White LED light source radar system for multi-wavelength remote sensing measurement of atmospheric aerosols.

A Mie scattering radar system with a white light-emitting diode (LED) light source is proposed for the multi-wavelength detection of atmospheric aerosols. By splitting the continuous spectrum, the multi-wavelength echo signals are extracted to achieve multi-wavelength real-time detection of atmospheric aerosols. The white LED spectrum characteristics are analyzed, and four detection wavelengths are set at 450, 525, 600, and 661 nm. The composition and detection principles of a white LED light source radar system are expounded, the design of each system part is described in detail, and the system parameters and data inversion algorithm are presented. We built a white LED light source radar system and conducted preliminary observation experiments. The results show that radar can achieve multi-wavelength real-time detection of atmospheric aerosols within a 300 m height, which can provide effective data for further study of aerosol particle distribution and lay a foundation for further studies of aerosol characteristics at special wavelengths.

Application of polymeric ferric sulfate combined with cross-frequency magnetic field in the printing and dyeing wastewater treatment.

Polymeric ferric sulfate (PFS) was pretreated with a self-made alternating frequency magnetic field for coagulation printing and dyeing (PD) wastewater treatment. The effects of PFS dosage, magnetization intensity, frequency, and time on the removal of chemical oxygen demand (COD), color and turbidity of PD wastewater were investigated. The results indicated that the magnetized PFS significantly improved the removal efficiency in wastewater treatment. When the initial COD, color and turbidity of printing and dyeing wastewater was 464 mg/L, 180 degrees, and 54.8 NTU respectively, the maximum removal rate of COD, color and turbidity was 87.9%, 80.1%, and 95.2% respectively, under the condition of cross frequency magnetic field magnetization PFS. Moreover, the PFS treatment combined with cross-frequency magnetic field could greatly reduce the pollution of iron ions released from iron-based coagulant during wastewater treatment. Characterization of magnetized PFS flocculant by fourier transform infrared spectroscopy, ultraviolet and visible spectrophotometry, and scanning electron microscopy suggested that magnetic crystal with larger size can be formed on the surface of PFS particles.