The interference of carrier magnetic field to geomagnetic field has been a difficult problem for a long time,which influences on the deviation of navigation compass and the error of geomagnetic measurement. To increas...The interference of carrier magnetic field to geomagnetic field has been a difficult problem for a long time,which influences on the deviation of navigation compass and the error of geomagnetic measurement. To increase the geomagnetic measuring accuracy required for the geomagnetic matching localization,the strategy to eliminate the effect of connatural and induced magnetic fields of carrier on the geomagnetic measuring accuracy is investigated. The magnetic-dipole's magnetic field distributing theory is used to deduce the magnetic composition in the position of the sensor installed on the carrier. A geomagnetic measurement model is established by using the measuring data with the ideal sensor. Considering the magnetic disturbance of carrier and the error of sensor,a geomagnetic measuring compensation model is built. This model can be used to compensate the errors of carrier magnetic field and magnetic sensor in any case and its parameters have clear or specific physical meaning. The experimented results show that the model has higher geomagnetic measuring accuracy than that of others.展开更多
Measurement of integral field is an important method to test design and manufacture for magnets. There are unavoidable errors during the process of magnets batch production.The demountable poles chamfered size, the we...Measurement of integral field is an important method to test design and manufacture for magnets. There are unavoidable errors during the process of magnets batch production.The demountable poles chamfered size, the weight of the magnet and the symmetry and deviation of punching sheets are the main factors to influence on the magnet integral field quality. By measuring,chamfering and shimming the magnet ends, we may make the reproducibility of CSRe dipoles reach to the requirement of CSR project. Fig. 1 is the schematic diagram of measurement system of integral field for CSRe dipoles.展开更多
The field mapping measurement of 16 C-type CSRe dipoles was measured by using Hall Sensor in last year. The main parameters of the dipoles for CSRe are listed in Table 1. The hall sensor mapping system of HIRFL- CSR c...The field mapping measurement of 16 C-type CSRe dipoles was measured by using Hall Sensor in last year. The main parameters of the dipoles for CSRe are listed in Table 1. The hall sensor mapping system of HIRFL- CSR consists of a single hall sensor, mapping bench and data acquirement system. The hall sensor is produced by AREPOC Co. Its absolute measurement errors are below 5×10-5 T after calibrated with NMR.展开更多
Spatiotemporal variations of the nondipole （ND） magnetic field over the Chinese mainland and neighboring regions from 10000 BC to 1990 AD were analyzed using the latest global geomagnetic models CALS10K.1b, CALS3K.4...Spatiotemporal variations of the nondipole （ND） magnetic field over the Chinese mainland and neighboring regions from 10000 BC to 1990 AD were analyzed using the latest global geomagnetic models CALS10K.1b, CALS3K.4, and IGRF 11. Moreover, for field sources, we investigated 2 n （n = 2 -10） pole ND fields and their energies. The results suggest that the study period can be divided into three. The intensity of the ND field has been mainly positive since 10000 BC and lasted almost 7500 years, then gradually decreased to negative in 2500 BC to 1500 AD, and finally sharply increased to positive. The anomaly areas of the ND field in East Asia took shape for n - 3, when the anomaly areas in East Asia were shaped into closed circles in the mainland. This suggests that the first three harmonic degrees account for most of the ND field. The energy of the ND field rapidly attenuates at the core mantle boundary and is stable at the surface.展开更多
On the basis of Wilson's work in which the vertical electric dipole is centrally located in GHz Transverse ElectroMagnetic (GTEM) cell, we deduce the expression for the field distribution excited by an electric di...On the basis of Wilson's work in which the vertical electric dipole is centrally located in GHz Transverse ElectroMagnetic (GTEM) cell, we deduce the expression for the field distribution excited by an electric dipole in the case that the dipole is not centrally located. It will be useful for EMC measurements using GTEM cell.展开更多
The paper analyze the polarization of study dielectric that produced field by dipole, medium field plays an important role in electromagnetic wave radiation. The electric field expression for electric dipole electric ...The paper analyze the polarization of study dielectric that produced field by dipole, medium field plays an important role in electromagnetic wave radiation. The electric field expression for electric dipole electric field distribution in ordinary textbooks only give a special direction, This paper introduces in detail the formula of the electric dipole in the space of an arbitrary point excitation electric field, and use computer sottware to simulate the distribution pattern of electric dipole, and gives some typical figures for reference.展开更多
The technique of integration within an ordered product of operators and the coherent-state representation are used to convert exponential operators of basis operators (P<SUP>2</SUP>, Q<SUP>2</SUP&...The technique of integration within an ordered product of operators and the coherent-state representation are used to convert exponential operators of basis operators (P<SUP>2</SUP>, Q<SUP>2</SUP>, PQ + QP) to those of the basis operators (a<SUP>2</SUP>, a<SUP>?2</SUP>, a<SUP>?</SUP>a). The coherent state representation of unitary squeezing operators in the factorized form and their normal product form are thus derived. The squeezing engendered by operators of the general form is also obtained.展开更多
Marine controlled source electromagnetic signal could be used in mineral resource exploration,reservoir appraisal and communicative technique in ocean. It's necessary to study the electromagnetic generated by MCSE...Marine controlled source electromagnetic signal could be used in mineral resource exploration,reservoir appraisal and communicative technique in ocean. It's necessary to study the electromagnetic generated by MCSEM. The propagation of the electromagnetic fields from a controlled source in the marine environment was studied with virtual interface method combined with discrete complex image method. Transmitter of finite length current source is approximated by dipole (HED) . A three-layered model is accepted,with sea water as intermediate conductive layer under air and a relatively high resistive seabed as basement,possibly containing a hydrogen layer of higher resistivity. The electromagnetic fields in whole space thus computed show that: (1) the spatial distribution of field component depends on its type; (2) inline Ex component is more sensitive to reservoir layer than that in broadside; (3) The airwave affects marine electromagnetic (MEM) exploration when sea water is relatively shallow; in the case of deep water MEM exploration,the airwave influence could be neglected; and (4) an appropriate frequency should be selected in order to balance the signal strength and electromagnetic induction effect.展开更多
基金Sponsored by National Defence the 11th Five-Year Pre-research Project (51309060301)
文摘The interference of carrier magnetic field to geomagnetic field has been a difficult problem for a long time,which influences on the deviation of navigation compass and the error of geomagnetic measurement. To increase the geomagnetic measuring accuracy required for the geomagnetic matching localization,the strategy to eliminate the effect of connatural and induced magnetic fields of carrier on the geomagnetic measuring accuracy is investigated. The magnetic-dipole's magnetic field distributing theory is used to deduce the magnetic composition in the position of the sensor installed on the carrier. A geomagnetic measurement model is established by using the measuring data with the ideal sensor. Considering the magnetic disturbance of carrier and the error of sensor,a geomagnetic measuring compensation model is built. This model can be used to compensate the errors of carrier magnetic field and magnetic sensor in any case and its parameters have clear or specific physical meaning. The experimented results show that the model has higher geomagnetic measuring accuracy than that of others.
文摘Measurement of integral field is an important method to test design and manufacture for magnets. There are unavoidable errors during the process of magnets batch production.The demountable poles chamfered size, the weight of the magnet and the symmetry and deviation of punching sheets are the main factors to influence on the magnet integral field quality. By measuring,chamfering and shimming the magnet ends, we may make the reproducibility of CSRe dipoles reach to the requirement of CSR project. Fig. 1 is the schematic diagram of measurement system of integral field for CSRe dipoles.
文摘The field mapping measurement of 16 C-type CSRe dipoles was measured by using Hall Sensor in last year. The main parameters of the dipoles for CSRe are listed in Table 1. The hall sensor mapping system of HIRFL- CSR consists of a single hall sensor, mapping bench and data acquirement system. The hall sensor is produced by AREPOC Co. Its absolute measurement errors are below 5×10-5 T after calibrated with NMR.
基金supported by the National Natural Science Foundation of China(Grant No.41404053)the Natural Science Foundation of Jiangsu Province,China(Grant No.BK20140994)
文摘Spatiotemporal variations of the nondipole （ND） magnetic field over the Chinese mainland and neighboring regions from 10000 BC to 1990 AD were analyzed using the latest global geomagnetic models CALS10K.1b, CALS3K.4, and IGRF 11. Moreover, for field sources, we investigated 2 n （n = 2 -10） pole ND fields and their energies. The results suggest that the study period can be divided into three. The intensity of the ND field has been mainly positive since 10000 BC and lasted almost 7500 years, then gradually decreased to negative in 2500 BC to 1500 AD, and finally sharply increased to positive. The anomaly areas of the ND field in East Asia took shape for n - 3, when the anomaly areas in East Asia were shaped into closed circles in the mainland. This suggests that the first three harmonic degrees account for most of the ND field. The energy of the ND field rapidly attenuates at the core mantle boundary and is stable at the surface.
基金Supported by the Innovation Project of Chinese Academy of Sciences
文摘On the basis of Wilson's work in which the vertical electric dipole is centrally located in GHz Transverse ElectroMagnetic (GTEM) cell, we deduce the expression for the field distribution excited by an electric dipole in the case that the dipole is not centrally located. It will be useful for EMC measurements using GTEM cell.
文摘The paper analyze the polarization of study dielectric that produced field by dipole, medium field plays an important role in electromagnetic wave radiation. The electric field expression for electric dipole electric field distribution in ordinary textbooks only give a special direction, This paper introduces in detail the formula of the electric dipole in the space of an arbitrary point excitation electric field, and use computer sottware to simulate the distribution pattern of electric dipole, and gives some typical figures for reference.
文摘The technique of integration within an ordered product of operators and the coherent-state representation are used to convert exponential operators of basis operators (P<SUP>2</SUP>, Q<SUP>2</SUP>, PQ + QP) to those of the basis operators (a<SUP>2</SUP>, a<SUP>?2</SUP>, a<SUP>?</SUP>a). The coherent state representation of unitary squeezing operators in the factorized form and their normal product form are thus derived. The squeezing engendered by operators of the general form is also obtained.
基金Supperted by project of the National Science Foundation of China(No.40874050)
文摘Marine controlled source electromagnetic signal could be used in mineral resource exploration,reservoir appraisal and communicative technique in ocean. It's necessary to study the electromagnetic generated by MCSEM. The propagation of the electromagnetic fields from a controlled source in the marine environment was studied with virtual interface method combined with discrete complex image method. Transmitter of finite length current source is approximated by dipole (HED) . A three-layered model is accepted,with sea water as intermediate conductive layer under air and a relatively high resistive seabed as basement,possibly containing a hydrogen layer of higher resistivity. The electromagnetic fields in whole space thus computed show that: (1) the spatial distribution of field component depends on its type; (2) inline Ex component is more sensitive to reservoir layer than that in broadside; (3) The airwave affects marine electromagnetic (MEM) exploration when sea water is relatively shallow; in the case of deep water MEM exploration,the airwave influence could be neglected; and (4) an appropriate frequency should be selected in order to balance the signal strength and electromagnetic induction effect.
