In order to utilize the wasted saline-sodic soils under shallow groundwater condition, a 3-year field study was carried in a field cropped with Lycium barbarum L. and irrigated by drip irrigation with saline groundwat...In order to utilize the wasted saline-sodic soils under shallow groundwater condition, a 3-year field study was carried in a field cropped with Lycium barbarum L. and irrigated by drip irrigation with saline groundwater under the water table depth of 30-40 cm in the northern Yinchuan Plain, China. Effects of cropping duration （one, two, and three years） on soil salinity, soil solution composition, and pH in three adjacent plots were investigated in 2008. Results showed that a high irrigation frequency maintained high soil water potential and subsequently facilitated infiltration and downward movement of water and salt in the crop root zone. Salt accumulated on the edges of the ridges, and soil saturated-paste electrical conductivity （ECe） was higher in the edge. Concentrations of Na^＋, Ca^2＋, Mg^2＋, Cl^-, and SO24^- in the soil increased with the soil depth as did the ECe, while HCO3 and pH had a relative uniform distribution in soil profile. As planting year increased, the ECe and soil salts in the field had a decreasing tendency, while in the root zone they decreased immediately after irrigation and then remained relatively stable in the following growing seasons. HCO3 and pH had little change with the planting year. Results suggested that the application of drip irrigation with saline water could ameliorate saline-sodic soil and provide a relatively feasible soil environment for saline-sodic soils with shallow groundwater.展开更多
Abstract Advanced crack monitoring technique is the cornerstone of aircraft structural health monitoring. To achieve realtime crack monitoring of aircraft metal structures in the course of ser vice, a new crack monito...Abstract Advanced crack monitoring technique is the cornerstone of aircraft structural health monitoring. To achieve realtime crack monitoring of aircraft metal structures in the course of ser vice, a new crack monitoring method is proposed based on Cu coating sensor and electrical poten tial difference principle. Firstly, insulation treatment process was used to prepare a dielectric layer on structural substrate, such as an anodizing layer on 2AI2T4 aluminum alloy substrate, and then a Cu coating crack monitoring sensor was deposited on the structure fatigue critical parts by pulsed bias arc ion plating technology. Secondly, the damage consistency of the Cu coating sensor and 2A12T4 aluminum alloy substrate was investigated by static tensile experiment and fatigue test. The results show that strain values of the coating sensor and the 2A 12T4 aluminum alloy substrate measured by strain gauges are highly coincident in static tensile experiment and the sensor has excel lent fatigue damage consistency with the substrate. Thirdly, the fatigue performance discrepancy between samples with the coating sensor and original samples was investigated. The result shows that there is no obvious negative influence on the fatigue performance of the 2A12T4 aluminum alloy after preparing the Cu coating sensor on its surface. Finally, crack monitoring experiment was carried out with the Cu coating sensor. The experimental results indicate that the sensor is sensitive to crack, and crack origination and propagation can be monitored effectively through analyzing the change of electrical potential values of the coating sensor.展开更多
Borehole-to-surface electrical imaging （BSEI） uses a line source and a point source to generate a stable electric field in the ground. In order to study the surface potential of anomalies, three-dimensional forward ...Borehole-to-surface electrical imaging （BSEI） uses a line source and a point source to generate a stable electric field in the ground. In order to study the surface potential of anomalies, three-dimensional forward modeling of point and line sources was conducted by using the finite-difference method and the incomplete Cholesky conjugate gradient （ICCG） method. Then, the damping least square method was used in the 3D inversion of the formation resistivity data. Several geological models were considered in the forward modeling and inversion. The forward modeling results suggest that the potentials generated by the two sources have different surface signatures. The inversion data suggest that the low- resistivity anomaly is outlined better than the high-resistivity anomaly. Moreover, when the point source is under the anomaly, the resistivity anomaly boundaries are better outlined than when using a line source.展开更多
Low-voltage electrical apparatuses(LVEAs)have many workpieces and intricate geometric structures,and the assembly process is rigid and labor-intensive,and has little balance.The assembly process cannot readily adapt t...Low-voltage electrical apparatuses(LVEAs)have many workpieces and intricate geometric structures,and the assembly process is rigid and labor-intensive,and has little balance.The assembly process cannot readily adapt to changes in assembly situations.To address these issues,a collaborative assembly is proposed.Based on the requirements of collaborative assembly,a colored Petri net(CPN)model is proposed to analyze the performance of the interaction and self-government of robots in collaborative assembly.Also,an artificial potential field based planning algorithm(AFPA)is presented to realize the assembly planning and dynamic interaction of robots in the collaborative assembly of LVEAs.Then an adaptive quantum genetic algorithm(AQGA)is developed to optimize the assembly process.Lastly,taking a two-pole circuit-breaker controller with leakage protection(TPCLP)as an assembly instance,comparative results show that the collaborative assembly is cost-effective and flexible in LVEA assembly.The distribution of resources can also be optimized in the assembly.The assembly robots can interact dynamically with each other to accommodate changes that may occur in the LVEA assembly.展开更多
A wireless signal transmission technology based on acoustic carrier is proposed,which overcomes the limitation of electromagnetic signal shielding and shows great potential for in-site monitoring of sliding electrical...A wireless signal transmission technology based on acoustic carrier is proposed,which overcomes the limitation of electromagnetic signal shielding and shows great potential for in-site monitoring of sliding electrical contact used in gas-insulated switchgear(GIS)/gasinsulated transmission line(GIL).Here,the state parameter of the sliding electrical contact is modulated onto the frequency domain of an ultrasound wave.As a mechanical wave,the ultrasonic wave is immune to electromagnetic shielding,so that it could carry the sensing signal to penetrate the metal shielding layer and transmit to the external terminals of GIS/GIL.The principle and signal modulation process of the acoustic carrier based transmission system have been demonstrated in detail.Both simulation and experiment have been conducted to analyse the system characteristics as well as optimise the system configuration.As a proof-of-concept application,the in situ and on-line monitoring of the thermal rise of a slide electrical contact both in a current loading equivalent model and a prototype of GIS is demonstrated.Experimental results fit well with the physical process,and show a good measurement accuracy of 0.6%and tem-perature sensitivity of 400 Hz/℃.展开更多
基金Supported by the Chinese Academy of Sciences Action Plan for the Development of Western China (No. KZCX2-XB2-13)the Chinese Academy of Sciences Knowledge Innovation Program (No. KSCX2-YW-N-003)the 100 Talents Program of Chinese Academy of Sciences
文摘In order to utilize the wasted saline-sodic soils under shallow groundwater condition, a 3-year field study was carried in a field cropped with Lycium barbarum L. and irrigated by drip irrigation with saline groundwater under the water table depth of 30-40 cm in the northern Yinchuan Plain, China. Effects of cropping duration （one, two, and three years） on soil salinity, soil solution composition, and pH in three adjacent plots were investigated in 2008. Results showed that a high irrigation frequency maintained high soil water potential and subsequently facilitated infiltration and downward movement of water and salt in the crop root zone. Salt accumulated on the edges of the ridges, and soil saturated-paste electrical conductivity （ECe） was higher in the edge. Concentrations of Na^＋, Ca^2＋, Mg^2＋, Cl^-, and SO24^- in the soil increased with the soil depth as did the ECe, while HCO3 and pH had a relative uniform distribution in soil profile. As planting year increased, the ECe and soil salts in the field had a decreasing tendency, while in the root zone they decreased immediately after irrigation and then remained relatively stable in the following growing seasons. HCO3 and pH had little change with the planting year. Results suggested that the application of drip irrigation with saline water could ameliorate saline-sodic soil and provide a relatively feasible soil environment for saline-sodic soils with shallow groundwater.
基金co-supported by the National Natural Science Foundation of China(No.51201182)
文摘Abstract Advanced crack monitoring technique is the cornerstone of aircraft structural health monitoring. To achieve realtime crack monitoring of aircraft metal structures in the course of ser vice, a new crack monitoring method is proposed based on Cu coating sensor and electrical poten tial difference principle. Firstly, insulation treatment process was used to prepare a dielectric layer on structural substrate, such as an anodizing layer on 2AI2T4 aluminum alloy substrate, and then a Cu coating crack monitoring sensor was deposited on the structure fatigue critical parts by pulsed bias arc ion plating technology. Secondly, the damage consistency of the Cu coating sensor and 2A12T4 aluminum alloy substrate was investigated by static tensile experiment and fatigue test. The results show that strain values of the coating sensor and the 2A 12T4 aluminum alloy substrate measured by strain gauges are highly coincident in static tensile experiment and the sensor has excel lent fatigue damage consistency with the substrate. Thirdly, the fatigue performance discrepancy between samples with the coating sensor and original samples was investigated. The result shows that there is no obvious negative influence on the fatigue performance of the 2A12T4 aluminum alloy after preparing the Cu coating sensor on its surface. Finally, crack monitoring experiment was carried out with the Cu coating sensor. The experimental results indicate that the sensor is sensitive to crack, and crack origination and propagation can be monitored effectively through analyzing the change of electrical potential values of the coating sensor.
基金sponsored by the National Major Project(No.2016ZX05014-001)the National Natural Science Foundation of China(No.41172130 and U1403191)the Fundamental Research Funds for the Central Universities(No.2-9-2015-209)
文摘Borehole-to-surface electrical imaging （BSEI） uses a line source and a point source to generate a stable electric field in the ground. In order to study the surface potential of anomalies, three-dimensional forward modeling of point and line sources was conducted by using the finite-difference method and the incomplete Cholesky conjugate gradient （ICCG） method. Then, the damping least square method was used in the 3D inversion of the formation resistivity data. Several geological models were considered in the forward modeling and inversion. The forward modeling results suggest that the potentials generated by the two sources have different surface signatures. The inversion data suggest that the low- resistivity anomaly is outlined better than the high-resistivity anomaly. Moreover, when the point source is under the anomaly, the resistivity anomaly boundaries are better outlined than when using a line source.
基金supported by the National Natural Science Foundation of China(No.52175124)the Zhejiang Provincial Natural Science Foundation of China(No.LZ21E050003)the Fundamental Research Funds for Zhejiang Universities,China(No.RF-C2020004)。
文摘Low-voltage electrical apparatuses(LVEAs)have many workpieces and intricate geometric structures,and the assembly process is rigid and labor-intensive,and has little balance.The assembly process cannot readily adapt to changes in assembly situations.To address these issues,a collaborative assembly is proposed.Based on the requirements of collaborative assembly,a colored Petri net(CPN)model is proposed to analyze the performance of the interaction and self-government of robots in collaborative assembly.Also,an artificial potential field based planning algorithm(AFPA)is presented to realize the assembly planning and dynamic interaction of robots in the collaborative assembly of LVEAs.Then an adaptive quantum genetic algorithm(AQGA)is developed to optimize the assembly process.Lastly,taking a two-pole circuit-breaker controller with leakage protection(TPCLP)as an assembly instance,comparative results show that the collaborative assembly is cost-effective and flexible in LVEA assembly.The distribution of resources can also be optimized in the assembly.The assembly robots can interact dynamically with each other to accommodate changes that may occur in the LVEA assembly.
基金National Natural Science Foundation of China,Grant/Award Number:52107163。
文摘A wireless signal transmission technology based on acoustic carrier is proposed,which overcomes the limitation of electromagnetic signal shielding and shows great potential for in-site monitoring of sliding electrical contact used in gas-insulated switchgear(GIS)/gasinsulated transmission line(GIL).Here,the state parameter of the sliding electrical contact is modulated onto the frequency domain of an ultrasound wave.As a mechanical wave,the ultrasonic wave is immune to electromagnetic shielding,so that it could carry the sensing signal to penetrate the metal shielding layer and transmit to the external terminals of GIS/GIL.The principle and signal modulation process of the acoustic carrier based transmission system have been demonstrated in detail.Both simulation and experiment have been conducted to analyse the system characteristics as well as optimise the system configuration.As a proof-of-concept application,the in situ and on-line monitoring of the thermal rise of a slide electrical contact both in a current loading equivalent model and a prototype of GIS is demonstrated.Experimental results fit well with the physical process,and show a good measurement accuracy of 0.6%and tem-perature sensitivity of 400 Hz/℃.
