CN115016014A - Small-size multi-turn receiving coil detection device and method for ground magnetic resonance - Google Patents
Small-size multi-turn receiving coil detection device and method for ground magnetic resonance Download PDFInfo
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Abstract
The invention belongs to the field of ground magnetic resonance detection in geophysical exploration, and particularly relates to a small-size multi-turn receiving coil detection device and method for ground magnetic resonance. The device comprises three transmitting coils, a decoupling coil and a receiving coil which are arranged at equal intervals, wherein the three coils are in a ring shape with the same radius, the receiving coil is positioned between the transmitting coil and the receiving coil, and the receiving coil is a differential receiving coil. Decoupling of the receiving and transmitting coil is achieved, dead time is shortened, early signals are obtained, and detection of short relaxation target bodies is achieved. Is suitable for a small-sized receiving coil.
Description
Technical Field
The invention belongs to the field of ground magnetic resonance detection in geophysical exploration, and particularly relates to a small-size multi-turn receiving coil detection device and method for ground magnetic resonance.
Background
The Surface Nuclear Magnetic Resonance (SNMR) technology is a non-invasive geophysical prospecting method based on the Nuclear Magnetic Resonance principle, and is widely applied in the field of water resource detection. When the method is used for detection, firstly, the transmitter transmits excitation pulses through the transmitting coil, hydrogen protons in underground water are excited to a high-energy level state, then the excitation pulses are removed, the hydrogen protons release Free Induction Decay (FID) signals when returning to a low-energy level, the receiver picks up the FID signals through the same coil, and the hydrogeology condition of a detected region is inverted and released after data processing.
FID signal theoretical expression e (t) is shown below:
wherein E0 is the initial amplitude, T2 is the relaxation time,
for the initial phase, fg is the larmor frequency of the detection site. The signal is an exponentially decaying oscillating signal. The part with amplitude higher than the noise floor of the receiver is a valid signal which can be picked up, the duration of the valid signal depends on the relaxation time T2, and the shorter the relaxation time is, the less the valid signal is. In actual field tests, coupling between the transceiver coils can cause a long detection dead zone, and the loss of an early FID signal is serious, so that the traditional SNMR method can only realize detection of free water with a relaxation time of more than tens of milliseconds, and can not detect bound water with a short relaxation time or other organic pollutants with high hydrogen content.
The double-transmitting single-receiving coil structure is based on the mutual offset principle of symmetrical transmitting magnetic fields, is an effective decoupling method, and has been applied to the field of electromagnetism [ Sheishu, Longxia, Zhoushen, etc. ] shallow transient electromagnetic method based on the equivalent back-magnetic flux principle [ J ]. geophysical science and newspaper, 2016,59(9):8 ]. However, due to the difference of the detection principle, the existing electromagnetic coil structure cannot be applied to the field of the ground magnetic resonance. At present, two problems exist in the application of a ground magnetic resonance decoupling structure:
1. in order to ensure the decoupling effect, the decoupling structure usually has higher requirements on the precision of the coil structure, so that a meter-level or hectometer-level large coil scheme of the traditional ground magnetic resonance cannot be adopted, and a small-size transmitting coil and a small-size receiving coil are required.
2. In order to ensure an effective receiving area, a small receiving coil structure with hundreds of turns is needed, however, as the number of turns increases, the equivalent parameters of the coil become larger, especially the parasitic capacitance. This reduces the bandwidth of the coil sensor and seriously affects the quality of the early signal, and the early FID signal is seriously distorted and cannot acquire the true original signal. Especially for signals with short relaxation times, the problem is more severe and even leads to detection failures, but there is currently no method to deal with this problem.
Disclosure of Invention
The present invention is directed to overcome the above-mentioned shortcomings in the prior art, and provides a small-sized multiturn receive coil detection apparatus for terrestrial magnetic resonance on the one hand, and a small-sized multiturn receive coil detection method for terrestrial magnetic resonance on the other hand.
The invention is realized by the following steps:
a small-size multi-turn receiving coil detection device for ground magnetic resonance comprises three transmitting coils, a decoupling coil and a receiving coil, wherein the transmitting coils, the decoupling coil and the receiving coil are arranged at equal intervals, the three coils are annular with the same radius, the receiving coil is located between the transmitting coil and the receiving coil, and the receiving coil is a differential receiving coil.
Furthermore, the three coils are wound on the non-metal framework, and the transmitter is electrically connected with the transmitting coil and the decoupling coil; the receiver is electrically connected to the differential receive coil.
Further, the transmitter is used for generating a transmitting current through the transmitting coil and generating a decoupling current through the decoupling coil; the emission current and the decoupling current are equal in magnitude and opposite in direction;
and the receiver picks up an FID signal released by the target body to be detected through a differential receiving coil.
Furthermore, the receiver comprises a four-way switch, a preamplifier, a band-pass filter, a secondary amplifier and a collection and storage unit;
the four-way change-over switch is composed of four groups of back-to-back MOSFET switches, is connected with a tap of the differential receiving coil and is used for quickly switching between receiving and transmitting states, and the MOSFET switches can be equivalent to resistors in a conducting stage and can be equivalent to capacitors in a turn-off state;
signals received by the four-way selector switch sequentially pass through the preamplifier, the band-pass filter and the secondary amplifier, and are used for performing analog-to-digital conversion and data storage on the FID signals after being conditioned by the acquisition and storage unit.
Further, the four sets of back-to-back MOSFET switches comprise: a first MOSFET switch S1, a second MOSFET switch S2, a third MOSFET switch S3, and a fourth MOSFET switch S4, the first MOSFET switch S1 and the second MOSFET switch S2 being connected in series between one end tap and a center tap of the differential receive coil, the third MOSFET switch S3 and the fourth MOSFET switch S4 being connected in series between the other end tap and the center tap of the differential receive coil; the first MOSFET switch S1 and the second MOSFET switch S2 are connected to one input terminal of the preamplifier, the third MOSFET switch S3 and the fourth MOSFET switch S4 are connected to the other input terminal of the preamplifier, and the center tap is connected to the ground terminal of the preamplifier 7 and then commonly grounded.
Further, the radius of the three coils is between 0.5 and 1 meter.
An early signal acquisition method, which adopts a detection device, comprises the following steps:
a. according to the characteristics of the target to be detected, detecting parameters including the excitation pulse moment, the coil radius and the number of turns of a receiving coil, a decoupling coil and a transmitting coil are determined through forward calculation;
measuring parameters of a receiving coil, wherein the parameters comprise an equivalent inductance L, an equivalent resistance R and an equivalent capacitance C, and calculating a matching resistance Rp according to the following formula:
b. the system works in a transmitting state, the transmitter transmits excitation pulses, at the moment, the four-way change-over switch is connected with two groups of the differential receiving coils and is disconnected, and the two groups of the grounding switches are closed;
c. receiving and transmitting switching, namely removing excitation pulses and switching the states of the four-way selector switch;
d. the system works in a receiving state, the receiver collects and stores signals, the four-way change-over switch is connected with two groups of the differential receiving coils to be closed, and the two groups of the grounding coils to be disconnected;
e. judging whether the detection is finished or not, and when the whole superposition test of all the pulse moments is finished, considering that the detection is finished;
if the step (f) is finished, continuing the step (f), and if the step (b) is not finished, performing the step (b);
f. modeling and solving a transfer function of a system formed by a receiving coil and four paths of change-over switches according to an equivalent circuit, and modeling and solving only half of the differential circuit due to the symmetry of the differential circuit, wherein the receiving coil is equivalent to a mode of connecting a resistor R, an inductor L and a capacitor C in series, a matching resistor Rp is connected with the matching resistor Rp in parallel, a conducting switch is equivalent to a resistor Ron, a switching-off switch is equivalent to a capacitor Coff, the system formed by the coil, the matching resistor and a switch inputs an FID actual measurement signal V (t) equivalent to a signal source and outputs an input signal U (t) of a preamplifier, and the transfer function H(s) is as follows:
the unit impulse response of the system is H n (t), substituting the parameters obtained in step a and equivalent parameters of the MOSFET switch into H(s) to obtain the transfer function.
Further, the method comprises the following steps: correcting the acquired signals, wherein the correction method comprises the following steps:
when n is equal to 1, the reaction solution is,
when n is more than or equal to 2,
……
wherein n is the signal length, the real signal is V (n), and the signal obtained by actual acquisition and processing is U (n).
Compared with the prior art, the invention has the beneficial effects that:
(1) the ground magnetic resonance small-size multi-turn coil provided by the invention can realize a precise structure which is difficult to finish by a traditional ground magnetic resonance large-size coil, realize decoupling of a receiving and transmitting coil, shorten dead time, acquire an early signal and realize detection of a short relaxation target body.
(2) The differential coil structure provided by the invention is matched with a differential preamplifier for use, and compared with the traditional single-ended transmitting coil, the differential coil structure can better inhibit common-mode noise interference, improve the signal-to-noise ratio of detection and improve the detection effect on a short relaxation target body.
(3) According to the early signal acquisition method provided by the invention, based on the coil sensor model, by correcting the detected signal, the FID signal distortion caused by the multi-turn small coil sensor can be compensated, the accuracy of subsequent signal extraction is improved, and the detection effect on the short relaxation target body is optimized.
Additional aspects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.
Drawings
FIG. 1 shows a schematic diagram of a small-sized multi-turn receiving coil detecting device for ground magnetic resonance detection;
fig. 2 shows a schematic structural diagram of a receiving coil and a receiver for ground magnetic resonance detection;
FIG. 3 shows a schematic diagram of an equivalent circuit of a small-sized multi-turn receiving coil for ground magnetic resonance detection;
FIG. 4 is a schematic diagram of an early signal acquisition method of a small-sized multi-turn receiving coil detection device based on ground magnetic resonance detection;
FIG. 5 shows an embodiment of a short relaxation FID theoretical signal, a distorted FID signal after passing through a coil, and a simulated waveform of the FID signal recovered by the method proposed by the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and do not limit the invention.
As shown in fig. 1, a small-sized multi-turn receiving coil detecting device for ground magnetic resonance comprises a transmitter 1, a transmitting coil 2, a decoupling coil 3, a receiving coil 4 and a receiver 5. The transmitting coil 2 and the decoupling coil 3 are distributed on the upper side and the lower side of the receiving coil 4 at equal intervals, and the three coils are wound on the nonmetal framework; the transmitter 1 is electrically connected with the transmitting coil 2 and the decoupling coil 3; the receiver 5 is electrically connected to the receiving coil 4.
The transmitting coil 2 and the decoupling coil 3 are both circular, the radius and the number of turns are the same, the radius is a, the number of turns is N, the receiving coil 4 is a circular differential coil, the radius is a, the total number of turns is 2 × M, and the parameter M, N, a is determined by the property of the target body to be measured, wherein the radius is the same as that of the transmitting coil 2 and the decoupling coil 3;
a transmitter 1 for generating a transmission current by a transmission coil 2 and a decoupling current by a decoupling coil 3; the transmitting current and the decoupling current are equal in magnitude and opposite in direction, so that the magnetic flux induced by the receiving coil is zero in the transmitting stage, and the decoupling function is realized;
the receiver 5 picks up the FID signal released by the target body to be detected through the receiving coil 4;
referring to fig. 2, the receiver 5 includes a four-way switch 6, a preamplifier 7, a band-pass filter 8, a two-stage amplifier 9, and an acquisition and storage unit 10;
and the four-way change-over switch 6 consists of four groups of back-to-back MOSFET switches and is used for quickly switching between the transceiving states. The switch on phase can be equivalent to a resistance Ron and off can be equivalent to a capacitance Coff, and the magnitude of Ron and Coff depends on the selected MOSFET device (see fig. 3(a) and 3 (b)). The four-way switch 6 specifically includes a first MOSFET switch S1, a second MOSFET switch S2, a third MOSFET switch S3 and a fourth MOSFET switch S4, the first MOSFET switch S1 and the second MOSFET switch S2 are connected in series between one end tap and a middle tap of the differential receiving coil, and the third MOSFET switch S3 and the fourth MOSFET switch S4 are connected in series between the other end tap and the middle tap of the differential receiving coil; the first MOSFET switch S1 and the second MOSFET switch S2 are connected to one input terminal of the preamplifier 7, the third MOSFET switch S3 and the fourth MOSFET switch S4 are connected to the other input terminal of the preamplifier 7, and the center tap is connected to the ground terminal of the preamplifier 7 and then commonly grounded.
The received signals are processed by FID signals through a preamplifier 7, a band-pass filter 8 and a secondary amplifier 9 in sequence and then output to an acquisition and storage unit 10.
And the acquisition and storage unit 10 is used for analog-to-digital conversion and data storage.
As shown in fig. 4, an early signal acquiring method based on the above device includes the following steps:
Measuring parameters of the receiving coil 4, including an equivalent inductance L, an equivalent resistance R and an equivalent capacitance C, and calculating a matching resistance Rp according to the following formula:
in step 306, the system composed of the receiving coil 4 and the four-way switch 6 is modeled and solved for the transfer function according to the equivalent circuit shown in fig. 3 (b). Due to the symmetry of the differential circuit, only the portion above GND shown in the figure is modeled and solved. The receiving coil is equivalent to a form of series connection of a resistor R, an inductor L and a capacitor C, the matching resistor Rp is connected in parallel with the receiving coil, the first MOSFET switch S1 is equivalent to a resistor Ron, and the third MOSFET switch S3 is equivalent to a capacitor Coff. The input of the system composed of a coil, a matching resistor and a switch is an FID actual measurement signal V (t) equivalent to a signal source, the output is an input signal U (t) of a preamplifier 7, and a transfer function H(s) is as follows:
the unit impulse response of the system is H n (t) of (d). The transfer function is obtained by substituting the parameters obtained in step 301 and the equivalent parameters of the MOSFET into H(s).
However, the bandwidth of the receiving coil is limited due to the multiple turns of the small loop, and early signal distortion of the FID signal is caused, that is, the real signal is v (t), and the signal obtained by actual acquisition and processing is u (t), so that it is difficult to obtain real key parameters. In order to recover the real signal, the invention provides a corresponding correction method:
when n is equal to 1, the reaction is carried out,
when n is more than or equal to 2,
……
where n is the signal length. According to the above method, the original signal V (t) can be recovered.
Examples
According to the actual detection requirement, the coil radius a is determined to be 0.8M, the number of turns N of the transmitting coil and the decoupling coil is determined to be 16, the number of turns 2 of the receiving coil is determined to be 200, the equivalent resistance Ron is 0.44 Ω when the MOSFET switch is turned on, and the equivalent capacitance Coff is determined to be 32pf when the MOSFET switch is turned off. The specific implementation steps are as follows:
a. and measuring parameters of the receiving coil 4 to obtain a differential coil, wherein 100 turns of the differential coil have equivalent inductance of 44.8mH, equivalent resistance of 48 omega and equivalent capacitance of 22.6uF, and the matching resistance Rp is selected to be 600 omega according to the following formula.
b. The system works in a transmitting state, the transmitter 1 transmits an excitation pulse, S1 and S2 of the four-way change-over switch 6 are opened, and S3 and S4 are closed.
c. And (4) switching between receiving and transmitting. The excitation pulse is removed, and the switch state of the four-way selector switch 6 is switched.
d. The system is operating in a receiving state and the receiver 5 collects the signals and stores them. At this time, S1 and S2 of the four-way changeover switch 6 are closed, and S3 and S4 are opened.
e. And judging whether the detection is finished or not. When the whole superposition test of all the pulse moments is finished, the detection is considered to be finished. If the step (f) is finished, continuing the step (f), and if the step (b) is not finished, performing the step (b);
f. the input of the system composed of a coil, a matching resistor and a switch is an FID measured signal V (t) equivalent to a signal source, the output is an input signal U (t) of a preamplifier 7, and a transfer function H(s) is:
the unit impact response of the system is H n (t)。
Signal correction is performed as follows. V (t) is calculated according to the following formula, the signal length is n:
when n is equal to 1, the reaction is carried out,
when n is more than or equal to 2,
……
initial amplitude E of the theoretical signal E (t) 0 50nV, relaxation time T 2 2ms, initial phase
Larmor frequency f g 2330 Hz. The envelopes of the output signal u (t) and the recovered signal v (t) are shown in fig. 5, and it can be seen that, for the part (above 10 nV) that can be identified by the receiving system, the signal difference between u (t) and e (t) is large, and the signal v (t) recovered by the method proposed by the present invention is substantially identical to the theoretical signal e (t).
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.
Claims (8)
1. A small-size multi-turn receiving coil detection device for ground magnetic resonance is characterized by comprising three transmitting coils, a decoupling coil and a receiving coil, wherein the transmitting coils, the decoupling coil and the receiving coil are arranged at equal intervals, the three coils are annular with the same radius, the receiving coil is located between the transmitting coil and the receiving coil, and the receiving coil is a differential receiving coil.
2. The probe apparatus of claim 1, wherein three coils are wound on the non-metallic frame, and the transmitter is electrically connected to the transmitter coil and the decoupling coil; the receiver is electrically connected to the differential receive coil.
3. A probe apparatus according to claim 2, wherein the transmitter is adapted to generate a transmit current via a transmit coil and a decoupling current via a decoupling coil; the emission current and the decoupling current are equal in magnitude and opposite in direction;
and the receiver picks up an FID signal released by the target body to be detected through a differential receiving coil.
4. A detection device according to claim 2 or 3, wherein the receiver comprises a four-way switch, a preamplifier, a band-pass filter, a two-stage amplifier and an acquisition and storage unit;
the four-way change-over switch is composed of four groups of back-to-back MOSFET switches, is connected with a tap of the differential receiving coil and is used for quickly switching between receiving and transmitting states, and the MOSFET switches can be equivalent to resistors in a conducting stage and can be equivalent to capacitors in a turn-off state;
signals received by the four-way selector switch sequentially pass through the preamplifier, the band-pass filter and the secondary amplifier, and are used for performing analog-to-digital conversion and data storage on the FID signals after being conditioned by the acquisition and storage unit.
5. The detection apparatus of claim 4, wherein the four sets of back-to-back MOSFET switches comprise: a first MOSFET switch S1, a second MOSFET switch S2, a third MOSFET switch S3, and a fourth MOSFET switch S4, the first MOSFET switch S1 and the second MOSFET switch S2 being connected in series between one end tap and a center tap of the differential receive coil, the third MOSFET switch S3 and the fourth MOSFET switch S4 being connected in series between the other end tap and the center tap of the differential receive coil; the first MOSFET switch S1 and the second MOSFET switch S2 are connected to one input terminal of the preamplifier, the third MOSFET switch S3 and the fourth MOSFET switch S4 are connected to the other input terminal of the preamplifier, and the center tap is connected to the ground terminal of the preamplifier 7 and then commonly grounded.
6. A probe apparatus according to claim 1 wherein the radius of the three coils is between 0.5 and 1 meter.
7. An early signal acquisition method using the detection device according to any one of claims 1 to 6, comprising the steps of:
a. according to the characteristics of the target to be detected, detecting parameters including the excitation pulse moment, the coil radius and the number of turns of a receiving coil, a decoupling coil and a transmitting coil are determined through forward calculation;
measuring parameters of a receiving coil, wherein the parameters comprise an equivalent inductance L, an equivalent resistance R and an equivalent capacitance C, and calculating a matching resistance Rp according to the following formula:
b. the system works in a transmitting state, the transmitter transmits excitation pulses, at the moment, the four-way change-over switch is connected with two groups of the differential receiving coils and is disconnected, and the two groups of the grounding switches are closed;
c. receiving and transmitting switching, namely removing excitation pulses and switching the state of a four-way selector switch;
d. the system works in a receiving state, the receiver collects and stores signals, the four-way change-over switch is connected with two groups of the differential receiving coils to be closed, and the two groups of the grounding coils to be disconnected;
e. judging whether the detection is finished or not, and when the whole superposition test of all the pulse moments is finished, considering that the detection is finished;
if the step (f) is finished, continuing the step (f), and if the step (b) is not finished, performing the step (b);
f. modeling and solving a transfer function of a system formed by a receiving coil and four paths of change-over switches according to an equivalent circuit, and modeling and solving only half of the differential circuit due to the symmetry of the differential circuit, wherein the receiving coil is equivalent to a mode of connecting a resistor R, an inductor L and a capacitor C in series, a matching resistor Rp is connected with the matching resistor Rp in parallel, a conducting switch is equivalent to a resistor Ron, a switching-off switch is equivalent to a capacitor Coff, the system formed by the coil, the matching resistor and a switch inputs an FID actual measurement signal V (t) equivalent to a signal source and outputs an input signal U (t) of a preamplifier, and the transfer function H(s) is as follows:
the unit impulse response of the system is H n (t), substituting the parameters obtained in step a and equivalent parameters of the MOSFET switch into H(s) to obtain the transfer function.
8. The early signal acquisition method according to claim 7, comprising the steps of: correcting the acquired signals, wherein the correction method comprises the following steps:
when n is equal to 1, the reaction is carried out,
when n is more than or equal to 2,
……
wherein n is the signal length, the real signal is V (n), and the signal obtained by actual acquisition and processing is U (n).
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Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1130413A2 (en) * | 2000-03-01 | 2001-09-05 | Marconi Medical Systems, Inc. | Decoupling magnetic resonance RF receive coils |
| CN103837899A (en) * | 2014-03-14 | 2014-06-04 | 长沙五维地科勘察技术有限责任公司 | Transient electromagnetic measurement device and method |
| CN105240002A (en) * | 2015-09-23 | 2016-01-13 | 中国石油大学(北京) | Multi-antenna excitation based three-dimensional nuclear magnetic resonance logging instrument |
| CN107102280A (en) * | 2017-06-13 | 2017-08-29 | 武汉普瑞通科技有限公司 | A kind of NMR signal receiving coil, device and nuclear magnetic resonance forward probe method |
| CN108008451A (en) * | 2018-01-30 | 2018-05-08 | 安徽惠洲地质安全研究院股份有限公司 | A kind of transient electromagnetic detection device and the method for eliminating inductive interferences |
| CN108776356A (en) * | 2018-06-08 | 2018-11-09 | 湖南五维地质科技有限公司 | The design method of Transient electromagnetic measure device |
| CN110208864A (en) * | 2019-06-06 | 2019-09-06 | 海南电网有限责任公司白沙供电局 | A kind of underground metalliferous detection system and its detection method |
| CN110989009A (en) * | 2019-11-27 | 2020-04-10 | 吉林大学 | High-sensitivity compensation type underground metal unexplosive object detection device and detection method |
| CN111796331A (en) * | 2020-08-24 | 2020-10-20 | 吉林大学 | Ground magnetic resonance detection device and method for shallow groundwater and hydrocarbon substances |
| CN216209949U (en) * | 2021-11-05 | 2022-04-05 | 吉林大学 | Novel small-size transient electromagnetic exploration device based on non-coplanar active compensation |
-
2022
- 2022-04-20 CN CN202210416420.2A patent/CN115016014A/en active Pending
Patent Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1130413A2 (en) * | 2000-03-01 | 2001-09-05 | Marconi Medical Systems, Inc. | Decoupling magnetic resonance RF receive coils |
| CN103837899A (en) * | 2014-03-14 | 2014-06-04 | 长沙五维地科勘察技术有限责任公司 | Transient electromagnetic measurement device and method |
| CN105240002A (en) * | 2015-09-23 | 2016-01-13 | 中国石油大学(北京) | Multi-antenna excitation based three-dimensional nuclear magnetic resonance logging instrument |
| CN107102280A (en) * | 2017-06-13 | 2017-08-29 | 武汉普瑞通科技有限公司 | A kind of NMR signal receiving coil, device and nuclear magnetic resonance forward probe method |
| CN108008451A (en) * | 2018-01-30 | 2018-05-08 | 安徽惠洲地质安全研究院股份有限公司 | A kind of transient electromagnetic detection device and the method for eliminating inductive interferences |
| CN108776356A (en) * | 2018-06-08 | 2018-11-09 | 湖南五维地质科技有限公司 | The design method of Transient electromagnetic measure device |
| CN110208864A (en) * | 2019-06-06 | 2019-09-06 | 海南电网有限责任公司白沙供电局 | A kind of underground metalliferous detection system and its detection method |
| CN110989009A (en) * | 2019-11-27 | 2020-04-10 | 吉林大学 | High-sensitivity compensation type underground metal unexplosive object detection device and detection method |
| CN111796331A (en) * | 2020-08-24 | 2020-10-20 | 吉林大学 | Ground magnetic resonance detection device and method for shallow groundwater and hydrocarbon substances |
| CN216209949U (en) * | 2021-11-05 | 2022-04-05 | 吉林大学 | Novel small-size transient electromagnetic exploration device based on non-coplanar active compensation |
Non-Patent Citations (1)
| Title |
|---|
| 席振铢;龙霞;周胜;黄龙;宋刚;侯海涛;王亮;: "基于等值反磁通原理的浅层瞬变电磁法", 地球物理学报, no. 09, 15 September 2016 (2016-09-15), pages 3428 - 3435 * |
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