A quantum dot is a collection of a few hundred thousand atoms that can form itself into a semiconductor under certain conditions.
Richard J. Warburton from the University of Basel have shown already in past publications that the indistinguishability of the photons is reduced by the fluctuating nuclear spin of the quantum dot atoms.
University of British columbia (UBC) physicists have been able to create the first ever superconducting graphene sample by coating it with lithium atoms.
Although superconductivity has already been observed in intercalated bulk graphite--three-dimensional crystals layered with alkali metal atoms,
"Decorating monolayer graphene with a layer of lithium atoms enhances the graphene's electron-phonon coupling to the point where superconductivity can be induced,
"Decorating monolayer graphene with a layer of lithium atoms enhances the graphene's electron-phonon coupling to the point where superconductivity can be stabilized."
University of British columbia (UBC) physicists have been able to create the first ever superconducting graphene sample by coating it with lithium atoms.
Although superconductivity has already been observed in intercalated bulk graphite--three-dimensional crystals layered with alkali metal atoms,
"Decorating monolayer graphene with a layer of lithium atoms enhances the graphene's electron-phonon coupling to the point where superconductivity can be induced,
"Decorating monolayer graphene with a layer of lithium atoms enhances the graphene's electron-phonon coupling to the point where superconductivity can be stabilized."
#Nano-dunes with the ion beam Many semiconductor devices in modern technology--from integrated circuits to solar cells and LEDS--are based on nanostructures.
for self-organization of nanostructured arrays via broad ion beam irradiation. The results have been published in the scientific journal Nanoscale.
the researchers use ion beams, which are charged fast, electrically atoms. They direct a broad beam of noble gas ions onto a gallium arsenide wafer, which,
for example, is used in producing high-speed and high-frequency transistors, photocells or light-emitting diodes.""One could compare ion bombardment with sand blasting.
This means that the ions mill off the surface of the target. There, the desired nanostructures are created all by themselves,
"explains Dr. Facsko. The finely chiselled and regular structure is reminiscent of sand dunes, natural structures created by wind.
It all occurs, however, in a nano-realm, with a mere distance of fifty nanometers between two dunes--strands of human hair are two thousand times thicker.
Ion Bombardment at Elevated Temperature At room temperature, however, the ion beam destroys the crystal structure of the gallium arsenide and thus its semiconducting properties.
Dr. Facsko's group at the HZDR's Ion beam Center therefore uses the opportunity to heat the sample during ion bombardment.
At about four hundred degrees Celsius, the destroyed structures recover rapidly. A further effect ensures that the nano-dunes on the semiconductor surface develop.
The colliding ions not only shift the atoms they hit, but also knock individual atoms entirely out of the crystal structure.
Since the volatile arsenic does not remain bound on the surface, the surface soon consists only of gallium atoms.
In order to compensate for the missing arsenic atom bonds, pairs of two gallium atoms form, which arrange themselves in long rows.
If the ion beam knocks out further atoms next to them, the gallium pairs cannot slip down the step that has been created
because the temperatures are too low for this to happen. This is how the long rows of gallium pairs form nano-dunes after a period of time, in
which several long pairs of lines lie next to each other. Many experiments at different temperatures and comprehensive computations were necessary to both preserve the crystalline state of the semiconducting material as well to produce the well-defined structures at the nanoscale.
Because we use particularly low energy ions--under 1 kilovolt, -which can be generated using simple methods,
While the individual atoms in a natural material cannot be rearranged with pinpoint precision on such a grand scale,
#Physicists determine 3-D positions of individual atoms for the first time Atoms are the building blocks of all matter On earth,
Now, scientists at UCLA have used a powerful microscope to image the three-dimensional positions of individual atoms to a precision of 19 trillionths of a meter,
to infer the macroscopic properties of materials based on their structural arrangements of atoms, which will guide how scientists and engineers build aircraft components, for example.
For more than 100 years, researchers have inferred how atoms are arranged in three-dimensional space using a technique called X-ray crystallography,
However, X-ray crystallography only yields information about the average positions of many billions of atoms in the crystal
and not about individual atoms'precise coordinates.""It's like taking an average of people On earth,
"Because X-ray crystallography doesn't reveal the structure of a material on a per-atom basis,
the technique can't identify tiny imperfections in materials such as the absence of a single atom.
and measures how many electrons interact with the atoms at each scan position. The method reveals the atomic structure of materials
because different arrangements of atoms cause electrons to interact in different ways. However, scanning transmission electron microscopes only produce two-dimensional images.
769 atoms in the tip of the tungsten sample. The experiment was time consuming because the researchers had to wait several minutes after each tilt for the setup to stabilize."
Miao and his team showed that the atoms in the tip of the tungsten sample were arranged in nine layers, the sixth
The researchers believe the defect was either a hole in an otherwise filled layer of atoms
or one or more interloping atoms of a lighter element such as carbon. Regardless of the nature of the point defect, the researchers'ability to detect its presence is significant,
demonstrating for the first time that the coordinates of individual atoms and point defects can be recorded in three dimensions."
Miao and his team plan to build on their results by studying how atoms are arranged in materials that possess magnetism or energy storage functions,
Phase change materials that change their optical properties depending on the arrangement of the atoms allow for the storage of several bits in a single cell.
novel materials that change their optical properties depending on the arrangement of the atoms: Within shortest periods of time, they can change between crystalline (regular) and amorphous (irregular) states.
including one at NIST using atoms in 2004. Arraythe lead author, Hiroki Takesue, was a NIST guest researcher from NTT Corp. in Japan.
"Previously, researchers thought quantum repeaters might need to rely on atoms or other matter, instead of light,
or ion channels, each of which is a portal for specific ions. Ion channels are typically about 1 nanometer wide;
by maintaining the right balance of ions, they keep cells healthy and stable. Now researchers at MIT have created tiny pores in single sheets of graphene that have an array of preferences and characteristics similar to those of ion channels in living cells.
which scientists have studied ever ion flow. Each is also uniquely selective, preferring to transport certain ions over others through the graphene layer."
"What we see is that there is a lot of diversity in the transport properties of these pores,
detecting ions of mercury, potassium, or fluoride in solution. Such ion-selective membranes may also be useful in mining:
In the future, it may be possible to make graphene nanopores capable of sifting out trace amounts of gold ions from other metal ions, like silver and aluminum.
Karnik and former graduate student Tarun Jain, along with Benjamin Rasera, Ricardo Guerrero, Michael Boutilier, and Sean O'Hern from MIT and Juan-carlos Idrobo from Oak ridge National Laboratory, publish their results in the journal Nature Nanotechnology.
which are slightly smaller than the ions that flow through them.""When nanopores get smaller than the hydrated size of the ion,
then you start to see interesting behavior emerge, "Jain says. In particular, hydrated ions, or ions in solution, are surrounded by a shell of water molecules that stick to the ion,
depending on its electrical charge. Whether a hydrated ion can squeeze through a given ion channel depends on that channel's size and configuration at the atomic scale.
Karnik reasoned that graphene would be a suitable material in which to create artificial ion channels:
A sheet of graphene is an ultrathin lattice of carbon atoms that is one atom thick, so pores in graphene are defined at the atomic scale.
To create pores in graphene, the group used chemical vapor deposition, a process typically used to produce thin films.
The researchers then isolated individual pores by placing each graphene sheet over a layer of silicon nitride that had been punctured by an ion beam
The group reasoned that any ions flowing through the two-layer setup would have passed likely first through a single graphene pore,
The group measured flows of five different salt ions through several graphene sheet setups by applying a voltage and measuring the current flowing through the pores.
and from ion to ion, with some pores remaining stable, while others swung back and forth in conductance--an indication that the pores were diverse in their preferences for allowing certain ions through."
"The picture that emerges is that each pore is different and that the pores are dynamic,
which--given the single-atom thickness of graphene--makes them among the smallest pores through
which scientists have studied ion flow. With the model, the group calculated the effect of various factors on pore behavior,
Knowing this, researchers may one day be able to tailor pores at the nanoscale to create ion-specific membranes for applications such as environmental sensing and trace metal mining."
it is due to the canting between the atomic magnets from one atom to the next. The larger the angle between the adjacent atomic magnets, the stronger is the change in electrical resistance.'
a process of aligning atoms inside a diamond so they create a signal detectable by an MRI SCANNER."
Graphene is a two-dimensional sheet of carbon atoms, just one atom thick. Its flexibility, optical transparency and electrical conductivity make it suitable for a wide range of applications,
The researchers also used an analytic technique to determine the fractionation of the stable isotopes of one of these contaminants,
which carries a supply of iron atoms that every cell needs as components of metabolic enzymes.
VRAC is regulated a volume anion channel that allows negatively charged ions (anions) and amino acids into the cell and back out again.
"ORNL researchers tracked the molecular transition in labeling experiments with deuterium, a hydrogen isotope, to confirm the hydrocarbon pool mechanism.
In the future, these infections will be prevented thanks to a new plasma implant coating that kills pathogens using silver ions.
and during that time they continuously release small quantities of antimicrobial silver ions, which kill bacteria.
and the outermost layer releases the ions. This is beneficial because it prevents direct contact between the tissue and the silver particles,
This allows the silver ions to penetrate the outermost plasma polymer layer over a set period of time deemed necessary to properly integrate the implant.
no more silver ions are released, thus avoiding any long-term toxic effects. In trials using finished implants and titanium test samples
absorb silver ions and, as a result, end up dying. t UVA Dankovich and her colleagues started to test their filter pages in Limpopo province in South africa in 2013.
#Computer-Designed Rocker Protein Worlds First To Biomimic Ion Transport For the first time, scientists recreated the biological function of substrate transportation across the cell membranes by computationally designing a transporter protein.
was shown to transport ions across the membrane, a process crucial to cell and organismal survival in various functions,
designed so that zinc ions and protons can flow in a controlled way across the lipid-membrane barrier around the cell-like vesicle.
and to form two special pockets for binding zinc ions and protons along the cavity within the bundle.
One conformation opens up the pocket near one side of the membrane to grab zinc ions or protons.
Once the zinc ion binds to the pocket Rocker changes its shape to close off the pocket,
This allows the ions from the closed pocket to travel to the second pocket before being released to the outside of the membrane.
The catch is that Rocker can have both pockets bind the ions at the same time, nor permit the cavity to open all the way through the membrane at one time
because this would leak down the ion concentration levels important for keeping cells intact and healthy.
Also, Rocker reconstituted in membrane vesicles was tested to show that it really pushed zinc ions from one side of the membrane to the other,
But if you could transport something into the cell such as a toxic ion or small molecule that could be quite interesting,
Early success stories The Electrolyte Genome first major scientific findinghat magnesium electrolytes are very prone to forming ion pairs,
it has attached negative ions to its surface. It thus attracts small positively charged molecules, whether these are ions or drugs.
When an electrical current is applied to it the flow of electrons generated projects the molecules of interest toward the target area.
#Discovery unlocks ion conductor that is 100 times faster than all the others A research group at the Technical University of Denmark (DTU),
Department of energy Conversion and storage (DTU Energy) has discovered a new way to stabilize an ion conducting material with a 100 times faster ion conductivity than all previous known ion conductors. he new
the current is transported by oxygen ions. There has been enormous interest over the years to use this material in application however;
which exhibit the highest ionic conductivity and was discovered by L. G. Sillén (1916-1970)( Mineralogist,
with the hope that this discovery opens brand new possibilities for usingd-Bismuth as an ion conductor. e have used very advanced fabrication
What we know is that they have gained a new way to access the best ion conductor available.
hings like yttria or lutecia and and dope them with rare earth ions. NRL has transitioned both types of laser materials and applications to industry.
For example, antibodies can serve as transport vehicles for radionuclides, with which the affected regions can be visualized
The scientists coat gold nanoparticles of a few thousand atoms each with an oil-like organic molecule that holds the gold particles together.
or about six atoms thick, is so tiny it would not normally be measurable. Subramanian Sankaranarayanan and Sanket Deshmukh at CNM used the high-performance computing resources at DOE National Energy Research Scientific Computing Center and the Argonne Leadership Computing Facility (ALCF
At temperatures approaching absolute zero, atoms cease their individual, energetic trajectories, and start to move collectively as one wave.
if atoms cannot be kept cold or confined. The MIT team combined several techniques in generating ultracold temperatures,
the John D. Macarthur Professor of Physics at MIT. e use ultracold atoms to map out
originally co-developed by Ketterle, to cool atoms of rubidium to nanokelvin temperatures. Atoms of rubidium are known as bosons,
for their even number of nucleons and electrons. When cooled to near absolute zero bosons form what called a Bose-Einstein condensate a superfluid state that was discovered first co by Ketterle,
After cooling the atoms, the researchers used a set of lasers to create a crystalline array of atoms,
or optical lattice. The electric field of the laser beams creates what known as a periodic potential landscape, similar to an egg carton,
whether this could be done with ultracold atoms in an optical lattice. Since the ultracold atoms are charged not,
as electrons are, but are instead neutral particles, their trajectories are unaffected normally by magnetic fields. Instead, the MIT group came up with a technique to generate a synthetic
ultrahigh magnetic field, using laser beams to push atoms around in tiny orbits, similar to the orbits of electrons under a real magnetic field.
and two additional laser beams to control the motion of the atoms. On a flat lattice, atoms can easily move around from site to site.
However, in a tilted lattice, the atoms would have to work against gravity. In this scenario, atoms could only move with the help of laser beams. ow the laser beams could be used to make neutral atoms move around like electrons in a strong magnetic field
added Kennedy. Using laser beams, the group could make the atoms orbit, or loop around, in a radius as small as two lattice squares, similar to how particles would move in an extremely high magnetic field. nce we had the idea,
we were excited really about it, because of its simplicity. All we had to do was take two suitable laser beams
and carefully align them at specific angles, and then the atoms drastically change their behavior,
Kennedy says. ew perspectives to known physics After developing the tilting technique to simulate a high magnetic field,
and electronic controls to avoid any extraneous pushing of the atoms, which could make them lose their superfluid properties. t a complicated experiment, with a lot of laser beams, electronics,
During that time, the team took time-of-flight pictures of the distribution of atoms to capture the topology
but to add strong interactions between ultracold atoms, or to incorporate different quantum states, or spins.
Graphene is only one atom thick material, which conducts electricity and heat with such efficiency that it is likely to revolutionize electronics.
introducing certain types of ions or pushing ions out of the cells to alter electrical activity.
But without a feedback loop, scientists could only assume that the optical signals were having the effects desired
This involves exciting a single atom with just a tiny amount of light. The theory states that the light scattered by this atom should,
similarly, be squeezed. Unfortunately, although the mathematical basis for this method known as squeezing of resonance fluorescence was drawn up in 1981,
or photons, using an artificially constructed atom, known as a semiconductor quantum dot. Thanks to the enhanced optical properties of this system and the technique used to make the measurements,
because we now have artificial atoms with optical properties that are superior to natural atoms.
In the Cambridge experiment, the researchers achieved this by shining a faint laser beam on to their artificial atom, the quantum dot.
the researchers etched micrometer scale pillars into a silicon surface using photolithography and deep reactive-ion etching,
and Stanford university shows how individual atoms move in trillionths of a second to form wrinkles on a three-atom-thick material.
The electrons of the probe pulse scatter off the monolayer atoms (blue and yellow spheres)
which uses energetic electrons to take snapshots of atoms and molecules on timescales as fast as 100 quadrillionths of a second. his is published the first scientific result with our new instrument,
This animation explains how researchers use high-energy electrons at SLAC to study faster-than-ever motions of atoms and molecules relevant to important materials properties and chemical processes.
Until now, researchers only had limited a view of the underlying mechanisms. he functionality of 2-D materials critically depends on how their atoms move,
to take snapshots of a three-atom-thick layer of a promising material as it wrinkles in response to a laser pulse.
scatter off the sample atoms and produce a signal on a detector that scientists use to determine where atoms are located in the monolayer.
This technique is called ultrafast electron diffraction. Illustrations (each showing a top and two side views) of a single layer of molybdenum disulfide (atoms shown as spheres.
Top left: In a hypothetical world without motions, the dealmonolayer would be flat. Top right:
when atoms are brought too close together to detect a wide array of protein markers that are linked to various diseases.
when atoms are brought too close together to detect a wide array of protein markers that are linked to various diseases.
They have created a new type of lithium-ion battery anode using portabella mushrooms, which are inexpensive, environmentally friendly and easy to produce.
The current industry standard for rechargeable lithium-ion battery anodes is synthetic graphite, which comes with a high cost of manufacturing
Hierarchically Porous Carbon Anodes for Li-ion Batteries, published on Sept. 29 in the journal Nature Scientific Reports.
This paper involving mushrooms is published just over a year after the Ozkan labs developed a lithium-ion battery anode based on nanosilicon via beach sand as the natural raw material.
a nanomaterial consisting of graphite that is extremely thin measuring the thickness of a single atom.
by showing that potassium can work with graphite in a potassium-ion battery a discovery that could pose a challenge and sustainable alternative to the widely-used lithium-ion battery.
Lithium-ion batteries are ubiquitous in devices all over the world, ranging from cell phones to laptop computers and electric cars.
A potassium-ion battery has been shown to be possible. And the last time this possibility was explored was
as the charge carrier whose ions migrate into the graphite and create an electrical current.
Right now, batteries based on this approach don have performance that equals those of lithium-ion batteries,
he said. t safe to say that the energy density of a potassium-ion battery may never exceed that of lithium-ion batteries,
Graphene is a two-dimensional sheet of carbon atoms, just one atom thick. Its flexibility, optical transparency and electrical conductivity make it suitable for a wide range of applications,
these channels act like a doorman to regulate the entry of calcium ions in the nerve cells. t has also been known for a long time that following transient severe brain injury and prior to an initial spontaneous epileptic seizure, the concentration of free zinc ions
If the number of zinc ions increases following transient severe brain damage, these ions dock in greater numbers onto a switch, the so-called metal-regulatory transcription factor 1 (MTF1.
If the zinc ions or the transcription factor MTF1 were inhibited specifically in the brain, it is possible that the development of a seizure disorder could be prevented. owever,
Silver ions are released gradually from the tablet, killing pathogens by penetrating cell membranes and disrupting cell division.
The Illinois researchers and their collaborators addressed these challenges by attaching positively charged ions to the backbone of the spiral,
the team enlisted the help of co-authors postdoc Yi Shi and Brian Chait, the Camille and Henry Dreyfus Professor at Rockefeller and head of the Laboratory of Mass Spectrometry and Gaseous Ion Chemistry.
Unlike conventional drugs, where chemists exert exquisite control over the position of every atom, with proteins they mostly still need a living thing to do their manufacturing for them. hen you get to whole proteins,
#Algae inspiration could boost your phone's battery Materials engineers trying to work out a way of boosting the performance of lithium-ion batteries have hit upon an unlikely inspiration-algae from a local pond.
When compared to normal lithium-ion cells, the new batteries showed high reversible capacity, good cycling stability and high-rate performance."
the researchers found the tantalum oxide gradually loses oxygen ions, changing from an oxygen-rich, nanoporous semiconductor at the top, to oxygen-poor at the bottom.
the team said it was also safer than lithium-ion batteries as it was less prone to catching fire and more environmentally friendly than alkaline models such as AA and AAA.
and lithium-ion batteries, which occasionally burst into flames. Our new battery won catch fire, even if you drill through it. illions of consumers use 1. 5-volt AA and AAA BATTERIES.
while a typical lithium-ion battery lasts about 1, 000 cycles. his was the first time an ultra-fast aluminium-ion battery was constructed with stability over thousands of cycles,
the report authors wrote. Dai added that lithium batteries could o off in an unpredictable mannerand cited a ban by US airlines Delta
the lithium-ion batteries are designed to capture and store up to 10kwh of energy from wind or solar panel.
The Nevada facility will be the largest producer of lithium-ion batteries in the world and it is hoped its mass-production scale will help to bring down costs even further.
Sporting higher energy density than lithium-ion we may even see batteries made with this material.
Called sol-gel thin film, it is made up of a single layer of silicon atoms and a nanoscale self-assembled layer of octylphosphonic acid.
Performance of sol-gel thin film electrodes at Georgia Tech's laboratories has exceeded all existing commercial electrolytic capacitors and thin-film lithium-ion batteries.
This material--just a single layer of atoms--could be made as a wearable device perhaps integrated into clothing to convert energy from your body movement to electricity
when the size of material shrinks to the scale of a single atom Hone adds.
because each nucleotide has a slightly different distribution of electrons the negatively charged parts of the atoms.
The researchers extensively used the Blue waters supercomputer at the National Center for Supercomputing Applications housed at the University of Illinois. They mapped each individual atom in the complex DNA molecule
and are composed of 10-20 atoms that are segregated to the surface. The unique environment around the Pd-islands give rise to special effects that all together turn the islands into highly efficient catalytic hot-spots for oxygen reduction.
This is the first time that anyone has imaged directly single dopant atoms moving around inside a material said Rohan Mishra of Vanderbilt University who is also a visiting scientist in ORNL's Materials science and Technology Division.
Semiconductors which form the basis of modern electronics are doped by adding a small number of impure atoms to tune their properties for specific applications.
The study of the dopant atoms and how they move or diffuse inside a host lattice is a fundamental issue in materials research.
Traditionally diffusion of atoms has been studied through indirect macroscopic methods or through theoretical calculations. Diffusion of single atoms has previously been observed directly only on the surface of materials.
The experiment also allowed the researchers to test a surprising prediction: Theory-based calculations for dopant motion in aluminum nitride predicted faster diffusion for cerium atoms than for manganese atoms.
This prediction is surprising as cerium atoms are larger than manganese atoms. It's completely counterintuitive that a bigger heavier atom would move faster than a smaller lighter atom said the Material Science and Technology Division's Andrew Lupini a coauthor of the paper.
In the study the researchers used a scanning transmission electron microscope to observe the diffusion processes of cerium and manganese dopant atoms.
The images they captured showed that the larger cerium atoms readily diffused through the material
while the smaller manganese atoms remained fixed in place. The team's work could be applied directly in basic material design
and technologies such as energy saving LED LIGHTS where dopants can affect color and atom movement can determine the failure modes.
Diffusion governs how dopants get inside a material and how they move said Lupini. Our study gives a strategy for choosing
which dopants will lead to a longer device lifetime. The study was funded by the DOE Office of Science the Australian Research Council Vanderbilt University and the Japan Society for the Promotion of Science Postdoctoral Fellowship for research abroad.
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