We study the time-periodic solutions to systems of conservation laws with ellipticity. It is shown that under time-periodic boundary condition, the system admits at least one global time-periodic solution bounded uniformly with the same period.

abstract background: the radiographic image accuracy depends on the x-ray film information visibility. good visibility is found by good contrast. radiation exposure parameters (kvp, mas) and film processing conditions have impact on contrast. in dentistry radiography machines, exposure time and processing procedure are set by radiographer. no optimized exposure time and processing conditions ma...

there has been extensive work on the existence of periodic solutions for nonlinear second order autonomous differantial equations, but little work regarding the third order problems. the popular poincare-bendixon theorem applies well to the former but not the latter (see [2] and [3]). we give a necessary condition for the existence of periodic solutions for the third order autonomous systems, t...