• Applied Microscopy
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• v.52
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• pp.8.1-8.7
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• 2022

The Korean trident goby, Tridentiger brevispinis, lives in adverse habitats that can easily become hypoxic due to low precipitation, regional dry periods, and high amounts of solar radiation. Histological and morphometric studies revealed the goby's specialized skin (35.4-150.0㎛ in thickness), consisting of an epidermis and dermis. The thicker epidermis comprises an outermost surface layer (having taste buds, stratified fattened cells, mucous cells, pigment cells, and stratified polygonal cells), middle layer (having stratified polygonal cells), and stratum germinativum (stratified columnar cells). In particular, the dermis has scales, well-developed vascularization, and a few blood capillaries just above the basement membrane, and a reduced diffusion distance was present in the lateral body. Consequently, adaptations such as thicker epidermis, well-developed vascularization, few blood capillaries, and a reduced diffusion distance may provide cutaneous respiration for survival in poorly oxygenated water during the periodic dry season.

• Proceedings of the Korean Geotechical Society Conference
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• 1997.10a
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• pp.391-398
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• 1997

• Proceedings of the KSME Conference
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• 2005.11a
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• pp.86.1-86.1
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• 2005

• Proceedings of the KSME Conference
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• 2005.11a
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• pp.66.2-66.2
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• 2005

• Proceedings of the Korean Nuclear Society Conference
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• 2001.10a
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• pp.122.1-122
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• 2001

• Communications for Statistical Applications and Methods
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• v.18 no.4
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• pp.423-431
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• 2011

For procuring more sensitive information and estimating stratum target population proportion as well as an overall one form a sensitive population composed of several strata we suggest a two-stage stratified unrelated question model that uses stratified random sampling instead of simple random sampling in the two-stage unrelated question model by Kim et al. (1992) and extend it to the three-stage stratified unrelated question model. We also deal with the proportional and optimal allocation problems in each suggested model, compare the relative efficiency of the suggested two models, and show that the three-stage stratified unrelated question model is more efficient than the two-stage one in view of the variance.

• Ocean and Polar Research
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• v.30 no.3
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• pp.261-275
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• 2008

The profile of a fixed site at station M ($34.77^{\circ}N,\;129.13^{\circ}E$) in the Korea Strait was studied from March 2006 to February 2007. The aim was to understand the relationship between the annual thermal stratification pattern and seasonal variation in phytoplankton community structure. Physicochemical factors including temperature, salinity and nutrient concentrations, which strongly influence the proliferation and diversity of phytoplankton, were measured. The study period was divided into three due to the characteristic of thermohaline structures; mixed I (March-May 2006), stratified (June-November 2006) and mixed II(December 2006-Feburuary 2007). Diatoms dominated during the mixed I (89%) and II (48%) periods, while nanoplankton group occupied over 83% of total population during the stratified period. The dominant species during the mixed I and II was Chaetoceros socialis (47% and 29%, respectively), while during the stratified period Gyrodinium sp.(4%) was the most dominant. Averaged total chl a concentrations during the mixed I and II periods were 0.61 mg $m^{-3}$ and 0.72 mg $m^{-3}$, respectively, which were at least two-fold higher than that during the stratified period (0.30 mg $m^{-3}$). The vertical mixing and convection process of the water column induced nutrient supply from the bottom layer to the euphotic zone. It also led to the dominance of diatoms during the mixed periods, whereas small phytoplankton prevailed over large phytoplankton as stratification blocked the upward movement of nutrients to subsurface during the stratified period. During the mixed I and II periods, microplanktonic chl a dominated concentrations (50% and 48%, respectively), while picoplanktonic chl a occupied over 37% of total chl a during the stratified period.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.16 no.11
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• pp.1077-1083
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• 2004

This study is to systematically analyze the effect of various kinds of design factors on the performance of stratified thermal storage tank. Taguchi method, known as a very reasonable tool in the parametric study, is employed in the present work. Three dimensional unsteady numerical experiment is conducted for 4 design parameters of stratified thermal storage tank: inlet Reynolds number, Froude number, diffuser size d with 3 levels (Re=400, 800, 1200, Fr=0.5, 1.0, 2.0 and d=150 mm, 200mm, 300 mm) and diffuser shape with 2 levels. Orthogonal array $L_{18}(2{\times}3^7)$ is adopted for the analysis of variance. The result gives quantitative estimation of the various design parameters affecting the performance and helps to select the main factors for the optimum design of stratified thermal storage tank. Reynolds number is found to be the most dominant parameter and the diffuser shape plays significant role on the performance of stratified thermal storage tank. Based on this finding, the prior questions on the contribution of the diffuser shape proposed by the authors become clear. The optimum condition for the performance is a set of d=300mm, Re=800, and radial regulated plate diffuser. Conformation test shows the repeatability in the analysis and $1.3\%$ difference between the estimated thermocline thickness and that of numerical result.

• Journal of the Korean Society of Combustion
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• v.17 no.4
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• pp.11-20
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• 2012

The Blow-off characteristics of LPG/air lean pre-mixed flames were experimentally investigated using a double and a multiple concentric coflow burners. Experiments were conducted to understand the effects of recirculation motion, thermal interaction between flames, and stratified flame configuration. Here, the stratified premixed flame is a "new concept" of a flame that sequentially contains fuel rich, stoichiometric, and fuel lean reaction zones in a flame. The blow-off from a lean premixed flame was significantly suppressed with recirculation motion. The recirculation motion by itself, however, was not sufficient to prevent the blow-off when the equivalence ratio became low. The existence of a inner premixed flame could also help to prevent the blow-off of lean premixed flame; however, the blow-off suppression effect was rather diminished by weakened recirculation motion with the presence of inner flame. The inner flame could be separated from an outer flame on a multiple concentric coflow burner, causing recirculation motion as well as thermal interaction between flames to become effective; therefore, the blow-off was further suppressed. The lean premixed flame could be stabilized with a fuel rich premixed flames that was produced with the supply of fuel through an inner nozzle. The penetration of lean premixed gas from outside into the fuel stream produced a lifted rich premixed flame. Chemiluminescence images of OH, CH, and $C_2$ radicals confirmed the structure of a stratified premixed flame. The stable premixed flames could be obtained at the very fuel lean condition by applying the stratified premixed flame concept.

• Nuclear Engineering and Technology
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• v.17 no.1
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• pp.34-44
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• 1985

The main purpose of this work is to study the effects of (1) configuration, size, and materials of electrodes, (2) flow pattern, (3) electrode position with respect to a dielectric boundary on the void fraction measurement and flow regime characterization by capacitance transducers. From the experimental results, relationships between the measured relative capacitance and void fraction are obtained for both annular and stratified flow systems under static condition, and this result is compared with theoretical predictions. From this study it can be concluded that (1) the strip-type electrodes are more sensitive than ring-type electrodes for both annular and stratified flows, (2) electrode size does not affect the relative capacitance vs. (1-$\alpha$) curve, and (3) electrode position is important for stratified flows but it has no effect on annular flows.