Isotactic polyacrylonitrile (PAN) with triad isotacticity of 0.53, which was determined by 13C NMR, using dialkylmagnesium as an initiator, was successfully synthesized. Isothermal treatment of iso-PAN was conducted in air at 200, 220, 250 and 280℃. Structural evolutions and chemical changes were studied with Fourier transformation infrared and wide-angle X-ray diffraction during stabilization. A new parameter CNF=I2240cm-1/ (I1595cm-1+f*I1595cm-1) was defined to evaluate residual nitrile groups. Crystallinity and crystal size were calculated with X-ray diffraction dates. The results indicated that the nitrile groups had partly converted into a ladder structure as stabilization proceeded. The rate of reaction increased with treatment temperature; crystallinity and crystal size decreased proportionally to pyrolysis temperature. The iso-conversional method coupled with the Kissinger and Flynn-Wall-Ozawa methods were used to determine kinetic parameters via differential scanning calorimetry analysis with different heating rates. The active energy of the reaction was 171.1 and 169.1 kJ/mol, calculated with the two methods respectively and implied the sensitivity of the reaction with temperature.

MAO(Micro-Arc Oxidation) method was used to make surface on 6063 Al specimen. This study was focused on an influence of voltage, density of electrolyte and a period of treatment on the change of surface microstructure by using SEM(Scanning Electron Microscope), EDS(Energy Dispersive X-ray Spectroscopy). The microstructure shows higher roughness and thicker oxidized layer with increase of voltage and maintaining period of treatment. The density of electrolyte affected a formation of more dense surface and increase of a oxidized layer.

In this study, the used DOCs, which could remove the air pollutants such as CO and HC in the exhaust gas from diesel vehicle, were remanufactured by various conditions. Their catalytic performances and characterization were also investigated. The remanufacturing process of the deactivated DOCs includes high temperature cleaning of incineration, ultrasonic cleaning for washing with acid/base solutions to remove deactivating materials deposited to the surface of the catalysts, and active component reimpregnation for reactivating catalytic activity of them. The catalytic performance tests of the remanufactured DOCs were carried out by the diesel engine dynamo systems and chassi dynamo systems in CVS-75 mode. All prepared catalysts were characterized by the optical microscopes, SEM, EDX, porosimeter and BET to investigate correlations between catalytic reactivity and surface characteristics of them. The remanufactured DOCs at various conditions showed the improved catalytic performances reaching to 90% of fresh DOC, which is attributed to remove the deactivating materials from the surface of the used DOC through the analysis of catalytic performance test and their characterization.

유리지방산(FFA), 글리세롤, MAG, 세사몰, 수용성 참깨 박 추출물(ASM) 첨가에 의한 213oC에서 21분 볶아 제조된 참기름의 180oC 열산화 시 세사몰과 세사몰린 함량 변화를 분석하였다. 90분간의 열산화에 의해 FFA와 MAG가 10% 첨가된 시료는 각각 0.94, 0.70 mM의 세사몰이 유의적으로 추가 생성되었으나 대조구는 0.09 mM만 증가하였다(p < 0.05). 세사몰린의 경우 FFA와 MAG 10% 첨가 시료는 대조구에 비해 15 및 18% 유의적으로 감소하였다(p < 0.05). 1.5와 2.5 mM 첨가 세사몰은 세사몰린의 유의적인 변화를 유발하지 않았다(p > 0.05). ASM 첨가 시료에서 세사몰과 세사몰린의 일관적인 변화는 확인되지 않았다. 고온에서 볶은 참깨로부터 착유된 참기름의 가열 산화 시 세사몰 생성 및 세사몰린 분해에는 FFA 및 MAG 같은 유지산화생성물의 함량에 주로 영향을 받는 것으로 사료된다.

Peroxiredoxin II (Prdx II; a typical 2‐Cys Prdx) has been originally isolated from erythrocytes, and its structure and peroxidase activity have been adequately studied. Mice absent to Prdx II proteins had heinz bodies in their peripheral blood, and morphologically abnormal cells were detected in the dense red blood cell (RBC) fractions, which contained markedly higher levels of reactive oxygen species (ROS). In this study, a labeling experiment with the thiol‐modifying reagent biotinylated iodoacetamide (BIAM) in Prdx I‒/‒ mice revealed that a variety of RBC proteins were highly oxidized. To identify oxidation‐sensitive proteins in Prdx II‒/‒ mice, we performed RBC comparative proteome analysis in membrane and cytosolic fractions by nano‐UPLC‐MSE shotgun proteomics. We found oxidation‐sensitive 54 proteins from 61 peptides containing cysteine oxidation, and analyzed comparative expression pattern in healthy RBCs of Prdx II+/+ mice, healthy RBCs of Prdx II‒/‒ mice, and abnormal RBCs of Prdx II‒/‒ mice. These proteins belonged to cellular functions related with RBC lifespan maintain, such as cytoskeleton, stress‐induced proteins, metabolic enzymes, signal transduction, and transporters. Furthermore, protein networks among identified oxidation sensitive proteins were analyzed to associate with various diseases. Consequently, we expected that RBC proteome may provide clues to understand redox‐imbalanced diseases.

Growing evidence indicates that oxidized low density lipoprotein (LDL) may promote atherogenesis. Therefore, inhibition of LDL oxidation may impede this process. The inhibitory effected on the susceptibility of human LDL to Cu²+ or macrophages induced oxidation was investigated by monitoring thiobarbituric acid reactive substances (TBARS). Organosulfur compounds of garlic oil contains diallyldisulfide, diallyltrisulfide, diallyltetrasulfide, and diallyl pentasulfide in order. Garlic oil inhibited LDL oxidation by Cu²+, or macrophages in a dose dependently, with a 20~60 μg, as increased TBARS assay. Garlic oil, at 60 μM, almost completely inhibited macrophages induced increase in electrophoretic mobility of LDL. When compared with several other antioxidants, probucol showed highest ability,and then garlic oil showed a much higher ability than natural occurring antioxidants, α-tocopherol and ascorbic acid. The results suggested that garlic oil might play the inhibitory effects in the process of LDL oxidation.

This paper presented experimental results for circulation type UV-TiO₂ photocatalytic oxidation process. We have developed UV-TiO₂ photocatalytic oxidation process with activated carbon to control odor and VOCs in indoor and industrial applications. In this study, common indoor air pollutants, namely ammonia, formaldehyde, hydrogen disulfide, toluene were selected to investigate their efficiencies for UV-TiO₂ photocatalytic oxidation. In high concentration test, the decomposition efficiency was high in order as ammonia, toluene, formaldehyde, hydrogen disulfide. Three type of individual processes are tested for ability to increase decomposition efficiency. UV-TiO₂ photocatalytic oxidation combined process with activated carbon was excellent among the three type processes without reference to gas species. It was considered that this circulation type process will overcome short retention time for treatment for UV-TiO₂ photocatalytic oxidation. It will promise that this circulation type UV-TiO₂ photocatalytic oxidation combined process can apply indoor and industrial applications to remove odor and VOCs quickly.

Pt nanoparticle catalysts incorporated on RuO2 nanowire support were successfully synthesized and their electrochemical properties, such as methanol electro-oxidation and electrochemically active surface (EAS) area, were demonstrated for direct methanol fuel cells (DMFCs). After fabricating RuO2 nanowire support via an electrospinning method, two different types of incorporated Pt nanoparticle electrocatalysts were prepared using a precipitation method via the reaction with NaBH4 as a reducing agent. One electrocatalyst was 20 wt% Pt/RuO2, and the other was 40 wt% Pt/RuO2. The structural and electrochemical properties of the Pt nanoparticle electrocatalysts incorporated on electrospun RuO2 nanowire support were investigated using a bright field transmission electron microscopy (bright field TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and cyclic voltammetry. The bright field TEM, XRD, and XPS results indicate that Pt nanoparticle electrocatalysts with sizes of approximately 2-4 nm were well incorporated on the electrospun RuO2 nanowire support with a diameter of approximately 50 nm. The cyclic voltammetry results showed that the Pt nanoparticle catalysts incorporated on the electrospun RuO2 nanowire support give superior catalytic activity in the methanol electro-oxidation and a higher electrochemically active surface (EAS) area when compared with the electrospun Pt nanowire electrocatalysts without the RuO2 nanowire support. Therefore, the Pt nanoparticle catalysts incorporated on the electrospun RuO2 nanowire support could be a promising electrode for direct methanol fuel cells (DMFCs).

In this paper, high temperature oxidation behavior of newly developed alloys, Ti-6Al-4Fe and Ti-6Al-1Fe, is examined. To understand the effect of Fe on the air oxidation behavior of the Ti-Al-Fe alloy system, thermal oxidation tests are carried out at 700˚C and 800˚C for 96 hours. Ti-6Al-4V alloy is also prepared and tested under the same conditions for comparison with the developed alloys. The oxidation resistance of the Ti-Al-Fe alloy system is superior to that of Ti-6Al-4V alloy. Ti-6Al-4V shows the worst oxidation resistance for all test conditions. This is not a result of the addition of Fe, but rather it is due to the elimination of V, which has deleterious effects on high temperature oxidation. The oxidation of the Ti-Al-Fe alloy system follows the parabolic rate law. At 700˚C, Fe addition does not have a noticeable influence on the amount of weight gain of all specimens. However, at 800˚C, Ti-6Al-4Fe alloy shows remarkable degradation compared to Ti-6Al-1Fe and Ti-6Al. It is discovered that the formation of Al2O3, a diffusion resistance layer, is remarkably hindered by a relative decrease of the α volume fraction. This is because Fe addition increases the volume fraction of β phase within the Ti-6Al-xFe alloy system. Activities of Al, Ti, and Fe with respect to the formation of oxide layers are calculated and analyzed to explore the oxidation mechanism.

Polyacrylonitrile (PAN) fibers were pre-oxidized in a temperature range of 180-275℃. The effects of positive and negative stretching on the structure and morphology of PAN fiber in the pre-oxidation process were studied by FTIR spectroscopy, XRD, and SEM. Mechanical property changes were also investigated. No changes in the movement and intensity of functional groups of PAN fibers were caused by positive stretching of up to 10% and negative stretching down to -8%. The crystal structure can be affected by the positive stretching and negative stretching. The maximum strength is 479.81 MPa when the stretching is positive, and the maximum strength is 420.55 MPa when the stretching is negative.

본 연구에서는 정수처리용 세라믹 한외여과 빛 광촉매의 혼성공정에서 휴믹산 농도 및 광산화, 흡착의 영향을 알아보았다. 휴믹산 농도 각각 2mg/L와 4 mg/L 일 때 UF 단독 공정 및 광촉매를 투입한 공정, UV를 조사한 공정을 막오염에 의한 저항(Rf) 및 투과선속(J), 총여과부피 (VΤ) 측면에서 고찰하였다. 휴믹산 농도가 낮아질수록 Rf는 급격히 감소하고 J는 증가하여, 휴믹산 농도 2 mg/L에서 VΤ는 가장 높았다. 탁도의 평균 처리효율은 휴믹산 농도가 증가할수록 감소하였으나, 4 mg/L에서 휴믹산의 처리효율이 가장 높았다. 이러한 결과는 낮은 휴믹산 농도에서 휴믹산 대부분이 분리막에 의해 제거되고 막을 통과한 일부 휴믹산은 광촉매에 흡착 산화되어, 처리수의 수질이 휴믹산 2 mg/L 와 4 mg/L 에서 거의 같고 원수의 수질은 4 mg/L에서 더 높기 때문이다. 광산화와 흡착의 영향 실험에서 UF + TiO2 + UV 공정의 J가 가장 높게 유지되어, 180분 운전 후 VΤ가 가장 높았다. 휴믹산 및 탁도의 처리효율을 비교한 결과, 휴믹산 농도가 2 mg/L 에서 4mg/L로 증가하였을 때 광산화 보다 광촉매 흡착이 더 주요한 역할을 하였다.

The current study was carried out to investigate the effect of addition of Rhus veniciflua Stokes oil (RVSO) and black garlic extract (BGE) on the lipid oxidation in Hanwoo (Korean cattle) beef model systems. The RVSO at 0.2% inhibited the TBARS (2-thiobarbituric acid reactive substances) formation when tested in liposome model system. The antioxidant effect of RVSO was further found to be similar to 0.2% butylated hydroxy toluene (BHT) and 0.01% vitamin E. On the other hand, BGE at 0.1% also showed the inhibition of TBARS formation in 4% NaCl-added Hanwoo beef patty and found to have slightly lower (p<0.05) effect than 0.1% vitamin E but higher (p<0.05) effect than 0.1% BHT. Results of this study indicated that both RVSO and BGE possess strong antioxidant effects and help to increase the oxidative stability in Hanwoo beef products.

This study investigated the high temperature oxidation behavior of Ni-22.4%Fe-22%Cr-6%Al (wt.%) porous metal. Two types of open porous metals with different pore sizes of 30 PPI and 40 PPI (pore per inch) were used. A 24-hour TGA test was conducted at three different temperatures of , and . The results of the BET analysis revealed that the specific surface area increased as the pore size decreased from 30 PPI to 40 PPI. The oxidation resistance of porous metal decreased with decreasing pore size. As the temperature increased, the oxidation weight gain of the porous metal also increased. Porous metals mainly created oxides such as , , , and . In the 40 PPI porous metal with small pore size and larger specific surface area, the depletion of stabilizing elements such as Al and Cr occurred more quickly during oxidation compared to the 30 PPI porous metal. Ni-Fe-Cr-Al porous metal's high-temperature oxidation micro-mechanism was also discussed.

The stress-strain responses and oxidation properties of cold-rolled Zr-1.5Nb-O and Zr-1.5Nb-O-S alloys were studied. The U.T.S. (ultimate tensile strength) of cold-rolled Zr-1.5Nb-O-S alloy with 160 ppm sulfur (765 MPa) were greater than that of Zr-1Nb-1Sn-0.1Fe alloy (750 MPa), achieving an excellent mechanical strength even after the elimination of Sn, an effective solution strengthening element. The addition of sulfur increased the strength at the expense of ductility. However, the ductile fracture behavior was observed both in Zr-Nb-O and Zr-Nb-O-S alloys. The beneficial effect of sulphur on the strengthening was observed in the cold rolled Zr-1.5Nb-O-S alloys. The activation volume of cold-rolled Zr-1.5Nb decreased with sulfur content in the temperature region of dynamic strain aging associated with oxygen atoms. Insensitivity of the activation volume to the dislocation density and the decrease of the activation volume at a higher temperature where the dynamic strain aging occurs support the suggestion linking the activation volume with the activated bulge of dislocations limited by segregation of oxygen and sulfur atoms. The addition of sulfur was also found to improve the oxidation resistance of Zr-Nb-O alloys.

We study the relationships between the thermal emissivity of nuclear graphites (IG-110, PCEA, IG-430 and NBG-18) and their surface structural change by oxidation using scanning electron microscope and X-ray diffraction (XRD). The nonoxidized (0% weight loss) specimen had the surface covered with glassy materials and the 5% and 10% oxidized specimens, however, showed high roughness of the surface without glassy materials. During oxidation the binder materials were oxidized first and then graphitic filler particles were subsequently oxidized. The 002 interlayer spacings of the non-oxidized and the oxidized specimens were about 3.38~3.39a. There was a slight change in crystallite size after oxidation compared to the nonoxidized specimens. It was difficult to find a relationship between the thermal emissivity and the structural parameters obtained from the XRD analysis.

Recently, nanotubes have considerably researched because of their novel application about photocatalysis, dye-sensitized solar cells (DSSCs), lithium ion battery, etc. In this work, self-standing nanotube arrays were fabricated by anodic oxidation method using pure Ti foil as a working electrode in ethylene glycole with 0.3M + . Growth behavior of nanotube arrays was compared according to temperature, voltage and time. The morphology, structure and crystalline of anodized nanotube arrays were observed by FE-SEM (field emission scanning electron microscope) and XRD (X-ray diffraction).

Self-standing TiO2 nanotube arrays were fabricated by potentiostatic anodic oxidation method using pure Ti foil as a working electrode and ethylene glycol solution as electrolytes with small addition of NH4F and H2O. The influences of anodization temperature and time on the morphology and formation of TiO2 nanotube arrays were investigated. The fabricated TiO2 nanotube arrays were applied as a photoelectrode to dye-sensitized solar cells. Regardless of anodizing temperature and time, the average diameter and wall thickness of TiO2 nanotube show a similar value, whereas the thickness show a different trend with reaction temperature. The thickness of TiO2 nanotube arrays anodized at 20℃ and 30℃ was time-dependent, but on the other hand its at 10℃ are independent of anodization time. The conversion efficiency is low, which is due to a morphology breaking of the TiO2 nanotube arrays in manufacturing process of photoelectrode.

Zirconium diboride (ZrB2) and mixed diboride of (Zr0.7Ta0.3)B2 containing 30 vol.% silicon carbide (SiC) composites were prepared by hot-pressing at 1800˚C. XRD analysis identified the high crystalline metal diboride-SiC composites at 1800˚C. The TaB2 addition to ZrB2-SiC showed a slight peak shift to a higher angle of 2-theta of ZrB2, which confirmed the presence of a homogeneous solid solution. Elastic modulus, hardness and fracture toughness were slightly increased by addition of TaB2. A volatility diagram was calculated to understand the oxidation behavior. Oxidation behavior was investigated at 1500˚C under ambient and low oxygen partial pressure (pO2~10-8 Pa). In an ambient environment, the TaB2 addition to the ZrB2-SiC improved the oxidation resistance over entire range of evaluated temperatures by formation of a less porous oxide layer beneath the surface SiO2. Exposure of metal boride-SiC at low pO2 resulted in active oxidation of SiC due to the high vapor pressure of SiO (g), and, as a result, it produced a porous surface layer. The depth variations of the oxidized layer were measured by SEM. In the ZrB2-SiC composite, the thickness of the reaction layer linearly increased as a function of time and showed active oxidation kinetics. The TaB2 addition to the ZrB2-SiC composite showed improved oxidation resistance with slight deviation from the linearity in depth variation.

The effects of La addition to Ni/CeO2 methane partial oxidation catalysts were investigated. Catalysts were prepared by the impregnation and urea methods. In the preparation of catalysts, La content was changed from 1 wt% to 3wt%. Catalysts that contain 2wt% La showed the highest methane conversion of about 80% and CO selectivity of 84% and H2 selectivity of 70%. This result may be stemmed from that, when La content is 2wt%, a fluorite oxide-type structure is well formed and carbon deposition is also decreased. Among the catalysts, 2.5wt% Ni/Ce(La)Ox showed the highest catalytic activity. From the experiment of changing reaction temperature with 2.5wt% Ni/Ce(La)Ox catalyst, it was found that the optimum reaction temperature is 750℃ and at this temperature methane conversion was about 90%, CO and H2 selectivities were 94 and 80%, respectively.