bluuebunny/crossref_metadata_2025_split huggingface dataset:
Observable characteristics of the charged black hole surrounded by thin disk accretion in Rastall gravity
Authors: Guo Sen , Li Guan-Ru , Liang En-Wei 
Published: May 2022

Abstract
The observable characteristics of the charged black hole (BH) surrounded by a thin disk accretion are investigated in the Rastall gravity. We found that the radii of the direct emission, lensing ring, and photon ring dramatically increased as the radiation field parameter increased, but they only weakly depend on the BH charge. Three positions of the radiation accretion disk relative to the BH are considered, i.e. the innermost accretion disk is closed to the radii of the innermost stable circular orbit, the photon ring of the BH, and the event horizon of the BH. The observed images in three cases respectively are obtained. It is found that the total observed flux is dominated by the direct emission, the lensing ring provides a small contribution, and the photon ring is negligible. The lensing and photon rings could not be observed in the blurred image with the EHT resolution. Our results suggest that the observable characteristics of the charged BH surrounded by the thin disk accretion in the Rastall gravity depend on both the BH space-time structure and the position of the radiating accretion disk with respect to the BH. The research of these BH images may serve as a probe for the BH-disk structure in M87* like nearby active galactic nuclei.
Broadband and high-efficient reflective linear-to-circular polarizer with Wi-Fi shaped metasurface
Authors: Tian Feng , Wang Yuxiang , He Jiahao , Hao Han , Ma Xia , Huang Xiaojun 
Published: May 2022

Abstract
Arbitrarily manipulating the polarization states of electromagnetic waves has gained interest due to its wide application in modern wireless communication systems. However, conventional polarizers face major bottlenecks such as bulky size, low efficiency and narrow frequency band. This paper proposes a reflective linear-to-circular polarizer using Wi-Fi shaped metasurface, and the designed polarizer can efficiently convert the linearly polarized incident waves into nearly perfect circularly polarized reflected waves in wideband frequency region of 12.1–20 GHz. Based on simulations, the polarizer has an axial ratio of ⩽3 dB at 12.1–20 GHz and a relative bandwidth of 49.2%. The polarization conversion rate is over 97% in 12.1–20 GHz. The physical analysis of the polarization conversion is based on the surface current distributions. To validate the simulations, microwave tests are carried out, and the theory, simulations, and experiments all accord quite well.
Strain assisted magnetoelectric coupling in ordered nanomagnets of CoFe2O4/SrRuO3/(Pb(Mg1/3Nb2/3)O3–PbTiO3) heterostructures
Authors: Ahlawat Anju , Khan Azam Ali , Deshmukh Pratik , Bhartiya Sushmita , Satapathy S , Shirolkar Mandar M , Wang Haiqian , Choudhary R J 
Published: May 2022

Abstract
We have explored the electric field controlled magnetization in the nanodot CoFe2O4/SrRuO3/PMN-PT (CFO/SRO/PMN-PT) heterostructures. Ordered ferromagnetic CFO nanodots (∼300 nm lateral dimension) are developed on the PMN-PT substrate (ferroelectric as well as piezoelectric) using a nanostencil-mask pattering method during pulsed laser deposition. The nanostructures reveal electric field induced magnetization reversal in the single domain CFO nanodots through transfer of piezostrains from the piezoelectric PMN-PT substrate to the CFO. Further, electric field modulated spin structure of CFO nanomagnets is analyzed by using x-ray magnetic circular dichroism (XMCD). The XMCD analysis reveals cations (Fe3+/Co2+) redistribution on the octahedral and tetrahedral site in the electric field poled CFO nanodots, establishing the strain induced magneto-electric coupling effects. The CFO/SRO/PMN-PT nanodots structure demonstrate multilevel switching of ME coupling coefficient (α) by applying selective positive and negative electric fields in a non-volatile manner. The retention of two stable states of α is illustrated for ∼106 seconds, which can be employed to store the digital data in non-volatile memory devices. Thus the voltage controlled magnetization in the nanodot structures leads a path towards the invention of energy efficient high-density memory devices.
Pulsatile parallel flow of air and a viscoelastic fluid with multiple characteristic times. An application to mucus in the trachea and the frequency of cough
Authors: de la Guerra Pablo Alberto , Corvera Poiré E 
Published: May 2022

Abstract
We study the dynamics of a binary fluid, where the two fluids are flowing parallel to each other in a cylindrical geometry, and driven by a pulsatile pressure gradient. One of the fluids is a low viscosity Newtonian fluid, the other one is viscoelastic. In order to be able to apply the model to different biofluids, we consider that the viscoelastic fluid has several characteristic times. We characterize the dynamics of the fluids as generalized Darcy’s laws, with linear response functions to pulsatile pressure gradients, whose parameters are coupled for both fluids through the fluid–fluid boundary conditions. We apply our results to the dynamics of mucus and air in the trachea and find that the frequency that allows for a larger movement of the mucus, coincides with the experimental frequency of cough. This allows us to propose a plausible explanation for the frequency of cough in healthy individuals, a mechanical process to expel noxious substances from the respiratory system.
Practical application of international recommendations and safety standards in the systematic planning and implementation of remediation of sites or areas with residual radioactive material
Authors: Yankovich T L , Roberts M , Brown J , Mori Y , Williams G A , Charalambous F , Pepin S 
Published: May 2022

Abstract
The IAEA fundamental safety objective is ‘to protect people and the environment from harmful effects of ionizing radiation’ and this must be done ‘without unduly limiting the operation of facilities or the conduct of activities that give rise to radiation risks’, while ensuring that people and the environment, present and future are protected against radiation risks (IAEA 2006 Fundamental Safety Principles, Safety Fundamentals No. SF-1). In addition, ‘protective actions to reduce existing or unregulated radiation risks must be justified and optimized’ (IAEA 2006 Fundamental Safety Principles, Safety Fundamentals No. SF-1). An international system of radiological protection can be applied such that processes, such as remediation, can be systematically undertaken to address the wide range of ‘existing exposure situations’ present globally. In doing so, decisions made regarding actions undertaken can be demonstrated to be ‘justified’ and ‘optimized’ (i.e. balanced), such that the amount of effort should be commensurate with the risk (applying a ’graded approach’). In addition, protection of people and the environment can be demonstrated by comparing the actual exposure to appropriate criteria over the lifetime of remediation. This paper provides an overview of the current IAEA safety standards on remediation of sites or areas contaminated with residual radioactive material within the international system of radiological protection and provides practical examples of their application through case studies considered in IAEA international model validation programs.
Extensional study of optical-flow enhanced hybrid PIV method for dual-plane stereoscopic PIV measurement
Authors: Wang Sirui , Zheng Jianyi , Li Lei , Xia Xi , Han Xiao , Zhang Chi , Qi Fei , Yang Zifeng 
Published: May 2022

Abstract
High-speed dual-plane stereoscopic particle image velocimetry (DP-s-PIV) can capture time-resolved three-component velocity and vorticity vectors in the measurement region, but its spatial resolvability of tiny vortices is blocked by the intrinsic limitation of the cross-correlation evaluation. To overcome this limitation, we propose a scheme to extend the original two-component optical-flow enhanced hybrid PIV method to DP-s-PIV through 3D reconstruction, with its feasibility and resolvability validated through comparison with the cross-correlation evaluation used in DaVis 8.4. The comparisons suggest that the optical-flow enhanced hybrid PIV scheme can greatly improve the spatial resolvability of the velocity field for DP-s-PIV. Moreover, the hybrid scheme can also provide better visualization of vortical structures and enhanced precision in evaluating the vorticity distribution, allowing for further identification of vortex types in a stratified swirling jet flow through the combined criteria (vorticity component and Q criterion).
Tuning electronic, magnetic and catalytic behaviors of biphenylene network by atomic doping
Authors: Ren Kai , Shu Huabing , Huo Wenyi , Cui Zhen , Xu Yujing 
Published: May 2022

Abstract
Recently, a new two-dimensional allotrope of carbon named biphenylene has been experimentally synthesized. First-principles calculations are preformed to investigate the electronic properties of biphenylene and the doping effect is also considered to tune its electronic, magnetic, and catalytic properties. The metallic nature with an n-type Dirac cone is observed in the biphenylene. The magnetism can be induced by Fe, Cl, Cr, and Mn doping. More importantly, the doping position dependence of hydrogen evolution reaction (HER) performance of biphenylene is addressed, which can be significantly improved by atomic doping. In particular, the barrier for HER of Fe doping case is only −0.03 eV, denoting its great potential in HER catalysis.
Single β-Ga2O3 nanowire back-gate field-effect transistor
Authors: Qu Guangming , Xu Siyuan , Liu Lining , Tang Minglei , Wu Songhao , Jia Chunyang , Zhang Xingfei , Song Wurui , Lee Young Jin , Xu Jianlong , Wang Guodong , Ma Yuanxiao , Park Ji-Hyeon , Zhang Yiyun , Yi Xiaoyan , Wang Yeliang , Li Jinmin 
Published: May 2022

Abstract
In this work, a normally-on single-monocrystal β-Ga2O3 nanowire (NW) back-gate field-effect transistor (FET) has been demonstrated by transferring metal-organic chemical vapor deposition-grown β-Ga2O3 NWs on sapphire onto SiO2(300 nm)/p
+-Si substrate. When the gate voltage (V
G) exceeds −14 V, the device is pinched off, with an on/off ratio greater than 108 and a drain leakage current density as low as ∼7.34 fA. The maximum field-effect carrier mobility for these n-doped single β-Ga2O3 NW FETs reaches ∼62.2 cm2 (V s)−1. A prompt degradation in the on/off ratio for these β-Ga2O3 NW back-gate FETs is observed as the operation temperature increased up to 400 K. With strong evidence, the temperature-dependent degradation in the performance is determined by the activation of self-trapped holes and intrinsic vacancy-related defects, both of which would lead to a rapid increase in the channel leakage current at high temperatures.
Investigating the importance of strain-coupling in lead-free 2–2 relaxor/ferroelectric composites with digital image correlation
Authors: Martin Alexander , Maier Juliana G , Streich Friedemann , Kamlah Marc , Webber Kyle G 
Published: May 2022

Abstract
Ceramic–ceramic composite structures are a viable solution to improve the electromechanical response of lead-free ferroelectrics (FEs) through tuning of the local electrical and mechanical fields. The origin of the enhanced properties, however, remains unclear, as many of the possible effects, such as polarization and strain coupling (PSC) as well as interface diffusion, are interrelated and difficult to separate or directly investigate. In this study, we use a custom-built digital image correlation system to directly investigate the influence of strain coupling on 2–2 composites consisting of 0.90Na1/2Bi1/2TiO3–0.06BaTiO3–0.04K0.5Na0.5NbO3 (NBT–6BT–4KNN) and 0.94Na1/2Bi1/2TiO3–0.06BaTiO3 (NBT–6BT) by varying the mechanical interface contacts between end members. Specifically, two model cases were utilized to separate the relative contributions of the PSC mechanisms: (a) electrically connected and (b) mechanically and electrically connected. The local strain gradient was characterized through the thickness of the composite across different layers as well as the interface, where the macroscopic large signal longitudinal and transverse FE response was determined. Experimental results reveal an enhancement of the large signal piezoelectric coefficient

d

33

∗

by approximately 10% from 390 to 440 pm V−1 due to strain coupling.
Investigation of high-energy ultrasonication of RE2BaCuO5(RE = Y, Gd) on the growth and superconducting properties of REBa2Cu3O7−δtop-seeded melt textured bulks
Authors: Pavan Kumar Naik Sugali , Hagiwara Rikako , Ishibashi Shinnosuke , Asano Natsuki , Ogino Hiraku , Ishida Shigeyuki , Koblischka Michael Rudolf , Koblischka-Veneva Anjela , Tsuchiya Yoshinori , Kawashima Kenji , Eisaki Hiroshi , Nishio Taichiro 
Published: May 2022

AbstractRecently, an improvement in the flux pinning performance ofREBa2Cu3O7−δ(REBCO) bulk was achieved employing high energy ultrasonic irradiation (up to 300 W and 60 min) prior to the infiltration-growth process. Here, we demonstrate that a higher ultrasonic power and shorter duration treatment (450 W for 30 min) of theRE2BaCuO5(RE211,RE= Y, Gd) powder produces individual, nanometer-sized and surface damagedRE211 particles (RE211Ultra). We study the growth of YBCO and GdBCO systems via the top-seeded melt-growth method, with the addition of 30 mol% ofRE211Ultra, which were pre-treated by high-energy ultrasonication and compared with the conventional method. Isothermal growth experiments clarified that the addition ofRE211Ultraparticles enables faster and more effective crystal growth via an improved peritectic reaction due to their size in the nanometer range and presence of sharp edges, which are crucial for growing large, single grain bulks ofREBCO. Microstructural investigations by scanning electron microscopy indicated the presence of two differently sizedRE211 inclusions within the bulk GdBCO and YBCO superconductors. All samples showed an onset of superconductivity at ∼92 K or above. Utilizing the effective growth temperature window and the addition ofRE211Ultra, single grain bulks of GdBCO and YBCO were fabricated by the slow-cooling method. The field dependent critical current density (Jc) of the bulk samples usingRE211Ultrawere found to exhibit superior performance over the standard GdBCO/YBCO samples due to significant changes of sample growth and of their microstructures. Here, we discuss various factors affecting the addition ofRE211Ultraon the development of the microstructure, growth of bulk, single grain materials and further, the superconducting properties of differentREBCO superconductors.
Three-dimensional accurate modeling of nematic liquid crystal based dipole unit for reconfigurable reflectarray at 100 GHz
Authors: Geng Jin-Ling , Song Lizhong 
Published: May 2022

Abstract
In this paper, a three-dimensional accurate modeling of nematic liquid crystal (LC) has been presented for the analysis of reconfigurable reflectarray cells based on LC. Both single-dipole and multiple-dipoles constructed on a LC substrate are designed as the reflectarray unit cell. Considering the inhomogeneous and anisotropic effects, the orientation of the LC molecules at each point of the LC layer involved in the unit cell under the external electrostatic field is obtained by the finite difference numerical modeling method. Utilizing the accurate modeling results of LC, the reflection constants of the reflectarray unit cells have been simulated and also have been compared with that of in the conventional model which usually assumes the LC is homogeneous and isotropic (HOMI). The error of phase range of the unit cell between the two models can exceed 45° in the single-resonant unit cell, and is more than 290° in the multi-resonant unit cell, which will seriously affect the practical application. The permittivity of LC in the unit cells under different applied voltages also has been calculated and given. Moreover, the gain radiation pattern of the reflectarray consisting of the proposed LC based double-dipoles unit cell is simulated in two models. The simulation results show that, in the accurate modeling, the gain and scanning angle range of the reflectarray obtained by the HOMI model change significantly because the phase-shift of the same unit cell for the incident wave is greatly different in the two models, which indicates that the HOMI model can no longer meet the needs of the design of LC based multi-dipoles reflectarray. Therefore, the accurate modeling method needs to be considered and cannot be ignored when studying and designing LC based devices.
Exchange-correlation effects in coupled quantum wire systems at finite temperature
Authors: Sharma Akariti , Garg Vinayak , Moudgil R K 
Published: May 2022

Abstract
We investigate the exchange-correlation effects in coupled quantum wire systems at finite-temperature within the self-consistent mean-field approximation of Singwi et al by assuming the charge carriers to be electrons in one wire and electrons or heavier holes in the other. Numerical results are presented for the intra- and inter-wire static structure factors, pair-correlation functions and the static charge density susceptibility over a wide range of system parameters (viz. temperature T, particle number density and inter-wire spacing) at equal and fixed transverse width of both the wires. We find for the first time that the coupled electron-hole (e-h) quantum wire system may favor a charge-density-wave (CDW) instability at sufficiently low T and carrier density in the close proximity of the wires, where as no such phase transition is observed in the electron-electron (e-e) quantum wire system at any non-zero T. The intra-wire contact pair-correlation functions of both the systems show a non-monotonous behavior with increasing (decreasing) T (carrier number density), and increase consistently with decrease in inter-wire spacing. On the other hand, the corresponding inter-wire contact pair-correlation functions show a non-monotonous T-dependence and consistent increase with decrease in carrier number density and/or inter-wire separation. Results of free exchange-correlation energy for both the e-h and e-e coupled systems are also reported which are found to have a noticeable dependence upon T. To highlight the effect of exchange-correlations, our results have been compared with the predictions of the random-phase approximation (RPA).
Surface plasmon polariton at the interface of dielectric and graphene medium using the Doppler broadening effect
Authors: Ahmad Faizan , Bakhtawar  , Haneef Muhammad , Khan Humayun , Abid Aqsa , Dahshan A 
Published: May 2022

Abstract
We theoretically investigate the control of surface plasmon polariton (SPP) generated at the interface of dielectric and graphene due to effective variation of dielectric functions. The input light pulse is controlled and modified in a Doppler broadening dielectric medium. The controlled and modified output, from Doppler broadening dielectric medium is used to excite SPPs at the interface of graphene and dielectric medium. It is noted that at high Doppler width the absorption/dispersion and propagation length of SPPs become saturated and significantly affected by strength of the control fields. The inverse Doppler effect enhances the group speed of SPPs but suddenly decreases at the region of SPPs hole burning. These results have potential applications in optical tweezers, nano-photonics, radiations guiding, plasmonster technology, photovoltaic devices, data storage devices, biosensor technology and solar cells.
Simulating the perceptual effects of electrode–retina distance in prosthetic vision
Authors: Avraham David , Yitzhaky Yitzhak 
Published: May 2022

Abstract

Objective. Retinal prostheses aim to restore some vision in retinitis pigmentosa and age-related macular degeneration blind patients. Many spatial and temporal aspects have been found to affect prosthetic vision. Our objective is to study the impact of the space-variant distance between the stimulating electrodes and the surface of the retina on prosthetic vision and how to mitigate this impact. Approach. A prosthetic vision simulation was built to demonstrate the perceptual effects of the electrode–retina distance (ERD) with different random spatial variations, such as size, brightness, shape, dropout, and spatial shifts. Three approaches for reducing the ERD effects are demonstrated: electrode grouping (quads), ERD-based input-image enhancement, and object scanning with and without phosphene persistence. A quantitative assessment for the first two approaches was done based on experiments with 20 subjects and three vision-based computational image similarity metrics. Main results. The effects of various ERDs on phosphenes’ size, brightness, and shape were simulated. Quads, chosen according to the ERDs, effectively elicit phosphenes without exceeding the safe charge density limit, whereas single electrodes with large ERD cannot do so. Input-image enhancement reduced the ERD effects effectively. These two approaches significantly improved ERD-affected prosthetic vision according to the experiment and image similarity metrics. A further reduction of the ERD effects was achieved by scanning an object while moving the head. Significance. ERD has multiple effects on perception with retinal prostheses. One of them is vision loss caused by the incapability of electrodes with large ERD to evoke phosphenes. The three approaches presented in this study can be used separately or together to mitigate the impact of ERD. A consideration of our approaches in reducing the perceptual effects of the ERD may help improve the perception with current prosthetic technology and influence the design of future prostheses.
Studies of energetic particle transport induced by multiple Alfvén eigenmodes using neutron and escaping energetic particle diagnostics in Large Helical Device deuterium plasmas
Authors: Ogawa K. , Isobe M. , Kamio S. , Nuga H. , Seki R. , Sangaroon S. , Yamaguchi H. , Fujiwara Y. , Takada E. , Murakami S. , Jo J. , Takemura Y. , Sakai H. , Tanaka K. , Tokuzawa T. , Yasuhara R. , Osakabe M. 
Published: May 2022

Abstract
Studies of energetic particle transport due to energetic-particle-driven Alfvénic instability have progressed using neutron and energetic particle diagnostics in Large Helical Device deuterium plasmas. Alfvénic instability excited by injecting an intensive neutral beam was observed by a magnetic probe and a far-infrared laser interferometer. The interferometer showed Alfvénic instability composed of three modes that existed from the core to the edge of the plasma. A comparison between the observed frequency and shear Alfvén spectra suggested that the mode activity was most likely classified as an Alfvénic avalanche. A neutron fluctuation detector and a fast ion loss detector indicated that Alfvénic instability induced transport and loss of co-going transit energetic ions. The dependence of the drop rate of the neutron signal on the Alfvénic instability amplitude showed that significant transport occurred. Significant transport might be induced by the large amplitude and radially extended multiple modes, as well as a large deviation of the energetic ion orbit from the flux surface.
Upgrade of a quasioptical code PARADE for fusion DEMO: introducing relativistic electron dynamics
Authors: Yanagihara K. 
Published: May 2022

Abstract
Here we report on the upgrade of the quasioptical code PAraxial RAy DEscription (2019 Phys. Plasmas
26 072112) to introduce the relativistic effect for electron cyclotron resonance heating and current drive on fusion DEMO reactors, e.g. JA-DEMO, where the electron temperature is sufficiently high (almost 35 keV). By fully considering the relativistic effect, it is found that the outside launch used in many tokamaks is not suitable for localized heating in JA-DEMOdue to the contamination of spatially widespread absorption at relativistically down-shifted higher-harmonic resonance. It is proposed to adopt a top launch to avoid this issue, and is shown that top launch can improve the localization of the heating without degrading the current drive efficiency.