Application of fuzzy control technique to secondary return air systems in large spaces;

Further the influence in jet s ventilation of secondary return air on the zones comfort is studied.

The model of desodium by hydration of CaO under ordinary pressure from sodium-bearing siliceous residue in alumina production by sintering process is derived by quadratic regression orthogonal design.

Four irrigation schedules with higher yield and good comprehensive character for mango planted in sandy loam were preliminarily selected through quadratic regression orthogonal combination design process.

The quadratic regression equation was better than linear regression equation with higher precision although both of the regression equations could obtain acceptable test results.

An accident analysis caused by a secondary circuit connection wrong;

Faults frequently found in secondary circuit of circuit breaker and improvements;

The methods of looking up the fault of secondary circuit;

Analysis of voltage transformer secondary loop grounding point;

Secondary loop includes current transformer,voltage transformer,secondary wiring,electronic energy meter and burden monitoring units.

In view of occasional erroneous wiring of current often met with in the power industry, the paper discusses the mutual influence among different parameters of current transformers, as well as the effect of erroneous wiring of transformer terminals on the secondary loop current, on secondary load impedance and an the reliability of protection by relays.