We study the quantum fluctuations of the charge and current of two L-C dissipative mesoscopic circuit with the mutual inductance in the vacuum state.Our results show that the system state will evolve to a squeezed coh...We study the quantum fluctuations of the charge and current of two L-C dissipative mesoscopic circuit with the mutual inductance in the vacuum state.Our results show that the system state will evolve to a squeezed coherent state under the effect of external source.We find that the squeezing amplitude parameter is relative to the parameters of circuit and the mutual-inductance coefficient in the existence of dissipation.When the circuit has no dissipation or there is complete coupling between two meshes,the squeezing amplitude parameter only depends on the capacitance's ratio.展开更多
Live line measurement methods can reduce the loss of power outages and eliminate interference. There are three live line measurement methods including integral method, differential method and algebraic method. A simul...Live line measurement methods can reduce the loss of power outages and eliminate interference. There are three live line measurement methods including integral method, differential method and algebraic method. A simulation model of?two coupled parallel transmission lines spanning on the same towers is built in PSCAD and the calculation errors of these three methods are compared with different sampling frequencies by using of Matlab. The effect of harmonic on calculation is also involved. The simulation results indicate that harmonic has the least effect on the algebraic method which provides stable result and small error.展开更多
A live line measurement method for the zero sequence parameters of transmission lines with mutual inductance is introduced. The mathematical models of the measurement method are given. Global Positioning System (GPS) ...A live line measurement method for the zero sequence parameters of transmission lines with mutual inductance is introduced. The mathematical models of the measurement method are given. Global Positioning System (GPS) is used as the synchronous signal for the measurement carried out at different substations simultaneously. The measurement system and digital simulation results are given. Finally, the live line measurement results of two 220 kV transmission lines with mutual inductance in Hainangrid are given. Results from both simulation and on-site measurement show that the live line measurement method is feasible, and its measurement accuracy can satisfactorily meet the requirements of engineering measurement.展开更多
The design process for integrated inductors generally requires a geometry optimization step. During this step, many geometries must be simulated and fast and accurate formulae are therefore required for the computatio...The design process for integrated inductors generally requires a geometry optimization step. During this step, many geometries must be simulated and fast and accurate formulae are therefore required for the computation of self and mutual inductances of turns. This paper especially deals with numerical evaluation of the mutual inductance of two coaxial circular wire loops. Several computation methods are presented and compared. Finally, an expression is built-up and proven to be very few computing time consuming and 1% accurate for any kind of geometry. The application of this expression to integrated inductive components modelization is recalled to mind, however, this work gives a general and fast computable solution to the electromagnetic problem.展开更多
Small multi-turn coil devices are used with the transient electromagnetic method (TEM) in areas with limited space, particularly in underground environments such as coal mines roadways and engineering tunnels, and f...Small multi-turn coil devices are used with the transient electromagnetic method (TEM) in areas with limited space, particularly in underground environments such as coal mines roadways and engineering tunnels, and for detecting shallow geological targets in environmental and engineering fields. However, the equipment involved has strong mutual inductance coupling, which causes a lengthy turn-off time and a deep “blind zone”. This study proposes a new transmitter device with a conical-shape source and derives the radius formula of each coil and the mutual inductance coefficient of the cone. According to primary field characteristics, results of the two fields created, calculation of the conical-shaped source in a uniform medium using theoretical analysis, and a comparison of the inductance of the new device with that of the multi-turn coil, show that inductance of the multi-turn coil is nine times greater than that of the conical source with the same equivalent magnetic moment of 926.1 A·m2. This indicates that the new source leads to a much shallower “blind zone.” Furthermore, increasing the bottom radius and turn of the cone creates a larger mutual inductance but increasing the cone height results in a lower mutual inductance. Using the superposition principle, the primary and secondary magnetic fields for a conical source in a homogeneous medium are calculated; results indicate that the magnetic behavior of the cone is the same as that of the multi-turn coils, but the transient responses of the secondary field and the total field are more stronger than those of the multi-turn coils. To study the transient response characteristics using a cone-shaped source in a layered earth, a numerical filtering algorithm is then developed using the fast Hankel transform and the improved cosine transform, again using the superposition principle. During development, an average apparent resistivity inverted from the induced electromotive force using each coil is defined to represent the comprehensive resistivity of the conical source. To verify the forward calculation method, the transient responses of H type models and KH type models are calculated, and data are inverted using a “smoke ring” inversion. The results of inversion have good agreement with original models and show that the forward calculation method is effective. The results of this study provide an option for solving the problem of a deep “blind zone” and also provide a theoretical indicator for further research.展开更多
An algorithm for precisely calculating the inductance of a three-section solenoid is presented, which is based on summing the layer self-inductances and the mutual inductances. A theoretical model with ex plicit expre...An algorithm for precisely calculating the inductance of a three-section solenoid is presented, which is based on summing the layer self-inductances and the mutual inductances. A theoretical model with ex plicit expressions is firstly developed to calculate the self-inductance of a single layer, and then numerical calcu lation of the mutual inductance between two layers is introduced. Using the presented computation method, the inductance of a solenoid designed in the experiment is successfully calculated (4.30 mH), which has a difference of less than 1% from the experimental data.展开更多
Polygonal coil systems are designed for increasing and more kinds of sensors and electromagnetic systems.This paper presents a method for calculating mutual inductance between polygonal coils including irregular polyg...Polygonal coil systems are designed for increasing and more kinds of sensors and electromagnetic systems.This paper presents a method for calculating mutual inductance between polygonal coils including irregular polygons.Based on the Biot-Savart law,the method calculates mutual inductance by dividing a polygonal coil into finite wires,and expresses the magnetic induction intensity generated by the excitation coil as a function of the spatial position of each vertex of the coil.The calculation method of the feasible region of the objective function is updated and the calculation process is simplified,so the calculation accuracy is improved.For octagon coils arbitrarily positioned in space,the accuracy of the algorithm is verified by the simulation and experiment.展开更多
The inductively coupled coils principally consist of two coils with no physical connection in between.A major problem is a mutual inductance between the two coils,which caused the frequency response peaks splitting.In...The inductively coupled coils principally consist of two coils with no physical connection in between.A major problem is a mutual inductance between the two coils,which caused the frequency response peaks splitting.In this study,it was found that the position of the splitting of the peaks is not only related to the coupling coefficient(k)but also related to the quality factor(Q)of the coil.Based on this research,we construct a coupled coil for use in a 1.5T clinical MR scanner,this coil,comprising two semicircular coils fixed symmetrically around on a cylinde frame,was designed and constructed.The3-inch surface coil supplied by the MR scanner was used to compare imaging performance with the coupled coil.A water phantom was used for the signal-to-noise ratio(SNR)measurements.A total of 52 male Sprague-Dawley rats and 16 male BALB/C nude mice were scanned in this study for feasibility evaluation.展开更多
摘要We study the quantum fluctuations of the charge and current of two L-C dissipative mesoscopic circuit with the mutual inductance in the vacuum state.Our results show that the system state will evolve to a squeezed coherent state under the effect of external source.We find that the squeezing amplitude parameter is relative to the parameters of circuit and the mutual-inductance coefficient in the existence of dissipation.When the circuit has no dissipation or there is complete coupling between two meshes,the squeezing amplitude parameter only depends on the capacitance's ratio.
摘要Live line measurement methods can reduce the loss of power outages and eliminate interference. There are three live line measurement methods including integral method, differential method and algebraic method. A simulation model of?two coupled parallel transmission lines spanning on the same towers is built in PSCAD and the calculation errors of these three methods are compared with different sampling frequencies by using of Matlab. The effect of harmonic on calculation is also involved. The simulation results indicate that harmonic has the least effect on the algebraic method which provides stable result and small error.
摘要A live line measurement method for the zero sequence parameters of transmission lines with mutual inductance is introduced. The mathematical models of the measurement method are given. Global Positioning System (GPS) is used as the synchronous signal for the measurement carried out at different substations simultaneously. The measurement system and digital simulation results are given. Finally, the live line measurement results of two 220 kV transmission lines with mutual inductance in Hainangrid are given. Results from both simulation and on-site measurement show that the live line measurement method is feasible, and its measurement accuracy can satisfactorily meet the requirements of engineering measurement.
摘要The design process for integrated inductors generally requires a geometry optimization step. During this step, many geometries must be simulated and fast and accurate formulae are therefore required for the computation of self and mutual inductances of turns. This paper especially deals with numerical evaluation of the mutual inductance of two coaxial circular wire loops. Several computation methods are presented and compared. Finally, an expression is built-up and proven to be very few computing time consuming and 1% accurate for any kind of geometry. The application of this expression to integrated inductive components modelization is recalled to mind, however, this work gives a general and fast computable solution to the electromagnetic problem.
基金supported by the National Natural Science Foundation of China(Nos.41564001 and 41572185)the Natural Science Foundation of Jiangxi Province(No.20151BAB203045)
摘要Small multi-turn coil devices are used with the transient electromagnetic method (TEM) in areas with limited space, particularly in underground environments such as coal mines roadways and engineering tunnels, and for detecting shallow geological targets in environmental and engineering fields. However, the equipment involved has strong mutual inductance coupling, which causes a lengthy turn-off time and a deep “blind zone”. This study proposes a new transmitter device with a conical-shape source and derives the radius formula of each coil and the mutual inductance coefficient of the cone. According to primary field characteristics, results of the two fields created, calculation of the conical-shaped source in a uniform medium using theoretical analysis, and a comparison of the inductance of the new device with that of the multi-turn coil, show that inductance of the multi-turn coil is nine times greater than that of the conical source with the same equivalent magnetic moment of 926.1 A·m2. This indicates that the new source leads to a much shallower “blind zone.” Furthermore, increasing the bottom radius and turn of the cone creates a larger mutual inductance but increasing the cone height results in a lower mutual inductance. Using the superposition principle, the primary and secondary magnetic fields for a conical source in a homogeneous medium are calculated; results indicate that the magnetic behavior of the cone is the same as that of the multi-turn coils, but the transient responses of the secondary field and the total field are more stronger than those of the multi-turn coils. To study the transient response characteristics using a cone-shaped source in a layered earth, a numerical filtering algorithm is then developed using the fast Hankel transform and the improved cosine transform, again using the superposition principle. During development, an average apparent resistivity inverted from the induced electromotive force using each coil is defined to represent the comprehensive resistivity of the conical source. To verify the forward calculation method, the transient responses of H type models and KH type models are calculated, and data are inverted using a “smoke ring” inversion. The results of inversion have good agreement with original models and show that the forward calculation method is effective. The results of this study provide an option for solving the problem of a deep “blind zone” and also provide a theoretical indicator for further research.
摘要An algorithm for precisely calculating the inductance of a three-section solenoid is presented, which is based on summing the layer self-inductances and the mutual inductances. A theoretical model with ex plicit expressions is firstly developed to calculate the self-inductance of a single layer, and then numerical calcu lation of the mutual inductance between two layers is introduced. Using the presented computation method, the inductance of a solenoid designed in the experiment is successfully calculated (4.30 mH), which has a difference of less than 1% from the experimental data.
摘要Polygonal coil systems are designed for increasing and more kinds of sensors and electromagnetic systems.This paper presents a method for calculating mutual inductance between polygonal coils including irregular polygons.Based on the Biot-Savart law,the method calculates mutual inductance by dividing a polygonal coil into finite wires,and expresses the magnetic induction intensity generated by the excitation coil as a function of the spatial position of each vertex of the coil.The calculation method of the feasible region of the objective function is updated and the calculation process is simplified,so the calculation accuracy is improved.For octagon coils arbitrarily positioned in space,the accuracy of the algorithm is verified by the simulation and experiment.
摘要The inductively coupled coils principally consist of two coils with no physical connection in between.A major problem is a mutual inductance between the two coils,which caused the frequency response peaks splitting.In this study,it was found that the position of the splitting of the peaks is not only related to the coupling coefficient(k)but also related to the quality factor(Q)of the coil.Based on this research,we construct a coupled coil for use in a 1.5T clinical MR scanner,this coil,comprising two semicircular coils fixed symmetrically around on a cylinde frame,was designed and constructed.The3-inch surface coil supplied by the MR scanner was used to compare imaging performance with the coupled coil.A water phantom was used for the signal-to-noise ratio(SNR)measurements.A total of 52 male Sprague-Dawley rats and 16 male BALB/C nude mice were scanned in this study for feasibility evaluation.