108 results about "Magnetic resonance spectrometers" patented technology

A method and system are provided for providing values for control signals for a pulsed magnetic resonance spectrometer such as an NMR spectrometer or an MRI apparatus. The AC output(s) corresponding to a particular signal (e.g. a magnetization or gradient pulse or pulse sequence) originating from a source spectrometer is measured and stored by an independent control unit. The digital output of the independent control unit is then connected to the digital input of the control electronics of a target pulsed magnetic resonance spectrometer, the value of the digital output varied until the AC output(s) of the appropriate signal source of the target spectrometer matches that of the corresponding output(s) of the source spectrometer, corrected, if necessary, for differences in magnetic field strengths.

The invention concerns a superconducting high-field magnet system (1) for a high-resolution magnetic resonance spectrometer, comprising a magnet coil (4) which is superconductingly short-circuited during operation, and generates a homogeneous temporally stable magnetic field during operation that meets the requirements for taking a high-resolution magnetic resonance spectrum. The magnet coil (4) comprises an LTS partial coil (4b, 4c) and an HTS partial coil (4a, 4d). The LTS partial coil (4b, 4c) can be separately short-circuited in a pure LTS circuit (14b) via an LTS switch (15b), and the HTS partial coil (4a, 4d) can be separately short-circuited in a pure HTS circuit (14) via an HTS switch (15a) and both partial coils (4a, 4d; 4b, 4c) are connected via an LTS-HTS joint (20) and are charged by the same power supply.

The present invention provides a pressure cell for pressurizing materials for use in NMR spectroscopy, comprising a sample tube made of sapphire for placing the material, the tube being closed at one end, a housing for holding the sample tube such that the material in the tube can be pressurized, a cove for closing the housing, the cover having an inlet for pressuring the material, means for sealing the cover to the housing, and means of sealing the housing to the sample tube.

The invention provides a method for obtaining a high-resolution three-dimensional NMR spectrum under a non-uniform magnetic field, and relates to nuclear magnetic resonance spectrometers. The method comprises the steps that (1) a one-dimensional spectrum is sampled by using a conventional one-dimensional pulse sequence and used for analyzing the condition of the non-uniformity of the magnetic field to obtain the line width of a spectral line and provide a basis for experimental spectral width parameter settings; (2) a precompiled intermolecular zero-quantum-coherence three-dimensional spectrum pulse sequence is guided into a nuclear magnetic resonance spectrometer; (3) an intermolecular zero-quantum-coherence signal selection module, an indirect dimension evolution period t1 module, an indirect dimension evolution period t2 module, an indirect dimension evolution period t3 module and a signal sampling period t4 module of the intermolecular zero-quantum-coherence three-dimensional spectrum pulse sequence are opened, and experiment parameters of all the modules of the pulse sequence are set; (4) the intermolecular zero-quantum-coherence three-dimensional spectrum pulse sequence in the step (3) after experimental parameter setting is executed, and data sampling is performed; (5) after data sampling is completed, relevant data post-processing is performed, so that the high-resolution three-dimensional NMR spectrum free of influence by the non-uniform magnetic field is obtained.

Layers or coats of materials with high dielectric constant or permittivity with very low conductivity are inserted in between radiofrequency (RF) coil or coil's conductive elements and the sample to enhance the signal to noise ratio (SNR), improve image contrast, and reduce the specific absorption rate (SAR) of magnetic resonance imaging or magnetic resonance spectroscopy instruments. The embodiments of the present invention can be used as an auxiliary device to the standard pre-constructed RF coils or incorporated with RF coil constructions for enhancing RF coil performances in both transmission and reception.

The invention relates to a method for obtaining a nuclear magnetic resonance two-dimensional phase-sensitive J spectrum. The method comprises the following steps: putting a to-be-tested sample into a nuclear magnetic tube and conveying the nuclear magnetic tube loaded with the to-be-tested sample into a detection chamber of a magnetic resonance spectrometer; invoking a conventional one-dimensional hydrogen spectrum pulse sequence to acquire a one-dimensional hydrogen spectrum, obtaining signal peak distribution and spectrum width information, and measuring the non-selective 90-degree radio frequency pulse width; inputting a compiled two-dimensional phase-sensitive J spectrum pulse sequence into the nuclear magnetic resonance spectrometer, opening a chiro pulse weak selection layer gradient combination module and a two-dimensional phase-sensitive J spectrum pulse sequence sampling module of the two-dimensional phase-sensitive J spectrum pulse sequence; setting two-dimensional phase-sensitive J spectrum pulse sequence experiment parameters, inspecting that the experiment parameters are set correctly, and then executing data sampling; after the completion of data sampling, performing corresponding data splicing and two-dimensional Fourier transform to obtain a two-dimensional frequency spectrum containing J coupling information and chemical displacement information; performing two-dimensional phase-sensitive treatment on the obtained two-dimensional frequency spectrum to obtain the two-dimensional phase-sensitive J spectrum.

The invention discloses a two-dimensional diffusion-ordered nuclear magnetic resonance spectroscopy method used for any magnetic field environments and relates to nuclear magnetic resonance spectroscopy detection methods. The method includes the steps of 1), measuring pi / 2 nonselective radiofrequency pulse width and (pi / 2) solvent selective radiofrequency pulse width required by sample stimulation; 2), importing a nuclear magnetic resonance pulse sequence on a nuclear magnetic resonance spectrometer; 3), turning on an intermolecular zero-quantum coherence signal selection module, a time-invariant evolution module and a diffusion order module of the nuclear magnetic resonance pulse sequence and setting experiment parameters of all modules; 4), executing data sampling; 5), performing data post-processing to obtain high-resolution two-dimensional diffusion-ordered spectroscopy. The two-dimensional diffusion-ordered nuclear magnetic resonance spectroscopy method used for any magnetic field environments does not need any shimming operation, a sample preprocessing process and any special hardware devices, is simple, convenient and feasible and is applicable to any conventional nuclear magnetic resonance spectrometers.

A nuclear magnetic resonance transverse relaxation measurement method without J-coupling-effect interference is suitable for a routine liquid magnetic resonance spectrometer. The nuclear magnetic resonance transverse relaxation measurement method without J-coupling-effect interference can eliminate the J-coupling-effect interference. The method comprises the steps of (1), measuring a pi / 2 nonselective RF pulse width required for exciting a sample; (2), introducing a nuclear magnetic resonance pulse sequence into the magnetic resonance spectrometer; (3), starting a transverse relaxation evolution module and a pure chemical shift decoupling module based on a perfect echo for the nuclear magnetic resonance pulse sequence, and setting experiment parameters of the transverse relaxation evolution module and the pure chemical shift decoupling module; (4), performing three-dimensional data sampling; and (5), after data sampling, performing related data after-processing operation, and obtaining a two-dimensional spectrum of which the direct dimension is the pure chemical shift information and the indirect dimension is the transverse relaxation time and error, namely a pure chemical shift-transverse relaxation time two-dimensional correlation spectrum.

EPR spectrometer comprising a ferroelectric single crystal resonator, a rectangular channel with holes in its narrow sides for inserting a sample and wires, a permanent magnet with planar poles, and a coil within the channel connected through the holes by the wires with a modulation source and a NMR spectrometer comprising a magnet, a probe with means for transmitting a radio frequency magnetic pulse and detecting NMR signal, and a ferroelectric single crystal resonator. A ferroelectric single crystal consisting essentially of potassium tantalate and the alkali metal substituting from about 1% to 3% of potassium or a group (V) metal substituting in part for tantalum, having cubic form of perovskite crystalline structure, and essentially free of impurities and defects is also disclosed.

The invention discloses a self-shielding gradient coil of a nuclear magnetic resonance spectrometer and a design method thereof. The invention is characterized in that, the self-shielding gradient coil comprises a main coil and a shielding coil which is coaxially arranged on the outer side of the main coil. The windings of the main coil are composed of a plurality of stages of main coil upper windings and main coil lower windings which are symmetrically arranged up and down. The centers of winding wire troughs, the circle radiuses of winding coils and turns per coil, corresponding to the maincoil upper windings and the main coil lower windings, are symmetrically arranged up and down in the one-to-one mode. The windings of the main coil are wound in the winding wire troughs and are arranged in a single-layer winding mode in the axial direction. Each stage of main coil winding corresponds to an independent driving current channel. According to the self-shielding gradient coil and the design method thereof, the series single-channel circuit design is changed into the matrix multi-channel circuit design, and the coil structure is simplified. The optimization difficulty of a target field is reduced. The probability that the actually generated gradient field is deformed and the linearity is not pure due to the winding translation and the interlayer dislocation is reduced.

The invention provides a magnetic resonance spectrometer, the spectrometer comprises: a scan and reconstruction computer and a control scanning element, wherein the control scanning element comprises a scan resonance engine, a digital excitation engine, a scan sequential control module and a digital signal processing module; the scan resonance engine is connected with the scan and reconstruction computer to generate a scan sequential control subevent, a digital excitation subevent and a digital signal processing subevent, the subevents are respectively sent to the digital excitation engine, the digital signal processing module and the scan sequential control module; the digital excitation engine is connected with a gradient amplifier and a radio-frequency amplifier to generate a gradient waveform signal and a radio-frequency waveform signal; the digital signal processing module is separately connected with a digital radio-frequency receiving unit and the scan and reconstruction computer to receive a magnetic resonance imaging signal and transmit the signal to the scan and reconstruction computer for image reconstruction. The magnetic resonance spectrometer provided by the invention improves the magnetic resonance image quality.

The invention relates to detection of illegal cooking oil, in particular to a method for judging illegal cooking oil by relative contents of characteristic compounds. The method includes: filling an oil sample into a to-be-detected nuclear magnetism tube of a liquid nuclear magnetic resonance spectrometer, and adding a deuterated reagent needed by field locking; directly performing conventional hydrogen spectrum detection; judging indexes of aldehyde>1.2, aromatic hydrocarbon>1.0, conjugated alkene>0.20, oxide>1.0 and free acid>5.5%; and calculating the relative contents of the aldehyde, the aromatic hydrocarbon, the conjugated alkene and the oxide and the mole percent of the free acid accounting for total fatty acids, and if the relative contents exceed limit values, judging the oil sample as the illegal cooking oil. The method is quick and simple. Results can be obtained only 5 min after a sample is taken. The sample is undamaged, and pretreatment is not needed. Data collection can be completed on any high-field nuclear magnetic resonance spectrometers. The results are exported by data analysis. Repeatability and stability of the whole data collection and analysis are good, and large difference due to different used instruments is avoided.

The invention relates to a drainage oil detecting method. Free radicals in an oil product are detected by using an electronic paramagnetic resonance wave spectrometer, and whether the oil product is drainage oil or whether drainage oil is doped in the oil product is judged by comparing the variation trend of the quantity of free radicals before and after temperature change. The method for in-situ test of a sample is wide in applicability, has a good detection effect on various oil products, and can be used for directly detecting whether the drainage oil is doped in the edible oil products.

The invention discloses a magnetic resonance imaging system eddy current compensation method, and belongs to the technical field of magnetic resonance imaging. The method includes the following steps:a, a magnetic resonance spectrometer generates a waveform of a gradient magnetic field according to scanning sequence parameters and outputs the waveform to a gradient amplifier, drives a magnetic resonance scanner to work, and the magnetic resonance spectrometer collects magnetic resonance data; b, gradient trajectory correction is performed according to scanning sequence parameters and eddy current compensation parameters, i.e., the waveform of the gradient magnetic field which changes with time after being influenced by eddy currents is calculated, thereby obtaining a corrected K space trajectory; and c, gridding reconstruction is performed on the magnetic resonance data collected in Step a according to the corrected K space trajectory obtained in Step b or nonuniform Fourier transformation is utilized to reconstruct a magnetic resonance image. The method provided by the invention performs eddy current compensation based on software, avoids hardware input, and improves imaging quality.

The invention relates to a field frequency interlocking system and method of a permanent-magnetic low-field mini NMR spectrometer. The system comprises a magnetic field intensity measurement unit, anadjustable temperature detection control unit and a data processing and display unit; the magnetic field intensity measurement unit is provided with a support, a triaxial orthogonal positioning slideunit and a magnetic field intensity detector, and the magnetic field intensity detector detects the magnetic field intensity of magnet to-be-detected area; the adjustable temperature detection controlunit is provided with a temperature control box, a multipoint temperature detection sensor and an adjustable temperature control circuit, the temperature control box provides a temperature constant environment for a magnet via a PWM method during calibration, and the instant temperature of the magnet is detected during measurement; and the data processing and display unit is provided with a temperature fitting module, a magnetic field intensity fitting module, a resonance frequency fitting module and a display module, and objective functions of temperature in the magnet cavity, magnetic intensity distribution and relation of the resonance frequency and internal cavity temperature are obtained via fitting algorithms. During measurement, a frequency source of the NMR spectrometer receives resonance frequency data and carries out RF excitation on a sample, and a spectral line is corrected automatically. The system and method can be applied to different permanent-magnetic mini NMR instruments.

The invention discloses a tobacco cellulose content determination method, which is characterized by comprising the following steps: firstly, weighing different mass of cellulose standard sample powder, adding the powder into sample tubes which use silicone tubes as internal standard substance, testing in a carbon 13 cross polarization magic angle spinning nuclear magnetic resonance spectrometer, and thus obtaining wave spectrogram of each cellulose standard sample, processing with FeakFit software to obtain a ratio of quantitative peak area of the standard sample in the same wave spectrogram to the quantitative peak area of the internal standard substance, by taking absolute mass of the cellulose in the standard sample as abscissa and taking the ratio as ordinate for drawing, obtaining a standard work curve; then, repeating the steps above, obtaining the ratio of the quantitative peak area of a to-be-determined sample in a to-be-determined tobacco sample wave spectrogram to the quantitative peak area of the internal standard substance, further obtaining absolute mass of the cellulose in the to-be-determined tobacco sample according to the standard work curve, thereby obtaining the cellulose content in the to-be-determined tobacco sample. The determination method needs no pretreatment, is accurate in quantification, and is applicable to determination of tobacco cellulose content in batches.

A method of acquiring a nuclear magnetic resonance two-dimension J spectrum in a superfast manner through single scanning resisting a unidirectional nonuniform magnetic field environment is provided. By utilization cooperation of a selective excitation module and a reunion sampling module, limits of traditional two-dimension J spectrum methods are broken, a two-dimension J spectrum can be acquired by superfast sampling in the unidirectional nonuniform magnetic field environment, influences of unidirectional magnetic field nonuniformity are effectively eliminated, experiment time is greatly shortened, and the application field of the two-dimension J spectrum is broadened. The method is suitable for conventional nuclear magnetic resonance spectrometers, does not need any special hardware apparatus, does not need any special sample pretreatment process, is simple, convenient and feasible, and provides an important means for rapidly acquiring a two-dimension J spectrum of a complex organic sample.

The invention discloses a method for determining the content of GPC (glycerophosphoryl choline) in three types of novel medicines GPC by utilizing a solid nuclear magnetic resonance internal standard method. The method mainly comprises the following steps: adding internal standard hexamethylbenzene in a test sample, acquiring a 13C NMR spectrogram of a sample by adopting a Bruker Avance III 400MHz, a nuclear magnetic resonance spectrometer and a wideband solid CP / MAS probe, and calculating the content of GPC by the 13C peak area of the methyl group contained in the GPC and hexamethylbenzene. According to the method disclosed by the invention, the structure authentication and quantitative analysis of the GPC are completed synchronously, so that the technical problems of the content determination of three types of novel medicine GPC standard substances are solved; the method has very great significance to the GPC development of three types of novel medicines GPC and interest protection of consumers and the healthy development of the GPC medicine industry of our country, and provides reference for the subsequent research of the nuclear magnetism quantitative analysis of other medicaments.

The system describes a means and a method for stabilizing the magnetic field generated in the measuring volume of a high-resolution magnetic resonance spectrometer having an actively shielded magnet coil (4) which is located in a cryostat (2) and which is superconductingly short-circuited. The system comprises a compensation coil (12) which is decoupled from the magnet coil (4), and is disposed on the shielding coil (4b) of the magnet coil (4).

The system describes a means and a method for stabilizing the magnetic field generated in the measuring volume of a high-resolution magnetic resonance spectrometer having an actively shielded magnet coil (4) which is located in a cryostat (2) and which is superconductingly short-circuited. The system comprises a compensation coil (12) which is decoupled from the magnet coil (4), and is disposed on the shielding coil (4b) of the magnet coil (4).

The invention relates to a user-defined bus and an achievement method thereof. The method includes the steps that the bus comprising a back panel, a main panel, a transmitting panel and a plurality of receiving panels is set, a main control unit, a first programmable logic component, a first single chip microcomputer and a crystal oscillator are arranged in the main panel, a second programmable logic component and a second single chip microcomputer are arranged in the transmitting panel, a third programmable logic component and a third single chip microcomputer are arranged in each receiving plate, high-speed buses are arranged between the first programmable logic component and the second programmable logic component and between the first programmable logic component and the third programmable logic components and are used for transmitting real-time control data, reset signals, handshaking signals, reserved signals, bus clock signals and synchronous clock signals, low-speed buses are arranged between the first single chip microcomputer, and the second single chip microcomputer and between the first single chip microcomputer and the third single chip microcomputers and are used for transmitting initial signals or random detection signals. The user-defined bus can be widely used in magnetic resonance spectrometer systems.

A transport device for transporting an NMR sample to the probe head (16) of an NMR spectrometer by means of a transport system (12) is characterized in that the transport device comprises a shuttle (15) adapted for use with a transport system. The transport system is structured to transport an HR-NMR sample spinner or an NMR MAS rotor (5). The shuttle includes a locking device for the NMR MAS rotor, the locking device being formed such that the NMR MAS rotor is released by unlocking the locking device and can be transferred to and received by the NMR MAS probe head. It is therefore possible to rapidly change from NMR spectroscopy of liquids to NMR spectroscopy of solids, and vice versa, simply by exchanging the probe head, without converting the transport system.

The invention discloses an X-nuclear channel broadband pre-amplifier of a high-field nuclear magnetic resonance spectrometer and relates to the pre-amplifier of the nuclear magnetic resonance spectrometer. The pre-amplifier is provided with a radio frequency switch control circuit, a radio frequency switch circuit, a direct current bias circuit, an amplification front-end protection circuit, a quarter-wavelength line, a low-noise amplifier circuit, an output matching network and a working state detection circuit. The output end of the radio frequency switch control circuit is connected with the input end of the radio frequency switch circuit and the input end of the amplification front-end protection circuit, the other input end of the amplification front-end protection circuit is externally connected with a port of the quarter-wavelength line, the other port of the quarter-wavelength line is externally connected with a probe, the input end of the low-noise amplifier circuit is connected with the output end of the amplification front-end protection circuit, the low-noise amplifier circuit is externally connected with the next-level part via the output matching network, the output end of the radio frequency switch circuit is externally connected with the probe, the working state detection circuit is connected with a switch signal generator, and the output end of the working state detection circuit is connected with the input end of the radio frequency switch control circuit.

The invention relates to a four-spectrometer combined analytical instrument suitable for complex chemical samples. The four-spectrometer combined analytical instrument comprises a gas chromatograph, a mass spectrometer, a nuclear magnetic resonance spectrometer and an infrared spectrometer. A detector of the gas chromatograph comprises a thermal conductivity detector, and the gas chromatograph is provided with a shunt connector. The mass spectrometer is connected with the shunt connector of the gas chromatograph through a first connecting pipe, and the first connecting pipe is communicated with a helium source. The mass spectrometer is provided with a first vent connector. The nuclear magnetic resonance spectrometer is connected with the first vent connector of the mass spectrometer through a second connecting pipe, and a first vacuum pump is arranged on the second connecting pipe. The nuclear magnetic resonance spectrometer is provided with a second vent connector. The infrared spectrometer is connected with the second vent connector of the nuclear magnetic resonance spectrometer through a third connecting pipe, and a second vacuum pump is arranged on the third connecting pipe. In the modes of helium conveying and vacuum conveying, the samples are automatically and sequentially made to pass through the gas chromatograph, the mass spectrometer, the nuclear magnetic resonance spectrometer and the infrared spectrometer, and unpredictable components in the samples can be found.

The invention relates to an automatic sampler of a nuclear magnetic resonance spectrometer. The automatic sampler comprises an engine base and a sample case; the sample case comprises a transmission chain, a synchronous belt, a transmission mechanism, a guide groove and a backplane component; the backplane component comprises a backplane, a semicircle fixed connection pipe, a semicircle mobile connection pipe and a slide block; a connector with a seal ring is arranged on the engine base; a sample inlet pipe placed in the magnet field is fixedly connected under the connector; a direct current motor movably connected with the transmission mechanism, a parallel air claw for catching the fixed connection pipe, a push rod cylinder for pushing the mobile connection pipe, a plunger cylinder connected with a tapered plunger, a barcode scanner, a diffuse reflection sensor for detecting a glass pipe of a loaded sample, a serial port plug I connected with an MCU control board, and a fault alarm are installed on the frame. The automatic sampler of the nuclear magnetic resonance spectrometer has small volume, low cost, convenience in installation, high degree of automation, and is convenient, safe and reliable to control.

The invention discloses a special multichannel radio frequency echo signal down converter for an MR-EPT spectrometer, and belongs to the field of MR-EPT imaging. The down converter comprises a local oscillator signal generation module, a power division module and a frequency-mixing amplitude-modulation phase-modulation unit which are connected in sequence, and a control module for controlling thefrequency of a local oscillator signal output by the local oscillator signal generation module and controlling the frequency-mixing amplitude-modulation phase-modulation unit to adjust the amplitude and phase of an output signal. The frequency mixing amplitude modulation and phase modulation unit comprises a plurality of radio frequency amplitude modulation and phase modulation modules. The radiofrequency amplitude modulation and phase modulation module comprises a radio frequency signal processing module for performing sideband suppression and impedance matching on a radio frequency echo signal, which are connected in sequence; a frequency mixing module used for carrying out frequency mixing on multi-channel local oscillation signals output by the power dividing module and radio frequency signals output by the radio frequency signal processing module, a filtering module, an amplifying module, a phase modulation module controlled by the control module to carry out phase shift, and anamplitude modulation module controlled by the control module to carry out amplitude modulation. The problem that an existing magnetic resonance spectrometer cannot be used for MR-EPT imaging in a 9.4T ultrahigh magnetic field environment is solved.

The invention relates to a detection method of qualitative analysis of case drugs by utilizing a micro-nuclear magnetic resonance spectrometer. The detection method comprises the following steps of: establishing a standard hydrogen spectrum database of a 600MHz nuclear magnetic resonance spectrometer of common drugs; detecting case drugs by utilizing a 80MHz micro-nuclear magnetic resonance spectrometer to obtain a 80MHz experimental hydrogen spectrum; adjusting the chemical shift, the baseline and the characteristic peak of the 80MHz experimental hydrogen spectrum to an appropriate ratio to obtain a 80MHz treatment hydrogen spectrum of the case drugs; and referring to the chemical shift of a standard drug hydrogen spectrum of the 600MHz nuclear magnetic resonance spectrometer to analyze the 80MHz treatment hydrogen spectrum to obtain components of the case drugs and other detection results. The common drugs can be identified in the hydrogen spectrum by the characteristic peaks of a benzene ring and a methyl group, and the experimental results of drug component detection are consistent with those of the conventional method. The method provided by the invention has the advantages of simple operation, low cost, small occupied space and the like, and meanwhile, the matter structure can be analyzed and the novel drugs can be detected according to the hydrogen spectrum.

The application discloses a magnetic resonance spectrometer and an apparatus for controlling a magnetic resonance spectrometer based on FPGA. The apparatus includes a control unit and a conversion receiving unit. The control unit includes a clock source. The apparatus is provided with a waveform generation unit and a signal receiving unit therein which are synchronized through the same clock source. The apparatus includes two working modes: a continuous wave mode and an impulse wave mode. The apparatus can output a microwave signal which is modulated by any wave and has higher synchronism and time resolution compared with prior art apparatuses for controlling an electron paramagnetic resonance spectrometer which adopt a plurality of separate clock sources, which enables a second microwave signal in a pulse form generated by the electron paramagnetic resonance spectrometer that is under the control of the apparatus to have a small minimum resolution time of a pulse width and a pulse relative time delay, i.e. a higher time resolution of the second microwave signal. The apparatus is designed based on FPGA, has a higher integration level, and flexible design and low cost.

The invention provides a magnetic resonance spectrometer and a magnetic resonance imaging system, so as to realize the performance index of radio frequency coil self-detecting of the magnetic resonance imaging system. The magnetic resonance spectrometer comprises a radio frequency transmitter, a radio frequency receiver, a radio frequency transmitting coil and a radio frequency receiving coil. Themagnetic resonance spectrometer is characterized in that the magnetic resonance spectrometer further comprises a first power splitter, a second power splitter, first and second pick-up coils which are arranged on both sides of the radio frequency transmitting coil, and third and fourth pick-up coils which are arranged on both sides of the radio frequency receiving coil; the first power splitter is connected with the radio frequency transmitter and the radio frequency transmitting coil; the second power splitter is connected with the radio frequency transmitter, the third pick-up coil and thefourth pick-up coil; the first pick-up coil and the second pick-up coil are connected with the radio frequency receiver; and the radio frequency receiving coil is connected with the radio frequency receiver.