A study of the photoneutron contribution to the giant dipole resonance in doubly even Mo isotopes

By using a variable monochromatic photon beam, the partial photoneutron cross sections σ(γ, n) + σ(γ, pn), σ(γ, 2n) and σ(γ, 3n) are determined in the region of the giant dipole resonance for the doubly even Mo isotopes ⁹²Mo, ⁹⁴Mo, ⁹⁶Mo, ⁹⁸Mo and ¹⁰⁰Mo. Measured integrated photoneutron cross sections are compared with available integrated photoproton cross sections as a function of A. Broadening of the giant dipole resonance as A increases is observed in good agreement with the predictions of the dynamic collective model. A tentative study of some isospin splitting effects is also carried out.     

A measurement of single electrons,electron pairs,and associated phenomena,in proton-proton collisions at the CERN ISR

Measurements of single-electron production in proton-proton collisions at the CERN ISR are presented for five centre-of-mass energies √s = 23.5, 30.6, 44.8, 52.7, and 62.4 GeV. The invariant cross sections for single electrons with transverse momenta of 0.60 to 4.7 GeV/c are given. Measurements of electron-positron pairs and measurements of charged hadrons produced in association with the single electrons, are also reported.     

Majorations de la constante de poincaré relative au problème de la membrane-domaines étoilés

Résumé Des nouvelles majorations de la constante de Poincaré sont établies pour des domaines étoilés. Cette constante est l'inverse de la fréquence fondamentale pour le problème de la membrane.

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Summary New bounds of Poincaré constant are given for starshaped regions.This constant is the inverse of the fundamental frequency for the free membrane problem.

     

The vacuum ultraviolet spectra of HCN,C2N2, and CH3CN

Quantitative vacuum ultraviolet absorption spectra for HCN, C₂N₂, and CH₃CN have been obtained over the wavelength range 60 nm ? λ ? 160 nm. Where comparison is possible, our measurements of the absorption coefficients for HCN and C₂N₂ are consistent with previous studies. Because of the superior resolution of this work (0.05 nm), vibrational assignments in the valence and Rydberg transitions of HCN have been extended while higher members of the Rydberg series in CH₃CN have been identified.     

Lasing ability of naphthyl 1,3,4 oxadiazole molecules in relation with their structures: Application to the design of new UV dye laser

We have shown that the lasing properties of naphthyl 1,3,4 oxadiazole derivatives are directly related to the position of the forbidden transitionS ₀→¹ L _b of naphthalene with respect to the first allowed transitions. The combination of theoretical and experimental results allows us to predict which compounds are most likely to exhibit a laser effect according to the nature and the position of their substituants. We have successfully applied this approach to the following compounds: αNPD, βNPD, αNND, βNND, βNBD, and αNBD. In particular we reported the first observation of a laser effect for αNBD and βNBD in the UV at 3830 Å and 3758 Å.     

Hétérocycles contenant du phosphore. XXXII. Etude de l'action des phosphorhydrazides sur les orthoesters,l'anhydride acétique et l'acide formique

The reaction of phosphodi- or trihydrazides with orthoesters affords mainly 2,3,4,5-tetrahydro-1,2,4,5,3-tetrazaphosphorines and sometimes 4-amino-1,2,4,3-triazaphospholidines. These 1,2,4,5,3-tetrazaphosphorines present a prototropy which explains different pathways of the reaction of these derivatives with formaldehyde or acetone, The structure of all heterocycles which were obtained was established by nmr spectra.     

Etude de la structure des hydroxydes de gallium et d'indium par thermogravimétrie et absorption infrarouge

Zusammenfassung Der Vergleich der Absorptionsspektren von GaOOH und In(OH)₃ im IR zwischen 1 und 30 mit Spektren von Kristallen des gleichen Typus läßt die Valenz- und Deformationsschwingungen der Hydroxylgruppen erkennen.

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Summary Comparison of the infrared absorption spectra, between 1 and 30, of GaOOH and In(OH)₃ with those of crystals of the same type gave evidence of valence vibrations and deformation of the OH groups.

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Résumé La comparaison des spectres d'absorption infrarouge entre 1 et 30 de GaOOH et de In(OH)₃ avec ceux de cristaux de même type, met en évidence les vibrations de valence et de déformation des groupements OH.

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En l'honneur du Prof.A. A. Benedetti-Pichler, respectueusement.     

Representations of certain solvable Lie groups on Hilbert spaces of holomorphic functions and the application to the holomorphic discrete series of a Semisimple Lie group

If ($\text{b}$,$\text{j,?}{}_0$) is a normal j-algebra and b^? = {X + ijX;X∈b} then $\text{b}$^? is a positive polarization at /tf₀ in the sense of Auslander and Kostant. The representation $\text{ρ(?}{}_0\text{,b}{}^{\mathrm{?}}\text{)}$ defined as in the orbit theory is shown to be given on a space of holomorphic functions on a Siegel II domain. The Fourier transformation is shown to be an intertwining operator between $\text{ρ(?}{}_0\text{,b}{}^{\mathrm{?}}\text{)}$ and $\text{ρ(?}{}_0\text{,)}$ for a suitable real polarization $\text{h}$. These explicit results are used to deduce the Harish-Chandra conditions defining the holomorphic discrete series of a Semisimple Lie Group.     

Application de la chélatométrie au dosage des esters et chlorures de mono-esters oxaliques

Esters and chlorides of oxalic mono-esters can be estimated volumetrically. After saponification precipitation is carried out by means of a calcium chloride solution, the excess of which is measured by chelatometry.