bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of the twin boundary and Cr segregation on the spalling of Ni-base alloys by large-scale molecular dynamic simulations
Authors: Zhu Huanwen , Wang Kun , Xiao Shifang , Li Xiaofan , Hu Wangyu
Published: April 2023

Large-scale nonequilibrium molecular dynamics simulation is used to study the effect of grain size and Cr segregation at the twin boundary (TB) on the spalling fracture mechanism of nickel based alloys. In particular, loading waves are designed so that the maximum tensile stress first appears in the grain interior for all the crystals with different grain sizes. In contrast to traditional understandings, no monotonous relationship between the spall strength and the grain size appears in our results. The spall strength is found to depend on the wave attenuation distance measured from the first maximum tensile stress position to the spalled TB as well as the accompanied microstructure evolutions. The number of spalling plane increases with the increase of TB or the decrease of the grain size. As the grain size continues to decrease, a greater impact strength is required to cause spallation fracture at multiple TBs. In this case, the spall strength becomes insensitive to the first maximum tensile stress position. With the increment of solute atom concentration, the number of the spalling plane increases when the solution is segregated. But it decreases when the solution is uniformly distributed. Such a result is explained by segregation-enhanced energy dissipation and interactions between the waves and the microstructures nearby TBs. In particular, the shock wave would induce a local lattice reorientation nearby the TB depending on its segregation degree and the lattice reorientation would modify the slip manner of stacking faults and, thus, affect void nucleation and growth. The lattice reorientation would also contribute to the generation of sub-grain boundaries inside the grains in terms of the movement of stacking faults. Void nucleation at the sub-GB is the main cause of fracture at the grain interior.
Current-driven magnetic skyrmion diodes controlled by voltage gates in synthetic antiferromagnets
Authors: Xu Min , Zhang Zhiyu , Zhang Jinyu , Jiang Guiqian , Chen Yuliang , Chen Wenlong , Hu Changjing
Published: April 2023

Magnetic skyrmions, as promising candidates in various spintronic devices, have been widely studied owing to their particle-like properties, nanoscale size, and low driving current density. Here, we numerically and theoretically investigate the dynamics of current-driven skyrmion passing through a voltage gate in a synthetic antiferromagnetic racetrack. It is found that the critical current required for skyrmion to pass through the voltage gate positively is much less than that for skyrmion to pass through the gate negatively. Furthermore, we systematically study the linear dependence of the minimum velocity of skyrmion on the driving current density and perpendicular magnetic anisotropy (PMA) gradient, and the calculation results are quite consistent with the simulation results. Finally, we find that the variation of the PMA energy with the position of skyrmion can help us to compare the magnitude of resistance force when the skyrmion passes through different voltage gates. Our results can be beneficial for the design and development of skyrmion diodes.
Electron impact ionization cross sections of highly charged open L-shell tungsten ions
Authors: He Zhencen , Niu Ben , Xiong Gang , Huang Liangyu , Liu Jialin , Liu Liang , Hu Zhimin , Chen Chongyang , Wei Baoren , Zou Yaming , Yao Ke
Published: April 2023

L-shell electron-impact ionization (EII) cross sections for highly charged tungsten ions were measured at incident electron energies of 29.10 and 38.92 keV using the Shanghai-EBIT. Resolved x-rays from radiative recombination (RR) processes were recorded with a high-purity Ge detector in a static electron energy scanning mode. Absolute EII cross sections were obtained by normalizing to the theoretical RR cross sections. The experimental results were compared with the calculated results using the relativistic distorted-wave method implemented in the flexible atomic code and the relativistic Lotz semi-empirical equation. The measurements showed general agreement with the calculated results by two theoretical methods for Li- to N-like W ions. The experimental uncertainties are not sufficiently small to discern the two theoretical results. Furthermore, the influence of Breit interaction on the EII cross sections of open L-shell tungsten ions was studied, and the effect is small but non-negligible. The measured EII cross sections of open L-shell tungsten ions would contribute to fusion plasma studies.
Non-equilibrium dynamics at the gas–liquid interface: State-resolved studies of NO evaporation from a benzyl alcohol liquid microjet
Authors: Ryazanov Mikhail , Nesbitt David J.
Published: April 2023

First measurements of internal quantum-state distributions for nitric oxide (NO) evaporating from liquid benzyl alcohol are presented over a broad range of temperatures, performed by liquid-microjet techniques in an essentially collision-free regime, with rotational/spin–orbit populations in the 2Π1/2,3/2 manifolds measured by laser-induced fluorescence. The observed rotational distributions exhibit highly linear (i.e., thermal) Boltzmann plots but notably reflect rotational temperatures (Trot) as much as 30 K lower than the liquid temperature (Tjet). A comparable lack of equilibrium behavior is also noted in the electronic degrees of freedom but with populations corresponding to spin–orbit temperatures (TSO) consistently higher than Trot by ∼15 K. These results unambiguously demonstrate evaporation into a non-equilibrium distribution, which, by detailed-balance considerations, predict quantum-state-dependent sticking coefficients for incident collisions of NO at the gas–liquid interface. Comparison and parallels with previous experimental studies of NO thermal desorption and molecular-beam scattering in other systems are discussed, which suggests the emergence of a self-consistent picture for the non-equilibrium dynamics.
High p-conductivity in AlGaN enabled by polarization field engineering
Authors: Rathkanthiwar Shashwat , Reddy Pramod , Moody Baxter , Quiñones-García Cristyan , Bagheri Pegah , Khachariya Dolar , Dalmau Rafael , Mita Seiji , Kirste Ronny , Collazo Ramón , Sitar Zlatko
Published: April 2023

High p-conductivity (0.7 Ω−1 cm−1) was achieved in high-Al content AlGaN via Mg doping and compositional grading. A clear transition between the valence band and impurity band conduction mechanisms was observed. The transition temperature depended strongly on the compositional gradient and to some degree on the Mg doping level. A model is proposed to explain the role of the polarization field in enhancing the conductivity in Mg-doped graded AlGaN films and the transition between the two conduction types. This study offers a viable path to technologically useful p-conductivity in AlGaN.
Perspective: Antichiral magnetic topological photonics
Authors: Ji Zitao , Chen Jianfeng , Li Zhi-Yuan
Published: April 2023

Topological photonics has recently opened up a promising frontier for electromagnetic wave and light manipulation and has made great progress from unique physical concepts to novel practical photonic devices. Numerous works have discussed the realizations of chiral topological photonic states in magnetic photonic crystals with broken time-reversal symmetry; however, limited reports have been discussed to the achievements of antichiral topological photonic states. In this Perspective, we review recent progress in antichiral topological photonic states in magnetic photonic systems for the basic concepts, properties, and applications. Additionally, we provide an outlook for emerging frontier topics, promising opportunities, fundamental challenges, and potential applications for antichiral magnetic topological photonics.
Gate-controlled photoresponse improvement in b-AsP/WSe2 heterostructures with type-I band alignment
Authors: Zhao Feiping , Wang Danyang , Zhang Fen , Cui Baocheng , Xia Qinglin , Zhong Mianzeng
Published: April 2023

As a promising two-dimensional (2D) layered material, black arsenic phosphorus (b-AsP) alloys have received growing attention due to their unique properties and their ability for high-performance broadband photodetection. However, high dark current and slow response speed have already become bottlenecks for further development. Manual vertical van der Waals heterojunctions made of different 2D materials offer opportunities to alleviate such bottlenecks in a simple and low-energy way. The rational design of band alignment can facilitate device performance. In this work, we design and achieve a type-I vertically stacked WSe2/b-As0.084P0.916 device, which exhibits a rectification ratio of 102 along with an unusual backward current as low as 10−12 A. As such, this device can function as an ultrasensitive photodetector, which shows excellent photoresponse properties from the visible to near-infrared region (275–850 nm), with a responsivity of 244 A/W, a specific detectivity of 2.27 × 1012 Jones, and a fast response speed of τrise ≈ 5.1 ms and τdecay ≈ 4 ms. Compared to the dark state, the hole mobility under light stimulation is raised more than ten times (from 1.1 to 12.1 cm2 V−1 s−1), which contributes to numerous excited electron–hole pair transfers from WSe2 to b-As0.084P0.916. The responsivity and detectivity increase by 5 and 3 orders of magnitude, respectively, after applying gate voltage, indicating remarkable gate-controlled properties. These results suggest that the WSe2/b-As0.084P0.916 heterostructure is a promising candidate for future electronic and optoelectronic applications.
Quantum version of the integral equation theory-based dielectric scheme for strongly coupled electron liquids
Authors: Tolias Panagiotis , Lucco Castello Federico , Dornheim Tobias
Published: April 2023

A novel dielectric scheme is proposed for strongly coupled electron liquids, which handles quantum mechanical effects beyond the random phase approximation level and treats electronic correlations within the integral equation theory of classical liquids. The self-consistent scheme features a complicated dynamic local field correction functional and its formulation is guided by ab initio path integral Monte Carlo simulations. Remarkably, our scheme is capable of providing unprecedently accurate results for the static structure factor with the exception of the Wigner crystallization vicinity, despite the absence of adjustable or empirical parameters.
Assessment of bonding characteristic of β-(AlxGa1−x)2O3 alloys from photoluminescence and x-ray absorption near edge spectroscopy
Authors: Bhattacharjee Jayanta , Gupta R. K. , Singh S. D.
Published: April 2023

Bonding characteristics of the β-(AlxGa1−x)2O3 alloy have been assessed from red luminescence and x-ray absorption near edge spectroscopy (XANES). Red luminescence, known as R1 and R2 lines, originates from crystal field split d-levels of unintentionally present Cr3+ ions in the β-(AlxGa1−x)2O3 alloy, is found to blueshift with Al composition. This indicates that the nephelauxetic effect in β-Ga2O3 materials decreases with Al substitution, which results to a decrease in the covalency of the β-(AlxGa1−x)2O3 alloy. The XANES experiments at the oxygen K-absorption edge provide clear evidence of the decrease in the covalency of the alloy, where an absorption peak representing the covalency in the β-Ga2O3 material is found to decrease with an increase in the Al composition. Furthermore, the nature of the observed red luminescence for the β-(AlxGa1−x)2O3 alloy is determined to be excitonic recombination. Our results further confirm the fact that the red luminescence from Cr3+ ions is an excellent local probe to assess the bonding characteristic of the host material.
Collective transport and reconfigurable assembly of nematic colloids by light-driven cooperative molecular reorientations
Authors: Jiang Jinghua , Wang Xinyu , Akomolafe Oluwafemi Isaac , Tang Wentao , Asilehan Zhawure , Ranabhat Kamal , Zhang Rui , Peng Chenhui
Published: April 2023

Nanomotors in nature have inspired scientists to design synthetic molecular motors to drive the motion of microscale objects by cooperative action. Light-driven molecular motors have been synthesized, but using their cooperative reorganization to control the collective transport of colloids and to realize the reconfiguration of colloidal assembly remains a challenge. In this work, topological vortices are imprinted in the monolayers of azobenzene molecules which further interface with nematic liquid crystals (LCs). The light-driven cooperative reorientations of the azobenzene molecules induce the collective motion of LC molecules and thus the spatiotemporal evolutions of the nematic disclination networks which are defined by the controlled patterns of vortices. Continuum simulations provide physical insight into the morphology change of the disclination networks. When microcolloids are dispersed in the LC medium, the colloidal assembly is not only transported and reconfigured by the collective change of the disclination lines but also controlled by the elastic energy landscape defined by the predesigned orientational patterns. The collective transport and reconfiguration of colloidal assemblies can also be programmed by manipulating the irradiated polarization. This work opens opportunities to design programmable colloidal machines and smart composite materials.
Cross-language influences in bilingual processing and second language acquisition
Authors: Elgort Irina , Siyanova-Chanturia Anna , Brysbaert Marc
Published: April 2023

In this chapter, we situate cross-language influences as an interdisciplinary research topic, outline the structure of the volume, and highlight key points from the state-of-the-art review chapters. The chapters critically evaluate the present state of research into cross-language influences across three core domains of linguistic knowledge (phonology, lexicon, and morphosyntax) and identify promising directions for future interdisciplinary research.
Cross-language influences in the acquisition of L2 and L3 phonology
Authors: Amengual Mark
Published: April 2023

This chapter synthesises some of the main findings from research investigating cross-language influence (CLI) in Second Language (L2) and Third Language (L3) speech learning. In addition to an overview of the findings that have gathered growing consensus in the fields of L2 and L3 phonology, and how these results have been tested and explained in various theories of L2 speech, this chapter points to methodological and theoretical considerations discussed in three areas that hold promise for future research in L2 and L3 speech: (i) the relationship between L2/L3 speech perception and L2/L3 speech production, (ii) the acquisition of phonological processes vs. phonological contrasts, and (iii) the distinction between static and dynamic phonetic interactions in L2 and L3 speech.
Cross-language influences in L2 visual word processing
Authors: van Heuven Walter J.B. , Dijkstra Ton
Published: April 2023

Over the last decades, a variety of verbal models have been proposed to account for empirical findings on bilingual word processing and second language (L2) acquisition. However, in these domains only a small number of computational models have seen the light, including localist connectionist models like the Bilingual Interactive Activation (BIA) model (Dijkstra & van Heuven, 1998; van Heuven et al., 1998), the Bilingual Interactive Activation + (BIA+) model (Dijkstra & van Heuven, 2002), and Multilink(+) (Dijkstra et al., 2019; 2022a). In this chapter, we review structural and processing characteristics of these models, such as input coding, lateral inhibition, word frequency, language nodes, and task demands. Finally, advantages and limitations of current computational models are discussed.
Cross-language influences in the acquisition of L2 multiword expressions
Authors: Wolter Brent
Published: April 2023

As with all aspects of L2 acquisition, the L1 has a marked influence on the acquisition of multiword expressions (MWEs). However, providing a unified framework to explain the L1’s influence on the acquisition of MWEs is challenging, particularly because MWEs vary in a number of ways. In this chapter, I begin by discussing various types of MWEs and how these can affect acquisition. I then move on to review research to date documenting the L1’s influence on L2 MWE acquisition before considering additional factors that have been shown to alter the effects of the L1. I conclude by calling for a holistic account of the acquisition of L2 MWEs that incorporates the influence of the L1 and other additional factors.
Prosodic interaction in Cantonese-English bilingual children’s speech production
Authors: Lee Jonathan Him Nok , Lai Regine Yee King , Matthews Stephen , Yip Virginia
Published: April 2023

This corpus-based study investigates intonation patterns in the production of Cantonese by Cantonese-English
bilingual children. We examine the intonation patterns in eight simultaneous bilingual children acquiring a tonal (Cantonese) and
an intonational language (English) from 2;0 to 3;0. Two intonation patterns are observed in all the bilingual children studied:
high pitch followed by a fall (including H_H*L% and H_L*L%) and low pitch followed by a rise (including L_H*H% and L_L*H%), in
which English-like intonation is applied to Cantonese and code-mixed utterances. They illustrate cross-linguistic influence in
prosody from English in the bilingual children’s early phonological development. Language dominance, use of sentence-final
particles, and the children’s grammatical complexity are found to be significant predictors for the production of bilingual
intonation. First, the more dominant the child is in Cantonese, the less bilingual intonation is produced in Cantonese and
code-mixed utterances. Second, bilingual intonation is significantly more likely to be produced in utterances with sentence-final
particles than without. Third, the greater the child’s grammatical complexity, the lower the predicted probability of producing
bilingual intonation.
Crosslinguistic paths of pragmatic development
Authors: Beeching Kate , Crible Ludivine
Published: April 2023

Diachronic studies of discourse markers suggest they follow a unidirectional developmental path, from
propositional to textual and expressive uses. The present study tests whether children acquire the propositional (literal) before
the expressive (pragmatic) functions of two adversative discourse markers in French and English, which have similar core meanings
and pragmatic functions. Our results partially confirm the propositional-first hypothesis but semantics and pragmatics appear to
work together, rather than first one then the other, at least in this case, and this runs counter to both diachronic theories and
usage-based accounts of L1 acquisition. 88 occurrences of en fait and 174 of actually were
extracted from the CHILDES database, and coded for two functions (adversative and elaborative) and three domains (propositional,
textual, expressive). The results suggest that the pragmatic functions of actually are used by children as young
as two years old, but the same is not true of en fait, which is almost exclusively propositional in the early
years. By contrast, before age 5, French children start to use en fait for textual and elaborative functions to a
greater extent than actually. The role of syntactic position and parental input are discussed.
Dynamics of charged particles around weakly magnetized loop quantum gravity black hole
Authors: Majeed Bushra , Rahim Rehana , Rayimbaev Javlon
Published: April 2023

In this article, we have studied the dynamics of electrically and magnetically charged particles in the spacetime of loop quantum gravity-corrected Schwarzschild black hole (LQGBH). We consider the loop quantum gravity (LQG) immersed in an external asymptotically uniform magnetic field. The effects of LQG spacetime on dynamics of the particles is studied. We have discussed the circular orbits of the particles about the central object and studied the dependence of the inner stable circular orbits (ISCOs) on the magnetic coupling parameter and the black hole parameters. The synchrotron radiations coming out of the charged particle (accelerated by electromagnetic forces Coulomb and Lorentz) in the surrounding of the magnetized LQGBH is analysed. We have also studied the effects of LQG parameters on the specific angular momentum, energy and ISCOs. We calculated the minimum energy and angular momentum of the magnetized particles required to move in the ISCO. We did this analysis by first calculating the magnetic coupling parameter of the LQGBH spacetime. We have also investigated the collision of neutral, electrically and magnetically charged particles and their centre of mass energy. It is observed that magnetic field around black hole increases the particle acceleration around LQGBH.
A laboratory-scale greenhouse for spectroscopic monitoring of plants and associated gas-phase isotopic fractionation
Authors: Greer Samuel M , Robel Istvan , Beveridge Andrew C , Anderson Aaron S , Martinez Ronald K , Currier Robert P , Perkins George B , Thalmann Leslie , Nowak-Lovato Kristy L
Published: April 2023

The ability to monitor isotopic fractionation in terrestrial ecosystems is a challenge due to the presence of interacting variables. A laboratory-scale apparatus for controlled experiments could serve as a useful platform to deconvolute the variables that affect isotopic fractionation. Such a device could offer a powerful means to understand fractionation of carbon stocks in terrestrial ecosystems and to probe the effects of photosynthesis or interactions between the soil and plants on carbon fractionation. To this end, an enclosed and artificially-lit benchtop soil and plant chamber was constructed and equipped to monitor atmospheric isotopic composition. Fourier-transform infrared (FTIR) spectroscopy was employed for isotopic sensing since it enables in-situ measurements. The validity of FTIR for isotopic ratio determination was confirmed by comparing FTIR and isotope ratio mass spectrometry data for a series of CO2 gas samples with known quantities of 13C and 12C. The greenhouse chamber was also equipped with an optically-based trace gas analyzer capable of continuously tracking CO2, CH4, and H2O concentrations and a residual gas analyzer mass spectrometer. Reflectance spectroscopy was also incorporated by way of sealed fiber optic feed-throughs coupled to a spectro-radiometer, for quantifying changes in leaf spectra induced by various environmental stressors. The resulting greenhouse chamber can be a useful tool for determining the effects of atmospheric trace gases on plant morphology and physiology as a function of concentration and isotopic composition. Microecosystems can be examined under controlled laboratory conditions and a wide variety of plant species can be accommodated. The bench-scale greenhouse should prove useful in assessing the impact of environmental variables and in guiding the design of field experiments.
Multi-image hybrid super-resolution reconstruction via interpolation and multi-scale residual networks
Authors: Wu Qiang , Zeng Hongfei , Zhang Jin , Xia Haojie
Published: April 2023

High spatial resolution is necessary for several applications such as visual inspection, and can be achieved using high-resolution (HR) image sensors or through image super-resolution (SR) algorithms. Currently, SR algorithms are applied to either single low-resolution (LR) images or multiple LR image sequences. In this paper, we propose a hybrid super-resolution (HYSR) framework to generate HR images by combining multi-image super-resolution (MISR) and single-image super-resolution (SISR) to obtain high spatial resolution images. This method comprehensively utilizes sub-pixel-level high-frequency detail information between multiple images and co-occurrence prior of a single image to reconstruct SR images with a larger scale factor than the existing methods. Generally, the HYSR reconstruction results have more satisfactory details and visual quality than the SISR or MISR reconstruction results. A large number of qualitative and quantitative evaluation results demonstrate the effectiveness and superiority of the HYSR method over traditional MISR and SISR methods.
Degradation trend feature generation improved rotating machines RUL prognosis method with limited run-to-failure data
Authors: Zhang Kai , Liu Yantao , Zou Yisheng , Ding Kun , Liu Yongzhi , Zheng Qing , Ding Guofu
Published: April 2023

The success of rotating machines’ data-driven remaining useful life (RUL) prognosis approaches depends heavily on the abundance of entire life cycle data. However, it is not easy to obtain sufficient run-to-failure data in industrial practice. Data generation technology is a promising solution for enriching data but fails to address the intrinsic complexity of nonlinear stage degradation and the time correlation of long-term data. This research proposes an RUL prognosis approach improved by the degradation trend feature generation variational autoencoder. First, this study develops a framework combining degradation trend generation features to resolve the issue of capturing the elements of time distribution for run-to-failure data. Second, a generation variational autoencoder network with a tendency block is proposed to create high-quality time series data correlation features. Third, original and created degradation trend features are subjected to deep adaptive fusion and health indicator extraction. A bi-directional long short-term memory network is employed to predict the degradation trend and obtain the RUL prognosis. Finally, the proposed approach’s feasibility is confirmed by cross-validation experiments on a bearing dataset, which reduces the prediction error by 22.309%.
Impact attenuation capabilities of new and used football helmets
Authors: Breedlove Evan L , Breedlove Katherine Morigaki , Bowman Thomas G , Lininger Monica R , Nauman Eric A
Published: April 2023

Football helmets are expected to break down with use, and reconditioning recommendations are required to be stated by manufacturers. However, the degree of change in helmet impact mitigation performance as a function of usage is not generally known. Therefore, this study aimed to compare the ability of football helmets to attenuate impacts after a single season of regular collegiate use to unused helmets. Three never-used Riddell® Speed™ helmets were tested and compared to three used helmets which had been used during one season of Division 1 collegiate football. Helmets were tested at three velocities (3.46, 4.88, and 5.46 m s−1) on six locations in ambient temperature, simulating National Operating Committee on Standards for Athletic Equipment certification drop tests. The interaction between helmet age and location during all three velocities (P

⩽

0.0001), indicating that there were differences in Gadd severity index (GSI) between new and used helmets after accounting for location-specific differences. Similar analysis for peak linear acceleration (PLA) found significant interactions for all three velocities (P

⩽

0.003). Additional analyses found differences in velocity-dependence for several impact locations. In most cases, used helmets yielded lower GSI and PLA relative to new helmets. The reduction in impact metrics for used helmets indicates initial break-in with impact mitigation benefits, but the long-term consequences of continued use are unclear. The implications of these differences on injury risk and susceptibility remain unknown; however, the results suggest that further studies could inform helmet reconditioning guidelines and development of new smart materials designed to monitor and/or prevent breakdown in padding.
Full waveform inversion as training a neural network
Authors: Zhang Wensheng , Chen Zheng
Published: April 2023

Full waveform inversion (FWI) is usually solved as a nonlinear least-squares problem to minimize the discrepancy between the recorded signal and the synthetic data by some gradient-based optimization methods. In this paper, we investigate acoustic FWI as training a neural network. We recast the time-domain difference scheme into a forward propagation process of vanilla recurrent neural network (RNN) and then find that the parameters of RNN coincide with the physical parameters in the wave equation. As a result, the FWI problem is resolved as training such a kind of neural network. Some stochastic optimization methods such as the Adam optimizer are applied to update the model parameters. We demonstrate our method numerically with three typical models including the benchmark Marmousi model. The numerical results show that the fast convergence and good velocity inversion result can be achieved.
Hole transport through an isotype amorphous-crystalline Ge2Sb2Te5 heterojunction under forward bias
Authors: Nagendra Arun , Trombley Jeremy B , Chan Erwin H W
Published: April 2023

The transport of holes through a representative isotype amorphous-crystalline Ge2Sb2Te5 heterojunction under forward bias is explored for the first time. An approximate analytic model, based on the exact solution to Poisson’s equation, the Continuity equation, and the Transport equation, is proposed to describe the forward current-voltage characteristic and hole quasi-Fermi level distribution across the heterojunction with a reduced set of material and device parameters. The proposed model incorporates thermionic emission across the heterojunction interface as well as drift and diffusion across the quasi-neutral regions of the heterojunction layers, but neglects drift and diffusion across the space-charge regions of the heterojunction layers, as well as recombination. Solar cell capacitance simulation results demonstrate general agreement between the approximate and exact solutions. Therefore, the approximate model is effective in capturing the physics of thermionic emission-limited transport at low applied bias and drift-diffusion-limited transport through the quasi-neutral region of the amorphous layer at larger applied biases. However, simulation results also show that an extremely narrow subregion of the space-charge region within the amorphous layer, which has been neglected within the proposed model, limits the transport of holes at very low bias and inhibits transport at all other biases. Nevertheless, the proposed model provides improved accuracy across the entire bias range compared to the individual thermionic emission or drift-diffusion models.
A Transparent broadband all-dielectric water-based metamaterial absorber based on laser cutting
Authors: Li Lintao , Wen Jingda , Wang Yichen , Jin Yue , Wen Yongzheng , Sun Jingbo , Zhao Qian , Li Bo , Zhou Ji
Published: April 2023

Gradually attracting attention on the all-dielectric broadband metamaterial absorber is developing in the application of multi-functionalization, such as the optical transparent transmission function of the microwave absorber. In this paper, we designed an all-dielectric transparent broadband metamaterial absorber utilizing the composited structure of the layered and cylindrical water with the shell of cross-shaped PMMA. Then, the series of the patterned shell are fabricated by the two-dimensional laser cutting technology with ultra-fast, accurate, and simplified process. Both the simulated and experimental performance show high absorption over 90% at 13.3–40 GHz and optical transmittance of 73% with polarization insensitivity and wide-angle incident tolerance. Furthermore, the transparent absorber can modulate the low-frequency absorptivity by adjusting the temperature and ion concentration. Our all-dielectric transparent broadband metamaterial absorber based on laser cutting technology has promising potential in a wider range of both civil and military applications.
A tale of two (or more) h's
Authors: Brieden Samuel , Gil-Marín Héctor , Verde Licia
Published: April 2023

We use the large-scale structure galaxy data (LSS) from the BOSS and eBOSS surveys, in
combination with abundances information from Big Bang Nucleosynthesis (BBN), to measure two values
of the Hubble expansion rate, H
0 = 100h [ km s-1 Mpc-1], each of them
based on very different physical processes. One is a (traditional) late-time-background
measurement, based on determining the BAO scale and using BBN abundances on baryons for
calibrating its absolute size (BAO+BBN). This method anchors H
0 to the (standard) physics of
the sound horizon scale at pre-recombination times. The other is a newer, early-time based
measurement, associated with the broadband shape of the power spectrum. This second method anchors
 H
0 to the physics of the matter-radiation equality scale, which also needs BBN information for
determining the suppression of baryons in the power spectrum shape (shape+BBN). Within the
ΛCDM model, we find very good consistency among these two H
0's: BAO+BBN (+growth)
delivers H
0 = 67.42+0.88
-0.94 (67.37+0.86
-0.95) km s-1Mpc-1, whereas the
shape+BBN (+growth) delivers H
0 = 70.1+2.1
-2.1 (70.1+1.9
-2.1) km s-1 
Mpc-1, where `growth' stands for information from the late-time-perturbations captured by the
growth of structure parameter. These are the tightest sound-horizon free H
0 constraints from
LSS data to date.

As a consequence, to be viable any ΛCDM extension proposed to address the so-called “Hubble
tension” needs to modify consistently not only the sound horizon scale physics, but also the
matter-radiation equality scale, in such a way that both late- and early-based H
0's return
results mutually consistent and consistent with the high H
0 value recovered by the standard
cosmic distance ladder (distance-redshift relation) determinations.
Enhanced prospects for direct detection of inelastic dark matter from a non-galactic diffuse component
Authors: Herrera Gonzalo , Ibarra Alejandro , Shirai Satoshi
Published: April 2023

In some scenarios, the dark matter particle predominantly scatters inelastically with the target, producing a heavier neutral particle in the final state. In this class of scenarios, the reach in parameter space of direct detection experiments is limited by the velocity of the dark matter particle, usually taken as the escape velocity from the Milky Way. On the other hand, it has been argued that a fraction of the dark matter particles in the Solar System could be bound to the envelope of the Local Group or to the Virgo Supercluster, and not to our Galaxy, and therefore could carry velocities larger than the escape velocity from the Milky Way. In this paper we estimate the enhancement in sensitivity of current direct detection experiments to inelastic dark matter scatterings with nucleons or electrons due to the non-galactic diffuse components, and we discuss the implications for some well motivated models.
Unified theory of quantum crystals and optical lattices with Bose–Einstein condensate
Authors: Yukalov V I
Published: April 2023

When interactions between particles are strong, at low temperature, these particles can form self-organized quantum crystals, and when the particles interact weakly, periodic structures can be imposed by external fields, e.g. by optical lattices. These opposite cases usually are treated separately, dealing either with quantum crystals or with optical lattices. Here the unified theory is developed for arbitrary particle interaction strength, treating in the frame of the same model both the limiting cases of quantum crystals and optical lattices, as well as the states intermediate between these two limits. Bose particles are considered, hence at low temperature in optical lattices Bose–Einstein condensation can happen, while it seems to be prohibited in ideal quantum crystals that do not contain mesoscopic regions of disorder, such as dislocations and grain boundaries.
L-shell x-ray fluorescence relative intensities for elements with 62 ≤ Z ≤ 83 at 18 keV and 23 keV by synchrotron radiation
Authors: Alqadi M , Al-Humaidi S , Alkhateeb H , Alzoubi F
Published: April 2023

The relative intensities of L-subshell x-ray fluorescence (XRF) for elements with atomic numbers 62 ≤ Z ≤ 83 were measured at two excitation energies, 18 keV and 23 keV, using a synchrotron radiation source at a beamline of the Synchrotron Light Center for Experimental Science and Applications in the Middle East (SESAME), Jordan. The experimentally measured results of the relative intensities were compared with the calculated results using the subshell fluorescence yield and the Coster–Kronig transition probabilities recommended by Campbell and the values based on the Dirac–Hartree–Slater model by Puri. The experimental and theoretical results are in agreement. In this work, L XRF relative intensities for the elements Sm, Gd, Tb, Er, Ta, W, Re, Hg, Pb and Bi at energies of 18 keV and 23 keV were measured.
FPGA based hardware platform for trapped-ion-based multi-level quantum systems
Authors: Zhu 朱 Ming-Dong 明东 , Yan 闫 Lin 林 , Qin 秦 Xi 熙 , Zhang 张 Wen-Zhe 闻哲 , Lin 林 Yiheng 毅恒 , Du 杜 Jiangfeng 江峰
Published: April 2023

We report a design and implementation of a field-programmable-gate-arrays (FPGA) based hardware platform, which is used to realize control and signal readout of trapped-ion-based multi-level quantum systems. This platform integrates a four-channel 2.8 Gsps@14 bits arbitrary waveform generator, a 16-channel 1 Gsps@14 bits direct-digital-synthesis-based radio-frequency generator, a 16-channel 8 ns resolution pulse generator, a 10-channel 16 bits digital-to-analog-converter module, and a 2-channel proportion integration differentiation controller. The hardware platform can be applied in the trapped-ion-based multi-level quantum systems, enabling quantum control of multi-level quantum system and high-dimensional quantum simulation. The platform is scalable and more channels for control and signal readout can be implemented by utilizing more parallel duplications of the hardware. The hardware platform also has a bright future to be applied in scaled trapped-ion-based quantum systems.
Optimization of large-area YBa2Cu3O7–δ
thin films by pulsed laser deposition for planar microwave devices
Authors: Xiong Pei-Yu , Chen Fu-Cong , Feng Zhong-Pei , Yang Jing-Ting , Xia Yu-Dong , Yuan Yue-Feng , Wang Xu , Yuan Jie , Wu Yun , Shi Jing , Jin Kui
Published: April 2023

This paper presents high quality YBa2Cu3O7–δ
(YBCO) thin films on LaAlO3 substrate for microwave devices prepared by pulsed laser deposition (PLD). The double-sided YBCO films cover a large area and have been optimized for key parameters relevant to microwave device applications, such as surface morphology and surface resistance (R
s). This was achieved by improving the target quality and increasing the oxygen pressure during deposition, respectively. To evaluate the suitability of the YBCO films for microwave devices, a pair of microwave filters based on microstrip fabricated on films from this work and a commercial company were compared. The results show that the YBCO films in this work could completely meet the requirements for microwave devices.
Absolute frequency measurement of a Yb optical clock at the limit of the Cs fountain
Authors: Goti Irene , Condio Stefano , Clivati Cecilia , Risaro Matias , Gozzelino Michele , Costanzo Giovanni A , Levi Filippo , Calonico Davide , Pizzocaro Marco
Published: April 2023

We present the new absolute frequency measurement of ytterbium (171Yb) obtained at INRiM with the optical lattice clock IT-Yb1 against the cryogenic caesium (133Cs) fountain IT-CsF2, evaluated through a measurement campaign that lasted 14 months. Measurements are performed by either using a hydrogen maser as a transfer oscillator or by synthesizing a low-noise microwave for Cs interrogation using an optical frequency comb. The frequency of the 171Yb unperturbed clock transition

1

S

0

→

3

P0 results to be 518 295 836 590 863.44(14) Hz, with a total fractional uncertainty of

2.7
×

10

−
16

that is limited by the uncertainty of IT-CsF2. Our measurement is in agreement with the Yb frequency recommended by the Consultative Committee for Time and Frequency. This result confirms the reliability of Yb as a secondary representation of the second and is relevant to the process of redefining the second in the International System of Units on an optical transition.
MHD modeling of shattered pellet injection in JET
Authors: McClenaghan J. , Lyons B.C. , Kim C.C. , Akçay C. , Eidietis N. , Lao L.L. , Sweeney R.M. , Stein-Lubrano B. , Sheikh U. , Hawkes N. , Szepesi G.
Published: April 2023

Nonlinear 3D MHD simulations of shattered-pellet injection (SPI) in JET show prototypical SPI-driven disruptions using the M3D-C1 and NIMROD extended-MHD codes. Initially, radiation-driven thermal quenches are accelerated by MHD activity as the pellet crosses rational surfaces, leading to a radiation spike, global stochasticization of the magnetic field, and a complete thermal quench. Eventually, current quenches, preceded by a current spike are seen as the Ohmic heating becomes equal to the radiative cooling. The results are qualitatively similar for both a single monolithic pellet, pencil-beam model, and a realistic shatter to represent the SPI plume. A scan in viscosity from 500 to 2000 m2 s−1 for MHD simulations finds that reducing viscosity increases MHD activity and decreases thermal quench time slightly. A realistic cloud of fragments modeling shows that mixed-D–Ne pellet travels deeper into the plasma core before the thermal quench. At the slow pellet speeds, the pellet is found to be moving slowly enough inward that even the 5% neon in the mixed pellet is enough to effectively radiate the thermal energy available. Radiation toroidal peaking is predicted to be at levels consistent with experimental observations and reduced as the pellet travels deeper into the plasma. These simulations lay the ground work for more-sophisticated validative and predictive modeling of SPI in JET using both M3D-C1 and NIMROD.
Wavelength-shifter coated polystyrene as an easy-to-build and low-cost plastic scintillator detector
Authors: Brignoli A. , Conaboy A. , Dormenev V. , Jimeno D. , Kazlou D. , Lacker H. , Scharf C. , Schmidt J. , Zaunick H.G.
Published: April 2023

We studied the light yield of a pure polystyrene slide
coated with wavelength-shifter molecules, coupled to a
photomultiplier, using β
- particles from a 90Sr
source, as a possible easy-to-build, low-cost plastic scintillator
detector. Comparison measurements were performed with an uncoated
polystyrene slide as well as with uncoated and coated PMMA slides,
the latter which can only produce Cherenkov light when being
traversed by charged particles. The results with the single (double)
coated polystyrene slides show about 4.9 (6.3) times higher detected
photon yield compared to the uncoated slide. For comparison, the
light yield of a polystyrene-based extruded plastic scintillator
material doped with PTP and POPOP was measured as well. The
absolute detected light yield motivates future studies for
developing easy-to-build, low-cost polystyrene-based plastic
scintillator detectors.
Optimization of the injection beam line at the Cooler Synchrotron COSY using Bayesian Optimization
Authors: Awal A. , Hetzel J. , Gebel R. , Kamerdzhiev V. , Pretz J.
Published: April 2023

The complex non-linear processes in multi-dimensional
parameter spaces, that are typical for an accelerator, are a natural
application for machine learning algorithms. This paper reports on
the use of Bayesian optimization for the optimization of the
Injection Beam Line (IBL) of the Cooler Synchrotron storage ring
COSY at the Forschungszentrum Jülich, Germany. Bayesian
optimization is a machine learning method that optimizes a
continuous objective function using limited observations. The IBL is
composed of 15 quadrupoles and 28 steerers. The goal is to increase
the beam intensity inside the storage ring. The results showed the
effectiveness of the Bayesian optimization in achieving
better/faster results compared to manual optimization.
Measurement of the Compton scattering in germanium with a p-type point-contact germanium detector for dark matter detection
Authors: Hu J.W. , Yang L.T. , Yue Q. , Geng X.P. , Li H.B. , Liang Y.F. , Lin S.T. , Liu S.K. , Ma H. , Wang L. , Wong H.T. , Zhang B.T.
Published: April 2023

Low-energy background through Compton scattering from the
ambient γ rays can be contaminated in direct dark matter
search experiments. In this paper, we report comparable measurements
on low-energy spectra via Compton scattering from several
γ-ray sources with a p-type point-contact germanium
detector. The spectra between 500 eV and 18 keV have been measured
and analyzed. Moreover, the features of the electron binding effect,
particularly at the edges of the K- and L-shells in the germanium
atom, were observed with different gamma sources and were consistent
with the models in the Geant4 simulation. An empirical background
model is proposed that provides insights into understanding the
low-energy background in germanium for direct dark matter
experiments.
Evaluation of a method for time-of-flight, wavelength and neutron flight path calibration for neutron scattering instruments by means of a mini-chopper and standard neutron monitors
Authors: Vergara L. , Arai M. , Woracek R. , Olsson M. , Quintanilla A. , Alcock S. , Nilsson J. , Kanaki K. , Kadletz P.M. , Kirstein O. , Hall-Wilton R. , Tsapatsaris N.
Published: April 2023

Accurate conversion of neutron time-of-flight (TOF) to wavelength is of fundamental importance to neutron scattering measurements in order to ensure the accuracy of the instruments and the experimental results. Equally important in these measurements is the determination of uncertainties, and with the appropriate precision. Especially in cases where instruments are highly configurable, the determination of the absolute wavelength after any change must always be performed (e.g. change of detector position). Inspired by the manner with which neutron spectrometers determine the absolute wavelength, we evaluate for the first time, in the author's knowledge, a commonly used method for converting TOF to neutron wavelength by measuring the neutron flight path length from the source of neutrons to a monitor and we proceed to analytically calculate the uncertainty contributions that limit the precision of the conversion. The method was evaluated at the V20 test beamline at the Helmholtz Zentrum Berlin (HZB), emulating the ESS source with a long pulse of 2.86 ms length and 14 Hz repetition rate, by using a mini-chopper operated at 140 Hz and two portable beam monitors (BMs), as well as accompanied data acquisition infrastructure. The mini-chopper created well-defined neutron pulses and the BM was placed at two positions, enabling the average wavelength of each of the pulses created to be determined. The used experimental setup resulted in absolute wavelength determination at the monitor positions with a δλ
mean / λ
mean of ∼1.8% for λ > 4 Å. With the use of a thinner monitor, a δλ
mean / λ
mean of ∼1% can be reached and with a modest increase of the distance between the reference monitor positions a δλ
mean / λ
mean of below 0.5% can be achieved. Further improvements are possible by using smaller chopper disc openings and a higher rotational speed chopper. The method requires only two neutron measurements and doesn't necessitate the use of crystals or complex fitting with sigmoid functions and multiple free variables, and could constitute a suitable addition to imaging, diffraction, reflectometers and small angle neutron scattering instruments, at spallation sources, that do not normally utilise fast choppers.