The distributed output-feedback tracking control for a class of networked multiagents in nonaffine pure-feedback form is investigated in this article. By introducing a low-pass filter and some auxiliary variables, we first transform the nonaffine system into the affine form. Then, the finite-time observer is designed to estimate the states of the newly derived affine system. By applying the fraction dynamic surface control approach and the neural network-based approximation technique, the distributed output-feedback control laws are proposed and it is proved that the tracking errors converge to an arbitrarily small bound around zero in finite time. Finally, some simulation examples are provided to confirm the effectiveness of the developed method. K E Y W O R D Sfinite-time, multiagent systems, nonaffine system, output-feedback, pure-feedback system

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In this report the temperature-dependent photoluminescence spectra, Fourier transform infrared (FTIR) spectra and time-resolved FTIR spectra of freshly prepared porous silicon and oxidized porous silicon are examined. The experimental results indicate that there is a gradual transformation of electronic states with ageing in air, because ageing led to the surface oxidation and size reduction of Si nanostructures. This surface variation from hydrogen to oxygen during ageing leads to a red shift of the emissions. A clear quantum-confinement effect exists for both H-and O-capped porous silicon but the emissions in O-capped porous silicon show clear polaronic nature. The photoinduced polaron is evidenced by the time-resolved FTIR results. A reversible H-detrapping process in silicon wafer occurs with temperature, which influences the conduction of silicon wafer and the photoluminescence of as-prepared porous silicon due to the carrier density changes.

The ditching processes of a blended-wing–body (BWB) aircraft under different initial speeds and pitch angles are simulated by numerically solving the unsteady Reynolds-averaged Navier–Stokes equations and the realizable [Formula: see text] turbulence model using the finite volume method. The volume-of-fluid model is adopted to capture the water–air interface. The six-degree-of-freedom model is employed to couple fluid dynamics and aircraft rigid-body kinematics. The global moving mesh is used to deal with the relative motion between the aircraft and the water. It is found that the plane composed of initial speed and pitch angle can be divided into two regions by a stability limit line, that is, the porpoising motion region (the aircraft takes coupled oscillatory motion between heaving and pitching) with large initial speeds and pitch angles and the stable motion region with low initial speeds and pitch angles. When the initial speed is large, the aircraft’s pitch-up moment peak and heaving amplitude are enhanced. Hence the aircraft carries out the porpoising motion. For the large initial pitch angle, the water entry depth of the aircraft increases and the waterline moves forward, which produces a more significant pitch-up moment peak and overload peak. As a result, the aircraft conducts the porpoising motion. The porpoising stability of the BWB configuration is obviously worse than the conventional and flying wing configurations. When the BWB aircraft ditches on water, the pilots should reduce the initial speed and pitch angle as much as possible to avoid the dangerous porpoising motion.

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