bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ultrafast field-driven valley polarization of transition metal dichalcogenide quantum dots
Authors: Mitra Aranyo , Zafar Ahmal Jawad , Apalkov Vadym 
Published: February 2024

Abstract
We study theoretically the electron dynamics of transition metal dichalcogenide (TMDC) quantum dots (QDs) in the field of an ultrashort and ultrafast circularly polarized optical pulse. The QDs have the shape of a disk and their electron systems are described within an effective model with infinite mass boundary conditions. Similar to TMDC monolayers, a circularly polarized pulse generates ultrafast valley polarization of such QDs. The dependence of the valley polarization on the size of the dot is sensitive to the dot material and, for different materials, show both monotonic increase with the dot radius and nonmonotonic behavior with a local maximum at a finite dot radius.
Magnetic doping in transition metal dichalcogenides
Authors: Coelho Paula Mariel 
Published: February 2024

Abstract
Transition metal dichalcogenides (TMDCs) are materials with unique electronic properties due to their two-dimensional nature. Recently, there is a large and growing interest in synthesizing ferromagnetic TMDCs for applications in electronic devices and spintronics. Apart from intrinsically magnetic examples, modification via either intrinsic defects or external dopants may induce ferromagnetism in non-magnetic TMDCs and, hence expand the application of these materials. Here, we review recent experimental work on intrinsically non-magnetic TMDCs that present ferromagnetism as a consequence of either intrinsic defects or doping via self-flux approach, ion implantation or e-beam evaporation. The experimental work discussed here is organized by modification/doping mechanism. We also review current work on density functional theory calculations that predict ferromagnetism in doped systems, which also serve as preliminary data for the choice of new doped TMDCs to be explored experimentally. Implementing a controlled process to induce magnetism in two-dimensional materials is key for technological development and this topical review discusses the fundamental procedures while presenting promising materials to be investigated in order to achieve this goal.
Self-consistent quantum-kinetic theory for interacting drifting electrons and force-driven phonons in a 1D system
Authors: Lu Xuejun , Huang Danhong 
Published: February 2024

Abstract
A self-consistent quantum-kinetic model is developed for studying strong-field nonlinear electron transport interacting with force-driven phonons within a nanowire system. For this model, phonons can be dragged into motion through strong electron–phonon scattering by fast-moving electrons along the opposite direction of the DC electric field. Meanwhile, the DC-field induced charge current of electrons can be either enhanced or reduced by the same electron–phonon scattering, depending on the relative direction of a DC field with respect to that of an applied temperature gradient for driving phonons. By making use of this quantum-kinetic model beyond the relaxation-time approximation, neither electron nor phonon temperature is required for describing ultrafast electron–phonon scattering and their correlated transports in this 1D electronic-lattice system.
Liquid-filled pipeline leak detection and localization based on multi-scale residual networks
Authors: Zhao Si-Liang , Zhou Lin-Hui , Liu Shao-Gang , Dong Li-Qiang , Hong Zhou , Zhao Dan , Guo Chang 
Published: February 2024

Abstract
Effective ways to improve the accuracy of liquid-filled pipeline leak detection are one of the key issues that need to be addressed urgently in a conservation-oriented society. Recently, pipeline leak detection methods based on deep learning have developed rapidly. To improve the learning ability of convolutional neural network for pipeline leak signal features and leak detection accuracy, a multi-scale residual networks (MSRNs) model is proposed in this paper for liquid-filled pipeline leak detection and localization. The model uses convolutional kernels of different scales to extract multiscale features of pipeline leakage signals based on deep residual networks (DRNs) and uses fully connected layers to fuse the features, thus improving the accuracy of pipeline leakage detection and localization. Among them, the large convolution kernel can acquire the low-frequency information of the signal due to its sizable perceptual field, the medium convolution kernel can capture the local and global features of the signal, and the small convolution kernel is more sensitive to the high-frequency information of the signal. Meanwhile, a pipeline leakage test platform is built to evaluate the proposed model. The test results show that the accuracy of leak detection and localization of MSRN model is 98.3%, which is better than that of single-scale DRN model. In addition, the proposed MSRN model is verified to have good generalization and noise immunity through testing and analyzing the leakage signals under different pressures and background noises.
Semi-supervised low-dose SPECT restoration using sinogram inner-structure aware graph neural network
Authors: Li Si , Chen Keming , Ma Xiangyuan , Liang Zengguo 
Published: February 2024

Abstract

Objective. To mitigate the potential radiation risk, low-dose single photon emission computed tomography (SPECT) is of increasing interest. Numerous deep learning-based methods have been developed to perform low-dose imaging while maintaining image quality. However, most existing methods seldom explore the unique inner-structure inherent within sinograms. In addition, traditional supervised learning methods require large-scale labeled data, where the normal-dose data serves as annotation and is intractable to acquire in low-dose imaging. In this study, we aim to develop a novel sinogram inner-structure-aware semi-supervised framework for the task of low-dose SPECT sinogram restoration. Approach. The proposed framework retains the strengths of UNet, meanwhile introducing a sinogram-structure-based non-local neighbors graph neural network (SSN-GNN) module and a window-based K-nearest neighbors GNN (W-KNN-GNN) module to effectively exploit the inherent inner-structure within SPECT sinograms. Moreover, the proposed framework employs the mean teacher semi-supervised learning approach to leverage the information available in abundant unlabeled low-dose sinograms. Main results. The datasets exploited in this study were acquired from the (Extended Cardiac-Torso) XCAT anthropomorphic digital phantoms, which provide realistic images for imaging research of various modalities. Quantitative as well as qualitative results demonstrate that the proposed framework achieves superior performance compared to several state-of-the-art reconstruction methods. To further validate the effectiveness of the proposed framework, ablation and robustness experiments were also performed. The experimental results show that each component of the proposed framework effectively improves the model performance, and the framework exhibits superior robustness with respect to various noise levels. Besides, the proposed semi-supervised paradigm showcases the efficacy of incorporating supplementary unlabeled low-dose sinograms. Significance. The proposed framework improves the quality of low-dose SPECT reconstructed images by utilizing sinogram inner-structure and incorporating supplementary unlabeled data, which provides an important tool for dose reduction without sacrificing the image quality.
Impact of and interplay between proton arc therapy and range uncertainties in proton therapy for head-and-neck cancer
Authors: Tattenberg Sebastian , Liu Peilin , Mulhem Anthony , Cong Xiaoda , Thome Christopher , Ding Xuanfeng 
Published: February 2024

Abstract

Objective. Proton therapy reduces the integral dose to the patient compared to conventional photon treatments. However, in vivo proton range uncertainties remain a considerable hurdle. Range uncertainty reduction benefits depend on clinical practices. During intensity-modulated proton therapy (IMPT), the target is irradiated from only a few directions, but proton arc therapy (PAT), for which the target is irradiated from dozens of angles, may see clinical implementation by the time considerable range uncertainty reductions are achieved. It is therefore crucial to determine the impact of PAT on range uncertainty reduction benefits. Approach. For twenty head-and-neck cancer patients, four different treatment plans were created: an IMPT and a PAT treatment plan assuming current clinical range uncertainties of 3.5% (IMPT3.5% and PAT3.5%), and an IMPT and a PAT treatment plan assuming that range uncertainties can be reduced to 1% (IMPT1% and PAT1%). Plans were evaluated with respect to target coverage and organ-at-risk doses as well as normal tissue complication probabilities (NTCPs) for parotid glands (endpoint: parotid gland flow <25%) and larynx (endpoint: larynx edema). Main results. Implementation of PAT (IMPT3.5%−PAT3.5%) reduced mean NTCPs in the nominal and worst-case scenario by 3.2 percentage points (pp) and 4.2 pp, respectively. Reducing range uncertainties from 3.5% to 1% during use of IMPT (IMPT3.5%−IMPT1%) reduced evaluated NTCPs by 0.9 pp and 2.0 pp. Benefits of range uncertainty reductions subsequently to PAT implementation (PAT3.5%−PAT1%) were 0.2 pp and 1.0 pp, with considerably higher benefits in bilateral compared to unilateral cases. Significance. The mean clinical benefit of implementing PAT was more than twice as high as the benefit of a 3.5%–1% range uncertainty reduction. Range uncertainty reductions are expected to remain beneficial even after PAT implementation, especially in cases with target positions allowing for full leveraging of the higher number of gantry angles during PAT.
Effect of hyper-resistivity on ballooning modes with resonant magnetic perturbations
Authors: Chen S Y , Mou M L , Liu T Q , Zhang Y M , Dong L K , Fan H , Lu X , Tang C J 
Published: February 2024

Abstract
The impact of hyper-resistivity on non-ideal ballooning modes (BMs) is studied in the presence of resonant magnetic perturbation (RMP) through considering the hyper-resistivity, resistivity and diamagnetic effect in the BM model with an equilibrium distorted by RMP, which is stable for ideal BMs. Similar to the resistivity, the hyper-resistivity is also destabilizing for the BMs, but RMPs make the mode spectrum of the BMs destabilized by the hyper-resistivity move towards the low toroidal mode number side on the flux surface with a safety factor slightly larger than the RMP resonance safety factor, where the growth rates of the BMs destabilized by the resistivity decrease due to RMP. When both the hyper-resistivity and the resistivity are considered, there is a sort of competitive relationship between them in determining the properties of BMs. If either of the hyper-resistivity term and the resistivity term is much larger than the other one, the instability of BMs is mainly determined by the larger one, and the effect of the smaller one is masked. The destabilizing mechanisms of the hyper-resistivity and the resistivity on BMs are similar, namely, the diffusion and dissipation of current and magnetic field weaken the stabilizing effect of magnetic field line bending. The research results may be important for understanding the enhancement of plasma transport and the mechanism of small edge localized mode (ELM) during ELM control with RMP.
Absolute calibration of the ratio of Xe/O two-photon absorption cross-sections for O-TALIF applications
Authors: Shu Z , Popov N A , Starikovskaia S M 
Published: February 2024

Abstract
The paper presents a calibration of the ratio of two-photon absorption cross-sections,

σ

X
e

(
2
)

/

σ

O

(
2
)

, necessary for the absolute O-atom density measurements by two-photon absorption laser-induced fluorescence (TALIF) technique. To calibrate the ratio of the cross-sections, a special discharge with 100% dissociation of molecular oxygen, and so with a known ‘reference’ density of O-atom [O]

r
e
f

=
2
⋅

[O2] was suggested. This is a nanosecond capillary discharge in N2:O2 mixtures with a few percent of oxygen at a reduced electric field of a few hundred of Townsend and specific deposited energy of about 1 eV mol−1. Voltage at the electrodes, electrical current in the plasma, longitudinal electric field and energy delivered to the gas were measured with 0.2 ns synchronisation. Additionally, radial distribution of emission of excited nitrogen molecules and gas temperature in the discharge and afterglow were obtained experimentally. Detailed 1D kinetic modeling was suggested to confirm complete O2 dissociation and to analyse the main reactions. By comparing the data measured by TALIF technique with the ‘reference’ density of oxygen atoms [O]

r
e
f

, the ratio of the two-photon absorption cross-sections

σ

X
e

(
2
)

/

σ

O

(
2
)

was determined.
Polarization state conversion achieved by chiral mechanical metamaterial
Authors: Mangach Hicham , Achaoui Younes , Kadic Muamer , Bouzid Abdenbi , Guenneau Sébastien , Zeng Shuwen 
Published: February 2024

Abstract
Recently, metamaterials have driven advancements in wave propagation and polarization control. Chiral elastic metamaterials, in particular, have attracted considerable attention due to their distinctive properties, such as acoustical activity and auxeticity. Such characteristics arise from the additional degrees of freedom for tuning the embedded micro- and macro-rotations. In this study, we demonstrate an unusual energy exchange between longitudinal and in-plane shear waves in a 3D chiral mechanical metamaterial. The structural design is capable of inducing up to a 90∘ rotation in the plane of polarization. Additionally, this capacity for conversion is achieved by employing both an arrangement of chiral cells and a single meta-atom. This peculiar behavior enables a seamless switch between the three polarization states existing within a solid material, namely, the longitudinal state, the shear horizontal state, and the shear vertical state. Furthermore, a 2D discrete mono-atomic mass-spring model featuring inclined connectors is used to characterize the distinctive energy exchange between modes. This characterization is based on the retrieval of the pertinent elastic coefficients. The engineered chiral metamaterial polarization converter stands as a promising device for momentum conservation conversions and applications in elasto-dynamic polarimetry.
Novel hybrid-CMOS inverter utilizing phase transition material for enhancing digital logic performance at lower operating voltages
Authors: Sorot Ritika , Goel Anubha , Rewari Sonam 
Published: February 2024

Abstract
This research paper introduces a novel design for a hybrid-CMOS inverter using vanadium dioxide (VO2), a phase transition material. The proposed inverter exhibits a remarkably steep transition for falling logic at the output(1–0). By leveraging the insulating to metallic current density (IC-IMT) of VO2, the depth and gain of this transition can be finely tuned. Notably, a higher IC-IMT value yields a greater gain in the transition slope. In comparison to a traditional CMOS inverter, the designed inverter demonstrates several advantages. It achieves higher values of lower noise margin (NML) and significantly reduces static power dissipation by 97.7%. These promising outcomes present an exciting opportunity for designing inverters at lower drain voltages, especially in devices operating at lower technology nodes. Furthermore, the hybrid-CMOS inverter is designed to excel in the sub-threshold region of operation, resulting in elevated values of lower noise margin and reduced leakage current values.
Average trapping time on horizontally divided 3-dimensional 3-level Sierpinski gasket network
Authors: Sun Yu , Xiang Zuodong 
Published: February 2024

Abstract
An important characteristic of random wandering is the average trapping time, which is a hot issue in current research. The average trapping time is an important measure of the transmission efficiency of random wandering in a network. In this paper, we construct a 3-dimensional 3-level Sierpinski gasket network divided horizontally by the horizontal division plane P

s
, that is, the division coefficients s. We study the capture problem on the network and obtain an analytical expression for the average trapping time (ATT). Then, by adjusting the number of iterations and the values of the division coefficients, we obtained the relationship between ATT and them. As can be seen from our numerical simulation plots, ATT is affected by s. The larger s is, the more the self-similar structure of the three-dimensional residual network gradually transforms towards the structure of the two-dimensional complete Sierpinski gasket network. Meanwhile, the shorter ATT is, that is, the more efficient the transmission on the network.
Effect of transmutation rhenium on tensile properties of tungsten by molecular dynamics simulation
Authors: Wen Shulong , Pan Min 
Published: February 2024

Abstract
The tensile properties of W-Re alloys are studied using molecular dynamics method. Two forms of transmutation Re uniform distribution and cluster distribution in W-Re alloys are systematically explored, W-xRe alloys and W-nRe clusters, respectively. The effects of Re concentration, Re cluster number density, and temperature on the tensile properties are discussed. Findings suggest that Young’s modulus of W-xRe alloys decreases with increasing Re concentration, reaching only 323 GPa when the Re concentration is 50 at.%. The ultimate stress of W-xRe alloys is lower than that of pure tungsten, indicating that the presence of Re would accelerates the fracture of W-xRe alloys. Additionally, Re clusters of different sizes and number density are constructed in tungsten, forming the W-nRe cluster system. Interestingly Re clusters can reduce tensile strength, and the strain hardening modulus (E
sh) is independent of the single Re cluster size. With an increase in Re cluster number density, Young’s modulus, ultimate stress, and ultimate strain decrease gradually, leading to fracture in the Re cluster position. Non-coherent and semi-coherent interfaces between Re cluster (χ- and σ-phases) and W lattice cause Re cluster to undergo imbalance stress. For example, in W-12.5 at.% Re alloys, stress–strain curves are studied at different temperatures, revealing that Young’s modulus decreases with increasing temperature, reaching 292 GPa at 1300 K. A linear formula is obtained by fitting Young’s modulus-temperature curve. These results provide important theoretical references for the design of W-Re alloys as the PFMs in the ITER.
Effect of ingredients proportions on mechanical properties in laser-coated WC-blend welds
Authors: Wang ConRong , Zhong ZengQi , Jean Ming Der 
Published: February 2024

Abstract
In this study, we investigated ceramic-matrix composite coatings created by laser cladding on 45 steel using tungsten carbide (WC) powder with varying weight percentages of Co or Ni additives. Our analysis focused on the influence of Co additives in WC powders on the key properties of the coatings, including the microstructural evolution, hardness, wear, and residual stress behaviors. High residual stresses led to significant cracking in coatings comprising 100% WC. The addition of Co at a concentration of 20% to WC reduces the cracking activity. The microhardness of the coating exceeded that of the substrate by a factor of more than five. The microstructural evolution revealed a typical intergranular fracture in the molten zone, with cracks propagating through the interior of the unmelted WC at 100% WC. In addition, by adding Ni alloys, the composite coatings were extended to three mixtures: WC-Co, WC-Ni, and WC-Co-Ni. The relationship between the three-component mixtures and wear volume of the laser cladding was established, and the ratios of the three-component mixtures were optimized. A reduced quadratic model for three-component mixtures, which provided a better mixture ratio pattern, showed an excellent fit. Based on the experimental results, the developed three-component mixture with better mixture ratios can enhance anti-wear behavior. A satisfactory agreement was obtained between the predicted and experimental values of the wear volume of the laser-coated welds. Overall, our study accomplishes the optimization of the mixture ratio of the three components, which ensured a reduction in the wear of the welds, thereby improving the performance of laser-coated welds.
New evidence for CH4 enhancement in the upper troposphere associated with the Asian summer monsoon
Authors: Tao Mengchu , Cai Zhaonan , Zhu Sihong , Liu Yi , Feng Liang , Fang Shuangxi , Yi You , Bian Jianchun 
Published: February 2024

Abstract
The Asian summer monsoon (ASM) region is a key region transporting air to the upper troposphere (UT), significantly influencing the distribution and concentration of trace gases, including methane (CH4), an important greenhouse gas. We investigate the seasonal enhancement of CH4 in the UT over the ASM region, utilizing retrievals from the Atmospheric Infrared Sounder (AIRS), model simulations and in-situ measurements. Both the AIRS data and model simulation reveal a substantial enhancement in CH4 concentrations within the active monsoon region of up to 3%, referring to the zonal means, and of up to 6% relative to the pre-monsoon season. Notably, the spatial distribution of the CH4 plume demonstrates a southwestward shift in the AIRS retrievals, in contrast to the model simulations, which predict a broader enhancement, including a significant increase to the east. A cross-comparison with in-situ measurements, including AirCore measurements over the Tibetan Plateau and airline sampling across the ASM anticyclone (ASMA), favors the enhancement represented by model simulation. Remarkable CH4 enhancement over the west Pacific is also evidenced by in-situ data and simulation as a dynamical extension of the ASMA. Our findings underscore the necessity for cautious interpretation of satellite-derived CH4 distributions, and highlight the critical role of in-situ data in anchoring the assimilation of CH4.