Time-dependent functional Schrodinger picture approach to many-particle systems

A time-dependent many-body theory for many-particle systems is formulated using the functional Schrodinger picture. Taking a Gaussian trial wave functional and using the variational principle, the equations of motion are obtained. The equations of motion are solved in the small oscillation regime to yield the generalized RPA results. The electron-hole excitation, the collective plasma oscillation for the paramagnetic state, the Stoner excitation and the spin wave for the ferromagnetic state are derived and discussed. As a further test on the versatility of the present method, the formalism is applied to the bound states of the exciton problem and shown to yield the governing equation in a straightforward manner.X111sciescopu

A knowledge-based parametric design system for drawing dies

[[abstract]]The design of drawing dies is a very complex and knowledge-intensive process. This paper describes a knowledge-based parametric design system for drawing dies which requires only a minimum set of parameters to be set before it is able to complete the design of the main components of a die, such as upper dies, lower dies, and blank holders. This minimum set of parameters includes blank sizes, die faces, punch open lines, drawing strokes, and press data. This design system implemented on top of the Pro/E CAD software consists of a drawing die knowledge base, a subcomponent inferencer, a dimension calculator, a subcomponent generator, a system coordinator, and a user interface. We use the design of drawing dies for inner wheel house as a concrete example to show that our system can greatly improve the design quality while reducing the development time and cost