• 한국전산유체공학회:학술대회논문집
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• 2001.05a
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• pp.144-148
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• 2001

Characteristics of high temperature rocket nozzle flow is discussed along with the aspects of computational analysis. Three methods of nozzle flow analysis, frozen-equilibrium, shifting-equilibrium and non-equilibrium approaches, were discussed those were coupled with the methods of computational fluid dynamics. A chemical equilibrium code developed for the analysis of general hydrocarbon fuel was coupled with three approaches of nozzle flow analysis, and a test was made for a bell nozzle at typical operation condition. As a results, the characteristics of the approaches were discussed in aspects of rocket performance, thermal analysis and computational efficiency.

• Nuclear Engineering and Technology
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• v.52 no.12
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• pp.2743-2759
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• 2020

A detailed computational fluid dynamics (CFD) simulation analysis model was developed using ANSYS CFX 16.1 and analyzed to simulate the basic design and internal flow characteristics of a 180 MW small modular reactor (SMR) with a natural circulation flow system. To analyze the natural circulation phenomena without a pump for the initial flow generation inside the reactor, the flow characteristics were evaluated for each output assuming various initial powers relative to the critical condition. The eddy phenomenon and the flow imbalance phenomenon at each output were confirmed, and a flow leveling structure under the core was proposed for an optimization of the internal natural circulation flow. In the steady-state analysis, the temperature distribution and heat transfer speed at each position considering an increase in the output power of the core were calculated, and the conceptual design of the SMR had a sufficient thermal margin (31.4 K). A transient model with the output ranging from 0% to 100% was analyzed, and the obtained values were close to the T_hot and T_cold temperature difference value estimated in the conceptual design of the SMR. The K-factor was calculated from the flow analysis data of the CFX model and applied to an analysis model in RELAP5/MOD3.3, the optimal analysis system code for nuclear power plants. The CFX analysis results and RELAP analysis results were evaluated in terms of the internal flow characteristics per core output. The two codes, which model the same nuclear power plant, have different flow analysis schemes but can be used complementarily. In particular, it will be useful to carry out detailed studies of the timing of the steam generator intervention when an SMR is activated. The thermal and hydraulic characteristics of the models that applied porous media to the core & steam generators and the models that embodied the entire detail shape were compared and analyzed. Although there were differences in the ability to analyze detailed flow characteristics at some low powers, it was confirmed that there was no significant difference in the thermal hydraulic characteristics' analysis of the SMR system's conceptual design.

• Journal of the Korean Society of Clothing and Textiles
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• v.33 no.7
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• pp.1164-1179
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• 2009

This study presented the characteristics of a mobile fashion shopping mall as perceived by those in charge of fashion brands, clarified the effect of the characteristics on the intention 'Of introduction, and indicated the differences in the intention of introduction according to the characteristics of brands. This study surveyed individuals in charge of fashion & clothing brands. It utilized SPSS 12.0 program for data analysis and performed frequency analysis, validity analysis, reliability analysis, multi regression analysis, ANOVA, and hierarchical adjustment regression analysis. A summary of the results of this study are as follows: First, the results of the factor analysis are shown to clarify the characteristics of mobile fashion shopping mall; four factors such as facility/usefulness, instant accessibility, personalization, and playfulness were also represented. Second, it showed that facility/usefulness, instant accessibility and personalization generate a positive influence on the intention of introduction. Of the factors, facility/usefulness displayed the highest influence. Third, regarding the effect of the characteristics of a mobile fashion shopping mall on the intention of introduction according to the characteristics of brands (in the case of women's wear) the intention of introduction is strong as instant accessibility and facility/usefulness is highly recognized. Lastly, there is a difference in the intention of introduction according to the characteristics of brands. According to items, casual wear shows the highest intention of introduction as followed by women's wear and sportswear. According to age, brands targeting a 24-29 year old group show a higher intention. Companies with average sales of 50 billion won to 750 billion won (or more) for three years showed a high intention. In addition, the possibility of introduction as a new distribution line was investigated.

• Journal of the Korean Society of Food Culture
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• v.31 no.1
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• pp.105-110
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• 2016

The objective of this study was to determine sensory profiles of rice confections. The samples used in this study obtained from Korea (traditional Korea rice snack and local specialty rice snack) and three countries (USA, Japan, and China) were evaluated and compared. The sensory characteristics of five kinds of rice confections were evaluated using a sensory test and were analyzed via quantitative description analysis (QDA), principal component analysis (PCA), and hierarchical cluster analysis (HCA). In the descriptive analysis, 10 trained panelists evaluated sensory characteristics consisting of 19 attributes, and there were significant differences (p<0.05) among the 16 characteristics. For the descriptive data, multivariate analysis of variance was carried out and identified differences among the samples. The PCA of rice confections for the first two principal components could explain 85.66% of the variations. The Korean, Japanese, and Chinese rice confections were savory, gritty, and particle-sized, the other Korean local specialty rice confections were fruity, sweet, honey-flavored, compact, and crispy, and those from the USA were glossy, grainy, bright, adhesive, cohesive, crispy, and sweet.

• Journal of the Korean Society of Costume
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• v.60 no.10
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• pp.16-27
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• 2010

Business Casual has been launched because of 'Friday Wear' in the 1990s and in Korea, the business casual has been settled under the influence of the five-day work week. The idea of business casual is that 'Business' and 'Casual wear' are combined. It is the attire that people should wear the jacket for formality and people can wear both on or off duty. As a result of the analysis, based on this, of the characteristics of men's business casual appeared in Seoul collections from 2009 till now, they can be classified in 'Classic & Traditional business casual', 'Modern business casual', 'Natural business casual', 'Feminine business casual' and 'Sporty business casual'. As a result of the analysis of the design characteristics of the Korean men's business casual and the trend, based on the content of the analysis of Seoul Collection, 'Classical Classic & the Traditional', 'Modern of the Contemporary design', 'Natural of the Natural design' and 'the Sporty business casual of the Separate Coordination' including jeans, have presented themselves. Also, as a result of the analysis of Korean business men's business casual according to the classification of the design characteristics in Chapter III, 'Classic & Traditional business casual' account for the majority and then 'Sporty', 'Modern' and 'Natural business casual' account for the rest in order. 'Feminine business casual' hasn't presented itself. As a result of the comparative analysis of the design characteristics in Chapter III & IV, Korean business men's business casual has been concentrated on 'Classical & Traditional' and the design characteristics have not appeared in variety. There has been no such audacious attempt, and items, the characteristics of coordination, colors and materials are not in variety compared to the collection. Meanwhile, as a result of the subsistent characteristics of Koran business men's business casual, the characteristics of business men's business casual can be said to represent themselves in "Separate Coordination with the previous items of formal suits".

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.3
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• pp.398-405
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• 2018

LLC resonant converter is popular with industrial fields because it can be achieved high efficiency by zero voltage switching (ZVS). As interest grew, analysis of characteristics in LLC resonant converter have been actively studied. Generally, characteristic of LLC resonant converter is analyzed based on first harmonic approximation(FHA). The FHA analysis represents the characteristics of LLC resonant converter by obtaining the series resonant operation. FHA analysis of LLC resonant converter in load condition is correct. but it is not correct in no load condition. This paper proposed analysis of characteristics considering the parasitic components to overcome the limitation of FHA and analyze no-load characteristics. The validity of the proposed method has been investigated by simulation and experimental results.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.3
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• pp.1039-1044
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• 2011

Magnetron is applied in microwave ovens for generating microwaves. It is composed of r-fin, yoke, A/F seals, gasket base, filter box. The temperature is occurred highly, when magnetron operate in its systems. Therefore the thermal characteristics must be considered in the design of magnetron. Because of its geometric complex, it is difficult to analysis the thermal characteristics. In this paper, temperature analysis is performed for all components. The commercial software ANSYS is used to consider both conduction and convection. The analysis is carried out by adding each component. An experiment on the thermal characteristics is performed to verify the reliability for simulation.

• Proceedings of the KIEE Conference
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• 1997.07a
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• pp.230-233
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• 1997

In this study, design and analysis of 3-phase induction moter are as follows. - Motor characteristics analysis by equivalent circuit ${\cdot}$ Motor characteristics analysis according to variation of rotor slot-tip ${\cdot}$ Motor characteristics analysis according to variation of rotor slot-mouse ${\cdot}$ Motor characteristics analysis according to variation of rotor slot-opening

• 전기의세계
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• v.21 no.2
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• pp.9-19
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• 1972

The transient characteristics of separately excited d-c motor driven by thyristor d-c chopper is studied in this paper. The armature controlled system is applied. As a result of theoretrical analysis the following conculsions were drawn: (1) For the transient analysis, it is recognized that the state transition analysis is a more general method and powerful tool than the state equation method or signal flow graph method, although it includes iterative matrix calculations. And the system is dealt with a finite width sampled-data system in the state transition analysis. (2) The transient characteristics of the motor angular velocity and its torque to the sampling duration variation are compared with those due to the amplitude variation of d-c chopper voltage as follows. The attenuation rate of the transient characteristics is equal in both cases, but the initial value of the transient characteristics in former case is greater than in latter case. (3) The roots of characteristics equation of the system lie inside the unit circle of the Z-plane. Therefor the system is stable. Further it is found that as the sampling duration is decreased the relative stability is lessened.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.19 no.5
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• pp.491-498
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• 2009

This paper deals with structural analysis and vibration characteristics of scaffolding structures with a hoist according to payloads. In order to analyze the vibrational and structural characteristics for 20-step scaffolding structure, structural and vibrational characteristics for 2-step scaffolding structure were compared with some experimental results. The numerical results for natural frequencies of scaffolding structures have a good agreement with experimental ones. Through the numerical analysis, firstly, it is shown that the maximum stress of scaffolding structures is lower than von-mises yield criteria when four persons with total weight of 280 kgf are working at the top of the scaffolding structures. Secondly, vibration characteristics including natural frequencies and modes for scaffolding structures are shown in case of various kinds of moving masses.