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Piezoelectric Ceramics
Piezoelectricity (, ) is the electric charge that accumulates in certain solid materials—such as crystals, certain ceramics, and biological matter such as bone, DNA, and various proteins—in response to applied mechanical stress. The word ''piezoelectricity'' means electricity resulting from pressure and latent heat. It is derived from the Greek word ; ''piezein'', which means to squeeze or press, and ''ēlektron'', which means amber, an ancient source of electric charge. The piezoelectric effect results from the linear electromechanical interaction between the mechanical and electrical states in crystalline materials with no inversion symmetry. The piezoelectric effect is a reversible process: materials exhibiting the piezoelectric effect also exhibit the reverse piezoelectric effect, the internal generation of a mechanical strain resulting from an applied electrical field. For example, lead zirconate titanate crystals will generate measurable piezoelectricity when their ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Piezoelectric Balance Presented By Pierre Curie To Lord Kelvin, Hunterian Museum, Glasgow
Piezoelectricity (, ) is the electric charge that accumulates in certain solid materials—such as crystals, certain ceramics, and biological matter such as bone, DNA, and various proteins—in response to applied mechanical stress. The word ''piezoelectricity'' means electricity resulting from pressure and latent heat. It is derived from the Greek word ; ''piezein'', which means to squeeze or press, and ''ēlektron'', which means amber, an ancient source of electric charge. The piezoelectric effect results from the linear electromechanical interaction between the mechanical and electrical states in crystalline materials with no inversion symmetry. The piezoelectric effect is a reversible process: materials exhibiting the piezoelectric effect also exhibit the reverse piezoelectric effect, the internal generation of a mechanical strain resulting from an applied electrical field. For example, lead zirconate titanate crystals will generate measurable piezoelectricity when their ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microbalance
A microbalance is an instrument capable of making precise measurements of weight of objects of relatively small mass: of the order of a million parts of a gram. In comparison, a standard analytical balance is 100 times less sensitive; i.e. it is limited in precision to 0.1 milligrams. Microbalances are generally used in a laboratory as standalone instruments but are also incorporated into other instruments, such as thermogravimetry, sorption/desorption systems, and surface property instruments. It is the precision of the microbalance that distinguishes it from other weighing devices. Types A quartz crystal microbalance (QCM) is a very sensitive mass deposition sensor based on the piezoelectric properties of the quartz crystal. This technique uses the changes in resonance frequency of the crystal to measure the mass on the surface because the resonance frequency is highly dependent on any changes of the crystal mass. A quartz crystal microbalance is capable of measuring mass de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
René Just Haüy
René Just Haüy () FRS MWS FRSE (28 February 1743 – 1 June 1822) was a French priest and mineralogist, commonly styled the Abbé Haüy after he was made an honorary canon of Notre Dame. Due to his innovative work on crystal structure and his four-volume ''Traité de Minéralogie'' (1801), he is often referred to as the "Father of Modern Crystallography". During the French revolution he also helped to establish the metric system. Biography Early life René-Just Haüy was born at Saint-Just-en-Chaussée on February 28, 1743, in the province of Île-de-France (later the ''département'' of Oise). His parents were Just Haüy, a poor linen-weaver, and his wife Magdeleine Candelot. Haüy's interest in the services and music of the local church brought him to the attention of the prior of a nearby abbey of Premonstrants. Through him, Haüy was introduced to a colleague in Paris and obtained a scholarship to the College of Navarre. Haüy eventually became an usher, and in 1764 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Franz Aepinus
Franz Ulrich Theodor Aepinus (13 December 172410 August 1802) was a German mathematician, scientist, and natural philosopher residing in the Russian Empire. Aepinus is best known for his researches, theoretical and experimental, in electricity and magnetism. Early life He was born at Rostock in the Duchy of Mecklenburg-Schwerin. He was descended from Johannes Aepinus (1499–1553), the first to adopt the Greek form (αἰπεινός) of the family name Hugk or Huck, and a leading theologian and controversialist at the time of the Protestant Reformation. Career After studying medicine for a time, Franz Aepinus devoted himself to the physical and mathematical sciences, in which he soon gained such distinction that he was admitted a member of the Prussian Academy of Sciences. In 1755, he was briefly the director of the Astronomisches Rechen-Institut. In 1757, he settled in St Petersburg as member of the Russian Academy of Sciences and professor of physics, and remained there til ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carl Linnaeus
Carl Linnaeus (; 23 May 1707 – 10 January 1778), also known after his ennoblement in 1761 as Carl von Linné Blunt (2004), p. 171. (), was a Swedish botanist, zoologist, taxonomist, and physician who formalised binomial nomenclature, the modern system of naming organisms. He is known as the "father of modern taxonomy". Many of his writings were in Latin; his name is rendered in Latin as and, after his 1761 ennoblement, as . Linnaeus was born in Råshult, the countryside of Småland, in southern Sweden. He received most of his higher education at Uppsala University and began giving lectures in botany there in 1730. He lived abroad between 1735 and 1738, where he studied and also published the first edition of his ' in the Netherlands. He then returned to Sweden where he became professor of medicine and botany at Uppsala. In the 1740s, he was sent on several journeys through Sweden to find and classify plants and animals. In the 1750s and 1760s, he continued to collect an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electric Potential
The electric potential (also called the ''electric field potential'', potential drop, the electrostatic potential) is defined as the amount of work energy needed to move a unit of electric charge from a reference point to the specific point in an electric field. More precisely, it is the energy per unit charge for a test charge that is so small that the disturbance of the field under consideration is negligible. Furthermore, the motion across the field is supposed to proceed with negligible acceleration, so as to avoid the test charge acquiring kinetic energy or producing radiation. By definition, the electric potential at the reference point is zero units. Typically, the reference point is earth or a point at infinity, although any point can be used. In classical electrostatics, the electrostatic field is a vector quantity expressed as the gradient of the electrostatic potential, which is a scalar quantity denoted by or occasionally , equal to the electric potential energy o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyroelectricity
Pyroelectricity (from the two Greek words ''pyr'' meaning fire, and electricity) is a property of certain crystals which are naturally electrically polarized and as a result contain large electric fields. Pyroelectricity can be described as the ability of certain materials to generate a temporary voltage when they are heated or cooled. The change in temperature modifies the positions of the atoms slightly within the crystal structure, such that the polarization of the material changes. This polarization change gives rise to a voltage across the crystal. If the temperature stays constant at its new value, the pyroelectric voltage gradually disappears due to leakage current. The leakage can be due to electrons moving through the crystal, ions moving through the air, or current leaking through a voltmeter attached across the crystal. Explanation Pyroelectric charge in minerals develops on the opposite faces of asymmetric crystals. The direction in which the propagation of the char ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lighters
A lighter is a portable device which creates a flame, and can be used to ignite a variety of items, such as cigarettes, gas lighter, fireworks, candles or campfires. It consists of a metal or plastic container filled with a flammable liquid or compressed gas, a means of ignition to produce the flame, and some provision for extinguishing the flame. Alternatively, a lighter can be powered by electricity, using an electric arc or heating element to ignite the target. History The first lighters were converted flintlock pistols that used gunpowder. In 1662 the Turkish traveller Evliya Çelebi visited Vienna as a member of an Ottoman diplomatic mission and admired the lighters being manufactured there: “Enclosed in a kind of tiny box are tinder, a steel, sulphur and resinous wood. When struck just like a firearm wheel the wood bursts into flame. This is useful for soldiers on campaign.” One of the first lighters was invented by a German chemist named Johann Wolfgang Döbereiner ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electronic Drum
Electronic drums is a modern electronic musical instrument, primarily designed to serve as an alternative to an acoustic drum kit. Electronic drums consist of an electronic sound module which produces the synthesized or sampled percussion sounds and a set of 'pads', usually constructed in a shape to resemble drums and cymbals, which are equipped with electronic sensors (or triggers) to send an electronic signal to the sound module which outputs a sound to the player. Like regular drums, the pads are struck by drum sticks and they are played in a similar manner to an acoustic drum kit, albeit some differences in the drumming experience. The electronic drum (pad/triggering device) is usually sold as part of an electronic drum kit, consisting of a set of drum pads mounted on a stand or rack in a configuration similar to that of an acoustic drum kit layout, with rubberized (Roland corporation, Roland, Yamaha Corporation, Yamaha, Alesis, for example) or specialized acoustic/electronic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trigger (drums)
In drumming, a trigger is an electronic transducer that can be attached to a drum, cymbal or other instrument to enable it to control an electronic drum unit or similar device. Specialised triggers are produced for specific instruments. A snare drum trigger, for example, will often have two channels, one each for the rim and head, while a tom-tom drum trigger usually needs to only register strokes to the drum head. Drum triggers gained great attention in the beginning of the 1990s, being extensively used on bass drums in heavy metal music. The advantage of using drum triggers is that potential problems associated with using microphones can be overcome by triggering pre-recorded samples. It is commonly quoted that less effort is required from the drummer when using drum triggers. The drum module to which the trigger is connected can be adjusted to accommodate a range of volumes, thus preserving the dynamic range of the drummer's playing. Triggers have a greater use in live perfor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Guitar Amplifier
A guitar amplifier (or amp) is an electronic device or system that strengthens the electrical signal from a pickup on an electric guitar, bass guitar, or acoustic guitar so that it can produce sound through one or more loudspeakers, which are typically housed in a wooden cabinet. A guitar amplifier may be a standalone wood or metal cabinet that contains only the power amplifier (and preamplifier) circuits, requiring the use of a separate speaker cabinet–or it may be a "combo" amplifier, which contains both the amplifier and one or more speakers in a wooden cabinet. There is a wide range of sizes and power ratings for guitar amplifiers, from small, lightweight "practice amplifiers" with a single 6-inch speaker and a 10-watt amp to heavy combo amps with four 10-inch or four 12-inch speakers and a 100-watt amplifier, which are loud enough to use in a nightclub or bar performance. Guitar amplifiers can also modify an instrument's tone by emphasizing or de-emphasizing certain ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pickup (music Technology)
A pickup is a transducer that captures or senses mechanical vibrations produced by musical instruments, particularly stringed instruments such as the electric guitar, and converts these to an electrical signal that is amplified using an instrument amplifier to produce musical sounds through a loudspeaker in a speaker enclosure. The signal from a pickup can also be recorded directly. Most electric guitars and electric basses use magnetic pickups. Acoustic guitars, upright basses and fiddles often use a piezoelectric pickup. Magnetic pickups A typical magnetic pickup is a transducer (specifically a variable reluctance sensor) that consists of one or more permanent magnets (usually alnico or ferrite) wrapped with a coil of several thousand turns of fine enameled copper wire. The magnet creates a magnetic field which is focused by the pickup's pole piece or pieces. The permanent magnet in the pickup magnetizes the guitar string above it. This causes the string to generate a ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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