• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2003년도 가을 학술발표회 논문집
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• pp.429-432
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• 2003

MMA-modified fiberglass-reinforced plastic composite pipe was produced by using the binder of MMA-modified unsaturated polyester resin in which low viscosity MMA was added to unsaturated polyester resin. Sixteen specimens were made of polymer mortar and fiberglass-reinforced plastic by the centrifugal method. For these specimens the external strength tests were carried out by taking the core thickness consisting of polymer mortar and the fiberglass content per unit area as experimental variables to figure out the effect of variations of these variables influencing on flexural rigidity that is an important property for the composite pipe. Results of this study are believed to provide the basic data for more economical and practical design of MMA-modified fiberglass-reinforced plastic composite pipe.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2005년도 춘계학술대회 논문집
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• pp.661-666
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• 2005

In this Paper, to calculate vertical earth pressure affected from several factors in case of rigid buried pipe with cohesionless backfill soil. The result from PENTAGON 3D is compared with several equation's result such as the Janssen, Marston, Spangler, Handy's equation. Result of study shows that vertical earth pressure of each equation is affected by backfill width, backfill depth and wall friction. And vertical earth pressure is linearly increased with backfill depth and backfill width. Marston's equation and Handy's equation are overestimated and FEM(Finite Element method) analysis and Janssen's Silo equation are affected by more backfill depth than backfill width.

• 소음진동
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• 제10권6호
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• pp.1035-1040
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• 2000

The Impingement of a weak shock wave discharged from the open end of a shock tube upon a flat plate was investigated using shock tube experiments and numerical simulations. Harten-Yee Total Variation Diminishing method was used to solve axisymmetric, unsteady, compressible flow governing equations. Computations predicted the experimented results with a good accuracy. The peak pressure on the flat plate was not strongly dependent of the shock wave Mach number in the present range of Mach Number from 1.05 to 1.20. The distance between the plate and shock tube was changed to investigate the effect on the peak pressure. From both the results of experiments and computations we obtained a good empirical equation to predict the peak pressure on the flat plate.

• 대한방사선협회지
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• 제28권1호
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• pp.55-60
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• 2002

Purpose : The aim of this study is to rise interest in system control for digital image of high quality by investigating diagnostic value of Digital radiographic system in upper gastrointestinal study Materials and Method : Upper gastrointestinal study wa

• Elastomers and Composites
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• 제17권1호
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• pp.13-21
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• 1982

The purpose of this dissertation is to compare bound andtioxidant, MHPPD with the ordinary one, IPPD, when high polymers are used like NR and SBR. The effect of rubber bound antioxidant and ordinary antioxidant on the Mooney scorch time has been studied by means of the Mooney viscometer. The ageing properties of vulcanizates containing rubber-bound antioxidant and ordinary antioxidant have been studied in terms of hardness, tensile strength and elongation. The results of the Mooney scorch time and ageing properties are as follows: When MHPPD was mixed with NR or SBR compounds, the Mooney scorch time was faster than the IPPD compounds. Also the ageing properties of the vulcanizates containing MHPPD were much superior to the IPPD compounds. Furthermore, the vulcanizates comporised of MHPPD have taken andvantage of and resistance in the ozone test.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.2146-2150
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• 2004

To evaluate the variation of spring stiffness in nuclear plant operating condition, load-displacement tests ($P-{\delta}$ test) were performed using two kinds of space grid springs in high temperature and high pressure water. With increasing temperature, stiffness of each spring gradually decreased except $100{\sim}150^{\circ}C$. It is apparently showed that spring with convex shape had a relatively high stability of spring stiffness at high temperature compared with I-shaped spring. It is suggested that the variation of spring stiffness with temperature and spring shape should be considered as an important variable in the design and analysis of the fuel assembly.

• 한국기계가공학회지
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• 제12권6호
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• pp.167-174
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• 2013

High speed rotor systems with magnetic bearings have been the subject of much research in recent years due to the potential for active vibration control. In this thesis, optimal design was conducted for an 8-pole heteropolar magnetic bearing used in the flexible rotor of a turbo blower. In connection with bearing stiffness, this optimal design process was conducted using a genetic algorithm(GA), which is based on natural selection and genetics. The maximum stiffness of the magnetic bearing-rotor was found by considering the critical speeds of the flexible rotor. As a result, the magnetic bearings were optimized to have maximum stiffness.

• 대한기계학회논문집
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• 제17권11호
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• pp.2694-2703
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• 1993

In the vibration analysis of Timoshenko beams by the finite element method, it is necessary to use a large number of elements or higher-order elements in modeling thin beams. This is because the overestimated stiffness matrix due to the shear locking phenomenon when lower-order displacement-based elements are used yields poor eigensolutions. As a result, the total number of degrees of freedom becomes critical in view of computational efficiency. In this paper, the curvature-based formulation is applied to the vibration problem. It is shown that the curvaturebased beam elements are free of shear locking and very efficient in the vibration analysis.

• 한국군사과학기술학회지
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• 제2권2호
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• pp.92-98
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• 1999

Dynamic behavior of missile which is fired in canister is analyzed by flexible multibody dynamics. The bending elasticity of missile is very important in case that missile is fired in the inclined launcher. In this paper, the force element model for the missile launching stage and the finite element model of missile are developed. The FEA model of missile is condensed into five lumped mass element model and the consistence between FE model and lumped mass model of missile is verified by modal analysis. As a result of analysis, sabot reaction force and pitch rate of missile for the variation of gap size and force element are obtained.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2011년도 제36회 춘계학술대회논문집
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• pp.279-282
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• 2011

가스 발생기 산화제 개폐 밸브에 사용되는 벨로우즈의 구조 해석 및 시험이 수행되었다. 해석은 상온 및 극저온에서 EJMA (Expansion Joint Manufacturing Association) 표준 및 상용 유한 요소 해석프로그램인 Abaqus v6.9를 이용하여 수행되었다. 스프링 강성, 응력 및 피로 수명 해석 결과들이 비교되었고 유한 요소 해석 결과에서 접촉 및 재질의 소성에 의한 영향을 살펴보았다.