bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electric field modulated electronic, thermoelectric and transport properties of 2D tetragonal silicene and its nanoribbons
Authors: Mondal Niladri Sekhar , Mondal Rajkumar , Bedamani Singh N , Nath Subhadip , Jana Debnarayan 
Published: June 2024

Abstract
Using both first principles and analytical approaches, we investigate the role of a transverse electric field in tuning the electrical, thermoelectric, optical and transport properties of a buckled tetragonal silicene (TS) structure. The transverse electric field transforms the linear spectrum to parabolic at the Fermi level and opens a band gap. The gap is similar at the two Dirac points present in the irreducible Brillouin zone of the TS structure and increases in proportion to the applied field strength. However, a sufficiently strong electric field converts the system into a metallic one. A comparable band opening is also seen in the TS nanoribbons. Electric field-induced semiconducting nature improves its thermoelectric properties. Estimated Debye temperature reveals its superiority over graphene in terms of thermoelectric performance. The optical response of the structures is very asymmetric. Large values of imaginary and real components of the dielectric function are seen. The absorption frequency lies in the UV region. Plasma frequencies are identified and are red-shifted with the applied field. The current–voltage characteristics of the symmetric type nanoribbons show oscillation in current whereas the voltage-rectifying capability of anti-symmetric type nanoribbons under a transverse electric field is interesting.
Well-posedness of the periodic dispersion-generalized Benjamin–Ono equation in the weakly dispersive regime
Authors: Jöckel Niklas 
Published: June 2024

Abstract
We study the dispersion-generalized Benjamin–Ono equation in the periodic setting. This equation interpolates between the Benjamin–Ono equation (

α
=
1

) and the inviscid Burgers’ equation (

α
=
0

). We obtain local well-posedness in

H
s

(

T

)

for

s
>

3
2

−
α

and

α
∈
(
0
,
1
)

by using the short-time Fourier restriction method.
Scattering of solutions with group invariance for the fourth-order nonlinear Schrödinger equation
Authors: Komada Koichi , Masaki Satoshi 
Published: June 2024

Abstract
In this paper, we consider the focusing, L
2-supercritical and

H
˙

2

-subcritical fourth-order nonlinear Schrödinger equations. We show the scattering of group-invariant solutions below the ground state threshold, under the hypothesis that the threshold for group-invariant solutions is less than a certain value.
A cylindrical shell comprising multifunctional metamaterial cores with ultra-low frequency vibroacoustic reduction and mechanical performances
Authors: Jia Qi , Yu Dianlong , Fang Xin , Zhao Honggang , Wen Jihong 
Published: June 2024

Abstract
Deep-sea submersible is an important part of oceanic equipment, where special operating environment must require the outer material to have multifunctional properties such as load-bearing, buckling, and vibroacoustic suppression. Here, we proposed a novel metamaterial with excellent mechanical and ultra-low frequency vibroacoustic characteristics as a core material for cylindrical shells used in deep-sea submersibles. Compared to honeycomb materials, the proposed metamaterial utilized the design principles of local resonance theory, incorporating a subwavelength structure periodically embedded within the porous honeycomb structure. This configuration was expected to result in superior static and dynamic properties. Then, we systematically discussed the mechanical and vibroacoustic performance of sandwich cylindrical shells with metamaterial cores, characterized by positive or negative Poisson's ratios, to explore their potential for engineering applications in submerged pressure-resistant structures. The respective unit cells were designed to have equivalent load-bearing capabilities, and simulations were conducted to analyze the physical characteristics related to pressure resistance, buckling, and wave reduction. The results indicated that, compared to conventional honeycomb structures, the metamaterials based on PMMA could safely withstand hydrostatic pressures of nearly 7 MPa, resulting in nearly a twofold increase in structural strength. Additionally, the proposed metamaterials could open bandgaps in an ultra-low frequency range (with the normalized frequency Ω as low as 0.013) and an ultra-wide frequency range (with the bandwidth ratio as high as 83.50%), attributable to the coupling effect of traveling waves and subwavelength units. It is worth noting that the robustness and hydrostatic pressure insensitivity of the metamaterial were demonstrated in the studied hydrostatic pressure range of 0.1 MPa to 5 MPa. This work verified the feasibility of coupling the design between local resonance theory and porous structures, and provided guidance for the multifunctional design of sandwich cylindrical shells.
Empirical adequacy of the time operator canonically conjugate to a Hamiltonian generating translations
Authors: Stoica Ovidiu Cristinel 
Published: June 2024

Abstract
To admit a canonically conjugate time operator, the Hamiltonian has to be a generator of translations (like the momentum operator generates translations in space), so its spectrum must be unbounded. But the Hamiltonian governing our world is thought to be bounded from below. Also, judging by the number of fields and parameters of the Standard Model, the Hamiltonian seems much more complicated. In this article I give examples of worlds governed by Hamiltonians generating translations. They can be expressed as a partial derivative operator just like the momentum operator, but when expressed in function of other observables they can exhibit any level of complexity. The examples include any quantum world realizing a standard ideal measurement, any quantum world containing a clock or a free massless fermion, the quantum representation of any deterministic time-reversible dynamical system without time loops, and any quantum world that cannot return to a past state. Such worlds are as sophisticated as our world, but they admit a time operator. I show that, despite having unbounded Hamiltonian, they do not decay to infinite negative energy any more than any quantum or classical world. Since two such quantum systems of the same Hilbert space dimension are unitarily equivalent even if the physical content of their observables is very different, they are concrete counterexamples to Hilbert Space Fundamentalism (HSF). Taking the observables into account removes the ambiguity of HSF and the clock ambiguity problem attributed to the Page-Wootters formalism, also caused by assuming HSF. These results provide additional motivations to restore the spacetime symmetry in the formulation of Quantum Mechanics and for the Page-Wootters formalism.
Nature of the bond in intermetallic compounds
Authors: Thankappan Pillai Rajasekharan , Vummethala Seshu Bai 
Published: June 2024

Abstract
By studying 398 binary compounds crystallizing in five different crystal structures, it is shown that atomic radii of the elements

R

A

and

R

B

change to reach a constant radius ratio

r

A

/

r

B

(
≡
ϒ
)

in a cubic system. In systems of lower symmetry, a range of ϒ values, each corresponding to a certain axial ratio, is possible. Accurate charge values on atoms in solids are derived from the experimental internal radii

r

A

and

r

B

,

using Shannon’s compilation of radii versus charge states for elements. It is found, for the first time, that charge transfer and radii change reverse their direction at the

ϒ

point. Electronegativity difference relative to its value at the ϒ point is recognized to correctly predict the charge transfer and radii changes with

R

A

/

R

B

.

The deduced electronic structure of solids, based on spherical ions carrying partial charges, confirms that the metallic atom-pair bond is a resonating polar covalent bond. Identification of the number of electrons that contribute to cohesion and electrical conduction individually, allows successful prediction of electrical conductivity variation for transition metals and p-elements in the periodic table. From a knowledge of accurate valence of elements and of charge on the atoms, variation in the 197Au isomer shift of the gold compounds of CsCl type structure is predicted. The charges on atoms computed using the Quantum Theory of Atoms in Molecules (QTAIM) technique agree with those obtained in our work for compounds belonging to two of the structure types. For compounds belonging to the other three, the charge values obtained by the two methods do not agree. The disagreement correlates to not reckoning the role of the ϒ point. The effect of ϒ point is so fundamental and universal that most physical properties obtained by the secondary processing of primary DFT data, can be influenced by it.
An innovative treatment of anharmonic and Morse potentials to determine the spectroscopic constants of diatomic molecules
Authors: Amila I , Fedoul A , Janati Idrissi M , Chatwiti A , Sayouri S 
Published: June 2024

Abstract
In this work, we develop an operational method to determine the explicit expressions of the spectroscopic constants ω

e
, ω

e

x

e
, ω

e

y

e
, and ω

e

z

e
of diatomic systems using the solutions of the Schrödinger equation up to the second order of polynomial anharmonic and Morse potentials with the help of the Floquet theorem combined with the resonating average method. As an example, we performed numerical calculations of the above-mentioned constants for H2, LiH, CO, and NO molecules. We present and discuss our results compared to those of other authors available in the literature.
Velocity inversion of a relativistic electron incident by a vortex beam in a magnetic field
Authors: Shi Yu , Li Haiying , Bai Lu , Xu Bin , Tong Jiachen , Wu Songyang 
Published: June 2024

Abstract
A method is proposed to invert the velocity of a relativistic electron incident by a vector Bessel vortex beam in a magnetic field by analyzing the spectra of the backward scattered echoes. The scattering power and spectra are investigated based on the vector plane wave angular spectrum theory and the Thomson scattering theory. The results indicate that the high velocity of an electron causes the distribution of the scattered power on the

x
o
y

plane to shift in the direction of the velocity. Additionally, the spectra of the scattered echoes display periodic bimodality due to the cyclotron motion of the electrons. The velocity of a relativistic electron parallel to the applied magnetic field can be obtained from the spectrum of the scattered echoes and the parameters of the vortex beam. The conclusions suggest that both the magnitude and the direction of the velocity of a relativistic electron can be determined using a set of orthogonal magnetic fields. This work is significant for studying the scattering of vortex beams by plasmas and developing diagnostic techniques of plasmas.
Fast and spurious: a robust determination of our peculiar velocity with future galaxy surveys
Authors: Lacasa Fabien , Bonvin Camille , Dalang Charles , Durrer Ruth 
Published: June 2024

AbstractTo date, the most precise measurement of the observer's peculiar velocity comes from the dipole in the Cosmic Microwave Background (CMB). This velocity also generates a dipole in the source number counts, whose amplitude is governed not only by the observer velocity, but also by specific properties of the sources, that are difficult to determine precisely. Quantitative studies of the source number counts currently give dipoles which are reasonably well aligned with the CMB dipole, but with a significantly larger amplitude than that of the CMB dipole. In this work, we explore an alternative way of measuring the observer velocity from the source number counts, using correlations between neighboring spherical harmonic coefficients, induced by the velocity. We show that these correlations contain both a term sensitive to the source properties and another one directly given by the observer velocity. We explore the potential of aEuclid-like survey to directly measure this second contribution, independently of the characteristics of the population of sources. We find that the method can reach a precision of 4%, corresponding to a detection significance of 24σ, on the observer velocity. This will settle with precision the present “dipole tension”.
Singlet Dirac dark matter streamlined
Authors: Yaguna Carlos E. , Zapata Óscar 
Published: June 2024

Abstract
We propose a new and compact realization of singlet Dirac dark matter within the WIMP framework. Our model replaces the standard Z
2 stabilizing symmetry with a Z
6, and uses spontaneous symmetry breaking to generate the dark matter mass, resulting in a much simplified scenario for Dirac dark matter. Concretely, we extend the Standard Model (SM) with just two new particles, a Dirac fermion (the dark matter) and a real scalar, both charged under the Z
6 symmetry. After acquiring a vacuum expectation value, the scalar gives mass to the dark matter and mixes with the Higgs boson, providing the link between the dark sector and the SM particles. With only four free parameters, this new model is extremely simple and predictive. We study the dark matter density as a function of the model's free parameters and use a likelihood approach to determine its viable parameter space. Our results demonstrate that the dark matter mass can be as large as 6 TeV while remaining consistent with all known theoretical and experimental bounds. In addition, a large fraction of viable models turns out to lie within the sensitivity of future direct detection experiments, furnishing a promising way to test this appealing scenario.
First observation of edge impurity behavior with n = 1 RMP application in EAST L-mode plasma
Authors: Zhang Wenmin , Zhang Ling , Cheng Yunxin , Morita Shigeru , Sheng Hui , Mitnik Darío , Sun Youwen , Wang Zhengxiong , Chu Yuqi , Hu Ailan , Jie Yinxian , Liu Haiqing 
Published: June 2024

Abstract
High-Z impurity accumulation suppression and mitigation in core plasma is frequently observed in EAST edge localized mode mitigation experiments by using resonant magnetic perturbations (RMP) coils. To study the individual effects of the RMP field on impurity transport, based on high-performance extreme ultraviolet impurity spectroscopic diagnostics, the effect of the n = 1 (n is the toroidal mode number) RMP field on the behavior of intrinsic impurity ions at the plasma edge, e.g. He+, Li2+, C2+–C5+, O5+, Fe8+, Fe15+, Fe17+, Fe22+, Cu17+, Mo12+, Mo13+ and W27+, is analyzed for the first time in L-mode discharges. Based on the evaluation of the location of these impurity ions, it is found that with the increase in RMP current (I
RMP), an impurity screening layer inside the last closed flux surface is formed, e.g. at ρ = 0.74–0.96, which is also the region that the RMP field affects. Outside this screening layer, the impurity ion flux of He+, Li2+, C2+, C3+, O5+, Fe8+, Mo12+ and Mo13+ ions increases gradually, while inside this screening layer, the impurity ion flux of C4+, C5+, Cu17+, W27+, Fe15+, Fe17+ and Fe22+ ions decreases gradually. When I
RMP is higher than a threshold value, RMP field penetration occurs, accompanied with m/n = 2/1 mode locking, and the position of this screening layer moves to the plasma core region, i.e. ρ = 0.66–0.76, close to the q = 2 surface, and the opposite behavior of the impurity ion flux at two sides of the screening layer is strengthened dramatically. As a result, significant decontamination effects in the plasma core region, indicated by the factor of ((Γ
Imp
Z+)w/o–(Γ
Imp
Z+))/(Γ
Imp
Z+)w/o (where (Γ
Imp
Z+)/(Γ
Imp
Z+)w/o denotes the impurity ion flux ratio with and without RMP), is observed, i.e. 30%–60% for heavy impurity (Fe, Cu, Mo, W), and ∼27% for light impurity of C. In addition, the analysis of the decontamination effects of C and Fe impurities under four different RMP phase configurations shows that it may be related to the strength of the response of the plasma to RMP. These results enhance the understanding of impurity accumulation suppression by the n = 1 RMP field and demonstrate a candidate approach using RMP coils for W control in magnetic confinement devices.
High-beta disruption prediction study on HL-2A with instance-based transfer learning
Authors: Zhong Y. , Zheng W. , Chen Z.Y. , Yan W. , Xia F. , Yu L.M. , Xue F.M. , Shen C.S. , Ai X.K. , Yang Z.Y. , Yu Y.L. , Nie Z.S. , Ding Y.H. , Liang Y.F. , Chen Z.P. ,   J-TEXT Team
Published: June 2024

Abstract
Unmitigated disruptions pose a much more serious threat when large-scale tokamaks are operating in the high performance regime. Machine learning based disruption predictors can exhibit impressive performance. However, their effectiveness is based on a substantial amount of training data. In future reactors, obtaining a substantial amount of disruption data in high performance regimes without risking damage to the machine is highly improbable. Using machine learning to develop disruption predictors on data from the low performance regime and transfer them to the high performance regime is an effective solution for a large reactor-sized tokamak like ITER and beyond. In this study, a number of models are trained using different subsets of data from the HL-2A tokamak experiment. A SHapley Additive exPlanations (SHAP) analysis is executed on the models, revealing that there are different, even contradicting, patterns between different performance regimes. Thus, simply mixing data among different performance regimes will not yield optimal results. Based on this analysis, we propose an instance-based transfer learning technique which trains the model using a dataset generated with an optimized strategy. The strategy involves instance and feature selection based on the physics behind differences in high- and low-performance discharges, as revealed by SHAP model analysis. The TrAdaBoost technique significantly improved the model performance from 0.78 BA (balanced accuracy) to 0.86 BA with a few high-performance operation data.
Inequalities in the production and use of cement and concrete, and their consequences for decarbonisation and sustainable development
Authors: Marsh Alastair T M , Parker Rachel , Mdee Anna L , Velenturf Anne P M , Bernal Susan A 
Published: June 2024

Abstract
Concrete is vital for constructing infrastructure and housing, and cement is the key binding material within concrete. Concrete is an enabler of development, as concrete structures are key to delivering societal services in many sectors. Much recent research on cement and concrete has focussed on technical solutions to decarbonisation; however, there is a knowledge gap around how cement and concrete intersect with other facets of sustainable development. This study explores the intersection of cement and concrete with inequalities, both through their production as commodities and through their use in built assets. An exploratory analysis of this issue was carried out, comprising an evaluation of industry associations’ conceptions of sustainable development and inequalities, an analysis of underlying power dynamics for several inequality issues using Lukes’ three dimensional framework of power, and a reflection on how certain inequalities may pose risks to achieving decarbonisation and sustainable development aims. Our study shows that industry associations’ narratives around sustainable development generally lack a detailed vision for addressing inequalities, in comparison to their focus on decarbonisation. We find that inequalities are a systemic issue for cement and concrete, spanning intra- and inter-national scales, and all three dimensions of power. These findings highlight that several inequalities are consequential from structural, underlying inequalities, whilst other inequalities are specific to the sectors themselves. The cement and concrete sectors are recommended to develop their conception of inequalities in relation to sustainable development: this can help reduce inequalities within their own workforces more effectively, and also reduce the risks of missing their decarbonisation targets. For large, complex socio-technical systems, such as cement and concrete, it is vital for consideration of inequalities to inform strategic planning with regards to decarbonisation and sustainable development.
High traffic roads and adverse birth outcomes: comparing births upwind and downwind of the same road
Authors: Larkin Andrew , Willis Mary D , Harris Lena , Ritz Beate , Hill Elaine L , Hystad Perry 
Published: June 2024

Abstract
Traffic-related air pollution is a major concern for perinatal health. Determining causal associations, however, is difficult because high-traffic areas tend to correspond with lower socioeconomic neighborhoods and other environmental exposures. To overcome confounding, we compared pregnant individuals living downwind and upwind of the same high-traffic road. We leveraged vital statistics data for Texas from 2007 to 2016 (n = 3 570 272 births) and computed hourly wind estimates for residential addresses within 500 m of high-traffic roads (ie, annual average daily traffic &gt;25 000 vehicles) (10.9% of births). We matched pregnant individuals predominantly upwind with pregnant neighbors downwind of the same road segment (n = 37 631 pairs). Living downwind was associated with a decrease of 11.6 g (95% CI, -18.01 to -5.21) in term birth weight. No associations were observed with low term birth weight, preterm birth, or very preterm birth. In distance-stratified models, living downwind within 50 m was associated with a decrease of 36.3 g (95% CI, -67.74 to -4.93) in term birth weight and living 51-100 m downwind was associated with an odds ratio of 3.68 (95% CI, 1.71-7.90) for very preterm birth. These results suggest traffic air pollution is associated with adverse birth outcomes, with steep distance decay gradients around major roads.
This article is part of a Special Collection on Environmental Epidemiology.
Learning optimal dynamic treatment regimes from longitudinal data
Authors: Williams Nicholas T , Hoffman Katherine L , Díaz Iván , Rudolph Kara E 
Published: June 2024

Abstract
Investigators often report estimates of the average treatment effect (ATE). While the ATE summarizes the effect of a treatment on average, it does not provide any information about the effect of treatment within any individual. A treatment strategy that uses an individual’s information to tailor treatment to maximize benefit is known as an optimal dynamic treatment rule (ODTR). Treatment, however, is typically not limited to a single point in time; consequently, learning an optimal rule for a time-varying treatment may involve not just learning the extent to which the comparative treatments’ benefits vary across the characteristics of individuals, but also learning the extent to which the comparative treatments’ benefits vary as relevant circumstances evolve within an individual. The goal of this paper is to provide a tutorial for estimating ODTR from longitudinal observational and clinical trial data for applied researchers. We describe an approach that uses a doubly robust unbiased transformation of the conditional ATE. We then learn a time-varying ODTR for when to increase buprenorphine-naloxone dose to minimize a return to regular opioid use among patients with opioid use disorder. Our analysis highlights the utility of ODTRs in the context of sequential decision-making: The learned ODTR outperforms a clinically defined strategy.
This article is part of a Special Collection on Pharmacoepidemiology.