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As NPPs continue to operate, liquid waste continues to be generated, and containers are needed to store and transport them at low cost and high capacity. To transport and store liquid phase very low-level radioactive waste (VLLW), a container is designed by considering related regulations. The design was constructed based on the existing container design, which easily transports and stores liquid waste. The radiation shielding calculation was performed according to the composition change of barium sulfate (BaSO4) using the Monte Carlo N-Particle (MCNP) code. High-density polyethylene (HDPE) without mixing the additional BaSO4, represented the maximum dose of 1.03 mSv/hr (

Microelectrodes are widely used for neural signal analysis because they can record high-resolution signals. In general, the smaller the size of the microelectrode for obtaining a high-resolution signal, the higher the impedance and noise value of the electrodes. Therefore, to improve the signal-to-noise ratio (SNR) of neural signals, it is important to develop microelectrodes with low impedance and noise. In this research, an Au hierarchical nanostructure (AHN) was deposited to improve the electrochemical surface area (ECSA) of a microelectrode. Au nanostructures on different scales were deposited on the electrode surface in a hierarchical structure using an electrochemical deposition method. The AHN-modified microelectrode exhibited an average of 80% improvement in impedance compared to a bare microelectrode. Through electrochemical impedance spectroscopy analysis and impedance equivalent circuit modeling, the increase in the ECSA due to the AHN was confirmed. After evaluating the cell cytotoxicity of the AHN-modified microelectrode through an in vitro test, neural signals from rats were obtained in in vivo experiments. The AHN-modified microelectrode exhibited an approximate 9.79 dB improvement in SNR compared to the bare microelectrode. This surface modification technology is a post-treatment strategy used for existing fabricated electrodes, so it can be applied to microelectrode arrays and nerve electrodes made from various structures and materials.

Flexible transparent film heaters (FTHs) are used in a variety of applications, including smart windows and wearable devices, because they are transparent to visible light while generating Joule heat. FTHs are designed for high transparency and conductivity, with thermal stability and mechanical durability as secondary requirements. In general, there is a trade-off between transparency and conductivity, such that both factors must be optimized simultaneously to maximize performance. In this study, a conductive nanofiber network was fabricated on a flexible substrate via electrospinning. Copper (Cu) heaters were materialized on the nanofiber network via electroless deposition. Overlap between nanofibers was removed by heat treatment, resulting in a junction-free Cu nanofiber network without contact resistance. The properties of these FTHs could be actively controlled by optimizing the electrospinning and electroless deposition times, yielding a transparency of more than 90% and sheet resistance (RS) of several Ω/sq. As heaters, the optimized FTHs exhibited a uniform temperature distribution over their entire area, even when an external force was applied. The FTH fabrication method developed herein was based on direct electrospinning patterning and did not require any lift-off or transfer processes, which can result in defects. In addition, since electroless deposition has a low process complexity, it can be used in large-area processes and easily extended to fundamental technologies in various fields.

Oblique submicron-scale structures are used in various aspects of research, such as the directional characteristics of dry adhesives and wettability. Although deposition, etching, and lithography techniques are applied to fabricate oblique submicron-scale structures, these approaches have the problem of the controllability or throughput of the structures. Here, we propose a simple X-ray-lithography method, which can control the oblique angle of submicron-scale structures with areas on the centimeter scale. An X-ray mask was fabricated by gold film deposition on slanted structures. Using this mask, oblique ZEP520A photoresist structures with slopes of 20° and 10° and widths of 510 nm and 345 nm were fabricated by oblique X-ray exposure, and the possibility of polydimethylsiloxane (PDMS) molding was also confirmed. In addition, through double exposure with submicron- and micron-scale X-ray masks, dotted-line patterns were produced as an example of multiscale patterning.