Based on the scalar diffractive theory, the authors analyze the relationships between diffractive efficiency of an integrated diffractive element (IDOE) combined with BSG&CSG and its structure parameters, distorted wavefront of low-frequency of main beam,respectively.

It is shown that low frequency driving octupole deformation makes a particle chaotic motion easier, the power frequency spectra more complicated and the magnitude of energy changing irregularly.

Study on Relationship Between Precursor Phenomena of Well Water Level and Seismic Source Nucleation;

Recording number of precursors from fourteen observation wells in Shanxi, Hebei, Beijing and Jiangsu region is analyzed and percentage of recording number of precursors to total number of earthquakes during the statistic years is presented.

5 days before the large earthquake,the long period precursor lasted 47 hours,the wave train presented regularly sine wave form,and the apperent period was about 8.

Three new scientific research finding and progress on decadal-scale correlation between crustal deformation and length of day, silent earthquake and precursory wave have been briefly introduced in this paper, and their implications to prem onitory anomaly and earthquake prediction are also analyzed.

Measurements of dynamic yield strength of aluminum alloy and mechanism analysis of elastic precursor during reloading;