bluuebunny/crossref_metadata_2025_split huggingface dataset:
Superconducting resonator parametric amplifiers with intrinsic separation of pump and signal tones
Authors: Zhao Songyuan , Withington S , Thomas C N 
Published: October 2024

Abstract
Superconducting resonator parametric amplifiers achieve ultra-low-noise amplification through the nonlinear kinetic inductance of thin-film superconductors. One of the main challenges to the operation of these devices is the separation of the strong pump tone from the signal tone after amplification has been achieved. In this paper, we propose and experimentally demonstrate a pump separation method based on operating a half-wave superconducting resonator amplifier behind a cryogenic circulator. Our pump separation scheme does not involve post-amplification interference, and thereby avoids the delicate phase matching of two different pump paths. We demonstrate the scheme using two-port half-wave resonator amplifiers based on superconducting NbN thin-films. We present measurements of gain profiles and degrees of pump separation for amplifiers having different coupling quality factors. On an amplifier having a coupling quality factor of ∼2000, we measured a peak signal gain of

15

dB

whilst achieving pump separation of

12

dB

. The amplifier was stable for continuous measurements, and the gain drift was measured to be

0.15

dB

over an hour. The same amplifier was operated at

3.2

K

and achieved a peak signal gain of

11

dB

whilst having a pump separation factor of

10.5

dB

. The pump separation scheme, and these promising results, will advance the development of superconducting resonator amplifiers as an important technology in quantum sensing.
Spatio-temporal reconstruction of droplet impingement dynamics by means of color-coded glare points and deep learning
Authors: Dreisbach Maximilian , Kriegseis Jochen , Stroh Alexander 
Published: October 2024

Abstract
The present work introduces a deep learning approach for the three-dimensional reconstruction of the spatio-temporal dynamics of the gas–liquid interface on the basis of monocular images obtained via optical measurement techniques. The method is tested and evaluated at the example of liquid droplets impacting on structured solid substrates. The droplet dynamics are captured through high-speed imaging in an extended shadowgraphy setup with additional glare points from lateral light sources that encode further three-dimensional information of the gas–liquid interface in the images. A neural network is trained for the physically correct reconstruction of the droplet dynamics on a labeled dataset generated by synthetic image rendering on the basis of gas–liquid interface shapes obtained from direct numerical simulation. The employment of synthetic image rendering allows for the efficient generation of training data and circumvents the introduction of errors resulting from the inherent discrepancy of the droplet shapes between experiment and simulation. The accurate reconstruction of the three-dimensional shape of the gas–liquid interface during droplet impingement on the basis of images obtained in the experiment demonstrates the practicality of the presented approach based on neural networks and synthetic training data generation. The introduction of glare points from lateral light sources in the experiments is shown to improve the reconstruction accuracy, which indicates that the neural network learns to leverage the additional three-dimensional information encoded in the images for a more accurate depth estimation. By the successful reconstruction of obscured areas in the input images, it is demonstrated that the neural network has the capability to learn a physically correct interpolation of missing data from the numerical simulation. Furthermore, the physically reasonable reconstruction of unknown gas–liquid interface shapes for drop impact regimes that were not contained in the training dataset indicates that the neural network learned a versatile model of the involved two-phase flow phenomena during droplet impingement.
Local maximum synchrosqueezing adaptive transformation for cross-instantaneous frequencies analysis
Authors: Hou Yating , Zhang Junzhu , Han Xingcheng , Wang Liming , Xu Xudong , Zhang Shuai 
Published: October 2024

Abstract
To overcome the shortcomings of existing time-frequency (TF) analysis (TFA) methods in analyzing signals containing cross-instantaneous frequencies (IFs), this paper proposes an adaptive TFA technique combined with image processing methods based on local maximum synchrosqueezing transform (SST). The core idea of the proposed algorithm is to localize the filtering of signals containing several different IF components using kernel functions containing several different directions, respectively, to achieve energy separation at the crossing frequencies. In turn, the local maximum SST is used to rearrange the TF energy to the true IF ridges of the signal to improve the TF energy concentration. Simulation data demonstrates that the proposed algorithm has higher energy aggregation and better noise immunity, especially for signals with cross-IFs. Applying the proposed method to animal acoustic and radar wave signals of pedestrians can accurately describe the differences in the frequency change patterns and the temporal distribution of energy in the signals, thereby providing a judgment basis for effectively identifying and classifying the signals.
From materials to structures: a holistic examination of achieving linearity in flexible pressure sensors
Authors: Li Pei , Zhang Yong , Li Chunbao , Chen Xian , Gou Xin , Zhou Yong , Yang Jun , Xie Lei 
Published: October 2024

Abstract
As a pivotal category in the realm of electronics skins, flexible pressure sensors have become a focal point due to their diverse applications such as robotics, aerospace industries, and wearable devices. With the growing demands for measurement accuracy, data reliability, and electrical system compatibility, enhancing sensor’s linearity has become increasingly critical. Analysis shows that the nonlinearity of flexible sensors primarily originates from mechanical nonlinearity due to the nolinear deformation of polymers and electrical nonlinearity caused by changes in parameters such as resistance. These nonlinearities can be mitigated through geometric design, material design or combination of both. This work reviews linear design strategies for sensors from the perspectives of structure and materials, covering the following main points: (a) an overview of the fundamental working mechanisms for various sensors; (b) a comprehensive explanation of different linear design strategies and the underlying reasons; (c) a detailed review of existing work employing these strategies and the achieved effects. Additionally, this work delves into diverse applications of linear flexible pressure sensors, spanning robotics, safety, electronic skin, and health monitoring. Finally, existing constraints and future research prospects are outlined to pave the way for the further development of high-performance flexible pressure sensors.
Synergistic applications of quantum dots and magnetic nanomaterials in pathogen detection: a comprehensive review
Authors: Shalileh Farzaneh , Shamani Negin , Golbashy Mohammad , Dadmehr Mehdi , Hosseini Morteza 
Published: October 2024

Abstract
The rapid and accurate detection of pathogens is crucial for effective disease prevention and management in healthcare, food safety, and environmental monitoring. While conventional pathogen detection methods like culture-based techniques and PCR are sensitive and selective, they are often time-consuming, require skilled operators, and are not suitable for point-of-care or on-site testing. To address these limitations, innovative sensor technologies have emerged that leverage the unique properties of nanomaterials. Quantum dots (QDs) and magnetic nanomaterials are two classes of nanomaterials that have shown particular promise for pathogen sensing. This review comprehensively examines the synergistic applications of QDs and magnetic nanomaterials for detecting bacteria, viruses, phages, and parasites.
Flocking analysis and control of a nonlinear collective migration model
Authors: Chen Yipeng , Liu Yicheng , Wang Xiao 
Published: October 2024

Abstract
In this paper, we study a nonlinear collective migration model with the Cucker–Smale type weight, the nonlinear velocity coupling and the distributed network. Finite-time flocking tracking can be achieved by the alignment force gathering agents and the tracking force matching target. A trade-off existing between the two forces is established by the tracking strategy that can be viewed as a control. When the strategy is time-invariant, finite-time flocking tracking would occur for any initial state under the long-range weight, only for partial initial state under the short-range weight. An invariant set of the system is proposed and proved to be an attractive domain of the flocking state. Then two time-varying strategies, the average strategy and the maximum strategy, are designed to overcome the constraint of initial state under the short-range weight. The average strategy has to mobilize all agents simultaneously, but only causes once switch. The maximum strategy only mobilizes the agent with the largest velocity deviation, but produces more switches. Several numerical simulations are provided to observe the effects of the time-invariant and time-varying strategies.
Deep learning-based automatic contour quality assurance for auto-segmented abdominal MR-Linac contours
Authors: Zarenia Mohammad , Zhang Ying , Sarosiek Christina , Conlin Renae , Amjad Asma , Paulson Eric 
Published: October 2024

Abstract

Objective. Deep-learning auto-segmentation (DLAS) aims to streamline contouring in clinical settings. Nevertheless, achieving clinical acceptance of DLAS remains a hurdle in abdominal MRI, hindering the implementation of efficient clinical workflows for MR-guided online adaptive radiotherapy (MRgOART). Integrating automated contour quality assurance (ACQA) with automatic contour correction (ACC) techniques could optimize the performance of ACC by concentrating on inaccurate contours. Furthermore, ACQA can facilitate the contour selection process from various DLAS tools and/or deformable contour propagation from a prior treatment session. Here, we present the performance of novel DL-based 3D ACQA models for evaluating DLAS contours acquired during MRgOART. Approach. The ACQA model, based on a 3D convolutional neural network (CNN), was trained using pancreas and duodenum contours obtained from a research DLAS tool on abdominal MRIs acquired from a 1.5 T MR-Linac. The training dataset contained abdominal MR images, DL contours, and their corresponding quality ratings, from 103 datasets. The quality of DLAS contours was determined using an in-house contour classification tool, which categorizes contours as acceptable or edit-required based on the expected editing effort. The performance of the 3D ACQA model was evaluated using an independent dataset of 34 abdominal MRIs, utilizing confusion matrices for true and predicted classes. Main results. The ACQA predicted ‘acceptable’ and ‘edit-required’ contours at 72.2% (91/126) and 83.6% (726/868) accuracy for pancreas, and at 71.2% (79/111) and 89.6% (772/862) for duodenum contours, respectively. The model successfully identified false positive (extra) and false negative (missing) DLAS contours at 93.75% (15/16) and %99.7 (438/439) accuracy for pancreas, and at 95% (57/60) and 98.9% (91/99) for duodenum, respectively. Significance. We developed 3D-ACQA models capable of quickly evaluating the quality of DLAS pancreas and duodenum contours on abdominal MRI. These models can be integrated into clinical workflow, facilitating efficient and consistent contour evaluation process in MRgOART for abdominal malignancies.
Bremsstrahlung radiation power in fusion plasmas revisited: towards accurate analytical fitting
Authors: Xie Huasheng 
Published: October 2024

Abstract
In fusion plasmas, where electron temperatures

T

e

range from keV to hundreds of keV, bremsstrahlung radiation constitutes a significant energy loss mechanism. While various thermal average fitting formulas exist in the literature, their accuracy is limited, particularly for

T

e

⩽
20

keV with error

>
10
%

. Additionally, non-relativistic fitting formulas become invalid for

T

e

⩾
50

keV. The accurate calculation of bremsstrahlung radiation is important for fusion gain study, especially of advanced fuels fusion. In this work, we develop new but still simple fitting formulas that are valid for electron temperatures ranging from small (

≲
0.1

keV) to extreme relativistic range, with errors of less than 1% even for high atomic number ions (e.g. Z = 30), which could be sufficient for fusion plasma applications. Both electron–ion (e–i) and electron–electron (e–e) bremsstrahlung radiations are considered. Both polynomial fitting with truncated (

t
=

k

B

T

e

/

m

e

c
2

⩽
10

) and one-fit-all formulas are provided. Additionally, we offer fitting formulas for e–i and e–e specifically for electron energies, which could prove useful in non-Maxwellian bremsstrahlung radiation studies.
Enhancement of single-photon level signal detection based on phase sensitive amplification strategy
Authors: Zhang Changchang , Wang Zhaolu , Liu Hongjun , Huang Nan 
Published: October 2024

Abstract
We investigate the ability of phase-sensitive amplification (PSA) to noiselessly amplify the preferred quadrature components of single-photon signals that are limited by phase fluctuations relative to the pump. We present a PSA enhancement strategy that is more realistic for possible experimental realization and is expected to significantly improve the detection of weak signals at the single-photon level and obtain more useful information. Our study shows that with a large PSA gain, proper transmissivity allows both direct and balanced homodyne detections to operate optimally simultaneously, and effectively improves the noise figure degradation owing to the internal losses and non-ideal detection efficiency.
Inelastic resonant scattering of electrons on hydrogen-like ions
Authors: Vasileva D M , Lyashchenko K N , Andreev O Yu , Yu D 
Published: October 2024

Abstract
The inelastic electron scattering is one of the processes that must be understood in detail for the correct interpretation of astrophysical data. We suggest
ab initio
QED treatment of the inelastic scattering of quasi-free electrons on hydrogen-like ions with possible formation and subsequent decay of intermediate autoionizing states. We calculate the doubly differential cross sections for scattering on F8+, Ca19+ and Kr35+ in the range of energies where doubly excited

3
l
3
l
′

states are involved. The energies and widths of these states are presented.
PT-symmetric solitons in networks: a metric graph based approach
Authors: Akramov M , Eshchanov B , Khashimova F , Matrasulov D 
Published: October 2024

Abstract
We propose a model for networks approving PT-symmetric standing solitons. The model is described in terms of the nonlinear Schrödinger equation on metric graphs, with complex PT-symmetric potential given on each bond. Exact soliton solutions of the problem are obtained. The stability analysis of the PT-symmetric standing solitons on the star graph is studied. Extension for other graph topologies is demonstrated by considering a metric tree graph.
Tunable Fano resonances at 2 μm waveband based on a single microring resonator
Authors: Xu Qiang , Li Hongjian , Sun Shibo , Kong Mei , Xu Yameng 
Published: October 2024

Abstract
Development of silicon photonic devices for the 2 μm waveband is urgent since the 2 μm waveband has been considered as a potential communication window for next-generation optical communications. Asymmetric Fano resonances are very promising in the development of devices such as optical switches, sensors, and modulators for the 2 μm waveband. In this paper, a Fano resonance at the 2 μm waveband is theoretically realized by using a silicon-based microring resonator and the thermo-optic effect is employed to tune it. Utilizing this single microring resonator structure instead of the present coupled microring resonator structures, we achieve the Fano resonance with an extinction ratio of 30.5 dB and a slope ratio of 69.3 dB nm−1 at the 2 μm waveband. The metal heater and graphene heater are designed and optimized to achieve the Fano tuning. The thermal-optical tuning efficiencies are 0.46 nm mW−1, 0.61 nm mW−1 and 1 nm mW−1 for the metal heater, the metal heater with air adiabatic slots, and the graphene heater, respectively. This work provides an effective scheme for the formation and tuning of the Fano resonance at the 2 μm waveband, which is conducive to the development of devices and optical communication systems at the 2 μm waveband.
Laser modulation to plateau region and intensity of high-order harmonic generation in monolayer MoTe2
Authors: Ji Zhiqiang , Wu Chenglong , Liu Xiaoyu , Qiao Shiqian , Li Shasha , Bo Xiangyan , Pu Yong , Wu Hong , Li Feng 
Published: October 2024

Abstract
Through solving semiconductor Bloch equations, we theoretically investigated the high-order harmonic generation in monolayer MoTe2 under laser modulation. Adjusting the laser parameters, the plateau region and intensity of harmonics can be effectively regulated. Changing laser wavelength can regulate the width of platform region and the cutoff order of harmonic spectrum. Platform region widens with the increase of laser wavelength. Under different laser wavelengths, the number of photons that need to be absorbed for electron transition varies, which affects the inter-band transition of electrons. Laser vector potential also varies with the wavelength, affecting the intra-band motion of electrons. Laser field strength can significantly change the harmonic intensity. As the laser field strength increases, the harmonic intensity increases and may generate new plateau in the high-energy region. The emergence of new platform is due to the transition of electrons between conduction bands. Our work provides a theoretical exploration for generating high quality harmonics and understanding the micro mechanism of high-order harmonic generation.
Mechanical properties of TPDH-graphene: atomistic aspect
Authors: Peng Qing , Chen Gen , Huang Zeyu , Zhang Yuqiang , Zhang Xiaofan , Chen Xiao-Jia , Hu Zhongwei 
Published: October 2024

Abstract
TPDH-graphene is a new type of two-dimensional carbon material predicted by first-principles calculations to have tetragonal (T), pentagonal (P), decagonal (D) and hexagonal (H) carbon ring structures. First-principles calculations show that this special structure gives it excellent mechanical properties and promising applications in nanoelectronics. In this paper, a comprehensive test of its mechanical properties was carried out using the classical molecular dynamics (MD), mainly exploring the effects of factors such as tensile direction and temperature on its mechanical properties, and exploring the effects of introducing rectangular and circular defects on its mechanical properties. The results show that: TPDH-graphene exhibits significant anisotropy in zigzag and armchair directions, and the material exhibits some tensile toughness in armchair direction; the mechanical properties of the material are weakened at higher temperatures; the adding of defects leads to the reduction of the mechanical properties of the material in different directions to different degrees, and the The tensile toughness in the armchair direction is weakened by the addition of defects.
Spiral shaped highly sensitive rectangular PCF-based cancer cells detector in terahertz regime
Authors: Singh Jaydeep , Khamaru Akash , Kumar Ajeet 
Published: October 2024

Abstract
The increasing fatality rate of cancer in the modern world has become a global concern. To address this issue, early detection of cancer cells in human blood is essential. In this article, a rectangular spiral shaped photonic crystal fiber has been proposed for sensing cancer cells in terahertz regime. The proposed PCF based sensor features a square shaped core surrounded by rectangular air holes of different sizes in a spiral manner. Finite element method based COMSOL Multiphysics software has been used for the design and analysis of the model. The model is sensitive to refractive index variation for the identification of cancer cells. The values of effective refractive index, effective mode area, relative sensitivity, non-linearity, and confinement loss are obtained for MCF-7, MDA-MB-231, Jurkat, HeLa, Basal and PC-12. The PCF based sensor resulted in excellent results of relative sensitivity and Confinement loss as good as 99.377% and 8.59 × 10−12 dBm−1 respectively. Furthermore, the present PCF based sensor model is fabrication feasible, and we hope that it can be utilized at industrial level for biosensing applications in terahertz waveguide regime.
Experimental and numerical investigation of the Doppler-shifted resonance condition for high frequency Alfvén eigenmodes on ASDEX Upgrade
Authors: Ochoukov R. , Bilato R. , Bobkov V. , Faugel H. , Kappatou A. , Schneider P. , Weiland M. , Dreval M. , Sipilä S. , Dendy R. , Johnson T. , Kazakov Ye , McClements K.G. , Moseev D. , Salewski M. ,   ASDEX Upgrade Team,   EUROfusion Tokamak Exploitation Team
Published: October 2024

Abstract
The Doppler-shifted resonance condition for high frequency Alfvénic eigenmodes has been extensively studied on ASDEX Upgrade in the presence of one or a combination of two neutral beam injected (NBI) fast ion populations. In general, only centrally deposited NBI sources drive these modes, while off-axis sources globally stabilize the mode activity. For the case of a single central NBI source, the observed trend is: the highest frequency modes are driven by the lowest energy and lowest pitch angle NBI sources, in line with the expectation from the Doppler-shifted resonance condition. The expected mode frequencies are determined analytically from the two-fluid cold plasma dispersion relation and the most unstable frequency relation, while the mode growth rates are estimated using the fast ion slowing down distribution functions from the ASCOT code. The overall mode frequency trend in a source-to-source variation is tracked, although a systematic overestimate of ∼1 MHz is observed. Possible causes of this overestimate include the finite size of the resonant fast ion drift orbit and non-linear effects such as mode sideband formation. Alternatively, the expected mode frequencies are determined by tracking the growth rate maxima trajectories, this method improves the agreement with the experimentally measured values. A combination of two central mode-driving NBI sources results in the suppression of the mode driven by the lowest energy and the lowest pitch angle NBI source. Computing the analytically expected mode frequency following the method outlined above, again, generally tracks the experimentally observed trend. The mode’s Alfvénic nature allows for a practical application to track the core hydrogen fraction by following the mode frequency changes in response to a varying ion mass density. Such application is demonstrated in a discharge where the average ion mass is varied from ∼2m
p to ∼1.5m
p (where m
p is the proton mass) via a hydrogen puff in a deuterium plasma, in the presence of a strong mode activity. The expected mode frequency changes are computed from the existence of the resonance condition, and the values track the measured results with an offset of ∼0.5 MHz. Overall, the results suggest an intriguing possibility to monitor and control the D-T ion fraction in the core of a fusion reactor in real time using a non-invasive diagnostic.