• Korean Journal of Materials Research
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• v.27 no.5
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• pp.281-288
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• 2017

In this study, Fe-Ni slag, converter slag and dephosphorization slag generated from the steel industry, and fly ash or bottom ash from a power plant, were mixed at an appropriate mixing ratio and melted in a melting furnace in a mass-production process for glass ceramics. Then, glass-ceramic products, having a basalt composition with $SiO_2$, $Al_2O_3$, CaO, MgO, and $Fe_2O_3$ components, were fabricated through casting and heat treatment process. Comparison was made of the samples before and after the modification of the process conditions. Glass-ceramic samples before and after the process modification were similar in chemical composition, but $Al_2O_3$ and $Na_2O$ contents were slightly higher in the samples before the modification. Before and after the process modification, it was confirmed that the sample had a melting temperature below $1250^{\circ}C$, and that pyroxene and diopside are the primary phases of the product. The crystallization temperature in the sample after modification was found to be higher than that in the sample before modification. The activation energy for crystallization was evaluated and found to be 467 kJ/mol for the sample before the process modification, and 337 kJ/mol for the sample after the process modification. The degree of crystallinity was evaluated and found to be 82 % before the process change and 87 % after the process change. Mechanical properties such as compressive strength and bending strength were evaluated and found to be excellent for the sample after process modification. In conclusion, the samples after the process modification were evaluated and found to have superior characteristics compared to those before the modification.

• Korean Journal of Materials Research
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• v.8 no.9
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• pp.783-790
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• 1998

New process development of nuclear fuel fabrication for nuclear power plant was attempted by induction plasma technology with yttria-stabilized-zirconia ($\textrm{ZrO}_{2}$-$\textrm{Y}_{2}\textrm{O}_{3}$)powder, similar to $\textrm{UO}_{2}$, in the respect of melting point and physicochemical characteristics. Extent of powder melting was affected greatly by plasma plate power and particle size. Being optimized such as, sheath gas composition, probe position, particle size and spraying distance, dense deposit of 97.91% T.D. with deposition rate 20mm/min was attained at the condition of 120/20$\ell$/min of Ar/$\textrm{H}_{2}$ flow rate, 80kw of plate power, 8cm of probe position, 200Torr of chamber pressure and 18cm of spraying distance. The pellet of 96.5% of theoretical density was formed with homogeneity and nice exterior view at the best condition of deposition experiments, and the possibility of new nuclear pellet fabrication process was confirmed. The main and interrelated effects on deposit density were assessed by ANOVA(Ana1ysis of Variance).

• Journal of the Korean Geotechnical Society
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• v.38 no.8
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• pp.7-15
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• 2022

Most studies have conducted cryogenic triaxial compression tests with frozen specimens prepared in a separate mold by one-directional freezing. This method has the potential to generate residual stress in a frozen specimen and cannot be adopted to simulate the application of the artificial ground freezing method in the field. Therefore, in this study, novel equipment and procedure for the cryogenic triaxial compression test were proposed to overcome the limitations of existing test methods. Therefore, the mechanical characteristics of frozen sand, considering the effect of temperature and confining pressure, were evaluated. As the freezing temperature decreased, the brittleness of frozen sand increased, and the strength increased due to a decrease in the unfrozen water content and an increase in the ice strength. A higher confining pressure resulted in an increase in interparticle friction and the pressure melting phenomenon, which caused strength reduction. Thus, it was found that the mechanical behaviors of frozen sand were simultaneously affected by both temperature and confining pressure.

• Ecology and Resilient Infrastructure
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• v.3 no.4
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• pp.215-220
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• 2016

A new immobilization technique of nanoscale $TiO_2$ powder to expanded polystyrene (EPS) balls with temperature-controlled melting method was developed, and the photocatalytic activity of $TiO_2$ powder-embedded EPS balls were evaluated using methylene blue (MB) solution under ultraviolet irradiation (${\lambda}=254nm$). Based on the scanning electron microscope (SEM) images and associated energy-dispersive X-ray spectroscopy (EDX) analysis, the components of the intact EPS balls were mainly carbon and oxygen, whereas those of $TiO_2$-immobilized EPS balls were carbon, oxygen, and titanium, indicating that relatively homogenous patches of $TiO_2$ and glycerin film were coated on the surface of EPS balls. Based on the comparison of degradation efficiencies of MB between intact and $TiO_2$-immobilized EPS balls under UVC illumination, the degradation efficiencies of MB can be significantly improved using $TiO_2$-immobilized EPS balls, and surface reactions in heterogeneous photocatalysis were more dominant than photo-induced radical reactions in aqueous solutions. Thus, $TiO_2$-immobilized EPS balls were found to be an effective photocatalyst for photodegradation of organic compounds in aqueous solutions without further processes (i.e., separation, recycling, and regeneration of $TiO_2$ powder). Further study is in progress to evaluate the feasibility for usage of buoyant $TiO_2$-immobilized EPS to inhibit the excessive growth of algae in rivers and lakes.

• Nuclear Engineering and Technology
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• v.47 no.1
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• pp.11-25
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• 2015

The accident at Japan's Fukushima Daiichi nuclear power plant in March 2011, caused by an earthquake and a subsequent tsunami, resulted in a failure of the power systems that are needed to cool the reactors at the plant. The accident progression in the absence of heat removal systems caused Units 1-3 to undergo fuel melting. Containment pressurization and hydrogen explosions ultimately resulted in the escape of radioactivity from reactor containments into the atmosphere and ocean. Problems in containment venting operation, leakage from primary containment boundary to the reactor building, improper functioning of standby gas treatment system (SGTS), unmitigated hydrogen accumulation in the reactor building were identified as some of the reasons those added-up in the severity of the accident. The Fukushima accident not only initiated worldwide demand for installation of adequate control and mitigation measures to minimize the potential source term to the environment but also advocated assessment of the existing mitigation systems performance behavior under a wide range of postulated accident scenarios. The uncertainty in estimating the released fraction of the radionuclides due to the Fukushima accident also underlined the need for comprehensive understanding of fission product behavior as a function of the thermal hydraulic conditions and the type of gaseous, aqueous, and solid materials available for interaction, e.g., gas components, decontamination paint, aerosols, and water pools. In the light of the Fukushima accident, additional experimental needs identified for hydrogen and fission product issues need to be investigated in an integrated and optimized way. Additionally, as more and more passive safety systems, such as passive autocatalytic recombiners and filtered containment venting systems are being retrofitted in current reactors and also planned for future reactors, identified hydrogen and fission product issues will need to be coupled with the operation of passive safety systems in phenomena oriented and coupled effects experiments. In the present paper, potential hydrogen and fission product issues raised by the Fukushima accident are discussed. The discussion focuses on hydrogen and fission product behavior inside nuclear power plant containments under severe accident conditions. The relevant experimental investigations conducted in the technical scale containment THAI (thermal hydraulics, hydrogen, aerosols, and iodine) test facility (9.2 m high, 3.2 m in diameter, and $60m^3$ volume) are discussed in the light of the Fukushima accident.

• Korean Journal of Plant Tissue Culture
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• v.28 no.1
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• pp.7-13
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• 2001

Calli were induced from diploid and haploid tobacco after 4 weeks and maintained on MS medium with combination of 2.0 mg/L 2,4-D,0.1 mg/L BAP and 2.0 mg/L kinetin. Suspension cells were screened through 65 $\mu$m-nylon mesh and 100 $\mu$m-mesh, then they were smeared on selection medium combined with cadmium and PFP by using the low melting agarose of 0.8%. After 30days smeared cultures of the medium the cell was treated with 500 $\mu$M and 1000 $\mu$M to select the resistant cell line were selected. Plant regeneration was induced from the selected cell lines on medium with 0.5, 1.5, 2.0 mg/L BAP and on media with combination of auxin and BAP under 500 $\mu$M and 1000 $\mu$M cadmium. At this time, plant regeneration was achived on cadmium free medium. In case of haploid, occurred from the cell line which is selected in medium with cadmium and PFP. In case of diploid regeneration occurred is in the medium with cadmium alone. The plantlet regenerated from cadmium resistant calli grew well in cadmium 500 $\mu$M. Protein pattern of leaf, root, stem of regenerated plants was analyzed. The quantum was 6.5188 ug/mg.fr.wt in the leaf of plant, 5.3611 ug/mg.fr.wt in the stem, 3.0213 ug/mg.fr.wt in the root. On the other hand, 5.9652 ug/mg.fr.wt. in the leaf of control, 3.5974 ug/mg.fr.wt in the stem of the control, 4.3766 ug/mg.fr.wt. in the root of the control. The one dimension bends regenerated from cadmium resistant calli resistant to cadmium in leaf were 49 involving 198.7KD etc. Disappeared were 4 involving 160.5KD etc, The protein bends were combinized were 3 involving 83.4KD etc. The bends resistant to cadmium stress in stem were 41 involving 4.3KD etc. Disappeared were 5 involving 114.8KD etc. The protein bends combinized were 6 involving 128.7KD etc. The bends which had the resistance to cadmium stress in root is 27 in volving 166,9KD etc. The bends which disappeared were 198.7KD etc. There were 5 involving 83.4KD etc.

• Research in Plant Disease
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• v.18 no.4
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• pp.304-309
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• 2012

Fusarium wilt, caused by three races of Fusarium oxysporum f. sp. lycopersici, is one of the most important disease of tomato (Solanum lycopersicum) worldwide. A total of 1,906 tomato accessions were screened for the resistance to Fusarium wilt using I-3 SNP marker and high resolution melting analysis. Results showed that 97 accessions were homozygous resistant, 8 accessions were heterozygous resistant and 1,801 were homozygous susceptible. Accessions containing resistance were identified in 65 accessions of S. lycopersicum var. lycopersicum, 13 accessions of S. lycopericum var. cerasiform, 8 accessions of S. pimpinellifolium, 3 accessions of S. habrochaites, 3 accessions of S. corneliomulleri, 1 accession of S. galapagense, 3 accessions of S. peruvianum, 1 accession of S. chilense. For accurate evaluation of the Fusarium wilt resistance, however, screening to race 1 and race 2 and bio-assay still remain to be evaluated.

• Journal of Plant Biotechnology
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• v.44 no.4
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• pp.372-378
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• 2017

For comparison of the transcription profiles in apple (Malus domestica L.) cultivars differing in flesh color expression, two cDNA libraries were constructed. Differences in gene expression between red flesh apple cultivar, 'Redfield' and white flesh apple cultivar, 'Granny Smith' were investigated by next-generation sequencing (NGS). Expressed sequence tag (EST) of clones from the red flesh apple cultivar and white flesh apple cultivar were selected for nucleotide sequence determination and homology searches. High resolution melting (HRM) technique measures temperature induced strand separation of short PCR amplicons, and is able to detect variation as small as one base difference between red flesh apple cultivars and white flesh apple cultivars. We applied high resolution melting (HRM) analysis to discover single nucleotide polymorphisms (SNP) based on the predicted SNP information derived from the apple EST database. All 103 pairs of SNPs were discriminated, and the HRM profiles of amplicons were established. Putative SNPs were screened from the apple EST contigs by HRM analysis displayed specific difference between 10 red flesh apple cultivars and 11 white flesh apple cultivars. In this study, we report an efficient method to develop SNP markers from an EST database with HRM analysis in apple. These SNP markers could be useful for apple marker assisted breeding and provide a good reference for relevant research on molecular mechanisms of color variation in apple cultivars.

• Korean Journal of Plant Resources
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• v.32 no.4
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• pp.303-311
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• 2019

Various colors of fruit skin and flesh are the most popular commercial criteria for peach classification. In order to breed new red-fleshed peach cultivar, many cross seedlings and generations should be maintained. Therefore it is necessary to develop early selection markers to screen seedlings with target traits to increase breeding efficiency. For the comparison of transcription profiles in peach cultivars differing in flesh color expression, two cDNA libraries were constructed. Differences in gene expression between red-fleshed peach cultivar, 'Josanghyeoldo' and white-fleshed peach cultivar, 'Mibaekdo' were analyzed by next-generation sequencing (NGS). Expressed sequence tag (EST) of clones from the two cultivars were selected for nucleotide sequence determination and homology searches. Putative single nucleotide polymorphisms (SNP) were screened from peach EST contigs by high resolution melting (HRM) analysis displayed specific difference between 8 red-fleshed peach cultivars and 24 white-fleshed peach cultivars. All 72 pairs of SNPs were discriminated and the HRM profiles of amplicons were established. In the study reported here, the development of SNP markers for distinguishing between red and white fleshed peach cultivars by HRM analysis offers the opportunity to use DNA markers. This SNP marker could be useful for peach marker assisted breeding and provide a good reference for relevant research on molecular mechanisms of color variation in peach cultivars.

• Korean Journal of Plant Resources
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• v.34 no.5
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• pp.443-450
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• 2021

Peach flesh color is commercially important criteria for classification and has implications for nutritional quality. To breed new yellow-fleshed peach cultivar many cross seedlings and generations should be maintained. Therefore it is necessary to develop early selection molecular markers for screening cross seedlings and germplasm with economically important traits to increase breeding efficiency. For the comparison of transcription profiles in peach varieties with a different flesh color expression, two cDNA libraries were constructed. Differences in gene expression between yellow-fleshed peach cultivar, 'Changhowon Hwangdo' and white-fleshed peach cultivar, 'Mibaekdo' were analyzed by next-generation sequencing (NGS). Expressed sequence tag (EST) of clones from the two varieties was selected for nucleotide sequence determination and homology searches. Putative single nucleotide polymorphisms (SNPs) were screened from peach EST contigs by high resolution melting (HRM) analysis, SNP ID ppa002847m:cds and ppa002540m:cds displayed specific difference between 17 yellow-fleshed and 21 white-fleshed peach varieties. The SNP markers for distinguishing yellow and white fleshed peach varieties by HRM analysis offers the opportunity to use early selection. This SNP markers could be useful for marker assisted breeding and provide a good reference for relevant research on molecular mechanisms of color variation in peach varieties.