• Toxicological Research
• /
• v.9 no.1
• /
• pp.45-60
• /
• 1993

The present study was carried out to evaluate the cytotoxicity of cadmium on cultured rat fibroblasts. The colorimetric assays of neutral red and tetrazolium MTT, the lactatedehydrogenase activity, the amounts of total protein, the rate of DNA synthesis, the amounts of unscheduled DNA synthesis, the frequency of sister chromatid exchange, the releasing rate of intracellular calcium, and light and electron microscopic studies were performed on cultured rat fibroblasts maintained in the media containing various concentrations of cadmium. The results were as follows: The neutral red(NR) and MTT values were decreased dose-dependently by cadmium, and the NR90, NR50, MTT90 and MTT50 values of cadmium were 0.2mM, 21.5mM, 1.0Mm and 60.0Mm, respectively.

• Korean Journal of Metals and Materials
• /
• v.48 no.2
• /
• pp.141-147
• /
• 2010

An Ni-Al intermetallic coating has been produced by induction heating on mild steel. The effect of the induction heating conditions on the microstructure of the coating has been investigated. The reaction synthesis of the intermetallic compounds was promoted while increasing the heating rate and the holding time at reaction temperature. Especially, an NiAl phase corresponding to the initial composition of mixed powder was predominantly formed. However, the synthesis at low reaction temperatures occurred by solid state diffusion during the holding time and an Fe-Al reaction layer was formed at the interface with the substrate, regardless of the heating rate. The combustion synthesis of the intermetallic compound occurred at a temperature higher than 1023 K and resulted in an almost single phase NiAl structure.

• Proceedings of the IEEK Conference
• /
• 1999.11a
• /
• pp.1127-1130
• /
• 1999

In this paper, using one method of Additive Synthesis, Analysis-by-synthesis/Overlap-Add (ABS/OLA) method, analysis and synthesis of musical tones is processed. But peak detection of frequency domain is processed by proposed method considering the view of acoustics. It is that that harmonics frequency is times of main frequency. Using this fact, peak detection of frequency domain is useful for detection of tonal component identified musical note. It is possible to realize high-quality lour bit rate audio.

• Development and Reproduction
• /
• v.20 no.2
• /
• pp.127-133
• /
• 2016

Purine metabolism is known factor for nuclear maturation of oocytes through both follicle cells and oocyte itself. However, it is largely unknown the roles of purine metabolism in the oocyte competence for fertilization and early development. In this study, the effects of adenosine in oocyte competence for development were examined using adenosine and its synthetic inhibitors. Adenosine treatment from GV intact stage for 18 hr (fGV) caused of decrease the fertilization rate but of increase the cleavage rate compared from the other stage treatment groups. Hadacidin did not effect on fertilization rate but increased cleavage rate without stage specificity. Adenosine did not block the effects of hadacidin with the exception of fGV group. Inhibition of purine synthetic pathways the fertilization rate was decreased in the fGV and fGVB groups but increased in the fMII group. Exogenous adenosine caused of decrease fertilization rate in the fGVB group but increase in the fMII group. Cleavage rate was dramatically increased in the adenosine treatment with synthetic inhibitors. It means that the metabolism of purine has stage specific effects on fertilization and cleavage. Exogenous adenosine had only can improve oocyte developmental competence when it treated at GV intact stage. On the other hand, endogenous synthesis in all maturation stage cause of increase the cleavage rate without effects on fertilization. These data suggest that adenosine at GV stage as a paracrine fashion and inhibitions of endogenous adenosine in all stage improve oocyte developmental competence.

• Journal of the Korean Ceramic Society
• /
• v.39 no.4
• /
• pp.327-335
• /
• 2002

Experiments were conducted to investigate the synthesis characteristics of Precipitated Calcium Carbonate(for short PCC) in Ca(OH)$_2-CO_2-H_2O$ system by the continuous drop method of Ca(OH)$_2$ slurry into the solution containing $CO_2$(aq). When the flow rate of $CO_2$(g) increases and the concentration of Ca(OH)$_2$ slurry become low, the absorption rate of $CO_2$(g) become faster than the dissolution rate of Ca(OH)$_2$. Consequently, the growth of the calcite crystal plane is facilitated resulting in synthesis of $1.0{\mu}m$ of rhombohedral calcite. On the other hand, when the flow rate of $CO_2$(g) decreases and the concentration of Ca(OH)$_2-CO_2-H_2O$ slurry become high, new nuclei is created along with the crystal growth resulting in synthesis of $0.1{\mu}m$ of prismatic calcite. Maintaining 1.0wt% of Ca(OH)$_2-CO_2-H_2O$ slurry, 120 drops/min of drop rate and $25^{circ}C$ of temperature, the shape of PCC shows colloidal and spherical agglomerate at 100 mL/min of the flow rate of $CO_2$(g); the mixture of rhombohedral and plate-shaped calcite, at 200∼500 mL/min. Therefore, as the flow rate of $CO_2$(g) increases, the shape of PCC changes from colloidal and rhombohedral calcite to plate-shaped calcite. Maintaining 500 mL/min of the flow rate of $CO_2$(g), 120 drops/min of the drop rate of Ca(OH)$_2$ slurry, and $25^{circ}C$ of temperature, the shape of PCC shows the plate-shaped calcite at 1.0∼3.0 wt% of Ca(OH)$_2$ slurry; the hexagonal plate-shape calcite of the thickness of $0.1{\mu}m$ and the width of $1.0{\mu}m$, at 4.0 wt%.

• Journal of the Korean Society of Safety
• /
• v.27 no.5
• /
• pp.77-87
• /
• 2012

Compared to a batch reactor, where all reactants are initially charged to the reactor, the semi-batch reactor presents serious advantages. The feed of at least one of the reactants provides an additional way of controlling the reaction course, which represents a safety factor and increases the constancy of the product quality. The aim of this study was to investigate the characteristics of thermal hazard such as a feed time, catalysis concentration and solvent concentration in methylthioisocyanate(MTI) synthesis reaction process. The experiments were carried out by the Multimax reactor system and Accelerating rate calorimeter(ARC). The MTI synthesis reaction process has many reaction factors and complicated reaction mechanism of multiphase reaction. Through this study, we can use as a tool for assessment of thermal hazard of other reaction processes by applying experiment method provided.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.16 no.1 s.92
• /
• pp.19-25
• /
• 2005

This paper describes a synthesis method for a self-equalized dual-passband filter. Compared to conventional dual-passband filter, a self-equalized dual-passband filter can reduce BER(bit error rate) in digital data communications and does not need an external equalizer for group-delay equalization. To validate the synthesis technique, a 10-pole dual-mode dual-passband filter which has two self-equalized 5-pole elliptic response passband is synthesized.

• Journal of Electrochemical Science and Technology
• /
• v.3 no.2
• /
• pp.80-84
• /
• 2012

The polyaniline (PANI) electrodes are prepared by chemical synthesis and electrodeposition methods and their supercapacitive properties are characterized and compared by morphology observation, cyclic voltammetry as a function of scan rate, and impedance spectra analysis. In particular, the supercapacitive properties obtained in the range of higher potential scan rates (e.g., over $200mV\;s^{-1}$) are emphasized to be capable of utilizing adequately the high power capability of supercapacitor. As a result, the PANI electrode by the electrodeposition shows superior specific capacitance (max. $474F\;g^{-1}$ at $10mV\;s^{-1}$ and about $390F\;g^{-1}$ at $500mV\;s^{-1}$) than those by the chemical synthesis method. This is mainly due to highly porous structure obtained by the electrodeposition to yield higher specific surface area.

• The Journal of the Acoustical Society of Korea
• /
• v.31 no.7
• /
• pp.472-479
• /
• 2012

This paper is aimed to design 9.2 kbps low bits late transform excitation coder that target to voice and audio signal. To set up low bit rate, we used Band-selection in frequency domain and gain-shape quantization and AbS structure. To decrease lots of calculation from ABS structure, we used each band IDFT and synthesis. And we designed non-transfer band for performance by inserting comfort noise. We propose coder that has low bit rate and similar performance comparing with original 10.4 kbps AMR-WB+ TCX mode.

• Proceedings of the Korean Society of Life Science Conference
• /
• 2004.10a
• /
• pp.22-26
• /
• 2004

A self-replicating RNA ligase ribozyme was converted to a cross-catalytic format whereby two ribozymes direct each other's synthesis from a total of four component substrates. Each ribozyme binds two RNA substrates and catalyzes their ligation to form the opposing ribozyme. The two ribozymes are not perfectly complementary, as is the case for replicating nucleic acid genomes in biology. Rather, the ribozymes contain both template elements, which are complementary, and catalytic elements, which are identical. The specificity of the template interactions allows the cross-catalytic pathway to dominate over all other reaction pathways. In the presence of $2{\mu}M$ each of the corresponding substrates, one ribozyme catalyzes the synthesis of the second ribozyme with an initial rate of $6.8{\times}10^{-3}\;min^{-1}$, while the second ribozyme catalyzes the synthesis of the first with an initial rate of $2.9{\times}10^{-3}min{-1}$. As the concentration of the two ribozymes increases, the rate of formation of additional ribozyme molecules increases, consistent with the overall autocatalytic behavior of the reaction system. Here, I present results that possibly demonstrate a clue for a self-replicating molecule by showing an RNA ligase ribozyme, which is reminiscent of 'Prebiotic Era'.