bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical study on aerodynamic characteristics of the grid fins with different grid patterns
Authors: Dinh Van-Son , Dinh Cong-Truong , Pham Van-Sang
Published: December 2023

Grid fins are unconventional control surfaces configured by a grid of cells within an outer frame; this grid acts as multiple lifting surfaces, and the pattern of the cells strongly affects the grid fin's performance. In this study, three-dimensional simulations were performed using a computational fluid dynamic approach with a k–ω shear stress transport turbulence model to investigate the effect of grid patterns on fin aerodynamic characteristics. Three fin models were designed, including square, tri, and hexa grid patterns, to be more independently comparative; other parameters consisting of the outer frame's dimensions, internal web's thickness, chord length, dragging area, and grid cell area were kept similar between the models. The Mach numbers 0.7, 1.2, and 2.5 corresponding to subsonic, transonic, and supersonic regimes were investigated for varying angles of attack from −5° to 15° for each fin model. The aerodynamic efficiency of grid fins is appreciably improved by increasing the normal force coefficient (CN) while reducing the area force coefficient (CA) and hinge moment coefficient (CHM). The results underscore the hexa grid pattern's superiority, with CN increasing by 2.2% and CA decreasing by 1.92% compared to the square model (the original model) at Mach number 0.7. Especially, the hexa model exhibited a substantial decrease in CHM, with the largest difference being 56.8% compared to the square model at Mach 2.5.
Influence of the magnetic field curvature on the radial–azimuthal dynamics of a Hall thruster plasma discharge with different propellants
Authors: Reza M. , Faraji F. , Knoll A.
Published: December 2023

The topology of the applied magnetic field is an important design aspect of Hall thrusters. For modern Hall thrusters, the magnetic field topology most often features curved lines with a concave (negative) curvature upstream of the field's peak and a convex (positive) curvature downstream. Additionally, the advent of the magnetic shielding technique has resulted in Hall thruster designs with non-conventional field topologies that exhibit high degrees of concavity upstream of the field's peak. In this article, a detailed study is carried out on the effects that the magnetic field curvature has on the plasma discharge in a 2D configuration representative of a Hall thruster's radial–azimuthal cross section. The analyses are performed for discharges of three propellants of high applied interest: xenon, krypton, and argon. For each propellant, high-fidelity electrostatic reduced-order particle-in-cell (PIC) simulations are performed with various degrees of positive and negative curvatures of the magnetic field. Corresponding 1D radial PIC simulations are also performed for xenon to compare the observations against the 2D results. Most notably, it is observed that the instability spectra in the positive-curvature cases are mostly dominated by electron cyclotron drift instability, whereas the modified two stream instability is dominant in the negative-curvature cases. The distributions of electron and ion temperatures, in particular, as well as the contribution of various mechanisms to electrons’ cross-field transport show notable variations between the positive and negative curvature values. Finally, the field curvature is observed to majorly influence the ion beam divergence along the radial and azimuthal coordinates.
Quasi-deterministic localization of Er emitters in thin film TiO2 through submicron-scale crystalline phase control
Authors: Sullivan Sean E. , Ahn Jonghoon , Zhou Tao , Saha Preetha , Holt Martin V. , Guha Supratik , Heremans F. Joseph , Singh Manish Kumar
Published: December 2023

With their shielded 4f orbitals, rare-earth ions (REIs) offer optical and electron spin transitions with good coherence properties even when embedded in a host crystal matrix, highlighting their utility as promising quantum emitters and memories for quantum information processing. Among REIs, trivalent erbium (Er3+) uniquely has an optical transition in the telecom C-band, ideal for transmission over optical fibers, making it well suited for applications in quantum communication. The deployment of Er3+ emitters into a thin film TiO2 platform has been a promising step toward scalable integration; however, like many solid-state systems, the deterministic spatial placement of quantum emitters remains an open challenge. We investigate laser annealing as a means to locally tune the optical resonance of Er3+ emitters in TiO2 thin films on Si. Using both nanoscale x-ray diffraction measurements and cryogenic photoluminescence spectroscopy, we show that tightly focused below-gap laser annealing can induce anatase to rutile phase transitions in a nearly diffraction-limited area of the films and improve local crystallinity through grain growth. As a percentage of Er:TiO2 is converted to rutile, the Er3+ optical transition blueshifts by 13 nm. We explore the effects of changing laser annealing time and show that the amount of optically active Er:rutile increases linearly with laser power. We additionally demonstrate local phase conversion on microfabricated Si structures, which holds significance for quantum photonics.
Innovative coatings for reducing flow-induced cylinder noise by altering the sound diffraction
Authors: Zamponi R. , Ragni D. , van der Zwaag S. , Avallone F.
Published: December 2023

The aerodynamic noise radiated by the flow past a cylinder in the subcritical regime can be modeled by a quadrupolar sound source placed at the onset position of the vortex-shedding instability that is scattered by the surface with a dipolar directivity. When the cylinder is coated with a porous material, the intensity of the shed vortices is greatly reduced, determining a downstream shift of the instability-outbreak location. Consequently, sound diffraction is less efficient, and noise is mitigated. In this paper, an innovative design approach for a flow-permeable coating based on a further enhancement of such an effect is proposed. The results of phased-microphone-array measurements show that, once the leeward part of the cover is integrated with components that make the flow within the porous medium more streamlined, the quadrupolar source associated with the vortex-shedding onset is displaced more downstream, yielding additional noise attenuation of up to 10 dB with respect to a uniform coating. Furthermore, the same noise-control mechanism based on the weakening of the sound scattering can be exploited when these components are connected to the bare cylinder without the porous cover. In this case, the mitigation of overall sound pressure levels is comparable to that induced by the coated configurations due to the lack of noise increase produced by the inner flow interacting within the pores of the material. Remarkable sound reductions of up to 10 dB and a potential drag-force decrease are achieved with this approach, which paves the way for disruptive and more optimized noise-attenuation solutions.
1530-nm electroluminescence from p-Ga2S3:Er/n+-Si heterojunctions induced by Zener tunneling
Authors: Wang Lei , Ji Xiaohong , Zhang Qinyuan
Published: December 2023

Silicon-based near-infrared (NIR) light sources with a simple structure are significant for circuit integration and fiber optic communications. Herein, 1530-nm electroluminescence (EL) from p-Ga2S3:Er/n+-Si junction light-emitting devices (LEDs) is reported with Er-doped Ga2S3 nanofilms as the photoemission layer and heavily doped n-type silicon as the substrate. The 1530-nm EL emission is attributed to the energy transfer between the Ga2S3 host and the Er3+ dopant, and it reaches its maximum at Er-doping concentration of 1 mol. % as the device works at −4.8 mA. The Er-related NIR EL occurs only at reverse voltages because the holes and electrons for recombination in Ga2S3:Er come from the Zener tunneling in the depletion region and the direct ITO injection, respectively. The realization of 1530-nm p-Ga2S3:Er/n+-Si LEDs offers opportunities for silicon-based integrated light sources.
Lubrication approximation of pressure-driven viscoelastic flow in a hyperbolic channel
Authors: Housiadas Kostas D. , Beris Antony N.
Published: December 2023

We investigate theoretically the steady incompressible viscoelastic flow in a hyperbolic contracting channel. The fluid viscoelasticity is modeled using the upper convected Maxwell (UCM), Oldroyd-B, Phan-Thien and Tanner (PTT), Giesekus, and the finite elasticity non-linear elastic dumbbell with the Peterlin approximation (FENE-P) models. We first develop the general governing equations for flow within a non-deformable channel whose cross section varies with the distance from the inlet. We then exploit the classic lubrication approximation, assuming a small aspect ratio of the channel to simplify the original governing equations. The final equations, which we formulate in terms of the stream unction, are then solved analytically using a high-order asymptotic scheme in terms of the Deborah number, De, and the formulas for the average pressure drop are derived up to eight orders in De. The accuracy of the original perturbation solution is enhanced and extended over a wide range of parameters by implementing a convergence acceleration method for truncated series. Furthermore, convergence of the transformed solutions for the average pressure drop is demonstrated. The validity and accuracy of the theoretical results is independently confirmed through comparison with numerical results from simulations performed using high-order finite differences and pseudospectral methods. The results reveal the decrease in the average pressure drop with increasing the Deborah number, the polymer viscosity ratio, and the ratio of the inlet to the outlet height. We also show that the fundamental UCM and Oldroyd-B models can predict the major viscoelastic phenomena for this type of internal and confined lubrication flows, while the effect of the rheological parameters of the PTT, Giesekus, and FENE-P models on the results is minor.
Design and test of rack-integrated cavity combiner for China initiative accelerator driven system project
Authors: Pan Chao , Shi Longbo , Wu Zhengrong , Jin Kean , Jiang Guodong , Sun Liepeng , Huang Guirong , Qiu Feng , Sun Duixiong
Published: December 2023

The next-generation 650 MHz solid state power amplifier designed by the Institute of Modern Physics will utilize 24 modules with an output power of 60 kW. The outputs of each of the 12 modules will be combined using a 12-in-1 rectangular cavity combiner integrated into the rack. This cavity combiner, requiring only a single stage to combine power, is characterized by a minimal power loss and a high combining efficiency. The input couplers of the combiner are adjustable to change the number of combination channels. In the event of one amplifier module failure, the corresponding port can be adjusted to decouple, transforming the combiner to an (N-1)-channel combiner with a combining efficiency decay of 0.2%. The prototype of the combiner has been fabricated and tested with a small signal. The combining efficiency is 98.5%. In this paper, we will validate the feasibility of the combiner from the design, simulation, and experiment.
Highly specific σ
2
R/TMEM97 ligand FEM-1689 alleviates neuropathic pain and inhibits the integrated stress response
Authors: Yousuf Muhammad Saad , Sahn James J. , Yang Hongfen , David Eric T. , Shiers Stephanie , Mancilla Moreno Marisol , Iketem Jonathan , Royer Danielle M. , Garcia Chelsea D. , Zhang Jennifer , Hong Veronica M. , Mian Subhaan M. , Ahmad Ayesha , Kolber Benedict J. , Liebl Daniel J. , Martin Stephen F. , Price Theodore J.
Published: December 2023

The sigma 2 receptor (σ
2
R) was described pharmacologically more than three decades ago, but its molecular identity remained obscure until recently when it was identified as transmembrane protein 97 (TMEM97). We and others have shown that σ
2
R/TMEM97 ligands alleviate mechanical hypersensitivity in mouse neuropathic pain models with a time course wherein maximal antinociceptive effect is approximately 24 h following dosing. We sought to understand this unique antineuropathic pain effect by addressing two key questions: do these σ
2
R/TMEM97 compounds act selectively via the receptor, and what is their downstream mechanism on nociceptive neurons? Using male and female conventional knockout mice for
Tmem97,
we find that a σ
2
R/TMEM97 binding compound, FEM-1689, requires the presence of the gene to produce antinociception in the spared nerve injury model in mice. Using primary mouse dorsal root ganglion neurons, we demonstrate that FEM-1689 inhibits the integrated stress response (ISR) and promotes neurite outgrowth via a σ
2
R/TMEM97-specific action. We extend the clinical translational value of these findings by showing that FEM-1689 reduces ISR and p-eIF2α levels in human sensory neurons and that it alleviates the pathogenic engagement of ISR by methylglyoxal. We also demonstrate that σ
2
R/TMEM97 is expressed in human nociceptors and satellite glial cells. These results validate σ
2
R/TMEM97 as a promising target for further development for the treatment of neuropathic pain.
ENPP1 is an innate immune checkpoint of the anticancer cGAMP–STING pathway in breast cancer
Authors: Wang Songnan , Böhnert Volker , Joseph Alby J. , Sudaryo Valentino , Skariah Gemini , Swinderman Jason T. , Yu Feiqiao B. , Subramanyam Vishvak , Wolf Denise M. , Lyu Xuchao , Gilbert Luke A. , van’t Veer Laura J. , Goodarzi Hani , Li Lingyin
Published: December 2023

Ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1) expression correlates with poor prognosis in many cancers, and we previously discovered that ENPP1 is the dominant hydrolase of extracellular cGAMP: a cancer-cell-produced immunotransmitter that activates the anticancer stimulator of interferon genes (STING) pathway. However, ENPP1 has other catalytic activities and the molecular and cellular mechanisms contributing to its tumorigenic effects remain unclear. Here, using single-cell RNA-seq, we show that ENPP1 in both cancer and normal tissues drives primary breast tumor growth and metastasis by dampening extracellular 2′3′-cyclic-GMP-AMP (cGAMP)–STING-mediated antitumoral immunity. ENPP1 loss-of-function in both cancer cells and normal tissues slowed primary tumor growth and abolished metastasis. Selectively abolishing the cGAMP hydrolysis activity of ENPP1 phenocopied ENPP1 knockout in a STING-dependent manner, demonstrating that restoration of paracrine cGAMP–STING signaling is the dominant anti-cancer mechanism of ENPP1 inhibition. Finally,
ENPP1
expression in breast tumors deterministically predicated whether patients would remain free of distant metastasis after pembrolizumab (anti-PD-1) treatment followed by surgery. Altogether, ENPP1 blockade represents a strategy to exploit cancer-produced extracellular cGAMP for controlled local activation of STING and is therefore a promising therapeutic approach against breast cancer.
Anion efflux mediates transduction in the hair cells of the zebrafish lateral line
Authors: Lunsford Elias T. , Bobkov Yuriy V. , Ray Brandon C. , Liao James C. , Strother James A.
Published: December 2023

Hair cells are the principal sensory receptors of the vertebrate auditory system, where they transduce sounds through mechanically gated ion channels that permit cations to flow from the surrounding endolymph into the cells. The lateral line of zebrafish has served as a key model system for understanding hair cell physiology and development, often with the belief that these hair cells employ a similar transduction mechanism. In this study, we demonstrate that these hair cells are exposed to an unregulated external environment with cation concentrations that are too low to support transduction. Our results indicate that hair cell excitation is instead mediated by a substantially different mechanism involving the outward flow of anions. Further investigation of hair cell transduction in a diversity of sensory systems and species will likely yield deep insights into the physiology of these unique cells.
A conserved transcriptional program for MAIT cells across mammalian evolution
Authors: Bugaut Hélène , El Morr Yara , Mestdagh Martin , Darbois Aurélie , Paiva Rafael A. , Salou Marion , Perrin Laetitia , Fürstenheim Mariela , du Halgouet Anastasia , Bilonda-Mutala Linda , Le Gac Anne-Laure , Arnaud Manon , El Marjou Ahmed , Guerin Coralie , Chaiyasitdhi Atitheb , Piquet Julie , Smadja David M. , Cieslak Agata , Ryffel Bernhard , Maciulyte Valdone , Turner James M.A. , Bernardeau Karine , Montagutelli Xavier , Lantz Olivier , Legoux François
Published: December 2023

Mucosal-associated invariant T (MAIT) cells harbor evolutionarily conserved TCRs, suggesting important functions. As human and mouse MAIT functional programs appear distinct, the evolutionarily conserved MAIT functional features remain unidentified. Using species-specific tetramers coupled to single-cell RNA sequencing, we characterized MAIT cell development in six species spanning 110 million years of evolution. Cross-species analyses revealed conserved transcriptional events underlying MAIT cell maturation, marked by ZBTB16 induction in all species. MAIT cells in human, sheep, cattle, and opossum acquired a shared type-1/17 transcriptional program, reflecting ancestral features. This program was also acquired by human iNKT cells, indicating common differentiation for innate-like T cells. Distinct type-1 and type-17 MAIT subsets developed in rodents, including pet mice and genetically diverse mouse strains. However, MAIT cells further matured in mouse intestines to acquire a remarkably conserved program characterized by concomitant expression of type-1, type-17, cytotoxicity, and tissue-repair genes. Altogether, the study provides a unifying view of the transcriptional features of innate-like T cells across evolution.
On the gravitational precession memory effect for an ensemble of gyroscopes
Authors: Moti Raihaneh , Shojai Ali
Published: December 2023

We study the thermodynamic properties of a freely falling ensemble of gyroscopes after the passage of a weak gravitational wave. Due to the precession memory effect, the thermodynamic quantities will experience a change because of the space-time perturbation. We discuss that this GravoThermo memory effect potentially can be used for the detection of the gravitational waves.
General spherically symmetric solution of Cotton gravity
Authors: Gogberashvili Merab , Girgvliani Ani
Published: December 2023

In this paper we present the general spherically symmetric static solution to the vacuum equations of Cotton gravity. The obtained metric solution reveals the presence of singularities at the photosphere of a spherical source, which probably obstruct the formation of the stellar Schwarzschild-radius black holes. The solution is characterized by two integration constants, whose values can be restricted by association with the Hubble horizon. We examine the diverse features of the solution, including the long-range modifications to Newton’s force through the incorporation of the velocity-squared repulsive term to model the dark energy.
Structural insight into nanoscale inhomogeneity of electrical properties in highly conductive polycrystalline ZnO thin films doped using methane
Authors: Vasin A V , Gomeniuk Y V , Lytvyn P M , Rusavsky A V , Mamykin S V , Tyagulsky I P , Bortchagovsky E , Havryliuk Ye , Tiagulskyi S I , Yatskiv R , Grym J , Zahn D R T , Nazarov A N
Published: December 2023

Recently, methane has been demonstrated as an effective n-type dopant for ZnO thin films deposited using the RF-magnetron sputtering method. It was shown that the major electrical doping effect of methane is caused by hydrogen released during methane decomposition. This work investigates the origin of the observed increase in conductivity of methane-doped ZnO films with the increase in thickness. The study is aimed at describing the nature of this thickness-dependent effect through a detailed analysis of the thickness-dependent morphology and crystalline structure. A combination of structural, electrical, and optical characterization revealed a transition from fine-grained films with a random orientation at early stages to partially (002)-textured films with columnar grains at later stages of growth. It is demonstrated that grain/sub-grain boundaries increase the electrical conductivity and that the contribution of such buried inner boundaries increases with increasing thickness. It is proposed that hydrogen diffuses along the grain and sub-grain boundaries during growth, leading to continuous doping of the buried interfaces. This hydrogen diffusion mechanism results in an apparent ‘additional doping’ of thicker films. The results provide new insights into the thickness-dependent conductivity of doped polycrystalline ZnO films mediated by hydrogen diffusion along internal interfaces.
Boosted near-infrared shielding properties of cesium-tungsten bronze based on solid state reaction with optimized precursor
Authors: Zhang Bo , Liu Jian Qiang , Wang Dian Yuan , An Feng Hui , Xu Liang
Published: December 2023

Cesium doped tungsten bronze (CWO) nanoparticles can selectively keep high transmittance in the visible while presenting significant shielding rate in the near-infrared region. How to further improve the optical properties of CWO based on solid state method is crucial to the industry production. Based on changing the particle size and morphology of WO3 precursors, cesium-tungsten bronze powders with different dispersivity and concentrations of Cs+ doping were successfully prepared by solid-phase method. The characterization analysis reveals that the precursors with appropriated surface area and morphology are significant to improve the dispersivity of CWO nanocrystal and increase the density of free carriers, thereby improving the small polariton absorption performance and the local surface plasmon resonance effect. The result provides an effective strategy to boost the optical property of CWO nanocrystal synthesized by optimizing the morphology and size of precursor, which is important to the industry production and practical applications in the field of energy-saving window films.
Study of interferometric signal correction methods in ultra-precision displacement measurement
Authors: Xie Zhangning , Jin Tao , Lei Lihua , Lin Zichao , Yao Yulin , Xue Dongbai , Dun Xiong , Deng Xiao , Cheng Xinbin
Published: December 2023

The measurement of critical dimensions in the field of integrated circuits has moved from 7 nm to 5 nm. The existing chromium atomic lithography grating has a pitch period of 4700 l mm−1 and uniformity of picometer, and the interferometric signal period based on the above grating is as small as 106.4 nm, which brings new problems and challenges to the accurate processing of the signal. This paper investigates the error characteristics of ultra-high precision grating interferometric signals, establishes a Heydemann correction mathematical model for high inscribed line density grating interferometric signals, corrects the grating interferometer signals based on the random sample consensus (RANSAC), and verifies the effectiveness of the algorithm through simulation. By comparing the repeatability and linearity of the original algorithm and the self-traceable grating interferometric displacement measurement data processed by RANSAC, the conclusion that the standard deviation of the self-traceable grating interferometer repeat measurement after RANSAC is 1.60 nm in a 10 000 nm travel is obtained, and the purpose of improving the stability and uniformity of the signal solution with the algorithm of this paper is achieved, which is important for the study of laser interferometer and grating interferometer The results show that the stability and uniformity of the signal solution can be improved by the algorithm of this paper, which is of great significance for the study of the displacement solution of laser and grating interferometers.
Development of a vehicle-mounted soil organic matter detection system based on near-infrared spectroscopy and image information fusion
Authors: Cao Yongyan , Yang Wei , Li Hao , Zhang Hao , Li Minzan
Published: December 2023

In the practical application of farmland, the soil organic matter prediction model established by the traditional near-infrared (NIR) spectroscopy is affected by factors such as soil texture, which leads to a serious decline in the accuracy of the model. To improve the robustness and prediction accuracy of the model, a prediction model based on NIR spectroscopy and image fusion is proposed. A 1D-CNN organic matter prediction model (based on NIR spectroscopy) was established using eight characteristic wavelengths of extracted soil organic matter (932 nm, 999 nm, 1083 nm, 1191 nm, 1316 nm, 1356 nm, 1583 nm, and 1626 nm) as spectral information. A 2D -CNN organic matter prediction model was established using soil RGB images as information. Based on the idea of model weight fusion, 1D-CNN and 2D-CNN models are fused. When using small convolutional kernels (three-layer convolutional kernel size: 3*3, 1*1, 1*1) and 1D-CNN:2D-CNN = 6:4, the model has the highest prediction accuracy (R
2 = 0.872). The optimal fusion model was embedded into the inspection system. The final laboratory and field testing results are as follows: under laboratory conditions, the detection accuracy R
2 of the 1D CNN prediction model, 2D-CNN prediction model, and fusion model are 0.838, 0.781, and 0.869, respectively. The root mean square error is 3.005, 3.546, and 2.678, respectively. The above experimental data indicates that the R
2 of the fused model is more accurate compared to the model established with a single information. In the field test, the R
2 detection accuracy of 1D-CNN prediction model, 2D-CNN prediction model and fusion model is 0.809, 0.731 and 0.835, respectively. The root mean square errors are 3.466, 3.828 and 2.973, respectively. The results show that the fusion model improves the prediction accuracy and model robustness, and the detection system can meet the needs of soil nutrient detection in farmland.
Task-based detectability in anatomical background in digital mammography, digital breast tomosynthesis and synthetic mammography
Authors: Monnin P , Damet J , Bosmans H , Marshall N W
Published: December 2023

Objective. Determining the detectability of targets for the different imaging modalities in mammography in the presence of anatomical background noise is challenging. This work proposes a method to compare the image quality and detectability of targets in digital mammography (DM), digital breast tomosynthesis (DBT) and synthetic mammography. Approach. The low-frequency structured noise produced by a water phantom with acrylic spheres was used to simulate anatomical background noise for the different types of images. A method was developed to apply the non-prewhitening observer model with eye filter (NPWE) in these conditions. A homogeneous poly(methyl) methacrylate phantom with a 0.2 mm thick aluminium disc was used to calculate 2D in-plane modulation transfer function (MTF), noise power spectrum (NPS), noise equivalent quanta, and system detective quantum efficiency for 30, 50 and 70 mm thicknesses. The in-depth MTFs of DBT volumes were determined using a thin tungsten wire. The MTF, system NPS and anatomical NPS were used in the NPWE model to calculate the threshold gold thickness of the gold discs contained in the CDMAM phantom, which was taken as reference. Main results. The correspondence between the NPWE model and the CDMAM phantom (linear Pearson correlation 0.980) yielded a threshold detectability index that was used to determine the threshold diameter of spherical microcalcifications and masses. DBT imaging improved the detection of masses, which depended mostly on the reduction of anatomical background noise. Conversely, DM images yielded the best detection of microcalcification
s. Significance. The method presented in this study was able to quantify image quality and object detectability for the different imaging modalities and levels of anatomical background noise.
Correlation of strontium anharmonicity with charge-lattice dynamics of the apical oxygens and their coupling to cuprate superconductivity
Authors: Conradson Steven D , Velasco Victor , Silva Neto Marcello B , Jin Chang-Qing , Li Wen-Min , Cao Li-Peng , Gauzzi Andrea , Karppinen Maarit , Perali Andrea , Wimberger Sandro , Bishop Alan R , Baldinozzi Gianguido , Latimer Matthew , Gilioli Edmondo
Published: December 2023

By means of Cu K edge x-ray absorption spectra of overdoped high-pressure oxygenated superconducting

Y
S

r
2

C

u

2.75

M

o

0.25

O

7.54

and

S

r
2

C
u

O

3.3

, we demonstrate a remarkably strong three way correlation between the superconductivity and the local dynamics of their highly anharmonic Cu–Sr and Cu-apical O pairs. We model the latter as aspects of the Internal Quantum Tunneling Polarons (IQTPs) that give the two-site distributions in extended x-ray absorption fine structure and inelastic pair distribution function measurements. This finding obviates the common assumption that the universal Ba/Sr-apical O dielectric layer, far from only maintaining the separation of charges between the charge reservoir and the

C
u

O
2

conducting domains, plays an unexpectedly active role in the unusual electronic properties of cuprate superconductors. Furthermore, we investigate the effects of the dynamic structure associated with these pairs by means of the exact diagonalization of a prototype Hamiltonian based on a six-atom cluster, with two neighboring Cu-apical O pairs bridged by an anharmonically coupled Sr atom and a planar O atom. In terms of the Kuramoto model for synchronization, these calculations show a first order phase transition, driven by anharmonicity, to a synchronized state of the IQTPs, in which a fraction of the charge originally confined to the apical O sites is transferred onto the planar O in the superconducting plane. This combination of experimental results and theory demonstrates that the Ba/Sr-apical O layer of cuprates most likely plays an important role in high temperature superconductivity via its collective charge dynamics.
Bandgap engineering and tuning of optoelectronic properties of 2D NbSe2/MoS2 heterostructure using first principle computations
Authors: Irfan Muhammad , Ehsan Siddique Akhtar , Pang Wenhui , Sattar Abdul , Mustafa Hina , Latif Hamid , Qin Shengyong
Published: December 2023

This study performed first-principles calculations based on density functional theory to study the interlayer electronic and optical properties of NbSe2/MoS2 heterostructures. Bandgap in 2H-MoS2 is often quite large typically around 1.8 eV, showing slow response time and low photoresponsivity (R); however, a slight bandgap variation can improve the properties of semiconducting and conducting heterostructures. Different stacking configurations of the interlayer van der Waals interaction were precisely investigated. Due to their unique properties, atomically thin NbSe2/MoS2 based heterostructures hold great potential for future electronic and optoelectronic devices. LDA, GGA, GGA with SOC, and HSE06 are used to study the monolayers of MoS2, NbSe2, and their T and H stacking structures. Our results demonstrate that the metallic NbSe2 effect on the semi-metallic MoS2 reduces the band gap of MoS2 up to 140 meV. Moreover, these heterostructures exhibit outstanding absorption properties from visible to ultraviolet regions, which makes them ideal candidates for optoelectronic applications, particularly in photodetectors.
Verifiable visually meaningful image encryption algorithm based on compressive sensing and (t, n)-threshold secret sharing
Authors: Yang Yu-Guang , Wang Tao , Zhou Yi-Hua , Shi Wei-Min , Jiang Dong-Hua , Liao Xin
Published: December 2023

A verifiable visually meaningful image encryption algorithm based on compressive sensing and (t, n)-threshold secret sharing is proposed. Firstly, the plain image is compressed and encrypted by 2D block compressive sensing to obtain the pre-encrypted image. During this process, the enhanced logistic map and the enhanced tent map are used to generate the measurement matrix and the permutation sequence, respectively. Secondly, multiple shadow images of the pre-encrypted image are generated by using the (t, n)-threshold secret sharing scheme, and then each shadow image is further encrypted by using the encryption matrix generated by the chaotic system. Meanwhile, the signatures of the shadow images are obtained by using RSA signature algorithm. Finally, the shadow images and their corresponding signatures are embedded into the carrier image to generate the cipher image with high visual quality by using the LSB method. Additionally, the present algorithm can resist known-plaintext and chosen-plaintext attacks by incorporating the hash value of the plain image as part of the key. Meanwhile, the use of 2D block compressive sensing significantly reduces the reconstruction time. Simulation results demonstrate that the proposed algorithm achieves excellent decryption quality and operational efficiency.
Velocity slip effect on magnetized casson nanofluid over shrinking/stretching cylinder: duality and stability analysis
Authors: Yashkun Ubaidullah , Lund Liaquat Ali , Fadhel Mustafa Abbas , Shah Nehad Ali
Published: December 2023

The aim of current research is to assess heat transfer characteristics over a cylinder undergoing stretching or shrinking using Cason Nanofluid. Additionally, dual solutions stability has been analyzed. The governing equations for the two-phase model consist of partial differential equations (PDEs), which are subsequently transformed into ordinary differential equations (ODEs) using the similarity transformation. The MATLAB software’s bvp4c solver is then used to numerically solve the transformed ODEs. The graph also shows the results of skin friction coefficient, heat transfer coefficient, and the Sherwood number. Furthermore, the validity of the current data is confirmed and shown to be in good agreement by comparing them to the existing literature. The variation of Casson nano fluid velocity, which is the variation of reduced skin friction coefficient

(

Re

x

1
/
2

)

C

f

,

increases as the Casson fluid parameter

β

values increase. The critical values against

β
=
5
,
10

and

∞

are

λ

c
1

=
−
1.1404
,

λ

c
2

=
−
1.2501

and

λ

c
3

=
−
1.4
116

respectively. The temperature variation indicates that the local Nusselt number variation

−
θ
′
(
0
)

decreases as the curvature parameter

γ

values increase. The first solution is characterized by positive values of the smallest eigenvalues

ε

1

>
0
,

suggesting stability. Conversely, the second solution is associated with negative values of the smallest eigenvalues

ε

1

<
0
,

indicating instability. To identify the stable and physically feasible solution, a stability analysis is performed. Graphical analysis is used to examine the influence of relevant physical parameters on the profiles of temperature, concentration, velocity and momentum.
Investigation on Ion extraction processes in M-Type electrode configuration and the influence of top electrode
Authors: Singh Priti , Maiti Namita
Published: December 2023

In the realm of ion extraction from photoplasma, the design of electrode configuration exerts a significant influence over-extraction efficiency by tailoring the vacuum gap and electric potential distribution. Over time, various electrode configurations have been explored, including parallel-plate, wire-type, M-type, and Π-type designs. Notably, the M-type configuration has shorter ion extraction times. In the present study, a comprehensive investigation of the ion extraction process with the M-Type setup is performed using a 2D2v-electrostatic Particle-in-Cell simulation. The study focuses on the spatiotemporal evolution of photoplasma, the formation of the plasma sheath, and the spatial distribution of electric potential. Subsequently, a series of computational experiments have been conducted by systematically altering the size of the top electrode in the M-type configuration, effectively transforming it into wire-type and Π-type. The objective of these experiments is to explore the impact of the top electrode on ion extraction. The obtained simulation results report a significant finding: the formation of a virtual anode between the cathodes. This distinct phenomenon substantially contributes to an exceptional level of efficiency, exceeding 90%, among different simulated configurations. Furthermore, it also reports an approximate 95% collection efficiency with minimum collection time with an M-type configuration over the Π-type electrode configuration.
The Aharonov–Bohm effect in quadratic Gauss quantum rings
Authors: Citrin D S
Published: December 2023

We outline a theory for the Aharonov–Bohm effect in a novel type of quantum ring, namely the quadratic Gauss quantum ring, here for brevity called the Gauss ring. A Gauss ring is a one-dimensional nonperiodic lattice with sites at z = z

j
= j

n

d with j ∈ {0, 1, 2, ⋯ , s + 1} (

s
∈
W

), n ≥ 2 (

n
∈
N

), and d the underlying period wrapped into a ring-shaped geometry. Here we discuss the electronic spectrum of quadratic Gauss rings (n = 2, s ∈ {0, 1, 2, ⋯ , 5, 6, 7}), and show that the spectrum can be described using theoretical tools recently devised to provide an understanding of the Gauss chain [D S Citrin (2023) Phys. Rev. B 107, 235 144]. We then consider the effect on the electronic states of a magnetic flux Φ threading the Gauss ring and show that the effect of the flux is to select specific electronic states from a periodic chain whose supercells are finite-length Gauss chains thus relating the states in the Gauss quantum ring with those in a periodic Gauss chain.
Structural, electronic, optical, and mechanical properties of cubic perovskite LaMnX3 (X = Cl, Br, I) compound for optoelectronic applications: a DFT study
Authors: Shahzad Muhammad Khuram , Sana Aysha , Tahir Muhammad Bilal , Khalil Adnan , Khan Sajjad Ahmad , Karim Shahid , Azeem Waqar , Ahmad Naushad
Published: December 2023

Perovskite materials are used extensively in the area of material science for theoretical computations. Density functional theory (DFT) calculations are used in this study to determine the properties of the cubic halide perovskite LaMnX3 (X = Cl, Br, and I). These compounds contain PM3M-221 space groups and a cubic structure. They were created via the Cambridge serial total energy package (CASTEP) program, which also used HSE (Heyd–Scuseria–Ernzerhof) exchange–correlation functionals. The structural, electrical, optical, and mechanical characteristics of the compounds are determined.LaMnCl3, LaMnBr3, and LaMnI3all have direct bandgaps of 2.366 eV, 1.844 eV, and 1.579 eV, respectively, based on their structural characteristics. Total and partial densities of states (TDOS and PDOS) offer proof of the degree of electron localization in specific bands. Electronic studies indicate that LaMnX3 materials (X = Cl, Br, I) are semiconductors. The dielectric function’s extensive range of energy transparency can be seen in the imaginary element dispersion. LaMnCl3 compound’s absorption and conductivity are preferable to those of LaMnBr3 and LaMnI3, improving its applicability for Optoelectronic applications and work function. We found that the cubic structures of all three compounds allow them to be mechanically stable. The calculated elastic results also satisfy the compound’s mechanical strength requirements. Such materials are used in optoelectronic applications.
Highly ordered structure and susceptibility to light absorption of ZnO/calcium phosphate (5%) to enhance the stability of charge diffusion as a methylene blue bond breaker
Authors: Abdullah Buakar , Tahir Dahlang , Heryanto Heryanto , Tang Nurul Fajri R , Rahmat Roni
Published: December 2023

The composite Zinc oxide/calcium phosphate was successfully prepared using the sol–gel method. The structural and optical properties are observed by using x-ray Diffraction and Fourier Transform Infra-Red, respectively. The degradation of MB dye is analyzed by using Ultraviolet-Visible spectrometer. The maximum MB degradation is achieved 92.61

±

2.7% and shows the linear correlation to a high optical longitudinal position and enlarged d spacing. Superior photocatalytic activity is demonstrated by ZnO/CP_240 which has a consistent band gap due to its highly ordered structure and susceptibility to light absorption ability, thus triggering better charge diffusion stability. The empirical findings suggest that the introduction of CP at the atomic level into the crystal lattice of ZnO buffer generates a surplus of oxygen vacancies, thereby diminishing the strength of the MB bonding. This, in turn, facilitates the activation of lattice oxygen.
Complementary monogamy and polygamy properties among multipartite systems
Authors: Li 李 Tao 陶 , Zhou 周 Jing-Yi 静怡 , Sun 孙 Qi 琪 , Jin 靳 Zhi-Xiang 志祥 , Liang 梁 Deng-Feng 登峰 , Luo 罗 Ting 婷
Published: December 2023

Monogamy and polygamy relations are essential properties of quantum entanglement, which characterize the distributions of entanglement in multipartite systems. In this paper, we establish the general monogamy relations for γ-th (0 ≤ γ ≤ α, α ≥ 1) power of quantum entanglement based on unified-(q,s) entanglement and polygamy relations for δ-th (δ ≥ β, 0 ≤ β ≤ 1) power of entanglement of assistance based on unified-(q,s) entanglement of assistance, which provides a complement to the previous research in terms of different parameter regions of γ and δ. These results are then applied to specific quantum correlations, e.g., entanglement of formation, Renyi-q entanglement of assistance and Tsallis-q entanglement of assistance to get the corresponding monogamy and polygamy inequalities. Moreover, typical examples are presented for illustration.
One-shot random forest model calibration for hand gesture decoding
Authors: Jiang Xinyu , Ma Chenfei , Nazarpour Kianoush
Published: December 2023

Objective. Most existing machine learning models for myoelectric control require a large amount of data to learn user-specific characteristics of the electromyographic (EMG) signals, which is burdensome. Our objective is to develop an approach to enable the calibration of a pre-trained model with minimal data from a new myoelectric user. Approach. We trained a random forest (RF) model with EMG data from 20 people collected during the performance of multiple hand grips. To adapt the decision rules for a new user, first, the branches of the pre-trained decision trees were pruned using the validation data from the new user. Then new decision trees trained merely with data from the new user were appended to the pruned pre-trained model. Results. Real-time myoelectric experiments with 18 participants over two days demonstrated the improved accuracy of the proposed approach when compared to benchmark user-specific RF and the linear discriminant analysis models. Furthermore, the RF model that was calibrated on day one for a new participant yielded significantly higher accuracy on day two, when compared to the benchmark approaches, which reflects the robustness of the proposed approach. Significance. The proposed model calibration procedure is completely source-free, that is, once the base model is pre-trained, no access to the source data from the original 20 people is required. Our work promotes the use of efficient, explainable, and simple models for myoelectric control.
A spiking neural network with continuous local learning for robust online brain machine interface
Authors: Taeckens Elijah A , Shah Sahil
Published: December 2023

Objective. Spiking neural networks (SNNs) are powerful tools that are well suited for brain machine interfaces (BMI) due to their similarity to biological neural systems and computational efficiency. They have shown comparable accuracy to state-of-the-art methods, but current training methods require large amounts of memory, and they cannot be trained on a continuous input stream without pausing periodically to perform backpropagation. An ideal BMI should be capable training continuously without interruption to minimize disruption to the user and adapt to changing neural environments. Approach. We propose a continuous SNN weight update algorithm that can be trained to perform regression learning with no need for storing past spiking events in memory. As a result, the amount of memory needed for training is constant regardless of the input duration. We evaluate the accuracy of the network on recordings of neural data taken from the premotor cortex of a primate performing reaching tasks. Additionally, we evaluate the SNN in a simulated closed loop environment and observe its ability to adapt to sudden changes in the input neural structure. Main results. The continuous learning SNN achieves the same peak correlation (

ρ
=
0.7

) as existing SNN training methods when trained offline on real neural data while reducing the total memory usage by 92%. Additionally, it matches state-of-the-art accuracy in a closed loop environment, demonstrates adaptability when subjected to multiple types of neural input disruptions, and is capable of being trained online without any prior offline training. Significance. This work presents a neural decoding algorithm that can be trained rapidly in a closed loop setting. The algorithm increases the speed of acclimating a new user to the system and also can adapt to sudden changes in neural behavior with minimal disruption to the user.
Characterization results of the first small pixel high rate (SPHIRD) pixel detector prototypes
Authors: Magalhaes Debora , Fajardo Pablo , Grybos Pawel , Kleczek Rafal , Kmon Piotr , Otfinowski Piotr , Ruat Marie
Published: December 2023

This work presents a summary of the experimental results and the performance obtained from a first set of p-type silicon SPHIRD prototypes. The SPHIRD project (Small Pixel High Rate photon counting Detector) targets a new generation of X-ray photon counting hybrid pixel detectors for synchrotron radiation applications, with small pixels and operating between 10 and 30 keV. The readout ASIC is designed to explore techniques that boost the count rate capabilities of the detector and methods to manage, or in some cases exploit, the effects of charge sharing that are unavoidable with small pixels in this type of detector.

The achievement of high photon rates relies on the implementation of a fast charge-sensitive amplifier in the pixel

in combination with pile-up compensation techniques, which have been compared experimentally. The obtained results show and quantify their effectiveness in increasing the count-rate handled by the detector.

The readout chip also includes dedicated circuitry for the relocation of photon hits, a functionality necessary to reduce the photon losses that are observed in photon counting detectors due to charge sharing when the discrimination threshold is set to 50% of the photon energy. The circuitry is however not limited to full pixel relocation: it also implements resources to reassign X-ray hits within regions smaller than the physical pixel. All these operation modes were experimentally evaluated with a pencil beam and with full field images.