High-performance biobased polyesters with excellent thermal, mechanical, and gas barrier properties are in demand nowadays, while current design strategies have failed to endow polyesters with such integrated performances synchronously. Herein, we synthesize a series of furan-based copolyesters poly(butylene 4-hydroxy-N-(2-hydroxyethyl)2,5-furandicarboxylate) (PBA n F) containing an amide structure and flexible aliphatic segments in the main chains via condensed polymerization. The resultant copolyester PBA20F records balanced pre-eminent mechanical properties including tensile strength (78.0 MPa) and a large elongation at break (199%) while exhibiting a high glass transition temperature (54 °C) and a good enough gas barrier property. Such integrated excellent performances of copolyesters are ascribed to the combined effects of introduced intermolecular hydrogen bonds and flexible segments. Besides, PBA n Fs still display high optical transparency in the visible region. This work provides an innovative design strategy to prepare a new class of advanced furan-based copolyesters with remarkable mechanical, thermal, and gas barrier properties, thus supplying a series of promising high-performance biobased copolyesters for potential packaging applications.

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Macula fovea localization has significant impact on retinal image analysis of particular macular diseases. This study proposes a macula fovea localization method based on wavelet transformation and gray contours. First, the modulus minimums are extracted by quadratic spline dyadic wavelet transformation without a down-sample; these are candidate locations of the macula fovea center. Next, the gray contour based on Gaussian-like grayscale distribution is structured for the accurate and effective detection of macula fovea. The test results obtained by analysis of 40 fundus images from the DRIVE database demonstrate 100% accuracy in macula fovea localization.

In order to study the buckling failure of lining delamination of thin-walled lined composite pipe, a numerical analysis model was established by using bilinear cohesion relationship, the buckling mode and critical load of the composite pipe obtained by linear buckling are taken as reference values, the interlayer initial defects were introduced to carry out the nonlinear buckling analysis on the composite pipe lining structure with thin wall lining. The relative displacement curve and deformation morphology of the relative displacement of the lining with the change of external pressure were obtained, and the results are consistent with the existing test results. Based on this model, the buckling sensitivity of lining pipe was analyzed. The results show that the size of interlayer initial defect is the main factor that affects the critical buckling pressure of liner, but it has little influence on the propagation pressure after buckling; However, the increase of interlayer bonding effect significantly improves the buckling resistance and propagation pressure of lining pipe; The ratio of outer tube wall diameter to thickness and liner thickness have significant effects on the critical buckling pressure of liner. The research results provide a reference for determining the interlayer bonding effect and the optimal design of the minimum thickness of the inner liner.