Transverse plane

About: Transverse plane is a research topic. Over the lifetime, 17069 publications have been published within this topic receiving 194059 citations. The topic is also known as: axial plane.

Three-dimensionality of organized structures in a plane turbulent wake

Abstract: This paper describes a quantitative study of the three-dimensional nature of organized motions in a turbulent plane wake. Coherent structures are detected from the instantaneous, spatially phase-correlated vorticity field using certain criteria based on size, strength and geometry of vortical structures. With several combinations of X-wire rakes, vorticity distributions in the spanwise and transverse planes are measured in the intermediate region (10d [les ] x [les ] 40d) of the plane turbulent wake of a circular cylinder at a Reynolds number of 13000 based on the cylinder diameter d. Spatial correlations of smoothed vorticity signals as well as phase-aligned ensemble-averaged vorticity maps over structure cross-sections yield a quantitative measure of the spatial coherence and geometry of organized structures in the fully turbulent field. The data demonstrate that the organized structures in the nominally two-dimensional wake exhibit significant three-dimensionality even in the near field. Using instantaneous velocity and vorticity maps as well as correlations of vorticity distributions in different planes, some topological features of the dominant coherent structures in a plane wake are inferred.

Patient positioning indication arrangement for a computed tomography system

Abstract: A computed tomography system has an arrangement for indicating the staged position of a patient in relation to the location of a first scan by the system. The arrangement includes at least one energy beam source, such as a laser, which projects a visible pattern on the surface of the patient. The pattern corresponds to the central alignment of the system and to the location of the first scan of the system when a patient-supporting table is subsequently translated into a gantry of the system for x-ray examination. The pattern includes a central longitudinal line indicating a central longitudinal plane of the area to be scanned, and a transverse line indicating the location of the transverse plane of the first scan. The energy beam source of the arrangement is adjustable to project an angled line which corresponds to a tilted gantry or a tilted patient, or a tilted supporting table to indicate the location of the transverse plane of the first scan of the system. The patient is aligned and located in agreement to the projected patterns to thereby properly position the patient for the subsequent desired first scan by the system.

Magnetic Quantum Tunneling in the Single-Molecule Magnet Mn12-Acetate

Abstract: The symmetry of magnetic quantum tunneling (MQT) in the single molecule magnet Mn2-acetate has been determined by sensitive low-temperature magnetic measurements in the pure quantum tunneling regime and high frequency EPR spectroscopy in the presence of large transverse magnetic fields. The combined data set definitely establishes the transverse anisotropy terms responsible for the low temperature quantum dynamics. MQT is due to a disorder induced locally varying quadratic transverse anisotropy associated with rhombic distortions in the molecular environment (2nd order in the spin-operators). This is superimposed on a 4th order transverse magnetic anisotropy consistent with the global (average) S4 molecule site symmetry. These forms of the transverse anisotropy are incommensurate, leading to a complex interplay between local and global symmetries, the consequences of which are analyzed in detail. The resulting model explains: (1) the observation of a twofold symmetry of MQT as a function of the angle of the transverse magnetic field when a subset of molecules in a single crystal are studied; (2) the non-monotonic dependence of the tunneling probability on the magnitude of the transverse magnetic field, which is ascribed to an interference (Berry phase)effect; and (3) the angular dependence of EPR absorption peaks, including the fine structure in the peaks, among many other phenomena. This work also establishes the magnitude of the 2nd and 4th order transverse anisotropy terms for Mn12-acetate single crystals and the angle between the hard magnetic anisotropy axes of these terms. EPR as a function of the angle of the field with respect to the easy axes (close to the hard-medium plane) confirms that there are discrete tilts of the molecular magnetic easy axis from the global (average) easy axis of a crystal, also associated with solvent disorder. The latter observation provides a very plausible explanation for the lack of MQT selection rules, which has been a puzzle for many years.

A Triple-Band Ultrathin Metamaterial Absorber With Wide-Angle and Polarization Stability

Abstract: This letter presents a triple-band compact and efficient ultrathin metamaterial absorber with wide-angle and polarization stability. The compact single unit cell includes a metallic background plane, four groups of dipoles lying around a metallic ring connected by four groups of pins, and only 1-mm low-cost dielectric layer. In addition, the main parameters of the designed absorber are investigated and optimized to show that each of three absorption frequency points can be effectively separately adapted, respectively. The simulation results demonstrate that this absorber has good absorption rates and polarization-insensitive characteristic over wide angles of incident waves for both transverse electric (TE) and transverse magnetic (TM) in three frequency bands. The waveguide measurement method is utilized to test the simulated results of three good absorption peaks.