bluuebunny/crossref_metadata_2025 huggingface dataset:
An activity scheduling and multi‐agent micro‐simulation platform (ASMMSP) based on long‐term cellular data and considering multi‐mode transfer
Authors: Zhou Jianyao , Yang Fei , Guo Yudong , Wang Lilei , Yao Zhenxing
Published: December 2024

With the growth of urban residential density, cities have developed into metropolitan, resulting in increasingly complex individual travel behaviours. These developments pose challenges to current simulation models in activity scheduling. This paper proposed an activity scheduling and multi‐agent micro‐simulation platform (ASMMSP). By incorporating long‐term cellular data, the platform can eliminate the reliance on personal attributes in activity scheduling, which improves the simulation flexibility and accuracy. ASMMSP also focuses on transfer behaviours between different travel modes. The platform comprises three systems: agent, public transportation, and road network. At each moment, agents evaluate their current states and activity schedules, then change schedules based on the comparison results, current travel conditions, and historical travels. ASMMSP reconstructs the traffic condition within the research area by integrating the current traffic flow and activity schedules iteratively. Furthermore, ASMMSP allows for observation of real‐time traffic conditions. It also enables adjustments to public transportation, road network structure, and traffic volume, which can simulate the traffic impact from emergencies, gatherings, road maintenance, and public transportation adjustments. These functions support traffic models applied in traffic planning, development, and construction. Finally, this paper demonstrates the above capabilities through two case studies in the first ring road of Chengdu.
A calibration approach for compensating hysteresis and nonlinearity error in an MEMS based instrument for porewater pressure monitoring
Authors: Barzegar Milad , Gharehdash Saba , Timms Wendy
Published: December 2024

Micro‐electro‐mechanical system (MEMS) technology is becoming increasingly popular in geotechnical and hydrological monitoring due to their distinct features, including its small size, low cost, low energy consumption, and resistance to vibration shock. Due to the nature of design, they exhibit a series of errors, and most importantly, hysteresis and nonlinearity, which should be compensated before any practical application in order to achieve the highest degree of accuracy and precision. This article proposes a practical approach to enhance the accuracy of a newly developed MEMS instrument for groundwater monitoring. The hysteresis and nonlinearity errors were compensated using an integrated two‐step approach with an optimized Preisach model and an optimized spline approximation, respectively. A hybrid differential evolution‐hill climbing algorithm was utilized to achieve optimum models. This optimization algorithm integrates global and local search, offering higher accuracy and computational stability with a lower calibration point requirement. Analysing the results indicates that the nonlinearity error shows an improvement of more than 94% and hysteresis decreased up to 67%. The results illustrate that the compensation can be performed very well using the proposed methodology with lower uncertainty, mean square error, and standard deviation compared to non‐optimized models.
Magnetic connectivity of coronal loops and flare-accelerated electrons in a B-class flare
Authors: Bröse M. , Vocks C. , Warmuth A. , Mann G. , Dabrowski B. , Krankowski A. , Magdalenić J. , Bisi M. M. , Rothkaehl H. , Zucca P.
Published: December 2024

Context. In solar flares, non-potential magnetic field energy is transferred to particle acceleration, heating, and radiation. Multi-wavelength observations of the solar corona in extreme ultraviolet (EUV) and X-ray show the consequences of magnetic reconfiguration in lower heights, while radio observations contain information about the access of flare-accelerated electrons to greater heights in the solar atmosphere. Signs of downward and upward particle propagation do not always appear symmetrically, they depend on the acceleration process, the sensitivity of the instruments, and the magnetic connectivity. The magnetic connectivity in various flare phases is therefore a key element to study in order to gain a better understanding of combined flare observations.

Aims. We aim to draw conclusions about the magnetic connectivity of specific coronal loops in the active region, the acceleration region, and the higher corona with respect to different phases of the flare process.

Methods. We investigate the evolution of particle acceleration, loops heated by the energy release, and the trajectories of flare-accelerated electrons observed up to one solar radius (1 RS) above the active region in a B-class flare on 6 June 2020. We studied the downward particle acceleration and thermal evolution with observations by the Spectrometer/Telescope for Imaging X-rays and with a reconstruction code based on EUV observations. Traces of flare-accelerated electrons, namely, type-III radio bursts, were investigated with a spectroscopic solar dynamic radio imager (LOw Frequency ARray). The radio source positions in heights of 0.4 RS–1.0 RS were compared with the thermal evolution of coronal loops and with a solar magnetic field model.

Results. In this flare event, similar magnetic reconnection processes and accompanied heating processes are triggered several times. For loops and periods with access to the higher corona, type-III bursts from similar reconnection process are emitted along similar propagation trajectories. There are no radio bursts associated with the heating process of the main flaring loop.

Conclusions. In this event, the large-scale magnetic field is rather stable and seems not to be affected by the flare. The access to loops reaching heights of half a solar radius or more is suppressed during the main flare phase for flare-accelerated electrons. This may lead to more effective heating and absent type-III radio bursts between 20 MHz and 85 MHz.
Exploring the non-thermal physics behind the pulsar wind nebula PSR J2030+4415 through radio observations
Authors: Paredes J. M. , Benaglia P. , Bosch-Ramon V. , Tej A. , Saha A. , Martí J. , Bordas P.
Published: December 2024

Context. PSR J2030+4415 is a gamma-ray pulsar with an X-ray pulsar wind nebula elongated along the north-south direction. The system shows a prominent X-ray filament oriented at an angle of 130° to the nebula axis.

Aims. To improve our understanding of the non-thermal processes occurring in the pulsar wind nebula, we attempted to determine the possible existence of a radio counterpart, study its morphology, and obtain restrictive upper limits of the pulsar and filament emission at radio wavelengths.

Methods. We performed observations of the pulsar PSR J2030+4415 and its surroundings with the upgraded Giant Metrewave Radio Telescope (uGMRT) at two frequency bands, and put the results in context with findings at other wavelengths.

Results. We obtained radio images at 736 and 1274 MHz that reveal a structure trailing the pulsar, with a morphology overlapping the X-ray nebula. This radio structure is the radio counterpart of the X-ray pulsar wind nebula. The derived spectral index along this structure shows spatial variation. There are no hints of the pulsar and the filament at any of the explored radio frequencies, but we obtained restrictive upper limits. A physical scenario that combines the radio and the X-ray observations, and consistent with IR data, of the nebula and the filament is presented. We propose that particle acceleration occurs in the nebula tail due to the presence of a re-collimation shock, and the highest energy particles gradually escape from it through energy-dependent diffusion. We also find a lower limit in the energy of the particles escaping along the X-ray filament of ~GeV.
Tunneling barriers in an extended Marcus theory of electron transfer: Incorporating effects of the bridging medium
Authors: Kumar Ravinder , Venkatramani Ravindra
Published: December 2024

The Marcus semi-classical and quantum theories of electron transfer (ET) have been extensively used to understand and predict tunneling ET reaction rates in the condensed phase. Previously, the traditional Marcus two-state model has been extended to a three-state model, which assumes a harmonic dependence of donor (D), bridge (B), and acceptor (A) free energies on the reaction (e.g., solvent polarization) coordinate. Here, we generalize the previously proposed three-state extended Marcus model (EMM) to an (N + 2)-state model for N bridge sites separating the D from the A. Using the EMM, an analytic expression for the electron tunneling barrier is derived. The EMM model predicts that both the relative thermodynamics of the D–A states and B state reorganization energies can influence the D–A electronic coupling. We discuss signatures of bridge state thermal fluctuations using the EMM on the driving force and distance dependence of ET rates, which can be tested experimentally.
Boosting cation mobility in sol-gel derived organic–inorganic hybrid solid electrolytes through physical conditioning
Authors: Keshishian Vazrik , Wang Guangyu , Kieffer John
Published: December 2024

Organic–inorganic hybrid materials are explored for application as solid electrolytes for lithium-ion batteries. The material consists of a porous silica network, of which the pores are infiltrated by poly(ethylene oxide) and lithium perchlorate. The synthesis involves two steps: First, the inorganic backbone is created by the acid-catalyzed sol-gel synthesis of tetraethyl orthosilicate to ensure continuity of the backbone in three dimensions. In the second step, the polymer and salt are imbued into the porous backbone via solvent exchange. During drying, the cylindrical disk-shaped specimens shrink mainly in the radial direction, which results in spatially non-uniform structural developments. While this inhomogeneity is not discernible in the material’s chemical compositional or thermal properties, it is manifest in its ionic conductivity and adiabatic elastic modulus. The ionic conductivity in the center of the specimens is projected to be between one and two orders of magnitude higher than the measured average across the sample diameter. The process that yields a structure with enhanced ionic mobility during post-synthesis physical conditioning is inferred from careful analysis and numerical interpretation of measurable quantities, and the implications for the design of nanostructured hybrid electrolytes with high ionic conductivity are discussed.
Modulating spin-valley relaxation in WSe2 with variable thickness VOPc layers
Authors: Lubert-Perquel Daphné , Cho Byeong Wook , Phillips Alan J. , Lee Young Hee , Blackburn Jeffrey L. , Johnson Justin C.
Published: December 2024

Combining the synthetic tunability of molecular compounds with the optical selection rules of transition metal dichalcogenides (TMDCs) that derive from spin-valley coupling could provide interesting opportunities for the readout of quantum information. However, little is known about the electronic and spin interactions at such interfaces and the influence on spin-valley relaxation. In this work, vanadyl phthalocyanine (VOPc) molecular layers are thermally evaporated on WSe2 to explore the effect of molecular layer thickness on excited-state spin-valley polarization. The thinnest molecular layer supports an interfacial state which destroys the spin-valley polarization almost instantaneously, whereas a thicker molecular layer results in longer-lived spin-valley polarization than the WSe2 monolayer alone. The mechanism appears to involve a tightly bound species at the molecule/TMDC interface that strengthens exchange interactions and is largely avoided in thicker VOPc layers that isolate electrons from WSe2 holes.
pH, pOH shift and electroconvection of strong and weak electrolytes under ion concentration polarization
Authors: Sun Runze , Gou Yixing , Sauret Emilie , Gu Yuantong , Li Zirui
Published: December 2024

Ion concentration polarization (ICP) phenomenon near permselective membranes and associated electroconvection contributes greatly to ion enrichment, desalination, and biomolecular separation. Despite extensive studies on ion transport and fluid dynamics near the ion exchange membrane (IEM) surface, the influence of hydrolysis and buffer reactions on pH changes and electroconvection remains unclear. This study investigates the pH variations and electroconvection changes in different electrolytes under ICP, through numerical simulations in strong (NaCl) and weak electrolytes (Na2HPO4). Our findings reveal that the free ions produced by reactions increase the electrical conductivity, significantly boosting the current by approximately 14.82% in weak electrolyte in the overlimiting current (OLC) regime. The vortex velocity generated by electroconvective instability also increases by two times at the threshold voltage of 23 times the thermal voltage (25.8 mV). Additionally, the decrease in ion concentration during the ICP causes a significant pH and pOH surge in the quasi-equilibrium electric double layer (QE-EDL) and extended space charge (ESC) region, causing the water self-ionization constant (pKw) to surpass 14. Hydrolysis reactions release H+, reducing the pH surge by 0.5 and raising the OH− concentration in the diffusion boundary layer (DBL) region, resulting in a pOH of 6.5, which is higher than that of the bulk solution. In Na2HPO4 solution, weak acid dissociation reactions confine pH changes to the QE-EDL and ESC regions, maintaining pH stability in the DBL region. It was also found that at the boundary of the DBL region, the disruption of electro-neutrality results in the highest dissociation reaction rates. This research highlights the interplay of buffer reactions, hydrolysis, pH changes, and electroconvection near the IEM surface, with implications for applications involving ion transport and pH control.
Decomposition of friction coefficients to analyze hydration effects on a C60(OH)n
Authors: Iwashita Tomoya , Uematsu Yuki , Terazima Masahide , Akiyama Ryo
Published: December 2024

To analyze hydration effects on macromolecular diffusion, the friction coefficients of macromolecules were examined using molecular dynamics simulations with an all-atom model. In the present study, a method was introduced to decompose the molecular friction coefficient into the contributions for each site on the macromolecule. The method was applied to several fullerenols in ambient water. The friction coefficients for the hydrophilic part, such as the OH group, were larger than those for the hydrophobic part, such as the C. The hydration effect did not depend only on the kind of functional group but also on the surface roughness. This approach would be useful in explaining the experimentally observed large changes in diffusion coefficients of proteins that were accompanied by conformation changes.
Global prediction of sub-relativistic and relativistic electron fluxes in the geosynchronous orbit using artificial neural networks
Authors: Zou Zhengyang , Zhang Longji , Zuo Pingbing , San Wen , Yuan Qitong , Zhu Beiqing , Hu Jiahui
Published: December 2024

High-energy particles in geosynchronous orbit (GEO) present significant hazards to astronauts and artificial satellites, particularly during extreme geomagnetic activity conditions. In the present study, based on observations onboard the GOES-15 (Geostationary Operational Environmental Satellites) spanning from 2011 to 2019 as well as the historical values of solar wind and geomagnetic activity indices, an artificial neural network model was established to predict the temporal evolution of the GEO sub-relativistic and relativistic (>0.8 MeV and >2 MeV) electron fluxes one day in advance. By adding the last-orbital observations of electron flux in each of all 24 different magnetic local times (MLTs) and its two MLT-adjacent values into inputs, the current model can provide accurate predictions with an MLT resolution of one hour for the first time. Moreover, it achieves the best performance in comparison with previous methods, with overall root mean square errors of 0.276 and 0.311, prediction efficiencies of 0.863 and 0.844, and Pearson correlation coefficients of 0.930 and 0.921 for >0.8 MeV and >2 MeV electrons, respectively. More than 99% of the samples exhibit an observation-prediction difference of less than one order of magnitude, while over 90% demonstrate a difference of less than 0.5 order. Further analysis revealed that it can precisely track the global variations of the electron flux during both quiet times and active conditions. The present model would be an important supplement for examining the temporospatial variations of inner magnetospheric particles and helping to establish a warning mechanism for space weather disaster events.
Population encoding of observed and actual somatosensations in the human posterior parietal cortex
Authors: Chivukula Srinivas , Aflalo Tyson , Zhang Carey , Rosario Emily R. , Bari Ausaf , Pouratian Nader , Andersen Richard A.
Published: December 2024

Cognition relies on transforming sensory inputs into a generalizable understanding of the world. Mirror neurons have been proposed to underlie this process, mapping visual representations of others’ actions and sensations onto neurons that mediate our own, providing a conduit for understanding. However, this theory has limitations. Here, we hypothesize that mirror-like responses represent one facet of a broader framework in which our brains engage internal models for cognition. We recorded populations of single neurons in the human posterior parietal cortex (PPC) of a brain–machine interface clinical trial participant implanted with a microelectrode array while she either experienced actual touch, or observed diverse tactile stimuli applied to other individuals. Two body locations were tested, on each of the participant and other individuals. Some neurons exhibited mirror-like properties, consistent with earlier literature. However, they were fragile, breaking with increased task complexity. Population responses were better characterized by generalizable and compositional basic-level features encoded within neural subspaces. These features enable the population to respond to diverse actual and observed touch stimuli and are recruited similarly for similar forms of touch. Mirror-like neurons belong within these subspaces, contributing more globally to compositionality and generalizability. We speculate that at a population-level, human PPC manifests an internal model for touch, and that cognition unfolds in the high-level human cortex by versatility in its representational building blocks. In a broad sense, we speculate that the population features we demonstrate support a broad mechanism by which the high-level human cortex enables understanding.
How and why funders support engaged research
Authors: Bednarek Angela T. , Miyamoto Ben , Corbett Kristin , Hudson Charlotte , Scarrow Gayle , Brass Maeghan , DuMont Kim , Holmes Bev , Supplee Lauren , McLean Robert , Bhatia Jaspal , Chappell Shamira , Gorman Vélez Maggie , Kolavalli Chhaya
Published: December 2024

Research that better aligns policy, practice, and research communities is gaining momentum around the world. This includes engaged research strategies that bring partners, and their diverse perspectives and kinds of knowledge, together to shape research agendas with on-the-ground-needs and to create dynamic problem-solving processes. These approaches aim to generate more equitable and effective solutions to societal challenges. Although many of these partnered strategies have a longstanding history, entrenched research cultures, practices, and institutional structures stand in the way of scaling them. Given the outsized role funders play in shaping research efforts, funders are a critical lever for change. This perspective describes the efforts of a global collaborative of philanthropic and public funders who are adapting their practices, supporting the development of infrastructure (e.g., capacity-strengthening, facilitation expertise, processes to guide relational work, etc.), and targeting system-level challenges to enable engaged research to maximize its potential. The authors integrate insights from different issue areas, geographies, and funding areas to provide concrete examples of funder activities that support engaged research and to suggest areas for further action. Recommendations include scaling changes in funding practices, deepening understanding of how and when engaged research leads to improved outcomes, and reshaping how success is defined and measured.
Oppositional and competitive instigation of hippocampal synaptic plasticity by the VTA and locus coeruleus
Authors: Hagena Hardy , Manahan-Vaughan Denise
Published: December 2024

The novelty, saliency, and valency of ongoing experiences potently influence the firing rate of the ventral tegmental area (VTA) and the locus coeruleus (LC). Associative experience, in turn, is recorded into memory by means of hippocampal synaptic plasticity that is regulated by noradrenaline sourced from the LC, and dopamine, sourced from both the VTA and LC. Two persistent forms of synaptic plasticity, long-term potentiation (LTP), and long-term depression (LTD) support the encoding of different kinds of spatial experience. To what extent the VTA and the LC influence the direction of change of synaptic plasticity and therefore the content of stored experience is not clear. Here, we report that test-pulse activation of Schaffer-collateral–CA1 synapses of freely behaving male rats, in conjunction with VTA stimulation, results in LTP (>24 h), whereas concomitant hippocampal afferent and LC stimulation results in LTD (>24 h). Effects are frequency-dependent (1 to 50 Hz) and competitive: high-frequency (25 Hz), but not low-frequency (5 Hz) optogenetic activation of tyrosine hydroxylase-positive (TH+) neurons in the VTA, results in D1/D5R-dependent LTP, whereas 5 Hz (but not 1, or 25 Hz) activation of TH+ neurons in the LC results in hippocampal LTD that is both D1/D5 and β-AR-dependent. These results suggest that the VTA and LC do not work in synergy, but rather function in a competing fashion to drive different forms of information encoding through synaptic plasticity. Our findings indicate that information transmitted by the VTA and LC is likely to play a decisive role in the shaping of hippocampal information storage and the nature of learned experience.
Protein dynamics underlies strong temperature dependence of heat receptors
Authors: Mugo Andrew Njagi , Chou Ryan , Qin Feng
Published: December 2024

Ion channels are generally allosteric proteins, involving specialized stimulus sensor domains conformationally linked to the gate to drive channel opening. Temperature receptors are a group of ion channels from the transient receptor potential family. They exhibit an unprecedentedly strong temperature dependence and are responsible for temperature sensing in mammals. Despite intensive studies, however, the nature of the temperature sensor domain in these channels remains elusive. By direct calorimetry of TRPV1 proteins, we have recently provided a proof of principle that temperature sensing by ion channels may diverge from the conventional allosterity theory; rather it is intimately linked to inherent thermal instability of channel proteins. Here, we tackle the generality of the hypothesis and provide key molecular pieces of evidence on the coupling of thermal transitions in the channels. We show that while wild-type channels possess a single concerted thermal transition peak, the chimera, in which strong temperature dependence becomes disrupted, results in multitransition peaks, and the activation enthalpies are accordingly reduced. The data show that the coupling with protein unfolding drives up the energy barrier of activation, leading to a strong temperature dependence of opening. Furthermore, we pinpoint the proximal N-terminus of the channels as a linchpin in coalescing different parts of the channels into concerted activation. Thus, we suggest that coupled interaction networks in proteins underlie the strong temperature dependence of temperature receptors.
Pseudogap in electron-doped cuprates: Strong correlation leading to band splitting
Authors: Horio Masafumi , Sakai Shiro , Suzuki Hakuto , Nonaka Yosuke , Hashimoto Makoto , Lu Donghui , Shen Zhi-Xun , Ohgi Taro , Konno Takuya , Adachi Tadashi , Koike Yoji , Imada Masatoshi , Fujimori Atsushi
Published: December 2024

The pseudogap phenomena have been a long-standing mystery of the cuprate high-temperature superconductors. The pseudogap in the electron-doped cuprates has been attributed to band folding due to antiferromagnetic (AFM) long-range order or short-range correlation. We performed an angle-resolved photoemission spectroscopy study of the electron-doped cuprates Pr

1.3−
x

La
0.7
Ce

x

CuO
4
showing spin-glass, disordered AFM behaviors, and superconductivity at low temperatures and, by measurements with fine momentum cuts, found that the gap opens on the unfolded Fermi surface rather than the AFM Brillouin zone boundary. The gap did not show a node, following the full symmetry of the Brillouin zone, and its magnitude decreased from the zone-diagonal to (
π
,0) directions, opposite to the hole-doped case. These observations were reproduced by cluster dynamical-mean-field-theory calculation, which took into account electron correlation precisely within a (CuO
2
)
4
cluster. The present experimental and theoretical results are consistent with the mechanism that electron or hole doping into a Mott insulator creates an in-gap band that is separated from the upper or lower Hubbard band by the pseudogap.
Tungsten is utilized for lactate consumption and SCFA production by a dominant human gut microbe
Eubacterium limosum
Authors: Putumbaka Saisuki , Schut Gerrit J. , Thorgersen Michael P. , Poole Farris L. , Shao Nana , Rodionov Dmitry A. , Adams Michael W. W.
Published: December 2024

Eubacterium limosum
is a dominant member of the human gut microbiome and produces short-chain fatty acids (SCFAs). These promote immune system function and inhibit inflammation, making this microbe important for human health. Lactate is a primary source of gut SCFAs but its utilization by
E. limosum
has not been explored. We show that
E. limosum
growing on lactate takes up added tungstate rather than molybdate and produces the SCFAs acetate and butyrate, but not propionate. The genes encoding an electron bifurcating, tungsten-containing oxidoreductase (WOR1) and a tungsten-containing formate dehydrogenase (FDH), along with an electron bifurcating lactate dehydrogenase (LCT), lactate permease, and enzymes of the propanediol pathway, are all up-regulated on lactate compared to growth on glucose. Lactate metabolism is controlled by a GntR-family repressor (LctR) and two global regulators, Rex and CcpA, where Rex in part controls W storage and tungstopyranopterin (Tuco) biosynthesis. Tuco-dependent riboswitches, along with CcpA, also control two iron transporters, consistent with the increased iron demand for many iron-containing enzymes, including WOR1 and FDH, involved in SCFA production. From intracellular aldehyde concentrations and the substrate specificity of WOR1, we propose that WOR1 is involved in detoxifying acetaldehyde produced during lactate degradation. Lactate to SCFA conversion by
E. limosum
is clearly highly tungstocentric and tungsten might be an overlooked micronutrient in the human microbiome and in overall human health.
Deep conservation complemented by novelty and innovation in the insect eye ground plan
Authors: Gao Ke , Donati Antoine , Ainsworth Julia , Wu Di , Terner Eleanor R. , Perry Michael W.
Published: December 2024

A spectacular diversity of forms and features allow species to thrive in different environments, yet some structures remain relatively unchanged. Insect compound eyes are easily recognizable despite dramatic differences in visual abilities across species. It is unknown whether distant insect species use similar or different mechanisms to pattern their eyes or what types of genetic changes produce diversity of form and function. We find that flies, mosquitos, butterflies, moths, beetles, wasps, honeybees, and crickets use homologous developmental programs to pattern their retinas. Transcription factor expression can be used to establish homology of different photoreceptor (PR) types across the insects: Prospero (Pros) for R7, Spalt (Sal) for R7+R8, and Defective proventriculus (Dve) for R1-6. Using gene knockout (CRISPR/Cas9) in houseflies, butterflies, and crickets and gene knockdown (RNAi) in beetles, we found that like
Drosophila
, EGFR and Sevenless (Sev) signaling pathways are required to recruit motion and color vision PRs, though
Drosophila
have a decreased reliance on Sev signaling relative to other insects. Despite morphological and physiological variation across species, retina development passes through a highly conserved phylotypic stage when the unit eyes (ommatidia) are first patterned. This patterning process likely represents an “insect eye ground plan” that is established by an ancient developmental program. We identify three types of developmental patterning modifications (ground plan modification, nonstochastic patterns, and specialized regions) that allow for the diversification of insect eyes. We suggest that developmental divergence after the ground plan is established is responsible for the exceptional diversity observed across insect visual systems.
Raman activity and high electron mobility of piezoelectric semiconductor GaSiX2 (X = N, P, and As) toward flexible nanoelectronic devices
Authors: Vu Tuan V , Hiep Nguyen T , Vi Vo T T , Phuc Huynh V , Kartamyshev A I , Hieu Nguyen N
Published: December 2024

Inspired by the urgent demand for novel multifunctional materials in advanced technology applications, herein, first-principles calculations are utilized to construct new two-dimensional GaSiX
2 (X = N, P, As) monolayers. After optimizing the GaSiX
2 crystal structures, their stabilities, Raman responses, piezoelectricity, and electronic/transport characteristics are systematically studied. Results from phonon dispersions, ab initio molecular dynamics simulations, elastic constants, and cohesive energies confirm the good dynamic, thermal, energetic, and mechanical stabilities of the proposed GaSiX
2 monolayers. Based on the Heyd–Scuseria–Ernzerhof approach, the GaSiX
2 exhibit semiconductor behaviors with favorable bandgaps for absorption of the visible spectrum of 1.82 for GaSiP2 and 1.43 eV for GaSiAs2 monolayer. In addition, the GaSiX
2 monolayers also show piezoelectric effects, and high in-plane piezoelectric coefficients d
11 are found for the GaSiP2 (−1.16

pm

V

−
1

) and GaSiAs2 (−1.26

pm

V

−
1

). The carrier mobilities of the GaSiX
2 are estimated by the deformation potential method for their transport properties. Along two in-plane transport directions, the carrier mobilities of the GaSiX
2 are anisotropy for holes and electrons. GaSiP2 and GaSiAs2 show large electron mobilities along the x axis of 2816.99 and 1211.41 cm2V−1s−1, respectively. Thus, the GaSiP2 and GaSiAs2 monolayers not only have high anisotropic electron mobilities but also favorable bandgaps and large piezoelectric coefficients, indicating potential applications of GaSiP2 and GaSiAs2 in electronic, photovoltaic, and piezoelectric devices. The findings of this study may provide insights into the GaSiX
2 monolayers for multifunctional applications.
High-performance solar-blind ultraviolet photodetector arrays based on two-inch ϵ-Ga2O3 films for imaging applications
Authors: Yang Yuxia , Han Dongyang , Wu Simiao , Lin Haobo , Zhang Jianguo , Zhang Wenrui , Ye Jichun
Published: December 2024

To achieve high-quality solar-blind ultraviolet (UV) imaging applications based on ultrawide bandgap semiconductor photodetectors, it is crucial to fabricate highly uniform wafer-scale films. In this work, we demonstrate the fabrication of exceptionally uniform two-inch ϵ-Ga2O3 thin films on sapphire substrates using an off-axis pulsed laser deposition method. The two-inch ϵ-Ga2O3 films exhibit remarkable uniformity across key parameters, including thickness, crystalline quality, bandgap, and surface roughness, with an inhomogeneity ratio less than 5%. Additionally, these films are preferentially oriented along the (001) crystal plane. At 20 V bias, the individual ϵ-Ga2O3 photodetector demonstrates outstanding solar-blind UV photodetection performance, with a responsivity of 52.77 A W−1 at 240 nm, an external quantum efficiency of 2.7 × 104%, a dark current of 5.5 × 10−11 A and a UV–visible rejection ratio of 1.2 × 104. Furthermore, the 10 × 10 photodetector arrays fabricated on two-inch ϵ-Ga2O3 films exhibit highly uniform photodetection performance, with photocurrent deviations remaining within one order of magnitude and a maximum standard deviation of ∼8%. High-contrast optical imaging of the letters of ‘NIMTE’ is successfully achieved using the 10 × 10 photodetector arrays. This work provides valuable insights for fabricating wafer-scale uniform ϵ-Ga2O3 films and achieving high-quality solar-blind UV imaging applications.
Coexistence of Kondo effect and non trivial Berry phase in Gd doped Bi2Se3: an ARPES and magneto-transport study
Authors: Ghosh Swayangsiddha , Singh Rahul , Dixit Srishti , Kumar Shiv , Kumar Yogendra , Shimada Kenya , Kumar Ghosh Anup , Lakhani Archana , Chatterjee Sandip
Published: December 2024

The presence of magnetic impurities in topological insulators can disrupt their time reversal symmetry and lead to the emergence of an energy gap. This study delves into the energy band structure and the Kondo effect through the introduction of Gadolinium (Gd) magnetic perturbations (at levels of

x
=
0.1
,
0.16

) into a pure Bi2Se3 single crystal. In the case of the Bi1.9Gd0.1Se3 (5%) single crystal, the Kondo effect becomes observable at temperatures below 50 K. However, the unaltered parent and Bi1.84Gd0.16Se3 (8%) exhibit typical metallic behavior. The pure sample displays the highest magnetoresistance (MR) of around 225% and demonstrates quantum oscillations driven by a nontrivial berry phase. The sample doped with 5% Gd undergoes a transition from negative MR to positive MR due to a presence of mixed magnetic state resulting from the opening of a gap at the Dirac point. This gap opening is confirmed through angle-resolved photoemission spectroscopy (ARPES) measurements. The comparison of the parameters obtained from the SdH and ARPES measurements, the reduction in the

k

F

values in the magnetotransport measurements is likely due to the band bending induced by the Schottky barrier. Thermoelectric properties are assessed across all prepared samples. The undoped sample displays the highest Seebeck coefficient and power factor values of

−
398.02
μ

V K

−
1

and

6.83

mW

mK

−
2

, respectively, at room temperature. These values are notably high for thermoelectric applications at room temperature.
Modeling of oriented growth of YBCO film deposited by MOD on STO substrate
Authors: Angelis Michele De , Pinto Valentina , Celentano Giuseppe , Tomellini Massimo
Published: December 2024

In this work, we present experimental data on the chemical solution deposition of superconducting YBa2Cu3O7−δ
(YBCO) films by the low fluorine metal–organic decomposition technique. The growth of YBCO film on SrTiO3 (STO) single crystal has been studied with particular attention to the degree of crystal orientation, along either the a or c axes, by varying the crystallization temperature and water partial pressure. The experimental data have been interpreted using a model based on the thermodynamics and kinetics of YBCO nucleation at solid surfaces. In the present form, the model has been reformulated to be more versatile for describing kinetic data. In addition, the description of the experimental data through the model requires considering the composition of Barium oxyfluoride as a function of water partial pressure, the adhesion work of YBCO/STO interface, the crystallization temperature and the partial pressure of water. The present study shows that a deeper understanding of the nucleation mechanism can lead to the improvement not only of the YBCO superconducting properties but also of the process robustness and reproducibility.
Wide temperature multi-condition SOC estimation for Li-ion batteries based on F-FOMIAEKF
Authors: Li Junjie , Zhou Jun , Wu Xing , Liu Tao
Published: December 2024

The state of charge (SOC) of the batteries is critical to obtain the operating parameters of the battery system and optimize the control. The mainstream research on SOC estimation is based on the integer order circuit model, and the fractional order impedance model is rarely studied at present. Combined with the shortcomings of the extended Kalman filter (EKF), in this paper, a new adaptive EKF algorithm with a forgetting factor is proposed based on the fractional 2-order model (F-FOMIAEKF), which can accurately estimate the SOC of lithium-ion batteries under wide temperature and multiple operating conditions. In the SOC estimation algorithm, because the new measurement data contributes to enhancing parameter estimation accuracy, the outdated historical data may accumulate errors, resulting in data saturation, so that the estimated value deviates greatly from the actual value. To address this notable issue, this paper integrates the multi-innovation theory within the EKF framework and introduces a forgetting factor to reduce the weight of historical data in the overall data. Simultaneously, the process noise and measurement noise are adaptively adjusted, resulting in the proposed F-FOMIAEKF. The results indicate that the method proposed in this paper can get rid of the limitation that the order of integer order calculus is an integer and can effectively improve the drawback of the low utilization rate of historical data in EKF. Meanwhile, it can accurately reflect the internal state of the power batteries and accurately estimate SOC under wide temperatures and multiple operating conditions.
High-resolution hemodynamic estimation from ultrafast ultrasound image velocimetry using a physics-informed neural network
Authors: Liang Meiling , Liu Jiacheng , Wang Hao , Chu Hanbing , Zhu Mingting , Jiang Liyuan , Zong Yujin , Wan Mingxi
Published: December 2024

Objective. Estimating the high-resolution (HR) blood flow velocity and pressure fields for the diagnosis and treatment of vascular diseases remains challenging. Approach. In this study, a physics-informed neural network (PINN) with a refined mapping capability was combined with ultrafast ultrasound image velocimetry (u-UIV) to predict HR hemodynamic parameters. Specifically, the Navier–Stokes equations were encoded into the PINN to dynamically optimize the network performance under physical constraints, and a refined mapping network was added at the input to achieve data refinement. During the prediction of HR ultrasound hemodynamic parameters, only the sparse spatial coordinates in the time series were input into the PINN, and the velocity vectors generated from the u-UIV were used together with physical residuals to enhance the physical correctness of HR predictions during the iterative process. Main results. The performance of the refined mapping network was validated via simulations, with a 1.9-fold increase in the radial resolution and a 2.5-fold increase in the axial resolution. HR velocity field estimation from in vitro and in vivo data showed good agreement with theoretical values and u-UIV measurements, with micrometer-level spatial resolution (88 µm

×

115 µm for straight vessel, 75 µm

×

120 µm for stenotic vessel and 63 µm × 79 µm for in vivo data), while the pressure field could be inferred from physical laws. Significance. The proposed method performs well when few data samples are available and has the potential to assist in the clinical diagnosis of vascular diseases.
Isotopologue-selective laser cooling of molecules
Authors: Kogel Felix , Garg Tatsam , Rockenhäuser Marian , Morales-Ramírez Sebastián A , Langen Tim
Published: December 2024

Direct laser cooling of molecules has made significant progress in recent years. However, the selective cooling and manipulation of generic molecular samples based on their isotopic composition, which is ubiquitous in atomic laser cooling, has not yet been achieved. Here, we demonstrate such isotopologue-selective laser cooling and near-arbitrary control over the isotopic composition of a molecular beam, using barium monofluoride (BaF) as an example. The manipulation of the rare and previously uncooled

136

BaF

is achieved in the presence of several isotopologues of significantly higher natural abundance. Our results enable intense molecular beams, high fidelity detection and manipulation of select low-abundance isotopologues or isotopic mixtures. Such beams are a first step towards isotopologue-selective molecular trapping and will be useful for applications in trace gas analysis, cold collisions and precision tests of fundamental symmetries.
The simultaneous ground-state cooling and quantum synchronization of two mechanical oscillators via backward Brillouin scattering
Authors: Chen Shan-Shan , Li Ren-Pu , Zhang Jing-Jing , Guo Yong-Rui , Yang Huan , Zhang Na-Na , Ma Yong
Published: December 2024

The simultaneous ground-state cooling and the quantum synchronization of multiple mechanical oscillators are very important in the study of the quantum coherence of the optomechanical system with multiple mechanical modes. In this paper, we propose a scheme for investigating the simultaneous ground-state cooling and the quantum synchronization of two mechanical oscillators based on an optomechanical system via backward stimulated Brillouin scattering. A photon-phonon interaction via the backward stimulated Brillouin scattering process is introduced in this scheme, which is beneficial for cooling the optomechanical system. It is found that simultaneous ground-state cooling and quantum synchronization of two mechanical oscillators can be achieved when a suitable photon-phonon coupling via the backward stimulated Brillouin scattering process is chosen. Quantum synchronization is enhanced with the help of the photon-phonon coupling via the backward stimulated Brillouin scattering process. In addition, the relation between simultaneous ground-state cooling and quantum synchronization is discussed. It turns out that the appearance of simultaneous ground-state cooling is accompanied by quantum synchronization, but simultaneous ground-state cooling may not be realized when quantum synchronization is achieved. Our scheme paves a new way for the control of the quantum properties of the mechanical oscillators based on optomechanical system.
Realization of two-dimensional beam scanning in 0.2 THz band with the combination of frequency sweeping and phased array method
Authors: Wang Kai , Li Chao , Zheng Shen , Fang Guang-you
Published: December 2024

Based on terahertz (THz) waves, the realization of mobile high-speed communication and rapid high-resolution imaging through two-dimensional (2D) electronically controlled beam scanning antennas holds significant research merit. However, accomplishing 2D electronically controlled beam scanning within the THz band poses formidable challenges. This paper presents a novel design methodology for a 2D beam-scanning antenna specifically tailored for the THz frequency range. Operating effectively within 190 GHz–210 GHz, the proposed antenna demonstrates frequency-controlled beam scanning along one dimension, while leveraging phased array technology to achieve phase-controlled beam scanning in the orthogonal dimension. Based on the proposed concept of combining frequency scanning and phased array to realize 2D beam scanning, the 2D electronically controlled beam scanning in the THz band was be ultimately realized in this paper. This antenna holds pivotal application potential in enhancing the acquisition efficiency of THz imaging field of view, augmenting the capability to capture moving targets, and advancing the development of next-generation mobile communication technologies, notably 6 G.
Optimal control and global dynamics of a fractional-order infectious disease model incorporating vaccination and generalized incidence rate
Authors: Xu Conghui , Yu Yongguang , Guo Ke , Ren Guojian , Lu Zhenzhen , Si Xinhui
Published: December 2024

To investigate the transmission dynamics of infectious diseases driven by highly contagious pathogens, we propose a fractional-order model for infectious disease spread. The model encapsulates the isolation and vaccination measures by delineating the dynamics of isolated and vaccinated populations. The dynamic properties of the model are examined through the establishment of the basic reproduction number R
0. By considering the value of R
0 as a critical threshold, we analyze the global asymptotic stability of both the disease-free equilibrium and the endemic equilibrium within the proposed model. Ultimately, vaccination and isolation measures serve to diminish the number of effective contacts between infected and susceptible individuals, thereby leading to a reduction in the infection rate. Consequently, the control parameters are carefully chosen to modulate the infection rate, leading to the formulation of a corresponding fractional optimal control problem (FOCP). Utilize diverse datasets pertaining to the Corona Virus Disease 2019 (COVID-19) to identify the model parameters. The effectiveness of the proposed model in delineating the transmission dynamics of infectious diseases is corroborated through a comprehensive data fitting analysis. Concurrently, utilizing COVID-19 data, the associated theoretical results are numerically validated. Moreover, the FOCP is numerically addressed under various control strategies, offering theoretical insights for the control and prevention of infectious disease transmission.
Photoelectric characteristic of hybrid thin-film solar cells and metasurface absorbers
Authors: Zhu Jun , Lin Sunlong
Published: December 2024

As the demand for high-efficiency, low-cost solar cells continue to increase, existing thin-film solar cells still face many challenges in terms of light absorption efficiency and charge transport performance. To address these issues, we design and study a PEDOT:PSS/CdTe hybrid thin-film solar cell structure combined with a metasurface absorber layer. We use a metasurface structure with a tetragonal embedded ring resonator pattern in the CdTe absorber layer. This structure can produce a strong electric and magnetic field localization effect on the surface of the absorption layer, improving the light absorption rate of the battery. At the same time, the introduction of organic polymer materials (PEDOT: PSS) optimizes the electrode interface quality and reduces the interface defects and composite losses between materials, and further improves the photoelectric conversion efficiency (PCE) of the battery. we introduce traditional absorption enhancement methods (titanium nanoparticle arrays and pyramid TiO2 arrays) to this structure. The solar cell proposed has a spectral response rate of 96.71% and its PCE reaches 35.66%. The research indicates that the new structure holds significant potential for the application of high-efficiency solar cells, offering new ideas for the design and manufacture of solar cells in the future.