bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of subtetanic neuromuscular electrical stimulation on sprint
interval exercise
Authors: Takeda Ryosuke , Nojima Hiroya , Nishikawa Taichi , Watanabe Kohei
Published: November 2024

The study aimed to determine the acute effects of subtetanic neuromuscular
electrical stimulation (NMES) combined with active recovery between sprint
exercises on blood lactate accumulation, sprint performance, and muscle fatigue.
Sixteen healthy young individuals [23(4) years, 10 males] underwent a 1-min rest
followed by sprint interval training consisting of four 15-sec maximal sprint
exercises with three 5-min active cycling sessions. Participants engaged in
voluntary cycling at 40% of peak oxygen consumption, with or without NMES (VOLES
or VOL; interventions). Blood lactate concentration ([La]b) was
assessed at the end of the rest and each intervention periods. Mean power was
assessed during each sprint exercise session. Maximum voluntary contraction
(MVC) of the knee extensor was measured before and after sprint interval
training to evaluate muscle fatigue. The [La]b was significantly
higher in VOLES than in VOL (main effect, P=0.037). Mean power did not differ
between conditions (main effect and interaction, P>0.050). MVC after sprint
interval exercise was significantly lower in VOLES than in VOL (interaction,
P<0.001). Subtetanic NMES combined with voluntary cycling enhanced blood
lactate accumulation and induced greater voluntary fatigue but resulted in
similar peripheral muscle fatigue and sprint exercise performance compared with
voluntary cycling without NMES.
Achieving Sustainability in the Assembly of Modified Nucleosides Using Green Solvents
Authors: Kudalkar Mahadev V. , Patel Manisha A. , Sanghvi Yogesh S. , Kapdi Anant R.
Published: November 2024

Chemical modifications of nucleosides have been a topic of special interest for researchers, given the plethora of applications these structural motifs have been able to demonstrate. For decades, such modifications have been performed in conventional volatile organic solvents that have severe environmental implications. A recent trend suggests a shift in the strategy, with many researchers using sustainable and green solvents such as ionic liquids (ILs), H2O, deep eutectic solvents (DES), and 2-MeTHF for performing key transformations on the nucleoside’s structural motif. This review critically analyzes examples of nucleoside functionalization carried out in different sustainable solvents and also helps to assess the feasibility of such solvent choices for further applications.
Proximal Ulnar Reinsertion of the Triceps Brachii Tendon with a Synthetic Implant in a Dog with Nonreconstructible Olecranon Fracture
Authors: Etchart Ninon , Estoueigt Elsa , Crumière Antonin , Goin Bastien , Jacques David
Published: November 2024

Objective Reporting the reinsertion of the triceps brachii onto the proximal ulna as a salvage procedure in a dog with nonreconstructible olecranon fracture.

Case Description A Labrador Retriever was presented with a comminuted olecranon fracture. Initial fracture stabilization was unsuccessful, resulting in implant failure and a nonreconstructible comminuted fracture, thus preventing triceps tendon reattachment. Revision surgery was performed after the implants and bone fragments were removed. A synthetic implant was sutured onto the triceps tendon and fixed on the proximal ulna by an interference screw (IS) in a bone tunnel. A transarticular Jean-Alphonse Meynard external fixator was applied for 3 weeks.

Results After 3 weeks, the dog had moderate lameness with a painless elbow. At 1.5 months, it had severe lameness with a painful elbow and mild osteoarthritis (OA). Nonsteroidal anti-inflammatory drugs were prescribed, and intensive physical therapy was initiated. Lameness improved at 2.5 and 3.5 months despite mild OA. At 9 months, the dog had mild lameness and a swelling of the elbow. Radiographs showed moderate OA and lucency around the IS. Bacteriologic examination was positive. The implants and infected tissues were removed, and antibiotics were prescribed for 1 month. At 18 months, the dog had mild lameness with no pain. At 33 months, it had intermittent mild lameness with no pain, yet severe OA.

Conclusion Triceps tendon re-insertion onto the proximal ulna yielded satisfactory long-term outcome in this dog with nonreconstructible olecranon fracture.
Woman on board, corporate social responsibility and financial performance: new evidence from China
Authors: Long Xianyi , Bu Xuelin , Xie Peng , Shao Yunwei
Published: November 2024

There are mixed findings on the impact of women directors on board (WOB) on corporate financial performance (CFP). To reconcile these mixed findings, we propose that WOB could influence CFP in the following two ways. On the one hand, WOB could enhance CFP by leading more CSR activities. On the other hand, WOB may weaken the CSR-CFP relationship due to expectations on their role-playing. These two effects go in opposite directions, and their relative strength determines the WOB-CFP relationship. Using Chinese listed firms from 2011 to 2020 as samples, the results lend strong support to these two effects. And WOB will have a positive effect on CFP only if its moderating effect on the CSR-CFP relationship has been controlled for. Additional tests show that neither critical mass nor qualification of women directors matters in explaining variations of CFP in Chinese firms. The contributions and limitations are discussed at the end of this study.
Effect of impurities on thermodynamic and kinetic properties of systems with electron–hole pairing
Authors: Bezuglyi A. I. , Shevchenko S. I.
Published: November 2024

It is shown that the pairing of electrons and holes belonging to different space regions can be suppressed by neutral impurities (and crystal structure defects) of sufficient concentrations. An exception is the case when electrons and holes of equal effective masses are scattered by impurity centers in the dielectric layer. The linear response of the system to dc and ac electromagnetic fields is calculated. Even in the presence of impurities the system retains coherent properties, particularly anomalous diamagnetism.
Electromagnetic generation of sound in metals under cyclotron resonance conditions
Authors: Fal’ko V. L. , Yampol’skii V. A.
Published: November 2024

The problem of the transformation of an electromagnetic wave into a sound wave under cyclotron resonance conditions is solved. It is shown that the nature of the scattering of electrons at the surface of a metal significantly affects the amplitude dependence of the sound on the magnetic field U(H). In the case of diffuse scattering, the amplitude experiences resonance in the region of intersection of the sound and transverse cyclotron wave spectra, and in the case of specular reflection the amplitude in the principal approximation depends monotonically on the magnetic field. In both cases, cyclotron and geometric resonance with small amplitude of U(H) should be observed.
Theory of the current-voltage characteristics of N-S structures subjected to the action of laser irradiation
Authors: Karas' V. I. , Moiseev S. S. , Novikov V. E. , Seminozhenko V. P.
Published: November 2024

The effect of intense laser irradiation on the current in N-I-S and N-V-N(S) systems is considered (N is a normal metal, S is a superconductor, I is an insulator and V is a vacuum), in the case of the direct action of irradiation on the N-metal. It is shown that with sufficient intensity of the laser radiation, the effect of “blocking” of the tunnel current on the current-voltage characteristics (CVC) of an N-I-S contact should be observed, over the range of voltages eV≳Ω(Ω is the frequency of the laser radiation). The “activation” structure of the CVC of N-V-N(S) systems also is predicted. The possibility is considered for reconstructing the parameters of a nonequilibrium electron distribution according to the form of the CVC.
Magnetic properties of zinc and of cadmium alloys with magnesium and with mercury
Authors: Svechkarev I. V. , Kuz'micheva L. B. , Poltoratskii V. I.
Published: November 2024

A study was made concerning the magnetic susceptibility of single crystals of binary cadmium-magnesium and cadmium-mercury alloys, within the range of existence of disordered solid solutions and of ternary cadmium-magnesium-mercury alloys, the temperature-susceptibility characteristics of these alloys over the 4.2–300°K range, and also the effect of uniaxial elastic strains and dislocations on the anisotropy of the magnetic susceptibility of zinc. From the anomalies of the magnetic susceptibility the locations of the critical points in the cadmium spectrum were then determined, and the separation between bands responsible for the magnetic properties was calculated. Owing to the smallness of this separation, the magnitude of the magnetic field intensity was found to affect appreciably the monotone component of the electron susceptibility. The nature of the influence which the temperature and the impurities have on the structure of the cadmium spectrum is analyzed here, and the scattering of electrons by the mercury impurity is evaluated.
Tunnel contacts in superconductors with a paramagnetic impurity
Authors: Moskalenko V. A. , Nika Yu. N.
Published: November 2024

It is shown that a paramagnetic impurity eliminates logarithmic divergences and amplitude discontinuities in the tunnel current through a contact formed by superconductors separated by a dielectric film. The presence of the impurity leads to the disappearance of singularities in the first derivatives of the amplitudes of Josephson, quasiparticle, and interference currents, although the second derivatives retain the singularities characteristic of pure superconductors. The relationship between several tunnel characteristics and kinetic characteristics of massive superconductors is demonstrated. The current amplitudes are calculated at the low impurity concentration limit for a voltage across the contact equal to ωg±ωg′ where ωg is the energy gap.
High-frequency conductivity of thin single-crystal tungsten wafers in a strong magnetic field
Authors: Mitryaev A. A. , Panchenko O. A.
Published: November 2024

The surface impedance Z = R +jX (over the 5−10 MHz frequency range) and the static resistivity ρ of thin single-crystal tungsten wafers were studied in relation to the intensity of an external magnetic field and to the surface state of a specimen. The experiments were performed at liquid-helium temperature with wafers which had been cleaned and stored under high vacuum. The changes in Z and ρ which occur with increasing surface purity are interpreted here as a result of an increase in the specularity for conduction electrons interacting with the crystal boundary.
Properties of superconducting microbridges in the pure limit
Authors: Kulik I. O. , Omel'yanchuk A. N.
Published: November 2024

An exact solution of Eilenberger's equations for a superconducting microbridge in the limit a ≪ ξ0, a ≪ l is given (a is the radius of the constriction between the superconductors, l is the mean free path and ξ0 is the coherence length). The current is independent of the ratio between l and ξ0 is expressed in terms of the contact resistance in the normal state. When T = 0, the magnitude of the critical current exceeds the critical current of the tunnel contact with the same resistance, by a factor of two.
Effect of magnetic impurities and pressure on the critical temperature of a superconductor with an AuGa2-type band structure
Authors: Palistrant M. E. , Trifan A. T.
Published: November 2024

The dependence of the critical temperature of the intermetallic compound AuGa2 on pressure and on the concentration of a magnetic impurity is studied here on the basis of the Lifshits model of an electronic transition. The dependence of the critical impurity concentration on the pressure and on the valence difference between impurity and host atoms is also studied.
Magnetic quantization in layered crystals
Authors: Maslyuk V. T. , Bercha D. M.
Published: November 2024

Quantization of the energy spectrum of layered crystals is investigated using the effective Hamiltonian method for magnetic fields directed along the plane of the layers. In this case the Schrödinger equation is shown to reduce the Mathieu equation the eigenvalues of which have a tendency to broaden for relatively large quantum numbers. The magnetic susceptibility is calculated for the magnetic field oriented along and perpendicularly to the layers.
Stochastic homogenization for wave equation with random potential and non-periodic coefficients
Authors: Su Dong
Published: November 2024

This paper is concerned with stochastic homogenization for wave equation with random potential and non-periodic coefficients. First, we show the stochastic homogenization for deterministic wave equation with random potential and non-periodic coefficients by the stochastic two-scale convergence approach. Then, we present the stochastic homogenization for stochastic wave equation with random potential and non-periodic coefficients by the similar approach.
On a solution to the Dirac equation with a triangular potential well
Authors: Payod Renebeth B. , Saroka Vasil A.
Published: November 2024

Chiral anomalies resulting from the breaking of classical symmetries at the quantum level are fundamental to quantum field theory and gaining ever-growing importance in the description of topological materials in condensed matter physics. Here we present analytical solutions of the Dirac equation for massless 3 + 1 fermions confined to an infinite stripe and placed into a background gauge field forming a triangular potential well across the width of the stripe. Such an effective 1 + 1 system hosts zero-energy modes resulting in the gauge field-dependent chiral anomaly structure. This problem has a direct relation to a half-bearded graphene nanoribbon placed into an in-plane external electric field and offers it an exact solution in terms of new special functions that are similar but not reducible to Airy functions.
A mathematical model for predicting the electro-mechanical behavior of biomimetic crack sensors: Effect of crack depth and gap
Authors: Song Ziming , Li Qi , Yan Yabin , Gao Yang , Xuan Fuzhen
Published: November 2024

Various biomimetic microstructures, such as porous, cracks, wrinkles, micro-pyramids, and micro-domes, are applied to improve the sensing performance of mechanical sensors. Among them, the crack-based strain sensors are widely investigated due to high sensitivity and fast response time. To clearly describe the relationship between crack morphology and sensor sensitivity, a mathematical model is developed for investigating the performance of a poly(3,4-ethylenedioxythiophene)-silicon oxide/polydimethylsiloxane (SiOx/PDMS) based crack strain sensor. First, the displacement field of a crack tip is calculated based on the theory of fracture mechanics, and the mathematical relationship between the crack depth, crack gap, and strain is obtained. The predicted crack depth of the SiOx thin film's thicknesses in 7.91 μm (SiOx/PDMS-7.91) is 2.82 μm, with the error of 3.75% compared to the experimental result. Correspondingly, the deviation of SiOx/PDMS-7.91 is 5.74% between the predicted crack gap and the experimental data. Second, above the aforementioned crack tip characteristics, the mathematical model based on crack edges contacts probability (CECP) is used to construct the relationship between the crack tip characteristics, applied stress, and device sensitivity. The maximum predicted sensitivity can reach 3562.68 compared with the experimental data of 3800.44, and the deviation is about 6.26%. Moreover, the CECP model has good universality with the other reported crack-based strain sensors. It can be concluded that crack morphology affects the distribution and quantity of conductive paths. When the strain sensor is subjected to external forces, brittle thin films generate a certain number of bumped-like elements for microcracks. The wider and deeper crack will increase the relative resistance change and the decrease of conductive paths, resulting in a rapid increase in the sensitivity of the strain sensor.
A high-throughput and data-driven computational framework for novel quantum materials
Authors: Kastuar Srihari M. , Rzepa Christopher , Rangarajan Srinivas , Ekuma Chinedu E.
Published: November 2024

Two-dimensional layered materials, such as transition metal dichalcogenides (TMDs), possess an intrinsic van der Waals gap at the layer interface, allowing for remarkable tunability of the optoelectronic features via external intercalation of foreign guests such as atoms, ions, or molecules. Herein, we introduce a high-throughput, data-driven computational framework for the design of novel quantum materials derived from intercalating planar conjugated organic molecules into bilayer transition metal dichalcogenides and dioxides. By combining first-principles methods, material informatics, and machine learning, we characterize the energetic and mechanical stability of this new class of materials and identify the fifty (50) most stable hybrid materials from a vast configurational space comprising ∼105 materials, employing intercalation energy as the screening criterion.
Low-frequency broadband acoustic absorption of a high-order metamaterial with hybrid-damping coupling
Authors: Liu Chongrui , Xie Zexiang , Wu Jiu Hui , Wang Yongquan , Ma Fuyin
Published: November 2024

The causality of passive linear materials dictates both sound absorption performance and structure thickness, making it challenging in the design of thin structures that can approach the causality limits. In contrast to the traditional structure with single damping, a hybrid-damping coupling method is introduced here based on a high-order metamaterial, allowing for superior absorption performance in a thinner structure. In the hybrid-damping high-order cell, the first-order peak is applied with an over-damping impedance to shift the peak toward a lower frequency with the structure thickness unchanged, while the high-order peaks are optimized with matched-damping impedance, avoiding their rapid attenuations in absorption ability. By introducing opposite phases for two first-order peaks, 100% absorption can also be achieved at lower frequencies upon strict coupling. Owing to the near-perfect absorption, the high-order peaks allows for a more sparse arrangement and a lower peak density when coupled, which results in fewer restrictions on peak frequency and greater design flexibility. Therefore, a wider absorption band with superior performance can be achieved in the high-order metamaterial with a fixed number of peaks. By critically coupling 15 high-order cells, a broadband Helmholtz metamaterial is obtained with 95% mean absorption within 210–1860 Hz under a thickness of 135 mm, which is verified by experiments in a square impedance tube. This metamaterial can provide a new way for the low-frequency broadband absorption design and show great potential in noise control engineering applications.
Cryogenic optical-to-microwave conversion using Si photonic integrated circuit Ge photodiodes
Authors: Julien-Neitzert D. , Leung Edward K. , Islam N. , Khorev S. , Shekhar S. , Chrostowski L. , Young Jeff F. , Salfi J.
Published: November 2024

Integrated circuit technology enables the scaling of circuit complexity and functionality while maintaining manufacturability and reliability. Integration is expected to play an important role in quantum information technologies, including in the highly demanding task of producing the classical signals to control and measure quantum circuits at scales needed for fault-tolerant quantum computation. Here, we experimentally characterize the cryogenic performance of a miniaturized photonic integrated circuit fabricated by a commercial foundry that downconverts classical optical signals into microwave signals. The circuit consists of waveguide-integrated germanium PIN photodiodes packaged using a scalable photonic wire bonding approach to a multi-channel optical fiber array that provides the optical excitation. We find the peak optical-to-microwave conversion response to be ∼150 ± 13 mA/W in the O-band at 4.2 K, well below the temperature the circuit was designed for and tested at in the past, for two different diode designs. The second diode design operates to over 6 GHz of 3 dB bandwidth, making it suitable for controlling quantum circuits, with improvements in bandwidth and response expected from improved packaging. The demonstrated miniaturization and integration offers new perspectives for wavelength-division multiplexed control of microwave quantum circuits and scalable processors using light delivered by optical fiber arrays.
High-pressure characterization of Ag3AuTe2: Implications for strain-induced band tuning
Authors: Won Juyeon , Zhang Rong , Peng Cheng , Kumar Ravhi , Gebre Mebatsion S. , Popov Dmitry , Hemley Russell J. , Bradlyn Barry , Devereaux Thomas P. , Shoemaker Daniel P.
Published: November 2024

Recent band structure calculations have suggested the potential for band tuning in the chiral semiconductor Ag3AuTe2 to zero upon application of negative strain. In this study, we report on the synthesis of polycrystalline Ag3AuTe2 and investigate its transport and optical properties and mechanical compressibility. Transport measurements reveal the semiconducting behavior of Ag3AuTe2 with high resistivity and an activation energy Ea of 0.2 eV. The optical bandgap determined by diffuse reflectance measurements is about three times wider than the experimental Ea. Despite the difference, both experimental gaps fall within the range of predicted bandgaps by our first-principles density functional theory (DFT) calculations employing the Perdew–Burke–Ernzerhof and modified Becke–Johnson methods. Furthermore, our DFT simulations predict a progressive narrowing of the bandgap under compressive strain, with a full closure expected at a strain of −4% relative to the lattice parameter. To evaluate the feasibility of gap tunability at such substantial strain, the high-pressure behavior of Ag3AuTe2 was investigated by in situ high-pressure x-ray diffraction up to 47 GPa. Mechanical compression beyond 4% resulted in a pressure-induced structural transformation, indicating the possibility of substantial gap modulation under extreme compression conditions.
In silico design and prediction of metastable quaternary phases in Cu–Ni–Si–Cr alloys
Authors: Díaz Carral Ángel , Gravelle Simon , Fyta Maria
Published: November 2024

Quaternary phases formed in copper alloys are investigated through a combination of quantum-mechanical and classical computer simulations and active machine learning. Focus is given to nickel, silicon, and chromium impurities in a copper matrix. The analysis of the formation enthalpies of candidate quaternary structures leads to the prediction of two novel quaternary phases and the assessment of their stability. For the predicted two phases, machine learned atomistic potentials are developed using active learning with quantum-mechanical accuracy. The use of these potentials in atomistic simulations further elucidates the structure, temperature-dependent dynamics, and elastic behavior of the predicted quaternary phases in copper alloys. The combined in silico approach is thus proven highly efficient in both designing materials and elucidating their properties and potential combining different spatiotemporal scales. In the case of alloys, this computational scheme significantly reduces the effort in searching the huge chemical space of possible phases, enhancing the efficiency in synthesizing novel alloys with pre-defined properties.
Continuous-wave two-photon terahertz quantum cascade laser
Authors: Khabibullin R. A. , Ushakov D. V. , Afonenko A. A. , Pavlov A. Yu. , Galiev R. R. , Ponomarev D. S. , Vasilyev A. P. , Kuzmenkov A. G. , Maleev N. A. , Zubov F. I. , Maksimov M. V. , Belov D. A. , Ikonnikov A. V. , Kuritsyn D. I. , Zhukavin R. Kh. , Kovalevsky K. A. , Anfertev V. A. , Vaks V. L. , Antonov A. V. , Dubinov A. A. , Morozov S. V. , Gavrilenko V. I.
Published: November 2024

We report on the implementation of a terahertz two-photon quantum cascade laser operating in a continuous wave mode. Lasers that can emit two photons as a result of the relaxation of a single electron between two states of the same parity have been discussed since the early days of the laser era, but implementation has been hampered by the lack of a suitable gain medium. The semiconductor structure of a quantum cascade laser seems to be an ideal medium for realizing such two-photon emission. Our work demonstrates dual-band laser radiation in the range of 3.1–3.9 THz (104–130 cm−1) at temperatures up to 90 K.
Magnetic field influence on electron transport in planned GEM-based radiated power diagnostic for DEMO
Authors: Jagielski Michał , Chernyshova Maryna , Malinowski Karol , Quercia Antonio , Fornal Tomasz
Published: November 2024

This work relates to development of diagnostics for radiation power (Prad) and soft x-ray (SXR) intensity measurements in DEMO. A modular, multi-chamber, multi-channel SXR detection system based on gas electron multiplier technology in lateral configuration is currently in conceptual design phase. The high magnetic fields expected at the planned detector positions in the diagnostic ports of the tokamak must be considered in the design. The present study examines two contributions of its influence. The first one pertained to the electric field drifts of thermalized electrons. These were found to be significant, but mostly linear and mitigatable. The second contribution pertained to the impact of magnetic fields on the initial photoelectrons. This was particularly effective in the second detector chamber, which had been optimized for higher photon energies. The size and shape of the electron cloud in a working gas mixture created by primary ionizations have been evaluated as a function of x-ray energy, magnetic field strength, and angle. Moreover, a more direct analysis concerning the loss of electrons in the second chamber has been performed. In this context, the magnetic field was found to have a slightly beneficial effect on the operation of the detector, as it limited the range of ionization perpendicular to its direction and decreased the probability of a primary electron leaving the drift region. Potential design changes resulting from these findings were discussed.
Field emission from cylindrical graphene cathodes prepared by chemical vapor deposition and cold rolling
Authors: Hernandez Nathaniel , Piovesan Azambuja Renato , Cahay Marc , Ludwick Jonathan , Back Tyson , Raut Ayush , Marzana Maliha , Kondapalli Vamsi Krishna Reddy , Fang Qichen , Shanov Vesselin
Published: November 2024

We report field emission (FE) properties of cold cathodes made by a scalable chemical vapor deposition synthesis of three-dimensional graphene (3DG) from a cast catalyst followed by cold rolling. This process leads to an increase in mechanical strength and electrical conductivity of the tested material. For a given distance between the tip of the cathode and the anode, it is found that the FE current from the edge of a single sheet of cold-rolled 3DG-based cathode can be increased by over one order of magnitude when rolling the 3DG sheet in the shape of a cylinder with several turns. A FE current in the order of 4.5 mA was measured from a 3 mm diameter cold-rolled 3DG cylinder with six turns at a bias of 2400 V for a separation of 0.5 mm between the tip of the cylindrical cathode and the anode. The FE data of all cold-rolled 3DG-based cathodes are well fitted by the expression proposed by Abbot, Henderson, Forbes, and Popov [Filippov et al., R. Soc. Open Sci. 9, 220748 (2022)], Im=CVmκexp(−B/Vm), where Im is the FE current, Vm is the bias applied between the cathode and anode, and B and C are fitting parameters. It is found that κ=1 and 3/2 for FE from the surface and edge of the cold-rolled based cathodes, respectively.
Energy harvesting from vibration of stay cables using polyvinylidene fluoride materials: Experimental investigations
Authors: Li Shengli , Cai Daqing , Weng Dawei , Ren Duochang , Guo Pan , Cui Can
Published: November 2024

Piezoelectric energy harvesters (PEHs) have garnered significant attention due to their potential to scavenge ambient vibration energy. However, their application to stay cables presents unique challenges. To evaluate the efficacy of PEHs for cable vibration energy harvesting, this paper conducts field tests on the designed cable polyvinylidene fluoride piezoelectric energy harvester (CPPEH) based on laboratory research. The effects of external load resistance, stay cable parameters, mounting position of the polyvinylidene fluoride (PVDF) piezoelectric film, orientation of the piezoelectric devices, polydimethylsiloxane (PDMS) flexible substrate, and stability of the piezoelectric devices on the energy output performance of CPPEH were studied. Results indicate an optimal resistance of 0.24 MΩ for the CPPEH configuration employing four piezoelectric films connected in parallel. The CPPEH exhibited superior energy performance in the in-plane and vertical installation on the stay cable. Optimal energy harvesting efficiency was achieved with a stay cable length of 91.99 m at an inclination angle of 48.879°. The PDMS flexible substrate enhanced the piezoelectric potential of the CPPEH, while the designed CPPEH demonstrated excellent cyclic stability. This innovative approach introduces a sustainable energy solution for solid bridge cable-stayed structures and offers substantial environmental and economic benefits to bridge infrastructure, offering significant engineering and societal value.
A mean-error-based time-step control method for detonation simulation
Authors: Jia Boyue , Xie Mingyun , Zhang Xuke , Zhang Bin
Published: November 2024

To improve the computational efficiency in implicit-explicit (IMEX) algorithms for stiff detonation problems, the Mean Error Time Control (METC) method is proposed. The core of METC is a novel selected full-field error estimation. This method estimates the full-field error by averaging the errors in regions of significant stiffness. An error controller with integral (I) feedback is then used to determine the neighboring time-step ratios to obtain time-steps within the IMEX stability range. This new strategy ensures a larger time-step while maintaining higher simulation accuracy and making the time-step change more smoothly, providing a reasonable approximation of full-field time error. It is been tested on one-dimensional, two-dimensional oblique, and rotating detonation cases. Compared with the fixed Courant–Friedrichs–Lewy number method, the METC method achieves speedup ratios of 1.48–5.60 for all types of detonation problems related to hydrogen fuels, and the speedup ratio is up to 4.67 for hydrocarbon fuels with greater stiffness. The METC method overcomes the inefficiencies caused by too small a time-step in the Proportional–Integral method in multidimensional reaction flows.
Magnetooptical gyrotropic effects in nanosized BiYIG films and diamagnetic YAG substrates
Authors: Sukhorukov Yu. P. , Telegin A. V. , Lobov I. D. , Naumov S. V. , Dubinin S. S. , Merencova K. A. , Artemyev M. S. , Nosov A. P.
Published: November 2024

Magneto-optical gyrotropic Faraday and Kerr effects are studied in the BiY2Fe5O12 films with thicknesses ranging from 16 to 55 nm, in the wavelength range of 295 nm < λ < 830 nm (4.2–1.5 eV), and under magnetic fields of up to 1.2 T. It is shown that films produced by ac magnetron sputtering on the single-crystalline diamagnetic yttrium aluminum garnet substrates Y3Al5O12 (001) exhibit high structural and magneto-optical quality. The Verdet constant for diamagnetic Y3Al5O12 is determined, and the magnitude of the Kerr effect is estimated for the polished substrate. It is shown experimentally that for a substrate with diffusely reflective backside, the Kerr effect is about zero, except in the high-energy region. For all BiY2Fe5O12 films investigated, in the saturating magnetic fields of approximately 0.16–0.2 T, the value of specific Faraday rotation reaches 20 deg/μm (200 000 deg/cm), while the value of the Kerr effect reaches approximately 20 min (5.8 mrad). The critical thickness of the film–substrate interface was estimated, highlighting variations in the Kerr effect spectra associated with a decrease in the Bi content in thin films with the thicknesses of below 27 nm.
Deep convolutional architectures for optimizing multi-element airfoil systems
Authors: Vishnu Kartikey , Chatterjee Devdoot , Goel Anurag , Kumar Rajeev
Published: November 2024

The investigation of aerodynamic properties in multi-element airfoils is historically challenging and impractical for real-time applications. Predicting specific angles to achieve predetermined lift and drag forces has been elusive. Advances in machine learning (ML) and deep learning (DL) offer new possibilities, but their application to multi-wing system (multi-element airfoils) is limited by scarce datasets. This study explores development, design, and comparative analysis of ML and novel DL algorithms to predict the aerodynamic coefficients generated by multi-element airfoils given airfoil shape, angle of orientation of each airfoil, and their velocity, a previously unexplored area. Using datasets generated via ANSYS Fluent, the proposed models predict aerodynamic coefficients based on variables such as velocity, airfoil angle, and images of the airfoil system with high accuracy, achieving a mean squared error of 0.0049. The proposed approach also significantly reduces the computational time for predicting the aerodynamic coefficients from 10 to 15 min in a traditional computational fluid dynamics simulation to 1–6 ms using our approach. This real-time prediction capability allows for assessing various angle combinations to find optimal orientations for specific drag and lift forces.
Enhancing shale gas recovery and CO2 sequestration: Microscopic mechanisms of adsorption and diffusion in shale pores
Authors: Chang Xin , Lin Shuangshuang , Yang Chunhe , Guo Yintong , Dai Xiulan
Published: November 2024

The global energy imbalance has created significant challenges and environmental consequences. Integrating carbon sequestration with shale gas development provides a promising solution to address both issues simultaneously. This study explores the adsorption, desorption, and diffusion behaviors of methane and CO2 in shale pores using a high-precision, high-pressure adsorption apparatus alongside molecular simulation techniques. Results demonstrate that CO2 shows a markedly higher adsorption capacity in shale pores than methane, particularly at high pressures. Simulations reveal that CO2 molecules nearly saturate pore spaces at pressures above 10 MPa. Methane's diffusion coefficient, initially high at low pressures, drops sharply with increasing pressure, decreasing by approximately 90% from 5.6 × 10−10 m2/s at 154 psi to 1.38 × 10−11 m2/s at 1032 psi. Conversely, CO2 diffusion remains stable under pressure changes, suggesting that methane diffusion is constrained by intermolecular interactions at high pressures, while CO2 retains stable movement. Under a reservoir condition of 30 MPa with adsorbed CH4, CO2 injection at varying pressures continues to enhance CO2 adsorption, underscoring CO2's dual role in boosting shale gas recovery while achieving carbon sequestration. This study highlights CO2-methane displacement mechanisms, providing theoretical insight that support both effective shale gas recovery and CO2 storage.
Single parameter aging and density scaling
Authors: Hecksher Tina , Niss Kristine
Published: November 2024

In a recent paper, Di Lisio et al. [J. Chem. Phys. 159, 064505 (2023)] analyzed a series of temperature down-jumps using the single-parameter aging (SPA) ansatz combined with a specific assumption about density scaling in the out-of-equilibrium system and did not find a good prediction for the largest down-jumps. In this paper, we show that SPA in its original form does work for all their data, including large jumps of ΔT > 20 K. Furthermore, we discuss different approaches to the extension of the density scaling concept to out-of-equilibrium systems.
Evolution of secondary vorticity following vortex ring impact on a concave hemicylindrical cavity
Authors: Ahmed T. , Erath B. D.
Published: November 2024

The generation of secondary vortices from a wall-bounded vorticity sheet is a frequent occurrence in vortex ring–structure interactions. Such interactions arise in both engineering and biomedical applications, including tracheoesophageal speech. This study investigated the evolution of secondary vorticity following impact of an axisymmetric vortex ring on a concave hemicylindrical cavity. A primary vortex ring (PVR) with a formation number of F=2.00 and Reynolds number of ReΓ=1500 was generated within a water tank. Five different ratios of hemicylindrical cavity radius (Rcyl) to PVR radius (Rv) were examined; namely, γ=4,  3,  212,  2, and 112. Flow visualization and particle image velocimetry analysis of the scenarios revealed the asymmetric impact of the PVR on the cavity surface. This asymmetric impact leads to distinctive flow dynamics in the evolution of secondary vorticity across both the transverse and longitudinal planes. In the transverse plane, the PVR impact generated a secondary vortex ring (SVR) and a tertiary vortex ring (TVR). Following generation, the SVR and TVR rotated completely around the PVR. In the longitudinal plane, the SVR produced a horseshoe-like loop instead of rotating around the PVR completely. For γ=4,  3, and 212, the SVR loop moved upward due to self-induction. For γ=2 and  112, the legs of the SVR horseshoe-like loop experienced reconnection and produced two new vortex rings. The upward trajectory of the SVR horseshoe-like loop varied with γ, tending to move further from the primary ring's axis as γ decreased.
Distinct topological Hall responses in CeCu2-type EuZn2 and EuCd2 films
Authors: Watanabe Yuto , Nishihaya Shinichi , Kriener Markus , Nakamura Ayano , Uchida Masaki
Published: November 2024

Rare-earth intermetallic compounds crystallized in AlB2-type and its low-symmetry derivative CeCu2-type structures potentially host diverse frustrated magnetic structures and rich magnetotransport phenomena. We report the film growth of CeCu2-type EuZn2 by molecular beam epitaxy and the observation of topological Hall responses highly contrastive to isostructural EuCd2. While their magnetization curves are rather similar, the topological Hall effect observed in EuZn2 is simpler, with the only one component enhanced at the magnetic transition field. EuZn2 may be a unique system for studying the magnetic domain boundary effect on topological Hall responses among the CeCu2-type rare-earth intermetallic compounds.
A vortex-tracking method based on multi-attribute fusion
Authors: Zhu Lin , Guo Ningbo , Wu Yadong , Deng Liang , He Zhouqiao , Chen Cheng , Xing De
Published: November 2024

Tracking time-variant vortex features in unsteady flow fields represents a significant challenge in scientific visualization. In this paper, we propose an innovative new method based on attribute fusion that leverages unsupervised clustering techniques to track time-variant vortex features. This method has the potential for use in large-scale flow field analysis. We apply an attribute matrix integrating the spatial and physical variables of vortex feature points. We then fuse and reduce the dimensionality of this original matrix to create an attribute fusion matrix. Subsequently, we apply coarse clustering to the fusion matrices across time steps. By defining a distribution curve, we derive a similarity measurement matrix among different vortices. Vortex matching is performed based on this similarity measurement to enable the tracking of time-variant vortices. Multiple experimental datasets demonstrate the effectiveness and matching efficiency of the proposed method.
Transmission of mobility via cooperative mechanisms in soft active matter
Authors: Teboul Victor
Published: November 2024

When supercooled, liquid's viscosity increases dramatically as the glass transition temperature is approached. Although the physical origin of this behavior is still not understood, it is now well established that the addition of a few activated particles is able to reverse that increase in viscosity. Here we further raise the question of a limit in that fluidization process and of the differences between the fluidized liquid and its viscous counterpart. The results show that a few percent active molecules are enough to trigger a phase transition leading to diffusion coefficients typical of liquids while the medium retains cooperative properties of the viscous phase. The similarity between cooperative properties of the active and non-active molecules suggests that the mobility of active molecules is transmitted to inactive ones via the medium's cooperative mechanisms, a result in agreement with facilitation theories. This result is then confirmed by the compared behavior of the distinct Van Hove correlation functions of most mobile active and non-active molecules. Interestingly enough, in our simulations, the cooperative mechanisms are not induced or related to a decrease in the excitation concentration.
Tunable terahertz intrinsic chiroptical absorption empowered by accidental bound states in the continuum
Authors: Zhang Rui , Li Xiao-Chun , Liu Qing Huo
Published: November 2024

Terahertz (THz) bound states in the continuum (BICs) present a significant opportunity to achieve ultra-high quality (Q) factors in chiroptical responses, which are essential for high-resolution spin-selective devices. However, most high-Q chiroptical resonances rely on symmetry-protected BICs, attained either via electromagnetic oblique incidence or structural anisotropy to obtain extrinsic chirality (false chirality). Recently, the intrinsic chirality (true chirality) has been achieved through the breaking of both in-plane (C2) and out-of-plane (σz) symmetries. In this Letter, we utilize two accidental BICs to demonstrate dual-frequency intrinsic chirality without breaking σz symmetry. By carefully tuning structural parameters, we can manipulate the circularly polarized states (C points) located at the Γ-point in k-space, leading to the achievement of intrinsic chiral quasi-BICs. Under left/right circularly polarized wave illumination, the maximum optical absorption is 99.56%/5.69% at 0.4469 THz and 3.37%/98.78% at 0.4584 THz, with circular dichroism (CD) maxima of 0.939 and −0.954, and Q-factors of 2917 and 1433, respectively. The dual-frequency intrinsic chirality can be dynamically controlled through changing the Fermi level EF of the graphene substrate. The CD peak values for quasi-BIC 2 and quasi-BIC 3 can be continuously tuned within the ranges of 0.059–0.792 and −0.218 to −0.889, respectively, as EF increases from 0.05 to 1.00 eV. Our work provides a unique design path for achieving optical intrinsic chirality, with potential applications in THz biomedical detection, radar stealth, and other spin-selective devices.
The limits of mathematics in physics
Authors: Kalies Grit , Do Duong D.
Published: November 2024

Mathematics is considered the language of physics. Starting from idealizations and kinematics, geometric-mathematical physics with paradigms such as flexible spacetime and dark energy has emerged whose physical reality has not been clarified. By analyzing processes regarding their causes and the functional dependencies of energies, this work identifies shortcomings in the basic energy concepts of physics, which cannot be remedied with mathematics. While formal transformations of process equations such as integration are mathematically correct, they do conceal vital physical information, suggesting that mathematics should be used with caution. We propose a physically justified approach that reconciles the mechanical and thermodynamic energy concepts and provides a revised interpretation of E = mc2. Our results suggest that geometric approaches were built too early on a shaky physical foundation, leading to undesirable developments in recent centuries. The language of physics should be physics, not just mathematics.
PbZrO3-based thin film capacitors with high energy storage efficiency
Authors: Son Yeongwoo , Udovenko Stanislav , Gaur Anand P. S. , Cui Jun , Tan Xiaoli , Trolier-McKinstry Susan
Published: November 2024

Antiferroelectric (Pb0.87Sr0.05Ba0.05La0.02)(Zr0.52Sn0.40Ti0.08)O3 thin film capacitors were fabricated for dielectric energy storage. Thin films with excellent crystal quality (FWHM 0.021°) were prepared on (100) SrRuO3/SrTiO3 substrates by pulsed laser deposition. The out-of-plane lattice constant of the thin film was 4.110 ± 0.001 Å. An average maximum recoverable energy storage density, 88 ± 17 J cm−3 with an efficiency of 85% ± 6% at 1 kHz and 80 ± 15 J cm−3 with an efficiency of 91% ± 4% at 10 kHz, was achieved at room temperature. The capacitor was fatigue resistant up to 106 cycles at an applied electric field of 2 MV cm−1. These properties are linked to a low level of hysteresis and slow polarization saturation. PbZrO3-derived oxide thin film capacitors are promising for high efficiency and low loss dielectric energy storage applications.
Gradient-guided Convolutional AutoEncoder for predicting CO2 storage in saline aquifers with multiple geological scenarios and well placements
Authors: Hu Zongwen , Wang Jian , Yan Xia , Yao Jun , Sun Hai , Yang Yongfei , Zhang Lei , Zhong Junjie
Published: November 2024

CO2 sequestration in saline aquifers is a crucial component of carbon capture, storage, and utilization (CCUS) technology. The subsurface fluid flow of CO2 and brine in porous media involves the coupling of multiple physics fields, featuring complex nonlinear partial differential equations (PDEs). The prevalent approach for studying subsurface fluid flow is to discretize PDEs in spatial and temporal dimensions and solve them numerically. Here, this work proposed a Gradient-guided Convolutional AutoEncoder (GCAE), where the gradient differential operator is incorporated as physical prior knowledge into the loss function of the neural network. The physical prior knowledge guides the training process of the neural networks, enhancing their physical interpretability compared with the purely data-driven Convolutional AutoEncoder (CAE). This work applied GCAE to the CO2 sequestration in the homogeneous formation, the heterogeneous formation, as well as the heterogeneous formation with different well placements to demonstrate the improvement in prediction accuracy, data stability, and generalization capability compared with the CAE approach.
Impact response of pseudoelastic nitinol
Authors: Zaretsky E. B. , Paris V. , Efremenkov I. , Kalabukhov S. , Hayun S.
Published: November 2024

The response of polycrystalline nitinol with solely austenite structure was studied in three series of planar impact tests characterized by loading of the nitinol samples of 0.5–10 mm thickness by 1 mm thick aluminum impactor accelerated up to velocities of about 387, 429, and 567 m/s. In all the tests, the velocities of the free surfaces of the samples were monitored by a laser velocity interferometer. It was found that in all three test series, the amplitude of elastic precursor wave, being initially greater than 4 GPa, rapidly decays with the propagation distance down to ∼2.5 GPa, below which the decay is hindered by atomic clusters of the nanometer size. Based on the part of the velocity histories indicating the shock-induced austenite–martensite transformation, the initial, of about 2.5 × 103 s−1, and the maximum, up to 1 × 105 s−1, rates of the transformation were determined. As well, the impact stress slightly greater than 4 GPa was determined as that required for the onset of the B2 → B19′ transformation under shock loading. The unloading parts of the same velocity histories allowed a rough estimate of the fraction of the shock-transformed martensite and the elucidation of the virtually complete reversibility of the transformation.