• Journal of Aerospace System Engineering
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• v.14 no.3
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• pp.24-31
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• 2020

A study on the H2O2 based low toxic hypergolic propellant was conducted. The fuel candidates were chosen as a mixture of Amine solvent and reactive additive. The analytical performance was calculated via the NASA CEA code and 96% Isp of the NTO/UDMH was confirmed. The ignition delay measurement with drop test was performed and all candidates showed less than 10 ms in the best performance cases. Based on these results, the feasibility of high response H2O2 based low toxic hypergolic propellant was confirmed.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.5
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• pp.1246-1252
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• 1993

Coal-Water slurry (CWS) is a new potential form of fuel for use in power plants and industrial furnaces. The evaporation and ignition characteristics of CWS have been studied in the post-flame region generated by a flat flame burner. Individual droplets with initial diameters of 1-3mm were supported around the thermocouples and raidly exposed to a hot gas stream. The gas temperature ranged between $950^{\circ}C$ and 1600.deg. C at atmospheric pressure. The effect of droplet size, gas temperature and radiative heat transfer by screen were studied experimentally. The ignition criterion was either a rapid temperature rise in time-temperatuire curves or onset of visible flame in experiment. Incresing the gas temperature or decreasing the droplet size reduced the time required for evaporation and ignition.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.04a
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• pp.351-355
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• 2011

In this study, 2 kinds of HTPE insensitive propellants composed of HTPE/BuNENA binder, AP, AN and Al were investigated for combustion characteristics, ignition delay time, sensitivity and insensitive properties compared with HTPB propellant. HTPE propellant showed almost same sensitivity results as HTPB propellant, showed 2~3 times higher value than the value of HTPB propellant, ignition delay time respectively, and met the standard criteria, while HTPB propellant failed.

• Journal of the Korean Institute of Telematics and Electronics
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• v.17 no.5
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• pp.15-21
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• 1980

An engine control system in which the conventional mechanical ignition system is studied. The contact point of the breaker is replaced by the contactless magnetic pick up sensor from which the information of the speed and the position of the crankshaft is extracted , and further an electronic High Energy Ignitim System Is designed, implemented and tested . The High Energy Igniticwl System increases the secondary spark voltage of the ignition coil from the conventional 10000~15000 volts to the 30000~40000 volts resulting in improving the combustion efficiency. Also, instead of the conventional advimce mechanism forigniliontiming control, a microprocessorbased timinng mechanisn is installed to determine the ignition timing data in response to the engine rpm and the intake manifold vacuum.

• Journal of the Korean Institute of Gas
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• v.21 no.5
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• pp.70-76
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• 2017

The standards related to the "Urban Gas Business Act" and the "Safety Control and Business Regulation of Liquefied Petroleum Gas Act" prescribe the separation distance between gas piping joint excluding welded joints and electric equipments(electric switch, watt meter, breaker, connector, etc). The "Korea Electro technical Regulation" also prescribes the distance between gas piping joints and electric equipments in accordance with the gas related standards. In case of the standards related to the "Urban Gas Business Act", the distance criteria stipulated in the standard of supplying facilities are different from those stipulated in the standard of using facilities. In this study, we have conducted pilot test on the possible ignition distance from the piping joint when LP gas is leaked from the point. We have also examined the adequacy of current standards on the separation distance between gas piping joint and electric equipments. As a result of the tests, we have found that ignition is able to occur at a distance of 30 cm as stipulated in the current standards or more when LP gas is leaked from the joint of the pipe. Therefore, we have made a decision that the criteria for separation distance between gas piping joint and electric equipment specified in the current standards related to the "Urban Gas Business Act" and the "Safety Control and Business Regulation of Liquefied Petroleum Gas Act" is appropriate.

• Korean Journal of Culture and Social Issue
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• v.21 no.1
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• pp.67-96
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• 2015

Do cultural differences affect moral decisions? Two studies were conducted to investigate whether attitudes of individualism vs. collectivism have an impact on ethical decision making. Study 1 (N=92) showed that utilitarianism was preferred in a situation, in which an intervention resulted in the best outcome (i.e., saving more people's lives), while deontology was preferred in a situation, in which the focus was on negative consequences of the intervention (i.e. personal sacrifices). Additionally, there were differences between the idiocentrics and the allocentrics groups regarding morality aspects. In the idiocentrics group, harm and fairness were regarded as more important than other moral aspects, while in the allocentrics group, not only harm and fairness, but also ingroup and authority were perceived as critical moral aspects. In Study 2 (N=30), after lexical decision tasks were conducted for culture priming, the mouse tracking method was used to explore response dynamics of moral decision processes, while judging appropriateness of interventions in moral dilemmas. In Study 2, in a condition, in which the small number of victims were focused upon, there were more maximal deviations and higher X_flips in the individualism priming group than in the collectivism priming group, which showed that the participants in the individualism condition had more deliberative processes before choosing their answers between utilitarianism and deontology. In addition, the participants in the individualism priming condition showed more maximal deviations in the mouse trajectories regarding ingroup related interventions in moral dilemmas than those in the collectivism priming condition. These results implicated the possibilities that the automatic emotional process and the controlled deliberative process in moral decision making might interact with cultural dispositions of the individuals and the focus of situations.

• Korean Journal of Culture and Social Issue
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• v.29 no.1
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• pp.53-74
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• 2023

The purpose of this study was to identify the priming effects of disaster-related news. Specifically, this study aimed to examine the priming effects about trauma words and neutral words according to the geographical and psychological distance from the disaster. The participants in this study were 75 college students who had not experienced the Daegu subway fire accident, and whom were not ruled out after completing the screening measure completing the screening measure the completion of questionnaires for screening. All participants conducted a lexical decision task after watching a news video about the Daegu subway fire accident. The design was a 2 (Geographical distance: close vs. distant) × 2 (Psychological distance: close vs. distant) × 2 (Priming type: trauma priming vs. neutral priming) mixed-design. The results of this study are summarized as follows: First, the group which was geographically closer to the disaster tended to revealed a largerbigger priming effect than the distant group-a trend toward significance. Second, within the psychologically closer to the disaster, group, for those who were geographically closer too, the priming effect was larger for those who were geographically closer geographically closer than for the geographically distant group. Third, the geographically closer group had a largerbigger neutral priming effect than the distant group. Fourth, the psychologically distant group had a largerbigger neutral priming effect than the close group. To sum up, this study identified that disaster news coverage may have an implicit effect on people, and this influence can change according to the geographical and psychological distance. Finally, this study discussed the limitations of the study and recommendations for further research.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.217-220
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• 2010

This paper presents an achieving method of reducing maximum acceleration for the missile by decrease of burst pressure in a nozzle closure. The relation of notch shape and burst pressure for a nozzle closure is examined by experiment. In the point of maximum acceleration reduction for a missile, an improved nozzle closure effects well compared with that of a reference closure by ground burning test of a gas generator.

• Korean Journal of Cognitive Science
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• v.23 no.1
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• pp.1-23
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• 2012

This study investigated the lexical access processing of inflected Korean verbs in the mental lexicon. In Korean, verbs can be classified into two main types of inflections, which are regular and irregular inflections, which can be further divided into three types of regular inflections and two types of irregular inflections. A masked priming lexical decision task was used and the priming effects were compared. Experiments were carried out using the five different types of verbal inflections in Korean: (1) No change-regularity (regular verbs with no orthographical or phonological changes), (2) Phonological change-regularity (regular verbs with phonological changes to the stem only), (3) Orthographical change-regularity (regular verbs that only undergo orthographical changes), (4) Stem change-irregularity (the stem is omitted or alternated with the other phoneme of the stem in irregular verbs), (5) Ending change-irregularity (irregular verbs with changes in the endings by phoneme substitution). The first three types are regarded as regular verbal inflections whereas the latter two types are regarded as irregular verbal inflections. The infinitive forms of the verb were presented as target words and three different conditions were presented as prime words. The three conditions included regular verbal inflection, irregular verbal inflection, and a control condition in which morphologically and semantically unrelated primes were presented. In addition, different stimulus onset asynchrony (SOA) were manipulated (43ms, 72ms, 230ms) to examine the time frame of the morphological decomposition process in word recognition. The results revealed that there were significant priming effects in all three SOAs across conditions. Hence, there was no significant differences in priming effects between regular and irregular verbal inflection conditions. This may suggest that Korean verb processing does not adopt different processing routes for regular and irregular inflections, which can also be an indication of earlier morphological information processing for Korean verbs.

• Journal of the Korean Institute of Gas
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• v.20 no.3
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• pp.30-37
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• 2016

Electrical apparatuses for use in the presence of flammable gas atmospheres have to be specially designed to prevent them from igniting the explosive gas. Flameproof design implies that electrical components producing electrical sparks are contained in enclosures and withstand the maximum pressure of internal gas or vapours. In addition, any gaps in the enclosure wall have to designed in such a way that they will not transmit a gas explosion inside the enclosure to an explosive gas or vapours atmosphere outside it. In this study, we explained some of the most important physical mechanism of MESG(Maximum Experimental Safe Gap) that the jet of combustion products ejected through the flame gap to the external surroundings do not have an energy and temperature large enough to initiate an ignition of external gas or vapours. We measured the MESG and maximum explosion pressure of ternary gas mixtures(propane-acetylene-air) by the test method and procedure of IEC 60079-20-1:2010. As a result, the composition of propane gas that has lower explosive power than acetylene gas in the ternary gas mixtures makes greater effects on MESG and explosion pressure.