With the large-scale application and high-speed operation of electronic equipment, the thermal diffusion problem presents an increasing requirement for effective heat dissipation materials. Herein, high thermal conductive graphite films were fabricated via the graphitization of polyimide (PI) films with different amounts of chemical catalytic reagent. The results showed that chemically imidized PI (CIPI) films exhibit a higher tensile strength, thermal stability, and imidization degree than that of purely thermally imidized PI (TIPI) films. The graphite films derived from CIPI films present a more complete crystal orientation and ordered arrangement. With only 0.72% chemical catalytic reagent, the graphitized CIPI film achieved a high thermal conductivity of 1767 W·m−1·K−1, which is much higher than that of graphited TIPI film (1331 W·m−1·K−1), with an increase of 32.8%. The high thermal conductivity is attributed to the large in-plane crystallite size and high crystal integrity. It is believed that the chemical imidization method prioritizes the preparation of high-quality PI films and helps graphite films achieve an excellent performance.
Large-scale unmanned aerial vehicle (UAV) formations are vulnerable to disintegration under electromagnetic interference and fire attacks. To address this issue, this work proposed a distributed formation method of UAVs based on the 3 × 3 magic square and the chain rules of visual reference. Enlightened by the biomimetic idea of the plane formation of starling flocks, this method adopts the technical means of airborne vision and a cooperative target. The topological structure of the formation’s visual reference network showed high static stability under the measurement of the network connectivity index. In addition, the dynamic self-healing ability of this network was analyzed. Finally, a simulation of a battlefield using matlab showed that, when the loss of UAVs reaches 85% for formations with different scales, the UAVs breaking formation account for 5.1–6% of the total in the corresponding scale, and those keeping formation account for 54.4–65.7% of the total undestroyed fleets. The formation method designed in this paper can maintain the maximum number of UAVs in formation on the battlefield.
The faults of actuators and sensors can lead to abnormal operations or even system faults in multi-agent systems (MASs). To address this issue, this paper proposes an adaptive fault-tolerant control (FTC) algorithm for leaderless/leader–follower MASs against actuator and sensor faults. First, extended states integrating the fault components are constructed and the MAS is transformed into a descriptor system form. Then, a sliding-mode observer is designed for the transformed MAS. Based on the estimated MAS states and faults, adaptive FTC algorithms are developed, which update the control gains with the distributed tracking error. Finally, numerical simulations demonstrate that the proposed method can guarantee MAS stability against actuator and sensor faults.
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