Sphere-shape Eu（DBM）3Phen@Si02 nanoparticles were fabricated by employing a modified alkaline catalyzed hydrolysis and precipitation method. The silica coated on the particles surface was obtained by means of hydrol...Sphere-shape Eu（DBM）3Phen@Si02 nanoparticles were fabricated by employing a modified alkaline catalyzed hydrolysis and precipitation method. The silica coated on the particles surface was obtained by means of hydrolysis and condensation of tetraethyl orthosilicate （TEOS）. In this study, the particles morphology was analyzed by scanning electron microscopy （SEM） and the surface composition of samples was characterized by X-ray diffraction （XRD） and Fourier transform infrared spectroscopy （FT-IR）. It is confirmed that the Si02 shell has been coated on the rare earth complexes successfully. Moreover, the near-infrared photoluminescence emission analysis on the nanoparticles showed that the SiO2 shell would increase the luminescence intensity of Eu（DBM）3Phen. This is primarily due to the reason that SiO2 shell with chemical inertness can effectively reduce the ion Eu3~ non-radiation transition probabilities, as well as the probability of rare earth luminescence quenching caused by the external medium.展开更多
Sub-micron sized phenolic epoxy resin waterborne particles were prepared by phase inversion emulsification. Micro-phase separation occurred during the curing process at high temperature. The as-prepared samples posses...Sub-micron sized phenolic epoxy resin waterborne particles were prepared by phase inversion emulsification. Micro-phase separation occurred during the curing process at high temperature. The as-prepared samples possessed one glass transition temperature （Tg） and two exothermal processes during DSC heating scannings. After being thermally treated above the exothermal peak temperature, they possessed two glass transition temperatures with the disappearance of exothermal peaks, whilst a core/shell structure was formed. This was likely related with the outward diffusion of reactive oligomers to the outer layer of particles.展开更多
To analyze the micro-track structure of heavy ions in a polymer material, parameters including bulk etch rate, track etch rate, etch rate ratio, and track core size were measured. The pieces of CR-39 were exposed to 1...To analyze the micro-track structure of heavy ions in a polymer material, parameters including bulk etch rate, track etch rate, etch rate ratio, and track core size were measured. The pieces of CR-39 were exposed to 100 MeV Si ions with normal incidence and were etched in 6.25N NaOH solution at 70 ℃. Bulk etch rate was read out by a profilemeter after several hours of etching. The other parameters were obtained by using an atomic force microscope （AFM） after a short time of etching. We have measured the second etch pits and minute etch pits to obtain the track growth curve and three dimension track structures to track the core size and etch rate measurements. The local dose of the track core was calculated by the δ-ray theory. In our study, we figure out that the bulk etch rate Vb=（1.58±0.022） μm/h, the track etch rate Vt=（2.90±0.529） μ/h, the etch rate ratio V=1.84±0.031, and the track core radii r≈4.65 nm. In the meantime, we find that the micro-track development violates the traditional track-growth model. For this reason, a scenario is carried out to provide an explanation.展开更多
基金financial support from the National Natural Science Foundation of China (No. 60972134, No. 51205137)the Fundamental Research Funds for the Central Universities with grant no. 2012ZM0067
文摘Sphere-shape Eu（DBM）3Phen@Si02 nanoparticles were fabricated by employing a modified alkaline catalyzed hydrolysis and precipitation method. The silica coated on the particles surface was obtained by means of hydrolysis and condensation of tetraethyl orthosilicate （TEOS）. In this study, the particles morphology was analyzed by scanning electron microscopy （SEM） and the surface composition of samples was characterized by X-ray diffraction （XRD） and Fourier transform infrared spectroscopy （FT-IR）. It is confirmed that the Si02 shell has been coated on the rare earth complexes successfully. Moreover, the near-infrared photoluminescence emission analysis on the nanoparticles showed that the SiO2 shell would increase the luminescence intensity of Eu（DBM）3Phen. This is primarily due to the reason that SiO2 shell with chemical inertness can effectively reduce the ion Eu3~ non-radiation transition probabilities, as well as the probability of rare earth luminescence quenching caused by the external medium.
基金This work was financially supported by the National Natural Science Foundation of China(No.20104008).
文摘Sub-micron sized phenolic epoxy resin waterborne particles were prepared by phase inversion emulsification. Micro-phase separation occurred during the curing process at high temperature. The as-prepared samples possessed one glass transition temperature （Tg） and two exothermal processes during DSC heating scannings. After being thermally treated above the exothermal peak temperature, they possessed two glass transition temperatures with the disappearance of exothermal peaks, whilst a core/shell structure was formed. This was likely related with the outward diffusion of reactive oligomers to the outer layer of particles.
文摘To analyze the micro-track structure of heavy ions in a polymer material, parameters including bulk etch rate, track etch rate, etch rate ratio, and track core size were measured. The pieces of CR-39 were exposed to 100 MeV Si ions with normal incidence and were etched in 6.25N NaOH solution at 70 ℃. Bulk etch rate was read out by a profilemeter after several hours of etching. The other parameters were obtained by using an atomic force microscope （AFM） after a short time of etching. We have measured the second etch pits and minute etch pits to obtain the track growth curve and three dimension track structures to track the core size and etch rate measurements. The local dose of the track core was calculated by the δ-ray theory. In our study, we figure out that the bulk etch rate Vb=（1.58±0.022） μm/h, the track etch rate Vt=（2.90±0.529） μ/h, the etch rate ratio V=1.84±0.031, and the track core radii r≈4.65 nm. In the meantime, we find that the micro-track development violates the traditional track-growth model. For this reason, a scenario is carried out to provide an explanation.
