• 제목/요약/키워드: cmc

검색결과 925건 처리시간 0.025초

Salt Effects on the Critical Micelle Concentration and Counterion Binding of Cetylpyridinium Bromide Micelles

  • Jong Jae Chung;Sang Wook Lee;Joon Ho Choi
    • Bulletin of the Korean Chemical Society
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    • 제12권4호
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    • pp.411-413
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    • 1991
  • The effects of electrolyte on the critical micelle concentration (cmc) and bromide counterion binding in the micelles of cetylpyridinium bromide (CPB) have been investigated by UV spectroscopy and conductance measurements. Salts used in this study decreased cmc in the order $Cl^-\;<\;Br^-\;<\;NO3^-$ (which parallels the lyotropic series for the inorganic anions) and the effects on cmc followed the equation proposed by Shinoda: log cmc = A - B log (cmc + [NaX]). In the equation, constant B represents the counterion binding to the micelles at cmc and for the micelle of CPB at $25^{\circ}C$, B=80.76%. The association constant for the binding of counterions to long chain cations within micelles was also derived from the cmc values and counterion binding constant to the micelles.

Eulerian 및 Lagrangian CMC 모델을 사용한 디젤분무연소 모델링에 관한 연구 (A Study on Diesel Spray Combustion Modeling by Eulerian and Lagrangian Conditional Moment Closure Models)

  • 김우태;조현수;허강열
    • 한국연소학회:학술대회논문집
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    • 한국연소학회 2012년도 제45회 KOSCO SYMPOSIUM 초록집
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    • pp.195-198
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    • 2012
  • Numerical simulation is performed to evaluate the conditional moment closure (CMC) models for spray development, ignition, and turbulent combustion for the Engine Combustion Network (ECN) test cases. The CMC model is implemented in the open source code, OpenFOAM, to provide conditional flame structures through the solution of Eulerian as well as Lagrangian conditional transport equations. In spite of more accurate treatment of the convective term, Eulerian CMC provides similar ignition delays and lift-off lengths with Lagrangian CMC.

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CMC SURFACES FOLIATED BY ELLIPSES IN EUCLIDEAN SPACE E3

  • Ali, Ahmad Tawfik
    • 호남수학학술지
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    • 제40권4호
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    • pp.701-718
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    • 2018
  • In this paper, we will study the constant mean curvature (CMC) surfaces foliated by ellipses in three dimensional Euclidean space $E^3$. We prove that: (1): Surfaces foliated by ellipses are CMC surfaces if and only if it is a part of generalized cylinder. (2): All surfaces foliated by ellipses are not minimal surfaces. (3): CMC surfaces foliated by ellipses are developable surfaces. (4): CMC surfaces foliated by ellipses are translation surfaces generated by a straight line and plane curve.

Rat에서 carboxymethyl chitosan의 복강수술후 유착형성에 미치는 효과 (Effect of carboxymethyl chitosan on postoperative intraperitoneal adhesion formation in the rat)

  • 장광호;권영삼;김정은;권은주;오태호;이근우;장인호
    • 대한수의학회지
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    • 제40권3호
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    • pp.635-643
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    • 2000
  • 본 실험은 carboxymethyl chitosan(CMC)이 복강유착에 미치는 효과를 밝히고자 수행하였다. 총 44마리의 rat를 유착유도후 아무런 처치하지 않은 대조군과 각각 1, 2, 3% CMC 용액 3ml로 처치한 3개 실험군 등 총 4군으로 나누었다. 유착은 회장의 장간막 반대측 장막부위를 노출시켜 수술도로 $0.5{\times}1cm$ 크기로 긁어 점상출혈을 유도하고, 우측벽측복막을 $0.5{\times}1cm$ 간격으로 창상을 유도한 후 두 창상을 봉합하였다. 2주후 halothane에 의한 안락사 후 유착정도를 computerized tensiometer로 측정하였다. 유착부 분리에 필요한 장력(Newton)은 대조군이 평균 $2.48{\pm}0.88$이었으며, 1% CMC 처치군은 $1.86{\pm}0.56$, 2% CMC 처치군은 $1.75{\pm}0.71$, 3% CMC 처치군은 평균 $1.55{\pm}0.60$로 3% CMC 처치군에서 유의적인 감소(p<0.01)가 나타났다. 이상의 결과로 미루어 rat에서 복강수술후 CMC의 복강내 투여는 복강장기 유착방지에 효과적이라고 사료된다.

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CMC기반의 영어학습 환경에서 상호작용 촉진을 위한 교수설계가 영어학습에 미치는 효과 : 교양 영작문 과목을 중심으로 (A Study on the Effectiveness of the Instructional Design for Further Interaction on English Learning in a CMC Based Language Learning Environment: Focusing on University General English Education)

  • 정양수
    • 한국영어학회지:영어학
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    • 제3권2호
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    • pp.281-308
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    • 2003
  • The purpose of this study is to determine the effects of CMC-based English learning. In this study, CMC components were found to provide circumstances of facilitating interactions between student-student and student-student-teacher, which enabled students to accomplish language learning tasks. Findings of this study are as follows: First, CMC based language learning experience helps students have positive attitudes toward their English language learning. Second, student-student-instructor interaction group outperformed other groups in academic achievement and class activity participation. Third, cooperative learning groups more actively participated in the class activity than the individual learning group resulting in better academic performances. These findings supported the fact that cooperative learning with CMC components are useful in bringing more class participation and positive attitude that were believed to foster language learning than other groups in traditional language learning environments. This study suggests that the instructor needs to use instructional design strategies helpful to facilitate active interactions between instructors and students in order to achieve better effectiveness of English learning in a CMC based learning environment.

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임계 마이셀 농도의 온도 의존성에 대한 통계 역학적 모델 (A Statistical-Mechanical Model on the Temperature Dependence of Critical Micelle Concentration)

  • 임경희;강계홍;이미진
    • 공업화학
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    • 제17권6호
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    • pp.625-632
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    • 2006
  • 임계 마이셀 농도의 온도 의존성을 통계 역학적으로 고찰하였다. 본 논문에서 논의된 단순하고 소박한 모델은 임계 마이셀 농도(CMC)가 온도에 대해서 ln CMC= A+BT+C/T+D ln T와 같이 변함을 말해준다. 여기에서 T는 온도이고 A, B, C, D는 마이셀을 이루는 계면활성제 분자의 성질에 의존하는 상수이다. 모델에서 얻어진 식은, 온도에 따른 CMC 측정 자료를 잘 맞춤하는 것으로 평가된, 기존의 Muller와 Lim의 식을 결합한 형태이다. 그러므로 본 논문에서 제안된 CMC의 온도 의존성에 대한 모델은 Muller와 Lim의 식에 대한 이론적인 토대를 제공한다.

반응표면분석법을 이용한 실리카복합재료의 레올로지 속성 개선 (Improvement of Rheological Properties of Silica Composites Employing Response Surface Methodology)

  • 임기홍;양승남;김남기
    • 폴리머
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    • 제32권1호
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    • pp.19-25
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    • 2008
  • 본 논문은 실리카복합재료인 치약제의 결합제 역할을 하는 수용성 폴리머인 carboxymethylcellulose (CMC)와 carbomer, Mg/Al silicate의 최적의 조성 비율을 구하여 치약제의 레올로지 속성을 개선하는 데에 목적이 있다. 실험계획법 중 혼합물 반응표면분석법을 적용하여 응력, 겔 강도, 늘어짐, 탄성에 대해 oscillatory 레오미터로 측정하였다. 실험 결과 CMC와 carbomer는 치약제의 겔 강도와 응력에 많은 영향을 미치고, CMC는 치약제의 늘어짐을 초래하며, CMC와 Mg/Al silicate가 탄성에 도움이 된다는 사실을 규명하였다. 반응치 최적화를 통해 최적의 폴리머 및 silicate 조성비를 구하여 실험한 결과 개선된 레올로지 속성의 치약제를 확인할 수 있었다.

Carboxymethyl Chitosan Promotes Migration and Inhibits Lipopolysaccharide-Induced Inflammatory Response in Canine Bone Marrow-Derived Mesenchymal Stem Cells

  • Ryu, Ho-Sung;Ryou, Seong-Hwan;Jang, Min;Ku, Sae-Kwang;Kwon, Young-Sam;Seo, Min-Soo
    • 한국임상수의학회지
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    • 제38권6호
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    • pp.261-268
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    • 2021
  • The study was conducted to evaluate the effects of carboxymethyl chitosan (CMC) on proliferation, migration, and lipopolysaccharide (LPS)-induced inflammatory response in canine bone marrow-derived mesenchymal stem cells (BMSCs). The proliferation and migration of BMSCs were examined after treatment with CMC. The effect of CMC on the mRNA expression of inflammatory cytokines, such as interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α, IL-10, and transforming growth factor (TGF)-β, was also evaluated by reverse transcription polymerase chain reaction (RT-PCR). In the proliferation assay, no significant changes were found at all CMC concentrations compared with controls. The migration assay showed that CMC dose-dependently stimulated the migration of BMSCs in normal and LPS-treated conditions. RT-PCR showed that TNF-α and IL-10 expressions were suppressed in the BMSCs after CMC treatment. However, other genes were not affected. Taken together, CMC promoted BMSC migration and inhibited TNF-α and IL-10. Therefore, CMC may be possible to regulate wound healing when mesenchymal stem cells are applied in inflammatory diseases.

급식 대상 유형과 위탁급식전문업체 규모별 고객 만족도에 영향을 미치는 서비스 품질 속성의 규명 (Identifying the Effect of Service Quality Attributes on an Overall Customer Satisfaction by the Foodservice Type and the Contract Management Company(CMC) Scale)

  • 박문경
    • 대한영양사협회학술지
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    • 제13권2호
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    • pp.138-156
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    • 2007
  • The purposes of this study were to a) measure the service quality attributes of foodservice type such as school foodservice, hospital foodservice and business & industry(B&I) foodservice, managed by contract management company(CMC), b) compare with service quality attributes by CMC scale, c) analyze overall customer satisfaction(CS) by the foodservice type and the CMC scale, and d) identify the effect of service quality attributes on an overall CS by the foodservice type and the CMC scale. The questionnaires were handed out to 6,620 customers of 207 school, 38 hospital, and 86 B&I foodservices in 108 CMCs. The statistical data analysis was completed using SPSS Win(ver 12.0) for descriptive analysis, t-test, reliability analysis, and multiple linear regression analysis. From an analysis on service quality attributes, 'proper arrangement of table and chair at hall distribution(3.53)', 'operation of nutrition education(3.50)' were highly perceived to student, 'correctable serving(4.08)', 'serve at fixed distribution time(4.08)', 'kindness of serving employee(4.04)' were highly perceived to patient, 'employee's kindness(3.84)' were highly perceived to customer of B&I. In comparison of service quality attributes by CMC scale, most scores of large enterprise(LE) were significantly higher than small and medium sized enterprise(SME) in school foodservice, hospital foodservice and B&I foodservice. Overall CS levels were 3.53 out of a maximum 5 on B&I, 3.46 on school, and 3.44 on hospital and were evaluated differently CS score by CMC scale. Finally, regression results for the effects of service quality attributes on overall CS by each of foodservice type were identified significantly different service quality attributes by foodservice type such as school, hospital, B&I(p<.001) and by CMC scale. For considering the goal of enterprise on profit-making through CS and the needs of customer on CS at moment of truth(MOT), the findings should be applied to the CMC and the foodservice industry.

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교정 및 측정능력(CMC)이 한국의 무역에 미치는 영향에 관한 실증분석 (A Empirical Study about the Impact of the Calibration and Measurement Capability(CMC) on Korean Trade)

  • 박주근;한성;박종선
    • 기술혁신연구
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    • 제25권2호
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    • pp.127-152
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    • 2017
  • 1995년 WTO 체제가 출범한 이후 전통적인 무역장벽 이외에 기술규정, 표준 및 적합성평가절차 등과 같은 비관세 기술장벽이 국가 간 교역의 중요한 이슈로 대두되었다. 본 연구는 무역기술장벽의 제거에 필요한 기술기반을 마련하기 위하여 국가측정표준기관(NMIs) 간에 체결된 국제도량형위원회 상호인정협정(CIPM MRA)의 이행이 한국의 교역에 어떠한 영향을 미치는지에 대하여 분석하였다. 국가측정표준의 동등성에 관한 자료인 CMC를 대용변수(proxy)로 중력모형을 활용하여 실증분석한 결과, CMC는 한국의 교역에 긍정적인 영향을 미치는 것으로 나타났다. 특히, 소득이 높은 국가의 CMC가 낮은 국가에 비하여 더 큰 영향을 주는 것으로 나타났다. 이러한 결과는 우리나라와 같이 무역의존도가 높은 국가의 경우, 공공재로 인식되고 있는 국가측정표준의 확립과 향상을 위하여 지속적인 자원투입을 하는 것이 경제성장에 중요한 역할을 할 수 있다는 점을 시사한다.