bluuebunny/crossref_metadata_2025_split huggingface dataset:
Let’s talk about sex in high school
Authors: Sánchez Ruiz Raquel 
Published: October 2020

Abstract
Although sex has always been a controversial
topic, in the last years the taboo surrounding sex and sexuality has
progressively relaxed, which has led to the appearance of TV series
in which sex plays a fundamental role. A good case in point is
Sex Education, a comedy-drama series about
teenagers’ sexual issues in the setting of sex-therapy sessions.
This chapter’s main aim is to analyse how high school students talk
about and conceptualise sexual topics in eight episodes of the
series, considered here an instance of telecinematic discourse. The
results reveal that the X-phemistic (i.e., euphemistic and
dysphemistic) units teenagers use to talk about sex provide good
evidence of their beliefs and value judgements related to
sexuality.
Phonological development in Spanish immersion
Authors: Menke Mandy R. 
Published: October 2020

AbstractStudies of lexical and syntactic development in immersion programs are numerous, yet phonological development has received much less attention. This study compares the pronunciation of English home language students in one-way and two-way Spanish immersion programs across three sound classes: voiceless stops, rhotics, and vowels. Learner productions were analyzed acoustically and compared to those of Spanish-English bilingual peers. Findings suggest that the two-way immersion context may facilitate more nativelike articulation. Amount of exposure to native speaker input, emerging adolescent identity, and decreases in instructional use of the minority language are explored as contributing factors to the greater outcomes of two-way students.
Covariance of the extended holonomy
Authors: Gambini Rodolfo , Pullin Jorge , Skirzewski Aureliano 
Published: October 2020

AbstractIt has been pointed out that the holonomy of generic extended loops is not gauge covariant. We show how to define a family of extended loops for which previous criticism does not apply. We also give sufficient conditions that extended loops must satisfy in order to yield covariant holonomies. This makes a quantum representation for Yang–Mills theories and gravity based on extended loops viable.
Tikhonov-like methods with inexact minimization for solving linear ill-posed problems
Authors: Margotti Fábio , Rabelo Joel 
Published: October 2020

Abstract
In this article we propose and study the properties of three distinct algorithms for obtaining stable approximate solutions for systems of ill-posed equations, modeled by linear operators acting between Hilbert spaces. Based on Tikhonov-like methods with uniformly convex penalty terms, we develop new versions with inexact minimization of both one step and iterated-Tikhonov methods. For the case of one step methods, we propose two distinct algorithms, one based in a priori and one based in a posteriori choice of the regularization parameter. Convergence and stability properties are provided, as well as optimal convergence rates (under appropriate source conditions). The third algorithm is based in a variant of the iterated-Tikhonov method with a posteriori choice of the sequence of penalization parameters. For this algorithm, we prove stability for noisy data and the regularization property.
Organic electronics Axon-Hillock neuromorphic circuit: towards biologically compatible, and physically flexible, integrate-and-fire spiking neural networks
Authors: Mirshojaeian Hosseini Mohammad Javad , Donati Elisa , Yokota Tomoyuki , Lee Sunghoon , Indiveri Giacomo , Someya Takao , Nawrocki Robert A 
Published: October 2020

Abstract
Spiking neural networks (SNNs) have emerged as a promising computational paradigm to emulate the features of natural neural tissue physiology. While hardware implementations of SNNs are being conceived to emulate biological systems, they typically rely on hard and rigid silicon electronics that are not bio-compatible. In the physical, or materials realm, organic electronics offer mechanical flexibility and bio-compatibility, allowing for the construction of neural processing systems that can be directly interfaced to biological networks. This study introduces an organic electronics implementation of an Integrate-and-Fire spiking neuron based on the Axon-Hillock CMOS circuit. The circuit employs organic p-type and n-type field effective transistors and reproduces the behavior of the CMOS neuromorphic counterpart. We demonstrate its operating characteristics measuring its spike rate output as a function of its input current. We show how it properly integrates input currents and demonstrate its computing abilities in a basic current summing experiment. The static and dynamic power dissipation is calculated to be less than 0.4 and 40 µW, respectively. This is the first demonstration of the spiking Axon-Hillock neuromorphic circuit using organic materials.
Topological insulator in a hexagonal plate with droplet holes
Authors: Zhang Kai , Hong Fang , Luo Jie , Deng Zichen 
Published: October 2020

Abstract
In this study, we introduce a tunable topological insulator (TI) system consisting of a hexagonal aluminum plate with rotatable droplet-shaped holes to produce topologically protected edge waves (TPEWs) along a topological interface. By rotating the round plate in the unit cells to break the unit cells’ mirror symmetry while preserving C3 symmetry, a new band gap is produced from the dispersion relations’ Dirac point. A topological protection state is generated at the interface due to the valley Hall effect. We also simulate different TPEWs along disparate interface routes and further prove their robustness, which means that they are immune to the vast majority of backscattering along interfaces. We also demonstrate that TPEWs at specific frequencies can be transported to different locations in hexagonal TIs, which is an innovative technique for precise control of acoustic guidance. This study provides a new method to modulate guide waves and energy accumulation of different frequency waves in topological systems.
3D computational study of arc splitting during power interruption: the influence of metal vapor enhanced radiation on arc dynamics
Authors: Huo Jindong , Wang Yifei , Cao Yang 
Published: October 2020

Abstract
Arc splitting is one of the most important processes in accomplishing a power interruption by multiplying the number of voltage drops. During arc-plate interaction, the arc roots erode and vaporize the metals which significantly alters the gas composition and plasma properties, such as the radiation absorption coefficient. In this work, we perform a 3D computational study of arc splitting in a circuit breaker. In order for the study to be systematic, the metal vaporization, species transport, and radiative heat transfer are integrated into the magnetohydrodynamics modeling with some special considerations. Firstly, the simulation considers the ferromagnetic effect of steel plates. Secondly, the metal-vapor-enhanced radiation is numerically implemented by the discrete ordinate method with consideration given to the banded radiation spectrum. Thirdly, the simulation model incorporates a near-electrode layer to implement the voltage drop and imposes additional heat flux on the arc spots. The simulation results show that the metal vaporization not only influences the arc dynamics (via Stefan flow) but also enhances the local radiation intensity. Besides, due to the ferromagnetic effect, the magnetic field increases dramatically during arc splitting. However, the self-induced magnetic force has quite a different influence on the motion of sub-arcs, which prevents even and concurrent arc splitting. This simulation reveals that the magnetic-field-induced uneven splitting can be compensated by the enhanced pressure wave or externally applied transversal magnetic field. This study is expected to explore more applications in simulating arc interruption and improve the design of highly-efficient circuit breakers.
Supreme enhancement of ferromagnetism in a spontaneous-symmetry-broken 2D nanomagnet
Authors: Kar S , Nair A K , Ray S J 
Published: October 2020

Abstract
The ability to tune and control the magnetic phases of two-dimensional (2D) nanomagnets at room temperature is indispensable for the development of future spintronics and low-dimensional spin circuits. In this work, a first-principles-based investigation combined with a Monte Carlo simulation based on a 2D Ising model is used to investigate the electronic and magnetic behaviour of a recently discovered 2D material, Cr2Ge2Se6 over a large range of strain and electric field strength. This material offers ferromagnetic

→

antiferromagnetic and semiconductor

→

metallic phase transitions in different regimes. In the presence of strain, a colossal enhancement of the critical temperature (T

c
) is observed, from 149 K to 885 K. The application of an electric field allows a further enhancement of the T

c
to a value of 919 K, offering a supreme enhancement (~517%), compared to its natural condition. The origin of this behavior can be traced to a super-exchange interaction between the Cr and Se atoms and the intrinsic magnetic anisotropy of Cr2Ge2Se6. The presence of external stimuli engenders spontaneous symmetry breaking with an enhanced magnetic moment (~4.36

μ

B

/Cr atom), a significant intrinsic spin polarisation (~100%) in a half-metallic regime, and a very high critical temperature. The insights of the current investigation could be useful for future developments in multi-stimuli-assisted room-temperature ferromagnetism and electronic phase control, which are of great significance for future magneto-electronic applications.
Thermo-mechanical modeling and characterization of three-phase shape memory alloy hybrid composites
Authors: Yu Haifan , Lu Linjun , Qiao Pizhong 
Published: October 2020

Abstract
The thermo-mechanical properties of shape memory alloy hybrid composites (SMAHCs) are characterized, and their three-phase constitutive relationship in the form of a lamina embedded with shape memory alloy (SMA) wires is established by micromechanics. Considering large beam deflection, a theoretical bending model of SMAHC beams with different fiber volume fractions and arbitrary ply schemes is proposed. The Runge–Kutta method is employed to solve the nonlinear ordinary differential equations, and the quantitative relations of curvature, rotation and deflection under thermal load are obtained from the model by directly using the original three-phase material parameters without the need of the experimental measurement in single layer. The SMAHC beams with different fiber orientation, number of layers, and volume fraction of SMA are fabricated, and their thermo-mechanical behavior is experimentally evaluated. Good agreements between the theoretical predictions and experimental results demonstrate that the proposed model is capable of predicting the thermo-mechanical behavior of three-phase SMAHC beams. The generic model developed can be used as an analytical tool in design analysis and optimization of SMAHC structures for effective shape, tracking, and vibration control.
Synergistic effect of ion chelating agent and inorganic compound on pore structure, mechanical and self-healing performance of cement-based materials
Authors: Gu Shunjie , Wang Ruiyang , He Peng , Du Wei , Yu Jianying 
Published: October 2020

Abstract
Ion chelating agent can effectively improve the self-healing of concrete. In order to further enhance the self-healing ability of cement-based materials, ion chelating agent and inorganic compounds (sodium silicate and sodium bicarbonate) were used together in this paper. Pore size distribution, mechanical and self-healing performance of the mortars with ion chelating agent and inorganic compounds were investigated. The results showed that harmful pores (pore diameter above 0.1 μm) of the mortar was reduced and mechanical properties was increased by adding ion chelating agent and inorganic compounds, especially mortar mixed with 0.50% ion chelating agent and 0.25% sodium silicate had the least harmful pores and the highest compressive strength and flexural strength. Moreover, the self-healing properties of mortars were significantly improved by combination of ion chelating agent and inorganic compound. Especially for mortar mixed with 0.5% ion chelating agent and 0.5% sodium silicate, the relative water permeability coefficient decreased to 0 after curing for 28 d, and the cracks with width of 0.31 mm and 0.46 mm could be completely closed after curing for 3 d and 28 d respectively. SEM observation showed that the calcium carbonate, ettringite and calcium carbonate were covered by CSH gel in the cracks and interior of the mortar mixed with ion chelating agent and sodium silicate, which proved that the ion chelating agent and sodium silicate had synergistic effect on the self-healing properties of cement-based materials.
X-ray standing wave studies of molecular adsorption: why coherent fractions matter
Authors: Woodruff D P , Duncan D A 
Published: October 2020

Abstract
The normal incidence x-ray standing wave (NIXSW) technique is the primary source of quantitative experimental information on the adsorption height of many near-planar molecules on metal surfaces, of relevance to organic electronics. The technique yields two structural parameters, the coherent position and the coherent fraction. For high values of the coherent fraction the coherent position can be related directly to the adsorption height, but because the coherent fraction is effectively an order parameter, low values of this parameter are often attributed to partial disorder. It is certainly true that in depositing these large molecules on a surface it is very challenging to produce a perfectly ordered surface. However, is the type of disorder that is likely to occur able to account for no other effect on measured NIXSW data than a lowering of the coherent fraction? Here we show, by considering a wide range of possible types of ‘disorder’, that in almost all such situations it is improbable that the coherent positions associated with very low coherent fractions actually provide a reliable measure of the adsorption height of the ordered component, as is often assumed to be the case. As such, presentations of NIXSW data that only consider coherent position values are likely to be extremely misleading, and provide an unreliable benchmark for detailed understanding of these interfaces.
The Tsinghua University-Ma Huateng Telescopes for Survey: Overview and Performance of the System
Authors: Zhang Ji-Cheng , Wang Xiao-Feng , Mo Jun , Xi Gao-Bo , Lin Jie , Jiang Xiao-Jun , Zhang Xiao-Ming , Li Wen-Xiong , Yan Sheng-Yu , Chen Zhi-Hao , Hu Lei , Li Xue , Lin Wei-Li , Lin Han , Miao Cheng , Rui Li-Ming , Sai Han-Na , Xiang Dan-Feng , Zhang Xing-Han 
Published: October 2020

Abstract
Over the past decade, time-domain astronomy in optical bands has developed rapidly with the operations of some wide-field survey facilities. However, most of these surveys are conducted with only a single band, and simultaneous color information is usually unavailable for the objects monitored during the survey. Here we present introductions to the system of Tsinghua University-Ma Huateng Telescopes for Survey (TMTS), which consists of an array of four optical telescopes installed on a single equatorial mount. Such a system is designed to get multiband photometry simultaneously for stars and transients discovered during the survey. The optics of each telescope is a modified Hamilton-Newtonian system, covering the wavelengths from 400 to 900 nm, with a field of view (FoV) of about 4.5 deg2 and a plate scale of 1.″86 pixel−1 when combining with a 4K × 4K QHY4040 CMOS detector. The TMTS system can have a FoV of about 9 deg2 when monitoring the sky with two bands (i.e., SDSS g and r filters) at the same time, and a maximum FoV of ∼18 deg2 when four telescopes monitor different sky areas in monochromatic filter mode. For an exposure time of 60 s, the average 3σ detection limit of the TMTS system can reach at ∼19.4 mag in Luminous filter and at ∼18.7 mag in SDSS r filter. The preliminary discovery obtained during the first few months’ survey is briefly discussed. As this telescope array is located at the Xinglong Observatory of NAOC, it can have an excellent synergy with the spectroscopic survey by the LAMOST (with a FoV of about 20 deg2) at the same site, which will benefit the studies of stellar and binary physics besides the transient sciences.
Observational signatures of close binaries of supermassive black holes in active galactic nuclei
Authors: Wang Jian-Min , Li Yan-Rong 
Published: October 2020

Abstract
Inspired by the General Relativity for many decades, experimental physicists and astronomers have a solid dream to detect gravitational waves (GWs) from mergers of black holes, which came true until the excellent performance of the Laser Interferometer Gravitational-Wave Observatory (LIGO) at hundreds Hz. Nano-Hz GWs are expected to be radiated by close-binaries of supermassive black holes (CB-SMBHs; defined as those with separations less than ∼0.1 pc) formed during galaxy mergers and detected through the Pulsar Timing Array (PTA) technique. As of the writing, there remains no nano-Hz GWs detection. Searching for CB-SMBHs is also observationally elusive though there exist a number of possible candidates. In this review, we focus on observational signatures of CB-SMBHs from theoretic expectations, simulations and observations. These signatures appear in energy distributions of multiwavelength continuum, long term variations of continuum, jet morphology, reverberation delay maps and spectroastrometry of broad emission lines, AGN type transitions between type-1 and type-2 (changing-look), and gaseous dynamics of circumbinary disks, etc. Unlike hundred-Hz GWs from stellar mass black hole binaries, the waveform chirping of nano-Hz GWs is too slow to detect in a reasonable human timescale. We have to resort to electromagnetic observations to measure orbital parameters of CB-SMBHs to test nano-Hz GW properties. Reverberation mapping is a powerful tool for probing kinematics and geometry of ionized gas in the gravitational well of SMBHs (single or binary) and therefore provides a potential way to determine orbital parameters of CB-SMBHs. In particular, a combination of reverberation mapping with spectroastrometry (realized at the Very Large Telescope Interferometer) will further reinforce this capability. The Atacama Large Millimeter/submillimeter Array (ALMA) and the forthcoming Square Kilometre Array (SKA) are suggested to reveal dynamics of circumbinary disks through molecular emission lines.
The youngest X-ray binaries
Authors: Li Xiang-Dong 
Published: October 2020

Abstract
Several X-ray binaries (XRBs) have been identified to be associated with supernova remnants (SNRs). Because of the short lifetimes of SNRs, this leaves them to be the youngest known XRBs. This small group of binaries provides valuable information on the formation of compact stars under the framework of massive binary evolution. In this paper we review the observational characteristics of these youngest XRBs and discuss their possible implications on the initial conditions of compact stars and their interaction with the companion stars.
Contact binaries at different evolutionary stages
Authors: Qian Sheng-Bang , Zhu Li-Ying , Liu Liang , Zhang Xu-Dong , Shi Xiang-Dong , He Jia-Jia , Zhang Jia 
Published: October 2020

Abstract
Contact binaries consist of two strongly interacting component stars where they are filling their critical Roche lobes and sharing a common envelope. Most of them are main-sequence stars, but some of them are post main-sequence systems. They are good astrophysical laboratories for studying several problems such as the merging of binary stars, evolution of the common envelope, the origin of luminous red nova outbursts and the formation of rapidly rotating single stars with possible planetary systems. A large number of contact binary candidates were detected by several photometric surveys around the world and many of them were observed by the LAMOST spectroscopic survey. Based on follow-up observations, the evolutionary states and geometrical structures of some systems were understood well. In this review, we will introduce and catalog new stellar atmospheric parameters (i.e., the effective temperature (T
eff), the gravitational acceleration (log(g)), metallicity ([Fe/H]) and radial velocity (Vr
)) for 9149 EW-type contact binaries that were obtained based on low- and medium-resolution spectroscopic surveys of LAMOST. Then we will focus on several groups of contact binary stars, i.e., marginal contact binary systems, deep and low-mass ratio contact binary stars, binary systems below the short-period limit of contact binaries and evolved contact binaries. Marginal contact binaries are at the beginning of the contact stage, while deep and low-mass ratio contact binary stars are at the final evolutionary stage of tidally locked binaries. Several statistical relations including the period-temperature relation are determined well by applying LAMOST data and their formation and evolutionary states are reviewed. The period-color relation of M-type binaries reveals that there are contact binaries below the short-period limit. Searching for and investigating contact binaries near and below this limit will help us to understand the formation of contact binary systems and a new prediction for the short-period limit is about 0.15 d. Some evolved contact binaries were detected by the LAMOST survey where both components are sub-giants or giants. They provide a good opportunity to investigate evolution of the common envelope and are the progenitors of luminous red novae like V1309 Sco.
Magnetic flux ropes in the solar corona: structure and evolution toward eruption
Authors: Liu Rui 
Published: October 2020

Abstract
Magnetic flux ropes are characterized by coherently twisted magnetic field lines, which are ubiquitous in magnetized plasmas. As the core structure of various eruptive phenomena in the solar atmosphere, flux ropes hold the key to understanding the physical mechanisms of solar eruptions, which impact the heliosphere and planetary atmospheres. The strongést disturbances in the Earth’s space environments are often associated with large-scale flux ropes from the Sun colliding with the Earth’s magnetosphere, leading to adverse, sometimes catastrophic, space-weather effects. However, it remains elusive as to how a flux rope forms and evolves toward eruption, and how it is structured and embedded in the ambient field. The present paper addresses these important questions by reviewing current understandings of coronal flux ropes from an observer’s perspective, with an emphasis on their structures and nascent evolution toward solar eruptions, as achieved by combining observations of both remote sensing and in-situ detection with modeling and simulation. This paper highlights an initiation mechanism for coronal mass ejections (CMEs) in which plasmoids in current sheets coalesce into a ‘seed’ flux rope whose subsequent evolution into a CME is consistent with the standard model, thereby bridging the gap between microscale and macroscale dynamics.