• Journal of the Korean Institute of Gas
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• v.8 no.2 s.23
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• pp.1-7
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• 2004

The physical properties of rigid polyurethane foam(PUF) synthesized using various types of blowing agents such as water, HFC-365mfc, HFC-245fa, HCFC-l4lb, CFC-11 and n-pentane were studied. The blending effect of blowing agents were also studied. The thermal conductivity, reaction rate, and cell morphology of the PUF with various blending ratio of blowing agents were investigated. The PUF blown by water shows the highest compressive strength among other single blowing agents. The thermal conductivity of PUFs blown by HFC-245fa and HFC-365mfc are close to that of PUFs blown by CFC-11. When HFC-365mfc was mixed with HFC-245fa(30mo1e$\%$) as coblowing agent, the mechanical property shows the highest value among other coblowing agents. It is that the thermal conductivity of PUFs depends on cell size of PUFs as well as thermal conductivity of blowing agent in gaseous form.

• Proceedings of the PSK Conference
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• 2000.10a
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• pp.277.2-277.2
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• 2000

• Textile Coloration and Finishing
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• v.7 no.2
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• pp.70-76
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• 1995

The polyepichlorohydrine(poly(ECH)) was prepared by the condensation polymerization of epichlorohydrine. The cationic agent was prepared from poly(ECH) by amination of poly(ECH) with dimethyleneamine. Pretreatment of cellulosic fabric with the poly(ECH)amine produced a modified fabrics that could be dyed under neutral condition with reactive dye using small amount of the salt. Colour yield of cellulosic fabric were increased by increasing salt concentraction. cationic agent concentration. The optimum condition for colour yield was the concentration of cationic agent 5%(o.w.f), that of NaCl 4g/l, and that of $Na_{2}CO_{3}$5g/l. The dyeing of treated fabrics exhibits improved colour yield and high wash fastness.

• Journal of Energy Engineering
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• v.23 no.4
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• pp.141-149
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• 2014

In the present study, pure RHO zeolite was hydrothermally synthesized by using 18-crown-6 ether as a structure directing agent(SDA), and the small gases adsorption was investigated. Synthesized RHO zeolite was a cube shape particle of which average edge length was around $1.2{\mu}m$ and composed of primary crystallites having a diameter of around 100 to 200 nm. RHO zeolite structure was stable under 3h calcination at $600^{\circ}C$. Water adsorption data announced that RHO zeolite has a specific surface area of 483.32 m2/g and its micropore diameter was about 4 A. Gas adsorption was studied in the pressure range of 50 to 500 kPa for $CO_2$, $N_2$, $O_2$ and $H_2$. It was evident that RHO zeolite showed a strong $CO_2$ adsorption behavior. Especially, RHO zeolite showed a transient $CO_2$ adsorption behavior. The 3h $CO_2$ up-take at 50 kPa and 500 kPa was 1.283 and 3.357 mmol/g, respectively. The $CO_2/H_2$ selectivity was around 16 at 500 kPa. Compared with gas adsorption data for some representative microporous adsorbents, it was certain that RHO zeolite is a beneficial adsorbent for $CO_2/H_2$ separation.

• Journal of the Korean Magnetic Resonance Society
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• v.14 no.1
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• pp.9-17
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• 2010

The water proton relaxation rates increase linearly with concentrations of contrast agents, and could be expressed as a function of the concentrations. In this paper, we have investigated MR properties of two different contrast agents, $GdCl_3$ and $CoCl_2$. Relaxivity coefficients were calculated from individual contrast agent solutions, and used for predicting relaxation rates at mixtures of two contrast agents. From the experimental results, we have discussed the feasibility of constructing water solutions with the desired relaxation times using specific mixtures of contrast agents.

• KIEE International Transactions on Power Engineering
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• v.5A no.2
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• pp.125-131
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• 2005

Service restoration is one of the most important missions in distribution system operation. This paper proposes a multi-agent system approach to distribution system restoration. Every relay is developed as an agent by adding its own intelligent, self-tuning and communication ability. The relay agent independently calculates and corrects its restoration index through communication with neighboring agents and its own intelligence. The proposed algorithm is applied to a simple network to demonstrate its soundness and effectiveness.

• Transactions on Electrical and Electronic Materials
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• v.15 no.2
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• pp.81-86
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• 2014

The process parameter in optimized KOH alkali activation of soft carbon series coke material in high purity was set with DOE experiments design. The activated carbon was produced by performing the activation process based on the set process parameters. The specific surface area was measured and pore size was analyzed by $N_2$ absorption method for the produced activated carbon. The surface functional group was analyzed by Boehm method and metal impurities were analyzed by XRF method. The specific surface area was increased over 2,000 $m^2/g$ as the mixing ratio of activation agent increased. The micro pores in $5{\sim}15{\AA}$ and surface functional group under 0.4 meq/g were obtained. The contents of the metal impurity in activated carbon which is the factor for reducing the electrochemical characteristics was reduced less than 100 ppm through the cleansing process optimization. The electrochemical characteristics of activated carbon in 38.5 F/g and 26.6 F/cc were checked through the impedance measuring with cyclic voltammetry scan rate in 50~300 mV/s and frequency in 10 mHz ~100 kHz. The activated carbon was made in the optimized activation process conditions of activation time in 40 minutes, mixing ratio of activation agent in 4.5 : 1.0 and heat treatment temperature over $650^{\circ}C$.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.4
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• pp.272-279
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• 2003

In this work Zn$_4$GeSe$_{6}$ :CO$^{2+}$ single crystals were grown by the chemical transport reaction method in which the iodine was used as the transporting agent. The Zn$_4$GeSe$_{6}$ :CO$^{2+}$ single crystal was found to have a monoclinic structure. The optical absorption spectra of grown crystals were investigated using a temperature-controlled UV-VIS -NIR spectrophotometer. The temperature dependence of band-edge absorption was in a good agreement with the Varshni equation. The observed impurity absorption peaks could be explained as arising from the electron transition between energy levels of Co$^{2+}$ ion sited at the T$_{d}$ symmetry point.

• Proceedings of the PSK Conference
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• 2001.04a
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• pp.132.2-133
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• 2001

• Proceedings of the SCSK Conference
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• 2003.09a
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• pp.601-610
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• 2003

Biotin is a water-soluble vitamin used as a skin conditioning agent and promotes the formation of intercellular lipid layers through increased lipid synthesis, which improves the skin's natural barrier function. The anti-inflammatory effects of biotin have been investigated using in vitro assay models, such as MTT assay, measurements of concentrations of nitric oxide(NO), prostaglandin E2(PGE$_2$), and inhibition rate of 5-lipoxygenase(5-LOX). In comparison with biotin, other plant extracts were tested at the same time which were kudzu vine extract, sage extract, paeonia extract, and dipotassium glycyrrhetinate. Nitric oxide is a signal molecule with functions such as neurotransmission, local vascular relaxation, and anti-inflammation in many physiological and pathological processes. NO can cause apoptosis and necrosis of target cells such as keratinocytes and is generated from L-arginine by nitric oxide synthase (NOS). Prostanoids, including prostaglandins and thromboxanes, are generated by the phospholipase $A_2$/cyclooxygenase(COX) pathway, and leukotrienes are generated by the 5-lipoxygenase pathway from arachidonic acid. Prostaglandin E2 recently have been shown to be beneficial in the resolution of tissue injury and inflammation, also has been implicated as an immunosuppressive agent and plasma levels of PGE$_2$ are elevated in patients sustaining thermal injury. Lipoxygenase metabolites from arachidonic acid have been implicated in inflammation, anti-inflammatory activity of the raw materials was evaluated in vitro by the offered inhibition of lipoxygenase.