نتایج جستجو برای: walled tube
تعداد نتایج: 110019 فیلتر نتایج به سال:
A new kind of carbon foam, which is based on the welding of single-walled carbon nanotubes, is built in a computer simulation. Its precisely defined architecture and all atomic positions allow one to perform detailed theoretical analysis of the properties. Such foam is as light as 19 of steel, while its stiffness is similar and nearly isotropic, and it represents a strong three-dimensional mate...
Atomic force microscopy tips are used to apply point-like local gates to manipulate the electrical properties of individual single-walled carbon nanotubes ~SWNT! contacted by Ti electrodes. Depleting a semiconducting SWNT at a local point along its length leads to orders of magnitude decrease of the nanotube conductance, whereas local gating to metallic SWNTs causes no change in the conductance...
A 12-year-old Chinese girl was demonstrated multivessel distortion and malformation: aortic coarctation with the narrowest lumen diameter measuring of 4 mm located between the left common carotid artery and the left subclavian artery, a huge and thin-walled aneurysm is connected to the coarctation, and the descending aorta was distorted. Cerebrovascular revealed distorted arteries and a complet...
Aqueous suspensions of length selected single-walled carbon nanotubes were studied by atomic force microscopy (AFM) in order to probe the influence of sonication on nanotube scission. The maximum of the tube length distribution, lM, initially exhibits a power law dependence on the sonication time, t - roughly as lM approximately t(-0.5). This and the limiting behavior observed at longer times c...
Antiferromagnetic manipulation was used to controllably stretch individual metallic single-walled carbon nanotubes ~SWNT’s!. We have found that SWNT’s can sustain elongations as great as 30% without breaking. Scanned gate microscopy and transport measurements were used to probe the effects of the mechanical strain on the SWNT electronic properties, which revealed a strain-induced increase in in...
We show that catalyst pre-treatment conditions can have a profound effect on the chiral distribution in single-walled carbon nanotubes chemical vapor deposition. Using a SiO2-supported Cobalt model catalyst and pre-treatment in NH3, we obtain a comparably narrowed chiral distribution with a downshifted tube diameter range, independent of the hydrocarbon source. Our findings demonstrate that the...
Modulation doping of a semiconducting single-walled carbon nanotube along its length leads to an intramolecular wire electronic device. The nanotube is doped n-type for half of its length and p-type for the other half. Electrostatic gating can tune the system into p-n junctions, causing it to exhibit rectifying characteristics or negative differential conductance. The system can also be tuned i...
The (n,m) spectral features for isolated metallic single walled carbon nanotubes were deduced by examining Raman excitation profiles. Correlation of the radial breathing mode frequency with diameter identifies the (n,m) index of the metallic tube. Observation of the energy of Raman intensity maximum provides experimental values for the optical transitions directly, and allows for model independ...
The crush behaviors of steel tubes filled with nanoporous-materials-functionalized liquids are experimentally investigated under quasi-static and dynamic conditions. Results show that the nanoporous-materials-functionalized liquid can enhance the load-carrying and the energy absorption capacities of thin-walled tubes, as the buckling mode is affected. The effective buckling stress increases wit...
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