Skyrmion-Bubble Bundles in an X-type Sr2Co2Fe28O46 Hexaferrite above Room Temperature

Magnetic skyrmions are spin swirls that possess topological nontriviality and are considered particle-like entities. They are distinguished by an integer topological charge Q. The presence of skyrmion bundles provides an opportunity to explore the range of values for Q, which is crucial for the advancement of topological spintronic devices with multi-Q properties. In this study, we present a new material candidate, Sr2Co2Fe28O46 hexaferrite of the X-type, which hosts small dipolar skyrmions at room temperature and above. By exploiting reversed magnetic fields from metastable skyrmion bubbles at zero fields, we can incorporate skyrmion-bubble bundles with different interior skyrmion/bubble numbers, topological charges, and morphologies at room temperature. Our experimental findings are consistently supported by micromagnetic simulations. Our results highlight the versatility of topological spin textures in centrosymmetric uniaxial magnets, thereby paving the way for the development of room-temperature topological spintronic devices with multi-Q characteristics.Comment: https://doi.org/10.1002/adma.20230611

Evaluation of oral Lanzhou lamb rotavirus vaccine via passive transfusion with CD4+/CD8+ T lymphocytes

AbstractLanzhou Lamb derived Rotavirus (RV) Vaccine (namely LLR) for children is only used in China. Since there were no reports on evaluation of LLR, even the data of phase IV clinical trial, we proceed the evaluation of LLR through focusing on T-cell to investigate whether LLR could induce the potential function involving in protection as a vaccine. Four groups of nude mice were transfused with CD4+/CD8+ T-cells isolated from LLR-immunized (primed) and LLR-unimmunized (naïve) mice via intraperitonea (i.p.) respectively. Consequently, the adoption mice were challenged with mice-origin wild rotavirus EDIM (Epizootic Diarrhea of Infant Mice) by intragastric administration. Series of fecal/serum samples were collected and viral shedding, then serum IgA/IgG and secreted IgA were assayed. Compared to the mice transfused with T lymphocytes from naïve mice, the nude mice transfused with CD4+ T lymphocytes from primed mice induce fecal and serum IgA increasing more rapidly, and have a shorter duration of virus shedding too. Whereas, no significant difference in virus clearance was found between the mice transfused with CD8+ T lymphocytes isolated from primed and naïve mice. Therefore, we cleared the distinct roles of transfused CD4+/CD8+ T lymphocytes for rotavirus clearance in nude mice, that the viral clearance conducted by CD4+ T lymphocytes. Meanwhile, it has ability to help induction of LLR specific immunogenicity. Comparing with the transfusion of cell from primed and naïve mice, LLR can induce CD4+ T lymphocytes memory which is a potential index to reflect the immunogenicity and protection, while CD8+ T lymphocytes remove rotavirus by CTL with little memory ability

Observation of Hybrid Magnetic Skyrmion Bubbles in Fe3Sn2 Nanodisks

It is well known that there are two types of magnetic bubbles in uniaxial magnets. Here, using Lorentz-transimission electronic microscopy magnetic imaging, we report the direct experimental observation of 3D type-III hybrid bubbles, which comprise N\'eel-twisted skyrmion bubbles with topological charge Q = -1 in near-surface layers and type-II bubbles with Q = 0 in interior layers, in Fe3Sn2 nanodisks. Using the tilted magnetic field, we further show the controlled topological magnetic transformations of three types of bubbles in a confined ferromagnetic nanodisk. Our observations are well reproduced using micromagnetic simulations based on measured magnetic parameters. Our results advance fundamental classification and understanding of magnetic bubbles, which could propel the applications of three-dimensional magnetism.Comment: https://doi.org/10.1103/PhysRevB.107.17442

(2R,3S)-2-Benzyl-3-(2,3,4,6-tetra-O-acetyl-β-d-glucopyranos­yloxy)butanolide

The title compound, C25H30O12, which demonstrates a significant hepatoprotective effect, has comparable geometrical parameters to those of similar compounds. The absolute configuration of the title compound, viz. 2R,3S, was identified from the Flack parameter of 0.05 (17) and the Hooft parameter of 0.04 (6)

Current-Controlled Skyrmion Number in Confined Ferromagnetic Nanostripes

Skyrmions are vortex-like localized magnetic structures that possess an integer-valued topological index known as the skyrmion number or topological charge. Skyrmion number determines the topology-related emergent magnetism, which is highly desirable for advanced storage and computing devices. In order to achieve device functions, it is necessary to manipulate the skyrmion number in confined nanostructured geometries using electrical methods. Here, we report the reliable current-controlled operations for manipulating the skyrmion number through reversible topological transformations between skyrmion chains and stripe domains in confined Fe3Sn2 nanostripes. The results of micromagnetic simulations are successful in numerically reproducing our experiments and explaining them through the combined effect of current-induced Joule heating and magnetic hysteresis. These findings hold the potential to advance the development of topological spintronic devices.Comment: https://doi.org/10.1002/adfm.20230404

Real-time Monitoring for the Next Core-Collapse Supernova in JUNO

Core-collapse supernova (CCSN) is one of the most energetic astrophysical events in the Universe. The early and prompt detection of neutrinos before (pre-SN) and during the SN burst is a unique opportunity to realize the multi-messenger observation of the CCSN events. In this work, we describe the monitoring concept and present the sensitivity of the system to the pre-SN and SN neutrinos at the Jiangmen Underground Neutrino Observatory (JUNO), which is a 20 kton liquid scintillator detector under construction in South China. The real-time monitoring system is designed with both the prompt monitors on the electronic board and online monitors at the data acquisition stage, in order to ensure both the alert speed and alert coverage of progenitor stars. By assuming a false alert rate of 1 per year, this monitoring system can be sensitive to the pre-SN neutrinos up to the distance of about 1.6 (0.9) kpc and SN neutrinos up to about 370 (360) kpc for a progenitor mass of 30$M_{\odot}$ for the case of normal (inverted) mass ordering. The pointing ability of the CCSN is evaluated by using the accumulated event anisotropy of the inverse beta decay interactions from pre-SN or SN neutrinos, which, along with the early alert, can play important roles for the followup multi-messenger observations of the next Galactic or nearby extragalactic CCSN.Comment: 24 pages, 9 figure

Failure Mechanism and Effect of Nozzle Parameters on Abrasive Water Jet Rock Breaking

Abrasive Water Jet (AWJ) technology has vast application prospects in the assisted drill-blasting of tunnel excavation, with the advantages of fast-breaking speed, low tool wear, less dust, and good mobility. Nevertheless, AWJ technology has some limitations and shortcomings, such as the small effective fracturing range and parameter mismatch, which influence the fracturing effect of AWJ. To solve the abovementioned issues, it is necessary to study the failure mechanism of rock impacted by AWJ and nozzle parameter effects on rock fragmentation. Based on the coupling algorithm of Smooth Particle Hydrodynamics and Finite Element Method (SPH-FEM), in this research, the numerical model of AWJ impacting rock was established, and the result was verified with Computed Tomography (CT) scanning after the AWJ impacting rock experiment and image processing technology. Through the analysis of the stress characteristics of typical particles in the rock model at different stages and positions, the formation and expansion mechanisms of the crater and the cracks were revealed. Additionally, in this research, the comprehensive damage factor of rock (X) representing the fragmentation degree was defined. By comparatively analyzing X-values with certain technical parameters of AWJ, the importance ranking of the nozzle parameters, the effect of each nozzle parameter on the rock fragmentation, and the optimal parameter combination were also investigated

BCCC Disjoint Path Construction Algorithm and Fault-Tolerant Routing Algorithm under Restricted Connectivity

Connectivity in large-scale data center networks is a critical indicator to evaluate network state. A feasible and performance-guaranteed algorithm enables us to find disjoint paths between network vertices to ensure effective data transfer and to maintain the normal operation of network in case of faulty nodes. As an important data center network, BCube Connected Crossbars (BCCC) has many excellent properties that have been widely studied. In this paper, we first propose a vertex disjoint path algorithm with the time complexity of O(nk) in BCCC, where n denotes a switch connected to n servers and k denotes dimension. Then, we prove that the restricted connectivity of BCCC(n,k). Finally, we present an O(knκ1(G)) fault-free algorithm in BCCC, where κ1(G) is the restricted connectivity. This algorithm can obtain a fault-free path between any two distinct fault-free vertices under the condition that each vertex has at least one fault-free neighbor in the BCCC and a set of faulty vertices F with |F|κ1(G)

A sentence-level text adversarial attack algorithm against IIoT based smart grid

With the development of data processing technologies, efficiency of information processing in the Industrial Internet of Things (IIoT) is greatly improved. In this situation solving the following security problems of the IIoT is the top priority. In IIoT based smart grid, through Natural Language Processing (NLP) technology various types of text data such as the equipment status and historical records can be better utilized. While bringing great help to the extraction of useful information, NLP technology also raises security concerns. In this paper, we present how text adversarial attacks can cause security problems in IIoT based smart grid, which may lead to serious consequences in some scenarios. Specifically, we develop the Important Sentences Perturbed and Encoder/Decoder (ISPED), a novel text adversarial attack algorithm for natural language classification models on the sentence-level. We select sentences that have more influence on the results to disturb while keeping the semantics basically unchanged to reduce smart grid workers’ perception of the attack. Experiments on different datasets and models show that our attacking method can effectively reduce the classification accuracy. Meanwhile, by comparing the original examples with the adversarial examples, we demonstrate that the semantics of the examples remain basically the same.The work is partially supported by the National Natural Science Foundation of China under grant 61972148 and the Fundamental Research Funds for the Central Universities under grant 2019MS020