Separation In Plane Research Articles

Spatial-mode demultiplexing for enhanced intensity and distance measurement.

Spatial-mode demultiplexing (SPADE) has recently been adopted to measure the separation in the transverse plane between two incoherent point-like sources with sub-wavelength separation. It has been argued that this approach may yield extraordinary performances in the photon-counting regime. Here, we explore SPADE as a tool for precision measurements in the regime of bright, incoherent sources. First we analyze the general problem of estimating the second moments of the source's intensity distribution, for an extended incoherent source of any shape. Our theory predicts a substantial improvement in signal-to-noise ratio (SNR) of SPADE over direct imaging in the sub-wavelength regime. Second, we present an experimental application of SPADE to the case of two point-like, bright sources. We demonstrate the use of this setup for the estimation of the transverse separation and for the estimation of the relative intensity, confirming the expected improvement in SNR.

Impact of temperature and pressure on phase separation in the basal plane of Y0.77Pr0.23Ba2Cu3O7–δ single crystals

Here, we study the impact of high hydrostatic pressure (up to 11 kbar) on the conductivity in the basal ab plane of Y0.77Pr0.23Ba2Cu3O7–δ single crystals. Conversely to YBa2Cu3O7–δ single crystals, it was found that high pressure leads to phase separation in the basal plane of Y0.77Pr0.23Ba2Cu3O7–δ single crystals. The mechanisms of the influence of praseodymium and high hydrostatic pressure on the two-step resistive transition to the superconducting state are discussed.

Effect of high pressure on temperature dependences of the resistivity in the ab-plane of Y0.77Pr0.23Ba2Cu3O7-δ single crystals

In the present work, we investigated the influence of high hydrostatic pressure up to 11 kbar on the conductivity in the basal ab-plane of medium-doped with praseodymium (x≈0.23) single-crystal Y1-xPrxBa2Cu3O7-δ samples. It was determined that, in contrast to the pure YBa2Cu3O7-δsamples with the optimal oxygen content, the application of high pressure leads to the formation of phase separation in the basal plane of Y0.77Pr0.23Ba2Cu3O7-δ single crystals. Possible mechanisms of the effect of Pr doping and high pressure on the two-step resistive transition to the superconducting state are discussed. It was determined that in the normal state, the conductivity is metallic and is limited by phonons scattering (Bloch-Grüneisen regime) and defects. The fluctuation conductivity is considered within the Lorentz-Doniach model. Hydrostatic pressure, accompanied by a decrease in anisotropy, leads to a decrease in the residual and phonon resistances. Debye temperature and coherence length are independent of pressure. The applicability of the McMillan formula in the presence of significant anisotropy is discussed.

Limbic Inducted and Delocalized Effects of Diazole in Carbon Nitride Skeleton for Propelling Photocatalytic Hydrogen Evolution.

Skeleton modification on carbon nitride (g-C3N4) via organic molecules is a recognized effective strategy to improve photocatalytic performance because it can powerfully improve charge separation in the skeleton plane. Herein, a diazole with a unique conjugated structure is bonded on edge of the g-C3N4 skeleton through a moderate polymerization of urea with 4-aminoantipyrine (4AAP). Meanwhile, the Pt nanoparticles selectively deposit on edge of the g-C3N4-4AAP15 nanosheet. It reveals that the robust limbic inducted and delocalized effects of diazole not only facilitate photogenerated electrons aggregation toward skeleton edge to promote in-plane carrier separation but also effectively stabilize and delocalize photogenerated electrons to improve carrier lifetime for propelling the photocatalytic hydrogen evolution (PHE) reaction. Specifically, the PHE rate over optimal g-C3N4-4AAP15 (284.2 μmol h-1) is 10 times that of pure g-C3N4 (27.6 μmol h-1) and the apparent quantum efficiency (AQE) at 420 nm reaches up to 24.2%. Through insights into the functionalized effect of small nitrogenous heterocycles introduced into the skeleton edge of g-C3N4, this work opens a new design thought for exploiting high-efficiency g-C3N4-based photocatalysts for photocatalytic application.

Cervical intervertebral separation caused by trauma on post-mortem computed tomography: Possibility of a diagnosis based on intervertebral gas

ObjectivesGas is a common finding in cervical intervertebral separation. However, intervertebral gas is also found in many decedents without intervertebral separation. Here, we quantified intervertebral gas and examined its value in the diagnosis of cervical intervertebral separation. MethodsWe retrospectively reviewed data from 1118 decedents who underwent post-mortem computed tomography (CT) and autopsy from May 2011 to July 2016 and selected those with cervical intervertebral gas with or without intervertebral separation. These data comprised 56 cervical intervertebral spaces with gas [intervertebral separation in 19 (33.9%)] in 43 subjects [intervertebral separation in 17 (39.5%)]. We categorised the decedents according to gas volume, position, and shape and determined the significance of the differences between the decedents with and without separation. ResultsThe gas volume did not differ significantly between decedents with and without separation (p = 0.063). However, there were significant differences in the gas position between decedents with and without separation. In the sagittal plane: gas was seen in the “centred” position in the ventral-to-dorsal direction in more decedents without separation than in those with separation (p = 0.018). Gas was seen in the ventral-to-dorsal positions in more decedents with separation than in those without separation (p = 0.049). In the cranio-caudal direction, gas in the upper position was more common in decedents with separation than in those without separation in the sagittal plane (p = 0.03).In the coronal plane: gas was seen in the upper position more frequently in decedents with separation in the cranio-caudal direction than in those without separation (p = 0.001). A significant difference in gas shape was observed only in the coronal plane (p = 0.024); irregular gas was associated with decedents without separation. ConclusionGas in the ventral-to-dorsal and upper positions in the sagittal plane and in the upper position in the coronal plane was rather indicative of cervical intervertebral separation. An irregular gas shape in the coronal plane was indicative of degenerative changes.

MaNGA galaxies with off-centered spots of enhanced gas velocity dispersion

Off-centered spots of the enhanced gas velocity dispersion,σ, are revealed in some galaxies from the Mapping Nearby Galaxies at Apache Point Observatory survey (MaNGA). Aiming to clarify the origin of the spots of enhancedσ, we examine the distributions of the surface brightness, the line-of-sight velocity, the oxygen abundance, the gas velocity dispersion, and the Baldwin-Phillips-Terlevich spaxel classification in seven galaxies. We find that the enhancedσspots in six galaxies can be attributed to a (minor) interaction with a satellite. Three galaxies in our sample have a very close satellite (the separation in the sky plane is comparable to the optical radius of the galaxy). The spots of enhancedσin those galaxies are located at the edge of the galaxy close to the satellite. The spots of enhancedσin three other galaxies are related to bright spots in the photometricBband within the galaxy, which can be due to the projection of a satellite in the line of sight of the galaxy. The oxygen abundances in the spots in these three galaxies are reduced. This suggests that the low-metallicity gas from the satellite is mixed with the interstellar medium of the disk, that is, the gas exchange between the galaxy and its satellite takes place. The spectra of the spaxels within a spot are usually H II-region-like, suggesting that the interaction (gas infall) in those galaxies does not result in appreciable shocks. In contrast, the spot of the enhancedσin the galaxy M-8716-12703 is associated with an off-centered active galactic nucleus-like radiation distribution. One can suggest that the spot of the enhancedσin the M-8716-12703 galaxy is different in origin, or that the characteristics of gas infall in this case differs from that in other galaxies.

Comparing power hitting kinematics between skilled male and female cricket batters

ABSTRACT Organismic, task, and environmental constraints are known to differ between skilled male and female cricket batters during power hitting tasks. Despite these influences, the techniques used in such tasks have only been investigated in male cricket batters. This study compared power hitting kinematics between 15 male and 15 female batters ranging from university to international standard. General linear models were used to assess the effect of gender on kinematic parameters describing technique, with height and body mass as covariates. Male batters generated greater maximum bat speeds, ball launch speeds, and ball carry distances than female batters on average. Male batters had greater pelvis-thorax separation in the transverse plane at the commencement of the downswing (β = 1.14; p = 0.030) and extended their lead elbows more during the downswing (β = 1.28; p = 0.008) compared to female batters. The hypothesised effect of gender on the magnitude of wrist uncocking during the downswing was not observed (β = −0.14; p = 0.819). The causes of these differences are likely to be multi-factorial, involving aspects relating to the individual players, their history of training experiences and coaching practices, and the task of power hitting in male or female cricket.

Effect of Hydrogen Corrosion on the Brittle Fracture Resistance of an Oil Line Pipe 530 mm in Diameter Made of 12GSB Ferritic–Pearlitic Steel

The structure, the static tensile properties, the impact toughness, and the fracture mechanisms of the 12GSB pipe steel specimens cut from the defect regions in a pipeline 530 mm in diameter are studied. Hydrogen corrosion is found to affect the anomalous character of the temperature dependences of the impact toughness and the fraction of ductile component in a fracture surface. Sulfur is shown to substantially influence the ductile crack propagation energy in the transverse direction and to weakly influence this energy along the rolling direction. The development of hydrogen corrosion in the pipeline is found to be accompanied by a significant increase in the reduced fraction of intergranular fracture (15.8–35%) in brittle fracture surfaces, and this fraction in the separation plane reaches 50.5%. The relation between the impact toughness of the transverse specimens and the fraction of ductile component in a fracture surface has an anomalous character: this relation has two linear segments, the fracture energies in which differ by an order of magnitude. The segment with a low fracture energy (4.4–16.1 J/cm2) characterizes the action of the sear component of separation in the rolling plane, and the segment with a high fracture energy (38–246 J/cm2), the action of a ductile mode I fracture mechanism. The impact toughness anisotropy coefficient is found to be high, Ka = 2.31.

Optimizing the Solid-State ISOL Technique for Separating Volatile Products of Complete Fusion Reactions

Experiments on measuring the separation efficiency of evaporation residues produced in complete fusion reactions with heavy ions have been performed on the MASHA mass separator. A new design has been developed for a hot catcher based on the use of thin paper from graphite nanotubes and graphene. The catcher is to be used for the synthesis of nuclei at a high intensity of the primary beam to increase the efficiency of separation. A 16-strip silicon detector was used for continuous monitoring during an experiment to measure the mass spectrometer’s efficiency of separation in the intermediate focal plane.

An Upgraded Luminosity Leveling Procedure for the ALICE Experiment

The Large Hadron Collider (LHC) Interface project (LHC_IF) ensures that the A Large Ion Collider Experiment (ALICE) can operate congruently and safely with the LHC in different machine configurations and beam modes. Measurements in proton–proton (pp) collisions are vital for ALICE and serve as a reference to calibrate the Pb ion–Pb ion (Pb–Pb) measurements. However, during the pp operation to limit the event pile up (number of pp collisions per bunch crossing) and ensure a high-quality data sample, the instantaneous luminosity must be limited in ALICE to ${5\times 10^{30} {\text {cm}}^{-2}\,\mathrm {{s}}^{-1}}$ . This is achieved by applying a beam–beam separation in the separation plane up to several beam ${\sigma }$ (beam size unit), which is known as luminosity leveling. Given that the luminosity in a collider is expressed by a well-known formula in terms of parameters such as the beam separation, bunch intensities, number of colliding bunches, and beam size, then it is possible to determine the beam separation if the other parameters are known for both the target luminosity and the measured instantaneous luminosity. From the difference of the two beam separations, different step sizes spanning from 0.5 ${\sigma }$ down to 0.025 ${\sigma }$ are calculated and transmitted to LHC that accordingly steers the beams until the instantaneous luminosity smoothly reaches the target within ± 5%. In this note, the results achieved with the new beam-leveling procedure over almost a year of operation, as well as comparisons with simulations, are presented.

Blind signal separation method and relationship between source separation and source localisation in the TF plane

A method for solving the instantaneous mixtures of the multiple non-stationary wideband signals in the time–frequency (TF) plane is proposed. The blind source separation is performed by calculation of spatial TF distribution matrices, estimation of a separating matrix, estimation of permutation matrices and scaling matrices and TF synthesis. The simulation result shows that the proposed method improves the signal-to-distortion ratio than the preceding methods. Moreover, also the mutual relationship between the source localisation and the source separation is clarified. The source localisation methods using the source separation result and the source separation method using the source localisation result are proposed.

Relationships between technique and bat speed, post-impact ball speed, and carry distance during a range hitting task in cricket

The ability of a batsman to clear the boundary is a major contributor to success in modern cricket. The aim of this study was to identify technique parameters characterising those batsmen able to generate greater bat speeds, ball launch speeds, and carry distances during a range hitting task in cricket. Kinematic data were collected for 20 batsmen ranging from international to club standard, and a series of ball launch, bat-ball impact, and technique parameters were calculated for each trial. A stepwise multiple linear regression analysis found impact location on the bat face in the medio-lateral and longitudinal directions and bat speed at impact to explain 68% of the observed variation in instantaneous post-impact ball speed. A further regression analysis found the X-factor (separation between the pelvis and thorax segments in the transverse plane) at the commencement of the downswing, lead elbow extension, and wrist uncocking during the downswing to explain 78% of the observed variation in maximum bat speed during the downswing. These findings indicate that players and coaches should focus on generating central impacts with the highest possible bat speed. Training and conditioning programmes should be developed to improve the important kinematic parameters shown to generate greater bat speeds, particularly focussing on increased pelvis to upper thorax separation in the transverse plane.

Characteristics of the pulsating jet flow through a dynamic glottal model with a lens-like constriction.

A computational study of the pulsating jet in a squared channel with a dynamic glottal-shaped constriction is presented. It follows the model experiments of Triep and Brücker (J Acoust Soc Am 127(2):1537-1547, 2010) with the cam-driven model that replicates the dynamic glottal motion in the process of human phonation. The boundary conditions are mapped from the model experiment onto the computational model and the three dimensional time resolved velocity and pressure fields are numerically calculated. This study aims to provide more details of flow separation and pressure distribution in the glottal gap and in the supraglottal flow field. Within the glottal gap a 'vena contracta' effect is generated in the mid-sagittal plane. The flow separation in the mid-coronal plane is therefore delayed to larger diffuser angles which leads to an 'axis-switching' effect from mid-sagittal to mid-coronal plane. The location of flow separation in mid-sagittal cross section moves up- and downwards along the vocal folds surface in streamwise direction. The generated jet shear layer forms a chain of coherent vortex structures within each glottal cycle. These vortices cause characteristic velocity and pressure fluctuations in the supraglottal region, that are in the range of 10-30 times of the fundamental frequency.

Characterization of Structural Noise Patterns and Echo Separation in the Time-Frequency Plane for Austenitic Stainless Steels

The aim of this study is to characterize the structural noise for a better flaw detection in heterogeneous materials (steels, weld, composites...) using ultrasonic waves. For this purpose, the continuous wavelet transform is applied to ultrasonic A-scan signals acquired using an ultrasonic non destructive testing (NDT) device. The time-scale representation provided, which highlights the temporal evolution of the spectral content of the A-scan signals, is relevant but can lead to misinterpretation. The problem is to identify if each pattern from the wavelet representation is due to the structural noise or the flaw. To solve this problem, a detection technique based on statistical significance testing in the time-scale plane is used. Information about the structural noise signals is injected into the decision process using an autoregressive model, which seems relevant according to the spectral content of the signal. The approach is tested on experimental signals, obtained by ultrasonic NDT of metallic materials (austenitic stainless steel) then on a weld in this steel and indeed enables to distinguish the components of the signal as flaw echoes, which differ from the structural noise.

Calibration of Biconical Antennas by Vertically Stacking Method

A new way is proposed, and verified by experiment, to measure the free-space antenna factor (F <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">a</sub> ) of biconical antennas over 30 to 300 MHz by the standard antenna method. The antennas were horizontally polarized above a metal ground plane. The usual method of calibrating electromagnetic compatibility antennas is to place two antennas at a given separation in a horizontal plane. Biconical antennas have a uniform H-plane pattern, making it possible to stack the antennas in a vertical plane. The (F <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">a</sub> ) measured with the new method is in close agreement (difference less than 0.6 dB) to that with the vertically polarized method from the FDIS IEC international standard CISPR 16-1-6. Because the antennas are stacked vertically, a smaller ground plane can be used. Because the antennas are horizontally polarized, the vertically routed cable is orthogonal to the antenna so the interaction of cable and antenna is minimized.

Measurement of spatial coherence of electron beams by using a small selected-area aperture

A new method for measuring the spatial coherence of an electron beam in a transmission electron microscope is proposed. In this method, an Airy pattern produced by a circular selected-area (SA) aperture with an effective diameter of several nanometers is analyzed to obtain the degree of coherence as a function of separation in the specimen plane. Using typical TEM illumination conditions, demonstrative measurements were carried out to determine the spatial coherence length, angular size of the electron source and shape of the coherence function. Based on the results, it was shown that the ratio of the spatial coherence length to the beam radius is about 5% for a condenser aperture with a diameter of 100 μm. This means that perfectly coherent illumination exists within the small SA aperture for beam diameters larger than 560 nm. As an example application of these results, the advantage of SA diffraction over nano-beam diffraction in electron diffractive imaging is discussed. The proposed method is unaffected by temporal coherence or geometric aberrations of the lenses. The possibility of carrying out future measurements using SA apertures with conventional sizes is also discussed.

Differences in axial segment reorientation during standing turns predict multiple falls in older adults

BackgroundThe assessment of standing turning performance is proposed to predict fall risk in older adults. This study investigated differences in segmental coordination during a 360° standing turn task between older community-dwelling fallers and non-fallers. MethodsThirty-five older adults age mean (SD) of 71 (5.4) years performed 360° standing turns. Head, trunk and pelvis position relative to the laboratory and each other were recorded using a Vicon motion analysis system. Fall incidence was monitored by monthly questionnaire over the following 12 months and used to identify non-faller, single faller and multiple faller groups. ResultsMultiple fallers were found to have significantly different values, when compared to non-fallers, for pelvis onset (p=0.002); mean angular separation in the transverse plane between the head and trunk (p=0.018); peak angular separation in the transverse plane between the trunk and pelvis (p=0.013); and mean angular separation between the trunk and pelvis (p<0.001). ConclusionsOlder adults who subsequently experience multiple falls show a simplified turning pattern to assist in balance control. This may be a predictor for those at increased risk of falling.

Possible applications of the SiTRD technique in the next generation collider experiments

The Silicon Transition Radiation Detector (SiTRD) combines the excellent space resolution of a silicon tracker with the particle identification capability of a conventional TRD. The detector consists of multiple modules, each composed by a radiator and a tracker plane, separated by a gap and immersed in a magnetic field. This layout allows the separation of the TR photons possibly produced by radiating particles from their trajectories. Provided that the separation in the tracker plane is larger than the granularity of the tracker, the SiTRD can identify radiating particles from non-radiating ones. Moreover, the small amount of material encountered by the particles along their path does not significantly affect the momentum reconstruction performance of the tracker. These features make the SiTRD an attractive option when designing the inner tracker of a collider experiment. We have studied a possible SiTRD layout for the inner tracker of a collider experiment at LHC. The detector parameters have been optimized taking into account the geometry constraints derived from an upgrade proposal of the ATLAS inner tracker. A Monte Carlo simulation has been also developed in which the detector performance has been investigated.

Class Separation Improvements in Pixel Classification Using Colour Injection

This paper presents an improvement in the colour image segmentation in the Hue Saturation (HS) sub-space. The authors propose to inject (add) a colour vector in the Red Green Blue (RGB) space to increase the class separation in the HS plane. The goal of the work is the development of an algorithm to obtain the optimal colour vector for injection that maximizes the separation between the classes in the HS plane. The chromatic Chrominace-1 Chrominance-2 sub-space (of the Luminance Chrominace-1 Chrominance-2 (YC1C2) space) is used to obtain the optimal vector to add. The proposal is applied on each frame of a colour image sequence in real-time. It has been tested in applications with reduced contrast between the colours of the background and the object, and particularly when the size of the object is very small in comparison with the size of the captured scene. Numerous tests have confirmed that this proposal improves the segmentation process, considerably reducing the effects of the variation of the light intensity of the scene. Several tests have been made in skin segmentation in applications for sign language recognition via computer vision, where an accurate segmentation of hands and face is required.

An objective function utilizing complex sparsity for efficient segmentation in multi‐layer oscillatory networks

PurposeThe purpose of this paper is to extend an analysis presented in earlier work which investigated the dynamical behavior of a network of oscillatory units described by the amplitude of and phase of oscillations, and to present an objective function that can be successfully applied to multi‐layer networks.Design/methodology/approachIn this paper, an objective function is presented that can be successfully applied to multi‐layer networks. The behavior of the objective function is explained through its ability to achieve a sparse representation of the inputs in complex‐valued space.FindingsIt is found that if the activity of each network unit is represented by a phasor in the complex plane, then sparsity is achieved when there is maximal phase separation in the complex plane. Increasing the spread of feedback connections is shown to improve segmentation performance significantly but does not affect separation performance. This enables a quantitative approach to characterizing and understanding cortical function.Originality/valueThe formulation of the multi‐layer objective function and the interpretation of its behavior through sparsity in complex space are novel contributions of this paper.