bluuebunny/crossref_metadata_2025 huggingface dataset:
Tunneling effect in quantum-dot light-emitting diodes
Authors: Yu Rongmei , Cheng Jinbing , Lu Yingying , Pu Chunying , Wang Ting , Ji Wenyu
Published: January 2025

Charge carrier transportation in semiconductor films is a fundamental but crucial process for the light-emitting diodes. Although there have been many studies on charge transport properties of devices based on traditional inorganic crystals and organic amorphous films, such charge behavior within emerging quantum-dot light-emitting diodes (QLEDs)—which are composed of amorphous nanocrystal films with strong quantum confinement effects—has rarely been discussed. Here, we demonstrate that the tunneling effect really occurs in the hybrid QLEDs with ZnO as the electron-transport layer. By suppressing the thermal effect, a negative differential resistance (NDR) phenomenon is observed by decreasing the working temperature of the QLED low to 150 K. Two types of quantum dots (QDs) with different shell structures (i.e., different tunneling barrier) are used to comparatively examine the tunneling effect. The current density–voltage properties of the QLEDs reveal that the device based on QDs with the sharp core-shell structure (i.e., larger tunneling barrier) exhibits more obvious NDR behavior, which is attributed to the stronger tunneling effect. Our results offer significant insight into the charge dynamics and working mechanism in the QLEDs.
Hydromagnetic effects on steady flow of Casson nanofluid through rotating co-axial cylinders
Authors: Maurya Deepak Kumar , Sharma Vikas Kumar
Published: January 2025

In the proposed mathematical model, we have examined hydromagnetic effects on the steady flow of Casson nanofluid through two co-axial horizontal rotating cylinders. The inner and outer cylinders are revolving about their axes with different angular velocity. Using Schauder's fixed point theorem, the existence of a solution to the differential equation has been demonstrated. The expression for the velocity profile involves the modified Bessel functions of first and second kinds. Special cases on velocity profile are obtained for the limiting value of permeability parameter, Casson parameter, Hartmann number, and ratio of angular velocity, respectively. Graphs of velocity profile are plotted for different values of permeability parameter, Casson parameter, aspect ratio, Hartmann number, ratio of angular velocity, and their graphical behaviors are also discussed. It is observed from graphical data that the velocity of Casson nanofluid increases when the permeability parameter, the aspect ratio of radii, or the ratio of angular velocity increases and decreases when either the Casson fluid parameter or the Hartmann number increases.
Flame structure reconstruction in a supersonic combustor based on lightweight contextual encoding coordinate attention network
Authors: An Bangzhuo , Deng Jiawen , Yang Maotao , Tian Ye , Zhang Hua
Published: January 2025

Accurately predicting flame structure in scramjet combustors is crucial for efficient combustion and flow control in supersonic vehicles. In this study, we conducted experiments on flame structure evolution in a supersonic combustor under a 2.5 Mach inflow condition. We collected a dataset containing flame field evolution images and combustor wall pressure data. To reconstruct the flame structure, we proposed contextual encoding coordinate attention network (CECAN), a novel approach utilizing only wall pressure data. We compared CECAN's reconstruction performance with multi-view domain adaptive generative network (MV-DAGN) and ResNet16 models using evaluation criteria over short and long time spans. CECAN demonstrated superior accuracy and stability in reconstructing dynamic flame field evolution images. In the independent test set, CECAN achieved significant improvements compared to the other models, with up to 41.8% enhancement in signal-to-noise ratio, 45.69% enhancement in structural similarity, and 14.24% enhancement in the correlation coefficient. Notably, CECAN is lightweight, with a reduction of 97.54% in volume and 99.53% in computational parameters compared to MV-DAGN. Despite its efficiency, CECAN maintains a balanced performance in computational speed and accuracy. Our findings demonstrate the effectiveness and efficiency of CECAN in reconstructing flame field evolution images. Its superior performance and lightweight nature make it a promising approach for accurate flame structure prediction in scramjet combustors.
Enhanced Fourier modal analysis for water-wave diffractions induced by submerged periodic blocks with arbitrary cross sections
Authors: Wang Jiyong , Chung Fei Fang , Ong Muk Chen
Published: January 2025

Analyzing wave diffraction by periodic structures is crucial in fluid dynamics, coastal engineering, and ocean engineering, with applications spanning wave–structure interactions, coastal protection, and wave energy utilization. Conventional numerical methods primarily utilize Green's functions formulated in cylindrical coordinate systems, which are restricted to two-dimensional geometries and are difficult to accommodate sharp corners. In this study, we present a novel numerical approach to investigate the multi-modal wave diffractions induced by three-dimensional periodic planar blocks within Cartesian coordinate systems. We first model wave diffraction for rectangular shapes using Fourier modal analysis and then reconstruct the boundary matching matrix as a classical Thomson–Haskell propagator, leveraging a block symmetry. To address computational challenges at high frequencies and for large block thicknesses, we implement cascaded transmission matrix algorithms, achieving a computational accuracy improvement of approximately 16 digits. Building on these rectangular block models, we extend the approach to periodic planar blocks with arbitrarily shaped cross sections by discretizing the shapes into finite rectangular elements. This robust numerical solver is valuable for the design of coastal breakwaters and ocean wave energy converter arrays.
Opposition control in compressible turbulent flows
Authors: Ahmad Moghees , Baig M. F. , Anwer S. F.
Published: January 2025

Opposition control using out-of-phase, combined spanwise and wall-normal velocities at the walls has been studied. The control aims to establish a virtual wall away from the boundary wall, restricting and hindering momentum transport in respective directions. The study is carried out for flow regimes at bulk Mach numbers Mab = 0.8, 1.5, and 2.5, for bulk Reynolds number Reb = 3000. The combined velocity control achieves higher skin friction drag than the solitary wall-normal velocity control. The control application achieves a high drag reduction of over 30% for Mab = 0.8 and 1.5. However, for Mab = 2.5, the drag reduction tapers, signifying the loss of control effectiveness for higher Mab flows. At higher Mab number flows, the turbulent contribution to skin friction decreases significantly while the fixed laminar component increases. The quadrant analysis reveals an overall increase in the sweep events for Mab = 2.5 cases—the increase in sweep results from the channel's mean temperature profile. The high-temperature fluid in the channel core leads to the higher viscosity of the fluid as compared to the lower-viscosity near-wall fluid and assists sweeps toward the walls.
Integrating landscape ecology and fuzzy indicators for sustainable marine and coastal landscape evaluation: a case study in Tongguling National Nature Reserve, Hainan
Authors: Zhang Wenjing
Published: January 2025

Context Tongguling National Nature Reserve in Hainan highlights the ecological significance of marine and coastal ecosystems. However, their sensitivities are often overlooked, emphasising the need for improved evaluation methods to ensure sustainable management. Aims This study aims to develop an advanced evaluation framework that accurately assesses landscape sensitivity in marine and coastal regions, thereby supporting targeted conservation and management strategies in fragile ecosystems. Methods The study employed fuzzy mathematics and the analytic hierarchy process (AHP) to introduce a fuzzy co-ordination evaluation method tailored for marine and coastal environments, utilising fuzzy comprehensive evaluation values and co-ordination degrees as key indicators. Key results When applied to the Tongguling National Nature Reserve in Hainan, the method effectively identified critical areas with heightened ecological sensitivity, including zones vital for maintaining water quality and protecting habitats. The fuzzy co-ordination evaluation indicated moderate to high sensitivity levels, highlighting areas where conservation efforts should be prioritised to mitigate negative effects. Conclusions The marine and coastal landscape evaluation model proposed in this study is robust, providing critical insights for immediate conservation and long-term ecosystem management. Implications The findings establish a basis for future conservation strategies and decision-making within marine reserves, potentially guiding similar evaluations in other coastal regions.
Slower swimming promotes chemotactic encounters between bacteria and small phytoplankton
Authors: Foffi Riccardo , Brumley Douglas R. , Peaudecerf François J. , Stocker Roman , Słomka Jonasz
Published: January 2025

Chemotaxis enables marine bacteria to increase encounters with phytoplankton cells by reducing their search times, provided that bacteria detect noisy chemical gradients around phytoplankton. Gradient detection depends on bacterial phenotypes and phytoplankton size: large phytoplankton produce spatially extended but shallow gradients, whereas small phytoplankton produce steeper but spatially more confined gradients. To date, it has remained unclear how phytoplankton size and bacterial swimming speed affect bacteria’s gradient detection ability and search times for phytoplankton. Here, we compute an upper bound on the increase in bacterial encounter rate with phytoplankton due to chemotaxis over random motility alone. We find that chemotaxis can substantially decrease search times for small phytoplankton, but this advantage is highly sensitive to variations in bacterial phenotypes or phytoplankton leakage rates. By contrast, chemotaxis toward large phytoplankton cells reduces the search time more modestly, but this benefit is more robust to variations in search or environmental parameters. Applying our findings to marine phytoplankton communities, we find that, in productive waters, chemotaxis toward phytoplankton smaller than 2 μm provides little to no benefit, but can decrease average search times for large phytoplankton (∼20 μm) from 2 wk to 2 d, an advantage that is robust to variations and favors bacteria with higher swimming speeds. By contrast, in oligotrophic waters, chemotaxis can reduce search times for picophytoplankton (∼1 μm) up to 10-fold, from a week to half a day, but only for bacteria with low swimming speeds and long sensory timescales. This asymmetry may promote the coexistence of diverse search phenotypes in marine bacterial populations.
An RNase III–processed sRNA coordinates sialic acid metabolism of
Salmonella enterica
during gut colonization
Authors: Chen Ziying , Yang Yaomei , Chen Xiaomin , Bei Cheng , Gao Qian , Chao Yanjie , Wang Chuan
Published: January 2025

Sialic acids derived from colonic mucin glycans are crucial nutrients for enteric bacterial pathogens like
Salmonella
. The uptake and utilization of sialic acid in
Salmonella
depend on coordinated regulons, each activated by specific metabolites at the transcriptional level. However, the mechanisms enabling crosstalk among these regulatory circuits to synchronize gene expression remain poorly understood. Here, we identify ManS, a small noncoding RNA derived from the 3’ UTR of
STM1128
mRNA transcribed from a
Salmonella enterica
–specific genetic locus, as an important posttranscriptional regulator coordinating sialic acid metabolism regulons. ManS is primarily processed by RNase III and, along with its parental transcripts, is specifically activated by N-acetylmannosamine (ManNAc), the initial degradation product of sialic acid. We found that the imperfect stem-loop structure at the 5’ end of ManS allows RNase III to cleave in a noncanonical manner, generating two functional types of ManS with the assistance of RNase E and other RNases: short isoforms with a single seed region that regulate the uptake of N-acetylglucosamine, an essential intermediate in sialic acid metabolism; and long isoforms with an additional seed region that regulate multiple genes involved in central and secondary metabolism. This sophisticated regulation by ManS significantly impacts ManNAc metabolism and
S. enterica
’s competitive behavior during infection. Our findings highlight the role of sRNA in coordinating transcriptional circuits and advance our understanding of RNase III-mediated processing of 3’ UTR-derived sRNAs, underscoring the important role of ManNAc in
Salmonella
adaptation within host environments.
Modeling DNA methyltransferase function to predict epigenetic correlation patterns in healthy and cancer cells
Authors: Tse Ariana Y. , Spakowitz Andrew J.
Published: January 2025

DNA methylation is a crucial epigenetic modification that orchestrates chromatin remodelers that suppress transcription, and aberrations in DNA methylation result in a variety of conditions such as cancers and developmental disorders. While it is understood that methylation occurs at CpG-rich DNA regions, it is less understood how distinct methylation profiles are established within various cell types. In this work, we develop a molecular-transport model that depicts the genomic exploration of DNA methyltransferase within a multiscale DNA environment, incorporating biologically relevant factors like methylation rate and CpG density to predict how patterns are established. Our model predicts DNA methylation-state correlation distributions arising from the transport and kinetic properties that are crucial for the establishment of unique methylation profiles. We model the methylation correlation distributions of nine cancerous human cell types to determine how these properties affect the epigenetic profile. Our theory is capable of recapitulating experimental methylation patterns, suggesting the importance of DNA methyltransferase transport in epigenetic regulation. Through this work, we propose a mechanistic description for the establishment of methylation profiles, capturing the key behavioral characteristics of methyltransferase that lead to aberrant methylation.
The false evidence rate: An approach to frequentist error rate control conditioning on the observed
P
value
Authors: Crouch Daniel J. M.
Published: January 2025

A
P
value is conventionally interpreted either as a) the probability by chance of obtaining more extreme results than those observed or b) a tool for declaring significance at a prespecified level. Both approaches carry difficulties: b) does not allow users to make inferences based on the data in hand, and is not rigorously followed by researchers in practice, while (a) is not meaningful as an error rate. Although
P
values retain an important role, these shortcomings are likely to have contributed significantly to the scientific reproducibility crisis. We introduce the concept of defining long-run frequentist error rates given the observed data, allowing researchers to make accurate and intuitive inferences about the probability of making an error after proposing that the null hypothesis is false. As one approach, we define the false evidence rate (FER) as the probability, under the null hypothesis, of observing a hypothetical future
P
value providing evidence toward the alternative hypothesis suggested by the observed
P
value, which we define as a false positive. FERs are much more conservative than their corresponding
P
values, consistent with studies demonstrating that the latter do not effectively control error rates across the scientific literature. To obtain an FER below 5%, one needs to obtain a
P
value below approximately

5
×

10

−
5

, while a
P
value of 5% corresponds to an FER of about 25%.
Strong adsorption of guanidinium cations to the air–water interface
Authors: Bernal Franky , Dodin Amro , Kyprianou Constantine , Limmer David T. , Saykally Richard J.
Published: January 2025

Combining Deep-UV second harmonic generation spectroscopy with molecular simulations, we confirm and quantify the specific adsorption of guanidinium cations to the air–water interface. Using a Langmuir analysis of measurements at multiple concentrations, we extract the Gibbs free energy of adsorption, finding it larger than typical thermal energies. Molecular simulations clarify the role of polarizability in tuning the thermodynamics of adsorption, and establish the preferential parallel alignment of guanidinium at the air–water interface. As a polyatomic cation, guanidinium represents one of the few examples of a positively charged species to exhibit a propensity for the air-water interface. As such, these results expand on the growing body of work on specific ion adsorption.
Exploring young Chilean learners’ ‘thick’ voices about English language learning
Authors: Tabali Pía , Pinter Annamaria
Published: January 2025

This paper aims to explore the perspectives of Chilean primary school children about their English education. A
hermeneutic approach was adopted in this longitudinal study to foreground the voices of children. Altogether 9 children (between
the ages of 7–9) from two underprivileged schools in Santiago, Chile, participated in the study. The first author spent eight
months in the field teaching and researching at the same time. The research question in this paper aims to address the views of
children about their English learning experiences, and based on these insights, some pedagogical implications are drawn for the
context and beyond. Participatory methods for data collection such as conversations wrapped around information gap activities,
role-play games, drawing tasks and reflection tasks were employed to allow the children to express themselves in a relaxed,
trusting and comfortable environment. The findings reveal that young children are articulate and capable of reflecting on what
they enjoy in their English learning and why. This study highlights the importance of incorporating children’s voices into
pedagogical decisions in English language teaching and learning.
Processing costs in Cantonese-Latin script-mixing
Authors: Tam Janessa Pui Ling , Monahan Philip J. , Helms-Park Rena
Published: January 2025

An emerging trend among young Cantonese speakers is to script-mix morphographic Chinese characters with Latin
graphemes in social media exchanges, uncommon in traditional Chinese contexts. Results of a self-paced reading experiment with
Cantonese speakers are reported to determine whether script-mixing incurs processing costs, and if so, whether these can be
attributed to Inhibitory Control of one of the two scripts or to Dual Activation of both scripts but with slower lexical access
within the non-dominant script. Sentences were presented either entirely in Chinese characters or had one region presented in
Latin graphemes. Processing costs arose only at the switch from Latin graphemes back to Chinese characters, pointing to the
involvement of Inhibitory Control. Further, these costs only appeared in a subset of grammatical categories, potentially
coinciding with parsing uncertainties. As such, a combination of script-mixing and parsing complexities could be seen to result in
processing costs in certain sentential positions.
Adaptive Nesterov momentum method for solving ill-posed inverse problems
Authors: Jin Qinian
Published: January 2025

Nesterov’s acceleration strategy is renowned in speeding up the convergence of gradient-based optimization algorithms and has been crucial in developing fast first order methods for well-posed convex optimization problems. Although Nesterov’s accelerated gradient method has been adapted as an iterative regularization method for solving ill-posed inverse problems, no general convergence theory is available except for some special instances. In this paper, we develop an adaptive Nesterov momentum method for solving ill-posed inverse problems in Banach spaces, where the step-sizes and momentum coefficients are chosen through adaptive procedures with explicit formulas. Additionally, uniform convex regularization functions are incorporated to detect the features of sought solutions. Under standard conditions, we establish the regularization property of our method when terminated by the discrepancy principle. Various numerical experiments demonstrate that our method outperforms the Landweber-type method in terms of the required number of iterations and the computational time.
Emergence and tunability of Fermi-pocket and electronic instabilities in layered Nickelates
Authors: Sheth Alpesh , Lacroix Claudine , Burdin Sébastien
Published: January 2025

Layered Nickelates have gained intensive attention as potential high-temperature superconductors, showing similarities and subtle differences to well-known Cuprates. This study introduces a modelling framework to analyze the tunability of electronic structures by focusing on effective orbitals and additional Fermi pockets, mimicking doping or external pressure qualitatively. It investigates the role of the

3

d

z
2

orbital in interlayer hybridization, which leads to the formation of a second pocket in the Fermi surface. The resulting effective model also predicts specific charge and spin susceptibility in the form of Lindhard susceptibility at wave vector

q

0

=
(
π
,
π
)

, which can be tuned by doping or pressure. These results provide valuable insights into tunable orbital contributions and their influence on potential ordering and electronic instabilities in Layered Nickelates.
Platanus occidentalis L. fruit-derived carbon materials for electrochemical potassium storage
Authors: Hao Jiaxing , Ye Mingyuan , Vijaya Kumar Saroja Ajay Piriya , Liu Liying , Wu Yuhan , Hao Xiaorui , Liu Feng , Fang Yingjiao , Dong Xuejun , Li Laishi , Wu Yusheng , Xu Yang
Published: January 2025

In the post-lithium-ion battery era, potassium-ion batteries (PIBs) have been considered as a promising candidate because of their electrochemical and economic characteristics. However, as an emerging electrochemical storage technology, it is urgent to develop capable anode materials that can be produced at low cost and on a large scale to promote its practical application. Biomass-derived carbon materials as anodes of PIBs exhibit strong competitiveness by their merits of low weight, high stability, non-toxicity, and wide availability. In this work, we employed Platanus occidentalis L. fruits as a precursor to prepare a series of biomass-derived carbon materials by simply adjusting carbonization temperature, and we explored their electrochemical potassium storage capability as anode materials. The optimized sample (annealed at 800 °C) delivered good potassium storage capability (193.3 mAh g−1 at 100 mA g−1 after 100 cycles), cycling stability (80.4 mAh g−1 after 300 cycles at 300 mA g−1), and rate performance (51.2 mAh g−1 at 1000 mA g−1). This work demonstrates a feasible way to utilize biomass waste disposal for emerging sustainable energy storage technologies.
Investigation of trochoidal paths in physics lessons
Authors: Kämpf Lydia , Bauer Jan , Stallmach Frank
Published: January 2025

Using the example of trochoids it is shown how Bruner’s cognitive-psychological model of modes of representations is used to introduce the kinematics and its mathematical description of a complex motion in the introductory phase of physics studies. Enactive (experimental), iconic (simulation) and symbolic (equation) representations of the rolling motion of a wheel are combined to address the different types of learning to gradually introduce the formal description of trochoids.
The joint recognition of multi-MHD instabilities on HL-2A
Authors: Zhu Xiaobo , Yang Zongyu , Xia Fan , He Muwen , Shi Peiwan , Yu Liming , Zhang Yi , Deng Wei , Chen Zhengwei , Xu Zhaohe , Dong Yunbo , Zhong Wulyu
Published: January 2025

In tokamak plasmas, various Magnetohydrodynamic (MHD) instabilities could be driven by free energy, which enhance the plasma’s transportation, leading to a reduction in critical fusion parameters such as temperature and density, and in severe cases, can even cause major plasma disruptions. Accurate identification and active control of MHD is an important technology for maintaining stable operation and improving the parameter performance of fusion reactors in the future, but it is difficult to balance the accuracy, robustness and standard uniformity by traditional methods to recognize MHD instability. This study employs deep learning techniques to learn from 1000 shots manually labeled as three types of MHD instabilities: fishbone mode, long-lived mode, and TM mode, enabling real-time automated recognition of the instabilities. High accuracies of 97.83%, 95.32%, 94.84% are obtained on 200 testing shots, which are measured by area under the receiver-operator characteristic curve (AUC). Data processing methods that conform to the intuition of physics experts, such as short time Fourier transform (STFT), have been retained, and advanced artificial intelligence algorithms such as Resnet have been combined to achieve a high accuracy rate. It also demonstrated the robustness in fully automatic detections over thousands of discharges. Furthermore, this study explores multitask learning techniques. Instead of using three individual neural network to recognize the different instabilities, a joint recognition algorithm is proposed. The joint algorithm shares the encoder of the three networks and use separate decoder branches to output the result of different instabilities. An inspiring outcome is found that the joint algorithm outperforms the individual ones on all of the instability recognition tasks. Implementing multiple MHD recognition tasks jointly can comprehensively improve the model’s performance on each task by sharing related information between intrinsically related tasks. This means that in the future, the model can further develop as more tasks are added, revealing a possible technique routine to build an accurate and comprehensive large-scale model for fusion applications. The method realizes high accuracy, robustness and computational efficiency of MHD instability recognition at the same time, providing a powerful means to support the real-time control of MHD instability in future fusion reactors.
Error field correction in reversed field pinch with feedback stabilization of resistive wall mode
Authors: Saad E A , Brunsell P R
Published: January 2025

A recently developed, model-based linear-quadratic optimal resistive wall mode (RWM) control algorithm is extended in this work to include error field (EF) correction. The EF correction is based on a scheme known in control engineering as disturbance estimation and rejection. The new control algorithm performs real-time EF estimation and feedforward EF compensation in parallel with feedback stabilization. The new RWM control algorithm is implemented and tested in reversed field pinch (RFP) plasma experiments on the EXTRAP T2R device. The EF correction leads to improved performance of the RFP plasma, indicated by lower plasma resistance and sustained, less perturbed intrinsic tearing mode rotation, visible as a reduction of the temporal fluctuations in the mode rotation frequency. The estimated spatial and temporal structure of the EF provides useful information for identification of the EF sources in the EXTRAP T2R device.
Ultra-sensitive flexible piezoresistive pressure sensor for biopressure and tiny force measurements based on tilted micropillar array microstructures
Authors: Su Yue , Chang Yukuan , Xiao Mingke , Wu Jiatao , Zhang Xu , Chen Hongda
Published: January 2025

Flexible pressure sensor can acquire important information during contact with the human body and the external environment, thus shining in various fields such as rehabilitative monitoring, artificial intelligence and touch-on displays. With the development of the fifth generation (5 G) mobile communication technology and the Internet of Things, flexible sensing devices need to be used more in ultra-precision fields, such as biopressure and tiny force detection, which require devices to have higher sensitivity. In this work, an ultra-sensitive flexible piezoresistive pressure sensor is created by embedding multi-walled carbon nanotubes onto a polydimethylsiloxane layer with tilted micropillar array microstructures on its surface. Based on the sensing mechanism of microstructure bending deformation rather than compression deformation, the fabricated device exhibits fascinating properties in terms of ultrahigh sensitivity (1.74 kPa−1), fast response time (<100 ms), low detection limit (5.8 Pa) and excellent cyclic stability. Furthermore, the prepared sensors can meet the sensing needs in a variety of dynamic environments, including real-time artery pulse, airflow, acoustic vibrations, and finger bending, indicating that the sensing devices have enormous potential in human health assessment and diagnosis, and robotic tactile perception. This work provides an innovative approach for the development of highly sensitive sensors required in practical applications.
Observing kinematic anisotropies of the stochastic background with LISA
Authors: Heisenberg Lavinia , Inchauspé Henri , Maibach David
Published: January 2025

We propose a diagnostic tool for future analyses of stochastic gravitational wave
background signals of extra-galactic origin in LISA data. Next-generation gravitational wave
detectors hold the capability to track unresolved gravitational waves bundled into a stochastic
background. This composite background contains cosmological and astrophysical contributions, the
exploration of which offers promising avenues for groundbreaking new insights into very early
universe cosmology as well as late-time structure formation. In this article, we develop a full
end-to-end pipeline for the extraction of extra-galactic signals, based on kinematic anisotropies
arising from the galactic motion, via full-time-domain simulations of LISA's response to the
gravitational wave anisotropic sky. Employing a Markov-Chain-Monte-Carlo map-making scheme,
multipoles up to ℓ=2 are recovered for scale-free spectra in the case of a high
signal-to-noise ratio. We demonstrate that our analysis is consistently beating sample variance
and is robust against statistical and systematic errors. The impact of instrumental noise on the
extraction of kinematic anisotropies is investigated, and we establish a detection threshold of
Ω
GW
≳ 5 × 10-8 in the presence of instrument-induced noise. Potential
avenues for improvement in our methodology are highlighted.
Imprints of PeV cosmic-ray sources on the diffuse gamma-ray emission
Authors: Kaci Samy , Giacinti Gwenael
Published: January 2025

We present our new model for the description of the very high energy Galactic gamma-ray
emission based on a discrete injection of cosmic rays by individual sources. We investigate the
morphology of the very high energy gamma-ray sky, the detectability of cosmic-ray sources and the
clumpiness of the diffuse gamma-ray flux, assuming two different scenarios for cosmic-ray
propagation. Namely, a standard isotropic and homogeneous diffusion process and an isotropic and
inhomogeneous diffusion process. We notably formulate a possible explanation to the small number
of hadronic PeVatrons recently detected by LHAASO. In the case of the inhomogeneous diffusion
process, we constrain the number of hadronic PeVatrons to be small. Finally, we give an argument
that may explain the discrepancy between the interstellar gas density distribution and the very
high energy diffuse gamma-ray flux.
Higher-order topology in twisted multilayer systems: a review
Authors: Hua Chunbo , Xu Dong-Hui
Published: January 2025

In recent years, there has been a surge of interest in higher-order topological phases (HOTPs) across various disciplines within the field of physics. These unique phases are characterized by their ability to harbor topological protected boundary states at lower-dimensional boundaries, a distinguishing feature that sets them apart from conventional topological phases and is attributed to the higher-order bulk-boundary correspondence. Two-dimensional (2D) twisted systems offer an optimal platform for investigating HOTPs, owing to their strong controllability and experimental feasibility. Here, we provide a comprehensive overview of the latest research advancements on HOTPs in 2D twisted multilayer systems. We will mainly review the HOTPs in electronic, magnonic, acoustic, photonic and mechanical twisted systems, and finally provide a perspective of this topic.
A WKB method based on parabolic cylinder function for very-low-frequency sound propagation in deep ocean
Authors: Zhan Jian-Kang , Piao Sheng-Chun , Gong Li-Jia , Yang Dong , Guo Yong-Chao , Zheng Guang-Xue
Published: January 2025

A Wentzel–Kramers–Brillouin (WKB) method is introduced for obtaining a uniform asymptotic solution for underwater sound propagation at very low frequencies in deep ocean. The method utilizes a mode sum and employs the reference functions method to describe the solution to the depth-separated wave equation approximately using parabolic cylinder functions. The conditions for the validity of this approximation are also discussed. Furthermore, a formula that incorporates waveguide effects for the modal group velocity is derived, revealing that boundary effects at very low frequencies can have a significant impact on the propagation characteristics of even low-order normal modes. The present method not only offers improved accuracy compared to the classical WKB approximation and the uniform asymptotic approximation based on Airy functions, but also provides a wider range of depth applicability. Additionally, this method exhibits strong agreement with numerical methods and offers valuable physical insights. Finally, the method is applied to the study of very-low-frequency sound propagation in the South China Sea, leading to sound transmission loss predictions that closely align with experimental observations.
Study on surface-pitted TiN nanoparticles for direct absorption solar collectors
Authors: zhang Heng , Cao Yuchun , Chen Xiaowen , Yang Qihang , Chen Ning , Wu Xiaohu
Published: January 2025

Direct absorption solar collectors use nanofluids to absorb and convert solar radiation. Despite the limitations of the photothermal properties of these nanofluids within the absorption spectrum range, modifying the surface structure of the nanoparticles can broaden their absorption spectrum, thereby significantly improving solar thermal conversion efficiency. This paper utilizes the finite element method to investigate the influence of surface pits on the photothermal properties of plasmonic nanoparticles, considering both material composition and surface micro-nano structures. Based on the findings, a novel TiN nanoparticle is proposed to enhance photothermal performance. This nanoparticle exhibits the lowest average reflectance (0.0145) in the 300-1100 nm wavelength range and the highest light absorption intensity across the solar spectrum, enabling highly efficient solar energy conversion. It not only reduces material costs but also effectively broadens the light absorption spectrum of spherical plasmonic nanoparticles. The distribution of the electric field, magnetic field, and energy field of the nanoparticles indicates that the combination of the "lightning rod" effect and surface plasmon resonance (SPR) significantly enhances both the electric and magnetic fields, thereby increasing the localized heating effect and improving photothermal performance. Additionally, the number and size of the pits have a significant impact on the absorption efficiency (η
abs) of TiN nanoparticles. When the surface of the nanoparticles has 38 pits, η
abs can reach 90%, with the minimum optical penetration depth (h) of the nanofluid being 7 mm and the minimum volume fraction (f
v) being 6.95×10-6. This study demonstrates that nanoparticles with micro-nano structures have immense potential in solar thermal applications, particularly in the field of direct absorption solar collectors.
Coupling correction system on the SKIF light source and TbT diagnostics of linear difference resonance with swing of eigenmodes
Authors: Dorokhova D.V. , Dorokhov V.L. , Nikitin S.A.
Published: January 2025

The coupling correction system of the future SKIF light
source has been optimized with the use of numerical simulation. It
includes 128 BPMs (out of 224), 128 skew-quadrupoles out of 256 in
MBA sections and 32 skew-quadrupoles in dispersion-free
intervals. The system is complementary to the global correction and
is intended to suppress simultaneously vertical dispersion and
linear difference resonance. High efficiency of the EVD-based
correction method has been demonstrated at various numerical
examples. The possibility of determining the width of the linear
difference resonance, which is necessary for such a correction, by
the slope of the ellipses of normal modes is under study. The modes
are resonantly swung and their elliptical shape is reproduced
according to the TbT (turn-by-turn) data of the BPMs. The results of
the corresponding real experiment on VEPP-4M are presented, as well
as the numerical experiment on the swing of eigenmodes on the SKIF.
Insect-inspired passive wing collision recovery in flapping wing microrobots
Authors: Li Zixuan , Cui Long , Wang Hongwei , Zhang Feng , Liu Zhaoming , Wang Geng
Published: January 2025

Flying insects have developed two distinct adaptive strategies to minimize wing damage during collisions. One strategy includes an elastic joint at the leading edge, which is evident in wasps and beetles, while another strategy features an adaptive and deformable leading edge, as seen in bumblebees and honeybees. Inspired by the latter, a novel approach has been developed for improving collision recovery in micro aerial vehicles (MAVs) by mimicking the principle of stiffness anisotropy present in the leading edges of these insects. This study introduces a passive, flexible, folding wing design with adaptive leading edges. The impact of these adaptive folding leading edges on the flight performance of flapping-wing MAVs was systematically evaluated. Variations in lift generation and obstacle-crossing capabilities between rigid wings and adaptive deformable wings were quantified. Additionally, the mechanical stiffness of the wings was assessed to validate their functional effectiveness. The proposed mechanism was incorporated into the wings of a dual-layer flapping-wing robot, which demonstrated successful flight recovery after collision. The experimental results indicate that a robot with a 30 cm wingspan can effectively traverse a gap of 16.2 cm during flight, thereby demonstrating its enhanced ability to overcome collision challenges. These findings underscore the potential of adaptive wing designs in enhancing the resilience and performance of MAVs in dynamic environments.
Multi-decadal stability of water ages and tracer transport in a temperate-humid river basin
Authors: Wang Siyuan , Hrachowitz Markus , Schoups Gerrit , Störiko Anna
Published: January 2025

The temporal dynamics of water ages provide crucial insights into hydrological processes and transport mechanisms, yet there remains a significant gap in quantifying water age variability across different temporal scales. This study utilizes a comprehensive dataset spanning 70 years of hydrological observations and tritium records (1953–2022) with a semi-distributed hydrological model with integrated tracer routing routine based on StorageAge Selection functions SAS, to explore the temporal evolution of water ages in the 4000 km2 Upper Neckar River basin, Germany. Our findings indicate a systematic convergence of the variability of young water fractions and other metrics of water age in riverflow and evaporation towards stable values when averaging over increasing time scales. While at daily scales exhibiting considerable variability with young water fractions in riverflow F
wy,Q ∼ 0.01–0.91 and in evaporation F
wy,E ∼ 0.02–0.75, the variability of F
wy,Q and F
wy,E gradually reduces with increasing averaging time scales and converge to 0.45–0.47 and 0.96–0.97, respectively, between individual decades. Liquid water input (P
L), comprising rainfall and snow melt, emerges as the dominant driver of F
wy,Q across all time scales. In contrast, F
wy,E shows varying controls with time scale: soil moisture content governs daily fluctuations, whereas P
L dominates at the decadal scale. Overall, water ages demonstrate remarkable stability with only minor deviations in response to climatic variability: a 20% fluctuation in average decadal P
L results in only ∼4% variation in F
wy,Q and ∼1% in F
wy,E over the study period. These findings suggest a lack of major long-term dynamics in water ages. Consequently, the results suggest that the physical transport dynamics in the Upper Neckar River basin, and potentially in comparable river basins with similar water age characteristics, can be considered near-stationary over multiple decades.
Large increase in extreme fire weather synchronicity over Europe
Authors: Torres-Vázquez Miguel Ángel , Di Giuseppe Francesca , Moreno-Torreira Alberto , Gincheva Andrina , Jerez Sonia , Turco Marco
Published: January 2025

Synchronous extreme fire weather can significantly increase the probability of fire ignition and spread, posing compounding threats to fire management efforts and potentially overwhelming firefighting capabilities. While substantial evidence indicates that weather conditions conducive to wildfires will likely become more frequent with higher levels of global warming, changes in extreme fire weather synchronicity remain understudied. Here, we quantify the synchronicity of extreme fire weather in Europe by analysing historical data of the Canadian fire weather index (FWI) from 1981 to 2022 and projecting FWI future scenarios with temperature increases from 1 °C to 6 °C and precipitation changes from −40% to +60%. Our results highlight Central Europe (CEU) as a significant hotspot, with synchronicity increases of up to 389%, while the Mediterranean region could see increases up to 66%. These findings emphasize the growing need for enhanced cross-border coordination and proactive fire management strategies to address the rising likelihood of concurrent extreme fire weather conditions in a warming climate.
Evaluating oxide nanoparticle exsolution on A-site deficient PrBaCo2O6-δ electrodes
Authors: Carrillo Alfonso J , Balaguer María , Solís Cecilia , López-García Andrés , Haas Sylvio , Fabuel María , Delgado-Galicia Blanca , Rodriguez Isabelle , Vøllestad Einar , Wachowski Sebastian , Strandbakke Ragnar , Norby Truls , Serra Jose M
Published: January 2025

Nanoparticle exsolution is a powerful technique for functionalizing redox oxides in energy applications, particularly at high temperatures. It shows promise for solid oxide fuel cells and electrolyzers. However, exsolution of other chemistries like metal oxides is not well studied, and the mechanism is poorly understood. This work explores oxide exsolution in PrBa1−x
Co2O6−δ
(x = 0, 0.05, 0.1, 0.15) double perovskites, practiced electrodes in proton ceramic fuel cells and electrolyzers. Oxide exsolution in PrBa1−x
Co2O6−δ
aimed at boosting the electrocatalytic activity and was evaluated by varying intrinsic materials-related properties, viz. A-site deficiency and external parameters (temperature, under fixed time, and pO2 = 10−5 atm conditions). The materials were analyzed with conventional characterization tools and synchrotron-based small-angle x-ray scattering. Unlike metal-nanoparticle exsolution, increasing the A-site deficiency did not enhance the extent of oxide-nanoparticle exsolution, whereas larger nanoparticles were obtained by increasing the exsolution temperature. Combined Raman spectroscopy and electron microscopy analysis revealed that BaCoO3, Co3O4, and amorphous BaCO3 nanoparticles were formed on the surface of the double perovskites after the reductive treatments. The present results demonstrate the complexity of oxide-nanoparticle exsolution in comparison with metal-nanoparticle exsolution. Further materials screening and mechanistic studies are needed to enhance our understanding of this method for functionalizing proton ceramic electrochemical cells (PCEC) electrodes.
Optimized control of direct current mini ultra-high voltage amplifier
Authors: Wiranata Ardi , Hasyim Azzam , Mao Zebing , Thongking Witchuda , Afifah Dini Nur , Muflikhun Muhammad Akhsin
Published: January 2025

Soft robotics has gained much attention due to its simplicity and ease of control. Potential technology in soft robotics includes electrohydrodynamic pumps (EHD) and dielectric elastomer actuators (DEAs). EHD Pump operates by utilizing a strong electric field to break neutral particles into charged particles, which then experience motion due to the Coulomb force generated, allowing for the occurrence of flow. Meanwhile, the DEAs also require high voltage to generate a colombic pressure to create an actuation. Both EHD pumps and DEAs require a high-voltage source that can provide a sufficient electric field to operate optimally. However, the commercially available high-voltage amplifier has a high investment cost. In this study, we aimed to create a computer-controlled mini–ultra high voltage amplifier (mini-UHV). Our mini-UHV can amplify 5 V to 3.7 kV DC voltage. We designed a control system to allow the user to generate any kind of waveform easily. Our system accommodates two waveforms: continuous waveform and square wave signal. For square wave signals, we accommodate several frequency variations and amplitudes. The characteristics of each signal are then observed, including maximum voltage, minimum voltage, rise time, and fall time. We found that the square waveform’s maximum voltage in each frequency is stable at 3.7 kV. We expect our mini-UHV can boost the research in soft electroactive polymer.
An autoencoder for compressing angle-resolved photoemission spectroscopy data
Authors: Ágústsson Steinn Ýmir , Haque Mohammad Ahsanul , Truong Thi Tam , Bianchi Marco , Klyuchnikov Nikita , Mottin Davide , Karras Panagiotis , Hofmann Philip
Published: January 2025

Angle-resolved photoemission spectroscopy (ARPES) is a powerful experimental technique to determine the electronic structure of solids. Advances in light sources for ARPES experiments are currently leading to a vast increase of data acquisition rates and data quantity. On the other hand, access time to the most advanced ARPES instruments remains strictly limited, calling for fast, effective, and on-the-fly data analysis tools to exploit this time. In response to this need, we introduce ARPESNet, a versatile autoencoder network that efficiently summmarises and compresses ARPES datasets. We train ARPESNet on a large and varied dataset of 2-dimensional ARPES data extracted by cutting standard 3-dimensional ARPES datasets along random directions in k. To test the data representation capacity of ARPESNet, we compare k-means clustering quality between data compressed by ARPESNet, data compressed by discrete cosine transform, and raw data, at different noise levels. ARPESNet data excels in clustering quality despite its high compression ratio.