bluuebunny/crossref_metadata_2025 huggingface dataset:
Central limit theorem of overlap for the mean field Ghatak–Sherrington model
Authors: Sheng Yueqi , Wu Qiang
Published: October 2024

The Ghatak–Sherrington spin glass model is a random probability measure defined on the configuration space {0,±1,±2,…,±S}N with system size N and S⩾1 finite. This generalizes the classical Sherrington–Kirkpatrick (SK) model on the boolean cube {−1, +1}N to capture more complex behaviors, including the spontaneous inverse freezing phenomenon. We give a quantitative joint central limit theorem for the overlap and self-overlap array at sufficiently high temperature under arbitrary crystal and external fields. Our proof uses the moment method combined with the cavity approach. Compared to the SK model, the main challenge comes from the non-trivial self-overlap terms that correlate with the standard overlap terms.
Numerical study on effects of leading-edge manufacturing defects on cavitation performance of a full-scale propeller. I. Simulation for the model- and full-scale propellers without defect
Authors: Jin Shanqin , Peng Heather , Qiu Wei
Published: October 2024

Paper I of this two-part paper focuses on predicting the open-water cavitation performance of the model- and full-scale propellers based on the geometry of David Taylor model basin 5168 propeller without leading-edge (LE) defect. Simulations were conducted using the three-dimensional (3D) steady Reynolds-Averaged Navier–Stokes solver in the commercial software package Star-CCM+. Effects of simulation parameters, including domain size, grid size, stretch ratio, first-grid spacing, y+, and turbulence model on the solutions were carefully examined and the best-practice settings for the model propeller and the full-scale propeller with no LE defect were developed. Validation studies were carried out for the propeller model against the experimental data. Results for the full-scale propeller were compared with those of the model-scale propeller. The differences in model and full-scale predictions are generally insignificant. To further confirm this finding, the scale effect was investigated with four additional scale ratios, λ = 2, 3, 4, and 5. The results showed that the scale effect is in general minimal and, therefore, the developed best-practice settings can be applied to the open-water simulation of the full-scale propeller. Paper II presents the simulation for the full-scale propellers with LE defects.
Phase behavior of metastable water from large-scale simulations of a quantitatively accurate model near ambient conditions: The liquid–liquid critical point
Authors: Coronas Luis Enrique , Franzese Giancarlo
Published: October 2024

The molecular mechanisms of water’s unique anomalies are still debated upon. Experimental challenges have led to simulations suggesting a liquid–liquid (LL) phase transition, culminating in the supercooled region’s LL critical point (LLCP). Computational expense, small system sizes, and the reliability of water models often limit these simulations. We adopt the CVF model, which is reliable, transferable, scalable, and efficient across a wide range of temperatures and pressures around ambient conditions. By leveraging the timescale separation between fast hydrogen bonds and slow molecular coordinates, the model allows a thorough exploration of the metastable phase diagram of liquid water. Using advanced numerical techniques to bypass dynamical slowing down, we perform finite-size scaling on larger systems than those used in previous analyses. Our study extrapolates thermodynamic behavior in the infinite-system limit, demonstrating the existence of the LLCP in the 3D Ising universality class in the low-temperature, low-pressure side of the line of temperatures of maximum density, specifically at TC = 186 ± 4 K and PC = 174 ± 14 MPa, at the end of a liquid–liquid phase separation stretching up to ∼200 MPa. These predictions align with recent experimental data and sophisticated models, highlighting that hydrogen bond cooperativity governs the LLCP and the origin of water anomalies. We also observe substantial cooperative fluctuations in the hydrogen bond network at scales larger than 10 nm, even at temperatures relevant to biopreservation. These findings have significant implications for nanotechnology and biophysics, providing new insights into water’s behavior under varied conditions.
A circuit-generated quantum subspace algorithm for the variational quantum eigensolver
Authors: Hirsbrunner Mark R. , Mullinax J. Wayne , Shen Yizhi , Williams-Young David B. , Klymko Katherine , Van Beeumen Roel , Tubman Norm M.
Published: October 2024

Recent research has shown that wavefunction evolution in real and imaginary time can generate quantum subspaces with significant utility for obtaining accurate ground state energies. Inspired by these methods, we propose combining quantum subspace techniques with the variational quantum eigensolver (VQE). In our approach, the parameterized quantum circuit is divided into a series of smaller subcircuits. The sequential application of these subcircuits to an initial state generates a set of wavefunctions that we use as a quantum subspace to obtain high-accuracy groundstate energies. We call this technique the circuit subspace variational quantum eigensolver (CSVQE) algorithm. By benchmarking CSVQE on a range of quantum chemistry problems, we show that it can achieve significant error reduction in the best case compared to conventional VQE, particularly for poorly optimized circuits, greatly improving convergence rates. Furthermore, we demonstrate that when applied to circuits trapped at local minima, CSVQE can produce energies close to the global minimum of the energy landscape, making it a potentially powerful tool for diagnosing local minima.
Tunable THz-whistle built on a two-dimensional electronic analog of a Helmholtz resonator
Authors: Cheremisin M. V.
Published: October 2024

We propose a tunable THz generator built on a two-dimensional electronic analog of a conventional Helmholtz resonator. The generator excitation is provided by a flow similar to that in a whistle in conventional hydrodynamics. The output frequency, hydrodynamic parameters, and practical implementation of the THz-whistle are discussed in relation to possible applications.
Three-dimensional modeling of hydro-morphodynamic characteristics of mining affected alluvial channel using TELEMAC and GAIA
Authors: Mishra Ravi Kumar , Barman Bandita , Pathania Tinesh
Published: October 2024

In this numerical study, TELEMAC-3D and GAIA solvers were coupled to examine the three-dimensional (3D) flow and morphological changes in an alluvial channel due to sand mining. The 3D modeling approach enables a comprehensive analysis of the interactions between bed shear stress, velocity field, secondary flows, and turbulent kinetic energy that affect sediment transport processes near the mining pit. First, the numerical model was applied to two previous experimental studies on straight channels with mining and validated with their published data. Thereafter, model applications are demonstrated to a 180° curved channel with a mining pit at three different locations. The results indicate that the morphological changes in curved channels with a mining pit were relatively more asymmetrical in contrast to straight channels. The most severe bed degradation of 76.8% was observed at the outer bank downstream of the pit located at the end of 180° bend. The analysis of bed shear stress in the curved channel revealed higher values at the outer bank and lower values around the inner bank downstream of the pit location. Additionally, the presence of the mining pit had a significant impact on the structure and location of the secondary flow recirculation cell in the curved channel. The results indicate that turbulent kinetic energy increases significantly in the vicinity of the mining pit in both straight and curved channels. This increased turbulence due to bed topography may account for the enhanced secondary flow and sediment movement observed in the pit region.
An ion soft-landing apparatus for ion transport study with surface potential measurement
Authors: Chen Qiwei , He Liluo , Liu Xianzheng , Zhu Zhen , Bai Yuchen , Zhu Yifan , Liu Jing , Zhou Xiong , Wu Kai
Published: October 2024

An apparatus for explorations of ion transport in a medium and across an interface has been constructed. The ion soft-landing technique is used to deposit low-energy ions onto a pre-adsorbed medium layer on a metal substrate. The designed low-energy ion source can produce a mass-filtered ion beam with tens of nanoampere from solid sources such as bulk metals and salts. The kinetic energy of the ion beam can be lower than 1.0 eV, enabling the ions to be soft-landed onto the medium at the surface. A Kelvin probe with a resolution of less than 32 mV is incorporated to measure the surface potential (SP) variation of the ion-landed sample to monitor the ion transport process in the medium. Temperature-programmed SP measurements on an Ag+-adsorbed ice film prepared on Pt(111) reveal that the temperature threshold for the Ag+-induced SP change of the ice film is about 110 K. The apparatus performance demonstrates its potential in studies of ion transport and related phenomena at both macroscopic and microscopic levels.
The influence of non-Newtonian behaviors of blood on the hemodynamics past a bileaflet mechanical heart valve
Authors: Chauhan A. , Sasmal C.
Published: October 2024

This study employs extensive three-dimensional direct numerical simulations to investigate the hemodynamics around a bileaflet mechanical heart valve. In particular, this study focuses on assessing whether non-Newtonian rheological behaviors of blood, such as shear-thinning and yield stress behaviors, exert an influence on hemodynamics compared to the simplistic Newtonian behavior under both steady inflow and physiologically realistic pulsatile flow conditions. Under steady inflow conditions, the study reveals that blood rheology impacts velocity and pressure field variations, as well as the values of clinically important surface and time-averaged parameters like wall shear stress (WSS) and pressure recovery. Notably, this influence is most pronounced at low Reynolds numbers, gradually diminishing as the Reynolds number increases. For instance, surface-averaged WSS values obtained with the non-Newtonian shear-thinning power-law model exceed those obtained with the Newtonian model. At Re=750, this difference reaches around 67%, reducing to less than 1% at Re=5000. Correspondingly, pressure recovery downstream of the valve leaflets is lower for the shear-thinning blood than the constant viscosity one, with the difference decreasing as the Reynolds number increases. On the other hand, in pulsatile flow conditions, jets formed between the leaflets and the valve housing wall are shorter than steady inflow conditions. Additionally, surface-averaged wall shear stress and blood damage (BD) parameter values are higher (with differences more than 13% and 47%, respectively) during the peak stage of the cardiac cycle, especially for blood exhibiting non-Newtonian yield stress characteristics compared to the shear-thinning or constant viscosity characteristics. Therefore, blood non-Newtonian behaviors, including shear-thinning and yield stress behaviors, exert a considerable influence on the hemodynamics around a mechanical heart valve. All in all, the findings of this study demonstrate the importance of considering non-Newtonian blood behaviors when designing blood-contacting medical devices, such as mechanical heart valves, to enhance functionality and performance.
Origin of unique electronic structures of single-atom alloys unraveled by interpretable deep learning
Authors: Huang Yang , Wang Shih-Han , Achenie Luke E. K. , Choudhary Kamal , Xin Hongliang
Published: October 2024

We uncover the origin of unique electronic structures of single-atom alloys (SAAs) by interpretable deep learning. The approach integrates tight-binding moment theory with graph neural networks to accurately describe the local electronic structure of transition and noble metal sites upon perturbation. We emphasize the complex interplay of interatomic orbital coupling and on-site orbital resonance, which shapes the d-band characteristics of an active site, shedding light on the origin of free-atom-like d-states that are often observed in SAAs involving d10 metal hosts. This theory-infused neural network approach significantly enhances our understanding of the electronic properties of single-site catalytic materials beyond traditional theories.
Combining the generalized quantum master equation approach with quasiclassical mapping Hamiltonian methods to simulate the dynamics of electronic coherences
Authors: Liu Yudan , Mulvihill Ellen , Geva Eitan
Published: October 2024

The generalized quantum master equation (GQME) approach provides a powerful general-purpose framework for simulating the inherently quantum mechanical dynamics of a subset of electronic reduced density matrix elements of interest in complex molecular systems. Previous studies have found that combining the GQME approach with quasiclassical mapping Hamiltonian (QC/MH) methods can dramatically improve the accuracy of electronic populations obtained via those methods. In this paper, we perform a complimentary study of the advantages offered by the GQME approach for simulating the dynamics of electronic coherences, which play a central role in optical spectroscopy, quantum information science, and quantum technology. To this end, we focus on cases where the electronic coherences predicted for the spin-boson benchmark model by direct application of various QC/MH methods are inaccurate. We find that similar to the case of electronic populations, combining the QC/MH methods with the GQME approach can dramatically improve the accuracy of the electronic coherences obtained via those methods. We also provide a comprehensive analysis of how the performance of GQMEs depends on the choice of projection operator and electronic basis and show that the accuracy and feasibility of the GQME approach can benefit from casting the GQME in terms of the eigen-basis of the observable of interest.
On plunging using double-peak kinematics
Authors: El-Salamony Mostafa
Published: October 2024

This study investigates the thrust generation mechanism and performance of a plunging airfoil undergoing double-peak periodic motion, specifically utilizing superposition of the regular sinusoidal waveform with another less-weighted faster one. It is revealed that the proposed waveform produces 200% more thrust when compared to sinusoidal plunging with a small efficiency difference. Also, it produces two vortex pairs (2P) per cycle all over the plunging frequency-amplitude space, instead of the reverse von Karman vortices. Using this proposed waveform, the 2P wake is generated through interaction of three types of vortices shed during plunging, opposing the regular 2P pattern found in the literature.
Prediction of impulse waves generated by partially submerged landslides with a low Froude number based on prototype physical experiments
Authors: Xingchen Dong , Bolin Huang , Qiuwang Li , Shulou Cheng , Yang Li , Guoqiang Yan
Published: October 2024

Impulse waves generated by landslides are a potential threat to reservoirs. Wave prediction formulas that can quickly assess the hazards and extent of landslide-induced waves are an important means for early warning and disaster prevention and mitigation. Partially submerged landslides often generate landslide waves with low Froude numbers. There is limited research on prediction formulas for such waves, and most studies focused on specific wave propagation stages rather than forming a comprehensive formula system. In this study, three typical low Froude number submerged landslides that occurred in the Baihetan reservoir were selected as prototypes, and a large-scale three-dimensional (3D) physical model experiment field with dimensions of 30 × 29.5 × 1.5 m3 was constructed. A total of 95 experiments were performed. The entire process of impulse wave generation in the reservoir area was investigated by dividing the waves into four successive stages: initiation, rapid circular attenuation propagation, progressive attenuation propagation along the channel, and wave run-up. Based on a large amount of physical experimental data, formulas were derived for the maximum wave amplitude, propagation wave amplitude considering the degree of landslide submergence, and impulse wave run-up considering the shore slope orientation and ravine angle. These formulas were combined to form a comprehensive formula system to calculate the whole process of the impulse waves generated by the landslide in the narrow river channel with a wide influence range. The comprehensive formula system was applied to typical representative landslide experiments, and its accuracy was analyzed; the prediction accuracy ranged from 56% to 89.5%. This study can serve as a reference for assessing the risk of impulse waves generated by landslides in reservoir areas.
Propagation and stabilization properties of rotating detonation waves in a hollow combustion chamber with heated air inflow
Authors: Sun Zhipeng , Peng Han , Huang Yue , Gao Sijia , You Yancheng
Published: October 2024

The application of rotating detonation to conventional engine poses challenges such as high-temperature inflow conditions. In this study, experiments were conducted to discuss the propagation and stabilization properties of rotating detonation waves within a hollow rotating detonation combustor using pure heated air/ethylene as propellant. The temperature and equivalence ratio are varied to explore the boundary of detonative limits. The results show that the pressure of detonation waves is influenced by temperature fluctuations, whereas changes in air temperature have minimal impact on velocity losses. In addition to detonation, the deflagration zone is observed within the combustor. When the air temperature is increased, the deflagration zone expands gradually. The static temperature of air increases from 304 to 618 K, resulting in an increase in the area of the glowing zone from 17.7% to 60.0%. The expansion of the zone indicates a rise in deflagration percentage, and a stable single-wave mode is achieved mainly under fuel-rich conditions. The detonative equivalence ratio range is narrowed with increasing heated temperature at 484–618 K. Unstable propagation modes, characterized by sawtooth waves, are frequently observed at detonative lower limit, where the equivalence ratio is around 1.
Proton transfer driven by the fluctuation of water molecules in chitin film
Authors: Matsui Hiroshi , Takebe Yusuke , Takahashi Masae , Ikemoto Yuka , Matsuo Yasumitsu
Published: October 2024

Proton-transfer mechanisms and hydration states were investigated in chitin films possessing the functionality of fuel-cell electrolytes. The absolute hydration number per chitin molecule (N) as a function of relative humidity (RH) was determined from the OH stretching bands of H2O molecules, and the proton conductivity was found to enhance above N = 2 (80%RH). The FIR spectrum at 500–900 cm−1 for 20%RH (N < 1) together with first-principles calculations clearly shows that the w1 site has the same hydration strength as the w2 site. The molecular dynamics simulations for N = 2 demonstrate that H2O molecules with tiny fluctuations are localized on w1 and w2, and the hydrogen-bond (HB) network is formed via the CH2OH group of chitin molecules. Shrinkage of the O–O distance (dOO), which synchronizes with the barrier height, is required for proton transfer from H3O+ to adjacent CH2OH groups or H2O molecules. Nevertheless, dOO is hardly modulated for N = 2 because H2O molecules are strongly constrained on w1 and w2, and therefore, the transfer probability becomes small. For N = 3, novel HBs emerged between the additional H2O molecules broadly distributed on the w3 site and H2O molecules on w1 and w2. The transfer probability is enhanced because large fluctuations and diffusions in the whole H2O molecule yield large modulations of dOO. Consequently, long-range proton hopping is driven by the Zundel-type protonated hydrates in the water network.
Reconciling theories of dominance with the relative rates of adaptive substitution on sex chromosomes and autosomes
Authors: McDonough Yasmine , Ruzicka Filip , Connallon Tim
Published: October 2024

The dominance of beneficial mutations is a key evolutionary parameter affecting the rate and genetic basis of adaptation, yet it is notoriously difficult to estimate. A leading method to infer it is to compare the relative rates of adaptive substitution for X-linked and autosomal genes, which—according to a classic model by Charlesworth et al. (1987)—is a simple function of the dominance of new beneficial mutations. Recent evidence that rates of adaptive substitution are faster for X-linked genes implies, accordingly, that beneficial mutations are usually recessive. However, this conclusion is incompatible with leading theories of dominance, which predict that beneficial mutations tend to be dominant or overdominant with respect to fitness. To address this incompatibility, we use Fisher’s geometric model to predict the distribution of fitness effects of new mutations and the relative rates of positively selected substitution on the X and autosomes. Previous predictions of faster-X theory emerge as a special case of our model in which the phenotypic effects of mutations are small relative to the distance to the phenotypic optimum. But as mutational effects become large relative to the optimum, we observe an elevated tempo of positively selected substitutions on the X relative to the autosomes across a broader range of dominance conditions, including those predicted by theories of dominance. Our results imply that, contrary to previous models, dominant and overdominant beneficial mutations can plausibly generate patterns of faster-X adaptation. We discuss resulting implications for genomic studies of adaptation and inferences of dominance.
Landscape and environmental heterogeneity support coexistence in competitive metacommunities
Authors: Padmanabha Prajwal , Nicoletti Giorgio , Bernardi Davide , Suweis Samir , Azaele Sandro , Rinaldo Andrea , Maritan Amos
Published: October 2024

Metapopulation models have been instrumental in quantifying the ecological impact of landscape structure on the survival of a focal species. However, extensions to multiple species with arbitrary dispersal networks often rely on phenomenological assumptions that inevitably limit their scope. Here, we propose a multilayer network model of competitive dispersing metacommunities to investigate how spatially structured environments impact species coexistence and ecosystem stability. We introduce the concept of landscape-mediated fitness, quantifying how fit a species is in a given environment in terms of colonization and extinction. We show that, when all environments are equivalent, one species excludes all the others—except the marginal case where species fitnesses are in exact trade-off. However, we prove that stable coexistence becomes possible in sufficiently heterogeneous environments by introducing spatial disorder in the model and solving it exactly in the mean-field limit. Crucially, coexistence is supported by the spontaneous localization of species through the emergence of ecological niches. We show that our results remain qualitatively valid in arbitrary dispersal networks, where topological features can improve species coexistence by buffering competition. Finally, we employ our model to study how correlated heterogeneity promotes spatial ecological patterns in realistic terrestrial and riverine landscapes. Our work provides a framework to understand how landscape structure enables coexistence in metacommunities by acting as the substrate for ecological interactions.
The offline roots of online hostility: Adult and childhood administrative records correlate with individual-level hostility on Twitter
Authors: Hebbelstrup Rye Rasmussen Stig , Bor Alexander , Petersen Michael Bang
Published: October 2024

Reducing hostility in social media interactions is a key public concern. Most extant research emphasizes how online contextual factors breed hostility. Here, we take a different perspective and focus on the offline roots of hostility, that is, offline experiences and stable individual-level dispositions. Using a unique dataset of Danish Twitter users (N

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4,931), we merge data from administrative government registries with a behavioral measure of online hostility. We demonstrate that individuals with more aggressive dispositions (as proxied by having many more criminal verdicts) are more hostile in social media conversations. We also find evidence that features of childhood environments predict online hostility. Time spent in foster care is a strong correlate, while other indicators of childhood instability (e.g., the number of moves and divorced parents) are not. Furthermore, people from more resourceful childhood environments—those with better grades in primary school and higher parental socioeconomic status—are more hostile on average, as such people are more politically engaged. These results offer an important reminder that much online hostility is rooted in offline experiences and stable dispositions. They also provide anuanced view of the core group of online aggressors. While these individuals display general antisocial personality tendencies by having many more criminal verdicts, they also come from resourceful backgrounds more often than not.
Cross-chiral exponential amplification of an RNA enzyme
Authors: Cochrane Wesley G. , Bare Grant A. L. , Joyce Gerald F. , Horning David P.
Published: October 2024

An RNA ligase ribozyme that catalyzes the joining of RNA molecules of the opposite chiral handedness was optimized for the ability to synthesize its own enantiomer from two component fragments. The mirror-image D- and L-ligases operate in concert to provide a system for cross-chiral replication, whereby they catalyze each other’s synthesis and undergo mutual amplification at constant temperature, with apparent exponential growth and a doubling time of about 1 h. Neither the D- nor the L-RNA components alone can achieve autocatalytic self-replication. Cross-chiral exponential amplification can be continued indefinitely through a serial-transfer process that provides an ongoing supply of the component D- and L-substrates. Unlike the familiar paradigm of semiconservative nucleic acid replication that relies on Watson–Crick pairing between complementary strands, cross-chiral replication relies on tertiary interactions between structured nucleic acids “across the mirror.” There are few examples, outside of biology, of autocatalytic self-replication systems that undergo exponential amplification and there are no prior examples, in either biological or chemical systems, of cross-chiral replication enabling exponential amplification.
Competing excitation quenching and charge exchange in ultracold Li-Ba+ collisions
Authors: Xing Xiaodong , Weckesser Pascal , Thielemann Fabian , Jónás Tibor , Vexiau Romain , Bouloufa-Maafa Nadia , Luc-Koenig Eliane , Madison Kirk W , Orbán Andrea , Xie Ting , Schaetz Tobias , Dulieu Olivier
Published: October 2024

Hybrid atom-ion systems are a rich and powerful platform for studying chemical reactions, as they feature both excellent control over the electronic state preparation and readout as well as a versatile tunability over the scattering energy, ranging from the few-partial wave regime to the quantum regime. In this work, we make use of these excellent control knobs, and present a joint experimental and theoretical study of the collisions of a single 138Ba+ ion prepared in the

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metastable states with a ground state 6Li gas near quantum degeneracy. We show that in contrast to previously reported atom-ion mixtures, several non-radiative processes, including charge exchange, excitation exchange and quenching, compete with each other due to the inherent complexity of the ion-atom molecular structure. We present a full quantum model based on high-level electronic structure calculations involving spin-orbit couplings. Results are in excellent agreement with observations, highlighting the strong coupling between the internal angular momenta and the mechanical rotation of the colliding pair, which is relevant in any other hybrid system composed of an alkali-metal atom and an alkaline-earth ion.
Magneto-optical Goos–Hänchen shift in uniaxial anisotropic epsilon-near-zero metamaterials
Authors: Sun Yi , Zhang Zan , Zhang Jing , Yang Chenfei , Zhuang Chuhong , Deng Dongmei
Published: October 2024

We theoretically investigate the enhancement of the magneto-optical Goos–Hänchen (MOGH) shift in multilayer structure combining uniaxially anisotropic epsilon-near-zero (ENZ) metamaterials with magneto-optical (MO) materials. The structure enables the excitation of MO surface plasmon resonance (MOSPR) without the need for a prism or grating coupler, thereby achieving a significant enhancement of the MOGH shift. The effect of the thickness of the ENZ layer and the type of magnetic metal in this structure on the MOGH shift is also discussed. Based on the above structure, we design a high-sensitivity miniature biosensor that is used for the detection of hemoglobin concentration in human blood. The maximum sensitivity achievable with this sensor is 1.4 × 106 λ/RIU. The results of this investigation contribute to the development of biosensors towards miniaturization and integration.
Point cloud segmentation method based on an image mask and its application verification
Authors: Cao Jiayong , Liu Chenshu , Liu Hu , Wu Shihao
Published: October 2024

Accurately perceiving three-dimensional (3D) environments or objects is crucial for the advancement of artificial intelligence interaction technologies. Currently, various types of sensors are employed to obtain point cloud data for 3D object detection or segmentation tasks. While this multi-sensor approach provides more precise 3D data than monocular or stereo cameras, it is also more expensive. The advent of RGB-D cameras, which provide both RGB images and depth information, addresses this issue. In this study, we propose a point cloud segmentation method based on image masks. By using an RGB-D camera to capture color and depth images, we generate image masks through object recognition and segmentation. Given the mapping relationship between RGB image pixels and point clouds, these image masks can be further used to extract the point cloud data of the target objects. The experimental results revealed that the average accuracy of target segmentation was 84.78%, which was close to that of PointNet++. Compared with three traditional segmentation algorithms, the accuracy was improved by nearly 23.97%. The running time of our algorithm is reduced by 95.76% compared to the PointNet++ algorithm, which has the longest running time; and by 15.65% compared to the LCCP algorithm, which has the shortest running time among traditional methods. Compared with PointNet++, the segmentation accuracy was improved. This method addressed the issues of low robustness and excessive reliance on manual feature extraction in traditional point cloud segmentation methods, providing valuable support and reference for the accurate segmentation of 3D point clouds.
A novel method: YOLO-CE and 3D point cloud-based feature extraction for welding seams of tower bases
Authors: Pan Haihong , Wang Longyou , Fu Yu , Jia Bingqi , Chen Lin
Published: October 2024

Robotic automated welding of non-standard steel structures presents significant challenges, particularly for electric power tower bases. This study introduces a novel approach that integrates the You Only Look Once—Compact Invert Block and Efficient Local Attention (YOLO-CE) model, an enhanced version of YOLOV8 for 2D image segmentation, with 3D point cloud technology. The YOLO-CE model is used to accurately extract point cloud data from the target area, which is then processed using the MSAC algorithm for efficient plane segmentation. Weld lines are identified through plane equations, allowing for initial weld point cloud extraction. To further refine accuracy, an optimized evaluation equation is developed that accounts for both the distance between the weld point cloud and the fitted plane, and the angle between their normal vectors. This enables precise classification of the weld point cloud. From this classification, key weld feature points are identified, and their exact positions are determined by calculating the distances between these points and their intersections with three planes. The reliability of the proposed method was validated using a robot for precise measurements, with a total error margin of less than 1.5084 mm, demonstrating high accuracy and stability. Post-operation inspections confirmed that the welds were filled and free from defects, meeting all process requirements. The YOLO-CE model achieved a mIoU of 96.38% and a precision of 99.8%, highlighting its effectiveness. This method provides an efficient and precise solution for the automated welding of non-standard steel structural components and has promising application potential.
Compact and simple antenna inspection testing range for 5G smartphones
Authors: Lee Jisu , Kim Jinjoo , Lee Soonyoong , Kim Namkyoung , Jung Kyung-Young
Published: October 2024

Over-the-air antenna performance evaluation in the millimeter-wave band often relies on compact antenna test range systems, which require large reflectors and a substantial measurement range volume. Such setups are impractical for rapid testing in space-constrained environments such as antenna fault diagnosis in smartphone manufacturing facilities. This paper presents a novel design methodology for highly compact antenna inspection testing range utilizing offset parabolic reflectors specifically designed for 5G smartphones. The proposed design system employs three small offset parabolic reflectors configured to account for beam tilting caused by smartphone back covers, eliminating the need to physically reposition the smartphone during testing. By directing electromagnetic fields toward a fixed receiver antenna from multiple angles corresponding to different antenna module positions, the system streamlines the test procedure, significantly reducing measurement time and measurement range volume. The proposed antenna inspection testing range provides a cost-effective and efficient solution for 5G antenna fault diagnosis in manufacturing facilities, ensuring rapid and reliable inspection while minimizing space requirements on the production line.
Size and shape dependence of hydrogen-induced phase transformation and sorption hysteresis in palladium nanoparticles
Authors: Sun Xingsheng , Jin Rong
Published: October 2024

Phase transitions of metals in hydrogen (H) environments are critically important for applications in energy storage, catalysis, and sensing. Nanostructured metallic particles can lead to faster charging and discharging kinetics, increased lifespan, and enhanced catalytic activities. However, establishing a direct causal link between nanoparticle structure and function remains challenging. In this work, we establish a computational framework to explore the atomic configuration of a metal-hydrogen system when in equilibrium with a H environment. This approach combines Diffusive Molecular Dynamics with an iteration strategy, aiming to minimize the system’s free energy and ensure uniform chemical potential across the system that matches that of the H environment. Applying this framework, we investigate H chemical potential-composition isotherms during the hydrogenation and dehydrogenation of palladium nanoparticles, ranging in size from 3.9 nm to 15.6 nm and featuring various shapes including cube, rhombic dodecahedron, octahedron, and sphere. Our findings reveal an abrupt phase transformation in all examined particles during both H loading and unloading processes, accompanied by a distinct hysteresis gap between absorption and desorption chemical potentials. Notably, as particle size increases, absorption chemical potential rises while desorption chemical potential declines, consequently widening the hysteresis gap across all shapes. Regarding shape effects, we observe that, at a given size, cubic particles exhibit the lowest absorption chemical potentials during H loading, whereas octahedral particles demonstrate the highest. Moreover, octahedral particles also exhibit the highest desorption chemical potentials during H unloading. These size and shape effects are elucidated by statistics of atomic volumetric strains resulting from specific facet orientations and inhomogeneous H distributions. Prior to phase transformation in absorption, a H-rich surface shell induces lattice expansion in the H-poor core, while before phase transformation in desorption, surface stress promotes lattice compression in the H-rich core. The magnitude of the volumetric strains correlates well with the size and shape dependence, underlining their pivotal role in the observed phenomena.
Method for measuring the energy transfer upconversion rate of laser crystal for solid-state lasers
Authors: Huang Lei , Pan Wu , Xu Xuesen , Zhang Nana , Liu Ziqi , Chen Shanshan , Yang Huan , Li Renpu , Guo Yongrui
Published: October 2024

A new method for measuring the energy transfer upconversion (ETU) rate of laser crystal for solid-state lasers is provided in this paper. When the ETU effect is considered, the laser’s output power can be expressed in terms of the input power, the ETU rate and the nonradiative lifetime. Multiple sets of binary equations about the ETU rate and the nonradiative lifetime can be obtained by substituting the measured laser input–output powers into the equation of laser output power. By solving the binary equations, the ETU rate and the nonradiative lifetime of the laser crystal can be obtained simultaneously. Employing this method, the measured average values of ETU rate and nonradiative lifetime of the Nd:YLF (Nd3+, 1.0 at.%) crystal are 3.930 × 10−23 m3 s−1 and 6.274 × 10−3 s, respectively. The measured results are further analysed and discussed, showing the feasibility of the method. We believe that the proposed method can offer a good reference for measuring the ETU rate of new laser crystals.
Synthesis of poly (N-isopropylacrylamide)-poly(ε-caprolactone) for temperature-controlled wettability of poly(L-lactic acid)
Authors: Lu Jian , Xia Wenlong , Ye Xiangyang , Song Xiaofeng
Published: October 2024

The biomaterials that can respond to environmental stimuli have attracted increasing attention because their applications will greatly expand the boundaries of modern medicine. In the work, poly(N-isopropylacrylamide)-poly(ε-caprolactone) (PNIPAm-PCL) with the low critical solution temperature (LCST) was synthesized by a combination of chain transfer and ring-opening method to endow poly (lactic acid) (PLLA) with the temperature-controlled wettability. The effects of PNIPAm-PCL on the thermal properties, mechanical properties, and temperature-controlled wettability were studied. At 20 wt% of PNIPAm-PCL/PLLA, the tensile strength of the material reduces slightly, but its elongation at break is enhanced significantly, which reaches 135.1%. PNIPAm-PCL/PLLA exhibits good temperature-controlled wettability. With the temperature rising from 0 to 45 °C, the water contact angle increases from 29.8° to 80.1°; conversely, it goes down, and there is a hysteresis. The material still has good stability and degradability. This work provides an example for the development of intelligent tissue engineering materials.
Shift of plasmon resonance in silver nanoparticles: effect of magnetic field pre-treatment
Authors: Redko Roman , Shvalagin Vitaliy , Milenin Grigorii , Redko Svitlana , Sarikov Andrey
Published: October 2024

A novel magnetic field induced phenomenon in ZnO/Ag nanoparticles is detected and investigated with reference to the surface plasmon resonance (SPR) effect. A shift of the maximum of plasmon absorption of the ZnO/Ag nanoparticles formed in different days in magnetic field treated ZnO/ethanol solutions was observed. The observed phenomena were explained in terms of the ferromagnetic-like properties of the ZnO nanoparticles due to the surface broken bonds, which result in the appearance of non-zero magnetic moments. Magnetic field pre-treatment may be used as an effective tool for manipulating the plasmon properties of silver-based nanoparticles, which is perspective for creating new-generation sensor systems.
Classification of EEG evoked in 2D and 3D virtual reality: traditional machine learning versus deep learning
Authors: Zuo MingLiang , Yu BingBing , Sui Li
Published: October 2024

Backgrounds. Virtual reality (VR) simulates real-life events and scenarios and is widely utilized in education, entertainment, and medicine. VR can be presented in two dimensions (2D) or three dimensions (3D), with 3D VR offering a more realistic and immersive experience. Previous research has shown that electroencephalogram (EEG) profiles induced by 3D VR differ from those of 2D VR in various aspects, including brain rhythm power, activation, and functional connectivity. However, studies focused on classifying EEG in 2D and 3D VR contexts remain limited. Methods. A 56-channel EEG was recorded while visual stimuli were presented in 2D and 3D VR. The recorded EEG signals were classified using two machine learning approaches: traditional machine learning and deep learning. In the traditional approach, features such as power spectral density (PSD) and common spatial patterns (CSP) were extracted, and three classifiers—support vector machines (SVM), K-nearest neighbors (KNN), and random forests (RF)—were used. For the deep learning approach, a specialized convolutional neural network, EEGNet, was employed. The classification performance of these methods was then compared. Results. In terms of accuracy, precision, recall, and F1-score, the deep learning method outperformed traditional machine learning approaches. Specifically, the classification accuracy using the EEGNet deep learning model reached up to 97.86%. Conclusions. EEGNet-based deep learning significantly outperforms conventional machine learning methods in classifying EEG signals induced by 2D and 3D VR. Given EEGNet’s design for EEG-based brain-computer interfaces (BCI), this superior classification performance suggests that it can enhance the application of 3D VR in BCI systems.
Additive manufacturing of multiscale NiFeMn multi-principal element alloys with tailored composition
Authors: Mooraj Shahryar , Fu Jintao , Feng Shuai , K Ng Alexander , Duoss Eric B , Baker Sarah E , Zhu Cheng , Detsi Eric , Chen Wen
Published: October 2024

Nanostructured multi-principal element alloys (MPEAs) have been explored as next-generation engineering materials due to unique mechanical and functional properties which have significant advantages over traditional dilute alloys. However, the practical applications of nanostructured MPEAs are still limited due to the lack of scalable processing approaches to prepare a large quantity of nanostructured MPEAs, as well as lack of an efficient pathway for high-throughput discovery of better functional nanostructured MPEAs within their vast compositional space. Here we tackle these challenges by presenting an integrated approach by combining direct-ink-writing-based additive manufacturing, solid-state sintering, and chemical dealloying to manufacture hierarchically porous MPEAs. The hierarchical structure is comprised of macro- and micro-scale pores introduced via extrusion printing and polymer decomposition during sintering, as well as nanoscale pores formed via chemical dealloying. The macro- and micro-scale pores allow efficient dealloying of a large mass of material as the diffusion length that the corroding medium must penetrate remains at the scale of the ligaments formed after sintering (∼10 μm), despite the large volume of the 3D-printed samples. In addition, this integrated approach enables versatile control of the alloy composition via precisely tuning the ratio of elemental powders in the starting ink, thus offering a pathway for high-throughput discovery of novel functional MPEAs. As a case study, multiscale macro/micro/nanoporous NiFeMn MPEAs with three different compositions were investigated as catalysts to reduce the overpotential of oxygen evolution reaction (OER), where NiFeMn-based electrocatalysts display composition-dependent performance such that the overpotential measured at a current of 0.5 A g−1 for OER increases in the order of Ni58Fe29Mn13 ⩽ Ni64Fe26Mn10 < Ni76Fe18Mn6. This introduced manufacturing process offers new opportunities for scalable fabrication and rapid screening of nanostructured multi-component complex alloys.
Listening Touch
Authors: Smith Rosalind Holgate
Published: October 2024

This chapter investigates foundational practices of listening touch, used in Contact Improvisation, and proposes new touch techniques where space brought into awareness to enhance empathic modes of being with and among Others. Informed by new materialist scholarship concerning the entangled nature of relationships, the author explores touch as a way of being in the world and examines listening as a haptic practice that can make possible encounters with Otherness. Building upon foundational somatic listening practices, the new touch techniques proposed include hovering, accompanying, and listening in action. In these techniques, space is proposed to enhance an individual’s ability to stay with disturbing sensations, strong emotions, arousal, and encounters with the unknown or an Otherness within. Taking from Leah Basel’s essay “The Politics of Listening,” space is considered to enhance empathy and compassion and in this research is applied in touch and embodied in dance to support ethical and sustainable ways of co-becoming with diverse cultures and differences. The author draws from lab group research with CI colleagues that form part of her community in Berlin, and she reflects also on an extended CI practice that involves dancing outdoors with environmental matter. These varied contexts and sources support reflections on how receptively humans can relate with other material life forms, and assist her in developing techniques of listening that suggest deeply embedded, environmental ways of attending with Others on micro and macro terms.
Contact Improvisation in China and Taiwan
Authors: Ku Ming-Shen , Liao Shuyi (Candy) , Zhang Xiao , Ge Huichao (Dew) , Wang Yuting (Elsie)
Published: October 2024

This roundtable discusses the presence and evolution of Contact Improvisation (CI) in mainland China and Taiwan. The participants come from various backgrounds from Beijing, Hangzhou, and Taiwan and share their personal journeys with CI, highlighting its introduction, development, and significance in their dance communities. They reflect on the impact of the COVID-19 pandemic on CI activities and the role of CI in fostering connections, trust, and spirituality in their local communities. In terms of CI’s future in these regions, they express optimism and emphasize its inclusive and open nature. They also stress the importance of overcoming language barriers to facilitate international exchange and understanding within the global CI community. This conversation sheds light on the unique perspectives and contributions of mainland China and Taiwan to the world of Contact Improvisation.