1,382 research outputs found
Manipulating thermal conductivity through substrate coupling
We report a new approach to the thermal conductivity manipulation --
substrate coupling. Generally, the phonon scattering with substrates can
decrease the thermal conductivity, as observed in recent experiments. However,
we find that at certain regions, the coupling to substrates can increase the
thermal conductivity due to a reduction of anharmonic phonon scattering induced
by shift of the phonon band to the low wave vector. In this way, the thermal
conductivity can be efficiently manipulated via coupling to different
substrates, without changing or destroying the material structures. This idea
is demonstrated by calculating the thermal conductivity of modified
double-walled carbon nanotubes and also by the ice nanotubes coupled within
carbon nanotubes.Comment: 5 figure
Asymptotical Cooperative Cruise Fault Tolerant Control for Multiple High-speed Trains with State Constraints
This paper investigates the asymptotical cooperative cruise fault tolerant
control problem for multiple high-speed trains consisting of multiple carriages
in the presence of actuator faults. A distributed state-fault observer
utilizing the structural information of faults is designed to achieve
asymptotical estimation of states and faults of each carriage. The observer
does not rely on choice of control input, and thus it is separated from
controller design. Based on the estimated values of states and faults, a
distributed fault tolerance controller is designed to realize asymptotical
cooperative cruise control of trains under the dual constraints of ensuring
both position difference and velocity difference of adjacent trains in
specified ranges throughout the whole process.Comment: 12 pages, 9 figure
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