A novel algorithm using multiple spherical arrays based on spherical harmonic analysis is proposed to localize wideband acoustic sources. In the novel spherical harmonic algorithm, the re- ceived microphone signals ar...A novel algorithm using multiple spherical arrays based on spherical harmonic analysis is proposed to localize wideband acoustic sources. In the novel spherical harmonic algorithm, the re- ceived microphone signals are firstly used to do the spherical Fourier transformation. Then, the mul- tiple signal classification （MUSIC） algorithm is applied to the spherical components to obtain the an- gular-spectrum. Finally, the angular-spectrum smoothing technique is proposed to obtain the accu- rate localization of wideband sources. In contrast to the traditional single spherical array, the multi- pie spherical arrays used in this paper consist of several randomly distributed spheres in a given plane. The microphones are uniformly placed on each sphere, the same as the usual single spherical array. Simulation comparison of wideband sources localization between a single spherical array and multiple spherical arrays based on the novel algorithm is carried out to validate our proposed meth- od.展开更多
An array of three GdBa_(2)Cu_(3)O_(7‐δ)bulk high‐temperature superconductors(HTS)that mimic the field pole of a high‐power superconducting motor had been magnetized by pulsed field magnetization(PFM)while cooled b...An array of three GdBa_(2)Cu_(3)O_(7‐δ)bulk high‐temperature superconductors(HTS)that mimic the field pole of a high‐power superconducting motor had been magnetized by pulsed field magnetization(PFM)while cooled by liquid nitrogen.The bulk array was magnetized by a passive PFM technique using three vortex‐type coils placed over each individual bulk and connected in series.The trapped magnetic flux density distribution was comparable to the distribution obtained with more traditional quasi‐static magnetization such as field‐cooling.This suggests that the use of PFM technique on arrays of HTS bulks is possible.PFM has also been performed using each coil individually,to magnetize each bulk sequentially.The magnetization sequences showed a maximum reduction of the peak trapped magnetic flux density of 12%due to the demagnetization effect of the magnetization sequence,while the trapped magnetization distribution was improved.展开更多
文摘A novel algorithm using multiple spherical arrays based on spherical harmonic analysis is proposed to localize wideband acoustic sources. In the novel spherical harmonic algorithm, the re- ceived microphone signals are firstly used to do the spherical Fourier transformation. Then, the mul- tiple signal classification （MUSIC） algorithm is applied to the spherical components to obtain the an- gular-spectrum. Finally, the angular-spectrum smoothing technique is proposed to obtain the accu- rate localization of wideband sources. In contrast to the traditional single spherical array, the multi- pie spherical arrays used in this paper consist of several randomly distributed spheres in a given plane. The microphones are uniformly placed on each sphere, the same as the usual single spherical array. Simulation comparison of wideband sources localization between a single spherical array and multiple spherical arrays based on the novel algorithm is carried out to validate our proposed meth- od.
基金supported by JSPS KAKENHI Grant Numbers 20K21044(2020–2022).
文摘An array of three GdBa_(2)Cu_(3)O_(7‐δ)bulk high‐temperature superconductors(HTS)that mimic the field pole of a high‐power superconducting motor had been magnetized by pulsed field magnetization(PFM)while cooled by liquid nitrogen.The bulk array was magnetized by a passive PFM technique using three vortex‐type coils placed over each individual bulk and connected in series.The trapped magnetic flux density distribution was comparable to the distribution obtained with more traditional quasi‐static magnetization such as field‐cooling.This suggests that the use of PFM technique on arrays of HTS bulks is possible.PFM has also been performed using each coil individually,to magnetize each bulk sequentially.The magnetization sequences showed a maximum reduction of the peak trapped magnetic flux density of 12%due to the demagnetization effect of the magnetization sequence,while the trapped magnetization distribution was improved.
