By analysing the domain knowledge of grape diseases, two kinds of diagnosis models which were based on the BP network and the rule similarity were established.

In this paper,we introduce the concept of similar measure of decision rules,and propose an algorithm based on rough sets for mining interesting default rules-IDRMA.

Minimal non-redundant approximate rules are what with minimal antecedent and maximal consequent and without reducing any information; and an novel algorithm is presented, which can directly extract such rules from the quantitative closed itemset lattice.

The results show that the Mach number and Stokes number are decisive similarity criterion,and the modeling errors of the particle impacting velocity and angle on nozzle wall are less than 5% and 3°,respectively.

The acting force of wind on structure includes inertial force and viscous force,the magnitudes of the two forces are related to the shape of structure,the acting force on a kind of structure is dominated by inertial force,and that on another kind of structure is dominated by viscous force,so neither gravity similarity criterion nor viscous force similarity criterion only can be used to d.

Refering to the deducing method of similarity criterion in classical fluid mechanics,the structural dynamics similarity criterion of large span roofs is detailedly deduced in the paper.

In the environment wind tunnel experiment the dimensionless parameters,initial boundary and plume dispersion characteristics were discussed and the main similitude criteria were acquired.

Similitude criteria for steady operation and non-steady operation of externally pressurized spherical gas bearing with inherent compensation were deduced,which may be considered a corrected form to the similitude criteria of hydrodynamic gas bearing put forward.