Supposing that the condition of diffusive sound field is known,a method to handle room sound field is given to avoid the complicated mathematical derivation,using system theory and statistics.

This paper presents sound characteristics of room sound field from architectural acoustics parameters and acoustics parameters and sound system characteristics and speech articulation.

The progress in room acoustics is discussed, including researches on room sound field, sound absorption of room and acoustic quality of hall.

In this paper the sound field properties and the corresponding physical parameters were calculated and analyzed by room acoustical computer simulation program, and the room acoustics scheme proposed by the preliminary acoustical design was discussed.

This article gives a survey on the current technology of the computer simulation of room acoustics,as known as the construction of virtual acoustical environment.

With the development of room acoustics,the indexes for the description of sound fields in rooms have been expanded to a series of parameters characterizing time,energy and space.

In view of the existing defects in anaerobic landfills, especially the difficulty of their leachate treatment, laboratory simulation and mathematics modal of semi-aerobic landfills are introduced to investigate the leachate quality, factors influencing it and its degradation rules.

Through laboratory simulation study,the feasibility and reasonableness of leachate treatment with semi-aerobic aged refuse bio-bed are developed.