Abstract: Computed tomography scanning systems and methods using a field emission x-ray source are disclosed. An exemplary micro-computed tomography scanner comprises a micro-focus field emission x-ray source, an x-ray detector, an object stage placed between the x-ray source and the detector, an electronic control system and a computer that control the x-ray radiation and detector data collection, and computer software that reconstructs the three dimension image of the object using a series of projection images collected from different projection angles. Exemplary methods obtain a computed tomography image of an object in oscillatory motion using the micro computed tomography scanner.

Abstract: A method for attaching nanostructure-containing material onto a sharp tip of an object includes forming a suspension of pre-formed nanostructure-containing material in a liquid medium. An electrode is immersed in the suspension. The sharp tip of the object is arranged to be in contact with the suspension. A voltage is applied to the immersed electrode and to the sharp tip. The nanostructure-containing material attaches to the sharp tip of the object.

Abstract: Methods and apparatus for independent control of electron emission current and x-ray energy in x-ray tubes are provided. The independent control can be accomplished by adjusting the distance between the cathode and anode. The independent control can also be accomplished by adjusting the temperature of the cathode. The independent control can also be accomplished by optical excitation of the cathode. The cathode can include field emissive materials such as carbon nanotubes.

Abstract: The invention provides improved devices containing adherent carbon nanotube films, in particular electron field emitter structures containing such films. Previously, attaining even moderate adherence of powdery or mat-like nanotubes to a substrate was difficult, because of the perfect fullerene structure of nanotubes, which tend to exhibit no dangling bonds or defect sites where chemical bonding to the substrate is able to occur. The invention overcomes these problems, and provides a strongly adherent nanotube film, by a variety of fabrication processes.

Abstract: A method for the self assembly of a macroscopic structure with a preformed nano object is provided. The method includes processing a nano object to a desired aspect ratio and chemical functionality and mixing the processed nano object with a solvent to form a suspension. Upon formation of the suspension, a substrate is inserted into the suspension. By either evaporation of the solvent, changing the pH value of the suspension, or changing the temperature of the suspension, the nano objects within the suspension deposit onto the substrate in an orientational order. In addiiton, a seed crystal may be used in place of the substrate thereby forming single-crystals and free-standing membranes of the nano-objects.

Abstract: A method for fabricating adherent, patterned carbon nanotube films is provided. According to the invention, a substrate is patterned with a carbide-forming material, a carbon-dissolving material, or a low melting point metal. Carbon nanotubes are then deposited onto the patterned substrate, but have relatively poor adhesion to either the substrate material or the patterned material. The substrate is then annealed, typically in vacuum, at a temperature dependent on the particular patterning material, e.g., a temperature at which carbide formation occurs, at which carbon dissolution occurs, or at which the low melting point metal melts. The annealing thereby provides an adherent nanotube film over the patterned areas, while the nanotubes deposited onto the non-patterned areas are easily removed, e.g., by blowing, rubbing, brushing and/or ultrasonication in a solvent such as methanol.