• Journal of the Korean Institute of Gas
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• v.17 no.5
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• pp.81-86
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• 2013

Accidents of dust explosion has been occurred in various industries as a plastics, pharmaceuticals, timber, grain storage, solid fuels and chemicals. In this study, the silo dust, hammer mill dust and Nyusong dust in the manufacturing process of the particle board to utilize west wood, which were selected for this experiment and were evaluated the characteristics of dust explosion. The explosion characteristics such as a maximum explosion pressure, explosion index, lower explosive limit, and minimum ignition energy in suspended dust of the wood by Siwek 20 L apparatus were measured and evaluated for the experiment. The results of this study can be used the process safety measures to prevent accidents of fire and explosion in the suspended dust of wood.

• Korean Journal of Applied Biomechanics
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• v.30 no.2
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• pp.185-195
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• 2020

Objective: The purpose of this study was to identify recent domestic and international research trends regarding shoes carried out in biomechanics field and to suggest the direction of shoe research later. Method: To achieve this goal of research, the Web of Science, Scopus, PubMed, Korea Education and Research Information Service and Korean Citation Index were searched to identify trends in 64 domestic and international research. Also, classified into the interaction of the human body, usability evaluation of functional shoes, smart shoe development research, and suggested the following are the suggestions for future research directions. Conclusion: A study for the coordination of muscle activity, control of motion and prevention of injury should be sought by developing shoes of eco-friendly materials, and scientific evidence such as physical aspects, materials, floor shapes and friction should be supported. Second, a study on elite athletes in various sports is needed based on functional shoes using new materials to improve their performance along with cooperation in muscle activities and prevention of injury. Third, various information and energy production are possible in real time through human behavioral information, and the application of Human Machine Interface (HMI) technology through shoe-sensor-human interaction should be explored.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.381-381
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• 2010

$(ZrO_2)_{0.66}(HfO_2)_{0.34}$ thin films as gate dielectrics have been proposed to overcome the problems of tunneling current and degradation mobility inachieving a thin equivalent oxide thickness. An extremely thin $SiO_2$ layer is used in order to separate the carrier in MOSFET channel from the dielectric field fluctuation caused by phonons in the dielectric which decreases the carrier mobility. The electronic and optical properties influenced the device performance to a great extent. $(ZrO_2)_{0.66}(HfO_2)_{0.34}$ dielectric films on p-Si (100) were grown by atomic layer deposition method, for which the conduction band offsets, valence band offsets and band gapswere obtained by using X-ray photoelectron spectroscopy and reflection electron energy loss spectroscopy. The band gap, valence and conduction band offset values for $(ZrO_2)_{0.66}(HfO_2)_{0.34}$ dielectric thin film, grown on Si substrate were about 5.34, 2.35 and 1.87 eV respectively. This band alignment was similar to that of $ZrO_2$. In addition, The dielectric function (k, $\omega$), index of refraction n and the extinction coefficient k for the $(ZrO_2)_{0.66}(HfO_2)_{0.34}$ thin films were obtained from a quantitative analysis of REELS data by comparison to detailed dielectric response model calculations using the QUEELS-$\varepsilon$(k, $\omega$)-REELS software package. These optical properties are similar with $ZrO_2$ dielectric thin films.

• Korean Journal of Food Science and Technology
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• v.16 no.3
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• pp.314-318
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• 1984

Rheological properties of gelatinized chestnut starch solution were investigated with a narrow gap rotational viscometer. The starch solutions at 1.2-1.8% concentration showed pseudoplastic behaviour with yield stress. At higher concentrations (1.65 and 1.8%), the starch solution showed more pseudoplastic tendency and time-dependent characteristics. Values of yield stress were small and independent of concentrations 1.2, 1.35 and 1.5%. Significant increase of yield stress was observed at 1.65% concentration. Consistency index was exponentially dependent on concentration and temperature. The activation energy for 1.65% starch solution was about 5 Kcal/g.mol.

• Journal of Community Nutrition
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• v.3 no.1
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• pp.14-20
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• 2001

A cross-sectional study to determine dietary intake and plasma triglyceride total cholesterol LDL-cholesterol and HDL-cholesterol of 185K Korean men was conducted across three different age groups The younger group (age 21 to 34) was significantly (p<0.001) taller but showed lower (p<0.05) percent body fat than the older group (age 45 to 60) Weight and body mass index was not different among age groups. Older men showed significantly(p<0.01) lower energy and total fat intake than younger men Besides macronutrients, most participants consumed an adequate amount of micronutrients but calcium consumption of the middle age group (age 35 to 44) was less than 75% of RDA In older men plasma triglyceride(207.8$\pm$155.5 mg/dl) total cholesterol (201.4$\pm$40.0 mg/dl) and LDL-cholesterol(106.0$\pm$32.7 mg/dl) concentrations were significantly hight(p<0.001) than in younger men wereas no significant difference was observed in HDL-cholesterol concentration Subjects with a higher BMI(bMI$\geq$25.0) showed significantly higher (p<0.001) triglyceride(200.2$\pm$107.6 mg/dl) total cholesterol(211.0$\pm$40.1 mg/dl) LDC-cholesterol(118.16$\pm$35.5 mg/dl) concentrations and lower(p=0.001) HCL-cholesterol concentration (52.8$\pm$15.9 mg/dl) than subjects with lower BMI(BMI<23.0) Dietary intake of fat cholesterol did not show significant associations with any of the plasma lipid profiles. However, anima fat intake was significantly (p<0.05) correlated with plasma total cholesterol and triglyceride concentrations in the older age group. On the hand percent body fat was correlated (p<0.05) with all of the plasma lipid and lipoprotin concentrations examined for all age groups Results indicate both dietary intake and percent body fat are important determinants of the plasma lipid concentrations is the elderly but only percent body fat or body mass could be valid predictors for the plasma lipid concentrations of the younger age group.

• Korean Journal of Community Nutrition
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• v.9 no.3
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• pp.292-302
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• 2004

The nutritional status of middle-aged overweight and control normal subjects were evaluated for the purpose of providing the background information of the degenerative disease control. A survey was conducted with 293 healthy subjects (121 males and 172 females) between the ages 40-64. The average BMI (body mass index) of male subjects was 24.5 $\pm2.75$, and that of females was 23.5 $\pm2.87$. The average values of WHR (waist-hip ratio) were 0.88 $\pm0.04$, for males and 0.82 $\pm0.07$, for females. The normal BMI group (BMI 18.5-22.9) comprised 28.9% of males and 47.1% of females. The percentage of overweight subjects (BMI 23-24.9) was 26.4% of males and 30.8% of females. The obese group (BMI ＞ 25) was 44.6% of males ana 22.1% of females, showing the greater rate of obese state among male subjects. The average energy intakes were 76.6 $\pm14.9$% for males and 77.8 $\pm12.6$, % for females, protein intakes were 108.0 $\pm24.6$% for males and 111.2 $\pm22.7$, % for females of the RDA levels. The average intakes of other nutrients were above the 75% of RDA levels except calcium. The average nutrient intakes of the three subgroups according to their BMI values were not different for both males and females. There were weak correlations between obesity and blood biochemical indices. There were positive correlations between BMI or WHR and hemoglobin, hematocrit, fasting glucose, total cholesterol, triglyceride, AST or ALT. There were negative correlations between BMI or WHR and HDL-cholesterol. These results suggest that the obesity rate of middle-aged is an influential factor of chronic disease. The middle-aged subjects of this study with higher educational and socioeconomic background tend to have desirable nutrition knowledge and attitude, but the application of their knowledge or attitude was relatively poor.

• Journal of Nutrition and Health
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• v.38 no.7
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• pp.578-585
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• 2005

Maternal zinc deficiency is relatively common worldwide, but its consequences for pregnancy outcome are not established. The purpose of this study was to examine the effect of zinc status in the second trimester on pregnancy outcome. Subjects were 248 pregnant Korean women (25-28 wk gestation). Cord blood was collected from subgroup of 69 women and pregnancy outcome data were obtained from 185 babies. Anthropometry measurement, dietary intake, and biochemical characteristics of pregnancy and cord serum substances were measured. The subjects were divided into quartiles on the basis of maternal serum Zn concentration; $ZnQ_1$ (< 25 percentile), $ZnQ_2$ ($26\~50$ percentile), $ZnQ_3$ ($51\~75$ percentile), and $ZnQ_4$ ($76\~100$ percentile). Zn groups were compared in terms of various maternal factors, concentrations of cord serum substances, and pregnancy outcome. Maternal serum Zn concentration was $118.4\;{\pm}\;35.5\;{\mu}g/dl$ as mean. Intake of Zn was lower than Korean RDA. The rate of Zn deficiency among all subjects was $8.5\%$. Maternal serum Zn levels belonged to normal range. Cord serum Zn level was about $154.7\%$ of maternal serum level. Intakes of energy, calcium, iron, folic acid, and riboflavin did not meet the Korean RDA for pregnant women by gestational age. The mean birth weight of neonates is 3083 $\pm$ 697 g, of whom $9.1\%$ were of low birth weight (< 2,500 g). Maternal serum Zn level was positively correlated with pre-pregnancy weight, pre-pregnancy body mass index, and vitamin C intake (p < 0.05). $ZnQ_1$ group had significantly lower maternal serum iron concentration and higher cord serum cholesterol than those in other groups. Maternal serum Zn level, cord serum Zn level, and dietary Zn intake were no related to the pregnancy outcome. The birth weight had a correlation with the maternal hemoglobin and albumin concentration. In conclusion, at this study, we could not find the association with maternal Zn status in 2nd trimester and pregnancy outcome.

• Nutritional Sciences
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• v.5 no.1
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• pp.13-19
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• 2002

A mutation in the promoter region of uncoupling protein 3 (UCF3), specifically the -55C longrightarrow T transition, may influence an individual's energy metabolism and body weight. The objective of this study was to investigate the effect of a weight reduction program on endocrine functions and body fat distribution, related to UCP3 promoter genotype. Ninety overweight pre-menopausal female subjects participated in the weight reduction program at Yonsei University Hospital, and were placed on a calorie-restricted diet (300 kcal less than their daily requirements) for 12 weeks. After 12 weeks, all subjects on the program lost approximately 5% of their initial body weights and had lower Body Mass Index (BMI) values. Among the 90 women, 56 had a normal (without mutation) UCP3 genotype, while 34 women had mutations in the promoter region of UCP3. Despite similar weight reductions in both groups, a significantly higher decrease in abdominal adipose tissue was observed in the normal UCP3 genotype group, compared to the group with mutations. In particular, there was a significant reduction of fat at the lumbar 1 (Ll) level in the without-mutation group. Serum levels of total cholesterol, apolipoprotein Al were significantly decreased in the without-mutation group, by 4.4% and 5.7% respectively. Serum levels of hormones were not significantly changed in both groups artier the intervention. However, in the group without the mutations, the leptin level significantly reduced by 23.4% (p<0.001). Serum free fatty acid (FFA) concentration was significantly increased in the group with mutation following the weight reduction program. On the other hand, FFA responses were shown similar increases in both groups. In conclusion, although no difference was found in the magnitude of weight reduction in both groups, there were significant differences in body fat distribution and in endocrine function between the groups.

• Journal of the Earthquake Engineering Society of Korea
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• v.2 no.1
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• pp.95-111
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• 1998

In this study, the concepts and procedures of the seismic damage analysis methods are examined for both the element-level and the system-level. The seismic damage analysis at the element-level is performed for several example structures using existing method for structural elements or single-degree-of-freedom (SDOF) systems such as the Park and Ang method. In order to analyze seismic damage at the system-level, two types of procedures are used. In the first type of procedure, the system-level seismic responses can be estimated by using the system representative response method(SRRM), or the equivalent SDOF system response method (ESDOF-SRM). Then, the system-level seismic damage is analyzed from the system-level seismic responses using existing method for structural elements or SDOF systems. IN the second type of procedure, the system-level seismic damages are analyzed using the element damage combination method (EDCM) combing the element-level damage indices determined by existing method. To compare tendency of the seismic damage analysis using each methods, example analysis is accomplished for several cases of different structures and different earthquake excitation.

• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.1
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• pp.165-174
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• 2010

In this paper, a two-phase structural health monitoring system using acceleration response signatures are presented to firstly alarm the change in structural condition and to secondly detect the changed location for full-scale concrete girder bridges. Firstly, Mihocheon Bridge which is a two-span continuous concrete girder bridge is selected as the target structure. The dynamic response features of Mihocheon Bridge are extracted by forced vibration test using bowling ball. Secondly, the damage alarming occurrence and the damage localization techniques are selected to design two-phase structural health monitoring system for Mihocheon Bridge. As the damage alarming techniques, auto-regressive model using time-domain signatures, correlation coefficient of frequency response function and frequency response ratio assurance criterion are selected. As the damage localization technique, modal strain energy-based damage index method is selected. Finally, the feasibility of two-phase structural health monitoring systems is evaluated from static loading tests using a dump truck.