Multi-modal wave propagation in smart structures with shunted piezoelectric patches

The propagation of wave modes in elastic structures with shunted piezoelectric patches is dealt with in this work. The wave finite element approach, which is based on the finite element method and periodical structure theory, is firstly developed as a prediction tool for wave propagation characteristics in beam like structures, and subsequently extended to consider shunted piezoelectric elements through the diffusion matrix model (DMM). With these numerical techniques, reflection and transmission coefficients of propagating waves in structures with shunted piezoelectric patches can be calculated. The performance of shunted piezoelectric patches on the control of wave propagation is investigated numerically with the DMM. Forced response of the smart structure can also be calculated, and based on which the time response of the structure can be obtained via an inverse discrete fourier transform approach. These general formulations can be applied to all types of slender structures. All these numerical tools can facilitate design modifications and systematic investigations of geometric and electric parameters of smart structures with shunted piezoelectric elements.     

Some remarks on rare-event approximation

Two fault-tree analysis methods to compute the minimal cutsets union probability are: the rare-event approximation, and the minimal cutset upper-bound. The rare-event approximation is accurate if all the basic events have low probabilities. The accuracy improvement provided by the minimal cutset upper-bound approximation is negligible     

高压空载线路的可控开、合研究

借助于配有合闸电阻的断路器来限制超高压线路上的开、合过电压的传统方法已被广泛应用的实践证明是很有效的.然而,还可以展望其它的方法,特别是控制断路器瞬间合闸的的方法.研究了超高压线路上采用可控开、合的可能性,并比较了现有的几种解决办法.同时考虑了可能碰到的各种电网特性.详细说明了因断路器的性能造成电网中的过电压水平及所造成的后果.本文的重点放在应用方面的关键问题.     

La nouvelle numérotation téléphonique en France

This paper describes the studies for the organization and the results of the numbering scheme change made in the French network.     

Bracketing of failure path probability in a system with ageing repair times

In practical terms, the distributions of repair times are not known; we have only mean values. We show here that by assuming these distributions to be ageing, it is possible in many cases to bracket availability and reliability using only Mean Times to Repair. Furthermore, this computation can be carried out using Markov models.     

New methods for carrier lifetime measurements in PπN structures

Usual lifetime measurements in $\text{P}{}^{\mathrm{+}}\text{πN}{}^{\mathrm{+}}$ structures determine a parameter which is sensitive to diffusion mechanisms under double injection conditions. This parameter is not characteristic of the recombination mechanism alone.We have proposed two new methods that are not very sensitive to diffusion mechanisms. As the experimental study shows, the measured parameter is the true recombination lifetime in the bulk.     

Shock waves in deformable dielectrics with polarization gradients

The behavior of 1-dimensional shock waves in deformable dielectric materials with polarization gradients, which are non-conductor of heat, is analyzed in the case of quasi-electrostatics. The differential equation governing the amplitude of wave and criteria concerning the polarization gradient and temperature changes across the shock are deduced.     

An experimental method to analyse trapping centres in silicon at very low concentrations

The presence of trapping centres in bulk charge coupled devices can contribute to the charge transfer inefficiency of such devices even when the concentration of the traps is only 10¹⁰cm⁻³. We have developed a measuring method which can detect traps at concentrations down to 10⁸cm⁻³. The measurement yields the concentration, emission time constant and activation energy of the traps.     

Beitr?ge zur Analytik von Farbstoffen XII. Mitteilung Nachweis synthetischer und Curcuma-Farbstoffe im Speisesenf

Zusammenfassung Der Nachweis synthetischer- und Curcuma-Farbstoffe im Speisesenf wird beschrieben. Durch Behandeln der Probe mit Aceton werden Fett, Wasser und acetonlösliche Stoffe wie auch Curcuma-Farbstoffe herausgelöst. Saure Farbstoffe lassen sich anschließend durch Desorption vom pflanzlichen Eiweiß und erneuter Adsorption an Polyamidpulver anreichern, so daß diese nach bekannten Verfahren der Papier- oder Dünnschicht-Chromatographie identifizier-bar sind. Es wird ferner die dünnschichtchromatographische Identifizierung der Curcuma-Farbstoffe beschrieben.

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Contribution to the analysis of dyes XII. Detection of synthetic- and curcuma-dyes in mustard

Summary The detection of synthetic- and curcuma-dyes in mustard is described. The desorption of the dyes from the plant-protein, following separation, purification and enrichment by polyamidepowder or carboxymethyl-cellulose is demonstrated. Further described is the thin-layer-chromatography of curcuma-dyes.

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XI. Mitteilung: Fleischwirtschaft50, 946 (1970).

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Den Herren Professoren Dr. B. Eisten, Dr. O. Neunhoeffer und Dr. H. Thaler sowie Herrn Dr. Rendlen danken wir für Hinweise und Ratschläge, der Deutschen Forschungsgemeinschaft, Farbstoffkommission, gilt unser Dank für die Bereitstellung von Forschungsmitteln.