• Proceedings of the Materials Research Society of Korea Conference
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• 2003.03a
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• pp.61-61
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• 2003

CMP(Chemical Mechanical Polishing)는 VLSI의 제조공정에서 실리콘웨이퍼의 절연막내에 있는 토포그래피를 제어할 수 있는 광역 평탄화 기술이다. 또한 최근에는 실리콘웨이퍼의 나노토포그래피(Nanotopography)가 STI의 CMP 공정에서 연마 후 필름의 막 두께 변화에 많은 영향을 미치게 됨으로 중요한 요인으로 대두되고 있다. STI CMP에 사용되는 CeO$_2$ 슬러리에서 첨가되는 계면활성제의 농도에 따라서 나노토포그래피에 미치는 영향을 제어하는 것이 필수적 과제로 등장하고 있다. 본 연구에서는 STI CMP 공정에서 사용되는 CeO$_2$ 슬러리에서 계면활성제의 농도에 따른 나노토포그래피의 의존성에 대해서 연구하였다. 실험은 8 "단면연마 실리콘웨이퍼로 PETEOS 7000$\AA$이 증착 된 것을 사용하였으며, 연마 시간에 따른 나노토포그래피 의존성을 알아보기 위해 연마 깊이는 3000$\AA$으로 일정하게 맞췄다. 그리고 CMP 공정은 Strasbaugh 6EC를 사용하였으며, 패드는 IC1000/SUBA4(Rodel)이다. 그리고 연마시 적용된 압력은 4psi(Pounds per Square Inch), 헤드와 정반(table)의 회전속도는 각각 70rpm이다 슬러리는 A, B 모두 CeO$_2$ 슬러리로 입자크기가 다른 것을 사용하였고, 농도를 달리한 계면활성제가 첨가되었다. CMP 전 후 웨이퍼의 막 두께 측정은 Nanospec 180(Nanometrics)과 spectroscopic ellipsometer (MOSS-ES4G, SOPRA)가 사용되었다.

• Environmental Analysis Health and Toxicology
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• v.30
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• pp.6.1-6.7
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• 2015

Objectives This study aimed to estimate the effects of 4-nonylphenol (NP), a ubiquitously present surfactant in aquatic environments, on the anti-oxidant systems of the liver in the Far Eastern catfish Silurus asotus. Methods Changes in biochemical parameters involved in glutathione (GSH)-related and other anti-oxidant systems were analyzed following 4 weeks of 4-NP administration (0.1 and 1.0 mg/kg diet) via a formulated diet to catfish. Results 4-NP exposure induced an elevation in hepatic lipid peroxide levels and an accompanying decrease in reduced state GSH after 2 weeks, suggesting pro-oxidant effects of the chemical in catfish. This oxidative stress was associated with an inhibition of the GSH-utilizing enzyme glutathione peroxidase at the same time point. This inhibition was restored after 4 weeks. The activities of other anti-oxidant enzymes, i.e., glutathione reductase, superoxide dismutase and catalase were increased after 4 weeks. These enzyme increases occurred more strongly at the higher 4-NP concentration (1.0 mg/kg diet). Conclusions 4-NP given to catfish at 0.1 to 1.0 mg/kg diet, concentrations relevant to environmental levels, depletes the endogenous anti-oxidant molecule GSH and temporarily inhibits GSH-related anti-oxidant enzymes. Such declines in anti-oxidant capacity and elevated oxidative stress seem to be compensated eventually by subsequent activation of various anti-oxidant enzyme systems.

• Journal of the Korean Applied Science and Technology
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• v.7 no.2
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• pp.11-18
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• 1990

N-alkyl carboxy pyridinium chlorides such as N-lauryl carboxy-pyridinium chloride, N-myristyl carboxy pyridinium chloride, N-cetyl carboxy pyridinium chloride and N-stearyl carboxy pyridinium chloride were synthesized by the reaction of nicotinic acid and isonicotinic acid with long chain alkyl chlorides, and N-alkyl pyrinium carboxylates such as N-lauryl pyridinium carboxylate, N-myristyl pyridinium carboxylate. N-cetyl pyridinium carboxylate and N-stearyl pyridinium carboxylate were prepared from N-alkyl carboxy pyridinium chlorides. These reaction products could be separated by both column chromatogrphy, and paper chromatography, and there dissociation constants of N-alkyl pyridinium carboxylates were found to pKa $1.0{\times}10^{13}{\sim}6,31{\times}10^{14}$.

• Journal of Microbiology and Biotechnology
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• v.9 no.2
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• pp.191-195
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• 1999

Bioconversion of fumarate to succinate by Enterococcus sp. RKY1 was enhanced when Tween surfactant, organic solvent, and vegetable oil were added to the fermentation medium. The maximum amount of succinate produced was 80.4 g/l after a 24 h incubation when Tween 80 was added to the culture to a final concentration of 0.1 g/l. Triton X-l00 was observed to damage the enzymes and inhibit the formation of succinate. The addition of 10 ml/l acetone increased the production of succinate by 110%. Vegetable oils used were found to be effective for succinate production as well as for the cell growth. Similar productivity increases were obtained with corn oil and Tween 80 plus biotin with the total productivity being 3.6 g/l/h, and 3.5 g/l/h, respectively, which was approximately 25% greater than that of the control. Therefore, these results indicate that com oil can be considered the most appropriate agent for the production of succinate where succinic acid was primarily used in the production of food, medicine, and cosmetics.

• Culinary science and hospitality research
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• v.24 no.2
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• pp.119-127
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• 2018

The purpose of this study is to investigate the contamination level of micro plastics in Korean mackerel and to investigate the detection method of micro plastics in fish. This study analyzed the detection and composition of micro plastics using natural mackerel and wild mackerel. 30% hydrogen peroxide and surfactant were added to GF/C filter paper in order to detect micro plastics in the sea. If micro plastics are exposed to the ocean for a long time, accumulation of heavy metals in the water will make pollutant bioaccumulation more serious. Microscopic consequences The risk to human health of plastics has already been studied by many researchers and the risks to human health already caused by marine microorganisms and zooplankton are becoming clear. The conclusion of this study is that there is a difference between the length and height of the mackerel when it is cooked from the standpoint of food in terms of practical implications. The conclusion of this study is that the probability of micro-plastic-contaminated mackerel to reach and be consumed by end-consumers is low in academic implications. Residual contaminants adsorbed on micro plastics are absorbed by digestive organs and cause disruption, and further research on micro plastics is needed in the future.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.35 no.3
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• pp.171-177
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• 2009

This study described formation and dispersion of stable lamellar structure containing ceramide. To characterize of the lamellar structure containing ceramide, we used differential scanning calorimetry, x-ray diffraction, and FT-IR spectra, which enabled us to demonstrate that ceramide with appropriate amounts of lipid, oil and surfactant can assemble to form a stable lamellar-phase. These approaches to use ceramide offers useful means to fabricate a variety of biocompatible emulsion and liposome, which enlarge their applicability in the fields of drug delivery, dermatology and cosmetics.

• Korean Journal of Materials Research
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• v.27 no.5
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• pp.270-275
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• 2017

Inorganic phosphors based on $ZrO_2:Eu^{3+}$ nanoparticles were synthesized by a salt-assisted ultrasonic spray pyrolysis process that is suitable for industrially-scalable production because of its continuous nature and because it does not require expensive precursors, long reaction time, physical templates or surfactant. This facile process results in the formation of tiny, highly crystalline spherical nanoparticles without hard agglomeration. The powder X-ray diffraction patterns of the $ZrO_2:Eu^{3+}$ (1-20 mol%) confirmed the body centered tetragonal phase. The average particle size, estimated from the Scherrer equation and from TEM images, was found to be approximately 11 nm. Photoluminescence (PL) emission was recorded under 266 nm excitation and shows an intense emission peak at 607 nm, along with other emission peaks at 580, 592 and 632 nm which are indicated in red.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.587-587
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• 2012

Supercapacitors, which can deliver significant energy with high power density, have attracted a lot of attention due to their potential application in energy storage. Among various oxide materials, sodium vanadate has been recognized as one of the most promising electrode materials because of high electrical conductivity. In addition, larger layer spacing of ${\beta}$-Na0.33V2O5 compared to V2O5 makes easier Li+ insertion. Moreover, ${\beta}$-Na0.33V2O5 has a tunnel like structure along b axis with 3 kinds of V site allowing it to enhance the ion intercalation by introducing three different intercalation sites along the tunnel. The tunnel can act as a fast diffusion path for ion diffusion, which can improve the overall charge storage kinetics. In this study, high quality single crystalline sodium vanadate (${\beta}$-Na0.33V2O5) nanowires were grown directly on Pt coated $SiO_2$ substrate by a facile chemical solution deposition method without employing catalyst, surfactant or carrier gas. The results show that great enhancement in capacitance was observed compared with previous reports.

• Journal of Powder Materials
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• v.24 no.4
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• pp.315-320
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• 2017

There has been much interest in recycling electronic wastes in order to mitigate environmental problems and to recover the large amount of constituent metals. Silver recovery from electronic waste is extensively studied because of environmental and economic benefits and the use of silver in fabricating nanodevices. Hydrometallurgical processing is often used for silver recovery because it has the advantages of low cost and ease of control. Research on synthesis recovered silver into nanoparticles is needed for application to transistors and solar cells. In this study, silver is selectively recovered from the by-product of electrodes. Silver precursors are prepared using the dissolution characteristics of the leaching solution. In the liquid reduction process, silver nanoparticles are synthesized under various surfactant conditions and then analyzed. The purity of the recovered silver is 99.24%, and the average particle size of the silver nanoparticles is 68 nm.

• Applied Chemistry for Engineering
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• v.17 no.5
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• pp.443-450
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• 2006

Micelles have been used in many applications. In these applications it is of prime importance to know how the critical micelle concentration (CMC), above which the micelles are formed, depends on temperature. Up to date polynomial functions of temperature have been used to describe temperature dependence of CMC. In this article it is shown that such polynomials are inadequate tools to express thermal behavior of CMC. Hence, new equations of CMC(T) have been derived on the basis of rigorous thermodynamic equations and experimental observations on CMCs. The new equations fit CMC data excellently, and further they lead to a power law for the CMC. The exponent of the power-law expression is 2 irrespective of surfactant systems, which points to the generality of newly found equations.