A method for activating a gas, wherein an electrically conductive aeromaterial having a pore space comprising the gas is electrically contacted and at least one electric current, which varies over time, flows through the aeromaterial, wherein the aeromaterial exhales gas from the pore space when the electrical power consumption is increased and inhales gas from the surroundings of the aeromaterial when the power consumption is decreased, and wherein a temporally pulsed current having predefined pulse power levels, pulse durations and pulse spacings is fed through the aeromaterial and the temperature of the aeromaterial is changed by the time-varying current by 100 C. or more within one second or less. The invention also relates to an electrothermal gas actuator and to uses of a gas actuator.

A hearing device, particularly a hearing aid, has a housing, a signal processing unit arranged in the housing, a first sound generator disposed in the housing, and a second sound generator. The first sound generator and the second sound generator are configured to convert an output signal from the signal processing unit into sound. The second sound generator is a thermo-acoustic transducer.

Disclosed are a method, system and controller for simultaneously verifying amplitude and temperature parameters of an electrical-acoustic conversion device, including: inputting a sweep signal to the electrical-acoustic conversion device; testing the amplitude of the electrical-acoustic conversion device while adjusting the gain of the whole frequency band of the sweep signal until the maximum value of the tested amplitude is a maximum amplitude parameter Xmax, and testing the temperature of a voice coil at this moment; and if the tested temperature of the voice coil at this moment is higher or lower than Tmax, gradually reducing/increasing the gain of the sweep signal in the frequency band above a gain improvement frequency point until the tested temperature of the voice coil is Tmax, and then maintaining the gain of the sweep signal for a predetermined period of time and then testing the performance of the electrical-acoustic conversion device.

A hearing device, particularly a hearing aid, has a housing, a signal processing unit arranged in the housing, a first sound generator disposed in the housing, and a second sound generator. The first sound generator and the second sound generator are configured to convert an output signal from the signal processing unit into sound. The second sound generator is a thermo-acoustic transducer.

An acoustic liner may include a core with a plurality of resonator chambers, a perforated top sheet coupled to the core, and a backskin coupled to the core. A thermoacoustic speaker including nanomaterials may be coupled to at least one of the core, the backskin, and the perforated top sheet. A voltage may be applied to the thermoacoustic speaker. The thermoacoustic carbon nanotube speaker may create a dynamic excitation within a resonator chamber in the core. The dynamic excitation may change the liner acoustic impedance to achieve optimum noise attenuation over a wide range of frequencies or engine operating conditions.

A thermoacoustic device includes a substrate, a first electrode and a second electrode, at least two supporting members, and a first carbon nanotube film. The substrate includes a surface. The first electrode and the second electrode are located on the surface of the substrate and spaced from each other. The at least two supporting members are spaced from each other and respectively located on surfaces of the first electrode and the second electrode. The at least two supporting members include a plurality of carbon nanotubes parallel with each other and substantially perpendicular to the surface of the substrate. The first carbon nanotube film is supported by the at least two supporting members and has a portion between the at least two supporting members suspended above the substrate. The supporting members electrically connect the first carbon nanotube film with the first electrode and the second electrode.

A thermoacoustic device includes a base, a first electrode and a second electrode, at least two supporting members, and a first carbon nanotube film. The base includes a surface. The first electrode and the second electrode are located on the surface of the base and spaced from each other. The at least two supporting members are spaced from each other and respectively located on surfaces of the first electrode and the second electrode. The at least two supporting members include a plurality of carbon nanotubes parallel with each other and substantially perpendicular to the surface of the base. The first carbon nanotube film is supported by the at least two supporting members and has a portion between the at least two supporting members suspended above the base. The supporting members electrically connect the first carbon nanotube film with the first electrode and the second electrode.

A method for making thermoacoustic device includes following steps. A substrate having a first surface and second surface is provided. The first surface defines a plurality of grids. Grooves are formed on each of the plurality of grids. A first electrode and a second electrode are formed on each grid. The first electrode is spaced from the second electrode. One of the grooves is located between the first electrode and the second electrode. A number of carbon nanotube wires are applied on the first surface and electrically connected to the first electrode and the second electrode. A thermoacoustic device array is formed on the substrate by separating the carbon nanotube wires. A number of thermoacoustic device is formed by cutting the substrate according to the grids.

A handphone is configured to receive a first audio signal of a telecommunication conversation from a telecommunication device and send a second audio signal of the telecommunication conversation to the telecommunication device. A modulated ultrasound frequency audio signal that is directional is created from the first audio signal of the telecommunication conversation. The modulated ultrasound frequency audio signal is output via a loudspeaker. A direction of the modulated ultrasound frequency audio signal is controlled by a physical object and a location of the loudspeaker.

A method for making a thermoacoustic device array includes the following step. A substrate having a surface is provided. The surface defines a grid having a number of cells. A number of recesses are defined on each of the cells. The recesses are parallel with and spaced from each other. A first electrode and a second electrode are formed on each of the cells. The first electrode is spaced from the second electrode, and one of the recesses is located between the first electrode and the second electrode. A sound wave generator is applied on the substrate and electrically connected to the first electrode and the second electrode. The sound wave generator is suspended over the recesses. The sound wave generator is separated according to the cells.