Using the time domain separation technology through edge diffraction and virtual instrument test technology,we do the experimental study of how the free-field method is applied to structure-borne sound insulation measurement.

The acoustic filed is calculated in different aspects, influence on the free field analyzed under different conditions, and useful conclusions obtained.

The performance of the box is checked by free field tests on shaking table.

The analysis of free sound field in the anechoic room;

The test data are interpreted of the free-field stress wave of a series of chemical explosion from 1 to 150 kg TNT in granite.

In underwater acoustic engineering,improving precision of acoustic measurement for materials in free-field is very important in design of acoustic stealthy of underwater vehicle.

Simulation of ground motion on free field of arch dam;

Firstly, this paper introduces the theory of vibration, then the propagation of train-induced vibrations in free field was studied by using numerical method.

In this paper,the propagation of train-induced vibrations and their influence rules in the surrounding free field and building are systematically analyzed.

In consequence it has resulted in a sense of disillusionment over the myth of the "free market".

The three major socialist transformations were carried out simultaneously with the withdrawal of market regulation mechanism from the economic operation and one of the expressions of this withdrawal from rural economy was the closing of free markets.