bluuebunny/crossref_metadata_2025_split huggingface dataset:
Galactic dynamics in general relativity: the role of gravitomagnetism
Authors: Ruggiero Matteo Luca , Ortolan Antonello , Speake Clive C 
Published: October 2022

Abstract
It is a well-known fact that, in the absence of dark matter, the observation of the rotation curves of galaxies cannot be explained in terms of Newtonian gravity. Rotation curves become flat in the outer regions, in contrast to what is expected according to Keplerian motion. Far from the galactic center, the gravitational field is supposed to be weak enough so we expect to be able to use Newtonian gravity; however, even in the weak-field approximation, there are general relativistic effects without a Newtonian counterpart, such as the gravitomagnetic effects originating from mass currents. Using the gravitoelectromagnetic approach to the solution of Einstein equations in the weak-field and slow-motion approximation, we discuss some simple arguments that suggest the surprising result that gravitomagnetic effects may have a relevant role in better understanding the impact of dark matter on galactic dynamics. In addition, treating matter as a fluid of dust, we study the influence of post-Newtonian effects on the fluid vorticity.
Redistribution of translational kinetic energy: the surprises of bounces
Authors: D’Angelo Christophe , Viennot Laurence , Argentina Médéric , Celestini Franck , Raufaste Christophe 
Published: October 2022

Abstract
The topic of collisions is introduced in university education to address the laws of conservation of momentum and energy. In particular, students are asked to classify collisions as either elastic or inelastic. They are often left with the idea that ‘macroscopic energy’ has been transformed into ‘microscopic energy’ in the case of an inelastic collision, but their understanding of the processes of redistribution of kinetic energy to other degrees of freedom, often called ‘dissipation’, is mostly very poor. The aim of this article is to see how to facilitate the understanding of these processes among university students. Firstly, the results of a questionnaire with 27 university students show that they consider mass and material as the most important determinants of the coefficient of restitution of the bounce of a ball on a solid and rigid support, while the notion of internal structure, which is however essential, is not considered. Second, a simple model contextualizes the idea of a temporal sequence of successive events in the rebound of inhomogeneous projectiles. Finally, recent results on bilayered projectiles are exploited to emphasize the non-trivial influence of the structure of a body on the restitution of its initial translational kinetic energy after rebound on a support. These different elements contribute to conceive possible teaching objectives, to propose simple experiments and to address the conditions for progress in this field.
Fabrication of microstructures in the bulk and on the surface of sapphire by anisotropic selective wet etching of laser-affected volumes
Authors: Capuano L , Berenschot J W , Tiggelaar R M , Feinaeugle M , Tas N R , Gardeniers J G E , Römer G R B E 
Published: October 2022

Abstract
In this paper a processing technique for sapphire is presented which combines laser-induced amorphization and subsequent selective wet etching of amorphized sapphire as well as anisotropic wet etching of single-crystalline sapphire (α-Al2O3). Using this technique, microstructures can be realized on the surface and in the bulk of sapphire substrates. By focusing ultra-short laser pulses inside sapphire, its structure can be transformed from crystalline into amorphous. The modified material can be selectively removed using etchants, such as hydrofluoric acid or potassium hydroxide (KOH), solely dissolving the amorphized part. In this work, however, an etchant consisting of a standard solution of sulphuric acid and phosphoric acid (96 vol% H2SO4: 85 vol% H3PO4, 3:1 vol%) at 180 °C is utilized. This method allows the realization of structures which are impossible to achieve when using conventional etchants which solely dissolve the amorphized sapphire. Ultrashort pulsed laser irradiation (230 fs) is used in this study as starting point for the subsequent anisotropic etching to form microstructures on the surface or in the bulk of sapphire that are terminated by characteristic crystal planes. In particular, the appearance of etching-induced patterns formed by stacks of rhombohedra is shown for structures below the surface, whereas triangular pits are achieved in surface processing.
Electron-impact ionization of the tantalum atom
Authors: Pindzola M S , Loch S D , Colgan J P 
Published: October 2022

Abstract
Electron-impact ionization cross sections for the ground configuration of the tantalum (Ta) atom are calculated using a combination of non-perturbative time-dependent close-coupling and perturbative distorted-wave methods. Direct ionization of the 6s and 5d subshells leading to single ionization are presented. The inclusion of a polarization potential in the 6s direct ionization leads to a small reduction in the cross section. Angular factors are included that allow the configuration-average direct ionization cross sections to be split into LS term resolution. The magnitude of the ionization cross section suggests that the ionization mean free path for neutral Ta will be similar to that for tungsten (W) plasma facing components in fusion experiments, leading to similarly large fractions of prompt redeposition.
Electron transport characteristics in dual gate-controlled 30 nm-thick silicon membrane
Authors: Zhao Shuai , Yuan Guodong , Zhang Di , Liu Yumeng , Lu Jun , Han Weihua , Luo Junwei 
Published: October 2022

Abstract
The exploration of multi-gate-controlled electron transport characteristics is always a research focus in Si-based device development and optimization. In this work, we report individual and dual gate-controlled energy band regulations of 30 nm-thick Si membrane and the resulted electron transportations at 10–300 K. It is discovered that the fine energy band structure is a key element to determine electron transport behaviors in fully-depleted silicon-on-insulator. Furthermore, either the front or the back gate bias can modify the energy band bending and sub-band gap, change charged body distribution and intersub-band transition probability, and thus adjust electron mobility and device performance. This dual gate coupling effect together with the proposed gate-controlled sub-band structure model is confirmed by magnetotransport experiments at 1.6 K. Notably, our work presents the coupled gate controlling effects within ultrathin Si film, and gives a physical insight into electron structure modulating, which may promote the evolution of Si-based device applications in many domains.
Deformation dependence of 2p-radioactivity half-lives: probe with a new formula across the mass region with Z < 82
Authors: Saxena G , Aggarwal Mamta , Singh D , Jain A , Sharma P K , Yadav H L 
Published: October 2022

Abstract
Effect of deformation on half-life of two-proton (2p) radioactivity is investigated across the periodic chart for nuclei with Z < 82. 2p-decay half-lives are estimated by employing our newly proposed semi-empirical formula wherein the nuclear deformation has been incorporated in a phenomenological way. Robustness of the formula is demonstrated as it estimates the measured values quite accurately and, hence, reliably applied to predict the other possible 2p-emitters. For many proton rich nuclei for which experimental data on the decay energies are not available, we have used the theoretical values obtained from our calculations using the relativistic mean-field approach. The uncertainties in the theoretical decay energy values are minimised by machine learning technique. Correlation of 2p-radioactivity with 2p-halo and deformation is probed. Our calculations show the phenomenon of shape coexistence in several 2p-emitters, wherein the prolate shape is found to be more predominant for the ground state.
Topological defects in Haldane model and higher Chern numbers in monolayer graphene
Authors: Chang Zhi-Wen , Hao Wei-Chang , Liu Xin 
Published: October 2022

Abstract
We consider the Haldane model, a two-band model in monolayer graphene with non-trivial Chern numbers. Two types of topological defects, monopoles and merons, are derived from the model: (a) the monopole defects occur at the Dirac points, where the system experiences a topological transition and the Chern number C takes an indeterminate value. The sign-change of the mass term after this transition indicates different topological states labeled by different C numbers; (b) the meron defects occur as per a varying mass term. Summing up the topological charges of the merons leads to the C evaluation for the energy bands of an insulating bulk, and the result we obtain is in full agreement to the past literature. Furthermore, in this paper we propose a high-C model through studying the limitation behavior of the Hamiltonian vector in the neighborhood of the topological defects. It is discovered that two conducting states may arise form the edges, where the lower band of the insulating bulk carries a higher Chern number,

C
=
±
2

.
An effective self-collision detection algorithm for multi-degree-of-freedom manipulator
Authors: Liu Zhenyu , Zhang Lianhao , Qin Xiaohong , Li Gang 
Published: October 2022

Abstract
In order to address the self-collision problem associated with the operation of modern industrial robots, this paper proposes a multi-degree-of-freedom collision detection algorithm that can detect self-collision in single arm and double arm robots as well as collision with the load. Firstly, the zero pose of the Denaviti−Hartenberg model is built based on the manipulator configuration, and the coordinate information of each key point is obtained through a rotation and translation operation of the matrix. Then, the positional relation and distance between the detected objects are determined by the spatial geometry theory, and finally, collision is detected using a collision matrix. By simulating two groups of single arms and two groups of double arms, and from the laboratory testing of SR10C in the SIASUN robot factory, it has been verified that the proposed algorithm has good collision detection capability. Without the use of sensors, cameras, and other external devices, the collision between the arm and the load, and the collision between the cooperative robot and the load may be effectively detected and mitigated.
Assessment of incident power density in different shapes of averaging area for radio-frequency exposure above 6 GHz
Authors: Morimoto Ryota , Hirata Akimasa 
Published: October 2022

Abstract

Objective. The International Commission on Non-Ionizing Radiation Protection guidelines and IEEE C95.1-2019 standard for human protection from local electromagnetic field exposure above 6 GHz state that absorbed (or epithelial) power density (APD) and incident power density (IPD), averaged over a square area, are internal and external physical quantities, respectively, that set the exposure limit. Per exposure standards, the measurement procedure and evaluation of the IPD have been established in technical standards, where a circular averaging area is recommended only for non-planar surfaces in IEC/IEEE 63195-1 and -2. In this study, the effects of two averaging shapes on the APD and IPD are evaluated computationally to provide new insights from the viewpoint of exposure standards. Approach. The relation between the APD, IPD, and the steady-state temperature rise (heating factor) in rectangular and human models for exposure to a single dipole, dipole arrays, and the Gaussian beams is investigated computationally with finite-difference method. Main results. The maximum differences in the heating factor of the APD and IPD for square and circular averaging areas were 4.1% and 4.4% for the antenna–model distance >5 mm, respectively. These differences appear when the beam pattern on the model surface has an elliptical shape. For an antenna–model distance ≤5 mm and at frequencies ≤15 GHz, the heating factors for square averaging areas were not always conservative to those for circular ones (−7.8% for IPD), where only the antenna feed point are visible before beam formation. Significance. The heating factors of the APD and IPD for a circular averaging area are conservative for near-field exposure of canonical sources for frequencies up to 300 GHz, except for a beam with a significant major-to-minor axis ratio and an angle of 30°–60° to a square averaging area. This tendency would help bridge the gap between exposure and product standards.
A clinically relevant online patient QA solution with daily CT scans and EPID-based in vivo dosimetry: a feasibility study on rectal cancer
Authors: Chen Liyuan , Zhang Zhiyuan , Yu Lei , Peng Jiyou , Feng Bin , Zhao Jun , Liu Yanfang , Xia Fan , Zhang Zhen , Hu Weigang , Wang Jiazhou 
Published: October 2022

Abstract

Objective. Adaptive radiation therapy (ART) could protect organs at risk (OARs) while maintain high dose coverage to targets. However, there is still a lack of efficient online patient quality assurance (QA) methods, which is an obstacle to large-scale adoption of ART. We aim to develop a clinically relevant online patient QA solution for ART using daily CT scans and EPID-based in vivo dosimetry. Approach. Ten patients with rectal cancer at our center were included. Patients’ daily CT scans and portal images were collected to generate reconstructed 3D dose distributions. Contours of targets and OARs were recontoured on these daily CT scans by a clinician or an auto-segmentation algorithm, then dose-volume indices were calculated, and the percent deviation of these indices to their original plans were determined. This deviation was regarded as the metric for clinically relevant patient QA. The tolerance level was obtained using a 95% confidence interval of the QA metric distribution. These deviations could be further divided into anatomically relevant or delivery relevant indicators for error source analysis. Finally, our QA solution was validated on an additional six clinical patients. Main results. In rectal cancer, the 95% confidence intervals of the QA metric for PTV ΔD
95 (%) were [−3.11%, 2.35%], and for PTV ΔD
2 (%) were [−0.78%, 3.23%]. In validation, 68% for PTV ΔD
95 (%), and 79% for PTV ΔD
2 (%) of the 28 fractions are within tolerances of the QA metrics. one patient’s dosimetric impact of anatomical variations during treatment were observed through the source of error analysis. Significance. The online patient QA solution using daily CT scans and EPID-based in vivo dosimetry is clinically feasible. Source of error analysis has the potential for distinguishing sources of error and guiding ART for future treatments.
Advances in Magnum-PSI probe diagnosis in support of plasma–surface interaction studies
Authors: Costin C , Mihaila I , van der Meiden H J , Scholten J , van Eck H J N , Vernimmen J W M 
Published: October 2022

Abstract
Magnum-PSI is a linear plasma generator equipped with a superconducting magnet, assuring fusion devices relevant conditions at plasma–surface interface. The plasma column was diagnosed using 64 probes embedded in the target. The cross-sectional distributions of plasma parameters (floating potential, ion saturation current and electron temperature) were measured for hydrogen and deuterium plasmas under various discharge conditions. The radial profile of the floating potential across the plasma column can be described by a reversed Mexican hat-like wavelet, having the most negative potential at the center of the plasma column. The negativity of the floating potential diminishes when the discharge current increases or the magnetic field decreases. The axial gradient of the floating potential is reduced by increasing the magnetic field. The ion saturation current is maximum at the center of the plasma column, increasing with both the discharge current and magnetic field. The ion flux to the target, estimated from Thomson scattering (TS) data, was confirmed by probe measurements. The electron temperature estimated from the ion branch of the probe current–voltage characteristic is few times larger than that obtained from TS. By increasing the gas pressure in the target chamber, the time-dependent ion saturation current measured by probes changes from a constant average current (when the plasma column is attached to the target) to a fluctuating average current with scattered peaks (in a partially detached regime) which vanishes completely in the fully detached regime. With respect to hydrogen, the plasma column is wider in deuterium and is characterized by less negative floating potential distributions.
Design and performance research on the actuator of high-speed valve based on shear working mode of magnetorheological fluid
Authors: Dai Jin , Yang Chenghao , Feng Xiangyu , Xiong Shaoping 
Published: October 2022

Abstract
The high-speed valve with advanced performance, which is expected to possess characteristics of large nominal flow and fast response at the same time, plays an important role in enabling efficient digital hydraulics. In order to solve the tradeoff between a large rated flow and less response time, this paper proposed a novel design of high-speed valve actuator called energy coupler actuator (ECA) based on the shear working mode of magnetorheological fluid. The ECA allows a rotary energy source couple/decouple the translational valve spool for fast and long stroke on/off switching. This work developed a multi-physics model of ECA to study its performance and simulation work based on response surface method has been conducted to optimize the ECA design parameters. An ECA prototype with the optimal design solution has been manufactured and experimentally tested. The testing results shows that driven by the power level similar to off-the-shelf solenoid valves, this ECA prototype only took 5 ms to achieve 1.5 mm stroke, which provide a flow area equivalent to a nominal flow of 100 l min−1@5 bar. This prototype also demonstrated the ECA’s design feature of long stroke with quick response by achieving 7 mm stroke in just 16 ms.
Cosmic perturbations from a rotating field
Authors: Co Raymond T. , Harigaya Keisuke , Pierce Aaron 
Published: October 2022

Abstract
Complex scalar fields charged under approximate U(1) symmetries appear in well-motivated extensions of the Standard Model. One example is the field that contains the QCD axion field associated with the Peccei-Quinn symmetry; others include flat directions in supersymmetric theories with baryon, lepton, or flavor charges. These fields may take on large values and rotate in field space in the early universe. The relevant approximate U(1) symmetry ensures that the angular direction of the complex field is light during inflation and that the rotation is thermodynamically stable and is long-lived. These properties allow rotating complex scalar fields to naturally serve as curvatons and explain the observed perturbations of the universe. The scenario imprints non-Gaussianity in the curvature perturbations, likely at a level detectable in future large scale structure observations. The rotation can also explain the baryon asymmetry of the universe without producing excessive isocurvature perturbations.
Dynamical adaptation in photoreceptors with gain control
Authors: Castillo García Miguel , Urdapilleta Eugenio 
Published: October 2022

Abstract
The retina hosts all processes needed to convert external visual stimuli into a neural code. Light phototransduction and its conversion into an electrical signal involve biochemical cascades, ionic regulations, and different kinds of coupling, among other relevant processes. These create a nonlinear processing scheme and light-dependent adaptive responses. The dynamical adaptation model formulated in recent years is an excellent phenomenological candidate to resume all these phenomena into a single feedforward processing scheme. In this work, we analyze this description in highly nonlinear conditions and find that responses do not match those resulting from a very detailed microscopic model, developed to reproduce electrophysiological recordings on horizontal cells. When a delayed light-dependent gain factor incorporates into the description, responses are in excellent agreement, even when spanning several orders of magnitude in light intensity, contrast, and duration, for simple and complex stimuli. This extended model may be instrumental for studies of the retinal function, enabling the linking of the microscopic domain to the understanding of signal processing properties, and further incorporated in spatially extended retinal networks.
Investigating pair-production by Breit–Wheeler process in a collisional plasma
Authors: Malik Hitendra K , Punia Sheetal 
Published: October 2022

Abstract
Positrons have many potential applications in the field of high-energy nuclear and particle physics. For the generation of such high-energy positrons, we propose a mechanism via an interaction of optical vortex laser beams with collisional plasma. Based on the multiphoton Breit–Wheeler mechanism, the production of electron–positron pairs shows to be strongly dependent on the energy associated with the synchrotron radiation. Such radiations are emitted by accelerated charged particles in the plasma channel under quasistatic spontaneous magnetic field that confines the motion of the electrons. For the precise regulation of the accelerated positrons important quantities such as the probabilistic generation of positrons and the angular momentum of the plasma electrons are evaluated and discussed. It is observed that the use of the incident Laguerre–Gaussian laser beam helps to generate on-axis sheath formation to focus and accelerate the produced positrons.
Laser-assisted CP-odd and CP-even Higgs bosons production in THDM
Authors: Ouhammou M , Ouali M , Taj S , Benbrik R , Manaut B , Hrour E 
Published: October 2022

Abstract
In this paper, we have theoretically studied the neutral Higgs pair production in Two Higgs Doublet Model (THDM) in the presence of a circularly polarized laser field. The laser-assisted differential partial cross section is derived in the centre of mass frame at the leading order including Z diagram. The total cross section is computed numerically by integrating the differential cross section over the solid angle

d
Ω

. Two benchmark points are discussed for the THDM parameters. In the first step, we have analysed the total cross section of

e

+

e

−

→

h

0

A

0

by considering H
0 as the standard model (SM)-like Higgs boson. Then, the process

e

+

e

−

→

H

0

A

0

is studied by taking h
0 as the Higgs boson of the SM. For both benchmark points, the laser-assisted total cross section of the studied processes depends on the produced neutral Higgs masses, the centre of mass energy and the laser field parameters. In addition, the maximum cross section occurs at high centre of mass energy for the process

e

+

e

−

→

H

0

A

0

as compared to that of

e

+

e

−

→

h

0

A

0

.