Through the comparison observations under the conditions of opening and drying environments by using the qualitative and quantitative filter paper, we are trying to reveal the environmental and artificial interfering factors to the soluble CO_2 during the observing process in the deep spring water.

the effect of grinding parameters on grinding force is analyzed by the way of comparative experiment when the ferrite ceramics is ground.

Development and comparative experiment of this machine have been shown that this kind of technology can raise soil moisture, soil thickness, raise the temparature, water-saving, early crop and improve the quality of the products and economical efficiency.

The result of the one-year comparative experiment among college students proves that using “the third culture” as the dominant culture in the class has a better effect.

Develops the Student Chemistry Thought Quality Practice Research Using the Contrast Experiment in the Middle School Chemical Teaching;

By the contrast experiment of 2BMD-12 specific row No-till dill and JD1590 No-till drill in their straw covering field, the capacity of apply fertilizer and ratio of performance and price.

By contrast test,characters of insulating glass sealant filled with mineral oil were compared with that of unfilled with mineral oil,such as durability,heat aging resistance,adhesive ability and the compatibility with hot melt butyl sealant,as well as ultraviolet irradiating resistance.

through the contrast test, research a separable and antirust plastic of solvent polystyrene resin, which is superior corrosion resistance and machine stability.

By contrast tests of feeding form?order?reflection temperature and the change of flame color, the best inventory ratio and experiment condition are obtained.