A method based on multiscale base-scale entropy and random forests for roller bearings faults diagnosis

A method based on multiscale base-scale entropy (MBSE) and random forests (RF) for roller bearings faults diagnosis is presented in this study. Firstly, the roller bearings vibration signals were decomposed into base-scale entropy (BSE), sample entropy (SE) and permutation entropy (PE) values by using MBSE, multiscale sample entropy (MSE) and multiscale permutation entropy (MPE) under different scales. Then the computation time of the MBSE/MSE/MPE methods were compared. Secondly, the entropy values of BSE, SE, and PE under different scales were regarded as the input of RF and SVM optimized by particle swarm ion (PSO) and genetic algorithm (GA) algorithms for fulfilling the fault identification, and the classification accuracy was utilized to verify the effect of the MBSE/MSE/MPE methods by using RF/PSO/GA-SVM models. Finally, the experiment result shows that the computational efficiency and classification accuracy of MBSE method are superior to MSE and MPE with RF and SVM

A highly efficient coordination polymer for selective trapping and sensing of perrhenate/pertechnetate

This work was financially supported by the National Natural Science Foundation of China (21771139), Tianjin Natural Science Foundation (17JCYBJC22800), and the Program for Innovative Research Team in University of Tianjin (TD13-5074).A porous cationic Ag(I) coordination polymer, [Ag(1,2,4,5-p4b)](SbF6) (TJNU-302) with the ligand 1,2,4,5-p4b (1,2,4,5-tetra(pyridin-4-yl)benzene), is reported that shows high sorption capacity (211 mg g–1) and distribution coefficient Kd (5.8 × 105 mL g–1) as well as outstanding selectivity in 500 times excess of CO32– or PO43– anion for perrhenate removal. TJNU-302 can act as a crystalline turn-off sensor for perrhenate upon UV radiation. In this way, a test paper strip for sensing ReO4– could be produced. In water solution, TJNU-302 shows an efficient fluorescence quenching response to ReO4– ion, with the highest quenching percentage (86%) among all reported ReO4– sensors. These results could be elucidated by the bonding properties of single-crystal structures of TJNU-302 before and after perrhenate sorption, as well as density functional theory (DFT) calculations.PostprintPeer reviewe