First of all, there is a concept in materialization called: solution dependence, that is, when the solution contains a certain amount of solute, compared with pure solvent, the freezing point drops, the boiling point rises, and the osmotic phenomenon caused by osmotic pressure. Frozen pears contain sugar, so the freezing point is lower than water. The temperature of cold water is higher than that of frozen pears, so use cold water to thaw pears. When the sugar solution in the frozen pear is dissolved, the actual temperature of the pear is still low, even lower than the freezing point of water, so when the inside of the frozen pear is thawed, its surface will still freeze. The sugar in pear is mainly located in the big vacuole, which contains a high concentration of solution, so the temperature drops and the aqueous solution freezes due to intermolecular hydrogen bonds, which has a destructive effect on plant cells. So when it is frozen, in fact, the intercellular structure inside the frozen pear is unstable and even chaotic. Due to the difference of solution concentration and the destruction of membrane structure, under the action of osmotic pressure, the concentration of cell membrane and internal organelles such as large vacuole membrane will tend to be consistent, so the contents of large vacuole will be released, the cell structure will be destroyed, and pears will become soft. Because the sweetness will change with the change of temperature, I went to check, and the sweetness of fructose will increase obviously with the decrease of temperature, while other sugars will not change much. So the sweetness that the supervisor said should be caused by fructose in pears. The above is the principle of thawing frozen pears according to the amount of solution. As for industrial applications, I know that distillation, rectification, membrane and other separation industries are commonly used. It seems that these things don't match, but the core of the principle is the dependence of the solution.