Hyperbolic paraboloid surfaces or saddle-shaped materials can exist in two equilibrium shapes when the saddle shape reverses on itself and, therefore, be used as structural elements of new stimuli-responsive and shape-changing materials. Here we propose a fast easy approach to nanoarchitectonics graphene oxide nanosheets form curved interfaces. Our technology involves computer-aid design, three...

Spanish architect Antoni Gaudı́ drew on natural precedent to create fantastic organically inspired designs. This paper examines some common motifs in his works, and demonstrates how simple geometric operations can be applied to polyhedral models to achieve similar results. The importance of the partial hyperbolic paraboloid surface (or hypar) is discussed in this context. r 2007 Elsevier Ltd. Al...

this paper seeks to answer the question whether the constitutional revolution of 1905-1911 in iran was a democratic revolution or social revolution? this discussion has been explained from the view point of the political sociology, relying on the moore's theory. studies indicate that the constitutional revolution in all periods has had the features of democratic revolution for the followin...