• Journal of Microbiology and Biotechnology
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• v.24 no.2
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• pp.133-143
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• 2014

The development of the gut is controlled and modulated by different interacting mechanisms, such as genetic endowment, intrinsic biological regulatory functions, environment influences and last but no least, the diet influence. In this work, we compared the fecal microbiota of breast-fed (BF), formula-fed (FF), and mixed-fed (MF) infants from Hebei Province, China. By using high-throughput 16S rDNA sequencing analyses, we found some differences in gut microbiota in the three groups. Firmicutes and Proteobacteria were the dominant bacteria at the phylum level in the three groups, where FF infants showed a significant depletion in Bacteroidetes (p < 0.001) and Actinobacteria (p < 0.05). Enterobacteriaceae was the dominant bacteria at the family level in the three groups, but FF infants showed higher Enterobacteriaceae enrichment than BF and MF infants (p < 0.05); the abundance of the Bifidobacteriaceae was only 8.16% in the feces of BF infants, but higher than in MF and FF infants (p < 0.05). The number of genera detected (abundance >0.01%) in BF, MF, and FF infants was only 15, 16, and 13, respectively. This study could provide more accurate and scientific data for the future study of infant intestinal flora.

• Proceedings of KOSOMES biannual meeting
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• 2006.11a
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• pp.163-168
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• 2006

In order to develop the deep ocean water, we performed to study the characteristics of vertical distribution of dissolved trace metals(Cd, Co, Cu, Ni, Pb, Zn) from Apr. to Oct., 2005 in the East Sea. Total six sampling sites were selected in Gangwon-Do and Gyeongsanbuk-Do. Accuracy of the analytical procedures was assessed by the SRM(CASS-4) for dissolved metals in seawater. The mean recoveries of CASS-4 ranged from 89.4% for Co to 99.8% for Cd. In this study, the dissolved metal concentrations varied with space, time and element. The metal concentrations showed wide range in the surface. Cd, Ni and Zn showed a nutrient-type profile with surface depletion and enrichment at depth. However, Co, Cu and Pb were irregular in the vertical distribution. All metal concentrations studied in this study are lower than the criteria of Korean drinking water.

• Journal of Korean Society of Forest Science
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• v.98 no.2
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• pp.170-177
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• 2009

There are remarkable differences in growth and morphological characters of roots between mountain and field cultivated Panax ginseng. Growth of root in mountain cultivated ginseng was much slower than that of field cultivated ginseng. However, the factor affecting the retarded growth in mountain ginseng was not known. Soil analysis revealed that phosphorus (P) content of mountain soil was exceptionally low at least ten-fold lower compared to that of field soil. Thus, we suggest that low availability of P in mountain soil may be one of the limiting factors for growth of ginseng in mountain soil environment. We had monitored the growth of ginseng plants after one and three years of phosphate fertilizer application. Three kinds of phosphate fertilizers: fused magnesium phosphate, fused superphosphate, and single superphosphate were applied to mountain soil. Application of phosphate fertilizers increased the fresh-, dry weight, and diameter of ginseng roots and resulted in increased P accumulation in roots. These results demonstrate that slow growth of ginseng in mountain soil environment might be attributed to the low P content in mountain soil. Thus, analysis of P amount in mountain soil will be a good indicator for the selection of suitable site the ginseng cultivation in forest.

• Journal of Radiation Protection and Research
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• v.39 no.4
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• pp.176-181
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• 2014

The object of this paper is to evaluate the fission product inventories and radiological doses in a non-LOCA event, based on the U.S. NRC's regulatory methodologies recommended by the TID-14844 and the RG 1.195. For choosing a non-LOCA event, one fuel assembly was assumed to be melted by a channel blockage accident. The Hanul nuclear power reactor unit 6 and the CE $16{\times}16$ fuel assembly were selected as the computational models. The burnup cross section library for depletion calculations was produced using the TRITON module in the SCALE6.1 computer code system. Based on the recently licensed values for fuel enrichment and burnup, the source term calculation was performed using the ORIGEN-ARP module. The fission product inventories released into the environment were obtained with the assumptions of the TID-14844 and the RG 1.195. With two kinds of source terms, the radiological doses of public in normal environment reflecting realistic circumstances were evaluated by applying the average condition of meteorology, inhalation rate, and shielding factor. The statistical analysis was first carried out using consecutive three year-meteorological data measured at the Hanul site. The annual-averaged atmospheric dispersion factors were evaluated at the shortest representative distance of 1,000 m, where the residents are actually able to live from the reactor core, according to the methodology recommended by the RG 1.111. The Korean characteristic-inhalation rate and shielding factor of a building were considered for a series of dose calculations.

• Nuclear Engineering and Technology
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• v.51 no.6
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• pp.1708-1714
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• 2019

The purpose of the critical evaluation of the spent fuel pool (SFP) is to verify that the maximum effective multiplication factor ($K_{eff}$) is less than the critical safety limit at 100% stored condition of the spent fuel with the maximum reactivity. At nuclear power plants, the storage standard of spent fuel, ie, the loading curve, is established to prevent criticality from being generated in SFP. Here, the loading curve refers to a graph showing the minimum discharged burnup versus the initial enrichment of spent fuel. Recently, US NRC proposed the new critical safety assessment guideline (DSS-ISG-2010-01, Revision 0) of PWR SFPs and most of utilities in US is following it. Of course, the licensed criterion of the maximum effective multiplication factor of SFP remains unchanged and it should be less than 0.95 from the 95% probability and the 95% confidence level. However, the new guideline is including the new evaluation methodologies like the application of the axial burnup profile, the validation of depletion and criticality code, and trend analysis. Among the new evaluation methodologies, the most important factor that affects $K_{eff}$ is the axial burnup profile of spent fuel. US NRC recommends to consider the axial burnup profiles presented in NUREG-6801 in criticality analysis. In this paper, criticality effect was evaluated considering three profiles, respectively: i) Axial burnup profiles presented in NUREG-6801. ii) Representative PWR axial burnup profile. iii) Uniform axial burnup profile. As the result, the case applying the axial burnup profiles presented in NUREG-6801 showed the highest $K_{eff}$ among three cases. Therefore, we need to introduce a new methodology because it can be issued if the axial burnup profiles presented in NUREG/CR-6801 are applied to the domestic nuclear power plants without any other consideration.

• Corrosion Science and Technology
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• v.20 no.3
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• pp.158-168
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• 2021

Austenitic 316 stainless steel was irradiated with protons accelerated by an energy of 2 MeV at 360 ℃, the various defects induced by this proton irradiation were characterized with microscopic equipment. In our observations irradiation defects such as dislocations and micro-voids were clearly revealed. The typical irradiation defects observed differed according to depth, indicating the evolution of irradiation defects follows the characteristics of radiation damage profiles that depend on depth. Surface oxidation tests were conducted under the simulated primary water conditions of a pressurized water reactor (PWR) to understand the role irradiation defects play in surface oxidation behavior and also to investigate the resultant irradiation assisted stress corrosion cracking (IASCC) susceptibility that occurs after exposure to PWR primary water. We found that Cr and Fe became depleted while Ni was enriched at the grain boundary beneath the surface oxidation layer both in the non-irradiated and proton-irradiated specimens. However, the degree of Cr/Fe depletion and Ni enrichment was much higher in the proton-irradiated sample than in the non-irradiated one owing to radiation-induced segregation and the irradiation defects. The microstructural and microchemical changes induced by proton irradiation all appear to significantly increase the susceptibility of austenitic 316 stainless steel to IASCC.

• Economic and Environmental Geology
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• v.56 no.3
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• pp.259-275
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• 2023

Pan African granitoids of Kaiama is comprised of K-feldspar rich granites, porphyritic granites, and granitic gneiss that are intruded by quartz veins and aplitic veins and dykes which trend NE-SW. In order to establish the geochemical signatures, petrogenesis, and tectonic settings of the lithological units, petrological, petrographical, and geochemical studies was carried out. Petrographic analysis reveals that the granitoids are dominantly composed of quartz, plagioclase feldspar, biotite, and k-feldspar with occasional muscovites, sericite, and opaque minerals that constitute very low proportion. Major, trace, and rare earth elements geochemical data reveal that the rocks have moderate to high silica (SiO₂=63-79.7%) and alumina (Al₂O₃=11.85-16.15) contents that correlate with the abundance of quartz, feldspars, and biotite. The rocks are calc-alkaline, peraluminous (ASI=1.0-<1.2), and S-type granitoids sourced by melting of pre-existing metasedimentary or sedimentary rocks containing Al, Na, and K oxides. They plot dominantly in the WPG and VAG fields suggesting emplacement in a post-collisional tectonic setting. On a multi-element variation diagram, the granitoids show depletion in Ba, K, P, Rb, and Ti while enrichment was observed for Th, U, Nd, Pb and Sm. Their rare-earth elements pattern is characterized by moderate fractionation ((La/Yb)_N=0.52-38.24) and pronounced negative Eu-anomaly (Eu/Eu^*=0.02-1.22) that points to the preservation of plagioclase from the source magma. Generally, the geochemical features of the granitoids show that they were derived by the partial melting of crustal rocks with some input from greywacke and pelitic materials in a typical post-collisional tectonic setting.

• The Journal of Engineering Geology
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• v.15 no.3
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• pp.349-363
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• 2005

Many Quaternary faults are recognized as thin gouge and narrow cataclastic zone juxtaposing the Bulguksa granite and Quaternary deposit bed in the eastern block of the Using Fault, Korea: Gaegok 1, Caegok 2, Singye, Madong Wonwonsa and Jinhyeon faults. This study was performed to calculate chemical change, volume change, silica loss and fluid-rock ratio taken place in gouge zones of these Quaternary faults using XRF, XRD, EPMA. The chemical compositions of fault rocks reveal that the fault gouges are depleted in $SiO_2,\;Na_2\;O,and\;K_2O$ and enriched in $Al_2O_3,\;Fe_2O_3,\;P_2O_5,\;MgO,\;MnO,\;CaO,\;and\;LOI(H_2O+CO_2)$ relative to protoliths. The fact that there is enrichment of relatively immobile elements and depletion of the more soluble elements in the fault gouges relative to protoliths can be explained by fluid-assisted volume loss of $56\%$ for Caegok 1 fault, $22\%$ for Caegok 2 fault,$34\%$, for Singye fault, $8\%$ for Madong fault, $2\%$ for the Wonwonsa fault and $53\%$ for the linhyeon fault. Madong fault and Wonwonsa fault where ratios of the volume change, silica loss and fluid-rock are low might have acted as a closed system for fluid activity, whereas Caegok 1 fault and Jinhyeon fault with high ratios in those factors be an open system. The volumetric fluid-rock ratios range $10^2\sim10^4$ for all faults, being highest in Caegok 1 fault and Jinhyeon fault whose fluid activity was most significant.

• Economic and Environmental Geology
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• v.26 no.3
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• pp.337-347
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• 1993

Mineralogical and geochemical studies on some pyrophyllite deposits in Milyang area, Kyeongnam Province (Milyang and Sungjin mine) were carried out in order to investigate dispersion patterns of chemical elements in altered volcanic wallrocks, and to interpret genetic environments of the pyrophyllite deposits. Cretaceous andesitic and tuffaceous rocks, and pyrophyllite ore specimens were collected from the dumps and drilling cores. Andesitic wallrocks were grouped as unaltered and altered rocks in the order of pyrophyllitization. Vertical dispersion patterns and relative mobilities of chemical elements in volcanic wallrocks were discussed. Geochemical environment in the Milyang area is characterized by the occurrence of boron minerals such as dumortierite coexisting with pyrophyllite ores, and tourmaline in granitic rocks. Unaltered andesitic rocks are mainly composed of plagioclase, pyroxene and hornblende, and were propylitized and saussuritized. Altered andesitic rocks are bleached and consist of quartz, sericite, pyrophyllite, kaolinite, chlorite and disseminated pyrite. Pyrophyllite ores are mainly composed of quartz, pyrophyllite, dumortierite, dissemianted pyrite and some diaspore. Enrichment of $SiO_2$, $Al_2O_3$, LOI (loss on ignition), As and Cr, and depletion of $K_2O$, $Na_2O$, CaO, MgO and total Fe are characteristic during alteration process. The REE patterns show that the pyrophyllite deposits could be originated from the continental margin volcanics. The $(La/Lu)_{cn}$ ratios of the pyrophyllite ores increase from 4.2~23.2 to 2.67~128.8 owing to strong acidic hydrothermal alteration. Vertical dispersion patterns of $Al_2O_3$, $K_2O$, $Na_2O$, CaO, MgO, $Fe_2O_3$ (total Fe), As, Au, Sb, Cr and Sr in the wallrocks show the location of orebodies. Particularly dispersion patterns of $Al_2O_3$ and Cr indicate the extension of orebodies. Anomalous distribution of Au, As and Sb in wallrocks shows potential for gold occurrence below the pyrophyllite deposits. Judging from the relative mobilities of elements in wallrocks, $Al_2O_3$ could be added from hydrothermal solution, and the silicified rone be formed from the excess of $SiO_2$.

• Economic and Environmental Geology
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• v.46 no.5
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• pp.391-409
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• 2013

The Hongseong area of the southwestern Gyeonggi massif is considered to be part of suture zone that is tectonically correlated with the Qinling-Dabie-Sulu belt of China in terms of the preservation of collisional evidences during Triassic in age. The Wolhyeonri complex, preserved at the center of the Hongseong area, consists mainly of Neoproterozoic orthogneisses and Middle Paleozoic intermediate- to high-grade metamorphic schists, orthogneisses and mafic metavolcanics. The area includes various Middle to Late Triassic intrusives (e.g. dyke or stock). They are mainly monzonite and aplite with small intrusions of monzodiorit, syenite and diorite in composition. The SHRIMP U-Pb zircon ages yield 237 Ma to 222 Ma. The geochemistry of the studied Triassic intrusives show similar subuction- or arc-type signatures having Ta-Nb troughs, depletion of P and Ti, and enrichment of LILEs (large ion lithophile elements). In addition, the Triassic plutons in the Hongseong area, including those from this study, mostly possess high-K calc-alkaline to shoshonitic tectonic affinity. These results could be tectonically correlated to the post-collisional magmatic event following the Triassic collision between the North and South China blocks in China. Therefore, the Triassic plutons in the Hongseong area offer an important insight into the Triassic geodynamic history of the NE Asian region.