bluuebunny/crossref_metadata_2025 huggingface dataset:
Nonlinear global gyrokinetic delta-f turbulence simulations in a quasi-axisymmetric stellarator
Authors: Cole M. D. J. , Moritaka T. , Hager R. , Dominski J. , Ku S. , Chang C. S.
Published: April 2020

We use the global gyrokinetic stellarator code XGC-S to look at turbulence physics in geometry of the proposed quasi-axisymmetric stellarator, QUASAR. The XGC-S code is first verified for nonlinear simulations of ion temperature gradient-driven turbulence by a successful benchmark with the established nonlinear tokamak code XGC1 in a CYCLONE-like tokamak case. We then apply the XGC-S code to QUASAR for nonlinear turbulence physics. We find that the highly poloidally localized linear mode gives way to a more evenly distributed nonlinear turbulent structure. Meanwhile, the radial extent of the mode increases and occupies a large fraction of the volume, despite the initially localized temperature profile, as the profiles relax.
Microscale, bendable thermoreflectance sensor for local measurements of the thermal effusivity of biological fluids and tissues
Authors: Xie Xu , Diao Zhu , Cahill David G.
Published: April 2020

Measurements of the thermal transport properties of biological fluids and tissues are important for biomedical applications such as thermal diagnostics and thermal therapeutics. Here, we describe a microscale thermoreflectance sensor to measure the thermal effusivity of fluids and biological samples in a minimally invasive manner. The sensor is based on ultrafast optical pump–probe techniques and employs a metal-coated optical fiber as both a photonic waveguide and a local probe. Calibration of the sensor with five liquids shows that the percentage deviation between experimentally measured effusivity and literature values is on average <3%. We further demonstrate the capability of the sensor by measuring the thermal effusivity of vegetable oil, butter, pork liver, and quail egg white and yolk. We relate the thermal effusivity of the samples to their composition and water content, and establish our technique as a powerful and flexible method for studying the local thermal transport properties of biological materials.
Mesoscopic modeling of the mechanically tunable electrical conductivity of ZnO varistors
Authors: Taylor K. A. , Gjonaj E. , Zhou Z. , Xu B.
Published: April 2020

An electromechanically coupled model for the simulation of electric current flow in ZnO varistors is presented. The model is based on an equivalent circuit representation of the varistor microstructure, where the grain boundaries are modeled as nonlinear resistors in the circuit. This approach extends on previous circuit models by including the effect of mechanical stress on grain boundary conductivity. The 3D mechanical stress distribution in the material is calculated by the finite element method. Using this distribution, the electrical resistance of each grain boundary is determined by applying a self-consistent model for the trapped interface charge induced by piezoelectric polarization. Finally, the electric current flow patterns and the bulk conductivity of the material are computed using the nonlinear circuit model. The simulated IV-characteristics reveal a significant sensitivity of electrical conductivity to applied stress. For 2D and 3D ZnO varistor models, the simulations demonstrate the effect of current concentration along thin conducting paths depending on microstructure properties and on the mechanical stress condition of the material.
Frequency enhancement and power tunability in tilted polarizer spin-torque nano-oscillator
Authors: Arun R. , Gopal R. , Chandrasekar V. K. , Lakshmanan M.
Published: April 2020

In the absence of an applied magnetic field, a spin-torque nano-oscillator with a tilted polarizer is studied using numerical simulations of the associated Landau–Lifshitz–Gilbert–Slonczewski equation. We find considerable enhancement of frequencies by tilting the polarizer out-of-plane appropriately. Also, we observe improved tunability of frequencies of oscillations from ∼15GHz to ∼75GHz and increments in the power spectral density by current and tilt angles. In addition, our findings and insights pave a simple way for implementation of nanoscale level microwave generators.
Selective dynamics in polymeric materials: Insights from quasi-elastic neutron scattering spectroscopy
Authors: Ashkar Rana
Published: April 2020

Polymeric materials exhibit a rich hierarchy of dynamics from fast sub-molecular motions to collective segmental relaxations and slow chain diffusion. Such dynamical hierarchy dictates that the performance of polymeric materials is tightly linked to fast molecular dynamics, necessitating a thorough understanding of the dynamic behavior of polymers on the nanoscale. Recent advances in the synthesis of polymer composites with nanoscale fillers further amplify the need to probe polymer dynamics over spatial and temporal nanoscales to achieve reliable engineering of materials with well-defined properties. This tutorial focuses on the efficacy of neutron spectroscopy techniques, combined with judicious hydrogen/deuterium labeling, in selectively probing local and collective dynamics that underlie macroscopic properties in polymeric materials with varying degrees of complexity.
Size dependent chaotic spin–orbit torque induced magnetization switching of a ferromagnetic layer with in-plane anisotropy
Authors: Chen BingJin , Chung Hong Jing , Lim Sze Ter
Published: April 2020

Understanding the magnetization switching dynamics induced by the spin–orbit torque (SOT) in a ferromagnetic layer is crucial to the design of the ultrafast and energy-saving spin–orbit torque magnetic random access memory. Here, we investigate the SOT switching dynamics of a ferromagnetic layer with in-plane anisotropy with various elliptic sizes in different easy-axis orientations using micro-magnetic simulations. The reliable and ultrafast magnetization switching can be realized by tilting the easy axis to an optimum angle with respect to the current injecting direction. The switching time, in general, decreases smoothly with an increasing current density, and the optimum tilting angle is determined for small device sizes with width smaller than 100 nm. This optimum angle is a small angle deviating from a case when the in-plane easy axis is orthogonal to the current direction. It depends on the size, the current density, and also the damping constant. However, with the device increasing to a certain size (e.g., 250 nm), especially at small tilting angles, we observe chaotic switching behavior where the switching times fluctuate locally with the current density. We attribute this size dependent chaotic switching phenomenon to the nucleation and formulation of complex multi-domains during switching. This chaotic phenomenon can be alleviated by enhancing the field-like torque in the device and thus decreasing the switching times. Consequently, the shape and size of the devices should be carefully taken into account while designing a practical fast switching and low power SOT device with in-plane anisotropy.
Effects of pore size on water dynamics in mesoporous silica
Authors: Yamada Steven A. , Hung Samantha T. , Thompson Ward H. , Fayer Michael D.
Published: April 2020

Water confined in mesoporous silica plays a central role in its many uses ranging from gas sorption to nanoconfined chemical reactions. Here, the influence of pore diameter (2.5–5.4 nm) on water hydrogen bond (H-bond) dynamics in MCM41 and SBA15 mesoporous silicas is investigated using femtosecond infrared vibrational spectroscopy and molecular dynamics simulations on selenocyanate (SeCN−) anions dissolved in the pores. As shown recently, SeCN− spectral diffusion is a reliable probe of surrounding water H-bond structural motions. Additionally, the long CN stretch vibrational lifetime facilitates measurement of the full range of confined dynamics, which are much slower than in bulk water. The simulations shed light on quantitative details that are inaccessible from the spatially averaged observables. The dependence of SeCN− orientational relaxation and that of spectral diffusion on the distance from the silica interface are quantitatively described with an exponential decay and a smoothed step-function, respectively. The distance-dependence of both quantities is found to be independent of the diameter of the pores, and the spatial distribution of SeCN− is markedly non-uniform, reaching a maximum between the interface and the pore center. The results indicate that the commonly invoked two-state, or core–shell, model is a more appropriate description of spectral diffusion. Using these insights, we model the full time-dependence of the measured dynamics for all pore sizes and extract the “core” and “shell” dynamical correlation functions and SeCN− spatial probability distributions. The results are critically compared to those for water confined in reverse micelles.
Secondary instability of Mack mode disturbances in hypersonic boundary layers over micro-porous surface
Authors: Xu Jiakuan , Liu Jianxin , Mughal Shahid , Yu Peixun , Bai Junqiang
Published: April 2020

In laminar hypersonic boundary layers, it is known that secondary instability plays a crucial role in transition to turbulence. The secondary instability usually includes the fundamental mode, the subharmonic mode, and the detuned mode. Considerable research exists on the secondary instability mechanism in hypersonic boundary layers with the smooth wall condition. The topic of using micro-porous surfaces for disturbance stabilization has recently drawn interest. The stabilization and, thus, a possible delay in the transition arise due to a reduction in the growth rate of the primary Mack mode by the porous surface. This paper focuses on investigating whether the secondary instability mechanism of Mack modes can also be affected by a surface porosity condition. It is known that the primary Mack mode linear disturbances are changed significantly on the porous surface, and how it subsequently influences the secondary instability of the modified time varying basic flow is our concern. The analysis demonstrates that on the porous surface, as the amplitude of the primary Mack mode increases, the fundamental mode is not stable. Instead, the fundamental mode amplifies rapidly with increasing primary amplitudes. At larger secondary instability spanwise wavenumbers, when the primary amplitude exceeds a certain threshold value, the fundamental modes surpass the subharmonic modes and dominate the secondary instability. However, when the spanwise wavenumber is relatively small, especially at the spanwise wavenumber corresponding to the maximum growth rate of the subharmonic mode, the fundamental modes are weakened and lose their dominant position. We find that corresponding to different amplitudes of primary Mack mode disturbances affected by the porosity parameters, there are no strongly preferred interaction modes that dominate the secondary instability; this contrasts with smooth wall findings. We further find that the larger the pore size or porosity, the more severe the suppression of the fundamental mode.
Stability of electrically conducting liquid flow driven by a rotating magnetic dipole in a ring channel
Authors: Grants Ilmārs , Berenis Didzis
Published: April 2020

The stability of electrically conducting liquid flow in a cylindrical ring channel is studied numerically. The flow is driven by a rotating magnetic dipole placed at the ring’s center. Depending on ring’s width, two distinct flow regimes are observed. In a narrow ring, the flow itself and its instability resemble the related rotating magnetic field driven flow in a cylinder. This changes in a wide ring when an intense radial jet develops on the midplane. Within this jet, the driving magnetic force is overwhelmed by inertial and viscous forces similar to how it occurs in the boundary layer flow. The instability develops as an azimuthally periodic wave-like deformation of this jet. Non-uniform driving force and the viscous boundary layer at the inner side wall are supposed as the main ingredients of the jet formation.
Temperature-dependent current-voltage characteristics of
β
-Ga2O3 trench Schottky barrier diodes
Authors: Jian Zhe (Ashley) , Mohanty Subhajit , Ahmadi Elaheh
Published: April 2020

Temperature-dependent behavior of regular and trench Ni/β-Ga2O3 (001) Schottky barrier diodes (SBDs) was studied. Current–Voltage (I–V) characteristics, ideality factor, and barrier height of trench SBDs were compared with those of regular SBDs at temperatures ranging from 100 K to 650 K. The trench SBDs showed a superior performance to regular SBDs. At elevated temperatures (as high as 650 K), the trench SBDs maintained a high ON/OFF current ratio (105), which is four orders of magnitude higher than that in the regular diodes. The current–voltage characteristics of the trench SBDs were recovered when the sample was cooled to room temperature after high temperature measurements, whereas the I–V characteristics of the regular SBDs were degraded. The breakdown voltage (BV) was also measured on as-fabricated devices and after high temperature ramp up to 650 K. We observed a reduction in maximum achieved BV from 1084 V to 742 V on the trench SBDs and from 662 V to 488 V on regular SBDs, respectively, after temperature-dependent measurements.
Visualization of methane hydrate decomposition interface and analyses of decomposition rate and interfacial configuration
Authors: Kanda Yuki , Okajima Junnosuke , Maruyama Shigenao , Komiya Atsuki
Published: April 2020

Composed of methane gas and cage-like water molecules, methane hydrate is expected to have innovative engineering applications, such as gas transportation. In this study, a methane hydrate decomposition interface is visualized qualitatively, and the decomposition rate is discussed. To clarify the decomposition mechanism, consideration is given to the dynamic decomposition interface and the variation of the decomposition rate. In the present experiment, methane hydrate is formed around a water droplet and decomposed by depressurization in the gas phase, the dynamic variation of the decomposition interface is observed precisely using a high-resolution camera, and three different depressurization conditions are used to confirm the interfacial change. It is found that the decomposition rate and dynamic shape change of the decomposition interface depend on the difference between the equilibrium pressure and that of the gas phase. In addition, the decomposition time is discussed using the decomposition model, and it is estimated that the present experimental decomposition rate corresponds to a lower activation energy for decomposition compared with that of the model by other authors. It is assumed that the decomposition proceeds under nearly reaction-limited conditions. Additionally, the interfacial deformation and collapse are observed in the case of pressure reduction near the equilibrium pressure, and validation is provided by a numerical simulation considering the heat and mass transfer near the interface. The numerical results suggest that the decomposition is affected by the interfacial configuration and the nearby temperature and concentration distributions.
Four wave-mixing in a microstrip kinetic inductance travelling wave parametric amplifier
Authors: Goldstein Samuel , Kirsh Naftali , Svetitsky Elisha , Zamir Yuval , Hachmo Ori , de Oliveira Clovis Eduardo Mazzotti , Katz Nadav
Published: April 2020

Superconducting quantum circuits are typically operated at low temperatures (mK), necessitating cryogenic low-noise, wideband amplifiers for signal readout ultimately also compatible with room temperature electronics. While existing implementations partly meet these criteria, they suffer from certain limitations, such as rippled transmission spectra or limited dynamic range, some of which are caused by the lack of proper impedance matching. We develop a microstrip kinetic inductance traveling wave amplifier, exploiting the nonlinear kinetic inductance of tungsten-silicide for wave-mixing of the signal and a pump, and engineer the impedance to 50 Ω, while decreasing the phase velocity, with benefit for the amplification. Despite losses, pumping on our device amplifies the signal by 15 dB over a 2 GHz bandwidth.
Engineering lattice metamaterials for extreme property, programmability, and multifunctionality
Authors: Jia Zian , Liu Fan , Jiang Xihang , Wang Lifeng
Published: April 2020

Making materials lightweight while attaining a desirable combination of mechanical, thermal, and other physical properties is the “holy grail” of material science. Lattice materials, because of their porous structures and well-defined unit cell geometries, are suitable candidates to achieve lightweight with precisely tailored material properties. Aided by additive manufacturing techniques, a variety of lattice metamaterials with exceptional and unusual properties have been fabricated recently, yet, the rational designs of lattice metamaterials with programmability and multifunctionality are still challenging topics. In this perspective, we identify three emerging directions for lattice metamaterials: (1) developing architected lattice metamaterials with extreme and unusual properties that are non-typical in bulk materials, (2) designing lattice metamaterials with programmable mechanical properties that respond differently at different environments, loading paths, or controls, and (3) exploiting lattice metamaterials with multifunction, including tailorable thermal, mechanical, optical, piezoelectric, and negative-index material properties. These emergent directions portend the transitioning of lattice metamaterials from the stage of conventional materials to smart, adaptive, and versatile materials, which provide solutions to realistic problems in transport systems, wearable devices, and robotics, and continue to push the boundary of possibilities of architected metamaterials.
Transposon mobilization in the human fungal pathogen
Cryptococcus
is mutagenic during infection and promotes drug resistance in vitro
Authors: Gusa Asiya , Williams Jonathan D. , Cho Jang-Eun , Averette Anna Floyd , Sun Sheng , Shouse Eva Mei , Heitman Joseph , Alspaugh J. Andrew , Jinks-Robertson Sue
Published: April 2020

Significance

The incidence of infections due to fungal pathogens has dramatically increased in human populations with weakened or suppressed immune systems. Understanding how organisms rapidly adapt during human infection to enhance virulence and evolve drug resistance is important for developing effective treatments. We find that transposon mobilization in the human pathogen
Cryptococcus
causes genomic mutations in a murine model of infection and promotes resistance to antifungal drugs in vitro. Thermotolerance is a key virulence determinant for pathogenic fungi during the environment-to-host transition, and we demonstrate that a temperature increase is sufficient to trigger transposon mobilization in vitro. The link between temperature stress and transposon-associated mutations may significantly impact adaptation to the host during infection, including the acquisition of drug resistance.
The licensing of wh-in-situ questions
Authors: González Carolina , Reglero Lara
Published: April 2020

This project investigates the intonational
characteristics of information-seeking wh-in-situ and yes/no
questions in Spanish. Data from eight Spanish-Basque bilinguals show
that while the former tend to display final rising contours, the
latter are primarily circumflex, especially in participants with
higher Basque dominance. Our results provide evidence that both
question types are licensed by a null intonational morpheme, as
proposed by Cheng and Rooryck
(2000) for French. However, this morpheme in Spanish is
encoded as an elevated high tone, rather than a rising contour.
Furthermore, Spanish wh-in-situ questions show higher tonal ranges
than in French (Déprez et al.
2013). We suggest that this results from focus assignment
on the wh-word and its obligatory placement at the end of the
intonational phrase.
The aspectual structure of the adjective
Authors: García-Pardo Alfredo , Menon Mythili
Published: April 2020

This paper argues that the stage-level and
individual-level distinctions for adjectival predicates, diagnosed
in Spanish by the copulas ser and
estar, can be derived by positing a sortal
distinction in the temporal arguments in the syntax: The temporal
argument of individual-level adjectives denotes time intervals,
whereas the time argument of stage-level adjectives denotes time
instants. We provide evidence from the (un-)acceptability of certain
temporal modifiers, the progressive, and lifetime effects. We
furthermore show how our account can also explain other instances of
the ser and estar distribution
beyond adjectives, such as verbal and adjectival passives and
locative constructions with and without eventive subjects.
Syntactic and prosodic marking of subject focus in American
English and Peninsular Spanish
Authors: Sánchez-Alvarado Covadonga
Published: April 2020

The aim of the present study is to provide an account
of the different strategies, both syntactic and prosodic, employed
by American English and Peninsular Spanish speakers in subject focus
marking. Data obtained through parallel experimental designs
revealed that prosodic marking of focus in-situ is possible in both
languages both for informational and contrastive focus. Nonetheless,
in the expression of contrastive focus Peninsular Spanish speakers
increase the use of clefting while American English speakers exploit
prosodic strategies like creaky voice. Differences in the pitch
range implemented on focalized subjects were against the posed
prediction. This study, nonetheless, contributes to the lacking
cross-linguistic comparisons of these two languages and explores the
interconnections between syntax and prosody.
Afro-Peruvian Spanish declarative intonation
Authors: Butera Brianna , Sessarego Sandro , Rao Rajiv
Published: April 2020

This study offers an analysis of Afro-Peruvian
Spanish (APS) declarative intonation. Our findings indicate that
this dialect presents intonational features that diverge from other
varieties of Spanish. It shows minimal downstepping across
utterances and a predominant use of the L+H* pitch accent, even in
prenuclear position, where L+>H* is more commonly cited in
neutral contexts. At intermediate phrase edges, the most common APS
boundary tone is L- rather than H-, which is usually employed in
other varieties to indicate the continuation of a thought. Our
results evidence a simplified set of phonological targets, which are
analyzed as the byproduct of SLA processes that were subsequently
conventionalized and nativized at the community level by later
generations of APS speakers.
Examining the (mini-) variable swarm in the Spanish of the
Southeast
Authors: Ronquest Rebecca E. , Michnowicz Jim , Wilbanks Eric , Cortes Claudia
Published: April 2020

The present investigation aims to facilitate our
understanding of Spanish in the Southeastern United States – a
region that despite its rapid growth over the last two decades, has
received little attention in the literature. Analyses of four
linguistic variables indicated that while second generation heritage
speakers produced significantly more English discourse markers than
first generation immigrants, realization of phonetic variables was
similar across groups. An examination of the overall patterns across
the four variables (i.e., “variable swarm”), however, suggests that
heritage speakers are beginning to integrate contact-induced
characteristics into their speech faster than immigrants do. By
examining multiple variables simultaneously, the present study
therefore offers important insight into the processes of new dialect
formation, convergence, and leveling in an understudied region.
Morphosyntactic integration of ideophones in Japanese and
Korean
Authors: Park Ji-Yeon
Published: April 2020

This study explores how the morphosyntactic integration
of ideophones differs between two registers of two ideophone-rich
languages, Japanese and Korean. Previous studies have demonstrated
that the iconicity and expressive power of ideophones in spoken
language are inversely correlated with their degree of grammatical
integration. Drawing on corpus data from spoken and written Japanese
and Korean, this paper argues that the morphosyntactic integration
of ideophones as measured by their verbalizability is greater (i) in
non-auditory domains than in the auditory domain, (ii) in spoken
than written discourse, and (iii) in Korean than in Japanese.
Pathways of de-iconization
Authors: Flaksman Maria
Published: April 2020

The present chapter addresses various issues of
de-iconization of iconic (mainly onomatopoeic) words, in particular,
in the course of their regular phonetic and semantic development.
These processes are described with an emphasis on word’s etymology,
examples being drawn from modern and ancient Germanic languages. The
chapter proposes a classification of various form transformations
that lead to de-iconization.
On the expressive and iconic value of enjambment from Homer to
Milton
Authors: Dainotti Paolo
Published: April 2020

Enjambment, the breaking of correspondence between meter
and syntax usually employed to avoid the monotony of verse-phrase,
is also, in some cases, exploited as an effective stylistic figure
to charge the diction with expressiveness at various levels. The aim
of my paper is to discuss the iconic expressiveness of enjambment in
epic poetry from Homer up to Milton and Tasso. I will analyse in
particular the striking type consisting of the postposition of a
single word in the next line, before a syntactic pause. This figure,
since it introduces a strong pause in reading, seems particularly
appropriate to stress significant words or to reinforce iconically
the semantics of verbs meaning a sudden, violent action, such as
that of falling down or throwing. The ‘chain’ of passages in which
the figure is employed with similar stylistic effects in different
literatures and languages sheds an important light on the
‘mechanisms’ of intertextuality, clarifying the impact and the
contribution of great Poets to the stylistic
repertoire of an entire poetic genre.
Crisscrossing James Joyce’s Ulysses
Authors: Ljungberg Christina
Published: April 2020

Chiasmus fundamentally involves iconicity. As a
bi-lateral symmetrical figure that can have both an ornamental and a
rhetorical function, it occurs on all levels of texts–sounds and
graphemes, words, sentences, lines, chapters and entire books as
well as on the narrative and on the conceptual level. The chiastic
mirror-image design in which the second part is balanced against the
first is however not limited to language but also appears in art and
architecture. As recent cognitive research has shown, chiasmus forms
an important strategy through its simple but unique design. This has
to do with its spatial shape and how the crisscrossing of lines and
paths that takes place in the X-figure is cognised, perceptually and
experientially – suggesting itself as the origin of human abilities
such as forming analogies and using conceptual integration. This is
what my contribution explores, with example from James Joyce’s
Ulysses.
Show me how you feel
Authors: Kendall Lia N. , Raffaelli Quentin , Todd Rebecca M. , Kingstone Alan , Cohn Neil
Published: April 2020

Visual representations are an ideal place to look at the
balance of iconicity and systematicity, given that visual images
often look like what they represent but also can be characterized
along a scale from highly photorealistic to highly schematic or
cartoony. Here we examine the contrast between different styles by
presenting participants with “visual morphology” of
upfixes – representations like hearts or
lightbulbs that float above faces – where the face and/or upfix are
either cartoony or photorealistic. Overall, we find that cartoony
images, relative to photorealistic images, are easier to process,
and therefore demand less attention and facilitate responding. We
argue that these results support the view that drawings, and visual
morphology, draw on schematic knowledge stored in long-term
memory.
Monocollocable words
Authors: Čermák František
Published: April 2020

How often do people, even native speakers, wonder, on hearing a
familiar proverb, such as Much Ado about Nothing, what ado in this proverb
really means? Most will know the proverb but their knowledge of ado is often
restricted to a particular lexical neighbourhood without realising that it
is in fact strongly and prohibitively limited to it in this way. It is not
common to give much thought to words in combinations and modes of their
combination and realise that some, such as auspices, aback, standstill, ado,
may not depend on how the speaker would like to use them and what they
choose to say but on what the language dictates to users, that is the way
how they must be used. This does not mean that there is much liberty in the
use of other words either but these limitations are not immediately obvious
as in this case: here, words are in their usage severely restricted to one
or few more combinations only. These monocollocable words (as they are
termed here), to be found, probably, in all languages, are an obstacle in
understanding a foreign language, while, on the other hand, textbooks and
dictionaries never really give the user much warning that there is a
difficulty related to them if these should be used correctly.
German constructional phrasemes and their Russian counterparts
Authors: Dobrovol’skij Dmitrij
Published: April 2020

In this article I examine a group of semi-fixed German
expressions that are irregular with regard to the relationship between form
and meaning, namely constructional phrasemes with the deictic elements
her ‘hither’ and hin ‘thither’
[vor sich her + V] and [vor sich hin +
V]. These constructions pose considerable difficulties not only for the
description of their semantics, but also for translation into other
languages. Languages such as Russian, English and French do not have exact
equivalents of the German deictic elements hin and
her. In cases where the German deictic elements
her and hin are constituents of
relatively fixed and irregular constructions, their meaning fits even less
well their standard definition. Using corpus examples, I propose a means of
describing these constructional phrasemes in a German-Russian
dictionary.
Computational extraction of formulaic sequences from corpora
Authors: Wahl Alexander , Gries Stefan Th.
Published: April 2020

We describe a new algorithm for the extraction of formulaic
language from corpora. Entitled MERGE (Multi-word Expressions from the
Recursive Grouping of Elements), it iteratively combines adjacent bigrams
into progressively longer sequences based on lexical association strengths.
We then provide empirical evidence for this approach via two case studies.
First, we compare the performance of MERGE to that of another algorithm by
examining the outputs of the approaches compared with manually annotated
formulaic sequences from the spoken component of the British National
Corpus. Second, we employ two child language corpora to examine whether
MERGE can predict the formulas that the children learn based on caregiver
input. Ultimately, we show that MERGE indeed performs well, offering a
powerful approach for the extraction of formulas.
Collecting collocations from general and specialised corpora
Authors: L'Homme Marie-Claude , Azoulay Daphnée
Published: April 2020

Collocations are increasingly taken into account in general and
specialised repositories and methodologies to collect them are heavily based
on corpora. However, lexicographers and terminologists use different kinds
of corpora in which combinations are likely to behave according to specific
rules and/or patterns. This contribution presents a comparative analysis of
the collocational behaviour of 15 lexical items found in a general language
corpus and a specialised corpus on the theme of the environment. We
automatically extracted large sets of collocates (three lists of 50
collocates) for each lexical item and from each corpus and analyse different
facets of collocational behaviour: polysemy of lexical items,
characteristics of collocates (overlap, rank and semantic classes of
collocates, etc.). Our aim is to draw the attention of terminologists and
lexicographers to some specific factors affecting the behaviour of
collocations in specialized and general corpora.
Too big to fail but big enough to pay for their
mistakes
Authors: Stefanowitsch Anatol , Flach Susanne
Published: April 2020

In this paper, we illustrate the usefulness of the family of
methods collectively known as Collostructional Analysis for phraseological
research. Investigating two patterns, [too ADJ
to V] and [ADJ enough to V], we show
how a technique originally developed for the investigation of words and
constructions can be fruitfully applied to issues pertinent to phraseology,
such as the co-existence of compositional and idiomatic semantics and the
analysis of semantically complementary patterns more generally. To this end,
we use the three conventional methods (Simple, Distinctive and Co-varying
Collexeme Analyses) and propose a novel extension (Distinctive Co-varying
Collexeme Analysis) particularly suitable for the investigation of
complementary patterns. We show that collostructional analysis is suitable
for confirming hypotheses derived from qualitative analyses, as well as
uncovering subtle differences that are otherwise inaccessible for
non-empirical research.
Mobilizing student compliance
Authors: Stevanovic Melisa
Published: April 2020

Drawing on video-recorded violin lessons as data, the
article describes the violin teacher’s use of Finnish second-person
declarative and interrogative directives in mobilizing student compliance.
The data show that the declarative directives are regularly used when (1)
the student is already engaged in the task at hand and (2) the nominated
actions concern the basics of violin playing. The paper argues that these
directives are thus not only about mobilizing recipient action locally but
also about establishing normatively-desired behavior more generally. The
interrogative directives, then again, are typically used when (1) there has
been a momentary shortcoming in the student’s prior behavior and (2) the
nominated action is a one-time accomplishment facilitating the smooth
unfolding of the instructional encounter.
Doing more than expected
Authors: Zinken Jörg , Rossi Giovanni , Reddy Vasudevi
Published: April 2020

In informal interaction, speakers rarely thank a person
who has complied with a request. Examining data from British English,
German, Italian, Polish, and Telugu, we ask when speakers
do thank after compliance. The results show that
thanking treats the other’s assistance as going beyond what could be taken
for granted in the circumstances. Coupled with the rareness of thanking
after requests, this suggests that cooperation is to a great extent governed
by expectations of helpfulness, which can be long-standing, or built over
the course of a particular interaction. The higher frequency of thanking in
some languages (such as English or Italian) suggests that cultures differ in
the importance they place on recognizing the other’s agency in doing as
requested.
Noncanonical regulation of phosphatidylserine metabolism by a Sec14-like protein and a lipid kinase
Authors: Wang Yaxi , Yuan Peihua , Grabon Aby , Tripathi Ashutosh , Lee Dongju , Rodriguez Martin , Lönnfors Max , Eisenberg-Bord Michal , Wang Zehua , Man Lam Sin , Schuldiner Maya , Bankaitis Vytas A.
Published: April 2020

The yeast phosphatidylserine (PtdSer) decarboxylase Psd2 is proposed to engage in a membrane contact site (MCS) for PtdSer decarboxylation to phosphatidylethanolamine (PtdEtn). This proposed MCS harbors Psd2, the Sec14-like phosphatidylinositol transfer protein (PITP) Sfh4, the Stt4 phosphatidylinositol (PtdIns) 4-OH kinase, the Scs2 tether, and an uncharacterized protein. We report that, of these components, only Sfh4 and Stt4 regulate Psd2 activity in vivo. They do so via distinct mechanisms. Sfh4 operates via a mechanism for which its PtdIns-transfer activity is dispensable but requires an Sfh4-Psd2 physical interaction. The other requires Stt4-mediated production of PtdIns-4-phosphate (PtdIns4P), where Stt4 (along with the Sac1 PtdIns4P phosphatase and endoplasmic reticulum–plasma membrane tethers) indirectly modulate Psd2 activity via a PtdIns4P homeostatic mechanism that influences PtdSer accessibility to Psd2. These results identify an example in which the biological function of a Sec14-like PITP is cleanly uncoupled from its canonical in vitro PtdIns-transfer activity and challenge popular functional assumptions regarding lipid-transfer protein involvements in MCS function.
Non-singular Kerr-NUT-de Sitter spacetimes
Authors: Lewandowski Jerzy , Ossowski Maciej
Published: April 2020

We study Killing horizons and their neighbourhoods in the Kerr–NUT–(anti-)de Sitter and the accelerated Kerr–NUT–(anti-)de Sitter spacetimes. The geometries of the horizons have an irremovable singularity at one of the poles, unless the parameters characterising the spacetimes satisfy the constraint we derive and solve in the current paper. In the Kerr-NUT-de Sitter case, the constraint relates the cosmological constant of spacetime and the horizon area, leaving 3 parameters free. In the accelerated case the acceleration becomes a 4th parameter that allows the cosmological constant to take arbitrary value, independently of the area. We find that the neighbourhoods of the non-singular horizons are non-singular too, at least in the non-extremal case. Finally, we compare the embedded horizons with previously unembedded horizons provided by the local theory of type D Killing horizons to the second order.
Weak gravitational field effects on large-scale optical interferometric Bell tests
Authors: Rivera-Tapia M , Delgado A , Rubilar G
Published: April 2020

The technological refinement of experimental techniques has recently allowed the generation of two-photon polarization-entangled states at low Earth orbit, which has been subsequently applied to quantum communications. This achievement paves the way to study the interplay between general relativity and quantum mechanics in new setups. Here, we study the generation of two-photon energy-time entangled states via large scale Franson and Hugged interferometric arrays in the presence of a weak gravitational field. We show that for certain configurations of the arrays, an entangled state emerges as a consequence of the gravitational time delay. We also show that the aforementioned arrays generate entanglement and violate the Clauser–Horne–Shymony–Holt inequality under suitable conditions even in the presence of frequency dispersion.
Ar+-sputtered Ge (001) surface nanostructuring at target temperature above the recrystallization threshold
Authors: Chowdhury Debasree , Ghose Debabrata
Published: April 2020

Nanoscale pattern formation on Ge (001) surface by 500 eV Ar+ bombardment has been studied for a wide range of ion incidence angles at a temperature of 300° C. In the angular regime 0° to 65°, a fourfold symmetric topography forms which shows a remarkable transition into highly regular one-dimensional asymmetric pattern at grazing incidences, known as perpendicular mode ripples. The four-fold symmetric patterns are found to retain their symmetry under the concurrent substrate rotation during sputtering, while the ripples show degeneration into hole structure with a weak fourfold symmetric pattern. The dynamics of the observed patterns has also been investigated in a wide range of ion fluence from 1 × 1017 to 1 × 10 20 ions cm−2. The square topographies are found to be determined by Ehrlich–Schwoebel barrier induced diffusion bias driven growth process, whereas, the ripple formation implies the role of incidence ion beam direction.
Thermo-electro-mechanical behavior of dielectric elastomer actuators: experimental investigations, modeling and simulation
Authors: Kleo Mario , Förster-Zügel Florentine , Schlaak Helmut F , Wallmersperger Thomas
Published: April 2020

Dielectric Elastomer Actuators (DEAs) are elastic parallel plate capacitors consisting of polymers as dielectric layer and compliant electrodes’. In dynamic applications with high frequencies DEAs heat up. In this work the heating is studied by experimental investigations as well as by modeling of the visco-elastic behavior of the polymer and the specific electric resistance of the electrode and of the polymer. The experimental investigations have also been performed, in order to obtain parameters for the material model. A partially coupled thermo-electro-mechanical material model is presented and used for the numerical simulations. The experimental and numerical results for the time-dependent thermal behavior show an excellent qualitative correlation. This confirms the quality of the developed multi-field model.
Twisting waves increase the visibility of nonlinear behaviour
Authors: Richard Grace , Lay Holly S , Giovannini Daniel , Cochran Sandy , Spalding Gabriel C , Lavery Martin P J
Published: April 2020

Nonlinear behaviour for acoustic systems is readily measured at high acoustic pressures in gasses or bulk materials. However, at low acoustic pressures nonlinear effects are not commonly observed. We find that by phase structuring acoustic beams, one observes evidence of nonlinear behaviour at an acoustic pressure of 66.78 dB lower than non-structured beams in room temperature air. A bespoke 28-element ultrasonic phased array antenna was developed to generate short pulses that carry orbital angular momentum and are propagated over a short air channel. When sampling small areas of the wavefront, we observed a distinctive change in the frequency components near phase singularities. At these phase singularities the local propagation path is screwed, resulting in the collection signals from pulses travelling along different paths across the aperture of a microphone. The usually negligible frequency chirping that arises from nonlinear behaviour in air interfere at these singularity points and produce a distinctive distortion of the acoustic pulse. Simple physical movement in the system or super-sonic wave speeds do not yield similar results. Such distortions in measured frequency response near phase singularities could lead to errors for SONAR or acoustic communication systems, where received signals are integrated over a finite-area detector. With further development this behaviour could potentially lead to accurate measurement techniques for determining a material’s nonlinear properties at lower acoustic pressure.
Broadband nonreciprocal linear acoustics through a non-local active metamaterial
Authors: Sasmal Aritra , Geib Nathan , Popa Bogdan-Ioan , Grosh Karl
Published: April 2020

The ability to create linear systems that manifest broadband nonreciprocal wave propagation would provide for exquisite control over acoustic signals for electronic filtering in communication and noise control. Acoustic nonreciprocity has predominately been achieved by approaches that introduce nonlinear interaction, mean-flow biasing, smart skins, and spatio-temporal parametric modulation into the system. Each approach suffers from at least one of the following drawbacks: the introduction of modulation tones, narrow band filtering, and the interruption of mean flow in fluid acoustics. We now show that an acoustic media that is non-local and active provides a new means to break reciprocity in a linear fashion without these deleterious effects. We realize this media using a distributed network of interlaced subwavelength sensor–actuator pairs with unidirectional signal transport. We exploit this new design space to create a stable metamaterial with non-even dispersion relations and electronically tunable nonreciprocal behavior over a broad range of frequencies.
Supervised learning of time-independent Hamiltonians for gate design
Authors: Innocenti Luca , Banchi Leonardo , Ferraro Alessandro , Bose Sougato , Paternostro Mauro
Published: April 2020

We present a general framework to tackle the problem of finding time-independent dynamics generating target unitary evolutions. We show that this problem is equivalently stated as a set of conditions over the spectrum of the time-independent gate generator, thus translating the task into an inverse eigenvalue problem. We illustrate our methodology by identifying suitable time-independent generators implementing Toffoli and Fredkin gates without the need for ancillae or effective evolutions. We show how the same conditions can be used to solve the problem numerically, via supervised learning techniques. In turn, this allows us to solve problems that are not amenable, in general, to direct analytical solution, providing at the same time a high degree of flexibility over the types of gate-design problems that can be approached. As a significant example, we find generators for the Toffoli gate using only diagonal pairwise interactions, which are easier to implement in some experimental architectures. To showcase the flexibility of the supervised learning approach, we give an example of a non-trivial four-qubit gate that is implementable using only diagonal, pairwise interactions.
A general formulation of time-optimal quantum control and optimality of singular protocols
Authors: Wakamura Hiroaki , Koike Tatsuhiko
Published: April 2020

We present a general theoretical framework for finding the time-optimal unitary evolution of the quantum systems when the Hamiltonian is subject to arbitrary constraints. Quantum brachistochrone (QB) is such a framework based on the variational principle, whose drawback is that it only deals with equality constraints. While inequality constraints can be reduced to equality ones in some situations, they usually cannot, especially when a drift field, an uncontrollable part, is present in the Hamiltonian. We first develop a framework based on Pontryagin’s maximum principle (MP) in order to deal with inequality constraints as well. The new framework contains QB as a special case, and their detailed correspondence is given. Second, we address the problem of singular controls, which satisfy MP trivially so as to cause a trouble in determining the optimal protocol. To overcome this difficulty, we derive an additional necessary condition for a singular protocol to be optimal by applying the generalized Legendre–Clebsch condition. Third, we discuss general relations among the drift, the singular controls, and the inequality constraints. Finally, we demonstrate how our framework and results work in some examples. We also discuss the physical meaning of singular controls.
Effect of annealing temperature on interfacial and electrical performance of Au–Pt–Ti/HfAlO/InAlAs metal–oxide–semiconductor capacitor
Authors: Guan He , Jiang Cheng-Yu , Wang Shao-Xi
Published: April 2020

HfAlO/InAlAs metal–oxide–semiconductor capacitor (MOS capacitor) is considered as the most popular candidate of the isolated gate of InAs/AlSb high electron mobility transistor (HEMT). In order to improve the performance of the HfAlO/InAlAs MOS-capacitor, samples are annealed at different temperatures for investigating the HfAlO/InAlAs interfacial characyeristics and the device’s electrical characteristics. We find that as annealing temperature increases from 280 °C to 480 °C, the surface roughness on the oxide layer is improved. A maximum equivalent dielectric constant of 8.47, a minimum equivalent oxide thickness of 5.53 nm, and a small threshold voltage of –1.05 V are detected when being annealed at 380 °C; furthermore, a low interfacial state density is yielded at 380 °C, and this can effectively reduce the device leakage current density to a significantly low value of 1 × 10−7 A/cm2 at 3-V bias voltage. Therefore, we hold that 380 °C is the best compromised annealing temperature to ensure that the device performance is improved effectively. This study provides a reliable conceptual basis for preparing and applying HfAlO/InAlAs MOS-capacitor as the isolated gate on InAs/AlSb HEMT devices.