bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of plasticity on the magnetic-field-induced bending deformation in a magneto-active elastomer with superparamagnetic nanoparticles
Authors: Kalita V. M. , Dzhezherya Yu I. , Cherepov S. V. , Skirta Yu B. , Kyryliuk A. V. , Reshetniak S. O. , Bodnaruk A. V. , Ryabchenko S. M. 
Published: January 2024

The influence of residual plastic deformation on the bending deformation of a magnetoactive elastomer (MAE) beam with non-coercive superparamagnetic manganite (La0.6Ag0.2Mn1.2O3) nanoparticles induced by a transverse uniform magnetic field has been studied. It was found that the MAE bending induced by the magnetic field switching-on/switching-off is mainly cyclic elastic. Plastic deformation leads to the emergence of residual bending and hysteresis in the field dependence of the bending. It was shown that the residual bending that appears after the first magnetic field switch-on eliminates the uncertainty of the bending direction at the next magnetization. Due to the residual plastic deformation, the bending direction of the superparamagnetic MAE with nanoparticles does not change when the direction of the applied magnetic field is inverted, in contrast to the MAE with microparticles where the uncertainty of the bending direction is eliminated due to the residual magnetization of weakly coercive ferromagnetic microparticles; therefore, the bending direction changes its sign with magnetic field reversion. In the low fields, the bending value for the MAEs with superparamagnetic particles is proportional to the square of the magnetic field strength. Model estimates on the residual deformation influence on the beam bending at beam magnetization reversal were obtained.
Development of the Langmuir probe under q-distribution for NCST
Authors: Xiao Donghua , Chen Xiaochang , Liu Sanqiu , Chen Hui , Xiong Yuzhen 
Published: January 2024

The Langmuir probe is one of the important diagnostic methods for measuring the edge plasma parameters of tokamak. A quadruple Langmuir probe (QLP) system was designed and built on the NanChang Spherical tokamak (NCST). The nonextensive single Langmuir probe (NSLP) theory [Qiu et al., Phys. Rev. E 101, 043206 (2020)] is extended to the nonextensive QLP (NQLP) theory, and then the electron temperature and electron number density of the edge plasma in NCST are obtained. The results show that the differences between the edge plasma parameters (electron temperature and number density) under the nonextensive statistics and those under the Maxwellian distribution are more than 50%, which indicates that the nonextensive parameters have an important influence on the actual measurement of QLP.
Magnetization process of antiferromagnetic quantum spin chains with the biquadratic exchange interaction
Authors: Sakai Tôru 
Published: January 2024

The magnetization processes of the S = 3/2 and S = 2 antiferromagnetic chains with the biquadratic interaction are investigated using the numerical diagonalization of the finite-size cluster. It is found that the system does not exhibit the spin nematic phase, which was predicted to occur for the S = 1 antiferromagnetic chain. Instead, the present analysis reveals that the quantum spin triatic and quatic liquid phases appear below the saturation magnetization for sufficiently large negative biquadratic interaction, for S = 3/2 and S = 2 chains, respectively. In addition it is also found that the magnetization jump up to the saturation magnetization appears for the small negative biquadratic interaction. The phase diagrams with respect to the negative biquadratic interaction and the magnetization are presented for the S = 3/2 and S = 2 antiferromagnetic chains.
Enhanced heating efficiency for hollow Fe3O4 spherical submicron particles
Authors: Tsuji Takahiro , Kobayash Satoru 
Published: January 2024

We have investigated ac hysteresis loops of hollow Fe3O4 submicron particles with variable particle size of d = 100−696 nm by micromagnetic simulations to investigate the possible application to magnetic hyperthermia. For the hollow particle with the inner/outer diameter ratio of γ = 0.5, the hysteresis loss increases with increasing d and maximizes at d ∼ 300 nm, whereas the hysteresis loss generally increases with γ, but its behavior strongly depends on d. A specific absorption rate, calculated from the loop area at the field frequency of 500 kHz, attains 560 W/g for d = 296 nm and γ = 0.5, which is comparable to that for conventional superparamagnetic nanoparticles. This enhanced specific absorption ratio for the hollow particles can be explained by strong irreversibility between vortex states with different orientation of the vortex core, i.e. along the magnetic field and ⟨111⟩ easy axes.
On the origin of systematic errors in VSM torque curves
Authors: Sapkota Arjun , Rodriguez Leo , C. Binod D. , Dieckow Kolton , Howlader Chandan Q. , Geerts Wilhelmus J. , Tate Jitendra 
Published: January 2024

Magnetic anisotropy (MA) is a basic and crucial magnetic property which describes how the magnetic properties change with field angle in a magnetic composite. Torque measurements are normally used to measure a sample’s anisotropy constant and can be determined directly using a torque magnetometer (TM) or indirectly using a vibrating sample magnetometer (VSM). Most TM only operate at room temperature. However, a biaxial VSM allows straightforward torque measurements at varying temperatures. VSM torque curves comprise a 2θ background caused by small misalignments of the sample on the sample rod, and/or a non-azimuthal symmetric sample shape. These errors originate from the position dependence of the pickup coil sensitivity matrix. Here, the magnetic torque of a strontium ferrite/PA-12 3D printed samples was explored using biaxial VSM and compared to measurements done with a true torque magnetometer. Torque curves were taken from 16-22kOe every 2kOe on a 4.8 mm wire and a 1.23 mm dot sample using a MicroSense EZ9 VSM. Fourier analysis was used to determine the second harmonics from each torque curve. The biaxial torque curves of the wire samples have a much larger torque amplitude which is mainly due to the crosstalk of the y-coil set. Crosstalk originates from the non-azimuthal symmetric shape of the sample and due to the wobble originating from small sample misalignments on the sample rod. Background can be minimized by using samples with near cylindrical symmetry and using a microscope when mounting the sample on the sample rod.
Plasmon-enhanced multi-photon excited photoluminescence of Au, Ag, and Pt nanoclusters
Authors: Bornacelli J , Torres-Torres C , Crespo-Sosa A , Reyes-Esqueda J A , Oliver A 
Published: January 2024

Abstract
In this work, we have studied the multi-photon excited photoluminescence from metal nanoclusters (NCs) of Au, Ag and Pt embedded in Al2O3 matrix by ion implantation. The thermal annealing process allows to obtain a system composed of larger plasmonic metal nanoparticles (NPs) surrounded by photoluminescent ultra-small metal NCs. By exciting at 1064 nm, visible emission, ranging from 450 to 800 nm, was detected. The second and fourth-order nature of the multiphoton process was verified in a power-dependent study measured for each sample below the damage threshold. Experiments show that Au and Ag NCs exhibit a four-fold enhanced multiphoton excited photoluminescence with respect to that observed for Pt NCs, which can be explained as a result of a plasmon-mediated near-field process that is of less intensity for Pt NPs. These findings provide new opportunities to combine plasmonic nanoparticles and photoluminescent nanoclusters inside a robust inorganic matrix to improve their optical properties. Plasmon-enhanced multiphoton excited photoluminescence from metal nanoclusters may find potential application as ultrasmall fluorophores in multiphoton sensing, and in the development of solar cells with highly efficient energy conversion modules.
Glimm’s method and density of wild data for the Euler system of gas dynamics
*
Authors: Chiodaroli Elisabetta , Feireisl Eduard 
Published: January 2024

Abstract
We adapt Glimm’s approximation method to the framework of convex integration to show density of wild data for the (complete) Euler system of gas dynamics. The desired infinite family of entropy admissible solutions emanating from the same initial data is obtained via convex integration of suitable Riemann problems pasted with local smooth solutions. In addition, the wild data belong to BV class.
Respiratory motion modelling for MR-guided lung cancer radiotherapy: model development and geometric accuracy evaluation
Authors: Eiben Björn , Bertholet Jenny , Tran Elena H , Wetscherek Andreas , Shiarli Anna-Maria , Nill Simeon , Oelfke Uwe , McClelland Jamie R 
Published: January 2024

Abstract

Objective. Respiratory motion of lung tumours and adjacent structures is challenging for radiotherapy. Online MR-imaging cannot currently provide real-time volumetric information of the moving patient anatomy, therefore limiting precise dose delivery, delivered dose reconstruction, and downstream adaptation methods. Approach. We tailor a respiratory motion modelling framework towards an MR-Linac workflow to estimate the time-resolved 4D motion from real-time data. We develop a multi-slice acquisition scheme which acquires thick, overlapping 2D motion-slices in different locations and orientations, interleaved with 2D surrogate-slices from a fixed location. The framework fits a motion model directly to the input data without the need for sorting or binning to account for inter- and intra-cycle variation of the breathing motion. The framework alternates between model fitting and motion-compensated super-resolution image reconstruction to recover a high-quality motion-free image and a motion model. The fitted model can then estimate the 4D motion from 2D surrogate-slices. The framework is applied to four simulated anthropomorphic datasets and evaluated against known ground truth anatomy and motion. Clinical applicability is demonstrated by applying our framework to eight datasets acquired on an MR-Linac from four lung cancer patients. Main results. The framework accurately reconstructs high-quality motion-compensated 3D images with 2 mm3 isotropic voxels. For the simulated case with the largest target motion, the motion model achieved a mean deformation field error of 1.13 mm. For the patient cases residual error registrations estimate the model error to be 1.07 mm (1.64 mm), 0.91 mm (1.32 mm), and 0.88 mm (1.33 mm) in superior-inferior, anterior-posterior, and left-right directions respectively for the building (application) data. Significance. The motion modelling framework estimates the patient motion with high accuracy and accurately reconstructs the anatomy. The image acquisition scheme can be flexibly integrated into an MR-Linac workflow whilst maintaining the capability of online motion-management strategies based on cine imaging such as target tracking and/or gating.
Development of a Monte Carlo-based scatter correction method for total-body PET using the uEXPLORER PET/CT scanner
Authors: Bayerlein Reimund , Spencer Benjamin A , Leung Edwin K , Omidvari Negar , Abdelhafez Yasser G , Wang Qian , Nardo Lorenzo , Cherry Simon R , Badawi Ramsey D 
Published: January 2024

Abstract

Objective. This study presents and evaluates a robust Monte Carlo-based scatter correction (SC) method for long axial field of view (FOV) and total-body positron emission tomography (PET) using the uEXPLORER total-body PET/CT scanner. Approach. Our algorithm utilizes the Monte Carlo (MC) tool SimSET to compute SC factors in between individual image reconstruction iterations within our in-house list-mode and time-of-flight-based image reconstruction framework. We also introduced a unique scatter scaling technique at the detector block-level for optimal estimation of the scatter contribution in each line of response. First image evaluations were derived from phantom data spanning the entire axial FOV along with image data from a human subject with a large body mass index. Data was evaluated based on qualitative inspections, and contrast recovery, background variability, residual scatter removal from cold regions, biases and axial uniformity were quantified and compared to non-scatter-corrected images. Main results. All reconstructed images demonstrated qualitative and quantitative improvements compared to non-scatter-corrected images: contrast recovery coefficients improved by up to 17.2% and background variability was reduced by up to 34.3%, and the residual lung error was between 1.26% and 2.08%. Low biases throughout the axial FOV indicate high quantitative accuracy and axial uniformity of the corrections. Up to 99% of residual activity in cold areas in the human subject was removed, and the reliability of the method was demonstrated in challenging body regions like in the proximity of a highly attenuating knee prosthesis. Significance. The MC SC method employed was demonstrated to be accurate and robust in TB-PET. The results of this study can serve as a benchmark for optimizing the quantitative performance of future SC techniques.
The influence of cardiac arrhythmias on the detection of heartbeats in the photoplethysmogram: benchmarking open-source algorithms
Authors: Jeanningros Loïc , Le Bloa Mathieu , Teres Cheryl , Herrera Siklody Claudia , Porretta Alessandra , Pascale Patrizio , Luca Adrian , Solana Muñoz Jorge , Domenichini Giulia , Meister Théo A , Soria Maldonado Rodrigo , Tanner Hildegard , Vesin Jean-Marc , Thiran Jean-Philippe , Lemay Mathieu , Rexhaj Emrush , Pruvot Etienne , Braun Fabian 
Published: January 2024

Abstract

Objective. Cardiac arrhythmias are a leading cause of mortality worldwide. Wearable devices based on photoplethysmography give the opportunity to screen large populations, hence allowing for an earlier detection of pathological rhythms that might reduce the risks of complications and medical costs. While most of beat detection algorithms have been evaluated on normal sinus rhythm or atrial fibrillation recordings, the performance of these algorithms in patients with other cardiac arrhythmias, such as ventricular tachycardia or bigeminy, remain unknown to date. Approach. The PPG-beats open-source framework, developed by Charlton and colleagues, evaluates the performance of the beat detectors named QPPG, MSPTD and ABD among others. We applied the PPG-beats framework on two newly acquired datasets, one containing seven different types of cardiac arrhythmia in hospital settings, and another dataset including two cardiac arrhythmias in ambulatory settings. Main Results. In a clinical setting, the QPPG beat detector performed best on atrial fibrillation (with a median F
1 score of 94.4%), atrial flutter (95.2%), atrial tachycardia (87.0%), sinus rhythm (97.7%), ventricular tachycardia (83.9%) and was ranked 2nd for bigeminy (75.7%) behind ABD detector (76.1%). In an ambulatory setting, the MSPTD beat detector performed best on normal sinus rhythm (94.6%), and the QPPG detector on atrial fibrillation (91.6%) and bigeminy (80.0%). Significance. Overall, the PPG beat detectors QPPG, MSPTD and ABD consistently achieved higher performances than other detectors. However, the detection of beats from wrist-PPG signals is compromised in presence of bigeminy or ventricular tachycardia.
An interpretable shapelets-based method for myocardial infarction detection using dynamic learning and deep learning
Authors: Qu Jierui , Sun Qinghua , Wu Weiming , Zhang Fukai , Liang Chunmiao , Chen Yuguo , Wang Cong 
Published: January 2024

Abstract

Objective. Myocardial infarction (MI) is a prevalent cardiovascular disease that contributes to global mortality rates. Timely diagnosis and treatment of MI are crucial in reducing its fatality rate. Currently, electrocardiography (ECG) serves as the primary tool for clinical diagnosis. However, detecting MI accurately through ECG remains challenging due to the complex and subtle pathological ECG changes it causes. To enhance the accuracy of ECG in detecting MI, a more thorough exploration of ECG signals is necessary to extract significant features. Approach. In this paper, we propose an interpretable shapelet-based approach for MI detection using dynamic learning and deep learning. Firstly, the intrinsic dynamics of ECG signals are learned through dynamic learning. Then, a deep neural network is utilized to extract and select shapelets from ECG dynamics, which can capture locally specific ECG changes, and serve as discriminative features for identifying MI patients. Finally, the ensemble model for MI detection is built by integrating shapelets of multi-dimensional ECG dynamic signals. Main results. The performance of the proposed method is evaluated on the public PTB dataset with accuracy, sensitivity, and specificity of 94.11%, 94.97%, and 90.98%. Significance. The shapelets obtained in this study exhibit significant morphological differences between MI and healthy subjects.
Electrostatic-driven soft air pump with segmented electrodes
Authors: Zhao Jindong , Xu Ming , Zhang Yongfa , Yu Tang , Sun Hualiang 
Published: January 2024

Abstract
Pneumatic soft robots have become a popular research area for future robots because of their lightweight, high efficiency, non-pollution, and high reliability. However, the pneumatic pump, which is the ‘heart’ of these robots, is large in size, heavy in weight, noisy in operation, and must be separated from the robot body, which seriously affects the portability and autonomy of the robot. Portable soft pumps fabricated using smart materials provide a viable solution to the above challenges. We present a segmented electrode pump (SEP) driven by electrostatic forces, which combines the advantages of an electro-pneumatic pump (EPP) and an enhanced electrode structure. Compared with the EPP, the developed SEP showed improved characteristics in terms of higher specific flow rate output (1.67 ml s∙g−1), higher specific pressure output (0.483 kPa g−1) and lower power consumption (24 mW). The proposed SEP is expected to provide new solutions to the challenges of embedding air sources and facilitating air supply flexibility, and opens up new opportunities for fully flexible robots.
Quantum imaging beyond the standard-quantum limit and phase distillation
Authors: Schaffrath Simon , Derr Daniel , Gräfe Markus , Giese Enno 
Published: January 2024

Abstract
Quantum sensing using non-linear interferometers (NLIs) offers the possibility of bicolour imaging, using light that never interacted with the object of interest, and provides a way to achieve phase supersensitivity, i.e. a Heisenberg-type scaling of the phase uncertainty. Such a scaling behaviour is extremely susceptible to noise and only arises at specific phases that define the optimal working point (WP) of the device. While phase-shifting algorithms are to some degree robust against the deleterious effects induced by noise they extract an image by tuning the interferometer phase over a broad range, implying an operation beyond the WP. In our theoretical study, we investigate both the spontaneous and the high-gain regime of operation of an NLI. In fact, in the spontaneous regime using a distillation technique and operating at the WP leads to a qualitatively similar behaviour. In the high-gain regime, however, typical distillation techniques inherently forbid a scaling better than the standard-quantum limit, as a consequence of the photon statistics of squeezed vacuum. In contrast, an operation at the WP still may lead to a sensitivity below shot noise, even in the presence of noise. Therefore, this procedure opens the perspective of bicolour imaging with a better than shot-noise phase uncertainty by working in the vicinity of the WP. Our results transfer quantum imaging distillation in a noisy environment to the high-gain regime with the ultimate goal of harnessing its full potential by combining bicolour imaging and phase supersensitivity.
Reflectionless pseudospin-1 Dirac systems via Darboux transformation and flat band solutions
Authors: Jakubský V , Zelaya K 
Published: January 2024

Abstract
This manuscript explores the Darboux transformation employed in the construction of exactly solvable models for pseudospin-one particles described by the Dirac-type equation. We focus on the settings where a flat band of zero energy is present in the spectrum of the initial system. Using the flat band state as one of the seed solutions substantially improves the applicability of the Darboux transformation, for it becomes necessary to ensure the Hermiticy of the new Hamiltonians. This is illustrated explicitly in four examples, where we show that the new Hamiltonians can describe quasi-particles in Lieb lattice with inhomogeneous hopping amplitudes.
Automatic transformation of polarization state of light in void medium
Authors: Yang Jianhe , Tao Shaohua 
Published: January 2024

Abstract
Customized polarization state of light plays a pivotal role in numerous scientific domains. Under normal circumstances, light always maintains its polarization state during transmission in void medium or the free space. However, in this work, we have observed that the polarization state of a light beam can be automatically transformed during the propagation without involving a waveplate or scattering of air. The beam changes polarization states at different distances in the free space propagation. Moreover, while polarization states can be preset at different distances, the intensity and phase of the light beam can also be independently designed. The mechanism behind this phenomenon is due to the superposition and diffraction of the controlled light beams. The phenomenon paves the way for applications of constructing key devices, e.g. optical isolator, and offers a broader range of possibilities for applications such as tunable structured devices, optical diodes, and so on.
An effective hydrodynamic description of marching locusts
Authors: Gorbonos Dan , Oberhauser Felix B , Costello Luke L , Günzel Yannick , Couzin-Fuchs Einat , Koger Benjamin , Couzin Iain D 
Published: January 2024

Abstract
A fundamental question in complex systems is how to relate interactions between individual components (‘microscopic description’) to the global properties of the system (‘macroscopic description’). Furthermore, it is unclear whether such a macroscopic description exists and if such a description can capture large-scale properties. Here, we address the validity of a macroscopic description of a complex biological system using the collective motion of desert locusts as a canonical example. One of the world’s most devastating insect plagues begins when flightless juvenile locusts form ‘marching bands’. These bands display remarkable coordinated motion, moving through semiarid habitats in search of food. We investigated how well macroscopic physical models can describe the flow of locusts within a band. For this, we filmed locusts within marching bands during an outbreak in Kenya and automatically tracked all individuals passing through the camera frame. We first analyzed the spatial topology of nearest neighbors and found individuals to be isotropically distributed. Despite this apparent randomness, a local order was observed in regions of high density in the radial distribution function, akin to an ordered fluid. Furthermore, reconstructing individual locust trajectories revealed a highly aligned movement, consistent with the one-dimensional version of the Toner-Tu equations, a generalization of the Navier–Stokes equations for fluids, used to describe the equivalent macroscopic fluid properties of active particles. Using this effective Toner–Tu equation, which relates the gradient of the pressure to the acceleration, we show that the effective ‘pressure’ of locusts increases as a linear function of density in segments with the highest polarization (for which the one-dimensional approximation is most appropriate). Our study thus demonstrates an effective hydrodynamic description of flow dynamics in plague locust swarms.