215 results about "Interdigitated electrode" patented technology

The invention discloses a taste receptor derived peptide capable of effectively detecting caffeine and a biosensor, and belongs to the technical field of biosensors. Currently, traditional spectrum and chromatography on which caffeine detection depends have the problems of expensive instruments, time-consuming detection, complex procedures and the like, and a sensor based on a taste receptor is also faced with the limitations of high cost, complex preparation process and easy inactivation of the receptor. In order to solve the problem, the taste receptor derived peptide provided by the invention has an amino acid sequence as shown in SEQ ID NO: 4, the biosensor comprises a substrate and a disc interdigital electrode, and a carbon nanotube is firmly attached to the electrode and is connected with the taste receptor derived peptide. The biosensor can specifically detect caffeine in a beverage, has no response to other substances, and has application potential in the fields of food quality control, clinical drug monitoring, public health safety assessment and the like.

The invention relates to a rigid-flexible combined self-sensing suction cup and a control method and system thereof, and belongs to the field of robot grabbing. The suction cup comprises a suction cup shell, a self-sensing unit, a bionic microstructure contact unit and a suction cup nozzle, the self-sensing unit and the bionic microstructure contact unit are sequentially arranged on the suction cup shell in an annular structure, the suction cup nozzle is arranged in the middle of the suction cup shell, and the self-sensing unit comprises a flexible substrate layer, an interdigital electrode layer and a sensing unit array layer. The flexible substrate layer is attached to the suction cup shell, and the interdigital electrode layer is wrapped in the middle by the flexible substrate layer and the sensing unit array layer. According to the control system and the control method, the adsorption force is fitted by collecting data of the sensor on the suction cup, whether the adsorption force meets the grabbing requirement or not is judged, and if not, the air pump is dynamically regulated and controlled, and the grabbing adsorption force is adjusted. Static pressure and dynamic pressure in the grabbing process can be effectively sensed, and high adaptability and stability of the suction cup in executing the grabbing task are guaranteed.

The invention discloses a pressure detection system, and relates to the technical field of intelligent wearing, and the pressure detection system comprises 1) a flexible substrate layer which is used for fitting skin and sensing external tiny pressure changes; the micro-column array layer is composed of a plurality of micro-column structures and used for amplifying and conducting the pressure change sensed by the flexible substrate layer; the flexible gel sensing layer is used for receiving the pressure transmitted by the micro-column array layer and generating an electric signal; 4) a packaging layer; an interdigital electrode layer is arranged in the flexible gel sensing layer, an electric signal of the flexible gel sensing layer changes along with the change of external pressure, and the detection of a pressure electric signal is realized through the interdigital electrode layer. By means of the design, high-sensitivity response to tiny pressure changes can be achieved, micro-pressure signals are remarkably amplified, meanwhile, the problem of hysteresis effect generally existing in traditional silica gel or metal film materials is solved, and therefore the response speed of the sensor is greatly increased.

An integrated pressure and temperature hydrogel array sensor, which comprises: a plurality of sensing array units arranged in an array. Each sensing array unit comprises interdigitated electrodes (101) and a hydrogel layer (102) covering the surface of the interdigitated electrodes (101), wherein the hydrogel layer (102) is fixed to the interdigitated electrodes (101) by means of photocuring, and the hydrogel layer (102) is in intimate contact with the surface of the interdigitated electrodes (101); the interdigitated electrodes (101) are two coplanar nested interdigitated electrodes prepared on a flexible circuit board; the hydrogel layer (102) is a hydrogel layer having variations in crosslink density and height; and the hydrogel layer (102) comprises a high-crosslink-density hydrogel region (102a) and a low-crosslink-density hydrogel region (102b). A flexible sensing structure based on photocurable hydrogel that features an arrayed electrode design can simultaneously monitor variations in a pressure signal and a temperature signal by means of an array module acquisition system. Further disclosed is a preparation method for an integrated pressure and temperature hydrogel array sensor.

The present invention generally relates to a lanthanum oxide (La2O3)-reduced graphene oxide (rGO) nanocomposite-based humidity sensor device designed for high-performance detection across a wide relative humidity range of 11-95%. The sensor comprises an interdigitated electrode (IDE) substrate featuring a plurality of electrodes patterned on an insulating base. A sensing layer composed of a nanocomposite of La2O3 and rGO in the ratio of (x)La2O3+(1−x)rGO, where x ranges from 0.1 to 0.3, is deposited on the IDE using a drop-casting method. The slurry used for deposition includes ethanol as a solvent, and the coated substrate is subjected to mild heating at 60° C. to 80° C. for 1 to 2 hours to enhance adhesion and uniformity. The IDEs, made of gold, silver, or their composition, are connected to external leads interfaced with a measurement unit that enables real-time monitoring and quantification of humidity changes in the surrounding environment.

An acoustic wave device includes a piezoelectric film including a piezoelectric layer made of lithium niobate, a first interdigitated electrode including a first busbar and first electrode fingers, a second interdigitated electrode including a second busbar and second electrode fingers and interdigitated with the first electrode fingers, and a third electrode including third electrode fingers side by side with the first and second electrode fingers, connected to a potential different from potentials of the first and second interdigitated electrodes and a connection electrode connecting adjacent third electrode fingers to each other. The connection electrode connects ends of adjacent third electrode fingers closer to at least the first busbar. The connection electrode is between at least the first busbar and ends of the second electrode fingers. Mass-addition films are provided in at least a portion of at least one of first, second, and third gap regions.

The invention relates to the technical field of ultraviolet photoelectric detectors, in particular to an MSM structure ultraviolet photoelectric detector based on p-Si / Ga2O3 / ZnO and a preparation method of the MSM structure ultraviolet photoelectric detector. Comprising a p-Si substrate; the Ga2O3 thin film layer is arranged on the p-Si substrate; the ZnO thin film layer is arranged on the Ga2O3 thin film layer; and the interdigital electrode is arranged on the ZnO thin film layer. The interdigital electrode is a Ti interdigital electrode, the width of the interdigital electrode is 50-100 m, the length of the interdigital electrode is 600-1000 m, and the electrode interval is 50-100 m; and the p-Si substrate is a double-surface polished boron-doped p-Si substrate. In the preparation process, magnetron sputtering and thermal evaporation deposition are adopted to prepare the photoelectric detector. The method has the advantages that manufacturing cost is reduced; the suppression ratio of UV / Vis-NIR light is improved, so that the device has higher spectral selectivity; the detection wavelength range is widened, and sensitive detection of UVA-UVC is realized.

A sensing element for detecting a target gas or gases is disclosed. The element includes a pair of interdigitated electrodes, with a gap between each electrode in the pair. A high surface area metal oxide nanomaterial decorated with a noble metal is deposited on interdigitated electrode pair to bridge the gap. The surface area of the metal oxide nanomaterial is greater than 100m2 / g and the size of the metal oxide nanomaterial is within the range of 100-200nm. The resistance across the pair of electrodes varies when the metal oxide nanomaterial binds with the target gas or gasses. From this sensing element, sensor chips and sensor modules may be constructed to detect multiple gases.

The invention relates to the field of intelligent detection of power transmission and transformation equipment, in particular to an ultrasonic sensor for the power transmission and transformation equipment. The ultrasonic sensor comprises a substrate, a bottom electrode layer, a top electrode layer and a three-dimensional piezoelectric film, the three-dimensional piezoelectric film is located between the bottom electrode layer and the top electrode layer, the three-dimensional piezoelectric film is integrally arranged on the substrate, and the three-dimensional piezoelectric film is insulated from the bottom electrode layer and the top electrode layer; the bottom electrode layer and the top electrode layer are composed of interdigital electrode arrays. The three-dimensional piezoelectric film is formed by compositing nanowires and a polyvinylidene fluoride heterostructure through an electrostatic spinning process. The nanowire is a rare earth element doped ZnO nanowire synthesized by a hydrothermal method. According to the invention, the material sensitivity is improved, the stability of the ultrasonic sensor in a high-temperature / high-humidity environment is enhanced, and high-precision detection of high-frequency ultrasonic waves generated by partial discharge of power transmission and transformation equipment is realized.

The invention provides a capacitive sweat detection sensor and a preparation method thereof. The method comprises the following steps: respectively preparing a hydrophobic film layer, a micro-channel layer and an electrode layer; sequentially pasting and assembling the hydrophobic film layer, the micro-channel layer and the electrode layer from top to bottom to form the capacitive sweat detection sensor, wherein the hydrophobic thin film layer comprises a super-hydrophobic nanowire thin film, an MA layer and a super-hydrophilic nanowire thin film formed on one side, far away from the super-hydrophobic nanowire thin film, of the MA layer; the electrode layer comprises an electrode substrate, an interdigital electrode and a separation layer which are arranged in sequence. The interference of external stress and ions in sweat on the detection result can be reduced, the detection precision of the sensor is improved, and the application scene is expanded.

The invention discloses a calculation spectrometer based on a random multimode waveguide grating and a spectrum reconstruction method. Comprising a silicon substrate layer, a silicon dioxide buried oxide layer, a lithium niobate waveguide layer, a silicon dioxide coating layer and an interdigital electrode which are sequentially stacked from bottom to top, a mode multiplexer, a multi-mode waveguide spiral line and multi-mode waveguide gratings are formed on the lithium niobate waveguide layer, the mode multiplexer is communicated with the multi-mode waveguide spiral line, the multi-mode waveguide spiral line at least comprises a section of multi-mode straight waveguide, a plurality of non-periodically distributed multi-mode waveguide gratings are arranged on the multi-mode straight waveguide, and the multi-mode waveguide gratings are arranged on the multi-mode straight waveguide. And each multimode waveguide grating unit adopts a Bragg grating structure and comprises two groups of grating tooth structures which are respectively positioned on two sides of the multimode straight waveguide. According to the invention, the electrical control logic can be simplified, the disordered resonance of different modes in the spiral line can provide high spectral reconstruction resolution, and meanwhile, the lithium niobate electro-optical modulation can realize rapid and low-power consumption measurement channel scanning.

The invention relates to the technical field of gas sensing, in particular to a chemical resistance type gas sensor based on an organic semiconductor polymer film and a preparation method and application thereof, and the chemical resistance type gas sensor comprises a substrate, and a conversion element and a sensing element which are integrated on the substrate; the sensing element is an organic semiconductor polymer P3HT film; a P3HT solution is spin-coated on a substrate integrated with an interdigital electrode to form a P3HT thin film, then vacuum oxygen plasma treatment is performed by adopting a Hall ion source to modify the P3HT thin film, so that the chemical resistance type gas sensor for ammonia gas sensing is successfully constructed, the surface of the P3HT thin film subjected to oxygen plasma treatment has an oxygen-containing functional group, and the surface of the P3HT thin film subjected to oxygen plasma treatment has an oxygen-containing functional group. The P3HT thin film has excellent conductivity, when ammonia gas contacts with the surface of the P3HT thin film, the resistance change of the P3HT thin film can be detected by an instrument, then the sensitivity of the sensor is obtained, and compared with the prior art, the gas sensor is high in ammonia gas responsivity and has high-selectivity low detection limit.

A three-dimensional (3D) microelectrode array device for in vitro electrophysiological applications includes a substrate and micro vias extending from the bottom face to the top face of the substrate. A microneedle at each micro via extends from the bottom face upward beyond the top face and forms a hypodermic microneedle array on the top face. Metallic traces on the bottom face interconnect the hypodermic microneedles to form the 3D microelectrode array. A microheater is positioned on the bottom face of the substrate. Microfluidic ports may be formed at the substrate. Interdigitated electrodes may be formed at the substrate.

This invention provides a surface acoustic wave (SAW) filter, comprising a piezoelectric layer and interdigitated electrodes. The interdigitated electrodes are disposed on the piezoelectric layer and include at least a first metal layer and a second metal layer stacked together. The first metal layer is made of platinum or an alloy with platinum as the main component, and the second metal layer is made of aluminum or an alloy with aluminum as the main component. By setting the material of the second metal layer to aluminum or an alloy with aluminum as the main component, the uniformity of metal coverage of the electrode structure can be effectively improved, avoiding excessive local resistance or structural defects caused by poor coverage. Setting the material of the first metal layer to platinum or an alloy with platinum as the main component provides reliable support for the second metal layer, reducing the risk of deformation or corrosion of the aluminum layer in subsequent processes. By using a stacked structure of two complementary materials for the interdigitated electrodes, both structural miniaturization and improved overall electrical performance and structural reliability of the interdigitated electrodes are achieved.

The invention discloses a triboelectricity-variable reluctance hybrid power generation device and system of a bearing structure, the triboelectricity-variable reluctance hybrid power generation device of the bearing structure comprises a support frame, a rotating shaft, a rolling shaft, a friction power generation assembly and a variable reluctance power generation assembly, the friction power generation assembly comprises a dielectric ring and an interdigital electrode plate, the dielectric ring is annularly arranged on a retainer of the rotating shaft, the interdigital electrode plate surrounds the periphery of the rotating shaft and is connected with the supporting frame, the dielectric ring and the interdigital electrode plate are adjacent and opposite, the variable reluctance power generation assembly comprises a magnet coil and a gear-shaped nut, the gear-shaped nut is arranged on the rotating shaft in a sleeving mode, and convex teeth are arranged on the peripheral surface of the gear-shaped nut; the multiple magnet coils are arranged in the circumferential direction of the supporting frame at intervals, and the multiple magnet coils surround the periphery of the gear-shaped nut. According to the friction electricity-variable reluctance hybrid power generation device of the bearing structure, in-situ self-sensing of the running state of the bearing can be achieved, the structure is compact, and external power supply equipment and related wiring do not need to be arranged.

This invention discloses an MSM interdigitated wideband ultraviolet photodetector and its fabrication method, belonging to the field of semiconductor technology. The detector includes: a substrate; an AlN nucleation layer on the substrate surface; a heterostructure on the surface of the AlN nucleation layer away from the substrate, wherein the heterostructure includes GaN, GaON, and Ga2O3 layers stacked sequentially from bottom to top; and interdigitated electrodes on the surface of the Ga2O3 layer away from the substrate. This invention introduces a GaON layer between the Ga2O3 and GaN heterojunctions. This GaON layer acts as a lattice buffer layer, effectively releasing the lattice mismatch stress between Ga2O3 and GaN, significantly improving the interface quality of the heterojunction, and enhancing the separation and collection efficiency of charge carriers, thus significantly improving the overall performance of the MSM interdigitated ultraviolet photodetector.

The present invention provides a double silicon-gold bonded MEMS deformable mirror and its fabrication method. The MEMS deformable mirror comprises a silicon wafer substrate, a silicon nitride insulating layer, a lower polysilicon electrode, a first phosphosilicate glass sacrificial layer, an upper interdigitated electrode, a first bonding electrode layer, an SOI wafer structure, a second bonding electrode layer, and a gold-based reflective mirror surface. The fabrication method sequentially involves silicon wafer substrate pretreatment, silicon nitride insulating layer deposition, lower polysilicon electrode formation, first phosphosilicate glass sacrificial layer deposition and thinning, upper interdigitated electrode and related structure etching, first bonding electrode layer formation, SOI wafer pretreatment and solution channel formation, second phosphosilicate glass sacrificial layer filling, second bonding electrode layer formation, gold-to-gold hot-compression bonding, deep silicon etching, structural release and annealing, and gold-based reflective mirror surface fabrication and packaging. This invention can simplify the process flow, improve the correction performance of optical systems, and has broad market application prospects.

A surface acoustic wave (SAW) device includes: a piezoelectric layer; an interdigitated electrode structure located on the piezoelectric layer; a wiring layer located on the piezoelectric layer and electrically connected to the interdigitated electrode structure; an interconnect layer located on the wiring layer; bumps located on the interconnect layer; and a metallization structure located between the interconnect layer and the bumps, electrically connecting the interconnect layer and the bumps and preventing material from the bumps from penetrating into the interconnect layer. The metallization structure on the interconnect layer prevents the bumps from directly contacting the interconnect layer, instead connecting them electrically through the metallization structure. This prevents the material of the bumps from fusing with the material of the interconnect layer and intruding into the device, thus preventing semiconductor device failure and improving the performance of the semiconductor device. Furthermore, the metallization structure's location between the bumps and the interconnect layer enhances the adhesion between the bumps and the interconnect layer.

This invention discloses a pressure sensor based on gradient resistance, possessing both wide measurement range and high sensitivity. From bottom to top, it comprises: a lower encapsulation layer; interdigitated electrodes attached to the upper surface of the lower encapsulation layer; a high-resistance sensing layer, which is a flat layer without any microstructures; a low-resistance sensing layer, the surface of which has a 5×5~6×6 hemispherical microstructure, the hemispherical microstructure surface being connected to the high-resistance sensing layer; and an upper encapsulation layer, which is disposed opposite to the lower encapsulation layer. This invention also discloses a method for fabricating a pressure sensor based on gradient resistance, possessing both wide measurement range and high sensitivity. This method constructs a two-layer structure consisting of a high-resistance flat sensing layer and a low-resistance hemispherical microstructure sensing layer, utilizing the current transfer mechanism caused by the dynamic change in the interlayer contact area of ​​the two sensing layers under pressure.

The present invention proposes a surface acoustic wave microfluidic acoustic tweezers device with adjustable multiple degrees of freedom, which belongs to the field of microfluidic technology. It can realize the dynamic adjustable function of multiple key parameters such as the acoustic wave propagation speed, angle and structure of the microfluidic device. It mainly includes a surface acoustic wave generation module, a surface acoustic wave action module, and a multi-dimensional adjustment module. The surface acoustic wave generation module mainly includes a piezoelectric material substrate and a flexible interdigitated electrode. The surface acoustic wave action module is composed of a PDMS microchannel or a PDMS microring, which is mainly determined by the function of the acoustic tweezers device. The multi-dimensional adjustment module can freely adjust the relative position of the flexible interdigitated electrode, as well as its position and angle relative to the piezoelectric material substrate, thereby controlling the propagation speed and action effect of the acoustic wave. The present invention can achieve different microfluidic application requirements through multi-dimensional adjustment of the flexible interdigitated electrode and the piezoelectric material substrate.

The present invention discloses a Cu-BTC single crystal resistive humidity sensor and a preparation method, belonging to the field of MOFs material sensing. The Cu-BTC single crystal resistive humidity sensor of the present invention comprises a planar interdigitated electrode produced by ultrafast laser-induced processing of the Cu-BTC single crystal surface and unprocessed Cu-BTC single crystal material between the interdigitated fingers. The planar electrode is prepared by the following steps: S1: preparing a Cu-BTC single crystal sample with a length and width of the to-be-processed surface greater than or equal to 100 μm; S2: using an ultrafast laser processing device to perform ultrafast laser-induced processing on the Cu-BTC single crystal sample in step S1 under set laser processing parameters to obtain the planar interdigitated electrode; wherein the ultrafast laser wavelength is 1030 nm, the pulse width t is 1.2 ps≤t≤10 ps, ​​the processing power P is 3 mW≤P≤8 mW, the scanning speed v is 200 μm / s≤v≤360 μm / s, the processing interval is 1 μm, and the focused spot is 4 μm. The Cu-BTC single crystal resistive humidity sensor can detect humidity in the range of 5% to 90% RH, with a response time of up to 2 s and good selectivity, stability, and cyclability.

A surface acoustic wave resonator (100) comprises a layered substrate including a carrier substrate (110) and a dielectric layer (112) having a low acoustic velocity. Another dielectric layer (122) is disposed on a piezoelectric layer (113) and interdigitated electrodes (131, 132) having an acoustic velocity lower than the acoustic velocity of the carrier substrate (110) and a positive temperature coefficient of frequency.

The invention discloses a flexible all-inorganic piezoelectric vibration sensor and a preparation method thereof. The piezoelectric sensor is characterized in that the used flexible substrate is a fluorine crystal mica substrate, the used functional material is an inorganic piezoelectric film, and the electrode structure is an interdigital electrode. The sensor has bendable flexibility and excellent vibration response, and can be applied to a wearable health monitoring system.

The invention provides a filter forming method, which comprises the following steps of: providing a substrate; continuously depositing an electrode metal layer and a multifunctional metal layer on the substrate; etching the multifunctional metal layer to form an initial mass block; and etching the initial mass block, the electrode metal layer and the multifunctional metal layer at the same time to obtain a plurality of interdigital electrodes which are arranged in a crossed manner and mass blocks arranged on the interdigital electrodes. According to the embodiment of the invention, the interdigital electrode and the mass block can be manufactured at the same time only through one-time continuous metal deposition and two-time etching, and the production process is simplified; meanwhile, in combination with the application of a self-alignment process, the lamination precision requirement between the mass block and the interdigital electrode is effectively ensured.

The invention provides a dielectric capacitor, a preparation process thereof and power electronic equipment. The dielectric capacitor comprises a substrate, an Aurivillius compound film and a gear shaping electrode which are sequentially stacked, the gear shaping electrode comprises two tooth electrodes which are crossed with each other, and each tooth electrode comprises a gear shaping part and a pin; the gear shaping part comprises a gear shaping connecting side edge and at least two gear shaping connected with one side of the gear shaping connecting side edge, and the pin is connected with at least one end of the gear shaping connecting side edge; the insertion teeth of the two tooth electrodes are arranged in a staggered manner; along the direction parallel to the Aurivillius compound film and perpendicular to the insertion teeth, the width D of the insertion teeth of the two tooth electrodes and the distance L between the insertion teeth of the two tooth electrodes and the adjacent insertion teeth meet the equation that D: L = (0.2-2): 1. According to the dielectric capacitor, the anti-fatigue performance, the environmental protection performance, the dielectric constant and the energy density of the dielectric capacitor are improved at the same time.

This invention discloses a method and system for detecting the strongest Rayleigh acoustic current in immobilized microdroplets. Specifically, it involves: calculating the acoustic current suppression coefficient through experimental quantitative testing to establish a quantitative mapping relationship between acoustic current intensity and droplet contact angle; utilizing an electrowetting structure composed of interdigitated electrodes, a dielectric layer, and a hydrophobic layer to actively regulate the droplet contact angle through an applied voltage; and dynamically adjusting the applied voltage in real time by monitoring the droplet vibration amplitude, particle velocity, and contact angle through a collaborative control program to maintain the acoustic current intensity at its strongest. This invention also provides a detection system for implementing the above method, including an indium tin oxide transparent interdigitated electrode substrate, a lead zirconate titanate piezoelectric transducer, a laser Doppler vibrometer, a microscope, and a collaborative control module. This invention can maximize and dynamically maintain the Rayleigh acoustic current intensity in immobilized microdroplets, significantly accelerating the solid-liquid interface mass transfer process, and is applicable to biochemical analysis fields such as rapid immunoassay and biological particle mixing.

This application discloses a surface acoustic wave (SAW) resonator, filter, and electronic device, relating to the field of resonators. The SAW resonator includes: a piezoelectric substrate; interdigitated electrodes located on one side surface of the piezoelectric substrate; the interdigitated electrodes include first and second fingers alternately arranged along a first direction, the first and second fingers extending along a second direction, the first and second directions intersecting in a plane parallel to the piezoelectric substrate; a first groove is formed in the surface of the piezoelectric substrate between adjacent first and second fingers; two reflective gratings are disposed on the same side surface of the piezoelectric substrate as the interdigitated electrodes; in the first direction, the interdigitated electrodes are located between the two reflective gratings; the reflective gratings include multiple third fingers arranged sequentially along the first direction; a second groove is formed in the surface of the piezoelectric substrate between adjacent third fingers. The technical solution of this application can improve the steepness of the filter in the transition band.

The application provides a kind of based on interdigital electrode redox ion detection method and sensor, above-mentioned method includes: control power supply is applied on interdigital electrode first voltage value of first time period of preset positive voltage, make redox ion in liquid to be detected near first electrode enrichment;Wherein, in first electrode applies positive voltage, and in second electrode applies negative voltage, forms positive voltage;Control power supply is applied on interdigital electrode second voltage value of second time period of preset reverse voltage, makes redox ion after being reduced after enrichment in first electrode near and generates output current;According to the output current, determine the concentration of redox ion in liquid to be detected.The technology improves the concentration of redox ion during detection by the method of first enrichment and then detection of redox ion, improves detection precision.

Provided are a two-way fluid sensing device, a two-way fluid sensing method, and the manufacturing method of the fluid sensing device. The fluid sensing device includes: a substrate, which is a through-hole membrane with channels penetrating from the top surface to the bottom surface of the substrate; an interdigitated electrode having a plurality of interdigitated structures and disposed on the substrate; and a fluid sensing layer containing fluid sensing material and disposed on the interdigitated electrode. Therefore, fluid molecules can interact with the fluid sensing layer from both the top and bottom sides of the fluid sensing device, such that the fluid sensing device of the present invention can exhibit higher sensitivity, and can be vertically integrated with other electronic devices or 3D circuits.

The present disclosure relates to a method for processing capacitance values generated by capacitive sensors with interdigitated electrodes supported by a seat of a vehicle.