923 research outputs found

    Centralizers of derived-from-Anosov systems on T3\mathbb{T}^3: rigidity versus triviality

    Full text link
    In this paper, we study the centralizer of a partially hyperbolic diffeomorphism on T3\mathbb{T}^3 which is homotopic to an Anosov automorphism, and we show that either its centralizer is virtually trivial or such diffeomorphism is smoothly conjugate to its linear part.Comment: 24 page

    A Multilayer Feed Forward Small-World Neural Network Controller and Its Application on Electrohydraulic Actuation System

    Get PDF
    Being difficult to attain the precise mathematical models, traditional control methods such as proportional integral (PI) and proportional integral differentiation (PID) cannot meet the demands for real time and robustness when applied in some nonlinear systems. The neural network controller is a good replacement to overcome these shortcomings. However, the performance of neural network controller is directly determined by neural network model. In this paper, a new neural network model is constructed with a structure topology between the regular and random connection modes based on complex network, which simulates the brain neural network as far as possible, to design a better neural network controller. Then, a new controller is designed under small-world neural network model and is investigated in both linear and nonlinear systems control. The simulation results show that the new controller basing on small-world network model can improve the control precision by 30% in the case of system with random disturbance. Besides the good performance of the new controller in tracking square wave signals, which is demonstrated by the experiment results of direct drive electro-hydraulic actuation position control system, it works well on anti-interference performance

    Combustion Behaviour of Fe2O3-coated Zirconium Particles in Air

    Get PDF
    AbstractZirconium metal powder is widely used in aerospace and military as a metal fuel because of its high combustion rate and heat. This powder is used to produce flash powder, fireworks, artillery shells, timing bomb fuses and solid propellant rocket fuel. To comply with the special requirements for aerospace and military applications, zirconium particles are coated with Fe2O3 ferrite magnetite nanoparticles to form a core-shell structure. This process alters the combustion performance of the coated zirconium dust. In this study, the combustion behaviour of Fe2O3-coated zirconium particles in the air is explored. Scanning electron microscopy, X-ray diffraction, thermogravimetry and differential scanning calorimetry are used to examine the micromorphology, phase composition, crystal structure, thermal stability and reactivity of Fe2O3-coated zirconium particles. The combustion behaviour is presented, with the coating layer of Fe2O3-coated zirconium particles generating a replacement reaction with the inner core zirconium. The inner zirconium induced an oxidation-reduction reaction with oxygen and pure Fe was oxidised at high temperatures. The decomposition reaction was due to the residue of Fe2O3 that did not react with zirconium

    A multi-channel photometric detector for multi-component analysis in flow injection analysis

    Get PDF
    The detector, a multi-channel photometric detector, described in this paper was developed using multi-wavelength LEDs (light emitting diode) and phototransistors for absorbance measurement controlled by an Intel 8031 8-bit single chip microcomputer. Up to four flow cells can be attached to the detector. The LEDs and phototransistors are both inexpensive, and reliable. The results given by the detector for simultaneous determination of trace amounts of cobalt and cadmium in zinc sulphate electrolyte are reported. Because of the newly developed detector, this approach employs much less hardware apparatus than by employing conventional photometric detectors
    • …
    corecore