Physics & Mathematics

Silicon Nanospheres Rank Among Hardest Known Materials

University of Minnesota researchers have made the first-ever hardness measurements on individual silicon nanospheres and shown that the nanospheres’ hardness falls between the conventional hardness of sapphire and diamond, which are among the hardest known materials. Being able to measure such nanoparticle properties may eventually help scientists design low-cost superhard materials from these nanoscale building blocks. Up to four times harder than typical silicon — a principal ingredient of computer chips, glass and sand — the nanospheres demonstrate that other materials at the nanoscale, including sapphire, may also have vastly improved mechanical properties.

Nanotech Decoys for Viruses

Using nanotechnology to stop HIV viruses from entering cells is the ultimate aim of a new project at the University of California, Davis. The researchers hope to create tiny particles that can interfere with the proteins that viruses such as HIV use to attach to cells.

Researchers crack nature's method for creating crystals on a sphere

In a discovery that is likely to impact fields as diverse as medicine and nanomanufacture, researchers have determined how nature arranges charged particles in a thin layer around a sphere. The leap forward in understanding this theoretical problem may help reveal structural chinks in the outer armor of viruses and bacteria (revealing potential drug targets) and guide engineers designing new molecules. On a flat surface, particles that repel each other will arrange themselves to create a stable energy state, eventually settling at vertices within a lattice of identical triangles much like billiard balls at the start of a game.

Pulsar Bursts Coming From Beachball-Sized Structures

In a major breakthrough for understanding what one of them calls “the most exotic environment in the Universe,” a team of astronomers has discovered that powerful radio bursts in pulsars are generated by structures as small as a beach ball. “These are by far the smallest objects ever detected outside our solar system,” said Tim Hankins, leader of the research team, which studied the pulsar at the center of the Crab Nebula, more than 6,000 light-years from Earth. “The small size of these regions is inconsistent with all but one proposed theory for how the radio emission is generated,” he added.

European astronomers observe first evaporating planet

Using the Hubble Space Telescope, astronomers have, for the first time, observed the atmosphere of an extrasolar planet evaporating into space. Much of this planet may eventually disappear, leaving only a dense core. It is a type of extrasolar planet known as a ‘hot Jupiter’. These giant gaseous planets orbit their stars very closely, drawn to them like moths to a flame. The scorched planet called HD 209458b orbits ‘only’ 7 million kilometres from its yellow Sun-like star. By comparison, Jupiter, the closest gas giant in our Solar System, orbits 780 million kilometres from our Sun. NASA/ESA Hubble Space telescope observations reveal a hot and puffed-up evaporating hydrogen atmosphere surrounding the planet. This huge envelope of hydrogen resembles a comet with a tail trailing behind the planet. Earth also has an extended atmosphere of escaping hydrogen gas, but the loss rate is much lower.

Researchers Discover How to Make Ultra-Dense Nanowire Lattices

Researchers have invented a new technique for producing “Ultra High Density Nanowire Lattices and Circuits.” The method, for which a patent is pending, is akin to intaglio printmaking processes in which printing is done from ink below the surface of the plate. Intaglio processes emboss paper into the plate’s incised lines. The CNSI nanowires are like the embossed ink on a paper substrate, except that the nanowires are much, much smaller than ink lines. Take, for instance, a grid of crossed nanowires. Each cross represents the element of a simple circuit. The nanowire junction density reported in the “Science Express” article is in excess of 1011 per square centimeter.

Virtual observatory prototype produces surprise discovery

A new approach to finding undiscovered objects buried in immense astronomical databases has produced an early and unexpected payoff: a new instance of a hard-to-find type of star known as a brown dwarf. Scientists working to create the National Virtual Observatory (NVO), an online portal for astronomical research unifying dozens of large astronomical databases, confirmed discovery of the new brown dwarf recently. The star emerged from a computerized search of information on millions of astronomical objects in two separate astronomical databases. Thanks to an NVO prototype, that search, formerly an endeavor requiring weeks or months of human attention, took approximately two minutes.

Australian overturns 15 years of nano-science doctrine

An Australian mathematician has thrown 15 years of accepted scientific practice out the window by discovering a design flaw in a key component of the Atomic Force Microscope. His finding will force a rethink into the design and use of an instrument that has become a cornerstone of scientific measurement and analysis. Dr John Sader, at University of Melbourne’s Department of Mathematics and Statistics, and Particulate Fluids Processing Centre, used established mechanical principles to prove that the popular V-shaped cantilever inadvertently degrades the performance of the instrument, and delivers none of its intended benefits.

What's lost is found again: 'Virtually' rebuilding Native American monuments

For five years now, a University of Cincinnati team has been piecing together the fragments of three little-known, prehistoric Native American cultures that left behind immense earthworks that rival Stonehenge in their astronomical accuracy. Most of these sites ? an extant example being Serpent Mound in Adams County, Ohio ? survived close to two millennia before they were gouged out or cultivated in the 19th century or paved over for development in the 20th century. And that’s where the extensive, national team, led by architect John Hancock of the Center for the Reconstruction of Historic Sites at UC, comes in.

New method for producing carbon nanoscrolls, an alternative to nanotubes

Chemists report in the Feb. 28 issue of Science a room-temperature chemical method for producing a new form of carbon called carbon nanoscrolls. Nanoscrolls are closely related to the much touted carbon nanotubes — which may have numerous industrial applications — but have significant advantages over them, said Lisa Viculis and Julia Mack, the lead authors of the article and graduate students in the laboratory of Richard B. Kaner, UCLA professor of chemistry and biochemistry.

Researchers create highest resolution optical image ever

Researchers at the University of Rochester have created the highest resolution optical image ever, revealing structures as small as carbon nanotubes just a few billionths of an inch across. The new method should open the door to previously inaccessible chemical and structural information in samples as small as the proteins embedded in a cell’s membrane. The research appears in today’s issue of Physical Review Letters.

Nasa finds 'cocoon' inside the Black Widow's web

NASA’s Chandra X-ray Observatory image of the mysterious “Black Widow” pulsar reveals the first direct evidence of an elongated cocoon of high-energy particles. (A pulsar is a rotating neutron star producing powerful beams of radiation that sweep like a searchlight.) This discovery shows this billion-year-old rejuvenated pulsar is an extremely efficient generator of a high-speed flow of matter and antimatter particles.

Cray, gov't team on first split-personality supercomputer

With the delivery next month of the Cray X1 supercomputer, the Department of Energy’s Oak Ridge National Laboratory and Cray Inc. will take a big step toward investigating computer architectures for scientific discovery. The Cray X1 is the first U.S. computer to offer vector processing and massively parallel processing capabilities in a single architecture and will be used to solving scientific problems in climate, biology, nanoscale materials, fusion and astrophysics.