1. Use magnetic field lens again, two kinds of electron lens elaborate respectively below form and principle.

2. The observation of scan electron lens shown that the result, the foam has the ideal structure.

3. The principle of differential algebraic method is applied to calculate arbitrary high order aberrations of electrostatic electron lens systems.

4. Methods With 20 postoperative samples of colon carcinoma, resin embedded semi thin section were prepared for observation of location under optical lens and ultrathin section under electron lens.

5. For SMPDP, the structure of discharge cell is very important to the focus of the ions as an electron lens.