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electrical conductivity ... electron affinity

electrical conductivity: (from the article "high-pressure phenomena") ...environment entails considerable experimental difficulties, especially those associated with attaching leads to pressurized samples or detecting small signals from the experiment. Nevertheless, electric conductivities of numerous materials at high pressures ...
electrical conductor: (from the article "electricity") Materials are classified as conductors, insulators, or semiconductors according to their electric conductivity. The classifications can be understood in atomic terms. Electrons in an atom can have only certain well-defined ...
electrical contact layer: (from the article "solar cell") ...three energy-conversion layers below the antireflection layer are the top junction layer, the absorber layer, which constitutes the core of the device, and the back junction layer. Two additional electrical ...
electrical counterweight-assisted hoist: (from the article "stage design") ...in turn, be divided into several categories defined by the type of hoist used. Some systems use electricity to provide the pulling power but still require counterbalancing; this type is ...
electrical defibrillation: (from the article "cardiovascular disease") The use of cardiopulmonary resuscitation (CPR) coupled with electrical defibrillation (the use of electrical shocks), if applied within a few minutes of the sudden death episode, may successfully resuscitate the ...
electrical discharge: (from the article "animal communication") A number of fishes that live in muddy waters produce regular patterns of electrical discharges as an active sensory system (active in the same sense as a bat's sonar scanning ...
electrical double layer: region of molecular dimension at the boundary of two substances across which an electrical field exists. The substances must each contain electrically charged particles, such as electrons, ions, or molecules ... [1 Related Articles]
electrical firing: (from the article "explosive") The principal advantages of electric over fuse firing are exact control of the time when the blast is initiated, the simultaneous firing of a number of shots, if that is ...
electrical hygrometer: (from the article "hygrometer") Electrical hygrometers measure the change in electrical resistance of a thin layer of lithium chloride, or of a semiconductor device, as the humidity changes. Other hygrometers sense changes in weight, ...
electrical impedance: measure of the total opposition that a circuit or a part of a circuit presents to electric current. Impedance includes both resistance and reactance (qq.v.). The resistance component arises from ... [6 Related Articles]
Electrical Research Products, Incorporated: (from the article "motion picture, history of the") ...earned. The major film companies then wasted no time. By May 1928 virtually every studio in Hollywood, major and minor, was licensed by Western Electric's newly created marketing subsidiary, Electrical ...
electrical shock: the perceptible and physical effect of an electrical current that enters the body. The shock may range from an unpleasant but harmless jolt of static electricity, received after one has ... [3 Related Articles]
electrical steel: (from the article "steel") An important group of steels, necessary for the generation and transmission of electrical power, is the high-silicon electrical steels. Electromagnets for alternating current are always made by laminating many thin ...
electrical stimulation: (from the article "pain") Some pain may be treated by electrical stimulation through electrodes placed on the skin above the painful area. The stimulation of additional peripheral nerve endings has an inhibitory effect on ...
electrical stunning: (from the article "meat processing") The three most common methods of stunning are mechanical, electrical, and carbon dioxide (CO₂) gas. The end result of each method is to render the animal unconscious. Mechanical stunning involves ...
Electrical Supply Commission: (from the article "South Africa") Nearly all of South Africa's electricity is produced thermally, almost entirely from coal. Most electric power is generated by ESKOM at huge stations in Mpumalanga. Synthetic fuel derived from coal ...
electrical system: (from the article "automobile") The electrical system comprises a storage battery, generator, starting (cranking) motor, lighting system, ignition system, and various accessories and controls. Originally, the electrical system of the automobile was limited to ...
electrical tachometer: (from the article "tachometer") Electrical tachometers are of several types. The eddy-current, or drag, type is widely used in automobile speedometers; a magnet rotated with the shaft being measured produces eddy currents that are ...
electrical therapy: (from the article "aversion therapy") ...pattern by conditioning the person to associate the behaviour with an undesirable stimulus. The chief stimuli used in the therapy are electrical, chemical, or imagined aversive situations. In the electrical ...
electrical transducer: (from the article "transducer") Electrical transducers may be classified as active or passive. The active transducers generate electric current or voltage directly in response to stimulation. An example is the thermocouple; here, the fact ...
electrical transmission: (from the article "nervous system") ...are next to other neurons and muscle cells (see the section The nerve cell: The neuron). At this point there exist two methods for transmitting the action potential from one ...
Electrical, Electronic, Telecommunication and Plumbing Union: (from the article "Amalgamated Engineering and Electrical Union") the leading trade union in the manufacturing sector of the United Kingdom, created in 1992 through the merger of the Amalgamated Engineering Union (AEU) with the Electrical, Electronic, Telecommunication and ...
electrical-discharge machining: (from the article "machine tool") EDM involves the direction of high-frequency electrical spark discharges from a graphite or soft metal tool, which serves as an electrode, to disintegrate electrically conductive materials such as hardened steel ...
electrical-resistance thermometer: (from the article "thermometer") Electrical-resistance thermometers characteristically use platinum and operate on the principle that electrical resistance varies with changes in temperature. Thermocouples are among the most widely used industrial thermometers. They are composed ...
electrically alterable read-only memory: (from the article "computer memory") EPROM (erasable programmable ROM), EAROM (electrically alterable ROM), and flash memory are types of nonvolatile memories that are rewritable, though the rewriting is far more time-consuming than reading. They are ...
electrically programmable read-only memory: (from the article "computer memory") EPROM (erasable programmable ROM), EAROM (electrically alterable ROM), and flash memory are types of nonvolatile memories that are rewritable, though the rewriting is far more time-consuming than reading. They are ...
electricity: phenomenon associated with stationary or moving electric charges. Electric charge is a fundamental property of matter and is borne by elementary particles. In electricity the particle involved is the electron, ... [41 Related Articles]
Electricity Commission of New South Wales: (from the article "New South Wales") The Electricity Commission of New South Wales owns power stations and coal mines. It generates and transmits electricity, which it sells wholesale to county councils and other local government bodies, ...
electricity grid: (from the article "Jamaica") Jamaica made a major move to expand its renewable energy program in July when independent power producers were allowed to bid for power contracts with the national grid, using nonhydrocarbon ...
electrified fence: (from the article "fence") Electrified fences, frequently a single strand of barbed wire, are sometimes used for temporary confinement of animals. A mild shock is given to the animal at intervals of a few ...
electro-float process: (from the article "industrial glass") ...introduced in 1959 the float glass process, which altogether eliminated the need for grinding and polishing. (The float process is described in Glass forming: Flat glass.) A further development, the ...
electro-optic phenomenon: (from the article "electricity") The index of refraction n of a transparent substance is related to its electric polarizability and is given by n² = 1 + chi_e/epsilon₀. As discussed earlier, chi_e is the ...
electro-optical ceramics: (from the article "optical ceramics") Electro-optical ceramics are materials that combine optical transparency with voltage-variable optical, or electro-optical (EO), behaviour. Single-crystal EO materials include lithium niobate (LiNbO₃) and lithium tantalate (LiTaO₃); polycrystalline EO materials include ...
electro-optical transmitter: (from the article "telecommunications media") The efficiency of an electro-optical transmitter is determined by many factors, but the most important are the following: spectral linewidth, which is the width of the carrier spectrum and is ...
electro-osmosis: (from the article "electrophoresis") ...charged particles in a fluid under the influence of an electric field. If the liquid rather than the particles is set in motion-e.g., through a fixed diaphragm-the phenomenon is called ...
electroacoustic transducer: (from the article "electromechanical transducer") any type of device that either converts an electrical signal into sound waves (as in a loudspeaker) or converts a sound wave into an electrical signal (as in the microphone). ...
electrocardiography: method of graphic tracing (electrocardiogram; ECG or EKG) of the electric current generated by the heart muscle during a heartbeat. The tracing is recorded with an electrocardiograph (actually a relatively ... [6 Related Articles]
electrocatalysis: (from the article "electrochemical reaction") The problems related to the increase of rates of electrochemical reactions, or, to put it another way, the decrease of overpotential, needed to perform reactions at a given rate are ...
electrocautery: (from the article "surgery") ...tied around the bleeding vessels. Absorbent sterile napkins called sponges, made of a variety of natural and synthetic materials, are used for drying the field. Bleeding may also be controlled ...
electroceramics: category of advanced ceramic materials that are employed in a wide variety of electric, optical, and magnetic applications. In contrast to traditional ceramic products such as brick and tile, which ...
electrochemical analysis: (from the article "analysis") The second major category of instrumental analysis is electroanalysis. The electroanalytical methods use electrically conductive probes, called electrodes, to make electrical contact with the analyte solution. The electrodes are used ...
electrochemical corrosion: (from the article "materials testing") ...causes problems in a structure; for example, steel bolts in an aluminum framework may, in the presence of rain or fog, form multiple galvanic cells at the point of contact ...
electrochemical dualism: (from the article "Berzelius, Jons Jacob") Berzelius is best known for his system of electrochemical dualism. The electrical battery, invented in 1800 by Alessandro Volta and known as the voltaic pile, provided the first experimental source ...
electrochemical machining: (from the article "machine tool") ECM resembles electroplating in reverse. In this process metal is dissolved from a workpiece with direct current at a controlled rate in an electrolytic cell. The workpiece serves as the ...
electrochemical reaction: any process either caused or accompanied by the passage of an electric current and involving in most cases the transfer of electrons between two substances-one a solid and the other ... [5 Related Articles]
electrochemiluminescence: (from the article "analysis") ...method is atomic emission spectrometry. If a chemical reaction is used to initiate the luminescence, the technique is chemiluminescence; if an electrochemical reaction causes the luminescence, it is electrochemiluminescence.
electrochemistry: branch of chemistry concerned with the relation between electricity and chemical change. Many spontaneously occurring chemical reactions liberate electrical energy, and some of these reactions are used in batteries and ... [4 Related Articles]
electrocochleogram: (from the article "ear, human") ...or others who are unable to cooperate in standard audiometric tests must be measured, their thresholds for pure tones can be established by electrophysiological means. One type of test is ...
electrocrystallization: (from the article "electrochemical reaction") Deposition of metals and other substances at electrodes as a consequence of an electrode process exhibits a number of specific features. The electrode process is followed by crystal building, and ...
electrocution: method of execution in which the condemned person is subjected to a heavy charge of electric current.
electrocyclic reaction: (from the article "reaction mechanism") In a third class of additions, both portions of the attacking reagent combine simultaneously with the substrate. Reactions of this kind sometimes retain predominantly electrophilic or predominantly nucleophilic character, as ...
electrode: electric conductor, usually metal, used as either of the two terminals of an electrically conducting medium; it conducts current into and out of the medium, which may be an electrolytic ... [15 Related Articles]
electrodeless lamp: (from the article "spectroscopy") ...in the form of discrete lines. The Geissler discharge tube, such as the neon lamp commonly used in advertising signs, is an example of such a source. Other examples are ...
electrodeposition: (from the article "integrated circuit") Two more chemical methods of deposition are electrodeposition (or electroplating) and thermal oxidation. In the former the substrate is given an electrically conducting coating and placed in a liquid solution ...
electrodialysis: (from the article "Separations based on rate phenomena") ...migration resulting from a concentration difference on the two sides of the membrane. In ultrafiltration, this diffusion through the membrane is accelerated by means of a pressure difference. In electrodialysis, ...
electrodics: (from the article "electrochemical reaction") ...i.e., reactions not in equilibrium and not totally reversible. From about 1950 the study of electrified interfaces, with special reference to the study of the transfer of electrons (called electrodics), ...
electrodynamic ammeter: (from the article "ammeter") Ammeters vary in their operating principles and accuracies. The D'Arsonval-movement ammeter measures direct current with accuracies of from 0.1 to 2.0 percent. The electrodynamic ammeter uses a moving coil rotating ...
electrodynamics: (from the article "electromagnetism") Foundations of electrochemistry and electrodynamicshistory of physical sciencesphysical scienceElectricity and magnetism...The Danish physicist Hans Christian Orsted's discovery, in 1820, of ...
electroencephalography: technique for recording and interpreting the electrical activity of the brain. The nerve cells of the brain generate electrical impulses that fluctuate rhythmically in distinct patterns. In 1929 Hans Berger ... [10 Related Articles]
Electrofax: (from the article "electrophotography") A proprietary process known as Electrofax employs a photographic paper coated with a dielectric layer; the entire charging, exposure, and development process is thus effected directly on the paper itself.
electroforming: making duplicates by electroplating metal onto a mold of an object, then removing the mold. Intricate surface details are exactly reproduced by this process, which is used to make masters ...
electrofulguration: (from the article "colorectal cancer") ...be treated by removing only the cancerous polyp or polyps, the cancer plus surrounding tissues, or larger sections of the rectum. Some cancers may be removed by burning them in ...
electrogalvanizing: (from the article "steel") Electrolytic galvanizing lines have similar entry and exit sections, but they deposit zinc in as many as 20 consecutive electrolytic coating cells. Of the several successful cell designs, the simple ...
electrogasdynamics: study of the forces produced by the motion of electrically charged particles (ions) carried by an insulating gas flowing through an electric field. See also magnetohydrodynamic power generator.
electrogravimetry: (from the article "analysis") This method employs an electric current to deposit a solid on an electrode from a solution. Normally the deposit is a metallic plate that has formed from the corresponding metallic ...
electrojet: streaming movement of charged particles in the ionosphere. The term is limited by some to those flow patterns that contain a significant proportion of neutral gases, but highly concentrated, laterally ... [3 Related Articles]
electroless plating: nonelectrical plating of metals and plastics to achieve uniform coatings by a process of controlled autocatalytic (self-continuing) reduction. Discovered in 1944 by A. Brenner and G.E. Riddell, electroless plating involves ...
electroluminescence: production of light by the flow of electrons, as within certain crystals. Electroluminescence is one of the few instances in which a direct conversion of electric energy into visible light ... [3 Related Articles]
electroluminescent lamp: (from the article "lamp") The electroluminescent lamp, another semiconductor lamp, consists of a flat-plate capacitor with a phosphor (similar to those used with fluorescent lamps) in the dielectric; it is used with alternating current. ...
electrolysis: process by which electric current is passed through a substance to effect a chemical change. The chemical change is one in which the substance loses or gains an electron (oxidation ... [26 Related Articles]
electrolyte: in chemistry and physics, substance that conducts electric current as a result of a dissociation into positively and negatively charged particles called ions, which migrate toward and ordinarily are discharged ... [14 Related Articles]
electrolyte balance: (from the article "burn") ...volume is lost to the circulation, insufficient blood returns to the heart for it to maintain blood pressure. And the loss of salts, particularly sodium and potassium salts, not only ...
electrolytic cell: any device in which electrical energy is converted to chemical energy, or vice versa. Such a cell typically consists of two metallic or electronic conductors (electrodes) held apart from each ... [7 Related Articles]
electrolytic dissociation: (from the article "acid-base reaction") The whole subject of acid-base chemistry acquired a new look and a quantitative aspect with the advent of the electrolytic dissociation theory propounded by Wilhelm Ostwald and Svante August Arrhenius ...
electrolytic smelting: (from the article "metallurgy") Smelting is also carried out by the electrolytic dissociation, at high temperatures, of a liquid metallic chloride compound (as is done with magnesium) or of a metallic oxide powder dissolved ...
electrolytic solution: (from the article "liquid") Classes of solutionsliquidSolutions of electrolytesNear the end of the 19th century, the properties of electrolyte solutions were investigated extensively by ...
electromagnet: device consisting of a core of magnetic material surrounded by a coil through which an electric current is passed to magnetize the core. An electromagnet is used wherever controllable magnets ... [4 Related Articles]
electromagnetic field: a property of space caused by the motion of an electric charge. A stationary charge will produce only an electric field in the surrounding space. If the charge is moving, ... [9 Related Articles]
electromagnetic induction: (from the article "induction, electromagnetic") in physics, the induction of an electromotive force in a circuit by varying the magnetic flux linked with the circuit. See Faraday's law of induction.classical radiation theory
electromagnetic lens: (from the article "microscope") Early microscopes relied on electrostatic lenses, but modern instruments use electromagnetic lenses. These consist of a solenoid of wire together with a magnetic pole piece that creates and concentrates a ...
electromagnetic oscillograph: (from the article "oscillograph") instrument for indicating and recording time-varying electrical quantities, such as current and voltage. The two basic forms of the instrument in common use are the electromagnetic oscillograph and the cathode-ray ...
electromagnetic penetration depth: (from the article "superconductivity") ...for one of the two men who discovered it. Its discovery made it possible to formulate, in 1934, a theory of the electromagnetic properties of superconductors that predicted the existence ...
electromagnetic pulse: (from the article "nuclear weapon") A nuclear electromagnetic pulse (EMP) is the time-varying electromagnetic radiation resulting from a nuclear explosion. The development of the EMP is shaped by the initial nuclear radiation from the explosion-specifically, ...
electromagnetic pump: (from the article "pump") These can be used only to pump fluids that are good electrical conductors. The pipe carrying the fluid is placed in a magnetic field and a current passed crosswise through ...
electromagnetic radiation: in terms of classical theory, the flow of energy at the universal speed of light through free space or through a material medium in the form of the electric and ... [52 Related Articles]
electromagnetic speaker: (from the article "electromechanical transducer") Most loudspeakers are of the electromagnetic, or dynamic, variety, in which a voice coil moves in the gap of a permanent magnet when a time-varying current flows through the coil. ...
electromagnetic spectrum: (from the article "electromagnetic radiation") The brief account of familiar phenomena given above surveyed electromagnetic radiation from small frequencies nu (long wave radios) to exceedingly high values of nu (gamma rays). Going from the nu ...
electromagnetic track brake: (from the article "railroad") ...to prevent wheel slip under heavy braking. On European cars designed for operation at 125 mile/h or more, and on Japanese Shinkansen train-sets, disc braking of wheel sets is supplemented ...
electromagnetic transducer: (from the article "transducer") ...a large group, the major categories of which are differential transformers, Hall-effect magnetic transducers, inductance transducers, induction transducers, and saturable reactors. These operate on electromagnetic principles.
electromagnetic unit of charge: (from the article "electric charge") ...1.60217733 × 10^-19 coulomb. In the centimetre-gram-second system there are two units of electric charge: the electrostatic unit of charge, esu, or statcoulomb; and the electromagnetic unit of charge, emu, ...
electromagnetic wave heating: (from the article "fusion reactor") A plasma needs to be heated to about 100,000,000 K for fusion reactions to take place. Two plasma-heating methods have been highly developed: electromagnetic wave heating and neutral-beam injection heating. ...
electromagnetism: science of charge and of the forces and fields associated with charge. Electricity and magnetism are two aspects of electromagnetism. [17 Related Articles]
electromechanical switching: (from the article "telephone and telephone system") The idea of automatic switching appeared as early as 1879, and the first fully automatic switch to achieve commercial success was invented in 1889 by Almon B. Strowger. The Strowger ...
electromechanical transducer: any type of device that either converts an electrical signal into sound waves (as in a loudspeaker) or converts a sound wave into an electrical signal (as in the microphone). ... [2 Related Articles]
electrometallurgy: (from the article "metallurgy") Extraction is often followed by refining, in which the level of impurities is brought lower or controlled by pyrometallurgical, electrolytic, or chemical means. Pyrometallurgical refining usually consists of the oxidizing ...
electrometer: instrument designed to measure very small voltages and currents. The quadrant, Lindermann, Hoffman, and Wulf electrometers measure electrical potential between charged elements (e.g., plates or fine quartz fibres) within the ... [1 Related Articles]
electromotive force: energy per unit electric charge that is imparted by an energy source, such as an electric generator or a battery. Energy is converted from one form to another in the ... [11 Related Articles]
electromotive series: listing of chemical species (atoms, molecules, and ions) in the order of their tendency to gain or lose electrons (be reduced or oxidized, respectively), expressed in volts and measured with ...
electromyography: the process of graphically recording the electrical activity of muscle. Normal muscle is electrically silent when at rest, but when it is active, as during contraction or stimulation, an electrical ... [3 Related Articles]
electron: lightest stable subatomic particle known. It carries a negative charge, which is considered the basic unit of electric charge. The rest mass of the electron is 9.109 × 10⁻³¹ kg, ... [116 Related Articles]
electron affinity: in chemistry, the amount of energy liberated when an electron is added to a neutral atom to form a negatively charged ion. The electron affinities of atoms are difficult to ... [4 Related Articles]