bluuebunny/crossref_metadata_2025 huggingface dataset:
Dissolved Nitrogen Cycling in the Eastern Canadian Arctic Archipelago and Baffin Bay From Stable Isotopic Data
Authors: Westbrook H. C. , Bourbonnais A. , Manning C. C. M. , Tremblay J.‐É. , Ahmed M. M. M. , Else B. , Granger J.
Published: December 2024

Climate change is expected to alter the input of nitrogen (N) sources in the Eastern Canadian Arctic Archipelago and Baffin Bay due to increased discharge from glacial meltwater and permafrost thaw. Since dissolved inorganic N is generally depleted in surface waters, dissolved organic N (DON) could represent a significant N source fueling phytoplankton activity in Arctic ecosystems. Yet, few DON data for this region exist. We measured concentrations and stable isotope ratios of DON (δ15N) and nitrate (NO3−; δ15N and δ18O) to investigate the sources and cycling of dissolved nitrogen in regional rivers and marine samples collected in the Eastern Canadian Arctic Archipelago and Baffin Bay during the summer of 2019. The isotopic signatures of NO3− in rivers could be reproduced in a steady state isotopic model by invoking mixing between atmospheric NO3− and nitrified ammonium as well as NO3− assimilation by phytoplankton. DON concentrations were low in most rivers (≤4.9 μmol N L−1), whereas the concentrations (0.54–12 μmol N L−1) and δ15N of DON (−0.71–9.6‰) at the sea surface were variable among stations, suggesting dynamic cycling and/or distinctive sources. In two regions with high chlorophyll‐a, DON concentrations were inversely correlated with chlorophyll‐a and the δ15N of DON, suggesting net DON consumption in localized phytoplankton blooms. We derived an isotope effect of 6.9‰ for DON consumption. Our data helps establish a baseline to assess future changes in the nutrient regime for this climate‐sensitive region.
Segregation‐Induced Flow Transitions in Rock‐Ice Mixtures: Implications for Rock‐Ice Avalanche Dynamics
Authors: Zhou Gordon G. D. , Cui Kahlil F. E. , Jing Lu , Mangeney Anne , Cui Yifei , Huang Yu , Chen Xiaoqing
Published: December 2024

Global climate change has been intensifying the scale and frequency of rock‐ice avalanches and similar catastrophic mass movements in high‐mountain regions. The difference in the physical characteristics of rock and ice particles leads to mixing and segregation during flow. Although, both particle segregation and the presence of ice fundamentally alter flow behavior, the joint influence and feedback of these two aspects are overlooked in state‐of‐the‐art rock‐ice avalanche models. Using discrete element simulations, we show that by controlling the distribution of inter‐particle frictional interactions within the mixture, segregation patterns resulting from the size, density, concentration, and surface friction differences of rock and ice phases can induce sharp velocity gradients along the flowing thickness. Flowing layers where low friction contacts with ice are abundant tend to flow faster and can induce slow creeping motion in an otherwise static basal layer dominated by more frictional rocks. Based on these observations, we find that the effective friction of rock‐ice flows for various mixture concentrations and size ratios can be obtained as a sum of the single‐phase rheologies of rocks and ice weighted according to their microscopic contact probabilities. This effective friction for rock‐ice mixtures allows us to extend a recent non‐local granular fluidity framework that captures the complex segregation‐flow feedback mechanism in rock‐ice flows. The findings provide a deeper micromechanical understanding of how particle interactions influence rock‐ice avalanche mobility, which ultimately improves flow models needed for hazard assessment and mitigation.
Epidemiology, treatment and outcomes of gastroenteropancreatic neuroendocrine neoplasms
Authors: Uhlig Johannes , Nie James , Gibson Joanna , Cecchini Michael , Stein Stacey , Lacy Jill , Kunz Pamela , Kim Hyun S.
Published: December 2024

To investigate incidence, treatment patterns and outcomes of gastroenteropancreatic neuroendocrine neoplasms (GEP-NEN) in the United States. The 2019 National Cancer Database was searched for adult GEP-NEN patients. Main outcomes included overall and site-specific incidence, treatment patterns, and overall survival (OS). Overall survival was evaluated using averaged Cox regression. 86,324 GEP-NEN patients were included (6.33% of all GEP malignancies). From 2004 to 2016, annual GEP-NEN cases increased (n = 4,010 to n = 9,379), largely driven by low-stage, low-grade disease. Most patients received surgery, either alone (72.9%) or in combination with systemic therapy (4.9%). Longest overall survival (OS) was evident in patients with low stage and low grade GEP-NEN of the small intestine and rectum (p < 0.001). Patients undergoing surgical resection demonstrated longest OS. The addition of systemic therapy was most effective in high stage G3 NEN. Having higher income (≥$63,333) and private insurance or Medicare, but not Medicaid, was associated with improved survival. GEP-NEN incidence increases, likely due to improved detection and diagnosis. Treatment patterns have evolved to follow the latest international guidelines and site-specific improvement in survival is noted. In addition to disease specific factors, insurance access and socioeconomic factors emerged as potential targets for improving outcomes.
Proximity hybridization-triggered cascade amplification for label-free SERS detection of Alzheimer's amyloid-β oligomers
Authors: Luo Qisheng , Kang Xin , Zhang Chunyuan , Zhang He , Huang Yongning , Tang Qianli , Liao Xianjiu , Gao Fenglei , Liu Zhao
Published: December 2024

Most of the existing SERS systems failed to achieve satisfactory results in early diagnosis of Alzheimer's disease owing to a lack of effective signal transduction.
An effective method for detecting nitrous oxide using alkaline washing and GC-MS
Authors: Yang Mu , Gao Wenqing , Ma Liang , Chen Xingyu , Wang Haixing , Yu Jiancheng , Tang Keqi
Published: December 2024

An effective method for detecting nitrous oxide using alkaline washing and GC-MS was developed to eliminate CO2 from gas samples, solving the N2O and CO2 co-elution issue in GC-MS analysis without the need for specialized equipment or columns.
Correction: Fabrication of yeast β-glucan/sodium alginate/γ-polyglutamic acid composite particles for hemostasis and wound healing
Authors: Zou Qinglin , Duan Hongdong , Fang Shimin , Sheng Wenlong , Li Xiaobin , Stoika Rostyslav , Finiuk Nataliya , Panchuk Rostyslav , Liu Kechun , Wang Lizhen
Published: December 2024

Correction for ‘Fabrication of yeast β-glucan/sodium alginate/γ-polyglutamic acid composite particles for hemostasis and wound healing’ by Qinglin Zou et al., Biomater. Sci., 2024, 12, 2394–2407, https://doi.org/10.1039/d3bm02068a.
Tröger's base-embedded macrocycles with chirality
Authors: Shi Conghao , Xu Guangzhou , Qiu Heng , Li Yumei , Lu Xiancai , Jiang Juli , Wang Leyong
Published: December 2024

TB-embedded macrocycles are highlighted, focusing on the linkers of these macrocycles and the correlation between the properties of TB and TB-embedded macrocycles. TB-embedded macrocycles, consisting of (1) TB-based covalent macrocycles and (2) TB-based metal–organic macrocycles are discussed.
Simple bifunctional salts for synthesising block copolymers from anhydrides/epoxides and vinyl acetate
Authors: Lykkeberg Anna , Garden Jennifer A.
Published: December 2024

The synthesis of poly(ester-block-vinyl acetate) was achieved using a robust xanthate reagent with dual activity for two distinct polymerisation mechanisms.
Advancements in flexible biomechanical energy harvesting for smart health applications
Authors: Wang Yuxiao , Sun Mengdie , Kwon Sun Hwa , Dong Lin
Published: December 2024

This review delves into the convergence of flexible biomechanical energy harvesting technologies, highlighting their transformative potential in the rapidly evolving field of smart health.
Continuous activation of phenoxide and CF3I for multiple trifluoromethylations
Authors: Nakashima Yusei , Kusano Shinjiro , Inishi Tsukasa , Nitta Yasuyuki , Nishikata Takashi
Published: December 2024

Visible light-promoted multiple trifluoromethylation of phenols using CF3I enables sequential CF3 group introduction via a novel continuous activation strategy, providing access to multi-CF3-substituted phenols under mild conditions.
Self-assembly of cationic surfactant in choline chloride-based deep eutectic solvents: structural solvation and dynamics
Authors: Vora Yagnik , Sethi Omish , Bariya Sanjay N. , Gawali Santosh L. , Soni Saurabh S. , Kang Tejwant Singh , Hassan Puthusserickal A. , Kuperkar Ketan
Published: December 2024

Physicochemical characterization of choline chloride-based deep eutectic solvents (DESs) corroborated with the computational simulation approach.
Viedma deracemization mechanisms in self-assembly processes
Authors: Ribó Josep M. , Hochberg David , Buhse Thomas , Micheau Jean-Claude
Published: December 2024

Simulations on an ODE-based model shows that there are many common points between Viedma deracemization and chiral self-assemblies of achiral building blocks towards chiral nanoparticles.
Length-dependent water permeation through a graphene channel
Authors: Wang Zi , Li Shuang , Gao Shiwu , Su Jiaye
Published: December 2024

Water confined in two-dimensional channels exhibits unique properties, such as rich morphology, specific phase transition and a low dielectric constant.
Ferroelastic phase transition-modulated electronic transport and photoelectric properties in monolayer 1T′ ZrCl2
Authors: Xu Yuehua , Sun He , Chen Jindian , Long Qianqian , Xu Haowen
Published: December 2024

Ferroelasticity in monolayer ZrCl2 with a 120° lattice rotation facilitates diverse electronic transport and photoresponse switching between the O1 and O3 variants.
The contribution of digital and sensing technologies and big data towards sustainable food supply and value chains
Authors: Cozzolino Daniel
Published: December 2024

Modern digital and sensing technologies enable agile and modern food supply and value chains.
Direct synthesis of 2-pyrone-4,6-dicarboxylic acid and trans-aconitic acid from renewable gallic acid and tannic acid
Authors: Moeller Finn , Waldvogel Siegfried R.
Published: December 2024

Gallic acid and tannins originate from underutilized renewable bark which can be directly converted to 2-pyrone-4,6-dicarboxylic acid by oxidation with perborate.
Metal-free stereoselective intramolecular oxyamination of alkynes using a robotic and rapid photocatalytic synthesis and screening system
Authors: Lu Jia-Min , Mao Yihui , Guo Qihang , Zhong Chengcheng , Gao Xian-Ge , Fang Qun , Lu Zhan
Published: December 2024

Utilizing a robotic visible-light photocatalytic system, we realized a metal-free and 100% atom-economical method for the difunctionalization of alkynes with high stereoselectivity and regioselectivity.
Macromolecular electrolyte engineering for tuning Zn-ion solvation chemistry and boosting H+ storage toward stable aqueous zinc-organic batteries
Authors: Cheng Linqi , Li Mengfan , Zhang Xupeng , Wang Wanting , Zhao Lina , Wang Heng-Guo
Published: December 2024

We demonstrate a macromolecular electrolyte engineering strategy to break the Zn2+ solvation sheath using a porphyrin-based additive, which can facilitate the formation of the Zn-porphyrin complex and achieve superior electrochemical performance.
An agarose fluidic chip for high-throughput in toto organoid imaging
Authors: De Beuckeleer Sarah , Vanhooydonck Andres , Van Den Daele Johanna , Van De Looverbosch Tim , Asselbergh Bob , Kim Hera , Campsteijn Coen , Ponsaerts Peter , Watts Regan , De Vos Winnok H.
Published: December 2024

Cell and developmental biology increasingly relies on tissue mimics such as organoids. We developed and validated a fluidic chip for high-throughput, complete visualization of these models in their intact state using light-sheet microscopy.
Smart drug delivery: a DFT study of C24 fullerene and doped analogs for pyrazinamide
Authors: Moumivand Azam , Naderi Fereshteh , Moradi Omid , Makiabadi Batoul
Published: December 2024

The potential applicability of the C24 nanocage and its boron nitride-doped analogs (C18B3N3 and C12B6N6) as pyrazinamide (PA) carriers was investigated using density functional theory.
Three-dimensional iron–cobalt phosphide nanosheets on nickel oxide nanoparticles for improved glucose oxidation reaction
Authors: Marimuthu Sundaramoorthy , Anoopkumar Harichandana , Maduraiveeran Govindhan
Published: December 2024

Herein, we demonstrate heterostructured three-dimensional iron–cobalt phosphide nanosheets on nickel oxide nanoparticles for enhanced glucose oxidation reaction under an alkaline electrolyte.
Keggin type dilacunary phosphotungstate anchored to different acidic supports: design, characterization and its catalytic evaluation for the synthesis of fuel additives with kinetic study
Authors: Patel Anjali , Joshi Margi
Published: December 2024

A novel approach for the efficient synthesis of n-butyl levulinate via the development of inorganic materials, PW10/ZHY and PW10/ZrO2.
Advances in precise synthesis of metal nanoclusters and their applications in electrochemical biosensing of disease biomarkers
Authors: Han Ying , Zhang Ping , Duan Xiaoyi , Gao Xueyun , Gao Liang
Published: December 2024

Metal nanoclusters as advanced electrode materials to achieve electrochemical biosensing of diverse disease-associated biomarkers.
Selenium-assisted copper-catalyzed synthesis of phosphoramide from secondary phosphine oxide involving the construction of N–P bonds
Authors: Wang Zhenzhen , Huang Lihua , Huang Rui , Wang Juan , Cheng Chunru
Published: December 2024

A new, simpler and higher-yield pathway for obtaining phosphoramides has been developed.
NIR AIE luminogens for primary and metastasis tumor imaging and tracking applications
Authors: Zhu Yujiao , Zeng Yuhang , Liu Huimin , Yin Yuting , Chen Bin , Hu Rong
Published: December 2024

Modern lifestyle changes, including irregular diets and late-night activities, have contributed to a significant rise in cancer rates, particularly among younger demographics, highlighting the pressing need for early detection and treatment.
Thermogelation of nanoemulsions stabilized by a commercial pea protein isolate: high-pressure homogenization defines gel strength
Authors: Renggli Damian , Doyle Patrick S.
Published: December 2024

Structure formation by colloidal thermogelation of a complex plant-based nanoemulsion system stabilized by a commercial pea protein isolate.
Residual based tilt tri‐rotor UAV actuator fault detection using TSK fuzzy model
Authors: He Guang , Bao Yi , Xin Liang , Long Zhiqiang
Published: December 2024

Undetected actuator faults on tilt tri‐rotor UAVs can lead to system failures and uncontrolled crashes. Multiple flight modes result in complex models with strong nonlinearity, making fault detection of their actuators a very challenging task. To address this issue, this article proposes a fault detection method based on residual generated by using TSK fuzzy model. Initially, the flight modes of the tilt tri‐rotor UAV are modeled as the TSK fuzzy model. Following this, the residual generator is employed for rapid detection of actuator failures. To enhance detection accuracy, the kernel principal component analysis (KPCA) algorithm is used for a secondary confirmation. The proposed algorithm was validated using both a simulation platform and real flight data. The results demonstrate that the fault detection algorithm achieves high accuracy and real‐time performance, with a computing time of approximately 41 ms in real controller hardware, thus meeting the requirements of practical applications.
Analysis and calculation of electromagnetic force of stator winding and damping bar during dynamic loading of pumped storage generator/motor
Authors: Tao Dajun , Dai Xu , Ge Baojun , Li Guifen , Hu Gang
Published: December 2024

Frequently and rapidly dynamic conversion is one of the main differences between pumped‐storage motor and general hydro‐generator. In the process of changing operating conditions, in order to achieve fast dynamic conversion, the loading rate requirement of pumped storage motors is often much higher than that of conventional generators, which brings great impact on the key structural components of generators, it affects the safe operating life of motors directly. To solve the impact of dynamic loading rate on key structural components of pumped storage motors, for a pumped storage motor as an example, investigating different loading rates during the dynamic conversion of two main operating conditions on pumped storage motors (power generation and electric power) of pumped storage motors are investigated. Calculating accurately the distribution laws of electromagnetic forces of key structural components which contains stator tooth walls and damping strips during dynamic loading. The results show that the different loading rates will affect the force distribution of the key position directly, under the condition of generator state and motor state, the distribution of force on stator winding and damping bar present different laws, it will provide reference for the determination of multi‐state conversion loading rate of pumped storage motor and the improvement of pumped storage motor structure scheme.
An efficient no‐reference image quality analysis based on statistical perceptual features
Authors: Al Sameera B. N. , Gaidhane Vilas H.
Published: December 2024

It is well known that image quality needs to be measured with human perception in many computer vision applications. However, these approaches are expensive and require more time for image quality analysis. Therefore, this paper proposes a robust and computationally efficient objective‐mathematical model based on statistical perceptual features. The structural and textural features are computed using the modified regularized heaviside local binary pattern (RH‐LBP) approach and the concept of entropy. The higher‐order probability coefficients of images are considered to extract features that are highly correlated to the human visual system features. Further, the additivity property of Renyi entropy is used to show the randomness of the information combining two terms: One extracts the images spatial intensity changes, and therefore their texture qualities, and the other attain structural details. The features in the proposed approach are jointly optimized to achieve better robustness, monotonicity and match human assessments on image quality, while minimizing the computational complexity and run time. Experiments are conducted with three synthetically distorted datasets, KonIQ‐10K, BIQ2021, and LIVE (wild), and two intentionally distorted datasets, TID2013 and CSIQ and are used to evaluate performance index. The proposed method offers competitive performance compared with state‐of‐the‐art methods.
Deep learning‐based barrier‐function super‐twisting sliding mode control for integrating renewables in smart grid
Authors: Armghan Hammad , Xu Yinliang , Xue Yixun , Ali Naghmash
Published: December 2024

This study presents a two‐step controller design for integrating wind and photovoltaic energy systems into the smart grid. In the first stage, an enhanced deep neural network (DNN), optimised by particle swarm optimisation and a genetic algorithm, is employed to generate maximum power point (MPP) targets for both wind and solar systems. The DNN incorporates advanced features like hyperparameter tuning, softmax attention, dropout, and early stopping to improve prediction accuracy and prevent overfitting. In the second stage, a barrier‐function‐based adaptive super‐twisting sliding mode controller is developed to track the MPP and maintain stable DC bus voltage. This controller effectively reduces chattering and operates without requiring detailed knowledge of disturbance limits. The proposed design aims to maximise power extraction, ensure DC bus voltage stability, and enable smooth power delivery to the grid. MATLAB simulations and real‐time hardware testing validate the controller's performance, demonstrating significant improvements over traditional methods.
Variability in hot sub-luminous stars and binaries: Machine-learning analysis of Gaia DR3 multi-epoch photometry
Authors: Ranaivomanana P. , Uzundag M. , Johnston C. , Groot P.J. , Kupfer T. , Aerts C.
Published: December 2024

Hot sub-luminous stars represent a population of stripped and evolved red giants that is located on the extreme horizontal branch. Since they exhibit a wide range of variability due to pulsations or binary interactions, it is crucial to unveil their intrinsic and extrinsic variability to understand the physical processes of their formation. In the Hertzsprung-Russell diagram, they overlap with interacting binaries such as cataclysmic variables (CVs). By leveraging the most recent clustering algorithm tools, we investigate the variability of 1,576 candidate hot subdwarf variables using comprehensive data from Gaia DR3 multi-epoch photometry and Transiting Exoplanet Survey Satellite (TESS) observations. We present a novel approach that uses the t-distributed stochastic neighbour embedding and the uniform manifold approximation and
projection dimensionality reduction algorithms to facilitate the identification and classification of different populations of variable hot subdwarfs and CVs in a large dataset. In addition to the publicly available Gaia time-series statistics table, we adopted additional statistical features that enhanced the performance of the algorithms. The clustering results led to the identification of 85 new hot subdwarf variables based on Gaia and TESS light curves and of 108 new variables based on Gaia light curves alone, including reflection-effect systems, HW Vir, ellipsoidal variables, and high-amplitude pulsating variables. A significant number of known CVs (140) distinctively cluster in the 2D feature space among an additional 152 objects that we consider candidates for new CVs. This study paves the way for more efficient and comprehensive analyses of stellar variability from ground- and space-based observations, and for the application of machine-learning classifications of candidate variable stars in large surveys.
Not just PAH3.3: Why galaxies turn red in the near-infrared
Authors: Vulcani Benedetta , Treu Tommaso , Malkan Matthew , Lai Thomas S.-Y. , Calabrò Antonello , Castellano Marco , Napolitano Lorenzo , Mascia Sara , Poggianti Bianca M. , Santini Paola , Fritz Jacopo , Metha Benjamin , Yoon Ilsang , Wang Xin
Published: December 2024

We measured the spectral properties of a sample of 20 galaxies at z ∼ 0.35 selected for having surprisingly red JWST/NIRCAM F200W-F444W colors. Of these, 19 galaxies were observed with JWST/NIRSpec in the PRISM configuration, while the remaining galaxy was observed with the high-resolution gratings. Of the 20 galaxies in our sample, 17 exhibit strong 3.3 μm polycyclic aromatic hydrocarbon (PAH) emission (equivalent width (EW) (PAH3.3) ≥ 0.03 μm). In these galaxies, the strength of the color excess does not depend on environment and correlates with EW(PAH3.3). Nonetheless, the presence of the PAH3.3 alone cannot fully explain the color excess, as an EW of ∼0.1 μm is able to increase the color of galaxies by only 0.13 mag. A contribution from a hot dust component is required to explain the excess. Both the PAH3.3 EW and flux correlate with the Hα EW and flux, suggesting that they are produced by the same mechanism. Five of the galaxies of our sample showing PAH3.3 would be classified as passive based on broadband rest frame colors ((B-V) and/or UVJ diagrams) and are hence “faux passive”. Of these, three galaxies have a significantly lower EW(PAH3.3) given their color and also have low EW(Hα), and we tentatively conclude that this behavior is due to the presence of an active galactic nucleus. The three galaxies with no PAH3.3 in emission have passive spectra, as do the eight galaxies in our sample with normal F200W-F444W colors. We therefore conclude that the PAH3.3 feature is linked to dust-enshrouded star formation. The dust-corrected star formation rate (SFR) from PAH3.3 is a factor of 3.5 higher than the SFR obtained from Hα, suggesting that these galaxies are characterized by significant amounts of dust.
Food preferences of fish in integrated multi-trophic aquaculture freshwater ponds based on fatty acids and stable isotopes
Authors: Nahon Sarah , Jaeger Christophe , Menniti Christophe , Roucaute Marc , Kerhervé Philippe , Mortillaro Jean-Michel , Aubin Joël
Published: December 2024

Integrated multi-trophic aquaculture (IMTA) is a solution to biomitigate waste by rearing species from different trophic levels. In European freshwater fishponds, common carp is often produced along with secondary fish species. Developing recycling IMTA systems requires better understanding of the complexity of trophic interactions between fish. Analyses of fatty acid and stable isotopes of carbon and nitrogen are suitable tools for determining food preferences of fish species. Three IMTA systems, including carp, roach, rudd and perch, were investigated in ponds: a semi-intensive (SI) pond in which fish were fed pellets; a semi-intensive pond in which fish were fed pellets, coupled with a lagoon planted with macrophytes (SIC); and an extensive (E) pond in which fish were not fed pellets. In the SI and SIC ponds, fatty acid profiles of carp, roach and rudd were closed to those of pellets. The δ13C and δ15N values of fish confirmed that they mainly fed on pellets, but the diet of roach and rudd also contained natural food sources. In the E ponds, fatty acid profiles of carp, roach and rudd slightly differed but their δ13C and δ15N values were similar. Mixing model indicated that fish from E ponds mainly fed on zooplankton. Regardless of the IMTA systems, fatty acid and stable isotope analyses indicated that juveniles consumed mainly large zooplankton. In the three systems, the FA profile of perch was closed to that of juvenile fish. Mixing model estimated that perch supplemented their diet with large zooplankton and crayfish. In the SI and SIC ponds, the distribution of commercial pellets drove the trophic interactions among fish. In the E ponds, fish had significant feeding overlap due to the limited resources available.
2.12 Industrial Applications of Fluorine Chemistry in Plasma Etch Gases
Authors: Kirsch P.
Published: December 2024

Reactive ion etching is a key technology in the production of advanced semiconductor devices with a resolution of down to sub-10-nm scales. Depending on the exact application, NF3, SF6 as well as complex fluoro(hydro)carbons are used to generate a plasma consisting of ions and other reactive species which converts silicon and its derivatives into volatile compounds. Recently, the development objectives of new etch gases have moved from pure performance to a more complex set of properties including low global warming potential (GWP) and compliance with regulation on fluoroorganic compounds (PFAS). The structure of fluorinated etch gases with low GWP incorporates chemically "weak spots" facilitating atmospheric degradation. The fragmentation in the energetic plasma environment can be predicted by computational methods, enabling the optimization of the ion composition for high etch rate or selectivity between different materials.
On the Schrödinger–Bopp–Podolsky system: Ground state and least energy nodal solutions with nonsmooth nonlinearity
Authors: Bahrouni Anouar , Missaoui Hlel
Published: December 2024

In this paper, we investigate a new class of Schrödinger–Bopp–Podolsky systems. Using minimization techniques and the concept of generalized subdifferentials, we establish the existence of a ground state solution with a fixed sign as well as a least energy nodal solution for the system. Furthermore, we demonstrate that the energy of the nodal solution is precisely twice that of the ground state solution.
Particle transport in open polygonal billiards: A scattering map
Authors: Orchard Jordan , Frascoli Federico , Rondoni Lamberto , Mejía-Monasterio Carlos
Published: December 2024

Polygonal billiards exhibit a rich and complex dynamical behavior. In recent years, polygonal billiards have attracted much attention due to their application in the understanding of anomalous transport, but also at the fundamental level, due to their connections with diverse fields in mathematics. We explore this complexity and its consequences on the properties of particle transport in infinitely long channels made of the repetitions of an elementary open polygonal cell. Borrowing ideas from the Zemlyakov–Katok construction, we construct an interval exchange transformation classified by the singular directions of the discontinuities of the billiard flow over the translation surface associated with the elementary cell. From this, we derive an exact expression of a scattering map of the cell connecting the outgoing flow of trajectories with the unconstrained incoming flow. The scattering map is defined over a partition of the coordinate space, characterized by different families of trajectories. Furthermore, we obtain an analytical expression for the average speed of propagation of ballistic modes, describing with high accuracy the speed of propagation of ballistic fronts appearing in the tails of the distribution of the particle displacement. The symbolic hierarchy of the trajectories forming these ballistic fronts is also discussed.
Effects of grain boundary phases on recoil loops by in situ observation of magnetization behavior in nanocrystalline PrNd–Fe–B magnets
Authors: Xiao Yao , Li Jun , Wang Renquan , Wang Lu , Liu Chang , Liu Ying
Published: December 2024

The grain boundary phase (GBP) has a significant influence on the magnetization behavior in nanocrystalline PrNd–Fe–B magnets. The current study demonstrates that reversible/irreversible magnetization behavior and the phenomenon of open recoil loops are related to both the nature of GBPs and the magnetization state by in situ observation. The optimization of GBPs nature (increase the volume fraction and improve the composition of GBPs) leads to the suppression of reversible magnetization behavior and the phenomenon of open recoil loops at low fields. Since the asymmetric magnetic domain structure appears only at low cycle fields, the openness phenomenon originates from the weak pinning grain boundaries (GBs). In addition, optimization of the GBPs also enhances pinning strength and uniformity, which contributes to the domain walls being pinned in the GBs at higher external fields. At this moment, the domain wall is dominated by irreversible magnetization behavior, and the openness phenomenon disappears. This proves that the coercivity mechanism is transformed from inhomogeneously weak pinning to homogeneously strong pinning with the optimization of GBPs. Consequently, the coercivity and squareness factor are significantly enhanced. This study sheds light on the understanding of the effects of GBP's nature on recoil loops and coercivity mechanism, and it also provides significant guidance for the development of advanced permanent magnets.
Electronic and optical properties of a Ta2NiSe5 monolayer: A first-principles study
Authors: Guo Miaomiao , Li Yuanchang
Published: December 2024

The crystal structure, stability, electronic, and optical properties of the Ta2NiSe5 monolayer have been investigated using first-principles calculations in combination with the Bethe–Salpeter equation. The results show that it is feasible to directly exfoliate a Ta2NiSe5 monolayer from the low-temperature monoclinic phase. The monolayer is stable and behaves as a normal narrow-gap semiconductor with neither spontaneous excitons nor non-trivial topology. Despite the quasi-particle and optical gaps of only 266 and 200 meV, respectively, its optically active exciton has a binding energy up to 66 meV and can exist at room temperature. This makes it valuable for applications in infrared photodetection, especially its inherent in-plane anisotropy adds to its value in polarization sensing. It is also found that the inclusion of spin–orbit coupling is theoretically necessary to properly elucidate the optical and excitonic properties of a monolayer.
Neural-network enabled octave-spanning coherent diffraction imaging
Authors: Li Boyang , Xiao Zehua , Yuan Hao , Xue Bing , Cao Huabao , Wang Hushan , Zhao Wei , Fu Yuxi
Published: December 2024

Ultrafast lasers, providing the shortest pulses worldwide, have been playing a vital role in the ultrafast imaging technology. The temporal resolution has been increasing rapidly in recent years but finally reaches its limit—the pulse width approaches photoperiods, causing significant broadening of spectral bandwidth. The state-of-the-art high harmonics generation based attosecond lasers, with pulse widths reaching ∼50 attoseconds, present octave-spanning spectra. This brings a major challenge to traditional imaging methods, as they result in unbearable chromatic aberrations. To address this challenge, we propose the neural-network approach for broadband imaging and demonstrate its effectiveness empirically by facilitating rapid coherent diffractive imaging under octave-spanning supercontinuum illumination. The proposed method remains effective when deployed with three-octave-spanning spectra, supporting both continuous and comb-like profiles as indicated by simulations. Such lensless imaging method, applicable to both extreme ultraviolet and soft x-ray sources, potentially provides an approach to attosecond imaging.
Simultaneous study of acoustic and optic phonon scattering of electrons and holes in undoped GaAs/AlxGa1−xAs heterostructures
Authors: Ashlea Alava Y. , Kumar K. , Harsas C. , Mehta P. , Hathi P. , Chen C. , Ritchie D. A. , Hamilton A. R.
Published: December 2024

The study of phonon coupling in doped semiconductors via electrical transport measurements is challenging due to unwanted temperature-induced effects such as dopant ionization and parallel conduction. Here, we study phonon scattering in 2D electrons and holes in the 1.6–92.5 K range without the use of extrinsic doping, where both acoustic and longitudinal optic (LO) phonons come into effect. We use undoped GaAs/AlxGa1−xAs heterostructures and examine the temperature dependence of the sample resistivity, extracting phonon coupling constants and the LO activation energy. Our results are consistent with results obtained through approaches other than transport measurements and highlight the benefit of this approach for studying electron–phonon and hole–phonon coupling.
Generalized synchronization in the presence of dynamical noise and its detection via recurrent neural networks
Authors: Amigó José M. , Dale Roberto , King Juan C. , Lehnertz Klaus
Published: December 2024

Given two unidirectionally coupled nonlinear systems, we speak of generalized synchronization when the responder “follows” the driver. Mathematically, this situation is implemented by a map from the driver state space to the responder state space termed the synchronization map. In nonlinear times series analysis, the framework of the present work, the existence of the synchronization map amounts to the invertibility of the so-called cross map, which is a continuous map that exists in the reconstructed state spaces for typical time-delay embeddings. The cross map plays a central role in some techniques to detect functional dependencies between time series. In this paper, we study the changes in the “noiseless scenario” just described when noise is present in the driver, a more realistic situation that we call the “noisy scenario.” Noise will be modeled using a family of driving dynamics indexed by a finite number of parameters, which is sufficiently general for practical purposes. In this approach, it turns out that the cross and synchronization maps can be extended to the noisy scenario as families of maps that depend on the noise parameters, and only for “generic” driver states in the case of the cross map. To reveal generalized synchronization in both the noiseless and noisy scenarios, we check the existence of synchronization maps of higher periods (introduced in this paper) using recurrent neural networks and predictability. The results obtained with synthetic and real-world data demonstrate the capability of our method.
In-plane exchange field enhanced anomalous Andreev reflection in graphene-based ferromagnet/superconductor junctions
Authors: Tan Chuan , Wu Qingping , Li Haoran , Liu Zhengfang , Xiao Xianbo
Published: December 2024

The study focused on investigating spin transport in a graphene-based ferromagnet/in-plane exchange field/superconductor junction. It was demonstrated that both the spin-flipped reflection and the anomalous Andreev reflection occur in the junction due to the spin-mixing effect induced by the in-plane exchange field in graphene. The research highlighted that increasing the Fermi energy in the junction can lead to a high level of anomalous Andreev reflection. Furthermore, the study also examined the charge conductance and spin-polarized conductance, showing that these properties are influenced by the strength of the vertical exchange field, the in-plane exchange field, and Fermi energy. The findings of this research could potentially open up new avenues for utilizing graphene in spintronics applications.
A study on martensitic transformation behavior in shape memory alloys via a modulated differential scanning calorimetry technique
Authors: Ma Siyao , Zhang Xuexi , Zheng Guangping , Qian Mingfang , Geng Lin
Published: December 2024

Highly precise and efficient characterization of thermophysical parameters associated with martensitic transformation (MT) in shape memory alloys (SMA) is challenging based on conventional calorimetry methods. Moreover, existing methods for evaluating the elastocaloric effect of SMA typically require a series of tests and calculations. In addition, the present method cannot evaluate the nonreversible part during MT. This work proposed a technique rarely mentioned in previous studies on martensitic transformation of metals and alloys, i.e., utilizing the modulated differential scanning calorimetry (MDSC) to superimpose a sinusoidal signal over an underlying DSC ramp. By adjusting appropriate measurement parameters, the reversible and nonreversible parts of thermal events during MT of SMAs were revealed. Furthermore, a series of thermal parameters useful for the study of MT can be obtained by this method and thus may provide a perspective for studying the MT process. Based on MDSC technique, we took Ni-Mn-Sn-(Cu) alloys, a kind of ferromagnetic shape memory alloy, as an example to demonstrate the study of the MT process as well as the elastocaloric effect. From the perspective of energy dissipation, we analyzed the intrinsic relationship between nonreversible component and thermal hysteresis in the MT process. Conventional DSC test and experimental results on the adiabatic temperature change (ΔTad) were also provided to verify the MDSC prediction results.
Ten-moment fluid model for low-temperature magnetized plasmas
Authors: Kuldinow Derek Amur , Yamashita Yusuke , Hara Kentaro
Published: December 2024

In this paper, a one-dimensional 10-moment multi-fluid plasma model is developed and applied to low-temperature magnetized plasmas. The 10-moment model solves for six anisotropic pressure terms, in addition to density and three components of fluid momentum, which allows the model to capture finite kinetic effects. The results are benchmarked against a 5-moment model, which assumes that the gas constituents follow a Maxwellian velocity distribution function (VDF), and a particle-in-cell Monte Carlo collision model that allows for arbitrary non-Maxwellian VDFs. The models are compared in a one-dimensional, low-temperature, partially magnetized plasma test case. The 10-moment results accurately reproduce the anisotropic temperature profile in low-temperature magnetized plasmas, where shear gradients exist due to the E×B drift. We discuss the mechanisms by which the anisotropic pressure can be generated in low-temperature magnetized plasmas. In addition, the importance of a self-consistent heat flux closure to the 10-moment model is studied, showing consistency with other models only when the assumptions of the underlying model are met. The 10-moment model allows for study of electron inertia effects and non-Maxwellian VDFs without the need for kinetic methods that are more computationally expensive.
Effects of streak structure in oblique resonance on the instability in supersonic plate boundary layers
Authors: Li Weitong , Huang Zhangfeng , Liu Jianxin
Published: December 2024

Streaks are large-scale coherent structures in flows and play an important role in the laminar–turbulent transition. In this paper, the effect of streaks in oblique resonance on the instabilities of the first mode with the same spanwise wavenumber as the streaks is investigated. The streaks are obtained by the nonlinear parabolized stability equations, and the instability is analyzed by the bi-global analysis tool. Streaks can be decomposed into the two-dimensional mean-flow distortion (MFD) and the three-dimensional streak modes (SMs). For odd modes, the effects of the MFD dominate, stabilizing low-frequency waves and destabilizing high-frequency waves at small streak amplitudes. While the opposite effects of the SMs dominate at large streak amplitudes. Even modes show similar responses, except for the stabilization of low-frequency waves. The results of the global energy balance indicate that the more negative work of pressure-dilatation terms is responsible for the stabilization of the high-frequency waves compared to low-frequency waves at large streak amplitudes. Due to the stronger concentration of streamwise velocity distribution and the more negative Reynolds stress work in the spanwise direction, the even modes are more stabilized compared to the odd modes. Additionally, streaks can modify the distribution of the Fourier components of the even mode pressure in the spanwise direction; thus, they can induce the spontaneous excitation of a radiating component to the far field.
Midwave infrared resonant cavity detectors with >70% quantum efficiency
Authors: Jackson E. M. , Kim C. S. , Kim M. , Canedy C. L. , Juarez X. G. , Ellis C. T. , Nolde J. A. , Aifer E. H. , Iversen C. , Burgner C. , Kolasa B. , Vurgaftman I. , Jayaraman V. , Meyer J. R.
Published: December 2024

We report resonant cavity infrared detectors with a peak wavelength of 4.54–4.58 μm that combine external quantum efficiency (EQE) exceeding 70% with spectral bandwidth 20–40 nm and ≤2% EQE at all non-resonance wavelengths between 4 and 5 μm. A 300-nm-thick absorber assures that most of the radiation propagating in the cavity produces photocurrent rather than parasitic loss. The cavity is formed by heterogeneously bonding a midwave infrared (MWIR) nBn detector chip to a GaAs/AlGaAs distributed Bragg reflector, etching away the GaSb substrate, forming mesas with diameter ≈100 μm, depositing a Ge spacer, and then depositing a single-period Ge-SiO2 top mirror. At all temperatures between 125 and 300 K, the responsivity at 150 mV bias exceeds 2.2 A/W and the EQE exceeds 61%. When the thermal background current for a realistic system scenario with f/4 optic that views a 300 K scene is derived from the observed EQE spectra, the resulting specific detectivity D* of 7.5 × 1012 cmHz½/W at 125 K operating temperature is 4.5 times higher than for a state-of-the-art broadband MWIR HgCdTe device. Simulations of the cavity performance indicate that EQE > 90% may be feasible following minimization of parasitic optical loss and maximization of the photocarrier collection efficiency. Potential applications include free space optical communication, chemical sensing, on-chip spectroscopy, and hyperspectral imaging.
Control of Tollmien–Schlichting waves using particle swarm optimization
Authors: Mohammadikalakoo B. , Kotsonis M. , Doan N. A. K.
Published: December 2024

The implementation of the Particle Swarm Optimization (PSO) algorithm is investigated to optimize the active attenuation of Tollmien–Schlichting (TS) waves developing in a two-dimensional zero pressure gradient boundary layer. This is done numerically, where the PSO algorithm optimizes the characteristics of harmonic suction and blowing jets, in a feedforward control framework. The PSO-based controller selects and modifies the phase and amplitude of the jets to minimize the pressure fluctuation amplitude downstream of the actuator. To allow for efficient simulation, the 2-dimensional incompressible Navier–Stokes equations are expanded in a harmonic perturbation form and solved in linear and nonlinear variants using harmonic balancing. This study explores the performance of control in both linear and nonlinear development regimes of TS waves through control of single and multi-frequency ensembles of instabilities. Respectively, linear and nonlinear controller design approaches are employed. The findings reveal that the integration of PSO into the control design produces an effective suppression of TS waves through opposition control. The linearly designed controller effectively attenuates single and multi-frequency disturbances. However, when applied in regions of strong nonlinear interactions among instability modes, performance degradation is observed. On the contrary, the nonlinearly designed controller proves effective in mitigating nonlinear multi-frequency instabilities dominating the later stages of growth. A near-complete elimination of TS waves is achieved by accounting for nonlinear interactions among harmonic modes detected by an input sensor. This highlights the benefit of integrating the PSO algorithm in control of TS waves, particularly in the nonlinear growth regime, where classical control methods are generally ineffective.
Waves and non-propagating mode in stratified and rotating magnetohydrodynamic turbulence
Authors: Mouhali W. , Salhi A. , Lehner T. , Cambon C.
Published: December 2024

In this study, we consider a freely decaying, stably stratified, and rotating homogeneous magneto-hydrodynamic (MHD) turbulent plasma with a vertical background magnetic field (B0=B0ẑ), aligned with the density gradient (with a constant Brunt–Váisálá frequency N) viewed in a frame rotating uniformly around the vertical axis (Ω0=Ω0ẑ). Quasi-linear theory is used to analyze the flow dynamics for an inviscid and non-diffusive Boussinesq fluid. We perform a normal mode decomposition emphasizing three types of motions: a non-propagating (NP) mode, which is no longer a vortex mode, and slow and fast magneto-inertia-gravity waves. The total energy as well as the L2 norm, say Γ, of the magnetic induction potential scalar (MIPS), which remains similar to the potential enstrophy for non-magnetized rotating and stratified flows, are inviscid invariants. In contrast with the potential vorticity for non-magnetized rotating and stratified flows, the MIPS is not affected by system rotation in the quasi-linear limit, and this is the effect of rotation which presumes an inverse cascade of energy in the equilibrium statistical mechanics. We characterized the system setting up our investigation from the point of view of equilibrium statistical mechanics in the limit of small Froude number and small Alfvén–Mach number. In this limit, the non-propagating quantity Γ can be approximated by its quadratic part that explicitly depends only on the vertical component of the fluctuating magnetic field and the density fluctuations. We demonstrate that the partition function restricted to the non-propagating manifold does not indicate an inverse cascade of energy.