• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.12
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• pp.2313-2327
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• 1994

As the communication environment evolves, there is an increasing need for multiresolution image coding. To meet this need, the entrophy constratined vector quantizer(ECVQ) for coding of image pyramids by spline wavelet transform is introduced in this paper. This paper proposes a new scheme for image compression taking into account psychovisual feature both in the space and frequency domains : this proposed method involves two steps. First we use spline wavelet transform in order to obtain a set of biorthogonal subclasses of images ; the original image is decomposed at different scale using a pyramidal algorithm architecture. The decomposition is along the vertical and horizontal directions and maintains constant the number of pixels required the image. Second, according to Shannon's rate distortion theory, the wavelet coefficients are vectored quantized using a multi-resolution ECVQ(entropy-constrained vector quantizer) codebook. The simulation results showed that the proposed method could achieve higher quality LENA image improved by about 2.0 dB than that of the ECVQ using other wavelet at 0.5 bpp and, by about 0.5 dB at 1.0 bpp, and reduce the block effect and the edge degradation.

• Archives of Pharmacal Research
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• v.19 no.6
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• pp.480-485
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• 1996

Brain GABA transaminase is inactivated by preincubation with antidepressant/antipanic drug pheneizine (${\beta}$ethylphenylhydrazine) (mixing molar ratio 10:1) at pH 7.4. The reaction of enzyme with phenelzine was monitored by absorption and fluorescence spectroscopic methods. The inactive enzyme was fully reconstituted by addition of cofactor pyridoxal-5-phosphate. This result implies that the blocking of 1 mol of pyridoxal-5-phosphate per enzyme dimer is needed for inactivation of the enzyme. The time course of the reaction is significantly affected by the substrate .alpha.-ketoglutarate, which afforded complete protection against the loss of catalytic activity. The kinetic studies shows that phenelzine reacts with the cofactor of enzyme with a second-order rate constant of $2.1{\times}10^3M^{-1}s^{-1}$. It is postulated that the antidepressant/antipanic drug phenelzine is able to elevate the neurotransmitter GABA levels in central nervous system by inhibitory action on GABA degradative enzyme GABA transaminase.

• Applied Biological Chemistry
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• v.28 no.4
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• pp.271-277
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• 1985

A polarograph with specially designed cell compartment usable in kinetic study of the mitochondrial respiration of a small sized sample was made, and its performance and experimental conditions were examined. An applied potential (ca-1.2V vs. SCE) which gives rise to the second step reduction of oxygen caused a considerable level of a residual current independent of oxygen, which is temporarily interpreted as the reduction current of the membrane-bound redox material(s) of mitochondria. A potential corresponding to the first slop reduction of oxygen (ca-0.4V vs SCE) did not produce the residual current. Thus, it is suggested that a measurement of oxygen concentration in a sample of mitochondria and submitochondrial particles by using dropping mercury electrode should be done with an applied potential of about -0.4V vs SCE. Consumption of oxygen by mitochondria was observed to follow practically zero order kinetics. Its rate constant exhibited the proportional relationship with the respiratory activity of mitochondria. Usefulness of tile instrument was properly demonstrated in the work on the temperature effect on the respiration of mitochondria isolated from several plant 4issues which were selected on the basis of chilling susceptivity.

• Journal of Korean Society on Water Environment
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• v.35 no.2
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• pp.123-130
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• 2019

Ethylenediaminetetraacetic acid-modified bentonite (EMB) was used for adsorption of zinc ion (Zn) from aqueous solution, compared with unmodified bentonite (UB). Parameters such as dose (0.750 ~ 3.125 g/L), mixing intensity (10 ~ 150 rpm), contact time (0.17 ~ 30 min), pH (2 ~ 7), and temperature (298 ~ 338 K), were studied. Zn removal efficiency for EMB was 20 ~ 30 % higher, than that for UB, in all experiments. Thermodynamic studies demonstrated that adsorption process was spontaneous with Gibb's free energy (${\Delta}G$) values, ranging between -5.211 and -7.175 kJ/mol for EMB, and -0.984 and -2.059 kJ/mol for UB, and endothermic with enthalpy (${\Delta}H$) value of 9.418 kJ/mol for EMB and 7.022 kJ/mol for UB. Adsorption kinetics was found to follow the pseudo-second order kinetics model, and its rate constant was 3.41 for EMB and $2.00g/mg{\cdot}min$ for UB. Adsorption equilibrium data for EMB were best represented by the Langmuir adsorption isotherm, and calculated maximum adsorption capacity was 2.768 mg/g. It was found that the best conditions for Zn removal of EMB within the range of operation used, were 3.125 g/L dose, 90 rpm intensity, 10 min contact time, pH 4, and 338 K. Therefore, EMB has good potential for adsorption of Zn.

• Applied Chemistry for Engineering
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• v.22 no.2
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• pp.224-229
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• 2011

Adsorption characteristics of erythrosine dye onto the activated carbon has been investigated in a batch system with respect to initial concentration, contact time and temperature. Kinetic studies of the adsorption of erythrosine were carried out at 298 K, using aqueous solutions with 100, 250 and 500 mg/L concentration of erythrosine. The adsorption process followed a pseuo second order model, and the adsorption rate constant (k2) decreased with increasing the initial concentration of erythrosine. The equilibrium process can be well discribed by Freundlich isotherm in the temperature range from 298 to 318 K. Free energy of adsorption (${\Delta}G^o$), enthalpy (${\Delta}H^o$), and entropy (${\Delta}S^o$) change were calculated to predict the nature the adsorption. The estimated values for ${\Delta}G^o$ were -3.72~-9.62 kJ/mol over the activated carbon at 250 mg/L, indicated toward a spontaneous process. The positve value for ${\Delta}H^o$ indicates that the adsorption of erythrosine dye on activated carbon is an endothermic process.

• Bulletin of the Korean Chemical Society
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• v.6 no.5
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• pp.287-291
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• 1985

The addition of poly(styrenesulfonate) (PSS) to $Ru(bpy)_3^{2+}$ solutions shifted the emission peak by 3 nm to red, and increased emission intensity by 1.8 times. By contrast, poly(vinylsulfonate) (PVS) had little effect on the fluorescence spectrum. The effects of PSS on the spectral properties of $Ru(bpy)_3^{2+}$, were attributed to the presence of a hydrophobic phenyl group in PSS, which interact with $Ru(bpy)_3^{2+}$ by, at least in part, hydrophobic effect. The binding constant of $Ru(bpy)_3^{2+}$ to PSS in 0.1 M NaCl was $6{\times}10^4\;M^{-1}$, and this value was about $10^3$ times higher than those of methyl viologen ($MV^{2+}$) and $Cu^{2+}$. The Stern-Volmer constants of emission quenching of $Ru(bpy)_3^{2+}$ by $MV^{2+}$ and $Cu^{2+}$ in 0.1 M NaCl solutions were 426 and 40 $M^{-1}$, which correspond to second order rate constants($k_q$) of $1.1{\times}10^9\;and\; 1.0{\times}10^8\;M^{-1}s^{-1}$, respectively. The presence of PSS enhanced $K_{SV's}\;by\;{\sim}50$ times, whereas PVS increased the values only 1-4 times. The large enhancing effect of PSS, despite of lower charge density than PVS, was explained in terms of longer life-time of photoexcited $Ru(bpy)_3^{2+}$ bound to PSS and strong association of $Ru(bpy)_3^{2+}$ to PSS due to a specific interaction involving hydrophobic effect. The variation of $K_{SV's}$ on the concentrations of PVS and PSS were also investigated for $Ru(bpy)_3^{2+}-MV^{2+}\;and \;Ru(bpy)_3^{2+}-Cu^{2+}$ photoredox systems.

• Polymer(Korea)
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• v.25 no.1
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• pp.6-14
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• 2001

The monomer N,N'-bis(3-pyrrol-1-yl-propyl)-4,4'-bipyridinium$(PF_6)_2$ was electrochemically polymerized on glassy carbon electrode surface. This polymer film electrode has electroactive sites on its bipyridinium ions distributed at the polymer strands. The formal potentials of the electrodes were -0.41V and -0.81V(vs. SSCE) for each step at phosphate buffer(pH=5.70). The diffusion coefficients of the dopants ions into the polymer matrix were $1.57{\times}10^{-4}$ and $4.35{\times}10^{-5}cm^2s^{-1}$ for first and second redox couple, respectively. The rate constants of electron transfer at $V^{2+/+}$ of the first step was a $57.53s^{-1}$, which was 22 times higher than $V^{+/0}$ one having $2.63s^{-1}$ in the solution. The charge transfer resistance of the polymer film was influenced by the dopant ion of the electrolyte. Thus the resistances were 22.63, 16.81, 12.44 and $11.36k{\Omega}$ for $LiClO_4,\;NaClO_4,\;KClO_4$, and phosphate buffer, respectively. The reaction order of the electropolymerization was first order and the rate constant of the polymerization was $1.31{\times}10^{-1}s^{-1}$ as determined by EQCM method. The G.C./p-BPB type electrode doped with phosphate ions showed a stability and reproducibility in CV procedure over 20 cycles.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.23 no.4
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• pp.151-156
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• 1987

The author carried out an experiment to find out the response of sea-bass, Epinephelus septemfasciatus (Thunberg) to the color lights. The experimental tank (360L$\times$50W$\times$55H cm) was set up in a dark room. Six longitudinal sections with 60 cm intervals are marked in the tank to observe the location of the fish. Water depth in the tank was kept 50 cm level. Light bulbs of 20 W at the both ends of the tank projected the light horizontally into the tank. Two different colored filters were selected from four colors of red, blue, yellow, and white, and they were placed in front of the light bulbs to make different colors of light. Light intensity were controlled by use of auxiliary filters intercepted between the bulb and the filter. The fishes were acclimatized in the dark for 50 minutes before they were employed in the experiment. Upon turning on the light, the number of fish in each section was counted 40 times in 30 second intervals, and the mean of the number of fish in each section was given as the gathering rate of the fish. The colors favourited by the fish was found in the order of blue, red, white and yellow in day time, and red, blue, yellow and white at night time. The gathering rate of fish on illumination period was not constant and fluctuated with irregularity. The difference of the gathering rate on two different colors of light was small and the difference was larger in night time then in day time.

• KSBB Journal
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• v.19 no.3
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• pp.215-220
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• 2004

A variety of solid bases such as inorganic bases, basic anion exchange resins, and resin-bound bases were tested as a catalyst for racemization of (S)-naproxen 2,2,2-trifluoroethyl thioester in isooctane at 45$^{\circ}C$. Among the various bases, DIAIOM WA30, which is a weakly basic anion exchange resin with a tertiary amine based on a highly porous type styrene-divinylbenzene copolymer, showed the highest catalytic activity. The second-order interconversion constant of DIAION WA30 was 8.6${\times}$10$\^$-4/ mM$\^$-1/h$\^$-1/ and about 3 times higher than that of trioctylamine under the same conditions. The rate of DIAION WA30-catalyzed racemization decreased with increasing an amount of water added to the reaction medium. Lipase-catalyzed kinetic resolution of racemic naproxen 2,2,2-trifluoroethyl thioester was successfully carried out under in situ racemization of substrate with DIAION WA30 in isooctane at 45$^{\circ}C$. More than 60% conversion and 99% enantiomeric excess for the desired (S)-naproxen product were obtained. Furthermore, such a solid base catalyst could be easily separated and reused in contrast to trioctylamine.

• Clean Technology
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• v.26 no.1
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• pp.30-38
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• 2020

The kinetic and thermodynamic parameters of Acid Red 66, adsorbed by granular activated carbon, were investigated on areas of initial concentration, contact time, and temperature. The adsorption equilibrium data were applied to Langmuir, Freundlich, Temkin, Redlich-Peterson, and Temkin isotherms. The agreement was found to be the highest in the Freundlich model. From the determined Freundlich separation factor (1/n = 0.125 ~ 0.232), the adsorption of Acid Red 66 by granular activated carbon could be employed as an effective treatment method. Temkin's constant related to adsorption heat (B_T = 2.147 ~ 2.562 J mol^-1) showed that this process was physical adsorption. From kinetic experiments, the adsorption process followed the pseudo-second order model with good agreement. The results of the intraparticle diffusion equation showed that the inclination of the second straight line representing the intraparticle diffusion was smaller than that of the first straight line representing the boundary layer diffusion. Therefore, it was confirmed that intraparticle diffusion was the rate-controlling step. From thermodynamic experiments, the activation energy was determined as 35.23 kJ mol^-1, indicating that the adsorption of Acid Red 66 was physical adsorption. The negative Gibbs free energy change (ΔG = -0.548 ~ -7.802 kJ mol^-1) and the positive enthalpy change (ΔH = +109.112 kJ mol^-1) indicated the spontaneous and endothermic nature of the adsorption process, respectively. The isosteric heat of adsorption increased with the increase of surface loading, indicating lateral interactions between the adsorbed dye molecules.