• Proceedings of the KIEE Conference
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• 1997.07d
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• pp.1436-1438
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• 1997

In this paper, CdS thin films, which were widely used window layer of the CdS/CdTe and the CdS/$CuInSe_2$ heterojunction solar cell, were grown by chemical bath deposition, and The properties were investigated in detail. Cadmium acetate and thiourea were used as cadmium and sulfur source, respectively. And Ammonium acetate was used as the buffer solution. Also Ammonia was used for controlling pH concentration. The reaction velocity was increased with increasing reaction temperature and decreasing pH concentration. The crystal structure of CdS films grown with various pH concentration had the hexagonal structure with (002) plane peak. In the range of pH $9{\sim}9.5$, the intensity of the peak was highest, and as increasing pH concentration, decreased the intensity of the peak except pH12.

• Journal of Ginseng Research
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• v.9 no.2
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• pp.154-162
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• 1985

We report a newassay method on the measurement of the catalase activity, whose utilzation value is considered to be remarkable in the field of plant biochemistry. We named this method as a De-Coupling method. The essence of de-coupling method is the separation between the enzyme reaction and the indicator reaction. The optimum condition of the enzyme reaction was found to be following: on addition of 1 ml of substrate (H2O2: 20mM) to the fixture of the crude extract of enzyme (volume: 0.2 ml) and the ammonium phosphate buffer (volume: 1.8 ml; 0.93 M phosphate, 1.6M NHB, 2.5 M methanol, pH 7.0). After 30, 60 and 90 seconds of the enzyme reactions are proceeded, the reactions are terminated by 25% of tai-chloro-acetate (final concentration of 5%), respectively. The precipitated materials by tai-chloro-acetate was removed by the centrifugation (2000g, 10minutes). Formaldehyde produced in the enzymatic reaction was reacted with 2ml of acetylacetone (60mM). The indicator reaction -(HANTSCH REAKT10N)- in which lutidine is formed, was proceeded for 60 minutes at $25^{\circ}C$.

• Journal of Oral Medicine and Pain
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• v.8 no.1
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• pp.33-41
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• 1983

The authors observed the ultrastructure of oral leukoplakia simplex of gingiva, buccal mucosa, tongue and alveolar ridge. For the purpose of clearly defining the lesions under investigation in this study, leukoplakias were cinsidered to be any white patches on the oral mucous membranes that could not be removed by rubbing and could not be classified clinically or microscopically as another diagnosable disease. The tissue to be examined were embedded in paraffin for light microscopic study. The tissue to be examined under the electronomicroscope were fixed in 2.5% glutaraldehyde in 0.1M cacodylate buffer and 1% osmic acid in 0.1M cacodylate buffer, dehydrated with guaded alchol, and treated with propylene oxide, and embedded in Epon.Ultrathin sections were obtained by LKB III ultrotome, stained with uranyl acetate/lead citrate, and examined with Corinth 500EM. The results were as follows : 1. Epithelium of leukoplakia consisted of stratum basale, stratum spinosum, stratum granulosum and stratum corneum. 2. There was hyperorthokerotosis or hyperparakeratosis. 3. Granular cells contained a lot number of membrane coating granule showing lamellar structure, clearing ot codensation, and a lot of keratohyaline granule varied in size. 4. An increased concentration of tonofilaments and an increased number of desmosomes were found in the stratum spinosum. 5. Basal lamina generally showed its continuity, but in some locatoins, its interreption and multiplication appeared.

• Journal of Environmental Health Sciences
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• v.29 no.2
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• pp.62-68
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• 2003

Differential pulse voltammetry (DPV) using nafion-coated glassy carbon electrodes modified with Tetren(tetraethylene pentamine)-glycerol showed sensitivity for determining lead (II) at low concentration. The Lead (II) was accumulated on the electrode surface by the formation of the complex in an open circuit, and the resulting surface was characterized by medium exchange, electrochemical reduction, and differential pulse voltammetry. Various experimental parameters, such as the composition of modifier, preconcentration time, pH of electrolyte (0.1 M acetate buffer), and parameters of differential pulse voltammetry, were optimized. The initial potential was applied for 50 s, the electrode was scanned from -0.9 to -0.3 V, and the anodic peak current was measured at -0.604 V $\pm$ 0.015 V (vs. Ag/AgCl). The calibration plot was obtained in the range 1.0$\times$10$^{-8}$ M~l.0$\times$10$^{-6}$ M with pH 4.5 buffer solution. The detection limit (3$\sigma$) it as low as 5.0$\times$ 10$^{-9}$ M. This method is applied to the determination of lead(II) in a certified reference material and the result agrees satisfactorily with the certified value.

• Journal of the Korean Chemical Society
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• v.7 no.1
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• pp.29-33
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• 1963

A new method determining the micro amount of cupferron spectrophotometrically was investigated and was considered on the various factors which affect on the method. The method was as follows; ferric alum solution was added in a suitably acidified solution of cupferron. After the precipitates of Fe(Ⅲ)-cupferrate were formed, they were extracted with chloroform and the absorbancy of the organic phase was measured by spectrophotometer, Beckmann Model B (1cm quartz cell). The stable maximum wavelength was 325 $m{\mu}$ at 3.0 to 5.6 of the optimum pH and it obeyed on Boer's law in the range of 5.76 ${\gamma}/ml$ to 74.80 ${\gamma}/ml$ of cupferron. The maximum wavelength was independent on pH, concentration of cupferron and of ferric alum. The absorbancy at 325 $m{\mu}$ was not affected by $SO_4^{--}$ and Ac, but was varied by $Cl^-$ and $NO_3^-$. Sulfuric acid and acetate buffer are preferred to the acid and buffer solution adjusting the pH. At higher acidity, however, the absorbancy was somewhat lowered because of the decomposition of cupferron, and at too high concentration of ferric alum, it was also decreased because of the difficulty in the extraction. By this method, it was able to determine cupferron quantitatively in the percent error of 1.18.

• KSBB Journal
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• v.8 no.1
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• pp.83-88
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• 1993

Lipase was separated using reverse mlcelles in a spray column. The 50 mM AOT-Isooctane solution was used as reverse micellar solution for the extraction of lipase (crude containing 25% Protein). Ionic strength was controlled by KCl(0.1M KCl for extraction, 0.5M KCl for back exlractlon). Acetate buffer and phosphate buffer were used for control of pH. The efficiencies of extraction and stripping were 30% and 50%. An increase of circulation did not change the efficiency of extraction in forward extraction. The optimum flow rate was around 0.10ml/sec.

• Journal of Nutrition and Health
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• v.28 no.2
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• pp.115-126
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• 1995

The effects of energy-yielding substrates on coronary circulation, myocardial oxygen metabolism, and intramyocytic adenylates of perfused Wistar control rat(WC) and spontaneously hypertensive rat(SHR) hearts were examined under basal and $\beta$-adrenergic stimulation conditions. The perfusion medium (1.0mM Ca2+) contained 5mM glucose (+5U/l insulin) in combination with 5mM pyruvate, 5mM lacate, 5mM acetate, or 5mM octanoate as energy substrates. Hearts were perfused with each substrate buffer for 20min under basal conditions. Coronary functinal hyperemia was induced by infusing for 20min isoproterenol (ISO, 1uM), a $\beta$-receptor agonist. Cardiac adenylates, glycolytic intermediates, and coronary venous lactate were measured by using an enzymatic analysis technique. Under basal conditions, acetate and octanoate significantly increased coronary flow(CF) of WC in parallel with myocardial oxygen consumption. However, CF of SHR was partly attenuated by coronary vasoconstriction despite metabolic acidosis. In addition, pyruvate and lactate depressd ISO-induced coronary functional hyperemia in SHR. It should be noted that octanoate exhibited coronary dysfunction under ISO conditions. On the other hand, fat substrates depleted myocardial high energy phosphate pool and accumulated breakdown intermediates. In SHR with coronary vasoconstriction under basal conditions, and with depressed coronary functional hyperemia, high energy phosphates were greatly depleted. These results suggest that energy substrates in the myocardium and coronary smooth muscle alter remarkably coronary circulation, and that coronary circulatory function is associated with a reserve of high energy phosphates and a balance between breakdown and nono synthesis of energy phosphates. These findings could be explained by alterations in the cytosolic redox state manipulated by LDH and hence in the cytosolic phosphorylation potential, which might be involved in hypertension of SHR.

• Korean Journal of Agricultural Science
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• v.19 no.1
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• pp.103-114
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• 1992

Screening for antioxidative activities of 180 species of crude drugs were performed on their methanol extracts. More than 45% of those showed some effect on oxidative stability of linoleic acid, and 44 species seemed to have rather strong antioxidative activity. Selected these samples of the active crude drugs were further examined in their methanol extracts with methyl linoleate emulsion system. especially 11 species revealed strong antioxidative activity. These 11 species were then successively extracted with ethyl acetate and petroleum ether, and their antioxidative activity was determined. The ethyl acetate and petroleum ether extracts of Epimedium Koreanum NAKAI, Psoralea Corylifolia L., Syringa Dilata NAKAI and Prunus mume Sieb, et Zucc. showed much more effective than the others in stabilizing methyl linoleate. Scutellaria baicalensis George. Glycyrrhiza glabra L. were only effective in the methanol extract.

• Journal of Hydrogen and New Energy
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• v.19 no.6
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• pp.498-504
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• 2008

Metal-reducing bacterium, Geobacter sulfurreducens is available for mediator-less microbial fuel cell (MFC) because it has biological nanowires(pili) which transfer electrons to outside the cell. In this study, in the anode chamber of the MFC system using G. sulfurreducens, the concentrations of NaCl, sodium phosphate and sodium bicarbonate as electrolytes were mainly optimized for the generation of electricity from acetate. 0.4%(w/v) NaClO and 0.5M $H_2SO_4$ could be utilized for the sterilization of acrylic plates and proton exchange membrane (major construction materials of the MFC reactor), respectively. When NaCl concentration in anode phosphate buffer increased from 5 to 50 mM, power density increased from 6 to $20\;mW/m^2$. However, with increasing sodium phosphate buffer concentration from 5 to 50 mM, power density significantly decreased from 18 to $1\;mW/m^2$. Twenty-four mM sodium bicarbonate did not affect electricity generation as well as pH under 50 mM phosphate buffer condition. Optimized anode chamber of MFC using G. sulfurreducens generated relatively high power density ($20\;mW/m^2$) with the maximum coulombic efficiency (41.3%).

• The Korean Journal of Zoology
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• v.15 no.3
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• pp.133-147
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• 1972

Ultrastructures of spermiogeneis in other invertebrates were investigated by several workes (Anderson, et al., 1967; Bloch, et al., 1964; Christen, 1961; Gatenby, et al., 1959; Paik, et al., 1968; Silveira, 1964; Yasuzumi, 1957) but spermiogenesis of dragonfly has not been reported previously. Testes and vass deferentia of the Korean dragonfly, Crocothemis servilia, were used for electron microscopic study of spermiogenesis. Materials were prefixed for 1-2 hours at $3^{\circ}C$ in 1.25% glutaraldehyde buffered to pH 7.2 with 0.2M sodium cacodylate buffer. Fixed tissue was washed twice in 0.2M cacodylate buffer and was subsequently postfixed for 2 hours at $3^{\circ}C$ in 1% osmium tetroxide buffered to pH 7.2 with 0.4M sodium cacodylate buffer solution. Specimens were dehydrated in graded ethyl alcohol, and finally embedded in epoxy Epon resin. Thin sections prepared from all the blocks were doubly stained; first in uranyl acetate and then in lead citrate. All thin sectios were examined with a Hitachi HS-7S electron microscope. The results of this study were summarized as follows. 1. Along the condensation of chromatin in nucleus, the shpae of nucleus was changed from spherical shpae to ellipse and cone cell type. 2. During the elongation of nucleus and the migration of cytoplasm, the nucleus removed to the one side of spermatid and began to invaginate from the posterior portion of nucleus. 3. There are ring centrioles in invaginated portion and axial filaments derived from centriole extend to the tail through the tailward half of spermatid. 4. In the cross sections the axial filament consisted of a central sheath, a central fibril, and 9 peripheral doublets.