bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of strain gradient and interface engineering on the high-temperature energy storage capacitors
Authors: Hu Guangliang , Lu Rui , Hu Tian-Yi , Ma Chunrui , Liu Ming
Published: September 2024

The miniaturization and high integration of electronic devices pose new requirements for the energy storage density and high-temperature performance of dielectric capacitors. For thin film materials, internal stress and the interface layer often show a significant impact on their energy storage performance. Therefore, the capacitors with different stress gradient sequences and different periods were designed by BaHf0.17Ti0.83O3 (BHTO17), BaHf0.25Ti0.75O3 (BHTO25), and BaHf0.32Ti0.68O3 (BHTO32) to investigate the effect of stress gradient and interface engineering on the energy storage characteristics. Dielectric thin film structures with upward gradient, downward gradient, and periodic upward gradient (4N) were constructed. The study found that the upward gradient structure had higher breakdown field strength than the downward gradient structure. This is because the upward gradient structure can effectively extend the ending electric field of the Ohmic conduction mechanism and delay the activation electric field of the F–N tunneling mechanism. The 4N structure had a slightly higher breakdown field strength (reaching 9.22 MV/cm) compared to the pure upward gradient structure. The 4N structure thin film also exhibited higher energy storage density (115.44 J/cm3) and wide temperature (−100 to 400 °C) characteristics. These findings provide important guidance and application value for improving the energy storage characteristics of dielectric capacitors at high temperatures through structural design.
Investigation of the pulse characteristics of an injection seeded diamond Raman amplifier
Authors: Zheng Hao , Bai Zhenxu , Hao Xin , Ding Jie , Qi Yaoyao , Yan Bingzheng , Wang Yulei , Lu Zhiwei
Published: September 2024

Raman amplification is a highly efficient means by which amplification of laser radiation and beam clean-up can be achieved. Although this process has been described in the literature, little attention has been given to the investigation of pulse characteristics of the laser fields involved in the process. In this work, we analyze the evolution of the fundamental and Stokes fields involved in the Raman amplification process, with a focus on Stokes extraction efficiency within a diamond Raman amplifier. This work offers insight into the means by which the Raman amplification process can be optimized/maximized for a given set of laser fields. Experimental observations show that depletion of the fundamental field occurs during the amplification process, causing an initially Gaussian pulse shape to become increasingly concave. The rate at which the pulse peak diminishes and the overall shape becomes concave is correlated with the rate of amplification of the Stokes field pulse intensity. This experimental observation is supported by theoretical modeling using rate equations wherein Raman amplification under different initial conditions is numerically simulated, and the energy extraction efficiency and pulse shapes under different intensities are analyzed. Experimentally, the amplified laser output of the Stokes field from this system is 4.2 mJ (equivalent to a peak power of up to 37.5 kW), and an amplification efficiency of 18% is achieved.
Chief executive officers retention model for Australian hospitals
Authors: Mathew Nebu , Liu Chaojie (George) , Khalil Hanan
Published: September 2024

Objective This study aims to develop a comprehensive chief executive officer (CEO) retention model for Australian hospitals, addressing high turnover rates by integrating key retention strategies to promote organisational stability and enhance patient care. Methods The study employed a sequential exploratory design with four stages: a scoping review, qualitative interviews, a quantitative survey, and comprehensive data analysis. The scoping review examined existing literature on CEO turnover and retention. Qualitative interviews with 14 Australian hospital CEOs provided in-depth insights. A quantitative survey with 51 CEOs validated the findings. Data triangulation ensured a robust and contextually relevant model aligned with Transformational Leadership Theory and a systems approach. Results Five key factors influencing CEO retention were identified: mutual respect and clear roles between CEOs and boards, fostering a positive organisational culture, competitive rewards, robust recruitment and retention practices, and ongoing professional development and mentorship. The model emphasises a supportive environment, equitable compensation, effective succession planning, and leadership development. Findings indicate a holistic approach addressing both professional environment and personal growth is essential for improving CEO retention rates. Conclusions The CEO retention model provides practical solutions to reduce turnover and enhance stability in Australian hospitals. By incorporating Transformational Leadership Theory and a systems approach, the model offers a comprehensive framework that addresses the multifaceted nature of CEO retention. Future research should refine these strategies and explore their applicability in different healthcare settings to further enhance effectiveness.
Community-level effects of ivermectin and moxidectin from cattle dung: zooplankton as study case
Authors: Lorente Camila J. , Flores-Mendez Daniel N. , Mesa Leticia M. , Miró M. Victoria , Lifschitz Adrián , Gutierrez M. Florencia
Published: September 2024

Context Ivermectin (IVM) and moxidectin (MOX), are widely used internal and external antiparasitic drugs for livestock. They enter into the aquatic environment because the treated animals metabolise only a small percentage of the administered doses, and the rest is eliminated through the faeces posing a risk to aquatic organisms. Aims This study aimed to evaluate the responses of zooplankton to environmentally relevant concentrations of IVM and MOX spiked in cattle dung in a short-term exposure. Methods We compared the composition of the community, density, species richness, diversity and total biomass between treatments with parasiticides and controls. Key results The presence of both antiparasitic drugs altered the zooplankton community structure, leading to a shift in species composition. Cladocerans were the most affected, with a drastic reduction in their density. Additionally, a decrease in the density of copepods and an increase in the density of rotifers were observed in the MOX treatments. Conclusions Both drugs caused a simplification of the zooplankton community as species richness and diversity decreased. Overall, MOX was more toxic than IVM. Implications Our results suggest that long-term consequences on ecosystem services could arise, which merits the development of control and livestock management tools for the protection of these environments.
Ambiguity in discourse
Authors: Achimova Asya , Ebert-Rohleder Maren , Geiger Lorenz , Klenk Joel , Reid Michael , Vollstedt Thalia , Zirker Angelika
Published: September 2024

Ambiguity in language and communication has recently come
under increasing attention in a number of disciplines, such as
linguistics, literary science, psychology, theology, and law. In
this paper, we focus on ambiguity in discourse and present an online
corpus which contains rich annotations for a variety of examples of
ambiguity from different text genres and periods. The corpus
features an annotation schema that allows users to specify the
multiple attributes of an ambiguity, as well as its interaction with
related but distinct phenomena, such as vagueness and
underspecification. We discuss how this corpus might foster and
enable the interdisciplinary study of ambiguity.
Towards a practice of translanguaging subtitling for the mediatised articulation
of fangyan
Authors: Wang Dingkun , Zhang Xiaochun
Published: September 2024

This article addresses an underexplored intersection between subtitling and translanguaging with reference to the
representation of diverse Chinese fangyan in hip-hop music videos. Drawing on recent progress in the intersection
between translanguaging and Translation Studies, the article sketches the multilingualism of the Han ethnic majority and its
precarious existence under the governmental policy and language planning of China. Second, it contextualises the rising audibility
and visibility of local speeches and non-standard writing in cinematic, metrolingual, and digital cultures. This highlights the
social and technological conditions that enable culture creators and language users to practice novel representations of
linguistic diversity and variations in the subtitling medium. Furthermore, the case-study analyses illustrate how Chinese hip-hop
musicians assemble linguistic, multimodal, and multisemiotic resources to effect translanguaging performance across different
communicational repertoires. The conclusion outlines the practical and theoretical implications of translanguaging subtitles for
alternative media representations of linguacultural diversities in China and beyond.
Dispersive Analysis of Excited Glueball States
Authors: Li Hsiang-nan
Published: September 2024

Motivated by the determination for the spin-parity quantum numbers of the X(2370) meson at BESIII, we extend our dispersive analysis on hadronic ground states to excited states. The idea is to start with the dispersion relation which a correlation function obeys, and subtract the known ground-state contribution from the involved spectral density. Solving the resultant dispersion relation as an inverse problem with available operator-product-expansion inputs, we extract excited-state masses from the subtracted spectral density. This formalism is verified by means of the application to the series of ρ resonances, which establishes the ρ(770), ρ(1450) and ρ(1700) mesons one by one under the sequential subtraction procedure. Our previous study has suggested the admixture of the f
0(1370), f
0(1500) and f
0(1710) mesons (the η(1760) meson) to be the lightest scalar (pseudoscalar) glueball. The present work predicts that the f
0(2200) (X(2370)) meson is the first excited scalar (pseudoscalar) glueball.
Comment on ‘Resonant inelastic x-ray scattering from U3O8 and UN’
Authors: Miskowiec Andrew , Spano Tyler , Brubaker Z E , Niedziela J L , Abernathy D L , Hunt Rodney D , Finkeldei S
Published: September 2024

In a recent manuscript, Lawrence Bright et al (2023 J. Phys.: Condens. Matter
35 175501) reported the resonant inelastic x-ray scattering spectra of U3O8, as well as UN. Their goal was to identify electronic multiplets associated with a 5f
1 configuration with ground state

2

F

5
/
2

. Complete active space self-consistent field with spin–orbit coupling (CASSCF-SOC) predicted that

2

F

5
/
2

transitions should be observable at 190 and 328 meV. However, these energies were not accessible in their experiment. They suggested that the recent inelastic neutron scattering results of Miskowiec et al (2021 Phys. Rev. B 103 205101) could have been sensitive to these transitions. Here we show that transitions of this possible origin appear in that dataset near 198, 262, 362, and potentially 448 meV.
Transport of a comb-like polymer across a nanochannel subject to a pulling force
Authors: Adane Meseret , Tatek Yergou B , Tilahun Mesay
Published: September 2024

We investigate the dynamics of comb-like polymer translocation through a nanochannel using three-dimensional Langevin dynamics simulations based on a coarse-grained chain model. A comprehensive set of simulations are performed to examine the effects of system parameters such as the grafting density ρ of the side chains, the polymer chain length, the nanochannel dimensions, and the magnitude of the pulling force on the translocation dynamics. For a given polymer chain length, keeping the backbone length is constant while varying ρ, we have found that the dependence of the mean translocation time

⟨
τ
⟩

on ρ is non-monotonic, with a maximum translocation time for a specific ρ at which the translocation is the slowest. The simulation results also show that

⟨
τ
⟩

is not significantly affected by the channel width above a certain radius, while the comb-like polymer translocation is hindered by a narrower channel due to increased interactions between the chain monomers and the channel. In addition,

⟨
τ
⟩

increases linearly with the nanochannel length. A linear scaling relationship between the mean translocation time

⟨
τ
⟩

and the chain length N of polymer is obtained,

⟨
τ
⟩

∼
N

. Similarly, the dependence of

⟨
τ
⟩

on the backbone chain size

N

bb

has a quasi-linear dependence,

⟨
τ
⟩

∼

N

bb

. On the other hand, the translocation velocity v follows a power-law relationship with the polymer chain length N as

v
∼

N

−
1

. The mean translocation time also shows an inverse linear relationship with the magnitude of the pulling force F,

⟨
τ
⟩

∼

F

−
1

. The power-law relationships discovered in this study contribute to the fundamental understanding of the comb polymer translocation dynamics and to establishing a framework for further investigations in this field.
Robust and efficient calibration method of liquid-crystal spatial light modulator based on the linear combination strategy
Authors: Li Junxiang , Fan Chen , Du Yijun , Hu Zirui , Shu Long , Chen Huan , Zhao Hong , Zhao Zixin
Published: September 2024

Phase-only spatial light modulators (SLMs) play a vital role in virous fields. However, its modulation accuracy is compromised by the static aberration and the phase response nonlinearity. To enhance the modulation accuracy, this paper presents an innovative full calibration method for SLMs, effectively addressing both static aberration and nonlinear phase responses using only two shots of the camera. The main highlight of this paper is the binding of a novel linear combination strategy and a unique kinoform. This binding can eliminate phase distortion between two shots of the camera, making our method dramatically robust in correcting phase response nonlinearity. Additionally, benefiting from the accurate correction of phase response nonlinearity, the static aberration is accurately compensated by the single-shot spatial carrier phase-shifting technology. In conclusion, the proposed method’s strong robustness, precision, and efficiency position it as an ideal solution for SLM calibration.
A numerical analysis of the short open load calibration robustness for capacitance measurements in scanning microwave microscopy
Authors: Richert Damien , Deleruyelle Damien , Morán-Meza José A , Kaja Khaled , Imanaliev Almazbek , Hoffmann Johannes , Gautier Brice , Piquemal François
Published: September 2024

Numerous experimental parameters affect the accuracy of impedance measurements in scanning microwave microscopy (SMM). Investigating their effects on the measured values is particularly challenging. Here, we present the development of a fully-numerical finite element method-based simulation of the actual SMM measurements. We demonstrate the application of a self-calibration procedure for the simulated SMM measurements with a maximal deviation of ±0.8% relative to reference capacitances determined via an electrostatic finite element model. Furthermore, we demonstrate the possibility of assessing water meniscus-induced effects on the simulated SMM measurements. Typically, water meniscus impacts the calibration by a 0.4% relative deviation, in accordance with previously reported empiric data. Our findings are expected to promote access to a deeper understanding of nanoscale capacitance measurements in SMM.
A new combined transient electromagnetic noise reduction method of VMD-SVD-WTD based on improved dung beetle optimization algorithm with multi-strategy fusion
Authors: Song Duxi , Feng Guorui , Qi Tingye , Wang Haochen , Pan Dawei , Zhang Lifeng
Published: September 2024

The transient electromagnetic method (TEM) is now commonly used in the detection of coal mined-out areas, but it is susceptible to various sources of noise during field site probing, significantly impacting the accuracy of detection. Variational mode decomposition (VMD) has gained widespread adoption for eliminating noise in TEM signals. However, a single VMD may not effectively address both full-band noise and residual Gaussian white noise. To address this limitation, the singular value decomposition (SVD) and wavelet threshold denoising (WTD) are introduced correspondingly. Furthermore, this paper tackles challenges related to parameters selection in VMD and traditional optimization algorithms by proposing the integration of dung beetle optimization (DBO) enhanced with circle chaotic mapping, random walk strategy, and crisscross optimization algorithm (CRCDBO). Consequently, a new combined TEM noise reduction method, VMD-SVD-WTD based on CRCDBO is presented. Through comprehensive simulation tests and comparative analyses, the signal-to-noise ratio of this method is improved by 12.79% compared with VMD and the RMSE is 0.0011, which demonstrate the superiority and effectiveness of VMD-SVD-WTD based on CRCDBO in noise reduction. Meanwhile, this method is applied to an iron ore mine in Shanxi, which can accurately monitor the location of the mined-out area and has good application value.
Improving the coverage area and flake size of ReS2 through machine learning in APCVD
Authors: Flores Salazar Mario , Frausto-Avila Christian Mateo , de Jesús Bautista Javier A , Polumati Gowtham , Muñiz Martínez Barbara A , Sekhar Reddy K Chandra , Hernández-Vázquez Miguel Ángel , Strupiechonski Elodie , Sahatiya Parikshit , Quiroz-Juárez Mario Alan , De Luna Bugallo Andres
Published: September 2024

Machine learning is playing a crucial role in optimizing material synthesis, particularly in scenarios where several parameters related to growth exhibit different and significant outcomes. An example of such complexity is the growth of atomically thin semiconductors through chemical vapor deposition (CVD), where multiple parameters can influence the thermodynamics and reaction kinetics involved in the synthesis. Herein, we performed a set of orthogonal experiments, varying the key parameters such as temperature, carries gas flux and precursor position to identify the optimal conditions for maximizing covered area and the size of rhenium disulfide (ReS2) crystals. The experimental results were used to establish correlations among the three thermodynamic variables through an artificial neural network. Contour plots were then generated to visualize the impact on the coverage and flake size of the crystals. This study demonstrates the capability of machine learning to enhance the potential of CVD-growth for the integration of 2D semiconductors like ReS2 at larger scales.
The propagation of negative pulsed discharges facilitated by artificially injected gas bubble in water
Authors: Pan Teng , Lv Jiahao , Sun Ying , Zhang Yuantao , Timoshkin Igor
Published: September 2024

The artificial injection of bubbles into the electrode gap can effectively enhance the performance of underwater pulsed spark discharge (UPSD). It is crucial to investigate the morphology and propagation characteristics of discharges for a comprehensive understanding of bubble-stimulated UPSD. This paper presented an extensive study of negative discharges facilitated by the injected large bubble (with a diameter of 3 mm) in UPSD. The bridging effect of the bubble and the morphology and propagation of discharges were observed through the shadowgraph images captured by a high-speed camera. A numerical model was built to analyse the influence of the bubble on the initial electric field distribution between the electrodes. The characteristics of discharges were notably influenced by bubble parameters and energization conditions. Not in all cases could the bubble play the bridging effect role. The effective range of the bubble was roughly confined to a small region near the HV electrode tip. The experimental results obtained in this paper have certain guiding significance for the practical application of UPSD.
WSe2/n-GaN and WSe2/p-GaN heterojunction band alignment
Authors: Wei Wanting , Zhao Guijuan , Liu Xiacong , Lv Xiurui , Wang Xingliang , Liu Guipeng
Published: September 2024

In this work, we measured the band alignment of 2D/3D heterostructures of WSe2 on n-doped, p-doped, and intrinsic GaN by x-ray photoelectron spectroscopy. The WSe2/n-GaN heterojunction exhibits type-II band alignment, with measured valence band offset (VBO) and conduction band offset (CBO) values of 2.28 ± 0.15 eV and 0.96 ± 0.15 eV, respectively. On the other hand, the WSe2/p-GaN heterojunction shows type-I band alignment, with measured VBO and CBO values of 0.1 ± 0.15 eV and 1.22 ± 0.15 eV, respectively. The results show that doping has a significant effect on the arrangement of the energy bands of the heterostructure, and provides a reference for device applications based on heterojunctions.
Optimized design and performance study of internal nested structure based on Fin Ray structure
Authors: Kang Yuzhe , Zhou Maoying , Wang Ban , Liu Rong , Qin Huawei
Published: September 2024

As a famous type of passive soft gripper, fin ray gripper is easily adaptable to object shapes and compatible with various actuation mechanisms. Also, it has been shown that internally embedded substructures can significantly affect the adaptability and gripping performance of fin ray grippers. In the current contribution, a new design of the fin ray gripper is proposed with a smaller version for the fin ray gripper internally embedded. The kineto-static properties of the proposed fin ray gripper are analyzed computationally and experimentally. It is found that the proposed fin ray gripper shows variable stiffness properties along its length. It can adapt to different grasping situations with the choice of grasping location. Additionally, unbalanced grasping performances of the proposed fin ray gripper are explored, showing that it manages to grasp unbalanced objects with higher efficiency than conventional fin ray gripper. The current contribution provides a deeper understanding of soft passive grippers and figures out the possible role of unbalanced grasping in the real-world applications of soft grippers.
Lorentz attractor excitation-based structural damage identification using state space curvature reconstruction- enhanced transformer
Authors: Wang Xian , You Zengying , Pu Xiaoqing , Shao Nan , Xu Jiawen
Published: September 2024

Vibration-based structural damage identification has been widely investigated. Different from previous studies that analyze vibrational responses in time and frequency domains, a new Lorentz attractor excitation-based damage identification is becoming a novel strategy with the advantage of capturing the structure’s nonlinear dynamic effects. In this study, Lorentz attractor-based chaotic signals were employed as excitation signals for the structural damage identification of a frame structure. Nonlinear responses were recorded and damages of bolt looseness at different locations were considered. The structural damages could be revealed in the state-space plot of the responses. A state space curvature reconstruction method was introduced to enhance the key features of the nonlinear responses. A small-sample damage identification is performed using a deep learning algorithm—a transformer with an accuracy of 92.38%. The advantages of the proposed method over conventional deep learning algorithms were validated. The proposed method can be applied to health conditions identification of buildings, bridges, and trusses.
Bounded diffusing diffusivities: Brownian yet non-Gaussian diffusion
Authors: Luo Chengrong , Du Luchun , Guo Zixuan , Shi Hongda , Huang Feijie , Xiang Youlin , Guo Wei
Published: September 2024

Brownian yet non-Gaussian diffusion has been recently reported in a huge number of biological and soft matter systems. Meanwhile, an archetypal theoretical model called ‘diffusing diffusivities’ is proposed to interpret it. Based on this spirit of diffusing diffusivities, we extend the original diffusing diffusivities (with the unbounded exponential distribution) to the case that the diffusivity is constructed by a bounded stochastic process, i.e., corresponding diffusivities (with certain upper and lower bounds) obeying bounded power-law distribution. We demonstrate that Brownian yet non-Gaussian diffusion can be reproduced by this bounded diffusing diffusivities, via numerical simulations and analytic derivations. Specifically, the short-time distribution of displacement, as the indicator of the Brownian yet non-Gaussian diffusion, is derived analytically by means of superstatistical approach. This short-time distribution is distinct from the Laplace distribution that appears in the original model. The long-time Gaussian displacement distribution is obtained by utilizing the subordination concept. The bounded diffusing diffusivity here may be beneficial to further understanding the diffusive process of particles in complex and inhomogeneous environments. Our work enriches the diffusing diffusivity family and sheds new light on the concept of the Brownian yet non-Gaussian diffusion under stochastic process.
Enhancing efficiency of dye-sensitized solar cell using Mn or Ce doped and Co-doped ZnO photoanodes with lawsonia inermis natural dye
Authors: Kumar Aman , Kumar Suresh , Kundu Virender Singh , Hooda Kirti , Vohra Anil , Kumar Suresh , Podia Mohit , Jasrotia Rohit , Lakshmaiya Natrayan , Sillanpaa Mika
Published: September 2024

In the present research paper, Mn (transition metal) and Ce (rare earth metal) doped and co-doped ZnO nanoparticles were synthesized using a cost-effective sol–gel technique. As synthesized samples were characterized using x-ray diffraction and field emission scanning electron microscope to examine the structure and morphology respectively. The optical properties were examined by UV-Visible and photoluminescence spectroscopic techniques. The synthesized samples were used as photoanode for the fabrication of dye-sensitized solar cell (DSSC). The utilization of a photoanode, containing Mn and Ce doped and co-doped in ZnO, in DSSC leads to a significant enhancement in photovoltaic conversion efficiency with natural dye lawsonia inermis. Different combinations of Mn or Ce doped and co-doped ZnO nanoparticles were used for testing their effectiveness as photoanode in DSSC. It was observed that the efficiency for Mn and Ce co-doped ZnO photoanode-based DSSC was found to be 0.2118%, which is approximately a 750% increase as compared to bare ZnO photoanode based DSSC. The enhancement in the efficiency of DSSCs was due to the formation of a blocking layer by Mn ions which helps to stop the flow of electrons backward and the broadening of the spectrum region with the help of Ce ions using up/down conversion process also helps to achieve higher efficiency. This enhancement in the efficiency of DSSC may be attributed to the synergic effect of Mn and Ce.
Effect of surface state on wear performance of low alloy high strength marine steel
Authors: Wang Chaoyi , Yan Ling , Chang Xueting , An Wenrui
Published: September 2024

For ships sailing in polar ice regions, the marine steel not only has to be safely served at low temperatures but also may be abraded by hard sea ice. However, marine steel is inevitably affected by corrosion in seawater whose surface state and oxide type have a great influence on wear performance. To study the influence of the surface state on the wear performance of low alloy high-strength marine steel, the 460 MPa class high-strength marine steel was used as the research object to test the strength and plastic of the material. Further, γ-FeOOH oxide layer steel sample, untreated steel sample, and Fe3O4 oxide layer steel sample were prepared. The light interferometer and scanning electron microscope were used to characterize the microstructure morphology and wear scar morphology of the different steel samples. The test results show that different surface states have a great influence on the wear properties of Marine steel. The Fe3O4 steel sample with a dense and complete oxide layer has the lowest wear amount, its wear marks are the shiniest and narrowest, and the surface is mainly adhesive abrasion. The largest amount of wear is the relatively loose structure γ-FeOOH oxide steel sample, which has the smallest friction coefficient, its wear mechanism is mainly abrasive wear, and the surface has more furrows and pits. The wear resistance of untreated steel samples was between the above two.
Impact of adding Na2SiF6 on the crystal phase and copper valence state in glass ceramics made from leftover granite for use as architectural ornamentation
Authors: Ma Minghong , Huang Yongqian
Published: September 2024

The accumulation of granite waste can result in the occupation of a considerable amount of land resources. Using granite waste as glass ceramics for architectural decoration represents a potential solution to this issue. The microstructure, valence state, and crystalline phase of copper ions were examined by using X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and X-ray diffraction (XRD). The findings demonstrated that the concentration of Na2SiF6 affects the valence condition of Cu ions in crystallized glass. The crystalline phases of the sample containing 1.84 wt% Na2SiF6 consisted of forsterite (MgSiO3) and diopside (CaMgSi2O6), and the Cu+ accounted for 39.9% of the total Cu ions in the sample which showed a grey-black color. For the sample containing 3.67 wt% Na2SiF6, the crystalline phases consisted of richterite (Na, F) syn (Na (Na, Ca) Mg5Si8O22F2), cuprite (Cu2O), and forsterite, its Cu+ accounted for 39.9%, and the sample appeared orange-red. With the increase of Na2SiF6 content, the percentage of Cu+ in the total Cu ions showed an increasing trend, and the corresponding red color of the samples gradually deepened.
Formation mechanism of Hf-based ceramic particles in tungsten alloys
Authors: Li Jincheng , Wei Xiang , Gao Lin , Lou Longhui , Sun Benzhe , Liu Yongli
Published: September 2024

To meet the requirements of high strength of tungsten (W) based alloys at high temperature applied in the aerospace field, the preparation and formation of Hf-related ceramic particles in W were studied. It is found that the HfO2 phase with a size of about 500 nm was observed at the grain boundary in both W-0.26 wt.% HfC and W-0.25 wt.% HfH2-0.125 wt.% C systems. Further study of phase stability and thermodynamic properties of Hf(W)-O(C) compounds reveals that the HfO2 phase possesses the most stability of all the Hf-related compounds, and the oxidation of Hf is preferred to the carbonization. It is predicted that more stability of W base metal, higher temperature, and higher carbon concentration can reduce the formation of HfO2 while promoting the formation of the HfC particle phase.
Spreading modeling of prepreg tape used for manufacturing of variable angle tow composites
Authors: He Siyu , Feng Zhao , Zhang Qiang
Published: September 2024

Variable angle tow (VAT) laminates are gaining popularity for enhancing composite structure performance. Automated fiber placement (AFP) is an effective method for tailoring VAT laminates to boost manufacturing efficiency. However, traditional AFP equipment faces limitations, such as the inability to eliminate defects like gaps and overlaps due to a minimum steering radius. This study addresses these defects by examining the spreading behavior of prepreg tapes. A simplified Navier-Stokes equation-based model is developed to analyze the impact of pressure and temperature on tape spreading width. Experimental validation, conducted under conditions that simulate automated layup operations, demonstrated that the tapes can be significantly broadened by up to 30% with increased temperature and pressure. The experimental data is curve-fitted using the least square method, and the model shows a good fit with the results.
Comparison of high temperature oxidation behaviour of high speed steel and Hi-Cr steel
Authors: Li Wanli , Ou Yujing
Published: September 2024

High speed steel and Hi-Cr steel are widely used as one of the important materials for rolls. The oxide layer during rolling plays a key role in the service life of the rolls and the quality of the rolled material. Therefore, it is very important to study the oxidation behaviour of high speed steel and Hi-Cr steel. In this paper, the oxidation behaviour of HSS and Hi-Cr steel is compared in the range of 500-700°C. The oxidation kinetic curve of HSS is dominated by a parabolic law, while the oxidation kinetic curve of Hi-Cr steel is dominated by a logarithmic law. To analyse the effect of their oxidation products on the oxidation behaviour, V2O5 in high speed steel plays a destructive role in the oxide layer, while Cr2O3 in Hi-Cr steel can effectively reduce the thickness of the oxide layer.
Evaluation of the mechanical properties of stiffened composite panels under consideration of water load
Authors: Yang Junchao , Chen Xiangming , Wang Zhe , Zou Peng , Zhu Qiang
Published: September 2024

To meet the strength evaluation requirements of a typical stiffened composite panel of the lower fuselage of a new generation amphibious aircraft underwater load, the experimental testing technique and finite element analysis method were investigated. Firstly, according to the loading and support requirements of the typical stiffened composite lower fuselage panel, a testing device for combined axial and pneumatic loading was designed and developed. Then, a finite element model of the stiffened composite plate and the combined load testing device were created. Based on the experiments and finite element analysis, the static strength of the stiffened composite plate was verified to meet the load-bearing capacity requirements, and the strain behavior during loading was determined. Compared with the experimental results, the maximum strain error at the skin is 6.16%, and the maximum strain error at the stiffener is -11.6%. This confirms the effectiveness of the finite element model and also confirms that the test technique and equipment can accurately simulate in-plane axial loading and out-of-plane water loading. Finally, based on the validated finite element model, the load-bearing capacity of the stiffened composite panel under combined loads was predicted.
Study on quasi-static tensile mechanical properties of biomimetic helicoidal composite laminates
Authors: Huang Shutong , Jia Xiaoli , Liu Hengxiang , He Jianfeng , Yang Qingyu , Ke Liaoliang , Yang Jie , Kitipornchai Sritawat
Published: September 2024

Numerous biomaterials exhibit intricate helicoidal structures renowned for their exceptional toughness. This study drew inspiration from the collagen fiber structure found in the scales of coelacanths to design composite laminates featuring double helicoidal layup configurations with varying pitch angles. A damage evolution model with damage initiation and linear stiffness degradation based on the Hashin failure criterion was used to describe the damage behavior of the materials. The impact of varying pitch angles on the quasi-static tensile properties of double helicoidal composite laminates is investigated. The results show that the magnitude of the pitch angle has a significant effect on the tensile properties of the laminates, and the tensile modulus of double composite laminates is highest when the pitch angle is 90°.
Nonlinear damage dynamics modeling and characteristics simulation of bevel gear set
Authors: Hu Jiao , Tang Lun , Liu Xingshu , Shen Jian
Published: September 2024

As a key core device for power transmission in the main reducer of a helicopter, the bevel gear set affects the flight performance of the helicopter directly. A nonlinear damage dynamic model of bevel gear set was constructed using the centralized parameter method. The inherent characteristics and nonlinear behavior characteristics of bevel gear sets were studied, and the time-frequency domain characteristics under different health states were simulated. The fault response transmission law and fault mechanism of the system were deeply revealed, which provides guidance and support for the optimization design of helicopter transmission system and the diagnosis algorithms development.
Analysis of the temperature rise process of carbon ceramic axle-mounted brake disc
Authors: Qiao Qingfeng , Xia Mingchen
Published: September 2024

At present, high-speed train braking modules gradually adopt carbon ceramic brake discs. Based on the calculation results, the temperature simulation calculation of carbon ceramic brake disc for high-speed trains is of important engineering reference value for design and application. This paper established a finite element thermal simulation model based on the material properties of carbon-ceramic composite materials and the size and structural characteristics of the brake disc, and conducted a simulation analysis of the 400km/h emergency braking condition. After calculation, the carbon ceramic disc surface temperature reaches about 1250°C during the braking process, which does not exceed the material limit of 1350°C, and can adapt to the braking requirements of high-speed trains. The evolution rules of the temperature field and temperature value changes of the carbon ceramic shaft-mounted brake disc were further studied, and the general rules of disc temperature changes during emergency braking at 400km/h were summarized. The relevant content can provide a reference for the thermal analysis research of carbon ceramic axle-mounted brake disc.
Analysis of conductive filament heat transfer in TiO2-based RRAM device
Authors: Li Jing , Pan Jinyan , Huang Qiao , He Ruotong , Xie Lunbo
Published: September 2024

Resistive random access memory (RRAM) has developed into a new type of non-volatile memory that has attracted much attention for its high density and low power; TiO2 has been studied to make RRAM because of its high conductivity. Based on the COMSOL Multiphysics finite element method and domain decomposition method, an electrically-thermally coupled model of TiO2-based RRAM with oxygen vacancy (Vo) conduction mechanism is constructed, the formation and cutting process of RESET and SET conductive filament (CF) under different voltages is simulated. Moreover, the characteristics of the internal temperature distribution of the CF are explored. The results show that the RESET process is more sensitive to heat changes, the transverse direction thermal value of the CF is more obvious than the longitudinal direction, and the rate of change is faster. Additionally, the electric field induces the migration of the Vo in filament, which affects the enthalpy change of the device’s heat transfer and resistive properties. This is an important reference for a deeper understanding of the switching behavior of RRAM devices and the control mechanisms for thermal studies.
Design and performance research on metal-sprayed electrical heating films for aircraft wing anti-icing
Authors: Ding Yuanyuan , Li Zhimao , Ren Zhefan , Zhu Guangya , Bai Bin
Published: September 2024

Composite material, supercritical aircraft wings, and multi-electrical technology represent the future development trend of civil aircraft. However, domestically, the use of electrical heating for anti-icing on civil aircraft made of composite materials has not yet been implemented. In this study, focusing on the anti-icing technology of a specific aircraft wing leading edge, the article initially designs a metal thermal spraying circuit based on the thermal load distribution on the surface of the anti-icing area. Next, the research explores the resistive properties of the electrical heating film on the composite material wing leading edge, examining how the porosity and oxide content of the coating affect its resistivity. Finally, the metal thermal spray test is completed on the leading edge of the composite material aircraft wing. The test results indicate that the adherence and deposition rate of the coating on the leading edge of the aircraft wing are reliable. The resistivity of the heating film meets the performance specifications. The article develops an integrated metal thermal spray control method based on high-curvature composite materials, resulting in an electrical heating film with excellent shape adaptability, varying power density, and strong bonding, providing support for the domestic advancement of wing electrical heating anti-icing technology.
Innovative integration of maturity detection and robotic technology for enhanced litchi harvesting
Authors: Xiong Juntao , Huang Qiyin , Jiang Xinjing , Zhou Chengzhuo
Published: September 2024

An integrated approach marries an optimized YOLOv7 deep learning model with a 6-axis robotic arm, featuring a novel end-effector design, to elevate automated litchi harvesting. The model, refined with ACmix attention and Focal-EIoU loss functions, adeptly identifies litchi maturity across diverse orchard settings, overcoming challenges like variable lighting and occlusions. Rigorous field validations and real-world applications demonstrate the system’s efficacy, with an 85.7% success rate in precisely harvesting mature litchis. This fusion of cutting-edge image recognition with strategic mechanical innovation effectively mitigates labor shortages and enhances productivity, marking a significant leap forward in orchard automation.
Research on positioning accuracy of the swivel head of milling and turning complex machining center
Authors: Si Weizheng , Tang Jianhao , Liu Jianhua , Wei Zijun , Mao Luyao
Published: September 2024

This article focuses on the swivel head of a milling-turning complex machining center and establishes a geometric error model between the rotary axes based on the multi-body system theory and the homogeneous coordinate transformation method. The double ball bar (DBB) is used to identify the geometric errors of the machine tool swivel head position-independent by measuring circular trajectories. The impact of PIGEs on the measurement trajectory is simulated. The swivel head is rotated at four angles (B0°, B45°, B90°, B-15°), and the laser tracker is used to analyze and study the linear axis straightness, perpendicularity, and the center coordinates and plane errors of the swivel head movement along the XZ plane. A swivel head rotation accuracy test fixture is designed to correct the positioning accuracy of a swivel head with a 45° inclination of the rotation axis. The research results show that the fluctuation of the center plane degree of freedom of the swivel head moving along the XZ plane is small, and the maximum value is 0.0086mm. Under the 45° angle posture of the swivel head, both the center coordinate error value and the plane error value are the largest. The simulation results of the swivel head position error are fairly consistent with the center coordinate error of the swivel head plane movement. A backward tilt displacement of 0.01mm~0.015mm of the machine column during assembly can reduce the influence of the weight of the swivel head on the perpendicularity and straightness of the vertical reciprocating motion, and adding auxiliary support near the base of the swivel head zero position can reduce machine straightness error.
Research on airspace filtering algorithm for trackside train bearings based on GSC-MVDR
Authors: Yuan Ziyu , Liu Fang , Bao Xuewen , Ren Guangwen , Zeng Guoqiang , Liu Yongbin
Published: September 2024

Trackside Acoustic Detection Systems (TADS) employ microphone arrays installed on both sides of the railway tracks to collect sound signals emitted by wheelset bearings as trains pass by. These systems facilitate state monitoring and fault diagnosis through signal processing, offering capabilities such as non-contact measurement, low cost, and early warning of potential failures. However, the strong noise characteristics of trackside signals significantly impair diagnostic precision. To address this issue, this paper proposes a spatial filtering algorithm based on the Minimum Variance Distortion-less Response (MVDR) and the Generalized Sidelobe Canceller (GSC), achieving directional denoising. Additionally, the algorithm employs time-domain resampling techniques to correct the Doppler effect in signals.
Preparation of MnS/NiCo2S4 composite nanosheets self-supported electrode and the performance in water-system asymmetric supercapacitors
Authors: Wang Xiao , Ren Siheng , Kong Deqiang , Liu Chang , Wu Yuanhao
Published: September 2024

In this paper, the MnS@NiCo2S4 composite self-supporting electrode was designed and prepared with a mixture of nickel, cobalt, and manganese sulfide as the research object. The capacitance of the electrode can reach 2, 372.7 F g−1 at the current density of 1 A g−1, and the voltage window can also be widened to 0-0.6 V and maintains a multiplier performance of 62.1% at 10 A g−1. Following 5, 000 cycles of charging and discharging, the electrode exhibits a capacity retention of 78.2% relative to its initial capacity, with the coulombic efficiency consistently hovering around 100%. This performance indicates that the electrode can carry out stable and reversible electrochemical processes. A supercapacitor assembled with 1 M KOH as the electrolyte, activated carbon as the anode, and MnS/NiCo2S4 as the cathode, delivers an energy density of 46.9 W h kg−1. In the life test of the charge and discharge cycle, the discharge capacity after 10, 000 cycles is 89.2% of the initial capacity, indicating that the device has good cycle stability. This study provides an idea for the potential application of metal sulfide-based electrodes with wide potential windows and high electrochemical properties in water asymmetric supercapacitors.
Highly sensitive and chemically resistant moisture sensor based on polyether sulfone and polyimide composite membrane for power transformer oil
Authors: Zhu Bin , Deng Keqi , Li Xiaojuan , Wen Liguo , Shen Hongwei , Wu Dezhi
Published: September 2024

Moisture is the primary factor leading to the deterioration of transformer oil. Real-time detection of transformer oil moisture content holds significant importance to help power companies monitor the transformer’s operational status, track the change curve of the oil moisture content, identify water ingress causes, and implement preventive measures. However, transformer oil has the characteristics of low moisture content and complex chemical composition, which pose a substantial challenge for sensor monitoring, and require the prepared sensor to be chemically resistant and highly sensitive to moisture. To address these challenges, in this paper, a parallel plate oil moisture sensor with high sensitivity and high chemical resistance based on PES and PI was developed using the MEMS process. The sensor incorporates PES as the chemical resistance layer and PI as the moisture sensitivity layer. The parallel plate design not only optimizes sensitivity by effectively utilizing electric field lines but also allows the passage of water while isolating oil molecules, further enhancing the chemical resistance of the sensor. Experimental results in air demonstrate that the prototype sensor exhibits high sensitivity (~1.26 pF/% RH) across the full humidity range of 0-100% RH. Moreover, the sensor can withstand exposure to a wide range of chemical corrosive gases, including acetone, ammonia, etc. Tests in transformer oil reveal that the sensor has a resolution better than 200 ppm and can effectively measure moisture in the range of 0-1400 ppm, demonstrating very high sensitivity (4 pF/100 ppm) and rapid response (10/23 s).
Planar and non-planar hybrid printing trajectory generation method
Authors: Xu Li , Shi Zhiliang
Published: September 2024

Aiming at the problem of step effect, a planar and non-planar hybrid printing trajectory generation method is studied. The region with the inclination of the surface and horizontal plane of the model is extracted for non-planar printing, which can improve the surface printing quality of the model while controlling the printing time. The experimental results show that the proposed algorithm has good adaptability and can meet the requirements of engineering applications.