• Journal of the Korean institute of surface engineering
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• v.45 no.3
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• pp.136-141
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• 2012

'Jikjisimcheyocheal (Jikji afterwards)' is known as a first book printed by the metal type in the world. The metal type used for printing this book has not been found yet. To help for replicating the original metal type, it is required to investigate the composition analysis of the copied metal type. In this study, the composition analysis and thermodynamic care for replicating of ancient metal type was performed on the basis of an analytical reports concerned with the ancient metal type which made after Jikji printing. Metal types were made by remelting and casting of the mother alloy which came from a cast of a mixed metals in accordance with the composition revealed in the literatures. Change of composition during remelting of mother alloy and casting of metal was detected by the EDS analysis. The reasons for variation in composition were discussed by metallurgical and thermodynamic point of view, and a mixing ratio of metals to get the original composition of ancient metal type is suggested. Some attention should be paid on mixing, melting and casting of metals to get an objected composition for copy of ancient metal type.

• Proceedings of the KIEE Conference
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• 1997.07b
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• pp.714-716
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• 1997

In order to prevent the belt from being damaged by metal pieces, we developed multicoil-type metal detection system. This detects the presence of belt clips and position of metal pieces in ores being transported on conveyor belt. In this research, our coil sensor of multicoil-type metal detection system is divided into two parts, exciting part (transmitter coil) and sensing part composed of two receiver coils. Each receiver coil has several coils in the direction of belt width. Multicoil-type metal detection system is operated by supplying a transmitter coil with electric power resources to generate magnetic field, and then the change of magnetic flux resulted from a metal piece on the conveyor be a is induced into sensing coils. We can prevent detector from failing to catch metal pieces due to high threshold level produced by steel belt clips and male the sensitivity of belt-width direction uniform by using multicoil-type metal detection system. Besides, this developed system can recognize precise position and size of metal piece. The experiments shows that our multicoil-type metal detection system has better performances than the conventional metal piece detector.

• Journal of Environmental Health Sciences
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• v.29 no.3
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• pp.50-58
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• 2003

Removal of heavy metal ions (Cd$^{2+}$, Cr$^{3+}$, Cu$^{2+}$, Pb$^{2+}$) by several chitosans was studied and the molecular weight of chitosan was investigated in order to examine the effect of autoclaving. Chitosan were divided into 3 groups (A type, controlled chitosan; B type, autoclaved for 15 min; C type, autoclaved for 60 min). The heavy metal removal capacity and rate of B type chitosan were higher than those of A type and B type chitosan. The molecular weight of chitosan was decreased by the increase of autoclaving time. Therefore, the heavy metal capacity was not well correlated to the molecular weight. Freundlich and Langmuir isotherm was determined from the experimental results of equilibrium adsorption for individual heavy metal ions on chitosan. Langmuir isotherm was well fitted to this experimental data. The heavy metal removal capacity of B type chitosan was in the order of Pb$^{2+}$ > Cu$^{2+}$ > Cd$^{2+}$> Cr$^{3+}$.3+/.$.3+/.

• Journal of the Korea Institute of Military Science and Technology
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• v.15 no.4
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• pp.519-526
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• 2012

Recently fuel cell is considered to be a new technology that can substitute the ICE(Internal Combustion Engine) as well as overcome environmental issues. In military applications, fuel cell has an unique advantages, which are quietness, namely, stealth. The environmental requirement such as shock and vibration in military application, however, is very severe comparing to civilian demand. Especially, the safety concerning hydrogen storage is the most important problem. Among the candidate methods to store hydrogen, the metal hydride storage is promising method owing to the storage mechanism of chemical absorption of hydrogen to metal hydrides. In this study, the new composition of Ti-Zr type metal hydride(A composition) was suggested and investigated to increase the hydrogen storage capacity. For comparison, the hydrogen charge-discharge properties were investigated with the commercialized Ti-Zr type metal hydride(B composition) using PCT(Pressure-Composition-Temperature) measurement. Also two hydrogen storage cylinders were loaded with each metal hydride and their hydrogen charging and discharging characteristics were investigated. As a result, it was found that the new Ti-Zr type metal hydride has a slightly higher hydrogen storage capacity compared to commercial Ti-Zr type metal hydride.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1997.10a
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• pp.123-128
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• 1997

In-situ bearing metal temperature and shaft vibration are measured for an unload type and a preload type, m=0.87, of vertical guide bearing for hydraulic pump-turbines. Guide bearing is a tiltingpad type journal bearing consisting of eight pads whose diameter is 1,450 mm. Rotational speed is 450 rpm. Both the bearing metal temperature and the shaft vibration are very high in the unload type but are slight in the preload type, comparatively. The bearing metal temperature is decreased due to the increase of cooling effect by the increase of preload and the shaft vibration is decreased due to the increase of bearing stiffness. It is concluded that the preload effect of a guide bearing for hydraulic pump-turbines has a large influence on the bearing metal temperature and the shaft vibration.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.2
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• pp.239-244
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• 2008

In order to improve cost and efficacy of AC PDP with metal discharge electrodes, a new II-type metal electrodes are suggested. The suggested asymmetrical II-type metal electrode is improved in the luminance, power and efficacy than the conventional metal electrode by 7.5%, 6%, and 14%, respectively. The efficacy of the suggested asymmetrical II-type metal electrode is almost the same with the conventional ITO electrode. Moreover, the address time of the II-type metal electrode is shorter than the conventional ITO electrode.

• Journal of Korean Medical classics
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• v.24 no.3
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• pp.113-124
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• 2011

In this article the purpose of the study on Eulhae metal type(乙亥字) "Huangjenaegyeongsomun(黃帝內經素問)" is to ascertain the era of that publication according to recent investigation and find the properties of that book through comparision with other "Huangjenaegyeongsomun(黃帝內經素問)" published in ancient Korea, Choseon Dynasty. Because we are not yet secure more various Eulhae metal type(乙亥字) books and collaterally printed books, and there would be more unknown Eulhae metal type(乙亥字) "Huangjenaegyeongsomun(黃帝內經素問)" in Korea or abroad, so this study focuses on investigation of publish are only based on the record in that book, and comparision with the context of other Korea-published "Huangjenaegyeongsomun(黃帝內經素問)". As a result Eulhae metal type(乙亥字) "Huangjenaegyeongsomun(黃帝內經素問)" was published in Myeongjong era about 1554-1557, was the very original book of exiting Naeeuwon(內醫院) type "Huangjenaegyeongsomun(黃帝內經素問)". This Publication of this book published with Eulhae metal type(乙亥字) "Huangjenaegyeongyeongchu(黃帝內經靈樞)" at the same period explains that at that time Choseon Dynasty lay emphasis on promoting Medicine and teach "Huangjenaegyeong(黃帝內經)".

• Journal of Korean Library and Information Science Society
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• v.49 no.2
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• pp.25-58
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• 2018

This study analyzed the agriculutral book Gyemi Metal Type Sasichanyo which was produced in Jujaso(鑄字所), by early Joseon dynasty's king Taejo(太宗). It is the most advanced edition of Sasichanyo("四時纂要") among whole east-northern Asia, which contains miscellanies about monthly agricultural plan(月令式 農家雜錄) and the themes are; agriculture, production spin-off processing, sanitation and medicine, tool fixing and conservation, business management. This research divided all letters appeared in Gyemi metal type Sasichanyo("四時纂要") by three categories; small letters, smaller letters, smallest letters to define its' function and characteristics and estimated the value of Sasichanyo("四時纂要"). Also in the aspect of typeface of letters and typesettings, this study compared all editions of Sasichanyo("四時纂要") with Gyemi metal type Sasichanyo("四時纂要").

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.10
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• pp.877-882
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• 2005

In order to fabricate a high breakdown SiC-SBD (Schottky barrier diode), we investigate an effect on metal guard ring (MGR) in breakdown characteristics of the SiC-SBD. The breakdown characteristics of MGR-type SiC-SBD is significantly dependent on both the guard ring metal and the alloying time of guard ring metal. The breakdown characteristics of MGR-type SiC-SBDs are essentially improved as the alloying time of guard ring metal is increased. The SiC-SBD without MGR shows less than 200 V breakdown voltage, while the SiC-SBD with Al MGR shows approximately 700 V breakdown voltage. The improvement in breakdown characteristics is attributed to the field edge termination effect by the MGR, which is similar to an implanted guard ring-type SiC-SBD. There are two breakdown origins in the MGR-type SiC-SBD. One is due to a crystal defects, such as micropipes and stacking faults, in the Epi-layers and the SiC substrate, and occurs at a lower electric field. The other is due to the destruction of guard ring metal, which occurs at a higher electric field. The demolition of guard ring metal is due to the electric field concentration at an edge of Schottky contact metal.

• Journal of Welding and Joining
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• v.12 no.4
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• pp.151-161
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• 1994

FCAW has wide application in ship fabrication, maintenance and field erection. It has many advantages over SMAW.SAW and GMAW process. In many applications, the FCAW provides highquality weld metal. This method can reduce weld defects especially porosity and spatter. But the fatigue characteristics of those deposited metal have been rarely investigated. The purpose of this study is to investigate the cyclic stress-strain behavior and fatigue tests by the constant strain control were carried out on the rounded smooth specimen with deposited metal using the metal type flux cored wire. As the results of this study for the deposited metal welded by the metal type flux cored wire, the hardening or softening characteristics under cyclic load were investigated and cyclic stress-strain curve, strain-fatigue life curve, stress-strain function and fatigue life relation which are useful to estimate the fatigue life under the stress concentration condition were obtained.