CN117253689A - Nuclear magnetic resonance permanent magnet - Google Patents
Nuclear magnetic resonance permanent magnet Download PDFInfo
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- CN117253689A CN117253689A CN202311095475.9A CN202311095475A CN117253689A CN 117253689 A CN117253689 A CN 117253689A CN 202311095475 A CN202311095475 A CN 202311095475A CN 117253689 A CN117253689 A CN 117253689A
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- 238000005481 NMR spectroscopy Methods 0.000 title claims abstract description 33
- 230000005291 magnetic effect Effects 0.000 claims abstract description 115
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical group [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 19
- 239000000463 material Substances 0.000 claims description 18
- 230000005294 ferromagnetic effect Effects 0.000 claims description 15
- 229910052761 rare earth metal Inorganic materials 0.000 claims description 14
- 150000002910 rare earth metals Chemical class 0.000 claims description 14
- 230000005389 magnetism Effects 0.000 claims description 5
- 239000000696 magnetic material Substances 0.000 claims description 4
- 239000000543 intermediate Substances 0.000 description 26
- 238000010586 diagram Methods 0.000 description 6
- 230000008859 change Effects 0.000 description 5
- 230000006378 damage Effects 0.000 description 4
- 230000009286 beneficial effect Effects 0.000 description 3
- 208000027418 Wounds and injury Diseases 0.000 description 2
- 239000003302 ferromagnetic material Substances 0.000 description 2
- 208000014674 injury Diseases 0.000 description 2
- 229910052742 iron Inorganic materials 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 238000000655 nuclear magnetic resonance spectrum Methods 0.000 description 2
- 238000004904 shortening Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 230000004075 alteration Effects 0.000 description 1
- 235000008429 bread Nutrition 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 235000013305 food Nutrition 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000000329 molecular dynamics simulation Methods 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 238000004445 quantitative analysis Methods 0.000 description 1
Classifications
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F7/00—Magnets
- H01F7/02—Permanent magnets [PM]
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/05—Detecting, measuring or recording for diagnosis by means of electric currents or magnetic fields; Measuring using microwaves or radio waves
- A61B5/055—Detecting, measuring or recording for diagnosis by means of electric currents or magnetic fields; Measuring using microwaves or radio waves involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging
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- Health & Medical Sciences (AREA)
- Physics & Mathematics (AREA)
- Life Sciences & Earth Sciences (AREA)
- Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
- Engineering & Computer Science (AREA)
- Pathology (AREA)
- Heart & Thoracic Surgery (AREA)
- Radiology & Medical Imaging (AREA)
- Power Engineering (AREA)
- Biophysics (AREA)
- Electromagnetism (AREA)
- Biomedical Technology (AREA)
- High Energy & Nuclear Physics (AREA)
- Medical Informatics (AREA)
- Molecular Biology (AREA)
- Surgery (AREA)
- Animal Behavior & Ethology (AREA)
- General Health & Medical Sciences (AREA)
- Public Health (AREA)
- Veterinary Medicine (AREA)
- Magnetic Resonance Imaging Apparatus (AREA)
Abstract
The invention relates to a nuclear magnetic resonance permanent magnet, comprising: the first Halbach magnet is in an annular column shape, and a column-shaped cavity is formed in the middle of the first Halbach magnet; the core magnet is arranged in the cylindrical cavity of the first Halbach magnet and comprises an end magnet, an intermediate body, an end magnet and a positioning tube sleeved outside the end magnet, the intermediate body and the end magnet which are sequentially overlapped; the end magnet is an annular columnar magnet with a columnar cavity in the middle, and consists of axial magnetic blocks and lateral magnetic blocks which are alternately overlapped; the magnetic direction of the middle part of the core magnet is consistent with that of the first Halbach magnet. Compared with the prior art, the core magnet has a unique end magnet structure, the end magnets arranged in pairs contribute to the magnetic field intensity of the first Halbach magnet in the cavity of the core magnet, the magnetic field distribution in the cavity of the magnet is changed, the magnetic field which is approximately evenly distributed in the length of 1/2 of the cavity is compressed to the interval of about 1/6, the volume of the magnet can be effectively reduced, and the cost is saved.
Description
Technical Field
The invention relates to the technical field of nuclear magnetic resonance, in particular to a nuclear magnetic resonance permanent magnet.
Background
Nuclear magnetic resonance spectroscopy (NMR spectroscopy) is a tool used for quantitative analysis of substances, research of molecular structures and molecular dynamics, and is widely applied to various fields of analytical chemistry, structural biology, food and plant science, pharmacy or forensics, and the like. Permanent magnets used in nuclear magnetic resonance equipment mostly adopt permanent magnet H-shaped or C-shaped structures composed of iron yokes, permanent magnet blocks, shimming polar plates and the like. Such magnets are bulky and heavy due to the presence of the iron yoke and have a limited magnetic field strength. The novel iron-yoke-free multipolar cylindrical Halbach magnet structure formed by rare earth materials has the advantages of higher magnetic field intensity, closed magnetic flux, small dissipation field and small mutual interference with the environment compared with the traditional permanent magnet design in structure and magnetic field intensity. However, the Halbach magnet structure in the prior art still has the technical problems of larger volume and poor magnetic field uniformity, and cannot meet the requirement of further miniaturization of nuclear magnetic resonance spectrum equipment to the size of a coffee cup.
Disclosure of Invention
The present invention aims to overcome at least one of the above-mentioned drawbacks of the prior art by providing a nuclear magnetic resonance permanent magnet.
In the nuclear magnetic resonance permanent magnet designed by the invention, the end magnetic structure comprises two axial magnetic blocks and two lateral magnetic blocks, and the unique structure changes the magnetic distribution on the axial path from the original steamed bread shape to the mountain-head shape, see fig. 12 and 13, thus improving the magnetic field intensity, and shortening the axial height, thereby reducing the volume. Specifically, the end magnets arranged in pairs in the invention can improve the magnetic field intensity in the magnetic direction of the first Halbach magnet in the middle cavity of the core magnet, so that when the same level of magnetic field intensity is required to be provided, the invention can lead the volume required by the nuclear magnetic resonance permanent magnet designed by the invention to be smaller than that of the Halbach magnet in the prior art by shortening the axial height of the core magnet. The addition of two ferromagnetic pole heads with parallel gaps improves the magnetic uniformity, and the original thousands of ppm is conveniently reduced by hundreds of ppm, even tens of ppm. The second intermediate shown in fig. 8 has greatly improved magnetic field strength because of the addition of two parallel ferromagnetic pole tips to improve magnetic uniformity and reduce the gap of the magnetic field from original circular shape to a distance of 2 parallel ferromagnetic pole tips. The space between the ferromagnetic pole head and the positioning tube can be used for subsequent component matching of the instrument.
The aim of the invention can be achieved by the following technical scheme:
a nuclear magnetic resonance permanent magnet comprising:
the first Halbach magnet is in an annular column shape, and a column-shaped cavity is formed in the middle of the first Halbach magnet;
the core magnet is arranged in the cylindrical cavity of the first Halbach magnet and comprises an end magnet, an intermediate body, an end magnet and a positioning tube sleeved outside the end magnet, the intermediate body and the end magnet which are sequentially overlapped;
the end magnet is an annular columnar magnet with a columnar cavity in the middle, and consists of axial magnetic blocks and lateral magnetic blocks which are alternately overlapped; preferably, the axial magnetic blocks and the lateral magnetic blocks are two, and the columnar end magnetic blocks are formed after the two magnetic blocks are alternately overlapped. The end magnetic combination formed by the positioning tube and the two end magnets has a contribution magnetic direction consistent with that of the first Halbach magnet;
the magnetic direction of the middle part of the core magnet is consistent with that of the first Halbach magnet.
Further, the first intermediate is made of rare earth permanent magnet material, and the magnetic direction of the first intermediate is consistent with that of the first Halbach magnet. More specifically, the first Halbach magnet material is a rare earth permanent magnet, providing about 2/3 of the magnetic properties of the nuclear magnetic resonance permanent magnet designed according to the present invention. The length of the core magnet is not necessarily aligned with the height of the first Halbach magnet, the core magnet providing about 1/3 of the magnetic properties of the nuclear magnetic resonance permanent magnet designed according to the invention; the positioning tube restrains the two end magnets and an intermediate body in the tube to form a complete core magnet, and the core magnet is fixed in the center of the first Halbach magnet.
Further, the intermediate has two structures, including a first intermediate or a second intermediate.
Further, the first intermediate is a second Halbach magnet with a cylindrical cavity in the middle, and the outer diameter and the inner diameter of the second Halbach magnet are the same as those of the end magnet.
Further, the second Halbach magnet is made of rare earth permanent magnet material, and the magnetic direction of the second Halbach magnet is consistent with that of the first Halbach magnet.
Further, the second intermediate body is composed of ferromagnetic pole heads arranged in parallel and positioning blocks arranged between the adjacent ferromagnetic pole heads, and magnetic uniformity is improved through the ferromagnetic pole heads arranged in the second intermediate body.
Further, the positioning block is made of non-magnetic materials or rare earth permanent magnetic materials.
Further, when the positioning block is made of rare earth permanent magnet materials, the magnetic direction of the positioning block is opposite to that of the first Halbach magnet.
Further, the first Halbach magnet is formed by arranging and combining a plurality of magnetic blocks with sector ring structures in an annular Halbach permanent magnet array.
Further, the number of the magnetic blocks composing the sector ring structure of the first Halbach magnet is even. Preferably, the number of magnetic blocks constituting the sector ring structure of the first Halbach magnet is 8, 10 or 12.
Further, iron rings are sleeved on end magnets at two ends of the core magnet to change the magnetic circuit, so that magnetic shielding is facilitated. In engineering, a ferromagnetic material and a high magnetic conduction material are commonly used as magnetic shielding materials, and the end magnet is provided with a ferric ring so that the external magnetic force lines of the end magnet change directions and pass through the ferric ring, and the magnetic shielding materials are not externally dispersed any more, thereby being beneficial to magnetic shielding at the position. The magnetic influence of the nuclear magnetic resonance permanent magnet on the outside is reduced, and the damage to instruments or personal injury is avoided.
Further, the length of the core magnet sleeved with the iron ring is larger than that of the first Halbach magnet, and the iron ring is positioned at the part of the end magnet extending out of the first Halbach magnet.
Compared with the prior art, the invention has the following advantages:
(1) In the nuclear magnetic resonance permanent magnet designed by the invention, the core magnet has a unique end magnet structure, and the end magnet consists of axial magnetic blocks and lateral magnetic blocks which are alternately overlapped. The end magnets arranged in pairs contribute to the magnetic field strength of the first Halbach magnet in the cavity of the core magnet middle body in the magnetic direction, change the magnetic field distribution in the cavity of the magnet, compress the magnetic field which is almost evenly distributed in the length of 1/2 cavity into the interval of about 1/6, thereby effectively reducing the volume of the magnet and saving the cost.
(2) The space in the nuclear magnetic resonance permanent magnet designed by the invention is used for placing instrument accessories and parts.
(3) In the nuclear magnetic resonance permanent magnet designed by the invention, the iron rings are sleeved on the end magnets at the two ends of the core magnet, so that the magnetic shielding is facilitated, and the magnetic uniformity of the magnetic field in the nuclear magnetic resonance permanent magnet is improved.
(4) The nuclear magnetic resonance permanent magnet designed by the invention can be applied to miniaturization of nuclear magnetic resonance spectrum equipment.
Drawings
FIG. 1 is a schematic diagram of a permanent magnet for nuclear magnetic resonance in example 1;
FIG. 2 is a schematic view of an outer magnet in example 1;
FIG. 3 shows the magnetic direction of the core magnet in example 1;
FIG. 4 is a schematic diagram showing the magnetic directions of the end magnet and the intermediate in the core magnet of example 1;
FIG. 5 is a schematic diagram of the end magnet and the magnetic direction thereof in example 1;
FIG. 6 is a top view of the end magnetic direction in example 1;
FIG. 7 is a schematic diagram showing the structure and magnetic direction of the first intermediate in example 1;
FIG. 8 is a schematic structural diagram of a second intermediate in example 2;
FIG. 9 is a schematic view of the end magnet with iron ring and the magnetic direction thereof in example 3;
FIG. 10 is a top view of the end magnetic direction of the band in example 3;
FIG. 11 is a schematic diagram showing the assembly of a NMR permanent magnet with end magnets of the iron ring in example 3;
FIG. 12 shows the magnetic distribution on the axis of a Halbach magnet of the prior art
FIG. 13 is a magnetic distribution on the axis of a permanent magnet for nuclear magnetic resonance in example 3;
the reference numerals in the figures indicate: 1-a first Halbach magnet; 2-core magnetism; 21-positioning a tube; 22-end magnetic; 221-axial magnetic blocks; 222-lateral magnet; 223-iron ring; 23-intermediates; 231-a first intermediate; 2311-a second Halbach magnet; 232-a second intermediate; 2321-ferromagnetic pole head; 2322-positioning block.
Detailed Description
The invention will now be described in detail with reference to the drawings and specific examples. The present embodiment is implemented on the premise of the technical scheme of the present invention, and a detailed implementation manner and a specific operation process are provided, but the protection scope of the present invention is not limited to the following embodiments.
Example 1
A nuclear magnetic resonance permanent magnet, see fig. 1, consists of a first Halbach magnet 1 and a core magnet 2. The number of the magnetic blocks composing the first Halbach magnet 1 is not specified, and 8 magnetic blocks with a sector-shaped annular structure are selected to compose the first Halbach magnet 1 in the embodiment. The material of the first Halbach magnet 1 is a rare earth permanent magnet whose magnetic direction is shown in fig. 2, which provides 2/3 of the majority of the magnetism of the present magnetic resonance permanent magnet.
In detail, see fig. 1, a cylindrical core magnet 2 is placed in a cylindrical cavity in the middle of the first Halbach magnet 1, the length of which is not necessarily aligned with the height of the first Halbach magnet 1, see fig. 9. The core magnet 2 provides a magnetic direction which corresponds to the magnetic direction provided by the Halbach magnet 1.
Referring to fig. 3 in detail, the core magnet 2 is composed of a positioning tube 21, two end magnets 22 and an intermediate body 23. The core magnetism provides about 1/3 of the magnetism for the present magnetic resonance permanent magnet.
Referring to fig. 4 in detail, the end magnet assembly consisting of the positioning tube 21 and the 2 end magnets 22 contributes to a magnetic direction which is identical to the magnetic direction of the first Halbach magnet 1. Each end magnet 22 consists of two axial magnetic blocks 221 and two lateral magnetic blocks 222, and the end magnet structure and the magnetic direction are shown in fig. 5 and 6.
Referring to fig. 7 in detail, in this embodiment, the intermediate body 23 is a first intermediate body 231, the first intermediate body 231 is a second Halbach magnet 2311 with a cylindrical cavity in the middle, the material is also a rare earth permanent magnet, the outer diameter and the inner diameter are the same as those of the end magnet 22, and the magnetic direction is shown in fig. 7.
Example 2
In this embodiment, the nmr permanent magnet is substantially the same as embodiment 1, except that the intermediate body 23 in this embodiment has a second intermediate body 232, and is composed of two ferromagnetic pole heads 2321 and two positioning blocks 2322, as shown in fig. 8. The positioning block 2322 may be made of a non-magnetic material or a rare earth permanent magnet, and the magnetic direction of the rare earth permanent magnet block is opposite to that of the first Halbach magnet 1. The addition of the ferromagnetic pole head is beneficial to improving the body magnetic uniformity of the nuclear magnetic resonance permanent magnet.
The addition of the two parallel ferromagnetic pole heads with gaps in the embodiment improves the magnetic uniformity of the magnetic field of the nuclear magnetic resonance permanent magnet, and the original thousands of ppm is conveniently smaller by hundreds of ppm, even tens of ppm. The second intermediate body 232 shown in fig. 8 has a greatly improved magnetic field strength because of the addition of two parallel ferromagnetic pole tips with a gap that improves magnetic uniformity and reduces the gap of the magnetic field from an original circular shape to a distance between the two parallel ferromagnetic pole tips. The space between the ferromagnetic pole head 2321 and the positioning tube 21 may be used for subsequent component matching of the instrument.
Example 3
The nmr permanent magnet in this embodiment is substantially identical to embodiment 2, except that in this embodiment, the end magnet 22 is sleeved with an iron ring 223, and in this case, the length of the core magnet 2 sleeved with the iron ring is longer than the length of the first Halbach magnet 1, and the iron ring is located at a portion of the end magnet 22 extending beyond the first Halbach magnet 1 of the magnet, as shown in fig. 9-11. Specifically, in this embodiment, an iron ring 223 is attached to the original end magnet 22 to change the magnetic circuit, which is beneficial to magnetic shielding. In engineering, a ferromagnetic material and a high magnetic conduction material are commonly used as magnetic shielding materials, and the end magnet 22 is provided with the iron ring 223 to change the direction of magnetic force lines of the end magnet to the outside, so that the magnetic force lines pass through the iron ring 223 without diverging to the outside, the magnetic shielding of the position is facilitated, the magnetic influence of the nuclear magnetic resonance permanent magnet on the outside is reduced, and the instrument damage or personal injury is avoided.
The magnetic distribution on the axis of Halbach magnets in the prior art is shown in fig. 12. The first Halbach magnet 1 provided with the core magnet 2 in this embodiment, namely the nmr permanent magnet designed in this embodiment, has a magnetic distribution on the axis shown in fig. 13. Due to the unique end magnetic structure in the embodiment, the end magnetic body 22 is composed of the axial magnetic blocks 221 and the lateral magnetic blocks 222 which are alternately overlapped, the end magnetic bodies 22 which are arranged in pairs contribute to the magnetic field strength of the core magnetic body 2 in the magnetic direction of the first Halbach magnet 1 in the cavity of the second intermediate body 232, the magnetic field distribution in the cavity of the magnet is changed, and the magnetic field which is almost evenly distributed at the height of 1/2 cavity is compressed into the interval of about 1/6, so that the volume of the magnet can be effectively reduced, and the cost is saved.
The above description is only a preferred embodiment of the present invention, and is not intended to limit the invention in any way, and any person skilled in the art may make modifications or alterations to the disclosed technical content to the equivalent embodiments. However, any simple modification, equivalent variation and variation of the above embodiments according to the technical substance of the present invention still fall within the protection scope of the technical solution of the present invention.
Claims (10)
1. A nuclear magnetic resonance permanent magnet, comprising:
the first Halbach magnet (1) is in an annular column shape, and a column-shaped cavity is arranged in the middle;
the core magnet (2) is arranged in the cylindrical cavity of the first Halbach magnet (1) and comprises an end magnet (22), an intermediate body (23) and the end magnet (22) which are sequentially overlapped, and a positioning tube (21) sleeved outside the end magnet, the intermediate body and the end magnet;
the end magnet (22) is an annular columnar magnet with a columnar cavity in the middle, and consists of axial magnetic blocks (221) and lateral magnetic blocks (222) which are alternately overlapped;
the magnetic direction of the core magnet (2) is consistent with that of the first Halbach magnet (1).
2. A nuclear magnetic resonance permanent magnet according to claim 1, characterized in that the material of the first Halbach magnet (1) is a rare earth permanent magnet material providing at least half the magnetism of the nuclear magnetic resonance permanent magnet.
3. A nuclear magnetic resonance permanent magnet according to claim 1, characterized in that the intermediate body (23) has two structures, including a first intermediate body (231) or a second intermediate body (232).
4. A permanent magnet according to claim 3, characterized in that the first intermediate body (231) is a second Halbach magnet (2311) with a cylindrical cavity in the middle, the outer diameter and inner diameter of which are the same as the end magnets (22).
5. A nuclear magnetic resonance permanent magnet according to claim 3, characterized in that the material of the second Halbach magnet (2311) is a rare earth permanent magnet material, the magnetic direction of which corresponds to the first Halbach magnet (1).
6. A permanent magnet according to claim 3, wherein the second intermediate body (232) is composed of ferromagnetic pole heads (2321) arranged in parallel and positioning blocks (2322) arranged between adjacent ferromagnetic pole heads (2321).
7. A permanent magnet according to claim 6, wherein the positioning block (2322) is made of a non-magnetic material or a rare earth permanent magnet material.
8. The nmr permanent magnet of claim 7, wherein the positioning block (2322) is made of rare earth permanent magnet material, and the magnetic direction of the positioning block (2322) is opposite to the magnetic direction of the first Halbach magnet (1).
9. A permanent magnet according to claim 1, characterized in that the end magnets (22) at both ends of the core magnet (2) are provided with iron rings.
10. A nuclear magnetic resonance permanent magnet according to claim 9, characterized in that the length of the core magnet (2) around which the iron ring is fitted is greater than the length of the first Halbach magnet (1), the iron ring being located at the part of the end magnet (22) extending beyond the first Halbach magnet (1).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311095475.9A CN117253689A (en) | 2023-08-29 | 2023-08-29 | Nuclear magnetic resonance permanent magnet |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311095475.9A CN117253689A (en) | 2023-08-29 | 2023-08-29 | Nuclear magnetic resonance permanent magnet |
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| Publication Number | Publication Date |
|---|---|
| CN117253689A true CN117253689A (en) | 2023-12-19 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202311095475.9A Pending CN117253689A (en) | 2023-08-29 | 2023-08-29 | Nuclear magnetic resonance permanent magnet |
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| Country | Link |
|---|---|
| CN (1) | CN117253689A (en) |
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2023
- 2023-08-29 CN CN202311095475.9A patent/CN117253689A/en active Pending
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