Layer Boundary Research Articles

Generating Multi-Depth 3D Holograms Using a Fully Convolutional Neural Network.

Efficiently generating 3D holograms is one of the most challenging research topics in the field of holography. This work introduces a method for generating multi-depth phase-only holograms using a fully convolutional neural network (FCN). The method primarily involves a forward-backward-diffraction framework to compute multi-depth diffraction fields, along with a layer-by-layer replacement method (L2RM) to handle occlusion relationships. The diffraction fields computed by the former are fed into the carefully designed FCN, which leverages its powerful non-linear fitting capability to generate multi-depth holograms of 3D scenes. The latter can smooth the boundaries of different layers in scene reconstruction by complementing information of occluded objects, thus enhancing the reconstruction quality of holograms. The proposed method can generate a multi-depth 3D hologram with a PSNR of 31.8dB in just 90ms for a resolution of 2160×3840 on the NVIDIA Tesla A100 40G tensor core GPU. Additionally, numerical and experimental results indicate that the generated holograms accurately reconstruct clear 3D scenes with correct occlusion relationships and provide excellent depth focusing.

Contact area analysis of an asphalt-concrete boundary layer with X-ray computed tomography imaging

This study focusses on the bond between asphalt and concrete. The bond is a decisive factor for the transfer of traffic loads. A lack of bond between the layers can quickly reduce the load-bearing behavior and thus lead to pavement failure. In the literature, the bond between asphalt pavements and concrete substrates is usually analyzed using mechanical test methods. With mechanical test methods, the effects of interlocking, glue adhesion and friction, which have an effect at the layer boundary, are not considered individually. Based on previous findings, the aim of this study is to carry out a precise analysis of the bonding at the layer interface between concrete and asphalt using bitumen emulsion by means of measurements with a high-resolution X-ray computer tomography (CT). To determine the effect of the surface texture of the substrate, the investigations were carried out on milled and smooth surface textures. In addition to the variation of the substrate profiles, the influence of the application quantity of the bitumen emulsions C40 B5-S and C60 BP4-S was analyzed by spraying quantities of 90 g/m² and 180 g/m² bitumen after breaking. A newly developed method was used to determine the effective degree of gluing at the layer boundary, which allowed the bonding efficiency to be determined. The results of the calculated degree of gluing for the individual variants show that the highest degree of gluing of 61.94% is achieved with the smooth texture variant and high application quantity of bitumen emulsion. The lowest degree of gluing of 17.01% was achieved with the milled texture variant without the application of bitumen emulsion. Overall, the results showed that the degree of gluing was increased for both surface textures by applying the bitumen emulsion. Compared to the smooth texture, the milled textures exhibit a lower degree of gluing for both bitumen quantities, which could be explained by the distribution of the bitumen emulsions on the substrate profiles.

Visual Saliency Detection using Deep Learning

Salient object discovery models mimic the gesture of human beings and capture the most salient region/ object from the images or scenes. This field has numerous important operations in both computer vision and pattern recognition tasks. Despite hundreds of models proposed in this field, it still has a large room for exploration. This paper demonstrates a detailed overview of the recent progress of saliency discovery models in terms of heuristic- grounded ways and deep literacy- grounded ways. We've bandied and reviewed it’s co-related fields, similar as Eye obsession- vaticination, RGBD salient- object- discovery, co- saliency object discovery, and videotape- saliency- discovery models. Image saliency object discovery can fleetly prize useful information from image scenes and further assay it. At present, the traditional saliency target discovery technology still has the edge of outstanding target that can not be well saved. Convolutional neural network( CNN) can prize largely general deep features from the images and effectively express the essential point information of the images. This paper designs a model which applies CNN in deep saliency object discovery tasks. It can efficiently optimize the edges of focus objects and realize largely effective image saliency discovery through multilayer nonstop point birth, refinement of layered boundary, and original saliency point emulsion. The experimental result shows that the proposed system can achieve further robust saliency discovery to acclimate itself to complex background terrain.

Peculiarities of the electronic properties in the intrinsic magnetic topological insulator MnBi2Te4

The electrical conductivity σ0(T) of single-crystal and polycrystalline samples of the intrinsic magnetic topological insulator MnBi2Te4 was measured in the temperature range from 5 to 300 K. The optical characteristics σ(ω), ɛ1(ω), ɛ2(ω) and R(λ) of MnBi2Te4 were studied in the spectral range from 1250 to 36000 cm−1 at room temperature. The anisotropy of the electrical conductivity of MnBi2Te4 was found, which arises due to the additional contribution from scattering on layer boundaries. The optical spectrum of MnBi2Te4 is formed predominantly due to interband absorption of a light wave. Despite the qualitatively similar behavior of the optical characteristics, there is some difference between poly- and single crystals in infrared region.

CVT grown CuSe single crystals: Unveiling photodetection advancements and thermoelectric promise

Over the past few decades, transition metal chalcogenides garnered global recognition for their noteworthy contributions to the modeling and engineering of electronic, optoelectronic, and thermoelectric devices to improve overall device performance. In the current investigation, the first ever growth of CuSe single crystals is achieved utilizing the chemical vapor transport technique with iodine serving as a transporting medium. The ascertainment of the hexagonal unit cell configuration in the grown CuSe crystals with the P63/mmc space group is substantiated via powder X-ray diffraction examination. The micro-surface characteristics exhibited planar facets outlined by layer boundaries, signifying crystal development through a mechanism reliant on layer growth. The direct optical bandgap of 1⋅64 eV for CuSe single crystals is unveiled by optical reflectance spectrum, demonstrating its aptitude for incorporation into photodetectors. The Raman spectrum manifested a prominent peak at 259 cm−1, aligning to Ag1 vibrational mode. The exploration of temperature-induced fluctuations in the power factor and figure of merit unveiled a progressive increase with rising temperatures. The optimal ZT parameter for the CuSe single crystals attains 0⋅058 at 523 K. The thermogravimetric patterns of CuSe single crystals exhibited singular step decomposition, exemplified by an average weight reduction of 25⋅49 % across the temperature spectrum from ambient to 813 K. The current−voltage (I–V) features of the fabricated CuSe single crystal photodetector are assessed under biasing voltage set at 20 mV at ambient temperature. Under a bias voltage of 20 mV and a polychromatic light intensity of 50 mW/cm2, the achieved responsivity is 4335⋅57 μA/W and a detectivity of 135 × 106 Jones. The photoresponse and thermoelectric examination of CuSe crystals alludes to their potential utility in innovative applications on the horizon.

Corrosion and carburization of Ni3Al‐based superalloys in high‐temperature carbon dioxide

AbstractTo investigate the application of Ni3Al‐based superalloys in gas turbine cycle systems, this experiment exposed Ni3Al‐based superalloys to a 600°C/5 MPa environment with 99.995% pure CO2 gas. The corrosion and carburization behaviors and mechanisms were investigated in detail. The results reveal that with prolonged thermal exposure, the surface oxides of the samples tend to develop a continuous and homogeneous transition state alumina layer. This layer serves as a protective barrier, preventing the penetration and corrosion of external carbon‐containing and oxygen‐containing substances into the matrix. A small amount of carbon‐containing hazardous substances still penetrates the oxide layer or grain boundaries through highly diffusive pathways such as nanochannels, pores, and cracks, because the transition state of alumina is not completely dense. This leads to carbon deposition at the interface between the oxide layer and the matrix, where a mixture of alumina and amorphous carbon is formed at the interface.

Effects of build direction and microstructure on fatigue crack growth behavior of Ti6Al4V fabricated by laser powder bed fusion

AbstractThis study compares the fatigue crack growth (FCG) behavior of Ti6Al4V parts fabricated by laser powder bed melting (LPBF) with four build directions (0°, 30°, 60°, and 90°) and two heat treatments and analyzed the effect of build direction and microstructure on FCG. The results show that the build direction has a significant effect on the FCG rate. Particularly, specimens with 90° build direction have the best FCG resistance while the 0° specimens have the worst. Furthermore, the fragile deposition layer boundary is the main cause of the crack deflection. The microstructure shows that the columnar β grains have less effect on FCG. The increase in resistance to FCG after heat treatment is attributed to the lath‐like α grains consuming the energy for FCG. As compared to needle‐like α′ grains, the lath‐like α grains are more likely to initiate intergranular fracture and secondary cracking, leading to rugged crack tip paths.

Fracture ellipticity as a measure of chemical reaction-controlled fracture growth

Natural fractures are generally viewed as elliptical in shape, consistent with elastic fracture mechanics. To quantify deviations of fracture shape from theoretically predicted elliptical opening distributions and to evaluate processes leading to non-elliptical fracture shapes, we measured aperture profiles of quartz-cemented opening-mode fractures in low-grade metamorphic sandstone. Ellipticity was quantified by the Lamé n-value, with measured n-values deviating significantly from n=2 for elliptical shapes, ranging from 0.7 for tapered fractures to 3.2 for blunted fractures.While some deviation from n=2 can be explained by mechanical interaction with nearby fractures and layer boundaries, we explain the generally observed large variation in n values with competing processes between chemically assisted subcritical fracture propagation, leading to preferred fracture length growth and tapered tips for non-recoverable inelastic fracture opening by solution-precipitation creep, and preferred aperture growth and tip blunting by locally enhanced solution-precipitation creep in the fracture tip region. Using geometric models, we show that preferred length growth with non-recoverable fracture opening strain can lead to tapered fractures with n=1; Preferred aperture growth and opening increments with Lamé n=3 result in overall blunted fracture shapes with n>2. We propose that fracture ellipticity provides a measure of chemically reactive fracture growth processes in geological systems.

Alterations of the Ganglion Cell Complex in Age-Related Macular Degeneration: an AMISH Eye Study Analysis

To compare the Ganglion Cell Complex (GCC) thickness in eyes with age-related macular degeneration (AMD) versus healthy controls in an elderly Amish population DESIGN: Cross-sectional study METHODS: This is a post hoc analysis of the family-based prospective study of Amish subjects. Study subjects were imaged by the Cirrus HD-OCT (Carl Zeiss Meditec Inc, Dublin, CA) using a macular cube protocol of 512 × 128 scans (128 horizontal B-scans, each compromising 512 A-scans) over a 6 mm x 6 mm region centered on the fovea. The ganglion cell analysis algorithm calculated the GCC thickness by segmenting the outer boundaries of the retinal nerve fiber layer (RNFL) and inner plexiform layer (IPL) in all B-scans of the volume, with the region between these boundaries representing the combined thickness of the GCL and the IPL layer. A number of parameters were used to evaluate the GCC thickness: the average GCC thickness, minimum (lowest GCC thickness at a single meridian crossing the elliptical annulus), and sectoral (within each of six sectoral areas: superior, superotemporal, superonasal, inferior, inferonasal, and inferotemporal). The stage of AMD was graded on color fundus photographs in accordance with the Beckman Initiative for Macular Research classification system. Of 1339 subjects enrolled in the Amish eye study, a total of 1294 eyes of twelve hundred and ninety-four subjects had all required imaging studies of sufficient quality and were included in the final analysis, and of these 798 (62%) were female. Following age adjustment, the average GCC thickness was significantly (p<0.001) thinner in AMD subjects (73.71 ± SD; 13.77 µm) compared to normals (77.97 ± 10.42 µm). Independent t test showed that, early (75.03 ± 12.45 µm), and late AMD (61.64 ± 21.18 µm) groups (among which GA eyes had the lowest thickness of 58.10 ± 20.27 microns) had a statistically significant lower GCC thickness compared to eyes without AMD. There was no significant difference in average GCC thickness between early AMD and intermediate AMD (76.36 ± 9.25 µm) eyes. The GCC thickness in AMD eyes is reduced compared to normal eyes, but the relationship is complex with the greatest reduction in late AMD eyes (particularly GA eyes) but no difference between early and intermediate AMD eyes.

Gradient microstructure in Ni-Cr-Mo ultra-heavy steel plate after tempering

This paper studied through-thickness gradient microstructure of an 80mm ultra-heavy steel plate by multi-dimensional characterizations, meanwhile the cause of microstructure variability as well as its effect on strength was analyzed. Results show major lath-structure in the whole steel plate, while lath morphology and grain boundary distribution are different along the thickness direction. During phase transformation, the higher cooling rate in the surface enhances the forming ability of V1/V4 variant pairs and corresponding 5°-10° boundaries, meanwhile the higher cooling rate and smaller original austenite grain contribute to more nucleation sites and stronger strain incompatibility, which is corresponding to more low-angle boundaries, so the surface layer shows higher low-angle boundaries; Compared with the surface layer, the moderate cooling rate is beneficial for V1/V2 variant pairs, and Σ3 boundaries between the pairs are obtained, leading to higher high-angle boundary density with decreased low-angle grain boundary density. This boundary characteristic corresponds to the thinner and longer lath morphology. With respect to the relationship between mechanical properties and microstructure, more low-angle boundaries in the surface layer and more high-angle boundaries in inner layers contribute to stronger dislocation strengthening and grain boundary strengthening respectively, and realizes the coordinated through-thickness property.

Ultra-High Birefringence Property and Low Confinement Loss of Circular Photonic Crystal Fiber for Telecommunication Application

Abstract: A redesigned PCF structure with minimal confinement loss and high birefringence is proposed in this research paper. It employs a circular lattice arrangement with one ring of identical air holes. High birefringence and low confinement loss are two of the properties that have been numerically studied using the finite element method with circular perfectly matched layer boundary conditions. By adjusting the hole size and spacing, it is possible to achieve both properties simultaneously. At an excitation wavelength of 1550 nm, a numerically obtained modal birefringence of 2.3179×10-2 is observed. Simultaneously, by methodically evaluating the cladding rings, the center-to-center distance between the air holes, and the number of cladding rings with equal diameters, a minimal confinement loss (&lt;10-1) may be achieved. Additionally, the suggested PCF verifies that it is feasible to acquire. Our extremely birefringent fiber can be controllably created thanks to the development of birefringence with structural modifications. The suggested structure has better optical characteristics, making it a potential contender for sensing and broadband dispersion correction.

Application of Generalized Reciprocal Method on 2D Seismic Refraction Data in Mt. Manglayang, West Java

The imaging of shallow subsurface structures, weathered rock thickness and velocity propagation distribution of the rocks can be identified by seismic refraction. This method is one of the geophysical exploration methods utilizing refracted wave once it reaches the boundary of subsurface layer. In this research we used the generalized reciprocal method (GRM) as one of the robust processing methods in analyzing subsurface data. This method was chosen due to its accuracy in interpreting shallow subsurface layer with highly undulating refractors by determining time velocity analysis, XY optimum distances, and time depth analysis, then, the expected depth values can be achieved. The acquisition of data for this research was conducted using 13 geophones with forward and reverse sources, the data were then picked to get travel time values and inverted to obtain real geological setting of the earth. The results were interpreted as 2 layers, the first layer had a velocity distribution of 499.289 m/s which was identified as a weathered layer with a thickness of about 4.74 meters, whereas the second layer was interpreted as clay rock with velocity distribution of 1270.433 m/s with the thickness reached up to 16 meters.&#x0D; Keywords: generalized reciprocal method, 2D seismic refraction

Numerical-analytical investigation on bending performance of laminated beams in modular steel buildings

It is well-known that the laminated channel beams can significantly strengthen the combination of adjacent beam components and further enhance the structural integrity of modular steel buildings. In present study, the superimposed bending performance of laminated channel beams was comprehensively investigated using the numerical and analytical methods. Firstly, FE models were developed and validated by the experimental data. Then, a series of numerical parametric studies combining the orthogonal and univariate analysis were successively conducted to identify the sensitivity of design parameters including interfacial bolt number (n), interfacial friction (f), layer height ratio (β), load type (p) and boundary condition (b), and further clarify the influence of key parameters on the cooperative bending properties. Finally, the analytical procedure was proposed to evaluate the equivalent bending stiffness of laminated channel beams. The results showed that the effect degrees of design factors on EIe and Pu were as follows: n > β > f > b > p and p > b > β > f > n, respectively. n and β were selected as the key design parameters for the modular laminated beams. The bending responses were nonlinearly promoted by n, while the linear regularity was observed for β. The influencing mechanism of n indicated that the bolt connections induced the additional internal forces, which caused the transferring of neutral axes and the superimposition effect of laminated beams. Quantifying the neutral axis deviations, the analytical models were developed and reasonably assessed the superimposed bending stiffness of laminated beams in modular steel buildings.

Pressure-Insensitive Epidermal Thickness of Fingertip Skin for Optical Image Encryption.

In this study, an internal fingerprint-guided epidermal thickness of fingertip skin is proposed for optical image encryption based on optical coherence tomography (OCT) combined with U-Net architecture of a convolutional neural network (CNN). The epidermal thickness of fingertip skin is calculated by the distance between the upper and lower boundaries of the epidermal layer in cross-sectional optical coherence tomography (OCT) images, which is segmented using CNN, and the internal fingerprint at the epidermis-dermis junction (DEJ) is extracted based on the maximum intensity projection (MIP) algorithm. The experimental results indicate that the internal fingerprint-guided epidermal thickness is insensitive to pressure due to normal correlation coefficients and the encryption process between epidermal thickness maps of fingertip skin under different pressures. In addition, the result of the numerical simulation demonstrates the feasibility and security of the encryption scheme by structural similarity index matrix (SSIM) analysis between the original image and the recovered image with the correct and error keys decryption, respectively. The robustness is analyzed based on the SSIM value in three aspects: different pressures, noise attacks, and data loss. Key randomness is valid by the gray histograms, and the average correlation coefficients of adjacent pixelated values in three directions and the average entropy were calculated. This study suggests that the epidermal thickness of fingertip skin could be seen as important biometric information for information encryption.

Effect of insolation heating of roof coverings on their performance reliability

Introduction. The article addresses the issues of ensuring the performance reliability of warm roofs in terms of condensation moisture accumulating in their structures, which causes leaks on the upper floors of buildings. Such problems are often revealed when buildings are inspected during repair and reconstruction works. Leaks in the ceilings of buildings with warm roofs were detected in dry, sunny weather with significant heating of the roof covering due to solar radiation.Aim. To examine the effect of the insolation heating of a roof covering on the formation of condensate in the warm roof of a building in summer, taking into account its design solution.Materials and methods. Materials are presented on inspection of buildings in the Moscow region for repair and reconstruction needs; they reveal the problem of leak formation in the warm roofs of buildings on dry, sunny summer days. The process of moisture transfer through the exterior covering was analyzed through analytical calculations using the roof design solution in the considered structure as an example.Results. The calculation of moisture transfer yielded vapor transmission resistance, conventional true and maximum partial pressures of water vapor, as well as temperatures at the layer boundaries in the studied structures. Changes in these parameters across the thickness of structures were revealed via a graphical method, which showed where the dew point indicating possible condensation in the covering is formed. For a comparative analysis, moisture transfer was calculated for a similar design in which mineral wool insulation was replaced by extruded polystyrene.Conclusions. 1. The calculations of moisture transfer in the examined covering designs confirmed the formation of condensate due to the insolation heating of the roof in summer. 2. The choice of a covering design solution in the design of buildings should be based on accurate heat and moisture calculations taking into account climatic conditions in the construction area, including for the summer season.

A Case Study on Advanced CPT Data Interpretation: From Stratification to Soil Parameters

AbstractThe cone penetration test (CPT) is considered as one of the most reliable in-situ tests and has found numerous applications in the geotechnical engineering field. Traditional CPT interpretation includes, but are not limited to the identification of the soil stratification and the determination of soil parameters. This paper presents a case study concerning a test site located in Salzburg, Austria, in which we focus on the interpretation of CPTs from different perspectives. The manuscript is divided into three main sections dealing with three different aspects of CPT interpretation, namely stratification, ground variability and soil parameters. The first strategy introduces a machine learning based stratification identification strategy to detect soil layer boundaries from CPT measurements. A comparison with reference solutions demonstrates relative merits of this approach to classical filter algorithms based on empirical CPT classifications. The second strategy introduces an intuitive approach to evaluate the ground variability. This is achieved by calculating the level of fluctuation on the basis of CPT measurements and could be used as a data-driven decision-making tool for the improved design of CPT investigation layouts. The third strategy is embedded in an ongoing research project that aims to determine constitutive model parameters from in-situ tests using a graph-based methodology. In the present work, the developed automated parameter determination framework is applied to evaluate the soil parameters of one selected soil layer identified from the CPT interpretations. Potential lines of research in the context of CPT interpretation are explored throughout this work and may serve as valuable reference in future research.

Spatial organization of astrocyte clones: The role of developmental progenitor timing.

Astrocytes represent a diverse and morphologically complex group of glial cells critical for shaping and maintaining nervous system homeostasis, as well as responding to injuries. Understanding the origins of astroglial heterogeneity, originated from a limited number of progenitors, has been the focus of many studies. Most of these investigations have centered on protoplasmic and pial astrocytes, while the clonal relationship of fibrous astrocytes or juxtavascular astrocytes has remained relatively unexplored. In this study, we sought to elucidate the morphological diversity and clonal distribution of astrocytes across adult cortical layers, with particular emphasis on their ontogenetic origins. Using the StarTrack lineage tracing tool, we explored the characteristics of adult astroglial clones derived from single and specific progenitors at various embryonic stages. Our results revealed a heterogeneous spatial distribution of astroglial clones, characterized by variations in location, clonal size, and rostro-caudal dispersion. While a considerable proportion of clones were confined within specific cortical layers, others displayed sibling cells crossing layer boundaries. Notably, we observed a correlation between clone location and developmental stage at earlier embryonic stages, although this relationship diminished in later stages. Fibrous astrocyte clones were exclusively confined to the corpus callosum. In contrast, protoplasmic or juxtavascular clones were located in either the upper or lower cortical layers, with certain clones displayed sibling cells distributed across both regions. Our findings underscore the developmental origins and spatial distribution of astroglial clones within cortical layers, providing new insights into the interplay between their morphology, clonal sizes, and progenitor heterogeneity.

Robust and accurate corneal interfaces segmentation in 2D and 3D OCT images.

Segmentation of corneal layer interfaces in optical coherence tomography (OCT) images is important for diagnostic and surgical purposes, while manual segmentation is a time-consuming and tedious process. This paper presents a novel technique for the automatic segmentation of corneal layer interfaces using customized initial layer estimation and a gradient-based segmentation method. The proposed method was also extended to three-dimensional OCT images. Validation was performed on two corneal datasets, one with 37 B-scan images of healthy human eyes and the other with a 3D volume scan of a porcine eye. The approach showed robustness in extracting different layer boundaries in the low-SNR region with lower computational cost but higher accuracy compared to existing techniques. It achieved segmentation errors below 2.1 pixels for both the anterior and posterior layer boundaries in terms of mean unsigned surface positioning error for the first dataset and 2.6 pixels (5.2 μm) for segmenting all three layers that can be resolved in the second dataset. On average, it takes 0.7 and 0.4 seconds to process a cross-sectional B-scan image for datasets one and two, respectively. Our comparative study also showed that it outperforms state-of-the-art methods for quantifying layer interfaces in terms of accuracy and time efficiency.

PLASMON ENERGY LOSSES OF ELECTRONS IN MULTILAYER DIELECTRIC STRUCTURES

The possibilities of engineering energy losses of electrons created in the cascade process of electron-electron scattering during the interaction of multilayer dielectric structures with ionizing radiation are considered. It is shown that the contribution of surface plasmons associated with layer boundaries to electron energy losses is significant only for nanometer layer thicknesses and increases with increasing electron energy. At the same time, surface states associated with longitudinal optical phonons in ionic crystals significantly change energy losses during electron thermalization and can lead to an increase in the efficiency and growth rate of scintillation in nanostructured systems.

Coupled hydromechanical modelling of cone penetration in layered liquefiable soils

Soil layering modifies cone penetration measurements when the cone is close to layer boundaries. Transition zone and thin-layer effects appear, complicating interpretation. To help identify the mechanisms underlying transition and thin-layer effects, several series of realistic simulations of cone penetration in layered soils are presented. Cone penetration tests are simulated using fully coupled hydromechanical models solved with the particle finite-element method. A constitutive model capable of representing flow liquefaction is employed to explore the effect of embedded layers with different initial state parameter and/or hydraulic conductivity than the host soil. Sensing and development distances for tip resistance and excess pore pressure are examined, as well as the effect of layering on dissipation tests. It is shown how distortion of layer interfaces by the cone is captured, explaining several characteristics of pore pressure and dissipation records. It is also shown that looser soil states may be hidden in the tip resistance trace by simultaneous changes in soil hydraulic conductivity.