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Demulsification of Oil-Water Emulsions Using Different Microwave Irradiation Mode (마이크로파 조사 방식에 의한 Oil-Water 에멀젼 분리)

  • Hong, Joo-Hee;Kim, Byoung-Sik;Kim, Dok-Chan
    • Applied Chemistry for Engineering
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    • v.16 no.5
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    • pp.653-659
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    • 2005
  • When emulsion is irradiated by a microwave, the energy absorbed by the emulsion is proportional to irradiation time. In case of a long exposure, the temperature of emulsion rises, its viscosity decrease, and subsequently increase the rate of demulsification. In this work, in order to improve demulsification rate, the studies on demusification and the Sauter mean diameter ($D_{32}$) for each microwaved emulsion with different irradiation mode(continuous, pulsative, and periodical irradiation) have been carried out. When the 30% W/O emulsion (sample #1) was irradiated for 600 sec and settled for 24 h, oil recovery rates from continuous, pulsative, and periodical microwave irradiation were 60.0%, 62.3%, and 96.2%, and the amounts of separated water were 26.5%, 35.0%, and 93.9%, respectively. Also, the Sauter mean diameters ($D_{32}$) were $47.183{\mu}m$, $111.547{\mu}m$, and $220.476{\mu}m$, respectively.

Cure Kinetics, Thermal Stabilities and Rheological Properties of Epoxy/phenol Resin Blend System Initiated by Cationic Thermal Latent Catalyst (양이온 열잠재성 개시제에 의한 에폭시/페놀 수지 브랜드 시스템의 경화 동력학.열안정성 및 유변학적 특성)

  • 박수진;서민강;이재락
    • The Korean Journal of Rheology
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    • v.11 no.2
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    • pp.135-142
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    • 1999
  • The effects of 1 wt.% N-benzylpyrazinium hexafluoroantimonate (BPH) as a thermal latent initiator and blend compositions composed of 0, 5, 10, 20 and 40 wt.% of phenol-novolac resin to epoxy resin were investigated in terms of cure kinetics, thermal stabilities and rheological properties. Thermal latent properties of BPH were measured from the conversion as a function of reaction temperature on a dynamic DSC. This cationic BPH system turned out to be an effective thermal latent initiator in the epoxy-phenol curing system. And the increase of phenol-novolac resin concentration led to the decrease in the latent temperature and to the increase of cure activation energy ($E_a$) of the blend system. The thermal stability and activation energy ($E_t$) for decomposition, gel-time and activation energy ($E_c$) for cross-linking from rheometer increased within the composition range of 20~40 wt.% of phenol-novolac resin. This implies that the three-dimensional cross-linking may take place among hydroxyl group within phenol resin, epoxide ring within epoxy resin and BPH.

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Thermotropic Liquid Crystalline Properties of Cholesteryloxycarbonated and (Cholesteryloxycarbonyl) alkanoated Celluloses (콜레스테릴옥시카본화 그리고 (콜레스테릴옥시카보닐)알카노화 셀룰로오스들의 열방성 액정 특성)

  • Jeong, Seung-Yong;Ma, Yung-Dae
    • Polymer(Korea)
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    • v.32 no.2
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    • pp.169-177
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    • 2008
  • The thermal and optical properties of cellulose tri(cholesteryloxy) carbonate(CCE0) and cellulose tri(cholesteryloxycarbonyl)alkanoates (CCEn, n=$2{\sim}8$, 10, the number of methylene units in the spacer) were investigated. CCE0 formed an enantiotropic cholesteric phase, whereas all the CCEn exhibited monotropic cholesteric phases. CCEn with n=$3{\sim}8$ formed cholesteric phases with left-handed helical structures whose optical pitches (${\lambda}_m's$) decrease with increasing temperature. On the other hand, CCE0 and CCEn with n=2 or 10 did not display reflection colors over the full cholesteric range, suggesting that the helical twisting power of the cholesteryl group highly depends on the length of the spacer connecting the cholesteryl group to the main chain. The thermal stability and degree of order in the mesophase and the temperature dependence of the ${\lambda}_m$ observed for CCEn highly depended on n. The results were discussed in terms of the differences in the internal plasticization, the arrangement of the side groups, and the conformation of the molecules.

Urban Ecotourism Site Visitors' Satisfaction and Behavioral Intentions to Revisit - A Case Study of the Sincheon Ecotourism Site in Daegu (도심 생태관광지 방문객의 만족과 행동의도 -대구시 신천을 중심으로-)

  • Roh, Yong-Ho;Kim, Byeong-Yong;Kim, Hak-Yoon
    • Journal of the Korean association of regional geographers
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    • v.16 no.3
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    • pp.315-323
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    • 2010
  • The purpose of this study was to investigate the relationship between the determinant factors of visitors' satisfaction and behavioral intentions to the Shincheon stream in Daegu city. It was found that ecology of the Shincheon stream, signals about ecology, and physical facilities positively influenced overall satisfaction. Physical facilities more positively influenced overall satisfaction. The overall satisfaction positively influenced behavioral intentions. For the future studies, it is necessary to do research visitors' satisfaction with more diverse factors of satisfaction and longitudinal studies about visitors' satisfaction based on seasonally different visitors.

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The Analysis on the Sensitive Hand Characteristics and Appearance Performance of Thobe Fabric for Man in the Middle-East Region (중동지역 남성복 Thobe 직물의 감성 태 특성 분석과 외관성능 분석)

  • Kim, Seung-Jin
    • Science of Emotion and Sensibility
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    • v.11 no.4
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    • pp.449-460
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    • 2008
  • PET fabric is used as a regular clothing in the middle-east region which is called Chador as a women's clothing and Thobe as a men's clothing. Then there is a big difference of export price according to the minute hand characteristics of the PET fabrics, of which characteristics are due to the fibre and manufacturing process characteristics. This research surveys the optimum manufacturing conditions related to the fibre and fabric for the Thobe clothing which were developed in this study through comparison with high price Teijin Thobe manufactured in Japan. In this research, four kinds of Teijin fabrics made in Japan were prepared as a target quality specimen, and five kinds of developed fabrics were produced as an experimental specimens. These specimens were made by changing yarn denier, twist, yarn setting conditions and fabric density, which are also changed by twist contraction, weaving and finishing shrinkages. As a result of this study, the sensitive characteristics of Teijin Thobe fabrics can be analysed from fibre and fabric, and then the manufacturing design technology was constructed under the base of low twist texturing and 3 dimensional fabric design simulation technologies.

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An Empirical Study on the Network Theory, Economic Structure and Economic Shocks: The Implications on Technology Economics (네트워크이론과 경제구조 그리고 경제충격에 관한 실증연구: 기술경제적 함의)

  • Cho, Sang Sup;Kang, Shin-Won
    • Journal of Korea Technology Innovation Society
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    • v.16 no.4
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    • pp.937-953
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    • 2013
  • The theoretical discussion of generation process and development directions of economic fluctuations are actively discussed. This study describes the economic changes applied to empirical research on economic volatility in Korea under the economic theory of network theory [Acemoglu, et al. 2012, 2010]. For the three years in 2000, 2005, and 2010, the network analysis were applied to industry input-output tables. The research results show that the network economic structures in Korea is shifted from a high connectivity among sectors to a lower connectivity. Also, the impact of key industries and the mutual connectivity of input and out among industrial sectors are weaken. Implications for industry and technology policy are derived form the study results.

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The Effects of Self-Efficacy and User's Cognitive Factors on Reuse Intention of SNS (SNS에 대한 자기효능감과 사용자 인지요인이 SNS 재사용 의도에 미치는 영향)

  • Lee, Hong-Jae;Choi, Moon-Hyeong;Park, Mi-Kyung
    • Journal of the Korean Society for information Management
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    • v.29 no.3
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    • pp.145-167
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    • 2012
  • The purpose of this study is to examine the causal relationships among self-efficacy, perceived usefulness, perceived ease of use, perceived playfulness, and reuse intention of SNS. The results of data analysis by structured equation model(SEM) indicate that self-efficacy significantly influences individual's perceived ease of use, perceived usefulness and perceived playfulness. Both perceived playfulness and perceived ease of use affects perceived usefulness on SNS. Individual's self-efficacy, perceived playfulness and perceived usefulness affect reuse intention of SNS. Based on the results, the theoretical and practical implications of this study are discussed.

Effect of Self Characteristics and Contents Characteristics in Consumers' Empathic Response (콘텐츠 특성과 자아특성이 소비자 공감반응에 미치는 영향)

  • Yun, Dae-Hong
    • Management & Information Systems Review
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    • v.34 no.4
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    • pp.97-120
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    • 2015
  • This study examined the role and relationship among cognitive response(attractiveness, familiarity, actual self-congruence, ideal self-congruence and sympathy) factors, emotional response(empathy, flow, affection) factors, identification mediating between cognitive and emotional response, and interactivity. Hypotheses based on literature reviews were analyzed and according to the results, all of hypotheses except two hypotheses were supported. Firstly, the results revealed that except characteristic attractiveness and actual self-congruence, story attractiveness, characteristic familiarity, story familiarity, and ideal self-congruence influenced on sympathy positively. Secondly, this study examined the role and relationship between identification mediating between cognitive and emotional response and interactivity. As a result, identification and interactivity mediated with sympathy and empathy had positive effects. Finally, in respect of emotional responses empathy, flow, and affection had positive effects.

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