• Journal of the Korean Electrochemical Society
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• v.11 no.4
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• pp.268-272
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• 2008

$LiFePO_4$ material was synthesized by electrospinning method to obtain optimal particle size($50{\sim}100\;nm$) without carbon coating or ball milling. This material showed an orthorthombic structure with Pnma space group without any impurities, such as FeP or $Fe_2P$, in the XRD pattern. The particle morphology and particle shape were observed by SEM analysis. Li/$LiFePO_4$ cell showed a high initial discharge capacity of 135 mAh/g, at current density of $0.1\;mA/cm^2$ with a cut-off voltage of 2.8 to 4.0V. This cell exhibited a perfect cycle performance over 99.9% cycle retention rate up to 50 cycles.

• Journal of the Economic Geographical Society of Korea
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• v.1 no.2
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• pp.85-102
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• 1998

The Changing Characteristics of Office Location in Central Seoul In recent years, central Seoul has been experiencing a dynamic transformation. In the process of reorganization of urban industrial structure including tertiarization and quaternarization of the economic base of Seoul, business services are growing very rapidly and large scale urban renewal projects are agilely implemented. Downtown office activities become a nucleus for economic performance of Seoul and high-rise office buildings steer the landscape transformation of central Seoul. Even though there appear to exist some evidences that office districts have dispersed to several subcenters, major office activities are still concentrated in the central Seoul. This paper redefines office industry in a narrow meaning comprising only relevant economic sectors and office buildings as office activity-functioning units. It then explores the industrial networking and territorial specialization of office activities focusing on the dual process of concentration and dispersion in Seoul. The changing characteristics of the downtown linkages of office activities in this post-industrial era transforms the spatial economy of central Seoul into more flexible and volatile, while territorial concentration of power and control functions are fortified at the same time. Finally, the paper addresses the development of manufacturing-tertiary-quaternary industrial complex, which can be regarded as new industrial clusters, selling cultural economy of urban space and possessing placeness or images for clients and customers, in relation to urban competitiveness and territorial specialization of large metropolitan areas.

• Journal of the Economic Geographical Society of Korea
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• v.13 no.3
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• pp.398-415
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• 2010

The purpose of this paper is to grasp levels of cost burden in pollution treatment by measuring efficiencies and shadow prices by pollutants in Korean cities. The efficiencies and shadow prices of pollutants will be compared for cities divided by Seoul metropolitan area and non-Seoul metropolitan area. Annual shadow prices of NOx, SOx, and PM10 emissions in the cities of Seoul metropolitan area are 0.846, 0.318, 0.816, respectively for 1999-2005. The annual shadow prices in the cities of Non-Seoul metropolitan area are 0.848, 0.272, and 0.789, respectively over the same periods. The shadow prices of SOx showed similar levels between two areas but those of NOx and PM10 of cities in Seoul metropolitan area were higher. NOx emission quantities of both areas have similar increasing patterns because the NOx has mainly increased with augmentation of transportation regardless of Seoul metropolitan and non-Seoul metropolitan areas. It seems that the reason the shadow prices of two pollutants for the cities of Seoul metropolitan area are higher, is because environmental regulation is stronger in the cities of Seoul metropolitan area, the cities of Seoul metropolitan relatively show higher quantities of pollution reduction under given desirable outputs, and generally have industrial sectors with small pollution emission. In the future we need to reduce pollutants in the various respects such as adjustment of overall industry structure, energy consumption pattern, and reviews of arrangement of living space for the cities located on the downward-sloping segment of production frontier.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.3A
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• pp.189-198
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• 2011

Although high strength bolts with tensile strength of 1,000 MPa are mainly used in steel structure construction sites throughout the world, new high strength bolts are required owing to the installation of continuous long-span bridges resulting from the development and distribution of high strength steel and ultra-thick steel plates. Currently, high strength bolts with tensile strength of 1,300 MPa are being used. However, as they tend to place a large load on a small section of space, a high strength bolt of high structural performance and screw thread shape with less stress concentration is thought to be more effective. This study conducted analyses in order to develop an improved screw thread shape relative to the KS screw thread shape. A new screw thread shape with less stress concentration and effective load distribution at the time of fastening bolts and nuts was provided upon analysis of the characteristics of screw thread shape. Additionally, in an experimental study, the structural performance of high strength bolts with tensile strength of 1,300 MPa was investigated. The results revealed that the new screw thread shape was more effective than the existing screw thread shape in terms of structural performance and mitigating the stress concentration.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.1D
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• pp.91-98
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• 2011

Recently, the usage of elastic paving using EPDM Chip instead of pedestrian sidewalk blocks or permeable concrete used mostly for pedestrian walk, trails and in parks has been increassed as it can absorb impact during walking and produce wide range of colors and designs. However, the properties of EPDM Chip including elasticity and durability are decreased when exposed to ultraviolet ray and scenic paving functions through various colors are lowered due to the yellowing phenomenon. In this study, ultraviolet ray accelerated weathering test has been conducted to analyze the color changes in EPDM Chip and polyurethane resin, which are the main ingredients of elastic paving, when exposed to ultraviolet ray. The color differences are quantitatively analyzed through the color value coordination of the colored space by using the color difference scheme. The experimental results show that the color changes in BL polyurethane resin which is used most frequently at present was larger than that of EPDM Chip. Moreover, the total color difference, ${\Delta}E$, of BC polyurethane resin are 3.162 on the $14^{th}$ day of commencement of acceleration, which is 6 times greater color change resistance against ultraviolet ray than that of BL polyurethane resin with total color difference of 20.639. Therefore, the usage of BC polyurethane resin, which is manufactured to have chain-type molecular structure by using the isocyanate as the HMDI at the time of producing polymer, as binder in elastic paving with EPDM Chip is found to be a highly efficient method of restraining the color changes due to the ultraviolet ray.

• Journal of the Korean Society of Costume
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• v.62 no.3
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• pp.137-151
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• 2012

In 1966, $Seokgatap$ pagoda in $Bulguksa$ temple was damaged by the tomb robbers and was dismantled to fix the damage. In the process, many offerings to Buddha and containers for Sarira(the cremated remains) were found in $Sarigong$(specially designated space for the Sarira casket) inside the second floor of the pagoda. Many fabrics like $Geum$, $Neung$(twill), $Rha$(complex gauze), silk tabby and linen were also excavated. In this study, $Geum$ fabric from the $Seokgatap$ was closely examined. $Geum$ of $seokgatap$ is weft-faced compound weave according to the analysis of its weaving pattern which was wrongly presumed as warp-faced compound weave for some time. Technical analysis of $Geum$: Main: silk, Binding: silk, Proportion: 1 main warp to 1 binding warp, Count: 15 main warps and 15 binding warps per centimeter, Weft: polychrome silk without apparent twist, Colors: yellow, mustard yellow, deep blue, green and purple, Weave: weft-faced compound twill, 1/2 S. $Geum$ of $Seokgatap$ was made in the $8^{th}$ century, since it was weaved in weft-faced compound weave twill which was popular in the $8-9^{th}$ century. And also, the arrangement of the colors was done in the same way of gradation $Geum$ silk which was popular in the $7-8^{th}$ C in China and Japan. Third, we restored the pattern of $Geum$ of the Unified Shilla Dynasty for the first time. It was very difficult to figure out the shape and the size of pattern since the fabric was partially lost and ruined. We tried to draw the diagram of structure with the cross point of the warp and the weft to restore the pattern. By doing so, we could identify two kinds of small flower pattern, palmette and the pattern of repeating vines. Fourth, we could infer that the $Geum$ of $Seokgatap$ was used for $geumdae$(a pouch made of $geum$) by analyzing all the documents and the characteristics of the fabric.

• Journal of the Korean Solar Energy Society
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• v.34 no.4
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• pp.57-65
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• 2014

In order to reduce greenhouse gas emissions in recent agricultural energy and increase the energy self-sufficiency rate of each farmer, it is extremely important to expand the supply of solar energy using unused space of agricultural facilities, roof. This study surveyed and analyzed the environmental and administrative factors such as problems according to the structure, azimuth and latitude of broiler houses and stability of standard broiler houses required to use broiler house roof based on the poultry houses in Sangju-si. The results can be summarized as follows: 55.6% of the solar energy facilities of according to the classification of arable lands of broiler houses were available, and 31.7% of them were available by classifying according to the azimuth. However, 20.6% of them were available in the survey considering all the arable land and azimuth. In the roof inclination of the broiler houses, from 20 to $25^{\circ}$ was the most common, 30 broiler houses. The broiler houses with the roof inclination more than $20^{\circ}$ accounted for 63% of the total. It was considered that the inclination was generally proper. In the structural safety, only 3 broiler houses that were constructed as a standard broiler house were available. In practice, all but one broiler house was inappropriate to expand the solar energy project using roof. The solar thermal facility weighed $63.6kg/m^2$ in total: the frame and solar thermal collector weighed $27.8kg/m^2$ and $35.8kg/m^2$, respectively. The standard broiler house required to be internally reinforced. This study suggested a plan for internal reinforcement and a feasible plan because there were problems with structural safety when installing solar thermal and photovoltaic systems.

• Journal of the Korean Magnetics Society
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• v.15 no.3
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• pp.167-171
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• 2005

Detailed aspects of the charge disproportionation (CD) transition for a polycrystalline $La_{1/3}Sr_{2/3}FeO_{2.96}$ were studied with the X-ray diffraction, $M\ddot{o}ssbauer$ spectroscopy, and SQUID magnetometer. The crystal structure was found to be rhombohedral with a space group R/3c. The lattice parameters were $a_R=5.4874\;\AA,\;and\;a_R=60.07^{\circ}$, respectively. $M\ddot{o}ssbauer$ spectra were taken within a wide range of temperature from 4.2 K up to room temperature. In the low temperature region, the spectra were comprised of two superimposed sextets which originated from $Fe^{3+}\;and\;Fe^{5+}$, respectively. This was the antiferromagnetic mixed valence state produced by the charges disproportionated into two different species. In the high temperature region, however, only a singlet from $Fe^{3.6+}$ was observed, indicating that it was a paramagnetic averaged valence state. The CD transition occurred in the temperature range from 175 K to 200 K, in which the two phases coexisted. The origin for the CD transition was explained by the thermally generated fast hopping of electrons. Hysteresis loop showed that there existed a strong antiferromagnetic interaction among magnetic ions. As the temperature increased thru the CD transition temperature, it was very likely that the interaction between $Fe^{3+}\;and\;Fe^{5+}$ was replaced by a more stronger one.

• Korean Journal of Plant Resources
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• v.9 no.1
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• pp.11-21
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• 1996

This study has observed the development, structure and distribution of oil canals in mitsuba, seri, ashitaba and hamabohu, that are condiment herbs belonging to the Umbelliferae family, using a light microscope. Oil canals were found in the petioles, leaf blades, stems, roots, hypocotyls and cotyledons. Oil classified into distribution due to ring vascular bundles, as in mitsuba and seri, and distribution due to diffuse vascular bundles, as in ashitaba and hamabohu. Oil canal development in the cortex due to petiole thickening was followed by the development of collenchyma and vascular bundles. However, no vascular bundles were formed in some cases. Many oil canals were found in the periphery of the petioles. Oil canals in leaf blades were found on the adaxial and abaxial sides on the veins. Those around the main veins were larger. Steam oil canals were found in the cortex and pith in mitsuba and seri, and in the cortex and fundamental tissues around the xylem, in ashitaba and hamabohu, while those in the roots were found in the pericycle in mitsuba and seri, and in the collenchyma-like tissues and phloem in ashitaba and hamabohu. The transverse sections of oil canals were round or elliptical. The secretory cells in the cortex and pith were smaller than the neighboring parenchyma cells, while they were larger than the neighboring parenchyma cells in the phloem.

• Journal of the Korean Geophysical Society
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• v.4 no.2
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• pp.103-111
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• 2001

Geophysical survey was carried out to derive some information on the existence of near-surface anomalous body at Reung-Chi area in Kongju. Resistivity, seismic, magnetic and gravity method were applied. Geophysical survey that was applied was the electrical resistivity survey, seismic survey, magnetic survey, gravity survey. These surveys are analyzed to provide data of high resolution. As a result of analysis of resistivity survey, anomalies showing high resistivity anomaly than around appeared, and the one showing M-shape out of those explains the possibility that underground common or other underground structure or geographical anomalous zone could exist in the underground. As a result of analysis of seismic survey, it is clear that the low velocity layer is spread as far as the bottom of the underground. It is possible to presume that it is a phenomenon appearing while going through the underground space where it is lying in the underground. Area that shows unusual situation in interpretation of data on seismic waves are included into the area that once showed resistivity anomaly, the results of both seismic surveys come in accord. As a result of magnetic survey, a circle-shape of twin magnetic fields in the area where abnormalities are shown between electrical resistivity survey and seismic survey is appeared. Given the area of gravity survey, abnormalities whose density is different from the one around the bottom of the underground. As a result of analogizing the data of underground of the subsurface based on analysis of data from each survey, it was interpreted that anomalous zone exists commonly in the research areas.