In the present investigation, the relation of pre-ageing temperature and pre-ageing time to mechanical properties was studied, and a model was established to predict the mechanical properties of AA6005 Al alloy. Compa...In the present investigation, the relation of pre-ageing temperature and pre-ageing time to mechanical properties was studied, and a model was established to predict the mechanical properties of AA6005 Al alloy. Compared with the experimental results, the deviation of the proposed model was limited to 8.1%, which showed reasonable accuracy of forecasting. It was found that the performance of AA6005 alloy was better at higher pre-ageing temperature with shorter pre-ageing time than that at T6 temper. The microstructure of the alloy was observed by transmission electron microscopy, and the results showed that high dislocation density and precipitate density existed at 160 ℃ and 200 ℃ pre-ageing, which were in good agreement with the model.展开更多
This letter studies and analyzes the working features of main circuit of tri-level boost Power Factor Correct(PFC) converter and the advantages of tri-level switch converter in aspects of bearing high-voltage of power...This letter studies and analyzes the working features of main circuit of tri-level boost Power Factor Correct(PFC) converter and the advantages of tri-level switch converter in aspects of bearing high-voltage of power components,overall system loss and magnetic component selection based upon the single-level boost PFC switch converter.Besides,relying on the application of mi-croprocessor in power converter technology and DSP(Digital Signal Processing) chip's strong cal-culating capacity,the letter presents the adoption of modified scheme of tri-level boost PFC converter under the control of predictive control algorithm.Moreover,the operating principle and control method are specified,the results of circuit test and analysis are provided and the advantages of pre-dictive control technology-based multi-level boost PFC converter is verified.展开更多
Mixed bacteria were enriched from heavy metals mine soil for cadmium(Cd(Ⅱ))-containing wastewater treatment. Batch adsorption experiment results showed that the optimal pH, temperature, initial Cd(Ⅱ) concentration, ...Mixed bacteria were enriched from heavy metals mine soil for cadmium(Cd(Ⅱ))-containing wastewater treatment. Batch adsorption experiment results showed that the optimal pH, temperature, initial Cd(Ⅱ) concentration, and biomass dosage were 6.0, 30 ℃, 20 mg/L, and 1 g/L, respectively. Living biomass exhibited better Cd(Ⅱ) removal efficiency(91.97%) than autoclaved biomass(79.54%) under optimal conditions. The isotherms and kinetics of living biomass conformed to the Langmuir isotherm model and pseudo-first-order kinetic model, respectively. FTIR results implied that amine groups, hydroxyl groups and phosphoric acid play an important role in the Cd(Ⅱ) adsorption process, while XRD results showed that crystalline Cd(OH)and CdO were obtained. After Cd(Ⅱ)-containing wastewater treatment exposure, the dominant bacteria genera included Comamonas(39.94%), unclassified_f__Enterobacteriaceae(34.96%), Ochrobactrum(14.07%), Alcaligenes(4.84%), Bordetella(2.07%), Serratia(1.04%), and Bacillus(1.01%). Function prediction showed that the abundance of metabolic genes changed significantly. This study proposes the potential application of mixed bacteria for Cd(Ⅱ)-containing wastewater treatment.展开更多
It is difficult to detect the anomalies whose matching relationship among some data attributes is very different from others’ in a dataset. Aiming at this problem, an approach based on wavelet analysis for detecting ...It is difficult to detect the anomalies whose matching relationship among some data attributes is very different from others’ in a dataset. Aiming at this problem, an approach based on wavelet analysis for detecting and amending anomalous samples was proposed. Taking full advantage of wavelet analysis’ properties of multi-resolution and local analysis, this approach is able to detect and amend anomalous samples effectively. To realize the rapid numeric computation of wavelet translation for a discrete sequence, a modified algorithm based on Newton-Cores formula was also proposed. The experimental result shows that the approach is feasible with good result and good practicality.展开更多
The time forecast system of coal spontaneous combustion was described based on the KJ-90 mine environmental monitoring system in Hulipo Mine, Luzhou, Sichuan Province. In the system, CO and O2 sensor are added, and sp...The time forecast system of coal spontaneous combustion was described based on the KJ-90 mine environmental monitoring system in Hulipo Mine, Luzhou, Sichuan Province. In the system, CO and O2 sensor are added, and special-purpose microcomputer and software are equipped. By means of the system, the fluctuation laws of fire forecast parameters were observed in the process of coal-cutting, blast, exogenous mine fire and working face air quantity variation. This paper puts forward data processing method based on the Raita method.展开更多
基金Projects(51575539, U1837207) supported by the National Natural Science Foundation of ChinaProject(2020RC2002)supported by the Science and Technology Innovation Program of Hunan Province,ChinaProject(2021JJ40774)supported by Natural Science Foundation of Hunan Province,China。
文摘In the present investigation, the relation of pre-ageing temperature and pre-ageing time to mechanical properties was studied, and a model was established to predict the mechanical properties of AA6005 Al alloy. Compared with the experimental results, the deviation of the proposed model was limited to 8.1%, which showed reasonable accuracy of forecasting. It was found that the performance of AA6005 alloy was better at higher pre-ageing temperature with shorter pre-ageing time than that at T6 temper. The microstructure of the alloy was observed by transmission electron microscopy, and the results showed that high dislocation density and precipitate density existed at 160 ℃ and 200 ℃ pre-ageing, which were in good agreement with the model.
文摘This letter studies and analyzes the working features of main circuit of tri-level boost Power Factor Correct(PFC) converter and the advantages of tri-level switch converter in aspects of bearing high-voltage of power components,overall system loss and magnetic component selection based upon the single-level boost PFC switch converter.Besides,relying on the application of mi-croprocessor in power converter technology and DSP(Digital Signal Processing) chip's strong cal-culating capacity,the letter presents the adoption of modified scheme of tri-level boost PFC converter under the control of predictive control algorithm.Moreover,the operating principle and control method are specified,the results of circuit test and analysis are provided and the advantages of pre-dictive control technology-based multi-level boost PFC converter is verified.
基金supported by the National Natural Science Foundation of China (No. 52170164)the Open Project of Key Laboratory of Environmental Biotechnology,CAS (No. kf2018001)the Scientific Research Foundation for Returned Scholars at the University of South China (No. 2018XQD25)
文摘Mixed bacteria were enriched from heavy metals mine soil for cadmium(Cd(Ⅱ))-containing wastewater treatment. Batch adsorption experiment results showed that the optimal pH, temperature, initial Cd(Ⅱ) concentration, and biomass dosage were 6.0, 30 ℃, 20 mg/L, and 1 g/L, respectively. Living biomass exhibited better Cd(Ⅱ) removal efficiency(91.97%) than autoclaved biomass(79.54%) under optimal conditions. The isotherms and kinetics of living biomass conformed to the Langmuir isotherm model and pseudo-first-order kinetic model, respectively. FTIR results implied that amine groups, hydroxyl groups and phosphoric acid play an important role in the Cd(Ⅱ) adsorption process, while XRD results showed that crystalline Cd(OH)and CdO were obtained. After Cd(Ⅱ)-containing wastewater treatment exposure, the dominant bacteria genera included Comamonas(39.94%), unclassified_f__Enterobacteriaceae(34.96%), Ochrobactrum(14.07%), Alcaligenes(4.84%), Bordetella(2.07%), Serratia(1.04%), and Bacillus(1.01%). Function prediction showed that the abundance of metabolic genes changed significantly. This study proposes the potential application of mixed bacteria for Cd(Ⅱ)-containing wastewater treatment.
基金Project(50374079) supported by the National Natural Science Foundation of China
文摘It is difficult to detect the anomalies whose matching relationship among some data attributes is very different from others’ in a dataset. Aiming at this problem, an approach based on wavelet analysis for detecting and amending anomalous samples was proposed. Taking full advantage of wavelet analysis’ properties of multi-resolution and local analysis, this approach is able to detect and amend anomalous samples effectively. To realize the rapid numeric computation of wavelet translation for a discrete sequence, a modified algorithm based on Newton-Cores formula was also proposed. The experimental result shows that the approach is feasible with good result and good practicality.
基金Supported by National Natural Science Foundation of China (50274061) and National High Technology Research and Development Program of China(2003AA131100-02-06)
文摘The time forecast system of coal spontaneous combustion was described based on the KJ-90 mine environmental monitoring system in Hulipo Mine, Luzhou, Sichuan Province. In the system, CO and O2 sensor are added, and special-purpose microcomputer and software are equipped. By means of the system, the fluctuation laws of fire forecast parameters were observed in the process of coal-cutting, blast, exogenous mine fire and working face air quantity variation. This paper puts forward data processing method based on the Raita method.
