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Nanotechnology Spotlight

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Showing Spotlights 353 - 360 of 386 in category Fabrication Technologies and Devices (newest first):

 

The challenge of separating and sorting carbon nanotubes after production

Current production methods for carbon nanotubes result in units with different diameter, length, chirality and electronic properties, all packed together in bundles, and often blended with some amount of amorphous carbon. The separation of nanotubes according to desired properties remains a technical challenge. Especially single-walled carbon nanotube (SWCNT) sorting is a challenge because the composition and chemical properties of SWCNTs of different types are very similar, making conventional separation techniques inefficient.

Posted: Aug 21st, 2006

A green synthesis technique for fabricating carbon-coated magnetic nanoparticles

Encapsulating metal nanoparticles inside carbon shells is of considerable significance but fraught with high manufacturing cost due to high energy consumption and intensive use of hardware. This cost issue limits their practical applications. Researchers in China have developed a novel, simple, efficient, and economical synthesis technique for the fabrication of carbon-encapsulated nanostructures where the carbonization is conducted at a relatively low temperature of 160C in water and no toxic reagents are added. This new technique is facile and versatile, and suitable for the coating of other transition metal with carbon.

Posted: Aug 15th, 2006

The effects of contamination during nanoparticle production

A new study by Swedish researchers shows that gold nano spheres with a diameter of 7 nm, produced in a conventional laboratory surrounding, activate human antigen presenting dendritic cells (DCs) to induce proliferation of peripheral blood mononuclear cells (PBMC), mixed with either allergenic or autologous DCs. This effect was found to be due to endotoxin (lipopolysaccharide, LPS) contamination of the nanoparticles. When particles were produced in a controlled way eliminating endotoxin contamination, the activation of the DCs did not take place.

Posted: Aug 14th, 2006

Towards multidimensional, multicomponent, and multifunctional nanomaterials

With the recent development in nanoscience and nanotechnology, a large variety of single-component nanomaterials (such as carbon nanotubes, nanoparticles, and quantum dots) and devices have been reported. There is now a pressing need to integrate multicomponent nanoscale entities into multifunctional systems and to connect these nano-systems to the micro/macro-world. This connection from the nano world to the macro world has been one of the long-standing problems in nanotechnology and still remains a big challenge. A novel approach of growing aligned carbon nanotubes (CNTs) around microsized carbon fibers should provide a useful platform technology for the development of various multidimensional and multifunctional nanomaterials and devices.

Posted: Aug 11th, 2006

Triangular cross-sectional silica fibers: a novel growth phenomenon for amorphous materials

Researchers in Japan have synthesized novel silica fibers. Unlike any previously reported one-dimensional silica nano- and microstructures, the novel fibers display a triangular cross-section, which is not typical for amorphous materials. These prism-like silica fibers open up a new morphological type of silicon-based materials which may have highly promising potentials. They may be of significant interest for optoelectronic applications and the improvement of SnO2 chemical sensors and catalysts.

Posted: Aug 2nd, 2006

Self-assembly of nanoparticles - a step towards realizing completely self-organized devices

The fabrication of ultrafine structures beyond the limits of conventional lithography is a topic of tremendous importance and is expected to play a significant role in the realization of futuristic nanotechnology. It is also equally important to develop functional material systems of ultrafine dimensions in order to achieve this goal. An important step towards realization of nanodevices is self-organized nanopatterning of functional structures. A new technique, which might be called chemical lithography, enables the regular assembly of optically active nanoparticles on a silicon surface.

Posted: Aug 1st, 2006

Nanocomposites from silica and spider silk

Researchers combined two different materials from nature, both of which have unique and important properties, into one material system via genetic engineering. By combining the features of silk with biosilica through the design, synthesis, and characterization of a novel family of chimeric proteins an innovative biomimetic nanocomposite was fabricated.

Posted: Jul 27th, 2006

A new concept for compound nanotube fabrication

A new method based on the nanoscale Kirkendall effect was demonstrated to fabricate compound nanotubes. Through a spinel-forming solid-state reaction, high aspect-ratio core-shell ZnO-Al2O3 nanowires transform into monocrystalline ZnAl2O4 nanotubes.

Posted: Jul 14th, 2006