• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제50권4호
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• pp.158-163
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• 2001

Magnetization losses of a Bi-2223 tape in magnetic fields parallel to the tape surface were measured by a room temperature cancellation and a cryogenic temperature cancellation. The results indicate that the same loss data are observed for both methods. The magnetization losses are hysteretic because the measured losses agree well with calculated ones based on a critical state model. In the full field penetration cases the magnetization losses increase with the frequency but in the partial field penetration cases the influence of the frequency is opposite.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.120.4-120
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• 2001

In this paper, a method of generating trajectories in real time for a mobile robot in a dynamic environment is proposed. Specifically, this method is focused on soccer-playing robots that need to calculate trajectories in real time, which are constantly subject to rapidly change as targets and obstacles move. The robots also should move at the fastest available speed, while tracking the generated trajectories. The method proposed in this paper solves the geometric problem of finding a smooth curve that joins two endpoints. To have this solved, we assign five constraints to each endpoint, which are the usual x, y, theta, and curvature as well as the influence of the initial robot velocity on the path. With these five constraints, the path generated can always be physically followed by robot. Through this method, the travel time of the robot over the entire path can b optimized. Therefore it can ...

• 대한기계학회논문집A
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• 제29권3호
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• pp.411-417
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• 2005

Surface texturing of tribological application is another attractive technology of friction reducing. Also, reduction of friction is therefore considered to be a necessary requirement for improved efficiency of machine. In this paper attempts to investigate the effect of density for micro-scale dimple pattern using photolithography on bearing steel flat mated with pin-on-disk. We demonstrated the lubrication mechanism for a Stribeck curve, which has a relationship between the friction coefficient and a dimensionless parameter for lubrication condition. It is found that friction coefficient is depended on the density of surface pattern. It was thus verified that micro-scale dimple could affect the friction reduction considerably under mixed and hydrodynamic lubrication conditions from based on friction map. Lubrication condition regime has an influence on the friction coefficient induced the density of micro dimple.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 춘계학술대회 논문집
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• pp.533-539
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• 1997

Pressure ripple of hydraulic vane pump results form flow ripple due to pump geometry and reverse flow through the discharge port due to compressibility of fluid and result in vibration and noise of connected hydraulic elements. In a ba;anced type vane pump, cam ring curve is important factor to influence the flow ripple. Therefore, to reduce the now ripple, it has been required that optimal selection of seal region by proper design of cam ring and each port position, and notches for preventing the excessive reverse flow. This paper has been performed analytical study of compression characteristics with major design parameter in side plate and cam ring, and examined into the role of notch and radius reduction ratio.

• 대한기계학회논문집A
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• 제27권6호
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• pp.914-922
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• 2003

In this paper, the strain localization of voided ductile material has been analyzed by nonlocal plasticity formulation in which the yield strength not only depends on an equivalent plastic strain measure (hardening parameter), but also on the Laplacian thereof. The gradient terms in yield criterion show an important role on modeling strain-softening phenomena of material. The influence of the mesh size on the elastic -plastic deformation behavior and the effect of the characteristic length parameter for localization prediction are also investigated. The proposed nonlocal plasticity shows that the load -strain curves converge to one curve. Results using nonlocal plasticity also exhibit the dependence of mesh size is much less sensitivity than that for a corresponding local plasticity formulation.

• Computers and Concrete
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• 제19권3호
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• pp.227-232
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• 2017

This paper describes an experimental study of the cyclic performance of concrete beams reinforced with CFRP prestressed concrete prisms (PCP). The failure modes, hysteretic loops, skeleton curve, ductility, energy dissipation capacity and stiffness degradation of concrete beams reinforced with CFRP prestressed concrete prisms were analyzed. The results show that The CFRP prestressed prisms reinforced concrete beams have good seismic performance. The level of effective prestress and cross section of CFRP prestressed prisms had a little influence on the bearing capacity, the ductility and energy dissipation capacity of CFRP prestressed prisms reinforced concrete beams.

• 대한화학회지
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• 제15권6호
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• pp.324-329
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• 1971

In order to evaluate the mechanism of electrolytic oxidation of iodate and to determine the optimum conditions for the electrolysis, studies were made using the cells without diaphragm and the lead peroxide anode. Results are summarized as followings: 1) Current density vs. anode potential curve by lead peroxide electrode had the different limiting current densities from platinum electrode and was more positive than platinum electrode. 2) Additions of potassium bichromate in the electrolyte contribute to maintain high current efficiency. 3) In the acid and alkaline regions, the current efficiencies decreased by reduction of iodate and discharge of hydroxyl ion, so maximum current efficiency was shown at pH 7. 4) Higher current density lowered the current efficiency in the region of 60-80% conversion of iodate. 5) Influence of the conversion on current efficiency in the region of 60-80% conversion of iodate.

• 한국정밀공학회지
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• 제15권1호
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• pp.87-93
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• 1998

Pressure ripples of hydraulic vane pump results from flow ripples due to pump geometry and reverse flow through the discharge port due to compressibility of fluid and result in vibration and noise of connected hydraulic elements. In a balanced type vane pump, cam ring curve is important factor to influence the flow ripples. Therefore, to reduce the flow ripple, it has been required that optimal selection of seal region by proper design of cam ring and each port position, and notches for preventing the excessive reverse flow. This paper has been performed analytical study of compression characteristics with major design parameter in side plate and cam ring. and examined into the role of notch and radius reduction ratio.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 봄 학술발표회 논문집
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• pp.565-570
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• 2000

The objective of this paper is to analyse the high-strength concrete columns subjected to reversed cyclic and axial loads by using nonlinear analysis model and compare the experimental results with analysis. The analytical parameters are the compressive strength of concrete, spacing of lateral reinforcement and lateral reinforcement ratio. In this study, the proposed analytical model takes ito account the influence of confined concrete, tension stiffening and strain hardening of steel. The high-strength concrete columns are used to model fiber section element. The analysis results are shown comparatively good prediction on envelope curve, accumulative dissipated energy, deformability and so on.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.113-114
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• 2008

For the supported high-technology, it is in need of estimation about power quality and reasonable price through machinism. The power system made much of precision digital industrial damage under sag. This study suggested electric machine under effects of power quality in the theory and test. A electric machine was simulated and experimented about sag. The test system made up IPC as voltage sag device. The test machine was magnetic contactor and PLC. The result, electric machines appeared to influence sag with CBEMA curve. It was make possible analysis of power system about a fault. This study was expected to method that investment and development of equipment on power market in the future.