Low Temperature Electron Microscopy with High Field Superconducting Lenses

Cryo-electron microscope with high field superconducting lense

Integrated Research and Training in Space-molecular Biology Semiannual Progress Report, Apr. 1 - Sep. 30, 1966

Development and maintenance of electron microscope with high-field superconducting solenoid lense

Exobiology study - Analytical systems for biological study of Mars. The role of electron microscopy and electron optical techniques in exobiology

Electron microscopy and optical techniques for biological Mars studie

Electron Microscopy with Superconducting Lenses

Electron microscopy with superconducting lense

Investigations in space-related molecular biology, including considerations of the molecular organization of extraterrestrial matter Technical progress report

Space related molecular biology and molecular organization of extraterrestrial matter - design and construction of high vacuum container for transfer of extraterrestrial collecting surface

High voltage electron microscopy of lunar samples

Lunar pyroxenes from Apollo 11, 12, 14, and 15 were investigated. The iron-rich and magnesium-rich pyroxene specimens were crushed to a grain size of ca. 50 microns and studied by a combination of X-ray and electron diffraction, electron microscopy, 57 Fe Mossbauer spectroscopy and X-ray crystallography techniques. Highly ordered, uniform electron-dense bands, corresponding to exsolution lamellae, with average widths of ca. 230A to 1000A dependent on the source specimen were observed. These were?qr separated by wider, less-dense interband spacings with average widths of ca. 330A to 3100A. In heating experiments, splitting of the dense bands into finer structures, leading finally to obliteration of the exsolution lamellae was recorded. The extensive exsolution is evidence for significantly slower cooling rates, or possibly annealing, at temperatures in the subsolidus range, adding evidence that annealing of rock from the surface of the moon took place at ca. 600 C. Correlation of the band structure with magnetic ordering at low temperatures and iron clustering within the bands was studied

Normal modes of carbon nanotubes: similarities and differences with their continuum counterpart

Carbon nanotubes (CNTs) possess a range of unusually interesting and useful physicochemical properties. In this paper, the mechanical properties of single wall CNTs are investigated via free vibration normal modes using molecular mechanics models. The forcefield used is empirical and the usual assumptions of potential energy contributions coming from bondstretching, bond angle bending, and bond twisting for two, three, and four atom interactions respectively, are made. The validity of continuum behaviour is examined by comparing the modal spacing obtained from the molecular mechanics models and that obtained from classical continuum elastodynamics. The breakdown of continuum behaviour is systematically characterised for various combinations of length to diameter ratio as well as for the number of atoms per circumference