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This process is known as stimulated emission. In a group of such atoms, if the number of atoms in the excited state is given by N 2, the rate at which stimulated emission occurs is given by = = where the proportionality constant B 21 is known as the Einstein B coefficient for that particular transition, and ρ(ν) is the radiation density of ...
Schematic diagram of atomic stimulated emission. Stimulated emission (also known as induced emission) is the process by which an electron is induced to jump from a higher energy level to a lower one by the presence of electromagnetic radiation at (or near) the frequency of the transition. From the thermodynamic viewpoint, this process must be ...
The decay scheme of a radioactive substance is a graphical presentation of all the transitions occurring in a decay, and of their relationships. Examples are shown below. It is useful to think of the decay scheme as placed in a coordinate system, where the vertical axis is energy, increasing from bottom to top, and the horizontal axis is the proton number, increasing from left to right.
The link between the Lewis blood group and secretion of the ABO blood group antigens was possibly the first example of multiple effects of a human gene: [1] the same enzyme (fucosyltransferase2) which converts the Le-a antigen to Le-b is also responsible for the presence of soluble A, B and H antigens in bodily fluids.
Stimulated emission depletion (STED) microscopy is one of the techniques that make up super-resolution microscopy. It creates super-resolution images by the selective deactivation of fluorophores , minimizing the area of illumination at the focal point, and thus enhancing the achievable resolution for a given system. [ 1 ]
This technique primarily utilizes fluorophores to visualize the location of the antibodies, while others provoke a color change in the environment containing the antigen of interest or make use of a radioactive label. Immunofluorescent techniques that utilized labelled antibodies was conceptualized in the 1940s by Albert H. Coons. [2] [6] [7]
[2] [3] [4] The Kramers–Heisenberg formula was an important achievement when it was published, explaining the notion of "negative absorption" ( stimulated emission ), the Thomas–Reiche–Kuhn sum rule , and inelastic scattering — where the energy of the scattered photon may be larger or smaller than that of the incident photon — thereby ...
A complete blood type would describe each of the 45 blood groups, and an individual's blood type is one of many possible combinations of blood-group antigens. [3] Almost always, an individual has the same blood group for life, but very rarely an individual's blood type changes through addition or suppression of an antigen in infection, malignancy, or autoimmune disease.