bluuebunny/crossref_metadata_2025_split huggingface dataset:
The origin of Weyl gauging in metric-affine theories
Authors: Sauro Dario , Zanusso Omar 
Published: July 2022

Abstract
In the first part, we discuss the interplay between local scale invariance and metric-affine degrees of freedom from few distinct points of view. We argue, rather generally, that the gauging of Weyl symmetry is a natural byproduct of requiring that scale invariance is a symmetry of a gravitational theory that is based on a metric and on an independent affine structure degrees of freedom. In the second part, we compute the Nöther identities associated with all the gauge symmetries, including Weyl, Lorentz and diffeomorphisms invariances, for general actions with matter degrees of freedom, exploiting a gauge covariant generalization of the Lie derivative. We find two equivalent ways to approach the problem, based on how we regard the spin-connection degrees of freedom, either as an independent object or as the sum of two Weyl invariant terms. The latter approach, which rests upon the use of a Weyl-covariant connection with desirable properties, denoted

∇

^

, is particularly convenient and constitutes one of our main results.
An A0 mode Lamb-wave AlN resonator on SOI substrate with vertically arranged double-electrodes
Authors: Cao Haichao , Lu Xianzheng , Ren Hao 
Published: July 2022

Abstract
In this paper, a novel vertically arranged double-electrodes A0 mode Lamb-wave AlN resonator on SOI substrate with a high electromechanical coupling coefficient and high figure of merit (FOM) is reported. The AlN resonator has a sandwich structure with aluminum and N-type doped silicon as electrode layers and a 500 nm thick AlN film as piezoelectric layer. The resonator has only two electrodes vertically arranged rather than horizontal interdigitated (IDT) electrodes which is common in conventional Lamb-wave resonators. The electrode gaps for the vertically arranged double-electrodes resonators are defined by AlN layer thickness rather than by photolithography for lateral field excitation resonators, which results in higher electric field strength and higher electromechanical coupling efficient (

k

t

2

). Compared with conventional thickness field excitation (TFE) resonators with floating bottom electrodes, the vertically arranged double-electrodes resonators have higher electric field strength as the potential difference is larger between the top electrode and bottom electrode than that between the IDT electrodes and floating electrode. As a result, a higher electromechanical coupling coefficient is achieved. Furthermore, the resonant frequency of the vertically arranged double-electrodes resonator presented in this work can be defined by photolithography by controlling the width of the silicon layer. The

k

t

2

of the vertically arranged double-electrodes resonator calculated from the measurement results of admittance versus frequency by numerically fitting with the Butterworth Van Dyke model shows an increase by 3.85 times, from 0.073% to 0.281% compared with conventional TFE resonators, and the FOM also increases by three times, from 2.66 to 7.99. This work provides a new structure to design future AlN Lamb-wave resonators on SOI substrate.
Self-consistent fractal geometry in polyampholyte hydrogels undergoing exchange and correlation charge-density
Authors: Xing Ziyu , Lu Haibao , Fu Yong-Qing 
Published: July 2022

Abstract
Polyampholyte (PA) hydrogels are incorporated of many internally charged polymer chains, which play an important role to influence the fractal networks and dynamic elasticity of the PA hydrogels owing to their different exchange and correlation charge-densities. Many properties of the PA hydrogels, such as mechanical strength and deformation, are significantly dependent on their fractal networks. However, working principles of chemo-mechanical coupling between the fractal networks and the elasticity of PA hydrogels have not been fully understood. In this study, a self-consistent fractal geometry model integrated with a complex function is proposed to understand the constitutive relationship between dynamic networks and tailorable mechanics in the PA hydrogels. The newly developed model is uniquely incorporated with the mechanochemistry, and describes the chemical polarization reactions of charged networks and their mechanical behaviors using complex fractal functions. Based on the rubber elasticity theory, constitutive stress–strain relationships of fractal networks have been described using their elastic, conformational, repulsive and polarization free-energy functions. Finally, effectiveness of the proposed model has been verified using both finite element analysis and experimental results of the PA hydrogels reported in literature.
An effective method to enhance the underwater sound absorption performance by constructing a membrane-type acoustic metamaterial
Authors: Sun Yingjian , Yuan Xujin , Jin Zhongkun , Hong Guangfu , Chen Mingji , Zhou Mengjing , Li Weiduan , Fang Daining 
Published: July 2022

Abstract
Broadband sound absorption has consistently been a challenge in designing underwater sound absorption structure (USAS). Most research of USASs achieve broadband sound absorption through structural optimization, which curbs the freedom of designing, and commonly alights it at the expense of increased thickness. In this paper, a method is reported to broaden the frequency band of the USAS by embedding a membrane-type resonator into the cavity, which forming a membrane-type underwater acoustic absorption metamaterial. We demonstrate the mechanism of membrane-type metamaterial by theory, and verify it by simulation and experiment. The experimental results show that the sound absorption coefficient in the frequency range of 2000–10 000 Hz is significantly improved after implanting the membrane-type resonator into the cavity. The average sound absorption coefficient is increased by nearly 17%, and the improvement effect of the sound absorption covers to each frequency point, which is consistent with our expectation. As the case of applying membrane-type metamaterials to the design process of underwater acoustic structures, this research possesses great application potential in acoustic wave communication and device compatibility design technologies.
DFT-1/2 and shell DFT-1/2 methods: electronic structure calculation for semiconductors at LDA complexity
Authors: Mao Ge-Qi , Yan Zhao-Yi , Xue Kan-Hao , Ai Zhengwei , Yang Shengxin , Cui Hanli , Yuan Jun-Hui , Ren Tian-Ling , Miao Xiangshui 
Published: July 2022

Abstract
It is known that the Kohn–Sham eigenvalues do not characterize experimental excitation energies directly, and the band gap of a semiconductor is typically underestimated by local density approximation (LDA) of density functional theory (DFT). An embarrassing situation is that one usually uses LDA+U for strongly correlated materials with rectified band gaps, but for non-strongly-correlated semiconductors one has to resort to expensive methods like hybrid functionals or GW. In spite of the state-of-the-art meta-generalized gradient approximation functionals like TB-mBJ and SCAN, methods with LDA-level complexity to rectify the semiconductor band gaps are in high demand. DFT-1/2 stands as a feasible approach and has been more widely used in recent years. In this work we give a detailed derivation of the Slater half occupation technique, and review the assumptions made by DFT-1/2 in semiconductor band structure calculations. In particular, the self-energy potential approach is verified through mathematical derivations. The aims, features and principles of shell DFT-1/2 for covalent semiconductors are also accounted for in great detail. Other developments of DFT-1/2 including conduction band correction, DFT+A-1/2, empirical formula for the self-energy potential cutoff radius, etc, are further reviewed. The relations of DFT-1/2 to hybrid functional, sX-LDA, GW, self-interaction correction, scissor’s operator as well as DFT+U are explained. Applications, issues and limitations of DFT-1/2 are comprehensively included in this review.
A combined velocity and temperature measurement with an LED and a low-speed camera
Authors: Deng Zhichao , König Jörg , Cierpka Christian 
Published: July 2022

Abstract
Microfluidic devices are governed by three-dimensional velocity and temperature fields, and their boundary conditions are often unknown. Therefore, a measurement technique is often desired to measure both fields in a volume. With astigmatism particle tracking velocimetry (APTV) combined with luminescence lifetime imaging, the temperature and all velocity components in a volume can be measured with one optical access. While the three-dimensional particle position is determined by evaluating the shape of the corresponding particle image, the temperature measurement relies on estimating the temperature-dependent luminescence lifetime derived from particle images on two subsequent image captures shortly after the photoexcitation. For this, typically a high-energetic pulsed laser is required to ensure a high signal-to-noise ratio. However, it can also cause additional heating of the fluid. We show that this problem is solved by replacing the pulsed laser with an LED. To compensate for the lower power provided by the LED, we adapted the timing schedule and vastly extended the illumination time and the exposure time for both image captures. In addition, we were able to replace the typically used high-speed camera with an ordinary double-frame camera. In this way, very low measurement uncertainties on all measured quantities can be achieved while keeping the temperature of the fluid unaffected. Random errors dominate within the two focal planes of APTV, yielding a standard deviation of the temperature of individual particles of about 1

∘

C

only. The measurement error caused by the movement of tracer particles during the much longer illumination and exposure time were found to be acceptable when the measured velocity is low. With the circumvention of light-source induced heating and the lower cost of hardware devices, the adapted approach is a suitable measurement technique for microfluidic related research.
An accurate orientation measurement system of self-propelled artillery barrel based on coordinate system mapping
Authors: Cheng Zejun , Wang Huaiguang , Han Lanyi , Du Binhan , Shi Zhiyong 
Published: July 2022

Abstract
Barrel orientation accuracy is an essential factor affecting the hit rate of self-propelled artillery, which comprehensively reflects the working state of the self-propelled artillery fire control system. An accurate self-propelled artillery orientation measurement system based on the coordinate system mapping is proposed to reduce the axis simulation error and introduce the north datum. The measurement system uses Radio Navigation Satellite System orientation technology to determine the measurement area’s standard north orientation. Based on the standard north orientation, a coordinate measurement system is established. The total station and self-propelled artillery positions are unified to the coordinate measurement system. The total station measures the coordinates of the marked points on the barrel. According to the coordinates of the marker points under different datums, the mapping relationship of different coordinate systems can be obtained. The total station measures the azimuth and elevation angle of the line connecting the marked points. Based on the coordinate system mapping relationship, the accurate orientation of the self-propelled artillery barrel can be calculated. The combined standard uncertainty evaluation is performed, and the uncertainties of the azimuth and elevation angles are

1.5167
×

10

−
4

rad

and

1.6341
×

10

−
4

rad

, respectively. A particular type of self-propelled artillery is selected for experiments. The results show that the system’s measurement accuracy can be guaranteed within

2.0944
×

10

−
4

rad

.
On the non-chiral intermediate long wave equation
Authors: Berntson Bjorn K , Langmann Edwin , Lenells Jonatan 
Published: July 2022

Abstract
We study integrability properties of the non-chiral intermediate long wave equation recently introduced by the authors as a parity-invariant variant of the intermediate long wave equation. For this new equation we: (a) derive a Lax pair, (b) derive a Hirota bilinear form, (c) derive a Bäcklund transformation, (d) use, separately, the Bäcklund transformation and the Lax representation to obtain an infinite number of conservation laws.
Extraction of quasi-coherent modes based on reflectometry data
Authors: Salazar Luigui , Heuraux Stéphane , Sabot Roland , Krämer-Flecken Andreas , Supra Team Tore 
Published: July 2022

Abstract
The identification of turbulence sources would drive to a deeper understanding of confinement dynamics in tokamak plasmas. Turbulence results from a mixture of instabilities corresponding to sources at different timescales and spatial scales. Using poloidal correlation reflectometry and multi-pin Langmuir probe, it was shown in the T-10 and the Tokamak Experiment for Technology Oriented Research (TEXTOR) tokamaks that the reflectometry frequency spectrum is the superposition of several components: broadband component, quasi-coherent (QC) modes and low-frequency components. The relevance of QC modes is associated with their link with the trapped electron mode instability. This link was exhibited in the transition from the linear ohmic confinement (LOC) to the saturated ohmic confinement (SOC) regime. A method is presented in this paper to extract the QC mode component from the reflectometry data, enabling its separation from the broadband component and the study of its time evolution. It is a first step toward the discrimination of turbulence sources. The central idea explores a way to combine the approach of signal processing and machine learning. The continuous wavelet transform on the basis of complex Morlet wavelet has proved to be efficient in providing a decomposition of a signal at different scales over time for fluctuation tackling; clustering techniques, such as the mini-batch K-means, are able to tackle clusters at different scales. The method was applied to Tore Supra and TEXTOR reflectometry data. In Tore Supra, the amplitude of the extracted QC mode component decreases during the LOC–SOC transition. In TEXTOR, the amplitude of the coherent spectra of the extracted QC mode component is similar to the experimental coherent spectra obtained through correlation reflectometry. The developed method permits the extraction of components, preserving their physical and statistical properties.
Effects of ICRF waves to EAST LHCD discharges on intrinsic rotations
Authors: Jin Y F , Lyu B , Bae C , Zhang X J , Rice J E , Wang F D , Fu J , Liu H Q , Zhang H M , Zeng L , Chu Y Q , Zang Q , Bin B , Li Y C , He L , Lu D A , Liu H J 
Published: July 2022

Abstract
Ion cyclotron range of frequencies (ICRFs) have proven to efficiently serve as a toroidal rotation source in tokamak plasmas. Recent experiments on the experimental advanced superconducting tokamak show that the rotation profiles are remarkably modified when the internal inductance (l
i) changed. The comparisons of the ion and electron temperature profiles among ICRF-heated plasmas suggest that the change in l
i can remarkably affect the toroidal rotation velocity. The scaling of rotation velocity increments as a function of the change in l
i also suggests that ICRF would serve as a reliable rotation source in plasmas with larger l
i decrements.
Charged-particles measurements in low-pressure iodine plasmas used for electric propulsion
Authors: Esteves B , Marmuse F , Drag C , Bourdon A , Laguna A Alvarez , Chabert P 
Published: July 2022

Abstract
This paper investigates iodine as an alternative propellant for space plasma propulsion. Measurements are taken in a low-pressure inductively-coupled plasma chamber used as the ionization stage of a gridded ion-engine. Langmuir probes are used to measure the electron density and the electron energy distribution functions spatial variations between the inductive coil and the extraction grids for several radio-frequency (RF) powers and mass flow rates. Measurements in iodine are compared to xenon, krypton and argon in order to evaluate performances of these various propellants for ionization (and therefore power) efficiency. At low mass flow rates, iodine is found to be the most efficient propellant, however, as the mass flow rate increases, the ionization cost in iodine increases rapidly due to both its molecular and electronegative nature. The ratio of negative ion to electron density is measured using laser-induced photodetachment in order to quantify the effect of iodine electronegativity. Finally, all measurements are compared to a previously published global (volume-averaged) model. The agreement between model and experiments is acceptable, however several modelling improvements are proposed.
Experimental characterization of the thermo-electro-mechanical properties of a shape memory composite during electric activation
Authors: Pereira Sánchez Clara , Houbben Maxime , Fagnard Jean-Francois , Harmeling Pascal , Jérôme Christine , Noels Ludovic , Vanderbemden Philippe 
Published: July 2022

Abstract
This works investigates in detail the electro-thermo-mechanical properties of a shape memory composite (SMC) during shape memory cycles in which the heating is a result of resistive heating. The SMC is a covalently cross-linked poly(ϵ-caprolactone) network filled with 3 wt% of multiwall carbon nanotubes. The characterization is performed with the help of a custom-made tensile test bench that is able to couple the mechanical characterization with the thermal and electrical ones. A proportional integral controller using the lambda tuning method is used in order to control the temperature achieved by resistive heating of the SMC. The electrical resistivity of the SMC shows a non-linear and non-monotonic dependence on temperature and strain. The resistivity is also found to vary among successive shape memory cycles, suggesting that a (first) training cycle is necessary not only to stabilize the mechanical but also the electrical properties of the SMC. A fuzzy logic controller for constant load control is also used to investigate the strain variation with temperature related to the two-way shape memory effect of the SMC. The results give evidence of the strong interplay between the electrical and (thermo-)mechanical characteristics of electroactive SMCs.
Efficient and robust entanglement generation with deep reinforcement learning for quantum metrology
Authors: Qiu Yuxiang , Zhuang Min , Huang Jiahao , Lee Chaohong 
Published: July 2022

Abstract
Quantum metrology exploits quantum resources and strategies to improve measurement precision of unknown parameters. One crucial issue is how to prepare a quantum entangled state suitable for high-precision measurement beyond the standard quantum limit. Here, we propose a scheme to optimize the state preparation pulse sequence to accelerate the one-axis twisting dynamics for entanglement generation with the aid of deep reinforcement learning (DRL). We consider the pulse train as a sequence of π/2 pulses along one axis or two orthogonal axes, and the operation is determined by maximizing the quantum Fisher information using DRL. Within a limited evolution time, the ultimate precision bounds of the prepared entangled states follow the Heisenberg-limited scalings. These states can also be used as the input states for Ramsey interferometry and the final measurement precisions still follow the Heisenberg-limited scalings. While the pulse train along only one axis is more simple and efficient, the scheme using pulse sequence along two orthogonal axes show better robustness against atom number difference between simulation and experiment. Our protocol with DRL is efficient and easy to be implemented in state-of-the-art experiments.
Structural role of double layer amphoteric oxides forms on electrical conductivity: PbO/zinc oxide semiconductor
Authors: Akay Defne , Gökmen Uğur , Ocak Sema Bilge 
Published: July 2022

AbstractWe have investigated the electrical properties of PbO/Zinc Oxide double-layer semiconductor (DLS) diodes such as series resistance (Rs), ideality factor (n), and barrier height (φb). The samples were manufactured by using an evaporation technique at room temperature. To obtain their main electrical parameters, current-voltage (I–V) measurements have been performed in the dark and at room temperature. In the study, we examined two diodes to evaluate the electrical characteristics of PbO/Zinc Oxide double-layer semiconductor (DLS) diodes using the thermionic emission (TE) theory, Norde’s method, and Cheung’s functions. While n,ϕb,andI0values of Diode 1 were found to be 4.02, 0.739 eV, and 1.506. 10−8A respectively, the same values of Diode 2 were calculated as 4.14, 0.724 eV, and 2.65.10−8A, respectively, by using the TE method. The values of n,ϕb,andRswere also calculated using the Cheung’s method, and they were found to be 10.048, 0.549 eV, and 4.058kΩ,respectively, for Diode 1, while these values were calculated as 8.116, 0.659 eV, and 7.799kΩrespectively, for Diode 2.φbandRsvalues are also ascertained as0.84eVfor Diode 1 and0.80eVfor Diode 2,18.2kΩfor Diode 1 and11.1kΩfor Diode 2 using Norde Method, respectively. The forward bias I–V characteristics were used to obtain the energy distribution of the interface state density considering the effective barrier height’s bias dependence. The change observed in the interface state density’s magnitude ranged between1.4×1012and2.0×1011eV−1cm−2.The evaluated series resistance indicates the product of mobility and free carrier concentration, ideality factor is a measure of how closely the diode follows the ideal diode equation, and barrier height also depends on the concentration of carriers in PbO/Zinc Oxide double-layer semiconductors.
Characterizing spatial point processes by percolation transitions
Authors: Villegas Pablo , Gili Tommaso , Gabrielli Andrea , Caldarelli Guido 
Published: July 2022

Abstract
A set of discrete individual points located in an embedding continuum space can be seen as percolating or non-percolating, depending on the radius of the discs/spheres associated with each of them. This problem is relevant in theoretical ecology to analyze, e.g., the spatial percolation of a tree species in a tropical forest or a savanna. Here, we revisit the problem of aggregating random points in continuum systems (from 2 to 6-dimensional Euclidean spaces) to analyze the nature of the corresponding percolation transition in spatial point processes. This problem finds a natural description in terms of the canonical ensemble but not in the usual grand-canonical one, customarily employed to describe percolation transitions. This leads us to analyze the question of ensemble equivalence and study whether the resulting canonical continuum percolation transition shares its universal properties with standard percolation transitions, analyzing diverse homogeneous and heterogeneous spatial point processes. We, therefore, provide a powerful tool to characterize and classify a vast class of natural point patterns, revealing their fundamental properties based on percolation phase transitions.
Spherical model with Dzyaloshinskii–Moriya interactions
Authors: de Castilho William , Salinas S R 
Published: July 2022

Abstract
We analyze the thermodynamic behavior of a ferromagnetic mean-spherical model with three distinct spin components and the addition of Dzyaloshinkii–Moriya interactions. Exact calculations are performed for classical and quantum versions of this lattice model system. We show the onset of space modulated structures at low temperatures.