• 한국포장학회지
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• 제26권1호
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• pp.19-23
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• 2020

Al-laminated packaging film incorporating ascorbic acid or tocopherol at inner food contact layer was tested in the potential to improve antioxidative preservation of powdered infant formula under CO₂-enriched atmosphere. Product of 200 g was packaged with the packaging film containing 0.3% antioxidant in sealant layer of low density polyethylene and stored at 30℃ for 286 days with periodic measurement of package atmosphere and product's quality attributes. The CO₂-flushed package resulted in shrinkage of tight contact between the product and the film not allowing gas sampling of package atmosphere after 140 days. Package of tocopherol-incorporated film allowed some ingress of oxygen after 112 days presumably due to its weakening of heat-seal area. The increased oxygen concentration in the tocopherol-added film package led to the concomitant increase of peroxide value, an index of lipid oxidation. On the other hand, packaging of ascorbic acid-added film pouch could suppress lipid oxidation marginally in consistent manner compared to control package without any antioxidant.

• 상하수도학회지
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• 제31권4호
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• pp.273-279
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• 2017

Optimal processes to remove chromaticity at E water treatment plant(WTP) mainly caused by algae of E lake in Jeju island were investigated based on lab-tests of chlorine and ozone oxidation. 42.9% of chromaticity of filtered water was removed by chlorine oxidation under pH 7.0~8.0, dose of 1.0 mg/L with contact time of 30~60 min. On the other hand, chromaticity removal was 71.4% when post-ozone dose of 0.9~1.9 mg/L and pH 9.0, while it was increased to 86.7% under post-ozone dose of 3.1~7.3 mg/L and pH 9.0. However, there was no significant chromaticity removal efficiency increase when ozone doses were higher than 5.0 mg/L regardless of feeding point(i.e., pre-ozonation and post-ozonation) and pHs(i.e., 7.0 and 9.0.) under the experimental conditions. Based on the results, chlorine oxidation using existing chlorination facilities at the WTP is recommended for lower chromaticity while ozone oxidation is recommended for higher chromaticity by installing new ozone feeding facilities.

• 한국전기전자재료학회논문지
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• 제20권6호
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• pp.561-565
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• 2007

Because of a good wear resistance and a stable contact resistance, Ag-CdO is widely used as electrical contact material. But, the Cd-oxide mainly exists as a coarse particle and adversely affected to environment. As a reason, $Ag-SnO_2$ alloy has been developed. The Sn-oxide maintains stable and fine particle even at high temperature. In order to investigate the effect of Misch metal (Mm) additional that affects the formation of the oxide and the formation of fine matrix Ag, we studied the microstructures and properties of Ag-Sn-In(-Mm) material fabricated by rapid solidification process. The experimental procedure were melting using high frequency induction, melt spinning, and internal oxidation. The Mm addition makes Ag matrix more fine than no Mm addition. The reason is that the addition of Misch metal decreased a latent heat of fusion of alloy, as a result the rapid solidification effect of alloy is increased. The maximum hardness shows at 0.3 wt%Mm. after that the hardness is decreased until 0.4 wt% Mm, but still larger than no Mm addition alloy. At 0.5 wt% Mm alloy, the precipitation of Misch metal causes a decrease of hardness than no Mm addition alloy.

• Journal of Electrochemical Science and Technology
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• 제5권3호
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• pp.82-86
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• 2014

This work presents the variation of formic acid oxidation on Pt depending on hydrodynamic condition using a rotating disk electrode. As the rotating speed increases, the oxidation rate of formic acid decreases under voltammetric and chronoamperometric measurements. The coverages of poison formed from formic acid during the chronoamperomertric investigations decrease when the rotating speed increases. As the roughness factor of Pt electrode surface increases, on the other hand, the current density of formic acid oxidation increases. These observations are discussed in terms of the tangential flow along Pt electrode surfaces generated by the rotating disk electrode, which reduces a contact time between formic acid and a Pt site, thus the formic acid adsorption.

• 한국자기학회지
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• 제13권2호
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• pp.47-52
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• 2003

DC 마그네트론 스파터법과 RLSA(Radial Line Slot Antenna)을 이용한 마이크로파 여기 프라즈마를 이용하여 Ta/Cu/Ta/NiFe/Cu/Mn$_{75}$Ir$_{25}$/ $Co_{70}$Fe$_{30}$/Al-oxide 구조의 접합을 제조한 후, contact-mode AM(Atomic Force Microscope)을 이용하여 Al 산화막의 국소전도 특성의 평가를 수행하였다. AFM 동시전류측정으로부터, 얻어지는 표면상과 전류상은 대응하지 않는다. 국소 전류-전압(I-V)의 측정 결과, 전류상은 절연층의 barrier height의 분포를 나타내고 있다는 것을 알았다.다.다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제17권2호
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• pp.7-14
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• 2012

Batch tests were carried out to evaluate the thermal treatment of low volatile organic compounds in low-permeability soil. The chemical oxidation by sodium persulfate catalyzed by heat and Fe (II) was evaluated. Enhanced persulfate oxidation of n-decane (C-10), n-dodecane (C-12), n-tetradecane (C-14), n-hexadecane (C-16), and phenanthrene was observed with thermal catalyst, indicating increased sulfate radical production. Slight enhancement of the pollutants oxidation was observed when initial sodium persulfate concentration increased from 5 to 50 g/L. However, the removal efficiency greatly decreased as soil/water ratio increased. It indicates that mass transfer of the pollutants as well as the contact between the pollutants and sulfate radical were inhibited in the presence of solids. In addition, more pollutants can be adsorbed on soil particles and soil oxidant demand increased when soil/water ratio becomes higher. The oxidation of the pollutants was significantly improved when catalyzed by Fe(II). The sodium persulfate consumption increased at the same time because the residual Fe(II) acts as the sulfate radical scavenger.

• International Journal of Automotive Technology
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• 제7권1호
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• pp.75-82
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• 2006

Fretting corrosion widely known as a degradation mechanism refers to the combination of fretting wear and corrosion such as oxidation. This paper critically reviews the works published previously on fretting corrosion of electrical connectors. Various experimental approaches such as testing machines, material selection, testing environments, acceleration testing techniques and preventing methods are addressed. Future research prospects are suggested.

• Corrosion Science and Technology
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• 제17권2호
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• pp.45-53
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• 2018

A new 80Ti-15Ta-5Zr wt% alloy surface was protected by anodic oxidation in phosphoric acid solution. The protective oxide layer (TiO2, ZrO2 and Ta suboxides and thickness of 15.5 nm) incorporated $PO{_4}^{3-}$ ions from the solution, according to high resolution XPS spectra. The AFM analysis determined a high roughness with SEM detected pores (20 - 50 nm). The electrochemical studies of bare and anodically oxidized Ti-15Ta-5Zr alloy in Carter-Brugirard saliva of different pH values and saliva with 0.05M NaF, pointed to a nobler surface for the protected alloy, with a thicker electrodeposited oxide layer acting as a barrier against aggressive ions. The oxidized alloy significantly decreased corrosion current densities and total quantity of ions released into the oral environment in comparison with the bare one, at higher polarisation resistance and protective capacity of the electrodeposited layer. The impedance data revealed a bi-layered oxidation film formed by: a dense, compact, barrier layer in contact with the metallic substrate, decreasing the potential gradient across the metal/oxide layer/solution interface, reducing the anodic dissolution and a more permissive, porous layer in contact with the electrolyte. The open circuit potential for protected alloy shifted to nobler values, with thickening of the oxidation film signifying long-term protection.

• 환경위생공학
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• 제14권3호
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• pp.10-21
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• 1999

The purpose of study were to research the characteristics of water variation adding humic acids to distilled water after ozonation. Upon investigating pH variation with contact time after providing distilled water+air, distilled water+ozone and distilled water-humic acid-air in reactor, it reduced after 60 minute in inletting air and in spite of short contact time did suddenly in inletting ozone. TOC and UV-254 continued to increase with contact time of ozone and humic acids. $NH^{4+}-N$ did slowly increase or decrease after constant contact time of ozone, because $NH^{4+}-N$ was converted into $No^3-N$ by ozone. T-N did suddenly increase after 90minute, but T-P did rarely fluctuate for total experiment. Total 30 species of organic matter were detected by GS/MSD, but 14 species did really tend to increase except for matter identified in distilled water and blank test. Humic acids generated $aliphatic{\cdot}aromatic$ hydrocarbon, alcohol and amine etc., and did various matters without inflow course of contaminants.

• 한국재료학회지
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• 제29권6호
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• pp.378-384
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• 2019

Ice accumulation on Aluminum Conductor Steel Reinforced(ACSR) cable during winter is an important matter in terms of safety, economy, and efficient power supply. In this work, the ice adhesion strengths of ACSR cable oxidized during different periods(7 years oxidized and 15 years oxidized) are evaluated. At first, a plate type dry oxidation standard specimen, whose surface characteristics are similar to those of ACSR cable, is prepared. Dry oxidation standard specimens are heat-treated at $500^{\circ}C$ for 20, 60, and 120 minutes in order to obtain different degrees of oxidation. After the dry oxidation, surface properties are analyzed using contact angle analyzer, atomic force microscopy, spectrophotometer, and gloss meter. The ice adhesion strengths are measured using an ice pull-off tester. Correlations between the surface properties and the ice adhesion strength are obtained through a regression analysis indicating a Boltzmann equation. It is revealed that the ice adhesion strength of 15-year oxidized ACSR cable is approximately 8 times higher than that of ACSR-bare.