• The Transactions of the Korean Institute of Electrical Engineers C
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• v.52 no.10
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• pp.436-440
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• 2003

The (S $r_{0.85}$C $a_{0.15}$)Ti $O_3$(SCT) thin films were deposited on Pt-coated electrode(Pt/TiN/ $SiO_2$/Si) using RF sputtering method according to the deposition condition. The optimum conditions of RF power and Ar/ $O_2$ ratio were 140[W] and 80/20, respectively. Deposition rate of SCT thin films was about 18.75[$\AA$/min] at the optimum condition. The composition of SCT thin films deposited on Si substrate is close to stoichiometry (1.102 in A/B ratio). The capacitance characteristics had a stable value within $\pm$4[%]. The drastic decrease of dielectric constant and increase of dielectric loss in SCT thin films were observed above 200[kHz]. SCT thin films used in this study showed the phenomena of dielectric relaxation with the increase of frequency.ncy.

• JSTS:Journal of Semiconductor Technology and Science
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• v.9 no.1
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• pp.51-54
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• 2009

Transparent Cuprous oxide film was deposited by rapid thermal oxidation (RTO) of Cu at $500^{\circ}C$/45s condition on textured single-crystal n-Si substrate to form $Cu_2O$/n-Si heterojunction photodiode. The Hall effect measurements for the $Cu_2O$ films showed a p-type conductivity. The photovoltaic and electrical properties of the junction at room temperature were investigated without any post-deposition annealing. I-V characteristics revealed that the junction has good rectifying properties. The C-V data showed abrupt junction and a built-in potential of 1 V. The photodiode showed good stability and high responsivity in the visible at three regions; 525 nm, 625-700 nm, and 750nm denoted as regions A, B, and C, respectively.

• Journal of the Korean Solar Energy Society
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• v.39 no.4
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• pp.1-9
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• 2019

Modules using 6 inch cells have problems with loss due to empty space between cells. To solve this problem made by shingled structure which can generate more power by utilizing empty space by increasing the voltage level than modules made in 6inch cell. Thus, in this paper, the c-Si cutting cells were produced using nanosecond green laser, and then the ECA was sprayed and cured to perform cutting cell bonding. Three types of ECA materials (B1, B2, B3) with Ag as the main component were used, and experimental conditions varied from 5 to 120 seconds of curing time, 130 to $210^{\circ}C$ of curing temperature, and 1 to 3 of curing numbers. As a results of experiments varying curing time, B1 showed efficiency 19.88% in condition of 60 seconds, B2 showed efficiency 20.15% in 90 seconds, and B3 showed efficiency 20.27% in 60 seconds. In addition, experiments with varying curing temperature, It was confirmed highest efficiency that 20.04% in condition of $170^{\circ}C$ with B1, 20.15% in condition of $150^{\circ}C$ with B2, 20.27% in condition of $150^{\circ}C$ with B3. These are because the Ag particles are densely formed on the surface to make the conduction path. After optimizing the conditions of temperature and curing time, the secondary-tertiary curing experiments were carried out. as the structural analysis, conditions of secondary-tertiary curing showed cracks that due to damp heat aging. As a result, it was found that the ECA B3 had the highest efficiency of 20.27% in condition of 60 seconds of curing time, $150^{\circ}C$ of curing temperature, and single number of curing, and that it was suitable for the manufacture of Solar cell of shingled structure rather than ECA B1 and B2 materials.

• Advances in nano research
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• v.12 no.2
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• pp.213-221
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• 2022

Silicon carbide (SiC) is a binary carbon-silicon compound. In its two-dimensional form, monolayer SiC is composed of a monolayer carbon and silicon atoms constructed as a honeycomb lattice. SiC has recently been receiving increasing attention from researchers owing to its intriguing electronic properties. In this present work, SiC nanoribbons (SiCNRs) are modelled and simulated to obtain accurate electronic properties, which can further guide fabrication processes, through bandgap engineering. The primary objective of this work is to obtain the electronic properties of monolayer SiCNRs by applying numerical computation methods using nearest-neighbour tight-binding models. Hamiltonian operator discretization and approximation of plane wave are assumed for the models and simulation by applying the basis function. The computed electronic properties include the band structures and density of states of monolayer SiCNRs of varying width. Furthermore, the properties are compared with those of graphene nanoribbons. The bandgap of ASiCNR as a function of width are also benchmarked with published DFT-GW and DFT-GGA data. Our nearest neighbour tight-binding (NNTB) model predicted data closer to the calculations based on the standard DFT-GGA and underestimated the bandgap values projected from DFT-GW, which takes in account the exchange-correlation energy of many-body effects.

• Proceedings of the Korean Magnestics Society Conference
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• 2005.06a
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• pp.146-147
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• 2005

• Journal of the Korean Ceramic Society
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• v.23 no.2
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• pp.13-20
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• 1986

Composite polycrystals including ${\gamma}$-$6Bi_2O_3$.$SiO_2$ crystal which have needlelike regular structure are useful for the high resolution optical devices. For the purpose of obtaining the composite polycrystals described above the melts of eutectic composition in the three eutectic systems including $6Bi_2O_3$.$SiO_2$ composition were unidirectionally solidified at a rate of 0.05 and 0.25 cm/h under a thermal gradient of 10$0^{\circ}C$/m. Composite polycrystals of relatively regular structure in which needlelike ${\gamma}$-$6Bi_2O_3$.$SiO_2$ crystals were arrayed in parallel with $2Bi_2O_3$.$B_2O_3$ crystal matrix were obtained when the eutectic melt of $6Bi_2O_3$.$SiO_2 -2Bi_2O_3$.$B_2O_3$ system was solidified at a rate of 0.25 cm/h. Partial structural irregularity however was found in the obtained composite polycrystals.

• Journal of the Korean Magnetics Society
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• v.10 no.2
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• pp.49-52
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• 2000

The changes of magnetic properties in neutron irradiated F $e_{81}$ $B_{13.5}$S $i_{3.5}$ $C_2$ amorphous ribbon were studied by X-ray diffraction, hysteresis loop, temperature dependence of magnetization and complex permeability. The fluences of thermal ( $n_{th}$) and fast ( $n_{f}$) neutron were 6.95$\times$10$^{18}$ $n_{th}$ c $m^{-2}$ and 4.56$\times$10$^{16}$ $n_{f}$c $m^{-2}$ , respectively. The changes of XRD Profiles were not observable at the neutron irradiated sample. The complex permeability spectra showed that the permeability from domain wall motion decreased due to the increase of pinning force against domain motion by the neutron irradiation, and the relaxation frequency of rotational magnetization moved to higher frequency region. The measurement of hysteresis loop showed the increase of magnetic softness, related to rotational magnetization, but saturation magnetization was decreased in neutron irradiation sample. The Curie temperature was decreased in the neutron irradiated sample.e.e.e.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.802-805
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• 2000

Anistropic [Ta/NdFeB/Ta] thin film was sputtered on heated Si substrate by Nd$\_$17/Fe$\_$74/B$\_$9/ target. The grain size of the films increased according to the increase of substrate temperature, and the film deposited at 650$^{\circ}C$ showed optimum coercivity. 4$\pi$M$\_$r/, $\_$i/H$\_$c/ and (BH)$\_$max/ measured perpendicular to the film plane of thin film deposited at 650$^{\circ}C$ are 12.3 kG, 9.9 kOe and 37 MGOe, respectivly.

• Composites Research
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• v.30 no.2
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• pp.116-125
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• 2017

The purpose of this study is to develop silicon carbide fiber showing an excellent mechanical properties under highly oxidative conditions at high temperature. Polycarbosilane(PCS) as a preceramic precursor was used for making the SiC fiber. PCS fiber was taken by melt spinning method followed by melting the PCS at $300{\sim}350^{\circ}C$ in N2 gas. The Curing of PCS fiber was carried out in air oxygen chamber, prior to high temperature pyrolysis. Degree of cure was calculated by characteristic peak's ratio of Si-H to $Si-CH_3$ in FT-IR spectra before and after curing of PCS fiber. The properties of SiC fiber was affected greatly by the degree of cure. The SiC fiber produced by controlling fiber tension during heat treatment showed good properties. The SiC fiber exposed to $1000^{\circ}C$ at air from 1 min. up to maximum 50 hrs showed around 60% reduction in tensile strength. We found that large amount of carbon content on the fiber surface after long-term exposure has resulted in lower tensile strength.

• Korean Journal of Metals and Materials
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• v.48 no.1
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• pp.28-38
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• 2010

High temperature high cycle and low cycle fatigue deformation behavior of automotive heat resistant aluminum alloys (A356 and A319 based) were investigated in this study. The microstructures of both alloys were composed of primary Al-Si dendrite and eutectic Si phase. However, the size and distribution for eutectic Si phase varied: a coarse and inhomogeneous distributed was observed in alloy B (A319 based). A brittle intermethallic phase of ${\alpha}-Fe\;Al_{12}(Fe,Mn)_3Si_2$ was detected only in B alloy. Alloy B exhibited high fatigue life only under a high stress amplitued condition in the high cycle fatigue results, whereas alloy A showed high fatigue life when stress was lowered. With regard to the low-cycle fatigue result ($250^{\circ}C$) showing higher fatigue life as ductility increased, alloy A demonstrated higher fatigue life under all of the strain amplitude conditions. Fractographic observations showed that large porosities and pores near the outside surface could be the main factor in the formation of fatigue cracks. In alloy B. micro-cracks were formed in both the brittle intermetallic and coarse Si phasese. These micro-cracks then coalesced together and provided a path for fatigue crack propagation. From the observation of the differences in microstructure and fractography of these two automotive alloys, the authors attempt to explain the high-temperature fatigue deformation behavior of heat resistant aluminum alloys.