710 research outputs found
Growth of carbon nanotubes on quasicrystalline alloys
We report on the synthesis of carbon nanotubes on quasicrystalline alloys.
Aligned multiwalled carbon nanotubes (MWNTs) on the conducting faces of
decagonal quasicrystals were synthesized using floating catalyst chemical vapor
deposition. The alignment of the nanotubes was found perpendicular to the
decagonal faces of the quasicrystals. A comparison between the growth and tube
quality has also been made between tubes grown on various quasicrystalline and
SiO2 substrates. While a significant MWNT growth was observed on decagonal
quasicrystalline substrate, there was no significant growth observed on
icosahedral quasicrystalline substrate. Raman spectroscopy and high resolution
transmission electron microscopy (HRTEM) results show high crystalline nature
of the nanotubes. Presence of continuous iron filled core in the nanotubes
grown on these substrates was also observed, which is typically not seen in
MWNTs grown using similar process on silicon and/or silicon dioxide substrates.
The study has important implications for understanding the growth mechanism of
MWNTs on conducting substrates which have potential applications as heat sinks
Intrinsic Decoherence in Mesoscopic Systems
We present measurements of the phase coherence time in six
quasi-1D Au wires and clearly show that is temperature independent
at low temperatures. We suggest that zero-point fluctuations of the intrinsic
electromagnetic environment are responsible for the observed saturation of
. We introduce a new functional form for the temperature dependence
and present the results of a calculation for the saturation value of
. This explains the observed temperature dependence of our samples
as well as many 1D and 2D systems reported to date.Comment: 4 pages, 4 figures & 1 tabl
Isolated Hepatic Tuberculosis: an uncommon presentation of a common entity.
Hepatic tuberculosis is commonly encountered in patients with widespread miliary disease. Isolated affection of the liver is extremely rare. We present a case of a young woman who presented with a subacute afebrile hepatic failure. Investigations including a liver biopsy proved that the presentation was due to granulomatous hepatitis secondary to mycobacterial infection of the liver. It is important that tuberculosis be kept in mind especially in endemic areas even in atypical clinical scenarios by clinicians, radiologists, and pathologists. Use of anti-tuberculous drugs in such cases is usually successful and must be instituted early
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