Clinical and Ultrasonographic Features of Secondary Intussusception in Children
Objectives ::: The aim of this study was to review the ultrasonographic features of secondary intussusception (SI) in children and assess the value of ultrasound in the diagnosis of pediatric SI.
Abstract In situ composites can be obtained either by unidirectional eutectic solidification or by unidirectional solid- state decomposition. Techniques in the latter category are dealt with in this review. The solid-state growth methods may be classified, according to the state of the starting material, into (a) eutectoid decomposition, (b) discontinuous precipitation, or (c) growth from the noncrystalline state. Common to the three processes is the duplex microstructure which occurs, permitting alignment during growth in a temperature gradient. The author reviews the theory of the transformation, the experimental techniques, and the empirical parameters which have been reported in the literature. Emphasis is placed upon the relationships between interphase spacing and growth rate, and upon the potential discrepancies between growth rate and pulling rate.