CN111419203A - High-sensitivity pressure sensor, manufacturing method and intelligent wrist strap - Google Patents

Abstract

The invention discloses a high-sensitivity pressure sensor, a manufacturing method and a smart wristband, wherein the high-sensitivity pressure sensor has a layered structure and includes an upper electrode layer, a sensitive layer and a lower electrode layer in sequence from top to bottom, wherein the The upper electrode layer includes a silk film and a sputtered silver layer, the sensitive layer is a sensitive layer film configured by multi-walled carbon nanotubes, hydrogenated styrene-butadiene block copolymers and cyclohexane, and the lower electrode layer is The electrode layer includes a silk film and a sputtered silver layer; thus, the highly sensitive pressure sensor uses a layered structure, and the resistance change is controlled through the contact area between the sensitive layer and the electrode layer in the middle, the test data is stable, and the materials used are flexible and biological. Good compatibility, so not only high sensitivity, but also suitable for long-term detection of human pulse signals.

Description

Highly sensitive pressure sensor, manufacturing method and smart wristband

technical field

The invention relates to the technical field of sensors, in particular to a highly sensitive pressure sensor, a manufacturing method of the highly sensitive pressure sensor and an intelligent wristband.

Background technique

In the related art, pressure sensors can provide the ability to measure pressure changes, so they are widely used in wearable biomedical detection equipment to measure pressure changes caused by human activities, such as pulse, blood pressure, heartbeat, etc.; Most blood pressure measuring instruments are single-point detection, that is, each reading can only calculate diastolic blood pressure and systolic blood pressure, and cannot measure blood pressure continuously, and airbag inflation and pressure are required during measurement. For users who need to measure blood pressure in real time It is more inconvenient, thereby reducing the user experience.

SUMMARY OF THE INVENTION

The present invention aims to solve one of the technical problems in the above technologies at least to a certain extent. Therefore, an object of the present invention is to provide a highly sensitive pressure sensor, which not only has a simple structure, but also has high sensitivity, which can monitor the pulse signal of the human body in real time, thereby greatly improving the user experience.

The second object of the present invention is to provide a method for manufacturing a highly sensitive pressure sensor, which is simple and low in cost, and can manufacture a highly sensitive pressure sensor with high sensitivity and real-time measurement of human pulse signals.

The third object of the present invention is to provide a smart wristband, which is small in size and light in weight, and can measure the pulse signal of the human body in real time.

In order to achieve the above object, the embodiment of the first aspect of the present invention proposes a highly sensitive pressure sensor. The highly sensitive pressure sensor has a layered structure and includes an upper electrode layer, a sensitive layer and a lower electrode layer in sequence from top to bottom, wherein , the upper electrode layer includes a silk film and a sputtered silver layer, and the sensitive layer is a sensitive layer film configured by multi-walled carbon nanotubes, hydrogenated styrene-butadiene block copolymers and cyclohexane. The lower electrode layer includes a silk film and a sputtered silver layer.

According to the highly sensitive pressure sensor of the embodiment of the present invention, the highly sensitive pressure sensor has a layered structure, including an upper electrode layer, a sensitive layer and a lower electrode layer in order from top to bottom, wherein the upper electrode layer includes a silk film and sputtered silver layer, the sensitive layer is a sensitive layer film configured by multi-walled carbon nanotubes, hydrogenated styrene-butadiene block copolymer and cyclohexane, and the lower electrode layer includes a silk film and a sputtered silver layer; The layer is fixed between the upper electrode layer and the lower electrode layer. When pressure is applied to the silk membrane, the contact area between the sensitive layer and the electrode layer is changed to obtain the pulse signal in real time, thereby improving the user experience.

In order to achieve the above object, a second aspect of the present invention provides a method for manufacturing a highly sensitive pressure sensor, the manufacturing method comprising the following steps: based on multi-walled carbon nanotubes, hydrogenated styrene-butadiene block copolymers and The cyclohexane solution is configured with a sensitive layer solution, and the prepared sensitive layer solution is pulled to form a film to obtain a sensitive layer film; a silk solution is prepared according to water, NaHCO3, silk and LiBr solutions, and the silk solution is quiescent. Placed in a drying box to form a film to obtain a silk film; magnetron sputtering silver on the surface of the silk film to serve as an upper electrode layer and a lower electrode layer; the sensitive layer film is fixed in the middle of the upper electrode layer and the lower electrode layer , to assemble a highly sensitive pressure sensor.

According to the manufacturing method of the highly sensitive pressure sensor in the embodiment of the present invention, the manufacturing method is simple and low in cost, and can manufacture a highly sensitive pressure sensor with high sensitivity and real-time measurement of human pulse signals.

In addition, the manufacturing method of the high-sensitivity pressure sensor proposed according to the above-mentioned embodiments of the present invention may also have the following additional technical features:

Optionally, configuring the sensitive layer solution according to the multi-walled carbon nanotubes, the hydrogenated styrene-butadiene block copolymer and the cyclohexane solution includes the following steps: mixing the multi-walled carbon nanotubes with the cyclohexane solution, and Perform stirring and ultrasonication to obtain a homogeneous solution; add hydrogenated styrene-butadiene block copolymer into the uniform solution, and perform stirring and ultrasonication to obtain a sensitive layer solution.

Optionally, the multi-walled carbon nanotubes account for 15%, the hydrogenated styrene-butadiene block copolymer accounts for 85%, and the cyclohexane solution is 50 ml.

Optionally, after mixing the multi-walled carbon nanotubes with the cyclohexane solution, magnetic stirring is performed for 20 minutes and then ultrasonication is performed for 1.5 to 3 hours, and the ultrasonic power is 300w.

Optionally, after adding the hydrogenated styrene-butadiene block copolymer into the homogeneous solution, magnetic stirring for 20 minutes and then ultrasonication for 3 hours, the ultrasonic power is 300w.

Optionally, prepare silk solution according to water, NaHCO , silk and LiBr solution, comprising the following steps: adding silk and NAHCO to water, mixing and heating, and after repeated rinsing for many times, the degummed silk is obtained and dried; The obtained silk is fully dissolved by adding LiBr solution; the dissolved silk solution is placed in a dialysis bag for dialysis to obtain the final silk solution.

Optionally, the NAHCO of 5g and the silk of 5g are added in 1L of water, mixed and boiled for 30 minutes, rinsed once every 30 minutes, and dried for 3 hours at a temperature of 60 ° after rinsing 3 times; 35ml of mol/L LiBr solution was mixed for 4 hours, and heated at 60°, so that 5g of silk was fully dissolved; the dissolved silk solution was placed in a dialysis bag with a ratio of 3ml:1cm, and a 2cm head was added. The bag is heated and boiled with hot water and filtered for 10-15 minutes to obtain the final silk solution.

Optionally, the sensitive layer solution is pulled by a PDMS block with a rough surface, and the parameters are a descending speed of 1000 um/s, a dipping time of 5 s, a pulling height of 55 mm, a pulling speed of 500 um/s, a residence time of 400 s, and the number of times of pulling. 1 time.

In order to achieve the above objective, an embodiment of the third aspect of the present invention provides a smart wristband, including the above-mentioned highly sensitive pressure sensor.

According to the smart wristband of the embodiment of the present invention, the smart wristband is small in size and light in weight, and can measure the pulse signal of the human body in real time.

Description of drawings

FIG. 1 is a schematic structural diagram of a highly sensitive pressure sensor according to an embodiment of the present invention;

2 is a schematic flowchart of a method for manufacturing a highly sensitive pressure sensor according to an embodiment of the present invention;

3 is a schematic flow chart of preparing a sensitive layer solution according to an embodiment of the present invention;

FIG. 4 is a physical diagram of a smart wristband according to an embodiment of the present invention;

5 is a graph of the original pulse wave signal collected by the highly sensitive pressure sensor according to an embodiment of the present invention;

6 is a pulse wave signal diagram of an original pulse wave after filtering processing according to an embodiment of the present invention;

FIG. 7 is a diagram of an accelerated pulse wave signal after the pulse wave signal undergoes a second difference according to an embodiment of the present invention;

8-9 are comparison diagrams of the measured average blood pressure value and the standard blood pressure value obtained after data sampling of the accelerated pulse wave signal according to an embodiment of the present invention.

Detailed ways

The following describes in detail the embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals refer to the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary, and are intended to explain the present invention and should not be construed as limiting the present invention.

For better understanding of the above technical solutions, exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present invention are shown in the drawings, it should be understood that the present invention may be embodied in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided so that the present invention will be more thoroughly understood, and will fully convey the scope of the present invention to those skilled in the art.

In order to better understand the above technical solutions, the above technical solutions will be described in detail below with reference to the accompanying drawings and specific embodiments.

As shown in FIG. 1 , the highly sensitive pressure sensor of the embodiment of the present invention has a layered structure, including an upper electrode layer 100 , a sensitive layer 200 and a lower electrode layer 300 from top to bottom; wherein the upper electrode layer 100 includes a silk film and sputtering Silver layer, the sensitive layer 200 is a sensitive layer film configured by multi-wall carbon nanotubes, hydrogenated styrene-butadiene block copolymer and cyclohexane, and the lower electrode layer 300 includes a silk film and a sputtered silver layer.

That is to say, the structure of the upper electrode layer and the lower electrode layer of the highly sensitive pressure sensor in this embodiment are the same, and both are composed of a silk film and a sputtered silver layer.

It should be noted that the highly sensitive pressure sensor of the present application uses a layered structure, and the resistance change is controlled through the contact area between the sensitive layer and the electrode layer in the middle, the test data is stable, and the materials used are flexible and biocompatible, so not only the sensitivity It is also suitable for detecting human pulse signal for a long time.

In addition, as shown in FIG. 2 , the present invention also provides a method for manufacturing the above-mentioned high-sensitivity pressure sensor, which includes the following steps:

In step 101, a sensitive layer solution is prepared according to the multi-walled carbon nanotubes, hydrogenated styrene-butadiene block copolymer and cyclohexane solution, and the prepared sensitive layer solution is pulled to form a film to obtain a sensitive layer film.

As an example, firstly, the multi-walled carbon nanotubes are mixed with the cyclohexane solution, and stirred and ultrasonicated to obtain a homogeneous solution; then the hydrogenated styrene-butadiene block copolymer is added into the homogeneous solution and stirred Sonicate to get the sensitive layer solution.

As an example, the multi-walled carbon nanotubes account for 15% by mass, the hydrogenated styrene-butadiene block copolymer accounts for 85% by mass, and the cyclohexane solution is 50 ml.

As an example, after mixing the multi-walled carbon nanotubes with the cyclohexane solution, magnetic stirring is performed for 20 minutes and then ultrasonication is performed for 1.5 to 3 hours, and the ultrasonic power is 300w.

As an example, after adding the hydrogenated styrene-butadiene block copolymer into the homogeneous solution, magnetic stirring is performed for 20 minutes and then ultrasonication is performed for 3 hours, and the ultrasonic power is 300w.

As a specific example, as shown in FIG. 3 , 0.3 g of multi-walled carbon nanotubes (MWCNTs) were first mixed with 70 ml of cyclohexane, followed by magnetic stirring for 20 minutes and then sonicated for 3 hours to make the multi-walled carbon nanotubes (MWCNTs) (MWCNT) was uniformly dispersed in the cyclohexane solution to obtain a uniform solution; then 1.7 g of hydrogenated styrene-butadiene block copolymer was added to the uniform solution, followed by magnetic stirring for 20 minutes and then ultrasonication for 3 hours to prepare A sensitive layer solution is obtained.

It should be noted that, after preparing the sensitive layer solution, since cyclohexane is easy to volatilize, it does not need to stand, and the sensitive layer can be directly formed after pulling.

As a specific example, the sensitive layer solution is pulled by a PDMS block with a rough surface, and the parameters are a descending speed of 1000 um/s, a dipping time of 5 s, a pulling height of 55 mm, a pulling speed of 500 um/s, a residence time of 400 s, and the number of times of pulling. 1 time.

In step 102, a silk solution is prepared according to water, NaHCO3, silk and LiBr solution, and the silk solution is left to stand in a drying box to form a film, so as to obtain a silk film.

As an embodiment, silk and sodium bicarbonate (NAHCO ) are added in water to mix and heat, and after repeated washing for many times, the degummed silk is obtained and dried; the dried silk is added into lithium bromide (LiBr) solution to fully Dissolve; put the dissolved silk solution in a dialysis bag for dialysis to obtain the final silk solution.

As a specific embodiment, at first the NAHCO of 5g and the silk of 5g are added in 1L of water and mixed and boiled for 30 minutes, rinsed once every 30 minutes, rinsed 3 times and placed at 60 ° of temperature and dried for 3 hours; then get 5g and dry The silk was mixed with 35ml of 9.3mol/L LiBr solution for 4 hours, and heated at 60° to fully dissolve 5g of silk; finally, the dissolved silk solution was placed in a dialysis bag with a ratio of 3ml:1cm , add a 2cm head bag and heat it with hot water to boil for 10-15min and filter to obtain the final silk solution.

It should be noted that the prepared silk solution needs to be kept chilled; in addition, the prepared silk solution needs to be placed in a drying box of 25 degrees for 24 hours before the silk film can be formed.

Step 103, magnetron sputtering silver on the surface of the silk film to serve as the upper electrode layer and the lower electrode layer.

In step 104, the sensitive layer film is fixed between the upper electrode layer and the lower electrode layer to assemble a highly sensitive pressure sensor.

It should be noted that the assembled highly sensitive pressure sensor from top to bottom is the silk film, the sputtered silver layer, the sensitive layer, the sputtered silver layer and the silk film. When the pressure is applied to the upper silk film, the sensitive layer will be changed. The contact area between the carbon tube and the silver electrode.

As an example, the high-sensitivity pressure sensor uses conductive silver paste to adhere two wires at both ends of the electrode. The conductive silver paste should be applied evenly and thinly. If the thickness is too large, the sensitivity of the sensor will decrease, thereby affecting the high-sensitivity pressure sensor itself. performance.

To sum up, according to the manufacturing method of the highly sensitive pressure sensor according to the embodiment of the present invention, the manufacturing method is simple and low in cost, and can manufacture a highly sensitive pressure sensor with high sensitivity and real-time measurement of human pulse signals.

In addition, as shown in FIG. 4 , the present invention also provides a smart wristband, which includes the above-mentioned high-sensitivity pressure sensor.

The intelligent wristband proposed by the present invention collects biological pulse signals through a high-sensitivity pressure sensor and transmits them to a PC, and uses Matlab algorithm to process the pulse signals to calculate the real-time blood pressure value.

It should be noted that since the pulse signal is interfered by external factors such as breathing, movement and instruments during the acquisition process, it has strong noise, and the acquired pulse signal needs to be processed by the back-end data and filtered by The method of denoising and then second difference can obtain an effective accelerated pulse wave signal. The method of calculating the blood pressure value for the distance between each main peak and the next peak of the accelerated pulse wave is also relatively stable, and the characteristic parameters of the pulse wave are simple. It can be divided into three categories: time parameters, area parameters and waveform parameters; the premise of determining these parameters is to accurately identify the characteristic points of the pulse wave; a complete pulse cycle generally contains six characteristic points; it can be widely used in biomedicine and wearable electronic devices.

5 is a graph of the original pulse wave signal collected by the highly sensitive pressure sensor according to an embodiment of the present invention. First, the baseline processing function polytrend function is used to filter out the DC component, and then the band-pass filter is used to filter the noise, so as to obtain FIG. 6 Pulse wave signal diagram shown.

It should be noted that, due to the front-end circuit, the obtained data points can be pin-smoothed using an interpolation function to perform a second differential operation to obtain the accelerated pulse wave signal diagram as shown in FIG. 7 .

In addition, the accelerated pulse wave signal extracted from the pulse wave reflects the change of the force that promotes blood movement; when the heart starts to eject blood, the arterial blood will be pushed into the capillaries, and at this time, the pressure in the capillaries changes rapidly. The first wave peak A of the accelerated pulse wave is formed; the blood entering the capillaries then flows into the venous blood vessels, which is reflected in the formation of a rapid decline stage on the waveform. At the same time, as the venous blood flow increases Large, the venous blood vessels will return a part of the blood back to the capillaries when the force is applied, thereby forming the second peak B; after that, the blood of the capillaries flows into the venous blood vessels, so as to reciprocate for several cycles, and the waveform of the accelerated pulse wave is also will become more gradual as the elastic pressure of the blood vessel decreases; and the time between A and B can reflect the PWTT, where the PWTT value is the distance between the first peak A and the second peak B; and As the pressure increases, the time between A and B also decreases.

Therefore, through the pulse wave signal, it is analyzed and processed, and the pulse transit time is extracted from the accelerated pulse wave after the second difference processing. The peak function findpeaks finds the distance function between the main peak and the next peak to derive the blood pressure value as shown in Figure 8-9.

It should be noted that the distance between the first peak A and the second peak B is the PWTT value by using the peak-seeking function to limit the peak-seeking height. It should be noted that the peak-seeking function will generate an error value. Small data points are removed.

As a specific embodiment, the smart wristband should pay attention to the personal parameter error when performing blood pressure conversion through the PWTT value after the original pulse wave signal collected by the highly sensitive pressure sensor, and the PWTT data and the synchronously obtained blood pressure data perform linear regression For analysis, substitute the formula P=a+b×PWTT to obtain the model of systolic blood pressure (diastolic blood pressure) and PTT.

It should be noted that in the formula P=a+b×PWTT, P is the blood pressure value, a and b are parameters, and PWTT is the distance between the first peak A and the second peak B in the accelerated pulse wave signal; The sphygmomanometer measures the blood pressure twice to obtain two blood pressure values and two PWTT values obtained synchronously. The obtained blood pressure value and PWTT value are correspondingly brought into the formula to obtain two equations, so as to calculate a and b; by Therefore, the obtained a and b can be regarded as fixed values, and according to the above formula, the real-time blood pressure value of the measurer can be obtained by converting only the real-time PWTT value.

To sum up, according to the smart wristband of the embodiment of the present invention, the smart wristband is small in size, light in weight, sensitive and effective in detecting small force, and can measure the human body pulse signal in real time, which greatly improves the user experience.

In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", " Rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", etc. The relationship is based on the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore It should not be construed as a limitation of the present invention.

In addition, the terms "first" and "second" are only used for descriptive purposes, and should not be construed as indicating or implying relative importance or implying the number of indicated technical features. Thus, a feature defined as "first" or "second" may expressly or implicitly include one or more of that feature. In the description of the present invention, "plurality" means two or more, unless otherwise expressly and specifically defined.

In the present invention, unless otherwise expressly specified and limited, the terms "installed", "connected", "connected", "fixed" and other terms should be understood in a broad sense, for example, it may be a fixed connection or a detachable connection , or integrated; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of the two elements or the interaction relationship between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

In the present invention, unless otherwise expressly specified and limited, a first feature "on" or "under" a second feature may include the first and second features in direct contact, or may include the first and second features Not directly but through additional features between them. Also, the first feature being "above", "over" and "above" the second feature includes the first feature being directly above and obliquely above the second feature, or simply means that the first feature is level higher than the second feature. The first feature is "below", "below" and "below" the second feature includes the first feature being directly below and diagonally below the second feature, or simply means that the first feature has a lower level than the second feature.

In the description of this specification, description with reference to the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples", etc., mean specific features described in connection with the embodiment or example , structure, material or feature is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms should not be construed as necessarily referring to the same embodiment or example. Furthermore, the particular features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, those skilled in the art may combine and combine the different embodiments or examples described in this specification.

Although the embodiments of the present invention have been shown and described above, it should be understood that the above-mentioned embodiments are exemplary and should not be construed as limiting the present invention. Embodiments are subject to variations, modifications, substitutions and variations.

Claims (10)

1. The high-sensitivity pressure sensor is characterized by being of a layered structure and sequentially comprising an upper electrode layer, a sensitive layer and a lower electrode layer from top to bottom, wherein the upper electrode layer comprises a silk membrane and a sputtering silver layer, the sensitive layer is a sensitive layer membrane formed by configuring a multi-walled carbon nanotube, a hydrogenated styrene-butadiene block copolymer and cyclohexane, and the lower electrode layer comprises the silk membrane and the sputtering silver layer.

2. A manufacturing method of a high-sensitivity pressure sensor is characterized by comprising the following steps:

preparing a sensitive layer solution according to a multi-walled carbon nanotube, a hydrogenated styrene-butadiene block copolymer and a cyclohexane solution, and pulling the prepared sensitive layer solution to form a film so as to obtain a sensitive layer film;

preparing a silk solution from water, NaHCO3, silk and L iBr solution, and standing the silk solution in a drying oven to form a film to obtain a silk film;

performing magnetron sputtering silver on the surface of the silk film to serve as an upper electrode layer and a lower electrode layer;

and fixing a sensitive layer film between the upper electrode layer and the lower electrode layer to assemble the high-sensitivity pressure sensor.

3. The method for manufacturing the silk flexible electrode as claimed in claim 2, wherein the step of preparing the sensitive layer solution based on the multi-walled carbon nanotube, the hydrogenated styrene-butadiene block copolymer and the cyclohexane solution comprises the following steps:

mixing the multi-walled carbon nano-tube with a cyclohexane solution, and stirring and ultrasonically treating the mixture to obtain a uniform solution;

and adding hydrogenated styrene-butadiene block copolymer into the uniform solution, and stirring and ultrasonically treating to obtain a sensitive layer solution.

4. A method for manufacturing a silk flexible electrode as defined in claim 3, wherein the multi-walled carbon nanotubes are 15% by mass, the hydrogenated styrene-butadiene block copolymer is 85% by mass, and the cyclohexane solution is 50 ml.

5. The method for manufacturing the silk flexible electrode according to claim 3, wherein after the multi-walled carbon nanotubes are mixed with the cyclohexane solution, the mixture is magnetically stirred for 20 minutes and then subjected to ultrasonic treatment for 1.5-3 hours, wherein the ultrasonic power is 300 w.

6. The method for manufacturing the silk flexible electrode as claimed in claim 3, wherein after the hydrogenated styrene-butadiene block copolymer is added into the homogeneous solution, the mixture is magnetically stirred for 20 minutes and then is subjected to ultrasound for 3 hours, and the ultrasound power is 300 w.

7. A method of making a silk flexible electrode as claimed in claim 1, wherein the silk solution is prepared from water, NaHCO3, silk and L iBr solution, comprising the steps of:

adding silk and NAHCO3 into water, mixing and heating, repeatedly washing for multiple times to obtain degummed silk, and drying;

adding L iBr solution into dried silk for fully dissolving;

and (4) putting the dissolved silk solution into a dialysis bag for dialysis to obtain the final silk solution.

8. A method for manufacturing silk flexible electrode as claimed in claim 7, wherein 5g of NAHCO3 and 5g of silk are added into 1L of water to be mixed and boiled for 30 minutes, and washed once every 30 minutes, and after 3 times of washing, the silk is dried for 3 hours at 60 ℃;

mixing 5g of dried silk with 35ml of L iBr solution of 9.3 mol/L for 4 hours, and standing and heating at 60 ℃ to fully dissolve 5g of silk;

placing the dissolved silk solution in a dialysis bag according to the proportion of 3 ml: 1cm, adding 2cm bag, boiling with hot water, and filtering for 10-15min to obtain final silk solution.

9. A silk flexible electrode manufacturing method according to any one of claims 1 to 6, wherein the sensitive layer solution is pulled by using PDMS blocks with rough surfaces, and the parameters are 1000um/s of descending speed, 5s of dipping time, 55mm of pulling height, 500um/s of pulling speed, 400s of staying time and 1 pulling time.

10. A smart wristband comprising a high-sensitivity pressure sensor according to any one of claims 1 to 9.

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