• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2002년도 proceedings of the second asia international conference on tribology
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• pp.143-144
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• 2002

A series of alcohols with perfluorinated segments $F(CF_2)_m(CH_2)_n-OH$, with m=8, 10 and n=4, 6, 10, were synthesized. First, the alcohols were reacted with fatty acid to produce several esters $(F(CF_2)_m(CH_2)-OOC-R$ with m=8, 10 and n=2, 4, 8,) containing perfluoro group by condensation reaction, and characterized by FT-IR, GC, and surface tension. The esters were soluble in ethyl ether, toluene, hexane, ethyl acetate, chloroform, and acetone, but insoluble in methyl alcohol, ethyl alcohol and isopropyl alcohol. Preliminary experiments on 1,2-dichloroethane solutions showed a remarkable decrease of surface tension upon addition of the esters. Also, the esters films ranged from 100 to $122^{\circ}$, depending on the structure of fatty acid esters. As the separate experiment, the water-repellency of coated paper and cotton was evaluated. As a result, the water droplet dropped in surface was not permeated for two weeks.

• 약학회지
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• 제42권3호
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• pp.284-289
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• 1998

The effect of reaction condition, solvent addition and thermal treatment on the bulk density, crystallinity and chemical properties of the freeze-dried cefazohn sodium was inves tigated to prepare the cefazolin sodium powder for injection with good flowability. Crystalline cefazolin sodium powder with high untapped-bulk density (about 45%) and low compressibility (about 40%) was obtained by solvent addition to the very highly concentrated cefazohn sodium solution followed by subsequent thermal treatment before freeze-drying. The desirable solvent was low substituted alcohol such as isopropyl alcohol and anhydrous ethanol with the final concentration of about 9%. The pH adjustment and nitrogen gas purging during the reaction did not give significant effect on the chemical properties such as content, color, transmittance and pH of the reconstituted cefazolin sodium aqueous solution.

• 한국세라믹학회지
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• 제30권8호
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• pp.623-628
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• 1993

Lead monoxide has two phases at room temperature. One is a yellow orthorhombic phase, the other is a redtetragonal phase. Sometimes two phases are hybrided. The specificity of phase transitions of lead oxide is found during the milling of the batch including lead oxide. The pure orthorhombic phase of PbO can be transformed to the tetragonal phase perfectly by wet ball milling (milling liquid is distilled water) without thermal energy. However, when ethyl alcohol, isopropyl alcohol and aceton are used as milling liquid, respectively, the hybrid form of orthorhombic andtetragonal phases is obtained by wet ball milling. From the hybrid form heat-treated at $600^{\circ}C$ for 3hrs, this work results that mechanical phase transition of orthorhombic phase make a new form as distorted type orthorhombic phase of PbO.

• 한국식품과학회지
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• 제30권6호
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• pp.1247-1251
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• 1998

식초의 에탄올과 초산을 동시에 분석하고자 packed column으로 gas chromatographic analysis을 모색하였다. Tenax-GC를 충진물로 사용하여 $2\;m{\times}2\;mm$의 stainless steel column을 제조하고 식초를 여과하여 column에 직접 주입한 결과 내부 표준 물질로 사용한 isopropyl alcohol과 에탄올, 초산이 20분 이내에서 완전히 분리되었으며 정확도가 매우 높은 것으로(P<0.05)나타났다. 19종의 식초를 이용하여 적정방법으로 산도를, packed column GSC로 에탄올과 초산을, HPLC로 초산을, capillary column GLC로 에탄올과 초산을 각각 분석하여 분석치들을 상호 비교하였다.

• Bulletin of the Korean Chemical Society
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• 제21권8호
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• pp.817-822
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• 2000

Crack-free hard coating siIica films were prepared by sol-gel processfrom twokinds of silicon alkoxide (tetra-ethoxysilane and methyltrimethoxysilane) and two kinds of alcohol (methanol and isopropyl alcohol) with an acid catalyst,acetic acid. A silicate framework of the precursor solution was investigated by infrared spectros-copy (IR) in the process of hydrolysis and condensation. Theextent of the condensation in the intermediates was elucidated by gel permeation chromatography (GPC) and 29Si-NMR spectroscopy. The hard coating films werecharacterized by IR,scanning electron microscope (SEM), thermo gravimetric analyzer (TGA) and dif-ferential scanning calroimeter (DSC). The synthetic condition for the crack-free and transparent silica film for-mation was optimized interms of starting materials for the precursor solution as well as preparation method of the silica film.

• 한국식품영양과학회지
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• 제32권4호
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• pp.526-530
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• 2003

각기 다른 염농도에서 염장한 오이의 이화학적 특성을 조사하였다. 염장시 첨가되는 염농도가 높을수록 수축현상이 심하였으며, 오이의 염농도는 염장 30일경에 30% 처리구를 제외한 모든 처리구에서 이론치와 유사한 농도를 나타내었다. pH의 경우 25%처리구는 염장 120일까지 감소 경향을 보인 반면 30%처리구는 60일이후부터 거의 변화가 없었다. 오이 표면의 녹색도는 염장 10일까지는 모든 처리구에서 녹색(-1.33~-2.87)이 유지되었으나 염장기간이 경과함에 따라 적색으로 변하였고, 이러한 현상은 염농도가 낮을수록 심하였다. 황색도는 염농도가 낮은 15% 첨가구가 염장 전기간에 걸쳐 가장 높은 황색도(6.15~12.52)를 보였다. Isopropyl alcohol 추출색소액 중 생오이의 색소추출액은 439, 473, 632 nm에서 피크를 나타낸 반면 염장오이는 염장초기 첨가된 염농도에 관계없이 생오이 색소추출액과는 다른 흡광도 변화를 나타내어 410, 505, 538, 607, 565 nm에서 새로운 피크를 형성하였다. 경도는 염농도에 관계없이 저장기간이 경과함에 따라 지속적으로 상승하였다.

• 한국산학기술학회논문지
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• 제17권7호
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• pp.641-647
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• 2016

피에조 DOD(drop-on-demand) 잉크젯 프린팅 방식은 다양한 종류의 잉크를 사용할 수 있기 때문에 최근에 첨단 산업에 적용이 활발히 연구되고 있다. 피에조 잉크젯 헤드에서 토출되는 액적의 형성 과정을 VOF(Volume-of-Fluid) 기법을 이용한 전산해석으로 예측하고 이를 측정결과와 비교하였다. 작동유체는 에틸렌 글리콜 50%와 IPA(Isopropil alchol) 50%의 혼합액을 사용하였다. 노즐 출구에서 메니스커스 변위의 시간에 따른 변화를 직접 측정하여 노즐 입구의 속도분포를 예측하고 이를 해석의 초기조건 입력자료로 사용하였다. 측정치와 해석치를 비교한 결과 전산해석이 측정치의 액적 형성 과정을 잘 예측함을 알 수 있었다. 주액적 형성과정보다 위성액적 형성과정 예측에 오차가 약간 컸는데, 이는 정지중의 공기에 큰 질량의 주액적이 날아가는 것을 예측할 때는 해석오차가 적지만 주액적에 의해서 주변 공기 유동이 활발해진 상태에서 적은 질량의 위성액적이 날아가는 것을 예측할 때는 해석오차가 상대적으로 커지기 때문이다. 또한 에틸렌 글리콜과 IPA의 혼합 비율을 달리하여 물성치를 변화시킨 다른 잉크에 대해서도 잉크 액적 형상을 예측한 결과 실험 결과를 비교적 정확히 예측할 수 있었다.

• Mass Spectrometry Letters
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• 제3권3호
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• pp.68-73
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• 2012

Fat malabsorption is an important cause of poor growth in infancy and childhood. Steatorrhea tests have been developed using various methods. Traditional measurements of stool fat, however, require large samples and it often takes as a week to complete the analysis. In this paper, a liquid chromatography-electrospray ionization/mass spectrometry (LC-ESI/MS) method was developed for simultaneous quantitative analysis of triacylglycerols, triolein, diolein and monoolein, in mouse feces. Moreover, the procedure was rapid, simple as well as compatible with LC-ESI/MS. Chloroform-isopropyl alcohol solution was used for fat-soluble sample extraction. After centrifugation and filtration, an analytical solution was prepared. Triolein, diolein and monoolein were separated using non-aqueous reversed-phase column with the mobile phase consisting of A (methanol) and B (acetone-isopropyl alcohol). The precision (% CV) and accuracy (% bias) of the assay were 3.8-14.7% and 85.2-114.9%, respectively. This method has been successfully applied to simultaneous determination of triolein, diolein and monoolein in feces from 30 mice. This method can therefore be applied to measure triacylglycerols in mouse feces accurately and precisely by LC-ESI/MS, thereby helping to predictive biomarker in fat malabsorption and diagnostic research.

• 한국재료학회지
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• 제16권2호
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• pp.99-105
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• 2006

This paper reports an improved bonding method using the IPA (isopropyl alcohol) assisted low-temperature bonding process for the PMMA (polymethylmethacrylate) micro CE (capillary electrophoresis) chip. There is a problem about channel deformations during the conventional processes such as thermal bonding and solvent bonding methods. The bonding test using an IPA showed good results without channel deformations over 4 inch PMMA wafer at $60^{\circ}C$ and 1.3 bar for 10 minutes. The mechanism of IPA bonding was attributed to the formation of a small amount of vaporized acetone made from the oxidized IPA which allows to solvent bonding. To verify the usefulness of the IPA assisted low-temperature bonding process, the PMMA micro CE chip which had a $45{\mu}m$ channel height was fabricated by hot embossing process. A functional test of the fabricated CE chip was demonstrated by the separation of fluorescein and dichlorofluorescein. Any leakage of liquids was not observed during the test and the electropherogram result was successfully achieved. An IPA assisted low-temperature bonding process could be an easy and effective way to fabricate the PMMA micro CE chip and would help to increase the yield.

• 한국분말재료학회지
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• 제23권4호
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• pp.311-316
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• 2016

$Ni(OH)_2$ hollow spheres have been prepared by solvent displacement crystallization using a micro-injection device, and the effect of process parameters such as concentration and the relative ratio of the injection speed of the precursor solution, which is an aqueous solution of $NiSO_4{\cdot}6H_2O$, to isopropyl alcohol of displacement solvent have been investigated. The crystal phases after NaOH treatment are in the ${\beta}-phase$ for all process parameters. A higher concentration of $NiSO_4{\cdot}6H_2O$ aqueous solution is injected by a micro-injection device and bigger $Ni(OH)_2$ hollow spheres with a narrower particle size distribution are formed. The crystallinity and hardness of the as-obtained powder are so poor that hydrothermal treatment of the as-obtained $Ni(OH)_2$ at $120^{\circ}C$ for 24 h in distilled water is performed in order to greatly improve the crystallinity. It is thought that a relative ratio of the injection speed of $NiSO_4{\cdot}6H_2O$ to that of isopropyl alcohol of at least more than 1 is preferable to synthesize Ni(OH)2 hollow spheres. It is confirmed that this solution-based process is very effective in synthesizing ceramic hollow spheres by simple adjustment of the process parameters such as the concentration and the injection speed.