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Epoxy resin (EP) was added to modify the compression set of the plasticized poly (vinyl chloride) (PVC). The effects of EP content and post-heat treatment on the mechanical properties were investigated. Experimental results showed that after post-heat treatment, the compression set decreased markedly and that the minimum was 46.48 % when the content of EP was 9 phr. The dispersion and distribution of epoxy resin in the matrix was observed with scanning electron microscopy (SEM), which showed that the post-heat treatment increased the cure density of EP obviously. Interaction occurred between the EP and PVC, which was characterized by Fourier transform infrared spectroscopy (FTIR) and X-Ray energy spectra. According to the results of differential scanning calorimetry (DSC), more ordering and close piled arrangement structure was formed in the matrix after post-heat treatment, which reduced the compression set further.

Wireless optical communication (WOC) technology delivers a cost-effective, secure, reliable, and efficient solution to the needs of customers who require fast performance network connections between multiple locations. One of the biggest challenges facing WOC deployment is proper understanding of optical signal propagation in different atmospheric conditions. Propagation of optical signals through these atmospheric turbulence channels causes attenuation and scattering of the transmitted beam. Atmospheric effects of absorption by rain, haze, scattering by particles (such as fog, and solar background radiation (SBR)) on Wireless Optical Communications for terrestrial communication were studied.

High-speed warhead fragments velocity measurement is one of the key technologies in investigating damage efficiency of warhead. We have designed and constructed a system to accurately determine the velocity of warhead fragments by measuring the time of flight between two parallel laser screens is presented. Each screen is formed by a laser source, a large photodetector and a retro-reflector. Optical output of the laser source is a collimated beam. The beam passes through cylindrical lens and the slit of photodetector reach to retro-reflector .The energy, reflected by retro-reflector; focus on the active area of photodetector. The system utilizes reflected ray by scotchlite retro-reflector as the start and end signal. And utilizes wideband circuit and data acquiring system to condition and sample signals. Experimental results show the system can measurement velocity are within the range from 20m/s to 2000m/s on target area of 1m2 and can perform satisfactorily with a wide range from 2000 lx to100,000lx. The measurement system also can be used to test velocity of projectile.

The issues of security and obstruction of line of sight are concerns of wireless optical communications (WOC). In this paper, an analysis of light beams carrying orbital angular momentum (OAM) used for WOC is undertaken. The basic description and conception of OAM of light are given. Encoding information both as the OAM states of a single light beam and as the spatial structure of the mixed light beams with OAM is discussed and compared. Using OAM to encode the data offers an inherent security enhancement. Mixed vortex fields with OAM possess a self-reconstruction property that is able to regenerate and to reconstruct their initial spatial distributions of the complex amplitude in the condition of obstruction of line of sight.