Buletin Stiintific - UPB - Seria A - numar 2 - 2008
... screened hydrogenic donor in a GaAs-Al0.3Ga0.7As quantum-well wire in the presence of a uniform magnetic field applied parallel to the wire axis. The binding energy is obtained as a function of the wire radius, the field strength and the screening parameter. Our results show that the effects of spat ...
... screened hydrogenic donor in a GaAs-Al0.3Ga0.7As quantum-well wire in the presence of a uniform magnetic field applied parallel to the wire axis. The binding energy is obtained as a function of the wire radius, the field strength and the screening parameter. Our results show that the effects of spat ...
Lecture 35
... The boundary layer is called the depletion layer because it is depleted of carriers. Nearly all of the available carriers have recombined. For Si with nimp = 1016 / cm3, we find d = 20-40 nm. ρ is very large in this depletion layer, since it is the region where the electrons and holes are combined, ...
... The boundary layer is called the depletion layer because it is depleted of carriers. Nearly all of the available carriers have recombined. For Si with nimp = 1016 / cm3, we find d = 20-40 nm. ρ is very large in this depletion layer, since it is the region where the electrons and holes are combined, ...
Electric Current, Current Density, Resistivity and Resistance. A
... Does the current density seem enormous? If our wire had a cross section of thankfully our wire has a much smaller cross section. ...
... Does the current density seem enormous? If our wire had a cross section of thankfully our wire has a much smaller cross section. ...
Magnetic Fields and Magnetic Forces Chapter 27
... discovered in 1820 by Hans Oersted. Current => Magnetic field. Similar experiments by Ampere, Faraday and Henry discovered that a moving magnet near a conducting loop can cause a current in the loop. Ultimately, Maxwell showed that electricity and magnetism are different manifestations of the same p ...
... discovered in 1820 by Hans Oersted. Current => Magnetic field. Similar experiments by Ampere, Faraday and Henry discovered that a moving magnet near a conducting loop can cause a current in the loop. Ultimately, Maxwell showed that electricity and magnetism are different manifestations of the same p ...
Electromagnetic Induction Lab
... Electromagnetic Induction Lab Introduction: In 1831, Michael Faraday - after many experiments - discovered that he could create a current in a wire by moving it through a magnetic field. In principle, he determined that whenever the magnetic field was changing perpendicular to a conductor that a cur ...
... Electromagnetic Induction Lab Introduction: In 1831, Michael Faraday - after many experiments - discovered that he could create a current in a wire by moving it through a magnetic field. In principle, he determined that whenever the magnetic field was changing perpendicular to a conductor that a cur ...
No Slide Title
... – Thumb: I (or v for + charges) – Fingers: where you want to know B – Palm: B ...
... – Thumb: I (or v for + charges) – Fingers: where you want to know B – Palm: B ...
Electric and magnetic phenomena are related and have many
... Send comments to: [email protected] Electric and magnetic phenomena are related and have many practical applications. As a basis for understanding this concept: m. * Students know static electric fields have as their source some arrangement of electric charges. The intent of this Standard (as ...
... Send comments to: [email protected] Electric and magnetic phenomena are related and have many practical applications. As a basis for understanding this concept: m. * Students know static electric fields have as their source some arrangement of electric charges. The intent of this Standard (as ...
Superconductivity
Superconductivity is a phenomenon of exactly zero electrical resistance and expulsion of magnetic fields occurring in certain materials when cooled below a characteristic critical temperature. It was discovered by Dutch physicist Heike Kamerlingh Onnes on April 8, 1911 in Leiden. Like ferromagnetism and atomic spectral lines, superconductivity is a quantum mechanical phenomenon. It is characterized by the Meissner effect, the complete ejection of magnetic field lines from the interior of the superconductor as it transitions into the superconducting state. The occurrence of the Meissner effect indicates that superconductivity cannot be understood simply as the idealization of perfect conductivity in classical physics.The electrical resistivity of a metallic conductor decreases gradually as temperature is lowered. In ordinary conductors, such as copper or silver, this decrease is limited by impurities and other defects. Even near absolute zero, a real sample of a normal conductor shows some resistance. In a superconductor, the resistance drops abruptly to zero when the material is cooled below its critical temperature. An electric current flowing through a loop of superconducting wire can persist indefinitely with no power source.In 1986, it was discovered that some cuprate-perovskite ceramic materials have a critical temperature above 90 K (−183 °C). Such a high transition temperature is theoretically impossible for a conventional superconductor, leading the materials to be termed high-temperature superconductors. Liquid nitrogen boils at 77 K, and superconduction at higher temperatures than this facilitates many experiments and applications that are less practical at lower temperatures.