bluuebunny/crossref_metadata_2025 huggingface dataset:
Optical and near-infrared stellar activity characterization of the early M dwarf Gl 205 with SOPHIE and SPIRou
Authors: Cortés-Zuleta P. , Boisse I. , Klein B. , Martioli E. , Cristofari P. I. , Antoniadis-Karnavas A. , Donati J.-F. , Delfosse X. , Cadieux C. , Heidari N. , Artigau É. , Bellotti S. , Bonfils X. , Carmona A. , Cook N. J. , Díaz R. F. , Doyon R. , Fouqué P. , Moutou C. , Petit P. , Vandal T. , Acuña L. , Arnold L. , Astudillo-Defru N. , Bourrier V. , Bouchy F. , Cloutier R. , Dalal S. , Deleuil M. , Demangeon O. D. S. , Dumusque X. , Forveille T. , Gomes da Silva J. , Hara N. , Hébrard G. , Hoyer S. , Hussain G. , Kiefer F. , Morin J. , Santerne A. , Santos N. C. , Segransan D. , Stalport M. , Udry S.
Published: March 2023

Context. The stellar activity of M dwarfs is the main limiting factor in the discovery and characterization of the exoplanets orbiting them, because it induces quasi-periodic radial velocity (RV) variations.

Aims. We aim to characterize the magnetic field and stellar activity of the early, moderately active M dwarf Gl 205 in the optical and near-infrared (NIR) domains.

Methods. We obtained high-precision quasi-simultaneous spectra in the optical and NIR with the SOPHIE spectrograph and SPIRou spectropolarimeter between 2019 and 2022. We computed the RVs from both instruments and the SPIRou Stokes V profiles. We used Zeeman–Doppler imaging (ZDI) to map the large-scale magnetic field over the time span of the observations. We studied the temporal behavior of optical and NIR RVs and activity indicators with the Lomb-Scargle periodogram and a quasi-periodic Gaussian process regression (GPR). In the NIR, we studied the equivalent width of Al I, Ti I, K I, Fe I, and He I. We modeled the activity-induced RV jitter using a multi-dimensional GPR with activity indicators as ancillary time series.

Results. The optical and NIR RVs show similar scatter but NIR shows a more complex temporal evolution. We observe an evolution of the magnetic field topology from a poloidal dipolar field in 2019 to a dominantly toroidal field in 2022. We measured a stellar rotation period of Prot = 34.4 ± 0.5 days in the longitudinal magnetic field. Using ZDI, we measure the amount of latitudinal differential rotation (DR) shearing the stellar surface, yielding rotation periods of Peq = 32.0 ± 1.8 days at the stellar equator and Ppol = 45.5 ± 0.3 days at the poles. We observed inconsistencies in the periodicities of the activity indicators that could be explained by these DR values. The multi-dimensional GP modeling yields an RMS of the RV residuals down to the noise level of 3 m s−1 for both instruments while using Hα and the BIS in the optical and the full width at half maximum (FWHM) in the NIR as ancillary time series.

Conclusions. The RV variations observed in Gl 205 are due to stellar activity, with a complex evolution and different expressions in the optical and NIR revealed thanks to an extensive follow-up. Spectropolarimetry remains the best technique to constrain the stellar rotation period over standard activity indicators, particularly for moderately active M dwarfs.
Mining archival data from wide-field astronomical surveys in search of near-Earth objects
Authors: Saifollahi Teymoor , Verdoes Kleijn Gijs , Williams Rees , Micheli Marco , Santana-Ros Toni , Helmich Ewout , Koschny Detlef , Conversi Luca
Published: March 2023

Context. Increasing our knowledge of the orbits and compositions of near-earth objects (NEOs) is important for a better understanding of the evolution of the Solar System and life. The detection of serendipitous NEO appearances among the millions of archived exposures from large astronomical imaging surveys can provide a contribution which is complementary to NEO surveys.

Aims. Using the ASTROWISE information system, this work aims to assess the detectability rate, the achieved recovery rate and the quality of astrometry when data mining the European Southern Observatory (ESO) archive for the OmegaCAM wide-field imager at the VLT Survey Telescope (VST).

Methods. We developed an automatic pipeline that searches for NEO appearances inside the ASTROWISE environment. Throughout the recovery process the pipeline uses several public web tools (SSOIS, NEODyS, JPL Horizons) to identify possible images that overlap with the positions of NEOs, and acquires information on the NEOs’ predicted position and other properties (e.g. magnitude, rate, and direction of motion) at the time of observations. Considering these properties, the pipeline narrows down the search to potentially detectable NEOs, searches for streak-like objects across the images, and finds a matching streak for the NEOs.

Results. We recovered 196 appearances of NEOs from a set of 968 appearances predicted to be recoverable. It includes appearances for three NEOs that were on the impact risk list at that point. These appearances occurred well before their discovery. The subsequent risk assessment using the extracted astrometry removes these NEOs from the risk list. More generally, we estimate a detectability rate of ~0.05 per NEO at a signal-to-noise ratio higher than 3 for NEOs in the OmegaCAM archive. Our automatic recovery rates are 40% and 20% for NEOs on the risk list and the full list, respectively. The achieved astrometric and photometric accuracy is on average 0.12″ and 0.1 mag.

Conclusions. These results show the high potential of the archival imaging data of the ground-based wide-field surveys as useful instruments for the search, (p)recovery, and characterization of NEOs. Highly automated approaches, as possible using ASTROWISE, make this undertaking feasible.
Photometry and spectroscopy of the Type Icn supernova 2021ckj
Authors: Nagao T. , Kuncarayakti H. , Maeda K. , Moore T. , Pastorello A. , Mattila S. , Uno K. , Smartt S. J. , Sim S. A. , Ferrari L. , Tomasella L. , Anderson J. P. , Chen T.-W. , Galbany L. , Gao H. , Gromadzki M. , Gutiérrez C. P. , Inserra C. , Kankare E. , Magnier E. A. , Müller-Bravo T. E. , Reguitti A. , Young D. R.
Published: March 2023

We present photometric and spectroscopic observations of the Type Icn supernova (SN) 2021ckj. This rare type of SNe is characterized by a rapid evolution and high peak luminosity as well as narrow lines of highly ionized carbon at early phases, implying an interaction with hydrogen- and helium-poor circumstellar matter (CSM). SN 2021ckj reached a peak brightness of ∼ − 20 mag in the optical bands, with a rise time and a time above half maximum of ∼4 and ∼10 days, respectively, in the g and cyan bands. These features are reminiscent of those of other Type Icn SNe (SNe 2019hgp, 2021csp, and 2019jc), with the photometric properties of SN 2021ckj being almost identical to those of SN 2021csp. Spectral modeling of SN 2021ckj reveals that its composition is dominated by oxygen, carbon, and iron group elements, and the photospheric velocity at peak is ∼10 000 km s−1. Modeling the spectral time series of SN 2021ckj suggests aspherical SN ejecta. From the light curve (LC) modeling applied to SNe 2021ckj, 2019hgp, and 2021csp, we find that the ejecta and CSM properties of Type Icn SNe are diverse. SNe 2021ckj and 2021csp likely have two ejecta components (an aspherical high-energy component and a spherical standard-energy component) with a roughly spherical CSM, while SN 2019hgp can be explained by a spherical ejecta-CSM interaction alone. The ejecta of SNe 2021ckj and 2021csp have larger energy per ejecta mass than the ejecta of SN 2019hgp. The density distribution of the CSM is similar in these three SNe, and is comparable to those of Type Ibn SNe. This may imply that the mass-loss mechanism is common between Type Icn (and also Type Ibn) SNe. The CSM masses of SN 2021ckj and SN 2021csp are higher than that of SN 2019hgp, although all these values are within those seen in Type Ibn SNe. The early spectrum of SN 2021ckj shows narrow emission lines from C II and C III, without a clear absorption component, in contrast with that observed in SN 2021csp. The similarity of the emission components of these lines implies that the emitting regions of SNe 2021ckj and 2021csp have similar ionization states, and thus suggests that they have similar properties as the ejecta and CSM, which is also inferred from the LC modeling. Taking the difference in the strength of the absorption features into account, this heterogeneity may be attributed to viewing angle effects in otherwise common aspherical ejecta. In particular, in this scenario SN 2021ckj is observed from the polar direction, while SN 2021csp is seen from an off-axis direction. This is also supported by the fact that the late-time spectra of SNe 2021ckj and 2021csp show similar features but with different line velocities.
Ultra-high energy cosmic rays with the Pierre Auger Observatory
Authors: Perrone Lorenzo
Published: March 2023

In the era of multi-messenger astronomy, ultra-high energy cosmic rays offer the unique opportunity to investigate the nature of astrophysical sources and of particle interactions in an energy range far beyond that covered by current particle accelerators. The Pierre Auger Observatory, the world’s largest cosmic ray detector, combines in a hybrid design the information from fluorescence telescopes, observing the longitudinal profile of extensive air showers, with a surface array, measuring the lateral distributions of secondary particles at the ground. A review of selected results is presented, focusing on the measurements of energy spectrum and chemical composition and on the search for neutral primary particles. The future prospects will also be discussed in light of the extensive upgrade program being now implemented to further improve the Observatory potential.
Astrophysical interpretation of Pierre Auger Observatory measurements of the UHECR energy spectrum and mass composition
Authors: Condorelli Antonio
Published: March 2023

We present a combined fit of a simple astrophysical model of Ultra-high-energy cosmic-ray sources to both the energy spectrum and mass composition data measured by the Pierre Auger Observatory. The astrophysical model we adopted consists of identical sources uniformly distributed in a comoving volume, where nuclei are accelerated with a rigidity-dependent mechanism. The fit has been performed at first for energies above 5 EeV, i.e., the region of the all-particle spectrum above the so-called “ankle” feature, and has then been extended to lower energies in order to include this feature. The fit results and their astrophysical implications in both cases are discussed.
Probing Hadronic Interactions with Cosmic Rays
Authors: Soldin Dennis
Published: March 2023

High-energy cosmic rays interact in the Earth’s atmosphere and produce extensive air showers (EASs) which can be measured with large detector arrays at the ground. The interpretation of these measurements relies on models of the EAS development which represents a challenge as well as an opportunity to test quantum chromodynamics (QCD) under extreme conditions. The EAS development is driven by hadron-ion collisions under low momentum transfer in the non-perturbative regime of QCD. Under these conditions, hadron production cannot be described using ﬁrst principles and these interactions cannot be probed with existing collider experiments. Thus, accurate measurements of the EAS development provide a unique probe of multi-particle production in hadronic interactions.
Exploiting synergies between neutrino telescopes for the next galactic core-collapse supernova
Authors: Bendahman Meriem , Buellet Anne-Cécile , Bugli Matteo , Coelho Joao , Coleiro Alexis , de Wasseige Gwenhaël , El Hedri Sonia , Foglizzo Thierry , Franco Davide , Goos Isabel , Guilet Jérôme , Kouchner Antoine , Tayalati Yahya , Tonazzo Alessandra , Volpe Cristina
Published: March 2023

Observing and characterizing the next galactic core-collapse supernova will be a critical step for neutrino experiments. Extracting information about the supernova progenitors and neutrino properties within minutes after an observation will in particular be crucial in order to optimize analysis strategies at other observatories. Moreover, certain classes of progenitors, with strong magnetic ﬁelds, could give rise to gamma-ray bursts but have been underinvestigated to date. In this contribution we propose a strategy to combine results from next-generation neutrino experiments, focusing notably on the determination of the progenitor mass and the neutrino mass ordering. Additionally, we investigate the impact of strong magnetic ﬁelds on neutrino observations, and demonstrate the detectability of the associated eﬀects in upcoming experiments.
Neutrinos from core-collapse supernovae at KM3NeT
Authors: Bendahman Meriem
Published: March 2023

The SN1987A supernova was the ﬁrst extragalactic neutrino de- tection, but no further observations have been made since. Detecting neutrinos from a galactic supernova would provide invaluable information on the supernova mechanism and particle behavior in dense environments, hence, improving the sensitivity of current and upcoming neutrino experiments is crucial. In this contribution, we discuss how the optical module design of the KM3NeT neutrino experiment would allow to observe supernova neutrinos. We present KM3NeT’s sensitivity to galactic supernovae and describe its associated online alert system for multi-messenger studies. Finally, we discuss KM3NeT’s ability to infer the supernova evolution from the time proﬁle of the associated neutrino emission.
Tracking millisecond pulsars responsible for the Fermi GeV excess
Authors: Berteaud Joanna , Calore Francesca , Clavel Maïca
Published: March 2023

More than 10 years ago, an excess of γ-ray photons coming from the Galactic center was discovered in the Fermi-LAT data. First attributed to dark matter, it has since been shown that it should have at least a partial stellar origin. One hypothesis is the presence of a population of millisecond pulsars (MSPs) confined in the Galactic bulge. We here present our recent progress in the selection of MSP candidates.
Teufel mit Engelsflügeln – wenn Vitamin A Leben rettet
Authors: Benoit Tobias Matthieu , Gundermann Stefan
Published: March 2023

Anamnese und klinischer Befund Ein 40-jähriger, bislang gesunder Patient stellte sich mit neu aufgetretener, hämorrhagischer Diathese auf unserer Notfallstation vor. Klinisch fanden sich ausgeprägte Blutungsstigmata mit großflächigen Ekchymosen im Bereich der Oberschenkel sowie enorale Schleimhauteinblutungen, bei sonst allgemeinem Wohlbefinden.

Untersuchungen Die durchgeführte Gerinnungsdiagnostik war mit dem Bild einer disseminierten intravasalen Verbrauchskoagulopathie vereinbar. Im mikroskopischen Blutbild fand sich zudem eine leukämische Ausschwemmung von 74% morphologisch atypischen Promyelozyten.

Diagnose, Therapie und Verlauf Die in der Folge durchgeführte Knochenmarkdiagnostik stellte die Diagnose einer akuten Promyelozytenleukämie (mikrogranulärer Variante). Neben der Gerinnungsoptimierung wurde noch vor Diagnosebestätigung auf der Notfallstation eine Therapie mit der Vitamin-A-Säure Tretinoin (engl. all-trans retinoic acid, ATRA) eingeleitet, welche im Verlauf um Arsentrioxid (ATO) und das Anthrazyklin Idarubicin ergänzt wurde. Erfreulicherweise zeigte sich ein komplikationsarmer weiterer Verlauf. Der Patient ist zudem hinsichtlich der akuten Promyelozytenleukämie aktuell in kompletter Remission.

Folgerungen Die akute Promyelozytenleukämie macht etwa 10–15% aller akuten myeloischen Leukämien aus, geht initial häufig mit einer ausgeprägten Gerinnungsaktivierung im Sinne einer disseminierten intravasalen Verbrauchskoagulopathie einher und verläuft unbehandelt rasch tödlich. Eine rasche und bereits bei Diagnoseverdacht eingeleitete Therapie mit ATRA, wie auch eine Gerinnungsoptimierung, sind prognostisch entscheidend.
Substrates, Cofactors, and Cellular Targets of Coagulation Factor XIa
Authors: Lira André L. , Kohs Tia C.L. , Moellmer Samantha A. , Shatzel Joseph J. , McCarty Owen J.T. , Puy Cristina
Published: March 2023

Coagulation factor XI (FXI) has increasingly been shown to play an integral role in several physiologic and pathological processes. FXI is among several zymogens within the blood coagulation cascade that are activated by proteolytic cleavage, with FXI converting to the active serine protease form (FXIa). The evolutionary origins of FXI trace back to duplication of the gene that transcribes plasma prekallikrein, a key factor in the plasma kallikrein–kinin system, before further genetic divergence led to FXI playing a unique role in blood coagulation. While FXIa is canonically known for activating the intrinsic pathway of coagulation by catalyzing the conversion of FIX into FIXa, it is promiscuous in nature and has been shown to contribute to thrombin generation independent of FIX. In addition to its role in the intrinsic pathway of coagulation, FXI also interacts with platelets, endothelial cells, and mediates the inflammatory response through activation of FXII and cleavage of high-molecular-weight kininogen to generate bradykinin. In this manuscript, we critically review the current body of knowledge surrounding how FXI navigates the interplay of hemostasis, inflammatory processes, and the immune response and highlight future avenues for research. As FXI continues to be clinically explored as a druggable therapeutic target, understanding how this coagulation factor fits into physiological and disease mechanisms becomes increasingly important.
Novel Insights into Heterozygous Factor XIII Deficiency
Authors: Dorgalaleh Akbar
Published: March 2023

The prevalence and clinical significance of heterozygous factor XIII (FXIII) deficiency has long been debated, with controversial reports emerging since 1988. In the absence of large epidemiologic studies, but based on a few studies, a prevalence of 1 per 1,000 to 5,000 is estimated. In southeastern Iran, a hotspot area for the disorder, a study of more than 3,500 individuals found an incidence of 3.5%. Between 1988 and 2023, a total of 308 individuals were found with heterozygous FXIII deficiency, of which molecular, laboratory, and clinical presentations were available for 207 individuals. A total of 49 variants were found in the F13A gene, most of which were missense (61.2%), followed by nonsense (12.2%) and small deletions (12.2%), most occurring in the catalytic domain (52.1%) of the FXIII-A protein and most frequently in exon 4 (17%) of the F13A gene. This pattern is relatively similar to homozygous (severe) FXIII deficiency. In general, heterozygous FXIII deficiency is an asymptomatic condition without spontaneous bleeding tendency, but it can lead to hemorrhagic complications in hemostatic challenges such as trauma, surgery, childbirth, and pregnancy. Postoperative bleeding, postpartum hemorrhage, and miscarriage are the most common clinical manifestations, while impaired wound healing has been rarely reported. Although some of these clinical manifestations can also be observed in the general population, they are more common in heterozygous FXIII deficiency. While studies of heterozygous FXIII deficiency conducted over the past 35 years have shed light on some of the ambiguities of this condition, further studies on a large number of heterozygotes are needed to answer the major questions related to heterozygous FXIII deficiency.
Development of inverted pendulum thrust stand with spring-shaped wire for high power electric thrusters
Authors: Yamasaki J. , Nonaka M. , Yokota S. , Shimamura K.
Published: March 2023

Pendulum thrust stands are used to measure the thrust of electric propulsion systems for spacecraft. A thruster is mounted on a pendulum and operated, and the pendulum displacement due to thrust is measured. In this type of measurement, the pendulum is also affected by nonlinear tensions due to wiring and piping that deteriorate the accuracy of the measurement. This influence cannot be ignored in high power electric propulsion systems because complicated piping and thick wirings are required. Therefore, to reduce the influence of tension due to wires and tubes, we developed an inverted pendulum-type thrust stand with pipes and wirings as springs. In this paper, we first derive the design guidelines for spring-shaped wires; the necessary conditions for sensitivity, responsivity, spring shape, and electric wire were formulated. Next, a thrust stand was designed and fabricated based on these guidelines, and the performance of the stand was evaluated through calibration and thrust measurements using a 1 kW-class magneto-plasma-dynamics thruster. The sensitivity of the thrust stand was 17 mN/V, the normalized standard deviation of the variation of the measured values owing to the structure of the thrust stand was 1.8 × 10−3, and the thermal drift during the long-time operation was ∼4.5 × 10−3 mN/s.
On quantitative hypocoercivity estimates based on Harris-type theorems
Authors: Yoldaş Havva
Published: March 2023

This Review concerns recent results on the quantitative study of convergence toward the stationary state for spatially inhomogeneous kinetic equations. We focus on analytical results obtained by means of certain probabilistic techniques from the ergodic theory of Markov processes. These techniques are sometimes referred to as Harris-type theorems. They provide constructive proofs for convergence results in the L1 (or total variation) setting for a large class of initial data. The convergence rates can be made explicit (for both geometric and sub-geometric rates) by tracking the constants appearing in the hypotheses. Harris-type theorems are particularly well-adapted for equations exhibiting non-explicit and non-equilibrium steady states since they do not require prior information on the existence of stationary states. This allows for significant improvements of some already-existing results by relaxing assumptions and providing explicit convergence rates. We aim to present Harris-type theorems, providing a guideline on how to apply these techniques to kinetic equations at hand. We discuss recent quantitative results obtained for kinetic equations in gas theory and mathematical biology, giving some perspectives on potential extensions to nonlinear equations.
Development of a biaxial apparatus for jamming profiles of photoelastic granular media
Authors: Zheng Hu , Dai Guowei , Bester Cacey Stevens , Wang Meimei , Wang Dong
Published: March 2023

We describe a two-dimensional biaxial apparatus that is used to conduct the experimental study of the jamming of granular media. The setup is designed based on the photoelastic imaging technique, which allows us to detect force-bearing contacts among particles, calculate the pressure on each particle according to the mean squared intensity gradient method, and compute contact forces on each particle [T. S. Majmudar and R. P. Behringer, Nature 435, 1079–1082 (2005)]. Particles float in a density-matched solution to avoid basal friction during experiments. We can compress (uniaxially or biaxially) or shear the granular system by an entangled comb geometry by moving the paired boundary walls independently. A novel design for the corner of each pair of perpendicular walls is described, which allows for independent motion. We control the system using a Raspberry Pi with Python code. Three typical experiments are described briefly. Furthermore, more complicated experiment protocols can be implemented to achieve specific granular materials research goals.
From Turing patterns to chimera states in the 2D Brusselator model
Authors: Provata A.
Published: March 2023

The Brusselator has been used as a prototype model for autocatalytic reactions and, in particular, for the Belousov–Zhabotinsky reaction. When coupled at the diffusive limit, the Brusselator undergoes a Turing bifurcation resulting in the formation of classical Turing patterns, such as spots, stripes, and spirals in two spatial dimensions. In the present study, we use generic nonlocally coupled Brusselators and show that in the limit of the coupling range R→1 (diffusive limit), the classical Turing patterns are recovered, while for intermediate coupling ranges and appropriate parameter values, chimera states are produced. This study demonstrates how the parameters of a typical nonlinear oscillator can be tuned so that the coupled system passes from spatially stable Turing structures to dynamical spatiotemporal chimera states.
Acceptor and compensating donor doping of single crystalline SnO (001) films grown by molecular beam epitaxy and its perspectives for optoelectronics and gas-sensing
Authors: Egbo Kingsley , Lähnemann Jonas , Falkenstein Andreas , Varley Joel , Bierwagen Oliver
Published: March 2023

(La and Ga)-doped tin monoxide [stannous oxide, tin (II) oxide, SnO] thin films were grown by plasma-assisted and suboxide molecular beam epitaxy with dopant concentrations ranging from ≈ 5 × 1018 to 2 × 1021 cm−3. In this concentration range, the incorporation of Ga into SnO was limited by the formation of secondary phases observed at 1.2 × 1021 cm−3 Ga, while the incorporation of La showed a lower solubility limit. Transport measurements on the doped samples reveal that Ga acts as an acceptor and La as a compensating donor. While Ga doping led to an increase in the hole concentration from 1 × 1018−1 × 1019 cm−3 for unintentionally doped (UID) SnO up to 5 × 1019 cm−3, La-concentrations well in excess of the UID acceptor concentration resulted in semi-insulating films without detectable n-type conductivity. Ab initio calculations qualitatively agree with our dopant assignment of Ga and La and further predict InSn to act as an acceptor as well as AlSn and BSn as donors. These results show the possibilities of controlling the hole concentration in p-type SnO, which can be useful for a range of optoelectronic and gas-sensing applications.
In situ syringe rotation system for heavy microparticle suspension stability in electrospinning technique
Authors: Trupp Federico , Barella Matías , Cibils Roberto , Goyanes Silvia
Published: March 2023

Electrospinning allows the fabrication of polymeric nonwovens with a wide variety of inclusions in the micro-nanofibers. However, the electrospinning of microparticle-filled polymer solutions is still limited in particle size, density, and concentration, mainly due to suspension instability during the electrospinning process, so it is not commonly investigated despite the vast number of possible applications. In this study, a simple and effective novel rotation device was developed to prevent the settling of microparticles in the polymer solution during electrospinning. The stability of polyvinyl alcohol and polyvinylidene fluoride (PVDF) solutions with indium microparticles (IMPs) of (42 ± 7) μm diameter was evaluated using LASER transmittance inside a syringe, both static and rotating for 24 h. While the static suspensions completely settled at 7 min and 9 h, respectively, depending on solution viscosity, the rotating suspensions remained stable throughout the experiment. The number and distribution of IMPs in PVDF electrospun mats were determined by optic microscopy and a novel x-ray imaging mapping method, showing 165% more IMPs in the mat obtained with the rotating syringe device. A simple analysis of the theoretical background of settling and rotating suspensions was included to understand the working mechanism of the device. Also, the electrospinning of solutions with high loadings of IMPs (up to 400% w/w PVDF) was accomplished. The simplicity and outstanding efficiency of the device shown in this work may serve as a solution to technical difficulties and as an encouragement to future research in microparticle-filled solution electrospinning.
A short high-gain waveguide amplifier based on low concentration erbium-doped thin-film lithium niobate on insulator
Authors: Yan Congliao , Wang Shaoqian , Zhao Sheng , Huang Yulei , Deng Guoliang , Wang Sha , Zhou Shouhuan
Published: March 2023

One hotspot of integrated optics is how to realize a highly integrated and high-gain on-chip amplification system in a thin film of lithium niobate on insulator (TFLNOI). Here, a low erbium-doped TFLNOI waveguide amplifier with shorter length is demonstrated using the photolithography-assisted oblique-reactive ion etching technique. A maximum net internal gain of 5.4 dB in the small-signal-gain regime is measured at the peak emission wavelength of 1531.35 nm for a waveguide length of 1.5 mm and an erbium-doped concentration of 0.1 mol. %, indicating a gain per unit length of 36 dB cm−1. This work paves the way for the monolithic integration of diverse active and passive photonic components on the TFLNOI platform.
Enhancement of spin–orbit torque in Pt/Co/HfOx heterostructures with voltage-controlled oxygen ion migration
Authors: Wu S. , Jin T. L. , Tan F. N. , Ang C. C. I. , Poh H. Y. , Lim G. J. , Lew W. S.
Published: March 2023

Spin–orbit torque (SOT) induced magnetization switching and SOT modulation by interfacial coupling exhibit good potential in spintronic devices. In this work, we report the enhancement of damping-like field and SOT efficiency of up to 60% and 23%, respectively, in perpendicularly magnetized Pt/Co/HfOx heterostructures over a Pt/Co system at an optimal thickness of 2 nm HfOx. The SOT improvement is primarily attributed to the interfacial oxidization of the Co layer, and the strength is tunable via voltage-induced oxygen ion migration at the Co/HfOx interface. Our measurement reveals that by controlling gate voltages, the Co oxidation can be increased, which leads to the SOT efficiency enhancement. Our work promotes the SOT enhancement and modulation by oxidation effects for energy-efficient spintronic devices.
Internal stress effects on the piezoelectric properties of Pb(Zr,Ti)O3 superlattice thin films grown on Si substrates
Authors: Kimura Goki , Kweon Sang-Hyo , Tanaka Kiyotaka , Sato Yukio , Kanno Isaku
Published: March 2023

Artificial superlattice thin films of lead zirconate titanate (PZT) were epitaxially grown on silicon substrates, and the influence of superlattice strain on their piezoelectric properties was investigated. The c-axis oriented PZT superlattice thin film consists of two different PZT layers, Pb(Zr0.65Ti0.35)O3 (PZT-65) and Pb(ZrxTi1−x)O3 (PZT-X: x = X/100 = 0.3–0.9), with a 4 nm period. Satellite peaks were clearly observed in x-ray diffraction patterns, and cross-sectional composition measurements confirmed the superlattice structure with good interfaces, showing an alternate change in Zr and Ti compositions. Ferroelectric properties varied significantly depending on the PZT-X composition, and in particular, the PZT-65/PZT-30 superlattice thin film showed nearly the same ferroelectricity as the tetragonal phase under a large compressive strain of PZT-65 from the PZT-30 layer. For the PZT-65/PZT-X (X = 30–58) superlattice thin films, the PZT-65 layers received a compressive strain, and a relatively large piezoelectric coefficient, which did not depend on the PZT-X composition, was obtained. However, a decrease in piezoelectricity was observed in PZT-65/PZT-X (X = 70 and 90), where the PZT-65 layers experienced tensile strain. This result indicates that the piezoelectric properties of PZT superlattice thin films can be controlled by the interlayer strain.
Electrode pattern definition in ultrasound power transfer systems
Authors: Sayed Ahmed Moustafa , Shahab Shima
Published: March 2023

We use a high pattern-fidelity technique on piezoelectric electrodes to selectively excite high-order vibration modes, while isolating other modes, in multi-layered through-wall ultrasound power transfer (TWUPT) systems. Physical mechanisms, such as direct and inverse piezoelectric effects at transmitting and receiving piezoelectric elements, as well as wave propagation across an elastic barrier and coupling layers, all contribute to TWUPT. High-order radial modes in a TWUPT system feature strain nodes, where the dynamic strain distribution changes sign in the direction of disks' radii. This study explains theoretically and empirically how covering the strain nodes of vibration modes with continuous electrodes results in substantial cancelations of the electrical outputs. A detailed analysis is given for predicting the locations of the strain nodes. The electrode patterning for creating the transmitter and receiver shapes is determined by the regions where local force and charge cancelation do not occur, i.e., the two modal principal stress components have the same sign. Patterning for creating the electrode shapes is performed by high-fidelity numerical modeling supported by experiments. Using differential excitation on the transmitter side while monitoring transmitted power and efficiency on the reception side at various vibration modes is made possible by the unique nature of TWUPT systems. Due to an improvement in system quality and power factors, it is determined that employing the proposed electrode pattern designs enhances overall device efficiency and active power. The suppression of other modes makes up a filter feature that is paired with the enhancement at the mode under consideration.
Alkali-earth metal ion inducing multiphase transition of lanthanum-free Pb(Zr0.5Sn0.5)O3 ceramics improves the energy storage properties
Authors: Ge Guanglong , Chen Chukai , Shi Cheng , Yang Jing , Lin Jinfeng , Qian Jin , Wei Yongqi , Shen Bo , Zhai Jiwei
Published: March 2023

Constructing the stepwise phase transition can delay the polarization process of antiferroelectric ceramics, possessing certain significance for improving the energy storage density. However, the common multiphase transitions are obtained in the rare-earth ions doped PbZrO3-based systems. In the present work, the multiphase transition can also be induced in the lanthanum-free Pb(Zr0.5Sn0.5)O3 matrix with mere doping of the alkali-earth metal ion Sr. The introduction of Sr endows the matrix with a higher lattice distortion and the reduced phase-transition temperature. Moreover, related to the induced stepwise electric field-induced phase transition, the energy storage properties are remarkably enhanced to 10.5 J/cm3 and 83.2% when the substitution content of Sr is 3 mol. %. Sr modification can adjust the phase structure by regulating the phase stability of the matrix and suppress the leakage current originating from the structural changes. This work provides a successful attempt that the phase structure and energy storage performance of antiferroelectric ceramics can also be effectively controlled through cheaper and simpler element modification. The optimized energy storage performance provides a new material selection for pulsed power devices.
Thin-film lithium niobate electro-optic modulators: To etch or not to etch
Authors: Mookherjea Shayan , Mere Viphretuo , Valdez Forrest
Published: March 2023

This Perspective discusses and compares several different approaches to the design of high-bandwidth, low-voltage electro-optic devices, such as Mach–Zehnder modulators, made using thin-film lithium niobate (TFLN) and strategies for their incorporation as part of a larger photonic integrated circuit (PIC).
Dithioester-terminated copolymers with simultaneous high dielectric constant and breakdown strength for energy storage
Authors: Feng Yang , Li Mingru , Shang Kai , Niu Huan , Qu Guanghao , Lu Guanghao , Li Shengtao
Published: March 2023

High-energy storable polymer dielectrics are highly desirable and applicable for compact and efficient power electronic devices. However, existing polymer dielectrics suffer from either a low dielectric constant or a low breakdown strength and exhibit an extremely low energy density. Here, the reversible addition−fragmentation chain transfer polymerization and polyaddition polymerization techniques are combined to create a dithioester-terminated polythiourea (PTU)-based copolymer dielectric with an extraordinarily high energy density of 10.7 J/cm3. The end-group functionalized copolymer significantly increases the dielectric constant from 6.0 to 7.6, which enhances the breakdown strength from 264 to 563 MV/m. The theoretical analysis from the proton nuclear magnetic resonance, atomic force microscope (AFM), and the dynamics of the polarization behaviors demonstrates conformational transitions between the two distinct trans/trans and cis/trans thioureas, along with the formation of polar PTU nanoregions. These result in a flexible polarization reorientation process and increased dielectric constant. Meanwhile, the density functional theory calculations for the electronic structures of the block copolymers indicate that the excellent breakdown strength of the end-group functionalized copolymer is attributed to strong charge trapping from the unique dithioesters. This work proposes a strategy to achieve a simultaneous high dielectric constant and breakdown strength toward excellent energy storage performances by end-group functionalization and composition modifications.
Uncovering the bridging role of slow atoms in unusual caged dynamics and β-relaxation of binary metallic glasses
Authors: Chen Yuxuan , Feng Shidong , Lu Xiaoqian , Pan Shaopeng , Xia Chaoqun , Wang Li-Min
Published: March 2023

The origin of β-relaxation in metallic glasses is still not fully understood, and the guidance of slow atoms for caged dynamics and β-relaxation is rarely mentioned. Using molecular dynamics simulations, we reveal the bridging role of slow atoms on unusual caged dynamics and β-relaxation. In the stage of unusual caged dynamics, slow atoms are bounded by neighboring atoms. It is difficult for the slow atoms to break the cage, producing more high-frequency vibration, which causes more atoms to jump out of the cage randomly in the next stage. Precisely, the movement of the slow atoms changes from individual atoms vibrating inside the cage and gradually breaking out of the cage into a string-like pattern. The string-like collective atomic jumps cause decay of the cages, inducing β-relaxation. This situation generally exists in binary systems with the large atomic mass difference. This work offers valuable insights for understanding the role of slow atoms in unusual caged dynamics and β-relaxation, complementing studies on the origin of β-relaxation in metallic glasses and their glass-forming liquids.
Study on the early strength characteristics and source mechanism of solidified dredged marine sediment based on moisture transformation
Authors: Xu Haoqing , Liu Songyu , Gan Yaxiong , Jiang Pengming , Zhou Aizhao , Qi Yongzheng
Published: March 2023

Context Large land areas are occupied by dredged sediments with which the strength of the solidified soil develops slowly, and this has become an instant problem in geotechnical engineering. Aims This study was designed to investigate the performance of solidified dredged deposits treated by sulfoaluminate cement for sludge solidification, and whether the mechanism for early strength development is based on water transfer. Methods With sediments dredged from Dalian Bay as the research objects, the strength, deformation and amount of moisture transferred by the solidified sludge were measured and analysed and referred to the data for Portland cement. Key results Sulfate aluminium cement is characterised by great early strength. Conclusion The mechanism for early strength development relies on reactions that form crystalline calcium vanadium stone. Implications Our study showed that calcium vanadium stone plays a critical role in early strength development, and this was measured quantitatively for the mineral water form.
Projecting live fuel moisture content via deep learning
Authors: Miller Lynn , Zhu Liujun , Yebra Marta , Rüdiger Christoph , Webb Geoffrey I.
Published: March 2023

Background Live fuel moisture content (LFMC) is a key environmental indicator used to monitor for high wildfire risk conditions. Many statistical models have been proposed to predict LFMC from remotely sensed data; however, almost all these estimate current LFMC (nowcasting models). Accurate modelling of LFMC in advance (projection models) would provide wildfire managers with more timely information for assessing and preparing for wildfire risk. Aims The aim of this study was to investigate the potential for deep learning models to predict LFMC across the continental United States 3 months in advance. Method Temporal convolutional networks were trained and evaluated using a large database of field measured samples, as well as year-long time series of MODerate resolution Imaging Spectroradiometer (MODIS) reflectance data and Parameter-elevation Relationships on Independent Slopes Model (PRISM) meteorological data. Key results The proposed 3-month projection model achieved an accuracy (root mean squared error (RMSE) 27.52%; R2 0.47) close to that of the nowcasting model (RMSE 26.52%; R2 0.51). Conclusions The study is the first to predict LFMC with a 3-month lead-time, demonstrating the potential for deep learning models to make reliable LFMC projections. Implications These findings are beneficial for wildfire management and risk assessment, showing proof-of-concept for providing advance information useful to help mitigate the effect of catastrophic wildfires.
COVID-19 precautionary behaviors and vaccine acceptance among older individuals: The role of close kin
Authors: Arpino Bruno , Bordone Valeria , Di Gessa Giorgio
Published: March 2023

The family plays a central role in shaping health behaviors of its members through social control and support mechanisms. We investigate whether and to what extent close kin (i.e., partner and children) matter for older people in taking on precautionary behaviors (e.g., wearing a mask) and vaccination during the COVID-19 pandemic in Europe. Drawing on data from the Survey of Health, Ageing and Retirement in Europe (SHARE), we combine its Corona Surveys (June to September 2020 and June to August 2021) with pre-COVID information (October 2019 to March 2020). We find that having close kin (especially a partner) is associated with a higher probability of both adopting precautionary behaviors and accepting a COVID-19 vaccine. Results are robust to controlling for other potential drivers of precautionary behaviors and vaccine acceptance and to accounting for coresidence with kin. Our findings suggest that policymakers and practitioners may differently address kinless individuals when promoting public policy measures.
Intercalant-induced V
t

2

g

orbital occupation in vanadium oxide cathode toward fast-charging aqueous zinc-ion batteries
Authors: Wang Yixiu , Wei Shiqiang , Qi Zheng-Hang , Chen Shuangming , Zhu Kefu , Ding Honghe , Cao Yuyang , Zhou Quan , Wang Changda , Zhang Pengjun , Guo Xin , Yang Xiya , Wu Xiaojun , Song Li
Published: March 2023

Intercalation-type layered oxides have been widely explored as cathode materials for aqueous zinc-ion batteries (ZIBs). Although high-rate capability has been achieved based on the pillar effect of various intercalants for widening interlayer space, an in-depth understanding of atomic orbital variations induced by intercalants is still unknown. Herein, we design an NH
4
+
-intercalated vanadium oxide (NH
4
+
-V
2
O
5
) for high-rate ZIBs, together with deeply investigating the role of the intercalant in terms of atomic orbital. Besides extended layer spacing, our X-ray spectroscopies reveal that the insertion of NH
4
+
could promote electron transition to 3

d
xy

state of V
t

2

g

orbital in V
2
O
5
, which significantly accelerates the electron transfer and Zn-ion migration, further verified by DFT calculations. As results, the NH
4
+
-V
2
O
5
electrode delivers a high capacity of 430.0 mA h g
−1
at 0.1 A g
−1
, especially excellent rate capability (101.0 mA h g
−1
at 200 C), enabling fast charging within 18 s. Moreover, the reversible V
t

2

g

orbital and lattice space variation during cycling are found via ex-situ soft X-ray absorption spectrum and in-situ synchrotron radiation X-ray diffraction, respectively. This work provides an insight at orbital level in advanced cathode materials.
Human brain effects of DMT assessed via EEG-fMRI
Authors: Timmermann Christopher , Roseman Leor , Haridas Sharad , Rosas Fernando E. , Luan Lisa , Kettner Hannes , Martell Jonny , Erritzoe David , Tagliazucchi Enzo , Pallavicini Carla , Girn Manesh , Alamia Andrea , Leech Robert , Nutt David J. , Carhart-Harris Robin L.
Published: March 2023

Psychedelics have attracted medical interest, but their effects on human brain function are incompletely understood. In a comprehensive, within-subjects, placebo-controlled design, we acquired multimodal neuroimaging [i.e., EEG-fMRI (electroencephalography-functional MRI)] data to assess the effects of intravenous (IV) N,N-Dimethyltryptamine (DMT) on brain function in 20 healthy volunteers. Simultaneous EEG-fMRI was acquired prior to, during, and after a bolus IV administration of 20 mg DMT, and, separately, placebo. At dosages consistent with the present study, DMT, a serotonin 2A receptor (5-HT2AR) agonist, induces a deeply immersive and radically altered state of consciousness. DMT is thus a useful research tool for probing the neural correlates of conscious experience. Here, fMRI results revealed robust increases in global functional connectivity (GFC), network disintegration and desegregation, and a compression of the principal cortical gradient under DMT. GFC × subjective intensity maps correlated with independent positron emission tomography (PET)-derived 5-HT2AR maps, and both overlapped with meta-analytical data implying human-specific psychological functions. Changes in major EEG-measured neurophysiological properties correlated with specific changes in various fMRI metrics, enriching our understanding of the neural basis of DMT’s effects. The present findings advance on previous work by confirming a predominant action of DMT—and likely other 5-HT2AR agonist psychedelics—on the brain’s transmodal association pole, i.e., the neurodevelopmentally and evolutionarily recent cortex that is associated with species-specific psychological advancements, and high expression of 5-HT2A receptors.
Ezafe as a linking feature within DP
Authors: Gündoğdu Songül , Erbasi Betul
Published: March 2023

Studies on Ezafe demonstrate that it displays considerable cross-linguistic variation, making it difficult to propose a unified analysis. Our goal is to achieve such unification by investigating the properties of Ezafe in two typologically different languages; Northern Kurdish/Kurmanji Kurdish (Iranian) and Turkish (Turkic). Taking Ezafe as a linking feature that marks dependency between the head and the non-head elements within the nominal domain, we propose that the variation can be explained with the head directionality of the language and the phase domain where the head noun lands in/remains. This allows us to account for data that were problematic for previous accounts and to extend the range of data to languages (specifically, Turkish) that have not been analyzed as Ezafe languages before.
RMO SC comparison COOMET.M.H-S3
Authors: Skliarov V , Menelao F , Borovský J , Zhamanbalin M , Obozny E , Kamkova N
Published: March 2023

Main text

This report describes the results of comparison COOMET.M.H-S3. The comparison measurements between the five participants NSC "IM" (pilot laboratory), PTB, CMI, BelGIM, KazInSt were started in December 2014 and ended in December 2016. In the RMO SC, one set of hardness reference blocks was used consisting of 6 (six) blocks of the Superficial-Rockwell scales and hardness levels 90-94 HR15N, 40-50 HR30N, 76-84 HR30N, 43-54 HR45N, 47-53 HR30TW, 70-82 HR30TW. Agreement between the results of the participants is good.

To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/.

The final report has been peer-reviewed and approved for publication by the CCM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).