• Polymer(Korea)
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• v.31 no.6
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• pp.474-478
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• 2007

Polymer substrate materials with low dielectric loss were obtained by fabricating the composite using dicyclopentadienyl bisphenol cyanate ester oligomer and polyphenylene ether (PPE). From the analysis of the curing reaction of oligomer and catalyst, it was observed that the optimum amount of catalyst was 0.02 phr of Zn content. It was applied to the fabrication of polymer composite. By changing oligomer/PPE weight ratio, the peel strength and the gel content of the fabricated composites were measured, and then, the dielectric constant and the dissipation factor were measured in the GHz frequency range. The amount of PPE affected the peel strength and the dielectric properties of composites. However, the amount of catalyst did not affect them at all. Resulting from all experiments, we obtained polymer composite laminates haying the peel strength of above 1 kN/m and the low dissipation factor of 0.004 at 1 GHz.

• Proceedings of the Ginseng society Conference
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• 1988.08a
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• pp.36-38
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• 1988

We have studied the ginsenoside effect on DNA RNA and protein synthesis in bone marrow. Ginseng was found to have a beneficial effect on ${\alpha}-napthyl-isothio-cyanate-induced$ hepatobiliary damage. Stimulatory effects of some ginsenosides were shown for cell proliferation and DNA synthesis in a culture liver cell line. The clinical applicability of ginseng on liver diseases will be discussed in relation to traditional medicine.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.111-111
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• 2010

최근 전자 소자의 집적기술은 기존의 2차원에서 System on package (SOP) 개념에 기반을 둔 3차원 집적 기술로 발전 되어가고 있다. 소자의 3차원 실장을 실현시키는 과정에서 세라믹의 여러 유용성이 언급되어져 왔지만, 취성이 매우 크다는 등의 단점이 있었다. 이러한 이유로 연성을 가지는 폴리머와 세라믹을 합성한 복합체 기판에 대하여 많은 연구가 되고 있다. 그러나 세라믹 제작을 위해서는 높은 공정온도가 요구되고 있고 이러한 높은 공정상에서의 온도는 3차원 실장에 있어서 문제점이 되고 있다. 이러한 문제점을 극복하기 위하여 상온에서 치밀한 세라믹 후막을 제작할 수 있는 공정인 Aerosol Deposition Method (ADM)방법으로 세라믹-폴리머 후막의 제조를 시도하였다. 일반적으로 ADM은 수백 나노의 출발 파우더를 사용하여 치밀한 세라믹 막을 형성하는데 사용된다. 본 연구에서는 ADM으로 100 nm미만의 나노 세라믹 파우더를 사용하여 다공성의 세라믹 후막을 제조한 후 resin을 함침시키는 방법으로 세라믹-폴리머 후막의 제조를 시도하였다. 그 결과 운송가스, aerosol 농도 등의 공정조건을 변화시켜 다공성의 $Al_2O_3$ 후막을 제조하였고, 이 다공성 후막은 반투명의 특성을 보이며 고충전율로 형성되었다. 이렇게 제조된 나노 다공성 $Al_2O_3$ 후막에 cyanate ester resin을 함침시키는 방법을 사용하여 $Al_2O_3$-cyanate ester 복합체 후막을 제조하였으며, 이의 비유전율 및 품질계수는 각각 1 MHz에서 6.7, 1000으로 우수한 유전특성을 보임이 확인되었다.

• Journal of Powder Materials
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• v.15 no.5
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• pp.386-392
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• 2008

Silver particles were synthesized from silver nitrate by homogeneous precipitation and chemical reduction methods involving the intermediate silver cyanate. The obtained silver particles were characterized by XRD, SEM, TEM, and BET. Urea which could prevent the agglomeration of the reduced silver particles was used as a homogeneous precipitator. The spherical silver particles with average particle diameter of 100 nm were obtained under the optimum reaction conditions. The optimum synthetic conditions were found as follows: reaction temperature $100^{\circ}C$, reaction time 60 min, concentration of silver nitrate $1{\times}10^{-2}$ mol, urea $5{\times}10^{-3}$ mol, and sodium citrate $8.5{\times}10^{-4}$ mol. The phase of obtained silver particles was crystalline state and the silver particles were relatively dense, which had the surface area of $0.7571\;m^{2}/g$.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.4
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• pp.297-302
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• 2009

We have successfully fabricated the alumina thick films using inkjet printing processes without a high temperature sintering process. Alumina suspension as dielectric ink was formulated by combining nano-sized alumina powders with an anionic polymer dispersant in formamide/water as co-solvent. The thickness of the printed alumina thick film was measured at around 5 um by field emission scanning electron microscope. The calculated packing density of 68.5 % from the printed alumina thick film was much higher than the same films fabricated by conventional casting or dip coating processes. Q factor of the dielectrics thick film infiltrated with cyanate ester resin was evaluated by impedance analyzer.

• Environmental Engineering Research
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• v.11 no.6
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• pp.318-324
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• 2006

The higher valence state of iron i.e., Fe(VI) was employed for the oxidation of one of an important toxic ion, cyanide in the aqueous medium. Cyanide was oxidized into cyanate, which is 1,000 times less toxic to cyanide and often accepted for its ultimate disposal. It was to be noted that Fe(VI) is a very powerful oxidizing agent and can oxidize most of the cyanide within few minutes i.e., ca 5 mins of contact. The data was obtained by the UV-Visible measurements for the Fe(VI) decomposition. The UV-Visible data was used to evaluate the overall rate constant for second order redox reaction between ferrate(VI) and cyanide. Also the pseudo first order rate constant was calculated as keeping the cyanide concentration in excess.

• Journal of the Korea Institute of Military Science and Technology
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• v.15 no.2
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• pp.161-168
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• 2012

In this paper, we have experimentally studied on phase characteristics of airborne radome for ELINT directional finding system, because it is difficult to find theoretical solutions for phase error of the radome. Especially, we described the millimeter wave band radome that was fabricated with cyanate-ester material and its thickness was 2mm. We presented the phase error about millimeter band radome. That phase error is about 30 degrees for parallel and perpendicular polarization in the K-Ka band. That is reasonable value for the ELINT directional finding system.

• Bulletin of the Korean Chemical Society
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• v.22 no.12
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• pp.1371-1374
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• 2001

Metal doping was adopted to modify TiO2 (P-25) and enhance the photocatalytic degradation of harmful cyanides in aqueous solution. Ni, Cu, Co, and Ag doped TiO2 were found to be active photocatalysts for UV light induced degradation of aqueous cyanides generating cyanate, nitrate and ammonia as main nitrogen-containing products. The photoactivity of Ni doped TiO2 was greatly affected by the state of Ni, that is, the crystal size and the degree of reduction of Ni. The modification effects of some mixed oxides, that is, Ni-Cu/TiO2 were also studied. The activity of Ni-Cu/TiO2 for any ratio of Cu/Ni was higher than that of Ni- or Cu-doped TiO2, and the catalyst at the Cu/Ni ratio of 0.3 showed the highest activity for cyanide conversion.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.80-80
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• 2009

$BaTiO_3$ has high permittivity so that has been applied to dielectric and insulator materials in 3D system-level package integration. In order to achieve excellent performance of device, the $BaTiO_3$ layer should be highly dense. In this study, $BaTiO_3$ thick films were prepared by the inkjet printing method using 4 vol.% $BaTiO_3$ colloidal inks and cured at $28^{\circ}C$ for 5 h after infiltration of polymer resin for non-sintered process using 3 vol.% cyanate ester emulsion ink. From the obtained results. packing density was determined to be improved by overlapping rabbit ears which were generated by coffee ring effect. We also calculated the packing densities of the films and correlated these packing densities to the measured permittivity of the films.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1997.04a
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• pp.73-73
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• 1997

A series of 4-phenyl-1-(indoline-5-sulfonyl)-2-imidazolone derivatives has been synthesized starting from 2-bromoacetophenone. Reaction of 2-aminoacetophenone obtained from 2-bromoacetophenon by Delepin synthesis and potassium cyanate affords 1,3-dihydro-4-phenyl-2-imidazolone. This key intermediate was treated with sodium hydride and N-trifluoroacetyl-indoline-5-sulfonylchloride, and trifluoroacetyl group was deprotected to give 4-Phenyl-1-(indoline-5-sulfonyl)-2-imidazolone. Various substituents were introduced on the nitrogen of indoline. Antitumor activity of this series of compound was evaluated by MTT method. Nearly all of the compounds showed broad-spectrum activity.