Papers by Author: Kai Chen

Abstract: On the condition that there are no available cooperative peers, this paper proposes self-cooperative network coding. Self-cooperative network coding is that the sender makes use of time diversity technologies to offer cooperative information by itself. One advantage of self-cooperative network coding is that with the increase of the number of packets, successful transmission rate become high. Consequently, self-cooperative network coding provides a solution for reliable transmission of the large file in deep space under condition of low signal noise ratio of received signal and huge transmission delay.

Abstract: Through the metallographic and electron microscopic analysis on the tensile specimens of low-alloy-high-strength-welding HG70C, we can see that the hot rolling process has an effect on mechanical properties of HG70C: the longer the heating time is, the stronger the yield strength and tensile strength will be. The thicker the finishing slabs are,the stronger the yield strength and tensile strength will be. But it has little effect on the elongation rate. The longer the heating time is, the more even these organizations will be. The decrease of rolling pressure will reduce the aggregation of the inclusion and the formation of banded structure which is conducive to improving the yield strength and tensile strength of HG70C. And martensite is a product of high temperature. There is certain relationship between the formation of banded structure and the formation of martensite.

Abstract: CaCu3Ti4O12 and CaCu3Ti3.9Zr0.1O12 ceramics were prepared by the traditional solid-state reaction method and the dielectric properties were investigated. Comparison of the results of the two samples examined indicated that the partial replacement of titanium by zirconium in the system CaCu3Ti4O12 may result in different changes of the dielectric constant and dielectric loss. For these experimental phenomena possible explanations and predictions also have been presented.

Abstract: A new approach to obtain Si nanostructures on insulating layer is proposed by laser irradiation on ultra-thin hydrogenated amorphous silicon (a-Si:H) films with subsequently thermal annealing. It was found that the surface nanostructuring was occurred when the laser fluence exceeded the threshold value as revealed by AFM images. The size and area density of formed Si nanostructures were depended on the laser fluence and film thickness while thermal annealing played an important role in the size and its distribution. The results showed that a high density (>1011cm-2) Si nanostructures with average lateral size of 10-20nm can be achieved by the present technology.