Supercooling medium rapid-freezing method based on superimposed space electric field

Abstract

This application provides a method for rapid freezing of a supercooled medium based on a superimposed spatial electric field, comprising: acquiring the three-dimensional spatial arrangement of biological tissue fibers in the supercooled medium; identifying the fiber arrangement angle and fiber coverage density of the biological tissue fibers; collecting the preliminary electric field direction and polarization intensity of each region of the superimposed spatial electric field to obtain the average polarization intensity; determining the unidirectional electric field coverage rate based on the fiber arrangement angle; determining the polarization intensity of fibers with different orientations based on the unidirectional electric field coverage rate and the fiber coverage density; extracting the polarization intensity gradient direction of each region after polarization intensity distribution adjustment; and identifying the orientation angle of ice crystal growth based on the spatial correspondence between the polarization intensity gradient direction and the fiber arrangement angle.

Description

Technical Field

[0001] This invention relates to the field of information technology, and in particular to a method for rapid freezing of supercooled media based on superimposed spatial electric fields. Background Technology

[0002] Low-temperature quick-freezing preservation of biological tissues plays a crucial role in food processing, medical cold chain, and biological sample preservation. The morphology and growth direction of ice crystals during freezing directly determine the taste, nutrient retention, and cell integrity of the thawed tissue. Reducing the damage of ice crystals to the fibrous structure is an important indicator for measuring the level of freezing technology.

[0003] Most common quick-freezing methods rely on rapid cooling or the application of auxiliary fields in a fixed direction to accelerate cold transfer. However, these methods have limited effectiveness when dealing with biological tissues with significant differences in internal structure. They lack the ability to identify the actual fiber orientation within the tissue, there is no correlation between cold delivery and tissue morphology, and the freezing process is more akin to overall cooling rather than targeted regulation, making it difficult to adapt to the reality of significant differences in physical properties across different parts of the tissue.

[0004] The fibers within biological tissues are not arranged in a regular parallel pattern, but rather are distributed in an alternating pattern with varying angles and coverage densities. The gaps between these fibers vary in size and direction, and these gaps are the key locations where water molecules aggregate and eventually freeze. When a fixed-direction electric field is used to polarize water molecules in a supercooled medium, the electric field can only be parallel to the direction of some gaps. It is difficult to align with those gaps whose directions deviate, resulting in insufficient polarization of water molecules in the deviated areas. Consequently, the ability to store cold energy is significantly lower than average, forming what is known as a low-energy-storage gap region.

[0005] This uneven polarization becomes apparent during the freezing initiation stage: water molecules in the gap regions that match the direction of the electric field are arranged neatly, and ice crystals grow in an orderly and directional manner along the gaps; while water molecules in the gap regions with low polarization are arranged randomly, and ice crystals grow in random directions, easily piercing the fiber wall laterally, tearing the connections between fiber bundles, resulting in juice loss, loose texture, or even local collapse after thawing.

[0006] Therefore, the key issue in improving the quality of quick-freezing biological tissues is how to apply an electric field matching the direction of the fiber inclination and coverage density to the interstitial regions with different orientations, so that water molecules in the supercooled medium can achieve ordered polarization in each interstitial region, thereby guiding ice crystals to grow along the fiber interstitial direction rather than traversing the fibers. Summary of the Invention

[0007] This invention provides a method for rapid freezing of supercooled media based on superimposed spatial electric fields, comprising: The three-dimensional spatial arrangement of biological tissue fibers immersed in a supercooled medium is obtained. The fiber arrangement angle and fiber coverage density are identified based on the three-dimensional spatial arrangement. The preliminary electric field direction and polarization intensity of each region of the superimposed spatial electric field are collected. Based on the fiber arrangement angle, the fiber coverage density, and the polarization intensity of each region, the polarization intensity distribution of fibers with different orientations is determined, and the regions with low polarization intensity in the polarization intensity distribution are identified as gap regions with low energy storage. Determine the deviation angle between the fiber orientation of the gap region with low energy storage and the direction of the initial electric field, and adjust the electric field direction according to the deviation angle to obtain the adjusted polarization intensity distribution; The electric field switching cycle is generated according to the adjusted polarization intensity distribution. The electric field direction is switched in time according to the electric field switching cycle to form a superimposed spatial electric field covering different fiber orientations, so that the supercooled medium in each gap region is kept in an orderly polarization and stores cold energy. Identify the orientation angle of ice crystal growth in each region, determine the deviation of the ice crystal growth angle between the orientation angle and the fiber gap direction, adjust the electric field switching cycle according to the ice crystal growth angle deviation, so that the supercooled medium is uniformly polarized in the fiber gap, and control the ice crystal to grow in a directional manner along the fiber gap direction.

[0008] Furthermore, the process of obtaining the three-dimensional spatial arrangement of biological tissue fibers immersed in a supercooled medium, identifying the fiber arrangement angle and fiber coverage density based on the three-dimensional spatial arrangement, and acquiring the preliminary electric field direction and polarization intensity of the superimposed spatial electric field in each region includes: An ultrasonic scanner was used to scan the biological tissue immersed in the supercooled medium layer by layer to obtain cross-sectional image data. The fiber contour coordinates in the cross-sectional image data are extracted by an image recognition algorithm. The three-dimensional spatial trajectory of the fiber bundle is constructed according to the spatial connection relationship of the corresponding fiber contour coordinates between adjacent layers, and the three-dimensional spatial arrangement is obtained. For the three-dimensional spatial arrangement, the angle between the central axes of adjacent fiber bundles is calculated to obtain the fiber arrangement angle, and the number of fiber bundles in each fiber group per unit volume is counted to obtain the fiber coverage density. An array of electrode plates is arranged in the quick-freezing device according to the fiber coverage density, a uniform electric field is applied, the direction of the uniform electric field is taken as the initial electric field direction, and a sensor probe is used to measure the local polarization intensity in different fiber group regions to obtain the polarization intensity of each region.

[0009] Furthermore, determining the polarization intensity distribution of fibers with different orientations based on the fiber arrangement angle, the fiber coverage density, and the polarization intensity of each region includes: Obtain the principal axis direction of each fiber bundle in the three-dimensional spatial arrangement, and calculate the angle between the principal axis direction and the initial electric field direction; The unidirectional electric field coverage rate is obtained by calculating the ratio of the number of fiber bundles with included angles less than a preset angle threshold to the total number of fiber bundles. Based on the unidirectional electric field coverage rate, fiber coverage density data of uncovered fiber areas are extracted, and polarization intensity adjustment coefficients for different areas are obtained through function mapping. The initial polarization intensity value of each region is corrected by the polarization intensity adjustment coefficient, and the polarization intensity value of each oriented fiber under the current electric field is calculated by combining the dielectric constant of different oriented fiber groups, so as to obtain the polarization intensity distribution of the different oriented fibers.

[0010] Furthermore, identifying regions with low polarization intensity in the polarization intensity distribution as gap regions with low energy storage includes: The weighted average value of the polarization intensity at each measurement point is calculated to obtain the mean value of the polarization intensity; The polarization intensity at each measurement point is compared with the average polarization intensity point by point, and the measurement points with polarization intensity lower than the average polarization intensity point are marked as low polarization regions. Based on the positional relationship between the low polarization region and the three-dimensional spatial arrangement, the low polarization region located between fiber bundles is determined to be the gap region with low energy storage. The absolute value of the difference between the polarization intensity at each point in the gap region with low energy storage and the mean value of the polarization intensity is calculated to obtain the energy storage difference value.

[0011] Furthermore, it also includes: The gradient change detection method is used to identify the abrupt boundary of polarization intensity in the polarization intensity distribution. The high polarization intensity region inside the abrupt boundary is determined to be the fiber interior, and the low polarization intensity region outside the abrupt boundary is determined to be the fiber gap. The average value of the polarization intensity at the measurement points inside the fiber and in the fiber gap is calculated respectively to obtain the energy storage value inside the fiber and the energy storage value in the fiber gap.

[0012] Furthermore, determining the deviation angle between the fiber orientation in the gap region with low energy storage and the initial electric field direction, and adjusting the electric field direction according to the deviation angle to obtain the adjusted polarization intensity distribution includes: Extract the principal direction vector of the fiber arrangement in the gap region where the energy storage is low, calculate the angle between the principal direction vector and the direction vector of the initial electric field direction to obtain the deviation angle, and determine the electric field rotation angle based on the deviation angle. The phase difference of each electrode in the electrode plate array is adjusted according to the electric field rotation angle. The electrode plate array adopts a multi-phase power supply method. By adjusting the phase relationship between each phase, the electric field direction is rotated to be parallel to the fiber direction of the gap region with low energy storage, and the adjusted electric field configuration parameters are obtained. An electric field is applied to the gap region with low energy storage using the adjusted electric field configuration parameters, so that the water molecules in the supercooled medium are kept in an orderly arrangement, and the adjusted polarization intensity distribution is obtained. The temperature of the gap region with low energy storage is controlled to be below the freezing point and above the nucleation temperature, so that the subcooled medium is kept in a subcooled liquid state to store cold energy.

[0013] Furthermore, the step of generating the electric field switching period based on the adjusted polarization intensity distribution includes: Based on the adjusted polarization intensity distribution, the time required for the polarization intensity in different regions to reach stability is calculated, and the maximum value of the stability time in each region is taken as the basic period length. Multiple switching time points are set within the basic cycle length to generate the electric field switching cycle, which includes the switching time and duration. The electrode plate array is controlled according to the electric field switching cycle. At each switching moment, the energy storage value inside the fiber and the energy storage value between the fibers are recorded, and the difference between the two is calculated to form a difference sequence. The difference sequence is cumulatively averaged over time to obtain the difference change trend. The ratio of the energy storage value inside the fiber to the energy storage value between the fibers is calculated based on the difference change trend to assess the degree of energy storage balance. The electric field switching cycle is then corrected based on the degree of energy storage balance.

[0014] Furthermore, the step of identifying the orientation angle of ice crystal growth in each region, determining the ice crystal growth angle deviation between the orientation angle and the fiber gap direction, and adjusting the electric field switching cycle according to the ice crystal growth angle deviation to control the directional growth of ice crystals along the fiber gap direction includes: Remove the electric field to cause the supercooled medium to crystallize instantaneously, and record the polarization intensity value and spatial coordinates of each region at the moment of crystallization triggering. The polarization intensity difference between adjacent measurement points is calculated based on the polarization intensity value and spatial coordinates, and the distance is used to obtain the polarization intensity gradient magnitude at each point. The gradient direction vector is determined by the components of the gradient on the three-dimensional coordinate axes. Calculate the angle between the gradient direction vector and the fiber arrangement direction at the corresponding position to identify the orientation angle of ice crystal growth in each region; The orientation angle is compared point by point with the growth direction along the fiber gap, and the angle difference is calculated as the ice crystal growth angle deviation. The spatial distribution of the deviation points is statistically analyzed to obtain the angle deviation distribution map. Based on the angle deviation distribution map, extract the electric field switching period parameters corresponding to the deviation region, and change the polarization establishment rate of the deviation region by adjusting the switching time interval to generate the adjusted electric field switching period. The electric field is reapplied using the adjusted electric field switching cycle. The polarization intensity value at each point in the fiber gap is monitored. The ratio of the standard deviation to the average value of the polarization intensity is calculated. When the ratio of the standard deviation to the average value is lower than the preset uniformity threshold, it is determined that the supercooled medium is uniformly polarized in the fiber gap, and the ice crystals are controlled to grow directionally along the fiber gap direction.

[0015] The technical solutions provided by the embodiments of the present invention may include the following beneficial effects: This invention discloses a method for rapid freezing of supercooled media based on superimposed spatial electric fields, addressing the problem that the complex arrangement of fibers in biological tissues makes it difficult to achieve uniform ice crystal growth using traditional rapid freezing methods. The method involves using ultrasonic scanning to obtain the three-dimensional spatial arrangement of fibers and identify the fiber arrangement angles and coverage density. A preliminary electric field is applied using superimposed spatial electric field technology, and the polarization intensity of each region is measured to identify gap regions with low energy storage due to polarization intensity below the average. For these regions, the electric field rotation angle is determined based on the fiber arrangement deviation angle. The electric field direction is dynamically rotated by adjusting the phase difference of the electrode array through a multi-phase power supply method, ensuring that the electric field is parallel to the fiber direction in the gap region. This promotes the orderly arrangement of water molecules in the supercooled medium and maintains the supercooled liquid state for cold storage. By generating an electric field switching cycle and monitoring the energy storage balance inside and outside the fibers, the polarization intensity gradient direction is extracted to identify the ice crystal growth orientation angle. The electric field switching cycle is then adjusted to correct the polarization intensity gradient direction, ultimately achieving uniform polarization of the supercooled medium in the fiber gaps. This controls the directional growth of ice crystals along the fiber gap direction, significantly reducing the damage to the fiber structure caused by ice crystals and improving the quality retention of frozen biological tissues. Attached Figure Description

[0016] Figure 1 This is a flowchart of a method for rapid freezing of a superimposed spatial electric field based on the present invention.

[0017] Figure 2 This is a schematic diagram of a method for rapid freezing of a superimposed spatial electric field based on the present invention.

[0018] Figure 3 This is another schematic diagram of a superimposed spatial electric field-based method for rapid freezing of supercooled media according to the present invention. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and thoroughly described below with reference to the accompanying drawings. The described embodiments are merely some embodiments of the present invention.

[0020] like Figures 1-3This embodiment of a method for rapid freezing of a superimposed spatial electric field in a superimposed spatial electric field may specifically include: This invention provides a method for rapid freezing of superimposed spatial electric fields in a supercooled medium. This method utilizes the unique phase transition characteristics of the supercooled medium to control the electric field distribution within the interfibrillary spaces of biological tissues, thereby achieving directional and controllable ice crystal growth and improving the quality of frozen biological tissues. Figure 1 This is a schematic flowchart of a superimposed spatial electric field-based rapid freezing method for supercooled media provided in an embodiment of the present invention, as shown below. Figure 1 As shown, the method includes the following steps.

[0021] This invention provides a method for rapid freezing of superimposed spatial electric fields using superimposed spatial electric fields. This method achieves directional and controllable ice crystal growth by regulating the electric field distribution in the interfibrillary spaces of biological tissues and utilizing the phase transition characteristics of the supercooled medium. This avoids mechanical damage to the fiber structure caused by ice crystal growth, thereby improving the quality of the frozen biological tissues. Figure 1 This is a schematic flowchart of a rapid freezing method for superimposed spatial electric fields provided in an embodiment of the present invention. Figure 1 As shown, the method includes the following steps.

[0022] Step S1: Obtain the three-dimensional spatial arrangement of biological tissue fibers immersed in a supercooled medium, identify the fiber arrangement angle and fiber coverage density based on the three-dimensional spatial arrangement, and collect the preliminary electric field direction and polarization intensity of the superimposed spatial electric field in each region.

[0023] Biological tissues exhibit complex fibrous network distribution patterns at the microscopic level. Fiber bundles possess specific arrangement and density distribution characteristics in three-dimensional space, with significant differences in fiber arrangement among different tissue types. Muscle tissue fibers are arranged in parallel bundles, while connective tissue fibers form a network-like interwoven structure. The spatial characteristics of fiber arrangement directly affect the propagation path of the electric field and the intensity of polarization response within the tissue. Therefore, accurately obtaining information on the three-dimensional spatial arrangement of fibers is fundamental for subsequent electric field modulation.

[0024] Step S11: Use an ultrasonic scanner to scan the biological tissue immersed in the supercooled medium layer by layer to obtain cross-sectional image data.

[0025] The ultrasonic scanner emits sound waves in the range of 5 MHz to 15 MHz to balance penetration depth and spatial resolution. The sound waves travel at approximately 1500 meters per second in the supercooled medium. When the sound waves enter the fiber bundle from the supercooled medium, partial reflection occurs at the interface; the intensity of the reflected echo is proportional to the difference in acoustic impedance between the two media. The echo signal received by the probe is amplified and converted from analog to digital to form digital image data containing spatial location and signal intensity.

[0026] During scanning, the probe is kept in perpendicular contact with the tissue surface to avoid image distortion caused by tilt angles. Scanning begins at one end of the tissue, with the probe moving at a constant speed along a preset trajectory. After scanning each cross-section, the probe is raised or lowered by a fixed step size to move to the next scanning layer, progressively covering the entire three-dimensional space of the tissue. The scanning interval between adjacent layers is set to 0.1 mm to 0.5 mm to ensure the capture of the spatial continuity of the fiber bundles. Each cross-sectional image contains several pixels, and each pixel records the echo intensity value at that location. The echo intensity at the fiber bundle location is higher than that in the interfiber gap region, creating a contrasting image feature. By setting an intensity threshold, the fiber bundle region can be initially separated from the background region.

[0027] Step S12: Extract fiber contour coordinate points from the cross-sectional image data using an image recognition algorithm, and construct a three-dimensional spatial trajectory of the fiber bundle based on the spatial connection relationship of the corresponding fiber contour coordinate points between adjacent layers to obtain the three-dimensional spatial arrangement.

[0028] The image recognition algorithm first performs noise reduction and contrast enhancement preprocessing on the cross-sectional image, and then extracts the contour boundary of the fiber bundle using an edge detection operator. The detected boundary points are connected and closed to form a complete fiber contour curve. Each contour curve consists of a series of coordinate points that record the spatial position of the fiber bundle within the cross-section.

[0029] The coordinates of fiber contours between adjacent layers are established through spatial matching. For any fiber contour in any layer, the contour with the closest shape and the smallest center distance in adjacent layers is identified as the corresponding fiber. The center points of the corresponding fibers in different layers are connected sequentially according to the scanning order to form a spatial curve that runs through multiple layers, which is the three-dimensional spatial trajectory of the fiber bundle. The set of three-dimensional spatial trajectories of all fiber bundles constitutes the three-dimensional spatial arrangement of biological tissue fibers, containing both the orientation information of each fiber bundle and reflecting the spatial positional relationship between fiber bundles. Some fiber bundles are arranged in parallel, and their spatial trajectories maintain a constant spacing; some fiber bundles are arranged in a crossing or twisting manner, and their spatial trajectories are close to or even intersect each other in some areas.

[0030] Step S13: For the three-dimensional spatial arrangement, calculate the angle between the central axes of adjacent fiber bundles to obtain the fiber arrangement angle, count the number of fiber bundles in each fiber group per unit volume, and obtain the fiber coverage density.

[0031] The central axis of a fiber bundle is a spatial curve connecting the center points of its profile in different cross-sectional layers. The central axis typically has a certain degree of curvature; a least-squares straight-line fit is performed on it to obtain a direction vector representing its overall orientation. The angle between the two direction vectors is obtained by calculating the vector dot product and inverse cosine; this angle represents the fiber alignment angle between adjacent fiber bundles, reflecting their relative orientation in space. This method will be used for all subsequent calculations of the angle between the two direction vectors in this paper, and will not be repeated here.

[0032] When calculating fiber coverage density, the three-dimensional space is divided into several cubic units, with each unit having a side length of 1 mm, roughly equivalent to the diameter of a fiber bundle. The number of fiber bundles whose trajectories intersect with the unit's spatial range is counted. This number is then divided by the unit's volume to obtain the fiber coverage density of that region. The coverage density in densely fiber-rich muscle tissue regions can reach 50 to 80 fibers per cubic millimeter, while in sparsely fiber-rich regions it is only 10 to 20 fibers per cubic millimeter.

[0033] Step S14: Arrange an electrode plate array in the quick-freezing device according to the fiber coverage density, apply a uniform electric field, take the direction of the uniform electric field as the initial electric field direction, and use a sensor probe to measure the local polarization intensity in different fiber group regions to obtain the polarization intensity of each region.

[0034] The electrode array consists of multiple pairs of parallel copper or aluminum alloy electrode plates arranged in a matrix layout, uniformly distributed in both horizontal and vertical directions to form a cross-grid structure. Areas with higher fiber coverage density have denser electrode arrangements to achieve precise electric field control. Each pair of electrode plates is connected to an independent power supply module, enabling the application of different voltages and phases.

[0035] The initial electric field was applied synchronously to all electrode plates, with the field direction along the main axis of the biological tissue and substantially parallel to the orientation of most fiber bundles. The applied electric field strength was set within the range of 5 kV to 1 kV per meter, determined based on tolerance test data to avoid causing electrical shock damage to the biological tissue. After the electric field was applied, polar molecules in the supercooled medium and biological tissue aligned directionally under the influence of the electric field, forming a macroscopic polarization phenomenon.

[0036] Sensor probes are pre-arrayed at various measurement points within the biological tissue, maintaining their fixed positions during the quick-freezing process. Each probe contains a miniature electric field sensing chip, converting local electric field intensity into an electrical signal output. The probes are less than 1 mm in size to allow for precise measurements deep within the gaps between fiber bundles. The electric field intensity value is recorded after the signal stabilizes. Inside the fiber bundles, due to the difference in dielectric constant between the fiber material and the supercooled medium, the electric field is refracted and distorted at the interface, resulting in a higher electric field intensity inside the fibers compared to the interfiber regions. Polarization intensity equals the product of the vacuum dielectric constant, the dielectric susceptibility of the medium, and the electric field intensity. Since the dielectric susceptibility of the supercooled medium is constant, the measured electric field intensity value directly reflects the relative magnitude of the polarization intensity at that location.

[0037] Step S2: Based on the fiber arrangement angle, the fiber coverage density, and the polarization intensity of each region, determine the polarization intensity distribution of fibers with different orientations, and identify the regions with low polarization intensity in the polarization intensity distribution as gap regions with low energy storage.

[0038] The direction of a unidirectional electric field remains constant in space. When biological tissue fibers are arranged in multiple directions, the unidirectional electric field can only effectively polarize fibers with some orientations, and fibers with different orientations exhibit different polarization intensity responses under the same electric field conditions.

[0039] Step S21: Obtain the principal axis direction of each fiber bundle in the three-dimensional spatial arrangement, and calculate the angle between the principal axis direction and the initial electric field direction.

[0040] The principal axis direction of a fiber bundle is the normalized direction vector of the straight line fitted to the central axis of the fiber bundle. All fiber bundles arranged in three-dimensional space are traversed, and their principal axis directions are extracted one by one. The initial electric field direction is consistent with the direction of the electric field lines when the electric field is applied to the electrode array, and is also represented by a normalized direction vector. The angle directly affects the polarization efficiency of the fiber bundle: when the angle is close to 0°, the electric field drives the polar molecules within the fiber to align axially to the maximum extent, resulting in the maximum polarization intensity; when the angle is close to 90°, the long axis of the fiber restricts the lateral movement of the molecules, and the polarization intensity decreases significantly.

[0041] Step S22: Calculate the ratio of the number of fiber bundles with included angles less than a preset angle threshold to the total number of fiber bundles to obtain the unidirectional electric field coverage rate.

[0042] The preset angle threshold was set to 45°, calibrated based on experimental data of polarization response of fibers with different orientations. Experiments showed that when the included angle exceeded 45°, the fiber polarization intensity dropped to less than 70% of that in parallel orientation. All identified fiber bundles were examined, and the number of bundles with included angles less than the threshold was counted. This number was divided by the total number of fiber bundles to obtain the unidirectional electric field coverage. Fibers exceeding the threshold were considered not effectively covered by the unidirectional electric field. Muscle tissue fibers are relatively regularly arranged, with a coverage rate of 0.7 to 0.9; connective tissue fibers are more irregularly arranged, with a coverage rate possibly only 0.3 to 0.5. A lower coverage rate indicates the presence of a large number of unpolarized fiber regions, which are prone to uneven ice crystal growth during freezing.

[0043] Step S23: Extract fiber coverage density data of uncovered fiber areas based on the unidirectional electric field coverage rate, and obtain polarization intensity adjustment coefficients for different areas through function mapping.

[0044] The uncovered fiber regions represent the spatial locations of fiber bundles where the angle between the main axis and the electric field direction exceeds a threshold, exhibiting a dispersed or locally clustered distribution in three-dimensional space. A function mapping establishes a mathematical relationship between fiber coverage density and a polarization intensity adjustment coefficient, which is obtained by fitting experimental data. In regions with higher fiber coverage density, the overall polarization intensity is more significantly influenced by the dielectric properties of the fiber material itself; in regions with lower fiber coverage density, the polarization intensity depends more on the polarization response of the supercooled medium. The adjustment coefficient ranges from 0.5 to 1.5, with a coefficient greater than 1 indicating that the actual polarization intensity in that region is higher than the theoretical value, and a coefficient less than 1 indicating that it is lower than the theoretical value. By introducing the adjustment coefficient, the actual polarization intensity distribution in different regions under a unidirectional electric field can be predicted more accurately.

[0045] Step S24: Correct the initial polarization intensity value of each region using the polarization intensity adjustment coefficient, and calculate the polarization intensity value of each oriented fiber under the current electric field by combining the dielectric constant of different oriented fiber groups, thereby obtaining the polarization intensity distribution of the different oriented fibers.

[0046] The initial polarization intensity value is a theoretical value calculated based on the measured electric field strength and the polarizability of the supercooled medium, without considering the influence of the fiber bundle on the electric field distribution. During correction, the initial polarization intensity value is multiplied by the adjustment coefficient of the corresponding region. The orientation of the fiber bundle affects its equivalent dielectric constant: when the fiber bundle is parallel to the electric field direction, the axial dielectric constant plays a dominant role; when perpendicular, the radial dielectric constant plays a dominant role. The axial dielectric constant is usually greater than the radial dielectric constant. Based on the angle between the fiber principal axis and the electric field direction, the equivalent dielectric constant is determined by weighting the axial and radial dielectric constants. Then, the corrected polarization intensity value is decomposed according to orientation to obtain the polarization intensity distribution of each oriented fiber under the current electric field. Since the axial dielectric constant is greater than the radial dielectric constant, the polarization intensity response of parallel-oriented fibers is stronger than that of perpendicularly oriented fibers.

[0047] Step S25: Calculate the weighted average value of the polarization intensity at each measurement point to obtain the mean value of polarization intensity.

[0048] Measurement points located in densely fibrous regions represent smaller spatial areas, while those in sparsely fibrous regions represent larger spatial areas. The weighting coefficient for each measurement point is set to the reciprocal of the fiber coverage density around that point, ensuring that each measurement point's contribution to the average value is proportional to the actual spatial volume it represents. The average polarization intensity is obtained by multiplying the polarization intensity values ​​of all measurement points by their corresponding weighting coefficients, summing the results, and then dividing by the sum of all weighting coefficients. This average value reflects the average polarization response level of the entire biological tissue under the current electric field and serves as a reference benchmark for subsequently determining whether the polarization intensity in a local area is too low.

[0049] Step S26: Compare the polarization intensity of each measurement point with the average polarization intensity point by point, and mark the measurement points with polarization intensity lower than the average polarization intensity as low polarization regions.

[0050] By comparing the spatial locations of all calculated polarization intensity values ​​point by point, points with polarization intensity values ​​less than the mean are marked as low-polarization points. This can be achieved by adding identifiers to the three-dimensional spatial data structure. Low-polarization points are mainly clustered in the interstitial regions around fiber bundles with large angles to the electric field direction. Due to the high dielectric constant of the fiber material inside the fiber bundle, even with unfavorable fiber orientation, its polarization intensity may still be higher than the average level. Therefore, the distribution characteristics of low-polarization points can indirectly reflect the spatial location of the fiber interstitial regions.

[0051] Step S27: Based on the positional relationship between the low polarization region and the three-dimensional spatial arrangement, determine that the low polarization region located between the fiber bundles is the gap region with low energy storage.

[0052] For any low-polarity point, calculate its shortest distance to the central axis of all fiber bundles. If this distance is greater than the average radius of the fiber bundle, the point is determined to be located in the gap between fiber bundles. Low-polarity points located in the gaps between fiber bundles are classified as low-energy-storage gap regions, which are elongated or irregular in shape and enclosed by the surfaces of adjacent fiber bundles. The diameter of muscle tissue fiber bundles is typically 0.1 mm to 1 mm, and the gap width between fiber bundles is several hundred micrometers. These regions have low energy storage and are more likely to form ice crystal nuclei after the electric field is removed. If the ice crystal nuclei grow disorderly, they will compress the surrounding fiber bundles. Therefore, identifying and controlling the energy storage distribution in these regions is key to achieving high-quality cryopreservation.

[0053] Step S28: Calculate the absolute value of the difference between the polarization intensity at each point in the gap region with low energy storage and the average value of the polarization intensity to obtain the energy storage difference value.

[0054] The energy storage difference value quantitatively describes the degree of energy loss in the gap region relative to the overall average level; the larger the absolute value of the difference, the more severe the loss. Locations with large energy storage difference values ​​usually correspond to the regions with the largest angle between the fiber orientation and the electric field direction. By marking the energy storage difference values ​​at each point on spatial coordinates, a spatial distribution map of the energy storage difference values ​​can be drawn, which intuitively shows the severity and distribution characteristics of the energy storage loss, providing a quantitative basis for subsequent electric field adjustments.

[0055] Step S29: Use gradient change detection method to identify the abrupt boundary of polarization intensity in the polarization intensity distribution, determine the high polarization intensity region inside the abrupt boundary as the fiber interior, and determine the low polarization intensity region outside the abrupt boundary as the fiber gap; calculate the average value of the polarization intensity of the measurement points inside the fiber and the fiber gap respectively to obtain the energy storage value inside the fiber and the energy storage value in the fiber gap.

[0056] For each spatial location, the ratio of the difference in polarization intensity between it and its neighboring points along the three coordinate axes to the distance is calculated. The square root of the sum of the squares of the gradient components in the three directions is the gradient amplitude at that point. At the interface between the fiber bundle and the gap, the polarization intensity changes significantly over a short distance, and the gradient amplitude peaks. Locations where the gradient amplitude exceeds a preset gradient threshold are marked as boundary points. The boundary surface formed by consecutive boundary points divides the space into two regions: the inner region is the fiber interior, and the outer region is the fiber gap. The preset gradient threshold is set to 0.5 millijoules per cubic centimeter per millimeter, determined based on the statistical results of the measured gradient distribution of polarization intensity at the fiber-gap interface.

[0057] The arithmetic mean of the polarization intensities at all measurement points inside the fiber and in the interfiber space was taken, and recorded as the energy storage value inside the fiber and the energy storage value in the interfiber space. Taking a beef sample as an example, there were a total of 120 measurement points inside the fiber, with a total polarization intensity of 384 mJ / cm³ and an energy storage value of 3.2 mJ / cm³; there were a total of 200 measurement points in the interfiber space, with a total polarization intensity of 520 mJ / cm³ and an energy storage value of 2.6 mJ / cm³.

[0058] Step S3: Determine the deviation angle between the fiber orientation of the gap region with low energy storage and the direction of the initial electric field, and adjust the electric field direction according to the deviation angle to obtain the adjusted polarization intensity distribution.

[0059] First, spatial clustering is performed on the set of coordinate points in the gap regions with low energy storage. Density clustering is used to divide the set of coordinate points into several spatially continuous gap region blocks, each representing an interconnected gap region. The local arrangement structure of the fiber bundles around each gap region block is extracted as the spatial object for subsequent deviation angle calculations. Compared with the fiber arrangement structure of the overall organization, the local arrangement structure has a more defined directional orientation.

[0060] Step S31: Extract the main direction vector of fiber arrangement in the gap region with low energy storage, calculate the angle between the main direction vector and the direction vector of the initial electric field direction to obtain the deviation angle, and determine the electric field rotation angle based on the deviation angle.

[0061] Principal component analysis (PCA) was used to extract the principal direction vectors of the fiber bundles surrounding the interstitial region. A sample matrix was constructed using the principal axis direction vectors of each fiber bundle as samples. Eigenvalue decomposition was performed on the covariance matrix of the sample matrix; the eigenvector corresponding to the largest eigenvalue was identified as the principal direction vector, reflecting the most significant trend in the overall orientation of the surrounding fiber bundles. The angle between the principal direction vector and the initial electric field direction vector was used as the deviation angle. The electric field rotation angle was set to 70% to 90% of the deviation angle to accommodate the polarization requirements of other regions; this proportion was determined based on debugging test data from multi-region polarization equalization.

[0062] In one embodiment, there are multiple gap regions with low energy storage within the biological tissue, with deviation angles of 40°, 60°, and 80°, respectively. These regions are grouped according to similar deviation angles, with the electric field rotation angles of the three groups set to 35°, 50°, and 70°, respectively. The electric field rotation of each group is performed sequentially over time to avoid mutual interference.

[0063] Step S32: Adjust the phase difference of each electrode in the electrode plate array according to the electric field rotation angle. The electrode plate array adopts a multi-phase power supply method. By adjusting the phase relationship between each phase, the electric field direction is rotated to be parallel to the fiber direction of the gap region with low energy storage, and the adjusted electric field configuration parameters are obtained.

[0064] Single-phase electrode power supply can only generate an electric field with a fixed direction and cannot adjust the orientation of the electric field. Multiphase power supply, by applying AC voltages with specific phase differences to different electrode plates, allows the electric field components generated by each electrode plate to be synthesized in space into a composite electric field with controllable direction. Taking a four-phase electrode power supply as an example, the four sets of electrode plates are arranged along orthogonal directions in three-dimensional space. When the voltage phases of the four sets of electrode plates are 0°, 90°, 180°, and 270°, respectively, the composite electric field rotates in a specific direction. The control system, based on the three-dimensional coordinate components of the target electric field direction, reverse-engineers the voltage amplitude, phase angle, frequency, and application duration of each electrode plate, forming the adjusted electric field configuration parameters. These parameters are then converted into drive signals by the signal generation module and output to the power amplifier to form the actual electric field output. The switching of the electric field direction is achieved through a step adjustment of the voltage phase of each phase. A single switch is completed within 5 to 20 milliseconds, matching the millisecond-level polarization response time of the supercooled medium.

[0065] Step S33: Apply an electric field to the gap region with low energy storage using the adjusted electric field configuration parameters to keep the water molecules in the supercooled medium in an orderly arrangement, thereby obtaining the adjusted polarization intensity distribution.

[0066] The control system determines the electrode plates involved in the electric field regulation of the gap region based on its spatial coordinates. Electrode plates closer to the gap region have the greatest impact on the electric field distribution, and their configuration parameters directly determine the electric field state of the gap region. Electrode plates farther away participate with lower voltages, serving as auxiliary plates and preventing edge effects. Water molecules in the supercooled medium are polar molecules; under the influence of the electric field, their dipole moments align along the direction of the electric field. As the electric field direction changes, the dipole moments rotate accordingly, forming an ordered dynamic arrangement. A sensor array collects the electric field intensity values ​​at each measurement point at fixed time intervals and transmits them to the control system in real time. The control system compares the current polarization intensity distribution with the target value; if a deviation exists, it automatically adjusts the voltage parameters of the electrode plates, forming a closed-loop control. In one implementation, polarization intensity data is collected once every millisecond. The time series is processed by moving average to obtain a smooth curve. The slope of the curve reflects the polarization establishment speed, and the steady-state value reflects the final polarization level.

[0067] Step S34: Control the temperature of the gap region with low energy storage to be below the freezing point and above the nucleation temperature, so that the subcooled medium is kept in a subcooled liquid state to store cold energy.

[0068] Temperature control is achieved through the refrigeration system of the quick-freezing device. This system employs multi-stage compression refrigeration technology, with temperature sensors distributed across multiple locations within the device to monitor the temperature in real time. The control system adjusts the refrigeration power based on temperature feedback. The target temperature is set between -5℃ and -15℃, with the specific value determined based on the type of biological tissue and the characteristics of the supercooled medium. The nucleation temperature is the critical temperature at which the supercooled liquid begins to spontaneously form ice crystal nuclei; its value depends on the purity of the liquid, external field conditions, and the characteristics of the container walls. After water molecules form an ordered arrangement under the influence of an electric field, the nucleation temperature can be lowered to below -20℃, satisfying the window condition of a temperature below the freezing point and above the nucleation temperature. The supercooled liquid state stores energy corresponding to the heat of freezing compared to the solid state at the same temperature; extending the duration of the supercooled liquid state allows for the storage of more cold energy.

[0069] In one embodiment, a fresh pork sample was immersed in a supercooled medium for 30 minutes to allow for full penetration. After applying an electric field and lowering the temperature inside the device to -10°C, the supercooled medium inside the pork remained liquid for more than 15 minutes; under the same conditions, the control group without an applied electric field maintained the supercooled liquid state for less than 2 minutes. This comparison demonstrates that the regulating effect of an electric field on the ordered arrangement of water molecules can effectively prolong the supercooled state.

[0070] Step S4: Generate an electric field switching cycle according to the adjusted polarization intensity distribution, and switch the electric field direction according to the electric field switching cycle in a time-division manner to form a superimposed spatial electric field covering different fiber orientations, so that the supercooled medium in each gap region maintains orderly polarization and stores cold energy.

[0071] A single-direction electric field cannot simultaneously satisfy the polarization requirements of all gap regions. By setting an electric field switching cycle, the electric field can be cyclically switched between multiple different directions, which can sequentially cover fiber regions with various orientations, thus achieving overall balanced polarization.

[0072] Step S41: Based on the adjusted polarization intensity distribution, calculate the time required for the polarization intensity of different regions to reach stability, and take the maximum value of the stabilization time of each region as the basic period length.

[0073] Polarization establishment requires a certain amount of time, determined by the rotational inertia of polar molecules and the viscous properties of the supercooled medium. The polarization intensity increases exponentially with time. When the polarization intensity of a region reaches more than 95% of the final steady-state value and remains stable for more than 5 milliseconds, the region is considered to have reached a stable state. This stability criterion is determined based on the statistical results of the measured polarization response curves. The time elapsed from the application of the electric field to reaching a stable state is recorded as the stabilization time for that region. Molecular activity is restricted in densely fiberd regions, resulting in longer stabilization times; sparsely fiberd regions have shorter stabilization times. The maximum stabilization time for each region is taken as the base period length, ensuring that all regions have sufficient time to reach a stable polarization state within each period. If the base period is too short, some regions will not have enough time to complete polarization establishment, and the original polarization state will be broken after switching; if it is too long, the processing efficiency will decrease. The base period length is typically in the range of tens to hundreds of milliseconds, with the specific value determined based on actual measurement results.

[0074] Step S42: Set multiple switching time points within the basic cycle length to generate the electric field switching cycle that includes the switching time and duration.

[0075] The switching time points are set according to the distribution characteristics of different fiber orientations. The duration of each segment is weighted according to the proportion of fibers of each orientation in the tissue, with orientations having a larger proportion receiving a longer duration. For example, in a biological tissue, the proportions of the three main fiber orientations are 50%, 30%, and 20%, respectively, and the base cycle length is 100 milliseconds. The three switching time points are set at 0 milliseconds, 50 milliseconds, and 80 milliseconds, with corresponding durations of 50 milliseconds, 30 milliseconds, and 20 milliseconds, respectively. The complete parameters of the electric field switching cycle include the start time, the sequence of switching time points, the duration of each segment, and the sequence of electric field configuration parameters, which are strictly executed by the timing generation module of the control system. During the switching process, the electric field direction smoothly transitions from one orientation to the next, avoiding polarization oscillations caused by abrupt changes.

[0076] Step S43: Control the electrode plate array according to the electric field switching cycle, record the energy storage value inside the fiber and the energy storage value between the fibers at each switching moment, and calculate the difference between the two to form a difference sequence.

[0077] If an electric field switching cycle contains 5 switching moments, then 5 sets of energy storage values ​​are obtained for each cycle. Subtracting the energy storage value between fibers from the energy storage value within the fiber gives the energy storage difference at each switching moment. These differences are then arranged chronologically to form a difference sequence. A consistently positive and large difference indicates insufficient polarization in the fiber gap region; a consistently negative difference may be due to excessive compensation from electric field rotation. Ideally, the difference should remain within a small positive range, indicating a basic balance of energy storage inside and outside the fiber.

[0078] Step S44: Perform time-cumulative averaging on the difference sequence to obtain the difference change trend, calculate the ratio of the energy storage value inside the fiber to the energy storage value between the fibers based on the difference change trend, evaluate the degree of energy storage balance, and correct the electric field switching cycle based on the degree of energy storage balance.

[0079] Each value in the cumulative average sequence takes into account historical data, and its curve over time represents the trend of the difference. A downward trend in the curve indicates that the energy storage difference is gradually decreasing, and stabilization indicates that the system has entered a state of equilibrium; an upward trend or fluctuations indicate that the current electric field switching cycle parameters need to be adjusted. The ratio of the energy storage value inside the fiber to the energy storage value between the fiber gaps is used as the degree of energy storage balance. The closer the ratio is to 1, the more balanced the energy storage inside and outside the fiber; a ratio much greater than 1 indicates that the energy storage inside the fiber is too high. The target range for the degree of energy storage balance is set to 1.1 to 1.3, determined based on the data from the quick-freezing quality comparison test. When the target range is exceeded, the control system automatically adjusts the switching time point, the duration of each segment, and the direction of the electric field until it returns to the target range. If the target range is not reached after 20 corrections, the correction is terminated, and the electric field switching cycle with the closest energy storage balance to the target range among all corrections is selected as the final solution.

[0080] The total energy storage value is obtained by summing the energy storage values ​​within the fibers and those between the fibers. This total energy storage value is then converted to the total cold storage value, with the conversion factor related to the specific heat capacity, latent heat of phase change, and temperature difference of the supercooled medium. A larger total cold storage value allows for a longer period of time that the supercooled state can be maintained after the electric field is removed. In one embodiment, a beef sample was quick-frozen, and the measured energy storage value within the fibers was 3.2 mJ / cm³, the energy storage value between the fibers was 2.6 mJ / cm³, the energy storage uniformity was 1.23, and the total cold storage value was calculated to be 5.8 mJ / cm³. This cold storage capacity can support the sample in a supercooled liquid state at -8°C for more than 10 minutes, providing a sufficient time window for subsequent directional ice crystal growth.

[0081] Step S5: Identify the orientation angle of ice crystal growth in each region, determine the deviation of the ice crystal growth angle between the orientation angle and the fiber gap direction, adjust the electric field switching cycle according to the ice crystal growth angle deviation, so that the supercooled medium is uniformly polarized in the fiber gap, and control the ice crystals to grow in a directional manner along the fiber gap direction.

[0082] When the ice crystal growth direction is consistent with the fiber alignment direction, the ice crystal extends within the fiber gaps without damaging the fiber structure. However, if it forms a large angle with the fiber alignment direction, the ice crystal will laterally cut the fibers, causing structural damage. Therefore, it is necessary to accurately identify and control the orientation angle of ice crystal growth.

[0083] Step S51: Remove the electric field to cause the supercooled medium to crystallize instantaneously, and record the polarization intensity value and spatial coordinates of each region at the moment of crystallization trigger.

[0084] When the energy storage balance is within the target range and the total stored cold energy meets the preset cold energy threshold, the crystallization triggering stage begins. The preset cold energy threshold is set at 4.0 millijoules per cubic centimeter, calculated based on the cold energy required to maintain the target sample in a supercooled liquid state for 10 minutes at -8°C. The electric field is removed by synchronously shutting off the power supply to all electrode plates via the control system. The removal process is completed within milliseconds, avoiding gradual changes in polarization due to electric field decay. After the electric field is removed, the electric field energy stored in the supercooled medium is rapidly released, triggering a phase transition of water molecules from the supercooled liquid state to the solid state. The entire structure crystallizes within seconds. Simultaneously with the removal of the electric field, the control system initiates high-speed data acquisition, recording the residual polarization intensity and spatial coordinates at each measurement point as the primary basis for analyzing the ice crystal growth direction. The polarization intensity at the crystallization triggering moment reflects the molecular orientation arrangement state before crystallization in each region, directly affecting the lattice orientation during ice crystal formation. In regions with higher polarization, the molecular arrangement is more ordered, and ice crystals tend to grow along the direction of molecular arrangement; in regions with lower polarization, the direction of ice crystal growth is more random.

[0085] Step S52: Calculate the ratio of the polarization intensity difference to the distance between adjacent measurement points based on the polarization intensity value and spatial coordinates to obtain the magnitude of the polarization intensity gradient at each point, and determine the gradient direction vector through the components of the gradient on the three-dimensional coordinate axes.

[0086] For any given measurement point, select its six nearest neighbor measurement points along its six orthogonal directions. Divide the difference in polarization intensity in each direction by the Euclidean distance between the two points to obtain the gradient components on the three coordinate axes. These three components are combined sequentially to form the gradient direction vector, and the square root of the sum of the squares of the three components is the gradient magnitude. Near the fiber bundle boundary, the gradient magnitude reaches its peak due to the significant difference in polarization intensity between the fibers and the interstitial spaces. Inside the fibers or interstitial spaces, far from the boundary, the change in polarization intensity is gradual, and the gradient magnitude is relatively small. During crystallization, water molecules tend to combine sequentially along the gradient direction to form ice crystal structures; the gradient direction can be used to characterize the growth direction of ice crystals.

[0087] Step S53: Calculate the angle between the gradient direction vector and the fiber arrangement direction at the corresponding position to identify the orientation angle of ice crystal growth in each region.

[0088] The gradient direction vector is mapped onto a local fiber spatial coordinate system, with the principal axis of the dominant fiber bundle as one axis. In regions with complex fiber arrangements, ice crystal growth may be influenced by multiple fiber bundles, requiring comprehensive identification based on the three-dimensional spatial arrangement data of the fibers. The orientation angle of ice crystal growth is defined as the angle between the ice crystal growth direction and the fiber long axis, ranging from 0° to 90°. When the orientation angle is small, ice crystals grow along the fiber to form columnar crystals; when the orientation angle is large, ice crystals grow laterally, easily damaging the fiber structure; when the orientation angle is in the middle, ice crystals grow obliquely, with the degree of damage falling between the two. Different regions of the same tissue may exhibit different orientation angles, requiring traversal of all regions to obtain spatial distribution data of the orientation angles.

[0089] Step S54: Compare the orientation angle with the growth direction along the fiber gap point by point, calculate the angle difference as the ice crystal growth angle deviation, and statistically analyze the spatial distribution of the deviation points to obtain the angle deviation distribution map.

[0090] For any spatial location, the target growth direction is parallel to the main axis of the surrounding fiber bundles. The difference between the actual orientation angle and the target angle, and the absolute value of this difference, yields the ice crystal growth angle deviation at that point, ranging from 0° to 90°. A deviation value of 0 indicates that the actual growth direction perfectly meets the target requirements. The deviation values ​​at each point are plotted at their spatial coordinates, forming an angle deviation distribution map. Deviations typically exhibit regional clustering characteristics; high deviation values ​​correspond to locations with complex fiber arrangements or insufficient electric field, providing spatial positioning data for targeted adjustments.

[0091] Step S55: Extract the electric field switching cycle parameters corresponding to the deviation region according to the angle deviation distribution map, and change the polarization establishment rate of the deviation region by adjusting the switching time interval to generate the adjusted electric field switching cycle.

[0092] Spatial regions with deviations exceeding a preset deviation threshold are identified as deviation areas. The preset deviation threshold is set between 10° and 20°, determined based on comparative experimental data on the degree of tissue damage caused by ice crystal growth direction. Deviations below the threshold are within an acceptable range and do not require specific adjustment. The control system maintains complete time-series records of electric field parameters. By querying the historical electric field parameters based on the spatial coordinates of the deviation area, the problematic time period causing the deviation is located. For the problematic time period, the switching interval is shortened to accelerate the polarization establishment rate, and an intermediate transition electric field direction is added within this period to make the electric field direction change smoother. The adjusted switching interval and the transition electric field direction together constitute the adjusted electric field switching cycle. The new switching cycle ensures that the polarization establishment process in the deviation area meets the target requirements, the polarization intensity gradient direction gradually approaches the fiber alignment direction, and the ice crystal growth orientation angle subsequently approaches 0.

[0093] Step S56: Apply the electric field again using the adjusted electric field switching cycle, monitor the polarization intensity value at each point in the fiber gap, calculate the ratio of the standard deviation to the average value of the polarization intensity, and when the ratio of the standard deviation to the average value is lower than the preset uniformity threshold, determine that the supercooled medium is uniformly polarized in the fiber gap, and control the ice crystals to grow directionally along the fiber gap direction.

[0094] The preset uniformity threshold was set to 10%, determined based on data from a quick-freezing quality comparison test. The test showed that when the ratio of the standard deviation to the mean was less than 10%, the thawed juice loss rate of the sample remained stable within 5%. The electrode array was re-applied with an electric field according to the adjusted timing parameters, and the sensor array synchronously monitored the polarization intensity at each measurement point in the fiber gaps, calculating its arithmetic mean and standard deviation. A smaller standard deviation indicates a smaller difference in polarization intensity at each point and a more uniform polarization distribution. Under uniform polarization, water molecules at each point in the fiber gaps are aligned in the same direction, and ice crystals extend continuously along the fiber gap direction, forming columnar crystals along the fiber direction. This avoids lateral compression of the fiber structure, maximizing the protection of the integrity of the biological tissue. Frozen tissues can better recover their original taste, color, and juice retention capacity upon thawing.

[0095] In one embodiment, the above method is applied to the quick-freezing processing of tuna chunks. After being stored at -20°C for 3 months and then thawed, the thawing juice loss rate is only 3%, far lower than the 15% of traditional quick-freezing methods, and the color, texture, elasticity, and taste are close to those of fresh tuna. In another embodiment, this method is applied to the quick-freezing preservation of vegetable cell tissues. By controlling the growth of ice crystals along the cell wall direction to prevent ice crystals from penetrating the cell wall and causing cell rupture, the thawed vegetables retain a crisp and tender texture and nutritional content close to that of fresh tuna.

[0096] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the concept of this application. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. A method for rapid freezing of a superimposed spatial electric field in a superimposed spatial electric field, characterized in that, include: The three-dimensional spatial arrangement of biological tissue fibers immersed in a supercooled medium is obtained. The fiber arrangement angle and fiber coverage density are identified based on the three-dimensional spatial arrangement. The preliminary electric field direction and polarization intensity of each region of the superimposed spatial electric field are collected. Based on the fiber arrangement angle, the fiber coverage density, and the polarization intensity of each region, the polarization intensity distribution of fibers with different orientations is determined, and the regions with low polarization intensity in the polarization intensity distribution are identified as gap regions with low energy storage. Determine the deviation angle between the fiber orientation of the gap region with low energy storage and the direction of the initial electric field, and adjust the electric field direction according to the deviation angle to obtain the adjusted polarization intensity distribution; The electric field switching cycle is generated according to the adjusted polarization intensity distribution. The electric field direction is switched in time according to the electric field switching cycle to form a superimposed spatial electric field covering different fiber orientations, so that the supercooled medium in each gap region is kept in an orderly polarization and stores cold energy. Identify the orientation angle of ice crystal growth in each region, determine the deviation of the ice crystal growth angle between the orientation angle and the fiber gap direction, adjust the electric field switching cycle according to the ice crystal growth angle deviation, so that the supercooled medium is uniformly polarized in the fiber gap, and control the ice crystal to grow in a directional manner along the fiber gap direction.

2. The method as described in claim 1, characterized in that, The process of obtaining the three-dimensional spatial arrangement of biological tissue fibers immersed in a supercooled medium, identifying the fiber arrangement angle and fiber coverage density based on the three-dimensional spatial arrangement, and acquiring the preliminary electric field direction and polarization intensity of the superimposed spatial electric field in each region includes: An ultrasonic scanner was used to scan the biological tissue immersed in the supercooled medium layer by layer to obtain cross-sectional image data. The fiber contour coordinates in the cross-sectional image data are extracted by an image recognition algorithm. The three-dimensional spatial trajectory of the fiber bundle is constructed according to the spatial connection relationship of the corresponding fiber contour coordinates between adjacent layers to obtain the three-dimensional spatial arrangement. For the three-dimensional spatial arrangement, the angle between the central axes of adjacent fiber bundles is calculated to obtain the fiber arrangement angle, and the number of fiber bundles in each fiber group per unit volume is counted to obtain the fiber coverage density. An array of electrode plates is arranged in the quick-freezing device according to the fiber coverage density, a uniform electric field is applied, the direction of the uniform electric field is taken as the initial electric field direction, and a sensor probe is used to measure the local polarization intensity in different fiber group regions to obtain the polarization intensity of each region.

3. The method as described in claim 1, characterized in that, The step of determining the polarization intensity distribution of fibers with different orientations based on the fiber arrangement angle, the fiber coverage density, and the polarization intensity of each region includes: Obtain the principal axis direction of each fiber bundle in the three-dimensional spatial arrangement, and calculate the angle between the principal axis direction and the initial electric field direction; The unidirectional electric field coverage rate is obtained by calculating the ratio of the number of fiber bundles with included angles less than a preset angle threshold to the total number of fiber bundles. Based on the unidirectional electric field coverage rate, fiber coverage density data of uncovered fiber areas are extracted, and polarization intensity adjustment coefficients for different areas are obtained through function mapping. The initial polarization intensity value of each region is corrected by the polarization intensity adjustment coefficient, and the polarization intensity value of each oriented fiber under the current electric field is calculated by combining the dielectric constant of different oriented fiber groups, so as to obtain the polarization intensity distribution of the different oriented fibers.

4. The method as described in claim 1, characterized in that, The step of identifying regions with low polarization intensity in the polarization intensity distribution as gap regions with low energy storage includes: The weighted average value of the polarization intensity at each measurement point is calculated to obtain the mean value of the polarization intensity; The polarization intensity at each measurement point is compared with the average polarization intensity point by point, and the measurement points with polarization intensity lower than the average polarization intensity point are marked as low polarization regions. Based on the positional relationship between the low polarization region and the three-dimensional spatial arrangement, the low polarization region located between fiber bundles is determined to be the gap region with low energy storage. The absolute value of the difference between the polarization intensity at each point in the gap region with low energy storage and the mean value of the polarization intensity is calculated to obtain the energy storage difference value.

5. The method as described in claim 4, characterized in that, Also includes: The gradient change detection method is used to identify the abrupt boundary of polarization intensity in the polarization intensity distribution. The high polarization intensity region inside the abrupt boundary is determined to be the fiber interior, and the low polarization intensity region outside the abrupt boundary is determined to be the fiber gap. The average value of the polarization intensity at the measurement points inside the fiber and in the fiber gap is calculated respectively to obtain the energy storage value inside the fiber and the energy storage value in the fiber gap.

6. The method as described in claim 1, characterized in that, The step of determining the deviation angle between the fiber orientation in the gap region with low energy storage and the initial electric field direction, and adjusting the electric field direction according to the deviation angle to obtain the adjusted polarization intensity distribution includes: Extract the principal direction vector of the fiber arrangement in the gap region where the energy storage is low, calculate the angle between the principal direction vector and the direction vector of the initial electric field direction to obtain the deviation angle, and determine the electric field rotation angle based on the deviation angle. The phase difference of each electrode in the electrode plate array is adjusted according to the electric field rotation angle. The electrode plate array adopts a multi-phase power supply method. By adjusting the phase relationship between each phase, the electric field direction is rotated to be parallel to the fiber direction of the gap region with low energy storage, and the adjusted electric field configuration parameters are obtained. An electric field is applied to the gap region with low energy storage using the adjusted electric field configuration parameters, so that the water molecules in the supercooled medium are kept in an orderly arrangement, and the adjusted polarization intensity distribution is obtained. The temperature of the gap region with low energy storage is controlled to be below the freezing point and above the nucleation temperature, so that the subcooled medium is kept in a subcooled liquid state to store cold energy.

7. The method as described in claim 5, characterized in that, The step of generating the electric field switching period based on the adjusted polarization intensity distribution includes: Based on the adjusted polarization intensity distribution, the time required for the polarization intensity in different regions to reach stability is calculated, and the maximum value of the stability time in each region is taken as the basic period length. Multiple switching time points are set within the basic cycle length to generate the electric field switching cycle, which includes the switching time and duration. The electrode plate array is controlled according to the electric field switching cycle. At each switching moment, the energy storage value inside the fiber and the energy storage value between the fibers are recorded, and the difference between the two is calculated to form a difference sequence. The difference sequence is cumulatively averaged over time to obtain the difference change trend. The ratio of the energy storage value inside the fiber to the energy storage value between the fibers is calculated based on the difference change trend to assess the degree of energy storage balance. The electric field switching cycle is then corrected based on the degree of energy storage balance.

8. The method as described in claim 1, characterized in that, The process of identifying the orientation angle of ice crystal growth in each region, determining the deviation of the ice crystal growth angle between the orientation angle and the fiber gap direction, and adjusting the electric field switching cycle according to the ice crystal growth angle deviation to control the directional growth of ice crystals along the fiber gap direction includes: Remove the electric field to cause the supercooled medium to crystallize instantaneously, and record the polarization intensity value and spatial coordinates of each region at the moment of crystallization triggering. The polarization intensity difference between adjacent measurement points is calculated based on the polarization intensity value and spatial coordinates, and the distance is used to obtain the polarization intensity gradient magnitude at each point. The gradient direction vector is determined by the components of the gradient on the three-dimensional coordinate axes. Calculate the angle between the gradient direction vector and the fiber arrangement direction at the corresponding position to identify the orientation angle of ice crystal growth in each region; The orientation angle is compared point by point with the growth direction along the fiber gap, and the angle difference is calculated as the ice crystal growth angle deviation. The spatial distribution of the deviation points is statistically analyzed to obtain the angle deviation distribution map. Based on the angle deviation distribution map, extract the electric field switching period parameters corresponding to the deviation region, and change the polarization establishment rate of the deviation region by adjusting the switching time interval to generate the adjusted electric field switching period. The electric field is reapplied using the adjusted electric field switching cycle. The polarization intensity value at each point in the fiber gap is monitored. The ratio of the standard deviation to the average value of the polarization intensity is calculated. When the ratio of the standard deviation to the average value is lower than the preset uniformity threshold, it is determined that the supercooled medium is uniformly polarized in the fiber gap, and the ice crystals are controlled to grow directionally along the fiber gap direction.

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