The shadow and block efficiency of the heliostats in the heliostat field considering the shadows of the tower in the tower Solar Power Plants(SPPs)has been obtained by geometry optics.

Comparison analysis of three-dimentional tray and two-dimensional tray of gas-liquid mass-transfer in tray column;

Mechanical defoaming in downcomer of tray column;

A mathematical model for NO_x absorption in plate column;

Application of plate column and packed column in oil refining and its cost analysis;

Analysis on the effect factors of plate column' s operation;

Some newly developed trays and their industrial applications abroad have been presented,followed with the analysis of the trend and emphasis of development of tray towers.

In this paper, the structure chaacteristics of the new tray tower developed in ecent years are summarized.

The characteristic and developing tendency of packed tower and tray tower are discussed, and makes a comparison in properties between the two types of tower.

In this paper the entrainment phenomenon in a plate tower in operation hasbeen discussed,and the entrainment of the sieve plate and the valve tray is taken as the focalpoint in analysis.