CN1932545A - Permanent magnet used for portable nuclear magnetic resonance instrument magnetostatic field generator - Google Patents
Permanent magnet used for portable nuclear magnetic resonance instrument magnetostatic field generator Download PDFInfo
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- CN1932545A CN1932545A CN 200510086407 CN200510086407A CN1932545A CN 1932545 A CN1932545 A CN 1932545A CN 200510086407 CN200510086407 CN 200510086407 CN 200510086407 A CN200510086407 A CN 200510086407A CN 1932545 A CN1932545 A CN 1932545A
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Abstract
One kind used for then the hold type nuclear magnetic resonance instrument quiet the magnetic field take place equip of always body, from a hollow cylinder form always body and a hollow hemisphere form always body constitute, hemisphere form the stalk of body always cuts one that the noodles folds to impose a cylinder form always a body to carry noodles up. Hollow cylinder form always body from shape homology, the magnetic field strength is equal, magnetizing a direction to revolve a direction for the body double and fan-shaped the body always constitutes. Hemisphere form always body is with the outside path be equal to a cylinder form a body always of outside path, inside path small in cylinder form always body of inside path, the stalk runs parallel with the semicircle wreath of magnetic field direction, the stalk which rounds to run parallel with a magnetic field direction revolves to get of, the hemisphere's form the body always closes the cylinder form body to carry a department at hollow type cylinder form the outside side of the body at the right moment. Hemisphere form always body and cylinder form the body always compensates a cylinder form consistently and in order to a body to always carry the horizontal magnetic field of department in the on-line magnetic field direction of the cylinder stalk inside the chamber.
Description
Technical field
The present invention relates to be used for the permanent magnet of nuclear magnetic resonance apparatus, particularly be used for the permanent magnet of portable nuclear magnetic resonance instrument magnetostatic field generator.
Background technology
In recent years, obtained continuous development, proposed many important use directions, and constantly realized in the nuclear magnetic resonance equipment field.
Current measurement to the test core sample, the method for employing are to obtain rock core by open-air probing earlier, rock core is taken back in the laboratory that measurement environment is had relatively high expectations measured again.The defective of this method is to finish required overlong time from the measurement that acquires of rock core, so that the income analysis result is effective poor because of it, can not be effectively applied to instruct field survey and exploitation.Therefore realize that the physicochemical characteristics of obtaining the rock core sample fast has realistic meanings.Also by the same token, the in-site measurement of agricultural product and food quality detection and chemical products etc. also need portable nuclear magnetic resonance instrument.
Magnetostatic field generator (magnetic source) is the important component part of nuclear magnetic resonance apparatus (NMR).It is how high that the matter of utmost importance that makes up portable NMR device is not that magnetic field intensity has, but need size, the weight of the magnetic field intensity, uniformity coefficient and the entire equipment that are fit to.Portable nuclear magnetic resonance instrument requires magnet that suitable magnetic field intensity and uniformity coefficient can be provided, and reduces the size and the weight of entire equipment as far as possible.
Seven parts of Chinese patents by retrieval:
1) patent No. is 92112454.6 " Nd-Fe-B magnet for permanent-magnet nuclear magnetic resonance spectrometer ";
2) patent No. is 98113543.9 " permanent magnet for NMR imaging instrument ";
3) patent No. is 98318945.5 " nuclear magnetic resonance C shape permanent magnets ";
4) patent No. is 01128381.5 " a kind of permanent magnet that is used for NMR imaging instrument ";
5) patent No. is 02290346.1 " rare earth permanent magnet formula mass spectrum of nuclear magnetic resonance instrument magnetic field device ";
6) patent No. is 200410030688.4 " being suitable for the permanent magnet that the portable nuclear magnetic resonance device uses ";
7) patent No. is 200510011970.2 " permanent magnets that are used for portable nuclear magnetic resonance instrument ".
The magnet of the first six part patent is by magnet steel, pole plate or grading ring, and formations such as yoke, a pair of permanent magnet block is installed on two relative upper and lower yokes, on the described a pair of permanent-magnet surfaces opposite to each other pole plate is installed respectively.Above-mentioned prior art all adopts the framework of polar-plate-type, it is characterized in that obtaining required magnetic field space by two opposite magnetic pole of magnetic circuit closed structure.Its weak point is:
(1) the uniform magnetic field spatial volume is little, and the magnetic field space waste is too big.Because very strict, existingly meet homogeneous area that field intensity requires and be generally between two magnetic poles in the magnet cross section about 30% of air-gap field even lower the uniformity requirement in magnetic field.If end effect around considering, the utilization factor of magnetic field space is lower.This is one of very high basic reason of magnet cost expense.
(2) magnetic field intensity is difficult to improve.Permanent magnet block is installed on two relative upper and lower yokes, so the distribution of magnetic source is restricted, and according to the superposition principle in magnetic field, the raising of magnet center field intensity is limited.Because outwards reveal in magnetic field, magnetic field intensity is less than the permanent magnetic material remanent flux density.
(3) in the design of magnet, need constitute the closed magnetic field loop by yoke, but also need to adopt pole plate or grading ring to improve the interior uniformity of magnetic field of magnet gap, this just unavoidably increases many ferromagnetic materials, not only increased the cost of instrument, increased magnet volume and weight especially to a large extent, be unfavorable for carrying.
The 7th part of patent documentation, the patent No. is 200510011970.2 " permanent magnet that is used for portable nuclear magnetic resonance instrument ", cylindrical permanent magnet and half cylindrical magnet by a hollow constitute, the shaft section of half-cylindrical magnet is superimposed upon on the end face of cylindrical permanent magnet, half-cylindrical magnet is consistent with cylindrical magnet magnetic direction on the axis in cylindrical cavity, in order to the magnetic field of compensation cylindrical magnet end.When this patent is applied in portable nuclear magnetic resonance instrument, overcome the deficiency of polar-plate-type framework, the volume of the magnet that has reduced has effectively alleviated weight, and the magnetic field in the magnet hollow cavity obtains compensation.What but the permanent magnet of this patent design adopted is the magnetic field of half-cylindrical permanent magnet compensation cylindrical magnet end, has following 2 deficiencies:
1) the half-cylindrical magnet that has only endless along its axially on, each amount in magnetic field could evenly distribute, thereby realize the magnetic field in the cylindrical magnet hollow cavity is effectively compensated, but in the reality, the axial length of half-cylindrical magnet is limited, and therefore inevitably there is systematic error in this compensation scheme;
2) magnetic field, both ends of half-cylindrical magnet becomes to disperse distribution in the space, has very big leakage field, therefore actual environment for use is had relatively high expectations, still be not well positioned to meet portable NMR instrument the few leakage field of magnet design proposition or the requirement of magnetic leakage free.
Current when carrying out Nuclear Magnetic Resonance Measurement, most research techniques all is that the sample test tube of packing into is measured, therefore portable nuclear magnetic resonance instrument needs a kind of magnetic field space utilization factor height, uniformity coefficient height, volume is little, in light weight, leakage field is few, is applicable to the permanent-magnet that sample in the test tube is measured.
Summary of the invention
The objective of the invention is to overcome the shortcoming of existing portable nuclear magnetic resonance instrument magnet, a kind of test tube shaped permanent magnet is provided.The magnetic field space utilization factor height of this permanent magnet, the volume of magnet is little, in light weight, leakage field is few.Be applicable to the detection of portable nuclear magnetic resonance instrument to sample in the test tube.
For achieving the above object, the present invention adopts following technical scheme:
Test tube shaped permanent magnet of the present invention is made of the cylindrical permanent magnet of a hollow and the semisphere permanent magnet of a hollow, cylindrical permanent magnet is identical with the overall diameter of semisphere permanent magnet, and the shaft section of semisphere permanent magnet is superimposed upon on the end face of cylindrical permanent magnet.The cylindrical permanent magnet of hollow along the circumferential direction is divided into N=2
M(M is the integer greater than 2) piece cylinder permanent magnet, every cylinder permanent magnet shape is identical, shaft section is fan-shaped, magnetic field intensity equates, at cylindrical-coordinate system (r, , z) in, cylindrical magnet is got the Z axle as cylindrical axial, the direction of magnetization of cylinder permanent magnet is vertical with the Z axle, the direction of magnetization at N piece cylinder permanent magnet any center wherein is decided to be radial direction (=0), and other N-1 piece cylinder permanent magnet changes according to β ()=2 , and is the coordinate components in cylindrical-coordinate system of every cylinder permanent magnet.Constitute the cylindrical permanent magnet of a complete hollow between the N piece cylinder permanent magnet by the seccotine adhesion, forming magnetic direction in the cylindrical permanent magnet of hollow is =0 and two perpendicular pole fields of axle, and every cylinder permanent magnet is divided into one group of plurality of small blocks cylinder permanent magnet vertically in the mill.
On end face of cylindrical permanent magnet, be axle with the diameter parallel with cylindrical permanent magnet internal magnetic field direction, annulus on the end face is cut into two semicircular ring, each semicircular ring is made up of the fan-shaped annulus of N/2+1 piece.Get the external diameter that the semicircular ring external diameter equals cylindrical permanent magnet, the internal diameter of semicircular ring is less than the internal diameter of cylindrical permanent magnet.With above-mentioned diameter is axle, and semicircular ring is rotated π, and the space that this semicircular ring is inswept constitutes a hemisphere, and the semisphere magnet is divided into the U group, and so every group of hemisphere formed by semicircular ring rotation π/U angle, and every group is (N/2+1) fritter sphere permanent magnet.The shaft section of semisphere permanent magnet is superimposed upon on the end face of cylindrical permanent magnet.On the shaft section of semisphere permanent magnet and cylindrical permanent magnet stack, the direction of magnetization of the cylinder permanent magnet that the direction of magnetization of the U fritter sphere permanent magnet that joins with the cylinder permanent magnet is joined with it is identical, and remaining fritter sphere permanent magnet magnetization direction is by following rule; Spheric coordinate system (r, , θ) in, each magnetic patch in same group of fritter sphere permanent magnet has identical α (θ)=θ direction of magnetization on the θ direction; On the direction, the direction of magnetization of the magnetic patch in same group changes according to β ()=2 .Constitute the semisphere permanent magnet of a complete hollow between this (N/2+1) * U piece sphere permanent magnet by the seccotine adhesion, forming magnetic direction in the semisphere permanent magnet of hollow is =0, two pole fields of θ=pi/2.
This semisphere permanent magnet is positioned at the end of the outside closed circular cylindrical magnet of hollow type cylindrical magnet.The semisphere permanent magnet is consistent with the transverse magnetic field direction of cylindrical permanent magnet in cylindrical cavity, both transverse magnetic fields along separately axially outwards gradually the decay, and have identical die-away curve, so the semisphere permanent magnet can be in order to the transverse magnetic field of a side in the compensation cylindrical permanent magnet cavity.Whole magnet after the combination constitutes test tube shaped.It in the cavity of test tube shaped permanent magnet uniform transverse magnetic field.
The principle of the invention is as follows:
Outside the r ball＞insert rare-earth permanent magnet in the spheroid in the ball, spheric coordinate system (r, , θ) in, the direction of magnetization of permanent magnet changes according to following formula:
β()＝2 (1)
α(θ)＝θ (2)
, θ: the sense of rotation of permanent magnet own,
Obtain the spheroid internal magnetic field:
Wherein:
r
Outside the ball: the external diameter of spheroid;
r
In the ball: the internal diameter of spheroid;
Br: the remanent magnetism of rare earth permanent-magnetic material.
Spherical permanent magnet can produce a uniform magnetic field in spherical cavity, the stray field of spheroid outside is zero.Ideally, for intensity and uniformity coefficient, magnetic field equates everywhere in the inner chamber of spherical permanent magnet.
Outside the r post＞insert rare-earth permanent magnet in the right cylinder in the r post, face of cylinder coordinate system (r, , z) in, the direction of magnetization of permanent magnet changes according to following formula:
β()＝2 (4)
: the sense of rotation of permanent magnet own,
Obtain the right cylinder internal magnetic field:
B
Post=Brln (r
Outside the post/ r
In the post) (5)
Wherein:
r
Outside the post: cylindrical external diameter;
r
In the post: cylindrical internal diameter;
Such cylindrical permanent magnet can produce a transverse magnetic field that is orthogonal to cylinder axis in cylindrical cavity, the stray field of right cylinder circumference outside is zero.For intensity and uniformity coefficient, this magnetic field is uniqueness and perfect at two-dimensional space, and magnetic field equates everywhere in the inner chamber of cylindrical permanent magnet.When guaranteeing identical shimming size, the magnetic field space of the test tube shaped magnet that is made of semisphere and cylindrical magnet is far smaller than the magnetic field space of polar-plate-type magnet, and the magnetic field space utilization factor is big, must cause the test tube shaped magnet weight light, and volume is little.Be suitable as very much the magnetostatic field generator of portable nuclear magnetic resonance instrument.
Here need to prove: if the direction of magnetization of every bit can change continuously by the sense of rotation of given magnet own in the magnet, the unevenness in whole in theory hollow circular cylinder internal magnetic field space is zero, in the actual engineering owing to the process for machining and manufacturing reason, can't accomplish that at present direction of magnetization changes continuously by the sense of rotation of given magnet own, therefore adopt the magnet block division method.The piece number of magnet five equilibrium is many more, more near ideal state.
But in the three dimensions of cylindrical permanent magnet, along axis direction, decay gradually in Distribution of Magnetic Field mind-set two ends from magnet, if the magnet long enough, magnetic field equals half of magnet center field intensity on both ends of the surface so.
In actual use in order to obtain enough uniformity coefficient spaces, need to guarantee certain axial dimension length.But the actual magnetic field space that uses has only and satisfies in the middle of the right cylinder that uniformity coefficient requires one section.When the sample in the test tube was put into probe measurement, the space of magnet lower end was wasted, and had both increased volume, had also increased weight.Weakened the advantage that cylindrical permanent magnet is used in portable nuclear magnetic resonance instrument.
Therefore, for the transverse magnetic field decay gradually vertically that compensates cylindrical permanent magnet, we are analyzed as follows cylindrical permanent magnet.When the position of endless cylindrical permanent magnet, cut by the x-y plane at z=0.If V
z(r
r,
r, z
r) be scalar potential by the cylindrical permanent magnet generation of z＞0, V
z(r
l,
l, z
l) be scalar potential by the cylindrical permanent magnet generation of z＜0, if V
z(r, are the scalar potentials of endless cylindrical permanent magnet z), and following formula is obviously set up so:
V
z(r
r，
r，z
r)+V
z(r
l，
l，z
l)＝V
z(r，，z) (6)
Use certain operator to (4) formula, obtain interested flow function F
z(r, , z),
F
z(r
r，
r，z
r)+F
z(r
l，
l，z
l)＝F
z(r，，z) (7)
In like manner, when obtaining spherical permanent magnet x-y plane and cutting, interested flow function
F
r(r，，θ)，
F
r(r
u，
u，θ
u)+F
r(r
d，
d，θ
d)＝F
r(r，，θ) (9)
When the end face field intensity of cylindrical permanent magnet equates with the field intensity in semisphere permanent magnet cross section, and direction is when identical, and effectively the transverse magnetic field of compensation cylindrical permanent magnet is decayed vertically.Therefore, we select:
F
r(r
d，
d，0)＝F
z(r
r，
r，0) (11)
F
r(r
d，
d，0)+F
z(r
r，
r，0)＝F
z(r，，z) (12)
By (3), (5) Shi Kede:
Can get by following formula:
Therefore, as long as the interior external radius of the interior external radius of the semisphere magnet of choosing and cylindrical magnet satisfies the relation of (14) formula, just can compensate the cylindrical permanent magnet transverse magnetic field and decay vertically.The internal diameter r of cylindrical permanent magnet
In the postSize depend on the size of the test tube and the radio-frequency coil of splendid attire sample, the external diameter r of cylindrical permanent magnet
Outside the postDesign field intensity by instrument decides by (5) formula, in order to reduce the outside stray field intensity of magnet, selects the external diameter of spherical magnet to equal the external diameter of cylindrical magnet usually, determines the internal diameter of spherical magnet then by (14) formula.
This shows if with the magnetic field superposition of two kinds of magnets, be equivalent to the axial length of cylindrical permanent magnet is prolonged one times, therefore can effectively improve the axial magnetic field uniformity coefficient, also alleviate the weight of magnet simultaneously, reduce volume.
The magnetic field of test tube shaped magnet of the present invention circumferentially is being limited in the circumference, can not outwards disperse, and leakage field is less, present a kind of poly-magnetic effect, thereby the magnetic field intensity in the test tube shaped magnet can design than the magnetic field intensity height of polar-plate-type magnet, thereby improves the resolution of instrument.
Because the adding of semisphere permanent magnet, the shimming district of the central cross-section in magnetic field increases, and the center of departing from cylindrical permanent magnet, semisphere permanent magnet skew downwards.Just because of the skew in shimming district, this combination magnet center and the increase of axial dimension, so the present invention can make the suitable more detection to sample in the test tube of this test tube shaped magnet.
The invention has the advantages that: the magnetic field space utilization factor is big, uniformity coefficient is high, volume is little, in light weight, leakage field is little, be fit to the measurement to sample in the test tube.
Description of drawings
Fig. 1 is the structural representation of the specific embodiment of the invention.Among the figure: cylindrical permanent magnet by Z1, Z2, Z3, Z4, Z5, Z6, Z7, Z8 totally 8 groups of cylinder shape permanent magnets constitute; The semisphere permanent magnet by Q1, Q2, Q3, Q4, Q5 totally 5 groups of sphere shape permanent magnets constitute.
Fig. 2 is the specific embodiment of the invention synoptic diagram of the cylindrical permanent magnet of 8 groups of magnets compositions.
Fig. 3 is the specific embodiment of the invention synoptic diagram that 5 groups of magnets are formed the semisphere permanent magnet.
Embodiment
The present invention is described further below in conjunction with the drawings and specific embodiments.
Fig. 1 is the structural representation of the specific embodiment of the invention.As shown in Figure 1, the magnetic patch that will have identical direction of magnetization is divided into one group, and obtaining 8 groups of shaft sections altogether is fan-shaped cylinder magnet: Z1, Z2, Z3, Z4, Z5, Z6, Z7, Z8; With the diameter parallel with cylindrical permanent magnet internal magnetic field direction is axle, annulus on the end face is cut into two semicircular ring, is axle with semicircle with above-mentioned diameter, and the sphere shape permanent magnet that obtains that rotates a certain angle is divided into one group, obtains 5 groups of sphere shape permanent magnets altogether: Q1, Q2, Q3, Q4, Q5.The interior transverse magnetic field direction of magnetic direction in the cylindrical permanent magnet and semisphere permanent magnet is identical.The end face of cylindrical permanent magnet and the shaft section of semisphere permanent magnet are superimposed, adopt bolted to connect, and are combined into the test tube shaped magnet.
Figure 2 shows that the embodiment of the cylindrical permanent magnet that 8 groups of magnets of the present invention are formed.It is that fan-shaped permanent magnet Z1, Z2, Z3, Z4, Z5, Z6, Z7, Z8 constitutes that cylindrical magnet is divided into 8 groups xsect by circumferencial direction.Every group of magnet is identical by direction of magnetization, and cylinder magnetic patch of the same size claims one group of magnet by the seccotine adhesion vertically.8 groups of direction of magnetization are inequality, and cylinder magnet of the same size by the seccotine adhesion, constitutes the cylindrical permanent magnet of a hollow along circumferentially.
As shown in Figure 2, be followed successively by in the direction of the clock in the cylindrical permanent magnet and respectively organize magnetic patch numbering Z1, Z2, Z3, Z4, Z5, Z6, Z7, Z8, each magnitude of field intensity of organizing magnet is identical.Get the magnetic patch group that is numbered Z1, the direction of magnetization of this magnetic patch is taken as points to the center of circle radially.So according in the direction of the clock, the direction of magnetization of Zi the magnetic patch angle beta that turns clockwise then
i=(i-1) pi/2 (i=1,2,3 ... 8).Solid arrow is depicted as and respectively organizes the magnetic patch direction of magnetization among Fig. 2, and hollow arrow is a cylindrical permanent magnet internal magnetic field direction.
Figure 3 shows that the embodiment of the semisphere permanent magnet that 5 groups of magnets of the present invention are formed.The semisphere permanent magnet by Q1, Q2, Q3, Q4, Q5 totally 5 groups of sphere shape permanent magnets constitute.Therefore, spheric coordinate system (r, , θ) in, each magnetic patch in same group of magnet has identical α (θ)=θ direction of magnetization on the θ direction; On the direction, the direction of magnetization of the magnetic patch in same group changes according to β ()=2 .Constitute a semisphere permanent magnet by the seccotine adhesion.
As shown in Figure 3, be followed successively by each magnetic patch group # Q1, Q2, Q3, Q4, Q5 in the semisphere permanent magnet in the direction of the clock, each magnitude of field intensity of organizing magnetic patch is identical.In Fig. 3, provide each the magnetic patch direction of magnetization of magnetic patch group that is numbered Q1, shown in solid arrow, the direction of magnetization on the θ direction of this magnetic patch group is taken as α (θ)=0.So according in the direction of the clock, the direction of magnetization angle [alpha] that turns clockwise on the θ direction of Qi magnetic patch then
i=(i-1) π/4 (i=1,2 ... 5).Fig. 3 hollow core arrow is a cylindrical permanent magnet internal magnetic field direction.On the direction, the direction of magnetization of the magnetic patch in same group changes according to β ()=2 .The external radius of semisphere permanent magnet equates that with the external radius of cylindrical permanent magnet the internal diameter of semisphere permanent magnet obtains according to (14) formula, to guarantee under the condition of minimum leakage field the uniformity of magnetic field in the test tube shaped magnet.
Semisphere permanent magnet shown in Figure 3 is superimposed upon on the end face of cylindrical permanent magnet shown in Figure 2, makes two magnets magnetic direction unanimity on the axis in cylindrical cavity, constitute test tube shaped magnet as shown in Figure 1.
The good effect of the specific embodiment of the invention is as follows:
1, the uniform magnetic field region of test tube shape magnet of the present invention to hemispherical magnet direction depart from cylindrical magnet in The heart, when the NMR instrument that uses test tube shape magnet is measured sample in the test tube, the shape of magnet and test tube Shape conform to, uniform magnetic field region is position, space and the space of specimen in test tube in test tube shape magnet The position is consistent, and magnet structure is more reasonable, has therefore significantly improved the magnetic field space utilization rate, thereby effectively Reduce magnet size, alleviate magnet weight.
2, during the actual design of test tube shape magnet of the present invention, improve on the cross section by increasing circumferential magnetic patch number The transverse magnetic field uniformity. The magnetic field interaction of hemispherical and cylindrical two kinds of magnets, at test tube shape magnet In the hollow cavity, each magnetic-field component obtains effectively compensation, overcomes Chinese patent 200510011970.2 and " uses Permanent magnet in portable nuclear magnetic resonance instrument " in system's mistake of existing when adopting half-cylindrical permanent magnet compensation Difference, thus the uniformity in axially upper horizontal magnetic field improved, relatively reduced the volume of magnet, alleviated instrument Weight.
3, test tube shape magnet of the present invention cylindrical magnet circumferentially, and the outside leakage field of hemispherical magnet is very Little, so magnetic energy utilization rate height, it is few to obtain the required permanent magnetism material of same magnetic field intensity.
4, the design of test tube shape magnet of the present invention need not ferromagnetic material and consists of the closed-loop path and improve cavity Uniformity of magnetic field in the body, it is huge and heavy to have overcome the polar-plate-type magnet, is unfavorable for the shortcoming of carrying, greatly Minimizing the consumption of ferromagnetic material, alleviated the weight of magnet.
Above-mentioned good effect of the present invention has demonstrated fully novel test tube shape magnet at portable NMR instrument In application advantage.
Claims (5)
1, a kind of permanent magnet that is used for portable nuclear magnetic resonance instrument magnetostatic field generator, it is characterized in that being made of the cylindrical permanent magnet of a hollow and the semisphere permanent magnet of a hollow, the shaft section of semisphere permanent magnet is superimposed upon on the end face of cylindrical permanent magnet; The cylindrical permanent magnet of hollow is made of by the seccotine adhesion the identical fan-shaped permanent magnet of shape, is divided into N=2M (M is the integer greater than 2) piece along the cylindrical permanent magnet circumferencial direction, and each magnetic patch shaft section is fan-shaped; The semisphere permanent magnet is the external diameter that equals cylindrical permanent magnet with external diameter, internal diameter is less than the internal diameter of cylindrical permanent magnet, axle is parallel to the semicircular ring of magnetic direction, obtain around the axle rotation that is parallel to magnetic direction, the semisphere permanent magnet is positioned at the end of the outside closed circular cylindrical magnet of hollow type cylindrical magnet; The semisphere permanent magnet is consistent with cylindrical permanent magnet transverse magnetic field direction on the axis in cylindrical cavity, and the whole magnet after the combination constitutes test tube shaped; In the cavity of test tube shaped is uniform magnetic field.
2, according to the described permanent magnet that is used for portable nuclear magnetic resonance instrument magnetostatic field generator of claim 1, each the magnetic patch shape of cylindrical permanent magnet that it is characterized in that forming hollow is identical, magnetic field intensity equates that direction of magnetization is the twice of the sense of rotation of magnetic patch own.
3, according to the described permanent magnet that is used for portable nuclear magnetic resonance instrument magnetostatic field generator of claim 1, it is characterized in that, at spheric coordinate system (r, , θ), form respectively organizing in the magnetic patch of semisphere permanent magnet, each magnetic patch in every group of magnet, on the θ direction, has identical α (θ)=θ direction of magnetization; The direction of magnetization of the magnetic patch in same group on the direction, changes according to β ()=2 .
4,, it is characterized in that the interior external radius of semisphere permanent magnet and the interior external radius of cylindrical permanent magnet satisfy according to the described permanent magnet that is applicable to portable nuclear magnetic resonance instrument magnetostatic field generator of claim 1:
5, according to the described permanent magnet that is applicable to portable nuclear magnetic resonance instrument magnetostatic field generator of claim 1, it is characterized in that, when end face stack of the shaft section of semisphere permanent magnet and cylindrical permanent magnet, the center of circle of an end face of cylindrical permanent magnet should be concentric with the center of circle of the shaft section of semisphere permanent magnet.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2005100864071A CN100568017C (en) | 2005-09-13 | 2005-09-13 | A kind of permanent magnet that is used for portable nuclear magnetic resonance instrument magnetostatic field generator |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2005100864071A CN100568017C (en) | 2005-09-13 | 2005-09-13 | A kind of permanent magnet that is used for portable nuclear magnetic resonance instrument magnetostatic field generator |
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| Publication Number | Publication Date |
|---|---|
| CN1932545A true CN1932545A (en) | 2007-03-21 |
| CN100568017C CN100568017C (en) | 2009-12-09 |
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ID=37878477
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB2005100864071A Expired - Fee Related CN100568017C (en) | 2005-09-13 | 2005-09-13 | A kind of permanent magnet that is used for portable nuclear magnetic resonance instrument magnetostatic field generator |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102426897A (en) * | 2011-12-20 | 2012-04-25 | 重庆大学 | Semi-elliptical-distributed open nuclear magnetic resonance permanent structure |
| CN105201498A (en) * | 2015-09-23 | 2015-12-30 | 中国石油大学(北京) | Nuclear magnetic resonance downhole fluid analyzer |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4835506A (en) * | 1988-05-27 | 1989-05-30 | The United States Of America As Represented By The Secretary Of The Army | Hollow substantially hemispherical permanent magnet high-field flux source |
| CN1401295A (en) * | 2001-08-29 | 2003-03-12 | 中国科学院武汉物理与数学研究所 | Permanent magnet for nuclear magnetic resonance image-forming apparatus |
| CN2694444Y (en) * | 2004-04-05 | 2005-04-20 | 北京大学 | Permanent magnet acceptable for portable nuclear magnetic resonance apparatus |
-
2005
- 2005-09-13 CN CNB2005100864071A patent/CN100568017C/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102426897A (en) * | 2011-12-20 | 2012-04-25 | 重庆大学 | Semi-elliptical-distributed open nuclear magnetic resonance permanent structure |
| CN105201498A (en) * | 2015-09-23 | 2015-12-30 | 中国石油大学(北京) | Nuclear magnetic resonance downhole fluid analyzer |
| CN105201498B (en) * | 2015-09-23 | 2018-03-09 | 中国石油大学(北京) | Nuclear magnetic resonance downhole fluid analysis instrument |
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| Publication number | Publication date |
|---|---|
| CN100568017C (en) | 2009-12-09 |
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