REPORTS Subnanometer Motion of Cargoes Driven by Thermal Gradients Along Carbon Nanotubes: related news

[REPORTS] Subnanometer Motion of Cargoes Driven by Thermal Gradients Along Carbon Nanotubes

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Comparing apples with oranges - the problem of nanotubes risk assessment

(Nanowerk Spotlight) Despite their name, carbon nanotubes (CNTs) are not made of 100% carbon. Depending on which of the various synthesis techniques is used in their production, CNTs have variable chemistries and physical properties resulting from their different metal catalysts or amorphous carbon coatings. As a result, they may contain large percentages of metal and carbonaceous impurities which will have different environmental and toxicological impacts. In early toxicological studies, researchers obtained confounding results - in some studies nanotubes were toxic; in others, they were not. The apparent contradictions were actually a result of the materials that the researchers were using, not appreciating that 'carbon nanotubes' are really 'carbon nanotubes + metal + amorphous impurities'.

Coupling of spin and orbital motion of electrons in carbon nanotubes

Electrons in atoms possess both spin and orbital degrees of freedom. In non-relativistic quantum mechanics, these are independent, resulting in large degeneracies in atomic spectra. However, relativistic effects couple the spin and orbital motion, leading to the well-known fine structure in their spectra. The electronic states in defect-free carbon nanotubes are widely believed to be four-fold degenerate1, 2, 3, 4, 5, 6, 7, 8, 9, 10, owing to independent spin and orbital symmetries, and also to possess electron-hole symmetry11. Here we report measurements demonstrating that in clean nanotubes the spin and orbital motion of electrons are coupled, thereby breaking all of these symmetries. This spin-orbit coupling is directly observed as a splitting of the four-fold degeneracy of a single electron in ultra-clean quantum dots.

3D Parts Integrated on Carbon-nanotube Wafer

National Institute of Advanced Industrial Science and Technology (AIST) manufactured integrated 3D carbon-nanotube components by using single-layer carbon nanotubes. A "carbon-nanotube wafer" developed by densely aligning carbon nanotubes enabled to use microfabrication techniques of lithography.

Coupling of spin and orbital motion of electrons in carbon nanotubes

Electrons in atoms possess both spin and orbital degrees of freedom. In non-relativistic quantum mechanics, these are independent, resulting in large degeneracies in atomic spectra. However, relativistic effects couple the spin and orbital motion, leading to the well-known fine structure in their spectra. The electronic states in defect-free carbon nanotubes are widely believed to be four-fold degenerate1, 2, 3, 4, 5, 6, 7, 8, 9, 10, owing to independent spin and orbital symmetries, and also to possess electron-hole symmetry11. Here we report measurements demonstrating that in clean nanotubes the spin and orbital motion of electrons are coupled, thereby breaking all of these symmetries. This spin-orbit coupling is directly observed as a splitting of the four-fold degeneracy of a single electron in ultra-clean quantum dots.

Spin Control: New Technique Sorts Nanotubes by Length

In a schematic of NISTs length separation technique for carbon nanotubes (l.) the nanotubes start at the bottom of a dense fluid. When spun in a centrifuge the nanotubes begin to migrate through the fluid driven by their buoyancy but the longer ones ...

Spin Control: New Technique Sorts Nanotubes by Length

In a schematic of NIST's length separation technique for carbon nanotubes (l.), the nanotubes start at the bottom of a dense fluid. When spun in a centrifuge, the nanotubes begin to migrate through the fluid driven by their buoyancy, but the longer ones move faster, spreading them out by length. Photos (r.) shows a typical sample at the start and after 94 hours of spinning at 1257 radians per second (roughly 12,000 RPM). Credit: NIST

Spin control: New technique sorts nanotubes by length

(Nanowerk News) Researchers at the National Institute of Standards and Technology (NIST) have reported* a new technique to sort batches of carbon nanotubes by length using high-speed centrifuges. Many potential applications for carbon nanotubes depend on the lengths of these microscopic cylinders, and one of the most important features of the new technique, say the scientists, is that it should be easily scalable to produce industrial quantities of high-quality nanotubes.

Texas, California Inventors Develop Single-Wall Carbon Nanotube Making Method

ALEXANDRIA, Va., March 21 -- Richard E. Smalley, Daniel T. Colbert, Andrew G. Rinzler, Pavel Nikolaev and Andreas Thess, all from Houston, and Ting Guo of San Diego, have developed a carbon nanotube making method.According to the U.S. Patent & Trademark Office: "This invention provides a method of making single-wall carbon nanotubes by laser vaporizing a mixture of carbon and one or more Group VIII transition metals. Single-wall carbon nanotubes preferentially form in the vapor and the one or more Group VIII transition metals catalyzed growth of the single-wall carbon nanotubes."

Carbon nanotubes for new thermoplastic...

Bayer MaterialScience has cooperated with Clariant Masterbatches on carbon nanotubes for new thermoplastics that impart excellent electrical conductivity and mechanical strength. Bayer MaterialScience will supply Clariant with industrial quantities of high-quality Baytubes carbon nanotubes for the manufacture of development and sales products for compounds and master batches. The carbon nanotubes (CNT), will initially be used in the new CESA® conductive CNT product range. Potential applications for the resultant compounds include electrically conductive machine components and packaging for delicate electronic components such as computer chips.

Carbon nanotubes for new thermoplastics

Bayer MaterialScience has cooperated with Clariant Masterbatches on carbon nanotubes for new thermoplastics that impart excellent electrical conductivity and mechanical strength. Bayer MaterialScience will supply Clariant with industrial quantities of high-quality Baytubes carbon nanotubes for the manufacture of development and sales products for compounds and master batches. The carbon nanotubes (CNT), will initially be used in the new CESA® conductive CNT product range. Potential applications for the resultant compounds include electrically conductive machine components and packaging for delicate electronic components such as computer chips.

Unidym Inc. Announces the First Flight of an Aircraft Using Carbon Nanotubes for Increased Fuselage Strength

Unidym, Inc., a majority-owned subsidiary of Arrowhead Research Corporation (NASDAQ:ARWR), announced today the first flight of an aircraft incorporating Unidym's carbon nanotubes into its airframe for increased strength and flexibility to combat the effects of aerodynamic stress and engine vibration. On April 11th Avalon Aviation's Giles G-200 aircraft flew with Unidym's carbon nanotubes incorporated into its carbon fiber composite engine cowling. The Giles G-200 is a high performance, single engine fully aerobatic carbon composite aircraft.

Nanotubes form sensitive sensors

carbon nanotubes, ultra microelectrodes Researchers in the University of Warwick’s Department of Chemistry have found a way of producing carbon nanotubes such that they instantly form a highly sensitive ready made electric circuit.

Carbon nanotube cluster successfully grown

A team of US scientists at Duke University [profile] in the USA say they have brought the commercial utilisation of carbon nanotubes in ICs a step further by using IC-like masking processes to align arrays of nanotubes. "To the best of our knowledge, it is the highest density of aligned, single-wall nanotubes reported," the researchers, led by Professor Jie Liu, wrote in the Journal of the American Chemical Society. Ten nanotubes, a few atoms thick and all facing in the same direction with none of them crossing, were grown in a micron-wide space. "Compared with what other people have done, we have reached a higher density of nanotubes," said Liu. The problem with nanotubes, up to now, has been getting them to grow straight, long enough and sufficiently densely packed to be practical for carrying current.

Carbon Nanotubes: Study data from Hunan University update knowledge of carbon nanotubes

(NewsRx.com) -- "Hybrid composites are of special scientific interest for biochemical applications wherein the abilities to modulate the morphology and property of the hybrid material are important. In this paper, the formation of poly-L-lysine/hydroxyapatite/carbon nanotube (PLL/HA/CNT) hybrid nanoparticles is described and a general design strategy for an immunosensing platform has been proposed on the basis of PLL/HA/CNT nanocomposite adsorption of antibodies," scientists in Changsha, People's Republic of China report.

Spin control: New technique sorts nanotubes by length

In a schematic of NIST's length separation technique for carbon nanotubes (l.), the nanotubes start at the bottom of a dense fluid. When spun in a centrifuge, the nanotubes begin...

Spin control: New technique sorts nanotubes by length

In a schematic of NIST's length separation technique for carbon nanotubes (l.), the nanotubes start at the bottom of a dense fluid. When spun in a centrifuge, the nanotubes begin...

Book Review of Chemistry and Physics of Carbon, Vol. 30

This book covers a wide range of topics on the chemistry, physics, and applications of carbon and carbon materials. Like previous volumes, the subjects discussed here reveal the multidisciplinary nature of carbon research, as can be seen in the titles of its chapters: (1) “Carbon Activation by Alkaline Hydroxides: Preparation and Reactions, Porosity and Performance: by Linares-Solano et al.; “Template Approaches to Preparing Porous Carbon� by Zhao and co-workers; “Characterization of Carbon Surface Chemistry� by Burg and Cagniant; and “Sorption of Heavy Oils into Carbon Materials� by Inagaki and co-workers. In addition to a standard Table of Contents, there is also a list of the contents of the previous 29 volumes as well as a subject index.

Bayer Carbon Nanotubes For New Thermoplastic Materials

(Nanowerk News) The excellent electrical conductivity and mechanical strength of Baytubes® carbon nanotubes were the decisive factors leading to a cooperation agreement on thermoplastics between Bayer MaterialScience AG and Clariant Masterbatches (Deutschland) GmbH. Bayer MaterialScience will supply Clariant with industrial quantities of high-quality Baytubes® for the manufacture of development and sales products for compounds and master batches. The carbon nanotubes, CNT for short, will initially be used in the new CESA® conductive CNT product range. Potential applications for the resultant compounds include electrically conductive machine components and packaging for delicate electronic components such as computer chips.

Nanochemistry inside carbon nanotubes

(Nanowerk Spotlight) As far as test tubes go, it doesn't get any smaller than a single-walled carbon nanotube (SWCNT). Among the wide range of interesting properties exhibited by SWCNTs is their capacity to encapsulate molecules within their quasi one-dimensional cavity. The confinement offered by the nanotube could serve as a nanoscale test tube to constrain a chemical reaction. This was demonstrated in principle back in 1998, when the coalescence of adjacent fullerenes was observed by transmission electron microscopy ("Encapsulated C60 in carbon nanotubes"). In the following years, scientists have extensively experimented with filling nanotubes with other fullerenes, atoms, molecules and, very recently, with organic molecules. Owing to their large variety with diverse chemical properties, the incorporated organic molecules can tune the

New device uses carbon nanotubes to rate chillis' hotness

Scientists have developed a new device that takes the help of carbon nanotubes to provide an objective and cost effective way to rate how hot a particular chilli is.

New device uses carbon nanotubes to rate chillis' hotness

London, May 13 : Scientists have developed a new device that takes the help of carbon nanotubes to provide an objective and cost effective way to rate how hot a particular chilli is.

Growth of High-Density Parallel Arrays of Long Single-Walled Carbon Nanotubes on Quartz Substrates

Herein we report a CVD approach to prepare high-density and perfectly aligned arrays of long SWNTs on stable temperature (ST)-cut quartz substrates using copper as catalyst and ethanol as carbon source. Compared with earlier reports, we have demonstrated that the aligned nanotube arrays can be grown on ST quartz substrate without the need of thermal annealing. The density can reach >50 nanotubes per micron and the length can be a few millimeters. Additionally, we have obtained direct proof on the “tip-growth� mechanism for the aligned nanotubes and important evidence that explained the termination of the growth.

Unidym Inc. Spins off Ensysce Biosciences Inc. to Pursue Medical Therapeutic Applications of Carbon Nanotubes

Unidym, Inc., a majority-owned subsidiary of Arrowhead Research Corporation (NASDAQ:ARWR), announced today the formation of a spin-off company, Ensysce Biosciences Inc., that will focus on research into the medical therapeutic applications of carbon nanotubes. Unidym has licensed its extensive nanotechnology patent portfolio to Ensysce for this field of use and in return holds a significant equity position in Ensysce. The inception of Ensysce stems from the final research interests of the late Dr. Richard Smalley, the 1996 Nobel Laureate for Chemistry from Rice University, who was among the pioneers in considering the potential therapeutic applications for carbon nanotubes. Unidym acquired rights to Dr. Smalley's work in carbon nanotechnology through a corporate merger in April of last year.

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