Sea-ice concentration is a key item in global climate change research. Recent progress in remotely sensed sea-ice concentration product has been stimulated by the use of a new sensor, advanced microwave scan- ning rad...Sea-ice concentration is a key item in global climate change research. Recent progress in remotely sensed sea-ice concentration product has been stimulated by the use of a new sensor, advanced microwave scan- ning radiometer for EOS （AMSR-E）, which offers a spatial resolution of 6 km×4 km at 89GHz, A new inver- sion algorithm named LASI （linear ASI） usingAMSR-E 89GHz data was proposed and applied in the antarc- tic sea areas. And then comparisons between the LASI ice concentration products and those retrieved by the other two standard algorithms, ASI （arctic radiation and turbulence interaction study sea-ice algorithm） and bootstrap, were made. Both the spatial and temporal variability patterns of ice concentration differ- ences, LASI minus ASI and LASI minus bootstrap, were investigated. Comparative data suggest a high result consistency, especially between LASI and ASI. On the other hand, in order to estimate the LASI ice concen- tration errors introduced by the tie-points uncertainties, a sensitivity analysis was carried out. Additionally an LASI algorithm error estimation based on the field measurements was also completed. The errors suggest that the moderate to high ice concentration areas （〉70%） are less affected （never exceeding 10%） than those in the low ice concentration. LASI and ASI consume 75 and 112 s respectively when processing the same AMSR-E time series thourghout the year 2010. To conclude, by using the LASI algorithm, not only the sea- ice concentration can be retrieved with at least an equal quality as that of the two extensively demonstrated operational algorithms, ASI and bootstrap, but also in a more efficient way than ASI.展开更多
A frontier topic in nanotechnology is the realization of multifunctional nanoparticles （NPs） via the appropriate combination of different elements of the periodic table. The coexistence of Fe and Ag in the same nano...A frontier topic in nanotechnology is the realization of multifunctional nanoparticles （NPs） via the appropriate combination of different elements of the periodic table. The coexistence of Fe and Ag in the same nanostructure, for instance, is interesting for nanophotonics, nanomedicine, and catalysis. However, alloying of Fe and Ag is inhibited for thermodynamic reasons. Here, we describe the synthesis of Fe-doped Ag NPs via laser ablation in liquid solution, bypassing thermodynamics constraints. These NPs have an innovative structure consisting of a scaffold of face-centered cubic metal Ag alternating with disordered Ag-Fe alloy domains, all arranged in a truffle-like morphology. The Fe-Ag NPs exhibit the plasmonic properties of Ag and the magnetic response of Fe-containing phases, and the surface of the Fe-Ag NPs can be functionalized in one step with thiolated molecules. Taking advantage of the multiple properties of Fe-Ag NPs, the magnetophoretic amplification of plasmonic properties is demonstrated with proof-of-concept surface-enhanced Raman scattering and photothermal heating experiments. The synthetic approach is of general applicability and virtually permits the preparation of a large variety of multi-element NPs in one step.展开更多
基金The Youth Science Fund Project of the National Science Foundation of China under contract No.41006016
文摘Sea-ice concentration is a key item in global climate change research. Recent progress in remotely sensed sea-ice concentration product has been stimulated by the use of a new sensor, advanced microwave scan- ning radiometer for EOS （AMSR-E）, which offers a spatial resolution of 6 km×4 km at 89GHz, A new inver- sion algorithm named LASI （linear ASI） usingAMSR-E 89GHz data was proposed and applied in the antarc- tic sea areas. And then comparisons between the LASI ice concentration products and those retrieved by the other two standard algorithms, ASI （arctic radiation and turbulence interaction study sea-ice algorithm） and bootstrap, were made. Both the spatial and temporal variability patterns of ice concentration differ- ences, LASI minus ASI and LASI minus bootstrap, were investigated. Comparative data suggest a high result consistency, especially between LASI and ASI. On the other hand, in order to estimate the LASI ice concen- tration errors introduced by the tie-points uncertainties, a sensitivity analysis was carried out. Additionally an LASI algorithm error estimation based on the field measurements was also completed. The errors suggest that the moderate to high ice concentration areas （〉70%） are less affected （never exceeding 10%） than those in the low ice concentration. LASI and ASI consume 75 and 112 s respectively when processing the same AMSR-E time series thourghout the year 2010. To conclude, by using the LASI algorithm, not only the sea- ice concentration can be retrieved with at least an equal quality as that of the two extensively demonstrated operational algorithms, ASI and bootstrap, but also in a more efficient way than ASI.
文摘A frontier topic in nanotechnology is the realization of multifunctional nanoparticles （NPs） via the appropriate combination of different elements of the periodic table. The coexistence of Fe and Ag in the same nanostructure, for instance, is interesting for nanophotonics, nanomedicine, and catalysis. However, alloying of Fe and Ag is inhibited for thermodynamic reasons. Here, we describe the synthesis of Fe-doped Ag NPs via laser ablation in liquid solution, bypassing thermodynamics constraints. These NPs have an innovative structure consisting of a scaffold of face-centered cubic metal Ag alternating with disordered Ag-Fe alloy domains, all arranged in a truffle-like morphology. The Fe-Ag NPs exhibit the plasmonic properties of Ag and the magnetic response of Fe-containing phases, and the surface of the Fe-Ag NPs can be functionalized in one step with thiolated molecules. Taking advantage of the multiple properties of Fe-Ag NPs, the magnetophoretic amplification of plasmonic properties is demonstrated with proof-of-concept surface-enhanced Raman scattering and photothermal heating experiments. The synthetic approach is of general applicability and virtually permits the preparation of a large variety of multi-element NPs in one step.
