• KIEE International Transactions on Electrophysics and Applications
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• v.11C no.2
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• pp.6-11
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• 2001

Abstract- In this paper, a new Partial Discharge (PD) detection using Pockels cell was proposed and considerable apparent chaotic characteristics were discussed. For this purpose, PD was generated from needle-plane electrode in air and detecte by optical measuring system using Pockels cell, based on Mach-Zehner interferometer, consisting of He-Ne laser, single mode optical fiber, 50/50 beam splitter and photo detector. In addition, the presence of chaos of the PD signals has been investigated by examining their means of qualitative and quantitative information. For the former, return map and 3-dimensional strange attractor have been drawn in order to investigate the presence of chaotic characteristics relevant to PD signals, detected through CT and Peckels sensor respectively, in the normalized time series. The presence of strange attractor indicates the existence of fractal structures in it's phase space. For the latter, several dimension values of strange attractor were verified sequentially. Throughout this paper, it is likely that the chaotic characteristics regarding the PD signals under air are verified.

• Journal of Environmental Science International
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• v.22 no.11
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• pp.1443-1449
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• 2013

This was an experimental study to evaluate temperature reduction and evapotranspiration of extensive green roof. Three test cells with a dimension of $1.2(W){\times}1.2(D){\times}1.0(H)$ meters were built using 4-inch concrete blocks. Ten-centimeter concrete slab was installed on top of each cell. The first cell was control cell with no green roof installed. The second and third cells were covered with medium-leaf type Zoysiagrass (Zoysia japonica) above a layer of soil. Soil thickness on the second cell was 10cm and that on the third cell was 20cm. Air temperature, relative humidity and solar irradiance were measured using AWS (automatic weather system). Temperature on top surface and ceiling of the control cell and temperature on top surface, below soil and ceiling of green roof cells was measured. Evapotranspiration of the green roof cells were measured using weight changes. Compared with temperature difference on the control cell, temperature difference was greater on green roof cells. Between two green roof cells, the temperature difference was greater on the third cell with a thicker soil layer. Temperature differences below soil and on ceilings of green roof cells were found greater than those of the control cell. Between the green roof cells, there was no difference in the temperature reduction effects below soil and on ceilings based on substrate depth. In summary, green roof was found effective in temperature reduction due to evapotranspiration and shading effect.

• Journal of the Korean Mathematical Society
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• v.33 no.3
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• pp.625-639
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• 1996

A convex $RP^n$-structure on a smooth anifold M is a representation of M as a quotient of a convex domain $\Omega \subset RP^n$ by a discrete group $\Gamma$ of collineations of $RP^n$ acting properly on $\Omega$. When M is a closed surface of genus g > 1, then the equivalence classes of such structures form a moduli space $B(M)$ homeomorphic to an open cell of dimension 16(g-1) (Goldman [2]). This cell contains the Teichmuller space $T(M)$ of M and it is of interest to know what of the rich geometric structure extends to $B(M)$. In [3], a symplectic structure on $B(M)$ is defined, which extends the symplectic structure on $T(M)$ defined by the Weil-Petersson Kahler form.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.1189-1192
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• 2008

A new mercury-free flat fluorescent lamp with a single cell having dimension 2.2inches across the diagonal, had been developed which shows a wide, stable operating voltage margin, high luminance and luminous efficacy by adopting the bipolar pulse drive scheme. In this paper, the single cell is expanded into a multi-structured configuration to realize a 32inch sized panel across the diagonal by a simple repetition of the single cells. A driving scheme is proposed for a 2-bit areal selective dimming using dual auxiliary electrodes and bipolar drive scheme.

• ALGAE
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• v.22 no.3
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• pp.147-152
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• 2007

We described two brownish freshwater Cryptomonas species, C. marssonii Skuja and C. pyrenoidifera Geitler as first records in Korea. The identification was based on light microscopy, scanning electron microscopy, and nuclear SSU rDNA sequences analysis. Cryptomonas marssonii is characterized by its sigmoid shape with a sharply pointed and dorsally curved antapex, dorso-ventrally flattened cell, two lateral plastids without pyrenoid, and its dimension of 18-25 μm in length and 8-13 μm in width. Cryptomonas pyrenoidifera is characterized by ovoid to elliptical shape with a partially twisted or rounded antapex, dorso-ventrally biconvex cell, lateral plastids with two pyrenoids, and the dimensions of 15-22 μm in length and 10-14 μm in width. Nuclear SSU rDNA sequences between C. marssonii WCK01 from Korea and CCAC0086 from Gernmay, and between C. pyrenoidifera WCK02 from Korea and CCMP152 from Australia were identical, respectively.

• Journal of the Semiconductor & Display Technology
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• v.16 no.1
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• pp.65-69
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• 2017

This paper presents a Technology-CAD (TCAD) simulation of the characteristics of crystalline Si pillar array solar cells. The junction depth and the surface concentration of the solar cells were optimized to obtain the targeted sheet resistance of the emitter region. The diffusion model was determined by calibrating the emitter doping profile of the microscale silicon pillars. The dimension parameters determining the pillar shape, such as width, height, and spacing were varied within a simulation window from ${\sim}2{\mu}m$ to $5{\mu}m$. The simulation showed that increasing pillar width (or diameter) and spacing resulted in the decrease of current density due to surface area loss, light trapping loss, and high reflectance. Although increasing pillar height might improve the chances of light trapping, the recombination loss due to the increase in the carrier's transfer length canceled out the positive effect to the photo-generation component of the current. The silicon pillars were experimentally formed by photoresist patterning and electroless etching. The laboratory results of a fabricated Si pillar solar cell showed the efficiency and the fill factor to be close to the simulation results.

• Current Photovoltaic Research
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• v.2 no.3
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• pp.84-87
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• 2014

Protection of solar cell surface is important to prevent from dust, pollen, sand, etc. Therefore, development of large area antifouling film is urgent for high performance of solar cells. The surface of silica spheres was modified to fabricate large area antifouling film. The surface of monodisperse silica spheres has been modified with 3-(trimethoxysilyl) propylmethacrylate (TMSPM) to fabricate large area photonic crystal. Although the surface modification of silica spheres with TMSPM has been failed for the base catalyst, the second trial using acid catalyst showed the following results. The FTIR absorption peak at $1721cm^{-1}$ representing C=O stretching vibration indicates that the TMSPM was attached on the surface of silica spheres. The methanol solution comprised of the surface modified silica spheres (average diameter of 380 nm) and a photoinitiator was poured in the patterned silicon wafer with the dimension of 10 cm x 10 cm and irradiated UV-light during the self-assembly process. The result showed large area crack and defect free nanostructures.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.239-240
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• 2006

In this study, we examined all peaks of confocal Raman spectra as peaks are the most important features for discrimination between basal cell carcinoma (BCC) and normal tissue (NOR). 14 peaks were extracted from these peaks using decision tree. For dimension reduction, frequently selected 4 peaks were chosen. They are located at 1014, 1095, 1439, $1523cm^{-1}$. These peaks were used as an input feature of the multilayer perceptron networks (MLP). According to the experimental results, MLP gave classification error rate of about 6.5%.

• Journal of the Mineralogical Society of Korea
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• v.4 no.2
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• pp.90-98
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• 1991

This study introduces a new structural model of 1M 2:1 trioctahedral clay minerals or, more generally, 2:1 trioctahedral phyllosilicates. The structural model requires only the chemical formulae of the clay minerals as an input and uses the regression relation (Radoslovich, 1962) to calculate the a- and b-dimensions of the phyllosilicates with the given chemical formulae. The atomic coordinates of the constituent atoms are geometrically calculated for C2/m space group under the assumption that the interatomic distances are constant. To determine the c-dimension, this study calculates the binding energies of 1M 2:1 trioctahedral phyllosilicates as a function of d(001) and find the minimum energy producing d(001). The structural model generates the cell dimensions, interaxial angles, interatomic distances, octahedral, tetrahedral and interlayer thickness, polyhedron deformation angles and atomic coordinates in the unit cell. The simulated structural parameters of phlogopite and annite are very close to the reported data by Hazen and Burnham (1973), suggesting that the structure simulation using only the chemical formule is successful, and thus, that the structural model of this study overcomes the difficulties in the previous models by other investigators.

• Journal of the Mineralogical Society of Korea
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• v.10 no.1
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• pp.50-59
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• 1997

the crystal structure of pale green gem-quality olivine from Bisbee mine,Arizona, (Mg1.83Fe0.18)Si0.99O4, a=4.7608(4)$\AA$, c=5.9903(6)$\AA$, c=5.9903(4)$\AA$, V=291.49(1)$\AA$, Pbnm, Z=4 has been refined by both single-crystal and Rietveld methods to R(%) indices of 2.20 and 9.07, respectively. Comparison of site occupancies, cell dimensions, atomic coordinations, and interatomic distances/angles obtained from both methods shows that the Rietveld method produces more accurate site scattering values, cell dimension, and atomic positions than the single-crystal method. This indicates that the Rietveld method is a useful technique for the structural characterization and crystal-chemical study of powdered samples of natural minerals and synthetic materials.