This paper proposes a method for establishing a power transformer fault tree based on fault cases. The method includes obtaining multiple fault cases of power transformers, dismantling multiple fault cases according to preset dismantling rules, classifying the faults of power transformers according to multiple fault cases, and establishing the basic framework of the fault tree. According to the results of dismantling, we are able to determine the logical relationship between the fault cause and the fault phenomenon of the power transformer. Based on the basic framework of the fault tree and the determined logical relationship, we build a fault tree for power transformers based on fault cases. This method will effectively improve the role of fault cases in the establishment of power transformer fault trees, realize fault identification and diagnosis of power transformers with high efficiency and high practicability, improve the efficiency of transformer fault analysis and disposal, and save power outage time caused by transformer faults.
Specific Emitter Identification (SEI) is the approach to identify emitter individuals using received wireless signals. Despite the fact that deep learning has been successfully applied in SEI, the performance is still unsatisfying when the receiver changes. In this paper, we introduce a domain adaptation method, namely Deep Adversarial Neural Network (DANN), for cross-receiver SEI. Furthermore, separated batch normalization (SepBN) is proposed to improve the performance. Results of experiments using real data show that the proposed SepBN-DANN method performs desirably for cross-receiver SEI.
HfO2 coatings are undoubtedly one of the most successful materials for high power laser applications. The ion beam assistance during the film growth is one of the most useful methods to obtain dense film along with improved optical and structural properties. As a consequence of the ever increasing application field of modern optical technologies, new demands for the optimization of deposition processes for high quality optical coatings with increased power handling capability, lower stress and optical uniformity are required for HfO2 film. In this paper, HfO2 films have been evaporated with ion assistance, provided by three different ion or plasma sources (APS, lion, RF). The influence of working gas flow (Ar and O2), ion energy and ion beam density on the HfO2 film properties was experimentally investigated. The film properties such as index of refraction, optical absorption and residual stress have been examined by spectrophotometry, laser calorimetry, and substrate curvature measurements. Microstructure have been studied by xray diffraction. Furthermore, a set of HfO2 monolayer were tested for LIDT at 1064 nm and 355nm for 10 ns pulses. The results suggest that the residual stress of HfO2 film is correlated with momentum transfer parameter, while both the ion energy and working gas flow maybe critical for the LIDT (absorption). The correlation between the microstructure and HfO2 film properties is discussed.
Publisher’s Note: This paper, originally published on 8 July 2019, was replaced with a corrected/revised version on 13 August 2019. If you downloaded the original PDF but are unable to access the revision, please contact SPIE Digital Library Customer Service for assistance.
In the continuous polishing process, the deformation caused by the uneven temperature distribution inside the optical element seriously affects the processing accuracy. This article combines domestic and international studies on the heat deformation of optical elements, and the formula for calculating the heat deformation of optical elements is proposed. Based on the Ansys software, the heat deformation of the element is simulated and analyzed, and the accuracy of the formula is verified. The effects of different shapes, materials, thicknesses, temperature difference on the heat deformation of the optical element are analyzed. After the optical element is processed, the temperature surface measurement experiment is performed to obtain the change of the temperature and the surface figure of the optical element in the cooling process, which has guided significance for improving the continuous polishing temperature field.
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