• Bulletin of the Korean Chemical Society
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• v.13 no.6
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• pp.654-658
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• 1992

Photolysis of 1-phenyl-1,3,5-hexatriynes in deaerated tetrahydrofuran gave photoreduction and photoaddition products, while photolysis of 1-phenyl-1,3,5-hexatriynes in deaerated alcoholic solvents (methanol, i-propanol) yielded dark red products, probably oligomers or decomposition products of reactants, as exclusive major products. A plausible mechanism for the reaction is proposed.

• 한국연소학회:학술대회논문집
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• 2014.11a
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• pp.119-121
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• 2014

In general, high temperature combustion technique has been adopted as an efficient one. However, hydrocarbon-based fuel can be decomposed under high temperature, and it can affect the stabilization mechanism of edge flame. In this research, basic experimental study was conducted to identify the effect of fuel pyrolysis on the lift-off flame stabilization by changing the temperature of the plug flow reactor. Schmidt number of the gas fuel can be changed with temperature variation due to the fuel pyrolysis. Eventually, this study will help to establish and clarify the stabilization mechanism of lift-off edge flame.

• Laser Solutions
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• v.6 no.1
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• pp.33-40
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• 2003

The ablative decomposition mechanism of PMMA(polymethyl methacrylate) and PET(polyethylene terephthalate) with KrF excimer laser(λ : 248nm, pulse duration: 5㎱) is investigated. The UV/Vis spectrometer analysis showed that PMMA is a weak absorber and PET is a strong absorber at the wavelength of 248nm. The results(surface debris, melt, etch depth, etching shape) from drilling and direct writing experiments imply that ablation mechanism of PMMA is dominated by photothermal process, while that of PET is dominated by photochemical process.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1857-1860
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• 2003

The ablative decomposition mechanism of PMMA(polymethyt methacrylate), PET(polyethylene terephthalate) and PC(polycarbonate) with KrF excimer laser(λ: 248nm, pulse duration: 5ns) is investigated. The UV/Vis spectrometer analysis showed that PMMA is a weak absorber and PET, PC are a strong absorber at the wavelength of 248nm. The results(surface debris, melt, etch depth, etching shape) from drilling and direct writing experiments imply that ablation mechanism of PMMA is dominated by photothermal process, while that of PET, PC are dominated by photochemical process.

• Journal of the Korean institute of surface engineering
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• v.27 no.2
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• pp.83-90
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• 1994

We have investigated the mechanism for the abnormal oxide growth occuring during oxidation of the crystalline tungsten silicide. TEM and XPS analysis reveal the abnormaly grown oxide layer consisting of crystalline $Wo_3$ and amorphous $SiO_2$. The presence of crystalline $Wo_3$ provides a rapid diffusion of oxygen through the oxide layer. The abnormal oxide growth is mainly due to the poor quality of initial oxide layer growth on tungsten silicide. Two species such as tungsten and silicon from decomposition fo tungsten silicide as well as silicon supplied from the underlying polysilicon are the main contributors sto abnormal oxide forma-tion. Consequently, the abnormal oxidation results in the disintegration of tungsten silicide and thinning of polysilicon as well.

• Journal of the Korean Ceramic Society
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• v.35 no.3
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• pp.239-244
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• 1998

Iron complexes were prepared using ferric nitrate and ethylene glycol as starting materials and the ul-trafine ${\alpha}-Fe_2O_3$ particles with the sizes smaller than 200nm were obtained by the pyrolysis of iron com-plexes at over $350^{\circ}C$ In addition the decomposition mechanism of the synthesized iron complexes was in-vestigated by differential scanning calorimeter X-ray diffractometer and IR spectrometer. Transmission electron microscopy and BET method were performed to analyze the effects of ferric nitrate contents and reaction temperatures on the size and shape of the particles.

• Journal of the Korean Vacuum Society
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• v.5 no.4
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• pp.354-358
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• 1996

High indium incorporation was observed in InGaAs growth by precursor alternating metalorganic chemical vapor deposition (PAMOCVD). A possible mechanism of high indium incorporation into the crystal in PAMOCVD was proposed by considering the decomposition products of gallium and indium precursors, and thus the different adsorption behavior of the decomposed precursor molecules.

• Journal of Electrical Engineering and Technology
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• v.8 no.4
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• pp.813-823
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• 2013

On-line monitoring system is important for high voltage vacuum circuit breakers (HVCBs) in operation condition assessment and fault diagnosis. A distributed multilayer system with client/server architecture is developed on rated voltage 10kV HVCB with spring operating mechanism. It can collect data when HVCB switches, calculate the necessary parameters, show the operation conditions and provide abundant information for fault diagnosis. Ensemble empirical mode decomposition (EEMD) is used to detect the singular point which is regarded as the contact moment. This method has been applied to on-line monitoring system successfully and its satisfactory effect has been proved through experiments. SVM and FCM are both effective methods for fault diagnosis. A combinative algorithm is designed to judge the faults of HVCB's operating mechanism. The system's precision and stability are confirmed by field tests.

• 연구논문집
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• s.24
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• pp.81-96
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• 1994

To investigate failure mechanisms observed in carbon-phenolic thermal insulators, differential equations which govern the decomposition process in a deformable anisotropic porous solid are derived for three-dimensional axisymmetric constructions. The governing equations not only couple the material deformation with pore pressure, but also couple pressure and temperature, which means that heat convected by the pyrolysis gases is properly accounted for. Then the Bubnov-Galerkin finite element method is applied to these equations to transform them into a semidescrete finite element system. A thermal insulation liner in the cowl region under typical operating conditions is analyzed to find a mechanism for plylift. The results from the structural analysis show across-ply failure in the cowl zone. The mechanism for plylift is hypothesized as a sequential procedure : 1) the across-ply failure which is the precursor to plylift and 2) the local fiber buckling caused by generation of excessive in-plane compressive stress. To prevent plylift, the across-ply stress can be reduced by using appropriate material ply angles in cowl zone design.

• Bulletin of the Korean Chemical Society
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• v.21 no.5
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• pp.487-492
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• 2000

The combustion characteristics of a mixture of acetaldehyde, oxygen and argon behind a reflected shock wave at temperatures ranging from 1320 to 1897 K at 100 torr were studied. The emission from the OH radical at 306.4 nm and the pressure profile behind the reflected shock were measured to monitor ignition delay time. The ignition delay times were computed from a proposed mechanism of 110 elementary reactions involving 34 species. The simulation and sensitivity analysis confirm that the main channel for oxidation of acetaldehyde at high temperature consists of the Rice-herzfeld mechanism, the decomposition and oxidation of HCO, and the reaction of H with $O_2$.