• Title/Summary/Keyword: Chemical response

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Optimization of Benzene Synthesis for Radicarbon Dating by Response Surface Method

  • 나경임;강형태;김승원;최상원;김윤섭;김순옥
    • Bulletin of the Korean Chemical Society
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    • v.18 no.7
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    • pp.703-706
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    • 1997
  • Response surface method was applied to the predicting optimum conditions of benzene synthesis for radiocarbon dating. The weight of carbon dioxide, the temperature of lithium container for producing acetylene and the activation temperature of catalyst which was used for the cyclization of acetylene to benzene were used as experimental factors. The yields of benzene synthesis were measured from twelve experiments which were carried out under various experimental conditions. The polynomial equation was obtained by using three experimental factors and yields. The validity of polynomial equation was confirmed by comparing the calculated yields with the experimental ones.

Mechanically Immobilized Copper Hexacyanoferrate Modified Electrode for Electrocatalysis Amperometric Determination of Glutathione

  • D. Davi Shankaran;S. Sriman Narayanan
    • Bulletin of the Korean Chemical Society
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    • v.22 no.8
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    • pp.816-820
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    • 2001
  • A new copper hexacyanoferrate modified electrode was constructed by mechanical immobilization. The modified electrode was characterised by cyclic voltammetric experiments. Electrocatalytic oxidation of glutathione was effective at the modified electrode at a significantly reduced overpotential and at broader pH range. The modified electrode shows a stable and linear response in the concentration range of 9 ${\times}$10-5 to 9.9 ${\times}$10-4M with a correlation coefficient of 0.9995. The modified electrode exhibits excellent stability, reproducibility and rapid response and can be used in flow injection analysis for the determination of glutathione.

Development and research of gas sensor for monitoring sulfur compounds (황화물 측정용 가스센서의 연구개발)

  • Kim, Ki-Young;Kim, Jong-Min;Ham, Young-Hwan;Chang, Yong-Keun;Kim, Jong-Deuk;Chang, Sang-Mok
    • Journal of Sensor Science and Technology
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    • v.3 no.2
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    • pp.33-39
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    • 1994
  • A quartz crystal microbalance (QCM) sensor system for the detection of odorants, especially environmental pollutant, has been constructed by depositing various phospholipids, activated carbon and lead compound pigment onto the surface of the QCM. The characteristics of a QCM operating at 9 MHz deposited with phosphatidyl- choline were analysed. An explanation is given for different odorant affinities based on the monolayer properties of phospholipids. The identification of odorants is discussed in terms of a comparison of their normalized resonant frequency shift patterns and relative response intensities calculated from the response areas. Applying the lead compound pigment coated QCM, it was possible to detect sulfur compound specifically. Using a number of different lipid-coated QCMs, odorants could be identified by comparing the response patterns.

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Development of a Risk Assessment Program for Chemical Terrorism (화학적 테러에 대한 위험성 평가 프로그램 개발)

  • Lee, Younghee;Kim, Eunyong;Kim, Jinkyung;Moon, Il
    • Journal of Korean Society of societal Security
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    • v.1 no.1
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    • pp.63-67
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    • 2008
  • This study focuses on assessing the security ri sk or the terrorism in chemical process industries. This research modifies conventional method for assessing the terrorism risk. The risk assessment method is developed and it is implemented as software to analyze the possibility of terrorism and sabotage. This program includes five steps; asset characterization, threat assessment, vulnerability analysis, risk assessment and new countermeasures. It is a systematic, risk based approach in which risk is a function of the severity of consequences of an undesired event, the likelihood of adversary attack, and the likelihood of adversary success in causing the undesired event. The reliability of the program is verified using a dock zone case. The case dock zone includes a storage farm, a manufacturing plant, an electrical supply utility, a hydrotreater unit, many containers, and administration buildings. This study represents chemical terrorism response technology, the prevention plan, and new countermeasure to mitigate by using risk assessment methods in the chemical industry and public sector. This study suggests an effective approach to the chemical terrorism response management.

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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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Production of Tween 80-inducing Esterase by Acinetobacter sp. B1 Using Response Surface Methodology

  • Ma, Peiyu;Li, Yuqi;Miao, Chensi;Sun, Yunpeng;Liu, Chunhui;Li, Huijuan
    • Microbiology and Biotechnology Letters
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    • v.47 no.1
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    • pp.87-95
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    • 2019
  • Esterase produced by Acinetobacter sp. B1 (strain B1) was optimized by means of one-variable-at-a-time and response surface methodologies. Results of the one-variable-at-a-time experiment showed that Tween 80 significantly increased esterase production of strain B1. The addition of Tween 80 to the culture medium increased the biomass and esterase activity of strain B1, stimulated content of total extracellular protein, and enhanced the oleic acid (C18:1) composition in the cell membrane of strain B1. The influence of eight culture variables on esterase production was evaluated by Plackett-Burman design. Results showed that Tween 80, pH, and $K_2HPO_4$ significantly affected the esterase production of strain B1. Tween 80, pH, and $K_2HPO_4$ were further optimized by central composite design. Under the optimized conditions (w/v, soluble starch 2.5%, tryptone 1.5%, Tween 80 0.8%, $K_2HPO_4$ 0.5%, NaCl 0.5%, pH 8.0, inoculum size 1%, and inoculum age 24 h), the maximum esterase activity of strain B1 was 152.13 U/ml, which was 10-fold higher than that of non-optimization after 36 h cultivation.