阅读说明：本技术 一种静态磁场控制方法和磁共振成像装置 (Static magnetic field control method and magnetic resonance imaging device ) 是由 徐春明 毛青 于 2019-10-15 设计创作，主要内容包括：本发明涉及磁共振成像技术领域,且公开了一种磁共振成像装置,包括磁共振主体、主磁场装置、射频线圈、接收装置及移动床,磁共振主体内部设置滑动主体,滑动主体左侧壁面与磁共振主体内部左侧壁面固定连接,磁共振主体内部上下侧面分别固定安装主磁场装置,磁共振主体内部设置两个补偿线圈,本发明,通过在移动床上固定安装电磁层和设置有拉力柱,磁共振装置开启,补偿线圈产生磁力,吸引电磁层靠近从而带动移动床向磁共振装置主体内部移动将患者带入检测装置中,避免了使用电机等电气设备带动患者移动,解决了使用电气设备时电流通过会产生微弱的电磁场,可能会影响到磁共振装置中的静态磁场,使磁共振成像装置扫描出的图像有误差的问题。(The invention relates to the technical field of magnetic resonance imaging, and discloses a magnetic resonance imaging device, which comprises a magnetic resonance main body, a main magnetic field device, a radio frequency coil, a receiving device and a moving bed, wherein a sliding main body is arranged in the magnetic resonance main body, the left side wall surface of the sliding main body is fixedly connected with the left side wall surface in the magnetic resonance main body, the main magnetic field device is fixedly arranged on the upper side surface and the lower side surface in the magnetic resonance main body respectively, and two compensating coils are arranged in the magnetic resonance main body. The static magnetic field in the magnetic resonance imaging apparatus may be affected, which may cause an error in the image scanned by the magnetic resonance imaging apparatus.)

1. A magnetic resonance imaging device comprises a magnetic resonance main body (1), a main magnetic field device (3), a radio frequency coil (4), a receiving device (7) and a moving bed (13), and is characterized in that: the magnetic resonance imaging device is characterized in that the magnetic resonance main body (1) is a hollow cylinder, a detection inlet (8) is formed in the right side wall surface of the magnetic resonance main body (1), a sliding main body (11) is arranged in the magnetic resonance main body (1), the sliding main body (11) is a cuboid, the left side wall surface of the sliding main body (11) is fixedly connected with the left side wall surface in the magnetic resonance main body (1), the right end of the sliding main body (11) extends out of the magnetic resonance main body (1) through the detection inlet (8), the upper side surface and the lower side surface in the magnetic resonance main body (1) are respectively and fixedly provided with a main magnetic field device (3), a radio frequency coil (4) is arranged in the magnetic resonance main body (1), a receiving coil (5) is arranged in the magnetic resonance main body (1), a receiving device (7) is;

two chutes (12) are formed in the wall face above the sliding main body (11), the two chutes (12) correspond to each other from front to back, a moving bed (13) is arranged above the sliding main body (11), four fixing columns (14) are fixedly installed on the wall face below the moving bed (13), rollers (15) are movably installed below the four fixing columns (14) respectively, the four rollers (15) are movably clamped on the inner sides of the two chutes (12) respectively, electromagnetic layers (17) are fixedly installed on the front and back left side faces of the moving bed (13), tension columns (16) are fixedly installed on the front and back right side wall faces of the two fixing columns (14) respectively on the right side, the two tension columns (16) are located on the inner sides of the front and back chutes (12) respectively, and the right side wall faces of the two tension columns (16).

2. A magnetic resonance imaging apparatus according to claim 1, characterized in that: the magnetic resonance device is characterized in that the compensation coils (6) are circular ring-shaped electromagnetic coils, the two compensation coils (6) correspond to each other left and right, the two compensation coils (6) are positioned between the upper main magnetic field device and the lower main magnetic field device (3), the sliding main body (11) is positioned on the inner sides of the two compensation coils (6), and the side surfaces of the compensation coils (6) are fixedly connected with the front wall surface and the rear wall surface of the inner side of the magnetic resonance main body (1) respectively.

3. A magnetic resonance imaging apparatus according to claim 1, characterized in that: the magnetic resonance device is characterized in that a wire passing pipe (9) is fixedly installed inside the magnetic resonance main body (1), the outer rear wall surface of the wire passing pipe (9) is fixedly connected with the inner rear wall surface of the magnetic resonance main body (1), and a right side port of the wire passing pipe (9) penetrates through the left side wall surface of the magnetic resonance main body (1).

4. A magnetic resonance imaging apparatus according to claim 1, characterized in that: the wall surface below the sliding main body (11) is fixedly provided with a support leg (18), the support leg (18) is a cuboid, and the support leg (18) is positioned on the right side of the magnetic resonance main body (1).

5. A magnetic resonance imaging apparatus according to claim 1, characterized in that: the cooling water pipe (2) is fixedly installed inside the side face and the left side wall face of the magnetic resonance main body (1), the water inlet pipe (10) is fixedly installed on the left side wall face of the magnetic resonance main body (1), and the water inlet pipe (10) is communicated with the cooling water pipe (2).

6. A static magnetic field control method comprising: s1: arranging an electromagnetic coil;

s2: energizing the electromagnetic coil;

s3: adjusting the magnetic field intensity;

s4: a static magnetic field is formed.

7. The static magnetic field control method according to claim 7, wherein: the step of arranging the electromagnetic coil in the step S1 specifically comprises the following steps: two corresponding electromagnetic coils are arranged, and the electromagnetic coil is formed by winding a conducting wire.

8. The static magnetic field control method according to claim 7, wherein: the S2 electromagnetic coil is electrified specifically by the following steps: and (3) introducing currents in the same direction into the two electromagnetic coils to enable the two electric measuring coils to respectively generate magnetic fields, determining the direction of the required magnetic field by a right-hand spiral theorem to determine the current introduction direction of the electromagnetic coils, wherein the directions of the magnetic fields generated by the two electromagnetic coils are the same.

9. The static magnetic field control method according to claim 7, wherein: the S3 specifically comprises the following steps of: and adjusting the current passing through the two electromagnetic coils by using a computer and a current control device to ensure that the magnetic field intensity generated by the two electromagnetic coils reaches the intensity required by magnetic resonance, and calculating the magnetic field intensity by using the Boit-Savart law and the current intensity.

10. The static magnetic field control method according to claim 7, wherein: the step of forming the static magnetic field by the step of S4 is as follows: when the magnetic field intensity generated by the two electromagnetic coils is adjusted to be the same, the magnetic field lines generated by the two electromagnetic coils are overlapped, and the space between the two electromagnetic coils is distributed with a highly uniform magnetic field to form a controllable static magnetic field.

Technical Field

The invention relates to the technical field of magnetic resonance imaging, in particular to a static magnetic field control method and a magnetic resonance imaging device.

Background

Nuclear magnetic resonance imaging, also known as spin imaging and magnetic resonance imaging, taiwan is also known as magnetic resonance imaging, and hong kong is also known as magnetic resonance imaging, which utilizes the principle of nuclear magnetic resonance, detects emitted electromagnetic waves through an external gradient magnetic field according to different attenuations of released energy in different structural environments inside a substance, so as to obtain the positions and the types of atomic nuclei forming the substance, and accordingly, the nuclear magnetic resonance imaging can be drawn into structural images inside the substance, and the technology is used for imaging the internal structure of a human body, so that a revolutionary medical diagnostic tool is generated. The application of the rapidly changing gradient magnetic field greatly accelerates the speed of nuclear magnetic resonance imaging, realizes the application of the technology in clinical diagnosis and scientific research, and greatly promotes the rapid development of medicine, neurophysiology and cognitive neuroscience. At present, when the magnetic resonance imaging device is used, a patient can be driven to enter a moving bed in the detection device by the aid of a motor, the magnetic resonance imaging device can generate a high-intensity magnetic field when the magnetic resonance imaging device is used, electrical equipment such as the motor is easy to magnetize in the high-intensity magnetic field and is influenced by the magnetic field, so that the motor needs to be frequently detected and maintained, meanwhile, the current of the electrical equipment such as the motor can generate a weak electromagnetic field, a static magnetic field in the magnetic resonance imaging device can be influenced, and an image scanned by the magnetic resonance imaging device has errors.

Disclosure of Invention

Technical problem to be solved

Aiming at the defects of the prior art, the invention provides a static magnetic field control method and a magnetic resonance imaging device, which have the advantages of not using any electrical equipment and the like, and solve the problem that when the electrical equipment is used, the static magnetic field in the magnetic resonance imaging device is possibly influenced by a weak electromagnetic field generated by the passing of current, so that the scanned image of the magnetic resonance imaging device has errors.

(II) technical scheme

In order to achieve the purpose of not using any electrical equipment, the invention provides the following technical scheme: a magnetic resonance imaging device comprises a magnetic resonance main body, a main magnetic field device, a radio frequency coil, a receiving device and a moving bed, wherein the magnetic resonance main body is a hollow cylinder, a detection inlet is formed in the right side wall surface of the magnetic resonance main body, a sliding main body is arranged in the magnetic resonance main body, the sliding main body is a cuboid, the left side wall surface of the sliding main body is fixedly connected with the left side wall surface in the magnetic resonance main body, the right end of the sliding main body extends out of the magnetic resonance main body through the detection inlet, the main magnetic field device is fixedly installed on the upper side surface and the lower side surface in the magnetic resonance main body respectively, the radio frequency coil is arranged in the magnetic resonance device, the front wall surface and the rear wall surface of the radio frequency coil are fixedly connected with the inner side surface of the magnetic resonance main body respectively, the radio, the compensating coils are circular ring type electromagnetic coils, the two compensating coils correspond to each other left and right, the two compensating coils are positioned between the upper main magnetic field device and the lower main magnetic field device, the sliding main body is positioned inside the two compensating coils, the side surfaces of the compensating coils are fixedly connected with the front wall surface and the rear wall surface of the inner side of the magnetic resonance main body respectively, the wire passing pipe is fixedly installed inside the magnetic resonance main body, the rear wall surface outside the wire passing pipe is fixedly connected with the rear wall surface inside the magnetic resonance main body, and the right end port of the wire passing;

the magnetic resonance device comprises a sliding main body, wherein the upper wall surface of the sliding main body is provided with two sliding grooves, the sliding grooves are rectangular grooves, the two sliding grooves correspond to each other in the front and the back, a moving bed is arranged above the sliding main body, the lower wall surface of the moving bed is fixedly provided with four fixed columns, the lower parts of the four fixed columns are respectively and movably provided with a roller, the four rollers are respectively and movably clamped at the inner sides of the two sliding grooves, the front and the back left side surfaces of the moving bed are respectively and fixedly provided with an electromagnetic layer, the right side walls of the front and the back fixed columns on the right side are respectively and fixedly provided with a tension column, the two tension columns are respectively positioned at the inner;

and cooling water pipes are fixedly arranged in the side surface and the left side wall surface of the magnetic resonance main body, a water inlet pipe is fixedly arranged on the left side wall surface of the magnetic resonance main body, and the water inlet pipe is communicated with the cooling water pipes.

A static magnetic field control method comprising: s1: arranging electromagnetic coils, wherein the two corresponding electromagnetic coils are arranged, and the electromagnetic coil is formed by winding a conducting wire;

s2: the electromagnetic coils are electrified, currents in the same direction are led into the two electromagnetic coils, the two electric measuring coils are enabled to generate magnetic fields respectively, the current leading-in direction of the electromagnetic coils is determined by determining the required magnetic field direction through the right-hand spiral theorem, and the directions of the magnetic fields generated by the two electromagnetic coils are the same;

s4: adjusting the magnetic field intensity, adjusting the current passing through the two electromagnetic coils by using a computer and current control equipment to ensure that the magnetic field intensity generated by the two electromagnetic coils reaches the intensity required by magnetic resonance, and calculating the magnetic field intensity by using the Boit-Savart law and the current intensity;

s5: and a static magnetic field is formed, the magnetic field intensity generated by the two electromagnetic coils is adjusted to be the same, the magnetic field lines generated by the two electromagnetic coils are overlapped, and the space between the two electromagnetic coils is distributed with a highly uniform magnetic field to form a controllable static magnetic field.

Preferably, the magnetic resonance main body is made of nonmagnetic plastic with high hardness, and the magnetic resonance main body is not influenced by a magnetic field.

Preferably, the main magnetic field device is a hollow box, the electromagnetic coil is fixedly mounted in the main magnetic field device, the upper and lower main magnetic field devices generate magnetic fields by connecting current, the directions of the magnetic fields generated by the upper and lower main magnetic field devices are the same, a static magnetic field is formed between the two main magnetic fields, the static magnetic field between the two main magnetic field devices maintains a magnetic field strength with uniform height, and the magnetic field strength between the two main magnetic field devices is controlled and adjusted by the strength of current applied to the two main magnetic field devices.

Preferably, the radio frequency coil is used for radiating radio frequency electromagnetic waves with specified frequency and certain power to a human body so as to excite the resonance of an atomic nucleus of the exciter, and the radio frequency coil is an existing structure and is not described herein again.

Preferably, the receiving coil transmits the received weak attenuation signal to the receiving device through a lead, and the receiving device amplifies the received signal and transmits the amplified signal to a computer to process and generate an image so as to observe the physical condition of the patient.

Preferably, the compensation coil is used for compensating the main magnetic field coil, so that the static magnetic field generated by the compensation coil is close to an ideal uniform magnetic field, and the compensation coil needs computer-aided work due to high precision requirement and extremely complex calibration work, and needs to be measured, calculated and corrected for many times to meet the requirement.

Preferably, the wire conduit is a pipe made of a material capable of shielding a magnetic field.

Preferably, the electromagnetic layer is a layer of magnetic iron sheet, so that when the magnetic resonance device is started, the compensation coil generates magnetic force to attract the electromagnetic layer to approach so as to drive the moving bed to move towards the inside of the magnetic resonance device main body.

Preferably, the tension column is a cylinder with elasticity.

(III) advantageous effects

Compared with the prior art, the invention provides a static magnetic field control method and a magnetic resonance imaging device, which have the following beneficial effects:

1. the static magnetic field control method and the magnetic resonance imaging device are characterized in that an electromagnetic layer and a tension column are fixedly arranged on a movable bed, the magnetic resonance device starts a compensation coil and the electromagnetic layer to generate magnetic force to attract the electromagnetic layer to approach so as to drive the movable bed to move towards the inside of a magnetic resonance device main body, when the movable bed is positioned at the inner side of the device main body, the magnetic field generated by the electromagnetic layer and the compensation coil compensate a main magnetic field, after a patient is examined, the magnetic resonance device is closed, the magnetism carried by the compensation coil and the electromagnetic layer disappears slowly, the suction force to the electromagnetic layer disappears slowly, the movable bed is pulled by the two tension columns to move out of the magnetic resonance device main body slowly, the examined patient leaves away, the condition that the patient is driven to move by using electric equipment such as a motor is avoided, the problem that a weak electromagnetic field is generated by current when the electric equipment is used is solved, and the static magnetic field in the, the problem of errors in the images scanned by the magnetic resonance imaging device.

2. According to the static magnetic field control method and the magnetic resonance imaging device, the wire passing pipe capable of shielding the magnetic field is fixedly arranged in the magnetic resonance main body, various wires in the magnetic resonance main body are wired through the wire passing pipe, and the problem that the magnetic resonance imaging is inaccurate due to the fact that the stability of a main magnetic field is influenced by current in the wires in use is avoided.

3. According to the static magnetic field control method and the magnetic resonance imaging device, the two electromagnetic coils are used as the main magnetic field generating device, the static magnetic field is controlled through the static magnetic field control method, the strength of the static magnetic field is easier to adjust, the problem that the static magnetic field is difficult to adjust and control due to the fact that two permanent magnets are used for magnetizing is avoided, and the method is simple to use as long as the current is adjusted when the magnetic resonance device works.

Drawings

Figure 1 is a front view of a magnetic resonance imaging apparatus;

fig. 2 is a front sectional view of the magnetic resonance imaging apparatus.

In the figure: the device comprises a magnetic resonance main body 1, a cooling water pipe 2, a main magnetic field device 3, a radio frequency coil 4, a receiving coil 5, a compensating coil 6, a receiving device 7, a detection inlet 8, a line passing pipe 9, a water inlet pipe 10, a sliding main body 11, a sliding chute 12, a moving bed 13, a fixed column 14, a roller 15, a tension column 16, an electromagnetic layer 17 and a supporting leg 18.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1-2, a magnetic resonance imaging apparatus includes a magnetic resonance main body 1, a main magnetic field device 3, a radio frequency coil 4, a receiving device 7, and a moving bed 13, wherein the magnetic resonance main body 1 is a hollow cylinder, the magnetic resonance main body 1 is made of nonmagnetic plastic with high hardness, the magnetic resonance main body 1 is not affected by a magnetic field, a detection inlet 8 is formed on a right side wall surface of the magnetic resonance main body 1, a patient enters the magnetic resonance main body 1 through the detection inlet 8 to perform magnetic resonance examination, a sliding main body 11 is arranged inside the magnetic resonance main body 1, the sliding main body 11 is a cuboid, a left side wall surface of the sliding main body 11 is fixedly connected with a left side wall surface inside the magnetic resonance main body 1, a right end of the sliding main body 11 extends out of the magnetic resonance main body 1 through the detection inlet 8, the main magnetic field device 3 is fixedly installed on upper and lower sides, an electromagnetic coil is fixedly arranged in the main magnetic field devices 3, the upper and lower main magnetic field devices 3 generate magnetic fields by accessing current, the directions of the magnetic fields generated by the upper and lower main magnetic field devices 3 are the same, a static magnetic field is formed between the two main magnetic fields, the static magnetic field between the two main magnetic field devices 3 keeps the magnetic field strength with uniform height, the magnetic field strength between the two main magnetic field devices 3 is controlled and adjusted by the current strength applied to the two main magnetic field devices 3, a radio frequency coil 4 is arranged in the magnetic resonance device, the radio frequency coil 4 is used for radiating radio frequency electromagnetic waves with specified frequency and certain power to a human body and is used for exciting the resonance of atomic nuclei of an apparatus, the radio frequency coil 4 is the prior structure and is not repeated herein, the front wall surface and the rear wall surface of the radio frequency coil 4 are respectively and fixedly connected, the inner side of the magnetic resonance main body 1 is provided with a receiving coil 5, the receiving coil 5 is used for receiving free induction attenuation signals reflected by a human body, the wall surface below the sliding main body 11 is fixedly provided with a receiving device 7, the receiving coil 5 transmits the received weak attenuation signals to the receiving device 7 through a lead, the receiving device 7 amplifies the received signals and transmits the amplified signals to a computer to process and generate images so as to observe the physical condition of a patient, two compensating coils 6 are arranged in the magnetic resonance main body, the compensating coils 6 are circular ring type electromagnetic coils, the two compensating coils 6 correspond to each other left and right, the two compensating coils 6 are positioned between an upper main magnetic field device and a lower main magnetic field device 3, the sliding main body 11 is positioned at the inner sides of the two compensating coils 6, the side surfaces of the compensating coils 6 are respectively and fixedly connected with the front and rear wall surfaces of the, the static magnetic field generated by the magnetic resonance imaging compensation coil 6 is close to an ideal uniform magnetic field, the compensation coil 6 is extremely complicated in calibration due to high precision requirement, computer-aided work is needed, multiple measurement, multiple calculation and correction are needed to meet the requirement, a wire passing pipe 9 is fixedly installed in the magnetic resonance main body 1, the wire passing pipe 9 is a pipeline made of a material capable of shielding the magnetic field, the rear wall surface outside the wire passing pipe 9 is fixedly connected with the rear wall surface inside the magnetic resonance main body 1, a right side port of the wire passing pipe 9 penetrates through the left side wall surface of the magnetic resonance main body 1, various wires in the magnetic resonance main body 1 are wired through the wire passing pipe 9, and the problem that the magnetic resonance imaging is inaccurate due to the fact that the stability of a main magnetic field is influenced;

the upper wall surface of the sliding main body 11 is provided with two sliding grooves 12, the sliding grooves 12 are rectangular grooves, the two sliding grooves 12 correspond to each other in front and back, a moving bed 13 is arranged above the sliding main body 11, the moving bed 13 is a cuboid, the moving bed 13 is made of demagnetized plastics, the lower wall surface of the moving bed 13 is fixedly provided with four fixing columns 14, the fixing columns 14 are cuboids with square frames fixedly arranged below the fixing columns 14, rollers 15 are respectively and movably arranged below the four fixing columns 14, the four rollers 15 are respectively and movably clamped at the inner sides of the two sliding grooves 12, the moving bed 13 can send a patient lying on the moving bed 13 into the magnetic resonance main body 1 for detection through the movement of the four rollers 15 in the sliding grooves 12, the front side surface and the back side surface of the moving bed 13 are respectively and fixedly provided with an electromagnetic layer 17, the electromagnetic layer 17 is a layer which can generate magnetism when the patient, the electromagnetic layer 17 is attracted to approach to drive the moving bed 13 to move towards the inside of the magnetic resonance device body, when the moving bed 13 is positioned at the inner side of the device body, the magnetic field generated by the electromagnetic layer 17 and the compensation coil 6 compensate the main magnetic field together, the right side wall surfaces of the front and rear right fixing columns 14 on the right side are respectively and fixedly provided with a tension column 16, the tension column 16 is a cylinder with elasticity, the two tension columns 16 are respectively positioned at the inner sides of the front and rear sliding grooves 12, the right side wall surfaces of the two tension columns 16 are respectively and fixedly connected with the right side wall surfaces inside the two sliding grooves 12, after the examination of a patient is completed, the magnetic resonance device is closed, the magnetism carried by the compensation coil 6 slowly disappears, the attraction force to the electromagnetic layer 17 slowly disappears, the moving bed 13 slowly moves out of the magnetic resonance device body under the pulling of the two tension columns 16 to allow the examined, the support leg 18 is a cuboid, and the support leg 18 is positioned at the right side of the magnetic resonance main body 1;

inside fixed mounting condenser tube 2 of 1 side of magnetic resonance main part and left side wall, 1 left side wall fixed mounting inlet tube 10 of magnetic resonance main part, and inlet tube 10 and condenser tube 2 intercommunication, inject a large amount of water into condenser tube 2 through inlet tube 10 before magnetic resonance dress uses, main magnetic field device 3 can produce a large amount of heats through the electric current when magnetic resonance device uses, can make the inboard high temperature of magnetic resonance main part 1 if not cooling down, influence whole magnetic resonance imaging device's life.

When the device is used, a large amount of water is injected into the cooling water pipe 2 through the water inlet pipe 10 before the magnetic resonance device is used, the magnetic resonance device starts the compensation coil 6 and the electromagnetic layer 17 to generate magnetic force, the electromagnetic layer 17 is attracted to be close to drive the moving bed 13 to move towards the inside of the magnetic resonance device main body, when the moving bed 13 is positioned at the inner side of the device main body, the magnetic field generated by the electromagnetic layer 17 and the compensation coil 6 compensate the main magnetic field, the two main magnetic field devices 3 generate magnetic fields through connecting current, a static magnetic field is formed between the two main magnetic fields, the static magnetic field between the two main magnetic field devices 3 keeps highly uniform magnetic field intensity, the compensation coil 6 generates the magnetic field compensation main magnetic field device 3 to enable the static magnetic field generated by the main magnetic field device 3 to approach to an ideal uniform magnetic field, the radio frequency coil 4 is used for radiating radio frequency, the receiving coil 5 transmits the received weak attenuation signals to the receiving device 7 through a lead, and the receiving device 7 amplifies the received signals and transmits the amplified signals to a computer to process and generate images so as to observe the physical condition of the patient.

A static magnetic field control method comprising: s1: arranging electromagnetic coils, wherein the two corresponding electromagnetic coils are arranged, and the electromagnetic coil is formed by winding a conducting wire;

s2: the electromagnetic coils are electrified, currents in the same direction are led into the two electromagnetic coils, the two electric measuring coils are enabled to generate magnetic fields respectively, the current leading-in direction of the electromagnetic coils is determined by determining the required magnetic field direction through the right-hand spiral theorem, and the directions of the magnetic fields generated by the two electromagnetic coils are the same;

s4: adjusting the magnetic field intensity, adjusting the current passing through the two electromagnetic coils by using a computer and current control equipment to ensure that the magnetic field intensity generated by the two electromagnetic coils reaches the intensity required by magnetic resonance, and calculating the magnetic field intensity by using the Boit-Savart law and the current intensity;

s5: and a static magnetic field is formed, the magnetic field intensity generated by the two electromagnetic coils is adjusted to be the same, the magnetic field lines generated by the two electromagnetic coils are overlapped, and the space between the two electromagnetic coils is distributed with a highly uniform magnetic field to form a controllable static magnetic field.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.