• Journal of Food Hygiene and Safety
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• v.38 no.4
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• pp.236-245
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• 2023

In this study, the quality safety limit period of seven types of bakery bread was analyzed, and their use-by date was calculated. For evaluating product quality, storage conditions were set as 5, 15, 25, and 35℃ for 50 days, and moisture, microorganisms, sensory characteristics, and dominant bacteria were examined. The quality and safety standards followed the Korea Food Code and Korean industrial standards (KS). The results showed that all products stored at 5℃ satisfied the standard for bacterial count for day 50, but the sensory quality was below the standard level. Samples stored at 15℃ showed high variability from 3-39 days. At 25℃, a quality safety limit period of 2-20 days was set, and one sample was found to have the same shelf life. Bread stored at 35 ℃ had the shortest quality safety limit period. Considering a safety factor of 0.87, a use-by date period of 1.7-13.1 days was calculated. Therefore, setting the use-by date according to the product type is necessary, even for the same product category. Among the bread products sold in bakeries, those managed as room temperature products (1-35℃) can be distributed and stored in a temperature range of up to 35℃. Overall, this study demonstrates the importance of setting a quality retention period based on the product characteristics and carefully considering the safety factor.

• Journal of the Korean Society of Food Culture
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• v.28 no.1
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• pp.70-77
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• 2013

This study was conducted to evaluate the effects of chestnut powder on antioxidant activity and quality characteristics of cookies. Cookies were prepared using different amounts of chestnut powder (0, 5, 10, 15 and 20% to the flour quantity). The antioxidant activity was estimated by measuring DPPH free radical scavenging activity and the total phenolic content in chestnut powder and cookies. In addition, the quality characteristics of the chestnut cookies were estimated based on: the bulk density and pH of the dough, spread factor, loss rate, leavening rate, color, texture profile analysis, and sensory evaluations. The spread ratio, a values, total polyphenol contents, and DPPH free radical scavenging activity of cookies significantly increased with increasing chestnut powder (p<0.001), while the leavening rate, L values, b values and hardness of the cookies significantly decreased with increasing chestnut powder (p<0.05). The sensory evaluation scores for the 15% chestnut powder cookie groups ranked significantly higher (p<0.05) than the other groups in overall preference, appearance, taste, color, chestnut taste, oily flavor, and aftertaste. Taken together, the results of this study suggest that chestnut powder is a good ingredient for increasing the consumer acceptability and functionality of cookies.

• Nutrition Research and Practice
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• v.12 no.4
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• pp.342-347
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• 2018

BACKGROUND/OBJECTIVES: School meals are not just meals consumed at school, they are part of the culture, education, and life experience at school. Nevertheless, few studies have revealed the influence of school meals on students' school lives. The purpose of this study was to investigate the effect of satisfaction with the school meal program on students' school happiness. SUBJECTS/METHODS: A survey conducted in December 2015 asked 2,336 students (1,062 elementary school students, 880 middle school students, and 394 high school students) about their satisfaction with the school meal program and their school happiness. Multiple regression analyses were used to examine the relation between the students' school meal satisfaction and their happiness level. RESULTS: The average level of satisfaction with school meals of elementary school students was 4.1 out of 5 points, comparatively higher than that of middle and high school students, with a significant difference between school levels (P < 0.001). In addition, school happiness, as well as overall happiness, of elementary school students was higher than that of middle and high school students (P < 0.001). The school meal operation factor (0.232, P < 0.001) had the most influence on students' school happiness, followed by the school meal environment factor (0.219, P < 0.001) and school meal quality factor (0.136, P < 0.001). Overall satisfaction (0.097, P = 0.001) and school meal hygiene factor (0.095, P = 0.001) also had significant influences on students' school happiness. CONCLUSIONS: Students' satisfaction with the school meal program was related to their school happiness. Therefore, plans to enhance students' satisfaction with a school meal program needs to be implemented, with emphasis on placing a priority on school meal operation and school environment factors, in order to improve students' level of happiness.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.9
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• pp.838-842
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• 2006

0.03Pb$(Sb_{0.5}Nb_{0.5})O_{3}-0.03Pb(Mn{1/3}Nb{2/3)O_{3}-(0.94-x)PbTiO_{3}-xPbZrO_{3}$ ceramics doped with $CeO_{2}$ were synthesized by conventional bulk ceramic processing technique. Phases analysis, microstructures and piezoelectric properties were investigated as a function of $CeO_{2}$ content (0.03, 0.05, 0.1 0.3, 0.5 and 0.7 wt%). Microstructures and phases information were characterized using a scanning electron microscope (SEM) and an X-ray diffractometer (XRD). Mechanical quality factor ($Q_{m}$) and coupling factor(kp) were obtained from the resonance measurement method. Both $Q_{m}$ and $k_{p}$ were shown to reach to the maximum at 0.1 wt% $CeO_{2}$. In order to evaluate the stability of resonance frequency and effective electromechanical coupling factor ($K_{eff}$) as a function of $CeO_{2}$, the variation of resonance and anti-resonance frequency were also measured using a high voltage frequency response analyzer under various alternating electric fields from 10 V/mm to 80 V/mm. It was shown that the stability of resonance frequency and effective electromechanical coupling factor were increased with increasing the $CeO_{2}$ contents.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.6
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• pp.478-484
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• 2000

The structural changes and the microwave dielectric properties of $Ba_{1-x}$/A$_{x}$/(Mg$_{1}$3//Nb$_{2}$3/)O$_3$(A=Sr, Ca=x0, 0.2, 0.4, 0.6, 0.8, 1.0) were investigated. The densities of samples are gradually decreased with increasing x(BMN=6.1, SMN=5.22 and CMN=4.26 g/m$^3$)The crystal structure of BMN was untilting of oxygen octahedral. The structural changes of BSMN showed the antiphase tilting at x>0.4, and those of BCMN showed the antiphase tilting at 0.20.8. The variation of dielectric constant with Sr was small(BMN=32, SMN=30) However the variation with Ca was large the highest value was 42 at Ca=0.2(CMN=25) The maximum quality factor was 68,000 GHz at Sr=0.2 and the minimum quality factor was 3,000 GHz at Ca=0.2 (BMN=35,000, SMN=20,000 and CMN=23,000 GHz) The temperature coefficients of resonant frequency of BSMN were about 2 times larger than those of BCMN in all composition.ion.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.226-229
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• 2005

In this study, a step-down piezoelectric transformer was fabricated to utilize as an adapter for charging batteries of mobile electronic appliances. The ceramic part of the transformer is $Pb[(Mn_{1/3}Sb_{2/3})_{0.05}Zr_{0.475}Ti_{0.475}]O_3$ with mechanical quality factor of 1600, electromechanical coupling coefficient 59 %, and piezoelectric constant d33 1300, which can be utilized as a piezoelectric transformer. A simply fabricated disk-typed test pattern of diameter 28 mm and thickness 2 mm was used to characterize resonant frequency, Qm, kp according to the different input/output electrode area. efficiency and power as a function of load resistance was also investigated. The sample APT showed some spurious mode and BPT showed better frequency property. Taking all properties which are admittance, effective electromechanical coupling coefficient and mechanical quality factor most suitable for piezoelectric transformer is BPT which has 12 mm diameter electrode and the condition of 15 Vrms, 30 $\Omega$ made the maximum efficiency of 93.7 % and maximum power is 6W with 50 Vrms.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.11
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• pp.1007-1013
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• 2005

In this study, a step-down piezoelectric transformer was fabricated to utilize as an adapter for charging batteries of mobile electronic appliances. The ceramic part of the transformer is $Pb[(Mn_{1/3}Sb_{2/3})_{_0.05}Zr_{0.475}Ti_{0.475}]O_3$ with mechanical quality factor of 1600, electromechanical coupling coefficient $59\%$, and piezoelectric constant $d_{33}$ 1300, which can be utilized as a piezoelectric transformer. A simply fabricated disk-typed test pattern of diameter 28 mm and thickness 2 mm was used to characterize output voltage, step-down ratio as a function of electrode area with the input remained constant, and power, efficiency as a function of input voltage, and temperature-dependent electric characteristics were evaluated. The sample APT1 showed the best properties. The highest admittance, effective electromechanical coupling coefficient and an appropriate mechanical quality factor were obtained at the sample with the input/output area ratio of 1:1.5 at the common electrode, and the condition of 20 $V_{rms}$, $50\;\Omega$ made the maximum efficiency of $95\%$. The temperature was increased by 14.7'E as the input voltage was increased for $50\;V_{rms},\;50\;\Omega$.

• Journal of Korean Society for Atmospheric Environment
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• v.2 no.1
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• pp.81-90
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• 1986

Hanna - Gifford Model and Air Quality Display Model(AQDM) were validated in the simulation of $SO_2$ and TSP concentrations of Seoul City. The observed data which were measured at 16 sites of air monitoring system conducted by Seoul metropolitan city in 1984 were compared with the simulated data and the results were obtained as follows; 1. Several different meteorological data were examined: The particularities of meteorological data was not an influencing factor in the validity of simulation. The simulations of $SO_2$ by Hanna - Gifford model and by AQDM showed close correlation coefficients between the observed data and the simulated data (r = 0.71 - 0.78). 2. The simulation models showed different validities with the seasonal variation: The correlation coefficients (r) between the observed and the simulated by Hanna - Gifford Model for $SO_2$ and TSP were 0.86 and 0.80 in Spring, 0.63 and 0.66 in Summer, 0.76 in Autumn and 0.81 and 0.93 in Winter respectively. Those by AQDM were 0.73 and 0.68 in Spring, 0.56 and 0.79 in Summer, 0.77 and 0.76 in Autumn and 0.64 and 0.68 in Winter respectively. 3. The simulated data by two models had a close relationships: The correlation coefficients between them were 0.96 for $SO_2$, and 0.93 for TSP. With the above results, the application of models was discussed; Hanna - Gifford model was less valid in the simulation for the air quality of $SO_2$ and TSP in Seoul in Summer and AQDM also was not valid for $SO_2$ in Summer and in Winter and for TSP in Spring.

• The Journal of Korean Obstetrics and Gynecology
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• v.28 no.1
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• pp.85-91
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• 2015

Objectives: Postmenopausal symptoms are subject to many factors. Recently, obesity has been suggested as a factor of hot flush. So this study aims to report the relationship between body composition and Menopause Rating Scale (MRS), The Menopause-specific Quality of Life Questionnaire (MENQOL) of postmenopausal women. Methods: We studied 42 climacteric women who had visited Kyung Hee University Hospital at Gangdong from April 2011 to July 2014. 42 women had filled out MRS, MENQOL, and they had taken body composition tests. Pearson correlation tests were conducted. (Correlation was statistically significant at the 0.05 level) Results: Correlation between psychological subscale of MENQOL and Waist-Hip Ratio (WHR) was statistically significant (pearson correlation coefficient=0.385; p-value=0.012). But other subscales of MRS and MENQOL were not statistically related with body composition. Conclusions: WHR could be an important factor of psychological health of menopausal women. So, abdominal fat reduction must be considered when curing menopausal symptoms. In connection with climacteric depression, well-designed studies would be necessary.

• The Korean Journal of Ecology
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• v.22 no.3
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• pp.101-108
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• 1999

This survey was performed from March 1993 to March 1998, in order to clarify the relationships between water quality and topographical factor. The study sites were two reservoir basins; Kaesim and Jangchan in Iwon-myon, Okchon-gun, Chungcho'ngbukdo Province. Basin shape factors of Kaesim reservoir were at 0.030∼0.210 (mean value 0.090), those of Jangchan reservoir were at 0.217∼0.452 (mean value 0.325). The mean basin shape factor of Jangchan reservoir was 3.61 times larger than that of Kaesim reservoir because its stream width was narrower and mean stream length was shorter. In the correlation between distance from the source of stream (L) and basin area (A), Iwonchon basin was calculated as L=1.44A/sup 0.6/. Circularity ratio was 17.114 in Kaesim (22% of Kum River), and 7.444 in Jangchan. Elongation ratio was 0.357 in Kaesim, 0.636 in Jangchan and 0.282 in Kum River. Precipitation summation period of Jangchan was 1.54 times slower than that of Kaesim. Rainfall reaching time in each small basin was 337.53 min. in A'(Jangchan-ri) basin of Jangchan and 49.26 min in H (Iwon-ri) basin of Kaesim. In the relationship between watershed frequency (Df) and drainage density (Dd), the regression equation was Df=0.023Dd² in Kaesim and Df=0.189Dd² in Jangchan reservoir. As slope degree increased, DO became higher (Y/sub DO/=0.19X＋6.5927, r=0.8l), but COD(Y/sub COD/=-0.2092X＋9.7104, r=0.52) became lower. Total nitrogen was increased with the increase of basin shape factor and circularity ratio. Ratio of B/sub OD/ to COD was 1/1.2(Y/sub BOD/ = 1.2984 X/sub COD/-3.2004, r=0.9l).