• 한국식품과학회지
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• 제52권1호
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• pp.46-53
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• 2020

Carrots were deep fat fried with sunflower oil (SO), palm oil (PO), and a blend of palm and sunflower oils (PSO with PO:SO as 2:8 or 4:6) at different temperatures (180 and 190℃) and lengths of time (0.5 to 2.5 min). The quality of deep fat fried carrots was determined by the moisture and fat content, color, conjugated dienoic acid (CDA), hydroperoxide, p-anisidine value, and fatty acid composition. The moisture content of fried carrots decreased with increasing frying time, while the fat content increased. The CDA and p-anisidine values of carrots fried with SO were higher than those fried with PO because of greater unsaturated fatty acids content in SO. PSO was a better choice than SO or PO for deep fat frying carrots in the aspects of oxidative stability and ratio of unsaturated to saturated fatty acids. These results indicate that the quality of deep fat fried carrots depends on the type of oil and frying temperature used, as well as the length of time.

• 청정기술
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• 제16권2호
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• pp.132-139
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• 2010

서로 다른 몰비의 Cu-Mn 혼합산화물을 공침법으로 제조하여 $30^{\circ}C$에서 CO 산화반응을 수행하였다. 제조된 촉매는 CO 산화반응에서 반응 활성과 연관시키기 위하여 XRD, $N_2$ 흡착 및 탈착, XPS, $H_2-TPR$ 등의 특성분석을 수행하였다. 제조된 촉매의 질소흡착 등온곡선은 4형태로 7-20 nm크기의 세공이 존재하며, Mn의 함량이 증가함에 따라 BET 표면적은 17에서 $205m^2{\cdot}g^{-1}$ 으로 증가하였다. XPS 분석으로 Cu-Mn 혼합산화물 상의 Cu는 주성분이 2+의 산화상태임을 확인하였고, Mn은 +3과 +4의 산화 상태를 나타냈다. Cu-Mn 촉매의 함량 및 비율에 따른 최적 활성을 실험 조사한 결과, $30^{\circ}C$의 반응온도에서 Cu/(Cu+Mn)의 몰비가 0.5일 때 가장 좋은 활성을 나타냈으며, 이를 기준으로 화산형 형태의 반응 곡선을 나타냈다. 수분 존재하의 CO 산화반응은 활성점에 수분과 CO의 경쟁흡착으로 촉매의 활성을 감소시켰으며 최종적으로는 활성금속 성분과 하이드록실 그룹을 형성하였기 때문이다.

• 한국표면공학회지
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• 제27권1호
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• pp.45-53
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• 1994

A kinetic study on the electrodeposition of zinc-iron alloys onto a steel in chloride solutions has been car-ried out using a rotating disc geometry. The results show that the deposition rate was increased with electropotential, disc rotation speed and temperature, and consequently the rate was partly controlled by elec-trochemical reaction and partly by mass transport. The iron content of deposit was more increased with cell voltage than with disc rotating speed and temperature. During electrodeposition process, the addition of metal-lic zinc powder retards oxidation rate of $Fe^{2+}$.

• 한국대기환경학회지
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• 제33권1호
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• pp.64-74
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• 2017

In this study, we have analyzed relationship between the measured Water Soluble Organic Carbon (WSOC) concentrations and the estimated aerosol water content of $PM_{10}$ (particulate matter with an aerodynamic diameter of less than or equal to $10{\mu}m$) for the period between September 2006 and August 2007 at Seoul, Korea. Water content of $PM_{10}$ was estimated by using a gas/particle equilibrium model, Simulating composition of Atmospheric Particles at Equilibrium 2 (SCAPE2). The WSOC concentrations showed low correlation with Elemental Carbon (EC), but Water Insoluble Organic Carbon (WISOC) were highly correlated with EC. It seemed that hydrophilic groups were produced by secondary formation rather than primary formation. As with the previous studies, WSOC showed good correlation with secondary ions ($NO_3{^-}$, $SO_4{^{2-}}$, $NH_4{^+}$), especially WSOC was highly correlated with $NO_3{^-}$ that is a secondary ion formed by photochemical oxidation from more local sources than $SO_4{^{2-}}$. No apparent correlation between the measured WSOC and estimated water content was observed. However, WSOC showed good correlation with estimated water content when it was assumed that relative humidity was higher than the deliquescence relative humidity of the system. In conclusion, WSOC is correlated with water content by hygroscopic ions and it is expected that nitrate play an important role among the water content and WSOC.

• 동아시아식생활학회지
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• 제27권3호
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• pp.304-312
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• 2017

This study was carried out to evaluate the effects of yam powder addition (0~40%) on the quality characteristics and oxidative stability of yackwa made with rice flour. While most rice flour (34.35%) had a particle size more than $250{\mu}m$, 75% of yam powder had a particle size less than $65{\mu}m$. Width, height, and volume of rice yackwa added with yam powder increased with increasing yam powder content. While L and b values of rice yackwa added with yam powder decreased with increasing yam powder content, a value increased. Hardness and chewiness of rice yackwa added with yam powder increased as storage period increased at $25^{\circ}C$ for 9 days, whereas they decreased with increasing yam powder content. In a discrimination test, brown color, flavor, sweetness, and bitterness increased with increasing yam powder content, whereas hardness decreased. In a preference test, taste, texture, and overall acceptance increased with increasing yam powder content. The acid and thiobarbituric acid (TBA) values of rice yackwa added with yam powder increased as storage period increased. However, acid and TBA values of the treated groups decreased with increasing yam powder content compared to the control group. Although 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical scavenging activities decreased with increasing storage period, values increased with increasing yam powder content. It was found that yackwa quality, preference, and oxidative stability increased during storage with increasing yam powder content. From these results, addition of 40% yam powder would be the optimal conditions for making rice yackwa.

• 한국자원식물학회지
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• 제26권5호
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• pp.628-635
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• 2013

국내에 자생하는 기름생산이 가능한 목본식물의 바이오디젤 원료로서의 이용가능성을 구명하기 위해 기름함량, 지방산 조성 및 전이에스테르화를 통해 생산된 바이오디젤의 특성분석을 실시하였다. 목본 기름식물의 종자 내 기름함량은 15.1 ~ 70.3%로 다양하였으며, 지방산조성은 주로 올레산, 리놀레산, 리놀렌산, 팔미트산 및 스테아르산 등 이였으며 올레산의 함량이 가장 높았고 모든 식물에서 불포화지방산이 포화지방산보다 많았다. 지방산메틸에스테르의 산화안정성은 2.25 ~ 8.62 hours/$110^{\circ}C$로 나타났고, 요오드가는 때죽나무 기름이 가장 높았으며 이는 불포화지방산의 함량이 다른 식물 종보다 높기 때문이다. 저온 필터막힘점은 $0^{\circ}C$ to $-13^{\circ}C$로 다양하게 나타났으며 이팝나무 지방산메틸에스테르가 저온유동성이 가장 우수하였다. 기름함량, 지방산조성, 바이오디젤 특성 등을 종합하였을 때 동백나무, 이팝나무 및 때죽나무의 종자에서 추출한 기름이 바이오디젤로의 이용 가능성이 비교적 높은 것으로 생각된다.

• 한국분말재료학회지
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• 제16권6호
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• pp.403-409
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• 2009

Plasma spray forming is recently explored as a near-net-shape fabrication route for ultra-high temperature metals and ceramics. In this study, monolithic tungsten has been produced using an atmospheric plasma spray forming and subsequent high temperature sintering. The spray-formed tungsten preform from different processing parameters has been evaluated in terms of metallurgical aspects, such as density, oxygen content and hardness. A well-defined lamellae structure was formed in the as-sprayed deposit by spreading of completely molten droplets, with incorporating small amounts of unmelted/partially-melted particles. Plasma sprayed tungsten deposit had 84-87% theoretical density and 0.2-0.3 wt.% oxygen content. Subsequent sintering at 2500$^{\circ}C$ promoted the formation of equiaxed grain structure and the production of dense preform up to 98% theoretical density.

• Tribology and Lubricants
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• 제27권5호
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• pp.275-280
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• 2011

Automotive wheel bearing grease helps to reduce stresses and prevent wear of wheel bearings. But it is easily contaminated by water and other contaminants. In this study, we investigated the property change of automotive wheel bearing grease under water contamination. The result showed that some properties such as dropping point, work penetration and oxidation stability were not influenced by water content. However, most of properties such as work stability, water washout characteristics, leakage tendency, oil separation, evaporation loss and rust protection became worse after water was added. This is thought that added water makes the interaction weak between thickener and base oil of grease.

• KSBB Journal
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• 제13권3호
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• pp.279-283
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• 1998

To investigate the feasibility of the microbial process for removal of heavy metals from the high solid content sludge, the effect of sludge concentration on the solubilization of heavy metals by an iron oxidizing bacterium Thiolbacillus ferrooxidans was examined. With increasing the sludge concentration, the removal efficiency of heavy metals and the oxidation rate of iron were inhibited. Especially, when the sludge concentration is over 5% (w/v), the activity of T. ferrooxidans was remarkably inhibited. This inhibition is considered to occur due to the dissolved inhibitory materials such as organic compounds, heavy metals, and others which were extracted from the sludge during incubation period. In conclusion, the microbial process by T. ferrooxidans is only effectively used in ranges of 1.3 to 4.0% (w/v) sludge concentration.

• Carbon letters
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• 제10권1호
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• pp.5-8
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• 2009

We measured the non-carbon content of single-walled carbon nanotubes (SWCNTs) in SWCNT soot using thermogravimetric analysis. The weight increased percentage by the oxidation of metal in the raw soot is well obtained by TGA graph which was confirmed with ICP-AES, XRD, and XPS. This work will be very useful for the purity precise evaluation of SWCNT with UN-vis-NIR spectroscopy.