| 摘要 |
Spherulitic crystals, such as spherical nitroguanidine, are prepared by super cooling and stirring a hot saturated solution in dipolar aprotic solvents at a specific stirring rate epsilon </= 0.1 W/kg, adding seeding grains of the same substance of at most 50 mu m, the addition of seeding grains being carried out prior to the temperature being reached at which self-nucleation begins. Instead of the addition of seeding grains, spherulitic crystals can also be obtained at the same stirring rate by addition of polar ionically active substances or by addition of organic acids.
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