Atom probe samples are shaped to implicitly provide a highly curved electric potential to induce the resultant magnification, as opposed to direct use of lensing, such as via magnetic lenses.

Field evaporation is an effect that can occur when an atom bonded at the surface of a material is in the presence of a sufficiently high and appropriately directed electric field, where the electric field is the differential of electric potential ( voltage ) with respect to distance.

In metallic solids, electric charge flows by means of electrons, from lower to higher electrical potential.

In the early cold cathode vacuum tubes, called Crookes tubes, this was done by using a high electrical potential between the anode and the cathode to ionize the residual gas in the tube ; the ions were accelerated by the electric field and released electrons when they collided with the cathode.

The electrostatic potential at position r due to an electric dipole at the origin is given by:

The electric field from a dipole can be found from the gradient of this potential:

The resulting torque will tend to align the dipole with the applied field, which in the case of an electric dipole, yields a potential energy of

In a similar manner, moving charges being separated from each other in a conductor by a changing electical potential ( such as in an antenna ) produce an electric dipole type electrical field, but this also dies away very quickly with distance.

Notable developments in this century include the work of Georg Ohm, who in 1827 quantified the relationship between the electric current and potential difference in a conductor, Michael Faraday, the discoverer of electromagnetic induction in 1831, and James Clerk Maxwell, who in 1873 published a unified theory of electricity and magnetism in his treatise Electricity and Magnetism.

Electric fields are the cause of several common phenomena, such as electric potential ( such as the voltage of a battery ) and electric current ( such as the flow of electricity through a flashlight ).

* volt ( electric potential )

Charge carriers are separated and physically transported to a position of increased electric potential.

The concept of electric potential is closely linked to that of the electric field.

The electric potential at any point is defined as the energy required to bring a unit test charge from an infinite distance slowly to that point.

This definition of potential, while formal, has little practical application, and a more useful concept is that of electric potential difference, and is the energy required to move a unit charge between two specified points.

An electric field has the special property that it is conservative, which means that the path taken by the test charge is irrelevant: all paths between two specified points expend the same energy, and thus a unique value for potential difference may be stated.

The volt is so strongly identified as the unit of choice for measurement and description of electric potential difference that the term voltage sees greater everyday usage.

The simplest division, and the one most frequently used ( with subdivisions ) in gas and electric rate cases, is a threefold division of the total operating and capital costs into `` customer costs '', `` energy '' or `` volumetric costs '', and `` demand '' or `` capacity '' costs.

In one outstanding example, Whirlpool Corp. found that by switching to urethane foam insulation, they could increase the storage capacity of gas refrigerators to make them competitive with electric models.

Presently they had to give up running the furnace at full capacity and depend on the old coal range in the kitchen, which had never been removed when the new gas range was installed, and the fireplaces and an electric heater in Grandma's room.

Electrophoresis is performed in buffer solutions to reduce pH changes due to the electric field, which is important because the charge of DNA and RNA depends on pH, but running for too long can exhaust the buffering capacity of the solution.

In 1897 second storey wings were added to ‘ The Grandstand ’, as it was known, increasing capacity to 9, 000 and in 1900 it was lit with electric light.

Likewise, due to this high magnetic capacity per weight, neodymium is used in the electric motors of hybrid and electric automobiles, and in the electricity generators of some designs of commercial wind turbines ( only wind turbines with " permanent magnet " generators use neodymium ).

Batteries have previously been of limited use in electric power systems due to their relatively small capacity and high cost.

At the Tientsin Arsenal in 1876, the Chinese developed the capacity to manufacture these " electric torpedoes " on their own.

" It was driven by a 55 horse power electric motor, originally powered by 564 Lalande Chaperon alkaline cells by Coumelin, Desmazures et Baillache with a total capacity of 400 Amphours weighing 11 tons and delivering a maximum current of 166 Amps.

NCL converted the Key System's electric streetcar fleet to diesel buses, tracks were removed from Oakland's streets, and the lower deck of the Bay Bridge was converted to automobile traffic, which reduced the passenger carrying capacity of the bridge.

The American Public Transportation Association ( APTA ) in its Glossary of Transit Terminology defines light rail as: " An electric railway with a ' light volume ' traffic capacity compared to heavy rail.

Coupling the dam's 32 main turbines with two smaller generators ( 50 MW each ) to power the plant itself, the total electric generating capacity of the dam is 22, 500 MW.

The last two of the 20 electric generation units started operations in September 2006 and in March 2007, thus raising the installed capacity to 14 GW and completing the power plant.

Owns and operates 75 plants -- 24 % of U. S. hydropower capacity ( 3 % of the total U. S. electric capacity )

The difference in pH and electric charge ( ignoring differences in buffer capacity ) creates an electrochemical potential that works as if it were similar to a battery or storage unit for energy for the cell ,.

A satellite photo of East Asia at night in 2000 illustrates the limited electric power generating capacity of North Korea in contrast to that of the neighboring countries.

Global geothermal electric capacity.

The East Plant continues to operate at reduced capacity, processing electric arc furnace dust into zinc calcine.

Marcos wanted the immediate construction of roads, bridges and public works, which included 16, 000 kilometers of feeder roads, some 30, 000 lineal meters of permanent bridges, a generator with an electric power capacity of one million kilowatts ( 1, 000, 000 kW ), and water services to eight regions and 38 localities.

For example, the electronic heat capacity of a metal at room temperature seemed to come from 100 times fewer electrons than were in the electric current.

The electric charge-to-mass ratio of a particle can be measured by observing the radius of curling of its cloud-chamber track in a magnetic field.

These ions, under the influence of the electric field, are accelerated into the cathode surface containing the sample, bombarding the sample and causing neutral sample atom ejection through the process known as sputtering.

Atom probes are unlike conventional optical or electron microscopes, in that the magnification effect comes from the magnification provided by a highly curved electric field, rather than by the manipulation of radiation paths.

Preparation is done, often by hand, to manufacture a tip radius sufficient to induce a high electric field, with radii on the order of 100 nm.

The application of the pulsed voltage to the sample allows for individual ions at the sample surface to have their electric field, and hence atomic bonding, temporarily disrupted.

Field ion microscopy techniques were initially construed as a modification of field emission, a technique which allows for a stream of electrons to be emitted from a sharp needle when subjected to a sufficiently high electric field (~ 3-6 V / nm ).

In field ion and atom probe methods, the polarity of the electric field is reversed, with a high positive field applied to the sample.

Therefore the ion speed can be computed with the following equation, which relates kinetic energy to energy gain due to the electric field.

Whilst the magnification of both the field ion and atom probe microscopes is extremely high, the exact magnification is dependant upon conditions specific to the examined specimen, so unlike for conventional electron microscopes, there is often little direct control on magnification, and furthermore, obtained images may have strongly variable magnifications due to fluctuations in the shape of the electric field at the surface.

This corrugation gives rise to strong electric field gradients in the near-tip zone ( on the order of an atomic radii or less from the tip ), which during ionisation deflects ions away from the electric field normal.

Semi-conductor materials are often analysable in atom probe, however sample preparation may be more difficult, and interpretation of results may be more complex, particularly if the semi-conductor contains phases which evaporate at differing electric field strengths.

In 1879, Edwin Herbert Hall working at the Johns Hopkins University discovered the development of a voltage across conductors transverse to an electric current in the conductor and magnetic field perpendicular to the current.