Both teams made diamonds with defects in their crystal structure#a single nitrogen atom next to a missing carbon atom, a few nanometres below the surface.
the water s oxygen atoms share some of their electrons with vacant electron orbitals on the aluminium atoms,
missing oxygen atoms#that allowed water to latch on. Cheung suggests that Varanasi's ceramics were particularly hydrophobic
it is based not on carbon but on a latticework of boron and nitrogen atoms. Computer simulations have indicated that a rare crystalline form of boron nitride would resist indentation even better than diamond
A nanotwin is a crystalline segment that mirrors the orientation of atoms on the other side of an interface (a so-called twin boundary) within a material.
which the atoms of nitrogen and boron form an onionlike structure of nested layers. Pressed into macroscopic pellets
The researchers, at the University of California, Berkeley, say that the pulse of the clock is determined solely by the mass of its beating heart, a caesium atom.
Current atomic clocks are based on the microwave signals emitted by electrons inside an atom as they move from one energy level to another.
But those internal atomic oscillations are determined by the interactions between the atom s electrons and its nucleus
and to Louis de Broglie's subsequent insight that moving electrons (and atoms) behave like waves.
and 3#1025 Hz for a caesium atom.##Nevertheless, using a combination of atom interferometry and ultra-precision laser techniques,
M#ller and his team have, in essence, found a way to count those Compton cycles.
#which is where atom interferometry comes in. The researchers used a cloud of around 1 million caesium atoms divided in two.
One half was given a series of 10 kicks, or tiny laser-photon impacts, which slow the Compton cycles by a precisely known amount.
when the manipulated half of the cloud of atoms is reunited with the unaltered half: the output signal of the interferometer is at a maximum
But what is more important, M#ller says is that the only physical parameter that appears in the expression for the clock frequency is the mass of the caesium atoms."
which in principle can be built with a single atom, M#ller says, could serve as the foundation for a new definition of the kilogram tied to a precise laser frequency.
Schneider and his colleagues reached such sub-absolute-zero temperatures with an ultracold quantum gas made up of potassium atoms.
they kept the individual atoms in a lattice arrangement. At positive temperatures, the atoms repel,
making the configuration stable. The team then quickly adjusted the magnetic fields, causing the atoms to attract rather than repel each other."
"This suddenly shifts the atoms from their most stable, lowest-energy state to the highest possible energy state,
before they can react, says Schneider.""It s like walking through a valley, then instantly finding yourself on the mountain peak.
and the atoms would collapse inwards. But the team also adjusted the trapping laser field to make it more energetically favourable for the atoms to stick in their positions.
This result, described today in Science1, marks the gas s transition from just above absolute zero to a few billionths of a Kelvin below absolute zero.
whereas clouds of atoms would normally be pulled downwards by gravity, if part of the cloud is at a negative absolute temperature,
some atoms will move upwards, apparently defying gravity4. Another peculiarity of the sub-absolute-zero gas is that it mimics'dark energy'
Schneider notes that the attractive atoms in the gas produced by the team also want to collapse inwards,
when the charged plasma cooled into neutral atoms, that those photons could fly freely. Today they make up the CMB,
and neutral atoms of hydrogen and helium were beginning to form from the seething mass of charged plasma.
The fish's neurons make a protein that fluoresces in response to fluctuations in the concentration of calcium ions,
Researchers have known long that a crucial step in the process is the flow of calcium ions into the synapse area,
The technique incorporates some nickel atoms into the diamond crystal structure, forming what is called an 3 defect center.
and neutrons and the other two form a separate meson bit like two atoms combining to form a molecule.
These oxygen ions then travel through the membrane to the positively charged anode. There, they react with molecules in the fuel
and even work at lower temperatures around 600°C. Unlike conventional SOFCS the BZY membranes allow the flow not of negatively charged oxygen ions toward the anode,
-cold atoms behaves like a single atom. Now the team claims that their black hole has produced just the kind of Hawking radiation expected of a real black hole.
which in turn decays to a stable isotope of iron producing characteristic gamma rays. Nobody had seen directly these gamma rays says Churazov.
Studying the water's isotopes and any organic material it might hold in deep freeze could shed light on where Earth got its water
made solely of positively or negatively charged ions. In the engine, a reservoir of ionic liquid soaks into a porous, metal chip and forms tiny pools in the pores of spikes on its surface.
so that it is strong enough to pull away ions in a steady beam (see below). The process is self-sustaining.
when ions are emitted, just as tree roots suck in water when vapour escapes the leaves. The result is an array of between 500 and 5000 focussed ion beams that stream from each of the eight chips on the Cubesat when the electric field the strength
of which acts as the engine's throttle is applied. Lozano's team have fired the thrusters in the lab
and carefully shaped magnetic field that stops xenon ions from hitting the engine walls and going to waste.
IBEX creates images of the solar system's borders by observing neutral atoms produced when charged particles from the solar wind collide with other charged particles in the outer heliosphere Some of these neutral atoms are bounced back towards us.
They are deflected not by magnetic fields as they travel so neutral atoms faithfully record the point of collision.
Because they travel pretty much straight you can trace them back to where they came from
and paint a picture of the solar system using atoms instead of light Christian says. One surprise is that
Our own sun and the Earth and all of us are made up of atoms that came out of other stars'stellar winds long ago says Mccomas. There's a big recycling process that occurs
so that it crashes into metal atoms releasing a jet of electrons and positrons. These particles are separated into two beams with magnets (Physical Review Letters doi. org/m2n.
whereas to make an anti-atom you also need antiprotons which are almost 2000 times more massive.
Normally levels of the isotope differ by just 0. 05 per cent annually but Miyake found a 1. 2 per cent leap in those years that could only have been caused by extremely high-energy cosmic rays hitting the Earth.
and European trees from the same era while Antarctic ice cores from 775 also have increases in beryllium-10 another isotope caused by cosmic rays.
The pair suggest that the odd isotope levels in the trees and in the Antarctic ice are the first evidence for a burst much closer to home.
which 99 percent of the chains carry nitroxides and 1 percent carry Cy5. 5. Nitroxides are reactive molecules that contain a nitrogen atom bound to an oxygen atom with an unpaired electron.
We often use the term artificial atoms in the community to describe how we are exploiting a new periodic table of fundamental building blocks to design materials
electrostatic forces to eject streams of ions. The technology has a range of promising applications:
array that generates 10 times the ion current per emitter that previous arrays did. Ion current is a measure of the charge carried by moving ions
which translates directly to the rate at which particles can be ejected. Higher currents thus promise more-efficient manufacturing and more-nimble satellites.
which droplets clumps of molecules rather than ions individual molecules begin streaming off of the emitters.
The ions ejected by Velsquez-Garc a s prototype are produced from an ionic salt that s liquid at room temperature.
Slow the flowwhen the ion current in an emitter gets high enough droplet formation is inevitable.
Increasing an array s ion current is a matter of regulating the flow of the ionic salt up the emitters sides.
But in the new work they instead used carbon nanotubes atom-thick sheets of carbon rolled into cylinders grown on the slopes of the emitters like trees on a mountainside.
and height of the nanotubes the researchers were able to achieve a fluid flow that enabled an operating ion current at very near the theoretical limit.
Typically the interest of this type of emitter is to be able to emit a beam of ions
Using their nanotube forest they re able to get the devices to operate in pure ion mode
The reason you d like to be in ion mode is to have the most efficient conversion of the mass of the propellant into the momentum of the spacecraft t
Instead the changes influenced their electrochemical membrane gradients differences in ion concentrations inside and outside the membrane
When a second smaller field perturbs the atoms they should all change their spins in synchrony
Battery pileup ahead One motivation for using the lead in old car batteries is that battery technology is undergoing rapid change, with new, more efficient types, such as lithium-ion batteries,
or pumps that influence electrical activity by controlling the flow of ions in or out of cells.
which provoke calcium ions to stream into each cell as it fires. By engineering fluorescent proteins to glow when they bind calcium,
The samples were made of four types of exciton fission molecules decorated with various sorts of pinachbulky side groups of atoms that change the molecular spacing without altering the physics or chemistry.
Each molecule has about 50 atoms, and each atom has six to 10 electrons. hese are complicated systems to calculate,
Van Voorhis says. hat the reason that 50 years ago they couldn compute these things
The system s powertrain includes an electric traction motor a lithium-ion battery advanced power converters
XL Hybrids installs small 1. 8-kwh lithium-ion batteries that provide a 20 percent fuel savings Hynes says.
The new findings using a layer of one-atom-thick graphene deposited on top of a similar 2-D layer of a material called hexagonal boron nitride (hbn) are published in the journal Nano Letters.
Although the two materials are structurally similar both composed of hexagonal arrays of atoms that form two-dimensional sheets they each interact with light quite differently.
run a large booth of"Atoms and Molecules"kits. Tan and Vandiver had a lot to be excited about:
the researchers are able to directly observe individual atoms at the interface of two surfaces
By changing the spacing of atoms on one surface, they observed a point at which friction disappears.
and an ion crystal. The optical lattice was generated using two laser beams traveling in opposite directions,
When atoms travel across such an electric field, they are drawn to places of minimum potential in this case, the troughs.
an ion crystal essentially, a grid of charged atoms in order to study friction effects, atom by atom.
To generate the ion crystal, the group used light to ionize, or charge, neutral ytterbium atoms emerging from a small heated oven,
and then cooled them down with more laser light to just above absolute zero. The charged atoms can then be trapped using voltages applied to nearby metallic surfaces.
Once positively charged, each atom repels each other via the so-called oulomb force. The repulsion effectively keeps the atoms apart,
so that they form a crystal or latticelike surface. The team then used the same forces that are used to trap the atoms to push
and pull the ion crystal across the lattice, as well as to stretch and squeeze the ion crystal,
much like an accordion, altering the spacing between its atoms. An earthquake and a caterpillarin general, the researchers found that
when atoms in the ion crystal were spaced regularly, at intervals that matched the spacing of the optical lattice, the two surfaces experienced maximum friction,
much like two complementary Lego bricks. The team observed that when atoms are spaced so that each occupies a trough in the optical lattice,
when the ion crystal as a whole is dragged across the optical lattice, the atoms first tend to stick in the lattice troughs,
bound there by their preference for the lower electric potential, as well as by the Coulomb forces that keep the atoms apart.
If enough force is applied, the ion crystal suddenly slips, as the atoms collectively jump to the next trough. t like an earthquake,
Vuletic says. here force building up, and then there suddenly a catastrophic release of energy. he group continued to stretch
and squeeze the ion crystal to manipulate the arrangement of atoms, and discovered that if the atom spacing is mismatched from that of the optical lattice,
friction between the two surfaces vanishes. In this case the crystal tends not to stick then suddenly slip,
but to move fluidly across the optical lattice, much like a caterpillar inching across the ground.
For instance, in arrangements where some atoms are in troughs while others are at peaks, and still others are somewhere in between,
as the ion crystal is pulled across the optical lattice, one atom may slide down a peak a bit,
releasing a bit of stress, and making it easier for a second atom to climb out of a trough
which in turn pulls a third atom along, and so on. hat we can do is adjust at will the distance between the atoms to either be matched to the optical lattice for maximum friction,
or mismatched for no friction, Vuletic says. Gangloff adds that the group technique may be useful
not only for realizing nanomachines, but also for controlling proteins, molecules, and other biological components. n the biological domain, there are various molecules
and atoms in contact with one another, sliding along like biomolecular motors, as a result of friction or lack of friction, Gangloff says. o this intuition for how to arrange atoms so as to minimize
or maximize friction could be applied. obias Schaetz, a professor of physics at the University of Freiburg in Germany, sees the results as a lear breakthroughin gaining insight into therwise inaccessible fundamental physics.
The technique he says, may be applied to a number of areas, from the nanoscale to the macroscale. he applications and related impact of their novel method propels a huge variety of research fields investigating effects relevant from raft tectonics down to biological systems
and motor proteins, says Schaetz, who was involved not in the research. ust imagine a nanomachine where we could control friction to enhance contact for traction,
or mitigate drag on demand. his work was funded in part by the National Science Foundation and the National Science and Engineering Research Council of Canada a
#New manufacturing approach slices lithium-ion battery cost in half An advanced manufacturing approach for lithium-ion batteries, developed by researchers at MIT and at a spinoff company called 24m,
The existing process for manufacturing lithium-ion batteries, he says, has changed hardly in the two decades
for high-energy density devices such as lithium-ion batteries, the extra complexity and components of a flow system would add unnecessary extra cost.
e realized that a better way to make use of this flowable electrode technology was to reinvent the lithium ion manufacturing process. nstead of the standard method of applying liquid coatings to a roll of backing material,
While conventional lithium-ion batteries are composed of brittle electrodes that can crack under stress the new formulation produces battery cells that can be bent,
With traditional lithium-ion production plants must be built at large scale from the beginning in order to keep down unit costs,
and go-no go decisions. iswanathan adds that 24m new battery design ould do the same sort of disruption to lithium ion batteries manufacturing as
and one atom of sulfur. To test the impact of the SCW, they performed two parallel experiments.
forming a smaller molecule with the sulfur atom in a very reactive form. In the absence of water, that highly reactive sulfur-bearing molecule would join with others like itself to form a long chain
#Researchers use oxides to flip graphene conductivity Graphene a one-atom thick lattice of carbon atoms is touted often as a revolutionary material that will take the place of silicon at the heart of electronics.
To resolve that imbalance you could have other ions come in and bond or have the oxide lose
Now if the oxide surface says'I wish I had more negative charge'instead of the oxide gathering ions from the environment
or by binding ions from the aqueous solution the researchers were able to show the relationship between the polarization of the oxide
#Researchers make magnetic graphene Graphene a one-atom thick sheet of carbon atoms arranged in a hexagonal lattice has many desirable properties.
Researchers find magnetic state of atoms on graphene sheet impacted by substrate it's grown on More information:
The way atoms line up along the edge of a ribbon of graphenehe atom-thick form of carbonontrols
with each six-atom unit forming a hexagon. The edges of pristine zigzags look like this://Turning the hexagons 30 degrees makes the edges"armchairs"
which atoms in graphene are enticed to shift around to form connected rings of five and seven atoms.
Yakobson, Zhang and Rice postdoctoral researcher Alex Kutana used density functional theory, a computational method to analyze the energetic input of every atom in a model system,
photoacoustic and radionuclide imaging abilities that the agent possesses.""Lovell says the next step in the research is to explore additional uses for the technology.
An electric field at the nozzle opening causes ions to form on the meniscus of the ink droplet.
The electric field pulls the ions forward deforming the droplet into a conical shape. Then a tiny droplet shears off and lands on the printing surface.
#Stacking two-dimensional materials may lower cost of semiconductor devices A team of researchers led by North carolina State university has found that stacking materials that are only one atom thick can create semiconductor junctions that transfer charge efficiently regardless of
which the spacing between the atoms in the two materials doesn't align. Essentially you can think of lattice mismatch as having a row of smaller boxes on the bottom layer and larger boxes on the top layer.
The mismatch can be handled by the first two layers of gold atoms creating the core-shell effect
The arrangement of atoms is the same in the two materials but the distance between atoms is said different Argonne postdoctoral researcher Soon Gu Kwon.
Eventually this becomes unstable and the growth of the gold becomes unevenly distributed. As the gold continues to accumulate on one side of the seed nanoparticle small quantities slide down the side of the nanoparticle like grains of sand rolling down the side of a sand hill creating the dumbbell shape.
He describes the thread's width as phenomenally small only a few atoms across hundreds of thousands of times smaller than an optical fiber enormously thinner that an average human hair.
Then as the researchers slowly release the pressure the atoms reconnect in an entirely different yet very orderly way.
That the atoms of the benzene molecules link themselves together at room temperature to make a thread is shocking to chemists and physicists.
when the benzene molecule breaks under very high pressure its atoms want to grab onto something else
You can attach all kinds of other atoms around a core of carbon and hydrogen.
The dream is to be able to add other atoms that would be incorporated into the resulting nanothread.
#Nanoparticle network could bring fast-charging batteries (Phys. org) A new electrode design for lithium-ion batteries has been shown to potentially reduce the charging time from hours to minutes by replacing the conventional graphite electrode with a network of tin-oxide nanoparticles.
The anodes in most of today's lithium-ion batteries are made of graphite. The theoretical maximum storage capacity of graphite is limited very at 372 milliamp hours per gram hindering significant advances in battery technology said Vilas Pol an associate professor of chemical engineering at Purdue University.
but rather gold ions",explains Falk Münch, a postdoctoral researcher and supervisor of Felix'Phd thesis. The gold ions that are dissolved in the precipitation bath are transformed into metallic gold after absorbing electrons.
Additional, harmless chemicals are required for the process. But the procedure is green not only because of the nontoxic substances,
a round film is bombarded vertically with an ion beam. Each ion leaves a straight track in the film
which then becomes a small hole, or, when seen through the microscope: a channel that is then etched.
an ion accelerator is needed to generate an ion beam. The TU scientists found the ideal partner for their research in the GSI Helmholtz Center for Heavy ion Research at the outskirts of Darmstadt;
but the GSI's large-scale accelerator was not suitable for subsequent commercial use for financial reasons.
Silicon sponge improves lithium-ion battery performance More information: Yang He Daniela Molina Piper Menggu Jonathan J. Travis Steven M. George Se-Hee Lee Arda Genc Lee Pullan Jun Liu
Computer simulations sharpen insights into molecules The resolution of scanning tunnelling microscopes can be improved dramatically by attaching small molecules or atoms to their tip.
One-atom thick material graphene first isolated and explored in 2004 by a team at The University of Manchester is renowned for its barrier properties
For example it would take the lifetime of the universe for hydrogen the smallest of all atoms to pierce a graphene monolayer.
The Manchester group also demonstrated that their one-atom-thick membranes can be used to extract hydrogen from a humid atmosphere.
Last a technique known as anisotropic ion beam milling (IBM) is used to etch through the mask to make an array of holes creating the nanoporous metal.
but it allows us to come up with far better maps of small objects than is possible with other methods-even individual atoms can be observed this way.
which are only one atom thick onto arbitrary substrates paving the way for flexible computing or photonic devices.
At issue are molybdenum sulfide (Mos2) thin films that are only one atom thick first developed by Dr. Linyou Cao an assistant professor of materials science and engineering at NC State.
Cao's team makes Mos2 films that are an atom thick and up to 5 centimeters in diameter.
To put that challenge in perspective an atom-thick thin film that is 5 centimeters wide is equivalent to a piece of paper that is as wide as a large city Cao said.
and then the tip apex was exposed via focused ion beam milling carried out at the CNM Electron microscopy Center (EMC).(
Both that remarkable resolution and the precise chemical fingerprinting of individual nickel nanoclusters were also clearly evident in the topographic images of the sample surface even down to the height of a single atom.
-and compressive strength-its ability to support weight-are valuable characteristics for these materials because at just a few atoms thick their utility figures almost entirely on their physical versatility.
Take the electrode of the small lithium-ion battery that powers your watch for example ideally the conductive material in that electrode would be very small
because it slightly enlarges the interlayer space between MXENE flakes allowing ions to penetrate deep into the electrode;
ions also stay trapped near the MXENE flakes by the polymer. With these conductive electrodes and no liquid electrolyte we can eventually eliminate metal current collectors
or focus ion beam lithography that often results in strongly anisotropic and small-scale metamaterials. People build metamaterials using top-down methods that include light exposure
Molybdenum disulfide isn't quite as flat as graphene the atom-thick form of pure carbon
because it contains both molybdenum and sulfur atoms. When viewed from above it looks like graphene with rows of ordered hexagons.
But seen from the side three distinct layers are revealed with sulfur atoms in their own planes above and below the molybdenum.
and high electrical conductivity and are used in products from baseball bats and other sports equipment to lithium-ion batteries and touchscreen computer displays.
One particular family of lithium-ion batteries composed of nickel cobalt and aluminum (NCA) offers high enough energy density a measure of the stored electricity in the battery that it works well in large-scale and long-range vehicles including electric cars and commercial aircraft.
As the battery cycles lithium ions shuttle back and forth between cathode and anode and leave behind detectable tracks of nanoscale damage.
The highly focused electron beams available at CFN revealed individual atom positions as an applied current pushed pristine batteries to an overcharged state.
To capture the atoms'electronic structures the scientists used electron energy loss spectroscopy (EELS. In this technique measurements of the energy lost by a well-defined electron beam reveal local charge densities and elemental configurations.
and began to shift toward disorder down at temperatures below 100 degrees Celsius definitely plausible for a lithium-ion battery's normal operation.
Overtext Web Module V3.0 Alpha
Copyright Semantic-Knowledge, 1994-2011