Electrical axis deviation

This chart will help you quickly determine the direction of a patient s electrical axis. Observe the deflections of the QRS complexes in leads I and aVp. Lead I indicates whether impulses are moving to the right or left, and lead aVp indicates whether they re moving up or down. Then check the chart to determine whether the patient s axis is normal or has a left, right, or extreme right deviation. 

Axis deviation occurs when electrical activity in the heart moves away from areas of damage or necrosis. 

When the gradient of the electric field does not have axial symmetry another parameter must be introduced to describe the magnitude of the electric field gradients in the solid. This is the asymmetry parameter j , which is a measure of the deviation from axial symmetry (5, 94). In addition, the direction of the principal axis of the electric field gradient tensor must be specified. From single crystal rotation patterns, the values of these parameters may be deduced (94). 

Diffusion couples were encapsulated in quartz ampoules filled with argon. Their annealing was carried out in electric-resistance furnaces, with the temperature deviations from the required value, not exceeding 1°C. After annealing, the couples were cut along the cylindrical axis and... 

Fig. 7.3. The deviation of the optic axis in a cholesteric (hard-twisted chiral nematic, p <, where p is the cholesteric pitch and A is the wavelength of light) when an electric field E is applied perpendicular to the helical axis. The cholesteric geometry allows a fiexoelectric polarization to be induced in the direction of E. The plane containing the director, which is perpendicular to the page in the middle figure and is shown in the lower figure, illustrates the splay-bend distortion and the corresponding polarization that arises. (After Rudquist, inspired by Meyer and Patel.

For most of the crystals mentioned in section 5.3, the periodicity about the c-axis is greater than two-fold (i.e., n > 2). For such so-called uniaxial crystals it is not too difficult to distinguish different types of radiation. Three different spectra need to be compared the axial (for which k c, and hence necessarily Elc and H I c) the transverse n (for which fe L c, c, and hence necessarily H 1 c) and the transverse a (for which k c, Elc, and hence necessarily H c). As Runciman (1958) pointed out, a line coincident in both the axial and a spectra is electric-dipole, while one coincident in both the axial and n spectra is magnetic-dipole or electric-quadrupole. The reader who attempts to verify these assertions soon discovers that the condition n > 2 is crucially important, since the components of D, L -I- 2S and for which q = l must connect a particular lower sublevel to an upper one that is of a different type from that reached by the components for which q = 0. The identifications of D2 of 4f and the levels of the multiplet of 4f referred to in section 5.2 were made by studying the polarizations of the various allowed transitions from sublevel to sublevel. The opportunity for several consistency checks made the J assignments very secure. It turned out that the transitions H4 -> D2 and Fq - D2 are electric-dipole, while Fi-> Dq is magnetic-dipole. Deviations from perfect Russell-Saunders coupling are responsible for the apparent violations of the selection rule AS = 0, which holds for D, L + 2S and... 

If we depart from pure classical electrostatics, things become slightly more complicated. The deviation from spherical symmetry of an atomic nucleus can be described by a nuclear electric quadrupole tensor Q. A natural axis system for this tensor is one where one axis is colinear with the nuclear spin axis. By virtue of the effective cylindrical symmetry of a rapidly spinning deformed nucleus, the components of the quadrupole tensor are determined by a single scalar quantity Q and in addition by the components of the nuclear spin vector i. 

Besides the magnetic dipole moment, nuclei with spin higher than 1/2 also possess an electric quadrupole moment. In a semiclassical picture, the nuclear electric quadrupole moment informs about the deviation of nuclear charge distribution from spherical symmetry. Nuclei with spin 0 or 1/2 are therefore said to be spherical, with zero electric quadrupole moment. On the other hand, if the nuclear spin is higher than 1/2, the nuclei are not spherical, assuming cylindri-cally symmetrical shapes around the symmetry axis defined by the nuclear total angular momentum [17]. Within the subspace [/,m), the nuclear electric quadrupole moment operator is a traceless tensor operator of second rank, with Cartesian components written is terms of the nuclear spin [2] ... 

In case of the low frequency IR laser (u> = 0.057, panel (a)) the deviation of the centroid is not large at all. In the UV laser (w = 0.228, panel (b)), the electronic state is shaked to a large extent. The situation is totally different for the second state as seen in panels (c) and (d). An extremely large fluctuation of the centroid or the induced dipole moment has been realized by the laser. Even the IR laser does an efficient job. The main direction of the dynamical shift of the centroid lies in the a -axis (B-B axis) despite the application of the circularly polarized electric field. The density... 

It is well known that nematic liquid crystals are nonpolar. However, for a certain asymmetrical shape of the molecules, splay or bend deformations of the director field lead to an electrical polarization [87]. This feature is known as the flexoelectric effect. Theoretically, the influence of an electric field on CLCs for the case where the helical axis is oriented parallel to the plane of the sample was first considered by Goossens [88]. Experimentally, the flexoelectric electro-optic effect in CLCs can be observed in conventional sandwich cells with transparent electrodes when the helix axis of the CLC lies parallel to the glass surfaces [89]. In the absence of an electric field, the CLC behaves as a uniaxial material with its optic axis perpendicular to the director and parallel to the helix axis. When an electric field is applied normal to the pitch axis, the helix distorts, as shown in Figure 6.6. Thus, the optical axis is reoriented and the medium becomes biaxial. The deviation direction... 

Tjccy of the apparent viseosity t) on the strain rate A increases from 0.68 at 400 V/mm to 0.93 at 1000 V/mm [75J. This shear thinning phenomenon can be explained qualitatively with the model that the roughly prolate spheroidal droplets are assumed to form in the condensed FR phase [761- The shear flow will rotate the ellipsoidal droplets and thus the long axis will deviate from the direction of the electric field, leading to the weak... 

---