bluuebunny/crossref_metadata_2025 huggingface dataset:
Qualitätstransparenz in der stationären Krankenhausversorgung der Schweiz
Authors: Ahlen Christine von , Moser Dominik , Geissler Alexander
Published: June 2021

Qualitätstransparenz ist eine entscheidende Grundlage für den Abbau von Informationsasymmetrien im Gesundheitswesen. Doch welche Informationen zur stationären, akutsomatischen Versorgung sind in der Schweiz vorhanden, wie können diese genutzt werden und welche Folgen ergeben sich daraus? Für diese Fragestellungen wird ein Review des Datenangebots vorgenommen, systematisch aufbereitet sowie Stärken und Schwächen aufgezeigt. Auf dieser Grundlage sowie internationalen Vergleichen folgen gesundheitspolitische Empfehlungen für eine Verbesserung der aktuellen Bedingungen. Die Studie zeigt auf, dass Qualitätstransparenz in der Schweiz trotz des bereits im Jahr 2011 vereinbarten nationalen Qualitätsvertrags nur begrenzt gegeben ist. Dies erschwert die Stärkung eines Qualitätswettbewerbs, die informierte Entscheidung über die Krankenhauswahl von Patienten sowie das selektive Kontrahieren. Eine Weiterentwicklung der in der Schweiz verfügbaren Daten und Messinstrumente in Krankenhäusern ist daher angezeigt und bedarf einer priorisierten Umsetzung.
Catalyst- and Additive-Free Synthesis of Fluoroalkoxyquinolines
Authors: Sharma Upendra , Dhiman Ankit Kumar , Kumar Rohit
Published: June 2021

A nucleophilic substitution approach has been developed for the synthesis of C4 fluoroalkoxyquinolines from 4-haloquinolines by utilizing hexafluoro-2-propanol and trifluoroethanol as nucleophiles. The method is also applicable for 2-chloroquinolines, 1-chloroisoquinoline, and 2-chlorobenzimidazole. Control experiments revealed that substitution occurs only at the C2 and C4 positions of quinolines.
A Practical and Efficient Conversion of Luteolin into Luteoloside
Authors: Palmieri Alessandro , Bassetti Benedetta , Ballini Roberto , Ciceri Daniele , Allegrini Pietro
Published: June 2021

A new practical and efficient preparation of the flavonoid luteoloside is reported in an excellent overall yield of 40% via a four-step synthetic approach.
Visible-Light-Mediated Photocatalytic Oxidative C–C Bond Cleavage of Geminal Diazides: An Approach to Oxamates
Authors: Sharada Duddu S. , Katta Narenderreddy , Murugan Arumugavel , Sharma Sonika
Published: June 2021

Photoredox catalysis has received great attention in both academia and industry and remarkable progress has been made over the past decade. Now, it has been shown that a visible-light-mediated oxidative C–C bond cleavage of geminal diazides can be induced by organic dye catalysis for the synthesis of oxamates. A mechanistic study, confirmed by control experiments, indicates that this proceeds through single-electron transfer (SET). This methodology can be applied to convert a wide array of geminal diazides into oxamates.
Predicting the Health-related Quality of Life in Patients Following Traumatic Brain Injury
Authors: Tunthanathip Thara , Oearsakul Thakul , Tanvejsilp Pimwara , Sae-heng Sakchai , Kaewborisutsakul Anukoon , Madteng Suphavadee , Inkate Srirat
Published: June 2021

Background Traumatic brain injury (TBI) commonly causes death and disability that can result in productivity loss and economic burden. The health-related quality of life (HRQoL) has been measured in patients suffering from TBI, both in clinical and socioeconomic perspectives. The study aimed to assess the HRQoL in patients following TBI using the European quality of life measure-5 domain-5 level (EQ-5D-5L) questionnaire and develop models for predicting the EQ-5D-5L index score in patients with TBI.

Method A cross-sectional study was performed with 193 TBI patients who had completed the EQ-5D-5L questionnaire. The clinical characteristics, Glasgow coma scale (GCS) score, treatment, and Glasgow outcome scale (GOS) were collected. The total data was divided into training data (80%) and testing data (20%); hence, the factors affecting the EQ-5D-5L index scores were used to develop the predictive model with linear and nonlinear regression. The performances of the predictive models were estimated with the adjusted coefficient of determination (R2) and the root mean square error (RMSE).

Results A good recovery was found at 96.4%, while 2.1% displayed an unfavorable outcome. Moreover, the mean EQ-5D-5L index scores were 0.91558 (standard deviation [SD] 1.09639). GCS score, pupillary light reflex, surgery, and GOS score significantly correlated with the HRQoL scores. The multiple linear regression model had a high adjusted R2 of 0.6971 and a low RMSE of 0.06701, while the polynomial regression developed a nonlinear model that had the highest adjusted R2 of 0.6843 and the lowest RMSE of 0.06748.

Conclusions A strong positive correlation between the physician-based outcome as GOS and HRQoL was observed. Furthermore, both the linear and nonlinear regression models were acceptable approaches to predict the HRQoL of patients after TBI. There would be limitations for estimating the HRQoL in unconscious or intubated patients. The HRQoL obtained from the predictive models would be an alternative method to resolve this problem.
Color discriminability makes over-specification efficient: Theoretical analysis and empirical evidence
Authors: Rubio-Fernandez Paula
Published: June 2021

A psychophysical analysis of referential communication establishes a causal link between a visual stimulus and a speaker’s perception of this stimulus, and between the speaker’s internal representation and their reference production. Here, I argue that, in addition to visual perception and language, social cognition plays an integral part in this complex process, as it enables successful speaker-listener coordination. This pragmatic analysis of referential communication tries to explain the redundant use of color adjectives. It is well documented that people use color words when it is not necessary to identify the referent; for instance, they may refer to “the blue star” in a display of shapes with a single star. This type of redundancy challenges influential work from cognitive science and philosophy of language, suggesting that human communication is fundamentally efficient. Here, I explain these seemingly contradictory findings by confirming the visual efficiency hypothesis: redundant color words can facilitate the listener’s visual search for a referent, despite making the description unnecessarily long. Participants’ eye movements revealed that they were faster to find “the blue star” than “the star” in a display of shapes with only one star. A language production experiment further revealed that speakers are highly sensitive to a target’s discriminability, systematically reducing their use of redundant color adjectives as the color of the target became more pervasive in a display. It is concluded that a referential expression’s efficiency should be based not only on its informational value, but also on its discriminatory value, which means that redundant color words can be more efficient than shorter descriptions.
Perspective on remote photonic bio-sensing and diagnosis
Authors: Ozana Nisan , Zalevsky Zeev
Published: June 2021

In this Perspective Letter, we discuss the field of remote photonic bio-sensing and diagnosis while focusing on sensing involving spatial analysis of temporally varied defocused secondary speckle patterns. Collecting secondary speckle patterns that were back-reflected from an inspected tissue while properly defocusing the imaging lens allows us to measure nano-vibrations occurring in the tissue. The nano-vibration signal can serve as the common denominator for simultaneous estimation of many bio-medical parameters related to vital bio-signs, hematology, and hemodynamics. This can provide a powerful tool for comprehensive medical diagnosis.
High-pressure behavior of heteroepitaxial core–shell particles made of Prussian blue analogs
Authors: Maurin Isabelle , Itoi Miho , Cain John M. , Talham Daniel R. , Gacoin Thierry , Boukheddaden Kamel , Itié Jean-Paul
Published: June 2021

We report the compressibility of two Prussian blue analogs (PBAs) under hydrostatic pressure, one with small and one with a relatively large cubic unit cell among PBAs, and investigate the modification of their elastic properties when the two lattices are coupled within a heteroepitaxial core–shell structure. Bulk modulus (K0) values are derived from x-ray powder diffraction experiments using a diamond anvil cell with silicone oil as a pressure-transmitting medium. The pressure–volume curves fitted to Murnaghan equations of states show that K0 inversely scales with the crystal packing for the rubidium cobalt hexacyanoferrate and rubidium nickel hexacyanochromate samples (K0 ∼ 29 GPa for Co-Fe PBA, a0 = 9.95 Å and ∼20 GPa for Ni-Cr PBA, a0 = 10.48 Å with a0 being the lattice constant at ambient pressure). The two single-phase samples undergo a cubic-to-rhombohedral phase transition above ∼0.8 GPa, which correlates fairly well with the build-up of nonhydrostatic pressure contributions in the cell. Within the core–shell structure, the volume change observed for the core scales with that of the shell because of the configuration close to the case of a solid pressure-transmitting medium. The Ni-Cr PBA shell layer exhibits an increased rhombohedral distortion with respect to the single-phase reference possibly associated with shearing at the core–shell interface. Its bulk modulus is not significantly modified with respect to that of the single-phase sample despite the presence of defects associated with the growth mode, whereas the P-V curve of the core suggests a stiffening of the Co-Fe PBA lattice.
Evolution of waves in a horizontal pipe propagating on a surface of a liquid film sheared by gas
Authors: Kumar Krishanu , Fershtman Adam , Barnea Dvora , Shemer Lev
Published: June 2021

Different wavy regimes in stratified air–water pipe flow are determined for a wide range of gas and liquid flow rates in a 10 m long horizontal pipe with a diameter of 24 mm. Three sub-regions of wavy stratified flow are identified: ripples, roll waves, and pre-annular wavy flow. Statistical parameters, such as local mean film thickness and its higher moments (root-mean-square, skewness, excess kurtosis) as well as wave characteristics (mean heights and wave height distributions, lengths, propagation velocities, etc.), are measured and analyzed. It is demonstrated that ripples are essentially linear waves and their propagation velocities are described reasonably well by linear wave theory. High amplitude roll and pre-annular waves are substantially nonlinear, and their propagation velocities differ significantly from that of ripples. Transition to roll waves causes a sharp increase in higher statistical moments. Evolution of wave and statistical parameters characterizing each sub-region of stratified gas–liquid pipe flow is studied. Simplified models describing roll waves are presented; the model predictions are verified by experiments.
Classical nucleation theory of ice nucleation: Second-order corrections to thermodynamic parameters
Authors: Wang Chaohong , Wu Jianyang , Wang Hao , Zhang Zhisen
Published: June 2021

Accurately estimating the nucleation rate is crucial in studying ice nucleation and ice-promoting and anti-freeze strategies. In classical nucleation theory, estimates of the ice nucleation rate are very sensitive to thermodynamic parameters, such as the chemical potential difference between water and ice Δμ and the ice–water interfacial free energy γ. However, even today, there are still many contradictions and approximations when estimating these thermodynamic parameters, introducing a large uncertainty in any estimate of the ice nucleation rate. Starting from basic concepts for a general solid–liquid crystallization system, we expand the Gibbs–Thomson equation to second order and derive second-order analytical formulas for Δμ, γ, and the nucleation barrier ΔG*, which are used in molecular dynamics simulations. These formulas describe well the temperature dependence of these thermodynamic parameters. This may be a new method of estimating Δμ, γ, and ΔG*.
Focal-point approach with pair-specific cusp correction for coupled-cluster theory
Authors: Irmler Andreas , Gallo Alejandro , Grüneis Andreas
Published: June 2021

We present a basis set correction scheme for the coupled-cluster singles and doubles (CCSD) method. The scheme is based on employing frozen natural orbitals (FNOs) and diagrammatically decomposed contributions to the electronic correlation energy, which dominate the basis set incompleteness error (BSIE). As recently discussed in the work of Irmler et al. [Phys. Rev. Lett. 123, 156401 (2019)], the BSIE of the CCSD correlation energy is dominated by the second-order Møller–Plesset (MP2) perturbation energy and the particle–particle ladder term. Here, we derive a simple approximation to the BSIE of the particle–particle ladder term that effectively corresponds to a rescaled pair-specific MP2 BSIE, where the scaling factor depends on the spatially averaged correlation hole depth of the coupled-cluster and first-order pair wavefunctions. The evaluation of the derived expressions is simple to implement in any existing code. We demonstrate the effectiveness of the method for the uniform electron gas. Furthermore, we apply the method to coupled-cluster theory calculations of atoms and molecules using FNOs. Employing the proposed correction and an increasing number of FNOs per occupied orbital, we demonstrate for a test set that rapidly convergent closed and open-shell reaction energies, atomization energies, electron affinities, and ionization potentials can be obtained. Moreover, we show that a similarly excellent trade-off between required virtual orbital basis set size and remaining BSIEs can be achieved for the perturbative triples contribution to the CCSD(T) energy employing FNOs and the (T*) approximation.
Computational discovery of stable and metastable ternary oxynitrides
Authors: Sharan Abhishek , Lany Stephan
Published: June 2021

Materials design from first principles enables exploration of uncharted chemical spaces. Extensive computational searches have been performed for mixed-cation ternary compounds, but mixed-anion systems are gaining increased interest as well. Central to computational discovery is the crystal structure prediction, where the trade-off between reliance on prototype structures and size limitations of unconstrained sampling has to be navigated. We approach this challenge by letting two complementary structure sampling approaches compete. We use the kinetically limited minimization approach for high-throughput unconstrained crystal structure prediction in smaller cells up to 21 atoms. On the other hand, ternary—and, more generally, multinary—systems often assume structures formed by atomic ordering on a lattice derived from a binary parent structure. Thus, we additionally sample atomic configurations on prototype lattices with cells up to 56 atoms. Using this approach, we searched 65 different charge-balanced oxide–nitride stoichiometries, including six known systems as the control sample. The convex hull analysis is performed both for the thermodynamic limit and for the case of synthesis with activated nitrogen sources. We identified 34 phases that are either on the convex hull or within a viable energy window for potentially metastable phases. We further performed structure sampling for “missing” binary nitrides whose energies are needed for the convex hull analysis. Among these, we discovered metastable Ce3N4 as a nitride analog of the tetravalent cerium oxide, which becomes stable under slightly activated nitrogen condition ΔμN > +0.07 eV. Given the outsize role of CeO2 in research and application, Ce3N4 is a potentially important discovery.
Effect of diffusion constant on the morphology of dendrite growth in lithium metal batteries
Authors: Jang Inhyuk , Yethiraj Arun
Published: June 2021

Lithium dendrites can lead to a short circuit and battery failure, and developing strategies for their suppression is of considerable importance. In this work, we study the growth of dendrites in a simple model system where the solvent is a continuum and the lithium ions are hard spheres that can deposit by sticking to existing spheres or the electrode surface. Using stochastic dynamics simulations, we investigate the effect of applied voltage and diffusion constant on the growth of dendrites. We find that the diffusion constant is the most significant factor, and the inhomogeneity of the electric field does not play a significant role. The growth is most pronounced when the applied voltage and diffusion constant are both low. We observe a structural change from broccoli to cauliflower shape as the diffusion constant is increased. The simulations suggest that a control of electrolyte parameters that impact lithium diffusion might be an attractive route to controlling dendrite growth.
Unintentional passivation of 4-tertbutyl pyridine for improved efficiency and decreased operational stability of perovskite solar cells
Authors: Tumen-Ulzii Ganbaatar , Auffray Morgan , Matsushima Toshinori , Adachi Chihaya
Published: June 2021

Defect-induced nonradiative recombination limits power conversion efficiency (PCE) of organic–inorganic lead halide perovskite solar cells (PSCs). Recently, molecular passivation methods using ammonium salts and Lewis bases have been gathering tremendous attention for reducing defects at perovskite film surfaces. In this work, we find that an excess amount of 4-tert-butylpyridine (4-tBP), which is used as an additive for an organic hole transport layer, passivates surface defects of perovskite films and, therefore, improves the initial performance of PSCs. In PSCs with this 4-tBP passivation, we achieve very high open circuit voltages of >1.20 V, with a corresponding voltage deficit of 0.38 V, and PCEs of >20%. However, operational stability of PSCs under continuous illumination is greatly decreased. Thus, this work reveals that the 4-tBP passivation causes a trade-off between PCE and operational stability of PSCs.
High-resolution diagnostics of GaAs wafer inhomogeneity using an optical switch within the terahertz band
Authors: Kulygin M. L. , Litovsky I. A. , Belousov V. I. , Novikov E. A. , Kalynova G. I. , Shmelev M. Y.
Published: June 2021

We study a technique for diagnostics of the loss tangent inhomogeneity in semi-insulating gallium arsenide within a frequency band of 0.3 THz and higher. The low-oversize-factor resonator of the recently developed optical switch formed by an intersection of a single-mode waveguide and a cutoff waveguide in the presence of a semiconductor is used to analyze small fragments of a movable test wafer. The obtained spatial resolution (0.1 mm2) is much higher than that of the known methods. The results of using the finite difference time domain theory for synthesis of the optimal resonator are compared with the experimental data and with the data of the reference experiment performed by the known alternative method. The intrinsic precision of the loss tangent measured by our method is about 3%. The most significant difference from the known methods is that the test wafer does not overlap the traveling mode waveguide, nor perturb an existing resonator, but creates a resonator by itself. Opportunities of increasing the precision and frequency are discussed.
Confronting interatomic force measurements
Authors: Dagdeviren Omur E.
Published: June 2021

The quantitative interatomic force measurements open a new pathway to materials characterization, surface science, and chemistry by elucidating the tip–sample interaction forces. Atomic force microscopy is the ideal platform to gauge interatomic forces between the tip and the sample. For such quantitative measurements, either the oscillation frequency or the oscillation amplitude and the phase of a vibrating cantilever are recorded as a function of the tip–sample separation. These experimental quantities are subsequently converted into the tip–sample interaction force, which can be compared with interatomic force laws to reveal the governing physical phenomena. Recently, it has been shown that the most commonly applied mathematical conversion techniques may suffer a significant deviation from the actual tip–sample interaction forces. To avoid the assessment of unphysical interatomic forces, the use of either very small (i.e., a few picometers) or very large oscillation amplitudes (i.e., a few nanometers) has been proposed. However, the use of marginal oscillation amplitudes gives rise to another problem as it lacks the feasibility due to the adverse signal-to-noise ratios. Here, we show a new mathematical conversion principle that confronts interatomic force measurements while preserving the oscillation amplitude within the experimentally achievable and favorable limits, i.e., tens of picometers. Our theoretical calculations and complementary experimental results demonstrate that the proposed technique has three major advantages over existing methodologies: (I) eliminating mathematical instabilities of the reconstruction of tip–sample interaction force, (II) enabling accurate conversion deep into the repulsive regime of tip–sample interaction force, and (III) being robust to the uncertainty of the oscillation amplitude and the measurement noise. Due to these advantages, we anticipate that our methodology will be the nucleus of a reliable evaluation of material properties with a more accurate measurement of tip–sample interaction forces.
Immiscibility in N2–H2O solids up to 140 GPa
Authors: Zhang Xiao , Wang Yu , Bykov Maxim , Bykova Elena , Chariton Stella , Prakapenka Vitali B. , Glazyrin Konstantin , Goncharov Alexander F.
Published: June 2021

Nitrogen and water are very abundant in nature; however, the way they chemically react at extreme pressure–temperature conditions is unknown. Below 6 GPa, they have been reported to form clathrate compounds. Here, we present Raman spectroscopy and x-ray diffraction studies in the H2O–N2 system at high pressures up to 140 GPa. We find that clathrates, which form locally in our diamond cell experiments above 0.3 GPa, transform into a fine grained state above 6 GPa, while there is no sign of formation of mixed compounds. We point out size effects in fine grained crystallites, which result in peculiar Raman spectra in the molecular regime, but x-ray diffraction shows no additional phase or deviation from the bulk behavior of familiar solid phases. Moreover, we find no sign of ice doping by nitrogen, even in the regimes of stability of nonmolecular nitrogen.
Numerical investigation of three-dimensional partial cavitation in a Venturi geometry
Authors: Gouin Camille , Junqueira-Junior Carlos , Goncalves Da Silva Eric , Robinet Jean-Christophe
Published: June 2021

Sheet cavitation appears in many hydraulic applications and can lead to technical issues. Some fundamental outcomes, such as, the complex topology of 3-dimensional cavitation pockets and their associated dynamics need to be carefully visited. In the paper, the dynamics of partial cavitation developing in a 3D Venturi geometry and the interaction with sidewalls are numerically investigated. The simulations are performed using a one-fluid compressible Reynolds-averaged Navier–Stokes solver associated with a nonlinear turbulence model and a void ratio transport equation model. A detailed analysis of this cavitating flow is carried out using innovative tools, such as, spectral proper orthogonal decompositions. Particular attention is paid in the study of 3D effects by comparing the numerical results obtained with sidewalls and periodic conditions. A three-dimensional dynamics of the sheet cavitation, unrelated to the presence of sidewalls, is identified and discussed.
Electron binding energies and Dyson orbitals of OnH2n+1+,0,− clusters: Double Rydberg anions, Rydberg radicals, and micro-solvated hydronium cations
Authors: Opoku Ernest , Pawłowski Filip , Ortiz Joseph Vincent
Published: June 2021

Ab initio electron propagator methods are employed to predict the vertical electron attachment energies (VEAEs) of OH3+(H2O)n clusters. The VEAEs decrease with increasing n, and the corresponding Dyson orbitals are diffused over exterior, non-hydrogen bonded protons. Clusters formed from OH3− double Rydberg anions (DRAs) and stabilized by hydrogen bonding or electrostatic interactions between ions and polar molecules are studied through calculations on OH3−(H2O)n complexes and are compared with more stable H−(H2O)n+1 isomers. Remarkable changes in the geometry of the anionic hydronium–water clusters with respect to their cationic counterparts occur. Rydberg electrons in the uncharged and anionic clusters are held near the exterior protons of the water network. For all values of n, the anion–water complex H−(H2O)n+1 is always the most stable, with large vertical electron detachment energies (VEDEs). OH3−(H2O)n DRA isomers have well separated VEDEs and may be visible in anion photoelectron spectra. Corresponding Dyson orbitals occupy regions beyond the peripheral O–H bonds and differ significantly from those obtained for the VEAEs of the cations.
Piezotronic effect in a normally off p-GaN/AlGaN/GaN HEMT toward highly sensitive pressure sensor
Authors: Nguyen Hong-Quan , Nguyen Thanh , Tanner Philip , Nguyen Tuan-Khoa , Foisal Abu Riduan Md , Fastier-Wooller Jarred , Nguyen Tuan-Hung , Phan Hoang-Phuong , Nguyen Nam-Trung , Dao Dzung Viet
Published: June 2021

We report the effect of stress or strain on the electronic characteristics of a normally off AlGaN/GaN high electron mobility transistor (HEMT) and demonstrate its role as a highly sensitive pressure sensor. We observe that the HEMT drain current exhibits a linear change of 2.5%/bar upon the application of pressure, which is translated to a strain sensitivity of 1250 ppm−1. This is the highest strain sensitivity ever reported on HEMTs and many other conventional strain sensing configurations. The relative change of drain current is largest when the gate bias is near-threshold and drain bias is slightly larger than the saturation bias. The electron sheet density and mobility changes in the AlGaN/GaN heterointerface under the applied pressure or mechanical strain are explained qualitatively. The spontaneous and piezoelectric-polarization-induced surface and interface charges in the AlGaN/GaN heterojunction can be used to develop very sensitive and robust pressure sensors. The results demonstrate a considerable potential of normally off AlGaN/GaN HEMTs for highly sensitive and reliable mechanical sensing applications with low energy consumption.
Equivalent fluid approach to modeling the acoustical properties of polydisperse heterogeneous porous composites
Authors: Núñez Gabriel , Venegas Rodolfo , Zieliński Tomasz G. , Bécot François-Xavier
Published: June 2021

This paper investigates sound propagation in polydisperse heterogeneous porous composites. The two-scale asymptotic method of homogenization is used to obtain a macroscopic description of the propagation of sound in such composites. The upscaled equations demonstrate that the studied composites can be modeled as equivalent fluids with complex-valued frequency-dependent effective parameters (i.e., dynamic viscous permeability and compressibility) as well as unravel the sound energy dissipation mechanisms involved. The upscaled theory is both exemplified by introducing analytical and hybrid models for the acoustical properties of porous composites with different geometries and constituent materials (e.g., a porous matrix with much less permeable and/or impervious inclusions with simple or complex shapes) and validated through computational experiments successfully. It is concluded that the developed theory rigorously captures the physics of acoustic wave propagation in polydisperse heterogeneous porous composites and shows that the mechanisms that contribute to the dissipation of sound energy in the composite are classical visco-thermal dissipation together with multiple pressure diffusion phenomena in the heterogeneous inclusions. The results show that the combination of two or more permeable materials with highly contrasted permeabilities can improve the acoustic absorption and transmission loss of the composite. This paper provides fundamental insights into the propagation of acoustic waves in complex composites that are expected to guide the rational design of novel acoustic materials.
Properties of stress-induced super tetragonal phase in epitaxial BiFeO3 thin film
Authors: Cao Guoping , Zhang Teng , Chu Ying-Hao , Zhu Jing , Yu Rong
Published: June 2021

Stress-induced structural phase transitions in multiferroic BiFeO3 thin films have attracted much attention for both fundamental research and promising applications in electronic devices. In this work, with the assistance of spherical aberration-corrected transmission electron microscopy, a tetragonal phase with the super large tetragonality (c/a ∼ 1.53) was found in the epitaxial BiFeO3 thin film on a LaAlO3/Si substrate. Analyses of atom positions showed that displacements of an Fe atom in this super tetragonal phase are much smaller than that in a regular tetragonal phase. First-principles calculations revealed that the structural phase transition occurs with the increasing lattice tetragonality c/a, accompanied by transitions in the atomic coordination and magnetic order.
Tuning of micelle adsorption on nanoparticles by combination of surfactants
Authors: Singh Himanshi , Aswal Vinod K.
Published: June 2021

The interaction of anionic silica nanoparticles with nonionic decaethylene glycol mono-dodecyl ether (C12E10) and ionic surfactants [both anionic sodium dodecyl sulfate (SDS) and cationic dodecyl trimethyl ammonium bromide (DTAB)] has been studied by small-angle neutron scattering and dynamic light scattering. The nonionic and cationic surfactant micelles are adsorbed on nanoparticles, whereas no adsorption of SDS surfactant micelles on nanoparticles is observed. The adsorption of C12E10 micelles provides additional steric stability to nanoparticles. However, the adsorption of cationic micelles leads to micelles-mediated fractal aggregation of nanoparticles. In the case of SDS surfactant, nanoparticles and micelles coexist in the solution. Furthermore, the adsorption behavior of surfactant micelles on nanoparticles has been tuned using a combination of nonionic and ionic surfactants. The combination of nonionic C12E10 with anionic SDS makes surfactant micelles to desorb from nanoparticles, whereas the combination of nonionic C12E10 with cationic DTAB leads to fractal aggregation of nanoparticles. The systematic transitions of micelle adsorption to desorption on nanoparticles with a C12E10–SDS mixed surfactant system and the aggregation of nanoparticles in a C12E10–DTAB mixed surfactant system as a function of ionic surfactant (SDS or DTAB) concentration have been examined. The micelles desorption from nanoparticles follows an exponential decay behavior with an increase in SDS concentration in C12E10–SDS, whereas the aggregate size shows an exponential growth with DTAB in C12E10–DTAB. The electrostatic interactions between nanoparticles and surfactant micelles are found to be dominating for tuning these transitions.
Spectral tuning of double resonant nanolaminate plasmonic nanoantennas with a fixed size
Authors: Mejia E. , Qian Y. , Safiabadi Tali S. A. , Song J. , Zhou W.
Published: June 2021

Multiresonant plasmonic nanoantennas can enhance nanolocalized multiphoton processes or enable wavelength-multiplexed nano-optic operations by supporting multiple spatially overlapped plasmonic modes. Nevertheless, current multiresonant plasmonic nanoantenna designs do not consider engineering multiresonant spectral responses with strict size and footprint constraints. Developing a strategy to engineer fixed-size nanoantennas with tunable multiresonant responses is highly desirable for maintaining controlled cellular responses at the nano-bio interface and achieving seamless integration with other nanodevices with predefined footprints. Here, we report that fixed-size tapered nanolaminate nanoantennas (TNLNAs) can achieve a wide double-resonance spectral tunability by only changing the metal-to-insulator thickness ratio (t/h). Three separate TNLNAs' samples (8/38 , 20/20, and 28/8 nm) with a nominal total height of ∼100 nm are created from a high-throughput nanofabrication technique. Specifically, we fabricated TNLNAs' samples by exploiting a nanohole array membrane from soft interference lithography as a deposition mask for electron-beam evaporation of alternating Au and SiO2 layers. Transmission and dark field scattering measurements show that TNLNAs support two distinct resonant features with t/h-dependent tunable resonant wavelengths in the range of 730–850 and 840–1050 nm, respectively. Numerical simulations reveal that (i) a bianisotropy-induced magnetoelectric response in top and bottom nanogaps due to the asymmetric tapered shape can enhance light trapping and achieve optical near-field intensity enhancements up to 1000-fold and (ii) while TNLNAs consisting of thin Au nanodisks at low t/h primarily support spatial overlap between modes with enhanced electric polarizability, TNLNAs consisting of thick Au nanodisks at high t/h support spatial overlap between modes with enhanced magnetic polarizability, evoking higher-order multipolar behaviors.
Acoustic multi-layer Helmholtz resonance metamaterials with multiple adjustable absorption peaks
Authors: Duan Haiqin , Shen Xinmin , Wang Enshuai , Yang Fei , Zhang Xiaonan , Yin Qin
Published: June 2021

The single Helmholtz resonator obtains only one absorption peak in the broad frequency range, which limits its application in reducing the noise with multiple spectra. This paper reports an acoustic multi-layer Helmholtz resonance metamaterial, which can achieve multiple absorption peaks at given low-frequency targets. Meanwhile, through adjusting structural parameters of the multi-layer Helmholtz resonator, its impedance can be altered correspondingly to realize the absorption of noise with the multi groups of specific frequencies. In this paper, in order to achieve fine absorption performance with the specific frequencies of 100 and 400 Hz for a substation noise source, the sound absorption principle of a classical Helmholtz resonator with the embedded aperture is introduced theoretically, and then two series of multi-layer Helmholtz resonance structures with different parameters are designed. Thickness of the multi-layer structure is only 1/30th of the working wavelength, and two groups of resonance peaks are generated at 100 and 400 Hz, respectively. A finite element model of the multi-layer Helmholtz resonator is constructed to simulate its absorption performance. The samples are fabricated through the 3D light-curing printing, and their sound absorption performances are detected by the standing wave method. The simulation results are in good agreement with the experimental data, and two peaks with near-perfect absorptions are achieved at the target frequencies. The multi-layer Helmholtz resonator for achievement of three groups of absorption peaks is proposed later. This work provides an effective method to design a sound absorber with multiple absorption peaks, which can promote the application of acoustic metamaterials.
Time-dependent optimized coupled-cluster method for multielectron dynamics. IV. Approximate consideration of the triple excitation amplitudes
Authors: Pathak Himadri , Sato Takeshi , Ishikawa Kenichi L.
Published: June 2021

We present a cost-effective treatment of the triple excitation amplitudes in the time-dependent optimized coupled-cluster (TD-OCC) framework called TD-OCCDT(4) for studying intense laser-driven multielectron dynamics. It considers triple excitation amplitudes correct up to the fourth-order in many-body perturbation theory and achieves a computational scaling of O(N7), with N being the number of active orbital functions. This method is applied to the electron dynamics in Ne and Ar atoms exposed to an intense near-infrared laser pulse with various intensities. We benchmark our results against the TD complete-active-space self-consistent field (TD-CASSCF), TD-OCC with double and triple excitations (TD-OCCDT), TD-OCC with double excitations (TD-OCCD), and TD Hartree–Fock (TDHF) methods to understand how this approximate scheme performs in describing nonperturbatively nonlinear phenomena, such as field-induced ionization and high-harmonic generation. We find that the TD-OCCDT(4) method performs equally well as the TD-OCCDT method, almost perfectly reproducing the results of the fully correlated TD-CASSCF with a more favorable computational scaling.
Electron overflow of AlGaN deep ultraviolet light emitting diodes
Authors: Pandey A. , Gim J. , Hovden R. , Mi Z.
Published: June 2021

We have studied the design, epitaxy, and performance characteristics of deep ultraviolet (UV) AlGaN light emitting diodes (LEDs). By combining the tunnel junction and polarization-engineered AlGaN electron blocking layer, a maximum external quantum efficiency and wall-plug efficiency of 0.35% and 0.21%, respectively, were measured for devices operating at ∼245 nm, which are over one order of magnitude higher than previously reported tunnel junction devices at this wavelength. Severe efficiency droop, however, was measured at very low current densities (∼0.25 A/cm2), which, together with the transverse magnetic (TM) polarized emission, is identified to be the primary limiting factors for the device performance. Detailed electrical and optical analysis further shows that the observed efficiency droop is largely due to an electrical effect instead of an optical phenomenon. Our studies suggest that AlGaN deep UV LEDs with efficiency comparable to InGaN blue-emitting quantum wells can be potentially achieved if issues related to electron overflow and TM polarized emission are effectively addressed.
The potential stickiness of pandemic-induced behavior changes in the United States
Authors: Salon Deborah , Conway Matthew Wigginton , Capasso da Silva Denise , Chauhan Rishabh Singh , Derrible Sybil , Mohammadian Abolfazl (Kouros) , Khoeini Sara , Parker Nathan , Mirtich Laura , Shamshiripour Ali , Rahimi Ehsan , Pendyala Ram M.
Published: June 2021

Human behavior is notoriously difficult to change, but a disruption of the magnitude of the COVID-19 pandemic has the potential to bring about long-term behavioral changes. During the pandemic, people have been forced to experience new ways of interacting, working, learning, shopping, traveling, and eating meals. A critical question going forward is how these experiences have actually changed preferences and habits in ways that might persist after the pandemic ends. Many observers have suggested theories about what the future will bring, but concrete evidence has been lacking. We present evidence on how much US adults expect their own postpandemic choices to differ from their prepandemic lifestyles in the areas of telecommuting, restaurant patronage, air travel, online shopping, transit use, car commuting, uptake of walking and biking, and home location. The analysis is based on a nationally representative survey dataset collected between July and October 2020. Key findings include that the “new normal” will feature a doubling of telecommuting, reduced air travel, and improved quality of life for some.
Effects of social capital, risk perception and awareness on environmental protection behavior
Authors: Su Fang , Song Nini , Shang Haiyang , Wang Jing , Xue Bing
Published: June 2021

Introduction:
Environmental protection is an essential issue for sustainable development, and its execution power mainly comes from individual environmental protection behavior. This study investigates the resident environmental protection behaviors and influencing factors in the ecologically fragile areas of western China based on a total of 1062 households by adopting the participatory assessment method. Then, this study used the structural equation model to empirically analyze the impact of social capital, environmental risk perception, and environmental awareness on residents’ environmental protection behavior.
Outcomes:
The results showed that environmental awareness is the basis for practicing environmental protection behavior, consistent with the existing research; social capital has a significant impact on residents’ environmental protection behavior, with an impact coefficient of 0.347. Hence, environmental risk perception has an indirect influence on environmental protection behavior through environmental awareness. Besides, compared with urban residents, rural residents’ environmental awareness and social capital have a stronger role in environmental protection behavior.
Conclusions:
The study clarified the influence path of residents’ environmental protection behavior, thus effectively providing a decision-making basis for the government to guide residents in the environmental governance system.
WDR62 regulates spindle dynamics as an adaptor protein between TPX2/Aurora A and katanin
Authors: Huang Junjie , Liang Zhuobi , Guan Cuirong , Hua Shasha , Jiang Kai
Published: June 2021

WDR62 is a microcephaly-related, microtubule (MT)-associated protein (MAP) that localizes to the spindle pole and regulates spindle organization, but the underlying mechanisms remain elusive. Here, we show that WDR62 regulates spindle dynamics by recruiting katanin to the spindle pole and further reveal a TPX2–Aurora A–WDR62–katanin axis in cells. By combining cellular and in vitro experiments, we demonstrate that WDR62 shows preference for curved segments of dynamic GDP-MTs, as well as GMPCPP- and paclitaxel-stabilized MTs, suggesting that it recognizes extended MT lattice. Consistent with this property, WDR62 alone is inefficient in recruiting katanin to GDP-MTs, while WDR62 complexed with TPX2/Aurora A can potently promote katanin-mediated severing of GDP-MTs in vitro. In addition, the MT-binding affinity of WDR62 is autoinhibited through JNK phosphorylation-induced intramolecular interaction. We propose that WDR62 is an atypical MAP and functions as an adaptor protein between its recruiting factor TPX2/Aurora A and the effector katanin to orchestrate the regulation of spindle dynamics.
Quantum geometric maps and their properties
Authors: Finocchiaro Marco , Jeong Yoobin , Oriti Daniele
Published: June 2021

Quantum geometric maps, which relate SU(2) spin networks and Lorentz covariant projected spin networks, are an important ingredient of spin foam models (and tensorial group field theories) for four-dimensional quantum gravity. We give a general definition of such maps, that encompasses all current spin foam models, and we investigate their properties at such general level. We then specialize the definition to see how the precise implementation of simplicity constraints affects features of the quantum geometric maps in specific models.
On wireless power transfer between coils in the presence of radiation
Authors: Shamonina Ekaterina , Solymar Laszlo , Kalinin Victor
Published: June 2021

Wireless power transfer (WPT) between magnetically coupled coils is necessarily accompanied by radiation that may hamper efficient power transfer and may cause harmful electromagnetic pollution. Hence careful control of the ratio between WPT and radiation is required. We have a formulation that allows the simultaneous determination of both the transferred and the radiated power by relying on both field and circuit theory and introducing the concept of a complex mutual inductance. Emphasis is placed on the visualisation of a radiative WPT system by using the streamlines of the Poynting vector. We perform several optimisations. We can find the parameters, coil radius, coil separation and load resistance, that maximise the ratio of load power to radiated power and at the same time minimise the radiated power. We identify the location of the singularities of the Poynting vector streamlines, the so-called P-points, and of the boundaries of a ‘power bubble’ surrounding the wireless two-coil system and forming an impenetrable barrier between the wireless power flow to the load and the power radiated out. A relationship between the size of the power bubble and the ratio between the useful load power and the harmful radiated power is established in a series of parametric studies. Field theory of Poynting vector streamlines is shown to quantitatively agree with the predictions of the circuit model. The new physical picture emerging for the power moving in space is expected to aid the design of complex practical WPT systems when radiation needs to be closely watched and for which a simple circuit model would fail to describe power distribution around the structure.
One-step fabrication of fiber optic SERS sensors via spark ablation
Authors: Kohut Attila , Horváth Viktória , Pápa Zsuzsanna , Vajda Balázs , Kopniczky Judit , Galbács Gábor , Geretovszky Zsolt
Published: June 2021

Spark ablation, a versatile, gas-phase physical nanoparticle synthesis method was employed to fabricate fiber-optic surface enhanced Raman scattering (SERS) sensors in a simple single-step process. We demonstrate that spark-generated silver nanoparticles can be simply deposited onto a fiber tip by means of a modified low-pressure inertial impactor, thus providing significant surface enhancement for fiber-based Raman measurements. The surface morphology of the produced sensors was characterized along with the estimation of the enhancement factor and the inter- and intra-experimental variation of the measured Raman spectrum as well as the investigation of the concentration dependence of the SERS signal. The electric field enhancement over the deposited silver nanostructure was simulated in order to facilitate the better understanding of the performance of the fabricated SERS sensors. A potential application in the continuous monitoring of a target molecule was demonstrated on a simple model system.
Practitioners’ views on new teaching material for introducing quantum optics in secondary schools
Authors: Bitzenbauer Philipp
Published: June 2021

In an earlier contribution in Physics Education (Bitzenbauer and Meyn 2020 Phys. Educ.

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055031), we presented a new teaching sequence on quantum optics on the secondary school level, and we reported on promising results of a first pilot study concerning its learning effectiveness. In the sense of design-based research, the developed teaching material is now being revised in several iteration steps and optimised through feedback from teachers from the field in order to favour the implementation of the new teaching approach to quantum physics in secondary schools. We present the design principles from the literature that our teaching material’s development is based on and report on a survey of physics teachers’ practical experiences with our teaching material.