bluuebunny/crossref_metadata_2025_split huggingface dataset:
Two pandemics: the COVID-19 pandemic’s impact on future AMR collaboration in Europe
Authors: Lampi Elina , Carelli Daniel , Pierre Jon , Rönnerstrand Björn 
Published: July 2023

AbstractBased on 117 responses to a web survey in 29 European countries and interviews with bureaucrats in managerial positions, this paper investigates how people working professionally with antimicrobial resistance (AMR) assess the impact of the COVID-19 pandemic on their future long-run cooperation in the struggle against AMR, both within their own country and among the European countries. We measure whether the severity level of the AMR problem, cumulative COVID-19 death rates, and the daily number of confirmed new COVID-19 cases in their own countries have affected bureaucrats’ beliefs about long-run AMR collaboration. We find that around 40% of the bureaucrats believe that the cooperation will increase domestically and at the European level, indicating that global health crises such as the COVID-19 pandemic can shape future collaboration across the European countries when it comes to the equally global but more long-run health problem, AMR. However, there are considerable differences across regions: Eastern European bureaucrats are clearly the most pessimistic about future cooperation, while the Southern European and Nordic bureaucrats are the most optimistic. Neither the severity of the AMR problem nor the number of confirmed new COVID-19 cases in their own countries has a significant impact on bureaucrats’ beliefs about future collaboration. Instead, it is the cumulative COVID-19 death rate that increases the perceived likelihood of future AMR collaboration, both domestically and among the European countries. Furthermore, our interviews highlight the longer-term impact of the pandemic on public health in the EU countries and the prospect of increased EU control to prevent future cross-border health hazards. The mixed methods approach details both the broader patterns of bureaucrats’ perceptions of the impact of the pandemic on AMR-related work as well as the more long-term institutional changes that are likely to follow in the wake of the pandemic.
Forevacuum plasma-cathode electron source for generation of a ribbon beam over a wide pressure range
Authors: Klimov A. S. , Bakeev I. Yu. , Burachevsky Yu. A. , Dagri J. E. , Oks E. M. , Zenin A. A. 
Published: July 2023

We describe the results of our investigations of the generation of a ribbon electron beam (10 × 220 mm2) by a two-stage discharge system based on a hollow-cathode glow discharge plasma. The source design enables operation in the pressure range 2 × 10−2 to 10 Pa. At a beam accelerating voltage of 8 kV, the beam current is 450 mA at a pressure of 2 × 10−2 Pa and 150 mA at a pressure of 10 Pa. To achieve a uniform current density distribution of the beam over its cross-sectional area, a special design of emission electrode was employed. This enabled us to reduce non-uniformities of the beam current density distribution to a level of 10%.
Shadows and photon rings of regular black holes and geonic horizonless compact objects
Authors: Olmo Gonzalo J , Rosa João Luís , Rubiera-Garcia Diego , Sáez-Chillón Gómez Diego 
Published: July 2023

Abstract
The optical appearance of a body compact enough to feature an unstable bound orbit, when surrounded by an accretion disk, is expected to be dominated by a luminous ring of radiation enclosing a central brightness depression typically known as the shadow. Despite observational limitations, the rough details of this picture have been now confirmed by the results of the Event Horizon Telescope (EHT) Collaboration on the imaging of the M87 and Milky Way supermassive central objects. However, the precise characterization of both features—ring and shadow—depends on the interaction between the background geometry and the accretion disk, thus being a fertile playground to test our theories on the nature of compact objects and the gravitational field itself in the strong-field regime. In this work we use both features in order to test a continuous family of solutions interpolating between regular black holes and horizonless compact objects, which arise within the Eddington-inspired Born–Infeld theory of gravity, a viable extension of Einstein’s general relativity (GR). To this end we consider seven distinctive classes of such configurations (five black holes and two traversable wormholes) and study their optical appearances under illumination by a geometrically and optically thin accretion disk, emitting monochromatically with three analytic intensity profiles previously suggested in the literature. We build such images and consider the sub-ring structure created by light rays crossing the disk more than once and existing on top of the main ring of radiation. We discuss in detail the modifications as compared to their GR counterparts, the Lyapunov exponents of unstable nearly-bound orbits, as well as the differences between black hole and traversable wormholes for the three intensity profiles. In addition we use the claim by the EHT Collaboration on the radius of the bright ring acting (under proper calibrations) as a proxy for the radius of the shadow itself to explore the parameter space of our solutions compatible with such a result.
Plasma behavior of a low current orificed hollow cathode using krypton propellant for electric thruster applications
Authors: Liu Wei , Hu Renjie , Wang Weizong , Li Yifei , Yan Jiaqi 
Published: July 2023

Abstract
As a fundamental component, hollow cathodes have been widely used in electric thruster applications. Krypton has become one of the ideal alternative propellants for hollow cathode due to its economy, thus it is vital to understand the basic physical process of the discharge of krypton-fed hollow cathode. This study sets out to establish a two-dimensional fluid model coupled with the equations for gas flow and heat transfer allowing to obtain a self-consistent description of the cathode discharge. The anomalous collision term based on the formulations of Sagdeev and Galeev is considered in this model. The model is validated by comparing the simulated and measured plasma characteristic parameters and reasonable agreement is reached. The findings show that the discharge of the krypton-fed hollow cathode is characterized by the lower plasma density, higher electron temperature, and higher spatial electric potential compared to that of the xenon-fed hollow cathode and tends to present a higher plasma density in the cathode plume region when it is operating with the diode configuration. The double layer formed at the keeper orifice is an important factor for the low electron temperature distribution, which is greatly affected by the keeper current. These findings add to our understanding of plasma behavior in the discharge of a low current krypton-fed hollow cathode and support further development of credible krypton-fed hollow cathode.
Nonreciprocal terahertz wavefront manipulation based on a magneto-optical metasurface with an orthogonal meta-atom pair
Authors: Wang Hao , Fan Fei , Tan Zhi-Yu , Zhao Dan , Cheng Jie-Rong , Chang Sheng-Jiang 
Published: July 2023

Abstract
Active wavefront manipulation and nonreciprocal transmission give key performances in beam steering, unidirectional isolation, and multichannel multiplexing. In this work, we propose a magneto-optical (MO) Pancharatnam–Berry (PB) metasurface, which consists of a pair of orthogonal anisotropic Si and InSb columns. This orthogonal meta-atom pair (OMP) structure leads to destructive interference in the geometric phase so that the wavefront manipulation is in the OFF state without a biased magnetic field (BMF). When the BMF is applied, the nonreciprocal transmission effect for different spin states in InSb breaks the original destructive interference, so the devices provide different geometric phase distribution for different magnetic field directions and spin states, achieving the ON state of the nonreciprocal wavefront manipulation, where cross-polarization circular dichroism is higher than 0.98 and the polarization conversion rate is over 97%. Furthermore, based on this mechanism, a beam deflector and a vortex beam generator are designed by arranging the OMP with different azimuthal angles. Compared with ordinary reciprocal wavefront manipulation, this work shows that this MO PB metasurface with OMP structure has irreplaceable functions in the isolation, selection, and conversion of the two conjugate spin beams, providing a unique path for active THz wavefront manipulation.
Plasmon resonance-enhanced superior 2D MoS2 photodetector via single-layer gold nanoparticle film with ultra-high area density
Authors: Wang Dou , Han Bin , Wang Guanghui , Liu Bo , Ma Shufang , Xu Bingshe , Li Guoqiang 
Published: July 2023

Abstract
Molybdenum disulfide (MoS2) has been considered as a promising candidate material for photodetectors due to its unrivaled transistor behavior and strong light absorption. However, due to the ultra-thin nature of monolayer or few-layer MoS2, it exhibits a low optical cross-section, resulting in a very weak light–matter interaction and accordingly limiting the photoelectric conversion efficiency. In this work, we report a facile method to prepare single-layer gold (Au) nanoparticles with ultra-high area density according to the annealing of thin Au films. By transferring the single-layer Au nanoparticle film onto a prefabricated MoS2 photodetector, we demonstrate a photodetector with a responsivity as high as 1120 A W−1. Moreover, it is found that the response time is not affected by the Au nanoparticle decoration. This method provides an easy but effective way to fabricate high-performance two-dimensional material-based photodetectors.
Blind extraction of acoustic signals from rolling bearing composite faults based on ISCA-IMCKD
Authors: Tang Jialu , Zhou Jun , Wu Xing , Liu Tao , Liu Xiaoqin 
Published: July 2023

Abstract
In production practice, the signal gathered by a sensor often includes strong ambient noise, and its composition is complex. Focusing on the problem that traditional methods are difficult to separate and extract fault frequencies from strong background noise, a novel compound fault blind extraction method based on improved sparse component analysis (ISCA) and improved maximum correlation kurtosis deconvolution (IMCKD)-named ISCA‐IMCKD- is suggested. Initially, the signal that the sensor has collected is shifted into time-frequency area signal by short-time Fourier transform (STFT). In addition, the single source domain characteristic data is screened by improved single source point detection to determine the number of sources. Second, the ISCA method is optimized by using cosine distance improved fuzzy C-means clustering, which is utilized to further process the characteristic data to calculate the mixing matrix. Moreover, the estimated source signal is initially extracted according to the membership degree of clustering results. Finally, the estimated source signal is shifted into the time area by inverse STFT transform, and the IMCKD is employed to enhance the characteristics of the projected source signals. Meanwhile, the initially estimated source signal is completely separated, and the defect frequencies of the composite faults are finally extracted by envelope analysis. Simulation experiments and measured data are employed to certify the viability of the proposed means. The defect detection of rolling bearings is finished while the time cost is significantly saved.
Soft sensor modeling of cement clinker quality: a novel timing matching technique and data decoupling approach
Authors: Zhao Yantao , Wu Ruteng , Zhang Shanshan , Qu Hong , Hao Xiaochen 
Published: July 2023

Abstract
Clinker free calcium oxide (f-CaO) content is an important indicator of cement quality. Considering the production characteristics (strong coupling, time-varying delay) in the cement process industry, a soft sensor model was developed by combining various methods. First, a new decoupling method is proposed to deal with the strong coupling between variables, which achieves data decoupling between process variables through the attention mechanism and the long short-term memory network. Second, a novel time-series matching technique is proposed to handle the time-varying delays, which utilizes a window selection mechanism to adaptively select the time period in which each process variable influences the target variable. Third, the critical features of the variables are extracted by a one-dimensional convolution network (1D-CNN). Last, a combination of the data decoupling method, window selection mechanism, and 1D-CNN is applied to develop a soft sensor model (ADM-WGM-CNN), which implements the measurement of f-CaO content. The experimental results demonstrate that the ADM-WGM-CNN model has better measurement performance.
InGaN/GaN superlattice underlayer for fabricating of red nanocolumn μ-LEDs with (10-11) plane InGaN/AlGaN MQWs
Authors: Yamada Jumpei , Mizuno Ai , Honda Tatsuya , Yoshida Keigo , Togashi Rie , Nomura Ichirou , Yamaguchi Tomohiro , Honda Tohru , Kishino Katsumi 
Published: July 2023

Abstract
In this study, the growth behavior of Indium gallium nitride (InGaN)-based nanocolumn arrays was investigated, and red emission nanocolumn micro-light emitting diodes (μ-LEDs) were fabricated. The internal structure of the InGaN/GaN superlattice (SL) layer under the multiple-quantum-well (MQW) active layers was evaluated using scanning transmission electron microscopy (STEM) analysis. It was revealed that the InGaN crystal plane at the top of the nanocolumn changed from the c-plane, (1-102) plane, to the (10-11) plane as the number of SL pairs increased. A semipolar (10-11) plane was completely formed on top of the nanocolumn by growing InGaN/GaN SLs over 15–20 pairs, where the InGaN/GaN SL layers were uniformly piled up, maintaining the (10-11) plane. Therefore, when InGaN/AlGaN MQWs were grown on the (10-11) plane InGaN/GaN SL layer, the growth of the (10-11) plane semipolar InGaN active layers was observed in the high-angle annular dark field (HAADF)-STEM image. Moreover, the acute nanocolumn top of the (10-11) plane of the InGaN/GaN SL underlayer did not contribute to the formation of the c-plane InGaN core region. Red nanocolumn μ-LEDs with an φ12 μm emission window were fabricated using the (10-11) plane MQWs to obtain the external quantum efficiency of 1.01% at 51 A cm−2. The process of nanocolumn μ-LEDs suitable for the smaller emission windows was provided, where the flat p-GaN contact layer contributed to forming a fine emission window of φ5 μm.
Impact on students’ problem-solving skills by making a magnetic safe box
Authors: Pazmino A , Mosquera J , Roblero J , Romero-Vera A , Gutiérrez E D 
Published: July 2023

Abstract
The physical principles of electromagnetism are hard for students to understand, even though they explain our surrounding world, including technology. Active learning methodologies play an important role in students’ learning processes of such concepts. Using project-based learning, with the appropriate project, students can be engaged in any science subject. This paper studies the impact of two striking real-life projects utilizing concepts related to different learning course objectives on students’ problem-solving skills through theoretical calculations of the projects before building the prototype.
Measuring the speed of sound with a pan flute and a smartphone: a half-melodic and totally-didactic experiment
Authors: Torcal-Milla Francisco Jose 
Published: July 2023

Abstract
Teaching wave-physics and related phenomena with musical instruments results in a very pleasant and didactic approach for undergraduate students. Music allows teaching concepts such as frequency, amplitude, harmonics, resonance, and so on. In addition, one may use some instruments to calculate other quantities such as the air density or the speed of sound in the air. In this work, we use a conventional bamboo-made panflute and a smartphone to obtain the speed of sound in the air. The method is simple. It consists of making the pipes sound and measuring the frequency of the fundamental harmonic. The frequency is approximately proportional to the inverse of the pipe length and this dependence allows us to obtain the speed of sound quite accurately from the slope of the curve. We compare it with the theoretical value and analyse three possible causes of discrepancy such as the end correction, the air composition, or the straightness of the tubes. The proposed experiment can be carried out completely by the students since it does not involve any danger. In addition, it could be appropriate for undergraduate students or even school students.
Effect of spatial-domain pulse width on the resolution of scattering images in ultrasound computed tomography
Authors: Zhang Qiude , Liu Quanquan , Liu Zhaohui , Ding Mingyue , Yuchi Ming 
Published: July 2023

Abstract
Full-aperture tomography (FAT) is the major image reconstruction method for a circular ring array (CRA)-based ultrasound computed tomography (USCT) system. The FAT technique requires transferring the reconstruction process from the temporal domain to the spatial domain, during which the imaging resolution of the USCT is degraded by the spatial-domain pulse width (SDPW) of backprojection areas. To tackle this challenge, this study investigates the characteristics of the SDPW and how it degrades the image resolution. We show that the SDPW depends on the frequency of the ultrasound and the position of the transmitting elements, receiving elements and the imaging point. To quantify the deterioration of image resolution associated with the position of the transmitting and receiving elements, a SDPW broadening factor (SDPWBF) is introduced. The results of numerical simulation show a smaller SDPWBF provides a better reflection image resolution, and the distribution of SDPWBF shows that a shorter distance between the receiving element and the transmitting element yields a smaller SDPWBF. The SDPWBF is therefore able to be an indicator of selecting the signals acquired from the transmitting and receiving elements to perform optimal image resolution. Single-scatterer phantom and in
vivo experiments demonstrate how the SDPWBF affects the USCT image spatial resolution and signal-to-noise ratio (SNR), and the results agree well with the theoretical predictions.
A reaction mechanism for oxygen plasmas
Authors: Dias Tiago C , Fromentin Chloé , Alves Luís L , Tejero-del-Caz Antonio , Silva Tiago , Guerra Vasco 
Published: July 2023

Abstract
This work presents a reaction mechanism for oxygen plasmas, i.e. a set of reactions and corresponding rate coefficients that are validated against benchmark experiments. The kinetic scheme is validated in a DC glow discharge for gas pressures of 0.2–10 Torr and currents of 10–40 mA, using the 0D LisbOn KInetics simulation tool and available experimental data. The comparison comprises not only the densities of the main species in the discharge—

O
2

(

X

3

Δ

g

−

)

,

O
2

(

a
1

Δ

g

)

,

O
2

(

b
1

Σ

g
+

)

and

O

(
3

P
)

—but also the self-consistent calculation of the reduced electric field and the gas temperature. The main processes involved in the creation and destruction of these species are identified. Moreover, the results show that the oxygen atoms play a dominant role in gas heating, via recombination at the wall and quenching of

O
2

(

X

3

Σ

g
−

,
v

)

vibrations and

O
2

electronically-excited states. It is argued that the development and validation of kinetic schemes for plasma chemistry should adopt a paradigm based on the comparison against standard validation tests, as it is done in electron swarm validation of cross sections.
Changing pattern of N2 dissociation in N2–Ar RF plasma during E–H mode transition
Authors: Mukherjee A , Chakraborty M , Sharma N , Saha P K 
Published: July 2023

Abstract
The behaviour of nitrogen plasma mixed with varying proportions of argon (10%–80%) is investigated under different RF discharge conditions. It is observed that at a relatively low RF power of 200 W (E-mode) the dissociation fraction (DF) of nitrogen increases with the growing concentration of argon, whereas the opposite happens for a higher RF power of 1000 W (H-mode), when the DF rapidly falls from a high value as the argon percentage starts to increase. This rising trend of DF closely follows the argon metastable fraction (MF) in the E-mode, and for the H-mode it is not followed until the argon percentage crosses the 20% mark. The electron density, temperature and electron energy probability function (EEPF) are obtained using a RF compensated Langmuir probe and to evaluate the vibrational and rotational temperatures, DF, MF etc, a separate optical emission spectroscopy technique is incorporated. At 5 × 10−3 mbar of working pressure and 10% argon content the EEPF profile reveals that the plasma changes from non-Maxwellian to Maxwellian as the RF power jumps from 200 W to 1000 W, and for a fixed RF power the high energy tail tends to move upwards with the gradual increment of argon. These observations are reverified theoretically by considering electron–electron collision frequency and electron bounce frequency as a function of electron temperature. Overall, all the major experimental phenomena in this study are explained in terms of EEPF profile, electron–electron collision effect, electron and gas temperature, electron density and argon metastable population.
A three-stage amplification piezoelectric-actuated micro-gripper with adjustable output displacement: design, modeling, and experimental evaluation
Authors: Xu Dongmei , Yang Fan , Yu Simiao , Xu Chao , Liu Xianglong , Zhao Zhiwei , Zhang Xuhui , Li Shuaitian , Yang Huixi , Lu Qi 
Published: July 2023

Abstract
With the development of science and technology, the performance requirements of micro-gripper are getting higher and higher. Therefore, this paper designs a new piezoelectric-driven micro-gripper with large and adjustable output displacement, which can adjust the output range and compensate the errors caused by flexible mechanism. By adjusting the output displacement, the micro-components of different sizes can be clamped. The three-stage amplification mechanism is adopted, which utilizes triangle and lever amplification. Using the pseudo-rigid body method, the flexible hinge is analyzed; the statics, kinematics and dynamics models are established. Through finite element method, the magnification ratio of the micro-gripper is obtained, then the structure of the micro-gripper is further optimized. The output displacement and the magnification of the single-arm of the micro-gripper under 135 V are 223.8 μm and 24.2 times, respectively. This paper provides a basis for the wide application of micro-gripper.
Photoelectric transport signals induced by the periodical B/P substitution of doped graphene half-metals
Authors: Zuo Xueying , Cheng Jingjing , Liang Yulin , Xu Fuming , Xing Yanxia 
Published: July 2023

Abstract
Using the nonequilibrium Green’s function combined with the density functional theory, we investigate the spin-resolved photoelectric current in ferromagnetic hydrogenated zigzag graphene nanoribbons with boron or phosphorus atom substitutions (B/P-ZGNRs). Our findings indicate that B/P substitution induces half-metallic or semiconducting characteristics, depending on the edge form and substituted atoms. Induced by linear polarized light, the spin-resolved photocurrent could reveal information of the band structure and the contribution of different orbitals to the transport processes. Photocurrent peaks at specific photon energies clearly indicate the band edge of B/P-ZGNRs, while its signs reflect the distribution of the transmission coefficient spectrum. In symmetrically hydrogenated B/P-ZGNRs, the px
orbital is found to be dominant. However, in asymmetric B/P-ZGNRs, the py
orbital can also be dominant. Furthermore, B/P substitution induces a narrow band near the Fermi level, leading to remarkable negative differential resistance. These findings suggest potential applications of B/P-ZGNRs in spintronic devices and micro photoelectric detection.