• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.27 no.10
• /
• pp.30-40
• /
• 2013

In this study the method based on flux linkage in cell was introduced in calculation of eddy currents by cell method. According to this method eddy current distribution and the loss can be evaluated and since the shielding effectiveness by flux cancelation of eddy current can be analyzed, this method is applicable to design of conductive shield. And also the formula of shielding factor were so deduced as to be applicable to finite-width infinite-length shielding sheets and infinite-length underground cable shield. These formula are adaptable to magnetic materials as well as conductive materials. As the results of calculation in model shields are follows. In case of finite-width infinite-length shielding sheet, shielding effectiveness increases with increasing of conductivity. In case of infinite-length underground cable shield, the effectiveness become higher with increasing of permeability. Especially the effectiveness is very high in materials with both high conductivity and permeability in underground cable shield.

• Membrane and Water Treatment
• /
• v.15 no.1
• /
• pp.11-19
• /
• 2024

This study presents the characteristics of growth and morphology of Anabaena sp., a representative filamentous cyanobacterium, depending on temperature variation from 10 to 30 ℃. Both the filament density (or number) and its length of Anabaena were highly affected by temperature, as well as growth stage. Rapid growth at a higher temperature led to an increase in Anabaena filament density, as well as optical density at 680 nm (OD₆₈₀). However, the number of vegetative cells within a single filament of Anabaena grown at 30 ℃ was smaller than those grown at lower temperatures, due to the intercalary division of the filament. Of the three different cells comprising a single Anabaena filament, the vegetative cell marginally affects the growth of Anabaena. The main dimensions of the vegetative cell, i.e., length and width, depend on the temperature and growth stage. The length-to-width (L/W) ratios of vegetative cells and akinetes were relatively consistent regardless of the temperature. However, in vegetative cells with dichotomous growth, the L/W ratio shows clear differences depending on their growth stage. It has been demonstrated that the L/W ratio could be used as an indicator to indirectly predict the growth stage of on-sit Anabaena samples.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.12 no.5
• /
• pp.30-35
• /
• 2013

In order to increase cell efficiency in crystalline silicon solar cell, reduction of light reflection is one of the essential problem. Until now silicon wafer was textured by wet etching process which has random patterns along crystal orientation. In this study, high aspect ratio patterns are manufactured by nano imprint process and reflectance could be minimized under 1%. After that, screen printed solar cell was fabricated on the textured wafer and I-V characteristics was measured by solar simulator. Consequently cell efficiency of solar cell fabricated using the wafer textured by nano imprint process increased 1.15% than reference solar cell textured by wet etching. Internal quantum efficiency was increased in the range of IR wave length but decreased in the UV wavelength. In spite of improved result, optimization between nano imprinted pattern and solar cell process should be followed.

• Journal of Nutrition and Health
• /
• v.31 no.4
• /
• pp.697-707
• /
• 1998

This study was designed to observe the effect of dietary fiber and fat on colon tumor incidence and cell proliferation. Male Sqraue Dawley rats(n=225) at 7 weeks of age, were divided into 3 groups depending on the type of fat b(beef tallow, corn oil and DHA-rich fish oil) and each group was again divided into 3 groups depending on type of fiber(fiber-free, perctin and cellulose) . The experimental diet containing dietary fat at 15%(w/w) and fiber at 6%(w/w) levels was fed for 25 weeks. At the same time, each rats was intramuscularly injected with DMH two times a week for 6 weeks to geive total dose of 180mg/kg body weight. Cell proliferation was measured by in vivo incroporation of bromodeoxyuridine (BrdU) into DNA. Fish oil decreased the tumor incidence (9.67%) compared with beef talow (33.39%) and corn oil (21.21%). Tumor incidence was decreased in all groups that fed cellulose (11.67%) compared with those of fiber-free(21.74%) and pectic(19.70%). Most of tumors was distributed at the site of the distal colon. The rats fed both fish oil and cellulose significantly decreased th enumber of tumors and tumor incidence compared to other groups. Fish oil was more effective in preventing cell prolofieration by decreasing crypt length and labeling index(LI) compared with beef tallow(p<0.05). Cell proliferation in distal colon was more developed to the upper part of the crypt compared to proximal colon. Overall tumor incidence and cell proliferation were more affected by dietary fat. But the effect of dietary fiber was different depending on type of fat in the experimental diet. These results suggest that a DHA -rich fish oil may has more decisive effect in inhibiting the cell proliferation in colon.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.4 no.4
• /
• pp.51-60
• /
• 2001

This study analyzed fractal characteristics of river basin by using GIS. In this study, topographical factors in river basin was grid-analyzed for each cell size by using GIS and regression formula was derived by analyzing correlation among topographical factors and cell size which were calculated here. And, analysis of fractal characteristics of river by using the result calculated from 1) showed that among topographical factors, river length only increases according as cell size increases. The result of calculating fractal dimension for each cell size shows that river length, basin area, and centroidal flow path are 1.028, 1.0026 and 1.0061 respectively.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.24 no.3
• /
• pp.14-19
• /
• 2010

Partial anodic oxidation of Ti-mesh with a wire diameter of ~200[${\mu}m$] produces self-aligned $TiO_2$ nanotube arrays (~50[${\mu}m$] in length) on Ti-mesh substrate. The electrolyte used for anodic oxidation was an ethylene glycol solution with an addition of 1.5 vol. % $H_2O$ and 0.2 wt. % $NH_4F$. A dye-sensitized solar cell utilizing the photoanode structure of $TiO_2$-nanotube/Ti-mesh was fabricated without a transparent conducting oxide (TCO) layer, in which Ti-mesh replaced the role of TCO. The 1.93[%] photoconversion efficiency was low, which can be attributed to both insufficient dye molecules attachment and limited electrolyte flow to dye molecules. The optimized nanotube diameter and length as well as the $TiCl_4$ treatment can improve cell performance.

• Korean Journal of Environmental Agriculture
• /
• v.17 no.4
• /
• pp.335-340
• /
• 1998

This study was conducted to determine the morphological responses of barley seedlings to NaCl stress and to investigate histological changes of cells with transmission electron microscope(TEM) after NaCl stress. Plant height and root length of 10-day old barley seedlings with NaCl stress were reduced and inhibition level was found to be more severe in the plant height than in the root length. The leaf length, leaf width and leaf area were shorter as well with NaCl stress than without NaCl stress. However, there was no difference in the number of roots between NaCl treatments. The weight of dry matter decreased at higher NaCl concentrations, especially at 100mM NaCl. The water content of shoots tend to decrease at higher NaCl concentrations, but there was no difference in the water content of roots, The reduced sugar content was greatly increase than starch. Cellulose content was higher in NaCl stressed-plant than control, and tended to decreased at higher NaCl concentrations. Lignin content also decreased NaCl stressed-plant but there was no tendency at NaCl stress concentrations. Electric conductivity of cell sap with seedlings was high with NaCl stressed-plant. Amount of cell sap gradually increased with time in the roots than in the shoots, The grana of chloroplasts was changed by 150mM NaCl concentration. The christe of mitochondria in root meristematic sells ruined in structure and cell wall of leaf and root was also ruined by NaCl stress.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2011.05a
• /
• pp.702-705
• /
• 2011

Poly-Si wafers with resistivity of 1 [${\Omega}$-cm[ and thickness of 50 [${\mu}m$] were used as a starting material. Various efficiency influencing parameters such as rear surface recombination velocity and minority carrier diffusion length in the base region, front surface recombination velocity, junction depth and doping concentration in the Emitter layer, BSF thickness and doping concentration were investigated. Optimized cell parameters were given as rear surface recombination of 1000 [cm/sec], minority carrier diffusion length in the base region 50 [${\mu}m$], front surface recombination velocity 100 [cm/sec], sheet resistivity of emitter layer 100 [${\Omega}/{\Box}$], BSF thickness 0.5 [${\mu}m$], doping concentration $5{\times}10^{19}\;cm^{-3}$. Among the investigated variables, we learn that a diffusion length of base layer acts as a key factor to achieve conversion efficiency higher than 19.8 %. Further details of simulation parameters and their effects to cell characteristics are discussed in this paper.

• Development and Reproduction
• /
• v.16 no.1
• /
• pp.19-29
• /
• 2012

The ultrastructural characteristics of germ cell differentiations during spermatogenesis and mature sperm morphology in male $Atrina$ ($Servatrina$) $pectinata$ were evaluated via transmission electron microscopic observation. The accessory cells, which contained a large quantity of glycogen particles and lipid droplets in the cytoplasm, are assumed to be involved in nutrient supply for germ cell development. Morphologically, the sperm nucleus and acrosome of this species are ovoid and conical in shape, respectively. The acrosomal vesicle, which is formed by two kinds of electron-dense or lucent materials, appears from the base to the tip: a thick and slender elliptical line, which is composed of electron-dense opaque material, appears along the outer part (region) of the acrosomal vesicle from the base to the tip, whereas the inner part (region) of the acrosomal vesicle is composed of electron-lucent material in the acrosomal vesicle. Two special characteristics, which are found in the acrosomal vesicle of A. ($S$) $pectinata$ in Pinnidae (subclass Pteriomorphia), can be employed for phylogenetic and taxonomic analyses as a taxonomic key or a significant tool. The spermatozoa were approximately $45-50{\mu}m$ in length, including a sperm nucleus (about $1.43{\mu}m$ in length), an acrosome (about $0.51{\mu}m$ in length), and a tail flagellum (about $46-47{\mu}m$). The axoneme of the sperm tail evidences a 9+2 structure.

• The Korean Journal of Malacology
• /
• v.27 no.2
• /
• pp.121-129
• /
• 2011

The ultrastructural characteristics of germ cell development during spermatogenesis and mature sperm morphology of in male Scapharca subcrenata were investigated by transmission electron microscope observation. Spermatogonia are located nearest the outer wall of the acinus, while spermatocytes and spermatids are positioned near the accessory cells. The accessory cells, which is in close contact with developing germ cells, contained a large quantity of glycogen particles and lipid droplets in the cytoplasm. Therefore, it is assumed that they are involved in supplying of the nutrients for germ cell development. The morphologies of the sperm nucleus and the acrosome of this species are the oval shape and cone shape, respectively. Spermatozoa are approximately 45-$50{\mu}m$ in length including a sperm nucleus (about $1.30{\mu}m$ in length), an acrosome (about $0.59{\mu}m$ in length), and tail flagellum (about 43-$47{\mu}m$). The axoneme of the sperm tail shows a 9 + 2 structure. As some characteristics of the acrosomal vesicle structures, the right and left basal rings show electron opaque part (region), and also the anterior apex part of the acrosomal vesicle shows electron opaque part (region). These characteristics of the acrosomal vesicle were found in Acinidae and other several families in subclass Pteriomorphia. These common characteristics of the acrosomal vesicle in subclass Pteriomorphia can be used for phylogenetic and taxonomic analysis as a taxonomic key or a significant tool. The number of mitochondria in the midpiece of the sperm of this species are five, as one of common characteristics appear in most species in Arcidae and other families in subclass Pteriomorphia. The acrosomal vesicles of Arcidae species do not contain the axial rod and several transverse bands in acrosome, unlkely as seen in Ostreidae species in subclass Pteriomorphia, These characteristics can be used for the taxonomic analysis of the family or superfamily levels as a systematic key or tools.