This study examines the efficiency of chitosan microbeads in manufacturing and their effectiveness as a disinfectant. The microbeads are developed using a solvent-assisted extraction process. The manufacturing process involves crosslinking chitosan through an emulsion-based method, with the help of a crosslinker. This leads to an increase in particle size while maintaining homogeneity and dispersion. The solvent-assisted method, which utilizes acetone, effectively extracts the crosslinked beads into the aqueous phase. This extraction process ensures the structural stability of the beads, with an average particle size of 40±3.94 ㎛. By incorporating the disinfectant agent into the chitosan beads, antiviral effects against the Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) were observed. These effects were found to be effective at dilutions estimated to be between 1 : 1 and 1 : 100. The findings of this study demonstrate the inherent antiviral capabilities of chitosan beads and the enhanced impact when combined with the disinfectant. This suggests a synergistic approach to managing viral infections in livestock environments.

With the progress of flexible devices, numerous researchers aim to manufacture the flexible battery with freefrom at various scales. Laser cutting is considered as one of the essential processes to achieve on-demand manufacturing but continuous wave or long-pulse laser beam may cause large heat affect zone (HAZ) in cutting edge and may even result in failure of battery function. Herein, it was demonstrated that the sophisticated cutting process using ultra-short pulse laser is applicable for tailoring of flexible battery with multilayered structure. Based on the comparison of cutting results using nanosecond laser and femtosecond laser, we confirmed that laser cutting by femtosecond laser induces much less thermal damage on thin foil electrodes, separator, and electrolyte. Furthermore, we investigated the interaction of femtosecond laser with the materials composed of a flexible battery and implemented a process for cutting each material without causing any critical damage. To prevent a short circuit between the anode and cathode, which usually occurs during laser cutting of the actual battery, the double-side cutting process was done by adjusting the focal points of the laser beam. We assume that the proposed approach can be applied in a roll-to-roll based cutting process for the mass-production of flexible devices.

Electrical isolation of Ag nanowire, which is one of the candidates as electrode for display devices, on polymer with femtosecond pulse laser has been investigated. Line patterning to Ag nanowire with various pulse energy and scan speed were experimented. Duo to the results of the line patterning experiment, we fabricated the isolated squares and measured electrical resistance. The profile of the selectively ablated area was analyzed with AFM(Atomic Force Microscope). The width of the patterned line was 1.8 ㎛ and the depth was 1.6 ㎛. We demonstrated electrical isolation of the Ag nanowire using femtosecond laser by evaluating the electrical resistance of the sample between isolated and opened area.

Transparent materials are widely used in the fields of optic parts and bio industry. We have experiment to find out the characteristics of the micro machining inside transparent materials using femtosecond laser pulses. With its non-linear effects by very high peak intensity, filament (plasma channel) was formed by the cause of the self-focusing and the self-defocusing. Physical damage could be found when the intensity is high enough to give rise to the thermal stress or evaporation. At the vicinity of the power which makes the visible damage or modification, the structural modification occurs with the slow scanning speed. According to the polarization direction to the scanning direction, the filament quality is quite different. There is a good quality when the polarization direction is parallel to the scanning direction. For fine filament, we could suggest the conditions of the high numerical aperture lens, the short shift of focusing point, the low scanning speed and the low power below 20 ㎽. As the examples of optics parts, we fabricated the fresnel zone plate with the 225 ㎛ diameter and Y-bend optical wave guide with the 5㎛ width.

An experimental study of the femtosecond laser machining of Si materials was carried out. Direct laser machining of the materials for the feature size of a few micron scale has the advantage of low cost and simple process comparing to the semiconductor process, E-beam lithography, ECM and other machining process. Further, the femtosecond laser is the better tool to machine the micro parts due to its characteristics of minimizing the heat affected zone(HAZ). As a result of line cutting of Si, the optimal condition had the region of the effective energy of 2mJ/㎜-2.5mJ/㎜ with the power of 0.5㎽-1.5㎽. The polarization effects of the incident beam existed in the machining qualities, therefore the sample motion should be perpendicular to the projection of the electric vector. We also observed the periodic ripple patterns which come out in condition of the pulse overlap with the threshold energy. Finally, we could machined the groove with the linewidth of below 2 ㎛ for the application of MEMS device repairing, scribing and arbitrary patterning.