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The formation and evolution of laser-induced periodic structures (LIPSS) have attracted much attention due to their broad applications and rich physics. The literature has shown that excessive laser energy accumulation, such as increasing single pulse energy or cumulative pulse number on a sample, leads to a final fuzzy LIPSS period or even disappearance of the period. This article discovers a new phenomenon by increasing the laser fluence; the periodic structure appears blurred and disappears in the middle of the laser fluence region. Two contrary evolution tendencies of the period’s disappearance are observed for the first time. This phenomenon can be attributed to femtosecond ablation regimes in different fluence regions. The experimental results and discussion provide a powerful guarantee for the high-quality preparation of structures by controlling the experimental parameters for future practical applications. The findings of this study play a significant role in regulating the LIPSS period and provide ideas for avoiding the hidden danger of the cycle structure disappearing during the creation of the LIPSS structure, which has practical implications for future LIPSS applications.

The spatiotemporal mobility patterns and next location prediction of fake base stations (FBS) provide important technical support for the police to prevent spam messages from FBS. However, due to the difficulty in locating their real-time locations, our understanding of the mobility patterns and predictability of FBS is still limited. Based on the crowdsourced spam data, we extract the time and potential locations of FBS and propose a Tucker-MMC method that combines Tucker decomposition with a Mobility Markov Chain (MMC) model to investigate the mobility patterns and predictability of FBS sending spam messages. First, we utilize Tucker decomposition to reflect the spatial and temporal preferences during the movement of the corresponding FBS. Then the mobility regularity and the theoretical maximum predictability of the FBS trajectories with similar mobility preferences are analyzed by entropy and Fano's inequality. A Tucker-MMC is also established for the next location prediction. The results using the spam dataset in Beijing show that the accuracy of Tucker-MMC is more than double that of the MMC. The accuracy of the actual location prediction model is more likely to approach the theoretical maximum predictability when FBS send spam messages in a shorter time, shorter transfer distance, and smaller access range. [ABSTRACT FROM AUTHOR]

In order to better analyze and design the fabric structure, a layering overlay method is proposed for the fabrics with the layering relationship of backed weave, sandwich and double layers. According to the spatial relationship between the upper and lower layers of the fabric, the warp and weft yarns of different fabric layers are represented by the dark and light color groups of different shade, and the layers are drawn successively from the lower layer, the interlayer to the upper layer. The drawing method of layering overlay method is introduced with fabric CAD and Photoshop (PS) as application conditions, and the application of this method in fabric structure analysis and design is illustrated. When fabric CAD is used, the inner yarn and its interweaving law, the connecting yarn, the surface yarn and its interweaving law are superimposed from bottom to top. When drawing with PS, each layer of yarn and its interweaving rule are drawn on different layers respectively, and the upper and lower positions of the layers are adjusted according to the relationship between the layers in the fabric surface. Layering and superposition method makes the process of fabric drawing more intuitive, clear and convenient. It is helpful for designers to analyze, understand and innovate fabrics. [ABSTRACT FROM AUTHOR]