bluuebunny/crossref_metadata_2025 huggingface dataset:
Wave propagation along the interface between the hyperbolic graded-index and photorefractive crystals
Authors: Savotchenko S.E.
Published: November 2024

New two types of transverse interface waves propagating along the planar contact the photorefractive and hyperbolic graded-index crystals are described theoretically. The waves are given by exact analytical solutions to the stationary wave equations with spatial dependent coefficients. The waves of the two types differ from each other by the presence of oscillations of the decaying field profile in the photorefractive crystal and the range of existence. Influence on the wave profiles of the system parameters such as the effective refractive index, temperature, and the hyperbolic profile parameters (the interface refractive index, and the characteristic distance) are analyzed in details. New features of the distribution of the maxima and minima of the field profile and the depth of its penetration into crystals depending on the values of these parameters are specified.
Développement d’une Grille d’Observation des habiletés individuelles reliées au Travail d’équipe lors d’une RÉAnimation Traumatologique (GO-TREAT) en contexte de simulation clinique
Authors: Lapierre Alexandra , Arbour Caroline , Lavoie Patrick
Published: November 2024

Contexte : Il n’existe aucune grille d’observation pour documenter les habiletés individuelles de travail d’équipe qui sont mobilisées lors d’une réanimation traumatologique. But : Présenter les premières étapes du développement de la Grille d’Observation des habiletés individuelles reliées au Travail d’équipe lors d’une RÉAnimation Traumatologique (GO-TREAT) en contexte de simulation clinique et proposer une version préliminaire. Méthode : Cette démarche s’est initialement appuyée sur des recommandations reconnues pour traduire, adapter et réaliser la validation transculturelle d’un outil d’évaluation, l’Observational Skill-based Clinical Assessment tool for Resuscitation (OSCAR). Une première phase de traduction et d’adaptation de l’OSCAR a été effectuée auprès de deux traducteurs. Neuf experts en traumatologie à la salle d’urgence ont validé le contenu des énoncés de la grille. À la suite de ces étapes, plusieurs modifications ont été apportées par l’équipe de recherche menant au développement d’une toute nouvelle grille intitulée : GO-TREAT. Une mise à l’essai préliminaire a été effectuée à l’aide de 16 enregistrements vidéo de simulations interprofessionnelles en traumatologie. Résultats : Une version préliminaire de la GO-TREAT est présentée et propose des énoncés reliés à cinq sous-domaines du travail d’équipe (communication, coopération, coordination, leadership, surveillance) chez six professionnels composant l’équipe en traumatologie : inhalothérapeute, infirmier-ère au patient et médicaments, infirmier-ère aux notes, infirmier-ère leader, médecin leader, second médecin. Lors de la mise à l’essai, un effet plafond a été observé pour la moitié des énoncés de la grille. Conclusion : Des recommandations ont été émises pour le raffinement et l’évaluation plus approfondie de la GO-TREAT.
Artificial intelligence in planned orthopaedic care
Authors: Georgiakakis Elena Chiara Thalia , Khan Akib Majed , Logishetty Kartik , Sarraf Khaled Maher
Published: November 2024

The integration of artificial intelligence (AI) into orthopaedic care has gained considerable interest in recent years, evidenced by the growing body of literature boasting wide-ranging applications across the perioperative setting. This includes automated diagnostic imaging, clinical decision-making tools, optimisation of implant design, robotic surgery, and remote patient monitoring. Collectively, these advances propose to enhance patient care and improve system efficiency. Musculoskeletal pathologies represent the most significant contributor to global disability, with roughly 1.71 billion people afflicted, leading to an increasing volume of patients awaiting planned orthopaedic surgeries. This has exerted a considerable strain on healthcare systems globally, compounded by both the COVID-19 pandemic and the effects of an ageing population. Subsequently, patients face prolonged waiting times for surgery, with further deterioration and potentially poorer outcomes as a result. Furthermore, incorporating AI technologies into clinical practice could provide a means of addressing current and future service demands. This review aims to present a clear overview of AI applications across preoperative, intraoperative, and postoperative stages to elucidate its potential to transform planned orthopaedic care.
SUPRAORBITAL AND ENDONASAL APPROACHES: TAILORING SURGICAL TECHNIQUES FOR TUBERCULUM SELLAE MENINGIOMAS BASED ON PREOPERATIVE GRADING SYSTEMS
Authors: Ricciuti Riccardo Antonio , Mancini Fabrizio , Paracino Riccardo , Ottaviani Matteo Maria , De Domenico Pierfrancesco , Barbieri Francesca Romana , Marruzzo Daniele , Pagano Serena , Vecchioni Stefano , Conti Carlo
Published: November 2024

Background
Tuberculum sellae meningiomas (TSM) tend to compress the optic apparatus and an ideal surgical route, whether transcranial or endonasal, is still debated. Another issue is if the minimally invasive supraorbital (SO) approach offers the same results compared to the more invasive craniotomy. Aiming to guide approach selection, preoperative grading systems have been described.

Method
All cases of TSM treated from 2013 to 2018 by extended endoscopic endonasal (EEA) or SO approach have been reviewed and classified according to three preoperative grading system: McDermott scale, Optic Nerve Laterality Score and Yaşargil criteria.

Results
A total of 15 patients with TSM were treated with the EEA (n=6) or the SO (n=9) approach. Globally, gross total resection was obtained in 87% (n=13) of cases and was higher with the SO (100%, n=9) compared to the EEA (67%, n=4). Visual function improved in all but one patient (n=14). Compared to the EEA group, patients treated by the SO approach had larger tumors (32.3 mm vs 24.5 mm), higher rate of optic canal invasion (4/9 vs 0/6) and arterial encasement (6/9 vs 1/5). Patients with McDermott total point of 1-2 (7/15) were treated mainly by the EEA; all patients with McDermott total score ≥3 (8/15) were treated by the SO approach. All patients with optic canal invasion (4/15) and lateral extension of the tumor (ONL score = 1-3) were treated by the SO approach.

Conclusions
The SO and EEA are two minimally invasive approaches safe and effective for treating TSM. For tumors with lateral extension (optic nerve laterality score = 1-3), larger diameter (> 30-35 mm), vascular encasement or optic canal involvement (McDermott total point = 2-3), the SO craniotomy is preferred. For small and median tumors with no optic canal invasion or vascular encasement (McDermott total point = 1-2), the EEA represents a valid option.
Clinical outcomes of revision posterior lumbar interbody fusion for late deterioration after laminotomy assessed with the Zurich Claudication Questionnaire
Authors: Sakaura Hironobu , Fujimori Takahito , Sugiura Tsuyoshi , Yamada Shutaro , Kanayama Sadaaki , Ikegami Daisuke
Published: November 2024

Study Design: A retrospective analysis of prospectively collected data.
Background: There have been a few studies comparing surgical outcomes between revision lumbar fusion surgery and the same primary surgery.
Object: Using the Zurich Claudication Questionnaire (ZCQ), we compared clinical outcomes of revision posterior lumbar interbody fusion (PLIF) for late deterioration after laminotomy with those of primary PLIF to examine whether surgical outcomes of revision PLIF for late deterioration after laminotomy are inferior to those of primary PLIF.
Materials and Methods: Sixteen consecutive patients undergoing revision single-level PLIF for late deterioration after single-level laminotomy (R group) and 61 consecutive patients undergoing primary single-level PLIF during the same period as the R group (P group) were enrolled. Before PLIF surgery and at 2-year postoperatively, clinical outcomes were assessed using the ZCQ. Achievement rates of the minimum clinically important difference (MCID) of each domain [Symptom severity (SS) and Physical function (PF)] on the ZCQ were calculated in each group.
Results: In the R group, mean SS and PF before revision PLIF and at 2-year after surgery were 3.429 and 2.8, and 1.946 and 1.6, respectively. In the P group, mean SS and PF before primary PLIF and at postoperative 2-year were 3.438 and 2.5, and 2.194 and 1.6, respectively. Both SS and PF significantly improved at postoperative 2-year in the both groups, and SS both before and after PLIF and PF at 2-year postoperatively showed no significant differences between the 2 groups. Achievement rates of the MCID of SS and PF were 81.3% and 68.8% in the R group, and 59.0% and 59.0% in the P group, respectively. None of the MCID achievement rates of SS and PF showed significant differences between the 2 groups.
Conclusion: Clinical outcomes of revision PLIF for late deterioration after laminotomy were equivalent to those of primary PLIF assessed with the ZCQ at 2 years after PLIF surgery.
Otogenic brain abscess and concomitant acute COVID 19 infection – case report and review of the literature
Authors: Rafaelian Artem , Won Sae-Yeon , Trnovec Svorad , Behmanesh Bedjan , Barz Susanne , Busjahn Christoph , Reuter Daniel A. , Zhang Lichun , Mlynski Robert , Freiman Thomas , Gessler F , Dubinski Daniel
Published: November 2024

Abstract
Background: COVID-19 has attracted global attention primarily because of the severe acute respiratory symptoms associated with it. However, nearly one third of the patients also present with neurologic symptoms. This report describes a case of a previously healthy woman with acute COVID-19 infection, who developed acute facial nerve palsy and rapid progression to coma due to otogenic brain abscess.

Case Description: A 63-year-old woman with acute COVID-19 infection exhibited acute facial nerve paresis, high fever and purulent secretion from her left ear within 48 hours after COVID-19 onset. Cranial CT scan confirmed acute mastoiditis, precipitating an urgent mastoidectomy. A postoperative contrast-enhanced MRI on the same day revealed a subdural empyema, which prompted an urgent craniotomy and decompression. Intraoperative microbiological swabs confirmed a Streptococcus pyogenes infection, however RT-PCR was negative for SARS-CoV-2. After immediate i.v. antibiotic treatment, extubation was achieved four days post-operation, and the patient was discharged without neurologic deficits 19 days after postoperatively.
Conclusion: This finding adds a layer of insight into the specific nature of the infection, suggesting a potential absence of SARS-CoV-2 involvement in otogenic subdural empyema. However, the impact of SARS-CoV-2 in otogenic brain abscess cannot be excluded to date and should be further prospectively investigated. The complete recovery of neurological status, emphasizes the importance of prompt and interdisciplinary interventions in managing rare and severe complications associated with COVID-19.
Keywords: Coronavirus disease 2019, facial nerve paresis, encephalitis, mastoiditis, subdural empyema
Management of subarachnoid-pleural fistula following anterior transthoracic approach for the ossification of posterior longitudinal ligament in the thoracic spine
Authors: Kanematsu Ryo , Hanakita Junya , Minami Manabu , Takahashi Toshiyuki
Published: November 2024

Background: Subarachnoid–pleural fistula is an abnormal communication between the subarachnoid and pleural spaces that can arise from blunt or penetrating trauma or as a complication of spinal surgery via the transthoracic approach. Uncontrolled cerebrospinal fluid (CSF) leakage with a fistulous condition after transthoracic spinal surgery could be more problematic than that after spinal surgery via the conventional posterior approach because of the negative pressure in the pleural cavity.
Case description: The authors reported subarachnoid–pleural fistula management using chest and lumbar spinal drainage in five patients with several troublesome complications, such as intracranial subdural hematoma or severe respiratory dysfunction. Chest drainage was managed for 2–3 days by continuous low negative pressure, whereas lumbar spinal drainage was managed for 5–7 days, aiming at an output volume of 150–200 ml/day and higher than that of chest drainage. Additionally, when examining changes in the accumulated pleural fluid were examined by standing chest X-ray immediately before operation and 1 month after operation, the pleural effusions in four of the five patients were assimilated 1 month postoperatively.
Conclusion: Compared with CSF management following standard posterior spinal surgery, management after the anterior transthoracic approach could be more troublesome because of intrapleural negative pressure. When chest and lumbar spinal drainage are used, it is important to consider that over-drainage of CSF could potentially cause severe respiratory dysfunction and intracranial subdural hematoma.
Parallel pumping in a two-dimensional electron plasma at the liquid helium surface
Authors: Govorkov S. A. , Tulin V. A.
Published: November 2024

We investigate the radio-frequency absorption in a capacitor containing electrons at the liquid helium surface. The absorption at a constant surface electron concentration is shown to be inversely proportional to the surface electron concentration.
High frequency conductivity of granular media
Authors: Shekhter R. I.
Published: November 2024

A theory of non steady-state conductivity in granular media is formulated. The frequency dispersion and temperature dependence of high frequency conductivity caused by charge carrier quantization are studied.
Current-controlled superconductive bridge contacts
Authors: Kulik I. O. , Omel’yanchuk A. N. , Kel’man É. A.
Published: November 2024

A theory is offered for weakly coupled superconductive structures in which the critical bridge (film) current is varried by passing a current perpendicular to the transport current through a weak spot. Various types of such current-controlled contacts are considered (film–film, film–bridge, bridge–bridge). Josephson multiports are considered as a general case and boundary conditions are obtained for the order parameter in the weak intersection region. An expression is obtained for maximum superconductive current in the transport circuit as a function of control current. It is established that the effect of change in the maximum transport current appears at control currents close to critical, and in the resistive state of the control circuit.
Raman sound scattering in normal metals and superconductors
Authors: Geǐlikman B. T. , Reǐzer M. Yu.
Published: November 2024

Raman sound scattering (RSS) is considered in normal metals and in superconductors. The scattering amplitude, calculated by second order perturbation theory from the Fröhlich Hamiltonian, has a resonance nature, enabling the observation of RSS at low temperatures in pure samples. High-frequency sound is considered in the two regions: A – ω ⪡ T and B – ω ⪢
The Shubnikov–de Haas effect in Sb1–xBix alloys (0 ≤ x ≤ 0.25)
Authors: Gitsu D. V. , Muntyanu F. M. , Onu M. I.
Published: November 2024

The Shubnikov–de Haas effect was studied in Sb1–xBix alloys (0 ≤ x ≤ 0.25) in stationary magnetic fields of up to 175 kOe. The cyclotron mass, Fermi energy, Dingle temperature, and carrier concentration are estimated. The cross-sectional areas of the Fermi surfaces of electrons and holes were observed to vary linearly with an increase in the bismuth concentration in the alloys.
Temperature dependence of antiferromagnetic resonance in the spin-flop phase
Authors: Galkin A. A. , Danyshin N. K. , Vetchinov A. V.
Published: November 2024

The temperature dependence of antiferromagnetic resonance in CuCl2⋅2H2O in the spin-flop phase is investigated at a number of discrete frequencies ranging from 9 to 37 GHz in the temperature range 1.65–4.2°K in fields of up to 14 kOe. The data obtained are compared with theory.
Critical temperature of low-dimensionality Heisenberg ferromagnets
Authors: Slyusarev V. A. , Yankelevich R. P.
Published: November 2024

Multilayer Heisenberg ferromagnets and two-dimensional magnetic structures with single-ion anisotropy are analyzed by the renormalization group method. The results describe the dependence of the critical temperature on the values of the exchange integrals and on the anisotropy constant.
Diamagnetic resonance in Pb1–xSnxTe
Authors: Bratashevskii Yu. A. , Prozorovskii V. D. , Khaionovskii Yu. S.
Published: November 2024

Diamagnetic resonance on a group of electrons with an anomalously weak anisotropy of effective mass (∼10–3m0) in specimens of n-Pb1–xSnx Te single crystals rich in tellurium vacancies was studied over the 1.6–3°K temperature range. There have been established a strong temperature dependence, with a negative temperature coefficient, and a commutation of the cyclotron line upon reversal of the magnetic field, the latter indicating a ferromagnetic ordering of the system and attributed to the presence of tellurium vacancies participating in indirect exchange with conduction electrons.
The effective temperature in fluctuation detachment of dislocations from pinning centers
Authors: Roshchupkin A. M. , Miloshenko V. E.
Published: November 2024

The effective temperature T* which takes into account quantum effects when dislocations are detached by fluctuations from local centers is determined by the mean energy per vibrational degree of freedom. The Debye approximation is used to derive an analytical temperature dependence for T*.
Quantum diffusion of He3 in solid He4. I. The role of impurity interaction anisotropy
Authors: Slyusarev V. A. , Strzhemechnyi M. A. , Burakhovich I. A.
Published: November 2024

We propose a semiquantitative theory of He3 diffusion in solid He4 in the impuriton region. We calculate the impurity interaction potential for cubic and hcp crystals, and estimate the potential amplitude in the bcc and hcp crystals of solid He4. The differential scattering cross section is calculated in the eikonal approximation for a strongly anisotropic potential. The results are used to calculate, by means of kinetic equations, the diffusion coefficient of the mutually scattered impuritons. Using the available experimental data we estimate the impuriton band-width to be about 2·10–5°K.
Thermal expansion of solid CD4
Authors: Tolkachev A. M. , Aleksandrovskii A. N. , Manzhelii V. G.
Published: November 2024

A study has been made of the thermal expansion of solid deuteromethane over the range 2–17 °K there is a singularity in the expansion due to traces of CHD3. The expansion coefficient of pure solid deuteromethane has been determined.
Coexistence of free and self-localized excitons in solid argon
Authors: Fugol' I. Ya. , Savchenko E. V. , Grigorashchenko O. N.
Published: November 2024

New experimental features of the intrinsic luminescence of crystalline argone are reported; the free- exciton luminescence has been measured near the edge of the Λ (3/2), n = 1 intrinsic absorption band. On the basis of the data obtained the possibility for coexistence of free and self-localized excitons is discussed. It is found that the free excitons can coexist with self-localized ones of various types (two-center and one-center).
Study on the correction of the influence of thin film in the calibration of high-frequency hydrophone by laser Doppler vibration measurement
Authors: Yi Chang , Zhang Hengda , Zheng Huifeng , Gao Chu , Gao Shenping , Wang Xiaobo , Wu Delin , Wang Hongyuan , Yao Lei
Published: November 2024

In the process of using laser interference calibration method to calibrate high-frequency hydrophones, a transparent reflective film will be used. This article studies the influence of the film on the calibration results. The theoretical calculation formula for the sound pressure transmission coefficient of thin films was derived through the impedance transfer method of multi-layer media. It can be observed that the sound pressure transmission coefficient decreases with increasing frequency, which means that the higher the frequency, the greater the influence of the thin film. When the ultrasonic frequency reaches 10 MHz, the sound pressure transmission coefficient of the thin film with a thickness of 15 μm decreases to 0.9017. The sound pressure measured by the laser Doppler vibrometer method was corrected by the sound pressure transmission coefficient and compared with the results measured by a standard hydrophone. Experiments were conducted to measure the sound pressure at frequencies of 1, 2, 3, 5, and 10 MHz. The results showed that correcting the measurement results of the laser vibrometer method by the sound pressure transmission coefficient can effectively reduce measurement errors.
Experimental and numerical analysis on the cutting force, cutting temperature, and tool wear of alloy steel (4340) during turning process
Authors: Veerappan G. , Logesh Kamaraj , Chaturvedi Rishabh , Ravichandran Manickam , Mohanavel Vinayagam , Hossain Ismail , Kannan Sathish , Alotaibi Majed A. , Seikh Asiful H.
Published: November 2024

This paper focuses primarily on the wear behavior observed in AISI4340 steel when machining with a multi-layered coated carbide tool. Numerical and experimental examination is processed out to predict the wear performance of AISI 4340 steel along with its cutting force and temperature. In this process, four layers of different coated material are bonded together to form a multi-layered coated carbide tool. The coated thickness is assessed with the assistance of a Scanning Electron Microscope (SEM). Experimental analysis takes place with a heavy duty lathe machine equipped with an infrared thermometer and force dynamometer. Simulation is performed using DEFORM-2D software to simulate cutting forces and interface temperature, and the output results obtained have been compared with the experimental work. With the help of the SEM image, maximum crater wear depth is evaluated and analyzed. Feed plays a crucial role in increasing the chip interface temperature and cutting force. For varied feed rates, the cutting tool edge radius, depth of cut, and cutting speed are taken as the input parameters. The proposed 2D finite element model provides effective parameter values for reducing wear. Results measured indicate that the output parameter values of interface temperature and cutting force obtained from simulation and experimental investigation match each other with high accuracy. Simulation results for temperature distribution around the tool tip show that a maximum temperature of 654 °C is formed at the feed rate of 0.4 mm/rev, leading to high heat flux. For the feed rate of 0.3 and 0.2 mm/rev, there is not much deviation in heat flux around the tool tip. The maximum temperature around the tool tip is near 527 °C for both 0.3 and 0.2 mm/rev. Simulation results show that the lowest tool wear of 0.001 23 mm was obtained for a feed rate of 0.2 mm/rev, followed by 0.004 25 (0.1 mm/rev), 0.005 09 mm (0.4 mm/rev), and 0.007 14 mm/rev.
Analysis of the decay process of the radiation dose rate using open data on the Internet
Authors: Nishiwaki Yoichi , Takashige Masaaki
Published: November 2024

We report on an example of teaching material for analyzing the decay process of the radiation dose rate without using actual radioactive materials. Radiation dose rate data related to the 2011 Fukushima nuclear power plant accident has been obtained from monitoring posts across Japan and is publicly available on the Internet. Changes in radiation dose rates over 10 years can be analyzed using the least squares method on theoretical curves using Microsoft Excel. We explore the educational potential of this open data as a tool for instructors who teach physics experiments as part of introductory education in university science and engineering departments. This teaching material using open data is a much less time-consuming and inexpensive way to learn about the decay process of the radiation dose rate while ensuring safety. The analysis results could provide students with a wide range of topics for discussion that include the connection between data and real-world problems, and between environmental and energy issues.
Array hollow-anode microsecond-pulsed plasma jets at atmospheric pressure: mode transition and influencing factors
Authors: Chen Bohan , Liu Zhijie , Zhang Mingyan , Zhang Zekai , Guo Hezhi , Li Xin , Pang Bolun , Gao Yuting
Published: November 2024

Hollow cathode plasma jets are commonly utilized across various fields, yet there is limited research on hollow anode discharge, particularly on array hollow anode plasma jets. This letter presents the novel design of a array hollow anode discharge device excited by microsecond pulse. Systematical investigations about the discharge characteristics and mode transition process of the device are examined from the perspectives of electricity and space-time distribution to get insights into the formation mechanisms of array hollow anode plasma jets. Results show that three distinct discharge modes when the array hollow anode plasma jets interacting with ITO plate are identified based on the number and location of the discharged hollow anodes: Mode A involves all 16 hollow anodes discharging, Mode B entails 12 hollow anodes discharging, and Mode C comprises 4 hollow anodes discharging at the four vertices of the device. It is observed that experimental outcomes are influenced by the distance from the hollow anode tube port to the plate. The formation mechanism is determined by an increase in distance impacting spatial electric field distribution and facilitating mode transition. Furthermore, the impacts of pulse voltage, pulse frequency, and flow rate on the variation of interval length under different modes are investigated. The results indicate that voltage has the most significant effect on interval length, followed by frequency, while flow rate has a minimal effect. These findings hold significant implications for enhancing understanding of mode transition and influencing factors of array hollow anode plasma jets.
3D-simulation design of a high current capacity GaN tri-gate power device with integrated parasitic bipolar junction
Authors: Song Chuan , Yang Wen , Jiang Huaxing , Li Bin
Published: November 2024

In this work, a novel high current capability gallium nitride (GaN) tri-gate power device with an integrated parasitic bipolar junction transistor (BJT) is proposed to enhance its static electrical characteristics. The device’s electrical characteristics are thoroughly studied and analyzed using 3D technology computer-aided design simulation tools. The two-dimensional electron gas channel is effectively pinched off in the off-state due to the depletion region induced by side-gate metals and parasitic BJT, resulting in a positive threshold voltage (V
TH) and enhanced mode (E-mode) operation. The parasitic BJT provides an additional conductive channel in the on-state, significantly improving the output current capability. Compared with the conventional tri-gate (C-Trigate) device, the proposed high current capability GaN trigate (HC-Trigate) device boosts saturation output current by nearly a factor of three under identical conditions, reaching 1,761 mA mm−1. The 3D simulation shows the proposed GaN HC-Trigate power device features a positive V
TH of 1.1 V, a low specific on-resistance (R
on,sp) of 0.18 mΩ*cm2 at breakdown voltage of 760 V, and the Baliga’s figure of merit of 3.21 GW cm−2. Furthermore, the GaN HC-Trigate power device exhibits superior thermal performance and switching characteristics, indicating its great potential for power electronics applications.
Wave propagation in functionally graded piezoelectric sandwich nanoplates based on nonlocal strain gradient theory incorporating surface effects
Authors: Wang Jie , Liu Juan , Hu Biao , Zhang Bo , Wang Xinte , Wang Yuxing , Wang Jing
Published: November 2024

In this study, wave propagation characteristics in functionally graded (FG) piezoelectric sandwich nanoplates under electro-thermal loading are investigated. The sandwich nanoplates comprise piezoelectric layers, with a FG layer in the middle. The nanoplates are deposited on a viscoelastic foundation, and the effective material parameters of the FG interlayers are determined using the Mori-Tanaka homogenization model. To specifically examine the influence of surface effect (SE) and scale effect, governing equations are derived from the unified shear deformation theory and Hamilton’s principle, incorporating the theoretical frameworks of surface piezoelectricity theory and nonlocal strain gradient theory. Thereafter, the characteristic equations are analytically solved to obtain numerical effects of wave dispersion relations. The effects of various parameters, such as surface parameters, scale parameters, viscoelastic parameters, and external loads on the wave propagation characteristics are investigated in detail. The piezoelectric SE is related to the scale parameters. Surface density decreased the frequency, and the degree of influence of both surface piezoelectric parameters and residual stress on the frequency decreased rapidly with the increase in the thickness of the piezoelectric layer.
Design and experimental verification of programmable metastructures based on constant force cells
Authors: Zhong Jianhua , Li Jin , Ding Bingxiao , Chen Shih-Chi
Published: November 2024

Mechanical metastructures consisting of periodic cells with adjustable output force charactersitics and ranges have received increasing attention in recent years owing to its unique capability to tune mechanical properties such as stiffness and Poisson’s ratio etc. In this paper, we present the design, simulation, and experimental characterization of a mechanical metastructure that realizes customized constant force output. The metastructure consists of periodic constant force units that are formed by combining a positive and negative stiffness element. Notably, the force unit also contains a unique flexure design with solid and hollow pins to reduce the lateral stress by 50%, which allows for precise control of the output force. By using a programmable design method, the force unit forms 2D and 3D metastructures via parallel and tendem stacking. Simulations were performed to optimize the design and predict the device performance. Finally, experiments were devised and performed to verify the simulation results of the metastructures. The promising results warrant the wide application of the new mechanical metastructure as well as the programmable design method, such as low-pass mechanical filters, noise and vibration cancellation devices etc.
Dynamic damage law and failure modes of layered coal-rock mass under impact loading
Authors: Li Feng , Wang Bo , Sun Xuan , Xu Bo
Published: November 2024

Up to now, most of the structural dynamic analysis is based on the Lagrange system, while the Hamilton system is composed of the phase space composed of the generalized displacement and stress, showing a wonderful symmetry, which opens up a new way for the theoretical research and calculation of dynamics. The physical model of the layered combined coal-rock is constructed by dividing the ‘outburst center’ coal in front of the heading face into the combined layered structure. Based on Hamilton mechanics, the Hamilton canonical equation under symplectic geometry structure is established, combined with Hamilton variational principle and symplectic time subdomain method, the multi-layer symplectic element control equation of coal-rock is established, and the dynamic displacement and stress transfer characteristics at any time can be solved by iterative calculation. The action modes of axial torsional stress, radial principal stress and shear stress of layered coal- rock under impact loading are determined, and the weak layer and interlayer stress transfer dynamic response behavior of layered coal- rock under complex stress conditions are determined. The conclusions are as follows: ①Under static loading, the layered shear stress circle provides the initial condition of damage failure, impact loading acts as an exciting force to trigger the torsion effect, forming the ‘ X ’ -shaped shear line in the radial and axial directions of the interlayer interface, and the boundary produces the ‘ V ’ -shaped dynamic spalling surface. ②The short axis is damaged before the long axis, and the central node is the starting point of instability. The main cracks are formed along the long and short axis respectively, and finally the ‘ O-+ ’ failure mode is formed, which verifies the prominent axial and radial spallation phenomenon. This method avoids the non-conservation of system energy caused by energy dissipation, and will become an effective method to study the dynamic mechanical properties and damage evolution path of coal-rock. It has guiding and reference significance for the theoretical research and prevention technology of coal and rock dynamic disasters.
Effect of DM Interaction in the charging process of a Heisenberg spin chain quantum battery
Authors: K Sanah Rahman , Murugesh S
Published: November 2024

We investigate the charging performance of an anisotropic XYZ model of Heisenberg Spin Chain Quantum Battery (HS QB) along with different components of Dzyaloshinskii-Moriya Interaction (DMI) for three cases - short range, long range and infinite range interactions. We find that the presence of DMI enhances the charging power and total stored energy of the QB considered here, when compared to HS QB in most of the cases, by considering both local and collective charging protocols. The maximum stored energy increases linearly with the number of spins (N). An extensive scaling of maximum charging power with the number of spins is obtained in which the maximum power approaches a scaling exponent α = 1.846 for collective charging of the model consisting of Heisenberg spin chain with Y component of DMI under infinite range interactions. Finally, we optimize the performance of the battery by measuring the quantum energy fluctuations with in the system.
Optical coherence tomography image despeckling based on saliency enhancement and high-order singular value Marchenko-Pastur truncation
Authors: Chen Huaiguang , Wei Wenyu , Zhang Yan
Published: November 2024

Optical Coherence Tomography (OCT) is a high-resolution imaging technique extensively used in various fields, including medical diagnosis. The presence of speckle noise significantly degrades the quality of OCT images. To address this, a novel denoising approach based on High-Order Singular Value Decomposition (HOSVD), along with saliency enhancement and Marchenko-Pastur (MP) truncation, has been proposed. Initially, the method leverages the weighted absolute distance based on variance and information entropy to locate non-local patches that are highly correlated with a given reference block. Following this, a three-dimensional tensor is decomposed via HOSVD and then contracted based on the principles from the MP theorem in random matrix theory. An iterative regularization technique, coupled with a saliency enhancement strategy, is also employed to improve the denoising performance. Experimental results show that the method is comparable to existing advanced denoising algorithms in terms of reducing speckle noise and preserving image details.
On marginals and profiled posteriors for cosmological parameter estimation
Authors: Kerscher Martin , Weller Jochen
Published: November 2024

With several examples and in an analysis of the Pantheon+ supernova
sample we discuss the properties of the marginal posterior distribution
versus the profiled posterior distribution — the profile likelihood in a
Bayesian disguise.
We investigate whether maximisation, as used for the profiling, or
integration, as used for the marginalisation, is more appropriate.
To report results we recommend the marginal posterior distribution.
Dynamic partition of urban network considering congestion evolution based on random walk
Authors: Feng 冯 Zhen-Tong 振通 , Zhang 张 Lele 乐乐 , Wu 吴 Yong-Hong 永洪 , Hu 胡 Mao-Bin 茂彬
Published: November 2024

The successful application of perimeter control of urban traffic system strongly depends on the macroscopic fundamental diagram of the targeted region. Despite intensive studies on the partitioning of urban road networks, the dynamic partitioning of urban regions reflecting the propagation of congestion remains an open question. This paper proposes to partition the network into homogeneous sub-regions based on random walk algorithm. Starting from selected random walkers, the road network is partitioned from the early morning when congestion emerges. A modified Akaike information criterion is defined to find the optimal number of partitions. Region boundary adjustment algorithms are adopted to optimize the partitioning results to further ensure the correlation of partitions. The traffic data of Melbourne city are used to verify the effectiveness of the proposed partitioning method.
SSVEP modulation via non-volitional neurofeedback: an in silico proof of concept
Authors: Estiveira João , Soares Ernesto , Pires Gabriel , Nunes Urbano J , Sousa Teresa , Ribeiro Sidarta , Castelo-Branco Miguel
Published: November 2024

Objective. Neuronal oscillatory patterns are believed to underpin multiple cognitive mechanisms. Accordingly, compromised oscillatory dynamics were shown to be associated with neuropsychiatric conditions. Therefore, the possibility of modulating, or controlling, oscillatory components of brain activity as a therapeutic approach has emerged. Typical non-invasive brain–computer interfaces based on EEG have been used to decode volitional motor brain signals for interaction with external devices. Here we aimed at feedback through visual stimulation which returns directly back to the visual cortex. Approach. Our architecture permits the implementation of feedback control-loops capable of controlling, or at least modulating, visual cortical activity. As this type of neurofeedback depends on early visual cortical activity, mainly driven by external stimulation it is called non-volitional or implicit neurofeedback. Because retino-cortical 40–100 ms delays in the feedback loop severely degrade controller performance, we implemented a predictive control system, called a Smith-Predictor (SP) controller, which compensates for fixed delays in the control loop by building an internal model of the system to be controlled, in this case the EEG response to stimuli in the visual cortex. Main results. Response models were obtained by analyzing, EEG data (n = 8) of experiments using periodically inverting stimuli causing prominent parieto-occipital oscillations, the steady-state visual evoked potentials (SSVEPs). Averaged subject-specific SSVEPs, and associated retina-cortical delays, were subsequently used to obtain the SP controller’s linear, time-invariant models of individual responses. The SSVEP models were first successfully validated against the experimental data. When placed in closed loop with the designed SP controller configuration, the SSVEP amplitude level oscillated around several reference values, accounting for inter-individual variability. Significance. In silico and in vivo data matched, suggesting model’s robustness, paving the way for the experimental validation of this non-volitional neurofeedback system to control the amplitude of abnormal brain oscillations in autism and attention and hyperactivity deficits.
Attention demands modulate brain electrical microstates and mental fatigue induced by simulated flight tasks
Authors: Han Mingxiu , Wang Yuwen , Liu Xinyi , Cheng Xiangxin , Niu Haijun , Liu Tao
Published: November 2024

Objective. Prolonged engagement in tasks with varying attention demands is thought to elicit distinct forms of mental fatigue, potentially indicating variations in neural activity. This study aimed to investigate the association between mental fatigue and changes in electroencephalogram microstate dynamics during tasks with varying attention demands. Approach. In the present study, we employed a 2 × 2 repeated measures ANOVA to analyze the temporal parameters of four distinct microstates (A, B, C, and D) across different levels of attention demands (high vs. low) and mental fatigue (high vs. low) within a controlled flight simulation task involving 17 college students. Main results. Significant variations in mean durations were observed, with microstates A and B exhibiting shorter durations under high fatigue during low attention demands, while their durations increased under high attention demands. Microstate C showed increased occurrences with high fatigue under low attention demands and decreased occurrences under high attention demands. The duration and occurrence of the microstates exhibited different trends throughout the course of mental fatigue, potentially reflecting distinct fatigue-related processes. Significance. These findings establish a link between different types of mental fatigue and microstate dynamics, contributing to a comprehensive understanding of the neural processing mechanisms underlying mental fatigue.
Assessing the impact of alpha particles on thermal confinement in JET D-T plasmas through global GENE-Tango simulations
Authors: Di Siena A. , Garcia J. , Bilato R. , Kirov K. , Varela J. , Bañón Navarro A. , Kim Hyun-Tae , Challis C. , Hobirk J. , Kappatou A. , Lerche E. , Spong D. , Angioni C. , Görler T. , Poli E. , Bergmann M. , Jenko F. ,   JET contributors
Published: November 2024

The capability of the global, electromagnetic gyrokinetic GENE code interfaced with the transport Tango solver is exploited to address the impact of fusion alpha particles (in their dual role of fast particles and heating source) on plasma profiles and performance at JET in the discharges with the highest quasi-stationary peak fusion power during the DTE2 experimental campaigns. Employing radially global nonlinear electromagnetic GENE-Tango simulations, we compare results with/without alpha particles and alpha heating. Our findings reveal that alpha particles have a negligible impact on turbulent transport, with GENE-Tango converging to similar plasma profiles regardless of their inclusion as a kinetic species in GENE. On the other hand, alpha heating is found to contribute to the peaking of the electron temperature profiles, leading to a 1 keV drop on the on-axis electron temperature when alpha heating is neglected in Tango. The minimal impact of alpha particles on turbulent transport in this JET discharge–despite this being the shot with the highest fusion output–is attributed to the low content of fusion alpha in this discharge. To assess the potential impact of alpha particles on turbulent transport in regimes with higher alpha particle density, as expected in ITER and fusion reactors, we artificially increased the alpha particle concentration to levels expected for ITER. By performing global nonlinear GENE standalone simulations, we found that increasing the alpha particle density beyond five times the nominal value lead to significant overall turbulence destabilization. These results demonstrate that an increased alpha particle concentration can significantly impact transport properties under simulated JET experimental conditions. However, these findings cannot be directly extrapolated to ITER due to the substantial differences in parameters such as plasma size, magnetic field, plasma current, and thermal pressure.
High-Temperature Chip-Scale Atomic Clock
Authors: Ha Li-Chung , Noble Jay , Newell Bruce , Lutwak Robert
Published: November 2024

We present the development of alkali-alloy-based vapor cells for operating a cesium-based Chip-Scale Atomic Clock (CSAC) at environmental temperatures up to 105 °C. Leveraging Raoult’s Law for a mixture of potassium and cesium metal, we have demonstrated vapor pressure suppression equivalent to 25 °C, allowing a CSAC to operate at higher temperatures with minimal degradation of performance or power consumption.
Developments to improve the stability of optical lattice clocks
Authors: Bize S. , Fang B. , Le Coq Y. , Le Targat R. , Lodewyck J. , Pottie P.-E. , Shang H. , Zyskind C.
Published: November 2024

We present several developments aimed at improving the stability of optical lattice clocks. First, we present our developments of an optical lattice clock using neutral mercury. We mention recent advances made with the fermionic isotope 199Hg. We also mention our work aimed at using bosonic isotopes, which offer the possibility to circumvent the relatively short lifetime of the upper clock state in 199Hg. Second, we present our work on a non-destructive detection in a Sr optical lattice clock. We describe developments that brought the detection scheme from the classical non-destructive regime to the quantum non-destructive regime. Our detection scheme is practical and has the capability to the used beyond proving the principle. Finally, we present our work on laser stabilization using spectral hole burning in a Eu3+:Y2SiO5 crystal at cryogenic temperatures. We describe our development of low noise interrogation based on digital IQ modulation and detection that can probe multiple spectral features simultaneously, as well as several investigations towards fluctuating environmental factors. These advances, individually or combined for example with spectral purity transfer with combs and composite clock approaches, shall bring significant progress in clock stability and accuracy.
Pure frequency-based dispersive spectroscopy
Authors: Cygan A. , Bielska K. , Charczun D. , Kowzan G. , Nishiyama A. , Wcisło P. , Wójtewicz S. , Zaborowski M. , Masłowski P. , Lisak D. , Ciuryło R. , Fleisher A. J. , Gillis K. A. , Hodges J. T. , Voumard T. , Wilidi T. , Herr T. , Brasch V.
Published: November 2024

Dispersion spectroscopy based on frequency measurement of the high finesse optical cavity mode shifts induced by the presence of a gas medium with absorption resonances is an attractive alternative to standard absorptive spectroscopy. The main advantage of such pure frequency-based dispersive spectroscopy technique is the unique combination of sensitivity and accuracy. High sensitivity is ensured by high finesse optical cavities providing extremely long effective optical paths. On the other hand, high accuracy is provided by frequency measurement cavity mode shift. This makes this technique free from systematic errors coming from the non-linearity of light intensity measurements, which is one of the limiting factors in typical absorptive spectroscopy. We review several realizations of dispersive spectroscopy in high finesse optical cavities from Doppler-free to broadband. These techniques are especially useful for studying weak molecular transitions applicable in testing fundamental physics, gas metrology, spectroscopic thermometry, and a new generation of spectroscopic databases.
Computational assessment of mass-diffusive compressible fluids flows models
Authors: Bodnár Tomáš , Fraunié Philippe
Published: November 2024

This paper deals with the numerical simulations using novel, non-standard models applicable to flow of compressible viscous fluid. Instead of the classical compressible Navier-Stokes-Fourier system, two other variants and approximations are used. Models are solved numerically by high resolution finite-difference scheme in two-dimensional test cases, trying to point out and document the mutual differences in the predictions of different models. The numerical simulations performed for the Kelvin-Helmhotz instability and the double-periodic shear layer presented and discussed. The comparison shows a very good agreement of the model predictions, with only minor discrepancies in the divergence of velocity field in the proximity of high solution gradients.