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A metallurgical model for the prediction of bainite transformation behaviors at coarsened grain heat affected zone(CGHAZ) was proposed. The isothermal transformation kinetics for the bainite which does not include incubation time was described by Johnson-Mehl-Avrami(JMA) equation and the $quot;ideal TTT$quot; diagram which depends only on the materials considered and characterizes the transformation independently of the experiment`s condition was introduced to predict the onset of transformation during continuous cooling conditions. And effects of prior austenite grain size on kinetic parameters of JMA equation were examined by isothermal transformation experiments. It was observed that the reaction rate was accelerated by increasing the grain size. Coupling Scheil`s rule of additivity, the model for predicting the volume fraction of bainite and hardness was developed. The reliability of the developed model was discussed by comparing the predicted data with measured one.

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Annealing of a Fe-3.2%Si sheet having the primary recrystallized texture was performed with and without a high magnetic field in order to clarify the effect of magnetic field on microstructure orientation. Experimental parameters were heating rates(5, 15℃/min), annealing temperatures(700, 800, 1,000℃) and cold-rolling rate(70%). Magnetic field(5 T) was applied in a direction parallel to the rolling direction. Distributions of orientation and misorientation of secondary recrystallization grains were characterized with ODF and EBSP analyses. Magnetic field annealing was found to enhance the selectivity of {001} axis alignment and to suppress {111} axis orientation in the secondary recrystallized microstructure. The effectiveness of magnetic field annealing was more predominant in the condition of a lower annealing temperature of 800℃ and a higher heating rate of 15℃/min and deformation. However, the effect of magnetic field annealing was almost disappeared when annealed at 1,000℃, even in the cold-rolled sheet. It was also found that magnetic field annealing promoted the formation of high angle boundary having 45° grain orientation and CLS grains in secondary recrystallization texture. As a cause of selective formation of {100} texture in secondary recrystallization, magnetostriction induced by applying a magnetic field is suggested.

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The effects of annealing condition and temperature gradient on the crystallization of amorphous silicon (a-Si) were investigated by metal-induced lateral crystallization (MILC). We performed poet annealing of a-Si using conventional rapid thermal annealing (RTA) and scan-type RTA. We found that the scan-type RTA was more favorable in term of growth rate than the conventional RTA. With the temperature profile, we carried out the theoretical calculation of the MILC length using the Arrhenius model and compared with the experimental value. Also, we found that there were clear temperature gradient effects on the crystallization of a-Si. Mosaic patterns of Ni on top of the a-Si enable us to measure the effects of temperature gradient, that is, positive and negative gradient, on the crystallization of a-Si. As a result, a-Si with positive temperature gradient was crystallized faster than that of with negative temperature gradient.

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We have investigated the magnetic properties of α-Fe and Fe_(21)Ni_(79) nanowires, respectively fabricated by ac electroforming into templates consisting of nano-porous anodic aluminum oxide (AAO). α-Fe nanowires with various aspect ratios in the range of 300 to 1000 were found to be available to fabricate by engineering parameters of anodization such as temperature, time and voltage. Nanowire arrays of α-Fe and Fe_(21)Ni_(79) in AAO have been observed to show perpendicular magnetic anisotropy (PMA) via vibrating sample magnetometry (VSM), which is attributed to very high aspect ratio.

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Effect of grain orientation on the electrical polarization and leakage current characteristics of Bi_(3.25)La_(0.75)Ti₃O_(12) (BLT) thin films was investigated in terms of c-axis off alignment. The c-axis epitaxial and various c-axis off aligned BLT films have been successfully grown by using different electrode materials (Pt and SrRuO₃) and heat-treatments. In order to evaluate the crystallinity and the film texture of various c-axis off-aligned BLT thin films, X-ray diffraction (XRD) and transmission electron microscopy (TEM) were carried out. BLT thin film grown on the SrRuO₃/SrTiO₃ (100) substrate revealed that its c-axis aligned completely parallel to the substrate normal, by developing cube-on-cube epitaxial relathionship with underlying SrRuO₃ film. The corresponding P-E curve showed nearly paraelectric property. The polycrystalline (117) and (014) oriented BLT films grown in this study were shown that their c-axis off alignment about growth direction increased by amount more than 50°. As the degree of c-axis off-alignment was increased, remanent polarization was increased due to the anisotropic polarization characteristic of BLT film, however, the surface roughness of BLT films was increased and it resulted in degraded leakage current characteristic. Therefore, grain orientation of BLT thin films is a crucial factor controlling the polarization properties and leakage current characteristics.

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In order to evaluate the anisotropic magnetic properties of steel sheets, analytical expressions based on the orientation distribution function of samples were proposed and compared with experimental data in a Fe-3%Si single crystal. The magnetic anisotropy was measured by means of vibrating sample magnetometer(VSM) and the orientation was determined by X-ray texture goniometer. Anisotropy of the magnetic properties is found to be dependent on the magnetization energy which varies as a function of the crystallographical direction. Applying the measured magnetic properties to the analytical expressions, the anisotropy constants of K₄= 36500 J/㎥ and K_6 = 1000 J/㎥ were calculated. The highest magnetic permeability and flux density were obtained in the easy magnetization direction of [100]. The orientation independent magnetization energy of the Fe-3%Si single crystal was 16330 J/㎥.

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Thin Semi-transparent Cu films were deposited at room temperature, using rf-sputtering on porous silicon (PS). The porous layer with the thickness of about 15-17 ㎛ were obtained on p-type (100) silicon wafers, by applying various current densities viz. 25, 45, 65 and 85 ㎃/㎠. Various thicknesses of Cu films ranging from 45 to 170 Å were obtained by varying sputtering time. The red shift from 620 to 750 ㎚ was observed in PL peaks for the copper deposited PS. To analyze the surface morphology of the films scanning electron microscopy (SEM) and atomic force microscopy (AFM) analyses of the films were carried out. The surface roughness of Cu films as measured from AFM varies from 0.669 to 1.8575 ㎚. The refractive index of the films measured by ellipsometry, varies from 1.38 to 1.95 with increasing Cu film thickness. The I-V characteristics show the shift of the barrier from 0.65 to 0.77 eV with decreasing the etching current density from 85 to 25 ㎃/㎠.

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The shear strength and creep properties of Sn-57 wt.%Bi/Cu and Sn-57 wt.%Bi-0.5 wt.%Zn/Cu joints were studied. Modified double lap shear solder joints were aged for 60 days at 80℃ and then loaded to failure in shear. The shear strength of solder/Cu joints was decreased with aging treatment and the rapid decrease in shear strength of the Sn-57 wt.%Bi/Cu joint was appeared in the 60 days aged specimen. The crack path of aged solder/Cu joint were changed from through the solder to through the interface between Cu substrate and reaction layer with Zn addition. But the crack path under creep test was through the solder regardless of Zn addition.

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Effects of texture on formability and Baring of the strip cast 1050 Al alloy sheets were investigated using the continuous confined strip shearing (C2S2) process based on continuous equal channel angular pressing (ECAP). Subsequent heat treatment was conducted to control textures of the strips produced by ECAP. The texture evolutions due to ECAP and the subsequent heat treatment were studied using the measured pole figures and the calculated ODFs. The △r-value and d r￣- value were determined from the measured pole figures to judge the formability and the earing of the specimens. The production of the 1050 Al alloy sheets with high formability (r￣ =1.05) and low earing (△r = 0.05) could be possible by ECAP and the subsequent heat treatment at 350℃.

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