bluuebunny/crossref_metadata_2025 huggingface dataset:
Uniform atmospheric pressure plasmas in a 7 mm air gap
Authors: Qi Fei , Li Yiyang , Zhou Rusen , Zhou Renwu , Wan Jianjian , Xian Yubin , Cullen Patrick J , Lu Xinpei , Ostrikov Kostya (Ken)
Published: November 2019

Homogeneous penetration of atmospheric pressure uniform air plasma (APUAP) into thin gaps is highly warranted for multipurpose processing of materials. Here, we report APUAP generation in a 7 mm discharge gap with ambient air as the working gas, well beyond the presently maximum achievable 4 mm. Driven by a short pulse high voltage power, a 7 mm wide and 60 mm long uniform air plasma sheet is generated. The discharge is robust and the uniformity is not affected by the complex and variable components of ambient air, as is the case for most plasma discharges in air. Ultrafast photography shows that, different from previous reports, the discharge initiates in the whole air gap simultaneously and brightens quickly with the fast rise of the pulsed voltage. The generation of uniform plasma is mainly attributed to the high density of seed electrons and the reduced number density of molecules in air. Moreover, the achievable gas temperature of up to 1300 K indicates that this type of plasma is suitable for processing of a broad range of materials.
Chromatic matching in a plasma undulator
Authors: Djordjević B. Z. , Benedetti C. , Schroeder C. B. , Esarey E.
Published: November 2019

The principle of chromatic matching, i.e., using two laser modes of different geometric mode numbers and different colors so that they copropagate at the same group velocity, is proposed in order to realize the plasma undulator concept. Chromatic matching allows one to overcome group velocity slippage, whereby lower-order modes outrun higher-order ones, allowing for extended interaction lengths. The dephasing limit can be mitigated by using a special tapering of the plasma channel such that the electron bunch propagates in phase with the laser mode in addition to maintaining a constant undulator frequency. Furthermore, controlled dephasing is proposed as a means to induce chirp in the generated X-ray spectrum.
The complex behavior of the “simplest” liquid: Breakdown of density scaling in tetramethyl tetraphenyl trisiloxane
Authors: Ransom T. C. , Casalini R. , Fragiadakis D. , Roland C. M.
Published: November 2019

Dielectric relaxation measurements, in combination with density determinations, on tetramethyl tetraphenyl trisiloxane (DC704) over an unusually broad range of temperatures and pressures revealed a state-point dependency in its density scaling exponent. This is the first unambiguous experimental demonstration of a breakdown of density scaling in a nonassociated glass-forming material, and unanticipated for DC704, among the “simplest” of liquids, having a constant breadth of the relaxation dispersion and a Prigogine-Defay ratio near unity characteristic of approximate single-parameter systems. We speculate that the anomalous behavior has origins in the large value of its scaling exponent and relative flexibility of the chemical structure.
Engineering nonlinear response of superconducting niobium microstrip resonators via aluminum cladding
Authors: Kwon Sangil , Tang Yong-Chao , Mohebbi Hamid R. , Benningshof Olaf W. B. , Cory David G. , Miao Guo-Xing
Published: November 2019

In this work, we find that Al cladding on Nb microstrip resonators is an efficient way to suppress nonlinear responses induced by local Joule heating, resulting in improved microwave power handling capability. This improvement is likely due to the proximity effect between the Al and the Nb layers. The proximity effect is found to be controllable by tuning the thickness of the Al layer. We show that improving the film quality is also helpful as it enhances the microwave critical current density, but it cannot eliminate the local heating.
An ab initio study of reversible dihydrogen adsorption in metal decorated γ-graphyne
Authors: Sathe Rohit Y. , Kumar Sandeep , Dhilip Kumar T. J.
Published: November 2019

We present the detailed comparative study of dihydrogen adsorption in Li, Mg, Ca, and Sc decorated γ-graphyne (Gγ) performed with density functional theory calculations. Hydrogen molecules are sequentially loaded onto metal decorated Gγ. Maximum hydrogen weight percentage for Li, Mg, Ca, and Sc decorated Gγ is found to be 8.69, 7.73, 8.10, and 6.83, respectively, with maximum 8 H2 on Li, Mg, and Sc while 10 on Ca decorated Gγ. All hydrogen molecules are physisorbed over all the complexes except that the first one on each Sc of Gγ-2Sc is chemisorbed. Orbital hybridization involved in Dewar coordination of metal decoration and the Kubas mechanism of hydrogen adsorption has been explained with the partial density of states. Lower values of adsorption and desorption energies in these complexes indicate the reversibility of adsorption. These complexes obey high hardness and low electrophilicity principles and contain no imaginary frequencies which specify their stability. In Born-Oppenheimer molecular dynamics, reversibility of adsorption is proven at various temperatures. Based on the comparative studies of hydrogen weight percentage, energetics, stability, and reversibility, Gγ-2Ca is proven to be a better hydrogen storage candidate. This comprehensive study confirms the potential of metal decorated γ-graphyne as a suitable hydrogen storage material.
Piezoelectric polyvinylidene fluoride-based epoxy composites produced by combined uniaxial compression and poling
Authors: Bezaitis Konstantinos , Papathanassiou Anthony N. , Sakellis Elias
Published: November 2019

We present a simple, efficient method, which combines uniaxial compression and subsequent poling, to produce piezoelectric polyvinylidene fluoride-based epoxy composites. The values of the piezoelectric factors obtained are slightly higher than those of neat piezoelectric polyvinylidene fluoride. The composites respond rapidly and reach a saturation voltage output, to the application of mechanical stimulus quickly. The composites are promising for the creation of “bulk” piezoelectric devices, different from the usual stretched films, exploiting the physico-chemical a of the epoxy matrix. The piezoelectric factor d31 vs the mechanical stimulus for the specimens studied scale according to a double logarithmic representation.
A hybrid approach to extending selected configuration interaction and full configuration interaction quantum Monte Carlo
Authors: Blunt Nick S.
Published: November 2019

We present an approach to combining selected configuration interaction (SCI) and initiator full configuration interaction quantum Monte Carlo (i-FCIQMC). In the current i-FCIQMC scheme, the space of initiators is chosen dynamically by a population threshold. Here, we instead choose initiators as the selected space (V) from a prior SCI calculation, allowing substantially larger initiator spaces for a given walker population. While SCI+PT2 adds a perturbative correction in the first-order interacting space beyond V, the approach presented here allows a variational calculation in the same space and a perturbative correction in the second-order interacting space. The use of a fixed initiator space reintroduces population plateaus into FCIQMC, but it is shown that the plateau height is typically only a small multiple of the size of V. Thus, for a comparable fundamental memory cost to SCI+PT2, a substantially larger space can be sampled. The resulting method can be seen as a complementary approach to SCI+PT2, which is more accurate but slower for a common selected/initiator space. More generally, our results show that approaches exist to significantly improve initiator energies in i-FCIQMC while still ameliorating the fermion sign problem relative to the original FCIQMC method.
Band alignment and charge transfer in CsPbBr3–CdSe nanoplatelet hybrids coupled by molecular linkers
Authors: Dey Swayandipta , Cohen Hagai , Pinkas Iddo , Lin Hong , Kazes Miri , Oron Dan
Published: November 2019

Formation of a p-n junction-like with a large built-in field is demonstrated at the nanoscale, using two types of semiconducting nanoparticles, CsPbBr3 nanocrystals and CdSe nanoplatelets, capped with molecular linkers. By exploiting chemical recognition of the capping molecules, the two types of nanoparticles are brought into mutual contact, thus initiating spontaneous charge transfer and the formation of a strong junction field. Depending on the choice of capping molecules, the magnitude of the latter field is shown to vary in a broad range, corresponding to an interface potential step as large as ∼1 eV. The band diagram of the system as well as the emergence of photoinduced charge transfer processes across the interface is studied here by means of optical and photoelectron based spectroscopies. Our results propose an interesting template for generating and harnessing internal built-in fields in heterogeneous nanocrystal solids.
Review of transport processes and particle self-assembly in acoustically levitated nanofluid droplets
Authors: Pandey Khushboo , Prabhakaran Deepu , Basu Saptarshi
Published: November 2019

Acoustic levitation has been the cornerstone of many interesting studies across multiple application domains ranging from biomedical engineering to spray drying. In the sphere of colloidal or nanofluid droplets, acoustic levitation allows researchers to probe deep into the physical mechanisms concerning stability, heat and mass transfer processes, and subsequent particle self-assembly. It also offers a plethora of opportunities to custom engineer the transport mechanisms, thereby enabling unique morphological features of the dried precipitate. The high degree of spatial control in a levitator and ease of experimental diagnostics ensure one to study any such transport process in great detail. In this review, we have systematically elucidated three important paradigms in acoustic levitation of nanofluid droplets. First, we have provided a detailed understanding of the fluid mechanics of the process by delving into the pressure and velocity fields the droplet encounters. We have provided descriptions about the key nondimensional number responsible for successful levitation of the droplet. Second, we have studied the transport processes in nanofluid droplets and investigated the important transport mechanisms that are affected by flow and the acoustic field of the levitator. In particular, we look into the heat and mass transfer limitation for particle laden droplets. Third, we have analyzed the particle self-assembly and formation of nanoporous viscoelastic shell. Subsequently, we provided detailed insights into the morphological transitions of the shell through buckling and cavity ingression. We also showcase how the morphology of the shell can be controlled using differential heating and doping. Finally, we conclude by showcasing some unique application context-like photonic crystal behavior that can emerge from unique particle assembly in acoustic levitation.
The effect of self-interaction error on electrostatic dipoles calculated using density functional theory
Authors: Johnson Alexander I. , Withanage Kushantha P. K. , Sharkas Kamal , Yamamoto Yoh , Baruah Tunna , Zope Rajendra R. , Peralta Juan E. , Jackson Koblar A.
Published: November 2019

Spurious electron self-interaction in density functional approximations (DFAs) can lead to inaccurate predictions of charge transfer in heteronuclear molecules that manifest as errors in calculated electrostatic dipoles. Here, we show the magnitude of these errors on dipoles computed for a diverse set of 47 molecules taken from the recent benchmark study of Hait and Head-Gordon [J. Chem. Theory Comput. 14, 1969 (2018)]. We compare the results of Perdew-Wang local spin density approximation (PW92), Perdew-Burke-Ernzerhof (PBE) generalized gradient approximation (GGA), and strongly constrained and appropriately normed (SCAN) meta-GGA dipole calculations, along with those of their respective self-interaction-corrected (SIC) counterparts, to reference values from accurate wave function-based methods. The SIC calculations were carried out using the Fermi-Löwdin orbital (FLO-SIC) approach. We find that correcting for self-interaction generally increases the degree of charge transfer, thereby increasing the size of calculated dipole moments. The FLO-SIC-PW92 and FLO-SIC-PBE dipoles are in better agreement with reference values than their uncorrected DFA counterparts, particularly for strongly ionic molecules where significant improvement is seen. Applying FLO-SIC to SCAN does not improve dipole values overall. We also show that removing self-interaction improves the description of the dipole for stretched-bond geometries and recovers the physically correct separated atom limit of zero dipole. Finally, we find that the best agreement between the FLO-SIC-DFA and reference dipoles occurs when the molecular geometries are optimized using the FLO-SIC-DFA.
Thermal expansion in insulating solids from first principles
Authors: Ritz Ethan T. , Li Sabrina J. , Benedek Nicole A.
Published: November 2019

In this Tutorial, we describe the use of the quasiharmonic approximation and first-principles density functional theory (DFT) to calculate and analyze the thermal expansion of insulating solids. We discuss the theory underlying the quasiharmonic approximation and demonstrate its practical use within two common frameworks for calculating thermal expansion: the Helmholtz free energy framework and the Grüneisen theory. Using the example of silicon, we provide a guide for predicting how the lattice parameter changes as a function of temperature using DFT, including the calculation of phonon modes and phonon density of states, elastic constants, and specific heat. We also describe the calculation and interpretation of Grüneisen parameters, as well as how they relate to coefficients of thermal expansion. The limitations of the quasiharmonic approximation are briefly touched on, as well as the comparison of theoretical results with experimental data. Finally, we use the example of ferroelectric PbTiO3 to illustrate how the methods used can be adapted to study anisotropic systems.
A perspective on the bright future of metal halide perovskites for X-ray detection
Authors: Sytnyk Mykhailo , Deumel Sarah , Tedde Sandro Francesco , Matt Gebhard J. , Heiss Wolfgang
Published: November 2019

Metal halide perovskites (MHPs) changed the world of solution processed semiconductors, previously dominated by organic semiconductors, toward predominantly inorganic materials with a relatively high electron/hole mobility. A series of devices benefit from their optoelectronic properties, including X-ray detectors. After the introduction of MHP X-ray detectors in 2013, they have achieved significant improvements in the form of single crystals, polycrystalline materials, and pixelated imaging devices. In addition, MHPs in the form of colloidal nanocrystals act as excellent scintillators. We see the bright future of MHPs in energy resolved X-ray detection, either achieved in the single counting mode, or in nanocrystal multilayer stacked devices, acting as a combination of selective X-ray filters and scintillators.
Observation of transferred-electron oscillations in diamond
Authors: Suntornwipat N. , Majdi S. , Gabrysch M. , Friel I. , Isberg J.
Published: November 2019

The transferred-electron oscillator (TEO), or Gunn oscillator, is a device used in microwave applications, which utilizes the negative differential mobility (NDM) effect to generate continuous oscillations. Recently, NDM was observed in intrinsic single-crystalline chemical vapor deposition (SC-CVD) diamond. The occurrence was explained by the electron repopulation between its different conduction band valleys. This paper presents the results of constructing a diamond TEO based on the NDM effect. A series of experiments have been performed for varying voltages, temperatures, and resonator parameters on three SC-CVD diamond samples of different thicknesses. For the temperature range of 90–300 K, we observe transferred-electron oscillations in diamond.
Ultrasmall Au clusters supported on pristine and defected CeO2: Structure and stability
Authors: Huang Si-Da , Shang Cheng , Liu Zhi-Pan
Published: November 2019

The atomistic simulation of supported metal catalysts has long been challenging due to the increased complexity of dual components. In order to determine the metal/support interface, efficient theoretical tools to map out the potential energy surface (PES) are generally required. This work represents the first attempt to apply the recently developed SSW-NN method, stochastic surface walking (SSW) global optimization based on global neural network potential (G-NN), to explore the PES of a highly controversial supported metal catalyst, Au/CeO2, system. By establishing the ternary Au–Ce–O G-NN potential based on first principles global dataset, we have searched for the global minima for a series of Au/CeO2 systems. The segregation and diffusion pathway for Au clusters on CeO2(111) are then explored by using enhanced molecular dynamics. Our results show that the ultrasmall cationic Au clusters, e.g., Au4O2, attaching to surface structural defects are the only stable structural pattern and the other clusters on different CeO2 surfaces all have a strong energy preference to grow into a bulky Au metal. Despite the thermodynamics tendency of sintering, Au clusters on CeO2 have a high kinetics barrier (>1.4 eV) in segregation and diffusion. The high thermodynamics stability of ultrasmall cationic Au clusters and the high kinetics stability for Au clusters on CeO2 are thus the origin for the high activity of Au/CeO2 catalysts in a range of low temperature catalytic reactions. We demonstrate that the global PES exploration is critical for understanding the morphology and kinetics of metal clusters on oxide support, which now can be realized via the SSW-NN method.
A dynamic wall model for large eddy simulation of turbulent flow over complex/moving boundaries based on the immersed boundary method
Authors: Ma Ming , Huang Wei-Xi , Xu Chun-Xiao
Published: November 2019

A hybrid immersed boundary/wall-model approach for large eddy simulation is developed for turbulent flows with complex/moving boundaries. The filtered Navier-Stokes equations are solved on a regular Eulerian mesh, with the no-slip condition on the wall imposed through the continuous forcing of the immersed boundary (IB) method. To implement the wall model, the thin boundary layer equation is solved on an embedded mesh refined along the wall-normal direction and a dynamic matching procedure is adopted. Near-wall subgrid-scale viscosity is further modified by taking into account the influence of IB forcing. The proposed method is tested on several numerical examples, including turbulent channel flow, turbulent flow over periodic hills, and turbulent channel flow with a traveling wavy wall. The mean velocity profile and turbulent fluctuations are reasonably well predicted in the canonical channel flow, as well as in flows with a complex/moving boundary and large flow separation.
(111)-oriented, single crystal diamond tips for nanoscale scanning probe imaging of out-of-plane magnetic fields
Authors: Rohner D. , Happacher J. , Reiser P. , Tschudin M. A. , Tallaire A. , Achard J. , Shields B. J. , Maletinsky P.
Published: November 2019

We present an implementation of all-diamond scanning probes for scanning nitrogen-vacancy (NV) magnetometry fabricated from (111)-oriented diamond material. The realized scanning probe tips on average contain single NV spins, a quarter of which have their spin quantization axis aligned parallel to the tip direction. Such tips enable single-axis vector magnetic field imaging with a nanoscale resolution, where the measurement axis is oriented normal to the scan plane. We discuss how these tips bring multiple practical advantages for NV magnetometry, in particular, regarding quantitative analysis of the resulting data. We further demonstrate the beneficial optical properties of NVs oriented along the tip direction, such as polarization-insensitive excitation, which simplifies optical setups needed for NV magnetometry. Our results will be impactful for scanning NV magnetometry in general and for applications in spintronics and the investigation of thin film magnets in particular.
Improved current-perpendicular-to-plane giant magnetoresistance outputs by heterogeneous Ag-In:Mn-Zn-O nanocomposite spacer layer prepared from Ag-In-Zn-O precursor
Authors: Nakatani T. , Sasaki T. T. , Sakuraba Y. , Hono K.
Published: November 2019

A precursor material Ag-In-Zn-O (AIZO) for the spacer layer of current-perpendicular-to-plane giant magnetoresistance devices has been developed. A pseudo-spin-valve structure with polycrystalline Co2(Mn0.6Fe0.4)Ge (CMFG) Heusler alloy ferromagnetic layers and a AIZO spacer precursor exhibited a large magnetoresistance ratio (ΔR/R) up to 54% at a resistance-area product (RA) of ∼0.075 Ω μm2 and a maximum output voltage of ∼18 mV. Cross-sectional scanning transmission electron microscopy observations revealed that the spacer layer was not uniform but had a heterogeneous Ag-In:Mn-Zn-O nanocomposite structure, which is considered to have formed by the oxidation of Mn diffused from the CMFG layers and by the reduction of In2O3 to metallic In alloyed with Ag. Due to the current-confinement effect through the fcc Ag-In metallic path (current-confined-path, CCP) with the average lateral size of ∼7 nm surrounded by a rocksalt Mn-Zn-O matrix, both RA and ΔR/R were enhanced compared to the case with the uniform AgSn alloy spacer layer. A Ag/IZO bilayer precursor also formed a similar Ag-In:Mn-Zn-O nanocomposite spacer with a lateral size of the Ag-In CCPs of ∼3 nm, and the device with the Ag/IZO precursor showed ΔR/R ∼ 30%. The difference in ΔR/R between the AIZO and Ag/IZO precursors can be explained by the matching of effective spin resistance between the CMFG ferromagnetic layers and the Ag-In CCP with different sizes. The resistance dispersion of the devices was also analyzed both experimentally and theoretically.
Formation of large negative deuterium ion beams at ELISE
Authors: Wünderlich D. , Riedl R. , Mario I. , Mimo A. , Fantz U. , Heinemann B. , Kraus W.
Published: November 2019

Negative ion sources for neutral beam injection (NBI) in fusion experiments are based on the surface production of H− or D− on cesiated low work function surfaces. In the recent years, it was demonstrated at the large RF driven ion source of the ELISE (Extraction from a Large Ion Source Experiment) test facility that the requirements for the ITER NBI systems can be fulfilled by hydrogen. This is a big step toward the first operational period of ITER, planned for up to 2035. However, for the following operational period, neutral beam systems working in deuterium are needed. Operation of negative hydrogen ion sources in deuterium is significantly more demanding than in hydrogen: the amount of coextracted electrons is much higher and their increase during pulses is much more pronounced, limiting the achievable performance. This paper presents the results of investigations aimed to improve the insight into the physics related to this isotope effect. Due to the higher atomic mass of deuterium, cesium is removed much more effectively from reservoirs at the walls, resulting in a depletion of these reservoirs and a strongly increased cesium density in the plasma. Additionally, a correlation between the fluxes of charged particles toward the inner ion source surfaces and the coextracted electrons is identified.
Designing ferroelectric/ferromagnetic composite with giant self-biased magnetoelectric effect
Authors: Deka Bipul , Lee Yong-Woo , Yoo Il-Ryeol , Gwak Do-Woo , Cho Jiung , Song Hyun-Cheol , Choi Jong-Jin , Hahn Byung-Dong , Ahn Cheol-Woo , Cho Kyung-Hoon
Published: November 2019

We report a simple and effective method to obtain the magnetoelectric (ME) effect at zero magnetic bias field (HDC = 0), i.e., the self-biased ME (SME) effect, using an ME laminate composite clamped at its center with its free ends loaded with magnetic tip masses. The method exploits the shifting of the magnetic hysteresis loop of the ferromagnetic (FM) layer of the laminate induced by a preapplied magnetic field (Hp) along the longitudinal direction. The optimum magnetic-field strength corresponding to the maximum of the ME voltage coefficient (αME) vs HDC curve was calculated using equations derived from correlations of magnetic coefficients. In experiments involving the laminate with an FM/ferroelectric/FM symmetrical structure, the strength of Hp was tuned to the optimum value, shifting the αME vs HDC curve along the HDC axis enough to obtain the maximum αME at HDC = 0 (αSME). To further enhance αSME, an asymmetric configuration of the laminate was designed using two different FM materials having piezomagnetic coefficients with opposite signs. The ME laminate with the asymmetrical structure exhibited a large αSME of 55.7 V cm−1 Oe−1 at its bending resonance frequency.
Quasistatic growth of bubbles in a gelatin gel under dissolved-gas supersaturation
Authors: Ando Keita , Shirota Eriko
Published: November 2019

We theoretically and experimentally study the quasistatic growth of bubbles in a gelatin gel under dissolved-gas supersaturation in order to examine the role of the gel elasticity in the mass-diffusion-driven process. First, we model the diffusion-driven bubble growth with the classical Epstein-Plesset approach for quasistatic bubble growth, accounting for elasticity of the medium surrounding the bubbles. Next, we devise an experimental technique to visualize the bubble growth in an air-supersaturated gel of different gelatin concentrations and to obtain the growth rate of the bubble. We show, from comparisons between the theory and experiments, that the bubble growth is hindered by the gel elasticity.
Late-onset vanishing testis-like syndrome in a 38,XX/38,XY agonadic pig (Sus scrofa)
Authors: Vilchis Felipe , Mares Lizette , Chávez Bertha , Paredes Arcadio , Ramos Luis
Published: November 2019

Here we describe the case of a pig with intersex traits including ambiguous external genitalia, sex chromosome abnormalities and a late-onset vanishing testis-like syndrome. It was identified shortly after birth by presenting a predominantly female phenotype with two large scrotal masses resembling testes. The karyotype is 38,XX (53%)/38,XY (47%). Sex steroid levels were undetectable at 1 and 7 months old, whereas circulating cortisol levels were typical. DNA studies excluded gene alterations in sex-determining region Y (SRY), dosage-sensitive sex reversal-congenital adrenal hypoplasia critical region on the X chromosome protein 1 (DAX1), SRY-related high mobility group-box gene 9 (SOX9), nuclear receptor subfamily 5, group a, member 1 (NR5A1), nuclear receptor subfamily 3, group c, member 4 (NR3C4) and steroid 5-alpha-reductase 2 (SRD5A2). At 8 months of age the XX/XY pig evinced delayed growth; however, the most striking phenotypic change was that the testes-like structures completely vanished in a 2–3-week period. The internal genitalia were found to consist of a portion of a vagina and urethra. No fallopian tubes, uterus or remnants of Wolffian derivatives were observed. More importantly, no testes, ovaries, ovotestis or gonadal streaks could be identified. The XX/XY sex chromosome dosage and/or overexpression of the DAX1 gene on the X chromosome in the presence of a wild-type SRY gene may have caused this predominantly female phenotype. This specimen represents an atypical case of 38,XX/38,XY chimeric, ovotesticular disorder of sex development associated with agonadism.
Le développement de l’expression du genre grammatical en français L2
Authors: Edmonds Amanda
Published: November 2019

Les recherches portant sur l’acquisition de l’expression du genre grammatical en français langue seconde (L2) nous montrent, entre autres, que les apprenants réussissent plus souvent à marquer le genre avec un nom masculin (vs. un nom féminin) et sur les déterminants plutôt que sur les adjectifs. En revanche, il n’est pas clair si ces tendances générales s’appliquent de la même manière à l’ensemble des noms, adjectifs et déterminants concernés. En d’autres termes, nous pouvons nous demander à quel point l’expression du genre grammatical est déterminée par des spécificités lexicales. Est analysée, dans cette étude, l’évolution du marquage en genre produit par un groupe de 20 apprenants britanniques du français L2 sur une période de 21 mois. Des productions orales et écrites recueillies à trois périodes différentes ont été analysées, et le marquage en genre avec cinq noms féminins fréquents –chose, famille, maison, nourriture, vie – a fait l’objet d’une étude approfondie. Les résultats montrent que l’expression du genre grammatical se développe différemment avec ces cinq noms, résultat qui est interprété à l’aide des approches basées sur l’usage.
The production of geminates in Italian-dominant bilinguals and heritage speakers of Italian
Authors: Einfeldt Marieke , van de Weijer Joost , Kupisch Tanja
Published: November 2019

This study examines cross-linguistic influence (CLI) in adult Italian-German bilinguals based on the production of gemination, a phenomenon that exists in Italian but not in German. We analyzed the spontaneous Italian speech of two groups of Italian-German bilinguals (heritage speakers of Italian and Italian-dominant bilinguals) and a monolingual Italian control group. The results show that the geminates produced by the speakers in both bilingual groups were longer than their singletons. From this it seems that gemination is not affected by CLI. Based on our results, we discuss whether CLI is determined by (1) markedness, (2) frequency of Italian input during acquisition, (3) language dominance or (4) relevance (e.g. phonemic status), concluding that the latter is most crucial.
Réseaux sociaux et développement linguistique
Authors: Arvidsson Klara , Lundell Fanny Forsberg , Bartning Inge
Published: November 2019

Cette étude longitudinale contribue aux recherches sur l’acquisition d’une langue seconde (L2) dans le contexte de
séjour linguistique à l'étranger (Study Abroad), où l’on s’intéresse de plus en plus à comprendre comment les facteurs
non-linguistiques interagissent avec le développement linguistique. Elle étudie le rôle de la nature du réseau social (au sens
sociologique) de l’apprenant dans le développement de la production orale en français L2 chez deux étudiants suédois qui passent
un semestre en France et dont les niveaux d’intégration dans la communauté de la langue cible (LC) s’opposent. L’analyse suggère
qu’un réseau social plus riche en relations en LC confère un avantage supplémentaire en ce qui concerne le développement du
répertoire des expressions polylexicales (EPL) de l’apprenant, mais non pas le développement de l’exactitude grammaticale, de la
diversité lexicale et de l’usage des marqueurs discursifs. Ainsi, l’étude vient partiellement à l’appui de la supposition que le
réseau social de l’apprenant explique la variation individuelle dans le développement linguistique.
Effect of heat treatment on microstructure and mechanical properties of Cu–6.9Ni–2.97Al–0.99Fe–1.06Mn alloy
Authors: Yang Ran , Wen Jiuba , Zhou Yanjun , Song Kexing , Niu Liye , Guo Huiwen , Yu Yan
Published: November 2019

The effect of heat treatment on the mechanical properties and microstructures of Cu–6.9Ni–2.97Al–0.99Fe–1.06Mn alloys was investigated. The results show that the microstructure of the as-cast alloy mainly consists of an alpha-copper matrix and γ-phase Ni3Al particles. The microstructure of the alloy after solution treatment at 950°C for 2 h is a single-phase alpha-copper supersaturated solid solution and the second-phase strengthening disappears. After ageing treatment at 550°C for 6 h, the γ-phase particles are fully precipitated, and the mechanical properties of the alloy are significantly improved. The tensile strength is increased from 305 to 588 MPa. Quasi-cleavage fracture with shallow dimples appeared in the Cu–6.9Ni–2.97Al–0.99Fe–1.06Mn alloy aged at 550°C for 6 h.
Role of gender and urban/rural divide in language shift in Pakistani Punjab
Authors: John Asher
Published: November 2019

Despite positive attitudes towards Punjabi in the urban areas of Pakistani Punjab, there is a shift towards the Urdu language in almost all domains. This study shows that significant differences in language choices are found between the rural/urban and male/female residents of Punjab province. Urban females are leading this shift in spite of their positive attitudes towards Punjabi. Urban females use Punjabi very little and only in the home domain. In social and business domains Punjabi language is almost non-existent among urban, educated, and middle class females. The shift from Punjabi to Urdu in the educated urban female group is almost complete in spite of their positive attitudes towards their ancestral language. Urban males use more Punjabi than the urban females. In rural areas Punjabi is still used in most domains by both males and females.
Enhancement of droplet ejection from molten and liquid plasma-facing surfaces by the electric field of the sheath*
Authors: Holgate J T , Coppins M
Published: November 2019

Maintaining the stability of a liquid surface in contact with a plasma is of crucial importance in a range of industrial and fusion applications. The most fundamental feature of a plasma-surface interaction, the formation of a highly-charged sheath region, has been neglected from the majority of previous studies of plasma-liquid interactions. This paper considers the effect of the electric field of the sheath on the ejection of micron-scale droplets from bubbles bursting at the liquid surface. A numerical simulation method, based on the ideal electrohydrodynamic model, is introduced and validated against the well-known Taylor cone theory. This model is then used to include the electrical effects of the sheath in simulations of bubble bursting events at a plasma-liquid interface. The results show a significant enhancement in droplet ejection at modest electric fields of between 10% and 20% of the critical field strength required for a solely electrohydrodynamic instability. This finding is in good qualitative agreement with experimental observations and its importance in a wide range of fusion and atmospheric-pressure plasma-liquid interactions is discussed. The inclusion of sheath physics in future studies of plasma-liquid interactions is strongly advocated.
Exploring the energy frontier with deep inelastic scattering at the LHC
Authors: Brüning Oliver , Klein Max
Published: November 2019

A proposal is described for complementing the intense, high energy proton and ion beams of the Large Hadron Collider (LHC) with a novel electron energy recovery linac (ERL) to provide a next generation electron-hadron collider facility of more than 1 TeV center-of-mass energy. This Large Hadron Electron Collider (LHeC) will substantially extend the kinematic range covered by the first ep collider, HERA, and surpass its luminosity by a factor of several hundreds. This configuration will be a microscope for the substructure of matter with unprecedentedly clean resolution and a facility for new physics in the Higgs, strong interaction and electroweak sector with a strong discovery potential. The paper also describes the accelerator design and its main characteristics. As such it had been submitted to the deliberations on the future of European particle physics.
Thermal instability and non-equilibrium in solar coronal loops: from coronal rain to long-period intensity pulsations
Authors: Antolin P
Published: November 2019

The complex interaction of the magnetic field with matter is the key to some of the most puzzling observed phenomena at multiple scales across the Universe, from tokamak plasma confinement experiments in the laboratory to the filamentary structure of the interstellar medium. A major astrophysical puzzle is the phenomenon of coronal heating, upon which the most external layer of the solar atmosphere, the corona, is sustained at multi-million degree temperatures on average. However, the corona also conceals a cooling problem. Indeed, recent observations indicate that, even more mysteriously, like snowflakes in the oven, the corona hosts large amounts of cool material termed coronal rain, hundreds of times colder and denser, that constitute the seed of the famous prominences. Numerical simulations have shown that this cold material does not stem from the inefficiency of coronal heating mechanisms, but results from the specific spatio-temporal properties of these. As such, a large fraction of coronal loops, the basic constituents of the solar corona, are suspected to be in a state of thermal non-equilibrium (TNE), characterised by heating (evaporation) and cooling (condensation) cycles whose telltale observational signatures are long-period intensity pulsations in hot lines and thermal instability-driven coronal rain in cool lines, both now ubiquitously observed. In this paper, we review this yet largely unexplored strong connection between the observed properties of hot and cool material in TNE and instability and the underlying coronal heating mechanisms. Focus is set on the long-observed coronal rain, for which significant research already exists, contrary to the recently discovered long-period intensity pulsations. We further identify the outstanding open questions in what constitutes a new, rapidly growing field of solar physics.
Wide color gamut switchable autostereoscopic 3D display based on directional quantum-dot backlight*
Authors: Xu Bin , Li Xue-Ling , Wang Yuan-Qing
Published: November 2019

A switchable autostereoscopic 3-dimensional (3D) display device with wide color gamut is introduced in this paper. In conjunction with a novel directional quantum-dot (QD) backlight, the precise scanning control strategy, and the eye-tracking system, this spatial-sequential solution enables our autostereoscopic display to combine all the advantages of full resolution, wide color gamut, low crosstalk, and switchable 2D/3D. And also, we fabricated an autostereoscopic display prototype and demonstrated its performances effectively. The results indicate that our system can both break the limitation of viewing position and provide high-quality 3D images. We present two working modes in this system. In the spatial-sequential mode, the crosstalk is about 6%. In the time-multiplexed mode, the viewer should wear auxiliary and the crosstalk is about 1%, just next to that of a commercial 3D display (BENQ XL2707-B and View Sonic VX2268WM). Additionally, our system is also completely compatible with active shutter glasses and its 3D resolution is same as its 2D resolution. Because of the excellent properties of the QD material, the color gamut can be widely extended to 77.98% according to the ITU-R recommendation BT.2020 (Rec.2020).
Towards error categorisation in BCI: single-trial EEG classification between different errors
Authors: Wirth C , Dockree P M , Harty S , Lacey E , Arvaneh M
Published: November 2019

Objective. Error-related potentials (ErrP) are generated in the brain when humans perceive errors. These ErrP signals can be used to classify actions as erroneous or non-erroneous, using single-trial electroencephalography (EEG). A small number of studies have demonstrated the feasibility of using ErrP detection as feedback for reinforcement-learning-based brain-computer interfaces (BCI), confirming the possibility of developing more autonomous BCI. These systems could be made more efficient with specific information about the type of error that occurred. A few studies differentiated the ErrP of different errors from each other, based on direction or severity. However, errors cannot always be categorised in these ways. We aimed to investigate the feasibility of differentiating very similar error conditions from each other, in the absence of previously explored metrics. Approach. In this study, we used two data sets with 25 and 14 participants to investigate the differences between errors. The two error conditions in each task were similar in terms of severity, direction and visual processing. The only notable differences between them were the varying cognitive processes involved in perceiving the errors, and differing contexts in which the errors occurred. We used a linear classifier with a small feature set to differentiate the errors on a single-trial basis. Main results. For both data sets, we observed neurophysiological distinctions between the ErrPs related to each error type. We found further distinctions between age groups. Furthermore, we achieved statistically significant single-trial classification rates for most participants included in the classification phase, with mean overall accuracy of 65.2% and 65.6% for the two tasks. Significance. As a proof of concept our results showed that it is feasible, using single-trial EEG, to classify these similar error types against each other. This study paves the way for more detailed and efficient learning in BCI, and thus for a more autonomous human-machine interaction.
The effect of temperature distribution in the lunar mantle on joint inversion of geochemical (bulk chemical composition), seismic and selenodetic (GRAIL and LLR) data
Authors: Kronrod E , Matsumoto K , Kuskov O , Kronrod V , Yamada R , Kamata S
Published: November 2019

Using Bayes inversion approach and Markov chain Monte Carlo method (MCMC), we studied the effect of temperature distribution in the lunar mantle on the chemical composition (concentrations of main oxides Al2O3, FeO, MgO) and seismic velocities in the mantle. The temperature and concentrations of the main oxides were calculated with thermodynamic methods for phase relations and physical properties modeling in the system CaO-FeO-MgO-Al2O3-SiO2 using the Gibbs free energy minimization method. A set of geophysical data was used for the inversion (slenodetic: mean radius (R), mass (M), normalized moment of inertia (Is / MR2), Love number k2 and seismic data – seismic travel times (TT). The Moon is assumed to be viscoelastic, spherically symmetric, and consists of nine layers with constant physical properties in each layer: megaregolith, crust, four mantle layers, low viscosity zone (LVZ), liquid outer core and solid inner core. Physical properties in each zone are assumed to be constant. The division of the mantle into layers was performed in accordance with the seismic model. The concentrations of the main oxides were set equal in the three upper layers of the mantle; the magma ocean model was used to calculate oxide concentrations in the lower mantle.

Two types of geochemical models of bulk composition of the Moon were considered: 1 -models with similar to silicate Earth Al2O3 content, 2 - models enriched in Al2O3 (> 4.5 wt.%). Linear temperature profiles in the mantle were considered, the temperature was set in the middle of the mantle layers at depths of 150, 375, 625 and 1000 km. At a depth of 150 km, the temperature was set at 600 ° C; in the lower mantle, it varied from 1000 to 1400 ° C. For both types of models and wide temperature range in the lower mantle, it is possible to obtain distributions of the main oxides concentrations in the mantle which are consistent with a given Al2O3 and FeO bulk composition. Calculated concentrations and velocities in the mantle are in good agreement with the results obtained by other authors.
Analysis of correction of asteroid Apophis’ orbit providing its collision with the Moon
Authors: Ivashkin V V , Stikhno C A
Published: November 2019

In case of possible asteroid Apophis’ collision with the Earth, we estimate characteristics of such orbit correction, which will provide asteroid’s deflection from the Earth and its collision with the Moon. By this way, we will avoid any danger from this asteroid’s close approaches with the Earth in the future. We developed a method for searching these trajectories providing collision with the Moon depending on date of correction. Such trajectories were found for next two decades. Parameters for one-impulse correction were estimated. Additionally an optimization of correction impulse was performed based on the time of collision with the Moon. Parameters of Apophis’ collision with the Moon were calculated.
Nonlinear visco-elastic-plastic model of impact
Authors: Borovin G K , Lapshin V V
Published: November 2019

A nonlinear model of the impact of a visco-elastic-plastic body against a fixed obstacle is investigated. This model is reduced to a nonlinear second-order differential equation. The solution of the body motion equation using the special Lambert function is obtained. Within the framework of the model, an elastic and absolutely inelastic impact are possible. In the case of an elastic impact, the coefficient of restitution decreases when of the impact velocity is increasing.
The construction of the portrait of the correlation dimension of an attractor in the boundary layer of Earth’s atmosphere
Authors: Dmitrenko A V
Published: November 2019

The construction of the portrait of the correlation dimension of the attractor in the boundary layer of Earth’s atmosphere on the basis of the new theory of stochastic hydrodynamics is presented. This theory is based on the theory of stochastic equations of continuum laws and equivalence of measures between random and deterministic movements. Using these equations a new formula for the correlation dimension of the attractor is applying for conditions in the boundary layer of Earth’s atmosphere.
On two experiments with falling chains
Authors: Domnyshev A A , Kalinichenko V A , Shkapov P M
Published: November 2019

The article considers paradoxical results of metal chain movement that do not agree with classical theoretical models. We present the results of experiments with the falling U-folded chain and with chain fountain. The velocity and acceleration of chain motion were measured and estimated. The trajectory of the fountaining chain links has been investigated experimentally. A comparison of the experimental data with existing theoretical models is made.
Free motion of the deformable Earth’s pole
Authors: Yu Barkin M , Bondarenko V V , Perepelkin V V
Published: November 2019

Free motion of the Earth pole is studied on the base of Euler-Liouville dynamic equations of the deformable Earth motion around its center of mass. The dependence of the external influence amplitude from dissipation coefficients is found for the stationary mode of the Earth pole oscillations on the Chandler frequency and external disturbance with the Chandler frequency. It is shown that the Chandler wobble amplitude is sensitive to the difference between the Chandler frequency and those close to it and to the nonlinear dissipation coefficients. The stability conditions of the steady Chandler wobble are defined.
Mechanics of stability’s loss in the skiing turning
Authors: Legotin S D , Rivlin A A
Published: November 2019

The article discusses the mechanics of the loss of an athlete transverse steady state when performing a ski turn. The analysis of the loss of stable position of the rod model of the mechanical system "skier-skis" in the lateral sliding of skis and falling in the frontal plane was performed. The conditions and possible ways of preventing the skier from falling and restoring a stable position during turn are quantified.
Determination of constraint stabilization parameters with multiple roots of characteristic equation
Authors: Kaspirovich I E , Askarova K Z , Mukharlyamov R G
Published: November 2019

During a numerical integration of motion equations of a constrained mechanical system effect of deviations from initial data can be neglected with the help of Baumgarte stabilization method. According to this method first time derivatives of constraint equations are not considered as first integrals and are equated to an arbitrarily linear form of constraints themselves. The coefficients of these forms are called perturbation parameters. So, the problem of constraint stabilization is reduced to a problem of finding an appropriate range of perturbation parameters’ values. This problem can be solved by obtaining these values with the help of stability conditions. The procedure of evaluation is getting even more easier if the perturbation coefficients correspond to the multiple root case of its characteristic equation.