HL-2A tokamak is the first non-circular cross-section tokamak with divertor in China. Apart from boundary transport and SOL study, the HL-2A major subject is to investigate the improvement of confinement with high par...HL-2A tokamak is the first non-circular cross-section tokamak with divertor in China. Apart from boundary transport and SOL study, the HL-2A major subject is to investigate the improvement of confinement with high parameters and a lot of front physics and relevant engineering techniques by use of its special Closed divertor with large volume in China.展开更多
A Fokker-Planck study is carried out for tokamak lower hybrid current drive with considering the wavesent of trappingabsorption in the preeffect situation. This Fokker-Planck code is developed based on FASTFP, and sui...A Fokker-Planck study is carried out for tokamak lower hybrid current drive with considering the wavesent of trappingabsorption in the preeffect situation. This Fokker-Planck code is developed based on FASTFP, and suitable for various auxiliary heating and current drive situations The energy loss mechanism through anomalous transport is modeled by using a suitable loss tenn. In the heating phase, the electron distribution deviates from the Maxwellian clearly,展开更多
The roll contour pattern and variety of work and backup rolls in service and its effect on profile and flatness control performance in 1 700 mm hot strip mill at Wuhan Iron and Steel(Group) Corporation were tested and...The roll contour pattern and variety of work and backup rolls in service and its effect on profile and flatness control performance in 1 700 mm hot strip mill at Wuhan Iron and Steel(Group) Corporation were tested and analyzed by the developed finite element models of different typical roll contours configurations.A rather smooth local work roll contour near strip edges and an increase in rolled length can be obtained by application of long stroke work roll shifting system with conventional work roll contours that is incapable of the crown control.In comparison with the conventional backup and work roll contours configuration,the crown control range by the roll bending force enhances by 12.79% and the roll gap stiffness increases by 25.26% with the developed asymmetry self-compensating work rolls(ASR) and varying contact backup rolls(VCR).A better strip profile and flatness quality,an increase in coil numbers within the rolling campaign and a significant alleviated effect of severe work roll wear contours on performance of edge drop control are achieved by the application of ASR with crown control and wear control ability in downstream stand F5 and VCR in all stands of 1 700 mm hot strip mill.展开更多
The morphology of the gully longitudinal profile （GLP） is an important topographic index of the gully bottom associated with the evolution of the gullies. This index can be used to predict the development trend and ...The morphology of the gully longitudinal profile （GLP） is an important topographic index of the gully bottom associated with the evolution of the gullies. This index can be used to predict the development trend and evaluate the eroded volumes and soil losses by gullying. To depict the morphology of GLP and understand its controlling factors, the Global Positioning System Real-time Kinematic （GPS RTK） and the total station were used to measure the detail points along the gully bottom of 122 gullies at six sites of the Yuanmou dry-hot Valley. Then, nine parameters including length （Lt）, horizontal distance （Dh）, height （H）, vertical erosional area （A）, vertical curvature （Co）, concavity （Ca）, average gradient （Ga）, gully length-gradient index （GL）, normalized gully length-gradient index （Ngl）, were calculated and mapped using CASS, Excel and SPSS. The results showed that this study area is dominated by slightly concave and medium gradient GLPs, and the lithology of most gullies is sandstone and siltstone. Although different types of GLPs appear at different sites, all parameters present a positively skewed distribution. There are relatively strong correlations between several parameters： namely Lt and H, Dh and H, Lt and A, Dh and A, H and GL. Most GLPs, except three, have a best fit of exponential functions with quasi- straight shapes. Soil properties, vegetation coverage, piping erosion and topography are important factors to affect the GLP morphology. This study provides useful insight into the knowledge of GLP morphology and its influential factors that are of critical importance to prevent and control gully erosion.展开更多
The first Chinese Mars exploration will fulfill the goals of ＂orbiting, landing and roving＂ in one mission. This paper briefly describes the process of international Mars exploration and analyzes the development of ...The first Chinese Mars exploration will fulfill the goals of ＂orbiting, landing and roving＂ in one mission. This paper briefly describes the process of international Mars exploration and analyzes the development of Chinese Mars exploration. It focuses on introducing the scientific significance and engineering difficulties of Mars exploration, and provides an overview of the system design of the probe, including the flight profile, the preliminary selection of the landing site, the entry, descent and landing （also known as EDL） process. Four types of key technologies, including telecommunications, autonomous control, the EDL process, and its structure and mechanism, are detailed in this paper. Finally, the paper highlights the expected scientific and engineering results of the mission.展开更多
文摘HL-2A tokamak is the first non-circular cross-section tokamak with divertor in China. Apart from boundary transport and SOL study, the HL-2A major subject is to investigate the improvement of confinement with high parameters and a lot of front physics and relevant engineering techniques by use of its special Closed divertor with large volume in China.
文摘A Fokker-Planck study is carried out for tokamak lower hybrid current drive with considering the wavesent of trappingabsorption in the preeffect situation. This Fokker-Planck code is developed based on FASTFP, and suitable for various auxiliary heating and current drive situations The energy loss mechanism through anomalous transport is modeled by using a suitable loss tenn. In the heating phase, the electron distribution deviates from the Maxwellian clearly,
基金Project(20040311890) supported by the Science and Technology Development Foundation of University of Science and Technology Beijing
文摘The roll contour pattern and variety of work and backup rolls in service and its effect on profile and flatness control performance in 1 700 mm hot strip mill at Wuhan Iron and Steel(Group) Corporation were tested and analyzed by the developed finite element models of different typical roll contours configurations.A rather smooth local work roll contour near strip edges and an increase in rolled length can be obtained by application of long stroke work roll shifting system with conventional work roll contours that is incapable of the crown control.In comparison with the conventional backup and work roll contours configuration,the crown control range by the roll bending force enhances by 12.79% and the roll gap stiffness increases by 25.26% with the developed asymmetry self-compensating work rolls(ASR) and varying contact backup rolls(VCR).A better strip profile and flatness quality,an increase in coil numbers within the rolling campaign and a significant alleviated effect of severe work roll wear contours on performance of edge drop control are achieved by the application of ASR with crown control and wear control ability in downstream stand F5 and VCR in all stands of 1 700 mm hot strip mill.
基金supported by the"National Natural Science Foundation of China(Grant No.41471232)""the Fundamental Research Funds of China West Normal University"(Grant No.16A001)"Ecological Security Key Laboratory of Sichuan Province"(Grant No.ESP201301)
文摘The morphology of the gully longitudinal profile （GLP） is an important topographic index of the gully bottom associated with the evolution of the gullies. This index can be used to predict the development trend and evaluate the eroded volumes and soil losses by gullying. To depict the morphology of GLP and understand its controlling factors, the Global Positioning System Real-time Kinematic （GPS RTK） and the total station were used to measure the detail points along the gully bottom of 122 gullies at six sites of the Yuanmou dry-hot Valley. Then, nine parameters including length （Lt）, horizontal distance （Dh）, height （H）, vertical erosional area （A）, vertical curvature （Co）, concavity （Ca）, average gradient （Ga）, gully length-gradient index （GL）, normalized gully length-gradient index （Ngl）, were calculated and mapped using CASS, Excel and SPSS. The results showed that this study area is dominated by slightly concave and medium gradient GLPs, and the lithology of most gullies is sandstone and siltstone. Although different types of GLPs appear at different sites, all parameters present a positively skewed distribution. There are relatively strong correlations between several parameters： namely Lt and H, Dh and H, Lt and A, Dh and A, H and GL. Most GLPs, except three, have a best fit of exponential functions with quasi- straight shapes. Soil properties, vegetation coverage, piping erosion and topography are important factors to affect the GLP morphology. This study provides useful insight into the knowledge of GLP morphology and its influential factors that are of critical importance to prevent and control gully erosion.
文摘The first Chinese Mars exploration will fulfill the goals of ＂orbiting, landing and roving＂ in one mission. This paper briefly describes the process of international Mars exploration and analyzes the development of Chinese Mars exploration. It focuses on introducing the scientific significance and engineering difficulties of Mars exploration, and provides an overview of the system design of the probe, including the flight profile, the preliminary selection of the landing site, the entry, descent and landing （also known as EDL） process. Four types of key technologies, including telecommunications, autonomous control, the EDL process, and its structure and mechanism, are detailed in this paper. Finally, the paper highlights the expected scientific and engineering results of the mission.
