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51.
The parallel magnetic susceptibility χ of a uniaxial ferromagnet ErCl3·6H2O has been measured between 0.3 and 4.2K and specially near Tc = 0.353 K. The predominant contribution to the Curie-Weiss temperature is due to the dipolar interactions. χ is proportional to ??γ with in the range 10?3 < ? < 5 × 10?2. The γ value, γ = 1.01 ±0.03 is consistent with the theoretical prediction for a uniaxial dipolar ferromagnet. 相似文献
52.
In application of the general procedure defined in I, we analyze various kinds of anomalous effects which could appear either in the leptonic or in the bosonic sector of the reactionse + e ?→ZZ, γZ and γγ: excited electron, excited vector boson or isoscalar partner, anamalous three-neutral boson couplings, residual contact terms involving transverse or longitudinalZ-components. Results are given in view of SLC, LEP and future linear colliders. 相似文献
53.
Francois R. Theobald Jean-Gérard Theobald J.C. Vedrine R. Clad J. Renard 《Journal of Physics and Chemistry of Solids》1984,45(6):581-587
A method to grow single crystals of ammonium vanadate (IV, V) (NH4)2V3O8 has been devised. The crystal structure is tetragonal P4bm; residual factor is R = 0.030. Cell parameters are and . The V5+ atom lies at the center of a triangular pyramide (VO4 tetrahedron) while the V4+ atom is on A 4-fold rotation axis at the center of a square-based pyramide VO5 whose symmetry point group is almost C4v with the short V = O bond lying along the 4-fold axis parallel to the c edge of the tetragonal cell. Crystals are thin platlets with (001) cleavage planes. The platlets have very often a square or rectangular shape limited by {100} or {110} planes. Each single crystal was not large enough to record a good e.p.r. spectrum, but by sticking on the same quartz plate a score of them it was possible to gather enough crystals so to record correct spectra and by orienting the plate to obtain resonance lines separately for g∥ = 1.9263 et gτ = 1.9755. Measurements at 283 K on powder samples gave times for spin-spin relaxation T2 = 0.4 × 10?7s and for spin-lattice relaxation T1 = 1.6 × 10?7s. The magnetic structure is characterized by an exchange narrowing ωe = 3 × 1010rad/s which corresponds to a transition temperature of about 0.5 K. Static susceptibility measurements at high magnetic field show a paramagnetic behaviour with an antiferromagnetic interaction which is interpreted in the magnetic space group P2c4bm as the interaction between V4+ ions from consecutive planes parallel to (001). 相似文献
54.
F.M. Renard 《Physics letters. [Part B]》1976,61(4):365-367
We suggest to look at the reactions e+e?→χ→ hadrons which can occur via 2γ annihilation around 3.4 and 3.5 GeV with a cross-section of the order of a few 10?34cm2 MeV and where the χ could decay mainly into ππηc and ηηc. 相似文献
55.
The 1H and 13C NMR spectra of 2,3-disubstituted exo-5,6- and endo-5,6-bicyclo[2.2.2]octanes, and the corresponding alkanes, have been investigated to determine the effects exerted by an oxirane ring. The 1H NMR study showed that the anti protons, H-7a and H-8a, are significantly shielded and the syn protons, H-7s and H-8s, are deshielded, although to a smaller extent, by the exo-oxirane. An endo-oxirane has practically no effect on the same protons. The stereochemistry of epoxybicyclo[2.2.2]octanes is, thus, easily deduced from 1H NMR data. The 13C NMR study of the epoxy compounds provided an estimate of the value of α, β, γ syn and γ anti effects (to the epoxide oxygen) of an oxirane ring. In these rigid bicyclic molecules, of known geometry, the γ syn and the γ anti effects are of the same value, even though the dihedral angles are very different (0° and 120°). 相似文献
56.
C. Dupas J.-P. Renard G. Fonteneau J. Lucas 《Journal of magnetism and magnetic materials》1982,27(2):152-158
The low field ac magnetic susceptibility has been studied as a function of temperature and frequency in a series of fluoride glasses containing Mn2+, rare-earth ions, or an admixture of the two types. All glasses exhibit magnetic freezing in the 4He or 3He temperature ranges, but the nature of the freezing appears to depend on the local anisotropy. In the case of Mn2+ or Mn2+ -Gd3+ ions, a sharp freezing analogous to that in CuMn was observed. For Ln3+ or Mn2+ -Ln3+ ions (Ln=Dy, Ho), the observed progressive freezing could be of a dynamic nature. 相似文献
57.
58.
J.P. Boucher L.P. Regnault J. Rossat-Mignod J.P. Renard J. Bouillot W.G. Stirling 《Solid State Communications》1980,33(2):171-174
It is shown that magnetic solitons are expected to occur when a magnetic field is applied to a planar antiferromagnetic chain. Neutron inelastic scattering measurements have been performed at low energy on the one dimensional antiferromagnetic compound TMMC. A new fluctuation is observed, around q = π and ω = 0 which is well interpreted in terms of magnetic solitons. 相似文献
59.
Poupart S Boudou C Peixoto P Massonneau M Renard PY Romieu A 《Organic & biomolecular chemistry》2006,4(22):4165-4177
The synthesis and photophysical properties of a new terpyridine-based europium(III) chelate (Eu (TMT)-AP3) designed for peptide and protein labelling in aqueous solution phase is described. In order to obtain a stable, easy to handle, versatile and efficient labelling agent, a reactive aminopropargyl arm has been introduced onto the terpyridine moiety. As preliminary biochemical applications the chelate has been 1) efficiently covalently attached onto a representative biomolecule-monoclonal antibody-and 2) converted into iodoacetamido and aldehyde derivatives, and the photoluminescent Eu (TMT)-AP3 was grafted onto cysteine and lysine amino acid residues respectively. These two different solution phase labelling methods yielded original fluorogenic FRET based probes suitable for "in vitro" detection of caspase-3 protease, a key mediator of apoptosis of mammalian cells. 相似文献
60.