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An Experimental Study on the Mix Proportion in Fluidity and Engineering Properties of High Flowing Concrete (고유동콘크리트의 유동특성 및 공학적특성에 미치는 조합요인에 관한 실험적 연구)

  • 신홍철;우영제;강석표;김규용;정하선;이석홍;손영현;김무한
    • Proceedings of the Korea Concrete Institute Conference
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    • 1998.10a
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    • pp.307-312
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    • 1998
  • Recently the study on high flowing concrete which has high workability and Self-compacting is being proceeded actively in the university and corporative laboratory. There are some cases that has been applied to the field. This high flowing concrete has higher fluidity and segregation resistance than Plain of flowing concrete. And it is being focused as a remarkable know-how which can make high-quality concrete and reduction effect of labor force. This properties of high flowing concrete are influenced by the relationship of several factors; binder content, water binder ratio and unit water content. It is the aim of this study to propose reference data at mix design of high flowing concrete, after comparing and analyzing the fluidity and strength properties of high flowing concrete according to water binder content ratio and unit water content.

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An Experimental Study on the Frost Resistance of High-Flowing Concrete Using Granulated Blast-Furnace Slag (고로슬래그 미분말을 사용한 고유동콘크리트의 내동해성에 관한 실험적 연구)

  • 김무한;권영진;강석표
    • Journal of the Korea Concrete Institute
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    • v.12 no.2
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    • pp.43-51
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    • 2000
  • This study is to investigate for the frost resistance of high-flowing concrete using finely ground granulated blast-furnace slag with experimental parameters, such as type of binder, type of superplasticizer and method of curing. The resistance to freezing and thawing of high-flowing concrete by type of binder and superplasticizer is presented differently. Though the frost resistance of high-flowing concrete is satisfactory under standard condition, it is required that high-flowing concrete has entrained air like plain concrete. Because the critical spacing factor, being capacity of frost resistance, of high-flowing concrete is longer that of plain concrete, the frost resistance of high-flowing concrete, using finely ground granulated furnace blast slag, is superior to that of plain concrete.

A Study on the Level of Perception to Internet Shopping′ Benefit - Risk in Relation to the Internet Searching Value Types of College Student Consumers (대학생소비자의 인터넷탐색가치유형과 인터넷쇼핑에 대한 혜택-위험 지각정도에 관한 연구)

  • 홍은실
    • Journal of the Korean Home Economics Association
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    • v.40 no.2
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    • pp.161-173
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    • 2002
  • This study explored the Internet searching values(utilitarian searching value and hedonic searching value) of college student consumers, typed the Internet searching values to four types, and analysed the level of perception to Internet shopping' benefit-risk according to the Internet searching value types. The subjects were 361 college students. We used Cronbach'$\alpha$, multiple regression, one-way ANOVA, and Scheffe' test as statistical analysis. The results were summarized as follows : 1) According to the Internet searching values, college student consumers were classified into 4 types - high utilitarian/high hedonic type, high utilitarian/low hedonic type, low utilitarian/high hedonic type, and low utilitarian/low hedonic type. 2) Both high utilitarian/high hedonic type and low utilitarian/high hedonic type had high level of perception to Internet shopping' benefit-risk.

서울시 고교에서의 특수재능교육

  • 조석희
    • Journal of Gifted/Talented Education
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    • v.7 no.2
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    • pp.47-67
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    • 1997
  • Fourteen Special high schools for developing talents in Science, Foreign Languages, and Arts in Seoul Metropolitan city were analyzed in terms of their educational objectives, Students screening system, curriculum, teaching-learning methods, teachers, and consistency with higher education. Special high schools in talent area were more or less similar to each other in all the above aspects. However, special high schools in different talent areas were quite different in student screening, teaching-learning methods, teachers, and consistency with higher education. Public schools were more affluent than the private ones. Special high schools in Science, arts and Sports were providing individualized, activity oriented, process-oriented teaching-learning methods, while the Foreign languages high schools excercised teacher-centered, grammar oriented, lecture-focused teaching methods more. Special high schools in arts and sports could have consistency with higher education because the university focuses on talents in the specified field rather than academic scores. In conclusion, the schools have a great deal of rooms to improve in teaching-learning methods with which students can maximize their potential development. However, the special high schools were equipped with better learning environments than regular high schools in many aspects.

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High Glucose Inhibitory Effects on Bone Formation in UMR106 Cells

  • Kwon, Eun-Hee;Jung, In-Ok;Kim, Sung-Jin
    • Biomolecules & Therapeutics
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    • v.11 no.2
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    • pp.81-84
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    • 2003
  • Recently, diabetes has been found to be associated with osteoporosis. Specially in IDDM. In both type I and type II diabetes, glucose levels are elevated. Thus, a linkage between high glucose and osteoporosis can not be ruled out. In this study, an attempt has been made to observe the effect of high glucose on bone formation; osteoblast like UMR 106 cells were treated with high glucose (22 mM, 33 mM) for 1, 3 or 7 days. The high concentration of glucose inhibited markers. of bone formation activity such as alkaline phosphatase and collagen synthesis. In addition, reduction in the level of total cellular protein in response to high glucose was also observed. This study showed high glucose concentration could alter the bone metabolism leading to a defective bone formation and thus paving the linkage of such situation to diabetic complications.

A Study on the High-Speed Railway Safety Evaluation using the F-AHP

  • Park, Tae-Keun;Park, Choon-Soo;Seo, Seung-Il
    • Proceedings of the Korean Operations and Management Science Society Conference
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    • 2004.05a
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    • pp.581-585
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    • 2004
  • The purpose of this study is to suggest a method to support decision making of researchers, when we estimate the safety of the high-speed railway using F-AHP. To apply this method, Korean type of high-speed railway was engaged, and the 8 Stages of accident type and the five criteria were suggested that we must meet. Then, the interview with the researchers working for high-speed railway was used to confirm the alternatives suggested. The employed F-AHP for this study estimate using emotional words based on AHP of Saaty, so it is very good to estimate the high-speed railway safety.

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The investigation of postural balance recovery mechanism of high-heeled women using COP's kinematic characteristics during the waist pulling (전방향 동요 시 압력중심의 기구학적 특성을 통한 하이힐 착용 여성의 자세균형회복 메커니즘에 관한 고찰)

  • 조원학;서민좌;최현기
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2004.10a
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    • pp.1211-1214
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    • 2004
  • High-heeled women have been identified with balance control problems. The purposes of this study were to objectively quantify the displacements and velocities of center-of-pressure (COP) of body during waist pulling and to compare the differences between barefooted and high-heeled situations. We used a waist pulling system which has three different magnitudes to sway the subjects. We found that the kinematic information of barefooted and high-heeled women's COP is very important in understanding the mechanism of postural balance control of women in every-day life. In the high-heeled's case, the displacement of COP increases in 200% as against bare footed. Also the velocity variation of COP grows three times than the bare footed. COP analysis in postural balance study of high-heeled women is also considered useful in development of the safety systems that prevent high-heeled women from falling

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Genetic Algorithm in Mix Proportioning of High -Performance Concrete (고성능 콘크리트 배합 설계에서의 유전자 알고리즘의 적용)

  • 임철현;윤영수;이승훈;손유신
    • Proceedings of the Korea Concrete Institute Conference
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    • 2002.05a
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    • pp.551-556
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    • 2002
  • High-performance concrete is defined as concrete that meets special combinations of performance and uniformity requirements that cannot always be achieved routinely using conventional constituents and normal mixing, placing, and curing practices. Ever since the term high-performance concrete was introduced into the industry, it had widely used in large-scale concrete construction that demands high-strength, high-flowability, and high-durability. To obtain such performances that cannot be obtained from conventional concrete and by the current method, a large number of trial mixes are required to select the desired combination of materials that meets special performance. In this paper, therefore, using genetic algorithm which is a global optimization technique modeled on biological evolutionary process-natural selection and natural genetics-and can be used to find a near optimal solution to a problem that may have many solutions, the new design method for high-performance concrete mixtures is suggested to reduce the number of trial mixtures with desired properties in the field test. Experimental and analytic investigations were carried out to develop the design method for high-performance concrete mixtures and to verify the proposed mix design.

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On the Research and Development for High Level Radioactive Waste Disposal in Korea (고준위 방사성폐기물 처분 기술개발 현황)

  • Lee, Young-Up
    • Economic and Environmental Geology
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    • v.28 no.3
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    • pp.279-286
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    • 1995
  • The amount of the high level radioactive wastes in Korea will be increased up to 14,297 MTU about 2010 year. Most of countries adopt the concept of deep burial repository in high level radioactive waste disposal. Because the high level radioactive wastes are very toxic in biosphere and to human, the data verifing its never return to the biosphere are requisite for the disposal. Presently, the evaluating techniques for the high level radioactive waste disposal are not fully developed. Therefore, in order to dispose the high level radioactive wastes in proper time the R & D of it is urged in our country. The R & D and/or the international joint research programme for the disposal of high level wastes have already been proceeded. In our country no plan for its disposal has been prepared. It is the time that the direction of the R & D is to be discused seriously. The R & D for the disposal of high level radioactive wastes in Korea is believed to be focused on developing the pecular techniques such as in situ characteristics of groundwater flowage, and change of properties of in situ rock mass at thermal effects.

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Comparison of Intake , Digestibility , and Utilization of Nitrogen by Gcats Consuming High and Low Tannin Forage Sources (탄닌함량이 높고 낮은 사초류를 급여했을 때 산양에 의한 섭취량 , 소화율 및 질소이용성 비교 연구)

  • 이인덕;이형석;이중해
    • Journal of The Korean Society of Grassland and Forage Science
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    • v.16 no.3
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    • pp.230-234
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    • 1996
  • This study was conducted to compare the intake, digestibility and utilization of nitrogen by goats consuming high and low tannin diets. Low tannin diets were 100% grass(GS) and 50% grass + SO% alfalfa (GA), and high tannin diets were 50% grass + 50% lespedeza(GL) and 50% grass + 50% oak browse(G0). Dry matter intake did not differ among all diets, but digestibility of dry matter, cellular constituents, NDF and ADF showed slightly lower for high tannin diets(GO) than low tannin diets(GS and GA), but those were not differ between GL and low tannin diets with the exception of ADF digestibility. Total faces and urinary N were lower for high tannin diets than for low tannin diets. Apparently digested N was high in GA diets, but low in GO diets(P

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