Abstracts » Zoology and wildlife conservation

Exceptionally high Young's modulus observed for individual carbon nanotubes

Article Abstract:

Bundles of carbon nanotubes in a core deposit prepared by the carbon arc technique have a Young's modulus of (3.7 plus or minus 0.2) X 10 to the 12th power Pa. This value is much higher than that of carbon fibers. The Young's modulus is determined by measuring thermal vibrations of the nanotubes using a transmission electron microscope. Microscopic images show that the blurring of the free ends of the nanotubes is due to vibrations which increase with an increase in temperature. The carbon nanotubes are potentially useful in lightweight composite materials due to their low density and high stiffness.

Research, Measurement, Stress analysis (Engineering), Constants, Physical, Constants (Physics), Carbon fibers

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Extraordinary optical transmission through sub-wavelength hole arrays

Article Abstract:

A study prepared and analyzed a variety of two-dimensional arrays of cylindrical cavities in metallic films. Constraints in manipulating light include the low transmittivity of apertures smaller than the wavelength of an incident photon. It was found that arrays of such holes exhibit unusual zero-order transmission spectra at wavelengths bigger than the array period. The experiments indicated that the coupling of light with plasmons on the surface of the periodically patterned metal film was the cause of the unusual optical properties.

Observations, Photons, Light, Speed, Speed of light

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Light in tiny holes

Article Abstract:

A study reveals that the presence of tiny holes in an opaque metal film with sizes smaller than the wavelength of incident light, directs to a wide variety of unexpected optical properties like strongly enhanced transmission of light through the holes and wavelength filtering. These intriguing effects are found to be due to the interaction of the light with electronic resonances in the surface of the metal film and adjusting the size and geometry of the holes could control them.

United Kingdom, Optical properties, Metallic films, Mechanical properties

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