• Applied Microscopy
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• v.48 no.4
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• pp.130-131
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• 2018

Electron channeling contrast imaging (ECCI) is one of the imaging techniques in scanning electron microscopy based on a variation in electron backscattering yield depending on the direction of the primary electron beam with respect to the crystal lattice. The ECCI provides not only observation of the distribution of individual grains and grain boundaries but also identification of the defects such as dislocations, twins, and stacking faults. The ECCI at the interface between recrystallized and deformed region of shot peening treated nickel clearly demonstrates the microstructural evolution during the recrystallization including original grain boundaries, and thus can provide better insight into the recrystallization behavior.

• Applied Microscopy
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• v.46 no.4
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• pp.238-243
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• 2016

Twinning-induced plasticity (TWIP) steels with the austenite structure containing high manganese exhibit both good strength and excellent formability. Such properties originate from crystallographic slip and mechanical twins produced when the austenite structure is under mechanical stress. There are 12 twin systems, referred to as twin variants, when slip is induced. These twin systems include twin planes and twin directions and play an important role in determining strength and ductility of the material by strongly influencing texture formation of the austenite structure. In the present study, twins produced in a high-Mn TWIP steel as a result of uniaxial tension were observed using a transmission electron microscope; a comparative analysis was performed through interaction energy calculations. Electron diffraction was used to determine the twin system with respect to the uniaxial tension direction in each grain. Both the Schmid factors and interacting energies required for the generation of twins were calculated and subsequently compared with experimental results. This approach demonstrated the possibility of predicting the deformation behavior of the material.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2006.11a
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• pp.366-369
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• 2006

Multi Housing design has not considered the remodeling even at the beginning of the construction. This severely hindered systematic maintenance, providing fundamental causes of consuming society. In general, in about 20 years when the buildings become too old, they are brought down or removed with a trail of waste left behind. In addition, since the current remodeling or future remodeling type is a general remodeling that leaves only a frame, some question the role of the remodeling as a solution to the reconstruction from economically and environmentally efficient aspects. This study intends to find a solution for long-life span multi-family housing design, promoting sequential remodeling by stating the life cycle of components. Problems were identified by analyzing joints, design and construction of multi-family housing based on the previous researches. Conclusion from characterization of the design plan according to joint parts can be summarized as the following firstly, the problem of the wet was seen in joints between the structure and a finishing materials and ones between separate finishing materials. Secondly, the problem of overlap was frequently seen in joints between the structure and a door/window, ones between a door/window and a finishing materials, and ones between a finishing materials and an electrical/mechanical device.

• Applied Biological Chemistry
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• v.36 no.5
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• pp.358-363
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• 1993

The metabolic capability of the cultured cells of peppermint was tested with whole intact cells by feeding appropriate exogenous substrates to the suspension cultures. Conversion of (-)-limonene into any other monoterpenes was not observed with the suspension cultures. (+)-Pulegone was converted into (+)-isomenthone and (-)-menthone, and (-)-menthone into (-)-menthol. The experiments confirmed that the suspension retained most of the menthol biosynthesis pathway in the cell except for a few loci. (-)-Isopiperitenone was transformed into (+)-pulegone, piperitenone, (-)-7-hydroxyisopiperitenone and two unidentified products.

• Journal of the Korean Ceramic Society
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• v.40 no.4
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• pp.393-397
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• 2003

To investigate the effect of AIN c-axis orientation on the resonance performance of film bulk acoustic wave resonators, solidly mounted resonators with crybtallographically different AIN piezoelectric films were prepared by changing only the bottom electrode surface conditions. As increasing the degree of c-axis texturing, the effective electromechanical coupling coefficient ($\kappa$$\_$eff/)$^2$ in resonators increased gradually. The least 4 degree of full width at half maximum in an AIN(002) rocking curve, which corresponds to $\kappa$$^2$$\_$eff/ of above 5%, was measured to be necessary for band pass filter applications in wireless communication system. The longitudinal acoustic wave velocity of AIN films varied with the degree of c-axis texturing. The velocity of highly c-axis textured AIN film was extracted to be about 10200 n/s by mathematical analysis using Matlab.

• Applied Microscopy
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• v.42 no.3
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• pp.174-178
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• 2012

In the present study, the oxidation behavior of $Cu_{50}Zr_{50}$ and $Cu_{46}Zr_{46}Al_8$ metallic glasses has been investigated using transmission electron microscopy with a particular attention on the oxidation behavior in the supercooled liquid state. Identification of the oxidation product after continuous heating treatment shows that in $Cu_{50}Zr_{50}$ metallic glass, $ZrO_2$ with the monoclinic structure forms on the supercooled liquid as well as on the crystallized matrix. On the contrary, in $Cu_{46}Zr_{46}Al_8$ metallic glass, $ZrO_2$ with the tetragonal structure forms on the supercooled liquid, but that with the monoclinic structure forms on the crystallized matrix. The result indicates that the $Cu_{50}Zr_{50}$ metallic glass exhibits far better oxidation resistance in the supercooled liquid state than the $Cu_{46}Zr_{46}Al_8$ metallic glass.

• Journal of the Korea Safety Management & Science
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• v.17 no.1
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• pp.257-264
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• 2015

"Act on Facilitation of Purchase of Small and Medium Enterprise - Manufactured Products and Support for Development of Their Markets" was created and implemented. The act states that the materials designated by the Small and Medium Business Administration are directly purchased from the small and medium enterprises and provided to the construction companies so that the materials can be provided as GFGI (Government Furnished and Government Installed) in the case of a public construction project. This thesis is aimed to analyze the current status on the problems of each project party and understand their improvement requests so that mutually beneficial plans can be sought and improved process is presented for the continuous development of the direct construction material purchase system as well as successful construction projects. And This thesis summarized the purpose of the institutions and their change histories, and related law as well as codes for the better understanding of administrative procedures for the purchase system and the analyses as well as the improved process on the difficulties in complying with the current institutions.

• Applied Microscopy
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• v.43 no.4
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• pp.173-176
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• 2013

The oxidation behavior of the crystallized $Al_{87}Ni_3Y_{10}$ alloy has been investigated with an aim to compare with that of the amorphous $Al_{87}Ni_3Y_{10}$ alloy. The oxidation at 873 K occurs as follows: (1) growth of an amorphous aluminum-yttrium oxide layer (~10 nm) after heating up to 873 K; and (2) formation of $YAlO_3$ crystalline oxide (~220 nm) after annealing for 30 hours at 873 K. Such an overall oxidation step indicates that the oxidation behavior in the crystallized $Al_{87}Ni_3Y_{10}$ alloy occurs in the same way as in the amorphous $Al_{87}Ni_3Y_{10}$ alloy. The simultaneous presence of aluminum and yttrium in the oxide layer significantly enhances the thermal stability of the amorphous structure in the oxide phase. Since the structure of aluminum-yttrium oxide is dense due to the large difference in ionic radius between aluminum and yttrium ions, the diffusion of oxygen ion through the amorphous oxide layer is limited thus stabilizing the amorphous structure of the oxide phase.

• Applied Microscopy
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• v.48 no.3
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• pp.73-80
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• 2018

Ductile cast iron is widely used for many automotive components due to its high wear resistance and fatigue resistance in addition to the low cost of fabrication. The improvement of wear resistance and fatigue properties is key to the life time extension and performance increase of the automobile parts. Surface nanocrystallization is a very efficient way of improving the performance of materials including the wear- and fatigue-resistance. Shot peening treatment, as one of the popular and economic surface modification methods, has been widely applied to various materials. In this study, ductile cast iron specimens were ultrasonic shot peening (USP) treated for 5 to 30 min using different ball size. The microstructures were then microscopically analyzed for determination of the microstructural evolution. After the USP treatment, the hardness of pearlite and ferrite increased, in which ball size is more effective than treatment time. With USP treatment, the graphite nodule count near the surface was decreased with grain refinement. The lager balls resulted in an increased deformation, whereas the smaller balls induced more homogenously refined grains in the deformation layer. In addition, formation of nanoparticles was formed in the surface layer upon USP.

• Journal of Conservation Science
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• v.6 no.1 s.7
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• pp.71-78
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• 1997

Oil painting shows a wide variety of damages due to differentcohesiveness between materials and different responses to temperature and humidity. The deforming flatness of canvas is a major cause of deterioration. The heat, pressure and moisture, and classical materials which had been traditionally used to correct the deformation of supports have caused damages to the paintings. In modern restoration of paintings, new methods have been developed to avoid the use of such potentially harmful elements. In this paper the correcting of deformed support with the use of low-pressure table, deformation correction frame and new materials, which has been developed both to protect the works and to maximize the effect of restoration.