bluuebunny/crossref_metadata_2025_split huggingface dataset:
Quench detection and early warning based on thermoelastic strain rate for HTS tapes thermally triggered by heat spots
Authors: Chen Jiaxiang , Guan Mingzhi , Tong Yujin , Wang Xingzhe , Zhou Youhe 
Published: December 2022

Abstract
The rapid detection and comprehensive monitoring of quench onset and evolution in high-temperature superconducting (HTS) materials remains immensely challenging because the normal zone propagation velocity in HTS materials is two or three orders of magnitude less than that in low-temperature superconductors. In this study, we experimentally and numerically explore quench events triggered by heat spots in yttrium barium copper oxide HTS tapes to characterize the quench onset and propagation. A multiplexed fiber Bragg grating sensor with multiple gratings was used to perform highly accurate strain measurements. Conventional voltage and temperature measurements were performed synchronously on the HTS tapes. A systematic comparison of these multifield signals during quench onset and development illustrated that the evolution of thermoelastic strain and strain-rate in HTS tapes captures the quench onset and propagation. A distinct feature was exhibited during the quenching of a pre-tensioned HTS tape: the thermoelastic strain initially relaxed but subsequently increased until the strain rate exhibited a significant slope change, which corresponded to the quench onset time. The thermoelastic strain in a nearly unconstrained HTS tape gradually increased until quenching occurred. A prominent characteristic for detecting quench onset in HTS materials have been revealed based on the change in the slope of the thermoelastic strain-rate or the second derivative of the strain remaining nearly constant. For a pre-tensioned HTS tape, the minimization of the thermoelastic strain or the strain-rate becoming zero may be a predictor that preceded the quench by ∼1–2 s, which can be, to a certain extent, regarded as an early warning. Another important and novel result was the experimental demonstration of global strain responses distant from the quench location in the pre-tensioned HTS tape, while the temperature and voltage detection are commonly localized methods. The mechanism behind these thermoelastic strain characteristics was further discussed and simulated from the induced Joule heating throughout the quench event. The measurements and numerical predictions suggested a new paradigm of quench detection based on the thermoelastic strain-rate in HTS materials.
Electronic properties of

α

-Mn-type non-centrosymmetric superconductor Re5.5Ta under hydrostatic pressure
Authors: Mariappan Sathiskumar , Bhoi Dilip , Krishnan Manikandan , Shoko Nagasaki , Vajeeston Ponniah , Arushi  , Kushwaha Roshan Kumar , Singh R P , Sonachalam Arumugam , Uwatoko Yoshiya 
Published: December 2022

Abstract
We have studied the effect of hydrostatic pressure on the superconducting and normal state properties of the non-centrosymmetric superconductor Re5.5Ta using magnetotransport, magnetization, and band structure studies. The superconducting transition temperature (

T

c

) reveals a modest decrease of ∼0.52 K as the external pressure is raised to 8 GPa. We found the Maki parameter,

α

M

>
1
,

both at ambient and high pressures, suggesting the significant role of the Pauli pair breaking effect. Furthermore, the lower critical field was found to decrease with a rate of −1.74 mT GPa−1 as pressure increases to 1.05 GPa. Analysis of the thermally activated flux flow region of

ρ

T
,
H

using the Arrhenius equation reveals the coexistence of single and collective vortex states. Further analysis of the critical current density indicates that the surface and volume pinning centers coexist and remain unaffected with varying pressure. Band structure calculations were performed using density functional theory and reveal a large bulk modulus,

B
0

∼ 289 GPa with

B
0
′

∼ 3.7, suggesting poor compressibility. In addition, we found that the density of states at the Fermi level barely reduces, even at pressures of up to 20 GPa. This is consistent with the experimental observation of robust superconductivity under compression.
Angular momentum and chaos bound of charged particles around Einstein–Euler–Heisenberg AdS black holes
Authors: Chen Deyou , Gao Chuanhong 
Published: December 2022

AbstractIn this paper, we investigate influences of the charge and angular momentum of a particle around a charged Einstein–Euler–Heisenberg AdS black hole on a Lyapunov exponent, and find spatial regions where the chaos bound is violated. Positions of circular orbits are gotten by fixing the charge and angular momentum of the particle, respectively. The positions gradually move away from the event horizon with the increase of the angular momentum when the charge is fixed and with the decrease of the charge when the angular momentum is fixed. For certain values of the charge, angular momentum and Euler–Heisenberg parameter, the spatial regions where the bound is violated are found. When the charge is fixed and the Euler–Heisenberg parameter is large, a small angular momentum causes the violation. Although the angular momentum is small, the corresponding spatial region is not small. An interesting discovery is that the bound is violated by the black hole when the particle’s charge is less than 1 andΛ=0, but this requires the black hole’s charge to be large enough. This violation may be related to the dynamical stability of the black hole. The backreaction of the particle on the background spacetime is not considered in the investigation.
Chiral SQUID-metamaterial waveguide for circuit-QED
Authors: Wang Xin , Lin Ya-Fen , Li Jia-Qi , Liu Wen-Xiao , Li Hong-Rong 
Published: December 2022

Abstract
Superconducting metamaterials, which are designed and fabricated with structured fundamental circuit elements, have motivated recent developments of exploring unconventional quantum phenomena in circuit quantum electrodynamics (circuit-QEDs). We propose a method to engineer 1D Josephson metamaterial as a chiral waveguide by considering a programmed spatiotemporal modulation on its effective impedance. The modulation currents are in the form of travelling waves which phase velocities are much slower than the propagation speed of microwave photons. Due to the Brillouin-scattering process, non-trivial spectrum regimes where photons can propagate unidirectionally emerge. Considering superconducting qubits coupling with this metamaterial waveguide, we analyze both Markovian and non-Markovian quantum dynamics, and find that superconducting qubits can dissipate photons unidirectionally. Moreover, we show that our proposal can be extended a cascaded quantum network with multiple nodes, where chiral photon transport between remote qubits can be realized. Our work might open the possibilities to exploit SQUID metamaterials for realizing unidirectional photon transport in circuit-QED platforms.
Resonance phenomena caused by mixed coupling in tristable systems
Authors: Ning Lijuan , Liu Tianpeng 
Published: December 2022

Abstract
Coupled systems have been widely encountered and have aroused much great interest in improving the response output of the system. Scholars pay more attention to the use of vibration resonance or stochastic resonance to amplify weak signals, but few examine the role of mixed coupling on the system response. The amplifying effect of mixed coupling on signal in tristable oscillators is studied in this paper. The spectral amplification factor, which is used to measure the amplification, shows a resonance peak with the coupling strength. The optimal coupling strength can be found to achieve the maximum output of the system. Moreover, the influence of the depth and position of the potential well on the response output is also analyzed. The results show that the properties of tristable oscillators can change the coupling threshold as well as improve amplification. We speculate that, in addition to the mixed coupling, the intrinsic mechanism of this behavior may be due to the different shapes of the tristable oscillators and their modes of variation. It provides new thoughts for amplifying and detecting weak signals in coupled systems.
Velocity correlations in jackdaw flocks in different ecological contexts
Authors: O’Coin Daniel , Mclvor Guillam E , Thornton Alex , Ouellette Nicholas T , Ling Hangjian 
Published: December 2022

Abstract
Velocity correlation is an important feature for animal groups performing collective motions. Previous studies have mostly focused on the velocity correlation in a single ecological context. It is unclear whether correlation characteristics vary in a single species in different contexts. Here, we studied the velocity correlations in jackdaw flocks in two different contexts: transit flocks where birds travel from one location to another, and mobbing flocks where birds respond to an external stimulus. We found that in both contexts, although the interaction rules are different, the velocity correlations remain scale-free, i.e. the correlation length (the distance over which the velocity of two individuals is similar) increases linearly with the group size. Furthermore, we found that the correlation length is independent of the group density for transit flocks, but increases with increasing group density in mobbing flocks. This result confirms a previous observation that birds obey topological interactions in transit flocks, but switch to metric interactions in mobbing flocks. Finally, in both contexts, the impact of group polarization on correlation length is not significant. Our results suggest that wild animals are always able to respond coherently to perturbations regardless of context.
Pulsed inductive CO2 laser with radio-frequency excitation and influence of the H2 content on the efficiency and lasing temporal characteristics
Authors: Razhev A M , Kargapol `tsev E S , Churkin D S , Trunov I A 
Published: December 2022

Abstract
In 2021, data on the effective pulsed gas discharge inductive CO2 laser with radio-frequency (RF) excitation were published with a pulse output energy of E∼ 1 J (the efficiency η∼ 14.5%) on the gas mixture He:N2:CO2 = 8:2:1. The efficiency of the developed CO2 laser had exceeded the value η∼ 21% at E∼ 350 mJ. At the beginning of 2022, it was shown that xenon addition (Xe = 4%) to the gas mixture made it possible to achieve an efficiency of η∼ 27% at an output energy of E∼ 600 mJ. For the first time, the effect of hydrogen additives in the active medium (He:N2:CO2:H2 and N2:CO2:H2 gas mixtures) was investigated for a pulsed inductive CO2 laser with RF excitation depending on the RF-pumping pulse duration value (τ), which allows the energy and temporal radiation characteristics of the laser to be controlled over a wider range. In addition to those already published, new experimental data have been obtained, namely the output beam profile of the inductive CO2 laser based on He:N2:CO2 = 8:2:1 gas mixture depending on the τ value. The new data will improve our understanding of inductive CO2 laser physics and of the plasma–chemical processes occurring in its active medium. RF current pulses propagated along inductor wires and, thus, an inductive discharge was formed to create a population inversion by IR transitions of CO2
* molecules.
Analysis of the neural mechanism of spectra decrease in MCI by a thalamo-cortical coupled neural mass model
Authors: Cui Dong , Li Han , Liu Pengxiang , Gu Guanghua , Li Xiaoli , Wang Lei , Yin Shimin 
Published: December 2022

Abstract

Objective. In order to deeply understand the neurophysiological mechanism of the spectra decrease in mild cognitive impairment (MCI), this paper studies a new neural mass model, which can simulate various intracerebral electrophysiological activities. Approach. In this study, a thalamo-cortical coupled neural mass model (TCC-NMM) is proposed. The influences of the coupling coefficients and other key parameters on the model spectra are simulated. Then, the unscented Kalman filter (UKF) algorithm is used to reversely identify the parameters in the TCC-NMM. Furthermore, the TCC-NMM and UKF are combined to analyze the spectra reduction mechanism of electroencephalogram (EEG) signals in MCI patients. The independent sample t-test is carried out to statistical analyze the differences of the identified parameters between MCI and normal controls. The Pearson correlation analysis is used to analyze the intrinsic relationship between parameters and the scores of the comprehensive competence assessment scale. Main results. The simulation results show that the decreased cortical synaptic connectivity constants C
1 can result in spectra decrease of the TCC-NMM outputs. The real EEG analysis results show that the identified values of parameter C
1 are significant lower in the MCI group than in control group in frontal and occipital areas and the parameters C
1 are positively correlated with the Montreal Cognitive Assessment (MoCA) scores in the two areas. This consistency suggests that the cortical synaptic connectivity loss from pyramidal cells to excitatory interneurons (eIN) may be one of the neural mechanisms of EEG spectra decrease in MCI. Significance. (a) In this study, a new mathematical model TCCNMM based on anatomy and neurophysiology is proposed. (b) All key parameters in TCC-NMM are studied in detail through the forward and reverse analysis and the influence of these parameters on the output spectra of the model is pointed out. (c) The possible neural mechanism of the decreased spectra in MCI patients is pointed out by the joint analysis of simulation in forward with TCC-NMM and analysis of the actual EEG signals in reverse with UKF identification algorithm. (d) We find that the identified parameter C1 of MCI patients is significantly lower than that of the control group, which is consistent with the simulation analysis of TCC-NMM. So, we suggest that the decreased MCI alpha power spectrum is likely related to the cortical synaptic connection loss from pyramidal cells to eIN.
Identification and classification of epileptic EEG signals using invertible constant-Q transform-based deep convolutional neural network
Authors: Eltrass Ahmed S , Tayel Mazhar B , EL-qady Ahmed F 
Published: December 2022

Abstract

Context. Epilepsy is the most widespread disorder of the nervous system, affecting humans of all ages and races. The most common diagnostic test in epilepsy is the electroencephalography (EEG). Objective. In this paper, a novel automated deep learning approach based on integrating a pre-trained convolutional neural network (CNN) structure, called AlexNet, with the constant-Q non-stationary Gabor transform (CQ-NSGT) algorithm is proposed for classifying seizure versus seizure-free EEG records. Approach. The CQ-NSGT method is introduced to transform the input 1D EEG signal into 2D spectrogram which is sent to the AlexNet CNN model. The AlexNet architecture is utilized to capture the discriminating features of the 2D image corresponding to each EEG signal in order to distinguish seizure and non-seizure subjects using multi-layer perceptron algorithm. Main results. The robustness of the introduced CQ-NSGT technique in transforming the 1D EEG signals into 2D spectrograms is assessed by comparing its classification results with the continuous wavelet transform method, and the results elucidate the high performance of the CQ-NSGT technique. The suggested epileptic seizure classification framework is investigated with clinical EEG data acquired from the Bonn University database, and the experimental results reveal the superior performance of the proposed framework over other state-of-the-art approaches with an accuracy of 99.56%, sensitivity of 99.12%, specificity of 99.67%, and precision of 98.69%. Significance. This elucidates the importance of the proposed automated system in helping neurologists to accurately interpret and classify epileptic EEG records without necessitating tedious visual inspection or massive data analysis for long-term EEG signals.
Drugless nanoparticles tune-up an array of intertwined pathways contributing to immune checkpoint signaling and metabolic reprogramming in triple-negative breast cancer
Authors: Ramzy Asmaa , ElSafy Sara , Elshoky Hisham A , Soliman Aya , Youness Rana , Mansour Samar , Sebak Aya 
Published: December 2022

Abstract
Metabolic reprogramming ‘Warburg effect’ and immune checkpoint signaling are immunosuppressive hallmarks of triple-negative breast cancer (TNBC) contributing to the limited clinical applicability of immunotherapy. Biomaterials arise as novel tools for immunomodulation of the tumor microenvironment that can be used alongside conventional immunotherapeutics. Chitosan and lecithin are examples of versatile biomaterials with interesting immunomodulatory properties. In this study, we aimed at investigation of the role of carefully designed hybrid nanoparticles (NPs) on common mediators of both programmed death ligand 1 (PD-L1) expression and glycolytic metabolism. Hybrid lecithin–chitosan NPs were prepared and characterized. Their intracellular concentration, localization and effect on the viability of MDA-MB-231 cells were assessed. Glycolytic metabolism was quantified by measuring glucose consumption, adenosine triphosphate (ATP) generation, lactate production and extracellular acidification. Nitric oxide production was quantified using Greiss reagent. Gene expression of inducible nitric oxide synthase (iNOS), phosphatidylinositol-3-kinase (PI3K), protein kinase B (PKB or Akt), mammalian target of rapamycin (mTOR), hypoxia-inducible factor 1α (HIF-1α) and PD-L1 was quantified by quantitative reverse transcription polymerase chain reaction (q-RT-PCR). Chitosan, lecithin and the NPs-formulated forms have been shown to influence the ‘Warburg effect’ and immune checkpoint signaling of TNBC cells differently. The composition of the hybrid systems dictated their subcellular localization and hence the positive or negative impact on the immunosuppressive characteristics of TNBC cells. Carefully engineered hybrid lecithin–chitosan NPs could convert the immune-suppressive microenvironment of TNBC to an immune-active microenvironment via reduction of PD-L1 expression and reversal of the Warburg effect.
Energy and food security implications of transitioning synthetic nitrogen fertilizers to net-zero emissions
Authors: Rosa Lorenzo , Gabrielli Paolo 
Published: December 2022

Abstract
By synthetically producing nitrogen fertilizers from ammonia (NH3), the Haber–Bosch process has been feeding humanity for more than one hundred years. However, current NH3 production relies on fossil fuels, and is energy and carbon intensive. This commits humanity to emissions levels not compatible with climate goals and commits agricultural production to fossil fuels dependency. Here, we quantify food and energy implications of transitioning nitrogen fertilizers to net-zero CO2 emissions. We find that 1.07 billion people are fed from food produced from imported nitrogen fertilizers. An additional 710 million people are fed from imported natural gas feedstocks used for fertilizers production, meaning that 1.78 billion people per year are fed from imports of either fertilizers or natural gas. These findings highlight the reliance of global food production on trading and fossil fuels, hence its vulnerability to supply and energy shocks. However, alternative routes to achieve net-zero emissions in NH3 production exist, which are based on carbon capture and storage, electrification, and biomass. These routes comply with climate targets while mitigating the risks associated with food security. Yet, they require more land, energy, and water than business-as-usual production, exacerbating land and water scarcity and the use of limited natural resources. Transitioning fertilizers to net-zero emissions can contribute to climate and food security goals, although water, land, and energy trade-offs should be considered.
The single-point Berry phase in condensed-matter physics
Authors: Resta Raffaele 
Published: December 2022

Abstract
The Berry phase plays an outstanding role in condensed-matter physics, where it provides the main entry for defining and computing a key observable: macroscopic electrical polarization. This phase obtains as a loop integral in reciprocal space, which has the topology of a torus. I show here that in some circumstances the loop may be contracted to a point, and polarization can be computed in practice from a single Hamiltonian diagonalization.
Optimization of process parameters and mechanism of strengthening and toughening of Nb-W alloy prepared by chemical vapor deposition based on orthogonal test
Authors: Mao Zhang , Xian Wang , Qin-qin Gao , Chang-yi Hu , Jun Zhao , Hong-zhong Cai , Gui-xue Zhang , Xing-qiang Wang , Xu-xiang Zhang , Ying-zhi AN , Yan Wei 
Published: December 2022

Abstract
In this paper, the chemical vapor deposition (CVD) method was used to prepare Nb-W binary alloys on Mo substrates for the first time. The influences of the process parameters on the composition, average deposition rate, and average deposition efficiency of the Nb-W alloys were studied by orthogonal experiments. Nb-W alloys with W contents ranging from 0.33% to 50.48% were successfully prepared. The mechanical properties and fracture morphologies of the Nb-W alloys prepared by the CVD method (CVDNb-W alloys) were tested by metallographic microscopy, scanning electron microscopy, electron probe analysis, and in situ tensile tests. The results showed that the Nb-W alloy prepared by the CVD method had uneven macroscopic distributions of Nb and W.The substrate temperature had the greatest influence on the lateral composition gradient, and the H2 flow had the least influence. The influence of the Cl2 flow through the Nb and W on the average deposition rate was also examined. The chlorination temperature of W had the least effect on the average deposition rate, and the average deposition efficiency decreased with the increase in the gaseous chloride ratio of W. The effects of other factors on the average deposition efficiency showed different degrees of wave dynamics. The metallographic observation of 16 samples showed that except for samples 3# and 4# (in which the mass percentages of W were less than 1%), the microstructures of the other samples (in which the mass percentages of W were all more than 1%) showed similar microstructures with layered structural features. Comprehensive analysis of the sample and inverse pole figures revealed that the (101)

11

1
¯

textural component mainly existed in the CVDNb-W alloys.With the increase in the mass percentage of W, the tensile strength of the CVDNb-W alloy increased correspondingly. The maximum strength of the alloy containing 9.68% W by mass reached 475 MPa, which exceeds the room-temperature tensile strength of Nb521, but the elongation at break was related to the alloy composition. Thus, the relationship did not show a discernible trend.