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The helicity of a particle is positive (" right-handed") if the direction of its spin is the same as the direction of its motion and negative ("left-handed") if opposite. Helicity is conserved. [1] That is, the helicity commutes with the Hamiltonian, and thus, in the absence of external forces, is time-invariant. It is also rotationally ...
Magnetic helicity is a gauge-dependent quantity, because can be redefined by adding a gradient to it (gauge choosing).However, for perfectly conducting boundaries or periodic systems without a net magnetic flux, the magnetic helicity contained in the whole domain is gauge invariant, [15] that is, independent of the gauge choice.
Helicity may refer to: Helicity (fluid mechanics) , the extent to which corkscrew-like motion occurs Helicity (particle physics) , the projection of the spin onto the direction of momentum
It describes the rate of change of vorticity of the moving fluid particle. This change can be attributed to unsteadiness in the flow ( ∂ω / ∂t , the unsteady term) or due to the motion of the fluid particle as it moves from one point to another ((u ∙ ∇)ω, the convection term).
In fluid dynamics, the lift per unit span (L') acting on a body in a two-dimensional flow field is directly proportional to the circulation, i.e. it can be expressed as the product of the circulation Γ about the body, the fluid density , and the speed of the body relative to the free-stream : ′ =
In statistical mechanics, the Zimm–Bragg model is a helix-coil transition model that describes helix-coil transitions of macromolecules, usually polymer chains. Most models provide a reasonable approximation of the fractional helicity of a given polypeptide; the Zimm–Bragg model differs by incorporating the ease of propagation (self-replication) with respect to nucleation.
At equilibrium, the rate of net energy production in the system must equal the rate of energy loss due to frictional dissipation at the surface, i.e. W i n = W o u t {\displaystyle W_{in}=W_{out}} The rate of energy loss per unit surface area from surface friction, W o u t {\displaystyle W_{out}} , is given by
Online Mie solution calculator is available, with documentation in German and English. Online Mie scattering calculator produces beautiful graphs over a range of parameters. phpMie Online Mie scattering calculator written on PHP. Mie resonance mediated light diffusion and random lasing. Mie solution for spherical particles.