• Title/Summary/Keyword: Physical Experiments

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Effect of False Twist Processing Conditions on the Physical Properties of PET DTY (PET 가연공정특성이 DTY의 물성에 미치는 영향)

  • 이민수;김승진;박경순
    • Textile Coloration and Finishing
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    • v.15 no.6
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    • pp.33-38
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    • 2003
  • This study surveys the effects of POY physical properties and processing conditions of belt texturing machine to the textured yarns. The various textured yarns are made with the variations of 1st heater temperature, draw ratio, velocity ratio, and the physical properties of these specimens such as yam linear density, tenacity, breaking strain, and wet and dry thermal shrinkages are measured and analysed with the various processing conditions of texturing machine. Especially, the thermal characteristics of the textured yarns, which are affected at the fabric hands and the determination of the processing conditions in the dyeing and finishing processes, are investigated through the thermal stress analyser and DSC experiments.

On the Physical Meaning of Maxwell Stress Tensor (맥스웰 응력텐서의 물리적 의미의 고찰)

  • Choi, Hong-Soon;Park, Il-Han;Moon, Won-Kyu
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.58 no.4
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    • pp.725-734
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    • 2009
  • Maxwell stress tensor is one of the methods which are generally used for electromagnetic force calculation. In this paper, it is presented that Maxwell stress tensor T and n${\cdot}$T have no physical meaning and therefore should not be used as sources of mechanical force for deformations or dynamics. The divergence of Maxwell stress tensor ${\nabla}{\cdot}T$ is the one which can acquire a physical identity and is electromagnetic body force density by an action at a distance like a gravity. This result can be derived from the principle of power balance, and also verified by some thought experiments. The virtual air-gap approach is proposed as a valid solution for the calculation of the body force.

A Feasibility Study on a Robotic Exercise System for MDOF Physical Rehabilitation Therapy

  • Sim, Hyung Joon;Won, Joo Yeon;Han, Chang Soo
    • Journal of Mechanical Science and Technology
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    • v.18 no.11
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    • pp.1949-1960
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    • 2004
  • This paper presents a robot system developed for medical purpose. A 6-degree-of-freedom robot was introduced for physical exercise and rehabilitation. This system was proposed for stroke patients or patients who cannot use one of their arms or legs. The robot system exercises the hemiplegic part based on the motion of normal part of a patient. Kinematic studies on the human body and robot were applied to develop the robotic rehabilitation exercise system. A clamp which acts as an end effector of the robot to hold a patient was designed and applied to the robot to guarantee the safety of patients. The proposed robotic rehabilitation system was verified by simulations and experiments on arm (elbow and shoulder) motion. Patients are expected to be able to exercise various motions by themselves with the proposed robotic rehabilitation system.

An Experimental Study on the physical-mechanical Properties of Ultra-High-Strength-Concrete (초고강도 콘크리트의 물리적·역학적 특성에 관한 실험적 연구)

  • Park, Hee-Gon;Lee, Jin-Woo;Bae, Yeoun-Ki;Kim, Woo-Jae;Lee, Jae-Sam;Jung, Sang-Jin
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2008.11a
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    • pp.107-111
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    • 2008
  • As high-rise buildings with 100 or more stories are being constructed, it is inevitable to use high-performance materials including high-performance concrete. What is most important in high-performance concrete is extremely high strength in order to reduce the section of members in high-rise buildings. During the last several years, there have been active researches on Ultra-high-strength concrete. While these researches have been mostly focused on strength development, however, other accompanying physical properties have not been studied sufficiently. Thus, this study purposed to obtain and analyze data on the physical-mechanical properties of Ultra-high-strength concrete through experiments and to use the results as basic information on required performance of concrete used in high-rise buildings.

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A Study on the Physical Properties of MgO Board for Wall System (경량 벽체용 MgO 보드의 물리적 특성에 관한 실험적 연구)

  • Kim, Soon-Ho;Kim, Hong-Yong
    • KIEAE Journal
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    • v.7 no.4
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    • pp.135-140
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    • 2007
  • In this study we settled the trouble of the MgO board of existence by this research. We changed the wooden one of the main ingredient of a board to a perlite and a mineral particle in the aluminum hydroxide group and proceeded with a study to physical character and fire resistance efficiency improvement. The result yellowing phenomenon could be improved and it was possible to reduce size decrease of pin hole and the frequency of occurrence. We found out that the in case of absorbed amount added 5~8% corresponding to the weight decreases the acrylic group emulsion suddenly. So this product is improved with the bending strength and water-resistance. After behavior stop time measurement of a mouse for experiments was measured at the time of a gas harmful effect test, an improved MgO board appeared more highly for an average of 138 seconds compared with a board of existence.

An Experimental study on durability improvement of concrete structures by a concrete coating method (도포공법에 의한 콘크리트 구조물의 내구성 증진에 관한 실험적 연구)

  • 조병완;문린곤;박승국;김대민
    • Proceedings of the Korea Concrete Institute Conference
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    • 2003.05a
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    • pp.721-726
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    • 2003
  • The Durability of Concrete Structure is serverely degraded due to mainly carbonation, sulfate attack and chloride ion diffusion in concrete. The ultimate purpose of this study is to obtain how much the durability of Concrete Structure is improved according to the variation of physical properties in concrete or the frequency of surface coating on concrete. Where, variation of physical properties is a water-cement ratio or amount of air. The experiments are the chliride ion diffusion test, the lapid corrosion test, the lapid carbonation test, the test on resistance to freezing and thawing. Finally, this study shows that the effect by the surface coating method is better than the variation of physical properties in concrete.

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High Power Circuit Analysis with the Simulation Technique using Physical Models of Power Devices (물리적인 전력소자 모텔을 이용한 대용량 인버터 시뮬레이션 기술)

  • Yoon Jae Hak;Schroder D.
    • Proceedings of the KIPE Conference
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    • 2002.07a
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    • pp.330-333
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    • 2002
  • The design of high power electronic circuits and the verification of the design by practical experiments are time and cost consuming. Recently power circuit simulation technique is developing to do it easily. However, most of the simulation has used the ideal switch model consists of passive component that can not describe the physical characteristics of semiconductor devices and cannot describe the switching transient state. For the design of such power electronic circuits by the simulation, the switching transients are very important. Therefore the simulation models must describe the switching transient and the stationary behavior as precisely as possible on the hand and as fast as possible the other hand. This paper introduces the application of the physical models of power devices that are developed by TUM(Technical University of Munich, Germany) for the power electronic circuit analysis.

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Studios on the Thin Rubber Coated Fabrics. (part 3) Physical properties of the Surface and Back Coated Fabrics with Rubber (박막(薄膜) Rubber Coated Fabrics에 관(關)한 연구(硏究) (제3보(第3報)) 각종(各種) 원반(原反)에 천연(天然) 및 합성(合成)고무를 양면(兩面) 도포(塗布)했을 때의 물리적성능(物理的性能)에 대(對)하여)

  • Kim, Joon-Soo;Lee, Myung-Whan;Yum, Hong-Chan;Lee, Chin-Bum;Rhim, Kwang-Kew
    • Elastomers and Composites
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    • v.2 no.1
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    • pp.31-36
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    • 1967
  • As a series of the studies of thin rubber coated fabrics, the experiments were concentrated on the investigation of the physical properties of the surface and back coated fabrics with natural and synthetic rubber. Cotton poplin and nine other cotton shootings were used as a base fabric and both sides of fabric, face and back, were coated by means of topping or spreading process. The physical properties of finished material were broadly investigated especially in view of the quality requirements of the poncho.

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Studies on the Physical properties and Application of EPDM-Polymer Blends. Part 3. Physical Properties for EPDM-BR Blends (EPDM과 각종(各種) Polymer의 Blend에 의(依)한 성능변화(性能變化) 및 그 응용(應用)에 관(關)한 연구(硏究)(제3보(第3報)) EPDM과 Butadiene Rubber의 Blend에 대(對)하여)

  • Kim, Joon-Soo
    • Elastomers and Composites
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    • v.7 no.1
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    • pp.38-44
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    • 1972
  • As a series of the studies of EPDM-polymer blonds, the experiments are concentrated to the investigation of the physical properties of the EPDM-BR blends. The results are shown as follows: 1. In blending, tensile strength and elongation decreased with increase in EPDM contents. 2. The resistance for aging and ozone were much improved after blending. It was effective more :han the ratio of EPDM/BR is 50/50. 3. Tear strength is less influenced after blending and rebound character decreased with increase in EPDM contents.

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Research on Physical Changes Based on Drying After Downpour Penetration of Floor Finishing Use Granite Stone (호우로 인한 바닥 마감용 화강석 침수 후 건조상태에 따른 물성변화에 관한 연구)

  • An, Ki-Won;Oh, Sang-Keun
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2015.05a
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    • pp.173-174
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    • 2015
  • This research takes granite stone based floor finishing exposed to concentrated downpouring and observes the material's physical changes, adhesiveness, compressive strength under wet conditions. The results of the experiments shows that elution of sulfide mineral can occur when granite stones are exposed to downpour, but short term exposure shows little physical changes to the material. This indicates that if post maintenance is properly enacted, long term usage of granite stone materials is also possible.

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