bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of current collector on the coupled electro-chemo-mechanical performance of graphite electrodes in LiBs
Authors: Li Xiaolin , Liu Jiahui , Gu Honghui , Jiang Hainan , Song Linlin , He Yaolong , Li Dawei
Published: October 2024

The current collector, one of the main components in the manufacture of composite electrodes, is mainly used to enhance the mechanical stability and improve the performance and cycle performance of the electrodes. During the electrochemical reaction, the lithium diffusion can induce compressive stress and affect the mechanical performance, lifespan, and performance of batteries. Therefore, this study analyzed the influence of copper foil on the mechanical response and degradation performance of electrodes. In addition, a mathematical model was developed to analyze the effect of copper foil on the stress–strain behavior of the electrodes. The results indicated that the stress and modulus of the graphite electrodes have a non-linear increase with the lithiation process. Based on those findings, utilizing a thinner and more compliant current collector could effectively mitigate the in-plane strain and the stress within electrodes. Thus, developing a thinner and softer copper foil could simultaneously enhance the mechanical properties and specific density of composite electrodes for the next-generation LiBs.
Numerical study of vehicle motion during water exit under combined lifting force and wave action
Authors: Huang Xin , Dai Yu , Zhu Xiang
Published: October 2024

During the retrieval process of the deep-sea mining vehicle (DSMV), the stability of the retrieval system is strongly influenced by the interaction between the vehicle body and the surrounding seawater due to the vehicle's complex shape and wave motion. Naturally, the negative side effects of significant changes in the vehicle's attitude and the water exit position can only increase retrieval's challenge. To investigate the characteristic of the flow field of the DSMV, this study employs the computational fluid dynamics method based on the Reynolds-averaged Navier–Stokes equations integrating the volume-of-fluid multiphase flow model with a fifth-order Stokes-wave model to explore the attitude and displacement changes of the vehicle during the water exit process in the ocean wave environment. The results indicate that the wave phase and lifting force are the major effect factors in the DSMV's water exit process. An appropriate lifting force under a specific wave phase can effectively reduce attitude changes and positional drift of the DSMV during water exit, thereby enhancing recovery efficiency and stability.
Numerical analysis of water injection in coal seams under mining influence
Authors: Liu Chun , Man Zhongyi , Li Maolin , Cha Jian , Dai Kang
Published: October 2024

This study investigates the diffusion characteristics and optimization of borehole water injection in the 3# coal seam of Licun Coal Mine under mining influence. The distribution of stress and permeability ahead of working face using FLAC3D combined COMSOL Multiphysics. The influence of distances between the borehole along with the diameters of the boreholes on the stress distribution around the borehole is studied. Additionally, the diffusion characteristics of coal seam water injection are analyzed under various parameters. The study found that borehole proximity to the working face significantly enhances stress relief and permeability, while borehole diameter has a minor impact. Simulation results from COMSOL Multiphysics indicated that increasing injection pressure significantly improves seepage velocity and wetting range, though borehole diameter effects remain negligible. Optimal water injection parameters were identified, suggesting that the most effective water injection occurs at a borehole 3 m from the working face, with a diameter of 0.11 m and an injection pressure of 10 MPa, achieving saturation within 48 h. This research contributes to the theoretical and practical understanding of optimizing borehole water injection in complex geological settings and thick coal seams.
Performance evaluation of machine learning algorithms in predicting machining responses of superalloys
Authors: Bhowmik Abhijit , Praveen K. N. Raja , Bhosle Nilesh , Gagneja Kunal , Talib Zunirah Mohd , Chohan Jasgurpreet Singh , Alkhayyat Ahmed , Ramudu M. Janaki , Santhosh A. Johnson
Published: October 2024

This study explores the application of machine learning algorithms—gene expression programming (GEP), adaptive neuro-fuzzy inference system (ANFIS), and artificial neural networks (ANN)—to predict machining responses during the milling of Inconel 690, a superalloy known for its exceptional mechanical properties and oxidation resistance. Machining Inconel 690 presents significant challenges due to its toughness and work-hardening tendencies, which can lead to rapid tool wear and poor surface finish. Traditional optimization methods often rely on empirical models and trial-and-error approaches, which are time-consuming and costly. In contrast, machine learning techniques can effectively model complex, nonlinear relationships between machining parameters and performance outcomes, such as surface roughness, cutting force, and cutting temperature. This study employs statistical metrics, including Root mean square error (RMSE), coefficient of determination (R2), and mean absolute percentage error (MAPE), to determine the predictive performance of the models. The results show that the GEP model achieved an R2 ranging from 0.944 572 to 0.992 999, with an RMSE between 0.015 527% and 0.694 523% and a MAPE ranging from 1.452 397% to 4.947 892%. ANFIS and ANN also demonstrated strong predictive capabilities, although GEP outperformed them. The importance of this study lies in its demonstration of advanced AI techniques as effective tools for optimizing machining processes, ultimately contributing to improved efficiency and quality in manufacturing superalloys.
Subsoil testing required to detect the rundown of soil potassium to deficient levels for wheat production on loam-textured soils
Authors: Scanlan Craig A. , Bell Richard , Cheng Miaomiao , Boyes Tim
Published: October 2024

Context Long-term negative potassium (K) balances in crop production have depleted soil K levels in Western Australia (WA). Previous research has focussed on sand-textured soils, but recently, monitoring of crops grown on loam-textured soils has shown deficient or marginal shoot K concentrations where Colwell K 0–10 cm is above current critical levels. Aims The aims were to examine whether grain yield responses to fertiliser K can be detected on loam-textured soils and if soil test calibration curves can be identified for these soils. Methods Eight field trials were conducted with wheat on loam-textured soils. The same experimental design was used at all sites; six levels of K applied at sowing, from 0 to 200 kg K ha−1 with one treatment including a split application. Soil and plant test calibration curves were modelled using measurements from the trials. Key results Grain yield responses of 0.69 to 1.37 t ha−1 to fertiliser K (P < 0.05) occurred in 4 of 8 trials. Relative yield was closely related to soil exchangeable K and the goodness of fit of the soil test calibration curves increased as the depth of sampling increased. The best soil test calibration curve was for sampling 0–40 cm. Conclusions This research confirms that on some loam-textured soils, yield loss is occurring to K deficiency if no K fertiliser is applied. Implications As soil K reserves are run down, soil sampling at 0–40 cm on loam-textured soils will provide the most accurate monitoring of soil K deficiency for wheat production.
Using quick response codes to access digital health resources in the general practice waiting room
Authors: Hu Elizabeth P. , McDonald Cassie E. , Zhou Yida , Jakanovski Philip , Lau Phyllis
Published: October 2024

Background Quick response (QR) codes are an established method of communication in today’s society. However, the role of QR codes for linking to health information in general practice waiting areas has not yet been explored. Methods This mixed-methods study used both quantitative data measuring QR scans and qualitative data from follow-up semi-structured interviews with visitors to two general practice waiting areas to determine access to an online health information site and their experience of using the QR code. The technology acceptance model was used to guide the interview questions. Quantitative data were analysed descriptively, and qualitative data were analysed thematically using an inductive approach. Results A total of 263 QR scans were recorded across the two sites between October 2022 and October 2023. Twelve participants were interviewed. Eleven themes were identified; six were categorised as facilitators and five were barriers to QR code engagement. Motivation for engagement included boredom and curiosity. Facilitators for engaging with the QR code included familiarity secondary to the recent COVID-19 pandemic, benefits of accessing potentially sensitive information with anonymity, convenience of revisiting later and reduced paper waste. Barriers included size and location of the QR code as a limiting factor to engagement, waiting room wait time, privacy and security concerns, and the potential to exclude those without access to technology or those with low technological literacy. Conclusion Using QR codes in the general practice waiting area is a convenient method of presenting health information to visitors and patients. Our findings indicate that this may be an appropriate method to share health information in waiting areas. Facilitators and barriers identified in this study may assist with optimising engagement with health information via QR codes while waiting for appointments.
Exploring the evolution of the concept of liberty in the U.S. presidential inaugurals
Authors: Giménez-Moreno Rosa , Llàcer Eusebio V.
Published: October 2024

As daily news unveils, fundamental human values such as equality and liberty can be expressed through various terms influenced by multiple factors, reaching significant levels of disparity, ambiguity and controversy, particularly in specific socio-political contexts. This article employs advanced corpus analysis tools to examine the lexical and semantic configuration of the “right to liberty” as expressed in the U.S. Declaration of Independence and as North American presidents have transmitted it throughout their presidential inaugural addresses. The corpus of speeches is analyzed diachronically to identify the prevalent terms, connotations, and associated semantic categories and observe their differences and evolution. This research provides a comprehensive understanding of the concept of liberty in this context and highlights its startling malleability in American politics.
Conceptualising meso translation policy
Authors: Wang Wanhong
Published: October 2024

Like language policy, translation policy is a complex adaptive phenomenon where multiple agents interact
dynamically at diverse levels and affect how principles such as equality, inclusion, and non-discrimination are implemented at
concrete, structural levels. While a fair amount of work has been done on top-down and bottom-up translation policy, more research
about meso-level translation policy is needed to better understand this topic. This study thus seeks to show how meso-level agency
needs to be taken into consideration; in particular, the complex interplays between meso-level agency and structural factors in
policymaking and appropriation processes. Taking two Toronto hospitals as examples, this study demonstrates how hospitals can be
conceptualised at a meso-level as collective agents. It examines the complexity of their agentive roles and elucidates their
exertion of agentive power in order to explore meso complexity, and to assess the subsequent impact on both policy outcomes and
people’s lives. To do so, a framework of parameters influencing, if not determining, the effectiveness of public service
translation and interpreting provision is proposed. It is then used in combination with an existing tripartite framework of
translation policy to develop a more fine-grained and holistic understanding of translation policy in public service settings.
Electronic states bound by repulsive potentials in graphene irradiated by a circularly polarized electromagnetic field
Authors: Kibis O V , Boev M V , Iorsh I V , Kovalev V M
Published: October 2024

In the framework of the Floquet theory of periodically driven quantum systems, it is demonstrated that irradiation of graphene by a circularly polarized electromagnetic field induces an attractive area in the core of repulsive potentials. Consequently, the quasi-stationary electron states bound by the repulsive potentials appear. The difference between such field-induced states in graphene and usual systems with the parabolic dispersion of electrons is discussed and possible manifestations of these states in electronic transport and optical spectra of graphene are considered.
Evidence for nematic fluctuations in FeSe superconductor: a 57Fe Mössbauer spectroscopy study
Authors: Hu Shixin , Xue Jijun , Wang Xiaoying , Pang Hua
Published: October 2024

There has been controversy about the driving force of the nematic order in the FeSe superconductor. Here, we present a detailed study of the 57Fe Mössbauer spectra of FeSe single-crystal powders, focusing on the temperature dependences of the hyperfine parameters in the vicinity of the nematic transition temperature, T
s ∼ 90 K. The nematicity-induced splitting of d
xz and d
yz bands, obtained from the anomalous increase in quadrupole splitting near T
s, starts at 143 K. The temperature evolution of the lattice dynamics, deduced from the recoilless fractions and second-order Doppler shifts, is found to undergo successively two segments of phonon-softening (160 K–105 K) and phonon-hardening (105 K–90 K), related to the appearance of local orthorhombic distortions above T
s and the establishing way of the associated nematic correlations. Analysis of the linewidths shows that spin fluctuations occur not only below 70 K but also across T
s (105 K–70 K), accompanied by the non-Fermi liquid behavior of the electrons. The results demonstrate the strong interactions between lattice, spin, and electron degrees of freedom in the vicinity of T
s and that the lattice degrees of freedom may play an essential role in driving the nematic order for FeSe.
Theoretical insights into off-stoichiometric Zr

(
x
)

Ti

(
1
−
x
)

IrSb half-Heusler alloys: a first principle calculations
Authors: Hadbi Mohammed , Demmouche Kamel , Eddine Mellah Djallal , Coutinho Jose
Published: October 2024

This study presents a theoretical investigation into the phase stability, electronic, and optical properties of off-stoichiometric

Zr

x

Ti

1
−
x

IrSb

(x = 0, 0.0625, 0.1875, 0.25, 0.50, 0.75, 1) compounds. Using first-principles calculations, we explore how varying Zr and Ti concentrations can tune the electronic and optical properties of these half-Heusler alloys. The Structural, optical, and electronic properties were meticulously analyzed with both the GGA-PBE and Meta-GGA-SCAN approximations, as implemented in the Vienna Ab initio Simulation Package (VASP). The dynamical stability of these compounds was assessed using the Phonopy package. Our findings reveal that these alloys exhibit semiconductor behavior with tunable band gaps, and their optical properties show significant variation across different compositions, particularly in the visible light range. The compounds also demonstrate robust dynamical stability, indicating their potential for practical applications in electronic and optoelectronic devices. These results underscore the versatility of

Zr

x

Ti

1
−
x

IrSb

alloys and highlight their promise for next-generation technology.
Bruggeman homogenization of a particulate composite material comprising truncated spheres and spheroids
Authors: Iga-Buitrón Héctor M , Mackay Tom G , Lakhtakia Akhlesh
Published: October 2024

Closed-form expressions were established for depolarization dyadics for a truncated sphere and a truncated spheroid, both electrically small, immersed in a uniaxial dielectric ambient medium. These depolarization dyadics were used to develop the Bruggeman homogenization formalism to predict the relative permittivity dyadic of a homogenized composite material (HCM) arising from a randomly distributed mixture of oriented particles shaped as truncated spheres and spheroids. Unlike other homogenization formalisms, most notably the Maxwell Garnett formalism, the Bruggeman formalism is not restricted to composites containing dilute volume fractions of constituent particles. Numerical investigations highlighted the anisotropy of the HCM and its relation to the shapes of the constituent particles and their volume fractions. Specifically, greater degrees of HCM anisotropy arise from constituent particles whose shapes deviate more from spherical, especially for mid-range volume fractions.
A method for measuring hairline length and discriminating hairline recession grades based on the BiSeNet model
Authors: Ai Yuhua , Wei Guoliang , Wu Junke , Liu Shuting , Chen Bo , Zhang Zhenyu , Li Qimin
Published: October 2024

Hair plays an important role in a person’s appearance. According to a survey by the World Health Organization, approximately 70% of adults have scalp and hair problems. Doctors currently make hairline recession diagnoses based on hair loss criteria, but this approach is subjective. This paper proposes a novel method for objectively assessing hairline recession grades. First, the Bilateral Segmentation Network model is utilized to obtain a facial segmentation image. Second, this paper utilizes the connected components method to improve the facial segmentation results. Next, the labeling key points method is used to extract part of the features of the eyebrow and facial region and calculate the related values. Finally, the judgment of hairline length and hairline recession grade is realized by combining these features with camera calibration. In this paper, front-face images of 50 volunteers were collected for hairline recession grade determination. The judgment results of expert doctors on hairline length and hairline recession grade were compared with the judgment results of this method. The results showed a 1.3 cm difference in the average length of the hairline and about 80% similarity in hairline recession grade judgments. In conclusion, using machine vision methods to measure the height of the hairline provides objective and repeatable results.
A robust and efficient cubature Kalman filter based on the variational Bayesian method and its application in target tracking
Authors: Li Xiaonan , Ma Ping , Wen Xu , Chao Tao , Yang Ming
Published: October 2024

In this paper, we propose a robust cubature Kalman filter (CKF) for nonlinear state-space models with unknown state and measurement noise covariance matrix. We study situations in which sensors are independent of each other. Therefore, the unknown measurement noise variance is modeled as an unknown inverse gamma (IG) distribution. The Gaussian-Student-t-inverse-Wishart (GSTIW) mixture distribution is used to model the one-step prediction distribution. Modeling generates numerous unknown parameters. Therefore, we adopt the statistical linearization method to linearize the observation function and then estimate the state and parameters separately to reduce the computational burden of estimating unknown parameters, significantly improving the algorithm’s efficiency. Finally, using the variational Bayesian method, a novel and efficient robust CKF based on the IG distribution and GSTIW mixture distributions (IG-GSTIW-CKF) is obtained. Simulation and experimental results show that the proposed method has better estimation accuracy than several advanced algorithms when sensors are independent. In addition, the efficiency of the proposed algorithm is significantly higher than that of other CKF-based methods.
Demonstrating Brownian motion and estimating Avogadro’s number using simple tools: a practical guide for students
Authors: Cahill Gary
Published: October 2024

Brownian motion provides crucial observational evidence for the kinetic molecular theory by demonstrating the random perpetual movement of small particles. This phenomenon underscores the existence and behaviour of atoms and molecules, fundamentally supporting our current understanding of molecular kinetic theory. Remarkably, in 1905 Albert Einstein was able to predict this motion exactly purely from a theoretical point of view and in 1908 Jean Perrin provided experimental proof. This provided experimental proof of the existence of atoms and molecules. This paper outlines a method to demonstrate and record Brownian motion using a drop of homogenised low fat milk, a microscope and a mobile phone. The captured video files can be analysed with Physics Tracker software, allowing for the estimation of Avogadro’s number.
Measuring the Q-factor of a series RLC circuit with a smartphone as a function generator
Authors: Ortuño-Molina Santiago , Muñoz-Pérez Francisco M , Garmendía-Martínez Adrián , Castro-Palacio Juan C , Monsoriu Juan A
Published: October 2024

The use of smartphones as tools for teaching circuits has revolutionized the educational practice in this field. Free applications allow to measure the acoustic intensity with a smartphone and to generate an acoustic signal with a specific frequency. In this way, students turn their mobile devices into function generators and oscilloscopes, respectively, through the audio port. This innovation facilitates the implementation of hands-on experiments with basic circuits. This work implements a smartphone as a function generator connected to a series RLC circuit to obtain the average dissipated power and the corresponding Q-factor. A very good agreement is obtained between theoretical and experimental results.
One-dimensional magnetic excitonic insulators
Authors: Liu Jing , Qu Hongwei , Li Yuanchang
Published: October 2024

Dimensionality significantly affects exciton production and condensation. Despite the report of excitonic instability in one-dimensional materials, it remains unclear whether these spontaneously produced excitons can form Bose–Einstein condensates. In this work, we first prove statistically that one-dimensional condensation exists when the spontaneously generated excitons are thought of as an ideal neutral Bose gas, which is quite different from the inability of free bosons to condense. We then derive a general expression for the critical temperature in different dimensions and find that the critical temperature increases with decreasing dimension. We finally predict by first-principles GW-Bethe–Salpeter equation calculations that experimentally accessible single-chain staircase Scandocene and Chromocene wires are an antiferromagnetic spin-triplet excitonic insulator and a ferromagnetic half-excitonic insulator, respectively.
Flexible Krylov methods for group sparsity regularization
Authors: Chung Julianne , Sabaté Landman Malena
Published: October 2024

This paper introduces new solvers for efficiently computing solutions to large-scale inverse problems with group sparsity regularization, including both non-overlapping and overlapping groups. Group sparsity regularization refers to a type of structured sparsity regularization, where the goal is to impose additional structure in the regularization process by assigning variables to predefined groups that may represent graph or network structures. Special cases of group sparsity regularization include ℓ
1 and isotropic total variation regularization. In this work, we develop hybrid projection methods based on flexible Krylov subspaces, where we first recast the group sparsity regularization term as a sequence of 2-norm penalization terms using adaptive regularization matrices in an iterative reweighted norm fashion. Then we exploit flexible preconditioning techniques to efficiently incorporate the weight updates. The main advantages of these methods are that they are computationally efficient (leveraging the advantages of flexible methods), they are general (and therefore very easily adaptable to new regularization term choices), and they are able to select the regularization parameters automatically and adaptively (exploiting the advantages of hybrid methods). Extensions to multiple regularization terms and solution decomposition frameworks (e.g. for anomaly detection) are described, and a variety of numerical examples demonstrate both the efficiency and accuracy of the proposed approaches compared to existing solvers.
Self-diffusion in Germanium-rich liquid Germanium-Nickel investigated by quasielastic neutron scattering
Authors: Weis H , Kargl F , Yang F , Unruh T , Koza M M , Meyer A
Published: October 2024

We report atomic dynamics in liquid Ge98Ni2 measured using quasielastic neutron scattering. Isotopic substitution enabled to separately determine Ge and Ni self-diffusion with high accuracy. The Ge self-diffusion coefficient in liquid Ge98Ni2 is equal within error bars to that in pure liquid Ge. However, the Ni self-diffusion coefficient lies at least 30% below the Ge self-diffusion coefficient. This behaviour differs from previously reported atomic dynamics in Ge-rich GeAu, GeSi, GeIn and GeCe melts, where no separation of the self-diffusion coefficients between the minor component and Ge is observed. The change of the atomic dynamics already at an addition of 2 at% Ni points to electronic and chemical origins in Ge98Ni2. Moreover, the slower self-diffusion of the minor component compared to Ge might be associated with two different local structural environments, as observed in Ge-Ni alloys at higher Ni concentration.
A quad-polarization reconfigurable transmitarray antenna with beam-scanning and reconfigurable polarization capabilities
Authors: Tian Xiuwen , Song Lizhong
Published: October 2024

In this paper, a novel quad-polarized electronically reconfigurable transmitarray antenna(QRTA) is proposed, which can actively switch among four linear-polarization modes and steer beam-scanning in these polarization modes. The QRTA element follows a receiving-transmitting structure. Its receiver or transmitter is composed of four rotationally symmetric patches and a coupling patch. Four rotationally symmetric patches generate x- and y-polarization modes, while coupling patches on the top and bottom layers of the QRTA element are designed to synthesize x-, 45◦-, y-, and 135◦-polarization modes. The QRTA element utilizes a reverse symmetry current method to achieve a 180◦ phase difference in the radiated electromagnetic waves. By manipulating the state of the p-i-n diodes, the proposed QRTA element can achieve four LP functions and a 1-bit phase shift. Based on the proposed novel QRTA element, a 10 × 10 elements QRTA prototype is fabricated and measured. The measured results demonstrate that the proposed QRTA can electronically switch between four LP modes and achieve beam-scanning in those LP modes. The proposed QRTA shows several advantages, including low cost, multi-polarization capability, high gain, and beam-scanning, which means that it can enhance the polarization capabilities and intelligence of wireless communication systems.
Effect of dark matter interaction on hybrid star in the light of the recent astrophysical observations
Authors: Pal Suman , Chaudhuri Gargi
Published: October 2024

We have explored the effect of dark matter interaction on hybrid star (HS) in the light of recent astrophysical observational constraints. The presence of dark matter is assumed to be there in both the hadron as well as the quark sector. The dark matter particle interacts with both hadron and quark matter through the exchange of a scalar as well as a vector meson. The equation of state (EOS) of the hadron part is computed using the NL3 version of the relativistic mean field(RMF) model, whereas the quark part is taken care of using the well-known MIT Bag model with the vector interaction. We investigate the effect of the dark matter density and the mass of the dark matter particle on various observables like mass, radius, tidal deformability of the dark matter admixed hybrid star(DMAHS).
In this study, we have noted an intriguing aspect that is the speed of sound in the DMAHS is insensitive to both the mass as well as the density of dark matter. We also observe a striking similarity in the variation of transition mass and its corresponding radius, as well as the maximum mass of neutron stars, with dark matter density and mass. We employ observational constraints from neutron stars to narrow down the allowed range of the parameters of dark matter.
Constraining burdened PBHs with gravitational waves
Authors: Barman Basabendu , Loho Kousik , Zapata Óscar
Published: October 2024

We investigate the implications of memory burden on the gravitational wave (GW) spectrum arising from the Hawking evaporation of light primordial black holes (PBHs). By considering both rotating (Kerr) and non-rotating (Schwarzschild) PBHs, we demonstrate that the overproduction of primordial GWs from burdened PBHs could impose stringent constraints on the parameters governing backreaction effects. These constraints, derived from ΔNeffmeasurements by Planck and prospective experiments such as CMB-S4 and CMB-HD, offer novel insights into the impact of memory burden on PBH dynamics.
Embedded Star Catalog Calculation Tool for Autonomous Star Trackers
Authors: Bürger Karoline C. , Fialho Fábio de O. , Aykroyd Christopher R. B.
Published: October 2024

Autonomous star trackers are crucial attitude sensors for spacecraft three-axis control. They are the most accurate commercial-off-the-shelf sensors available. An autonomous star tracker is an optoelectronic device that autonomously determines the spacecraft’s attitude, using an embedded star catalog that is compared to in-orbit images to perform stellar field recognition. This work presents a computational tool to calculate the embedded star catalog for any specified star sensor. To optimize the star sensor design, the tool developed provides users with sensor accuracy analysis regarding the observed starfield.
Identification of Z Cam's Historical Counterpart: The Quest for an Ancient Nova
Authors: Yang Bo-Shun , Hoffmann Susanne M.
Published: October 2024

In recent astronomical discussions, attempts have been made to link the known dwarf nova Z Cam to historical celestial events, particularly the “guest star” phenomenon reported in China in 77 BCE. Despite other suggestions and the problems with regard to the location of the event in 77 BCE, its identification with Z Cam is used in the Variable Star Index of the AAVSO and in several research papers that aim to derive knowledge on the evolution of cataclysmic variables. Through the reconstruction of the super-constellation of the Purple Palace in the Han Dynasty, we found that Z Cam is actually located outside this enclosure, contradicting the records of the 77 BCE guest star being “within the Purple Palace.” With newly found text versions of the guest star in 77 BCE, we narrowed down the position given therein. Combining with a new analysis of accompanying divination text leads to the conclusion that this guest star was actually a comet. Finally, through meticulous examination and comparison, we conclude that the guest star of 369 CE appears the most plausible candidate for Z Cam’s historical counterpart, aligning with both textual evidence and modern astronomical observations.
Saddle-to-saddle dynamics in diagonal linear networks*
Authors: Pesme Scott , Flammarion Nicolas
Published: October 2024

In this paper we fully describe the trajectory of gradient flow over two-layer diagonal linear networks for the regression setting in the limit of vanishing initialisation. We show that the limiting flow successively jumps from a saddle of the training loss to another until reaching the minimum

ℓ
1

-norm solution. We explicitly characterise the visited saddles as well as the jump times through a recursive algorithm reminiscent of the LARS algorithm used for computing the Lasso path. Starting from the zero vector, coordinates are successively activated until the minimum

ℓ
1

-norm solution is recovered, revealing an incremental learning. Our proof leverages a convenient arc-length time-reparametrisation which enables to keep track of the transitions between the jumps. Our analysis requires negligible assumptions on the data, applies to both under and overparametrised settings and covers complex cases where there is no monotonicity of the number of active coordinates. We provide numerical experiments to support our findings.
Research on cooperative game optimization scheduling of multi-micro-networks considering carbon trading
Authors: An Yinping , Meng Xiangping , Jia Youbo , Cheng Yue , Liu Fang
Published: October 2024

Developing a clean, low-carbon, secure, and efficient energy system based on dual carbon and transitioning to a new energy-dominated power system is a crucial step for China’s energy evolution and path to carbon neutrality. This study examines multi-microgrid collaboration under carbon trading to encourage local energy consumption and drive the operation of a low-carbon economy. A cooperative game strategy-based scheduling approach is proposed. Initially, the operational framework for a multi-microgrid system with carbon capture capability is defined, along with a model for low-carbon operation across multiple energy sources. Subsequently, power trading is facilitated within and between sub-microgrids and distribution networks to enhance the economic viability of the multi-microgrid setup. The study outlines the multi-microgrid system, presents typical power supply models, introduces the core concept of cooperative games, and establishes a grid-connected multi-microgrid scheduling cooperative game model. The ADMM algorithm is employed to address cost minimization and benefit maximization challenges within the multi-microgrid alliance. The efficacy of this strategy is evidenced through a numerical illustration.
Application of model predictive control scheme for piezoelectric ceramic micro-displacement
Authors: Kang Dianyu , Xue Wei , Hu Siqi , Xiao Jing
Published: October 2024

Currently, in the domain of micro-control technology, many operations need to meet the standard of nanometer-level positioning. As a high-precision micro-displacement element, piezoelectric ceramics are widely used in the field of micro-control due to their characteristics such as no need for transmission devices, high resolution, large output force, small size, and fast response speed. However, the inherent hysteresis nonlinearity of piezoelectric ceramics can lead to decreased displacement accuracy, oscillation, and even system instability. Therefore, eliminating the influence of nonlinear characteristics and improving displacement accuracy possess significant practical importance. In this paper, a model predictive control scheme is designed, which achieves faster response speed and higher accuracy compared to traditional control methods such as Proportional Integral Derivative control. Relevant simulations and tests have been conducted. In this scheme, hysteresis nonlinearity is first modeled and then compensated through feedforward, thereby simplifying the displacement control of piezoelectric ceramics into a more manageable linear problem. Subsequently, a linear model predictive control method is adopted to control the entire system. Both simulation and experimental results have verified the effectiveness of this control method.
Process optimization of wet etching for split gate trench MOSFET
Authors: Xi Lan Chen , Jin Chao , Gong Yu Bing , Li Wang Hong , Fan Li Ping
Published: October 2024

In this paper, the influence of etching technology on the performance of Split Gate Trench (SGT) MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistor) is studied, and the significance and contribution of these improvements in the fields of mechatronics, robotics and control systems are discussed. Etching can be categorized into wet etching and dry etching, with wet etching being widely used for etching the gates of SGT MOSFETs. Due to the isotropic nature of wet etching, issues such as undercutting, trenching, and insufficient link-up region length can arise, leading to short circuits between the gate and the source. The improvement of this problem directly promotes the enhancement of mechatronics system efficiency, the improvement of robot dynamic performance and accuracy, and the realization of efficient control strategies in control systems. By optimizing the process flow to enhance the adhesion of photoresist, increase the density of the HDP (High Density Plasma) deposited oxide film, and adjust the etching rate and frequency of wet etching, it is possible to mitigate the issues of isotropy and insufficient precision in wet etching. These improvements address failure phenomena and enhance product yield.
Characteristic analysis of rain-wind induced stay-cable vibration based on friction damper in field observation
Authors: Wu Xiaoxi
Published: October 2024

Both domestic and foreign scholars have developed various friction dampers with good characteristics. The primary types of friction dampers include conventional friction dampers, Pall friction dampers, Sumitomo friction dampers, and Centripetal friction dampers. The components of these dampers will slip or deform under load effect when the energy is consumed by friction. As the structural vibration period increases while the external energy input decreases, the vibration amplitude is reduced. This vibration reduction method is widely used in the automotive industry. Most of the hysteresis models of dampers are similar to rectangular shapes, making the selection of an accurate initial sliding force crucial for the rectangular hysteresis model. Based on the effective data collected from the field observation test, a self-made friction damper, which has a good vibration reduction effect, was used to observe rain-wind induced stay-cable vibration at Dongting Lake Bridge in Yueyang, Hunan Province. Accordingly, some suggestions are put forward for the research work on rain-wind-induced vibration.
Research on smoke cleaning based on Mg(OH)2/NaClO2 seawater solution
Authors: Guo Xu , Lu Yulei , Gong Xiwu
Published: October 2024

Ship exhaust emissions contain a large amount of sulfur oxides and nitrogen oxides, which have attracted widespread attention from the international community for their pollution of the atmospheric environment. In order to reduce the emissions of these pollutants, the International Maritime Organization (IMO) and other national institutions have established strict emission standards and promoted the research and application of ship exhaust desulfurization and denitrification technology. Experimental and simulation analyses were conducted on the denitrification effect of Mg(OH)2/NaClO2 solution using a cyclic spray method. Simulation analysis was carried out using cyclic spraying. The experiment compared the reaction degree and reaction time of NO in NaClO2 seawater, NaClO2 water, and Mg(OH)2/NaClO2 marine solution. The experimental result is that in the process of cyclic spray, the removal rate of NO by these three solutions can reach 100%. The reaction time of NO is 71, 86, and 90 minutes, respectively. Under the same conditions, the simulation results showed that the reaction rate of NaClO2 water solution with NO was faster, followed by NaClO2 seawater solution. The reaction rate of Mg(OH)2/NaClO2 seawater solution with NO was the slowest of the three. When the pH value exceeds 7, it effectively inhibits the production of ClO2 gas by NaClO2. The removal rate of Mg(OH)2/NaClO2 seawater solution is directly proportional to the initial concentration of NaClO2. In addition, it could be seen from the simulation cloud diagram that the removal speed of NO in the spray reactor slows down as the concentration of NO increases.
Simulation study on submarine trench gravel dumping under the influence of hydrodynamics
Authors: Wang Xiaohua , Zhu Ping , Jiang Yonghui
Published: October 2024

Gravel drift under the hydrodynamic effect is a significant problem during gravel dumping operations in coastal areas, which has a great impact on construction efficiency. Based on the Zhangpu submarine pipeline project, this paper investigated the drift distance and underwater distribution characteristics of gravel during the process of submarine trench gravel dumping under the influence of hydrodynamics by using the computational fluid dynamics (CFD) method. The results show that the greater the water depth and current speed is, the farther the drift distance of gravel along the current direction is. The water current has the most significant effect on the underwater distribution of gravel. The larger the current velocity is, the larger the underwater distribution width of gravel after sinking to the bottom is, and the larger the loss rate of gravel which has not been thrown to the required range is. The construction work should be avoided under high current speed conditions when carrying out gravel dumping.
Ship hydrodynamic performance analysis and model construction based on CFD method
Authors: Zhang Hangming , Zhang Yongtao
Published: October 2024

CFD method has the advantages of high forecast accuracy, wide applicability, strong stability of calculation results, and low cost, and nowadays it has been widely used in various fields. The CFD method has many advantages when applied to ship hydrodynamic performance analysis, specifically to ship hydrodynamic performance prediction, problem mechanism research, and performance optimization. Based on this, this paper utilizes the CFD method to carry out a model analysis of ship hydrodynamic performance. By analyzing the propeller efficiency, the reasoning force and torque of the double propeller in the symmetric case are decreased. However, the efficiency is improved by 1.4% compared with the asymmetric case, which shows that the method adopted in this paper can effectively improve the ship hydrodynamic force. Through the above research, we aim to provide a certain reference for the improvement of ship hydrodynamic performance.
Resistance performance study and hull form optimization of aquaculture vessel by CFD method
Authors: Tao Yanwu , Zhu Renqing , Gu Jiayang , Li Zhiyu
Published: October 2024

Aquaculture vessel is a novel form of deep-sea aquaculture engineering with a wide range of applications. The resistance performance of the aquaculture vessel was studied by the computational fluid dynamics method and compared with the experiment. Two optimization schemes, namely, straight bow and bulbous bow, are designed to optimize the original design, focusing on improving the bow profile. The effectiveness of the two optimization schemes in terms of resistance reduction was evaluated by the CFD method. The resistance calculated by numerical calculations was found to be in good agreement with the experimental results. The bulbous bow scheme reduces resistance better than the upright scheme, with a resistance reduction of 2.92% at 11 kn. This study can guide the overall design of an aquaculture vessel.
Research and application of the method of measuring the effective utilization coefficient of irrigation water on farmland
Authors: Fan Qunfang , Long Xiaofei , Wang Xinghan , Guo Wei
Published: October 2024

Under the guidance of the new water management idea of “water conservation priority, spatial balance, system management, and two-handed effort,” the National Water Conservation Action Plan released in 2019 puts forward the key task requirements of “double control of total intensity,” in which the effective utilization coefficient of irrigation water in farmland is one of the indicators of water intensity control. The effective utilization coefficient of irrigation water is one of the water intensity control indicators. At present, there are practical difficulties in measuring the effective utilization coefficient of irrigation water in farmland, such as the low measurement rate of water consumption in the current irrigation area, the high input equipment and manpower requirements, and the difficulty in accurately measuring the net irrigation water absorbed by crops. Therefore, this paper proposed the method of “field monitoring - remote sensing inversion - a comprehensive analysis of data.” The method of “field monitoring - remote sensing inversion - econometric model construction - comprehensive analysis” was proposed in this paper, which can obtain gross irrigation water utilizing field monitoring, overcome the difficulty of accurate monitoring of net irrigation water using remote sensing, and carried out a comprehensive analysis, to realize the scientific, effective and rapid calculation of effective utilization coefficient of irrigation water. This method was applied to the Meixian District, Guangdong Province, and the research results show that it not only generates reliable measurement data but also alleviates workload. Furthermore, it offers scientific measurement techniques for water use efficiency indicators, facilitating the achievement of “dual control over total volume and intensity.” This paper provides an important technical basis for the rational allocation of water consumption and scientific approval of water use plans and supports the assessment of the effectiveness of water-saving irrigation development and the reasonable evaluation of the water-saving potential of farmland irrigation, thus providing a basis for local government departments at all levels to make planning, scientific decision-making, and macro-management.
Identifying faults in UHVDC transmission systems using DAE and ensemble learning
Authors: Guo Yiheng , Zhao Qingshen , Liang Dingkang
Published: October 2024

The current fault identification technique for the ultra high voltage direct current transmission system has a low success rate, the process of extracting feature qualities is complex, and it is difficult to identify high resistance grounding. This research provides a defect evaluation method for UHVDC transmission system using Deep Auto Encoder (DAE) and integrated learning. Firstly, the fault voltage signal is feature extracted using DAE, and then, a series of obtained features are feature screened by XGBoost algorithm and combined with an integrated classifier consisting of Multi-Layer Perceptron (MLP), K Nearest Neighbor (KNN), and Random Forest (RF) classifiers to identify the UHVDC faults. Finally, ±800kV UHVDC transmission line models are established in MATLAB/Simulink simulation software to simulate different types of faults. The study’s findings demonstrate that the fault diagnostic method introduced in this research may significantly enhance the poor detection success rate of current fault diagnostics methods and is more resilient to excessive resistance.
Analysis of motion performance and motion mode recognition in filament propulsion
Authors: Sun Weizhen , He Guoyi , Wang Qi
Published: October 2024

In this study, the full free motion of the filament in vortex structures is numerically simulated, and the influence of model parameters and horizontal position on the propulsion efficiency of the filament is investigated. With the “data + physics” approach with the immersed boundary method and Random Forest (RF) method, an RF model is initially employed to screen 189 sets of numerical experiments using a minimal amount of flow field physical data to select experimental groups capable of generating vortex bands. The selected experimental groups are then used to complete numerical experiments, followed by the re-introduction of a minimal amount of data and the use of the RF model to identify the motion modes of the filament. The experimental results indicate that the stretching coefficient of the filament has a negative effect on the thrust coefficient when the filament is in the vortex. The thrust of the filament decreases with increasing horizontal distance. The RF model demonstrates excellent identification capabilities, correctly classifying the vortex street structure with only three sets of data from three test points, achieving a high accuracy rate of 95% in identifying the motion modes of the filament.