• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.3
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• pp.543-548
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• 2010

There are produced the detent force caused by slot-teeth structures, end-effect and parallel magnetization of permanent magnet in permanent magnet linear synchronous motor. In this paper, we proposed to establish the auxiliary core for reducing detent force which is generated the discontinuity of magnetic circuits by end effect. The optimal design of the auxiliary core used a finite element analysis and design of experiment. To demonstrate the validity of the paper, the experiment results are compared with analysis ones.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1425-1426
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• 2015

Core spine muscle are related are associated with trunk stability and play a main role for the prevention of low back pain. In this study, it was investigated the effect of spine stabilization exercise device on core spinal muscles using a musculoskeletal model The forward direction of the tilt mainly induced the activation of long and superficial back muscles and the backward affected the front muscles. It was shown that spine stabilization exercise device can induce significant core muscle exercise effect.

• Structural Engineering and Mechanics
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• v.75 no.6
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• pp.643-657
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• 2020

This study presents experimental and numerical investigations on circular steel tube confined ultra high performance concrete (UHPC) columns under axial compression. The plain UHPC without fibers was designed to achieve a compressive strength ranged between 150 MPa and 200 MPa. Test results revealed that loading on only the UHPC core can generate a significant confinement effect for the UHPC core, thus leading to an increase in both strength and ductility of columns, and restricting the inherent brittleness of unconfined UHPC. All tested columns failed by shear plane failure of the UHPC core, this causes a softening stage in the axial load versus axial strain curves. In addition, an increase in the steel tube thickness or the confinement index was found to increase the strength and ductility enhancement and to reduce the magnitude of the loss of load capacity. Besides, steel tube with higher yield strength can improve the post-peak behavior. Based on the test results, the load contribution of the steel tube and the concrete core to the total load was examined. It was found that no significant confinement effect can be developed before the peak load, while the ductility of post-peak stage is mainly affected by the degree of the confinement effect. A finite element model (FEM) was also constructed in ABAQUS software to validate the test results. The effect of bond strength between the steel tube and the UHPC core was also investigated through the change of friction coefficient in FEM. Furthermore, the mechanism of circular steel tube confined UHPC columns was examined using the established FEM. Based on the results of FEM, the confining pressures along the height of each modeled column were shown. Furthermore, the interaction between the steel tube and the UHPC core was displayed through the slip length and shear stresses between two surfaces of two materials.

• International Commerce and Information Review
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• v.11 no.4
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• pp.25-45
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• 2009

This study tried to analyzed the relationship between core competence, satisfaction, trust and loyalty in order to suggest to a methodology for decision-making of e-trade firms. 6 hypothesis were constructed for analysis based on previous literature review. The results of empirical analysis shows that core competence gave significant effect on satisfaction, trust and loyalty, and satisfaction gave positively effect to trust and loyalty. Besides trust affected positively on loyalty. These result explains that e-trade firms which try to create customers must build high level of core competence should be realized and reacted for maintenance of created customers.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.435-441
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• 2010

In this study, numerical simulations were carried out to investigate the effect of verification core hole on the shaft tip capacity. The verification core extreted at shaft tip may deteriorate the shaft tip capacity when the clay shales (Taylor Marl) surrounding the shaft degrades and the empty core hole remains unfilled. Series of finite element analyses were conducted using Mohr-Coulomb model with total stress material parameters that were obtained from laboratory testing. The numerical analyses indicate that the shaft tip capacity does not decrease for most cases, and the maximum reduction does not exceed 5%.

• The Journal of Churna Manual Medicine for Spine and Nerves
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• v.8 no.2
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• pp.113-121
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• 2013

Objectives : The objective of this study is to report the effect of Traditional Korean medical therapy and core exercise on osteoarthritis of knee joint by observing a clinical case study. Methods : Patient with a diagnosis of osteoarthritis of knee joint, was treated by acupuncture, herb medicine, physical theraphy and core exercise. Results : After treatment, Visual Analogue Scale(VAS), Korean version of the Western Ontario and McMaster Universities(KWOMAC), Pain Rating Score(PRS) were reduced from 5 to 2, from 25 to 16, from 55 to 27, and CENTAUR test results were improved. Conclusions : This study showed that Traditional Korean medical therapy and core exercise has meaningful effect on osteoarthritis of knee joint, and more researches should be followed.

• Journal of Sensor Science and Technology
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• v.15 no.4
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• pp.263-268
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• 2006

We have demonstrated a highly sensitive temperature sensor using an etched single mode fiber with a thermally expanded core region. Large core size of thermally expanded core facilitates access to evanescent wave by the wet etching. The etched region was surrounded by a low dispersive external medium with high thermo-optic coefficient. Due to the large difference between the dispersion property of the fiber and that of the external medium, the device reveals a cut-off properties at spectral region. The cut-off wavelength was shifted by the variations of the environmental temperatures because of thermo-optic effect of the external medium. The sensitivity of the fabricated device was found to be $45nm/^{\circ}C$.

• Journal of the Korean Society for Precision Engineering
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• v.25 no.10
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• pp.115-121
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• 2008

This paper presents bisymmetric dual iron core lineal motor stage for heavy-duty high precision applications such as large area micro-grooving machines or high precision roll die machines. In this stage, two iron core linear motors are installed in laterally symmetric way to cancel out the attractive forces. Main focus was given to analyzing the effect of cogging force and moment for two different layouts, which are symmetric and half-pitch shifted ones. Experimental results showed that the symmetric layout is more adequate for high precision applications because of its clear moment cancellation effect. It was also verified that the effect of the residual cogging moment can be suppressed further by increasing the bearing stiffness. One problem of the symmetric layout is added cogging force which hinders smooth motion, but its effect was relatively small compared with that of moment cancellation.

• Nuclear Engineering and Technology
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• v.56 no.6
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• pp.2388-2394
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• 2024

In our previous works, two different spherical burnable poison particles (BPPs) as B₄C and Gd₂O₃ in pin-in block type HTGR core had utilized to suppress the excess reactivity and to control long-term reactivity during the burnup period. In the present work, we performed the neutronic analysis of a prismatic HTGR operating at 850 ℃ with thermal power of 100 MW containing spherical and cylindrical BPPs and then studied the self-shielding effect of BPPs and shape effect. The calculations were performed when the surface area (1) or volume (2) of cylindrical BPPs equals to that of the spherical BPPs. The calculations showed that the neutronic parameters were slightly better for the second case than the first one, such as the excess reactivity of the reactor core at the beginning of the cycle were more suppressed, the core lifetime were more extended, and the fuel-burning were more efficiently. The neutron spectrum in each region of the cylindrical BBPs slightly differs than that of the spherical BPPs. Therefore, the self-shielding effect of BPPs on reactor core performance depends on the particle's geometrical shape.

• Journal of Korea Foundry Society
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• v.9 no.5
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• pp.403-412
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• 1989

This study has been carried out to investigate into the properties of molding sands containing various core sands, $CO_2$, Shell, Furan, Pep Set and Cold Box, in the system sands using domestic active bentonite. The properties of system sands with 5% bentonite and 3% moistures containing baked core sands and no-baked core sands were varied by the ratio of core sands. The system sand containing no-baked core sands had been the poor bonding force and rough grain surface than those of the baked core sands. The L. O. I of system sand containing 30% organic binders core sands were more than inorganic binders core sands. It has been found that the no-baked core sands were necessary have to reclaim for using molding sand.