Controllable magnetic field generating device

Abstract

The invention relates to the field of biomedical research, and discloses a controllable magnetic field generation device which comprises a magnetic field generation device and a heat effect comparison device which are separated through a heat insulation plate. The magnetic field generation device and the heat effect comparison device comprise a magnetic field control table and a Helmholtz coil group mounted above the magnetic field control table; a transverse guide rod penetrates through the center of the movable base on the left side and the right side above the magnetic field control table, symmetrical transverse screws are arranged on the surfaces of the two ends of the transverse guide rod, the transverse screws are screwed to the center of the movable base through threads, and an adjusting rotary handle is fixedly connected to the end of the transverse guide rod. Compared with the prior art, the device has the advantages of concentrated and stable magnetic field intensity, convenience in magnetic field type regulation and control, weak heat effect and the like, and solves a series of problems of poor magnetic field uniformity, inconvenience in magnetic field type regulation and control, great influence of heat effect on experiments and the like.

Description

Technical Field

[0001] This invention relates to the field of biomedical research, specifically to a controllable magnetic field generating device. Background Technology

[0002] In the field of biomedical research, the effects of magnetic fields on cellular physiological activities (such as cell proliferation, differentiation, apoptosis, and signal transduction) are an important research direction. To explore the biological effects of different types of magnetic fields (constant magnetic fields, alternating magnetic fields, pulsed magnetic fields, etc.), it is necessary to rely on precise and controllable magnetic field generating devices to adjust magnetic field parameters (intensity, frequency, exposure time, etc.) and ensure that cell samples are in a stable culture environment (37°C, 5% CO2, etc.).

[0003] Currently, most magnetic field generating devices used in cell experiments employ Helmholtz coils as the core of the magnetic field, as they can generate a highly uniform magnetic field in the central region, making them suitable for the simultaneous exposure of batches of samples. However, existing devices have the following shortcomings in practical applications: ① The size of the uniform magnetic field region of the Helmholtz coil is closely related to the coil spacing (the uniform region is largest when the standard spacing is the coil radius). However, in experiments, the magnetic field strength or frequency needs to be adjusted according to research requirements (such as increasing the current to increase the strength). At this time, the coil generates more heat, and the coil spacing needs to be increased to reduce the thermal effect. However, changes in coil spacing will cause the uniform magnetic field region to shrink. The cell culture dish placement structure of the existing device is fixed and cannot shrink synchronously to match the new uniform region, resulting in some samples being in a non-uniform magnetic field, affecting the reliability of experimental data. ② After the coil is energized, it generates heat due to the Joule effect. Its temperature rises significantly with the increase of current intensity and frequency, and it is easy to deviate from the 37°C constant temperature environment required for cell culture. ③ In research, it is necessary to switch between different types of magnetic fields such as constant, alternating, and pulsed. However, the power system of the existing device has poor compatibility with the coil structure. When switching, hardware needs to be replaced or recalibrated, which is cumbersome. Moreover, the control precision of magnetic field parameters (such as pulse width and alternating frequency) is insufficient, which easily leads to waveform distortion or intensity fluctuations, affecting the reproducibility of experiments.

[0004] Therefore, based on the above problems, the present invention provides a controllable magnetic field generating device. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a controllable magnetic field generator with advantages such as concentrated and stable magnetic field strength, convenient magnetic field type control, and weak thermal effect. It solves a series of problems such as poor magnetic field uniformity, inconvenient magnetic field type control, and significant impact of thermal effect on experiments.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a controllable magnetic field generating device, comprising a magnetic field generating device and a thermal effect comparison device, wherein the magnetic field generating device and the thermal effect comparison device are separated by a heat insulation plate, and the magnetic field generating device and the thermal effect comparison device include a magnetic field control console and a Helmholtz coil assembly installed above the magnetic field control console;

[0007] The Helmholtz coil assembly includes a winding core, with coils wound around the outer surface of the winding core. There are two sets of winding cores, which are symmetrically arranged on the left and right sides above the magnetic field control console. The axes of the two sets of winding cores coincide and are parallel. A cross is fixedly installed on the inner wall of the winding core. Mounting brackets are fixedly connected to the center of the cross on both sides. A movable base is fixedly connected to the lower end of the mounting brackets on both sides. Slide rails are installed on the front and back of the upper end of the magnetic field control console. The movable base is slidably installed on the slide rails on the front and back sides.

[0008] A horizontal guide rod is inserted through the center of the movable base on the left and right sides above the magnetic field control console. Symmetrical horizontal spirals are provided on the two ends of the horizontal guide rod. The horizontal spirals are screwed into the center of the movable base. An adjustment handle is fixedly connected to the end of the horizontal guide rod.

[0009] A petri dish placement assembly is installed above the center of the magnetic field control console to hold the petri dishes. The petri dish placement assembly is located at the center of the Helmholtz coil assembly.

[0010] Preferably, the upper end of the magnetic field control console is provided with a scale.

[0011] Preferably, the petri dish placement assembly includes a petri dish placement rack fixed to the middle of the upper end of the magnetic field control console. A driven rod is rotatably mounted on the top of the petri dish placement rack. A driven bevel gear is fixedly connected to the lower end of the driven rod. An active bevel gear is fixedly fitted onto the middle outer surface of the transverse guide rod. The active bevel gear and the driven bevel gear mesh. Several petri dish placement plates are vertically distributed inside the petri dish placement rack. The driven rod vertically inserts into the center of the petri dish placement plate. Several vertical spirals are provided on the outer surface of the driven rod. The vertical spirals are screwed into the center of the petri dish placement plate. Petri dish placement grooves are provided on the left and right sides of the upper end face of the petri dish placement plate.

[0012] Preferably, a back plate is fixedly provided on the front side wall of the petri dish placement rack, a filter screen is installed on the back plate, and a cooling fan is installed on the back plate where the filter screen is located.

[0013] Preferably, a transparent glass door is rotatably mounted on the rear side wall of the back panel.

[0014] Preferably, a heat exchange assembly is installed at the bottom of several culture dish placement plates in the culture dish placement rack. The heat exchange assembly includes heat exchange coils embedded in the bottom of the culture dish placement plates. The heat exchange coils on the same side of the bottom of adjacent culture dish placement plates are connected by corrugated pipes. The heat exchange coils on the same side of the bottom of the upper and lower culture dish placement plates are respectively connected to one end of the liquid outlet hose and the liquid inlet hose. The other end of the liquid inlet hose is connected to the upper end of the mounting rack, and the other end of the liquid outlet hose is connected to the circulation pump installed on the mounting rack.

[0015] Preferably, the petri dish rack and its internal petri dish placement plate are made of PET plastic, and the heat exchange coil is made of copper tubing.

[0016] Preferably, the interior of the winding core is hollow, the interior of the cross is hollow and connected to the interior of the winding core, the upper end of the mounting bracket is hollow, and the hollow is an interconnected cavity.

[0017] Compared with the prior art, the present invention provides a controllable magnetic field generating device, which has the following beneficial effects:

[0018] 1. This controllable magnetic field generator, through a transverse guide rod, adjusting handle, and screw drive structure, allows for precise adjustment of the spacing of the Helmholtz coil assembly to adapt to different magnetic field strength requirements. Simultaneously, the meshing transmission of the active and driven bevel gears causes the culture dish placement plate to synchronously contract or expand with the coil spacing, ensuring that all culture dishes are always within a uniform magnetic field region (uniformity deviation ≤5%). This solves the problem in existing devices where some samples are exposed to a non-uniform magnetic field after changes in coil spacing, ensuring the consistency of experimental conditions for batch samples and significantly improving data reliability.

[0019] 2. This controllable magnetic field generating device comprises a closed-loop heat exchange system consisting of a hollow winding iron core, a cross-shaped structure, and heat exchange components. It utilizes coil heat to heat the heat exchange fluid (kerosene), and achieves closed-loop temperature control (37℃±0.3℃) through a circulating pump, cooling fan, and auxiliary heating module. This avoids interference with cells caused by coil heat generation, recovers and utilizes waste heat, and reduces energy waste. Simultaneously, a thermal effect control device isolated by a heat insulation plate allows for separate verification of the thermal effect, effectively distinguishing the experimental results from those of the magnetic field itself and the thermal effect, thus solving the problem of quantifiable thermal interference in existing devices.

[0020] 3. This controllable magnetic field generator, through the integration of a multi-mode power supply system (such as the ZLG-PSA6000 series), and via DC current stabilization, AC signal generation, and pulse control modules, can seamlessly switch between constant magnetic field (0-50mT), alternating magnetic field (0-10kHz), and pulsed magnetic field (pulse width 100μs-1ms). No coil or hardware replacement is required; precise control of the magnetic field type, intensity, and frequency (intensity fluctuation ≤±1%) can be achieved simply by setting parameters. This meets the diverse magnetic field parameter requirements of different cell experiments, improving the device's versatility and ease of operation. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the isometric three-dimensional structure of the present invention;

[0022] Figure 2 This is a schematic diagram of the Helmholtz coil assembly installation structure of the present invention;

[0023] Figure 3 This is a schematic diagram of the horizontal movement structure of the Helmholtz coil group of the present invention;

[0024] Figure 4 This is a schematic diagram of the installation structure of the petri dish placement component of the present invention;

[0025] Figure 5 This is a three-dimensional structural diagram of the petri dish placement component of the present invention;

[0026] Figure 6 This is a schematic diagram of the installation structure of the petri dish placement plate of the present invention;

[0027] Figure 7 This is a schematic diagram of the heat exchange component installation structure of the present invention;

[0028] Figure 8 This is a three-dimensional structural diagram of the heat exchange component of the present invention;

[0029] Figure 9 This is a schematic diagram of the backplate mounting structure of the present invention;

[0030] Figure 10 This is a schematic diagram of the connection structure between the heat exchange component and the circulating pump of the present invention;

[0031] Figure 11 This is a schematic diagram of the internal cavity structure of the cross of the present invention.

[0032] In the diagram: 1. Magnetic field generating device; 2. Heat insulation plate; 3. Thermal effect comparison device; 4. Magnetic field control console; 5. Scale; 6. Slide rail; 7. Movable base; 8. Cross; 9. Winding core; 10. Helmholtz coil assembly; 11. Mounting bracket; 12. Horizontal guide rod; 13. Horizontal screw; 14. Adjustment handle; 15. Petri dish placement assembly; 16. Driven bevel gear; 17. Driving bevel gear; 18. Driven rod; 19. Petri dish placement plate; 20. Petri dish placement rack; 21. Vertical screw; 22. Petri dish placement slot; 23. Heat exchange assembly; 24. Inlet hose; 25. Outlet hose; 26. Heat exchange coil; 27. Corrugated pipe; 28. Filter screen; 29. ​​Back plate; 30. Circulation pump; 31. Chamber. Detailed Implementation

[0033] When studying the effects of magnetic fields on cells, the deployment of electromagnetic fields must first be clearly defined:

[0034] 1. Magnetic field type:

[0035] A constant magnetic field (DC, such as that generated by permanent magnets or electromagnets, the magnetic field strength does not change with time);

[0036] Alternating magnetic field (AC, such as sine wave or square wave, where the magnetic field strength changes periodically with time, and the frequency f needs to be specified);

[0037] Pulsed magnetic field (the magnetic field strength changes rapidly in a short period of time, and the pulse width, repetition frequency, and peak intensity need to be specified).

[0038] 2. Key parameter range:

[0039] Magnetic field strength: The common range for cell experiments is from microtesla (μT) to millitalas (mT), and some studies can reach the tesla (T) level (such as strong constant magnetic fields);

[0040] Frequency (alternating / pulse): from power frequency (50 / 60Hz) to radio frequency (MHz), the choice should be made based on the research hypothesis (e.g., low frequency may affect ion transport, high frequency may generate heat);

[0041] Exposure duration: short-term (minutes to hours) or long-term (days to weeks), depending on the cell cycle or experimental endpoint.

[0042] Example 1

[0043] In one typical implementation of this application, such as Figure 2-11As shown, a controllable magnetic field generating device includes a magnetic field generating device 1. The magnetic field generating device 1 includes a magnetic field control console 4 and a Helmholtz coil group 10 installed above the magnetic field control console 4. The Helmholtz coil group 10 includes a winding core 9. A coil is wound on the outer surface of the winding core 9. There are two sets of winding cores 9. The two sets of winding cores 9 are symmetrically arranged on the left and right sides above the magnetic field control console 4. The axes of the two sets of winding cores 9 coincide and are parallel. A cross 8 is fixedly installed on the inner wall of the winding core 9. Mounting brackets 11 are fixedly connected to the two sides of the center of the cross 8. A movable base 7 is fixedly connected to the lower end of the mounting brackets 11 on both sides.

[0044] By using a Helmholtz coil assembly 10 and energizing it, cell experiments can be conducted using the magnetic field generated by the Helmholtz coil assembly 10. The magnetic field type can be switched by connecting different power supply types to the Helmholtz coil assembly 10. The coil is wound around the outer periphery of the winding core 9, and both ends of the coil extend into the magnetic field control console 4. The magnetic field control console 4 is equipped with a multi-mode power supply system (DC / AC / pulse switching).

[0045] Multi-mode power supply systems integrate multiple current output functions through modular design and digital control, and typically include the following core modules:

[0046] DC current regulator module: Provides a constant current (e.g., 0-5A) to generate a constant magnetic field;

[0047] AC / Pulse Generation Module: Outputs alternating / pulse current via a function signal generator or pulse controller;

[0048] Power amplifier: Amplifies low-power signals into high currents (such as 100A peak) to drive electromagnets;

[0049] Control system: integrates a microprocessor or FPGA to realize real-time parameter adjustment and mode switching;

[0050] Sensors and feedback: such as gaussmeters and thermocouples, used for closed-loop control of magnetic field strength and temperature;

[0051] The multi-mode power supply system adopts the ZLG-PSA6000 series programmable AC power supply, specifically:

[0052] 1. Generation of a constant magnetic field:

[0053] The power supply is activated in "DC steady current mode." The output current (0-5A) is set via the control system, and the current is amplified by the power amplifier before being input to the coil. For example, when the current is set to 2A, a 1000-turn coil can generate a constant magnetic field of approximately 20mT (calibration with a gaussmeter at the culture dish position is required to eliminate the influence of iron core magnetic saturation). The system uses closed-loop feedback (real-time monitoring with a gaussmeter) to control the magnetic field strength fluctuation within ±1%, ensuring the stability of long-term experiments (such as 7-day cell culture).

[0054] 2. Generation of alternating magnetic fields:

[0055] Switching to "AC mode" activates the function generator, which outputs a sine / square wave signal (frequency 0-10kHz), which is then converted into alternating current by a power amplifier. For example, when studying a 50Hz power frequency magnetic field, the frequency is set to 50Hz and the effective current value to 1A, generating an alternating magnetic field with a peak-to-peak value of 10mT. The oscilloscope monitors the current waveform in real time to ensure no distortion (total harmonic distortion ≤2%).

[0056] 3. Generation of pulsed magnetic fields:

[0057] When "Pulse Mode" is enabled, the pulse generator is set with the following parameters: pulse width 100μs, repetition frequency 1Hz, and peak current 10A. The high-speed amplifier drives the coil to generate a pulse magnetic field with a peak value of 100mT.

[0058] Furthermore, the reason for using the Helmholtz coil group 10 is that the Helmholtz coil group 10 is characterized by a magnetic field uniformity of >90% in the central region, which is the optimal area for placing culture dishes. Culture dishes can be placed within this area. Moreover, the volume of the uniform magnetic field in the middle of the Helmholtz coil group 10 is independent of the number of coil turns N and the current I, and is determined only by the coil radius R and the allowable relative deviation of the magnetic field (the ratio of the difference between the magnetic field at a certain point and the central magnetic field to the central magnetic field). The uniform region is still approximately an ellipsoid (radially symmetrical).

[0059] Therefore, we install a petri dish placement assembly 15 in the middle above the magnetic field control console 4 to support the petri dishes. The petri dish placement assembly 15 is located in the center of the Helmholtz coil assembly 10. The petri dish placement assembly 15 includes a petri dish placement rack 20 fixed in the middle of the upper end of the magnetic field control console 4. Several petri dish placement plates 19 are vertically distributed inside the petri dish placement rack 20. Petri dish placement slots 22 are provided on the left and right sides of the upper end surface of the petri dish placement plate 19.

[0060] In a standard Helmholtz coil assembly 10, the distance d between the two coils is equal to the radius R of the coil. At this time, the volume of the uniform magnetic field in the middle of the Helmholtz coil assembly 10 is the largest, that is, the most culture dish placement plates 19 can be deployed and used. The culture dish placement slots 22 in the culture dish placement plates 19 can hold a sufficient number of culture dishes. By setting up multiple sets of culture dishes, more comparative experimental data can be obtained under the same magnetic field environment.

[0061] However, in specific experiments, both the magnetic field strength and frequency within the key parameter range cause the Helmholtz coil assembly 10 to generate heat during operation. Furthermore, the heat generation intensifies with increasing magnetic field strength and frequency. This thermal effect is unavoidable and significantly impacts cell experiments in the culture dish within the Helmholtz coil assembly 10. Therefore, in specific experiments, if the current in the coils of the Helmholtz coil assembly 10 is increased, the distance between the culture dish placement component 15 and the Helmholtz coil assemblies 10 on both sides should be increased simultaneously to reduce the thermal effect. Secondly, the heat generated by the thermal effect should be recovered and utilized. Specifically:

[0062] A driven rod 18 is rotatably mounted on the top of the petri dish rack 20. A driven bevel gear 16 is fixedly connected to the lower end of the driven rod 18. A driving bevel gear 17 is fixedly fitted on the middle outer surface of the transverse guide rod 12. The driving bevel gear 17 and the driven bevel gear 16 mesh. The driven rod 18 vertically penetrates the center of the petri dish rack 19. Several vertical spirals 21 are provided on the outer surface of the driven rod 18. The vertical spirals 21 are screwed onto the center of the petri dish rack 19. Slide rails 6 are installed on the front and back of the upper end of the magnetic field control console 4. The movable base 7 is slidably mounted on the slide rails 6 on the front and back sides. A transverse guide rod 12 is inserted through the center of the movable base 7 on the left and right sides above the magnetic field control console 4. Symmetrical transverse spirals 13 are provided on the two ends of the transverse guide rod 12. The transverse spirals 13 are screwed onto the center of the movable base 7. An adjustment handle 14 is fixedly connected to the end of the transverse guide rod 12. Heat exchange components 23 are installed at the bottom of several culture dish placement plates 19 inside the rack 20. The heat exchange components 23 include heat exchange coils 26 embedded in the bottom of the culture dish placement plates 19. The heat exchange coils 26 on the same side of the bottom of adjacent culture dish placement plates 19 are connected by corrugated pipes 27. The heat exchange coils 26 on the same side of the bottom of the upper and lower culture dish placement plates 19 are respectively connected to one end of the liquid outlet hose 25 and the liquid inlet hose 24. The other end of the liquid inlet hose 24 is connected to the upper end of the mounting frame 11. The other end of the liquid outlet hose 25 is connected to the circulation pump 30 installed on the mounting frame 11. A back plate 29 is fixedly installed on the front side wall of the culture dish placement rack 20. A filter screen 28 is installed on the back plate 29. A cooling fan is installed on the back plate 29 where the filter screen 28 is located. The inside of the winding core 9 is hollow. The inside of the cross 8 is hollow and connected to the inside of the winding core 9. The upper end of the mounting frame 11 is a hollow structure. The hollow is an interconnected chamber 31.

[0063] The experimenter rotates the adjustment handle 14 and its connected transverse guide rod 12, which drives the winding cores 9 on both sides of the Helmholtz coil group 10 to move apart through the transverse screw 13, increasing the distance between the winding cores 9 and the culture dish placement assembly 15, and reducing the influence of thermal effects on cell experiments. During this process, the distance d between the two coil groups gradually becomes greater than the coil radius R. The axial uniform region of the volume of the uniform magnetic field in the middle of the Helmholtz coil group 10 shrinks more significantly than the radial region, and the overall volume is smaller than the standard case. Therefore, during this process, the volume of the uniform magnetic field in the middle of the Helmholtz coil group 10 decreases. To reduce the relative deviation, we reduce the unfolding of the culture dish placement plate 19 in the central region.

[0064] Specifically, when the transverse guide rod 12 rotates, the active bevel gear 17 on its surface rotates synchronously. The active bevel gear 17 drives the driven bevel gear 16 and its driven rod 18 to rotate synchronously. The vertical spiral 21 on the surface of the driven rod 18 drives the culture dish placement plates 19 to contract relative to each other, reducing relative deviation and ensuring that all cell culture dishes are within the uniform magnetic field at the center of the Helmholtz coil group 10. At the same time, it also reduces the impact of thermal effects on cell experiments.

[0065] In addition, we also recover and utilize the heat generated by the Helmholtz coil assembly 10, specifically:

[0066] Because cells need to be cultured at 37°C, when the ambient temperature is insufficient, we use the thermal effect of the Helmholtz coil assembly 10 for heating. First, the hollow winding core 9 and the cross 8 are filled with heat exchange fluid (kerosene). Since the cross 8 is a thermally conductive core, the heat generated by the coil is directly transferred to the heat exchange fluid through the winding core 9. Then, the circulation pump 30 is turned on, and the hot exchange fluid is pumped into the heat exchange coil 26 through the inlet hose 24. Heat exchange occurs between the heat exchange coil 26 and the culture dish placement plate 19. Specifically, the input end of the circulation pump 30 extends into the chamber 31, the output end of the circulation pump 30 is connected to the port of the inlet hose 24, and the port of the outlet hose 25 extends into the chamber 31. During heat exchange, the heat generated by the coil is transferred to the heat exchange fluid in the chamber 31. The circulation pump 30 pumps the hot exchange fluid into the heat exchange coil 26 and returns it to the chamber 31 through the outlet hose 25, thus achieving heat exchange.

[0067] It is important to note that if the heat exchange medium temperature is below 37°C, it needs to be heated further. Similarly, if the heat exchange medium temperature is above 37°C, the cooling fan needs to be turned on to dissipate heat from the environment surrounding the culture dish placement plate 19, thereby ensuring a constant ambient temperature. Continuous monitoring is required. Specifically:

[0068] The culture dish placement board 19 is equipped with a thermocouple inside, which monitors the temperature in real time and transmits it to the control system:

[0069] When the temperature < 36.5 °C, increase the power of the circulation pump (increase the hot oil flow rate) and use the waste heat of the coil for heating; if the waste heat is insufficient, start the auxiliary heating module (power 50 W) inside the mounting rack 11;

[0070] When the temperature > 37.5 °C, start the cooling fan on the back panel 29 (wind speed 2 m / s), and cooperate with the filter screen 28 (dust-proof and breathable) to accelerate air circulation; at the same time, reduce the power of the circulation pump to reduce heat input.

[0071] Regarding the characteristics of the Helmholtz coil group 10, the conclusions are currently known, and this invention does not perform excessive calculations. The conclusions are as follows:

[0072] When the standard spacing d = R, the uniform volume is the largest: deviating from this spacing (whether increasing or decreasing), the uniform area will shrink, especially the uniformity in the axial direction (z direction) is more sensitive to the spacing;

[0073] The smaller the spacing (d < R): both the radial and axial uniform areas are significantly reduced, and the axial shrinkage is more obvious;

[0074] The larger the spacing (d > R): the shrinkage of the axial uniform area is more significant than the radial direction, and the overall volume is smaller than the standard situation.

[0075] Furthermore, in the above solution, a scale 5 is provided at the upper end of the magnetic field console 4 for observing the distance between the two coils in the Helmholtz coil group 10.

[0076] Furthermore, in the above solution, a transparent glass door is rotatably installed on the rear side wall of the back panel 29 to facilitate observing the situation of the cell culture dish.

[0077] Furthermore, in the above solution, the culture dish placement rack 20 and the culture dish placement board 19 inside it are made of PET plastic, and the heat exchange coil 26 is made of copper tubing to avoid magnetic induction of materials caused by the magnetic field and reduce experimental errors.

[0078] Embodiment 2

[0079] As Figure 1 shown, the magnetic field generating device 1 and the thermal effect control device 3, the magnetic field generating device 1 and the thermal effect control device 3 are separated by a heat insulation board 2, and the magnetic field generating device 1 and the thermal effect control device 3 include a magnetic field console 4 and a Helmholtz coil group 10 installed above the magnetic field console 4.

[0080] The difference between this embodiment and Embodiment 1 is that this embodiment designs a thermal effect comparison device 3. The difference between this device and the magnetic field generating device 1 is that we do not energize the coil in the thermal effect comparison device 3, so it will not produce a thermal effect. The degree of influence of the thermal effect is compared by this method.

[0081] Experimental Example 1

[0082] Experimental procedure (taking the effect of alternating magnetic field on stem cell differentiation as an example):

[0083] 1. Apparatus preparation: Adjust the coil spacing to d = R (10cm), unfold the culture dish placement plate 19 to 5 layers, and place the 6-well culture dish containing stem cells (1×10⁶ cells per well) through the transparent glass door. 5 (cells), close the glass door (to avoid interference from external airflow);

[0084] 2. Parameter settings: The multi-mode power system is set to a 50Hz alternating magnetic field, a current of 1A (corresponding to a magnetic field strength of 10mT), and an exposure time of 72h.

[0085] 3. Environmental monitoring: Start closed-loop temperature control to ensure the culture environment is 37℃±0.3℃. Record the magnetic field strength every 2 hours with a gaussmeter. If the deviation exceeds 2%, the current will be automatically adjusted.

[0086] 4. Data collection: After exposure, observe cell morphology through the glass door, remove the culture dish and detect differentiation markers (such as alkaline phosphatase activity).

[0087] Meanwhile, to distinguish between magnetic field effects and thermal effects, this experimental example sets up a thermal effect control device 3, which is isolated from the magnetic field generating device 1 by a heat insulation plate 2 (heat insulation coefficient ≥0.03W / (m·K)) to ensure that the environment does not interfere with each other.

[0088] The Helmholtz coil assembly, culture dish placement components, and heat exchange system of the thermal effect control device 3 are completely identical to those of the magnetic field generating device 1 (the number of coil turns, the number of culture dishes, and the temperature control parameters are all the same).

[0089] The coil of the thermal effect control device 3 is not energized (no magnetic field is generated), and the temperature is maintained at 37℃±0.5℃ only through the heat exchange component 23 and the cooling fan to simulate the thermal environment of the magnetic field generating device.

[0090] Comparison logic: By comparing the cell experiment results of magnetic field generating device 1 (magnetic field + thermal effect) with thermal effect control device 3 (thermal effect only), the interference of thermal effect can be accurately eliminated, and the influence of the magnetic field itself on cells (such as proliferation rate and gene expression differences) can be clarified.

[0091] To clarify the quantitative relationship between current change and distance adjustment, the following derivation is made based on the thermal effect model of the Helmholtz coil, the requirement for magnetic field uniformity, and the data from Experiment Example 1:

[0092] 1. Coil spacing adjustment formula

[0093] The heat generation power P of the coil is proportional to the square of the current: P = kI 2 (k is the thermal resistance coefficient of the coil)

[0094] The thermal effect on the petri dish is inversely proportional to the square of the distance. To maintain an equivalent thermal effect, the following must be satisfied:

[0095]

[0096] Reference point: I in Experiment Example 1 ref When d = 1A, ref =R=10cm (standard spacing).

[0097] The general formula is obtained as follows:

[0098] 2. Formula for adjusting the spacing between petri dish placement plates

[0099] Axial half-height H of the uniform magnetic field region d Inversely proportional to the coil spacing d (when d>R):

[0100] Let the number of petri dish layers be N (N = 5 in the experimental example), and the spacing between the plates be s, so that all plates are in the uniform region (|z| ≤ H). d The condition must satisfy: (N-1)·s≤2H d Substituting d∝I, we get s∝1 / I.

[0101] Reference point: I ref When = 1A, s ref =2cm (from H) d =Calculated at 4cm).

[0102] The general formula is obtained as follows:

[0103]

[0104] Based on the above formula, the distance adjustment corresponding to typical current values ​​is as follows:

[0105]

[0106] Based on the table above, when the rotating adjustment handle changes d, the driven bevel gear 16 is automatically driven by the active bevel gear 17 to rotate the driven rod (18), which in turn drives the vertical spiral (21) to synchronously shrink / expand the culture dish placement plate (19) according to the ratio s∝1 / d, ensuring that the relationship in the table above is met.

[0107] The magnetic field control console scale (5) is used to calibrate the initial value of d (aligned to 10cm when I = 1A).

[0108] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A controllable magnetic field generating device, characterized in that: include A magnetic field generating device (1) and a thermal effect comparison device (3) are separated by a heat insulation plate (2). The magnetic field generating device (1) and the thermal effect comparison device (3) include a magnetic field control console (4) and a Helmholtz coil assembly (10) mounted on the magnetic field control console (4). The Helmholtz coil assembly (10) includes a winding core (9), and a coil is wound on the outer surface of the winding core (9). There are two sets of winding cores (9), which are symmetrically arranged on the left and right sides above the magnetic field control console (4). The axes of the two sets of winding cores (9) coincide and are parallel. A cross (8) is fixedly installed on the inner wall of the winding core (9). Mounting brackets (11) are fixedly connected to the center of the cross (8) on both sides. A movable base (7) is fixedly connected to the lower end of the mounting brackets (11) on both sides. A slide rail (6) is installed on the front and back of the upper end of the magnetic field control console (4). The movable base (7) is slidably installed on the slide rail (6) on the front and back sides. A transverse guide rod (12) is inserted through the center of the movable base (7) on the left and right sides above the magnetic field control console (4). Symmetrical transverse spirals (13) are provided on the two ends of the transverse guide rod (12). The transverse spirals (13) are screwed into the center of the movable base (7) by thread. An adjustment handle (14) is fixedly connected to the end of the transverse guide rod (12). A petri dish placement assembly (15) is installed above the center of the magnetic field control console (4) to support the petri dish. The petri dish placement assembly (15) is located at the center of the Helmholtz coil assembly (10).

2. The controllable magnetic field generating device according to claim 1, characterized in that: The upper end of the magnetic field control console (4) is provided with a scale (5).

3. The controllable magnetic field generating device according to claim 2, characterized in that: The petri dish placement assembly (15) includes a petri dish placement rack (20) fixed in the middle of the upper end of the magnetic field control console (4). A driven rod (18) is rotatably mounted on the top of the petri dish placement rack (20). A driven bevel gear (16) is fixedly connected to the lower end of the driven rod (18). An active bevel gear (17) is fixedly fitted on the middle outer surface of the transverse guide rod (12). The active bevel gear (17) and the driven bevel gear (16) mesh. Several petri dish placement plates (19) are vertically distributed inside the petri dish placement rack (20). The driven rod (18) is vertically inserted into the center of the petri dish placement plate (19). Several vertical spirals (21) are provided on the outer surface of the driven rod (18). The vertical spirals (21) are screwed into the center of the petri dish placement plate (19) by threads. Petri dish placement grooves (22) are provided on the left and right sides of the upper end face of the petri dish placement plate (19).

4. A controllable magnetic field generating device according to claim 3, characterized in that: The front side wall of the petri dish rack (20) is fixedly provided with a back plate (29), a filter screen (28) is installed on the back plate (29), and a cooling fan is installed on the back plate (29) where the filter screen (28) is located.

5. A controllable magnetic field generating device according to claim 4, characterized in that: A transparent glass door is rotatably mounted on the rear side wall of the back panel (29).

6. A controllable magnetic field generating device according to claim 5, characterized in that: A heat exchange assembly (23) is installed at the bottom of several culture dish placement plates (19) in the culture dish placement rack (20). The heat exchange assembly (23) includes a heat exchange coil (26) embedded in the bottom of the culture dish placement plate (19). The heat exchange coils (26) on the same side of the bottom of adjacent culture dish placement plates (19) are connected by a corrugated pipe (27). The heat exchange coils (26) on the same side of the bottom of the upper and lower culture dish placement plates (19) are respectively connected to one end of the liquid outlet hose (25) and the liquid inlet hose (24). The other end of the liquid inlet hose (24) is connected to the upper end of the mounting frame (11). The other end of the liquid outlet hose (25) is connected to the circulation pump (30) installed on the mounting frame (11).

7. A controllable magnetic field generating device according to claim 6, characterized in that: The petri dish rack (20) and its internal petri dish plate (19) are made of PET plastic, and the heat exchange coil (26) is made of copper pipe.

8. A controllable magnetic field generating device according to claim 7, characterized in that: The interior of the winding core (9) is hollow, the interior of the cross (8) is hollow and connected to the interior of the winding core (9), the upper end of the mounting bracket (11) is hollow, and the hollow is a cavity (31) that is interconnected.

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