Accurate displacement prediction is critical for the early warning of landslides.The complexity of the coupling relationship between multiple influencing factors and displacement makes the accurate prediction of displ...Accurate displacement prediction is critical for the early warning of landslides.The complexity of the coupling relationship between multiple influencing factors and displacement makes the accurate prediction of displacement difficult.Moreover,in engineering practice,insufficient monitoring data limit the performance of prediction models.To alleviate this problem,a displacement prediction method based on multisource domain transfer learning,which helps accurately predict data in the target domain through the knowledge of one or more source domains,is proposed.First,an optimized variational mode decomposition model based on the minimum sample entropy is used to decompose the cumulative displacement into the trend,periodic,and stochastic components.The trend component is predicted by an autoregressive model,and the periodic component is predicted by the long short-term memory.For the stochastic component,because it is affected by uncertainties,it is predicted by a combination of a Wasserstein generative adversarial network and multisource domain transfer learning for improved prediction accuracy.Considering a real mine slope as a case study,the proposed prediction method was validated.Therefore,this study provides new insights that can be applied to scenarios lacking sample data.展开更多
This study developed a direct reduction route to smelt refractory high-phosphorus iron ores by using hydrogen rich gas.The effects of temperature,gas composition,and gangue on the reduction behavior of iron ore pellet...This study developed a direct reduction route to smelt refractory high-phosphorus iron ores by using hydrogen rich gas.The effects of temperature,gas composition,and gangue on the reduction behavior of iron ore pellets were investigated.Additionally,the migration behavior of phosphorus throughout the reduction-smelting process was examined.The apparent activation energy of the reduction process increased from 64.2 to 194.2 kJ/mol.Increasing the basicity from 0.5 to 0.9 increased the metallization rate from 85.9%to 89.2%.During the reduction process,phosphorus remained in the gangue phase.Carbon deposition and phosphorus removal behaviors of the pellets were investigated and correlated with the gas composition,temperature,pressure,metallization rate,and basicity.Increasing the FeO and CaO contents led to an increase in the liquidus temperature.A high metallization rate of the pellets reduced the phosphorus removal rate but increased the carbon content of the final iron product.Increasing basicity restricted the migration of phosphorus and improved the rate of phosphorus removal.The optimum dephosphorization parameters were separation temperature of 1823 K,basicity of 2.0,and metallization rate of 82.3%.This study presents a high-efficiency and low carbon method for smelting high-phosphorus iron ores.展开更多
Multivariate analysis was adopted to analyze 30 morphometrical characteristics of 121 one-year-old juvenile silver carp (Hypophthalmichthys molitrix) and bighead carp (Aristichthys nobilis) bred during the 1950s ...Multivariate analysis was adopted to analyze 30 morphometrical characteristics of 121 one-year-old juvenile silver carp (Hypophthalmichthys molitrix) and bighead carp (Aristichthys nobilis) bred during the 1950s ("the former population") and 2008 ("the current population") and collected from the middle reach of the Yangtze River. The average discriminant accuracies of the former and current silver and bighead carp population were 94.2% and 98.0%, respectively. Discriminant analysis also revealed that significant differences in morphology occurred between the former and current populations of both carp in overall characteristics. One-way analysis of variance indicated that between former and current populations, silver carp showed highly significant differences (P0.01) in twelve of their characteristics and significant differences (P0.05) in eight of their characteristics, while bighead carp showed highly significant differences (P0.01) in eight of their characteristics and significant differences (P0.05) in eight of their characteristics. Six head morphology variables of the current silver and bighead carp were significantly or highly significantly larger than the former populations; fourteen characteristics of silver carp and ten characteristics of bighead carp of the current populations, mainly reflecting truck and tail morphology, were significantly or very significantly smaller than the former populations. Our results indicate that silver and bighead carp have developed a larger head and smaller truck and tail during the last 50 years. Due to such morphological changes, it seems apparent that the heads of these fish species need to be considered in regards to human diets, particularly in relation to economic and nutritious value.展开更多
The dynamic recrystallization behavior of 7085 aluminum alloy during hot compression at various temperatures (573?723 K) and strain rates (0.01-10 s^-1) was studied by electron back scattered diffraction (EBSD...The dynamic recrystallization behavior of 7085 aluminum alloy during hot compression at various temperatures (573?723 K) and strain rates (0.01-10 s^-1) was studied by electron back scattered diffraction (EBSD), electro-probe microanalyzer (EPMA) and transmission electron microscopy (TEM). It is shown that dynamic recovery is the dominant softening mechanism at high Zener?Hollomon (Z) values, and dynamic recrystallization tends to appear at low Z values. Hot compression with ln Z=24.01 (723 K, 0.01 s?1) gives rise to the highest fraction of recrystallization of 10.2%. EBSD results show that the recrystallized grains are present near the original grain boundaries and exhibit similar orientation to the deformed grain. Strain-induced boundary migration is likely the mechanism for dynamic recrystallization. The low density of Al3Zr dispersoids near grain boundaries can make contribution to strain-induced boundary migration.展开更多
The variation and influence factors of yield gravity center of flue-cured tobacco in Hunan were studied in 2006-2015 by regional gravity center method and grey correlation analysis. The results showed that the yields ...The variation and influence factors of yield gravity center of flue-cured tobacco in Hunan were studied in 2006-2015 by regional gravity center method and grey correlation analysis. The results showed that the yields of flue-cured tobacco in various areas in Hunan were mainly of the growing with fluctuation type. The yield gravity centers in the whole province and eastern, southern and western Hunan tobacco-growing areas overall moved in the north by west, south by west, west by south, and south by east directions, respectively; and the movements in the south-north direction were in order of eastern Hunan tobacco-growing area 〉whole province 〉western Hunan tobacco-growing area 〉southern Hunan tobacco-growing area, and the movements inthe east-west direction showed an order of eastern Hunan tobecco-growing area〉western Hunan tobacco-growing area〉whole province〉 southern Hunan tobacco-growing area. The main influence factors of the coordinates of the longitudes and the latitudes differed. The main influence factor was planting area in most cities or counties in the whole province, and was per unit area yield in a few cities or counties. It is advised to construct the "one main body and two wings" development pattern of flue-cured tobacco production in Hunan with southern Hunan tobacco-growing area as the main body and western and eastern Hunan tobacco-growing areas as the two wings.展开更多
The fabrication and characterization of strained-Si material grown on a relaxed Si0.79 Ge0.21/graded Si1-x- Gex/Si virtual substrate, using reduced pressure chemical vapor deposition, are presented. The Ge concentrati...The fabrication and characterization of strained-Si material grown on a relaxed Si0.79 Ge0.21/graded Si1-x- Gex/Si virtual substrate, using reduced pressure chemical vapor deposition, are presented. The Ge concentration of the constant composition SiGe layer and the grading rate of the graded SiGe layer are estimated with double-crystal X-ray diffraction and further confirmed by SIMS measurements. The surface root mean square roughness of the strained Si cap layer is 2.36nm,and the strain is about 0.83% as determined by atomic force microscopy and Raman spectra, respectively. The threading dislocation density is on the order of 4 × 10^4cm^-2. Furthermore, it is found that the stress in the strained Si cap layer is maintained even after the high thermal budget process, nMOSFET devices are fabricated and measured in strained-Si and unstrained bulk-Si channels. Compared to the co-processed bulk-Si MOSFETs at room temperature,a significant low vertical field mobility enhancement of about 85% is observed in the strained-Si devices.展开更多
A novel approach based on the quantitative phase field model was proposed to calculate the interface mobility and applied to the α/β interface of a ternary Ti-6Al-4V alloy.Phase field simulations indicate that the h...A novel approach based on the quantitative phase field model was proposed to calculate the interface mobility and applied to the α/β interface of a ternary Ti-6Al-4V alloy.Phase field simulations indicate that the higher interface mobility leads to the faster transformation rate,but only a unique value of interface mobility matches the diffusion equation under the diffusion-controlled condition.By comparing the transformation kinetics from phase field simulations with that from classical diffusion equation,the interface mobility at different temperatures can be obtained.The results show that the calculated interface mobility increases with increasing temperature and accords with Arrhenius equation very well.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.51674169)Department of Education of Hebei Province of China(Grant No.ZD2019140)+1 种基金Natural Science Foundation of Hebei Province of China(Grant No.F2019210243)S&T Program of Hebei(Grant No.22375413D)School of Electrical and Electronics Engineering。
文摘Accurate displacement prediction is critical for the early warning of landslides.The complexity of the coupling relationship between multiple influencing factors and displacement makes the accurate prediction of displacement difficult.Moreover,in engineering practice,insufficient monitoring data limit the performance of prediction models.To alleviate this problem,a displacement prediction method based on multisource domain transfer learning,which helps accurately predict data in the target domain through the knowledge of one or more source domains,is proposed.First,an optimized variational mode decomposition model based on the minimum sample entropy is used to decompose the cumulative displacement into the trend,periodic,and stochastic components.The trend component is predicted by an autoregressive model,and the periodic component is predicted by the long short-term memory.For the stochastic component,because it is affected by uncertainties,it is predicted by a combination of a Wasserstein generative adversarial network and multisource domain transfer learning for improved prediction accuracy.Considering a real mine slope as a case study,the proposed prediction method was validated.Therefore,this study provides new insights that can be applied to scenarios lacking sample data.
基金Project(U1960205)supported by the National Natural Science Foundation of ChinaProject(2020ZXA01)supported by China Minmetals Science and Technology Special Plan Foundation。
文摘This study developed a direct reduction route to smelt refractory high-phosphorus iron ores by using hydrogen rich gas.The effects of temperature,gas composition,and gangue on the reduction behavior of iron ore pellets were investigated.Additionally,the migration behavior of phosphorus throughout the reduction-smelting process was examined.The apparent activation energy of the reduction process increased from 64.2 to 194.2 kJ/mol.Increasing the basicity from 0.5 to 0.9 increased the metallization rate from 85.9%to 89.2%.During the reduction process,phosphorus remained in the gangue phase.Carbon deposition and phosphorus removal behaviors of the pellets were investigated and correlated with the gas composition,temperature,pressure,metallization rate,and basicity.Increasing the FeO and CaO contents led to an increase in the liquidus temperature.A high metallization rate of the pellets reduced the phosphorus removal rate but increased the carbon content of the final iron product.Increasing basicity restricted the migration of phosphorus and improved the rate of phosphorus removal.The optimum dephosphorization parameters were separation temperature of 1823 K,basicity of 2.0,and metallization rate of 82.3%.This study presents a high-efficiency and low carbon method for smelting high-phosphorus iron ores.
基金National Natural Science Foundation of China (30630051)Aquaculture E-Institute of Shanghai Universities(03E009)Shanghai Leading Academic Discipline Project(S30701)
文摘Multivariate analysis was adopted to analyze 30 morphometrical characteristics of 121 one-year-old juvenile silver carp (Hypophthalmichthys molitrix) and bighead carp (Aristichthys nobilis) bred during the 1950s ("the former population") and 2008 ("the current population") and collected from the middle reach of the Yangtze River. The average discriminant accuracies of the former and current silver and bighead carp population were 94.2% and 98.0%, respectively. Discriminant analysis also revealed that significant differences in morphology occurred between the former and current populations of both carp in overall characteristics. One-way analysis of variance indicated that between former and current populations, silver carp showed highly significant differences (P0.01) in twelve of their characteristics and significant differences (P0.05) in eight of their characteristics, while bighead carp showed highly significant differences (P0.01) in eight of their characteristics and significant differences (P0.05) in eight of their characteristics. Six head morphology variables of the current silver and bighead carp were significantly or highly significantly larger than the former populations; fourteen characteristics of silver carp and ten characteristics of bighead carp of the current populations, mainly reflecting truck and tail morphology, were significantly or very significantly smaller than the former populations. Our results indicate that silver and bighead carp have developed a larger head and smaller truck and tail during the last 50 years. Due to such morphological changes, it seems apparent that the heads of these fish species need to be considered in regards to human diets, particularly in relation to economic and nutritious value.
基金Project(2012CB619500)supported by the National Basic Research Program of China
文摘The dynamic recrystallization behavior of 7085 aluminum alloy during hot compression at various temperatures (573?723 K) and strain rates (0.01-10 s^-1) was studied by electron back scattered diffraction (EBSD), electro-probe microanalyzer (EPMA) and transmission electron microscopy (TEM). It is shown that dynamic recovery is the dominant softening mechanism at high Zener?Hollomon (Z) values, and dynamic recrystallization tends to appear at low Z values. Hot compression with ln Z=24.01 (723 K, 0.01 s?1) gives rise to the highest fraction of recrystallization of 10.2%. EBSD results show that the recrystallized grains are present near the original grain boundaries and exhibit similar orientation to the deformed grain. Strain-induced boundary migration is likely the mechanism for dynamic recrystallization. The low density of Al3Zr dispersoids near grain boundaries can make contribution to strain-induced boundary migration.
文摘The variation and influence factors of yield gravity center of flue-cured tobacco in Hunan were studied in 2006-2015 by regional gravity center method and grey correlation analysis. The results showed that the yields of flue-cured tobacco in various areas in Hunan were mainly of the growing with fluctuation type. The yield gravity centers in the whole province and eastern, southern and western Hunan tobacco-growing areas overall moved in the north by west, south by west, west by south, and south by east directions, respectively; and the movements in the south-north direction were in order of eastern Hunan tobacco-growing area 〉whole province 〉western Hunan tobacco-growing area 〉southern Hunan tobacco-growing area, and the movements inthe east-west direction showed an order of eastern Hunan tobecco-growing area〉western Hunan tobacco-growing area〉whole province〉 southern Hunan tobacco-growing area. The main influence factors of the coordinates of the longitudes and the latitudes differed. The main influence factor was planting area in most cities or counties in the whole province, and was per unit area yield in a few cities or counties. It is advised to construct the "one main body and two wings" development pattern of flue-cured tobacco production in Hunan with southern Hunan tobacco-growing area as the main body and western and eastern Hunan tobacco-growing areas as the two wings.
文摘The fabrication and characterization of strained-Si material grown on a relaxed Si0.79 Ge0.21/graded Si1-x- Gex/Si virtual substrate, using reduced pressure chemical vapor deposition, are presented. The Ge concentration of the constant composition SiGe layer and the grading rate of the graded SiGe layer are estimated with double-crystal X-ray diffraction and further confirmed by SIMS measurements. The surface root mean square roughness of the strained Si cap layer is 2.36nm,and the strain is about 0.83% as determined by atomic force microscopy and Raman spectra, respectively. The threading dislocation density is on the order of 4 × 10^4cm^-2. Furthermore, it is found that the stress in the strained Si cap layer is maintained even after the high thermal budget process, nMOSFET devices are fabricated and measured in strained-Si and unstrained bulk-Si channels. Compared to the co-processed bulk-Si MOSFETs at room temperature,a significant low vertical field mobility enhancement of about 85% is observed in the strained-Si devices.
基金Project (51101059) supported by the National Natural Science Foundation of ChinaProject (20110490874) supported by the China Postdoctoral Science Foundation
文摘A novel approach based on the quantitative phase field model was proposed to calculate the interface mobility and applied to the α/β interface of a ternary Ti-6Al-4V alloy.Phase field simulations indicate that the higher interface mobility leads to the faster transformation rate,but only a unique value of interface mobility matches the diffusion equation under the diffusion-controlled condition.By comparing the transformation kinetics from phase field simulations with that from classical diffusion equation,the interface mobility at different temperatures can be obtained.The results show that the calculated interface mobility increases with increasing temperature and accords with Arrhenius equation very well.