• 콘크리트학회논문집
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• 제16권6호
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• pp.795-803
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• 2004

현행 구조설계기준식에서는 취성적으로 파괴하는 최소전단보강철근 파괴를 방지하기 위하여 철근콘크리트 보에 최소전단보강철근을 배근하도록 규정하고 있다. 최소전단철근비는 콘크리트의 압축강도와 함께 주인장철근비와 전단경간비에 영향을 받는다. 이 연구에서는 주인장철근비와 전단경간비가 철근콘크리트 보의 최소전단철근비에 미치는 영향을 파악하기 위하여 14개의 철근콘크리트 보를 실험하였다. 실험에 의하면 전단 여유율은 주인장철근비가 증가할수록 증가하였고, 전단경간비가 증가할수록 감소하였다. 실험 결과는 ACI 318-02 기준식과 선행 연구의 제안식과 비교되었다.

• 대한가정학회지
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• 제12권2호
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• pp.621-631
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• 1974

The objective of the study was to obtain standard sizes of body of the high school girls for designing clothes and developing pattern grading of clothes. In 1972, 342 students, selected by the stratified cluster random sampling method, at three high schools in Seoul were measured on forty-one items by the R. Martin method. Statistical techniques of mean, standard deviation, coefficient variable, maximum and minimum, range, t-test were utilized to analyze the data. The findings of the study were as follows ; 1. No differences were found among the age groups in the all measured variables. 2. Stature, bust girth, hip girth, acromion width, posterior waist girth/stature ratio of the high school girls were significantly smaller than those sizes of adult women. This result implies that those sizes will be increased as the students grow up. But upper arm girth, upper arm girth/bust girth ratio, and thigh girth/bust girth ratio were bigger than those sizes of adult women. Waist girth, thigh girth, total head height/stature ratio, acromion width/stature ratio, and foot length/stature ratio were nearly similiar to those of adult women. 3. According to the result of t-test, waist breadth, spinailiaca anterior height/stature ratio, thigh girth/bust girth ratio, and thigh/hip girth ratio of the 15 year old group were significantly different from those of the 16 year old group at the level of 0.05. Bust girth, weight, foot breadth, posterior croth length, and cervical height/stature ratio of the 16 year old group were significantly different from those of the 17 year old group at the level of 0.01. Hip girth, upper arm girth, waist breadth/stature ratio, and neck base girth/bust girth ratio of the 16 year old group were significantly different from those of the 17 year old group at the level of 0.05.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 추계학술대회 논문집
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• pp.431-434
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• 2009

Conceptual study of an open-circuit type low-speed wind tunnel for test of wind turbine blade is conducted. The tunnel is constituted of a settling chamber, a contraction, closed and open test sections, a diffuser, two corners, a cross leg and a fan and motor. For the performance test, the closed test section width of 1.8 m, height of 1.8 m and length of 5.25 m is selected. The open test section with dimension width of 1.8 m, height of 1.8 m and length of 4.14 m is adopted for aeroacoustic test. The contraction ratio is 9 to 1 and maximum speed in the closed test section is 67 m/sec. Input power in the tunnel is about 238 kW and its energy ratio is 3.6. The wind tunnel designed in present study will be an effective tool in research and development of wind turbine.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 춘계학술대회 논문집
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• pp.393-399
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• 2003

This paper describes a proper criterion for the constant rate of loading consolidation (CRLC) test which is a kind of the continuous loading consolidation(CRLS) and widely used as alternative methods to the incremental loading consolidation(ILC)test. With those results, the preconsolidation pressure estimated by the CRLC test turned out to be comparatively larger than that of the ILC test and it is increased in proportion to the applied loading rates. However, the compression index in the CRLC test is less ifluenced on by the loading rates. The coeffcient of consolidation and permeability in the CRLC test are dependent on excess pore pressure ratio mainly. In other words, if the pore pressure ratios are too low, the coefficient of consolidation and permeability become smaller than those of the ILC test. On the other hand, if the excess pore pressure ratios are too high, the coefficient of consolidation and permeability become so larger than those of the ILC test. Therefore loading rates should be carefully determined to generate proper excess pore pressure ratio.

• Nuclear Engineering and Technology
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• 제54권3호
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• pp.1071-1084
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• 2022

The present study aims to investigate the dynamic properties of a novel isolation system composed of separate rubber and wire isolators. The testing program comprised pure compressive, pure-shear, compressive-stress dependence, and shear-strain dependence tests that used full-scale test specimens according to ISO 22762-1. A total of 22 test specimens were fabricated and investigated. Among the tests, the pure compressive test was a destructive test that reached up to the failure stage, whereas the others were nondestructive tests before the failure stage. Similar to the pure-shear test, at each compressive-stress level in the compressive dependence test or at each shear-strain level in the shear-strain dependence test, the cyclic loading was conducted for three cycles. In the nondestructive tests, examination of the dynamic shear properties in the X-direction was independent of the Y-direction. The test results revealed that the increase in the shear strain increased the energy dissipation but decreased the damping ratio, whereas the increase in the compressive stress increased the damping ratio. In addition, a macro model was developed to simulate the load-displacement response of the isolation systems, and the prediction results were consistent with the experimental results.

• 한국연소학회지
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• 제21권4호
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• pp.16-22
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• 2016

Pressure and temperature variations in a shock tube have been studied numerically by changing the diameter ratio of a driven part to a driver part. There are five cases where the adopted diameter ratios are 40%, 50%, 60%, 80%, and 100% respectively. The diameter of the driver part remains unchanged meanwhile the shock tube driven part diameter increases from 40% to 100% of the driver part. In the 100% ratio case, the driver part and driven parts have the same diameter of 66.9 mm. As the diameter ratio decreases, the pressure in the shock tube and available test time are increased.

• 한국동물위생학회지
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• 제19권3호
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• pp.221-226
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• 1996

IBD's antibody level and morphological change of immune organ was examined in chicken. The results were as follows ; 1. Seventy percent at 42 day and 40% at 45 day of age chickens were reacted positively by the agar gel immunodiffusion test and 42 day and 45 day of age chickens indicated 1859, 1425 by the ELISA test, respectively. 2. In 2 and 5 day young broiler chickens, the level of maternal antibody was not proper. B/B ratio showed low level, but S/B ratio and BS were normal. 3. In layer, 100% of 8 and 86 day of age chicken and 70% at 40 day of age chicken had antibody aganist IBDV. The level of antibody was high as 2293 and 3336 in 8 and 86 day of age chicken, while was low as 1186 in 40 day of age chicken. B/B ratio showed low level and S/B ratio high level, but BS was normal.

• 한국산업융합학회 논문집
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• 제10권4호
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• pp.255-262
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• 2007

The main purpose of this study is to figure out of seismic structural behaviour of Gukrakjeon of Bongjung-Temple which is the oldest wooden architecture in Korea, and to evaluate in engineering aspect of seismic records. The non-lineal analysis is essential for accurate evaluation of wooden architecture in seismic behaviour. Based on the experimental test with applying cycle forces in joint specimens is focusing on not only to prove the structural characteristics, but also to evaluate damping ratio, As the result of this test, damping ratio is affected not the joint methods but the frame variations. The average damping ratio was 26%.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 가을 학술발표회논문집(I)
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• pp.751-756
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• 2000

The dynamic characteristics such as natural frequency, mode shape and damping ratio are most important parameters in the high-speed railway bridges rather than general roadway bridges. Also, the need to know the dynamic behavior of bridges greatly increased in recent years. In the early of 1990s, to design the high-speed railway bridges, damping ratio recommended in general code was 2.5~7.5%. However, these values were not applied in all cases. Therefore, obtaining the damping value of specific structures is important to get the correct variable for design of high-speed railway bridges. The purpose of this study is mainly to obtain the damping ratio of high-speed railway bridges. The average damping ratio of high-speed railway bridges evaluated from a field test is about 2.4%.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2003년도 가을 학술발표회 논문집
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• pp.23-26
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• 2003

Metakaolin is a cementitious material for producing high-strength concrete. This material is now used as substitute for silica-fume. In this paper, we studied the properties of fresh concrete such as slump-flow, air content, and the feature of strength of hardened concrete according to the substitute ratio of metakaolin, silica-fume. In the fresh concrete test, the time depend loss of slump-flow & air content is good to 10-15% substitute ratio of metakaolin. And, in the strength test, 10-15% substitute ratio of metakaolin is good for producing high-strength concrete also. But, allowing for economical efficiency, we concluded that 10% is a adequate substitute ratio for producing high performance concrete.