• Proceedings of the KOSOMBE Conference
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• v.1997 no.11
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• pp.478-481
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• 1997

A technique or the preparation of porous polyurethane vascular prostheses was investigated. Small-diameter vessels are not in general clinical use due to their limited long-term biocompatibility and low patency rates in experimental trial. These limits are mainly due to the failure of mechanical unction of the vascular grafts. This failure has been suggested to result partially from compliance mismatch. The long-term patency is considered to depend critically on the properties of the material and the fabrication process of the graft. So the control of pores is very important and main points to develop a available vascular grafts. Two-kind polymer sheets was compared. One was the porous PU-sheet made at room temperature by the solvent/non-solvent exchange. And the other was the porous PU-sheet which was fabricated by thermal phase transition and solvent-/non-solvent exchange using the thermal controller. The polymer sheets had a uniform pore size and pore occupation. According to the result of the above experiments, polyurethane solution was injected into a mold designed or U-type tube. The average pore size and pore occupation were easily changed by changing polyurethane concentration, freezing temperature, and methods. This technique can give a proper pore size ($10{\sim}45\;{\mu}m$) or tissue in growth, and suitable compliances or matching with arteries and veins. Besides, the fabrication of more complicated shaped vessels such as the U-type vascular grafts is easily controlled by using the fixed mold. this method might give a desired compliant graft or artificial implantation with the presently valid medical polymers.

• Korean Journal of Food Science and Technology
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• v.21 no.6
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• pp.851-856
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• 1989

The physical properties of essential oil of nutmeg extracted in different methods (SDE, Solvent, $CO_2$) were investigated and also the components of essential oil were analyzed using G.C. and G.C./ Mass. Solvent extraction yield was 23% and was higher than those of SDE extraction and $CO_2$ extraction. From the analysis result and physical properties of nutmeg oil, it was conformed that the nutmeg used In this experiment was similar to East Indies type. The content of sabinene was 3.6-14.1%, 28.4-48.7% for myristicin, 1.2-2.1% for elemicin, and 3.6-5.6% for safrole. The camphene was identified in SDE extracts but not in $CO_2$ extracts. The volatile components of SDE extracts and solvent extracts contained large amount of monoterpene and terpene alcohol but $CO_2$ extracts aminly contained aromatic compounds.

• Journal of the Korean Graphic Arts Communication Society
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• v.22 no.2
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• pp.199-211
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• 2004

The drying speed of gravure ink are very fast because of evaporation drying type. The gravure ink are fitly selected variety resin and solvent for a wide range printing are adopted. Moreover, after-manufacture handling is necessary to various purposes. Though composition of gravure ink are same those of another printing ink, the viscosity of it are vary low compare with another printing inks. As property of variety printed matters, improvement of performance of printing layer and suitable after-manufacture handling, the more research of gravure ink are to be continue for development of printing technology. Generally, the gravure ink are made up resin, pigment, solvent and additive. Especially solvent are fitly selected for solution of resin, viscosity, and drying speed. Furthermore, it tis care of bad smell of remaining resin, poison and danger of fire of it. Because of the prevention of air pollution as restriction deflation of solvent, custody of dangerous object and improvement of work environment as labor safety hygiene and fire-low, the environment restriction of printing business become strict. This study has purpose of development of gravure ink of involved 30% below of alcohol is used for PVC film printing.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2000.04a
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• pp.142-144
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• 2000

• Journal of the Korean Applied Science and Technology
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• v.29 no.2
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• pp.199-204
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• 2012

Organic thin-film transistors (OTFTs) have received considerable attention because their potential applications for nano-scale thin-film structures have been widely researched for large-scale integration industries, such as semiconductors and displays. However, research in developing n-type materials and devices has been relatively shortage than developing p-type materials. Therefore, we report on the fabrication of top-contact [6,6]-phenyl-C61-butyricacidmethylester (PCBM) TFTs by using three different solvent, o-dichlorobenzene, toluene and chloroform. An appropriate choice of solvent shows that the electrical characteristics of PCBM TFTs can be improved. Moreover, our PCBM TFTs with the cross-linked Poly(4-vinylphenol) dielectric layer exhibits the most pronounced improvements in terms of the field-effect mobility (${\sim}0.034cm^2/Vs$) and the on/off current ratio (${\sim}1.3{\times}10^5$) for our results. From these results, it can be concluded that solvent-modification of an organic semiconductor in PCBM TFTs is useful and can be extended to further investigations on the PCBM TFTs having polymeric gate dielectrics. It is expected that process optimizations using solution-processing of organic semiconductor materials will allow the development of the n-type organic TFTs for low-cost electronics and various electronic applications.

• Korean Chemical Engineering Research
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• v.44 no.2
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• pp.227-233
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• 2006

Solvent extraction of pentachlorophenol (PCP) from wood chips of the PCP-treated ammunition box has been studied using methanol, ethanol and acetonitrile. Experimental variables were chosen as the composition of solvents, the ratio of solvent per dried wood, size of the substance, extraction temperature and sonication applied to the samples. The average concentration of PCP was 720 ppm and methanol was the most effective for PCP extraction. Above 99％ of PCP were removed from the sample (initial concentration of PCP; 1297 ppm) within 2 h at room temperature by methanol. The minimal ratio of methanol per dried wood chip(v/w) was 10. Type of substances(chip or sawdust), extraction temperature and sonication showed little effects on PCP extraction.

• Journal of the Korean Applied Science and Technology
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• v.22 no.1
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• pp.50-55
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• 2005

A comparison of alkali metal cation and alkaline earth cation solvent extraction was made for three additional monoionizable crown ethers and one diionizable crown ether. sym-(n-Octyldibenzo)-16-crown-5-oxyacetic acid $\underline{1}$ exhibited high efficiency and selecvity in solvent extraction of alkali metal cations with respect to that observed with alkaline earth cations. Sizes of $Na^+$ and $Ca^{2+}$ appropriately match with the cavity size of monoethyl sym-bis[4(5)-tert-butylbenzo]-16-crown-5-oxymethylphosphonic acid $\underline{3}$. As the result, $Na^+$ and $Ca^{2+}$ are the best extracted. sym-(n-Octyldibenzo)-16-crown-5-oxymethyldiphosphonic acid $\underline{4}$was found to be somewhat selective for $Na^+$ over $Li^+$ and other alkaline earth metal cations. In the complexation of alklaine earth cations by crown ether diphosphonic acid $\underline{4}$, $Ca^{2+}$ and $Sr^{2+}$ are the appropriate sizes, but lager $Ba^{2+}$ may be due to favorable formation of a sandwich type complex between the crown ether cavity and the dianion of the deprotonated crown ether phoaphonic acid moiety.

• ETRI Journal
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• v.33 no.6
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• pp.887-896
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• 2011

We investigated the effects of a gate dielectric and its solvent on the characteristics of top-gated organic field-effect transistors (OFETs). Despite the rough top surface of the inkjet-printed active features, the charge transport in an OFET is still favorable, with no significant degradation in performance. Moreover, the characteristics of the OFETs showed a strong dependency on the gate dielectrics used and its orthogonal solvents. Poly(3-hexylthiophene) OFETs with a poly(methyl methacrylate) dielectric showed typical p-type OFET characteristics. The selection of gate dielectric and solvent is very important to achieve high-performance organic electronic circuits.

• International Journal of Industrial Entomology and Biomaterials
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• v.41 no.2
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• pp.36-44
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• 2020

Mulberry root bark is one of potential plant sources for antioxidant materials which can be used for the relief of oxidative stress. To explore the effects of solvent type and temperature on the structural characteristics and antioxidant activity of the root bark extracts, we prepared various extracts of mulberry root bark (Morus alba L.) using 0 - 100 % ethanol (EtOH) at RT - 100℃. EtOH concentration and temperature critically affected the extraction yields, the content of bioactive components, and antioxidant activity of the extracts. Use of high content of EtOH solvent and low temperature resulted in the low extraction yield. Meanwhile, it was revealed that the extract prepared using absolute EtOH at room temperature contained polyphenols and flavonoids with the highest contents among other extracts. Interestingly, the temperature differently affected the polyphenol and flavonoid contents according to the solvent types. In the case of 30% EtOH solvent, polyphenol and flavonoid contents increased with an increase in temperature, whereas in the case of 70 and 100 % EtOH, these contents decreased. Using the radical scavenging assay, it was confirmed that the 100% EtOH extracts had higher antioxidant activity compared to distilled water (DW) extracts regardless of temperature. Also, heating might extract more antioxidant components from the root bark. Especially, the extract prepared using 30% EtOH solvent at 100℃ showed the highest antioxidant activity. Taken together, these experimental results imply that the extraction parameters should be designed carefully considering the productivity, the extracted bioactive components, and antioxidant activity.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.1 no.1
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• pp.39-50
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• 1991

Single crystals of yttrium iron garnet $(YIG:Y_3Fe_5O_{12})$have been grown by a modified floating zone crystal growth technique(Traveling Solvent Floating Zone, TSFZ method) using an infrared radiation convergence type heater. A series of evaluations for the resulting YIG single crystals were carried out. The grown crystals are 5~6mm in diameter and 15~35mm in length. The conditions of single crystal growth were as follows; growth rate 1mm/h, rotation rate 30rpm, gas flow rate 0.2 1/min., zone aspect ratio 1, convexity of interface 0.29, respectively.