Gallium nitride (GaN) nanocrystalline powder has been prepared by sol–gel method. The GaN powder has been confirmed as single-crystalline GaN with wurtzite structure by X-ray diffraction (XRD) and selected-area electron diffraction (SAED), and the diameter of the grains of GaN powder changes...

The creation of microfractures within rock is commonly observed as rock is strained. The presence of these microfractures constitutes damage to the rock, and this damage can reduce the rock’s strength. This paper explores the evolution of rock strength as microfractures within a rock...

Several models of economic behavior currently compete for an explanation of individual wealth accumulation. However, most focus upon a very limited set of saving motives. In this paper we build a general model of economic behavior, set in a stochastic environment, which incorporates multiple...