• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2002년도 가을 학술발표회 논문집
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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.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2002년도 학술.기술논문발표회
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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.

• 동아시아식생활학회지
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• 제4권1호
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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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• 제19권2호
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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.

• 한국구조물진단유지관리공학회 논문집
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• 제12권6호
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• pp.173-179
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• 2008

비파괴시험에 의한 콘크리트 압축강도 추정시 반발경도법은 콘크리트 타설 후 시간경과에 따라 재령계수를 적용하고 있으나 초음파속도법은 적용되지 않고 있다. 재령경과에 따른 콘크리트 초음파속도의 변화에 대한 재령계수 적용의 필요성에 대하여 검토해야함에도 불구하고 그에 대한 연구가 거의 없는 실정이다. 따라서 본 연구는 콘크리트 초음파속도를 측정하여 강도 추정식에 적용될 재령계수를 산정하기 위한 실험을 실시한 결과, 초음파속도는 콘크리트 경화에 따라 재령 초기 기준치에 비교하면 급격한 변화를 보여 재령계수를 반드시 적용해야 한다는 것을 알 수 있었으며 실험결과에 의해 콘크리트 초음파속도의 재령계수를 제안하였다.

• 보건행정학회지
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• 제12권1호
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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.

• 물과 미래
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• 제29권4호
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• pp.223-231
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• 1996

보다 효율적인 관로운영에 필수적인 통수능 변화 및 영향인자 산정을 위하여 국내 도송수강관에 대하여 124개의 Hazen Williams및 Darcy-Weisbach 마찰계수를 실측, 분석하였다. 그 결과 국내 도송수강관은 국외의 마찰계수 변화형태와 유사한 경향을 보이며 관경이 클수록 (Diameter>1100mm) 통수능은 관령에 많은 영향을 받으나 관경이 작을수록 관경과 관령에 동시에 영향을 받는다는 사실을 알았다. 또한 Hazen Williams의 C 값은 외국에 비해 약 5-10 정도 작은 것으로 나타났으며, 조도높이의 성장률은 약 0.41 mm/년으로 관의 통수능이 외국에 비해 빨리 저하한다는 사실이 밝혀져 그 원인 파악 및 통수능 산정기준을 재 검토해야 할 것으로 판단되었다. 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.

• 콘크리트학회논문집
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• 제24권6호
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• pp.715-726
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• 2012

콘크리트의 대표적 물성치인 강도 및 염화물 확산계수는 재령에 따라 변화하며, 염화물 침투 해석시 이러한 영향들이 고려되고 있다. 이 연구는 다양한 혼화재료 (고로슬래그 미분말, 플라이애쉬, 실리카 퓸)을 포함하는 고성능콘크리트의 촉진염화물 확산계수, 겉보기 염화물 확산계수, 강도 특성을 재령에 따라 실험적으로 도출하고 그 상관성을 분석하는데 목적이 있다. 이를 위해 30개의 배합을 가지는 고성능 콘크리트가 제작되었고, 재령 28일, 91일, 180일, 270일에 대한 촉진확산계수를 실험적으로 도출하였으며, 또한 동일배합에 대하여 침지 6개월 이후의 겉보기 확산계수가 도출되었다. 재령에 대한 강도 특성을 평가하기 위해, 재령 7일, 28일, 91일, 180일에 대한 강도시험이 수행되었다. 시간 의존적인 촉진확산계수의 변화가 겉보기 확산계수 및 강도와 비교되었으며, 각각의 상관관계가 재령에 대하여 분석되었다. 이 연구를 통하여 겉보기 확산계수와 촉진확산계수는 재령에 큰 영향을 받지 않으면서 선형적인 상관성이 도출되었다. 또한 강도와 촉진확산계수 그리고 강도와 겉보기 확산계수에서도 재령에 큰 영향을 받지 않는 선형적인 관계가 도출되었다.

• Structural Engineering and Mechanics
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• 제72권6호
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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.

• 패션비즈니스
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• 제19권2호
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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.