bluuebunny/crossref_metadata_2025 huggingface dataset:
Random multi-player games
Authors: Kontorovsky Natalia L. , Pinasco Juan Pablo , Vazquez Federico
Published: March 2022

The study of evolutionary games with pairwise local interactions has been of interest to many different disciplines. Also, local interactions with multiple opponents had been considered, although always for a fixed amount of players. In many situations, however, interactions between different numbers of players in each round could take place, and this case cannot be reduced to pairwise interactions. In this work, we formalize and generalize the definition of evolutionary stable strategy (ESS) to be able to include a scenario in which the game is played by two players with probability p and by three players with the complementary probability 1−p. We show the existence of equilibria in pure and mixed strategies depending on the probability p, on a concrete example of the duel–truel game. We find a range of p values for which the game has a mixed equilibrium and the proportion of players in each strategy depends on the particular value of p. We prove that each of these mixed equilibrium points is ESS. A more realistic way to study this dynamics with high-order interactions is to look at how it evolves in complex networks. We introduce and study an agent-based model on a network with a fixed number of nodes, which evolves as the replicator equation predicts. By studying the dynamics of this model on random networks, we find that the phase transitions between the pure and mixed equilibria depend on probability p and also on the mean degree of the network. We derive mean-field and pair approximation equations that give results in good agreement with simulations on different networks.
Ruthenium hydrides encapsulated in sol–gel glasses exhibit new ultrafast vibrational dynamics
Authors: Pyles Cynthia G. , Patrow Joel G. , Cheng Yukun , Tonks Ian A. , Massari Aaron M.
Published: March 2022

Vibrational dynamics were measured by IR pump–probe spectroscopy and two-dimensional IR spectroscopy for triruthenium dodecacarbonyl and the undecacarbonyl hydride that forms when it is encapsulated in an alumina sol–gel glass. For comparison, a triruthenium undecacarbonyl hydride salt was also synthesized and studied in neat solution to identify the potential influence of the confined solvent environment on the dynamics experienced by carbon monoxide ligands. The vibrational lifetime was found to be significantly decreased for both hydride species relative to the dodecacarbonyl compound. Conversely, spectral diffusion of the CO vibrations was measured to be faster for the parent compound. The most significant dynamic changes occurred upon transformation from the starting compound to the hydride, while only minor differences were observed between the dynamics of the freely dissolved and sol–gel encapsulated hydrides. The results suggest that the structural change to the hydride has the largest impact on the dynamics and that its improved catalytic properties likely do not originate from confined solvent effects.
Asymptotic behavior of localized disturbance in a viscous fluid flow down an incline
Authors: Kulikovskii A. , Zayko J.
Published: March 2022

We analytically solve the problem of the evolution of small-amplitude waves in a uniform flow of a viscous fluid down an inclined plane. The flow is described in a hydraulic approximation. The flow is supposed to be convectively unstable, and the waves arise as a result of an instantaneous external point disturbance. The solution is presented as a Fourier integral to which the steepest descent method is applied twice. The asymptotics of the growing waves is found analytically as a function of two spatial coordinates and time. We show that the region of growing perturbations is a segment of a circle, that its linear dimensions grow linearly with time, and that it is defined by the characteristics of a system of Saint-Venant differential equations.
The Soft Matter Kitchen: Improving the accessibility of rheology education and outreach through food materials
Authors: Nelson Arif Z.
Published: March 2022

Foods can serve as a universal route for the understanding and appreciation of rheologically complex materials. The Soft Matter Kitchen is an educational outreach project started during the COVID-19 pandemic that leverages food recipes and experiments that can be carried out at home to discuss concepts in soft matter and rheology. This educational article showcases two representative outreach demonstrations developed by The Soft Matter Kitchen with detailed instructions for reproduction by a presenter. The first demonstration introduces the concept of complex materials to clarify the definition of rheology by comparing the flow behavior of whipped cream and honey. The second demonstration introduces the concept of material microstructure affecting material properties and macroscale behavior using a simple experiment with cheesecake. By grounding the presentation of this knowledge in food materials with which the audience likely already has experience, the goals of this project are to accelerate the understanding of rheological concepts, increase awareness of rheology in everyday life, and promote the development of intuition for rheologically complex materials.
Oscillatory dynamics of immiscible liquids with high viscosity contrast in a rectangular Hele–Shaw channel
Authors: Kozlov Viktor , Vlasova Olga
Published: March 2022

The dynamics of the interface of liquids with a high viscosity contrast, performing harmonic oscillations with zero mean in a straight slot channel, is experimentally investigated. The boundary is located across the channel and oscillates along the channel with a harmonic change in the flow rate of the fluid pumped through the channel. Owing to the high contrast of viscosities, the motion of the more viscous liquid obeys Darcy's law, while the low-viscosity liquid performs “inviscid” oscillations. The oscillations of the interface occur in the form of an oscillating flat tongue of low-viscosity liquid that periodically penetrates into the more viscous one. The interface oscillations lead to the manifestation of two effects. One of these consists of changes in the averaged shape of the interface and the liquid contact line. The interface in the cell plane takes the form of a “hill,” the dynamical equilibrium of which is maintained by oscillations, while the deformation of the boundary is proportional to the amplitude of the oscillations and vanishes in their absence. The second effect consists of the development of finger instability of the oscillating boundary, which manifests itself in the periodic development of fingers of low-viscosity liquid at part of a period. The instability develops in a threshold manner when the relative amplitude of the interface oscillations reaches a critical value. It is found that the instability has a local character and manifests itself in those regions of the interface where the amplitude of the oscillations reaches a critical value. The stability threshold decreases with the dimensionless frequency.
A hybrid scheme coupling lattice Boltzmann method and finite-volume lattice Boltzmann method for steady incompressible flows
Authors: Wen Mengke , Li Weidong , Zhao Zhangyan
Published: March 2022

We present a new hybrid method coupling the adaptive mesh refinement lattice Boltzmann method (AMRLBM) and the finite-volume lattice Boltzmann method (FVLBM) to improve both the simulation efficiency and adaptivity for steady incompressible flows with complex geometries. The present method makes use of the domain decomposition, in which the FVLBM sub-domain is applied to the region adjacent to the walls, and is coupled to the lattice Boltzmann method (LBM) sub-domain in the rest of the flow field to enhance the ability of the LBM to deal with irregular geometries without sacrificing the high efficiency and accuracy property of the LBM. In the LBM sub-domain, a cell-centered lattice structure-based AMRLBM is used and, in the FVLBM sub-domain, the gas-kinetic Bhatnagar–Gross–Krook (BGK) scheme-based FVLBM is adopted to reduce the numerical dissipation and enhance the efficiency of FVLBM. Moreover, not like the conventional LBM and Navier–Stokes equation solver-based hybrid schemes, the present hybrid scheme combines two kinds of lattice Boltzmann equation solvers, that is, AMRLBM and FVLBM, which makes the present scheme much simpler and better consistency than the conventional hybrid schemes. To assess the accuracy and efficacy of the proposed method, various benchmark studies, including the Kovasznay flow, the lid-driven cavity flow with Reynolds number Re=100, 400, and 1000, and the steady flow past a cylinder with Re=20 and 40, are also conducted. The numerical results show that the present scheme can be an efficient and reliable method for steady incompressible flows.
Flux-based modeling of heat and mass transfer in multicomponent systems
Authors: Beris Antony N. , Jariwala Soham , Wagner Norman J.
Published: March 2022

In the present work, the macroscopic governing equations governing the heat and mass transfer for a general multicomponent system are derived via a systematic nonequilibrium thermodynamics framework. In contrast to previous approaches, the relative (with respect to the mass average velocity) component mass fluxes (relative species momenta) and the heat flux are treated explicitly, in complete analogy with the momentum flux. The framework followed here, in addition to allowing for the description of relaxation phenomena in heat and mass transfer, establishes to the fullest the analogy between all transport processes, momentum, heat, and mass transfer, toward which R. B. Bird contributed so much with his work. The inclusion of heat flux-based momentum as an additional variable allows for the description of relaxation phenomena in heat transfer as well as of mixed (Soret and Dufour) effects, coupling heat and mass transfer. The resulting models are Galilean invariant, thereby resolving a conundrum in the field, and always respect the second law of thermodynamics, for appropriate selection of transport parameters. The general flux-based dynamic equations reduce to the traditional transport equations in the limit when mass species and heat relaxation effects are negligible and are fully consistent with the equations established from the application of kinetic theory in the limit of dilute gases. As an added benefit, for the particular example case of hyperbolic diffusion we illustrate the application of the proposed models as a method to allow the use of powerful numerical solvers normally not available for solving mass transfer models more generally.
Fiber-form nanostructured tungsten formation by helium arc discharge plasma irradiation under a gas pressure of 5 kPa
Authors: Kikuchi Y. , Aota T. , Kadowaki K. , Tajima M. , Maenaka S. , Fujita K. , Takamura S.
Published: March 2022

Fiber-form nanostructured tungsten (W) formation was successfully demonstrated using a helium (He) arc discharge plasma generated at a gas pressure of 5 kPa. The W substrate was exposed to the He arc discharge plasma at a surface temperature of about 1000 °C. A bias voltage, Vb, was applied between the W substrate and the vacuum chamber to control the incident He ion energy, Ei. Scanning electron microscope (SEM) observations showed that the W surface was slightly roughened, but no fiber-form nanostructure was formed at a Vb of −22 V. On the other hand, fiber-form nanostructure growth was observed at a Vb of −112 V. Furthermore, cross-sectional SEM observations revealed the presence of He bubbles inside the W fibers and the sub-surface layer of the W substrate. As collisions between ions and neutrals in the sheath cannot be ignored at 5 kPa, a theoretical evaluation of Ei distribution was performed using the collisional sheath model. Furthermore, an experimental evaluation of Ei using the sputtering yield of carbon substrates by He arc discharge plasma irradiation was carried out, and then Ei was obtained to be 40–50 eV for Vb = −112 V. Therefore, the distribution of Ei at Vb = −112 V is considered to contain more than 20 eV, which is necessary for the growth of fiber-form nanostructured W found in conventional low-gas pressure plasma irradiation experiments.
On the proper periodic Ricker model
Authors: Cánovas Jose S.
Published: March 2022

The periodic Ricker equation has been studied by several authors, including the present one. However, the periodic model derived from the original one has not been studied in detail. We show that the model often taken as a periodic Ricker model is a particular case of the original one and compare their dynamics. In particular, we characterize the parameter region where the model has a periodic point of period two, which is globally stable. We also compute the parameter regions where complex behavior is exhibited.
A geometrical model of pinch-off in digital microfluidics underpins “one-to-three” droplet generation
Authors: Hu Chenxuan , Zhang Haoming , Jiang Chen , Ma Hanbin
Published: March 2022

Droplet generation is a fundamental sample handling procedure in digital microfluidics. In this work, a symmetric “one-to-three” droplet generation strategy is reported. A triangular model based on the geometrical relationship of reservoir droplets, sub-droplets, and liquid necks is proposed. Numerical investigation and corresponding experiments are performed. The results indicate that the proposed strategy produces a greater pressure difference for sub-droplet generation, especially when traditional droplet splitting is not possible with restricted microfluidics device geometries. The proposed geometrical model is a powerful tool to propose several improved droplet generation strategies. The “one-to-three” droplet generation strategy shows potential in practical applications and further studies for digital microfluidics platform.
Exploring the use of the pentaphenylcyclopentadienyl ligand in uranium chemistry: the crystal structure of (C
Authors: Wedal Justin C. , Ziller Joseph W. , Evans William J.
Published: March 2022

The reaction of UI3 with NaC5Ph5 in THF generated (η5-C5Ph5)UI2(THF)2 which was characterized by X-ray crystallography. The complex has a four-legged piano stool structure with a 2.539 Å U– (C5Ph5 ring centroid) distance that is slightly longer than the 2.504 Å distance in (η5-C5Me5)UI2(THF)3 which has a larger formal coordination number. Although the synthesis of the mono-cyclopentadienyl complex was facile, no bis-cyclopentadienyl complexes were isolated from reactions using two equivalents of the pentaphenylcyclopentadienyl ligand per uranium. In one UI3/2NaC5Ph5 synthesis, the X-ray crystal structure of (THF)3Na(η5-C5Ph5) was obtained. Attempts to reduce (η5-C5Ph5)UI2(THF)2 did not give evidence for a UII product. KC8 reductions of the in situ reaction of NdI3 and NaC5Ph5, analogous to the synthesis of (η5-C5Ph5)UI2(THF)2, yielded an X-ray crystal structure of a solvent-separated ion pair (SSIP), [K(18-crown-6)(THF)2][C5Ph5].
Non-Fermi liquid phase and linear-in-temperature scattering rate in overdoped two-dimensional Hubbard model
Authors: Wú Wéi , Wang Xiang , Tremblay André-Marie
Published: March 2022

Significance

Most metals display an electron-scattering rate1/τthat follows1/τ∼T2at low temperatures, as prescribed by Fermi liquid theory. But there are important exceptions. One of the most prominent examples is the “strange” metal regime in overdoped cuprate supercondcutors, which exhibits a linearTdependence of the scattering rate1/τ∼Tthat reaches a putative Planckian limit. Here, using cutting-edge computational approaches, we show thatT-linear scattering rate can emerge from the overdoped Hubbard model at low temperatures. Our results agree with cuprate experiments in various aspects but challenge the Planckian limit. Finally, by identifying antiferromagnetic fluctuations as the physical origin of theT-linear scattering rate, we discover the microscopic mechanism of strange metallicity in cuprates.
A mixed-valent Fe(II)Fe(III) species converts cysteine to an oxazolone/thioamide pair in methanobactin biosynthesis
Authors: Park Yun Ji , Jodts Richard J. , Slater Jeffrey W. , Reyes Reyvin M. , Winton Valerie J. , Montaser Rana A. , Thomas Paul M. , Dowdle William B. , Ruiz Anahi , Kelleher Neil L. , Bollinger J. Martin , Krebs Carsten , Hoffman Brian M. , Rosenzweig Amy C.
Published: March 2022

Significance

Methanobactins (Mbns), copper-binding peptidic compounds produced by some bacteria, are candidate therapeutics for human diseases of copper overload. The paired oxazolone-thioamide bidentate ligands of methanobactins are generated from cysteine residues in a precursor peptide, MbnA, by the MbnBC enzyme complex. MbnBC activity depends on the presence of iron and oxygen, but the catalytically active form has not been identified. Here, we provide evidence that a dinuclear Fe(II)Fe(III) center in MbnB, which is the only representative of a >13,000-member protein family to be characterized, is responsible for this reaction. These findings expand the known roles of diiron enzymes in biology and set the stage for mechanistic understanding, and ultimately engineering, of the MbnBC biosynthetic complex.
The syntax of directional Serial Verb Constructions in French-based creoles
Authors: Zribi-Hertz Anne , Jean-Louis Loïc
Published: March 2022

This article bears on directional Serial Verb Constructions (SVCs) in
French-based creoles. Starting with a working definition of our topic of study, we present a detailed description of the data in
Martinican Creole (MQ) – whose grammar is similar in the relevant respects to that of Haitian (HC). Four different structural
patterns are distinguished. Our results bring partial support to Aboh’s (2015)
assumption that the emergence of Haitian SVCs might have resulted from congruence between Gbe SVCs (analysed as ‘causative-like’)
and French Clause Union. We argue that this idea finds further confirmation in cross-creole comparison, but only concerns one type
of (directional) SVC.
L’oiseau-guide, de la mythologie indo-européenne à la fable du XIVe siècle
Authors: Redondo Jordi
Published: March 2022

Notre contribution vise à situer dans son contexte littéraire le symbolisme de l’oiseau-guide tel qu’on le trouve dans deux textes catalans caractérisés par leur étroit rapport avec la tradition occitane. Il s’agit des poèmes Frayre de joi e sor de plaser, anonyme, et de La faula de Guillem Torroella. Du point du vue aussi bien chronologique que formel, les deux poèmes offrent une composition parallèle. Le sujet dont il est question ici est la présence d’un oiseau qui guide le héros. Ce motif appartenant à la tradition poétique européenne, sa présence dans ces deux poèmes s’explique par la profonde influence de l’héritage mythologique sur les genres de la fable et le roman courtois. C’est ainsi que l’oiseau-guide se retrouve dans plusieurs récits français et occitans, notamment du cycle arthurien.
Infectious bursal disease.
Authors:   UK, CABI
Published: March 2022

Infectious bursal disease virus (IBDV), a double stranded RNA virus belonging to the genus Avibirnavirus and family Birnaviridae, is the causative agent of infectious bursal disease (IBD) (Luque et al., 2009). IBDV shows selective tropism for lymphoid tissues especially bursa of Fabricius and causes an acute and highly contagious viral disease which is manifested with inflammation and subsequently atrophy of the bursa of Fabricius, immunosuppression and various degrees of nephroso-nephritis in chickens between 3 weeks and 3 months of age (Berg, 2000; Eterradossi and Saif, 2008; Mahgoub, 2012; Müller et al., 2012). First recognized in Gumboro, Delaware (USA) in 1962, the disease was initially referred to as avian nephrosis, and later became known as Gumboro disease or infectious bursitis. Economic losses are high and are manifested in two ways. First, in the case of classical IBD, because of high mortality in chickens of 3-6 weeks and prolonged immunosuppression leading to secondary infections and vaccination failures (Ingrao et al., 2013). The virus occurs worldwide, and despite intensive vaccination regimes, outbreaks of disease occur frequently, and various variants of IBDV occur, each with a different virulence. At the end of the 1980s, very virulent variants of IBDV (vvIBDV) emerged, initially in Europe, and subsequently in Asia, the Middle East and South America. vvIBDV may cause acute disease in susceptible flocks over the entire growing period of broilers, in which the virus invades non-bursal and haematopoietic organs, such as the thymus, spleen and bone marrow. In many cases, the classical vaccines failed to provide sufficient protection against vvIBD (Fan et al., 2020). Thus novel vaccine technologies are being applied to design more effective vaccine and vaccination strategies against vvIBDV. The aim is to develop new, tailor-made live or inactivated (subunit) vaccines that protect against both classical and vvIBDV strains. They should have the potency of 'hot' live vaccines, without the accompanying dangers of causing immunosuppression. In particular the interference of maternal derived antibodies must be overcome. The development of marker vaccines that provide the ability to distinguish between vaccinal and infectious antibodies, would allow monitoring of the epidemiological field situation (Alkie and Rautenschlein, 2016).
Interface improvement of plasma cladded Ni-based coating on copper induced by substrate preheating
Authors: Zhang Chao , Wang Ruidong , Zhang Jun , Hu Rong , Lv Jinjin , Zhang Yuwen , Li Gaungshi , Lu Xionggang
Published: March 2022

To further clarify the characteristics of plasma cladding on copper surface, the effect mechanism of preheating temperature on the interfacial connection of Ni-based coatings was investigated. Results showed that metallurgical bonding can be achieved between coating and copper substrate only when the preheating temperature reached at least 500°C. Without preheating, the heat of the plasma arc was conducted away by the copper with high thermal conductivity, making it difficult to form a molten pool. At low temperatures (300°C and 400°C), the copper oxides formed on copper surface during preheating had poor wettability with the liquid Ni-based alloy, resulting in unreliable interfacial connection. Properly increasing (above 500°C) the preheating temperature can promote the removal of copper oxides, thereby improving the interfacial wettability. Moreover, to avoid performance degradation caused by excessive dilution ratio, controlling the preheating temperature at about 600°C is more appropriate.
mTORC2 suppresses cell death induced by hypo-osmotic stress by promoting sphingomyelin transport
Authors: Ono Yumiko , Matsuzawa Kenji , Ikenouchi Junichi
Published: March 2022

Epithelial cells are constantly exposed to osmotic stress. The influx of water molecules into the cell in a hypo-osmotic environment increases plasma membrane tension as it rapidly expands. Therefore, the plasma membrane must be supplied with membrane lipids since expansion beyond its elastic limit will cause the cell to rupture. However, the molecular mechanism to maintain a constant plasma membrane tension is not known. In this study, we found that the apical membrane selectively expands when epithelial cells are exposed to hypo-osmotic stress. This requires the activation of mTORC2, which enhances the transport of secretory vesicles containing sphingomyelin, the major lipid of the apical membrane. We further show that the mTORC2–Rab35 axis plays an essential role in the defense against hypotonic stress by promoting the degradation of the actin cortex through the up-regulation of PI(4,5)P2 metabolism, which facilitates the apical tethering of sphingomyelin-loaded vesicles to relieve plasma membrane tension.
Clathrin coated pits as signaling platforms for Akt signaling
Authors: Smythe Elizabeth
Published: March 2022

Signaling by the activated epidermal growth factor receptor (EGFR) results in diverse cell fates. In this issue, Cabral-Dias et al. (2022. J. Cell Biol.https://doi.org/10.1083/jcb.201808181) demonstrate how plasma membrane clathrin coated pits can act as a signaling platform for one branch of EGFR downstream signaling.
Transient astrocytic mGluR5 expression drives synaptic plasticity and subsequent chronic pain in mice
Authors: Danjo Yosuke , Shigetomi Eiji , Hirayama Yukiho J. , Kobayashi Kenji , Ishikawa Tatsuya , Fukazawa Yugo , Shibata Keisuke , Takanashi Kenta , Parajuli Bijay , Shinozaki Youichi , Kim Sun Kwang , Nabekura Junichi , Koizumi Schuichi
Published: March 2022

Activation of astrocytes has a profound effect on brain plasticity and is critical for the pathophysiology of several neurological disorders including neuropathic pain. Here, we show that metabotropic glutamate receptor 5 (mGluR5), which reemerges in astrocytes in a restricted time frame, is essential for these functions. Although mGluR5 is absent in healthy adult astrocytes, it transiently reemerges in astrocytes of the somatosensory cortex (S1). During a limited spatiotemporal time frame, astrocytic mGluR5 drives Ca2+ signals; upregulates multiple synaptogenic molecules such as Thrombospondin-1, Glypican-4, and Hevin; causes excess excitatory synaptogenesis; and produces persistent alteration of S1 neuronal activity, leading to mechanical allodynia. All of these events were abolished by the astrocyte-specific deletion of mGluR5. Astrocytes dynamically control synaptic plasticity by turning on and off a single molecule, mGluR5, which defines subsequent persistent brain functions, especially under pathological conditions.
Generalized inexact Newton regularization for nonlinear ill-posed problems in Banach spaces
Authors: Gu Ruixue , Fu Hongsun , Han Bo
Published: March 2022

In this paper, we generalize inexact Newton regularization methods to solve nonlinear inverse problems from a reflexive Banach space to a Banach space. The image space is not necessarily reflexive so that the method can be used to deal with various types of noise such as the Gaussian noise and the impulsive noise. The method consists of an outer Newton iteration and an inner scheme which provides increments by applying the regularization technique to the local linearized equations. Under some assumptions, in particular, the reflexivity of the image space is not required, we present a novel convergence analysis of the inexact Newton regularization method with inner scheme defined by Landweber iteration. Furthermore, by employing a two-point gradient method as inner regularization scheme to accelerate the convergence, we propose an accelerated version of inexact Newton–Landweber method and present the detailed convergence analysis. The numerical simulations are provided to demonstrate the effectiveness of the proposed methods in handling different kinds of noise and the fast convergence of the accelerated method.
A universal dimensionless length scale in medium range order amorphous structures
Authors: Shukla Pragya
Published: March 2022

Our theoretical analysis reveals the existence of a previously unknown universality, namely, a dimensionless length scale, related to a ratio of medium and short range order structures of amorphous systems that originates from a conspiracy between dispersion forces among molecules and their phonon mediated coupling. The scale in turn gives rise to the structure lying underneath the low temperature universalities of many other properties e.g. specific heat, internal friction, boson peak characteristics, Meissner–Berret ratio etc.
A modified fusion model-based/data-driven model for sensor fault diagnosis and performance degradation estimation of aero-engine
Authors: Huang Yufeng , Sun Gang , Tao Jun , Hu Yan , Yuan Liuyin
Published: March 2022

Sensor fault diagnosis and performance degradation estimation (SFDPDE) plays a critical role in the operation and maintenance of aero-engines. In this study, a modified fusion model driven by sensor measurements is proposed to overcome the drawbacks of the single data-driven and single model-based methods. Two types of on-board models are established based on augmented state space equations, and a data-driven model based on an extreme learning machine (ELM) is constructed for residual correction of the on-board model. A bidirectional information transmission algorithm is designed in the SFDPDE framework in order to include the function coordination. The Kalman filter is employed as the optimal algorithm in the SFDPDE framework, containing a standardized sensor parameter selection process. The experimental results indicate that the proposed fusion model improves the accuracy of sensor fault diagnosis and reduces the mean square error of health parameter estimations, while the information sharing module expands the application scope of SFDPDE and improves its accuracy as well as stability.
The catalytic effect of RuM-C catalyst attached to carbon- based support for hydrogen evolution reaction
Authors: Xu Ziqi , Liu Hui , Sun Jianhang , Zhou Weiying , Han Ce , Yang Guocheng , Shan Yuping
Published: March 2022

The potential of converting traditional biomass into low-cost HER catalysts has broad application prospects. In this paper, fungus is used as a carbon-based carrier. The bimetallic catalyst RuM-C (M = V, Mo, W, Zn, Cu) was synthesized under inert gas protection at high temperature. The order of electrocatalytic activity is RuV-C > RuZn-C > RuW-C > RuMo-C > Ru-C > RuCu-C > BF-C, which indicates that RuV-C exhibits excellent HER activity. Due to its irregular sheet structure, the specific surface area of the catalyst is increased. Impressively, it exhibits extremely high catalytic activity for HER in 1 M KOH due to favorable kinetics and excellent specific activity. Consequently, the prepared RuV-C exhibited excellent and stable HER activity compared Ru-C with a low overpotential of 65.78 mV at the current densities of 10 mA cm−2 and Tafel slope of 45.26 mV dec−1. The potential only decreased by 88 mV after 24 h of continuous testing, which indicates that the catalyst has outstanding stability. This work will provide positive inspiration for the promotion of a new Ru-based biomass HER electrocatalyst.
Periodical discharge regime transitions under long-term repetitive nanosecond pulses
Authors: Zhao Zheng , Li Chenjie , Zheng Xinlei , Sun Anbang , Li Jiangtao
Published: March 2022

Intuitively, the nanosecond repetitively pulsed (NRP) corona and spark regimes are sustained successively after onsets due to the high background electron density and/or the surplus heat. In this paper, the NRP discharge unexpectedly swings among different regimes (corona → glow → spark → corona → …) in one pulse train, which is characterized by the periodical spark quench and reestablishment. We have investigated discharge regime instabilities by applying long-term repetitive high-voltage nanosecond pulses of ∼15 ns duration to needle–needle and needle–plane gaps in atmospheric-pressure N2 and N2–O2 mixtures. Pulse-sequence resolved electrical and optical diagnostics have been implemented to capture transition processes. The initial corona gradually grows into glow and then spark ‘pulse-by-pulse’, however, the spark regime was interrupted after a certain number of voltage pulses until the next reestablishment. Narrow pulse width impedes the discharge instability growth within one pulse, and a certain number of voltage pulses are required for the discharge regime transition. The addition of O2 dramatically boosts the duration length of spark regime. A lower output impedance of the power supply induces a higher deposited energy into a spark, however, not necessarily leads to a longer spark regime duration, although both the energy storage and the average electric field strength are approximate. Polarity effects, conventionally diminished in pulse-periodic discharges, are still evident during the discharge regime transition. The periodical discharge regime transition is qualitatively explained based on the plasma–source coupling and the evolution trajectory along the power transfer curve. Feedback mechanisms and residual-conductivity related screening effect in NRP spark discharges are analyzed based on a simplified 0D simulation. The periodical feature is probably caused by the insufficient average deposited energy per unit distance per one pulse cycle. In-depth understandings of ‘non-binary’ regimes (neither corona nor spark) and memory effect mechanisms of NRP discharges could be reached.
Addendum: Experimental evidence of intrabeam scattering in a free-electron laser driver (2020 New J. Phys.

22 083053)
Authors: Di Mitri S , Perosa G , Brynes A , Setija I , Spampinati S , Williams P H , Wolski A , Allaria E , Brussaard S , Giannessi L , Penco G , Rebernik P R , Trov M
Published: March 2022

A conceptual inaccuracy in the calculation of energy spread induced by intrabeam scattering in the presence of linear acceleration is put in evidence. A new self-consistent equation is presented. Two new solutions are provided in the approximation of Coulomb logarithm independent of the particle energy, and for a weak energy dependence. A comparison of the three solutions is shown; it does not imply any noticeable modification to the previously published data, hence the published conclusions remain valid.
Role of deposition parameters on the properties of the fabricated heterojunction ZnS/p-Si Schottky diode
Authors: Kumar Arun , Mukherjee Samrat , Sharma Himanshu , Dwivedi Umesh Kumar , Kumar Sunil , Gangwar Rajesh K , Choubey Ravi Kant
Published: March 2022

Heterojunction diodes of ZnS/p-Si have been fabricated using the chemical bath deposition (CBD) technique at two different deposition durations under both stirring and non-stirring conditions. The x-ray diffraction (XRD) patterns indicate the deposited ZnS films exhibit good crystallinity with the growth direction along the (111) planes of a cubic zinc blend structure. The crystallite size of all the deposited ZnS thin films have been calculated using the Scherer formula and found to be in the range of 2.2–2.7 nm which is very close (∼4 nm) to the size estimated using transmission electron microscopy (TEM). The surface morphology of the deposited ZnS thin films were studied by scanning electron microscopy (SEM) and it was observed that spherical nanoparticles agglomerated with the increase in deposition time. Furthermore, the optical properties of the deposited ZnS thin films were studied using UV-visible (UV-VIS) and photoluminescence (PL) spectroscopy. The effective calculated band gap was found in the range from 3.7–3.82 eV for all the samples, however PL spectra shows multiple emissions in the as-deposited ZnS films, indicating the presence of intrinsic defects, The characteristics of the fabricated ZnS/p-Si heterojunction diode was studied by measuring the dark current-voltage (I–V) relation using thermionic emission model. Electrical parameters such as barrier height, saturation current, ideality factor and series resistance were extracted from the I–V characteristics of the fabricated Schottky diodes. The barrier potential for all the ZnS/p-Si heterojunction diodes range between 0.829–0.857. Moreover, the calculated ideality factor was found very close to the ideal value of the diode (1.34 and 1.43) in the devices fabricated under stirring conditions.
A comprehensive study of decay modes associated with Pb isotopes
Authors: Sharma R , Jain A , Sharma P K , Jain S K , Saxena G
Published: March 2022

Decay modes in Pb isotopes within the range 176 ≤ A ≤ 266 are investigated by the calculation of half-lives using several empirical formulas. These formulas along with various theoretical treatments are first tested to reproduce experimental half-lives and known decay modes of Pb isotopes, which are in consequence applied to estimate half-lives and decay modes of unknown Pb isotopes. A comparison between α-decay and weak-decay from the stable to drip-line isotopes is canvassed which leads to an excellent match with experimental data and applicability of applied empirical formulas. In addition, the full chain of Pb isotopes is probed as potential daughter candidates of cluster emission from superheavy nuclei which ensued the predominant role of 208Pb and nearby isotopes in probable cluster emission.
An infinite class of exact rotating black hole metrics of modified gravity
Authors: Afonso Victor I. , Mora-Pérez Gerardo , Olmo Gonzalo J. , Orazi Emanuele , Rubiera-Garcia Diego
Published: March 2022

We build an infinite class of exact axisymmetric solutions of a metric-affine gravity theory, namely, Eddington-inspired Born-Infeld gravity, coupled to an anisotropic fluid as a matter source. The solution-generating method employed is not unique of this theory but can be extended to other Ricci-Based Gravity theories (RBGs), a class of theories built out of contractions of the Ricci tensor with the metric. This method exploits a correspondence between the space of solutions of General Relativity and that of RBGs, and is independent of the symmetries of the problem. For the particular case in which the fluid is identified with non-linear electromagnetic fields we explicitly derive the corresponding axisymmetric solutions. Finally, we use this result to work out the counterpart of the Kerr-Newman black hole when Maxwell electrodynamics is set on the metric-affine side. Our results open up an exciting new avenue for testing new gravitational phenomenology in the fields of gravitational waves and shadows out of rotating black holes.
On the primordial correlation of gravitons with gauge fields
Authors: Jain Rajeev Kumar , Sai P. Jishnu , Sloth Martin S.
Published: March 2022

We calculate the primordial correlation of gravitons with an abelian gauge field non-minimally coupled through a dynamical dilaton field or a volume moduli during inflation in the early universe. In particular, we compute the cross-correlation of a tensor mode with two gauge field modes and the corresponding correlation functions for the associated magnetic and electric fields using the in-in formalism. Moreover, using semi-classical methods, we show that the three-point cross-correlation functions satisfy new consistency relations (soft theorems) in the squeezed limit. Our findings exhibit a complete agreement of the full in-in results with the new consistency relations.
An interesting consequence of our scenario is the possibility of a novel correlation of the primordial tensor mode with the primordial curvature perturbation induced by higher order quantum gravity corrections. The anisotropic background created by long wavelength gauge field modes makes this correlation function non-vanishing. Finally, we discuss how these three-point correlation functions are imprinted on cosmological observables today and the applications to scenarios of inflationary magnetogenesis.
Role of the zonal flow in multi-scale multi-mode turbulence with small-scale shear flow in tokamak plasmas
Authors: Li Hui , Li Jiquan , Wang Zhengxiong , Wei Lai , Hu Zhaoqing
Published: March 2022

The structural characteristics of zonal flows and their roles in the nonlinear interaction of multi-scale multi-mode turbulence are investigated numerically via a self-consistent Landau-fluid model. The multi-mode turbulence here is composed of a shorter wavelength electromagnetic (EM) ion temperature gradient (ITG) mode and a Kelvin–Helmholtz (KH) instability with long wavelengths excited by externally imposed small-scale shear flows. For strong shear flow, a prominent periodic intermittency of fluctuation intensity except for dominant ITG component is revealed in turbulence evolution, which onset time depends on the ion temperature gradient and the shear flow amplitudes corresponding to different KH instabilities. It is identified that the intermittency phenomenon results from the zonal flow dynamics, which is mainly generated by the KH mode and back-reacts on it. It is demonstrated that the odd symmetric components of zonal flow (same symmetry as the external flow) make the radial parity of the KH mode alteration through adjusting the drift velocities at two sides of the resonant surface so that the KH mode becomes bursty first. Afterwards, the ITG intermittency follows due to nonlinear mode coupling. Parametric dependences of the features of the intermittency are elaborated. Finally, associated turbulent heat transport is evaluated.
Effects of mesoscale eddies on the spatial coherence of a middle range sound field in deep water
Authors: Gao Fei , Xu Fang-Hua , Li Zheng-Lin
Published: March 2022

Mesoscale eddies have a remarkable influence on the underwater sound field. Many previous studies have investigated the effects of eddies on transmission loss, the convergence zone, time delay, etc. However, the effects of eddies on spatial coherence are less well studied and remain unclear. In this paper, the effects of eddies on spatial coherence at the subsurface in deep water are investigated. The eddy environments are simulated with Gaussian eddy equations, the complex pressure field is obtained using a range-dependent parabolic equation model and the associated mechanism is analyzed based on ray theory and models. The results show that cold/warm mesoscale eddies affect spatial coherence in a high-intensity zone by changing the locations and width of the convergence zone. In the shadow zone, the horizontal correlation radius and the vertical correlation radius increase with range and decrease with depth, and they are increased by warm eddies and decreased by cold eddies, mainly caused by variation of the multipath structure.
Spinal cord bioelectronic interfaces: opportunities in neural recording and clinical challenges
Authors: Jiang Lei , Woodington Ben , Carnicer-Lombarte Alejandro , Malliaras George , Barone Damiano G
Published: March 2022

Bioelectronic stimulation of the spinal cord has demonstrated significant progress in the restoration of motor function in spinal cord injury (SCI). The proximal, uninjured spinal cord presents a viable target for the recording and generation of control signals to drive targeted stimulation. Signals have been directly recorded from the spinal cord in behaving animals and correlated with limb kinematics. Advances in flexible materials, electrode impedance and signal analysis will allow spinal cord recording (SCR) to be used in next-generation neuroprosthetics. In this review, we summarize the technological advances enabling progress in SCR and describe systematically the clinical challenges facing spinal cord bioelectronic interfaces and potential solutions, from device manufacture, surgical implantation to chronic effects of foreign body reaction and stress–strain mismatches between electrodes and neural tissue. Finally, we establish our vision of bi-directional closed-loop spinal cord bioelectronic bypass interfaces that enable the communication of disrupted sensory signals and restoration of motor function in SCI.
A finite element method framework to model extracellular neural stimulation
Authors: Fellner Andreas , Heshmat Amirreza , Werginz Paul , Rattay Frank
Published: March 2022

Objective. Increasing complexity in extracellular stimulation experiments and neural implant design also requires realistic computer simulations capable of modeling the neural activity of nerve cells under the influence of an electrical stimulus. Classical model approaches are often based on simplifications, are not able to correctly calculate the electric field generated by complex electrode designs, and do not consider electrical effects of the cell on its surrounding. A more accurate approach is the finite element method (FEM), which provides necessary techniques to solve the Poisson equation for complex geometries under consideration of electrical tissue properties. Especially in situations where neurons experience large and non-symmetric extracellular potential gradients, a FEM solution that implements the cell membrane model can improve the computer simulation results. To investigate the response of neurons in an electric field generated by complex electrode designs, a FEM framework for extracellular stimulation was developed in COMSOL. Approach. Methods to implement morphologically- and biophysically-detailed neurons including active Hodgkin-Huxley (HH) cell membrane dynamics as well as the stimulation setup are described in detail. Covered methods are (a) development of cell and electrode geometries including meshing strategies, (b) assignment of physics for the conducting spaces and the realization of active electrodes, (c) implementation of the HH model, and (d) coupling of the physics to get a fully described model. Main results. Several implementation examples are briefly presented: (a) a full FEM implementation of a HH model cell stimulated with a honeycomb electrode, (b) the electric field of a cochlear electrode placed inside the cochlea, and (c) a proof of concept implementation of a detailed double-cable cell membrane model for myelinated nerve fibers. Significance. The presented concepts and methods provide basic and advanced techniques to realize a full FEM framework for innovative studies of neural excitation in response to extracellular stimulation.
Experimental investigation of L- and H-mode detachment via the divertor Thomson scattering at ASDEX Upgrade
Authors: Cavedon M. , Kurzan B. , Bernert M. , Brida D. , Dux R. , Griener M. , Henderson S. , Huett E. , Nishizawa T. , Lunt T. , Pan O. , Stroth U. , Wischmeier M. , Wolfrum E. , the ASDEX Upgrade Team
Published: March 2022

The capabilities of the newly installed divertor Thomson Scattering (DTS) diagnostic (Kurzan et al 2021 J. Inst.
16 C09012) at ASDEX Upgrade (AUG) have been demonstrated by measuring 2D electron densities n
e and temperatures T
e from attached to fully detached divertor conditions in L- and H-mode. The collected dataset is a breakthrough for divertor studies at AUG in which such measurements have been so far missing. Besides highlighting the strengths and limits of the DTS system, this work provides confirmations and new insights into detachment physics. The transition between partial and pronounced detachment correlates with a 2D redistribution of the electron density from the inner to the outer divertor in both L- and H-mode. In pronounced detachment, a strong parallel pressure gradient could be confirmed throughout the complete SOL. Finally, measurements of n
e and T
e of a stable X-point radiator revealed local temperatures as low as 1 eV within the confined plasma, whereas the pressure is shown to be constant on closed field lines.