• Proceedings of the Materials Research Society of Korea Conference
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• 2011.05a
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• pp.8.1-8.1
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• 2011

Nanocrystalline titanium dioxide ($TiO_2$) materials have been widely used as an electron collector in DSSC. This is required to have an extremely high porosity and surface area such that the dye can be sufficiently adsorbed and be electronically interconnected, resulting in the generation of a high photocurrent within cells. In particular, their geometrical structures and crystalline phase have been extensively investigated as important issues in improving its photovoltaic efficiency. In this study, we present a new strategy to fabricate a photoelectrode having a periodic structured $TiO_2$ film templated from 1D or 3D polystyrene (PS) microspheres array. Monodisperse PS spheres of various radiuses were used for colloidal array on FTO glasses and two types of photoelectrode structures with different $TiO_2$ materials were investigated respectively. One is the igloo-shaped electrode prepared by $TiO_2$ deposition by RF-sputtering onto 2D microsphere-templated substrates. At the interface between the film and substrate, there are voids formed by the decomposition of PS microspheres during the calcination step. These holes might be expected to play the predominant roles as scattering spherical voids to promote a light harvesting effect, a spacious structure for electrolytes with higher viscosity and effective paths for electron transfer. Additionally the nanocrystalline $TiO_2$ phase prepared by the RF-sputtering method was previously reported to improve the electron drift mobility within $TiO_2$ electrodes. This yields solar cells with a cell efficiency of 2.45% or more at AM 1.5 illumination, which is a very remarkable result, considering its $TiO_2$ electrode thickness (<2 ${\mu}m$). This study can be expanded to obtain higher cell efficiency by higher dye loading through the increase of surface area or multi-layered stacking. The other is the inverse opal photonic crystal electrode prepared by titania particles infusion within 3D colloidal arrays. To obtain the enlargement of ordered area and high quality of crystallinity, the synthesis of titania particles coated with a organic thin layer were applied instead of sol-gel process using the $TiO_2$ precursors. They were dispersed so well in most solvents without aggregates and infused successfully within colloidal array structures. This ordered mesoporous structure provides the large surface area leading to the enough adsorption of dye molecules and have an light harvesting effect due to the photonic band gap properties (back-and-forth reflection effects within structures). A major advantage of this colloidal array template method is that the pore size and its distribution within $TiO_2$ photoelectrodes are determined by those of latex beads, which can be controlled easily. These materials may have promising potentials for future applications of membrane, sensor and so on as well as solar cells.

• Journal of Digital Convergence
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• v.16 no.3
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• pp.429-438
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• 2018

Brad Bird, a screenwriter and animation director in the United States, criticized the situation in which most animations were produced and released for the children since the early 2000s. He said that animation is an art form capable of conveying messages not only to children but also to adults, and that their development potential is high. In this study, I analyzed overall components such as narrative structure, character, subplot, symbol, and foreshadow of Brad Bird's animated feature films , , and examined his narrative features and strategies. As a result, the narrative features of animation as an art form are as follows: First, conveying the message of a serious subject that will deeply sympathize with adults as well as children. Second, expressing the social agenda which criticizes the contradiction of the real world and the periodic mistakes. Third, solid narrative structure through a dense plot based on realistic situation setting. I hope that this study will be used as basic research material for various animation production in the future.

• Journal of the Korean Magnetics Society
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• v.26 no.6
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• pp.179-184
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• 2016

For an industrial spin-transfer torque (STT) MRAM, low switching current and high thermal stability are required, simultaneously. For this point of view, it is essential to find magnetic materials which satisfy high spin polarization and strong perpendicular magnetocrystalline anisotropy (MCA). In this paper, we investigate electronic structures and MCA energies of perovskite $CoFeX_3$ (X = O, F, S, Cl). For X = F and Cl, spin polarization at the Fermi level are 97 % and 96 %, respectively, which are close to a half metal. Furthermore, Co-terminated 5-monolayer (ML) $CoFeX_3$ (X = O, F, S, Cl) films show perpendicular MCA. In particular, the MCA energy of the Co-terminated $CoFeCl_3$ is about 1.0 meV/cell which is three times larger than that of a 5-ML CoFe film. Therefore, we expect to realize a magnetic material with high spin polarization and strong perpendicular MCA energy by utilizing group 6 and 7 elements in the periodic table, and to contribute to commercializing of the STT-MRAM.

• Journal of the Society of Disaster Information
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• v.15 no.4
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• pp.479-492
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• 2019

Purpose: The purpose of this study is to accurately analyze the damage of bridges in order to determine whether fire bridges can be used continuously or to provide information on maintenance augmentation data. Method: XRD, SEM and EDS analyzes of concrete were carried out to estimate the fire temperature transferred to the structure, and analyzed by depth and area from PSCI beam and bottom plate concrete surface. Results: Test results G_12,11 for the fire zone concrete were confirmed to be affected by heat up to depth of 60mm and the temperature of the hydrothermal heat was above 1000℃. Also, the girder G_10,9,8 was relatively weakly damaged compared to G_12,11, and the degree of damage was confirmed to be affected by heat up to a depth of 40 mm. Conclusion: Based on the analyzed data, it is considered that if the repair / reinforcement and periodic inspection are carried out, the bridge can secure sufficient safety even considering the damage caused by the fire.

• Journal of Life Science
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• v.10 no.2
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• pp.1-8
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• 2000

This experiment was performed to study the structure of esophageal mucousa and the histochemical properties of glycosaminoglycans of esophageal mucous cells in four teleostean species, i.e., Agramus agramus, Inimicus japonicus, Epinephelus chlorostigma and Helicolenus dactylopterus. To observe the structure of eosphageal mucosa, hematoxylin-eosin(H-E) staining was used. The glycosaminoglycans was stained with PAS(periodic acid schiff), alcain blue(AB) pH 2.5, AB pH 1.0, aldehyde fuchsin(AF) pH 1.7, AF pH 1.0, AB pH 2.5-PAS, AB pH 1.0-PAS and AF pH 1.7-alcian blue pH 2.5. As for the amount and histochemical composition of glycosaminglycans in Agramus agramus, most of mucous secreting columnar cell and mucous cells contain large and moderate amount of neutral glycosaminoglycans. A few of mucous cells having small amount of neutral glycosamino-glycans and minimal amount of sulfated glycosamino-glycans. In Inimicus japonicus, the esophageal mucous cells were composed of most of medium sized and large mucous cells with moderate amount of neutral glycosaminoglycanonly only, a few of medium sized and large mucous cells and most of small mucous cells with considerable amount of neutral glycosaminoglycans and minimal to small amount of nonsulfated glycosaminoglycans, and a feq of small mucous cells with small amount of neutral glycosaminoglycans and minimal amount of sulfated glycosaminoglycans. In Epinephelus chlorostigma, most of medium sized and large mucous cells were mixed small amount of neutral glycosaminoglycans with sulfated glycosaminoglycans, a few of which were contained with moderate or considerable amount of neutral glycosaminoglycans with sulfated glycosaminoglycans, while most of small mucous cells containing considerable amount of neutral glycosaminoglycans and small to moderate or considerable to minimal amount of nonsulfated glycosaminoglycans(sialomucin) a few of which containing a mixture of considerable amount of neutral glycosaminoglycans and considerable amount of nonsulfated glycosaminoglycans(sialomucin)only. In Helicolenus dactylopterus, most of medium sized and large mucous cells, mixing with moderate to considerable amount of neutral glycosaminoglycans and small to moderate amount of sulfated glycosaminoglycans, while most of small mucous cells with considerable amount of nonsulfated glycosaminoglycans (sialomucin), a few of which having a mixture of considerable amount of neutral glycosaminoglycans and considerable or small amount of nonsulfated glycosaminoglycans(sialomucin).

• Korean Journal of Heritage: History & Science
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• v.33
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• pp.210-255
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• 2000

This study aims to classify the framework and arrangement of interior columns (Naeju) which are used in single-story Buddhist halls into several types, and to develop a theory on the process of changes among those types. Since interior columns are building materials which hold up the roof structure and make partitions in the interior space of halls, their framework and arrangement is closely linked to the development of building technology and is expected to reflect new architectural needs. The kinds of interior columns classified by the shape of framework are goju, chaduju, oepyonju, naepyonju. The arrangement of interior columns can he classified by two methods: One which counts the number of the interior column arrangements in a hall, and the other whose classification relates with the side wall columns - Jeongchibup and yijubup. With the combination of these classifications, we can divide the framework and arrangement of interior columns into 8 types From the remains of Korean and Chinese Architecture, we can presume that before the late-Goryo period, jeongchibup had always been applied in the construction of Buddhist halls, and gamju(column reducing) had only been used in examples of small scale. After the founding of Choseon Kingdom, however, national policy had weakened the economic power of Buddhist temples. Because of that, large-scale outdoor Buddhist mass was replaced by small-scale indoor mass, and for this reason, though the scale of Buddhist halls became smaller, the need for a broad interior space became stronger. Thus in early-Choseon period, reduction of interior columns became widely spread. Those types of framework and arrangement of interior columns where yijubup was applied were developed because the rear interior columns arrangements, in order to expand the interior space, have moved backward. Among these types, yiju-goju and yiju-chaduju were developed for the Buddhist halls with paljak roof(hipped-gabled roof), where the load of their side eaves caused structural problems at the side walls. And oepyonju type was for the small-scale and middle-scale Buddhist halls which needed more interior space but didn't want the extension of roof structure. From the local and periodic distribution of each types, we can conclude that the types jeongchi-goju, jeongchi-chaduju and yiju-chaduju have been settled as typical technique of local carpenters. Oepyonju was developed later than the other types, but for its merit of low cost, it became a popular type across the nation.

• Journal of the Microelectronics and Packaging Society
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• v.26 no.1
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• pp.9-15
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• 2019

Here, we present a facile route to fabricate a vertically stacked 3D porous structure-based triboelectric nanogenerator (TENG) that can be used to harvest energy from the friction in a repetitive contact-separation mode. The unit component of TENG consists of thin Al foil electrodes integrated with microstructured 3D foams such as Ni, Cu, and polyurethane (PU), which provide advantageous tribo-surfaces specifically to increase the friction area to the elastomeric counter contact surfaces (i.e., polydimethylsiloxane, PDMS). The periodic contact/separation-induced triboelectric power generation from a single unit of the 3D porous structure-based TENG was up to $0.74mW/m^2$ under a mild condition. To demonstrate the potential applications of our approach, we applied our TENGs to small-scale devices, operating 48 LEDs and capacitors. We envision that this energy harvesting technology can be expanded to the applications of sustainably operating portable electronic devices in a simple and cost-effective manner by effectively harvesting wasted energy resources from the environment.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.10 no.1
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• pp.100-112
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• 2005

Soil temperature was measured from the surface to 40 cm depth at three stations with different heights in tidal flat of Gomso Bay, west coast of Korea, for one month in every season 2004 to examine the thermal structure and the variation. Mean temperature in surface layer was higher in summer and lower in winter than in lower layer, reflecting the seasonal variation of vertically propagating structure of temperature by heating and cooling from the tidal flat surface. Standard deviation of temperature decreased from the surface to lower layer. Periodic variations of solar radiation energy and tide mainly caused short term variation of soil temperature, which was also intermittently influenced by precipitation and wind. Time series analysis showed the power spectral energy peaks at the periods of 24, 12 and 8 hours, and the strongest peak appeared at 24 hour period. These peaks can be interpreted as temperature waves forced by variations of solar radiation, diurnal tide and interaction of both variations, respectively. EOF analysis showed that the first and the second modes resolved 96% of variation of vertical temperature structure. The first mode was interpreted as the heating antl cooling from tidal flat surface and the second mode as the effect of phase lag produced by temperature wave propagation in the soil. The phase of heat transfer by 24 hour period wave, analyzed by cross spectrum, showed that mean phase difference of the temperature wave increased almost linearly with the soil depth. The time lags by the phase difference from surface to 10, 20 and 40cm were 3.2,6.5 and 9.8 hours, respectively. Vertical thermal diffusivity of temperature wave of 24 hour period was estimated using one dimensional thermal diffusion model. Average diffusivity over the soil depths and seasons resulted in $0.70{\times}10^{-6}m^2/s$ at the middle station and $0.57{\times}10^{-6}m^2/s$ at the lowest station. The depth-averaged diffusivity was large in spring and small in summer and the seasonal mean diffusivity vertically increased from 2 cm to 10 cm and decreased from 10 cm to 40 cm. Thermal propagation speeds were estimated by $8.75{\times}10^{-4}cm/s,\;3.8{\times}10{-4}cm/s,\;and\;1.7{\times}10^{-4}cm/s$ from 2 cm to 10 cm, 20 cm and 40 cm, respectively, indicating the speed reduction with depth increasing from the surface.

• Journal of Korean Society of Forest Science
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• v.90 no.3
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• pp.295-305
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• 2001

This study was conducted to reveal stand structure and competition status by site types of natural deciduous forest in Pyungchang, Kangwon-do. The study site was divided by nine different types based on elevation(higher than 1,000m, 700~1,000m. lower than 700m) and topography(ridge, slope, valley). The objective of this study is to provide a basic information necessary for the environment-friendly management methods of natural deciduous forest on the basis of the stand structure and competition status by site types. It is confirmed that the range from 700m to 1,000m in elevation was the most suitable for stand growth. Species diversity and richness index also tended to be increased as elevation decreased. The ridge was the best in terms of stand growth by topography and followed by slope and valley in order. In addition, as expected, species with high importance value showed relatively low evenness index. The distance-independent competition index was selected as the best competition index model in seven site types of natural deciduous forest. On the other hand, the distance-dependent competition index was highly correlated with periodic annual increment of diameter in both ridge at higher than 1,000m and valley of 700m to 1,000m in elevation. It is proved, as a result, that the best competition index model is somewhat different by site types. From the analysis growth characteristics and competition status by site types, it is identified that the species with high importance value performed well in both growth and competition. The growth of Q. mongolica was excellent in the areas of higher elevation than 700m. Although K. pilus had relatively low importance value in higher elevation than 1,000m and ridge of 700m to 1,000m, the species had stronger competition status rather than other species. Also, U. davidiana and M. amurensis were good in competition status at lower elevation than 1,000m. It is necessary, therefore, that appropriate tending practice should be adopted based on the growth pattern and competition status of each species distributed by site types.

• Clinical and Experimental Pediatrics
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• v.53 no.3
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• pp.300-306
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• 2010

Purpose : Recent changes in the population structure of Korea, such as rapid decline in birth rate and exponential increase in old-aged people, prompted us to prepare a new health improvement program in children and adolescents. Methods : We reviewed current health screenings applied for children and adolescents in Korea and other developed countries. We collected and reviewed population-based data focused on mortality and morbidity, and other health-related statistical data. We generated problem lists in current systems and developed new principles. Results : Current health screening programs for children and adolescents were usually based on laboratory tests, such as blood tests, urinalysis, and radiologic tests. Almost all of these programs lacked evidence based on population data or controlled studies. In most developed countries, laboratory tests are used only very selectively, and they usually focus on primary prevention of diseases and health improvement using anticipatory guidance. In Korea, statistics on mortality and morbidity reveal that diseases related to lifestyle, such as obesity and metabolic syndrome, are increasing in all generations. Conclusion : We recommend a periodic health screening program with anticipatory guidance, which is focused on growth and developmental surveillance in infants and children. We no longer recommend old programs that are based on laboratory and radiologic examinations. School health screening programs should also be changed to meet current health issues, such as developing a healthier lifestyle to minimize risk behaviors—or example, good mental health, balanced nutrition, and more exercise.