• Korean Chemical Engineering Research
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• v.60 no.2
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• pp.267-276
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• 2022

Modelling the energy release performance of energetic material combustion in closed systems is of fundamental importance for aerospace and defense application. In particular, to compensate for the disadvantage of the combustion of single energetic material and maximize the benefits, a method of combusting the mixed energetic materials is used. However, since complicated heat transfer occurs when the energetic material is combusted, it is difficult to theoretically predict the combustion performance. Here, we suggest a theoretical model to estimate the energy release performance of mixed energetic material based on the model for the combustion performance of single energetic material. To confirm the effect of parameters on the model, and to gain insights into the combustion characteristics of the energetic material, we studied parameter analysis on the reaction temperature and the characteristic time scales of energy generation and loss. To validate the model, model predictions for mixed energetic materials are compared to experimental results depending on the amount and type of energetic material. The comparison showed little difference in maximum pressure and the reliability of the model was validated. Finally, we hope that the suggested model can predict the energy release performance of single or mixed energetic material for various types of materials, as well as the energetic materials used for validation.

• Journal of the Korean housing association
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• v.19 no.4
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• pp.11-20
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• 2008

The purpose of this study is to gather baseline data on perceived housing values and satisfaction rates among consumers with the aim of using this information for future planning. Self-administered questionnaires were provided to 1000 university students from Gwangju and the Chonnam area from 2007 October 8th to 30th. The collected data was used to conduct comparative and descriptive statistical analysis: factor analysis, cluster analysis, t-test, $x^2-test$ and one-way ANOVA. The main findings are as follows: Firstly, in relation to perceived house values, students identified three factors as important: pursuit of convenience, disposition toward individuality-orientation and consciousness of others. The respondents regarded convenience as very important, especially in regard to one's safety, health and location of amenities. Secondly, cluster analysis based on perceived house value revealed passive and energetic types. Students in the energetic type exhibited a tendency to prefer convenience, independence, and consciousness of others. Finally in terms of housing satisfaction, the respondents identified four factors as important: house quality, neighborhood environment, local socio-psychological environment, and location. Housing satisfaction was higher among students who lived in large or new houses, shared the same house with their family, and had a room all to themselves. Accoding to these findings, university students important value safety, health and environmental-friendliness in a house and they find location important. Therefore, future houses should reflect these wants.

• Journal of the Korean housing association
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• v.20 no.1
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• pp.1-10
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• 2009

This paper documents research carried on the University students who are potential residents of the city to find out their preference for the ubiquitous residential functions, and categorize based on the life style to find out difference of their preference on ubiquitous residential functions. A survey was conducted on 324 university students in Gwangju city. The students were selected through purposive sampling and quota sampling by self-administered questionnaire sheets. The analysis analyzing methods using SPSS/PC 12.0 are frequency, percentage, factor analysis, cluster analysis, $x^2$(chaisquare)-test and one-way ANOVA (analysis of variance). For the survey, lifestyle types were categorized as: These are classified based on the analysis of facts regarding characteristics of student's lifestyles that are divided into nine types of facts and then make the four types through the cluster analysis as below. Energetic life type, Inactive life type, Family-oriented life type, Thrifty and Personality-oriented life type. The residential function of Ubiquitous is classified as Safety, Convenience, Comfortableness, Information, Health, Leisure and the residential space is divided into bedroom, livingroom, kitchen, bathroom. Considering the preference aspects for Ubiquitous residential function, among the bedroom, living room, kitchen, and bathroom, University student seek for safety from the living room, Convenience from the kitchen and Comfortableness from the living room, bedroom and kitchen. For Information, bedroom is most preferred among the bedroom, living room, and kitchen. For Health and Leisure, bedroom is preferred between bedroom and living room. In terms of the difference about the preferences for ubiquitous functions based on the four types of lifestyles; The Thrift-oriented type is commonly preferred to the Inactive type among the bedroom, living room and kitchen. The Family-oriented and the Thrift-oriented type were preferred to the Energetic and Inactive types in the bathroom. Also, in the entire residential space, the Ubiquitous functions is most preferred by the Thrifty and Personality-oriented life type.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.9
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• pp.136-141
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• 2010

In this paper, after the third electrode type oxidant generator which could format non-uniform electric field in water had been manufactured and installed, by direct electrolysis, the effects of the hydrogen potential and oxidation reduction potential characteristics attendant upon electric field change on a higher concentration oxidant generation characteristics were investigated. Consequently, as the third electrode was installed in the middle of two slit electrodes and the polarity of applied power was changed, it was observed that the third electrode system with the positive electrode can generate a higher concentration oxidant, hydrogen potential and oxidation reduction potential as compared with that of the negative electrode. It is because the positive electrode was bombarded mostly energetic electrons and the negative electrode was bombarded mainly by less energetic positive ions.

• Journal of the Korean Society of Propulsion Engineers
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• v.26 no.4
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• pp.28-43
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• 2022

To minimize such loss due to aging, research on energetic materials is being actively conducted though, there are difficulties in identifying the comprehensive aging mechanisms as they focused on the respective materials. In this study, thermal and surface analysis were performed on energetic materials composed of metals(W, Ti, and Zr) and KClO₄ oxidizer to solve the blind spots of this aging study. It was newly found that the metals in the hygrothermally aged compounds can cause significant changes in performance. For example, the growth in the thickness of the oxide film on the metals led to an increase in the average value of activation energy(E_α). In addition, the standard deviation of E_α tends to dependent on the type of metal, which is due to the difference in electronegativity.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.7
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• pp.1015-1026
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• 2008

The influence of dietary beef tallow (BT) versus sunflower oil (SO) on meat quality and apparent digestibility and deposition of individual fatty acids in the whole carcass was investigated in pigs fed diets containing either BT or SO. The diets contained equal amounts of energy in the form of the variable fats and were fed on an iso-energetic, restricted basis. Crude fat in the SO diet was better digested (p<0.001) than in the BT diet. The dietary fat type had no effect on growth performance, physical properties of the carcass and meat quality. The pigs fed the BT diet showed lower (p<0.001) apparent digestibilities for palmitic and linoleic acid, but those of oleic and ${\alpha}$-linolenic acid were not affected. The ratio of deposition in the carcass to intake of digestible fatty acids for the whole feeding period was decreased (p<0.01) for oleic and linoleic acid in pigs fed the SO diet. The pigs fed the SO diet instead of the BT diet had a lower (p<0.05) deposition:intake ratio for mono-unsaturated fatty acids. The calculated minimum de novo synthesis of saturated fatty acids was increased for the SO diet, but that of mono-unsaturated fatty acids was not different. In conclusion, the iso-energetic replacement of BT by SO had a marked impact on the fatty acid composition of tissues, but did not affect carcass and meat quality traits in spite of the marked difference in the deposition of linoleic acid in adipose tissues, loin muscle and the whole body. In addition, it became clear that the type of dietary fat had marked, specific effects on the synthesis and oxidation of fatty acids.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.52-52
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• 2011

A novel deposition process for n-type nanocrystalline silicon (n-type nc-Si) thin films at room temperature has been developed by adopting the neutral beam assisted chemical vapor deposition (NBa-CVD). During formation of n-type nc-Si thin film by the NBa-CVD process with silicon reflector electrode at room temperature, the energetic particles could induce enhance doping efficiency and crystalline phase in polymorphous-Si thin films without additional heating on substrate; The dark conductivity and substrate temperature of P-doped polymorphous~nano crystalline silicon thin films increased with increasing the reflector bias. The NB energy heating substrate(but lower than $80^{\circ}C$ and increase doping efficiency. This low temperature processed doped nano-crystalline can address key problem in applications from flexible display backplane thin film transistor to flexible solar cell.

• Journal of the Korean institute of surface engineering
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• v.34 no.5
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• pp.516-521
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• 2001

Dry etching of Si wafer and $SiO_2$ layers was performed using He/Cl$_2$ mixture plasma by diode-type reactive ion etcher (RIE) system. For Si etching, the Cl molecules react with the Si molecules on the surface and become chemically stable, indicating that the reactants need energetic ion bombardment. During the ion assisted desorption, energetic ions would damage the photoresist (PR) and produce the bad etch Si-profile. Moreover, we have examined the characteristics of the Cl-Si reaction system, and developed the new fabrication procedures with a $Cl_2$/He mixture for Si and $SiO_2$-etching. The developed novel fabrication procedure allows the RIE to be unexpensive and useful a Si deep etching system. Since the etch rate was proved to increase linearly with fHe and the selectivity of Si to $SiO_2$ etch rate was observed to be inversely proportional to fHe.

• Journal of the Korean Society of Propulsion Engineers
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• v.13 no.1
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• pp.58-71
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• 2009

The blast wave released during the initiation of energetic materials gives rise to pulse energy generation, characterized by a sudden increase of potential energy. A highly efficient energy source, sought from pulse-type lasers, may be utilized in various space propulsion and power applications. This paper introduces a scheme of utilizing the laser energy in 1) attitude control of a satellite requiring of a low thrust, 2) innovative laser-induced drug delivery, 3) implosion-based micro piston development, 4) deflecting and zapping of space debris for laser kill purpose, and 5) finally lunar detection using laser induced breakdown spectroscopy.

• Journal of The Korean Astronomical Society
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• v.37 no.4
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• pp.193-197
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• 2004

Anomalies in the far-infrared [C II] 158 ${\mu}m$ line emission observed in the central one-kiloparsec regions of spiral galaxies are reviewed. Low far-infrared intensity ratios of the [C II] line to the continuum were observed in the center of the Milky Way, because the heating ratio of the gas to the dust is reduced by the soft interstellar radiation field due to late-type stars in the Galactic bulge. In contrast, such low line-to-continuum ratios were not obtained in the center of the nearby spiral M31, in spite of its bright bulge. A comparison with numerical simulations showed that a typical column density of the neutral interstellar medium between illuminating sources at $hv {\~} 1 eV $ is $N_H {\le}10^{21}\;cm^{-2}$ in the region; the medium is translucent for photons sufficiently energetic to heat the grains but not sufficiently energetic to heat the gas. This interpretation is consistent with the combination of the extremely high [C Il]/CO J = 1-0 line intensity ratios and the low recent star-forming activity in the region; the neutral interstellar medium is not sufficiently opaque to protect the species even against the moderately intense incident UV radiation. The above results were unexpected from classical views of the [C II] emission, which was generally considered to trace intense interstellar UV radiation enhanced by active star formation.