• Journal of The Korean Association For Science Education
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• v.25 no.5
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• pp.555-562
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• 2005

This study investigated the effects of cooperative learning environments in conceptual change instruction upon students' conception, achievement, learning motivation, attitude toward science instruction, and perception of involvement. Two classes of 8th graders at a co-ed middle school were assigned to the treatment and the comparison groups. They were taught about density, boiling point, freezing point, and solubility for 11 class hours. The treatment group's learning environment involved cooperative conceptual change instructions while the comparison group's environment incorporated individual conceptual change instructions. Mann-Whitney test results revealed that the scores of the conception and achievement test for the treatment group were significantly higher than those for the comparison group. The perceptions of involvement for the treatment group were more positive than those for the comparison group. The scores of the learning motivation test for the treatment group were found to be significantly higher than those for the comparison group based on a two-way ANCOVA analysis. However, attitudes toward science instruction were not found to be significantly different between the two groups.

• Korean journal of food and cookery science
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• v.11 no.1
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• pp.20-25
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• 1995

The effects of cooking on the dietary fiber content in rice, brown rice, yellow soybean and black soybean were investigated. The dietary fiber contents were analyzed by Prosky's method(AOAC method) after boiling, microwave heating and autoclaving of the sample. It was showed that the different cooking methods resulted in different effects on the insoluble dietary fiber contents. Except yellow soybean, cooking time had little effect on insoluble dietary fiber contets in the other samples. The contents of soluble dietary fiber were generally increased by cooking. Increased cooking time reduced the content of soluble dietary fiber in brown rice but increased in rice. However, no significant differences caused by cooking time were observed for soluble dietary fiber in black soybean. The effects of cooking method on the total dietary fiber contents were similar to those of insoluble dietary fiber. The reasons for this might be that the main fraction of total dietary fiber was insoluble forms and the content of total dietary fiber was calculated as the sum of insoluble and soluble dietary fiber content.

• Journal of Energy Engineering
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• v.2 no.2
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• pp.179-186
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• 1993

Heat pipes. applied to a flat plate solar collector, have a long and slender configuration with relatively low heat flux in the evaporator section. Such a heat pipe has a tendency to build-up a liquid pool at the lower part of the evaporator section. and at this pool occurs such complicated phenomena of evaporation and fluid dynamics as superheat, sudden generation of bubble, its likely explosive growth process and flooding, etc. In the present study. we tried to solve these problems by means of adjusting two principal design parameters, the liquid inventory and the installation region of the wick, using 4 heat pipes and 3 thermospheres. The corresponding results can be summarized as follows$\^$1)/. The effective thermal conductances of the heat pipe was greatly improved by eliminating the wick in the adiabatic and condenser sections$\^$2)/. The liquid inventory should be increased by about 40% larger than what is saturated the wick$\^$3)/. In the evaporator section the wick has a favorable effect to reduce both unstable operation by intermittent occurrence of nucleate boiling and response time at the initial start-up process.

• Proceedings of the KSRS Conference
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• 2008.10a
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• pp.3-5
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• 2008

An increase in oil and gas plants caused by development of process industry have brought into the increase in use of flammable and toxic materials in the complex process under high temperature and pressure. There is always possibility of fire and explosion of dangerous chemicals, which exist as raw materials, intermediates, and finished goods whether used or stored in the industrial plants. Since there is the need of efforts on disaster damage reduction or mitigation process, we have been conducting a research to relate explosion model on the background of real 3D terrain model. By predicting the extent of damage caused by recent disasters, we will be able to improve efficiency of recovery and, sure, to take preventive measure and emergency counterplan in response to unprepared disaster. For disaster damage prediction, it is general to conduct quantitative risk assessment, using engineering model for environmental description of the target area. There are different engineering models, according to type of disaster, to be used for industry disaster such as UVCE (Unconfined Vapour Cloud Explosion), BLEVE (Boiling Liquid Evaporation Vapour Explosion), Fireball and so on, among them, we estimate explosion damage through UVCE model which is used in the event of explosion of high frequency and severe damage. When flammable gas in a tank is released to the air, firing it brings about explosion, then we can assess the effect of explosion. As 3D terrain information data is utilized to predict and estimate the extent of damage for each human and material. 3D terrain data with synthetic environment (SEDRIS) gives us more accurate damage prediction for industrial disaster and this research will show appropriate prediction results.

• Journal of the Korean Institute of Gas
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• v.18 no.2
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• pp.16-20
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• 2014

In this paper, the performance of pressure-resistance is validated by experiment on LPG re-fillable cylinder which has increased demands for spreading of camp culture. Propane has increased suppliable requirements as fuel because of easily vaporizing effect of low boiling point. However, propane can be occurring safety problems inevitably by high vapor pressure. So, the priority is that safe cylinder should furnish in order to be circulated as safe fuel. LPG re-fillable cylinder for high pressure is tried to furnish internationally, that is restricted by safe issues. For these reasons, the pressurization and rupture are performed by using pressurizing device that is operated by hydraulic system. Also, this paper will offer rupturable characteristics comparing with vapor pressure of propane. This paper is expected as basis research for developing re-fillable cylinder and using standard for supplying them.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.6
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• pp.898-903
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• 2015

Noroviruses (NoV) are known to cause acute epidemic gastroenteritis worldwide. Outbreak strains are predominantly genogroup I (GI) and genogroup II (GII) in oysters Crassostrea gigas. We investigated the changes in concentration of male specific coliphage (MSC) and NoV under heat treatment of the naturally contaminated oyster, Crassostrea gigas. After heat treatment for 5 min in $85^{\circ}C$, no viable MSC was detected. The concentrations of GI and GII NoV decreased by 1.65 log and 2.25 log, respectively, following heat treatment for 5 min at $100^{\circ}C$. Moreover, both GI and GII NoV were completely deactivated by heat treatment for 10 min at $100^{\circ}C$. Therefore, in order to reduce the risk of norovirus infection from contaminated oysters, immersion in boiling water for at least 10 min is recommended.

• The Korean Journal of Food And Nutrition
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• v.26 no.3
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• pp.375-382
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• 2013

The present study is designed to explore an anti-tumor activity on crude extracts of Oplopanax elatus. Water extractions of Oplopanax elatus were performed at $100^{\circ}C$(OeE-100). OeE-100 doses up to $62.5{\mu}g/m{\ell}$ had no cytotoxicity on the tumor cell lines in vitro. In experimental lung metastasis of colon26-M3.1 carcinoma or B16-BL6 melanoma, the prophylactic intravenous ($4{\sim}100{\mu}g/mouse$) or oral (2 mg/mouse) administration of OeE-100 significantly inhibited tumor metastasis as compared with tumor controls. Peritoneal macrophages stimulated with OeE-100 produced various cytokines such as TNF-${\alpha}$, IL-6 and IL-12. In an analysis of NK-cell activities, i.v. administration of OeE-100 ($10{\sim}100{\mu}g/mouse$) significantly augmented the cytotoxicity to YAC-1 tumor cells. Vaccination of mice with boiling-treated tumor cells (BT-vaccine) in combination with OeE-100 ($100{\mu}g/mouse$) showed higher inhibitions in tumor metastasis when compared with the mice of BT-vaccine treatment. In addition, the splenocytes from OeE-100 admixed BT-vaccine immunized mice secreted a higher concentration of Th1 type cytokine such as IFN-${\gamma}$. These results suggested that the OeE-100 stimulated immune system and was a good candidate adjuvant of anti-tumor immune responses.

• Korean journal of food and cookery science
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• v.26 no.2
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• pp.171-179
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• 2010

The objectives of this study were to investigate the antioxidative activity of crackers made with a guava(Psidium guajava Linn.) leaf extract harvested in Korea. Guava leaf extraction using boiling water showed significantly higher antioxidative activities than extracting using 70% ethanol based on the higher total phenolic contents, FRAP, and ABTS assays(p<0.05). The crackers containing 1% guava leaf extract, and 0.075% BHT were stored at $63^{\circ}C$ for 7 days for the Schaal oven test, and the oxidative stability(AV, POV), antioxidative activity(DPPH, FRAP, ABTS assay), and sensory evaluation were compared. The crackers containing 1% guava leaf extract were found to have a higher oxidative stability than the control due to a lower acid value and peroxide value after 7 days of storage. The antioxidative activities of the crackers containing 1% guava leaf extract was the highest after 7 days as determined in the DPPH and ABTS assay, and was lower than crackers containing 0.075% BHT after 4 days as assessed by the FRAP assay. In the sensory evaluation, the crackers containing the 1% guava leaf extract had the highest scores in terms of taste, texture, and overall palatability than others at increasing storage time. As a result, the addition of 1% guava leaf extract harvested in Korea increased the antioxidative effect as well as the sensory acceptability of crackers.

• Korean Journal of Food Science and Technology
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• v.26 no.2
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• pp.127-132
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• 1994

Removal of viscous materials, mainly alginate, from sea tangle extracts by $CaCl_2$ precipitation or ultrafiltration was investigated. The sea tangle extracts were prepared by enzymatic hydrolysis of polysaccharides followed by 2 hours of boiling in 1.5% NaCl or 2.0% sucrose solution. The $CaCl_2$ precipitation resulted in higher amount of total solid, amino-nitrogen and mannitol than those values of ultrafiltration, but protein extracted was less in the former. Both methods caused a significant decrease in the viscosity and turbidity of the extracts. The composition of four nucleotides showed that UMP and IMP were not detected in $CaCl_2$ precipitated extracts, while ultrafiltered extracts showed a fairly even distribution of them. Removal of viscous material, particularly ultrafiltration increased the glutamic acid in amino acid composition and reduced serine, histidine, lysine, glycine, phenylalanine and leucine.

• Korean Journal of Food Science and Technology
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• v.19 no.6
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• pp.480-485
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• 1987

Quick cooking rice was produced by cooking raw, white long grain rice with three different methods which were atmospheric cooking in electric cooker, autoclaving and precooking followed by autoclaving. The drying rate curve showed that cooking methods affected little the drying pattern of the cooked rice except that precooking treatment before autoclaving retarded dehydration. The quick cooking rice prepared by precooking and autoclaving method among three cooking methods showed the fastest rehydration rate and took 7.5 minutes in reaching equilibrium moisture content by soaking in boiling water. And it had less hard and more cohesive texture than the milled rice cooked by conventional method and the quick cooking rice prepared by electric cooking when reconstituted. The microstructure of quick cooking rice was investigated among cooking methods.