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Complex Oxide
A complex oxide is a chemical compound that contains oxygen and at least two other elements (or oxygen and just one other element that's in at least two oxidation states). Complex oxide materials are notable for their wide range of magnetic and electronic properties, such as ferromagnetism, ferroelectricity, and high-temperature superconductivity. These properties often come from their strongly correlated electrons in d or f orbitals. Natural occurrence Many minerals found in the ground are complex oxides. Commonly studied mineral crystal families include spinels and perovskites. Applications Complex oxide materials are used in a variety of commercial applications. Magnets Magnets made of the complex oxide ferrite are commonly used in transformer cores and in inductors. Ferrites are ideal for these applications because they are magnetic, electrically insulating, and inexpensive. Transducers and actuators Piezoelectric transducers and actuators are often made of the c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Piezoelectric
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 stress (mechanics), mechanical stress. The piezoelectric effect results from the linear electromechanical interaction between the mechanical and electrical states in crystalline materials with no centrosymmetry, inversion symmetry. The piezoelectric effect is a reversible process (thermodynamics), reversible process: List of piezoelectric materials, materials exhibiting the piezoelectric effect also exhibit the reverse piezoelectric effect, the internal generation of a mechanical strain resulting from an applied electric field. For example, lead zirconate titanate crystals will generate measurable piezoelectricity when their static structure is Deformation (physics), deformed by about 0.1% of the original dimension. Conversely, those same crystals will change about 0.1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Anode
An anode usually is an electrode of a polarized electrical device through which conventional current enters the device. This contrasts with a cathode, which is usually an electrode of the device through which conventional current leaves the device. A common mnemonic is ACID, for "anode current into device". The direction of conventional current (the flow of positive charges) in a circuit is opposite to the direction of electron flow, so (negatively charged) electrons flow from the anode of a galvanic cell, into an outside or external circuit connected to the cell. For example, the end of a household battery marked with a "+" is the cathode (while discharging). In both a galvanic cell and an electrolytic cell, the anode is the electrode at which the oxidation reaction occurs. In a galvanic cell the anode is the wire or plate having excess negative charge as a result of the oxidation reaction. In an electrolytic cell, the anode is the wire or plate upon which excess positive charge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Electrolyte
An electrolyte is a substance that conducts electricity through the movement of ions, but not through the movement of electrons. This includes most soluble Salt (chemistry), salts, acids, and Base (chemistry), bases, dissolved in a polar solvent like water. Upon dissolving, the substance separates into cations and anions, which disperse uniformly throughout the solvent. Solid-state electrolytes also exist. In medicine and sometimes in chemistry, the term electrolyte refers to the substance that is dissolved. Electrically, such a solution is neutral. If an electric potential is applied to such a solution, the cations of the solution are drawn to the electrode that has an abundance of electrons, while the anions are drawn to the electrode that has a deficit of electrons. The movement of anions and cations in opposite directions within the solution amounts to a current. Some gases, such as hydrogen chloride (HCl), under conditions of high temperature or low pressure can also functi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Solid Oxide Fuel Cell
A solid oxide fuel cell (or SOFC) is an Electrochemistry, electrochemical conversion device that produces electricity directly from oxidizing a fuel. Fuel cells are characterized by their electrolyte material; the SOFC has a solid oxide or ceramic electrolyte. Advantages of this class of fuel cells include high combined heat and power efficiency, long-term stability, fuel flexibility, low emissions, and relatively low cost. The largest disadvantage is the high operating temperature which results in longer start-up times and mechanical and chemical compatibility issues. Introduction Solid oxide fuel cells are a class of fuel cells characterized by the use of a solid oxide material as the electrolyte. SOFCs use a solid oxide electrolyte to conduct negative oxygen ions from the cathode to the anode. The electrochemical oxidation of the hydrogen, carbon monoxide or other organic intermediates by oxygen ions thus occurs on the anode side. More recently, proton-conducting SOFCs (PC-S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Ceramic Capacitor
A ceramic capacitor is a fixed-value capacitor where the ceramic material acts as the dielectric. It is constructed of two or more alternating layers of ceramic and a metal layer acting as the electrodes. The composition of the ceramic material defines the electrical behavior and therefore applications. Ceramic capacitors are divided into two application classes: * Class 1 ceramic capacitors offer high stability and low losses for resonant circuit applications. * Class 2 ceramic capacitors offer high volumetric efficiency for buffer, by-pass, and coupling applications. Ceramic capacitors, especially multilayer ceramic capacitors (MLCCs), are the most produced and used capacitors in electronic equipment that incorporate approximately one trillion (1012) pieces per year.Download Ceramic capacitors of special shapes and styles are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Dielectric
In electromagnetism, a dielectric (or dielectric medium) is an Insulator (electricity), electrical insulator that can be Polarisability, polarised by an applied electric field. When a dielectric material is placed in an electric field, electric charges do not flow through the material as they do in an electrical conductor, because they have no loosely bound, or free, electrons that may drift through the material, but instead they shift, only slightly, from their average equilibrium positions, causing dielectric polarisation. Because of Polarisation density, dielectric polarisation, positive charges are displaced in the direction of the field and negative charges shift in the direction opposite to the field. This creates an internal electric field that reduces the overall field within the dielectric itself. If a dielectric is composed of weakly Chemical bond, bonded molecules, those molecules not only become polarised, but also reorient so that their Symmetry axis, symmetry axes a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Barbecue Grill
A barbecue grill or barbeque grill (known as a barbecue in Canada and barbecue or barbie in Australia and New Zealand) is a device that cooks food by applying heat from below. There are several varieties of grills, with most falling into one of three categories: gas-fueled, charcoal, or electric. There is debate over which method yields superior results. History in the Americas Grilling has existed in the Americas since pre-colonial times. The Arawak people of South America roasted meat on a wooden structure called a barbacoa in Spanish. For centuries, the term ''barbacoa'' referred to the wooden structure and not the act of grilling, but it was eventually modified to "barbecue". It was also applied to the pit-style cooking techniques now frequently used in the southeastern United States. Barbecue was originally used to slow-cook hogs; however, different ways of preparing food led to regional variations. Over time, other foods were cooked in a similar fashion, with hamburge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Lighter
A lighter is a portable device which uses mechanical or electrical means to create a controlled flame, and can be used to ignite a variety of flammable items, such as cigarettes, butane gas, fireworks, candles, or campfires. A lighter typically consists of a metal or plastic container filled with a flammable liquid, a compressed flammable gas, or in rarer cases a flammable solid (e.g. rope in a trench lighter); a means of ignition to produce the flame; and some provision for extinguishing the flame or else controlling it to such a degree that users may extinguish it with their breath. Alternatively, a lighter can be one that uses electricity to create an electric arc using the created plasma as the source of ignition or a heating element can be used in a similar vein to heat the target to its ignition temperatures, as first formally used by Friedrich Wilhelm Schindler to light cigars and now more commonly seen incorporated into the automobile auxiliary power outlet to ig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Piezo Ignition
Piezo ignition is a type of ignition that is used in portable camping stoves, gas grills and some lighters. Piezo ignition uses the principle of piezoelectricity, which is the electric charge that accumulates in some materials in response to mechanical deformation. It consists of a small, spring-loaded hammer which, when a button is pressed, hits a crystal of PZT. This sudden forceful deformation produces a high voltage and subsequent electrical discharge, which ignites the gas. No external electric connection is required, though wires are sometimes used to place the sparking location away from the crystal itself. Piezo ignition systems can be operated by either a lever, push-button or built into the control knob. An electric spark is usually generated once per turn of the knob or press of the button. Eventually, the crystal will no longer be able to emit an electric discharge. However, this takes a long time — piezoelectric igniters usually stop sparking after several te ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Microphone
A microphone, colloquially called a mic (), or mike, is a transducer that converts sound into an electrical signal. Microphones are used in many applications such as telephones, hearing aids, public address systems for concert halls and public events, motion picture production, live and recorded audio engineering, sound recording, two-way radios, megaphones, and radio and television broadcasting. They are also used in computers and other electronic devices, such as mobile phones, for recording sounds, speech recognition, Voice over IP, VoIP, and other purposes, such as Ultrasonic transducer, ultrasonic sensors or knock sensors. Several types of microphone are used today, which employ different methods to convert the air pressure variations of a sound wave to an electrical signal. The most common are the dynamic microphone, which uses a coil of wire suspended in a magnetic field; the condenser microphone, which uses the vibrating Diaphragm (acoustics), diaphragm as a capacitor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Ultrasound
Ultrasound is sound with frequency, frequencies greater than 20 Hertz, kilohertz. This frequency is the approximate upper audible hearing range, limit of human hearing in healthy young adults. The physical principles of acoustic waves apply to any frequency range, including ultrasound. Ultrasonic devices operate with frequencies from 20 kHz up to several gigahertz. Ultrasound is used in many different fields. Ultrasonic devices are used to detect objects and measure distances. Ultrasound imaging or sonography is often used in medicine. In the nondestructive testing of products and structures, ultrasound is used to detect invisible flaws. Industrially, ultrasound is used for cleaning, mixing, and accelerating chemical processes. Animals such as bats and porpoises use ultrasound for locating prey and obstacles. History Acoustics, the science of sound, starts as far back as Pythagoras in the 6th century BC, who wrote on the mathematical properties of String instrument ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |