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The fused deposition molding (FDM) process is a 3D printing molding process that has received extensive attention and research because of its free molding, strong designability and rapid prototyping. This further expands the application of continuous fiber reinforced composites. This paper reviews the forming principle, process method, equipment and printing materials of the FDM process for continuous fiber reinforced composites. The effects of process parameters, impregnation state and path planning algorithm on the mechanical properties and surface quality of 3D printed continuous fiber reinforced composite samples are analyzed. The problems encountered in the current FDM process and technology development are summarized, and suggestions for the key directions of future development are proposed.

An intermolecular annulation reaction of 2‐aryl‐1,3‐indandions with alkynes was reported using Pd(OAc)2 to access spirobi[indene]‐1,3‐diones. Under palladium catalysis, the substrates form a homocoupling dimer intermediate through a catalytic dehydrogenative cross‐coupling process. The palladium(II) species could come from dimer or 2‐aryl‐1,3‐indandion. Notably, this pathway is not typically observed in enol‐directed formal sp3 C−H functionalization/oxidative annulation palladium chemistry. This transformation provides a route to access a class of functionalized spiro carbocyclic indenes. [ABSTRACT FROM AUTHOR]

Silk nanofibrils (SNFs), the fundamental building blocks of silk fibers, endow them with exceptional properties. However, the intricate mechanism governing SNF assembly, a process involving both protein conformational transitions and protein molecule conjunctions, remains elusive. This lack of understanding has hindered the development of artificial silk spinning techniques. In this study, we address this challenge by employing a graphene plasmonic infrared sensor in conjunction with multi-scale molecular dynamics (MD). This unique approach allows us to probe the secondary structure of nanoscale assembly intermediates (0.8–6.2 nm) and their morphological evolution. It also provides insights into the dynamics of silk fibroin (SF) over extended molecular timeframes. Our novel findings reveal that amorphous SFs undergo a conformational transition towards β-sheet-rich oligomers on graphene. These oligomers then connect to evolve into SNFs. These insights provide a comprehensive picture of SNF assembly, paving the way for advancements in biomimetic silk spinning. Here, the authors develop a graphene plasmonic infrared sensor to probe the secondary structure of nanoscale assembly intermediates and the morphological evolution of silk nanofibrils, the fundamental building blocks of silk fibres. [ABSTRACT FROM AUTHOR]

An electrochemically enabled tandem cyclization reaction of unsaturated sulfoximines with diselenides has been well developed, affording metal‐ and external oxidant‐free access to sulfoximidoyl‐based heterocycles containing selenium in moderate to good yields. With nBu4NBr as the role of catalyst and electrolyte, this methodology shows broad substrate scope and functional group tolerance under mild conditions. [ABSTRACT FROM AUTHOR]

In this paper, we propose a method that uses the idea of decoupling and unites edge information for semantic segmentation. We build a new dual-stream CNN architecture that fully considers the interaction between the body and the edge of the object, and our method significantly improves the segmentation performance of small objects and object boundaries. The dual-stream CNN architecture mainly consists of a body-stream module and an edge-stream module, which process the feature map of the segmented object into two parts with low coupling: body features and edge features. The body stream warps the image features by learning the flow-field offset, warps the body pixels toward object inner parts, completes the generation of the body features, and enhances the object's inner consistency. In the generation of edge features, the current state-of-the-art model processes information such as color, shape, and texture under a single network, which will ignore the recognition of important information. Our method separates the edge-processing branch in the network, i.e., the edge stream. The edge stream processes information in parallel with the body stream and effectively eliminates the noise of useless information by introducing a non-edge suppression layer to emphasize the importance of edge information. We validate our method on the large-scale public dataset Cityscapes, and our method greatly improves the segmentation performance of hard-to-segment objects and achieves state-of-the-art result. Notably, the method in this paper can achieve 82.6% mIoU on the Cityscapes with only fine-annotated data. [ABSTRACT FROM AUTHOR]

We report on the first, to the best of our knowledge, simultaneous continuous-wave red, green and blue laser operations in praseodymium-doped crystalline materials. At an absorbed pump power of 4.7 W (or 10 W of incident pump power), the maximum output power was 665 mW, which included 607 nm (red), 523 nm (green) and 479 nm (blue) three wavelengths, and the optical conversion efficiency with respect to the absorbed pump power was 14.1%. [ABSTRACT FROM AUTHOR]