Une tombe à incinération du IIe s. ap. J.-C. à Haussy (Nord).

Abstract

A IInd Century A.D. Cremation Grave in Haussy (Nord). In 1991, during the digging of ditches along the 955 departmental road on the territory of Haussy, a farmer discovered a Gallo-Roman cremation grave. This pit dug in a field had been fitted out : a limestone slab was laid on the east side. The bone remains are placed in an urn and accompanied by 14 offerings among which a white pottery figure representing a Venus « sous édicule », a coin, a pair of fibulae, a bronze mirror and a washing set (vase and jug). This grave presents numerous analogies with similar ones found in southern Nervia and more specifically in Bavay. This grave can be dated to the second half of the IInd century.

A High-Pressure Raman Study of Mixed Perovskites BaCexZr1−xO3 (0≤x≤1)

“…Just after the transition PnmaPImma, the E intensity increases at the expense of the E intensity (13). These di!erent evolutions are also observed in the mixed compounds spectra for x"0.8 (Fig.…”

“…This splitting is also observed for BaCeO with decreasing temperature. BaCeO displays two bands (B and B ) at room temperature, and, when the ImmaPR3 c transition takes place, the B and B bands merge into a single band B (13). Hence by comparison with BaCeO , we can assume that the splitting of the B band in mixed compounds indicates that the transition R3 cPImma takes place as pressure increases.…”

“…2}4) which increase in intensity, shows that the phase transition concerns the whole sample. Based on results obtained on pure BaCeO (12,13,16), transitions toward phases of lower symmetry can be expected. The use of a high-pressure cell makes it di$cult to investigate the Raman spectra below 100 cm\.…”

“…This is the so-called quasiharmonic approximation which assumes that P (and ¹) a!ects the frequencies only through a volume variation. Di!erent relationships between force constants k and bond lengths d have been proposed for ionic materials (13,15). Assuming that force constants vary as d\L where n is a parameter and introducing the harmonic oscillator relationship, one obtains…”

“…1). These space group determinations, based on the symmetry properties of Raman transitions and on correlations with the well-known temperature phase transition of BaCeO (12,13), were later con"rmed by neutron di!raction (14). One of the interesting results of this previous study was the observation of a Raman spectrum for BaZrO (theoretically forbidden by symmetry), which was interpreted as mainly made of "rstorder bands and of some second-order Raman bands.…”