• 보존과학연구
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• s.31
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• pp.173-202
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• 2010

Within the framework of the Mongolian-Korean Joint Project for "Research and Preservation of Cultural Heritage", I enrolled in 3 months training course from February to May 2010 at the Metal laboratory of Conservation Science Division in National Research Institute of Cultural Heritage, Korea. Some metal artifacts, which are preserved in Institute of Archaeology, Mongolian Academy of Sciences, were brought and restored there. These chosen findings were found at Gobi and mountainous region of Mongolia, preserved under the different circumstances and dated back to Middle Age from Bronze Age. At the Metal laboratory of the NRICH, the conservation work was carried out for three months on 15 metal objects, including arrowhead, stirrup, caltrop, axe, knife, ring and so on, which were found at Khugshin Teel's ruin of Khairkhandulaan soum of Uvurkhangai province, Ungut of Altanbulag soum of Tuv province, Baruun Naran and Ukhaa khudag of Khankhongor and Tsogttsetsii soums of Umnugobi province. The report of the result of this conservation work is available here.

• Smart Structures and Systems
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• v.28 no.6
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• pp.839-853
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• 2021

In this paper, a novel multimode liquid metal-based pressure sensor is developed. The main body of the sensor is composed of polydimethylsiloxane (PDMS) elastomer. The structure of the sensor looks like a sandwich, in which the upper structure contains a cylindrical cavity, and the bottom structure contains a spiral microchannel, and the middle partition layer separates the upper and the bottom structures. Then, the liquid metal is injected into the top cavity and the bottom microchannel. Based on linear elastic fracture mechanics, the deformation of the microchannel cross-section is theoretically analyzed. The changes of resistance, capacitance, and inductance of the microchannel under pressure are deduced, and the corresponding theoretical models are established. The theoretical values of the pressure sensor are in good agreement with experimental data, implying that the developed theoretical model can explain the performance of the sensor well.

• Journal of the Korea Fashion and Costume Design Association
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• v.9 no.1
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• pp.71-87
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• 2007

Main role to expand the fashion in the middle age was played by aristocracy and knight. They contributed to the fashion of the middle age regardless of aesthetic sense. First, in any age, there was a self-display design using splendid decoration or material in the costume of high-class people. Aristocracy, especially, knight in the middle age classified themselves from others by wearing the costume suitable for their statuses. Second, the Crusade knight appearing all over the cinema gathered various peoples and caused acute optic angle about specialty of costume. Therefore the trend preferring foreign costumes was changed to new fashion while it was connected to desire searching for a change. Third, although armor of knight was created because of protection in the war, in the 13th century, its character of motion and defense was emphasized and it became splendid style. More over, the costume of knight was developed to more emphasize masculine beauty with heavy upper body and light lower body so it caused sexual difference of costume in the middle age. Fourth, As knight searched effective defensive weapon, chain mail was relegated by plate armor. The order of armor that the hight wore in 1350 was as follows. First, he wears adhesive shirts, braies, hose and wears metal protector on arm and leg. He wears padded undercoat called gambeson, hauberk, plate armor and surcoat on them.

• Journal of Society of Preventive Korean Medicine
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• v.5 no.1
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• pp.31-40
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• 2001

Legal permissible limit of herbal drugs metal level in Korea is define 'less 30.0ppm in total(except mineral drugs)' including Pb Hg Cd As Cr Ni etc. This limit has a lot of problems in several factors, that is, not divide hazard and essential elements, not consider high and low toxic effect in each metal, not calculate dose-response relationship and average health behavior in Korean etc. As a that result, It has strong limits and weakness in the basic toxicology and Oriental medicine. To improve and correct these factors, We need to several new approach as like below. It must be radical study following problems in short and middle-long period in the future, toxic metal and essential element must be divide to basic toxicology and also be diverse toxic effect. But mineral drugs that included a amount of severe toxic metals is being used as active prescription drug until now. If toxic, safety and side-effect of metals will be considered, mineral drugs must prohibit instantly or use at least after examined toxic effect. But one of the most important things about herbal drugs contamination, all people and department (government, farmer and trader, oriental medicine doctors and association) will be participate cooperative and collection for preventive or the least contamination in herbal drugs.

• Journal of Welding and Joining
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• v.15 no.2
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• pp.72-80
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• 1997

The spatter generation rate of GMA welding with $CO_2$ gas shielding was measured with the change of welding conditions such as wire feeding rate and welding voltage and then the results were analized with the accompanying changes in metal transfer mode and in bead geometry. The spatter generation rate (SGR) was relatively low not only wit the short circuit transfer but with the truely globular transfer mode. However, the SGR resulted with the mixed mode were consistantly high. The resultant wave pattern of mixed mode was due to the coexistance of short-circuit and globular transfer and characterized by the frequent appearance of instantaneous short circuit. Considering the result of SGR and that of bead geometry, it could be concluded that when the wire feeding rate (or welding current) was either low or high, the optimum bead shape could be obtained along with the low spatter generation. However, in the middle range of wire feeding rate, the optimum bead shape was only obtained in the mixed mode condition resulting in the high spatter generation.

• Transactions on Electrical and Electronic Materials
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• v.18 no.1
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• pp.13-15
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• 2017

Low emissivity glass for high transparency in the visible range and low emissivity in the IR (infrared) range was fabricated and investigated. The multilayers were have been fabricated, and consisted of two outer oxide layers and a middle layer of Ag as a metal layer. Oxide layers were formed by rf sputtering and metal layers were formed using by an evaporator at room temperature. SiInZnO (SIZO) film was used as an oxide layer. The OMO (oxide-metaloxide) structures of SIZO/Ag/SIZO were analyzed by using transmittance, AFM (atomic force microscopye), and XRD (X-ray diffraction). The OMO multilayer structure was designed to investigate the effect of Ag layer thickness on the optical property of the OMO structure.

• 한국금형공학회:학술대회논문집
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• 2008.06a
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• pp.31-34
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• 2008

The L-bending of inner-structure bonded sandwich sheet metal is examined to reduce springback and defects of bent parts. The specimen is composed of top and bottom layers and a middle layer with dimple type-inner-structure and each layer is bonded by resistance welding. This specimen with hollow type-inner-structure shows different bending characteristics from the conventional sandwich sheet metals with solid type-inner-structure. The experiments were conducted for two kinds of working conditions, that is, clearance and movement of first bent specimen for second bending. The deformed profile, bend angle and springback were investigated and compared and then the proper working conditions for L-bending of sandwich sheet metal were prosed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.05b
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• pp.34-37
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• 2004

It is well known that Ag-CdO alloy for electrical contactor has been widely used in weak or middle electric current field. But it is necessary to decrease Cd contents without decrease of contactor property because Cd is harmful to human body. The present work has been carried out to investigate effects of Mm (misch metal) addition on the property of Ag-CdO alloy for electrical contactor. As the results of present works, hardness and strength was improved and arc resistance was improved, also, in spite of decrease Cd contents by the Mm addition. It was estimated that Ag-oxide particle was refined by Mm addition.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.05a
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• pp.316-319
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• 2008

The L-bending of inner-structure bonded sandwich sheet metal is examined by using a bending die attached to the material testing machine. The specimen is composed of top and bottom layers and a middle layer of pyramid-core structure and each layer is bonded by brazing. The variables chosen for experiments were clearance between punch and die, location of bend line on the specimen surface and clamping type of specimen during L-bending. Effects of these variables on deformation of specimen around die-corner radius were investigated. It was shown that the irregular shapes of recess are formed in the inner layer of bended parts and they greatly depend on working conditions.

• Structural Engineering and Mechanics
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• v.62 no.6
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• pp.771-780
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• 2017

In this study, free vibration and damping behaviors of multilayered symmetric sandwich beams and single layered beams made of Functionally Graded Materials were investigated, experimentally and numerically. The beams were composed of Aluminum and Silicon Carbide powders and they were produced by powder metallurgy. Three beam models were used in the experiments. The first model was isotropic, homogeneous beams produced by using different mixing ratios. In the second model, the pure metal layers were taken in the middle of the beam and the weight fraction of the ceramic powder of each layer was increased towards to the surfaces of the beam in the thickness direction. In the third model, the pure metal layers were taken in the surfaces of the beam and the weight fraction of the ceramic powder of each layer was increased towards to middle of the beam. Then the vibration tests were performed. Consequently, the effects of stacking sequence and mixing ratio on the natural frequencies and damping responses of functionally graded beams were discussed from the results obtained. Furthermore, the results obtained from the tests were supported with a finite-element-based commercial program, and it was found to be in harmony.