Method and system for measuring elasticity modulus of polished rice

Abstract

The invention relates to the technical field of grain mechanical property testing, and discloses a polished rice elasticity modulus measuring method and system.The method comprises the steps that a polished rice sample is obtained, and a natural fracture surface is prepared on the polished rice sample; aiming at the natural fracture surface of the polished rice sample, preparing a micro-column by utilizing a focused ion beam-scanning electron microscope; performing a nanoindentation test on the micro-column to obtain a load-displacement curve of the micro-column; according to the load-displacement curve of the micro-column, an elastic model of the micro-column is obtained and serves as the elastic modulus of the polished rice sample. Through combination of liquid nitrogen freezing fracture, FIB-SEM micromachining technology and micro-nano indentation testing, the real microstructure of polished rice can be reserved to the maximum extent, machining damage can be reduced, targeted mechanical testing on a specific microscopic area of the polished rice on the nanoscale is achieved, the testing precision is high, repeatability is good, and the method is suitable for large-scale popularization and application. Accurate micromechanics data support can be provided for rice processing technology optimization, quality evaluation and variety screening.

Description

Technical Field

[0001] This invention relates to the field of grain mechanical property testing technology, and in particular to a method and system for measuring the elastic modulus of polished rice. Background Technology

[0002] The elastic modulus of polished rice is a core mechanical parameter reflecting its processing tolerance, cooking quality, and storage stability. Accurate measurement of this parameter is crucial for optimizing rice processing techniques and improving product quality. Traditional methods for testing the mechanical properties of polished rice often employ macroscopic compression tests, such as using a hardness tester to apply pressure to individual rice grain samples. While this method is simple to operate, it has low spatial resolution and cannot reflect the relationship between the microstructure of polished rice (such as starch grain arrangement and cell wall distribution) and its mechanical properties.

[0003] With the development of micro-nano testing technology, micropillar compression testing has become an effective means of characterizing the microscopic mechanical properties of materials. It enables precise "point-to-point" mechanical testing by preparing microscale samples. Focused ion beam scanning electron microscopy (FIB-SEM) combines high-resolution imaging with nanoscale fabrication capabilities, allowing for the preparation of micro-nano structures of specific sizes under real-time monitoring. It has been widely applied in the preparation of micro-samples for biomaterials and MEMS materials. However, as a porous and heterogeneous biomaterial, polished rice exhibits complex surface morphology upon natural fracture and is prone to structural damage during microfabrication. Currently, there is a lack of standardized methods for preparing micropillars and measuring the elastic modulus of polished rice specifically tailored to its characteristics.

[0004] While nanoindentation technology has been used to measure the elastic modulus of cement-based and other composite materials, there are few reports on its application in the study of polished rice in combination with FIB-SEM micromachining. Some patents on grain mechanical testing focus on the detection of the compressive strength of loose grains, without involving precise characterization at the microscale; and the reported measurements of the elastic modulus of polished rice mostly use macroscopic compression methods, which have the problems of limited testing scale and insufficient representativeness of results. Summary of the Invention

[0005] This invention provides a method and system for measuring the elastic modulus of polished rice, in order to overcome the shortcomings of the prior art.

[0006] This invention provides a method for measuring the elastic modulus of polished rice, comprising:

[0007] Obtain polished rice samples, wherein the polished rice samples have natural fracture surfaces; Micropillars were prepared using focused ion beam scanning electron microscopy to target the natural fracture surfaces of polished rice samples. Nanoindentation tests were performed on the micropillars to obtain their load-displacement curves. Based on the load-displacement curve of the micropillar, the elastic model of the micropillar is obtained, which is used as the elastic modulus of the refined rice sample.

[0008] According to a method for measuring the elastic modulus of polished rice provided by the present invention, obtaining a polished rice sample includes: Natural fracture surfaces were prepared on polished rice samples using a liquid nitrogen cryo-shock method. A platinum protective layer was deposited on the surface of the rice sample.

[0009] According to the present invention, a method for measuring the elastic modulus of polished rice is provided, wherein micropillars are prepared using focused ion beam scanning electron microscopy on the natural fracture surface of polished rice samples, comprising: The natural fracture surface of the rice sample was scanned using a focused ion beam scanning electron microscope, and the flat area that met the preset screening conditions was selected as the processing area. A platinum protective layer is deposited on the surface of the processing area using a gas injection system; The processing area is milled in steps using a focused ion beam. First, rough machining is performed to form a cylindrical pit, and then fine machining is performed to obtain a micro-pillar. The microcolumns are swept and cleaned.

[0010] According to the method for measuring the elastic modulus of polished rice provided by the present invention, the height-to-diameter ratio of the prepared micropillar is 2.

[0011] According to the present invention, a method for measuring the elastic modulus of polished rice, wherein the nanoindentation test is performed on the micropillar to obtain the load-displacement curve of the micropillar, includes: The indenter of the nanoindenter is calibrated; Align the center of the pressure head with the center of the top of the micro-column; The pressure head is loaded onto the microcolumn at a preset loading speed until the microcolumn undergoes plastic deformation while avoiding complete fracture, and the load-displacement curve of the microcolumn is collected simultaneously. The pressure head is used to unload the microcolumn at a preset loading speed until the load is zero, while the elastic recovery displacement of the microcolumn is recorded.

[0012] According to the present invention, a method for measuring the elastic modulus of polished rice, wherein obtaining the elastic model of the micropillar based on the load-displacement curve of the micropillar includes: Based on the load-displacement curve of the micropillar, the stress-strain curve of the micropillar is obtained. The elastic modulus of the micropillar was obtained based on its stress-strain curve and used as the elastic modulus of the refined rice sample.

[0013] According to the present invention, a method for measuring the elastic modulus of milled rice, wherein obtaining the stress-strain curve of the micropillar based on its load-displacement curve includes: Based on the load-displacement curve of the micropillar, the load is converted into stress according to the cross-sectional area of ​​the micropillar; Based on the load-displacement curve of the micropillar, the ratio of the displacement of the indenter after subtracting the rigid displacement of the nanoindenter to the original height of the micropillar is used as the strain. The stress-strain curves of the micropillars are obtained based on stress and strain.

[0014] According to the present invention, a method for measuring the elastic modulus of polished rice is provided. The expression for the cross-sectional area of ​​the micro-pillar is: A=πd² / 4, where A represents the cross-sectional area of ​​the micro-pillar and d represents the diameter of the micro-pillar. The expression for stress is: σ = F / A, where σ represents stress and F represents the load on the micro-column; The expression for strain is: ε = δ / h, where ε represents strain, δ represents displacement of the indenter, and h represents height of the micro-column.

[0015] According to the present invention, a method for measuring the elastic modulus of polished rice, wherein obtaining the elastic model of the micropillar based on the load-displacement curve of the micropillar includes: In the stress-strain curve of the micropillar, a linear region of the unloading segment is selected, and the slope of this linear region is obtained by fitting, which is the elastic modulus of the micropillar.

[0016] A method for measuring the elastic modulus of polished rice according to the present invention includes: For rice samples with two or more natural fracture surfaces, the elastic modulus of the micropillars corresponding to each natural fracture surface was obtained. The final elastic modulus of the rice sample is obtained by averaging the elastic moduli of the micropillars corresponding to all natural fracture surfaces.

[0017] The present invention also provides a system for measuring the elastic modulus of polished rice, comprising: The sample acquisition module is used to: acquire polished rice samples and prepare natural fracture surfaces using the liquid nitrogen cryo-impact method; The micropillar preparation module is used to: scan the natural fracture surface of the rice sample using a focused ion beam scanning electron microscope, select the processing area, perform protective deposition on the processing area through a gas injection system, and use an ion beam to perform step-by-step milling on the processing area to prepare micropillars; The nanoindentation testing module is used to: perform nanoindentation testing on micropillars using a nanoindenter to obtain the load-displacement curves of the micropillars; The elastic modulus calculation module is used to obtain the elastic modulus of the micropillar based on its load-displacement curve, and use it as the elastic modulus of the refined rice sample.

[0018] The present invention provides a method and system for measuring the elastic modulus of polished rice, which can bring at least the following beneficial effects: This invention utilizes focused ion beam scanning electron microscopy to prepare standardized micropillars on the naturally fractured surface of polished rice, thereby enabling targeted mechanical testing of the microscopic regions of polished rice. It overcomes the shortcomings of traditional macroscopic compression tests, such as low spatial resolution and inability to reflect differences in microscopic structural mechanics like starch grain arrangement and cell wall distribution, improving the testing resolution to the nanometer scale. This allows for more precise acquisition of the elastic modulus of polished rice at the microscopic scale.

[0019] This invention utilizes a liquid nitrogen cryogenic impact method to prepare natural fracture surfaces, preserving the original microstructure of polished rice to the greatest extent possible. During processing, a platinum protective layer deposition and step-by-step milling processes (rough machining to create the foundation pit followed by fine finishing to form the column) are employed sequentially, significantly reducing damage to the microstructure of the polished rice during FIB processing. This ensures that the micropillars maintain a near-realistic mechanical state during nanoindentation testing, improving the reliability and accuracy of the measurement results.

[0020] This invention integrates FIB-SEM micromachining technology with nanoindentation testing and designs a standardized data processing workflow. This standardized workflow makes the testing process controllable, the results repeatable, and provides good comparability between different batches or varieties of polished rice samples, thus providing a unified methodological basis for the quantitative evaluation of the micromechanical properties of polished rice.

[0021] The microscopic elastic modulus data obtained by this invention can be directly related to the processing tolerance, cooking quality and storage stability of polished rice. It can provide accurate and reliable microscopic mechanical parameter support for the optimization of rice processing technology (such as the control of milling pressure and polishing parameters), the objective evaluation of finished product quality and the screening and breeding of varieties with high resistance to processing damage, and has important practical application value.

[0022] In summary, this invention, by integrating micro-nano processing, nano-indentation, and standardized procedures, achieves high-precision, low-damage, and repeatable measurement of the elastic modulus of the microstructure region of refined rice. It fills the gap in existing standardized testing methods at this scale and is of great significance for promoting technological progress in rice processing and quality control. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0024] Figure 1 This is a flowchart illustrating a method for measuring the elastic modulus of polished rice provided by the present invention.

[0025] Figure 2The image shows the SEM morphology of the naturally fractured rice surface (arrows indicate the micropillar processing area).

[0026] Figure 3 The image shows a SEM image of a rice micropillar processed by FIB-SEM (scale bar is 1 μm).

[0027] Figure 4 The load-displacement curve and elastic segment fitting diagram of the nanoindentation test are shown.

[0028] Figure 5 The SEM image of the compressed rice micropillars is shown (showing elastic recovery characteristics).

[0029] Figure 6 This is a schematic diagram of the structure of a rice elastic modulus measurement system provided by the present invention. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, embodiments of this invention, and should not be construed as limiting the invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention. In the description of this invention, it should be understood that the terminology used is for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0031] Figure 1 This is a flowchart illustrating a method for measuring the elastic modulus of polished rice provided by the present invention. The executing entity of this method can be any applicable terminal-side device or network-side device, such as a rice elastic modulus measuring device.

[0032] See Figure 1 The present invention provides a method for measuring the elastic modulus of polished rice, which may include: S110. Obtain a polished rice sample, wherein the polished rice sample has a natural fracture surface.

[0033] In one embodiment, S110 can select intact, mold-free polished rice grains and prepare natural fracture surfaces using a liquid nitrogen cryo-impact method (see [link]). Figure 2 — Soak polished rice in liquid nitrogen for 10-15 minutes, then remove it and quickly clamp both ends with sterile tweezers to apply shear force, causing the polished rice to break along the natural grain boundaries. Fix the broken polished rice sample on a conductive sample stage, and use an ion sputtering instrument to deposit a platinum (Pt) protective layer with a thickness of 5-10 nm on the sample surface to improve conductivity and reduce damage to the sample from subsequent ion beam processing.

[0034] S120. Micropillars were prepared using focused ion beam scanning electron microscopy to target the natural fracture surfaces of refined rice samples.

[0035] In one embodiment, S120 can be fabricated using a Thermo Scientific Helios 5 CX FIB-SEM instrument (see [link]). Figure 3 Specifically, it includes: I. Positioning and Observation: The polished rice sample was placed into the FIB-SEM chamber and evacuated to a vacuum level of 1×10⁻⁶. -5 Below Pa, the natural fracture surface is scanned and imaged using an electron beam (accelerating voltage 15kV, beam current 1nA), and a flat area without obvious defects (such as cracks or holes) is selected as the processing area. II. Protective Deposition: A 5 μm diameter platinum protective layer is deposited on the surface of the processing area using a gas injection system (GIS-Pt). The deposition parameters are: ion beam acceleration voltage 30 kV, beam current 40 pA, and deposition time 60 s, to prevent sample surface peeling during processing. III. Micropillar Cutting: Step-by-step milling is performed using a focused ion beam (gallium ion source). First, rough machining is performed with a beam current of 9.3 nA to remove excess material around the target area, forming a cylindrical pit with a diameter of approximately 10 μm. Then, the beam current is reduced to 2.5 nA for fine finishing. The dimensions are monitored in real time using SEM. Finally, a micropillar with a diameter of 2 μm and a height of 4 μm is machined, ensuring an aspect ratio of 2 (meeting the processing requirements for micropillar samples in GB / T 44839-2024). IV. Post-processing cleaning: The surface of the micropillars is swept and cleaned using an ion beam with a current of 100pA to remove the redeposited layer remaining from the processing.

[0036] S130. Perform nanoindentation tests on the micropillars to obtain the load-displacement curves of the micropillars (see...). Figure 4 ).

[0037] In one embodiment, S130 can transfer the prepared micropillars to a nanoindenter with integrated SEM (such as a Hysitron TI 980) for compression testing, specifically including: I. Probe Calibration: The diamond flat indenter (10μm in diameter) is calibrated for stiffness using a standard quartz sample to ensure that the load measurement error is less than 1%; II. Positioning and Alignment: Observe and adjust the position of the indenter using SEM to align the center of the indenter with the center of the top of the microcolumn, with the alignment error controlled within 0.1μm; III. Compression test: Set the indenter loading speed to 5nm / s, and stop loading when the micropillar produces 5% plastic deformation (to avoid complete breakage of the micropillar). At the same time, load-displacement curves are collected synchronously at a sampling frequency of 1kHz. IV. Unloading and Recovery: Unload the microcolumn at the same speed until the load is zero, and record the elastic recovery displacement of the microcolumn.

[0038] S140. Based on the load-displacement curve of the micro-pillar, the elastic model of the micro-pillar is obtained, which is used as the elastic modulus of the refined rice sample.

[0039] In one embodiment, S140 can convert the load (F) into stress (σ=F / A) based on the cross-sectional area of ​​the micropillar (A=πd² / 4, where d=2μm); the ratio of the indenter displacement (δ) minus the rigid displacement of the equipment to the original height of the micropillar (h=4μm) is taken as strain (ε=δ / h); the linear region (elastic deformation stage) of the load unloading segment is selected in the stress-strain curve, and the slope of this region is fitted using the least squares method, which is the elastic modulus (E) of the milled rice (see...). Figure 5 ).

[0040] In one embodiment, the present invention can be used to prepare micropillars from two or more different regions of a rice sample and perform parallel nanoindentation tests to obtain the elastic modulus of the micropillar corresponding to each natural fracture surface. The average value of the elastic modulus of the micropillars corresponding to all natural fracture surfaces is taken as the final elastic modulus of the rice sample, ensuring that the relative standard deviation is less than 5%.

[0041] The present invention provides two specific embodiments to further describe the method for measuring the elastic modulus of polished rice provided by the present invention.

[0042] Example 1: Measurement of the elastic modulus of indica rice I. Sample pretreatment: Select whole polished rice of the indica rice variety "Guichao No. 2", soak it in liquid nitrogen for 12 minutes to prepare a natural fracture surface, and then sputter to deposit an 8nm platinum layer; II. Micropillar fabrication: The FIB-SEM processing parameters were: electron beam acceleration voltage 15kV, ion beam roughing current 9.3nA, and finishing current 2.5nA. Three micropillars with a diameter of 2μm and a height of 4μm were fabricated. III. Nanoindentation: The indenter was loaded at a speed of 5 nm / s until the micropillar deformed by 0.2 μm (5% plastic deformation), and the load-displacement curve was collected. IV. Results Calculation: The elastic moduli of the three micropillars were 782 MPa, 805 MPa and 793 MPa, respectively, with an average value of 793 MPa and a relative standard deviation of 1.4%.

[0043] Example 2: Measurement of the elastic modulus of japonica rice I. Sample pretreatment: Select the japonica rice variety "Zhonghua 11", soak it in liquid nitrogen for 15 minutes to prepare a natural fracture surface, and then sputter to deposit a 10nm platinum layer; II. Micropillar preparation and indentation testing: Same parameters as in Example 1; III. Results Calculation: The average elastic modulus was 926 MPa, with a relative standard deviation of 1.1%, which is higher than the test results for indica rice and consistent with the microstructure characteristics of the more compactly arranged starch granules in japonica rice.

[0044] The method for measuring the elastic modulus of polished rice provided by this invention has at least the following advantages compared with the prior art: This invention utilizes focused ion beam scanning electron microscopy (FIB-SEM) to prepare standardized micropillars with a diameter of 2 μm and a height of 4 μm on the naturally fractured surface of polished rice, enabling targeted mechanical testing of the microscopic regions of polished rice. This overcomes the shortcomings of traditional macroscopic compression tests, such as low spatial resolution and inability to reflect differences in microscopic structural mechanics like starch grain arrangement and cell wall distribution, thus improving the testing resolution to the nanometer scale and enabling more precise acquisition of the elastic modulus of polished rice at the microscopic scale.

[0045] This invention utilizes a liquid nitrogen cryogenic impact method to prepare a natural fracture surface, preserving the original microstructure of polished rice to the greatest extent possible. During processing, a platinum protective layer deposition and step-by-step milling processes (rough machining to form a pit followed by fine finishing to form a column) are employed sequentially to significantly reduce damage to the microstructure of polished rice during FIB processing. These measures ensure that the microcolumn maintains a near-realistic mechanical state during testing, improving the reliability and accuracy of the measurement results.

[0046] This invention integrates FIB-SEM microfabrication technology with nanoindentation testing, and designs the process according to the GB / T 44839-2024 microcolumn compression test standard. Furthermore, it optimizes processing parameters, loading strategies, and data processing methods specifically for the characteristics of polished rice as a porous, heterogeneous biomaterial. This standardized process ensures controllable testing, repeatable results, and good comparability between different batches or varieties of polished rice samples, providing a unified methodological basis for the quantitative evaluation of the micromechanical properties of polished rice.

[0047] The microscopic elastic modulus data obtained by this invention can be directly related to the processing tolerance, cooking quality and storage stability of polished rice. It can provide accurate and reliable microscopic mechanical parameter support for the optimization of rice processing technology (such as the control of milling pressure and polishing parameters), the objective evaluation of finished product quality and the screening and breeding of varieties with high resistance to processing damage, and has important practical application value.

[0048] In summary, by integrating micro-nano processing, nano-indentation, and standardized procedures, this invention enables high-precision, low-damage, and repeatable measurement of the elastic modulus of microstructural regions in refined rice. It fills the gap in existing standardized testing methods at this scale and is of great significance for promoting technological progress in rice processing and quality control.

[0049] The rice elastic modulus measurement system provided by the present invention is described below. The rice elastic modulus measurement system described below can be referred to in correspondence with the rice elastic modulus measurement method described above.

[0050] See Figure 6 The present invention provides a system for measuring the elastic modulus of polished rice, which may include: The sample acquisition module is used to: acquire polished rice samples and prepare natural fracture surfaces using the liquid nitrogen cryo-impact method; The micropillar preparation module is used to: scan the natural fracture surface of the rice sample using a focused ion beam scanning electron microscope, select the processing area, perform protective deposition on the processing area through a gas injection system, and use an ion beam to perform step-by-step milling on the processing area to prepare micropillars; The nanoindentation testing module is used to: perform nanoindentation testing on micropillars using a nanoindenter to obtain the load-displacement curves of the micropillars; The elastic modulus calculation module is used to obtain the elastic modulus of the micropillar based on its load-displacement curve, and use it as the elastic modulus of the refined rice sample.

[0051] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention 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 of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for measuring the elastic modulus of polished rice, characterized in that, include: Obtain polished rice samples, wherein the polished rice samples have natural fracture surfaces; Micropillars were prepared using focused ion beam scanning electron microscopy to target the natural fracture surfaces of polished rice samples. Nanoindentation tests were performed on the micropillars to obtain their load-displacement curves. Based on the load-displacement curve of the micropillar, the elastic model of the micropillar is obtained, which is used as the elastic modulus of the refined rice sample.

2. The method for measuring the elastic modulus of polished rice according to claim 1, characterized in that, The process of obtaining the polished rice sample includes: Natural fracture surfaces were prepared on polished rice samples using a liquid nitrogen cryo-shock method. A platinum protective layer was deposited on the surface of the rice sample.

3. The method for measuring the elastic modulus of polished rice according to claim 2, characterized in that, The micropillars were prepared using focused ion beam scanning electron microscopy on the natural fracture surfaces of the rice samples, including: The natural fracture surface of the rice sample was scanned using a focused ion beam scanning electron microscope, and the flat area that met the preset screening conditions was selected as the processing area. A platinum protective layer is deposited on the surface of the processing area using a gas injection system; The processing area is milled in steps using a focused ion beam. First, rough machining is performed to form a cylindrical pit, and then fine machining is performed to obtain a micro-pillar. The microcolumns are swept and cleaned.

4. The method for measuring the elastic modulus of polished rice according to claim 3, characterized in that, The height-to-diameter ratio of the prepared micropillars was 2.

5. The method for measuring the elastic modulus of polished rice according to claim 3, characterized in that, The nanoindentation test on the micropillar to obtain the load-displacement curve of the micropillar includes: The indenter of the nanoindenter is calibrated; Align the center of the pressure head with the center of the top of the micro-column; The pressure head is loaded onto the microcolumn at a preset loading speed until the microcolumn undergoes plastic deformation while avoiding complete fracture, and the load-displacement curve of the microcolumn is collected simultaneously. The pressure head is used to unload the microcolumn at a preset loading speed until the load is zero, while the elastic recovery displacement of the microcolumn is recorded.

6. The method for measuring the elastic modulus of polished rice according to claim 5, characterized in that, The process of obtaining the elastic model of the micropillar based on its load-displacement curve, and using it as the elastic modulus of the refined rice sample, includes: Based on the load-displacement curve of the micropillar, the stress-strain curve of the micropillar is obtained. The elastic modulus of the micropillar was obtained based on its stress-strain curve and used as the elastic modulus of the refined rice sample.

7. The method for measuring the elastic modulus of polished rice according to claim 6, characterized in that, The process of obtaining the stress-strain curve of the micropillar based on its load-displacement curve includes: Based on the load-displacement curve of the micropillar, the load is converted into stress according to the cross-sectional area of ​​the micropillar; Based on the load-displacement curve of the micropillar, the ratio of the displacement of the indenter after subtracting the rigid displacement of the nanoindenter to the original height of the micropillar is used as the strain. The stress-strain curves of the micropillars are obtained based on stress and strain.

8. The method for measuring the elastic modulus of polished rice according to claim 7, characterized in that, The expression for the cross-sectional area of ​​a micropillar is: A = πd² / 4, where A represents the cross-sectional area of ​​the micropillar and d represents the diameter of the micropillar; The expression for stress is: σ = F / A, where σ represents stress and F represents the load on the micro-column; The expression for strain is: ε = δ / h, where ε represents strain, δ represents displacement of the indenter, and h represents height of the micro-column.

9. The method for measuring the elastic modulus of polished rice according to claim 5, characterized in that, The process of obtaining the elastic model of the micropillar based on its load-displacement curve, and using it as the elastic modulus of the refined rice sample, includes: In the stress-strain curve of the micropillar, a linear region of the unloading segment is selected, and the slope of this linear region is obtained by fitting, which is the elastic modulus of the micropillar. For rice samples with two or more natural fracture surfaces, the elastic modulus of the micropillars corresponding to each natural fracture surface is obtained, and the average value of the elastic modulus of all micropillars corresponding to the natural fracture surfaces is taken to obtain the final elastic modulus of the rice sample.

10. A system for measuring the elastic modulus of polished rice, characterized in that, include: The sample acquisition module is used to: acquire polished rice samples and prepare natural fracture surfaces using the liquid nitrogen cryo-impact method; The micropillar preparation module is used to: scan the natural fracture surface of the rice sample using a focused ion beam scanning electron microscope, select the processing area, perform protective deposition on the processing area through a gas injection system, and use an ion beam to perform step-by-step milling on the processing area to prepare micropillars; The nanoindentation testing module is used to: perform nanoindentation testing on micropillars using a nanoindenter to obtain the load-displacement curves of the micropillars; The elastic modulus calculation module is used to obtain the elastic modulus of the micropillar based on its load-displacement curve, and use it as the elastic modulus of the refined rice sample.

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