• 한국연소학회:학술대회논문집
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• 한국연소학회 2012년도 제44회 KOSCO SYMPOSIUM 초록집
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• pp.267-268
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• 2012

Soot formation and oxidation characteristics of air-diluted propane diffusion flames have been experimentally investigated under the elevated pressure conditions. PAH concentrations showed more pressure sensitive behavior comparing to soot volume fractions. The flame/soot temperatures in soot oxidation region were obtained using the MOLLIP technique. Under the complete soot oxidation environment, the flame/soot temperature is increased with pressure. The increased temperature could accelerate the soot oxidation process and then exothermic oxidation reaction, in turn, could further raise the flame/soot temperature, which would result in the enhancement of soot oxidation process.

• Applied Microscopy
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• 제27권4호
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• pp.473-481
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• 1997

Disorder-order transformation of nanocrystalline FeAl have been investigated by a combination of electron and X-ray diffraction analysis including high resolution electron microscopy and differential scanning calorimetry. Fe-50at.%Al powders mechanically alloyed for 90 hours consist of $5\sim10$ nm size grains haying either disordered b.c.c. structure or amorphous structure. X-ray and electron diffraction of mechanically alloyed FeAl powders show that disorder-order transformation occurs at the temperature range of $300^{\circ}C\sim320^{\circ}C$. Such a low-temperature ordering behavior exhibiting an exothermic reaction is attributable to the nm-scale grain structure with a large amount of defects accumulated during mechanical alloying process.

• 한국안전학회지
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• 제3권2호
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• pp.49-53
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• 1988

The perovskite-type compounds $La_{1-x}Ca_xCoO_3$ were synthesized, their thermochemical properties and the gaseous sensitivity were investigated in ethanol vapor. The maximum response for detecting gas corresponded with the exothermic peak of DTA experiment. In any case the substituent was increased, the responsive ratio for detecting gas was grown upon. However, the needed time for response was later, and the operating temperature was elevated. The mechanism of this electrical conductivity was explained by the oxygen ionic diffusion through oxygen vacancy produced by the substituent.

• Bulletin of the Korean Chemical Society
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• 제22권4호
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• pp.367-371
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• 2001

Lithium inserted into artificial carbon has been synthesized as a function of the Li concentration. The characteristics of these prepared compounds were determined from the studies using X-ray diffraction(XRD), solid nuclear magnetic resonance (NM R) spectrophotometric and differential scanning calorimeter(DSC) analysis. X-ray diffraction showed that lower stage intercalation compounds were formed with increasing Li concentration. In the case of the AG3, most compounds formed were of the stage 1 structure. Pure stage 1 structural defects of artificial graphite were not observed. 7Li-NMR data showed that bands are shifted toward higher frequencies with increasing lithium concentration; this is because non-occupied electron shells of Li increased in charge carrier density. Line widths of the Li inserted carbon compounds decreased slowly because of nonhomogeneous local magnetic order and the random electron spin direction for located Li between graphene layers. The enthalpy and entropy changes of the compounds can be obtained from the differential scanning calorimetric analysis results. From these results, it was found that exothermic and endothermic reactions of lithium inserted into artificial carbon are related to the thermal stability of lithium between artificial carbon graphene layers.

• 한국추진공학회지
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• 제19권6호
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• pp.72-80
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• 2015

최근 기존의 통상적인 추진기관에서 새로이 공기 흡입 추진기관에 대한 관심이 커지고 있으며, 우리나라에서도 고체 램제트에 관한 기초 연구도 수행되는 등, 이 분야의 연구개발이 활발히 진행되고 있다. 고체 램제트의 연료에는 보론의 높은 열량 때문에 적용되고 있는데, 이 보론은 복잡한 연소 특성을 가지고 있어 이에 대한 연구도 많이 수행되어 오고 있다. 본 조사에서는, 램제트 연료 적용을 위하여 이러한 보론의 연소 특성을, 연구 개발되어 발표된 논문을 중심으로 하여 작성하였다.

• 한국자동차공학회논문집
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• 제16권2호
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• pp.80-86
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• 2008

Uncontrolled regeneration characteristics of two different type SiC DPFs(diesel particulate filters) were investigated by DPF test rig devised to facilitate DPF evaluation, especially for regeneration and MSL(maximum soot loading) test similar to engine dynamometer test. In order to estimate the limits of maximum filter temperature and temperature gradient causing filter fracture, such as crack or whitening, the temperature distributions inside the filter were measured by thermocouples. The maximum filter temperature was observed near the rear plane of central filter region due to heat accumulation by exothermic reaction of PM but the maximum temperature gradient occurred at the boundary of high filter temperature. These two parameters induced the different SiC DPFs to fracture with different modes, whitening and crack.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2006년도 제26회 춘계학술대회논문집
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• pp.327-330
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• 2006

기저연소과정이 포함된 젯추진을 고려한 기저유출 탄의 기저저항특성 조사를 위해 전산모사를 수행했다. 전반적인 유체역학과정은 2방정식의 $k-\omega$ SST난류 모델을 포함하고 반응유동을 위해 나비아-스토크방정식으로 모델화 되었다. 연소과정은 부분적으로 연소된 BBU (base-bleed unit) 출구조건을 갖는 유한속도반응으로 모델화 했다. 기저저항과 로켓플륨이 있는 기저유동의 상호작용에 대해 본 전산유체 해석기 능력을 보여주므로, 본 연구는 복합추진탄의 유체역학적 그리고 연소과정에 대한 이해를 준다.

• 한국추진공학회지
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• 제20권5호
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• pp.40-50
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• 2016

현재 적용되고 있는 에너지화 가소제는 $-NO_2$, $-ONO_2$ 및 $-N_3$와 같은 에너지화 활성 그룹을 포함하고 있어서 충격, 쇼크, 열 등 외부환경에 상당히 민감하여 복합화약의 둔감 안정성을 취약하게 한다. 본 연구에서는 민감한 에너지화 활성 그룹이 아니라 근본적으로는 비활성 그룹으로 복합화약의 민감도에는 영향을 미치지 않지만, 복합화약의 반응 시에 테르밋반응에 의해 추가적인 에너지를 발생할 수 있는 불소계 반응성 가소제를 적용한 폴리우레탄 결합제를 클릭반응으로 합성하고 나노 알루미늄과의 테르밋반응에 대한 열적 특성을 고찰하였다.

• 한국환경과학회지
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• 제21권6호
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• pp.705-711
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• 2012

Adsorption experiment of carbon dioxide was performed on MCM41 silica with a 30 wt.% EDA(ethylenediamine) loading at different $CO_2$ inlet concentration and various adsorption temperature. The surface characteristics of $CO_2$ capturing agent were carried out using BET analysis, X-ray diffraction and FT-IR. The results of BET showed 781 $m^2/g$ for MCM41 and 464 $m^2/g$ for EDA/MCM41. X-ray diffraction results reveled typical hexagonal pore system. The higher sorption capacity of EDA/MCM41 was about 80 $mg_{CO2}/g_{sorbent}$ with 50% $CO_2$ inlet concentration and 303 K adsorption temperature. The isosteric heat of adsorption in 303-353 K ranged from -25.47 to -28.24 KJ/mole for EDA/MCM41, which indicates $CO_2$-EDA/MCM41 interaction with exothermic adsorption process. Finally, the performance of EDA/MCM41 in 10 consecutive sorption-desorption runs was a stable with only a minor drop in its sorption capacity.

• 한국주조공학회지
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• 제15권6호
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• pp.566-573
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• 1995

In this study, the microstructural characteristics such as primary silicon, eutectic silicon, $SiC_p$ dispersion behavior, compound amount and Si solubility in $Al/SiC_p$ composite fabricated by the squeeze casting under various conditions were investigated systematically. As applied pressure(MPa) increases, cooling rate and compound amount are increased. In gravity casting, the cooling rate of hypereutectic composite is slower than of hypoeutectic composite by exothermic reaction of primary Si crystallization. But the cooling rate of hypereutectic composite is faster than that of hypoeutectic composite fabricated by same applied pressure, because amount of primary Si crystallization in hypereutectic composite was decreased, on the contrary, primary ${\alpha}-Al$ in hypoeutetic composite was increased due to increase of Si solubility in matrix by applied pressure. The crystalized primary silicon in hypereutectic composite fabricated by squeeze casting become more fine than that in non-pressure casting This is because mush zone became narrow due to increase of Si content of eutectic composition by pressure and time for growth of primary silicon got shorter according to applied pressure. It is turned out that eutectic temperature and liquidus are decreased by the increasing of squeeze pressure in all the composite due to thermal unstability of matrix owing to increasing of Si solubility in matrix by the increasing of applied pressure, as indicated in thermal anaiysis(DSC) results.