We investigate a four-level superradiant laser whose intensity is proportional to N2 and whose linewidth scales as 1/N2. In the absence of spontaneous emissions, we derive the stationary solutions of the atomic full c...
详细信息
We investigate a four-level superradiant laser whose intensity is proportional to N2 and whose linewidth scales as 1/N2. In the absence of spontaneous emissions, we derive the stationary solutions of the atomic full cooperativity, analyze their stabilities, and find the corresponding irreducible representation based on group U(4). We also investigate the spectra of the phase and amplitude fluctuations of the fields inside and outside the cavity and find that the amplitude fluctuations of the output fields cannot be squeezed in the low-frequency limit, which is completely different from the three-level superradiant laser system. Finally, we consider the stationary solutions corresponding to the partial cooperativity due to the symmetry breaking of U(4) induced by the atomic spontaneous emissions.
Because of strong coupling, nonlinear, and time-varying characteristics, it is difficult to control complex spacecraft. By means of combining with controlled object dynamics and performance requirements, characteristi...
详细信息
Because of strong coupling, nonlinear, and time-varying characteristics, it is difficult to control complex spacecraft. By means of combining with controlled object dynamics and performance requirements, characteristic modeling and control approach is an effective way to solve this problem. Aimed at the flexible satellites described by using characteristic modeling approach, with the help of fuzzy rules, fuzzy dynamic characteristic modeling method and intelligent adaptive controller are designed to control this complex spacecraft. Meanwhile, based on the satellite system simulation platform, we validate the correctness and efficiency of the proposed modeling and control method by comparing with the simulation results of the other similar methods.
In recent years, dynamics model and control of space robotsystem are the hot topics in the research field. In this paper, a new dynamics model and control strategy of space robotic system with a flexible manipulator ...
详细信息
In recent years, dynamics model and control of space robotsystem are the hot topics in the research field. In this paper, a new dynamics model and control strategy of space robotic system with a flexible manipulator and a liquid fuel tank are investigated. Based on Lagrange equation method, the dynamics model of the space robotic system coupling with liquid sloshing, flexibility vibration and base movement is derived. The elastic deflection of the flexible manipulator is described by the assumed mode method and equivalent mechanical model is adopted instead of liquid sloshing under the environment of low-gravity. The inverse dynamics control algorithm combined with PD control method is performed to solve the trajectory tracking problem. Some simulation results are given to verify the effectiveness of the proposed method.
In this work, a schematic model of single-walled silicon nanotube (SWSiNT) devices is presented aimed at advancing the understanding of nano-electronic field. The circuit model of one-dimensional SWSiNT devices is fir...
详细信息
ISBN:
(纸本)9781424435432
In this work, a schematic model of single-walled silicon nanotube (SWSiNT) devices is presented aimed at advancing the understanding of nano-electronic field. The circuit model of one-dimensional SWSiNT devices is firstly proposed. The cutoff frequency of SWSiNT devices is obtained, opening up the possibility of a THz silicon nanotube transistor.
All-optical wavelength conversion is investigated using four wave mixing in silicon waveguides. The influences of nonlinear losses caused by two-photon absorption (TPA) and TPA-induced free-carrier absorption on the c...
All-optical wavelength conversion is investigated using four wave mixing in silicon waveguides. The influences of nonlinear losses caused by two-photon absorption (TPA) and TPA-induced free-carrier absorption on the conversion efficiency and phase-matching condition are analyzed. The conversion bandwidth is tempted to enhance by optimizing the waveguide geometry and using the two-pump regime. And finally an angled-polarization pump is used to realize the polarization-independent wavelength conversion by eliminating the polarization discrepancy between the TE and TM modes.
This paper presents a multi-axis control system of bar tacker. A bar tacker must meet the following requirements: feeding accurately, cutting automatically, needle stopping precisely and quickly, et ac. In order to ac...
详细信息
This paper presents a multi-axis control system of bar tacker. A bar tacker must meet the following requirements: feeding accurately, cutting automatically, needle stopping precisely and quickly, et ac. In order to achieve these functions, multi-thread synchronization control was introduced to ensure the multi-axis collaborative motion. And time-based PI method with velocity feed-forward was used to control the needle stop position. The software of this control system was programmed based on embedded Windows platform. At present this control system has been tested in the factory and the test results show that this method can accurately control the multi-axis motion and produce good sewing patterns. Besides lockstitch bar tacker, this control system can also be applied to other intelligent sewing machines by minor changes and improvement.
To show the validity of swarm robots modeling and control properties influenced by resulting algorithmic parameter settings, particle swarm optimization (PSO) is extended to be tools for applying to swarm robotic sear...
详细信息
Interventional treatment becomes increasingly popular since this technique means substantially less trauma for the patient. By using VTK and ITK to build a plan system, the treatment can be high efficiency. VTK is res...
详细信息
Interventional treatment becomes increasingly popular since this technique means substantially less trauma for the patient. By using VTK and ITK to build a plan system, the treatment can be high efficiency. VTK is responsible for visualization, while ITK takes care of the image segmentation and registration. By combining VTK and ITK, and using Qt as the user interface, an interventional treatment plan system is built. This system has finished several mainly functions, like DICOM data displaying in multi-planar reformation, manual segmentation, semi-automatic segmentation, surface rendering using marching cubes algorithm, volume rendering using volume ray casting algorithm. Also an interventional treatment plan system has been developed based on the medical inspection.
作者:
Lin YeDong WangYe LuFucai LiCentre for Advanced Materials Technology (CAMT)
School of AerospaceMechanical and Mechatronic EngineeringThe University of SydneyNSW 2006Australia State Key Laboratory of Mechanical System and VibrationShanghai Jiao Tong UniversityShanghai 200030People''s Republic of China
This study investigates the effects of temperature fluctuation on identification of damage in complex composite structures, using an inverse algorithm based on interrogation using Shannon entropy or kurtosis analysis ...
详细信息
This study investigates the effects of temperature fluctuation on identification of damage in complex composite structures, using an inverse algorithm based on interrogation using Shannon entropy or kurtosis analysis of captured Lamb wave *** method uses mapping of damage signatures from individual sensing (actuator-sensor) paths to the probability values for the presence of damage at individual grids in the monitoring area enclosed by the piezoelectric actuator/sensor network.
暂无评论