• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2000.10a
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• pp.407-414
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• 2000

The friction pendulum type seismic isolation system (FPS) has been developed to provide a simple and effective way to achieve earthquake resistance for buildings . The major advantages are: the isolation frequency can be easily achieved by designing a curvature of the surface and does not depend on the supported weight of a structure. The function of carrying vertical load is separated to the function of providing horizontal stiffness. Next the friction provides sufficient energy dissipation to protect the structure from earthquake response and resistance to the weak external disturbances such as wind load and ground vibrations due to traffic. In this paper, the friction coefficients are evaluated from number of experiments on the FPS test specimens. The relations between friction coefficient and the test waveform, velocity, and pressure are reviewed and further works are discussed.

• ETRI Journal
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• v.30 no.6
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• pp.844-849
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• 2008

A new transcutaneous energy transmission (TET) system was developed for transmitting electrical power to an implanted device, such as an artificial heart in a patient's body. This new design can maintain a stable output voltage independent of the load resistance. The system includes a compensation capacitor to reduce energy loss and increase power transfer efficiency. Experimental results show that the output voltage of the receiving coil changes very little as the load resistance varies from 14.8 ${\Omega}$ to 15 $k{\Omega}$, which corresponds to a change in output power from 0.1 to 97 W.

• Transactions of the Korean Society of Mechanical Engineers
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• v.6 no.2
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• pp.101-106
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• 1982

This study was undertaken to determine tensile properties and low-cycle fatigue behavior of 0.6%C high carbon steel used of structural purposes at temperatures up to 500.deg.C. In the low-cycle fatigue test the upper limit was decided by elongation(i.e. the total strain range), while the lower limit was defined by the load (i.e. zero load). The following results were obtained. Both, the ultimate tensile strength and low-cycle fatigue resistance attain the maximum values near 250.deg.C. Above this temperature the values decrease rapidly as the temperature increases. The low-cycle fatigue resistance decreases whenever there is an increase of the total strain range. Because the hardness of cycle fatigued specimen correlates cyclic hardening and cyclic softening, therefore the hardness of cycle fatigued specimen is smaller than that of the nonfatigued specimen at room temperature and 500.deg.C but much larger than the hardness of the nonfatigued specimen near 250.deg.C.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.11 no.4
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• pp.6-11
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• 2002

Formability in deep drawing process depends not only on a drawability of workpiece material but also on process conditions such as die punch comer radius, lubricant conditions, punch-die clearance etc. For instance, bending resistance should be reduced by increasing die round appropriately, drawing load should be minimized by improving the lubricant condition between die and material, and blanking load should be increased by selecting a pertinent punch round and by augmenting the friction resistance in punch. In this study, a multi-stage deep drawing process is analyzed using ABAQUS. The effects of formability factors, such as die shoulder radius, punch-die clearance and friction coefficient are investigated, and the results are also discussed in detail.

• Magazine of the Korea Concrete Institute
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• v.4 no.4
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• pp.123-133
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• 1992

확률이론을 이용한 구조물 신뢰성에 관한 연구가 최근 급속히 발달함과 동시에 구조물의 저하능력과 작용하중들의 확률적 특성들에 대한 인식이 제고됨에 따라 여러나라에서 확률이론에 근거한 설계규준이 개발되고 있다. 작용하중이나 구조저항력의 확률적 특성을 보이고 있기 때문에 외국의 설계규준을 직접 도입하는 것은 여러 가지 문제점이 있으며, 따라서 국내현실에 적합한 설계규준에 대한 연구가 필요하다. 본 연구에서는 국내 철근콘크리트 구조물의 합리적인 설계규준을 제시하기 위하여 국내에서 수집\ulcorner분석된 구조부재강도 및 작용하중의 확률적 모형을 이용하여 현행 설계규준에 내포된 신뢰도를 검정하고 나아가 최적하중계수를 분석하였다.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.66 no.4
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• pp.219-223
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• 2017

In this paper, we calculated the losses in the high voltage lines of power distribution system. The losses caused by high voltage lines are calculated using maximum current, resistance, loss factor, and dispersion loss factor. The accurate extraction of these factors are very important to calculate the losses exactly. Thus, the maximum loads are subdivided to regions and calculated monthly for more accurate maximum current calculation. Also, the composite resistance is calculated according to the ratio of the used wire types. In order to calculate the loss factor, the load factors according to the characteristics of each region were calculated. Finally, the losses of the distribution system is calculated by adding the losses by the transformers and the low voltage lines.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2001.10a
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• pp.280-285
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• 2001

A good drawability of material itself is required. To improve the formability in deep drawing process. Besides that bending resistance should be reduced by increasing die round appropriately, drawing load should be minimized by improving the lubricant condition between die and material, and breaking load should be increased by selecting a pertinent punch round and by augmenting the friction resistance in Punch. In this study, a multi-stage deep drawing process is analyzed using ABAQUS, the effects of formability factors. Such as die shoulder radius, punch-die clearance and friction coefficient are investigated.

• Textile Coloration and Finishing
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• v.1 no.1
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• pp.35-46
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• 1989

Experiments described in which cotton fabrics at different stages of chemical processing were abraded to different extents on a Stoll Abrasion Tester with three different abradants, namely, a worsted fabric, flax fabric and silicon carbide paper. The four different plain-weave cotton fabrics selected were 1) desized, 2) scoured and bleached, 3) mercerized, 4) resin-treated. The surface abrasive damages of treated fabrics were observed by SAM, and load-elongation percent retentions of abraded samples were measured by Instrong Tester. The result were as follows: 1. The maximum percent retention of load-elongation with three different abradants was exhibited by the scoured and bleached fabrics and the minimum by the resin finished fabric. 2. The electron micrographs of four different cotton fabrics abraded by flax, worsted fabric abradants for 900 rubs showed a large number of criss-crossing stray fibers in fabric structure. It may be the molecular adhesion for frictional resistance to be explained. 3. The electron micrographs of four different cotton fabrics abraded by silicone carbide abradants showed the form of busing or mashing fibers in fabric structure. The above might be on the basis of the ploughing theory.

• Journal of the Korean Society of Safety
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• v.13 no.2
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• pp.3-12
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• 1998

Polymer materials have been used offensively as construction materials for automobiles, ships, and airplanes in recent years, and their impact resistance has been obliged to be examined. In the present study, a dropped load and a specimen, equipped with high responsible strain gauges respectively, were dropped and then the changes of load and absorption energy with time were observed. It was found that the waveforms for dropped weight coincided with output signal wave for specimen during the destruction test. Based on this experimental result, three disc type of specimens with different compositions were prepared and examined. This instrumented impact test method showed that each specimen can be distinguished from each other better than conventional tests and is expected to contribute to assess test results of impact resistance for some materials under development.

• Steel and Composite Structures
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• v.28 no.4
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• pp.449-460
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• 2018

This paper reports the experimental results of three through bolt beam-column connections under pure shear forces using modified push-out tests. The investigated specimens include extended end-plates and six through-bolts connecting square concrete-filled steel tubular column (S-CFST) to steel beams. The main goal of this study is to investigate if and how the mechanical shear connectors, such as steel angles and stud bolts, contribute to the shear transfer mechanisms in the steel-concrete interface of the composite column. The contribution of shear studs and steel angles to improve the shear resistance of steel-concrete interface in through-bolt connections was investigated using tests. The results showed that their contribution is not significant when the beam-column connection is included in the push-out tests. The specimens failed by pure shear of the long bolts, and the ultimate load can be predicted using the shear resistance of the bolts under shear forces. The predicted values of load allowed obtaining a good agreement with the tests results.