• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2002.12a
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• pp.126-129
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• 2002

An intelligent digital redesign technique (IDR) for the observer-based output feedback Takagi-Sugeno (T-5) fuzzy control system with fuzzy outputs is developed. The considered IDR condition is cubically parameterized as convex minimization problems of the norm distances between linear operators to be matched.'rho stability condition is easily embedded and the separations principle is explicitly shown.

• KSBB Journal
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• v.6 no.2
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• pp.215-222
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• 1991

The experimental investigations about ultrafiltration(UF) of bovine serum albumin(BSA) solutions were conducted with a batch stirred cell. This study was investigated on the permeate flux. The experiment was carried out at pH 4.8. Protein concentrations were measured spectrophotometrically. For very dilute samples, a Lowry method was used. In the ultrafiltration of dilute BSA solutions, the permeate flux according to working time was decreased smoothly and at isoelectric point, concentration polarization of BSA solution was ignored at limited working pressures by magnetic stirring.

• KSBB Journal
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• v.18 no.1
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• pp.65-69
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• 2003

Two molecular imprinted polymers (MIPs) were prepared by using pentoxifylline and a mixture of caffeine-theophylline (2:1, mole ratio) as the templates, MAA as the monomer, and EDMA as the crosslinker The obtained polymer particles (particle size 25-35 $\mu\textrm{m}$) were packed into a HPLC column (150$\times$3.9mm). The selectivity and chromatographic characterization of the imprinted polymers were studied using pentoxifylline, caffeine, theophylline, theobromine as samples and acetonitrile as the mobile phase, Both imprinted polymers showed increased affinity for structural analogues. By using a mixture of caffeine-theophylline templates MIPs, good separations of caffeine, theobromine and theophylline were obtained, and pentoxifylline and caffeine were partly separated.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.51 no.12
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• pp.664-669
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• 2002

In this paper the method to determine tire optimal switching instants in order to reduce the transient surges during switching not relevant to the neutral treatment of shunt reactors is presented. This method consists of the following two steps. First, the instants of the voltage peaks between the contacts of each poles and the voltage magnitude as well as the moments of the current zero crosses were found out analytically. Next, the instants of the contact touches or separations were determined in consideration of the rate of decrease of dielectric strength or a circuit breaker and the variation of the its operating time. The results obtained from the EMTP(Electromagnetic Transient Program) analysis studies show that the making instants are established at the peak voltage of each three poles for any conditions of a neutral point and the possible upper limited values of inrush currents due to the variation of the mechanical operating time can be estimated.

• Journal of Biomedical Engineering Research
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• v.15 no.1
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• pp.35-40
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• 1994

A probe was designed to study the relationship of photon flux path and layered properties of bilogical tissue. The result shows that different wavelengths have different flux path and maximum reflectance position with separation. The source-detector separations on maximum reflectance of IR and GR were 7.5 mm and 2.5 mmm each other and layered properties of tissue can be discriminated bye the change of S-D separation using designed probe.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.12 no.11
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• pp.873-881
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• 2002

The fluid induced vibration (FIV) phenomena of an equivalent airfoil system of MAV have been investigated in low Reynolds number flow region. Unsteady flows with viscosity are computed using two-dimensional incompressible Navier-Stokes equations. The present fluid/structure interaction analysis is based on one of the most accurate computational approach with computational fluid dynamics (CFD) and computational structural dynamics (CSD) techniques. The highly nonlinear fluid/structure interaction phenomena due to severe flow separations have been analyzed for the low Reynolds region that has a dominancy of flow viscosity. The effects of Reynolds number and initial angle of attack on the fluid/structure coupled vibration instability are shown and the qualitative trend of FIV phenomenon is investigated.

• Coupled systems mechanics
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• v.6 no.1
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• pp.75-96
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• 2017

As electron donor/acceptor materials for organic photovoltaic cells, small-molecules donors/acceptor are attracting more and more attention. In this work, we investigated the electronic structures, electrochemical properties, and charge carrier transport properties of four recently-synthesized small-molecule donors/acceptor, namely, DPDCPB (A), DPDCTB (B), DTDCPB (A1), and DTDCTB (B1), by a series of ab initio calculations. The calculations look into the electronic structure of singly oxidized and reduced molecules, the first anodic and cathodic potentials, and the electrochemical gaps. Results of our calculations were in accord with those from experiments. Using Marcus theory, we also computed the reorganization energies of hole/electron hoppings, as well as hole/electron transfer integrals of multiple possible molecular dimer configurations. Our calculations indicated that the electron/hole transport properties are very sensitive to the relative separations/orientations between neighboring molecules. Due to high reorganization energies for electron hopping, the hole mobilities in the molecular crystals are at least an order of magnitude higher than the electron mobilities.

• Bulletin of the Korean Chemical Society
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• v.7 no.1
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• pp.45-50
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• 1986

Separation of optical isomers of some derivatives of amino acids by reversed-phase HPLC has been accomplished by adding a chelate of an optically active amino acid to copper(Ⅱ) to the mobile phase. Cu(Ⅱ) complexes of L-proline and L-hydroxyproline in the mobile phase showed different degrees of separation. Optical isomers of DNS derivatives of amino acids are selectively separated, but those of several other derivatives are not at all. The kinds of buffer agents, the pH, and the concentrations of acetonitrile and the Cu(Ⅱ) ligand all affect the separations. The elution behavior between D and L DNS-amino acids appears to depend on the alkyl side chain of the amino acids. A chromatographic mechanism is proposed that is based on a stereospecificity of the formation of ternary complexes by the D, L-DNS-amino acids and the chiral additive associated with the stationary phase. The steric effects of the ligand exchange reactions are related with the feasibility of cis and/or trans attack of the amino acids to the binary chiral chelate retained on the stationary phase.

• Bulletin of the Korean Chemical Society
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• v.13 no.4
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• pp.407-413
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• 1992

The chromatographic separation of the stereoisomers of the N-(3,5-dinitrobenzoyl) derivatives of fifteen dipeptide methyl esters and nine dipeptide alkyl esters was investigated on three different chiral stationary phases derived from N-acylated ${\alpha}-arylalkylamines$. Two of these CSPs contain second stereogenic centers. These secondary stereogenic centers of CSPs were proposed to provide secondary effects in terms of chiral recognition. From the elution orders of the four dipeptide stereoisomers and the separation factors of the enantiomeric pairs of the N-(3,5-dinitrobenzoyl) derivatives of the dipeptide alkyl esters having different alkoxy substituents, it was proposed that the intercalation of the alkoxy substituents of dipeptide derivatives between the connecting arm of CSPs may control the magnitude of chiral separations of dipeptide derivatives.

• Bulletin of the Korean Chemical Society
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• v.22 no.6
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• pp.616-622
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• 2001

Split-flow thin (SPLITT) cell Fractionation(SF) is a technique that allows separation of particulates and macromolecules into two fractions. A gravitational SF(GSF) system is constructed and tested for its applicability for separation of dust and ground water particulates. When tested with polystyrene latex particles, experimental data were in good agreements with theory. The 9.8 and 21.4㎛ polystyrene particles were successuflly separated in a continuous mode, where the mixture is continuously fed into the GSF channel allowing separation in a large sacle. The GSF system is successfully applied to continuous separation of dust and ground water particels based on the sedimentation coefficient, which is closely related to the particle size. The separations were confirmed by microscopy and energy-dispersive X-ray (EDX) analysos.