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        • SCOPUSKCI등재

          메탄올-물 혼합액에서의 n-Alkylamine 염산염의 분 몰랄 부피

          엄태섭,윤상기,이익춘,Uhm, Tae-Sup,Yoon, Sang-Ki,Lee, Ik-Choon 대한화학회 1970 대한화학회지 Vol.14 No.1

          Methyl에서 n-butyl까지의 n-alkylamine 염산염동족체($RNH_3Cl$)의 "겉보기몰랄부피"(apparent molal volume)${\phi}_v$를 30$^{\circ}C$에서 여러가지 조성의 methanol-물 혼합액을 써서 측정하였다. 아민염의 농도는 0.01M까지, 밀도는 부력법을 적용하여 소수점이하 5위까지 택하였다. 관측된 ${\phi}_v$값을 무한대의 농도 쪽으로 extapolation하여 "분몰랄부피"(partial molal volume)$\bar{V}^{\circ}$V를 구하였다. 실험결과는 용질입자의 크기, charge 및 hydrophobic effect등에 관하여 논의되었고 또한 동족체간에일정한 몰랄부피차(${\Delta}\bar{V}^{\circ}$)를 갖는다는 사실과 아울러 혼합용매의 구조에 대하여도 검토하였다. 메탄올-물 0.1몰분율(m.f.)에서는 물의 구조증대로 cation의 "분몰랄부피($\bar{V}^{\circ}_+$)가 최소이고, 한편 0.4m.f. 에서는 charge 효과에 의한 electrostriction effect의 최대화 free volume이 최소라는 사실들이 관찰되었다. The apparent molal volumes(${\phi}_v$) of the homologous salts $RNH_3Cl$, where R varies from methyl-($CH_{3^-}$) to n-butyl-(n-$C_4H_{9^-}$) in a series of methanol-water mixtures have been determined at 30$^{\circ}C$ by means of a float method to fifth decimal places down to 0.01 m. The values of ${\phi}_r$ extrapolated to infinite dilution give partial molal volumes $\bar{V}^{\circ}$which varies considerably in accordance with the solvent composition. that is, mole fraction of methanol. The experimental results are discussed in terms of the varying size and charge effect, hydrophobic nature of the solute species, and also the additivity relationship between successive homologous and the structure of the binary solvent. The results indicate that at 0.1 mole fraction methanol the enhanced structuredness of water cause a minimum in the partial molal volumes of cations $\bar{V}^{\circ}_+$, while at 0.4 mole fraction the solvent structure is such that the free volume is a minimum but the effect of electrostriction is a maximum.

        • SCOPUSKCI등재

          황의 친핵성 치환반응 (제9보). 물-아세톤 혼합용매 속에서 1-염화 및 2-염화나프탈렌 술포닐의 가용매 분해반응

          엄태섭,이익춘,이억석,Uhm Tae Seop,Lee Ik Choon,Lee Euk Suk 대한화학회 1977 대한화학회지 Vol.21 No.4

          1-염화 및 2-염화나프탈렌술포닐의 가용매 분해반응을 아세톤-물혼합용매속에서 전기전도도법으로 실시하여 여러가지 용매 파라미터 및 활성화파라미터와 관련지워 용매효과와 반응 메카니즘을 논의하였다. 반응은 $S_N2$ 메카니즘으로 진행되나 물함량이 크면 bond-breaking이 약간 증가한다. 또한 바닥상태 안정화효과와 천이상태에서의 peri-hydrogen효과 때문에 2-나프탈렌 화합물의 반응속도가 1-나프탈렌 화합물의 반응속도보다 빨랐으며 이 효과는 에탄올-물 혼합용매속에서와 비슷하였다. The solvolysis of 1-naphthalene-and 2-naphthalenesulfonyl chlorides in acetone-water mixtures have been studied by means of conductometry. The solvent effect and mechanism have been discussed in terms of variation in solvent composition and activation parameters. The reaction was predominantly $S_N2$ type, but bond breaking increased with the increase of water content. The rate constant for 1-naphthyl compound was smaller than that of 2-naphthyl compound due to the ground state stabilization effect and peri-hydrogen effect, and the latter effect was similar to that in ethanol-water mixtures.

        • SCOPUSKCI등재

          황의 친핵성 치환반응 (제8보). 물-에탄올 혼합용매 속에서 1-및 2-염화나프탈렌 술포닐의 가용매 분해반응

          엄태섭,이익춘,김재록,Uhm, Tae Seop,Lee, Ik Choon,Kim, Jae Rok 대한화학회 1976 대한화학회지 Vol.20 No.5

          물-에탄올 혼합용매속에서 1-염화 및 2-염화나프탈렌술포닐의 두 나프틸 화합물의 가용매 분해반응을 전기 전도도법을 사용하여 속도론적으로 연구하였다. 연구결과 2-나프틸 화합물의 반응속도상수가 1-나프틸 화합물의 것보다 컸다. 이것은 MO이론의 예측과는 반대였으며 전이상태에서 1-나프틸 화합물의 peri-hydrogen 효과에 기인된 것으로 설명할 수 있었다. Winstein 그림표의 m값과 Kivinen 그림표의 n값에 의하면 물-에탄올 혼합용매속에서의 두 염화 나프탈렌술포닐의 가용매 분해 치환반응은 $S_N2$형 반응과정으로 진행된다고 결론지웠다. Kinetic studies on solvolytic reactions of 1-and 2-naphthalene sulfonyl chlorides in ethanol-water mixtures have been carried out by means of conductometry at several temperatures. The rate constant for 2-naphthyl compound was larger than that for 1-naphthyl compound. This was contrary to the prediction of MO theory and could be rationalized as due to the peri-hydrogen effect in the transition state for 1-naphthyl compound. Based on m values of Winstein plots and n values of Kivinen pacolots it was concluded that the solvolytic displacement of the two naphthalene sulfonyl chlorides in ethanol-water mixtures proceed via $S_N2$ process.

        • SCOPUSKCI등재
        • KCI등재

          Optimal dimension design of a hatch cover for lightening a bulk carrier

          엄태섭,노명일 대한조선학회 2015 International Journal of Naval Architecture and Oc Vol.7 No.2

          According to the increase of the operating cost and material cost of a ship due to the change of international oil price, a demand for the lightening of the ship weight is being made from various parties such as shipping companies, ship owners, and shipyards. To satisfy such demand, many studies for a light ship are being made. As one of them, an optimal design method of an existing hull structure, that is, a method for lightening the ship weight based on the optimization technique was proposed in this study. For this, we selected a hatch cover of a bulk carrier as an optimization target and formulated an optimization problem in order to determine optimal principal dimensions of the hatch cover for lightening the bulk carrier. Some dimensions representing the shape of the hatch cover were selected as design variables and some design considerations related to the maximum stress, maximum deflection, and geometry of the hatch cover were selected as constraints. In addition, the minimization of the weight of the hatch cover was selected as an objective function. To solve this optimization problem, we developed an optimization program based on the Sequential Quadratic Programming (SQP) using C++ programming language. To evaluate the applicability of the developed program, it was applied to a problem for finding optimal principal dimensions of the hatch cover of a deadweight 180,000 ton bulk carrier. The result shows that the developed program can decrease the hatch cover’s weight by about 8.5%. Thus, this study will be able to contribute to make energy saving and environment-friendly ship in shipyard.

        • 學校實驗室廢水에 대한 調査 硏究 : 하단캠퍼스를 中心으로 Around the Hadan Compus of Dong-A University

          엄태섭,박유미,이종팔 동아대학교 환경문제연구소 1986 硏究報告 Vol.9 No.1

          The monthly estimation of the waste water components effluenced from the laboratories of Colleges in Dong-A University has been determined and the laboratory waste water and the sewage in university also analyzed to survey and study for the present situation and disposal treatment plan to get as the basic data It has been come to a conclusion as follows 1) The waste matter of laboratories in University has composed the organic chemical waste of 48% and the inorganic chemical waste of 52%. The large amount of effluence are Cu of 35% Cr of 27% in inorganic chemical waste and there are a little bit amount of Pb As. Fe CN etc. 2) The pollution level of metal ions for each college laboratory has shown the highest in the college of Natural Sciences and October in each month. This view seems that the frequency in use of laboratory are the highest and the laboratories have many students in laboratory of general physics. laboratory of general chemistry and laboratory of general biology. 3) From the analysis and determination the sewage in university has shown the average pH 7.2 as to be neutrality and COD. BOD and the contamination level have shown lower the maximum permissible limit. 4) The components of waste water of college laboratories have diversity. It seems to be proper that the blanket treatment system which recollect separately to treat each component different from the industrial waste disposal treatment because there are many the effluent outlets.

        • β-nitrostyrene에 대한 n-propyl과 laurylmercaptan 의 親核性 添加反應 速度常數의 測定

          嚴泰燮 東亞大學校 1968 東亞論叢 Vol.5 No.-

          The rate-constants for the nucleophilic addition reaction of n-propylmercaptan and of laurylmercaptan to 3. 4-methylenedioxy-β-nitrostyrene, respectively, for various pH at 25℃ were observed by spectrophotometry. Those of the pseudo-first order reaction for n-propylmercaptan in acidic media and those of the second-order reaction for laurylmercaptan over the pH range o to 11 were observed. From the results, it was found that there is the simple proportionality between the rate-constants and pH above the pH;4, but there is no influence of pH on the reaction below the pH:2 for n-propylmercaptan. Therefore, it is shown that kinetics and mechanism of the reaction are obviously different at the both high and low pH range in acidic media. On the other hand, the change of rate-constants of laurylmercaptan accompanying change of pH is too complicated to interpret the mechanism of the reaction. To study for the quantitative analysis of its mechanism, there will be required more informations for the reaction of various nucleophiles to β-nitrostyrene.

        • 염화나프탈렌술포닐의 親核性 置換反應에 미치는 溶媒效果

          嚴泰燮 東亞大學校 1981 東亞論叢 Vol.18 No.1

          The solvolysis of 1-naphthalene and 2-naphthalene sulfonyl chloride have been studied for the solvent effect on rates in various solvant mixtures: acetonitrile-dimethyl sulfoxide(DMSO), acetone-DMSO, dioxane-DMSO, methanol-DMSO, ethanol-DMSO. Transition state variation caused by the changes solvent composition of the solvent mixture has shown the More O'Ferrall plots. The results of nucleophilic displacement reaction are preceded by a dissociative S?2 mechanism in higher aprotic solvent and DMSO solvent mixture and in higher dielectric constant aprotic solvent and DMSO mixtures. Structure-reactivity interaction on nucloephilic displacement reaction of naphthalene sulfonyl chlorides with substituded anilines has been observed associative S?2 mechanism. And it has been shown that DMSO solvent is a very strong uncleophile in each solvent mixture.

        • 염화나프탈렌 술포닐의 친핵성 치환반응에 관한 연구

          엄태섭 東亞大學校 1978 東亞論叢 Vol.15 No.2

          The kinetics for solvoysis of 1-naphthalenesulfonyl chloride and 2-naphthalenesulfonyl chloride in ethanol-water and acetone-water mixtures have been studied. The nucleophilic substitution reactions of para-substit-uted anilines with the two substrates have been investigated by means of conductometry. The reactivity and mechanism fo solvolysis have been discussed in terms of solvent composition and activation parameters, but bond-breaking increased with the increase of water content. The reaction rate of 2-naphyhyl compound in solvent was faster than that of 1-naphthyl compound due to the peri-hydrogen effect in the transition state and the ground state stabilization effect. Pseudo-first order rate constants Kobs were determined for the reactions of naphthalenesulfonyl chlorides with para-substituted anilines. The second order rate constants K₂ and third order catalytic constants k₃ were then determined from kobs. For 1-naphthyl compound in this reaction peri-hydrogen effect was also observed. The large Bronsted coefficient βand large negative slope ρfor the Hammett plots were obtained. These results together with the unusually low valuses of activation paremeters were consistent with the SAN-elimination mechanism, but these could be equally well interpreted with the associative SN2 mechanism.

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