bluuebunny/crossref_metadata_2025 huggingface dataset:
Isomeric orientation of the S atom in thiophene of benzodithiophene-4,8-dione to achieve a high-performance electrochromic polymer
Authors: Chao Pengjie , Su Qicheng , Liao Yuqing , Mo Daize , Shen Dongling , Shi Yizhong , Li Lanqing
Published: February 2025

The importance of the isomeric orientation of a thiophene ring and conjugation length in tuning the electrochromic performance of polymers, offering a promising approach for designing high-performance electrochromic materials.
Efficient and Selective Hydroboration of Alkenes Catalyzed by an Air-Stable (PPCF3P)CoI2 Precatalyst
Authors: Fitzsimmons Matthew C , Seith Maria C , Moore Curtis , Thomas Christine M.
Published: February 2025

ABSTRACT: Alkene hydroboration provides a convenient route to generate organoborane synthons and recent effforts to develop catalysts for this and many other organic transformations have involved a shift to Earth-abundant...
Synthesis of vinyl, alkyl-substituted chiral acrylates via Krische iridium complex-catalysed allylic phosphonation
Authors: Zhang Yuan-Yuan , Deng Yi , Wei Kun , Yang Yu-Rong
Published: February 2025

An enantioselective preparation of vinyl, alkyl-substituted chiral α-stereogenic acrylates is reported using two consecutive steps of Ir-catalysed allylic alkylation of aliphatic allylic acetates with phosphonates and HWE olefination.
Fabrication, characterization and electrochemical analysis of a polyvinylidene fluoride plus zeolite embedded manganese phosphate composite ion exchange membrane
Authors: Arsalan Mohd , Khan Mohd Adeel , D. Rhithuparna , Rahman Wasi Ur , Alajmi Mohamed Fahad , Hussain Afzal , Halder Gopinath
Published: February 2025

Demonstration of a polyvinylidene fluoride and zeolite nanocomposite membrane embedded with manganese phosphate (PVDF+Ze@MP) via the sol–gel method.
Electrochemically Assisted Friedlander Reaction: Highly Efficient and Sustainable Method for Quinoline Synthesis
Authors: Salehzadeh Hamid , Rostami Bigdeli Zahra , Lam Kevin
Published: February 2025

The Friedländer reaction is a well-established method for quinoline synthesis. However, it has significant limitations, including long reaction times, the use of environmentally harmful solvents and reagents, and significant waste...
3-Keto-indazole derivatives exhibiting multi-coloured phosphorescence
Authors: Moriyama Tetsuya , Kobayashi Ryota , Chiba Takayuki , Okada Shuji , Yamakado Ryohei
Published: February 2025

1H indazole derivatives with a ketoaryl groups at the 3-position were synthesized by a cyclisation reaction. All derivatives showed phosphorescence and/or double luminescence both in solution and the solid state.
Artemselenoids A−H, eight guaiane-type sesquiterpenoid dimers from Artemisia selengensis and their antihepatoma activities
Authors: Chen Rong-Kai , Li Tian-Ze , Ma Yun-Bao , Wang Yong-Cui , Chen Ji-Jun
Published: February 2025

Eight undescribed guaiane-type sesquiterpenoid dimers (GSDs), artemselenoids A−H (1−8), together with nine known GSDs (9−17), were isolated from Artemisia selengensis. Their structures and absolute configurations were determined through comprehensive spectral...
Maternal Oral Reading Expressiveness in Relation to Toddlers' Concurrent Language Skills Across a Continuum of Early Language Abilities
Authors: Zuk Jennifer , Davison Kelsey E. , Doherty Laura A. , Manning Brittany L. , Wakschlag Lauren S. , Norton Elizabeth S.
Published: February 2025

Purpose:

A rich body of evidence has illuminated the importance of caregivers' use of prosody in facilitating young children's language development. Although caregiver–child shared reading has been repeatedly linked to children's language skills, caregiver prosody during shared reading interactions (i.e., oral reading expressiveness) has been largely overlooked in research to date. Here, we investigated whether maternal oral reading expressiveness is associated with language skills among late-talking and typical-talking toddlers.

Method:

Forty mother–child dyads, with toddlers classified as either late talkers (
n
= 18) or typical talkers (
n
= 22), engaged in a shared reading interaction. Acoustic measures of oral reading expressiveness (mean fundamental frequency [
F
0], rate) were compared between mothers of late versus typical talkers. Whole-group analyses then examined oral reading expressiveness in relation to toddlers' concurrent receptive and expressive language skills across the continuum.

Results:

Between-group comparisons of mothers of late versus typical talkers revealed no group differences in oral reading expressiveness. However, whole-group, continuous analyses of maternal oral reading expressiveness in relation to toddlers' concurrent language skills revealed that maternal oral reading expressiveness, specifically mean
F
0, significantly contributed to the prediction of toddlers' receptive language skills, accounting for demographic and socioeconomic factors.

Conclusions:

Initial findings suggest that maternal oral reading expressiveness is associated with children's emerging language skills and warrant further investigation of how this relates to broader aspects of children's home language environments. This work carries implications for oral reading expressiveness as one facet of shared reading with potential to facilitate early language skill development.
Unveiling first self‐healing in metallised film capacitor: A macro–micro analysis
Authors: He Yushuang , Wang Feipeng , Du Guoqiang , Pan Lei , Li Jian , Yang Hongming , Zhang Xiao , Zhang Zhicheng , Wang Kaizheng
Published: February 2025

Metallised film capacitors (MFCs) are renowned for their unique self‐healing (SH) properties, which bestow them with exceptional reliability and stability in the face of intense electric fields, high voltages, and pulse power applications. Nonetheless, the exploration of SH characteristics concerning single‐layer dielectric film remains insufficient for advancing MFC reliability evaluation. To establish the theoretical correlation of SH characteristics from the device to the film in the MFCs, this work developed a simulation model to analyse the SH dynamic behaviour in the MFCs. The effects of coupling capacitors, arc resistance and insulation resistance on the macroscopic characteristics (voltage drop and pulse current) are focused during the SH process in MFCs. The results indicate that SH is primarily associated with the voltage drop duration rather than the sampling current. Consequently, the SH process in MFC is characterised as an abrupt decrease in voltage to its minimum value. This refinement enhances the SH energy dissipation model of MFC. The quantified relationship between the macroscopic characteristics and microstructure evolution (polypropylene decomposition and aluminium electrode vaporisation) is established in MFCs under diverse SH energy levels. As SH energy and duration increase, the proportion of energy attributed to polypropylene decomposition increases, resulting in multi‐layer ablation and adhesion within the metallised film and a pronounced deterioration in MFC electrical performance. The examination of macro–micro perspectives sheds new light on the intricate mechanisms governing the SH behaviour in MFCs, offering valuable insights for the advancement of their design, reliability evaluation, and performance optimisation in diverse electrical applications.
IoT‐5G and B5G/6G resource allocation and network slicing orchestration using learning algorithms
Authors: Abba Ari Ado Adamou , Samafou Faustin , Ndam Njoya Arouna , Djedouboum Assidé Christian , Aboubakar Moussa , Mohamadou Alidou
Published: February 2025

The advent of 5G networks has precipitated an unparalleled surge in demand for mobile communication services, propelled by the advent of sophisticated wireless technologies. An increasing number of countries are moving from fourth generation (4G) to fifth generation (5G) networks, creating a new expectation for services that are dynamic, transparent, and differentiated. It is anticipated that these services will be adapted to a multitude of use cases and will become a standard practice. The diversity of these use cases and the increasingly complex network infrastructures present significant challenges, particularly in the management of resources and the orchestration of services. Network Slicing is emerging as a promising approach to address these challenges, as it facilitates efficient Resource Allocation (RA) and supports self‐service capabilities. However, effective network segmentation implementation requires the development of robust algorithms to guarantee optimal RA. In this regard, artificial intelligence and machine learning (ML) have demonstrated their utility in the analysis of large datasets and the facilitation of intelligent decision‐making processes. However, certain ML methodologies are limited in their ability to adapt to the evolving environments characteristic of 5G networks and beyond (B5G/6G). This paper examines the specific challenges associated with the evolution of 5G and B5G/6G networks, with a particular focus on ML solutions for RA and dynamic network slicing orchestration requirements. Moreover, the article presents potential avenues for further research in this domain with the objective of enhancing the efficiency of next‐generation mobile networks through the adoption of innovative technological solutions.
Optimality conditions for global minimizers to a class of convex set optimization problem subjected to geometric constraints
Authors: Nguyen Tung , Pham Duoc , Nguyen Hoi
Published: February 2025

In this paper, we study optimality conditions for both global and approximate minimizers to convex set optimization problems with geometric constraints. We first consider a form of Gerstewitz's nonlinear scalarization function concerning the set-less relation introduced by Kuroiwa. Then, it is employed to construct a type of directional derivative and  sub-gradient for cone-convex set-valued maps.  We also give some properties and usual calculus rules for these concepts. Later, some necessary and sufficient conditions for global and approximate solutions are established. Examples are provided for analyzing and illustrating the obtained results.
Ausfallhonorar in der Bestellpraxis
Authors: Brantz Alina
Published: February 2025

Der Patient erscheint unangekündigt oder nach kurzfristiger Absage nicht zum vereinbarten Termin. Ein solcher Terminausfall führt in Arztpraxen schnell zu wirtschaftlichen Verlusten. Das Honorar dieses Termins fällt ersatzlos weg, wenn der Arzt nicht die Möglichkeit hat, den Termin anderweitig zu vergeben oder der Termin mit einer Doppelbelegung geplant ist. Die Geltendmachung solcher Schäden kommt nach den gesetzlichen Vorschriften über Dienstverträge oder bei Abschluss einer vertraglichen Vereinbarung als sogenanntes Ausfallhonorar in Betracht. Höchstrichterliche Rechtsprechung zu der Frage, ob und unter welchen Voraussetzungen ein Ausfallhonorar in Ansatz gebracht werden kann, existierte bis vor Kurzem nicht. In der amts- und landgerichtlichen Rechtsprechung bestand bereits zuvor Einigkeit über einige Punkte, die es zu beachten gilt, um ein Ausfallhonorar geltend zu machen. Zu unterscheiden ist zwischen zwei in Betracht kommenden Anspruchsgrundlagen. Zum einen die gesetzlichen Vorschriften, dort § 615 S. 1 BGB, oder zum anderen eine vertraglich geschlossene Vereinbarung können als Grundlage für die Geltendmachung dienen. Es stellen sich einige Hürden, die teilweise bereits vor dem Eintritt des eigentlichen Terminversäumnisses zu nehmen sind. Außerdem eignet sich die Geltendmachung nicht in jedem Fachgebiet und bei jeder Praxisorganisation. Erfolgsaussichten bestehen lediglich in sogenannten Bestellpraxen, also solchen Praxen, die Termine exklusiv für einzelne Patienten vergeben.
Abrechnung medizinisch-technischer Innovationen nach der GOÄ
Authors: Tigges Gerrit
Published: February 2025

Nach einleitendem Überblick zum Stand der GOÄ stellt der Beitrag die Grundsätze der Analogberechnung sowie des Zielleistungsprinzips nach der GOÄ dar. Anhand von Beispielen aus der aktuellen Rechtsprechung werden die Möglichkeiten sowie Differenzierungen der (analogen) Abrechnung neuer und innovativer medizinisch-technischer Leistungen aufgezeigt, um daraus Schlussfolgerungen für vergleichbare Sachverhalte zu ziehen.
Transkulturelle Psychotherapie – Informationen, Anlaufstellen und Hilfe im Internet
Authors: Oberländer Nadine
Published: February 2025

Psychische Belastungen in interkulturellen Kontexten entstehen u. a. durch kulturelle Unterschiede, Migrationserfahrungen und Flucht. Menschen mit Migrationshintergrund sind neben sprachlichen Barrieren häufig mit Diskriminierungserfahrung und inneren Konflikten durch Kulturunterschiede konfrontiert. Das Internet bietet wertvolle Informationen und Hilfsangebote, die für interkulturelle Herausforderungen sensibilisieren und die Versorgung verbessern.
A silent opponent: Staphylococcus aureus and its
impact on wrestlers
Authors: Thomas Talia , Moore Angela , Nath Swapan , Kearns Greg
Published: February 2025

Community acquired methicillin resistant Staphylococcus aureus infections
have surged dramatically over the past decade. Athletes in contact sports,
especially wrestlers, represent a unique subset of young, healthy individuals
who are at heightened risk for transmitting methicillin resistant
Staphylococcus aureus. The sport of wrestling has seen a significant
increase in participation, particularly among adolescents, underscoring its
growing popularity and the urgent need to address this issue. Unfortunately, the
rates of community acquired methicillin resistant Staphylococcus aureus
have followed a similar upward trend. Treatment options for community acquired
methicillin resistant Staphylococcus aureus vary, ranging from topical or
systemic antibiotics to more invasive interventions like incision, drainage, and
intralesional injections. Preventive measures are also essential and include
avoiding shared equipment, meticulous mat and gear cleaning, and eliminating
bacterial colonization. While existing research supports the effectiveness of
decolonization strategies in hospital settings, there is a pressing need to
adapt and implement these approaches within the wrestling community. Current
prevention methods, such as mat cleaning and skin checks before competitions,
are insufficient on their own. By adopting more comprehensive decolonization
protocols tailored to the wrestling environment, we can better protect athletes
and reduce the incidence of community acquired methicillin resistant
Staphylococcus aureus skin infections.
Biomarkers for Postoperative Intimal Hyperplasia
Authors: Yamamura Mitsuhiro , Sakaguchi Taichi , Tanaka Hiroe , Watanabe Ken-ichi , Uemura Hisashi , Sakashita Yuji , Teshima Yoshio , Bungo Masashi
Published: February 2025

Interleukin-8 (IL-8) is a neutrophil chemotactic factor produced by vascular endothelial cells. This study aimed to evaluate whether the serum IL-8 level can be the biomarker for postoperative intimal hyperplasia in the rat model. Sixteen male Lewis rats (mean weight: 501 ± 44 g) were subjected in this study. The right epigastric vein graft is interposed into the common femoral artery with 10–0 interrupted sutures, as previously described. Vein grafts from each group were stained with hematoxylin and eosin and Elastica Verhoeff's van Gieson's at 2 and 4 weeks postoperatively. Unoperated right epigastric veins were also examined as a Sham. In Group edaravone, free-radical scavenger, edaravone (Radicut®, Mitsubishi Tanabe Pharma Corp., Osaka Japan) was administered, instead of saline. The initial areas of vein grafts were measured using computerized planimetry (NIH Image Ver. 1.61). Serum IL-8 levels were measured and compared using an unpaired t-test. This study was approved by the Hyogo College of Medicine Animal Research Committee (No. 235). The average intimal area at 4 weeks in Control group was significantly increased compared with that of Sham group (0.43 ± 0.11 vs. 0.00 ± 0.00 mm2, p < 0.01). The average serum IL-8 levels at 4 weeks were also significantly increased, compared with that of Sham group (148 ± 6 vs. 53 ± 14 pg/mL, p < 0.05). The serum IL-8 levels in Group edaravone were appeared to be suppressed but not significant (132 ± 24 pg/mL, p = 0.72). It is very important to detect the biomarker such as the serum IL-8, before the establishment of postoperative intimal hyperplasia.
Partial ampullary endoscopic mucosal resection in patients with difficult biliary cannulation: A prospective cohort study
Authors: Tokmak Salih , Cetin Mehmet Fuat , Sirin Abdullatif , Konur Sevki , Torun Serkan
Published: February 2025

Backgrounds and study aims: Rescue techniques applied in case of cannulation failure are limited in number and have severe limitations. We recently described partial ampullary endoscopic mucosal resection (PA-EMR) as a novel technique for difficult biliary cannulation. We aimed to demonstrate the efficacy and safety of PA-EMR for patients with difficult biliary cannulation in a larger cohort

Patients and methods: We conducted a prospective cohort study at our tertiary-care referral hospital. We recorded demographic factors, procedure-related characteristics, and adverse event rates in patients who received PA-EMR in case of difficult biliary cannulation.

Results: Between June 2021 and June 2022, we performed 1073 consecutive ERCP procedures on 962 patients; 40 patients (12 male, 28 female, with a mean age of 68.1± 4 years) had difficult biliary cannulation and had PA-EMR. Technical success was 100%, and none of the patients required a second session. None of the patients had an adverse event, and we encountered no 30-day mortality. The most typical indication was bile duct stones with 60% (n=24), followed by periampullary tumors with 15% (n=6). The total procedure time was 923 (min-max, 392-1224) seconds.

Conclusions: PA-EMR is an effective and safe rescue technique in patients with difficult biliary cannulation.
Electron temperature gradient instability and transport analysis in NSTX and NSTX-U plasmas
Authors: Clauser C. F. , Rafiq T. , Parisi J. , Avdeeva G. , Guttenfelder W. , Schuster E. , Wilson C.
Published: February 2025

Extensive linear and nonlinear simulations to study electron temperature gradient (ETG) stability and thermal transport in National Spherical Torus Experiment (NSTX) and NSTX-U plasmas were performed using the fully electromagnetic gyrokinetic code CGYRO. Linear simulations were performed to determine ETG thresholds in different discharges, showing that ETG modes in spherical tokamaks can present different scalings compared to conventional aspect-ratio tokamaks. Nonlinear gyrokinetic simulations were conducted for selected cases to calculate electron thermal transport and compare to experimental values. Results are also compared with those of ETG modes in the multi-mode model and the Trapped-Gyro-Landau-Fluid reduced model codes, to better understand their applicability in spherical tokamaks.
Complementary logic-in-memory inverters integrating n-channel and p-channel ferroelectric organic transistors
Authors: Wei Haitian , Lin Yijie , Yan Zhenxiang , Xie Wenfa , Wang Wei
Published: February 2025

The emerging logic-in-memory (LIM) technology is a promising strategy to overcome the von Neumann bottleneck in modern computers. For LIM circuits, the complementary structure is desirable for low-power consumption. To date, there have been rare reports on the n-channel organic thin-film transistor nonvolatile memories (OTFT-NVMs), which is indispensable for building the complementary LIM circuits. In this Letter, we demonstrate a route to achieve the low-voltage operatable n-channel OTFT-NVMs, by blade-coating an ultrathin tetratetracontane buffer layer on the oxygen plasma treated ferroelectric terpolymer insulator with a low coercive field. The n-channel OTFT-NVMs exhibit good performances, with a high electron mobility over 0.1 cm2/V s, highly reliable endurance over 1000 cycles, and highly stable retention over 10 000 s. The mechanism for improving device performances is discussed. Moreover, the mechanism and the route for improving performances are also suitable for p-channel OTFT-NVMs. Furthermore, the LIM architecture-based complementary organic inverters are constructed by integrating the n-channel and p-channel OTFT-NVMs, which can well perform logic and memory operations at the low voltage of 10 V. The work laid the foundation for the development of the LIM circuits.
Anomalous thermal transport in semiconductors induced by aliovalent doping
Authors: Wang Lankun , Zhu Jianbo , Dong Xingyan , Zhu Yu-Ke , Jiao Lei , Xia Boya , Zhou Jiawei , Guo Fengkai , Bordelon Mitchell , Wilson Stephen D. , Cai Wei , Sui Jiehe , Liu Zihang
Published: February 2025

As an effective method for thermal management technologies, doping or substitution has been extensively utilized to reduce the lattice thermal conductivity of various materials. Intensive studies have been conducted about the phonon mechanism of isoelectronic alloying since the 1950s. Very recently, the specific role of aliovalent doping was elucidated in the half-Heusler NbFeSb system. Here, we have theoretically and experimentally investigated the mechanism of reducing thermal conductivity through aliovalent doping by combining first-principles calculations and neutron diffraction studies for the case study of the TiCoSb half-Heusler system. The softening of the acoustic branches induced by aliovalent doping can effectively reduce the phonon group velocities. Moreover, the introduction of compensating defects, resulting from changes in the Fermi level, plays a vital role in decreasing the relaxation time of phonons, as demonstrated by the analysis of neutron powder diffraction. Due to these two factors, doping with adjacent elements results in a significant reduction in lattice thermal conductivity (for instance, Ni doping at the Co site in the TiCoSb half-Heusler system), especially in the low-temperature range. Our findings provide valuable insight into the phonon scattering mechanism in aliovalent-doped materials and demonstrate the role of compensating defects in heat transport, which is applicable to other doped semiconductor systems.
Turbulence of lump, stripe, and soliton waves in Saturn's magnetosphere plasmas
Authors: Alharthi N. S. , Tolba R. E.
Published: February 2025

The Zakharov–Kuznetsov equation, along with its modified forms [the modified Zakharov–Kuznetsov and further modified Zakharov–Kuznetsov equations], is important modeling equations for interpreting different magnetoacoustic waves in plasma. In this study, we established stable broad-ranging soliton solutions, including well-known lump- and stripe-shaped soliton solutions, obtained using the Hirota bilinear (HB) method. The figures in this text show the effect of physical parameters in the plasma system—dispersion and turbulent dispersion coefficients—on wave height. Wave heights remain determinable for different values of the physical parameters and the free parameters associated with them. A three-dimensional (3D) plot of the ascertained solutions clarified the stability points of the equations we studied based on the bifurcation theory. The results for each modeling equation make a significant contribution to the analysis of dust-ion-acoustic waves in plasma in Saturn's magnetosphere. We assert that the HB method is reliable, appropriate, easy to use, and powerful for extracting closed-form soliton solutions.
Gate control of electron correlations towards Mott field effect transistors (MottFET)
Authors: Shoham Lishai , Silber Itai , Tuvia Gal , Baskin Maria , Hwang Soo-Yoon , Choi Si-Young , Han Myung-Geun , Zhu Yimei , Yalon Eilam , Rozenberg Marcelo J. , Dagan Yoram , Trier Felix , Kornblum Lior
Published: February 2025

The modulation of channel conductance in field-effect transistors (FETs) via metal-insulator-semiconductor structures has revolutionized information processing and storage. However, the limitations of silicon-based FETs in electrical switching have driven the search for new materials capable of overcoming these constraints. Electrostatic gating of competing electronic phases in a Mott material near its metal-to-insulator transition (MIT) offers the prospects of substantial modulation of the conducting electrons and electrical resistivity through small changes in band filling. While electrostatic control of the MIT has been previously reported, the advancement of Mott materials toward novel Mott-based transistors, MottFETs requires the realization of their unique physical properties in a solid-state device. In this study, we present gate control of electron correlation using a solid-state device utilizing the oxide Mott system La1−xSrxVO3 as a correlated FET channel. We report on a gate resistance response that cannot be explained in a purely electrostatic framework. This behavior suggests an enhancement in effective mass and a reduction in effective carrier density as the system approaches its insulating state, consistent with theoretical predictions for Mott systems, suggesting at least 100× charge gain originating from the correlated behavior. These preliminary results pave the way toward the development of highly efficient, low-power electronic devices that could surpass the performance bottlenecks of conventional FETs by leveraging the electronic phase transitions of correlated electron systems.
Enhanced approximate Riemann solvers for all-Mach number flows using anti-diffusion coefficients
Authors: Gogoi A. , Mandal J. C.
Published: February 2025

This paper compares the Harten–Lax–Leer–Einfeldt Modified (HLLEM) and Harten–Lax–Leer Convective Pressure Split (HLL-CPS) schemes for Euler equations and proposes improvements for all-Mach number flows. Enhancements to the HLLEM scheme involve adding anti-diffusion terms in the face normal direction and modifying anti-diffusion coefficients for linearly degenerate waves near shocks. The HLL-CPS scheme is improved by adjusting anti-diffusion coefficients for the face normal direction and linearly degenerate waves. Matrix stability, linear perturbation, and asymptotic analyses demonstrate the robustness of the proposed schemes and their ability to capture low Mach flow features. Numerical tests confirm that the schemes are free from shock instabilities at high speeds and accurately resolve low Mach number flow features.
High-pressure modulation of altermagnetism in MnF2
Authors: Fan Zhenyu , Zhang Zhengming , Wang Hongchang , Gong Jianhu , Wang Dunhui , Wang Baomin
Published: February 2025

We investigate the phase transition behavior and electronic band structure of MnF2 under high pressures ranging from 0 to 20 GPa based on first-principles calculations. At ambient pressure, MnF2 in the rutile structure displays antiferromagnetic properties along with significant altermagnetic characteristics. Upon increasing pressure, MnF2 undergoes sequential phase transitions from the rutile structure to the SrI2-type structure and further to the α-PbCl2-type structure. Under high pressure, all three structures of MnF2 exhibit stable altermagnetism, with the maximum spin splitting of 307.5 meV at 3 GPa for the rutile structure, 133.6 meV at 12 GPa for the SrI2-type structure, and 58.4 meV at 20 GPa for the α-PbCl2-type structure. Additionally, our findings suggest that the magnitude of spin splitting can be effectively controlled by modulating the antiferromagnetic exchange interactions and the electron hopping parameters between sublattices. This work elucidates the crystal structure, electronic structure, and altermagnetic properties of MnF2 under high pressure, providing important theoretical foundations for expanding the library of altermagnetic materials.
Particle image velocimetry/planar laser-induced fluorescence applied for the study of hydrodynamic aspects of low-viscosity ratio stratified liquid–liquid flow
Authors: Miranda-Lugo P. J. , Arrollo-Caballero Jorge E. , Rodriguez O. M. H.
Published: February 2025

Stratified liquid–liquid flow is still an open research subject due to the complex interfacial interactions and its hydrodynamic stability in specific operational conditions. Some challenges are predicting velocity profiles related to the average velocities of the phases and the effect of shape factors, capillary instability, and secondary flow on the flow pattern transition. Understanding the hydrodynamics of horizontal stratified liquid–liquid pipe flows is a fundamental step for properly modeling the stability of stratified liquid–liquid flows. Some studies have focused on measuring hydrodynamic characteristics of stratified liquid–liquid flows in horizontal or slightly inclined pipes by combining two-dimensional Particle Image Velocimetry (2-D PIV) and Planar Laser-Induced Fluorescence (PLIF) techniques. Nevertheless, this study represents the first attempt to study the case of two low Eötvös numbers (2.2. and 9.7) and low-viscosity ratio flows via synchronizing those techniques in the streamwise and spanwise directions. The 2-D PIV technique was used to measure two-phase velocity profiles and turbulence statistics at the flow's diametrical vertical plane for stable and unstable stratified flow conditions. Simultaneously, the mean interface height was measured through the PLIF technique and a homemade scanning algorithm that identifies the liquid–liquid interface. In addition, the interface's cross-section curvature radius was measured at the flow's cross-sectional plane. The axial velocity profiles showed an S-shape. The appearance of radial velocity components near the pipe wall or the liquid–liquid interface revealed momentum transfer between the two phases, suggesting the existence of secondary flow. The cross-section curvature radius data revealed that the higher the in-situ water volumetric fractions, the more concave the cross-section interface and the more unstable the stratified flow.
Laminar annular displacement flows with rotating inner cylinder in large annuli
Authors: Sotoudeh Sophia , Izadi Mahdi , Lund Bjørnar , Ytrehus Jan David , Taghipour Ali , Frigaard Ian. A.
Published: February 2025

We present computational results from simulations of displacement flows in inclined and horizontal eccentric annuli, both with and without a rotating inner cylinder. The study is aimed at understanding flows in the industrial process of primary cementing of oil and gas wells. Following from Sotoudeh and Frigaard [“Computational study of Newtonian laminar annular horizontal displacement flows with rotating inner cylinder,” Phys. Fluids 36, 083113 (2024)], we explore larger-scale annuli and flows that are more inertial. These compare favorably with results from a series of displacement flows in a large laboratory experiment. This establishes the utility of the three-dimensional simulations as a tool for in depth understanding of the effects of inner cylinder (casing) rotation. We find that rotation affects the displacement effectiveness directly by adding an azimuthal Couette component to the flow. This moves (advects) the fluids around the annulus, particularly near the inner cylinder wall. For adverse viscosity ratios m, sufficient rotation appears to increase the displacement efficiency, but for large viscosity ratios it is found to sometimes reduce an already effective displacement. These results are all focused at lab-scale experimental annuli. Over the full length of a typical oil or gas well, the casing will rotate many more times during than in an experiment. Thus, our conclusions based on a single annular volume pumped may need modification.
Visible-blind bipolar response photodetector based on GaN/ZnO:Ga/GaAs double heterojunctions for dual-band optoelectronic logic operation
Authors: Wan Peng , Sun Lixiang , Chen Jiadong , Zhang Fazheng , Dai Ruiming , Feng Huijie , Shi Daning , Kan Caixia , Jiang Mingming
Published: February 2025

Bipolar response photodetectors have sparked considerable interest in optical switches, smart chips, and artificial neuroscience, but invisible ones are still scarce. Here, a visible-blind bipolar response photodetector based on GaN/ZnO:Ga/GaAs double heterojunctions is proposed. Under self-powered conditions, the designed photodetector only shows dual-band photoresponse in the ultraviolet (UV) and infrared (IR) spectrum. Specifically, originating from the absorption characteristics and suitable energy band of multilayered structures, it exhibits positive (negative) photocurrents under UV (IR) illumination. The maximum responsivity of 4.7 mA/W (−1.8 mA/W) under the UV (IR) illumination and fast response time (19.6/36.8 μ s) are achieved. Dual-band optoelectronic logic operations, including OR, AND, NOR, NOT, and NAND, are realized with a single photodetector by precisely regulating the UV and IR illumination. This work paves an approach for the development of visible-blind bipolar photodetection and all-in-one optoelectronic logic gates.
Development of sawtooth waveform beam buncher for medical cyclotron accelerator
Authors: Wang Zhiyu , Qiao Zhiguang , Liu Wei , Cai Xiaowei , Wu Qiong , Fu Haoran , Luo Jiebin , Li Haipeng , Wang Sheng
Published: February 2025

A bunching system utilizing a heterodyne combiner is designed to generate a sawtooth waveform with three harmonics to increase the beam current intensity of medical cyclotron accelerators. The design incorporates a low-pass filter, helical bandpass filters, and a broadband matching network, producing a sawtooth waveform exceeding 1200 V, which meets the requirements for efficient bunching. This buncher substitutes the design and manufacturing requirements for high linearity broadband power amplifiers with three narrowband single-frequency power amplifiers for amplification. The digital direct synthesizer achieves coherent amplitude and phase adjustment of these three frequency signals. The broadband matching network is based on transmission line transformers to avoid the design of large-sized coaxial resonant cavities, which satisfy the spatial constraints of the cyclotron injection line.
Stability and drag reduction mechanism of mucus-water interface on underwater vehicle surface
Authors: Zhang Kaisheng , Zhang Chuangchuang , Jiang Wantao , Zhang Jing
Published: February 2025

To research the drag reduction performance and mechanism of the mucus–water interface from the perspective of the stability of the liquid–liquid interface, based on the research method of the horizontal collector interface and the basic theory of microchannel two-phase flow, the mechanical parameters such as viscous force, interfacial tension, and shear force, as well as physical parameters such as the water flow rate, mucus discharge rate, mucus discharge aperture, and mucus properties on the stability of the mucus–water interface were investigated using the computational fluid dynamics software and the designed and constructed test rig for the analysis of the stability of the microscopic interface. The research examines how physical parameters like water flow rate, mucus discharge rate, mucus pore diameter, and mucus properties affect the stability of the mucus–water interface. A test bench was constructed to evaluate how water flow and mucus discharge rate influence drag reduction performance. Results show that the interface is most stable when the water flow rate is 0.1 m/s, the mucus discharge rate is 0.05 m/s, the mucus pore diameter is 0.16 mm, and interfacial tension is 0.08 mN/m, leading to the longest slip length. Increasing mucus discharge velocity, and pore diameter, and using mucus with higher interfacial tension enhances interface stability and increases slip length. The drag reduction mechanism occurs because an increase in slip length reduces the velocity gradient near the surface, which in turn decreases the shear stress in the turbulent boundary layer, enhancing the drag reduction effect. Additionally, mucus with higher dynamic viscosity helps form a uniform layer, improving interface stability and reducing friction from instability. However, it also increases shear force at the mucus–water interface, which may counteract the drag reduction effect.
Transition from featureless turbulence to turbulent Taylor vortices in counter-rotating cylindrical annulus
Authors: Kang Changwoo , Talioua Abdessamad , Prigent Arnaud , Mutabazi Innocent
Published: February 2025

The transition from featureless turbulence to stationary turbulent Taylor vortices in the flow between two counter-rotating coaxial cylinders has been investigated by both experiments and numerical simulations in a given range of the control parameters. Experimental data were obtained from visualization and stereoscopic particle image velocimetry. The flows emerging from featureless turbulence when the inner cylinder rotation is increased are quantified and classified into two regimes: noise-induced patterns (disordered Taylor) and robust coherent vortices (wavy turbulent vortices and stationary turbulent Taylor vortices). Different quantities are analyzed to determine the transition between featureless turbulent state and coherent structures. Numerical data from large eddy simulations reproduce the experimental results and allow for a thorough quantitative characterization of the flow regimes, especially in the near-wall regions. Statistical analysis of fluctuating flow quantities is performed, and it turns out that the flow is dissymmetric near the inner and outer cylinders.
A coplanar electrode operating mode for piezoelectric energy harvesting and self-powered sensing
Authors: Hao Jian , Liu Ping , Gao Guanglong , Gao Qingguo , Yang Jianjun , Liu Liming
Published: February 2025

Piezoelectric semiconductors have emerged as a prominent area of research in recent years due to their unique combination of piezoelectric and semiconductor properties. In this Letter, we propose a piezoelectric device structure featuring coplanar electrodes positioned above the piezoelectric layer. We have conducted a detailed theoretical analysis of the piezoelectric properties of this piezoelectric device. By utilizing a coplanar electrode piezoelectric mode, pressure applied to one electrode generates a potential difference between the two electrodes. Notably, the piezoelectric performance of the device can be adjusted by modifying its structure. Numerical simulations and experimental results indicate that the piezoelectric performance reaches an optimal value when the distance between the electrodes is equal to one-half of the electrode length. Additionally, we have developed a method to enhance the piezoelectric voltage output capability of the device under low load resistance conditions. Specifically, by introducing charge carriers into the piezoelectric layer from the doped silicon substrate, the device's resistance is reduced due to the Schottky contact. The piezoelectric operating mode proposed in this paper facilitates energy harvesting and self-powered sensing, distinguishing it from the d31 and d33 operational modes associated with traditional sandwich device structures, thereby allowing for more versatile device configurations.
Impact of fuel injection temperature dynamics on the stability of liquid oxygen–methane supercritical combustion
Authors: Sharma Abhishek , De Ashoke , Sunil Kumar S.
Published: February 2025

A crucial factor in the stability of high-pressure rocket-scale combustors is the temperature at which fuel is injected. This study investigates its effect on the stability of supercritical liquid oxygen–methane combustion and highlights the impact of shear layer dynamics in cases with lower injection temperatures. The stability features of a rocket-scale combustor operating with multiple injector elements are investigated using a high-fidelity large eddy simulation (LES) framework. The numerical framework combines a flamelet-generated manifold combustion model with complex real gas thermodynamics in a scale-resolving simulation setup. It reproduces the non-equilibrium transcritical injection and supercritical combustion characteristics of supercritical methane–oxygen flames. To ascertain the effect of injection temperature on flame and combustor stability, we perform several LES simulations at various methane injection temperatures and produce a stability map. Our analysis shows extremely unstable flame characteristics at lower fuel injection temperatures that are not seen under typical fuel injection circumstances. Below a specific methane injection temperature, LES captures a high-amplitude, self-sustaining instability. It is determined that the combustor becomes unstable below a specific stability boundary temperature. Detailed spectral and dynamic mode decomposition analysis of the stable and unstable cases reveals the onset of longitudinal acoustic waves in the combustor. Our thorough investigation pinpoints the instability mechanism, emphasizing that the leading causes of this self-sustaining instability in the combustor are a reduced velocity ratio, fuel buildup, and fuel cutoff occurrences.
Experimental study on the aerodynamic and wind-induced vibration characteristics of grooved stay cables
Authors: Liu Qingkuan , Chu Zekai , Sun Yifei , Zhou Ying , Gu Haotian , Ma Jianan
Published: February 2025

Previous studies have shown that grooves can decrease the drag of a circular cylinder (Re = 4.8 × 103–1.2 × 105), suppress vortex-induced vibration and rain-wind-induced vibration, and have potential applications in reducing the drag and damping vibrations of stay cable structures. However, the aerodynamic performance of grooved circular cylinders at high Reynolds numbers (Re = 105–106) remains unknown. Therefore, a series of wind tunnel tests were performed on grooved cables, including measurements of surface pressure, vortex-induced vibration, and dry galloping. Various aerodynamic parameters (such as surface wind pressure distribution, aerodynamic forces, and the Strouhal number), vortex-induced vibration characteristics, and dry galloping characteristics were investigated, and the results were compared with those of standard cables. The results indicated that, relative to standard cables, the average drag coefficient of grooved cables is smaller at low Reynolds numbers, and the drag reduction effect is correlated with the number of grooves, with a maximum drag reduction rate of 47%. The drag reduction effect of the grooved cables gradually decreases as the Reynolds number increases, and the grooved cables stop exerting a drag reduction effect when Re > 3.1 × 105. Compared with standard cables, the circumferential average wind pressure of grooved cables is more stable with respect to the Reynolds number, and the Reynolds number effect is weaker. The maximum amplitudes of the vortex-induced vibrations and dry galloping of the grooved cables are lower than those of standard cables. The optimal suppression efficiencies of vortex-induced vibrations for 16- and 32-grooved cables are 96.0% and 52.0%, respectively, whereas those of dry galloping for these are 75.0% and 81.8%, respectively.
Investigation of far-field underwater explosion shock wave-induced cavitation based on Runge–Kutta discontinuous Galerkin method
Authors: Liu Yun-Long , Hao Qi-Hang , Zhong Qiang , Chen Le-Wen , Kong Qi , Zhang A-Man
Published: February 2025

The shock waves and cavitation of far-field underwater explosion seriously threaten submerged structures. By employing the Runge–Kutta discontinuous Galerkin method to solve a first-order system, we establish a three-dimensional axisymmetric far-field underwater explosion model, which can be coupled with both linear and nonlinear equations of state (EOS) of the fluid. A pressure cutoff model is employed to simulate the cavitation phenomenon near the free surface or structure. Different boundary conditions are applied by setting the values in Guardcell, which is a layer of meshes surrounding the boundary. The high-order and compact features of the discontinuous Galerkin method are fully exploited by introducing the block-based adaptive mesh refinement technology such that the resolution around the shock front and the cavitation regions is improved. The accuracy order, the h-adaptivity refinement, and the cavitation results of the present model are validated by comparing the results of a series of test cases with reference values. By analyzing the results of different cases, we found that it is more economical to improve the resolution by increasing the accuracy order than by refining the mesh. The cavitation region obtained by the Tait EOS is significantly larger than linear EOS in the later stages of evolution. The presence of a spherical shell near the free surface has an impact on the shape and collapse of the bulk cavitation. Furthermore, the expansion and collapse of bulk cavitation also affect the kinematic response of the spherical shell, especially when the spherical shell is closer to the free surface.
Logarithmic structures in the far-field stage of over-tripped boundary layer turbulence
Authors: Chen Letian , Tang Zhanqi , Li Zhenqing , Jiang Nan
Published: February 2025

This study reports on over-tripped boundary layer (OT-BL) turbulence induced by a family of leading-edge wall-mounted tripwires. The friction Reynolds number Reτ is more than twice that of the unperturbed canonical turbulent boundary layer. Despite differences in perturbations, all OT-BLs establish a new logarithmic region in the downstream far field.In far field, both the mean velocity profile and the logarithmic region diagnostic function indicate a significant wall-normal extension of the logarithmic region in OT-BLs. The construction of the logarithmic region is a consequence of the wall-driven mechanism. The extent of the wall-driven region shows weak dependence on the tripwire-induced perturbations. To reveal the structural framework in the logarithmic region, the OT-BLs are reduced into uniform momentum eddies and intra-layer shear interfaces. Uniform momentum eddies show wall-attached behavior in the logarithmic region similar to the canonical situation. The structural framework in the new logarithmic region is proven to be consistent with Prandtl mixing length theory. This demonstrates the upward construction of the structural mixing length framework in the logarithmic region compared to the unperturbed case. The pre-multiplied velocity spectra show the emergence of larger-scale inertial structures in the extended logarithmic region of the OT-BL. The larger-scale inertial motions result in a more scale separation in the logarithmic region and lead to the emergence of an inertial subrange. The interaction between high- and low-speed inertial motions exhibits a compression/stretching mechanism within the inertial subrange and production range. The inertial-driven compression/stretching mechanism is primarily dominated by large-scale motions and weakens as scale decreases.
Polymer degradation behavior in drag-reducing pipe flows based on the Finite Extensible Nonlinear Elastic-Peterlin model
Authors: Chen Yang , Zhang Meiyu , Li Changjun , Nechval Andrey M. , Valeev Anvar R.
Published: February 2025

High-molecular polymers can greatly reduce the turbulent hydraulic resistance in fluid pipe transport. However, during the drag-reducing process, polymers undergo mechanical degradation under strong shear stress in turbulent flow. To reveal the interaction mechanisms between polymer degradation and fluid behavior in turbulent flows, we investigated drag-reducing agents (DRA) degradation behaviors in macroscopic flow-through pipe experiments. Polymer concentration and molecular weight effects have been analyzed, and the experimental results showed that the higher the concentration and molecular weight, the better the shear resistance of the polymers in turbulence. Based on the revised Finite Extensible Nonlinear Elastic-Peterlin (FENE-P) model by degraded polymer solution rheological parameters, the drag reduction process of both undegraded and degraded viscoelastic polymer solutions has been simulated. Mean velocity profile, turbulent intensity, turbulent kinetic energy, and turbulent dissipation rate have been obtained, which reveal the polymer degradation behavior in drag-reducing pipe flows. A mechanism of drag reduction failure caused by changes in molecular coil conformation and chain breakage has been proposed, which can be used to explain and predict the polymer degradation process.