<strong>Objective:</strong> Explore the rule of autonomic nervous dysfunction in the patients with urination disorder after high level spinal cord injury, and seek a safe, objective and accurate method to ...<strong>Objective:</strong> Explore the rule of autonomic nervous dysfunction in the patients with urination disorder after high level spinal cord injury, and seek a safe, objective and accurate method to evaluate autonomic nervous function. <strong>Patients and Method:</strong> 48 patients with dysuria after cervicothoracic SCI were selected. Before, during and after imaging urodynamic examination with slow filling in supine position, blood pressure and ECG were monitored simultaneously. The symptoms of sweating, shivering, headache, flushing and chills were observed and recorded. The study of the relationship among the changes of blood pressure, heart rate and urodynamic indexes and the above symptoms was analyzed. <strong>Results:</strong> They were divided into three groups: group A (no obvious abnormality), group B (hyperactivity) and group C (hypoactivity) according to their BP, HR and existing the symptoms or not. <strong>Conclusion:</strong> The incidence of autonomic dysfunction in the high level SCI patients with dysuria was very high (79.17%), most of them were hyperactivity, and a few were low function. The changes of SBP and DBP in the hypoactivity group all appeared an increasing and then declining trend, while the change of HR in the low function one was lower than normal and decreased continuously. The main inducements of AD are neurogenic detrusor overactivity, detrusor sphincter dyssynergia, elevated abdominal pressure and abnormal bladder sensitivity. The asymptomatic patients had a higher occurrence rate (43.75%). Only by imaging urodynamic examination with slow filling and synchronous blood pressure monitoring, can autonomic nervous function of the patients be evaluated safely, objectively, early and accurately.展开更多
In order to eliminate the influence of frequency change on real-time voltage acquisition,a low-cost solution of voltage monitoring was proposed using the multi-channel DMA synchronous frequency trace-sampling techniqu...In order to eliminate the influence of frequency change on real-time voltage acquisition,a low-cost solution of voltage monitoring was proposed using the multi-channel DMA synchronous frequency trace-sampling technique.In-chip resources of the designed voltage monitor were fully utilized in hardware design to reduce external devices.The MQX RTOS was used to perform the functional tasks flexibly and efficiently;especially the Ethernet communication applications and USB device connection were realized using its TCP/IP protocol stack and USB driver.In addition,to ensure the safety of electrical records,data statistics and alarm information management were also implemented through the management of the storage in FLASH.The test results show that the voltage monitor designed in this paper has the advantages of accurate measurement,strong resistance to frequency interference and low cost,and can be widely applied in the field of voltage monitoring in distribution networks.展开更多
High-density permanent magnet synchronous motors(PMSMs) are widely used in electric drive systems. However, they are susceptible to temperature influences under complex operating conditions, and prolonged operation at...High-density permanent magnet synchronous motors(PMSMs) are widely used in electric drive systems. However, they are susceptible to temperature influences under complex operating conditions, and prolonged operation at high temperatures can first damage the stator winding insulation, which in turn will damage the windings themselves and cause faults. Therefore, stator temperature monitoring is of crucial importance. This paper summarizes the existing temperature monitoring technologies for stator windings of permanent magnet motors, compares the advantages and disadvantages of various methods to help researchers understand this technology, and analyzes its opportunities and challenges, followed by an outlook.展开更多
Cable-membrane structures have small rigidity and are highly sensitive to wind. Structural health monitoring is necessary to ensure the serviceability and safety of the structure. In this research, the design method o...Cable-membrane structures have small rigidity and are highly sensitive to wind. Structural health monitoring is necessary to ensure the serviceability and safety of the structure. In this research, the design method of a structural health monitoring system is using the characteristics of a cable-membrane structure. Taking the Yueyang Sanhe Airport Terminal as an example, a finite element model is established to determine the critical structural components. Next, the engineering requirements and the framework of the monitoring system are studied based on the results of numerical analysis. The specific implementation of the structural health monitoring is then carried out, which includes sensor selection, installation and wiring. The proposed framework is successfully applied to the monitoring system for the Yueyang Airport terminal building, and the synchronous acquisition of fiber Bragg grating and acceleration sensor signals is implemented in an innovative way. The successful implementation and operation of structural health monitoring will help to guarantee the safety of the cablemembrane structure during its service life.展开更多
Utilizing shaft-speed information to analyse vibration signals is an important method for fault diagnosis and condition monitoring of rotating machineries,especially for those running at variable speeds.However,in man...Utilizing shaft-speed information to analyse vibration signals is an important method for fault diagnosis and condition monitoring of rotating machineries,especially for those running at variable speeds.However,in many cases,shaft-speed information is not always available,for a variety of reasons.Fortunately,in most of the measurements,the shaft-speed information is embedded in the vibration response in many different forms,such as in the format of the fundamental shaft-rotation-frequency response and its harmonics,and the gear-meshing-frequency response and its harmonics,etc.Proper signal processing can be used to extract the shaft instantaneous speed from the measured vibration responses.In existing instantaneous shaft-speed-identification methods,a narrow-bandpass filtering technique is used explicitly or implicitly.In a complex gearbox system,such as that used in a wind turbine,the gear-meshing-response component could be modulated by many other shaft speeds,due to the configuration of the gearbox or due to the existence of component damage.As a result,it is very difficult to isolate a single vibration-response component for instantaneous shaft-speed detection.In this paper,an innovative approach is presented.The instantaneous shaft speed is extracted based on maxima tracking from the vibration-response spectrogram.A numerical integration scheme is employed to obtain the shaft instantaneous phase.Digital-domain synchronous resampling is then applied to the vibration data by using the instantaneous phase information.Due to the nature of noise suppression in the numerical integration,the accuracy of synchronous sampling is greatly improved.This proposed approach demonstrates the feasibility and engineering applicability through a controlled laboratory test case and two field wind-turbine cases.More detailed results and conclusions of this research are presented at the end of this paper.展开更多
在现代畜牧业中,生猪的呼吸心率是评估其健康状态的关键指标之一。因此,开发一种非接触式、高精度的多目标生命体征监测技术对于推动畜牧业的现代化发展具有重要意义。毫米波雷达技术通过发射线性调频连续波(Linear frequency modulated...在现代畜牧业中,生猪的呼吸心率是评估其健康状态的关键指标之一。因此,开发一种非接触式、高精度的多目标生命体征监测技术对于推动畜牧业的现代化发展具有重要意义。毫米波雷达技术通过发射线性调频连续波(Linear frequency modulated continuous wave,LFMCW),能够实现极高的脉冲压缩比,从而显著提升雷达的距离分辨率和目标检测能力。针对现有方法在多目标呼吸心率同步监测能力上的不足,本文提出一种联合机器视觉与毫米波感知的多生猪目标呼吸心率同步监测方法。通过YOLO v8算法识别图像中的生猪目标,有效去除非生猪目标振动源,为毫米波雷达提供先验条件,进而通过LFMCW的相量均值相消算法和二维傅里叶变换方法进行静态目标去除和多目标回波解耦,提取回波信号后,通过带通滤波、短时傅里叶变换、周期性评估指标等方法提取目标呼吸心跳时频图并计算呼吸心率。为了验证该方法的有效性,在养殖场实际场景下进行多次实验,结果表明,该方法对生猪呼吸频率测量的平均相对误差为4.57%,心跳频率平均相对误差为9.26%,同步监测准确率较高且对环境中非目标振动源信号具有一定抗干扰能力。展开更多
异地站点之间需要在广域范围实现时间同步。除了采用卫星授时外,希望借助SDH(Synchronous Digital Hierarchy)网络进行时间同步性能的在线监测。但是广域范围内的SDH网络结构复杂、跳数较多,且大量存在上下行线路不对称的现象,对传统网...异地站点之间需要在广域范围实现时间同步。除了采用卫星授时外,希望借助SDH(Synchronous Digital Hierarchy)网络进行时间同步性能的在线监测。但是广域范围内的SDH网络结构复杂、跳数较多,且大量存在上下行线路不对称的现象,对传统网络时间同步技术提出了挑战。因此,针对广域SDH网络,提出了基于WR PTP(White Rabbit Precision Timing Protocol)技术的链路模型。该模型考虑了SDH网络中存在的各个延时环节及其计算方法,并针对实际网络中存在的不对称链路时延,给出了修正方法,推导了时钟偏差的修正计算公式。同时对于SDH环网中存在的链路倒换问题,给出了工程化解决方法。所提各方法在实际的SDH网络上进行了测试,结果表明,能达到的时间同步误差不超过1μs,可满足广域时间同步及时钟同步性能在线监测的需要。展开更多
文摘<strong>Objective:</strong> Explore the rule of autonomic nervous dysfunction in the patients with urination disorder after high level spinal cord injury, and seek a safe, objective and accurate method to evaluate autonomic nervous function. <strong>Patients and Method:</strong> 48 patients with dysuria after cervicothoracic SCI were selected. Before, during and after imaging urodynamic examination with slow filling in supine position, blood pressure and ECG were monitored simultaneously. The symptoms of sweating, shivering, headache, flushing and chills were observed and recorded. The study of the relationship among the changes of blood pressure, heart rate and urodynamic indexes and the above symptoms was analyzed. <strong>Results:</strong> They were divided into three groups: group A (no obvious abnormality), group B (hyperactivity) and group C (hypoactivity) according to their BP, HR and existing the symptoms or not. <strong>Conclusion:</strong> The incidence of autonomic dysfunction in the high level SCI patients with dysuria was very high (79.17%), most of them were hyperactivity, and a few were low function. The changes of SBP and DBP in the hypoactivity group all appeared an increasing and then declining trend, while the change of HR in the low function one was lower than normal and decreased continuously. The main inducements of AD are neurogenic detrusor overactivity, detrusor sphincter dyssynergia, elevated abdominal pressure and abnormal bladder sensitivity. The asymptomatic patients had a higher occurrence rate (43.75%). Only by imaging urodynamic examination with slow filling and synchronous blood pressure monitoring, can autonomic nervous function of the patients be evaluated safely, objectively, early and accurately.
文摘In order to eliminate the influence of frequency change on real-time voltage acquisition,a low-cost solution of voltage monitoring was proposed using the multi-channel DMA synchronous frequency trace-sampling technique.In-chip resources of the designed voltage monitor were fully utilized in hardware design to reduce external devices.The MQX RTOS was used to perform the functional tasks flexibly and efficiently;especially the Ethernet communication applications and USB device connection were realized using its TCP/IP protocol stack and USB driver.In addition,to ensure the safety of electrical records,data statistics and alarm information management were also implemented through the management of the storage in FLASH.The test results show that the voltage monitor designed in this paper has the advantages of accurate measurement,strong resistance to frequency interference and low cost,and can be widely applied in the field of voltage monitoring in distribution networks.
基金supported by the National Key R&D Program of China (2021YFB2500600)。
文摘High-density permanent magnet synchronous motors(PMSMs) are widely used in electric drive systems. However, they are susceptible to temperature influences under complex operating conditions, and prolonged operation at high temperatures can first damage the stator winding insulation, which in turn will damage the windings themselves and cause faults. Therefore, stator temperature monitoring is of crucial importance. This paper summarizes the existing temperature monitoring technologies for stator windings of permanent magnet motors, compares the advantages and disadvantages of various methods to help researchers understand this technology, and analyzes its opportunities and challenges, followed by an outlook.
基金National Natural Science Foundation of China under Grant Nos.51708088 and 51625802the Foundation for High Level Talent Innovation Support Program of Dalian under Grant No.2017RD03
文摘Cable-membrane structures have small rigidity and are highly sensitive to wind. Structural health monitoring is necessary to ensure the serviceability and safety of the structure. In this research, the design method of a structural health monitoring system is using the characteristics of a cable-membrane structure. Taking the Yueyang Sanhe Airport Terminal as an example, a finite element model is established to determine the critical structural components. Next, the engineering requirements and the framework of the monitoring system are studied based on the results of numerical analysis. The specific implementation of the structural health monitoring is then carried out, which includes sensor selection, installation and wiring. The proposed framework is successfully applied to the monitoring system for the Yueyang Airport terminal building, and the synchronous acquisition of fiber Bragg grating and acceleration sensor signals is implemented in an innovative way. The successful implementation and operation of structural health monitoring will help to guarantee the safety of the cablemembrane structure during its service life.
文摘Utilizing shaft-speed information to analyse vibration signals is an important method for fault diagnosis and condition monitoring of rotating machineries,especially for those running at variable speeds.However,in many cases,shaft-speed information is not always available,for a variety of reasons.Fortunately,in most of the measurements,the shaft-speed information is embedded in the vibration response in many different forms,such as in the format of the fundamental shaft-rotation-frequency response and its harmonics,and the gear-meshing-frequency response and its harmonics,etc.Proper signal processing can be used to extract the shaft instantaneous speed from the measured vibration responses.In existing instantaneous shaft-speed-identification methods,a narrow-bandpass filtering technique is used explicitly or implicitly.In a complex gearbox system,such as that used in a wind turbine,the gear-meshing-response component could be modulated by many other shaft speeds,due to the configuration of the gearbox or due to the existence of component damage.As a result,it is very difficult to isolate a single vibration-response component for instantaneous shaft-speed detection.In this paper,an innovative approach is presented.The instantaneous shaft speed is extracted based on maxima tracking from the vibration-response spectrogram.A numerical integration scheme is employed to obtain the shaft instantaneous phase.Digital-domain synchronous resampling is then applied to the vibration data by using the instantaneous phase information.Due to the nature of noise suppression in the numerical integration,the accuracy of synchronous sampling is greatly improved.This proposed approach demonstrates the feasibility and engineering applicability through a controlled laboratory test case and two field wind-turbine cases.More detailed results and conclusions of this research are presented at the end of this paper.
