bluuebunny/crossref_metadata_2025 huggingface dataset:
An in situ electrical transport measurement system under ultra-high vacuum
Authors: Cui Wenqiang , Zheng Cheng , Zhang Liguo , Kang Zhixin , Li Luxin , Cai Xinqiang , Zhao Dapeng , Hu Xiaopeng , Chen Xi , Wang Yilin , Wang Lili , Wang Yayu , Ma Xucun , Xue Qi-Kun
Published: June 2020

Low-dimensional materials exhibit exotic properties and have attracted widespread attention. However, many low-dimensional materials are highly sensitive to air, making it challenging to investigate their intrinsic properties with ex situ measurements. To overcome such challenges, here, we developed a system combined with sample growth, electrode deposition, and in situ electrical transport measurement under ultra-high vacuum condition. The in situ deposition of electrodes enables desired ohmic electrical contacts between the probes and samples, which allows continuous temperature dependent resistance (R–T) measurements. Combined with a scanning tunneling microscope, surface morphology, electronic structure, and electrical transport properties of the same sample can be systematically investigated. We demonstrate the performance of this in situ electrical transport measurement system with three-unit-cell thick FeSe films grown on Nb-doped SrTiO3(001) substrates, where a low-noise R–T curve with a zero-resistance superconducting transition temperature of ∼30 K is observed.
Electric field dependent polarization switching of tetramethylammonium bromotrichloroferrate(III) ferroelectric plastic crystals
Authors: Walker Julian , Scherrer Simon , Løndal Nora Statle , Grande Tor , Einarsrud Mari-Ann
Published: June 2020

Tetramethylammonium bromotrichloroferrate(III) ([N(CH3)4][FeBrCl3]) is a plastic crystal ferroelectric with small dielectric constant <20 and piezoelectric coefficient as high as 110 pC/N. Here, super-coercive hysteresis and dielectric properties under direct current (DC) bias fields up to 260 and 120 kV/cm, respectively, were studied to shed light on the polarization switching [N(CH3)4][FeBrCl3] and the related family of plastic crystal and supramolecular ferroelectrics. [N(CH3)4][FeBrCl3] exhibited peak-to-peak strains of 0.1% and saturated ferroelastic switching at fields of 170 kV/cm. Above 170 kV/cm, rates of field increase were too fast for domain switching, resulting in reduced strain rates during the switching cycle. Leakage currents had larger contributions at higher field amplitudes. This was also reflected in the switching behavior at higher frequencies, 100 Hz, in which hysteresis was asymmetric and switching incomplete. The dielectric constant and loss exhibited a butterfly-like shape during application of DC bias electric fields indicative of domain switching, but showed a small dielectric tunability of 0.038 and no signs of dielectric stiffening, with the relative permittivity from 16.9 to 17.3 at fields from 0 to 120 kV/cm. The present findings provide insight into the domain switching kinetics and dielectric properties of [N(CH3)4][FeBrCl3] that will assist with further development of plastic crystal ferroelectrics.
Remarkable thermal rectification in pristine and symmetric monolayer graphene enabled by asymmetric thermal contact
Authors: Jiang Pengfei , Hu Shiqian , Ouyang Yulou , Ren Weijun , Yu Cuiqian , Zhang Zhongwei , Chen Jie
Published: June 2020

Thermal rectification is a nonreciprocal thermal transport phenomenon, which typically takes place in asymmetric structures or hetero-junctions. In this work, we propose a new route to achieve remarkable thermal rectification even in pristine single-layer graphene without asymmetry by engineering the thermal contacts at the two ends. When setting a fixed long thermal contact at one end and varying the length of thermal contact at the other end, our molecular dynamics simulations demonstrate that notable thermal rectification efficiency can be achieved with very short thermal contact, which vanishes in the limit of long thermal contact. Such a strategy of asymmetric thermal contact can provide a significant enhancement of thermal rectification efficiency, achieving around 920% thermal rectification in the short sample with a length of 200 nm and around 110% thermal rectification in the micrometer scale sample. Phonon participation ratio analysis reveals that the strong localization of low-frequency acoustic phonons is induced by the short thermal contact in the backward direction, leading to a significant temperature jump at the short thermal contact in the backward direction and thus the thermal rectification in pristine single-layer graphene. Our study provides a new path to achieve notable thermal rectification even in the symmetric structures by engineering the thermal contact.
A novel approach to ligand-exchange rates applied to lithium-ion battery and sodium-ion battery electrolytes
Authors: Åvall Gustav , Johansson Patrik
Published: June 2020

A novel approach based on analyzing the forces and velocities of solvents and anions to compute ligand-exchange rates is here presented and applied to lithium-ion battery (LIB) and sodium-ion battery (SIB) electrolytes. By using ab initio molecular dynamics generated data, we find the ligand-exchange rates to increase as functions of electrolyte salt concentration and to be higher in SIB electrolytes as compared to LIB electrolytes. This indicates both that Na+ transport will be more non-vehicular in nature and have improved kinetics vs Li+, and that increasing the salt concentration is beneficial. The systems studied were basically the first cation solvation shells of Li/NaPF6 in propylene carbonate and acetonitrile using three solvent to salt ratios. Overall, the solvation shells are solvent rich at low salt concentrations, and as functions of concentration, the solvents are replaced by anions. As the SIB electrolytes display higher cation coordination and solvation numbers, we also expect an earlier onset of highly concentrated electrolyte behavior for SIB than LIB electrolytes. These observations should all have an impact on the design of electrolytes for optimal bulk properties, but also be useful with respect to interfacial dynamics.
Molecular dynamics calculations of collision-induced absorption in a gas mixture of neon and krypton
Authors: Fakhardji Wissam , Szabó Péter , El-Kader M. S. A. , Gustafsson Magnus
Published: June 2020

We continue the development of the in-house molecular dynamics software package SpaCIAL and test it for the computation of the collision-induced absorption coefficients for a neon (Ne) and krypton (Kr) gas mixture. An apodization procedure for the dipole autocorrelation function is implemented and tested. We also carry out a statistical study of the convergence rate with respect to ensemble size. The resulting absorption coefficients show a good accordance with quantum mechanical results. Comparison with laboratory measurements shows agreement within 10%–20% at T = 295 K. At T = 480 K, a larger difference of 40%–80% is observed, which can presumably be explained by experimental uncertainties. For the study, an empirical (Barker, Fisher, and Watts) interaction-potential [Mol. Phys. 21, 657 (1971)] for Ne–Kr has been developed. Ab initio {coupled cluster with singles and doubles (triples) [CCSD(T)]} potentials for Ne–Ne, Kr–Kr, and Ne–Kr have been computed, as well as the CCSD(T) interaction-induced Ne–Kr dipole moment curve.
Cantilever-based ferroelectret energy harvesting
Authors: Ben Dali O. , Pondrom P. , Sessler G. M. , Zhukov S. , von Seggern H. , Zhang X. , Kupnik M.
Published: June 2020

We present a vibrational energy harvester with fluorinated ethylene propylene (FEP)-ferroelectrets working in d31 mode. The ferroelectret film consists of two FEP films, fused together to form a parallel tunnel structure with well-defined air gaps. Its dynamic piezoelectric g31 coefficient is 0.7 V m N−1. The energy-harvesting device is an air-spaced cantilever arrangement that was produced by the additive manufacturing technique. The device was tested by exposing it to sinusoidal vibrations with an acceleration a, generated by a shaker. The measurement shows a resonance at about 35 Hz and a normalized output power of 320 μW for a seismic mass of 4.5 g at an acceleration of 0.1 g (g is the gravity of the earth). This demonstrates a significant improvement of air-spaced vibrational energy harvesting with ferroelectrets and greatly exceeds previous performance data for polymer cantilever devices.
Evaluation of polarization characteristics in metal/ferroelectric/semiconductor capacitors and ferroelectric field-effect transistors
Authors: Toprasertpong Kasidit , Tahara Kento , Takenaka Mitsuru , Takagi Shinichi
Published: June 2020

In this study, we propose a measurement technique for evaluating ferroelectric polarization characteristics in ferroelectric field-effect transistors (FeFETs). Different from standard metal/ferroelectric/metal capacitors, the depletion and inversion phenomena in semiconductor substrates have to be carefully taken into account when evaluating the ferroelectric properties using fast voltage sweep as input. The non-equilibrium deep depletion is found to be the limiting factor for the accurate evaluation of ferroelectric properties in metal/ferroelectric/semiconductor capacitors. By connecting the source, the drain, and the substrate of the FeFET together during the polarization measurement, the deep depletion can be suppressed and the ferroelectricity of the ferroelectric gate can be accurately evaluated. The present technique is a powerful method for capturing the polarization states in FeFETs, enabling new approaches for device characterization and fundamental study, and overcomes the limitation found in the conventional polarization measurement on two-terminal metal/ferroelectric/semiconductor capacitors.
Effect of magnesium oxide adhesion layer on resonance behavior of plasmonic nanostructures
Authors: Sadri-Moshkenani Parinaz , Khan Mohammad Wahiduzzaman , Shafiqul Islam Md. , Montoya Eric , Krivorotov Ilya , Bagherzadeh Nader , Boyraz Ozdal
Published: June 2020

The magnesium oxide (MgO) adhesion layer is proposed to avoid adverse effects of lossy metallic adhesion layers in thin film plasmonic nanostructures. Such adverse effects can be in the form of resonance broadening and a decrease in the resonance magnitude. We fabricate and test the quality of MgO adhesion layers and determine its optical properties through ellipsometry measurements. We also provide the plasmonic response of various plasmonic nanostructures (nanohole array, nanodisk array, dimer nanohole array, and bowtie slot antenna array) with a MgO adhesion layer and conventional adhesion layers including titanium (Ti), chromium (Cr), tantalum (Ta), and indium tin oxide (ITO). Our results show that unlike conventional adhesives, MgO has almost no adverse effect on the plasmonic resonance of the designed nanostructures.
Using principal component analysis for neural network high-dimensional potential energy surface
Authors: Casier Bastien , Carniato Stéphane , Miteva Tsveta , Capron Nathalie , Sisourat Nicolas
Published: June 2020

Potential energy surfaces (PESs) play a central role in our understanding of chemical reactions. Despite the impressive development of efficient electronic structure methods and codes, such computations still remain a difficult task for the majority of relevant systems. In this context, artificial neural networks (NNs) are promising candidates to construct the PES for a wide range of systems. However, the choice of suitable molecular descriptors remains a bottleneck for these algorithms. In this work, we show that a principal component analysis (PCA) is a powerful tool to prepare an optimal set of descriptors and to build an efficient NN: this protocol leads to a substantial improvement of the NNs in learning and predicting a PES. Furthermore, the PCA provides a means to reduce the size of the input space (i.e., number of descriptors) without losing accuracy. As an example, we applied this novel approach to the computation of the high-dimensional PES describing the keto–enol tautomerism reaction occurring in the acetone molecule.
Probing the intermolecular coupled vibrations in a water cluster with inelastic electron tunneling spectroscopy
Authors: Guo Jing , Cao Duanyun , Chen Ji , Bian Ke , Xu Li-Mei , Wang En-Ge , Jiang Ying
Published: June 2020

The hydrogen-bonding networks of water have strong intra- and intermolecular vibrational coupling which influences the energy dissipation and proton transfer in water. Disentangling and quantitative characterization of different coupling effects in water at a single-molecular level still remains a great challenge. Using tip-enhanced inelastic electron tunneling spectroscopy (IETS) based on low-temperature scanning tunneling microscopy, we report the direct quantitative assessment of the intermolecular coupling constants of the OH-stretch vibrational bands of an isolated water tetramer adsorbed on a Au(111)-supported NaCl(001) bilayer film. This is achieved by distinguishing various coupled modes of the H-bonded O–H stretching vibrations through tip-height dependent IET spectra. In contrast, such vibrational coupling is negligible in the half-deuterated water tetramer owing to the large energy mismatch between the OH and OD stretching modes. Not only do these findings advance our understanding on the effects of local environment on the intermolecular vibrational coupling in water, but also open up a new route for vibrational spectroscopic studies of extended H-bonded network at the single-molecular level.
Intrinsic role of ↑↑↓↓-type magnetic structure on magnetoelectric coupling in Y2NiMnO6
Authors: Xin Chao , Song Bingqian , Sun Zhixin , Hu Zhongxiang , Yuan Boshi , Li Hui , Jin Guangyong , Pan Feng
Published: June 2020

Structure-property correlations are a major challenge in the investigation of magnetoelectric multiferroic materials. We have systematically investigated the intrinsic role of ↑↑↓↓-type order in magnetoelectric coupling in Y2NiMnO6. The calculated results reveal that the ferromagnetic (FM) order is the magnetic structure of the ground state and the total energy of ↑↑↓↓-type order is close to that of the FM order. The electric polarization is calculated to be 0.78 μC/cm2 along the crystallographic b-axis for UNi = UMn = 3 eV. In addition to the exchange-striction mechanism, a more noticeable contribution from redistribution of polarized charge is found in our study. Magnetic hysteresis loops show the ferromagnetism in Y2NiMnO6, which can be explained by magnetic field-induced spin flop transition from the E-type to FM order. Our DFT + U theoretical investigations also proposed a switching adiabatic path of magnetoelectric coupling, in which the 180° reverse of electric polarization is driven by rotation of spins.
Shape morphology of dipolar domains in planar and spherical monolayers
Authors: Barakat J. M. , Squires T. M.
Published: June 2020

We present a continuum theory for predicting the equilibrium shape and size of dipolar domains formed during liquid–liquid phase coexistence in planar and spherical monolayers. Our main objective is to assess the impact of the monolayer surface curvature on domain morphology. Following previous investigators, we base our analysis around minimizing the free energy, with contributions from line tension and electrostatic dipolar repulsions. Assuming a monodisperse system of circularly symmetric domains, we calculate self-energies and interaction energies for planar and spherical monolayers and determine the equilibrium domain size from the energy minima. We subsequently evaluate the stability of the circularly symmetric domain shapes to an arbitrary, circumferential distortion of the perimeter via a linear stability analysis. We find that the surface curvature generally promotes the formation of smaller, circularly symmetric domains instead of larger, elongated domains. We rationalize these results by examining the effect of the curvature on the intra- and inter-domain dipolar repulsions. We then present a phase diagram of domain shape morphologies, parameterized in terms of the domain area fraction and the monolayer curvature. For typical domain dimensions of 1–30 µm, our theoretical results are relevant to monolayers (and possibly also bilayers) in liquid–liquid phase coexistence with radii of curvature of 1–100 µm.
Local structure study on magnetostrictive material Tb1−xDyxFe2
Authors: Chang Tieyan , Zhou Chao , Chang Kaige , Wang Bin , Shi Qian , Chen Kaiyun , Chen Yu-Sheng , Ren Yang , Yang Sen
Published: June 2020

Tb1−xDyxFe2 system has attracted more research interest due to the large magnetostrictive effect. The crystal structures and physical properties have been well studied, but research studies on their local structures are still rare. In this work, the local structure of Tb1−xDyxFe2 samples was studied using the pair distribution function and x-ray absorption spectroscopy techniques. The results demonstrate that the system owns the same local crystal symmetry with its average structure in the ferromagnetic phase, and the crystal lattice of the system is more ordered with increasing Dy content, indicating that the Dy-rich tetragonal phase is more stable than the Tb-rich rhombohedral phase. The different roles of metallic bonds in affecting the crystal lattice are presented. The weak Fe1–Fe2 bonds influenced by the local environment such as local stress from randomly distributed nanodomains could originate the anomalies in the lattice, resulting in the more ordered and stable Dy-rich phase than the Tb-rich phase.
An elementary photo-thermoelectric transistor: Experimental demonstration
Authors: Rave-Osorio L. C. , Alvarez-Quintana J.
Published: June 2020

Viable power supply methods capable of replacing the need for batteries are a key design factor for realization of emerging technologies and platforms based on self-sustainable standalone electronics. Hence, alternate possibilities should arise by developing semiconductor devices with an inherent energy source, i.e., a device that simultaneously exhibits energy-converting as well as amplifying-modulating properties. In the present Letter, we report a proof-of-concept photo-thermoelectric modulator. Thereby, an optical signal is reproduced by the thermoelectric voltage generated by modulating, with a light beam, the free carrier concentration of a photoconductive PbS film that is under a temperature gradient. Experimental results unveil that photo-generated electrons affect more electrical conductivity than thermal conductivity, giving rise to a drastic change in thermoelectric power. Consequently, it induces significant changes in the thermoelectric figure of merit of the device, and thus, signal modulation is mainly awarded to photo-generated electrons rather than thermal effects. Therefore, the device developed here establishes the basis for the development of an elementary batteryless photo-thermoelectric transistor and opens alternative avenues for self-powered devices that are driven by temperature gradients via a photo-thermoelectric effect.
An experimental study for characterization of size-dependence in microstructures via electrostatic pull-in instability technique
Authors: Abazari Amir Musa , Fotouhi Mohamad , Tavakkoli Hadi , Rezazadeh Ghader
Published: June 2020

This paper experimentally investigates the size-dependent effective Young's modulus Eeff of aluminum (Al) clamped-clamped microbeams using the electrostatic pull-in instability technique. This study presents an experimental characterization of the so-called “length scale parameter” in couple stress theory and surface elasticity. Eeff is retrieved from the measured pull-in voltage, of the clamped-clamped beams with different dimensions, via an electromechanically coupled equation. Measurement results show a strong size dependence of Eeff for the Al beams in small sizes. The Young's modulus increases monotonously as the beams become thinner. The experimental observations are consistent with the published modeling results of the size effects, in which couple stress theory and surface elasticity theory are taken into consideration. The presented experimental method has substantial advantages such as precise adjustable magnitude of the non-contacting force and a lower cost over the other approaches used for characterization of micro-/nanoelectromechanical systems. This simple and reproducible method can be extended for characterization of various materials with different sizes and boundary conditions.
Spin Seebeck effect detection by harmonic analysis
Authors: Romanque-Albornoz Cristian , Gonzalez-Fuentes Claudio , Orellana Christian , Garcia Carlos
Published: June 2020

We present an alternative measurement technique for the longitudinal spin Seebeck effect (SSE), based on harmonic analysis of the signal measured in the Y3Fe5O12/Pt bilayer. In our experimental setup, we use a harmonic magnetic field and a static thermal gradient in the longitudinal configuration to induce a square-wave SSE signal. By using a phase-sensitive detection technique (lock-in), we can reduce the impact of electrical noise, which improves sensitivity and, through harmonic analysis of the measured signal, decouples in real time the SSE signal from other thermoelectric effects.
Epitaxial L1-FeNi films with high degree of order and large uniaxial magnetic anisotropy fabricated by denitriding FeNiN films
Authors: Ito Keita , Hayashida Masahiro , Masuda Hiroto , Nishio Takahiro , Goto Sho , Kura Hiroaki , Koganezawa Tomoyuki , Mizuguchi Masaki , Shimada Yusuke , Konno Toyohiko J. , Yanagihara Hideto , Takanashi Koki
Published: June 2020

L10-orderd FeNi alloy films with a high degree of order (S) and a large uniaxial magnetic anisotropy energy (Ku) were realized by denitriding FeNiN films. FeNiN films with the a-axis perpendicular to the film plane were epitaxially grown on SrTiO3 (001) substrates by molecular beam epitaxy by changing the growth temperatures (TS) to 200, 250, and 350 °C. The a-axis oriented epitaxial L10-FeNi films were fabricated by annealing the FeNiN films in a H2 gas atmosphere at 300 °C. S and Ku of the denitrided L10-FeNi films were characterized by anomalous x-ray diffraction using synchrotron radiation and magnetic torque measurements, respectively. A high S of 0.87 and a Ku of 5.9 × 105 J/m3 were realized in the L10-FeNi film with a TS of 350 °C. This high S value exceeds the values reported on L10-FeNi to date, but the Ku value was comparable to those of c-axis oriented L10-FeNi films with S ∼ 0.5 grown by alternate monoatomic deposition of Fe and Ni layers. A possible origin for the suppressed macroscopic Ku in a-axis oriented L10-FeNi films is discussed, and denitriding FeNiN is a promising method for the fabrication of L10-FeNi with a high S and a large Ku.
Experimental investigations on density bunching and its power influence in a relativistic backward-wave oscillator with low-magnetic-field operation
Authors: Wang Huida , Xiao Renzhen , Chen Changhua , Shi Yanchao
Published: June 2020

In a relativistic backward-wave oscillator operating at a low magnetic field, forward intense relativistic electron beams propagate with large transverse velocities and form a non-uniform beam-density distribution. This paper first investigates periodical density bunching by bombarding targets with electron beams in a relativistic drift tube. Then, the dependence of the density-bunching phase on interaction efficiency is studied experimentally for the first time with a C-band relativistic backward-wave oscillator. The results show a reduction in microwave power of over 40%, arising from a mismatch between the density-bunching phase and the standing-wave field in the resonant reflector, which is in reasonable agreement with particle-in-cell simulation results.
First stages of plasticity in three-point bent Au nanowires detected by in situ Laue microdiffraction
Authors: Ren Z. , Cornelius T. W. , Leclere C. , Davydok A. , Micha J.-S. , Robach O. , Richter G. , Thomas O.
Published: June 2020

The first stages of plasticity in three-point bent Au nanowires are investigated by in situ three-point bending tests in combination with Laue micro-diffraction. To separate the elastic and plastic deformation, loading–unloading cycles were performed with increasing load in each consecutive cycle. The storage of the first four geometrically necessary dislocations of [011¯](111) slip system is observed in the vicinity of both clamping points, which might be attributed to the local rotations induced by the rigid Si support. At later stages of the deformation, additional slip systems are activated either by the torsion of the nanowire or by unintentional indentation from the AFM tip. The cyclic loading–unloading approach combined with Laue microdiffraction thus allows to study the onset of plasticity in defect-scarce nanostructures deformed by bending, offering additional possibilities in studying the dislocation nucleation process in bent nano-objects, which are essential for future applications, e.g., in flexible electronics and nano-electromechanical systems.
Review of Scientific Instruments New Products
Authors: Mandelis Andreas
Published: June 2020

In order to supplement manufacturers’ information, this department will welcome the submission by our readers of brief communications reporting measurements on the physical properties of materials, which supersede earlier data or suggest new research applications.
What is the answer to the challenge of multimorbidity in New Zealand?
Authors: Askerud Anna , Jaye Chrystal , McKinlay Eileen , Doolan-Noble Fiona
Published: June 2020

ABSTRACT
The increasing prevalence of multimorbidity, a growing ageing population and lack of success in addressing the negative effect of socioeconomic and cultural determinants of health are major challenges for New Zealand’s primary care sector. Self-management support strategies, personalised care planning, integrated care and shared health records have all been proposed as mechanisms to address these challenges. The organisation of the health system, however, remains largely unchanged, with limited accommodation and few funding concessions made for the requirements of these different approaches and tools. As a result, the primary care system is no longer a good match for the population it serves. With one in four New Zealanders reporting multimorbidity, and people aged >65 years predicted to double in number by 2050, this article argues that over the next decade, New Zealand requires a health system focused on incorporating self-management support, personalised and integrated care and shared health records. This will require further educating of not only health professionals, but also patients in the purpose behind these approaches. In addition, it will mean transitioning to a primary care system more suited to the needs of people with long-term conditions. The key gain from a radical redesign will be a more equitable health system focused on a broader range of health needs.
Petroglyphs of Victoria
Authors: Bednarik Robert G.
Published: June 2020

Victorian rock art in its Australian context is considered, focusing on petroglyphs and the natural markings mistaken for rock art. Nearly all known Victorian petroglyphs occur in limestone caves, with only three minor sites currently reported to be above ground. These occurrences are described briefly, and an explanation of their distribution in the context of Tasmanian and mainland rock art suites is attempted.
Captive breeding of two rare non-migratory galaxiids (Teleostei: Galaxiidae) for species conservation
Authors: Stoessel Daniel J. , Raadik Tarmo A. , Nicol Michael D. , Fairbrother Peter S. , Campbell-Beschorner Ruby
Published: June 2020

Devising effective techniques for breeding and rearing rare non-migratory galaxiids is urgently required for conservation purposes where few animals exist in the wild for translocation or reintroduction. The development of such protocols is particularly pertinent in light of recent intense widespread bushfires and long-term drought in southeastern Australia, which have increased the likelihood of the need for captive maintenance to protect and recover remnant species. In this study, we promoted reproductive maturation via manipulation of day length and temperature, and produced viable offspring from two small, endemic freshwater galaxiids, Galaxias fuscus (Mack 1936) and Galaxias longifundus (Raadik 2014) using in vitro propagation techniques. Propagation trials resulted in 425 oocytes being stripped from four ripe G. fuscus females, and 1527 oocytes from three ripe G. longifundus females. Of these, 342 (80.5%) G. fuscus and 968 (63.4%) G. longifundus eggs hatched into larvae. Newly hatched G. fuscus and G. longifundus larvae were transparent, and 8.4–9.7 mm (mean 9.0 mm TL) and 7.1–8.9 mm (mean 8.3 mm TL) consecutively. Absorption of the yolk sac by G. fuscus larvae (1.5–2.0 mm diameter) was complete 6–7 days after hatching, and for G. longifundus (1.0–1.4 mm diameter) 12–13 days after hatching. One-month-old G. fuscus measured ~16 mm and two-month-old larvae ~22 mm, and one-month-old G. longifundus ~11 mm. Methods and techniques employed may aid broader galaxiid conservation efforts.
Strategies for aligning syntactic roles and case marking with
semantic properties
Authors: Romagno Domenica
Published: June 2020

In the present paper, we show that: (1) the
accusative of respect, a case marker for inalienable possession in
ancient Greek, represents a strategy for aligning syntactic roles
and case marking with animacy; (2) this hypothesis can consistently
account for a series of issues that remained unsettled; (3) the
semantic properties of the predicate involved in the accusative of
respect are fundamental to defining its function and specifically
govern its distribution. Our analysis comprises Greek literary
texts, from Homer to the fifth century B.C.
Parallel syncretism in early Indo-European
Authors: Rapaport Steve
Published: June 2020

Oblique-oblique case mergers are now known to be
exceedingly rare outside Indo-European, yet very common within it
(Baerman, Brown, and
Corbett, 2001, 2005). Explanations of these mergers given after 2001
now need to include factors that are, individually or collectively,
unique to Indo-European. In this paper, a set of such Indo-European
specific factors is proposed, mainly phonological and prosodic, and
its implications explored, particularly for the Germanic, Italic and
Celtic families. We begin with Proto-Indo-European accent and ablaut
morphology and PIE’s existing syncretism of the ablative case.
Timelines and examples in Proto-Germanic help flesh out the
explanation.
Dative possessor in ditransitive Spanish predication, in
diachronic perspective
Authors: Ortiz Ciscomani Rosa María
Published: June 2020

This paper analyses the diachronic behavior (12th
to 20th centuries) of the ditransitive predications, with Direct
Object (DO) and Indirect Object (IO), coded by Noun Phrases in
Spanish. The analysis accounts for the properties of those
participants, possessor and possessed respectively, and the verbs in
the constructions. The analytic approach assumes that transitivity
is a scalar phenomenon, without distinction between actantial and
non-actantial dative. The possessive dative is an
IO that refers to the possessor of the DO, while the ditransitive
construction is an extension of the prototypical ditransitive. Our
claim is that the construction i) gives relevance to the possessor
over the possessed, and ii) shows that diachronically the DO has
lexically diversified from concrete to non-concrete and animate
entities, especially from the 16th century onwards.
The actualization of new voice patterns in Romance
Authors: Cennamo Michela
Published: June 2020

This article discusses some aspects of the
reorganization of voice distinctions in the transition from Latin to
Romance, namely the grammaticalization of activity (do /
make) and change of state (become) verbs as
markers of the passive voice, and the reanalysis of the reflexive
morpheme se as a voice modulator, focussing on patterns of
invariance (i.e., persistence) of Latin inheritance and principled
differences (i.e., divergence) in the type and extent of variation
and further developments in this area of Romance morphosyntax.
Synchrony, diachrony, and indexicality
Authors: Andersen Henning
Published: June 2020

This paper is about the current disconnect
between synchronic and diachronic linguistics and the need for
historical linguists to take the lead in addressing the big issues
in morphology: how agglutination develops into fusion and symbolism,
how these techniques are maintained through time, how they devolve
into agglutinative or isolating patterns. The formation and
reanalysis of allomorphy are central to these developments. The
paper advocates a theory of the morphological sign by which
allomorphs form subsidiary paradigms and the individual allomorph is
both symbol and index: it stands for its exponendum and points to
features of its environment. This articulate conception facilitates
the detailed analysis and interpretation both of synchronic patterns
and of the gradual typological transformations of inflectional
systems.
Remotivating inflectional classes
Authors: Gaeta Livio
Published: June 2020

In Titsch, a Walser German dialect spoken in the
Aosta Valley, a remodeling of the old strong/weak verb classes found
in the rest of the Germanic languages has taken place, whereby verbs
belonging to the strong class turn out to display both strong and
weak past participles. This outcome results from the reuse or
exaptation of the original morphological differentiation based on a
purely lexically-governed distribution which has been remotivated by
associating the morphological features with specific constructional
schemas resulting from several processes of grammaticalization.
Old French si, grammaticalisation, and the
interconnectedness of change
Authors: Wolfe Sam
Published: June 2020

The particle SI is ubiquitous across the early
French textual record, yet receives no uniform analysis, with
numerous competing and often contradictory claims in the literature
about its distribution and formal status. This study draws on a
novel diachronic corpus analysis to put forward an original analysis
of SI, under which it is not the homogeneous entity often assumed
but rather an adverbial which grammaticalises as a topic-continuity
marker and, later, two forms of V2-related expletive. SI loses its
previously specific temporal and discourse-pragmatic meaning, shows
a widening of distribution and occupies an increasingly high
position within the left periphery. In these respects it is shown to
instantiate a classic form of upwards grammaticalisation
pathway.
The rise of the analytic Perfect aspect in the West Iranian
languages
Authors: Bubenik Vit , Ziamajidi Leila
Published: June 2020

This paper focuses on the long-term
grammaticalization of tense/aspect systems in the West Iranian
languages, beginning with Old Iranian (Section 1). In Middle Persian (Section 2) the Aorist and the
reduplicative Perfect of Old Persian were replaced by a new system
of analytic constructions. The fundamental mechanism in the rise of
the innovative Preterit (perfective) and Perfect categories was the
process of grammaticalization, reducing the auxiliary ‘be’ into
suffixes of the innovative Preterit. In Early New Persian (Section 3) an unambiguous
Perfect was recreated by attaching personal suffixes to the Perfect
stem. In the second part of the paper (Section 4) we turn to the elaboration of the
evidential (‘non-witnessed’) subsystem in New Persian through
grammaticalization and possible Turkic influence. A typological
parallel in the southernmost Slavic languages (Section 5) is provided.
On the grammaticalization of the -(v)ši-
resultative in North Slavic
Authors: Danylenko Andrii
Published: June 2020

It is commonly accepted that the
-(v)ši- resultatives in North Slavic are a
product of the areal diffusion of a similar resultative formation in
-vęs- (< *-ṷes-) from
Baltic. The author argues that the anterior grammaticalization of
the -(v)ši- resultative in North Slavic has been
largely an internally motivated process. The analysis is premised on
the distinction of spoken vs. written discourse which preconditions
the parallel use of finite and non-finite predication, including the
resultative structures, in the history and dialects of North Slavic.
The author argues that language contact was but one of several
factors influencing the convergent tendencies in the use of
resultatives in the Circum-Baltic zone and well beyond.
The rich get richer
Authors: Sundquist John D.
Published: June 2020

This study investigates five common light verbs
in an Old Swedish corpus of texts from 1225–1526, focusing on the
increasing frequency with which light verbs combine with an
ever-widening range of NP-objects. Tools of statistical analysis
from network science and ecology are used to track changes in
frequency and diversity. Results indicate that light verbs are a
small, closed class of verbs with unique historical properties that
set them apart from more lexically-specific verbs. The way in which
they grow more frequent and diverse is typical of the
“rich-get-richer” phenomenon of preferential attachment in studies
of dynamic network growth.
Contact-induced change and the phonemicization of the vowel /ɑ/
in Quảng Nam Vietnamese
Authors: Pham Andrea Hoa
Published: June 2020

This paper is an account of the emergence of the
low, back, unrounded vowel /ɑ/ in the Quảng Nam dialect spoken in
south central Vietnam. This vowel is not seen in any other dialects.
The paper provides evidence for a trace of this vowel in two
subdialects of Hà Tĩnh province, north central Vietnam (Phạm, 1997, 2014, 2016), and claims that the Quảng Nam /ɑ/
originated from Hà Tĩnh dialects through migration. It was brought
to Quảng Nam by early settlers mainly during the 15th to 18th
centuries, where the vowel was further internally restructured
through various linguistic processes. The Quảng Nam /ɑ/, therefore,
originates from two sources: dialect contact and internal
restructuring.
On the non-triviality of unit transformations
Authors: Bisabr Yousef
Published: June 2020

There are some theoretical arguments about possible variations of fundamental constants with cosmic time. We review the fact that all conversion factors depend on these quantities and consider how their variations may affect transformations of units. We deal with the relevance of the issue to the cosmological constant problem.
Compact, magnetically actuated, additively manufactured pumps for liquids and gases
Authors: Taylor Anthony P , Izquierdo Reyes Javier , Velásquez-García Luis Fernando
Published: June 2020

We report the proof-of-concept demonstration of novel, valve-less, and magnetically actuated miniature (∼1 cm3) positive displacement pumps for liquids and gases—both single-material-printed pumps with embedded sintered magnets and the first monolithic, fully 3D-printed, multi-material magnetic pumps in the literature; a valve-less design greatly simplifies the pump’s operation and consumes less power compared to designs with active valves, and is less prone to clogging than designs with passive valves. The miniature diaphragm pumps are fabricated using 150μm-thick to 225μm-thick layers via fused filament fabrication; the structural parts are printed in pure Nylon 12, while the magnet that makes possible the actuation of the pump chamber is either monolithically printed in Nylon 12 embedded with NdFeB micro-particles or press-fit into the pump after single-material printing of the enclosing piston. The fabrication of the pumps employs a novel multi-material-compatible 3D printing process flow that monolithically creates all features with less than 13μm of in-plane misalignment. Pump fabrication takes below 75 min to complete and costs under $3.89 in materials. The devices are driven by a rotating magnet and can deliver liquid flow rates as large as 7.88 ml min−1at 198 Hz for sintered magnet pumps (N35 grade) and 1.68 ml min−1at 204 Hz for the devices with monolithically 3D-printed magnets (∼N4 grade); the results surpass state-of-the-art, 3D-printed miniature liquid pumps. Actuation of a pump in excess of 14.4 million cycles shows no evidence of degradation, e.g. leaks. A pump with sintered magnet (N48 grade) was characterized as a vacuum pump using air as working fluid, achieving an ultimate pressure of 540 Torr in a 0.61 ml pumping volume and up to 9.3 ml min−1flow rate at 230 Hz actuation; the results compare well with miniature, commercial, non-3D-printed vacuum pumps.
Fabrication of a polycrystalline SiGe- and Ge-on-insulator by Ge condensation of amorphous SiGe on a SiO2/Si substrate
Authors: Lin Guangyang , Liang Dongxue , Huang Zhiwei , Yu Chunyu , Cui Peng , Zhang Jie , Wang Jianyuan , Xu Jianfang , Chen Songyan , Li Cheng , Zeng Yuping
Published: June 2020

In this work, the Ge condensation effect of amorphous SiGe on a SiO2/Si substrate is systematically investigated. As Ge condensation proceeds, the Ge content gradually enriches from an initial 0.24–1.0 with improving crystal quality. The enlargement of the grain size results in gradual roughening of the surface roughness. As the Ge content reaches 0.36, a high hole mobility of ∼211 cm2 · V−1 · s−1 is achieved with a hole concentration of ∼3.7 × 1015 cm−3. As the Ge content further accumulates, the grain number increases resulting in a higher hole concentration. The film mobility gradually deteriorates probably due to the following factors: strong impurity scattering at high hole concentration, increase of grain boundaries, decrease of SiGe thickness, and increase of surface roughness. A polycrystalline Ge-on-insulator with a hole concentration of ∼5.1 × 1018 cm−3 and mobility of ∼15 cm2 · V−1 · s−1 is ultimately fabricated. The investigation provides a promising method to fabricate a high hole mobility SiGe-on-insulator platform from low-cost amorphous SiGe.
Reconstructing complex system dynamics from time series: a method comparison
Authors: Hassanibesheli Forough , Boers Niklas , Kurths Jürgen
Published: June 2020

Modeling complex systems with large numbers of degrees of freedom has become a grand challenge over the past decades. In many situations, only a few variables are actually observed in terms of measured time series, while the majority of variables—which potentially interact with the observed ones—remain hidden. A typical approach is then to focus on the comparably few observed, macroscopic variables, assuming that they determine the key dynamics of the system, while the remaining ones are represented by noise. This naturally leads to an approximate, inverse modeling of such systems in terms of stochastic differential equations (SDEs), with great potential for applications from biology to finance and Earth system dynamics. A well-known approach to retrieve such SDEs from small sets of observed time series is to reconstruct the drift and diffusion terms of a Langevin equation from the data-derived Kramers–Moyal (KM) coefficients. For systems where interactions between the observed and the unobserved variables are crucial, the Mori–Zwanzig formalism (MZ) allows to derive generalized Langevin equations that contain non-Markovian terms representing these interactions. In a similar spirit, the empirical model reduction (EMR) approach has more recently been introduced. In this work we attempt to reconstruct the dynamical equations of motion of both synthetical and real-world processes, by comparing these three approaches in terms of their capability to reconstruct the dynamics and statistics of the underlying systems. Through rigorous investigation of several synthetical and real-world systems, we confirm that the performance of the three methods strongly depends on the intrinsic dynamics of the system at hand. For instance, statistical properties of systems exhibiting weak history-dependence but strong state-dependence of the noise forcing, can be approximated better by the KM method than by the MZ and EMR approaches. In such situations, the KM method is of a considerable advantage since it can directly approximate the state-dependent noise. However, limitations of the KM approximation arise in cases where non-Markovian effects are crucial in the dynamics of the system. In these situations, our numerical results indicate that methods that take into account interactions between observed and unobserved variables in terms of non-Markovian closure terms (i.e., the MZ and EMR approaches), perform comparatively better.
Covariance matrix entanglement criterion for an arbitrary set of operators
Authors: Tripathi Vinay , Radhakrishnan Chandrashekar , Byrnes Tim
Published: June 2020

A criterion for entanglement detection based on covariance matrices for an arbitrary set of observables is formulated. The method generalizes the covariance matrix entanglement criterion by Simon (2000 Phys. Rev. Lett.
84 2726) to a more general set of operators using the positive partial transpose test for the covariance matrix. The relation is found by starting from the generalized uncertainty relation for multiple operators, and taking the partial transpose on the bipartition. The method is highly efficient and versatile in the sense that the set of measurement operators can be freely chosen, and there is no constraint on the commutation relations. The main restriction on the chosen set of measurement operators is that the correlators and expectation values of the partially transposed observable operators can be evaluated. The method is particularly suited for systems with higher dimensionality since the computations do not scale with the dimension of the Hilbert space—rather they scale with the number of chosen observables. We illustrate the approach by examining the entanglement between two spin ensembles, and show that it detects entanglement in a basis independent way.
Variation tolerance for high-speed negative capacitance FinFET SRAM bit cell
Authors: Qian Yaqian , Qiao Shushan , Yang Rongqiang
Published: June 2020

Negative capacitance FinFET (NC-FinFET) has a promising developmental prospect due to its superior performance in SS < 60 mV/dec (subthreshold swing), especially in SRAM. Noise margin is an important metric to evaluate the performance for SRAM, together with static leakage, read speed, etc. In this paper, we study the effects of the variation of ferroelectric material (thickness, polarization), FinFET critical physical parameters (fin number, channel length) and some ambient factors (working temperature, supply voltage) on the performance of NC-FinFET SRAM within the reasonable fluctuation tolerance range. The SRAM bit cell is analyzed with a basic 6T structure. The impact of fin number and channel length for NC-FinFET SRAM is different from that of conventional FinFETs. Additionally, the ferroelectric material and some other factors are assessed in detail.
An early-warning indicator for Amazon droughts exclusively based on tropical Atlantic sea surface temperatures
Authors: Ciemer Catrin , Rehm Lars , Kurths Jürgen , Donner Reik V , Winkelmann Ricarda , Boers Niklas
Published: June 2020

Droughts in tropical South America have an imminent and severe impact on the Amazon rainforest and affect the livelihoods of millions of people. Extremely dry conditions in Amazonia have been previously linked to sea surface temperature (SST) anomalies in the adjacent tropical oceans. Although the sources and impacts of such droughts have been widely studied, establishing reliable multi-year lead statistical forecasts of their occurrence is still an ongoing challenge. Here, we further investigate the relationship between SST and rainfall anomalies using a complex network approach. We identify four ocean regions which exhibit the strongest overall SST correlations with central Amazon rainfall, including two particularly prominent regions in the northern and southern tropical Atlantic. Based on the time-dependent correlation between SST anomalies in these two regions alone, we establish a new early-warning method for droughts in the central Amazon basin and demonstrate its robustness in hindcasting past major drought events with lead-times up to 18 months.