bluuebunny/crossref_metadata_2025 huggingface dataset:
Hole transport mechanism at high temperatures in p-GaN/AlGaN/GaN heterostructure
Authors: Sikder Bejoy , Hossain Toiyob , Xie Qingyun , Niroula John , Rajput Nitul S. , Teo Koon Hoo , Amano Hiroshi , Palacios Tomás , Chowdhury Nadim
Published: June 2024

This Letter reports an investigation of hole transport in p-GaN/AlGaN/GaN heterostructures through experimental and theoretical analyses under varied conditions. Highly non-linear current–voltage (I–V) characteristics, obtained via the linear transmission line method measurements, are utilized for this study. At low bias voltage, the transport can be ascribed to the Schottky nature of the contact, while at high bias, the conduction is observed to be governed by space-charge limited current (SCLC). The Schottky characteristics (Schottky barrier height and non-ideality factor) and the SCLC exponent were analyzed for devices with varying contact spacings and at different high temperatures. The SCLC exponent, m, is in the range of 2≤m≤4 depending on the applied voltage range, revealing the existence of the trap states in the channel region. The findings of this work indicate that the charge injection, field-induced ionization, and trap states in the p-GaN channel are critical factors in the current transport of p-GaN/AlGaN/GaN heterostructure.
Impact of plasma-activated water on germination, growth, and production of green leafy vegetables
Authors: Chalise Roshan , Tamang Asish , Kattel Avash , Sharma Sangat , Basnet Suresh , Khanal Raju
Published: June 2024

In this work, we investigated the effects of plasma-activated water produced by atmospheric pressure air gliding arc discharge on the germination, growth, and production properties of green leafy vegetable seeds. Increasing the plasma activation time from 0 to 20 min resulted in notable changes in the physio-chemical properties of the water, including elevated levels of nitrate and nitrite, hydrogen peroxide, oxidation–reduction potential, total dissolved solids, and electrical conductivity, along with a decrease in pH. Our findings indicate that plasma-activated water significantly promotes germination, enhances seedling growth, and boosts the production of green leafy vegetables. The rate of water absorption by seeds increased with longer exposure times to plasma. Notably, seeds treated with plasma-activated water for 10–15 min exhibited longer root and shoot lengths, increased fresh weight of plants, and improved seed germination compared to the control group. Furthermore, the chlorophyll content in green leafy plants was enhanced when irrigated with plasma-activated water. However, prolonged exposure of seeds to plasma discharges for 20 min resulted in adverse effects on germination, growth, and production. These findings suggest that optimal plasma activation times are crucial in harnessing the beneficial effects of plasma-activated water on seed germination and plant growth.
Ground states of planar dipolar rotor chains with recurrent neural networks
Authors: Serwatka Tobias , Roy Pierre-Nicholas
Published: June 2024

In this contribution, we employ a recurrent neural network (RNN) architecture in a variational optimization to obtain the ground state of linear chains of planar, dipolar rotors. We test different local basis sets and discuss their impact on the sign structure of the many-body ground state wavefunction. It is demonstrated that the RNN ansatz we employ is able to treat systems with and without a sign problem in the ground state. For larger chains with up to 50 rotors, accurate properties, such as correlation functions and Binder parameters, are calculated. By employing quantum annealing, we show that precise entanglement properties can be obtained. All these properties allow one to identify a quantum phase transition between a paraelectric and a ferroelectric quantum phase.
Formation and stability of point defect color centers in 6H silicon carbide
Authors: Lemva Ousdal Erlend , Etzelmüller Bathen Marianne , Galeckas Augustinas , Kuznetsov Andrej , Vines Lasse
Published: June 2024

Point defect color centers acting as single-photon emitters are promising for quantum technology applications and have been extensively studied, e.g., in the 4H polytype of silicon carbide (SiC). However, the physics of such color centers in other SiC polytypes is much less explored. Herein, we study the formation and thermal stability of such color centers in 6H-SiC using photoluminescence spectroscopy. The emissions from typical single-photon emitters, such as silicon vacancies, divacancies, and carbon antisite-vacancy pairs in 6H-SiC, were monitored as a function of the proton irradiation fluence and post-irradiation annealing, and compared to that in 4H-SiC. Overall, at the background of similarities between the emission behavior in 4H- and 6H-SiC polytypes, we observed prominent differences; e.g., for the thermal stability of the carbon antisite-vacancy pair, which exhibited maximized emissions upon 300 and 900 °C anneals in 4H- and 6H-SiC, respectively. Moreover, we observed a range of defect emission signatures not previously reported for 6H-SiC in the literature and discussed their potential origin in the context of the thermal stability. For example, among the PL-lines in 6H-SiC, we detected periodically repeatable emission signatures, resembling the so-called L-lines recently reported in 4H-SiC, even though their exact origin has not yet been settled in the literature. Thus, we use color centers comparison in different polytypes to better understand the nature of the single-photon emitters in SiC.
Study of the effect of shock wave from a portable pulsed cold air plasma jet device on inactivation of Trichophyton rubrum in nails
Authors: Zhang Ying , Chen Zhaoquan , Shao Changsheng , Huang Qing
Published: June 2024

This study aimed to apply a portable pulsed cold air plasma jet (PP-CAPJ) device in onychomycosis treatment and investigate its effect and mechanism of action. Based on the characteristics of onychomycosis, we selected Trichophyton rubrum (T. rubrum) for our experiments and explored the inactivation ability of the PP-CAPJ on T. rubrum that grew in nails. We found that the PP-CAPJ could effectively kill T. rubrum in the nails, and for T. rubrum in 1.5 mm thick nails, 300 spark discharges could kill almost all the fungi. The fungicidal mechanism is mainly due to the ability of shock waves from the PP-CAPJ to impose pressure on the nail and destroy the cell membrane of T. rubrum. This work has therefore demonstrated the use of an effective and noninvasive approach for the treatment of onychomycosis.
Heterogeneous nucleation and growth of sessile chemically active droplets
Authors: Ziethen Noah , Zwicker David
Published: June 2024

Droplets are essential for spatially controlling biomolecules in cells. To work properly, cells need to control the emergence and morphology of droplets. On the one hand, driven chemical reactions can affect droplets profoundly. For instance, reactions can control how droplets nucleate and how large they grow. On the other hand, droplets coexist with various organelles and other structures inside cells, which could affect their nucleation and morphology. To understand the interplay of these two aspects, we study a continuous field theory of active phase separation. Our numerical simulations reveal that reactions suppress nucleation while attractive walls enhance it. Intriguingly, these two effects are coupled, leading to shapes that deviate substantially from the spherical caps predicted for passive systems. These distortions result from anisotropic fluxes responding to the boundary conditions dictated by the Young–Dupré equation. Interestingly, an electrostatic analogy of chemical reactions confirms these effects. We thus demonstrate how driven chemical reactions affect the emergence and morphology of droplets, which could be crucial for understanding biological cells and improving technical applications, e.g., in chemical engineering.
Modulation of the strength of weak S–H⋯O hydrogen-bond: Spectroscopic study of the complexes of 2-flurothiophenol with methanol and ethanol
Authors: Metya Surajit , Roy Supravat , Mandal Sourav , Huang Qian-Rui , Kuo Jer-Lai , Das Aloke
Published: June 2024

Spectroscopic exploration of sulfur-centered hydrogen bonding involving a thiol group (S–H) as the hydrogen bond donor is scarce in the literature. Herein, we have investigated 1:1 complexes of 2-fluorothiophenol (2-FTP) with methanol (MeOH) and ethanol (EtOH) in the gas phase to examine the physical characteristics and strength of the S–H⋯O hydrogen bond. Structures, conformations, and the strength of the S–H⋯O interaction are investigated by measuring the electronic and Infrared (IR) spectra of the two complexes employing resonant two-photon ionization, UV–UV hole-burning, and IR–UV double resonance spectroscopic techniques combined with quantum chemical calculations. Three conformers of 2-FTP⋯MeOH and two conformers of 2-FTP⋯EtOH have been detected in the experiment. A comparison of the IR spectra obtained from the experiment with those of the low-energy conformers of 2-FTP⋯MeOH and 2-FTP⋯EtOH predicted from the theory confirms that all the observed conformers of the two complexes are primarily S–H⋯O hydrogen bonded. The IR red-shifts found in the S–H stretching frequencies in 2-FTP⋯MeOH and 2-FTP⋯EtOH concerning that in 2-FTP are ∼76 and ∼88 cm−1, respectively, which are much larger than that was reported earlier in the 2-FTP⋯H2O complex (30 cm−1). The strength and physical nature of different noncovalent interactions, including the S–H⋯O hydrogen bond existing in the complexes, are further analyzed using natural bond orbital analysis, quantum theory of atoms in molecules, and localized molecular orbital-energy decomposition analysis. The current investigation reveals that the S–H⋯O hydrogen bond can be strengthened by judicial choices of the hydrogen bond acceptors of higher proton affinities.
Research on the diagnosis method of inter-turn short-circuit faults of dry-type air-core reactor winding based on frequency response analysis
Authors: Jin Shuo , E Yiyang , Zhu Lin , Li Chu , Yang Yuchen , Wu Ziwei
Published: June 2024

Inter-turn short circuit fault (ISCF) is the main fault type of dry-type air-core reactors (DARs), and the reactor burnout event caused by winding ISCF seriously threatens the safe and stable operation of the electric power system. In order to effectively curb the further worsening of ISCF in DARs, a fault detection method based on frequency response analysis was proposed. First, the effect of ISCF on the frequency response curve of the windings was investigated based on the distributed parameter model of DARs. Then, four sets of eigenvalues were proposed for ISCF diagnosis based on the influence law and curve data analysis theory. Finally, based on the eigenvalues, the support vector machine model optimized by the sparrow search algorithm was used to effectively classify the degree of ISCF of the reactor, and the accuracy reached 96%. Furthermore, a test platform was built based on the theoretical analysis for experimental verification, and the test results are consistent with the simulation results. Hence, the method proposed in this paper could effectively classify the ISCF and its severity in DARs. The research in this paper could provide effective guidance for the diagnosis of ISCF in DARs.
Irreducible Cartesian tensor decomposition: A computational approach
Authors: Bonvicini Andrea
Published: June 2024

Cartesian tensors are widely used in physics and chemistry, especially for the formulation of linear and nonlinear spectroscopies as well as for molecular response properties. In this work, we review the problem of irreducible Cartesian tensor (ICT) decomposition of a generic Cartesian tensor of rank n into its irreducible parts, each characterized by a specific symmetry. The matrix formulation of the ICT decomposition is structurally similar to the problem of rotational averaging using isotropic Cartesian tensors. Analogously to the latter, the ICT decomposition can be considered as a problem of selecting a set of permutations of n indices that provides a linearly independent set of mappings between Cartesian tensor subspaces. This selection can be performed using a simple computational approach based on the reduced row echelon form (rref) algorithm. This protocol has been implemented in a computer code used to re-derive the already known ICT decomposition for 2 ≤ n ≤ 4. Finally, for the first time, we performed the explicit ICT decomposition of a Cartesian tensor of rank n = 5.
Gain-driven synchronization and asymmetric bound states in the continuum within non-Hermitian circuit model
Authors: Zhang Chunlei , Kim Mun , Wang Jianbo , Hu Can-Ming
Published: June 2024

The gain-driven emission in gain–loss coupling systems attains significant interest. In this work, we study the monochromatic oscillation of a gain–loss coupling system through a circuit model, where the monochromacy is manifested as the gain-driven synchronization of two coupled oscillators. The synchronized oscillation in this model is theoretically studied and experimentally manifested. Benefiting from the conceptual simplicity of a circuit model, a pair of asymmetric long-living states is found among the unstable gain-driven monochromatic oscillations, corresponding to bound states in the continuum of coupling physics.
Anomalous supercurrent and diode effect in locally perturbed topological Josephson junctions
Authors: Fracassi Samuele , Traverso Simone , Traverso Ziani Niccolo , Carrega Matteo , Heun Stefan , Sassetti Maura
Published: June 2024

The simultaneous breaking of time-reversal and inversion symmetry can lead to peculiar effects in Josephson junctions, such as the anomalous Josephson effect or supercurrent rectification, which is a dissipationless analog of the diode effect. Due to their impact in new quantum technologies, it is important to find robust platforms and external means to manipulate the above-mentioned effects in a controlled way. Here, we theoretically consider a Josephson junction based on a quantum spin Hall system as the normal channel, subjected to a magnetic field in the direction defined by spin-momentum locking, and in the presence of a local tip in close proximity to one of the metallic edges in the normal region. We consider different local perturbations, model normal and magnetic tips, and study how they affect the Josephson response of the device. In particular, we argue that magnetic tips are a useful tool that allows for tunability of both ϕ0 response and supercurrent rectification.
Sputtering deposition of dense and low-resistive amorphous In2O3: Sn films under ZONE-T conditions of Thornton's structural diagram
Authors: Wada Yoshiharu , Magdy Wafaa , Takeda Keigo , Mido Yuta , Yamashita Naoto , Okumura Takamasa , Kamataki Kunihiro , Koga Kazunori , Hori Masaru , Shiratani Masaharu , Itagaki Naho
Published: June 2024

We have fabricated smooth-surfaced amorphous In2O3:Sn (a-ITO) films at a high temperature of 550 °C, far above the typical crystallization threshold of 150 °C for ITO films. This achievement has been made possible by intentionally introducing N2 into the sputtering atmosphere, which maintains a low N atom incorporation of only a few atomic percent within the films. Positioned within ZONE-T of the Thornton diagram (higher-temperature region characterized by high film density), our method allows the preparation of films with superior film density about 6.96 g/cm3, substantially exceeding the density of 6.58 g/cm3 for conventional a-ITO films fabricated under ZONE-1 (low-temperature region) and approaching the bulk crystal density of In2O3 at 7.12 g/cm3. The films also feature a high carrier density of 5 × 1020 cm−3 and a remarkably low resistivity of 3.5 × 10−4 Ω cm, comparable to those of polycrystalline films. The analysis via vacuum-ultraviolet absorption spectroscopy on N and O atom densities in the plasma suggests that amorphization is primarily caused not by N atoms incorporated in the films but by those temporally adsorbed on the film surface, inhibiting crystal nucleation before eventually desorbing. Our findings will pave the way not only for broader applications of a-ITO films but also for the design of other amorphous materials at temperatures beyond their crystallization points.
Error analysis of asymptotic solution of a heavy particle motion equation in fluid flows
Authors: Shen Chendong , Jin Guodong
Published: June 2024

For weakly inertial particles subjected to volumetric forces and Stokes drag force in fluid flows, we can solve the simplified particle motion equation using the perturbation method. This method allows us to obtain a recursive formula for the nth-order correction of the asymptotic solution of particle velocity. We verified the error of the asymptotic solution under two typical flow fields: a time-varying uniform flow field with a volumetric force field and a two-dimensional non-uniform cellular flow field. In the former, the relative error of the asymptotic solution of particle velocity and position increases with the Stokes number, and we provided a quantitative analysis of the results. In the latter, we verify and analyze the asymptotic solution from two perspectives: the behavior of a single particle and the collective behaviors of many particles. For asymptotic solutions with maximum velocity and position errors of less than 5%, we select the solution with the lowest order correction and designate it as the optimal asymptotic solution. The order of the optimal asymptotic solution increases with increasing Stokes numbers and motion durations. However, in most cases, for weakly inertial particles [St ∼ O(10−3)], and the time t* ∼ O(10), the first-order asymptotic solution can achieve accuracy, where both St and t* are defined using the flow field characteristic time, Tf = 4π s. The results validate the rationale behind utilizing first-order asymptotic solutions in the fast Eulerian method for turbulent dispersion of weakly inertial particles.
Analysis of depressive EEG signals via symbolic phase transfer entropy with an adaptive template method
Authors: Wang Hui , Zhang Qianxin , Luo Yuman , Wang Qiong , Zhu Shumei , Yi Wanyi , Wang Jun
Published: June 2024

Depression is a prevalent mental disorder in contemporary society. Symbolic phase transfer entropy can quantify the dynamic interaction and information flow between electroencephalogram (EEG) signals in depressed patients and healthy groups, which can help diagnose and treat depression. However, the traditional symbolization process of symbolic phase transfer entropy adopts the basic template method, which makes the symbolic phase transfer entropy unable to express the characteristics and changes of time series in different time periods in detail. Therefore, this paper proposes an improved symbolic phase transfer entropy algorithm, which adopts the adaptive template method in the symbolization process of the symbolic phase transfer entropy algorithm so that it can capture the dynamic changes of time series more finely. It was verified on the task EEG signals of 40 depressed patients and 40 healthy people. The experimental results show that the improved symbolic phase transfer entropy can more accurately distinguish depressed patients from healthy people in lead F4 and lead O1, which is helpful for the study of the EEG pathological characteristics of depression. The improved symbolic phase transfer entropy algorithm makes up for the shortcomings of the traditional symbolic phase transfer entropy in capturing the dynamic changes of time series and provides help for the study of dynamic changes in complex systems.
Theoretical studies and anharmonic effect analysis on the reaction mechanism of 3-methyl-1-butanol with OH radical
Authors: Wang Li , Chen Yiwei , Yao Li
Published: June 2024

The mechanism of hydrogen abstraction in the reaction of 3-methyl-1-butanol with an OH radical was investigated by quantum chemical calculations. The total reaction consists of five channels (R1–R5), with channel R3 having the lowest energy barrier (5.4 kcal·mol−1) and channel R4 having the highest energy barrier (13.2 kcal·mol−1). All channels are exothermic reactions with lower energy barriers. Thermodynamic parameters, including constant pressure molar heat capacity CPo, enthalpy of formation ΔfHo, and entropy So, for all reactants and products, were researched using the CBS-QB3 level across a temperature scale of 298–5000 K. The harmonic and anharmonic rate constants of all reaction channels were calculated at the CCSD(T)/6-311++G(d,p) level for a temperature range of 223–4000 K. Throughout the temperature range, except for R2, the harmonic rate constant of all reaction channels is consistently higher than the anharmonic one, and it can be seen from the results that the anharmonic effect is significant and cannot be ignored. Meanwhile, the polynomial coefficients a1–a7 for the thermodynamic parameters and the polynomial coefficients A, n, and E for the kinetic parameters were fitted using the principle of least squares.
Adsorption characteristics of Janus tadpole polymers
Authors: Vitecek Benedikt , Likos Christos N. , Gârlea Ioana C.
Published: June 2024

The shape of Janus particles is directly connected to their adsorption behavior. Janus tadpole polymers offer a unique topological architecture that includes competition between entropic, enthalpic, and topological terms in the adsorption free energy; accordingly, non-trivial adsorption behavior patterns are expected. We study the surface adsorption of Janus tadpole polymers by means of Monte Carlo simulations, finding that, depending on which part of the tadpole polymers is preferentially adsorbing on the surface, very different types of behavior for both the adsorbed polymeric phase and of the brush arise. The adsorbed phase and the brush mutually influence each other, leading to a variety of phenomena such as nematic ordering of the adsorbed stiff tadpole tails and intriguing changes in the territoriality of adsorbed ring polymers on the surface. We analyze in detail our findings, revealing the mechanisms behind the organization and ordering, and opening up new possibilities to tune and control the structure of such systems.
Flow-induced vibrations of a twistable two-tandem cylinder system across varied gap ratios
Authors: Wu Wenbo , Gu Runpeng , Hu Zhongming
Published: June 2024

This paper presents a simulation study on the flow-induced vibrations (FIVs) of a two-tandem cylinder system with three degrees of freedom, encompassing in-flow, cross-flow, and torsional motions at a Reynolds number of 150. We specifically focus on investigating the impact of gap ratios (G*) between the cylinders, considering values of 0.5, 2, and 3. The ratio of torsional natural frequency to translational natural frequency was maintained at 12.5, while the mass ratio between the cylinder system and the fluid was set to 2. Our findings reveal a notable sensitivity of the FIV responses to the gap ratio between the cylinders. It was observed that the cylinder system's vibrations can undergo locking phenomena at both the translational and torsional natural frequencies, with maximal cross-flow amplitudes occurring within the torsional locked region. Particularly, at G* = 0.5, the maximal cross-flow amplitude reached approximately 21.4 times that of the cylinder system without torsional vibration, posing potential risks of fatigue failure in offshore equipment. Conversely, at G* = 2, an unusual ultra-low frequency was detected in the in-flow vibration. This phenomenon significantly magnified the FIV of the cylinder system, despite the absence of frequency locking. Furthermore, at G* = 3, we observed an expanded range of vibrations with ultra-low frequency compared to G* = 2. Our analysis identified the differential development speed of the shear layers around the upstream and downstream cylinders as a key factor contributing to varying vortex shedding frequencies. This discrepancy led to periodic changes in the vortex shedding mode of the cylinder system over time, thereby introducing low-frequency components into the flow-induced vibration. These insights deepen our understanding of the complex dynamics governing the FIV of tandem cylinder systems, which holds implications for the design and maintenance of offshore structures.
Free-burning arc discharge simulation: The self-induced magnetic field analysis and its effect on arc plasma characteristics
Authors: Komaizi D. , Niknam A. R.
Published: June 2024

Free-burning arc discharges play important roles in physical processes such as cutting, welding, arc furnaces, and switchgear. Therefore, in this paper, a combination of node-based and edge-based finite-element methods with the finite-volume scheme is developed to investigate the dynamics of these arc discharges. Considering the significant effect of self-induced magnetic fields on the dynamics of the thermal plasma arcs, accurate analysis of these magnetic fields is essential, especially for 3D geometries describing realistic conditions. Accordingly, the edge-based finite-element module is utilized to study the Ampere law in its vector form for estimating the vector potential and the corresponding magnetic field. Furthermore, the current conservation equation is solved using the node-based finite-element technique. The fluid dynamics are also investigated with the well-known finite-volume method. This hybrid model gives more accurate magnetic fields and Lorentz forces. Electromagnetic forces create high-speed streams of thermal plasma and increase the pressure in the near regions of the electrodes. As a result, the pressure and velocity profiles are closer to the predicted results. In addition, the fluid flow changes the temperature distribution in a way that agrees with experimental measurements.
Juvenile social play predicts adult reproductive success in male bottlenose dolphins
Authors: Holmes Kathryn G. , Krützen Michael , Ridley Amanda R. , Allen Simon J. , Connor Richard C. , Gerber Livia , Flaherty Stamm Cindy , King Stephanie L.
Published: June 2024

For over a century, the evolution of animal play has sparked scientific curiosity. The prevalence of social play in juvenile mammals suggests that play is a beneficial behavior, potentially contributing to individual fitness. Yet evidence from wild animals supporting the long-hypothesized link between juvenile social play, adult behavior, and fitness remains limited. In Western Australia, adult male bottlenose dolphins (
Tursiops aduncus
) form multilevel alliances that are crucial for their reproductive success. A key adult mating behavior involves allied males using joint action to herd individual females. Juveniles of both sexes invest significant time in play that resembles adult herding—taking turns in mature male (actor) and female (receiver) roles. Using a 32-y dataset of individual-level association patterns, paternity success, and behavioral observations, we show that juvenile males with stronger social bonds are significantly more likely to engage in joint action when play-herding in actor roles. Juvenile males also monopolized the actor role and produced an adult male herding vocalization (“pops”) when playing with females. Notably, males who spent more time playing in the actor role as juveniles achieved more paternities as adults. These findings not only reveal that play behavior provides male dolphins with mating skill practice years before they sexually mature but also demonstrate in a wild animal population that juvenile social play predicts adult reproductive success.
The spillover effect of mandatory renewable portfolio standards
Authors: Zhou Shan , Solomon Barry D. , Brown Marilyn A.
Published: June 2024

Renewable Portfolio Standards (RPSs) are one of the most prevalent and impactful clean energy policies implemented by states in the United States. This paper investigates the regional spillover effect of RPS policies using a directed dyad panel dataset of renewable electricity generation in US states from 1991 to 2021. Regional spillover effect is measured in two ways: by considering the influence of an RPS enacted in neighboring states and in states in the same regional transmission organization or independent system operator region. We use dyadic fixed effects estimation and conclude that the neighboring state’s RPS stringency score is a strong determinant of a state’s total renewable electricity generation. For states without an RPS, the positive influence of an RPS in a neighboring state is larger when the non-RPS state has more abundant renewable energy resources than the neighboring RPS state. Our findings suggest that past RPS policy evaluation research using a confined within-state focus may have underestimated the holistic impact of an RPS, as the impacts of an RPS policy can extend beyond the enacting state’s borders. Overall, this study contributes to an improved understanding of the holistic impact of state RPS policies.
Thermoelectricity at a gallium–mercury liquid metal interface
Authors: Vernet Marlone , Fauve Stephan , Gissinger Christophe
Published: June 2024

We present experimental evidence of a thermoelectric effect at the interface between two liquid metals. Using superimposed layers of mercury and gallium in a cylindrical vessel operating at room temperature, we provide a direct measurement of the electric current generated by the presence of a thermal gradient along a liquid–liquid interface. At the interface between two liquids, temperature gradients induced by thermal convection lead to a complex geometry of electric currents, ultimately generating current densities near boundaries that are significantly higher than those observed in conventional solid-state thermoelectricity. When a magnetic field is applied to the experiment, an azimuthal shear flow, exhibiting opposite circulation in each layer, is generated. Depending on the value of the magnetic field, two different flow regimes are identified, in good agreement with a model based on the spatial distribution of thermoelectric currents, which has no equivalent in solid systems. Finally, we discuss various applications of this effect, such as the efficiency of liquid metal batteries.
KCNQ1 is an essential mediator of the sex-dependent perception of moderate cold temperatures
Authors: Kiper Aytug K. , Wegner Sven , Kadala Aklesso , Rinné Susanne , Schütte Sven , Winter Zoltán , Bertoune Mirjam A. R. , Touska Filip , Matschke Veronika , Wrobel Eva , Streit Anne-Kathrin , Lang Florian , Schmidt Constanze , Schulze-Bahr Eric , Schäfer Martin K.-H. , Voelkl Jakob , Seebohm Guiscard , Zimmermann Katharina , Decher Niels
Published: June 2024

Low temperatures and cooling agents like menthol induce cold sensation by activating the peripheral cold receptors TRPM8 and TRPA1, cation channels belonging to the TRP channel family, while the reduction of potassium currents provides an additional and/or synergistic mechanism of cold sensation. Despite extensive studies over the past decades to identify the molecular receptors that mediate thermosensation, cold sensation is still not fully understood and many cold-sensitive peripheral neurons do not express the well-established cold sensor TRPM8. We found that the voltage-gated potassium channel KCNQ1 (Kv7.1), which is defective in cardiac LQT1 syndrome, is, in addition to its known function in the heart, a highly relevant and sex-specific sensor of moderately cold temperatures. We found that KCNQ1 is expressed in skin and dorsal root ganglion neurons, is sensitive to menthol and cooling agents, and is highly sensitive to moderately cold temperatures, in a temperature range at which TRPM8 is not thermosensitive. C-fiber recordings from
KCNQ1
−/−
mice displayed altered action potential firing properties. Strikingly, only male
KCNQ1
−/−
mice showed substantial deficits in cold avoidance at moderately cold temperatures, with a strength of the phenotype similar to that observed in
TRPM8
−/−
animals. While sex-dependent differences in thermal sensitivity have been well documented in humans and mice,
KCNQ1
is the first gene reported to play a role in sex-specific temperature sensation. Moreover, we propose that KCNQ1, together with TRPM8, is a key instrumentalist that orchestrates the range and intensity of cold sensation.
Facet-switching of rate-determining step on copper in CO
2
-to-ethylene electroreduction
Authors: Zhang Yu-Cai , Zhang Xiao-Long , Wu Zhi-Zheng , Niu Zhuang-Zhuang , Chi Li-Ping , Gao Fei-Yue , Yang Peng-Peng , Wang Ye-Hua , Yu Peng-Cheng , Duanmu Jing-Wen , Sun Shu-Ping , Gao Min-Rui
Published: June 2024

Reduction of carbon dioxide (CO
2
) by renewable electricity to produce multicarbon chemicals, such as ethylene (C
2
H
4
), continues to be a challenge because of insufficient Faradaic efficiency, low production rates, and complex mechanistic pathways. Here, we report that the rate-determining steps (RDS) on common copper (Cu) surfaces diverge in CO
2
electroreduction, leading to distinct catalytic performances. Through a combination of experimental and computational studies, we reveal that C─C bond-making is the RDS on Cu(100), whereas the protonation of *CO with adsorbed water becomes rate-limiting on Cu(111) with a higher energy barrier. On an oxide-derived Cu(100)-dominant Cu catalyst, we reach a high C
2
H
4
Faradaic efficiency of 72%, partial current density of 359 mA cm
−2
, and long-term stability exceeding 100 h at 500 mA cm
−2
, greatly outperforming its Cu(111)-rich counterpart. We further demonstrate constant C
2
H
4
selectivity of >60% over 70 h in a membrane electrode assembly electrolyzer with a full-cell energy efficiency of 23.4%.
“It’s nothing serious, take it easy”
Authors: Jiang Qingsheng , Mao Yansheng , Wang Yihang
Published: June 2024

Prior studies have focused on the prevalence, causes and impacts of patients’ negative emotions during
doctor-patient communication. However, to date, there is a paucity of research focusing on doctors’ emotion-regulating strategies
and their effects on online medical consultation (OMC). In this connection, drawing on the concept of extrinsic emotion
regulation, this paper analyzes empirically the doctors’ strategies in regulating patients’ emotions and examines the effects
based on data from Dingxiang Yisheng, one of the largest online medical consultation platforms in China. It is
found that doctors deploy extensive discourse of relational work and diagnosis to regulate patients’ negative emotions. Comments
from patients not only reveal the effectiveness of doctors’ strategies in alleviating negative emotions but also showcase that
patients attribute the relief of their emotions to doctors’ expertise, attitude, response speed, and communication skills. All
these findings contribute to theoretical insights into emotion regulation and have practical implications for online
doctor-patient communication.
Discovering Love numbers through resonance excitation during extreme mass ratio inspirals
Authors: Avitan Shani , Brustein Ram , Sherf Yotam
Published: June 2024

General Relativity predicts that black holes (BHs) do not possess an internal structure and consequently cannot be excited. This leads to a specific prediction about the waveform of gravitational waves (GWs) which they emit during a binary BH inspiral and to the vanishing of their Love numbers. However, if astrophysical BHs do possess an internal structure, their Love numbers would no longer vanish, and they could be excited during an inspiral by the transfer of orbital energy. This would affect the orbital period and lead to an observable imprint on the emitted GWs waveform. The effect is enhanced if one of the binary companions is resonantly excited. We discuss the conditions for resonant excitation of a hypothetical internal structure of BHs and calculate the phase change of the GWs waveform that is induced due to such resonant excitation during intermediate- and extreme-mass-ratio inspirals. We then relate the phase change to the electric quadrupolar Love number of the larger companion, which is resonantly excited by its smaller companion. We discuss the statistical error on measuring the Love number by LISA and show that, because of this phase change, the statistical error is small even for values of the Love number as small as 10−4for moderate values of the spin parameter. Our results indicate that, for extreme-mass-ratio inspirals with moderate spin parameter, the Love number could be detected by LISA with an accuracy which is higher by up to two orders of magnitude than what can be achieved via tidal deformation effects. Thus, our results indicate that resonant excitation of the central BH during an extreme- or intermediate-mass-ratio inspirals is the most promising effect for putting bounds on, or detecting, non-vanishing tidal Love numbers of BHs.
Can a radiation gauge be horizon-locking?
Authors: Stein Leo C
Published: June 2024

In this short Note, I answer the titular question: yes, a radiation gauge can be horizon-locking. Radiation gauges are very common in black hole perturbation theory. It’s also very convenient if a gauge choice is horizon-locking, i.e. the location of the horizon is not moved by a linear metric perturbation. Therefore it is doubly convenient that a radiation gauge can be horizon-locking, when some simple criteria are satisfied. Though the calculation is straightforward, it seemed useful enough to warrant writing this Note. Finally I show an example: the

ℓ

vector of the Hartle–Hawking tetrad in Kerr satisfies all the conditions for ingoing radiation gauge to keep the future horizon fixed.
Comparative analysis of microstructure, electrical and optical performance in sidewall etching process for GaN-based green micro-LED
Authors: Li Xinran , Su Xujun , Wang Guobin , Chen Jingjing , Wang Luhua , Song Wentao , Xu Ke
Published: June 2024

Micro-LEDs show the size-dependent external quantum efficiency (EQE) reduction problem, mainly owing to increased non-radiative recombination loss at the sidewall for smaller chip size. In this work, the evolution of microstructure, surface potential and optical performance of the green micro-LED sidewall was investigated comparatively after inductively coupled plasma (ICP) and tetramethylammonium hydroxide (TMAH) etching through transmission electron microscopy (TEM), Kelvin probe force microscope (KPFM), cathodoluminescence (CL) and time-resolved photoluminescence (TRPL). As confirmed by TEM and geometric phase analysis (GPA), ICP etching causes sidewalls to form atomically rough semi-polar surfaces and increases 25% compressive strain at the sidewall compared to the inside. TMAH solution introduces new sidewall defects due to excessive etching of three atomic layers of InGaN. Holes accumulate at the surface because of build-in electric field as showed by KPFM. The sidewall defects lead to a decrease in carrier lifetime resulting in uneven luminescence of micro-LED mesa. TMAH treatment removes the damaged layer and reduces the non-radiative recombination rate. ICP causes damage to the nanoscale structure, however the influence of sidewall defects on the carrier behavior is in the micron range due to unavoidable surface dangling bonds and surface lattice relaxation. A non-radiative recombination mechanism is proposed based on strain relaxation.
Two-dimensional borophane semiconductor: a first-principles calculation
Authors: Zhang Mingxin , He Chaoyu , Zhong Jianxin
Published: June 2024

The experimentally synthesized graphene-type boron single layer (g-borophene) and its hydrogenated derivative (borophane in Cmmm symmetry) have been confirmed as normal metals, which are not appropriate for applications in the semiconductor field. Based on first-principles calculations, a new adsorption pattern (P6/mmm) with semiconducting feature has been proposed as a metastable phase for hydrogenated borophene. The results show that P6/mmm phase is both dynamically and mechanically stable. Its total energy is 4.829 eV atom−1, which is slightly higher than that of the ground state Cmmm configuration (4.858 eV atom−1). The HSE06-based band structures show that P6/mmm phase is a semiconductor with an indirect band gap of 1.86 eV and such a band gap can be effectively modulated by external strains. Our work shows that surface hydrogenation has the opportunity to induce a metal-insulator transition in two-dimensional borophene and provide a new two-dimensional semiconductor for potential applications in nano-electronic devices.
Polarization-multiplexed dual-band terahertz beam switching based on magneto-dielectric metasurfaces
Authors: Li Fan , Cheng Jie-Rong , Tan Zhi-Yu , Fan Fei , Chang Sheng-Jiang
Published: June 2024

Electrically tunable metasurfaces with pixel-level phase control are good candidates for dynamic manipulation of the beam direction in the terahertz band, which is a critical and highly desired technique for next generation communications. Yet the complex biasing, limited aperture and cross talk hinders its progress. In this study, we propose a magnetic-field-globally controlled metasurface for beam switching. The metasurface is composed of a bi-layer silicon metagrating on a magneto-optical substrate InSb. The beam direction is governed by two physical processes: the magnetically-controlled polarization and the polarization-controlled diffraction. By utilizing the circular dichroism and Faraday rotation effects in InSb, the metasurface can operate at two frequency bands. The beam is switched among four directions by properly choosing the magnetic field biasing and the frequency. This study offers a promising solution for beam management using magnetic field biasing and in a global manner.
Low-crystalline urchin-like CuCo2O4/rGO composite for high-performance supercapacitor
Authors: Wang Xiaoyan , Hu Mingxiang , Yao Zuofang , Yang Le
Published: June 2024

To meet the excellent capacity, power density and long lifespan for supercapacitors, developing advanced transition-metal oxide electrode materials is an important topic. Herein, we explored the effect of alkali source hydrolysis on the structural feature of CuCo2O4 during the growing process. It is found that urea with stronger hydrolysis ability leads to better morphology but larger crystalline grain size. Further, the grain size is decreased by introducing reduced graphene oxide (rGO). Consequently, the urea-derived CuCo2O4/rGO composite with urchin-like hierarchy configuration and small crystalline grain size provides a specific capacity of 1664 C g−1 at current density of 1 A g−1, and remains 65.3% of initial capacity when the current density increases to 30 A g−1. The symmetric supercapacitor achieves a high energy density (16 Wh kg−1 at 7200 W kg−1) and cycle stability (93.2% capacity retention after 10 000 cycles at 10 A g−1). This study highlights the inherent relation between the structural feature and synthesis condition.
Controllable optical tweezer and spanner in evanescent fields via a single plasmonic metasurface
Authors: Zheng Zhiyuan , Yu Ying
Published: June 2024

A dual-functional plasmonic metasurface is proposed to realize trapping and rotation of microparticles in evanescent fields by simply changing the polarization of incident light. The metasurface is constituted with subwavelength rectangular nanoslit that is perforated in an Au film on the glass substrate. Simulated near-field intensity distributions show that surface plasmon vortex with designed topological charge and focused point with enhanced intensity can be controllably generated in the center region of the designed metasurface by different circularly polarized lights. Calculated optical force and optical potential on a polystyrene sphere further demonstrate the good performances of rotating and trapping a microparticle with the generated vortex and focused surface plasmon polaritons. Moreover, two examples designed with different topological charges demonstrate the flexibility of these metasurfaces in tuning the rotation radius of microparticles. The advantages of the proposed metasurface in design flexibility, multifunctionality, and small size may provide new possibilities for applications of integrated optical manipulation devices and systems.
A theoretical model considering the photochemical and photothermal behavior of arc radiation-induced gassing materials ablation
Authors: Cao Weidong , Li Xingwen , Luo Chaojie , Wang Qian , Yin Jianning , Zhang Yanfeng , Zhuang Tao
Published: June 2024

In this study, we introduce a theoretical model designed to explore both the photochemical and photothermal behavior of arc plasma radiation-induced ablation in gassing materials. We employ time-dependent density functional theory to analyze the photochemical behavior, while reactive force field molecular dynamics are used to explore the photothermal behavior. The phenomena, behavior and consequences of valence shell electronic excitation are analyzed in terms of ultraviolet (UV) absorption, electron-hole distribution, and Mayer bond order. Based on the photochemical findings, we apply a periodic electric field that corresponds to the vibration frequency of the permanent dipole moment to simulate infrared radiation, and convert UV photon energy into atomic kinetic energy to analyze UV radiation. This atomic-scale insight into photothermal behavior enables us to identify the final composition of ablation gases, including H2, CO, H2O, NH3, as well as specific cyanides, amines, and hydrocarbons. The results of the theoretical model and physical properties indicate that the concentration of hydrogen-containing gases in the ablation gas significantly affects the arc extinguishing capabilities of different polymers. Finally, we propose modification schemes suitable for polymers in power circuit breakers, considering UV absorption and smoke black production. Additionally, we present the potential application of theoretical models for calculating the ablation rate, necessitating further in-depth re-search.
Impact of tin doping on charge carrier dynamics of a two-dimensional lead halide perovskite
Authors: Bhandari Sahil , Kundar Milon , Pal Suman Kalyan
Published: June 2024

Compositional engineering and doping of lead halide perovskites (LHPs) have emerged as promising methods to adjust the optical properties of these materials. Tin (Sn) doping, in particular, proves effective in achieving tunable band gaps, enhanced stability, high defect tolerance, and improved transport properties. However, the impact of tin doping on the photophysical properties of two-dimensional (2D) LHPs remains largely unexplored. This study investigates the optical properties, including excited state properties, of a Sn-doped 2D perovskite, utilizing various spectroscopic techniques. Our femtosecond transient absorption measurements reveal alterations in charge carrier dynamics within the 2D perovskite due to Sn doping. The doping leads to a significant reduction in charge carrier trapping, resulting in slower carrier recombination. Furthermore, Sn doping reduces the exciton binding energy, consequently decelerating exciton-exciton annihilation in the Sn-doped perovskite.