• 한국세라믹학회지
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• 제37권1호
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• pp.96-101
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• 2000

Comparative studies on microstructure, and mechanical and anti-oxidation properties between TiN and Ti-Si-N films were performed. The Ti-Si-N films were deposited on high-speed steel and silicon wafer substrates by plasma-assisted chemcial vapor deposition(PACVD) technique. The Si addition to TiN film caused to change the microstructure such as grain size refinement, randomly multi-oriented microstructure, and nano-sized codeposition of silicon nitride in the TiN matrix. The Ti-Si-N film, contains Si content of ∼7 at.%, showed the micro-hardness value of ∼3400 HK, which was higher than the pure TiN film whose hardness was ∼1500HK. The Ti-Si(7 at.%)-N film also showed much improved anti-oxidation properties compared with those of the pure TiN film. These properties were also related to the microstructure of Ti-Si(7 at.%)-N film was formed and retarded further oxidation of the nitridelayer. These properties were also related to the microstructure of Ti-Si(7 at.%)-N film which was characterized by nano-sized precipitates of silicon nitride phase in the TiN matrix and randomly oriented grains.

• Carbon letters
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• 제12권2호
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• pp.116-119
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• 2011

C/SiC composites were prepared by boron nitride (BN)-assisted liquid silicon infiltration (LSI), and their anti-oxidation and mechanical properties were investigated. The microstructures, bulk densities, and porosities of the C/SiC composites demonstrated that the infiltration of liquid silicon into the composites improved them, because the layered-structure BN worked as a lubricant. Increasing the amount of BN improved the anti-oxidation of the prepared C/SiC composites. This synergistic effect was induced by the assistance of BN in the LSI. More thermally stable SiC was formed in the composite, and fewer pores were formed in the composite, which reduced inward oxygen diffusion. The mechanical strength of the composite increased up to the addition of 3% BN and decreased thereafter due to increased brittleness from the presence of more SiC in the composite. Based on the anti-oxidation and mechanical properties of the prepared composites, we concluded that improved anti-oxidation of C/SiC composites can be achieved through BN-assisted LSI, although there may be some degradation of the mechanical properties. The desired anti-oxidation and mechanical properties of the composite can be achieved by optimizing the BN-assisted LSI conditions.

• 한국식생활문화학회지
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• 제18권2호
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• pp.111-122
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• 2003

This studies were performed to develop a Korean traditional folk liquor namely Gangha-ju has been prepared at Bosung district in Korea, and manufacturing conditions and anti-oxidation activity and anti-microbial activity of Gangha-ju were investigated. Ethyl-alcohol 20% and 30% Gangha-ju were brewed with glutinous rice wine, distilled liquor and 6 herbs of ginger, cinnamon, etc. Chemical and physical properties of 30% Gangha-ju were acidity 0.22, pH 4.31, amino acidity 3.26, transmittance 59 and conductivity $911\;{\mu}s/m$, and 20% Gangha-ju were 0.43, 4.20, 6.26, 62 and $924\;{\mu}s/m$. Volatile flavor compounds of ethyl alcohol, acetic acid, butanol, n-amyl alcohol, iso-pentyl alcohol, ethyl acetate, butyl acetate, acetaldehyde and furfural were detected, and main aroma compounds of Gangha-ju were isopentyl alcohol and ethyl acetate. Anti-oxidation activity by DPPH method was evaluated 31.32%, and nitrite scavenging effect was 31.79%. Anti-microbial activity against several microorganisms was pronounced strong activity over a wide range of test organisms, and Leuconostoc mesenteroids and Salmonella Ttyphimurium, Staphylococcus epidermidis were found to be more sensitive to Gangha-ju than Escherichia coli and Aspergillus flavus.

• 폴리머
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• 제24권2호
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• pp.237-244
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• 2000

탄화 매트릭스의 전구체로 사용된 페놀수지에 세라믹 분말인 이규화몰리브덴 (MoSi$_2$)을 0, 4, 12, 20%의 중량비로 각각 고르게 분산시켜, 여기에 PAN계 탄소섬유를 함침하여 프리프레그법을 이용하여 일방향 탄소섬유/페놀수지 복합재료를 제조하였으며, 이를 다시 탄화(110$0^{\circ}C$) 시켜서 일방향 탄소/탄소 복합재료를 제작하였다. 본 연구에서는 난소/탄소 복합재료에 산화 억제제로 사용된 MoSi$_2$의 첨가량에 따른 복합재료의 산화거동을 산화분위기 하 600-100$0^{\circ}C$의 온도범위에서 조사하였다. 그 결과, MoSi$_2$를 함유한 탄소/탄소 복합재료는 복합재료 내치 기공 감소와 산소에 대한 유동 확산 방지막의 형성으로 인하여 카본 활성종이 방해를 받아 MoSi$_2$를 함유하지 않은 것에 비해 산화속도가 감소되어 내산화성이 향상되었다. 이는 산소의 공격에 대한 보호층을 형성하는 MoSi$_2$ 고유의 특성에 따른 영향이라 사료된다.

• 대한화학회지
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• 제18권6호
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• pp.443-446
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• 1974

內然機關에서 採取한 廢油를 黃酸白土 處理하여 얻어진 再生油는 원래 들어 있던 添加劑, 特히 酸化防止劑와는 相關없이 酸化安定性이 좋아졌다. 이러한 性質의 改善은 芳香族化合物이 거의 25%나 增加하는 事實로 미루어 耐酸化性物質의 生性에 基因하는 것으로 考察된다.

• 사상체질의학회지
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• 제24권4호
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• pp.51-61
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• 2012

Objectives : The purpose of this study was to investigate the anti-atherosclerotic effects of 4 herbal formulas for Sasang constitutional medicine (Yeoldahanso-tang: YDHST, Yanggyeoksanhwa-tang: YGSHT, Cheongsimyeonja-tang: CSYJT and Taeeumjowi-tang: TEJWT). Methods : The antioxidant activities of herbal formulas were studied by measuring free radical scavenging activities on ABTS and DPPH. The inhibitory effects on LDL oxidation was evaluated by the formation of TBARS, REM and fragmentation of apolipoprotein B-100 (ApoB). Effects of herbal formulas on macrophage lipid accumulation were determined in native LDL and LPS co-incubated macrophages using Oil Red O staining. Results : The scavenging activities on ABTS and DPPH of herbal formulas were increased in dose-dependent manner (YDHST>YGSHT>CSYJT>TEJWT). Herbal formulas reduced the oxidation properties of LDL induced by $CuSO_4$. YDHST, YGSHT and CSYJT showed strong suppressive effect on LDL oxidation than TEJWT. In addition, YDHST, YGSHT and CSYJT significantly inhibited foam cell formation in LDL/LPS stimulated RAW 264.7 cells. Conclusions : These results demonstrate that YDHST, YGSHT and CSYJT have potentials on anti-atherosclerosis by antioxidative effect and suppressive effect on LDL oxidation.

• 한국분말재료학회지
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• 제22권4호
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• pp.271-277
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• 2015

As wrought stainless steel, sintered stainless steel (STS) has excellent high-temperature anti-corrosion even at high temperature of $800^{\circ}C$ and exhibit corrosion resistance in air. The oxidation behavior and oxidation mechanism of the sintered 316L stainless was reported at the high temperature in our previous study. In this study, the effects of additives on high-temperature corrosion resistances were investigated above $800^{\circ}C$ at the various oxides ($SiO_2$, $Al_2O_3$, MgO and $Y_2O_3$) added STS respectively as an oxidation inhibitor. The morphology of the oxide layers were observed by SEM and the oxides phase and composition were confirmed by XRD and EDX. As a result, the weight of STS 316L sintered body increased sharply at $1000^{\circ}C$ and the relative density of specimen decreased as metallic oxide addition increased. Compared with STS 316L sintered parts, weight change ratio corresponding to different oxidation time at $900^{\circ}C$ and $1000^{\circ}C$, decreased gradually with the addition of metallic oxide. The best corrosion resistance properties of STS could be improved in case of using $Y_2O_3$. The oxidation rate was diminished dramatically by suppression the peeling on oxide layers at $Y_2O_3$ added sintered stainless steel.

• Carbon letters
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• 제2권1호
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• pp.27-36
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• 2001

The pack-cementation process is the method which is formed SiC coating layer to improve weak oxidation properties of CFRCs (carbon fiber-reinforced carbons). This method develops the anti-oxidation coating layer having no dimensional changes and good wetting properties. In this study to improve the oxidative resistance of the prepared 4D CFRCs, the surface of CFRCs is coated by SiC using pack cementation method. The mechanical properties of SiC-coated 4D CFRCs are measured by the 3-point bending test, and their ablation properties are investigated by the arc torch plasma test. From the results, it is found that both mechanical and ablation properties of SiC-coated 4D CFRCs are much better than bare CFRCs.

• 열처리공학회지
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• 제16권6호
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• pp.335-340
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• 2003

To improve properties of wear resistance and anti-corrosion of the trivalent chromium platings, oxinitrocarbunsing and steam oxidation were conducted. Armophous trivalent Cr platings could be transformed to chromium carbides of high hardness, that showed low friction and wear rate. Even though micro-cracks were within as platings, superior anti-corrosion property was obtained by these treatments due to healing of cracks at the interface between the trivalent chromium platings and substrate.

• Composites Research
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• 제16권3호
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• pp.41-48
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• 2003

본 연구에서는 고온 산화분위기 하에서 탄소/탄소 복합재료의 내산화 특성 향상을 위해 사용된 이규화 몰리브덴(MoSi$_2$)의 함량(0. 4, 12. 그리고 20 wt%)에 따른 복합재료의 충격특성에 관하여 고찰하였다. 결과로서, MoSi$_2$가 함침된 탄소/탄소 복합재료는 이를 함유하지 않은 것에 비하여 충격특성 향상의 원인이 되는 탄소섬유와 매트릭스 수지간의 계면결합력 증가를 가져왔으며, 특히 12 wt% MoSi$_2$가 현재의 시스템에서 가장 우수한 충격특성을 나타내었다. 이는 복합재료 내의 탄소섬유, 필러, 그리고 매트릭스 수지간의 계면 접착력의 증가를 가져오는 90$0^{\circ}C$ 전후에서 MoSi$_2$의 취성­연성 전이(BDT) 작용 때문이라 사료된다.