• Proceedings of the Korea Concrete Institute Conference
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• 2002.10a
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• pp.809-814
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• 2002

Recently, the properties of early-age concrete are increasingly important because these properties directly influence the behavior of early-age concrete structures including stress and cracking behavior. Nevertheless, the studies on early-age concrete are limited to strength and temperature development. The purpose of present study is to propose a simple and rational method which can predict the stress and strain behavior of young age concrete. A series of test have been done to measure the temperature development, strains and stresses in concrete members. The concept of equivalent age was used to define the degree of hydration and this degree of hydration was used to calculate the strength and elastic modulus. The critical degree of hydration and thermal expansion coefficient were calculated using experimental data. It is seen that the critical degree of hydration range from 0.05 to 0.11 based on the measuring method. The thermal expansion coefficient was calculated based on the measured non-mechanical strain and it is found that the coefficient decreases slightly with the increase of age. The consideration of critical degree of hydration in calculating stresses gives more accurate results. The present study provides useful method and data in evaluating early-age behavior of concrete structure.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2002.11a
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• pp.11-15
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• 2002

This study is intended to analyze the relationship between the rebound value of P type schmidt hammer and the compressive strength for a quality control of concrete. According to the results, the compressive strength of standard curing specimen increases in proportion to age, but that of air curing specimen hardly increases after 28 days. The rebound value of P type schmidt hammer, however, increases due to carbonation of concrete in air curing specimen. The correlativity between the rebound value and the compressive strength is very favorable in the case of standard curing specimen, but drops remarkably in the case of air curing specimen. Thus, as application of age coefficient is required for exact estimation of the compressive strength, the age coefficient is derived from this study. The age coefficient of P type schmidt hammer is higher at the age of 3 and 7days, and drops significantly, compared with the age of 28days. And it is lower before 28days than that of N type schmidt hammer suggested in Japan, and shows the similar tendency after 28days.

• Journal of the East Asian Society of Dietary Life
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• v.4 no.1
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• pp.37-47
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• 1994

A survey on images and consumption for Instant food for 450 homemakers in Ullungdo, Hansando and Daegu area were summarized as follows. 1) The tought of Homemakers food took 'easy to cook' and 'save time' as the best advantage in the image on instant food, while 'tasty' as the lowest one. It appeared that characteristic variables as household income, homemaker's education, homemaker's age, and area had influence on the image about instant food. 2) Processed food(ham, sausage)was purchased the most, while fermented food(kimchi, gochuchang) was purchased the least. It appeared that characteristics variables as household income, homemaker's education and homemaker's age had influence on the purchasing degree of instant food. 3) There were positive correlation coefficient between homemaker's image on instant food and household income(0.247) and area(0.211). There were negative correlation coefficient between homemaker's image on instant food and homemaker's age(-0.171). 4) Homemaker's purchasing degree about instant food had positive correlation coefficient with homemaker's image on instant food(0.389), household income(0.247) and area(0.211)and had negative correlation coefficient with homemaker's age(-0.190). 5) Fat intake had positive correlation coefficient with homemaker's purchasing degree(0.281) and homemaker's image(0.144) on instant food. Energy intake had positive correlation coefficient with homemaker's purchasing degree(0.206) and homemaker's image(0.138) on instant food.

• Journal of Ginseng Research
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• v.19 no.2
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• pp.165-170
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• 1995

This study was carried out to investigate the correlation of agronomic characters, their path coefficients in 2, 3 and 4-year old ginseng plants, and to provide a useful information for ginseng breeding. Correlation coefficients between stem fen변h, number of leaves and number of Iraflets in 2-year age, and stem diameter and leaf length in 3-year age showed highly significant correlation with number of fruits and root weight in 4-year age. The path coefficient analysis indicated that stem length and number of leaflets might give indirect effects on root weight regardless of plant age. On the other hand, stem length and number of leaflets in 2-year age and, stem diameter and leaf length in 3-year age showed direct effects on root weight in 4-year old ginseng. These results may be used for selection of high-yielding ginseng plants. Key words Selection information, correlation and path coefficient analysis.

• Journal of the Korea institute for structural maintenance and inspection
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• v.12 no.6
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• pp.173-179
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• 2008

This paper aims to calculate age coefficient of ultrasonic pulse velocity by non-destructive test. When concrete compressive strength is measured by non-destructive test, rebound test hammer method is applied to estimate age coefficient depending on the course of time after concrete casting, but ultrasonic pulse velocity method is not applied in the process. Although it is necessary to consider age coefficient with change of ultrasonic pulse velocity of concrete depending on aging, there have been little attempts to apply that method. The experiments were conducted to calculate aging effects which will be applied to establish the formula of measuring concrete strength. As a result of experiments, it was found that ultrasonic pulse velocity showed radical changes depending on concrete hardening in comparison with initial standard values. So, it was concluded that age coefficient must be applied to calculate strength. In conclusion, age coefficient of ultrasonic pulse velocity of concrete was suggested on the basis of experimental results.

• Health Policy and Management
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• v.12 no.1
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• pp.84-101
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• 2002

This study collected and analyzed the datum related to consultation fee in National Health Insurance Corporation and characteristics of dental clinics for 819 dental clinics in Daegu and Kyungpook districts to specify the distribution and concentration rate of health insurance consultation fee and the critical elements of insurance consultation fee income. The average health insurance consultation fee per one dental clinics is 77.2 million won and the case of women dentists is 78.7 million won. That is higher than 79.9 million won that the case of man dentist. According to age, under 39 is 85.5 million won that is highest, declining little by little above 60s the number decreased to merely 23.9 million won. And the dentists whose business years from 5 to 10 are the highest and declining gradually. The more of engaging members to dental clinics is the larger the income. The average insurance consultation fee of Daegu province is 69.3 million won, but that of Kyungpook is 89.6 million won. Decile distribution ratio of dental clinics consultation fee income is 0.526 and Gini coefficient is 0.303. Decile distribution ratio of Daegu district is 0.489, Gini coefficient is 0.320. This explain the larger inequality compared with Kyungpook(0.623, 0.273). With age, Gini coefficient of below 39 is 0.260, the higher age is, the larger the number is, up to abode 60 the coefficient is 0.504, the degree of inequality is most extremely. insurance consultation fee and the number of cases of consultation is related to the age of dentists, duration of practice, the number of dentists and staffs engaging and provinces. That is, the lesser the age is, the longer the years of engaging are, the more the number of dentists and staffs we, the larger insurance consultation fee income and the number of cases of consultations we. And the fee fur one case is closely related to age and provinces. The fee for one case is higher in lower age, and that of in Daegu dental clinics is higher than in Kyungpook.

• Water for future
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• v.29 no.4
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• pp.223-231
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• 1996

For the most efficient operation of water mains, 124 head losses in domestic water supply steel mains were measured to provide the values of friction coefficient and the variable affecting the deterioration rate of Hazen Williams' and Darcy-Weisbach's friction coefficient. The experimental results show that pipe age is governing the friction coefficient of large mains (Diameter > 1100 mm). On the other hands, pipe age and pipe diameter are affecting the variation of carrying capacity for small mains (Diameter < 1100 mm). The friction coefficient of water mains in foreign countries is higher than that in Korea by about 5 to 10 in Hazen Williams' C value. The growing rate of roughness height of domestic water main is about 0.41 mm/year which is higher than the average of United States of America. So further study is required to find out what causes the serious deterioration rate.

• Journal of the Korea Concrete Institute
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• v.24 no.6
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• pp.715-726
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• 2012

Since strength and diffusion coefficient of concrete, representative concrete properties that in change with age, the time effect must be considered in the analysis of chloride penetration. In this study, an evaluation of correlation between accelerated diffusion coefficient, apparent diffusion coefficient, and compressive strength in high performance concrete with various mineral admixtures such as ground granulated blast furnace slag, fly ash, and silica fume was performed. For this work, thirty mix proportions were prepared. Accelerated diffusion coefficients at the age of 28, 91, 180, and 270 days were evaluated. For apparent diffusion coefficient, submerging test for 6 months was performed. For evaluation of compressive strength with ages, the compressive strength test was carried out at an age of 7, 28, 91, 180 days. The results of accelerated diffusion coefficient, apparent diffusion coefficient, and strength were compared, and the correlation was analyzed considering time dependency. From this study, linear relationship between accelerated diffusion and apparent diffusion coefficient were obtained regardless of concrete age. The linear relations were also observed in strength-accelerated diffusion coefficient and strength-apparent diffusion coefficient regardless of concrete age.

• Structural Engineering and Mechanics
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• v.72 no.6
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• pp.737-746
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• 2019

Concrete mechanical properties change constantly with age, temperature, humidity and the other environmental factors. This research studies the effects of temperature and age on the development of concrete elastic modulus by a series of prism specimens. Elastic modulus test was conducted at various temperatures and ages in the laboratory to examine the effects of temperature and age on it. The experimental results reveal that the concrete elastic modulus decreases with the rise of temperature but increases with age. Then, a temperature coefficient K is proposed to describe the effects of temperature and validated by existing studies. Finally, on the basis of K, analytical models are proposed to determine the elastic modulus of concrete at a given temperature and age. The proposed models can offer designers an approach to obtain more accurate properties of concrete structures through the elastic modulus modification based on actual age and temperature, rather than using a value merely based on laboratory testing.

• Journal of Fashion Business
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• v.19 no.2
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• pp.1-22
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• 2015

This study provides the basic data for clothing construction of teen girls by researching and analyzing the characteristics of physical changes of tween generation school girls between 8 to 14 age. Fifty eight items of direct measurements and 61 calculated-items based on the 6th Korean National Physical Standard Reports were used. Results were obtained by using ANOVA, SNK test, coefficient of variation and growth rate of age groups. Significant differences were found among all the age groups, and were in the increasing order of height > length > width > depth > circumference. The growth rate was found in the increasing order of bust depth > hip width > N.P. to B.P. > hip circumference > bust circumference and thigh circumference. There were dramatic increases in height, circumference and width during the age of 8~9 and 10~11, in length during age of 10~11, and in depth during age of 8~11. The growth of the vertical measurement items is slowing at the age of 13. The individual differences were great in the vertical measurements at the age of 8 and 9 and in the horizontal measurements, at the age of 10. The increasing growth of bust and hip than waist gave it a curved shape.