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We propose a new architecture, double-pass multiple-plate continuum (DPMPC), for nonlinear pulse compression. In addition to having a smaller footprint, a double-pass configuration is designed to achieve substantial bandwidth broadening without incurring noticeable higher-order dispersion, thus improving the temporal contrast over those of the traditional single-pass geometry when only the quadratic spectral phase can be compensated. In our proof-of-concept experiment, 187 μJ, 190-fs Yb-based laser pulse is compressed to 20 fs with high throughput (75%), high Strehl ratio (0.76), and excellent beam homogeneity by using DPMPC. The subsequently generated octave-spanning spectrum exhibits a significantly raised blue tail compared with that driven by pulses from a single-pass counterpart.

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A three-degrees-of-freedom model, including surge, sway and yaw motion, with differential thrusters is proposed to describe unmanned surface vehicle (USV) dynamics in this study. The experiment is carried out in the Qing Huai River and the data obtained from different zigzag trajectories are filtered by a Gaussian filtering method. A physics-informed neural network (PINN) is proposed to identify the dynamic models of the USV. PINNs combine the advantages of data-driven machine learning and physical models. They can also embed the speed and steering models into the loss function, which can significantly retain all types of information. Compared with traditional neural networks, the results show that the PINN has better generalization ability in predicting the surge and sway velocities and rotation speed with only limited training data.

We apply a Monte Carlo simulation method to lattice systems to study the effect of an intrinsic curvature on the mechanical property of a semiflexible biopolymer. We find that when the intrinsic curvature is sufficiently large, the extension of a semiflexible biopolymer can undergo a first-order transition at finite temperature. The critical force increases with increasing intrinsic curvature. However, the relationship between the critical force and the bending rigidity is structure-dependent. In a triangle lattice system, when the intrinsic curvature is smaller than a critical value, the critical force increases with the increasing bending rigidity first, and then decreases with the increasing bending rigidity. In a square lattice system, however, the critical force always decreases with the increasing bending rigidity. In contrast, when the intrinsic curvature is greater than the critical value, the larger bending rigidity always results in a larger critical force in both lattice systems.