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Mechanical metamaterials with multi-level dynamic crushing effects (MM-MLs) are designed in this study through coordinate transformation and mirror arrays. The mechanical effects of the diameter and length ratio of the struts and connecting rods, the Euler angles, and the cell numbers on the mechanical properties are investigated separately. MM-ML can exhibit significant two-level platform stress, and the local cells in the first platform stress stage undergo rotational motion, while the second platform stress stage mainly involves collapse compression and bending. Although increasing the length of the connecting rods can increase the range of Poisson's ratio, it will reduce the level of platform stress and energy absorption. Increasing the Euler angle will reduce the strain interval of the first platform stress and can improve the energy absorption capacity. In addition, increasing the cell number while maintaining a constant relative density can effectively enhance energy absorption. MM-ML has significant parameter controllability, can achieve different platform stress regions, different ranges of Poisson's ratios, and energy absorption requirements according to the application scenario, and can demonstrate functional diversity compared to existing research. The design scheme can provide ideas for adaptive crushing protection requirements.

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This paper focuses on the three-body confrontation problem of a Target-Defender team against an Attacker possessing greater maneuverability. Based on the input-to-state stability approach, a cooperative robust line-of-sight guidance law is proposed for the Target-Defender team to ensure that the Attacker has a certain tolerance range on the unavailable guidance information. In addition, the optimal evasion strategy is developed for the Target to maximize the terminal distance between the Target and Attacker. A key feature of the proposed guidance law is that the interception of the Attacker can be guaranteed as long as the uncertainty generated by the Attacker's maneuver is bounded. Furthermore, by using the optimal control technique, the control input of the Target-Defender team is minimized. Simulation examples are given to illustrate the effectiveness of the proposed guidance law.

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This article investigates the distributed optimal output consensus problem of heterogeneous linear multiagent systems over weight-unbalanced directed networks. A novel distributed continuous-time state feedback controller is proposed to steer the outputs of all the agents to converge to the optimal solution of the global cost function. Under the standard condition that the unbalanced digraph is strongly connected and the local cost functions are strongly convex with global Lipschitz gradients, the exponential convergence of the closed-loop multiagent system is established. Then, the proposed state feedback control law is extended to an observer-based output feedback setting. Two examples are finally provided to illustrate the effectiveness of the proposed control schemes.

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In this paper, we study the distributed Nash equilibrium (NE) seeking problem for a class of aggregative games with players described by uncertain perturbed nonlinear dynamics. To seek the NE, each player needs to construct a distributed algorithm based on information of its cost function and the exchanging information obtained from its neighbors. By combining the internal model principle and the average consensus technique, we propose a distributed gradient-based algorithm for the players. This paper not only assures the NE seeking of aggregative games but also achieves the disturbance rejection of external disturbances.

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Aim: In previous studies, numerous dysregulated long non-coding RNAs (lncRNAs) were identified by RNA-sequencing (RNA-seq). However, the relationship between lncRNA and osteosarcoma remains unclear. In the present study, the function and mechanism of lncRNA BE503655 were investigated. Methods: Transwell, cell cycle and proliferation were used to evaluate the function of lncRNA BE503655. Real-time PCR and Western blotting were used to detect the expression of lncRNA BE503655 and ß-catenin. Results: LncRNA BE503655 is overexpressed in human osteosarcoma and osteosarcoma cell lines. Knockdown lncRNA BE503655 suppresses cell proliferation, invasion and migration. High expression of BE503655 was significantly related to Enneking stage, distant metastasis and histological grade. Moreover, we also provided evidences that lncRNA BE503655 played its functions dependent on regulation of Wnt/ß-catenin signaling in osteosarcoma. Conclusion: Taken together, we verified the role of lncRNA BE503655 and provided possible mechanism in osteosarcoma. Our study provided new insights into clinical treatment of osteosarcoma and further intervention target.

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Size-fractionated heavy metal concentrations were observed in airborne particulate matter (PM) samples collected from 2014 to 2015 (spanning all four seasons) from suburban (Xianlin) and industrial (Pukou) areas in Nanjing, a megacity of southeast China. Rapid prediction models of size-fractionated metals were established based on multiple linear regression (MLR), back propagation artificial neural network (BP-ANN) and support vector machine (SVM) by using meteorological factors and PM concentrations as input parameters. About 38% and 77% of PM2.5 concentrations in Xianlin and Pukou, respectively, were beyond the Chinese National Ambient Air Quality Standard limit of 75 µg/m3. Nearly all elements had higher concentrations in industrial areas, and in winter among the four seasons. Anthropogenic elements such as Pb, Zn, Cd and Cu showed larger percentages in the fine fraction (ø≤2.5 µm), whereas the crustal elements including Al, Ba, Fe, Ni, Sr and Ti showed larger percentages in the coarse fraction (ø > 2.5 µm). SVM showed a higher training correlation coefficient (R), and lower mean absolute error (MAE) as well as lower root mean square error (RMSE), than MLR and BP-ANN for most metals. All the three methods showed better prediction results for Ni, Al, V, Cd and As, whereas relatively poor for Cr and Fe. The daily airborne metal concentrations in 2015 were then predicted by the fully trained SVM models and the results showed the heaviest pollution of airborne heavy metals occurred in December and January, whereas the lightest pollution occurred in June and July.

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A novel three-dimensional law based on input-to-state stability (ISS) and nonlinear robust H∞ filtering is proposed for interception of maneuvering targets in the presence of input saturation. A dead zone operator model is introduced to design an ISS-based guidance law to guarantee robust tracking of a maneuvering target. Input saturation and system stability are considered simultaneously, and the globally input-to-state stability have been ensured in theory. Since in practice line-of-sight (LOS) rate is difficult for a pursuer to measure accurately, the nonlinear robust H∞ filtering method is utilized to estimate it. The stability analyses and performed simulation results show that the presented approach is effective.

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The paper studies the distributed optimization problem for a class of nonlinear multiagent systems in the presence of external disturbances. To solve the problem, we need to achieve the optimal multiagent consensus based on local cost function information and neighboring information and meanwhile to reject local disturbance signals modeled by an exogenous system. With convex analysis and the internal model approach, we propose a distributed optimization controller for heterogeneous and nonlinear agents in the form of continuous-time minimum-phase systems with unity relative degree. We prove that the proposed design can solve the exact optimization problem with rejecting disturbances.