![ay221 - CCEA](http://s1.studyres.com/store/data/016432776_1-cd4fe5f818acf519c84764e89bad06bf-300x300.png)
ay221 - CCEA
... Figures in brackets printed down the right-hand side of pages indicate the marks awarded to each question. Your attention is drawn to the Data and Formulae Sheet which is inside this question paper. You may use an electronic calculator. Question 8 contributes to the synoptic assessment required of t ...
... Figures in brackets printed down the right-hand side of pages indicate the marks awarded to each question. Your attention is drawn to the Data and Formulae Sheet which is inside this question paper. You may use an electronic calculator. Question 8 contributes to the synoptic assessment required of t ...
Störmer
... atomic-layer growth process, silicon impurities are introduced into the AlGaAs material at a distance of about 0.1 m from the interface. Each silicon impurity has one more outer-shell electron than the gallium atom, which it replaces in the solid. It easily loses this additional electron, which wan ...
... atomic-layer growth process, silicon impurities are introduced into the AlGaAs material at a distance of about 0.1 m from the interface. Each silicon impurity has one more outer-shell electron than the gallium atom, which it replaces in the solid. It easily loses this additional electron, which wan ...
Universidad de Cantabria ON LIGHT SCATTERING BY NANOPARTICLES WITH CONVENTIONAL AND NON-CONVENTIONAL
... more precisely on systems at the nanometer scale. Mie theory, as described above, is valid for all particle sizes and incident wavelengths. However, for very small particles compared to wavelength, some approximations can be applied, which simplify the expressions given in the previous section. Sinc ...
... more precisely on systems at the nanometer scale. Mie theory, as described above, is valid for all particle sizes and incident wavelengths. However, for very small particles compared to wavelength, some approximations can be applied, which simplify the expressions given in the previous section. Sinc ...
Preliminary Evidence of Field Induced Rhenium
... adsorbed in surfaces takes place. The redistribution affects both internal and surface bonds of the molecule. The redistribution of electrons can increase or decrease a bonds’ strength depending if the bonding or antibonding orbitals in the molecule are more affected.2 This phenomenon is called fiel ...
... adsorbed in surfaces takes place. The redistribution affects both internal and surface bonds of the molecule. The redistribution of electrons can increase or decrease a bonds’ strength depending if the bonding or antibonding orbitals in the molecule are more affected.2 This phenomenon is called fiel ...
Superconductivity
![](https://commons.wikimedia.org/wiki/Special:FilePath/Meissner_effect_p1390048.jpg?width=300)
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.