Papers by Keyword: Silica Fiber

Abstract: The rectangular-structured resin with one of its triangular long-period fiber grating surface is designed and printed out by using a high resolution 3D printer, so called long-period fiber grating (LPFG) resin. This LPFG resin is directly pressed on the bare single-mode fiber by a digital force meter to filter out partial band of light inside the fiber. The grating period is expanded by tilting the resin from the initial fiber axis. The optical filter is observed as resonant wavelengths from the broadband wavelength. The results show that the resonant wavelength shift is a linear function of the grating period with the coefficient of determination over 0.99. The proposed scheme has a great potential to be employed as a sensor such as a selective optical filter and a buried intrusion sensor.

Abstract: Silica fibers were prepared from the agricultural waste-rice straw via a slow calcination process. A possible formation mechanism of the obtained silica fiber was explained. The phytoliths/vascular composite fibers of rice straw work as the structural directing templates for the formation of silica fibers under the slow calcination process. Owing to the potassium silicate active site, the separable silica fiber showed great capability in removal of Cu²⁺, Ni²⁺, Cd²⁺ and Pb²⁺ from aqueous solution with efficiency higher than 99%. Additionally, over 90% of equilibrium adsorption capacity can be reached within 10 minutes, showing the easily accessible paths and active sites for ion transportation and adsorption in the as-prepared fiber. These results of this work are beneficial for scientists pursuing new synthetic route for valuable and widely applicable silica fiber materials from the agricultural waste, also helping to solve disposal of the agricultural waste and pollution problems.

Abstract: The properties of TiO₂-doped fiber are considered as optoelectronic material in our work. The advantages of such fiber have been studied with the aim of its application to active medium in Raman fiber lasers. The comparison of spontaneous Raman spectra and corresponding gain profiles in TiO₂-doped and GeO₂-doped fiber is presented. Raman gain profiles were obtained over a broad spectral range of Stokes shifted frequencies up to 1400 cm^-1(42 THz). The spectral decomposition using multimode Gaussian components has been performed for both Raman gain profiles. High accuracy analytic form of Raman gain profile of TiO₂-doped fiber is obtained using 12 components. The pump power of Raman gain threshold is introduced as the function of wavelength within the telecommunication windows for both fiber types. Our spectroscopic analysis allows presenting the numerical results on lasing bandwidth and Raman gain threshold inTiO₂-doped single-mode fiber. It has been shown that the lasing bandwidth in TiO₂-doped fiber may be almost twice wider than the lasing bandwidth in standard GeO₂-doped fiber.

Abstract: Uniform immobilization of BiFeO₃ on silica fiber was successfully obtained by a combined impregnation method with carbon nanofibers (CNFs) template route. The physicochemical properties of the obtained material were characterized by means of X-ray diffraction, field emission scanning electron microscopy, and ultraviolet-visible diffuse reflectance spectroscopy. It turned out that BiFeO₃ immobilized on silica fiber can exhibit visible light photocatalytic degradation of rhodamine B (RhB) to some extents. It is expected that such kind of material would possess many potential applications in photocatalysis.

Abstract: Uniform growth of WO3 with macroscopic structures was successfully achieved by using carbon nanofibers (CNFs) as template. Field emission scanning electron microscopy (FE-SEM), coupled with X-ray diffraction (XRD) analysis confirmed the template effect and the existence of WO3 immobilized on the macroscopic silica fiber.

Abstract: Three-dimensional silica fiber reinforced silicon nitride composites were prepared by polymer infiltration and pyrolysis method using perhydropolysilazane (PHPS) and polyhydridomethylsilazane (PHMS), respectively. The microstructures of the composites were characterized by transmission electron microscopy. Strong fiber/matrix interfacial adhesion was observed for the PHPS-derived composites prepared at 1073K, and the PHMS-derived composites prepared at 873K without fiber precoating. While for the PHMS-derived composites prepared at 873K with fiber precoating, the coating changed the fiber/matrix interfacial bonding conditions, leading to high mechanical properties.

Abstract: Sizing removal of silica fibers was carried out by air heat-treatment, and the mechanical strength, surface condition, microstructures were studied by tensile breaking force measurement, X-ray photoelectron spectroscopy, field emission scanning electron microscope and high-resolution transmission electron microscope. Heat-treatment at 600°C in air was suitable for sizing removal of silica fibers, with the residual strength ratio of 26.6%. The effects of sizing removal by air heat-treatment on the silica fibers are: (a) the sizing acts as an protective layer for the silica fibers to cover the surface defects and decrease the sensitivity under external forces, and the tensile strength drops a lot after the sizing removal; (b) the decomposition and combustion of the epoxy sizing also lead to the embrittlement of the silica fibers.

Abstract: Silica fibers are widely used in superhigh velocity radome and antenna windows. The methods of eliminating the agents on the surface silica fibers were sdudied in this paper. SEM was engaged in studying the effects of silica fibers disposed by different methods,and the tensile strength of disposed silica fbers was compared with the originals. The results show that the heat treatment in the high temperature was a useful means to eliminate the agent on the surface of silica fiber, but there was great thermal damage for silica fibers,and the tensile strenth decreased significantly. The combination of volvent treatment and heat tratment could eliminate the agent on tht surface of silica fibers completely,and the tensile strength retained more, which was a good means to eliminate the agents on the surface of silica fiber.

Abstract: The high-temperature resistance compression material of lightweight porous ceramics and fiber joining is becoming a kind of promising seal parts in high-temperature industries and aerospace field. A combination of the lightweight mullite matrix porous ceramics and the elastic 3-D silica woven fibre, a novel joining material was studied. The low cost fly ash cenosphere as raw materials, mullite porous ceramics with density 0.92 g/cm³, and the thermal conductivity 0.13 w/m.K, were prepared. Using microwave selective heating properties, designing the interlayer composition, the bonding materials were attained by microwave sintering. The flexural strength of joint materials was about 23 MPa, which was higher than porous ceramics matrix.

Abstract: The growth of carbon nanofibers (CNFs) with ordered macroscopic structures could be achieved by CVD technique. Silica fiber, alumina fiber, and AAO membrane were selected as the typical ordered macroscopic substrates for CNFs growth. It turned out that silica fiber could act as the promising and effective substrate for CNFs growth on its surface. While alumina fiber and AAO membrane could also be expected to act as the potential substrates for CNFs growth on their surface.