZrO₂-assisted rinsing process, was investigated to minimize the generation of secondary radioactive pyroprocessing waste. It was found that the reaction temperature was a key parameter that determined the reaction rate and maximum conversion ratio. In the temperature range of 400-600℃, an increase in the reaction temperature resulted in a profound increase in the reaction rate. Hence, according to the experimental results, a reaction temperature of at least 450℃ was proposed to ensure a Li₂ZrO₃ conversion ratio that exceeded 80% within 8 h of the reaction time. The activation energy was found to be 102 ± 2 kJ·mol^-1·K^-1 between 450 and 500℃. The formation of LiCl and ZrO₂ as reaction products was confirmed by X-ray diffraction analysis. The experimental results obtained at various total flow rates revealed that the overall reaction rate depends on the Cl₂ mass transfer rate in the experimental condition. The results of this study prove that the chlorination technique provides a solution to minimize the amount of radioactive waste generated during the ZrO₂-assisted rinsing process.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.19 no.2
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• pp.225-231
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• 2021

The reaction between Li₂CO₃ and Cl₂ was investigated to verify its occurrence during a carbon-anode-based oxide reduction (OR) process. The reaction temperature was identified as a key factor that determines the reaction rate and maximum conversion ratio. It was found that the reaction should be conducted at or above 500℃ to convert more than 90% of the Li₂CO₃ to LiCl. Experiments conducted at various total flow rate (Q) / initial sample weight (W_i) ratios revealed that the reaction rate was controlled by the Cl₂ mass transfer under the experimental conditions adopted in this work. A linear increase in the progress of reaction with an increase in Cl₂ partial pressure (pCl₂) was observed in the pCl₂ region of 2.03-10.1 kPa for a constant Q of 100 mL·min^-1 and W_i of 1.00 g. The results of this study indicate that the reaction between Li₂CO₃ and Cl₂ is fast at 650℃ and the reaction is feasible during the OR process.