bluuebunny/crossref_metadata_2025_split huggingface dataset:
Collaborative multi-feature extraction and scale-aware semantic information mining for medical image segmentation
Authors: Zhang Ruijun , He Zixuan , Zhu Jian , Yuan Xiaochen , Huang Guoheng , Pun Chi-Man , Peng Jianhong , Lin Junzhong , Zhou Jian 
Published: September 2022

Abstract

Objective. In recent years, methods based on U-shaped structure and skip connection have achieved remarkable results in many medical semantic segmentation tasks. However, the information integration capability of this structure is still limited due to the incompatibility of feature maps of encoding and decoding stages at corresponding levels and lack of extraction of valid information in the final stage of encoding. This structural defect is particularly obvious in segmentation tasks with non-obvious, small and blurred-edge targets. Our objective is to design a novel segmentation network to solve the above problems. Approach. The segmentation network named Global Context-Aware Network is mainly designed by inserting a Multi-feature Collaboration Adaptation (MCA) module, a Scale-Aware Mining (SAM) module and an Edge-enhanced Pixel Intensity Mapping (Edge-PIM) into the U-shaped structure. Firstly, the MCA module can integrate information from all encoding stages and then effectively acts on the decoding stages, solving the problem of information loss during downsampling and pooling. Secondly, the SAM module can further mine information from the encoded high-level features to enrich the information passed to the decoding stage. Thirdly, Edge-PIM can further refine the segmentation results by edge enhancement. Main results. We newly collect Magnetic Resonance Imaging of Colorectal Cancer Liver Metastases (MRI-CRLM) dataset in different imaging sequences with non-obvious, small and blurred-edge liver metastases. Our method performs well on the MRI-CRLM dataset and the publicly available ISIC-2018 dataset, outperforming state-of-the-art methods such as CPFNet on multiple metrics after boxplot analysis, indicating that it can perform well on a wide range of medical image segmentation tasks. Significance. The proposed method solves the problem mentioned above and improved segmentation accuracy for non-obvious, small and blurred-edge targets. Meanwhile, the proposed visualization method Edge-PIM can make the edge more prominent, which can assist medical radiologists in their research work well.
Above-100 MeV proton beam generation from near-critical-density plasmas irradiated by moderate Laguerre–Gaussian laser pulses
Authors: Hu Yan-Ting , Cao Yue , Zhao Jie , Zhang Guo-Bo , Liu Ke , Hu Li-Xiang , Yu Tong-Pu 
Published: September 2022

Abstract
High-quality protons have many potential applications in tumor therapy, proton radiography, fast ignition and nuclear physics. Over recent decades, significant progress has been made in generating such proton beams with lasers. However, it is still challenging to achieve a compact proton beam with an energy of hundreds of MeV under the laser intensities currently available. Here, we propose a novel scheme to produce above-100 MeV protons in nonuniform near-critical-density (NCD) plasmas driven by a Laguerre–Gaussian (LG) laser pulse. When a linearly-polarized LG laser pulse with the intensity of ∼1020 W cm−2 enters the NCD plasmas with a trapezoidal density profile, a donut-like double-channel structure with an electron column on the axis is produced behind the laser pulse, together with a unique, strong magnetic field. At the end of the density plateau, the magnetic field begins to expand in both longitudinal and transverse directions. The magnetic pressure force displaces the electrons with regard to the protons, resulting in a quasi-static electric field

E

x

S

. This electrostatic field can remain robust and be sustaintained for a long time since the magnetic field decreases very slowly, i.e.

E

x

S

∝
▽

B

z

2

. Thus, the protons can be accelerated by the longitudinal electrostatic field and confined by the generated transverse focusing field. Three dimensional particle-in-cell simulations confirmed that a well-defined above-100 MeV proton beam with a cut-off energy at least 3.5 times larger than that of the normal Gaussian laser could be obtained, making the proton beams a potential source for tumor therapy in the future.
Influence of the magnetic field on properties of hot electron emission from ablative plasma produced at laser irradiation of a disc-coil target
Authors: Pisarczyk T , Renner O , Dudzak R , Chodukowski T , Rusiniak Z , Domanski J , Badziak J , Dostal J , Krupka M , Singh S , Klir D , Ehret M , Gajdos P , Zaras-Szydłowska A , Rosinski M , Tchórz P , Szymanski M , Krasa J , Burian T , Pfeifer M , Cikhardt J , Jelinek S , Kocourkova G , Batani D , Batani K , Santos J , Vlachos C , Ospina-Bohórquez V , Volpe L , Borodziuk S , Krus M , Juha L 
Published: September 2022

Abstract
Optical generators of strong magnetic fields based on the laser-driven-coil target concept are considered to be useful tools for studies of magnetized plasmas in particular, for the study of implosion of magnetized fusion targets in inertial fusion research and astrophysical applications. This paper presents the results of the research directed at an investigation of the plasma properties in a laser-induced magnetic field. In the experiment carried out on the kilojoule PALS laser facility, a generator of the magnetic field was a disc-coil (DC) target composed of a Cu disk coupled to a single-turn coil irradiated by a 1ω laser beam with an energy of 500 J. The attention was focused on examining the influence of the magnetic field on properties of the hot electron (HE) flux emitted from the front surface of the irradiated target. The three-frame complex interferometry and four-frame x-ray camera combined with the measurements of the HE population and energy using a multi-channel magnetic electron spectrometer and 2D-resolved imaging of the induced Cu Kα line emission were applied to characterize the ablative plasma and the generated particles. Based on the measured angular distributions of the electron energy spectra, 3D simulations have been performed to visualize the effect of the magnetic field on the HE flux and to provide information on space-time distribution of the electron and current density both without and with the presence of an axial magnetic field. The obtained results confirmed the possibility of generating magnetic fields above 5 T using the proposed DC target design as well as the significant impact of these fields on properties of the ablative plasma and the HE emission.
Dispersion relation and instability for an anisotropic nonuniform flowing plasma
Authors: Lee Min Uk , Yun Gunsu S , Ji Jeong-Young 
Published: September 2022

Abstract
A generalized formula for wave instability is developed for an anisotropic nonuniform plasma with finite flows and temperatures. Six-moment fluid equations are solved to give the analytic expression for wave instability in arbitrarily nonuniform plasmas. The analytic formula explicitly states the dependence of wave instability on the nonuniformities of number density, flow velocity, and anisotropic or isotropic pressure. The accuracy of the formalism is verified by a numerical calculation of implicit dispersion relations in complex Fourier space. The analysis shows that nonuniformity plays a critical role in plasma instability, while the flow velocity and anisotropic pressures determine the growth rate of the instability. The instability diagram and associated instability criterion for anisotropy-driven instability are introduced as applications of the formalism.
Experimental investigation on streamer inception from artificial hydrometeors
Authors: Mirpour S , Nijdam S 
Published: September 2022

Abstract
In this study we use an experimental investigation to shed light on the lightning inception problem. From atmospheric observations, it is known that the electric fields in thunderclouds are significantly lower than required for electric breakdown in air. One theory to explain lightning inception is that hydrometeors, i.e. any liquid or solid water particles formed in the atmosphere, greatly enhance the local electric field and can thereby initiate an electron avalanche leading to a streamer discharge. In this study, we investigate streamer initiation in the presence of artificial particles with different shapes. A metal or dielectric (TiO2) particle is suspended between a high-voltage and a grounded planar electrode which are separated by 16 cm in 50 mbar air. The particles are shaped as ellipsoids with a length of 8, 4, 2, and 1 cm and with different aspect ratios. A negative high voltage pulse is applied with a rise time of 30 ns, a pulse width of 1–10 μs, a repetition rate of 1 Hz, and a maximum voltage between 1 and 50 kV. Results show that the required background electric field for breakdown in the presence of a dielectric particle is decreased to 0.4 times the air breakdown field. Moreover, we observed bipolar streamer development from the particles where negative streamers are thicker and slightly slower than positive streamers. Finally, we found that streamers from longer particles are thicker and faster.
Expansion of surface barrier discharge scrutinized
Authors: Lindner M , Pipa A V , Brandenburg R , Schreiner R 
Published: September 2022

Abstract
Developing the fundamentals for the electrical diagnostics of surface dielectric barrier discharges (SDBDs) is of enormous importance for several applications, for example flow control and gas cleaning. The main challenge is to account for the discharge expansion along the dielectric surface. Typically, a linear expansion with the amplitude of the applied voltage is observed. In this work, we report on a step-wise SDBD expansion along the Al2O3 dielectric surface. More specific, the discharge occupied a certain area after ignition, which remained constant until the voltage exceeded the critical amplitude V

L
. This absence of expansion is seen as a linear dependence of the discharge power on the applied voltage and it was additionally confirmed by photographs with long exposure times. This novel phenomenon is more pronounced for thicker dielectrics. It is suggested that the derivative of the charge–voltage characteristics can be used for the determination of all essential parameters of the simplest equivalent circuit of SDBDs. Moreover, it was shown that the derivative of the charge–voltage characteristics for the positive half-cycle of the discharge agrees numerically with the voltage dependence of the reactor capacitance derived from photographs. This agreement between both measurement methods indicate a similar step-wise expansion of the SDBD even if a voltage amplitude above V

L
is applied
Splitting of ionization waves at the edge of a dielectric plate oriented at grazing angles between the helium plasma jet and the plate
Authors: Babaeva Natalia Yu , Naidis George V 
Published: September 2022

Abstract
In this paper, we discuss the results from the two-dimensional computational investigation of the effects of a helium plasma jet interacting with a dielectric plate at a floating potential. The plate is oriented at grazing angles formed between the plasma plume and the plate. We show that for angles α > 70° the jet plasma envelopes the plate and the splitting of an ionization wave (IW) at its edge is observed. As a result, one of the IWs propagates at some elevation over the upper surface of the plate. The other IW slides along the bottom surface as a surface discharge. This effect is partially attributed to the electric field direction and buoyancy forces which are especially important for the light helium channel surrounded by air. As such, the treatment of the top and bottom surfaces is not identical even for the horizontally oriented plate (α = 90°). We discuss the production and delivery to the plate surfaces the charged and neutral species important for applications. For the conditions considered, both sides of the plate are treated simultaneously. We also show that the buoyancy forces affect the reactive oxygen and nitrogen species distributions. For the helium jet which bends upward due to these forces, the best results for simultaneous treatment of thin plates can be achieved at grazing angles α = 80°–83°, but not at the angle of 90°. The choice of these particular incidence angles can provide better results. Locating the plate horizontally in parallel to the plasma jet axis can be dis-advantageous.
On the validity of the classical plasma conductivity in capacitive RF discharges
Authors: Wang Li , Vass Máté , Lafleur Trevor , Donkó Zoltán , Song Yuan-Hong , Schulze Julian 
Published: September 2022

Abstract
The plasma conductivity is an important input parameter for various plasma models. It is typically obtained from a simplified version of the electron momentum balance equation, where only a single inertia term and a simplified description of the collisional momentum transfer are included. The electric field is assumed to be a harmonic function of the driving frequency, higher harmonics of the current and spatial variations are neglected. Through particle-in-cell/Monte Carlo collision (PIC/MCC) simulations and analysis of the electric field generation based on velocity moments of the Boltzmann equation, the validity of this classical model is studied in capacitively coupled plasmas (CCPs). We find that these assumptions/simplifications result in significant inaccuracies of the conductivity in many cases. In single frequency CCPs, a deviation of more than an order of magnitude from the effective PIC-conductivity obtained from the simulations is found at low pressures in the discharge center and at the maximum sheath edge. In the center, this deviation is caused by neglecting the temperature gradient term in the momentum balance equation and adopting an approximation of the Ohmic term in the classical model, while at the maximum sheath edge it is induced by neglecting the density gradient term that accounts for the effect of the ambipolar electric field. The inaccuracy in the discharge center is reduced at higher pressures where the Ohmic term dominates and the approximations made in the classical model are more applicable. Better performance of the classical model is also found under conditions at which the inertia term included in the model plays an important role. Generally, neglecting higher harmonics of the current and spatial variations of plasma parameters is found to cause strong inaccuracies. Thus, the classical model can result in an inaccurate calculation of the power absorbed by electrons. Our results indicate that its applicability must be evaluated for a given set of conditions before using it to avoid introducing errors to plasma models.
Optimal design and experimental validation of 3D printed soft pneumatic actuators
Authors: Lu Yifu , Tong Liyong 
Published: September 2022

Abstract
This study develops a novel design of a unit cell-based bending-type soft pneumatic actuator, and formulates the design problem as compliant mechanisms under design-dependent pressure loadings. The proposed design is first optimized by using a topology optimization algorithm, in which the design-dependent loads and fluid-structure interface are tracked and formulated via finite element based approaches. Then, to validate the optimized design, it is modeled numerically using finite element analysis (FEA) and compared with the non-optimized traditional rectangular design. The optimal design can provide 19.5% improvements in bending angle. In addition, the proposed optimal design is prototyped using 3D printing. The prepared single actuator specimens are tested under pneumatic pressure, and the measured deformations are compared with those obtained from FEA. The results reveal that the optimized design can undergo large and compliant deformations under pneumatic pressure and generate a full (

360
∘

) bending. Furthermore, multiple actuator specimens of the proposed design are also assembled and integrated to prototype soft pneumatic grippers, with which several grasping tests are conducted. The adaptability and compatibility of the soft gripper are verified via gripping a wide range of irregular, soft, and fragile objects.
Energy exchange dependent transient ferromagnetic like state of ultrafast magnetization dynamics
Authors: Gao Shihan , Liu Donglin , Zheng Taotao , Ostler Thomas , Chantrell Roy , Xu Chudong 
Published: September 2022

Abstract
The study of laser-induced ultrafast magnetization dynamics is crucial for the development of information recording technology. Due to the complex mechanism, there is still a lack of comprehensive understanding for ultrafast magnetization dynamics. As an essential stage of laser-induced ultrafast magnetization switching process, the transient ferromagnetic like state (TFLS), has attracted much attention. Different from other studies on TFLS through the difference of magnetization dynamics between rare-earth and transition-metal, our study mainly focuses on the influence of energy injection and relaxation on TFLS in the process of ultrafast magnetization dynamics. The influence of various parameters on the formation of energy exchange dependent TFLS is studied. The results of simulation well support our view. Understanding the mechanism behind the TFLS is of great significance to promote the application of laser-induced ultrafast magnetization switching.
Design a new image encryption algorithm based on a 2D-ASCC map
Authors: Fei Xiaoyu , Zhang Jiujun , Qin Wenjie 
Published: September 2022

Abstract
In this paper, a new model of 2D absolute sine-cosine coupling (2D-ASCC) is proposed. In comparison with other 2D chaos map, the proposed system has higher complexity and better property of pseudo-random. It can effectively improve the security performance of encryption algorithm, if the proposed chaos map is applied in the design of image encryption algorithm based on chaos. Then, a new diffusion algorithm is designed based on the jumping diffusion. The plaintext is divided into two groups, and each group of plaintext is encrypted with a different formula. The pixel value of each ciphertext is composed of several non-adjacent pixels and the pseudo-random values generated by the proposed chaos map. In comparison with some existing encryption scheme, by using the design encryption scheme, the plaintext image can be completely encrypted in one iteration, it can significantly increase the security of algorithm and reduces the correlation between adjacent pixels. Finally, by using the numerical simulation and the security analysis, the effectiveness of the encryption algorithm is verified, and the comparison results show the higher security of the design encryption algorithm.
The SparSpec algorithm and the application to the detection of spatial periodicities in tokamaks: from a 1D to a 2D analysis
Authors: Testa D , Charrière J 
Published: September 2022

Abstract
A well-known, previously only 1D, algorithm using the Sparse Representation of Signals and an iterative Block Coordinate Descent method (the SparSpec-1D algorithm) has been further developed and tested in a 2D spatial domain to obtain the toroidal and poloidal periodicities of magnetic fluctuations in a tokamak. The tests are performed essentially using simulated data, because we know what the answer must be, and therefore it is straightforward to verify the accuracy of the algorithm. Two more examples using actual data from the JET and TCV tokamaks are considered to test the algorithm in real-life experiments; a further example using simulated data constructed from nominal test cases for the forthcoming ITER tokamak is also considered. The CPU run-time and the precision of the SparSpec-2D algorithm are studied as function of different analysis parameters. The stability of the algorithm is also tested via the introduction of random errors in the input signal. We find that the spatial-2D version of the baseline SparSpec-1D algorithm accurately finds the modes in the 2D toroidal and poloidal space, provided the set of magnetic sensors used for the analysis do not have a (quasi-)ignorable coordinate. The number of probes and their position are the key parameters that must be optimized for finding correct solutions. The main difficulty, as for the baseline SparSpec-1D algorithm, lies in dealing correctly with the intrinsic measurement uncertainties associated to the input magnetic fluctuation data, particularly the phase error, and this has been already separately reported in a companion work. However, the required CPU run-time for SparSpec-2D is significantly longer than that needed for 2 × SparSpec-1D, and thus SparSpec-2D is effectively suitable for use only when the 2 × 1D analyses cannot provide accurate results, which is the case when the set of measurements does not have an ignorable coordinate.
The influence of aluminum’s crystalline structure on the elastic, dielectric, and electrical properties of Ni ferrite
Authors: Arrasheed Enas A , Alibwaini Yamen A , Meaz T M , Ajlouni Abdul-Wali , Shalaby R M , Hemeda O M , Henaish A M A 
Published: September 2022

Abstract
The authors investigate the effect of Al on the structural, elastic, and electrical properties of a Ni nano ferrite. Six samples of NiAl

x

Fe
2−x
O
4 (where x = 0.00, 0.20, 0.40, 0.60, 0.80, and 1.00) were synthesized using flash auto combustion. As shown in XRD patterns, the lattice appears as a Fd-3m space group, a single-phase spinel structure with average crystallite size ranging from 22.4–24.7 nm for all samples. SEM and TEM images showed a uniform and spherical structural with a narrow size distribution. The results manifest significant changes in the elastic and electrical properties due to the presence of Al. As Al content increased, the bulk B, shear G, and Young E moduli decreased and remained in the same order of hundreds in the GPa range: however, the values of the Debye temperature θ

D
increased. The dielectric parameters ε′, ε″, and tan δ decreased as the frequency of the applied field and Al content increased: they also decreased as temperature increased. The relaxation times were

τ

ε

=

τ

tan

δ

=
0.1959

μ
s

for all samples. The electric moduli M′ and M″ increased as the frequency of the applied field and Al content increased, but they decreased as temperature increased. The relaxation times are dispersed depending on Al content, frequency, and temperature. The Cole-Cole curve showed two semicircles corresponding to the grain and grain boundary with the electrical relaxation of the non-Debye form. The electric impedance Z′ and Z″ increased as the frequency of the applied field and temperature increased, although they decreased as Al content increased. These results indicate that Ni-Al ferrite has respectable dielectric properties, which opens the door for many applications in control and safety monitoring tools, where dynamic process temperature sensors are of great importance and the temperature dependency of the material is significant.
PBH assisted search for QCD axion dark matter
Authors: Choi Gongjun , Schiappacasse Enrico D. 
Published: September 2022

Abstract
The entropy production prior to BBN era is one of ways to prevent QCD axion with the decay constant Fa
∈ [1012 GeV, 1016 GeV] from overclosing the universe when the misalignment angle is θ
i = 𝒪(1). As such, it is necessarily accompanied by an early matter-dominated era (EMD) provided the entropy production is achieved via the decay of a heavy particle. In this work, we consider the possibility of formation of primordial black holes during the EMD era with the assumption of the enhanced primordial scalar perturbation on small scales (k > 104 Mpc-1). In such a scenario, it is expected that PBHs with axion halo accretion develop to ultracompact minihalos (UCMHs). We study how UCMHs so obtained could be of great use in the experimental search for QCD axion dark matter with Fa
∈ [1012 GeV, 1016 GeV].