In order to improve the operation reliability of the three⁃level PV inverter, an open⁃circuit fault detection and a voltage space vector redundancy fault⁃tolerant control method based on the improved current flow path were proposed. First, based on the three⁃phase three⁃level PV topology structure, the circuit current flow path after the open⁃circuit fault of each partial power device was analyzed in detail, the fault detection could be carried out by the current size flowing through the clamping diode and the load, the switching state of the switching device, and the fault type could be classified by injecting the under⁃excitation reactive current in a short time. Then, the change of the voltage space vector of the inverter after the open⁃circuit fault of the power device in different positions was theoretically explored. And the fault⁃tolerant control was completed according to the distribution law of the voltage space vector after the inverter fault and the redundancy vector of the inverter. The proposed method was fast in fault detection and fault⁃tolerant control without additional hardware cost and complex calculation. Finally, a prototype with rated power of 10 kW was built to verify the effectiveness and reliability of the proposed method.

Reconstruction of rippedup documents was important for judicial authentication，cultural relic reconstruction and military information acquisition，etc．An approach for the reconstruction of regularly rippedup documents was proposed. Firstly, the line spacing of the fragments was automatically extracted. Secondly, meanshift algorithm was adapted to cluster all the fragments. Thirdly, for each cluster, the similarity matrix was constructed based on the grayscale of the edges of the fragments. Lastly, the document with genetic algorithm was reconstructed.Reconstruction of rippedup documents is important for judicial authentication，cultural relic reconstruction and military information acquisition，etc．In this paper，we propose an approach for the reconstruction of regularly rippedup documents. Firstly, the line spacing of the fragments is automatically extracted|Then meanshift algorithm is adapted to cluster all the fragments|Then for each cluster, the similarity matrix is constructed based on the grayscale of the edges of the fragments|Lastly, we reconstruct the document with genetic algorithm.

Perovskitetype oxide Ba0.6Sr0.4Co0.9Nb0.1O3δ (BSCN) was synthesized by the solid state reaction and investigated as a cathode for intermediatetemperature solidoxide fuel cells (ITSOFCs). XRD pattern indicated that BSCN crystallized in a singlephase perovskite with a cubic perovskite structure (Pm3m) and no evident reaction happened after the mixture of BSCN cathode and GDC electrolyte was sintered at 1 000 ℃ for 10 h. During the operating temperature of SOFCs (600~800 ℃), the electrical conductivity of BSCN reaches 21~27 S/cm. The thermal expansion coefficient value of 17.0 × 10-6/K has been measured for BSCN sample, which is much lower than that of SrCo0.9Nb0.1O3δ(SCN). This result indicated that Ba doping in SCN has a better thermal match to GDC electrolyte. Symmetrical cell with the configuration of BSCN/GDC/BSCN was used for the impedance measurements. The polarization resistance of BSCN cathode on GDC electrolyte is 0.026 Ω·cm2 at 750 ℃. With BSCN cathode, NiOCe0.8Sm0.2O1.9 anode and 300 μm thick GDC electrolyte, the maximum power density of single cell achieved 782 mW/cm2 at 800 ℃. All these results indicate that the BSCN oxide is a promising cathode candidate material for ITSOFCs.