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- Mechanical and electronic properties of vanadium oxide nanotubes
Posted by Jin Won Seo
B. Sipos, M. Duchamp, A. Magrez, L. Forró, N. Barišić, A. Kis, J. W. Seo, F. Bieri, F. Krumeich, R. Nesper, and G. R. Patzke
Vanadium oxide nanotubes with a diameter of 20–100 nm and an aspect ratio of 50–100 were synthesized by hydrothermal method. Young’s modulus of 20–80 GPa was obtained by bending measurements of individual nanotubes using an atomic force microscope. Electrical resistivity and thermopower measurements on a large assembly of nanotubes determined the characteristic energies required to put a charge into a polaronic site (∆Eg=0.20 eV) and to extract and propagate the polaron between neighboring sites (∆Ep=0.09 eV).
- The use of liquid crystals as electrorheological fluids in microsystems: model and measurements
Posted by Dominiek Reynaerts
M. De Volder, K. Yoshida, S. Yokota and D. Reynaerts
Fluids with controllable flow properties have gained considerable interest in the past few years. Some of these fluids such as magnetorheologic fluids are now widely applied to active dampers and valves. Although these fluids show promising properties for microsystems, their applicability is limited to the microscale since particles suspended in these fluids tend to obstruct microchannels. This paper investigates the applicability of electrorheologic liquid crystals (LCs) in microsystems. Since LCs do not contain suspended particles, they show intrinsic advantages over classic rheologic fluids in micro-applications. This paper presents a novel physical model that describes the static and the dynamic behaviour of electrorheologic LCs. The developed model is validated by comparing simulations and measurements performed on a rectangular microchannel. This assessment shows that the model presented in this paper is able to simulate both static and dynamic properties accurately. Therefore, this model is useful for the understanding, simulation and optimization of devices using LCs as electrorheological fluid. In addition, measurements performed in this paper reveal remarkable properties of LCs, such as high bandwidths and high changes in flow resistance.
- A fast, high stiffness and high-resolution piezoelectric motor with integrated bearing and driving functionality
Posted by Dominiek Reynaerts
H. Van Brussel, W. Van de Vijver, M. De Volder, S. Devos and D. Reynaerts
With growing requirements on the precision of production machines, as expressed by the Taniguchi curves, the need arises for novel actuators that are able to combine high stiffness and high position resolution with high drive speeds. In this paper two novel integrated linear actuation systems with high active stiffness and with the unique ability to provide simultaneously high-resolution slow motion and lower-resolution high-speed motion, based on piezotechnology, are presented.
Potential applications are stages for novel high-precision abrasive machining (e.g. ultraprecision grinding), lithography (e.g. extreme-UV wafer steppers), positioning devices working in vacuum (e.g. scanning electron microscopy).
- A PDMS lipseal for hydraulic and pneumatic microactuators
Posted by Dominiek Reynaerts
M. De Volder, F. Ceyssens, D. Reynaerts and R. Puers
Recent publications show that hydraulic and pneumatic microactuators offer superior power and force densities at the microscale. The main technological barrier for the development of these actuators is the lack of microseal technologies. These seals must prevent the driving ﬂuid leaking to the outside world without introducing friction. This paper presents a method to fabricate miniature lipseals in batch quantities. A simulation method for the design of these seals is developed and validated experimentally. Hydraulic and pneumatic actuators comprising lipseals have been fabricated and tested. These prototype actuators have an outside diameter of 1.5 mm, and were able to generate forces of 1.2 N at a supply pressure of 1.6 MPa.
External news feeds
- Single-cell transfection tool enables added control for biological studies
(Phys.org) â€”Northwestern University researchers have developed a new method for delivering molecules into single, targeted cells through temporary holes in the cell surface. The technique could find applications in drug delivery, cell therapy, and related biological fields.
- Radioactive nanoparticles target cancer cells
Cancers of all types become most deadly when they metastasize and spread tumors throughout the body. Once cancer has reached this stage, it becomes very difficult for doctors to locate and treat the numerous tumors that can develop. Now, researchers at the University of Missouri have found a way to create radioactive nanoparticles that target lymphoma tumor cells wherever they may be in the body. Michael Lewis, an associate professor of oncology in the MU College of Veterinary Medicine, says being able to target secondary tumors is vital to successfully treating patients with progressive cancers.
- Scientists uncover how grapefruits provide a secret weapon in medical drug delivery
(Phys.org) â€”Grapefruits have long been known for their health benefits, and the subtropical fruit may revolutionize how medical therapies like anti-cancer drugs are delivered to specific tumor cells. University of Louisville researchers have uncovered how to create nanoparticles using natural lipids derived from grapefruit, and have discovered how to use them as drug delivery vehicles. UofL scientists Huang-Ge Zhang, D.V.M., Ph.D., Qilong Wang, Ph.D., and their team today (May 21, 2013), published their findings in Nature Communications.
- Tailoring optical processors: Arranging nanoparticles in geometric patterns allows for control of light with light
Rice University scientists have unveiled a robust new method for arranging metal nanoparticles in geometric patterns that can act as optical processors that transform incoming light signals into output of a different color. The breakthrough by a team of theoretical and applied physicists and engineers at Rice's Laboratory for Nanophotonics (LANP) is described this week in the Proceedings of the National Academy of Sciences.
- How gold nanoparticles can help fight ovarian cancer
Positively charged gold nanoparticles are usually toxic to cells, but cancer cells somehow manage to avoid nanoparticle toxicity. Mayo Clinic researchers found out why, and determined how to make the nanoparticles effective against ovarian cancer cells. The discovery is detailed in the current online issue of the Journal of Biological Chemistry.
- Researchers perform fastest measurements ever made of ion channel proteins
The miniaturization of electronics continues to create unprecedented capabilities in computer and communications applications, enabling handheld wireless devices with tremendous computing performance operating on battery power. This same miniaturization of electronic systems is also creating new opportunities in biotechnology and biophysics.
- Researchers develop method to inkjet print highly conductive, bendable layers of graphene
(Phys.org) â€”Imagine a bendable tablet computer or an electronic newspaper that could fold to fit in a pocket.
- Advance in nanotech gene sequencing technique
(Phys.org) â€”The allure of personalized medicine has made new, more efficient ways of sequencing genes a top research priority. One promising technique involves reading DNA bases using changes in electrical current as they are threaded through a nanoscopic hole.
- Faster, stronger, lighter: New technique advances carbon-fiber composites
These days, aerospace engineering is all about the light stuff: building airplanes with lighter wings, fuselage and landing gear in an effort to reduce fuel costs.
- Engineers' nanoantennas improve infrared sensing
(Phys.org) â€”A team of University of Pennsylvania engineers has used a pattern of nanoantennas to develop a new way of turning infrared light into mechanical action, opening the door to more sensitive infrared cameras and more compact chemical-analysis techniques.
- Kinks and curves at the nanoscale
One of the basic principles of nanotechnology is that when you make things extremely smallâ€”one nanometer is about five atoms wide, 100,000 times smaller than the diameter of a human hairâ€”they are going to become more perfect.
- How nanotechnology could keep your heart healthy
Since the heart is such a delicate and critical organ, clinicians usually opt not to intervene with the dead cells that remain after a heart attack or cardiac disease. "But we think that all heart attacks deserve some kind of treatment because it puts so much stress on the rest of the heart," said Thomas Webster, professor and chair of the Department of Chemical Engineering. Even a square centimeter of dead heart tissue can put significant strain on the rest of the heart, which has to pick up the slack, he said.
- Research improves dry lubricant used in machinery and biomedical devices
Nearly everyone is familiar with the polytetrafluoroethylene (PTFE), otherwise known as Teflon, the brand name used by the chemical company DuPont. Famous for being "non-sticky" and water repellent, PTFE is a dry lubricant used on machine components everywhere, from kitchen tools and engine cylinders to space and biomedical applications.
- Stacking 2-D materials produces surprising results
(Phys.org) â€”Graphene has dazzled scientists, ever since its discovery more than a decade ago, with its unequalled electronic properties, its strength and its light weight. But one long-sought goal has proved elusive: how to engineer into graphene a property called a band gap, which would be necessary to use the material to make transistors and other electronic devices.
- Graphene-boron mix shows promise for lithium-ion batteries
Frustration led to revelation when Rice University scientists determined how graphene might be made useful for high-capacity batteries.
- Researchers report first fully integrated artificial photosynthesis nanosystem
(Phys.org) â€”In the wake of the sobering news that atmospheric carbon dioxide is now at its highest level in at least three million years, an important advance in the race to develop carbon-neutral renewable energy sources has been achieved. Scientists with the U.S. Department of Energy (DOE)'s Lawrence Berkeley National Laboratory (Berkeley Lab) have reported the first fully integrated nanosystem for artificial photosynthesis. While "artificial leaf" is the popular term for such a system, the key to this success was an "artificial forest."
- DNA-guided assembly yields novel ribbon-like nanostructures
(Phys.org) â€”Scientists at the U.S. Department of Energy's Brookhaven National Laboratory have discovered that DNA "linker" strands coax nano-sized rods to line up in way unlike any other spontaneous arrangement of rod-shaped objects. The arrangement-with the rods forming "rungs" on ladder-like ribbons linked by multiple DNA strands-results from the collective interactions of the flexible DNA tethers and may be unique to the nanoscale. The research, described in a paper published online in ACS Nano, a journal of the American Chemical Society, could result in the fabrication of new nanostructured materials with desired properties.
- Snake's ultra-black spots may aid high-tech quest
Scientists have identified nanostructures in the ultra-black skin markings of an African viper which they said Thursday could inspire the quest to create the ultimate light-absorbing material.
- Carbon in a twirl: The science behind a self-assembled nano-carbon helix
Nanotechnology draws on the fabrication of nanostructures. Scientists have now succeeded in growing a unique carbon structure at the nanoscale that resembles a tiny twirled mustache. Their method might lead the way to the formation of more complex nano-networks. Researchers of the Electronic Properties of Materials Group at the Faculty of Physics (University of Vienna) and their international collaborators have published their results in the new open-access journal of the Nature Publishing group, Scientific Reports.
- Moth-inspired nanostructures take the color out of thin films
Inspired by the structure of moth eyes, researchers at North Carolina State University have developed nanostructures that limit reflection at the interfaces where two thin films meet, suppressing the "thin-film interference" phenomenon commonly observed in nature. This can potentially improve the efficiency of thin-film solar cells and other optoelectronic devices.
- Nanotechnology could help fight diabetes: Injectable nanogel can monitor blood-sugar levels, secrete insulin when needed
Injectable nanoparticles developed at MIT may someday eliminate the need for patients with Type 1 diabetes to constantly monitor their blood-sugar levels and inject themselves with insulin.
- Ultraresponsive magnetic nanoscavengers for next generation water purification
(Phys.org) â€”Among its many talents, silver is an antibiotic. Titanium dioxide is known to glom on to certain heavy metals and pollutants. Yet other materials do the same for salt. In recent years, environmental engineers have sought to disinfect, depollute, and desalinate contaminated water using nanoscale particles of these active materials. Engineers call them nanoscavengers. The hitch from a technical standpoint is that it is nearly impossible to reclaim the nanoscavengers once in the water.
- 40-year-old prediction confirmed: First direct proof of Hofstadter butterfly fractal observed in moire superlattices
A team of researchers from Columbia University, City University of New York, the University of Central Florida (UCF), and Tohoku University and the National Institute for Materials Science in Japan, have directly observed a rare quantum effect that produces a repeating butterfly-shaped energy spectrum, confirming the longstanding prediction of this quantum fractal energy structure, called Hofstadter's butterfly. The study, which focused on moirÃ©-patterned graphene, is published in the May 15, 2013, Advance Online Publication (AOP) of Nature.
- Catching graphene butterflies
Writing in Nature, a large international team led Dr Roman Gorbachev from The University of Manchester shows that, when graphene placed on top of insulating boron nitride, or 'white graphene', the electronic properties of graphene change dramatically revealing a pattern resembling a butterfly.
- Physicists discover a new kind of friction in the nanoworld
Whether in vehicle transmissions, hip replacements, or tiny sensors for triggering airbags: The respective components must slide against each other with minimum friction to prevent loss of energy and material wear. Investigating the friction behavior of nanosystems, scientists from the Technische Universitaet Muenchen have discovered a previously unknown type of friction that sheds new light on some previously unexplainable phenomena.
- Squishy hydrogels may be the ticket for studying biological effects of nanoparticles
(Phys.org) â€”A class of water-loving, jelly-like materials with uses ranges ranging from the mundane, such as superabsorbent diaper liners, to the sophisticated, such as soft contact lenses, could be tapped for a new line of serious work: testing the biological effects of nanoparticles now being eyed for a large variety of uses.
- Scientists discovering new uses for tiny carbon nanotubes
Nanotubes are stronger than steel and smaller than any element of silicon-based electronics. They can potentially process information faster while using less energy. The challenge has been figuring out how to incorporate these properties into useful electronic devices. Now scientists at the University of California, Riverside have discovered that by adding ionic liquidâ€”a kind of liquid saltâ€”they can modify the optical transparency of single-walled carbon nanotube films in a controlled pattern.
- Chemists demonstrate nanoscale alloys so bright they could have potential medical applications
(Phys.org) â€”Alloys like bronze and steel have been transformational for centuries, yielding top-of-the-line machines necessary for industry. As scientists move toward nanotechnology, however, the focus has shifted toward creating alloys at the nanometer scaleâ€”producing materials with properties unlike their predecessors.
- Microgravity experiment gets funding, may go to International Space Station
A microgravity experiment designed at The Methodist Hospital Research Institute will be funded by The Center for the Advancement of Science in Space (CASIS) to fly aboard the International Space Station U.S. National Laboratory.
- Researchers develop synthetic HDL cholesterol nanoparticles
(Phys.org) â€”Atherosclerosis, a buildup of cellular plaque in the arteries, remains one of the leading causes of death globally. While high-density lipoprotein, or HDL, the so-called good cholesterol, is transferred to the liver for processing, low-density lipoprotein, or LDL, builds up in the arteries in the form of plaque.