A method for measuring the resistance of MgB2 superconducting wire-based superconductivity ratio

Abstract

The application belongs to the technical field of superconducting wire base-super ratio measurement, and discloses a resistance measurement method of MgB2 superconducting wire base-super ratio. The MgB2 superconducting wire belongs to a new type of superconducting wire combining external stability and dispersion stability. According to the parallel principle, the volume ratio β2 of the external stability body Monel of the MgB2 superconducting wire sample and all components (Cu+Nb+MgB2) in the internal part of the MgB2 superconducting wire sample is calculated first; then the volume ratio β1 of the dispersion stability body oxygen-free copper of the MgB2 superconducting wire sample and (Nb+MgB2) is calculated; and β3 is the volume ratio of the Nb tube of the MgB2 superconducting wire sample and MgB2. The base-super ratio β of the MgB2 superconducting wire is calculated in combination with the above volume ratio and the sample cross-sectional area relationship. A large number of test comparison experiments show that the test comparison error of the method of the application and the paper weighing method is within 4%, and the use demand is met. Compared with the paper weighing method, the efficiency of the method of the application is improved by more than 90%.

Description

Technical Field

[0001] This invention relates to the field of superconducting wire-superconducting ratio measurement technology, specifically to a method for measuring the resistance of MgB2 superconducting wire-superconducting ratio. Background Technology

[0002] MgB2 is an important research hotspot in the modern field of superconductivity. It is a new type of high-temperature superconducting wire that can be used in products such as superconducting cables, superconducting current limiters, and superconducting transformers.

[0003] The basis-to-superconductor ratio (BTR) is a crucial performance indicator for MgB2 superconducting wires, significantly impacting the calculation of their critical current density. Currently, the BTR is mostly measured using a paper weighing method. However, this traditional method involves vertically embedding the sample in resin for polishing. Sample polishing relies on sophisticated techniques, and the entire process—from polishing, photographing, copying, cutting, weighing, to the final BTR calculation—takes approximately 2 hours. Therefore, the paper weighing method not only depends on skilled sample polishers but also suffers from a time constraints that cannot meet production demands, resulting in a long overall testing cycle and low efficiency. Summary of the Invention

[0004] The purpose of this invention is to provide a method for measuring the resistance of MgB2 superconducting wire with a superconducting ratio, so as to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A method for measuring the resistance of MgB2 superconducting wire-based superconductivity includes the following steps:

[0007] A mathematical model was established for the ratio of the base material to the superconductivity, and the ratio of the cross-sectional area to the volume of the MgB2 superconducting wire.

[0008] Obtain MgB2 superconducting wire samples;

[0009] Obtain the volume ratio of the outer stabilizer Monel of the MgB2 superconducting wire sample to all its internal components (Cu+Nb+MgB2);

[0010] Obtain the volume ratio of oxygen-free copper to (Nb+MgB2) in the dispersion stabilizer of the MgB2 superconducting wire sample.

[0011] Obtain the volume ratio of Nb tube to MgB2 in the MgB2 superconducting wire sample;

[0012] Obtain the cross-sectional area of ​​the MgB2 superconducting wire sample;

[0013] The MgB2 superconducting wire base-superconductor ratio is determined based on the mathematical model, cross-sectional area, volume ratio of the external stabilizer Monel to all its internal components (Cu+Nb+MgB2), volume ratio of the dispersed stabilizer oxygen-free copper to (Nb+MgB2), and volume ratio of Nb tube to MgB2.

[0014] More preferably, the mathematical model is:

[0015]

[0016] In the formula, β is the basis-to-superconductor ratio of the MgB2 superconducting wire; S is the cross-sectional area of ​​the MgB2 superconducting wire sample; β2 is the volume ratio of the external stabilizer Monel to all its internal components (Cu+Nb+MgB2); β1 is the volume ratio of the dispersed stabilizer oxygen-free copper to (Nb+MgB2) in the MgB2 superconducting wire sample; and β3 is the volume ratio of the Nb tube to MgB2 in the MgB2 superconducting wire sample. The MgB2 superconducting wire is a novel type of superconducting wire combining external stabilization and dispersed stabilization. Based on the parallel principle, the volume ratio β2 of the external stabilizer Monel to all its internal components (Cu+Nb+MgB2) of the MgB2 superconducting wire sample is first calculated; then the volume ratio β1 of the dispersed stabilizer oxygen-free copper to (Nb+MgB2) in the MgB2 superconducting wire sample is calculated; and β3 is the volume ratio of the Nb tube to MgB2 in the MgB2 superconducting wire sample. The basis-to-superconductor ratio β of the MgB2 superconducting wire is then calculated by combining the above volume ratios with the sample cross-sectional area.

[0017] More preferably, the volume ratio of the outer stabilizer Monel of the MgB2 superconducting wire to all its internal components (Cu+Nb+MgB2) is calculated as follows:

[0018]

[0019] In the formula, ρ M ρ is the resistivity of the Monel alloy in the MgB2 superconducting wire sample; L is the length of the voltage gap in the MgB2 superconducting wire sample; X R represents the overall resistivity of the Monel body, the external stabilizer of the MgB2 superconducting wire, and all its internal components (Cu+Nb+MgB2). m S represents the total resistance of the wire; S is the cross-sectional area of ​​the MgB2 superconducting wire sample. A mathematical model is established for the volume ratio β2 of the external stabilizer Monel and all its internal components (Cu+Nb+MgB2) of the MgB2 superconducting wire: The MgB2 superconducting wire is considered as two parts, one being Monel and the other being all its internal components (Cu+Nb+MgB2), treated as a whole, and β2 is calculated based on the parallel principle.

[0020] More preferably, the volume ratio of the oxygen-free copper to (Nb+MgB2) in the dispersion stabilizer of the MgB2 superconducting wire sample is calculated as follows:

[0021]

[0022] In the formula, ρ Cu ρ is the resistivity of oxygen-free copper in the MgB2 superconducting wire sample; L is the length of the voltage gap in the MgB2 superconducting wire sample; Y The overall resistivity of oxygen-free copper and (Nb+MgB2) in the dispersion stabilizer of the MgB2 superconducting wire sample; ρ X Monel, the external stabilizer of MgB2 superconducting wire, and all its internal components

[0023] The overall resistivity of (Cu+Nb+MgB2). The calculation of the volume ratio β1 of the oxygen-free copper dispersion stabilizer to (Nb+MgB2) in the MgB2 superconducting wire sample: considering all components inside the Monel of MgB2 as a dispersed and stable superconductor, the volume ratio β1 of the dispersed and stable oxygen-free copper to the superconducting region is derived based on the parallel principle.

[0024] More preferably, β3 is the volume ratio of Nb tubes to MgB2 in the MgB2 superconducting wire sample, and since all Nb tubes are identical, β3 is a constant value.

[0025] More preferably, in formulas (2) and (3), ρ Cu ρ Y ρ M and ρ X The specific method of obtaining it includes the following steps:

[0026] Step 1: Measure the resistance of oxygen-free copper in the MgB2 superconducting wire sample as a function of temperature, and calculate the fitted value ρ. Cu The relationship between temperature and temperature is calculated using the following formula:

[0027] ρ Cu =ρ Cu_293K ×(1+A1×(T-293)) (4),

[0028] In the formula, ρ Cu The resistivity (mΩ*mm) of oxygen-free copper in the MgB2 superconducting wire sample; ρ Cu_293K A1 is the resistivity (mΩ*mm) of oxygen-free copper in the MgB2 superconducting wire sample at 293K; A1 is the temperature coefficient of resistivity of oxygen-free copper in the MgB2 superconducting wire sample; T is the temperature (273K~315K).

[0029] Step 2: Measure the overall resistivity of the oxygen-free copper and (Nb+MgB2) dispersion stabilizer in the MgB2 superconducting wire sample as a function of temperature, and calculate the fitted value ρ. YThe relationship between temperature and temperature is calculated using the following formula:

[0030] ρ Y =ρ Y_293K ×(1+A2×(T-293)) (5),

[0031] In the formula, ρ Y The overall resistivity (mΩ*mm) of oxygen-free copper and (Nb+MgB2) in the dispersion stabilizer of the MgB2 superconducting wire sample; ρ Y_293K A1 represents the resistivity (mΩ*mm) of the oxygen-free copper dispersion stabilizer and (Nb+MgB2) as a whole in the MgB2 superconducting wire sample at 293 K; A2 represents the temperature coefficient of resistivity of the oxygen-free copper dispersion stabilizer and (Nb+MgB2) as a whole in the MgB2 superconducting wire sample; T represents the temperature (273 K~315 K).

[0032] Step 3: The resistivity of the Monel alloy sample of the MgB2 superconducting wire is calculated using the following formula:

[0033] ρ M =0.482mΩ*mm (6);

[0034] Step 4: Take a MgB2 superconducting wire sample with a known β2 as a standard sample, measure the specifications of the standard MgB2 superconducting wire sample, measure the change in resistance of the standard MgB2 superconducting wire sample with temperature, and calculate and fit the overall resistivity ρ of all components inside the Monel alloy to obtain the overall resistivity ρ. X The relationship between temperature and temperature is calculated using the following formula:

[0035] ρ X =ρ X_293K ×(1+A3×(T-293)) (7),

[0036] In the formula, ρ X The resistivity (mΩ*mm) of the Monel body, the external stabilizer of the MgB2 superconducting wire, and all its internal components (Cu+Nb+MgB2); ρ X_293K A1 is the resistivity (mΩ*mm) of the Monel body, the external stabilizer of the MgB2 superconducting wire, and all its internal components (Cu+Nb+MgB2) at 293 K; A2 is the temperature coefficient of resistivity of the Monel body, the external stabilizer of the MgB2 superconducting wire, and all its internal components (Cu+Nb+MgB2); T is the temperature (273 K~315 K).

[0037] Compared with the prior art, the beneficial effects of the present invention are:

[0038] This invention provides a method for measuring the base-to-superconductor ratio resistance of MgB2 superconducting wire. In the measurement process, it replaces the traditional paper weighing method for testing the base-to-superconductor ratio of MgB2 superconducting wire, eliminating the reliance on personnel polishing the samples that was necessary for the traditional method. Furthermore, the testing time for a single sample is reduced from 120 minutes to 3 minutes, significantly improving testing efficiency. Attached Figure Description

[0039] Figure 1 The resistivity ρ of oxygen-free copper Cu Changes with temperature;

[0040] Figure 2 The resistivity ρ of (Nb+MgB2) Y Changes with temperature;

[0041] Figure 3 The overall resistivity ρ of (Cu+Nb+MgB2) X Changes with temperature;

[0042] Figure 4 It is based on the principle of the four-wire method for measuring resistance;

[0043] Figure 5 This is a comparison of the method of the present invention with the matrix-to-ultra ratio test of MgB2 samples using the paper weighing method;

[0044] Figure 6 This is a cross-sectional view of the MgB2 superconducting wire of the present invention. Detailed Implementation

[0045] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0046] Please see Figure 1-6 The present invention provides a technical solution:

[0047] A method for measuring the resistance of MgB2 superconducting wire-based superconductivity includes the following steps:

[0048] A mathematical model for the ratio of MgB2 superconducting wire to superconducting wire, as well as the ratio of cross-sectional area to volume, is established in this invention. The mathematical model is as follows:

[0049]

[0050] In the formula, β is the basis-to-superconductor ratio of the MgB2 superconducting wire; S is the cross-sectional area of ​​the MgB2 superconducting wire sample; β2 is the volume ratio of the external stabilizer Monel to all its internal components (Cu+Nb+MgB2); β1 is the volume ratio of the dispersed stabilizer oxygen-free copper to (Nb+MgB2) in the MgB2 superconducting wire sample; and β3 is the volume ratio of the Nb tube to MgB2 in the MgB2 superconducting wire sample. The MgB2 superconducting wire is a novel type of superconducting wire combining external stabilization and dispersed stabilization. Based on the parallel principle, the volume ratio β2 of the external stabilizer Monel to all its internal components (Cu+Nb+MgB2) of the MgB2 superconducting wire sample is first calculated; then the volume ratio β1 of the dispersed stabilizer oxygen-free copper to (Nb+MgB2) in the MgB2 superconducting wire sample is calculated; and β3 is the volume ratio of the Nb tube to MgB2 in the MgB2 superconducting wire sample. The basis-to-superconductor ratio β of the MgB2 superconducting wire is then calculated by combining the above volume ratios with the sample cross-sectional area.

[0051] Obtain a MgB2 superconducting wire sample; cut a section from the MgB2 superconducting wire to be measured as the MgB2 superconducting wire sample.

[0052] The volume ratio of the external stabilizer Monel to all internal components (Cu+Nb+MgB2) of the MgB2 superconducting wire sample was obtained. The volume ratio of the external stabilizer Monel to all internal components (Cu+Nb+MgB2) of the MgB2 superconducting wire was calculated as follows:

[0053]

[0054] In the formula, ρ M ρ is the resistivity of the Monel alloy in the MgB2 superconducting wire sample; L is the length of the voltage gap in the MgB2 superconducting wire sample; X R represents the overall resistivity of the Monel body, the external stabilizer of the MgB2 superconducting wire, and all its internal components (Cu+Nb+MgB2). m S represents the total resistance of the wire; S is the cross-sectional area of ​​the MgB2 superconducting wire sample. A mathematical model is established for the volume ratio β2 of the external stabilizer Monel and all its internal components (Cu+Nb+MgB2) of the MgB2 superconducting wire: The MgB2 superconducting wire is considered as two parts, one being Monel and the other being all its internal components (Cu+Nb+MgB2), treated as a whole, and β2 is calculated based on the parallel principle.

[0055] Obtain the volume ratio of oxygen-free copper to (Nb+MgB2) in the dispersion stabilizer of the MgB2 superconducting wire sample; the volume ratio of oxygen-free copper to (Nb+MgB2) in the dispersion stabilizer of the MgB2 superconducting wire sample is calculated as follows:

[0056]

[0057] In the formula, ρ Cu ρ is the resistivity of oxygen-free copper in the MgB2 superconducting wire sample; L is the length of the voltage gap in the MgB2 superconducting wire sample; Y The overall resistivity of oxygen-free copper and (Nb+MgB2) in the dispersion stabilizer of the MgB2 superconducting wire sample; ρ X Monel, the external stabilizer of MgB2 superconducting wire, and all its internal components

[0058] The overall resistivity of (Cu+Nb+MgB2). The calculation of the volume ratio β1 of the oxygen-free copper dispersion stabilizer to (Nb+MgB2) in the MgB2 superconducting wire sample: considering all components inside the Monel of MgB2 as a dispersed and stable superconductor, the volume ratio β1 of the dispersed and stable oxygen-free copper to the superconducting region is derived based on the parallel principle.

[0059] Obtain the volume ratio of Nb tubes to MgB2 in the MgB2 superconducting wire sample; β3 is the volume ratio of Nb tubes to MgB2 in the MgB2 superconducting wire sample. If all Nb tubes are the same, then β3 is a constant value.

[0060] Obtain the cross-sectional area of ​​the MgB2 superconducting wire sample; the cross-section of the MgB2 superconducting wire sample is as follows: Figure 6 As shown, when measuring the cross-sectional area of ​​a MgB2 superconducting wire sample, the cross-sectional dimensions of the MgB2 superconducting wire sample are measured first, and then the cross-sectional area is determined based on the cross-sectional dimensions.

[0061] The MgB2 superconducting wire base-superconductor ratio was determined based on the mathematical model, cross-sectional area, volume ratio of the external stabilizer Monel to all its internal components (Cu+Nb+MgB2), volume ratio of the dispersed stabilizer oxygen-free copper to (Nb+MgB2), and volume ratio of Nb tube to MgB2.

[0062] In this invention, ρ in formulas (2) and (3) Cu ρ Y ρ M and ρ X The specific method of obtaining it includes the following steps:

[0063] Step 1: Measure the resistance of oxygen-free copper in the MgB2 superconducting wire sample as a function of temperature, and calculate the fitted value ρ. Cu The relationship between temperature and temperature is calculated using the following formula:

[0064] ρ Cu =ρ Cu_293K ×(1+A1×(T-293)) (4),

[0065] In the formula, ρ Cu The resistivity (mΩ*mm) of oxygen-free copper in the MgB2 superconducting wire sample; ρ Cu_293KA1 is the resistivity (mΩ*mm) of oxygen-free copper in the MgB2 superconducting wire sample at 293K; A1 is the temperature coefficient of resistivity of oxygen-free copper in the MgB2 superconducting wire sample; T is the temperature (273K~315K).

[0066] Step 2: Measure the overall resistivity of the oxygen-free copper and (Nb+MgB2) dispersion stabilizer in the MgB2 superconducting wire sample as a function of temperature, and calculate the fitted value ρ. Y The relationship between temperature and temperature is calculated using the following formula:

[0067] ρ Y =ρ Y_293K ×(1+A2×(T-293)) (5),

[0068] In the formula, ρ Y The overall resistivity (mΩ*mm) of oxygen-free copper and (Nb+MgB2) in the dispersion stabilizer of the MgB2 superconducting wire sample; ρ Y_293K A1 represents the resistivity (mΩ*mm) of the oxygen-free copper dispersion stabilizer and (Nb+MgB2) as a whole in the MgB2 superconducting wire sample at 293 K; A2 represents the temperature coefficient of resistivity of the oxygen-free copper dispersion stabilizer and (Nb+MgB2) as a whole in the MgB2 superconducting wire sample; T represents the temperature (273 K~315 K).

[0069] Step 3: The resistivity of the Monel alloy sample of the MgB2 superconducting wire is calculated using the following formula:

[0070] ρ M =0.482mΩ*mm (6);

[0071] Step 4: Take a MgB2 superconducting wire sample with a known β2 as a standard sample, measure the specifications of the standard MgB2 superconducting wire sample, measure the change in resistance of the standard MgB2 superconducting wire sample with temperature, and calculate and fit the overall resistivity ρ of all components inside the Monel alloy to obtain the overall resistivity ρ. X The relationship between temperature and temperature is calculated using the following formula:

[0072] ρ X =ρ X_293K ×(1+A3×(T-293)) (7), where ρ X The resistivity (mΩ*mm) of the Monel body, the external stabilizer of the MgB2 superconducting wire, and all its internal components (Cu+Nb+MgB2); ρ X_293K A1 is the resistivity (mΩ*mm) of the Monel body, the external stabilizer of the MgB2 superconducting wire, and all its internal components (Cu+Nb+MgB2) at 293 K; A2 is the temperature coefficient of resistivity of the Monel body, the external stabilizer of the MgB2 superconducting wire, and all its internal components (Cu+Nb+MgB2); T is the temperature (273 K~315 K).

[0073] Feasibility analysis

[0074] To accurately calculate the base-to-superconductor ratio (BTR), the BTR test method of this application is applied to the production BTR test. This requires accurate measurement of the MgB2 superconducting wire sample length L, cross-sectional area S, ambient temperature T, and total resistance Rm of the L-meter MgB2 superconducting wire sample. The following methods are used to measure the relevant parameters and calculate the BTR.

[0075] Length L of MgB2 superconducting wire sample: Measure the length of the MgB2 superconducting wire sample with a steel ruler, accurate to 1 mm;

[0076] The cross-sectional area S of the MgB2 superconducting wire sample: Measure the wire diameter (length, width) of the MgB2 superconducting wire sample using a micrometer, accurate to 0.001 mm;

[0077] Temperature T of MgB2 superconducting wire sample: Use a Lakeshore thermometer and its matching temperature monitor with an accuracy of 30 mK or higher;

[0078] The total resistance Rm of the MgB2 superconducting wire sample was measured using the four-lead method (e.g., Figure 4 The resistance Rm of a L-meter MgB2 superconducting wire sample was measured; a 2182 nanovoltmeter was used for voltage acquisition, with an accuracy of 20 nV, and the measurement accuracy of Rm was 20 nΩ.

[0079] After measuring the parameters L, S, T, and Rm, these four parameters are substituted into formulas (2) and (3) to calculate β2 and β1. Substituting β2, β1, β3 and the cross-sectional area S of the MgB2 superconducting wire sample into formula (1) allows for the calculation of the basis-superconducting ratio of the MgB2 superconducting wire sample. The method of this application is feasible.

[0080] Validity Proof

[0081] Ten MgB2 samples were taken, and the resistivity test of the basis-superconductivity ratio and the paper weighing method were performed on the ten MgB2 superconducting wire samples respectively. The test data are compared as follows: Figure 5 The data is shown in Table 1;

[0082] Table 1

[0083]

[0084] According to Table 1, Figure 5 It can be seen that for MgB2 superconducting wires, the error in the comparison between the test results of the method of the present invention and the paper weighing method for the base-superconducting ratio all falls within 4%.

[0085] Example

[0086] Prepared measuring fixtures:

[0087] —A fixed-length tooling unit measuring 1 meter;

[0088] —Outer diameter micrometer;

[0089] ——2182ANANOVOLTMETER (Nanovolter);

[0090] —2000MULTIMETER (Multifunction Digital Multimeter);

[0091] —KEPCO PROGRAMMABLE POWER SUPPLY;

[0092] ——211 Temperature monitor;

[0093] ——DT670 (thermometer);

[0094] MgB2 superconducting wire sample selection and testing: A 1.5-meter sample of MgB2 superconducting wire was taken. The basis-to-superconductivity ratio β was measured and calculated using the method of this invention. The relevant parameters are measured as follows:

[0095] —The MgB2 superconducting wire sample is clamped on a 1-meter fixed-length fixture, i.e., the length L = 1000 mm;

[0096] —The length and width of the MgB2 superconducting wire sample were measured with a micrometer, and the cross-sectional area of ​​the MgB2 superconducting wire sample was found to be S = 0.795 mm². 2 ;

[0097] —The ambient temperature measured using a DT670 thermometer and a 211 Temperature monitor is T = 296.64 K;

[0098] —A current of 1A was given by a current source, the current was collected by a 2000 digital multimeter, and the voltage of the MgB2 superconducting wire sample was collected by a 2182 nanovoltmeter. The resistance of the MgB2 superconducting wire sample was measured to be Rm = 56.897mΩ using the four-lead method.

[0099] Substituting the temperature T = 296.64 K into formulas (4), (5), and (7) yields the temperature at this temperature.

[0100] ρ Cu =0.018mΩ*mm, ρ Y =0.363mΩ*mm, ρ X =0.033mΩ*mm, Monel's resistivity ρ M=0.482mΩ*mm. The measured parameters of these four resistivities and the MgB2 superconducting wire sample are: length L = 1000mm, resistance Rm = 56.897mΩ, and cross-sectional area S = 0.795mm². 2 Substituting the temperature T = 296.64 K into formulas (2), (3), and (1), the base-to-super ratio β = 5.636 is calculated. The copper ratio of this sample measured by the paper weighing method is 5.667. The percentage error between the test results of the present invention method and the test results of the paper weighing method is -0.55%, which is within 4% and meets the usage requirements.

[0101] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention, and no reference numerals in the claims should be construed as limiting the scope of the claims.

[0102] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for measuring the resistance of MgB2 superconducting wire-superconductor ratio, characterized in that, Includes the following steps: A mathematical model is established for the ratio of MgB2 superconducting wire to superconducting wire, as well as the ratio of cross-sectional area to volume. The mathematical model is as follows: （1）， In the formula, β The basis-to-superconductivity ratio of MgB2 superconducting wire; S The cross-sectional area of ​​the MgB2 superconducting wire sample; β 2 represents the volume ratio of the Monel body, the external stabilizer of the MgB2 superconducting wire, to all its internal components (Cu+Nb+MgB2); β 1 represents the volume ratio of oxygen-free copper to (Nb+MgB2) in the dispersion stabilizer of the MgB2 superconducting wire sample. β 3 represents the volume ratio of Nb tubes to MgB2 in the MgB2 superconducting wire sample; Obtain MgB2 superconducting wire samples; Obtain the volume ratio of the outer stabilizer Monel of the MgB2 superconducting wire sample to all its internal components (Cu+Nb+MgB2); Obtain the volume ratio of oxygen-free copper to (Nb+MgB2) in the dispersion stabilizer of the MgB2 superconducting wire sample; Obtain the volume ratio of Nb tube to MgB2 in the MgB2 superconducting wire sample; Obtain the cross-sectional area of ​​the MgB2 superconducting wire sample; The MgB2 superconducting wire base-superconductor ratio is determined based on the mathematical model, cross-sectional area, volume ratio of the external stabilizer Monel to all its internal components (Cu+Nb+MgB2), volume ratio of the dispersed stabilizer oxygen-free copper to (Nb+MgB2), and volume ratio of Nb tube to MgB2.

2. The resistance measurement method for MgB2 superconducting wire-superconductor ratio according to claim 1, characterized in that: The volume ratio of the outer stabilizer Monel of the MgB2 superconducting wire to all its internal components (Cu+Nb+MgB2) is calculated as follows: （2）， In the formula, ρ M The resistivity of the Monel alloy in the MgB2 superconducting wire sample is given in mΩ×mm. L The length of the voltage gap between the MgB2 superconducting wire samples is in mm; ρ X The resistivity of the Monel body, the external stabilizer of the MgB2 superconducting wire, and all its internal components (Cu+Nb+MgB2) is mΩ×mm. R m The total resistance of the wire is given in mΩ. S The cross-sectional area of ​​the MgB2 superconducting wire sample is in mm². 2 .

3. The resistance measurement method for MgB2 superconducting wire-superconductor ratio according to claim 1, characterized in that: The volume ratio of oxygen-free copper to (Nb+MgB2) in the dispersion stabilizer of the MgB2 superconducting wire sample is calculated as follows: （3）， In the formula, ρ Cu The resistivity of oxygen-free copper in the MgB2 superconducting wire sample is mΩ×mm; L The length of the voltage gap between the MgB2 superconducting wire samples is in mm; ρ Y The overall resistivity of oxygen-free copper and (Nb+MgB2) in the dispersion stabilizer of the MgB2 superconducting wire sample is mΩ×mm; ρ X The resistivity of the Monel body, the external stabilizer of the MgB2 superconducting wire, and all its internal components (Cu+Nb+MgB2) is mΩ×mm.

4. The resistance measurement method for MgB2 superconducting wire-superconductor ratio according to claim 1, characterized in that: The β 3 represents the volume ratio of Nb tubes to MgB2 in the MgB2 superconducting wire sample. All Nb tubes are identical. β 3 is a constant.

5. A method for measuring the resistance of MgB2 superconducting wire-superconductor ratio according to claim 2 or 3, characterized in that: In formula (2) or (3) ρ Cu , ρ Y , ρ M and ρ X The specific method of obtaining it includes the following steps: Step 1: Measure the resistance of oxygen-free copper in the MgB2 superconducting wire sample as a function of temperature, and calculate the fitted result. ρ Cu The relationship between temperature and temperature is calculated using the following formula: （4）， In the formula, The resistivity of oxygen-free copper in the MgB2 superconducting wire sample is mΩ×mm; The resistivity of oxygen-free copper in the MgB2 superconducting wire sample at 293 K is mΩ×mm; A 1 represents the temperature coefficient of resistivity of oxygen-free copper in the MgB2 superconducting wire sample. T The value is for temperature, ranging from 273K to 315K. Step 2: Measure the overall resistivity of the oxygen-free copper and (Nb+MgB2) dispersion stabilizer in the MgB2 superconducting wire sample as a function of temperature, and calculate the fitted result. ρ Y The relationship between temperature and temperature is calculated using the following formula: （5）， In the formula, The overall resistivity of oxygen-free copper and (Nb+MgB2) in the dispersion stabilizer of the MgB2 superconducting wire sample is mΩ×mm; The resistivity of the oxygen-free copper and (Nb+MgB2) aggregate, which are the dispersion stabilizers of the MgB2 superconducting wire sample, at 293 K, is mΩ×mm; A 2 represents the temperature coefficient of overall resistivity of oxygen-free copper and (Nb+MgB2) in the dispersion stabilizer of the MgB2 superconducting wire sample; T is the temperature, ranging from 273K to 315K. Step 3: The resistivity of the Monel alloy sample of the MgB2 superconducting wire is calculated using the following formula: ρ M =0.482mΩ×mm(6); Step 4: Select a known β Using a MgB2 superconducting wire sample as a standard, the resistivity of the standard MgB2 superconducting wire sample was measured to its specifications. The change in resistivity of the standard MgB2 superconducting wire sample with temperature was measured, and the overall resistivity of all components inside the Monel alloy was calculated and fitted. ρ X The relationship between temperature and temperature is calculated using the following formula: （7）， In the formula, The resistivity of the Monel body, the external stabilizer of the MgB2 superconducting wire, and all its internal components (Cu+Nb+MgB2) is mΩ×mm. The resistivity of the Monel body, the external stabilizer of the MgB2 superconducting wire, and all its internal components (Cu+Nb+MgB2) at 293 K, in mΩ×mm; A 3 represents the temperature coefficient of resistivity of the Monel body, the external stabilizer of the MgB2 superconducting wire, and all its internal components (Cu+Nb+MgB2); T is the temperature, ranging from 273K to 315K.

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