Stress functions and internal stresses in linear three-dimensional anisotropic elasticity

A stress function method is presented in order to give a general solution of the incompatibility problem of three-dimensional linear anisotropic elasticity theory. A relation between the internal stress tensor in terms of derivatives of a sixth-order stress function tensor will be derived. Using this formulation the so far open problem of the representation of the second-order stress function tensor by the fourth-order stress function tensor in anisotropic elasticity theory is solved in general.     

Practical mm-Wave pHEMT Frequency Multiplier

Details on a broadband MMIC frequency doubler targeting the MVDS market are presented. The design evolution from an individual pHEMT device to the complete practical doubler realisation is discussed. The doubler MMIC, which has been fabricated using the GMMT H40 GaAs process, has been evaluated in a customised package. An output power of +10 dBm at 40 GHz has been achieved with an associated conversion gain of 1.5 dB. The measured and predicted performance responses are compared. This chip is ideally suited to use in a number of emerging mm-wave applications.     

Scattering theory for Stark Hamiltonians

We give an introduction to the spectral and scattering theory for Schr?dinger operators. An abstract short range scattering theory is developed. It is applied to perturbations of the Laplacian. Particular attention is paid to the study of Stark Hamiltonians. The main result is an explanation of the discrepancy between the classical and the quantum scattering theory for one-dimensional Stark Hamiltonians.     

Loss of HX from 2-haloethanol ions

Contrary to the behavior of 1-haloalkanes, the loss of HX from 2-chloro-and 2-bromo-ethanol involves a 1,2 elimination.     

Thomson Scattering Applied to a Noisy Radiative Plasma

Thomson scattering with a 1.5 ms long pulse mode 20 J ruby laser has been applied to a radiative argon plasma with electron densities n_e from 2.5 10¹⁹ m^?3 to 1.5 10²⁰ m^?3 and an electron temperature T_e of about 3 eV. Photon counting techniques have been used. The accuracy of n_e and T_e to be reached is about 5% after 10 shots. The signal to noise ratio S/N has been optimized by the use of optical filters and a special purpose grating. The effects of these elements on S/N have been calculated. The entrance angle, transmission and quantum efficiency have also been optimized. A comparison between 5 possible laser systems, including a normal mode and a Q-switched mode ruby laser, has been carried out.