Doric order proportions. It is suggested that these proportions give the Doric columns a masculine appearance, whereas the more slender Ionic columns appear to represent a more feminine look. This sense of masculinity and femininity was often used to determine which type of column would be used for a particular structure. The most influential, and perhaps the earliest, use of the Doric in Renaissance architecture was in the circular "Tempietto" by Donato Bramante (1502 or later), in the courtyard of San Pietro in Montorio, Rome. Before Greek Revival architecture grew, initially in England, in the 18th century, the Greek or elaborated Roman
Electronic band structure structure has been generalised to wavevectors that are complex numbers, resulting in what is called a "complex band structure", which is of interest at surfaces and interfaces. Each model describes some types of solids very well, and others poorly. The nearly free electron model works well for metals, but poorly for non-metals. The tight binding model is extremely accurate for ionic insulators, such as metal halide salts (e.g. NaCl). To understand how band structure changes relative to the Fermi level in real space, a band structure plot is often first simplified in the form of a band diagram. In a