An electro-acoustic transducer includes a base and a plurality of vibration portions. Each of the vibration portions includes a piezoelectric transduction layer and has two connection ends and a free end. The connection portions are connected to the base, and the free ends are separated from one another. The piezoelectric transduction layers are adapted to receive electrical signals to deform, such that the vibration portions are driven to vibrate and generate corresponding acoustic waves. The vibration portions are adapted to receive acoustic waves to vibrate, such that the piezoelectric transduction layers are driven to deform and generate corresponding electrical signals.

A display apparatus includes a display, a loudspeaker and a controller. The controller is configured to: perform, based on one or both of (i) image information of an image that is displayed on the display, and (ii) sound information of sound that is output from the loudspeaker, electric current control processing that controls a sum of an electric current to be supplied to the display and an electric current to be supplied to the loudspeaker.

A display apparatus includes a display, a loudspeaker and a controller. The controller is configured to: perform, based on one or both of (i) image information of an image that is displayed on the display, and (ii) sound information of sound that is output from the loudspeaker, electric current control processing that controls a sum of an electric current to be supplied to the display and an electric current to be supplied to the loudspeaker.

An optical microphone assembly comprises a rigid substrate; an interferometric arrangement, a light source, at least one photo detector and an enclosure. The interferometric arrangement comprises a membrane and at least one optical element spaced from the membrane, wherein the at least one optical element comprises a surface of the substrate and/or is disposed on a surface of the substrate. The light source is arranged to provide light to the interferometric arrangement such that a first portion of the light propagates along a first optical path via the interferometric arrangement and a second portion of the light propagates along a second different optical path via the interferometric arrangement, thereby giving rise to an optical path difference between the first and second optical paths which depends on a distance between the membrane and the optical element. The photo detector(s) are arranged to detect at least part of an interference pattern generated by said first and second portions of light dependent on said optical path difference. The enclosure is arranged to form an acoustic cavity in fluid communication with one side of the membrane. The volume of the acoustic cavity is at least 3 mm multiplied by d.sup.2, where d is a diameter of the membrane.

A system for enhancing the separation of particles or fluids from water is disclosed. A settling tank or skim tank is provided with an open submersible acoustophoretic separator. In a skim tank, the separator captures and holds oil droplets or particles, permitting them to coalesce until they are large enough and have sufficient buoyant force to float to the top of the tank. In a settling or sediment tank, separator captures and holds particles until they are large enough that the force of gravity causes them to settle out of the water. The acoustophoretic device thus speeds up separation of the particles or droplets from the water.

A system for enhancing the separation of particles or fluids from water is disclosed. A settling tank or skim tank is provided with an open submersible acoustophoretic separator. In a skim tank, the separator captures and holds oil droplets or particles, permitting them to coalesce until they are large enough and have sufficient buoyant force to float to the top of the tank. In a settling or sediment tank, separator captures and holds particles until they are large enough that the force of gravity causes them to settle out of the water. The acoustophoretic device thus speeds up separation of the particles or droplets from the water.

In accordance with an embodiment, a method includes determining an amplitude of an input signal provided by a capacitive signal source, compressing the input signal in an analog domain to form a compressed analog signal based on the determined amplitude, converting the compressed analog signal to a compressed digital signal, and decompressing the digital signal in a digital domain to form a decompressed digital signal. In an embodiment, compressing the analog signal includes adjusting a first gain of an amplifier coupled to the capacitive signal source, and decompressing the digital signal comprises adjusting a second gain of a digital processing block.

In accordance with an embodiment, a method includes determining an amplitude of an input signal provided by a capacitive signal source, compressing the input signal in an analog domain to form a compressed analog signal based on the determined amplitude, converting the compressed analog signal to a compressed digital signal, and decompressing the digital signal in a digital domain to form a decompressed digital signal. In an embodiment, compressing the analog signal includes adjusting a first gain of an amplifier coupled to the capacitive signal source, and decompressing the digital signal comprises adjusting a second gain of a digital processing block.

A method for making thermoacoustic device includes following steps. A silicon substrate having a first surface and second surface opposite to the first surface is provided. The first surface is patterned by forming a plurality of grooves substantially oriented along a first direction, wherein the plurality of grooves is spaced from each other, and a bulge is formed between each two adjacent grooves. An insulating layer is coated on the patterned surface. A first electrode and a second electrode are formed on the insulating layer, wherein the first electrode and the second electrode are spaced from each other. A carbon nanotube structure is applied on the insulating layer, wherein the carbon nanotube structure is electrically connected to the first electrode and the second electrode, the carbon nanotube structure is suspended above the plurality of grooves.

Apparatus is provided featuring an acoustic driver and a transducer. The acoustic driver is configured to provide an acoustic driver signal having a frequency that can be adjusted to yield a given wavelength, which in turn, will selectively capture a particular particle size of particles in a fluid, mixture or process flow. The transducer is configured to respond to the acoustic driver signal and provide an acoustic signal having a standing wave at the frequency in order to yield the given wavelength that will selectively capture the particular particle size of the particles in the fluid, mixture or process flow, in order to determine the mass of the particles having the particular particle size in the fluid, mixture or process flow.