• The Korean Journal of Quaternary Research
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• v.15 no.1
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• pp.29-35
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• 2001

The coastal deposits along Moonamni, Kangwon Province, Korea have been investigated by using deeply cored sediments(down to the basement rocks : Pre-Cambrian metamorphic rocks and granitic rocks) in order to understand and propose the late Quaternary stratigraphy and related major unconformities. Three major stratigraphic -depositional units are proposed. The neolithic cultural sites in the Moonamni area are considered as middle Holocene coastal dunes, which were developed due to active supply of beach sands from Unit I(Holocene transgressive deposit). Such coastal dune sediments are characteristic in the upper part of Unit I(Holocene in age). So far, Unit II and Unit III are considered as continental deposits, such as fluvial-swamp and alluvial deposit, respectively.

• The Korean Journal of Malacology
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• v.24 no.1
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• pp.41-50
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• 2008

The histochemical characteristics and ultrastructure of the mantle in the spiny top shell, Batillus cornutus were described using light and electron microscopy. The simple epidermal layer wrapped on the top and bottom of the centrally located connective tissue. And then the epidermal layer were divided into the outer epidermal layer near a shell and the inner epidermal layer closed to the visceral mass. The connective tissue layer was composed of the collagen fiber muscularfiber bundle and hemolymph sinus. Mucous cells in the apical mantle contained acid and neutral mucopolysaccaride, and acidic carboxylated mucopolysaccaride in the mid and marginal mantle. The mantle thickness, epidermal layer thickness and hemolymph sinus area displayed a trend of reduction from the marginal zone to the apical zone. From TEM observation, it was possible to distinguish epithelium, ciliated cell, absorptive cell and secretory cell in the epidermal layer. The epithelia were columnar and the nucleus was elliptical. The free surface were covered with microvilli. The lateral membranes of epithelium was con nected with neighboring cells by the zonular occludens, zonular adherens and membrane interdigitation. Ciliated cell on free surface had cilia and microvilli, and numerous mitochondria in the apical cytoplasm. In the epidermal layer, it observed 2 type cells having absorptive function. The absorptive cells were columnar in shape, and contained microvilli, pinocytotic vesicles, mitochondria and lysosomes of various electron density. Secretory cells can be divided into four types (A, B, C, D) depending on the cell shape and characteristics of secretory granules. These cells were unicellular glands and had similar characteristics to previously reported on the mantle of the gastropod and bivalves.

• The Korean Journal of Malacology
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• v.24 no.3
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• pp.229-241
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• 2008

Changes of growth and histopathological feature in the mantle structure of the equilateral venus, Gomphina veneriformis exposed to tribultyltin chloride (TBTCl) for 36 weeks were observed. Concentrations of TBTCl were 0, 0.4, 0.6, and $0.8{\mu}g/L$. A regression analysis by power function of SPSS was shown that the growth of experimental groups was significantly decreased after 12 weeks of exposure. For histological analysis, mantle tissues were characterized using H-E stain, AB-PAS (pH 2.5) reaction and Masson's trichrome stain, and epidermal layer thickness and mucous cell distribution were analysed using the image analyser. The mantle had 4-folds (inner-inner, inner-outer, middle, and outer) and its epidermal layer consisted of simple epithlia. A periostracum was observed in the periostracal groove between middle and outer fold. Inner epidermal layer consisted of simple ciliated columnar epithelia, but the outer epidermal layer consisted of simple non-ciliated columnar epithelia. Alcian blue positive mucous cells showed blue color (7462c, 653c) in the inner fold, violet color (2583c) in the middle fold, and blue color (647c, 7455c) in inner epidermal layer (numbers in the parenthesis are codes of Pantone process coated color). Hemolymph sinus in the mantle was extended, and mucous cells in inner plica of the middle fold were stained as blue (7455c) and violet (2587c), after 12 weeks of TBTCI exposure. Cilia and striated border were disappeared, and number of mucous cells in the inner epidermal layer was reduced. Serious histopathological changes in middle and outer fold near the periostracum were observed after 36 weeks. Moreover, epidermal layer thickness and mucous cell distribution were showed decreasing tendency as exposure time to TBTCI was increased. Results of this study suggested that TBTCl induced growth disorder with histopathological changes.

• Korean Journal of Ichthyology
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• v.26 no.1
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• pp.25-33
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• 2014

This study was conducted to observe the spawning behavior and early life histroy of elegant blenny, Omobranchus elegans reared in the laboratory. The elegant blenny were caught at Dolsan lsland, Yeosu-si, Jeollanamdo from June in 2012. As a result of observeation, male fish attracted female continuously and guide lead to spawning site and clean the surface of inner pant in oyster shell or barnacle shell. Female left after spawning and male protected their eggs until they had hatched out. The fertilized eggs were spherical in shape (mean diameter: 1.06 mm; mean oil globule diameter: 0.24 mm) and transparent. Larvae hatched at 203 hrs 40 mins after fertilization at $25.5{\sim}28.5^{\circ}C$ (mean $27.0^{\circ}C$). The newly hatched larvae were 3.04~3.09mm(mean 3.06 mm, n=10) in total length and their mouth and anus were already opened. They began to eat rotifer and transformed to postarvae stage. 10 days after hatching postlarvae was measured 6.39~6.45mm(mean 6.42 mm, n=10) in total length. 60 days after hatching juvenile was measured 21.5~22.2 mm (mean 21.8 mm, n=10) in total length with dosal fin rays XI-22; ventral fin rays I-2; anal fin rays II-23; caudal fin rays 21; pectoral fin rays 13.

• Geophysics and Geophysical Exploration
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• v.8 no.4
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• pp.243-250
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• 2005

Analysis of high-resolution seismic profiles acquired from the inner shelf off the southern coast of Korea reveals that the inner shelf sequence can be divided into three stratigraphic units formed after the Last Glacial Maximum (LGM). Unit I is characterized by complex seismic facies including semi-transparent, stratified, and hummocky reflections on seismic records. It consists of sandy mud or muddy sand, deposited under estuarine environment during the post-glacial transgression. Unit II acoustically shows semi-transparent or hummocky reflections and consists of sand with gravels and shell debris, produced by shoreface erosion during the transgression. Unit III is characterized by transparent or semi-transparent seismic facies and consists of mud originated from the Nakdong and Seomjin rivers during recent highstand of sea level. Unit III is confined to the inner shelf with an extenal form of stratal wedge.

• Journal of the Korea institute for structural maintenance and inspection
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• v.15 no.5
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• pp.169-177
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• 2011

In this study, an impact resistance of concrete segmented composites adopted shell's structures which have the excellent impact resistance was assessed. In order to enhance the performances of concrete segmented composite, the bond strength of mortar between the concrete blocks should be improved. Hence, in this study polymer mortars were applied to increase the bond strength of mortar. From the results of bond tests, the 15% latex mortar was selected and static and low-velocity impact tests were carried out for the specimens applied the plain and latex mortar. The concrete segmented composites, of which the bond strength of mortar was enhanced, showed improved low-velocity impact resistances. A Nonlinear finite element analysis using the discrete crack model showed similar energy dissipating capacities to the impact test's results. Consequently, by improving the analysis models for segmented composites, the impact resistances for manifold variables can be predicted and assessed.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.5
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• pp.609-621
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• 1998

Sand ridges in the South Sea of Korea have been investigated to reveal the surface morphology and vortical variation in sediment physical property. Both field and laboratory methods such as high resolution subbottom profiling, side scan sonar, and physical property and sediment textural study on cored sediments were employed. Asymmetric sand waves are found on the ridge, No prominent difference in the sediment was recorded throughout the ridge area. Sediment sorting is generally poor due to interbedded mud. Average compressional wave velocity is 1753 m/sec for the sand dominated core section, Most of cores show two prominent facies: facies A and B. Facies A is defined as modern mud sediment and B is dominated by relict sand. Facies B is characterized by gravel, sand, and shell fragment, It is suggested that the facies B was developed in transgressive environment by tide and sporadic high energy events.

• Journal of Conservation Science
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• v.30 no.4
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• pp.457-466
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• 2014

Rigorous analysis was performed to identify the structure and materials of the murals to study techniques used on mural tombs of ancient Daegaya era(6th century). The murals were painted by applying mortar on the walls and the ceiling after building a stone chamber and creating ground layers on mortar layers. Mud was applied on most of the mortar layers on four sides of the walls except the ceiling. Sand was not used in mortar but was made of materials with pure calcium substances. In addition, shells in irregular sizes with incomplete calcination were mixed; and the mortar's white powder was inferred as lime obtained by calcination of oyster shells. Kaolinite($Al_2Si_2O_5(OH)_4$) was used in the ground layer, Cinnabar(HgS) was used for red pigment, Malachite($Cu_2CO_3(OH)_2$) for green and Lead white($PbCO_3{\cdot}Pb(OH)_2$) for white. Mud plaster was applied on the mortar and was composed thinly and densely using clayey of particle size smaller than that of medium sand. It was assumed that the finishing was for repair after long time had passed since the mortar layer came off. Using lime made with oyster shells as mortar is unprecedented in ancient Korean mural tombs and its durability was very poor, suggesting that Gaya's mortar production technique was relatively behind compared to that of Koguryo's in the same era.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.1 no.2
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• pp.59-72
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• 1996

The stratigraphy of the Gomso-Bay tidal flat consists of basement, preHolocene oxidized unit, and Holocene tidal sequence in ascending order. The oxidized unit is a yellowish brown stiff mud of the last stadial (or subglacial) stage before 12,000 yr B.P. This yellowish brown preHolocene unit does not contain any marine fossils, but contains plant roots, plant fragments, and also vertical and horizontal microfractures indicating soil-formation when exposed. It is regarded as interfluve deposits. The Holocene tidal sequence is composed of lower mud facies (upper-flat muds), upper sand and muddy sand facies (middle to lower-flat sands). This coarsening-upward and retrograding pattern of Holocene tidal deposits reflects a Holocene sea-level rise. The plots of $\^$14/C-age versus depth of dated samples (peats and shells) show that the sea level of 7,000 yr B.P. was located about 6.5 m below the present mean sea level, and the sea levels of 4,000 yr B.P. and 2,000 yr B.P. were also situated about 3 m and 2.5 m below the present mean sea level, respectively.

• Korean Journal of Soil Science and Fertilizer
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• v.22 no.3
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• pp.173-179
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• 1989

Characterization and classification of the potential acid sulfate soils found on flood-plains in Yeongnam area were summarized as follows: 1. The "Potential acid sulfate soil" layer(s) were appeared in the around 2-4m substrata of soil profiles and characterized by the fine texture, high reduction and physical unripened soft mud deposits or having higher contents of organic matter with dark color. 2. The contents of total sulfur (T-S) in those soils were ranged around 0.45-0.9% and the materials exhibited a strong acidity upon the oxidation with $H_2O_2$. Although the T-S contents was low as much as 0.15%, the sulfidic materials were also acidified strongly by the oxidation with $H_2O_2$ in the condition of lower content of carbonates. As defined in Soil Taxonomy of USDA, most of the sulfidic materials contained less than 3 times carbonate ($CaCO_3$ equivalent wt. %), but there were some which abundant in shell fragments, contained more than 3 times carbonate by weight percentage and that not much acidified by the oxidation with $H_2O_2$. 3. The contents of T-S correlated negatively with the pH oxidized by $H_2O_2$ and with the fizzing time (minutes) due to addition of $H_2O_2$. 4. The potential acid sulfate soils could be defined as soil materials that had sulfidic layer(s) more than 20cm thick within 4m of the soil profile and contained more than 0.15% of T-S with less than 3 times carbonate ($CaCO_3$ equiv. %). A tentative interpretative soil classification system was proposed, i.e., "Weak potential acid sulfate (T-S, 0.15-0.5%)", "Moderate potential acid sulfate (T-S, 0.5-0.75%)", and "Strong potential acid sulfate (T-S, more than 0.75%)". Finally, it was proposed that the "Detailed soil survey with high intensity" should be carried out in the areas of agricultural engineering works such as arableland readjustment works, in advance.