Field static

Cells or other small particles may be observed to spin in an electric field that is either static, oscillatory, or rotating in direction. The spinning of more or less spherical bodies in a static field has been known for some time. The theory and confirming experiments for that type due to surface charge deposition by ambipolar (bidirectional) current have been given. 

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The dielectric constant (permittivity) tabulated is the relative dielectric constant, which is the ratio of the actual electric displacement to the electric field strength when an external field is applied to the substance, which is the ratio of the actual dielectric constant to the dielectric constant of a vacuum. The table gives the static dielectric constant e, measured in static fields or at relatively low frequencies where no relaxation effects occur. 

Static fields mass spectrometer. A mass spectrometer that can separate ion beams with fields that do not vary with time. These fields are generally electrostatic or magnetic. 

Nuclear Magnetic Resonance. The iateraction of a nucleus with Bq is usually described usiag vector notation and models as ia Figure 2 where the bulk magnetization, Af, and the static field Bq are initially parallel to A radio frequency pulse is appHed ia the xy plane for a duration of t p.s,... 

Rotating armature These have a rotating armature and a static field excitation system. The output from the armature is taken through the sliprings. 

Molecules respond to frequency-dependent fields in a quite different way than to static fields, and some care has to be exercised when comparing the results of theory and experiment. 

The first step in our quantum-mechanical calculation is the construction of an appropriate molecular Hamiltonian. For a weak constant static field E we have... 

Derivation of this equation is actually far from straightforward. In electromagnetism, we describe static fields by the electric field E and the magnetic induction B. For our purposes, we need to enquire about the potentials rather than the fields, and these are defined by... 

Electrostatic devices These devices provide a static field within the water via the production of a very high localized voltage (but low current). It is claimed that this field physically affects the dissolved mineral ions and inhibits the precipitation of scale. 

The resonance splitting of intramolecular modes in the crystalline state is often called Davydov splitting or factor group splitting . In contrast to the static field effects of the crystal, this splitting is due to the dynamical interaction of the constituents in the primitive cell... 

Schmelcher PS, Cederbaum LS (1996) Two Interacting Charged Particles in Strong Static Fields A Variety of Two-Body Phenomena. 86 27-62 Schmid G (1985) Developments in Transition Metal Cluster Chemistry. The Way to Large Clusters. 62 51-85... 

The deuterium line of the deuterated solvent is used for this purpose, and, as stated earlier, the intensity of this lock signal is also employed to monitor the shimming process. The deuterium lock prevents any change in the static field or radiofrequency by maintaining a constant ratio between the two. This is achieved via a lock feedback loop (Fig. 1.10), which keeps a constant frequency of the deuterium signal. The deuterium line has a dispersion-mode shape i.e., its amplitude is zero at resonance (at its center), but it is positive and negative on either side (Fig. 1.11). If the receiver reference phase is adjusted correcdy, then the signal will be exactly on resonance. If, however, the field drifts in either direction, the detector will... 

The deuterium lock prevents changes in the static field (Bq) and radiofrequency (B,) by maintaining a constant ratio between the two. It therefore ensures long-term stability of the magnetic field. If the lock is not applied, a drastic deterioration in the shape of the NMR lines is expected, due to magnetic and radioffequency inhomogeneities, (a) With deuterium lock... 

The symmetry-breaking of the HF function occurs when the resonance between the two localized VB form A+...A and A...A+ is weaker than the electronic relaxation which one obtains by optimizing the core function in a strong static field instead of keeping it in a weak symmetrical field. If one considers for instance binding MOs between A and A they do not feel any field in the SA case and a strong one in the SB solution. The orbitals around A concentrate, those around A become more diffuse than the compromise orbitals of A+ 2 and these optimisations lower the energy of the A. A form. As a... 

The quantity of interest is the precession of the components perpendicular to B0 that are measured in the experiment by induced voltage in the coil, which is subsequently amplified and demodulated. We can write them either as individual components Mx, M, or by a vector M+, which combines both of them. In the static field, the precession about B0 occurs with the Larmor frequency w0 = /B0. If we neglect those processes which dampen the amplitude of the rotating transverse magnetization as precession proceeds, this already describes the frequency that we pick up with our receiver coil, and it is the third and perhaps the most important of our three fundamental equations of NMR ... 

In the schematic the detector coil (hatched boxes) and its associated field lines are shown (dotted) and are seen to be always orthogonal to the permanent magnet field lines (solid). The magnitude of the static field is constant in the horizontal plane (thick black line). A stepper motor and gear-drives for raising the whole assembly relative to the external surface are visible in the photograph. 

The inducing field responsible for the energy of the induced dipoles, Umd, has contributions from three terms the permanent or static field, Ustat, the induced dipole-induced dipole interaction, Udip, and the polarization energy, Upou... 

It is noteworthy that the induced energy is the dot product of the induced dipole and the static field and not the total field. The interpretation of Eq. (9-11) is that a static field is required to originate induced dipoles. 

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