• KOREAN JOURNAL OF CROP SCIENCE
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• v.29 no.4
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• pp.307-314
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• 1984

One hundred winter wheat cultivars obtained from the world collections in Korea were planted in 1982. Stomatal frequency of flag leaf of these cultivars were measured, and among these 21 cultivars which showed different stomatal frequency were selected to investigate the relationship of their stomatal frequencies and other characters such as culm length, heading date and characters related to leaf. Stomatal frequency of flag leaf of 100 cultivars different significantly, ranging from 51 to 90 stomata mm$^{-2}$ for the adaxial and 35 to 65 for the abaxial surfaces of leaf. Stomatal frequency was always greater on the adaxial than on the abaxial surface. Mean ratios (adaxial/abaxial) were 1.5 for the flag leaf and 1.3 for the from second to fouth leaves. Among 21 cultivars examined, stomatal size which measured guard cell length varied from 38.5 to 46.6$\mu$ for adaxial surface and from 39.4 to 49.4$\mu$ for abaxial. A negative correlation was obtained between stomatal frequency and its size. Stomatal frequency decreased from flag (L$_1$) to lower leaves, progresively. Stomatal frequency on L$_1$ sheath was compared to those on L$_3$ and L$_4$ abaxial surface of leaf. More stomatal frequency on top and center of adaxial surface showed than that on basal part of a leaf but the abaxial surface resulted in reverse of adaxial one. Cultivars with high stomatal frequency on flag leaf showed higher stomatal frequency on the other leaves and sheaths. Positive correlation between stomatal frequency and other characters such as, culm length, heading date and chlorophyll content showed statistical significance, whearas it revealed the negative correlation of stomatal frequency with leaf weight, leaf area and stomatal aperture. However, no relation appeared between stomatal frequency and leaf vein.

• Economic and Environmental Geology
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• v.44 no.4
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• pp.289-302
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• 2011

Since the frequency of the earthquake occurrence in Korean peninsular is continuously increasing, the possibility that massive landslides are triggered by earthquake is also growing in Korea. Previously, the landslide is known to be induced by large magnitude earthquake, whose magnitude is larger than 6.0. However, the landslide can be induced by only small magnitude earthquake, especially in the fully saturated soil. Therefore, the susceptibility of landslide caused by small magnitude earthquake in fully saturated soil is analyzed in this study. For that, the topographical and geological characteristics of the site were obtained and managed by GIS software. In the procedure of the study, slope angle, cohesion, friction angle, unit weight of soil were obtained and constructed as a spatial database layer. Combining these data sets in a dynamic model based on Newmark's displacement analysis, the landslide displacements were estimated in each grid cell. In order to check out the possibility of the earthquake induced landslides, the level of the groundwater table is varied from dry to 80% saturated soil. In addition, in order to analyze the effect of the magnitude of earthquake and distance to epicenter, four different earthquakes epicenters were considered in the study area.

• Applied Microscopy
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• v.32 no.1
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• pp.57-66
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• 2002

The structures of sucker of two Cobiidae; Common freshwater goby and Triden goby were observed by light and electron microscopy. Scanning electron microscopy revealed the characteristic narrow ridges and grooves on the apical portion of sucker of Common freshwater goby, and hexagonal structures similar to a honeycomb representing the intercellular junctional area on the middle and basal portions. Some ridges were present on the epithelial surface on the middle and basal portions. The openings of several mucus-secreting cells were present between main epithelial cells. Light and transmission electron microscopy revealed the core of the fin; soft rays with a surrounding dense collagen fiber layer. Some loosely arranged fibers (collagen fiber) radiated toward the surface epithelium. The surface epithelium was cuboidal or columnar in shape. Scanning electron microscopy revealed the coiled irregular ridges and grooves, which was less developed and had sparser distribution than in Common freshwater goby, on the apical portion of sucker of Triden goby. The middle and basal portions had honeycomb structures as in Common freshwater goby. Fewer mucoussecreting cells were present. Light and transmission electron microscopy showed the core of soft rays, dense collagen fiber layer, however, the radiating fibers observed in the Common freshwater goby was rarely present. The sucker was thinner because the epithelium is squamous or polygonal in shape and rare presence of the radiating fibers.

• Applied Microscopy
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• v.41 no.3
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• pp.163-168
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• 2011

Tiger barb (Puntius tetrazona Bleeker, 1855) is a teleost belonging to Cyprinidae. The oogenesis of tiger barb was investigated by light microscope. The ovary was of white and ellipsoidal shape with the major axis 2 cm and the minor axis 1 cm. Cytoplasm of oogonia was basophilic and many nucleoli were located at inside of nuclear membrane. In early stage of primary oocyte, yolk vesicles were distributed only in the marginal area. In secondary oocyte, the egg envelope was formed and yolk vesicles was formed in the cytoplasm. The basophilic substance of cytoplasm was changed to acidic. In case of matured egg, thickness of egg envelope and size of egg were increased. The yolk vesicles were changed to yolk mass in accordance with development. Also, there is not the formation of oil droplets in cytoplasm. In conclusion, the oogenesis of tiger barb was characterized by the increase in cell size, the formation of yolk, the decrease of basophilic substance in the cytoplasm, and formation of yolk mass.

• Journal of fish pathology
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• v.4 no.1
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• pp.31-39
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• 1991

Vibrio sp. S-1-2 was isolated from seawater in the Masan bay and its bacterial characteristics and bioaccumulation of $CdCl_2$ in the cell were investigated. As the result of microscopic and biochemical test, the S-1-2 strain was identified to Vibrio sp. and this strain can be tolerated even in 200 ppm $CdCl_2$ media, however its growth was inhibited. In 25 ppm $ZnCl_2$ media, the growth of Cd resistant Vibrio sp. S-1-2 was promoted at later stage of growth. The growth of Vibrio sp. S-1-2 was inhibited on 25 ppm $CuCl_2$ and $PbCl_2$ media and was not able to grow in 25 ppm $HgCl_2$ media at all. The uptake of cadium in the cells was increased exponentially with increasing concentration of $CdCl_2$ in media. But the uptake rate of cadmium was suddenly inhibited at 50 ppm $CdCl_2$ media. Optimal pH and NaCl concentration for bioaccumulation of $CdCl_2$ were 8-9 and 1-2%, respectively. In the case of pH, maximum dpm value was found at pH 7 after 96 hours culture and in the case of NaCl concentration, it was detected in 2% NaCl media after 36 hours culture.

• Journal of the Institute of Convergence Signal Processing
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• v.8 no.3
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• pp.156-162
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• 2007

The parallel beam SPECT system acquires projection data by using collimators in conjunction with photon detectors. The projection data of the parallel beam SPECT system is, however, blurred by the point response function of the collimator that is used to define the range of directions where photons can be detected. By increasing the number of parallel holes per unit area in collimator, one can reduce such blurring effect. This approach also, however, has the blurring problem if the distance between the object and the collimator becomes large. In this paper we consider correction methods for artifacts caused by non-circular orbit of parallel beam SPECT with many parallel holes per detector cell. To do so, we model the relationship between the object and its projection data as a linear system, and propose an iterative reconstruction method including artifacts correction. We compute the projector and the backprojector, which are required in iterative method, as a sum of convolutions with distance-dependent point response functions instead of matrix form, where those functions are analytically computed from a single function. By doing so, we dramatically reduce the computation time and memory required for the generation of the projector and the backprojector. We conducted several simulation studies to compare the performance of the proposed method with that of conventional Fourier method. The result shows that the proposed method outperforms Fourier methods objectively and subjectively.

• Development and Reproduction
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• v.5 no.1
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• pp.17-21
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• 2001

This study was conducted to investigate the expression pattern of Trypsin-like enzyme and the effect of a trypsin inhibitor(benzimidine) on hatching process during in-vitro culture of mouse preimplantation embryos. The Trypsin-like enzyme was identified by rhodamine-conjugated Trypsin substrate probe. The expression of trypsin-like enzyme was firstly detected at the late morula stage, and the enzyme was uniformly localized in the trophectoderm of late blastocysts. Especially, intense fluorescence was observed in the blebbing area of hatching blastocysts. Bisbenzamidine, contained in culture media, did not alter embryonic development from 4-cell stage to the expanded blastocyst but decrease the hatching rate in ImM concentration (15.8% vs 89.7%, p<0.02). In the treatment of bisbenzimidine (5mM) for 12 hours according to the embryonic stage of mouse, the hatching rate of control (83.0%) and treatment in late blastocysts (8.7%) were significantly (p<0.01) different. From these results, we suggested that the hatching enzyme having trypsin-like activity was localized from the late morula stage, and the hatching process by this enzyme was activated in the late blastocyst stage of mouse embryos.

• Applied Microscopy
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• v.38 no.4
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• pp.315-319
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• 2008

Glow-light tetra, Hemigrammus erythrozonus is a teleost belonging to Characidae. The natural habitate of this fish is the wild in the Essequibo river, Guyana and South America. The oogenesis of glow-light tetra was investigated by light microscopy to compare with those of other families. A pair of ovary was located between swim bladder and intestines. The ovary was of white color and ellipsoidal shape with the major axis 11 mm and the minor axis 4 mm. Cytoplasm of oogonia was basophilic and many nucleoli were located at inside of nuclear membrane. In primary oocytes, yolk vesicles were distributed only in the marginal area and egg envelope was not formed on the outside of an egg. In secondary oocytes, the egg envelope was formed and yolk vesicles in the cytoplasm were increased than the earlier stage. The amount of basophilic substance was decreased. In case of matured egg, thickness of egg envelope and size of egg were increased, basophilic substance was distributed in only around the egg envelope. The yolk vesicles were changed to yolk mass in accordance with development. In conclusion, the oogenesis of glow-light tetra, Hemigrammus erythrozonus was characterized by the increase in cell size, the formation and accumulation of yolk, and the decrease of basophilia a in the cytoplasm. The oogenesis of glow-light tetra seems to share common patterns in Characidae, teleost and have a similar pattern with other teleost.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.24 no.5
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• pp.303-314
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• 1991

Hypoxic bottom $(\leq2.0ml/l),\;40\%\;oxygen\;saturation)$ is formed in the semi-closed Wonmun bay during summer and autumn early. This study was carried out to know seasonal distribution of marine bacteria and the role of marine bacteria for forming the hypoxic bottom at Wonmun bay during summer and autumn early, 1990. During the study periods, 170 bacterial strains were isolated from sea water and sediment. Viable cell counts were ranged between $10^5-10^7\;cells/ml$. The dominant species were Acinetobacter spp. in spring, Flavobacerium spp. in summer, Pseudomonas spp. in autumn, Serratia spp. in winter. Because ETSA(Electron Transport System Activity) reveals potential consumption of oxygen in the aquatic microorganisms, the ETSA was used as potential consumption of oxygen in this study. The potential consumption of oxygen was in the range of $232.4-637.5{\mu}l/O_2/l/day$ by marine organism and $142.6-432.4{\mu}l/O_2/l/day$ by marine bacteria during the study periods. The ratio of potential oxygen consumption of marine bacteria to total marine microorganism was 0.54. The potential consumption of oxygen by marine bacteria closely related with the number of viable cells. Consequently, bacteria play an important role to form Hypoxic bottom at marine environment.

• Korean Chemical Engineering Research
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• v.43 no.1
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• pp.60-65
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• 2005

The electrosorption of U(VI) from waste water was carried out by using activated carbon fiber(ACF) felt electrode in a continuous electrosorption cell. In order to enhance the electrosorption capacity at lower potential, ACF felt was chemically modified in acidic, basic and neutral solution. Pore structure and functional groups of chemically modified ACF were examined, and the effect of treatment conditions was studied for the adsorption of U(VI). Specific surface area of all ACFs decreases by this treatment. The amount of acidic functional groups decreases with basic and neutral salt treatment, while the amount increases a lot with acidic treatment. The electrosorption capacity of U(VI) decreases on using the acid treated electrode due to the shielding effect of acidic functional groups. Base treated electrode enhances the capacity due to the reduction of acidic functional groups. The electrosorption amount of U(VI) on the base treated electrode at -0.3 V corresponds to that of ACF electrode at -0.9 V. Such a good adsorption capacity was not only due to the reduction of shielding effect but also the increase of $OH^-$ in the electric double layer on ACF surface by the application of negative potential.