bluuebunny/crossref_metadata_2025 huggingface dataset:
Self-consistent modeling of the electron–cyclotron maser interaction in lossy structures based on a full-wave Green's function approach
Authors: Chelis I. , Peponis D. , Zelkas A.
Published: March 2022

We develop a new self-consistent model for simulation of the electron–cyclotron maser interaction in cylindrical structures, where expansion of the fields in transverse eigenmodes cannot be directly applied. Instead of solving the nonhomogeneous equation for the fields as a differential equation, a different approach is followed. First, the Green's function for elementary azimuthal and radial RF current sources is analytically derived by expanding the fields in longitudinal modes. Then, the total generated field is calculated by representing the perturbed electron beam as a sum of elementary RF current sources along the axis with amplitude coefficients that are found from the kinematic quantities of the electrons. The self-consistent stationary solution is found by solving the equations of motion along with the field equation in an iterative procedure. The model is useful for the full-wave simulation of lossy structures, which are frequently found in gyro-devices, such as ceramic-loaded interaction circuits of gyro-traveling-wave tubes and beam tunnels of gyrotron oscillators.
Global and local modal characteristics of supersonic open cavity flows
Authors: Doshi Parshwanath S. , Ranjan Rajesh , Gaitonde Datta V.
Published: March 2022

Flows past cavities at high-speeds have become increasingly important in applications such as flame-holding and propulsion unstart control. Recently maturated linear techniques have helped discern the underlying mechanisms in the subsonic and low supersonic speed regime (M∞<1.4). Here, we combine these linear methods with fully non-linear two- and three-dimensional simulations to assimilate the significant changes observed when the Mach number is increased further to the 1.4≤M∞≤3 range. The resolvent method is first employed to analyze cavity-shear layer coupled oscillations and modal characteristics, which are found to differ in key respects from those reported at lower Mach numbers. At higher speeds, more 2D coupled modes are obtained with the dominant modes containing secondary waves displaying elaborate patterns. The role of the shear layer on the cavity dynamics is then examined with local spatial stability analyses. In addition to the well-known Kelvin–Helmholtz instability encountered in the subsonic and transonic regimes, forward-propagating (k+) supersonic shear layer instabilities are detected at higher speeds. These are associated with Mach wave reflections between the shear layer and the cavity floor and may introduce higher order coupled modes. Furthermore, 3D modal analysis indicates a shift toward the dominance of 3D modes compared to 2D modes; although consistent with compressible free shear layer observations, 2D cavity modes remain significant to higher convective Mach number. When the Reynolds number is increased, resolvent-based mode shapes and frequencies continue to compare favorably with Dynamic Mode Decomposition of large-eddy simulations because of inviscid instability dominance.
Tuning the giant magnetocaloric effect in MnCoGe alloy with external pressure
Authors: Sharma V. K. , Garg Nandini , Manekar Meghmalhar
Published: March 2022

We report the effect of hydrostatic pressure on the magnetocaloric effect across the magneto-structural transition in an off-stoichiometric Mn34.5Co33.1Ge32.4 alloy. A very large isothermal entropy change of 38.95 J kg−1 K−1 is observed at nearly 303 K for a magnetic field excursion of 7 T at ambient pressure. The temperature of the peak entropy change and, thus, the working temperature range of the alloy drastically decrease by about 45 K with the application of a moderate hydrostatic pressure of 297 MPa. This shift is explained by correlating the results of x-ray diffraction measurements performed under high pressure for studying the structural aspect of the transition. Our results highlight the potential of the Mn–Co–Ge alloy system for multi-caloric applications in which the temperature change can be achieved by more than one external stimulus. The present work may also lead to future experiments, which study the response of multi-calorics driven by many external stimuli within the same experimental environment.
A two- and three-dimensional mesoscopic method for an updated non-homogeneous model of Newtonian and non-Newtonian nanofluids
Authors: Kefayati Gholamreza
Published: March 2022

A mesoscopic method based on a lattice Boltzmann method (LBM) for simulation of Newtonian and non-Newtonian nanofluids has been introduced. This investigation is a continuation of our recent study [G. H. R. Kefayati and A. Bassom, “A lattice Boltzmann method for single and two phase models of nanofluids: Newtonian and non-Newtonian nanofluids,” Phys. Fluids 33, 102008 (2021)], which proposed a two-dimensional LBM for a non-homogeneous model of nanofluids with Brownian diffusion and thermophoresis. Here, this model is improved by considering thermodynamic consistency, deposition rate, nanoparticle thermal dispersion, and hydrodynamic interactions around the nanoparticles, which are evaluated and reported in some thermodynamic and experimental observations. The proposed method is also developed for three-dimensional cases, applying all the above-mentioned elements. The revised macroscopic governing equations of mass (one for the carrier fluid and the other for the nanoparticles), momentum, and energy by considering the newly mentioned elements are presented, and then the proposed LBM, which has the ability to recover equations, is introduced while the derivations and proofs are provided. Different elements of the present code are validated with previous studies and demonstrated good agreement. To apply and evaluate the model in a case study, natural convection of Newtonian, shear-thinning, and viscoplastic nanofluids in a side-heated two-dimensional square enclosure and in a cubic cavity are investigated. The results for various volume fractions of nanofluids and Grashof numbers are shown in the formats of isotherms, streamlines, nanoparticle distributions, and local and average Nusselt numbers on the hot wall. In addition, the yielded/unyielded regions for viscoplastic nanofluids are defined and depicted.
Photodissociation dynamics of N3+
Authors: Patra Sarbani , San Vicente Veliz Juan Carlos , Koner Debasish , Bieske Evan J. , Meuwly Markus
Published: March 2022

The photodissociation dynamics of N3+ excited from its (linear) 3Σg−/(bent) 3A″ ground to the first excited singlet and triplet states is investigated. Three-dimensional potential energy surfaces for the 1A′, 1A″, and 3A′ electronic states, correlating with the 1Δg and 3Πu states in linear geometry, for N3+ are constructed using high-level electronic structure calculations and represented as reproducing kernels. The reference ab initio energies are calculated at the MRCI+Q/aug-cc-pVTZ level of theory. For following the photodissociation dynamics in the excited states, rotational and vibrational distributions P(v′) and P(j′) for the N2 product are determined from vertically excited ground state distributions. Due to the different shapes of the ground state 3A″ potential energy surface and the excited states, appreciable angular momentum j′ ∼ 60 is generated in diatomic fragments. The lifetimes in the excited states extend to at least 50 ps. Notably, results from sampling initial conditions from a thermal ensemble and from the Wigner distribution of the ground state wavefunction are comparable.
The atomistic modeling of light-harvesting complexes from the physical models to the computational protocol
Authors: Cignoni Edoardo , Slama Vladislav , Cupellini Lorenzo , Mennucci Benedetta
Published: March 2022

The function of light-harvesting complexes is determined by a complex network of dynamic interactions among all the different components: the aggregate of pigments, the protein, and the surrounding environment. Complete and reliable predictions on these types of composite systems can be only achieved with an atomistic description. In the last few decades, there have been important advances in the atomistic modeling of light-harvesting complexes. These advances have involved both the completeness of the physical models and the accuracy and effectiveness of the computational protocols. In this Perspective, we present an overview of the main theoretical and computational breakthroughs attained so far in the field, with particular focus on the important role played by the protein and its dynamics. We then discuss the open problems in their accurate modeling that still need to be addressed. To illustrate an effective computational workflow for the modeling of light harvesting complexes, we take as an example the plant antenna complex CP29 and its H111N mutant.
Hybridisation, pollen–pistil interactions and hybrid seed set among
Authors: Pauldasan Abraham , Vipin Pulpayil , Durai Arumugam , Nicodemus Abel
Published: March 2022

Context Casuarina trees are extensively planted in the tropics for wood production and environmental services. The breeding program’s current focus is on developing hybrids that combine the specific characteristics of different species and are suitable for various planting environments and end uses. Aim Breeding programs aim to develop interspecific hybrids possessing desirable combinations of species-specific characters of Casuarina for increasing plantation productivity. Methods Controlled-pollination studies were conducted involving C. equisetifolia, C. junghuhniana and C. cristata to determine the possibility of hybridisation among them and to evaluate the hybridisation success rate in different cross-combinations. The pollen-tube growth in the pistil was studied to understand the role of pollen–pistil interactions in hybridisation success. Key result Fourteen cross-combinations of the three species resulted in 2–57% fruit set and 75.1–93.8% seed set. C. equisetifolia and C. junghuhniana hybridised reciprocally, whereas C. cristata hybridised with other species only as pollen parent. The larger flower size of C. cristata acted as a barrier preventing hybridisation with species having smaller-sized flowers. Variation in seed germination was large (3.6–91.3%), highest for C. junghuhniana and lowest for C. equisetifolia mothers. Fertilisation occurred 45 days after pollination in C. equisetifolia and C. junghuhniana and after 50 days in C. cristata. The ovary was immature at pollination and pollen tubes showed discontinuous growth in the pistil marked by periods of arrest for the ovules to develop. The stigma showed 3–5.7 pollen tubes, and invariably a single tube entered the ovary. The absence of major pre-fertilisation barriers but varying levels of hybridisation success indicates post-zygotic selection through embryo abortion. Conclusion Increasing the parental combinations of interspecific crosses where fruit set is limiting and pollinating more flowers per cross where germination is low may enhance hybridisation success. Implications The cross compatibility among different species of Casuarina provides scope to produce site and end-use specific hybrids to meet the commercial and livelihood needs.
Investigating the effectiveness of virtual treatment via telephone triage in a New Zealand general practice
Authors: Ure Andrew
Published: March 2022

Introduction Telemedicine, including telephone triage, is increasingly being used in New Zealand general practices. Telephone triage involves diverting requests for same-day healthcare to a phone system where presenting complaints are explored only sufficiently to identify the most appropriate management pathway. Aim To assess the rates of repeat triage among general practice patients treated virtually via phone and compare these with outcomes for patients who were dealt with in person. Method 6 weeks of clinical telephone triage data were collected for Gore Medical Centre. Comparisons were made for patients treated virtually or in person, for whether complaints were a respiratory issue or not, and for whether their triage represented incomplete resolution of a previously triaged health complaint. To do this, patient notes for the 7 days prior to the phone triage were reviewed for medical consultations related to the same condition. Results Over 6 weeks, 455 telephone triages took place at the Gore Medical Centre: 133 triage phone calls resulted in 132 (29%) patients being treated virtually. Over the 6 study weeks, 19 virtually treated triage patients phoned again for further care of the same problem within 7 days (14%) while 23 patients (7%) who had been triaged to in person assessment also sought further care within 7 days. This difference was statistically significant (P < 0.05). There was no statistical difference in re-triage rates between Māori and non-Māori. Young age was a significant predictor for likelihood of re-triage. Discussion Virtual treatment via telephone triage at Gore Medical Centre resulted in a statistically increased likelihood of re-triage within 7 days compared with in person treatment. This raises questions about the efficacy of virtual treatment via telemedicine compared with in person treatment after triage.
ΔNp63-Senataxin circuit controls keratinocyte differentiation by promoting the transcriptional termination of epidermal genes
Authors: Gatti Veronica , Fierro Claudia , Compagnone Mirco , La Banca Veronica , Mauriello Alessandro , Montanaro Manuela , Scalera Stefano , De Nicola Francesca , Candi Eleonora , Ricci Francesco , Fania Luca , Melino Gerry , Peschiaroli Angelo
Published: March 2022

Significance

ΔNp63 is a master regulator of skin homeostasis since it finely controls keratinocyte differentiation and proliferation. Here, we provide cellular and molecular evidence demonstrating the functional role of a ΔNp63 interactor, the R-loop–resolving enzyme Senataxin (SETX), in fine-tuning keratinocyte differentiation. We found that SETX physically binds the p63 DNA–binding motif present in two early epidermal differentiation genes, Keratin 1 (KRT1) and ZNF750, facilitating R-loop removal over their 3′ ends and thus allowing efficient transcriptional termination and gene expression. These molecular events translate into the inability of SETX-depleted keratinocytes to undergo the correct epidermal differentiation program. Remarkably, SETX is dysregulated in cutaneous squamous cell carcinoma, suggesting its potential involvement in the pathogenesis of skin disorders.
Warming temperatures drive at least half of the magnitude of long-term trait changes in European birds
Authors: McLean Nina , Kruuk Loeske E. B. , van der Jeugd Henk P. , Leech David , van Turnhout Chris A. M. , van de Pol Martijn
Published: March 2022

Significance

Climate change is impacting wild populations, but its relative importance compared to other causes of change is still unclear. Many studies assume that changes in traits primarily reflect effects of climate change, but this assumption is rarely tested. We show that in European birds global warming was likely the single most important contributor to temporal trends in laying date, body condition, and offspring number. However, nontemperature factors were also important and acted in the same direction, implying that attributing temporal trends solely to rising temperatures overestimates the impact of climate warming. Differences among species in the amount of trait change were predominantly determined by these nontemperature effects, suggesting that species differences are not due to variation in sensitivity to temperature.
A milk-sharing economy allows placental mammals to overcome their metabolic limits
Authors: Cerrito Paola , Spear Jeffrey K.
Published: March 2022

Significance

Here, we demonstrate that a naturally evolving behavior (allonursing) has greater effect on reproductive power (mass per unit of time) and output (litter mass at birth) than does artificial selection (domestication). Additionally, we demonstrate the importance of resource optimization afforded by sociality (rather than resource abundance per se) in shaping a species’ life history profile and its ability to overcome its own physiological constraints.
Molecular mechanism underlying the TLR4 antagonistic and antiseptic activities of papiliocin, an insect innate immune response molecule
Authors: Krishnan Manigandan , Choi Joonhyeok , Jang Ahjin , Choi Sungjae , Yeon Jiwon , Jang Mihee , Lee Yeongjoon , Son Kkabi , Shin Soon Young , Jeong Myeong Seon , Kim Yangmee
Published: March 2022

Significance

Similar to mammalian TLR4/MD-2, the Toll9/MD-2–like protein complex in the silkworm,Bombyx mori,acts as an innate pattern-recognition receptor that recognizes lipopolysaccharide (LPS) and induces LPS-stimulated expression of antimicrobial peptides such as cecropins. Here, we report that papiliocin, a cecropin-like insect antimicrobial peptide from the swallowtail butterfly, competitively inhibits the LPS-TLR4/MD-2 interaction by directly binding to human TLR4/MD-2. Structural elements in papiliocin, which are important in inhibiting TLR4 signaling via direct binding, are highly conserved among insect cecropins, indicating that its TLR4-antagonistic activity may be related to insect Toll9-mediated immune response against microbial infection. This study highlights the potential of papiliocin as a potent TLR4 antagonist and safe peptide antibiotic for treating gram-negative sepsis.
Failed remyelination of the nonhuman primate optic nerve leads to axon degeneration, retinal damages, and visual dysfunction
Authors: Sarrazin Nadège , Chavret-Reculon Estelle , Bachelin Corinne , Felfli Mehdi , Arab Rafik , Gilardeau Sophie , Brazhnikova Elena , Dubus Elisabeth , Yahia Cherif Lydia , Lorenceau Jean , Picaud Serge , Rosolen Serge , Moissonnier Pierre , Pouget Pierre , Baron-Van Evercooren Anne
Published: March 2022

Significance

Promotion of remyelination has become a new therapeutic avenue to prevent neuronal degeneration and promote recovery in white matter diseases, such as multiple sclerosis (MS). To date most of these strategies have been developed in short-lived rodent models of demyelination, which spontaneously repair. Well-defined nonhuman primate models closer to man would allow us to efficiently advance therapeutic approaches. Here we present a nonhuman primate model of optic nerve demyelination that recapitulates several features of MS lesions. The model leads to failed remyelination, associated with progressive axonal degeneration and visual dysfunction, thus providing the missing link to translate emerging preclinical therapies to the clinic for myelin disorders such as MS.
A mechanism for the strange metal phase in rare-earth intermetallic compounds
Authors: Wang Jiangfan , Chang Yung-Yeh , Chung Chung-Hou
Published: March 2022

Significance

The elusive strange metal phase (ground state) was observed in a variety of quantum materials, notably in
f
-electron–based rare-earth intermetallic compounds. Its emergence has remained unclear. Here, we propose a generic mechanism for this phenomenon driven by the interplay of the gapless fermionic short-ranged antiferromagnetic spin correlation and critical bosonic charge fluctuations near a Kondo breakdown quantum phase transition. It is manifested as a fluctuating Kondo-scattering–stabilized critical (gapless) fermionic spin liquid. It shows

ω
/
T

scaling in dynamical electron scattering rate, a signature of quantum criticality. Our results on quasilinear-in-temperature scattering rate and logarithmic-in-temperature divergence in specific heat coefficient as temperature vanishes were recently seen in CePd

1
−
x

Ni

x

Al.
Electronegativity and chemical hardness of elements under pressure
Authors: Dong Xiao , Oganov Artem R. , Cui Haixu , Zhou Xiang-Feng , Wang Hui-Tian
Published: March 2022

Significance

Over the years, many unusual chemical phenomena have been discovered at high pressures, yet our understanding of them is still very fragmentary. Our paper addresses this from the fundamental level by exploring the key chemical properties of atoms—electronegativity and chemical hardness—as a function of pressure. We have made an appropriate modification to the definition of Mulliken electronegativity to extend its applicability to high pressures. The change in atomic properties, which we observe, allows us to provide a unified framework explaining (and predicting) many chemical phenomena and the altered behavior of many elements under pressure.
A hypothesis concerning distinct schemes of olfactory activation evoked by perceived versus nonperceived input
Authors: Traub Roger D. , Whittington Miles A.
Published: March 2022

Significance

The authors propose that odors are consciously perceived or not, depending on whether the olfactory cortex succeeds in activating the endopiriform nucleus—a structure that, in turn, is capable of activating multiple downstream brain areas. The authors further propose that the cellular mechanisms of endopiriform nucleus activation are an attenuated form of cellular events that occur during epileptic seizure initiation. If correct, the authors’ hypothesis could help explain the mechanisms of action of certain general anesthetics.
How real has the long-anticipated fast-growing influence of American English on Kenyan English been?
Authors: Buregeya Alfred
Published: March 2022

In the 1990s, the existing literature anticipated a fast-growing influence of American English on Kenyan English in the following years.Mazrui and Mazrui (1996)even predicted a “coca-colanization” of Kenyan English. Focusing on vocabulary, the present study investigated whether the anticipated influence has occurred or not. From a sample of 75 fourth-year university students it collected self-reports of which words they used from 93 pairs of American-vs-British English counterparts. These self-reports were then compared with, among others, the frequencies of the same words in two corpora of Kenyan English which were compiled two decades apart. The study found that the respondents’ self-reports indicated a 59 percent use of British English vocabulary, against only a 28 percent use of American English vocabulary. This finding was by and large corroborated by the frequencies of the words concerned in the two corpora. Thus, the anticipated American English influence has not materialized.
Politician, activist… or hero?
Authors: Galindo-Ramírez Joaquín , Jaraíz-Arroyo Germán , Hernández-Ramírez Macarena
Published: March 2022

This article explores how narratives and their discursive elements construct the idea of rebelliousness in subjects who followed different pathways through politics and activism after the Spanish 15-M movement. Methodologically, two representative examples of narratives have been selected on the basis of interviews with participants in the movement. To study these cases, the concept of rebel narratives is proposed from the perspective of narrative as social practice. The analysis applied here is based on a dialogue between the two cases studied, as discourses in which the activity of their tellers develops in certain contexts of discourse production. Based on this analysis, it is suggested that rebelliousness, in addition to manifesting subjective affiliations, fulfils a performative function with which the subjects legitimise their chosen path and constitute themselves, motivating, in the cases presented, revisions of the past or the rhetoric characteristic of a hero.
Reading fiction with an e-book or in print
Authors: Kosch Lukas , Stocker Günther , Schwabe Annika , Boomgaarden Hajo G.
Published: March 2022

Empirical research on the differences between digital and print reading has recently increased, mainly concentrating on informational texts while disregarding literary texts. Concerning narrative fiction, the existing quantitative studies have found no or very few differences between reading printed books and e-books. In our focus group study, we amplify the perspective on digital and print book reading through a largely explorative approach. The results gained by interviewing 34 habitual readers of e-books in six groups show that e-books complement rather than replace printed books. Crucial differences can be found in the dimensions of the reading situation, genre selection, purpose of reading, as well as literary quality and status of the text. Furthermore, our results shed new light on the importance of the printed book as an individual material object, with its own specific iconicity and with notable consequences for intellectual possession, memory, and remembrance of read books and lived reading experiences.
High-speed friction stir welding in light weight battery trays for the EV industry
Authors: Patel Vivek , De Backer Jeroen , Hindsefelt Henrik , Igestrand Mattias , Azimi Saeed , Andersson Joel , Säll Jörgen
Published: March 2022

Present work aims to achieve high welding speed during friction stir welding of lightweight battery trays in the electric vehicle industry. This study reports high-speed friction stir welding (HSFSW) up to 4.0 m min−1 in AA6063-T6 alloys. The defect-free HSFSW joints are produced by adopting aggressive material mixing, i.e. higher tool rotation and plunge force. HSFSW weld cross-section reported an unusual hardness profile of ‘U’ shape instead of ‘W’ shape in conventional FSW of AA6xxx alloys. HSFSW resulted softening of weld stir zone (∼60HV) along with HAZ (∼53HV) against the base material (BM) hardness of ∼90HV. The HSFSW at 4.0 m min−1 obtained good joint strength of 71% of the BM. Microstructure evolutions across the fractured weld cross-section are discussed using EBSD analysis.
Anisotropic compact stars in Rastall–Rainbow gravity
Authors: Mota Clésio E , Santos Luis C N , da Silva Franciele M , Flores César V , da Silva Tiago J N , Menezes Débora P
Published: March 2022

In this work, we investigate anisotropic effects on the equations of state (EoS) used to describe neutron and quark stars in the framework of Rastall–Rainbow gravity. All our calculations are computed using two different EoS to describe the matter contained within the star: the MIT bag model for quark stars and the IU-FSU parameterisation for the standard hadronic matter. From the values of masses and radii obtained, we can conclude that anisotropic pressure has significant consequences on the structure of compact objects. Specifically, when anisotropy is considered within general relativity, it significantly modifies the maximum stellar mass. On the other hand, when Rastall–Rainbow gravity and anisotropy are simultaneously considered, they provide the best results for the masses and radii of some important astrophysical objects such as the low-mass x-ray binary (LMXB) NGC 6397 and the extremely massive millisecond pulsating source of radio (PSR) J0740 + 6620, for instance. Radii results inferred from the Lead Radius EXperiment (PREX-2) and the compact object in the mass-gap of GW190814 event can also be described for certain values of the Rastall–Rainbow and anisotropy parameters.
Parametric instability in the neutron star extreme matter observatory
Authors: Pan Juntao , Zhang Jue , Blair Carl , Jones Aaron W , Zhao Chunnong , Ju Li
Published: March 2022

Parametric instability (PI), induced by the interaction between the cavity optical modes and acoustic modes of a mirror, is an inherent risk in interferometric gravitational wave detectors. The instability can result in exponential growth in acoustic mode amplitude and the saturation of detectors control systems. In this paper we analyse PI in the neutron star extreme matter observatory, a proposed high optical power (4.5 MW) detector, operating at cryogenic temperatures with silicon test masses (TMs), targeting high sensitivity between 1 and 4 kHz. Our results show that with current design parameters, approximately 16 unstable modes will arise per TM with maximum parametric gain ∼10. Varying the TM radius of curvature from the nominal values could eliminate PI, however not with current manufacture or actuator capability. PI mitigation will be required to suppress all unstable modes. This analysis identifies four optical modes and 16 acoustic modes dominating PI in NEMO paves the way for the design of PI mitigation strategies.
The spectroscopic ellipsometry measurement of non-polar freestanding GaN: comparison between isotropic and anisotropic models
Authors: Wang Yakun , Xu Gengzhao , Han Sha , Chen Kebei , Zhang Chunyu , Song Wentao , Wang Jianfeng , Liu Zhenghui , Xu Ke
Published: March 2022

For anisotropic materials, the pseudo-dielectric function (DF) from isotropic model is often applied in spectroscopic ellipsometry data analysis instead of the DF from anisotropic model because of its simplicity. Whether this approximation is applicable depends on the discrepancy between the pseudo-DF and the DF, which we find to be related to the illumination configuration greatly. For the ellipsometry spectra obtained from a non-polar freestanding GaN in two configurations with the c-axis perpendicular and parallel to the incident plane respectively, both anisotropic model and isotropic model are used to compare the difference between the fitted absorption coefficient and pseudo-absorption coefficient. As a consequence, the discrepancy between the two coefficients is less than 10

%

even at the absorption edge when electric field is perpendicular to the c-axis, while the discrepancy exceeds 40

%

at the absorption edge when electric field is parallel to the c-axis. These results indicate that the approximation of using isotropic model instead of anisotropic model is reasonable in the former configuration, while it is not applicable in the latter configuration and will render an overestimation of bandgap. The above two different discrepancies could be explained by the first-order term approximation of pseudodielectric function. We further demonstrate the necessity for anisotropic model by comparing the deviations of the crystal-field splitting obtained from anisotropic and isotropic model with the theoretical value respectively.
Valley polarized transport and negative differential resistance in an irradiated

α−T3

lattice
Authors: Niu Zhi Ping , Wang Shuo Jun
Published: March 2022

In this work, we study the valley dependent current in an

α
−

T

3

lattice based device via the non-equilibrium Green’s function method. The influences of off-resonant circularly polarized light on band structures and current–voltage characteristics are investigated. In the presence of circularly polarized light, the band structures, particularly in the flat band, are distorted, and the valley degeneracy is broken, causing the current valley to be polarized. If the circularly polarized light only irradiates the right electrode, one valley is forward conducting but backward blocking, and the opposite is valid for the other valley; thus a bipolar valley diode effect is demonstrated. When the light’s handedness is reversed, the valley indexes of the currents are swapped. If the circularly polarized lights irradiate both electrodes, by reversing the light’s handedness the device can be switched between an ‘on’ state, with a 100% valley polarized current and an ‘off’ state. Interestingly, negative differential resistance is observed, becoming more pronounced as α decreases. The features reported here make the

α
−

T

3

lattice ideal for future valleytronics applications.
Tunable magnetic and magnetotransport properties in locally epitaxial La0.67Sr0.33MnO3 thin films on polycrystalline SrTiO3, by control of grain size
Authors: Dallocchio Marie , Boileau Alexis , Mercey Bernard , David Adrian , Lüders Ulrike , Froissart Sandrine , Larose Xavier , Bérini Bruno , Dumont Yves , Pautrat Alain , Prellier Wilfrid , Fouchet Arnaud
Published: March 2022

La0.67Sr0.33MnO3 (LSMO) thin films have been grown by pulsed laser deposition on SrTiO3 using combinatorial substrate epitaxy (CSE) approach, i.e. polycrystalline substrates with micrometer-size grains. The crystallographic domains size of those polycrystalline substrates can be controlled between 2 and 45 µm depending on the annealing temperature during synthesis. Each grain of the substrate acts as a single crystalline growth template promoting local epitaxy with a reproduction of the substrate grain structure in the thin film. Therefore, a fine-tuning of the substrate grain metrics and high crystalline quality of locally epitaxial LSMO film, allows to combine the advantages of polycrystalline, i.e. the presence of low field magnetoresistance (LFMR) and the possibility to use very thin films, with a pronounced magnetic shape anisotropy. For this, the magnetic and transport properties of the films are showing a strong influence with varying grain metrics of the substrate. High Curie temperatures, important values of the LFMR and anisotropy for optimized substrate grain metrics with the relative orientation of the magnetic field to the film plane underline the high quality of the films and the advantage of the CSE approach. The obtained LSMO thin films may have an interest for high-resolution low field magnetic sensors application.
Quantifying transfer learning synergies in infinite-layer and perovskite nitrides, oxides, and fluorides
Authors: Sahinovic Armin , Geisler Benjamin
Published: March 2022

We combine density functional theory simulations and active learning (AL) of element-embedding neural networks (NNs) to explore the sample efficiency for the prediction of vacancy layer formation energies and lattice parameters in ABX

n
infinite-layer (n = 2) versus perovskite (n = 3) nitrides, oxides, and fluorides in the spirit of transfer learning. Following a comprehensive data analysis from different thermodynamic, structural, and statistical perspectives, we show that NNs model these observables with high precision, using merely

∼
30
%

of the data for training and exclusively the A-, B-, and X-site element names as minimal input devoid of any physical a priori information. Element embedding autonomously arranges the chemical elements with a characteristic recurrent topology, such that their relations are consistent with human knowledge. We compare two different embedding strategies and show that these techniques render additional input such as atomic properties negligible. Simultaneously, we demonstrate that AL is largely independent of the initial training set, and exemplify its superiority over randomly composed training sets. Despite their highly distinct chemistry, the present approach successfully identifies fundamental quantum-mechanical universalities between nitrides, oxides, and fluorides that enhance the combined prediction accuracy by up to 16% with respect to three specialized NNs at equivalent numerical effort. This quantification of synergistic effects provides an impression of the transfer learning improvements one may expect for similarly complex materials. Finally, by embedding the tensor product of the B and X sites and subsequent quantitative cluster analysis, we establish from an unbiased artificial-intelligence perspective that oxides and nitrides exhibit significant parallels, whereas fluorides constitute a rather distinct materials class.
Molecular dynamics simulations of tensile mechanical properties and microstructures of Al-4.5Cu alloy: the role of temperature and strain rate
Authors: Wang Mingjie , Huang Xixi , Wu Shiping , Dai Guixin
Published: March 2022

In this paper, the deformation behavior of Al-4.5Cu alloys containing the Cu clusters under high temperature is systematically investigated by molecular dynamics. Reduced nucleation stress of dislocation is driven by increasing strain rate and temperature, which triggers the stress–strain curves of Al-4.5Cu alloy showing gradually elastic-plastic stage and elastic-plastic-viscous stage. Besides, the defect surface in Al-4.5Cu alloy do not have enough time to move along and gather due to the increase of strain rate, which make the distribution of defect surface mainly divide into three types: the plane distribution which is at 45° angle to the direction of tensile, the stratification distribution which is perpendicular to the direction of tensile and the distribution of honeycomb, respectively. The microscopic fracture morphology for Al-4.5Cu alloy are changed from pure shear fracture to microporous aggregate fracture due to three type of defect surface.
A first principles investigation of ternary and quaternary II–VI zincblende semiconductor alloys
Authors: Mannodi-Kanakkithodi Arun
Published: March 2022

One of the most common ways of tuning the stability, electronic structure, and optical behavior of semiconductors is via composition engineering. By mixing multiple isovalent elements at any cation or anion site, new compositions may be generated with markedly different properties than end-point compositions, and not always lying within a predictable trend. In this work, we explore the trends in lattice constant, electronic band gap, formation and mixing energy, and optical absorption behavior in a series of II–VI zincblende semiconductors with Cd/Zn at the cation site and S/Se/Te at the anion site, using multiple levels of density functional theory approximations. We find that while the GGA-PBE functional reproduces all trends correctly, full geometry optimization with the HSE06 functional predicts band gaps with much higher experimental accuracy. We find that all mixed S–Se and mixed Cd–Zn compounds show linear trends in band gap, rising from Se to S and Cd to Zn, respectively, whereas all Se–Te mixed compounds exhibit band gap bowing. All mixing energy curves, calculated based on decomposition to end point compositions, show inverted bowing behavior but with small positive mixing energy values <50 meV per formula unit, indicating robust stability of all solid solutions. Formation energies, calculated based on decomposition to elemental species, always show linear trends and remain sufficiently negative for all binaries, ternaries and quaternaries, whereas lattice constants show expected linear trends. We further report trends in optical absorption spectra and relationships between PBE and HSE computed properties, which reveal equations that can be used to accurately predict higher fidelity data. This work lays out systematic trends in the stability and optoelectronic characteristics of Cd–Zn–S–Se–Te alloys and enables the selection of optimal compositions for desired applications.
Increasing the structural and compositional diversity of ion-track templated 1D nanostructures through multistep etching, plastic deformation, and deposition
Authors: Hossain U H , Jantsen G , Muench F , Kunz U , Ensinger W
Published: March 2022

Ion-track etching represents a highly versatile way of introducing artificial pores with diameters down into the nm-regime into polymers, which offers considerable synthetic flexibility in template-assisted nanofabrication schemes. While the mechanistic foundations of ion-track technology are well understood, its potential for creating structurally and compositionally complex nano-architectures is far from being fully tapped. In this study, we showcase different strategies to expand the synthetic repertoire of ion-track membrane templating by creating several new 1D nanostructures, namely metal nanotubes of elliptical cross-section, funnel-shaped nanotubes optionally overcoated with titania or nickel nanospike layers, and concentrical as well as stacked metal nanotube-nanowire heterostructures. These nano-architectures are obtained solely by applying different wet-chemical deposition methods (electroless plating, electrodeposition, and chemical bath deposition) to ion-track etched polycarbonate templates, whose pore geometry is modified through plastic deformation, consecutive etching steps under differing conditions, and etching steps intermitted by spatially confined deposition, providing new motifs for nanoscale replication.
Enhancement of lateral Casimir force on a rotating particle near hyperbolic metamaterial
Authors: Wang Tong-Biao , Zhou Ying , Mu Hong-Qian , Shehzad Khurram , Zhang De-Jian , Liu Wen-Xing , Yu Tian-Bao , Liao Qing-Hua
Published: March 2022

Enhancement of weak Casimir forces is extremely important for their practical detection and subsequent applications in variety of scientific and technological fields. We study the lateral Casimir forces acting on the rotating particles with small radius of 50 nm as well as that with large radius of 500 nm near the hyperbolic metamaterial made of silicon carbide (SiC) nanowires. It is found that the lateral Casimir force acting on the small particle of 50 nm near hyperbolic metamaterial with appropriate filling fraction can be enhanced nearly four times comparing with that acting on the same particle near SiC bulk in the previous study. Such enhancement is caused by the coupling between the resonance mode excited by nanoparticle and the hyperbolic mode supported by hyperbolic metamaterial. The results obtained in this study provide an efficient method to enhance the interaction of nanoscale objects.
Fabrication of highly sensitive and uniform Ag/PS/PDMS SERS substrate and its application for in-situ detection
Authors: Xu Guangming , Shen Xilong , Zhang Lei , Tang Jie , He Chuan , Zhou Ziqiang , Xu Tian , Xu Meifeng , Jin Yonglong , Wang Chaonan
Published: March 2022

In this study, we developed a flexible and transparent silver/polystyrene/polydimethylsiloxane (Ag/PS/PDMS) substrate with both high density of hot spots and satisfactory uniformity using a cost-effective approach. Via template-guided self-assembly, PS beads were arranged regularly in nanobowls of a square array on PDMS, whose surface structure was transferred from a commercial complementary metal oxide semiconductor chip. Roughness was introduced onto the PS bead surface by nitrogen plasma treatment, followed by sputtering of Ag which generated many hot spots. Differential roughness on the PS bead surface greatly influenced the morphology of the Ag/PS/PDMS substrate. A meat-ball like surface structure was formed with a plasma etching time of 5 min, whose growth mechanism was proposed based on the scanning electron microscope analysis. The high sensitivity and desirable uniformity of the meat-ball like Ag/PS/PDMS substrate were demonstrated by using crystal violet as a Raman reporter, exhibiting an enhancement factor of 2.7 × 107 and a relative standard deviation of 5.04%. Thiram of a lower concentration than the maximum residue limit on the cucumber surface could easily be detected in situ by the proposed substrate, demonstrating its great potential for in-situ food safety analysis.
Maximising D − T fusion power by optimising the plasma composition and beam choice in JET
Authors: Van Eester D , Lerche E , Huynh P , Johnson T , Yadikin D , Štancar Ž , Aleiferis S , Frigione D , Garzotti L , Lomas P , Lowry C , Maslov M
Published: March 2022

JET has a neutral beam injection as well as a radio frequency (RF) system for bringing plasmas to fusion-relevant temperatures. The former allows D as well as T birth energies of the order of 100–120 keV while the latter has the flexibility to heat a variety of populations by adjusting the antenna frequency. In this paper it is illustrated that—when the JET plasma is heated—the power harvested from D − T fusion reactions favours operating away from the 50–50 D − T balance and that exploiting pure D beams is more beneficial than combined D and T beams as well as pure T beams. Although beam heating dominates the overall behaviour in JET—as much more beam power than wave power can be coupled to the plasma—RF heating allows efficient heating of the very core.
Development and experiment evaluation of a compact inchworm piezoelectric actuator using three-jaw type clamping mechanism
Authors: Deng Jie , Zhang Shijing , Li Yiqing , Ma Xuefeng , Gao Xiang , Xie Hui , Liu Yingxiang
Published: March 2022

A compact inchworm piezoelectric actuator using three-jaw type clamping mechanism is developed in this study. Different from the previous inchworm piezoelectric actuators constructed with guiding structures, the proposed actuator can drive an output shaft to realize linear motion without other auxiliary structures based on the automatic centering and guidance functions of the designed three-jaw type clamping mechanism, and a compact structure is obtained. The configuration of the actuator is presented to describe the operating principle in detail. Then the structures of the clamping and actuating units are designed by the assistance of finite element simulations. A prototype is fabricated and a compact structure is achieved with outer diameter of 34 mm and length of 40 mm. The experiments are performed to investigate the characteristics, a maximum speed of 155.5 μm s−1 and a thrust force of 12.3 N are achieved. The experimental results confirm that the proposed inchworm actuator can achieve a compact structure by adopting the designed three-jaw type clamping mechanisms, it has great potential in integration with precision equipment, which is conductive to apply in the fields of biological manipulation robots and aerospace devices.
Multi-scale nonlinear stress analysis of Nb3Sn superconducting accelerator magnets
Authors: Sun Eric Qiuli
Published: March 2022

A multi-scale nonlinear procedure to analyze the stress in Nb3Sn superconducting accelerator magnets is presented to address one of the most challenging obstacles currently facing the successful development of high-field superconducting magnets—the issue of stress management. The study demonstrates that gasket materials (special nonlinear materials) are capable of modeling the complex nonlinear deformation behavior of insulation layers within the Nb3Sn coil block and that Hill materials (orthotropic materials utilizing the Hill yield criterion) are suitable to enable homogenization of the filamentary regions and the resin-impregnated Nb3Sn Rutherford cables. With the whole magnet under preload, cool-down, and Lorentz forces, the nonlinear behavior of the Nb3Sn coil was simulated, in three orthongonal axes, using the combined properties of the gasket materials (insulation layers) and Hill materials (resin-impreganted cable). The procedure makes very few assumptions with regard to material properties because it incorporates actual measured stress–strain curves in the analysis. The coil was simulated to the level of detail of the insulation layers and resin-impregnated cables. The computed compressive azimuthal stresses of the cables were used to assess stress-induced performance degradation. Through submodeling, the area-weighted average axial strains of the strands were computed and employed to evaluate the strain-induced performance degradation. The overall performance degradation of the Nb3Sn coil was thus obtained, and this information was subsequently used to guide the design of the overall magnet. Besides Nb3Sn magnets, this versatile procedure can also be employed in the design of LTS, HTS, and room temperature magnets or of any structures ultilizing composite materials; specifically, it can be used to manage the stress and strain of HTS fusion magnets.
Enhanced generation of angle correlated photon-pairs in nonlinear metasurfaces
Authors: Mazzanti Andrea , Parry Matthew , Poddubny Alexander N , Della Valle Giuseppe , Neshev Dragomir N , Sukhorukov Andrey A
Published: March 2022

We reveal that strongly enhanced generation of photon pairs with narrow frequency spectra and sharp angular correlations can be realised through spontaneous parametric down-conversion in metasurfaces. This is facilitated by creating meta-gratings through nano-structuring of nonlinear films of sub-wavelength thickness to support the extended bound state in the continuum resonances, associated with ultra-high Q-factors, at the biphoton wavelengths across a wide range of emission angles. Such spectral features of photons can be beneficial for various applications, including quantum imaging. Our modelling demonstrates a pronounced enhancement, compared to unpatterned films, of the total photon-pair generation rate normalized to the pump power reaching 1.75 kHz mW−1, which is robust with respect to the angular bandwidth of the pump, supporting the feasibility of future experimental realisations.