bluuebunny/crossref_metadata_2025 huggingface dataset:
Accurate generation of stochastic dynamics based on multi-model generative adversarial networks
Authors: Lanzoni Daniele , Pierre-Louis Olivier , Montalenti Francesco
Published: October 2023

Generative Adversarial Networks (GANs) have shown immense potential in fields such as text and image generation. Only very recently attempts to exploit GANs to statistical-mechanics models have been reported. Here we quantitatively test this approach by applying it to a prototypical stochastic process on a lattice. By suitably adding noise to the original data we succeed in bringing both the Generator and the Discriminator loss functions close to their ideal value. Importantly, the discreteness of the model is retained despite the noise. As typical for adversarial approaches, oscillations around the convergence limit persist also at large epochs. This undermines model selection and the quality of the generated trajectories. We demonstrate that a simple multi-model procedure where stochastic trajectories are advanced at each step upon randomly selecting a Generator leads to a remarkable increase in accuracy. This is illustrated by quantitative analysis of both the predicted equilibrium probability distribution and of the escape-time distribution. Based on the reported findings, we believe that GANs are a promising tool to tackle complex statistical dynamics by machine learning techniques.
Predicting rate kernels via dynamic mode decomposition
Authors: Liu Wei , Chen Zi-Hao , Su Yu , Wang Yao , Dou Wenjie
Published: October 2023

Simulating dynamics of open quantum systems is sometimes a significant challenge, despite the availability of various exact or approximate methods. Particularly when dealing with complex systems, the huge computational cost will largely limit the applicability of these methods. In this work, we investigate the usage of dynamic mode decomposition (DMD) to evaluate the rate kernels in quantum rate processes. DMD is a data-driven model reduction technique that characterizes the rate kernels using snapshots collected from a small time window, allowing us to predict the long-term behaviors with only a limited number of samples. Our investigations show that whether the external field is involved or not, the DMD can give accurate prediction of the result compared with the traditional propagations, and simultaneously reduce the required computational cost.
Surface coverage dynamics for reversible dissociative adsorption on finite linear lattices
Authors: Mercado Enrique , Jung Hyun Tae , Kim Changho , Garcia Alejandro L. , Nonaka Andy J. , Bell John B.
Published: October 2023

Dissociative adsorption onto a surface introduces dynamic correlations between neighboring sites not found in non-dissociative absorption. We study surface coverage dynamics where reversible dissociative adsorption of dimers occurs on a finite linear lattice. We derive analytic expressions for the equilibrium surface coverage as a function of the number of reactive sites, N, and the ratio of the adsorption and desorption rates. Using these results, we characterize the finite size effect on the equilibrium surface coverage. For comparable N’s, the finite size effect is significantly larger when N is even than when N is odd. Moreover, as N increases, the size effect decays more slowly in the even case than in the odd case. The finite-size effect becomes significant when adsorption and desorption rates are considerably different. These finite-size effects are related to the number of accessible configurations in a finite system where the odd-even dependence arises from the limited number of accessible configurations in the even case. We confirm our analytical results with kinetic Monte Carlo simulations. We also analyze the surface-diffusion case where adsorbed atoms can hop into neighboring sites. As expected, the odd-even dependence disappears because more configurations are accessible in the even case due to surface diffusion.
Predissociation dynamics of the A2Σ+ state of SH radical: Fine-structure state distributions of the S(3PJ) products
Authors: Qin Yuan , Zheng Xianfeng , Song Yu , Sun Ge , Zhang Jingsong
Published: October 2023

Photo-predissociation of rovibrational levels of SH (A2Σ+, v′ = 0–6) is studied using the high-n Rydberg atom time-of-flight technique. Spin–orbit branching fractions of the S(3PJ=2,1,0) products are measured in the product translational energy distributions. The SH A2Σ+v′ = 0 state predissociates predominantly via coupling to the 4Σ− repulsive state. As the vibrational level v′ increases, predissociation dynamics change drastically, with all three repulsive states (4Σ−, 2Σ−, and 4Π) involved in the dissociation. Nonadiabatic interactions and quantum interferences among these dissociation pathways affect the fine-structure state distributions of the S(3PJ=2,1,0) products.
A nonequilibrium allosteric model for receptor-kinase complexes: The role of energy dissipation in chemotaxis signaling
Authors: Hathcock David , Yu Qiwei , Mello Bernardo A. , Amin Divya N. , Hazelbauer Gerald L. , Tu Yuhai
Published: October 2023

The
Escherichia coli
chemotaxis signaling pathway has served as a model system for the adaptive sensing of environmental signals by large protein complexes. The chemoreceptors control the kinase activity of CheA in response to the extracellular ligand concentration and adapt across a wide concentration range by undergoing methylation and demethylation. Methylation shifts the kinase response curve by orders of magnitude in ligand concentration while incurring a much smaller change in the ligand binding curve. Here, we show that the disproportionate shift in binding and kinase response is inconsistent with equilibrium allosteric models. To resolve this inconsistency, we present a nonequilibrium allosteric model that explicitly includes the dissipative reaction cycles driven by adenosine triphosphate (ATP) hydrolysis. The model successfully explains all existing joint measurements of ligand binding, receptor conformation, and kinase activity for both aspartate and serine receptors. Our results suggest that the receptor complex acts as an enzyme: Receptor methylation modulates the ON-state kinetics of the kinase (e.g., phosphorylation rate), while ligand binding controls the equilibrium balance between kinase ON/OFF states. Furthermore, sufficient energy dissipation is responsible for maintaining and enhancing the sensitivity range and amplitude of the kinase response. We demonstrate that the nonequilibrium allosteric model is broadly applicable to other sensor-kinase systems by successfully fitting previously unexplained data from the DosP bacterial oxygen-sensing system. Overall, this work provides a nonequilibrium physics perspective on cooperative sensing by large protein complexes and opens up research directions for understanding their microscopic mechanisms through simultaneous measurements and modeling of ligand binding and downstream responses.
Correlational analysis between salivary and blood glucose levels in individuals with and without diabetes mellitus: a cross-sectional study
Authors: Shettigar Laasya , Sivaraman Sanchita , Rao Rohini , Arun Sanjana Akhila , Chopra Aditi , Kamath Shobha U , Rana Raju
Published: October 2023

Objective: To estimate the association of patient-related demographic, socioeconomic status, physical activity, stress, and dietary factors influencing the relationship between salivary and blood glucose levels in individuals with and without diabetes mellitus (DM).
Method: This cross-sectional study was conducted on 166 participants with and without DM. Saliva and blood were collected to estimate the glucose levels. Age, gender, occupation, socioeconomic and education level, BMI, hip to waist circumference, stress, dietary pattern, lifestyle, physical activity, family history of diabetes, and type of diabetes were recorded. The association of saliva to predict blood glucose levels was analysed using Spearman Rank Correlation and how these patient-related factors influence the correlation was estimated for future machine learning models. The difference in medians for various groups was calculated using the Mann-Whitney U Test or Kruskal Wallis Test.
Results: Blood glucose level is not significantly correlated to salivary glucose level. However, a statistically significant difference in the median blood glucose levels for diabetic participants (median = 137) compared to healthy controls (p-value < .05) was noted. The correlation between blood and salivary glucose was more positive for higher levels of glucose (Spearman 0.4). Age, alcohol consumption, monthly wages, intake of vegetables, and socioeconomic status affect blood glucose levels.
Conclusion: A correlation between saliva and blood glucose levels in healthy individuals was weak. Saliva should only be used as a monitoring tool rather than a diagnostic tool and is more reliable for patients with poorly controlled diabetes mellitus.
3D-printed porous Al2O3 membrane coated with hydrophilic modified titanium dioxide particles for large-flux oil/water separation
Authors: Li Hao , Mei Hui , Jin Zhipeng , Pan Longkai , Cheng Laifei , Zhang Litong
Published: October 2023

A viable material to address oil pollution in water is the super wetting surface, which is accessible to realise the separation of oil and water. According to Young's equation, hydrophobic/oleophilic materials are theoretically simple to realise and have a wide range of applications. The hydrophobic/oleophilic membrane, however, has a poor separating effect on the mixture in which the oil has a lower density than water. Hence, to optimise the oil/water separation performance, hydrophilic modified titanium dioxide particles were introduced to a novel porous superhydrophilic/oleophobic substrate fabricated by 3D printing technology in this work. The contact angle of n-hexadecane on the membrane surface was about 130°, which was an oleophobic surface. The oil/water separation efficiency of the 0.7 mm thick oleophobic membrane was over 98% and the penetration flux was up to 11,191 L m−2 h−1, indicating that the membranes prepared in this work might be used in high-flux oil/water separation applications. This study provides an efficient, simple, and reliable method for preparing oil/water separation materials with 3D printing technology, and may have broader significance among the academic and industry communities.
pH gradients guide ADF/cofilin isoforms in pollen tubes
Authors: Dinet Céline , Michelot Alphée
Published: October 2023

In a recent study, Wang et al. (https://doi.org/10.1083/jcb.202206074) demonstrate that subtle differences between two ADF/cofilin isoforms allow fine spatial regulation of the actin cytoskeleton in pollen tubes. This article illustrates how two similar proteins have progressively evolved to adapt their localization and activity according to the cellular environment.
Evaluation of the contamination droplet model used for the assessment of skin dose during the manipulation of radiopharmaceuticals
Authors: Wicks Sarah , Heraghty Neil
Published: October 2023

The manipulation of radiopharmaceuticals in nuclear medicine can result in the droplet contamination of operators resulting in the accumulation of a significant skin dose. Current methods to estimate this skin dose often utilise a 50 μl cylindrical droplet model, which can lead to unrealistically high estimated skin doses for some radiopharmaceuticals. By conducting experiments to measure the volume of real droplets arising from simulating the manipulation of radiopharmaceuticals, this work found that 50 μl is an overestimation of a realistic contamination droplet. For almost all radiopharmaceuticals considered in this work, incorporating a smaller droplet volume into skin dose simulations resulted in higher estimates of skin dose rate per unit of activity, which, when combined with appropriate activity concentrations and droplet volumes, resulted in lower skin doses for contamination droplet incidents. The results presented in this work challenge the 50 μl contamination droplet volume and highlight the importance of having an accurate model when estimating the skin dose for contamination scenarios.
Micromagnetic and quantitative prediction of yield strength and tensile strength in DP590 steels based on ReliefF + Clustering feature selection method
Authors: Wang Xianxian , He Cunfu , Li Peng , Liu Xiucheng , Xing Zhixiang , Zhang Yangyang , Li Jinrun
Published: October 2023

The correlation between multiple patterns of micromagnetic signatures and the mechanical properties (yield strength (Rp) and tensile strength (Rm) of high-strength steel (referred to as DP590 steel in Chinese standards) was investigated in this study. Feedforward neural network (FF-NN) models with carefully selected magnetic features as input nodes were established for quantitative prediction of yield strength and tensile strength. The accuracy FF-NN models highly relied on the quality of calibration specimens and the way of selecting magnetic features. The variations of the measured target properties were used to evaluate the quality of the calibration specimens. The specimens with similar yield strength (or tensile strength) were merged to share the same target properties in the model training process. The results demonstrated that merging proper target properties (label) could improve the performance of the models in quantitative prediction of yield strength and tensile strength in DP590 steels. In addition, the performances of FF-NN models combined with the algorithms of ReliefF and ReliefF + clustering were evaluated. The comparison results proved that the FF-NN models employing input nodes selection strategy of ReliefF + clustering realized the advantages of smaller dimensions of input nodes, less training time consumption at the cost of slight accuracy reduction.
Online detection of analog signal anomaly based on the evaluation of local trends
Authors: Liu Yufang , Jiang Bin , Yi Hui
Published: October 2023

Online anomaly detection (AD) of analog signals plays an important role in equipment fault diagnosis and predictive maintenance. However, the signal often deviates slightly from those seen previously in the early stage of equipment failure, and the anomaly is invisible to the human eye. This kind of anomaly belongs to the typical contextual anomaly. Whether this anomaly can be effectively detected determines whether the failure of the equipment can be detected in the early stage, which is of great significance for safety in production. This study aimed to propose an online AD method for the analog signals of the quasi-sine waveform class. The sample similarity in the sliding window was evaluated using a sample trend rather than sample amplitude deviation to detect anomalies based on the principle that the trend of the quasi-sinusoid waveform signal in the adjacent space was similar. Compared with the traditional method, the proposed method was sensitive to contextual anomalies and did not need a complete sample data set for model training. The proposed method was finally validated by three data sets with good results.
Ag–N–C single atom catalyst with resistance for Ag loss in acetylene hydrochlorination
Authors: Liu Li , Lu Fangjie , Yin Xue , Yao Yuqi , Zhu Mingyuan , Dai Bin
Published: October 2023

Ag–N–C catalyst was synthesized by the calcination process with AgNO3 as precursors, active carbon as support, and melamine as an N source. Series of characterizations showed that Ag was transferred into AgCl during the active phase by HCl, and pyridinic structure in the support was bonded with Ag components. Then, Ag–N–C single atom catalyst (SAC) was obtained by washing Ag–N–C with acid, aberration-correction high-angle-annular-dark-field scanning transmission electron microscopy showed that Ag presented in single atoms form, and Ag coordinated with the nitrogen atom in the support. Ag loss rate for Ag–N–C SAC was only 0.09% after running 10 h in acetylene hydrochlorination process, which was much smaller than Ag–N–C (57%), indicating that the presence of the Ag–N bond could be inhibiting Ag species loss.
High-performance resistive random access memory using two-dimensional electron gas electrode and its switching mechanism analysis
Authors: Kim Jiho , Kwon Ohhyuk , Lee Kyumin , Han Geonhui , Hwang Hyunsang
Published: October 2023

In this study, a two-dimensional electron gas (2DEG), which is a conductive layer formed at the interface of Al2O3 and TiO2, was used as an electrode for resistive random access memory (RRAM) and implemented in a cell size down to 30 nm. For an RRAM device comprising W/2DEG/TiO2/W, we confirmed that the dominant switching mechanism changed from interfacial to filamentary as the cell size decreased from 500 nm to 30 nm. Through analyses of changes in forming characteristics and conduction mechanisms in the low resistive state depending on the cell size, it was identified that the 2DEG acted as an oxygen-scavenging layer of TiO2 during the resistive switching process. By comparing the switching characteristics of RRAM devices with and without 2DEG for a 30 nm cell size, we confirmed that a high-performance 2DEG RRAM was realized, with highly uniform current–voltage characteristics, a low operating voltage (∼1 V), and a high on/off ratio (>102). Finally, the applicability of the proposed device to a crossbar array was validated by evaluating 1S1R operation with an NbO2-based selector. Considering the improved switching uniformity, the 2DEG RRAM shows promise for high-density memory applications.
On variable viscosity and enhanced dissipation
Authors: Liao Xian , Zillinger Christian
Published: October 2023

In this article we consider the two-dimensional Navier–Stokes equations with variable viscosity depending on the vertical position. As our main result we establish linear enhanced dissipation near the non-affine stationary states replacing Couette flow. For instance, these shear flows may grow exponentially. Moreover it turns out that, in contrast to the constant viscosity case, decreasing viscosity leads to stronger enhanced dissipation and increasing viscosity leads to weaker dissipation.
Performance of LGAD strip detectors for particle counting of therapeutic proton beams
Authors: Monaco Vincenzo , Ali Omar Hammad , Bersani Davide , Abujami Mohammed , Boscardin Maurizio , Cartiglia Nicolò , Betta Gian Franco Dalla , Data Emanuele , Donetti Marco , Ferrero Marco , Ficorella Francesco , Giordanengo Simona , Villarreal Oscar Ariel Marti , Milian Felix Mas , Mohammadian-Behbahani Mohammad-Reza , Olivares Diango Montalvan , Pullia Marco , Tommasino Francesco , Verroi Enrico , Vignati Anna , Cirio Roberto , Sacchi Roberto
Published: October 2023

Objective. The performance of silicon detectors with moderate internal gain, named low-gain avalanche diodes (LGADs), was studied to investigate their capability to discriminate and count single beam particles at high fluxes, in view of future applications for beam characterization and on-line beam monitoring in proton therapy. Approach. Dedicated LGAD detectors with an active thickness of 55 μm and segmented in 2 mm2 strips were characterized at two Italian proton-therapy facilities, CNAO in Pavia and the Proton Therapy Center of Trento, with proton beams provided by a synchrotron and a cyclotron, respectively. Signals from single beam particles were discriminated against a threshold and counted. The number of proton pulses for fixed energies and different particle fluxes was compared with the charge collected by a compact ionization chamber, to infer the input particle rates. Main results. The counting inefficiency due to the overlap of nearby signals was less than 1% up to particle rates in one strip of 1 MHz, corresponding to a mean fluence rate on the strip of about 5 × 107 p/(cm2·s). Count-loss correction algorithms based on the logic combination of signals from two neighboring strips allow to extend the maximum counting rate by one order of magnitude. The same algorithms give additional information on the fine time structure of the beam. Significance. The direct counting of the number of beam protons with segmented silicon detectors allows to overcome some limitations of gas detectors typically employed for beam characterization and beam monitoring in particle therapy, providing faster response times, higher sensitivity, and independence of the counts from the particle energy.
A stochastic model of blood flow to calculate blood dose during radiotherapy
Authors: Beekman Chris , Withrow Julia D , Correa Alfonso Camilo M , Pathak Shreya P , Dawson Robert J , Carrasco-Rojas Natalia , Sforza Andrew R , Colon Carlos G , Bolch Wesley E , Grassberger Clemens , Paganetti Harald
Published: October 2023

Purpose. Lymphopenia is a common side effect in patients treated with radiotherapy, potentially caused by direct cell killing of circulating lymphocytes in the blood. To investigate this hypothesis, a method to assess dose to circulating lymphocytes is needed. Methods. A stochastic model to simulate systemic blood flow in the human body was developed based on a previously designed compartment model. Blood dose was obtained by superimposing the spatiotemporal distribution of blood particles with a time-varying dose rate field, and used as a surrogate for dose to circulating lymphocytes. We discuss relevant theory on compartmental modeling and how to combine it with models of explicit organ vasculature. Results. A general workflow was established which can be used for any anatomical site. Stochastic compartments can be replaced by explicit models of organ vasculatures for improved spatial resolution, and tumor compartments can be dynamically assigned. Generating a patient-specific blood flow distribution takes about one minute, fast enough to investigate the effect of varying treatment parameters such as the dose rate. Furthermore, the anatomical structures contributing most to the overall blood dose can be identified, which could potentially be used for lymphocyte-sparing treatment planning. Conclusion. The ability to report the blood dose distribution during radiotherapy is imperative to test and act upon the current paradigm that radiation-induced lymphopenia is caused by direct cell killing of lymphocytes in the blood. We have built a general model that can do so for various treatment sites. The presented framework is publicly available at http://github.com/mghro/hedos.
Multi-view fusion-based local-global dynamic pyramid convolutional cross-tansformer network for density classification in mammography
Authors: Zhong Yutong , Piao Yan , Zhang Guohui
Published: October 2023

Object. Breast density is an important indicator of breast cancer risk. However, existing methods for breast density classification do not fully utilise the multi-view information produced by mammography and thus have limited classification accuracy. Method. In this paper, we propose a multi-view fusion network, denoted local-global dynamic pyramidal-convolution transformer network (LG-DPTNet), for breast density classification in mammography. First, for single-view feature extraction, we develop a dynamic pyramid convolutional network to enable the network to adaptively learn global and local features. Second, we address the problem exhibited by traditional multi-view fusion methods, this is based on a cross-transformer that integrates fine-grained information and global contextual information from different views and thereby provides accurate predictions for the network. Finally, we use an asymmetric focal loss function instead of traditional cross-entropy loss during network training to solve the problem of class imbalance in public datasets, thereby further improving the performance of the model. Results. We evaluated the effectiveness of our method on two publicly available mammography datasets, CBIS-DDSM and INbreast, and achieved areas under the curve (AUC) of 96.73% and 91.12%, respectively. Conclusion. Our experiments demonstrated that the devised fusion model can more effectively utilise the information contained in multiple views than existing models and exhibits classification performance that is superior to that of baseline and state-of-the-art methods.
Generalisation of radiotherapy dose calculation for Monte Carlo algorithm combined with 3D Swin-Unet: a multi-institutional IMRT evaluation
Authors: Zhang Bailin , Zhuang Yongdong , Li Yinghui , Chen Lixin , Liu Xiaowei , Liu Zhibin , Wang Xuetao , Zhu Jinhan
Published: October 2023

Objective. Accurate dose calculations are essential prerequisites for precise radiotherapy. The integration of deep learning into dosimetry could consider computational accuracy and efficiency and has potential applicability to clinical dose calculation. The generalisation of a deep learning dose calculation method (hereinafter referred to as TERMA-Monte Carlo network, T-MC net) was evaluated in clinical practice using intensity-modulated radiotherapy (IMRT) plans for various human body regions and multiple institutions, with the Monte Carlo (MC) algorithm serving as a benchmark. Approach. Sixty IMRT plans were selected from four institutions for testing the head and neck, chest and abdomen, and pelvis regions. Using the MC results as the benchmark, the T-MC net calculation results were used to perform three-dimensional dose distribution and dose-volume histogram (DVH) comparisons of the entire body, planning target volume (PTV) and organs at risk (OARs), respectively, and calculate the mean ±95% confidence interval of gamma pass rate (GPR), percentage of agreement (PA) and dose difference ratio (DDR) of dose indices D95, D50, and D5. Main results. For the entire body, the GPRs of 3%/3 mm, 2%/2 mm, 2%/1 mm, and the PA were 99.62 ± 0.32%, 98.50 ± 1.09%, 95.60 ± 2.90% and 97.80 ± 1.12%, respectively. For the PTV, the GPRs of 3%/3 mm, 2%/2 mm, 2%/1 mm and the PA were 98.90 ± 1.00%, 95.78 ± 2.83%, 92.23 ± 4.74% and 98.93 ± 0.62%, respectively. The absolute value of average DDR was less than 1.4%. Significance. We proposed a general dose calculation framework based on deep learning, using the MC algorithm as a benchmark, performing a generalisation test for IMRT treatment plans across multiple institutions. The framework provides high computational speed while maintaining the accuracy of MC and may become an effective dose algorithm engine in treatment planning, adaptive radiotherapy, and dose verification.
Specular highlight removal for endoscopic images using partial attention network
Authors: Zhang Chong , Liu Yueliang , Wang Kun , Tian Jie
Published: October 2023

Objective. Endoscopic imaging is a visualization method widely used in minimally invasive surgery. However, owing to the strong reflection of the mucus layer on the organs, specular highlights often appear to degrade the imaging performance. Thus, it is necessary to develop an effective highlight removal method for endoscopic imaging. Approach. A specular highlight removal method using a partial attention network (PatNet) for endoscopic imaging is proposed to reduce the interference of bright light in endoscopic surgery. The method is designed as two procedures: highlight segmentation and endoscopic image inpainting. Image segmentation uses brightness threshold based on illumination compensation to divide the endoscopic image into the highlighted mask and the non-highlighted area. The image inpainting algorithm uses a partial convolution network that integrates an attention mechanism. A mask dataset with random hopping points is designed to simulate specular highlight in endoscopic imaging for network training. Through the filtering of masks, the method can focus on recovering defective pixels and preserving valid pixels as much as possible. Main results. The PatNet is compared with 3 highlight segmentation methods, 3 imaging inpainting methods and 5 highlight removal methods for effective analysis. Experimental results show that the proposed method provides better performance in terms of both perception and quantification. In addition, surgeons are invited to score the processing results for different highlight removal methods under realistic reflection conditions. The PatNet received the highest score of 4.18. Correspondingly, the kendall’s W is 0.757 and the asymptotic significance p = 0.000 < 0.01, revealing that the subjective scores have good consistency and confidence. Significance. Generally, the method can realize irregular shape highlight reflection removal and image restoration close to the ground truth of endoscopic images. This method can improve the quality of endoscopic imaging for accurate image analysis.
A flexible magnetic detector based on transferred ferroelectric/ferromagnetic thin film heterostructure
Authors: Liang Kun , Chen Zhiqiang , Yao Shuai , Tan Haibin , Zhou Peng , Ma Zhijun , Qi Yajun , Zhang Tianjin
Published: October 2023

A flexible magnetic detector based on ferroelectric/ferromagnetic (PZT/Metglas) thin film heterostructure is developed by using etching and transferring technique. The transferred PZT film still exhibits (001)-oriented or very highly textured structure with good ferroelectricity (P
r = 50 μC cm−2 and E
c = 150 kV cm−1). Magnetoelectric (ME) voltage coefficient of the PZT/Metglas film heterostructure approaches 5.1 V cm−1 Oe at resonance frequency (57.5 kHz). The flexible detector has a sensitivity of AC 0.3 nT and DC 1 Oe with high stability for magnetic field detection. Our demonstration provides a viable approach for realizing ME thin film transfer technology, which is of great significance for future applications on flexible magnetic detectors.
Superconducting joints of reacted monofilament MgB2 wires sintered by hot uniaxial pressing system
Authors: Liang Hao , Morawski Andrzej , Patel Dipak , Cetner Tomasz , Billah Md Motasim , Rindfleisch Matt , Taylor Richard , Yamauchi Yusuke , Hossain Md Shahriar A
Published: October 2023

Successful superconducting joints of reacted magnesium diboride (MgB2) monofilament wires are reported in this paper. The absence of a reliable method to develop superconducting joints between reacted MgB2 wires presents a major obstacle to the wider adoption of MgB2 as a material for magnet winding. A hot uniaxial pressing (HUP) system was exploited for sintering purposes since it can facilitate the formation of condensed in situ bulk on the wire filament. The wires were manufactured with an extra thick barrier material to protect the filament from damage during HUP sintering. The sintering temperature and pressure of the HUP system were varied to comprehend the best-performing joint. The performance of joints could be improved by depreciating the pores within the intermediate bulk of the joint. To prove this point, joints were cut to study their morphology. However, due to sintering in pressurised conditions, the reaction of the in situ intermediate bulk was not completed. The x-ray diffraction result detected a significant unreacted magnesium phase in the intermediate bulk. This work obtained joints of reacted MgB2 wires which can be considered for industrial MgB2 magnetic resonance imaging magnets fabrication.
XUV fluorescence as a probe of laser-induced helium nanoplasma dynamics
Authors: Sumfleth Malte , Przystawik Andreas , Namboodiri Mahesh , Laarmann Tim
Published: October 2023

XUV fluorescence spectroscopy provides information on energy absorption and dissipation processes taking place in the interaction of helium clusters with intense femtosecond laser pulses. The present experimental results complement the physical picture derived from previous electron and ion spectroscopic studies of the generated helium nanoplasma. Here, the broadband XUV fluorescence emission from high-lying Rydberg states that covers the spectral region from

6
p
→
1
s

at 53.0 eV all the way to photon energies corresponding to the ionization potential of He+ ions at 54.4 eV is observed directly. The cluster size-dependent population of these states in the expanding nanoplasma follows the well-known bottleneck model. The results support previous findings and highlight the important role of Rydberg states in the energetics and dynamics of laser-generated nanoplasma.
Broadband achromatic metalens design based on predictive neural network and particle swarm optimization-genetic algorithm
Authors: Zhang Cheng , Chen Mingsheng , Zhang Liru , Zhang Ru , Cheng Hong , Shen Chuan , Wei Sui
Published: October 2023

The main challenge in designing broadband achromatic metalenses is to achieve the desired phase distribution at different wavelengths and positions. Finding the exact relationship between phase modulation and the size or shape of individual nanopillars is a critical but time-consuming step. This paper presents a novel joint design framework predictive neural networks and particle swarm optimization-genetic algorithms, which combines predictive neural network (PNN) and particle swarm optimization-genetic algorithm (PSO-GA). The proposed framework aims to accurately predict the phase response of nanopillars using PNN, increase the number of phase data points to establish a one-to-one correspondence between the phase and nanopillar parameters in the design of broadband achromatic metalenses, and optimize the parameters of an individual nanostructure of the metalens using PSO-GA. To validate the efficacy of the proposed method, a broadband achromatic metalens for line polarization light in the range of 260–350 nm is designed. Numerical simulations demonstrate that the designed metalens exhibits achromatic focusing. The method proposed in this paper may find wider application in the design of more complex metasurface devices.
Constraints on extended Jordan-Brans-Dicke gravity
Authors: Kaneta Kunio , Oda Kin-ya , Yoshimura Motohiko
Published: October 2023

Cosmological analysis of
extended Jordan-Brans-Dicke (eJBD) gravity is presented
in the Einstein metric frame in which gravitational interaction is readily understandable.
Our formulation is the first systematic investigation of how to
introduce lagrangian of standard particle physics
in eJBD framework consistently with the general principle of spontaneously broken
gauge symmetry, which makes it possible to
confront eJBD-based cosmology
with observational and laboratory bounds on time variation
of parameters, masses, and coupling constants,
caused by time evolution of eJBD fields.
Decomposition of standard particle physics lagrangian into
independent gauge invariant pieces is
proposed to avoid serious conflict that may arise from standard
lagrangian transformed from the Jordan frame.
Independent conformal factors are assigned to each of
five gauge invariant pieces.
The formulation is most unambiguously made possible by
defining fields having canonical kinetic terms
that allow us to use the canonical quantization rule of field theory.
This construction gives as one of its consequences
the canonical eJBD field χ that couples to
the universal fermion current, a linear combination of
baryon and lepton number currents,
 ∂μχ
(3 jμ
B
+ jμ
L
),
in addition to the conventional trace of the energy-momentum tensor.
Field equation of eJBD field along with gravitational equation is analyzed by using a simplified
polynomial class of potential and conformal functions,
giving time evolution of radiation, matter and dark energy densities
consistent with observations when an appropriate set of model parameters
are used.
Finite temperature corrections are further calculated to give
temperature dependent terms in eJBD field potential.
Bianchi type cosmological models in f(T) tele-parallel gravity
Authors: van den Hoogen R.J. , Coley A.A. , McNutt D.D.
Published: October 2023

Symmetry assumptions on the geometrical framework have provided successful mechanisms to develop physically meaningful solutions to many problems. In tele-parallel gravity, invariance of the frame and spin-connection under a group of motions defines an affine symmetry group. Here, we assume there exists a three-dimensional group of affine symmetries acting simply transitively on a spatial hypersurface and that this group of symmetry actions defines our affine frame symmetry group. We determine the general form of the co-frame and spin connection for each spatially homogeneous Bianchi type. We then construct the corresponding field equations forf(T) tele-parallel gravity. We show that if the symmetry group is of Bianchi type A (I,II,VI0,VII0,VIIIorIX) then there exists a co-frame/spin connection pair that is consistent with the antisymmetric part of the field equations off(T) tele-parallel gravity. For those geometries having a Bianchi type B symmetry group (IV,V,VIh,VIIh), we find that in general these geometries are inconsistent with the antisymmetric part of thef(T) tele-parallel gravity field equations unless the theory reduces to an analog of General Relativity with a cosmological constant.
Effect of sample temperature on femtosecond laser ablation of copper
Authors: Dang 党 Wei-Jie 伟杰 , Chen 陈 Yu-Tong 雨桐 , Chen 陈 An-Min 安民 , Jin 金 Ming-Xing 明星
Published: October 2023

We conduct an experimental study supported by theoretical analysis of single laser ablating copper to investigate the interactions between laser and material at different sample temperatures, and predict the changes of ablation morphology and lattice temperature. For investigating the effect of sample temperature on femtosecond laser processing, we conduct experiments on and simulate the thermal behavior of femtosecond laser irradiating copper by using a two-temperature model. The simulation results show that both electron peak temperature and the relaxation time needed to reach equilibrium increase as initial sample temperature rises. When the sample temperature rises from 300 K to 600 K, the maximum lattice temperature of the copper surface increases by about 6500 K under femtosecond laser irradiation, and the ablation depth increases by 20%. The simulated ablation depths follow the same general trend as the experimental values. This work provides some theoretical basis and technical support for developing femtosecond laser processing in the field of metal materials.
Divertor power load investigations with deuterium and tritium in type-I ELMy H-mode plasmas in JET with the ITER-like wall
Authors: Faitsch M. , Balboa I. , Lomas P. , Silburn S.A. , Tookey A. , Kos D. , Huber A. , de la Luna E. , Keeling D. , Kappatou A. ,   JET Contributors
Published: October 2023

Divertor power load is a major challenge towards a burning plasma in a next-step tokamak. Here, the first results of a divertor power load characterisation in tritium plasmas in type-I ELMy H-mode, obtained in the JET deuterium-tritium campaign (DTE2) performed in 2021, are presented. It is demonstrated that both, transient loads due to type-I ELMs as well as the power fall-off length, do not exhibit an explicit ion mass dependence, with remarkably similar values in the tritium plasmas and in the deuterium references. This gives an improved credence to published scaling law predictions, solely based on deuterium plasma experiments. Moreover, the type-I ELM impact on the inner divertor target is studied in deuterium discharges. A slightly increased parallel energy fluence on the inner target with a factor of 1.08 compared to the outer target is observed. This is explained by the smaller major radius of the inner target.
Isotope mass scaling and transport comparison between JET Deuterium and Tritium L-mode plasmas
Authors: Tala T. , Järvinen A.E. , Maggi C.F. , Mantica P. , Mariani A. , Salmi A. , Carvalho I.S. , Chomiczewska A. , Delabie E. , Devasagayam F. , Ferreira J. , Gromelski W. , Hawkes N. , Horvath L. , Karhunen J. , King D. , Kirjasuo A. , Kowalska-Strzeciwilk E. , Leerink S. , Lennholm M. , Lomanowski B. , Maslov M. , Menmuir S. , Morales R.B. , Sharma R. , Sun H. , Tanaka K. ,   JET Contributors
Published: October 2023

The dimensionless isotope mass scaling experiment between pure Deuterium and pure Tritium plasmas with matched

ρ
∗

,

ν
∗

, β

n
, q and

T
e

/

T
i

has been achieved in JET L-mode with dominant electron heating (NBI+ohmic) conditions. 28% higher scaled energy confinement time

B
t

τ

E
,

t
h

/

A

is found in favour of the Tritium plasma. This can be cast in the form of the dimensionless energy confinement scaling law as

Ω
i

τ

E
,

t
h

∼

A

0.48
±
0.16

. This significant isotope mass scaling is consequently seen in the scaled one-fluid heat diffusion coefficient

A

χ

e
f
f

/

B
t

which is around 50% lower in the Tritium plasma throughout the whole plasma radius. The isotope mass dependence in the particle transport channel is negligible, supported also by the perturbative particle transport analysis with gas puff modulation. The comparison of the edge particle fuelling or ionisation profiles from the EDGE2D-EIRENE simulations show that the absolute density differences that are necessary for the dimensionless match in the confined plasma dominate over any isotope mass dependencies of particle fuelling and ionization profiles at the plasma edge. Local GENE simulation results indicate a mild anti-gyroBohm effect at

ρ

t
o
r

= 0.6 and thereby a small isotope mass dependence in favour of Tritium on heat transport and a negligible effect on particle transport. A significant fraction of the isotope scaling and reduced heat transport observed in the Tritium plasma is not captured in the GENE and ASTRA-TGLF-SAT2 simulations by simply changing the isotope mass for the same input profiles.
Modelling performed for predictions of fusion power in JET DTE2: overview and lessons learnt
Authors: Garcia J. , Casson F.J. , Frassinetti L. , Gallart D. , Garzotti L. , Kim H.-T. , Nocente M. , Saarelma S. , Auriemma F. , Ferreira J. , Gabriellini S. , Ho A. , Huynh P. , Kirov K.K. , Lerche E. , Mantsinen M.J. , Zotta V.K. , Stancar Z. , Taylor D.M.A. , Van Eester D. , Challis C.D. ,   JET Contributors
Published: October 2023

For more than a decade, an unprecedented predict-first activity has been carried in order to predict the fusion power and provide guidance to the second Deuterium–Tritium (D–T) campaign performed at JET in 2021 (DTE2). Such an activity has provided a framework for a broad model validation and development towards the D–T operation. It is shown that it is necessary to go beyond projections using scaling laws in order to obtain detailed physics based predictions. Furthermore, mixing different modelling complexity and promoting an extended interplay between modelling and experiment are essential towards reliable predictions of D–T plasmas. The fusion power obtained in this predict-first activity is in broad agreement with the one finally measured in DTE2. Implications for the prediction of fusion power in future devices, such as ITER, are discussed.
L-H transition studies in tritium and deuterium–tritium campaigns at JET with Be wall and W divertor
Authors: Solano E.R. , Birkenmeier G. , Silva C. , Delabie E. , Hillesheim J.C. , Baciero A. , Balboa I. , Baruzzo M. , Boboc A. , Brix M. , Bernardo J. , Bourdelle C. , Carvalho I.S. , Carvalho P. , Challis C.D. , Chernyshova M. , Chomiczewska A. , Coelho R. , Coffey I. , Craciunescu T. , de la Cal E. , de la Luna E. , Dumont R. , Dumortier P. , Fontana M. , Fontdecaba J.M. , Frassinetti L. , Gallart D. , Garcia J. , Giroud C. , Gromelski W. , Henriques R.B. , Hall J. , Ho A. , Horton L.D. , Horvath L. , Jacquet P. , Jepu I. , Joffrin E. , Kappatou A. , Keeling D.L. , King D.B. , Kiptily V.G. , Kirov K.K. , Kos D. , Kowalska-Strzęciwilk E. , Lennholm M. , Lerche E. , Litherland-Smith E. , Loarte A. , Lomanowski B. , Lomas P.J. , Maggi C.F. , Mailloux J. , Mantsinen M.J. , Maslov M. , Meigs A.G. , Monakhov I. , Morales R.B. , Nielsen A.H. , Nina D. , Noble C. , Pawelec E. , Poradzinski M. , Pucella G. , Puglia P. , Réfy D. , Rasmussen J. Juul , Righi E. , Rimini F.G. , Robinson T. , Sertoli M. , Silburn S.A. , Sips G. , Sirén P. , Štancar Ž. , Sun H.J. , Szepesi G. , Taylor D. , Tholerus E. , Thomas B. , Verdoolaege G. , Vincenzi P. , Viola B. , Vianello N. , Wilson T. ,   JET Contributors
Published: October 2023

The recent deuterium–tritium campaign in JET-ILW (DTE2) has provided a unique opportunity to study the isotope dependence of the L-H power threshold in an ITER-like wall environment (Be wall and W divertor). Here we present results from dedicated L-H transition experiments at JET-ILW, documenting the power threshold in tritium and deuterium–tritium plasmas, comparing them with the matching deuterium and hydrogen datasets. From earlier experiments in JET-ILW it is known that as plasma isotopic composition changes from deuterium, through varying deuterium/hydrogen concentrations, to pure hydrogen, the value of the line averaged density at which the threshold is minimum,nˉe,min, increases, leading us to expect thatnˉe,min(T) <nˉe,min(DT) <nˉe,min(D) <nˉe,min(H). The new power threshold data confirms these expectations in most cases, with the corresponding ordering of the minimum power thresholds. We present a comparison of this data to power threshold scalings, used for extrapolation to future devices such as ITER and DEMO.
Stability analysis of alpha driven toroidal Alfvén eigenmodes observed in JET deuterium-tritium internal transport barrier plasmas
Authors: Fitzgerald M. , Dumont R. , Keeling D. , Mailloux J. , Sharapov S. , Dreval M. , Figueiredo A. , Coelho R. , Ferreira J. , Rodrigues P. , Nabais F. , Borba D. , Štancar Ž. , Szepesi G. , Tinguely R.A. , Puglia P.G. , Oliver H.J.C. , Kiptily V. , Baruzzo M. , Lennholm M. , Siren P. , Garcia J. , Maggi C.F. ,   JET Contributors
Published: October 2023

A toroidal Alfvén eigenmode (TAE) has been observed to be driven by alpha particles in a JET deuterium-tritium internal transport barrier plasma. The observation occurred 50 ms after the removal of neutral beam heating (NBI). The mode is observed on magnetics, soft-xray, interferometry and reflectometry measurements. We present detailed stability calculations using a similar tool set validated during deuterium only discharges. These calculations strongly support the conclusion that the observed mode is a TAE, and that this mode was destabilized by alpha particles. Non-ideal effects from the bulk plasma are interpreted as responsible for suppressing the majority of TAEs which were also driven by alpha particles, but the modes that match the observations are predicted to be particularly weak for these non-ideal effects. This mode located far from the core on the outboard midplane is found to be driven by both trapped and passing particles despite alpha particles originating in the core.