- Andrew Johnson (Wikipedia)
Andrew Johnson (December 29, 1808 – July 31, 1875) was an American politician who served as the 17th president of the United States from 1865 to 1869. He assumed the presidency following the assassination of Abraham Lincoln, as he was vice president at that time. Johnson was a Democrat who ran with Abraham Lincoln on the National Union Party ticket, coming to office as the Civil War concluded. He favored quick restoration of the seceded states to the Union without protection for the newly freed people who were formerly enslaved as well as pardoning ex-Confederates. This led to conflict with the Republican-dominated Congress, culminating in his impeachment by the House of Representatives in 1868. He was acquitted in the Senate by one vote.
- Electron hole (Wikipedia)
In physics, chemistry, and electronic engineering, an electron hole (often simply called a hole) is a quasiparticle denoting the lack of an electron at a position where one could exist in an atom or atomic lattice. Since in a normal atom or crystal lattice the negative charge of the electrons is balanced by the positive charge of the atomic nuclei, the absence of an electron leaves a net positive charge at the hole’s location.