bluuebunny/crossref_metadata_2025_split huggingface dataset:
Twisted electron impact single ionization coincidence cross-sections for noble gas atoms
Authors: Dhankhar Nikita , Banerjee Soham , Choubisa R 
Published: June 2022

Abstract
We present the angular profiles of the triple differential cross-section (TDCS) for the (e, 2e) process on the noble gas atoms, namely He (1s), Ne (2s and 2p), and Ar (3p), for the plane wave and the twisted electron impact. We develop the theoretical formalism in the first Born approximation (FBA). The present study compares the TDCS for different values of orbital angular momentum number m and opening angles θ

p
of the twisted electron beam with that of the plane wave beam in co-planar asymmetric geometry. In addition, we also investigate the TDCS for macroscopic targets to explore the influence of the opening angle θ

p
of the twisted electron beam on the TDCS. Our results show that the peaks in binary and recoil regions shift from the momentum transfer direction. The results also show that for larger opening angles, the peaks for p-type orbitals split into double-peak structures, which are not observed in the plane wave results for the given kinematics. The angular profiles for averaged cross-section show the dependence of TDCS on the opening angles, especially for the larger opening angles, which are significantly different from the plane wave TDCS.
X-ray absorption of molecular cations—a new challenge for electronic structure theory
Authors: Carravetta V , Couto R C , Ågren H 
Published: June 2022

Abstract
In this paper we put forward some historical notes on the development of computational chemistry toward applications of x-ray spectroscopies. We highlight some of the important contributions by Enrico Clementi as method and program developer and as a supporter of this branch of computational research. We bring up a modern example based on the very recent experimental development of x-ray absorption of cationic molecules. As we show this spectroscopy poses new challenges for electronic structure theory and the electron correlation problem.
Magnetoquantum oscillations in the specific heat of a topological Kondo insulator
Authors: LaBarre P G , Rydh A , Palmer-Fortune J , Frothingham J A , Hannahs S T , Ramirez A P , Fortune N A 
Published: June 2022

Abstract
Surprisingly, magnetoquantum oscillations (MQOs) characteristic of a metal with a Fermi surface have been observed in measurements of the topological Kondo insulator SmB6. As these MQO have only been observed in measurements of magnetic torque (dHvA) and not in measurements of magnetoresistance (SdH), a debate has arisen as to whether the MQO are an extrinsic effect arising from rare-earth impurities, defects, and/or aluminum inclusions or an intrinsic effect revealing the existence of charge-neutral excitations. We report here the first observation of MQO in the low-temperature specific heat of SmB6. The observed frequencies and their angular dependence for these flux-grown samples are consistent with previous results based on magnetic torque for SmB6 but the inferred effective masses are significantly larger than previously reported. Such oscillations can only be observed if the MQO are of bulk thermodynamic origin; the measured magnetic-field dependent oscillation amplitude and effective mass allow us to rule out suggestions of an extrinsic, aluminum inclusion-based origin for the MQO.
Computational analysis of the enhancement of photoelectrolysis using transition metal dichalcogenide heterostructures
Authors: Baker Edward A D , Pitfield Joe , Price Conor J , Hepplestone Steven P 
Published: June 2022

Abstract
Finding a material with all the desired properties for a photocatalytic water splitter is a challenge yet to be overcome, requiring both a surface with ideal energetics for all steps in the hydrogen and oxygen evolution reactions (HER and OER) and a bulk band gap large enough to mediate said steps. We have instead examined separating these challenges by investigating the energetic properties of two-dimensional transition metal dichalcogenides (TMDCs) that could be used as a surface coating to a material with a large enough bulk band gap. First we investigated the energetics of monolayer MoS2 and PdSe2 using density functional theory and then investigated how these energetics changed when they were combined into a heterostructure. Our results show that the surface properties were practically (

<

0.2 eV) unchanged when combined and the MoS2 layer aligns well with the OER and HER. This work highlights the potential of TMDC monolayers as surface coatings for bulk materials that have sufficient band gaps for photocatalytic applications.
Reflectionless Klein tunneling of Dirac fermions: comparison of split-operator and staggered-lattice discretization of the Dirac equation
Authors: Donís Vela A , Lemut G , Pacholski M J , Tworzydło J , Beenakker C W J 
Published: June 2022

AbstractMassless Dirac fermions in an electric field propagate along the field lines without backscattering, due to the combination of spin-momentum locking and spin conservation. This phenomenon, known as ‘Klein tunneling’, may be lost if the Dirac equation is discretized in space and time, because of scattering between multiple Dirac cones in the Brillouin zone. To avoid this, a staggered space-time lattice discretization has been developed in the literature, withonesingle Dirac cone in the Brillouin zone of the original square lattice. Here we show that the staggering doubles the size of the Brillouin zone, which actually containstwoDirac cones. We find that this fermion doubling causes a spurious breakdown of Klein tunneling, which can be avoided by an alternative single-cone discretization scheme based on a split-operator approach.
Electron-impact ionization cross sections of small molecules containing Fe and Cr
∗
Authors: Romero José , Limão-Vieira Paulo , Probst Michael 
Published: June 2022

Abstract
We present the electron-impact ionization cross sections (EICSs) of iron and chromium hydrides, nitrides, and oxides. The motivation of this work stems from the fact that chemical sputtering from a steel surface exposed to a hot plasma can create these molecules which in turn influence the composition and energy balance of the plasma. The latter influence is quantified by the EICS which we derive by using two semi-empirical methods which can be employed in the relevant energy range of 10–1000 eV. They are important molecular properties for plasma- and materials science. We discuss the foundations of the methods and present the cross sections of the high- and low-spin states of the species in their neutral ground states and of their cations.
Explainable 1DCNN with demodulated frequency features method for fault diagnosis of rolling bearing under time-varying speed conditions
Authors: Lu Feiyu , Tong Qingbin , Feng Ziwei , Wan Qingzhu , an Guoping , Li Yilei , Wang Meng , Cao Junci , Guo Tao 
Published: June 2022

Abstract
Intelligent fault diagnosis of rolling bearings under non-stationary and time-varying speed conditions is still a challenging task. At the same time, a reasonable explanation for an intelligent diagnosis model based on features is currently lacking. Therefore, we exploit an explainable one-dimensional convolutional neural network (1DCNN) model by combining with the demodulated frequency features of vibration signals and apply it to the fault classification of rolling bearings under time-varying speed conditions. First, the speed signals obtained by the speed encoder were transformed into generalized demodulation operator (GDO). Second, combined with the sensitive frequency band and GDO, the generalized demodulation algorithm was used to extract the frequency features from the amplitude envelope of the vibration signal. Subsequently, the proposed lightweight 1DCNN was trained to classify the frequency features and identify the health states of the rolling bearing. Finally, the local interpretable model-agnostic explanations model was utilized to explain the proposed model based on the features which own weight. It is found that the internal classification mechanism of the lightweight 1DCNN is realized according to the distribution of fault features, which is consistent with the process of human brain analysis. Two kinds of time-varying speed datasets which come from the University of Ottawa and XJTU are tested and verified. The results show that compared with other intelligent fault diagnosis methods, the identification error of the proposed method is lower and the diagnosis stability is better. The average diagnostic accuracy was 96.26% and 99.82%, respectively.
Precision profile measurement of disc surface by error motion compensation
Authors: Hwang In-Oh , Seo Se-Min , Cho Nahm-Gyoo 
Published: June 2022

Abstract
In this study, a precision measurement method to obtain the surface profile of a rotating disc is proposed. To improve the accuracy of the estimated profile, the 3-DOF error motion included in the measured surface profile signal is simultaneously estimated and compensated. The profile of the disc is measured using a surface measuring unit equipped with one displacement sensor, and the error motion of the rotating component is measured using an error motion measuring unit equipped with a four-probe system. The developed error motion measuring unit uses a four-probe error separation technique, and the effect of zero setting errors between the probes on the compensated surface profile is analyzed. Subsequently, a process to remove the effect is proposed. To confirm the performance of the proposed method, numerical verification tests and experiments are performed using test equipment. The numerical verification tests show that the developed measuring system affords accurate shape estimation and is not affected by zero setting errors between probes. The experimental results of surface profile measurement using the proposed measurement method and the conventional one probe method are compared. The standard deviation of the measuring results using the proposed method was smaller than that of the conventional method by less than two-thirds. From this, it can be concluded that the error motions have been effectively compensated.
Fault feature analysis and detection of progressive localized gear tooth pitting and spalling
Authors: Luo Yang , Wang Hao , Shi Juanjuan , Yang Shuai , Baddour Natalie , Liang Ming 
Published: June 2022

Abstract
Fault feature analysis of gear tooth spalling plays a vital role in gear fault diagnosis. Understanding how fault features evolve as a fault progresses is key to fault severity assessment. Due to the complicated nature of gear meshing, fault features and their development as the fault severity progresses remain mostly unknown. The assessment of fault severity is generally based on the hypothesis that ‘the more severe the fault, the stronger the fault symptom’, an assumption that has not been experimentally validated. This paper provides a comprehensive, experimental analysis of the evolution of fault vibration features of a gear transmission with progressive localized gear tooth spalling. The effects of rotational speed on the vibration features of the gear transmission are analysed. Changes in fault features (e.g. periodic impulses and sideband phenomena) under different fault severity levels and speed conditions are compared. Results indicate that the number, amplitude and distribution of sidebands increase nonlinearly as the fault progresses. Based on feature analysis, a new health indicator of the mean of the nth order peaks is proposed to detect progressive localized tooth spalling. Results indicate that the proposed indicator shows very good performance for tracking the severity of progressive tooth spalling under different speed conditions.
An enhanced high frequency performance SiC MOSFET with self-adjusting P-shield region potential
Authors: Xing Yunpeng , Deng Xiaochuan , Wu Hao , Xu Xiaojie , Li Xu , Li Xuan , Wen Yi 
Published: June 2022

Abstract
An enhanced high frequency (HF) performance SiC metal oxide semiconductor field effect transistor (MOSFET) with self-adjusting P-shield region potential (SA-MOS) is proposed and characterized in this paper. The potential of P-shield region (ground or floating potential) can be adjusted by a depletion P-channel metal oxide semiconductor field effect transistor (PMOS) structure integrated in the SA-MOS. During turn-on of SA-MOS, the channel of integrated PMOS is pinched off and the P-shield region can be at a floating potential. Therefore, SA-MOS shows about 21% specific on-resistance (R
on,sp) reduction as compared to the conventional trench gate SiC MOSFET with grounded P-shield (GP-MOS) due to the retraction of depletion layer in drift region. During turn-off of SA-MOS, the integrated PMOS is turned on and the P-shield region is grounded to the source contact. Thus, the high on-state oxide electric field and slower switching speed caused by the floating P-shield region could be eliminated by SA-MOS structure. Furthermore, the gate-to-drain charge (Q
gd) of SA-MOS is only 217 nC cm−2 owing to smaller overlap area between drift region and trench gate, which is about 40% lower than that of GP-MOS. The HF figures of merit (HF-FOM= R
on,sp × Q
gd) for SA-MOS can be as low as 50% or more of GP-MOS. Finally, an analytical model is also developed to describe the variation of P-shield potential in SA-MOS. With the overall improved performance, SA-MOS shows a significant advantage in HF field in comparison with the GP-MOS.
Fluorine-containing organic ammonium salt-doped inverted inorganic perovskite solar cells
Authors: Shi Kewang , Zhang Fanghui , Zhang Meng , Chen Chunyang , Zhang Wenxi , Huang Jin 
Published: June 2022

Abstract
Inorganic lead halide perovskites have a reasonable energy bandgap, which makes them ideal for tandem devices. As a result, inorganic lead halide perovskite solar cells (PSCs) could be prospective next-generation solar materials, but the issue of instability under moisture remains unaddressed. Adding 4-fluoro-phenyl-ethylammonium iodide (F-PEAI) spacer cations to the perovskite precursor solution is an elementary addition method to improve the performance of PSCs. We study the impact of F-PEAI on the perovskite crystal phase and the effect of F-PEAI concentration on PSC performance. F-PEAI was used to passivate interfacial flaws and vacancies in inverted inorganic PSCs and improve moisture tolerance, resulting in a mixed 2D/3D heterostructure. A small number of F-PEAI-treated PSCs have changed interfacial characteristics, resulting in better charge extraction and less charge recombination. The power conversion efficiency (PCE) of the F-PEAI treated device is much higher than that of the control group, and the PCE is improved to more than 11%. To attain high efficiency, all-inorganic perovskites can be modified using a straightforward method.
Kinematics and shear-induced alignment in confined granular flows of elongated particles
Authors: Pol Antonio , Artoni Riccardo , Richard Patrick , Nunes da Conceição Paulo Ricardo , Gabrieli Fabio 
Published: June 2022

Abstract
The kinematics and the shear-induced alignment of elongated particles in confined, heterogeneous flow conditions are investigated experimentally. Experiments are conducted in an annular shear cell with a rotating bottom wall and a top wall permitting confinement of the flow. Flow kinematics and particle orientation statistics are computed by particle tracking using optical imaging. Translational velocity profiles show an exponential decay, and surprisingly, only the slip velocity at the bottom is influenced by the particle shape. Rotations are highly frustrated by particle shape, more elongated particles showing, on average, a lower angular velocity. In addition, a clear shear-rate dependency of the proneness of a particle to rotate is observed, with a stronger inhibition in low shear zones. The average orientation of the particles does not correspond to the main flow direction, they are slightly tilted downwards. The corresponding angle decreases with the particles’ elongation. Orientational order was observed to increase with particles’ elongation, and surprisingly was not affected by the applied confinement. A weak but systematic decrease of the orientational order was observed in regions of higher shear rate. At the particle-scale, angular velocity fluctuations show a strong correlation with local particle orientation, particles being strongly misaligned with the preferential particles’ orientation rotating faster. This correlation becomes stronger for more elongated particles, while is almost unaffected by the applied confinement.
Surface plasmon-driven electron and proton acceleration without grating coupling
Authors: Sarma J , McIlvenny A , Das N , Borghesi M , Macchi A 
Published: June 2022

Abstract
Surface plasmon (SP) excitation in intense laser interaction with solid target can be exploited for enhancing secondary emissions, in particular efficient acceleration of high charge electron bunches. Previous studies have mostly used grating coupling to allow SP excitation, which requires stringent laser contrast conditions to preserve the structural integrity of the target. Here we show via simulations that efficient SP electron acceleration for currently available short pulse lasers can occur in a flat foil irradiated at parallel or grazing incidence (

∼
5
°

with the target surface) without a surface modulation. In turn, the accelerated electrons can be effective for generating proton beams with narrow spectra peaked at

>

100 MeV energies for currently available laser drivers.
First and second sound in a dilute Bose gas across the BKT transition
Authors: Singh Vijay Pal , Mathey Ludwig 
Published: June 2022

Abstract
We study the propagation of the two sound modes in two-dimensional Bose gases across the Berezinksii–Kosterlitz–Thouless transition using classical-field dynamics, which is motivated by recent measurements of Christodoulou et al (2021 Nature
594 191). Based on the dynamic structure factor (DSF), we identify the two sound modes as the Bogoliubov (B) and the non-Bogoliubov (NB) sound mode below the transition, and as the diffusive and the normal sound mode above the transition. The NB sound mode velocity is higher than the B sound mode velocity, which we refer to as the weak-coupling regime of the sound modes. We excite the sound modes by driving the system as in the experiment and by perturbing the density with a step-pulse perturbation, as a secondary comparison. The driven response depends on the driving strength and results in higher velocities for the B sound mode at high temperatures near the transition, compared to the sound results of the DSF and step-pulse excitation. We show that the higher mode velocity has a weak temperature dependence across the transition, which is consistent with the experimental observation.
Geminga contribution to the cosmic-ray positron excess according to the gamma-ray observations
Authors: Zhou Guang-Yao , Yu Zhao-Huan , Yuan Qiang , Zhang Hong-Hao 
Published: June 2022

Abstract
We attempt to interpret the cosmic-ray positron excess by injection from the nearby pulsar Geminga, assuming a two-zone diffusion scenario and an injection spectrum with a low energy cutoff. Since the high energy positrons and electrons from Geminga can induce γ rays via inverse Compton scattering, we take into account the extended γ-ray observations around Geminga from HAWC for ∼10 TeV and from Fermi-LAT for


(
10
)

GeV. According to the extended γ-ray observation claimed by an analysis of Fermi-LAT data, we find that Geminga could explain the positron excess for a 30% energy conversion efficiency into positrons and electrons. However, based on the constraint on the extended γ rays given by another Fermi-LAT analysis, positrons from Geminga would be insufficient to account for the positron excess. Further robust analysis of Fermi-LAT data for the extended γ rays would be crucial to determine whether Geminga can explain the positron excess or not.
The ringing of quantum corrected Schwarzschild black hole with GUP
Authors: Xing Yujia , Yang Yi , Liu Dong , Long Zheng-Wen , Xu Zhaoyi 
Published: June 2022

Abstract
Schwarzschild black holes with quantum corrections are studied under scalar field perturbations and electromagnetic field perturbations to analyze the effect of the correction term on the potential function and quasinormal mode (QNM). In classical general relativity, spacetime is continuous and there is no existence of the so-called minimal length. The introduction of the correction items of the generalized uncertainty principle, the parameter β, can change the singularity structure of the black hole gauge and may lead to discretization in time and space. We apply the sixth-order WKB method to approximate the QNM of Schwarzschild black holes with quantum corrections and perform numerical analysis to derive the results of the method. Also, we find that the effective potential and QNM in scalar fields are larger than those in electromagnetic fields.
Searching for isotropic stochastic gravitational-wave background in the international pulsar timing array second data release
Authors: Chen Zu-Cheng , Wu Yu-Mei , Huang Qing-Guo 
Published: June 2022

Abstract
We search for isotropic stochastic gravitational-wave background (SGWB) in the International Pulsar Timing Array second data release. By modeling the SGWB as a power-law, we find very strong Bayesian evidence for a common-spectrum process, and further this process has scalar transverse (ST) correlations allowed in general metric theory of gravity as the Bayes factor in favor of the ST-correlated process versus the spatially uncorrelated common-spectrum process is 30 ± 2. The median and the 90% equal-tail amplitudes of ST mode are



ST

=

1.29

−
0.44

+
0.51

×

10

−
15

, or equivalently the energy density parameter per logarithm frequency is

Ω
GW
ST

=

2.31

−
1.30

+
2.19

×

10

−
9

, at frequency of 1 year−1. However, we do not find any statistically significant evidence for the tensor transverse (TT) mode and then place the 95% upper limits as



TT

<
3.95
×

10

−
15

, or equivalently

Ω
GW
TT

<
2.16
×

10

−
9

, at frequency of 1 year−1.
Underwater robot coordination using a bio-inspired electrocommunication system
Authors: Zhou Yang , Wang Wei , Zhang Han , Zheng Xingwen , Li Liang , Wang Chen , Xu Gang , Xie Guangming 
Published: June 2022

Abstract
Due to the challenging communication and control systems, few underwater multi-robot coordination systems are currently developed. In nature, weakly electric fish can organize their collective activities using electrocommunication in turbid water. Inspired by this communication mechanism, we developed an artificial electrocommunication system for underwater robots in our previous work. In this study, we coordinate a group of underwater robots using this bio-inspired electrocommunication. We first design a time division multiple access (TDMA) network protocol for electrocommunication to avoid communication conflicts during multi-robot coordination. Then, we revise a distributed controller to coordinate a group of underwater robots. The distributed controller on each robot generates the required controls based on adjacent states obtained through electrocommunication. A central pattern generator (CPG) controller is designed to adjust the speed of individuals according to distributed control law. Simulations and experimental results show that a group of underwater robots is able to achieve coordination with the developed electrocommunication and control systems.