• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.293-293
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• 2022

This study is to develop new wheat breeding material through wide hybridization with wild species harboring useful characteristics such as salt, heat, and drought tolerance. Leymus mollis, wild rye was used to improve wheat genetic quality. L. mollis, is a perennial plant harboring tolerance against salt, heat, and drought because L. mollis distributes on the seaside. The F₁ hybrids were produced by crossing between common wheat (Triticum aestivum L., Chinese Spring) and L. mollis. Genomic in situ hybridization revealed that the F₁ hybrids have L. mollis genome. For the evaluation of salt and drought tolerance, seeds from the F₂ were used. Under 2% NaCl solution, the F₃ wheat-Leymus addition plants with salt tolerance showed more tillering and longer roots than other F₃ plants without salt tolerance. Also, the F₃ plants with salt tolerance showed better shallow-rooted than other F₃ plants without salt tolerance. Finally, the F₃ plants with salt tolerance made seed-setting under 2% NaCl condition, but other F₃ plants without salt tolerance were not. Under drought conditions, the F₃ plants with drought tolerance showed longer culm and spike length than other F₃ plants without drought tolerance and even those of Chinese Spring under well-water conditions. We evaluated and selected the F₃ plants with salt or drought tolerance for generation advancement.

• Nuclear Engineering and Technology
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• v.56 no.3
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• pp.1013-1021
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• 2024

A series of experiments were performed to produce a fuel source for a molten salt reactor (MSR) through pyroprocessing technology. A simulated LiCl-KCl-UCl₃-NdCl₃ salt system was prepared, and the U element was fully recovered using a liquid cadmium cathode (LCC) by applying a constant current. As a result, the salt was purified with an UCl₃ concentration lower than 100 ppm. Subsequently, the U/RE ingot was prepared by melting U and RE metals in Y₂O₃ crucible at 1473 K as a surrogate for RE-rich ingot product from pyroprocessing. The produced ingot was sliced and used as a working electrode in LiCl-KCl-LaCl₃ salt. Only RE elements were then anodically dissolved by applying potential at - 1.7 V versus Ag/AgCl reference electrode. The RE-removed ingot product was used to produce UCl₃ via the reaction with NH4Cl in a sealed reactor.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.18 no.3
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• pp.373-382
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• 2020

This study proposes a method of separating uranium (U) and minor actinides from rare earth (RE) elements in the LiCl-KCl salt system. Several RE metals were used to reduce UCl₃ and MgCl₂ from the eutectic LiCl-KCl salt systems. Five experiments were performed on drawdown U and plutonium (Pu) surrogate elements from RECl₃-enriched LiCl-KCl salt systems at 773 K. Via the introduction of RE metals into the salt system, it was observed that the UCl₃ concentration can be lowered below 100 ppm. In addition, UCl₃ was reduced into a powdery form that easily settled at the bottom and was successfully collected by a salt distillation operation. When the RE metals come into contact with a metallic structure, a galvanic interaction occurs dominantly, seemingly accelerating the U recovery reaction. These results elucidate the development of an effective and simple process that selectively removes actinides from electrorefining salt, thus contributing to the minimization of the influx of actinides into the nuclear fuel waste stream.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.18 no.3
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• pp.337-346
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• 2020

Two commonly used ceramics in molten salt research are alumina and mullite. The two ceramics were exposed to a combination of rare earth chlorides (YCl₃, SmCl₃, NdCl₃, PrCl₃, and CeCl₃; each rare earth chloride of 1.8 weight percent) in LiCl-KCl at 773 K for approximately 13 days. Scanning electron microscopy with wave dispersion spectra was utilized to investigate a formation layer or deposition of rare earths onto the ceramic. Only the major constituents of the ceramics (Al, Si, and O₂) were observed during the wave dispersion spectra. X-ray fluorescence was used as well to determine concentration changes in the molten salt as a function of ceramic exposure time. This study shows no evidence of ionic exchange or layer formation between the ceramics and molten chloride salt mixture. There are signs of surface tension effects of molten salt moving out of the tantalum crucible into secondary containment.

• 한국지구물리탐사학회:학술대회논문집
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• 2007.06a
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• pp.113-117
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• 2007

Sub-salt imaging is an unsolved hot issue in subsurface imaging area. We tested several important properties in imaging sub-salt structures to provide a clue to this problem. Reverse time migration using velocity models obtained by waveform inversion produced better results than that of stacking velocity analysis. Sub-salt imaging results were highly dependent on the size and shape of a salt structure. The results were not clear when the velocity of a salt structure is significantly higher than that of adjacent layers.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.31 no.5
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• pp.197-202
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• 2021

Synthesis of Z-type hexaferrite Ba₃Co₂Fe₂₄O₄₁ (Ba₃Z) and Ba_1.5La_1.5Co₂Fe₂₄O₄₁ (Ba_1.5La_1.5Z) powders were tried using molten salt synthesis after primary calcination. Ba₃Z calcined at 1000℃ was formed with both M-type and Y-type hexaferrite, and then Z-type was obtained when sintered with molten salt at 1150℃ and 1200℃. In the case of Ba_1.5La_1.5Z calcined at 1000℃, however, M-type hexaferrite, CoFe₂O₄ (Spinel phase), and LaFeO₃ were synthesized. As a result, Z-type hexaferrite was not synthesized after sintering with molten salt. In addition, the aspect ratio of the particles decreased as the sintering temperature increased with molten salt synthesis. To obtain a single-phase Ba_1.5La_1.5Z with a high aspect ratio, it is expected the raw materials have to calcine below the temperature of a spinel phase formation before sintering with molten salt.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.20 no.1
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• pp.43-63
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• 2022

The aim of this review is to communicate some essential knowledge of the underlying mechanism of the corrosion of structural containment alloys during molten salt reactor operation in the context of prospective online monitoring in future MSR installations. The formation of metal halide species and the progression of their concentration in the molten salt do reflect containment corrosion, tracing the depletion of alloying metals at the alloy salt interface will assure safe conditions during reactor operation. Even though the progress of alloying metal halides concentrations in the molten salt do strongly understate actual corrosion rates, their prospective 1^st order kinetics followed by near-linearly increase is attributed to homogeneous matrix corrosion. The service life of the structural containment alloy is derived from homogeneous matrix corrosion and near-surface void formation but less so from intergranular cracking (IGC) and pitting corrosion. Online monitoring of corrosion species is of particular interest for molten chloride systems since besides the expected formation of chromium chloride species CrCl₂ and CrCl₃, other metal chloride species such as FeCl₂, FeCl₃, MoCl₂, MnCl₂ and NiCl₂ will form, depending on the selected structural alloy. The metal chloride concentrations should follow, after an incubation period of about 10,000 hours, a linear projection with a positive slope and a steady increase of < 1 ppm per day. During the incubation period, metal concentration show 1^st order kinetics and increasing linearly with time^1/2. Ideally, a linear increase reflects homogeneous matrix corrosion, while a sharp increase in the metal chloride concentration could set a warning flag for potential material failure within the projected service life, e.g. as result of intergranular cracking or pitting corrosion. Continuous monitoring of metal chloride concentrations can therefore provide direct information about the mechanism of the ongoing corrosion scenario and offer valuable information for a timely warning of prospective material failure.

• Economic and Environmental Geology
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• v.55 no.3
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• pp.281-293
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• 2022

We examined degradation characteristics of lead based pigments(white lead, Red lead, Litharge) according to atmospheric environmet condition, for example atmospheric gas(CO₂, NO₂) and soluble salt. Painted samples not changed material compositions but were occured the color change(𝚫E 4~31) after exposed UV irradiation. All sample were not affected by CO₂ gas not only color but chemical composition. However, samples were remakably changed color exposed NO₂ gas and it was formed secondary product like as lead nitrate. Such as red lead and white lead samples' color difference were 𝚫E 2 and 𝚫 10 respectively and became dark, along with litharge became bright and color difference was 𝚫E 5 after react with NO₂ gas. It confirm that NO₂ was influential factor than CO₂ in the case of same concentration. Furthermore salt spray test was taken to figure out soluble salt influence in fine dust. The result showed noticeable color change and secondary product was formed on samples' surface. The glue film peeled off or hole, and color changed around the secondary products. After salt spray, XRD pattern showed decrease peak intensity and lower crystalinity. As a result of salt spray test, white lead was formed new product litharge and litharge was formed litharge and minium. According to the results, influential atmospheric factors for conservation of paint pigments were UV, NO₂, soluble salt, and litharge was most weakness throughout lead base pigments.

• Journal of The Korean Society of Grassland and Forage Science
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• v.43 no.1
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• pp.56-61
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• 2023

The germination process is critical for plant growth and development and it is largely affected by environmental stress, especially salinity. Recently, hydrogen sulfide (H₂S) is well known to act as a signaling molecule in a defense mechanism against stress conditions but poorly understood regulating seed germination. In this study, the effects of NaHS (the H₂S donor) pretreatment on various biochemical (hydrogen peroxide (H₂O₂) content and amylase and protease activity) and physiological properties (germination rate) during seed germination of oilseed rape (Brassica napus L. cv. Mosa) were examined under salt stress. The seed germination and seedling growth of oilseed rape were inhibited by NaCl treatment but it was alleviated by NaHS pretreatment. The NaCl treatment increased H₂O₂ content leading to oxidative stress, but NaHS pre-treatments maintained much lower levels of H₂O₂ in germinating seeds under salt stress. Amylase activity, a starch degradation enzyme, significantly increased over 2-fold in control, NaHS pretreatment, and NaHS pretreatment under NaCl during seed germination compared to NaCl treatment. Protease activity was highly induced in NaHS-pretreated seeds compared to NaCl treatment, accompanied by a decrease in protein content. These results indicate that NaHS pretreatment could improve seed germination under salt stress conditions by decreasing H₂O₂ accumulation and activating the degradation of protein and starch to support seedling growth.

• Biotechnology and Bioprocess Engineering:BBE
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• v.6 no.1
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• pp.37-41
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• 2001

HPLC separation of ionic samples tends to be more complicated and difficult to understand than that of non-ionic compounds. On the other hand, band spacing is much more easily manipulated for ionic than for neutral samples. Ion-suppression RP-HPLC method was used with organic modifier and aqueous buffer solution. In this work, five mononucleotides of cytidine-5-monophosphate (5-CMP) disodium salt, uridine-5-monophosphate disodium salt (5-UMP), guanosine-5-monophosphate disodium salt (5-GMP), inosine-5-monophosphate disodium salt (5-IMP), and adenosine-5-monophosphate disodium salt (5-AMP) were examined. Acetic acid and sodium phosphate were used as buffers, and methanol as an organic modifier. A new relationship between the retention factor and the buffer concentration at a fixed modifier content (5% of methanol) could be expressed by following: K = (k(sub)-1 + k(sub)0 (k(sub)B/k(sub)S)/(1 + (k(sub)B/k(sub)S) C(sub)B(sup)a), where C(sub)B was the concentration of buffer. Using this relationship, the calculated values closely matched the experimental data. The derived relationship showed that as the buffer concentration increased, the retention factor approached a certain value, and this was buffer dependent.