We assembled approximately 328 seismic records. The data set was from 4 digitally recording long-period and broadband stations of CDSN. We carried out the inversion based on the partitioned waveform inversion (PWI). I...We assembled approximately 328 seismic records. The data set was from 4 digitally recording long-period and broadband stations of CDSN. We carried out the inversion based on the partitioned waveform inversion (PWI). It partitions the large-scale optimization problem into a number of independent small-scale problems. We adopted surface waveform inversion with an equal block (2((2() discretization in order to acquire the images of shear velocity structure at different depths (from surface to 430 km) in the crust and upper-mantle. The resolution of all these anomalies has been established with (check-board( resolution tests. These results show significant difference in velocity, lithosphere and asthenosphere structure between South China Sea and its adjacent regions.展开更多
Wave driven unmanned surface vehicle(WUSV) is a new concept ocean robot drived by wave energy and solar energy,and it is very suitable for the vast ocean observations with incomparable endurance.Its dynamic modeling i...Wave driven unmanned surface vehicle(WUSV) is a new concept ocean robot drived by wave energy and solar energy,and it is very suitable for the vast ocean observations with incomparable endurance.Its dynamic modeling is very important because it is the theoretical foundation for further study in the WUSV motion control and efficiency analysis.In this work,the multibody system of WUSV was described based on D-H approach.Then,the driving principle was analyzed and the dynamic model of WUSV in longitudinal profile is established by Lagrangian mechanics.Finally,the motion simulation of WUSV and comparative analysis are completed by setting different inputs of sea state.Simulation results show that the WUSV dynamic model can correctly reflect the WUSV longitudinal motion process,and the results are consistent with the wave theory.展开更多
The slow wave structure(SWS)of higher-order depressed magnetically insulated transmission line oscillator(HDMILO)is analyzed rigorously,and the electromagnetic field distribution is derived.High-frequency analysis res...The slow wave structure(SWS)of higher-order depressed magnetically insulated transmission line oscillator(HDMILO)is analyzed rigorously,and the electromagnetic field distribution is derived.High-frequency analysis results reveal that the degeneracy of two degenerate HEM!1 modes is removed by the slot in swS plate and the two degenerate modes split into two modes which polarize perpendicularly.Adjusting the azi-muthal position of the slots destroys longitudinal oscillation condition of higher-order modes.展开更多
To overcome the bulk acoustic wave （BAW）, the triple transit signals and the discontinuous frequency band in the first generation surface acoustic wave＇s （FGSAW＇ s） wavelet device, the full transfer multistrip c...To overcome the bulk acoustic wave （BAW）, the triple transit signals and the discontinuous frequency band in the first generation surface acoustic wave＇s （FGSAW＇ s） wavelet device, the full transfer multistrip coupler （MSC） is applied to implement wavelet device, and a novel structure of the second generation surface acoustic wave＇s （SGSAW＇s） wavelet device is proposed. In the SGSAW＇ s wavelet device, the BAW is separated and eliminated in different acoustic propagating tracks, and the triple transit signal is suppressed. For arbitrary wavelet scale device, the center frequency is three times the radius of frequency band, which ensures that the frequency band of the SGSAW＇s wavelet device is continuous, and avoids losing signals caused by the discontinuation of frequency band. Experimental result confirms that the BAW suppression, ripples in band, receiving loss and insertion loss of the SGSAW＇ s wavelet device are remarkably improved compared with those of the FGSAW＇ s wavelet device.展开更多
We estimated crustal v p/ v s ratio of Tibetan Plateau by combined inversion of Love and Rayleigh wave dispersion data. It is developed by us that the joint inversion methods using both Love and Rayleigh wave dispersi...We estimated crustal v p/ v s ratio of Tibetan Plateau by combined inversion of Love and Rayleigh wave dispersion data. It is developed by us that the joint inversion methods using both Love and Rayleigh wave dispersion data. Thickness and S\|wave velocity of each sub layer are taken from Love wave dispersion data, then P\|wave velocity structure was deduced using Rayleigh wave dispersion data. Densities of sub layers were estimated by the empirical relationships between seismic velocity and rock density. Having S\| and P\|wave velocities, v p/ v s ratio is calculated for each sub layer. Six sub layers in crust of Tibetan Plateau has been identified, which are 0～8km, 8～30km, 30～40km, 40～62km, 62～68km and 68～75km respectively. The S\|wave velocity structure of the Plateau is 3 13, 3 32, 3 15, 3 92, 3 45 and 3 87 km/s for each sub layer; and P\|wave velocities are 6 00, 6 10, 5 72, 6 35, 6 78 and 6 64km/s respectively v p/ v s ratios in sub layers are 1 92, 1 84, 1 82, 1 62, 1 96 and 1 72; and corresponding Poisson ratios are 0 31, 0 29, 0 28, 0 19, 0 32 and 0 24. Our result on Poisson ratios of Tibetan crust was supported by seismic waveform modelling by Rodgers and Schwartz (1998).展开更多
为提升随机路面与局部脉冲激励路面下的悬架平顺性,提出语义分割路面识别的主动悬架显式模型预测控制(Explicit Model Predict Control,EMPC)方法。建立2自由度主动悬架动力学模型;搭建基于空洞空间金字塔池化的DeepLabV3语义分割路面...为提升随机路面与局部脉冲激励路面下的悬架平顺性,提出语义分割路面识别的主动悬架显式模型预测控制(Explicit Model Predict Control,EMPC)方法。建立2自由度主动悬架动力学模型;搭建基于空洞空间金字塔池化的DeepLabV3语义分割路面识别网络,对网络进行训练及验证;设计基于路面识别的主动悬架EMPC控制策略,将悬架动力学模型转化为预测模型,确定代价函数和约束条件,根据路面识别结果匹配代价函数最优加权权重;离线划分系统状态参数区域,求解各状态分区内系统的最优控制律;在随机路面和脉冲路面下,将所设计的控制策略与被动悬架、线性二次高斯控制(Linear-quadratic-gaussian Control,LQG)进行仿真分析对比。相较于LQG控制,基于路面识别的主动悬架EMPC控制策略可在随机路面下改善悬架性能,且在脉冲路面下对悬架的调节时间降低20%以上,悬架的平顺性得到有效提升。展开更多
基金State Natural Scientific Foundation (49734150) and National High Performance Computation Foundation.
文摘We assembled approximately 328 seismic records. The data set was from 4 digitally recording long-period and broadband stations of CDSN. We carried out the inversion based on the partitioned waveform inversion (PWI). It partitions the large-scale optimization problem into a number of independent small-scale problems. We adopted surface waveform inversion with an equal block (2((2() discretization in order to acquire the images of shear velocity structure at different depths (from surface to 430 km) in the crust and upper-mantle. The resolution of all these anomalies has been established with (check-board( resolution tests. These results show significant difference in velocity, lithosphere and asthenosphere structure between South China Sea and its adjacent regions.
基金Project(2012-Z05)supported by the State Key Laboratory of Robotics,ChinaProjects(61233013,51179183)supported by the National Natural Science Foundation of China
文摘Wave driven unmanned surface vehicle(WUSV) is a new concept ocean robot drived by wave energy and solar energy,and it is very suitable for the vast ocean observations with incomparable endurance.Its dynamic modeling is very important because it is the theoretical foundation for further study in the WUSV motion control and efficiency analysis.In this work,the multibody system of WUSV was described based on D-H approach.Then,the driving principle was analyzed and the dynamic model of WUSV in longitudinal profile is established by Lagrangian mechanics.Finally,the motion simulation of WUSV and comparative analysis are completed by setting different inputs of sea state.Simulation results show that the WUSV dynamic model can correctly reflect the WUSV longitudinal motion process,and the results are consistent with the wave theory.
文摘The slow wave structure(SWS)of higher-order depressed magnetically insulated transmission line oscillator(HDMILO)is analyzed rigorously,and the electromagnetic field distribution is derived.High-frequency analysis results reveal that the degeneracy of two degenerate HEM!1 modes is removed by the slot in swS plate and the two degenerate modes split into two modes which polarize perpendicularly.Adjusting the azi-muthal position of the slots destroys longitudinal oscillation condition of higher-order modes.
基金This project was supported by the National Natural Science Foundation of China (60476037 ,60176020) and the Doc-toral Foundation of the Ministry of Education of China (20020698014)
文摘To overcome the bulk acoustic wave （BAW）, the triple transit signals and the discontinuous frequency band in the first generation surface acoustic wave＇s （FGSAW＇ s） wavelet device, the full transfer multistrip coupler （MSC） is applied to implement wavelet device, and a novel structure of the second generation surface acoustic wave＇s （SGSAW＇s） wavelet device is proposed. In the SGSAW＇ s wavelet device, the BAW is separated and eliminated in different acoustic propagating tracks, and the triple transit signal is suppressed. For arbitrary wavelet scale device, the center frequency is three times the radius of frequency band, which ensures that the frequency band of the SGSAW＇s wavelet device is continuous, and avoids losing signals caused by the discontinuation of frequency band. Experimental result confirms that the BAW suppression, ripples in band, receiving loss and insertion loss of the SGSAW＇ s wavelet device are remarkably improved compared with those of the FGSAW＇ s wavelet device.
文摘We estimated crustal v p/ v s ratio of Tibetan Plateau by combined inversion of Love and Rayleigh wave dispersion data. It is developed by us that the joint inversion methods using both Love and Rayleigh wave dispersion data. Thickness and S\|wave velocity of each sub layer are taken from Love wave dispersion data, then P\|wave velocity structure was deduced using Rayleigh wave dispersion data. Densities of sub layers were estimated by the empirical relationships between seismic velocity and rock density. Having S\| and P\|wave velocities, v p/ v s ratio is calculated for each sub layer. Six sub layers in crust of Tibetan Plateau has been identified, which are 0～8km, 8～30km, 30～40km, 40～62km, 62～68km and 68～75km respectively. The S\|wave velocity structure of the Plateau is 3 13, 3 32, 3 15, 3 92, 3 45 and 3 87 km/s for each sub layer; and P\|wave velocities are 6 00, 6 10, 5 72, 6 35, 6 78 and 6 64km/s respectively v p/ v s ratios in sub layers are 1 92, 1 84, 1 82, 1 62, 1 96 and 1 72; and corresponding Poisson ratios are 0 31, 0 29, 0 28, 0 19, 0 32 and 0 24. Our result on Poisson ratios of Tibetan crust was supported by seismic waveform modelling by Rodgers and Schwartz (1998).
文摘为提升随机路面与局部脉冲激励路面下的悬架平顺性,提出语义分割路面识别的主动悬架显式模型预测控制(Explicit Model Predict Control,EMPC)方法。建立2自由度主动悬架动力学模型;搭建基于空洞空间金字塔池化的DeepLabV3语义分割路面识别网络,对网络进行训练及验证;设计基于路面识别的主动悬架EMPC控制策略,将悬架动力学模型转化为预测模型,确定代价函数和约束条件,根据路面识别结果匹配代价函数最优加权权重;离线划分系统状态参数区域,求解各状态分区内系统的最优控制律;在随机路面和脉冲路面下,将所设计的控制策略与被动悬架、线性二次高斯控制(Linear-quadratic-gaussian Control,LQG)进行仿真分析对比。相较于LQG控制,基于路面识别的主动悬架EMPC控制策略可在随机路面下改善悬架性能,且在脉冲路面下对悬架的调节时间降低20%以上,悬架的平顺性得到有效提升。
