• 제목/요약/키워드: Phase Consistency

검색결과 157건 처리시간 0.025초

Emulsion stability of cosmetic creams based on water-in-oil high internal phase emulsions

  • Park, Chan-Ik;Cho, Wan-Gu;Lee, Seong-Jae
    • Korea-Australia Rheology Journal
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    • 제15권3호
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    • pp.125-130
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    • 2003
  • The emulsion stability of cosmetic creams based on the water-in-oil (W/O) high internal phase emulsions (HIPEs) containing water, squalane oil and cetyl dimethicone copolyol was investigated with various compositional changes, such as electrolyte concentration, oil polarity and water phase volume fraction. The rheological consistency was mainly destroyed by the coalescence of the deformed water droplets. The slope change of complex modulus versus water phase volume fraction monitored in the linear viscoelastic region could be explained with the resistance to coalescence of the deformed interfacial film of water droplets in concentrated W/O emulsions: the greater the increase of complex modulus was, the more the coalescence occurred and the less consistent the emulsions were. Emulsion stability was dependent on the addition of electrolyte to the water phase. Increasing the electrolyte concentration increased the refractive index of the water phase, and thus decreased the refractive index difference between oil and water phases. This decreased the attractive force between water droplets, which resulted in reducing the coalescence of droplets and increasing the stability of emulsions. Increasing the oil polarity tended to increase emulsion consistency, but did not show clear difference in cream hardness among the emulsions.

달의 위상 변화 설명에 대한 예비 중등 교사의 설명적 일관성 (An Explanatory Consistency of Preservice Secondary Teachers' Explanations about the Lunar Phases)

  • 오준영
    • 한국지구과학회지
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    • 제27권6호
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    • pp.606-619
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    • 2006
  • 본 연구에서는 예비 중등 교사들이 가지고 있는 달의 위상 변화에 대한 설명적 일관성을 탐색하기 위해서 설명적 일관성의 조건을 제안하고 그 일관성에 따른 유형들을 탐색하였다. 본 연구에서는 천문현상에 대한 정신 모형을 설명적 일관성의 관점에서 다음의 4가지 유형으로 분류하였다. 첫째, ad hoc의 확장형, 둘째, 경쟁 이론의 단순한 추가형, 셋째, 처음 이론에 강한 의문을 가지지만 처음 이론과 경쟁 이론 간의 설명 불가능한 과도기 모형, 넷째, 상황에 따라서 처음 이론과 과학적 이론인 경쟁 이론을 상황에 따라서 사용하고 있는 과도기 모형이다.

RHEOLOGICAL CONSISTENCY OF CONCENTRATED WATER-IN-OIL EMULSION

  • Park, C-I.;Yang, J-C.;Cho, W-G.;S-H. Kang
    • 대한화장품학회지
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    • 제24권3호
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    • pp.129-133
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    • 1998
  • We have studied a relationship between the pattern of complex modulus change versus internal phase volume ratio and the rheological consistency of concentrated W/O emulsions with Magnesium Sulfate in the range 0.0 to 0.5 wt% and with different oil polarities, respectively. The rheological consistency with time of concentrated W/O emulsion was checked using Fudoh Rheometer and the coalescence of deformed water droplets was examined using polarized light microscope(LEICA DMRP). To find the pattern of complex modulus change of the concentrated emulsions versus internal phase volume ratio, the effect of varying water phase volume fraction from 0.78 up to 0.85 on viscoelastic measurements was investigated using rotational rheometer (HAAKE Rheostress RS 50). The rheological consistency was mainly destroyed by the coalescence of the deformed water droplets. The greater the increase of complex modulus was, the less coalescence occurred and the more consistent the concentrated emulsions were. And the pattern of complex modulus increase versus volume ratio has been explained with the resistance to coalescence of the deformed interfacial film of water droplets in concentrated W/O emulsion.

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실시설계단계 BIM과 도면의 정합성 검토를 위한 체크리스트 개발 (A development of a checklist to check the consistency of BIM and drawings at the construction documentation phase)

  • 김병주;김이제;진상윤
    • 한국BIM학회 논문집
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    • 제8권1호
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    • pp.33-42
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    • 2018
  • The consistency between a building information model(BIM) and drawings are very important and has a critical impact on the usage of BIM throughout the project life-cycle. The purpose of this study is to develop a checklist for the consistency check between BIM and drawings. In this research, requirements for drawings in the construction documentation phase were analyzed. In generating drawings based on BIM, a checklist can help practitioners confirm what to modify in the BIM model and what to modify in CAD drawings. Finally, it is expected that the work efficiency will be improved by reducing the unnecessary work by distinguishing the elements that can be extracted from the BIM model from the elements that requires additional works when generating BIM-based drawings.

Stability of High Internal Phase Emulsions

  • Park, C.I.;Cho, W.G.
    • 대한화장품학회지
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    • 제25권4호
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    • pp.65-74
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    • 1999
  • We have studied the stability of W/O high internal phase emulsions(HIPE) containing water, cetyl dimethicone copolyol and oils varying magnesium sulfate in the range 0 to 0.5 wt% and oil polarities, respectively. The rheological consistency was mainly destroyed by the coalescence of the deformed water droplets. The greater the increase of complex modulus was, the less coalescence occurred and the more consistent the concentrated emulsions were. The increasing pattern of complex modulus versus volume fraction has been explained with the resistance to coalescence of the deformed interfacial film of water droplets in concentrated W/O emulsion. The stability is dependent on: (i) the choice of the oil is important, the requirements coincide with the requirements for the formation of the rigid liquid crystalline phases; and (ii) addition of salts the aqueous phase opposes the instability due to coalescence. Increasing the salt concentration increases the refractive index of the aqueous phase. It lowers the difference in the refractive index between the oil and aqueous phases. This decreases the attraction between the water domains, thus increasing the stability.

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Stability of High Internal Phase Emulsions

  • Park, C-I.;W-G. Cho
    • 대한화장품학회:학술대회논문집
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    • 대한화장품학회 1999년도 IFSCC . ASCS 학술대회 발표 논문
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    • pp.65-74
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    • 1999
  • We have studied the stability of W/O high internal phase emulsions(HIPE) containing water, cetyl dimethicone copolyol and oils varying magnesium sulfate in the range 0 to 0.5wt% and oil polarities, respectively. The rheological consistency was mainly destroyed by the coalescence of the deformed water droplets. The greater the increase of concentrated modulus was, the less coalescence occurred and the more consistent the concentrated emulsions were. The increasing pattern of complex modulus versus volume fraction has been explained with the resistance to coalescence of the deformed interfacial film of water droplets in concentrated W/O emulsion. The stability is dependent on: (i) the choice of the oil is important, the requirements coincide with the requirements for the formation of the rigid liquid crystalline phases :5; and (ii) addition of salts the aqueous phase opposes the instability due to coalescence:. Increasing the salt concentration increases the refractive index of the aqueous phase. It lowers the difference in the refractive index between the oil and aqueous phases. This decreases the attraction between the water domains, thus increasing the stability.

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왁스류(類)가 유중빙형(油中氷型)크림의 조도(稠度)에 미치는 영향 (Influence of Various Waxes on Consistency of W/O Type Cream)

  • 배봉진;최영욱;김종갑
    • Journal of Pharmaceutical Investigation
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    • 제15권3호
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    • pp.121-129
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    • 1985
  • Influences of various waxes on the consistency of cream was investigated by inspections through microscope, rheometer and sensory test. Fatty acids, higher fatty alcohols, hydrocarbons, and some of natural waxes were used in this experiment. Most above waxes showed good state of emulsion at low concentration, but at higher concentration $(7.0{\sim}8.0%)$, they showed not only an unstable emulsion state but also a critical point of content in consistency. At this critical point of content, the consistency of w/o type cream was increased irregularly. So, it could be identified that consistency of a w/o type cream was strongly dependent on kinds and contents of waxes in continuous phase.

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카오스 이론을 이용한 2상 유동 해석 (A Review on Two-Phase Flow Analysis using Chaos Theory)

  • 권정태;권영철;김경민
    • 전기학회논문지P
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    • 제56권1호
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    • pp.23-27
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    • 2007
  • This article presents a review on chaos analysis of two-phase flow. Chaos theory has recently been applied to two-phase flow analysis, and it gives promising measures to quantitatively identify two-phase flow patterns and pool boiling behaviors. But, consistency of the calculated chaotic measures were not completely confirmed yet. More experimental data are requested for chaos analysis of two-phase flow. Also, chaos analysis methodology should be developed by experimental verification.

치과용 합금 주조 시 주조링의 계류시간에 따른 보철물의 변연 적합도 실험에 관한 연구 (An Experimental Study on Margin Consistency of Prosthesis According to the Continued Time of Casting-Ring in the course of the Casting of Dental Alloy)

  • 황성식;이상혁
    • 대한치과기공학회지
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    • 제23권2호
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    • pp.179-188
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    • 2002
  • With regard to the manufacture of dental prosthesis, all the dental mechanism is of vital significance at the aspect of activating its function by fixing the prosthesis to Patient's oral cavity. However, if there we will take our immediate action without the discretion about its process none the less for the importance of dental mechanism, then we might have a serious problem. Accordingly, there need to pay attention to the dilatability makes up for the shrinkage state occurring by the feature of metal materials and manufacturing process which appeared in the process of dental mechanism, which eventually is expected to playa very important role in casting a dental prosthesis appropriate to one's oral tissue. This study was designed to take into account of the effects on margin consistency of prosthesis according to the continued time of casting-ring in the course of the casting of dental alloy. For this, the researcher made an experiment on the casting of dental alloy, its dilatability, and the change of phase. The results of this study were as follows: First, the researcher could see that the sample which was cast under the condition of $650^{\circ}C/20$ Minutes(the continued time) was far superior to others at the aspect of margin consistency. Second, according to the measurement of expansion coefficient by Dilatometer, the researcher perceived the fact that the expansion-coefficient showed a maximum of $37.1{\mu}m$ considering the sample's length which was cast with ordinary temperature under the condition of $650^{\circ}C/20$ Minutes. Third, from the result of X-ray diffraction under the condition of $650^{\circ}C/20$ Minutes(the continued time), the researcher could find that there's no difference between the change of phase and its intensity. As mentioned above, the researcher could ascertain the fact that its contraction don't give rise to the change of phase.

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Cross-cultural Validation of Instruments Measuring Health Beliefs about Colorectal Cancer Screening among Korean Americans

  • Lee, Shin-Young;Lee, Eunice E.
    • 대한간호학회지
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    • 제45권1호
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    • pp.129-138
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    • 2015
  • Purpose: The purpose of this study was to report the instrument modification and validation processes to make existing health belief model scales culturally appropriate for Korean Americans (KAs) regarding colorectal cancer (CRC) screening utilization. Methods: Instrument translation, individual interviews using cognitive interviewing, and expert reviews were conducted during the instrument modification phase, and a pilot test and a cross-sectional survey were conducted during the instrument validation phase. Data analyses of the cross-sectional survey included internal consistency and construct validity using exploratory and confirmatory factor analysis. Results: The main issues identified during the instrument modification phase were (a) cultural and linguistic translation issues and (b) newly developed items reflecting Korean cultural barriers. Cross-sectional survey analyses during the instrument validation phase revealed that all scales demonstrate good internal consistency reliability (Cronbach's alpha=.72~.88). Exploratory factor analysis showed that susceptibility and severity loaded on the same factor, which may indicate a threat variable. Items with low factor loadings in the confirmatory factor analysis may relate to (a) lack of knowledge about fecal occult blood testing and (b) multiple dimensions of the subscales. Conclusion: Methodological, sequential processes of instrument modification and validation, including translation, individual interviews, expert reviews, pilot testing and a cross-sectional survey, were provided in this study. The findings indicate that existing instruments need to be examined for CRC screening research involving KAs.