An angle trajectory tracking of a 3-DOF （Degree Of Freedom） pneumatic motion platform by the NI Compact RIO control system was investigated. In this study, the positions of moving platform are changed by extension o...An angle trajectory tracking of a 3-DOF （Degree Of Freedom） pneumatic motion platform by the NI Compact RIO control system was investigated. In this study, the positions of moving platform are changed by extension or shortening of the three pneumatic cylinders. The response of pneumatic cylinder is relatively slow for motor actuator and can get a good single-axis trajectory control by traditional P controller, but the trajectory tracking of platform has a delay phenomenon for angle instantly larger change. To improve this situation in this study, Fuzzy system is used in the trajectory pre-compensation. By the angle changes and the angle rates of change in Fuzzy systems, the value of a pre-compensation output and each axis value are calculated using the Jacobian matrix after compensation in each axis. Through experiments, this Fuzzy pre-compensation method is proved to be able to improve the delay situation of angle trajectory tracking.展开更多
The performance of inclined pile group embedded in consolidating soil under surcharge load was investigated by experiment in comparison with vertical pile group and single pile under the same conditions; dragload, dow...The performance of inclined pile group embedded in consolidating soil under surcharge load was investigated by experiment in comparison with vertical pile group and single pile under the same conditions; dragload, downdrag, and layered soil settlement were measured. A three-dimensional numerical model was built via FLAC3D software, and verified by the experimental results. Influence factors, such as consolidation time, pile spacing, and pile tilt angle were analyzed. The results show that dragload of inclined pile group increases with the increase of consolidation time and pile spacing or the decrease of pile tilt angle. Downdrag of inclined pile group increases with the increase of consolidation time, pile spacing and pile tilt angle.展开更多
To wirelessly obtain the accurate location and orientation of an objective and exert an appropriate guidance for the objective, a feasible approach is to enclose a small rectangular permanent mag- net in the objective...To wirelessly obtain the accurate location and orientation of an objective and exert an appropriate guidance for the objective, a feasible approach is to enclose a small rectangular permanent mag- net in the objective. The magnetic field, produced by the rectangular magnet can be detected by magnetic sensors outside the objective. With these sensor data, the 3D localization and 3D orienta- tion parameters can be computed based on the mathematic model of the rectangular magnet magnetic field. In this 6D localization and orientation system, we first obtain 5D parameters of the objective by dipole model, then based on these parameters we can obtain 6D parameters by the model of rectangular magnet magnetic field using the particle swarm optimization （PSO） algorithm. Simulation experiments show that the proposed approach achieves ~ood performance.展开更多
We investigate the position dependent spontaneous emission spectra of a A-type three-level atom with one transition coupled to the free vacuum reservoir and the other one coupled to a double-band photonic band gap res...We investigate the position dependent spontaneous emission spectra of a A-type three-level atom with one transition coupled to the free vacuum reservoir and the other one coupled to a double-band photonic band gap reservoir with a defect mode in the band gap. It is shown that, for the atom at the defect location, we have a two-peak spectrum with a wide dark line due to the strong coupling between the atom and the defect mode. While, when the atom is far from the defect location （or in the absence of the defect mode）, the spectrum has three peaks with two dark lines due to the coupling between the atom and the photonic band gap reservoir with the largest density of states near the band edges. On the other hand, we have a four-peak spectrum for the atom at the space in between. Moreover, the average spontaneous emission spectra of the atoms uniformly embedded in high dielectric or low dielectric regions are described. It is shown that the atoms embedded in high （low） dielectric regions far from the defect location, effectively couple to the modes of the lower （upper） photonic band. However, the atoms embedded in high dielectric or low dielectric regions at the defect location, are coupled mainly to the defect modes. While, the atoms uniformly embedded in high （low） dielectric regions with a normal distance from the defect location, are coupled to both of defect and lower （upper） photonic band modes.展开更多
A near-triangular embedding is an embedded graph into some surface whose all but one facial walks are 3-gons. In this paper we show that if a graph G is a triangulation of an orientable surface Sh, then G has a near-t...A near-triangular embedding is an embedded graph into some surface whose all but one facial walks are 3-gons. In this paper we show that if a graph G is a triangulation of an orientable surface Sh, then G has a near-triangular embedding into Sk for k=h, h＋1,...1,[β（G）/2], where β（G） is the Betti number of G.展开更多
We report on the ice-templated preparation and sodium storage of ultrasmall SnO2 nanoparticles （3--4 nm） embedded in three-dimensional （3D） graphene （SnO2@3DG）. SnO2@3DG was fabricated by hydrothermal assembly w...We report on the ice-templated preparation and sodium storage of ultrasmall SnO2 nanoparticles （3--4 nm） embedded in three-dimensional （3D） graphene （SnO2@3DG）. SnO2@3DG was fabricated by hydrothermal assembly with ice-templated 3DG and a tin source. The structure and morphology analyses showed that 3DG has an interconnected porous architecture with a large pore volume of 0.578 cm^3·g^-1 and a high surface area of 470.5 m^2·g^-1. In comparison, SnO2@3DG exhibited a pore volume of 0.321 cmg.g^-1 and a surface area of 237.7 m^2·g^-1 with a homogeneous distribution of ultrasmall SnO2 nanoparticles in a 3DG network. SnO2@3DG showed a discharge capacity of 1,155 mA-h·g^-1 in the initial cycle, a reversible capacity of 432 mA·h·g^-1 after 200 cycles at 100 mA·g^-1 （with capacity retention of 85.7% relative to that in the second cycle）, and a discharge capacity of 210 mAh·g^-1 at a high rate of 800 mA·g^-1 This is due to the high distribution of SnO2 nanoparticles in the 3DG network and the enhanced facilitation of electron/ion transport in the electrode.展开更多
The symmetries of surfaces which can be embedded into the symmetries of the 3-dimensional Euclidean space R3 are easier to feel by human＇s intuition. We give the maximum order of finite group actions on （R3 E） amon...The symmetries of surfaces which can be embedded into the symmetries of the 3-dimensional Euclidean space R3 are easier to feel by human＇s intuition. We give the maximum order of finite group actions on （R3 E） among all possible embedded closed/bordered surfaces with given geometric/algebraic genus greater than 1 in R3. We also identify the topological types of the bordered surfaces realizing the maximum order, and findsimple representative embeddings for such surfaces.展开更多
文摘An angle trajectory tracking of a 3-DOF （Degree Of Freedom） pneumatic motion platform by the NI Compact RIO control system was investigated. In this study, the positions of moving platform are changed by extension or shortening of the three pneumatic cylinders. The response of pneumatic cylinder is relatively slow for motor actuator and can get a good single-axis trajectory control by traditional P controller, but the trajectory tracking of platform has a delay phenomenon for angle instantly larger change. To improve this situation in this study, Fuzzy system is used in the trajectory pre-compensation. By the angle changes and the angle rates of change in Fuzzy systems, the value of a pre-compensation output and each axis value are calculated using the Jacobian matrix after compensation in each axis. Through experiments, this Fuzzy pre-compensation method is proved to be able to improve the delay situation of angle trajectory tracking.
基金Supported by National Natural Science Foundation of China (No. 51008116)State Key Laboratory of Coastal and Offshore Engineering (No. LP1014)+1 种基金Fundamental Research Funds for the Central Universities (No. 2009B14514)China Postdoctoral Science Foundation (No. 20090461062)
文摘The performance of inclined pile group embedded in consolidating soil under surcharge load was investigated by experiment in comparison with vertical pile group and single pile under the same conditions; dragload, downdrag, and layered soil settlement were measured. A three-dimensional numerical model was built via FLAC3D software, and verified by the experimental results. Influence factors, such as consolidation time, pile spacing, and pile tilt angle were analyzed. The results show that dragload of inclined pile group increases with the increase of consolidation time and pile spacing or the decrease of pile tilt angle. Downdrag of inclined pile group increases with the increase of consolidation time, pile spacing and pile tilt angle.
文摘To wirelessly obtain the accurate location and orientation of an objective and exert an appropriate guidance for the objective, a feasible approach is to enclose a small rectangular permanent mag- net in the objective. The magnetic field, produced by the rectangular magnet can be detected by magnetic sensors outside the objective. With these sensor data, the 3D localization and 3D orienta- tion parameters can be computed based on the mathematic model of the rectangular magnet magnetic field. In this 6D localization and orientation system, we first obtain 5D parameters of the objective by dipole model, then based on these parameters we can obtain 6D parameters by the model of rectangular magnet magnetic field using the particle swarm optimization （PSO） algorithm. Simulation experiments show that the proposed approach achieves ~ood performance.
文摘We investigate the position dependent spontaneous emission spectra of a A-type three-level atom with one transition coupled to the free vacuum reservoir and the other one coupled to a double-band photonic band gap reservoir with a defect mode in the band gap. It is shown that, for the atom at the defect location, we have a two-peak spectrum with a wide dark line due to the strong coupling between the atom and the defect mode. While, when the atom is far from the defect location （or in the absence of the defect mode）, the spectrum has three peaks with two dark lines due to the coupling between the atom and the photonic band gap reservoir with the largest density of states near the band edges. On the other hand, we have a four-peak spectrum for the atom at the space in between. Moreover, the average spontaneous emission spectra of the atoms uniformly embedded in high dielectric or low dielectric regions are described. It is shown that the atoms embedded in high （low） dielectric regions far from the defect location, effectively couple to the modes of the lower （upper） photonic band. However, the atoms embedded in high dielectric or low dielectric regions at the defect location, are coupled mainly to the defect modes. While, the atoms uniformly embedded in high （low） dielectric regions with a normal distance from the defect location, are coupled to both of defect and lower （upper） photonic band modes.
基金the National Natural Science Foundation of China (19831080)Shanghai City Fundation of Selected Academic Research (04JC14031)
文摘A near-triangular embedding is an embedded graph into some surface whose all but one facial walks are 3-gons. In this paper we show that if a graph G is a triangulation of an orientable surface Sh, then G has a near-triangular embedding into Sk for k=h, h＋1,...1,[β（G）/2], where β（G） is the Betti number of G.
文摘We report on the ice-templated preparation and sodium storage of ultrasmall SnO2 nanoparticles （3--4 nm） embedded in three-dimensional （3D） graphene （SnO2@3DG）. SnO2@3DG was fabricated by hydrothermal assembly with ice-templated 3DG and a tin source. The structure and morphology analyses showed that 3DG has an interconnected porous architecture with a large pore volume of 0.578 cm^3·g^-1 and a high surface area of 470.5 m^2·g^-1. In comparison, SnO2@3DG exhibited a pore volume of 0.321 cmg.g^-1 and a surface area of 237.7 m^2·g^-1 with a homogeneous distribution of ultrasmall SnO2 nanoparticles in a 3DG network. SnO2@3DG showed a discharge capacity of 1,155 mA-h·g^-1 in the initial cycle, a reversible capacity of 432 mA·h·g^-1 after 200 cycles at 100 mA·g^-1 （with capacity retention of 85.7% relative to that in the second cycle）, and a discharge capacity of 210 mAh·g^-1 at a high rate of 800 mA·g^-1 This is due to the high distribution of SnO2 nanoparticles in the 3DG network and the enhanced facilitation of electron/ion transport in the electrode.
基金supported by National Natural Science Foundation of China(Grant Nos.11371034 and 11501239)
文摘The symmetries of surfaces which can be embedded into the symmetries of the 3-dimensional Euclidean space R3 are easier to feel by human＇s intuition. We give the maximum order of finite group actions on （R3 E） among all possible embedded closed/bordered surfaces with given geometric/algebraic genus greater than 1 in R3. We also identify the topological types of the bordered surfaces realizing the maximum order, and findsimple representative embeddings for such surfaces.
