bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of counterion size on polyelectrolyte conformations and thermodynamics
Authors: Ghosh Souradeep , Kundagrami Arindam
Published: February 2024

We present a theoretical model to study the effect of counterion size on the effective charge, size, and thermodynamic behavior of a single, isolated, and flexible polyelectrolyte (PE) chain. We analyze how altering counterion size modifies the energy and entropy contributions to the system, including the ion-pair free energy, excluded volume interactions, entropy of free and condensed ions, and dipolar attraction among monomer–counterion pairs, which result in competing effects challenging intuitive predictions. The PE self-energy is calculated using the Edwards–Muthukumar Hamiltonian, considering a Gaussian monomer distribution for the PE. The condensed ions are assumed to be confined within a cylindrical volume around the PE backbone. The dipolar and excluded volume interactions are described by the second and third virial coefficients. The assumption of freely rotating dipoles results in a first-order coil–globule transition of the PE chain. A more realistic, weaker dipolar attraction, parameterized in our theory, shifts it to a second-order continuous transition. We calculate the size scaling-exponent of the PE and find exponents according to the relative dominance of the electrostatic, excluded volume, or dipolar effects. We further identify the entropy- and energy-driven regimes of the effective charge and conformation of the PE, highlighting the interplay of free ion entropy and ion-pair energy with varying electrostatic strengths. The crossover strength, dependent on the counterion size, indicates that diminishing sizes favor counterion condensation at the expense of free ion entropy. The predictions of the model are consistent with trends in simulations and generalize the findings of the point-like counterion theories.
Harnessing the power of Microscale AcoustoFluidics: A perspective based on BAW cancer diagnostics
Authors: Harshbarger C. L.
Published: February 2024

Cancer directly affects one in every three people, and mortality rates strongly correlate with the stage at which diagnosis occurs. Each of the multitude of methods used in cancer diagnostics has its own set of advantages and disadvantages. Two common drawbacks are a limited information value of image based diagnostic methods and high invasiveness when opting for methods that provide greater insight. Microfluidics offers a promising avenue for isolating circulating tumor cells from blood samples, offering high informational value at predetermined time intervals while being minimally invasive. Microscale AcoustoFluidics, an active method capable of manipulating objects within a fluid, has shown its potential use for the isolation and measurement of circulating tumor cells, but its full potential has yet to be harnessed. Extensive research has focused on isolating single cells, although the significance of clusters should not be overlooked and requires attention within the field. Moreover, there is room for improvement by designing smaller and automated devices to enhance user-friendliness and efficiency as illustrated by the use of bulk acoustic wave devices in cancer diagnostics. This next generation of setups and devices could minimize streaming forces and thereby enable the manipulation of smaller objects, thus aiding in the implementation of personalized oncology for the next generation of cancer treatments.
Exploring anisotropic phases and spin transport in perovskite heterostructures: Insights into 3d/5d interfaces for antiferromagnetic spintronics
Authors: Sardar Suman , Vagadia Megha , Tank Tejas M. , Sahoo Jayaprakash , Rana D. S.
Published: February 2024

Transition metal oxides (TMOs) demonstrate a broad spectrum of properties encompassing electronic correlations, anisotropic transport, magnetism, and optical behavior. The anisotropy arises from both intrinsic crystal symmetry and extrinsic factors like epitaxial strain and structural asymmetry at TMO interfaces. Weiss and Neel's work has elucidated anisotropic magnetic behavior in antiferromagnetic (AFM) materials. AFM TMOs exhibit unique magnetotransport behavior, including weak antilocalization (WAL) and anisotropic magnetoresistance (AMR). Understanding the magnetic structure and band topology in AFM perovskites and their interfaces enables the tailored design of materials for spintronics and energy conversion. In few interfaces lacking inversion symmetry, Rashba spin–orbit coupling (SOC) induces WAL, a quantum correction in conductivity in a two-dimensional electronic system. Electron accumulation and charge transfer across 3d, 5d transition metal-based perovskite interfaces affect WAL and AMR, as observed in 3d/3d and 3d/5d AFM heterostructures, respectively. Advancements in spintronics rely on exploring spin-dependent transport anisotropy. This review focuses on various scattering mechanisms, categorized as extrinsic and intrinsic, in anisotropic transport, particularly in 3d/5d AFM superlattices. The WAL scattering mechanism depends on both intrinsic factors related to Rashba SOC-induced band topology and extrinsic sources like spin impurities and lattice ions. Moreover, the investigation into AMR mechanisms involves the application of impurity-based extrinsic scattering models, which are aligned with the Rashba and Dresselhauss models on Fermi surfaces. This exploration specifically targets the interface of two-band insulators, exemplified by LaAlO3/SrTiO3 and LaVO3/KTaO3. Furthermore, this model achieves comprehensive coverage, extending its applicability to 3d/5d AFM heterostructures like LaMnO3/SrIrO3 and CaMnO3/CaIrO3. Additionally, the intrinsic scattering mechanism tied to Berry phase effects related to band topology is studied, focusing on the CaMnO3/CaIrO3 superlattice. Despite manipulation challenges stemming from reduced stray fields, AFM materials show potential in interface physics and applications within the realm of spintronics.
Exchange-only virial relation from the adiabatic connection
Authors: Laestadius Andre , Csirik Mihály A. , Penz Markus , Tancogne-Dejean Nicolas , Ruggenthaler Michael , Rubio Angel , Helgaker Trygve
Published: February 2024

The exchange-only virial relation due to Levy and Perdew is revisited. Invoking the adiabatic connection, we introduce the exchange energy in terms of the right-derivative of the universal density functional w.r.t. the coupling strength λ at λ = 0. This agrees with the Levy–Perdew definition of the exchange energy as a high-density limit of the full exchange–correlation energy. By relying on v-representability for a fixed density at varying coupling strength, we prove an exchange-only virial relation without an explicit local-exchange potential. Instead, the relation is in terms of a limit (λ ↘ 0) involving the exchange–correlation potential vxcλ, which exists by assumption of v-representability. On the other hand, a local-exchange potential vx is not warranted to exist as such a limit.
Design and investigation of a capacitance-coupling pre-ionized sharpening switch
Authors: Zhai Rongxiao , Yin Jiahui , Hu Yixiang , Qiu Mengtong , Zhang Tianyang , Wu Qilin , Cong Peitian
Published: February 2024

The sharpening switch is one of the most important elements in the trigger generator, which is used to sharpen the front of the trigger pulse. The breakdown performance of the sharpening switch has an important influence on the output and stability of the trigger generator. In this paper, a novel 200 kV capacitance-coupling pre-ionized sharpening switch, which can realize pre-ionization by dividing voltage through its own structural capacitances, is proposed and investigated. In order to obtain the optimal parameters of the pre-ionized sharpening switch, the influences of the electrode structure, electrode material, main gap distance, and pre-ionized gap distance on the breakdown performance are studied experimentally. The experimental results show that the electrode structure with a circular knife-edged cathode and a plate-shaped anode has the smallest breakdown jitter, followed by the needle-plate structure and the tapered ball-head structure. The stainless steel electrode has the smallest jitter, followed by graphite, aluminum, and brass electrodes. When the gap distances of the main gap and the pre-ionized gap are 13 and 1.5 mm, respectively, the breakdown stability of the pre-ionized sharpening switch is the best. Under an input voltage pulse with a rise time of about one microsecond, the jitter of the capacitance-coupling pre-ionized sharpening switch with the optimal parameters is 6.08 ns, which is about 0.6% of the rise time of the input pulse. The jitter decreases by 44.5% compared to the switch without pre-ionization. The rise time of the output pulse is sharpened to 17 ns, corresponding to a voltage rise rate of more than 11 kV/ns.
Point projection radiography of electromagnetically accelerated flyer plates with an external X-pinch driver
Authors: Read J. , Burdiak G. , Bland S. N. , Caballero Bendixsen L. S. , Paxton-Fear L. , Niasse N. , Dobranszki C. , Hawker N.
Published: February 2024

A platform for flyer plate benchmarking experiments has been developed, with an external X-pinch driver for point projection radiography. The experiments were performed using CEPAGE, a low inductance pulsed power machine at First Light Fusion (2 MA, 1.4 µs), with a new vacuum transmission line and flyer load hardware designed specifically to give a line of sight for radiography. A broadband 10–20 keV x-ray source was produced by a portable X-pinch driver (140 kA, 350 ns) [Strucka et al., Matter Radiat. Extremes 7, 016901 (2021)] and was used to image the flyer. Radiography compliments the pre-existing diagnostic suite, which consists of current probes, velocimetry, and side-on optical probing of the impact shock transmitted into a transparent sample. The platform allows for significant insights into the 2D and 3D nature of the flyer launch, such as deformation and instability formation. It was used to diagnose a 10 × 9 × 1 mm3 aluminum flyer, which reached a peak velocity of 4.2 km s−1 before impact with a poly(methylmethacrylate) sample. The experimental configuration, on-shot source characterization, and the results from two flyer plate experiments on CEPAGE are discussed.
Pulsed ion deflection to overcome detector saturation in cryogenic ice sampling
Authors: Samarth P. , Bulak M. , Paardekooper D. , Chuang K.-J. , Linnartz H.
Published: February 2024

In 2014, we introduced a new experimental approach to study the UV photo-processing of cryogenic ices of astrophysical interest using laser ablation in a combination of ionization and time-of-flight mass spectrometry (ToF-MS). The setup, Mass Analytical Tool to Research Interstellar ICES, allowed us to detect newly formed species at low abundances. However, we found that with the increase in molecular complexity over the years, the detection of larger photoproducts was hindered by the dynamic range of detectors used. Here, we introduce a method to overcome this issue that we expect to be useful for similar applications in other research fields. The concept is based on a precisely controlled high-energy pulser that regulates the voltage across the deflection plates of the ToF-MS instrument to deflect the most abundant species and prevent them from reaching the detector. In this way, the detector sensitivity can be increased from an operating voltage of 2500 V up to 3000 V. The applicability is first illustrated in the simple case of an argon matrix, where 40Ar+ ions are deflected to increase the detection sensitivity for 40Ar2+ at m/z = 20 and 40Ar2+ at m/z = 80 by a factor 30. Similarly, it is shown that substantially larger complex organic molecules, an important species in astrochemical reaction networks, can be measured for UV irradiated methanol ice.
Pressure-induced metallization and enhanced photoelectric activity in layered tin disulfide
Authors: Shi Yuyang , Wu Min , Yue Lei , Wang Kai , Li Quanjun , Wu Ye , Ye Gonglan , Huang Haijun
Published: February 2024

Two-dimensional layered metal dichalcogenides have given rise to considerable interest in electronics and optoelectronics fields because of their excellent physical and chemical properties and promising applications. Tin disulfide (SnS2) is an important member of them due to its environment-friendly and resource-rich characteristics. Here, a series of in situ electrical transport experiments and photocurrent measurements under high pressure have been performed to investigate the electrical and opto-electrical properties of 4H-SnS2. With increasing pressure, the electrical resistivity of 4H-SnS2 decrease significantly, leading to a transition from semiconducting to metallic state above 58.6 GPa. The increase in pressure results in a substantial enhancement in photoelectric activity, indicating the extensive potential of utilizing pressure as a trigger for in situ optoelectronic applications. Combined with our previous results of x-ray diffraction and optical absorption at high pressure, pressure-induced structural distortion, bandgap narrowing, metallization, and enhancement of photoelectric activity of 4H-SnS2 are tunable and reversible, which are of great significance for both fundamental research and device design.
An “Observable” horseshoe map
Authors: Zhang Xu , Wang Yukai , Chen Guanrong
Published: February 2024

In this article, a family of diffeomorphisms with growing horseshoes contained in global attracting regions is presented, where the dimension of the unstable direction can be any fixed integer and a growing horseshoe means that the number of the folds of the horseshoe is increasing as a parameter is varied. Moreover, it is demonstrated that the horseshoe-like attractors are observable for certain parameters.
Minimum resistance radius for gas–liquid spontaneous imbibition in microtubes
Authors: Ding Heying , Song Fuquan , Huang Xiaohe , Wang Yongzheng , Zhang Yapu , Yang Zhengming
Published: February 2024

Spontaneous imbibition is the natural movement of a wetting phase liquid within porous media or microtubes. Such flow occurs commonly in nature and industrial settings, where gas and liquid phases flow spontaneously through porous materials. To delve deeper into the characteristics and mechanisms of gas–liquid two-phase spontaneous imbibition at the microscale, this paper establishes a mathematical model considering acceleration. Through both numerical simulations and experiments, the detailed analysis of de-ionized water's spontaneous imbibition within microtubes sheds light on interface phenomena at the microscale. The results highlight the pronounced influence of the microtube radius and gas-water interfacial tension on the imbibition process. By combining experimental work, theoretical analysis, and numerical simulations, this study identifies the minimum resistance radius—a tube radius leading to the shortest imbibition time to the top. The research underscores the significance of considering acceleration and provides a theoretical groundwork for leveraging spontaneous imbibition. It also holds potential value for applications in microfluidic technology, nanomaterial synthesis, and biomedical fields.
Photo-driven water oxidation performed by supramolecular photocatalysts made of Ru(II) photosensitizers and catalysts
Authors: Cancelliere Ambra M. , Arrigo Antonino , Galletta Maurilio , Nastasi Francesco , Campagna Sebastiano , La Ganga Giuseppina
Published: February 2024

Two new supramolecular photocatalysts made of covalently linked Ru(II) polypyridine chromophore subunits ([Ru(bpy)3]2+-type species; bpy = 2,2′-bipyridine) and [RuL(pic)2] (L = 2,2′-bipyridine-6,6′-dicarboxylic acid; pic = 4-picoline) water oxidation catalyst subunits have been prepared. The new species, 1 and 2, contain chromophore and catalyst subunits in the molecular ratios 1:1 and 1:2, respectively. The model chromophore species [Ru(bpy)2(L1)]2+ (RuP1; L1=4-[2-(4-pyridyl)-2-hydroxyethyl]-4-methyl-2,2′-bipyridine) and [Ru(bpy)2(L2)]2+ (RuP2; L2 = 4,4′-bis[2-(4-pyridyl)-2-hydroxyethyl]-2,2′-bipyridine) have also been prepared. The absorption spectra, oxidation behavior, and luminescent properties of 1 and 2 have been studied, and the results indicate that each subunit largely maintains its own properties in the supramolecular species. However, the luminescence of the chromophore subunits is significantly quenched in 1 and 2 in comparison with the luminescence of the respective model species. Both 1 and 2 exhibit catalytic water oxidation in the presence of cerium ammonium nitrate, exhibiting an I2M mechanism, with a better efficiency than the known catalyst [RuL(pic)2] under the same experimental conditions. Upon light irradiation, in the presence of persulfate as a sacrificial acceptor agent, 1 and 2 are more efficient photocatalysts than a system made of separated [Ru(bpy)3]2+ and [RuL(pic)2] species, highlighting the advantage of using multicomponent, supramolecular species with respect to isolated species. The O–O bond formation step is I2M, even in the photo-driven process. The photocatalytic process of 2 is more efficient than that of 1, with the turnover frequency reaching a value of 1.2 s−1. A possible reason could be an increased local concentration of catalytic subunits in the needed bimolecular assembly required for the I2M mechanism in 2 with respect to 1, a consequence of the presence of two catalytic subunits in each multicomponent species 2.
Nonlinear magnonic coupler using backpropagating surface spin waves
Authors: Martyshkin A. A. , Sheshukova S. E. , Sadovnikov A. V.
Published: February 2024

We investigated a spin-wave propagation in a magnon-crystal structure formed from two lateral microwaveguides separated by a one-dimensional antidot array. The mechanisms of control of the backpropagating regime of the surface spin waves both with geometry tuning and with power level variation in the case of in-plane magnetization are investigated by the method of micro-magnetic modeling and the experimental method of Brillouin light scattering spectroscopy. It was shown that for the case of spin-waves propagation through the isolated channels the shape anisotropy in the coupling region can be tuned effectively by a variation of the distance between the channels. The regime of nonlinear switching of the signal and backward propagation was observed in microwave and Brillouin spectroscopy measurements. The proposed effect of the signal separation manifests itself in the spatially and frequency-selective regimes of spin-wave propagation. Proposed spin-wave coupler opens an alternative way for the design of the functional interconnections of spin-wave based units in the planar magnonic networks.
Transformation of topological states in three-dimensional photonic crystal under magnetic field modulation
Authors: Li Xiaoxue , Rui Guanghao , He Jun , Gu Bing
Published: February 2024

The realization and modulation of high-order topological states in three-dimensional (3D) photonic crystals (PCs) hold great significance for practical applications in optical communication, optical information processing, and optical computing. However, they have encountered technological challenges due to the difficulty in achieving a complete bandgap in 3D PCs. To address this issue, we introduce a design for a 3D PC based on the Su–Schrieffer–Heeger (SSH) model that exhibits distinctive topological surface states, topological hinge states, and topological corner states. Furthermore, these three types of topological states can be interconverted through the modulation of magnetic field because the topological states are closed and extremely sensitive to the structure, which are modulated by the magnetic field. This intriguing capability holds potential applications in the manipulation of optical flow, optical signal storage, and magnetic field sensors.
Bias-tunable temperature coefficient of resistance in Ge transistors
Authors: Behrle R. , Smoliner J. , Wind L. , Nazzari D. , Lugstein A. , Weber W. M. , Sistani M.
Published: February 2024

Ge-based bolometers are widely used for near-infrared detection for a broad range of applications such as thermography or chemical analysis. Notably, for the thermometers used in bolometers, integration, scaling, and sensitivity as well as functionality are of utmost importance. In this regard, Ge exhibits a favorable temperature sensitivity due to the relatively low bandgap and a high intrinsic charge carrier concentration. In this work, we demonstrate a nanoscale thermometer for bolometric applications on the base of Ge-on-insulator nanosheets with monolithic Al source/drain contacts envisioned for future wafer-scale integration. Importantly, electrostatic gating of the nanosheets allows the operation as a Schottky barrier field-effect transistor, providing tunability of the energy landscape and the involved charge carrier injection in interaction with the metal-semiconductor junctions. In this approach, the top-gate electrode and drain contact are connected, thus resembling a two-terminal device with bias-tunable temperature coefficient of resistance (TCR) values between 0%/K and −3.8%/K in the temperature range of T = 125–150 K. Moreover, in this configuration, even at room temperature, a maximum TCR value of −1.6%/K is achieved. The bias-tunable TCR exhibited in these devices may enable advanced concepts for room temperature bolometric applications and allow co-integration with nanoelectronics.
Improving the hydraulic performance of a high-speed submersible axial flow pump based on CFD technology
Authors: Rong Lu , Böhle Martin , Yandong Gu
Published: February 2024

The hydraulic performance of a high-speed submersible axial flow pump is investigated to reduce its energy consumption. A more efficient and stable optimization method that combines parametric design, computational fluid dynamics, and a computer algorithm is proposed. The main aim is to broaden the high-efficiency operating zone, so the average efficiency under multiple conditions is optimized while considering rotor–stator matching. The design-of-experiments method and a radial-basis-function neural network are combined to form the optimization platform, and automatic optimization of the pump design is realized through repeated execution of design and simulation. The flow loss mechanism inside the pump is studied in depth via the entropy generation rate, and regression analysis shows that the pump efficiency is influenced mainly by the blade angles. After optimization, the target efficiency is increased by 8.34%, and the flow field distribution shows that the channel vortex and hydraulic loss are controlled effectively. Finally, the results are validated by experiment. The proposed optimization approach has advantages in saving manpower and obtaining globally optimal solutions.
Hydration numbers of biologically relevant divalent metal cations from ab initio molecular dynamics and continuum solvation methods
Authors: Kalvoda Tadeáš , Martinek Tomas , Jungwirth Pavel , Rulíšek Lubomír
Published: February 2024

Hydration and, in particular, the coordination number of a metal ion is of paramount importance as it defines many of its (bio)physicochemical properties. It is not only essential for understanding its behavior in aqueous solutions but also determines the metal ion reference state and its binding energy to (bio)molecules. In this paper, for divalent metal cations Ca2+, Cd2+, Cu2+, Fe2+, Hg2+, Mg2+, Ni2+, Pb2+, and Zn2+, we compare two approaches for predicting hydration numbers: (1) a mixed explicit/continuum DFT-D3//COSMO-RS solvation model and (2) density functional theory based ab initio molecular dynamics. The former approach is employed to calculate the Gibbs free energy change for the sequential hydration reactions, starting from [M(H2O)2]2+ aqua complexes to [M(H2O)9]2+, allowing explicit water molecules to bind in the first or second coordination sphere and determining the most stable [M(H2O)n]2+ structure. In the latter approach, the hydration number is obtained by integrating the ion–water radial distribution function. With a couple of exceptions, the metal ion hydration numbers predicted by the two approaches are in mutual agreement, as well as in agreement with the experimental data.
Water transportation using a low-height overhang structure along with an expansion pressure of bubbles in a nucleate boiling region
Authors: Sugioka Hideyuki , Miyauchi Atsushi , Oshiro Atsushi
Published: February 2024

Effective use of low-grade energy is a vital issue for a more sustainable society. Here, we propose a water pump using a low-height overhang structure that effectively uses an expansion pressure of bubbles in a nucleate boiling region. Specifically, by fabricating a periodic overhang structure on a brass surface, we show that a ∼20 mm/s net flow can be generated in a nucleate boiling regime. In addition, by observing bubbles with a high-speed camera of 960 fps, we find that bubbles are generated selectively in the overhang structure and grow to push out water in a lateral direction. Furthermore, by proposing a simple model that considers the expansion pressure of bubbles, we succeed in explaining the experimental results to some extent. Our findings should contribute to the effective use of low-grade energy in a nucleate boiling regime.
Finite temperature dynamics of the Holstein–Tavis–Cummings model
Authors: Hou Erqin , Sun Kewei , Gelin Maxim F. , Zhao Yang
Published: February 2024

By employing the numerically accurate multiple Davydov Ansatz (mDA) formalism in combination with the thermo-field dynamics (TFD) representation of quantum mechanics, we systematically explore the influence of three parameters—temperature, photonic-mode detuning, and qubit–phonon coupling—on population dynamics and absorption spectra of the Holstein–Tavis–Cummings (HTC) model. It is found that elevated qubit–phonon couplings and/or temperatures have a similar impact on all dynamic observables: they suppress the amplitudes of Rabi oscillations in photonic populations as well as broaden the peaks and decrease their intensities in the absorption spectra. Our results unequivocally demonstrate that the HTC dynamics is very sensitive to the concerted variation of the three aforementioned parameters, and this finding can be used for fine-tuning polaritonic transport. The developed mDA-TFD methodology can be efficiently applied for modeling, predicting, optimizing, and comprehensively understanding dynamic and spectroscopic responses of actual molecular systems in microcavities.
Temperature-dependent dielectric relaxation measurements of (acetamide + K/Na SCN) deep eutectic solvents: Decoding the impact of cation identity via computer simulations
Authors: Mondal Jayanta , Maji Dhrubajyoti , Biswas Ranjit
Published: February 2024

The impact of successive replacement of K+ by Na+ on the megahertz–gigahertz polarization response of 0.25[fKSCN + (1 − f)NaSCN] + 0.75CH3CONH2 deep eutectic solvents (DESs) was explored via temperature-dependent (303 ≤ T/K ≤ 343) dielectric relaxation (DR) measurements and computer simulations. Both the DR measurements (0.2 ≤ ν/GHz ≤ 50) and the simulations revealed multi-Debye relaxations accompanied by a decrease in the solution static dielectric constant (ɛs) upon the replacement of K+ by Na+. Accurate measurements of the DR response of DESs below 100 MHz were limited by the well-known one-over-frequency divergence for conducting solutions. This problem was tackled in simulations by removing the zero frequency contributions arising from the ion current to the total simulated DR response. The temperature-dependent measurements revealed a much stronger viscosity decoupling of DR times for Na+-containing DES than for the corresponding K+ system. The differential scanning calorimetry measurements indicated a higher glass transition temperature for Na+-DES (∼220 K) than K+-DES (∼200 K), implying more fragility and cooperativity for the former (Na+-DES) than the latter. The computer simulations revealed a gradual decrease in the average number of H bonds (⟨nHB⟩) per acetamide molecule and increased frustrations in the average orientational order upon the replacement of K+ by Na+. Both the measured and simulated ɛs values were found to decrease linearly with ⟨nHB⟩. Decompositions of the simulated DR spectra revealed that the cation-dependent cross interaction (dipole-ion) term contributes negligibly to ɛs and appears in the terahertz regime. Finally, the simulated collective single-particle reorientational relaxations and the structural H-bond fluctuation dynamics revealed the microscopic origin of the cation identity dependence shown by the measured DR relaxation times.
Flutter limitation of drag reduction by elastic reconfiguration
Authors: Boukor Maryam , Choimet Augustin , Laurendeau Éric , Gosselin Frédérick P.
Published: February 2024

Through experiments, we idealize a plant leaf as a flexible, thin, rectangular plate clamped at the midpoint and positioned perpendicular to an airflow. Flexibility of the structure is considered as an advantage at moderate flow speed because it allows drag reduction by elastic reconfiguration, but it can also be at the origin of several flow-induced vibration phenomena at higher flow speeds. A wind tunnel campaign is conducted to identify the limitation to elastic reconfiguration that dynamic instability imposes. Here, we show by increasing the flow speed that the flexibility permits a considerable drag reduction by reconfiguration, compared to the rigid case. However, beyond the stability limit, vibrations occur and limit the reconfiguration. This limit is represented by two dimensionless numbers: the mass number and the Cauchy number. Our results reveal the existence of a critical Cauchy number below which static reconfiguration with drag reduction is possible and above which a dynamic instability with important fluctuating loads is present. The critical dimensionless velocity is dependent on the mass number. Flexibility is related to the critical reduced velocity and allows defining an optimal flexibility for the structure that leads to a drag reduction by reconfiguration while avoiding dynamic instability. Furthermore, experiments show that our flexible structure can exhibit two vibration modes: symmetric and anti-symmetric, depending on its mass number. Because the system we consider is bluff yet aligned with the flow, it is unclear whether the vibrations are due to a flutter instability or vortex-induced vibration or a combination of both phenomena.
Magnons in a two-dimensional Weyl magnet
Authors: Chen Ying-Jiun , Chuang Tzu-Hung , Hanke Jan-Philipp , Mokrousov Yuriy , Blügel Stefan , Schneider Claus M. , Tusche Christian
Published: February 2024

The discovery of topological states of matter has led to a revolution in condensed-matter science. While a non-trivial band topology in a material is often associated with intriguing transport properties, much less attention has been given to the impact on spin dynamics and non-equilibrium magnetization states. Here, we provide evidence that a chiral asymmetric magnon dispersion in the two-dimensional Weyl magnet Fe/W(110) is related to the presence of Weyl fermions close to the Fermi energy and surface Fermi arcs. We find that the large anomalous Hall conductivity and the Dzyaloshinskii–Moriya interaction are attributed to the non-trivial band topology in the composite momentum-magnetization space. Our results show the direct impact of Weyl fermions on both the charge and spin dynamics in a two-dimensional magnet. Unveiling these principles can promote innovative technologies in magnonics by utilizing topological materials, where magnons and non-trivial topological electronic states can be manipulated through magnetization.
Tunable anomalous Hall effect and Curie temperature in perpendicular magnetic anisotropic lanthanum doped NiCo2O4 film
Authors: Zhang Yi , Chen Xuegang , Ji Xianghao , Wang Heng , Zheng Biao , Xue Mingzhu , Yang Jinbo , Tian Mingliang
Published: February 2024

Perpendicular magnetic anisotropic NiCo2O4 (NCO) films show volatile physical properties due to the complicated ion occupation/valence disproportion, making it feasible to be manipulated. In this work, the tunable anomalous Hall effect is observed in high-quality lanthanum (La) doped NCO films grown by the off-axis RF sputtering technique. It reveals that the longitudinal resistance (Rxx) significantly increases as the growth of La doping level, while the Curie temperature (TC) decreases with the rising of La doping level. A universal scaling law between the longitudinal conductance (σxx) and the anomalous Hall conductance (σxy), including the terms of dirty scaling mechanism, intrinsic contribution, and side jump, is proposed to explain the observed anomalous Hall effect. Additionally, an intrinsic linear relation between σxx and TC is revealed. The evolution of anomalous Hall resistance (RA), TC, and Rxx is closely related to the complex valence state/occupation of Ni ions induced by La doping. This work provides a strategy to manipulate the physical properties of NCO film, making it a potential material for spintronic applications.
Electric field control of magnetic anisotropy and model for oriented Co/graphene design
Authors: Chang Cheng-Hsun-Tony , Chow Yu-Ting , Jiang Pei-Cheng , Yang Ting-Xun , Tsay Jyh-Shen
Published: February 2024

Electric field controlled magnetic devices have attracted interest in the area of magnetic recording research, owing to their lower power consumption and high stability. While heterostructures composed of Co and carbon materials exhibit unique properties, our understanding of the magnetic properties of Co on graphene with a wavelike structure and related electric field-controlled phenomena remains limited. Here, we demonstrate the preparation of a customized Co/graphene structure, in which the controllability of the coercive force is enhanced. Taking the coercive force and geometric factor of Co into consideration, a shape-dependent magnetic anisotropy is proposed, which sufficiently explains the correlation between the coercive force and the aspect ratios of the Co stripes. For the magnetic field perpendicular to the bottom lines of canyons, the adjustment capability of the coercive force is enhanced under conditions of a more negatively charged surface. Based on the large electric field and related magnetic anisotropy energy, a ferro-ionic control (FeIC) model is proposed, which describes the relationship between the electric potential and coercive force in electrified conditions. Based on a FeIC model with a preferred orientation, we propose a design of an integrated FeIC inductor with field tunability that could strongly impact the field of integrated-circuit design, resulting in wider applications and functionalities of chips.
The identification of gas–liquid two-phase flow patterns in a centrifugal pump with an imbalanced sample and variable rotational speeds
Authors: Li Su-Ting , Li Rui-Lin , He Deng-Hui , Huang Rui , Sun Shuai-Hui
Published: February 2024

Due to the effects of the working medium and external conditions, centrifugal pumps often produce complex gas–liquid two-phase flows during operation. The entrainment of gas can lead to a significant decrease in the pressure head of the centrifugal pump and a serious reduction in conveyance efficiency. Therefore, in the absence of visualization or noninvasive techniques, the question of how to predict and model the flow status inside the pump is a key issue that needs to be urgently addressed. Using experimental data for gas–liquid two-phase flows in centrifugal pumps, this paper proposes a flow pattern identification model based on one-dimensional pressure increment signals. This deep learning model consists of convolutional neural networks and bidirectional gated recurrent units. Bayesian optimization is used for automatic hyperparameter tuning, and under the premise of balanced data distribution, the model achieves an identification rate of 0.98 on the test set. Subsequently, addressing the issue of the uneven sample distribution in centrifugal pumps due to their poor gas-carrying capacity, a data augmentation model based on the conditional Wasserstein generative adversarial network with gradient penalty approach is proposed based on the predictive model. Finally, to establish a flow pattern identification method with good extrapolation capability, a transfer learning strategy that accounts for the domain adaptation problem is introduced to the dataset with variable speeds based on the previous two studies. This method achieves knowledge transfer from the source domain to the target domain with a recognition rate of over 0.988 without hyperparameter optimization.
Revealing the temperature-driven Lifshitz transition in p-type Mg3Sb2-based thermoelectric materials
Authors: Xie Sen , Liu Keke , Li Chunxia , Yan Fan , Ouyang Yujie , Ge Haoran , Li Xianda , Su Xianli , Liu Yong , Liu Wei , Tang Xinfeng
Published: February 2024

The manipulation of native atomic defects and their thermal excitations plays vital roles in the thermoelectric performance of Mg3Sb2-based materials. While native defects manipulation has been intensively studied in p-type Mg3Sb2, there exists interesting unsolved issue regarding the abnormal semiconducting electrical behavior in most of samples. In this work, high quality Mg3Sb2 and Mg3Bi2 (00l) films are fabricated by molecular beam epitaxy technique, while variable temperature angle-resolved photoemission spectroscopy and scanning tunneling spectroscopy measurements are utilized for resolving the aforementioned issue. The thermal excitation of Mg interstitials (the electron donor) results in an obvious downshift of valence bands with rising temperature in both the p-type Mg3Sb2 and Mg3Bi2. Meanwhile, the interesting temperature-driven Lifshitz transition is discovered in the p-type Mg3Sb2, as indicated by the change of Fermi surface topology. Above the Lifshitz transition temperature, the Fermi level of p-type Mg3Sb2 will enter the bandgap, which leads to the abnormal semiconducting electrical behavior. This work discloses the excitation of native defects and temperature-driven Lifshitz transition, which are the main causes for the anomalies in electrical transport of p-type Mg3Sb2-based materials, and also provides valuable insights for further improving their thermoelectric performance.
Large-scale evidence for logarithmic effects of word predictability on reading time
Authors: Shain Cory , Meister Clara , Pimentel Tiago , Cotterell Ryan , Levy Roger
Published: February 2024

During real-time language comprehension, our minds rapidly decode complex meanings from sequences of words. The difficulty of doing so is known to be related to words’ contextual predictability, but what cognitive processes do these predictability effects reflect? In one view, predictability effects reflect facilitation due to anticipatory processing of words that are predictable from context. This view predicts a linear effect of predictability on processing demand. In another view, predictability effects reflect the costs of probabilistic inference over sentence interpretations. This view predicts either a logarithmic or a superlogarithmic effect of predictability on processing demand, depending on whether it assumes pressures toward a uniform distribution of information over time. The empirical record is currently mixed. Here, we revisit this question at scale: We analyze six reading datasets, estimate next-word probabilities with diverse statistical language models, and model reading times using recent advances in nonlinear regression. Results support a logarithmic effect of word predictability on processing difficulty, which favors probabilistic inference as a key component of human language processing.
Structural basis for CFTR inhibition by CFTR
inh
-172
Authors: Young Paul G. , Levring Jesper , Fiedorczuk Karol , Blanchard Scott C. , Chen Jue
Published: February 2024

The cystic fibrosis transmembrane conductance regulator (CFTR) is an anion channel that regulates electrolyte and fluid balance in epithelial tissues. While activation of CFTR is vital to treating cystic fibrosis, selective inhibition of CFTR is a potential therapeutic strategy for secretory diarrhea and autosomal dominant polycystic kidney disease. Although several CFTR inhibitors have been developed by high-throughput screening, their modes of action remain elusive. In this study, we determined the structure of CFTR in complex with the inhibitor CFTR
inh
-172 to an overall resolution of 2.7 Å by cryogenic electron microscopy. We observe that CFTR
inh
-172 binds inside the pore near transmembrane helix 8, a critical structural element that links adenosine triphosphate hydrolysis with channel gating. Binding of CFTR
inh
-172 stabilizes a conformation in which the chloride selectivity filter is collapsed, and the pore is blocked from the extracellular side of the membrane. Single-molecule fluorescence resonance energy transfer experiments indicate that CFTR
inh
-172 inhibits channel gating without compromising nucleotide-binding domain dimerization. Together, these data reconcile previous biophysical observations and provide a molecular basis for the activity of this widely used CFTR inhibitor.
Stylistics, pop culture, and educational research
Authors: Mandala Susan
Published: February 2024

This paper explores how educational research and stylistics, fields that rarely intersect, can be in closer
dialogue in the study of pop culture texts, artefacts of interest to scholars in both disciplines. I establish in a systematized
critical interpretive synthesis that educational research tends to treat pop culture texts as documents. I show that this in turn
tends to drive content-focused analyses that stay, from a linguistic point of view, at the surface of the texts. In response, I
offer a stylistic analysis of a pop culture text, an episode from the situation comedy The Big Bang Theory that
features an English language learner. I employ conversation analysis to interpret the dialogue and demonstrate how a linguistic
approach opens up readings on the discursive construction of phenomena such as belonging and exclusion.
“Strangers in the night, exchanging glasses”
Authors: West David
Published: February 2024

This article deals with the phenomenon of mondegreens, a term coined in 1954 to describe when a
listener to a pop song mishears the lyrics and sings her own version instead, as in Strangers in the night, exchanging
glasses (rather than glances). A distinction is made in the literature between
within-language mondegreens, which occur when a listener produces a mondegreen in the same language as the
original (as in Strangers in the night, exchanging glasses), and cross-language mondegreens,
when a listener produces a mondegreen in a different language to the original (as in the German Agathe Bauer for
the English I’ve got the power). The key question that the article addresses is: Why do we mondegreen? After
providing an overview of the approaches to both within-language and cross-language mondegreens that have been taken in linguistics
and related disciplines, the article then draws on cognitive psychology and its approach to creativity to argue that mondegreens
are in fact better understood not so much as simple errors as products of the creative mind.
Literary translators in-between
Authors: Ruffo Paola
Published: February 2024

This article reports on a study of literary translators’ self-imaging strategies and their attitudes towards
technology in the context of the increasing technologisation of the profession. Literary translators’ self-image emerges as the
sum of personal as well as professional characteristics, which is in contrast with the way they believe outsiders perceive them.
Participants’ narratives highlight the feeling of being misunderstood by those outside the profession, and inhabiting an
in-between space, having to reconcile both contradictions inherent to literary translation and those engendered by differing views
of the profession and the role technology plays in it. Results open up a new path for the study of literary translators’
self-imaging strategies by centring their voices as a means to better understand if and how technology can (1) empower translators
of creative texts and (2) reduce the gap between their view of the profession and other stakeholders.
Moonwalking molecular machines: Unraveling the choreography of myosin filament assembly
Authors: Gurley Noah J. , Peifer Mark
Published: February 2024

We have made tremendous progress in identifying the machines that shape the architecture of actin filaments. However, we know less about the mechanisms mediating myosin assembly at the supramolecular level. In this issue, Quintanilla et al. (https://doi.org/10.1083/jcb.202305023) provide important new insights into this process.
Consistency of Lorentz-invariance violation neutrino scenarios in time delay analyses
Authors: Carmona J M , Cortés J L , Reyes M A
Published: February 2024

Modifications inspired by quantum gravity in the kinematics of special relativity can manifest in various ways, including anomalies in the time of flight of massless particles and the emergence of decay channels for otherwise stable particles. Typically, these effects are studied independently; however, it may be necessary to combine both to perform a consistent analysis. In this work, we study the interplay between time-of-flight anomalies and neutrino instability in the context of a flavour-independent high-energy Lorentz-invariance violation (LIV) in the neutrino sector. Ensuring compatibility between both types of effects imposes strong constraints on the existence of early neutrinos with energies exceeding a maximum value determined by the scale of new physics. Such constraints depend on the specific LIV scenario and should be integrated into searches for high-energy neutrinos from gamma-ray bursts exhibiting LIV time shifts.
The Synge G-Method: cosmology, wormholes, firewalls, geometry
Authors: Ellis G F R , Garfinkle D
Published: February 2024

Unphysical equations of state result from the unrestricted use of the Synge G-trick of running the Einstein field equations backwards; in particular often this results in

ρ
+
p
<
0

which implies negative inertial mass density, which does not occur in reality. This is the basis of some unphysical spacetime models including phantom energy in cosmology and traversable wormholes. The slogan ‘ER = EPR’ appears to have no basis in physics and is merely the result of vague and unbridled speculation. Wormholes (the ‘ER’ of the slogan) are a mathematical curiosity of general relativity that have little to no application to a description of our Universe. In contrast quantum correlations (the ‘EPR’ of the slogan) are a fundamental property of quantum mechanics that follows from the principle of superposition and is true regardless of the properties of gravity. The speculative line of thought that led to ‘ER = EPR’ is part of a current vogue for anti-geometrical thinking that runs counter to (and threatens to erase) the great geometrical insights of the global structure program of general relativity.