• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.9 no.2
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• pp.64-72
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• 2004

We measured the vertical profiles of $O_2$, H$_2$S, and pH in sediment pore water beneath marine cage fish farms using a microsensor with a 25 ${\mu}{\textrm}{m}$ sensor tip size. The sediments are characterized by high organic material load. The oxygen consumption, hydrogen sulfide oxidation, and sulfate reduction rates in the microzonations (derived from the vertical distribution of chemical species concentration) were estimated by adapting a simple one-dimensional diffusion-reaction model. The oxygen penetration depth was 0.75 mm. The oxic microzonations were divided into upper and lower layers. Due to hydrogen sulfide oxidation within the oxic zone, the oxygen consumption rate was higher in the lower layer. The total oxygen consumption rate integrated with reaction zone depth was estimated to be 0.092 $\mu$mol $O_2$cm$^{-2}$ hr$^{-1}$ . The total hydrogen sulfide oxidation rate occurring within 0.7 mm thickness was estimated to be 0.030 $\mu$mo1 H$_2$S cm$^{-2}$ hr$^{-1}$ , and its turnover time in the oxic sediment layer was estimated to be about 2 minutes. This suggests that hydrogen sulfide was oxidized by both chemical and microbial processes in this zone. The molar consumption ratio, calculated to be 0.84, indicates that either other electron accepters exit on hydrogen sulfide oxidation, or elemental sulfur precipitation occurs near the $O_2$- H$_2$S interface. Total sulfate reduction flux was estimated to be 0.029 $\mu$mol cm$^{-2}$ hr$^{-1}$ , which accounted for more than 60% of total $O_2$ consumption flux. This result implied that the degradation of organic matter in the anoxic layer was larger than in the oxic layer.

• Economic and Environmental Geology
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• v.40 no.5
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• pp.537-549
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• 2007

The characteristics of the mineralization and geology in the northern Mt. Taebaek mining district are found to be similar with those reported from Nevada district where the Carlin-type gold deposit occurs characteristically as repeated metallic ore deposits in space and time. Though two spots of hs and several spots of Sb anomalies were recognized in the Yeongweol area, they have no relationship with any metalliferous mineralization. On the other hand, two spots of As anomaly in the Jeongseon area have shown to be related with metalliferous ore deposits (mainly Ag-Au), and they are closely associated with Sb anomaly. Some elements of altered limestones in the study such as Au, Ag, As, Sb, Cu, Pb, Zn, and Mo area are closely associated together, and are more enriched in the Jeongseon area than in the Yeongweol area. In particular, Sb and As which may reflect the occurrence of the Carlin-type gold deposit are highly enriched. However, the base metals such af Zn and Pb are highly variable according to samples. The patterns of the enrichment factor for Sb and As, as well as those for Ag and Au, are very similar with those reported from the Carlin-type gold deposits in Nevada. These similarities in elemental distribution may imply that hydrothermal ore mineralization in the study areas was possibly originated from a fluid with the characteristics of the Carlin-type gold mineralization found in Nevada, China, and Indonesia. However, the pattern of base metals and Mo are different. This may result from different chemistry and/or mineralogy of host rock in the study areas.

• Korean Journal of Heritage: History & Science
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• v.53 no.4
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• pp.100-117
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• 2020

National Treasure no. 101, the stupa of State Preceptor Jigwang from the Beopcheonsa Temple Site in Wonju has been transferred from place to place and reassembled several times since it was built. In particular, overall dismantling and repair was carried out in 1957 to restore parts damaged by bombing during the Korean War. Documented information on the repair process and materials used at that time does not exist. However, various types of metal materials used for this stupa have been identified during conservation work. Besides clamps anchor bolts, 9mm-thick circular rebars were mainly used for joining the parts of this stupa, while circular rebars and wires of various thicknesses were used for joining the parts with mortar restoration materials. Although deformed bars are typically used for stone pagodas classified as architectural structures, smooth circular rebars were used in this case. In terms of restoration using mortar, material shapes were transformed, bound alternately, and twisted irregularly to improve bonding strength and coherence in order to insert restoration materials and to bolster structural weaknesses. In addition, metallographic analysis showed the material to be hypo-eutectoid steel with low carbon content. Many non-metallic inclusions in the shape of drops of different sizes were included, which do not affect the whole elemental composition due to the very small quantities involved. Qualitative and EPMA analysis of Mn and S, which were not identified by SEM-EDS area analysis, established an even distribution of MnS in crystal grains of the microstructure, regardless of the shape of the samples. It is presumed that secondary homogenization and softening might have been conducted after manufacturing to facilitate the working process. Furthermore, in consideration of properties indicating that the thinner the steel is, the less carbon content contained and the greater the elasticity and elongation, it is judged that restoration work was ordered.