Nanoindentation has been widely used to evaluate and test material properties,we utilize the unloading curves of an indentation test to extract the hardness and reduced modulus of the material.

This paper presented a method that combination modulus of pile and soil complex under effects of pile and soil interaction,that effects of pile nearby and pile groups was considered.

This paper discusses the probloms of collision, extends the result in ref - which show the formula of the mechanical energy loss to the situation of oblique collision, simplifies the result by using the reduced mass, analyses the result with Knig s theorem and studies the result of the perfectly inelastic collision of many-body system.

The reduced kinetic energy is discussed using the reduced mass of the constrained two bodies.

In the teaching of central field, we should pay attention to turning the relative motion of two - body into one dimentuonal radial motion by introducing two physical concepts of reduced mass and effective potential energy, and we should also pay attention that the area law is the geometrical description of the conservation of angular momentum in the central field.

The ratio of radiated energy over seismic moment, or the so-called reduced energy, is studied for global deep-focus earthquakes deeper than 70km using the scalar seismic moment in the Harvard CMT catalogue and the radiated energy estimated by NEIC from January 1987 to December 2001.