bluuebunny/crossref_metadata_2025 huggingface dataset:
Asteroid material classification based on multi-parameter constraints using artificial intelligence
Authors: Ge Jiayi , Zhang Xiaoming , Li Juan , Li Mingtao , Tang Yijun , Jiang Yunxiao , Liu Chengzhi , Kang Zhe , Zeng Xianqun , Jiang Xiaojun
Published: November 2024

Context. Material types of asteroids provide key clues to their evolutionary history and contained resources. The Gaia mission has released extensive low-resolution spectral observation data of small Solar System bodies. However, methods for classifying asteroids based on low-resolution space-based spectra are still inadequate, and do not fully leverage the complementary features of spectra and multiple intrinsic attributes of asteroids to achieve precise material classification.

Aims. Our goal is to propose a method with a higher generalization accuracy for asteroid material classification by integrating multi-source information, identifying optimal feature combinations for model inputs, and deepening the understanding of relationships among asteroid parameters.

Methods. The effective asteroid photometric, physical, and orbital parameters were screened using the information gain ratio and Spearman’s rank correlation coefficient. Then, artificial intelligence techniques were employed to combine asteroid spectra with the selected various parameters for six-class material classification. By comparing five machine learning models, we identified network structures with higher validation accuracy and stable generalization performance. Meanwhile, feature ablation experiments were conducted to determine the input parameter combinations suitable for different scenarios. Finally, based on the statistical results and model outputs, the constraint relationships among asteroid parameters were visualized and analyzed.

Results. The proposed AsterRF model achieved a validation accuracy of 92.2%, an improvement of approximately 7.8 percentage points compared to existing methods that use only spectra. V-type asteroids exhibited the highest classification accuracy, followed by A-type and D-type. X-type asteroids had the lowest precision and recall, and were easily confused with C-type. The model generally showed higher classification confidence for S-type asteroids. The top five attributes that the model focused on are the phase slope parameter (G), orbital type, albedo, H magnitude, and effective diameter. Additionally, the correlations between asteroid materials and other parameters were generally below 0.4.

Conclusions. Incorporating optimal asteroid parameter combinations can significantly enhance classification accuracy based on spectra. A dual-channel network that processes spectra and parameter inputs separately, and employs a self-attention mechanism for feature fusion is effective in combining multi-source asteroid information. Both the statistical correlations and model performance-based importance rankings of parameters contribute to understanding the constraint relationships among asteroid attributes.
Design of polarization-independent multilayer dielectric gratings: a reflection-phase threaded approach
Authors: Shen Sitong , Li Lifeng , Zeng Lijiang
Published: November 2024

We present a method to design polarization-independent multilayer dielectric gratings. In this method the reflection phases in transverse electric (TE) and transverse magnetic (TM) polarizations of the multilayer stack thread surface-relief grating at the top and the multilayer stack at the bottom together, allowing the two parts first to be designed separately and efficiently, and then to be combined to achieve simultaneously high diffraction efficiency and large fabrication tolerance. We find numerically that in general a periodic stack is unable to provide the top-grating-demanded phase difference between TM and TE polarizations; adequate aperiodic layers atop of a periodic stack are needed. The analytic diffraction efficiency formula of a recent work [J. Opt. Soc. Am. A 41, 252 (2024). https://doi.org/10.1364/JOSAA.511422] is used at various places of the presented optimization algorithm to save computation time. An example grating with rectangular surface-relief profile and another with trapezoidal profile were successfully designed, validating the effectiveness of this design method.
Evaluation of Clinical and Laboratory Findings of Sinusitis Complications in Children
Authors: Bulut Karakuş Arife Melike , Alkan Gülsüm , Emiroglu Melike , Tüter Öz Şadiye Kübra , Öztürk Mehmet , Gökmen Muhammet Fatih , Sahinoglu Mert , Kıymaz Meltem , Özyalvaç Büşra
Published: November 2024

Objective This retrospective study evaluates the demographic characteristics, clinical symptoms, laboratory results, treatment approaches, and outcomes of children with complications arising from bacterial sinusitis.

Methods Fifty-four pediatric inpatients with sinusitis complications admitted between September 2013 and October 2022 were included in the study. These patients were categorized into two groups: those with preseptal cellulitis (group 1) and those with orbital–intracranial complications (group 2).

Results The median age of the patients was 10.8 years, and 61.1% were males. Maxillary sinusitis (n = 40.74%) was the most common type of sinus involvement. Half of the patients exhibited preseptal cellulitis. The median age of our patients with intracranial complications was 13.7 years, while the median age of patients with orbital complications was 8 years. The predominant orbital–intracranial complication was meningitis, which accounted for 41% of the cases. All patients with a subdural abscess (n = 6) presented with frontal sinusitis, while all cases of cavernous sinus thrombosis (n = 3) involved the sphenoidal sinus. Surgical intervention was undertaken in 37% of cases. Streptococcus pneumoniae was the most frequently isolated microorganism. The median duration of hospital stay was 14 days, with a total median treatment duration of 21 days. There were no fatalities, although neurological sequelae were observed in 7.4% of patients (n = 4).

Conclusion Preseptal cellulitis and meningitis remain the most common complications of sinusitis in children. Adolescents with sinusitis should be monitored closely for intracranial complications. The prevalence of S. pneumoniae as the most frequently detected pathogen underscores the importance of vaccination.
Saturated absorption spectroscopy of methane around 1667 nm
Authors: Ding Yuan , Cao Fanghui , Li Jinke , Wang Jin , Liu Anwen , Tan Yan , Hu Shuiming
Published: November 2024

Methane is the second most important greenhouse gas after carbon dioxide, and the reduction of methane emissions is a key focus in IPCC reports. At present, atmospheric methane is monitored through ground-based observations and satellite remote sensing that depend on spectral characteristics. However, the positions of the methane lines provided by the widely utilized HITRAN database lack the precision required for accurate retrievals. In this work, we used cavity-enhanced absorption spectroscopy to record the absorption spectrum near the atmospheric detection window of methane at 1.66 µm. From the saturated absorption peaks (“Lamb dips”) observed on top of Doppler-broadened methane absorption lines, we determined the line positions with an absolute frequency accuracy of better than 2 MHz. The results also indicate the incompetence of the HITRAN database and theoretical models based on αb initio calculations of methane lines in this region.
Exploration of vibrationally resolved threshold photoelectron spectrum of difluoromethane within photon energy range of 12.45–14.10 eV
Authors: Cui Xueqi , Yang Xinlang , Yu Tongpo , Zhou Xiaoguo , Liu Shilin
Published: November 2024

Threshold photoelectron spectrum of CH2F2 in the photon energy range of 12.45–14.10 eV was re-investigated by means of a combination of photo-electron-photoion coincidence experiments and density functional theory calculations. A series of vibrational peaks were distinctly observed in this range. Using optimized geometries and vibrational frequencies of the CH2F2 neutral and its cation in ground state at the M06-2X/cc-pVTZ level of theory, Franck-Condon factor simulations were conducted. Taking into account anharmonicity influences, a perfect agreement between the simulated and experimental spectra has been achieved. From the reliable vibrational assignments, adiabatic and vertical ionization energies of CH2F2 are derived as 12.371 ± 0.010 eV and 13.281 ± 0.010 eV, respectively. In addition, the experimental frequencies of four vibrational modes with ai symmetry for CH2F2+(X2B1) ions are determined.
Effects of rotational excitation on vibrationally excited reaction of F+H2 (v=1, j=1)→HF+H at collision energy of 0.62 kcal/mol
Authors: Wang Wei , Xie Yurun , Huang Long , Yang Tiangang , Liu Shu , Xiao Chunlei , Zhang Donghui , Yang Xueming
Published: November 2024

The F+H2 reaction has long been a benchmark system in reaction dynamics. We report here a combined experimental and theoretical study on the F+H2(v=1, j=1) reaction at a collision energy of 0.62 kcal/mol. The rotational state-resolved differential cross sections (DCSs) as well as the integral cross sections (ICSs) were obtained by the crossed beam experiment and the quantum dynamical calculation. It is found that the rotationally excited state F+H2(v=1, j=1) reaction produces rotationally hotter but vibrationally colder products, compared with the rotational ground state reaction at the same total energy. The stereodynamics of the F+H2(v=1, j=1) reaction is also analyzed theoretically, showing that minor differences exist for the reactants initially prepared in different spatial alignments.
Multiple shock and acceleration processes of high-velocity flyers driven by the HEAVEN-I laser facility
Authors: Tian Baoxian , Sun Wei , Gao Zhixing , Hu Fengming , Wang Yuanhang , Wang Zhao
Published: November 2024

The experiments of high-velocity flyer acceleration were performed on the HEAVEN-I KrF laser facility with a long-pulse duration (∼ 28 ns). Double-layered flyers consisting of polystyrene and aluminum films can be accelerated to more than 10 km/s measured by VISAR. The polystyrene layer is used as the ablative material, insulation layer, and shock wave regulator. Multiple shock and acceleration processes were observed by adjusting the thickness of the polystyrene layer. We simulated and analyzed the multiple shock processes driven by the long laser pulses and square pressure pulses. The results indicate that the reverberation processes can be induced by the alternating shock and rarefaction waves due to the wave–interface interactions. The reverberations in the Al layer can modulate the pressure evolution and the fine structure of flyer acceleration history. Similar processes in the polystyrene layer can lead to a secondary or multiple shock loading process when the driving pulse duration is several times longer than the shock round trip time in the double-layered flyer. Multiple accelerations can effectively enhance the final velocities in the experimental and simulation results. However, multiple accelerations involve more complex shock loading and unloading processes, and flyers are more prone to breakup compared with single acceleration.
Efficient high-power diffraction-limited fiber laser with a record low quantum defect of 1.7%
Authors: Kalichevsky-Dong Monica T. , Bingham Samuel P. , Hawkins Thomas W. , Meeham Bailey , Dragic Peter , Ballato John , Dong Liang
Published: November 2024

In this work, we demonstrate an approach to potentially lower the quantum defect to ∼1% without significant compromise of efficiency. In a first demonstration, a diffraction-limited ∼154 W laser emitting at ∼993 nm with negligible amplified spontaneous emission, pumped at ∼976 nm, was achieved with a slope efficiency of ∼75% vs the launched pump power. The laser quantum defect is a record low of 1.7% for high-power (>100 W) solid-state lasers to the best of our knowledge. The output is only limited by the available pump power.
Mimicking somatic behavior of neurons using the integrate and fire model of 2D SnS memristive switching characteristics
Authors: Saha Soumi , Adepu Vivek , Sahatiya Parikshit , Dan Surya Shankar
Published: November 2024

This Letter presents the fabrication and characterization of a 2D SnS memristor, proposing its integrate and fire (I&F) model as a potential hardware implementation of neuronal somatic behavior. The memristor comprises a thin layer of tin (II) sulfide (SnS) sandwiched between copper (Cu) electrodes on a silicon (Si) substrate. This structure exhibits an impressive Roff:Ron ratio of 103 at a read voltage Vrd of 0.25 V with exceptionally low switching Vsw and set Vset voltages of 0.3 and 0.35 V, respectively, with ∼3 order variation between the maximum Rmax and Rmin resistances offered during single voltage sweep cycle. We have explained the memristive behavior using the dual ionic conduction mechanism in the SnS active layer. We extracted the real-time band diagram of SnS using ultraviolet photoelectron spectroscopy, explaining the low Vsw observed. We propose that the emulation of the I&F artificial neuron model exhibited by the fabricated device could serve as a promising application in the field of artificial neuron spiking.
Continuous broadband Rydberg receiver using AC Stark shifts and Floquet states
Authors: Song Danni , Jiao Yuechun , Hu Jinlian , Yin Yuwen , Li Zhenhua , He Yunhui , Bai Jingxu , Zhao Jianming , Jia Suotang
Published: November 2024

We demonstrate the continuous broadband microwave receivers based on AC Stark shifts and Floquet states of Rydberg levels in a cesium atomic vapor cell. The resonant transition frequency of two adjacent Rydberg states 78 S1/2 and 78 P1/2 is tuned based on AC Stark effect of 70 MHz radio frequency (RF) field that is applied outside the vapor cell. The use of the j=1/2 Rydberg states ensures that only a single mj sublevel is involved. The generated Rydberg Floquet states act to enhance the sensitivity of the AC-Stark-tuned states when the frequency is matched and further extend the bandwidths. We achieve microwave field measurements with over 1.172 GHz continuous frequency tuning and a sensitivity ranging from 280.2 nVcm−1Hz−1/2 to 14.6 μ Vcm−1Hz−1/2. The achieving of continuous frequency and high sensitivity microwave detection will promote the application of Rydberg receivers in the radar technique and wireless communication.
DDDNet: A lightweight and robust deep learning model for accurate segmentation and analysis of TEM images
Authors: Wang Chanjuan , Luo Huilan , Wang Jiyuan , Groom Daniel
Published: November 2024

The primary aim of this study was to develop an optimal, lightweight model for the segmentation of transmission electron microscopy (TEM) images. Our model is designed with a minimal parameter count, superior performance metrics, and robust adaptability to variations in substrates, nanoparticle sizes, and nanomaterial diversity within TEM images. In achieving this, we benchmarked our model against four deep learning models using subsets from the Bright-Field TEM(BF-TEM) and Au-TEM datasets. Our model demonstrated exceptional segmentation performance, requiring only 0.34 M parameters and 39.33 G floating-point operations. It also provided the most accurate estimates of average nanoparticle sizes, closely matching true labeled values. These results confirm the model’s proficiency and precision in TEM image processing and introduce a powerful tool for nanoscale image analysis. Our work sets a new standard for lightweight and efficient TEM segmentation models, paving the way for future advancements in nanotechnology research.
Numerical study of transition hydraulic jumps in different types of stilling basins using lattice Boltzmann methods
Authors: Gou Wenjuan , Shen Zhengzhong
Published: November 2024

Transition hydraulic jumps, also known as low-Froude number jumps, have been less studied compared to high Froude number jumps, despite their significance in high-discharge and low-head dams. A three-dimensional (3D) Lattice Boltzmann method simulation was conducted to investigate submerged transition hydraulic jumps in both normal and expanded stilling basins, focusing on turbulent flow characteristics such as velocity fields, vorticity features, pressure fluctuations, and coherent structures. In expanded basins, two symmetric separated rollers were observed, with the rollers detaching from the submerged jump as the width of basin increased. The length of submerged roller in normal basins is observed as Lr/Ht = 6.19, while it is decreased to Lr/Ht = 4 in expanded basins because of the occurrence of roller lateral diffusion toward sidewalls. The transition of vortex structures from y- to z-vortical was analyzed, and three-dimensional shear layers are captured using the iso-surface of vorticity magnitude ω = 6.5. To further describe the internal structure of turbulence within the transition hydraulic jump, the coherent flow structures are qualitatively examined using the Ω criterion that is the third generation of vortex identification technique. Pressure fluctuations in low-Froude number stilling basins, described using root mean square (RMS), are first presented. High patches of RMS are found in the flow fields and at the bottom of basins, and it is qualitatively noted that shear effects make great contributions to the pressure fluctuations. Distribution of bottom pressure fluctuation RMS in different types of basin was also analyzed. The peak RMS value occurs at the ogee region of the weir, specifically at x/L = −0.2, and it is mainly affected by the width of expansion. Bottom pressure fluctuation RMS decreases in the following order: Normal, 5 m gradual expansion, 10 m gradual expansion, 5 m sudden expansion, and 10 m sudden expansion, due to the lateral diffusion of rollers toward sidewalls. This research introduces an innovative numerical simulation approach to studying pressure fluctuations, offering valuable insights for hydraulic engineering applications.
Neural network-assisted model of interfacial fluids with explicit coarse-grained molecular structures
Authors: Ma Shuhao , Li Dechang , Li Xuejin , Hu Guoqing
Published: November 2024

Interfacial fluids are ubiquitous in systems ranging from biological membranes to chemical droplets and exhibit a complex behavior due to their nonlinear, multiphase, and multicomponent nature. The development of accurate coarse-grained (CG) models for such systems poses significant challenges, as these models must effectively capture the intricate many-body interactions, both inter- and intramolecular, arising from atomic-level phenomena, and account for the diverse density distributions and fluctuations at the interface. In this study, we use advanced machine learning techniques incorporating force matching and diffusion probabilistic models to construct a robust CG model of interfacial fluids. We evaluate our model through simulations in various settings, including the water–air interface, bulk decane, and dipalmitoylphosphatidylcholine monolayer membranes. Our results show that our CG model accurately reproduces the essential many-body and interfacial properties of interfacial fluids and proves effective across different CG mapping strategies. This work not only validates the utility of our model for multiscale simulations, but also lays the groundwork for future improvements in the simulation of complex interfacial systems.
A radius and minimum velocity Jensen model for far wake distribution prediction of tidal stream turbine
Authors: Wei Beibei , Yang Dingding , Wang Tianzhen , Zhu Bihong
Published: November 2024

The rational layout of tidal stream turbines (TSTs) is beneficial for making full use of tidal stream energy. It is essential to consider the wake radius and velocity distribution for determining the spacing between the TSTs. The wake is primarily affected by the turbulence intensity. The attenuation of turbulence results in the non-linear expansion of the wake. Additionally, the high turbulence in the near wake region inhibits the velocity deficit, which is more evident under high ambient turbulence intensity. Therefore, a radius and minimum velocity Jensen (RMV-Jensen) model is proposed to predict the wake radius and the wake velocity distribution downstream of a TST. The RMV-Jensen model consists of a radius block (R-Block) and a minimum velocity block (MV-Block). The R-Block is a piecewise exponential function based on the turbulence attenuation in the wake region, accurately describing the change of the wake expansion coefficient. The MV-Block is a wake minimum velocity model, and the inhibitory effect of turbulence on velocity deficit is considered for the first time. The RMV-Jensen model is applied to predict the wake distribution in the Zhoushan sea area. The prediction accuracy of the RMV-Jensen model is improved by 10%–20% compared to that of the classical Jensen model, according to the experimental results.
Three-dimensional elastic Rayleigh–Taylor instability at the cylindrical interface
Authors: Zeng R. H. , Wang Q. Y. , Sun Y. B. , Zhu S. L.
Published: November 2024

This paper presents a linear analysis of elastic Rayleigh–Taylor instability at both cylindrical column and cylindrical shell interfaces. By considering the rotational part of the disturbance flow field, an exact solution is derived, revealing that the most unstable mode is two-dimensional in the cross section. As the column radius decreases, the maximum growth rate increases, while the corresponding azimuthal wave number decreases incrementally until it reaches 1. Thinning the cylindrical shell is found to be a destabilizing effect, leading to an increase in both the cutoff wave number and the most unstable azimuthal wave number. The maximum growth rate usually increases as the shell becomes thinner, except in cases with small radii where feedthrough effects occur. For thin shells with small radii, the cutoff axial wave number is determined by the radius rather than the shell thickness. Comparisons between the growth rates derived from the potential flow theory and the exact solution show significant discrepancies in cylindrical shells, mainly due to substantial deviations in the cutoff wave number.
Ground tests for a future space experiment: Evaporation rates through a centimetric square chimney by vapor interferometry and simulation
Authors: Parimalanathan Senthil Kumar , Rednikov Alexey , Behle Robin Maximilian , Gambaryan-Roisman Tatiana , Colinet Pierre
Published: November 2024

In this paper, results of preparatory tests for a space experiment “Marangoni in Films” on board International Space Station are reported. The setup is thermalized at a setpoint temperature so that (thermal) Marangoni convection is exclusively a result of evaporative cooling of the film, here composed of a Hydrofluoroether (HFE)-7100, evaporating into nitrogen at a given setpoint pressure. The present paper is entirely devoted to the evaporation rates, whereas the Marangoni convection itself will be analyzed in future studies. Apart from the temperature and nitrogen pressure, various setpoints for the initial relative saturation in HFE-7100 vapor are explored. A special design of the test cell with a square chimney surrounding a square opening of the liquid layer permits to largely stabilize the evaporation rates during a longest-lasting middle stage (beyond the initial transients and the final film dry-out). In addition, it facilitates the use of vapor (digital-holographic) interferometry for measuring the evaporation rates, the results of which are compared with independent measurements by means of the pressure evolution within our sealed cell of a fixed volume. An excellent agreement is found before the final dry-out stage for all setpoint parameter combinations tested. The study is accompanied by numerical finite-element simulations in an axisymmetrized geometry, neglecting a possible influence of the Marangoni convection and verifying certain premises used in interferometric post-processing. Even if the simulation results might somewhat over-/underpredict in each particular case, the overall dependence of the evaporation rate on the setpoint parameters is well reproduced and the role of the buoyancy convection is thereby explored.
Sedimentation of short-lived fluid-solid suspensions
Authors: Girolami Laurence , Risso Frédéric , Amin Ahmad , Rousseau Loïc , Bondesan Andrea , Bonelli Stéphane
Published: November 2024

In this study, we propose a particle sedimentation/aggradation law for homogeneous concentrated suspensions. This law, valid in the Stokes flow regime, can be used to describe the sedimentation process observed in short-lived rapid flows, developed at high Reynolds numbers, that can be described as low-viscosity quasi-parallel flows traveling at constant velocity and that progressively sediment during the dominant phase of transport to leave a triangular or trapezoidal deposit of constant slope. The particle aggradation velocity can thus be predicted from the product of the mean flow velocity and the deposit slope and turns out to be roughly similar to that measured from static suspensions of the same concentration, provided that the flow Reynolds number, based on the mean flow velocity, the fluid properties, and the particle size, remains inferior to a few hundred, such as the mixture agitation cannot disturb the sedimentation process. These important results provide the possibility of describing the depositional dynamics during the final stage of extreme events, as well as to infer the mixture rheology, from physical parameters that can be easily measured in the field.
Elucidating the intrinsic relationship between redox properties of CeO2 and CH4 oxidation activity: A theoretical perspective
Authors: Li Juan , Zhou Shuyun , Li Peng , Zhou Shulan , Wan Qiang , Guo Hua , Lin Sen
Published: November 2024

Methane (CH4) oxidation is an important reaction to reduce the greenhouse effect caused by incomplete combustion of CH4. Here, we explored the mechanism of CH4 oxidation catalyzed by CeO2 and Ni-doped CeO2, focusing on the redox properties of these catalyst surfaces, using density functional theory (DFT). We found that the barriers for CH4* activation and H2O* formation are correlated with the surface redox capacity, which is enhanced by Ni doping. Furthermore, the complete reaction mechanism is explored by DFT calculations and microkinetic simulations on bare and Ni-doped CeO2 surfaces. Our calculations suggest that the doping of Ni leads to a much higher overall reactivity, due to a balance between the CH4* activation and H2O* formation steps. These results provide insights into the CH4 oxidation mechanism and the intrinsic relationship between redox properties and the activity of CeO2 surfaces.
Data-driven prediction of flow fields in a needle-ring-net electrohydrodynamic pump system
Authors: Wang Lu-Yao , Cai Ru-Xian , Chen Wen , Zhang Fan , Yan Wei-Cheng
Published: November 2024

In this paper, a data-mechanism hybrid modeling method for efficiently obtaining an electrohydrodynamic flow field is proposed. First, a backpropagation (BP) model with high accuracy is trained to get the value of essential parameter q0 for the mechanism simulation of flow fields. Subsequently, the mechanism model is used to generate a database for flow field reconstruction. Three machine learning algorithms, namely, BP neural network, random forest regression (RFR), and convolutional neural network (CNN), are employed to predict and reconstruct the flow behaviors of a needle-ring-net electrohydrodynamic pump. The RFR model demonstrates higher accuracy and precision in predicting velocity and pressure in the flow field compared to the BP and CNN models. The use of machine learning models for flow field prediction can significantly reduce the computational time while maintaining the computational accuracy. Additionally, an analysis assessing the impact of varying dataset sizes on the prediction accuracy of the model is conducted. The results indicate that the size of the dataset significantly influences the model predictive performance. Specifically, larger datasets are suggested to enhance both the accuracy and the generalization capabilities of the model. This observation highlights the critical role of dataset size in optimizing the performance of machine learning models for predictive tasks in engineering applications. These results offer important references for improving the design and optimization of electrohydrodynamic pumps.
Hydrodynamics investigation of a three-dimensional fish swimming in oblique flows by a ghost cell method
Authors: Shi Fulong , Xin Jianjian , Jin Qiu , Yang Yang , Wan Ling
Published: November 2024

Fish in nature can encounter various flow environments. This paper numerically simulated a 3D (three-dimensional) carangiform fish swimming in oblique flow. The numerical model adopts a robust ghost cell method with graphics processing unit acceleration. The dynamic performance and the 3D wake evolutions are discussed under different Strouhal numbers and attack angles. It is found that the thrust along the swimming direction would get enhanced with more energy consumption as the Strouhal number (St) rises. The attack angle can get the similar but less significant effect. Also, the stall angle of θ = 40° is approximately determined, which is independent of the Strouhal number. However, the flexible deformation can reduce the adverse effects of the stall. In terms of the wake structures, they are transitioned from the two rows of vortex streets at St = 0.2 to the three rows at St = 0.6, and even to the four rows at St = 1. The connected oblique vortex ring rows induced by the undulating caudal fin contributes to the thrust and lateral forces dominantly. As the St rises, the vortex ring rows is transformed from the typical von Karman vortex streets to the reverse one, indicating the generation of thrust. The slender, parallel vortex contrails are caused by the detachment of leading-edge vortices (LEVs), and they induce the high-order harmonic components in force coefficients. The oblique angle of the vortex rings grows with the Strouhal number, while it is hardly affected by the attack angle. As the attack angle grows, the wake is turned from the disconnected hairpin vortices to the intertwined vortex rings and losses the spanwise symmetry. Moreover, the reattachment of the LEV is not observed after the stall angle.
A novel method measuring the clustering of particles: Pseudo-gravitation
Authors: Wang Xiangjun , Zhang Wen , Wan Minping
Published: November 2024

A novel pseudo-gravitation method is proposed to quantitatively measure the degree of the preferential concentration of particles in turbulent flows, where virtual gravitations are employed to evaluate the extent of particle accumulation. The pseudo-gravitation method introduces a nondimensional “Gravitation Index” (GĨ) to estimate the local concentration of particles and a nondimensional “Global Gravitation Index” (GGĨ) to quantify the degree of particle clustering across the whole domain. This method can effectively characterize both the Eulerian and Lagrangian properties of the particle preferential concentration, without the need for any predefined artificial parameters. Additionally, it is not only robust to the variation in the number of particles but also sensitive to the change in physical parameters, such as the Stokes number (St) and Reynolds number (Re).
Impacts of jet inflow on hydrodynamic performance and waste removal efficiency in recirculating aquaculture system aquaculture tanks based on prototype experiments
Authors: Ji Xinran , Tu Zonghai , Wang Daoru , Zou Li , Bian He , Li Xu , Ma Qiaofeng
Published: November 2024

Although scaled physical models and numerical simulations have been employed to study the hydrodynamic performance of recirculating aquaculture system (RAS) aquaculture tanks, there remains a paucity of prototype experiments that fully reflect the actual hydrodynamic performance. In this study, a prototype experiment was conducted on RAS aquaculture tanks, utilizing advanced image processing techniques specifically adapted to the prototype scale. This study focused on impacts of various jet inflow parameters, including jet inflow angle (0°, 10°, 20°, 30°, 40°, 45°, 50°, 60°, and 70°), jet inflow rate (150, 180, 210, and 240 l·min−1), jet inflow area (942 and 1884 mm2), and jet inflow location (curved wall and straight wall), on the hydrodynamic performance and waste removal efficiency of RAS aquaculture tanks. The results demonstrated the hydrodynamic performance—specifically average flow velocity, flow field uniformity, and the extent of low-velocity zones conjointly determining waste removal efficiency. The curved wall proved to be the optimal location for inflow pipe placement, while a 45° jet angle yielded the best balance between hydrodynamic performance optimization and waste removal efficiency. Furthermore, reducing the inlet area significantly improved average flow velocity and flow uniformity, whereas variations in inlet flow rate had minimal impact on these factors. Supported by these compelling findings, this study offers theoretical insight and practical guidance for achieving efficient aquaculture in RAS, thereby contributing to the advancement of sustainable aquaculture practices.
Experimental study of bubble cavity effect on ballistic characteristics of vehicle entering water
Authors: Zhang Zhifan , Shao Yan , Xie Yujie , Wang Dapeng , Zhang Qi , Sun Tiezhi , Zhang Guiyong
Published: November 2024

The water-entry process of a vehicle is a typical fluid–structure interaction problem. When the vehicle enters the water at a certain angle, asymmetric loads caused by the asymmetric wetted part can significantly affect its ballistic characteristics and increase the risk of instability. A bubble cavity near free surface can reconstruct the wave surface condition, which makes the vehicle enter the water at a larger angle. This paper experimentally investigates the bubble-cavity effect on the stability of the vehicle during its water-entry process. The results show that the existence of the cavity can effectively improve the stability of underwater motion trajectory of the vehicle, with the angular deviation decreased by 85.7% compared with that in the calm water. In addition, it is found that the existence of the bubble cavity significantly increases the closure speed of the cavitation bubble at the tail of the vehicle after water entry.
1T′-MoSP monolayer as an anode material for sodium-ion batteries with ultrahigh storage capacity and ultralow diffusion barrier
Authors: Tang Meng , Zhang Wenyuan , Liu Zhixiao , Yang Guochun , Deng Huiqiu
Published: November 2024

Sodium-ion batteries (SIBs) have gained significant attention due to the abundant availability and low cost of sodium. However, the search for high-performance anode materials remains a critical challenge in advancing SIB technology. Based on first-principles swarm-intelligence structure calculations, we propose a metallic 1T′-MoSP monolayer as an anode material that offers a remarkably high storage capacity of 1011 mA h g−1, an ultralow barrier energy of 0.04 eV, and an optimal open-circuit voltage of 0.29 V, ensuring high rate performance and safety. Additionally, the monolayer presents favorable wettability with commonly used SIB electrolytes. Even after adsorbing three-layer Na atoms, the 1T′-MoSP monolayer retains its metallic nature, ensuring excellent electrical conductivity during the battery cycle. These desirable properties make the 1T′-MoSP monolayer a promising anode material for SIBs.
On the unsteady flow dynamics of a planar-plug nozzle with a semi-extended cowl
Authors: Bharathwaj M. , Krishna Talluri Vamsi , Nanda Soumya R. , Karthick S. K. , Sugarno Mohammed Ibrahim
Published: November 2024

Experiments are conducted with a planar-plug nozzle having a 50% cowl extension, operating in over-expanded nozzle pressure ratios ζ=[p0/pa]=2,3, and 4 to study the unsteady flow dynamics on the ramp surface and acoustic features of the flow on the far-field as influenced by the partial cowl extension. Steady pressure measurements and high-speed Schlieren imaging indicated that the flowfield on the ramp surface has shock-boundary layer and shock-shear layer interactions. The three-dimensional flow features on the ramp surface are studied based on oil flow visualization. A proper orthogonal decomposition based modal analysis of the Schlieren images is conducted to identify the dominant spatiotemporal characteristics. Unsteady pressure fluctuations on the ramp surface acquired simultaneously with microphone measurements are analyzed to infer the jet unsteadiness and noise source. Investigations across different ζ reveal the presence of both incipient and complete separation of the jet flow on the ramp. Moreover, the cowl extension delays the ζ at which the dominant screech and jet flapping occur.
A turbulence model: Second-order temporal accuracy
Authors: Zhang Yuanshuang , Huang Pengzhan
Published: November 2024

This paper develops the defect-deferred correction method of finite element discretization to solve a turbulence model. The method consists of two phases: (1) implementing an artificial viscosity term as a defect step and (2) applying a correction strategy. This method can not only achieve second-order accuracy in time but also simulate small viscosity problem. Moreover, the stability and convergence of the defect step and the deferred correction step are proven, respectively. Finally, we perform several numerical examples to validate the theoretical analysis and illustrate the effectiveness of the proposed method.
Automatic construction and verification algorithm for smart contracts based on formal verification
Authors: Xie Rui , Zhong Xuejiao , Chen Xin , Xu Shaohui , Yu Haiyang , Guo Xinyuan
Published: November 2024

As an emerging technology, blockchain demonstrates strong potential for applications in digital finance. As a core component of blockchain, the security and reliability of smart contracts is crucial. To ensure the high reliability of smart contracts, this study employs formal construction and verification techniques based on game theory. Initially, the profit function is defined using distortion techniques, and a game model for supply chain participation is designed. However, the equilibrium solution of the two-party game does not represent the optimal solution for the supply chain system. Therefore, the study introduces third-party participation to optimize the equilibrium solution. Finally, a probability model detection method is used to verify the constructed smart contract model. The results show that the supply chain model, analyzed through formal methods, has attributes consistent with theoretical analysis. Consequently, the research on automatic construction and verification algorithms for smart contracts based on formal verification proves to be effective and feasible in practical applications.
External drivers of changes in wildland firefighter safety policies and practices
Authors: Cordner Alissa
Published: November 2024

Background Firefighter safety is a top priority in wildland fire response and management. Existing explanations emphasise how land management agency initiatives to change organisational culture, usually inspired by fatality incidents, contribute to changes both in formal safety policies and informal safety practices. Aims This paper identifies external factors that lead to changes in wildland firefighter safety policies and practices. Methods This paper uses qualitative data from a long-term ethnographic research project. Data include detailed fieldnotes, semi-structured interviews, and agency documents, which were systematically coded and thematically analysed. Key results In addition to the triggering effects of fatality incidents and agency initiatives to change organisational culture, external factors also directly impact the development of firefighter safety policies and practices. These include sociodemographic, material, political, and social-environmental factors. Conclusions Identifying and understanding the influence of multi-scalar external factors on firefighter safety is essential to improving safety outcomes and reducing firefighters’ exposure to hazards. Implications Attention to and recognition of external factors is valuable for fire managers and practitioners, whose work is influenced and constrained by meso- and macro-level factors. The framework presented in this paper would be useful in understanding other important aspects of wildland fire management.
V1 neurons are tuned to perceptual borders in natural scenes
Authors: Papale Paolo , Zuiderbaan Wietske , Teeuwen Rob R. M. , Gilhuis Amparo , Self Matthew W. , Roelfsema Pieter R. , Dumoulin Serge O.
Published: November 2024

The visual system needs to identify perceptually relevant borders to segment complex natural scenes. The primary visual cortex (V1) is thought to extract local borders, and higher visual areas are thought to identify the perceptually relevant borders between objects and the background. To test this conjecture, we used natural images that had been annotated by human observers who marked the perceptually relevant borders. We assessed the effect of perceptual relevance on V1 responses using human neuroimaging, macaque electrophysiology, and computational modeling. We report that perceptually relevant borders elicit stronger responses in the early visual cortex than irrelevant ones, even if simple features, such as contrast and the energy of oriented filters, are matched. Moreover, V1 neurons discriminate perceptually relevant borders surprisingly fast, during the early feedforward-driven activity at a latency of ~50 ms, indicating that they are tuned to the features that characterize them. We also revealed a delayed, contextual effect that enhances the V1 responses that are elicited by perceptually relevant borders at a longer latency. Our results reveal multiple mechanisms that allow V1 neurons to infer the layout of objects in natural images.
The role of astrocytes in depression, its prevention, and treatment by targeting astroglial gliotransmitter release
Authors: Duarte Yorley , Quintana-Donoso Daisy , Moraga-Amaro Rodrigo , Dinamarca Ivanka , Lemunao Yordan , Cárdenas Kevin , Bahamonde Tamara , Barrientos Tabita , Olivares Pedro , Navas Camila , Carvajal Francisco J. , Santibánez Yessenia , Castro-Lazo Raimundo , Paz Meza María , Jorquera Ramon , Gómez Gonzalo I. , Henke Marina , Alarcón Rodrigo , Gabriel Laureen A. , Schiffmann Susanne , Cerpa Waldo , Retamal Mauricio A. , Simon Felipe , Linsambarth Sergio , Gonzalez-Nilo Fernando , Stehberg Jimmy
Published: November 2024

The role of ventral hippocampus (vHipp) astroglial gliotransmission in depression was studied using chronic restraint stress (CRS) and chronic unpredictable mild stress (CUMS) rodent models. CRS increased Cx43 hemichannel activity and extracellular glutamate levels in the vHipp and blocking astroglial Cx43 hemichannel-dependent gliotransmission during CRS prevented the development of depression and glutamate buildup. Moreover, the acute blockade of Cx43 hemichannels induced antidepressant effects in rats previously subjected to CRS or CUMS. This antidepressant effect was prevented by coinjection of glutamate and D-serine. Furthermore, Cx43 hemichannel blockade decreased postsynaptic NMDAR currents in vHipp slices in a glutamate and D-serine-dependent manner. Notably, chronic microinfusion of glutamate and D-serine, L-serine, or the NMDAR agonist NMDA, into the vHipp induced depressive-like symptoms in nonstressed rats. We also identified a small molecule, cacotheline, which blocks Cx43 hemichannels and its systemic administration induced rapid antidepressant effects, preventing stress-induced increases in astroglial Cx43 hemichannel activity and extracellular glutamate in the vHipp, without sedative or locomotor side effects. In conclusion, chronic stress increases Cx43 hemichannel-dependent release of glutamate and D-/L-serine from astrocytes in the vHipp, overactivating postsynaptic NMDARs and triggering depressive-like symptoms. This study highlights the critical role of astroglial gliotransmitter release in chronic stress-induced depression and suggests it can be used as a target for the prevention and treatment of depression.
Extremely rapid, yet noncatastrophic, preservation of the flattened-feathered and 3D dinosaurs of the Early Cretaceous of China
Authors: MacLennan Scott A. , Sha Jingeng , Olsen Paul E. , Kinney Sean T. , Chang Clara , Fang Yanan , Liu Jun , Slibeck Bennett B. , Chen Elaine , Schoene Blair
Published: November 2024

Northeast China’s Early Cretaceous Yixian Formation preserves spectacular fossils that have proved extraordinarily important in testing evolutionary hypotheses involving the origin of birds and the distribution of feathers among nonavian dinosaurs. These fossils occur either flattened with soft tissue preservation (including feathers and color) in laminated lacustrine strata or as three-dimensional (3D) skeletons in “life-like” postures in more massive deposits. The relationships of these deposits to each other, their absolute ages, and the origin of the extraordinary fossil preservation have been vigorously debated for nearly a half century, with the prevailing view being that preservation was linked to violent volcanic eruptions or lahars, similar to processes that preserved human remains at Pompeii. We present high-precision zircon U-Pb geochronology from cores and outcrops, demonstrating that Yixian Formation accumulation rates are more than an order of magnitude higher than usually estimated. Additionally, we provide zircon provenance and sedimentological data from 3D dinosaur fossils, which imply that their death and burial occurred in collapsed burrows, rather than via a catastrophic volcanogenic mechanism. In the studied area, the three principal fossil-rich intervals of the Yixian occur as a cyclic sequence that correspond to periods of high precipitation. Using Bayesian–Markov Chain Monte Carlo approaches, we constrain the total duration of the sequence to less than ~93,000 y and suggest that climatic precession paced the expression of these cyclic sediments. Rather than representing multiple, Pompeii-like catastrophes, the Yixian Formation is instead a brief snapshot of normal life and death in an Early Cretaceous continental community.
Juvenile hormone as a key regulator for asymmetric caste differentiation in ants
Authors: Li Ruyan , Dai Xueqin , Zheng Jixuan , Larsen Rasmus Stenbak , Qi Yanmei , Zhang Xiafang , Vizueta Joel , Boomsma Jacobus J. , Liu Weiwei , Zhang Guojie
Published: November 2024

Caste differentiation involves many functional traits that diverge during larval growth and metamorphosis to produce adults irreversibly adapted to reproductive division of labor. Investigating developmental differentiation is important for general biological understanding and has increasingly been explored for social phenotypes that diverge in parallel from similar genotypes. Here, we useMonomorium pharaonisants to investigate the extent to which canalized worker development can be shifted toward gyne (virgin-queen) phenotypes by juvenile hormone (JH) treatment. We show that excess JH can activate gyne-biased development in workers so that wing-buds, ocelli, antennal and genital imaginal discs, flight muscles, and gyne-like fat bodies and brains emerge after pupation. However, ovary development remained unresponsive to JH treatment, indicating that JH-sensitive germline sequestration happens well before somatic differentiation. Our findings reveal important qualitative restrictions in the extent to which JH treatment can redirect larval development and that these constraints are independent of body size. Our findings corroborate that JH is a key hormone for inducing caste differentiation but show that this process can be asymmetric for higher colony-level germlineversussomatic caste differentiation in superorganisms as defined a century ago by Wheeler. We quantified gene expression changes in response to JH treatment throughout development and identified a set of JH-sensitive genes responsible for the emergence of gyne-like somatic traits. Our study suggests that the gonadotropic role of JH in ovary maturation has shifted from the individual level in solitary insects to the colony level in an evolutionary-derived and highly polygynous superorganism like the pharaoh ant.