bluuebunny/crossref_metadata_2025 huggingface dataset:
Unveiling digital dynamics: Do digital media investments impact organic branded searches?
Authors: Filippou Georgios , Georgiadis Athanasios G. , Jha Ashish Kumar
Published: February 2025

This study addresses a fundamental challenge in digital advertising: how performance-focused campaigns, traditionally aimed at lower-funnel activity, may influence brand awareness. With the growth of online advertising, businesses increasingly rely on performance campaigns across social media, search engine marketing and display networks to drive results. However, a notable phenomenon has emerged. Businesses may observe substantial branded search activity, suggesting lower-funnel campaigns could indirectly shape brand awareness. To investigate this relationship, data were analysed from an e-commerce business operating in five European countries with an annual multimillion-euro lower-funnel budget. We employed a ridge regression model with adstock values to account for temporal advertising effects and address common challenges of multicollinearity in multichannel analysis. Our analysis reveals that lower-funnel campaigns significantly drive branded search activity, suggesting they play an unacknowledged role in building brand awareness. The incorporation of adstock values into ridge regression improves model performance, increasing the R
2 from 0.658 to 0.768 and lowering root mean square. This approach stabilizes residual variance and provides a more accurate representation of advertising’s fading effects over time. These findings offer a replicable framework for practitioners to measure the indirect branding effects of performance campaigns and optimise cross-channel investments.
Divided by vaccination? Evaluating the intergroup conflict between pro- and anti-vaccination groups in the post-pandemic era
Authors: Filsinger Maximilian , Freitag Markus
Published: February 2025

The vaccination against COVID-19 has torn societies apart. Against this background we evaluate three interrelated research questions: (1) does vaccination polarize citizens even after the COVID-19 pandemic has faded; (2) do opinions about vaccination correlate with group formation and identification, and (3) do we observe opinion-based affective polarization regarding vaccination in the post-pandemic era? Based on two original surveys from Switzerland in early 2022 and late 2023, our results highlight that respondents have distinct opinions about vaccination, but that only pro-vaccination respondents have formed an opinion identity. We also observe an asymmetric affective polarization: pro-vaccination respondents show higher levels of liking toward other pro-vaccination respondents but significant dislike toward anti-vaccination respondents, while the same does not hold true for anti-vaccination respondents. Overall, affective polarization toward vaccination is less pronounced in the aftermath of the health crisis than during the COVID-19 pandemic. However, at a time when globalization is boosting the threat of pandemics, caution is warranted, as an increasing salience of vaccination could widen the divide again.
Preparing for knowledge co-production: A diagnostic approach to foster reflexivity for interdisciplinary research teams
Authors: Ligtermoet E. , Munera-Roldan C. , Robinson C. , Sushil Z. , Leith P.
Published: February 2025

There is broad recognition of the essential requirement for collaboration and co-producing knowledge in addressing sustainability crises and facilitating societal transitions. While much effort has focused on guiding principles and retrospective analysis, there is less research on equipping researchers with fit-for-context and fit-for-purpose approaches for preparing and implementing engaged research. Drawing on literature in co-production, collaboration and transdisciplinary science, we present an operationalising framework and accompanying approach designed as a reflexive tool to assist research teams embarking in co-production. This framework encourages critical evaluation of the research contexts in which teams are working, examining the interactions between positionality, purpose for co-producing, contextual and stakeholder power, and the tailoring of co-production processes. We tested this diagnostic approach with four interdisciplinary research teams preparing for co-production in sustainability research in Australia’s national science agency, CSIRO. Data collected during and after these applications, indicate that the approach effectively stimulated a greater understanding and application of a critical co-production lens in the research team’s engagement planning. Workshop discussions revealed opportunities for reflexivity were generated across four learning domains; cognitive, epistemic, normative and relational. We argue that fostering opportunities for reflexivity across these learning domains strengthens teams’ abilities to apply a critical co-production lens, in their engagement work. While this approach has been tested only in the initial preparatory phase for research teams, the framework and diagnostic questions are likely applicable to later work with collaborators and could support iterative re-application of the critical lens at important times during or throughout the life of a project.
From predictors and SHAKE toward unified integration scheme for molecular dynamics
Authors: Janek Jiří
Published: February 2025

Molecular dynamics (MD) simulations applied to various special tasks such as thermostats, barostats, external volume control, or external magnetic fields often require tailored integration methods, complicating software development. Here, we propose a unified integration scheme for solving the common sets of equations of motion in MD. To achieve this, we adapted the traditional SHAKE method for treating rigid bonds to a predictor–corrector integration scheme and combined it with the existing time-reversible velocity predictor and box predictor. This new approach enables using both the time-honored Verlet method and the recently improved Gear methods. The resulting unified integration scheme was tested on two simple models and two MD systems: SPC/E water and ionic liquid (1-ethyl-3-methylimidazolium tetrafluoridoborate). Trajectories in microcanonical, Nosé–Hoover canonical, and MTK isobaric ensembles were generated. The results for Verlet-based methods were in excellent agreement with those obtained using conventional integration methods. For particular tasks, the use of higher-order methods can be beneficial. Overall, in comparison with standard approaches, our universal scheme provides a significantly simpler route to devising new integrators and maintaining existing simulation software. Furthermore, our family of new integrators can be efficiently deployed in massively parallel MD software.
Perturbative spin–orbit couplings for the simulation of extended framework materials
Authors: Vogt Jan-Robert , Wilhelm Jan , Hehn Anna-Sophia
Published: February 2025

A comprehensive description of photo-chemical processes in materials, comprising spin-forbidden processes such as intersystem crossing and phosphorescence, implies taking into account spin–orbit coupling. We present an efficient implementation of a perturbative spin–orbit coupling correction for the Tamm–Dancoff approximation of linear-response time-dependent density functional theory within a mixed Gaussian and plane wave framework relying on spin–orbit coupling corrected pseudopotentials. The implementation is validated for a benchmark set of small aromatic molecules, with mean errors in excitation energies and spin–orbit coupling matrix elements being in the range of 0.1–0.6 eV and 1.0–14.4 cm−1, respectively, in comparison with density functional theory and density functional theory multi-reference configuration interaction reference results. Computational timings are given for a bismuth-containing metal–organic framework.
Near ideal photoluminescence in perovskites: Excitonic effects and self-consistent back extraction of recombination parameters
Authors: Nair Pradeep R.
Published: February 2025

Recent reports indicate that perovskite-based light emitting diodes (LEDs) have achieved an external quantum efficiency (EQE) of 32%—rather an internal quantum efficiency close to 100%. Much of this improved performance is attributed to the role of excitons. While the experimental trends are encouraging, the recombination parameters estimated through extensive curve-fitting of photoluminescence transients are often not amenable to reasonable interpretations. In view of the same, through a detailed analysis of free carrier–exciton dynamics in perovskite optoelectronic materials, here we identify a coherent scheme to unambiguously back extract the relevant parameters. The model predictions compare well with the recent experimental results on perovskite LEDs with record EQE, thus quantifying the role of excitons. Importantly, this work identifies a physics aware scheme for the design of experiments tailored toward consistent exploration of underlying physical mechanisms and hence could enable a synergistic optimization of process technology and device performance.
Enhanced AlGaN/GaN ultraviolet phototransistor: Achieving single-pixel imaging and communication
Authors: Zhao Huiqin , Cai Qing , You Haifan , Guo Hui , Hao Lin , Xu Linling , Liu Yushen , Lu Hai , Zheng Youdou , Zhang Rong , Chen Dunjun
Published: February 2025

The ideal combination of high sensitivity and fast response speed is crucial for advanced photodetectors. Herein, we present a normally-off, visible-blind ultraviolet (UV) AlGaN/GaN phototransistor featuring a fluorine-ion-implanted trench gate structure. This design effectively disrupts the conductive channel of the AlGaN/GaN heterostructure, drastically reducing the dark current to the magnitude of 0.1 pA. The trench structure enhances the localized electric field in the confined gate region, significantly improving UV detection sensitivity. Additionally, the finite electric field enhancement induced from fluorine ions (F− ions) accelerates the establishment of photogenerated electron channels. Consequently, the phototransistor exhibits ultrafast response speed, with rise and decay times of 1.5 and 6.7 μs, respectively, along with an exceptional specific detectivity of 3.45 × 1016 cm·Hz1/2 W−1. The detection of weak UV light reaches as low as 76.0 nW/cm2. This remarkable detection capability allows the device to perform high-fidelity single-pixel imaging and facilitates real-time UV communication. The proposed AlGaN/GaN phototransistor, characterized by a straightforward fabrication process and excellent photoresponse performance, presents enticing prospects for multiple performance compatible optoelectronic devices.
Design and performances of intake for atmosphere-breathing electric propulsion systems with the direct simulation Monte Carlo method
Authors: Sannino A. , Pessina V. , Savino R. , Schein J.
Published: February 2025

The design of an effective intake is a critical aspect of atmosphere-breathing electric propulsion development. Using the Direct Simulation Monte Carlo method, the intake collection efficiency, compression ratio, and drag were evaluated and compared across different geometries, including a scaled-down version. Key performance parameters were analyzed over a wide range of Very Low Earth Orbit altitudes (160–240 km), focusing on gas–surface interactions and the impact of inter-particle collisions at lower altitudes. The results derived from the Maxwellian and Cercignani–Lampis–Lord models were compared under various reflection scenarios: fully specular, partially diffuse, and diffuse. The study first examined intake geometries, highlighting how surface curvature affects performance. Further analysis of the best-performing geometry at different altitudes (160–240 km) revealed that neglecting inter-particle collisions at lower altitudes can lead to discrepancies in capture efficiency of up to 40%. This difference diminishes with increasing altitude, becoming negligible. The intake is sized down to a 1:5 ratio to match the dimensions of a CubeSat with no significant effect on compression ratio or capture efficiency, opening up the possibility for nanosatellite applications. Finally, the different gas–surface interaction models provided a range of performance predictions for each analyzed altitude, potentially reflecting the behavior of a real intake operating in the atmosphere. Variations in the mass flow rate supplied to the electric thruster across models offer valuable insights for thruster design.
Vortex-induced vibration features of a flexible pipe with a low mass ratio at subcritical Reynolds numbers
Authors: Cheng Shunzhao , Ren Haojie , Ren Hao , Hu Tengyan , Li Hang , Shi Shengyu , Zhang Mengmeng
Published: February 2025

A new type of riser, such as the thermoplastic composite pipe, features a low mass ratio and is becoming increasingly common in marine engineering projects. However, vortex-induced vibration (VIV) poses a significant concern regarding fatigue damage in risers, and VIV understandings of risers with low mass ratios are still limited and require further investigation. The present study conducted experimental research on a flexible pipe with a critical mass ratio of 0.50 at subcritical Reynolds numbers (Re) through towing in still water. The displacement responses were reconstructed using modal superposition methods. The amplitude, frequency, and phase difference between in-line (IL) flow and cross-flow (CF) directions, motion trajectory, and fatigue damage are analyzed. The results indicate that the unexpectedly larger VIV amplitude with over 1.0 D appears in the IL direction, which is compared to that found in the CF direction. Such higher response amplitude in the IL direction leads to increased fatigue damage. Additionally, the VIVs in both IL and CF directions exhibit no apparent frequency lock-in phenomenon. The frequencies of the VIVs between the IL and CF directions maintain a twice relationship, and the motion trajectory follows a typical “8”-shaped pattern. The present work provides a basic understanding of VIVs in risers with critical mass ratios and offers helpful guidelines for the design of marine risers in engineering applications.
Interfacial hydrodynamics of electrosprays using leaky dielectric fluids
Authors: Biswas Probir , Agarwal Raj M. , Bhushan Braj , Hens Abhiram , Biswas Gautam
Published: February 2025

Electrohydrodynamics (EHD) deals with the motion of a liquid under the influence of an external electric field, and a leaky dielectric fluid has low but non-zero conductivity. Many earlier studies on EHD have considered the flow of perfect dielectric fluids. This study has established a computational framework to investigate the droplet evolution pattern of leaky dielectric fluids under an externally applied electric field. The Navier–Stokes equations and charge conservation equations are solved using the coupled level set and volume of fluid method. It was observed that the dynamics of the leaky dielectric liquid emanating from the orifice of an ejector depends on several factors such as flow rate, electric field intensity, surface tension, Coulombic forces, and electrophoretic forces. Different jetting regimes, such as choked jets, pulsating jets, steady cone jets, and multi jets, were observed based on these conditions. Variations in the drop diameters and jet breakup length at different flow rates were studied, and the results were compared with the available experimental results. It was also observed that the breakup time and detached drop volume can be suitably tuned by varying the strength of the applied electric field.
Aerobic granular sludge treating tannery wastewater and particle size control
Authors: Xu Dong , Wu Shuangxia , Li Zhaoxian , Wu Shuyun , Xu Jiancai , Gu Chaoguang
Published: February 2025

Aerobic granulation of tannery wastewater was successfully accomplished in sequencing batch reactors, with R1 employing a conventional aeration head and R2 utilizing a spiky-type aeration head. The brief settling time of five minutes, along with the influent’s high concentrations of elements such as calcium, magnesium, phosphorus, and iron, were critical factors influencing the formation of aerobic granules. The findings indicated that granules were successfully cultivated in reactors R1 and R2 by day 36 and day 40, respectively. By the 60th day of operation, the mean particle sizes for R1 and R2 were 469.6 ± 31.4 and 390.3 ± 22.8 μm, respectively, with corresponding SVI5 values of 43.6 and 46.2 ml/g. The implementation of a spiky-type aeration head proved effective in mitigating the increase in particle size by continuously shearing the granular sludge. During the entire granulation process, both systems demonstrated enhanced pollutant degradation capabilities, achieving removal efficiencies of ∼85% for COD, 80% for NH4+–N, 70% for TN, and 60% for TP after 60 days of operation. Notable alterations were observed in extracellular polymeric substances and microbial communities, with a substantial increase in the relative abundance of Proteobacteria, rising from 46.45% in the inoculum sludge to 80.98% in R1 and 75.86% in R2. This increase played a pivotal role in the granulation process.
Managed pressure drilling and automated well killing based on African vulture optimization-proportional integral derivative controller
Authors: Yang Hongwei , Long Zhenyu , Li Jun , Zhang Geng , Chen Wang , Zhan Jiahao , Guan Lichen , Wang Biao , Weng Chengkai
Published: February 2025

Both managed pressure drilling (MPD) and kill procedures depend on the rapid and precise control of the choke under varying conditions. To enhance drilling safety and automate MPD and well kill operations, we employed the African vulture optimization algorithm, a proportional integral derivative controller, and an automated choke control panel for automated choke management. Laboratory and offshore platform experiments were conducted to simulate MPD and kill procedures under single-phase and two-phase flow conditions. Additionally, a reliability analysis was performed using fault tree analysis and dynamic Bayesian network to ensure system safety during long-term operations. Experimental results indicate that during the simulated MPD process, the automated system improved choke adjustment efficiency by 19.6% compared to manual control and reduced pressure fluctuations post-stabilization by 60.0%. In the simulated kill procedure, the system effectively tracked the planned pressure curve and exhibited strong anti-interference capabilities. Offshore platform experiments demonstrated a 25.5% increase in choke adjustment efficiency over engineer-operated controls. Pressure fluctuations in simulated MPD and well kill experiments were reduced by 90.7% and 87.0%, respectively, compared to manual operations. Reliability analysis revealed that after one year of continuous operation, the system's failure probability was 22.9%. However, with timely maintenance, the failure probability initially increased but eventually stabilized at 2.8%. In conclusion, the automated choke control system effectively and safely executes MPD and kill procedures, supports engineers in their operations, and significantly enhances drilling safety.
High-frequency/high-field electron paramagnetic resonance generalized spectroscopic ellipsometry characterization of Cr3+ in
β
-Ga2O3
Authors: Rindert Viktor , Galazka Zbigniew , Schubert Mathias , Darakchieva Vanya
Published: February 2025

Electron paramagnetic resonance of Cr3+ ions in β-Ga2O3 is investigated using terahertz spectroscopic ellipsometry under magnetic field sweeping, a technique that enables the polarization resolving capabilities of ellipsometry for magnetic resonance measurements. We employed a single-crystal chromium-doped β-Ga2O3 sample, grown by the Czochralski method, and performed ellipsometry measurements at magnetic field strengths ranging from 2 to 8 T, at frequencies from 82 to 125 and 190 to 230 GHz, and at a temperature of 15 K. Analysis of the frequency-field diagrams derived from all Mueller matrix elements allowed us to differentiate between the effects of electron spin Zeeman splitting and zero-field splitting and to accurately determine the anisotropic Zeeman splitting g-tensor and the zero-field splitting parameters. Our results confirm that Cr3+ ions predominantly substitute into octahedral gallium sites. Line shape analysis of Mueller matrix element spectra using the Bloch–Brillouin model provides the spin volume concentration of Cr3+ sites, showing very good agreement with results from chemical analysis by inductively coupled plasma-optical emission spectroscopy and suggesting minimal occupation of sites with inactive electron paramagnetic resonance. This study enhances our understanding of the magnetic and electronic properties of chromium-doped β-Ga2O3 and demonstrates the effectiveness of high-frequency/high-field electron paramagnetic resonance generalized spectroscopic ellipsometry for characterizing defects in ultrawide-bandgap semiconductors.
Load characteristics of large-scale underwater explosion bubble pair near a wall using the smoothed particle hydrodynamics method
Authors: Fang Xiang-Li , Wang Ping-Ping , Meng Zi-Fei , Ming Fu-Ren , Chen Hao
Published: February 2025

The two-bubble coupling dynamics near a boundary is always complicated due to the inter-bubble interaction and the boundary effect, and relevant research is still very limited. Benefit from the Lagrangian properties, smoothed particle hydrodynamics (SPH) has distinct superiority in handling the bubble fusion, tearing, and fragmentation. Using the SPH method, this work numerically simulates the nonlinear interactions of two large-scale underwater explosion bubbles near an upper wall and investigates the shock characteristics of the bubble pair. Given the superiority of Riemann solvers to handle discontinuities, an accurate multiphase Riemann-SPH method with the monotone upwind-centered scheme for conservation laws reconstruction is adopted. Through this method, the experiment of an out-of-phase bubble pair interaction near the wall is first modeled, and the reliability of the present model is proven by the comparison of the experimental data with the SPH results. Subsequently, the influence of several key factors, including the distance between the bubble pair (γbb), the distance from the bubble to the wall (γbw), and the phase difference of two bubbles (θ), on the dynamic bubble behavior, the jet mode, and the load characteristics are systematically discussed. In this study, four bubble jet patterns are discovered, namely, “merging-upward jet,” “merging-downward jet,” “upward-downward jet,” and “upward-counter jet.” Compared to the cases of θ = 0 and θ = 0.5, the bubble pair under θ = −0.5 always exerts a stronger impact on the wall regarding the pressure peak and impulse, with the upward-downward jet mode posing the greatest load to the wall.
Effects of residual feed intake on the growth performance, carcass traits, meat quality, and serum biochemical parameters of Cherry Valley ducks
Authors: Wang Zhicheng , Zhu Chunhong , Wang Yifei , Liu Hongxiang , Song Weitao , Tao Zhiyun , Xu Wenjuan , Gu Haotian , Zhang Shuangjie , Li Huifang
Published: February 2025

Context Residual feed intake (RFI) is an important indicator for feed efficiency (FE) in poultry nutrition. Aims The present study assessed the impact of RFI on the growth performance, carcass traits, meat quality, and blood biochemical parameters of Cherry Valley ducks. Methods One thousand healthy male ducks at the age of 14 days were housed in individual cages until slaughter at the age of 42 days. The carcass yield, meat quality, and blood biochemical parameters of 40 ducks with the highest RFI (HRFI) and 40 ducks with the lowest RFI (LRFI) were determined. Key results For growth performance, RFI, feed conversion ratio (FCR), and average daily feed intake (ADFI) were considerably lower in the LRFI group than in the HRFI group, whereas no significant differences were observed in bodyweight (BW) or bodyweight gain (BWG). In terms of carcass traits and meat quality, the LRFI group had lower abdominal fat content and shear force, and a higher L* value, whereas there were no remarkable differences in other carcass and meat-quality traits between the two groups. For serum biochemical parameters, serum concentrations of cholecystokinin (CCK) and adrenocorticotropic hormone (ACTH) were significantly higher and total cholesterol (TC) and insulin (INS) concentrations were significantly lower in the LRFI group than in the HFRI group. Conclusions These outcomes suggest that choosing Cherry Valley ducks according to low RFI can enhance FE and some serum biochemical indices, without affecting their production performance, and it can reduce abdominal fat content. Implications Our results showed that RFI is a useful tool for breeders to select more efficient ducks for breeding. Future research should focus on exploring how genetic improvements could lead to lower RFI values in ducks, which could enhance the sustainability of the poultry industry.
Control of core-shell nanoparticles properties through plasma synthesis: a computational study
Authors: Gui Yifan , Lanham Eve , Kushner Mark J
Published: February 2025

The improved properties of core-shell nanoparticles (CSNPs) over homogeneous nanoparticles (NPs) have expanded and diversified the applications of these nanomaterials. However, controlling the properties of CSNPs can be a challenging task. Low temperature plasmas (LTPs) have proven to be an effective method of producing NPs with uniform size and morphology, and high yield. That said, NP transport and growth dynamics are sensitive to LTP properties. We report on a computational investigation of the evolution of Ge-Si CSNP properties as a function of operating conditions through the modeling of a flowing, two-zone inductively coupled plasma (ICP) reactor. Ar/GeH4 and Ar/SiH4 gas mixtures were supplied to separate plasma zones at a pressure of 1 Torr to promote growth of Ge cores and Si shells. The negatively charged CSNPs are trapped electrostatically in the vicinity of the antennas where the plasma is generated and where the majority of particle growth occurs. Particles that grow to a critical size are then de-trapped by fluid drag due to neutral gas flow. A two-dimensional hybrid plasma model coupled with a three-dimensional kinetic NP transport model were utilized to resolve plasma chemistry and NP growth processes that take place on distinct timescales. The trends in CSNP properties and trapping mechanisms associated with flow rate, applied ICP power and inlet precursor fraction are discussed. While the spatial distribution of plasma produced radical species can have significant impact on the NP growth process, the NP transport dynamics are what ultimately dictates the growth environment that is unique to each particle and so determines their final dimension and composition. The key to optimizing reactor conditions involves controlling the spatial density of growth species and plasma profile as a means to tailor particle trapping dynamics suitable to produce CSNPs for a specific application.
Semiconductor-to-metal transition in 2D ferroelectric In2Se3/Te heterobilayers: applications for non‐volatile memory devices
Authors: Ma Zhuang , LI Jitao , Song HongQuan , Wang Yujie , Ma Huizhong , Zhu Hongxia , Xu Yiguo , Wang Wenjie , Heng Yu , Wang Gui
Published: February 2025

Realizing the flexible control of 2D semiconductor-metal transition is a crucial challenge in non‐volatile memory devices. In this study, based on first-principles calculations and the nonequilibrium Green function formalism, we systematically investigated the stability, electronic structures, and transport properties of 2D ferroelectric In2Se3/Te heterobilayers. Our simulations indicate that the excellent thermal and dynamic stability of these heterobilayers. Moreover, the semiconductor to metal transition in In2Se3/Te can be flexibly controlled by modulating the ferroelectric polarization, enabling nonvolatile electrical manipulation of the transition in In2Se3/Te heterobilayers. Finally, the current-voltage (IV) curves of In2Se3/Te-based ferroelectric tunnel junction are examined by using the quantum transport simulations. Specifically, the In2Se3/Te-based junction exhibit an ultrahigh current on/off ratio of up to 3.89"×" 1011. This work provides the feasibility for the design of non‐volatile memory devices through ferroelectric polarization switching.
Ab initio calculations of pressure and temperature dependent elastic constants of lead
Authors: Jacquelin Camille , Jaupart Etienne , Dubois Vincent , Riﬀet Vanessa , Legrand Philippe , Pillon Laurianne Pillon
Published: February 2025

In the framework of DFT, we present a methodology that is as ab initio as possible for calculating the elastic constants in pressure and temperature. In this context, elastic constants are derived via the strain-ﬂuctuation formalism involving Born, kinetic and stress ﬂuctuation terms. AIMD trajectories in the isokinetic (NVT) ensemble are performed using the Abinit software to evaluate each term. Stress ﬂuctuations are obtained directly from the trajectories. The Born term, on the other hand, is obtained by extracting several uncorrelated conﬁgurations from the trajectories and applying the energy-strain method. Bayesian inference is used to quantify the uncertainties associated with this procedure. As a result, the methodology enables elastic constants and their uncertainties to be evaluated for a wide range of materials. Admittedly, the whole approach has a high computational cost. In this paper, the method is then applied to solid lead in the fcc and hcp phases at various pressures and temperatures. The elastic constants obtained are linear as a function of temperature and pressure, and are qualitatively consistent with the experimental results available for the fcc phase. The major computational eﬀort involved in obtaining a numerical ab initio reference database for lead can be used to test the accuracy of other approaches using surrogate models.
A Novel Fault Exclusion Algorithm for Kalman Filter-Based RAIM with GPS and NavIC for Aircraft Navigation
Authors: Bhattacharyya Susmita
Published: February 2025

In recent years, there has been growing interest in Kalman filter (KF)-based integrity monitoring. In this context, a novel fault exclusion (FE) algorithm is developed in this paper for aviation applications, extending prior work on receiver autonomous integrity monitoring for Global Navigation Satellite Systems. Schmidt KF (SKF) is used as a navigation filter to account for time-correlated measurement errors. The presented approach first reduces the computational load of existing work by suitably modifying the fault detection method with nominal changes in performance. Then, it designs an FE methodology, building on the fault detection tests with the SKF. Following the FE, the SKF is appropriately re-initialized, thereby precluding past faults from corrupting the current estimate. Re-initialization is achieved without implementing multiple filters, unlike existing strategies in the literature. Protection levels (PL) are calculated to bound the position errors in the presence of undetected faults. The FE performance is studied in detail using Global Positioning System and Navigation with Indian Constellation signals simulated for an aircraft trajectory. Step, ramp and sinusoidal faults are introduced into multiple satellites at different time instants. The algorithm is shown to hold promise for successfully excluding faults. In only two of more than 50 failure scenarios, a 5 m step fault is not excluded, but the position errors remain bounded by the respective PLs. The new method also offers better performance than that of a conventional algorithm in the presence of ramp and sinusoidal faults. This is particularly important because position errors are unacceptable (i.e. oscillate or grow with time) as some of these faults are not excluded by the conventional approach, resulting in hazardous situations.
The SiP nanotubes as potential metal-free photocatalyst: a density functional theory study
Authors: Wang Chao , Hui Xuan , Zhu Yingtao , Zhao Huanyu , Cao Weijun
Published: February 2025

Hydrogen generation via photocatalytic water splitting holds significant potential as a strategy to tackle energy crises and environmental degradation. We investigated the electronic and photocatalytic properties of SiP single-walled nanotubes as potential photocatalysts employing HSE06 hybrid density functional along with all-electron Gaussian basis sets. Relative to the monolayer, the band gap of nanotube is reduced (e.g., 1.99 eV for (55,0)), and the nature of electron transfer in nanotube changes to direct which can extend the visible light absorption range. Moreover, the hydrogen production rate for SiP (55,0) nanotube increases from 9.97% to 12.41%. Calculations of the band edge positions under various pH conditions indicate that nanotubes exhibit strong reduction capabilities. Within the pH value between 0 and 7 nanotubes with a radius exceeding 40 Å can split water into H2 and O2 simultaneously under sunlight irradiation. Applying tensile and compressible strain can effectively enhance the oxidation ability for overall water splitting due to downward valance band edge. Furthermore, the difference in mobility between the (50,0) nanotube electrons (140.68 cm2 v-1 s-1) and hole (4.26 cm2 v-1 s-1) suggests that electron-hole recombination can be mitigated. Based on the above findings, we hypothesize that SiP nanotubes should be a potential metal-free photocatalyst.
Tungsten control in long pulse operation : feedback from WEST to ITER
Authors: Maget Patrick , Manas Pierre , Morales J , Afonin Kirill , Bourdelle Clarisse , Bucalossi Jerome B , Ciraolo Guido , Coelho Rui , Corre Yann , Dominski Julien , Dumont Remi , Ekedahl Annika , Fedorczak Nicolas , Fonghetti Theo , Gallo Alberto , Gaspar Jonathan , Guillemaut Christophe , Grosjean Alex , Gunn James Paul , Hillairet Julien , Lerche Ernesto , Lunsford Robert , Rivals Nicolas , Silburn Scott Alan , Tsitrone Emmanuelle , Wauters Tom
Published: February 2025

The full W environment that is now foreseen for ITER puts strong emphasis on experimental results obtained in present devices in similar conditions. In this context, the WEST tokamak is well equipped to bring key contributions to the preparation of ITER operation, thanks to its capability to perform long pulses in dominant electron heating, torque-free scheme based on RF systems, and its ITERgrade actively cooled divertor. Recent results of interest cover the understanding of tungsten contamination and the evaluation of conditioning methods, the feedback on the current ramp-up phase, and the ageing of the ITER divertor components in Lmode attached condition. New directions are being explored, in particular low divertor temperature operation that should be the normal operating regime of ITER. We also report on tungsten peaking physics, and the role of light impurity content.
Neural-network based electron density profile inversion for interferometer on EAST tokamak
Authors: Xie Xiaoping , Lan Ting , Liu Haiqing , Zhu Xiang , Mao Wenzhe , Lan Tao , Ding Weixing
Published: February 2025

The Back Propagation Neural Network (BPNN) has been applied to the density inversion problem of the POlarimeter INTerferometer (POINT) system on the EAST tokamak. Using the BPNN, the electron density profile can be directly reconstructed from the line-integrated density measurement provided by the POINT system. The accuracy and reliability of this approach have been investigated through tests on experimental data. Compared to the traditional Park-matrix method, the BPNN-based model demonstrates significantly faster performance and greater robustness against system noise, making it suitable for real-time control of the density profile. Additionally, the influence of various measurement channels on the inverted density profile has been thoroughly analyzed, offering a quantitative approach to optimizing interferometer design for future machines.
q-Breathers in the diatomic β-Fermi-Pasta-Ulam-Tsingou chains
Authors: Deng Lin , Yu Hang , Zhu Zhigang , Fu Weicheng , Wang Yisen , Huang Liang
Published: February 2025

q-Breathers (QBs) represent a quintessential phenomenon of energy localization, manifesting as stable periodic orbits exponentially localized in normal mode space. Their existence can hinder the thermalization process in nonlinear lattices. In this work, we employ the Newton's method to identify QB solutions in the diatomic Fermi-Pasta-Ulam-Tsingou chains and perform a comprehensive analysis of their linear stability. We derive an analytical expression for the instability thresholds of low-frequency QBs, which converges to the known results of monoatomic chains as the bandgap approaches zero. The expression reveals an inverse square relationship between instability thresholds and system size, as well as a quadratic dependence on the mass difference, both of which have been corroborated through extensive numerical simulations. Our results demonstrate that the presence of a bandgap can markedly enhance QB stability, providing a novel theoretical foundation and practical framework for controlling energy transport between modes in complex lattice systems. These results not only expand the applicability of QBs but also offer significant implications for understanding the thermalization dynamics in complex lattice structures, with wide potential applications in related low-dimensional materials.
Bipolarization-controlled metasurfaces for broadband vortex and Airy beam shaping
Authors: Bai Yunting , Wang Yan , Xie Zhiyuan , Li Shaohe , Chen Jian
Published: February 2025

Terahertz (THz) special beams, such as vortex beams and Airy beams with unique field distributions and diffraction characteristics promote the advancements in wireless information transmission. Metasurfaces with subwavelength thickness and tailorable structures provide a versatile platform for generating these exceptional beams. Nevertheless, these generators typically exhibit complex structure, narrow bandwidth, and single-polarity waveform control. Here, we propose a bipolarization-controlled metasurface that can generate desirable circularly polarized (CP) vortex beams and linearly polarized (LP) Airy beams over broadband. The meta-atom is a reflective metal-dielectric-metal structure composed of an 8-shape-liked pattern on the top metal layer. The phase-only modulation and simultaneous amplitude-phase modulation are achieved just by spatially varying the orientation of the top metal layer. As demonstrations, the application of single-order and multi-beam vortices based on Pancharatnam-Berry phase are produced under the illumination of CP waves ranging from 0.96 to 1.75 THz. The full coverage of amplitude-phase are realized for LP waves incidence when the rotation of top metal layer is set from −45° to 45°. On this basis, one-dimensional and two-dimensional Airy beams with quasi-nondiffracting, self-bending, and self-healing properties are validated respectively. The design opens possibilities for application in high-capacity, obstacle-avoidance wireless communication.
Holographic image features of an AdS black hole in Einstein-power-Yang-Mills gravity
Authors: Hu Xin-Yun , He Ke-Jian , Zeng Xiaoxiong
Published: February 2025

By utilizing the AdS/CFT correspondence, we investigate the holographic image of an AdS black hole in Einstein-power-Yang-Mills gravity. The AdS boundary hosts a Gaussian oscillation source, which induces a lensed response on the opposite side of the boundary during propagation through bulk spacetime. The optical system assists observers at the north pole to continuously capture holographic images that show an axisymmetric bright ring known as the Einstein ring. As the observation position shifted, the bright ring gradually transformed into a luminous arc and eventually transitioned into a light point. Simultaneously, we examine the impact of variations in relevant physical quantity on the ring, and present the corresponding brightness curve. The results indicate that as the temperature $T$ and nonlinear Yang Mills charge parameter $q$ increase, the ring radius also increases, while an increase in the chemical potential $u$ leads to a decrease. However, the peak brightness curve of the ring invariably decreases as the values of $T$, $u$, and $q$ increase, albeit to varying degrees. Upon comparing the outcomes of geometric optics, it can be observed that the position of the ring in holography images is consistent with that of the photon sphere. Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Article funded by SCOAP3 and published under licence by Chinese Physical Society and the Institute of High Energy Physics of the Chinese Academy of Science and the Institute of Modern Physics of the Chinese Academy of Sciences and IOP Publishing Ltd.
Optoelectronic memristor based on a-C:Te film for muti-mode reservoir computing
Authors: Tian Qiaoling , Xun Kuo , Li Zhuangzhuang , Zhao Xiaoning , Lin Ya , Tao Ye , Wang Zhongqiang , Ielmini Daniele , Xu Haiyang , Liu Yichun
Published: February 2025

Optoelectronic memristor is generating growing research interest for high efficient computing and sensing-memory applications. In this work, an optoelectronic memristor with Au/a-C:Te/Pt structure is developed. Synaptic functions, i.e., excitatory post-synaptic current and pair-pulse facilitation are successfully mimicked with the memristor under electrical and optical stimulations. More importantly, the device exhibited distinguishable response currents by adjusting 4-bit input electrical/optical signals. A multi-mode reservoir computing (RC) system is constructed with the optoelectronic memristors to emulate human tactile-visual fusion recognition and an accuracy of 98.7% is achieved. The optoelectronic memristor provides potential for developing multi-mode RC system.
Preparation and properties of porous carbon-supported cobalt phosphide materials
Authors: Jin Yingjie , Li Dongli , Liu Yanchi , Fu Yabo , Shi Jiazi , Wei Jiaqi
Published: February 2025

In this study, the porous carbon obtained after carbonization of ZIF-67 was employed as the precursor, and three kinds of porous carbon-supported cobalt phosphide materials (CoP@C-600, CoP@C-700, and CoP@C-800) were obtained after phosphidation. The catalysts were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and their electrochemical catalytic performance was tested via an electrochemical workstation. The relationship between the microstructure and the catalytic activity for hydrogen evolution reaction (HER) was investigated. The CoP@C materials prepared under different conditions all retained the dodecahedral structure of ZIF-67. Moreover, compared to Co@C materials, the transition metal phosphides CoP@C exhibited superior electrocatalytic hydrogen evolution performance. Among them, when the current was -10 mA/cm−2, the overpotential of the CoP@C-600 material was -0.25 V, and its catalytic activity was higher than the other CoP@C materials.
Timepix4 spatial response characterization with X-ray monochromatic synchrotron beam
Authors: Delogu P. , Biesuz N.V. , Bolzonella R. , Brombal L. , Brun F. , Cardarelli P. , Cavallini V. , Feruglio A. , Fiorini M. , Longo R. , Rosso V.
Published: February 2025

The Timepix4 is a readout ASIC developed by the Medipix4 collaboration, designed to work with various semiconductor sensors to form detection systems with 448×512 pixels with a pitch of 55 µm. Its ability to simultaneously measure the Time of Arrival (ToA) and the Time over Threshold (ToT) of the signal makes it particularly suitable for spectral imaging applications. The ToT allows to measure the hit's energy, while the ToA enables to cluster the acquired events, recomposing the signal of the detected photons. The ability to cluster events allows to limit the degradation of the detector's spatial response caused by charge sharing effects, a common issue that affect conventional single-photon-counting detectors. This work aims to characterize the spatial response of a Timepix4-based detection system, in terms of the Edge Spread Function (ESF) and Line Spread Function (LSF), using a monochromatic X-ray beam. The characterization was performed at different energies (10 keV and 20 keV) using the moving edge method; different clustering methods were applied and compared during the analysis.
Exhaled Volatile Organic Compounds Associated with Chronic Obstructive Pulmonary Disease Exacerbations – A Systematic Review and Validation
Authors: van Poelgeest Jorrit , Shahbazi Khamas Shahriyar , Hallawa Ahmed , D'Alessandro Cristian Carlos , Ferreira Ricardo , Maitland van der Zee Anke-Hilse , Brinkman Paul
Published: February 2025

Rationale: Chronic obstructive pulmonary disease (COPD) exacerbations significantly contribute to disease progression, hospitalizations, and decreased quality of life. Early detection of exacerbations through non-invasive methods, such as exhaled volatile organic compounds (VOCs), could enable timely interventions. This study aimed to identify and validate candidate VOC biomarkers that are associated with exacerbations and stable phases of COPD, and could contribute to the development of a breath-based monitoring device.Methods: A systematic review was conducted to identify VOCs associated with COPD and exacerbations. VOCs were selected as candidate biomarkers if they were reported in at least two studies by different research groups. These VOCs were then validated using longitudinal exhaled breath data from the TEXACOLD study, where exhaled breath samples were collected at baseline, during exacerbation, and at follow-up in 14 COPD patients. Sparse Partial Least Squares-Discriminant Analysis (sPLS-DA) was applied to differentiate between samples collected during exacerbation and those at stable phases. Diagnostic accuracy was assessed using Receiver Operating Characteristic (ROC) curves.Results: The systematic review identified nine candidate VOCs. Three were excluded from validation because their dataset overlapped with one used in one of the included review studies. Validation confirmed the discriminatory power of a composite model of these six VOCs, achieving an area under the ROC curve of 0.98, a diagnostic accuracy of 94.3% and a sensitivity of 0.97 and a specificity of 0.93.Conclusion: This study demonstrates that exhaled VOCs can differentiate between exacerbations and stable phases in COPD patients. The validated biomarkers hold promise for future clinical applications, particularly in the development of a non-invasive, breath-based monitoring device for early detection and management of COPD exacerbations, potentially reducing hospitalizations and improving patient outcomes.
The influence of different surface textures on tribological property for cylinder liner-piston ring during running-in
Authors: Kang Jianxiong , Liu Rui , Lü Yanjun , Yang Haoran , Yan Changfeng , Liu Cheng
Published: February 2025

To investigate the tribological performance of honed cylinder liner and coated piston ring during running-in period under the synergistic effect of surface texture, different surface textures were designed on the cylinder liner and piston ring. The coefficient of friction and worn surfaces were measured using the friction and wear tester and a confocal microscope, respectively, and the contact performances were compared with no-textured surfaces. The research results indicate that: when different textures are designed on the piston ring, the square texture exhibits better tribological performance, and the coefficient of friction is reduced by approximately 7.5% compared to the non-textured surface. When surface textures are designed on both the piston ring and cylinder liner, the frictional properties are superior to those of cases where textures are applied only to the piston ring surface. When the pit textures are designed on the surfaces of piston ring and cylinder liner, the non-Gaussian distribution parameters are reduced by approximately 35%, and the surface roughness parameters are reduced by approximately 15%. In addition, increasing the texture density can improve the tribological performance, but it’s not that the higher the texture density, the better the tribological performance.