Helium superfluid transition point measurement method and device based on microwave response characteristic iteration determination

Abstract

The application provides a helium superfluid transition point measurement method and device based on microwave response feature iterative determination, and relates to the technical field of low temperature measurement. The method comprises the following steps: adjusting the state variable of the measured liquid helium to cross the estimated superfluid transition interval, and obtaining first microwave response data; constructing a microwave feature response curve based on the first microwave response data, and determining a candidate transition interval; performing local encryption measurement in the candidate transition interval, and determining a candidate transition point according to second microwave response data; performing neighborhood verification around the candidate transition point, confirming or updating the candidate transition point according to the verification result, and iteratively performing local encryption measurement and neighborhood verification until the helium superfluid transition point is determined. The application aims to improve the problem of low helium superfluid transition point measurement accuracy and stability in the prior art.

Description

Technical Field

[0001] This application relates to the field of cryogenic measurement technology, and in particular to a method and apparatus for measuring the helium superfluid transition point based on iterative determination of microwave response characteristics. Background Technology

[0002] Cryogenic measurement technology is widely used in cryogenic temperature scale reproduction, superconducting device testing, quantum precision measurement, calibration of cryogenic engineering devices, and fundamental physical property research. Liquid helium provides a stable cryogenic environment for cryogenic experiments and cryogenic engineering devices. When the temperature or pressure of liquid helium changes to a specific range, liquid helium can transition between a normal fluid state and a superfluid state; the corresponding transition point is usually called the helium-superfluid transition point. The helium-superfluid transition point can not only characterize the state of liquid helium but also serve as an important reference for cryogenic temperature scale reproduction, cryogenic measurement device calibration, and identification of the operating status of superfluid helium systems. Because the helium-superfluid transition occurs within a narrow temperature or pressure range, and the dielectric properties, density fluctuations, viscosity, and thermal transfer characteristics of liquid helium near the transition range change rapidly, the measurement process is easily affected by external heat leakage, pressure fluctuations, local temperature gradients, and measurement link response hysteresis. This places high demands on the resolution, stability, and repeatability of the transition point measurement.

[0003] In existing technologies, the helium superfluid transition point can be determined by measuring vapor pressure, directly measuring temperature, or performing curve analysis on the response data of liquid helium when it crosses the estimated transition range, based on abrupt changes, extreme values, or inflection points of physical quantities. However, these methods are easily affected by measurement noise, system drift, and dynamic response hysteresis, resulting in insufficient accuracy and stability in the transition point measurement. Summary of the Invention

[0004] The embodiments disclosed in this application provide a method and apparatus for measuring the helium superfluid transition point based on iterative determination of microwave response characteristics, aiming to improve the above-mentioned problems.

[0005] The embodiments of this application adopt the following technical solutions: Firstly, a method for measuring the helium superfluid transition point based on iterative determination of microwave response characteristics is provided, the method comprising: The state variables of the liquid helium to be tested are adjusted so that the measurement state of the liquid helium to be tested crosses the predicted superfluid transition range, and the first microwave response data during the change of state variables are obtained. Microwave characteristic response curves are constructed based on the first microwave response data, and candidate transition intervals are determined based on the changing characteristics of the microwave characteristic response curves. Within the candidate transition interval, the state variables are locally encrypted and adjusted to obtain the second microwave response data, and the candidate transition point is determined based on the second microwave response data. Neighborhood verification measurements are performed around candidate transition points to obtain verification response data, and the verification results of candidate transition points are determined based on the verification response data. Based on the verification results, candidate transition points are confirmed or updated, and local encryption adjustment and neighborhood verification measurements are iteratively performed to determine the helium superfluid transition point.

[0006] In one possible implementation of the first aspect, a microwave characteristic response curve is constructed based on the first microwave response data, and a candidate transition interval is determined according to the changing characteristics of the microwave characteristic response curve, including: The first microwave response data is correlated with the corresponding state variable values ​​to obtain the initial response curve of the microwave response parameters as the state variables change. The initial response curve is corrected and its characteristics are transformed to obtain the distribution of response characteristics as a function of state variables; Candidate transition intervals are determined based on the range of state variables that meet the preset transition criteria according to the response characteristics.

[0007] In one possible implementation of the first aspect, local encryption adjustment of the state variables within the candidate transition interval is performed to obtain second microwave response data, including: The local scan step size is determined based on the width of the candidate transition interval and the acquisition resolution of the first microwave response data. The state variables are adjusted within the candidate transition interval according to the local scanning step size, and microwave response data is collected after the microwave response corresponding to each state variable value meets the stability condition to obtain the second microwave response data.

[0008] In one possible implementation of the first aspect, determining candidate transition points based on second microwave response data includes: Construct local characteristic response curves corresponding to candidate transition intervals based on the second microwave response data; Based on the local change characteristics of the local characteristic response curve at different state variable values, determine the intensity of the transition characteristics corresponding to each state variable value; The state variable values ​​whose transformation characteristic intensity meets the preset extreme value condition are determined as candidate transformation points.

[0009] In one possible implementation of the first aspect, neighborhood verification measurements are performed around the candidate transition point to obtain verification response data, including: The neighborhood verification range is determined based on the candidate transition points, and multiple verification state variable values ​​are determined within the neighborhood verification range; The state variables of the liquid helium to be tested are adjusted to the candidate transition point and the values ​​of each verification state variable, respectively, and the corresponding verification response data are obtained. The verification results are determined based on the differences in the intensity of transition characteristics between candidate transition points and the values ​​of each verification state variable, as well as the relationship between the response changes on both sides of the candidate transition point.

[0010] In one possible implementation of the first aspect, updating candidate transition points based on verification results includes: If the candidate transition point fails the verification, the verification response data is incorporated into the second microwave response data to update the local characteristic response curve. The feature deviation of the candidate transition point is determined based on the updated local feature response curve, and the candidate transition point and candidate transition interval are updated based on the feature deviation. Based on the updated candidate transition interval, local encryption adjustment and neighborhood verification measurement are performed again until the difference between two adjacent candidate transition points satisfies the convergence condition.

[0011] In one possible implementation of the first aspect, the method further includes: Local encryption adjustment and neighborhood verification measurement are repeatedly performed around candidate transition points that meet the preset judgment conditions to obtain multiple transition point measurement results; The helium superfluid transition point is determined based on multiple transition point measurements, and the measurement repeatability is determined based on the dispersion among the multiple transition point measurements.

[0012] In one possible implementation of the first aspect, the second microwave response data includes response data corresponding to a plurality of microwave response parameters; Determine the transition characteristic strength corresponding to each state variable value, including: Response features are extracted from the response data corresponding to each microwave response parameter, and the extracted response features are normalized. The normalized response features are weighted and fused to obtain joint response features; The intensity of the transition characteristics corresponding to the values ​​of each state variable is determined based on the changes in the joint response characteristics with the state variables.

[0013] In one possible implementation of the first aspect, the state variable includes temperature or pressure, and the adjustment method of the state variable includes continuous adjustment, step adjustment, or reciprocating adjustment. When using reciprocating adjustment, the transition point measurement results are determined based on the microwave response data corresponding to the two opposite adjustment directions, and the transition point measurement results corresponding to the two adjustment directions are fused to obtain candidate transition points after hysteresis compensation.

[0014] In one possible implementation of the first aspect, the microwave response parameters include at least one of resonant frequency, quality factor, phase, group delay, reflection coefficient, transmission coefficient, and insertion loss; The correction process includes at least one of the following: smoothing, filtering, baseline subtraction, drift compensation, and reference channel differential processing.

[0015] The helium superfluid transition point measurement method provided in this application acquires the first microwave response data when the liquid helium under test crosses the estimated superfluid transition range, and determines the candidate transition range based on the constructed microwave characteristic response curve, thereby narrowing the range for subsequent fine measurements. By performing local densification adjustments within the candidate transition range, the measurement resolution of the microwave response characteristics near the transition point can be improved. Furthermore, by performing neighborhood verification on the candidate transition point and confirming or updating the candidate transition point based on the verification results, the data obtained during the verification process participates in subsequent iterative determination, reducing the impact of single-scan noise, response drift, and local anomalies on the determination results, thereby improving the accuracy, stability, and repeatability of helium superfluid transition point measurement.

[0016] Secondly, a helium superfluid transition point measurement device based on microwave response characteristic iterative determination is provided, the device comprising: The data acquisition module is used to adjust the state variables of the liquid helium to be tested so that the measurement state of the liquid helium to be tested crosses the predicted superfluid transition range, and to acquire the first microwave response data during the change of state variables. The interval identification module is used to construct a microwave characteristic response curve based on the first microwave response data, and to determine the candidate transition interval according to the changing characteristics of the microwave characteristic response curve. The local measurement module is used to perform localized encryption adjustment of the state variables within the candidate transition interval, acquire the second microwave response data, and determine the candidate transition point based on the second microwave response data. The verification module is used to perform neighborhood verification measurements around the candidate transition point, obtain verification response data, and determine the verification result of the candidate transition point based on the verification response data. The iterative determination module is used to confirm or update candidate transition points based on the verification results, and iteratively perform local encryption adjustment and neighborhood verification measurement to determine the helium superfluid transition point.

[0017] Thirdly, an electronic device is provided, comprising: a memory and at least one processor. The memory is communicatively connected to the processor. The memory is used to store computer program code, which includes computer instructions. When the processor executes the computer instructions, it causes the electronic device to perform the method as described in the first aspect.

[0018] Fourthly, embodiments of this application provide a computer-readable storage medium storing computer instructions. When executed by a processor, the computer instructions cause the processor to perform the method as described in the first aspect.

[0019] Understandably, the technical effects of the second to fourth aspects refer to the technical effects of the first aspect and any of its embodiments, and will not be repeated here. Attached Figure Description

[0020] Figure 1 A flowchart of one step of a method for measuring the helium superfluid transition point based on iterative determination of microwave response characteristics provided in this application embodiment; Figure 2 A second flowchart illustrating the steps of a method for measuring the helium superfluid transition point based on iterative determination of microwave response characteristics, provided in this application embodiment; Figure 3 The third step of the flowchart of the helium superfluid transition point measurement method based on microwave response characteristic iterative determination provided in the embodiments of this application; Figure 4 This is a block diagram of a helium superfluid transition point measurement device based on microwave response characteristic iterative determination, provided in an embodiment of this application. Detailed Implementation

[0021] The technical solutions in some embodiments of this application will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of this application, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments provided in this application are within the scope of protection of this application.

[0022] Unless the context otherwise requires, throughout the specification and claims, the term "comprising" is interpreted as open-ended and encompassing, meaning "including, but not limited to." In the description of the specification, terms such as "one embodiment," "some embodiments," "exemplary embodiment," "exemplary," or "some examples," etc., are intended to indicate that a particular feature, structure, material, or characteristic associated with that embodiment or example is included in at least one embodiment or example of this application. The illustrative representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, a particular feature, structure, material, or characteristic may be included in any suitable manner in any one or more embodiments or examples.

[0023] Hereinafter, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of this application, unless otherwise stated, "a plurality of" means two or more.

[0024] Cryogenic measurement technology is widely used in low-temperature physics research, cryogenic temperature scale reproduction, superconducting device testing, quantum precision measurement, and monitoring of cryogenic engineering devices. Liquid helium, with its low temperature range, chemical stability, and suitability for creating cryogenic environments, is an important working medium in cryogenic experiments and engineering. When the temperature of liquid helium drops to a specific range, it can transition from a normal fluid state to a superfluid state, exhibiting significant changes in viscosity, thermal conductivity, flow characteristics, and density fluctuations. The transition point between the normal and superfluid states is commonly referred to as the helium-superfluid transition point or the λ transition point. The helium-superfluid transition point can be used to characterize the state of liquid helium and is also an important reference for cryogenic temperature scale reproduction, cryogenic measurement device calibration, superfluid helium experiments, and the identification of the operating status of cryogenic systems.

[0025] Helium superfluid transitions typically occur within a narrow temperature or pressure range, and the physical properties near this transition range are highly sensitive to temperature or pressure changes. In actual measurements, temperature gradients, pressure fluctuations, and localized differences in heat exchange may exist within liquid helium. The measuring device may also be affected by external heat leakage, environmental disturbances, and sensor response hysteresis. Particularly when temperature or pressure changes continuously, the acquired measurement signal may be delayed relative to the actual state change of the liquid helium, leading to differences in the transition position obtained during heating and cooling processes, or pressure increases and decreases. Furthermore, the helium superfluid transition range is narrow; if the measurement step size is large, localized changes within the transition range may be missed; conversely, consistently using small step sizes over a large measurement range increases measurement time and makes the results more susceptible to long-term system drift and external disturbances.

[0026] In one feasible implementation of the related technology, the superfluid transition point of helium can be determined by measuring the liquid helium vapor pressure based on the correlation between the saturated vapor pressure and temperature of liquid helium. This method requires high accuracy and stability in pressure measurement, as static pressure of the liquid column, pressure transmission delay, and pressure fluctuations within the pipeline can all affect the measurement results. Alternatively, direct thermometer measurement, a constant-temperature platform method, or simultaneous measurement at different positions of the liquid column can be used to determine the state transition position of liquid helium by detecting changes in temperature, pressure, liquid level, or other physical quantities. However, these methods are easily affected by the thermometer installation position, sensor calibration errors, local temperature gradients, and dynamic response hysteresis. When the change in the measured signal is small or the measurement environment is disturbed, determining the transition point based solely on a sudden change in a single physical quantity can easily affect the stability and repeatability of the measurement results.

[0027] In one feasible implementation of the related technology, liquid helium can be continuously or stepwise traversed across the predicted transition range, data on the changes in measurement parameters with temperature or pressure can be collected, and the helium superfluid transition point can be determined based on the threshold position, local extrema, or inflection point of the response curve. When using microwave signals for measurement, changes in the dielectric properties, density fluctuations, and microwave transmission characteristics of liquid helium can manifest as changes in microwave response parameters such as resonant frequency, quality factor, phase, or group delay. However, the microwave measurement link itself may suffer from frequency drift, background fluctuations, and measurement noise, and local changes in the response curve caused by system drift or accidental disturbances can easily be confused with the actual phase transition characteristics of liquid helium. If the extrema, zero-crossing points, or inflection points obtained from a single scan are directly taken as the helium superfluid transition point, it is difficult to further determine whether the position is a stable phase transition response position.

[0028] Furthermore, in measurement methods that directly output the transition point after a single scan, candidate transition points are typically not verified through neighborhood retesting, and newly added measurement data are not used to refine candidate transition points. When the initial scan resolution is insufficient, the curve fitting results shift, or the candidate position is affected by local noise, the single judgment result may deviate from the actual transition position. Even when multiple microwave response parameters are acquired simultaneously, the change positions and sensitivity of different response parameters may vary. When making independent judgments based on each response parameter, inconsistent candidate results may be obtained, thus affecting the accuracy, repeatability, and automated measurement capabilities of the helium superfluid transition point measurement results.

[0029] To address the aforementioned issues, this application provides a helium superfluid transition point measurement method based on microwave response feature iterative determination. This method acquires microwave response data when the liquid helium under test crosses a predicted superfluid transition range, constructs a microwave characteristic response curve, and determines candidate transition ranges. Within these candidate transition ranges, localized intensified measurements are performed to determine candidate transition points based on high-resolution local microwave response data. Further, neighborhood verification measurements are conducted around the candidate transition points, and the results are used to confirm or update the candidate transition points. Data obtained during the verification process is used to update the local characteristic response curve. This process iteratively executes localized intensified measurements and neighborhood verification measurements until the candidate transition points meet preset determination criteria. Therefore, it combines transition range location over a large area with high-resolution measurements within candidate transition ranges. Neighborhood verification and iterative data updates reduce the impact of measurement noise, link drift, dynamic hysteresis, and local abnormal responses on the transition point determination results, reducing reliance on single scan results and improving the accuracy, repeatability, and robustness of helium superfluid transition point measurement.

[0030] The helium superfluid transition point measurement method based on microwave response feature iterative determination provided in this application can be applied to scenarios such as low-temperature scale reproduction, low-temperature measurement device calibration, liquid helium state identification, superfluid helium condition monitoring, superfluid helium experimental platform debugging, and helium superfluid transition fixed point research.

[0031] The execution subject of the helium superfluid transition point measurement method based on microwave response feature iterative determination provided in this application embodiment can be a helium superfluid transition point measurement device, or an industrial control computer, host computer, cryogenic measurement controller, or a processor integrated into a cryogenic measurement system.

[0032] See Figure 1 The following describes the specific implementation process of the helium superfluid transition point measurement method based on microwave response characteristic iterative determination of the present application. The method may include S101 to S105.

[0033] S101: Adjust the state variables of the liquid helium to be tested so that the measurement state of the liquid helium to be tested crosses the predicted superfluid transition range, and acquire the first microwave response data during the change of state variables.

[0034] The state variable can be an adjustable variable used to control or characterize the state of the liquid helium being measured, such as temperature or pressure. The predicted superfluid transition range can be determined based on the target pressure of the liquid helium, historical measurement results, standard reference data, or pre-conducted calibration tests, and is used to limit the scanning range of the initial measurement.

[0035] To ensure the comparability of subsequent microwave response data, in one feasible implementation, the liquid helium under test can be initially placed in a measurement state close to the estimated superfluid transition range, and the temperature, pressure, and microwave measurement link can be brought to preset stable conditions. Before formally adjusting the state variables, the no-load background data or reference channel data of the microwave measurement link can be recorded to obtain the reference response benchmark required for subsequent response data correction.

[0036] After establishing the initial measurement state, the state variables of the liquid helium to be measured can be adjusted according to the preset scanning direction and initial scanning step size, so that the liquid helium to be measured changes from one side of the estimated superfluid transition range to the other side. The adjustment methods of the state variables can include continuous temperature change, step temperature change, isothermal pressure change, or other adjustment methods that can make the liquid helium to be measured cross the estimated superfluid transition range.

[0037] During the change of state variables, microwave response parameters corresponding to the liquid helium under test can be continuously or intermittently acquired. Microwave response parameters may include at least one of the following: resonant frequency, quality factor, phase, group delay, reflection coefficient, transmission coefficient, and insertion loss. Each set of microwave response data can be associated with the corresponding state variable value and acquisition time to form first microwave response data that characterizes the microwave response change of the liquid helium under test as it crosses the estimated superfluid transition range. Since this stage is mainly used to determine the range in which the superfluid transition may occur, the first microwave response data can also be called coarse scan data.

[0038] S102: Construct a microwave characteristic response curve based on the first microwave response data, and determine the candidate transition interval according to the changing characteristics of the microwave characteristic response curve.

[0039] Specifically, the first microwave response data can be arranged according to the acquisition time or state variable value, and each microwave response parameter can be associated with the corresponding state variable value to obtain the initial response curve of the microwave response parameter changing with the state variable. When the state variable is temperature, a response curve of the microwave response parameter changing with temperature can be constructed; when the state variable is pressure, a response curve of the microwave response parameter changing with pressure can be constructed.

[0040] To reduce the impact of measurement noise and microwave measurement link drift on the curve variation characteristics, in one feasible implementation, the initial response curve can be smoothed, filtered, subjected to baseline subtraction, drift compensation, or differential processing using a reference channel to obtain a corrected microwave characteristic response curve. Baseline subtraction can be used to remove the background trend of slow changes in microwave response parameters with state variables, while differential processing using a reference channel can be used to compensate for frequency drift or environmental fluctuations generated by various channels in the microwave measurement link.

[0041] Furthermore, feature transformations can be performed on the microwave characteristic response curve to obtain the distribution of response characteristics with respect to state variables. The extracted response characteristics can include first-order variation characteristics, second-order variation characteristics, local extrema, inflection points, or peak-valley characteristics. For example, the locations of drastic changes in the microwave response can be determined based on the extremum positions of the first-order variation characteristics, or the inflection point positions of the microwave characteristic response curve can be determined based on the zero-crossing positions of the second-order variation characteristics.

[0042] When multiple microwave response parameters are acquired, the locations of characteristic changes corresponding to different microwave response parameters can be compared, and the range of state variables in which multiple response parameters change significantly at the same time can be identified as candidate transition intervals. Therefore, local areas more likely to undergo superfluid transitions can be selected from larger predicted superfluid transition intervals, providing a range basis for subsequently improving local measurement resolution.

[0043] S103: Locally encrypt and adjust the state variables within the candidate transition interval to obtain the second microwave response data, and determine the candidate transition point based on the second microwave response data.

[0044] Specifically, the local scan step size can be determined based on the width of the candidate transition interval, the acquisition resolution of the first microwave response data, and the degree of change of the microwave characteristic response curve within the candidate transition interval. The local scan step size can be smaller than the initial scan step size used when acquiring the first microwave response data, thereby improving the measurement resolution within the candidate transition interval.

[0045] To reduce the response hysteresis caused by dynamic changes in state variables, a steady-state measurement method can be employed in one feasible implementation. After adjusting the state variable to a sampling position according to the local scan step size, the value of the state variable can be maintained until the liquid helium under test reaches thermodynamic equilibrium or the microwave response parameters reach a stable condition. Then, the microwave response data corresponding to that sampling position is recorded. By traversing the candidate transition intervals in the above manner, second microwave response data can be obtained, which can also be referred to as local high-resolution data.

[0046] After obtaining the second microwave response data, local characteristic response curves corresponding to the candidate transition intervals can be constructed. These local characteristic response curves can then be fitted or subjected to feature analysis to determine the transition characteristic intensity corresponding to different state variable values. The transition characteristic intensity can be used to characterize the degree of microwave response change at the corresponding state variable value.

[0047] In one feasible implementation, the position where the first-order change feature of the local feature response curve reaches an extreme value, the position where the second-order change feature crosses zero, the inflection point of the curve, or the peak-valley position corresponding to the state variable value can be determined as a candidate transition point.

[0048] In another feasible implementation, when the second microwave response data includes response data corresponding to multiple microwave response parameters, the response features of each microwave response parameter can be extracted separately, the extracted response features can be normalized, and then fused according to corresponding weights to obtain joint response features. Subsequently, the state variable values ​​corresponding to the positions where the joint response features reach extreme values ​​can be determined as candidate transition points. By performing joint analysis on multiple microwave response parameters, the candidate position deviation caused by the influence of noise or sensitivity changes on a single microwave response parameter can be reduced.

[0049] S104: Perform neighborhood verification measurements around the candidate transition point to obtain verification response data, and determine the verification result of the candidate transition point based on the verification response data.

[0050] Specifically, with the candidate transition point as the center, verification state variable values ​​can be determined on both sides of the candidate transition point based on the local scan step size, the degree of change in microwave response parameters, or a preset verification range. For example, measurements can be taken at the state variable value corresponding to the candidate transition point, the verification state variable value below the candidate transition point, and the verification state variable value above the candidate transition point.

[0051] The state variables of the liquid helium under test were sequentially adjusted to the candidate transition point and the values ​​of each verification state variable. After the microwave response met the stability condition, the corresponding microwave response data were repeatedly collected to obtain verification response data. The verification response data can be used to characterize the response differences between the candidate transition point and its adjacent state positions.

[0052] Furthermore, the transition characteristic intensity corresponding to each verification state variable value can be compared with that of the candidate transition point, and the direction, magnitude, distribution symmetry, or peak shape consistency of the response changes on both sides of the candidate transition point can be analyzed. When the transition characteristic intensity at the candidate transition point meets the preset extreme value condition, and the response change relationship on both sides of the candidate transition point meets the preset neighborhood verification condition, the candidate transition point can be determined to have passed the verification.

[0053] When the transition feature intensity at a candidate transition point does not meet the preset extreme value condition, or when there is a state variable value with a higher transition feature intensity in the neighborhood, the candidate transition point can be determined to have failed the verification. By performing neighborhood verification on candidate transition points, the possibility of spurious extreme values ​​formed by local noise, random perturbations, or fitting bias being directly determined as helium superfluid transition points can be reduced.

[0054] S105: Based on the verification results, confirm or update the candidate transition points, and iteratively perform local encryption adjustment and neighborhood verification measurement to determine the helium superfluid transition point.

[0055] When a candidate transition point passes verification, it can be confirmed that the candidate transition point meets the preset judgment conditions, and the candidate transition point is identified as a helium superfluid transition point.

[0056] When a candidate transition point fails verification, the obtained verification response data can be incorporated into the second microwave response data to update the local characteristic response curve corresponding to the candidate transition interval. Based on the updated local characteristic response curve, the extreme value position of the transition feature intensity can be re-determined, and the candidate transition point and its corresponding candidate transition interval can be updated according to the feature deviation between the original candidate transition point and the updated extreme value position.

[0057] After updating the candidate transition points, local encryption adjustments can be performed again within the updated candidate transition interval, and neighborhood verification measurements can be performed again around the updated candidate transition points. This process is repeated, with the new data obtained from each neighborhood verification being used to update the local feature response curve and candidate transition points, until the candidate transition point passes neighborhood verification, or the difference between two adjacent candidate transition points is no greater than a preset convergence threshold.

[0058] The candidate transition points can be updated using Newton's iteration, linear extrapolation, bisection approximation, secant iteration, adaptive step-size iteration, or a cost function-based search method. The preset convergence threshold can be determined based on the stability of the state variables, local scan resolution, and measurement uncertainty.

[0059] The helium superfluid transition point measurement method provided in this application, based on iterative determination of microwave response characteristics, acquires the first microwave response data when the liquid helium under test crosses the estimated superfluid transition interval, constructs a microwave characteristic response curve, and determines candidate transition intervals. This method can first locate the local range where the microwave response characteristic changes occur within a large measurement range. Then, it performs local densification adjustment within the candidate transition interval and determines the candidate transition point based on the high-resolution second microwave response data. This improves the measurement resolution near the transition point while avoiding high-density scanning of the entire measurement range. Furthermore, it performs neighborhood verification measurement around the candidate transition point, confirms or updates the candidate transition point based on the verification results, and uses the data obtained during the verification process for subsequent iterative updates of candidate transition points. This forms a closed-loop determination process between local densification measurement, neighborhood verification, and candidate transition point updates, reducing the impact of single-scan noise, microwave measurement link drift, dynamic response hysteresis, and local fitting deviation on the transition point determination results. It also reduces the possibility of misjudging accidental extreme values ​​or pseudo-feature positions as helium superfluid transition points, thereby improving the accuracy, repeatability, robustness, and automation of helium superfluid transition point measurement.

[0060] The following describes the specific process of constructing microwave characteristic response curves and determining candidate transition intervals based on the first microwave response data. (See reference...) Figure 2 It may include S201 to S204.

[0061] S201: Associate the first microwave response data with the corresponding state variable values ​​to obtain the initial response curve of the microwave response parameters as the state variables change.

[0062] When adjusting the state variables of the liquid helium under test and acquiring the first microwave response data, the state variable values ​​and acquisition times corresponding to each set of microwave response data can be recorded simultaneously. After obtaining the first microwave response data, the microwave response data can be correlated with the state variable data according to the acquisition time, and the correlated data can be arranged according to the state variable values.

[0063] When the first microwave response data includes response data corresponding to resonant frequency, quality factor, phase, and group delay, initial response curves for each microwave response parameter as a function of the state variable can be constructed separately. Taking temperature or pressure as an example, the initial response curve for temperature can be expressed as follows: (1); The initial pressure response curve can be represented as: (2); Where T represents temperature and P represents pressure. Indicates the resonant frequency. Indicates the quality factor. Indicates phase, Indicates group delay. The initial response curve representing temperature. The initial response curve represents the pressure.

[0064] S202: Correct the initial response curve to obtain the corrected response curve.

[0065] Microwave measurement links may suffer from frequency drift, environmental background fluctuations, and random measurement noise. The initial response curve may also contain slow changing trends that do not reflect the liquid helium state transition. To reduce the impact of these factors on the candidate transition interval identification results, the initial response curve can be smoothed, filtered, have its baseline subtracted, drift compensated, or differentially processed using a reference channel.

[0066] Taking the resonant frequency as an example, when a reference channel frequency is pre-acquired, the differential frequency can be obtained based on the difference between the frequency of the channel to be measured and the reference channel frequency: (3); in, This indicates the resonant frequency corresponding to the liquid helium being tested. Indicates the reference channel frequency. This indicates the frequency change after differential processing through the reference channel.

[0067] When the background trend term is obtained by fitting the initial response curve, the resonant frequency can also be normalized and corrected. (4); in, This represents the background trend term obtained by fitting the initial response curve. This represents the change in frequency after background subtraction and normalization.

[0068] For quality factor, phase, group delay, or other microwave response parameters, corresponding differential or normalization methods can also be used. Different correction methods can be used individually or in combination according to the noise and drift characteristics of the microwave measurement link.

[0069] S203: Perform a characteristic transformation on the corrected response curve to obtain the distribution of response characteristics as a function of state variables.

[0070] Specifically, first-order variation analysis, second-order variation analysis, local extremum analysis, inflection point analysis, or peak-valley analysis can be performed on the correction response curve to amplify the local changes in microwave response parameters when liquid helium crosses the superfluid transition region.

[0071] Taking the resonant frequency after differential processing via the reference channel as an example, its first-order derivative characteristics and second-order derivative characteristics can be expressed as follows: (5); (6); in, It represents the first derivative, used to characterize the rate of frequency change at different temperature locations; It represents the second derivative, used to characterize the rate of change of frequency.

[0072] To reduce the noise amplification caused by directly calculating the derivative of discrete sampled data, the correction response curve can be fitted with a local polynomial, spline, or peak-valley model first, and then the corresponding derivative characteristics can be calculated based on the continuous curve obtained from the fitting.

[0073] S204: Determine the candidate transition interval based on the range of state variables that meet the preset transition criteria according to the response characteristics.

[0074] Specifically, the extreme values ​​of the first derivative features, the zero-crossing positions of the second derivative features, the local peak and valley positions, or the inflection points of the curves can be searched within the scanning range of the state variables, and the candidate transition intervals can be determined based on the distribution range of the corresponding feature positions.

[0075] For example, when a local extreme value appears near a certain temperature location, or when the temperature crosses zero near that location and the sign changes before and after the zero crossing, the continuous temperature range near that temperature location can be identified as a candidate transition interval.

[0076] When the first microwave response data includes multiple microwave response parameters, the characteristic change locations of each microwave response parameter can be determined separately. If multiple parameters, such as resonant frequency, quality factor, phase, or group delay, show significant changes within the same or adjacent ranges of state variables, candidate transition intervals can be determined based on the overlapping or proximity of the multiple characteristic change locations. This reduces the impact of random fluctuations in a single microwave response parameter on the candidate transition interval identification results.

[0077] In some embodiments, when performing local encryption adjustment on the state variable within the candidate transition interval, the local scanning step size can be determined first based on the interval width of the candidate transition interval and the acquisition resolution of the first microwave response data. The scanning step size used when acquiring the first microwave response data can be referred to as the first scanning step size, and the scanning step size used for local encryption adjustment can be referred to as the second scanning step size, wherein the second scanning step size is smaller than the first scanning step size.

[0078] For example, the second scan step size can be determined based on the number of sampling points required within the candidate transition interval, or it can be adaptively determined based on the degree of change of the microwave characteristic response curve within the candidate transition interval. When the microwave response changes relatively smoothly, a relatively large second scan step size can be used; when the microwave response changes more drastically, the second scan step size can be reduced, thereby obtaining denser measurement data in the local area where the transition characteristics are more obvious.

[0079] After adjusting the state variable to the corresponding sampling position according to the second scan step size, the current state variable value can be maintained, and it can be determined whether the liquid helium under test has reached thermodynamic equilibrium or whether the microwave response has reached a stable condition. The microwave response stability condition can be determined based on the change in microwave response parameters within a preset time range. When the change in microwave response parameters is not greater than the preset stability threshold, the microwave response data corresponding to the current sampling position is recorded. By traversing the candidate transition intervals in the above manner, the second microwave response data can be obtained.

[0080] In some embodiments, local characteristic response curves corresponding to candidate transition intervals can be constructed based on the second microwave response data, and local response functions can be obtained through local polynomial fitting, spline fitting, or peak-valley fitting.

[0081] When using the first derivative extremum criterion, the location where the first derivative of the local response function reaches its maximum or minimum value can be identified as a candidate transition point: (7); in, This indicates the initially identified candidate turning point. This is a local response function.

[0082] When using the zero-crossing criterion of the second derivative, the temperature that satisfies the following equation and whose second derivative changes sign on both sides of the position can be identified as a candidate transition point: (8); When using multi-parameter joint determination, a joint feature function can be constructed as follows: (9); in, For joint characteristic functions, , , These are the normalized derivatives of frequency, quality factor, and phase characteristic, respectively. These are the weighting coefficients. Take... The extreme points are used as candidate transition points initially determined. .

[0083] In other embodiments, candidate transition points can be determined based on the intersection of peak values, valley values, or preset thresholds of local characteristic response curves. The method for determining candidate transition points can be selected based on the microwave response parameters used and their variation within the superfluid transition range.

[0084] The following explains the specific process of neighborhood verification and iterative update of candidate transition points. (See also...) Figure 3 It may include S301 to S305.

[0085] S301: Determine the neighborhood verification range based on the candidate transition points, and determine multiple verification state variable values ​​within the neighborhood verification range.

[0086] Specifically, the verification interval can be determined based on the candidate transition point as the center, the local scanning step size, the candidate transition interval width, and the degree of change of microwave response parameters, and , and are determined as the state variable values ​​used for neighborhood verification measurement.

[0087] The validation interval can be the same as the local scan step size, or it can be adjusted according to the degree of response change near the candidate transition point. When the response change near the candidate transition point is more drastic, the validation interval can be reduced; when the response change is relatively gentle, the validation interval can be appropriately increased.

[0088] S302: Adjust the state variables of the liquid helium to be tested to the candidate transition point and the values ​​of each verification state variable to obtain the corresponding verification response data.

[0089] Specifically, the state variables can be sequentially adjusted to the candidate transition point and the verification state variable values ​​on both sides according to a preset adjustment sequence. The measurement state of the liquid helium to be tested is maintained at each verification state variable value, and verification response data is collected after the microwave response meets the stability condition.

[0090] To reduce the lag effect caused by the order of state variable adjustment, measurements can be performed in a sequence from low to high, from high to low, or alternating between candidate transition points and verification points on both sides. One or more sets of verification response data can be collected at each verification state variable value, and random measurement noise can be reduced by averaging.

[0091] S303: Determine the verification result of the candidate transition point based on the verification response data corresponding to the candidate transition point and the values ​​of each verification state variable.

[0092] Specifically, the transition feature strengths corresponding to candidate transition points and each verification state variable value can be calculated based on the verification response data, and the feature strength relationship between the candidate transition points and the verification state variable values ​​on both sides can be compared.

[0093] When the joint response characteristics at the candidate transition point achieve the strongest local response, the absolute value of the first derivative at the candidate transition point reaches a local maximum, the response changes on both sides of the candidate transition point are opposite and satisfy the preset symmetry condition, or the deviation of the candidate transition point obtained from multiple verifications is within the preset measurement uncertainty range, the candidate transition point can be determined to have passed the verification.

[0094] When the transition feature strength at a candidate transition point is lower than the transition feature strength corresponding to at least one verification state variable value, or when the response change relationship on both sides of the candidate transition point does not meet the preset verification conditions, it can be determined that the candidate transition point has failed verification.

[0095] S304: If a candidate transition point fails verification, the verification response data is incorporated into the second microwave response data, and the candidate transition point and candidate transition range are updated.

[0096] Specifically, the verification response data corresponding to the candidate transition point and the verification state variable values ​​on both sides can be added to the dataset of the candidate transition interval, and the curve fitting and feature calculation can be performed again to obtain the updated local feature response curve.

[0097] The feature deviation of candidate transition points can be determined based on the updated local feature response curves, and the candidate transition points can be updated according to this feature deviation. In one feasible implementation, Newton's iteration method can be used to update candidate transition points: (10); in, This represents the candidate transition point determined in the nth iteration. Indicates the updated candidate transition point. This represents the objective function used to characterize the degree of deviation of the transformation features. This represents the iteration step size factor.

[0098] In another feasible implementation, linear extrapolation can be performed based on the values ​​of two adjacent state variables and their corresponding characteristic deviations: (11); in, and This indicates the temperature state variable values ​​used in two consecutive verifications. and This indicates the corresponding characteristic deviation, such as the difference between the left and right slopes, the derivative deviation, or the joint deviation of multiple parameters.

[0099] In addition to the methods mentioned above, candidate transition points can also be updated using binary approximation, secant iteration, adaptive step-size iteration, or a search method based on minimizing the cost function. After updating the candidate transition points, the candidate transition interval can be redefined with the updated candidate transition points as the center.

[0100] S305: Re-perform local encryption measurement and neighborhood verification measurement based on the updated candidate transition interval until the candidate transition point meets the convergence condition.

[0101] Specifically, the second microwave response data can be reacquired within the updated candidate transition interval to determine new candidate transition points, and neighborhood verification can be performed around these new candidate transition points. If the new candidate transition points still fail verification, the newly added verification response data is incorporated into the existing dataset to update the local feature response curves and candidate transition points.

[0102] Two adjacent candidate transition points can satisfy the following convergence condition: (12); in, This represents the convergence threshold. The convergence threshold can be determined based on temperature control stability, sampling resolution, or measurement uncertainty.

[0103] When a candidate transition point passes neighborhood verification and meets the convergence condition, the iteration can be stopped, and the converged candidate transition point is determined as the helium superfluid transition point. If the candidate transition point does not yet meet the convergence condition, the process returns to the local encryption measurement step to continue updating the candidate transition point.

[0104] In some embodiments, after a candidate transition point meets a preset judgment condition, multiple independent repeated measurements can be performed around the converged candidate transition point. Each independent repeated measurement can re-execute local encryption adjustment, candidate transition point calculation, and neighborhood verification to obtain the corresponding transition point measurement result.

[0105] The arithmetic mean of multiple transition point measurements can be used as the final helium superfluid transition point: (13); in, Indicates the number of independent repeated measurements. This indicates the finally determined helium superfluid transition point. Indicates the first The helium superfluid transition point obtained from multiple independent repeated measurements.

[0106] Measurement repeatability can also be determined based on the dispersion between measurements at multiple transition points. For example, the standard deviation of repeatability can be expressed as: (14); in, This represents the repeatability standard deviation. The smaller the repeatability standard deviation, the more concentrated the change point measurement results obtained from multiple independent measurements are, and the higher the measurement repeatability.

[0107] In some embodiments, the second microwave response data may include response data corresponding to multiple microwave response parameters. Response features can be extracted from the local response curves corresponding to each microwave response parameter, and each response feature can be normalized to reduce the differences in dimensions and numerical ranges between different microwave response parameters.

[0108] Subsequently, the normalized response features can be weighted and fused according to preset weights to obtain joint response features.

[0109] Each weighting coefficient can be predetermined based on the system characteristics of the microwave measurement link or the response of each microwave response parameter within the superfluid transition range. Normalized response characteristics corresponding to group delay, reflection coefficient, transmission coefficient, or insertion loss can also be added to the joint response characteristics. The location where an extreme value is obtained can be determined as a candidate transition point, or the values ​​at different state variable values ​​can be used as the corresponding transition characteristic intensities.

[0110] In some embodiments, the state variable may include temperature or pressure. When the state variable is temperature, the liquid helium to be tested can be made to cross the estimated superfluid transition range by means of continuous heating, continuous cooling, step heating, step cooling, or alternating heating and cooling. When the state variable is pressure, the pressure can be adjusted while keeping the temperature relatively stable, or the liquid helium to be tested can be made to cross the estimated superfluid transition range by means of increasing pressure, decreasing pressure, or alternating heating and cooling.

[0111] When using a reciprocating adjustment method, the candidate transition interval can be crossed first along the first adjustment direction, and the measurement result of the first transition point can be determined based on the microwave response data corresponding to the first adjustment direction. Then, the candidate transition interval can be crossed again along the opposite second adjustment direction, and the measurement result of the second transition point can be determined based on the microwave response data corresponding to the second adjustment direction. The arithmetic mean of the two transition point measurement results or the joint fitting of the response data corresponding to the two adjustment directions can be performed to obtain a hysteresis-compensated candidate transition point, which is then used as the initial position for neighborhood verification and iterative updates. This reduces the impact of dynamic response hysteresis caused by a single adjustment direction on the transition point measurement results.

[0112] In some embodiments, microwave response parameters may include at least one of resonant frequency, quality factor, phase, group delay, reflection coefficient, transmission coefficient, and insertion loss. The resonant frequency can reflect changes in the resonant position caused by variations in the dielectric properties of liquid helium; the quality factor can reflect changes in microwave energy loss characteristics; the phase and group delay can reflect changes in microwave signal transmission characteristics; and the reflection coefficient, transmission coefficient, and insertion loss can reflect the reflection, transmission, and attenuation of the microwave signal in the measurement link.

[0113] When correcting the initial response curve, one or more of the following methods can be selected based on the data characteristics: smoothing, filtering, baseline subtraction, drift compensation, and reference channel differential processing. Smoothing and filtering can be used to reduce random noise; baseline subtraction can be used to remove background trends that change slowly with the state variable; drift compensation can be used to reduce parameter drift caused by the microwave measurement link over time; and reference channel differential processing can be used to cancel environmental disturbances experienced by both the measured channel and the reference channel. These correction methods can be combined in different orders to obtain a microwave characteristic response curve that accurately characterizes the state changes of the liquid helium under test.

[0114] Figure 4 This is a block diagram of a helium superfluid transition point measurement device based on iterative determination of microwave response characteristics, provided as an embodiment of this application. Figure 4 As shown, the helium superfluid transition point measurement device based on microwave response characteristic iterative determination includes: The data acquisition module 401 is used to adjust the state variable of the liquid helium to be tested so that the measurement state of the liquid helium to be tested crosses the estimated superfluid transition range, and to acquire the first microwave response data during the change of the state variable. The interval identification module 402 is used to construct a microwave characteristic response curve based on the first microwave response data, and determine candidate transition intervals according to the changing characteristics of the microwave characteristic response curve. The local measurement module 403 is used to perform local encryption adjustment on the state variable within the candidate transition interval, obtain second microwave response data, and determine the candidate transition point based on the second microwave response data. The verification module 404 is used to perform neighborhood verification measurement around the candidate transition point, obtain verification response data, and determine the verification result of the candidate transition point based on the verification response data. The iterative determination module 405 is used to confirm or update the candidate transition point based on the verification result, and iteratively perform local encryption adjustment and neighborhood verification measurement to determine the helium superfluid transition point.

[0115] The helium superfluid transition point measuring device based on microwave response characteristic iterative determination provided in this application embodiment can execute the method shown in the above method embodiment. Its implementation principle and beneficial effects can be found in the relevant descriptions in the method embodiment, and will not be repeated here. Furthermore, each module in the above-mentioned helium superfluid transition point measuring device based on microwave response characteristic iterative determination can be implemented entirely or partially through software, hardware, or a combination thereof. Each of the above modules can be embedded in or independent of the processor in a computer device in hardware form, or stored in the memory of a computer device in software form, so that the processor can call and execute the operations corresponding to each of the above modules.

[0116] In other embodiments, an electronic device is provided, which may be the helium superfluid transition point measurement device based on microwave response characteristic iterative determination in the above method embodiments, for executing the method steps executed by the terminal in the above method flow.

[0117] This application also provides a computer-readable storage medium storing computer instructions. When these computer instructions are executed by a processor, they are used to implement the technical solution of the helium superfluid transition point measurement method based on microwave response characteristics iterative determination in the above embodiments. Specifically, when the computer instructions are executed by a processor, the computer device can execute the technical solution of the helium superfluid transition point measurement method based on microwave response characteristics iterative determination provided in the above embodiments.

[0118] This application also provides a computer program product, which includes a computer program stored in a computer-readable storage medium. At least one processor can read the computer program from the computer-readable storage medium. When the at least one processor executes the computer program, it can implement the technical solution of the helium superfluid transition point measurement method based on microwave response characteristic iterative determination provided in the above embodiments.

[0119] The technical parameters in the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical parameters in the above embodiments are described. However, as long as these combinations of technical parameters do not contradict each other, they should be considered within the scope of this specification. The above embodiments only illustrate several implementation methods of this application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of this application's patent. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

[0120] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical parameters. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A method for measuring the helium superfluid transition point based on iterative determination of microwave response characteristics, characterized in that, include: The state variables of the liquid helium to be tested are adjusted so that the measurement state of the liquid helium to be tested crosses the predicted superfluid transition range, and the first microwave response data during the change of the state variables are obtained. A microwave characteristic response curve is constructed based on the first microwave response data, and candidate transition intervals are determined according to the changing characteristics of the microwave characteristic response curve. Within the candidate transition interval, the state variable is locally encrypted and adjusted to obtain second microwave response data, and candidate transition points are determined based on the second microwave response data; Neighborhood verification measurements are performed around the candidate transition point to obtain verification response data, and the verification result of the candidate transition point is determined based on the verification response data. Based on the verification results, the candidate transition points are confirmed or updated, and local encryption adjustment and neighborhood verification measurements are iteratively performed to determine the helium superfluid transition point.

2. The method according to claim 1, characterized in that, The step of constructing a microwave characteristic response curve based on the first microwave response data and determining candidate transition intervals based on the changing characteristics of the microwave characteristic response curve includes: The first microwave response data is correlated with the corresponding state variable value to obtain the initial response curve of the microwave response parameters as the state variable changes. The initial response curve is corrected and its characteristics are transformed to obtain the distribution of response characteristics as a function of the state variables; The candidate transition interval is determined based on the range of state variables that satisfy the preset transition criteria according to the response characteristics.

3. The method according to claim 1, characterized in that, The step of locally encrypting and adjusting the state variable within the candidate transition interval to obtain the second microwave response data includes: The local scan step size is determined based on the width of the candidate transition interval and the acquisition resolution of the first microwave response data; The state variables are adjusted within the candidate transition interval according to the local scanning step size, and microwave response data is collected after the microwave response corresponding to each state variable value meets the stability condition to obtain the second microwave response data.

4. The method according to claim 1, characterized in that, The step of determining candidate transition points based on the second microwave response data includes: Construct local characteristic response curves corresponding to the candidate transition intervals based on the second microwave response data; Based on the local change characteristics of the local feature response curve at different state variable values, determine the intensity of the transition characteristics corresponding to each state variable value; The state variable values ​​whose transformation feature strength meets the preset extreme value condition are determined as the candidate transformation points.

5. The method according to claim 1, characterized in that, The neighbor-to-neighborhood verification measurement around the candidate transition point to obtain verification response data includes: The neighborhood verification range is determined based on the candidate transition points, and multiple verification state variable values ​​are determined within the neighborhood verification range; The state variables of the liquid helium to be tested are adjusted to the candidate transition points and the values ​​of each of the verification state variables, respectively, to obtain the corresponding verification response data; The verification result is determined based on the difference in transition characteristic intensity between the candidate transition point and each of the verification state variable values, as well as the response change relationship on both sides of the candidate transition point.

6. The method according to claim 1, characterized in that, Updating the candidate transition point based on the verification result includes: When the candidate transition point fails verification, the verification response data is incorporated into the second microwave response data to update the local feature response curve; The feature deviation of the candidate transition point is determined based on the updated local feature response curve, and the candidate transition point and the candidate transition interval are updated based on the feature deviation. Based on the updated candidate transition interval, local encryption adjustment and neighborhood verification measurement are performed again until the difference between two adjacent candidate transition points satisfies the convergence condition.

7. The method according to claim 1, characterized in that, The method further includes: Local encryption adjustment and neighborhood verification measurement are repeatedly performed around candidate transition points that meet the preset judgment conditions to obtain multiple transition point measurement results; The helium superfluid transition point is determined based on multiple transition point measurements, and measurement repeatability is determined based on the degree of dispersion among the multiple transition point measurements.

8. The method according to claim 4, characterized in that, The second microwave response data includes response data corresponding to multiple microwave response parameters; Determining the transition characteristic intensity corresponding to each state variable value includes: Response features are extracted from the response data corresponding to each microwave response parameter, and the extracted response features are normalized. The normalized response features are weighted and fused to obtain joint response features; The intensity of the transition features corresponding to the values ​​of each state variable is determined based on the changes in the joint response features with the state variables.

9. The method according to claim 1, characterized in that, The state variables include temperature or pressure, and the adjustment methods for the state variables include continuous adjustment, step adjustment, or reciprocating adjustment. When using the reciprocating adjustment, the transition point measurement results are determined based on the microwave response data corresponding to the two opposite adjustment directions, and the transition point measurement results corresponding to the two adjustment directions are fused to obtain candidate transition points after hysteresis compensation.

10. The method according to claim 2, characterized in that, The microwave response parameters include at least one of the following: resonant frequency, quality factor, phase, group delay, reflection coefficient, transmission coefficient, and insertion loss. The correction process includes at least one of smoothing, filtering, baseline subtraction, drift compensation, and reference channel differential processing.

11. A helium superfluid transition point measurement device based on microwave response characteristic iterative determination, characterized in that, include: The data acquisition module is used to adjust the state variables of the liquid helium to be tested so that the measurement state of the liquid helium to be tested crosses the predicted superfluid transition range, and to acquire the first microwave response data during the change of the state variables. The interval identification module is used to construct a microwave characteristic response curve based on the first microwave response data, and determine candidate transition intervals according to the changing characteristics of the microwave characteristic response curve. A local measurement module is used to perform local encryption adjustment on the state variable within the candidate transition interval, obtain second microwave response data, and determine the candidate transition point based on the second microwave response data. The verification module is used to perform neighborhood verification measurements around the candidate transition point, obtain verification response data, and determine the verification result of the candidate transition point based on the verification response data. The iterative determination module is used to confirm or update the candidate transition point based on the verification result, and iteratively perform local encryption adjustment and neighborhood verification measurement to determine the helium superfluid transition point.

12. An electronic device, characterized in that, include: The electronic device comprises a memory, a communication interface, and at least one processor; the memory is communicatively connected to the processor; the memory is used to store computer program code, the computer program code including computer instructions; when the processor executes the computer instructions, the electronic device performs the method as described in any one of claims 1-10.

13. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions that, when executed by a processor, are used to implement the method as described in any one of claims 1-10.

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