This study demonstrates the accumulation of electron-induced secondary electrons by utilizing a simple geometrical configuration of two branches of a charged insulating biomaterial. The collective motion of these secondary electrons between the branches has been visualized by analyzing the reconstructed amplitude images obtained using in situ electron holography. In order to understand the collective motion of secondary electrons, the trajectories of these electrons around the branches have also been simulated by taking into account the electric field around the charged branches on the basis of Maxwell’s equations.

The charging effects of microfibrils of sciatic nerve tissues due to electron irradiation are investigated using electron holography. The phenomenon that the charging effects are enhanced with an increase of electron intensity is visualized through direct observations of the electric potential distribution around the specimen. The electric potential at the surface of the specimen could be quantitatively evaluated by simulation, which takes into account the reference wave modulation due to the long-range electric field.

Nanoparticles of iron carbides (Fe3C and χ-Fe2.5C) wrapped in multilayered graphitic sheets were synthesized by a developed method in which an electric plasma was generated in an ultrasonic cavitation field containing thousands of tiny activated bubbles in liquid ethanol. Annealing changed the phase composition, structure, and size of the carbon nanocapsules as most of the iron carbides decomposed into the α-Fe phase and graphite. Powder samples annealed at 873 and 973 K have maximal saturation magnetization values equal to 80.6 and 83.4 A m2/kg, respectively, which is approximately 40% of the value of bulk iron. Using this method, it will be possible to synthesize nanoparticles of a metal of choice encapsulated by graphite shells by selecting appropriate materials for the ultrasonic tip and electrodes.