• Korean Journal of Food Science and Technology
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• v.52 no.1
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• pp.31-39
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• 2020

The effects of heat-moisture treatment (HMT) on the functional properties of high amylose rice starches (HARSes) purified from Korean rice varieties (A-type Goami and Singil and B-type Dodamssal and Goami2) were investigated. HMT was accomplished with moisture contents of 18 and 27% and heated at 100℃ for 16 h. While the amylose content, swelling power and solubility decreased after HMT, the water binding capacity and resistant starch (RS) content increased with increasing moisture content after HMT. The X-ray diffraction patterns of all HARSes did not change after HMT, but a decrease in the intensity of peak at 2θ=5° was observed in B-type HMT HARSes. While the starch granules aggregated after HMT, their shape and size remained unchanged. B-type HARSes exhibited higher gelatinization temperatures and lower pasting viscosities than A-type HARSes following HMT. The results, thus, suggest that while the crystalline intensity of B-type Dodamssal and Goami2 rice starches did not change after HMT, the RS content, water binding capacity, and pasting temperatures of all HARSes increased with increasing moisture content after HMT.

• Korean Chemical Engineering Research
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• v.44 no.4
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• pp.375-381
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• 2006

In this sturdy, spherical activated carbon(SPAC) contained $TiO_2$ was made by ion-exchanged treatment and heat treatment for applying fluidizing bed system. The ion-exchange resin was treated by $TiCl_3$ aqueous solution. The treated resin and raw resin were heat-treated under nitrogen condition to convert into Ti-SPAC. During the heat-treatment, burn-off weight amounts and the element were measured by means of TGA and TGA/MS, individually. The physicochemical properties of Ti-SPAC was characterized by means of XRD, SEM, EDS, BET, EPMA, ESR, intensity and titanium content. The Ti-SPAC had spherical shape with diameter size about $350{\mu}m{\sim}400{\mu}m$ and $617m^2/g$ specific surface area. Structure of $TiO_2$ in Ti-SPAC was anatase and rutile form. Also, $TiO_2$ on SPAC were found that the $TiO_2$ were uniformly distributed through EPMA analysis. Moreover, the Ti-SPAC showed indirect photocatalyst activity estimation through ESR analysis, characteristics of photocatalyst potentially. Over all results, Ti-SPAC was used in fluidizing bed UV/photocatalyst system to remove HA(Humic Acid). That results were HA removal efficiency was about 70％ and Ti-SPAC intensity was preserved during reaction. Ti-SPAC showed practical possibility as photocatalyst in fluidizing bed system.

• Korean Journal of Food Science and Technology
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• v.21 no.4
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• pp.480-485
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• 1989

Changes of color intensity and components during browning reaction of water extracts from white tail ginseng were investigated. Temperature dependence was described by the Arrhenius relationship with an activation energy of 16kcal/mole. Temperature sensitivities$(Q_{10}\;value)$ for water extracts of ginseng was 1.90 between $70^{\circ}C\;and\;80^{\circ}C$, 1.57 between $80^{\circ}C\;and\;90^{\circ}C$ and 1.46 between $90^{\circ}C\;and\;100^{\circ}C$. pH value of the solution treated at $90^{\circ}C\;and\;100^{\circ}C$ slightly increased with an increase in reaction time. Among ginseng saponins ginsenoside-Re was most unstable against heat-treatment, white diol group saponins were more stable against heat-treatment. Hydrogen donating activity (reducing activity for ${\alpha},\;{\alpha}'-diphenyl-{\beta}-picrylhydrazyl$) and 3,5-dinitrosalicylic acid(DNS) positive substances of browning reaction products increased in proportion to the length of browning reaction time and temperature, whereas folin positive substances decreased by heat-denaturation of ginseng protein at initial reaction time and then increased thereafter.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.10
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• pp.1178-1185
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• 2017

Two types of kimchi with a different total acidity (TA, 0.75% or 1.19%) were heated at $100^{\circ}C$ for up to 60 min to develop a gratin added with heated-kimchi. Their browning index and color intensity increased with increasing heating time, which was more apparent for the kimchi with the higher TA. This was attributed to the Maillard reaction facilitated at a higher heat intensity and by the smaller fermentation products. The same tendency was also observed for the antioxidant activities determined by the total reducing capacity, metal-chelating activity, and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity. In particular, heating kimchi at $100^{\circ}C$ only for 10 min increased the activities significantly. Therefore, the heated-kimchi was added to gratin at 20%. With the addition, the dietary fiber, ${\gamma}-aminobutyric$ acid (GABA) and ornithine contents in the gratin were increased appreciably (P<0.01). Nevertheless, there was little change in its salinity. The antioxidant activities of the gratin were significantly (P<0.001) higher than the control gratin without kimchi, with DPPH radical scavenging activity being 3.6 times higher. The results suggest that the functionality of kimchi could be effectually added to gratin even after heat treatment.

• Fire Science and Engineering
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• v.33 no.1
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• pp.69-75
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• 2019

In this study, the combustibility of five types of plastic plates, fiber reinforced plastic (FRP), polystyrene (PS), polycarbonate (PC), polypropylene (PP), and polyvinyl chloride (PVC), were tested using a cone calorimeter (ISO 5660). The PVC plate showed a $44.65kW/m^2$ lower peak heat release rate (HRR) and a $30.97kW/m^2$ lower maximum average rate of heat emission than the other four types of plastics, whereas the PS plate showed a $773.44kW/m^2$ higher peak HRR and $399.14kW/m^2$ higher maximum average rate of heat emission. The PC plate and PS plate showed the highest HRR by a maximum of 3.88 times in $CO_{mean}$ yields, while the PS pate and PP plate showed the highest HRR by a maximum 4.88 times in $CO_{2mean}$ yields. In addition, the smoke performance index (SPI) of the PS plate decreased by 74.81%~95.99%; the smoke growth index (SGI) increased to 76%~300%; the smoke intensity (SI) also increased to 917.73% ~ 9607.57%, and the danger of smoke increased. The PS plate was found to have the highest risk of life damage due to smoke on the thermal and smoke sides.

• Journal of the Korean Society of Safety
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• v.38 no.4
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• pp.39-46
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• 2023

Pine trees, which account for 23% of the forested area of the Republic of Korea, are highly vulnerable to fire in comparison to broad-leaved trees due to the presence of consistent water tube sections throughout the year and resin that is composed of approximately 20% oil. In addition, the pattern of forest fires is determined by weather, topographic conditions, and fluctuation in moisture content. Therefore, when fire breaks out in pine tree forests during the dry season (January to March), it is difficult to extinguish, and it quickly spreads. In this study, the combustion characteristics of pine needles, pine cones, and pine branches in the water tube sections of living pine trees were compared and analyzed in accordance with the moisture content as per the ISO 5660-1. The monthly moisture content was analyzed from January to March, and it was found to be the lowest in March, with 53.6% for pine needles, 51.9% for pine branches, and 10.9% for pine cones. In particular, pine cones were more vulnerable to fire as compared to pine needles and pine branches because their moisture content was more than five times lower than that of pine needles and branches. The ignition time, which affects the speed of flame propagation, was the most rapid in March, and the fastest ignition time was for pine cones, at 19 seconds, followed by 34 seconds for pine needles, and 256 seconds for pine branches. The pine branches were the last to be ignited due to the effect of density, according to the thickness and specific gravity of the specimen. The peak heat release rate, which is a measurable index of fire intensity, was analyzed for pine cones and found to be 184.28 kW/m² , while the mean effective heat of combustion was 19.79 MJ/kg, and the total heat release rate was 39.7 MJ/m² , and these values were higher than those of pine branches and pine needles. Thus, we determined that the flame propagation speed and fire intensity according to the moisture content can be used to evaluate the risk of fire to the water tube section of pine trees. It is suggested that because of the combustion characteristics of the pine cone in March, that is when the forest is most vulnerable to fires.

• Fire Science and Engineering
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• v.33 no.3
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• pp.9-20
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• 2019

This study was examined fire risk properties of wood specimen for the constructional interiors, especially focusing on the fire performance index (FPI) and the fire growth index (FGI) as heat hazard characteristics. Flame retardants were synthesized using boric acid, boronic acid and tetraethoxyorthosilicate. Heat release characteristics were measured by using a cone calorimeter (ISO 5660-1) and cypress was used. The external heat flux as fire intensity was maintained at 50 kW/㎡. The measured fire performance index (FPI) after burning was increased by 1.6 times for boric acid/silicone (BA/Si) sol, each 1.1 times for isobutylboronic acid/silicone (IBBA/Si) sol and phenylboronic acid/silicone (PBA/Si) sol compared with cypress. Fire risk by the fire performance index was increased BA/Si, IBBA/Si ≈ PBA/Si order. The fire growth index was decreased 94% for the BA/Si and 8% for the IBBA/Si sol, and was increased by 17% for the PBA/Si sol. Fire risk by the fire growth index was increased BA/Si, IBBA/Si, PBA/Si order. Overall fire risk was higher in the order of BA/Si < IBBA/Si < PBA/Si.

• Korean Journal of Materials Research
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• v.13 no.3
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• pp.174-179
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• 2003

Thin copper films were grown by electrodeposition on copper seed layers which were grown by sputtering of an ultra-pure copper target on tantalum nitride-coated silicon wafers and subsequently, cleaned in ECR plasma. The copper films were then subjected to ⅰ) vacuum annealing, ⅱ) rapid thermal annealing (RTA) and ⅲ) rapid thermal nitriding (RTN) at various temperatures over different periods of time. XRD, SEM, AFM and resistivity measurements were done to ascertain the optimum heat treatment condition for obtaining film with minimum resistivity, predominantly (111)-oriented and smoother surface morphology. The as-deposited film has a resistivity of ∼6.3 $\mu$$\Omega$-cm and a relatively small intensity ratio of (111) and (200) peaks. With heat treatment, the resistivity decreases and the (111) peak becomes dominant, along with improved smoothness of the copper film. The optimum condition (with a resistivity of 1.98 $\mu$$\Omega$-cm) is suggested as the rapid thermal nitriding at 400oC for 120 sec.

• Journal of The Korean Astronomical Society
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• v.37 no.5
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• pp.543-546
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• 2004

The inverse Compton scattering of the cosmic microwave background (CMB) radiation with electrons in the intracluster medium which has a temperature gradient, was examined by the third-order perturbation theory of the Compton scattering. A new type of the spectrum distortion of the CMB was found and named as gradient T Sunyaev-Zel'dovich effect (gradT SZE). The spectrum has an universal shape. There is a zero distortion point, the cross over frequency, at 326GHz. When the hotter region locates closer to an observer, the intensity becomes brighter than the CMB in the frequency region lower than the cross over frequency and fainter than the CMB in the frequency region higher than the cross over frequency. When the cooler region locates closer to an observer, the distorted part of the spectrum has an opposite sign to the above case. The amplitude of the spectrum distortion does not de-pend on the electron density and depends on the heat conductivity and the total temperature variation along a line of sight. Therefore, the gradT SZE provides an unique opportunity to measure thermally nonequilibrium electron momentum distribution function in the ICM and combined with the X-ray measurements of the electron temperature distribution provides an opportunity of direct measurement of the heat conductivity in the ICM.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.36 no.2
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• pp.139-146
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• 2000

Cavitation can occur in pipes when liquid is moving at high velocity, especially at pittings where the smooth bore of the pipe is interrupted. The effect is usually to produce pitting on the downstream side of the turbulence. However, stress corrosion cracking behavior under cavitation erosion-corrosion was neatly unknown. In this study, therefore, some were investigated of stress corrosion cracking behavior, others were stress corrosion cracking behavior under cavitation erosion-corrosion of water injection. And datas obtained as the results of experiment were compared between the two. Mainresult obtained are as follows: 1) Stress corrosion cracking growth rate of heat affected zone under cavitation erosion-corrosion becomes most rapid, and stress intensity factor $K_1$becomes most high. 2) Stress corrosion cracking growth mechanism by cavitation erosion-corrosion is judgement on the strength of the film rupture model and the tunnel model. 3) The range of potential as passivation of heat affected zone is less noble than that of base metal, and that value is smaller. 4) Corrosion potential under cavitation erosion-corrosion in loaded stress is less noble than that of stress corrosion, and corrosion current density is higher.