Let D be a bounded convex domain of the complex plane. We study the problem of whether the fundamental principle holds for analytic function spaces on D invariant with respect to the differentiation operator and admitting spectral synthesis. Earlier this problem was solved under a restriction on the multiplicities of the eigenvalues of the differentiation operator. In the present paper, we lift this restriction. Thus, we present a complete solution of the fundamental principle problem for arbitrary nontrivial closed invariant subspaces admitting spectral synthesis on arbitrary bounded convex domains.
A new method for the measurement of residual stresses in sheet materials is presented. The method is based upon the measurement of the curvature resulting from progressive removal of uniform layers from the surface of the specimen by chemical etching. The curvature is obtained from electronic speckle pattern interferograms (ESPI). As an illustration, a thin cold-rolled steel sheet was tested. Surface residual stresses were measured in as-received and heat-treated specimens. Results were found to be within the range given by x-ray diffraction measurements and show that annealing is an effective procedure for the reduction of residual stresses.
A new high-performance electrostatic charged particle energy analyser has been developed with the purpose of combining all the diverse advantages of the currently available types of spectrometer into a single instrument. This paper indicates how the instrument evolved directly from the requirements of the design specification. The resulting device acts as a bandpass filter and consists of a retarding grid section. followed by an energetically dispersing region formed by a continuously decelerating. focusing field. Design aims. basic theory. construction and experimental evaluation are presented. Important performance parameters of the new design are its high signal-to-noise ratio. characterised by a high transmission ( 15%) and low spurious signal collection: high available energy resolution (0.03'%) FWHM): electrical adjustment of bandwidth:and comparative insensitivity to source position and external magnetic field. Capability to produce high-quality Auger spectra is demonstrated. emphasising the advantages of trade-off between spectral resolution and sensitivity.
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