• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.22 no.3
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• pp.29-35
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• 1986

The characteristics of tidal exchange in Masan Bay were studied on the basis of salinity observations and current measurements in the summer of 1985. The exchange ratio of the sea water was calculated using three different formulas. The tidal exchange rate was estimated to be smaller than that of another bays in the southern coast of Korea. The tidal exchange ratios in Masan Bay at spring tide were deduced to be 2.4-11.7%. While those at neap tide were 2.0-9.1%. Though tidal range of neap tide is smaller than that of spring tide. the tidal exchange ratio in the bay can be increased in case of highly stratified vertical structure.

• Proceedings of the Korean Magnestics Society Conference
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• 2008.12a
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• pp.298.2-298.2
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• 2008

• Journal of Magnetics
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• v.16 no.2
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• pp.97-100
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• 2011

Bilayers of soft NiFe (150 nm-420 nm) on hard Ni (150 nm) were prepared by electrodeposition. The process of magnetization reversal in the NiFe/Ni bilayers was then investigated. The hysteresis loop generated by a magnetization reversal of soft NiFe under a positive saturation state of a hard Ni layer shows a shift along the negative field axis, which is clear evidence for the exchange spring effect in the NiFe/Ni bilayers. The dependence of the coercive field $H_c$ and exchange bias field Hex on the thickness of the NiFe layer was also investigated. As the NiFe thickness increases from 150 nm to 420 nm, both $H_c$ and $H_{ex}$ decrease rapidly from $H_c$= 51.7 Oe and $H_{ex}$ = 12.2 Oe, and saturate to $H_c$ = 5.8 Oe and $H_{ex}$ = 3.5 Oe.

• Journal of the Korean Magnetics Society
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• v.5 no.5
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• pp.404-407
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• 1995

Magnetic properties of model exchange-spring magnets, which are composed of magnetically soft and hard grains, were calculated by means of computer simulation. The dependence of the magnetic properties on the strength of intergrain exchange interaction and the amount of soft grains was studied. The existence of soft grains enhanced the remanence remarkably, and the remanence over $0.8M_{s}$ was obtained in the model magnets containing 25% or more soft grains by volume. The calculated coercivity vs. the strength of the exchange interaction curves showed a peak at a critical strength of the exchange interaction, although the remanence increased monotonously with increase in the strength of the exchange interaction. Thus the maximum energy product also reached a peak around the same critical strength. The calculated maximum energy product exceeded $300kJ/m^{3}$ when the magnet is assumed to be composed of $Fe_{3}B$ and $Nd_{2}Fe_{14}B$.

• Proceedings of the Korean Magnestics Society Conference
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• 2017.05a
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• pp.114-114
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• 2017

• Journal of the Korean Magnetics Society
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• v.22 no.5
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• pp.188-193
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• 2012

Permanent magnet is one of the most important parts in modern industry and the rare earth elements play an essential role for operation of permanent magnet. As is well known, the rare earth elements are mostly produced in China and the world is now facing serious problems owing to supply and demand imbalances. Many attempts have been performed to replace these rare-earth based permanent magnets by rare-earth free magnets, but they have not been successful so far. Regarding this issue, we discuss about an exchange spring magnet as a potential rare earth free permanent magnet structure.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 1994.10a
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• pp.5-25
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• 1994

The purpose of this paper is to provide the thermal comfort for humans using physiological principles of heat transfer and thermoregulation, heat exchange between the human body and its enclosur, and heat exchange between the inside enclosure and the outside environment.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.18 no.2
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• pp.101-108
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• 1985

The sea water exchange of Koje Bay in the southeastern part of the Korean Peninsula was estimated on the basis of current measurements and oceanographic observation. The exchange ratio was estimated by salinity differences and tidal prism method. The range of exchange ratio at the central part at the entrance of the bay is estimated to be around $26\%$ at spring tide and 5 to $15\%$ at neap tide. The magnitude of exchange ratio, however, can be changed due to water exchange, hydrometeorological and geomorphological conditions. The flushing time deduced by tidal prism was about 48 hours at spring tide and 81 hours at neap tide. Tidal induced eddy motion may play an important role on the seawater exchange in the bay.

• Environmental Engineering Research
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• v.11 no.2
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• pp.77-83
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• 2006

The hot spring water of the north Jeonla province such as Wanggung, Jookrim, Seokjung, and Hwasim, has fluoride concentration of 3.9 mg/L, 12.7 mg/L, 1.9 mg/L, and 6.3 mg/L, respectively. These figures fairly exceed the Korean and WHO standard for potable water, which is 1.5 mg/L. Therefore, in this study, research on elimination of fluoride in a hot spring water of Jookrim region, which has the highest level of fluoride concentration level in the north Jeonla province, was carried out. In analysis of Jookrim hot spring water according to the water quality standard for potable water, pH was very high at 9.25 and the concentration of fluoride was 10 times higher than the standard at 18.2 mg/L. Other measurements were within the standard or not detected. After injecting 10g of activated carbon for elimination of fluoride, the fluoride concentration was measured at 13.5 mg/L, and when 70mL or more of alum 10 g/L solution was injected, the concentration was measured at 2.8 mg/L, and injecting 3g of lime was measured at 9 mg/L. Alum showed the best elimination performance among all individual injections. Injection of 25 mL of activated carbon and 100 mL of alum solution together reduced the fluoride concentration down to 1.3 mg/L, which is under the potable standard. Injection of lime 1g and 75 mL of alum 10 g/L solution together reduced fluoride concentration to 4.1 mg/L. From the modifying HRT, by using ion exchange resin column, the pH was stabilized when HRT was Imin and showed range of $6.7{\sim}7.8$. The fluoride concentration reduced gradually as the HRT increased, and satisfied the potable standard when HRT passed 6 min, and after 30 min HRT, the concentration of fluoride was 0.05 mg/L: almost eliminated.

• Proceedings of the Korean Magnestics Society Conference
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• 2007.05a
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• pp.304.2-304.2
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• 2007