• Journal of the Korean Home Economics Association
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• v.37 no.3
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• pp.175-191
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• 1999

The purpose of this study was to investigate the eating behavior and life habits of kindergarten children 5 to 7 years old in Chuncheon area. This study was conducted in December, 1996. Anthropometric indices(height, weight, skinfold thickness, mid-arm circumference) were measured and body mass index(BMI), Rohrer index, arm fat area were calculated to estimate children’s body fatness. Also the eating behavior and life habits were determined tv using questionnaire method. The results were as follows: Body fat rate of the children was almost normal according to Rohrer index and BMI. There was significant difference in birth weight between male and female. The problems of the eating behavior were frequent skipping breakfast and eating-out. The rate of the children who took snacks 2 times a day was 46.9％. Most children tended to take sweet snacks such as ice-cream, chocolates, cookies, and they tended to prefer meats and fishes to vegetables. The rate of breast feeding was 28.3％ and the rate of weaning foods prepared at home was 61.1%. Many children preferred indoor activities such as watching TV, toy furniture play, building block to outdoor activities such as roller-skating, cycling, jogging in their spare time. The rate of the children who took exercise regularly was 15％. Children tended to eat kimbap, fried chicken, ramyeon more frequently in various instant foods. The intake rates of fruit juice and barly tea were relatively high and children's favorite fruits were watermelon and mandarin orange. From this results, skipping breakfast, frequent eating-out and the monotony of food preference appears to cause imbalance in nutrient intakes of the children and to have bad influence on children’s health. Accodgingiy, the comprehensive nutrition education and proper modification program should be needed for the children and their parents to correct the eating behavior and life habits. The reasonable exercise programs are needed to motivate outdoor activities of the children, and the importance of breast feeding and weaning foods should be emphasized to lactating women and pregnant women.

• Journal of the Korean Electrochemical Society
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• v.13 no.4
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• pp.246-250
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• 2010

In this study, nano-crystallized $Al_2O_3$ was coated on the surface of $LiFePO_4$ powders via a novel dry coating method. The influence of coated $LiFePO_4$ upon electrochemical behavior was discussed. Surface morphology characterization was achieved by transmission electron microscopy (TEM), clearly showing nano-crystallized $Al_2O_3$ on $LiFePO_4$ surfaces. Furthermore, it revealed that the $Al_2O_3$-coated $LiFePO_4$ cathode exhibited a distinct surface morphology. It was also found that the $Al_2O_3$ coating reduces capacity fading especially at high charge/discharge rates. Results from the cyclic voltammogram measurements (2.5-4.2 V) showed a significant decrease in both interfacial resistance and cathode polarization. This behavior implies that $Al_2O_3$ can prevent structural change of $LiFePO_4$ or reaction with the electrolyte on cycling. In addition, the $Al_2O_3$ coated $LiFePO_4$ compound showed highly improved area-specific impedance (ASI), an important measure of battery performance. From the correlation between these characteristics of bare and coated $LiFePO_4$, the role of $Al_2O_3$ coating played on the electrochemical performance of $LiFePO_4$ was probed.

• Journal of Sport and Applied Science
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• v.2 no.1
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• pp.1-10
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• 2018

Today, the population of cycle participants is consistently increasing. Cycling is becoming not only a form of physical exercise but also a form of tourism in which cycle activities are related to visiting a particular destination. With the perspective of participation sport tourism, the purpose of this study is to investigate how the level of cycle tourists' participation affects their quality of life. An online survey link was sent to cycle participants to collect data. Out of the total 337 respondents, a total of 226 samples were used for the final analysis, disregarding those that were found to be inadequate or unreliable. For data analysis, frequency analysis, reliability test, validity, correlations, and regressions were employed with SPSS 22.0. For our first result, we found that the level of cycle participation did not significantly affect the quality of physical life. Second, the level of cycle participation did not have significant effect on the quality of mental life. Third, the level of cycle participation behavior did not have a significant effect on the quality of social life. Fourth, the level of cycle participation behavior did not have a significant effect on the quality of environmental life. Conclusions and political implications are discussed.

• Advanced Composite Materials
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• v.18 no.1
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• pp.61-75
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• 2009

The effect of porous matrix on thermal fatigue behavior of 3D-orthogonally woven SiC/SiC composite was evaluated in comparison with that having relatively dense matrix. The porous matrix yields open air passages through its thickness which can be utilized for transpiration cooling. On the other hand, the latter matrix is so dense that the air passages are sealed. A quantity of the matrix was varied by changing the number of repetition cycles of the polymer impregnation pyrolysis (PIP). Strength degradation of composites under thermal cycling conditions was evaluated by the $1200^{\circ}C$/RT thermal cycles with a combination of burner heating and air cooling for 200 cycles. It was found that the SiC/SiC composite with the porous matrix revealed little degradation in strength during the thermal cycles, while the other sample showed a 25% decrease in strength. Finally it was demonstrated that the porous structure in 3D-SiC/SiC composite improved the thermal fatigue durability.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.11a
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• pp.29-32
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• 1998

A new treatment of LiV$_3$O$_{8}$ has beer proposed for improving its electrochemical behavior as a cathode material secondary lithium batteries. Early in its development, the preparation method of LiV$_3$O$_{8}$ strongly influenced its electrochemical properties, such as discharge capacity, rate capability and cycling efficiency. In the present experiment, a new synthesis route has been applied to obtain LiV$_3$O$_{8}$ . Instead of the conventional high temperature technique leading to the crystalline form, a solution technique producing the amorphous form has been used. This material, after dehydration, shows an electrochemical performance exceeding that of the crystalline one. These measurements showed that the ultrasonic treatment process of crystalline LiV$_3$O$_{8}$ causes a decrease in crystallinity and considerable increases in specific surface area and interlayer spacing. So the ultrasonic method provides a convenient means for improving the electrochemical behavior of LiV$_3$O$_{8}$ as a cathode material for secondary lithium batteries.batteries.

• Economic and Environmental Geology
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• v.33 no.5
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• pp.353-365
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• 2000

After their first appearance on Earth, bacteria have exerted significant influence on geochemical behavior of elements. Numerous evidence of their control on geochemistry through geologic history has been observed in a variety of natural environments. They have mediated weathering rate, formation of secondary minerals, redox transformation of metals and metalloids, and thus global cycling of elements. Such ability of bacteria receives so considerable attention from microbiologists, mineralogists, geologists, soil scientists, limnologists, oceanographers, and atmospheric scientists as well as geochemists that a new and interdisciplinary field of research called 'geomicrobiology' is currently expanding. Some recent subjects of geomicrobiology which are studied extensively are as follows: 1) Functional groups distributed on bacterial cell walls adsorb dissolved cations onto cell surfaces by electrostatic surface complexation, which is followed by hydrous mineral formation. 2) Dissimilatory metal reducing bacteria conserve energy to support growth by oxidation of organic matter coupled to reduction of some oxidized metals and/or metalloids. They can be effectively used in remediating environments contaminated with U, As, Se, and Cr. 3) Bacteria increase the rate of mineral dissolution by excreting proton and ligands such as organic acids into aqueous system. 4) Thorough investigation on the effects of biofilm on geochemical processes is needed, because most bacteria are adsorbed on solid substrates and form biofilms in natural settings.

• Bulletin of the Korean Chemical Society
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• v.30 no.10
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• pp.2223-2226
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• 2009

Pristine and sulfur-doped (LiFe$PO_{3.98}S_{0.03}$) lithium iron phosphates were synthesized by a sol-gel method. The XRD pattern of the prepared materials suggested an orthorhombic structure with a Pnma space group and an absence of impurities. The Li/LiFe$PO_4$ or LiFe$PO_{3.98}S_{0.03}$ cells were employed for cycling studies at various temperatures (25, 50 and $60\;{^{\circ}C}$). In all cases, the Li/LiFe$PO_{3.98}S_{0.03}$ cell showed an improved performance with a stable discharge behavior of ~155 mA$hg^{-1}$. Nevertheless, pristine LiFeP$O_4$ cells presented poor discharge behavior at elevated temperatures, especially $60\;{^{\circ}C}$.

• Korean Journal of Materials Research
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• v.27 no.1
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• pp.25-31
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• 2017

This study investigates changes in the mechanical behaviors, especially hardness and indentation load-displacement curves, of thermal barrier coatings (TBCs) brought about by thermal shock. The TBCs on the Nickel-based bondcoat/superalloy was prepared with diameters of 25.4 mm and $600{\mu}m$ thickness. The results of thermal shock cycling test from $1100^{\circ}C$ of the highest temperature indicate that the thermal shock do not influence on the mechanical behavior, but a continuous decrease in porosity and increase in hardness were observed after 1200 thermal shock cycles; these changes are believed to be due to sintering of thermal barrier coating materials. The results that no degradation in the indentation load-displacement curves indicate that the coating shows good thermal shock resistance up to 1200 cycles at $1100^{\circ}C$ in air.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.11 s.242
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• pp.1480-1487
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• 2005

Metal matrix composites(MMCs) have been rapidly becoming one of the strongest candidates for structural materials fur many high temperature application. However, among the various high temperature environments in which metal matrix composites was applied, thermal shock is known to cause significant degradation in most MMC system. Due to the appreciable difference in coefficient of thermal expansion(CTE) between reinforcement and metal matrix, internal stresses are generated following temperature changes. Infernal stresses affect degradation of mechanical properties of MMC by causing microscopic damage in interface and matrix during thermal cycling. Therefore, the nondestructive evaluation on thermal shock damage behavior of SiC/A16061 composite has been carried out using ultrasonics. For this study, SiC fiber reinforced metal matrix composite specimens fabricated by a squeeze casting technique were thermally cycled in the temperature range 298$\~$673 K up to 1000cyc1es. Three point bending test was conducted to investigate the efffct of thermal shock damage on mechanical properties. The relationship between thermal shock damage behavior and the propagation characteristics of surface wave and SH-ultrasonic wave was discussed by considering the result of SEM observation of fracture surface.

• Journal of the Korean Electrochemical Society
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• v.5 no.4
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• pp.178-182
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• 2002

The electrochemical behavior of binder-free carbon anode, comprising of only artificial and natural graphite (AG and NG) particles, for intercalation and deintercalation of lithium ion $(Li^+)$ in aluminum chloride (AICI_3)-I-ethyl­3-methylimidazolium chloride (EMIC)-lithium chloride (LiCl)-thionyl chloride $(SOCI_2)$ room-temperature molten salt (RTMS) was studied. Binder-free carbon electrodes were fabricated using electrophoretic deposition (EPD) method. The binder-free carbon anodes provided a relatively flat charge and discharge potentials $(0\;to\;0.2V\;vs.\;Li/Li^+)$ and current capabilities $(250-340mAh{\cdot}g^{-1})$ for the intercalation and deintercalation of $Li^+$. Stability of the binder-free carbon anodes for intercalation and deintercalation of 50 cycles was confirmed.