bluuebunny/crossref_metadata_2025 huggingface dataset:
An ultrastable 1397-nm laser stabilized by a crystalline-coated room-temperature cavity
Authors: Zhu Xian-Qing , Cui Xing-Yang , Kong De-Quan , Yu Hai-Wei , Zhai Xiao-Min , Zheng Ming-Yang , Xie Xiu-Ping , Zhang Qiang , Jiang Xiao , Zhang Xi-Bo , Xu Ping , Dai Han-Ning , Chen Yu-Ao , Pan Jian-Wei
Published: August 2024

State-of-the-art optical cavities are pivotal in pushing the envelope of laser frequency stability below 10−16. This is often achieved by extending the cavity length or cooling the system to cryogenic temperatures to reduce the thermal noise floor. In our study, we present a 30-cm-long cavity that operates at room temperature and is outfitted with crystalline coatings. The system has a predicted ultralow thermal noise floor of 4.4 × 10−17, comparable to what is observed in cryogenic silicon cavities. A 1397-nm laser is stabilized in this advanced cavity, and the stable frequency is then transferred to the clock transition in strontium optical lattice clocks via a frequency-doubling process. We have meticulously minimized and assessed the technical noise contributions through comparisons with an ultrastable reference laser that is locked to a commercially available 30-cm cavity. The frequency instability of the system is rigorously evaluated using a three-cornered-hat method. The results demonstrate that the laser frequency instability remains below 2 × 10−16 for averaging times ranging from 1 to 50 s. These findings underscore the significant potential of room-temperature cavities with crystalline coatings in high-precision metrology and pave the way for further improvements in optical lattice clocks.
First-principles investigation of oxidized Si- and Ge-terminated diamond (100) surfaces
Authors: Gomez H. , Cruz J. , Milne C. , Debnath T. , Birdwell A. G. , Garratt E. J. , Pate B. B. , Rudin S. , Ruzmetov D. A. , Weil J. D. , Shah P. B. , Ivanov T. G. , Lake R. K. , Groves M. N. , Neupane M. R.
Published: August 2024

Diamond is a semiconductor material with remarkable structural, thermal, and electronic properties that has garnered significant interest in the field of electronics. Although hydrogen (H) and oxygen (O) terminations are conventionally favored in transistor designs, alternative options, such as silicon (Si) and germanium (Ge), are being explored because of their resilience to harsh processing conditions during fabrication. Density-functional theory was used to examine the non-oxidized and oxidized group-IV (Si and Ge)-terminated diamond (100) surfaces. The (3 × 1) reconstructed surfaces feature an ether configuration and show relative stability compared with the bare surface. Hybrid-functional calculations of the electronic properties revealed reduced fundamental bandgaps (<1 eV) and lower negative electron affinities (NEAs) than those of H-terminated diamond surfaces, which is attributed to the introduction of unoccupied Si (Ge) states and the depletion of negative charges. Furthermore, oxidation of these surfaces enhanced the stability of the diamond surfaces but resulted in two structural configurations: ether and ketone. Oxidized ether configurations displayed insulating properties with energy gaps of ∼4.3 ± 0.3 eV, similar to H-terminated diamond (100) surfaces, whereas bridged ether configurations exhibited metallic properties. Oxidization of the metallic ketone configurations leads to the opening of relatively smaller gaps in the range of 1.1–1.7 eV. Overall, oxidation induced a shift from NEAs to positive electron affinities, except for the reverse-ordered ketone surface with an NEA of −0.94 eV, a value comparable to the H-terminated diamond (100) surfaces. In conclusion, oxidized group-IV-terminated diamond surfaces offer enhanced stability compared to H-terminated surfaces and display unique structural and electronic properties that are influenced by surface bonding.
Observation of transient aspects of self-sustained oscillations and the role of parallel capacitance in VO2-based planar devices
Authors: Kidokoro Junpei , Mian Md. Suruz , Hoque Lamisa , Yu Peng , Okimura Kunio , Nakanishi Toshihiro
Published: August 2024

Self-sustained electrical oscillations (SEOs) in VO2 films have attracted considerable attention owing to their potential to emulate spiking pulses in neuromorphic circuits. However, triggering stable SEOs and the controlling oscillation frequency remain challenging because the details of circuit operation with VO2-based devices are not yet well understood. In this study, we propose a method to observe SEOs stably in a VO2-based planar device with Au/Ti facing electrodes by introducing a 50 Hz sinusoidal voltage from a curve tracer. The transient aspects, including the onset and collapse of the SEO, were captured, providing clarity on the oscillation frequency range and circuit conditions for the SEOs, which are closely correlated with the device temperature. It became clear that the parallel capacitance not only determined the oscillation frequency but also controlled the current through VO2 just after the insulator–metal transition of VO2, playing a role in triggering stable oscillations. We also successfully observed the transient aspects from in-phase to anti-phase synchronized oscillations in the coupled oscillations. This study advances the experimental procedures and applications of SEOs in VO2-based planar devices.
Erosion and impurity transport for the edge localized mode suppression window in KSTAR
Authors: Navarro Marcos , Van Blarcum Jonathan , Frerichs Heinke , Romazanov Juri , Kirschner Andreas , Park Jong-Kyu , Yang Seong-Moo , Schmitz Oliver
Published: August 2024

A 3D analysis of plasma wall interactions and global impurity transport for the edge localized mode suppression window in KSTAR during H-Mode discharges has shown that carbon erosion at the divertor plates is a strong function of the resonant magnetic perturbation (n = 1) coil current and relative phasing. The Generalized Perturbation Equilibrium Code was used to determine a realistic initial perturbed plasma equilibrium, and EMC3-EIRENE was used to calculate the resulting scrape-off layer plasma used in this study as a fixed background for the ERO2.0 plasma–material interaction model. The resulting transport leads to deposition of impurities along the targets positioned at the high-field side of the device. An attempt at calculating the resulting effective charge state has demonstrated a similar dependence on the perturbation coil current and has been able to determine a window for the experimentally observed values of Zeff by including contributions of all ionized carbon charge states and deuterium.
Effect of the geometrical parameters of an X-pinch on the characteristics of the soft x-ray source
Authors: Artyomov A. P. , Oreshkin V. I. , Rousskikh A. G. , Rybka D. V. , Fedyunin A. V. , Chaikovsky S. A. , Ratakhin N. A.
Published: August 2024

It was studied how the geometrical parameters of an X-pinch (the angle of inclination of the wires to the X-pinch vertical axis and the length of the electrode gap) affected the number of hot spots, formed in the region of the X-pinch neck, and the x-ray yield. The experiment was performed on the XPG-3 compact current pulse generator (180 kA, 180 ns). The highest values of the x-ray energy per pulse were observed when the angle of inclination of the wires to the X-pinch load vertical axis (z-axis) was 40°–45° at an electrode gap length of 6–7 mm. In these cases, the energy of the x-ray pulse in the spectral range hν = 1.5–5 keV was 1.1 ± 0.4 J. The angle of inclination of the X-pinch wires to the z-axis equal to 45° was a threshold above which the conditions for the formation of a hot spot changed significantly. It was observed that, regardless of the wire inclination angle, two hot spots formed with a high degree of probability in the neck region at the final stage of implosion.
A novel racetrack Blumlein pulse forming line
Authors: Zhang Hanwen , Pan Zilong , Zhang Renjie , Li Rupei , Chen Jie , Gao Jingming , Chen Rong , Cheng Xinbing
Published: August 2024

Pulse forming lines (PFL) are widely applied in high-power pulsed power generators due to their high energy density and great ability with square waveform modulation. However, the three-cylinder coaxial Blumlein line (tPFL), a commonly used PFL structure, has low energy efficiency due to the difference in impedance of the outer and inner lines. In order to increase the outer line impedance and improve the output waveform of the PFL, a racetrack Blumlein pulse forming line (r-B PFL), formed by two inner cylinders, two middle cylinders, and one outer cylinder that resembles a runway shape, is proposed in this paper. The glycerin energy storage technology and the spiral line technology were applied in the PFL. Moreover, the r-B PFL was tested experimentally after its construction, yielding a satisfactory result. The PFL structure in which multiple middle cylinders share the same outer cylinder achieves a higher outer line impedance, leading to a high energy efficiency of the PFL, which contributes to the PFL development trend toward compactness and miniaturization.
Inverse aspect-ratio expanded tokamak equilibria
Authors: Fitzpatrick R.
Published: August 2024

Following Greene et al. [Phys. Fluids 14, 671 (1971)] and Connor et al. [Phys. Plasmas 31, 577 (1988); Plasma Phys. Control. Fusion 34, 161 (1992); and Nucl. Fusion 33, 1533 (1993)], the Grad-Shafranov equation for an axisymmetric tokamak plasma equilibrium is solved via an expansion in the, supposedly small, inverse aspect-ratio of the plasma, ϵ. The displacements of equilibrium magnetic flux-surfaces due to plasma shaping are assumed to be O(ϵ) smaller than the minor radii of the surfaces, but no other restriction is placed on the nature of the shaping. The solution of the Grad-Shafranov equation is matched to a vacuum solution that extends to infinity, and consists of an expansion in toroidal functions. The external poloidal magnetic field generated by a finite set of discrete external poloidal magnetic field-coils is calculated, and incorporated into the toroidal function expansion. In this manner, the shape of a large aspect-ratio tokamak plasma is directly related to the currents flowing in the external poloidal field-coils. Finally, a pedestal in the plasma pressure, and the associated spike in the bootstrap current, are incorporated into the model.
Strength of 2D glasses explored by machine-learning force fields
Authors: Shi Pengjie , Xu Zhiping
Published: August 2024

The strengths of glasses are intricately linked to their atomic-level heterogeneity. Atomistic simulations are frequently used to investigate the statistical physics of this relationship, compensating for the limited spatiotemporal resolution in experimental studies. However, theoretical insights are limited by the complexity of glass structures and the accuracy of the interatomic potentials used in simulations. Here, we investigate the strengths and fracture mechanisms of 2D silica, with all structural units accessible to direct experimental observation. We develop a neural network force field for fracture based on the deep potential-smooth edition framework. Representative atomic structures across crystals, nanocrystalline, paracrystalline, and continuous random network glasses are studied. We find that the virials or bond lengths control the initialization of bond-breaking events, creating nanoscale voids in the vitreous network. However, the voids do not necessarily lead to crack propagation due to a disorder-trapping effect, which is stronger than the lattice-trapping effect in a crystalline lattice, and occurs over larger length and time scales. Fracture initiation proceeds with void growth and coalescence and advances through a bridging mechanism. The fracture patterns are shaped by subsequent trapping and cleavage steps, often guided by voids forming ahead of the crack tip. These heterogeneous processes result in atomically smooth facets in crystalline regions and rough, amorphous edges in the glassy phase. These insights into 2D crystals and glasses, both sharing SiO2 chemistry, highlight the pivotal role of atomic-level structures in determining fracture kinetics and crack path selection in materials.
Weakly nonlinear incompressible Rayleigh–Taylor–Kelvin–Helmholtz instability in plane geometry
Authors: Zou Zhen-Qi , Wu Jun-Feng , Yang Guo-Wei , Wang Li-Feng , Zhang Wei-Yan
Published: August 2024

A weakly nonlinear theoretical model is established for the two-dimensional incompressible Rayleigh–Taylor–Kelvin–Helmholtz instability (RT–KHI). The evolution of the perturbation interface is analytically studied by the third-order solution of the planar RT–KHI induced by a single-mode surface perturbation. The difference between the weakly nonlinear growth for Rayleigh–Taylor instability (RTI), Kelvin–Helmholtz instability (KHI), and RT–KHI in plane geometry is discussed. The trend of bubble and spike amplitudes with the Atwood number and the Richardson number is discussed in detail. The bubble and spike amplitudes of RT–KHI change from the KHI case to the RTI case as the Richardson number increases. The deflecting distance of bubble and spike vertices becomes smaller compared to the KHI case as the Richardson number increases. The dependence of the nonlinear saturation amplitude of RT–KHI on the Atwood number, the Richardson number, and the initial perturbation is obtained. The Richardson number is as vital to the nonlinear saturation amplitude as the Atwood number. It is found that the variation of the nonlinear saturation amplitude with the Atwood number at different Richardson numbers is divided into three parts, namely, “RTI-like part,” “transition part,” and “KHI-like part.” In the transition part, the trend of the nonlinear saturation amplitude increasing with the Atwood number is completely opposite to the RTI and KHI cases. Finally, the theory is compared to the numerical simulation under identical initial conditions and displays good correspondence in the linear and weakly nonlinear stages.
Insight into properties of sizable glass former from volumetric measurements
Authors: Rams-Baron Marzena , Błażytko Alfred , Casalini Riccardo , Paluch Marian
Published: August 2024

Sizable glass formers feature numerous unique properties and potential applications, but many questions regarding their glass transition dynamics have not been resolved yet. Here, we have analyzed structural relaxation times measured as a function of temperature and pressure in combination with the equation of state obtained from pressure–volume–temperature measurements. Despite evidence from previous dielectric studies indicating a remarkable sensitivity of supercooled dynamics to compression, and contrary to intuition, our results demonstrated the proof for the almost equivalent importance of thermal energy and free volume fluctuations in controlling reorientation dynamics of sizable molecules. The found scaling exponent γ = 3.0 and Ev/Ep ratio of 0.6 were typical for glass-forming materials with relaxation dynamics determined by both effects with a minor advantage of thermal fluctuations involvement. It shows that the high values of key parameters characterizing the sensitivity of the glass transition dynamics to pressure changes, i.e., activation volume ΔV and dTg/dP, are not a valid premise for a remarkable contribution of volume to glass transition dynamics.
Vibrational frequency fluctuations of poly(N,N-diethylacrylamide) in the vicinity of coil-to-globule transition studied by two-dimensional infrared spectroscopy and molecular dynamics simulations
Authors: Fujii Yuki , Ioka Hikaru , Minamoto Chihiro , Kurisaki Ikuo , Tanaka Shigenori , Ohta Kaoru , Tominaga Keisuke
Published: August 2024

Poly(N,N-diethylacrylamide) (PdEA), one of the thermoresponsive polymers, in aqueous solutions has attracted much attention because of its characteristic properties, such as coil-to-globule (CG) transition. We performed two-dimensional infrared spectroscopy and molecular dynamics (MD) simulations to understand the hydration dynamics in the vicinity of the CG transition at the molecular level via vibrational frequency fluctuations of the carbonyl stretching modes in the side chains of PdEA. Furthermore, N,N-diethylpropionamide, a repeating monomer unit of PdEA, is also investigated for comparison. From decays of the frequency–frequency time correlation functions (FFTCFs) of the carbonyl stretching modes, we consider that inhomogeneity of the hydration environments originates from various backbone configurations of PdEA. The degree of the inhomogeneity depends on temperature. Hydration water molecules near the carbonyl groups are influenced by the confinements of the polymers. The restricted reorientation of the embedded water, the local torsions of the backbone, and the rearrangement of the whole structure contribute to the slow spectral diffusion. By performing MD simulations, we calculated the FFTCFs and dynamical quantities, such as fluctuations of the dihedral angles of the backbone and the orientation of the hydration water molecules. The simulated FFTCFs match well with the experimental results, indicating that the retarded water reorientations via the excluded volume effect play an important role in the vibrational frequency fluctuations of the carbonyl stretching mode. It is also found the embedded water molecules are influenced by the local torsions of the backbone structure within the time scales of the spectral diffusion.
Optical properties of ZnO nanocrystals under photo-induced electron doping
Authors: Yamamoto Sekika , Ushida Tenta
Published: August 2024

The absorption and photoluminescence (PL) spectra of negatively photodoped ZnO nanocrystals dispersed in ethanol are measured under a stepwise photodoping process at room temperature. The spectra are measured almost simultaneously at each photodoping level and compared in detail to discuss the origin of the spectral change. The redshift of the PL spectrum and the increase of its intensity are clearly observed in the early stage of photodoping and are attributed to the trion luminescence. The PL spectrum is found to split into two peaks for highly photodoped nanocrystals. The cause of the splitting is discussed in terms of its dependence on the nanocrystal size.
Gallium oxide semiconductor-based large volume ultrafast radiation hard spectroscopic scintillators
Authors: Datta A. , Mei H. , Lebedinsky A. , Halasyamani P. Shiv. , Motakef S.
Published: August 2024

We report on the development of the first-ever inorganic radiation-hard moisture-insensitive large volume spectroscopic semiconductor-based scintillator with less than 2 ns decay time and light yields as high as 8000 ph/MeV. Despite extensive research into scintillator materials, the quest for an ideal scintillator combining ultrafast decay times (akin to BaF2 and Yb-doped scintillators such as Lu2O3:Yb), high light yields (exceeding 2000 photons per MeV), spectroscopic capabilities, and exceptional radiation hardness remain unfulfilled. In this study, we demonstrate and report for the first time the viability of large-volume (up to 20 mm thickness) gallium oxide (β-Ga2O3) semiconductor-based scintillators for applications requiring these properties. These β-Ga2O3 scintillators were grown using the fast turnaround (∼2 days) crucible-free optical float zone (FZ) technique. The high light yield and ultrafast decay time of these high-purity n-type semiconductors with free carrier concentration of 6 × 1017 cm−3 are attributed to native defects, specifically oxygen vacancies (VO) and gallium–oxygen vacancy pairs (VGa–VO), generated during optimized FZ growth. The ultrafast decay, along with high light yield, enables excellent timing resolution and high count rate detection for applications like time-of-flight positron emission tomography, physics experiments, and nuclear safety. The radiation hardness of these devices has been documented in a separate publication.
Featurizing Koopman mode decomposition for robust forecasting
Authors: Aristoff David , Copperman Jeremy , Mankovich Nathan , Davies Alexander
Published: August 2024

This article introduces an advanced Koopman mode decomposition (KMD) technique—coined Featurized Koopman Mode Decomposition (FKMD)—that uses delay embedding and a learned Mahalanobis distance to enhance analysis and prediction of high-dimensional dynamical systems. The delay embedding expands the observation space to better capture underlying manifold structures, while the Mahalanobis distance adjusts observations based on the system’s dynamics. This aids in featurizing KMD in cases where good features are not a priori known. We show that FKMD improves predictions for a high-dimensional linear oscillator, a high-dimensional Lorenz attractor that is partially observed, and a cell signaling problem from cancer research.
Contour shape dependency of circulation statistics in homogeneous and isotropic turbulence
Authors: Iyer Kartik P. , Moriconi L.
Published: August 2024

Statistical moments of the turbulent circulation are complex geometry-dependent functionals of closed oriented contours and present a hard challenge for theoretical understanding. Conveniently defined circulation moment ratios, however, are empirically known to have appreciable geometric dependency only at lower moment orders and for contours that are sized near the bottom of the inertial range, in the situation where they span minimal surfaces of equivalent areas. Resorting to ideas addressed in the framework of the vortex gas model of circulation statistics, which integrates structural and multifractal aspects of the turbulent velocity field, we are able to reproduce, with reasonable accuracy, the observed contour shape dependency of circulation moment ratios, up to high order statistics. A key phenomenological point in our discussion is the assumption that the energy dissipation field, closely related to the local density of thin vortex tubes, is sharply bounded from above at finite Reynolds numbers.
Analytical solutions to (modified) Korteweg–de Vries–Zakharov–Kuznetsov equation and modeling ion-acoustic solitary, periodic, and breather waves in auroral magnetoplasmas
Authors: Alhejaili Weaam , Roy Subrata , Raut Santanu , Roy Ashim , Salas Alvaro H. , Aboelenen Tarek , El-Tantawy S. A.
Published: August 2024

This article investigates the propagation of different types of nonlinear ion-acoustic waves, including periodic waves, solitons, and breathers in non-Maxwellian magnetized plasma. The plasma model consists of inertial cold ions, inertialess cold electrons that obey a Boltzmann distribution, and inertialess non-Maxwellian hot electrons that follow the generalized (r, q) distribution. The reductive perturbation technique is utilized to obtain the Korteweg–de Vries–Zakharov–Kuznetsov equation (KdV-ZK) from the fluid equations that govern plasma dynamics. Furthermore, the modified KdV-ZK equation is derived due to the limited capability of the KdV-ZK model to represent the dynamics of the nonlinear structures at specific critical values of the relevant physical variables in the investigated system. The periodic solutions to the two models (KdV-ZK and mKdV-ZK models) are derived using Jacobi elliptic functions. This approach directly links periodic waves (cnoidal waves) and soliton solutions. Hirota's bilinear method generates breathers for both models. Finally, we examine the quantitative understanding of the effects of several physical parameters replicated by the Swedish satellite Viking incorporated in the model. The findings reported in this study enhance our comprehension of the properties of the electron distribution function's high- and low-energy segments and the development of periodic, soliton, multi-soliton, and breather phenomena in space and astrophysical plasmas.
Electrical activation of insulator-to-metal transition in vanadium dioxide single-crystal nanobeam and their high-frequency switching performances
Authors: Orlianges J.-C. , Allegret O. , Sirjita E.-N. , Masson A. , Boulle A. , Théry V. , Tardif S. , Micha J. S. , Crunteanu A.
Published: August 2024

We demonstrate the integration of vanadium dioxide single-crystal nanobeams fabricated by modified vapor–liquid–solid method as electrical switching elements into a radio-frequency transmission line and evaluate the performances of the overall device in modulating the transmission of the conveyed RF electromagnetic waves. The switching capability of the RF device is based on the metal–insulator transition of VO2 nanobeams, with an on/off electrical switching ratio of 104, i.e., resistance modulation from more than 106Ω when the wires are in the insulating state to only ≈20Ω when they are in the metal-like state. The thermal and electrical activation of the VO2 wires between the two dissimilar states is resulting in RF switching performances characterized by more than 15 dB change in the transmission coefficient of the device over the 100 MHz–24  GHz frequency domain.
Analysis of wave characteristics in the North Pacific Ocean based on the fusion of multi-source satellite altimetry
Authors: Gao Huijun , Liang Bingchen , Yang Hongbin , Shao Zhuxiao
Published: August 2024

Regional analysis of wave characteristics is crucial for ocean engineering planning and marine disaster protection. However, current wave observation methods have limitations in capturing sufficient coverage and resolution of wave field data, specifically significant wave height (SWH). Thus, we fuse multi-source satellite altimeter data using four fusion methods to generate daily SWH fields with a spatial resolution of 0.125° × 0.125° over the North Pacific Ocean (NPO). The results show that the fused SWHs exhibit a consistent spatial distribution pattern similar to the product provided by Archiving, Validation, and Interpretation of Satellite Oceanographic Data. Considering the spatial and temporal variation characteristics of the along-track data, the inverse distance weighting-based spatiotemporal fusion (IDW-ST) method outperforms other fusion methods compared to buoy measurements. Building upon the IDW-ST method, we fuse multi-source satellite altimetry data from 2016 to 2020 and analyze the regional spatial patterns and variations of waves in the NPO. Waves in this region are primarily influenced by monsoons and significantly regulated by extreme weather systems, such as tropical cyclones (TCs). Seasonal variations in wave characteristics may be linked to the frequency and tracks of TCs, with distinctive local features observed in representative zones. For example, the probability distribution of SWHs in the NPO exhibits a trailing pattern with significant deviations from the main SWHs, particularly during winter. Additionally, a heavy-tailed distribution is observed in the central high-latitude zone, except during summer. These patterns indicate the frequency and severity of extreme wave events in these zones.
Adaptive grid-forming photovoltaic inverter control strategy based on fuzzy algorithm
Authors: Wang Chenzhao , Cao Kan , Hu Pan
Published: August 2024

In order to enhance the support capability of photovoltaic inverters for new energy microgrid systems, grid-forming control technology has attracted widespread attention, with Virtual Synchronous Generator (VSG) emerging as a research frontier. This paper integrates hybrid energy storage systems with photovoltaic generation to provide stable voltage support and power compensation for the system. In addition, leveraging the variability of the virtual parameters J and D in traditional VSGs, an adaptive grid-forming photovoltaic inverter control strategy based on fuzzy algorithm is proposed. Furthermore, to reduce the frequency deviation caused by load transients during islanding operation, an adaptive droop coefficient based on frequency power limits is introduced. Finally, simulations are conducted under grid-connected and islanded conditions to compare three control methods: fixed parameter control, traditional adaptive control, and the proposed adaptive with fuzzy control. The results demonstrate that integrating adaptive droop coefficients with fuzzy control can effectively improve the frequency stability and dynamic response capability of microgrids.
MXene-reinforced bioactive polymer hydrogels for biomedical applications
Authors: Gu Guanghui , Chen Xue , Wei Gang , Xu Mingjin
Published: August 2024

MXenes, a novel class of two-dimensional (2D) materials, have attracted considerable attention in various fields, especially in drug delivery, wound healing, bone tissue engineering, biosensing, and cancer treatment. Thanks to their remarkable physicochemical properties, MXenes hold great promise for biomedical applications. Concurrently, hydrogels composed of polymers have been extensively utilized in biomedical contexts. The unique properties of MXenes facilitate their integration into various bioactive hydrogels with enhanced functions and properties, thereby endowing the composites with multifunctional capabilities. MXene-reinforced polymer hydrogels (MRPHs) synergistically combine the advantageous characteristics of both MXenes and hydrogels, making them highly adaptable for integration with other theranostic strategies in medical applications. In this comprehensive review, we demonstrate recent advances in the design and synthesis of MRPHs for biomedical applications. Specifically, we introduce the unique functions and properties of MRPHs and analyze the methods for tailoring the functions of MRPHs by incorporating them with other active components, including functional molecules, 2D materials, metal ions, natural polymers, and drugs/genes. We then discuss the biomedical applications of the designed bioactive MRPHs in wound healing, tissue engineering, biosensors, and cancer therapy. We hope that this work provides valuable guidance and inspiration for readers to develop novel MRPHs for advanced applications.
Human adolescent brain similarity development is different for paralimbic versus neocortical zones
Authors: Dorfschmidt Lena , Váša František , White Simon R. , Romero-García Rafael , Kitzbichler Manfred G. , Alexander-Bloch Aaron , Cieslak Matthew , Mehta Kahini , Satterthwaite Theodore D. ,   The NSPN Consortium, Bethlehem Richard A. I. , Seidlitz Jakob , Vértes Petra E. , Bullmore Edward T. , Bullmore Edward , Dolan Raymond , Goodyer Ian , Fonagy Peter , Jones Peter , Moutoussis Michael , Hauser Tobias , Neufeld Sharon , Romero-Garcia Rafael , St Clair Michelle , Vértes Petra , Whitaker Kirstie , Inkster Becky , Prabhu Gita , Ooi Cinly , Toseeb Umar , Widmer Barry , Bhatti Junaid , Villis Laura , Alrumaithi Ayesha , Birt Sarah , Bowler Aislinn , Cleridou Kalia , Dadabhoy Hina , Davies Emma , Firkins Ashlyn , Granville Sian , Harding Elizabeth , Hopkins Alexandra , Isaacs Daniel , King Janchai , Kokorikou Danae , Maurice Christina , McIntosh Cleo , Memarzia Jessica , Mills Harriet , O’Donnell Ciara , Pantaleone Sara , Scott Jenny , Kiddle Beatrice , Polek Ela , Fearon Pasco , Suckling John , van Harmelen Anne-Laura , Kievit Rogier , Chamberlain Sam , Bethlehem Richard A.I.
Published: August 2024

Adolescent development of human brain structural and functional networks is increasingly recognized as fundamental to emergence of typical and atypical adult cognitive and emotional processes. We analysed multimodal magnetic resonance imaging (MRI) data collected from N

∼

300 healthy adolescents (51%; female; 14 to 26 y) each scanned repeatedly in an accelerated longitudinal design, to provide an analyzable dataset of 469 structural scans and 448 functional MRI scans. We estimated the morphometric similarity between each possible pair of 358 cortical areas on a feature vector comprising six macro- and microstructural MRI metrics, resulting in a morphometric similarity network (MSN) for each scan. Over the course of adolescence, we found that morphometric similarity increased in paralimbic cortical areas, e.g., insula and cingulate cortex, but generally decreased in neocortical areas, and these results were replicated in an independent developmental MRI cohort (N

∼

304). Increasing hubness of paralimbic nodes in MSNs was associated with increased strength of coupling between their morphometric similarity and functional connectivity. Decreasing hubness of neocortical nodes in MSNs was associated with reduced strength of structure–function coupling and increasingly diverse functional connections in the corresponding fMRI networks. Neocortical areas became more structurally differentiated and more functionally integrative in a metabolically expensive process linked to cortical thinning and myelination, whereas paralimbic areas specialized for affective and interoceptive functions became less differentiated, as hypothetically predicted by a developmental transition from periallocortical to proisocortical organization of the cortex. Cytoarchitectonically distinct zones of the human cortex undergo distinct neurodevelopmental programs during typical adolescence.
Riemannian geometry for efficient analysis of protein dynamics data
Authors: Diepeveen Willem , Esteve-Yagüe Carlos , Lellmann Jan , Öktem Ozan , Schönlieb Carola-Bibiane
Published: August 2024

An increasingly common viewpoint is that protein dynamics datasets reside in a nonlinear subspace of low conformational energy. Ideal data analysis tools should therefore account for such nonlinear geometry. The Riemannian geometry setting can be suitable for a variety of reasons. First, it comes with a rich mathematical structure to account for a wide range of geometries that can be modeled after an energy landscape. Second, many standard data analysis tools developed for data in Euclidean space can be generalized to Riemannian manifolds. In the context of protein dynamics, a conceptual challenge comes from the lack of guidelines for constructing a smooth Riemannian structure based on an energy landscape. In addition, computational feasibility in computing geodesics and related mappings poses a major challenge. This work considers these challenges. The first part of the paper develops a local approximation technique for computing geodesics and related mappings on Riemannian manifolds in a computationally feasible manner. The second part constructs a smooth manifold and a Riemannian structure that is based on an energy landscape for protein conformations. The resulting Riemannian geometry is tested on several data analysis tasks relevant for protein dynamics data. In particular, the geodesics with given start- and end-points approximately recover corresponding molecular dynamics trajectories for proteins that undergo relatively ordered transitions with medium-sized deformations. The Riemannian protein geometry also gives physically realistic summary statistics and retrieves the underlying dimension even for large-sized deformations within seconds on a laptop.
A corpus-pragmatic analysis of linguistic democratisation in the British Hansard
Authors: Hiltunen Turo , Vartiainen Turo
Published: August 2024

In this article, we investigate changes in British parliamentary discourse by using the Hansard Corpus
(1803–2005). Our first goal is to determine whether parliamentary speeches have become colloquialised by studying frequency
changes of select features associated with informal spoken language. Second, by analysing data from the House of Commons and the
House of Lords separately, we show that the texts from the two Houses should be considered distinct sub-registers, each with their
own conventions and development paths. Finally, we analyse a pattern that seems particularly relevant to parliamentary debates:
one where speakers imply disagreement by referring to their peers in the third person, thus circumventing a parliamentary
regulation whereby speakers are prohibited from addressing one another directly. Our findings support the idea of an ongoing
colloquialisation/democratisation trend affecting parliamentary discourse while also suggesting that this process is not entirely
transparent in the written record because of editorial interference.
Women’s voices in the public sphere
Authors: Bös Birte
Published: August 2024

As alternative media, suffrage periodicals played an important role in women’s fight for universal suffrage, which
marked a milestone on the road to democracy. Opening up a space for women in public discourse, these papers shaped and were shaped
by processes of democratisation. This study explores how they balanced informative, propagandistic and commercial functions, and
how women positioned themselves and others as social actors in the context of the movement, challenging gender ideologies. In line
with Rühlemann and Aijmer’s (2015) notion of corpus pragmatics, the study combines the
assets of corpus-linguistic methods, e.g., by drawing on keywords as pointers to relevant areas of interest, with a pronounced
qualitative perspective, complementing the search results by features demanding manual analysis and discussing the findings in
their socio-historical context.
Importance of gas heating in capacitively coupled radiofrequency plasma-assisted synthesis of carbon nanomaterials
Authors: Nikhar Tanvi , Basu Sankhadeep , Abe Shota , Yatom Shurik , Raitses Yevgeny , Anthony Rebecca , Baryshev Sergey V
Published: August 2024

In pursuit of diamond nanoparticles, a capacitively-coupled radio frequency flow-through plasma reactor was operated with methane-argon gas mixtures. Signatures of the final product obtained microscopically and spectroscopically indicated that the product was an amorphous form of graphite. This result was consistent irrespective of combinations of the macroscopic reactor settings. To explain the observed synthesis output, measurements of C2 and gas properties were carried out by laser-induced fluorescence and optical emission spectroscopy. Strikingly, the results indicated a strong gas temperature gradient of 100 K per mm from the center of the reactor to the wall. Based on additional plasma imaging, a model of hot constricted region (filamentation region) was then formulated. It illustrated that, while the hot constricted region was present, the bulk of the gas was not hot enough to facilitate diamond sp
3 formation: characterized by much lower reaction rates, when compared to sp
2, sp
3 formation kinetics are expected to become exponentially slow. This result was further confirmed by experiments under identical conditions but with a H2/CH4 mixture, where no output material was detected: if graphitic sp
2 formation was expected as the main output material from the methane feedstock, atomic hydrogen would then be expected to etch it away in situ, such that the net production of that sp
2-hybridized solid material is nearly a zero. Finally, the crucial importance of gas heating was corroborated by replacing RF with microwave source whereby facile sp
3 production was attained with H2/CH4 gas mixture.
Optimizing additive Y2O3 concentration for improving corrosion resistance of ceramic coatings formed by plasma electrolytic oxidation on Zr-4 alloy
Authors: Ajiriyanto Maman Kartaman , Anawati Anawati
Published: August 2024

The corrosion resistance of ceramic coatings developed by plasma electrolytic oxidation (PEO) can be improved by embedding particles. Optimizing the concentration of particles in the electrolyte is essential to obtain the best coating performance. This work aims to optimize the concentration of Y2O3 embedded in the PEO coatings on Zr-4 alloy to obtain the best corrosion resistance. Nanoparticles Y2O3 was suspended in the PEO electrolyte at a concentration of 2, 3 and 4 g l−1. The particles were successfully embedded in the PEO coating composed of ZrO2–SiO2. The electrochemical test in an aqueous solution and oxidation test at 600 °C revealed a consistent result that the best corrosion resistance was obtained in the coating formed in the 3 g l−1 Y2O3-containing electrolyte. At the corresponding optimum concentration, the coating contained high SiO2 and tetragonal (t) ZrO2 phase, which potentially formed a stable solid solution ZrO2–SiO2. The improved coating stability enhanced the corrosion resistance during both aqueous solution and high temperature exposure.
Enhancing the electrochemical performance of supercapacitor electrodes using as-synthesized CuO and MOF-derived CuO nanostructures
Authors: Noor Umar , Sherin P K Risla , Sharif Ammara , Ahmed Toheed , Rahman Mehboob Ur
Published: August 2024

Metal organic frameworks (MOF’s) have gained considerable attention in the field of energy storage and supercapacitors applications. Herein, we synthesized copper oxide (CuO) through the precipitation method and concurrently derived from the solvothermal prepared copper-benzene dicarboxylate (Cu-BDC) by calcination. The integration of MOF-derived nanostructures with traditional CuO to form a hybrid electrode material, has not been extensively explored. The synthesized materials were characterized using x-ray Diffractometry, FTIR, XPS, Brunauer, Emmett, and Teller and morphological analysis was conducted using scanning electron microscopy (SEM), and high-resolution transmission electron microscopy (HRTEM) affirming the composite’s nature. Electrochemical impedance spectroscopy, galvanostatic charge–discharge, and cyclic voltammetry were used to evaluate the electrochemical properties of electrode material. With a specific capacitance of 691 Fg−1 for CuO obtained from Cu-BDC (benzene dicarboxylic acid) and 236 Fg−1 for CuO via the precipitation method, measured at a scan rate of 5 m Vs−1 in 6 M KOH was found to be the optimal performance solution for the electrode material. The mesoporous structures are crucial for their absorption ability and improved ion transport, resulting in optimized electrochemical performance. Finally, we demonstrate significant improvements in specific capacitance and cycling stability compared to pure CuO-based electrodes, highlighting the potential of this composite structure for advanced supercapacitor applications.
Algorithm prediction of single particle irradiation effect based on novel TFETs
Authors: Chong Chen , Liu Hongxia , Wang Shulong , Wang Zexi
Published: August 2024

In order to predict the single particle irradiation of tunnel field effect transistor (TFET) devices, a deep learning algorithm network model was built to predict the key characterization parameters of the single particle transient. Computer aided design (TCAD) technique is used to study the influence of single particle effect on the novel stacked source trench gate TFET device. The results show that with the increase of drain voltage, incident width of heavy ions (less than 0.04 μm), and linear energy transfer, the drain transient current and collected charge also increase. The prediction results of deep learning algorithm show that the relative error percentage of drain current pulse peak (I
DMAX) and collected charge (Q
c) is less than 10%, and the relative error percentage of most predicted values is less than 1%. Comparison experiments with five traditional machine learning methods (support vector machine, decision tree, K-nearest algorithm, ridge regression, linear regression) show that the deep learning algorithm has the best performance and has the smallest average error percentage. This data-driven deep learning algorithm model not only enables researchers who are not familiar with semiconductor devices to quickly obtain the transient data of a single particle under any conditions; at the same time, it can be applied to digital circuit design as a data-driven device model reflecting the reliability of single particle transient. The application of deep learning in the field of device irradiation prediction has a highly promising prospect in the future.
Broadband THz metasurface bandpass filter/antireflection coating based on metalized Si cylindrical rings
Authors: Simonyan Karen , Gharagulyan Hermine , Parsamyan Henrik , Khachatryan Ashot , Yeranosyan Mkrtich
Published: August 2024

The operation of the metasurface based on silicon cylindrical rings coated by a gold as a terahertz (THz) bandpass filter/antireflection structure is studied. The decrease in the reflectance is conditioned by the destructive interference of electromagnetic waves reflected from structural layers of the metasurface. An efficient antireflection band with the reflectance below 10% is formed in the frequency spectrum of 0.71–0.92 THz with a relative bandwidth of 26%. It is shown that the operating spectrum of the suggested metasurface can be varied by changing the total radius of cylindrical rings, whereas the filter’s performance is rather insensitive to the variations in cylinder height and inner radius. The dependence of the antireflection band on the polarization and incidence angle of the THz waves is also analyzed. The antireflection band is sensitive to changes in the surrounding medium, hence enabling control of the transmittance band by exploiting refractive-index-changing materials.
Performance enhancements of HTS power cables by minimizing the electric field enhancements for electric transport applications
Authors: Mullings Alexia , Mensah Paul , Das Arup K , Guvvala Nagaraju , Kim Chul H , Pamidi Sastry V , Cheetham Peter
Published: August 2024

Design innovations to manage the electric field enhancements and successful use of cryogenic epoxy EP37 as electrical insulation for high temperature superconducting (HTS) cables for electric aircraft applications are reported. Detailed finite element analysis (FEA) of the electric field distribution shows that the highest electric field is at the interface of the ground and electrical insulation layers. The FEA led to the design, fabrication, and experimental characterization of four model cables with stress cones and a direct bond of the ground and insulation layers. Enhanced partial discharge inception voltage (PDIV) was achieved in the model cables by minimizing the electric field enhancements at the ground layer interface. Using a helium gas mixture with 4 mol% H2, with higher intrinsic dielectric strength than pure helium, further enhanced the PDIV. The results warrant further studies on long HTS cables with EP37 as electrical insulation with a direct bond between the insulation and ground layers.
Screening-current-induced mechanical damage and critical current degradation in epoxy-impregnated REBCO insert coils
Authors: Liu Donghui , Wei Wanbo , Tang Yunkai , Li Dongke
Published: August 2024

In recent years, there has been growing concern about the mechanical deformation induced by the screening currents in high-field high-temperature superconducting (HTS) magnets. Screening-current-induced mechanical damage and critical current degradation have emerged as significant issues in the design and operation of HTS magnets. Currently, it is a challenging topic to consider both the nonlinear E–J power-law relationship of the REBa2Cu3O7−x
(REBCO) coated conductors (CCs) and the nonlinear interface-damaged constitutive relationship in the numerical simulation. This paper presents an electro-mechanical model combining T–A formulation with the cohesive zone model for an epoxy-impregnated REBCO insert coil, taking into account the mechanical damage dependence of the critical current of REBCO CCs. The model is validated with experimental data. Additionally, numerical results indicate that delamination and current-carrying degradation in the coil are caused by the large electromagnetic force generated by the screening current during the high-field magnetization process. The effects of screening currents on the electromagnetic and mechanical properties of the coils exhibit a significant difference between scenarios with and without consideration of the damage-dependent critical current of REBCO CCs. The underlying mechanisms leading to edge and internal damage of the REBCO CC in the coil are clarified by different failure modes. Simulations neglecting the degradation of the critical current can overestimate the stress, strain, and damage zone growth of the coil, while underestimating the current-carrying deterioration in the high field. Furthermore, a detailed analysis is conducted on the screening-current-induced mechanical damage and critical current degradation under different background fields. Finally, the influences of the structural parameters, bobbin, overband and geometric position on the delamination damage and current-carrying degradation of the coil are further investigated. This work could provide theoretical references for the design and analysis of high-field HTS insert magnets.