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Nearly equiatomic NiTi alloy is hydrothermally treated in a urea solution at 150°C to form nanostructures at the surface, with the aim to improve the structural quality of sol-gel deposited TiO2 film. Nanosheets film of ammonium titanate is formed on NiTi alloy after 8 h hydrothermal treatment, and the sol-gel TiO2 film on it is smooth and crack-free. Anatase TiO2 films consisting of nanoparticles and granular deposits are formed on the NiTi samples hydrothermally treated for 16 h and 24 h. The subsequently deposited TiO2 films have short cracks, because the nanostructured films can not completely balance volume shrinkage of the gel film during the drying and heat treatment processes. Water contact angles of the duplex treated NiTi samples increase during ageing in air, but are all reduced to below 10 after 2 h UV irradiation treatment. Potentiodynamic polarization tests in 0.9% NaCl solution indicate that the duplex treated NiTi samples have much better corrosion resistance than the polished one.

This investigation provides a hybrid Trefftz finite element approach for analysing orthotropic potential problem. For verification purpose, two examples are numerically investigated.

Target image recognition is an important issue in the information processing of imaging fuse system. In the paper, the main frame is proposed which can solve the problem of target image recognition and many computer simulation experiments are carried out. A recognition algorithm based on ant colony optimization and neural network is proposed. It overcomes the shortcomings of traditional BP algorithm and converges fast. The results of experiments prove that the presented algorithm can shorten the training time effectively and increase the accuracy of recognition, so it is very useful in improving the effective destroying ability of the missile.

A new four-node hybrid-Trefftz element is developed for plane elasticity problems. From the Airy stress function, the fundamental analytical solutions of the governing equation are derived as Trefftz functions for the intra-element (Trefftz) displacement field. Together with an independent frame displacement field along the element boundary, the element formulation is then constructed following the modified variational functional. Several numerical examples indicate that the proposed element exhibits good performance.

Image segmentation is an important technique for image processing and computer vision. The principles of 1-D Otsu’s algorithm and thresholding through index of fuzziness are described. Since the infrared images of tank have low object-background contrasts and blurred boundaries in the complex background condition, an adaptive algorithm for image thresholding through index of fuzziness, which is combined with the spatial correlative information, is proposed. The new method makes full use of the spatial correlation of pixels, so that it can extract the detail of the image from the complex background effectively, and improve the accuracy of the segmentation. The results of experiments prove that the presented algorithm has better performance and better robustness against noise.