A flexible sensor chip array based on Euler spiral structure

Abstract

The present invention discloses a flexible sensor chip array based on an Euler spiral structure, relating to the field of flexible agricultural sensors. The array comprises: a flexible substrate, a nanosilver layer, a hydrophobic layer, and an Euler spiral sensitive membrane layer, arranged sequentially from bottom to top; the lower surface of the flexible substrate is in contact with the upper surface of the crop, and the upper surface of the Euler spiral sensitive membrane layer is in contact with the surface of the soil being measured; the flexible sensor chip array is a three-dimensional Euler spiral structure formed by vertically stretching a two-dimensional Euler spiral structure upward with its maximum curvature point as its endpoint. The flexible sensor chip array based on the Euler spiral structure provided by the present invention has a standardized and fair curvature and torsional properties. By stretching and torsion, the contact area between the Euler spiral sensitive membrane layer of the flexible sensor chip array and the test ions in the soil can be increased, thereby significantly improving the detection accuracy of soil nutrients; and the flexible sensor chip array is miniaturized.

Description

Technical Field

[0001] The present invention relates to the technical field of agricultural flexible sensors, and in particular to a flexible sensor chip array based on an Euler spiral structure. Background Art

[0002] Protecting my country's food security and promoting increased agricultural production, efficiency, and income hinges on managing the soil effectively. Soil fertility information acquisition technology is fundamental to implementing scientifically formulated fertilization in farmland. Ion-selective electrodes (ISEs) are electrodes with sensitive membranes that selectively respond to ions or molecules. Their specificity and ease of use make them widely used for soil nutrient testing.

[0003] The application of electrochemical methods on ion-selective electrodes is to use the potential difference before and after the sensitive layer, i.e., the ion-selective electrode, and the sensitivity of the ion-selective electrode itself to reflect the concentration of a certain ion in the analyte. In the Nernst equation, the sensitivity can be expressed as the slope of the Nernst equation.

[0004] At present, the application of electrochemistry for real-time monitoring of soil nutrient content is limited to the design, membrane materials, and preparation process of ion electrodes due to equipment limitations. It requires a large amount of reagents and measurement costs, and also has problems such as high preparation cost, easy damage, low accuracy, and cumbersome operation steps. Summary of the Invention

[0005] The purpose of the present invention is to provide a flexible sensor chip array based on an Euler spiral structure to solve the problems of existing sensor equipment such as large size, low measurement accuracy, high cost and complicated operation steps.

[0006] To achieve the above object, the present invention provides the following solutions:

[0007] A flexible sensor chip array based on an Euler spiral structure comprises: a flexible substrate, a nanosilver layer, a hydrophobic layer, and an Euler spiral sensitive membrane layer, arranged in order from bottom to top; the lower surface of the flexible substrate is in contact with the upper surface of the crop, and the upper surface of the Euler spiral sensitive membrane layer is in contact with the surface of the soil being measured;

[0008] The flexible sensor chip array is a three-dimensional Euler spiral structure formed by vertically stretching a two-dimensional Euler spiral structure with the maximum curvature point as the endpoint.

[0009] Optionally, the projection of the flexible sensor chip array in the xoy plane satisfies the functional relationship of a two-dimensional Euler spiral.

[0010] Optionally, when a two-dimensional Euler spiral structure is stretched vertically upward with a point of maximum curvature as an endpoint to form a three-dimensional Euler spiral structure, the Euler spiral rotates clockwise.

[0011] Optionally, the coordinate position of a point on the flexible sensor chip array, the length and width of the flexible sensor chip array, the positional relationship of the helical surfaces, the distance between adjacent helical surfaces and the stretching radius are all functions related to the stretching height.

[0012] Optionally, the radius of curvature of the Euler spiral is in inverse proportional function to the stretched height of the flexible sensor chip array.

[0013] Optionally, as the curvature of the spiral line of the flexible sensor chip array increases, the distance between two adjacent spiral surfaces decreases in an inversely proportional function relationship.

[0014] Optionally, after the flexible sensor chip array is stretched into a three-dimensional Euler spiral structure, spiral lines of different heights have a parallel characteristic, and a linear coefficient of linear regression is -4.157.

[0015] Optionally, the flexible sensor chip array is a centrosymmetric structure.

[0016] Optionally, the width of the flexible sensor chip array is fixed.

[0017] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0018] Water in soil flows in a spiral pattern. The flexible sensor chip array based on the Euler spiral structure provided by the present invention exhibits a standardized and fair curvature and torsional properties. By stretching and twisting, the contact area between the Euler spiral sensitive membrane layer of the flexible sensor chip array and the test ions in the soil is increased, significantly improving the accuracy of soil nutrient detection. Furthermore, the flexible sensor chip array is miniaturized. This invention overcomes the problems of existing sensor equipment, such as large size, high cost, low test accuracy, and cumbersome operation steps. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 A schematic structural diagram of a flexible sensor chip array based on an Euler spiral structure provided by the present invention;

[0021] Figure 2 A partial schematic diagram of a flexible sensor chip array based on an Euler spiral structure provided by the present invention;

[0022] Figure 3 A diagram showing the working system of the flexible sensor chip array based on the Euler spiral structure provided by the present invention;

[0023] Figure 4 This is a working block diagram of the soil field nutrient measurement system composed of a flexible sensor chip array based on an Euler spiral structure provided by the present invention;

[0024] Figure 5 This is a flow chart of the soil field nutrient measurement system composed of a flexible sensor chip array based on an Euler spiral structure provided by the present invention. DETAILED DESCRIPTION

[0025] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0026] The purpose of the present invention is to provide a flexible sensor chip array based on the Euler spiral structure, which can increase the contact area between the sensitive membrane part of the flexible sensor chip array and the test ions in the soil by stretching and twisting, thereby improving the detection accuracy of soil nutrients.

[0027] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0028] like Figure 1-2 As shown, the present invention provides a flexible sensor chip array based on an Euler spiral structure, comprising: a flexible substrate 1, a nanosilver layer 2, a hydrophobic layer 3, and an Euler spiral sensitive film layer 4, arranged in order from bottom to top. The lower surface of the flexible substrate 1 is in contact with the upper surface of the crop, and the upper surface of the Euler spiral sensitive film layer 4 is in contact with the surface of the soil being measured. Because the nanosilver layer 2, the hydrophobic layer 3, and the Euler spiral sensitive film layer 4 are all overlaid on the flexible substrate 1, their length and width are identical. The width of the flexible sensor chip array is fixed, with a thickness of approximately 75 microns. The stretched height of the flexible sensor chip array varies with the depth and thickness of the crop root system.

[0029] like Figure 1As shown, the flexible sensor chip array is a three-dimensional Euler spiral structure formed by vertically stretching a two-dimensional Euler spiral structure with its maximum curvature point as the endpoint. The flexible substrate 1 in this stacked structure ensures that the entire electrode structure fairly and accurately reproduces the curvature radius and other characteristics of the three-dimensional Euler spiral structure. The hydrophobic layer 3 can effectively improve the influence of the "water layer". Due to the tensile strain of the flexible substrate 1, the sensitive film formed by electrochemical means cannot be well integrated with the substrate. After adding the hydrophobic layer 3, the thin film of the flexible substrate 1 is stretched and strained, and the hydrophobic layer 3 breaks into a mesh structure due to the increase in total surface area. This mesh structure can contain sufficient air. Therefore, when water droplets land on the surface of this structure, the air in the grooves can provide a force to support the water droplets and lift them up, thereby improving the hydrophobicity.

[0030] Furthermore, the coordinate position of a point on the flexible sensor chip array, the length and width of the flexible sensor chip array, the positional relationship of the spiral surfaces, the distance between adjacent spiral surfaces, and the stretching radius are all functions related to the stretching height.

[0031] The curvature radius of the Euler spiral is in an inversely proportional functional relationship to the stretched height of the flexible sensor chip array; as the curvature of the spiral of the flexible sensor chip array increases, the distance between two adjacent spiral surfaces decreases in an inversely proportional functional relationship.

[0032] Furthermore, the flexible sensor array is formed by vertically stretching a two-dimensional Euler spiral structure with the maximum curvature point as the endpoint. The Euler spiral rotates clockwise. The projection of the flexible sensor chip array in the xoy plane satisfies the functional relationship of the two-dimensional Euler spiral, and the integral function relationship satisfied in the two-dimensional plane is:

[0033]

[0034]

[0035] An Euler spiral, also known as a Coronet spiral, is a spiral with a fairly regular curvature.

[0036] In this functional relationship:

[0037] (1) {C(x), S(x)} represents the coordinates of a point in the two-dimensional Euler spiral structure;

[0038] (2) The parameter t in the above parametric equation represents the curvature of the Euler spiral at that point in the two-dimensional plane: k(t) = 2t;

[0039] (3) x represents the range of curvature t, x∈(0,∞). When x is infinite, that is, when the curvature of the Euler spiral is infinite,

[0040] (4) The curvature of the spiral starts from zero at the tangent of the straight segment and increases linearly with the length of the curve;

[0041] The functional relationship of the three-dimensional Euler spiral structure is as follows:

[0042]

[0043]

[0044] Z(x)=x

[0045] In this functional relationship:

[0046] (1) {C(x), S(x), Z(x)} represents the coordinates of the point in the three-dimensional Euler spiral structure;

[0047] (2) In the functional relationship satisfied in the three-dimensional plane, Z(x) = x is used to describe the value of the Z axis;

[0048] (3) The parameter t of the parametric equation represents the curvature of the Euler spiral at that point: k(t) = 2t;

[0049] (4) x represents the range of curvature t, x∈(0,∞). When x is infinite, the curvature of the Euler spiral is infinite. x also represents the value of the point on the Z axis, that is, the stretching height of the flexible sensing array of the three-dimensional Euler spiral structure.

[0050] (5) It can be seen from the functional relationship that C(x) and S(x) are both related to x. Therefore, the length of the flexible sensor chip array can be controlled by controlling the stretching height of the flexible sensor chip array.

[0051] Furthermore, after the flexible sensor chip array is stretched into a three-dimensional Euler spiral structure, the spiral lines of different heights are parallel, and the linear regression coefficient is -4.157.

[0052] Proof: The spirals in three-dimensional space are parallel

[0053] Step 1: First, divide the Euler spiral in three dimensions into discrete points, and then use the size rule of the horizontal and vertical coordinates to select the inflection points of any two spirals. It can be deduced that (x0, y0, z0) is the inflection point;

[0054] Similarly, we can get the inflection points (x1, y1, z1) (x2, y2, z2) (x3, y3, z3), where z0>z1>z2>z3, and the four points are the four inflection points taken from top to bottom;

[0055] Step 2: Take the curve between (x0, y0, z0) (x1, y1, z1) to form line L1; take the curve between (x2, y2, z2) (x3, y3, z3) to form line L2;

[0056] Step 3: Construct a linear regression curve y=a+bx;

[0057] Step 4: Regress the two curves and obtain the regression coefficient b = -4.157;

[0058] Therefore, we can get L1∥L2.

[0059] Furthermore, the flexible sensor chip array is a three-dimensional Euler spiral structure formed by stretching a two-dimensional Euler spiral, so the distance between two adjacent spirals can be calculated using the equation of the two-dimensional Euler spiral.

[0060] Proof: The distance between two adjacent spirals of an Euler spiral is: d = R1-R2;

[0061] Step 1: For the Euler spiral, the curvature K = 1 / R;

[0062] Step 2: From the definition of Euler spiral, we know that curvature K = 1 / 2t;

[0063] Step 3: From step 2, we know that R = 2t;

[0064] Step 4: From this we can get: the distance between the two spirals d = 2(t1-t2).

[0065] Furthermore, after being stretched into a three-dimensional Euler spiral structure, the flexible sensor chip array is a centrally symmetrical structure.

[0066] Prove that the Euler spiral in a known two-dimensional plane is a centrosymmetric structure, and verify whether the three-dimensional Euler spiral structure has a centrosymmetric relationship. There are two ways to prove it:

[0067] Method 1 is as follows:

[0068] Step 1: Pick any three points in the three-dimensional Euler spiral structure and determine their coordinates as (x1, y1, z1) (x2, y2, z2) (x3, y3, z3), and then take the coordinates of the points symmetric about the center (-x1, -y1, -z1) (-x2, -y2, -z2) (-x3, -y3, -z3)

[0069] Step 2: Substitute the coordinates of the symmetrical point into the original equation to verify whether it conforms to the functional relationship

[0070] Step 3: Verify that the symmetrical points conform to the original relationship

[0071] Step 4: The three-dimensional Euler spiral structure is symmetrical about the origin.

[0072] Method 2 is as follows:

[0073] Step 1: Use Matlab to draw the three-dimensional Euler spiral;

[0074] Step 2: Sample the continuous Euler spiral at equal intervals to obtain countless discrete points;

[0075] Step 3: Retrieve the coordinates of discrete points and find the centrally symmetric points.

[0076] Step 4: The three-dimensional Euler spiral structure is symmetrical about the origin.

[0077] Furthermore, the stretching height of the flexible sensor chip array when stretched into a three-dimensional Euler spiral structure is x, that is, the range of the parameter t in the three-dimensional Euler spiral structure.

[0078] Proof: The stretching height of the flexible sensor chip array when it is stretched into a three-dimensional Euler spiral structure.

[0079] Step 1: The stretching height of the flexible sensor chip array when it is stretched into a three-dimensional Euler spiral structure, that is, the vertical coordinate value of the highest stretching point on the three-dimensional Euler spiral structure;

[0080] Step 2: From the definition of the three-dimensional Euler spiral structure, we know that: Z(x) = x, so the value of is the stretching height;

[0081] Furthermore, the radius of the flexible sensor chip array before being stretched into a three-dimensional Euler spiral structure is 2t.

[0082] Proof: The radius of the flexible sensor chip array before being stretched into a three-dimensional Euler spiral structure is: 2t;

[0083] Step 1: For the Euler spiral, the curvature K = 1 / R;

[0084] Step 2: From the definition of Euler spiral, we know that curvature K = 1 / 2t;

[0085] Step 3: From step 2, we know that R = 2t;

[0086] Furthermore, the flexible sensor chip array is a three-dimensional Euler spiral structure, and the water migration in the soil is also a spiral in three-dimensional space.

[0087] Soil anions, such as nitrate ions, promote plant growth, while excessive inorganic anions can cause soil salinization. Therefore, exploring the spatial variation of inorganic anions in soil is of great significance for salinization control and ecological restoration. During plant growth, soil anions are transferred along with the movement of water within the soil, providing nutrients for plant growth. The movement of water and salt in soil primarily occurs along the soil's pores. The pores between soil particles vary in size. Smaller pores that function as capillaries are called capillary pores, while larger pores are called non-capillary pores. Water and salt move upward primarily along the soil's capillary pores; downward primarily through non-capillary pores. The three-dimensional spatial variations in soil pores and cracks lead to highly complex and non-uniform soil water flow. Therefore, embodiments of the present invention utilize a flexible sensor chip array with a three-dimensional Euler spiral structure to increase the contact area between the soil and the sensitive membrane layer, thereby improving detection accuracy and stability.

[0088] Furthermore, the flexible sensor chip array has a three-dimensional spiral structure. The flexible sensor array is wrapped around the crops to be measured longitudinally and transversely respectively. The ion concentration inside and outside the sensitive membrane layer of the flexible sensor chip array is inconsistent. Ion exchange occurs between the nitrate in the soil and the sensitive membrane of the flexible sensor chip array. When the transfer of charged ions reaches equilibrium, a potential difference, namely the membrane potential, is generated on both sides of the sensitive membrane of the flexible sensor chip array. The flexible sensor chip array is prepared by electrochemical methods, and the potential difference is measured by a 55 ion meter.

[0089] During electrochemical sensing, the potential difference between the working electrode and the reference electrode can directly reflect the change in ion concentration in the solution. The measured potential is defined by the Nernst equation:

[0090]

[0091] Among them, E 0 is the standard potential of the electrode, which is a constant; n is the number of electrons involved in the electrochemical reaction; R is the gas constant, which is 8.314 J / (Kmol); T is the absolute temperature, which is t+273.15K; F is the Faraday constant, which is 96487C / mol; NO3 - Indicates the chloride ion concentration (mol / L).

[0092] It can be seen from the above formula that the potential of the working electrode is proportional to the concentration of nitrate ions. The response range of the flexible sensor chip array to nitrate ions is: 10 -7 mol / L~10 -1 mol / L.

[0093] Furthermore, the flexible sensor chip array can measure the nutrient content of two diagonally opposite parts of the soil. With long-term cultivation, the soil has far lost its healthy state. Soil testing is a key link in soil testing and fertilization. Whether before cultivation, before fertilization or during cultivation, the soil must be tested in detail to obtain accurate test data. The accuracy of soil testing is closely related to sampling. The more standardized the sampling, the more accurate the test results. For a piece of land, the quartering method is generally used for standard soil sampling. Divide the soil sample into four, keep the diagonal soil sample, and remove the other soil samples. The soil sample on the diagonal can represent the soil nutrient status of the entire piece of land. The flexible sensor chip array has a central symmetrical structure and can be placed on the diagonal soil sample of a piece of land to monitor nutrients, and the monitoring results are convincing and accurate.

[0094] like Figure 3-Figure 4 As shown, the soil field nutrient measurement system composed of the flexible sensor chip array provided in the embodiment of the present invention is mainly composed of hardware and software systems. The hardware system mainly includes an electrode detection platform and a data acquisition system. The preparation parameters of the relevant electrodes, monitoring parameters and collected soil nutrient data will be converted into analog and digital data and serial communication will be performed by the data acquisition system and finally displayed on the PC end.

[0095] like Figure 5 The following diagram illustrates the main workflow of a soil field nutrient measurement system comprised of a flexible sensor chip array according to an embodiment of the present invention. The system initializes, accepting serial port commands. The device's power supply and valves begin operating to extract soil leachate. The device then measures the nutrients in the soil leachate, performing data collection, processing, and storage on the computer. The serial port then transmits the data to the PC for display, completing the collection of a set of soil nutrient data. If further monitoring is no longer necessary, simply exit the system.

[0096] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only intended to help understand the method and core concept of the present invention. At the same time, those skilled in the art will find that the specific implementation methods and application scopes may vary based on the concept of the present invention. In summary, the contents of this specification should not be construed as limiting the present invention.

Claims

1. A flexible sensor chip array based on an Euler spiral structure, characterized in that: include: The flexible substrate, nanosilver layer, hydrophobic layer and Euler spiral sensitive film layer are arranged in sequence from bottom to top; The lower surface of the flexible substrate is in contact with the upper surface of the crop, and the upper surface of the Euler spiral sensitive membrane layer is in contact with the surface of the soil to be measured; The flexible sensor chip array is a three-dimensional Euler spiral structure formed by vertically stretching a two-dimensional Euler spiral structure with the maximum curvature point as the endpoint; The radius of curvature of the Euler spiral is inversely proportional to the stretched height of the flexible sensor chip array; as the curvature of the spiral of the flexible sensor chip array increases, the distance between two adjacent spiral surfaces decreases inversely proportional to the stretched height of the flexible sensor chip array; after the flexible sensor chip array is stretched into a three-dimensional Euler spiral structure, the spirals at different heights are parallel, and the linear coefficient of linear regression is -4.157; the flexible sensor chip array is a centrally symmetrical structure with a fixed width.

2. The flexible sensor chip array based on the Euler spiral structure according to claim 1, characterized in that: The projection of the flexible sensor chip array in the xoy plane satisfies the functional relationship of a two-dimensional Euler spiral.

3. The flexible sensor chip array based on the Euler spiral structure according to claim 1, characterized in that: When the Euler spiral structure in a two-dimensional plane is stretched vertically upward with the point of maximum curvature as the endpoint to form a three-dimensional Euler spiral structure, the Euler spiral rotates clockwise.

4. The flexible sensor chip array based on the Euler spiral structure according to claim 1, characterized in that: The coordinate positions of points on the flexible sensor chip array, the length and width of the flexible sensor chip array, the positional relationship of the spiral surfaces, the distance between adjacent spiral surfaces and the stretching radius are all functions related to the stretching height.

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