• Journal of Korean Society of Forest Science
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• v.86 no.1
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• pp.69-79
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• 1997

The purpose of this study is to acquire essential data to reduce the amount of woody debris resulted from the debris flow. This research examined topographic characteristics of the channelbed affecting generation, movement and storage of woody debris and woody characteristics related to number, sizes, shapes, decay, storage direction to mountainous stream. 1. The number of woody debris had a tendency to increase in proportion to stream width, but it was hardly affected by longitudinal gradient of stream. Especially, the greater amount of woody debris was stored at wide section of the stream with compound channel, and it was found in deposits of channelbed rather than in the present channel. 2. Total woody debris over 10cm in diameter and over 2m in length was 402 units and storage number was 35.3 units per 100m of stream. Average diameter of breast height and length were 14cm and 4m, respectively. The woody debris appeared shorter in length and greater in diameter at down-stream than up-stream. 3. Since woody debris met sediments and bed-materials of great roughness in moving, the greater amount of woody debris without root was found in up-stream and down-stream, but deformed woody debris was discovered in upper stream. Decay of woody debris was more severe in down-stream and woody debris on rotting process was found down-stream. 4. Storage direction of woody debris was mainly parallel to center line of stream, and rate of parallel and perpendicularity was 276 and 126 units, respectively. But, as woody debris storing to the perpendicular direction was unstable, the traveling debris could easily be stored. Therefore, some counterplan was required to prevent the traveling woody debris. 5. Tree species of woody debris was mainly larch, which occupied about two third of total woody debris(256 units). The woody debris of larch is easy to move due to hitting of channelbed materials or lower channelbed fluctuation because the lower part of larch is weaker than its upper part. Therefore, the section of the tree species planting in the riparian vegetation needs much more carefulness.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.4
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• pp.295-302
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• 2014

This study demonstrates a double-path CDI as an alternative of advanced wastewater treatment process. While the CDI typically consists of many pairs of electrodes connected in parallel, the new double-path CDI is designed to have series flow path by dividing the module into two stages. The CFD model showed that the double-path had uniform flow distribution with higher velocity and less dead zone compared with the single-path. However, the double-path was predicted to have higher pressure drop(0.7 bar) compared the single-path (0.4 bar). From the unit cell test, the highest TDS removal efficiencies of single- and double-path were up to 88% and 91%, respectively. The rate of increase in pressure drop with an increase of flow rate was higher in double-path than single-path. At 70 mL/min of flow rate, the pressure drop of double-path was 1.67 bar, which was two times higher than single-path. When the electrode spacing was increased from 100 to $200{\mu}m$, the pressure drop of double-path decreased from 1.67 to 0.87 bar, while there was little difference in TDS removal. When proto type double-path CDI was operated using sewage water, TDS, $NH_4{^+}$-N, $NO_3{^-}$-N and $PO_4{^{3-}}$-P removal efficiencies were up to 78%, 50%, 93% and 50%, respectively.

• The Korean Journal of Petroleum Geology
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• v.5 no.1_2 s.6
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• pp.9-15
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• 1997

The study area is located in the Central Bransfield Basin, Antarctica. To analyze the morphology of seafloor, structure of basement, and seismic stratigraphy of the sedimentary layers, we have acquired, processed, and interpreted the multi-channel seismic data. The northwest-southeastern back-arc extension dramatically changes seafloor morphology, volcanic and fault distribution, and basin structure along the spreading ridges. The northern continental shelf shows a narrow, steep topography. In contrast, the continental shelf or slope in the south, which is connected to the Antarctic Peninsula, has a gentle gradient. Volcanic activities resulted in the formation of large volcanos and basement highs near the spreading center, and small-scale volcanic diapirs on the shelf. A very long, continuous normal fault characterizes the northern shelf, whereas several basinward synthetic faults probably detach into the master fault in the south. Four transfer faults, the northwest-southeastern deep-parallel structures, controlled the complex distributions of the volcanos, normal faults, depocenters, and possibly hydrocarbon provinces in the study area. They have also deformed the basement structure and depositional pattern. Even though the Bransfield Basin was believed to be formed in the Late Cenozoic (about 4 Ma), the hydrocarbon potential may be very high due to thick sediment accumulation, high organic contents, high heat flow resulted from the active tectonics, and adequate traps.