• Progress in Superconductivity and Cryogenics
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• v.20 no.2
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• pp.1-5
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• 2018

Arsenic (As) is one of the elements having most harmful impact on the human health. Arsenic is a known carcinogen and arsenic contamination of drinking water is affecting on humans in many regions of the world. Adsorption has been proved most preferable technique for the removal of arsenic. Many researchers have studied various types of solid materials as arsenic adsorbent, and iron oxide and its modified forms are considered as the most effective adsorbent in terms of adsorption capacity, recovery, and economics. However, most of all iron oxides have small surface area in comparing with common adsorbents in environmental application such as activated carbon but the activated carbon has weak sorption affinity for arsenic. We have used an activated carbon as base adsorbent and iron oxide coating on the activated carbon as high affinity sorption sites and giving magnetic attraction ability. In this study, adsorption properties of arsenic and magnetic separation efficiency of the magnetized activated carbon (MAC) were evaluated with variable iron oxide content. As the iron oxide content of the MAC increased, adsorption capacity has also gradually increased up to a point where clogging by iron oxide in the pore of activated carbon compensate the increased sorption capacity. The increase of iron oxide content of the MAC also affected magnetic properties, which resulted in greater magnetic separation efficiency. Current results show that magnetically modified common adsorbent can be an efficiency improved adsorbent and a feasible environmental process if it is combined with the magnetic separation.

• Journal of Navigation and Port Research
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• v.27 no.4
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• pp.413-424
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• 2003

Up to now it has been widely conceived that mariner's compass was introduced to Europe from China via the Arabic people. But the proofs to support the above orthodox dissertation have not been found yet. In general it has been approved that the Chinese used the compass for navigation in the 11th century and European did in the 12th century. During the above period the communication between the Europe and the China was made only by the mediation of the Arabic people. But it is known that the beginning of Arabic people's compass usage was one century later than that of the European. It may raise a historical question about ‘was mariner's compass introduced to Europe from China via the Arabic people\ulcorner’ In this paper the authors tried to prove the simultaneity of the mariner's compass usage by the European with the Chinese by reviewing historical materials and modern researches. The results are as following; The first, there is a strong similarity in the evolving steps of compass appliance of both civilizations, such as from using magnetized and pivoted needle to fixing card thereto. Second, the Chinese and the European started to use the mariner's compass almost at the same time, and they developed it independently.

• Journal of The Korean Astronomical Society
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• v.37 no.5
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• pp.413-420
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• 2004

The current state and future prospects of ultra high energy cosmic ray physics are reviewed. These cosmic rays with energies well above $10^{18}$ eV are messengers of an unknown extremely high-energy universe.

• The Bulletin of The Korean Astronomical Society
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• v.31 no.1
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• pp.37.1-37.1
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• 2006

• Proceedings of the Korean Magnestics Society Conference
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• 2015.11a
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• pp.75-76
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• 2015

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.11a
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• pp.931-932
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• 2010

• Proceedings of the Korean Magnestics Society Conference
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• 2008.12a
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• pp.202.1-202.1
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• 2008

• Journal of Magnetics
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• v.21 no.3
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• pp.450-459
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• 2016

Experimental results and data of numerical simulations are presented, concerning generation of wideband radio frequency (RF) oscillations in a nonlinear transmission line (NLTL) which contains a pre-magnetized core of ferrite material. Emphasis is made on the means for extracting the RF signal from the line, in order to radiate it into free space. Antennas of two types that can be used for the purpose are considered, both featuring a coaxial design. This permits availing of the principal advantages of coaxial systems, such as operation in the mode of a traveling TEM wave; wide range of the transmitted frequencies, and a reasonably simple design. The antennas studied, specifically a disc-cone dipole (DCD) and an impulse reflector antenna ('Half-IRA', or HIRA type) differ significantly in effective width of the radiated spectrum and in spatial characteristics of the radiated field in far region.

• Journal of The Korean Astronomical Society
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• v.37 no.5
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• pp.575-578
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• 2004

High resolution observations of cluster of galaxies by Chandra have revealed the existence of an X-ray emitting comet-like galaxy C153 in the core of cluster of galaxies A2125. The galaxy C153 moving fast in the cluster core has a distinct X-ray tail on one side, obviously due to ram pressure stripping, since the galaxy C153 crossed the central region of A2125. The X-ray emitting plasma in the tail is substantially cooler than the ambient plasma. We present results of two-dimensional magnetohydrodynamic simulations of the time evolution of a sub clump like C153 moving in magnetized intergalactic matter. Anisotropic heat conduction is included. We found that the magnetic fields are essential for the existence of the cool X-ray tail, because in non-magnetized plasma the cooler sub clump tail is heated up by isotropic heat conduction from the hot ambient plasma and does not form such a comet-like tail.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.7
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• pp.63-68
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• 1994

The Curie point annealing effects on electrophysical phenomena at the magnetized strontium ferrite(SrO$\cdot$ 6$Fe_{2}O_{3}$) ceramics electrode/10$^{-3}$M KC1 aqueous electrolyte interfaces have been studied using cyclic voltammetric, normal pulse voltammetric, chronocoulometric, and electrochemical impedance techiques. After the Curie point annealing the magnetic flux densities of the speciment was decreased from 900-1100 gauss to 1-2 gauss, i.e. demagnetized. The real component of interfacial impedance was decreased from 7280-7320 ohm to 790-830 ohm. The adsorption and the charge on the electrical double layer was increased from 0 $\mu$C to -58 $\mu$C. The Curie point annealing and the related electrical double layer effect can influence not only the electrophysical properties of the strontium ferrite ceramics electrode itself but also the electrochemical phenomena at the electrode interface. This experimental results suggest that the Curie point annealing and the related electrical double layer effect can be applied to electrochemical magnetic sensors.