• The Journal of Engineering Geology
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• v.20 no.1
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• pp.71-78
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• 2010

The Gagok mine is a contact metasomatic deposit, located at Gagok-myeon, Samcheok city and Cheoram-dong, Taebaek city, Gangwon province. The deposit lies within the limestone of Myobong and Pungchon formations, and exists the contact of intrusive granite porphyry. In order to determine the direction and extension of mineralization in the gallery and around the entrance of the ore deposit, we used the ground magnetic survey, the direct current (dc) resistivity survey using dipole-dipole array, and resistivity tomography survey. The ground magnetic survey did not detect the anomalous zone due to ore deposit, while the dc resistivity survey and resistivity tomography survey were successful in delineating the anomalous zone related to the extension of fault toward $N50^{\circ}W$.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.135-136
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• 2012

Carbon atoms near the surface of W(110) induce reconstructions such as $R(15{\times}12)$ -C/W(110) which consists of two characteristic parts, one square shaped and bright protrusion and two smaller ones. In the atomic resolution STM image, the bigger protrusion shows the periodicities of clean W(110), indicating that it is almost carbon poor region. The smaller protrusion contains hexagonal carbide surface layer of ${\alpha}$-W2C on W(110). Employing this carburized W(110) as templates, we grow Co and Fe clusters of less than ten atoms. Due to the selectivity of bonding sites, growth of larger cluster is highly unfavorable for Co and the size of clusters is very uniform. Since Co atoms prefer to sit on the bigger protrusion rather than smaller one, Co cluster can be arranged one-dimensionally in $R(15{\times}12)$-C/W(110) with quite uniform size distribution. However, Fe clusters sit on both sites without favored site, but still with uniform size distribution. On the other hand, Fe clusters can be grown with quasi one-dimensional order in $R(15{\times}3)$-C/W(110), which consists of only smaller protrusions. We investigate the magnetic properties of the ordered nano-sized clusters. Experiments using XMCD reveals little magnetic moment of Co cluster on $R(15{\times}12)$-C/W(110). This observation is consistent with the predictions of our first principles calculations that small Co clusters can be nonmagnetic or antiferromagnetic with low mean magnetic moment per atom.

• Economic and Environmental Geology
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• v.35 no.2
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• pp.155-162
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• 2002

There are many typical epithermal deposits scattering in the Taran of central Kalimantan. Indonesia. To get the shallow geological information, we carried out the geophysical exploration: spontaneous potential survey, in-suite magnetic susceptibility measurement and relistivity survey method in this area for a few weeks from September 30th to October 27th in 1997. SP survey (Fluke 27 multimeter)/magnetic susceptibility (EK -7 meter) measurement was carried out with a 250m$\times$10m lattice net in N45$^{\circ}$W direction. The dipole-dipole array resistivity survey was conducted with an electrode spacing of ${\alpha}$=30 m and electrode separation index n=7 at the line 5. The result shows that was the gold bearing quartz vein area can be divided into two type lone: low sulfidation type and high sulfidation type zone. The low resistivity value in the survey line 5 indicated a fracture Bone associated with the high sulfidation zone.

• Journal of Electrical Engineering and Technology
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• v.1 no.3
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• pp.338-342
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• 2006

This paper analyzed the power loss of transformers considering the magnetic component. For this, each winding strategy and the effect of air gap between the ferrite core have been an important variable for optimal parameter calculation. Inductors are very well known design rules to devise, but the performance of the flyback converter as a function of transformer winding strategy has not been fully developed. The transformer analysis tool used was PExpert. The influence of the insulator thickness, effect of the air gap, how the window height and variation of the capacitive value effects the coil and insulator materials are some of parameters that have been analyzed in this work. The parameter analysis is calculated to a high frequency of 48[kHz]. Therefore, the final goal of this paper was to calculate and adjust the parameters according to the method of winding array and air gap minimizing the power loss.

• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.1226-1228
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• 2002

Permanent magnet is applied to the mover of eddy current braking system for high speed. On the analytical 2D field solutions considering end effect, this paper deals with the magnetic field, and forces according to the secondary magnet array. Comparisons between analytical results and experimental results are also presented.

• Proceedings of the KIEE Conference
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• 1997.07f
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• pp.1924-1926
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• 1997

With the development of power electronics, many new energy storage systems such as the superconducting magnetic energy storage, the flywheel energy storage, and the capacitive energy storage, etc. are being intensively studied recently in order to replace battery in some special applications, Among these innovative energy storage systems, the flywheel system exhibits some unique features such as high power density, easy maintenance and longer lifetime. This paper introduces the novel flywheel energy storage system. Operation and features of the system are illustrated and verified on a 6kVA, 20kHz IPM based experimental circuit for O/A application. The Halbach Array Motor is selected of the design of the three phase motor/generator for the flywheel energy storage system.

• Proceedings of the KIEE Conference
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• 2003.04a
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• pp.119-121
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• 2003

In the machine tool industry, direct drive linear motor technology is of increasing interest as a means to achieve high acceleration, and to increase reliability [1]. In this paper, we analyze and compare the characteristics of tubular motor with halbach and vertical magnet array respectively. We derive magnetic field solutions due to the PMs and to the currents. Motor thrust is then derived. The results are shown in good conformity with those obtained from the commonly used finite element method.

• Proceedings of the KIEE Conference
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• 2004.10a
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• pp.80-82
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• 2004

This paper deals with design of linear switched reluctance motors(LSRM) which drive a testing machine of eddy current magnetic repulsion system using Halbach array and conducting plate. The design method employing finite element method and parameter estimation method and a characteristic of LSRM according to variation of parameter is introduced.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.580-582
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• 2001

In moving coil LOA, the variation of mover position and the consequent changes of coil flux path affect the coil inductance because of unbalanced magnetic circuit. Furthermore, the armature field shifts and distorts the airgap flux density distribution due to the magnet alone by a certain amount, which cause the unbalanced reciprocating force. In this paper, we propose the reduction method of armature reaction and coil inductance. The proposed LOA has the shorted ring the saturated core, the double coil, and Halbach array.

• The Transactions of the Korean Institute of Power Electronics
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• v.18 no.2
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• pp.117-122
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• 2013

The distributed power conversion LED driver circuit using parasitic inductance is proposed in this paper. while the conventional LED driver circuit is composed of the large size devices and heatsinks, the proposed circuit can be realized with the small sized no heatsink based. since the processing power can be effectively distributed. Also by using the wire parasitic inductance of the LED string, the proposed circuit can be implemented without external magnetic device. As a result, the proposed circuit which features the small size and volume con be realized even without LED driver module(LDM) board. since, all the device can be attached to the existing LED array Module(LAM) board. Therefore, it features that cost savings and volume reduction of circuit. To confirm the validity of the proposed circuit, theoretical analysis and experimental results from a distributed power conversion LED driver circuit prototype are presented.