bluuebunny/crossref_metadata_2025 huggingface dataset:
Dynamics of a tail cavity induced by the vertical motion of an underwater vehicle
Authors: Liu Junliang , Xiao Wei , Yao Xiongliang , Qu Zhaoyu , Lu Chaoxu
Published: February 2025

This study investigates the dynamics of the tail cavity induced by an underwater vehicle. The morphological evolution and pressure characteristics of the tail cavity are simulated using a numerical model based on the boundary integral method. The numerical model is validated against tail cavity experiments conducted by us. The mechanisms of certain tail cavity behaviors during the cavity evolution process are explored from the perspective of pressure, and the pressure characteristics of the flow field at different vertical and radial positions are obtained. Then, the influence of the initial vehicle velocity and the initial cavity pressure parameter on cavity fracture and cavity jet are studied. In terms of the fracture behavior, we find that the fracture location of the tail cavity and the length of the sub-cavities undergo abrupt changes as the initial vehicle velocity and cavity pressure parameter vary. The secondary necking of the tail cavity is considered as the primary cause of these abrupt changes. In terms of the jetting behavior, we find that the governing parameters impact the collapse extent of the sub-cavities at the moment of jet impact. Finally, the variation characteristics of the jet kinetic energy of the attached sub-cavity and the residual sub-cavity at this moment are quantitatively studied within the selected parameter space.
Topological cascade of quantum Borromean rings
Authors: Guan Hao , Zuccher Simone , Liu Xin
Published: February 2025

The evolution and the topological cascade of quantum vortices forming Borromean rings are studied for the first time. The initial configuration of the system is given by three elliptical planar loops linked together, and the evolution is governed by the numerical implementation of the Gross–Pitaevskii equation. It is found that the topological cascade is not unique, but it depends crucially on the initial geometric configuration. Quantum vortices undergo a series of spontaneous reconnections, resulting in various degenerative pathways characterized by different topology and structural complexity triggered by the different inclination of one of the initial ellipses. Typical decaying routes are given by the successive creation of a Whitehead link, a connected sum of two Hopf links, a trefoil knot, a Hopf link, and the final formation of unknotted, unlinked loops. By structural complexity analysis, we show that the generic trend of the vortex decay goes through a series of topological simplifications, resulting in the formation of small-scale planar loops (rings). During the later stage of evolution, the inverse cascade and topological cycles involving the interaction of unknotted loops become more common, remaining sub-dominant to the overall topological simplification process. These results pave the way to investigate the fundamental relations between structural complexity and energy contents.
Study on pressure field characteristics of high specific speed axial flow pump under full working conditions based on wavelet transform
Authors: Hu Chongyang , Zhang Xiaowen , Shen Wenzhong , Liu Haiyu , Tang Fangping , Yan Bipeng
Published: February 2025

Axial flow pumps are widely used in ship jet propulsion units and coastal plain pumping stations. In the actual operation process, axial flow pumps need to operate in extreme working conditions, in order to explore the safety and stability of axial flow pumps operating under special working conditions, this paper adopts a method that combines model experiment and numerical simulation. A full-condition model experiment of the axial flow pump section (AFPS) is carried out on the high-precision axial flow pump system test platform. Meanwhile, a simulation model predicting the full characteristics of the AFPS is constructed. Numerical simulations are carried out for the AFPS at 31 flow rates, and the hydrodynamic characteristics of the AFPS are investigated in depth in 8 conditions, which reveals the internal evolution of the AFPS under the synergistic influence of the water flow direction and the impeller steering in the whole quadrant. The traditional analysis method Fast Fourier Transform is difficult to analyze the dynamic changes of such a complex non-smooth signal in the flow field under full operating conditions of axial flow pumps. In this paper, the wavelet transform is used to analyze the pressure pulsation signals in the time–frequency two-dimensional plane at multiple scales, to capture the time–frequency subtle changes, and the cross wavelet transform reveals the signal relationships at different locations, which comprehensively and deeply reveals the pressure pulsation spatiotemporal transformation characteristics of the pump section. The results show that when the water flow direction is opposite to the rotation direction of the impeller, the internal flow of the AFPS is disordered and the pressure pulsation is strong. Except for the forward flow turbine condition when the impeller is rotating forward (OP4) condition, the wavelet energy at the impeller inlet is greater than that at the impeller outlet with a maximum difference of eight times (OP5). The pressure pulsation between the inlet and outlet of the impeller has a large number of common frequencies.
Energy evolution in the Kármán vortex street of compressible flow around a circular cylinder
Authors: Tao Yizhou , Qu Junwang , Gao Shulong , Qiu Xiang , Zhang Xinlong , Liu Yulu
Published: February 2025

In this study, compressible flow around a circular cylinder is investigated at Reynolds number (Re = 50, 100, 150, 200) and Mach number (Ma = 0.1, 0.3, 0.5, 0.6) using direct numerical simulation. The energy evolution and vortex dynamics within the Kármán vortex street are discussed, with the case of Re = 150 and Ma = 0.5 serving as a representative example. The kinetic energy evolution involves three key regions: region E supplies energy to vortices, region I causes vortices deflection and expansion, and region S promotes vortex separation, with kinetic energy transport dominating the variation in kinetic energy. Through time-averaged statistical results, we divide the near wake into several zones, each revealing the impact of non-uniformity, unsteady effects, and viscous forces on energy redistribution. Unsteady effects are predominant in the main vortex passage, while non-uniformity prevails in areas swept by the vortex head and tail. Furthermore, the effects of Reynolds numbers and Mach numbers on vortex dynamics and energy evolution are further explored. The results reveal that as the Re increases, the strength of vortices and vortex-shedding frequency are enlarged, leading to an enhanced kinetic energy transport and energy redistribution. However, variations in Mach number have minimal impact on these processes. At higher Re, the unsteady effects become more pronounced, and low-energy regions shift closer to the cylinder.
Wall temperature effects on scaling law in high-temperature supersonic turbulent channel flows
Authors: Zhao Shuo , Lin Pei-Feng , Chen Xiao-Ping
Published: February 2025

Direct numerical simulations of temporally evolving high-temperature supersonic turbulent channel flows are performed at Mach number 3 and Reynolds number 4888. Air is assumed to behave as a five-species mixture and chemical equilibrium assumption. Five isothermal wall temperatures are in the range of 1733.2–4100.0 K. The results show that the mixture components undergo strong dissociation and recombination reactions along the channel for all wall temperature conditions. The wall temperature does not alter the original symmetry of fluctuating velocity and equilibrium species. The intermittence of turbulence is insensitive to the wall temperature, and the intermittence of equilibrium species enhances with the wall temperature increased. The scaling law derived and validated for calorically perfect gas still hold or can be generalized for chemical equilibrium assumption. Good linear relationship is observed in the extended self-similarity, which is more obvious than the velocity structure function. The influence of wall temperature on scaling law near the wall is more significant than that at the centerline. As the wall temperature increases, the relative scaling exponents of the generated components near the wall are gradually approaching to the theory proposed by She and Leveque.
Method for evaluating the adsorption/desorption equilibrium of methane in coal and its impact on desorption hysteresis loops
Authors: Zhai Yingquan , Song Dangyu , Li Yunbo , Pan Jienan , Ji Xiaofeng
Published: February 2025

The isothermal adsorption of methane in coal is essential for understanding the adsorption mechanism. The accuracy of equilibrium adsorption measurements directly impacts the reliability and scientific validity of the experimental results. This study conducted high-pressure methane isothermal adsorption/desorption experiments on coal samples with varying pore structures to investigate the impact of the adsorption equilibrium evaluation method on the results. The study found that using the fixed-time method to determine the equilibrium adsorption volume can lead to significant errors, particularly for samples with complex fluctuations in the adsorption/desorption curves. Based on the observed behavior of the adsorption curve, the slope method was proposed to determine the equilibrium adsorption volume. This method first smooths the raw data to extract the overall trend and then determines the equilibrium adsorption volume based on changes in the slope. Comparing the results of the two methods revealed that the slope method effectively addressed anomalies in the adsorption/desorption curves and significantly improved the fitting of the Langmuir model. For instance, the goodness of fit for the Shenmu Mine column sample increased from 0.7803 to 0.9960. Additionally, hysteresis analysis revealed that the hysteresis index of the slope method was significantly lower than that of the fixed-time method, indicating that the accuracy of the experimental results plays a critical role in desorption hysteresis.
Freezing of an acoustically levitated drop: From liquid disk to ice ring
Authors: Zhang Xiaoqiang , Wang Yuhan , Liu Kangqi , Chen Hongyue , Ji Xiaoliang , Chen Ningli , Wang Zhijun , Wang Nan , Zang Duyang
Published: February 2025

Drop freezing plays an important role in industries ranging from food and materials to biomedicine, but the contact between drops and substrates is unavoidable. The contact effect has great influence on the nucleation and growth of ice. To eliminate the wall effect on drop freezing, we studied the freezing of liquid drops under container-free conditions by combining the sound field and temperature field. The levitated drops exhibited varied frozen morphologies, such as ice saucer, ice cake, and ice ring, depending on their initial shapes. For a levitated liquid disk, it eventually freezes to form a levitated ice ring, which is caused by the atomization rupture of its central liquid film. In addition, we accomplished the landing–lifting manipulation of the frozen drops by controlling the sound field. Our work highlights the coupling effects between thermodynamically driven phase transitions and mechanically driven drop dynamics involved in acoustic levitation. The investigation of levitated drop freezing contributes to a in-depth understanding of the phase transition process and dynamic behavior of fluids in a container-free environment, and also inspires and expands new methods for the fabrication of ring-shaped materials.
Evolutionary rewiring of the dynamic network underpinning allosteric epistasis in NS1 of the influenza A virus
Authors: Gonzales James E. , Kim Iktae , Bastiray Abhishek , Hwang Wonmuk , Cho Jae-Hyun
Published: February 2025

Viral proteins frequently mutate to evade host innate immune responses, yet the impact of these mutations on the molecular energy landscape remains unclear. Epistasis, the intramolecular communications between mutations, often renders the combined mutational effects unpredictable. Nonstructural protein 1 (NS1) is a major virulence factor of the influenza A virus (IAV) that activates host PI3K by binding to its p85β subunit. Here, we present a deep analysis of the impact of evolutionary mutations in NS1 that emerged between the 1918 pandemic IAV strain and its descendant PR8 strain. Our analysis reveals how the mutations rewired interresidue communications, which underlie long-range allosteric and epistatic networks in NS1. Our findings show that PR8 NS1 binds to p85β with approximately 10-fold greater affinity than 1918 NS1 due to allosteric mutational effects, which are further tuned by epistasis. NMR chemical shift perturbation and methyl-axis order parameter analyses revealed that the mutations induced long-range structural and dynamic changes in PR8 NS1, relative to 1918 NS1, enhancing its affinity to p85β. Complementary molecular dynamics simulations and graph theory-based network analysis for conformational dynamics on the submicrosecond timescales uncover how these mutations rewire the dynamic network, which underlies the allosteric epistasis. Significantly, we find that conformational dynamics of residues with high betweenness centrality play a crucial role in communications between network communities and are highly conserved across influenza A virus evolution. These findings advance our mechanistic understanding of the allosteric and epistatic communications between distant residues and provide insight into their role in the molecular evolution of NS1.
Urban groundwater supplies facing dual pressures of depletion and contamination in China
Authors: Sun Siao , Liu Hui , Konar Megan , Fu Guangtao , Fang Chuanglin , Huang Zhongwei , Li Guagndong , Qi Wei , Tang Qiuhong
Published: February 2025

Groundwater is essential to urban water supplies throughout the world, but we do not understand how quantity and quality issues may jeopardize the ability of cities to meet their water needs. Here, we present a national analysis of both quantity and quality challenges facing China’s urban groundwater supply security, using high-resolution groundwater depletion modeling and a recently compiled dataset detailing quality violations in drinking groundwater sources. We estimate that 180 cities (about half of the prefecture-level-and-above cities), accounting for 311 million urban residents, face at least one groundwater pressure between 2016 and 2021. Cities that face dual quantity and quality pressures pinpoints hotspots of intense groundwater threats— Specifically, 40 cities, mainly situated in Northeast China and the middle to lower reaches of the Yellow River, are exposed to dual groundwater pressures. The results highlight the interconnected and possibly mutually reinforcing nature of groundwater depletion and quality issues. The logistic regression models indicate that groundwater depletion and quality violations are associated with natural water endowment and anthropogenic factors. Particularly, drinking groundwater quality issues are clustered in relation to socioeconomic gaps, with larger, wealthier cities being less prone to such problems. We argue that securing drinking water sources in small and poor cities through integrated groundwater management and economic assistance should be an important national priority for achieving groundwater supply sustainability.
Poly(ADP-ribose) binding sites on collagen I fibrils for nucleating intrafibrillar bone mineral
Authors: Zecca Marco A. , Greer Heather F. , Müller Karin H. , Duer Melinda J.
Published: February 2025

Bone calcification is essential for vertebrate life. The mechanism by which mineral ions are transported into collagen fibrils to induce intrafibrillar mineral formation requires a calcium binding biopolymer that also has highly selective binding to the collagen fibril hole zones where intrafibrillar calcification begins, over other bone extracellular matrix components. Poly(ADP-ribose) (PAR) has been shown to be a candidate biopolymer for this process and we show here that PAR has high affinity, highly conserved binding sites in the collagen type I C-terminal telopeptides. The identification of these PAR–collagen binding sites gives insights into the chemical mechanisms underlying bone calcification and possible mechanisms behind pathologies where there is dysfunctional bone calcification.
Subfunctionalization and epigenetic regulation of a biosynthetic gene cluster in
Solanaceae
Authors: Priego-Cubero Santiago , Knoch Eva , Wang Zhidan , Alseekh Saleh , Braun Karl-Heinz , Chapman Philipp , Fernie Alisdair R. , Liu Chang , Becker Claude
Published: February 2025

Biosynthetic gene clusters (BGCs) are sets of often heterologous genes that are genetically and functionally linked. Among eukaryotes, BGCs are most common in plants and fungi and ensure the coexpression of the different enzymes coordinating the biosynthesis of specialized metabolites. Here, we report the identification of a withanolide BGC in
Physalis grisea
(ground-cherry), a member of the nightshade family (
Solanaceae
). A combination of transcriptomic, epigenomic, and metabolic analyses revealed that, following a duplication event, this BGC evolved two tissue-specifically expressed subclusters, containing several pairs of paralogs that contribute to related but distinct biochemical processes; this subfunctionalization is tightly associated with epigenetic features and the local chromatin environment. The two subclusters appear strictly isolated from each other at the structural chromatin level, each forming a highly self-interacting chromatin domain with tissue-dependent levels of condensation. This correlates with gene expression in either above- or below-ground tissue, thus spatially separating the production of different withanolide compounds. By comparative phylogenomics, we show that the withanolide BGC most likely evolved before the diversification of the
Solanaceae
family and underwent lineage-specific diversifications and losses. The tissue-specific subfunctionalization is common to species of the
Physalideae
tribe but distinct from other, independent duplication events outside of this clade. In sum, our study reports on an instance of an epigenetically modulated subfunctionalization within a BGC and sheds light on the biosynthesis of withanolides, a highly diverse group of steroidal triterpenoids important in plant defense and amenable to pharmaceutical applications due to their anti-inflammatory, antibiotic, and anticancer properties.
The endocannabinoid 2-arachidonoylglycerol is released and transported on demand via extracellular microvesicles
Authors: Straub Verena M. , Barti Benjamin , Tandar Sebastian T. , Stevens A. Floor , van Egmond Noëlle , van der Wel Tom , Zhu Na , Rüegger Joel , van der Horst Cas , Heitman Laura H. , Li Yulong , Stella Nephi , van Hasselt J. G. Coen , Katona István , van der Stelt Mario
Published: February 2025

While it is known that endocannabinoids (eCB) modulate multiple neuronal functions, the molecular mechanism governing their release and transport remains elusive. Here, we propose an “
on-demand release
” model, wherein the formation of microvesicles, a specific group of extracellular vesicles (EVs) containing the eCB, 2-arachidonoylglycerol (2-AG), is an important step. A coculture model system that combines a reporter cell line expressing the fluorescent eCB sensor, G protein-coupled receptor-based (GRAB)
eCB2.0
, and neuronal cells revealed that neurons release EVs containing 2-AG, but not anandamide, in a stimulus-dependent process regulated by protein kinase C, Diacylglycerol lipase, Adenosinediphosphate (ADP) ribosylation factor 6 (Arf6), and which was sensitive to inhibitors of eCB facilitated diffusion. A vesicle contained approximately 2,000 2-AG molecules. Accordingly, hippocampal eCB-mediated synaptic plasticity was modulated by Arf6 and transport inhibitors. The “
on-demand release
” model, supported by mathematical analysis, offers a cohesive framework for understanding eCB trafficking at the molecular level and suggests that microvesicles carrying signaling lipids in their membrane regulate neuronal functions in parallel to canonical synaptic vesicles.
Manipulating hydrogenation pathways enables economically viable electrocatalytic aldehyde-to-alcohol valorization
Authors: Yao Ze-Cheng , Chai Jing , Tang Tang , Ding Liang , Jiang Zhe , Fu Jiaju , Chang Xiaoxia , Xu Bingjun , Zhang Liang , Hu Jin-Song , Wan Li-Jun
Published: February 2025

Electrocatalytic reduction (ECR) of furfural represents a sustainable route for biomass valorization. Unfortunately, traditional Cu-catalyzed ECR suffers from diversified product distribution and industrial-incompatible production rates, mainly caused by the intricate mechanism−performance relationship. Here, we manipulate hydrogenation pathways on Cu by introducing ceria as an auxiliary component, which enables the mechanism switching from proton-coupled electron transfer to electrochemical hydrogen-atom transfer (HAT) and thus high-speed furfural-to-furfuryl alcohol electroconversion. Theoretical and kinetic analyses show that oxygen-vacancy-rich ceria delivers an efficient formation−diffusion−hydrogenation chain of H* by diminishing H* adsorption. Spectroscopic characterizations indicate that Cu/ceria interfacial perimeter enriches the local furfural, synergistically lowering the barrier of the rate-determining HAT step across the perimeter. Our Cu/ceria catalyst realizes high-rate HAT-dominated ECR for electrosynthesis of single-product furfuryl alcohol, achieving a high production rate of 19.1 ± 0.4 mol h
−1
m
−2
and a Faradaic efficiency of 97 ± 1% at an economically viable partial current density of over 0.1 A cm
−2
. Our results demonstrate a highly efficient route for biofeedstock valorization with enhanced techno-economic feasibility.
KLF2 expression in IgG plasma cells at their induction site regulates the migration program
Authors: Ise Wataru , Koike Takuya , Shimada Nozomi , Yamamoto Hiromi , Tai Yuki , Shirai Taiichiro , Kawakami Ryoji , Kuwabara Mana , Kawai Chie , Shida Kyoko , Inoue Takeshi , Hojo Nozomi , Ichiyama Kenji , Sakaguchi Shimon , Shiroguchi Katsuyuki , Suzuki Kazuhiro , Kurosaki Tomohiro
Published: February 2025

Newly generated plasma cells in secondary lymphoid organs migrate to niches in the bone marrow, wherein they survive as long-lived plasma cells (LLPCs). Although LLPCs have been extensively characterized, it is still unclear what the key determinant(s) are for plasma cell longevity. One model postulates that plasma cell heterogeneity is established at the induction site, thereby instructing their longevity. Here, we found that, among newly generated IgG plasma cells, integrin β7hi marks plasma cells predisposed to home to the bone marrow, whereas integrin β7lo cells remain in secondary lymphoid organs. Mechanistically, this egress-prone fraction had a higher expression of the KLF2 transcription factor, the loss of which resulted in defective egress by downregulating S1PR1 and CD11b. Disruption of plasma cell egress results in defective antibody durability, thereby making mice more susceptible to influenza reinfection. Thus, the migration program of plasma cells established at the induction site plays a critical role in determining antibody durability.
A “second hit” impacts disease severity in a dominantly inherited genetic skin disorder
Authors: Coulombe Pierre A.
Published: February 2025

In this issue of JEM, Bergson et al. (https://doi.org/10.1084/jem.20240827) identified variants in HMCN1 that co-segregate with and account for variations in disease severity in individuals with a diagnosis of epidermolysis bullosa simplex (EBS) resulting from pathogenic variants in KRT14. The authors show that hemicentin-1 binds keratin 14 at the protein level and that silencing HMCN1 expression disrupts the organization of K14-containing filaments in epidermal keratinocytes and their attachment to the extracellular matrix. These findings address the clinical heterogeneity observed in EBS, a rare genetic skin disorder, with general implications for all genodermatoses.
Fighting Newtonian noise with gradient-based optimization at the Einstein Telescope
Authors: Schillings Patrick , Erdmann Johannes
Published: February 2025

Newtonian noise in gravitational wave detectors originates from density fluctuations in the vicinity of the interferometer mirrors.At the Einstein Telescope, this noise source is expected to be dominant for low frequencies. Its impact is proposed to be reduced with the help of an array of seismometers that will be placed around the interferometer endpoints.We reformulate and implement the problem of finding the optimal seismometer positions in a differentiable way. We then explore the use of first-order gradient-based optimization for the design of the seismometer array for 1 Hz and 10 Hz and compare its performance and computational cost to two metaheuristic algorithms. For 1 Hz, we introduce a constraint term to prevent unphysical optimization results in the gradient-based method.In general, we find that it is an efficient strategy to initialize the gradient-based optimizer with a fast metaheuristic algorithm. For a small number of seismometers, this strategy results in approximately the same noise reduction as with the metaheuristics. For larger numbers of seismometers, gradient-based optimization outperforms the two metaheuristics by a factor of 2.25 for the faster of the two and a factor of 1.4 for the other one, which is significantly outperformed by gradient-based optimization in terms of computational efficiency.
The twisting index in semitoric systems
Authors: Alonso Jaume , Hohloch Sonja , Palmer Joseph
Published: February 2025

Semitoric integrable systems were symplectically classified by Pelayo and Vũ Ngọc in 2009–2011 in terms of five invariants. Four of these invariants were already well-understood prior to the classification, but the fifth invariant, the so-called twisting index invariant, came as a surprise. Intuitively, the twisting index encodes how the structure in a neighborhood of a focus–focus fiber compares to the large-scale structure of the semitoric system and it was originally defined by comparing certain momentum maps. In the first half of the present paper, we produce several new formulations of the twisting index which give rise to dynamical, geometric, and topological interpretations. More specifically, we describe it in terms of differences of action variables, Taylor series, and homology cycles. In the second half of the paper, we compute the twisting index invariant of a specific family of systems with two focus–focus singular points (the so-called generalized coupled angular momenta), which is the first time that the twisting index has been computed for a system with more than one focus–focus point. Moreover, we also compute the terms of the Taylor series invariant up to second order. Since the other invariants of this family were already computed, this becomes the third family of semitoric systems for which all invariants are known, after the coupled spin oscillators and the coupled angular momenta.
Validation of patient-specific deep learning markerless lung tumor tracking aided by 4DCBCT
Authors: Huang Lili , Thummerer Adrian , Papadopoulou Christianna Iris , Corradini Stefanie , Belka Claus , Riboldi Marco , Kurz Christopher , Landry Guillaume
Published: February 2025

Abstract. Objective. Tracking tumors with multi-leaf collimators and X-ray imaging can be a cost-effective motion management method to reduce internal target volume margins for lung cancer patients, sparing normal tissues while ensuring target coverage. To realize that, accurate tumor localization on X-ray images is essential. We aimed to develop a systematic method for automatically generating tumor segmentation ground truth (GT) on CBCT projections and use it to help refine and validate our patient-specific AI-based tumor localization model. Approach. To obtain the tumor segmentation GT on CBCT projections, we propose a 4DCBCT-aided GT generation pipeline consisting of three steps: breathing phase extraction and 10-phase 4DCBCT reconstruction, manual segmentation on phase 50%, deformable contour propagation to other phases, and forward projection of the 3D segmentation to the CBCT projection of the corresponding phase. We then used the CBCT projections from one fraction in the angular range of [−10°, 10°] and [80°, 100°] to refine a Retina U-Net baseline model, which was pretrained on 1140231 digitally reconstructed radiographs generated from a public lung dataset for automatic tumor delineation on projections, and used later-fraction CBCT projections in the same angular range for testing. Six LMU University Hospital patient CBCT projection sets were reserved for validation and 11 for testing. Tracking accuracy was evaluated as the center-of-mass (COM) error and the Dice similarity coefficient (DSC) between the predicted and ground-truth segmentations. Main results. Over the 11 testing patients, each with around 40 CBCT projections tested, the patient-refined models had a mean COM error of 2.3±0.9mm / 4.2±1.7mm and a mean DSC of 0.83±0.06 / 0.72±0.13 for angles within [−10°, 10°] / [80°, 100°]. The mean inference time was 68 ms/frame. The patient-specific training segmentation loss was found to be correlated to the segmentation performance at [−10°, 10°]. Significance. Our proposed approach allows patient-specific real-time markerless lung tumor tracking, which could be validated thanks to the novel 4DCBCT-aided GT generation approach.
Four Total Eclipsing Contact Binary Systems: The First Photometric Light Curve Solutions Employing TESS and Gaia Surveys
Authors: Poro Atila , Aliakbari Razieh , Azarara Hossein , Ababafi Asma , Nasirian Sadegh
Published: February 2025

We presented the first photometric light curve solutions of four W Ursae Majoris (W UMa)-type contact binary systems. This investigation utilized photometric data from the Transiting Exoplanet Survey Satellite (TESS) and Gaia Data Release 3 (DR3). We used the PHysics Of Eclipsing BinariEs (PHOEBE) Python code and the Markov Chain Monte Carlo (MCMC) method for these light curve solutions. Only TIC 249064185 among the target systems needed a cold starspot to be included in the analysis. Based on the estimated mass ratios for these total eclipse systems, three of them are categorized as low mass ratio contact binary stars. The absolute parameters of the systems were estimated using the Gaia DR3 parallax method and the orbital period and semi-major axis ($P-a$) empirical relationship. We defined that TIC 318015356 and TIC 55522736 systems are A-subtypes, while TIC 249064185 and TIC 397984843 are W-subtypes, depending on each component's effective temperature and mass. We estimated the initial masses of the stars, the mass lost by the binary system, and the systems' ages. We displayed star positions in the mass-radius, mass-luminosity, and total mass-orbital angular momentum diagrams. In addition, our findings indicate a good agreement with the mass-temperature empirical parameter relationship for the primary stars.
Precision non-invasive brain stimulation: an in silico pipeline for personalized control of brain dynamics
Authors: Karimi Fariba , Steiner Melanie , Newton Taylor , Lloyd Bryn Alexander A. , Cassarà Antonino M , de Fontenay Paul , Farcito Silvia , Triebkorn Jan Paul , Beanato Elena , Wang Huifang , Iavarone Elisabetta , Hummel Friedhelm C , Kuster Niels , Jirsa Viktor , Neufeld Esra
Published: February 2025

Objective: Non-invasive brain stimulation (NIBS) offers therapeutic benefits for various brain disorders. Personalization may enhance these benefits by optimizing stimulation parameters for individual subjects. Approach: We present a computational pipeline for simulating and assessing the effects of NIBS using personalized, large-scale brain network activity models. Using structural MRI and diffusion-weighted imaging data, the pipeline leverages a convolutional neural network-based segmentation algorithm to generate subject-specific head models with up to 40 tissue types and personalized dielectric properties. We integrate electromagnetic simulations of NIBS exposure with whole-brain network models to predict NIBS-dependent perturbations in brain dynamics, simulate the resulting EEG traces, and quantify metrics of brain dynamics. Main results: The pipeline is implemented on o2S2PARC, an open, cloud-based infrastructure designed for collaborative and reproducible computational life science. Furthermore, a dedicated planning tool provides guidance for optimizing electrode placements for transcranial temporal interference stimulation. In two proof-of-concept applications, we demonstrate that: (i) transcranial alternating current stimulation produces expected shifts in the EEG spectral response, and (ii) simulated baseline network activity exhibits physiologically plausible fluctuations in inter-hemispheric synchronization. Significance: This pipeline facilitates a shift from exposure-based to response-driven optimization of NIBS, supporting new stimulation paradigms that steer brain dynamics towards desired activity patterns in a controlled manner.
A comparative EEG analysis of classifying short sleep phases and waking states using support vector machine and random forest
Authors: Xuan Nhi Yen Phan , Pham Bao Minh , Quoc Khai Le
Published: February 2025

Multiple studies suggest that the various stages of sleep affect the effectiveness of taking a nap. For this reason, the purpose of this study is to develop a model that may be used to classify the first and second stages of short sleep or the awake state. We employ sleep recordings obtained from the open-access dataset. To enhance the quality of recorded EEG signals, we implement a Notch Filter to reduce power line noise and a 0.5–70 Hz bandpass (Butterworth) filter to isolate the pertinent EEG signals. Two classifiers, Support Vector Machine (SVM) and Random Forest (RF), are used to assess and compare the performance of classification. In addition, the mRmR (minimal Redundancy Maximum Relevance) feature selection approach is employed to improve the model efficiency. The outcomes of our study reveal that both classifiers for each subject have an accuracy rate approaching 80%, differentiating between wakefulness and phases 1 and 2 of short sleep. This study emphasizes the efficacy of these strategies in offering essential instruments for comprehending and enhancing nap efficiency.
Study on lightweight optimization of battery pack box structure for electric vehicle
Authors: Jing Min , Chang Huirong , Lv Jiangyi , Li Gang , Zhu Qingsong
Published: February 2025

A lightweight optimization design process for the battery pack box body of the electric vehicle is proposed based on the lightweight and performance indicators of the battery pack box body. The compression, mode, and strength working conditions of the original design battery pack are analyzed using HyperWorks software. According to the lightweight optimization design process of the battery pack box body, topology optimization and morphology optimization methods are used to improve the performance and lightweight optimization of the typical extruded aluminum profiles and plates of the original design battery pack box body. After optimization, a weight reduction of 2.76 kg is achieved. At the same time, the strength, mode, stiffness and other performance of the battery pack box body meet the requirements of the indicators. The lightweight solution for the battery cover has been put into mass production application.
Fine-grained TWIP steel prepared by powder metallurgy
Authors: Huang Liangliang , Liu Xu , Wang Dan
Published: February 2025

Five fine-grained TWIP steels are produced by powder metallurgy. With increasing milling time of the mixed powder, the grain size of the sintered bulk samples decreases from 11.9 μm to 2.9 μm. The grain size refinement can be primarily attributed to a reduction in particle size, a higher degree of alloying and dislocation accumulation in the blend powder. All bulk samples consist of equiaxed grains with many annealing twins, a few stacking faults and nanoscale dispersed particles. With decreasing grain size, the compressive yield strength of the bulk sample increases to 411 MPa, while the yield stress increases significantly but the plasticity gradually declines. As with conventionally cast TWIP steels, the mechanical properties show a typical grain size dependence.
Multi-objective robust design of the front structure of white body
Authors: Liu Zhuchun , Liu Zhen , Feng Haisheng
Published: February 2025

The software platform developed was applied to the multi-objective robust design of the pure electric vehicle body structure, which was obtained through topology optimization under multiple working conditions. Based on the response observation values obtained from the simulation analysis, a multi-objective robust design is carried out to obtain the optimal combination of optimized structural dimensions, completing the multi-objective robust design of the body structure. Through the application of the developed multi-objective robust parametric optimization software, the safety of the body structure and the efficiency of structural optimization are effectively improved.
Study on fracture/deformation failure behavior of a TC4 titanium alloy coupling bolt
Authors: Sui Jiuling , Yang Yun , Wang Hongli
Published: February 2025

A pressure vessel used 24 TC4 titanium alloy M16×70 bolts to connect the combustion chamber and the rear head. While, the bolts fractured/deformed during the pressure test. The mechanism was confirmed through several methods including calculation, simulation, and test. Then, the problem was completely solved by conducting comprehensive optimization measures including replacing the bolt’s material, increasing the bolt’s quantities and specifications, and improving the connection structure.
Research on effect of pre-stress on cutting force of metal bar surface notching in low-stress cropping
Authors: Xu Jiayi , Zhang Lijun , Zhao Qing , Sun Dejingwei , Wang Chen , Yang Jianming
Published: February 2025

Under the low-stress cropping working condition, a pre-stress notching technology is proposed. According to the force and deformation features of the bar, a cutting force model of notching is established to divide the cutting area into three parts and analyze the mechanism of splitting and friction respectively. The pre-stress notching experiment platform is built to conduct the comparison test between the cutting force of notching under the pre-stressed state and the free state. The experimental results show that the reasonable pre-stress state reduces the shear part and the friction part by 25.4% and 47.8% respectively, which can effectively improve the cropping efficiency and prolong the durability of the cutting tool.
Strength test analysis of intercity locomotive frame
Authors: Li Yuhan , Zheng Tianrui , Xu Ling
Published: February 2025

The intercity locomotive bogie is a crucial transportation infrastructure component, with the frame serving as a vital load-bearing element. Its mechanical properties significantly influence the support of the car body and ensure the stable operation of locomotive vehicles. To enhance the fatigue reliability of the bogie frame and provide relevant data, this study focuses on analyzing the frame’s strength in both the design and manufacturing stages, based on the bogie of a specific intercity locomotive. The investigation follows the EN13749 and UIC615-4 standards to assess the static and fatigue strength of the frame. First, the static strength of the frame was tested under the corresponding loads. Next, the fatigue strength was evaluated after subjecting the frame to several fatigue cycles. The test results indicated that the frame’s static strength met the specified requirements. Fatigue strength was assessed by using a simulated operating environment, with stress amplitudes at each measurement point falling within the material’s fatigue limit, as outlined by the Goodman diagram. Following 10 million load cycles, no cracks were detected during non-destructive testing, confirming that the frame passed the fatigue test.
Numerical simulation and analytical coupling study on cavity expansion of solid materials
Authors: Wu Guoliang , Wang Hua
Published: February 2025

This study employed the Plastic-Kinematic constitutive model to conduct three-dimensional numerical simulations on armor alloys and aluminum alloys, aiming to explore their impact resistance during spherical and cylindrical cavity expansion. Through the coupling of simulation data and analytical formulas, we derived a calculation formula for expansion velocity, considering both cavity wall stress and radial pressure in static cavity expansion. The radial pressure in static cavity expansion was accurately determined through numerical simulations, and its relationship with yield strength was thoroughly analyzed. Additionally, we verified the accuracy of the mechanical parameters Asce and B for spherical cavity expansion velocity. Normalization of the expansion velocity formulas for spherical and cylindrical cavities simplified the description of expansion velocity for different cavity shapes. The feasibility and universality of the proposed normalization analytical formula were validated through comparisons with literature data. This formula, applicable to metal materials within a specific yield strength range, accurately describes the expansion pressure and velocity characteristics during cavity expansion, providing a rapid and effective solution for research on projectile penetration into solid materials and valuable references for further exploration in related fields.
Calibration method for high-frequency electrotome quality analyzer based on a specific device
Authors: Xu Yang , Fu Yanxiang , Liu Wei , Xie Chuandong , Ren Tingting
Published: February 2025

High frequency electrotome quality analyzer is widely used by medical institutions, medical equipment manufacturers, and medical equipment testing institutions. There are several important technical indicators, such as high-frequency power, high-frequency leakage current, and output resistance, to evaluate the metrological performance of high-frequency electrotome quality analyzers, but currently, there are no corresponding verification regulations or calibration specifications. This article presents a calibration method for high frequency electrotome quality analyzers by selecting a specific test device, and the rationality of the method is evaluated by verification experiments, which are conducted on typical types of quality analyzers manufactured by mainstream manufacturers. The experimental results are compared with the requirements stipulated by the national calibration specification JJF 1217-2009 Calibration Specification for Electrosurgical Generator to determine the feasibility of the presented calibration method.
Research on quantitative characterization method of tensile and compressive stress based on incremental magnetic permeability principle
Authors: Li Hengtao , Liu Yan , Yao Huan , Wang Xianxian
Published: February 2025

In this study, non-destructive quantitative characterization of stresses in low, medium, and high carbon steels was carried out based on the principle of incremental permeability (IP) detection. First, a special fixture was designed and constructed to perform calibration experiments on a single flat plate tensile specimen to obtain the incremental magnetic permeability signals at different compressive and tensile stress levels. Subsequently, the relationship between the magnetic parameter and the stress characterization was analyzed. Finally, a network model was established to realize the quantitative characterization of tensile and compressive stresses in low, medium, and high carbon steels using the magnetic parameter. The results show that the incremental magnetic permeability detection technique can effectively predict the carbon steel stresses non-destructively and quantitatively, and the average relative errors of the model predicted low, medium, and high carbon steel stresses are 1.60 MPa, 1.28 MPa, and 2.54 MPa, respectively. The methods and conclusions proposed in this study provide important references for non-destructive testing of carbon steel stresses.
Preparation of large-scale high-performance precipitation-hardening high-entropy alloys by rotary forging
Authors: Xiao Yao , Wang Lu , Xue Yunfei
Published: February 2025

The size of the Al0.5Cr0.9FeNi2.5V0.2 specimen, which is a high-performance coherent precipitation-hardening high-entropy alloy, is constrained by the deformation homogeneity required in its thermomechanical processing. In previously published works, cold rolling could only achieve small-sized thin sheet samples with a thickness of less than 4 mm, limiting its engineering applications. This study utilized the strain gradient generated by rotary forging, matching the mechanical characteristics of the hardcore and ductile surface of large-sized high-entropy alloy rods, achieving a diameter of up to 13.5 mm. The alloy exhibited consistent microstructure and mechanical properties comparable to small-sized samples. This work enhances the potential for manufacturing medium and small-sized high-performance HEA components, such as piston rods and armor-piercing projectiles.
Optical and mechanical properties of Gd2O3-MgO nanocomposites sintered by hot-isostatic-pressing using the nanopowders via glycine combustion method
Authors: Tang Hengwei , Wu Nan , Hu Kai , Shao Cen , Hou Zhaoxia
Published: February 2025

The glycine combustion method combined with hot-isostatic-pressing sintering technology is an effective approach to fabricating nanocomposites. We reported that the Gd2O3-MgO nanocomposites had excellent optical and mechanical performances. The nanopowders with low agglomeration were obtained by elaborating the mole ratio of metal cation to glycine. The excellent optical transmittance (78.2%~80.8%) over 3-6 μm and the high values for Vickers hardness (9.6±0.3 GPa) and bending strength (192.7±8.1 MPa) were obtained by hot-isostatic-pressing sintering at 1350°C with 200 MPa pressure.
The optimization of drill rig structure based on the solid isotropic material with penalization
Authors: Zhang Hong , Su Yongjian , Wang Lun , Zhu Yuxiang , Hu Guowei , Lu Chaoxin , Tang Longjiang , Zhao Shanfei
Published: February 2025

This paper presents the optimization design of a drill rig structure based on the Solid Isotropic Material with Penalization, aimed at enhancing its adaptability in engineering applications by reducing weight and improving mechanical performance. A 3D model and finite element analysis were first established to simulate and verify the mechanical properties of the drill rig structure, revealing potential for optimization. The Solid Isotropic Material with Penalization was then employed to optimize design variables and objective functions. As a result, the drill rig’s weight was reduced from 76.2 kg to 45.8 kg, with maximum deformation decreasing by approximately 30.7% and maximum stress lowering by about 15.3%. This study demonstrates the effectiveness of the Solid Isotropic Material with Penalization in optimizing complex structures, achieving both weight reduction and enhanced mechanical performance, and providing theoretical support for practical engineering applications.