Search results
Results From The WOW.Com Content Network
The commercially available B&W AC3-30 and B&W DS1.8-30 antennas [6] vary from the above to cover 3–30 MHz using a 90 foot length with an 18 inch spacing of the wires. The balun is a 16:1 ratio, thereby transforming the 50 Ω (ohm) coax to an 800 Ω feed at the antenna. The resistor load is also 800 Ω, non-inductive.
The spin 1/2 Heisenberg model in one dimension may be solved exactly using the Bethe ansatz. [1] In the algebraic formulation, these are related to particular quantum affine algebras and elliptic quantum groups in the XXZ and XYZ cases respectively. [2] Other approaches do so without Bethe ansatz. [3]
The Ising model (or Lenz–Ising model), named after the physicists Ernst Ising and Wilhelm Lenz, is a mathematical model of ferromagnetism in statistical mechanics.The model consists of discrete variables that represent magnetic dipole moments of atomic "spins" that can be in one of two states (+1 or −1).
The Lennard-Jones potential is a simple model that still manages to describe the essential features of interactions between simple atoms and molecules: Two interacting particles repel each other at very close distance, attract each other at moderate distance, and eventually stop interacting at infinite distance, as shown in the Figure.
The reaction field method is used in molecular simulations to simulate the effect of long-range dipole-dipole interactions for simulations with periodic boundary conditions. Around each molecule there is a 'cavity' or sphere within which the Coulomb interactions are treated explicitly.
Magnetic dipole–dipole interaction, also called dipolar coupling, refers to the direct interaction between two magnetic dipoles. Roughly speaking, the magnetic field of a dipole goes as the inverse cube of the distance, and the force of its magnetic field on another dipole goes as the first derivative of the magnetic field. It follows that ...
MAS NMR consists in spinning the sample (usually at a frequency of 1 to 130 kHz) at the magic angle θ m (ca. 54.74°, where cos 2 θ m =1/3) with respect to the direction of the magnetic field. Three main interactions responsible in solid state NMR (dipolar, chemical shift anisotropy, quadrupolar) often lead to very broad and featureless NMR ...
This is exactly the field of a point dipole, exactly the dipole term in the multipole expansion of an arbitrary field, and approximately the field of any dipole-like configuration at large distances. Frames of reference for calculating the forces between two dipoles Force between coaxial cylinder magnets.