Common drug identification methods:
Non-tapping screws are machine Screw, the pieceworker to be fastened must be tapped with taps in the screw hole in advance to match the screw threads.
The difference between tooth screws and other screws depends on whether they can be used together with nuts. Tooth screws can be used with nuts. And relative to the screws of other teeth, there are self-tapping screws. The nut of this kind of screw has no bow teeth. As for the standard teeth and fine teeth are only different pitch, it is the nut of the machine screw
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Intuitive method and intuitive method for powder pesticides, first look at the appearance of the drug, if it has been significantly damp and agglomerated, the taste of the drug is not strong or have other odors, and can be smashed into a group by hand, indicating that it has basically failed; for the emulsion pesticide, the bottle is first If the turbidity of the liquid is unclear or stratified (ie, oil-water separation), the precipitate is naturally or floc suspended, indicating that the agent may have failed. The heating method is used in powder pesticides. Take 5-10 grams of pesticides and heat them on a piece of metal. If a large amount of white smoke is produced, and there is a strong pungent smell, it means that the medicine is good. Otherwise, it means that it has failed. The floating method is used in combination with wettable powder pesticides. First take 200 grams of clean water, then weigh 1 gram of pesticide, gently and evenly spread on the surface of the water to observe carefully. In 1 minute, it is wet and can sink to the water is the non-failed pesticide, otherwise it is a failed pesticide.
Suspension suspension method is used in wettable powder pesticides. Take 30-50 grams of pesticides, put them in a glass container, first add a small amount of water to make a paste, then add 150-200 grams, stir well with water, and let stand for 10 minutes to observe. The pesticides that have not failed are well soluble. The suspended particles in the liquid are fine, the sedimentation rate is slow and the amount of sedimentation is small, and the pesticide is reversed. The oscillating method is used in emulsion pesticides. For the pesticides that have oily water layer, first shake the vial with force and let it stand for 1 hour. If it still stratifies, the agent has deteriorated.
Hot melt hot melt method is used in emulsion pesticides. Put the pesticide with the precipitate into the warm water (the water temperature should not be too high, preferably 50 ° C -60 ° C), after 1 hour, if the sediment slowly dissolves, the agent has not expired, and the precipitate is dissolved. It can be reused afterwards; if the precipitate is difficult to dissolve or dissolve, it means it has failed and can no longer be used.
The dilution method is used in combination with emulsion pesticides. Take 50 grams of pesticide, put it in a glass bottle, add 150 grams of water, and shake it vigorously for 30 minutes. If the liquid is average milky white, it will be a failed pesticide, and the more the upper layer of oil, the worse the drug.