Observation of unusual mass transport in solid hcp (4)He.

Comment on "observation of unusual mass transport in solid hcp 4He".

Local modes, phonons, and mass transport in solid 4 he

Local modes, phonons, and mass transport in solid 4 He. Abstract We propose a model to treat the local motion of atoms in solid 4 He as a local mode. In this model, the solid is assumed to be described by the Self Consistent Harmonic approximation, combined with an array of local modes. We show that in the bcc phase the atomic local motion is highly directional and correlated, while in the hcp ...

Debye - Waller factor measurements of solid 3 He and 4

X-ray synchrotron radiation was used to measure Debye-Waller factors of helium crystals for both He and He in both hcp and fcc phases. To our knowledge, there are no previous measurements for He. The ranges studied for He and He crystals were 11.52–12.82 and 10.95–12.13 cm, respectively, and 11.5–18.2 and 12.0–20.3 K. With small uncertainty, only a Gaussian dependence upon momentum transfer Q w...

Off-diagonal long-range order in solid 4He.

Measurements of the moment of inertia by Kim and Chan have found that solid (4)He acts like a supersolid at low temperatures. To understand the order in solid 4(He), we have used path integral Monte Carlo simulations to calculate the off-diagonal long-range order (ODLRO) [equivalent to Bose-Einstein condensation (BEC)]. We do not find ODLRO in a defect-free hcp crystal of (4)He at the melting d...

Pituitary Chondrosarcoma presenting as a sellar and suprasellar mass with parasellar extension: An Unusual presentation

Chondrosarcoma is a mesenchymal tumor composed of tumor cells producing cartilage. It is more common in older age and often affects the axial skeleton. We report a rare case of chondrosarcoma mimicking a sellar and suprasellar mass with parasellar extension. A 40 yr woman presented with decreasing visual acuity and headache. Magnetic resonance (MR) image revealed a cystic sellar and suprasellar...