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Smooth model of blasting seismic wave signal denoising based on two-stage denoising algorithm
Sun Miao,Wu Li,Li Chunjun,Yuan Qing,Zhou Yuchun,Ouyang Xu 한국자원공학회 2020 Geosystem engineering Vol.23 No.4
In this paper, a two-stage denoising algorithm is proposed. Complementary ensemble empirical mode decomposition based on permutation entropy (CEEMD-PE) is carried out for the noisy monitoring signal in the first stage. Several denoising models are established according to the intrinsic mode function obtained by CEEMD-PE. An objective function considers both the smoothness of the denoising model and the similarity between the denoising model and the noisy monitoring signal is established, and the second stage denoising is realized by solving the objective function. The denoising model corresponding to the optimal solution of the objective function is the smooth denoising model. In order to verify the correctness of the two-stage denoising algorithm, the mixed simulation signal with noise is denoised, and based on the definition of signal-to-noise ratio, the effect of two-stage denoising is calculated. Finally, the algorithm is applied to the actual blasting seismic signal denoising processing. It is found that the proposed algorithm can not only reduce the noise interference but also retain the real part of the original signal while filtering the noise.
Liu Ning,You Fangtian,Ji Chao,Gong Hongkang,Song Qi,Li Jiasen,Liang Chunjun,He Zhiqun 한국물리학회 2021 Current Applied Physics Vol.31 No.-
Perovskite light-emitting diodes (PeLEDs) prepared by the all-solution-process are gradually coming into view due to their low cost and flexible production process. However, the performance of CsPbBr3 device is limited by the high non-radiative recombination losses due to incomplete surface coverage and grain defects. Here a quaternary ammonium salt, tetrabutylammonium hexafluorophosphate (TBA-PF6) was simultaneously introduced into perovskite emission layers (CsPbBr3) and electron transport layer (TPBi (1,3,5-Tris(1-phenyl-1Hbenzimidazol- 2-yl) benzene) dissolved in ethyl acetate). As a result, the morphology and luminescence of CsPbBr3 films were improved, and the energy level of TPBi was more conducive to charge transport. Consequently, the maximum luminance and current efficiency of the modified green-emitting PeLEDs are improved. Furthermore, the optimized device had an operating life of more than 20 min at an initial luminance of 1230 cd/ m2. This work provides a simple and easy method to be scaled up for the development of low-cost all-solutionprocessed PeLEDs.