Progress in the Study of Vortex Pinning Centers in High-Temperature Superconducting Films

Since the discovery of high-temperature superconductors (HTSs), significant progress in the fabrication of HTS films has been achieved. In this review, we intend to provide an overview of recent progress in how and why superconductivity can be enhanced by introducing nanoscale vortex pinning centers. The comprehensive control of morphology, dimension, orientation and concentration of artificial pinning centers (APCs) and the principle of vortex pinning are the focus of this review. According to the existing literature, HTSs with the best superconductivity can be obtained when one-dimensional (1D) and three-dimensional (3D) nanoscale APCs are combined for vortex pinning

A Review on Strain Study of Cuprate Superconductors

Cuprate superconductors have attracted extensive attention due to their broad promising application prospects. Among the factors affecting superconductivity, the effect of strain cannot be ignored, which can significantly enhance or degrade superconductivity. In this review, we discuss and summarize the methods of applying strain to cuprate superconductors, strain measurement techniques, and the influence of strain on superconductivity. Among them, we pay special attention to the study of strain in high–temperature superconducting (HTS) films and coating. We expect this review can guide further research in the field of cuprate superconductors

Excellent Microwave Absorption Properties Derived from the Synthesis of Hollow Fe₃o₄@Reduced Graphite Oxide (RGO) Nanocomposites

Magnetic nanoparticles, such as Fe3O4 and Co3O4, play a vital role in the research on advanced microwave absorbing materials, even if problems such as high density and narrow band impedance matching are still unsolved. Herein, the study of lightweight hollow Fe3O4@reduced graphite oxide (RGO) nanocomposites synthesized via the solvothermal method is presented. The microstructure and crystal morphology of the materials were characterized by X-ray diffractometer (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) analyses. Single crystalline hollow Fe3O4 spheres were grown onto RGO flakes, leading to the formation of heterojunction, which further influenced the microwave absorption properties. The latter were evaluated by standard microwave characterization in the frequency range of 2⁻18 GHz. It was found that, for a specific [email protected] g RGO composite, the minimum reflection loss can reach −41.89 dB at 6.7 GHz, while the reflection loss was less than −10 dB from 3.4 GHz to 13.6 GHz for a nanocomposite sample thickness in the range of 1⁻4 mm. The combination of these two materials thus proved to give remarkable microwave absorption properties, owing to enhanced magnetic losses and favorable impedance matching conditions

Fabrication and Enhanced Supercapacitive Performance of Fe2N@Cotton-based Porous Carbon fibers as Electrode Material

With the emergence of supercapacitors (SCs), the creation of bio-based electrode materials has grown in significance for the advancement of energy storage. However, it is particularly difficult for cathode materials to meet the demands of practical uses due to their low energy density. Herein, MIL-88 was fabricated in situ on the surface of cotton fibers used in cosmetics, followed by creating Fe2N@porous carbon fiber composite (Fe2N@PCF) through heat treatment at various temperatures. Fe2N@PCF-800 demonstrates excellent specific capacitance performance (552 F g−1 at 1 A g−1). Meanwhile, The AC//Fe2N@PCF-800 device exhibits the largest energy density of 38 Wh kg−1 at 800 W kg−1 and a long cycling stability (83.3% capacity retention after 6000 cycles). Our elaborately designed Fe2N@PCF demonstrate multiple advantages: i) the Fe2N@PCF-800 shows abundant mesopores, providing abundant ion-diffusion pathways for mass transport and rich graphite microstructures, improving electrical conductivity for electron transferowning; ii) the rich nitrogen dopants and Fe2N structure within all carbon components increase the capacitance through their pseudocapacitive contribution. These findings highlight the importance of biomass derived carbon materials for SCs applications

The Effect of Exposure to a High-Fat Diet on MicroRNA Expression in the Liver of Blunt Snout Bream (<i>Megalobrama amblycephala</i>)

<div><p>Blunt snout bream (<i>Megalobrama amblycephala</i>) are susceptible to hepatic steatosis when maintained in modern intensive culture systems. The aim of this study was to investigate the potential roles of microRNAs (miRNAs) in diet-induced hepatic steatosis in this species. MiRNAs, small non-coding RNAs that regulate gene expression at the posttranscriptional level, are involved in diverse biological processes, including lipid metabolism. Deep sequencing of hepatic small RNA libraries from blunt snout bream fed normal-fat and high-fat diets identified 202 (193 known and 9 novel) miRNAs, of which 12 were differentially expressed between the normal-fat and high-fat diet groups. Quantitative stem-loop reverse transcriptase-polymerase chain reaction analyses confirmed the upregulation of miR-30c and miR-30e-3p and the downregulation of miR-145 and miR-15a-5p in high-fat diet-fed fish. Bioinformatics tools were used to predict the targets of these verified miRNAs and to explore potential downstream gene ontology biological process categories and Kyoto Encyclopedia of Genes and Genomes pathways. Six putative lipid metabolism-related target genes (fetuin-B, Cyp7a1, NADH dehydrogenase (ubiquinone) 1 beta subcomplex subunit 2, 3-oxoacid CoA transferase 1b, stearoyl-CoA desaturase, and fatty-acid synthase) were identified as having potential important roles in the development of diet-induced hepatic steatosis in blunt snout bream. The results presented here are a foundation for future studies of miRNA-controlled lipid metabolism regulatory networks in blunt snout bream.</p></div

Predicted lipid metabolism-related miRNA target genes that were regulated by exposure to a high-fat diet.

<p>Schematic representation of potential determinants of the pathogenesis of hepatic steatosis in blunt snout bream.</p

The ten most abundant miRNAs in the normal-fat diet (NFD) and high-fat diet (HFD) groups.

<p>The charts show the frequencies of the known miRNAs identified in the NFD (A) and HFD (B) groups.</p

Hepatic lipid accumulation in blunt snout bream fed a normal-fat diet (NFD) or high-fat diet (HFD).

<p>Photomicrographs (×400) of liver tissue samples from blunt snout bream fed a NFD (A) or HFD (B) for eight weeks. Scale bar, 50 µm.</p