bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tensile behavior of square-twist origami inspired mechanical metamaterials with soft joints and chirality applications
Authors: Wang Haoqian , Qu Haibo , Wang Xiaolei , He Yufan , Guo Sheng 
Published: May 2024

Abstract
The performance and behavior of origami-inspired mechanical metamaterials are closely related to their structural design and the joints sub equivalent to the crease, in addition to material selection. Current research on square-twist origami focused on the unidirectional formation between its stable states. However, the complete process of squeezing-folding and stretching-unfolding as well as the mechanical behavior under tensile loading have not been thoroughly studied. In this study, square-twist origami mechanical metamaterials (STOMMs) with soft joints are proposed and investigated. The complete process of typical STOMMs from a flat state to folded stable state by extrusion folding and then returning to a flat state by stretch unfolding is explored using the finite element method. The strain energy and deformation characteristics of STOMMs are revealed at eight special stages during the folding, stable state, and unfolding processes. Additionally, the influence of geometric parameters on strain energy, deformation, and tensile behavior is also investigated. Finally, inspired by origami chirality, combinatorial mechanical metamaterials with self-locking/non-self-locking behavior are proposed and validated for their tensile and self-locking behavior. The studies could provide new content for origami-inspired soft joint mechanical metamaterials in terms of self-locking and load-bearing.
Physics-informed deep operator network for predicting martensite evolution in superelastic shape memory alloys through cyclic tensile tests
Authors: Lenzen Niklas , Altay Okyay 
Published: May 2024

Abstract
Superelastic shape memory alloy (SMA) wires and rods possess unique deformation and energy dissipation capabilities. For the assessment of their stress response, commonly cyclic tensile tests are conducted. An important but subtle parameter in this procedure is the martensite evolution. In scenarios where conducting thermal experiments is impractical, inverse modeling from cyclic tests serves as a viable alternative. However, employing constitutive models in this process presents distinct challenges, such as parameter identification and calibration, or numerical stability issues. To address these challenges, this paper proposes a data-driven method based on a physics-informed deep operator network (DeepONet) to estimate the martensite evolution. Constraint with a stress equation, the network requires only strain–stress data for training and provides stress responses in addition to the martensite evolution. From the training data, the network learns to consider the effects included in the response. The DeepONet can be coupled with experiments to provide online estimates from noisy sensor-based strain inputs, while remaining numerically stable. Moreover, this approach avoids the need for separate parameter identification or calibration. This paper details this method and evaluates its performance through experiments conducted on superelastic SMA wires. Furthermore, as an alternative approach, training using a constitutive model is provided.
Two dimensional simulations to study the relationship between settling velocity and flexibility of a particle
Authors: Panghal Rekha , Ghosh Sudeshna , Sharma Amit 
Published: May 2024

Abstract
In various industrial and real-life scenarios, sedimentation, whether involving flexible fibres, permeable structures, or a combination of both, plays a pivotal role. Its impact spans from influencing paper properties to waste water treatment and microorganism transport dynamics. Understanding sedimentation is crucial for optimizing processes like flocculation, organic matter removal, and particulate material management. Settling velocity, a key metric, is vital in designing instruments and formulating optimization strategies across environmental engineering and sediment transport. Despite extensive research on settling velocity correlations with viscosity, structure density, and permeability, the relationship with structural flexibility remains unexplored. This study employs the Immersed Boundary (IB) method, utilizing a MATLAB code to numerically investigate the correlation between settling velocity and the flexibility of settling structures, addressing a gap in prior research. The results demonstrate a robust correlation between settling velocity and flexibility, supported by high R-squared values (ranging from 0.9979 to 1) for exponential fits across all discussed cases. The R-squared value, a statistical measure assessing model accuracy, reinforces the superiority of the exponential fit in describing the settling velocity-flexibility relationship. To confirm the optimal fit, we conducted fitting attempts with various curve types using MATLAB, encompassing polynomial, Fourier, and smooth spline curves for both impermeable and permeable structures. The exponential curve consistently emerged as the most fitting model in this context.In our recent research, we conducted a sensitivity analysis focusing on the time-step to validate the robustness of our findings. The investigation encompassed both impermeable and permeable scenarios for the structures under study. The time-step was systematically varied across a specified range, revealing a notable outcome: the results demonstrated a consistent independence from the chosen time-step values.
Subtraction of liposome signals in cryo-EM structural determination of protein–liposome complexes
Authors: Li 李 Shouqing 首卿 , Li 李 Ming 明 , Wang 王 Yumei 玉梅 , Li 李 Xueming 雪明 
Published: May 2024

Abstract
Reconstituting membrane proteins in liposomes and determining their structure is a common method for determining membrane protein structures using single-particle cryo-electron microscopy (cryo-EM). However, the strong signal of liposomes under cryo-EM imaging conditions often interferes with the structural determination of the embedded membrane proteins. Here, we propose a liposome signal subtraction method based on single-particle two-dimensional (2D) classification average images, aimed at enhancing the reconstruction resolution of membrane proteins. We analyzed the signal distribution characteristics of liposomes and proteins within the 2D classification average images of protein–liposome complexes in the frequency domain. Based on this analysis, we designed a method to subtract the liposome signals from the original particle images. After the subtraction, the accuracy of single-particle three-dimensional (3D) alignment was improved, enhancing the resolution of the final 3D reconstruction. We demonstrated this method using a PIEZO1-proteoliposome dataset by improving the resolution of the PIEZO1 protein.
Relating SI units to the ‘defining constants’
Authors: Blattner Peter , Brown Richard J C 
Published: May 2024

Abstract
This contribution discusses the direct relationship of any SI unit to the defining constants. For many of the SI derived units the relationships to the defining constants are simpler than to the SI base units. Furthermore, some of the relationships directly reflect the fundamental quantum-physical effects that are exploited in the primary realisation of units. It is not the intention of this article to question the status of the seven SI base units and the distinction between the SI base units and the SI derived units, which have evolved historically and persist for pedagogical reasons, but instead to provide an alternative view of the SI. This alternative view also allows a broader and more modern presentation of metrology in general and demonstrates that, in respect of the ability to be directly realised from the defining constants, there is little practical difference between the SI base units and SI derived units.
Self-supervised motor imagery EEG recognition model based on 1-D MTCNN-LSTM network
Authors: Cunlin Hu , Ye Ye , Nenggang Xie 
Published: May 2024

Abstract

Objective. Aiming for the research on the brain–computer interface (BCI), it is crucial to design a MI-EEG recognition model, possessing a high classification accuracy and strong generalization ability, and not relying on a large number of labeled training samples. Approach. In this paper, we propose a self-supervised MI-EEG recognition method based on self-supervised learning with one-dimensional multi-task convolutional neural networks and long short-term memory (1-D MTCNN-LSTM). The model is divided into two stages: signal transform identification stage and pattern recognition stage. In the signal transform recognition phase, the signal transform dataset is recognized by the upstream 1-D MTCNN-LSTM network model. Subsequently, the backbone network from the signal transform identification phase is transferred to the pattern recognition phase. Then, it is fine-tuned using a trace amount of labeled data to finally obtain the motion recognition model. Main results. The upstream stage of this study achieves more than 95% recognition accuracy for EEG signal transforms, up to 100%. For MI-EEG pattern recognition, the model obtained recognition accuracies of 82.04% and 87.14% with F1 scores of 0.7856 and 0.839 on the datasets of BCIC-IV-2b and BCIC-IV-2a. Significance. The improved accuracy proves the superiority of the proposed method. It is prospected to be a method for accurate classification of MI-EEG in the BCI system.
Trajectory planning and simulation of upper limb rehabilitation robot based on NSGA2
Authors: Yao Hengwen , Duan Fuhai , Wang Xiaobin 
Published: May 2024

Abstract
In order to increase the stability and comfort of hemiplegic rehabilitation training, this paper integrates B-spline curves with a non-dominated sorting genetic algorithm (NSGA2) for trajectory planning of a 5-DOF upper limb exoskeleton rehabilitation robot, the structural characteristics of the robot are analyzed. Subsequently, the forward kinematics equation is derived by the D-H method, and its correctness is verified by Adams simulation. Subsequently, the robot workspace is calculated, and the outcomes show that it satisfies the patient’s demand for activity. Finally, the trajectory curve is constructed using the 5th-order B-splines. Under kinematic constraints, the NAGA2 is used to discover the ideal time interval sequence for time, impact and energy, and then complete the trajectory planning. The simulation findings demonstrate the suggested trajectory planning method produces continuous, smooth, and high-performance motion trajectories, providing good rehabilitation training for patients.
Rolling bearing fault diagnosis based on multi-source data fusion
Authors: Li Haomiao 
Published: May 2024

Abstract
In this paper, a fault diagnosis method is proposed based on multi-source data fusion to address the inaccurate results caused by single evidence used for decision-making. First, empirical mode decomposition is performed using sensor data to extract fault features, and a fault feature matrix and a diagnostic matrix are established. Then the deviation vector is defined to obtain the difference between the diagnostic sample and the fault sample, and then the basic probability assignment is obtained for each diagnostic sample. Finally, the Dempster combination rule is used for fusion. The effectiveness and accuracy of this method in fault diagnosis of rolling bearings have been verified through examples of rolling bearings.
Research on linear/nonlinear active disturbance rejection switching control of PMSM speed servo system
Authors: Wang Yilin , Liu Huibo 
Published: May 2024

Abstract
An improved linear/nonlinear active disturbance rejection switching control strategy is proposed to enhance the dynamic response and disturbance suppression capabilities of the permanent magnet synchronous motor (PMSM) speed servo system. Firstly, facilitated by a tracking differentiator, rapid setpoint tracking is achieved without speed overshoot, effectively addressing the inherent conflict between fast system response and overshooting. Secondly, weight factors are introduced into the control law, and a novel switching criterion based on the step function is designed, enabling the system to smoothly transition between operating modes in the presence of disturbances with varying amplitudes. This facilitates accurate estimation and swift compensation for disturbances, thereby enhancing control precision and robustness. Additionally, a frequency domain analysis of the extended state observer is conducted, leading to the formulation of a parameter tuning scheme for the controller. Lastly, simulation tests validate the feasibility and effectiveness of this strategy as a PMSM speed controller. The system exhibits superior dynamic tracking and disturbance suppression performance over a wide speed range.
Design of class f reconfigurable power amplifiers
Authors: Liu Wenjin , Dong Haojie , Nan Jingchang 
Published: May 2024

Abstract
With the rapid development of mobile communication technology, RF amplifier requirements becoming higher, miniaturization, high efficiency and multi-band have gradually become a research hotspot. Based on these hot research directions, this paper designs a dual-band reconfigurable power amplifier. The input of the amplifier adopts a stepped impedance matching network, which has a good matching effect in the 1.6 - 2.8 GHz band. The output is switched by a single-knife double-throw switch to the corresponding band output matching network to achieve the fast switching of different frequency bands. The RF amplifier tube is designed by using Cree’s GaN chip CGH40010F, which has an additional power efficiency of more than 60% in the frequency range of 1.7 - 1.9 GHz and 2.5 - 2.7 GHz bands, a gain of about 12 - 14 dB and a saturated output power of more than 40 dBm. This design has the features of high efficiency, high gain, miniaturization and multi-band, which is applicable to the mobile communication system.
A novel method for cycle slip detection and restoration of BDS carrier phase
Authors: Yuan Zhenguo 
Published: May 2024

Abstract
The chief purpose of this present study is to develop a new approach to cycle slip detection and restoration of the BeiDou Navigation Satellite System (BDS) carrier phase. Based on the RAIM algorithm in the application of aviation safety, we extend the application to ensure the precision of the carrier phase. To stand-alone receivers of a low-cost single frequency, carrier phase data is made different between adjacent epochs. Then least-square residuals were to design a RAIM scheme with differential carrier phase data to find out the epoch with cycle slip, and finally repair cycle slip by Chebyshev polynomial. Results indicate that the approach can detect cycle slip effectively and both big cycle slip and small cycle slip could be repaired.
Calculation of spontaneous radiation during channeling of relativistic positrons in non-chiral nanotubes using a quadratic approximation
Authors: Maksyuta N.V. , Vysotskii V.I. , Maksyuta D.N. , Efimenko S.V. , Slinchenko Yu.A. 
Published: May 2024

Abstract
The work investigates the conditions for the possibility of using the quadratic
approximation U(ρ) = αρ2 for the interaction potentials of channeled
positrons with the inner walls of non-chiral carbon nanotubes of types (n, 0) and
(n, n). In particular, (8, 0), (10, 0), (12, 0) and (8, 8), (10, 10), (12, 12)
nanotubes were selected. In this case, when calculating the single-particle potential of the
carbon atom, only the contribution of valence electrons was taken into account. As a result of
this approximation, the parameters α were determined for all the nanotubes
studied. Using wave functions and the corresponding quantum levels of transverse energy obtained
by solving the Schrödinger equation, the probabilities of occupation of these levels were
calculated for positron beams with zero angular dispersion moving along the axes of
nanotubes. Based on this information, values of the longitudinal energy of positrons for which the
quadratic approximation is applicable were determined for all the studied nanotubes. Spectral
distributions of spontaneous radiation were calculated in the dipole approximation for
non-dispersive relativistic positron beams, both within the framework of quantum-mechanical and
classical approaches.
CMS ECAL VFE design, production and testing
Authors: Lustermann W. , Abadjiev D. , Dissertori G. , Dejardin M. , Gadek T. , Martin L.T. , Stachon K. ,   the CMS collaboration
Published: May 2024

Abstract
Maintaining the required performance of the CMS electromagnetic calorimeter (ECAL) barrel at the High-Luminosity Large Hadron Collider (HL-LHC) requires the replacement of the entire on-detector electronics. 12240 new very front end (VFE) cards will amplify and digitize the signals of
61200
lead-tungstate crystals instrumented with avalanche photodiodes. The VFE cards host five channels of CATIA pre-amplifier ASICs followed by LiTE-DTU ASICs, which digitize signals with 160 MS/s and 12bit resolution. We present the strategy and infrastructure developed for achieving the required reliability of less than 0.5% failing channels over the expected lifetime of 20 years. This includes the choice of standards, design for reliability and manufacturing, as well as factory acceptance tests, reception testing, environmental stress screening and calibration of the VFE cards.
Phenomenology and the Norms of Perception
Authors: Doyon Maxime 
Published: May 2024

Abstract
In the philosophical literature, it is customary to think of perception as being assessable with respect to epistemic norms. For example, the whole discussion around disjunctivism, which is now often considered to be the dominant, if not the default, position in philosophy of perception, is framed and motivated by epistemological concerns about truth and falsity. This book argues that perception is normative in another, more fundamental, sense. Perception is governed by norms that I call perceptual, that is, immanent to its own structure. This does not mean that perceptual norms are cut off from external facts; rather, it means that they are constitutive moments of our experience of these facts. Perceptual norms are constitutive or enabling norms in that they establish what perception is. To articulate this, the book draws on the repertoire of the phenomenological tradition, in the work of Edmund Husserl and Maurice Merleau-Ponty in particular. For both phenomenologists, perception obtains when it unfolds concordantly or coherently, and when the perceptual progression corresponds to one’s goal or interest, perception can also be said to be optimal. From the phenomenological point of view, concordance and optimality are the basic perceptual norms governing perceptual experience, and the book clarifies their meaning and addresses the philosophical consequences that follow. The first two chapters outline Husserl’s and Merleau-Ponty’s account of perception, illusions, and hallucinations. The following five chapters put the author’s theory to test in the broader philosophical landscape by engaging in five ongoing debates in philosophy of mind and perception.
Perceptual Normativity in Merleau-Ponty
Authors: Doyon Maxime 
Published: May 2024

Abstract
Despite Merleau-Ponty’s well-known reservations about some aspects of Husserlian phenomenology, this chapter shows that the analyses of perceptual experiences carried out in the Phenomenology of Perception accord with Husserl’s on a fundamental respect: like for Husserl, Merleau-Ponty conceives of perception, illusions, and hallucinations both in intentional and normative terms. After having shown the role of the norms of concordance (Section 2.1) and optimality (Section 2.2) in Merleau-Ponty’s account of perceptions, the chapter provides a detailed analysis of his phenomenological conception of illusion (Section 2.3) and hallucination (Section 2.4) in turn, exposing how Merleau-Ponty defines both types of experiences in terms of the specific ways they break with the norms of regular perceptual experiencing. Throughout, the chapter insists more on the commonalities than on the differences between Husserl’s and Merleau-Ponty’s accounts of perceptual experience and demonstrates how both phenomenologists deal with the threat of scepticism (Section 2.5).
Perceiving Together
Authors: Doyon Maxime 
Published: May 2024

Abstract
Over the last three decades the phenomenon of ‘sharing’ has been the object of many discussions in the field of collective intentionality or social ontology, whose discussions typically revolve around the paradigmatic cases of ‘shared actions’, which include, without being limited to, shared perceptions. By developing an account of shared perceptual responsiveness, this chapter specifies the correct way to satisfy the required conditions of shared perception: a perceptual We emerges in the way individuals jointly respond to commonly perceived cues. Throughout, the chapter stresses the fundamental role of embodied agency and pre-reflectively experienced time, the two pillars upon which shared perceptual responses rest. It is argued that co-experiencers typically display their normative sensitivity to shared perceptual situations by acting in certain typical ways (and not others), which is in turn only possible if they share a temporal horizon. Ultimately, shared perceptual responsiveness rests on a shared sense of time.
The Never-Ending Problem of Demarcation: Addressing the Air/Space Boundary Issue in International and Domestic Law
Authors: Newman Christopher J 
Published: May 2024

Abstract
This chapter examines the various legal approaches to demarcation of airspace and outer space. It will look at the issues in identifying the legal boundary at which sovereign air law ceases and an object or individual enters outer space. This discussion critically re-evaluates two approaches to identifying the boundary. The first of these, the spatialist approach, ascribes a specific altitude, such as the Kármán line. The second, the functionalist approach, takes a holistic view of the function and purpose of a spacecraft to determine the applicable regime. Neither of these propositions is without their difficulties and this chapter will look at the challenges posed by the development of launch solutions throughout the twenty-first century and the issues that these advances in technology present. It is contended that the problem of demarcation will need a legally certain position as human space activity develops if a conflict is to be avoided.
The Contribution of the United Nations to the Development of International Space Law
Authors: Freeland Steven , Martin Anne-Sophie 
Published: May 2024

Abstract
The international legal framework for outer space activities has largely been developed through the consensus process within the Vienna-based United Nations Committee on the Peaceful Uses of Outer Space (UNCOPUOS), the primary multilateral fora dealing with the exploration and use of outer space for peaceful purposes. The UNCOPUOS has made a remarkable contribution to the development of the international regulatory framework for space through the adoption of five binding Treaties, five sets of United Nations General Assembly (UNGA) Principles, as well as an array of other ‘soft law’ instruments. This chapter examines the development of this international regulatory framework within the UNCOPUOS, and the major role it continues to play in promoting international cooperation in the field of space exploration. Lastly, it discusses the evolution of this framework within the security perspective of space activities addressed by the First Committee of the UNGA and in the Conference on Disarmament (CD).