In order to deal with the more and more serious problem of electromagnetic radiation pollution, cement-based composites were prepared by introducing glass fiber into cement as through wave reagent and carbon black as absorbing reagent . Arched testing method were used to test the reflection losses in the frequency range of 2~18 GHz. The results showed that the absorption properties were improved in high frequency compared with the pure cement. The filling ratio of carbon black and glass fiber as well as the thickness of samples had influence on the absorption properties. The lowest reflection loss of-11.2 dB was obtained at 18 GHz of 9wt.% glass fiber and 5wt.% carbon black filled cement with thickness of 10mm. The new material can be used for building indoor electromagnetic radiation protection.

Based on the viscoelastic and creep deformation properties, a new deposition mechanism model for slender wood fiber particles in wast heat utilization is proposed in this paper. And the equivalent sphere method is used to describe the particle feature size in the model. With the proposed deposition model of flexible slender particles, the critical criteria are obtained. The influence of particle size, aspect ratio and damping factor on particle deposition has been investigated. The results indicate that particle deposition increases with the particle size decrease, aspect ratio and damping factor increase. According to the present deposition model, a coupling simulation with FLUENT and EDEM method was carried out for the flow field of fiber drying tail gas in heat piping exchanger, which indicated that particle deposition mainly occurred at the central windward area of fin due to the direction changer and the magnitude decrease of collision velocity between fiber particles and wall. Experiment of heat recovery of drying tail gas revealed that using the H fin tubes instead of rectangular fin tubes can greatly relieve the deposition of wood fiber particles, which provided a useful way to save energy in wood industries.