阅读说明：本技术 核磁共振探头以及包括其的双核联测的核磁共振装置 (Nuclear magnetic resonance probe and nuclear magnetic resonance device with dual cores for joint measurement ) 是由 李新 倪卫宁 米金泰 李三国 闫立鹏 崔谦 于 2018-08-01 设计创作，主要内容包括：本发明提出了一种核磁共振探头以及包括其的双核联测的核磁共振装置,该探头包括：电磁噪声屏蔽机构,其包括相互连接的套筒和端盖；线圈骨架,其连接在套筒内并沿轴向方向部分延伸出端盖的表面；射频线圈绕组,其缠绕在线圈骨架上并设在电磁噪声屏蔽机构的套筒内；和天线,其连接射频线圈绕组,并将射频线圈绕组的信号连接到端盖上或与端盖连接的电子元器件上。该探头能够更好地抑制或屏蔽外部信号干扰,结构更简单。(The invention provides a nuclear magnetic resonance probe and a dual-core joint measurement nuclear magnetic resonance device comprising the same, wherein the probe comprises: an electromagnetic noise shielding mechanism including a sleeve and an end cap connected to each other; the coil framework is connected in the sleeve and partially extends out of the surface of the end cover along the axial direction; the radio frequency coil winding is wound on the coil framework and arranged in the sleeve of the electromagnetic noise shielding mechanism; and the antenna is connected with the radio frequency coil winding and connects the signal of the radio frequency coil winding to the end cover or an electronic component connected with the end cover. The probe can better inhibit or shield external signal interference, and has a simpler structure.)

1. A nuclear magnetic resonance probe, comprising:

an electromagnetic noise shielding mechanism including a sleeve and an end cap connected to each other;

the coil framework is connected in the sleeve and partially extends out of the surface of the end cover along the axial direction;

the radio frequency coil winding is wound on the coil framework and arranged in the sleeve of the electromagnetic noise shielding mechanism; and

and the antenna is connected with the radio frequency coil winding and connects the signal of the radio frequency coil winding to the end cover or an electronic component connected with the end cover.

2. The probe of claim 1, wherein one end of the bobbin extends from a middle portion of the end cap beyond a surface of the end cap, and wherein a plurality of first through holes are formed in the end cap around the bobbin and a plurality of second through holes are formed in a rim of the end cap.

3. The probe of claim 1 or 2, wherein the end cap and the sleeve are made of good conductor materials capable of shielding external signal interference, and the good conductor materials comprise aluminum alloy and copper.

4. The probe of any one of claims 1 to 3, wherein the sleeve is detachably connected with an end cover, the end cover is provided with external threads, the upper end of the sleeve is provided with internal threads, and the sleeve is in threaded connection with the end cover.

5. The probe of claim 1, wherein the bobbin is a non-conductive cylindrical tube, the middle lower part of the cylindrical tube is provided with an external thread section with an outer diameter slightly smaller than that of other parts, and the radio frequency coil winding is connected to the external thread section of the bobbin in a winding mode.

6. A probe according to claim 5 wherein the externally threaded section of the cylindrical tube is provided with antenna slots through which antennas connecting the ends of the windings of the radio frequency coil are connected to the end cap.

7. A nuclear magnetic resonance device for dual-core joint measurement is characterized by comprising:

a magnetic body mechanism is arranged on the upper surface of the shell,

one end of the nuclear magnetic resonance probe is inserted into the magnet mechanism, and the end cover is fixedly connected with the magnet mechanism; and

the electronic component is connected with a radio frequency coil winding in the nuclear magnetic resonance probe through an antenna and is structured as follows: the double-frequency resonance circuit and the radio frequency coil winding form a double-frequency resonance circuit, and under the action of a magnet mechanism, the adjustable output parameters and the double-core joint measurement of the double-frequency resonance circuit are realized; wherein the nuclear magnetic resonance probe is the probe according to any one of claims 1 to 6.

8. The apparatus of claim 7, wherein the electronic component comprises: the dual-frequency resonant circuit comprises a first high-voltage capacitor and a first variable capacitance diode which are connected in series on a first circuit of the dual-frequency resonant circuit, and a second high-voltage capacitor, a second variable capacitance diode and an inductor which are connected in series on a second circuit, wherein the first circuit and the second circuit are connected in parallel.

9. The apparatus of claim 8, wherein the first and second lines are connected in parallel and then connected in series with a coil winding in the nmr probe.

10. The device of claim 9, further comprising a signal source terminal, wherein the signal source terminal is connected to an impedance transformer, the impedance transformer is connected to the first line and the second line in parallel, and an output terminal of the first line and the second line after parallel is connected to the rf coil winding.

11. The device according to any one of claims 7 to 10, wherein the nmr probe comprises a sleeve and an end cap, a radio frequency coil winding in the nmr probe is mounted in the sleeve, the end cap is provided with a plurality of first through holes, and the electronic component is mounted on the first through holes in an insulating manner and connected with the radio frequency coil winding in the sleeve through an antenna.

Technical Field

The invention relates to the technical field of material detection and material analysis, in particular to a nuclear magnetic resonance probe for analyzing physical properties by using a nuclear magnetic resonance technology and a nuclear magnetic resonance device for dual-core joint measurement comprising the nuclear magnetic resonance probe.

Background

The nuclear magnetic resonance analyzer detects the signals of characteristic atomic nuclei in the material by utilizing the nuclear magnetic resonance principle, can obtain the content, relaxation and diffusion characteristics of the specific atomic nuclei, the nuclear magnetic spectrum of the measured substance or the image of the measured substance, and directly or indirectly converts the nuclear magnetic resonance signals into key information of the substance, and the information has important significance for material evaluation. The nuclear magnetic resonance instrument is more and more emphasized in the fields of medical treatment, geography, chemistry, materials, food and the like by virtue of the advantages of rapidness, accuracy, no damage and greenness.

The nuclear magnetic resonance analyzer mainly comprises a sensor and an electronic system. The sensor is responsible for providing the place and condition for generating the nuclear magnetic resonance phenomenon, exciting and receiving the nuclear magnetic resonance signal. The device mainly comprises a magnet and an antenna probe, wherein the magnet is used for generating a static magnetic field to enable the hydrogen nuclei in the sample to generate polarization energy level splitting. The antenna probe is used for transmitting radio frequency pulses, exciting hydrogen atoms polarized by a static magnetic field to generate a nuclear magnetic resonance phenomenon, and meanwhile, receiving and collecting nuclear magnetic resonance signals. The electronic system is responsible for providing electronic control signals, high-power radio frequency pulse sequences, weak signal acquisition, amplification sampling and data processing for exciting the nuclear magnetic resonance phenomenon. The electronic system mainly comprises a radio frequency module, a pulse sequence module, a control processing module and a data processing module.

Disclosure of Invention

In view of some or all of the above technical problems in the prior art, the present invention provides a nuclear magnetic resonance probe and a dual-core simultaneous measurement nuclear magnetic resonance apparatus including the same, wherein the probe can better suppress or shield external signal interference, and has a simpler structure. The nuclear magnetic resonance device is easy to install, has two resonant frequencies, has the characteristic of meeting the dual-core joint measurement without replacing a probe or retuning, and is more convenient to use.

In order to achieve the above object, in one aspect, the present invention provides a nuclear magnetic resonance probe including:

an electromagnetic noise shielding mechanism including a sleeve and an end cap connected to each other;

the coil framework is connected in the sleeve and partially extends out of the surface of the end cover along the axial direction;

the radio frequency coil winding is wound on the coil framework and arranged in the sleeve of the electromagnetic noise shielding mechanism; and

and the antenna is connected with the radio frequency coil winding and connects the signal of the radio frequency coil winding to the end cover or an electronic component connected with the end cover.

In the invention, because the electromagnetic noise shielding mechanism is arranged and the radio frequency coil winding is arranged in the sleeve of the electromagnetic noise shielding mechanism, the interference of external signals can be well inhibited or shielded, and the whole structure has less layers and is simpler.

In one embodiment, one end of the coil skeleton extends out of the surface of the end cover from the middle of the end cover, a plurality of first through holes are formed in the end cover around the coil skeleton, and a plurality of second through holes are formed in the edge, close to the end cover, of the end cover. The first through hole is mainly used for mounting electronic components such as a capacitor, an inductor, a control plug or a signal coaxial plug. The second through hole is mainly used for connecting with a magnet mechanism and the like, and has the function of reducing obstruction to a magnetic field signal.

In one embodiment, the end cap and the sleeve are made of good conductor materials capable of shielding external signal interference, and the good conductor materials comprise aluminum alloy and copper. The end cover and the sleeve are made of good conductors such as metal or alloy, so that interference of external signals can be better shielded.

In one embodiment, the sleeve is detachably connected with the end cover, the end cover is provided with an external thread, the upper end of the sleeve is provided with an internal thread, and the sleeve is connected with the end cover through the thread. The installation is convenient. In a preferred embodiment, the diameter of the end cap is greater than the diameter of the sleeve. Mainly because of the connection with the tuning circuit, the resonance can be realized by adopting the radio frequency coil winding with smaller diameter.

In one embodiment, the coil framework is a non-conductive cylindrical tube, an external thread section with an outer diameter slightly smaller than that of other parts is arranged at the middle lower part of the cylindrical tube, and the radio frequency coil winding is connected to the external thread section of the coil framework in a winding mode.

In one embodiment, the external threaded section of the cylindrical tube is provided with antenna slots through which antennas connecting the two ends of the radio frequency coil winding are connected to the end cap. The positions of the radio frequency coil winding and the antenna are convenient to fix.

On the other hand, the invention also provides a nuclear magnetic resonance device for dual-core joint measurement, which comprises:

a magnetic body mechanism is arranged on the upper surface of the shell,

one end of the nuclear magnetic resonance probe is inserted into the magnet mechanism, and the end cover is fixedly connected with the magnet mechanism;

the electronic component is connected with a radio frequency coil winding in the nuclear magnetic resonance probe through an antenna and is structured as follows: the double-frequency resonance circuit and the radio frequency coil winding form a double-frequency resonance circuit, and under the action of a magnet mechanism, the adjustable output parameters and the double-core joint measurement of the double-frequency resonance circuit are realized; the nuclear magnetic resonance probe adopts the probe.

In the present invention, the nuclear magnetic resonance probe is inserted into the magnet mechanism and fixed by a metal fastener such as a screw, so that the mounting is easier. The nuclear magnetic resonance probe is connected with electronic components through the antenna to form a dual-frequency resonance circuit, has two resonance frequencies under the action of the magnet mechanism when being electrified, has the characteristic of meeting dual-core joint measurement without replacing coils and probes or retuning, and is more convenient to use.

In one embodiment, the electronic component includes: the dual-frequency resonant circuit comprises a first high-voltage capacitor and a first variable capacitance diode which are connected in series on a first circuit of the dual-frequency resonant circuit, and a second high-voltage capacitor, a second variable capacitance diode and an inductor which are connected in series on a second circuit, wherein the first circuit and the second circuit are connected in parallel.

In one embodiment, the first line and the second line are connected in parallel and then connected in series with a radio frequency coil winding in the nmr probe.

In one embodiment, the device further includes a signal source end, the signal source end is connected to an impedance transformer, the impedance transformer is connected to a first line and a second line which are connected in parallel, and an output end of the first line and the second line which are connected in parallel is connected to the radio frequency coil winding.

In one embodiment, the nuclear magnetic resonance probe comprises a sleeve and an end cover, a radio frequency coil winding in the nuclear magnetic resonance probe is installed in the sleeve, a plurality of first through holes are formed in the end cover, and an electronic component is installed on the first through holes in an insulation mode and connected with the radio frequency coil winding in the sleeve through an antenna.

Compared with the prior art, the invention has the advantages that:

the nuclear magnetic probe is provided with the electromagnetic noise shielding mechanism, and the radio frequency coil winding is arranged in the sleeve of the electromagnetic noise shielding mechanism, so that the interference of external signals can be well inhibited or shielded, and the whole structure is simpler. By inserting the nmr probe into the magnet mechanism and securing it by metal fasteners such as screws, installation is easier. The nuclear magnetic resonance probe is connected with electronic components through the antenna to form a dual-frequency resonance circuit, has two resonance frequencies under the action of the magnet mechanism when being electrified, has the characteristic of meeting dual-core joint measurement without replacing coils and probes or retuning, and is more convenient to use.

Drawings

Preferred embodiments of the present invention will be described in detail below with reference to the attached drawing figures, wherein:

FIG. 1 is a schematic diagram of a nuclear magnetic resonance probe according to an embodiment of the present invention;

FIG. 2 is a schematic illustration of the nuclear magnetic resonance probe of FIG. 1 in a disassembled configuration;

FIG. 3 is a schematic structural diagram of an embodiment of a dual-core simultaneous measurement NMR apparatus according to the invention;

FIG. 4 is a schematic diagram of the electrical circuit of the dual core nuclear magnetic resonance apparatus shown in FIG. 3;

fig. 5 is a frequency characteristic curve generated by the dual-frequency resonant circuit of fig. 4.

In the drawings, like parts are provided with like reference numerals. The figures are not drawn to scale.

Detailed Description

In order to make the technical solutions and advantages of the present invention more apparent, exemplary embodiments of the present invention are described in further detail below with reference to the accompanying drawings. It is clear that the described embodiments are only a part of the embodiments of the invention, and not an exhaustive list of all embodiments. And the embodiments and features of the embodiments may be combined with each other without conflict.

The inventor notices in the process of invention that the nuclear magnetic resonance probe in the prior art adopts a transmitting coil to transmit in a single frequency, only one sample or one atomic nucleus in the sample can be analyzed in one measurement, and if another atomic nucleus needs to be measured, the probe needs to be replaced. In addition, the probe is easily interfered by external signals, the structure is complex, and a plurality of magnets are not easy to install.

In view of the above disadvantages, embodiments of the present invention provide a nuclear magnetic resonance probe 100 and a nuclear magnetic resonance apparatus 10 for dual core simultaneous measurement of the probe, which will be described in detail below.

Referring to figures 1 and 2, there is shown a schematic structural view of one embodiment of a nuclear magnetic resonance probe 100 of the present invention. In this embodiment, the nmr probe 100 of the invention mainly includes an electromagnetic noise shielding mechanism 101, a coil former 104 (see fig. 2), a radio frequency coil winding 106, and an antenna 401. The electromagnetic noise shielding mechanism 101 mainly includes a sleeve 101A and an end cap 101B connected to each other. The bobbin 104 is attached inside the sleeve 101A and partially extends out of the surface of the end cap 101B in the axial direction. A radio frequency coil winding 106 is wound around the bobbin 104 and disposed within the sleeve 101A of the electromagnetic noise shielding mechanism 101. The antenna 401 is connected to the rf coil winding 106 and couples the signal from the rf coil winding 106 to the endcap 101B or to the electronic component 103 coupled to the endcap 101B. In the present invention, since the electromagnetic noise shielding mechanism 101 is provided and the radio frequency coil winding 106 is disposed in the sleeve 101A of the electromagnetic noise shielding mechanism 101, external signal interference can be suppressed or shielded well, and the overall structure is not so multi-layered, and the structure is simpler.

In one embodiment, as shown in FIG. 1, one end of the bobbin 104 extends out of the surface of the end cap 101B from a through hole 203 in the middle of the end cap 101B. And a plurality of first through holes 204 are provided on the end cap 101B around the bobbin 104. A plurality of second through holes 202 are formed near the edge of the end cap 101B. The first through hole 204 is mainly used for mounting the electronic component 103 such as a capacitor, an inductor, a control plug or a signal coaxial plug. The second through hole 202 is mainly used for connection with the magnet mechanism 105, while having a reduced blocking effect on the magnetic field signal. The electronic component 103 is provided with an insulating sleeve 205 for insulating certain components from the end cap 101B. The through hole 203 in the center of the end cap 101B has a certain height and is provided with an internal thread, and the bobbin 104 is screwed to the through hole 203 by the external thread.

In one embodiment, the end cap 101B and the sleeve 101A are made of a good conductor material that can shield external signal interference. The good conductor material here includes a metal or an alloy, such as an aluminum alloy, copper.

In one embodiment, the sleeve 101A is a circular cylinder with a circular opening in the center of the closed end for mounting the bobbin 104, as shown in fig. 2, and the circular opening is sealed by a plug. The other end of the sleeve 101A is internally threaded. The end cover 101B is integrally in a circular truncated cone shape, one end facing the sleeve 101A is provided with a thread extending portion, the outer diameter of the thread extending portion is slightly smaller than that of a disc portion of the end cover 101B, and the disc portion can play a role in positioning and fixing and can conduct electricity when being connected with the sleeve 101A. In one embodiment, the end cap 101B and the sleeve 101A may be connected by bolts or screws, both of which require conductive contact. After the two are installed together, a better electromagnetic shielding is formed inside, external electromagnetic noise is shielded, and a low-background-noise detection environment is provided for the radio-frequency coil winding 106 arranged inside. In a preferred embodiment, the end cap 101B and the sleeve 101A are detachably connected, and the end cap 101B is provided with an external thread 201. The upper end of the sleeve 101A is provided with internal threads, and the end cover 101B is connected with the sleeve 101A through the threads. This arrangement facilitates installation and sealing of the joint is relatively easy to achieve. More preferably, the diameter of the end cap 101B is larger than the diameter of the 101A sleeve. The main reason is that the probe is connected to a tuned circuit, which can be tuned by using a radio frequency coil winding 106 with a small diameter.

In one embodiment, as shown in fig. 2, the bobbin 104 is a non-conductive cylindrical tube, and the upper end of the cylindrical tube is provided with an external thread connected with the through hole 203 of the end cap 101B, and the external diameter of the thread is slightly smaller than that of the other parts, so that an end face is left to help fixing. The middle lower part of the cylindrical pipe is provided with an external thread section 301 with the outer diameter slightly smaller than that of other parts. The rf coil winding 106 is attached to the outer threaded section 301 of the bobbin 104 by winding.

In one embodiment, the outer threaded section 301 of the cylindrical tube is provided with antenna slots through which antennas 401 connected to the ends of the rf coil winding 106 are connected to the end cap 101B. The antenna slot extends upward to the end cap 101B along the axial direction of the cylindrical tube, so as to fix the positions of the rf coil winding 106 and the antenna 401. The antenna 401 is wound around a sample tube made of teflon, PEEK or other materials not containing the nuclear element to be detected in the form of a solenoid or saddle-shaped antenna. The antenna 401 connects the coil winding 106 with the electronics on the endcap 101B.

The invention also provides a nuclear magnetic resonance device 10 for dual-core joint measurement as shown in fig. 3. In this embodiment, the nuclear magnetic resonance apparatus 10 mainly includes: the magnetic resonance apparatus includes a magnet mechanism 105, a nuclear magnetic resonance probe 100, and an electronic component 103 connected to the nuclear magnetic resonance probe 100 to form a dual-frequency resonance circuit. The magnet mechanism 105 is not limited to be a rectangular parallelepiped or a square structure as shown in fig. 3, and may be a cylindrical structure as needed. The lower end of the nmr probe 100 is inserted into a through hole in the middle of the magnet mechanism 105. The electronic component 103 is connected to the radio frequency coil winding 106 in the nuclear magnetic resonance probe 100 via an antenna 401, and is configured to: and the rf coil winding 106 form a dual frequency resonant circuit. Under the action of the magnet mechanism 105, the output parameter of the dual-frequency resonance circuit can be adjusted and the dual-core simultaneous measurement is realized. The nuclear magnetic resonance probe 100 is a probe having the structure described above.

Referring to fig. 1 and 3, the end cap 101B has a number of second through holes 202 for facilitating mounting and fixing with the magnet 105. Here, the shielding mechanism can be grounded by using a metal fixing mechanism such as a screw or a bolt, thereby further reducing noise. In addition, the magnet mechanism 105 identifies the direction of the magnetic field B0 as being in the transverse direction, and the rf coil winding 106 in the nmr probe 100 is opened upward, so that the direction of the generated excitation rf field B1 is from bottom to top, and the direction perpendicular to the B0 satisfies the resonance excitation condition.

In the present invention, the nuclear magnetic resonance probe 100 is inserted into the magnet mechanism 105 and fixed by a metal fastener such as a screw, so that the mounting is easier. The nuclear magnetic resonance probe 100 is connected with a plurality of electronic components 103 through an antenna 401 to form a double-frequency resonance circuit, has two resonance frequencies under the action of a magnet mechanism 105 when the nuclear magnetic resonance probe is electrified, has the characteristic of meeting double-core joint measurement without replacing coils and probes or retuning, and is more convenient to use.

In addition, with the prominent trend of miniaturization of nuclear magnetic resonance sensors, such nuclear magnetic resonance sensors or nuclear magnetic resonance devices are mainly classified into two types according to the difference of their structures and the positions of sensitive regions: 1) open magnets, which generate sensitive zones outside the magnet array, allow the study of samples of any size, also called single-sided nuclear magnetic resonance, which are not suitable for being placed inside conventional instruments, see in particular the prior patents in the background art. 2) A closed magnet, such as the dual nuclear magnetic resonance device 10 described in the present invention. The enclosed magnet mechanism 105 of the type employed in the present invention creates a sensitive region within the magnet array, allowing a static magnetic field of high field strength and good homogeneity to be established within a particular region using a minimum of magnets. The closed magnet can produce a stronger, more uniform magnetic field than a single-sided magnet, can be equipped with a highly uniform radio frequency field solenoid antenna, and is used to excite and receive nuclear magnetic resonance signals.

In one embodiment, as shown in FIG. 4, a schematic circuit diagram of the NMR apparatus 10 is shown. In fig. 4, the electronic component 103 mainly includes: a first high-voltage capacitor 505A and a first variable capacitance diode 505B provided in series on a first line of the dual-frequency resonance circuit, and a second high-voltage capacitor 504A, a second variable capacitance diode 504B and an inductor 503 provided in series on a second line. The first line is connected in parallel with the second line. In one embodiment, as shown in FIG. 4, the first and second lines are connected in parallel and then connected in series with the RF coil winding 106 in the NMR probe 100.

In one embodiment, the nuclear magnetic resonance device 10 further includes a signal source terminal 501A. The signal source terminal 501A is connected to an impedance transformer 502. The impedance transformer 502 is connected to the first line and the second line connected in parallel, and the output end of the first line and the second line connected in parallel is connected to the rf coil winding 106, thereby forming a loop of the circuit.

In one embodiment, as shown in fig. 2, when the nmr probe 100 mainly includes a sleeve 101A and an end cap 101B, the rf coil winding 106 in the nmr probe is installed in the sleeve, the end cap 101B is provided with a plurality of first through holes 203, and the electronic component 103 is installed on the first through holes 203 in an insulating manner and connected to the rf coil winding 106 in the sleeve 101A through an antenna 401.

Referring to fig. 4, the rf coil winding 106, together with the tuning capacitor and inductor, forms a resonant network via the antenna 401. The resonant network has two resonant frequencies, and the adjustment of the double resonant frequencies and the impedance is flexibly realized by adjusting the numerical values of the capacitor and the inductor.

During transmission, an electromagnetic wave signal with a specific frequency from a radio frequency power amplifier (not shown in fig. 4) enters from a signal source terminal 501A, firstly passes through an impedance transformer 502 with variable impedance, enters a resonant circuit consisting of a first line, a second line and an equivalent inductor of the radio frequency coil winding 106, and generates a radio frequency field B1 for exciting a nuclear magnetic resonance phenomenon of a sample through energy conversion of the resonant circuit, especially through converting electric energy into magnetic energy by the radio frequency coil winding 106. The impedance transformer 502 is mainly used to transform the impedance of the entire resonant circuit to be equal to the impedance of the electronic circuit, thereby achieving the output and input with maximum efficiency.

Upon reception, the nmr signal (magnetic vector variation with resonant frequency) from the sample is first induced to an electromotive force by the rf coil winding 106, amplified by the resonant circuit, then transmitted to a preamplifier (not shown in fig. 4) via the impedance transformer 502 for impedance matching, and then digitally sampled by the acquisition circuit.

In fig. 4, the first high-voltage capacitor 505A and the second high-voltage capacitor 504A are high-voltage capacitors with fixed capacitance values. The second variable capacitance diodes 504B and 505B are varactor diodes, which can be externally connected with signals, and can adjust capacitance values by applying voltages.

Only specific nuclei can excite the nuclear magnetic resonance phenomenon, and a specific resonance frequency exists after the object is placed in the magnetic field generated by the magnet. The coil in the probe emits radio frequency electromagnetic waves with certain energy and the same frequency as the radio frequency electromagnetic waves, nuclear magnetic resonance phenomenon can be excited, nuclear magnetic resonance signals are detected, and the signals are processed to obtain information of the object to be detected. The resonance frequency of the nuclei is determined by the magnetic field strength and the gyromagnetic ratio of the nuclei together. In a particular magnetic field, it is determined by the nucleus itself. In addition, the magnetic resonance frequency ω 0 is γ B0, where ω 0 is a resonance angular frequency, γ is a magnetic rotation ratio, and B0 is a static magnetic field intensity.

For example, the spin ratio γ 1H/2 pi of 1H is 42.58MHz/T, the spin ratio γ 7Li/2 pi of 7Li is 16.546MHz/T, the spin ratio γ 13C/2 pi of 13C is 10.71MHz, and the spin ratio γ 19F/2 pi of 19F is 40.05MHz, that is, under the same static magnetic field condition, different nuclei have different resonance frequencies, and to excite them with the same coil, the nmr probe apparatus is required to have more than one frequency characteristic at the same time.

FIG. 5 shows an example of the frequency response generated by the dual frequency resonance circuit of the nuclear magnetic resonance probe apparatus provided by the present invention, which is seen to have two resonance points at 9.0MHz and 23.2 MHz. The spectrum peak position can be flexibly adjusted by adjusting the values of electronic components in the circuit.

While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, the appended claims are intended to be construed to include preferred embodiments and all such changes and/or modifications as fall within the scope of the invention, and all such changes and/or modifications as are made to the embodiments of the present invention are intended to be covered by the scope of the invention.