A speckle noise suppression method based on surface waves investigation and monitoring data

The internal energy distribution of waves can be described using ocean-wave spectra.In many ways,obtaining wave spectra on a global scale is critical.Surface waves investigation and monitoring onboard the Chinese-French oceanography satellite is the first space-borne instrument for detecting wave spectra specially,which was launched on October 29,2018.It can avoid the shortage of synthetic aperture radar detection results while still having some problems,especially with the effects of speckle noise.In this study,a method to suppress the speckle noise is proposed.First,the empirical formula for background speckle noise is established.Second,many spatio-temporal representative fluctuation spectra are classified and averaged.Third,rational transfer function filtering is used to obtain speckle noise close to the along-track direction.Finally,a signal-to-noise ratio threshold is used to suppress the abnormal speckle noise.This method solves the problems existing in previous denoising methods,such as excessive denoising in the along-track direction and the inability of some abnormal noises to be denoised in the two-dimensional directional wave spectra.

Non‑Leaching,Rapid Bactericidal and Biocompatible Polyester Fabrics Finished with Benzophenone Terminated N‑halamine

Pathogenic bacteria can proliferate rapidly on porous fabrics to form bacterial plaques/bioflms,resulting in potential sources of cross-transmissions of diseases and increasing cross-infection in public environments.Many works on antibacterial modifcation of cotton fabrics have been reported,while very few works were reported to endow poly(ethylene terephthalate)(PET)fabrics with non-leaching antibacterial function without compromising their innate physicochemical properties though PET is the most widely used fabric.Therefore,it is urgent to impart the PET fabrics with non-leaching antibacterial activity.Herein,a novel N-halamine compound,1-chloro-3-benzophenone-5,5-dimethylhydantoin(Cl-BPDMH),was developed to be covalently bonded onto PET fabrics,rendering non-leaching antibacterial activity while negligible cytotoxicity based on contact-killing principle.Bacterial was easily adhered to Cl-BPDMH fnished PET fabrics,and then it was inactivated quickly within 10 s.Furthermore,the breaking strength,breaking elongation,tearing strength,water vapor permeability,air permeability and whiteness of Cl-BPDMH fnished PET fabrics were improved obviously compared to raw PET fabrics.Hence,this work developed a facile approach to fabricate multifunctional synthetic textiles to render outstanding and rapid bactericidal activity without compromising their physicochemical properties and biocompatibility.