• Title/Summary/Keyword: Chemical effect

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A Study on the Gravitational Effect Influencing Retention Behavior of Polymer in Thermal Field Flow Fractionation (열장 흐름 분획법에서 중력효과에 의한 고분자의 머무름 거동에 관한 연구)

  • Ryoo, Ki-Seok;Song, Byoung-Su;Park, Jong-Won;Min, Byoung-Ryul
    • Journal of the Korean Chemical Society
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    • v.39 no.11
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    • pp.848-855
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    • 1995
  • The influence of gravitational effect on the retention behaviors of polystyrene (PS) and polymethylmethacrylate (PMMA) in flat type thermal field flow fractionation (Thermal FFF) was studied. In the case of downward flow of mobile phase, the gravitational effect acting in the same direction of mobile phase flow increases as the angle of the system from the horizontal line (0˚to 60˚) increases. The decreasement of retention time of PS & PMMA was found. Also, the increasement of dimensionless λ values was found. And the difference in the retention time of PS & PMMA having different molecular weight decreases and also the resolution decreases. In the case of upward flow of mobile phase, the gravitational effect acting in the opposite direction of mobile phase flow increases as the angle of the system from the horizontal line (0˚to 60˚) increases. The increasement of retention time of PS & PMMA was found. Also, the decreasement of dimensionless λ values was found. And the difference in the retention time of PS & PMMA having different molecular weight increases and also the resolution increases.

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A Study on Product Liability Response System of Chemical Products by Using Failure Mode and Effect Analysis (FMEA기법을 이용한 화학제품의 PL 대응체계 연구)

  • Ko J. W.;Yoo J. H.;Kim D. H
    • Journal of the Korean Institute of Gas
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    • v.7 no.4 s.21
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    • pp.30-35
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    • 2003
  • Product liability(PL) law imposes the liability on manufacturer or wholesaler when the product defects cause harm to consumers of the products or any other parties in their lives, bodies, or properties. In Korea, the law of product liability was enforced in July 2002. In this study the Product Liability Response System of chemical products was developed by using Failure Mode and Effect Analysis(FMEA). For a case study peformed for N,N-Dimethylethylamine. First, product information was gathered through Material Safety Data Sheet(MSDS)and which considered as an instruction manual of chemical product. And an effect caused by product defects is analyzed by FMEA to get Risk Priority Number(RPN) which is calculated by multiplying of severity, occurrence, and detection of the defects. Then hazard was estimated quantitatively by RPN.

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Effect of $CO_2$ Addition on Flame Structure and NOx Formation of $CH_4-Air$ Counterflow Diffusion Flames ($CO_2$ 첨가가 $CH_4$-공기 대향류 확산화염의 구조 및 NOx 생성에 미치는 영향)

  • Lee, S.R.;Han, J.W.;Lee, C.E.
    • Journal of the Korean Society of Combustion
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    • v.4 no.2
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    • pp.97-108
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    • 1999
  • This numerical study was to investigate the effect of $CO_2$ addition on the structures and NOx formation characteristics in $CH_4$ counterflow diffusion flame. The importance of radiation effect was identified and $CO_2$ addition effect was investigated in terms of thermal and chemical reaction effect. Also the causes of NOx reduction were clarified by separation method of each formation mechanisms. The results were as follows : The radiation effect was intensified by $CO_2$ addition. Thermal effect mainly contributed to the changes in flame structure and the amount of NO formation but the chemical reaction effect also cannot be neglected. The reduction of thermal NO was dominant with respect to reduction rate, but that of prompt NO was dominant with respect to total amount.

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Improvement of low temperature thermal stability on PVC (PVC의 저온 열안정성 향상에 관한 연구)

  • Chung, Kwang-Bo;Jeon, In-Ki;Ahn, Sung-Hwan
    • Journal of the Korean Applied Science and Technology
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    • v.26 no.4
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    • pp.440-450
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    • 2009
  • Metal(Zinc) soap and mixed metal(Zn/Ba) soap were synthesized with good structures and characterized by IR and H-NMR. The H-NMR spectrums of the synthesized soaps were in very good accordance with the structures proposed by earlier workers. The mixed metal soaps with various costabilizers(acid or metal content effect), which added in order to investigate the thermal stabilization effect at low and high temperature, were investigated the thermal stabilization effect. The temperature effect is relation to the metal content effect than acid effect. In case of mixed metal soap, the high thermal stabilization effect improved with increasing Barium content. As the Zinc content increase the low temperature thermal stabilization effect improved, but the high temperature thermal stabilization effect showed an opposite tendency.

Linear Free Energy Relationship on the Chemical Shift of Imidoyl Proton in N-benzylideneaniline Derivatives by PMR Spectrometry (核磁氣 共鳴分光法에 義한 N-Benzylideneaniline 誘導體중 Imidoyl Proton 의 Chemical Shift 에 미치는 自由에너지 關係)

  • Nack Do Sung;Cheon Kyu Park;Moon kyu Park;Ki Sung Kwon;Kim, Tae Rin
    • Journal of the Korean Chemical Society
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    • v.29 no.3
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    • pp.277-282
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    • 1985
  • The effects of linear free energy relationship (LFER) on the imidoyl proton (H${\alpha}$)-substituent chemical shift (SCS) in case of varying para-substituted C-phenyl group in N-benzylideneaniline derivatives were studied. The H${\alpha}$-SCS values and LFER parameters such as ${\sigma}$,${\sigma}^+$, ${\sigma}_I$,${\sigma}_R, F and R were applied to the Hammett, Okamoto-Brown, and Taft, Swain-Lupton's dual substituents parameter (DSP) equations. The results were: (1) the blending coefficient values, ${\lambda}$ = 2.8∼3.2, it's means that the resonance effect (R) was larger than inductive effect (I) and field effect (F), and (2) the values of percent resonance and percent field effects were %R = 66.6 and %F = 33.4, respectively, yielding the ratio of resonance effect (R) to field effect (F) of 2 : 1.

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Spray coating of electrochemically exfoliated graphene/conducting polymer hybrid electrode for organic field effect transistor

  • Kim, Youn;Kwon, Yeon Ju;Hong, Jin-Yong;Park, Minwoo;Lee, Cheol Jin;Lee, Jea Uk
    • Journal of Industrial and Engineering Chemistry
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    • v.68
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    • pp.399-405
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    • 2018
  • We report the fabrication of organic field-effect transistors (OFETs) via spray coating of electrochemically exfoliated graphene (EEG) and conducting polymer hybrid as electrodes. To reduce the roughness and sheet resistance of the EEG electrodes, subsequent coating of conducting polymer (poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS)) and acid treatment was performed. After that, active channel layer was developed by spin coating of semiconducting poly(3-hexylthiophene) on the hybrid electrodes to define the bottom gate bottom contact configuration. The OFET devices with the EEG/PEDOT:PSS hybrid electrodes showed a reasonable electrical performances (field effect mobility = $0.15cm^2V^{-1}\;s^{-1}$, on/off current ratio = $10^2$, and threshold voltage = -1.57V). Furthermore, the flexible OFET devices based on the Polydimethlsiloxane (PDMS) substrate and ion gel dielectric layer exhibited higher electrical performances (field effect mobility = $6.32cm^2V^{-1}\;s^{-1}$, on/off current ratio = $10^3$, and threshold voltage = -1.06V) and excellent electrical stability until 1000 cycles of bending test, which means that the hybrid electrode is applicable to various organic electronic devices, such as flexible OFETs, supercapacitors, organic sensors, and actuators.

Dynamics Transition of Electroconvective Instability Depending on Confinement Effect (공간 제약 효과에 따른 전기와류 불안정성의 동역학 전이)

  • Lee, Seungha;Hyun, Cheol Heon;Lee, Hyomin
    • Korean Chemical Engineering Research
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    • v.59 no.4
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    • pp.626-631
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    • 2021
  • One of the nonlinear electrokinetic phenomena around ion exchange membrane is electroconvective instability which can be found in various electrokinetic applications such as electrodialysis, electrochemical battery, microfluidic analysis platform, etc. Such instability acts as a positive transport mechanism for the electrodialysis via amplifying mass transport rate. On the other hands, in the electrochemical battery and the microfluidic applications, the instability provokes unwanted mass transport. In this research, to control the electroconvective instability, the onset of the instability was analyzed as a function of confinement effect as well as applied voltage. As a result, we figured out that the dynamic behavior of electroconvective instability transited as a sequence of stable regime - static regime - chaotic regime depending on the applied voltage and confinement effect. Furthermore, stability curves about the dynamic transition were numerically determined as well. Conclusively, the confinement effect on electroconvective instability can be applied for effective means to control the electrokinetic chaos.

Effect of Decyl Alcohol EC on Tobacco Sucker Control (데실알콜유제의 담배 곁순억제호과)

  • 김기황;정훈채;김용연
    • Journal of the Korean Society of Tobacco Science
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    • v.26 no.1
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    • pp.7-12
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    • 2004
  • Effect of Decyl Alcohol Emulsifiable Concentrate on sucker control and phytotoxicity to tobacco plants were tested on flue-cured tobacco and burley tobacco. There were no significant differences of sucker inhibition effect between Decyl Alcohol EC and Choline Salt of Maleic Hydrazide Soluble Concentrate(control chemical). Tobacco plants applied with Decyl Alcohol EC showed no visible symptoms of phytotoxicity and no significant differences of number of leaves, leaf length, leaf width, and stalkt height. Yields increased considerably with no difference from ones of plants treated with control chemical.

Effect of Additives on Gamma Radiolysis of Methanol (메탄올의 감마선 분해에 대한 첨가물의 영향)

  • Choi, Sang-Up
    • Journal of the Korean Chemical Society
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    • v.14 no.3
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    • pp.237-242
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    • 1970
  • Effect of Added 1-hexene on the yield of hydrogen produced from Co-60 gamma radiolysis of methanol was investigated at room temperature. The results indicated that the yield of hydrogen decreased rapidly with increasing 1-hexene concentrations. Effect of added methyl borate on the radiolysis of methanol was also studied in the presence of oxygen. The results revealved that methyl borate acted as a less effective scavenger than oxygen towards the precursors of the radiolysis products. Experimental data previously obtained on the systems with oxygen added were treated more quantitatively to re-examine mechanism of the radiolysis of methanol in detail.

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Theoretical Studies on the Potential Energy Profiles for Proton Transfer Reaction in Formamide Dimer

  • Young Shik Kong;Mu Shik Jhon
    • Bulletin of the Korean Chemical Society
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    • v.10 no.6
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    • pp.488-491
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    • 1989
  • Theoretical studies on the proton transfer reaction in a formamide dimer have been done by Ab initio SCF calculation. In this study, we have shown several effects on the potential energy profile of the proton transfer in a formamide dimer, such as the effect of a basis set, the effect of a geometry optimization, and the effect of a distance between proton-donor and proton-acceptor.