• Journal of Conservation Science
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• v.26 no.1
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• pp.13-24
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• 2010

This study examined each handiwork method of 4 filigree artifacts from Neungsan-ri temple site in Buyeo, Korea through material characteristic and microstructure analysis. As a result, it was indicated that all of the artifacts have comparatively higher purity than 22.7K and some of filigree artifacts showed that gold is alloyed with silver at a certain ratio. Gold thread that decorates surface showed thickness of 0.2~0.8mm and displayed various forms of section. Gold granule indicated that 2 or 3 granules are adhered together and they are 0.3~0.8mm in diameter. Trace of soldering was observed from gold thread and gold granule joints on surface and it confirmed a possibility of being soldering using gold solder through componential analysis. Also, it reveals a surface decorated with pigments such as cinnabar(HgS) and black.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.12
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• pp.8679-8683
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• 2015

Using a surface modification technique, ion beam assisted deposition (IBAD) of Ti thin film it becomes possible to prepare an active ceramic surface to braze $Al_2O_3$-STS304 with conventional Ag-Cu eutectic composition filler metal. Researches on bonding formations at interfaces of ceramic joints were mainly related on the development of filler metals to ceramic, the process parameters, and clarifications of reaction products. From the results, the reactive brazing is a very convenient technique compared to the conventional Mn-Mo method. However melting point of reactive filler is still higher than that of Ag-Cu eutectic and it forms the brittle inter metallic compound. Recently several new approaches are introduced to overcome the main shortcomings of the reactive metal brazing in ceramic-metal, metal vapor vacuum arc ion source was introduced to implant the reactive element directly into the ceramics surface, and sputter deposition with sputter etching for the deposition of active material.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.477-477
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• 2008

For more than three decades, the gate dielectrics in CMOS devices are $SiO_2$ because of its blocking properties of current in insulated gate FET channels. As the dimensions of feature size have been scaled down (width and the thickness is reduced down to 50 urn and 2 urn or less), gate leakage current is increased and reliability of $SiO_2$ is reduced. Many metal oxides such as $TiO_2$, $Ta_2O_4$, $SrTiO_3$, $Al_2O_3$, $HfO_2$ and $ZrO_2$ have been challenged for memory devices. These materials posses relatively high dielectric constant, but $HfO_2$ and $Al_2O_3$ did not provide sufficient advantages over $SiO_2$ or $Si_3N_4$ because of reaction with Si substrate. Recently, $HfO_2$ have been attracted attention because Hf forms the most stable oxide with the highest heat of formation. In addition, Hf can reduce the native oxide layer by creating $HfO_2$. However, new gate oxide candidates must satisfy a standard CMOS process. In order to fabricate high density memories with small feature size, the plasma etch process should be developed by well understanding and optimizing plasma behaviors. Therefore, it is necessary that the etch behavior of $HfO_2$ and plasma parameters are systematically investigated as functions of process parameters including gas mixing ratio, rf power, pressure and temperature to determine the mechanism of plasma induced damage. However, there is few studies on the the etch mechanism and the surface reactions in $BCl_3$ based plasma to etch $HfO_2$ thin films. In this work, the samples of $HfO_2$ were prepared on Si wafer with using atomic layer deposition. In our previous work, the maximum etch rate of $BCl_3$/Ar were obtained 20% $BCl_3$/ 80% Ar. Over 20% $BCl_3$ addition, the etch rate of $HfO_2$ decreased. The etching rate of $HfO_2$ and selectivity of $HfO_2$ to Si were investigated with using in inductively coupled plasma etching system (ICP) and $BCl_3/Cl_2$/Ar plasma. The change of volume densities of radical and atoms were monitored with using optical emission spectroscopy analysis (OES). The variations of components of etched surfaces for $HfO_2$ was investigated with using x-ray photo electron spectroscopy (XPS). In order to investigate the accumulation of etch by products during etch process, the exposed surface of $HfO_2$ in $BCl_3/Cl_2$/Ar plasma was compared with surface of as-doped $HfO_2$ and all the surfaces of samples were examined with field emission scanning electron microscopy and atomic force microscope (AFM).

• Nuclear Engineering and Technology
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• v.51 no.5
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• pp.1345-1354
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• 2019

Clogging of sump strainers that filter the recirculation water in containment after a loss-of-coolant accident (LOCA) seriously impedes the continued cooling of nuclear reactor cores. In experiments examining the corrosion of aluminium alloy 6061, a common material in containment equipment, in borated solutions simulating the water chemistry of sump water after a LOCA, we found that Fe-bearing intermetallic particles, which were initially buried in the Al matrix, were progressively exposed as corrosion continued. Their cathodic nature $vis-{\grave{a}}-vis$ the Al matrix provoked continuous trenching around them until they were finally released into the test solution. Such particles released from Al alloy components in a reactor containment after a LOCA will be transported to the sump entrance with the recirculation flow and trapped by the debris bed that typically forms on the strainer surface, potentially aggravating strainer clogging. These Fe-bearing intermetallic particles, many of which had a rod or thin strip-like geometry, were identified to be mainly the cubic phase ${\alpha}_c-Al(Fe,Mn)Si$ with an average size of about $2.15{\mu}m$; 11.5 g of particles with a volume of about $3.2cm^3$ would be released with the dissolution of every 1 kg 6061 aluminium alloy.

• Journal of Periodontal and Implant Science
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• v.29 no.4
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• pp.913-928
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• 1999

Since their discovery in 1949, cyanoacrylates interest many people as possibly being the ideal "Tissue glue". Several different forms of these compounds have been developed in attempt to reduce or eliminate tissue toxicity. Butyl-2-cyanoacrylate(Histoacryl) appears to be the most ideal material as it induces low tissue reactivity & toxicity. In this study, the histotoxic response of histoacryl, when used in a subcutaneous site was compared to a controls which was conventionally sutured. This response was greater than the control that showed no inflammation. However, these findings may not corre-late in actual clinical settings, because most patients tolerate mild degrees of infla-mmation well. Majority of the studies evaluating the histotoxicity of histoacryl have been per-formed when applied superficially & not below the skin surface. This is why further studies are required to evaluate the his-totoxicity of histoacryl when used in a sub-cutaneous site or mucosa.

• Korean Institute of Interior Design Journal
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• v.19 no.6
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• pp.129-140
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• 2010

Malaysian traditional houses are basically post-and-beam structures raised on pillars, with gabled roofs. They were designed and built by the people themselves to meet specific needs, accommodating the values, economies and ways of life of cultures that produce them. The main purpose of this study is to understand the form and culture of Traditional houses in Malaysia through two parts. The first part is to summarize the general characteristic of traditional houses of Malaysia in the aspect of two different perspectives. One is the climate perspective, for which the analysis was made on the primary characteristics such as the climate, material, structure of the vernacular houses. The other one is the social-cultural perspective which try to find the religion, belief, life style and social and family relationship which controlled the forms of the housing under the surface. As a result, this study summarise and find the outstanding and unique meaning and definition of the traditional houses in Malaysia. The second part is to survey the specific case of the traditional house. Rumah Penghulu which were located in Kuala Lumpur were analyzed. As a result, this study summarise and find the formal and symbolic features of the traditional Malay houses. We hope that this study addresses the blank area in Korean housing studies about Southeast Asia countries which have not been clearly introduced yet.

• Journal of architectural history
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• v.8 no.4 s.21
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• pp.81-94
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• 1999

The purpose of this study is to interpret a house as material into culture. Main method is an ethnographic interview with dwellers as a part of a participant observation, a kind qualitative study. Significantly two different types of folk housing are discovered in East and West areas of the Cheju Island. In the East, kitchen itself forms a separated building, Jeongji-gori, whereas in the West, kitchen is within a main building, An-gori. Different type of kitchen is formed by the different family system. While independent family system of son and father selects a separate kitchen building as a general rule of Cheju Island, an extended family system between father and son selects same kitchen, Jeongji-gori, in the east area. Natural environment of infertile soil of east area makes family work together and eat together. Inner space of the kitchen building is utilized not only in cooking but also in eating, working, and sleeping. In order to explain folk house type, a 'culture area' concept is suggested. The interrelated 'cultural type' of architecture behind a physical surface 'type' is suggested as a new typology.

• Transactions on Electrical and Electronic Materials
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• v.1 no.2
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• pp.28-31
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• 2000

BaTiO$_3$cerameic thin films doped with Mn were manufactured by rf/dc magnetron sputter technique. We have investigated crystal structure, surface morphology and PRCR(positive-temperature coefficient of resistance) characteristics of the specimen depending on second heat-treatment temperature. Second heat treatment of the specimen were performed in the temperature range of 400 to 1350$\^{C}$ X-ray diffraction patterns of BaTiO$_3$ thin films show that the specimen heat treated below 600$\^{C}$ is an amorphous phase and the one heat treated above 1100$\^{C}$ forms a poly-crystallization . In this specimen heat-treated at 1300$\^{C}$, a lattice constant ratio(c/a) was 1.188. Scanning electron microscope(SEM) image of BaTiO$_3$ thin films of the specimen heat treated in between 900 and 1100$\^{C}$ shows a grain growth. At 1100$\^{C}$, the specimen stops grain-growing and becomes a poly-crystallization . A resistivity-temperature characteristics of the specimen depends on the doping concentrations of Mn. A resistivity ratio between the value at room temperature and the one above Curie temperature was 10$^4$ for pure BaTiO$_3$ thin films and 10$\^$5/ fo BaTiO$_3$ : additive 0.127mol% MnO

• Advances in nano research
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• v.14 no.4
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• pp.355-362
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• 2023

Physical exercise, especially intense exercise and high intensity interval training (HIIT) by trampoline, can lead to muscle injuries. These effects can be reduced with intelligent products made of nanocomposite materials. Most of these nanocomposites are polymers reinforced with silicon dioxide, alumina, and titanium dioxide nanoparticles. This study presents a polymer nanocomposite reinforced with silica. As a result of the rapid reaction between tetraethyl orthosilicate and ammonia in the presence of citric acid and other agents, silica nanostructures were synthesized. By substituting bis (4-amino phenoxy) phenyl-triptycene in N, N-dimethylformamide with potassium carbonate, followed by catalytic reduction with hydrazine and Pd/C, the diamine monomer bis (4-amino phenoxy) phenyl-triptycene is prepared. We synthesized a new polyaromatic (imide) with triptycene unit by sol-gel method from aromatic diamines and dianhydride using pyridine as a condensation reagent in NMP. PI readily dissolves in solvents and forms robust and tough polymer films in situ. The FTIR and NMR techniques were used to determine the effects of SiO₂ on the sol-gel process and the structure of the synthesized nanocomposites. By using a simultaneous thermal analysis (DTA-TG) method, the appropriate thermal operation temperature was also determined. Through SEM analysis, the structure, shape, size, and specific surface area of pores were determined. Analysis of XRD results is used to determine how SiO₂ affects the crystallization of phases and the activation energy of crystallization.

• Korean Journal of Soil Science and Fertilizer
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• v.20 no.4
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• pp.309-314
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• 1987

This study was conducted to examine mineralogical aspects on anthractite and bituminous coal-fired power-plant ashes as a source of mineral fertilizer. Fly ashes contain dominant amounts of silica and alumina and considerable quantitites of potassium and boron. However, potassium and silica present in unavailable forms for plant growth. X-ray, DTA, and IR analysis of ash particles indicated the formation of new mineral, mullite with shape of which were spherical in the surface morphologies of SEM. Detailed SEM investigation showed the presence of imbedded blocky shape silicate material.