• Applied Chemistry for Engineering
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• v.21 no.5
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• pp.505-508
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• 2010

The characteristics of desorption reaction for spent activated carbon produced from the manufacture of other chemical products in Shiwha/Banwal industrial complex were investigated. TGA (Thermogravimetric Analyzer) was used to study for characteristics of desorption and kinetics. Then Friedman method and Freeman-carroll method were used to find the activation energy and the order of reaction. Activation energy by Friedman method was 24.82~46.49 kJ/moL. And then activation energy and order of reaction by Freeman-carroll method were 8.77~32.26 kJ/moL and 0.11~1.69.

• Transactions of the Korean hydrogen and new energy society
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• v.19 no.4
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• pp.305-312
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• 2008

ZnO/Zn redox cycle is the one of the promising thermochemical cycles for hydrogen production via water splitting with high temperature heat source like a concentrated solar energy. This paper reports the particle size effect of Zinc on water splitting behavior. Water splitting reaction experiments were carried out at isothermal conditions of 350 and 400$^{\circ}C$ in TGA (Thermo Gravimetric Analyzer) using four commercial Zinc powders (nano, <10 ${\mu}m$, <150 ${\mu}m$ and $150{\sim}600\;{\mu}m$ particle sizes). Before the experiments, average particle size of Zinc powders was analyzed by PSA (Particle Size Analysis). After the experiments, XRD (X-Ray Diffraction) and SEM (Scanning Electron Microscope) analyses were conducted on the samples. The experimental results showed that particle size had a effect on the conversion of Zinc to ZnO. Zinc conversion was increased, as the particle size decreased. Especially, the nano size particles were aggregated and the particle's morphology changed on the surface during hydrolysis reaction.

• Journal of the Korean Chemical Society
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• v.44 no.6
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• pp.592-599
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• 2000

The fine particles of binary ceramic composite of titania-partially-stabilized zirconia(TPSZ) were synthesized by ultrasonic spray pyrolysis at the various temperatures, compositions and concentrations and the effects of process factors for synthesis on the characteristics of fine particles were discussed. The starting salt solutions were prepared to have the ionic concentrations of 0.025~0.1 M aqueous solutions. The fine particles were prepared to have the compositions of 90~97.5 wt% of $ZrO_2$ and 2.5~10 wt% of $TiO_2$. The temperatures for particle synthesis were regulated to be 400~550$^{\circ}C$ as a drying zone, 800~1100$^{\circ}C$ as a pyrolysis zone. The produced fine particles were collected by a wet process and analyzed to investigate characteristic properties after being dried. The compositions of ceramic fine particles were determined by Inductively Coupled Plasma-Atomic Emission Spectroscopy(ICP-AES) technique and phases, morphologies and particle sizes of those were investigated by Raman Spectroscopy, X-ray diffraction(XRD), Scanning Electron Microscopy(SEM), Transmission Electron Microscopy(TEM) and Particle Size Analyzer(PSA) techniques.

• Journal of the Korean Electrochemical Society
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• v.7 no.1
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• pp.16-20
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• 2004

To electropolymerize Polypyrrole(ppy) film modified with fullerene $ions(full^-)$ the cell, Au/5 mM pyrrole, 1mM fullerene, 0.1M $TBABF_4,\;CH_2Cl_2/Pt$, was employed to Prepare the wafer-like type of $electrode/ppy(full^-)ppy(full^-){\ldots}$ electrodes. They were applied to deposit alkali metal ions with the cell of Au(quartz crystal analyzer; QCA)/ppy$(full^-)$, 0.01M metal ion(aq.)/Pt. The depositing rate constant of each ion for $Li^+,\;Na^+,\;K^+,\;Rb^+\;and\;Cs^+$, determined from the first order equation was $1.60\times10^{-8},\;3.13\times10^{-11},\;1.38\times10^{-9},\;2.71\times10^{-11}\;and\;2.98\times10^{-12}mo1.s^{-1}$ respectively. The calculated stoichiometry of the ions determined by quartz crystal microbalance(QCM) at the electrodes was $Li_7C_{60},\;Na_4C_{60},\;K_3C_{60},\;Rb_1C_{60}\;and\;Cs_1C_{60}$ respectively.

• Polymer(Korea)
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• v.35 no.6
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• pp.548-552
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• 2011

Two functionalization methods, i.e., acid treatment and chemical amidation were performed to prepare the functionalized multi-walled carbon nanotubes (MWCNT), and the properties of epoxy/functionalized MWCNT composites were investigated and compared. Fourier transform infrared spectroscopy (FTIR) was used to confirm the surface functionality of the MWCNT obtained by the functionalization methods. The effects of the MWCNT functionalization on the interface and thermal conductivity were studied by zeta potential analyzer, scanning electron microscope and thermal conductivity analyzer. From these results, it was confirmed that the thermal conductivity of the epoxy/MWCNT composites could be increased by grafting with dodecylamine. This could be interpreted by relatively strong dispersion forces of the grafting MWCNT with dodecylamine in DGEBF epoxy resin. These results were in good agreement with the results that the zeta potential value of the grafting MWCNT with dodecylamine has a higher negative value than that of MWCNT with acid treatment.

• Journal of Adhesion and Interface
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• v.8 no.2
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• pp.9-14
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• 2007

Poly(ethylene glycol) (PEG), isophoron diisocyanate (IPDI), and 1,1,1-tris(hydroxymethyl)propane (THMP) were used to synthesize polyurethane microgel. The formulation to form a microgel was determined, and the shape and the properties of the microgel were characterized with SEM and particle size analyzer. The microgel was only formed when PEG was used more than THMP exceedingly. Therefore, it is believed that PEG plays an important role in the synthesis of the microgel. During the formation of the microgel, the viscosity of the microgel solution was decreased. Molecular weights of the PEGs which were used in this research were 2,000, 6,000, and 10,000. The microgel synthesized with PEG 6000 showed the best property in comparison with others. The size of the microgel measured by particle size analyzer were about 130~230 nm.

• Journal of Veterinary Science
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• v.23 no.4
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• pp.60.1-60.6
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• 2022

Background: A definite diagnosis should be made in the bovine practice field, however, it was difficult to perform laboratory analysis immediately. Currently, three types of portable blood gas analyzers are available in Korea. Objectives: This study aimed to evaluate the correlations among these three analyzers. Methods: Seventy-two plasma samples from Holstein-Friesian cows were used for blood gas analysis, and three instruments (EDAN i15 Vet, VETSCAN i-STAT, and EPOC) were operated simultaneously. Moreover, plasma calcium levels were compared between these portable analyzers and blood chemistry device, which is usually used in a laboratory environment. Pearson analysis was performed to confirm the correlation of each parameter produced with the three instruments and blood chemistry analyzer. Results: As results, high correlation was observed in parameters of pH, pO₂, potassium ion, ionized calcium, and glucose (p < 0.001, r > 0.7). In addition, pCO₂ showed a moderate correlation among the three analyzers (p < 0.001, r > 0.5), and there was no correlation among all instruments for sodium ions. There was also a high correlation between ionized calcium from the three portable devices and total calcium from the biochemistry analyzer (p < 0.001, r > 0.9). Conclusions: In conclusion, there was a high correlation between results from the three different blood gas analyzers used in the bovine clinical field in Korea. Thus, a consistent diagnosis can be made even with different equipment if the operator is aware of the strengths and weaknesses of each piece of equipment and operates it properly.

• Journal of the Korean Chemical Society
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• v.60 no.5
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• pp.299-309
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• 2016

In this study, the physicochemical and electrochemical properties of carbon nanomaterials and synthesized nano-carbon/Si composites were studied. The nano-carbon/Si composites were ball-milled to a nano size and coated with pyrolytic carbon using Chemical Vapor Deposition (CVD). They were then finely mixed with respective nano-carbon materials. The physicochemical properties of samples were analyzed using Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS), Raman spectroscopy, X-ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), and surface area analyzer. The electrochemical characteristics were investigated using the galvanostatic charge-discharge and cyclic voltammetry (CV) measurements. Three-electrode cells were fabricated using the carbon nanomaterials and nano-carbon/Si composites as anode materials and LiPF₆ and LiClO₄ as electrolytes of Li secondary batteries. Reversibility using LiClO₄ as an electrolyte was superior to that of LiPF₆ as the electrolyte. The initial discharge capacities of nano-carbon/Si composites were increased compared to the initial discharge capacities of nano-carbon materials.

• Archives of Pharmacal Research
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• v.2 no.2
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• pp.133-144
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• 1979

To investigate constituents of Strobilomyces floccopus (Fr.) Karst. and Coprinus comatus (Fr.) S. F. Gray, free and total amino acids of the two mushrooms were quantitatively analyzed by G. L. C. and an amino acid analyzer. Free amino acids were extracted from both mushrooms with ethanol. Fourtenn free amino acids were detected from the ethanol extract of S. floccopus and fifteen free amino acids from C. comatus by G. L. C. And the dry carphopores of both mushrooms were hydrolyzed with hydrochloric acid and then the total protein amino acids were analyzed by A. A. A. Seventeen total amino acids were detected from each acid-hydrolysate of S. floccopus and C. comatus. Lipids were extracted from the carpophores of S. floccopus and saponified with alcoholic potassium hydroxide. The isolated sterols were subjected to G. L. C. and two sterols were detected. The isolated free fatty acids were methylated with diazomethane and subjected to column chromatography and G. L. C. Eleven saturated and nine unsaturated free fatty acids were detected from the carpophores of S. floccopus. The presence of these nutrient components shows that the two mushrooms can be utilized as edible ones.

• Applied Chemistry for Engineering
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• v.10 no.3
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• pp.382-387
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• 1999

The processes and the kinetics of the lithium intercalation into the spin coated $V_2O_5$ xerogel prepared by the sol-gel processing have been studied employing impedance analyzer. Homogeneous and quasi-isotropic thin films of the xerogel can be obtained as a result of random distribution of the $V_2O_5$ gels on the substrate by the use of the spin coating. Effective diffusion coefficient and charge transfer resistance vary more than one order of magnitude at high and low lithium composition in $V_2O_5$ xerogel, respectively.