bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ultraviolet photodetector based on RbCu2I3 microwire
Authors: An Hong-Xiang , Qiao Bao-Shi , Zhang Zhi-Hong , Lian Zhen-Dong , Wei Zhipeng , Li Xiao-Shuang , Zeng Qing-Guang , Wang Bo , Ng Kar Wei , Wang Shuang-Peng 
Published: January 2023

Abstract
Copper-based halide perovskites have shown great potential in lighting and photodetection due to their excellent photoelectric properties, good stability and lead-free nature. However, as an important piece of copper-based perovskites, the synthesis and application of RbCu2I3 have never been reported. Here, we demonstrate the synthesis of high-quality RbCu2I3 microwires (MWs) by a fast-cooling hot saturated solution method. The prepared MWs exhibit an orthorhombic structure with a smooth surface. Optical measurements show the RbCu2I3 MWs have a sharp ultraviolet absorption edge with 3.63 eV optical band gap and ultra-large stokes shift (300 nm) in photoluminescence. The subsequent photodetector based on a single RbCu2I3 MW shows excellent ultraviolet detection performance. Under the 340 nm illumination, the device shows a specific detectivity of 5.0 × 109 Jones and a responsivity of 380 mA·W−1. The synthesis method and physical properties of RbCu2I3 could be a guide to the future optoelectronic application of the new material.
Ultrafast high-temperature sintering and thermoelectric properties of n-doped Mg2Si
Authors: Boldrini Stefano , Ferrario Alberto , Fasolin Stefano , Miozzo Alvise , Barison Simona 
Published: January 2023

Abstract
Ultrafast high-temperature sintering (UHS) is a recently proposed technique able to synthesize and sinter dense materials within seconds. Although UHS has already proved its effectivity with a large set of materials, spanning from refractory ceramics to complex metal alloys, any application to thermoelectric materials is today still lacking. Mg2Si is a well-established thermoelectric material. It is based on wide available non-critical raw materials, it is non-toxic, lightweight and it expresses its best thermoelectric performances in the intermediate temperature range (up to about 600 °C). Mg2Si is typically produced with powder processing by Spark Plasma Sintering (SPS), partially limiting its widespread diffusion also due to the costly production technique. Here we present a simple route to sinter Mg2Si pressed powders by UHS. The process allowed to obtain dense samples (with relative densities >95%) with 20 s heating up to about 1080 °C followed by a rapid free cooling, a total thermal history below 1 min, and with energy demand at the Wh scale. The high process rate proved its efficacy in preventing grain growth and in avoiding any significant Mg evaporation. A full thermoelectric functional characterization is presented for Mg2Si and Bi-doped Mg2Si, together with a comparison with SPS-produced properties.
Agglomerated serum albumin adsorbed protocatechuic acid coated superparamagnetic iron oxide nanoparticles as a theranostic agent
Authors: Bozoglu Serdar , Arvas Melih Besir , Varlı Hanife Sevgi , Ucar Burcu , Acar Tayfun , Karatepe Nilgün 
Published: January 2023

AbstractIron oxide nanoparticles have been one of the most widely used nanomaterials in biomedical applications. However, the incomplete understanding of the toxicity mechanisms limits their use in diagnosis and treatment processes. Many parameters are associated with their toxicity such as size, surface modification, solubility, concentration and immunogenicity. Further research needs to be done to address toxicity-related concerns and to increase its effectiveness in various applications. Herein, colloidally stable nanoparticles were prepared by coating magnetic iron oxide nanoparticles (MIONPs) with protocatechuic acid (PCA) which served as a stabilizer and a linkage for a further functional layer. A new perfusion agent with magnetic imaging capability was produced by the adsorption of biocompatible passivating agent macro-aggregated albumin (MAA) on the PCA-coated MIONPs. PCA-coated MIONPs were investigated using infrared spectroscopy, thermogravimetric analysis and dynamic light scattering while adsorption of MAA was analysed by transmission electron microscopy, Fourier-transform infrared spectroscopy and x-ray diffraction methods. Magnetic measurements of samples indicated that all samples showed superparamagnetic behaviour. Cytotoxicity results revealed that the adsorption of MAA onto PCA-coated MIONPs provided an advantage by diminishing their toxicity against the L929 mouse fibroblast cell line compared to bare Fe3O4.
Topologically preserved registration of 3D CT images with deep networks
Authors: Liu Huaying , Gong Guanzhong , Zou Wei , Hu Nan , Wang Jiajun 
Published: January 2023

Abstract

Objective. Computed Tomography (CT) image registration makes fast and accurate imaging-based disease diagnosis possible. We aim to develop a framework which can perform accurate local registration of organs in 3D CT images while preserving the topology of transformation. Approach. In this framework, the Faster R-CNN method is first used to detect local areas containing organs from fixed and moving images whose results are then registered with a weakly supervised deep neural network. In this network, a novel 3D channel coordinate attention (CA) module is introduced to reduce the loss of position information. The image edge loss and the organ labelling loss are used to weakly supervise the training process of our deep network, which enables the network learning to focus on registering organs and image structures. An intuitive inverse module is also used to reduce the folding of deformation field. More specifically, the folding is suppressed directly by simultaneously maximizing forward and backward registration accuracy in the image domain rather than indirectly by measuring the consistency of forward and inverse deformation fields as usual. Main results. Our method achieves an average dice similarity coefficient (DSC) of 0.954 and an average Similarity (Sim) of 0.914 on publicly available liver datasets (LiTS for training and Sliver07 for testing) and achieves an average DSC of 0.914 and an average Sim of 0.947 on our home-built left ventricular myocardium (LVM) dataset. Significance. Experimental results show that our proposed method can significantly improve the registration accuracy of organs such as the liver and LVM. Moreover, our inverse module can intuitively improve the inherent topological preservation of transformations.
Cross-convolutional transformer for automated multi-organs segmentation in a variety of medical images
Authors: Wang Jing , Zhao Haiyue , Liang Wei , Wang Shuyu , Zhang Yan 
Published: January 2023

Abstract

Objective. It is a huge challenge for multi-organs segmentation in various medical images based on a consistent algorithm with the development of deep learning methods. We therefore develop a deep learning method based on cross-convolutional transformer for these automated- segmentation to obtain better generalization and accuracy. Approach. We propose a cross-convolutional transformer network (C2Former) to solve the segmentation problem. Specifically, we first redesign a novel cross-convolutional self-attention mechanism in terms of the algorithm to integrate local and global contexts and model long-distance and short-distance dependencies to enhance the semantic feature understanding of images. Then multi-scale feature edge fusion module is proposed to combine the image edge features, which effectively form multi-scale feature streams and establish reliable relational connections in the global context. Finally, we use three different modalities, imaging three different anatomical regions to train and test multi organs and evaluate segmentation performance. Main results. We use the evaluation metrics of Dice similarity coefficient (DSC) and 95% Hausdorff distance (HD95) for each dataset. Experiments showed the average DSC of 83.22% and HD95 of 17.55 mm on the Synapse dataset (CT images of abdominal multi-organ), the average DSC of 91.42% and HD95 of 1.06 mm on the ACDC dataset (MRI of cardiac substructures) and the average DSC of 86.78% and HD95 of 16.85 mm on the ISIC 2017 dataset (skin cancer images). In each dataset, our proposed method consistently outperforms the compared networks. Significance. The proposed deep learning network provides a generalized and accurate solution method for multi-organ segmentation in the three different datasets. It has the potential to be applied to a variety of medical datasets for structural segmentation.
The effect of longitudinal static magnetic field on the radiation efficiency of high harmonics from overdense plasma
Authors: Wu Yanbo , Xu Xinrong , Li Qianni , Zou Debin , Zhang Yuxue , Yin Yan , Liu Ke , Yu TongPu 
Published: January 2023

Abstract
The effect of the magnetic field applied along the laser propagation direction on the radiation efficiency of high-order harmonics generated from laser-irradiated overdense plasma is investigated theoretically and numerically. We find that the external magnetic field can increase the transmittance of the overdense target, thereby dramatically enhancing the energy coupling between the laser and target. While for high-order harmonics of the laser reflected from the oscillating target, the radiation efficiency reaches the maximum when the cyclotron frequency of the electrons in the magnetized target approaches the laser frequency. This conclusion applies only to overdense plasmas targets. For targets with low reflectivity, the application of the magnetic field reduces the harmonic radiation efficiency due to the decrease of both the oscillating coherence and opacity of the target. This work provides a reasonable approach to improving the radiation efficiency of high-order harmonics and a method to estimate the magnitude of the self-generated magnetic field during intense laser–plasma interactions.
Nonlinear second order electromagnetic gyrokinetic theory for a tokamak plasma
Authors: Dudkovskaia A V , Wilson H R , Connor J W , Dickinson D , Parra F I 
Published: January 2023

Abstract
The steep plasma pressure gradient that forms at the edge of the high confinement, H-mode regime of tokamak operation provides free energy to drive electromagnetic micro-instabilities that are widely believed to influence the transport processes in this so-called pedestal region. This high pressure gradient also provides a high current density (bootstrap current), known to influence ballooning mode stability and to be important for driving kink modes in the ideal magneto-hydrodynamic plasma model (so-called peeling-ballooning modes). Furthermore, efficient, steady state future tokamak power plants must operate with a large bootstrap current in the core and especially concerning spherical tokamaks, confinement will be influenced by electromagnetic turbulence. To accommodate these important situations, conventional electromagnetic gyrokinetic theory is extended to incorporate neoclassical effects in the equilibrium drives, allowing

B

ϑ

∼

B
0

(B
0 is the confining magnetic field, and B

ϑ
is its poloidal component). This provides a global gyrokinetic model that self-consistently captures the consequences of large bootstrap current fractions on the equilibrium distribution functions.
Hyperdoped silicon materials: from basic materials properties to sub-bandgap infrared photodetectors
Authors: Sher Meng-Ju , Hemme Eric García 
Published: January 2023

Abstract
Hyperdoping silicon, which introduces deep-level dopants into Si at concentrations near one atomic percent, drastically changes its optoelectronic properties. We review recent progress in the fundamental understanding of the material properties and state of the art sub-bandgap infrared photodetectors. Different hyperdoping techniques are reviewed and compared, namely ion implantation followed by pulsed laser melting (PLM) or other fast annealing methods and PLM of Si with a dopant precursor. We review data available in the literature for material properties related to the success of optoelectronic devices such as the charge carrier lifetime, mobility, and sub-bandgap light absorption of hyperdoped Si with different dopants. To maximize carrier generation and collection efficiency in a sub-bandgap photodetector, charge carrier lifetimes must be long enough to be transported through the hyperdoped layer, which should be on the order of light absorption depth. Lastly, the charge transport properties and photodetector responsivities of hyperdoped Si based photodiodes at room temperature and at cryogenic temperatures are compared. The charge carrier transport mechanisms at different temperature ranges and in different dopant systems are discussed. At room temperature, despite different dopant energetics and hyperdoped thicknesses, light detection exhibits similar spectral responsivities with a common cutoff around 0.5 eV, and at low temperatures, it extends further into the infrared range. The roles of the dopant energetics and process-induced defects are discussed. We highlight future material development directions for enhancing device performance.
Fabrication, characterization, and gas sensing performance of chromium doped WO3 nanoflakes
Authors: Kılıç Alp , Tekin Büşra , Alev Onur , Özdemir Okan , Colakerol Arslan Leyla , Büyükköse Serkan , Özturk Zafer Ziya 
Published: January 2023

Abstract
Pristine and chromium (Cr) doped WO3 nanoflakes (NFs) with various concentrations were successfully fabricated by a facile hydrothermal technique on alumina (Al2O3) substrates. The structural, optical, and morphological properties of these NFs were investigated by x-ray diffraction, scanning electron microscopy, transmission electron microscopy, UV-Visible diffusion reflectance spectroscopy (UV–Vis DRS), and x-ray photoelectron spectroscopy. Gas sensor tests were performed against various volatile organic compounds such as ethanol, xylene, toluene, and isopropanol gases in the temperature range between 50 °C and 250 °C. According to the results of these tests, the isopropanol sensing ability of WO3 NFs is enhanced with Cr-doping due to the increasing active adsorption sites on the surface and improved surface reactions with the decreasing band gap energy. The highest isopropanol sensing response which was calculated to be 77.1 has been obtained by nominally 2% Cr doping at the optimal operating temperature of 150 °C.
Theoretical and experimental study on performance of compound-driven MR valve-controlled damper
Authors: Sun Anxin , Xie Fangwei , Yu Xinshi , Shi Xiuwei , Ji Jinjie , Gao Yonghua , He Kewei 
Published: January 2023

Abstract
A compound-driven magnetorheological (MR) valve is designed to cope with the low reliability and high energy consumption of traditional MR valves. The operating magnetic field of the valve is applied by both the excitation coil and ring magnet, maintaining excellent pressure drop performance even at zero current. To analyze the performance and obtain the variation law of the magnetic flux density and pressure drop, a pressure drop mathematical model and a magnetic field simulation model are established. The key parameters of the MR valve are also optimized using non-dominated sorting genetic algorithms-II. A dynamic performance test system is built, and the influence of the load on the pressure drop and hysteresis characteristics of the MR valve is studied. The results show that the optimized pressure drop and adjustable coefficient are improved by 4.7% and 8.6% respectively. The pressure drop grows nonlinearly with the electric current and reaches saturation at a current of 1.5 A, and a pressure drop of 1485 kPa is still generated at zero current. The output damping force of the compound-driven MR valve-controlled damper can be continuously adjustable, indicating that the dynamic performance of the damper can be controlled by adjusting the input current.
A theoretical study of the improved CO oxidation on WC supported Au monolayer by Cu doping
Authors: Chang Qingfang , Zhang Xilin , Yang Zongxian 
Published: January 2023

Abstract
Metal monolayer supported on tungsten carbides have received considerable attention in the field of catalysis, while the adsorption properties of reactants need to be optimized to improve the catalytic activity further. Alloy monolayers on tungsten carbides can deliver different geometric and electronic characters from pure metal layers, owing to the change in local environments. Herein, using the first-principles calculations, the CO oxidation processes on the supported CuAu alloy monolayer on tungsten carbide are systematically investigated and compared with that on pure metal monolayers. It is found that introducing Cu dopant in Au monolayer will elevate the d-band center of the formed alloy monolayer and thus enhancing the adsorption of reactants around the Cu atom, which is caused by the charge redistribution. Especially, the unbalanced interaction strength between Cu-O and Au-O promotes the rotation and migration of oxygen atom to interact with the C atom of CO, which lowers the energy barriers for the formation and dissociation of OOCO intermediate. The oxidation of CO by an atomic O with the largest energy barrier of 0.27 eV along the Langmuir-Hinshelwood pathway is identified as the rate determining step, which is superior or comparable to the reported CO oxidation catalysts. The significance of alloy monolayer on tungsten carbides are further highlighted by comparing the adsorption energy and reaction barrier of rate-limiting step on the pure metal monolayers. This work is insightful for the rational design of highly efficient catalysts based on alloy systems.
Simulation of bulk and grain boundary diffusion phenomena in a high entropy CoCrFeMnNi alloy by molecular dynamics
Authors: Junhong Fan , Weiqiang Zhang 
Published: January 2023

Abstract
A series of calculations on the self-diffusion behavior of high entropy CoCrFeMnNi alloy were carried out using molecular dynamics methods. By computing both vacancy formation energy and atomic migration energy of the constituent elements in the alloy, the diffusional activation energy of each element is obtained, and the self-diffusion coefficients for bulk diffusion were calculated, with the values exhibiting close to of experiments. A model for structures of symmetrically tilted grain boundary is established, with Σ9 and Σ27 grain boundaries studied based on the coincidence site lattice theory. Measured by the full width at half maxima of the radial distribution function, it is found that the grain boundaries with low index are more ordered than those with high plane index, and the atom fluctuation occurred in the low-indexed grain boundaries is less intensively and sensitively to temperature change. Meanwhile, the diffusion coefficients of ordered grain boundaries are generally smaller than those of disordered grain boundaries. Compared with the experimental values of grain boundary diffusion, the diffusion activation energy of configured grain boundaries from coincidence site lattice is smaller than that of normal large-angle grain boundaries.
Correlation between speed and turning naturally arises for sparsely sampled cell movements
Authors: Ganusov Vitaly V , Zenkov Viktor S , Majumder Barun 
Published: January 2023

Abstract
Mechanisms regulating cell movement are not fully understood. One feature of cell movement that determines how far cells displace from an initial position is persistence, the ability to perform movements in a direction similar to the previous movement direction. Persistence is thus determined by turning angles (TA) between two sequential displacements and can be characterized by an average TA or persistence time. Recent studies documenting T cell movement in zebrafish found that a cell’s average speed and average TA are negatively correlated, suggesting a fundamental cell-intrinsic program whereby cells with a lower TA (and larger persistence time) are intrinsically faster (or faster cells turn less). In this paper we confirm the existence of the correlation between turning and speed for six different datasets on 3D movement of CD8 T cells in murine lymph nodes or liver. Interestingly, the negative correlation between TA and speed was observed in experiments in which liver-localized CD8 T cells rapidly displace due to floating with the blood flow, suggesting that other mechanisms besides cell-intrinsic program may be at play. By simulating correlated random walks using two different frameworks (one based on the von Mises–Fisher (vMF) distribution and another based on the Ornstein–Uhlenbeck (OU) process) we show that the negative correlation between speed and turning naturally arises when cell trajectories are sub-sampled, i.e. when the frequency of sampling is lower than frequency at which cells typically make movements. This effect is strongest when the sampling frequency is of the order of magnitude of the inverse of persistence time of cells and when cells vary in persistence time. The effect arises in part due to the sensitivity of estimated cell speeds to the frequency of imaging whereby less frequent imaging results in slower speeds. Interestingly, by using estimated persistence times for cells in two of our datasets and simulating cell movements using the OU process, we could partially reproduce the experimentally observed correlation between TA and speed without a cell-intrinsic program linking the two processes. Our results thus suggest that sub-sampling may contribute to (and perhaps fully explains) the observed correlation between speed and turning at least for some cell trajectory data and emphasize the role of sampling frequency in the inference of critical cellular parameters of cell motility such as speeds.
Five-year Monitoring of 225 GHz Opacity at Thule Air Base (Pituffik), Greenland
Authors: Matsushita Satoki , Martin-Cocher Pierre L. , Paine Scott N. , Huang Chih-Wei L. , Patel Nimesh A. , Asada Keiichi , Chen Ming-Tang , Ho Paul T. P. , Inoue Makoto , Koch Patrick M. , Norton Timothy 
Published: January 2023

Abstract
We present five-year monitoring results of 225 GHz zenith opacity using a tipping radiometer at Thule Air Base (Pituffik), Greenland, where the Greenland Telescope is currently located. The site shows a clear seasonal variation with average opacity lower by a factor of two during winter compared with summer, similar to Greenland Summit. The 25%, 50%, and 75% quartiles of the 225 GHz opacity during the winter months of November through April are 0.14, 0.17, and 0.22, respectively. These values are three times larger than those at the Greenland Summit, and the astronomical observing efficiency in this band is about an order of magnitude better at the Summit than at the Thule Air Base. 225 GHz opacity continuously less than 0.2 for 100–200 hr (i.e., for about a week) occurs about 20 times per year, and on several occasions it even reaches up to 300–400 hr (i.e., about two weeks). These statistics indicate that Thule is a very good site for millimeter astronomy that needs very stable opacity conditions, such as continuum camera observations or VLBI observations that span over several days. Estimated transmission spectra in the winter season show that most of the time (75% quartile) observations at frequencies below 300 GHz are possible with modest atmospheric attenuation (opacities < 0.5), and at frequencies below 350 GHz for a quarter of the time. Although the atmospheric transmission is low (only up to ∼20%), the 650 GHz and 850 GHz windows are also accessible for 5% of the wintertime. For about 50% of the summertime, it is possible to observe around the frequency of 220 GHz, which overlaps with the current EHT observation frequency of 221.1 GHz, with modest atmospheric attenuation (opacities < 0.5). On the other hand, the 350 GHz window is very difficult to observe in the summertime.