• The Journal of Natural Sciences
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• v.6 no.1
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• pp.5-39
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• 1993

The Blue-green algae collected from whole coasts of Korea were investigated morphotaxonomically in order to list up Korean marine Cyanophyta and clarify their taxnomic position. As a result, 36 species, 20 genus, 6 families belonging to 3 orders were identified. Among these, 14 species were recorded for the first time in Korea. They are Chroococcus minutus (K$\"{u}$tzing) N$\"{a}$geli, Merismopedia punctata Meyen, Microcystis ichtyoblabe K$\"{u}$zing, Dermocarpa leibleiniae (Reinsch) Born. et Thur., Hydrocoleum confluens (Setchell et Gardner) Drouet, Lyngbya sordida (Zanard.) Gomont, Phormidium forveolarum (Mont.) Gomont, Phormidium hansgieri Schmidle, Skujaella hildebrandtii (Gomont.) de Toni, Sphaeronema lithophila (Ercegovic) Umezaki, Spirulina tenerrima K$\"{u}$tzing, Hormothamnion enteromorphoides Grunow, Michrochaete aeruginea Batters, Michrochaete grisea Thuret ex Born. et flah.. Using the phase contrast microscope and the Nomarski interference micrope, we made photomicrographs of minute blue green algae. The cellular inclusions especially PHB(poly-$\SS$-hydroxy-butyrate) granules of the blue-green algae identified were investigated. The species clearly characteriged to have PHB granule were Lyngbya confervoides, L. semiplena, Phormidium corium, Sirocoleum kurzii, Hormothamnion enteromorphoides and Calothrix crustacea. These result would be fundamental data for estabilishing phylogenetic system of blue-green algae based on physio-biochemical characteristics in future.

• The Journal of the Petrological Society of Korea
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• v.18 no.4
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• pp.315-336
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• 2009

We have studied the orientational characteristics of microcrack frequency, it's length and density in Tertiary crystalline tuff from the northeastern part of the Gyeongsang Basin. 134 sets of microcracks on horizontal surfaces of 3 rock samples from Heunghae-eup were distinguished by enlarged photomicrographs of the thin sections. The variability in patterns among microcrack length-frequency histograms for three rock samples from different altitudes were derived. The pattern of histograms changes progressively from negative exponential form to log-normal form in proportion to altitude. The distribution pattern for rock sample no.1 from lower altitude shows the broad length distribution characterized by higher mean and median, and higher standard deviation. Meanwhile, this distribution pattern corresponds with characteristics of joint length distribution in sedimentary rocks of the lower part of the Gyeongsang Supergroup. The occurrence frequency of shorter microcracks increases toward both NW and NE directions from the $N0{\sim}10^{\circ}W$, with the dominant direction of $N80{\sim}90^{\circ}W$ and $N80{\sim}90^{\circ}E$, respectively. This distribution pattern represents the relative differences in formation timing among microcrack sets and the result of the new initiation of shorter microcracks. Meanwhile, the longest microcracks within $N60{\sim}70^{\circ}W$($L_{max}$:1.18 mm) and $N0{\sim}10^{\circ}W$($L_{max}$:0.80 mm) directions are seen, but this kind of microcracks are very limited in number. Whole domain of the directional angle($\theta$)-frequency(N), length(L) and density($\rho$) chart can be divided into five sections in terms of phases of the distribution of related curves. From the distribution chart, density curve shows five distinct peaks in the WNW-ESE($N70{\sim}80^{\circ}W$), NS~NNE-SSW($N0{\sim}10^{\circ}W$, $N10{\sim}20^{\circ}E$), ENE-WSW($N50{\sim}60^{\circ}E$), and nearly EW($N80{\sim}90^{\circ}E$) directions, respectively. Especially, main directions of faults correspond with the directional angle showing high density. Consequently, these distribution patterns of density curve reflect the representative maximum principal stress orientations suggested in previous studies.

• The Journal of Korean Academy of Prosthodontics
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• v.49 no.1
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• pp.57-64
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• 2011

Purpose: The purpose of this study was to compare the cleansing performance of a distilled water, a diluted solution of sodium hypochlorite as a household bleaching cleanser and three alkaline peroxide cleansers in vivo plaque deposits by using scanning electron microscope. Materials and methods: Five individuals were selected from department of the prosthodontics in Pusan National University Hospital, and each of them was inserted with specimens for plaque accumulation in their temporary dentures for 48 hours. The specimens were removed and cleaned by each cleansing agents for 8 hours. Scanning electron micrographs were made from the specimens at a magnification of ${\times}2,000$. A panel of ten persons with a dental or paradental background, but not directly involved in the study, was selected to analyze the photomicrographs to determine which denture cleanser was more effective in removing plaque. Results: Diluted solution of sodium hypochlorite was the most effective at removing plaque following $Polident^{(R)}$, $Cleadent^{(R)}e$, $Bonyplus^{(R)}$ and distilled water in order. But there was no significant difference of cleansing efficacy between diluted solution of sodium hypochlorite and $Polident^{(R)}$, $Polident^{(R)}$ and $Cleadent^{(R)}e$, $Cleadent^{(R)}e$ and $Bonyplus^{(R)}$, respectively (P > .05). Alkaline peroxide cleansers by themselves cannot adequately remove accumulated plaque deposits, especially if the deposits are heavy. Corrosion could be seen on the surface of non-precious alloy specimens immersed in diluted solution of sodium hypochlorite. Conclusion: It is recommended to use of alkaline peroxide type cleansers with brushing whenever possible, since denture cleanliness is often poor due to the relative inefficiency of these cleansers.

• The Journal of the Petrological Society of Korea
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• v.7 no.2
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• pp.132-145
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• 1998

The coal-bearing siliciclastic rocks of the Lower Permian Jangseong Formation, Samcheog coalfield, represent a megacyclothem which shows cyclic repetitions of sandstone, shale, coaly shale, and coals. Petrographic, geochemical, and SEM studies for sandstone samples, and XRD analysis for clay minerals were carried out to understand diagenesis in the sandstones of the Jangseong Formation. The Jangseong sandstones are composed of 60% quartz (mainly monocrystalline quartz) and 36% clay matrix and cement with minor amounts of feldspar, lithic fragments and accessory minerals (less than 4%). Jangseong sandstones are classified mostly as quartzwackes and partly as lithic graywackes according to the scheme of Dott(1964). The textural relationships between authigenic minerals and cements in thin sections and SEM photomicrographs suggest the paragenetic sequence as follows; (1) mechanical compaction, (2) cementation by quartz overgrowth, (3) formation of authigenic clay minerals (illite, kaolinite), (4) dissolution of framework grains and development of secondary porosity, and (5) later-stage pore-filling by pyrophyllite. We propose that these diagenetic processes might be due to organic-inorganic interaction between the dominant framework grains and the formation water. The Al, Si ions and organic acid, derived from dewatering of interbedded organic-rich shale and coals, were transported into the Jangseong sandstones. This caused changes in the chemistry of the formation water of the sandstones, and resulted in overgrowth of quartz and precipitation of authigenic clay minerals of kaolinite and illite. The secondary pores, produced during dissolution of clay and framework grains by organic acid and $CO_2$ gas, were conduit for silica-rich solution into the Jangseong sandstones and the influx of silica-rich solution produced the late-stage pyrophyllite after the expanse of kaolinite. The origin of the solution that formed pyrophyllite is not likely to be the organic-rich formation water based on the observation of fracture-filling pyrophyllite in the Jangseong sandstones, but the process of pyrophyllite pore-filling was indirectly related to organic-inorganic interaction.

• Journal of Life Science
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• v.25 no.12
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• pp.1408-1414
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• 2015

In this study, to retain a stable bacterial inoculant, Bacillus strains showing antifungal activity were screened. The improved production, antifungal mechanism, and stability of the antifungal metabolite by a selected strain, AF4, a potent antagonist against phytopathogenic Botrytis cinerea, were also investigated. The AF4 strain was isolated from rhizospheric soil of hot pepper and identified as Bacillus subtilis by phenotypic characters and 16S rRNA gene analysis. Strain AF4 did not produce antifungal activity in the absence of a nitrogen source and produced antifungal activity at a broad range of temperatures (25-40℃) and pH (7-10). Optimal carbon and nitrogen sources for the production of antifungal activity were glycerol and casein, respectively. Under improved conditions, the maximum antifungal activity was 140±3 AU/ml, which was higher than in the basal medium. Photomicrographs of strain AF4-treated B. cinerea showed morphological abnormalities of fungal mycelia, demonstrating the role of the antifungal metabolite. The B. subtilis AF4 culture exhibited broad antifungal activity against several phytopathogenic fungi. The antifungal activity was heat-, pH-, solvent-, and protease-stable, indicating its nonproteinous nature. These results suggest that B. subtilis AF4 is a potential candidate for the control of phytopathogenic fungi-derived plant diseases.

• The Journal of the Petrological Society of Korea
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• v.26 no.1
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• pp.45-54
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• 2017

The characteristics of the rock cleavage in Jurassic Geochang granite were analysed using the distribution of microcrack lengths and spacings. The phases of distribution of the above lengths and spacings were derived from the enlarged photomicrographs(${\times}6.7$) of the thin section. First, the length and spacing-cumulative diagrams for the six directions of rock cleavages were arranged in increasing order($H2{\rightarrow}R1$) on the density(${\rho}$) of microcrack length. The various parameters were extracted through the combination of the above two types of diagrams. The discrimination factors representing the three quarrying planes and three rock cleavages were acquired through the mutual contrast between the values of parameters. The analysis results of the research are summarized as follows. The evaluation for the six directions of rock cleavages was performed using the parameters such as (1) intersection angle(${\alpha}-{\beta}$) and (2) exponent difference(${\lambda}_S-{\lambda}_L$) between two exponential straight lines related to spacing(${\alpha}$, ${\lambda}_S$) and length(${\beta}$, ${\lambda}_L$). The values of parameters(1 and 2) are in order of H(hardway, (H1 + H2)/2) < G(grain, (G1 + G2)/2) < R(rift, (R1 + R2)/2). On the contrary, the values of the above two parameters for three planes are in order of R < G < H. Meanwhile, the direction of convergence between two exponential straight lines was derived. The above direction is compliant to arrangement of the line os' centering around the line ol. The above two lines converge in the direction of the Y-axis when the line ol and line os' occupy the upper region on the left and the lower region on the right, respectively(R-type). On the contrary, the above two lines converge in the direction of the X-axis when the order of arrangement between line ol and line os' is reversed(H-type). Especially, the positive(+) or negative(-) value of intersection angle(${\alpha}-{\beta}$) is determined by the arrangement of two vertical lines. This type of correlation analysis is useful for evaluating the relative strength of rock cleavage and discriminating three quarrying planes.

• The Journal of the Petrological Society of Korea
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• v.26 no.3
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• pp.297-309
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• 2017

Jurassic granite from Geochang was analysed with respect to the characteristics of the rock cleavage. The comprehensive evaluation for rock cleavages was performed through the combination of the 16 parameters derived from the enlarged photomicrographs of the thin section and the spacing-cumulative frequency diagrams. The results of analysis for the representative values of these spacing parameters with respect to the rock cleavage are summarized as follows. First, the above parameters can be classified into group I (spacing frequency (N), total spacing ($1m{\geq}$), constant (a), exponent (${\lambda}$), slope of exponential straight line (${\theta}$), length of line (oa') and trigonometric ratios ($sin{\theta}$, $tan{\theta}$) and group II (mean spacing (Sm), difference value between mean spacing and median spacing (Sm-Sme), density (${\rho}$), lengths of lines (oa and aa'), area of a right-angled triangle (${\Delta}oaa^{\prime}$) and trigonometric ratio($cos{\theta}$). The values of the 8 parameters belonging to group I show an order of H(hardway, H1+H2)

• The Journal of the Petrological Society of Korea
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• v.24 no.3
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• pp.165-180
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• 2015

Jurassic granite from Geochang was analysed with respect to the characteristics of the rock cleavage. The phases of distribution of microcracks were well evidenced from the enlarged photomicrographs(${\times}6.7$) of the thin section. In this study, the length - cumulative frequency diagrams were used for expressing the distribution characteristics of microcrack. The diagrams for the six directions were arranged in the magnitude of density(${\rho}$). These diagrams show an order of H2 < H1 < G2 < G1 < R2 < R1 from the related chart. Among six diagrams, the diagram for hardway 2(H2) occupies the lowermost region on the left. On the contrary, the diagram for rift 1(R1) occupies the uppermost region on the right. Curve patterns of the two diagrams change from uniform to exponential distribution type in accordance with the increased density. The overall distribution characteristics of the diagrams were well evidenced from the magnitude of the exponent(${\lambda}$) and length of line oa related to the exponential straight line. The magnitude of exponent governing the values of slope(${\theta}$) is inversely proportional to the values of microcrack parameters such as number(N), length(L) and density. On the contrary, length of line oa is directly proportional to the values of the above three parameters. Above microcrack parameters related to the order of arrangement of diagrams show an order of hardway(H1 + H2) < grain(G1 + G2) < rift(R1 + R2). The distribution characteristics of progressive variation are found among the six diagrams. The order of arrangement of the diagrams indicates a relative magnitude of the rock cleavage. Meanwhile, the parameters such as slope, exponent, density and length of line oa were arranged in an order of H2 < H1 < G2 < G1 < R2 < R1. The variation curves of a smooth quadratic function are shown from the related chart. From the correlation chart between density and the above parameters, a common regularity following power-law correlation function was derived. Finally, the analysis for the rock cleavage was conducted through the combination between the diagram and microcrack parameter. This type of combination contribute to the progressivity in evaluation for the rock cleavage.

• The Journal of the Petrological Society of Korea
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• v.25 no.1
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• pp.13-27
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• 2016

The characteristics of the rock cleavage inherent in Jurassic granite from Geochang were analysed. The phases of distribution of microcrack spacings were derived from the enlarged photomicrographs(${\times}6.7$) of the thin section. The evaluation for the six directions of rock cleavages was performed using nine parameters such as (1) frequency of microcrack spacing(N), (2) frequency ratio(${\leq}1mm$ and 4 mm >) to total spacing frequency(N:191), (3) spacing ratio(${\leq}1mm$) to total spacing(118.49 mm), (4) mean spacing($S_{mean}$), (5) difference value($S_{mean}-S_{median}$) between mean spacing and median spacing($S_{median}$), (6) density of spacing, (7) median spacing, (8) reduction ratio of spacing frequency to length frequency and (9) magnitude of exponent(${\lambda}$ and b) related to the distribution type of diagram. Especially the close dependence between the above spacing parameters and the parameters from the spacing-cumulative frequency diagrams was derived. The results of correlation analysis between the values of parameters for three rock cleavages and those for three planes are as follows. The values of (I) parameters(1, 2 and 3), (II) parameters(4, 5 and 6), (III) parameter(7), (IV) parameter(8) and (V) parameter(9) show the various orders of H(hardway, H1+H2) < G(grain, G1+G2) < R(rift, R1+R2), R < G < H, R < H < G, G < H < R and H < G < R, respectively. On the contrary, the values of the above four groups(I~IV) of parameters for three planes show reverse orders. This type of correlation analysis is useful for discriminating three quarrying planes. Six spacing-cumulative frequency diagrams were arranged in increasing order on the value of main parameter($S_{mean}-S_{median}$). These diagrams show an order of R2 < R1 < G2 < G1 < H2 < H1 from the related chart. In other words, the above six diagrams can be summarized in order of rift(R1+R2) < grain(G1+G2) < hardway(H1+H2). These results indicate a relative magnitude of rock cleavage related to microcrack spacing. Especially, the above main parameter could provide advanced information for prediction the order of arrangement among the diagrams.

• The Journal of the Petrological Society of Korea
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• v.26 no.2
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• pp.127-141
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• 2017

Jurassic granite from Geochang was analysed with respect to the characteristics of the rock cleavage. The multicriteria evaluation for the six directions of rock cleavages was performed using the microcrack spacing-related parameters derived from the enlarged photomicrographs (${\times}6.7$) of the thin section and the spacing-cumulative frequency diagrams. The results of analysis for the representative values of these spacing parameters with respect to the rock cleavage are summarized as follows. First, the analysis for deriving the main parameter indicating the order of arrangement among six diagrams was performed. The values of five parameters with respect to six directions of the rock cleavages were arranged in increasing or decreasing order for the above analysis. The decreasing order of the values of main parameter(mean spacing-median spacing, $S_{mean}-S_{median}$) and mean spacing are consistent with the order of H1, H2, G1, G2, R1 and R2 directions. These sequential arrangements of six directions of the rock cleavages can provide a basis for those of the six diagrams related to spacing. Second, the nine correlation charts between the above main parameter and various parameters were arranged in decreasing order of correlation coefficient ($R^2$). These related charts shows a high correlation of power-law function in common. The values of mean spacing, density (${\rho}$) and length of line oa are directly proportional to the value of main parameter, while the values of constant (a), exponent (${\lambda}$), spacing frequency (N), length of line oa', slope of exponential straight line (${\theta}$) and total length ($1mm{\geq}$) are inverse proportional. Third, the results of correlation analysis between the values of parameters for three planes and those for three rock cleavages are as follows. The values of frequency, total spacing, constant, exponent, slope and length of line oa' for three planes and three rock cleavages show an order of R' < G' < H' and H < G < R, respectively. On the other hand, the values of mean spacing, (mean spacing-median spacing), density and length of line oa show an order of H' < G' < R' and R < G < H, respectively. The correlation of the mutually reverse order of the values of parameters between three planes and three rock cleavages can be drawn. This type of correlation analysis is useful for discriminating three quarrying planes.