Flat smectic liquid crystal display panel

First results of a direct-view flat-panel display for computer terminal applications are presented. This panel uses an effect which has already been reported by the authors for a TV projection display.     

Gonflement du nickel irradie par des ions Ni+ de moyenne energie

After briefly summarising the advantages and drawbacks of bombardment with heavy ions, we describe the experimental apparatus we used for studying swelling in nickel. Next we discuss the problems connected with the determination of the number of atoms displaced during ion-bombardment.We studied the influence of the following parameters on the swelling of nickel: temperature, gas content, fluence, ion energy. Swelling varied with temperature and increases to a maximum at 620°C for 500 keV nickel ions. Prior helium-loading of the samples (10ppm) reduces swelling and the mean void size and increases the number of cavities. Swelling grows linearly with fluence up to 25 displacements per atom. The number and size of voids grows rapidly in the early stages of irradiation.We explain how helium reduces swelling in our experiments, and we determine how far the fluences calculated for ion-bombardments need to be corrected to allow valid comparisons with in-pile results.     

An estimation of the film-penetration model parameters

It it shown in this paper that the process of evaporation of liquids into a turbulent gas flow in a wetted-wall column can be represented by the film-penetration model. The numerical values of the two parameters S and L of this model, estimated from mass transfer data, appear to be well defined functions of flow conditions. The surface renewal mechanism used in the considered mass transfer model was shown to be consistent with the momentum transfer concept.The results may be used to predict mass transfer processes with chemical reactions in similar flow systems, by applying the theoretical developments using the film-penetration theory [7–10].The same procedure may be used to estimate the film-penetration parameters in other flow systems, such as the flow of liquid films in a wetted-wall column, or other complicated system such as stirred tanks, bubble columns, packed columns etc.     

Improvement of dispersion resistance in analog radio-on-fiber upconversion links

Dispersion fiber sensitivity in optical microwave upconversion links is investigated. Simulations are carried out to calculate output optical spectra and to evaluate mixing power as a function of fiber length for different upconversion systems using dual drive/standard Mach-Zehnder modulators or an unbalanced Mach-Zehnder interferometer (UMZ). The latter solution prevents complete cancellation of mixing power because of the asymmetric double sideband optical spectrum detected at the output of the UMZ. It is shown that an optimum value of the linewidth enhancement factor of the laser diode can be found to minimize degradations of the mixing power along the fiber.     

Dissolution of polypropylene in organic solvents: 3. Effect of molecular weight of polymer

Previous papers in this series have described the main features of the dissolution of solid polypropylene in organic solvents. The molecular weight of the polymer is now considered in connection with the rate of dissolution, the density of the specimens and the temperature of the dissolution experiments. A straight line relationship is obtained on plotting the log of the rate of dissolution (for fixed temperature and specimen density) against the log of the viscosity-average molecular weight.     

Reduction electrochimique de propene nitriles substitues—III alkyl(aryl)oxy-3 phenyl-3 propene nitriles Z et E

The preparation and the separation of E- and Z-isomers of 3-alkyl(aryl)oxy-3-phenylpropenenitriles are described. Configurations are assigned by nmr.In aqueous-organic media Z-isomers are more easily reduced than E-isomers. In anhydrous acetonitrile differences between E$\text{1}\text{2}$ of E- and Z-isomers are smaller or null.Polarography, cyclic voltammetry and macro-scale reductions with identification of products permit us to propose a reduction mechanism. If Taft's constant σ* of R group is negative the CC double bond is reduced with formation of 3-alkyl(aryl)oxy-3-phenylpropanenitriles. If σ* is positive the intermediate radical-anion loses RO^? ion; cinnamonitrile is formed but immediately reduced, either to in 3-phenylpropanenitrile, or to in 3,4-diphenylhexane dinitrile.It is possible to get hydrodimers while conserving OR group.     

Method for the synthesis of semitransparent wide band dielectric mirrors

A general method for the numerical design of wide band dielectric mirrors with non-zero transmission is given. The values of the optical parameters for twenty mirrors designed by this method are presented and discussed.