We report the structural and antireflective characteristics of catalyst-free GaN nanostructures on GaN/sapphire template for solar cell applications. The formation of GaN nanostructure depends on the growth temperature. At 530 °C, the nucleation of the initial seed due to the enhanced strain leads to the hexagonal closely packed nanorods. As the growth temperature decreases, the depression of atomic Ga transport changes the films into nanocolumns, and then the nanorods. The catalyst-free GaN nanorods have wurtzite structure and good single crystalline quality. The GaN nanorods exhibit a remarkably low reflectance over a wide-angle broadband spectrum, enhancing the antireflective property of GaN surface.

In the directed energy deposition (DED) process, significant empirical testing is required to select the optimal process parameters. In this study, single-track experiments were conducted using laser power and scan speed as parameters in the DED process for titanium alloys. The results of the experiment confirmed that the deposited surface color appeared differently depending on the process parameters. Cross-sectional view, hardness, microstructure, and component analyses were performed according to the color data, and a color suitable for additive manufacturing was selected. Random forest (RF) and support vector machine multi-classification models were constructed by collecting surface color data from a titanium alloy deposited on a single track; the accuracies of the multi-classification models were compared. Validation experiments were performed under conditions that each model predicted differently. According to the results of the validation experiments, the RF multi-classification model was the most accurate.

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The Technology of Flatron CDT has been developed by LG Electronics. While we are developing the FLATRON, in spite of knowing that the flat screen CDT give many merits to PC(Personal Computer) and Workstation users, we find why conventional CDT have spherical and cylindrical face. One reason is that it is much more difficult to make glass in flat rather than spherical or cylindrical shapes. The other is a flat shadow mask expands or domes more severely by electrons than a rounded one. LG FLATRON conquered the difficulties by applying perfectly flat panel and using the flat tensioned mask. Also we can adopt interchange ability process in mask and faceplate. We will show how to accomplish innovational process which are NCE(Near Contact Exposure) and ICM (Interchangeable Mask) for Flatron CDT.

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