bluuebunny/crossref_metadata_2025_split huggingface dataset:
High-temperature ultraviolet photodetector and amplifying integrated circuits based on AlGaN/GaN heterostructure
Authors: Tang Xi , Liu Xiaoyu , Zhao Chunyu , Niu Kui , Li Ziyun , Li Hui , Li Baikui , Wang Jiannong 
Published: December 2024

Abstract
In this work, an ultraviolet (UV) photodetection and amplifying integrated circuit (IC) based on an AlGaN/gallium nitride (GaN) heterostructure is demonstrated. The IC consists of a metal-heterostructure-metal photodetector (MHM-PD) and a high-electron-mobility transistor (HEMT)-based amplifier. The photoresponse of the MHM-PD increases at elevated temperatures due to the spatial separation of the photocarriers under the polarization electric field at the AlGaN/GaN heterointerface, as well as the photo-enhanced leakage current through the metal-heterostructure junction. At 250 °C, MHM-PD achieves a peak photoresponsivity of 14.5 A W−1 and a UV-to-visible rejection ratio of 104. As the thermal chuck temperature increases from 25 °C to 250 °C, the performance of the HEMT-based amplifier shows good thermal stability. Finally, the IC achieves a photoresponse of over 106 V W−1 and a switching frequency of 50 kHz at 250 °C with rise and decay time constants of 3.95 μs and 2.8 μs, respectively. These results show that the IC has a high-sensitivity and high-speed UV detection capability.
Influence of band occupation on electron-phonon coupling in gold
Authors: Held Tobias , Weber Sebastian T , Rethfeld Baerbel 
Published: December 2024

Abstract
Electron-phonon coupling is a fundamental process that governs the energy relaxation dynamics of solids excited by ultrafast laser pulses. It has been found to strongly depend on the electron temperature as well as on nonequilibrium effects. Recently, the effect of occupational nonequilibrium in noble metals, which outlasts the fully kinetic stage, has come into increased focus. In this study, we investigate the influence of nonequilibrium density distributions in gold on the electron-phonon coupling. We find a large effect on the coupling parameter which describes the energy exchange between electrons and phonons. Our results challenge the conventional view that electron temperature alone is a sufficient predictor of electron-phonon coupling.
Design, construction and validation of a magnetic particle imaging (MPI) system for human brain imaging
Authors: Mattingly Eli , Śliwiak Monika , Mason Erica , Chacon-Caldera Jorge , Barksdale Alex , Niebel Frauke H , Herb Konstantin , Graeser Matthias , Wald Lawrence L 
Published: December 2024

Abstract

Objective. Magnetic particle imaging (MPI) was introduced in 2005 as a promising, tracer-based medical imaging modality with the potential for high sensitivity and spatial resolution. Since then, numerous preclinical devices have been built but only a few human-scale devices, none of which targeted functional neuroimaging. In this work, we probe the challenges of scaling the technology to meet the needs of human functional neuroimaging with sufficient sensitivity for detecting the hemodynamic changes following brain activation with a spatio-temporal resolution comparable to current functional magnetic resonance imaging approaches. Approach. We built a human brain-scale MPI system using a mechanically-rotated, permanent-magnet-based field-free line (FFL) (

1.1

Tm

−
1

) with a water-cooled, 26 kHz drive coil producing a field of up to 7 mT

peak

, and receive coil that can fit over a human head. Images are acquired continuously at a temporal resolution of 5 s/image, controlled by in-house LabView-based acquisition software with online reconstruction. We used a dilution series to quantify the detection limit, a series of parallel-line phantoms to assess the spatial resolution, and a large ‘G’ shaped phantom to demonstrate the human-scale field of view (FOV). Main results. The imager has a sensitivity of about 1 µg

Fe

over a 2D imaging FOV of 181 mm diameter(132 pixels) in a 5 s image. Depending on the image reconstruction used, the spatial resolution defined by 50% contrast between adjacent lines was 5–7 mm. Significance. This proof-of-concept system demonstrates a pathway for human MPI functional neuroimaging with the potential for an order of magnitude increase of sensitivity compared to the other human hemodynamic imaging methods. It demonstrates the successful transition of the FFL based MPI architecture from the rodent to human scale and identifies areas which could benefit from further work.
Thin film photo(electro)catalysts for the generation of energetic vectors: success cases and challenges, a brief review
Authors: Alfaro Cruz M R , Luévano-Hipólito E , Garay-Rodríguez L F , Torres-Martínez Leticia M 
Published: December 2024

Abstract
Thin-film semiconductors are excellent candidates for converting solar energy into chemical energy via water splitting because of their outstanding physical and chemical properties. This review aims to provide the most recent findings on the production of energetic vectors from photo-(electro-)catalytic water splitting using thin-film semiconductors as catalysts. Recent successful cases are discussed to provide the scientific community with a guide for the design of new and advanced thin-film semiconductors with maximum efficiency for scaling the process. In addition, the use of coatings to provide a higher amount of catalyst for photo(electro)catalytic H2 production is discussed. Some of the most critical challenges in this reaction, such as charge recombination, light absorption, catalyst recovery, and stability, have been effectively addressed by applying thin films. In addition, the design of adequate thin-film photo(electro)chemical reactors is a critical step in improving efficiency and avoiding mass transfer limit steps. However, further research is required to provide continuous and low-cost manufacturing deposition techniques that favor optimal conditions to produce clean and renewable H2.
Ontology for smart 4D printed material systems and structures synergically applied with generative artificial intelligence for creativity promotion
Authors: Solórzano-Requejo William , Vega Carlos Aguilar , Martínez Rodrigo Zapata , Bodaghi Mahdi , Lantada Andrés Díaz 
Published: December 2024

Abstract
This study presents a versatile ontology for describing all kinds of smart or stimuli-responsive 4D printed material systems and structures. The different components of the ontology, namely: initial geometry and shape, shape-morphing principle(s), triggering stimuli, intermediate/final geometry and shape, 4D material and printing or additive manufacturing technology, are enumerated and classified. Accordingly, a codification system for schematically illustrating the actuation cycle of 4D printed material systems and structures, and shape-morphing devices in general, is proposed. The systematic application of the ontology to a relevant set of examples helps to demonstrate its utility and adaptability to many different types of 4D printed objects. It demonstrates that the ontology and codification schemes developed in this research can serve a comprehensive classification tool for the emergent field of 4D printing. It is the first ontology capable of representing the multiple actuation steps of complex 4D printed devices and actuators, in which several metamorphoses may be achievable, due to combinations of different shape-morphing principles and triggering stimuli. To this end, a single line of code is required. A glossary is provided to support its implementation and application. Besides, the usability of the ontology and related codification by a generative artificial intelligence (AI) for supporting engineering design tasks is explored and validated through a set of examples and an industrial use case. This work is expected to provide a universal language to facilitate the communication in the 4D materials and printing field, as well as a synergic generative AI-based methodology for creativity promotion linked to innovative smart 4D printed material systems and structures.
On the magnetic layer behind a shock wave
Authors: Núñez Manuel 
Published: December 2024

Abstract
The growth in temperature behind a shock wave generates a sharp increase in the fluid conductivity. In the presence of a possible background magnetic field originating in the obstacle forming the bow shock, this creates a Lorentz force which acts upon the flow. Since this enhanced conductivity in hypersonic flows is limited to a narrow layer behind the shock, where also the density increases markedly, one is able to use some reasonable approximations to analyze the magnetohydrodynamic equations associated to the flow. This is performed in the plane and axisymmetric cases, with eminently intuitive results: the transverse component of the magnetic field acts as a brake, while the longitudinal component presses the streamlines against the body or separates them from it. Details for poloidal and toroidal fields are quite different.
Variational principles of physics and the infinite Ramsey theory
Authors: Bormashenko Edward 
Published: December 2024

Abstract
Application of the Ramsey Infinite Theorem to the fundamental variational principles of physics is addressed. The Hamilton Least Action Principle states that, for a true/actual trajectory of a system, Hamilton’s Action is stationary for the paths, which evolve from the preset initial space-time point to the preset final space-time point. The Hamilton Principle distinguishes between the actual and trial/test trajectories of the system in the configurational space. This enables the transformation of the infinite set of points of the configurational space (available for the system) into the bi-colored, infinite, complete, graph, when the points of the configurational space are seen as the vertices, actual paths connecting the vertices/ points of the configurational space are colored with red; whereas, the trial links/paths are colored with green. Following the Ramsey Infinite Theorem, there exists the infinite, monochromatic sequence of the pathways/clique, which is completely made up of actual or virtual paths, linking the interim states of the system. The same procedure is applicable to the Maupertuis’s principle (classical and quantum), Hilbert-Einstein relativistic variational principle and reciprocal variational principles. Exemplifications of the Infinite Ramsey Theorem are addressed.
Fundamental vector soliton dynamics governed by Kerr and Raman nonlinearities in optical fiber
Authors: Ibarra-Villalon H E , Pottiez O , Gómez-Vieyra A , Lauterio-Cruz J P 
Published: December 2024

Abstract
This work analyzes numerically the propagation of a fundamental vector soliton in presence of a Raman soliton self-polarization shift (RSSPS) effect driven by the self- and cross-frequency shift that are induced by the stimulated Raman scattering (SRS), which is modeled by two coupled nonlinear Schrödinger equations in a circular polarization basis. Particularly, the propagation of the fundamental vector soliton, as a sech-squared temporal pulse profile, is also governed by a compensation balance between dispersion and Kerr effect. In this analysis, the numerical approach for solving the propagation problem is studied in detail. Additionally, for a better understanding of the vector soliton dynamics, the pulse propagation governed by linear and nonlinear effects, considering their individual contributions as well as their simultaneous interplay, are studied by spectrograms, which represent the temporal-spectral distribution of the pulse profile. As a result, the fundamental vector soliton, which maintains its temporal envelope over propagation, validates a temporal walk-off along propagation that is consistent with a redshifted spectral evolution; at the same time, the polarization evolution is correlated with this pulse dynamics.
Preparation and characterization of CuInSe2 (CIS) thin films by one-step electrodeposition: corrosion analysis
Authors: Akgüney Ali Can , Akdağ Adem , Demir Kübra Çınar 
Published: December 2024

Abstract
In this study, it was focused on the structural and morphological and the corrosion properties of CIS NTFs electrodeposited on ITO substrates before and after annealing. After deposition, the CIS NTFs were annealed for 30 min. at 400 °C in a nitrogen (N2) atmosphere. X-ray diffraction (XRD) analysis indicated that CIS NTFs crystallize in a tetragonal structure typical of the chalcopyrite phase, exhibiting a preferential orientation along the (112) plane and the CIS NTFs exhibited an increase in grain size after annealing. Raman analysis showed that the wavenumbers at 210 cm−1 and 288 cm−1 reveal the characteristic modes of the chalcopyrite phase of CIS after the annealing. The roughness of the CIS NTFs was measured at 108 nm before annealing, and this value increased after the annealing. The corrosion rate of the CIS NTFs was recorded at 6.04 × 10−4 mm y−1 before annealing and this value decreased after annealing. The findings indicate that the increase in grain size subsequently was attributed to improved corrosion resistance after annealing and the increase of the corrosion resistance performed the more protective layer in CIS NTFs after annealing.
A comparative hybrid-DFT study of energy-efficient halide perovskite under hydrostatic pressure
Authors: Shoaib Hassan Syed , Gillani S S A 
Published: December 2024

Abstract
To achieve the main goal of this research, follow these steps to perform a detailed computational analysis using the Heyd–Scuseria–Ernzerhof (HSE-03) hybrid functional. This analysis will cover the structural, electrical, elastic, mechanical, anisotropic, and optical properties of halide perovskite materials CsPbX3 (X = Cl, Br, and I) by applying pressure from 0 to 25 GPa. Under stress, all materials exhibit a consistent decrease in lattice parameters and a decrease in band gap up to 25 GPa. To explore the electronic band structure (BS), we have estimated the TDOS (Total Density of States) and EPDOS (Elemental Partial Density of States). To further assess the material's relevance, we calculated several optical properties including absorption I (ω), extinction coefficient k (ω), refractive index n (ω), loss function L (ω), reflectivity R (ω), the real part of the dielectric function

ε

1

(
ω
)

and the imaginary part

ε

2

(
ω
)

. The static values of reflectivity R (ω), the real part of the dielectric function

ε

1

(
ω
)

increase by applying pressure on all materials. With the pressure application, the peak of absorption peak under study perovskites shifts markedly towards higher photon energies. Moreover, its high refractive index, reflectivity, and absorption make it an important element for optoelectronic devices. The structure retains its cubic form and there is no change in phase in all three materials. The materials are stiff, unyielding, and mechanically stable demonstrating elevated resistance to shear stress based on different mechanical and elastic parameters, including Young’s modulus, bulk modulus, and shear modulus. The Pugh/Frantsevich ratios, Kleinman’s parameter, Cauchy pressure, and Poisson’s ratio, indicate the ductility of materials, metallic bonding characteristics, and resilience under high pressure. Additionally, distinctive anisotropy factors are used to confirm the material's anisotropic properties.
Simulation of Li-pellet triggered ELMs in EAST with an impurity model implemented under BOUT++ framework
Authors: Li Mao , Sun Zhen , Sun Jizhong , Chang Huayi , Xia Tianyang 
Published: December 2024

Abstract
A simple impurity model has been developed under the BOUT++ framework to investigate the Li-pellet triggered edge localized mode (ELM) in EAST configuration. The present impurity model decouples the ion pressure enhancement effect (IPEE) (which affects radial E

×

B flow shear and gyro-viscosity of deuterium ions and is implicitly included in our previous work) to make the simulation of Li pellet injection more physically reasonable. In addition, the present impurity model also includes the impurity equilibrium effect (IEE) (which induces modifications on vorticity and gyro-viscosity). The simulation results show that without IPEE a turbulent ELM induced by Li pellet is triggered by multiple peeling-ballooning modes (PBMs) rather than by a single dominant mode, and the simultaneous growth of multiple modes is conducive to reducing the time for pedestal entering the energy loss state. When a turbulent ELM occurs, the nonlinearly dominant modes undergo a secondary fast growth during fast crash phase. The finding explains the secondary increase of

D
α

emission observed in the DIII-D Li injection experiments. During the evolution of a turbulent ELM, the continuous pedestal collapse dominates the pedestal energy loss in turbulent transport phase; however, in saturation phase, the stabilizing effects on PBMs (n

≠

0) by n = 0 mode and radial E

×

B flow shear within the steepest gradient region are more prominent. It is also found that with IEE and without IPEE, the size threshold of ELM triggering and the magnitude of ELM sizes both show a good agreement with EAST and DIII-D experimental observations.
A HVSR inversion method based on the multi-modal forest optimization algorithm
Authors: Chen Xuanning , Han Fuxing , Gao Zhenghui , Sun Zhangqing , Han Jiangtao , Chen Changle , Zhou Yanwei , Li Gang 
Published: December 2024

Abstract
The exploration of urban underground spaces is of great significance to urban planning, geological disaster prevention, resource exploration, and environmental monitoring. However, due to severe interferences, conventional seismic methods cannot adapt to the complex urban environment well. Since adopting the single-node data acquisition method and taking the seismic ambient noise as the signal, the microtremor horizontal to vertical spectral ratio (HVSR) method can effectively avoid the strong interference problems caused by the complex urban environment, which could obtain information such as S-wave velocity and thickness of underground formations by fitting the microtremor HVSR curve. Nevertheless, HVSR curve inversion is a multi-parameter curve fitting process. Conventional inversion methods can easily converge to the local minimum, directly affecting the inversion results’ reliability. Thus, we propose a HVSR inversion method based on the multimodal forest optimization algorithm, which uses the efficient clustering technique and can locate the global optimum quickly. Tests on synthetic data show that the inversion results of the proposed method are consistent with the forward model. Both the adaption and stability to the abnormal layer velocity model are also demonstrated. The results of the real field data are also verified by the drilling information.
Research on improving power system stability with AC excitation VSPSH based on BPA
Authors: Wang Yingwei , Chen Lei , Yue Mingyi , Zhang Shunren , Zhang Guangqing , Gong Wenjun 
Published: December 2024

Abstract
In the process of achieving the “Dual Carbon” goals, there is an increasing integration of new energy sources into China’s power system, particularly the large-scale connection of wind power, which poses new challenges to the safe and stable operation of the grid. Compared to constant-speed pumped-storage hydropower units (CSPSH), variable-speed pumped-storage hydropower units (VSPSH) with adjustable speed characteristics demonstrate significant potential in the construction of a modernized power system. This paper constructs a three-machine-nine-node system model of a 300MW VSPSH with extensive wind power integration under the BPA environment. Through power disturbances and fault settings, the paper observes the enhancement of system stability after the integration of the VSPSH and evaluates the regulation effectiveness of the VSPSH.
A framework for demand response load forecasting based on federated learning
Authors: Zhang Pan , Chen Gang , Sun Lu , Wang Shujie 
Published: December 2024

Abstract
Addressing the scenario where distribution network operators predict load curves based on user data to participate in demand response, and to cope with issues such as user data privacy protection and the operators’ lack of permission to access metering data, this paper proposes a framework and method for demand response load forecasting based on federated learning. Focusing on features including weather, time, and users’ participation status in demand response, this approach utilizes horizontal federated learning technology to integrate data from various sources while safeguarding user data privacy. Furthermore, a balanced scheduling scheme for participating users and samples, along with data preprocessing, is integrated to enable effective discrimination of load curves. Case study analysis demonstrates that the proposed load forecasting method can maintain superior prediction performance while ensuring the privacy of user data.
Electromagnetic scattering characterization of a layered rough soil ground
Authors: Zhang Jiangong , Yu Pengcheng , Gan Zheyuan , Chen Yajie , Cao Xiaoyu , Zhao Zhibin , Jiao Chaoqun 
Published: December 2024

Abstract
As the density of additional ultra-high voltage alternating current and direct current transmission lines in China increases, so does the passive interference from transmission lines to various types of equipment. At present, the objective of previous studies is to examine the impact of passive interference on the performance of transmission lines, ignoring the impact of rough soil ground on the passive interference of transmission line. Put it another way, the earth as a pure conductor processing, the use of this simplified processing method of the results obtained from the measured value is often a large deviation. For this reason, this paper considers the added transmission line erected in the rough soil ground environment. A more realistic passive interference model for ultra-high voltage transmission lines developed. We are looking at how electromagnetic waves behave when they are transmitted through different types of rough soil. To do this, we have created a model of layered rough soil using the Monte Carlo method. Then, the scattering coefficients of layered rough soil ground at two stations are calculated by going to use the method of moments. In the end, the effects of roughness change and distance change of layered rough soil ground on the scattering coefficients are investigated, and a model of layered rough soil ground is established on the basis of single-layered rough ground to take a look at how electromagnetic waves behave when they hit layered, uneven soil.
Analysis of the influence of power supply on control and protection device for voltage source converter-based high voltage direct current
Authors: Huang Xionghui , Ren Chenglin , Cai Yongliang , Peng Maolan , Liu Tao , Xiao Hongyou 
Published: December 2024

Abstract
The high-frequency DC switching power supply is a core module in control and protection devices for voltage source converter-based high voltage direct current (VSC-HVDC) systems. In practice, this type of power supply is often prone to failure. This paper investigates the working circuit of the switching power supply and examines various quality issues with power supply components. It focuses on aluminum electrolytic capacitors and key circuit DC/DC converters, which are particularly failure-prone. The study establishes a model for these components and analyzes the effects of capacitance reduction and increased equivalent series resistance, which result from capacitor failures. Through simulation experiments, the research explores the impact of these quality issues on DC/DC circuits. This work lays the foundation for understanding how the power module affects the VSC-HVDC protection device.