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To study the effect of the finishing process on the mechanical properties of polybutylene terephthalate/polyethylene terephthalate (PBT/PET) bicomponent polyester fiber, PBT/PET yarns were subjected to heat-moisture and dry-heat treatment at different temperatures and times. The tensile properties, elastic recovery, stress relaxation, and creep properties of the yarn were tested. The crystalline structure of PBT/PET fiber before and after heat treatment was studied by X-ray diffraction (XRD) to explain the change in yarn mechanical properties. The mechanical model of PBT/PET yarn was established, and the change in mechanical properties was investigated theoretically. The results show that the strength of PBT/PET yarn decreases by 10.77%, and the elongation increase by 34.81% after dry-hear treatment at 160°C for 25 min. The mechanical properties of the yarn are affected by the temperature and time of heat treatment. XRD analysis shows that the crystallinity of PBT/PET yarn decreases with the increase of heat treatment temperature and time, which may be the reason for the change in mechanical properties of PBT/PET yarn. In addition, the established model can fairly well explain the viscoelasticity of PBT/PET yarn. [ABSTRACT FROM AUTHOR]

Carbon fiber reinforced polyetheretherketone polymer (CF/PEEK) thermoplastic composites have a marked plastic yield stage compared to thermoset composites with epoxy matrix. During the interference fit riveting process, extrusion between rivet and composites laminate creates plastic deformation on the hole wall, which will enhance the bearing capacity of composites hole. Therefore, it is expected that the interference fit will play a greater advantage in enhancing the bearing strength of CF/PEEK riveted joint. Numerical and experimental study are applied to investigate the effect of interference fit on bearing strength of CF/PEEK riveted joint. Results show that the plastic deformation of CF/PEEK composites hole wall is positively correlated with the bearing strength of CF/PEEK riveted joint. When the interference fit size exceeds 2.6%, the bearing capacity of CF/PEEK riveted joint reduces because of the increase of fiber damage. It is concluded that the plastic deformation of riveted hole wall can enhance the bearing capacity of CF/PEEK riveted joint, while fiber damage reduces the bearing capacity of CF/PEEK riveted joint. As the increase of interference‐fit size, bearing strength of CF/PEEK riveted joint raises first then decreases, the appropriate interference‐fit size is in the range of 2.0% ~ 2.6%, which is larger than that of thermoset composites. [ABSTRACT FROM AUTHOR]

This paper describes a visual sensor array for pattern recognition analysis of proteins based on two different optical signal changes: colorimetric and fluorometric, by using two types of novel blue-emitting collagen protected gold nanoclusters and macerozyme R-10 protected gold nanoclusters with lower synthetic demands. Eight proteins have been well-discriminated by this visual sensor array, and protein mixtures after one-dimensional polyacrylamide gel electrophoresis also could be well-discriminated. The possible mechanism of this sensor array was illustrated and validated by fluorescence spectra, X-ray photoelectron spectroscopy (XPS), fluorescence lifetime, isothermal titration calorimetry (ITC), and matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS) experiments. It was attributed to that the adsorption of proteins onto the surface of gold nanoclusters (Au NCs), forming the protein-Au NCs complex. Furthermore, serums from normal and hepatoma patients were also effectively discriminated by this visual sensor array, showing feasible potential for diagnostic applications.