Molecular Area and Interfacial Tension Behavior of High Efficiency Cosurfactants

김천희,Kim, Chunhee Korean Chemical Society 1996 대한화학회지 Vol.40 No.1

Gibbs' adsorption isotherms을 이용하여, 계면에서 보조계면활성제 분자의 분자 면적과 계면장력거동에 미치는 ethylene oxide(EO)와 propylene oxide(PO)의 영향을 조사하였다. 일반식 $C_4H_9O(EO)m(PO)_nH$를 갖는 alcohol들의 보조계면활성제로서의 특성을 연구하였는데, 이 alcohol들은 일반적으로 사용되는 보조계면활성제에 비해서 분자량이 크며 계면활성 또한 큰 특성을 갖고있다. EO와PO의 몰수와 이들이 첨가된 상대적 순서는 물/기름 계면에서 alcohol 분자의 분자면적과 계면장력 특성에 큰 영향을 미치는 것을 알 수 있었으며, 다음의 결론을 얻었다. 1) PO는 EO에 비해서 계면흡착 효율은 낮으나, 계면장력 저하 능력은 더 크다. 2) 분자량은 같으나 구조가 다른 분자들, 즉 EO와PO의 첨가 순서만 다른 분자들의 경우는, 계면흡착 효율이 큰 (계면에서의 분자면적이 작은) 분자들이 계면장력 저하 능력이 더 크다. 3) 동일한 친유기에 EO나 PO가 많이 첨가될수록, 분자들의 계면에서의 분자면적은 커지나 계면장력 저하능력도 커진다. Gibbs' adsorption isotherms are studied to assay the structural effects of ethylene oxide (EO) and propylene oxide (PO) moieties on the molecular area and the interfacial tension behavior of molecules at the interface. Several industrial alcohols and isomerically pure alcohols, which have a general stucture of C4H9O(EO)m(PO)nH, are examined for their cosurfactant properties. They are high molecular weight alcohols and more surface active than the cosurfactants usually used. Results show that the number and the sequence of EO and PO units significantly affect the molecular areas and the interfacial tension (IFT) behavior of these molecules at the water/oil interface. The following conclusions are drawn from the result: 1) PO is more efficient in lowering the IFT and less effective in adsorption than EO. 2) For molecules having the same molecular weight but different structures, smaller molecules are more efficient in lowering the IFT. 3) When more EO, PO, or both units are added to the same hydrophobe, the molecule become bigger and more efficient in lowering the IFT.

PHOTOELECTRIC OBSERVATIONS AND PERIOD STUDY OF ECLIPSING BINARY VZ CEP

김천희,이재우,안영숙,한원용 한국우주과학회 1998 Journal of Astronomy and Space Sciences Vol.15 No.2

Photoelectric observations of the neglected eclipsing binary VZ Cep were made on four night during the observing season of 1984 at Sobaeksan Astronomy Observatory. The UBV light curves were secured incompletely with the gap in 0.35-0.75 phases. From the observations three times of minimum lights were determined in three band-passes, which formed one weighted minimum epoch (JD Hel 2446009.0453). With our observations, and improved light elements for VZ Cep is determined using all the photoelectric and CCD times of minimum lights published so far. The (O-C) resid-uals calculated with our light elements show small varying scatters which cannot be negligible. From the analyses of all the times of minima with the Scargle’s(1982)period-searching and a curve fitting methods, we found possible periodic oscillations of the (O-C) residuals with the period of 1. y26 and the amplitude of 0.d0032. These results, however, have to be considered as a preliminary values until complete analysis for the minimum lights of VZ Cep with enough observational data. Future observations of this binary system are urgently prompted.

입원환자 일반혀액검사 결과보고시간 단축

김천희,배태희,임규연,지현숙 한국의료QA학회 2005 가을학술대회 Vol.2005 No.1

Lamella body count와 foam stability index를 이용한 태아 폐성숙도 평가

김천희,서을주,민원기 대한임상검사정도관리학회 1994 臨床檢査와 精度管理 Vol.16 No.2

비이온계 계면활성제 수용액이 면직물의 습윤특성에 미치는 영향

김천희 한국의류학회 2001 한국의류학회지 Vol.25 No.8

Textile materials are frequently in contact with surfactant solutions during their manufacturing or finishing processes as well as cleaning processes in use. Liquid wetting, wicking, and absorbency of textile materials depend on the liquid properties, surface characteristics and pore geometry of textile materials, and the liquid-solid interactions. In this paper, 10 different nonionic surfactants, including Span20, Tween20, 40, 60, 80, 21, 61, 81, 65, 85, were used. The surfactants were characterized by their hydrophile-lipophile-balance (HLB) values, structures, and surface tensions. The 0.1g/dL and 1.0g/dL surfactant solutions, which were both above critical micelle concentration (CMC), were used to see the concentration effects on the wetting and absorbency of cotton fabrics. The wetting behavior and liquid retention properties of hydrophobic cotton fabrics with different nonionic surfactant solutions are reported. The contact angles are greatly decreased and the water retention values are greatly increased by adding most of the surfactants studied into the system. The extents of this effects are influenced by the characteristics of surfactants and its solutions. Hydrophilic surfactants which have low number of carbon atoms or unsaturated hydrophobe structures are more effective in improving the wetting and absorbancy of hydrophobic cotton fabrics. The water retention of hydrophobic cotton fabrics has positive relations with cos&, adhesion tension and work of adhesion. The 1.0g/dL surfactant solutions show similar, but -lightly improved wetting and absorbency characteristics of hydrophobic cotton fabrics compared to the 0.1g/dL surfactant solutions.

비이온계 계면활성제 수용액에서 polyester/cotton(65/35) 혼방직물의 습윤특성

김천희 韓南大學校 2007 論文集 (인문·사회·자연과학·공학) Vol.37 No.-

Span 20, Tween 20, 40, 60, 80, 21, 61, 81, 65, 85 등 10종의 비이온계 계면활성제 O.lgpdl 수용액이 polyester/cotton(65/35) 혼방직물의 습윤특성에 미치는 영향을 연구하였다. 계면활성제 첨가시 접촉각(θ)은 현저히 감소하나 수분보유량(W)과 수분보유량비(W/H)는 큰 변화가 없었다. 이는 순수에서의 시료 W/H가 매우 커서 계면활성제 첨가에 따른 효과를 확인할 수 없기 때문이라 생각된다. 친수기 구조가 동일할 경우 친유기 tail의 탄소수가 증가하면 θ가 증가하고, 친유기가 불포화 구조가 되면 접촉각이 감소하였다. 따라서 계면활성제의 친수성이 증가하면 접촉각이 감소하여 시료의 wetting에 효과적이며 친유기 구조의 불포화성은 친수성 증가와 동일한 효과를 갖는다. 본 시료의 습윤특성 향상에는 Span 20과 Tween 81이 가장 효과적이었고 계면활성제 수용액의 표면장력이 낮고 HLB(hydrophile lipophile balance)가 커서 친수성이 클수록 Cosθ 값이 증가한다 polyester/cotton 혼방직물의 접촉각은 polyester 직물과 cotton 직물의 접촉각의 사이 값을 나타내며, 계면활성제에 따른 습윤특성 변화는 유사한 경향을 보여준다. The effects of O.lgpdl nonionic surfactant solutions on water wetting/retention properties of polyester/cotton(65/35) fabric are reported. The following nonionic surfactants; i.e., Span 20, Tween 20, 40, 60, 80, 21, 61, 81, 65, & 85, are used in the study. The contact angles(θ's) are greatly decreased, however, the water retention ratio (W/H) values are not changed much by adding surfactants into the system. Hydrophilic surfactants which have low number of carbon atoms or unsaturated hydrophobe structures are more effective in improving the wetting properties of the fabric. Span 20 and Tween 81 are most effective. In general, surfactant solutions having low surface tension and high HLB values give high Cosθ's. The θ’s of polyester/cotton fabric show in between values of cotton and polyester fabrics.

한국산 사과의 당함량

김천희,최세영,김성자,장지원,윤광로 한국식품과학회 1996 한국식품과학회 학술대회 Vol.1996 No.1

비이온계 계면활성제 수용액이 PET직물의 습윤특성에 미치는 영향 (제2보) -계면활성제와 직물의 특성-

김천희 韓國衣類學會 2005 한국의류학회지 Vol.29 No.12

Span 20과 Tween 계 계면활성제의 물/공기 계면에서의 분자면적과 계면장력 거동

김천희 한국의류학회 2000 한국의류학회지 Vol.24 No.7

The molecular areas and the interfacial tension behavior of ten nonionic surfactants, i.e., Span 20 and Tween 20, 40, 60, 80, 21, 61, 81, 65, & 85 are tested to assay their effects on the wetting and liquid retention properties of hydrophilic and hydrophobic fibrous materials. The molecular areas at water/air interface are derived from Gibbs adsorption equations. The following conclusions are drawn from the results: 1) Span 20 is efficient in lowering the interfacial tension and effective in adsorption at the water/air interface, resulting in the low interfacial tension at critical micelle concentration(γ_CMC) and a small molecular area(ω), 2) when the hydrophiles of the surfactants are constant, ω's increase as hydrophobe carbon numbers of the surfactants increase, 3) when the hydrophobes are constant, γ_CMC's and ω's increase as the hydrophile ethylene oxide units increase, indicating. effectiveness and efficiency is parallel in this case, 4) the ethylene oxide unit length as a hydrophile has greater influence on co than the hydrophobe chain length.

유치원의 교재 ? 교구관리 프로그램의 설계 및 구현

김천희,박윤,윤삼중 한국콘텐츠학회 2006 한국콘텐츠학회논문지 Vol.6 No.12

The purpose of this study is to present a plan to design and utilize effectively useful software program in dealing with Teaching Materials and Tools Management in all infant education institute. This program is called Teaching Materials and Tools Management and it is based on the national kindergarten Curriculum notified by ministry of education. To achieve this goal, all teaching materials should be kept to classify and use easily regardless of their shape, kind, and maker(manufacturer). Teaching materials and tools once used in class should be kept after being repaired, And if it is difficult to repair them, write down detail information about them for any teacher to repair them easily. Teaching materials and tools should be classified efficiently after being used and registered to recognize their information at first glance. Teaching materials and tools should be registered with an index to manage curriculum effectively when establishing a year plan. 본 연구는 모든 유아 교육 기관의 교재교구 관리에 있어서 양질의 전산 관리 시스템을 용이하게 사용하도록 설계 및 구현하고, 이를 활용하는 방안을 제시하는데 그 목적을 두고 있다. 이를 위해 개발한 교재교구 관리를 위한 프로그램은 교육부 고시에 의한 제6차 유치원 교육 과정을 준거로 개발 범위를 한정하였다. 이런 목적을 달성하기 위하여 모든 교육 자료는 종류나 모양뿐만 아니라 구입한 시기와 만든 교사에 관계없이 교사들 모두가 쉽게 분류하고 사용하기에 편리하도록 보관할 수 있어야 하고, 유아 교육 현장에서 일단 사용한 교재교구는 다음의 현장 적용을 위하여 반드시 보수하여 보관하여야 하는데, 경우에 따라서 사용 후에 즉시 보수가 어려우면 그 교재 교구의 보수를 위한 정보를 자세하게 기록해 둠으로써 어느 교사가 보수 작업을 하더라도 쉽게 할 수 있도록 해야할 뿐 아니라, 제작 또는 구입하여 분류한 교재교구는 반드시 등록하여 그 자료에 관한한 모든 정보를 한 눈에 파악할 수 있어야 하며, 색인부를 만들어 교육계획 수립시에 사용함으로써 교육 과정의 운영 효과를 크게 기대할 수 있도록 해야 한다는 방침에 따라 설계하고 개발하였다.