electro-, electr-, electri-

1. A device which accelerates electrons to high energies.
2. A machine that increases the energy levels of electrons in order to produce a beam of highly charged particles.

1. An impurity element that is introduced into a pure semiconductor material to produce holes as charge carriers.
2. An atom or part of a molecule joined by a covalent bond to an electron donor.
3. A molecule or compound that gets electrons during an oxidation-reduction reaction.

A technique for producing images showing the thermal (heat) and elastic variations in the properties of an object: The process of electron acoustic microscopy consists of an electron beam that generates ultrasonic waves in a specimen which are detected by a piezoelectric transducer whose output controls the brightness of a spot sweeping a cathode-ray tube in synchronism with the electron beam.

1. The energy needed to remove an electron from a negative ion in order to form a neutral atom or molecule.
2. The work needed in removing an electron from a negative ion which will restore the neutrality of an atom or molecule.
3. The work needed to remove an electron from a negative ion and move it to infinity.

1. A chain reaction that starts when one free electron collides with one or more orbiting electrons and frees them.

The free electrons then free others in the same manner, etc.

2. The cumulative process in which an electron (or other charged particle) accelerated by a strong electric field collides with and ionizes gas molecules, thereby releasing new electrons which in turn have more collisions, so that the discharge is self-maintained.

1. A stream of electrons emitted from a given source and traveling under the influence of an electric or magnetic field in the same direction and at approximately the same speed.
2. A stream of electrons, or electricity, that is directed towards a receiving object.
3. A narrow stream of electrons moving in the same direction, all having about the same velocity.

The electron beam of the super-microscope has become a basic tool in the research of diseases.

1. The process by which high-energy, high-current electron beams are transported from an accelerator through a medium of high-pressure gas directly to an intended target.
2. A device used in atomic physics to produce highly charged ions by bombarding atoms with a powerful electron beam.
3. The technique of transporting high-energy, high-current electron beams from an accelerator to a target through a region of high-pressure gas by creating a path through the gas where the gas density may be temporarily reduced.

The gas may be ionized; or a current may flow whose magnetic field focuses the electron beam on the target.

Ultrafast computed tomography done with a scanner in which the patient is surrounded by a large circular anode that emits X-rays as the electron beam is guided around it.

1. A device; such as, a klystron, in which the velocity of an electron beam is kept at a constant level in order to produce exceedingly high radio frequencies.
2. Velocity-modulated generator, such as a klystron tube (type of vacuum tube used as an amplifier), used to generate extremely high radio frequencies.

A klystron is an evacuated electron-beam tube in which an initial velocity modulation imparted to electrons in the beam results subsequently in density modulation of the beam. A klystron is used either as an amplifier in the microwave region or as an oscillator.

1. The minimum amount of energy required to extract an electron from an atom or molecule.
2. The energy required to release an electron from its atomic or molecular orbital.

1. In a multimode display-storage tube, a process in which an electron gun is used to erase the image on a cathode-ray tube interface.
2. A method of writing and storing large numbers of information elements electrostatically on the storage tape of a television information storage tube.

A dielectric-coated optical grating on the tape is bombarded with 10-keV electrons to induce momentary conductivity.

This causes electrons to flow fro the dielectric to the metal base of the tape.

Elemental areas on the surface of the tape lose charge in proportion to light from corresponding elemental areas of the image being stored.

1. A device used in gas chromatography, in which carrier gas molecules flowing through the ionization chamber are radiated and low-energy electrons are formed.

Certain compounds entering the chamber have an affinity for these electrons, and this decrease in electrons is recorded for component identification.

2. An extremely sensitive gas chromatography detector that is a modification of the argon ionization detector, with conditions adjusted to favor the formation of negative ions.
3. An item of laboratory equipment used coupled to a gas chromatograph for the detection and quantification of very minute amounts halogenated organic compounds.

1. A process in which an inner shell electron is captured by the nucleus of its own atom.

The mass number is unchanged, but the atomic number is decreased by one and this process is accompanied by the emission of a neutrino.

2. A radioactive decay process in which an atomic nucleus with an excess of protons draws an electron into itself, creating a neutron out of a proton and thus decreasing the atomic number by one.

Often the resulting nucleus is unstable and achieves stability by giving off a gamma ray.

1. A protein; such as, flavoprotein or cytochrome, which can gain and lose electrons in either direction and can transport electrons from one compound to another compound or to oxygen.
2. A molecule that accepts electrons from electron donors and donates them to electron acceptors, creating an energy-producing electron transport chain; such as, that which occurs in respiration and photosynthesis.
3. A molecule associated with membrane-bound proteins that accepts and transfers electrons.
4. Any of various molecules that are capable of accepting one or two electrons from one molecule and donating them to another in the process of electron transport.

As the electrons are transferred from one electron carrier to another carrier, their energy level decreases, and energy is released.

1. The charge of a single electron or the fundamental unit of an electrical charge.
2. The electric charge carried by a single proton, or equivalently, the absolute value of an electric charge carried by a single electron.