• ETRI Journal
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• 제34권5호
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• pp.713-718
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• 2012

Sensor nodes in ubiquitous sensor networks require autonomous replacement of deteriorated gas sensors with reserved sensors, which has led us to develop an encapsulation technique to avoid poisoning the reserved sensors and an autonomous activation technique to replace a deteriorated sensor with a reserved sensor. Encapsulations of $In_2O_3$ nanoparticles with poly(ethylene-co-vinyl alcohol) (EVOH) or polyvinylidene difluoride (PVDF) as gas barrier layers are reported. The EVOH or PVDF films are used for an encapsulation of $In_2O_3$ as a sensing material and are effective in blocking $In_2O_3$ from contacting formaldehyde (HCHO) gas. The activation process of $In_2O_3$ by removing the EVOH through heating is effective. However, the thermal decomposition of the PVDF affects the property of the $In_2O_3$ in terms of the gas reactivity. The response of the sensor to HCHO gas after removing the EVOH is 26%, which is not significantly different with the response of 28% in a reference sample that was not treated at all. We believe that the selection of gas barrier materials for the encapsulation and activation of $In_2O_3$ should be considered because of the ill effect the byproduct of thermal decomposition has on the sensing materials and other thermal properties of the barrier materials.

• 한국응용과학기술학회지
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• 제24권4호
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• pp.347-353
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• 2007

Fleshing scrap is a kind of wastes produced during leather making process and used in the test of manufacturing biodiesel. The early step of manufacturing biodiesel is fat recovery from fleshing scrap. Hence, we investigated the influence of the way of fat recovery on the fatty acid composition. We used three different recovery ways, that is chemical method by protein decomposition with acid/fat recovering, physical method by protein denaturalization with heat and vacuum/fat pressing, and biodiesel method by protein decomposition/fat recovering. The biological method yielded the best results in terms of appearance transparency. It was most effective to lower acid value. Also the recovered fat by biological method would be favorable methyl-ester reaction raw material for biodiesel because it contains more than 5% of oleic acid among unsaturated fatty acid.

• 한국재료학회지
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• 제28권1호
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• pp.24-31
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• 2018

This study reports an environment-friendly synthetic strategy to process nickel oxide nanocrystals. A mesoporous nickel oxide nanostructure was synthesized using an environmentally benign biomimetic method. We used a natural rambutan peel waste resource as a raw material to ligate nickel ions to form nickel-ellagate complexes. The direct decomposition of the obtained complexes at $700^{\circ}C$, $900^{\circ}C$ and $1100^{\circ}C$ in a static air atmosphere resulted in mesoporous nickel oxide nanostructures. The formation of columnar mesoporous NiO with a concentric stacked doughnuts architecture was purely dependent on the suitable direct decomposition temperature at $1100^{\circ}C$ when the synthesis was carried out. The prepared NiO nanocrystals were coated on cotton fabric and their antibacterial activity was also analyzed. The NiO nanoparticle-treated cotton fabric exhibited good antibacterial and wash durability performance.

• 대한환경공학회지
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• 제27권8호
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• pp.829-836
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• 2005

본 연구에서는 광화학적 산화처리에 의한 아트라진의 분해특성을 분해산물의 분석을 통하여 살펴보았다. 본 실험에서 나타난 주요 분해산물로는 OIET, OIAT, OAAT가 있었고, 이를 통하여 광산화 반응에 의한 아트라진의 주분해반응은 dechlorination과 hydroxylation임을 확인할 수 있었다. TOC의 분석 결과 광산화에 의한 아트라진의 무기화는 기대하기 어려운 것으로 판명되었으며, 염소 이온의 물질수지 분석을 통해 본 광산화 반응에 의해 아트라진의 염소기의 완전한 탈염소가 진행되었음을 알 수 있었다.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2007년도 제28회 춘계학술대회논문집
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• pp.102-105
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• 2007

본 연구에서는 과산화수소 분해 반응을 이용한 초소형 추력기에 대한 성능 평가 실험을 수행하였다. 촉매 베드로는 질량 대 면적 비가 큰 다공성의 세라믹 물질($Isolite^{(R)}$)을 사용하였다. 14%wt의 백금이 촉매로서 촉매 베드에 코팅되었고, 단일추진제로는 85% 과산화수소를 사용하였다. 촉매 베드의 길이와 과산화수소의 가압 압력을 변수로 정하였다. 모든 실험은 콜드 스타트 조건에서 30초간 수행되었다. 매 실험마다 압력을 측정하여 $c^*$ 효율을 계산하였다. 촉매 베드의 길이가 30 mm이고 가압압력이 5.51 bar일 때 95% 이상의 만족스러운 $c^*$ 효율을 보였다.

• Bulletin of the Korean Chemical Society
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• 제34권11호
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• pp.3420-3424
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• 2013

The reaction of $LnCl_3{\cdot}7H_2O$ [Ln = La (1), Ce (2)] with salicylic acid (HL) and 1,10-phenanthroline (Phen) at $20^{\circ}C$ in $H_2O$/ethanol gave after work-up and recrystallization two novel lanthanide complexes with general formula $[Ln(Phen)_2(L)_3(HL)]{\cdot}H_2O$. Compounds 1 and 2 were characterized by IR and UV-Vis spectroscopy, TGA, CHN as well as by X-ray analysis. According to these results, compounds 1 and 2 are isostructural and contain $Ln^{3+}$ ions with coordination number nine. Complexes 1 and 2 consist of two Phen, one neutral HL and three L anions (two L anions act as monodentate ligands and the third one is chelating to $Ln^{3+}$). Thermal decomposition led to primary loss of the Phen molecules. Then HL molecules and finally L moieties left the material to give $Ln_2O_3$.

• Journal of Microbiology and Biotechnology
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• 제26권8호
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• pp.1404-1408
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• 2016

In recent years, foot-and-mouth disease has occurred in all parts of the world. The animals with the disease are buried in the ground; therefore, their concentration could affect ground or groundwater. Moreover, the complete degradation of carcasses is not a certainty, and their disposal is important to prevent humans, livestock, and the environment from being affected with the disease. The treatment of Corynebacterium glutamicum is a feasible method to reduce the risk of carcass decomposition affecting humans or the environment. Therefore, this study aimed to investigate the effect of C. glutamicum on the soil environment with a carcass. The composition of amino acids in the soil treated with C. glutamicum was generally higher than those in the untreated soil. Moreover, the plant root in the soil samples treated with C. glutamicum had 84.0% amino acids relative to the standard value and was similar to that of the control. The results of this study suggest the possibility to reduce the toxicity of a grave land containing animals with this disease.

• 한국재료학회지
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• 제26권2호
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• pp.95-99
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• 2016

In this study, 5 um sized $ZrSiO_4$ was ground to 1.9 um, 0.3 um, and 0.1 um sized powders by wet high energy milling process, and the sintering characteristics were observed. Pure $ZrSiO_4$ itself can-not be sintered to these levels of theoretical density, but it was possible to sinter $ZrSiO_4$ powder of nano-scale size of, -0.1 um to the theoretical density and to lower the sintering temperature for full density. Also, the decomposition of $ZrSiO_4$ with a size in the micron range resulted in the formation of monoclinic $ZrO_2$; however, in the nano sized range, the decomposition resulted in the tetragonal phase of $ZrO_2$. So, it was possible to improve the sintering characteristics of nano-sized $ZrSiO_4$ powders.

• 열처리공학회지
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• 제34권2호
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• pp.53-59
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• 2021

Due to high specific strength and low density, AZ series magnesium alloys have been receiving high interest as a lightweight material. However, their industrial application is limited due to the phenomenon that the strength decreases at elevated temperature by the occurrence of softening effect because of the Mg17Al12 phase decomposition. To solve this problem, many research were conducted to increase the high-temperature strength by forming a thermal stable second-phase component by adding new elements to the AZ magnesium. Especially, adding Ca to AZ magnesium has been reported that Ca forms the new second-phase. However, studies about the analysis of decomposition or precipitation temperature, formation composition, and components to understand the formation behavior of these precipitated phases are still insufficient. Therefore, the effect of Ca addition to AZ61 on the phase change and microstructure of the alloy during annealing was investigated. As a result of analysis of the initial and heat-treated specimen, AZ61 formed α-Mg matrix and precipitated phase of Mg17Al12, and AZX611 formed one more type of precipitated phase, Al2Ca. Also, Al2Ca was thermal stable at high temperatures. And after annealing, the laves phase was decomposed to under 10 ㎛ size and distributed in matrix.

• 대한환경공학회지
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• 제28권3호
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• pp.316-322
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• 2006

본 연구의 목적은 환경담배연기를 대표하는 주요 오염물질 중에 하나인 니코틴의 분해를 위해서 산화티타늄 광촉매를 적용할 수 있는지 여부에 대하여 기술적 평가하는 것이다. 광촉매로 코팅된 건축자재를 이용하여 니코틴을 분해하는 정도를 평가하기 위하여 네 개의 기초 실험을 수행하였다. 니코틴의 광촉매 분해와 관련된 다음의 다섯 변수를 조사하였다: 코팅 타일의 건조조건, 코팅 졸의 종류, 코팅횟수, 상대습도, 그리고 초기농도. 변수 시험에 앞서, 실험장치에 대한 니코틴의 흡착 여부를 평가하였다. 본 연구에서 조사된 변수 모두가 니코틴의 광산화분해능에 영향을 미치는 것으로 나타났다. 낮은 온도와 긴 건조시간 조건과 비교할 때 높은 온도와 짧은 건조시간 조건에서 건조된 타일에서 보다 높은 니코틴 분해효율을 나타내었다. ST-KO3 졸로 코팅된 타일이 E-T 졸로 코팅된 타일 보다 높은 분해효율을 나타내었다. 코팅횟수가 증가할수록 광산화분해가 잘 일어났다. 높은 상대습도와 낮은 유입농도 조건에서 광산화분해가 잘 일어났다. 결과적으로, 환경담배연기에 포함된 니코틴을 광촉매로 코팅된 건축자재를 적용할 때에는 본 연구에서 평가된 다섯 가지 변수가 모두 고려되어야함이 제안되었다.