bluuebunny/crossref_metadata_2025 huggingface dataset:
Enhanced deep red to near-infrared (DR-NIR) phosphorescence in cyclometalated iridium(iii) complexes
Authors: Yoon Sungwon , Teets Thomas S.
Published: November 2022

Bis-cyclometalated iridium complexes with highly conjugated cyclometalating ligands and electron-rich ancillary ligands have exceptional quantum yields for deep-red to near-infrared phosphorescence.
Regulation strategy of white emission from organic–inorganic hybrid metal halide perovskites
Authors: Kang Liwen , Lin Zhenghuan
Published: November 2022

In this review, the structure, photophysical properties, and white-light mechanism of organic–inorganic hybrid metal halide perovskites with white emission are summarized, with an emphasis on the adjustment strategy for white-light performance.
Syntheses and applications of mesoporous hydroxyapatite: a review
Authors: Oni Olaiya Peter , Hu Yan , Tang Sijie , Yan Honghan , Zeng Hao , Wang Huimin , Ma Liya , Yang Changying , Ran Jiabing
Published: November 2022

A systematic summary of synthesis strategies and applications of mesoporous hydroxyapatite.
Blue photoluminescence enhancement achieved by zero-dimensional organic indium halidesviaa metal ion doping strategy
Authors: Lin Fang , Yu Guicheng , Weng Shuchen , Zhou Chao , Han Yonglei , Liu Wei , Zhou Kang , Wang Yongfei , Lin Haoran
Published: November 2022

PLQE enhancement and emission manipulation have been achieved for zero-dimensional (MA)4InCl7through a metal ion doping strategy. Cs+or Mn2+doping result in defect passivation and homogeneous crystals, while Sb3+doping shift the emission center.
Compartmentalizing and sculpting nanovesicles by phase-separated aqueous nanodroplets
Authors: Sabet Fatemeh Kazemi , Bahrami Arash , Bahrami Amir H.
Published: November 2022

Internal aqueous nanodroplets form novel stable and long-lived unstable nanovesicles, exclusive to the nanoscale and crucial for membrane nanostructures.
Formulation of water-dispersible hydrophobic compound nanocomplexes with polypeptides via a supramolecular approach using a high-speed vibration milling technique
Authors: Kawamura Shogo , Kawasaki Riku , Hino Shodai , Yamana Keita , Okuno Masafumi , Eto Takuro , Ikeda Atsushi
Published: November 2022

Polypeptides were used to solubilize functional hydrophobic molecules via a high-speed vibrational milling method.
Grass-like alumina nanoelectrodes for hierarchical porous silicon supercapacitors
Authors: Isakov Kirill , Sorsa Olli , Rauhala Taina , Saxelin Santeri , Kallio Tanja , Lipsanen Harri , Kauppinen Christoffer
Published: November 2022

We demonstrate a new kind of conformal nanoelectrode for hierarchical supercapacitors made by ALD. This grass-like alumina (GLA) nanoelectrode increases the capacitance of PS supercapacitors fourfold or 4× and consists of a TiN-GLA-TiN stack.
The Automated Photometry of Transients pipeline (AutoPhOT)
Authors: Brennan S. J. , Fraser M.
Published: November 2022

We present the Automated Photometry of Transients (AutoPhOT) package, a novel automated pipeline that is designed for rapid, publication-quality photometry of astronomical transients. AutoPhOT is built from the ground up using Python3 – with no dependencies on legacy software. Capabilities of AutoPhOT include aperture and point-spread-function photometry, template subtraction, and calculation of limiting magnitudes through artificial source injection. AutoPhOT is also capable of calibrating photometry against either survey catalogues, or using a custom set of local photometric standards, and is designed primarily for ground-based optical and infrared images. We show that both aperture and point-spread-function photometry from AutoPhOT is consistent with commonly used software, for example, DAOPHOT, and also demonstrate that AutoPhOT can reproduce published light curves for a selection of transients with minimal human intervention.
Morphology-density relation, quenching, and mergers in CARLA clusters and protoclusters at 1.4 < z < 2.8
Authors: Mei Simona , Hatch Nina A. , Amodeo Stefania , Afanasiev Anton V. , De Breuck Carlos , Stern Daniel , Cooke Elizabeth A. , Gonzalez Anthony H. , Noirot Gaël , Rettura Alessandro , Seymour Nick , Stanford Spencer A. , Vernet Joël , Wylezalek Dominika
Published: November 2022

At redshifts of z ≲ 1.3, early-type galaxies (ETGs) and passive galaxies are mainly found in dense environments, such as galaxy clusters. However, it remains unclear whether these well-known morphology-density and passive-density relations have already been established at higher redshifts. To address this question, we performed an in-depth study of galaxies in 16 spectroscopically confirmed clusters at 1.3 < z < 2.8 from the Clusters Around Radio-Loud AGN (CARLA) survey. Our clusters span a total stellar mass in the range of 11.3 < log(M∗c/M⊙) < 12.6 (approximate halo mass in the range of 13.5 ≲ log(Mhc/M⊙) ≲ 14.5). Our main finding is that the morphology-density and passive-density relations are already in place at z ∼ 2. The cluster at z = 2.8 shows a similar fraction of ETG as in the other clusters in its densest region, however, only one cluster does not provide enough statistics to confirm that the morphology-density relation is already in place at z ∼ 3. The cluster ETG and passive fractions depend mainly on local environment and only slightly on galaxy mass; also, they do not depend on the global environment. At lower local densities, where ΣN < 700 gal/Mpc2, the CARLA clusters exhibit a similar ETG fraction as the field, in contradiction to clusters at z = 1, which already exhibit higher ETG fractions. This implies that the densest regions influence the morphology of galaxies first, with lower density local environments either taking longer or only influencing galaxy morphology at later cosmological times. Interestingly, we find evidence of high merger fractions in our clusters with respect to the CANDELS fields, but the merger fractions do not significantly depend on local environment. This suggests that merger remnants in the lowest density regions can reform disks fueled by cold gas flows, but those in the highest density regions are cut off from the gas supply and will become passive ETGs. The percentages of active ETGs, with respect to the total ETG population, are 21 ± 6% and 59 ± 14% at 1.35 < z < 1.65 and 1.65 < z < 2.05, respectively, and about half of them are mergers or asymmetric in both redshift bins. All the spectroscopically confirmed CARLA clusters have properties that are consistent with clusters and proto-clusters, confirming that radio-loud active galactic nuclei are lighthouses for dense environments. The differences between our results and other findings that point to enhanced star formation and starbursts in cluster cores at similar redshifts are probably due to differences in the sample selection criteria; for example, selection of different environments hosting galaxies with different accretion and pre-processing histories.
Sulfur abundances in three Galactic clusters: Ruprecht 106, Trumpler 5, and Trumpler 20
Authors: Lucertini F. , Monaco L. , Caffau E. , Mucciarelli A. , Villanova S. , Bonifacio P. , Sbordone L.
Published: November 2022

Context. Sulfur (S) is one of the lesser-studied α-elements. Published investigations of its behavior have so far focused on local stars, and only a few clusters of the Milky Way have been considered to study this topic. We aim to study the S content of the globular cluster Ruprecht 106 – which has never before been studied for this purpose, but is known to present low levels of the [α/Fe] abundance ratio – and the open cluster Trumpler 5. The only star studied so far in Trumpler 5 shows an unexpectedly low abundance of S.

Aims. With this work, we aim to provide the first S abundance in Ruprecht 106 and to investigate the S content of Trumpler 5 with a larger sample of stars. The open cluster Trumpler 20 is considered as a reference object.

Methods. We performed a standard abundance analysis based on 1D model atmospheres in local thermodynamical equilibrium (LTE) and on high-resolution and high-signal-to-noise-ratio UVES-slit and UVES/FLAMES spectra. We also applied corrections for nonLTE. The metallicities of the targets were obtained by studying equivalent widths. Sulfur abundances were derived from multiplets 1, 6, and 8 by spectrosynthesis.

Results. We find that the metallicities of Ruprecht 106 and Trumpler 5 are [Fe/H] = −1.37±0.11 and [Fe/H] = −0.49±0.14, respectively. Ruprecht 106 is less S-rich than the other Galactic clusters at similar metallicity. The low S content of Ruprecht 106, [S/Fe]NLTE = −0.52±0.13, is consistent with its shortage of α-elements. This supports an extra-galactic origin of this cluster. We obtained a new and more robust S content value of Trumpler 5 of about [S/Fe]NLTE = 0.05±0.20. According to our results, Trumpler 5 follows the trend of the Galactic disk in the [S/Fe]LTE versus [Fe/H] diagram. Our results for Trumpler 20, of namely [Fe/H]= 0.06±0.15 and [S/Fe]NLTE = −0.28±0.21, are in agreement with those in the literature.
Krankenhausführung: Dezentralisierung ist das Gebot der Stunde
Authors: Bornemeier Olaf
Published: November 2022

Der diesjährige Gesundheitswirtschaftskongress in Hamburg wurde von Prof. Heinz Lohmann eröffnet mit den Worten, er habe noch nie so viele Krankenhausmanager wie derzeit „ratlos“ erlebt. Das deckt sich mit den Ergebnissen der kurz darauf erschienenen Roland Berger Krankenhausstudie 2022, wonach 96 Prozent der befragten Klinikmanager eine Verschlechterung ihrer wirtschaftlichen Situation erwarten.
Exkurs Linearbeschleuniger: Verantwortungsvoller Umgang mit Energie
Authors: Lang Michael
Published: November 2022

Im Testfeld KITTEN drehen Karlsruher Forscher an verschiedenen Stellschrauben, um den Energieverbrauch von Teilchenbeschleunigern zu senken.
Roboterassitierte Mikrochirurgie: Im Fokus
Authors: Hollmig Luisa-Maria
Published: November 2022

Mitte August feierte eine neue Operationsmethode weltweite Premiere in Münster. Bei der roboterassistierten Mikrochirurgie kommen gleich zwei Roboter zum Einsatz, die ein smartes und präzises Arbeiten ermöglichen.
Arbeitsplatzergonomie: Operieren mit dem Roboter
Authors: Lang Michael
Published: November 2022

Am Uniklinikum Köln untersuchen Forscherinnen und Forscher aus Design und Medizin in einer gemeinsamen Studie, wie sich die Arbeitsbedingungen für Chirurginnen und Chirurgen durch den Einsatz von OP-Robotern verändern.
Vernetzte Medizingeräte: So sicher wie Onlinebanking
Authors: Lang Michael
Published: November 2022

Im Krankenhaus der Zukunft sollen Medizingeräte herstellerunabhängig in Echtzeit und ohne die Installation weiterer Schnittstellen miteinander kommunizieren können. Der neue Standard SDC (IEEE 11073 Service-oriented Device Connectivity) bringt die nötige Sicherheit mit.
Berufliche Teilhabe: Unzeitgemäße Verbannung aus dem OP
Authors: Hohnstein Aileen
Published: November 2022

Das Mutterschutzgesetz soll unter anderem verhindern, dass Frauen berufliche Nachteile durch ihre Schwangerschaft erleiden. Aber gerade schwangeren Ärztinnen wird immer noch in vielen Fällen pauschal ein Beschäftigungsverbot ausgesprochen. Dabei ist eine sichere Weiterbeschäftigung in Kliniken möglich, wie die Positivliste des Deutschen Ärztinnenbundes zeigt.
Constanze von der Schulenburg: Das nachhaltige Gewissen von Helios
Authors: Kohrs Jens
Published: November 2022

Im April vergangenen Jahres ist Constanze von der Schulenburg bei Helios als Leiterin der Stabsstelle Nachhaltigkeit angetreten. Was hat sie schon erreicht? Und was kommt als Nächstes? Das Portrait einer Überzeugungstäterin.
Charge-induced chemical dynamics in glycine probed with time-resolved Auger electron spectroscopy
Authors: Schwickert David , Ruberti Marco , Kolorenč Přemysl , Przystawik Andreas , Skruszewicz Slawomir , Sumfleth Malte , Braune Markus , Bocklage Lars , Carretero Luis , Czwalinna Marie Kristin , Diaman Dian , Düsterer Stefan , Kuhlmann Marion , Palutke Steffen , Röhlsberger Ralf , Rönsch-Schulenburg Juliane , Toleikis Sven , Usenko Sergey , Viefhaus Jens , Vorobiov Anton , Martins Michael , Kip Detlef , Averbukh Vitali , Marangos Jon P. , Laarmann Tim
Published: November 2022

In the present contribution, we use x-rays to monitor charge-induced chemical dynamics in the photoionized amino acid glycine with femtosecond time resolution. The outgoing photoelectron leaves behind the cation in a coherent superposition of quantum mechanical eigenstates. Delayed x-ray pulses track the induced coherence through resonant x-ray absorption that induces Auger decay. Temporal modulation of the Auger electron signal correlated with specific ions is observed, which is governed by the initial electronic coherence and subsequent vibronic coupling to nuclear degrees of freedom. In the time-resolved x-ray absorption measurement, we monitor the time-frequency spectra of the resulting many-body quantum wave packets for a period of 175 fs along different reaction coordinates. Our experiment proves that by measuring specific fragments associated with the glycine dication as a function of the pump-probe delay, one can selectively probe electronic coherences at early times associated with a few distinguishable components of the broad electronic wave packet created initially by the pump pulse in the cation. The corresponding coherent superpositions formed by subsets of electronic eigenstates and evolving along parallel dynamical pathways show different phases and time periods in the range of (−0.3±0.1)π≤ϕ≤(0.1±0.2)π and 18.2−1.4+1.7≤T≤23.9−1.1+1.2 fs. Furthermore, for long delays, the data allow us to pinpoint the driving vibrational modes of chemical dynamics mediating charge-induced bond cleavage along different reaction coordinates.
Numerical simulations of the laser-driven Petschek-type magnetic reconnection
Authors: Xu Shanshan , Mei Zhixing , Zhong Jiayong , Lin Jun
Published: November 2022

This paper describes a numerical study of the magnetic reconnection between two magnetic fields of opposite polarity. The magnetic fields are created by an electric current in a coil connected to two metal disks. One of the disks is irradiated by a strong laser beam, whereby large amounts of free electrons flow toward the other disk, constituting a closed circuit for the electric current flowing through the coil. Two parallel coils are arranged to connect the two disks, and irradiation of the laser beam on one disk results in parallel electric currents in the two coils, inducing two magnetic fields of opposite polarity in the region between them. The magnetic reconnection that occurs in this region is three-dimensional. This three-dimensional magnetic reconnection is investigated via magnetohydrodynamic numerical simulations. The characteristics of the Petschek-type magnetic reconnection are observed for the first time in such numerical simulations of magnetic reconnection. Changes in the shape of the magnetic field lines form the boundary of the dissipation region and the outflow region. Moreover, the thermal plasma generated by reconnection is strongly confined to the region where the reconnecting current sheet and the slow-mode shock are located, and no leaks of thermal plasma are observed. Comparisons with existing laboratory experiment results confirm that our numerical simulations reproduce the experimental outcomes and provide reasonable explanations for the results observed in laboratories.
Electrical and optical characterization of multi-hollow surface dielectric barrier discharge in configuration with the air-exposed electrode
Authors: Cimerman Richard , Maťaš Emanuel , Sárený Matej , Hensel Karol
Published: November 2022

In this paper, multi-hollow surface dielectric barrier discharge generated by a perforated ceramic substrate in a configuration with the air-exposed electrode was investigated. The electrical characteristics (discharge power, peak, and average amplitude of current pulses) and optical characteristics (emission intensity) of the discharge were evaluated under various conditions of applied voltage (peak voltage 3–6 kV, frequency 200–2000 Hz), air flow rate (0.5–2.4 L/min), and air relative humidity (0%–80%). Temperature of ceramic substrate was also monitored. Statistical analysis of current pulses was also performed, and histograms of amplitudes of current pulses were calculated. The results showed that discharge characteristics strictly depend on given working conditions. The analysis of current pulses showed opposite trends in average overall number of positive and negative pulses with an increase of discharge power: number of positive current pulses gradually increased, while number of negative current pulses slightly decreased. The highest peak currents were found at 4 kV (1.8 W). With further increase of peak voltage, peak current decreased and beginning of detection of current pulses upon a rising (declining) slope of applied voltage was slightly shifted toward earlier times. At the highest applied peak voltage, pulses appeared even before polarity of applied voltage reversed. Therefore, we suppose that a residual charge accumulated on dielectric surface plays a crucial role in characteristics of the current pulses. Significant influence on current pulses and discharge emission intensity was also found with a change of air relative humidity, while the effect of air flow rate was found weaker.
Radiation effects in ultra-thin GaAs solar cells
Authors: Barthel A. , Sayre L. , Kusch G. , Oliver R. A. , Hirst L. C.
Published: November 2022

Ultra-thin solar cells are of significant interest for use in space due to their intrinsic radiation tolerance, which may allow them to be used in particularly harsh radiation environments, where thicker cells would degrade rapidly and enable reduction in cover glass thickness to reduce launch mass. In this study, devices with an 80 nm GaAs absorber layer were irradiated with 3 MeV protons. It is shown that integrated light management in these ultra-thin devices offers enhanced efficiency, in addition to extended lifetime through radiation resilience. Time-resolved cathodoluminescence is employed to map the introduction of radiation-induced defects with increasing proton fluence and characterize a decrease in carrier lifetime from 198 ± 5 ps pre-radiation to 6.2±0.6 ps, after irradiation to 2×1014 cm−2 fluence. Despite the substantial reduction in carrier lifetime, short-circuit current does not degrade up to a proton fluence of 1 × 1015 cm−2, beyond which a collapse in short-circuit current is observed. This exposure correlates with the point at which the carrier lifetime, extrapolated from cathodoluminescence, becomes comparable to the transit time for carriers to cross the ultra-thin device. Variation in current–voltage behavior with carrier lifetime and fluence shows that the recombination statistics are similar to those of a Shockley–Read–Hall single deep-level trap model, but that bimolecular recombination does not fully describe the observed behavior. An implication of these highly radiation tolerant cells for space power systems is shown to offer significant savings in cover glass mass, compared with a thicker cell.
Intermittent regimes as a synchronization phenomenon in two sets of nonlinear chemical oscillators
Authors: Saavedra Martín , Pérez-Mercader Juan , Muñuzuri Alberto P.
Published: November 2022

Systems of nonlinear chemical oscillators can exhibit a large diversity of non-trivial states depending on the parameters that characterize them. Among these, a synchronization phenomenon is of special interest due to its direct link with chemical and biological processes in nature. We carry out numerical experiments for two different sets of chemical oscillators with different properties and immersed in a Belousov–Zhabotinsky solution. We document the emergence of different states of synchronization that depend on the parameters characterizing the solution. We also show that, in the interface regions, this system generates a stable dynamics of intermittency between the different synchronization states where interesting phenomena, such as the “devil's staircase,” emerge. In general, the added complexity introduced with the additional set of oscillators results in more complex non-trivial synchronization states.
Numerical investigation of the effect of tracheostomy on flow and particle transport characteristics in human airways
Authors: Tran Tam Minh , Huh Sungchul , Kim Sanghun , Cui Xinguang , Choi Sanghun
Published: November 2022

Tracheostomy is a typical surgical procedure that has been widely practiced to address airway-related difficulties, such as airway obstruction or chronic conditions, that require long-term supportive ventilation. However, it may result in symptoms that detrimental to respiratory system. Computational fluid dynamics (CFD) is a noninvasive and efficient approach for observing the effects of tracheostomy. In this study, we introduced a CFD framework that can reveal the effects of tracheostomy tube insertion based on a comparison with the airflow of a normal airways. An automatic transformation method was developed using a patient's anatomical information to combine subject-specific airways with an artificial tracheostomy tube geometry and an idealized upper airway geometry for later comparison of characteristics of airflow and particle transport. The CFD scheme used for flow simulation in lungs was employed to achieve the behaviors of airflow. The tracheostomy tube generates a jet flow, resulting in twice greater wall shear stress (WSS) and 30 times greater viscous dissipation in the trachea compared to normal airway. The tracheostomized airway induces an intense turbulent jet, which enhances chaotic motion of the particles therein and allows particles to deposit more frequently on the surface. Subsequently, an increase in particle deposition is observed on the central airway's surface. The variation of pressure between inspiration and expiration phase was twice greater and the airflow resistance was also significantly higher compared to normal airway, implying the greater work of breathing. The novel framework could evaluate the efficiency and potential complications in performing tracheostomy beforehand by observing airflow behaviors.
Perspective on oxide-based three-terminal artificial synapses in physical neural networks
Authors: Chen Kuan-Ting , Chen Jen-Sue
Published: November 2022

The physical implementation of artificial neural networks, also known as “neuromorphic engineering” as advocated by Carver Mead in the late 1980s, has become urgent because of the increasing demand on massive and unstructured data processing. complementary metal-oxide-semiconductor-based hardware suffers from high power consumption due to the von Neumann bottleneck; therefore, alternative hardware architectures and devices meeting the energy efficiency requirements are being extensively investigated for neuromorphic computing. Among the emerging neuromorphic electronics, oxide-based three-terminal artificial synapses merit the features of scalability and compatibility with the silicon technology as well as the concurrent signal transmitting-and-learning. In this Perspective, we survey four types of three-terminal artificial synapses classified by their operation mechanisms, including the oxide electrolyte-gated transistor, ion-doped oxide electrolyte-gated transistor, ferroelectric-gated transistor, and charge trapping-gated transistor. The synaptic functions mimicked by these devices are analyzed based on the tunability of the channel conductance correlated with the charge relocation and polarization in gate dielectrics. Finally, the opportunities and challenges of implementing oxide-based three-terminal artificial synapses in physical neural networks are delineated for future prospects.
Ideal simple shear strengths of two HfNbTaTi-based quinary refractory multi-principal element alloys
Authors: Xu Shuozhi , Jian Wu-Rong , Beyerlein Irene J.
Published: November 2022

Atomistic simulations are employed to investigate chemical short-range ordering in two body-centered cubic refractory multi-principal element alloys, HfMoNbTaTi and HfNbTaTiZr, and its influence on their ideal simple shear strengths. Both the alias and affine shear strengths are analyzed on the {110} and {112} planes in the two opposing 111 directions. In both quinary alloys, local ordering of NbNb, TaTa, HfNb, HfTa, and NbTa is preferred as the annealing temperature decreases from 900 to 300 K. The pair that achieves the highest degree of local ordering is TiTi in HfMoNbTaTi and HfTi in HfNbTaTiZr. Subject to the affine shear, these alloys yield by first phase transformation at the most likely pairs followed by deformation twinning at those sites.
Characterizing coherences in chemical dynamics with attosecond time-resolved x-ray absorption spectroscopy
Authors: Kobayashi Yuki , Leone Stephen R.
Published: November 2022

Coherence can drive wave-like motion of electrons and nuclei in photoexcited systems, which can yield fast and efficient ways to exert materials’ functionalities beyond the thermodynamic limit. The search for coherent phenomena has been a central topic in chemical physics although their direct characterization is often elusive. Here, we highlight recent advances in time-resolved x-ray absorption spectroscopy (tr-XAS) to investigate coherent phenomena, especially those that utilize the eminent light source of isolated attosecond pulses. The unparalleled time and state sensitivities of tr-XAS in tandem with the unique element specificity render the method suitable to study valence electronic dynamics in a wide variety of materials. The latest studies have demonstrated the capabilities of tr-XAS to characterize coupled electronic–structural coherence in small molecules and coherent light–matter interactions of core-excited excitons in solids. We address current opportunities and challenges in the exploration of coherent phenomena, with potential applications for energy- and bio-related systems, potential crossings, strongly driven solids, and quantum materials. With the ongoing developments in both theory and light sources, tr-XAS holds great promise for revealing the role of coherences in chemical dynamics.
Overcoming metal-rich surface chemistry limitations of ScAlN for high electrical performance heterostructures
Authors: Engel Zachary , Motoki Keisuke , Matthews Christopher M. , Doolittle W. Alan
Published: November 2022

While metal-rich ScAlN epitaxy has traditionally led to mixed phase films by controlling the surface chemistry with transient metal doses utilizing a pulsed method of molecular beam epitaxy, phase-pure, metal-rich epitaxy of ScAlN was demonstrated, showing improved structural and electrical characteristics. The effects of substrate temperature and III/V ratio were studied, and an x-ray diffraction figure of merit and surface roughness as low as 225 arcsec and 0.68 nm, respectively, were demonstrated. A significant catalytic effect is observed with the use of Sc in metal-rich conditions, resulting in varied growth rates with substrate temperature and Sc surface coverage. This catalytic effect results in complications when selecting synthesis conditions and for in situ monitoring and can be accounted for improved phase purity. The variation of growth rates with Sc surface coverage introduces non-linearities to the transient initiation stage of growth but also introduces a feedback stabilization of the surface chemistry. Accounting for these complexities, a Sc0.2Al0.8N high electron mobility transistor (HEMT) heterostructure is demonstrated with a sheet resistance of 152 Ω/□, a mobility of 700 cm2/Vs, and a sheet charge of 5.9 × 1013 cm−2.
Direction-reversible asymmetric transmission with tunable chiral metamaterial
Authors: Dong Shufang , Hu Qi , Yang Weixu , Qu Kai , Chen Ke , Jiang Tian , Feng Yijun
Published: November 2022

The asymmetric transmission of electromagnetic waves can be flexibly manipulated by chiral metamaterials hybridized with tunable materials or active components. Here, we propose the concept of a direction-reversible tunable asymmetric transmission effect realized by chiral metamaterials. As the proof-of-concept, twisted metallic meta-sheets consisting of split-ring resonators incorporated with active diodes is designed for linearly polarized operation in the microwave region. The direction of asymmetric transmission depending on the working states of the loaded diodes can be switched by the external bias voltage in real-time. At the same time, the reconfigurable metamaterial also shows ability to control the polarization of the transmitted wave. Both the simulation and experimental results demonstrate that this direction-reversible chiral metamaterial can dynamically adjust the propagating direction of waves, showing potential uses for full-space wave manipulation and versatile modulation devices.
Zonal flow generation by small-scale drift-ion-acoustic waves in electron–positron–ion plasmas
Authors: Javaid I. , Kahlon L. Z. , Shah H. A. , Kaladze T. D.
Published: November 2022

The generation of zonal flows by small-scale coupled drift-ion-acoustic waves is investigated. The problem is analyzed in magnetized electron–positron–ion plasmas by the system of the generalized Hasegawa–Mima equation and the equation of parallel motion of ions. It is concluded that the inclusion of positrons enhances zonal flow growth rates.
Bullseye focusing of cylindrical waves at a liquid–solid interface
Authors: Gutiérrez-Hernández Ulisses J. , Reese Hendrik , Ohl Claus-Dieter , Quinto-Su Pedro A.
Published: November 2022

Two pairs of converging and superimposing shock and Rayleigh waves are generated on a glass substrate by focusing laser pulses on two concentric rings in a bullseye configuration (67 and 96 μm radii). We experimentally study the threshold for the substrate damage as a function of the number of repetitions and the delay (0–20 ns). The bullseye focusing experiments are compared to a single focusing ring. Additionally, fluid–structure interaction simulations using a volume-of-fluid framework are utilized to estimate the stresses. The lowest number of repetitions to attain surface damage is found for constructive superposition of the Rayleigh waves, i.e., here for a delay of 10 ns. The observed damage is consistent with the simulations where the largest positive stresses (∼5.6 GPa) are achieved for bullseye focusing with Δt=10 ns followed by Δt=20 ns, which corresponds to a simultaneous shock wave focusing. In all these cases, the positive stresses are followed (a few nanoseconds later) by the negative stresses that can reach ∼−6.4 GPa.
Numerical study on the hydrodynamic performance of an unconstrained carangiform swimmer
Authors: Wu Buchen , Shu Chang , Lee HsuChew , Wan Minping
Published: November 2022

Undulations are ubiquitous in natural swimmer propulsion, propelling in omni-direction. In the present work, the hydrodynamic performance of an unconstrained carangiform swimmer in the absence of a free stream is numerically investigated at different Reynolds numbers. Propulsive speed is found to increase with an increase in undulatory frequency, wavelength, and Reynolds number. The passive lateral oscillating amplitude is closely related to the wavelength and kinematic viscosity, but insensitive to the undulatory frequency. The propulsive mechanisms for the variation of the propulsive speed are revealed by the vortical structures and the time-averaged velocity field. Scaling relationships are investigated, and we found that the effects of the wavelength on the propulsive performance cannot be neglected at high Reynolds number, i.e., Reref≥1000, and the scaling relationship between the flapping Reynolds number and the propulsive Reynolds number is refined with the wavelength adopted as the characteristic length, which generalizes the previous scaling law proposed by Gazzola et al. [“Scaling macroscopic aquatic locomotion,” Nat. Phys. 10, 758–761 (2014).] In addition, the scaling relationships related to the power consumption, the cost of transport, the Strouhal number, and the passive lateral oscillating amplitude are revealed. These results are crucial in furthering our understanding of carangiform's self-propulsion and will aid the development of advanced bio-inspired propulsors.
Derivation and implementation of the optical rotation tensor for chiral crystals
Authors: Balduf Ty , Caricato Marco
Published: November 2022

This paper reports the derivation and implementation of the electric dipole-magnetic dipole and electric dipole-electric quadrupole polarizability tensors at the density functional theory level with periodic boundary conditions (DFT-PBC). These tensors are combined to evaluate the Buckingham/Dunn tensor that describes the optical rotation (OR) in oriented chiral systems. We describe several aspects of the derivation of the equations and present test calculations that verify the correctness of the tensor formulation and their implementation. The results show that the full OR tensor is completely origin invariant as for molecules and that PBC calculations match molecular cluster calculations on 1D chains. A preliminary investigation on the choice of density functional, basis set, and gauge indicates a similar dependence as for molecules: the functional is the primary factor that determines the OR magnitude, followed by the basis set and to a much smaller extent the choice of gauge. However, diffuse functions may be problematic for PBC calculations even if they are necessary for the molecular case. A comparison with experimental data of OR for the tartaric acid crystal shows reasonable agreement given the level of theory employed. The development presented in this paper offers the opportunity to simulate the OR of chiral crystalline materials with general-purpose DFT-PBC methods, which, in turn, may help to understand the role of intermolecular interactions on this sensitive electronic property.
Interpersonal-function topoi in Chinese central government’s work report (2020) as epidemic (counter-)crisis discourse
Authors: Wang Jiayu , Yang Mingfeng
Published: November 2022

Using Systemic Functional Grammar and conceptual framework in the argumentation-oriented approach to discourse, this study analyzes Chinese central government’s “ Report on the Work of the Government” in 2020 (henceforth the Report) to explore the “interpersonal-function topoi” in the political discourse. The Report was delivered and issued against the backdrop of the surging covid-19 epidemic. This study first calculated the frequency of mood, modality and persons in the Report. The statistics were qualitatively analyzed in relation to various topoi-imagery of the crisis vis-à-vis representing the agency-reflected in the interpersonal metafunction of the language in the Report. These topoi play a vital role in winning popular support for the Chinese central government’s anti-epidemic measures and mobilizing the widest public into actions against the covid-19 pandemic. The analysis demonstrates how the analysis of interpersonal metafunction from an argumentation-oriented perspective can shed light on dealing with crisis discourse, especially in the pandemic settings.
The effectiveness of second-person reference in enhancing reader memory in English-Chinese advertisement
translation
Authors: Cui Ying , Li Tianyun
Published: November 2022

This research aims to account for readers’ perception of second-person pronouns and to test their effectiveness
in enhancing reader memory in English-Chinese advertisement translation. We conducted an experiment in which 62 participants read
the Chinese translations of 16 previously unseen English print advertisements. Two parallel Chinese versions were prepared for the
experiment, one with second-person reference and the other without. The participants were first asked to read the translations and
indicate which version they liked better. Two weeks later, they were divided into two groups and asked to rate their memory of the
two Chinese versions. Statistical analysis shows that the ratings of the second-person version are significantly higher, which
implies that second-person reference is effective in enhancing the participants’ memory.
Toward a theory of ‘stepped-leaders’ in lightning
Authors: Lowke John J , Szili Endre J
Published: November 2022

An unresolved issue in the physics of lightning is an explanation for lightning proceeding to the ground by successive luminous steps separated by ‘dark’ times of many microseconds. There is also no explanation of the structure of the dark column connecting the streamer step with the cloud that can be km in length, is electrically conducting, yet has a very low sustaining electric field. It is proposed that these two processes can be explained by the accumulation of singlet delta metastable oxygen molecules excited in the corona pulses of lightning. The step time is necessary for the excitation of large metastable densities to produce significant metastable detachment of electrons from negative ions. The detached electrons form a highly conducting step, initially luminous, that causes a redistribution of electric fields and an increase in the potential and electric fields at the end of the step to make possible a further step by ionization. These features are supported by calculations of densities of electrons, positive ions, negative ions and singlet delta metastable oxygen molecules for the first 7 μs of a discharge chosen to be initiated by a 50 cm sphere of charged hail particles. The calculated corona streamers produce metastable densities of 1017 cm−3 near the corona source. These metastables, by electron detachment, produce a conducting cylinder 10 m long with a radius of 1 cm and an electron density ∼1012 cm−3 that is attributed to being the first step and a lightning ‘leader’. These conducting regions develop within them very low electric fields. Successive steps are likely to combine to form the long conductive columns of lightning that exist before the return stroke. Electron densities in the leader and the column are an equilibrium between electron production by metastable detachment and electron loss by attachment to neutral oxygen molecules, requiring no electric field.
Uncertainty and sensitivity analyses for the reduction factor of sheltering for radiation exposures
Authors: Hirouchi Jun , Takahara Shogo , Komagamine Hiroshi
Published: November 2022

Sheltering is one of the countermeasures used to mitigate radiation exposure during nuclear power plant accidents. The effectiveness of sheltering for inhalation exposure is often expressed by the reduction factor, which is defined as the ratio of the indoor to the outdoor cumulative radioactivity concentrations or doses. The indoor concentration is mainly controlled by the air exchange rate, penetration factor, and indoor deposition rate. Meanwhile, the air exchange rate depends on surrounding environmental conditions: the wind speed, leakage area normalised by the floor area of the house, and gross building coverage ratio. In this study, the ranges of the uncertainty of the reduction factors for particles and iodine in reactive gas form were investigated under various environmental conditions, and sensitivity analyses were conducted to understand the parameter with the most influence on the uncertainty of the reduction factor. From the results of the uncertainty analyses, the calculated reduction factor was highly variable depending on the environmental condition and the airtightness of the houses. The median and 95th percentile of the reduction factors for the older houses were 0.5 and 0.9 for particles and 0.07 and 0.4 for iodine in reactive gas form, respectively and these ranges were smaller for newer houses. From the results of the sensitivity analyses, the wind speed was the most influential parameter determining the reduction factor. Additionally, the wind speed was less influential for the reduction factor in newer houses.
A variable-measurement-space-based method for improving the measurement accuracy of AACMMs
Authors: Wang Wen , Liang Qianqian , Sun Jiahuan , Yang He , Lu Keqing , Wang Chuanyong , Chen Zhanfeng , Song Meng
Published: November 2022

Articulated arm coordinate measuring machines (AACMMs) are usually used to measure mechanical parts of different sizes in practical applications. When the size of parts is smaller than that of the AACMM, a redundant measurement space of the measuring machine is generated, resulting in reduced measurement accuracy of the AACMM. Moreover, due to the series structure of the AACMM, the joint errors would be propagated with the increasing length of the bar, which could amplify the measurement error. Therefore, on the premise of ensuring the measurement space required by the measured parts, this work proposes a new method based on variable measurement space, i.e. locking some movable joints of the AACMM, to improve the measurement accuracy of the AACMM for small mechanical parts. The measurement accuracy of the AACMM is examined under various measurement spaces. Firstly, the Monte Carlo method is used to simulate the measurement space of the AACMM with one or more joints locked. Then, the spatial error of the AACMM and the multipoint calibration with joint locked are simulated and discussed in detail. Finally, the feasibility and effectiveness of the proposed variable-measurement-space method are verified by the standard single-point cone experiments. The results show that the measurement accuracy of the AACMM is substantially improved under three kinds of strategies, i.e. locking joint 1, joint 2, and joint 3, respectively.
Research on feature extraction and separation of mechanical multiple faults based on adaptive variational mode decomposition and comprehensive impact coefficient
Authors: Zhang Wei , Li Junxia , Li Tengyu , Ge Shuangchao , Wu Lei
Published: November 2022

Because it is difficult to extract multiple fault features from mechanical equipment under the interference of background noise and the parameters used in variational mode decomposition (VMD) must be determined in advance, a multiple fault separation method based on adaptive variational mode decomposition (AVMD) is proposed in this research to address these issues. Firstly, a novel index, known as the comprehensive impact coefficient (CIC), is established to properly identify the signal’s fault features. Thereafter, the fitness function of the sparrow search algorithm is developed based on the CIC, and the VMD parameters selection problem is solved. Finally, the decomposed modal components are subjected to envelop demodulation analysis, and the failure type of the bearing is assessed through the envelope spectrum. The simulation and experimental results reveal that the AVMD method can effectively separate all single faults from multiple faults, thus accurately diagnosing bearing faults.
Tumor microenvironment targeting and regulating iron-based metal-organic framework for magnetic resonance imaging guided synergetic therapy of doxorubicin and hydroxyl radicals
Authors: He Le , He Yuting , Chi Bin , Xu Mingyue , Song Qian , Yang Tingting , Li Ling , Wang Jing
Published: November 2022

Fe3+ and 2-methylimidazole were selected to prepare tumor microenvironment targeted and regulated multifunctional drug carrier Fe-MOFs. The fact that Doxorubicin hydrochloride (DOX·HCl) release climbed 70% from 25% upon regulating the pH from 7.4 to 5.8 proved the pH responsive drug release of Fe-MOFs. Hydroxyl radicals (·OH) analysis proved that Fe-MOFs only generated hydroxyl radicals at pH 5.8, and dissolved oxygen performance showed the O2 was produced during the process, which was expected to regulate hypoxia in tumor cells to increase anticancer effect. Cell viability experiments proved the selectivity of Fe-MOFs and the excellent performance of synergy therapy of DOX·HCl and hydroxyl radicals. In vivo magnetic resonance imaging experiments demonstrated excellent performance of positive images. All experiments showed that Fe-MOFs can be used for image-guided collaborative treatment to improve treatment efficiency and reduce side effects.
Inhibition of parametric decay in heating microwave beams during fluctuations of the density profile in the edge island of Wendelstein 7-X
Authors: Tancetti A , Nielsen S K , Rasmussen J , Moseev D , Stange T , Marsen S , Vecséi M , Killer C , Wurden G A , Jensen T , Stejner M , Anda G , Dunai D , Zoletnik S , Rahbarnia K , Brandt C , Thomsen H , Hirsch M , Hoefel U , Chaudhary N , Winters V , Kornejew P , Harris J , Laqua H P
Published: November 2022

Experimental evidence of parametric decay instability (PDI) is observed in the Wendelstein 7-X stellarator, when high-power microwave beams cross a stationary magnetic island at the plasma edge. Here, trapping and build-up of upper hybrid waves within a density bump (measured within the island by alkali beam emission spectroscopy) is responsible for the reduction of the instability power threshold below the maximum gyrotron power. In this paper, we provide the first experimental evidence of the connection between the trapping mechanism in the island density bump and excitation of PDI-related signals. We show correlations of periodic crashes in the PDI-related signals with quasi-continuous fluctuations at the plasma edge, which, additionally, cause a flattening of the density profile in the island. We demonstrate that flattening of the experimental density profiles can suppress the trapping mechanism and inhibit the low-threshold PDI. PDI on the edge island could alter the power deposition profile and reduce the efficiency of the electron cyclotron resonance heating system, simultaneously posing a serious threat to the optimal operation of microwave-based diagnostics and plasma-facing components.
Microstructure and substrate dependent enhanced critical current density in Pb-substituted Bi-based high temperature superconducting thin films
Authors: V Gayathri , A T Sathyanarayana , K Vinod , Geetha Kumary T , Mani Awadhesh
Published: November 2022

A comparative study was carried out using magnetization measurements to understand the diamagnetic response of the superconducting thin films of Bi1.75Pb0.25Sr2Ca2Cu3O10±δ
grown on two different substrates. The film grown on SrTiO3 substrate was found to exhibit enhanced superconducting properties than the film grown on LaAlO3 substrate. The strengthening of the intergrain coupling by the growth of the larger grains with better grain connectivity and enhanced pinning mechanism yielded a critical current density as high as ∼4.8 × 105 Acm−2 in the film grown on SrTiO3 substrate. An enhancement in the value of the critical current density with the decrease in the dimensionality of the sample on account of a change in the microstructure was observed. As revealed from the AC susceptibility measurements, the metallic nature of the weak links conveys that the weak links are essentially the coexisting secondary phases in these films. Furthermore, the paramagnetic Meissner effect was observed in these films, which can be explained within the realm of the flux compression models.
Cherenkov radiation from stars constrains hybrid MOND dark matter models
Authors: Mistele Tobias
Published: November 2022

We propose a new method to constrain alternative models for dark matter with observations.
Specifically, we consider hybrid models
in which cold dark matter (CDM) phenomena on cosmological scales
and Modified Newtonian Dynamics (MOND) phenomena on galactic scales share a common origin.
Various such models were recently proposed.
They typically contain a mode that is directly coupled to matter (for MOND)
and has a non-relativistic sound speed (for CDM).
This allows even non-relativistic objects like stars to lose energy through Cherenkov radiation.
This is unusual.
Most modified gravity models have a relativistic sound speed,
so that only high-energy cosmic rays emit Cherenkov radiation.
We discuss the consequences of this Cherenkov radiation from stars.