China＇s continental deposition basins are characterized by complex geological structures and various reservoir lithologies. Therefore, high precision exploration methods are needed. High density spatial sampling is a...China＇s continental deposition basins are characterized by complex geological structures and various reservoir lithologies. Therefore, high precision exploration methods are needed. High density spatial sampling is a new technology to increase the accuracy of seismic exploration. We briefly discuss point source and receiver technology, analyze the high density spatial sampling in situ method, introduce the symmetric sampling principles presented by Gijs J. O. Vermeer, and discuss high density spatial sampling technology from the point of view of wave field continuity. We emphasize the analysis of the high density spatial sampling characteristics, including the high density first break advantages for investigation of near surface structure, improving static correction precision, the use of dense receiver spacing at short offsets to increase the effective coverage at shallow depth, and the accuracy of reflection imaging. Coherent noise is not aliased and the noise analysis precision and suppression increases as a result. High density spatial sampling enhances wave field continuity and the accuracy of various mathematical transforms, which benefits wave field separation. Finally, we point out that the difficult part of high density spatial sampling technology is the data processing. More research needs to be done on the methods of analyzing and processing huge amounts of seismic data.展开更多
This fully digital beam position measurement instrument is designed for beam position monitoring and machine research in Shanghai Synchrotron Radiation Facility. The signals received from four position-sensitive detec...This fully digital beam position measurement instrument is designed for beam position monitoring and machine research in Shanghai Synchrotron Radiation Facility. The signals received from four position-sensitive detectors are narrow pulses with a repetition rate up to 499.654 MHz and a pulse width of around 100 ps, and their dynamic range could vary over more than 40 dB in machine research. By the employment of the under-sampling technique based on high-speed high-resolution A/D conversion, all the processing procedure is performed fully by the digital signal processing algorithms integrated in one single Field Programmable Gate Array. This system functions well in the laboratory and commissioning tests, demonstrating a position resolution (at the turn by turn rate of 694 kHz) better than 7 μm over the input amplitude range of -40 dBm to 10 dBm which is well beyond the requirement.展开更多
This paper introduces the design and development of a new computerized data acquisition system for the coal fired magnetohydrodynamical (MHD) electrical power generation experiments. Compared to the previous system, ...This paper introduces the design and development of a new computerized data acquisition system for the coal fired magnetohydrodynamical (MHD) electrical power generation experiments. Compared to the previous system, it has a higher sampling rate and an improved simultaneity performance. It also improves the data collection method and sensor design for the measurement of Faraday voltages and Faraday currents. The system has been successfully used in many regular MHD generator tests. It provides an excellent base for the future research and development of the Coal fired MHD electrical power generation.展开更多
This paper presents main functions of a high voltage,high speed and extensive memory transient measurementequipment and design of associate hardware and software. Thepaper also introduces the hardware design of high s...This paper presents main functions of a high voltage,high speed and extensive memory transient measurementequipment and design of associate hardware and software. Thepaper also introduces the hardware design of high speed hugememory data sampler, explains the know-how of data analysissoftware, program-controlled voltage divider andanti-interference measurement, with which the equipmentperforms excellent on--site.This equipment reallies automatic measurement and satisfiesthe requirement of high voltage digital measurment.展开更多
Fault frequency of catenary is related to meteo-rological conditions. In this work, based on the historical data, catenary fault frequency and weather-related fault rate are introduced to analyse the correlation betwe...Fault frequency of catenary is related to meteo-rological conditions. In this work, based on the historical data, catenary fault frequency and weather-related fault rate are introduced to analyse the correlation between catenary faults and meteorological conditions, and further the effect of meteorological conditions on catenary oper-ation. Moreover, machine learning is used for catenary fault prediction. As with the single decision tree, only a small number of training samples can be classified cor-rectly by each weak classifier, the AdaBoost algorithm is adopted to adjust the weights of misclassified samples and weak classifiers, and train multiple weak classifiers. Finally, the weak classifiers are combined to construct a strong classifier, with which the final prediction result is obtained. In order to validate the prediction method, an example is provided based on the historical data from a railway bureau of China. The result shows that the mapping relation between meteorological conditions and catenary faults can be established accurately by AdaBoost algorithm. The AdaBoost algorithm can accurately predict a catenary fault if the meteorological conditions are provided.展开更多
针对国内时速600 k m高速磁浮工程化装备的成功研制,其牵引供电系统正面临动态响应实时优化、多物理场耦合分析及全生命周期可靠性管理等技术挑战。以数字孪生技术为切入点,首先阐述数字孪生内涵以及在轨道交通及电力装备系统中的应用现...针对国内时速600 k m高速磁浮工程化装备的成功研制,其牵引供电系统正面临动态响应实时优化、多物理场耦合分析及全生命周期可靠性管理等技术挑战。以数字孪生技术为切入点,首先阐述数字孪生内涵以及在轨道交通及电力装备系统中的应用现状;接着深入剖析磁浮牵引供电系统实现数字孪生需要攻克的关键技术瓶颈,研究依托时速600 k m高速磁浮牵引供电系统,构建数字孪生平台框架,详述搭建方法及具体成果,最后探讨数字孪生技术在高速磁浮领域的工程化应用前景及技术挑战,为下一代智能磁浮系统提供关键技术支撑。展开更多
描述了一种基于现场可编程逻辑阵列(FPGA)的高速核信号采集系统的设计方案。FPGA作为控制核心,实现对高速Analog-to-Digital Converter(ADC)和Universal Serial Bus(USB)的逻辑控制和数字信号的采样、滤波、甄别、存储、传输处理,并使...描述了一种基于现场可编程逻辑阵列(FPGA)的高速核信号采集系统的设计方案。FPGA作为控制核心,实现对高速Analog-to-Digital Converter(ADC)和Universal Serial Bus(USB)的逻辑控制和数字信号的采样、滤波、甄别、存储、传输处理,并使用异步First In First Out(FIFO)实现ADC数据采集模块和USB数据传输模块2个不同时钟域之间的数据传输,提高数据的吞吐率。最后利用上位机软件进行数据处理和绘图显示。测试结果表明,该系统能够实现核信号的实时、高效采集。展开更多
文摘China＇s continental deposition basins are characterized by complex geological structures and various reservoir lithologies. Therefore, high precision exploration methods are needed. High density spatial sampling is a new technology to increase the accuracy of seismic exploration. We briefly discuss point source and receiver technology, analyze the high density spatial sampling in situ method, introduce the symmetric sampling principles presented by Gijs J. O. Vermeer, and discuss high density spatial sampling technology from the point of view of wave field continuity. We emphasize the analysis of the high density spatial sampling characteristics, including the high density first break advantages for investigation of near surface structure, improving static correction precision, the use of dense receiver spacing at short offsets to increase the effective coverage at shallow depth, and the accuracy of reflection imaging. Coherent noise is not aliased and the noise analysis precision and suppression increases as a result. High density spatial sampling enhances wave field continuity and the accuracy of various mathematical transforms, which benefits wave field separation. Finally, we point out that the difficult part of high density spatial sampling technology is the data processing. More research needs to be done on the methods of analyzing and processing huge amounts of seismic data.
基金Supported by Knowledge Innovation Program of The Chinese Academy of Sciences (KJCX2-YW-N27)the National Natural Science Foundation of China (10875119)100 Talents Program of The Chinese Academy of Sciences
文摘This fully digital beam position measurement instrument is designed for beam position monitoring and machine research in Shanghai Synchrotron Radiation Facility. The signals received from four position-sensitive detectors are narrow pulses with a repetition rate up to 499.654 MHz and a pulse width of around 100 ps, and their dynamic range could vary over more than 40 dB in machine research. By the employment of the under-sampling technique based on high-speed high-resolution A/D conversion, all the processing procedure is performed fully by the digital signal processing algorithms integrated in one single Field Programmable Gate Array. This system functions well in the laboratory and commissioning tests, demonstrating a position resolution (at the turn by turn rate of 694 kHz) better than 7 μm over the input amplitude range of -40 dBm to 10 dBm which is well beyond the requirement.
文摘This paper introduces the design and development of a new computerized data acquisition system for the coal fired magnetohydrodynamical (MHD) electrical power generation experiments. Compared to the previous system, it has a higher sampling rate and an improved simultaneity performance. It also improves the data collection method and sensor design for the measurement of Faraday voltages and Faraday currents. The system has been successfully used in many regular MHD generator tests. It provides an excellent base for the future research and development of the Coal fired MHD electrical power generation.
文摘This paper presents main functions of a high voltage,high speed and extensive memory transient measurementequipment and design of associate hardware and software. Thepaper also introduces the hardware design of high speed hugememory data sampler, explains the know-how of data analysissoftware, program-controlled voltage divider andanti-interference measurement, with which the equipmentperforms excellent on--site.This equipment reallies automatic measurement and satisfiesthe requirement of high voltage digital measurment.
基金supported by the Scientific and Technological Research and Development Program of China Railway Corporation under Grant N2018G023by the Science and Technology Projects of Sichuan Province under Grants 2018RZ0075
文摘Fault frequency of catenary is related to meteo-rological conditions. In this work, based on the historical data, catenary fault frequency and weather-related fault rate are introduced to analyse the correlation between catenary faults and meteorological conditions, and further the effect of meteorological conditions on catenary oper-ation. Moreover, machine learning is used for catenary fault prediction. As with the single decision tree, only a small number of training samples can be classified cor-rectly by each weak classifier, the AdaBoost algorithm is adopted to adjust the weights of misclassified samples and weak classifiers, and train multiple weak classifiers. Finally, the weak classifiers are combined to construct a strong classifier, with which the final prediction result is obtained. In order to validate the prediction method, an example is provided based on the historical data from a railway bureau of China. The result shows that the mapping relation between meteorological conditions and catenary faults can be established accurately by AdaBoost algorithm. The AdaBoost algorithm can accurately predict a catenary fault if the meteorological conditions are provided.
文摘针对国内时速600 k m高速磁浮工程化装备的成功研制,其牵引供电系统正面临动态响应实时优化、多物理场耦合分析及全生命周期可靠性管理等技术挑战。以数字孪生技术为切入点,首先阐述数字孪生内涵以及在轨道交通及电力装备系统中的应用现状;接着深入剖析磁浮牵引供电系统实现数字孪生需要攻克的关键技术瓶颈,研究依托时速600 k m高速磁浮牵引供电系统,构建数字孪生平台框架,详述搭建方法及具体成果,最后探讨数字孪生技术在高速磁浮领域的工程化应用前景及技术挑战,为下一代智能磁浮系统提供关键技术支撑。
文摘描述了一种基于现场可编程逻辑阵列(FPGA)的高速核信号采集系统的设计方案。FPGA作为控制核心,实现对高速Analog-to-Digital Converter(ADC)和Universal Serial Bus(USB)的逻辑控制和数字信号的采样、滤波、甄别、存储、传输处理,并使用异步First In First Out(FIFO)实现ADC数据采集模块和USB数据传输模块2个不同时钟域之间的数据传输,提高数据的吞吐率。最后利用上位机软件进行数据处理和绘图显示。测试结果表明,该系统能够实现核信号的实时、高效采集。
