Global approximate Newton methods

Summary We derive a class of globally and quadratically converging algorithms for a system of nonlinear equations,g(u)=0, whereg is a sufficiently smooth homeomorphism. Particular attention is directed to key parameters which control the iteration. Several examples are given that have been successful in solving the coupled nonlinear PDEs which arise in semiconductor device modelling.     

Ion-implanted target for soft x-ray laser investigations

Ion-implantation has been used to make a target suitable for the investigation of soft X-ray laser action via resonant photo-pumping. Neon was implanted on one side of a thin aluminum foil and sodium fluoride was coated on the other side. A 100 picosecond laser pulse at 2 × 10¹⁴ W cm^-2was used to irradiate the neon side, and 330 ps later the sodium fluoride side was irradiated with a similar pulse. X-ray spectroscopy was used to measure the state of ionisation of the neon, and the inferred electron temperature was compared with a one-dimensional computer simulation. The spectral brightness of the pumping radiation was also estimated.     

Face dependent surface energies of simple metals

Using a simple ansatz for the $\text{inhomogeneous}$ screened linear electron gas susceptibility, we obtain the face dependent surfaces energies, σ, of the simple metals, through second order. In contrast to results of the first-order Lang-Kohn method and the $\text{one-dimensional}$ variational values of Monnier and Perdew, we obtain $\text{weakly}$ face dependent σ values consistent with experiment. Our results hinge on two previously neglected considerations: (i) ion induced inhomogeneity of the bulk electron density prior to cleavage and (ii) ion induced electron density inhomogeneity in the surface region after cleavage.     

Alcoyl-gluco-alcaloides: nouveaux composes isoles de pauridiantha lyalii brem (rubiacees)

La structure destrans fe´ruloyl-6′ ettrans sinapoyl-6′ lyaloside, isole´s des feuilles dePauridiantha Lyalii, ae´te´de´termine´e par de´gradation chimique et par spectroscopie (Masse, RMN¹H et¹³C). Ces compose´s font partie d'un groupe structural caracte´rise´par un enchai?nement alcaloide-monoterpe`ne-ose-acide (C<sub>6</sub>-C<sub>3</sub>), groupe dont un seul repre´sentant semble avoire´te´isole´jusqu'a`pre´sent. Leur fonction dans le ve´ge´tal est discute´e.     

Ion photodesorption from argon multilayers

Received: 16 June 1997/Accepted: 26 October 1997     

On the use of photoelastic composite models

Emphasis in the paper is placed on establishing the validity of employing photoelastic composite models to study assumptions used in composite-material analysis. Two approaches for the derivation of material constants for plane-stress layered composite materials are presented. Basic assumptions of the theories are studied. The theoretical and experimental equivalent moduli for test specimens loaded in tension and in shear are also compared.