• Elastomers and Composites
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• v.41 no.1
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• pp.10-18
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• 2006

Influence of low molecular weight polybutadiene (liquid PB) treated with maleic anhydride on properties of a silica-filled SBR compounds was studied. Silica dispersion was improved by adding liquid PB. The liquid PB treated with maleic anhydride (liquid MAPB) was found to be more effective for the improvement of silica dispersion than the liquid PB without maleic anhydride (liquid NPB). Viscosity of the SBR compound decreased by adding the liquid PB. The crosslink density decreased with increase of the liquid PB content and the cure rate became slower with increasing the liquid PB content. Considering the experimental results, it was believed that addition of small amount of the liquid PB (less than 5 phr) was desirable to improve properties of silica-filled SBR compounds.

• KSBB Journal
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• v.7 no.1
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• pp.59-65
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• 1992

Hydrodynamics and mixing characteristics such as circulation time, mixing time, circulation velocity and axial dispersion coefficient were investigated using highly viscous pseudoplastic solutions of carboxymethyl cellulose(CMC) in an external circulation loop air-lift reactor with 13$\ell$ working volume. The superficial gas velocity was changed from 1.9 to 6.2cm/s and CMC concentration from 0 to 1.0wt%. The theoretical model based on the pressure balance is developed mathematically to predict liquid circulation velocity. Gas hold-up, circulation velocity and axial dispersion coefficient of liquid phase increased with increasing gas velocity and decreased slightly with increasing liquid viscosity. Mixing time and circulation time decreased with increasing gas velocity and increased with increasing liquid viscosity. Experimental data on liquid circulation velocity were in good agreement with the predicted values.

• Journal of Microbiology and Biotechnology
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• v.17 no.4
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• pp.600-603
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• 2007

The effect of a water-miscible ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate $([BMIM][BF_4])$, on the horseradish peroxidase (HRP)-catalyzed oxidation of 2-methoxyphenol (guaiacol) with hydrogen peroxide $(H_2O_2)$ was investigated. HRP maintains its high activity in the aqueous mixtures containing various concentrations of the ionic liquid and even in 90% (v/v) ionic liquid. In order to minimize the effect of solution viscosity on the kinetic constants of HRP catalysis, the enzymatic reactions in the subsequent kinetic study were performed in water-ionic liquid mixtures containing 25% (v/v) ionic liquid at maximum. As the concentration of $[BMIM][BF_4]$ increased for the oxidation of guaiacol by HRP, the $K_m$ value increased with a slight decrease in the $K_{cat}$ value: The $K_m$ value increased from 2.8 mM in 100% (v/v) water to 22.5mM in 25% (v/v) ionic liquid, indicating that ionic liquid significantly weakens the binding affinity of guaiacol to HRP.

• Journal of the korean Society of Automotive Engineers
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• v.6 no.1
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• pp.46-54
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• 1984

We applies Molecular Dynamics simulation technics to a system of Lennard-Jones potential interacting Argon liquid to study shear flow behavior. The thermodynamic state of the system is .rho.=35.54 Kg, mole/m$^{3}$, T=86.5.deg. K which is the triple point of Argon liquid. We applies shear rate : .epsilon.=9.26*10$^{9}$ 1/sec in the system. We find the response function, shear viscosity changes, and shear rate build-up as a function of time. We also find the thermal conductivity in a soft-sphere system.

• Journal of ILASS-Korea
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• v.6 no.4
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• pp.14-21
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• 2001

Rotary atomizer is widely used in practical application ranging from combustion, cooling, spray drying, agriculture, chemical system. Rotary cup atomizer has some advantages such as extreme versatility and liquid atomization successfully varying widely in viscosity. In rotary atomization, the feed liquid is centrifugally accelerated to high velocity and the liquid extends over the rotating surface as a thin film before being discharged into an atmosphere. The degree of rotary atomization depends upon peripheral speed, feed rate, liquid properties and atomizer design. An important asset is that thickness and uniformity of the liquid sheet can readily be controlled by regulating the liquid flow rate and the rotational speed. LDPA(Laser Diffraction Particle Analyser) and image aquisition system are used to measure drop size distribution and spray pattern. The atomization characteristics of the rotary cup atomizer is investigated experimentally by varing the liquid feed rate, rotary cup speed and air velocity for atomization. As a results, the effect of air velocity on the atomization characteristics such as drop size and spray uniformity is considerably greater than variation of those with liquid feed rate.

• Journal of Mechanical Science and Technology
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• v.20 no.2
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• pp.271-277
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• 2006

A numerical study is made of the spin-up from rest of a three-layer fluid in a closed, vertically-mounted cylinder. The densities in the upper layer $\rho_1$, middle layer $\rho_2$ and lower layer $\rho_3\;are\;\rho_3\;>\;\rho_2\;>\;\rho_1$, and the kinematic viscosities are left arbitrary. The representative system Ekman number is small. Numerical solutions are obtained to the time-dependent axisymmetric Navier-Stokes equations, and the treatment of the interfaces is modeled by use of the Height of Liquid method. Complete three-component velocity fields, together with the evolution of the interface deformations, are depicted. At small times, when the kinematic viscosity in the upper layer is smaller than in the middle layer, the top interface rises (sinks) in the central axis (peripheral) region. When the kinematic viscosity in the lower layer is smaller than in the middle layer, the bottom interface rises (sinks) in the periphery (axis) region. Detailed shapes of interfaces are illustrated for several cases of exemplary viscosity ratios.

• Journal of Korean Society for Atmospheric Environment
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• v.32 no.4
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• pp.349-359
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• 2016

Researchers have traditionally assumed that aerosol particles containing secondary organic aerosols (SOAs) are to be in liquid state with low viscosity even at low relative humidity. However, recent measurements showed that SOAs can have high viscosity under certain conditions. Herein, new different techniques for measurements of viscosities of SOA particles are introduced. Moreover, laboratory studies for the viscosities and the phases of biogenic SOAs produced by ${\alpha}$-pinene, isoprene, limonene, and ${\beta}$-caryophyllene of atmospheric relevance are reviewed. Future studies for determination of the phases of atmospheric aerosol particles are also suggested.

• Proceedings of the Korean Fiber Society Conference
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• 2003.04a
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• pp.223-226
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• 2003

Due to the potential application to ultra-high strength fibers and excellent properties such as high mechanical properties, excellent thermal endurance and chemical stability, thermotropic liquid crystal polymers (TLCPS) are attractive in recent years [1, 2]. Furthermore, the melt blends of TLCPS and conventional thermoplastics have been extensively investigated because of their easy processing and high performance [3-6]. Since high performance polymers generally has high melt viscosity, introduction of the relatively low viscosity components may be one of the more effective techniques to improve processability through the decrement of melt viscosity in melt processing. (omitted)

• Bulletin of the Korean Chemical Society
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• v.32 no.11
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• pp.3909-3913
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• 2011

In this paper we have carried out molecular dynamics simulations (MD) for model systems of liquid n-alkane oligomers ($C_{12}{\sim}C_{80}$) at high temperatures (~2300 K) in a canonical ensemble to calculate viscosity ${\eta}$, self-diffusion constants D, and monomeric friction constant ${\zeta}$. We found that the long chains of these n-alkanes at high temperatures show an abnormality in density and in monomeric friction constant. The behavior of both activation energies, $E_{\eta}$ and $E_D$, and the mass and temperature dependence of ${\eta}$, D, and ${\zeta}$ are discussed.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.04a
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• pp.457-462
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• 1999

The purpose of this study is to design the requirements for the materials of stabilizing slurry and to determine the optimum slruuy mix design used in the underground wall of Inchon LNG #213 and 214 tank. After the materials and mix conditions of stabilizing slurry investigated and tested, we propose materials and optimum mix design according to testing items including funnel viscosity, we propose materials and optimum mix design according to testing items including funnel viscosity, fluid loss, cake thickness and specific gravity. As this results, we select optimum mix design that the upper limit ratio of bentonite is 2.0%, polymer is 0.1% considering the funnel viscosity and dispersion agent is 0.05% considering the fluid loss. Also we select all materials which are composed of GTC4 as bentonite, KSTP as polymer and Bentocryl as dispersion agent. All test results are satisfied our specifications for stabilizing slurry.