• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.6
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• pp.72-80
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• 2013

For the proper cooling of in-wheel motor, the cooling channel should have the characteristics which are low pressure drop and adequate cooling oil supply to motor part. In this study, the flow performance of cooling channel for in-wheel motor was evaluated and the shape of the channel was optimized. First, the pressure drop and flow distribution characteristics of the initial channel model were evaluated using numerical analysis. Also, by the result of analysis and design modification, 4 design parameters of the channel were selected. Second, using the Taguchi optimal method, the cooling channel was optimized. In the method, nine models with different levels of the design parameters were generated and the flow characteristics of each models was estimated. Base on the result, the main effect of the design parameters was founded and optimized model was obtained. For the optimized model, the pressure drop and oil flow rate were about 0.196 bar and 0.207 L/min, respectively. The pressure drop decreased by about 0.3 bar and the oil flow rate to the motor part increased by about 0.2 L/min compared to the initial model.

• Journal of the Korea institute for structural maintenance and inspection
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• v.19 no.2
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• pp.1-9
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• 2015

In this paper, the RC column-based joint connection part carry out loading test by reinforced hollow or extended Base Plate in order to confirm that RC joint punching shear reinforcement effect of applying the Base Plate. Base Plate thickness, extension length, size, and type as the variable, Base Plate suitable for the stress distribution and shape and dimensions confirmed through experiment and then reinforcing effect was analyzed. Experimentally, vertical load transmitted to the Base Plate from column to foundation is effective to stress distribution and then, type of hollow reinforcement more efficient than a closed. Through experiment, improve performance and ductility due to reinforcement and relative to the thickness of the existing foundation reduced even showed better performance than the existing. The behavior of the reinforced specimens be able to induce from brittle to ductile. Experiment on loading to destroy performed the pattern of cracks, destruction aspect before and after reinforcement.

• Resources Recycling
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• v.25 no.6
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• pp.92-97
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• 2016

Spray dried $Cr_2O_3$ powder having an agglomerated structure of particles was twice treated into a plasma flame to increase its apparent density. The powder subjected to the first densification treatment did not show the entirely melted state keeping inner particle hollows, and it was fully melted after the second processing only. The powder size as a result of the second treatment decreased, and the apparent density as well as flowability were increased due to melting and surface smoothing effects. But a part of particles after the second densified treatment showed the hollow structure, especially those which were above $30{\mu}m$ in size. This densification behavior of the powder has been qualitatively discussed in terms of the thermal conductivity and inner gas pressure within aggregates exposed to the plasma flame.

• Transactions of Materials Processing
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• v.5 no.3
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• pp.219-231
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• 1996

The current five-stage cold extrusion process to produce an axle-housing is investigated for the purpose of improved process. The main goal of this study is to obtain an appropriate reduced process sequence which can produce the required part most economically without tensile crack-ing workpiece buckling and overloading of the tools. The current process sequence is simulated and design criteria are examined. during the simulation several remeshings are done due to severe mesh distortions, Based on the results of simulations of the current five-stage process, design strategy for improving the process sequence are developed using the thick hollow pipes. The finished product of an axle-housing is produced in two operations and one annealing treatment while the conventional sequence consists of five operations and one annealing treat-ment. Also die loads of the new process are compared with those of the current one.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.04a
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• pp.363-368
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• 2002

An automobile hub is composed of a hollow cylindrical part with inner and outer diameters. These hub diameters must be precise, as any irregularities in them (diameters) can influence/degrade the motion of an automobile with this problem. Highly accurate and reliable hub inner and outer diameters measurement systems are therefore required for inspection of the diameters. In this research, an automobile hub inner and outer diameters measurement system has been developed and tested. The system consists of measuring heads with LVDT sensors, and associated software for automatic measurement and calibration of the diameters and the sensors respectively. The system has been evaluated in comparison with an existing measurement system, and the following outcomes have been achieved; .Improved and guaranteed quality and reliability .Increased productivity and cost reduction. These results prove the system developed in this research to be suitable for automobile hub inspection.

• Journal of Electrical Engineering and Technology
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• v.10 no.5
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• pp.2001-2008
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• 2015

This paper proposes the concept of FlexPCB(flexible Printed Circuit Board) conductive structure for electrodynamic bearings. It has three main advantages: easy “printing” of considerably thin conductive wires, resulting in potential reduction in stray eddy currents; realization of specific conductive configurations with high precision to optimize the eddy current flowing; simplicity in being wound to cylinders or hollow cylinders of different diameters. To verify this new concept, the FlexPCB conductive structure was manufactured, an axial electrodynamic bearing test rig was built and the conductive structure's induced voltage was measured along the axial displacements from 0mm to 56mm at three rotating speeds. The finite element method was used to calcuatlate the flux density of electrodynamic bearing and induced voltage of the FlexPCB conductive structure. The experimental results are compared with the results from the FEM calculation. It is concluded that the measured and calculated induced voltages have consistency in the middle part of the bearing.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.12 s.255
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• pp.1503-1508
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• 2006

To increase the applicability and productivity of hydroforming process, hydro-embedding process was developed by combining the hydro-forming process with embedding process simultaneously. It is necessary in the automotive parts to form hollow bodies with connection elements which combine one part with another. The hydro-embedding process is embedding the connection element hydraulically during the operating steps of the hydroforming. In this study, technique of rotational piercing is added on the existing hydro-embedding to increase the connection force of hydro-embedded element. To estimate the feasibility of new trial process, integrated researches on the hydro-embedding process technology have been performed by analyzing the deformed mode of the tubes and the optimal process parameters for various shapes of the connection elements.

• Korean Journal of Environmental Biology
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• v.38 no.1
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• pp.160-164
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• 2020

Papenfussiella densa was described as Papenfussiella kuromo f. densa from Japan by Inagaki in 1958. P. densa has been recognized as an endemic and independent species based on the molecular analyses of type material without detailed morphological observations. In this study, Papenfussiella densa is reported as a new record from Dok-do, South Korea, based on morphological and molecular analyses. Papenfussiella densa is mainly characterized as having narrow, branched, slimy, and tomentose thalli with branchlets, partially hollow in the medulla of the middle part. The molecular analyses of the chloroplast rbcL-rbcS DNA sequence of the Papenfussiella densa sample from Korea revealed that it matched that of P. densa from Japan and was nested in the clade of Papenfussiella. There was only a 0.02% gene sequence divergence between the Korean and Japanese samples. We report P. densa as a new record from Korea and add this species to the list of Korean macroalgal flora.

• Proceedings of the KIEE Conference
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• 2000.11c
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• pp.547-549
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• 2000

Silicone insulators have many advantages over porcelain insulators. Especially silicone insulators have good characteristics of impact hardness, surface insulation, ease of processing, mass productivity and don't have risk of bombardment and vandalism. Recently insulation part made by silicone are becoming widely used. In this paper we introduce the development of Sealing End for 132kV XLPE cable with silicone composite hollow insulator and the adoption of it to a actual transmission line in abroad. This paper contains of design procedure, structure, electrical performance of it.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.2
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• pp.130-137
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• 2017

Due to the economic growth and development of construction technology, a role of foundation to resist heavy loads has been increased. In this present study to improve the structural performance of reinforced concrete pile, the precast HPC pile reinforced with rebar and filling concrete was developed and the strength of pile was predicted based on the limit state design method. The safety of HPC pile strength was evaluated by comparing with the design values. The geometry of HPC pile is a decagon cross section with a maximum width of 500 mm and a minimum width of 475 mm, and the hollow head of pile thickness is 70 mm. The inner area of the hollow head part was made as the square ribbed shape presented in the limit state design code in order to achieve horizontal shear strength between pile concrete and filling concrete. From the shear test results, it was found that the stable shear strength were secured without abrupt failure until maximum load stage despite the shear cracks was found. Shear strength is 135% and 119% higher than that of design value calculated from limit state design code. The driving test results of HPC pile according to the presence of additional reinforcement showed the outstanding crack resistance against impact loads condition. From the bending test results the flexural load between PHC pile and HPC pile was 1.51 times and 1.48 times higher than that of the design flexural load of conventional PHC pile.