• Journal of the Korea Concrete Institute
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• v.12 no.5
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• pp.25-34
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• 2000

When concrete is placed underwater, it is diluted with separating cementitious material and as a result the quality of concrete becomes poor. To solve this problem, antiwashout underwater concrete is increasingly used for the construction and repair of the concrete structure underwater. The objective of this study is to investigate the characteristics of antiwashout underwater concrete as to the mix proportion, casting and curing water through experimental researches. The unit weight of water and cement, water-cement ratio, fine aggregate ratio, unit weight of antiwashout underwater agent and superplasticizer, and casting and curing water were chosen to measure the suspended solids, pH, air contents, slump flow, unit weight of hardened concrete, and compressive strength. From this study, the incremental modulus at mix proportion design and unit weight of antiwashout underwater agent were increased more than fresh water, and it is a optimum mix proportion that the unit weight of water(and cement) is 230kg/$\textrm{m}^3$(460kg/$\textrm{m}^3$), waterOcement ratio is 50%, fine aggregate ratio is 40%, unit weight of antiwashout underwater agent is 1.2% of water contents per unit weight of concrete, and unit weight of supeplasticizer is 2.5% of cement contents per unit weight of concrete when the antiwashout underwater concrete is used for the underwater work of ocean.

• Journal of the Korea Concrete Institute
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• v.12 no.6
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• pp.91-98
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• 2000

Porous concrete having continuous voids is gaining more interest as an ecological material. It has several useful functions such as water and air permeability, sound absorption, etc. Its strengths are considerably lower than those of conventional concrete due to the large and continuous voids in it. This study has been carried out to investigate the influence of mix factors and mixture proportion of aggregate on the strengths and water permeability of porous concrete. And it has been carried out to investigate the evaluation of void of porous concrete by the ultra-sonic pulse velocity. The results f this study are as follows: 1) The theoretical void ratio has greater influence than any other factor on the strengths and water permeability of porous concrete. And it is a little affected by the replacement proportion of silica-fume and mixture proportion of aggregate. 2) Because the coefficients of correlation between the void ratio and ultra-sonic pulse velocity were relatively high, it will be possible that the void ratio is predicted by the ultra-sonic pulse velocity.

• Journal of the Korean Society of Costume
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• v.50 no.8
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• pp.29-41
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• 2000

This study was intended to grasp the actual condition of adult women's wearing foundation garments for the Korean adult women in their 20s to 40s. For this purpose, questionnaire research was conducted for 639 adult women in their 20s to 40s living in Seoul and Kyonggi Province. As for the reason for the purchase of foundation garments, It was found that the highest proportion of the responding adult women would buy brassieres when they were needed because the old ones were threadbare, followed by the purchase of brassiere when they caught their eyes in shopping around. As for the reason for the purchase of girdles, the highest proportion of the responding adult women could buy girdles when they were needed because their old ones were wornout, and next when bargain sale began at the department store or the large shopping center. The highest proportion of the responding adult women thought the source of information on foundation garments as the window display, followed by magazine. The adult women in their 30s collected information on foundation garments through the window display when buying brassieres or girdles. As for the product evaluation criteria of foundation garments, the highest proportion of the responding adult women thought highly of the feeling of wear in brassieres and girdles, followed by dimensions in brassieres and bodily correctability in girdles. As for the place of buying brassieres or girdles, the responding adult women showed it to be the department store. followed by the discount store and the well-known agency.

• Journal of the Korean Wood Science and Technology
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• v.26 no.1
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• pp.63-69
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• 1998

This study was carried out to get some basic information on mechanical properties of Korea Lepidobalanus for rational utilization of wood. Five species of Quercus variabilis, Q. aliena, Q. serrata, Q. mongolica, Q. acutissima belong to Lepidobalanus were investigated in this research. Relationship of anatomical characteristics to compression strength parallel to grain was analyzed using stepwise regression technique. All possible combination of 21 independent variables were regressed on compression strength parallel to grain. The summarized results in this study were as follows: I. In the proportion of wood structural elements, the factors that had the greatest influence on compression strength parallel to grain appeared to be proportion of ray in earlywood in Q. variabilis and Q. acutissima, proportion of wood fiber in latewood in Q. aliena and Q. serrata and proportion of vessel in earlywood in Q. mongolica respectively. 2. In the size of wood element and its structure, the factors that had the greatest influence on compression strength parallel to grain were microfibril angle in Q. variabilis, Q. serrata and Q. mongolica and length of wood fiber in Q. aliena and Q. acutissima.

• Journal of The Korean Society of Grassland and Forage Science
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• v.10 no.1
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• pp.36-41
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• 1990

The more N fertilizer, the more grass proportion (58 8, 240 kg N/ha) and the less white clover (Trifolium repens) (6 %, 240 kg N) under grazing utilization. The proportion of white clover was maintained about 27 % at 60 kg N/ha/yr and weed proportion was reached 33 %. Under the condition of differentiated N rates, the proportion of white clover was ranged from 10 to 36 % at 20 kg N/ha/cut which was allocated after every grazing and it probably dependent on differentiated N rates rather than total amounts of N applied annually. 53-74 % of total dry matter yield were concentrated at 1st and 2nd growth under grazing system and there were no great differences in dry matter yield at 3rd, 4th, and 5th growth in comparison with the variations of N rates. There was very significant relationship between the proportions of white clover and the amounts of N uptaken by herbage upto 180 kg N/ha. About 138 kg N/ha were uptaken by herbage without N fertilizer but only with white clover (31 %) as a substitute of N. In the amounts of crude fiber and crude protein by differentiation of N fertilizer, there were no any great variations and liveweightgain during grazing periods was reached 1583 kg liveweightlha.

• Education of Primary School Mathematics
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• v.12 no.2
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• pp.117-132
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• 2009

The purpose of this study was analysis on types of strategies and errors when the sixth grade students were solving proportion problems of mathematics textbooks. For this study, proportion problems in mathematics textbooks were investigated and 17 representative problems were chosen. The 277 students of two elementary schools solved the problems. The types of strategies and errors in solving proportion problems were analyzed. The result of this study were as follows; The percentage of correct answers is high if the problems could be solved by proportional expression and the expression is in constant rate. But the percentage of correct answers is low, if the problems were expressed with non-constant rate.

• Journal of Environmental Science International
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• v.13 no.12
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• pp.1103-1108
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• 2004

This experiment was carried out to investigate the effects of cadmium on the growth of Arabidopsis thaliana when they were treated with different concentrations of cadmium. The growth of stem was stimulated in the concentrations up to fifty times higher than the official standard concentration of cadmium of pollutant exhaust notified by the Ministry of Environment, but it decreased in the concentration one hundred fifty times or more higher in proportion to the degree of concentration. The growth of root was similar to that of stem, except that the decrease was gradual in the concentration fifty times or more higher. The growth of leaf was almost the same as that of stem, that is, it was stimulated the increase of leaf surface area in the concentration fifty times higher, but decreased in the concentration one hundred fifty times or more higher in proportion to the degree of concentration. The fresh weights of the plants were increased in accord with the degree of growth of the stem and leaf. Concentration of cadmium accumulated in the plants was increased in proportion to the concentration of cadmium. These results show that the growth of plants was stimulated in the soil polluted by cadmium up to fifty times higher than the official standard concentration, but it was decreased in proportion to the degree of concentration in the plants grown in the presence of cadmium more than one hundred fifty times.

• Journal of Engineering Education Research
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• v.24 no.4
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• pp.61-74
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• 2021

The purpose of this study is to provide a direction for domestic engineering education research by analyzing the research trends of JEE(Journal of Engineering Education). The results of analyzing research trends regarding research topics, research objects and research methods are as follows. First, by research topic, 'Diffusion of Educational Innovation' was found to have the highest proportion with 52 articles(21%). Second, by research objects, 'university students' showed the highest proportion with 148 articles(53.6%). Third, by research method (large category), 'quantitative research' had the highest proportion with 132 articles(53.2%). By research method (medium category), 'survey research' had the highest proportion with 129 articles(33.5%). Based on the results of this study, future engineering education research should be conducted to contribute to holistic development through diversification of research topics, methods, and objects.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.2
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• pp.635-641
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• 2021

This article analyzes the factors affecting income inequality in Vietnam, with data from 63 provinces and cities collected from the Vietnam Household Living Standards Survey of the General Statistics Office of Vietnam from 2010 to 2018. The article will firstly build a research model to identify factors affecting income inequality. Then, it uses the Generalized Method of Moments (GMM) method to evaluate the effect of factors on income inequality in Vietnam. The empirical estimate result shows that, in the period from 2010 to 2018, the factors such as the proportion of the working employees, income per capita, and inflation have positive effects on the Gini coefficient. That is, when these factors increase, there will be negative effects on improving income inequality in Vietnam. Conversely, when the factors such as the proportion of the literate adults, the proportion of the urban population, and population density increase they will have a positive impact on improving income inequality in Vietnam during this period. The estimated coefficients satisfied the sign expectation except the proportion of the literate adults. It means that, in Vietnam, the increase and more equilibrium in educational attainment balance the distribution of income and bring an improvement in income inequality.

• Health Policy and Management
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• v.32 no.1
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• pp.107-112
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• 2022

Catastrophic healthcare expenditure refers to out-of-pocket spending for healthcare exceeding a certain proportion of a household's income and can lead to subsequent impoverishment. The aim of this study was to investigate the proportion of South Korean households that experienced catastrophic healthcare expenditure between 2006 and 2020 using available data from the National Survey of Tax and Benefit (NaSTaB), Korea Health Panel (KHP), and Households Income and Expenditure Survey (HIES). Trend test was used to analyze the proportion of household with catastrophic healthcare expenditure. In the NaSTaB 2020 data, households who experienced catastrophic health expenditure was 1.73%. Trend analysis was significant with the decreasing trend (annual percentage change [APC], -5.55; p<0.0001) in the proportion of households with the catastrophic health expenditure. Also, in the 2018 KHP and the 2016 HIES, households who experienced catastrophic health expenditure was 2.21% and 2.92% respectively. In contrast, the trend was significantly increased in the KHP (APC, 0.55; p<0.0001) and the HIES (APC, 1.43; p<0.0001). Therefore, the findings suggest the need to strengthen public health care financial support and monitor catastrophic healthcare expenditures, especially for low-income group.