Electronic device and operating method for measuring acoustic nonlinear coefficient of material

Abstract

The present invention relates to an electronic device and an operating method for determining the acoustic nonlinear coefficient of a material, the electronic device comprising: a transmitter that generates an ultrasonic signal; a receiver that receives a reflected wave signal of the ultrasonic signal, the reflected wave signal having been attenuated while passing through the inside of the material; and a processor. The processor is configured to: acquire first attenuation correction information for the attenuation correction of the fundamental harmonic of the reflected wave signal and second attenuation correction information for the attenuation correction of the second harmonic of the reflected wave signal by using the displacement of the reflected wave signal within the material, the displacement being based on the number of reflections of the reflected wave signal at the boundary of the material; and determine the acoustic nonlinear coefficient (β) of the material by using the first attenuation correction information and the second attenuation correction information.

Description

Electronic device and operating method for measuring acoustic nonlinear coefficients of materials

[0001] The present invention relates to an electronic device and an operating method for determining an acoustic nonlinear coefficient of a material, and more particularly, to an electronic device and an operating method for effectively measuring an acoustic nonlinear coefficient by measuring a second harmonic component with a high signal-to-noise ratio (SNR) regardless of the specimen size by artificially generating countless reflected waves inside a material.

[0002]

[0003] Second harmonic generation (SHG), a nonlinear ultrasonic technique, is sensitive to changes in the material microstructure due to acoustic nonlinear coefficients. The demand for non-destructive testing techniques that utilize this technology is increasing, as it enables quantitative analysis of material micro-cracks and damage by measuring them.

[0004] The SHG (second harmonic generation) technique using a general longitudinal wave transmits and receives ultrasonic waves inside the specimen using a tone-burst signal of a sine function with a constant cycle inside the specimen, and performs frequency domain analysis on the collected signal to determine the acoustic nonlinear coefficients. Measures.

[0005] However, in order to minimize interference from surface reflections, a very small number of cycles is allowed when the size of the specimen is small, which causes a problem in that the second harmonic component is not properly measured due to a low signal-to-noise ratio (SNR) caused by band broadening of the frequency domain signal, making it difficult to accurately measure. There are limitations to measurement.

[0006]

[0007] Accordingly, the technical problem that the present invention seeks to solve is that it was created to solve the above-mentioned problem, and overcomes the measurement limitation due to the size of the specimen, so that even for small specimens, The purpose of this invention is to provide an electronic device and an operating method for providing a technology capable of effectively and precisely measuring .

[0008] The technical problems to be solved by the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned can be clearly understood by a person having ordinary skill in the technical field to which the present invention belongs from the description below.

[0009]

[0010] According to the present invention for solving the above technical problem, an electronic device and an operating method for determining an acoustic nonlinear coefficient of a material include a transmitter for generating an ultrasonic signal, a receiver for receiving a reflected wave signal attenuated while the ultrasonic signal is transmitted through the inside of the material, and a processor, wherein the processor obtains first attenuation correction information for attenuation correction of a fundamental harmonic of the reflected wave signal and second attenuation correction information for attenuation correction of a second harmonic of the reflected wave signal by using a travel distance of the reflected wave signal within the material based on a number of reflections of the reflected wave signal at a boundary of the material, and determines an acoustic nonlinearity parameter (ACP) of the material by using the first attenuation correction information and the second attenuation correction information. ) may include an electronic device configured to determine the

[0011]

[0012] The present invention overcomes the limitation of measurement due to the specimen size of the existing methodology and measures the acoustic nonlinear coefficient (regardless of the specimen size) ) has the ability to measure.

[0013] This enables quantitative evaluation of material microstructural changes for small-sized specimens.

[0014] In addition, the present invention can have great expandability in that it can be universally applied to any materials.

[0015] The effects of the present invention are not limited to the effects described above, and the tentative effects expected by the technical features of the present invention can be clearly understood from the description below.

[0016]

[0017] FIG. 1 is a schematic diagram illustrating components of an electronic device according to various embodiments.

[0018] FIG. 2 is a schematic diagram illustrating a method of measuring a nonlinear coefficient of a material using an electronic device according to various embodiments.

[0019] FIG. 3 is a flowchart illustrating a method of operating an electronic device according to various embodiments.

[0020] FIG. 4 is an exemplary diagram illustrating a method of operating an electronic device according to various embodiments.

[0021] FIG. 5 is an exemplary diagram illustrating a method of operating an electronic device according to various embodiments.

[0022] FIG. 6a is a diagram illustrating experimental results showing time domain signals according to thermal damage according to various embodiments.

[0023] FIG. 6b is a diagram illustrating experimental results showing frequency domain signals due to thermal damage according to various embodiments.

[0024] FIG. 7a is a diagram showing changes in longitudinal wave velocity due to thermal damage according to various embodiments.

[0025] FIG. 7b is a diagram showing measured acoustic nonlinear coefficients due to thermal damage and acoustic nonlinear coefficients corrected for superposition effects according to various embodiments.

[0026] Figure 8 is a drawing showing examples of experimental materials according to various embodiments.

[0027] FIG. 9 is an exemplary drawing showing a process of applying thermal damage to a material according to various embodiments.

[0028] FIG. 10a is an exemplary drawing of actual experimental devices according to various embodiments.

[0029] FIG. 10b is a drawing of FIG. 2 implemented as an actual experimental scene according to various embodiments.

[0030] In connection with the description of the drawings, the same or similar reference numerals may be used for identical or similar components.

[0031]

[0032] Hereinafter, various embodiments of the present document will be described with reference to the attached drawings. It should be understood that the embodiments and the terms used therein are not intended to limit the technology described in the present document to a specific embodiment, but rather include various modifications, equivalents, and / or substitutes of the embodiments. In connection with the description of the drawings, similar reference numerals may be used for similar components. The singular expression may include plural expressions unless the context clearly indicates otherwise. In this document, expressions such as "A or B" or "at least one of A and / or B" may include all possible combinations of the items listed together. Expressions such as "first," "second," "first," or "second," may modify the corresponding components regardless of order or importance, and are only used to distinguish one component from another, but do not limit the corresponding components. When it is said that a component (e.g., a first component) is “(functionally or communicatively) connected” or “connected” to another component (e.g., a second component), said component may be directly connected to said other component, or may be connected via another component (e.g., a third component).

[0033] In this document, "configured to" may be used interchangeably with, for example, "suitable for," "capable of," "modified to," "made to," "capable of," or "designed to," either in hardware or software. In some contexts, the phrase "a device configured to" may mean that the device is "capable of" doing something together with other devices or components. For example, the phrase "a processor configured to perform A, B, and C" may mean a dedicated processor (e.g., an embedded processor) for performing the operations, or a general-purpose processor (e.g., a CPU or application processor) that can perform the operations by executing one or more software programs stored in a memory device.

[0034] An electronic device according to various embodiments of the present document may include, for example, at least one of a smartphone, a tablet PC, a desktop PC, a laptop PC, a netbook computer, a workstation, and a server.

[0035] FIG. 1 is a schematic diagram illustrating components of an electronic device according to various embodiments.

[0036] FIG. 2 is a schematic diagram illustrating a method of measuring a nonlinear coefficient of a material using an electronic device according to various embodiments.

[0037] Referring to FIG. 1, in various embodiments, an electronic device (100) may include a transmitter (101), a receiver (102), a processor (103), and a memory (104). In some embodiments, the electronic device (100) may omit at least one of the components or additionally include other components.

[0038] In one embodiment, the transmitter (101) measures the acoustic nonlinear coefficient of the material ( ) can generate an ultrasonic signal for measuring the ultrasonic signal. The transmitter (101) may refer to any type of device or apparatus capable of generating an ultrasonic signal, including a transducer. For example, referring to FIG. 2, the transmitter (101) can generate an ultrasonic signal.

[0039] In one embodiment, the receiver (102) can receive an attenuated reflected wave signal while passing through the interior of the material when the ultrasonic signal from the transmitter (101) is transmitted through the material for measuring the acoustic nonlinear coefficient. For example, referring to FIG. 2, the receiver (102) can receive an attenuated reflected wave signal while passing through the interior of the material (201). The receiver (102) may refer to any type of device or apparatus capable of receiving an ultrasonic signal. According to one embodiment, referring to FIG. 2, the receiver (102) according to the present disclosure can be positioned spaced apart from the material (201), and the electronic device (100) can easily measure the acoustic nonlinear coefficient of a material (201) (e.g., cement paste) having a small size (e.g., 5 x 5 x 5 cm) that was difficult to measure using a conventional method by using the attenuated reflected wave signal.

[0040] In one embodiment, the processor (103) may include one or more of a central processing unit, an application processor, or a communication processor (CP). The processor (103) may, for example, perform operations or data processing related to control and / or communication of at least one other component of the electronic device (100).

[0041] In one embodiment, the memory (104) may include volatile and / or non-volatile memory. The memory (104) may store, for example, instructions or data relating to at least one other component of the electronic device (100).

[0042] The memory (104) may include volatile and / or non-volatile memory. The memory (104) may store, for example, instructions or data related to at least one other component of the electronic device (100). According to one embodiment, the memory (104) may store software and / or programs. The programs may include, for example, a kernel, middleware, an application programming interface (API), and / or an application program (or “application”). At least a portion of the kernel, middleware, or API may be referred to as an operating system.

[0043]

[0044] FIG. 3 is a flowchart illustrating a method of operating an electronic device according to various embodiments.

[0045] FIG. 4 is an exemplary diagram illustrating a method of operating an electronic device according to various embodiments.

[0046] FIG. 5 is an exemplary diagram illustrating a method of operating an electronic device according to various embodiments.

[0047] In operation 301, according to various embodiments, the electronic device (e.g., the processor (103) of FIG. 1) may obtain first attenuation correction information for attenuation correction of the fundamental harmonic of the reflected wave signal and second attenuation correction information for attenuation correction of the second harmonic of the reflected wave signal by using the travel distance of the reflected wave signal within the material based on the number of reflections of the reflected wave signal at the boundary of the material. Here, the harmonic means harmonic, and the fundamental harmonic means the fundamental angular frequency. It means a harmonic wave with a frequency of 2 times the second harmonic wave. It may mean a harmonic wave having . According to one embodiment, the attenuation correction information may be information for correcting the attenuation phenomenon that occurs when an ultrasonic signal generated by a transmitter (101) is dissipated in energy by absorption, reflection, scattering, etc. during the process of transmitting the ultrasonic signal through the inside of a material (201).

[0048] According to one embodiment, the first attenuation correction information and the second attenuation correction information can be expressed by [Mathematical Formula 1].

[0049] [Mathematical Formula 1]

[0050] (1)

[0051] (2)

[0052]

[0053] According to one embodiment, is the first attenuation correction information, is the second attenuation compensation information, is the damping coefficient for the fundamental harmonic frequency, is the damping coefficient for the second harmonic frequency, n is the number of reflections of the reflected wave, and L can represent the thickness of the material.

[0054] 1) According to one embodiment, referring to FIGS. 4 and 5, when a reflection occurs inside the material (201), the wave moves 2L more with respect to the thickness (L) of the material (201) during one reflection, and thus a phase difference of 2Lk may occur. ( this (It is 2Lk longer than that.)

[0055] 2) According to an embodiment, referring to FIGS. 4 and 5, an additional phase difference may occur depending on the acoustic impedance (Z) boundary condition of the material (201). For example, the acoustic impedance relationship of air (A), material (C), and transmitter (T) In this case, the acoustic impedance of air is calculated by [Mathematical Formula 2] Acoustic impedance of material (201) Because it is smaller than the fixed reflection condition, it is reflected. Phase inversion may occur.

[0056] According to one embodiment, is the acoustic impedance of air, is the acoustic impedance of the material (201), can mean the acoustic impedance of the transmitter

[0057] [Equation 2]

[0058] (phase inversion)

[0059]

[0060]

[0061] According to one embodiment, the phase difference of the nth reflected wave is can be expressed as

[0062] In general, the phase difference of the nth reflected wave for the fixed-end reflection number j (= 0 or 1 or 2) during the process of the reflected wave going back and forth once inside the specimen is can be expressed as

[0063] In one embodiment, a step of measuring general acoustic nonlinear coefficients may be added before performing operation 301.

[0064] Specifically, countless reflected waves can be generated inside a material (201) through a transmitter (101), and a superposition signal of the reflected waves can be received through a receiver (102). At this time, the nonlinear wave equation of [Mathematical Formula 4] can be derived through the nonlinear constitutive equation (1) and the one-dimensional motion equation (2) of [Mathematical Formula 3].

[0065] [Equation 3]

[0066] (1)

[0067] (2)

[0068]

[0069] [Equation 4]

[0070]

[0071]

[0072] According to one embodiment, is stress, is strain, is the second-order nonlinear coefficient, can represent the displacement in the x-direction, and c can represent the longitudinal wave velocity.

[0073] Here, the amplitudes of the fundamental harmonic and second harmonic waves can be measured through frequency component analysis of the collected signal. At this time, the harmonic wave equation for the nonlinear wave equation of [Mathematical Equation 4] can be derived as the sum of (1) the displacement of the fundamental harmonic wave and (2) the displacement of the second harmonic wave of [Mathematical Equation 5], and through this, the acoustic nonlinear coefficient can be measured as in [Mathematical Equation 6].

[0074] [Equation 5]

[0075] (1)

[0076] (2)

[0077] [Equation 6]

[0078]

[0079] According to one embodiment, is the fundamental harmonic displacement, is the fundamental harmonic amplitude, is the second harmonic displacement, is the second harmonic amplitude, may represent the fundamental angular frequency, k the fundamental wave number, and x the travel distance of the wave. According to one embodiment, when a wave passes through the inside of a material (201), an attenuation phenomenon may occur in which energy is dissipated by absorption, reflection, scattering, etc., and through the attenuation coefficient of the material, (1) the fundamental harmonic displacement and (2) the second harmonic displacement can be expressed as in [Mathematical Expression 7], and through this, the acoustic nonlinear coefficient with the attenuation effect corrected as in [Mathematical Expression 8] can be measured.

[0080] [Equation 7]

[0081] (1)

[0082] (2)

[0083]

[0084] [Equation 8]

[0085]

[0086] According to one embodiment, is the initial amplitude, is the damping coefficient for the fundamental harmonic frequency, can mean the damping coefficient for the second harmonic frequency.

[0087]

[0088] In operation 303, according to various embodiments, an electronic device (e.g., processor (103) of FIG. 1) can determine an acoustic nonlinear coefficient of a material using the first attenuation correction information and the second attenuation correction information obtained in operation 301.

[0089] According to one embodiment, the basic harmonic information can be calculated using the first attenuation correction information obtained previously by [Mathematical Formula 9], and the second harmonic information can be calculated using the second attenuation correction information obtained previously by [Mathematical Formula 10].

[0090] [Equation 9]

[0091]

[0092]

[0093] [Equation 10]

[0094]

[0095] According to one embodiment, is the basic harmonic information above, is the second harmonic information, is the initial amplitude, is the basic frequency, is the fundamental angular frequency, can represent the acoustic nonlinear coefficient of the above material.

[0096] According to one embodiment, with reference to the above [Mathematical Formula 9], the superposition of countless reflected waves of the fundamental harmonic component of the n-th reflected wave is can be expressed as , which may include the phase difference described above, The reflection process described may include a compensation term for the attenuation effect accumulated as the distance traveled within the sample increases.

[0097] According to one embodiment, with reference to the above [Mathematical Formula 10], the superposition of countless reflected waves of the second harmonic component of the nth reflected wave is can be expressed as , which may include the phase difference described above, An accumulated damping effect correction term described as may be included.

[0098] According to one embodiment, the first amplitude correction information and the second phase correction information for the superposition of the fundamental harmonic wave can be calculated by [Mathematical Formula 11], and the second amplitude correction information and the second phase correction information for the superposition of the second harmonic wave can be calculated by [Mathematical Formula 12].

[0099] [Equation 11]

[0100] (1)

[0101] (2)

[0102] [Equation 12]

[0103] (1)

[0104] (2)

[0105]

[0106] According to one embodiment, is the first amplitude correction information, is the second amplitude correction information, is the first phase correction information, can represent the second phase correction information.

[0107] According to one embodiment, the basic harmonic information can be calculated using the first amplitude correction information and the first phase correction information obtained above by [Mathematical Formula 13], and the second harmonic information can be calculated using the second amplitude correction information and the second phase correction information obtained above by [Mathematical Formula 14].

[0108] [Equation 13]

[0109]

[0110]

[0111] [Equation 14]

[0112]

[0113] According to one embodiment, the equation represented by the above [Equation 9] is a phase equation according to the sum formula of the phaser (a method of describing trigonometric functions as exponential functions according to the Euler formula). ) and amplitude ( ) can be expressed in the form of the above [Mathematical Formula 13], which is a basic harmonic function having a term.

[0114] According to one embodiment, the equation represented by the above [Equation 10] is expressed as a phase ( ) and amplitude ( ) can be expressed in the form of the above [Mathematical Formula 14], which is a basic harmonic function having a term.

[0115] According to one embodiment, the acoustic nonlinear coefficients can be determined using the first amplitude correction information, the second amplitude correction information, the fundamental harmonic information, and the second harmonic information obtained in operation 301 by [Mathematical Formula 15].

[0116] [Equation 15]

[0117]

[0118]

[0119] According to an additional embodiment, an ultrasonic signal having a very large number of cycles is transmitted into a material to form a reflected wave, which is collected, and for each reflected wave component of the collected ultrasonic signal, a phase delay effect term calculated through the ratio of the wavelength to the size of the specimen and acoustic boundary conditions and an attenuation effect term according to an increase in the distance traveled inside the specimen due to reflection are parameterized, and an amplitude correction coefficient that is mathematically solved through superposition of these is derived and applied to the measured acoustic nonlinear coefficient, thereby allowing the acoustic nonlinear coefficient to be precisely measured.

[0120] According to another additional embodiment, when the material is damaged, the wave speed inside the material decreases, causing the phase difference between the reflected waves to change. When the phase difference has a specific relationship with the size of the material, resonance occurs and the specimen vibrates, which To resolve this issue, the spatial distribution of waves can be fixed by adjusting the sound waves to maintain a constant wavenumber within the material, thereby uniformizing the superposition effect and preventing vibration effects due to resonance.

[0121]

[0122] FIG. 6a is a diagram illustrating experimental results showing time domain signals according to thermal damage according to various embodiments.

[0123] FIG. 6b is a diagram illustrating experimental results showing frequency domain signals due to thermal damage according to various embodiments.

[0124] FIG. 7a is a diagram showing changes in longitudinal wave velocity due to thermal damage according to various embodiments.

[0125] FIG. 7b is a diagram showing measured acoustic nonlinear coefficients due to thermal damage and acoustic nonlinear coefficients corrected for superposition effects according to various embodiments.

[0126] Figure 8 is a drawing showing examples of experimental materials according to various embodiments.

[0127] FIG. 9 is an exemplary drawing showing a process of applying thermal damage to a material according to various embodiments.

[0128] FIG. 10a is an exemplary drawing of actual experimental devices according to various embodiments.

[0129] FIG. 10b is a drawing of FIG. 2 implemented as an actual experimental scene according to various embodiments.

[0130] According to various embodiments, referring to FIGS. 6a to 6b and 7a to 7b, 100 for a small-sized material (201) that was difficult to measure using a conventional method , 200 By sequentially applying heat damage at a temperature for 2 hours to generate microcracks and measuring the acoustic nonlinear coefficients using the method described above, the microstructural change of the material (201) can be quantified and analyzed with high sensitivity. Specifically, as in FIG. 8, an example material (201) for measuring the microstructural change can be prepared, and the material (201), transmitter (101), and receiver (102) can be set up as in the drawing of FIG. 10b, and actual experimental devices for measuring this can be prepared as in FIG. 10a, and the acoustic nonlinear coefficient can be measured by applying heat damage to the material (201) as in FIG. 9. This is merely an example, and the size and type of the material, the experimental device, the temperature and time for applying heat damage, etc. are not limited to those mentioned above.

[0131]

[0132] The term "module" or "part" used in this document includes a unit composed of hardware, software, or firmware, and can be used interchangeably with terms such as logic, logic block, component, or circuit, for example. The "module" or "part" can be an integrally configured component or a minimum unit or a part thereof that performs one or more functions. The "module" or "part" can be implemented mechanically or electronically, and can include, for example, an ASIC (application-specific integrated circuit) chip, FPGAs (field-programmable gate arrays), or a programmable logic device, known or to be developed in the future, that performs certain operations, and can be executed by the processor (120). At least a part of the device (e.g., modules or functions thereof) or method (e.g., operations) according to various embodiments can be implemented as instructions stored in a computer-readable storage medium (e.g., memory (130)) in the form of a program module. When the above command is executed by a processor (e.g., processor (120)), the processor can perform a function corresponding to the command. The computer-readable recording medium may include a hard disk, a floppy disk, a magnetic medium (e.g., a magnetic tape), an optical recording medium (e.g., a CD-ROM, a DVD, a magneto-optical medium (e.g., a floptical disk), a built-in memory, etc. The command may include a code generated by a compiler or a code executable by an interpreter. A module or program module according to various embodiments may include at least one or more of the above-described components, some of which may be omitted, or other components may be further included. Operations performed by a module, a program module, or other components according to various embodiments may be executed sequentially, in parallel, iteratively, or heuristically, or at least some operations may be executed in a different order, omitted, or other operations may be added.

[0133] The embodiments disclosed in this document are presented for the purpose of explaining and understanding the disclosed technical content, and do not limit the scope of the present disclosure. Therefore, the scope of the present disclosure should be interpreted to include all modifications or various other embodiments based on the technical concepts of the present disclosure.

Claims

1. In an electronic device for determining the acoustic nonlinear coefficient of a material, a transmitter that generates ultrasonic signals, A receiver that receives an attenuated reflected wave signal as the ultrasonic signal passes through the material, and Contains a processor, The above processor, By using the travel distance of the reflected wave signal within the material based on the number of reflections of the reflected wave signal at the boundary of the material, first attenuation correction information for attenuation correction of the fundamental harmonic of the reflected wave signal and second attenuation correction information for attenuation correction of the second harmonic of the reflected wave signal are obtained, and Using the first attenuation correction information and the second attenuation correction information, the acoustic nonlinear coefficient of the material ( ) is set to determine, Electronic devices.

2. In paragraph 1, The above processor, According to the following [Mathematical Formula 1], the first attenuation correction information and the second attenuation correction information are set to be obtained. Electronic devices. [Mathematical Formula 1] (1) (2) Here, is the first attenuation correction information, is the second attenuation correction information, is the damping coefficient for the fundamental harmonic frequency, is the damping coefficient for the second harmonic frequency, n is the number of reflections of the reflected wave, and L represents the thickness of the material.

3. In paragraph 2, The above processor, According to the following [Mathematical Formula 2], the basic harmonic information is calculated using the first attenuation correction information, and According to the following [Mathematical Formula 3], the second harmonic information is set to be calculated using the second attenuation correction information. Electronic devices. [Equation 2] [Equation 3] Here, (L) is the basic harmonic information, (L) is the second harmonic information, is the initial amplitude, k is the fundamental wavenumber, is the fundamental angular frequency, represents the acoustic nonlinear coefficient of the above material.

4. In paragraph 2, The above processor, Using the above first attenuation correction information, according to the following [Mathematical Formula 4], the first amplitude correction information and the first phase correction information for the superposition of the basic harmonic waves are calculated, and Using the above second attenuation correction information, according to the following [Mathematical Formula 5], the second amplitude correction information and the second phase correction information for the superposition of the second harmonic wave are set to be calculated. Electronic devices. [Equation 4] (1) (2) [Equation 5] (1) (2) Here, is the first amplitude correction information, is the second amplitude correction information, is the first phase correction information, represents the second phase correction information.

5. In paragraph 4, According to the following [Mathematical Formula 6], the basic harmonic information is calculated using the first amplitude correction information and the first phase correction information, According to the following [Mathematical Formula 7], the second harmonic information is set to be calculated using the second amplitude correction information and the second phase correction information. Electronic devices. [Equation 6] [Equation 7] 6. In paragraph 5, The above processor, According to the following [Mathematical Formula 8], the acoustic nonlinear coefficient is determined using the first amplitude correction information, the second amplitude correction information, the fundamental harmonic information, and the second harmonic information. Electronic devices. [Equation 8] 7. In a method of operating an electronic device for determining the acoustic nonlinear coefficient of a material, A step of obtaining first attenuation correction information for attenuation correction of the fundamental harmonic of the reflected wave signal and second attenuation correction information for attenuation correction of the second harmonic of the reflected wave signal by using the travel distance of the reflected wave signal within the material based on the number of reflections of the reflected wave signal at the boundary of the material; Including, Using the first attenuation correction information and the second attenuation correction information, the acoustic nonlinear coefficient of the material ( ) step of determining; including, How an electronic device operates.

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