This paper deals with the global asymptotic stabilization and finite-time stabilization issues for variable-order fractional systems with partial a priori bounded disturbances by designing an appropriate adaptive controller. Via the inductive method and Arzela-Ascoli theorem, the existence and uniqueness of the solution for the considered system is firstly verified under the proposed control strategy. By applying Lyapunov stability theory, non-smooth analysis and inequality technique, sufficient stabilization criteria are established under the framework of variable-order fractional Filippov differential inclusion. Finally, two numerical simulations are given to demonstrate the validity of the proposed method.
In this work, Au-modified F-TiO2 is developed as a simple and efficient photocatalyst for H2O2 production under ultraviolet light. The Au/F-TiO2 photocatalyst avoids the necessity of adding fluoride into the reaction medium for enhancing H2O2 synthesis, as in a pure TiO2 reaction system. The F− modification inhibits the H2O2 decomposition through the formation of the ≡Ti–F complex. Au is an active cocatalyst for photocatalytic H2O2 production. We compared the activity of TiO2 with F− modification and without F− modification in the presence of Au, and found that the H2O2 production rate over Au/F-TiO2 reaches four times that of Au/TiO2. In situ electron spin resonance studies have shown that H2O2 is produced by stepwise single-electron oxygen reduction on the Au/F-TiO2 photocatalyst. 相似文献
This paper proposes a new method for eliminating impulse noise. Based on the space characteristic of object and noise, three kinds of basic noise patterns are introduced to describe noise and detect noise candidates. Correspondingly, noise removal operators are presented to remove the impulse noise. Extensive experiment results have shown that the proposed method is better than some of the state-of-the-art methods. 相似文献
In this paper, we propose a radial stereo imaging system for three-dimensional reconstruction of an object. This system uses a novel optical device which consists of a camera and two reflected mirrors. It can reconstruct three-dimensional model of an object by capturing one image. Depending on the reflection of the mirrors, each world point in the scene has a pair of points which sit in the inner and outer of the captured image, respectively. We firstly analyze the imaging constraint of the proposed system, and then derive the geometrical relationship between world point and image point pair to calculate the three-dimensional coordinate values of an arbitrary point on the object, which means that the three-dimensional model of the object can be recovered. Experiments are carried out to prove our design, and the results show that our radial stereo imaging system is convenient and effective for the three-dimensional reconstruction of an object. This system can be used in variety of applications, such as virtual reality and commodity show. 相似文献
Abstract Pottery sherds from the archaeological site of Bancun (Henan, China) were analyzed by Raman microscopy and the pigments used in the coating of this ancient (c. 4000–5000 BC) pottery were determined. It was found that bauxite was used to make the white pigment. The black coating was identified as a magnetite and its particle size was in the nanometer range. This work also showed that the size of pigment had influence on the color of the coating. In principle, Raman spectra could be used not only to identify the mineral source of the pigment but also to estimate the particle size of the pigments. 相似文献
Using an effect-barrier height method, we study the properties of the localized electronic states in an N-layer-based superlattice with structural defects within the framework of effective-mass theory. The coupling effect between normal and lateral degrees of freedom of an electron on the localized electronic states in both symmetric and asymmetric triple layer superlattices with structural defects has been considered numerically. The results show that the localized states display different behaviors in both symmetric and asymmetric structures in spite of the minibands being not influenced by the structural symmetry. Moreover, the coupling effect causes the minibands, minigaps and localized electron levels to depend on the transverse wave number kxy. A brief physical analysis is given. 相似文献