• Human Ecology Research
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• v.51 no.5
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• pp.473-481
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• 2013

The purpose of this study was to investigate the moderating effects of a size of the friendship network and quality of friendship on the associations between mutual antipathy and maladjustment. The subjects were 678 fifth- and sixth-grade primary school children who were recruited from a public school in Bucheon City. The Peer Nomination Inventory was used to assess mutual antipathy, peer victimization, social withdrawal, aggression, and the friendship network. The children were given a classroom roster and asked to nominate up to three classmates who fit each description. Additionally, the children reported the quality of their friendships using the Friendship Quality Scale. Each child was asked to indicate his or her one best friend and rate how accurately a sentence describe done of their best friends on the scale. The results revealed that the friendship network and friendship quality significantly moderated the relationships between mutual antipathy and social withdrawal, and peer victimization. The magnitude of the association between mutual antipathy and social withdrawal was not significant for large friendship networks and high quality friendships. Although mutual antipathy was significantly associated with peer victimization, the association was stronger at lower levels than at higher levels of the friendship network and quality. However, there was no moderating effect of the friendship network and quality on the association between mutual antipathy and aggression. A large friendship network and high quality friendship could be protective factors among those who have mutual antipathy in peer groups.

• 한국연소학회:학술대회논문집
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• 2007.05a
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• pp.161-167
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• 2007

Gasification characteristics in the fluidized bed reactor are essential for the design of a gasification furnace to optimize the operation condition. Moisture content of the solid fuel is one of the important factors to influence directly the gasification characteristics. So it is necessary to investigate the effect of moisture content of solid fuel in gasification process. Gasification characteristics are investigated with results from thermogravimetric analyser and lab-scale fluidized bed reactor for wood and RDF samples along with changing moisture contents. Additionally lab-scale fluidized bed reactor was run continuously and gas concentrations at the exit were measured. It is observed that the rate of reaction in partial oxidation condition is in between the results from the combustion environment and from the inert condition. Moisture content in a particle slows down the heating rate of a particle. So, reaction time is delayed by the moisture content. However, RDF samples that are easy to break-up doesn't show the effect of moisture content. The results of continuous operation condition shows that proper moisture content promotes gasification because steam from the particles helps gasifcation of the sold fuel.

• Computers and Concrete
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• v.21 no.4
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• pp.385-397
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• 2018

This study is focused on the investigation for similitude the requirements between prototype and scaled models to determine the structural behavior of concrete load bearing systems. The scaling concept has been utilized in many engineering branches, has been assisted to engineers and scientists for obtain the behavior of the prototype by using scaled model. The scaling can be done for two purposes, either scaling up or scaling down depending upon the application. Because, scaled down models are the experimentation on scaled models is cheaper than huge structures. These models also provide facilities for experimental work. Similarity relationships between systems are created either by field equations of the system or by dimensional analysis. Within this study, similarity relationships were obtained by both methods. The similarity relations obtained are applied to different load bearing systems and it is determined that the similarity relation is a general expression. In this study, as an example, column, frame, cantilever beam and simple beam are chosen and 1/2, 1/5 and 1/10 scales are applied. The results are compared with the analytical results which are obtained by creating of the finite element models with SAP2000 software of different scaled load bearing systems. The analysis results of all systems are examined and it is determined that the scale factors are constant depending on the scale types for different load bearing systems.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.20 no.5
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• pp.67-81
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• 2017

Because of lack of accurate understanding of the mechanism of urban heat island (UHI) phenomenon and lack of scientific discussion, it is hard to come up with effective measures to mitigate UHI phenomenon. This study systematically described the UHI and suggested the solutions using green-infrastructure (green-infra). The factors that control UHI are very diverse: radiant heat flux, latent heat flux, storage heat flux, and artificial heat flux, and the air temperature is formed by the combination effect of radiation, conduction and convection. Green-infra strategies can improve thermal environment by reducing radiant heat flux (the albedo effect, the shade effect), increasing latent heat flux (the evapotranspiration effect), and creating a wind path (cooling air flow). As a result of measurement, green-infra could reduce radiant heat flux as $270W/m^2$ due to shadow effect and produce $170W/m^2$ latent heat flux due to evaporation. Finally, green-infra can be applied differently on the macro(urban) scale and micro scale, therefore, we should plan and design green-infra after the target objects of structures are set.

• Progress in Superconductivity and Cryogenics
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• v.16 no.4
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• pp.62-65
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• 2014

To minimize most heat loss of current lead for high-temperature superconducting (HTS) rotating machine, the choice of conductor properties and lead geometry - such as length, cross section, and cooling surface area - are one of the various significant factors must be selected. Therefore, an optimal lead for large scale of HTS rotating machine has presented before. Not let up with these trends, this paper continues to improve of diminishing heat loss for HTS part according to different model. It also determines the simplification conditions for an evaluation of the main flux flow loss and eddy current loss transient characteristics during charging and discharging period.

• Journal of Environmental Impact Assessment
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• v.22 no.5
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• pp.455-466
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• 2013

The aim of this study is to seek application plans of National Ecosystem Survey database based on comparison and examination of feasible analysis methods for distribution characteristics of alien plants. In order to set up a correlation analysis method between alien plants and environmental factors, we had reviewed the 3rd National Ecosystem Survey guide book and consequently, two kinds of analysis method were tested. One was 1/25,000 scale map boundary based analysis and the other was representative mountain area based analysis. In this study we restricted the research area to select reliable surveyed database from whole "2011 National Ecosystem Survey flora database" according to two major criteria. First, an area defined by 1/25,000 scale map boundary and representative mountain area where the number of surveyed flora records should be within top 20%. Second, land cover map should also be built up inside that area. As a result, 25 map boundaries and 25 representative mountain areas were extracted to be analyzed. To limit a boundary for every representative mountain area we had analyzed distribution of environmental factors around that area by manual inspection with SPOT-5 remote sensed satellite image then designated 3km buffer zone from each alien plant location in that area. After then, naturalized index (NI) and urbanized index (UI) was calculated and correlations analysis was carried out. With the result of correlation analysis by map boundary only agricultural land area showed significant value of r (0.4~0.6, correlated) and the rest of factors did not. In the case of representative mountain area, the result showed that agricultural land, road and forest area showed significant value of r (0.6~0.8, highly correlated) which was corresponding to existing researches. Therefore, representative mountain area based method is preferable when using the alien plants database of National Ecosystem Survey for species distribution analysis. And also, considering the way of database utilization is strongly suggested at the first stage of survey planning for promoting active use of national ecosystem survey database.

• Journal of Korean Foot and Ankle Society
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• v.5 no.2
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• pp.112-119
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• 2001

Purpose: The purpose of this study is to analyze the clinical prognostic factors which may affect the postoperative clinical results of the unstable ankle fractures. Materials and Methods: This study is based on 62 unstable ankle fractures treated by open reduction and internal fixation from May 1994 to June 2000, with a minimum follow-up period of 12 months(range: 13 months-7 years 3 months). The 62 patients were average 39.1 years old with male: female ratio of 41:21. Based on Lauge-Hansen classification, the supination-external rotation type was the most common with 36 (58.1%) cases. The clinical results was assessed by American Orthopaedic Foot and Ankle Society(AOFAS) functional scale. The sex, age, body weight, trauma-operation interval, operation time, cause of injury, fracture type were statistically analyzed as the possible postoperative clinical prognostic factors. Results: Postoperative AOFAS functional scale was average 82.1 points with 22(35.5 %) cases excellent, 12(19.4%) good. 16(25.8%) fair and 12(19.4%) cases poor results. The age and the operation time were found to be statistically significant factors affecting the prognosis(p<0.001). The sex, weight, trauma-operation interval factors did not significantly affect the clinical results. The pronation-external rotation type showed better clinical tendency among the fracture types, but without the statistical significance. Conclusion: The surgically treated unstable ankle fractures in patients whose age was above 41 years old or operation time exceeding 90 minutes showed significantly poor clinical results.

• Journal of Korean Foot and Ankle Society
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• v.9 no.2
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• pp.158-161
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• 2005

Purpose: To analyze the risk factors and the treatment results of the distal chevron osteotomy for the hallux valgus in young adult. Materials and Methods: Eleven cases of hallux valgus in 9 patients who underwent the distal chevron osteotomy between February 2000 and January 2004 were included for the study. For the clinical evaluation, we used hallux-metatarsophalangeal interphalangeal scale of American Orthopaedic Foot and Ankle Society (AOFAS). For radiological evaluation, we measured hallux valgus angle (HVA) and intermetatarsal angle (IMA). Results: Five patients had family history of hallux valgus. Symptoms were aggravated by military drill and sports activity. The average AOFAS scale was 62.5 preoperatively, and 88.4 at final follow-up. The HVA and IMA were $34.9^{\circ}$, and $15.8^{\circ}$ preoperatively, $16.3^{\circ}$ and $8.2^{\circ}$ at postoperative 6 weeks, and $19.9^{\circ}$ and $9.8^{\circ}$ at final follow-up. Conclusion: The symptoms of hallux valgus in young adults were aggravated by military drill and sports activity. Distal chevron osteotomy was useful for the treatment of the moderate to severe hallux valgus in young patients.

• Nuclear Engineering and Technology
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• v.56 no.4
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• pp.1310-1319
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• 2024

The reactor cavity cooling system (RCCS) is a passive reactor safety system commonly present in the designs of High-Temperature Gas-cooled Reactors (HTGR) that removes heat from the reactor pressure vessel by means of natural convection and radiation. It is one of the factors responsible for ensuring that the reactor does not melt down under any plausible accident scenario. For the simulation of accident scenarios, which are transient phenomena unfolding over a span of up to several days, intermediate fidelity methods and system codes must be employed to limit the models' execution time. These models can quantify radiation heat transfer well, but heat transfer caused by natural convection must be quantified with the use of correlations for the heat transfer coefficient. It is difficult to obtain reliable correlations for HTGR RCCS heat transfer coefficients experimentally due to such a system's size. They could, however, be obtained from high-fidelity steady-state simulations of RCCSs. The Rayleigh number in RCCSs is too high for using a Direct Numerical Simulation (DNS) technique; thus, a Reynolds-Averaged Navier-Stokes (RANS) approach must be employed. There are many RANS models, each performing best under different geometry and fluid flow conditions. To find the most suitable one for simulating an RCCS, the RANS models need to be validated. This work benchmarks various RANS models against three experiments performed on the HTTR RCCS Mockup by the Japanese Atomic Energy Agency (JAEA) in 1993. This facility is a 1/6 scale model of a vessel cooling system (VCS) for the High Temperature Engineering Test Reactor (HTTR), which is operated by JAEA. Multiple RANS models were evaluated on a simplified 2d-axisymmetric geometry. They were found to reproduce the experimental temperature profiles with errors of up to 22% for the lowest temperature benchmark and 15% for the higher temperature benchmarks. The results highlight that the pragmatic turbulence models need to be validated for high Rayleigh natural convection-driven flows and improved accordingly, more publicly available experimental data of RCCS resembling experiments is needed and indicate that a 2d-axisymmetric geometry approximation is likely insufficient to capture all the relevant phenomena in RCCS simulations.

• Journal of the Korean Geographical Society
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• v.28 no.1
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• pp.16-39
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• 1993

This study aims to analyze the locational factors which the small firm enterpreneurs in Pusan City mainly consider in deciding location choices for their plants, and then to grasp the differences of the factors in terms of nature of firms, managerial personal characteristics and zoning areas. In order to implement the purpose of the rescarch, data are collected from selected small firm enterpreneurs throughthe questionaire. The main results are summerized as follows. First, it is pointed out that small firm indu-strialists for the regional choice consider crucial rationale as non-economic factor of personal reson with additional consideration of transpor-tation, infrastructure, service, market and labor forces. But in selection of site, they are apt to have high regard on the such factors as infra-structure, service, land and transportation factor. These factors to select the site demonstrate differentiation in terms of character of enter-prises, managerial characteristics and zoning areas. For example, land in the light of indu-strial sector is regarded as an important factor with longer the time of the establishment of firms or more aged or experienced enterpreneurs, wheras infrastructure and service in the heavy and chemical industrial sector are taken up as an important one with shorter the time of establishment of firms or less aged or experienced or higher educational background of enterpren-eurs. In addition, the non-economic factors such as the residential livebility and personal reason are picked up as important factors with smaller the firm or more aged or experienced, lesser educational background of entrepreneurs. Taking into consideration zoning area, infra-structure and service in the industrial area such as the exclusive and semi-industrial areas, land in green belt area, and transportation in the commercial and residential areas are singled out as the most important factors respectively. In addition, the non-economic factors of the resi-dential livability and personal reason in the non-industrial areas are also highly regarded. Second, land is picked up as the most impor-tant one of pulling factors toward the present site while other factors such as infrastructure, service, personal reason are also regarded as the secondary reason for the move-in decision; the pulling factors for the present plant location show somewhat differences in terms of the charcter of the enterprises, managerial chara-cteristics and zoning areas. Policy measures including land, infrastructure under the environmental aspects, service and transportations are, in turn, pointed out as the important ones for pushing factors. Meanwhile, as the important staying factor in the present place, transportation, infrastructure and service under the aspect of the agglomeration benefit, market, personal reason are considered. The pushing and staying factors also shows somewhat distinctive differences in terms of the character of enterprises, managerial chracteristics and zoning area. In the case of zoning area, land is regarded as the most important factor to move out, especially in the non-industrial areas inclu-ding the commerical and residential areas policy measures, infrastructure and service are indicated as important factors to move out. In the mean-time, as the important staying factor, industria-lists in the exclusive and semi-industrial areas point out transportation, infrastructure and service. Whereas the counterparts in the com-mercial area regard transportation and market as important factor, those in the residential area consider the non-economic factors such as personal reason and residential livability. Taking into consideration the result of this analysis, it is identified that the locational chara-cteristics of the intraurban small firm industries are not only associated with the character of enterprises, but also with manager's personal character and the trait of zoning area. Therefore, it seems that the thorough review or examination of enterprises, industrialists' characteristics and zoning areas will have meanin-gful significance in attemption explanation of small firm industries at the intrauban scale in the future. Especially, it appears that the eco-nomic factors such as land, infrastructure, service, transportation, and the non-economic factors such as residential livability and personal reason play together important parts to determine the locational choice of small firm industries along with non-industrial benefit. Thus, such status reveals the obvious implication for the intraurban industrial policy in the future.