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The macroscopic energy equation for infinitesimal volume used in heat transfer analysis is [6] = +, ˙, where q is heat flux vector, −ρc p (∂T/∂t) is temporal change of internal energy (ρ is density, c p is specific heat capacity at constant pressure, T is temperature and t is time), and ˙ is the energy conversion to and from thermal ...
Jablonski diagram of FRET with typical timescales indicated. The black dashed line indicates a virtual photon.. Förster resonance energy transfer (FRET), fluorescence resonance energy transfer, resonance energy transfer (RET) or electronic energy transfer (EET) is a mechanism describing energy transfer between two light-sensitive molecules (chromophores). [1]
Increase of amplitude as damping decreases and frequency approaches resonant frequency of a driven damped simple harmonic oscillator. [1] [2]Resonance is a phenomenon that occurs when an object or system is subjected to an external force or vibration that matches its natural frequency.
According to this theory, energy emitted by a radiator is not continuous but is in the form of quanta. Planck noted that energy was emitted in quantas of frequency of vibration similarly to the wave theory. [18] The energy E an electromagnetic wave in vacuum is found by the expression E = hf, where h is the Planck constant and f is its frequency.
The transfer of energy from the low wavenumbers to the high wavenumbers is the energy cascade. This transfer brings turbulence kinetic energy from the large scales to the small scales, at which viscous friction dissipates it. In the intermediate range of scales, the so-called inertial subrange, Kolmogorov's hypotheses lead to the following ...
Energy flux, the rate of transfer of energy through a unit area (J·m −2 ·s −1). The radiative flux and heat flux are specific cases of energy flux. Particle flux, the rate of transfer of particles through a unit area ([number of particles] m −2 ·s −1) These fluxes are vectors at each point in space, and have a definite magnitude and ...
where: is the rate of change of the energy density in the volume. ∇•S is the energy flow out of the volume, given by the divergence of the Poynting vector S. J•E is the rate at which the fields do work on charges in the volume (J is the current density corresponding to the motion of charge, E is the electric field, and • is the dot product).
The Dexter energy transfer rate, , is indicated by the formula: = ′ [] where is the separation of the donor from the acceptor, is the sum of the Van der Waals radii of the donor and the acceptor, and ′ is the normalized spectral overlap integral, where normalized means that both emission intensity and extinction coefficient have been adjusted to unit area.