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The primary objective of this study is the development of Cu/Nb composite materials for Superconducting Radio-Frequency (SRF) applications under extreme service conditions characterized by a strong RF electromagnetic field, extremely low temperatures, and relatively low heat loss. A novel integrated manufacturing approach is proposed, which combines cold-sprayed AgCuTi alloy as an intermediate coating on the Nb surface and an electroplated Cu layer with a subsequent heat treatment brazing effect. This strategy aims to address the significant challenge of non-intermelting Cu and Nb while also considering effective lateral heat transfer. Mechanical property tests showed that the bond strength of Nb/AgCuTi/Cu composites exceeded 150 MPa. Low-temperature thermal transport tests indicate that the Residual Resistance Ratio (RRR) of the Cu layer surpasses 150, with a thermal conductivity at 4.2 K exceeding 1600 W/(m·K). Moreover, both the composite interface and mechanical properties of the specimens remain stable even after undergoing cyclic cold shock experiments. These findings suggest that the Nb/AgCuTi/Cu composite material developed in this study meets the technical requirements for long-term stable and high-performance operation in high-current and high-power superconducting accelerators.

Actor-critic based online reinforcement learning control has been proved to be promising method for control of aerial vehicles. However, it is difficult to guarantee high-level success rate of initial training and to tune the large amount of parameters for actors and critics considering unstable multi-input and multi-output (MIMO) aircraft. In order to facilitate and simplify the training of the actor and critic for unstable aircraft, classic stability augmentation system (SAS) is designed for the open-loop aircraft first. Then the online incremental model based dual heuristic dynamic programming (IDHP) method, which has been proposed recently, is extended in application to design a multi-channel robust adaptive controller, and MIMO form network structures are designed and determined for the actors and critics considering the three-channel coupling issues. Consequently, the classic SAS and the IDHP controller make up a novel hybrid control framework. In this control framework, the SAS takes charge of counteracting the unstable eigenvalues of the open-loop aircraft system, and the IDHP takes charge on guaranteeing robust and adaptive performance for high-performance tailless aircraft equipped with the SAS. Specifically, the introduction of the classic control method decreases the difficulty of the initial training for multi-channel IDHP controller. The tuning process for initial parameters of actor and critic neural networks in multiple channels is greatly facilitated. Without the help of SAS, the initial training for multi-channel IDHP controllers of unstable plants is almost impossible to succeed. Finally, the novel hybrid control architecture and method are validated using the Innovative Control Effectors (ICE) model, which has unstable modes in the longitudinal dynamics. Typical aerodynamic model uncertainties are numerically simulated to demonstrate the effectiveness of the proposed control method.

BackgroundIdiopathic pulmonary fibrosis (IPF) is a fatal disease of unknown etiology with a poor prognosis, characterized by a lack of effective diagnostic and therapeutic interventions. The role of immunity in the pathogenesis of IPF is significant, yet remains inadequately understood. This study aimed to identify potential key genes in IPF and their relationship with immune cells by integrated bioinformatics analysis and verify by in vivo and in vitro experiments.MethodsGene microarray data were obtained from the Gene Expression Omnibus (GEO) for differential expression analysis. The differentially expressed genes (DEGs) were identified and subjected to functional enrichment analysis. By utilizing a combination of three machine learning algorithms, specific genes associated with idiopathic pulmonary fibrosis (IPF) were pinpointed. Then their diagnostic significance and potential co-regulators were elucidated. We further analyzed the correlation between key genes and immune infiltrating cells via single-sample gene set enrichment analysis (ssGSEA). Subsequently, a single-cell RNA sequencing data (scRNA-seq) was used to explore which cell types expressed key genes in IPF samples. Finally, a series of in vivo and in vitro experiments were conducted to validate the expression of candidate genes by western blot (WB), quantitative real-time PCR (qRT-PCR), and immunohistochemistry (IHC) analysis.ResultsA total of 647 DEGs of IPF were identified based on two datasets, including 225 downregulated genes and 422 upregulated genes. They are closely related to biological functions such as cell migration, structural organization, immune cell chemotaxis, and extracellular matrix. CFH and FHL2 were identified as key genes with diagnostic accuracy for IPF by three machine learning algorithms. Analysis using ssGSEA revealed a significant association of both CFH and FHL2 with diverse immune cells, such as B cells and NK cells. Further scRNA-seq analysis indicated CFH and FHL2 were specifically upregulated in human IPF tissues, which was confirmed by in vitro and in vivo experiments.ConclusionIn this study, CFH and FHL2 have been identified as novel potential biomarkers for IPF, with potential diagnostic utility in future clinical applications. Subsequent investigations into the functions of these genes in IPF and their interactions with immune cells may enhance comprehension of the disease’s pathogenesis and facilitate the identification of therapeutic targets.