A self-assembly method, named the angle controlled inclined deposition method, is developed for fabricating well-ordered silica and polystyrene colloidal crystals. A high-quality colloidal crystal with a flat and uniform surface over a large area can be produced rapidly using a minute quantity of suspension and without any additional equipment. By controlling the inclined angle, we can fabricate colloidal crystals with diverse numbers of layers. A colloidal crystal double-heterostructure (composed of three different colloidal photonic crystals) can be rapidly fabricated with this method. Both experimental and simulation results show that the photonic band gap of the double-heterostructure is not a simple superposition of that of the compositional colloidal crystals along the stacking direction. 相似文献
A novel mechanical anti-aliasing filtering fibre-optic hydrophone with a cylindrical Helmholtz resonator is con- structed and tested. The experimental results show that the hydrophone has a function of low-pass filtering. The low frequency acoustic sensitivity is about -160 dB （1 rad/#Pa）, and the response curve has a resonance deter- mined by the Helmholtz resonator. Theoretical and experimental results both show that the resonant frequency moves towards high frequency with the increasing orifice diameters. The sensitivity attenuation of high frequency is larger than lOdB. This new fibre-optic hydrophone is a prototype device for a class of sensors used to eliminate the aliasing in future sonar systems. 相似文献
Due to the mechanical stability of the PP layer, the oriented PP/PE double-layer film with a row-nucleated crystalline structure can be annealed at a higher temperature than the PE monolayer film. In this work, the effects of annealing temperature within the melting range of PE on the crystalline structure and properties of PP/PE double-layer films were studied. When the annealing temperature is between 100 and 130 °C, below the melting point of PE, the crystallinity, the long period, lateral dimension and orientation of the lamellae in the PE layer increase with the annealing temperature due to the melting of thin lamellae and the self-nucleated effect of partially-melted melts during annealing. With the annealing temperature further increasing to 138 °C, near the melting ending point of PE, since the lamellae melt completely and the melt memory becomes weak during annealing, some spherulite structures are formed in the annealed sample, resulting in a decrease of orientation. In contrast, the annealing only causes the appearance of a low-temperature endothermic plateau in the PP layer. The improved size and orientation of lamellar structure in the PE layer increase the pore arrangement and porosity of the stretched PP/PE microporous membrane. This study successfully applies the self-nucleation effect of partially-melted polymer melt into the practical annealing process, which is helpful to guide the production of high-performance PP/PE/PP lithium batteries separator and the annealing process of other multilayer products.
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