X-rays are the best band for studying black holes as the radiations emitted by the black hole is X-rays so we can expect the presence of a black hole anywhere in the Universe.
The principle of semiconductor laser is very different from CO2 and Nd:YAG lasers. It is based on "Recombination Radiation" The semiconductor materials have valence band V and conduction band C, the energy level of conduction band is Eg (Eg>0) higher than that of valence band. To make things simple, we start our analysis supposing the temperature to be 0 K. It can be proved that the conclusions we draw under 0 K applies to normal temperatures. Under this assumption for nondegenerate semiconductor, initially the conduction band is completely empty and the valence band is completely filled. Now we excite some electrons from valence band to conduction band, after about 1 ps, electrons in the conduction band drop to the lowest unoccupied levels of this band, we name the upper boundary of the electron energy levels in the conduction band the quasi-Fermi level Efc. Meanwhile holes appear in the valence band and electrons near the top of the valence band drop to the lowest energy levels of the unoccupied valence energy levels, leave on the top of the valence band an empty part. We call the new upper boundary energy level of the valence band quasi-Fermi level Efv. When electrons in the conduction band run into the valence band, they will combine with the holes, in the same time they emit photons. This is the recombination radiation. Our task is to make this recombination radiation to lase
Chuck berry
Black Box later renamed Blackbox
The band Sid (シド) sings this song
pie band
All materials radiate heat equivalent to their temperature above absolute zero.This heat is called "black body" radiation. When the peak of the "black body" radiation from a material is in the infrared band we perceive it as heat, but the radiation is always radiant heat regardless of whether it peak is in the radio band, infrared band, visible band, ultraviolet band, x-ray band, etc.
Well, they aren't always black. Heatsinks that depend mostly on convection or forced air to dispose of waste heat can be any color.However a heatsink that depends in large part on radiation to dispose of waste heat should be black. This is because the ideal emitter/absorber of radiation is a blackbody. A blackbody emits an ideal continuous spectrum of electromagnetic radiation with a peak at the high end of the band and no missing frequencies in that band. If the color is not black there are missing frequencies and the radiation is not the most efficient it could be.
hoes are vacancies left by the electron in the valence band. hence there cannot be holes in the conduction band
A bandshape is a shape of a band of electromagnetic radiation.
The principle of semiconductor laser is very different from CO2 and Nd:YAG lasers. It is based on "Recombination Radiation" The semiconductor materials have valence band V and conduction band C, the energy level of conduction band is Eg (Eg>0) higher than that of valence band. To make things simple, we start our analysis supposing the temperature to be 0 K. It can be proved that the conclusions we draw under 0 K applies to normal temperatures. Under this assumption for nondegenerate semiconductor, initially the conduction band is completely empty and the valence band is completely filled. Now we excite some electrons from valence band to conduction band, after about 1 ps, electrons in the conduction band drop to the lowest unoccupied levels of this band, we name the upper boundary of the electron energy levels in the conduction band the quasi-Fermi level Efc. Meanwhile holes appear in the valence band and electrons near the top of the valence band drop to the lowest energy levels of the unoccupied valence energy levels, leave on the top of the valence band an empty part. We call the new upper boundary energy level of the valence band quasi-Fermi level Efv. When electrons in the conduction band run into the valence band, they will combine with the holes, in the same time they emit photons. This is the recombination radiation. Our task is to make this recombination radiation to lase
Electromagnetic Radiation
Black Sunshine - band - was created in 2009.
Black Ice - band - was created in 1999.
Black Cobra - band - was created in 2002.
Black Face - band - was created in 2011.
Pitch Black - band - was created in 1997.
Black Widow - band - was created in 1969.