The quality of the stator winding coil directly affects the performance of the motor.A dual-camera online machine vision detection method to detect whether the coil leads and winding regions were qualified was designe...The quality of the stator winding coil directly affects the performance of the motor.A dual-camera online machine vision detection method to detect whether the coil leads and winding regions were qualified was designed.A vision detection platform was designed to capture individual winding images,and an image processing algorithm was used for image pre-processing,template matching and positioning of the coil lead area to set up a coordinate system.After eliminating image noise by Blob analysis,the improved Canny algorithm was used to detect the location of the coil lead paint stripped region,and the time was reduced by about half compared to the Canny algorithm.The coil winding region was trained with the ShuffleNet V2-YOLOv5s model for the dataset,and the detect file was converted to the Open Neural Network Exchange(ONNX)model for the detection of winding cross features with an average accuracy of 99.0%.The software interface of the detection system was designed to perform qualified discrimination tests on the workpieces,and the detection data were recorded and statistically analyzed.The results showed that the stator winding coil qualified discrimination accuracy reached 96.2%,and the average detection time of a single workpiece was about 300 ms,while YOLOv5s took less than 30 ms.展开更多
The characteristic features of operation in a pulsed regime of bifilar Cooper and Tesla coils during magnetic pulse processing and heating of the environment are considered using the dependence of the maximum amplitud...The characteristic features of operation in a pulsed regime of bifilar Cooper and Tesla coils during magnetic pulse processing and heating of the environment are considered using the dependence of the maximum amplitude at the leading edge of the magnetic pulse <img src="Edit_0a8c724d-3163-470b-b05b-c54ef85a7d58.bmp" alt="" /> on its time duration <em>τ</em>. The spatial distribution of the magnetic induction lines <em><strong>B</strong></em> inside and around the Cooper coil is given, where, unlike the Tesla coil, the maximum values of <em><strong>B</strong></em> arise in the extreme planes of the coil, and its central plane is zero. The defining advantages of new methods of magnetic pulse processing and heating of the environment are considered: the dependence <img src="Edit_8bc48965-e6f8-4005-b1fd-5868944e6862.bmp" alt="" /> at <em>τ</em> → 0;the exchange of energy between the magnetic pulse and the environment;periodic sequence of series of unipolar magnetic pulses at various processing modes. It is shown that 1) for electric fields<em> E<sup>out</sup></em> = 10<sup>10</sup> – 10<sup>12</sup>V/m, arising at the leading edge of a magnetic pulse with duration 10<sup>-5</sup> – 10<sup>-7</sup> s, in the deformation fractal space the electrodynamics of these fields is nonlinear;2) inside the Tesla coil, in the package of conducting tapes and tubes, the pumping energy from the pulsed field <em>E<sup>out</sup></em><sup> </sup>is mainly dissipated in the skin layer in the form of refractory coatings and heats the environment at all stages of plastic deformation of workpieces and heating elements up to the collapse of unstable microcracks. The coefficient of conversion of the pump energy in the pulsed regime with respect to the constant current regime is found.展开更多
For a practical superconducting quantum interference device（SQUID） based measurement system,the Tesla/volt coefficient must be accurately calibrated.In this paper,we propose a highly efficient method of calibrating ...For a practical superconducting quantum interference device（SQUID） based measurement system,the Tesla/volt coefficient must be accurately calibrated.In this paper,we propose a highly efficient method of calibrating a SQUID magnetometer system using three orthogonal Helmholtz coils.The Tesla/volt coefficient is regarded as the magnitude of a vector pointing to the normal direction of the pickup coil.By applying magnetic fields through a three-dimensional Helmholtz coil,the Tesla/volt coefficient can be directly calculated from magnetometer responses to the three orthogonally applied magnetic fields.Calibration with alternating current（AC） field is normally used for better signal-to-noise ratio in noisy urban environments and the results are compared with the direct current（DC） calibration to avoid possible effects due to eddy current.In our experiment,a calibration relative error of about 6.89 × 10-4is obtained,and the error is mainly caused by the non-orthogonality of three axes of the Helmholtz coils.The method does not need precise alignment of the magnetometer inside the Helmholtz coil.It can be used for the multichannel magnetometer system calibration effectively and accurately.展开更多
AIM:To evaluate different promising magnetic resonance imaging(MRI) methods at 7.0 Tesla(T) for the pre-stereotactic visualization of the zona incerta(ZI).METHODS:Two neuroradiologists qualitatively and quantitatively...AIM:To evaluate different promising magnetic resonance imaging(MRI) methods at 7.0 Tesla(T) for the pre-stereotactic visualization of the zona incerta(ZI).METHODS:Two neuroradiologists qualitatively and quantitatively examined T2-turbo spin-echo(T2-TSE),T1-weighted gradient-echo,as well as FLASH2D-T2Star and susceptibility-weighted imaging(SWI) for the visualization of the ZI at 7.0 T MRI.Delineation and image quality for the ZI were independently examined using a 6-scale grading system.Inter-rater reliability using Cohen's kappa coefficient(κ) were assessed.Contrast-tonoise ratios(CNR),and signal-to-noise ratios(SNR) for the ZI were calculated for all sequences.Differences in delineation,SNR,and CNR between the sequences were statistically assessed using a paired t-test.For the anatomic validation the coronal FLASH2D-T2Star images were co-registered with a stereotactic atlas(Schaltenbrand-Wahren).RESULTS:The rostral part of the ZI(rZI) could easily be identified and was best and reliably visualized in the coronal FLASH2D-T2Star images.The caudal part was not definable in any of the sequences.No major artifacts in the rZI were observed in any of the scans.FLASH2D-T2Star and SWI imaging offered significant higher CNR values for the rZI compared to T2-TSE images(P > 0.05).The co-registration of the coronal FLASH2D-T2Star images with the stereotactic atlas schema(Schaltenbrand-Wahren) confirmed the correct localization of the ZI in all cases.CONCLUSION:FLASH2D-T2Star imaging(particularly coronal view) provides the reliable and currently optimal visualization of the rZI at 7.0 T.These results can facilitate a better and more precise targeting of the caudal part of the ZI than ever before.展开更多
Following an entropy approach, the electric current can be postulated as a flow of electromagnetic waves that has an electric potential. Such postulate is verified in this article by results of experimental measuremen...Following an entropy approach, the electric current can be postulated as a flow of electromagnetic waves that has an electric potential. Such postulate is verified in this article by results of experimental measurement then it is applied to review Tesla’s discovery of wireless power transmission. Tesla discovered the wireless transmission of electric power during his operation in an entirely new domain of physics based on abrupt discharging of electrostatic charges. He realized that electrons were not responsible for such discovered phenomena. So, he called the new energy as “Radiant Electricity”. He didn’t identify that the true nature of electric current was a flow of electromagnetic waves that can be normally radiated through air. So, he proposed the term “Aether gas” to describe the discovered transfer of the electric charges by radiation from his designed tower, though air, to specified receivers. Following an entropy approach, the nature of the discovered radiated energy can be identified as electromagnetic waves that have an electric potential. So, the followed approach succeeds in eliminating the confusing observations of Tesla’s measurements in his famous experiment and the confusions found in modern literature that deals with such energy as an “Ambiguous Radiant Energy”.展开更多
基金National Natural Science Foundation of China(No.U1831123)。
文摘The quality of the stator winding coil directly affects the performance of the motor.A dual-camera online machine vision detection method to detect whether the coil leads and winding regions were qualified was designed.A vision detection platform was designed to capture individual winding images,and an image processing algorithm was used for image pre-processing,template matching and positioning of the coil lead area to set up a coordinate system.After eliminating image noise by Blob analysis,the improved Canny algorithm was used to detect the location of the coil lead paint stripped region,and the time was reduced by about half compared to the Canny algorithm.The coil winding region was trained with the ShuffleNet V2-YOLOv5s model for the dataset,and the detect file was converted to the Open Neural Network Exchange(ONNX)model for the detection of winding cross features with an average accuracy of 99.0%.The software interface of the detection system was designed to perform qualified discrimination tests on the workpieces,and the detection data were recorded and statistically analyzed.The results showed that the stator winding coil qualified discrimination accuracy reached 96.2%,and the average detection time of a single workpiece was about 300 ms,while YOLOv5s took less than 30 ms.
文摘The characteristic features of operation in a pulsed regime of bifilar Cooper and Tesla coils during magnetic pulse processing and heating of the environment are considered using the dependence of the maximum amplitude at the leading edge of the magnetic pulse <img src="Edit_0a8c724d-3163-470b-b05b-c54ef85a7d58.bmp" alt="" /> on its time duration <em>τ</em>. The spatial distribution of the magnetic induction lines <em><strong>B</strong></em> inside and around the Cooper coil is given, where, unlike the Tesla coil, the maximum values of <em><strong>B</strong></em> arise in the extreme planes of the coil, and its central plane is zero. The defining advantages of new methods of magnetic pulse processing and heating of the environment are considered: the dependence <img src="Edit_8bc48965-e6f8-4005-b1fd-5868944e6862.bmp" alt="" /> at <em>τ</em> → 0;the exchange of energy between the magnetic pulse and the environment;periodic sequence of series of unipolar magnetic pulses at various processing modes. It is shown that 1) for electric fields<em> E<sup>out</sup></em> = 10<sup>10</sup> – 10<sup>12</sup>V/m, arising at the leading edge of a magnetic pulse with duration 10<sup>-5</sup> – 10<sup>-7</sup> s, in the deformation fractal space the electrodynamics of these fields is nonlinear;2) inside the Tesla coil, in the package of conducting tapes and tubes, the pumping energy from the pulsed field <em>E<sup>out</sup></em><sup> </sup>is mainly dissipated in the skin layer in the form of refractory coatings and heats the environment at all stages of plastic deformation of workpieces and heating elements up to the collapse of unstable microcracks. The coefficient of conversion of the pump energy in the pulsed regime with respect to the constant current regime is found.
基金Project supported by the“Strategic Priority Research Program(B)”of the Chinese Academy of Sciences(Grant No.XDB04020200)the Shanghai Municipal Science and Technology Commission Project,China(Grant No.15DZ1940902)
文摘For a practical superconducting quantum interference device（SQUID） based measurement system,the Tesla/volt coefficient must be accurately calibrated.In this paper,we propose a highly efficient method of calibrating a SQUID magnetometer system using three orthogonal Helmholtz coils.The Tesla/volt coefficient is regarded as the magnitude of a vector pointing to the normal direction of the pickup coil.By applying magnetic fields through a three-dimensional Helmholtz coil,the Tesla/volt coefficient can be directly calculated from magnetometer responses to the three orthogonally applied magnetic fields.Calibration with alternating current（AC） field is normally used for better signal-to-noise ratio in noisy urban environments and the results are compared with the direct current（DC） calibration to avoid possible effects due to eddy current.In our experiment,a calibration relative error of about 6.89 × 10-4is obtained,and the error is mainly caused by the non-orthogonality of three axes of the Helmholtz coils.The method does not need precise alignment of the magnetometer inside the Helmholtz coil.It can be used for the multichannel magnetometer system calibration effectively and accurately.
文摘AIM:To evaluate different promising magnetic resonance imaging(MRI) methods at 7.0 Tesla(T) for the pre-stereotactic visualization of the zona incerta(ZI).METHODS:Two neuroradiologists qualitatively and quantitatively examined T2-turbo spin-echo(T2-TSE),T1-weighted gradient-echo,as well as FLASH2D-T2Star and susceptibility-weighted imaging(SWI) for the visualization of the ZI at 7.0 T MRI.Delineation and image quality for the ZI were independently examined using a 6-scale grading system.Inter-rater reliability using Cohen's kappa coefficient(κ) were assessed.Contrast-tonoise ratios(CNR),and signal-to-noise ratios(SNR) for the ZI were calculated for all sequences.Differences in delineation,SNR,and CNR between the sequences were statistically assessed using a paired t-test.For the anatomic validation the coronal FLASH2D-T2Star images were co-registered with a stereotactic atlas(Schaltenbrand-Wahren).RESULTS:The rostral part of the ZI(rZI) could easily be identified and was best and reliably visualized in the coronal FLASH2D-T2Star images.The caudal part was not definable in any of the sequences.No major artifacts in the rZI were observed in any of the scans.FLASH2D-T2Star and SWI imaging offered significant higher CNR values for the rZI compared to T2-TSE images(P > 0.05).The co-registration of the coronal FLASH2D-T2Star images with the stereotactic atlas schema(Schaltenbrand-Wahren) confirmed the correct localization of the ZI in all cases.CONCLUSION:FLASH2D-T2Star imaging(particularly coronal view) provides the reliable and currently optimal visualization of the rZI at 7.0 T.These results can facilitate a better and more precise targeting of the caudal part of the ZI than ever before.
文摘Following an entropy approach, the electric current can be postulated as a flow of electromagnetic waves that has an electric potential. Such postulate is verified in this article by results of experimental measurement then it is applied to review Tesla’s discovery of wireless power transmission. Tesla discovered the wireless transmission of electric power during his operation in an entirely new domain of physics based on abrupt discharging of electrostatic charges. He realized that electrons were not responsible for such discovered phenomena. So, he called the new energy as “Radiant Electricity”. He didn’t identify that the true nature of electric current was a flow of electromagnetic waves that can be normally radiated through air. So, he proposed the term “Aether gas” to describe the discovered transfer of the electric charges by radiation from his designed tower, though air, to specified receivers. Following an entropy approach, the nature of the discovered radiated energy can be identified as electromagnetic waves that have an electric potential. So, the followed approach succeeds in eliminating the confusing observations of Tesla’s measurements in his famous experiment and the confusions found in modern literature that deals with such energy as an “Ambiguous Radiant Energy”.
