bluuebunny/crossref_metadata_2025 huggingface dataset:
Peculiarities in the phase diagram of (La1–xNdx)3S4 solutions
Authors: Starikov M. A. , Sokolov V. V. , Ikorskii V. N.
Published: January 2025

The superconducting and magnetic phase diagram of (La1–xNdx)3S4 solid solutions are studied in the concentration range from 0 to 15 at. % Nd. Superconductivity is observed right up to 6 at. % Nd, which is in excess of the critical concentration xc = 4 at. % obtained from the Abrikosov–Gor’kov theory. A weaker suppression of superconductivity by the Nd impurity is probably associated with the splitting of the ground state of Nd3+ by the crystal field. Measurements of the magnetic susceptibility show that the splitting between the ground doublet and the excited quartet is 75±3 K. A transition to the ferromagnetic state is observed at concentrations exceeding 6 at. % Nd.
The influence of the Kondo effect on the crystalline electric field in Ce3AI compound
Authors: Vasilkevich A. A. , Ivanitskii P. G. , Slisenko V. I.
Published: January 2025

The energy structure of the principal multiplet 2F5/2 of the Ce3+ ion in Ce3Al is investigated by inelastic neutron scattering (INS). The effect of strong interaction between 4f-electrons and conduction electrons on the crystalline electric field (CEF) is of “antiscreening” nature. This effect leads to an increase in the energy of CEF levels (∼ 30%) upon a decrease in temperature from 300 to 100 K and is accompanied by broadening of inelastic transition lines from 1.5 to 2.2 meV. The presence of two quasi-elastic lines in the INS spectrum of Ce3Al with strongly differing widths (approximately by a factor of nine) indicates the existence of fast and slow Kondo spin fluctuations in this compound.
Elastic vibrations in solids with disclinations
Authors: Natsik V. D. , Smirnov S. N.
Published: January 2025

The method of describing small-amplitude waves in a nonuniformly deformed medium, which is well known in the mechanics of elastic continuum, is generalized to the case of an elastic isotropic medium with Volterra disclinations for which the distortion is a multiple-valued function of spatial coordinates. The Murnagan equation of state is used to obtain an expression for the elastic energy density and dynamic equations describing small vibrations in a medium deformed by elastic disclination fields. The specific case of normal vibrations of a long cylinder containing a wedge disclination whose line coincides with the cylinder axis is considered. The effect of disclination on the family of axisymmetric torsional vibrational modes of the cylinder is studied in detail. The perturbation theory in small parameter, viz., dimensionless disclination strength, is developed and analytic expressions are obtained for the dispersion relation and vibrational states.
Single-photon generation and manipulation in quantum nanophotonics
Authors: Liu Guangxin , Zhou Wenjie , Gromyko Dmitrii , Huang Ding , Dong Zhaogang , Liu Renming , Zhu Juanfeng , Liu Jingfeng , Qiu Cheng-Wei , Wu Lin
Published: January 2025

Developing reliable and efficient single-photon sources is crucial for advancing quantum technologies, relying on nonlinear frequency conversion or spontaneous emission from individual quantum emitters. While different types of single-photon sources excel in specific applications, none meet all criteria for an “ideal” source: exceptional brightness, high purity, and indistinguishability. To address this challenge, coupling single-photon emitters with designer nanostructures can significantly enhance emission performance, a pivotal area in quantum nanophotonics. This review summarizes recent advancements over the past decade in generating and manipulating single photons, emphasizing the pivotal role of nanostructure coupling. Single-photon emission systems—such as nonlinear crystals, solid-state defects, quantum dots, carbon nanotubes, and two-dimensional materials—are categorized quantitatively based on their ability to achieve high purity, indistinguishability, and brightness, presented in a three-dimensional technology map. Furthermore, nanostructure engineering is showcased for manipulating properties such as emission direction, polarization, chirality, and entanglement of single photons. By elucidating these critical aspects, this review aims to advance understanding of how advancements in nanostructured environments promise to shape the future of single-photon generation and manipulation within quantum nanophotonics.
Three-dimensional carbon fiber networks with self-orienting nano-textures enabled by femtosecond laser processing
Authors: Hayashi Shuichiro , Sanchirico Amelia , Das Ankit , Arnold Craig B.
Published: January 2025

Here, an interconnected three-dimensional (3D) network of carbon fibers possessing nano-scaled ripples, or laser-induced periodic surface structures (LIPSS), is fabricated via laser processing with an 800-nm femtosecond laser. The unique architecture of the CF network realizes the coexistence of both ∼800-nm low-spatial frequency LIPSS (LSFL) and ∼100-nm high-spatial frequency LIPSS (HSFL) overlapping on the same fiber surface. It is suggested that LSFL formed through the interference with Fresnel diffraction patterns projected by the fiber edges, while HSFL formed through LSFL-splitting assisted by surface plasmons. Moreover, the fundamentally different formation mechanisms of the two types result in distinctively different LIPSS orientations, where the LSFL is structure-dependent and self-orients according to the fiber propagation direction, while the HSFL is structure-independent and self-orients perpendicularly to the polarization direction of the incident pulses. The findings not only introduce an optical approach to prepare nano-textured carbon materials for future energy and regenerative-medicine applications but also reveal important insights into the underlying formation mechanisms of LIPSS on complex three-dimensional surfaces.
Design of hollow tapered PMMA polymeric microneedles for enhanced structural stability and drug delivery efficiency
Authors: Gera Aswani Kumar , Burra Rajesh Kumar
Published: January 2025

Microneedles have emerged as a promising alternative to conventional, or so-called hypodermic, needles for transdermal drug delivery. A meticulous design of microneedle geometry is crucial for balancing mechanical stability and fluid flow of drugs through these microneedles. This research paper analyzes the mechanical performance and fluid flow behavior of hollow cylindrical tapered shaped microneedles with polymethyl methacrylate, a biocompatible polymer, as material, considering its mechanical properties and also the material being widely used in biomedical applications. The finite element analysis tool is used to enhance the microneedle design by varying the outer base radius and tip radii to mitigate the von Mises stress that is exhibited during axial load and bending load conditions. In addition, microfluidic analysis is to assess the fluid flow behavior through the hollow microneedles, measuring the flow rates of fluids (water, glucose, and insulin).Simulated results reveal that an axial stress of 3.26 × 106 N/m2 and bending stress of 2.31 × 107 N/m2 were reported, which are below the yield strength of the material and satisfy the criteria for successful microneedle penetration. Flow rate analysis of water reports that 834.42 μl/min and 5396.94 μl/min and for glucose as 412 μl/min and 3648 μl/min, and that of insulin as 834 μl/min and 5244 μl/min for applied inlet pressure of 10 and 100 kPa, respectively. The flow rates reveal that water and insulin exhibit nearly identical flow rates, indicating that the proposed microneedles are capable of efficiently delivering viscous fluids.
Visible-spectrum (405–505 nm) low-temperature-deposited deuterated (D) SiNx-SiOy waveguides
Authors: Markham Keith , Rabbani Mohammad , Hsiao Fu-Chen , Wierer Jonathan , Kish Fred
Published: January 2025

Deuterated silicon nitride (SiNx:D)–silicon oxide (SiOy:D) waveguides grown by low-temperature (300 °C) plasma-enhanced chemical vapor deposition (PECVD) operating in the violet (405 nm) to cyan (505 nm) visible spectrum are demonstrated. The waveguides exhibit low insertion losses ranging from 3.2 dB/cm (405 nm) to 0.8 dB/cm (505 nm). The performance of these waveguides is competitive to conventional SiNx waveguides that require significantly higher processing temperatures (≥800 °C). The low-temperature deposition and low loss of these waveguides enable advanced heterogeneous integration schemes for visible-spectrum photonic integrated circuits.
Tailoring beam profile and OAM spectrum in domain-engineered nonlinear photonic crystals
Authors: Zhang Xinyu , Li Hangyu , Liu Shiqiang , Chen Yan , Zhu Zhihan , Liu Hui , Zhu Shining , Hu Xiaopeng
Published: January 2025

Nonlinear frequency conversion provides a powerful tool to generate and manipulate structured light at new wavelengths. In this work, to meet the demands of applications such as high-capacity optical communications and high-dimensional entanglement generation, we use ferroelectric domain engineering to generate frequency-doubled light beams carrying orbital angular momentum (OAM) superposition states and with adjustable radial intensity distribution. Angular and radial phase modulations were introduced into the modulation function of the second-order nonlinear coefficient distribution of lithium tantalate nonlinear photonic crystals, achieving simultaneous tailoring of the OAM spectrum and the radial intensity profile of the second harmonic (SH) waves. As a representative example, we demonstrate the generation of a SH wave that carries a comb-like OAM spectrum, with the radial intensity distribution concentrating on a ring with a specific radius. In addition, the nonlinear photonic devices developed in this work feature polarization insensitivity and broadband characteristics.
Investigation of the wavy leading edge suppressing suction surface separation in a single-stage axial flow compressor
Authors: Zhang Haoguang , Feng Yiming , Dong Jiezhong , Xiao Jinhang , Chu Wuli
Published: January 2025

In order to improve the compressor efficiency, a wavy leading edge design method is introduced. A single objective optimization method is adopted to find the optimal wavy leading edge design and the effect of the wavy leading edge on the suction surface separation of a subsonic compressor stator is investigated by means of numerical simulations and controlling the sinusoidal function. The optimization results indicate that the amplitude has a significant impact on the compressor efficiency. Three amplitude schemes were studied, and the results show that as the amplitude increases, the efficiency of the compressor first increases and then decreases. The optimal schemes can reduce flow loss by 21.8% and increase the peak efficiency of the compressor by 1.46%. The wavy leading edge blades could change the static pressure distribution and induce the formation of leading edge vortex pairs behind the valley to improve the ability of resisting the separation for the flow.
Analysis of intramolecular modes of liquid water in two-dimensional spectroscopy: A classical hierarchical equations of motion approach
Authors: Hoshino Ryotaro , Tanimura Yoshitaka
Published: January 2025

Two-dimensional (2D) vibrational spectroscopy is a powerful means of investigating the structure and dynamics of complex molecules in condensed phases. However, even in theory, analysis of 2D spectra resulting from complex inter- and intra-molecular motions using only molecular dynamics methods is not easy. This is because molecular motions comprise complex multiple modes and peaks broaden and overlap owing to various relaxation processes and inhomogeneous broadening. On the basis of an anharmonic multimode Brownian oscillator model with nonlinear system–bath coupling, we have developed an approach that simulates 2D spectra, taking into account arbitrary modes of intermolecular and intramolecular vibrations simultaneously. Although only two-mode quantum calculations are feasible with this model, owing to high computational costs, here we restrict ourselves to the classical case and perform three-mode calculations. We demonstrate the applicability of our method by calculating 2D correlation infrared spectra of water for symmetric stretching, antisymmetric stretching, and bending modes. The quantum effects of these results are deduced by comparing 2D quantum spectra previously obtained for two intramolecular modes with those obtained using our classical approach under the same physical conditions. The results show that the 2D spectra calculated by separating the stretching modes into symmetric and asymmetric modes provide better descriptions of peak profiles, such as the splitting of cross-peaks.
Measurements of in-plane thermophysical properties on nanoscale-thick films by lock-in thermography
Authors: Alasli Abdulkareem , Iguchi Ryo , Uchida Ken-ichi , Nagano Hosei
Published: January 2025

We demonstrate a versatile technique for measuring the in-plane thermal conductivity, in-plane thermal diffusivity, and volumetric heat capacity of nanoscale-thick films by means of lock-in thermography. The technique relies on the thermal analyses of imaged lock-in temperature distribution over the surface of films generated by an on-chip line heater. This enables simultaneous estimation of the properties for a free-standing membrane or multilayered thin films deposited on the membrane. We validate the usability of this technique by determining the thermophysical properties of Ni films with different nanoscale thicknesses. This technique also enables measurements under an external magnetic field, facilitating investigation of magneto-thermal transport properties. Thus, the proposed approach will be useful for exploring nanoscale thermal transport properties in thin films and thermal management systems.
Augmentation of predictive turbulence modeling applied to low pressure turbines using adaptive field inversion
Authors: Gou Lifeng , Ye Jian , Zou Zhengping
Published: January 2025

Based on the framework of field inversion and machine learning, an adaptive modification for Reynolds-Averaged Navier–Stokes-based turbulence models is proposed for the simulation of low-pressure turbine cascades involving flow separation. This method adjusts the results of turbulence by modifying the source terms correspondingly at different spatial locations. First, the specific regions for modification are obtained by Gaussian mixture models adaptively according to the baseline results and the spatial distribution of the correction term is inferred by an ensemble-based inversion method with effective utilization of high-fidelity data. Then a corrective model form of the flow quantities calculated with the baseline model is established by the Gradient Boosting Decision Tree model and used for the simulation of T106 cascade cases. The results demonstrate that with the adaptive modified turbulence model, reduced deficiency on predicting the load distribution can be obtained. The modified model can also predict a more accurate separation onset by damping eddy viscosity in separated region for case out of the training set. With correction added to the turbulence model solely in a specific region, the computational cost can be reduced compared with full-field inversion, and the method can be possibly applied in simulating the three-dimensional flow considering rotation effects.
Analysis of unstable flow characteristics in the blade region of Francis pump-turbine under non-design conditions
Authors: Zhou Jiayan , Zhang Yuquan , Zheng Yuan , Xu Lianchen , Li Chengyi , Zang Wei , Yan Xiaotong
Published: January 2025

Under non-design situations, the Francis pump-turbine, a frequently employed core energy conversion device in pumped storage power plants, plays a significant role in ensuring their stable operation. This article examines the unstable flow inside a Francis pump-turbine using energy gradient theory and numerical computations and model experiments. Research has indicated that forced impacts and flow separation between fluids and blades are significant causes of deteriorating mechanical energy gradients, whereas non-optimal angles between stay and guide vanes can readily cause flow separation. The strong helical flow at the blade inlet is the primary cause of the unstable flow, and the hub and blade outlet are the primary locations for the high shear force work area brought on by large-scale vortex structures, and the middle portion of the impeller blade is where the unstable flow field begins and needs more attention.
Influence of thermal effects on the dynamic behavior of blood droplets on a superhydrophobic surface
Authors: Lu Longsheng , Kou Jinwei , Tang Biao , Xie Yingxi , Gao Jiao , Wang Long , Li Kaikai
Published: January 2025

The high temperatures generated during the operation of high-frequency surgical electrodes can cause biological tissues (especially blood) to crust and adhere to the electrode surface, seriously affecting the quality and efficiency of the procedure. Currently, an effective anti-adhesion approach is to construct superhydrophobic microstructures on the electrode surface. However, the micro-mechanisms of antiadhesion under the influence of high temperatures are still incomplete. Herein, this study focuses on the dynamic growth and evolution of blood droplets on a superhydrophobic microstructured surface (SMS) under thermal effects above 100 °C. The research demonstrated that as the substrate temperature increases gradually, the internal fluid perturbation of the blood droplets intensifies, and the air layer trapped by the SMS is subjected to thermal expansion. Consequently, the SMS is unable to provide sufficient adhesion for the growth of the blood coagulum, leading to a significant decrease in the stability of its binding to the substrate and thus the formation of self-desorption. Particularly, it was discovered for the first time that the shell wall of the blood coagulum is layered, a phenomenon related to mass transfer in the Marangoni flow within the droplet under thermal effects. These detailed findings facilitate comprehension of the anti-adhesion mechanism of SMSs, thereby providing a theoretical foundation for the optimization of future surgical electrodes.
Impact of cylinder corner modification on fluid dynamics and heat transfer: Corner cut size and cut angle
Authors: Afzal Kamran , Younis M. Yamin , Chuddher Bilal Akbar , Ikram Faraz , Ijaz Asad , Alam Md. Mahbub
Published: January 2025

The impact of corner modifications on fluid dynamics and heat transfer characteristics of a square cylinder is numerically investigated at a Reynolds number Re = 150 (based on cylinder width W), with corner cut size C* (= C/W) = 0–0.5 and cut angle α  =  0°–45°, where C is the corner cut size. The corner cut modification gradually modifies the baseline square cylinder (C* = 0, α  =  0°) to a number of octagonal and hexagonal shapes and finally to a diamond cylinder (C* = 0.5, α  =  45°) through a total of 64 distinct shapes. The focus is given on the dependence on C* and α of time-averaged and fluctuating flow fields around the cylinders, Strouhal numbers, fluid forces, and time-mean Nusselt numbers. Results of fluid forces and Nusselt number are also compared to those of circular cylinders at the same Reynolds number. Time-average and fluctuating fluid forces are reduced for several modified shapes compared to the baseline case, with some modifications yielding forces even smaller than those observed for the circular cylinder. Heat transfer improves for all modified shapes relative to the baseline square cylinder yet remains lower than that of the circular cylinder. The time-averaged flow fields reveal three distinct wake patterns depending on C* and α. The study identifies several shapes with improved fluid dynamic characteristics that can be applied in mechanical, civil, and environmental engineering applications.
Erosion characteristics of pulsed waterjets issuing from a novel ultrasonic nozzle
Authors: Cai Jingrun , Xiong Jie , Wang Lei , Li Deng , Kang Yong , Ma Yanzhao , Chen Yulong
Published: January 2025

By taking advantage of the stress wave effect, pulsed waterjet has higher working efficiency when used in mining, cleaning, and surface treatment. To clarify the erosion performance of our newly designed ultrasonic pulsed waterjet (UPWJ), effects of the ultrasonic power and erosion time were experimentally studied and compared with a continuous waterjet (CWJ). Homogeneous material 6061 aluminum alloy suitable for evaluating the erosion performance of waterjet was used as specimen. The erosion morphology, surface parameters, and material removal rate were used to evaluate the performance. Results show that ultrasonic power and erosion time have a positive effect on the erosion capacity of UPWJ, and the erosion edge was more rounded, with the center showing an erosive layer owing to the water hammer effect. Compared with CWJ, the erosion depth of UPWJ was significantly increased by 34% at 450 W and 3 min, while the erosion area is hardly enlarged, meaning that UPWJ has a higher energy density. Moreover, the roughness of erosion pit of UPWJ is generally larger, and the uniformity of the erosion surface is better. The material removal rate of UPWJ is pronouncedly larger than that of CWJ, with a maximum enhancement of 76% at 450 W and 2 min. Besides, the specific energy consumption of UPWJ is up to 20% lower, showing that UPWJ has a higher energy efficiency.
Damage and recovery of flagella in soil bacteria exposed to shear within long microchannels
Authors: Carrillo-Mora Juan Pablo , Monteiro Moniellen Pires , Lodeiro Aníbal R. , Marconi V. I. , Cordero María Luisa
Published: January 2025

The swimming motility of bacteria is driven by the action of bacterial flagellar motors, whose outermost structure is a long and thin helicoidal filament. When rotated, the fluid medium exerts an anisotropic viscous drag on the flagellar filaments, ultimately leading to bacterial propulsion. The flagellar filaments are protein-based flexible structures that can break due to interactions with fluid flows. Here, we study the evolution of flagellar filaments in the soil bacterium Bradyrhizobium diazoefficiens after being exposed to shear flows created in long microchannels, for shear rates between 1 and 105  s−1, and for durations between tens of milliseconds and minutes. We demonstrate that the average swimming speed and fraction of swimming cells decrease after exposition to shear, but both parameters can recover, at least partially, with time. These observations support the hypothesis that shear flows cut flagellar filaments but that reversibly damaged bacterial flagellar motors can be restored, thanks to filament regeneration. By fitting our observations with phenomenological expressions, we obtain the individual growth rates of the two different flagellar filaments that B. diazoefficiens possesses, showing that the lateral filaments have a recovery time of about 40 min while the subpolar one requires more than 4.5 h to regrow. Our work demonstrates that simple monitoring of bacterial motility after exposition to shear can be used to characterize the process of flagellar filament breakup and growth, a phenomenon widely present in bacteria swimming in porous soil and exposed to shear flows due to rainfall and watering systems.
Metasurface-based single-pixel recognition through scattering media
Authors: Zhang Xuan , Xiong Jiahao , Fu Ai , Zheng Guoxing , Li Zile , Liu Hong-Chao
Published: January 2025

Taking advantage of optoelectronic hybrid neural networks, we propose a metasurface-single-pixel hybrid neural network for object recognition. It employs only eight illumination patterns trained by the digital neural network to convolve the object from two-dimensional images into only eight intensity values measured by a single-pixel detector, achieving a 93.8% accuracy rate in handwritten digit recognition. Our work therefore paves an image-free way for metasurface-based object recognition using only a single-pixel detector, which exhibits its powerful information compression and accurate extraction capabilities coupled with a compact structural design.
Unsteady characteristic in integrated flameholder combustion flow field
Authors: Zhou Jiawei , Jin Jie , Zhang Minqi , Wang Fang , Xu Xingping , Zhou Chunyang
Published: January 2025

Integrated flameholder is widely used in advanced combustors. The unsteady characteristic of integrated flameholder combustion flow fields is critical. In this study, experiments and numerical simulation were carried out for the inspection of methods and analysis of their unsteady characteristic. By comparison of experimental and numerical results in two cases, the relative error is found to be about 10%.The comparative results denote that the large eddy simulation-transported probability density function method has positive performance in the calculation of pressure fluctuation in integrated flameholder combustion fields. After evaluating the numerical methods, the velocity and temperature field were analyzed as the basis of further unsteady analysis. Then, the fast Fourier transform (FFT) and empirical mode decomposition (EMD) were applied to analyze the velocity fluctuation and pressure fluctuation in the combustion flow field. The distribution and tendency of fluctuation frequency and amplitude are related to various factors. The velocity fluctuation frequency is low near the central axis, and the velocity fluctuation amplitude is high on both sides of the central axis; the pressure fluctuation frequency is low on either side of the recirculation zone, and the pressure fluctuation amplitude gradually increases downstream as the flame develops. Besides, the result of unsteady analysis demonstrates that FFT is suitable for the analysis of fluctuation amplitude, and the combination of EMD and FFT can give more information on the fluctuation frequency from complex nonlinear data.
Microbial in-situ foam generation for enhanced oil recovery
Authors: Fu Jian , Liu Yulong , Zhang Cenqian , Wang Chenyue , Sun Shanshan , Dong Hao , She Yuehui , Zhang Fan
Published: January 2025

In-situ foam generation can effectively improve reservoir heterogeneity and enhance oil recovery. In order to solve the problems of environmental pollution and difficult demulsification of emulsion caused by chemical methods, this study selected green and foaming Pseudomonas aeruginosa (PA) to carry out foam stability test, crude oil emulsification demulsification experiment, sand-filled pipe experiment, and micromodel displacement experiment. PA bacteria can produce foam at 25–45 °C, high salinity 5%, and weak acid and weak alkali environment. The foam size is 20–100 μm, and the foam half-life is 109 min. After adding a certain amount of polymer and nanoparticles, the half-life can be increased by 14.3% –35.3%. The foam culture solution has good viscosity reduction effect and emulsification performance. After treatment, the viscosity of crude oil decreased by 96.26%, the gum content decreased by 9.474%, and the saturated hydrocarbon content increased by 11.136%. Among them, the emulsion can be well demulsified by organic acids, and the crude oil recovery rate is as high as 91.47%. The culture medium has good oil washing ability, which can improve the recovery rate of crude oil and increase the recovery rate of low permeability tube with permeability range of 8.2% × 30.8%. At the same time, the foam has good stability, deformation, and plugging ability, which can effectively improve the heterogeneity of the reservoir. The foam generated in situ by microorganisms enhances oil recovery by profile control and oil washing.
Hydraulic oscillations and stability testing of a novel shaft coaxial surge chamber with small load disturbances in pumped storage power stations
Authors: Zhao Wen-long , Zhang Jian , Chen Sheng , Yang Xiao-li , Yu Xiao-dong , He Wei , Liu Yi
Published: January 2025

Surge chambers play a critical role in moderating oscillations in pumped storage power stations after load disturbances. Owing to the high costs, increased risks, and extended construction times associated with conventional surge chambers (CSCs), we proposed a shaft coaxial surge chamber (SCSC) as an alternative, which was otherwise a compact, economical, and construction-friendly structural configuration. The present study aimed to investigate the hydraulic oscillations, stability, and flow characteristics of an SCSC compared to a CSC under disturbance conditions. Physical models of both types of surge chambers were developed and validated. The results indicated that the novel SCSC system could maintain stability before and after disturbances; its hydraulic fluctuations were slightly higher than those of the CSC, particularly under pumping conditions. During the disturbance, the water level fluctuation amplitudes in the SCSC were at least 1.43 and 2.24 times those of the CSC under different working conditions with 10% flow disturbance. As the disturbance frequency increased, the stability of the SCSC approached that of the CSC. Moreover, a new discharge coefficient range of 0.9–1.2 for the SCSC was proposed, increasing the conventional standard values by 1.5 times. In conclusion, the higher discharge coefficient and unstable flow patterns in the connecting pipe are critical mechanisms that influence the hydraulic oscillations of the SCSC. These findings provide valuable theoretical guidance for practical applications.
Type-I and type-II interfaces in a MoSe2/WS2 van der Waals heterostructure
Authors: Rafizadeh Neema , Agunbiade Gbenga , Scott Ryan J. , Vieux Monique , Zhao Hui
Published: January 2025

We report experimental evidence that MoSe2 and WS2 allow the formation of type-I and type-II interfaces, according to the thickness of the former. Heterostructure samples are obtained by stacking a monolayer WS2 flake on top of a MoSe2 flake that contains regions of thickness from one to four layers. Photoluminescence spectroscopy and transient absorption measurements reveal a type-II interface in the regions of monolayer MoSe2 in contact with monolayer WS2. In other regions of the heterostructure formed by multilayer MoSe2 and monolayer WS2, features of type-I interface are observed, including the absence of charge transfer and dominance of intralayer excitons in MoSe2. The coexistence of type-I and type-II interfaces in a single heterostructure offers opportunities to design sophisticated two-dimensional materials with finely controlled photocarrier behaviors.
An analytical model of label-free nanoscale chemical imaging reveals avenues toward improved spatial resolution and sensitivity
Authors: Zhang Yide , Yilmaz Ufuk , Lukasievicz Gustavo Vinicius Bassi , O’Faolain Liam , Lendl Bernhard , Ramer Georg
Published: January 2025

Atomic force microscopy–infrared spectroscopy (AFM-IR) is a photothermal scanning probe technique that combines nanoscale spatial resolution with the chemical analysis capability of mid-infrared spectroscopy. Using this hybrid technique, chemical identification down to the single molecule level has been demonstrated. However, the mechanism at the heart of AFM-IR, the transduction of local photothermal heating to cantilever deflection, is still not fully understood. Existing physical models only describe this process in few special cases but not in many of the types of sample geometries encountered in the practical use of AFM-IR. In this work, an analytical expression for modeling the temperature and photothermal expansion process is introduced, verified with finite element simulations, and validated with AFM-IR experiments. This method describes AFM-IR signal amplitudes in vertically and laterally heterogeneous samples and allows studying the effect of position and size of an absorber, pump laser repetition rate and pulse width on AFM-IR signal amplitudes and spatial resolution. The analytical model can be used to identify optimal AFM-IR experimental settings in conventional and advanced AFM-IR modes (e.g., tapping mode, surface-sensitive mode). The model also paves the way for signal inversion based superresolution AFM-IR.
Life history is a key driver of temporal fluctuations in tropical tree abundances
Authors: Jops Kenneth , Dalling James W. , O’Dwyer James P.
Published: January 2025

The question of what mechanisms maintain tropical biodiversity is a critical frontier in ecology, intensified by the heightened risk of biodiversity loss faced in tropical regions. Ecological theory has shed light on multiple mechanisms that could lead to the high levels of biodiversity in tropical forests. But variation in species abundances over time may be just as important as overall biodiversity, with a more immediate connection to the risk of extirpation and biodiversity loss. Despite the urgency, our understanding of the primary mechanisms driving fluctuations in species abundances has not been clearly established. Here, we introduce a theoretical framework based around life history; the schedule of birth, growth, and mortality over a lifespan, and its systematic variation across species. We develop a mean field model to predict expected fluctuations in abundance for a focal species in a larger community, and we quantify empirical life history variation among 90 tropical forest species in a 50 ha plot in Panama. Putting theory and data together, we show that life history provides a critical piece of this puzzle, allowing us to explain patterns of abundance fluctuations more accurately than previous models incorporating demographic stochasticity without life history variation, and without introducing unobserved couplings between species and their environment. This framework provides a starting point for more general models that incorporate multiple factors in addition to life history variation, and suggests the potential for a fine-grained assessment of extirpation risk based on the impacts of anthropogenic change on demographic rates across life stages.
Dry matter and fiber yields, and the fiber characteristics of five nettle clones (Urtica dioica L.) organically grown in Austria for potential textile use
Authors: Hartl Anna , Vogl Christian R.
Published: January 2025

Fiber nettle (Urtica dioica L.) has potential as a fiber crop in the natural textiles industry, an industry requiring production by organic methods. No recent data on yield potentials and quality of this crop using these methods are available to farmers. Five fiber nettle clones were cultivated between 1997 and 1999 in a randomized block design with four replications per clone on an organic farm in Lower Austria. The harvests from the second and third cultivation year were used for further analysis. The dry matter yield (stalks) of the five nettle clones in the second cultivation year (1998) ranged from 2.3 to 4.7 Mg ha−1. The dry matter yield of the third cultivation year (5.6 to 9.7 Mg ha−1) was more than double that of the second year. The large increase in the yield of the third year was a result of an increase in the height (20 to 40 cm higher) and a doubling of the number of stalks per plot compared with those from the second cultivation year. Undersowing with clover had a positive effect on fiber nettle growth. The fiber content after chemical processing ranged between 8 and 16% of the dry matter in both the second and third cultivation years. The fiber yields ranged from 335 to 411 kg ha−1 in the second year and from 743 to 1016 kg ha−1 in the third year. Clones with a high dry matter yield had a low fiber content and vice versa. There was no significant difference in the fiber quality (fiber strength, elongation, fiber fineness, length of fiber) of the five nettle clones. Due to the different consistency in the upper and lower part of the stalk and to fiber processing methods, the fiber material is generally very heterogeneous. This work shows that the cultivation of fiber nettle by organic methods in Austria is possible and that it produced well in the third year. Organically grown fibers of nettle are suitable for textile use; however, further development of an economic and functional high-yielding method for fiber processing, and efficient marketing are essential for the success of nettle fiber in the textile market.
How do farmers who adopt multiple conservation practices differ from their neighbors?
Authors: Upadhyay Bharat M. , Young Douglas L. , Wang Holly H. , Wandschneider Philip
Published: January 2025

Wind erosion is a serious environmental problem in the inland Pacific Northwest, US. In addition to onfarm damage to soil and crop quality, it causes off-farm damage, including human respiratory illness, traffic accidents and diminished recreational values. Three key practices for effectively controlling wind erosion in eastern Washington are reduced tillage, continuous spring cropping and vegetative wind strips. Although these are effective in controlling wind erosion, their adoption by farmers in the region has been slow. Technology adoption theory has been classified into three paradigms: income, utility and innovation-adoption. This study on adoption of wind erosion control practices draws from all three paradigms. However, unlike most past research, this study distinguishes between single-practice adopters and multiple-practice adopters, and compares single-practice adopters with zero-practice adopters. Data were obtained from a random sample survey of 266 farmers in six semi-arid counties in a region of east-central Washington State prone to wind erosion. Statistical results revealed: (1) that adopters of multiple conservation practices contrast more sharply with non-adopters than do adopters of a single conservation practice; and (2) adopters of a single practice differ more from zero-practice adopters than they do from all other farmers (including adopters of other practices). More specifically, this study recognizes heterogeneity among ‘adopters’ in erosion control, and suggests that there may be some hierarchy among adopters in strength of innovation. It also supports earlier findings-by sociologists that early adopters have more financial resources or larger farms and that education may aid adoption. Adopters were more aware of an erosion control educational program. Multiple-practice adopters are a distinct identifiable group, who may play a key role as innovators who can influence neighbors to adopt effective conservation practices. These individuals also possess unique information on the comparative cost, yields and technical challenges of alternative conservation practices that could be used on farms with similar soil and climatic conditions. Knowledge of the attributes associated with innovative multiple-practice adopters may permit soil conservation policymakers and field staff to target educational programs more accurately during the early stages of technology dissemination. Conservation-practice dissemination strategies may benefit by including innovative farmers in leadership roles in the initial stage of conservation education programs.
Arginylation of ⍺-tubulin at E77 regulates microtubule dynamics via MAP1S
Authors: MacTaggart Brittany , Wang Junling , Tang Hsin-Yao , Kashina Anna
Published: January 2025

Arginylation is the posttranslational addition of arginine to a protein by arginyltransferase-1 (ATE1). Previous studies have found that ATE1 targets multiple cytoskeletal proteins, and Ate1 deletion causes cytoskeletal defects, including reduced cell motility and adhesion. Some of these defects have been linked to actin arginylation, but the role of other arginylated cytoskeletal proteins has not been studied. Here, we characterize tubulin arginylation and its role in the microtubule cytoskeleton. We identify ATE1-dependent arginylation of ⍺-tubulin at E77. Ate1−/− cells and cells overexpressing non-arginylatable ⍺-tubulinE77A both show a reduced microtubule growth rate and increased microtubule stability. Additionally, they show an increase in the fraction of the stabilizing protein MAP1S associated with microtubules, suggesting that E77 arginylation directly regulates MAP1S binding. Knockdown of Map1s is sufficient to rescue microtubule growth rate and stability to wild-type levels. Together, these results demonstrate a new type of tubulin regulation by posttranslational arginylation, which modulates microtubule growth rate and stability through the microtubule-associated protein, MAP1S.
Suppression of the coffee ring effect with undetectable disturbance of the deposit
Authors: Sheng Shiqi , Fang Zhening , Gao Shiyu , Chen Ruoyang , Wang Ying , Yang Haijun , Fang Haiping
Published: January 2025

Suppressing the coffee ring effect (CRE) of an aqueous suspension through manipulation without affecting the remaining deposit is highly desired for practical applications; clearly such efforts are extremely challenging. Here, we show the CRE suppression with undetectable disturbance of the deposit on carbon-based surfaces. This is achieved by adding ammonium bicarbonate (NH4HCO3), benefited from the dissociation of NH4HCO3 to produce NH4
+, together with its decomposition into NH3 and CO2 molecules. Surprisingly, NH4
+ can also function as Na+/K+ to suppress CRE through the cation- interactions although its hydrate state is only partially positively charged. We further successfully apply this approach to enhance the morphology, resistance, and color uniformity for the deposits of graphene oxide quantum dots, conductive inks, and organic dyes, respectively. Our work provides a practical strategy to improve the performance of the fabricated devices, paving the way for the development of high-accuracy manufacturing techniques in diverse industries.
MAFF-Net: PCB defect detection via feature-enhancement fusion
Authors: Chen Jian , Wang Shouyin , Chen Ziyuan , Huang Wenzhong , Lin Li , Hong Huiqun , Chen Geng , Jiang Zhuwu
Published: January 2025

Defect detection of printed circuit board (PCB) is of significant practical importance to ensure quality control in the production process. However, traditional defect detection methods suffer from limitations such as low detection accuracy and poor generalization ability. To tackle these issues, we propose a novel deep learning-based defect detection method for bare PCBs through multi-attention adaptive feature-enhancement fusion (AFF). First, we utilize ResNext101 as the backbone for feature extractor and embed a normalization-based attention mechanism in a residual structure, aiming at improving the feature extraction capability of the network. Second, we introduce an AFF module, which leverages multi-scale feature extraction and feature fusion to facilitate information interaction and enhance the correlation of feature information between channels. Finally, we incorporate the coordinate attention mechanism into AFF to highlight the target area for boosting detection accuracy. The experimental results demonstrate the effectiveness of the proposed method, which achieves a mean accuracy precision (mAP) of 99.01

%

on a publicly available PCB defect dataset.
Analytic weak-stable manifolds in unfoldings of saddle-nodes*
Authors: Kristiansen Kristian Uldall , Szmolyan Peter
Published: January 2025

Any attracting, hyperbolic and proper node of a two-dimensional analytic vector-field has a unique strong-stable manifold. This manifold is analytic. The corresponding weak-stable manifolds are, on the other hand, not unique, but in the nonresonant case there is a unique weak-stable manifold that is analytic. As the system approaches a saddle-node (under parameter variation), a sequence of resonances (of increasing order) occur. In this paper, we give a detailed description of the analytic weak-stable manifolds during this process. In particular, we relate a ‘flapping-mechanism’, corresponding to a dramatic change of the position of the analytic weak-stable manifold as the parameter passes through the infinitely many resonances, to the lack of analyticity of the centre manifold at the saddle-node. Our work is motivated and inspired by the work of Merle, Raphaël, Rodnianski, and Szeftel, where this flapping mechanism is the crucial ingredient in the construction of

C
∞

-smooth self-similar solutions of the compressible Euler equations.
One-week test–retest stability of heart rate variability during rest and deep breathing
Authors: Schumann Andy , Lukas Franziska , Rieger Katrin , Gupta Yubraj , Bär Karl-Jürgen
Published: January 2025

Objective. Heart rate variability (HRV) is an important indicator of cardiac autonomic function. Given its clinical significance, reliable HRV assessment is crucial. Here, we assessed test–retest stability, as a key aspect of reliability, quantifying the consistency of a measure when repeated under the same conditions. Approach. This observational study includes healthy individuals. A 20 min electrocardiogram was recorded at rest in a supine position and during deep breathing in two lab sessions within one week, at the same time of day. HRV indices from time domain, frequency domain, nonlinear dynamics, and information-theoretic complexity were assessed using a validated toolbox. Additionally, heart rate variations per respiratory cycle were evaluated during deep breathing. Lifestyle factors such as perceived stress, mood, physical activity, sleep quality were assessed prior to both sessions. Intra-class correlation (ICC) and coefficients of variation (CVs) were used to assess the concordance between the two measurements and the relative deviation, respectively. Main results. From 62 screened individuals, 51 participants were recruited from the local community. One participant opted out for personal reasons, and another with frequent premature beats was excluded, leaving a final sample of 49 individuals. Most self-rated psychological and lifestyle indicators showed substantial agreement, though participants reported less stress and better mood in the second session. At rest, ICC of HRV ranged from 0.50 to 0.83, with CV from 5% to 41%. Spectral HRV measures were less reliable than time domain parameters. Nonlinear and time domain features had substantial to nearly perfect agreement. Complexity measures had low CVs but limited test–retest correlation. The stability indices of HRV during deep breathing were not significantly different from those during rest. Test–retest differences in root mean square of the successive beat-to-beat interval difference were not sufficiently explained by lifestyle factors. Significance. Test–retest stability of HRV depends considerably on chosen measures. Our data suggest that HRV can be assessed reliably using time-domain indices at rest.
Destabilizing effects of nonthermal nonextensive particles on electromagnetic Alfvén-cyclotron modes in anisotropic non-equilibrium collision-free plasmas
Authors: Bilal Muhammad , Rehman Aman-ur , Ahmad Mushtaq , Shahzad Muhammad Ahsan , Sarfraz Muhammad
Published: January 2025

This study explores the effects of nonthermal nonextensive particles on the destabilization of Alfvén-cyclotron (AC) modes in collisionless anisotropic non-equilibrium magnetized plasmas. We employ the superextensive and subextensive anisotropic Cairns-Tsallis distribution functions (CTDF) through two distinct theoretical frameworks: model-I (M-I) and model-II (M-II). M-I delineates a temperature model that is invariant with respect to nonthermality and nonextensivity, whereas M-II incorporates a temperature that intrinsically depends on these parameters. Utilizing the linear plasma kinetic theory, we derive the dielectric response function and solve it numerically for AC modes in superextensive and subextensive Cairns-Tsallis distributed plasmas (CTDPs) for both models. Intriguingly, we observe a marked difference in the behavior of AC instability for the two models; M-II significantly augments instability growth in superextensive CTDP compared to M-I, while an opposite trend is manifested in the case of subextensive CTDP. Our investigation further elucidates the impact of pivotal parameters such as plasma beta (β
∥) and ion temperature anisotropy (η

i
) on real and imaginary frequencies of AC modes. This study also offers an in-depth comparative analysis of AC instability in anisotropic CTDP (encompassing both subextensive and superextensive cases), as well as in anisotropic Cairns, and bi-Maxwellian plasmas.