According to modeling of prototype,it was deduced that as long as the footings used in centrifugal and gravitational tests were different,the bearing capacity obtained in centrifugal tests was always larger than that obtained in gravitational tests,namely particle size effects always existed in centrifugal tests.

The results shows that the effective size and uniform coefficient for SP-1,SP-2 and SP-C are respectively 161.

In accordance with the effective size of nature soil conforming wostly with normal distribution, the physical signification and existing problem on the grading index of the soil grain are discussed.

At present,the main method of testing air filters is fraction efficiency testing method with particle counter.

By analyzing influence of shape coefficient and exposure degree,the formulas for calculating equivalent grain and the incipient motion condition of non-uniform sediment are established by the relative exposure degree and shape coefficient.

The formula for calculating the incipient motion condition of non-uniform sediment has been established by considering the equivalent grain and the relative exposure degree.

Based upon permeability test the influences of the porosity, average pore size, effective grain size, mean particle diameter and coarse grain on its permeability are studied.

The summarization of GPS technologies in mitigating multipath effects;

Explicit expressions are obtained in this article for the causation of the multipath effect in the SW communication.

To solve the multipath effect, the NSS based on Geometrical Theory of Diffraction (GTD) for approach landing systems is presented, including the methods that have been applied, and the simulation results for hangars problem.