Silver dendrite metasurface SERS substrates prepared by photoreduction method for perfluorooctanoic acid detection.

Perfluorooctanoic acid (PFOA), a novel organic pollutant, has been shown to be toxic, persistent, bioaccumulative, long-range transportable, and globally prevalent. This article is based on surface enhanced Raman scattering (SERS) spectroscopy analysis technology. The monolayer of SiO was prepared by chemical reduction etching self-assembly method and silver dendrites were grown on it, thus forming the SERS substrate with silver dendrite Metasurface structure with Raman detection enhancement factor up to 2.

Subwavelength topological structures resulting from surface two-plasmon resonance by femtosecond laser exposure solid surface.

We present that surface two-plasmon resonance (STPR) in electron plasma sheet produced by a femtosecond laser irradiating a solid surface is the self-formation mechanism of periodic subwavelength ripple structures. Peaks of overdense electrons, formed by resonant two-plasmon wave mode, pull bound ions out of the metal surface. Thus, the wave pattern of STPR is "carved" on the surface by Coulomb ablation (removal) due to periodic distributed strong electrostatic field produced by charge separation.

[Effect of flavonoids from Sophora flavescens in aging mice induced by D-galactos].

To investigate the effect of flavonoids from Sophora flavescens in aging mice induced by D-galactose and its mechanism. Totally 60 mice were randomly divided into six groups: the control group, the model group, the piracetam group (positive control group) and flavonoids from S. flavescens low, medium and high doses groups.

A modified rate equation for the propagation of a femtosecond laser pulse in field-ionizing medium.

A recombination rate of electron-ion in the strong-field atomic process is phenomenologically introduced into the ionization rate equation, and therefrom an ionization and recombination rates equation (IRRE) is obtained. By using the extended IRRE, the propagation equation of an intense femtosecond laser pulse in the gaseous medium is re-derived. Some new physical behaviors and characteristics caused by the introduced recombination rate are discussed in detail.