• Transactions of the Korean Society of Mechanical Engineers B
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• v.30 no.12 s.255
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• pp.1188-1195
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• 2006

This paper examines the critical air temperature at which frost formation does not occur on a cold plate in order to improve the efficiency of a heat pump. The critical air temperature on test points is obtained from numerical analysis and a correlation of the critical air temperature is derived as a function of frosting factors (air absolute humidity, air velocity, and cold plate temperature) by least square method. Experiments are carried out to verify the correlation proposed in this study, and the prediction obtained with the correlation agrees well with the experimental data. Based on the correlation, we propose the non-frosting regions according to frosting factors.

• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.2
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• pp.173-182
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• 1997

The instantaneous flame temperature and soot formation and oxidation in a D. I. diesel engine are measured by using a two-color method. The proposed method based on the continuous spectral radiation from the soot particles in flames is applicable to industrial diesel engines without major modifications of their main characteristics. Measurements are performed at one location inside the combustion chamber of a D.I. diesel engine. Effects of different engine speeds and loads on flame temperature and KL factor which is an index of soot concentrations were examined. A little temperature change were observed with increasing engine speed, while increased with loads. The higher the flame temperature is, the lower the KL factor is.

• Journal of Mushroom
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• v.13 no.3
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• pp.223-227
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• 2015

The study was conducted to investigate the effects of post-incubation period and temperature treatment conditions during incubation on the uniform primordia formation and cultural characteristics of oyster mushroom (Pleurotus ostreatus). Three kinds post-incubation period; 25, 30, 35 days and control were applied for 30 days while two kinds incubation room temperature $23^{\circ}C$ and $26^{\circ}C$ and control were used $20^{\circ}C$. The substrate temperature during pre-incubation was of 'Suhan No. 1' and 'Gonji No. 7'. Oyster mushroom varieties tended to increase between $24^{\circ}C$ to $26^{\circ}C$ at 11 to 15 days after inoculation and then they were maintained in treatment temperature during post -incubation period. The $CO_2$ occurrence was at the highest at 6,500 ppm for 'Suhan No. 1' and 5,800 ppm for 'Gonji No. 7' at the time of the highest temperature increase. The ratio of un-uniformal primordia formation and the ratio of non-commercial fruit body were reduced by 40%, 10.5%, respectively compared to control for 'Suhan No. 1' when in the post-incubation temperature was $26^{\circ}C$, and incubated for 10 days and 15 days treatment. Also, 'Gonji No. 7' was reduced by 19%, 9.5%, respectively when in the post-incubation temperature was $26^{\circ}C$, and incubated for 10 days treatment. Therefore, the higher post-incubation temperature of room and longer post-incubation period resulted in the higher percentage of primordia formation of two cultivars.

• 한국연소학회:학술대회논문집
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• 2014.11a
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• pp.339-342
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• 2014

Rotary kiln produces lime from limestone through thermal decomposition. Ring formation in kiln internal wall is known issue that decreases productivity. The cause of ring formation is temperature imbalance as flame leans toward upper wall. Therefore, burner nozzle geometry was changed to improve air-fuel mixing state which leads to prevention of ring formation. CFD simulation and experimental test were performed in this study to investigate the effect of air-fuel mixing on flame structure, temperature and $NO_X$ concentration. It is shown that combustion efficiency has been enhanced and $NO_X$ concentration has been decreased by using swirl flow for secondary combustion air. It's also shown that flame has been straightened by using straight flow for secondary combustion air.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.28A no.11
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• pp.887-893
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• 1991

To take advantage of Ti-polycide, when it is contacted with both n+ and p+ active area of silicon, the effects of BF$_2$ on the formation of Ti-silicide were investigated with RTA temperature and dopant concentration. The intermediate phase C49 TiSi$_2$ appeared at $650^{\circ}C$ and the stable phase C54 TiSi2 was formed at $700^{\circ}C$. And the formation of Ti-silicide was hindered by BF$_2$ doping and this trend was decreased with increasing temperature. The out-diffusion phenomena of BF$_2$ into Ti silicide were not observed. And significantly, the native oxide was a chief factor preventing the formation of Ti-silicides.

• Ocean and Polar Research
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• v.26 no.3
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• pp.515-521
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• 2004

The processes of formation and dissociation of gas hydrates were investigated by monitoring pressure and temperature variations in a pressure cell in order to understand the kinetic behavior of gas hydrate and the controlling factors fur the phase transition of gas hydrate below freezing. Gas hydrates were made kom guest gases ($CH_4,\;CO_2$, and their mixed-gas) and fine ice powder. We found that formation and dissociation speeds of gas hydrates were not controlled by temperature and pressure conditions alone. The results of this study suggested that pressure levels at the formation of mixed-gas hydrate determine the transient equilibrium pressure itself.

• 한국가시화정보학회:학술대회논문집
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• 2003.11a
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• pp.107-110
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• 2003

Characteristics of PAH and soot formation in coflow diffusion flames of methane, methane, propane, and ethylene have been experimentally studied to investigate the temperature and fuel structure effect on soot formation. PAH and soot images were acquired by applying PAH LIF and LII techniques, respectively and temperature was measured using R-type thermocouple. Direct photographs of soot particles have also been taken by transmission electron microscopy (TEM) through a thermophoretic sampling. Comparison of PAH and soot formation between the aliphatic fuels has shown the importance of fuel structure effect in diffusion flames.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.28A no.10
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• pp.814-820
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• 1991

TaSi$_2$ was formed by rapid thermal annealing(RTA) on BF$_2$ doped single crystalline silicon substrates. The formation and various properties of TaSi$_2$ have been investigated by using 4-point probe, HP414, XRD, and SEM. And the redistribution of boron with RTA has been observed by SIMS. Implanted boron was diffused out into the TaSi$_2$ for RTA temperature but did not significantly affect the formation temperature of TaSi$_2$. Also, the contact resistance for TaSi$_2$/p$^{+}$ region had a low value 22$\Omega$, at contact size of 0.9$\mu$m, and the native oxide formed on Si-substrates by BF$_2$ implantation retarded the formation of TaSi$_2$.

• Carbon letters
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• v.6 no.2
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• pp.96-100
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• 2005

Taguchi methodology has been applied to get an idea about the parameters related to the chemical vapour deposition technique, which influences the formation of semiconducting carbon thin film of a desired band gap. L9 orthogonal array was used for this purpose. The analysis based on Taguchi methodology suggests that amongst the parameters selected, the temperature of pyrolysis significantly controls the magnitude of band gap (46%). Sintering time has a small influence (30%) on the band gap formation and other factors have almost no influence on the band gap formation. Moreover this analysis suggests that lower temperature of pyrolysis (${\leq}$ $750^{\circ}C$) and lower time of sintering (${\leq}$ 1 h) should be preferred to get carbon thin film with the desired band gap of 1.2eV.

• Journal of Korean Society of Water and Wastewater
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• v.19 no.2
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• pp.181-192
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• 2005

This study evaluated the effect of factors influencing the initial biofilm formation in drinking water distribution pipe by running experiments using a $2^{4-1}$ fractional factorial experimental design with a replicate. Important variables used for assessing biofilm formation included BDOC(biodegradable dissolved organic carbon), viable heterotrophic bacteria present in drinking water, water temperature, and shear stress at two levels each. Based on the statistical analysis of biofilm levels measured as attached HPC(heterotrophic plate count) and community-level assay, the main factors that have significant effects on biofilm formation were found to be viable heterotrophic bacteria and BDOC. Water temperature only exhibited significant effect on the levels of attached HPC, while shear stress was not a significant factor under given conditions. Moreover, the statistical analysis revealed that interactions between the important variables were not statistically significant at a 0.05 significance level.