Backward K10 production in the reaction π−p→Λ0K+π− at 9 and 12 GeV/c

We have analysed about 85 000 fast Λ⁰ events, obtained in a fast proton triggered experiment performed at the CERN-Ω spectrometer at 9 and 12 GeV/c incident π^? beam. Nearly 2500 Λ⁰K⁺π^? events have been isolated. We find strong production of quasi-two-body processes $\text{Λ}{}^0\text{K}{}^{10}$ and $\text{∑}{}^{\mathrm{1?}}\text{K}{}^{\mathrm{+}}$ consistent with u-channel hyperon exchange. Results on Λ⁰ polarization, K¹⁰ decay parameters and differential cross sections are given for $\text{Λ}{}^0\text{K}{}^{10}\text{(892)}$ and $\text{Λ}{}^0\text{K}{}^{10}\text{(1430)}$ final states. A comparison is made with the associated backward $\text{Λ}{}^0\text{(1520)}\text{K}{}^{10}$ production seen in the four-prong reaction π^?p→pK^?K⁺π^? obtained in the same experiment.     

Electrode effects in electrical measurements in SiO thin films

We report results obtained from thermally stimulated current and capacitance measurements of metal-SiO-metal structures having different metals for the electrodes. Dependence of relaxed charge on the polarized electrode suggests the existence of space charge near the metal-insulator interface. The measurements of capacitance under superimposed DC voltages support this interpretation and show that space charge is not negligible at high fields. The density of lacalised states evaluated from the data is of the order of 10¹⁷ cm^?3     

Chalcogen adsorption on Ni(100)

The successive stages of the oxidation of Ni(100) have been investigated by angle-resolved uv photoemission. The adsorption spectra are very similar to that measured previously for the same surface saturated with sulphur. Results are interpreted using recent theoretical calculations. It is found that this interpretation can be extended to the other chalcogens adsorbed on Ni(100). When increasing oxygen exposures, photoemission spectra have shown a continuity of the electronic character in the oxidation process.     

The distribution of high multipole strength in finite nuclei

The multiple strength associated with the operator r^LY_L for L? 6 is distributed at much lower energies when calculated for nucleons moving in a finite potential well than when a harmonic oscillator well is used. The residual interactions would push these isoscalar resonances further down.     

Design and performance of millimeter-wave end-coupled bandpass filters

The design and performance of millimeter-wave microstrip/suspended-stripline end-coupled bandpass filters are presented. Filters in Ka-band (26.5 to 40 GHz) and W-band (75 to 110 GHz) using suspended-stripline and microstrip have been designed. Good agreement between the experimental results and those predicted theoretically was observed. Measured passband insertion losses of less than 1 and 0.5 dB have been achieved in W- and Ka-band, respectively. An extremely wideband waveguide-to-microstrip transition with an insertion loss of 0.25 dB over the full W-band is also presented.     

Bornes quasi-inferieures et bornes superieures de la pression de ruine des coques de revolution par la methode des elements finis et par la programmation non-lineaire

This work is concerned with rigid-plastic limit analysis of shells of revolution subject to rotationally symmetric loadings. These shells, of arbitrary shape, are discretized into a series of finite elements, each being a conical shell. The von Mises condition, valid for sandwich shells, is used to compare the results obtained with existing values. After assembling the finite elements, the limit analysis program is reduced to a simple application of the non-linear programming technique where both the sequential unconstrained minimization technique (SUMT) and feasible conjugate direction (FCD) are utilized respectively for statically admissible and kinematically admissible approaches. Therefore, upper bounds and lower bounds of the collapse loads are found for some sample problems : conical, spherical, ellipsoidal, torispherical shells etc. These numerical results are illustrated and compared with existing ones described in the literature.     

A new nucleophilic addition/ring-closure sequence. Enantioselective synthesis of 3-deoxy-8-oxatropanes

[reaction: see text] A study of new nucleophilic addition/ring-closure (NARC) sequences has resulted in the development of a stereoselective synthetic route to 3-deoxy-8-oxatropanes. The new sequences consisted of either a syn or anti aldol addition, employing an omega-alkenoyl sultam, followed by two-step bicyclic ring construction involving, consecutively, ring-closing metathesis and intramolecular oxymercuration.