• Physical Therapy Korea
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• v.5 no.1
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• pp.63-78
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• 1998

The decrease of muscle power and muscle size between twenties and seventies was about 30% and 40% respectively. The loss of muscle mass by aging resulted in the decrease of muscle power. The loss of muscle mass was due to the decrease of number of Type I fiber and Type II fiber and size of each muscle fiber. The aging skeletal muscle didn't show the loss of glycolysis capacity but showed 20% decrease of the oxidative enzymes and muscle vascularization. The vigorous endurance exercise training with graded intensity played a role in the vascular proliferation, increase of activity of oxidative enzymes and improvement of $VO_2$ max. The graded resistance exercise also played a role in the muscle hypertrophy and increase of muscle power, if it performed with adequate intensity and period. The exercise adaptation of aging skeletal muscle prevented it from sarcopenia, provided the activity of daily living with great effect and provided the aging related disease, that is Type II diabetes mellitus, arteriosclerosis, hypertension, osteoporosis and obesity, with great effect.

• Journal of the Korean Society of Clothing and Textiles
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• v.24 no.2
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• pp.173-184
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• 2000

The purposes of this study is for consideration of the flapper image through the culture and novels in Jazz Age(1919∼1929) of America. The back ground of flapper fashion was Jazz. Jazz was one of the cultural languages which expressed liveness, noise, salacity, harmony of primitivity, modernity, innocence and freedom. In processing American had gotten economic power, the Jazz Age had new mood which was combined materialism and realitism. Environmental changes of life styles and development of mass culture of modern big cities could aid the birth of modern girls, flappers. They became the main group of new consumer and mass culture in new consciousness and freedom with independence. Their characteristics are confirmed from Fitzgerald's novels, This Side of Paradise and The Great Gatsby. As the results of above, the consciousness of flapper were rebellious attitude, liberalism and actualism. The designs of flapper fashion were expressed by simplicity, functionality, nudity and rhythm. The flapper images are as follows: First, they expressed modern image as a rebellious attitude. Second, flapper had a sensual image of freedom through rhythmical and speedy expression. Third, premature image for pursuing youth could be found. Therefore the changes of culture and women's life styles are very important points for fashion studies and the connecting fashion and other fields like novels is needed also for it.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2009.05b
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• pp.61-64
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• 2009

This study is reviewed fire resistance characteristics of high strength concrete according to changes in PP fiber mixing ratio and type of fine aggregate, and the results can be summarized as follows. As fire resistance characteristics, all plain crushed sands prevented spalling regardless of increase in mixing ratio of PP fiber. Mixtures other than the plain showed satisfactory spalling prevention when 0.05 % or more of PP fiber was mixed. After the fire resistance experiment, the plain showed 5.5 % of mass loss rate when fiber was not mixed and others could not be measured. According to increase in mixing ratio of fiber, river sand with fineness modulus of 2.2 showed most satisfactory result of 34 %${\sim}$42 %. Mass loss rate after fire resistance experiment was most satisfactory at about 10 % in the plain crushed sand without mixing of fiber, and all other mixes with 0.05 % PP fiber or more showed 5${\sim}$10 % loss rate.

• Structural Engineering and Mechanics
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• v.69 no.1
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• pp.33-42
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• 2019

Thermal cracks are cracks that commonly form at early ages in mass concrete. During the concrete pouring process, the elastic modulus changes continuously. This requires the time domain to be divided into several steps in order to solve for the temperature, stress, and displacement of the concrete. Numerical simulations of thermal crack propagation in concrete are more difficult at early ages. To solve this problem, this study divides crack propagation in concrete at early ages into two cases: the case in which cracks do not propagate but the elastic modulus of the concrete changes and the case in which cracks propagate at a certain time. This paper provides computational models for these two cases by integrating the characteristics of the extended finite element algorithm, compiles the corresponding computational programs, and verifies the accuracy of the proposed model using numerical comparisons. The model presented in this paper has the advantages of high computational accuracy and stable results in resolving thermal cracking and its propagation in concrete at early ages.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.7
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• pp.1116-1123
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• 2021

Oil spilled in seawater undergoes physical and chemical changes as well as biological degradation through various weathering processes, such as evaporation, diffusion, dispersion, emulsification, dissolution, oxidation, and sedimentation. Evaporation is one of the most immediate and prompt weathering processes, and it has the greatest influence on majority of pollutants. In this study, the evaporation characteristics of different oil samples were studied; the volatilization characteristics of gasoline, kerosene, and diesel were compared at average seawater (25 ℃) and near-equator (35 ℃) temperatures. The oil samples were pre-treated and then collected at regular intervals. Gas chromatography-mass spectrometry analysis was performed, and the changes in the amount of the hydrocarbons were calculated.

• Nuclear Engineering and Technology
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• v.54 no.5
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• pp.1874-1889
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• 2022

In this study, we evaluate the thermal-hydraulic performance and economics of Printed Circuit Heat Exchanger (PCHE) according to the channel types and associated shape variables for the design of recuperators with Sodium-cooled Fast Reactors (SFRs). To perform the evaluations with variables such as the Reynolds number, channel types, tube diameter, and shape variables, a code for the heat exchanger is developed and verified through a comparison with experimental results. Based on the code, the volume and pressure drop are calculated, and an economic assessment is conducted. The zigzag type, which has bending angle of 80° and a tube diameter of 1.9 mm, is the most economical channel type in a SFR using CO₂ as the working fluid. For a SFR using N₂, we recommend the airfoil type with vertical and horizontal numbers of 1.6 and 1.1, respectively. The airfoil type is superior when the mass flow rate is large because the operating cost changes significantly. When the mass flow rate is small, volume is a more important design parameter, therefore, the zigzag type is suitable. In addition, we conduct a sensitivity analysis based on the production cost of the PCHE to identify changes in optimal channel types.

• Korean Journal of Exercise Nutrition
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• v.17 no.2
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• pp.43-48
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• 2013

This study aims to investigate changes in plasma lipid concentrations and appetite-regulating hormone levels after a 4% body fat reduction using a 9-week intervention involving aerobic exercise, a fat-oxidizing agent, and diet limitation. After the 9-week intervention, the aerobic exercise plus hydroxycitric acid (EX+HCA), exercise (EX), and diet limitation (DIET) groups achieved the target 4% body fat reduction from the baseline value. None of the plasma lipid indicators showed significant intergroup differences, indicating that plasma lipid levels are not influenced by body weight regulation. With regard to appetite-regulating hormones, no significant intergroup differences were observed in glucose, insulin, or glucagon-like peptide-1 levels, unlike ghrelin and leptin. Ghrelin levels in particular tended to decrease in the DIET group and increase in the HCA+EX and EX groups. Leptin levels significantly decreased in the HCA+EX and EX groups, whereas no differences were observed in the DIET group. Such results indicate that exercise alone without the administration of obesity diet supplements induces elevation in ghrelin levels and reduction in leptin levels, but that diet restriction alone does not influence changes in leptin levels. Taken together, we could not confirm any synergic effects arising from the use of a fat-oxidizing agent during an exercise program to control body weight. Furthermore, diet limitation unsupported by exercise had no effect on muscle mass reduction or appetite-regulating hormone levels; thus, it is not recommended as an effective body weight control method.

• Journal of Korean Medicine for Obesity Research
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• v.24 no.1
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• pp.102-110
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• 2024

This study reports the clinical effects of Korean medicine treatments, herbal medicine, modified fasting, and space spinal conduction exercise and manipulation (SSCEM) on adolescent obesity patient. A 16-year-old male with a body mass index (BMI) 35.5 kg/m² was diagnosed with class III obesity. We prescribed herbal medicine and modified fasting alternately three times over a period of five months. Additionally, Korean medicine treatments and SSCEM were performed during the treatment period. After treatment, there was a decrease in body weight by 19.86%, from 115.8 kg to 92.8 kg, BMI from 35.5 kg/m² to 28.6 kg/m², and body fat mass from 38.1 kg to 17.0 kg. The results of this study showed that Korean medicine treatments, herbal medicine, modified fasting, and SSCEM could be useful in influencing changes in body composition among obese adolescents.

• Food Science of Animal Resources
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• v.44 no.5
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• pp.1096-1107
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• 2024

This study investigated the changes in volatile compounds in chicken flesh after boiling at various pHs (6.0-9.0) and after chilling storage (4.0±1.0℃) for 7 d. The volatile compounds were assessed qualitatively and quantitatively by using a headspace gas chromatography-mass spectrometry analysis. Twenty-one volatile compounds were discovered and categorized as amine, aldehyde, alcohol, ketone, acid, and furan. One type of amine, (2-aziridinylethyl) amine, was the most prevalent volatile component, followed by aldehyde, ketone, aldehyde, acid, ester, and furan. The results showed that the quantity and quality of the volatile compounds were influenced by a pH of the boiling medium. Additionally, the types and volatile profiles of the chicken were altered during chilling. In particular, in the chicken that was boiled at a pH of 8.0, the hexanal (an aldehyde) content increased the most after 7 d of chilling. Moreover, various alcohols formed after the 7 d of chilling of the chicken that was boiled at pHs of 8.0 and 9.0. Because of the oxidation and degradation of fat and proteins, the most altering volatile compounds were the reducing amines and the increasing aldehydes.

• Journal of the Korean Chemical Society
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• v.59 no.3
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• pp.233-237
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• 2015

The effect of ultrasonication on PTFE and its composites with zeolite and fluoroplast F-4NTD-2 was studied. Ultrasonication was found to cause changes in the supramolecular structure, and consequently, the tensile strength, relative elongation, and mass wear rate. Changes in the topology of the materials following ultrasonication were investigated by scanning electron microscopy. The optimum enhancement of the desired properties was found in the PTFE composite containing 2% activated zeolite.