• 청정기술
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• 제2권1호
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• pp.96-108
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• 1996

질산과 불산의 혼산용액을 사용하는 스테인레스 산세 공정에서 많은 $NO_x$가 발생하고 이로 인한 주위환경의 피해가 우려되어 왔다. 본 연구는 이미 생성된 $NO_x$를 제거하는 기존의 환경공학 연구와 달리, 청정기술 개발의 일환으로 기존 산세 공정을 일부 변경하여 $NO_x$ 생성을 저감하기 위한 연구이다. 연구내용은 크게 둘로 나누어지는데, 첫째로 산세 공정의 다양한 공정 변수가 $NO_x$ 생성에 어떻게 영향을 주는 가를 파악하였고 둘째로 $NO_x$ 생성 억제제인 과산화수소가 $NO_x$ 발생량에 미치는 영향을 조사하였다. 중요 결과로는 산세 공정에서 $NO_x$ 생성에 영향을 미치는 주요 산세공정 변수는 불산 농도, 반응 온도이며 $NO_x$ 발생의 원인 물질인 질산 농도의 영향은 불산 농도에 비하여 크지 않다. 합성 혼산의 경우 산세를 하지 않는 동안에도 $NO_x$를 발생시키나 그 양은 무시할 정도이다. 그러나, 산세 현장의 산세 용액은 산세를 하지 않는 상태에서도 $NO_x$ 발생은 크다. 산세 공정에서 과산화수소 첨가에 따른 $NO_x$ 생성의 저감은 매우 효과적이어서 과산화수소의 농도가 스테인레스 시편 면적에 대하여 $9.51{\times}10^{-2}\;mole/m^2$ 이상일 때 $NO_x$ 발생이 약 80%까지 저감이 되었다. 이러한 결과는 실공정으로 운영되는 스웨덴 AVESTA 산세공정에서 비슷한 정도의 $NO_x$ 생성 저감률을 가져오기 위한 단위산세면적당 과산화수소 주입량의 1/6 정도이다. 실험실에서 행해진 과산화수소 주입에 따른 $NO_x$ 생성저감 결과를 이용하여 단위 산세면적에 대한 경제적인 과산화수소 주입양을 나타내는 영역을 설정하였다.

• Environmental Engineering Research
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• 제20권3호
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• pp.205-211
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• 2015

Reduced forms of iron, such as zero-valent ion (ZVI) and ferrous ion (Fe[II]), can activate dissolved oxygen in water into reactive oxidants capable of oxidative water treatment. The corrosion of ZVI (or the oxidation of (Fe[II]) forms a hydrogen peroxide ($H_2O_2$) intermediate and the subsequent Fenton reaction generates reactive oxidants such as hydroxyl radical ($^{\bullet}OH$) and ferryl ion (Fe[IV]). However, the production of reactive oxidants is limited by multiple factors that restrict the electron transfer from iron to oxygen or that lead the reaction of $H_2O_2$ to undesired pathways. Several efforts have been made to enhance the production of reactive oxidants by iron-induced oxygen activation, such as the use of iron-chelating agents, electron-shuttles, and surface modification on ZVI. This article reviews the chemistry of oxygen activation by ZVI and Fe(II) and its application in oxidative degradation of organic contaminants. Also discussed are the issues which require further investigation to better understand the chemistry and develop practical environmental technologies.

• Asian-Australasian Journal of Animal Sciences
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• 제28권8호
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• pp.1178-1186
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• 2015

Lipid oxidation, colour stability and physico-chemical quality of pork frankfurters with the incorporation of 0.30% sea buckthorn (SBT), 0.10% grape seed (GSE), 0.03% green tea (GTE), 0.12% fenugreek seed (FSE) and 0.10% Acacia catechu (ACE) were studied during 20 days of refrigerated aerobic storage. The SBT and ACE were identified as being the most effective antioxidants to retard lipid oxidation with the potency decreasing in the following order: SBT>ACE>GSE>GTE>FSE based on thiobarbituric acid reacting substances, peroxide value and free fatty acids. In all samples pH and $a_w$ decreased during storage period. The $L^*$ value of treated as well as control samples decreased over time while SBT and ACE exhibited an increased redness producing higher $a^*$ values than other treatments. However, GTE was more effective in increasing $b^*$ values than other treatments at the end of storage. The results suggest that functional plant-derived extracts can be valuable to the modification of frankfurter formulations for improved oxidative stability as well as quality characteristics.

• Journal of the Korean Wood Science and Technology
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• 제34권5호
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• pp.67-78
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• 2006

Modification of polylactic acid (PLA) and 10% maleic anhydride (MAH) with 15% dicumyl peroxide (DCP) based on MAH weight was conducted in the kneader at $160^{\circ}C$ and 30~70 rpm, for 15 min. The resulting MAH-modified PLA (PLA-MA) was then evaluated as a compatibilizer for PLA-wood flour (WF) composites. The FTIR and $^1H$-NMR analysis gave evidence of PLA-MA formation. After kneading and reacting with MAH and DCP, the number (Mn) and the weight average (Mw) molecular weights of PLA decreased as compared to the original PLA. The presence of WF in the composites decreased the tensile strength and several other physical properties. The higher the WF loading resulted in the greater the reduction of tensile strength. An addition of 10% PLA-MA as a compatibilizer to the composites improved the tensile strength and several other physical properties, increased the flow temperature, and decreased the melt viscosity. The improved composite revealed 1.42 times increased in tensile strength but not over PLA alone, and absorbed considerably less water compared to those of the composites free-compatibilizer.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 추계학술대회 논문집 Vol.17
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• pp.727-730
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• 2004

In this paper, so as to investigate the influence of oxidizer for each metal film using the alumina-based slurry, we have peformed the W/Ti metal-CMP process by adding $H_2O_2$ as a representative oxidizer from 1 wt% to 9 wt%, respectively. As an experimental result, for the case of 5 wt% oxidizer added, the removal rates were improved and polishing selectivity of 1.4 : 1 was obtained. Also, we compared the effects of oxidizer or W-CMP process with three different kind of oxidizers with 5 wt% hydrogen peroxide such as $Fe(NO_3)_3$, $H_2O_2$, and $KIO_3$. Finally, atomic force microscope (AFM) measurements were carried out for the analysis of surface morphology and root mean square (RMS) roughness after CMP Process.

• Toxicological Research
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• 제20권1호
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• pp.13-20
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• 2004

The purpose of this study is to compare the biocompatibility of commercial purity Ti, Ti-6AI-4V and Ti-6AI-7Nb alloy specimens with and without surface treatment in mouse abdominal connective tissue in vivo. Each metal was implanted into specific abdominal subdermal tissue site of female mouse. After 4 weeks, the implants were removed and abdominal tissues were fixed, dehydrated and embedded in glycol methacrylate resin. And the tissues were histologically prepared for microscopical evaluation. It was characterized by the presence of connective tissue with fibrous capsule surrounding the implant. The fibrous tissue surrounding the implant was studied to determine the biocompatibility of implanted metals. The average thickness of the fibrous capsule formed around the implant was much thinner for the hydrogen peroxide added hydrochloric acid solution-treated specimen than for the others. The results of this evaluation indicate that modification of the surface properties of titanium and titanium alloy implants changes the biological properties in the abdominal connective tissue. In conclusion, these observations suggest that the proper surface treatment performed in the study is effective for the improvement of biocompatibility.

• 생약학회지
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• 제36권1호통권140호
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• pp.34-37
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• 2005

Reactive oxygen species (ROS) are known to cause oxidative modification of DNA, proteins, lipids and small cellular molecules and are associated with tissue damage and are the contributing factors for inflammation, aging, cancer, arteriosclerosis, hypertension and diabetes. We screened the anti-oxidants in V79-4 hamster lung fibroblast cells induced by hydrogen peroxide with eighteen pure compounds isolated from natural products. Allantoin, brassicasterol, and hypaconitine were found to strongly scavenge intracellular reactive oxygen species, which is measured by dichlorodihydrofluorescin diacetate method (DCHF-DA), and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical.

• 한국전기전자재료학회논문지
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• 제16권12S호
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• pp.1181-1186
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• 2003

Chemical Mechanical Polishing (CMP) is an essential dielectric planarization in multilayer microelectronic device fabrication. In the CMP process, it is necessary to minimize the extent of surface defect formation while maintaining good planarity and optimal material removal rates. The polishing mechanism of W-CMP process has been reported as the repeated process of passive layer formation by oxidizer and abrasion action by slurry abrasives. Thus, it is important to understand the effect of oxidizer on W passivation layer, in order to obtain higher removal rate (RR) and very low non-uniformity (NU %) during W-CMP process. In this paper, we compared the effects of oxidizer or W-CMP process with three different kind of oxidizers with 5 wt% hydrogen peroxide such as Fe(NO$_3$)$_3$, H$_2$O$_2$, and KIO$_3$. The difference in removal rate and roughness of W in stable and unstable slurries are believed to caused by modification in the mechanical behavior of Al$_2$O$_3$ particles in presence of surfactant stabilizing the slurry.

• Bulletin of the Korean Chemical Society
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• 제30권2호
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• pp.355-362
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• 2009

The chemical modification of multi-wall carbon nanotubes (MWNTs) is an emerging area in material science. In the present study, hydroxyl functionalized oxovanadium(IV) Schiff-base; N,N'-bis(4-hydroxysalicylidene)-ethylene-1, 2-diamineoxovanadium(IV), [VO($(OH)_2$-salen)]; has been covalently anchored on modified MWNTs. The new modified MWNTs ([VO($(OH)_2$-salen)]-MWNTs]) have been characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron (XPS), UV-Vis, Diffuse reflectance (DRS), FT-IR spectroscopy and elemental analysis. The analytical data indicated a composition corresponding to the mononuclear complex of tetradentate Schiff-base ligand. The characterization of the data showed the absence of extraneous complex, retention of MWNTs and covalently anchored on modified MWNTs. Liquid-phase oxidation of cyclohexane with $H_2O_2$ to a mixture of cyclohexanone, cyclohexanol and cyclohexane-1,2-diol in $CH_3$CN have been reported using oxovanadium(IV) Schiff-base complex covalently anchored on modified MWNTs as catalysts. This catalyst is more selective toward cyclohexanol formation.

• KSBB Journal
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• 제21권1호
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• pp.16-19
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• 2006

최근의 연구에 의하면 열이나, 산화적 스트레스에 대해서 NDPK는 구조적인 변화를 유발하며, 효소 활성과 구조가 oxidant에 의해 변화된다는 보고를 근거로 하여 정상적인 효모균주와 효모의 NDPK 유전자가 파괴된 mutant에서, 산화적 스트레스에 관련된 역할을 규명하고자 2-D 전기영동 방법을 통해서, $H_2O_2$의 처리전과 처리 후에 전사패턴이 변화된 유전자들, 즉, 산화적조절 신호체제에 연관되어졌을 것이라고 생각되어지는 몇 개의 단백질 리스트를 얻었다. 이 결과는 NDPK의 redox state의 조절에 관련된 효소의 성질을 규명함에 있어 유용한 유전자 신호 체제정보를 제공할 것으로 생각되어진다.