spin system उदाहरण वाक्य
उदाहरण वाक्य
- In the experiment, the spin system is initially perturbed into a non-equilibrium state ( high " H " ), and, as predicted by the " H " theorem the quantity " H " soon decreases to the equilibrium value.
- In the 1970s he showed the equivalence in quantum thermodynamics of, on the one hand, the KMS ( Kubo-Martin-Schwinger ) condition for the characterization of quantum mechanical states in thermodynamic equilibrium with, on the other hand, the variational principle for quantum mechanical spin systems on lattices.
- In the quantum mechanical description of electron and nuclear spin systems that have a limited number of possible states, and therefore a discrete upper limit of energy they can attain, it is possible to obtain a negative temperature, which is numerically indeed less than absolute zero.
- Let us first move away from a gas to an idealized spin system, i . e . a solid whose consituents ( atoms ) store their ( thermal ) energy not by vibrating ( i . e ., no phonons in my model ) but by being excited.
- In the absence of a magnetic field, such a two-spin system would have maximum entropy when half the atoms are in the spin-up state and half are in the spin-down state, and so one would expect to find the system with close to an equal distribution of spins.
- For example, "'AB "'indicates two nuclei which have similar chemical shifts ( ?? similar to or smaller than J ), whereas "'AX "'indicates two which lie further apart on the spectrum ( ?? significantly larger than J ) . "'A 2 B "'would similarly indicate a spin system containing two equivalent nuclei ( A ) and a third, inequivalent one ( B ).
- In the case of a two spin system as described above, we can distinguish two types of pulses : soft or spin-selective pulses, whose frequency range encompasses one of the resonant frequencies only, and therefore affects only that spin; and hard or nonselective pulses whose frequency range is broad enough to contain both resonant frequencies and therefore these pulses couple to both spins.
- The loss of phase coherence in the transverse plane is called transverse or " T " 2 relaxation . " T " 1 is thus associated with the enthalpy of the spin system, or the number of nuclei with parallel versus anti-parallel spin . " T " 2 on the other hand is associated with the entropy of the system, or the number of nuclei in phase.