• 한국식품영양과학회지
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• 제23권5호
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• pp.867-878
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• 1994

A general overview of the lipid peroxidation and its nutritional significance are presented ,with emphasis on the reaction mechaisms, peroxidized products, further interaction and nutritional/biological deterioration in a series of oxidative process. Overall mechanism with various factors and elements for initiation , propagation and termination of free radical reaction is reviewed and the primary /secondary products of peroxidized lipids are defined. Since these products are potentially reactive substances that can cause deterioration of proteins /amino acids and vitamins (carotene, tocopherols and ascorbic acid etc), mechanism and actual damages of their deterioration in some foods and biological models are outlined. Especially , chemical changes caused by interaction of peroxidized products (related hydroperoxides, radicals and malonaldehye etc) and protein are emphasized here. And also, the detailed mechanisms on radical scavenging of the these vitamins which are the most prominent natural antioxidants are presented . Additionally , the possible roles of peroxidicaed lipids and their secondary products in the process of aging an carcinogenesis are briefly discussed . However, it is important to not that more detailed and integrated studies on the reaction kinetics, energetics of peroxidation, their decomposed products , biochemical interaction potential damaging/aging / carcinogenic effects, protection from their oxidative spoilage and novel antioxidants in food and heterogeneous biological systems will be essential in order to assessing the implication of lipid peroxidation to human nutrition and health.

• 한국연소학회지
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• 제9권4호
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• pp.28-34
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• 2004

Numerical simulations of freely propagating flames burning $H_2/HCl/Air$ Air mixtures were performed at atmospheric pressure in order to understand the effect of hydrogen chloride on flame structures. The chemical and physical effects of hydrogen chloride on flame structures were observed. A chemical kinetic mechanism was developed, which involved 26 gas-phase species and 198 forward elementary reactions. Under several equivalence ratios the flame speeds were calculated and compared with those obtained from the experiments, the results of which were in good agreement. As hydrogen chloride as additive was added into $H_2/Air$ flame, the flame speed, radical concentration and NO production rate were decreased. The chemical effect of hydrogen chloride caused the reduction of radical concentration, and then the decrease of the net rate of NO production. It was found that the influence in the reduction of $EI_{NO}$ with the addition of hydrogen chloride was attributed more due to the chemical effect than the physical effect.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2000년도 추계학술대회논문집
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• pp.40-44
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• 2000

In this paper, since the research on the etching of SrBi$_2$Ta$_2$O$_{9}$ (SBT) thin film was few (specially Cl$_2$-base ), we had studied the surface reaction of SBT thin films using the OES in high density plasma etching as a function of rf power, dc bias voltage, and Cl$_2$/(C1$_2$+Ar) gas mixing ratio. It had been found that the etch rate of SBT thin films appeared to be more affected by the physical sputtering between Ar ions and surface of the SBT compared to the chemical reaction in our previous papers$^{1.2}$ . The change of Cl radical density that is measured by the OES as a function of gas combination showed the change of the etch rate of SBT thin films. Therefore, the chemical reactions between Cl radical in plasma and components of the SBT enhance to increase the etch rates of SBT thin films and these results were confirmed by XPS analysis.

• 공업화학
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• 제16권1호
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• pp.9-14
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• 2005

펜톤 반응(2가 철+과산화수소)은 오늘날 환경기술분야에서 응용 가능성이 높아 큰 주목을 받고 있으며, 그 원리를 응용한 새로운 기술들이 활발하게 연구되고 있다. 하지만 다양한 응용 연구에도 불구하고, 그 화학반응의 상세한 메커니즘은 아직도 명확히 밝혀지지 않았으며 연구자들 사이에 여전히 논쟁이 진행되고 있다. 지금까지 학계에서는 펜톤 반응에서 생성되는 (산화)반응성이 큰 화학종으로 수산화 라디칼 또는 고가 산화철 복합체가 제시되어 왔는데, 본고에서는 이러한 논의들의 핵심적인 내용을 비판적으로 정리, 고찰하고자 하였다.

• 전기화학회지
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• 제10권3호
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• pp.159-168
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• 2007

An electrochemical study related to the redox characteristics of Ethyl-3-acetyl-6-methyl-1, 4-diphenyl-4, 3a-dihydro-1, 3, 4-triazolino[3, 4-a] pyrimidine-5-carboxylate ester and its derivatives (1a-f) and (2a-e) in nonaqueous solvents such as 1, 2-dichloroethane (DCE), dichloromethane (DCM), acetonitrile (AN), dimethylsulphoxide (DMSO) and tetrahydrofurane (THF) using $0.1\;mol\;dm^{-3}$ tetrabutylammonium perchlorate (TBAP) as a supporting electrolyte at platinum, glassy carbon and gold electrodes, has been performed using cyclic voltammetry (CV). Controlled potential electrolysis (CPE) is also carried out to elucidate the course of different electrochemical reactions through the separation and identification of the intermediates and final electrolysis products. The redox mechanism is suggested and proved. It was found that all the investigated compounds in all solvents are oxidized in a single irreversible one electron donating process following the well known pattern of the EC-mechanism to give a dimer. On the other hand, these compounds are reduced in a single irreversible one electron step to form the anion radical, which is basic enough to proton from the media forming the radical which undergoes tautomerization and then dimerization processes to give also another bis-compound through N-N linkage formation.

• Bulletin of the Korean Chemical Society
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• 제32권3호
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• pp.964-972
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• 2011

This work investigated the difference between $Fe^{2+}$ autoxidation-induced and Fenton-type cleavage of pBR322 plasmid DNA. $^{\cdot}OH$ generation reactions in the absence and presence of $H_2O_2$ under various conditions were also investigated. Although both the $Fe^{2+}$ autoxidation and Fenton-type reactions showed DNA cleavage and $^{\cdot}OH$ generation, there were significant differences in their efficiencies and reaction rates. The rate and efficiency of the cleavage reaction were higher in the absence of 1.0 mM of $H_2O_2$ than in its presence in 20 mM phosphate buffer. In contrast, the $^{\cdot}OH$ generation reaction was more prominent in the presence of $H_2O_2$ and showed a pH-independent, fast initial reaction rate, but the rate was decreased in the absence of $H_2O_2$ at across the entire tested pH range. Studies using radical scavengers on DNA cleavage and $^{\cdot}OH$ generation reactions in both the absence and presence of $H_2O_2$ confirmed that both reactions spontaneously involved the active oxygen species $^{\cdot}OH$, ${O_2}^{\cdot-}$, $^1O_2$ and $H_2O_2$, indicating that a similar process may participate in both reactions. Based on the above observations, a new mechanism for the $Fe^{2+}$ autoxidation-induced DNA cleavage reaction is proposed.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 추계학술대회 논문집
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• pp.40-44
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• 2000

In this paper, since the research on the etching of SrBi$_2$Ta$_2$O$_{9}$ (SBT) thin film was few (specially Cl$_2$-base ), we had studied the surface reaction of SBT thin films using the OES in high density plasma etching as a function of rf power, dc bias voltage, and Cl$_2$(Cl$_2$+Ar) gas mixing ratio. It had been found that the etch rate of SBT thin films appeared to be more affected by the physical sputtering between Ar ions and surface of the SBT compared to the chemical reaction in our previous papers$^{1.2}$ . The change of Cl radical density that is measured by the OES as a function of gas combination showed the change of the etch rate of SBT thin films. Therefore, the chemical reactions between Cl radical in plasma and components of the SBT enhance to increase the etch rates of SBT thin films and these results were confirmed by XPS analysis.

• 대한환경공학회지
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• 제22권5호
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• pp.869-877
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• 2000

Phenanthrene과 benzo[a]pyrene으로 오염된 토양을 슬러리상에서 오존처리시 반응메커니즘을 조사하였다. 토양내 오존주입시 OH-radical의 생성과 반응에 있어서 유 무기물의 영향을 알아보기 위하여 단순화된 토양매질로써 baked sand(BS), sand(S), glass beads(GB)를 택하여 실험한 결과 제거속도가 BS>S>GB 순으로 나타났다. Radical scavenger 실험을 통하여 OH-radical의 발생경향을 살펴보았는데, BS의 경우 OH-radical의 생성으로 오존과의 직접반응과 더불어 제거효율이 22% 상승됨을 알 수 있었다. Humic acid의 초기농도를 0~5 ppm으로 증가시킴에 따라 반응속도상수(psuedo first-order rate constant: $k_o$)가 $1.37{\times}10^{-2}s^{-1}$에서 $0.53{\times}10^{-2}s^{-1}$으로 감소하였으며, S매질상에서 PAHs의 초기농도 10mg-PAHs/kg-soil의 80%를 제거하는데 소모되는 오존 주입량은 phenanthrene의 경우 $67.2mg-O_3/kg-soil$였고, benzo[a]pyrene의 경우 $48.0mg-O_3/kg-soil$로 산정되었다.

• 한국연소학회지
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• 제13권1호
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• pp.10-16
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• 2008

Numerical simulations of freely propagating premixed flames burning mixtures of methane and chlorinated hydrocarbons in fuel are performed at atmospheric pressure in order to understand the effect of chlorinated hydrocarbons on the formation of nitrogen oxide. A detailed chemical reaction mechanism is used, the adopted scheme involving 89 gas-phase species and 1017 elementary forward reaction steps. Chlorine atoms available from chlorinated hydrocarbons inhibit the formation of nitrogen oxides by lowering the concentration of radical species. The reduction of NO emission index calculated with thermal or prompt NO mechanism is not linear and is probably related to the saturation effect as $CH_3Cl$ addition is increased, In the formation or consumption of nitrogen oxide, the $NO_2$ and NOCl reactions play an important role in lean flames while the HNO reactions do in rich flames. The molar ratio of Cl to H in fuel has an effect on the magnitude of NO emission index.

• 대한전기학회논문지
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• 제36권1호
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• pp.29-35
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• 1987

TPolystyrene thin films are prepared by glow discharge of sytrene monomer vapor th establish the growth mechanism of organic thin films by the plasma polymerization. As the discharge parameters, discharge current(5mA-20mA), frequency (10kHz-50kHz, 13.56MHz), gaspressure (0.2torr-1.5torr), and discharge time(2min-12min)are adopted. Plasma-polymerized filmsof styrene vapor are identified as polystyrene by IR spectra. The thickness of plasma-polymerized films increases with gas pressure, frequency and discharge current in the region of the low frequency and below the allowed gas pressure where the polymerization occurs. It is suggested that the growth mechanism can be explained by ionic reaction in d.c. and low frequency region, and by radical reaction in high frequency region.