In this article,from the most basic physics principle,the function of the piezoelectric transformer performance Vs three basic factors(mechanical quality factor,electromechanical coupling factor as well as electric quality factor) are established.

Strata quality factor (Q) and attenuation factor ( β ) especially these of near surface, are studied.

Simulation results show that better performance with smaller quality factor(Q) and boarder source moving range,and all these conclusions are obtained from viewpoints of the field uniformity and the probability density function(PDF).

Owing to the demand of oil and gas exploration and engineering prospecting,the research on acoustic attenuation of rocks is very active and quality factor Q is an important research field.

Calculation of quality factor of LVL in Tarim basin;

Inversion of phase velocity and quality factor from direct waves in vertical seismic profile data;

Computation of resonant frequencies and quality factors of dielectric cavities with finite-element method

The thermal fracture figure of merit,optical distortion figure of merit,and the thermal shock figure of merit are introduced,and applied to evaluate magnesium fluoride,spinel,sapphire,AlON,ZnS,ZnSe and diamond.

We introduce the recent progress of the thermoelectric materials, point out the wide appliance foreground in refrigeration and power source, analyze systematically the factors of which influence the figure of merit, put forward some possible ways to improve the figure of merit.