bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dynamic evolution of metal nanoclusters revealed by in-situ electron microscopy
Authors: Zhang Luyao , Zhang Lei , Yu Boyuan , Wang Rongming , Yang Feng 
Published: July 2023

Abstract
Nanoclusters involve finite metal atoms are of great importance in chemical synthesis and catalysis due to their unique structure-dependent properties. Knowing how nanoclusters work in reaction conditions is no doubt one of the most important challenges, which requires deep insight into atomic-scale dynamics during the process. State-of-the-art in-situ transmission electron microscope (TEM) can realize the real-time study, which is expected to reveal insights into the underlying mechanisms of catalysis and design efficient catalysts. In this minireview, we aim to give a critical review and recent progress on nanocluster dynamics unveiled by in-situ and environmental TEM from two aspects: evolutions of metal single atoms and nanoclusters in high-temperature reaction conditions and the well-defined molecular clusters in confined space. We emphasize the cluster-environment interaction and the cluster structure–property relationships. In the end, we also summarize the present achievements and propose future challenges. We expect this review will fuel the excitement and stimulate research in the fields of cluster and catalysis.
Glass fiber network reinforced polyethylene terephthalate composites for support insulators
Authors: Liang Zuodong , Zhuang Weijian , Lin Chuanjie , Liang Fangwei , Fan Xianhao , Zhu Yujie , Li Qi , Li Chuanyang , He Jinliang 
Published: July 2023

Abstract
Epoxy resin has long been used as an insulating material in high-voltage apparatus, although its poor recyclability greatly limits its future application. Fiber network reinforced polyethylene terephthalate (PET), as a low-cost and recyclable material, has great potential to substitute epoxy resin as a high-voltage insulation material. The enhanced fiber network combined with the PET matrix form a semi-‘steel-reinforced concrete’ structure, and can collaboratively improve the tensile strength by more than 50% and the dielectric strength by 25.4%. Furthermore, the breakdown path as well as the fiber distribution are clearly rebuilt in 3D coordinates based on a 3D x-ray microscope for the first time. Experimental and computational evidence show that the fiber network lengthens the breakdown path and improves the dielectric strength. This work provides new perspectives for subsequent research on the electrical properties of bone-enhanced dielectric polymer composite.
A new numerical approach for efficient modeling of positive corona discharge and its associated electric wind
Authors: Yanallah K , Chelih A , Bouazza M R , Pontiga F , Bouadi M , Vázquez P A , Bendaoudi Z 
Published: July 2023

Abstract
Research on corona wind generation has been increasing in recent years because of its potential technological applications, particularly those related to improving heat transfer in small-scale devices. Since numerical simulations play a key role in the design of these applications, computationally efficient modeling of corona discharge is imperative. This work presents a new approach that allows rapid computation of the electrohydrodynamic (EHD) force density responsible for the generation of electric wind. Arbitrary electrode configurations can easily be dealt with in the model, since only the Laplacian electric field lines have to be determined numerically. Then, using approximated analytical approximations of the electric field intensity along the field lines, the spatial distribution of the current density and the space charge density can be easily determined. The model has been satisfactorily tested against experimental measurements of the current–voltage characteristic and the current density distribution on the cathode. Furthermore, the electric wind computed from the EHD force agrees quite satisfactorily with measurements carried out in different electrode configurations. Finally, the model has been applied to a new electrode configuration that has greater potential for heat transfer applications.
Multifunctional metamaterial for realizing absorption and polarization conversion on the basis of vanadium dioxide
Authors: Qiu Yu , Yan Dexian , Feng Qinyin , Li Xiangjun , Zhang Le , Li Jining 
Published: July 2023

Abstract
In this paper, the phase change material vanadium dioxide (VO2) is introduced to propose a tunable multifunctional metamaterial device, which treats the phase change property of VO2 to realize the switching of absorption, linear to linear (LTL) polarization conversion, and linear to circular (LTC) polarization conversion functions. When VO2 is in metal state, the structure can be applied as an absorber to achieve the wide-band and narrow-band absorption. In the broad frequency area of 2.007–2.803 THz, the absorption is above 90%. And the narrow-band absorption near the center frequency 1.0126 THz reaches 95.04%. When VO2 is in the insulator state, the studied device can be treated as a polarization conversion device to achieve LTL and LTC polarization conversion. In the low frequency range, the device achieves LTL with polarization conversion efficiency (PCR) above 90% when the frequency is between 0.439 and 0.907 THz. In the high frequency range, the structure can be treated as the LTC polarization converter to achieve right-hand circular polarization, left-hand circular polarization (LHCP), and LHCP in the ranges of 2.317–2.329 THz, 2.356–2.531 THz and 2.582–2.633 THz, respectively. In addition, the ellipticity is above 0.9. Finally, the effects of geometric parameters, angle of incidence and polarization angle on the absorption and PCR are also discussed. The proposed structure has great potential for advanced technologies such as imaging, sensing, communication, and stealth.
Low-frequency electrical response related to oxygen vacancies in Al3+ substituted M-type hexaferrite
Authors: Singh Hodam Karnajit , Mohapatra Prajna P , Dobbidi Pamu , Chittari Bheema Lingam 
Published: July 2023

Abstract
The presence of oxygen vacancies is unavoidable in many complex metal oxide materials such as hexaferrites. This article investigates the role of crystal defects, such as oxygen vacancies, and different oxidation states of Fe ions, on the electrical conduction behaviors of Al3+ substituted Ba0.4La0.1Sr0.5Al
x
Fe12−x
O19 hexaferrites by analyzing the temperature dependent AC impedance and AC conductivity. The optimal substitution of La3+ ions and high-temperature sintering is responsible for forming oxygen vacancies while reducing Fe from Fe3+ to Fe2+ cations, as observed in structural and XPS analysis, which affects electrical conduction behaviors. The departure from ideal Debye-type relaxation behavior is also one of the effects of crystal defects. Temperature variation of relaxation time shows a sharp change at around 403 K. This may be due to different electrical entities influencing the mode of electron hopping with temperature. The activation energy calculated from the temperature dependent relaxation time confirmed the presence of electron hopping through the bridging effects of the first ionization of oxygen vacancies Fe2+–

V

o

⋅

–Fe3+ below a temperature of 403 K. Above 403 K, electron hopping through different oxidation states of Fe3+ + e− → Fe2+ and migration of oxygen vacancies toward the bulk surface are responsible for the conduction mechanism. The DC resistivity and AC conductivity show that the bridging effects of oxygen defects can also induce Coulomb interaction between the defect sites resulting in Efros–Shklovskii variable range hopping and correlation barrier hopping below 403 K. Above 403 K, polaron-assisted electron hopping is more desirable, as confirmed by the non-overlapping small polaron tunneling model.
Active topological defect absorption by a curvature singularity
Authors: Vafa Farzan , Nelson David R , Doostmohammadi Amin 
Published: July 2023

AbstractWe leverage the Born–Oppenheimer approximation to present a general description of topological defects dynamics inp-atic materials on curved surfaces. Focusing on the case of an active nematic, we find that activity induces a geometric contribution to the motility of the+1/2defect. Moreover, in the case of a cone, the simplest example of a geometry with curvature singularity, we find that the motility depends on the deficit angle of the cone and changes sign when the deficit angle is greater thanπ, leading to the change in active behavior from contractile (extensile) to extensile (contractile) behavior. Using our analytical framework, we then identify for positively charged defects the basin of attraction to the cone apex and present closed-form predictions for defect trajectories near the apex. The analytical results are quantitatively corroborated against full numerical simulations, with excellent agreement when the capture radius is small compared to the cone size.
Field-free spin-orbit torque switching in interlayer exchange coupled Co/Ta/CoTb
Authors: Wu Chuangwen , Zhou Xiangqing , Zeng Guang , Sun Chen , Li Peizhi , Li Jiaxu , Chen Shiwei , Yang Guang , Liang Shiheng 
Published: July 2023

Abstract
This study investigates a T-type field-free spin-orbit torque device with an in-plane magnetic layer coupled to a perpendicular magnetic layer via a non-magnetic spacer. The device utilizes a Co/Ta/CoTb structure, in which the in-plane Co layer and the perpendicular CoTb layer are ferromagnetically (FM) coupled through the Ta spacer. ‘T-type’ refers to the magnetization arrangement in the FM/spacer/FIM structure, where the magnetization in FM is in-plane, while in FIM, it is out-of-plane. This configuration forms a T-shaped arrangement for the magnetization of the two magnetic layers. Additionally, ‘interlayer exchange coupling (IEC)’ denotes the interaction between the two magnetic layers, which is achieved by adjusting the material and thickness of the spacer. Our results show that an in-plane effective field from the IEC enables deterministic current-induced magnetization switching of the CoTb layer. The field-driven and the current-driven asymmetric domain wall motion are observed and characterized by magneto-optic Kerr effect measurements. The functionality of multistate synaptic plasticity is demonstrated by understanding the relationship between the anomalous Hall resistance and the applied current pulses, indicating the potential for the device in spintronic memory and neuromorphic computing.
GEMIMEG-II — How metrology can go digital
...
Authors: Engel Thomas 
Published: July 2023

Abstract
The GEMIMEG-II project is intended to pave the way for digitalization in metrology. The central element of this digitalization initiative is the digital calibration certificate (DCC). It contains all calibration information in full digital form. This means, that it is machine readable and machine understandable without human interaction. This enables its utilization by being securely machine interpretable and machine actionable in the entire chain of truly digital workflows and information technology (IT) environments in Industry 4.0. Therefore, the DCC is created automatically in the calibration process in a standardized form based on a digital document schema. This systematic schema enables to safely transfer, process, and interpret all data in the DCC automatically in all subsequent IT based processes. This paper reflects the project status of GEMIMEG-II in its final phase and shares some insights on the concepts developed and solutions implemented as the results will be demonstrated in five Realbeds. Furthermore, the concept of quality of sensing and quality of data will be introduced as it is implemented in the GEMIMEG-II project to convey supplementary information on the measurement, environmental and/or surrounding modalities, and data quality. Finally, a brief outlook will be given on next steps and actions planned in the project related to other digitalization initiatives for the fab of the future.
In situ fabrication of Cu–Mn–O nanostructure catalysts on Ti mesh and their catalytic property optimization for low-temperature and stable CO oxidation
Authors: Zhang Ruishi , Zhou Yang , Li Yunheng , Li Jing , Tang Xinyue , Liu Baodan 
Published: July 2023

Abstract
A series of interlaced ‘tripe-shaped’ nanoflake catalysts made of CuMn2O4 were in situ prepared on Ti mesh substrate through the associated methods of plasma electrolyte oxidation and hydrothermal technique. The surface morphology, elemental distribution and chemical state, phase composition and microstructure of CuMn2O4 nanostructures prepared under different conditions were systemically investigated. To evaluate the catalytic activity, the CO oxidation as a probe reaction was used, and the results showed that 12h-Cu1Mn2-300 (hydrothermal reaction at 150 °C for 12 h, Cu/Mn = 1/2 in initial precursor, heat treatment temperature at 300 °C) exhibited the best CO oxidation capability with T
100 = 150 °C owe to the formation of uniform CuMn2O4 nanosheet layers in situ grown on flexible Ti mesh and the synergistic effect of Cu and Mn species in spinel CuMn2O4, which makes it more active towards CO oxidation than pure copper/manganese oxides.
Colourful phase change material-incorporated flexible film for efficient passive radiative cooling
Authors: Zhang Yuruo , Liu Xianghui , Li Zhenyang , Xie Wei , Lou Xing , Fan Yile , Cao Kangli , Liu Gang , Kondo Hiroki , Zhou Han 
Published: July 2023

Abstract
Passive radiative cooling involves the emission of thermal radiation into cold space and the reflection of solar radiation, which aims to cool and lower the temperature of objects. However, currently most radiative coolers have a white appearance which restricts their potential applications. We develop a coloured bilayer radiative cooling membrane using polyvinylidene fluoride/tetraethoxysilane (PVDF/TEOS) fibres, with incorporation of phase change materials (PCMs) and active dyes through a simple and large-area electrospinning process. In comparison to traditional emitters, PCM-incorporated colourful coolers provide energy storage capacity and colourful appearances. Our phase-transition-based colourful flexible film (PCFF) achieves a total solar reflectance of 0.81 and a mid-infrared (8–13 μm) emissivity of 0.85 with superior mechanical strength and good hydrophobicity. We experimentally demonstrate that our PCFF can significantly reduce the temperature of objects exposed to direct sunlight, with a cooling effect of up to 9 °C compared to commercial fabrics of similar materials and colours. Our work provides a promising starting point for the design and manufacture of colourful and flexible thermal control films.
Pulmonary nodules segmentation based on domain adaptation
Authors: Sui Guozheng , Zhang Zaixian , Liu Shunli , Chen Shuang , Liu Xuefeng 
Published: July 2023

AbstractWith the development of deep learning, the methods based on transfer learning have promoted the progress of medical image segmentation. However, the domain shift and complex background information of medical images limit the further improvement of the segmentation accuracy. Domain adaptation can compensate for the sample shortage by learning important information from a similar source dataset. Therefore, a segmentation method based on adversarial domain adaptation with background mask (ADAB) is proposed in this paper. Firstly, two ADAB networks are built for the source and target data segmentation, respectively. Next, to extract the foreground features that are the input of the discriminators, the background masks are generated according to the region growth algorithm. Then, to update the parameters in the target network without being affected by the conflict between the distinguishing differences of the discriminator and the domain shift reduction of the adversarial domain adaptation, a gradient reversal layer propagation is embedded in the ADAB model for the target data. Finally, an enhanced boundaries loss is deduced to make the target network sensitive to the edge of the area to be segmented. The performance of the proposed method is evaluated in the segmentation of pulmonary nodules in computed tomography images. Experimental results show that the proposed approach has a potential prospect in medical image processing.
VAEs with structured image covariance applied to compressed sensing MRI
Authors: Duff M A G , Simpson I J A , Ehrhardt M J , Campbell N D F 
Published: July 2023

Abstract

Objective.This paper investigates how generative models, trained on ground-truth images, can be used as priors for inverse problems, penalizing reconstructions far from images the generator can produce. The aim is that learned regularization will provide complex data-driven priors to inverse problems while still retaining the control and insight of a variational regularization method. Moreover, unsupervised learning, without paired training data, allows the learned regularizer to remain flexible to changes in the forward problem such as noise level, sampling pattern or coil sensitivities in MRI. Approach. We utilize variational autoencoders that generate not only an image but also a covariance uncertainty matrix for each image. The covariance can model changing uncertainty dependencies caused by structure in the image, such as edges or objects, and provides a new distance metric from the manifold of learned images. Main results. We evaluate these novel generative regularizers on retrospectively sub-sampled real-valued MRI measurements from the fastMRI dataset. We compare our proposed learned regularization against other unlearned regularization approaches and unsupervised and supervised deep learning methods. Significance. Our results show that the proposed method is competitive with other state-of-the-art methods and behaves consistently with changing sampling patterns and noise levels.
The truth Hertz—synchronization of electroencephalogram signals with physiological waveforms recorded in an intensive care unit
Authors: Goodwin Andrew J , Dixon William , Mazwi Mjaye , Hahn Cecil D , Meir Tomer , Goodfellow Sebastian D , Kazazian Vanna , Greer Robert W , McEwan Alistair , Laussen Peter C , Eytan Danny 
Published: July 2023

Abstract

Objective. The ability to synchronize continuous electroencephalogram (cEEG) signals with physiological waveforms such as electrocardiogram (ECG), invasive pressures, photoplethysmography and other signals can provide meaningful insights regarding coupling between brain activity and other physiological subsystems. Aligning these datasets is a particularly challenging problem because device clocks handle time differently and synchronization protocols may be undocumented or proprietary. Approach. We used an ensemble-based model to detect the timestamps of heartbeat artefacts from ECG waveforms recorded from inpatient bedside monitors and from cEEG signals acquired using a different device. Vectors of inter-beat intervals were matched between both datasets and robust linear regression was applied to measure the relative time offset between the two datasets as a function of time. Main Results. The timing error between the two unsynchronized datasets ranged between −84 s and +33 s (mean 0.77 s, median 4.31 s, IQR25-4.79 s, IQR75 11.38s). Application of our method improved the relative alignment to within ± 5ms for more than 61% of the dataset. The mean clock drift between the two datasets was 418.3 parts per million (ppm) (median 414.6 ppm, IQR25 411.0 ppm, IQR75 425.6 ppm). A signal quality index was generated that described the quality of alignment for each cEEG study as a function of time. Significance. We developed and tested a method to retrospectively time-align two clinical waveform datasets acquired from different devices using a common signal. The method was applied to 33,911h of signals collected in a paediatric critical care unit over six years, demonstrating that the method can be applied to long-term recordings collected under clinical conditions. The method can account for unknown clock drift rates and the presence of discontinuities caused by clock resynchronization events.
Density limits as disruption forecasters for spherical tokamaks
Authors: Berkery J W , Sabbagh S A , Ham C J , Zamkovska V , Butt J , Riquezes J , Tobin M , Henderson S , Kogan L , Patel B S , Scannell R , Trier E , LeBlanc B 
Published: July 2023

Abstract
Fusion power output from spherical tokamaks would benefit from increased confined plasma density, but there exists a limit on the density before confinement is lost and the plasma current is disrupted. This density limit has long been characterized by a simple, global Greenwald limit proportional to the plasma current and inversely proportional to the cross sectional area of the plasma. It is shown that in the database of discharges from the National Spherical Tokamak Experiment (NSTX) and Mega Ampere Spherical Tokamak (MAST) spherical tokamaks, the likelihood of disruption does increase above the Greenwald limit, and especially in the plasma current rampdown phase. The physics of the density limit has been recently theoretically explored through local criteria. Several of these are tested using the disruption event characterization and forecasting (DECAFTM) code for their potential effectiveness as disruption warning signals. For a limited set of NSTX discharges, a local island power balance criteria was found to be less reliable, presently, than the Greenwald limit. An empirical critical edge line density and a boundary turbulent transport limit were both tested for MAST-U, which has an electron density profile measurement with high spatial resolution in the outer part of the plasma. Both were found to have similar dependencies on key plasma parameters. In a limited set of MAST-U discharges that appear to disrupt due to rising density at values under the Greenwald limit, crossing of the boundary turbulent transport limit occurred close to the time of disruption. Finally, these limits were evaluated for their potential use in real-time, and it was found that with the necessary real-time inputs and with refinement through further testing, these limits could be implemented in a real-time disruption forecasting system.
Bioinspired design of stimuli-responsive artificial muscles with multiple actuation modes
Authors: Yang Huxiao , Zhang Chao , Chen Baihong , Wang Zhijian , Xu Yan , Xiao Rui 
Published: July 2023

Abstract
Artificial muscles that can reproduce the functions and biomimetic motions of natural muscles are widely used to construct soft robots with applications in various fields. However, it is still challenging to develop stimuli-responsive artificial muscles with multiple-mode actuation. Inspired by the forearm muscles, we propose a new type of stimuli-responsive artificial muscles with multiple-mode actuation using liquid crystal elastomers (LCEs), named FILAMs (forearm muscle-inspired LCE-based artificial muscles). The proposed FILAMs consist of active LCE driving units, a passive silicone rubber flexible skeleton and two quick connectors. By selectively actuating different types of LCE driving units, the FILAMs can achieve multiple-mode actuation, such as twisting, bending, combined twisting and bending. We introduce prototypical designs for the FILAMs and demonstrate that they can be used as ‘building blocks’ to reconfigure different soft robots. Three kinds of soft robots are constructed to show extensive applications through the cooperation of a combination FILAMs, i.e. a soft assembly robot, a soft crawling robot, and a soft flexible wrist.