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        검색결과 10

        1.
        2019.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        양이온성 계면활성제 (DTAB, TTAB 및 CTAB)에 의한 아닐린의 가용화현상을 연구하기 위하여 UV-Vis법을 이용하여 가용화상수(Ks)와 열역학 함수들을 계산하고 비교하였다. 그리고 이온염과 유기물의 첨가가 가용화상수에 어떠한 영향을 미치는지를 조사하였다. 또한 온도변화에 따른 Ks값의 변화를 계면활성제 종류별로 비교하고 분석하였으며, 가용화상수로부터 구한 여러 열역학적 함수를 비교하고 검토함으로써 아닐린의 가용화현상을 미시적으로 분석하고 해석하고자 하였다. 그 결과 양이온성 계면활성제에 의한 아닐린의 가용화현상에 대한 Gibbs 자유에너지와 엔탈피 변화 값은 모두 음의 값을 그리고 엔트로피 변화값은 모두 양의 값을 나타내었다. 가용화상수 값은 온도가 증가함에 따라 감소하고 계면활성제의 탄소사슬의 길이가 증가할수록 증가하였다. 이온염의 농도가 증가함에 따라 가용화에 대한 Gibbs 자유에너지값은 증가하다가 감소하는 경향을 보였다. 그리고 n-부탄올의 농도가 증가함에 따라 Gibbs 자유에너지는 계속 증가하는 경향을 보였다.
        4,000원
        2.
        2019.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        아닐린 수용액에서의 암모늄형 양이온성 계성면활성제 (DTAB, TTAB 및 CTAB)의 미셀화에 대한 임계미셀농도(CMC)값을 UV-Vis법으로 측정하였다. 290K ~ 314K 사이에서 측정된 양이온성 계면활성제의 CMC값의 변화로부터 미셀화에 대한 Gibbs 자유에너지(ΔG⁰)값을 구하고, 이 값으로부터 엔탈피(ΔH⁰)와 엔트로피(ΔS⁰)를 계산하고 분석하였다. 또한 n-부탄올 및 염화나트륨의 농도 변화가 미셀화에 미치는 영향을 열역학적 함수를 이용하여 비교·분석하였다. 실험한 온도 구간 및 첨가제의 농도 범위 내에서 측정된 모든 ΔG⁰ 값은 음의 값을 나타냈었으며, 엔탈피(ΔH⁰) 변화값은 모두 음의 값을 그리고 엔트로피(ΔS⁰) 변화값은 모두 양의 값을 나타내었다. 아닐린 수용액에서 양이온성 계면활성제의 미셀화는 자발적 발열반응이며, 열역학적 값들로부터 계산된 등구조온도에 의하면 이들 계면활성제의 미셀화는 엔탈피(ΔH⁰)와 엔트로피(ΔS⁰)가 거의 동일하게 기여하고 있음을 알 수 있었다.
        4,000원
        3.
        2014.11 구독 인증기관·개인회원 무료
        4-isopropyl-2,6-bis(1-phenylethyl)aniline 1 (KTH13-AD1) is a metabolite of Cordyceps bassiana that has been traditionally used to treat various inflammatory disease. Even though it has the magnificent pharmaceutical potential, there was not much understanding on its anti-inflammatory actions. Therefore, this study was aimed to determine the anti-inflammatory effects of KTH13-AD1. We found that KTH13-AD1 suppressed nitric oxide (NO) and reactive oxygen species (ROS) production in lipopolysaccharide (LPS)- or sodium nitroprusside (SNP)-treated macrophages (RAW264.7 cells). Similarly, mRNA expression of inducible NO synthase (iNOS) and tumor necrosis factor-a (TNF-a) analyzed by RT-PCR and real-time PCR was also reduced by this compound. Interestingly, KTH13-AD1 also strongly diminished the levels of NF-kB-mediated luciferase activities and nuclear translocated NF-kB family proteins. In agreement with these, KTH13-AD1 suppressed the upstream signaling pathway for NF-kB activation including IkBa, IKKa/b, AKT, p85/PI3K and Src in time- and dose-dependent manners. Therefore, these results strongly suggest that KTH13-AD1 has a strong anti-inflammatory activity via suppression of the NF-kB signaling pathway.
        4.
        2014.05 구독 인증기관·개인회원 무료
        Purpose: The physical and optical characteristics for copolymers produced by adding 3-Iodoaniline and 3-chloroaniline to the various monomers commonly used for ophthalmic contact lenses were investigated. Methods: The basic hydrogel ophthalmic lens material with addition of 3-Iodoaniline and 3-chloroaniline respectively were polymerized by heating at 80℃ for 20 mins, and then 110 ℃ for 40 mins. To produce contact lenses, a cast mould method was used. The produced contact lenses samples underwent the pre-process by being hydrated in 0.9% NaCl saline for 24 hours. Afterward, their physical and optical properties were measured. Results: The results showed that the average value of refractive index increased and the water content decreased as the ratio of additive increased. The measurement of the optical transmittance of the copolymerized polymer with addition 3-Iodoaniline showed that the transmittance for visible ray, UV-B and UV A is 89.4~90.8%, 2.0~15.2% and 40.6~67.8%, respectively. Also, for samples with addition 3-Iodoaniline, the transmittance for visible ray, UV-B and UV-A was in the range of 89.8~90.6%, 5.0~22.2% and 57.6~73.8% respectively. Conclusions: It is expected that the results would contribute to a wider application of contact lenses containing aniline group which are to be used as ultraviolet ray blocking contact lenses.
        5.
        2013.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Lead (II) ion selective poly(aniline) solid contact electrode based on Tetramethylthiuram monosulfide ionophore as a sulfur containing sensing material is successfully developed. The electrode exhibits good linear response of 25.6 mV / decade (at 20±0.2℃, r2=0.995) within the concentration range of 1.0×10-1~4.0×10-7 M Pb (II). The composition of this electrode was Ionophore : PVC : dioctylphthalate : potassiumtetrakis(4-chlorophenyl)borate : Oleic acid = 5.0 : 20.0 : 25.0 : 4.0 : 5.0. When we consider the results of using different composition electrodes based on only one potassiumtetrakis(4-chlorophenyl)borate or Oleic acid liphophlic additive, poly(aniline) solid contact electrode based on Tetramethylthiuram monosulfide ionophore with potassiumtetrakis(4-chlorophenyl)borate and Oleic acid liphophlic additive had the best result in response characteristics. The electrode shows good selectivity for lead (II) ion in comparison with alkali, alkaline earth, transition and heavy metal ions. This electrode is suitable for use with aqueous solutions of pH 3.0 ~ 7.0 and their standard deviation in the measured emf differences was ±2.94 mV at Tris buffered lead sample solution of 1.0×10-2 M and ±2.82 mV at Tris buffered lead sample solution of 1.0×10-3 M. Their stabilization time was less than 710 s. and response time was less than 16 s.
        4,000원
        6.
        2013.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, polyaniline (PANI)/graphene nanosheet (GNS) composites were synthesized through chemical oxidation polymerization by changing the weight ratio of aniline mono-mers. To examine the morphological structure of the composites, scanning electron micros-copy and transmission electron microscopy (TEM) were conducted. TEM results revealed that fibril-likePANI with a diameter of 50 nm was homogeneously coated on the surface of the GNS. The electrochemical properties of the composites were studied by cyclic voltam-metry in 1 M H2SO4 electrolyte. Among the prepared samples, the PANI/GNS (having 40 wt% aniline content) showed the highest specificcapacitance, 528 Fg-1, at 10 mVs-1. The im-proved performance was attributed to the GNS, which provides a large number of active sites and good electrical conductivity. The resulting composites are promising electrode materials for high capacitative supercapacitors.
        3,000원
        8.
        1998.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study is to develop a new synthetic method for the nitroarenes via non-electrophilic substitution. Direct nitration at the C-1 position of isoquinoline has never been reported and substitution in isoquinoline under the normal nitration condition occurs at C-5 and C-8. We have demonstrated a facile one-step sythetic method for the nitration of isoquinolines at the C-1 position, which involves the electrophilic attack of a DMSO-Ac2O complex, followed by nucleophilic addition of nitrate ion to this intermediate. Since the reaction is simple and mild, this method has preparative merit since 1-nitroisoquinolines are not readily accessible by other methods. Application to the synthesis of poly nitroarenes from the corresponding anilines was also described.
        4,000원
        9.
        1991.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The kinetic of hydrolysis for cinnamylidene aniline derivatives has been investigated by ultraviolet spectrophotometry in 20% (v/v) dioxane - H2O at 25℃. A rate equation which can be applied over wide pH range was obtained. The substituent effects on cinnamylidene aniline derivatives were studied and the hydrolysis was facilitated by electron attracting group. Final products of the hydrolysis were cinnamaldehyde and aniline. From the rate equation, substituent effect and final products, the hydrolysis of cinnamylidene aniline derivatives was initiated by the neutral molecule of H2O which does not dissociate at below pH 9.0~12.0, but proceeded by the hydrogen ion at above pH 5.0~9.0.
        4,000원