Laser-induced breakdown spectroscopy(LIBS)is a powerful technique for elemental analysis,offering rapid analysis,minimal sample preparation,wide elemental coverage,and portability.To enhance the detection sensitivity ...Laser-induced breakdown spectroscopy(LIBS)is a powerful technique for elemental analysis,offering rapid analysis,minimal sample preparation,wide elemental coverage,and portability.To enhance the detection sensitivity of LIBS,increasing the spectral emission intensity is crucial.This paper explores the use of Tesla coil(TC)discharge as an alternative to spark discharge in silicon LIBS.The study examines the influence of TC discharge on both time-integrated and timeresolved spectra,with and without TC discharge;the corresponding electron temperature and density are obtained.The results show that TC discharge significantly amplifies the spectral intensity,improving signal sensitivity in LIBS analysis.Specifically,in the laser energy range from 7.4 to 24.0 mJ,TC discharge increased the average spectral line intensities of Si(II)385.60 nm and Si(I)390.55 nm by factors of 8.4 and 5.1,respectively.Additionally,the average electron temperature and density were enhanced by approximately 3.2%and 4.2%,respectively,under TC discharge.The advantages of TC discharge include higher energy deposition,extended discharge duration,reduced electrode erosion,and enhanced safety.This research contributes to advancing LIBS technology and expanding its applications in various fields.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
基金the support by the National Key Research and Development Program of China(No.2019YFA0307701)National Natural Science Foundation of China(Nos.11674128,11674124 and 11974138)。
文摘Laser-induced breakdown spectroscopy(LIBS)is a powerful technique for elemental analysis,offering rapid analysis,minimal sample preparation,wide elemental coverage,and portability.To enhance the detection sensitivity of LIBS,increasing the spectral emission intensity is crucial.This paper explores the use of Tesla coil(TC)discharge as an alternative to spark discharge in silicon LIBS.The study examines the influence of TC discharge on both time-integrated and timeresolved spectra,with and without TC discharge;the corresponding electron temperature and density are obtained.The results show that TC discharge significantly amplifies the spectral intensity,improving signal sensitivity in LIBS analysis.Specifically,in the laser energy range from 7.4 to 24.0 mJ,TC discharge increased the average spectral line intensities of Si(II)385.60 nm and Si(I)390.55 nm by factors of 8.4 and 5.1,respectively.Additionally,the average electron temperature and density were enhanced by approximately 3.2%and 4.2%,respectively,under TC discharge.The advantages of TC discharge include higher energy deposition,extended discharge duration,reduced electrode erosion,and enhanced safety.This research contributes to advancing LIBS technology and expanding its applications in various fields.
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.
