bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preparation of multilayer samples for scanning thermal microscopy examination
Authors: Lees James , Corbetta Marco , Kleine-Boymann Matthias , Scheidemann Adi , Poon Siew Wai , Thompson Sarah M 
Published: February 2024

Abstract
Thin film multilayer materials are very important for a variety of key technologies such as hard drive storage. However, their multilayered nature means it can be difficult to examine them after production and determining properties of individual layers is harder still. Here, methods of preparing multilayer samples for examination using scanning thermal microscopy are compared, showing that both a combination of mechanical and ion beam polishing, and ion beam milling to form a crater produce suitable surfaces for scanning thermal microscopy examination. However, the larger exposed surfaces of the ion beam milled crater are the most promising for distinguishing between the layers and comparison of their thermal transport properties.
Enhanced LWIR response of InP/InAsP quantum discs-in-nanowire array photodetectors by photogating and ultra-thin ITO contacts
Authors: Jeddi Hossein , Adham Kristi , Zhao Yue , Witzigmann Bernd , Römer Friedhard , Bermeo Marie , Borgström Magnus T , Pettersson Håkan 
Published: February 2024

Abstract
Here we report on an experimental and theoretical investigation of the long-wavelength infrared (LWIR) photoresponse of photodetectors based on arrays of three million InP nanowires with axially embedded InAsP quantum discs. An ultra-thin top indium tin oxide contact combined with a novel photogating mechanism facilitates an improved LWIR normal incidence sensitivity in contrast to traditional planar quantum well photodetectors. The electronic structure of the quantum discs, including strain and defect-induced photogating effects, and optical transition matrix elements were calculated by an 8-band k·p simulation along with solving drift-diffusion equations to unravel the physics behind the generation of narrow linewidth intersubband signals observed from the quantum discs.
Suppressing HIFU interference in ultrasound images using 1D U-Net-based neural networks
Authors: Yang Kun , Li Qiang , Liu Hengxin , Zeng Qingxuan , Cai Dejia , Xu Jiahong , Zhou Yingying , Tsui Po-Hsiang , Zhou Xiaowei 
Published: February 2024

Abstract

Objective. One big challenge with high-intensity focused ultrasound (HIFU) is that the intense acoustic interference generated by HIFU irradiation overwhelms the B-mode monitoring images, compromising monitoring effectiveness. This study aims to overcome this problem using a one-dimensional (1D) deep convolutional neural network. Approach. U-Net-based networks have been proven to be effective in image reconstruction and denoising, and the two-dimensional (2D) U-Net has already been investigated for suppressing HIFU interference in ultrasound monitoring images. In this study, we propose that the one-dimensional (1D) convolution in U-Net-based networks is more suitable for removing HIFU artifacts and can better recover the contaminated B-mode images compared to 2D convolution. Ex vivo and in
vivo HIFU experiments were performed on a clinically equivalent ultrasound-guided HIFU platform to collect image data, and the 1D convolution in U-Net, Attention U-Net, U-Net++, and FUS-Net was applied to verify our proposal. Main results. All 1D U-Net-based networks were more effective in suppressing HIFU interference than their 2D counterparts, with over 30% improvement in terms of structural similarity (SSIM) to the uncontaminated B-mode images. Additionally, 1D U-Nets trained using ex vivo datasets demonstrated better generalization performance in in
vivo experiments. Significance. These findings indicate that the utilization of 1D convolution in U-Net-based networks offers great potential in addressing the challenges of monitoring in ultrasound-guided HIFU systems.
Hall physics during magnetic reconnection with collision effect
Authors: Shu Yukang , Lu San , Lu Quanming , Huang Kai , Wang Rongsheng , Ding Weixing 
Published: February 2024

Abstract
The Hall effect, decoupling between the ion and electron motions, is the core mechanism triggering fast reconnection. In plasmas with collision effects such as laboratory facilities, collision can suppress the Hall effect and influence the triggering of fast reconnection. Here, by conducting a series of kinetic simulations with varying collision parameters, we show that collisions can suppress the electron outflow, impairing the quadrupole Hall magnetic field. Besides, collision weakens the inflow of magnetic flux by reducing the charge separation and increasing the thermal pressure at the reconnection site, leading to a reduction of the Hall electric field. As the collisionality becomes larger, the Hall electric field diminishes more easily than the Hall magnetic field. We propose that the quadrupolar Hall magnetic field can be a significant indicator in reflecting Hall reconnection.
Simulations of tokamak edge plasma turbulent fluctuations based on a minimal 3D model
Authors: Umansky M V , Cohen B I , Joseph I 
Published: February 2024

Abstract
A new simulation model for tokamak boundary plasma, SOLT3D, is implemented in the BOUT++ framework (Dudson et al 2009 Comput. Phys. Commun.
180 1467). The simulation model includes a set of dynamic equations describing collisional boundary plasma and neutral gas in the tokamak scrape-off layer and divertor region. The model is verified against standard linear plasma instabilities and available nonlinear results. For L-mode like conditions, SOLT3D reproduces characteristics of boundary plasma turbulent fluctuations that are similar to published experimental data, in terms of the amplitude and spatial dependence of the fluctuations. It also reproduces realistic plasma fluxes on material surfaces and expected Bohm-like effective radial transport. Plasma fluctuations inferred from the simulations imply inevitably a significant level of intrinsic ‘noise’ for axisymmetric tokamak plasma transport modeling, introducing errors on the order of unity. In particular, the toroidally averaged atomic rates below 5–10 eV are strongly modified by turbulent plasma fluctuations, which should significantly affect the standard axisymmetric modeling of the tokamak edge plasma and divertor.
The surface force balance: direct measurement of interactions in fluids and soft matter
Authors: Hayler Hannah J , Groves Timothy S , Guerrini Aurora , Southam Astrid , Zheng Weichao , Perkin Susan 
Published: February 2024

Abstract
Over the last half-century, direct measurements of surface forces have been instrumental in the exploration of a multitude of phenomena in liquid, soft, and biological matter. Measurements of van der Waals interactions, electrostatic interactions, hydrophobic interactions, structural forces, depletion forces, and many other effects have checked and challenged theoretical predictions and motivated new models and understanding. The gold-standard instrument for these measurements is the surface force balance (SFB), or surface forces apparatus, where interferometry is used to detect the interaction force and distance between two atomically smooth planes, with 0.1 nm resolution, over separations from about 1 µm down to contact. The measured interaction force vs. distance gives access to the free energy of interaction across the fluid film; a fundamental quantity whose general form and subtle features reveal the underlying molecular and surface interactions and their variation. Motivated by new challenges in emerging fields of research, such as energy storage, biomaterials, non-equilibrium and driven systems, innovations to the apparatus are now clearing the way for new discoveries. It is now possible to measure interaction forces (and free energies) with control of electric field, surface potential, surface chemistry; to measure time-dependent effects; and to determine structure in situ. Here, we provide an overview the operating principles and capabilities of the SFB with particular focus on the recent developments and future possibilities of this remarkable technique.
Enhancing levitation force of superconductors through wavelength optimization in Halbach permanent magnet arrays
Authors: Liu Xiaoning , Si Mayin , Ke Zhihao , Deng Zigang 
Published: February 2024

Abstract
Optimizing the wavelength (γ) of the Halbach array permanent magnet guideway (PMG) in superconducting maglev systems can improve levitation performance without consuming additional materials. The value of γ impacts the external field intensity

H

e

and gradient

∇

H

e

generated by the PMG. The total amount of magnetic field energy is fixed, and the γ essentially regulates the distribution of this energy. Reducing γ concentrates more magnetic field on the PMG surface, resulting in larger force and stiffness when the levitation height approaches zero. To validate this conclusion, experiments, approximate calculations and numerical simulations have been in all employed. However, excessive reducing γ at higher heights is not ideal as it tends to distribute most of the field energy below the desired height. The approximate method in this paper indicates that the levitation force is positively correlated with

(

H

e

2

2

H

p

−

H

e

)
∇

H

e

. Therefore, the objective is to determine the optimal γ that maximizes this index. Optimal values for γ at different heights have been identified, offering guidance for PMG design. Additionally, applying these findings to two existing PMGs results in 18% and 8.6% augmentation in levitation force respectively. Furthermore, a fully optimized PMG design has the potential to achieve a levitation force of nearly 10 kN m−1, while keeping the cross-sectional areas of the PMG and SC restricted to 4450 mm2 and 2500 mm2, respectively.
Flux transfer circuits breaking conventional limit in transfer coefficient based on a negative inductance of a π-junction
Authors: Higashi Masayuki , Li Feng , Tanaka Masamitsu , Fujimaki Akira 
Published: February 2024

Abstract
We have demonstrated transfer coefficients breaking the conventional limit in flux transfer circuits (FTCs) by introducing a π-phase-shifted Josephson junction (π-junction), where the FTCs include an input/output inductor. According to the current-phase relationship of a π-junction, the π-junction behaves as an inductor with intrinsically negative kinetic inductance. When a single-π-junction superconducting quantum interference device (π-SQUID) in which a geometric inductor is placed in parallel with the π-junction is formed, a current flowing on the inductor, that is, the internal flux is increased against an input current or an input flux supplied externally to the π-SQUID in case that the π-SQUID shows no hysteresis in characteristics of internal-external flux. The FTC under investigation (π-FTC) is composed of two identical π-SQUIDs sharing a π-junction. The magnitude of the internal flux exceeds that of the external flux in the π-SQUID near zero external flux. Using this effect, the transfer coefficients are expected to be increased in the π-FTCs. Numerical analysis for π-FTCs reveals that the transfer coefficients exceed the conventional limit in a wide range of input currents corresponding to the input flux, although the negative kinetic inductance depends on the magnitude of the input. We made several π-FTCs for critical currents of the π-junctions of 50 πA and 60 πA. The output flux was measured by constructing a flux-locked loop. The experimentally obtained ratios of the transfer coefficients of the π-FTCs to the coefficient of the conventional FTC made on the same chip agree with the numerical results, which supports the negative kinetic inductances cause the increased coefficients breaking the conventional limit. Because the transfer coefficient is almost independent of input currents, we believe that the π-FTCs are applicable for strengthening not only couplings used in quantum annealers or SQUID sensors but also couplings used in superconductor digital circuits.
A hydrodynamical description of Bose liquid with fractional exclusion statistics
Authors: Fei Zhaoyu , Chen Yu 
Published: February 2024

Abstract
Hydrodynamical systems are usually taken as chaotic systems with fast relaxations. It is counter intuitive for ‘ideal’ gas to have a hydrodynamical description. We find that a hydrodynamical model of one-dimensional

|

Φ

|

6

theory shares the same ground state density profile, density-wave excitation, as well as the similar dynamical and statistical properties with the Calogero–Sutherland model in thermodynamic limit when their interaction strengths matches each other. The interaction strength g
0 in

|

Φ

|

6

theory is then the index of fractional statistics. Although the model is interacting in Bose liquid sense, but it shows integrability with periodical coherent evolution. We also discussed the fractional statistics emerges from the

|

Φ

|

6

theory.
Universality of oscillatory instabilities in fluid mechanical systems
Authors: García-Morales Vladimir , Tandon Shruti , Kurths Jürgen , Sujith R I 
Published: February 2024

Abstract
Oscillatory instability emerges amidst turbulent states in experiments in various turbulent fluid and thermo-fluid systems such as aero-acoustic, thermoacoustic and aeroelastic systems. For the time series of the relevant dynamic variable at the onset of the oscillatory instability, universal scaling behaviors have been discovered in experiments via the Hurst exponent and certain spectral measures. By means of a center manifold reduction, the spatiotemporal dynamics of these real systems can be mapped to a complex Ginzburg–Landau equation with a linear global coupling. In this work, we show that this model is able to capture the universal behaviors of the route to oscillatory instability, elucidating it as a transition from defect to phase turbulence mediated by the global coupling.
Dynamical analysis of a new 3D chaotic system: non-equilibrium point, conservative, rotationally hidden attractor
Authors: Zhao Boyu , Ye Xiaolin 
Published: February 2024

Abstract
A novel three-dimensional chaotic system is proposed in this paper. The nonlinear features are enhanced by adding e-exponent function to make the system behavior more complex and diverse. Through calculation and experimental verification, it is found that the system is a conservative system without equilibrium point, and this kind of system may produce hidden dynamic behavior. Therefore, four different dynamic analysis tools are chosen to simulate the possible hidden dynamics. The rotation factor is used to create some new models on the original system equation. With constantly adjustments of the rotation angle, the different resulting rotational hidden attractors are used to further prove that such chaos exists in the new proposed system. In the end, the realization of DSP shows the feasibility of this system in practical applications.
Chaotic model and control of an atmospheric convective system coupled with large-scale circulation
Authors: Zhang Fangfang , Liu Wenzhe , Wu Lin , Li Jie 
Published: February 2024

Abstract
Large-scale weather systems affect or determine the generation, development and movement of small- and medium-scale convective weather systems, and the understanding of their influence mechanism is of great significance for the prediction and forecasting of small- and medium-scale convective systems. From the perspective of dynamics, based on the Lorenz–Stenflo model describing convective systems and the Lorenz84 model describing low-order atmospheric circulation, we constructed a chaotic model of an atmospheric convective system considering large-scale circulation, analyzed the influence of the system parameters on the convective system, and designed a state feedback controller to adjust the convective motion. For the constructed convective weather system model, the existence and boundedness of its solution were analyzed, the Hamiltonian quantity was solved, the dynamic characteristics of the Lyapunov exponent, bifurcation diagram, attractor phase diagram and other methods were used to analyze its dynamic characteristics, the physical significance of its dynamic behavior was discussed, and the influence mechanism of the system parameters on convective weather was given. Additionally, the temperature difference between the upper and lower air currents is changed by the state feedback method, which provides a feasible scheme for adjusting the intensity of convective motion. The simulation experiments show that the chaotic model can explain and reveal the complex dynamic behavior of large-scale weather circulation in small- and medium-scale convective systems, which is of great significance for improving the prediction accuracy of convective systems in local areas, and feedback control can obtain the desired convective motion state.
Frequency-dependent membrane polarization across neocortical cell types and subcellular elements by transcranial alternating current stimulation
Authors: Huang Xuelin , Wei Xile , Wang Jiang , Yi Guosheng 
Published: February 2024

Abstract

Objective. Transcranial alternating current stimulation (tACS) is a non-invasive brain stimulation technique that directly interacts with ongoing brain oscillations in a frequency-dependent manner. However, it remains largely unclear how the cellular effects of tACS vary between cell types and subcellular elements. Approach. In this study, we use a set of morphologically realistic models of neocortical neurons to simulate the cellular response to uniform oscillating electric fields (EFs). We systematically characterize the membrane polarization in the soma, axons, and dendrites with varying field directions, intensities, and frequencies. Main results. Pyramidal cells are more sensitive to axial EF that is roughly parallel to the cortical column, while interneurons are sensitive to axial EF and transverse EF that is tangent to the cortical surface. Membrane polarization in each subcellular element increases linearly with EF intensity, and its slope, i.e. polarization length, highly depends on the stimulation frequency. At each frequency, pyramidal cells are more polarized than interneurons. Axons usually experience the highest polarization, followed by the dendrites and soma. Moreover, a visible frequency resonance presents in the apical dendrites of pyramidal cells, while the other subcellular elements primarily exhibit low-pass filtering properties. In contrast, each subcellular element of interneurons exhibits complex frequency-dependent polarization. Polarization phase in each subcellular element of cortical neurons lags that of field and exhibits high-pass filtering properties. These results demonstrate that the membrane polarization is not only frequency-dependent, but also cell type- and subcellular element-specific. Through relating effective length and ion mechanism with polarization, we emphasize the crucial role of cell morphology and biophysics in determining the frequency-dependent membrane polarization. Significance. Our findings highlight the diverse polarization patterns across cell types as well as subcellular elements, which provide some insights into the tACS cellular effects and should be considered when understanding the neural spiking activity by tACS.
Taxonomic fingerprints of Plantago atrata Hoppe – a Review
Authors: Ivanov G , Kercheva A , Tosheva A , Yordanova Z , Zhiponova M 
Published: February 2024

Abstract

Plantago atrata Hoppe (dark plantain; Plantaginaceae) is a lesser-studied narrow-leaved Plantain species and in the present review, we summarize the knowledge about the plant. The distribution of this alpine species and reported subspecies is described. Emphasis is made on P. atrata taxonomic features including botanical characteristics and phylogenetic discrimination via DNA barcoding and metabolic composition. The ecological significance of this plant species is discussed from floristic and nutrient value points of view. The collected information would serve as a basis for further in-depth research on physiological and phytochemical aspects of P. atrata, which would enable the understanding of this plant’s high-altitude adaptation and its possible contribution to beneficial applications for other organisms.
Accumulation of microplastics in Zebra mussel (Dreissena polymorpha, Pallas, 1771) in the sand pit lake Kazichene, Bulgaria
Authors: Hongyu Zhang , Rozdina Desislava , Kozuharov Dimitar , Traykov Ivan 
Published: February 2024

Abstract
In recent years, microplastic contamination has received worldwide distribution and specific attention. As a result, detecting sensitive bioindicators is crucial to establish the pollution. The aim of the present study is to investigate the accumulation of microplastics in zebra mussels (Dreissena polymorpha, Pallas, 1771) from the sand pit lake Kazichene. The natural range of the zebra mussel in Bulgaria includes the Danube River delta, the Black Sea rivers and coastal lakes. However, it is considered a wide spread invasive species to inland freshwaters. The use of invasive species as bioindicators over native species is advisable in order to protect the local biodiversity. In total 20 mussels of D. polymorpha were used for the analysis. The biological tissues of the mussels were digested with the aid of 30% H2O2 at 65°C for 24 - 48 hours. Microplastics (772 pcs. in total) were detected in all zebra mussel samples, indicating microplastic contamination in Lake Kazichene. Three main shapes have been identified: fragments, fibres and pellets, with the highest proportion of the fragments. The colours of the microplastic particles found were black, red, yellow and transparent, dominated by those of black colour, followed by red. The length of the fibres found in the zebra mussels ranged from 0.25 to 5 mm. There was no strong correlation between the body length/meat weight of zebra mussels with the degree of microplastic accumulation in the mussels.
Evaluation of behavioral response of Blitopertha lineolata (Fischer von Waldheim, 1824) (Coleoptera: Rutelidae) to visual and chemical cues
Authors: Toshova Teodora , Tóth Miklós , Subchev Mitko , Abaev Vasiliy , Guéorguiev Borislav 
Published: February 2024

Abstract
During field trapping of Tropinota hirta (Cetoniidae) by blue traps baited with the respective floral lure regular catches Blitopertha lineolata were recorded in an experimental field in Sofia plain, Bulgaria. In order to investigate the relative importance of chemical and visual cues on the attraction response of this species, several field tests were performed using CSALOMON® VARb3k funnel traps in Sofia during 2007-2009. In 2007, we evaluated the behavioral response of the adults to four variants of traps - transparent and blue unbaited traps, and transparent and blue traps baited with the lure for T. hirta. The most numerous catches of B. lineolata were recorded in blue traps independently of the presence or absence of the floral bait. In a subsequent test we compared the attractiveness of baited traps developed for cetoiid beetle species: T. hirta, Oxythyrea funesta, Cetonia aurata and Protaetia cuprea (Cetoniidae). The most numerous catches were recorded in traps for C. aurata/P. cuprea but there was no significant difference between mean catches in these traps and traps for T. hirta. The color preference of B. lineolata was evaluated comparing the colors, white, blue, yellow, fluorescent yellow or transparent of VARb3 traps without chemical lures. Results of these tests revealed that highest mean numbers of adults were recorded in the blue traps followed by the fluorescent yellow traps in 2008, and white and yellow traps in 2009. During this study, the seasonal flight of B. lineolata in the Sofia region started at the second half of May and lasted till the beginning of July in 2007, 2008 and 2009. Blue CSALOMON® VARb3k funnel traps can be considered as an efficient tool for detection and monitoring the seasonal flight of this species. Further research is needed to find a semiochemical attractant to B. lineolata. New distributional data for this species in Bulgaria are provided as well.