• Journal of Korean Society for Atmospheric Environment
• /
• v.23 no.E1
• /
• pp.10-15
• /
• 2007

The gas hydrates are probably most sensitive to climate change since they are stable only under specific conditions of high pressure and low temperature. One of the main factors responsible for formation of gas hydrates is the saturation of the gases with water vapor. Quantitative phase equilibrium data and understanding of the roles of water component in the phase behavior of the heterogeneous water-hydrocarbon-hydrate mixture are of importance and of engineering value. In this study, the water content of ethylene gas in equilibrium with hydrate and water phases were analyzed by theoretical and experimental methods at temperatures between 274.15 up to 291.75 K and pressures between 593.99 to 8,443.18 kPa. The experimental and theoretical enhancement factors (EF) for the water content of ethylene gas and the fugacity coefficients of water and ethylene in gas phase were determined and compared with each other over the entire range of pressure carried out in this experiment. In order to get the theoretical enhancement factors, the modified Redlich-Kwong equation of state was used. The Peng-Robinson equations and modified Redlich-Kwong equations of state were used to get the fugacity coefficients for ethylene and water in the gas phase. The results predicted by both equations agree very well with the experimental values for the fugacity coefficients of the compressed ethylene gas containing small amount of water, whereas, those of water vapor do not in the ethylene rich gas at high temperature for hydrate formation locus.

• 한국연소학회:학술대회논문집
• /
• 2000.12a
• /
• pp.229-235
• /
• 2000

Soot formation characteristics in counterflow diffusion flames of ethylene/propane/nitrogen mixtures have been studied experimentally to investigate the soot formation mechanism. The effect of HACA reaction on PAH and soot growth has been experimentally investigated by using 2-D planar LII and PAH LIF techniques.

• 한국연소학회:학술대회논문집
• /
• 2003.05a
• /
• pp.137-142
• /
• 2003

In order to investigate the effect of fuel mixing on PAH and soot formation, four species of methane, ethane, propane and propene have been mixed in counterlfow ethylene diffusion flame. Laser-induced incandescene and laser-induced fluorescene techniques were employed to measure soot volume fraction and polycyclic aromatic hydrocarbon (PAH) concentration, respectively. Results showed that the mixing of ethane (or propane) in ethylene diffusion flame produces more PAHs and soot than those of propene, even though the propene diffusion flame produces more PAHs and soot than that of propane and ethane. Considering that propene directly dehydrogenates to propargyl radical, this behavior implied that the enhancement of PAH and soot formation by the fuel mixing of ethylene and ethane (or propane) cannot be explained by propargyl radical directly dehydrogenated from ethane (or propane).

• Proceedings of the Korean Fiber Society Conference
• /
• 2001.04b
• /
• pp.91-94
• /
• 2001

• Bulletin of the Korean Chemical Society
• /
• v.22 no.3
• /
• pp.261-262
• /
• 2001

• The Korean Fashion and Textile Research Journal
• /
• v.10 no.2
• /
• pp.254-259
• /
• 2008

Poly(ethylene-co-vinylacetate)(EVA) microspheres were prepared by a thermally induced phase separation. The microsphere formation occurred by the nucleation and growth mechanism in the metastable region. The diluents used were toluene. The microsphere formation and growth was followed by the cloud point of the optical microscope measurement. The microsphere size, which was obtained by SEM observation and particle size analyzer, became decreased when the titanium dioxide($TiO_2$) concentration was higher. The deodorizing function of the prepared fabrics was studied by the determination of the decomposing capability for $NH_3$. The deodorant activity of these deodorizing fabrics was measured by chromogenic gas detector tubes. The deodorant activity of $NH_3$ increased with increasing $TiO_2$ concentration of EVA microsphere.

• Journal of the Korean Chemical Society
• /
• v.30 no.5
• /
• pp.456-464
• /
• 1986

The complex formation of branched poly(ethylene imine) (BPEI) with bivalent transition metal ions, such as Fe(II), Co(II), Ni(II) and Cu(II), have been investigated in terms of visible absorption and pH titration methods in an aqueous solution in 0.1M KCl at 30${\circ}$. The stability constants for M(II)-BPEI complexes was calculated with the modified Bjerrum method. The formation curves of M(II)-BPEI complexes showed that Fe(II), Co(II), Ni(II) and Cu(II) ions formed coordination compounds with four, two, two, and two ethylene imine group, respectively. In the case of Cu(II)-BPEI complex at pH 3.4 ∼ 3.8, ${\lambda}_{max}$ was shifted to the red region with a decrease in the acidity. The overall stability constants (log $K_2$) increased as the following order, Co(II) < Cu(II) < Ni(II) < Fe(II).

• Horticultural Science & Technology
• /
• v.33 no.3
• /
• pp.356-363
• /
• 2015

This study examined the effects of different day/night temperature regimes or silver ion on growth and flowering of passion fruit 'Tai-nung No.1'. Low temperature treatment ($20/15^{\circ}C$) caused passion fruit cultivar 'Tai-nung No.1' to fail to flower. Flowering induction occurred within a temperature range of $20-30^{\circ}C$, with no significant difference in the days to first flower bud and the total number of flower buds between plants grown at $30/25^{\circ}C$ and $25/20^{\circ}C$. However, plants grown at $30/25^{\circ}C$ exhibited their first flower buds set on the higher nodes and had higher abortion rates of flower buds than those at $25/20^{\circ}C$. Plants grown at $30/25^{\circ}C$ had the most rapid growth and the shortest plastochron. We also evaluated the effect of the ethylene response inhibitors silver nitrate ($AgNO_3$) and silver thiosulfate (STS) on growth and flowering of potted passion fruit 'Tai-nung No.1', when they were exposed to low temperature conditions ($20/15^{\circ}C$) following chemical treatments ($AgNO_3$ or STS, at 0.5 or 1.0 mM). $AgNO_3$ and STS treatments induced flower formation and initial flower bud formation within approximately two weeks at $20/15^{\circ}C$ whereas non-treated control plants exhibited no flower formation. ACC content and activity of ACC oxidase in the leaves of passion fruit 'Tai-nung No.1'exposed to low temperature conditions ($20/15^{\circ}C$) were significantly inhibited by the ethylene inhibitor treatments. These results indicate that ethylene, which is produced under low temperature conditions, plays an important role in inhibiting flower formation in passion fruit.

• 한국신재생에너지학회:학술대회논문집
• /
• 2005.06a
• /
• pp.618-621
• /
• 2005

In this study, the phenomena of hydrate formation and inhibition were investigated according to varying the concentrations using methanol and ethylene glycol as chemical additives. The results reveal that the used additives display better inhibition effects compared to pure water by decreasing the formation temperature and the inhibition performance of methanol is superior to that of ethylene glycol. As a conclusion, the plugging phenomena of flowline in natural gas product ion. subsea and frozen field pipelines can be predicted by examining the hydrate formation and inhibition conditions. Specifically, the results of this study can be applied to the selection of the prevention criteria and method of hydrate formation.

• The Korean Fashion and Textile Research Journal
• /
• v.10 no.3
• /
• pp.371-376
• /
• 2008

Poly(ethylene-co-vinylacetate) (EVA) microspheres were prepared by thermally induced phase separation (TIPS) in toluene. The microsphere formation occurred by the nucleation and growth mechanism in metastable region. The effects of the concentration and component of the polymer and cooling rate on microsphere formation were investigated. The microsphere formation and growth were followed by the cloud point of the optical microscope measurement. The microsphere size distribution, which was obtained by particle size analyzer, became broader when the polymer concentration was higher, the content of vinyl acetate in EVA copolymer was higher, the cooling rate of EVA copolymer solution were lower. The content of disperse dye in EVA microsphere was obtained by TGA thermal analysis, the dye content of EVA15 and EVA18 were 3.5 and 2.0 wt% respectively.