• 한국지리정보학회지
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• 제3권1호
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• pp.44-56
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• 2000

Landsat TM 영상을 이용하여 곰소만 간석지의 미지형을 분류하고, 현지조사를 통하여 분류된 각 미지형의 퇴적물 입도 특성과 지형특성을 밝혔다. 내만 쪽의 mud flat는 갯골과 갯골 사이의 평탄지로 이루어져 있으며, 평균입경이 $4{\phi}$ 이하의 세립질이고 분급은 1 S.D. 이상이며, positive skewness를 보인다. 만구쪽에 분포하는 sand flat는 갯골이 없이 평탄한 지형을 이루며 ripple mark가 발달해 있다. 분급이 좋은 모래로 대부분 구성되어 있고 negative skewness를 보인다. mixed flat는 mud flat 와 sand flat와의 중간적 특징을 보인다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 1998년도 Proceedings of International Symposium on Remote Sensing
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• pp.110-115
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• 1998

Through the ISODATA method, the micro-landform of Julpo-Bay tidal flat was classified into mudflat, mixedflat, and sandflat using Landsat TM image. Each showed an apparent differences in its topographical characteristics and grain size composition. For example, mudflats are formed with flat faces and tidal channel of dissected gully. Its characteristics of grain size analysis that the grains have less than mean grain size 4 phi. Its sorting is bad (higher than 1 S.D.), and it showed strongly positive skewness. But sandflat is topographically flat without tidal channel. It has developed with ripple marks. According to the grain size analysis of deposits, the soil is coarse size with 90% of sand and its sorting is well(lower than 1 S.D.) Also, it showed strongly negative skewness. Mixed flat is in between mudflat and sandflat in its characteristics.

• Ocean Science Journal
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• 제42권2호
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• pp.69-79
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• 2007

A vertical transect with 4 km length was established for the macrofaunal survey on the Chokchon macrotidal flat in Kyeonggi Bay, Incheon, Korea, 1994. Tidal elevation (m) and sediment mean grain size $(\phi)$ were inversely predicted by the transfer functions from the faunal assemblages. Three methods: weighted average using optimum value (WA), tolerance weighted version of the weighted average (WAT) and maximum likelihood calibration (MLC) were employed. Estimates of tidal elevation and mean grain size obtained by using the three different methods showed positively corresponding trends with the observations. The estimates of MLC were found to have the minimum value of sum of squares due to errors (SSE). When applied to the previous data $(1990\sim1992)$, each of three inference models exhibited high predictive power. This result implied there are visible relationships between species composition and faunas' critical environmental factors. Although a potential significance of the two major abiotic factors was re-affirmed, a weak tendency of biological interaction was detected from faunal distribution patterns across the flat. In comparison to the spatial and temporal patterns of the estimates, it was suggested that sediment characteristics were the primary factors regulating the distribution of macrofaunal assemblages, rather than tidal elevation, and the species composition may be sensitively determined by minute changes in substratum properties on a tidal flat.

• Journal of the Korean Wood Science and Technology
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• 제29권3호
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• pp.14-20
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• 2001

On the bending process, metal-strap plays an important role in dispersing the stress generated in wood. Therefore, the metal-strap has more influence on the property of bentwood materials. The effect of the metal-strap thickness for bentwood was examined. The effect of metal-strap on the bending properties of Korean red pine(Pinus densiflora Sieb. et Zucc.)was investigated in this research. The metal-strap thickness is divided into 4 kinds such as 1.0, 0.8, 0.6, 0.4 mm. The specimens were selected by grain such as annual ring angles, flat grain and half-edge grain specimens. As a result of this study, the bending ability of 1.0, 0.8 mm, thickness of half-edge grain specimens was better than flat grain specimens but the result of 0.6, 0.4 mm were reversed. The bending ability of half-edge grain was better than flat grain and the grade was higher. When the processed specimens were dried, the radius of curvature(ROC) was decreased became drying-stress was not perfectly dispersed. An optimum drying-condition would deminish this phenomenon.

• 한국제4기학회지
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• 제18권2호통권23호
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• pp.19-22
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• 2004

Seasonal changes of topograpy, sediment grain size and accumulation rate on the Gomso-Bay tidal flat(Fig. 1), west coast of Korea, have studied in order to understand the seasonal accumulation pattern and preservation potential of tidal-flat sediments. Seasonal levelings across the tidal flat show that the landward movement of both intertidal sand shoals and cheiers accelerates during the winter and typhoon period, but it almost stops in summer when mud deposition is instead predominant on the middle to upper tidal flat. Seasonal variations of mean grain size were largest on the upper part of middle tidal flat where summer mud layers were eroded during the winter and typhoon periods(Fig. 2). Measurements of accululation depths from sea floor to basal plate reveal that accumulation rates were seasonally controlled according to the elevation of tidal-flat surface(Table 1) : the upper flat, where the accumulation rate of summer was generally higher than that of winter, was characterized by a continuous deposition throughout the entire year, whereas on the middle flat, sediment accumulations were concentrated in winter realtive to summer, and were intermittently eroded by typhoons. The lower tidal flat were deposited mostly in winter and eroded during summer typhoons. Cancores taken across the tidal flat reveal that sand-mud interlaers resulting from such seasonal changes of energy regime are preserved only in the upper part of the deposits and generally replaced by storm layers downcore(Fig. 3). Based on above results, it is suggested that the storm deposits formed by winter stors and typhoons would consist of the major part of the Gomso-Bay deposits(Fig. 4).

• 자동차안전학회지
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• 제13권3호
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• pp.20-25
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• 2021

Flexural resistance evaluation of FFC (Flexible Flat Cable) was performed according to the grain size of rolled copper foil by adding 0.1wt% silver (Ag) and electrodeposited copper foil by slitting method after heat-treatment. These methods are aimed at enhancing the flexural durability of the FFC by growing the grain size of copper foil. By increasing the grain size of the copper foil and minimizing the miss-orientation at grain boundaries, the residual stress at the grain boundaries of the copper foil is reduced and the durability of the FFC is improved. Maximizing an average grain size of copper foil can be got a good solution in order to enhance the durability of the FFC or FPCB (Flexible Printed Circuit Board).

• 환경영향평가
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• 제11권4호
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• pp.247-258
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• 2002

This study aimed at verifying the grain-sized distribution of surface deposits in a tidal flat using multi-spectral Landsat TM. In this study, we employed the grain-sized analysis, PCA and unsupervised classification techniques for analyzing the distribution of deposits. As a result in this study, the unsupervised classification method using PCA image was found to be most useful in classifying tidal flat deposits using satellite data. This method is considerably effective in analyzing not only the aspects of distribution in terms of accumulated deposits and erosion, but also the changes in seaside topography and shoreline. The grain-sized distribution analysis indicates that the mud flat inside the Cheonsu-bay tidal flat is distributed, the mixed flat located in the middle, and the sand flat distributed near the sea. The sand flat is dominant around the southern part of Seomot isle and its beach. On the other hand, the mud and mixed flat is dominant on the western part. Likewise, the western coast of Seomot isle and its beach is significantly affected by waves facing the offshore. However, the eastern side of the bay could be a site for the evolution of tidal flat made of fine materials where it is less affected by ocean waves. These results show that multi-spectral satellite data are effective for the classification of distribution materials and environmental impact assessment and continuous monitoring. In particular, the research on environmental deposits can provide important decision-supporting information for decision-making on seaside development, by analyzing the progress of deposits and environmental changes.

• 대한원격탐사학회지
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• 제19권2호
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• pp.117-133
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• 2003

이 연구에서는 곰소만 조간대에서 현장 시료채취와 동시에 얻어진 Landsat ETM+ 자료를 이용하여 조간대 환경요인들이 ETM+에 의해 관측된 반사도와 어떤 관계를 가지고 있는 지 밝히고, 광학위성영상을 이용한 조간대 표층퇴적물의 분류의 적용 가능한 기준입도를 제시하고자 하였다. 일반적인 퇴적학적 분류 기준이 되는 4 $\Phi$ 입도를 기준으로 했을 때 입도와 영상의 반사도 간의 상관관계는 매우 낮은 것으로 나타났으나, 2 $\Phi$ 이상의 입자를 기준으로 하였을 때는 상부조간대의 천주변에 작은 입자로 구성된 지역의 자료들을 제외하면 ETM+ 밴드 4번과 0.699의 높은 상관계수를 보인다. 즉, 입도 2 $\Phi$ 곰소만 조간대에서의 광학위성 자료에 의한 표층퇴적물 분류를 위한 기준입도로 사용하는 것이 타당하다. 입도와 함수율은 비교적 높은 음의 상관관계를 보이며 특히 입도 2 $\Phi$ 기준과는 -0.811로서 뚜렷하게 음의 상관관계를 보인다 위성자료의 Factor analysis 결과는 지형요소에 의해 크게 영향을 받는 독일의 조간대와는 다른 특성을 보이며, 이는 곰소만의 경우는 입자가 세립하여 지형보다는 함수율에 더 큰 영향을 받는 것으로 나타났다. 결국 조간대 원격탐사에서는 입도뿐만 아니라 함수율과 지형 등의 환경요소가 함께 고려하여야만 한다.

• 한국가구학회지
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• 제21권2호
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• pp.188-195
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• 2010

This study has been focused on the evaluation of domestic softwood timbers to replace imported timbers for woodcrafts and furniture-making. Figures on radial and tangential sections were observed with naked eyes. As the result of study on the figures appeared on the wood surface of 6 species of trees, flat grain and edge grain were clearly found from Taxus cuspidata. Juniperus chinensis and Ginkgo biloba had wavy grain figure and pigment figure, and blister figure was found in Pinus densiflora, Larix kaempferi showed pitch streak and irregular figures on its tangential section due to growth abnormalities. Wavy grain figure appeared weakly on near knot of Pinus koraiensis. The characteristic figures shown from each species of trees are expected to be used for crafts, sculptures, furniture, and interior decoration. They are also considered to have great potential to substitute imported timber sufficiently, which are currently used a lot for wood crafts and furniture-making.

• 한국지형학회지
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• 제25권1호
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• pp.31-45
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• 2018

This study investigated the characteristics of sedimentary environment changes across a tidal flat in Gagyeongju of Anmyeondo Island. We performed a spatio-temporal analysis on the grain sizes composition of sediments and micro-landform changes during the winter from 2013 to 2016. The results showed that erosion was a dominant processthroughout the study flat, reducing the surface elevation even by 1 m around the upper sand flat. As a consequence, headlands have formed in the entire region of Gagyeongju village. In addition, erosion quickly progressed along the low-lying subtidal zone and tide way and, in contrast, sedimentation progressed in the mid-elevation tidal flat. We posit that a jetty, which had been constructed as a pier facility on the eastern part of the study area, interfered with the flow of tidal current, thereby enhancing these erosional processes. This is because such interference can block the supply of fine-textured sediments from the nearby Cheonsu Bay and therefore reduce surface elevation. According to the surface sediment analysis, the sediments were categorized into 7 sedimentary facies, and generally displayed a high ratio of silt and clay. The result of time-series analysis (2012-2013) showed that the sediments on the tidal flat became fine-grained, and that sorting became worse. However, the sediments on the subtidal zone, embayment and along inside of the jetty tended to be coarse-grained. In conclusion, the tidal flat microlandform change in the study area was caused by a disruption in the seawater circulation due to the jittery construction within the tidal flat, which had a direct effect on erosional and sedimentary environment processes.