• 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.

• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.2
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• pp.50-59
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• 2020

Superabsorbent Polymer (SAP) expands inside concrete by absorbing water and contracts as it discharges water. Through this process, concrete can achieve the internal curing effect, but the space occupied by the expanded SAP remains as a void. In this study, the effects of SAP internal curing and voids were evaluated by evaluating the fundamental properties and chloride penetration resistance of SAP mixed concrete. Also, to evaluate the internal curing effect by SAP, the tests were carried out under water and sealed curing conditions, respectively. From the result, the compressive strength of water curing did not differ significantly according to the mixing ratio of SAP. In the case of sealed curing, however, the compressive strength tended to increase as the mixing ratio of SAP increased. The internal curing effect of sealed curing was considered to have influenced the increase in compressive strength. In the case of the chloride diffusion coefficient, the diffusion coefficient tended to decrease as the mixing ratio of SAP increased. In particular, as the sealed curing is applied, the chloride penetration resistance is further improved due to internal curing effect. If the curing conditions are different, it is considered inappropriate to estimate the chloride penetration resistance by the surface electrical resistivity.

• Journal of Korean Society of Forest Science
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• v.95 no.1
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• pp.45-49
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• 2006

The objective of this study is to offer a basic information to select the plant species for environmentally friendly forest road by quantifying the pull-out strength by 18 species used for a revegetation of forest road slope. In the investigation of the root depth growth during 17 months, Indigobush amorpha showed maximum depth of 34.0 cm and perennial ryegrass showed minimum depth of 17.7 cm among all species. The pull-out strength by herb species was $0.054ton/m^2/plant$ for exotic species, $0.085ton/m^2/plant$ for indigenous species, and by shrub species was $0.049ton/m^2/plant$. There were no large difference among herb species in pull-out strength, but shrub species were approximately 9 times stronger than herb species. Thus, for maximizing tightening effect and use of inner soil space. The mixed seeding using herb for erosion control and shrub for shallow failure protection would make up optimal revegetation of forest road slope.

• Journal of Distribution Research
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• v.12 no.3
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• pp.1-21
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• 2007

This study introduces 'Free Market' that was recently developed in front of Hongik university. 'Free market', as a place for transactions for art products produced by artists or prospective artists, is held regularly every Saturday in front of Hongik university. This study collected data through in-depth interviews with participants and participant observations at the market to analyze the success factors of 'Free Market'. We described development process, unique characteristics of 'Free Market' and new experiential values that the market provide to the participants. This free market was introduced as roadside stand in the middle of 1990s when some artists started selling their works. It passed through the growth stage after it staged the event that had mixed characteristics of 'flee market' and 'art market' at local festivals in 2001. In 2002 Sin-Chon culture forum directedculture-oriented market and the market has been developed as a current 'Free Market'. Recently 'Free Market' is comprised of steps, artists, and customers who voluntarily participated in the market. The market is held regularly every Saturday and provide various types of programs for the participants. Major characteristics of this free market were summarized as 'complex space' and 'role transition', and these characteristics provided the participants new experiential values such as 'freedom', 'emergent experiences', 'social interaction' and 'hero of festivals' through the participant role. We interpret that 'Free Market' has been successfully settled down as a new type of retail store based on these new experiential values. Therefore, this case provides very useful implications that unique experiential values that a store provides to the customers can be major sources of store competitive advantages.

• Journal of Korean Society of Transportation
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• v.23 no.3 s.81
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• pp.35-47
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• 2005

This paper is to review a literature concerning Bus Transit Route Network Design(BTRNDP), to describe a future study direction for a systematic application for the BTRNDP. Since a bus transit uses a fixed route, schedule, stop, therefore an approach methodology is different from that of auto network design problem. An approach methodology for BTRNDP is classified by 8 categories: manual & guideline, market analysis, system analytic model. heuristic model. hybrid model. experienced-based model. simulation-based model. mathematical optimization model. In most previous BTRNDP, objective function is to minimize user and operator costs, and constraints on the total operator cost, fleet size and service frequency are common to several previous approach. Transit trip assignment mostly use multi-path trip assignment. Since the search for optimal solution from a large search space of BTRNDP made up by all possible solutions, the mixed combinatorial problem are usually NP-hard. Therefore, previous researches for the BTRNDP use a sequential design process, which is composed of several design steps as follows: the generation of a candidate route set, the route analysis and evaluation process, the selection process of a optimal route set Future study will focus on a development of detailed OD trip table based on bus stop, systematic transit route network evaluation model. updated transit trip assignment technique and advanced solution search algorithm for BTRNDP.

• Journal of Korean Society of Transportation
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• v.34 no.2
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• pp.191-206
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• 2016

Pedestrian performance measurement has generally used the average values of pedestrian volumes and speeds from a sample, although each individual's pedestrian behavior of the sample is mainly affected by his/her socio-economic and physical characteristics. In particular, if such individual characteristics of the sample have wide variations, the average values are hard to be representative. In this respect, this study found that a platoon of pedestrians had a major effect on their pedestrian flows on sidewalks. The more platoons was mixed on pedestrian roads, the lower pedestrian flow rate was. The indexes such as a pedestrian flow rate and an occupancy space are typically calculated by pedestrian volumes in a given period of time regardless of the existence of a platoon. However, it is plausible that a pedestrian speed and a level of pedestrian congestion can be different under the equal amount of pedestrian volumes. Therefore, this study suggested criteria for determining level of service for pedestrian considering platoon effects and confirmed that two places had different pedestrian LOSs because of the platoon effects, even if they showed the same pedestrian flow rate.

• Journal of the Korean association of regional geographers
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• v.19 no.3
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• pp.454-475
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• 2013

In 2011, Daegu hosted the International Association of Athletics Federation Championships and attempted to use this event strengthen its global profile. Organizers hoped Daegu 2011 would strengthen knowledge about Daegu internationally and help the city overcome recent economic stagnation by bolstering tourism and investment on the global scale. Written from the perspective of a foreigner living in Korea, this interpretive article uses mixed-method cultural geographic analysis to evaluate the momentum Daegu 2011 produced in these directions. The article draws on a tripartite "territorialisation" approach to mega-event tourism's production of space, focusing on representational efforts during the approach to the championships and the event itself. Promotional materials receive particular attention. Interviews with international tourists during 2011 strengthen conclusions drawn from analysis of promotional materials. After reviewing relevant conceptual literature, Daegu's history, and the background of Daegu 2011, the article devotes three subsections to analysis. The first uses critical discourse analysis of a key promotional video to argue that Daegu's self-promotions betrayed insecurity about the city's place within the global tourism market. A second analysis subbsection finds that additional promotional materials did not fully overcome that problem. These materials also produced an overload of Daegu images and aspirations. The third subsection further develops these arguments, pointing to a partial mismatch between images emphasized by promotions and experiences available in the tourism landscape. This subsection also argues that while Daegu 2011 undoubtedly produced positive effects for the city, key challenges remain if Daegu will be placed on the map of globally acknowledged cities.

• Economic and Environmental Geology
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• v.42 no.4
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• pp.301-314
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• 2009

The Taebaeksan mineralized province, which is the most important one in South Korea, is rich in zinc-lead-tungsten-iron-copper-molybdenum-silver-gold mineral resources and has a diversity of deposit styles. These deposits principally coexist in time and space with porphyry-related epigenetic deposit such as skarn, hydrothermal replacement, mesothermal vein, and Carlin-like deposits. The magmatic-hydrothermal systems in the Taebaek fold belt is genetically characterized by the Bulguksa subvolcanic rocks(ca. $110{\sim}50\;Ma$) related to northwestward subduction of the paleo-Pacific Plate. The most important zinc-lead deposits in the area are the Uljin, Yeonhwa II and Shinyemi skarn, the Janggun hydrothermal replacement, and the Yeonhwa I intermediate-mixed (skarn/hydrothermal replacement) ones. In the present study, we present a compilation of metal production and mineral assemblage of the zinc-lead deposits. The metal difference of deposit styles in the area indicates a cooling path from intermediate-sulfidation to low-sulfidation state in the polymetallic hydrothermal system, reflecting spatial proximity to a magmatic source.

• Analytical Science and Technology
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• v.11 no.6
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• pp.485-494
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• 1998

Ternary and quaternary alloys composed of Mo-Ru-Rh-Pd were prepared and their crystal structure and quantitative chemical compositions were analysed by XRD, WDX, EDX and ICP/AES. The results of X-ray diffraction studies showed that the alloys were crystallized in hexagonal close packing, well known as ${\varepsilon}$-phase with $P6_3/mmc$ of space group. The optimum accelerating voltage for Zr~Cd(40~48) analyzed by EPMA using PET crystal was found to be 15 kV and the linear regression coefficient(R) of atomic number and X-ray intensity was approximately 0.998 without Tc standard specimen. The WDX results of alloys of Mo and Pd by linear regression equations were detected to be 0.1% lower compared to WDX analysis results using standard specimen, while Ru, Rh were detected 3% higher. These alloys were completely dissolved in mixed acid of 12.5 mL HCl and 1 mL $HNO_3$, at $220^{\circ}C$ for 22 hours using autoclave with PTFE vessel. There was no reprecipitating phenomnon when diluted 100 times with 1N-HCl. The results of ICP/AES analysis deviated less than 4% comparing with those of normal WDX analysis.

• Science of Emotion and Sensibility
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• v.8 no.3
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• pp.291-301
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• 2005

This study aims to understand causal relationship among preference factors - preferred design, design image, and design elements-to create interaction between artists and spectators, concerning eating and drinking table decoration which is produced with subjective representation chiefly by virtue of the authors' conceptualization and planning. As an experimental research , face-to-face personal interviews have been made in off-line setting through questionnaires. Acquired information from it has been analyzed, which results are as follows. As harmonious, warm, womanish design image, combination of pink-tone similar colors were preferred. As image adjectives highly related with design preference were 'harmonious and inharmonious' A design factor of 'harmonious' was combination of similar colors, while that of 'inharmonious' was association of mixed colors. It has been found that 'colors' have been an important factor among preference design factors. As above, a new concept for design can be established by using data-based information, along with suggesting a direction for preferred design in the field of eating and drinking table decoration. Furthermore, it will be possible to make a study of new preferred design through evaluation of quantitative spectators in this area. It is expected that such researches could give an opportunity to get satisfactory results from newly experimented designs using quantitative data even in a creative design area, as well as table decoration.