The first paragraph: introduction to background knowledge
The teacher of the Environmental College of Shaanxi Normal University needs to do the experiment of wood. The requirement is to grind the xylem into powder, and then measure the heavy metal and the annual ring in the wood by means of stable isotope. Under normal circumstances, the wood structure of Chinese fir (fir, spruce, cypress) is crunchy. It is easy to grind the steel tank by using Shanghai Jingxin multi-sample tissue grinder. However, the teacher should remove the pollution of heavy metal on the sample and test it with plastic tank. .
The second paragraph: Describe the principle of sample research <br> The wood structure of Chinese fir (fir, spruce, cypress) is crisp, and it is very easy to grind with steel balls and steel cans. To remove the pollution of heavy metals on samples, ceramic beads and plastics are used. The cans were tested. Still the same principle, the sample and ceramic beads are added to the plastic can, placed in the instrument, set the frequency and time, and then ground.
The third paragraph: sample specific grinding method
Experimental Procedures <br> Step 1: Sample and XX ml of ground plastic cans Step 2: Place the sample in a XX ml plastic can, then place the plastic can on the net letter grinder.
Step 3: Set the parameter grinding frequency XX HZ, and the time XX can be ground into powder.
Step 4: Remove the sample from the net letter grinder and open the plastic can to pour out the sample.
After grinding the powder sample, the grinding fineness can meet the experimental requirements.
Note: The sample must be lyophilized in the lyophilizer for more than XX hours. Otherwise, the fibers in the wood are not easy to be ground and pulverized, and the grease in the xylem is easily attached to the grinding tank wall and the grinding beads. It is not easy to clean and collect the sample.
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