bluuebunny/crossref_metadata_2025 huggingface dataset:
Exploring the electrochemical properties and lithium insertion mechanisms in akaganeite (β-FeOOH) – a combined DFT/experimental study
Authors: Gonçalves Paulo Roberto Garcês , De Abreu Heitor Avelino , Montoro Luciano Andrey , Silva Gabriela Cordeiro , de Mello Ferreira Angela , Duarte Hélio Anderson
Published: November 2024

Unveiling the unique charge/discharge characteristics of akaganeite offers valuable insights into electron transfer mechanisms through experimental and DFT calculations.
Insights into Ni3TeO6 calcination via in situ synchrotron X-ray diffraction
Authors: Wang Shubo , Fernández-Catalá Javier , Shu Qifeng , Huttula Marko , Cao Wei , Singh Harishchandra
Published: November 2024

This study reveals the sequence of reactions occuring during Ni3TeO6 calicination from hydrothermal precursor.
Accelerating the reaction kinetics of Ni1−xO/Ni(OH)2/NF by defect engineering for urea-assisted water splitting
Authors: Rui Yuan , Li Zong , Wang Miaohui , Liu Yunxia , Lin Haiping , Huang Peipei , Li Qing
Published: November 2024

The reaction kinetics of Ni1-xO/Ni(OH)2/NF are accelerated through a defect engineering strategy by combining Zn doping and acid etching, leading to improved intrinsic activities for UOR.
A methodology for estimating indoor sources contributing to PM2.5
Authors: Nourani Shiva , Villalobos Ana María , Jorquera Héctor
Published: November 2024

Exposure to indoor PM2.5 originating from indoor sources is relevant, and PM2.5 chemical speciation data is necessary to estimate this exposure. This work proposes a new approach to quantify such exposure.
Improved microbial water quality and ozone performance following coagulation: implications for carbon based advanced treatment for potable reuse
Authors: Morrison Christina M. , Atkinson Ariel J. , Gerrity Daniel , Wert Eric C.
Published: November 2024

Coagulation/flocculation of secondary effluent with FeCl3 (1) removed MS2 bacteriophage and bacterial endospores up to 2–3 LRVs, (2) removed rapid surrogates at levels correlative with microbial removal, and (3) improved downstream O3 performance.
A single-stage purification method for the precise determination of zirconium isotopic composition in geological samples by double spike MC-ICP-MS
Authors: Feng Lanping , Wang Chen , Han Yan , Zhang Wen , Guo Jing-Liang , Zhou Lian , Hu Zhaochu
Published: November 2024

A simple, fast and efficient column separation method for extracting Zr from geological sample matrices using DGA resin.
Antibacterial activity of the structurally novel C-2 amine-substituted analogues based on quinoxaline
Authors: Liu Yuting , Yang Pengju , Zhou Yunyun , Zhou Zhiwen
Published: November 2024

In the current study, we have designed and prepared a series of quinoxaline-based compounds, which were derived from o-phenylenediamine.
Development of xanthan gum-based solid desiccants for the extraction of water vapors from humid air
Authors: Mittal Hemant , Alili Ali Al , Alhassan Saeed M. , Malek Naved I. , Islam Md. Didarul
Published: November 2024

A xanthan gum-acrylamide desiccant with interconnected capillary channels was prepared and showed 1.38 g g−1 water adsorption at 90% RH and 25 °C, retaining 70% capacity over 20 cycles, proving its effectiveness as a salt-free desiccant.
Synergistic color-changing and conductive photonic cellulose nanocrystal patches for sweat sensing with biodegradability and biocompatibility
Authors: Qian Yi , Wang Hao , Qu Zhen , Li Qiongya , Wang Dongdong , Yang Xindi , Qin Haijuan , Wei Haijie , Zhang Fusheng , Qing Guangyan
Published: November 2024

We designed and prepared an optical and electrical dual-signal sweat sensing patch with breathability, biocompatibility, and biodegradability, by using the strong hydrogen-bond interaction between PA and the CNC/PVA network.
Optimized nano-scaled drain- and gate-engineered Schottky barrier MOSFET with improved ambipolarity and RF characteristics
Authors: Bashir Faisal , Alzahrani Ali S. , Zahoor Furqan
Published: November 2024

GDE-SB-MOSFET device schematics, profile, gate length scaling and transfer characteristics.
Synthesis of poly(hexachlorocyclotriphosphazene-co-phenolphthalein) microspheres with negative charges for the selective removal of cationic dyes
Authors: Wang Minghuan , Song Yunfei , Xu Zhiqiang , Wang Jiying , Zhang Hekai , Chen Fang , Chang Yaqin , Wei Peng , Yin Li , Fu Jianwei
Published: November 2024

Polyphosphazene microspheres were synthesized with phenolphthalein, exhibiting exceptional adsorption capacity for cationic dyes due to the strong electrostatic attraction between the negatively charged microspheres and positively charged dyes.
Effect of fluorine substituents in 4-(1-benzyl-1H-benzo[d]imidazol-2-yl)thiazole for the study of antiparasitic treatment of cysticercosis on a Taenia crassiceps model
Authors: Rodríguez-Mora Monserrath I. , Colorado-Peralta Raúl , Reyes-Márquez Viviana , García-Eleno Marco A. , Cuevas-Yáñez Erick , Parra-Unda Jesús R. , Landa Abraham , Morales-Morales David
Published: November 2024

Fluorinated N-benzylated thiabendazoles were synthesized, fully characterized and their parasitotoxic activity explored against unhatched Taenia crassiceps cysticerci, their biological activity being enhanced by increasing the fluorine content.
A novel extra-broadband visible-emitting garnet phosphor for efficient single-component pc-WLEDs
Authors: Chen Qianyi , Lun Zhenjie , Chen Dongdan , Sun Yongsheng , Xiong Puxian , Li Siyun , Xu Shanhui , Yang Zhongmin
Published: November 2024

A defect engineering strategy mediated by the structural cationic substitution is proposed and experimentally demonstrated for ultra-broadband emission in a garnet Y3Sc2Al3O12:B3+ phosphor.
A moss-like CoB/CeO2 heterojunction as an efficient electrocatalyst for the oxygen evolution reaction under alkaline conditions
Authors: Fang Weijie , Liu Chaofan , Wu Jiang , Fan Weikai , Chen Le , Fu Zaiguo , Peng Lin , He Ping , Lin Jia , Chen Zhongwei
Published: November 2024

The moss-like amorphous CoB/crystalline CeO2 heterojunction nanosheets synthesized in this study have excellent OER activity and stability.
Flexible keratin hydrogels obtained by a reductive method
Authors: Peralta Ramos María Luz , Rivas-Rojas Patricia , Ascolani Hugo , Cavallo Margherita , Bonino Francesca , Fernandez de Luis Roberto , Guerbi María Ximena , Michelini Flabia , Bernal Celina , Lázaro-Martínez Juan Manuel , Copello Guillermo
Published: November 2024

Keratin derived materials are still underexploited due to the little understanding of their chemical versatility.
Study on the sorption and desorption behavior of La3+ and Bi3+ by bis(2-ethylhexyl)phosphate modified activated carbon
Authors: Zhu Hongshan , Heinitz Stephan , Binnemans Koen , Mullens Steven , Cardinaels Thomas
Published: November 2024

The separation of 213Bi from its parent radionuclide 225Ac via radionuclide generators has proven to be a challenge due to the limited performance of the current sorbents.
Exploration of lignin-binding synthetic polymers with pendant hydrophobic amino acids
Authors: Tanaka Tomonari , Hinohara Rika , Carias Duron Oscar Abraham , Aso Yuji , Kobayashi Naoko , Saito Kaori , Watanabe Takashi
Published: November 2024

Polymers bearing hydrophobic amino acid moieties were synthesized, and their binding affinities with wood lignin were investigated. The polymers bearing tryptophan and phenylalanine moieties were observed to exhibit high binding affinity.
MOF-derived CeO2 catalysts with Pr doping: engineering oxygen vacancies for improved CO2 conversion to dimethyl carbonate
Authors: So Jungseob , Jeong Min Hye , Yun Jungwon , An Byeong-Seon , Kim Seung-ik , Kim Geun-yeong , Kim Hyun-Tak , Chang Tae Sun , Lee Jin Hee , Heo Iljeong , An Jinjoo , You Young-Woo , Kim Minkyu , Kim Young Jin
Published: November 2024

Pr-doped CeO2 from MOF templates exhibits enhanced catalytic performance for dimethyl carbonate synthesis from CO2 and methanol, driven by increased oxygen vacancies and improved acidic/basic properties.
Ultraviolet-blocking polymers and composites: recent advances and future perspectives
Authors: Zhang Huan , Cheng Xue , Liu Cuiping , Liu Zejun , Liu Lan , Feng Can , Ju Jie , Yao Xi
Published: November 2024

This review summarizes recent innovations in strategies and mechanisms for fabricating UV-blocking polymers and composites.
A multi-frequency, multi-epoch radio continuum study of the Arches cluster with the Very Large Array
Authors: Cano-González M. , Schödel R. , Alberdi A. , Moldón J. , Pérez-Torres M. , Najarro F. , Gallego-Calvente A. T.
Published: November 2024

Context. The Arches cluster, one of the most massive clusters in the Milky Way, is located about 30 pc in projection from the central massive black hole Sagittarius A* at a distance of ≈8 kpc from Earth. With its high mass, young age, and location in the Galaxy’s most extreme star forming environment, the Arches is an extraordinary laboratory for studying massive stars and clusters.

Aims. Our objective is to improve our knowledge of the properties of massive stars and the Arches cluster through high-angular-resolution radio continuum studies.

Methods. We observed the Arches cluster with the Karl G. Jansky Very Large Array in the C- and X-bands (central frequencies of 6 and 10 GHz respectively) in two epochs at C-band and five epochs at X-band throughout 2016, 2018, and 2022, covering time spans ranging from 22 days to 6 years. We used the A-configuration to achieve the highest possible angular resolution and cross-matched the detected point-sources with stars detected in the infrared, using proper motion catalogues to ensure cluster membership.

Results. We report the most extensive radio point-source catalogue of the cluster to date, with a total of 25 radio detections (7 more than the most recent study). We also created the deepest (2.5 μJy in X-band) images of the cluster so far in the 4 to 12 GHz frequency range. Most of our stellar radio sources (12 out of 18) show a positive spectral index, indicating that the dominant emission process is free-free thermal radiation, which probably originates from stellar winds. We find that radio variability is more frequent than what was inferred from previous observations, and affects up to 60% of the sources associated with bright stellar counterparts, with two of them, F18 and F26, showing extreme flux variability. We propose four of our detections (F6, F18, F19, and F26) as primary candidates for colliding-wind binaries (CWBs) based on their consistent flat-to-negative spectral index. We classify F7, F9, F12, F14, and F55 as CWB binary candidates based on their high flux and/or spectral index variability, and X-ray counterparts. Thus, we infer a 14/23 ≈ 61% multiplicity fraction for the radio stars of the Arches cluster when combining our findings with recent infrared radial velocity studies.
Exciting Fossil Discoveries Shed Light on the Origin and Evolution of Fishes and Reptiles
Authors: Wang Min
Published: November 2024

Over the last decade, numerous important vertebrate fossils have been discovered by scientists from the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) of the Chinese Academy of Sciences (CAS), which have significantly enriched understanding about the origin and early evolution of fish, amphibians, and reptiles. Particularly, researches about the origin of jawed vertebrates and origin of birds have systematically revised previous thoughts. These studies also demonstrate the globally leading role played by IVPP research teams in this field.
Quality approach towards ISO/IEC 17025 accreditation at the center of analysis and characterization of Marrakesh Cadi Ayyad University: metrology stakes
Authors: Outaki Meriem , Benhaida Sara , Belaqziz Majdouline , Outzourhit Abdelkader , Calchera Gilles , Thévenon Marie-France , Martin Luc , Charki Abdérafi , Ajana Hamid
Published: November 2024

In the context of the European Tempus project “Quality in Higher Agricultural Education in the Mediterranean (QESAMED)”, Analysis and Characterization Center of Cadi Ayyad University has committed to implement a quality approach according to the ISO/IEC 17025 standard. The first objective was to accredit the testing carried out in the microbiology laboratory in response to strong demand from the food industry in the Marrakesh region. The process began with an initial assessment of the center activities to identify the main gaps from ISO/IEC 17025. The range of laboratory and standard testing to be accredited were determined and an appropriate action plan was established. After that, a staff training was programmed to improve their skills in relation to this standard and metrology concepts. Implementation of the metrology function is one of the key steps for the deployment of the continuous improvement process. This function guarantees the traceability of measurements and the reliability of microbiological testing results. Several actions have been carried out, including: (i) identification of critical quantities and associated metrological requirements, (ii) checking of the metrological consistency of equipment through the calculation of the capability coefficient. The management of equipment requires several steps, from receipt of the equipment to its decommissioning or reform: (i) identification of the equipment, (ii) creation of equipment files, (iii) performance of calibration, verification, and maintenance operations. Ultimately, the definition of a strategy ensuring metrological traceability will optimize management costs by taking into account the structural constraints linked to the organization of metrology on a national scale.
Effect of types of calcium-containing alloy on non-metallic inclusions in high-Al steel
Authors: Zhao Jixuan , Zheng Zhihao , Zhu Hangyu , Wang Lanqing , Guo Shuai
Published: November 2024

The influence of different calcium-containing alloys on inclusions in high-Al steel is investigated in the current study. The effects of SiCa, AlCa20, AlCa75 and FeSi alloys on the modification of solid inclusions in molten steel are compared, and the mechanism of inclusion evolution is revealed based on the non-uniform distribution of elements and the lattice mismatch between the inclusion particles. The results show that the Ca yield of FeSi alloy is 26%, which is significantly higher than that of other alloys (<5%). In addition, the calcium treatment by FeSi alloy causes less aspiration of molten steel, which is conducive to avoiding the increase of AlN in high-Al steel. After calcium treatment, the primary Al2O3 particles in steel are transformed into CaO-Al2O3-CaS and CaO-Al2O3-MgO complex inclusions, while AlN can only be precipitated in the form of a single particle, or precipitated from the transformed CaO · 2Al2O3 oxide. In general, FeSi alloy has the best effect on the modification of Al2O3 inclusions, which can maximize the transformation of solid particles into liquid inclusions in steel liquid without introducing too much impurities.
A hybrid PCA-SOA-BP approach for predicting converter endpoint temperature in steelmaking
Authors: Wang Zhiwen , Fan Fuhua , Xu Weli , Bao Yanping , Zhao Lihua
Published: November 2024

Accurately controlling the temperature of the converter end is a crucial element of the steelmaking process. To enhance the accuracy of predicting the converter end temperature, we propose a hybrid model that utilizes principal component analysis (PCA) and snake optimization algorithm (SOA) in conjunction with a backpropagation algorithm (BP) neural network. The 16 parameters for smelting in converter steelmaking were reduced using principal component analysis to remove shared features. The nine principal components derived from this analysis were then used as input variables for an optimized BP neural network. An optimization algorithm was then employed to refine the initialized weights and thresholds of the BP neural network. The impact of neuron node quantity in the hidden layer on the BP neural network was examined. Results show that the ideal BP neural network is achieved with 19 neuron nodes in the hidden layer. Compared with ordinary BP neural network, PCA-BP neural network and SOA-BP neural network, the model proposed in this study can predict the end temperature of converter most accurately. In the temperature error range of ±10 °C and ±15 °C, the prediction accuracy of the model is 93% and 96%, respectively. Meanwhile, the model has been effectively applied in the industrial production of a steel plant in China. The results show that the prediction results of the model are in good agreement with the actual production data in the field. This accurate prediction can optimize the field operation process and realize the stable control of product quality.
Enhancing real-world studies with artificial intelligence: addressing ethical and quality challenges
Authors: Li Ji-Bin , Qian Chao-Nan
Published: November 2024

Real-world studies have been widely conducted in medical research to generate evidence for improving clinical decision-making. However, several issues arise when conducting prospective real-world studies, including a lack of informed consent, increased patient burden, potential decision bias, and the risk of sales promotion. These challenges can compromise real-world studies’ integrity, ethics, and reliability. This editorial explores how integrating artificial intelligence technologies can help address the challenges associated with conducting prospective real-world studies.
Lactate Dehydrogenase Levels after Aortic Valve Replacement: What Do They Tell Us?
Authors: Rodriguez Cetina Biefer Hector , Dzemali Omer , Rings Laura , Mavrova-Risteska Loreta , Haeussler Achim , Ntinopoulos Vasileios , Tanadini Matteo
Published: November 2024

Introduction Lactate dehydrogenase (LDH) is a standard postoperative marker for hemolysis in the presence of paravalvular leakage (PVL) after replacement of the aortic valve (AVR). LDH is elevated in certain valves by a fluttering phenomenon. Previous studies suggested a correlation between microparticles (MPs) and LDH elevation after AVR. Thus, we analyze the postoperative relevance of LDH after AVR with transapical transcatheter aortic valves (TA-TAVs) or rapid deployment valves (RDVs).

Methods We retrospectively analyzed the data from patients who received an AVR with the RDV and TA-TAV groups between 2015 and 2018. We compared PVL and LDH levels before and after surgery, transvalvular gradients, heart block that required pacemaker implantation, and 30-day mortality.

Results In total, 138 consecutive patients were selected for the study: 79 patients in the RDV group (37 Sorin Perceval valve, 42 Edwards Intuity valve) and 59 in the TA-TAV group (Edwards Sapien valve). TA-TAV group was older (median 10 years) and had a higher incidence of PVL (odds ratio 11, 95% confidence interval [CI] 2.5–73.2, p = 0.04)). Interestingly, the TA-TAV group showed lower levels of LDH despite higher rates of PVL. Of note, the Perceval valve trended toward higher LDH values. Additionally, the RDV group showed an increased arrhythmia profile (p = 0.0041); however, the results show lower incidence in pacemaker implantation (95% CI 0.05–1.65, p = 0.635). The 30-day mortality was similar between groups.

Conclusion Our data do not support the association between hemolysis and PVL despite elevated LDH in suture-free valves. Our results suggest that LDH could be a marker of extreme heart muscle output or fluttering phenomenon and not a marker of hemolysis after sutureless AVR.
The IV-characteristic of the long josephson junction at the zero-field step
Authors: Grib Alexander , Chykina Olena
Published: November 2024

The influence of Josephson vortices on the formation of the first zero-field step is investigated theoretically by two methods. The first method is based on the numerical solution of the dynamical equations. The spatial distribution of the critical currents along the junction has a small irregularity of 10–3% at an arbitrary location, which allows the formation of zero-field steps in the IV-characteristic. The periodic motion of Josephson vortices in the junction is studied in detail using the first method. The IV-curve and the Josephson penetration depths of the magnetic field for different voltage values are determined. According to the second method, described earlier in the literature, the IV-curve can be found analytically from the equality of the input power and the dissipation rate in the junction, and the zero-field step is formed solely by the movement of the Josephson vortices. The comparison of the zero-field steps found by the two methods mentioned above showed that both methods give almost identical results, except for the top of the step, where the second method gives larger values. Thus, it is proven that the first zero-field step in the IV-curve of the long junction is formed by the motion of Josephson vortices.
Superconducting materials for fusion reactors: A brief review
Authors: Goulatis Ioannis , Daskalopulu Aspassia , Solovjov Andrei L. , Vovk Ruslan V. , Chroneos Alexander
Published: November 2024

The introduction of high-temperature superconductors and, in particular, cuprate oxides such as REBa2Cu3O7–δ (where RE = Y, lanthanides) has led to developments in applied physics and technology. These materials have high technological potential for more economical, smaller magnetically confined fusion reactors due to the high field strengths. The introduction of high-temperature superconductors in the form of tapes in fusion reactors is not technologically trivial as these reactors eject high-energy neutrons that can damage the material and hinder its operation. In the present review, we consider the technological issues that need to be addressed for the implementation of REBa2Cu3O7–δ in fusion reactors.
Wicking pumps for microfluidics
Authors: Aghajanloo Behrouz , Losereewanich Wil , Pastras Christopher J. , Inglis David W.
Published: November 2024

This review describes mechanisms for pulling fluids through microfluidic devices using hydrophilic structures at the downstream end of the device. These pumps enable microfluidic devices to get out of the lab and become point-of-care devices that can be used without external pumps. We briefly summarize prior related reviews on capillary, pumpless, and passively driven microfluidics then provide insights into the fundamental physics of wicking pumps. No prior reviews have focused on wicking pumps for microfluidics. Recent progress is divided into four categories: porous material pumps, hydrogel pumps, and 2.5D- and 3D-microfabricated pumps. We conclude with a discussion of challenges and opportunities in the field, which include achieving constant flow rate, priming issues, and integration of pumps with devices.
Physical mechanisms of femtosecond laser induced refractive index change in direct-written mid-infrared fiber Bragg gratings
Authors: Fernandez T. Toney , Xu Luyi , Gross Simon , Bharathan Gayathri , Ams Martin , Privat Karen , Withford Michael J. , Fuerbach Alex
Published: November 2024

Femtosecond laser inscription of fluoride Fiber Bragg Gratings (FBGs) has enabled the realization of all-fiber laser sources at mid-infrared wavelengths. However, many fundamental aspects of the fabrication process remain unknown, which hinders further development. In this paper, we for the first time reveal the physical mechanisms that underpin the laser-induced permanent refractive index change in the periodic grating elements that constitute an FBG. Quadriwave lateral shearing interferometry and micro-reflectivity measurements are introduced as techniques for the full characterization of the refractive index change profile of the grating structure. The fundamental processes that eventually result in a permanent index change were found to differ significantly between the chemically closely related fluoroindate and fluorozirconate glass families. In fluoroindate fibers, the index change can almost entirely be attributed to elemental migration, whereas in fluorozirconate fibers the involved processes are more intricate and include the selective migration of fluorine ions as well as the formation of F-centers, more specifically unpaired electrons trapped in anion vacancies. In addition, in fluorozirconate fibers, the formation of dynamic stress regions in-between the grating planes was observed, more specifically a build-up of higher stress in areas adjacent to positive index-change regions and of lower stress in areas adjacent to negative index-change regions, which for the first time explains the unusual annealing behavior of mid-IR FBGs.
Ion temperature gradient mode mitigation by energetic particles, mediated by forced-driven zonal flows
Authors: Sama J. N. , Biancalani A. , Bottino A. , Del Sarto D. , Dumont R. J. , Di Giannatale G. , Ghizzo A. , Hayward-Schneider T. , Lauber Ph. , McMillan B. , Mishchenko A. , Muruggapan M. , Rettino B. , Rofman B. , Vannini F. , Villard L. , Wang X.
Published: November 2024

In this work, we use the global electromagnetic and electrostatic gyro kinetic approaches to investigate the effects of zonal flows forced-driven by Alfvén modes due to their excitation by energetic particles on the dynamics of ITG (ion temperature gradient) instabilities. The equilibrium of the 92416 JET tokamak shot is considered. The linear, nonlinear Alfvén modes, and the zonal flow dynamics are investigated, and their respective radial structures and saturation levels are reported. ITG dynamics in the presence of the zonal flows excited by these Alfvén modes are also investigated. The zonal flows forced-driven by Alfvén modes can significantly impact the ITG dynamics. A zonal flow amplitude scan reveals the existence of an inverse relation between the zonal flow amplitude and the ITG growth rate. These results indicate that forced-driven zonal flows can be an important indirect part of turbulence mitigation due to the injection of energetic particles.
Multimodality in systems driven by Ornstein–Uhlenbeck noise
Authors: Dybiec Bartłomiej
Published: November 2024

The presence of noise in nonlinear dynamical systems can significantly change their properties. Here, we study the properties of a noise perturbed motion in a single-well potential of |x|n (n>0) type. We explore under what conditions the action of the Ornstein–Uhlenbeck noise induces bimodality of stationary states in static, single-well, power-law potentials. In particular, we inspect the transition from unimodality (n⩽2) to bimodality (n>2). Results of numerical simulations are compared with estimates obtained from the unified colored-noise approximation. Furthermore, we explore the role of a harmonic addition to the general single-well power-law potentials showing its constructive or destructive role.
Passive time-varying waveform-selective metasurfaces for attainment of magnetic property control
Authors: Kunitomo Yuki , Takimoto Kairi , Vellucci Stefano , Monti Alessio , Barbuto Mirko , Toscano Alessandro , Bilotti Filiberto , Ramachandran Tayaallen , Njogu Peter Muthondio , Dang Phuc Toan , Wakatsuchi Hiroki
Published: November 2024

We present circuit-loaded metasurfaces that behave differently in a passive manner even at the same frequency in accordance with the incoming waveform, specifically its pulse width. Importantly, the time-varying waveform-selective metasurfaces reported thus far were mostly able to change their electric properties but not their magnetic properties; this severely limited the design range of their corresponding wave impedances and refractive indices and thus hindered the development of potential applications in antennas, sensors, imagers, signal processing, and wireless communications. In this study, passive time-varying waveform-selective metasurfaces were found to attain magnetic property control by introducing an additional circuit-loaded layer that generated an artificial magnetic dipole moment; this magnetic moment only occurred during the designed pulse duration in the time domain. Our proposed concept and structures were validated numerically and experimentally; thus, our results could be used to address electromagnetic and related issues sharing the same frequency component via the variation of the pulse width as an additional degree of freedom.
A comprehensive molecular dynamics simulation of plastic and liquid succinonitrile: Structural, dynamic, and dielectric properties
Authors: Canales Manel , Skarmoutsos Ioannis , Guardia Elvira
Published: November 2024

Molecular dynamics simulations at constant temperature and pressure were carried out to investigate the structural, dynamical, and dielectric properties of succinonitrile in its plastic and liquid phases at several thermodynamic states. A six-site united atom model was employed with a force field incorporating an intramolecular torsional term that accurately describes gauche and trans conformers. Analysis of the radial distribution function showed that succinonitrile adopts a body-centered cubic arrangement below its melting point, transitioning to a less ordered state in the liquid phase. In addition, examination of alignments between methylene bonds and the diagonals of the simulating cubic box revealed pronounced directional preferences in the plastic phase. The study of conformational states suggested that succinonitrile molecules predominantly adopt gauche conformations, which exhibit longer lifetimes than trans conformers. Spectral density analysis highlighted distinct peaks for different molecular sites, revealing significant differences between gauche and trans conformers. The correlation functions of bending and torsional angles, as well as vectors joining different atoms, illustrated a sensitivity to internal motions, which were notably faster for trans conformers. Differences in decay rates between trans and gauche conformers underscored the influence of gauche–trans transitions. The static dielectric constant, which has been derived from the total dipole moment, was primarily influenced by the contribution of the gauche conformers. In addition, the distance-dependent Kirkwood factor was computed, revealing antiparallel alignment at short distances. Finally, the dielectric relaxation time and the static dielectric constant values were compared with experimental data.
Efficient coupling between photonic waveguides and III-nitride quantum emitters in the UV-visible spectral range
Authors: Jawad Ul Islam Md. , Kundu Mrinmoy , Anand Nirmal , Sadaf Sharif Md. , Zunaid Baten Md
Published: November 2024

In this study, we establish comprehensive design guidelines to maximize single-mode transmission by efficient coupling between a III-nitride quantum-dot-in-nanowire light emitter and a photonic waveguide in the ultraviolet-visible (UV-Vis) spectral range. Considering feasible epitaxial growth, deposition, and fabrication techniques, this study performs detailed electromagnetic simulations to identify the design limits of viable material systems suitable for monolithic integration of vertical III-nitride nanowires on standard ridge waveguides. We show that unlike systems operating in the near-infrared wavelengths, light coupling and transmission in the UV-Vis range are significantly constrained by substrate leakage and backreflection. Such constraints arise from refractive index contrast of the associated waveguide and substrate materials suitable for epitaxial growth and device fabrication. For optimized dimensions of the nanowire and waveguide structures, the maximum unimodal transmission for practical monolithic systems is ∼14% within the wavelength range of 300–500 nm. The theoretical transmission limit of the monolithic system is shown to be 35% with a substrate of unity refractive index. It has been shown that the best strategy of maximizing coupling between the emission mode of the vertical nanowire and the propagation mode of the planar ridge waveguide is to increase the refractive index contrast between the waveguide and substrate material. Based on these key findings, we propose heterogeneously integrated hybrid structures, which significantly exceeds the unimodal transmission limits of standard monolithic systems attainable with III-nitride material systems in the UV-Vis wavelengths.
Coupling impacts of end effects and rotation on the three-dimensional flow around a rapidly rotating circular cylinder with two flat ends
Authors: Liu Qiliang , Gong Shuguang , Lu Haishan , Tang Fang , Liang Zhiwei
Published: November 2024

This paper studies the interactions of rotation and end effects and its effect on the flow around a rapidly rotating circular cylinder with two flat ends, using the large eddy simulation method. At a Reynolds number of 4.6×104, four aspect ratios are examined across spin ratios in the range of 0–7 with an increment of 0.5. The obtained results show that, when the spin ratio increases, the mean drag coefficient first decreases, then rapidly increases, and finally gradually decreases or becomes stable. Two critical spin ratios are identified. The mean lift coefficient first rapidly increases and then decreases slightly or stabilizes, with one critical spin ratio observed. When the aspect ratio increases, the three critical values shift to higher spin ratios. Within the specified parameter ranges, eight distinct vortex shedding modes are identified, evolving with changes in aspect ratio and spin ratio. These modes mainly include various combinations of hairpin, tip, streamwise elongated, and ring-shaped vortices. The results demonstrate that, when the aspect ratio decreases or the spin ratio increases, the weak influence region of end effects on the sectional aerodynamic coefficients diminishes and even completely disappears, while the strong influence region expands. More precisely, for the ranges of specified parameters, when the aspect ratio becomes greater than 10, the influence range of end effects is mainly controlled by the spin ratio.
3D manipulation of small multicellular organisms in soft microtubes
Authors: Khobdabayev Maksat , Hayek Thea , Alnajjar Salama , Alkasaji Layan , Orozaliev Ajymurat , Song Yong-Ak
Published: November 2024

Small multicellular organisms, such as C. elegans and zebrafish larvae, are essential models in biological research, but their 3D manipulation poses challenges due to their small size. Manual positioning is labor-intensive and imprecise. To address this, we developed a soft PDMS microtube that can be gently stretched and released, immobilizing organisms without anesthetization and damage. This tube enables easy rotation and adjustment of orientation, facilitating comprehensive imaging. Functionality testing showed effective immobilization as well as precise imaging and microinjection. Zebrafish larvae were successfully injected with fluorescein in the hindbrain without anesthesia. This technique offers a simple, efficient, and non-damaging method for 3D manipulation and imaging of small multicellular organisms and provides a versatile tool for biological research practices.
Percolative dielectric behavior of titanium carbide MXene/cellulose nanofibrils composite films
Authors: Jurečič Vida , Lakshmanan Subramanian , Novak Nikola , Kokol Vanja , Bobnar Vid
Published: November 2024

Cellulose-based nanomaterials are fascinating renewable biosystems, yet low thermal conductivity and dielectric permittivity often limit their potential applications in flexible electronics. We report dielectric properties of composite films prepared by vacuum filtration or solvent casting method from the native (CNF) or carboxylated (TCNF) cellulose nanofibrils and high electrically and thermally conductive 2D titanium carbide (Ti3C2Tx) MXenes. Measurements over broad frequency and temperature ranges revealed the influence of preparation method and type of nanofibrils matrix on the overall dielectric response, as well as a notable impact of absorbed water, particularly on the cellulose’s secondary β and γ relaxations. A detailed investigation of material with the lowest amount of impurities, vacuum-filtered MXene/CNF composites, confirmed that the dielectric response follows the predictions of the percolation theory. The resulting strong enhancement of the dielectric permittivity on increasing MXene content demonstrates the potential of developed composites for applications in eco-friendly dielectric and piezoelectric devices.
Study of crystal property prediction based on dual attention mechanism and transfer learning
Authors: Xu Yongyin , Deng Wei , Zheng Jiaxin
Published: November 2024

To avoid the step of manual feature engineering when predicting crystal properties, a graph convolutional neural network based on the dual attention mechanism, named DA-CGCNN, is proposed. It fuses both the channel attention mechanism and self-attention mechanism, named the dual attention mechanism, benefiting from capturing the complex features of each atom and dependencies between atomic nodes better. It is found to have comparable or superior performance to other advanced graph neural network (GNN) models by predicting five properties of the crystal: formation energy, total energy, bandgap, Fermi energy, and density. In addition, cross-property transfer learning is conducted on the computed properties from four small-sample crystal materials. The results show better performance on transferring prediction from these four samples. The proposed model in this study significantly improves the accuracy of crystal property prediction and demonstrates excellent prediction performance by incorporating transfer learning techniques. In summary, this work is important in accelerating the prediction of crystalline material properties and the discovery and design of crystalline materials.
Propulsion performance of flapping hydrofoil by using discrete vortex method
Authors: Ren Peng , Wang Jiasong , Lin Ke , Fan Dixia
Published: November 2024

The insight to the hydrodynamics of the flapping hydrofoils can be utilized to comprehend the fluid-mechanical mechanisms for the variation of the hydrofoil's propulsion performance, and optimize the design of the bio-inspired underwater robots. This paper numerically investigates the hydrodynamic performance of a two-dimensional NACA 0012 (defined by National Advisory Committee for Aeronautics) hydrofoil undergoing combined pitching and heaving motions, based on the discrete vortex method. A novel boundary method which couples the Joukowsky transformation and the circle theorem is used to deal with the vortex elements inside the hydrofoil surface. The numerical method is validated by the experiments from the available relative cases by comparing the hydrodynamic forces and the wake patterns with the pure pitching and pure heaving hydrofoil. Via the vortex dynamics, the discussion is carried out to explain the thrust deterioration within the large Strouhal number and large pitching amplitude in the combined motion. Further, a parameter optimization study is conducted under different heaving amplitudes and pivot locations. When the heaving amplitude is 1.25c and the pivot location is at 0.45c, the propulsion efficiency of the flapping hydrofoil is found maximized. Finally, by combining the time history of hydrodynamic forces and the formation and release of the leading-edge vortex and trailing-edge vortex in the vorticity field, this paper explains the reason why the optimal efficiency is obtained.
Molecular dynamics investigation of unsupported double-shock induced micro-jet behaviors in copper containing helium bubbles
Authors: Bao Qiang , Wu Bao , Wang Xin-Xin , Sui Haonan , Geng Hua Y. , Shao Jian-Li , Sun Hai-Quan , He An-Min , Wang Pei
Published: November 2024

When exposed to irradiation environment, the formation of helium bubbles within metallic materials profoundly influences its surface damage. This study employs molecular dynamics simulations to investigate micro-jet behaviors of copper containing helium bubbles under twice shock loading with high pressures. The research underscores the pivotal role of the first shock-induced damaged morphology in dynamic responses during the secondary shock loading. In contrast to pure Cu, the presence of randomly distributed helium bubbles with larger size after the first shock disrupts symmetry along the shock direction, thereby amplifying transverse atom momentum and resulting in micro-jets with chaotic and unstable microstructures. Helium bubbles situated at peak position of the initial surface coalesce after the first shock, equivalent to deepen the surface perturbation of the subsequent shock. Conversely, bubbles located in surface grooves expand significantly after the second shock, thereby intensifying micro-jet growth. It has been shown that the ejecta mass after the secondary shock has also been increased due to the presence of helium bubbles, which is attributed to the larger bubble size compared to that of voids in pure copper. Similar conclusion has been drawn by increasing the time interval between the two shock loadings of the models, which prolongs the growth period of voids or bubbles after the first shock, thereby augmenting both defect volume and size and promoting enhanced mass accumulation and ejecta velocities. Overall, this study advances our understanding of the physical mechanisms governing near-surface damage in metal materials containing helium bubbles under the twice shock loading.
Evaluating nonmetal atom doping in two-dimensional VSe2 monolayers for hydrogen and oxygen electrocatalysis
Authors: Hassan Rabia , Ma Fei , li Yan , Hassan Rehan , Qadir Muhammad Farhan
Published: November 2024

The electrocatalytic performance of VSe2 doped with nonmetals (NMs) was studied using density functional theory, in which NM atoms (C, N, O, P, S, F, Cl, Br, and I) replaced Se or V (denoted as NM@Se or NM@V). Notably, P@V and Br@V monolayers exhibit high catalytic hydrogen evolution reaction activity with the lowest ΔGH* = 0.08 eV and −0.03 eV, respectively, surpassing Pt (ΔGH* = −0.1 eV). By applying the scaling relationship of ΔGH* of H*, which is an intermediate for each volcano, the exchange current density diagrams are established. Based on thermodynamic analysis, P@V and Br@V monolayers produce exchange currents of about −1.42 and −0.70i0/(A cm−2), respectively. The oxygen evolution reaction activity of the I@Se monolayer (ηOER = 0.95 V) is the best among all the monolayers. Among the oxygen reduction reaction catalysts, the O@Se monolayer displays high activity with a low ηORR (0.82 V), which is even better than that of binary Pt and Pd alloys (0.9–0.87 V).
Harnessing room-temperature ferroelectricity in metal oxide monolayers for advanced logic devices
Authors: Naseer Ateeb , Rafiq Musaib , Bhowmick Somnath , Agarwal Amit , Singh Chauhan Yogesh
Published: November 2024

Two-dimensional ferroelectric materials are beneficial for power-efficient memory devices and transistor applications. Here, we predict out-of-plane ferroelectricity in a new family of buckled metal oxide (MO; M: Ge, Sn, Pb) monolayers with significant spontaneous polarization. Additionally, these monolayers have a narrow valence band, which is energetically separated from the rest of the low-lying valence bands. Such a unique band structure limits the long thermal tail of the hot carriers, mitigating subthreshold thermionic leakage and allowing field-effect transistors (FETs) to function beyond the bounds imposed on conventional FETs by thermodynamics. Our quantum transport simulations reveal that the FETs based on these MO monolayers exhibit a large ON/OFF ratio with an average subthreshold swing of less than 60 mV/decade at room temperature, even for short gate lengths. Our work motivates further exploration of the MO monolayers for developing advanced, high-performance memory and logic devices.
Dissociation temperature of gas hydrates through isenthalpic–isobaric molecular dynamics simulations
Authors: Weidmann Arthur B. , Franco Luís F. M. , Sum Amadeu K. , Pessôa Filho Pedro A.
Published: November 2024

Molecular simulations are a powerful tool to understand phenomena and obtain properties of gas hydrate systems. The direct coexistence method (DCM) in the NVT or NPT ensembles, the most commonly used method to determine hydrate dissociation temperatures, can be computationally expensive due to the need for several long simulations. Through an extensive set of simulations, we report here the details of the DCM within the NPH (isobaric–isenthalpic) ensemble, which require fewer and shorter trajectories. The dissociation pressure of methane hydrates is obtained for pressures of 4, 8, 15, 30, and 50 MPa. The values are in agreement with other literature simulations and experimental data. The results are further validated with the calculation of the enthalpy of dissociation, with a value of 50 kJ/mol of methane, also in agreement with the literature. The complexity of a multiphase and multicomponent system presents challenges lacking in simpler water/ice systems. These are found to be dependent on energy conservation. The optimal set of parameters to achieve it is also reported, including a smaller time step and the use of double precision, along with an analysis of some factors that could affect the convergence of the method. Although these parameters require more computational cost, the NPH ensemble is successful in providing the dissociation temperature of gas hydrates in fewer simulations than other ensembles and with productions lasting only 500 ns.
Artificial neural network-based computational heat transfer analysis of Carreau fluid over a rotating cone
Authors: Ullah Fahim , Ashraf Muhammad Bilal
Published: November 2024

Heat transport in a dynamically rotating cone immersed in a Carreau fluid is the subject of this investigation. The fluid is non-Newtonian, admired for its characteristics, and extensively utilized in numerous industrial domains. The study investigates the interplay between buoyancy and centrifugal forces within an analytical framework. The study employs sophisticated mathematical methods, including similarity transformations, to convert governing partial differential equations into nonlinear ordinary differential equations. These equations are then solved using the shooting method, a numerical technique that solves a boundary value problem by iteratively adjusting the initial conditions until the boundary conditions are satisfied. We employ an artificial neural network algorithm with backpropagation Levenberg–Marquardt scheme to analyze the heat transfer mechanism quantitatively. In conjunction with the shooting mechanism, we will use numerical simulation with an artificial neural network algorithm, namely the backpropagation Levenberg–Marquardt scheme. The results prove the enormous influence of centrifugation and buoyancy on complex fluid dynamics and heat exchange processes. Some critical parameters that govern the convective heat transport process are the Nusselt number, the Reynolds number, the Grashof number, and the fluid and cone rotational velocities. The research validates the requirement of considering non-Newtonian complexity and viscous dissipation when investigating heat transfer dynamics and fluid flow, facilitating more accurate expectations and improved efficiency in various industrial processes.
Impact-induced energy release and damage effect of reactive materials in air and argon environments
Authors: Zhou Jie , Wang Shuai , Zhao Xufeng , Li Haijie , Pi Aiguo
Published: November 2024

To investigate the impact of energy release of reactive material on its damage effect, a modified test chamber was developed to conduct vented chamber tests and penetration tests in both air and argon environments of Al/Ti and Al/TI/W reactive projectiles. The deformation volumes obtained from the scanning results were employed to characterize the damage effect of the reactive materials on multi-spaced plate targets. Several key results include the following: Despite its lower energy density, the Al/Ti/W composite exhibits higher energy release efficiency than the Al/Ti composite. This is attributed to the lower strength of the material, causing it to fragment into finer debris upon impact, thereby facilitating easier ignition and reaction. The Al/Ti/W projectiles induce a significant deformation volume in the plates during penetration tests but exhibit a decrease in penetrative capacity. This phenomenon is attributed to the mechanical characteristics of the Al/Ti/W materials rather than the energy release upon impact. The deflagration of reactive materials during impact does not significantly enhance the structural damage of the target, at least at impact velocities below 1200 m/s.