• Journal of Photoscience
• /
• 제5권2호
• /
• pp.47-51
• /
• 1998

Direct irradiation of 1Z,3E-1-cyano-1,4-diphenylbutadiene (2) and 1Z,3E-1-cyano-3-methyl-1,4-diphenylbutadiene (3) in organic solvents viz. n-hexane, methanol and acetonitrile results in preferential isomerization of the double bond substituted with cyano group via one-photon-one-bond isomerization process. The quantum efficiency of the isomerization of 3 is more than 2 in all the three solvents. Photoproducts of 2 and 3 (viz. 2a, 2b, 3a, 3b) also exhibited similar photoisomerization trends. The results are discussed in terms of the effects of substituents on the potential energy surface of the excited singlet states of $\alpha$,$\omega$-diphenylpolyenes, and the role of zwitterionic dipolar species in the photoisomerization process of linearly conjugated C=C polyenes is highlighted.

• 한국정보디스플레이학회:학술대회논문집
• /
• 한국정보디스플레이학회 2000년도 제1회 학술대회 논문집
• /
• pp.191-192
• /
• 2000

New copolyimides containing nitrile side group were synthesized from copolymerization of pyromellitic dianhydride, m-phenylene diamine and 3,5-diaminobenzonitrile and subsequent thermal imidization of the resulting poly(amic acid). Crystallinity, glass transition temperature and initial decomposition temperature of copolyimides were almost identical to those of homo polyimide prepared from PMDA and m-PDA. Change of pretilt angle induced by the orientation layer of resulting copolyimide was investigated by using a nitrile-containg nematic liquid crystal cell after rubbing. As the content of polar nitrile group was increased in the copolymer, pretilt angle was increased from $3.65^{\circ}$ to $6.49^{\circ}$. The mechanism of this was speculated as the dipolar interaction between the liquid crystal and nitrile groups in copolyimide.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1987년도 정기총회 및 창립40주년기념 학술대회 학회본부
• /
• pp.489-491
• /
• 1987

It has been shown that the thermally stimulated current technique can be one of the most powerful methods for evaluating the electrical properties. An unstretched $\alpha$-form specimen of corona-charged, 50[${\mu}m$],t Polyvinylidene Fluoride shows four TSC peaks designated $\delta}$, $\gamma$, $\beta$ and $\alpha$ in assending order of temperature in temperature range $-100{\sim}200^{\circ}C$. The $\delta$, $\gamma$ peaks may be attributed to the dipolar depolarization in the amorphous regions and $\beta$, $\alpha$ peaks are associated with the detrap from trapped carriers in the crystalline regions.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1987년도 정기총회 및 창립40주년기념 학술대회 학회본부
• /
• pp.511-514
• /
• 1987

Langmuir-Blodgett (LB) films of TCNQ(tetracyanoquinodimethane) with alkyl radical($C_{12}TCNQ$) were prepared on the sample of Al/LB film/Al type where Al are electrode, and polarization in LB film and dipolar moment of molecules in the films were measured by TSC. $Al_2O_3$ layer was yielded on the electrode by natural oxidation in air. According to the cooperation of $Al_2O_3$ dielectric layer and the polarization of $C_{12}TCNQ$-LB film, the macroscopic electrical field was yielded in LB film and $Al_2O_3$ layer. The field strength in $C_{12}TCNQ$-LB films was evaluated at about $1{\times}10^6{\sim}5{\times}10^6\;V/cm$.

• 한국자기학회:학술대회 개요집
• /
• 한국자기학회 2013년도 자성 및 자성재료 국제학술대회
• /
• pp.99-100
• /
• 2013

• 대한화학회지
• /
• 제43권3호
• /
• pp.302-306
• /
• 1999

Quinoxaline 4-oxide 10을 2-chloroacrylonitrile과 반응시켜 1,3-쌍극성 고리화 첨가반응으로 2,3-dihydro-1H-1,2-diazepino[3,4-b]quinoxaline류 11a, b를 합성하였고, 이들을 2,3,4,6-tetrahydro-1H-1,2-diazepino-[3,4-b]quinoxaline 12로 변환시켰다. 그리고 ??嵐?11a를 아세트산/물 용매에서 SeO2와 반응시켜서 고리변환에 의해 1,4-dihydro-4-oxopyridazino[3,4-b]quinoxaline 13을 합성하였다.

• 한국정보통신학회:학술대회논문집
• /
• 한국정보통신학회 2018년도 추계학술대회
• /
• pp.526-528
• /
• 2018

본 논문은 Wi-Fi 환경내 스마트기기의 무선전력전송을 위한 유연한 소형 다이폴 안테나를 제안한다. 제안된 안테나는 중앙에 분할고리공진기를 가진 다이폴 안테나 구조이며, 크기가 32mm인 소형 다이폴 안테나이다. 분할고리공진기 다이폴 안테나는 동일 크기의 다이폴 안테나에 비해 약 20% 파장을 줄이는 결과를 보였다.

• Bulletin of the Korean Chemical Society
• /
• 제24권7호
• /
• pp.981-985
• /
• 2003

Fluorine-19 NMR solution measurements have been made for various phenyl-fluorinated iron porphyrin complexes. Large chemical shifts for phenyl fluorine signals of iron(III) and iron(II) are observed, and these signals are sensitive to electronic structure. The chemical shift differences in ortho-phenyl fluorine signals between high-spin ferric and low-spin ferric tetrakis(pentafluorophenyl)porphyrins are approximately 40 ppm, whereas the differences are approximately 7 ppm between high- and low-spin states of ferrous tetrakis(pentafluorophenyl)porphyrin complexes. Analysis of fluorine-19 isotropic shifts for the iron(III) tetrakis(pentafluorophenyl) porphyrin using fluorine-19 NMR indicates there is a sizable contact contribution at the ortho-phenyl fluorine ring position. Large phenyl fluorine-19 NMR chemical shift values, which are sensitive to the oxidation and spin states, can be utilized for identification of the solution electronic structures of iron(III) and iron(II) porphyrin complexes.

• 대한화학회지
• /
• 제55권2호
• /
• pp.240-242
• /
• 2011

CuCl과 N-methyl-2-pyrrolidone을 이용하여 5-bromoindole을 halogen - halogen 교환반응을 통하여 5-chloroindole계 화합물을 합성하는 one-pot대량합성방법을 개발하였다.

• Bulletin of the Korean Chemical Society
• /
• 제30권1호
• /
• pp.157-162
• /
• 2009

General, fast, and efficient methods for the synthesis of Fréchet-type dendrimers having core diversities were elaborated. Two core building blocks, 4,4'-(3,5-bis(propargyloxy)benzyloxy)bisphenyl and N,N,N',N'-tetra(prop-2- ynyloxycarbonylethyl)-1,2-diaminoethane, were designed to serve as the alkyne functionalities for dendrimer growth via click reactions with the azide-dendrons. The synthetic strategy involved an 1,3-dipolar cycloaddition reaction between an alkyne and an azide- functionalized Fréchet-type dendrons in the presence of Cu(I) species which is known as the best example of click chemistry.