• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2016.11a
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• pp.127-127
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• 2016

일반적인 알루미늄 표면처리 방식중 De Smut 는 질산 50~60% 용액에 상온에서 수초에서 수분 침적으로 Smut가 거의 제거가 되므로 도금공정에서 문제가 되지않았다. 단지 NOx 의 발생으로 작업공간 에서의 환경이 열악해 질 수 있다는 것이 문제 였다, 그러나 환경문제에 있어서 정부의 질소 규제 가 시작 되면서 알루미늄을 재료로 표면처리 하는 업체 에서는 질산 사용이 곤란해 해졌다. 그러나 질산이 금속과 의 친화력은 스테인레스, 알루미늄, 등 많은 금속에서 소지금속의 용해를 방지 하면서 산화스케일( De Smut)을 제거하는 데 유용한 산이어서 아직도 이용되고 있는 실정이다. 본 연구에서 는 우선 스테인레스 강의 산세시 불산과 질산의 혼산을 사용 하는 것을 불산, 불화암모늄, 황산, 과산화 수소 혹은 불산, 염산, 과산화 수소 등으로 전환 사용 하는 것 에 착안 하여 황산, 과산화수소 시스템에서 혹은 불산, 황산, 과산화 수소, 등으로 Smut 제거가 가능 한지 알아보고 그 효과를 살펴보았다.

• The Journal of Natural Sciences
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• v.4
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• pp.29-58
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• 1991

Ethanol은 섭취량에 따라 간 대사에 여러가지 영향을 미치는 것으로 알려져 있다. 과량의 ethanol 섭취가 유해한 것은 ethanol 그 자체보다는 산화과정에서 생성된 acetaldehyde와 과량의 수소(NADH)에 기인한다. 과량의 NADH는 간 세포의 화학적 평형을 저해하고 대사이상을 초래한다. 본 연구에서는 in vitro 뿐만 아니라 in vivo에서 alcohol dehydrogenase(ADH), aldehyde dehydroge-nase(ALDH), microsomal ethanol oxidizing system(MEOS)에 미치는 인삼 사포닌의 영향을 조사하고, 간에서의 수소 평형, 간에서의 $[1^(-14)C]$-ethanol의 분포, ethanol의 acetaldehyde와 lipid로의 전환 등을 관찰하였다. 인삼 사포닌은 상기 효소외에도 ethanol 대상에 관련된 다른 효소들의 활성을 증가시키는 것으로 관찰되었으며 이는 동물 체내로부터 acetaldehyde와 과량의 수소를 신속히 제거하는 것으로 사료된다.

• New & Renewable Energy
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• v.20 no.1
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• pp.175-181
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• 2024

This study analyzed the hydrogen conversion rate and microbial community in conjunction with changes in carbohydrate concentration during hydrogen fermentation using food waste, and presented comprehensive research results for the condition 80 g Carbo COD/L, which showed the highest efficiency with a carbohydrate removal rate of 98.1% and a hydrogen conversion rate of 1.76 mol H₂/mol. The microbial community analysis found that Clostridium sp., widely known as a hydrogen-producing microorganism, was released in 80 g Carbo COD/L and confirmed that it was a dominant species at 98.1%. Conversely, in 100 g Carbo. Under COD/L conditions, Leuconostoc sp. showed the maximun prevalence, which is believed to hinder hydrogen production.

• Applied Chemistry for Engineering
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• v.4 no.2
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• pp.335-341
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• 1993

In the conversion of methanol, the effect of acide property of heteropoly compounds on the catalytic activity was investigated. The pretreatment of Cu-exchanged 12-tungstophosphoric acid with hydrogen enhanced both the selectivity for propane and the conversion of methanol, and the pretreatment of Al-exchanged 12-tungstophosphoric acid with water enhanced the acid strength of the catalyst. The water added into the reactant decreased the conversion of methanol, while the pretreatment temperature did not affect it but the propylene/propane ratio. Various partially-substituted Al salts of 12-tungstophosphoric acid showed different catalytic activities depending on the degree of Al-substitution.

• Journal of Hydrogen and New Energy
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• v.12 no.4
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• pp.277-285
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• 2001

We developed a compact, 10 kWe, purifier-integrated reformer which supplies hydrogen for fuel cell vehicles. Our proprietary technologies regarding hydrogen purification by palladium alloy membrane and catalytic combustion by noble metal coated wire-mesh catalyst were combined with the conventional methanol steam reforming technology, resulting in higher conversion, excellent quality of product hydrogen, and better thermal efficiency than any other systems. In this system, steam reforming, hydrogen purification, and catalytic combustion take place all in a single reactor so that the whole system is compact and easy to operate. The module produces $8.2Nm^3/hr$ of 99.999% or higher purity hydrogen with CO impurity less than 10 ppm, which is equivalent to 10 kWe when PEMFC has 45 % efficiency. Thermal efficiency of the module is 81 % and the power density of the module is 1.6 L/kWe. As the results of experiments, cold-start time has been measured about 20 minutes. Response time of hydrogen production to the change of the feed rate has been within 1 minutes.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.29 no.6
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• pp.239-244
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• 2019

Two hydrogenation surface modifications, namely hydrogen atmosphere heat treatment and hydrogen plasma treatment, were found to lead to improved dispersion of nanodiamond (ND) seed particles and enhanced nucleation density for deposition of smooth ultrananocrystalline diamond (UNCD) film. After hydrogenation, the C-O and O-H surface functionalities on the surface of nanodiamond particles were converted to the C-H surface functionalities, and the Zeta potential was increased. As the degree of dispersion was improved, the size of nanodiamond aggregates decreased significantly and nucleation density increased dramatically. After hydrogen heat treatment at 600℃, average size of ND particles was greatly reduced from 3.5 ㎛ to 34.5 nm and a very high nucleation of ~3.9 × 10¹¹ nuclei/㎠ was obtained for the seeded Si surface.

• KSBB Journal
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• v.20 no.6
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• pp.393-400
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• 2005

Hydrogen($H_2$) as a clean, and renewable energy carrier will be served an important role in the future energy economy. Several biological $H_2$ production processes are known and currently under development, ranging from direct bio-photolysis of water by green algae, indirect bio-photolysis by cyanobacteria including the separated two stage photolysis using the combination of green algae and photosynthetic microorganisms or green algae alone, dark anaerobic fermentation by fermentative bacteria, photo-fermentation by purple bacteria, and water gas shift reaction by photosynthetic or fermentative bacteria. In this paper, biological $H_2$ production processes, that are being explored in fundamental and applied research, are reviewed.

• Applied Chemistry for Engineering
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• v.2 no.4
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• pp.363-371
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• 1991

The catalytic performance and availability of heteropoly compounds for the conversion of methanol to hydrocarbons have been studied. The effects of reaction conditions such as reaction temperature, methanol partial pressure and residence time and the effects of ion-exchange of the catalysts were examined for enhancing the yield of hydrocarbons and the selectivity of low olefins. Their acid strength depended on the kind of countercation, and the yield of hydrocarbons and the selectivity for propylene to propane were closely related to the electronegativity of the corresponding countercations. In contrast to the other heteropoly compounds, the ammonium salt showed a considerably high catalytic activity and a high selectivity for paraffins to low olefins.

• Applied Chemistry for Engineering
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• v.24 no.4
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• pp.337-343
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• 2013

Membrane reactors have been showing a promising future and attracted increasing attention in the scientific community as they possess advantages in terms of enhanced catalytic activity and selectivity, combination of processes (reaction and separation), simplicity in process design, and safety in operation. In particular, solid electrolyte membrane reactor principles are realized in fuel cells, electrolyzers and reactors for hydrogenation of carbon dioxide and other economically viable reactions. In this review, as a young generation of ion conducting materials, high temperature proton conductors are discussed in terms of the current status of material development and their various applications.

• Journal of the Korean Applied Science and Technology
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• v.24 no.4
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• pp.427-435
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• 2007

에너지원으로서 수소를 생산하기 위하여 하니컴 구조를 갖는 모노리스에 10 wt% $Ni/CeO_2-ZrO_2$ 촉매를 담지한 후 메탄의 수증기 개질 실험을 수행하였다. 다른 $CeO_2/ZrO_2$ 몰비를 갖는 촉매들 중에서, $Ni/CeO_2-ZrO_2(CeO_2/ZrO_2=4/1)$촉매가 $700-800^{\circ}C$에서 높은 메탄의 전환율을 보여 주었다. 10wt% $Ni/CeO_2-ZrO_2$ 촉매가 담지된 금속 모노리스 촉매체는 높은 열전도도와 비표면적들로 인하여 좋은 촉매 특성을 보여줌을 확인할 수 있었다. 또한, 금속모노리스 촉매체는 반응물에서 과다의 수증기에 의한 수소 수율에서 크게 영향을 받지 않음을 알 수 있었다. $GHSV=30,000h^{-1}$, 반응물 비$(H_2O/CH_4=3.0)$ 반응온도 $800^{\circ}C$에서 금속모노리스 촉매체는 98%이상의 메탄의 전환율을 보여주었다. 생성물 가스에서 $CO_2/CO$의 비는 수증기/메탄의 반응물비가 증가할수록 수성가스화 반응에 의하여 증가됨을 알 수 있었다.