• Journal of Institute of Control, Robotics and Systems
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• v.12 no.12
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• pp.1191-1196
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• 2006

In this work the kinetics of volume changes of fluid spaces associated with infusion of Ringer's solution are analyzed using the body fluid space model. During infusion of Ringer's solution, the human body is assumed to be characterized by the fluid space model into which fluid is fed and from which fluid is left. Various infusion types were tested to accommodate different medical situations. Volunteers were given Ringer's solution and the changes in blood hemoglobin were detected. From the comparison with experimental data, the single- and two-fluid space models were found to represent adequately the kinetics of human volume expansion during infusion of Ringer's solution.

• Bulletin of the Korean Chemical Society
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• v.33 no.7
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• pp.2260-2264
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• 2012

The kinetics and mechanism of the pyridinolysis ($XC_5H_4N$) of dimethyl isothiocyanophosphate are investigated in acetonitrile at $55.0^{\circ}C$. The Hammett and Br$\ddot{o}$nsted plots for substituent X variations in the nucleophiles exhibit two discrete slopes with a break region between X = 3-Ac and 4-Ac. These are interpreted to indicate a mechanistic change at the break region from a concerted to a stepwise mechanism with a rate-limiting expulsion of the isothiocyanate leaving group from the intermediate. The relatively large ${\beta}x$ values imply much greater fraction of frontside nucleophilic attack TSf than that of backside attack TSb. The steric effects of the two ligands play an important role to determine the pyridinolysis rates of isothiocyanophosphates.

• Macromolecular Research
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• v.11 no.5
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• pp.311-316
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• 2003

The kinetics of photoinitiated polymerization of dimethacrylate macromonomers have been studied to determine the diffusion-controlled reaction parameters using attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR). A predicted kinetic rate expression with a diffusion control factor was employed to estimate an effective rate constant and to define the reaction-controlled and diffusion-controlled regimes in the photopolymerization. An effective rate constant, k$_{e}$, can be obtained from the predicted kinetic rate expression. At the earlier stages of polymerization, the average values of kinetic rate constants do not vary during the reaction time. As the reaction conversion, $\alpha$, reaches the critical conversion, $\alpha$$_{c}$, in the predicted kinetic expression, the reaction becomes to be controlled by diffusion due to the restricted mobility of dimethacrylate macromonomers. A drop in value of effective rate constant causes a drastic decrease of reaction rate at the later stages of polymerization. By determining the effective rate constants, the reaction-controlled and diffusion-controlled regimes were properly defined even in the photopolymerization reaction system.m.m.

• Journal of Magnetics
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• v.10 no.4
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• pp.152-156
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• 2005

Effects of the disproportionating hydrogen pressure and alloy composition on the texture in the HDDR-treated Nd-Fe-B particles were examined using the $Nd_{12.6}Fe_{81.4}B_6$ and $Nd_{12.6}Fe_{68.7}B_6Co_{11.0}Ga_{1.0}Zr_{0.l}$ alloys. Disproportionation kinetics of the $Nd_2Fe_{14}B$ phase in the Nd-Fe-B alloy was retarded significantly by the addition of Co, Ga and Zr. The retarded disproportionation kinetics of the $Nd_2Fe_{14}B$ phase ensured a wider processing win­dow in terms of disproportionating hydrogen pressure for achieving a texture in the HDDR-treated Nd-Fe-B alloy particles.

• Korean Journal of Microbiology
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• v.28 no.3
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• pp.264-267
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• 1990

The objectives of the current studies were to establish the optimal conditions for the production of extracellular protease inhibitor in a strain of Streptomyces fradiae. As results, it was found that cell specific growth rate was very critical for the production of protease inhibitor and the optimum specific growth rate was found to be 0.05 h$^{-1}$ . Dissolved oxygen tension and pH were also important to regulate the inhibitor production. The inhibitory mode of the purified inhibitor to .alpha.-chymotrypsin was found to be competitive (K$_{i}$=5.5*10$^{-7}$ M). One mole of inhibitor could bind two moles of .alpha.-chymotrypsin and the complex has very low dissociation constant.t.

• Journal of the Korean Ceramic Society
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• v.30 no.11
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• pp.974-978
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• 1993

Glass viscosity effects on the electrical properties and microstructure of RuO2 based thick film resistors (TFR) using alumina modified lead borosilicate glasses were studied. AT 85$0^{\circ}C$, the glass viscosities were increased from 4.24Pa.s to 51.5Pa.s when the alumina was added from none to 14 weight percent to the standard glass of 63% PbO, 25% B2O3 and 12% SiO2. The resistivities of resistors were generally decreased and the microstructure development was retarded as the viscosity of the glass increased. This is contrary to the generally accepted thought that the low resistivity is due to fast microstructure development kinetics in TFR. Even though the glass viscosity retards the microstructure development kinetics, the overall network formations are favored for higher viscosity of glass, such that the sheet resistivities were decreased as the glass viscosity increased.

• Proceedings of the KAIS Fall Conference
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• 2004.11a
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• pp.280-283
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• 2004

Effect of H2 spillover rate as function of reduction temperature on reaction kinetics was evaluated. Reaction kinetics including yield, conversion, activation energy and selectivity of 1-butene isomerization over Pt/HxMoO/SiO were measured as reaction temperature was increased. While conversion of 1-butane was decreased, yield of iso-butene was increased. Two kinds of reaction mechanism were proposed from the change of selectivity as function of temperature.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.282-283
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• 2006

Densification behavior of nano-agglomerate powder during pressureless sintering of Fe-Ni nanopowder was investigated in terms of diffusion kinetics and microstructural development. To understand the role of agglomerate boundary for sintering process, densification kinetics of Fe-Ni nano-agglomerate powder with different agglomerate size was investigated. It was found that activation energy for densification was lower in the small-sized agglomerate powder. The increase in the volume fraction of inter-agglomerate boundary acting as high diffusion path might be responsible for the enhanced diffusion process.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.70-71
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• 2006

Growth behavior and kinetics of grains in a liquid matrix has been studied by computer simulation for various physical and processing conditions. The kinetics of growing and dissolving grains were considered to follow those of single crystals in a matrix. Depending on the shape of crystals, rounded or faceted, different kinetic equations were adopted for growing grains and an identical equation for dissolving grains. Effects of such critical parameters as step free energy, temperature, and liquid volume fraction were evaluated.

• Journal of Pharmaceutical Investigation
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• v.23 no.4
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• pp.207-211
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• 1993

Reservoir type devices were designed for long-term implantable drug delivery system. The reservoir type device was prepared with the polymethacrylic acid gel coated with polyurethane membrane. Release controlling agent (RCA) were employed to control drug release from devices via generation of micropores in the membranes. The polyurethane membrane functioned as a rate controlling barrier. The drug release pattern of hydrogel demonstrated zero order kinetics. The release rate of drugs could be regulated by varying hydrophobicity/hydrophilicity and content of the RCA, as well as the thickness of the polyurethane membrane. The release of drugs from this system was governed by pore mechanism via simple diffusion and osmotic pressure.