RESUMO
We numerically study a hybrid mode-locked holmium-doped fiber laser based on the coupled nonlinear Schrödinger equations, by introducing nonlinear polarization rotation and saturable absorber in a same cavity. Maps of mode-locking states related to the intracavity wave-plates are created to evaluate the stability of mode-locking. Nonlinear polarization rotation imposes negative effect of linear absorption and even reverse saturable absorption to the pulses in the hybrid cavity. Saturable absorber compensates the negative effect from nonlinear polarization rotation, then consequently contributes to the stability of single-pulse mode-locking states. The extension of pulse time duration indicates the dynamic synergy between nonlinear polarization rotation and saturable absorber rather than the static combination mechanism of them.
RESUMO
Here we report a simple, facile and low-cost approach to the cotton textile with significant properties. After treatment, the cotton textiles exhibit not only an excellent superhydrophobicity with the water contact angle (WCA) of 151.5(o), but also an efficient shielding property against UV with the transmittance under 2.0%. More importantly, this cotton displays an outstanding potency in oil reclaim, which can recycle oil from the waste water with oil stain efficiently. Apparently, our results suggest an innovative material that should find practical and diversified applications, particularly in the field of oil spill cleanup.
Assuntos
Fibra de Algodão , Têxteis , Raios Ultravioleta , Interações Hidrofóbicas e HidrofílicasRESUMO
A composite filter paper with super-hydrophobicity was obtained by adhering micro/nano structure of amorphous titanium dioxide on the filter paper surface with modifying low surface energy material. By virtue of the coupling agent, which plays an important part in bonding amorphous titanium dioxide and epoxy resin, the structure of super-hydrophobic thin film on the filter paper surface is extremely stable. The microstructure of super-hydrophobic filter paper was characterized by scanning electron microscopy (SEM), the images showed that the as-prepared filter paper was covered with uniform amorphous titanium dioxide particles, generating a roughness structure on the filter paper surface. The super-hydrophobic performance of the filter paper was characterized by water contact angle measurements. The observations showed that the wettability of filter paper samples transformed from super-hydrophilicity to super-hydrophobicity with the water contact angle of 153 ± 1°. Some experiments were also designed to test the effect of water-oil separation and UV-resistant by the super-hydrophobic filter paper. The prepared super-hydrophobic filter paper worked efficiently and simply in water-oil separation as well as enduringly in anti-UV property after the experiments. This method offers an opportunity to the practical applications of the super-hydrophobic filter paper.
RESUMO
Cotton with superhydrophobic and superoleophilic properties had been successfully fabricated for application in the field of oil/water separation by the combination of SiO2 nanoparticles on cotton fiber surface and subsequent octadecyltrichlorosilane modification. The as-prepared cotton could be used to selectively absorb various common oils and organic solvents up to above 50 times of its own weight while repelling water completely. The absorbed oils were easily collected by a simple vacuum filtration, and the recovered cotton could be reused for several cycles while still keeping high absorption capacity. Moreover, the as-prepared cotton was simply spun into cloth, which not only could be tailored to the water-repellent clothing but also could be used in the oil/water separation filter system. The results presented in this work might provide a simple, low-cost and environment friendly approach for application in the field of water/oil separation.