• The Transactions of the Korean Institute of Electrical Engineers D
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• v.53 no.4
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• pp.226-234
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• 2004

A rapid Prototyping system that laser-cuts and laminates thick layers can fabricate 3D objects promptly with a variety of materials. Building such a system must consider the surface distortions due to both vertical-cut layers and triangular surfaces. We developed a tangential layer-cutting algorithm by rearranging tangential lines such that they reconstruct 3D surfaces more closely and also constitute smoother laser trajectories. An energy function that reflects the surface-closeness with the tangential lines was formulated and then the energy was minimized by a gradient descent method. Since this simple method tends to cause many local minima for complex 3D objects, we tried to solve this problem by adding a simulated annealing process to the proposed method. To view and manipulate 3D objects, we also implemented a 3D visual environment. Under this environment, experiments on various 3D objects showed that our algorithm effectively approximates 3D surfaces and makes laser-trajectory feasibly smooth.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.574-577
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• 2001

GaN thin films on sapphire were grown by rf magnetron sputtering with ZnO buffer layer. The dependence of GaN film quality on ZnO buffer layer was investigated by X-ray diffraction(XRD). The improved film quality has been obtained by using thin ZnO buffer layer. Using Auger electron spectroscopy(AES), it was observed that the annealing process improved the GaN film quality. The surface roughness according to the annealing temperatures(700, 900, 1100$^{\circ}C$) were investigated by AFM(atomic force microscopy) and it was confirmed that the crystallization was improved by increasing the annealing temperature. Photoluminescence at 8K shows a near-band-edge peak at 3.2eV with no deep level emission.

• Journal of the Korean Institute of Telematics and Electronics
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• v.25 no.8
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• pp.950-958
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• 1988

We have implemented a RTA system using W-halogen lamps and tried to recrystallize the phosphorus ion implanted amorphous silicon on insultor (SOI) taking advantages of seeding window. The purpose of this study is to investigate the possibility of a typical crystalline orientation occurred during the solidifying process of molten amorphous silicon layer. Experimental results show that several twin boundaries are found on the seeding window region after annealing for 15 sec at 1040\ulcorner. These twin boundaries represent that the recrystallization is partialy possible and when the annealing is done at 1150\ulcorner, (100) etch pits with <110> facets are found on the solidified amorphous silicon layer. Consequently, Hall mobility of recrystallized silicon film is measured and the thermal behavior of grain boundary is also observed by SEM.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.4
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• pp.855-868
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• 1996

In this paper, multiplhase only filter(MPOFs) are designed using simulated annealing algorithm. These filters have excellent recognition characteristics for similar patterns or rotated patterns and enhance optical efficiency as well as spatial-bandwidth product by deleting mirror image. As the result of computer simulation to certify recogntion characteristics of similar patterns, simulated annealing-MPOF(SA-MPOF) has superior discrimination and higher correlation peak values than cosine binary phase only filters(CBPOF) and simpulated annealing-BPOF (SA-BPOF). THe filter having training process for rotated patterns of arbitraty possible angle can overcome that phase only filter(POF) and CBPOF can't recognize rotated input patterns.

• Proceedings of the IEEK Conference
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• 2001.06b
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• pp.209-212
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• 2001

High quality Taros thin films have been obtained from anodizing. The as-deposited amorphous films have excellent physical and electrical properties: refractive indices ~2.15, dielectric constants ~25, and leakage currents <10$^{-8}$ Ac $m^{-2}$ at 1MV $cm^{-1}$ , 700$\AA$ thickness. We fabricated a MIM element with theses T $a_2$ $O_{5}$ films which had perfect current-voltage symmetry characteristics using a new process technology which was post annealing of whole MIM element instead of conventional annealing conditions (top-electrode metals, annealing conditions) on the capacitor performances were extensively discussed throughout this work.k.

• Journal of Integrative Natural Science
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• v.9 no.4
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• pp.275-280
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• 2016

Intensity modulated photovoltage spectroscopy (IMVS) analysis of organic solar cells (OSCs) with a bulk-heterojunction (BHJ) film composed of P3HT and $PC_{61}BM$ was performed. The dynamic response of charge recombination by the post-annealing approach in $P3HT/PC_{61}BM$ BHJ solar cells characterized by IMVS demonstrated that post-annealing reduced the recombination of electron carriers in the device. The recombination times of $P3HT/PC_{61}BM$ BHJ solar cells post-annealed at room temperature, 80, 120, and $140^{\circ}C$ were 0.009, 0.020, 0.024, and 0.030 ms, respectively, at a short-circuit current of 0.18 mA. The results indicated that the IMVS analysis can be effectively used as powerful.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2000.04a
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• pp.202-205
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• 2000

The effect of two step cold rolling and intermediate annealing conditions on the microstructure and texture evolution in type 430 stainless steel has been investigated tin order to improve ridging characteristic and deep drawability. The rolling and recrystallization textures were examined by orientation distributionfunction(ODF) and electron backscattered diffraction(EBSD). The observation showed that the intensity of ${\gamma}$-fiber was increased with two-step cold rolling process and so ridging characteristic and deep drawability were considerably improved. The relation between these properties an texture evolution has been discussed.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.1810-1815
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• 2003

Tube hydroforming provides a number of advantages over conventional stamping process, including fewer secondary operation, weight reduction, assembly simplification, adaptability to forming of complex structural components and improved structural strength and stiffness. In this study, the effect of the heat treatment on the hydro-formability has been investigated. By using the mild steel tube bulging test is performed at various heat treatment conditions to evaluate the hydro-formability.

• Progress in Superconductivity
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• v.3 no.2
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• pp.168-171
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• 2002

We have demonstrated ramp-edge Josephson junctions using high temperature superconductors without depositing artificial barriers. We fabricated a surface barrier formed naturally during an ion beam etching process and the annealing under the oxygen atmosphere. The experimental results imply that the barrier natures such as the resistivity are varied by the annealing conditions and the ion milling conditions including the beam voltages. Thus, the ann eating and etching conditions should be optimized to obtain excellent junction properties. In optimizing the fabricating factors, the interface-controlled junctions showed resistively shunted junctions like current-voltage characteristics and an excellent uniformity. These junctions exhibited a spread ($1\sigma$) of $I_{c}$ is 10% fur chips containing 7 junctions at 50K.K.

• Journal of the Korean Vacuum Society
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• v.1 no.1
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• pp.168-175
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• 1992

The surface and interface morphology as well as the sheet resistance, and uniformity of TiSiz film are significantly improved and the lateral titanium silicide growth over the oxide spacer is minimized by the use of ion beam mixing and rapid thermal annealing in nitrogen ambient. In addition, TiSiz film formations on TiISi and TiISiOz system were also studied.