Encyclopedia

Electromagnetic field solver Electromagnetic field solvers (or sometimes just field solvers) are specialized programs that solve (a subset of) Maxwell's equations directly. They form a part of the field of electronic design automation, or EDA, and are commonly used in the design of integrated circuits and printed circuit boards.
Electromagnetic force In physics, the electromagnetic force is the force that the electromagnetic field exerts on electrically charged particles. It is the electromagnetic force that holds electrons and nuclei together in atoms, and which hold atoms together to make molecules.
Electromagnetic forming Electromagnetic forming (EM forming or Magneforming) is a type of high energy rate metal forming process that uses pulsed power techniques to create ultrastrong pulsed magnetic fields to rapidly reshape metal parts. The technique is sometimes called high velocity forming.
Electromagnetic impedance In problems of electromagnetic wave propagation in a transmission medium, the electromagnetic impedance, also known as the intrinsic impedance, is defined as the ratio of the electric to magnetic field amplitudes:
Electromagnetic interference Electromagnetic interference (also called EMI, Radio Frequency Interference, and RFI) is electromagnetic radiation which is emitted by electrical circuits carrying rapidly changing signals, as a by-product of their normal operation, and which causes unwanted signals (interference or noise) to be induced in other circuits. This interrupts, obstructs, or otherwise degrades or limits the effective performance of those other circuits.
Electromagnetic interference control In telecommunication, electromagnetic interference control (EMI) is the control of radiated and conducted energy such that emissions that are unnecessary for system, subsystem, or equipment operation are reduced, minimized, or eliminated.
Electromagnetic mass The electromagnetic mass of an electrically charged object, such as an electron, is the apparent increase in its mass due to its interaction with the electromagnetic field that surrounds it. This interaction is called the field reactionSin-Itiro Tomonaga, Nobel Lecture, May 6, 1966.
Electromagnetic propulsion Electromagnetic propulsion uses the concepts and applications of electromagnets. Technologies that make use of such applications include magnetic levitation technologies, including maglev trains, railguns, and even electromagnetic motors to some degree (though more use is made of the motor principle derived from electromagnets).
Electromagnetic radiation Electromagnetic radiation is generally described as a self-propagating wave in space with electric and magnetic components. These components oscillate at right angles to each other and to the direction of propagation, and are in phase with each other.
Electromagnetic radiation hazard Electromagnetic radiation can be classified into ionizing radiation and non-ionizing radiation, based on whether it is capable of ionizing atoms and breaking chemical bonds. Ultraviolet and higher frequencies, such as X-rays or gamma rays are ionizing.
Electromagnetic Reverberation Chamber [look inside the (large) Reverberation Chamber at the Otto-von-Guericke-University Magdeburg, Germany. On the left side is the vertical Mode Stirrer (or Tuner), that changes the electromagnetic boundaries to ensure a (statistically) homogeneous field distribution.
Electromagnetic shielding Electromagnetic shielding is the process of limiting the flow of electromagnetic fields between two locations, by separating them with a barrier made of conductive material. Typically it is applied to enclosures, separating electrical devices from the 'outside world', and to cables, separating wires from the environment the cable runs through.
Electromagnetic spectrum The electromagnetic (EM) spectrum is the range of all possible electromagnetic radiation. Also, the "electromagnetic spectrum" (usually just spectrum) of an object is the frequency range of electromagnetic radiation that it emits, reflects, or transmits.
Electromagnetic survivability In telecommunication, electromagnetic survivability is the ability of a system, subsystem, or equipment to resume functioning without evidence of degradation following temporary exposure to an adverse electromagnetic environment.
Electromagnetic tensor The electromagnetic tensor or electromagnetic field tensor (sometimes called the field strength tensor, Faraday tensor or Maxwell bivector) is a mathematical object that describes the electromagnetic field of a physical system in Maxwell's theory of electromagnetism. The field tensor was first used after the 4-dimensional tensor formulation of special relativity introduced by Hermann Minkowski.
Electromagnetic testing Electromagnetic Testing (ET), as a form of nondestructive testing, is the process of inducing electric currents or magnetic fields or both inside a test object and observing the electromagnetic response. If the test is set up properly, a defect inside the test object creates a measurable response.
Electromagnetic therapy Electromagnetic therapy is a form of alternative medicine which claims to treat disease by applying electromagnetic energy to the body. Proponents of electromagnetic therapy believe that when the body's electromagnetic energies are unbalanced, the electromagnetic fields "disrupt the body's chemical makeup resulting in disease and illness".
Electromagnetic wave equation The electromagnetic wave equation is a second-order partial differential equation that describes the propagation of electromagnetic waves through a medium or in a vacuum. The homogeneous form of the equation, written in terms of either the electric field E or the magnetic field H, takes the form:
Electromagnetically induced transparency Electromagnetically induced transparency (EIT) is a coherent optical nonlinearity which renders a medium transparent over a narrow spectral range within an absorption line. Extreme dispersion is also created within this transparency "window" which leads to "slow light", described below.
Electromagnetism Electromagnetism is the physics of the electromagnetic field; a field encompassing all of space which exerts a force on particles that possess the property of electric charge, and is in turn affected by the presence and motion of those particles.
Electromechanics In engineering, electromechanics combines the sciences of electromagnetism of electrical engineering and mechanics. Mechatronics is the discipline of engineering that combines mechanics, electronics and information technology.
Electrometer An electrometer is an electrical instrument for measuring electric charge or electrical potential difference. There are many different types, ranging from historical hand-made instruments to high-precision electronic devices.
Electromigration Electromigration is the transport of material caused by the gradual movement of the ions in a conductor due to the momentum transfer between conducting electrons and diffusing metal atoms. The effect is only important in applications where high direct current densities are used, such as in microelectronics and related structures.
Electromotive force Electromotive force (emf) is defined as the amount of energy gained per unit charge that passes through a device in the opposite direction to the electric field produced by that device. It is measured in volts.
Electromyography Electromyography (EMG) is a medical technique for evaluating and recording physiologic properties of muscles at rest and while contracting. EMG is performed using an instrument called an electromyograph, to produce a record called an electromyogram.
Electron The electron is a fundamental subatomic particle that carries a negative electric charge. It is a spin-½ lepton that participates in electromagnetic interactions, and its mass is less than one thousandth of that of the smallest atom.
Electron (computer hacker) Electron was the computer handle of Richard Jones, a member of an underground hacker community called The Realm. Jones, born in June 1969, was one of three members of the group arrested in simultaneous raids by the Australian Federal Police in Melbourne, Australia, on April 2, 1990.
Electron aufbau The Aufbau Principle states that electrons fill up the orbitals in the increasing order of the orbital energy. Electrons fill up orbitals which have lowest energy and this is the configuration that the electrons have in the ground state of the atom.
Electron avalanche An electron avalanche is a process in which a number of free electrons in a medium (usually a gas) are subjected to strong acceleration by an electric field, ionizing the mediums' atoms by collision (called impact ionization), thereby forming "new" electrons to undergo the same process in successive cycles. Electron avalanches are essential to the dielectric breakdown process within gases.
Electron backscatter diffraction Electron backscatter diffraction (EBSD), also known as backscatter Kikuchi diffraction (BKD) is a microstructural-crystallographic technique used to elucidate the crystallographic texture or preferred orientation of any crystalline or polycrystalline materials. EBSD can be used to index and identify the seven crystal systems, and as such it is applied to crystal orientation mapping, defect studies, phase identification, grain boundary and morphology studies, regional heterogeneity investigations, material discrimination, and using complimentary techniques, physico-chemical identification.
Electron beam induced current Electron beam induced current (EBIC) is a semiconductor analysis technique performed in a scanning electron microscope (SEM) or scanning transmission electron microscope (STEM). It is used to identify buried junctions or defects in semiconductors, or to examine minority carrier properties.
Electron beam physical vapor deposition Electron Beam Physical Vapor Deposition or EBPVD is a form of physical vapor deposition in which a target anode is bombarded with an electron beam given off by a charged tungsten filament under high vacuum. The electron beam causes atoms from the target to transform into the gaseous phase.
Electron beam technology In electron beam technology, an electron beam is applied to do some useful work. Given the wide range of energies and intensities of electron beams that can be generated, the range of applications is equally large:
Electron beam texturing Electron beam texturing (EBT) is a technology used to apply roughness to the surface of rolling mill cylinders by impinging the surface of these cylinders with a modulated electron beam. The beam locally melts the surface of the cylinder, producing crater-like depressions.
Electron beam tomography Electron beam tomography is a specific form of computed axial tomography (CAT or CT) in which the X-Ray tube is not mechanically spun in order to rotate the source of X-Ray photons. This different design was explicitly developed to better image heart structures which never stop moving, performing a complex complete cycle of movement with each heart beat.
Electron beam welding Electron beam welding (EBW) is a fusion welding process in which a beam of high-velocity electrons are applied to the materials being joined. The workpieces melt as the kinetic energy of the electrons is transformed into heat upon impact, and the filler metal, if used, also melts to form part of the weld.
Electron bubble An electron bubble is the empty space created around a free electron in a cryogenic gas or liquid, such as neon or helium. They are typically very small, about 20 Angstroms in diameter at 1 atmosphere of pressure.
Electron Beam Prober The Electron Beam Prober (E-beam Prober) is a specialized adaption of a standard Scanning Electron Microscope (SEM) that is used for semiconductor failure analysis. While a standard SEM may be operated in a voltage range of 25KeV to 30KeV, the E-beam Prober typically operates at 1KeV.
Electron capture Electron capture (sometimes called Inverse Beta Decay) is a decay mode for isotopes that will occur when there are too many protons in the nucleus of an atom and insufficient energy to emit a positron; however, it continues to be a viable decay mode for radioactive isotopes that can decay by positron emission. If the energy difference between the parent atom and the daughter atom is less than 1.
Electron capture dissociation In mass spectrometry, electron capture dissociation (ECD) is a method of fragmenting gas phase ions for tandem mass spectrometric analysis (structural elucidation). ECD involves the introduction of low energy electrons to trapped gas phase ions.
Electron cloud Electron cloud is a term used for introducing the concept of wavefunction in low-level pedagogical introductions tomolecular physics, chemistry or quantum chemistry. This idea corresponds to delocated electrons moving or standing like clouds around the atomic or molecular [ This is indeed a better image than the very common image provided by the Bohr model] which commonly leads to a visualisation of electrons travelling around the nuclei along [[orbits like the planets around the sun.
Electron crystallography Electron crystallography is a method to determine the arrangement of atoms in solids using an electron microscope. It can complement X-ray crystallography on proteins (such as membrane proteins), that cannot easily form the large 3-dimensional crystals required for that process.
Electron Cloud (Particle Accelerator) In particle accelerators, a significant problem has arisen involving stray electrons in the accelerator tube. The electron cloud is a gas of floating electrons inside the accelerator tube - which ideally should be a vacuum.
Electron deficiency Electron deficiency occurs when a compound has too few valence electrons for the connections between atoms to be described as covalent bonds. Electron deficient bonds are often better described as 3-center-2-electron bonds.
Electron degeneracy pressure Electron degeneracy pressure is a force caused by the Pauli exclusion principle, which states that two electrons cannot occupy the same quantum state at the same time. This force often sets a limit to how much matter can be squeezed together.
Electron diffraction Electron diffraction is a technique used to study matter by firing electrons at a sample and observing the resulting interference pattern. This phenomenon occurs due to the wave-particle duality, which states that a particle of matter (in this case the incident electron) can be described as a wave.
Electron economy The electron economy is a concept analogous to the hydrogen economy, methanol economy, ethanol economy, zinc economy, lithium economy or liquid nitrogen economy but where the energy vector is electricity instead of hydrogen, methanol etc.
Electron electric dipole moment The electron electric dipole moment (EDM) d_e is, roughly speaking, a measure of the charge distribution within an electron. Within the standard model of elementary particle physics, such a dipole is predicted to be of smaller than 10^{-40} mathrm{ e cm}, where e stands for the elementary charge.
Electron energy loss spectroscopy In electron energy loss spectroscopy (EELS) a material is exposed to a beam of electrons with a known, narrow range of kinetic energies. Some of the electrons will lose energy by inelastic scattering, which is primarily an interaction of the beam electron with an electron in the sample.
Electron excitation Electron excitation is the movement of an electron to a higher energy state. This can either be done by photoexcitation (PE), where the original electron absorbs the photon and gains all the photon's energy or by electrical excitation (EE), where the original electron absorbs the energy of another, energetic electron.
Electron gun An electron gun is a component that produces an electron beam that has a precise kinetic energy, being used in all TVs and monitors which use cathode ray tube technology, and in other instruments, eg. electron microscopes and at the beginning of linear particle accelerators.
Electron hole In solid state physics, an electron hole (usually referred to simply as a hole) is the absence of an electron from the otherwise full valence band. A full (or nearly full) valence band is present in semiconductors and insulators.
Electron microprobe The electron microprobe is an analytical tool used to non-destructively determine the chemical composition of small volumes of solid materials. It uses a high-energy focused beam of electrons to generate X-rays characteristic of the elements present within a sample volumes 1 to 3 micrometres across and can quantitatively analyze elements from boron to plutonium at routine levels as low as 100 parts per million (ppm).
Electron microscope The electron microscope is a type of microscope that uses electrons to create an image of the target. It has much higher magnification or resolving power than a normal light microscope, up to two million times, allowing it to see smaller objects and details.
Electron mobility In physics, electron mobility (or simply, mobility), is a quantity relating the drift velocity of charge carriers to the applied electric field across a material. It also describes the related concept of the net flow of charge carriers.
Electron Phases In physical chemistry, Electron Phases describe the sign (positive or negative) of the wave function, which is a solution to the Schrödinger equation. When two wave functions describing two atomic orbitals on the same atom are combined, a hybrid orbital is created.
Electron shell An electron shell, also known as a main energy level, is a group of atomic orbitals with the same value of the principal quantum number n. Electron shells are made up of one or more electron subshells, or sublevels, which have two or more orbitals with the same angular momentum quantum number l.
Electron spectrometer In an Electron spectrometer, an incoming beam of electrons is bent with electric or magnetic fields. As higher energy electrons will be bent less by the beam, this produces a spatially distributed range of energies.
Electron spectroscopy Electron spectroscopy is an analytical technique to study the electronic structure and its dynamics in atoms and molecules. In general an excitation source such as x-rays, electrons, or synchrotron radiation will eject an electron from an inner-shell orbital of an atom.
Electron spin resonance Electron Paramagnetic Resonance (EPR) or Electron Spin Resonance (ESR) is a spectroscopic technique which detects species that have unpaired electrons, generally meaning that the molecule in question is a free radical if it is an organic molecule, or that it has transition metal ions if it is an inorganic complex. Because most stable molecules have a closed-shell configuration without a suitable unpaired spin, the technique is less widely used than nuclear magnetic resonance (NMR).
Electron spiral toroid Electron Power Systems, Inc. of Acton, MA claims to have developed a technology for maintaining small stable plasma toroids called electron spiral toroids (ESTs) which remain stable in Earth's atmosphere without the use of any special magnetic fields.
Electron tomography Electron Tomography (ET) is a tomography technique for obtained detailed 3D structures of macromolecular objects. In the process, a beam of electrons is passed through the sample at incremental degrees of rotation around the center of the target sample.
Electron toolset The Electron toolset was developed by Obsidian Entertainment and is included in the computer role-playing game Neverwinter Nights 2. It allows people to design their own adventures (known as a module) and distribute them for others who own the game to play.
Electron transfer Electron transfer (ET) is the process by which an electron moves from one atom or molecule to another atom or molecule. ET is a mechanistic description of the thermodynamic concept of redox, wherein the formal oxidation states of both reaction partners change.
Electron transport chain An electron transport chain (also called electron transport system (ETS) or electron transfer chain (ETC)) is a series of membrane-associated electron carriers mediating biochemical reactions that produce Adenosine triphosphate (ATP), which is the energy currency of life. Only two sources of energy are available to living organisms: oxidation-reduction (redox) reactions and sunlight (photosynthesis).
Electron-Cloud Effect The Electron-Cloud Effect (ECE) is a phenomenon associated with particle accelerators. When a charged particle is accelerated in a particle accelerator, the charged particles may disturb stray electrons in the chamber, which in turn generate more electrons when they hit the walls of the accelerator tube - through Secondary emission.
Electron-multiplying CCD An electron-multiplying CCD (EMCCD, also known as an L3Vision CCD, L3CCD or Impactron CCD) is a charge-coupled device in which a gain register is placed between the shift register and the output amplifier. The gain register is split up into a large number of stages.
Electronegativity Electronegativity is a measure of the ability of an atom or molecule to attract electrons in the context of a chemical bond. The type of bond formed is largely determined by the difference in electronegativity between the atoms involved.
Electroneuronography Electroneuronography (ENoG) is a neurological non-invasive test that is used to examine the integrity of a peripheral nerve. It consists of a brief electrical stimulation of the nerve in one point underneath the skin, and at the same time recording the electrical activity (compound action potentials) at another point of the nerve's trajectory in the body.
Electronic art Electronic art is art which makes use of electronic media or, more broadly, refers to technology and/or electronic media. It is related to information art, new media art, video art, interactive art, internet art, and electronic music, among others.
Electronic art music Electronic music has existed, in various forms, for more than a century. Between the time that recording sounds was first made possible and the computer technology of today, a vast amount of change has occurred.
Electronic article Electronic articles are articles in scholarly journals or magazines that can be accessed via electronic transmission. The are a specialized form of electronic document, with a specialized content, purpose, format, metadata, and availability–they consist of individual articles from scholarly journals or magazines (and now sometimes popular magazines), they have the purpose of providing material for academic research and study, they are formatted approximately like printed journal articles, the metadata is entered into specialized databases, such as DOAJ or OACI as well as the databases for the discipline, and they are predominantly available through academic libraries and special libraries, generally at a fixed charge.
Electronic authentication Electronic authentication (E-authentication) is the process of establishing confidence in user identities electronically presented to an information system. E-authentication presents a technical challenge when this process involves the remote authentication of individual people over a network, for the purpose of electronic government and commerce.
Electronic band structure In solid state physics, the electronic band structure (or simply band structure) of a solid describes ranges of energy that an electron is "forbidden" or "allowed" to have. It is due to the diffraction of the quantum mechanical electron waves in the periodic crystal lattice.
Electronic battlefield The Electronic Battlefield was a concept of synergizing popular series of computer simulation games with the effect of letting players of different games oppose each other in online play. It was most prominent in then 1990s, especially with the introduction of Spectrum Holobyte's Falcon 3.
Electronic bill payment Electronic bill payment is a feature of online banking, similar in its effect to a giro, allowing a depositor to send money from his demand account to a creditor or vendor such as a public utility or a department store to be credited against a specific account. The payment is optimally executed electronically in real time, though some financial institutions or payment services will wait until the next business day to send out the payment.
Electronic brakeforce distribution Electronic brakeforce distribution (EBD) is an automobile brake technology that automatically varies the amount of force applied to each of a vehicle's brakes, based on road conditions, speed, loading, etc. Often coupled with anti-lock braking systems, EBD can apply more or less braking pressure to each wheel in order to maximize stopping power.
Electronic Battleship: Advanced Mission Electronic Battleship Advanced Mission is a commercial variant of the classic game Battleship published by Milton Bradley. The objective, like all other versions of the game, is to sink you opponent's fleet of five ships.
Electronic Benefit Transfer Electronic Benefit Transfer (EBT) is an electronic system in the United States that allows state governments to provide benefits to authorized recipients via a plastic debit card. Common benefits provided via EBT are typically sorted into two general categories: Food Stamp and Cash benefits.
Electronic Bill Presentment and Payment Electronic Bill Presentment and Payment (EBPP) - also known as ebilling or Electronic Invoice Presentment and Payment (EIPP) - is the electronic delivery and presentation of statements, bills, invoices, and related information sent by a company to its customers. Certain EBPP applications also provide the ability to electronically settle payment for goods or services.
Electronic Broking Services Electronic Broking Services (EBS) was created by a partnership of the world's largest foreign exchange (FX) market making banks. Approximately USD 145 billion in spot foreign exchange transaction, 700,000 oz in gold and 7 million oz in silver is traded every day over the EBS Spot Dealing System.
Electronic calendar Packages are available that enable users to use electronic versions of a variety of office tools such as calendar, appointment book, address book and contact list. These tools are an extension of many of the features provided by time management software such as desk accessory packages and mainframe office automation systems.
Electronic civil disobedience Electronic civil disobedience, also known as ECD or cyber civil disobedience, can refer to any type of civil disobedience in which the participants use information technology to carry out their actions. Generally speaking, electronic civil disobedience involves the Internet.
Electronic colonialism Electronic colonialism theory was first started by Tom McPhail, a Canadian who began his career with Marshall McLuhan. Following a posting with UNESCO in Paris, McPhail wrote a book for SAGE entitiled Electronic Colonialism in the early 1980s.
Electronic color code The electronic color code discussed here is used to indicate the values or ratings of electronic components, very commonly for resistors, but also for capacitors, inductors, and others. A separate code, the 25-pair color code, is used to identify wires in a cable or bundle.
Electronic commerce Electronic commerce (also referred to as EC, e-commerce or ecommerce) consists primarily of the distributing, buying, selling, marketing, and servicing of products or services over electronic systems such as the Internet and other computer networks. The information technology industry might see it as an electronic business application aimed at commercial transactions; in this context, it can involve electronic funds transfer, supply chain management, e-marketing, online marketing, online transaction processing, electronic data interchange (EDI), automated inventory management systems, and automated data collection systems.
Electronic correlation Electronic correlation refers to the interaction between electrons in a quantum system whose electronic structure is being considered. The term correlation stems from mathematical statistics and means that two distribution functions, f(x) and g(y), are not independent of each other.
Electronic counter-countermeasures Electronic counter-countermeasures (ECCM) describes a variety of practices which attempt to reduce or eliminate the effect of Electronic countermeasures (ECM) on electronic sensors aboard vehicles, ships and aircraft and weapons such as missiles. ECCM is also known as Electronic Protective Measures (EPM), chiefly in Europe.
Electronic countermeasures Electronic countermeasures (ECM) are a subsection of electronic warfare which includes any sort of electrical or electronic device designed to fool radar, sonar, or other detection systems. It may be used both offensively or defensively in any method to deny targeting information to an enemy.
Electronic Catalogues An electronic catalogue is designed to present products to customers or partners all over the world via the internet. The electronic catalogue provides more detailed information about the products the company has to offer, including real-time inventory status, photographs, product specifications, product instructions, safety procedures, and video demonstrations.
Electronic Contract Manufacturing Electronic Contract Manufacturing (ECM) is a is term used for companies that offer contracts for electronic assembly for another company. For instance, instead of attempting to manufacture complex circuit boards themselves OEM companies often outsource their manufacturing operations to ECM companies.
Electronic Cultural Atlas Initiative The Electronic Cultural Atlas Initiative is a Digital Humanities initiative involving numerous academic professors and institutions around the world with the stated goal of creating a networked digital atlas by creating tools and setting standards for dynamic, digital maps.
Electronic dance music Electronic dance music (EDM) is a broad set of percussive music genres that largely inherit from 1970s disco music and, to some extent, the experimental pop music of Kraftwerk. Such music was originally borne of and popularized via regional nightclub scenes in the 1980s.
Electronic data processing Electronic data processing (also: Information Technology or IT) can refer to the use of automated methods to process commercial data. Typically, this uses relatively simple, repetitive activities to process large volumes of similar information.
Electronic deception In telecommunication, the term electronic deception means the deliberate radiation, reradiation, alteration, suppression, absorption, denial, enhancement, or reflection of electromagnetic energy in a manner intended to convey misleading information and to deny valid information to an enemy or to enemy electronics-dependent weapons.
Electronic design automation Electronic design automation (EDA) is the category of tools for designing and producing electronic systems ranging from printed circuit boards (PCBs) to integrated circuits. This is sometimes referred to as ECAD (electronic computer-aided design) or just CAD.
Electronic discovery Electronic discovery, or "e-discovery", refers to discovery in civil litigation which deals with information in electronic form. In this context elecronic form is the representation of information as binary numbers.
Electronic Data Interchange Electronic Data Interchange (EDI) is a set of standards for structuring information to be electronically exchanged between and within businesses, organizations, government entities and other groups. The standards describe structures that emulate documents, for example purchase orders to automate purchasing.
Electronic Data Systems Electronic Data Systems (EDS) (, ) is a global business and technology services company that defined the outsourcing business when it was established in 1962 by Ross Perot. Headquartered in Plano, Texas, General Motors acquired the company in 1984, although it became an independent company again in 1996.
Electronic Defense Laboratories Electronic Defense Laboratories, located in Mountain View, California, known in the 1960s and 1970s simply as "EDL", was a semi-private corporate entity essentially funded by the Department of Defense, but drew heavily on civilian scientific expertise from firms such as Sylvania Electronics.

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