• Journal of Advanced Marine Engineering and Technology
• /
• v.39 no.5
• /
• pp.527-535
• /
• 2015

As a new technical approach, a hydraulic and magnetic clamp device was attempted to realize a magnetic clamp crane system that uses 8 simultaneously actuating individual hydraulic cylinders. Through this approach, a Sr type of ferritic permanent magnet ($SrO{\cdot}6Fe_2O_3$), not the previously employed electro-magnet, was utilized for the purpose of lifting and transporting the heavy weighted and oversized curved steel plates used for manufacturing the ships. This study is aimed at manufacturing and developing the hydraulic magnetic clamp prototype, which is composed of three main parts - the base frame, cylinder joint, and magnet joint - in order to safely transport such curved steel plates. Furthermore, this research was pursued to conduct a performance evaluation as to the prototype manufacture and acquire the planned quantity value and the development purpose items. The most significant item for a performance evaluation was estimated for the magnetic adhesive force (G) and in this process, a ferritic permanent magnet (Sr type) with 3700~4000 G of residual induction (Br) and 2640/2770 Oe of coercive force (Hc) was utilized. In addition, other relevant items such as hoist tension (kN), transportation time (sec), and the applied load (Kgf) exerted on the hydraulic cylinders were also evaluated in order to acquire the optimum quantity value. As a result of the evaluation, the relevant device turned out to be suitable for safely transporting the curved steel plates.

• Proceedings of the Korean Magnestics Society Conference
• /
• 2007.05a
• /
• pp.261.1-261.1
• /
• 2007

• Proceedings of the Korean Magnestics Society Conference
• /
• 2005.06a
• /
• pp.24-25
• /
• 2005

• Journal of Institute of Control, Robotics and Systems
• /
• v.3 no.1
• /
• pp.67-76
• /
• 1997

In this paper we developed a tactile feedback device using repulsive force of magnets. The force of the tactile feedback device was derived from the Maxwell's stress method by using the concept of magnetic charge. Magnetic repulsive force is linear function with respect to current and nonlinear to displacement. Experimental data shows these characteristics. To compensate the fact that the presented tactile feedback device can not be controlled by close loop control, we developed a simulation model which predicts output displacement and force by using Runge-Kutta method. And, this paper evaluated the presented tactile feedback device and compared it with commercial tactile feedback devices.

• Proceedings of the Korean Magnestics Society Conference
• /
• 2006.11a
• /
• pp.38-38
• /
• 2006

• Journal of the Korean Society for Precision Engineering
• /
• v.22 no.3 s.168
• /
• pp.29-37
• /
• 2005

In this study, the control of the free surface deformation of a magnetic fluid for the change in electromagnetic force is discussed. The free surface of magnetic fluid is formed by the balance of surface force, gravity, pressure difference, magnetic normal pressure and magnetic body force. Magnetic fluid in characteristics of fluid adjusted to the opposite direction of the gravity direction. Thus, the device of a magnetic fluid proposed the complete zero-leakage sealing, oscillator for surface control, boundary layer control, MHD, flow control, flow using magnetic levitation system and surface actuator. This study show the deformation of surface rise due to the intensity of the magnetic field and possibility of two-dimensional control of magnetic fluid through the feedback data of hall sensor.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2003.06a
• /
• pp.1832-1835
• /
• 2003

This paper suggests the selective ultra precision polishing techniques for micro die and mold parts using magnetic-assisted machining. Fabrication of magnetic abrasive particle and their polishing performance are key technology at ultra precision polishing process of micro parts. Conventional magnetic abrasives have disadvantages. which are missing of abrasive particle and inequality between magnetic particle and abrasive particle. So, bonded magnetic abrasive particles are fabricated by several method. For example, plasma melting and direct bonding. Ferrite and carbonyl iron powder are used as magnetic particle where silicon carbide and Al$_2$O$_3$ are abrasive particle. Developed particles are analyzed using measurement device such as SEM. Possibility of magnetic abrasive and polishing performance of this magnetic abrasive particles also have been investigated. After polishing, surface roughness of workpiece is reduced from 2.927 $\mu\textrm{m}$ Rmax to 0.453 $\mu\textrm{m}$ Rmax.

• Journal of Magnetics
• /
• v.22 no.1
• /
• pp.14-22
• /
• 2017

The NMR's probe consists of the static magnetic field generator (magnetic source) and the RF coil. It is very strict for the homogeneity of the static magnetic field intensity of the magnetic source, so the cost of the magnetic source is more expensive in the entire nuclear magnetic resonance instrument. The magnetic source generally consists of electromagnet, permanent magnet and superconducting magnet. The permanent magnet basically needs not to spend on operation and maintenance and its cost of manufacture is much cheaper than the superconducting magnet. Therefore, the permanent magnet may be the only choice for the static magnetic field device if we want to use the magnetic resonance instrument as an analyzer for production by reducing price. A new probe magnet was developed on the basis of the permanent magnet ring in this paper to provide a technological way for reducing the manufacturing cost, weight and volume of the existing nuclear magnetic resonance instrument (including MRI) probe.

• The Journal of the Society of Korean Medicine Diagnostics
• /
• v.17 no.1
• /
• pp.63-76
• /
• 2013

The aims of this study are to investigate a logisitic regression equation of the vacuous pulse and the replete pulse for efficacy evaluation of clip-type pulsimeter by using magnetic Hall device. To evaluate the efficacy of clip-type pulsimeter by using magnetic Hall device as sensing the minute movement of a radial artery, one research clinical trial have been performed. The number of subject was 120, the clinical data of patients did treated with a normal statistical method. The systolic peak amplitude, the reflective peak amplitude and time, and the notch peak amplitude and time are analyzed major efficacy parameters to discern the vacuous pulse and the replete pulse. The equations included of five parameters such as systolic peak amplitude, the reflective peak amplitude and time, and the notch peak amplitude and notch amplitude time for determination of the vacuous pulse and the replete pulse were deducted by statistical logistic regression method. It suggests that the logistic regression equations are possible to develop the oriental algorithm for pulse diagnosis.

• Journal of the Korean GEO-environmental Society
• /
• v.14 no.2
• /
• pp.13-17
• /
• 2013

Clogging phenomenon in drainage system is one of the important problems and this phenomenon would be bad effect to structure of tunnel, so it needs a remedy urgently. Recently, scale in drainage pipe is removed by water jet cleaning and other treatment. But these treatments need much cost and regular management. In this study, magnetic device was used to solve this problem and an effect of prohibiting scale in accordance with array of magnetic device was investigated. Analysis method was visual analysis and measuring weight of each pipes. As a result, interior top and out-bottom (CASE II) was the most effective array to prohibit scale. and interior left and right (CASE III), interior top and bottom (CASE I) was effective for prohibiting scale in order.