Overlap Region Research Articles

Functionally graded adhesive joints using magnetic microparticles with a polyurethane adhesive

The present work focuses on using a recently proposed method to create functionally graded adhesive joints using a polyurethane adhesive and iron microparticles. Functionally graded joints were created with the application of a suitable magnetic field in the centre of the overlap region. This field is able to move the iron microparticles and create a tailored particle distribution. The main goal of this work was to create a particle concentration gradient that changes from particle rich in the middle of the overlap to poor in the ends. Consequentially, the stiffness of the resulting composite is made to vary along the bondline. A numerical simulation was performed to determine the optimal distance between the magnet and the adhesive layer as well as the application time of the external magnetic field. In order to assess the influence of the iron particles on the adhesive, different particle amounts were experimentally considered and two particles distributions were evaluated (uniform and graded distributions). The predicted particles trajectories were validated through a study of the single lap joint (SLJ) fracture surfaces, showing that the magnetic particles follow the magnetic field lines towards the middle of the overlap. Also, by observing the same fracture surfaces, the recently proposed method was validated, a non-uniform particle distribution. Finally, SLJs containing 1% of iron microparticles with a graded distribution were found to exhibit the best mechanical performance. Thus, this method has been demonstrated to be a viable technique to enhance the mechanical properties of bonded joints, leading to a more uniform stress distribution along the bondline.

GAMA/XXL: X-ray point sources in low-luminosity galaxies in the GAMA G02/XXL-N field

ABSTRACT Relatively few X-ray sources are known that have low-mass galaxies as hosts. This is an important restriction on studies of active galactic nuclei (AGNs), hence black holes, and of X-ray binaries (XRBs) in low-mass galaxies; addressing it requires very large samples of both galaxies and X-ray sources. Here, we have matched the X-ray point sources found in the XXL-N field of the XXL survey (with an X-ray flux limit of ∼6 × 10−15 erg s−1 cm−2 in the [0.5–2] keV band) to galaxies with redshifts from the Galaxy And Mass Assembly (GAMA) G02 survey field (down to a magnitude limit r = 19.8) in order to search for AGNs and XRBs in GAMA galaxies, particularly those of low optical luminosity or stellar mass (fainter than Mr = −19 or $M_* \lesssim 10^{9.5}\, \mathrm{M}_{\odot }$). Out of a total of 1200 low-mass galaxies in the overlap region, we find a total of 28 potential X-ray source hosts, though this includes possible background contaminants. From a combination of photometry (optical and infrared colours), positional information, and optical spectra, we deduce that most of the ≃20 X-ray sources genuinely in low-mass galaxies are high-mass X-ray binaries in star-forming galaxies. None of the matched sources in a low-mass galaxy has a BPT classification as an AGN, and even ignoring this requirement, none passes both criteria of close match between the X-ray source position and optical galaxy centre (separation ≤3 arcsec) and high [O iii] line luminosity (above 1040.3 erg s−1).

Investigation of the Device Electrical Parameters for Homo and Hetero Junction Based TFETs

This paper presents the analytical approximation of device physics of heterojunction based double gate (DG) Tunnel field effect transistors (TFETs) in terms of potential distribution, electron density and electron barrier tunneling. In order to improve the device performance with respect to ON current (ION), DG TFET with gate-drain overlap is developed. An asymmetric gate oxide is introduced in the gate - drain overlap region and is compared to DG TFET. The device physics and its performance characteristics are studied by using various materials, such as Si, SiGe, InAs and GaSb. The simulated results are validated against the model values. DG TFETs with gate-drain overlap offers higher tunneling probability compared to DG TFETs. Also GaSb/Si based DG TFETs with gate-drain overlap shows good performance improvement by offering higher tunneling probability which in turn offers a higher ION of 1.15 mA/μm.

Density variation effects in α + Pb208 and O16 + Pb208 fusion reactions

We propose a hybrid approach between the sudden model and the adiabatic model to explain the fusion hindrance in heavy-ion fusion reactions at deep subbarrier energies. Due to the strong Pauli blocking effects at the density overlap region, the $\ensuremath{\alpha}$ particle approaching the target $^{208}\mathrm{Pb}$ becomes enlarged and its density distribution gets changed. By introducing energy dependence into this density variation effect, the potentials at different colliding energies are diverse. With the decrease of colliding energies, the significantly enhanced density variation effects make the nuclear potential more attractive and result in a deeper pocket in the inner part. A reasonable description of the experimental fusion cross sections is achieved for the $\ensuremath{\alpha} + ^{208}\mathrm{Pb}$ reaction. On account of highlighting the influence of density variation effects on the fusion process at deep subbarrier energies, we further investigate the density variation effects in the $^{16}\mathrm{O} + ^{208}\mathrm{Pb}$ fusion reaction based on the $\ensuremath{\alpha}$-cluster structures in $^{16}\mathrm{O}$ nuclei. The fusion hindrance at deep subbarrier energies is described well by considering the density variation effects. In addition, an astrophysical $S$ factor between the sudden model and adiabatic model is predicted at the energies below the experimental data.

Sharp boundary formation and invasion between spatially adjacent periodical cicada broods

Periodical cicadas, Magicicada spp., are a useful model system for understanding the population processes that influence range boundaries. Unlike most insects, these species typically exist at very high densities (occasionally >1000/ m2) and have unusually long life-spans (13 or 17 years). They spend most of their lives underground feeding on plant roots. After the underground period, adults emerge from the ground to mate and oviposit over a period of just a few days. Collections of populations that are developmentally synchronized across large areas are known as “broods”. There are usually sharp boundaries between spatially adjacent broods and regions of brood overlap are generally small. The exact mechanism behind this developmental synchronization and the sharp boundary between broods remain unknown: previous studies have focused on the impacts of predator-driven Allee-effects, competition among nymphs, and their impacts on the persistence of off-synchronized emergence events. Here, we present a nonlinear Leslie-type matrix model to additionally consider cicada movement between spatially separated broods, and examine its role in maintaining brood boundaries and within-brood developmental synchrony that is seen in nature. We successfully identify ranges of competition and dispersal that lead to stable coexistence of broods that differ between spatial patches.

A Coarse-to-Fine Strip Mosaicing Model for Airborne Bathymetric LiDAR Data

The airborne light detection and ranging (LiDAR) bathymetry (ALB) system is an extension of the ubiquitous topographic LiDAR mapping system and has been most simply characterized as adding a green laser to the infrared laser of topo systems. Due to the low point cloud density and monotonous objects in the scene, it is difficult to mosaicing the ALB strips. Therefore, the existing airborne laser scanning strip stitching algorithm has poor performance for ALB strips. In this article, a coarse-to-fine strip mosaicing model for ALB is proposed. The framework is fast and efficient and can handle large ALB data. An improved alpha shapes algorithm can fast and accurately determine the overlap region of strip is applied. Due to different data accuracy and spatial characteristics, the water area and land area are processed separately. A weight distribution-based coarse-to-fine registration model is designed for underwater areas. The topological constraint term is added to the nonrigid iterative closest point (ICP) cost function to prevent excessive deformation caused by outliers. The implicit B-spline surface fitting algorithm using the 3L algorithm and the least-squares trend surface fitting algorithm are applied separately to assign weights for overlapping strips to solve the limitation of no control or less control. Moreover, a random sample consensus (RANSAC)-ICP registration model characterized by the normal vector and curvature is constructed for land area. Finally, the comparisons with ICP highlight the superiority of the proposed approach in flexibility and accuracy. The root-mean-square error (RMSE) is 0.12 m and the maximum error is 0.36 m.

Combining Transit and Radial Velocity: A Synthesized Population Model

Abstract We present a framework for estimating exoplanet occurrence rates by synthesizing constraints from radial velocity and transit surveys simultaneously. We employ approximate Bayesian computation and various mass–radius (M–R) relations to explore the population models describing these surveys, both separately and in a joint fit. Using this approach, we fit a planet distribution function of the form , with a break in the power law in mass at M b , to planets orbiting FGK stars with periods days and masses . We find that the M–R relation from Otegi et al. (2020), which lets rocky and volatile-rich populations overlap in mass, allows us to find a model that is consistent with both types of surveys. Our joint fit gives (errors reflect 68.3% credible interval). This is nearly a factor of three higher than the break from transit-only considerations and an M–R relation without such an overlap. The corresponding planet–star mass ratio break may be consistent with microlensing studies ( ). The joint fit also requires that a fraction of planets in the overlap region belong to the rocky population. Our results strongly suggest that future M–R relations should account for a mixture of distinct types of planets in order to describe the observed planet population.

Brain Magnetic Resonance Imaging Characteristics of Anti-Leucine-Rich Glioma-Inactivated 1 Encephalitis and Their Clinical Relevance: A Single-Center Study in China.

Objective: To characterize the magnetic resonance imaging (MRI) features of anti-leucine-rich glioma-inactivated 1 (LGI1) encephalitis and explore their clinical relevance.Methods: Patients with anti-LGI1 encephalitis who underwent MRI at our center were included in this study. Baseline and follow-up MRI characteristics were evaluated, and relationships between lesion location and clinical symptoms were analyzed. The extent of signal abnormalities within the lesion overlap region was measured and correlated with modified Rankin Scale scores and serum antibody titer.Results: Seventy-six patients were enrolled, of which 57 (75%) were classified as MR positive. Brain lesions were located in medial temporal lobe (MTL) (89%) and basal ganglia (BG) (28%). Hippocampus and amygdala were lesion hubs with more than 50% lesion overlap. BG lesions were found in 30% of patients with faciobrachial dystonic seizure (FBDS) and only 7% of patients without FBDS (p = 0.013). Meanwhile, MTL lesions were more commonly observed in patients with memory impairment (70 vs. 0%, p = 0.017). MRI features included hyperintensity and edema at baseline, as well as hypointensity and atrophy at follow-up. Correlations between signal intensity of lesion hubs (including hippocampus and amygdala) and modified Rankin Scale scores were found on T2 (r = 0.414, p < 0.001) and diffusion-weighted imaging (r = 0.456, p < 0.001).Conclusion: MTL and BG are two important structures affected by anti-LGI1 encephalitis, and they are associated with distinctive symptoms. Our study provided evidence from Chinese patients that BG lesions are more commonly observed in patients with FBDS, potentially suggesting BG localization. Furthermore, in addition to supporting diagnosis, MRI has the potential to quantify disease severity.

Light-Responsive Proton Conductor: Record High Gain of Proton Conductivity Achieved by Photoinduced Electron-Transfer Strategy

Light-Responsive Proton Conductor: Record High Gain of Proton Conductivity Achieved by Photoinduced Electron-Transfer Strategy

A comparison of soil texture measurements using mid-infrared spectroscopy (MIRS) and laser diffraction analysis (LDA) in diverse soils

Spectroscopic methods for the determination of soil texture are faster and cheaper than the standard methods, but how do the results compare? To address this question, laser diffraction analysis (LDA) and mid-infrared spectroscopy (MIRS) analysis have been compared to conventional sieve-pipette measurements of texture in diverse European and Kenyan soils. To our knowledge this comparison between LDA and MIRS has not been made previously. It has used soils with a broad range of organic carbon (OC) contents to investigate whether, as in other techniques, clay-OC aggregation affects the estimation of clay with MIRS. The MIRS predictions of clay content were much better than the LDA measurements, but both techniques gave good measurements of sand content. The MIRS over-estimated clay at low clay content and under-estimated at high clay content (calibration set R2 = 0.83). The LDA over-estimated clay by ~ 60% (calibration set R2 = 0.36), indicating that the widely used clay threshold of < 8 µm was too high, and < 4 µm was found to be more accurate. In samples with < 5% OC content, both the LDA and MIRS gave very good clay predictions (R2 = 0.88 and 0.81, respectively). But in predictions of clay content in samples with > 5% OC the LDA under-estimated (R2 = < 0.1) and MIRS over-estimated (R2 = 0.34) clay content. In soils with OC removed, the MIRS prediction of clay content improved, indicating interference between over-lapping spectral regions for organic and mineral constituents. Unlike granulometric measurements of texture such as the LDA, MIRS analysis is not subject to the limitations imposed by the shape and density of particles. It was concluded that in typical agricultural soils with < 5% OC and < 60% clay content, both techniques could be used for cheap, fast and reliable estimates of soil texture.

Investigating relationships between technological variability and ecology in the Middle Gravettian (ca. 32–28 ky cal. BP) in France

The French Middle Gravettian represents an interesting case study for attempting to identify mechanisms behind the typo-technological variability observed in the archaeological record. Associated with the relatively cold and dry environments of GS.5.2 and 5.1, this phase of the Gravettian is characterized by two lithic typo-technical entities (faciès in French): the Noaillian (defined by the presence of Noailles burins) and the Rayssian (identified by the Raysse method of bladelet production).The two faciès have partially overlapping geographic distributions, with the Rayssian having a more northern and restricted geographic extension than the Noaillian. Their chronological relationship, however, is still unclear, and interpretations of their dual presence at many sites within the region of overlap are not yet consensual. Nonetheless, the absence of the Raysse method south of the Garonne River suggests that this valley may have separated two different cultural trajectories for which the Rayssian represents an adaptation to environmental conditions different from those associated with Noaillian assemblages south of the Garonne River. The aim of this study is to test this hypothesis quantitatively using ecological niche modeling (ENM) methods. First, we critically evaluate published data to construct inventories of Noaillian and Rayssian archaeological sites. Next, using ENM methods, we estimate the ecological niches associated with the Middle Gravettian north (Noaillian + Rayssian) and south (Pyrenees Noaillian) of the Garonne River, which are then quantitatively evaluated and compared. Results demonstrate that, despite a relatively large degree of similarity, the niches differ significantly from one another in both geographic and environmental dimensions and that the niche associated with the northern Middle Gravettian is broader than that of the Pyrenees Noaillian. We propose that this pattern reflects different technological, subsistence and mobility strategies linked to the development of the Raysse method in the North, which was likely more advantageous in its environmental contexts than technologies employed by contemporaneous populations in the Pyrenees.

Chemical complexity of the retina addressed by novel phasor analysis of unstained multimodal microscopy

Abstract Unstained multimodal microscopy is capable of non-invasively obtaining chemically specific information with sub-micron spatial resolution; however, spectral overlap makes quantitative analysis difficult. Here, multimodal images that include second-harmonic generation, third-harmonic generation, and two- and three-photon excited fluorescence signals from unstained retinas are analyzed. The composition from each layer of the retina is determined using a novel variation of phasor analysis that is not limited to three components. The super-phasor unmixing (SPU) method is compared with fully constrained linear spectral unmixing. The seven spectroscopic signals in the spectral range 300–690 nm enable the quantitative unmixing of sub-micron pixel spectra even in the presence of noise. The performance of SPU was found to be significantly superior to linear unmixing especially in regions of high spectral overlap. The analysis being presented represents an important step in addressing chemical complexity in congested spaces with applicability to biomedical imaging and unmixing of hyperspectral images.

Plasmon-Enhanced Photovoltaic Characteristics of Black Phosphorus-MoS2 Heterojunction

Van der Waals p-n heterojunctions, consist of atomically thin two-dimensional (2D) layer semiconductors, have opened a promising avenue for the realization of ultrathin and ultralight photovoltaic solar cells. This feature enables them particularly be suitable as the micro/nanoscale solar energy-conversion units integrated in wireless power supply micro/nano-systems. However, solar energy harvest in these heterojunctions is hindered by inherent weak interlayer interaction at such ultrathin thickness. Herein, a novel integrated strategy by embedding metallic plasmonic pentamers optical nano-antenna array (ONAA) onto overlap region of black phosphorus-molybdenum disulfide (BP-MoS <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ) p-n heterojunction is firstly exploited under both a near-infrared laser (λ = 830 nm) and standardized AM1.5G solar irradiation. Results show that profiting from plasmon-induced “hot” electrons and thermal field generating from gigantic near-field enhancement in 15 nm-ultrashort nanogap ONAAs and high intrinsic build-in field in atomically overlap region, this integrated configuration displays enhanced photovoltaic properties. Maximum short-circuits current (I <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">sc</sub> = 0.53 μA) and open circuit voltage (V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">oc</sub> = 0.2 V) had been attained. Additional fill factor of 14% and double power conversion efficiencies amplification are measured via comparison of device without/with ONAAs. These findings strongly demonstrate this reliable enhancement strategy with integration of plasmonic physics into 2D heterojunctions for realizing energy harvesting unit in the wireless power supply micro/nano-systems.

Impact of Cd content on properties of Ni1-xCdxFe2O4 nanoferrites prepared without post-preparation thermal treatment

We report sol–gel auto-combustion synthesis of Ni1-xCdxFe2O4 (0.0–0.72) nano-ferrites (grain-diameter:13.8–28.6 nm) with no thermal-treatment and, its study by x-ray diffraction (XRD), scanning-electron-microscopy-energy-dispersive-x-ray-spectroscopy (SEM-EDS), vibration sample magnetometery, ultraviolet–visible (Uv–Vis) spectroscopic techniques. XRD, EDS confirm formation of spinel phase, with minor-presence of α-Fe2O3 phase. Results show linear increase of lattice parameter; strong compositional dependence of: cationic-distribution (Fe3+ Ni2+ ions more-populated on B-site, Cd2+ distributed on A, B site); inversion-degree; oxygen-parameter; very-similar mean-particle-agglomerate-size; variation of B-O-B A-O-B A-O-A super-exchange-interaction affect magnetic properties. Magnetism is governed by Yafet-Kittel three-sub-lattice model; studied samples remain in the overlap region between single/ multi-domain structures.

A displacement‐based analytical stress solution for various adhesive joint configurations

AbstractThe present work provides a simple and precise thermo‐mechanical model for the prediction of stress distributions in adhesive joints. A displacement‐based derivation is applied, using a general sandwich‐type model for the overlap region. For the adhesive layer a linear displacement approach is proposed, which captures the variation of the shear stresses in the through‐thickness direction. The model covers various joint configurations with linear‐elastic material behavior under different load cases.

Gate-Normal Negative Capacitance Tunnel Field-Effect Transistor (TFET) With Channel Doping Engineering

In this work, a negative capacitance tunnel FET (NCTFET) with the tunneling current in the normal direction to the gate is proposed with channel doping engineering and its electrical characteristics are investigated using TCAD simulations with calibrated model parameters. The new NCTFET has a p <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> -doping (for n-type operations) in the channel overlap region, which plays a role to suppress the corner (source edge) band-to-band tunneling (BTBT) that degrades the on/off transition. By optimizing the doping concentration of the channel overlap region (N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">CH,OV</sub> ), the on-current gets ~3.5 times enhanced and the averaged subthreshold swing (SS <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">AVE</sub> ) becomes reduced from 82.5 mV/dec to 43.9 mV/dec. Furthermore, the effects of epi-channel thickness (T <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">CH</sub> ) and source overlap length (L <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">S,OV</sub> ) variations are analyzed by simulating 2D contour BTBT generation rates and electron densities. With the optimized device parameters (4 nm T <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">CH</sub> and 35 nm L <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">S,OV</sub> ), the on-current is additionally ~1.6 times improved without the SS and the ambipolar current degradations.

Deep-learning based multi-modal retinal image registration for the longitudinal analysis of patients with age-related macular degeneration.

This work reports a deep-learning based registration algorithm that aligns multi-modal retinal images collected from longitudinal clinical studies to achieve accuracy and robustness required for analysis of structural changes in large-scale clinical data. Deep-learning networks that mirror the architecture of conventional feature-point-based registration were evaluated with different networks that solved for registration affine parameters, image patch displacements, and patch displacements within the region of overlap. The ground truth images for deep learning-based approaches were derived from successful conventional feature-based registration. Cross-sectional and longitudinal affine registrations were performed across color fundus photography (CFP), fundus autofluorescence (FAF), and infrared reflectance (IR) image modalities. For mono-modality longitudinal registration, the conventional feature-based registration method achieved mean errors in the range of 39-53 µm (depending on the modality) whereas the deep learning method with region overlap prediction exhibited mean errors in the range 54-59 µm. For cross-sectional multi-modality registration, the conventional method exhibited gross failures with large errors in more than 50% of the cases while the proposed deep-learning method achieved robust performance with no gross failures and mean errors in the range 66-69 µm. Thus, the deep learning-based method achieved superior overall performance across all modalities. The accuracy and robustness reported in this work provide important advances that will facilitate clinical research and enable a detailed study of the progression of retinal diseases such as age-related macular degeneration.

Tomographic imaging using multi-simultaneous measurements (TIMes) for flame emission reconstructions.

The method of tomographic imaging using multi-simultaneous measurements (TIMes) for flame emission reconstructions is presented. Measurements of the peak natural CH* chemiluminescence in the flame and luminescence from different vaporised alkali metal salts that were seeded in a multi-annulus burner were used. An array of 29 CCD cameras around the Cambridge-Sandia burner was deployed, with 3 sets of cameras each measuring a different colour channel using bandpass optical filters. The three-dimensional instantaneous and time-averaged fields of the individual measured channels were reconstructed and superimposed for two new operating conditions, with differing cold flow Reynolds numbers. The contour of the reconstructed flame front followed the interface between the burnt side of the flame, where the alkali salt luminescence appears, and the cold gas region. The increased mixing between different reconstructed channels in the downstream direction that is promoted by the higher levels of turbulence in the larger Reynolds number case was clearly demonstrated. The TIMes method enabled combustion zones originating from different streams and the flame front to be distinguished and their overlap regions to be identified, in the entire volume.

Grain growth prediction in selective electron beam melting of Ti-6Al-4V with a cellular automaton method

An integrated modeling framework coupling the discrete element method for powder spreading, finite volume method for powder bed melting, and an extended cellular automaton method for grain structure evolution during solidification is proposed. In this framework, the initial grain structure of both the substrate and metal powders can be taken into account and used to capture epitaxial and competitive grain growth. The framework is used to provide an in-depth understanding of microstructure development in Ti-6Al-4V during the selective electron beam melting process. The complex process of grain growth during deposition of multiple tracks and multiple layers is modeled through an analysis restarting scheme. The epitaxial growth of grains from pre-existing grains, in particular the grains of partially melted powders, is reproduced. The mechanism of microstructure development within the overlap region of consecutive tracks and layers for various scan strategies is revealed. The simulation results are in qualitative agreement with experimental observation in the literature. The proposed modeling framework is a powerful tool to guide optimal process parameters that lead to designed, site-specific microstructure control and therefore to tailored mechanical properties of parts fabricated by the powder bed fusion additive manufacturing process.

Two-Pion Intensity Interferometry in Au+Au @ 1.23A GeV

High-statistics π−π− HBT data for non-central Au +Au collisions at 1.23A GeV, measured with HADES at SIS18/GSI, are presented. The three-dimensional emission source is studied in dependence on pair transverse momentum and centrality. A tilt of the source relative to the beam axis is observed. The spatial extension and the tilt magnitude of the source decrease with transverse momentum. The spatial extension decreases and the tilt magnitude increases going from central to peripheral collisions. The derived eccentricity perpendicular to the beam axis fits well to the initial nucleonic overlap region at high transverse momentum, while the eccentricities from lower pair transverse momentum pions are found to decrease as the pair momentum is reduced.