They discovered through neutron scattering experiments at BER II not only how the crystal structure changes, but also uncovered new magnetic phases.
Due to their different configurations of electrons, these tetrahedra become elongated along the crystallographic c-axis for nickel,
Phase diagramm between 2 and 900 Kelvin Using neutron scattering experiments at the BER II research reactor,
However, so far only electron holography could be considered for mapping magnetic domains of three-dimensional objects at the nanometre scale.
instead depends upon the uncanny ability of gold atoms to trap silicon-carrying electrons to selectively prevent the etching.
and purify major harmful substances of cigarette smoke. the KIST-developed catalyst removes 100%of the particle substances of cigarette smoke, such as nicotine and tar,
The wavelength of the infrared photon directed at a molecule is around 6 microns (6, 000 nanometres),
In this study, researchers first pattern nanostructures on the graphene surface by bombarding it with electron beams and etching it with oxygen ions.
the electrons in graphene nanostructures begin to oscillate. This phenomenon concentrates light into tiny spots,
Making graphene's electrons oscillate in different ways makes it possible to"read"all the vibrations of the molecule on its surface."
as supported by electron energy loss spectroscopy (EELS) measurements and also by the fact that no anelastic behaviour could be observed under tension.
The polyelectrolyte layer promotes the adhesion of the particles to bacterial cell membranes and, together with silver ions, can kill a broad spectrum of bacteria,
High-throughput bioactivity screening did not reveal increased toxicity of the particles when compared to an equivalent mass of metallic silver nanoparticles or silver nitrate solution.
and environmentally benign method to combat bacteria by engineering nanoscale particles that add the antimicrobial potency of silver to a core of lignin,
The remaining particles degrade easily after disposal because of their biocompatible lignin core, limiting the risk to the environment."
says that the particles could be the basis for reduced risk pesticide products with reduced cost and minimized environmental impact."
We are now working to scale up the process to synthesize the particles under continuous flow conditions."
harnessing its output for imaging applications that make microscopic particles appear huge.""The device makes an object super-visible by enlarging its optical appearance with this super-strong scattering effect,
Caltech researchers adopted a novel technique, ultrafast electron crystallography (UEC), to visualize directly in four dimensions the changing atomic configurations of the materials undergoing the phase changes.
"To study this, the researchers used their technique, ultrafast electron crystallography. The technique, a new development--different from Zewail's Nobel prize-winning work in femtochemistry, the visual study of chemical processes occurring at femtosecond scales--allowed researchers to observe directly the transitioning atomic configuration of a prototypical phase-change
followed by a pulse of electrons. The laser pulse causes the atomic structure to change from the crystalline to other structures
Then, when the electron pulse hits the sample, its electrons scatter in a pattern that provides a picture of the sample's atomic configuration as a function of the time.
This novel approach to using enzyme-directed assembly of particle theranostics (EDAPT) is patent pending.
or distorting the wavefront--analogous to the quantum tunneling effect, in which a particle crosses through a potential energy barrier otherwise insurmountable by classical mechanics.
and could be important for future device technologies as well as for fundamental studies of electron transport in molecular nanostructures.
In atomic-scale transistors, this current is extremely sensitive to single electrons hopping via discrete energy levels.
Single-electron transport in molecular transistors has been studied previously using top-down approaches, such as lithography and break junctions.
single electrons can tunnel between template and tip by hopping via nearly unperturbed molecular orbitals,
In our case, the charged atoms nearby provide the electrostatic gate potential that regulates the electron flow
and orientation has a dramatic effect on the electron flow across the molecule, manifested by a large conductance gap at low bias voltages.
which relocates the electrons from a dark state to a luminescent state, thereby increasing the material ability to convert electrons into light particles, or photons.
With this technique, the multilayer Mos2 semiconductors are at least as efficient as monolayer ones. Duan team is currently moving forward to apply this approach to similar materials,
carrying electrons with almost no resistance even at room temperature, a property known as ballistic transport. Graphene's unique optical, mechanical and electrical properties have lead to the one-atom-thick form of carbon being heralded as the next generation material for faster, smaller, cheaper and less power-hungry electronics."
Plasmonics study suggests how to maximize production of'hot electrons'Abstract: New research from Rice university could make it easier for engineers to harness the power of light-capturing nanomaterials to boost the efficiency
including metallic nanoparticles that convert light into plasmons, waves of electrons that flow like a fluid across the particles'surface.
or nanostructure is that you can excite some subset of electrons in the metal to a much higher energy level,
"Scientists call these'hot carriers'or'hot electrons.'"'"Halas, Rice's Stanley C. Moore Professor of Electrical and Computer engineering and professor of chemistry, bioengineering, physics and astronomy,
and materials science and nanoengineering, said hot electrons are particularly interesting for solar-energy applications because they can be used to create devices that produce direct current
"He and Halas said Manjavacas, a theoretical physicist in the group of LANP researcher Peter Nordlander, conducted work in the new study that offers a fundamental insight into the underlying physics of hot-electron-production
"To make use of the photon's energy, it must be absorbed rather than scattered back out.
"From this perspective, one can determine the total number of electrons produced, but it provides no way of determining how many of those electrons are actually useful, high-energy, hot electrons,
"Manjavacas said. He said Zheng's data allowed a deeper analysis because his experimental setup selectively filtered high-energy hot electrons from their less-energetic counterparts.
To accomplish this, Zheng created two types of plasmonic devices. Each consisted of a plasmonic gold nanowire atop a semiconducting layer of titanium dioxide.
and allowed only hot electrons to pass from the gold to the semiconductor. The second setup allowed all electrons to pass."
"The experiment clearly showed that some electrons are hotter than others, and it allowed us to correlate those with certain properties of the system,
"Manjavacas said.""In particular, we found that hot electrons were correlated not with total absorption. They were driven by a different, plasmonic mechanism known as field-intensity enhancement."
"LANP researchers and others have spent years developing techniques to bolster the field-intensity enhancement of photonic structures for single-molecule sensing and other applications.
Zheng and Manjavacas said they are conducting further tests to modify their system to optimize the output of hot electrons.
the resulting increase in length and decrease in cross-sectional area restricts the flow of electrons through the material.
because electrons can travel over such a hierarchically buckled sheath as easily as they can traverse a straight sheath."
The researchers report in Nano Letters that by combining inorganic semiconductor nanocrystals with organic molecules, they have succeeded in"upconverting"photons in the visible and near-infrared regions of the solar spectrum."
The hybrid material we have come up with first captures two infrared photons that would normally pass right through a solar cell without being converted to electricity,
then adds their energies together to make one higher energy photon. This upconverted photon is absorbed readily by photovoltaic cells,
generating electricity from light that normally would be wasted.""Bardeen added that these materials are essentially"reshaping the solar spectrum
The cadmium selenide nanocrystals could convert visible wavelengths to ultraviolet photons, while the lead selenide nanocrystals could convert near-infrared photons to visible photons.
In lab experiments the researchers directed 980-nanometer infrared light at the hybrid material, which then generated upconverted orange yellow fluorescent 550-nanometer light,
almost doubling the energy of the incoming photons. The researchers were able to boost the upconversion process by up to three orders of magnitude by coating the cadmium selenide nanocrystals with organic ligands,
but are good at combining two lower energy photons to a higher energy photon. By using a hybrid material,
the inorganic component absorbs two photons and passes their energy on to the organic component for combination.
The organic compounds then produce one high-energy photon. Put simply, the inorganics in the composite material take light in;
"Besides solar energy, the ability to upconvert two low energy photons into one high energy photon has potential applications in biological imaging, data storage and organic light-emitting diodes.
from red to blue, can impact any technology that involves photons as inputs or outputs,
The colloid form of these particles have very interesting properties and characteristics, and their size, shape and properties at nanometric scale can be controlled very well.
which are affected by the morphology of the particles, prevent the easily formation of a stable colloid.
The asymmetry of a p-n junction presents the electrons with an"on/off"transport environment.
"Electron flow at molecular length-scales is dominated by quantum tunneling, "Neaton explains.""The efficiency of the tunneling process depends intimately on the degree of alignment of the molecule's discrete energy levels with the electrode's continuous spectrum.
in nearly perfect alignment with the Fermi electron energy levels of the gold electrodes. Symmetry was broken by a substantial difference in the size of the area on each gold electrode that was exposed to the ionic solution.
The bilayer structure blocks the injection of electrons into the sol-gel material providing low leakage current, high breakdown strength and high energy extraction efficiency."
and shuttle data with light instead of electrons. Electrical and computer engineering associate professor Rajesh Menon and colleagues describe their invention today in the journal Nature Photonics Silicon photonics could significantly increase the power and speed of machines such as supercomputers
"But that information has to be converted to electrons when it comes into your laptop. In that conversion, you're slowing things down.
"Photons of light carry information over the Internet through fiber-optic networks. But once a data stream reaches a home or office destination,
the photons of light must be converted to electrons before a router or computer can handle the information.
And because photonic chips shuttle photons instead of electrons, mobile devices such as smartphones or tablets built with this technology would consume less power,
Light interaction with graphene produces particles called plasmons while light interacting with hbn produces phonons.
which ions and electrons must rapidly move. Researchers have built arrays of nanobatteries inside billions of ordered,
and electrons can do their job in such ultrasmall environments. Up to a billion of these nanopore batteries could fit in a grain of sand.
The nanobatteries were fabricated by atomic layer deposition to make oxide nanotubes (for ion storage) inside metal nanotubes for electron transport, all inside each end of the nanopores.
and out and close contact between the thin nested tubes to ensure fast transport for both ions and electrons.
and electron transport in nanostructures for energy storage and to test the limits of 3-D nanobattery technology y
and gaining a previously unattainable understanding of processes such as electron, water or ion transport or chemical reactions.
and its physical characteristics are determined by the complex interactions between atoms and electrons. Theoreticians use quantum mechanics to calculate the forces between atoms,
and the behaviour of electrons in materials. Specifically, first-principles simulations are based on quantum mechanics, and are a powerful technique widely used to uncover diverse properties of matter and materials at the atomic scale.
As the beam hits these molecules, it can produce photons that have a different frequency from the laser light.
#Exciton, exciton on the wall Researchers have observed, in metals for the first time, transient excitons the primary response of free electrons to light.
Here, the researchers discovered that the surface electrons of silver crystals can maintain the excitonic state more than 100 times longer than for the bulk metal,
which excite coherent three-photon photoemission at a single crystal silver surface. The interferogram is taken from a movie of photoelectron energy vs. momentum with one frame corresponding to a 50-attosecond delay.
the light shakes the metals free electrons and the resulting acceleration of electrons creates a nearly perfect replica of the incident light providing a reflection.
Excitons, or particles of the light-matter interaction where light photons become temporarily entangled with electrons in molecules
This discovery sheds light on the primary excitonic response of solids which could allow quantum control of electrons in metals, semiconductors,
It also potentially allows for the generation of intense femotosecond electron pulses that could increase resolution for time-resolved electron microscopes that follow the motion of individual atoms
The key is the structuring of this layer-the protective particles arrange themselves like roof tiles.
As in a wall, several layers of particles are placed on top of each other in an offset arrangement;
The specially formulated mixture contains a solvent, a binder and nanoscale and platelet-like particles;
have allowed snapshot imaging of a single 300 nm gold nanocrystal in the picosecond time interval after the particle was excited with a laser.
while preserving the integrity and large surface area of the particle. Ian Robinson, coordinator of the project said"Bragg Coherent Diffraction Imaging is an emerging X-ray technique with great potential for probing the dynamics of matter.
it is absorbed by electrons in the gold arms. The arms are so thin that the electrons are forced to move along the spiral.
Electrons that are driven toward the center absorb enough energy so that some of them emit blue light at double the frequency of the incoming infrared light.
This is similar to what happens with a violin string when it is bowed vigorously, said Stevenson Professor of Physics Richard Haglund,
The electrons at the center of the spirals are driven pretty vigorously by the lasers electric field.
because the polarization pushes the electrons toward the center of the spiral. Counterclockwise polarized light,
because the polarization tends to push the electrons outward so that the waves from all around the nano-spiral interfere destructively.
So far, Davidson has experimented with small arrays of gold nano-spirals on a glass substrate made using scanning electron-beam lithography.
which half of the electronic states that can contribute to the material electrical conductivity are occupied by electrons,
because electrons can freely travel around by moving in and out of the empty sites. In this organic material,
however, strong repulsion between the electrons in the full and empty states suppresses free movement.
triangular patterns (Fig. 1) removes the freedom of the electrons'spin such that the molecules line up
The only way for electrons to break free is to forcefully add additional electrical charge to the system,
and manage digital information by using the spin of electrons. Metal complexes showing spin-transition (i e. reversible interconversion between different isomers) are among the best candidates for the preparation of molecular memories and spintronic devices.
Semiconductor QDS can produce full-color luminescence through tuning of the particle size. QDS have attracted significant attention as potential components of next-generation solid-state light sources,
San diego. Shawkey and his team sought to produce synthetic particles that mimic the tiny packets of melanin found in feathers.
a magnetic field guides the plasma and filters out any particles of dirt. The laser arc method can be used to deposit very thick ta-C coatings of up to 20 micrometers at high coating rates.
One Dalton is roughly the mass of a proton or neutron, and several thousand Daltons are the mass of individual proteins and DNA molecules.
it'll capture the viral particles in the analyzed environment. Oscillations will occur at a lower
configured to detect different particles or molecules. The price, thanks to the simplicity of the design, will most likely depend on the number of sensors,
simple process for making platinum"nano-raspberries"microscopic clusters of nanoscale particles of the precious metal("Stability and phase transfer of catalytically active platinum nanoparticle suspensions").
The raspberry color suggests the particles? corrugated shape, which offers high surface area for catalyzing reactions in fuel cells.
Individual particles are 3-4 nm in diameter but can clump into bunches of 100 nm
To learn how such formulas affect particle properties, the NIST team measured particle clumping in four different solvents for the first time.
For applications such as liquid methanol fuel cells, catalyst particles should remain separated and dispersed in the liquid,
not clumped.""Our innovation has little to do with the platinum and everything to do with how new materials are tested in the laboratory,
We made the particles in water and tested whether you could put them in other solvents.
"The NIST team measured conditions under which platinum particles, ranging in size from 3 to 4 nanometers (nm) in diameter,
the researchers concluded that the particles could be transferred to that solvent, assuming they were to be used within a few dayseffectively putting an expiration date on the catalyst t
A short time after excitation, the initial excitation of Argon's eighteen electrons (blue spheres) is observed at several places within cluster.
At longer times after excitation, many excited electrons are see escaping the cluster in all directions.
The x-ray electron-free laser (XFEL) is the perfect example of new technology and old perceptions converging on that narrow boundary between science and science fiction.
Firing pulses of a trillion x-ray photons at molecular-sized samples in time scales on the order of million-billionths of a second (femtoseconds
researchers are aiming for the Holy grail of ultra-fast X-ray Science single-particle 3d imaging with atomic resolution.
Understanding the effects that these ultra-intense x-ray pulses will have on their potential targets will take the team work of Argonne National Laboratorys Advanced Photon Source (APS) and the Argonne Leadership Computing Facility (ALCF), both
when x-ray photons collide with the electrons of a target samplea specific atom or enzyme molecule, for instanceand scatter.
These scatterings are captured as images by photon detectors inside the machine. From the dizzying cascade of lines
there emerges the information necessary to detect the electron locations of the sample before it was irradiated,
The photon/electron collisions create infinite and simultaneous quantum reactions, where electrons emerge and disappear and new particles propagate,
all of them creating those frantic lines etched on the detectors. To read between the lines, quite literally, Young
and Ho work closely with computational scientists at the ALCF to optimize their method within a molecular simulation program called LAMMPS.
Where the MD tracks the time evolution for all the particles in the system MC incorporates detailed information from quantum mechanics to simulate the interactions between the electrons and the XFEL pulses.
So MC takes all of the complicated quantum mechanics and recasts it in a simpler way, says ALCF assistant computational scientist, Chris Knight.
The blast from the intense x-ray pulse produces more than a 10-fold increase in the number of particles,
But rather than try to calculate every electronic structure and excited particle during a simulation
and track the electronic configuration of every particle interacting with an x-ray pulse. Even with a computational cost significantly smaller than fully quantum mechanical simulations, some unique computational challenges remain before the team can exploit the full potential of the hybrid method.
The team continues to tweak the hybrid code as well as pulse rates by studying Argon clusters composed of 20 thousand to 2 million particles,
and nanodiamond materials composed of 1-100 million particles, with an end goal of mapping the electron pathways created by XFEL bursts.
According to Young, small bursts produce very high-resolution scattering patterns, while large bursts create radiation damage, causing smeared patterns and lower resolution.
the APS will not conduct single-shot single-particle imaging studies, though the question of radiation damage still will apply.
#Hematite're-growth'smoothes rough edges for clean energy harvest (Nanowerk News) Finding an efficient solar water splitting method to mine electron-rich hydrogen for clean
Tunneling electrons from a scanning tunneling microscope tip excites phonons in graphene. The image shows the graphene lattice with blue arrows indicating the motion direction of that carbon atoms for one of the low energy phonon modes in graphene.
issue of Physical Review Letters("Strong Asymmetric Charge Carrier Dependence in Inelastic Electron Tunneling Spectroscopy of Graphene Phonons").
One way to measure these tiny vibrations is to bounce electrons off the material and measure how much energy the electrons have transferred to the vibrating atoms.
But it's difficult. The technique, called inelastic electron tunneling spectroscopy, elicits only a small blip that can be hard to pick out over more raucous disturbances."
"Researchers are faced frequently with finding ways to measure smaller and smaller signals, "says NIST researcher Fabian Natterer,
such as that supplied by the electrons in a scanning tunneling microscope (STM). To filter the phonons'signal from other distractions,
NIST researchers used their STM to systematically alter the number of electrons moving through their graphene device.
As the number of electrons were varied, the unwanted signals also varied in energy, but the phonons remained fixed at their characteristic frequency.
Averaging the signals over the different electron concentrations diluted the annoying disturbances, but reinforced the phonon signals.
which become filled with electrons and stop the phonons from vibrating when we switch from hole to electron doping."
"The team notes that this effect is similar to resonance-induced effects seen in small molecules.
and corresponding author of a paper describing this new analytical method in the journal Nature Communications("Surface Determination Through Atomically Resolved Secondary Electron Imaging").
and bulk atoms simultaneously, retaining much of the surface sensitivity of traditional SEM through secondary electrons.
Secondary electrons are the result of a highly energized beam of electrons striking a material
and causing atoms in the material to emit energy in the form of electrons rather than photons.
As a large portion of secondary electrons are emitted from the surface of a material in addition to its bulk they are good resources for obtaining information about atomic surface structure.
"Existing secondary electron image simulation methods had to be extended to take into account contributions from valence orbitals in the material,
These experiments were coupled with careful secondary electron image simulations, density functional theory calculations, and aberration-corrected high resolution transmission electron microscopy."
In photosynthesis, plants that are exposed to sunlight use carefully organized nanoscale structures within their cells to rapidly separate charges pulling electrons away from the positively charged molecule that is left behind,
The polymer donor absorbs sunlight and passes electrons to the fullerene acceptor; the process generates electrical energy.
because the electrons sometimes hop back to the polymer spaghetti and are lost. The UCLA technology arranges the elements more neatly like small bundles of uncooked spaghetti with precisely placed meatballs.
The fullerenes inside the structure take electrons from the polymers and toss them to the outside fullerene
which can effectively keep the electrons away from the polymer for weeks. When the charges never come back together,
This force causes an increasing percentage of electrons to start flowing in the rongdirection as the magnetic field is ramped up,
Superfast electrons cause extremely large magnetoresistance he faster the electrons in the material move, the greater the Lorentz force and thus the effect of a magnetic field, explains Binghai Yan, a researcher at the Max Planck Institute for Chemical Physics of Solids in Dresden.
and phosphorus. This material contains superfast charge carriers, known as relativistic electrons that move at around one thousandth the speed of light,
In the process, they discovered why the electrons are so fast and mobile. The material owes its exotic properties to unusual electronic states in niobium phosphide.
Some electrons in this material, known as a Weyl metal act as if they have no mass. As a result, they are able to move very rapidly.
Integrating high quality III-V materials on silicon is critical for getting the benefit of higher electron mobility to build transistors with improved power and performance for technology scaling at 7 nm and beyond.
an exciting world-record performance,'said study co-author Yi Cui, an associate professor of materials science and engineering at Stanford and of photon science at the SLAC National Accelerator Laboratory.
'Breaking down metal oxide into tiny particles increases its surface area and exposes lots of ultra-small,
'This process creates tiny particles that are connected strongly, so the catalyst has very good electrical conductivity and stability.'
The electrons necessary for this reaction travel through the external circuit, generating an electric current. A supercapacitor is similar to a battery in that it can generate and store electric current,
Using an engineered strain of Stenotrophomonas maltophilia to control particle size the team biosynthesized QDS using bacteria
when particle size falls to the range of a few ten nanometers where a single particle provides only a vanishingly small signal.
As a consequence, many investigations are limited to large ensembles of particles. Now, a team of scientists of the Laser spectroscopy Division of Prof.
There is thus a large interest to develop single-particle-sensitive techniques. Our approach is to trap the probe light used for imaging inside of an optical resonator,
in order to bring the particle step by step into its focus. At the same time the distance between both mirrors is adjusted such that the condition for the appearance of resonance modes is fulfilled.
we can determine the optical properties of the particles from the transmission signal quantitatively and compare it to the calculation.
when both absorptive and dispersive properties of a single particle were determined at the same time. This is interesting especially
if the particles are not spherical but e g. elongated. Then, the corresponding quantities depend on the orientation of the polarization of light with respect to the symmetry axes of the particle.
In our experiment we use gold nanorods (34x25x25 nm) and we observe how the resonance frequency shifts depending on the orientation of the polarization.
and is a very sensitive indicator for the shape and orientation of the particle. As an application of our method, we could think of e g. investigating the temporal dynamics of macro molecules,
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