Sulfated zirconia/silica(SZ/SiO2) complex nanofibers were prepared by combining electronspinning technique and sol-gel method.First,a silica sol was electrospun at a voltage of 12 kV,then the as-electrospun silica nan...Sulfated zirconia/silica(SZ/SiO2) complex nanofibers were prepared by combining electronspinning technique and sol-gel method.First,a silica sol was electrospun at a voltage of 12 kV,then the as-electrospun silica nanofibers were immersed into a sulfated zirconia sol afterwards with a thermal treatment to obtain the SZ/SiO2 complex nanofibers.These fibers were examined by SEM,TEM,FTIR, XRD and SPS.The results indicate that the SZ nanopaticles with the average diameter of about 8 nm were disspered on the surface of silica fibers which had an average diameter of about 170 nm.The complex nanofibers had an amorphous structure.The observation of the surface-related transitions at the SPS spectrum indicates the presence of positive charges on the surface of the complex fibers.展开更多
REE geochemistry has been studied with respect to sea-floor sediments in the continental shelf of East China Sea. The average content of RE2O3 is derived as 175 ppm based on 68 samples of the continental Y and La-Lu i...REE geochemistry has been studied with respect to sea-floor sediments in the continental shelf of East China Sea. The average content of RE2O3 is derived as 175 ppm based on 68 samples of the continental Y and La-Lu in the abovementioned shelf sediments, The absolute concentrations of sediments are shown in Table 3. The REE distribution patterns of the sediments demonstrate a distinct depletion in Eu and a negative slope. It is considered that the fragments of Mesozoic intermediate-acid igneous rocks widely distributed in southeastern China are the main souree of REE in sea-floor sediments of the continental shelf.展开更多
Poly（vinyl pyrrolidone）（PVP）/Fe 3O 4 composite nanofibers were successfully prepared by using electrospinning technique.The composite nanofibers were characterized by means of TEM（transmission electron microscopy...Poly（vinyl pyrrolidone）（PVP）/Fe 3O 4 composite nanofibers were successfully prepared by using electrospinning technique.The composite nanofibers were characterized by means of TEM（transmission electron microscopy）,XRD（X-ray diffraction）and TGA（thermogravimetric analysis）.Transmission electron microscope images of the PVP/Fe3O4 nanofibers show that the Fe3O4 nanoparticles with a diameter about 10.5 nm were dispersed in PVP fiber matrices.The XRD results show that the particles in PVP fibers were indeed Fe3O4 nanoparticles.And the TGA of PVP/Fe3O4 nanofibers show that the content of Fe3O4 nanoparticles in the composite was about 36.8%（mass fraction）.The PVP/Fe3O4 nanofibers were found to be superparamagnetic.The hysteresis loop at room temperature showed a high saturated magnetization（M s=15.1 emu/g）and a low coercive force（μ c=0）.展开更多
文摘Sulfated zirconia/silica(SZ/SiO2) complex nanofibers were prepared by combining electronspinning technique and sol-gel method.First,a silica sol was electrospun at a voltage of 12 kV,then the as-electrospun silica nanofibers were immersed into a sulfated zirconia sol afterwards with a thermal treatment to obtain the SZ/SiO2 complex nanofibers.These fibers were examined by SEM,TEM,FTIR, XRD and SPS.The results indicate that the SZ nanopaticles with the average diameter of about 8 nm were disspered on the surface of silica fibers which had an average diameter of about 170 nm.The complex nanofibers had an amorphous structure.The observation of the surface-related transitions at the SPS spectrum indicates the presence of positive charges on the surface of the complex fibers.
文摘REE geochemistry has been studied with respect to sea-floor sediments in the continental shelf of East China Sea. The average content of RE2O3 is derived as 175 ppm based on 68 samples of the continental Y and La-Lu in the abovementioned shelf sediments, The absolute concentrations of sediments are shown in Table 3. The REE distribution patterns of the sediments demonstrate a distinct depletion in Eu and a negative slope. It is considered that the fragments of Mesozoic intermediate-acid igneous rocks widely distributed in southeastern China are the main souree of REE in sea-floor sediments of the continental shelf.
文摘Poly（vinyl pyrrolidone）（PVP）/Fe 3O 4 composite nanofibers were successfully prepared by using electrospinning technique.The composite nanofibers were characterized by means of TEM（transmission electron microscopy）,XRD（X-ray diffraction）and TGA（thermogravimetric analysis）.Transmission electron microscope images of the PVP/Fe3O4 nanofibers show that the Fe3O4 nanoparticles with a diameter about 10.5 nm were dispersed in PVP fiber matrices.The XRD results show that the particles in PVP fibers were indeed Fe3O4 nanoparticles.And the TGA of PVP/Fe3O4 nanofibers show that the content of Fe3O4 nanoparticles in the composite was about 36.8%（mass fraction）.The PVP/Fe3O4 nanofibers were found to be superparamagnetic.The hysteresis loop at room temperature showed a high saturated magnetization（M s=15.1 emu/g）and a low coercive force（μ c=0）.
