Acoustic Barkhausen Emission (ABE) and Electromagnetic Barkhausen Emission (EBE) have been measured. Explanations of the response of nickel to an applied magnetic field are considered using energy density diagrams and...Acoustic Barkhausen Emission (ABE) and Electromagnetic Barkhausen Emission (EBE) have been measured. Explanations of the response of nickel to an applied magnetic field are considered using energy density diagrams and critical fields deduced using Kersten's modified theory. These theoretical models are correlated with ABE and EBE measurements, providing further confirmation of the origins of ABE being non-180° domain wall motion. This paper also shows that the motion of domain walls, on increasing the magnetising fields from saturation to satu -ration, follows the sequence of 71°-180° - 109°. Values of critical fields correponding to 71°, 180° and 109° wall motions in nickel are determined using these techniques .展开更多
The evolution of point bars in changing sections of a downstream tidal current limit is periodic. Accordingly, assessing the critical morphology and hydrodynamic characteristics of point bar scour and the sediment tra...The evolution of point bars in changing sections of a downstream tidal current limit is periodic. Accordingly, assessing the critical morphology and hydrodynamic characteristics of point bar scour and the sediment transport process of scour sediment bodies can support river regulation and waterway maintenance. The frequent scour of point bars in changing sections of tidal current limits within the Yangtze River directly restricts waterway stability. This study examined the Fujiangsha reach of the Yangtze River, hydrological data on sediment transport, and riverbed topography from 1950. The Jingjiang bank tail exhibited an evolutionary cycle(siltation>scour>siltation), with a primary period ranging from 3–6 years. Additionally, certain morphological and dynamic conditions were necessary for scour. The Datong station flow(Q) ranged from 20,000–40,000 m^(3)·s^(-1)for ≥180 days·yr^(-1), enabling the bank silt layers to widen. Scour occurred during flooding and was concentrated in areas 5.0–7.5 km downstream from Ebizui. When Q≥40,000 m^(3)·s^(-1), scouring occurred in the bank middle and lower reaches, whereas Q≥50,000 m^(3)·s^(-1)for >50 consecutive days, scour occurred at the tail as well. Moreover, the volume of the scour shoals increased with the number of high-flow days(≥60,000 m^(3)·s^(-1)). Bottom sand transport mainly occurred in the low-bank zone. Before the project’s second phase, the longitudinal transport of the scouring sand bodies occurred as follows: Jingjiang bank > low bank on the north side of Shuangjiansha > Fubei anabranch. During the second phase, the longitudinal transport route changed to Jingjiang bank > Fubei anabranch. The Jingjiang bank volume was also reduced;thus, its development was controlled. Owing to changes in the longitudinal transport routes, dredging should be conducted in areas where scouring sand bodies are separately transported from the tail, thereby reducing the load of dredging and maintenance for the Fubei anabranch during dry years.展开更多
文摘Acoustic Barkhausen Emission (ABE) and Electromagnetic Barkhausen Emission (EBE) have been measured. Explanations of the response of nickel to an applied magnetic field are considered using energy density diagrams and critical fields deduced using Kersten's modified theory. These theoretical models are correlated with ABE and EBE measurements, providing further confirmation of the origins of ABE being non-180° domain wall motion. This paper also shows that the motion of domain walls, on increasing the magnetising fields from saturation to satu -ration, follows the sequence of 71°-180° - 109°. Values of critical fields correponding to 71°, 180° and 109° wall motions in nickel are determined using these techniques .
基金National Key Research and Development Program of China,No.2021YFB2600500National Natural Science Foundation of China,No.52279066Jiangsu Water Conservancy Science and Technology Project,No.2020001。
文摘The evolution of point bars in changing sections of a downstream tidal current limit is periodic. Accordingly, assessing the critical morphology and hydrodynamic characteristics of point bar scour and the sediment transport process of scour sediment bodies can support river regulation and waterway maintenance. The frequent scour of point bars in changing sections of tidal current limits within the Yangtze River directly restricts waterway stability. This study examined the Fujiangsha reach of the Yangtze River, hydrological data on sediment transport, and riverbed topography from 1950. The Jingjiang bank tail exhibited an evolutionary cycle(siltation>scour>siltation), with a primary period ranging from 3–6 years. Additionally, certain morphological and dynamic conditions were necessary for scour. The Datong station flow(Q) ranged from 20,000–40,000 m^(3)·s^(-1)for ≥180 days·yr^(-1), enabling the bank silt layers to widen. Scour occurred during flooding and was concentrated in areas 5.0–7.5 km downstream from Ebizui. When Q≥40,000 m^(3)·s^(-1), scouring occurred in the bank middle and lower reaches, whereas Q≥50,000 m^(3)·s^(-1)for >50 consecutive days, scour occurred at the tail as well. Moreover, the volume of the scour shoals increased with the number of high-flow days(≥60,000 m^(3)·s^(-1)). Bottom sand transport mainly occurred in the low-bank zone. Before the project’s second phase, the longitudinal transport of the scouring sand bodies occurred as follows: Jingjiang bank > low bank on the north side of Shuangjiansha > Fubei anabranch. During the second phase, the longitudinal transport route changed to Jingjiang bank > Fubei anabranch. The Jingjiang bank volume was also reduced;thus, its development was controlled. Owing to changes in the longitudinal transport routes, dredging should be conducted in areas where scouring sand bodies are separately transported from the tail, thereby reducing the load of dredging and maintenance for the Fubei anabranch during dry years.
