• Applied Biological Chemistry
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• v.39 no.5
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• pp.338-342
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• 1996

Fruit of Lycium chinense Miller was known to Korean as traditional medicine that has effective components for strengtherning function of human body, especially liver. To study characteristics of the wine and Yakju made by fruit Lycium chinense Miller, general components such as organic acid, methanol, ester, fusel oil and $SO_2$ were analyzed after storing them for 10 and 20 days at $20^{\circ}C\;and\;30^{\circ}C$, respectively. Organic acid contents of the wine were mainly lactic, malic, tartaric and acetic acid. Ester and fusel oil contents of the wine were $4.0{\sim}5.0\;mg%$ and $12{\sim}30\;mg%$, respectively, and the values were smaller than those of the Yakju. Methanol content of the wine was $25{\sim}27\;mg%$. Storage temperature in terms of the quality of the wine and Yakju was better in $20^{\circ}C\;than\;30^{\circ}C$. Treatment of the wine and Yakju either by adding 100 ppm of $SO_2$ or heating at $60^{\circ}C$ for 30 min was better in quality than control for storage.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.11
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• pp.878-885
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• 2012

In this study we aims to examine the co-doping effects of 1/3 mol% $Mn_3O_4+Co_3O_4$ (1:1) on the reaction, microstructure, and electrical properties such as the bulk defects and grain boundary properties of $ZnO-Bi_2O_3-Sb_2O_3$ (ZBS; Sb/Bi=0.5, 1.0, and 2.0) varistors. The sintering and electrical properties of Mn,Co-doped ZBS, ZBS(MCo) varistors were controlled by Sb/Bi ratio. Pyrochlore ($Zn_2Bi_3Sb_3O_{14}$) was decomposed and promoted densification at lower temperature on heating in Sb/Bi=1.0 by Mn rather than Co. Pyrochlore on cooling was reproduced in all systems however, spinel (${\alpha}$- or ${\beta}$-polymorph) did not formed in Sb/Bi=0.5. More homogeneous microstructure was obtained in $Sb/Bi{\geq}1.0$ In ZBS(MCo), the varistor characteristics were improved drastically (non-linear coefficient, ${\alpha}$=30~49), and seemed to form $Zn_i^{..}$(0.17 eV) and $V_o^{\bullet}$(0.33 eV) as dominant defects. From impedance and modulus spectroscopy (IS & MS), the grain boundaries have divided into two types, i.e. the one is tentatively assign to $ZnO/Bi_2O_3(Mn,Co)/ZnO$ (0.47 eV) and the other ZnO/ZnO (0.80~0.89 eV) homojunctions.

• Journal of Soil and Groundwater Environment
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• v.22 no.6
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• pp.112-119
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• 2017

In this study, the availability of cow manure as raw material for solid fuel production was investigated. Since the water content of the cow manure was too high, it was dewatered using a laboratory hydraulic compressure ($11.3kg/cm^2$). The moisture content of the cow manure decreased from 82.01% to 73.36 wt.%. The dewatered cow manure was homogenized by the experimental apparatus and then put into the rotating cylindrical apparatus. From the consecutive processes, the cow ball-shaped pellet which size ranged from 3.0 to 25.0 mm was produced. The major factor for making palletized fuel from cow manure was the moisture content. Based on the experimental data, the moisture content of cow manure for pelletizing cow manure was identified as 65~75 wt.%. When the moisture content of the cow manure was lower than 30 wt.%, the diameter of the pellets maded from cow manure was smaller than 3 mm. On the other hand, when the water content of the cow manure was higher than 75 wt/%, the diameter of the processed pellets tended to be larger than 25 mm. The characteristics of the processed cow manure pellets was analyzed to be in accordance with the livestock solid fuel quality standard. The pyrolysis characteristic of the pellet was analyzed by raising the heating temperature of the experimental equipment from 200 to $900^{\circ}C$. The mass change between of 20 and $130^{\circ}C$ corresponds to the amount of moisture contained in the cow manure. The amount of moisture was about 15% of the total weight of cow manure samples. The cow manure pellet was thermally stable up to $280^{\circ}C$. It can be interpreted that combustion of cow manure pellet does not occur until the surface temperature reaches $280^{\circ}C$. The mass change of pellet between of 280 and $450^{\circ}C$ was considered to be due to the vaporization of volatile organic compounds (VOCs) present in the cow manure pellet. The maximum production of VOCs was showed near $330^{\circ}C$.

• Journal of agriculture & life science
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• v.45 no.2
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• pp.115-123
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• 2011

Seasoning gochujang sauces were prepared with 0, 10, 20 and 30% concentrated heating chopped garlic (garlic base) and analyzed. These seasoning gochujang storage for 40 days at $37{\pm}1^{\circ}C$ and examined for changes in their physicochemical properties. Hunter color L and b-value of seasoning gochujang were decreased slowly till 20 days of storage then increased afterward. The highest pH of the seasoning gochujang was pH 5.22 in the 30% garlic base added group. The titratable acidity increase significantly till 40 days of storage. As the adding ratio of garlic base increased, reducing sugar content was decreased. The amino-nitrogen content was continually decreased during aging up to 40 days. ABTs radical scavenging activity was increased as garlic base addition level was increased. The activity was decreased with passing by storage period, and below 50% at 40 days storage.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.6
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• pp.1035-1039
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• 2010

For 65 national forest areas in 1993 to 2008, the ambient sulfur dioxide ($SO_2$) concentrations were measured monthly using passive samplers and compared to the those of urban areas in order to investigate the characteristics of temporal and spatial distribution. In the forest areas, annual average concentration of sulfur dioxide gradually decreased from the beginning year of monitoring to 1997 and then had no significant change, such as the annual trend in urban areas monitored by Ministry of Environment. For the monitoring term, average concentration of sulfur dioxide in the forest areas was 5.6ppb, which was lower than the 10.1ppb in the urban areas and the EC ecological standard level (7.6 ppb). Seasonally, both in forest areas and urban areas the monthly average concentrations were much higher in winter and spring due to much more heating fuel consumption, and lowest in summer. Regional comparison to other regions of Gyeongbuk and Gyeonggi province showed that the concentration of sulfur dioxide was the highest during year. A significant positive correlation between sulfur oxides' emissions and sulfur dioxide concentration by province was observed, reflecting that the size and proximity of sources of atmospheric sulfur oxides could be important factors in determination.

• Korean Chemical Engineering Research
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• v.59 no.4
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• pp.611-625
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• 2021

Mg crowns were manufactured using domestic dolomite (Ca·Mg(CO₃)₂) (20~30 mm). In order to manufacture the calcined dolomite (CaO·MgO), (a) electric furnace (950 ℃, 480 min) and (b) microwave furnace (950 ℃, 60 min) processes were used. As a result of XRD analysis, it was analyzed as (a) CaO 56.9 wt%, MgO 43.1 wt% by electric furnace process and (b) CaO 55 wt%, MgO 45 wt% by microwave furnace process. Even when the decarbonation reaction time of dolomite was shortened by 1/8 in microwave furnace process compare with electric furnace process, the calcined dolomite could be produced. The hydration reaction (ASTM C 110) is a standard for the hydration reactivity of calcined dolomite, and the calcined dolomite produced by electric furnace process showed a high hydration reactivity (max temp 79.8 ℃/1.5 minutes). Such hydration reactivity was occurred by only CaO hydration reaction and that was confirmed by XRD analysis. The calcined dolomite produced by microwave furnace process showed low hydration reactivity (max temp 81.7 ℃/19.5 minutes). Such low hydration reactivity was occurred by CaO and MgO hydration reaction due to the hydration reaction of CaO thereafter occurring of the hydration reaction of MgO, and that was confirmed by XRD analysis. The prepared Mg crown were 58.8 g and 74.6 g by electric furnace and microwave furnace processes, respectively, under the reaction conditions of 1,230 ℃, 60 min, 5 × 10^-2 torr by silicothermic reduction.

• Resources Recycling
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• v.30 no.6
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• pp.68-75
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• 2021

This study aims to investigate the manufacturing process of calcium chloride-based special cement, i.e., CCA (calcium chloro aluminate, C₁₁A₇·CaCl₂), which uses limestone, by using one type of random industrial by-product, domestic coal ash, cement kiln dust. The manufacturing process of was examined in detail, and the results suggested that the amount of CCA synthesized increased with an increase in the firing temperature. The manufacturing process of CCA was investigated at 1200℃, which was determined as the optimum firing temperature. The results showed that in general, the amount of CCA synthesized tended to increase with an increase in the firing time; however, the clinker melted when the firing time was more than 30 min, thereby suggesting that a firing time of less than 20 min would be suitable for the clinkering process. The optimal firing conditions for manufacturing CCA were obtained as follows: heating rate of 10 ℃/min, firing temperature of 1200 ℃, and holding time of 20 min. The results also suggest that manufacturing CCA will be easier when high chlorine-containing cement kiln dust is used.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.4
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• pp.207-213
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• 2019

This study aimed to provide basic data for the development of education programs on food hygiene attitude and personal hygiene management of high school students according to gender. From July 16 to October 15, 2015, questionnaires were distributed to 30 students per grade at 16 high schools in Chungcheongnam-do, and a total of 1,214 questionnaires(excluding uncollected and insufficient questionnaires) were processed using SPSS(ver 18.0). According to the study, female students more checked the expiration date for food(3.78, 3.57), ate stored food without heating(2.83, 3.02) and stored it according to the characteristics(3.92, 3.72) than male students. On the other hand, male students answered they looked at food packaging more closely(3.34, 3.22), and always used personal plates when they ate(3.43, 3.32), than female students. Female students were always better at hand washing after went to toilet(4.25, 3.94), used individual cups when using water purifiers(3.45, 3.32), kept nails cleaner(3.61, 3.49), and went around(2.14, 2.53) and went to toilet during meals than male students(2.22, 2.57). Boys answered they were better at hand washing before meals(3.64, 3.50), with right way(3.58, 3.46), and covering with a tissue, handkerchief or sleeve when they coughed(3.55, 3.37) than girls. In this study, high school students showed significant differences between gender in food hygiene attitude and personal hygiene management, with different areas requiring improvement. Therefore, this study suggests the need for education on food hygiene attitude and personal hygiene management differentiated according to gender.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.2
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• pp.173-179
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• 2019

This study aimed to provide basic data for the development of education programs on food hygiene attitude and personal hygiene management of high school students by type of school. From July 16 to October 15, 2015, questionnaires were distributed to 30 students per grade at 16 high schools in Chungcheongnam-do, and a total of 1214 questionnaires (excluding unrecurring and insufficient questionnaires) were processed using SPSS (ver 18.0). As a result, academic high school students answered more checking food's shelf life when they bought it in the store(3.79, 3.60), not eating the cooked and heated food after keeping without heating(2.85, 2.98), and storing food in the refrigerator in accordance with its characteristics(3.90, 3.76) than specialized high school students. Academic high school students were found to be more careful than specialized high school students, to wash hands before meals(3.66, 3.52), after went to toilet(4.30, 3.95), in the right way(3.63 and 3.45), and to go around less during meal time(2.19, 2.43) and to go to the toilet less often during meal time(2.28, 2.47). In this study, academic and specialized high school students showed significant differences in food hygiene attitude and personal hygiene management, and academic high school students had significantly better food hygiene attitude and personal hygiene control than specialized high school students. but still need to be improved. Therefore, it is suggested that education on food hygiene attitude and personal hygiene management should be strengthened according to the type of school.

• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.4
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• pp.311-318
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• 2018

When reinforced concrete structures are exposed to fire, their mechanical properties such as compressive strength, elasticity coefficient and rebar yield strength, are degraded. Therefore, the structure's damage assessment is essential in determining whether to dismantle or augment the structure after a fire. In this study, the confinement effect of lateral reinforcement of RC column according to the numbers of fire exposure face and stirrup was verified by fire resistant test with the heating temperatures of $400^{\circ}C$, $600^{\circ}C$ and $800^{\circ}C$. The test results showed that the peak stress decreases and peak strain increases as the temperature is getting higher, also transverse ties are helpful in improving the compressive resistance of concrete subjected to high temperature. Based on the results of this study, the residual stress of confined concrete under thermal damage is higher at the condition of more lateral reinforcement ratio and less fire exposure faces. The decreasing ratio of elastic modulus of more confined and less exposure faces from the relationship of load and displacement was also smaller than that of opposite conditions.