Search

A new polyvinyl alcohol foam gel/MOF-808 detergent was used to study the uranium removal process on the cement surface, and the mechanism was deeply analyzed. Through the mutual verification of XPS, infrared spectrum, XRD and SEM, it is confirmed for the first time that MOF-808 mainly relies on its own Zr-OH and carboxyl groups to remove uranyl ions in foam gel, rather than the carboxyl groups on the ligand. Foam gel combined with MOF-808 can improve the decontamination factor of cement surface by 37.3%, and the maximum removal rate of uranium pollution on cement surface can reach 68.1%. [ABSTRACT FROM AUTHOR]

In this work, a foam gel material based on polyvinyl alcohol were successfully prepared to remove uranium contamination on the surface of stainless steel. The material was tested through infrared spectroscopy and thermogravimetric analysis. The decontamination process of the foam gel on stainless steel surface was analyzed by SEM/EDS and XPS. The results show that the foam gel has good stripping properties, and its decontamination factor for removal of radioactive uranium on stainless steel surfaces could reach 90.9, which seems better than the methods of water washing and wiping. [ABSTRACT FROM AUTHOR]

Extended X-ray absorption fine structure (EXAFS) spectroscopic investigation and sequential extraction were utilized to characterize the adsorption form of Cs in soil. The experimental results show that Cs+ mainly adsorbs on the surface of soil samples S1 and S2, which is a type of weak adsorption. Results of sequential extraction experiments can be directly explained with EXAFS spectra of the samples. The chemical index of weathering (CIW) of the soil has a decisive impact on the adsorption form of Cs+. The research results can provide strong support for the study of the adsorption and blocking behavior of cesium ions by the I/S mixed layer structure in soil. [ABSTRACT FROM AUTHOR]

New solution techniques to improve the accuracy of quantitatively determining the atmospheric extinction coefficient and the backscattering-to-extinction ratio from lidar signals are developed. The integration method is proposed to analytically retrive the extinction coefficient at ground level, which has the advantage of eliminating the effect of backscattering fluctuations on the inversion results. The ratio method, on the other hand, deals with the inversion of the vertical distribution of the extinction coefficient. The main idea of this method is to begin with a calculation of the transmittance by eliminating the backscattering through ratioing lidar signals at two elevations, and subsequently derive the extinction coefficient from the transmittance, thus avert from ambiguous results caused by inappropriate assumptions on the backscattering-to-extinction ratio. Observational investigations have demonstrated that the integration method is superior to the slope method in terms of accuracy and stability, and the ratio method is reasonable and feasible as well. [ABSTRACT FROM AUTHOR]

Although it has long been recognized that the effects of photon multiple scattering generally need to be accounted for in the analysis of lidar cloud returns, this is a difficult problem and current approaches are still rudimentary. The multiple scattering process is controlled by the size of the lidar beamwidth and the distance to the cloud, which jointly determine the lidar footprint, but cloud microphysical content (i.e., particle size, concentration, and shape) exerts a strong influence on the range distribution and depolarization of the returned energy. Since clouds are inherently inhomogeneous with height, it is our premise that vertically homogeneous cloud simulations based on idealized particle size distributions lead to misleading results. We offer a more realistic approach based on the contents of growing water droplet clouds predicted by a sophisticated adiabatic cloud model, which are offered for use as new standard vertically-inhomogeneous cloud models. Lidar returned signal and depolarization profiles derived from our analytical double-scattering method are given for inter-comparison purposes. [ABSTRACT FROM AUTHOR]