• 대한화학회지
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• 제8권1호
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• pp.9-14
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• 1964

전해질용액의 점도가 농도의 양수임은 기지의 사실이나 전농도에 걸쳐 잘 맞는 관계식은 아직 발견되지 않았다. 표면장력 역시 이러한 관계가 있으나 완전한 식은 없으며 이들은 모두 용액내의 이온의 상태에 기인하므로 표면장력과 덤도간에도 일정한 관계가 있을 것으로 생각되는 바이다. 순수한 물질에 대한 관계식은 Silverman1)이 Batchinski식 과 MacLeod 식에서 ${\gamma}^{\frac{1}{4}}=\;A/{\eta}$ + B 식을 유도하여 실험오차 범위안에서 일치된다고 했으나 아직 $Jones^{(4)}$들이 측정한 몇가지 염을 제외하고는 거의 모든 염용액의 점도나 표면장력의 정밀한 값은 측정되지 않았음으로 우선 여기서는 몇가기 염용액의 점도를 측정하였고 또 점도계수와 농도관계를 고찰하였다.

• 한국자동차공학회논문집
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• 제12권2호
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• pp.62-68
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• 2004

To comply with stringent exhaust emission standards, it is necessary to reserch on some better quality of automotive fuels. Sulfur in fuels is sulfur compound by DOC and then it caused to the increase of PM on the surface of the catalyst. This research is focused on diesel emission characteristics and poisoning effect on Diesel Oxidation Catalyst when Ultra Low Sulfur Diesel(ULSD) and biodiesel are applied simultaneously. The biodiesel is used to improve viscosity of fuel specially in fuel injection system of engine since the introduction of ULSD may degrade viscosity in the process of desulfurization. Furthermore, this study may provide some basic data for the design of emissions reduction technology.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2009년도 추계학술대회 논문집
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• pp.250-253
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• 2009

In this study, the friction test was performed to find friction characteristics of advanced high strength steel (AHSS) sheets and the multiple regression method was employed to obtain friction models. The friction coefficients associated with the lubricant viscosity, drawing speed, and blank holding pressure are measured. Differently from GA steel sheets, the effects of the lubricant viscosity and pulling speed are a little, which are explained by a theory of adhesion and wear as well as a deformation of friction surface. In addition, the effects of friction parameters are numerically represented by friction regression models.

• 한국기계가공학회지
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• 제7권3호
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• pp.61-66
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• 2008

For the production of urethane prepolymer, the effect of process parameters such as diisocyanate MDI and polyol TDI was tested. In this paper, design of experiments has been adopted for studying the effect of the process parameters on the improvement of NCO and viscosity of pre-polymer. As a result of comparison of different parameters, the effect of polyol was stronger than that of isocyanate in comparison of reactivity according to the amounts of isocyanate and polyol. Especially, NCO and viscosity of pre-polymer affected a product safety.

• 대한기계학회논문집B
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• 제32권7호
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• pp.487-496
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• 2008

Quartz crystal oscillator is frequently used in measuring a very small amount of mass attached to or adsorbed on the surface of an electrode on the quartz plate. The physical principle is that the resonance frequency of the shear vibration of the quartz caused by an applied electric field is a function of the mass. Recently, effort has been tried to measure physical properties of viscoelastic fluids, such as viscosity and shear modulus. This paper presents useful formula that can be used in estimating the properties of viscoelastic fluids. Important finding in this analysis is that the formula can produce multiple values for the physical properties of the viscoelastic materials.

• 에너지공학
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• 제7권2호
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• pp.180-186
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• 1998

본 연구에서는 벤토나이트 혼합액의 유동특성 등을 파악하기 위형 전단속도에 따른 점도의 변화를 측정하였으며, 박막형성에 관한 특성을 파악하기 위하여 혼합비 및 점도에 따른 박막두께를 측정하였다. 또한 건조 후 박막이 박막의 두께에 따른 오염표면에서 분리되는 특성을 조사하였으며 벤토나이트의 흡착성능에 영향을 미치는 비표면적을 측정하기 위하여 BET 방법을 이용하였다. 점도는 혼합비의 증가에 따라 감소하였으며 건조박막의 두께는 혼합비가 증가할수록 두꺼워진다. 건조박막의 분리특성은 혼합비가 5에서 10% 이내로 박막이 40에서 150$\mu\textrm{m}$가 적당하다.

• 약학회지
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• 제35권4호
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• pp.277-282
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• 1991

Rheological, colloidal and micromeritical properties were followed to investigate aging mechanisms of hydrous aluminum oxide suspension using Zeta-meter systems, BET adsorption apparatus, Master sizer and electronmicroscope. The results indicate that hydrous aluminum oxide suspension revealed plastic flow with thixotropy. The viscosity, thixotropy and yield value were increased with increasing concentration. During aging process, the viscosity and thixotropic index were increased by an addition of glycerin, however, sorbitol stabilized aging process of the suspension being accompanied with growth of particle size and reduction in specific surface area, pore area and pore volume, and consistency. Diminution of adsorptive power of the particles was also protected by addition of sorbitol to hydrous aluminum oxide suspension. From these results, one of aging mechanism of hydrous aluminum oxide suspension assumed growth and/or crystallization of colloidal particles in aqueous suspension.

• 반도체디스플레이기술학회지
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• 제4권2호
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• pp.21-24
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• 2005

Ink-jetting characteristics of pulse width and pulse amplitude for a piezoelectric ink jet printer driver have been mapped with various polymer EL ink. In this study, the jetting characteristics have been classified into 4 regime; no Jetting, unstable jetting, stable jetting, and spraying, and the importance of fluid viscosity on the scope of the stable jetting regime has been emphasized. The relation between jetting speed and the width and amplitude of driving signal has also been investigated and the effect of the speed on the jetting characteristics has been discussed.

• 한국안전학회지
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• 제3권1호
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• pp.15-19
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• 1988

The falling ball viscometer has been widely used for measuring the viscosity of the Newtonian fluids because of its simple theory and low cost. The use of the falling ball viscometer for measuring the non-Newtonian viscosity has been of interest to rheologists for some years. The analysis of the experimental results in a falling ball viscometer rest on Stokes law which yields the terminal velocity for a sphere moving through an infinite medium of fluids. An attempt to use the falling ball viscometer to measure the non-Newtonian viscosity in the intermediate shear rate ranEe was sucessfully accomplished by combining the direct experimental obserbations with a simple analytical model for the average shear-stress and shear rate at, the surface of a sphere. In the experiments with highly viscoelastic polyacrylamide solutions the terminal velocity was observed to be dependent on the time interval between the dropping of successive balls. The time-dependent phenomenon was used to determine characteristic diffusion times of the concentrated solutions of polyacrylamide.

• Korean Chemical Engineering Research
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• 제52권4호
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• pp.516-521
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• 2014

고점성이며 낮은 표면장력 매체로 구성된 기포탑에서 축방향 국부 열전달 계수와 총괄 열전달 계수에 대해 고찰하였다. 기체공탑유속(0.02~0.10 m/s), 액체 점도($0.1{\sim}0.3Pa{\cdot}s$) 그리고 액체 표면장력($66.1{\sim}72.9{\times}10^{-3}N/m$)이 국부 및 총괄 열전달 계수에 미치는 영향을 검토하였다. 열전달 영역은 기포탑 내부 열원과 기포탑 간의 열전달계로 구성하였다. 즉, 기포탑의 중앙에 수직 열원을 설치하여 내부 열원으로 하였다. 열전달 계수는 주어진 운전조건에서 열원에 제공되는 열량과 내부 열원과 기포탑 간의 온도차를 연속적으로 측정하여 결정하였다. 국부 열전달 계수는 기체공탑유속이 증가함에 따라 증가하였으나 기체 분산판으로 부터의 축방향 거리가 증가함에 따라, 액체의 표면장력이 증가함에 따라 감소하였다. 총괄 열전달 계수는 기체공탑유속이 증가함에 따라 증가하였으나 액상의 점도와 표면장력이 증가함에 따라서는 감소하였다. 총괄 열전달 계수는 기체공탑유속, 액상의 점도와 표면장력의 함수로 상관계수 0.91의 상관식을 얻을 수 있었으며 넛셀 수, 레이놀즈 수, 플란틀 수 그리고 웨버 수의 함수로 상관계수 0.92의 상관식으로 나타낼 수 있었다. $$h=2502U^{0.236}_{G}{\mu}^{-0.250}_{L}{\sigma}^{-0.028}_L$$ $$Nu=325Re^{0.180}Pr^{-0.067}We^{0.028}$$.