• Journal of the Korean Institute of Gas
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• v.11 no.4
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• pp.12-16
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• 2007

The fuel pressure regulator mounted on CNG vehicles is used to maintain a constant pressure in the fuel injection system. It needs precise fuel pressure control to obtain benefits of high efficiency and low emissions in CNG vehicles. In this study, a high pressure test rig for the performance evaluation of CNG regulators was introduced. Two different CNG regulators were tested and compared each other at various test conditions. Results showed that dynamic response and creep characteristics are directly effected by the valve assembly design. Gas temperature was dramatically dropped at hish supply pressure conditions, so that effective design for coolant bowl is needed to prevent icing problem.

• Proceedings of the SAREK Conference
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• 2007.11a
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• pp.416-422
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• 2007

The application analysis of bubble pump on the domestic solar water heater system is presented. The system investigated in this study is a passive device, self pumping and self regulating. It was test to use the bubble pump on solar water heater system. The test experiment has been taken on the existed vacuum tube about the efficiency, working fluid temperature and pressure and circulated power. In order to check the working temperature and working pressure effectively, the bubble pump was test separated from the solar water heater. The equipment consists of the bubble pump, heater and heat exchanger. The main structure of bubble pump was design depend on the character of two phase flow. The complete system was instrumented to measure pressures, temperatures and their relationship with the solar radiation intensity. The theory analysis of design bubble pump has been given and the experiment result analysis has been included in the paper.

• Journal of the Korean Society of Safety
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• v.27 no.6
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• pp.99-108
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• 2012

Ultra High Performance Concrete(UHPC) has compressive strength higher than 180 MPa. The use of steel fibers in the dense UHPC matrix increases tensile strength, ductility and bond strength between UHPC and rebars. However, to apply the advance material behavior of UHPC to the design of a structure, we need design formulas. The crack formula is one of them. This paper investigated experimentally the bond behavior of a rebar and K-UHPC, the UHPC developed by Korea Institute of Construction Technology, and, modified CEB-FIP crack formula based on the test. In addition, this paper tested the crack behavior of K-UHPC reinforced with rebars to verify the modified crack formula. The result showed that the modified formula is reasonable to predict the width of cracks in the reinforced K-UHPC structures.

• Food Science and Preservation
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• v.11 no.1
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• pp.12-16
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• 2004

This study was to investigate the preference test of among 10’s and 20’s in New York, Atlanta, Chicago and Sanfrancisco in USA. Preference of packaging, design, printing, flavor, texture and overall preference surveyed. About thirty percent of the respondents showed high score in packaging among the items. The design and color of Yukwa was 22.0％ and 24.1％ in “excellent”. American did not prefer the texture due to stickiness of Yukwa. However, 92.7％ of the respondents showed high score in overall acceptability of Yukwa. On the basis of this result Yukwa would he developed for residential people’s preference. It is possible to export successfully the Korean traditional snack, Yukwa.

• The Journal of the Korea Contents Association
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• v.19 no.7
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• pp.291-303
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• 2019

For cities with ancient buildings at core areas, night lighting is an effective means to demonstrate their history and culture. In this regard, night scenes of these ancient buildings are evaluated from multiple aspects, such as color rendition, brightness ratio affected by ambient light and technological realization of lighting facilities. This study builds a visual evaluation system for night scenes of ancient buildings based on three dimensions, namely ancient architecture carrier performance, visual perception and technological realization, and explains specific evaluation sub-criteria one by one. In addition, this study adopts Analytic Hierarchy Process (AHP) to analyze the impact of each sub-criteria item on the weight of the whole evaluation system, and conducts a consistency test to show that the evaluation system meets the reasonable requirements of hierarchy setting. Moreover, relative importance of each sub-criteria item may be determined based on their corresponding weights.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1358-1362
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• 2005

The Ni-base superalloy GTD-111DS was designed in the 1970s and is widely used as the material of the first stage blade under a severe combination of temperature and pressure in gas turbines. But because GTD-111DS is distributed in the shape of blade and blade has a unique figure and many cooling channels, it is hard to manufacture the test specimen. In this reason, there are little data on the microstructure and mechanical properties of the alloy. Therefore through the microstructure analysis, present paper observed that the shape of $\gamma{'}$ did not change even if aging time was increased but the amount and volume of the deposition of secondary $\gamma{'}\;rose\;and\;secondary\;\gamma{'}\;grew\;among\;primary\;\gamma{'}$. Also, by tensile test for different temperature, there was difference between yield strength and tensile strength in room temperature on heat treatment and extracting region but the more increasing temperature, the more decreasing difference between yield strength and tensile strength.

• Nuclear Engineering and Technology
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• v.38 no.1
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• pp.45-60
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• 2006

Presently, the VHTGR (Very High Temperature Gas-cooled Reactor) is considered the most attractive candidate for a GEN-IV reactor to produce hydrogen, which will be a key resource for future energy production. A new concept for a reactor cavity cooling system (RCCS), a critical safety feature in the VHTGR, is proposed in the present study. The proposed RCCS consists of passive water pool and active air cooling systems. These are employed to overcome the poor cooling capability of the air-cooled RCCS and the complex cavity structures of the water-cooled RCCS. In order to estimate the licensibility of the proposed design, its performance and integrity were tested experimentally with a reduced-scale mock-up facility, as well as with a separate-effect test facility (SET) for the 1/4 water pool of the RCCS-SNU to examine the heat transfer and pressure drop and code capability. This paper presents the test results for SET and validation of MARS-GCR, a system code for the safety analysis of a HTGR. In addition, CFX5.7, a computational fluid dynamics code, was also used for the code-to-code benchmark of MARS-GCR. From the present experimental and numerical studies, the efficacy of MARS-GCR in application to determining the optimal design of complicated systems such as a RCCS and evaluation of their feasibility has been validated.

• Journal of the Korea Fashion and Costume Design Association
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• v.22 no.1
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• pp.85-96
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• 2020

The purposes of this study were to segment male and female college students on the basis of sneakers' benefits and purchasing behaviors of each market segment. The research method was conducting a survey of 408 male and female college students in Seoul, Gyeonggi-do, Gwangju and Jeollanam-do province. The data were analyzed by Cronbach's α, factor analysis, cluster analysis, χ² test, ANOVA, and Duncan test. The results were as follows. First, they were segmented into 4 consumer types(positive benefits, economy/ personality, fashion/famous brand pursuit, and an unconcerned group) by the benefit of sneakers. Second, the evaluation criteria of the products were significantly different depending on each sub-group in terms of the type and quality of material, weight, colors, design, brand, elegance, fashion trend, and coordination. In the case of purchasing information, the sources of sneakers showed significant differences according to the sub-group in all factors except for the past shopping experience. All types of stores and styles were significantly different depending on the sub-group. Therefore, the results of this study supported that benefit segmentation in sneakers can be useful as an effective variable for evaluating market segmentation.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.776-781
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• 2008

A ground heat exchanger in a GSHP system is an important unit that determines the thermal performance of a system and its initial cost. The Size and performance of this heat exchanger is highly dependent on the thermal properties. A proper design requires certain site-specific parameters, most importantly the ground effective thermal conductivity, the borehole thermal resistance and the undisturbed ground temperature. This paper is part of a research project aiming at constructing a database of these site-specific properties, especially ground effective thermal conductivity. The objective was to develop and evaluation method, and to provide this knowledge to design engineers. To achieve these goals, thermal response tests were conducted using a testing device at nearly 150 locations in Korea. The in-situ thermal response is the temperature development over time when a known heating load imposed, e.g. by circulating a heat carrier fluid through the test exchangers. The line-source model was then applied to the response test data because of its simplicity. From the data analysis, the range of ground effective thermal conductivity at various sites is $1.5{\sim}4.0\;W$/mK. The results also show that the ground effective thermal conductivity varies with grouting materials as well as regional geological conditions and groundwater flow.

• Journal of Korean Association for Spatial Structures
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• v.11 no.4
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• pp.101-108
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• 2011

Glass Reinforced Plastic(GRP) shows very high strength, comparing to the lightness of material. And the effect of transparency or semitransparency can be obtained by this material. However, due to the hand laminating for the GRP, the material properties can not be credible. Thus, the material test of GRP must be performed before the structural design. In this paper, material tests were performed for the design of the artistic column with 30m high and 4mm thickness. And the results of tests could be compared with DIN to evaluate the material properties for the application on the column.