and some of those photons interfere with one another and find their way onto a detector,
a computer then reconstructs the path those photons must have taken, which generates an image of the target material--all without the lens that's required in conventional microscopy."
The table-top machines are unable to produce as many photons as the big expensive ones
hardly any photons will bounce off the target at large enough angles to reach the detector.
Without enough photons, the image quality is reduced. Zürch and a team of researchers from Jena University used a special, custom-built ultrafast laser that fires extreme ultraviolet photons a hundred times faster than conventional table-top machines.
With more photons, at a wavelength of 33 nanometers, the researchers were able to make an image with a resolution of 26 nanometers--almost the theoretical limit."
"Nobody has achieved such a high resolution with respect to the wavelength in the extreme ultraviolet before, "Zürch said.
and cools it in a way that allows it to convert more photons into electricity. The work by Shanhui Fan, a professor of electrical engineering at Stanford, research associate Aaswath P. Raman and doctoral candidate Linxiao Zhu is described in the current issue of Proceedings of the National Academy
the less efficient they become at converting the photons in light into useful electricity. The Stanford solution is based on a thin,
because the optimum conditions for applying nanocomposite coating through electrophoretic method on metals are obtained at low particle size distributions s
The work demonstrates the potential of low energy electron holography as a non-destructive, single-particle imaging technique for structural biology.
The researchers describe their work in a paper published this week on the cover of the journal Applied Physics Letters, from AIP Publishing."
Low energy electron holography is a technique of using an electron wave to form holograms. Similar to light optical holography
"The low energy electron holography has two major advantages over conventional microscopy. First, the technique doesn't employ any lenses,
Second, low energy electrons are harmless to biomolecules, "Longchamp said. In many conventional techniques such as transmission electron microscopy, the possible resolution is limited by high-energy electrons'radiation damage to biological samples.
Individual biomolecules are destroyed long before an image of high enough quality can be acquired. In other words, the low permissible electron dose in conventional microscopies is not sufficient to obtain high-resolution images from a single biomolecule.
However in low energy electron holography, the employed electron doses can be much higher--even after exposing fragile molecules like DNA or proteins to a electron dose more than five orders of magnitude higher
than the critical dose in transmission electron microscopy, no radiation damage could be observed. Sufficient electron dose in low energy electron holography makes imaging individual biomolecules at a nanometer resolution possible.
In Longchamp's experiment, the tobacco mosaic virions were deposited on a freestanding, ultraclean graphene, an atomically thin layer of carbon atoms arranged in a honeycomb lattice.
which is conductive, robust and transparent for low energy electrons. To obtain the high-resolution hologram, an atomically sharp, tungsten tip acts as a source of a divergent beam of highly coherent electrons.
When the beam hits the sample, part of the beam is scattered and the other part is affected not.
"This is the first time to directly observe the helical structure of the unstained tobacco mosaic virus at a single-particle level,
"Since low energy electron holography is a method very sensitive to mechanical disturbance, the current nanometer resolution could be improved to angstrom (one ten billionth of a meter)
electrons flow from the anode through a circuit outside the battery and back into the cathode.
Having lost the electrons that are generating the current, some of the atoms in the anode--an electrically conductive metal like lithium--become ions that then travel to the cathode,
we have made two major advances--the ability to precisely control the brightness of light-emitting particles called quantum dots,
and tunable number of photons per tagged biomolecule. They are expected also to be used for precise color matching in light-emitting devices and displays,
and for photon-on-demand encryption applications. The same principles should be applicable across a wide range of semiconducting materials."
and magnetization in order to understand how to control electron spins (electron magnetic moments) and to create the new generation of electronics.
In spin electronics-or spintronics-information is coded via the electron spin, which could be directed along
that the spins of the electron and of other charged particles are very difficult to control.
During the experiments scientists bombarded the experimental samples with muons (particles that resemble electrons, but are 200 times heavier) and analyzed their dissipation scattering.
or high-energy reservoir of electrons. Lithium can do that, as the charge carrier whose ions migrate into the graphite
Skyrmions were described originally over 50 years ago as a type of hypothetical particle in nuclear physics. Actual magnetic skyrmions were discovered only in 2009,
Using neutron scattering at NIST Center for Neutron Research, they were able to resolve the magnetic profiles along the depth of the hybrid structure.
This finding is likely to spawn new developments in emerging technologies such as low-power electronics based on the spin of electrons or ultrafast quantum computers.
"The electrons in topological insulators have unique quantum properties that many scientists believe will be useful for developing spin-based electronics and quantum computers.
In Science Advances, the researchers report the discovery of an optical effect that allows them to"tune"the energy of electrons in these materials using light,
which arises from quantum interference between the different simultaneous paths electrons can take through a material
and electrons to read data. This could enable the size of storage cells to be reduced to atomic dimensions.
Standard memory devices are based on electrons which are displaced by applying voltage. The development of ever smaller and more energy-efficient storage devices according to this principle,
"Electrons are roughly 1000 times lighter than ions and so they move much more easily under the influence of an external voltage.
while the electrons remain mobile and can be used to read the storage status."The trick:
"The tunnel effect enables us to move electrons through the ultra-thin layer with very little energy,
and electrons, on the other hand, at voltages far below one volt. This way, ions can be used specifically for storing and electrons specifically for reading data.
The researchers also reported that their research had another very interesting element. The new resistance-based storage devices could even simulate brain structures.
which it then emits in the form of light particles. In this case, the light has a much lower frequency than ordinary light
They suggested that magnetic atoms introduced into a superconductor must create special states of excitation around themselves-electron-hole standing waves named after their discoverers.
One promising option is to use topologically protected electron states that are resistant to decoherence.
The theory predicts that such non-Abelian anyons may occur in a two-dimensional"liquid"of electrons in a superconductor under the influence of a local magnetic field.
The electron liquid thus becomes degenerate, i e. the electrons can have different states at the same energy level.
The superposition of several anyons cannot be affected without moving them, therefore they are protected completely from disturbances e
This phase, characterized by an unusual ordering of electrons, offers possibilities for new electronic device functionalities and could hold the solution to a longstanding mystery in condensed matter physics having to do with high-temperature superconductivity--the ability
first consider a crystal with electrons moving around throughout its interior. Under certain conditions, it can be energetically favorable for these electrical charges to pile up in a regular,
In addition to charge, electrons also have a degree of freedom known as spin. When spins line up parallel to each other (in a crystal, for example),
But what if the electrons in a material are ordered not in one of those ways?
And like the cuprates, iridates are electrically insulating antiferromagnets that become increasingly metallic as electrons are added to
where an additional amount of energy is required to strip electrons out of the material. For decades, scientists have debated the origin of the pseudogap
but uses photons--the quanta of light--instead of electrons. The biggest advantage of using photons is the absence of interactions between them.
As a consequence, photons address the data transmission problem better than electrons. This property can primarily be used for in computing where IPS (instructions per second) is the main attribute to be maximized.
The typical scale of eletronic transistors--the basis of contemporary electronic devices--is less than 100 nanometers
one of them interacts with the other and dampers it due to the effect of two-photon absorption.
--Free carriers (electrons and electron holes) place serious restrictions on the speed of signal conversion in the traditional integrated photonics.
Film in 4-D with ultrashort electron pulses Physicists of the Ludwig-Maximilians-Universität (LMU) in Munich shorten electron pulses down to 30 femtoseconds duration.
A team from Ludwig-Maximilians-Universität (LMU) and Max Planck Institute of Quantum Optics (MPQ) has managed now to shorten electron pulses down to 28 femtoseconds in duration.
Sharp images of moving atoms Electrons are odd particles: they have both wave and particle properties.
Electron microscopy has been taking advantage of this phenomenon for roughly a century now and grants us a direct insight into the fundamental components of matter:
They create beams of electron pulses, which can, due to their extremely short flashing, provide us with very sharp images of moving atoms and electrons.
Nevertheless, some of the fastest processes still remained blurred. Those who want to explore the microcosm
In order to sharply capture motions of such particles during a reaction, one needs to work with"shutter speeds"in the range of femtoseconds
Scientists from the Laboratory for Attosecond Physics at LMU and MPQ have succeeded now in producing ultrashort electron pulses with a duration of only 28 femtoseconds.
If such electrons meet a molecule or atom, they are diffracted into specific directions due to their short wavelength.
the physicists applied their ultrashort electron pulses to a biomolecule in a diffraction experiment. It is planned to use those electron beams for pump-probe experiments:
an optical laser pulse is sent to the sample, initiating a response. Shortly afterwards the electron pulses produce a diffraction image of the structure at a sharp instant in time.
A large amount of such snapshots at varying delay times between the initiating laser pulses and the electron pulses then results in a film showing the atomic motion within the substance.
Thanks to the subatomic wavelength of the electrons, one therefore obtains a spatial image as well as the dynamics.
Altogether this results in a four-dimensional impression of molecules and their atomic motions during a reaction. ith our ultrashort electron pulses
we are now able to gain a much more detailed insight into processes happening within solids and molecules than before,
"Now the physicists aim to further reduce the duration of their electron pulses. The shorter the shutter speed becomes, the faster the motions
The aim of the scientists is to eventually observe even the much faster motions of electrons in light-driven processes o
which use photons instead of electrons to transport and manipulate information, offer many advantages compared to traditional electronic links found in today computers.
The team successfully suspended glass particles 400 nanometres across in a vacuum using an electric field,
where the position or energy of a particle exists in two or more states at the same time and entanglement,
where two particles share the same state (and change in tandem with each other) despite not touching.
We are trying to do the same with glass particles made up of billions of atoms,
During cavity cooling, a particle is suspended by a laser light field contained between two mirrors, which has a very carefully calibrated wavelength.
The laser light can hold the particle steady (a phenomenon known as optical tweezing) and draw motional energy out of it at the same time.
"Our solution was to combine the laser beam that cools the glass particle with an electric field
"The electric field also gently moves the glass particle around inside the laser beam, helping it lose temperature more effectively."
Since the particles currently used in quantum experiments are tiny, they have negligible mass and so barely interact with gravity.
two-dimensional particles embedded within a gel, stimulates bone growth through a complex signaling mechanism without the use of proteins known as growth factors,
Nanosilicate particles are embedded in a collagen-based hydrogel, forming a material that helps trigger bone formation within the body.
magnesium and lithium combined in tiny nanosilicate particles that are 100,000 times thinner than a sheet of paper.
Based on our strong preliminary studies, we predict that these highly biofunctional particles have immense potential to be used in biomedical applications
which strongly effects the propagation of light, in the same way that semiconductors control the flow of electrons.
Sabine van Rijt, CPC/ilbd, Helmholtz Zentrum Mnchen) Nanoparticles are extremely small particles that can be modified for a variety of uses in the medical field.
including irradiation with electrons and ions, but none of them worked. So far, the oxygen plasma approach worked the best,
#New study shows bacteria can use magnetic nanoparticles to create a'natural battery'(Nanowerk News) New research shows bacteria can use tiny magnetic particles to effectively create a'natural battery.'
"the bacteria can load electrons onto and discharge electrons from microscopic particles of magnetite. This discovery holds out the potential of using this mechanism to help clean up environmental pollution,
The flow of electrons is critical to the existence of all life and the fact that magnetite can be considered to be redox active opens up the possibility of bacteria being able to exist
phototrophic iron-oxidizing bacteria removed electrons from the magnetite, thereby discharging it. During the nighttime conditions, the iron-reducing bacteria took over
and were able to dump electrons back onto the magnetite and recharge it for the following cycle.
In principle, they are miniaturized extremely electron storage units. qdots can be produced using the same techniques as normal computer chips.
it is only necessary to miniaturize the structures on the chips until they hold just one single electron (in a conventional PC it is 10 to 100 electrons.
The electron stored in a qdot can take on states that are predicted by quantum theory. However, they are very short-lived:
a photon. Photons are wave packets that vibrate in a specific plane the direction of polarization.
The state of the qdots determines the direction of polarization of the photon.""We used the photon to excite an ion,
"explains Prof. Dr. Michael Khl from the Institute of Physics at the University of Bonn."
"Then we stored the direction of polarization of the photon"."Conscientious ions To do so, the researchers connected a thin glass fiber to the qdot.
They transported the photon via the fiber to the ion many meters away. The fiberoptic networks used in telecommunications operate very similarly.
To make the transfer of information as efficient as possible, they had trapped the ion between two mirrors.
The mirrors bounced the photon back and forth like a ping pong ball, until it was absorbed by the ion."
"In the process, we were able to measure the direction of polarization of the previously absorbed photon".
and more than 500 times faster than phosphorescence-lifetime-based two-photon microscopy (TPM. The results are published March 30 in Nature Methods advanced online publication("High-speed label-free functional photoacoustic microscopy of mouse brain in action".
#A quantum sensor for nanoscale electron transport The word defect doesnt usually have a good connotation--often indicating failure.
Graphic depiction of NV center sensors (red glowing spheres) used to probe electron motion in a conductor.
In this experiment, physicists harness the sensitivity of these isolated quantum systems to characterize electron motion.
At temperatures above absolute zero, the electrons inside of the silver layer (or any conductor) bounce around
Since electrons are charged particles, their motion results in fluctuating magnetic fields, which extend outside of the conductor.
which tells them about the electron behavior at a very small length scale. Like any good sensor, the NV centers are almost completely non-invasivetheir read-out with laser light does not disturb the sample they are sensing.
thus electrons travel dont travel very far--roughly 10 nanometers or less--before scattering off an obstacle.
and electrons can travel over 100 times farther. The electron movement, and corresponding magnetic field noise from the single silver crystal is a departure from so-called Ohmic predictions of the polycrystalline case,
and the team was able to explore both of these extremes non-invasively. These results demonstrate that single NV centers can be used to directly study electron behavior inside of a conductive material on the nanometer length scale.
Notably, this technique does not require electrical leads, applied voltages, or even physical contact with the sample of interest,
whether a proton gradient could induce water transport. We were surprised very to find that it could.
He says that osmotic agents often have to be at concentrations exceeding 100 millimolar to drive water movement in forward osmosis nanofiltration. f a proton gradient is used as the driving force instead,
the researchers created a spherical mass of particles, referred to as a nanoparticle carrier. They constructed the outer layer out of cationicor positively chargedsegments of the polymers.
But not only did the particles stay in place, they were also able to bind with the polymeric matrix
and potentially lead to applications in fields like nanomanufacturing and catalysis. We understand how particles work in 3-D,
the particles will bounce off each other and make a nice suspension, meaning you can do work with them.
Even when particles are able to stay at the interface they tend to clump together and form a skin that cant be pulled back apart into its constituent particles.
The teams technique for surmounting this problem hinged on decorating their gold nanoparticles with surfactant, or soap-like, ligands.
and the way they are attached to the central particle allows them to contort themselves so both sides are happy
when the particle is at an interface. This arrangement produces a flying saucer shape, with the ligands stretching out more at the interface than above or below.
These ligand bumpers keep the particles from clumping together. To get a picture of how the particles packed in their 2-D layer
the researchers dripped a particle-containing an oil droplet out of a pipette into water.
Over time, particles attached to the oil-water interface, at which point the researchers could change their packing density by sucking some of the oil back into the pipette.
By measuring the optical properties of the particles when overcrowding pushed some out, they could work backwards to the number of particles on the interface.
From there, they could determine some universal rules that govern the physics of such systems. This is a very beautiful system,
Stebe says. The ability to tune their packing means that we can now take everything we know about the equilibrium thermodynamics in two dimensions
and start to pose questions about particle layers. Do these particles behave like we think they should?
How can we manipulate them in the future e
#PI's New Motion Simulator'Shaker'Hexapod Based on Fast Linear Motors (Nanowerk News) PI (Physik Instrumente) LP, a leading manufacturer of precision motion
As the focused electron beam passed through the object it excited the crescent energetically, causing it to emit photons, a process known as cathodoluminescence.
Both the intensity and the wavelength of the emitted photons depended on which part of the object the electron beam excited,
Atre said. For instance, the gold shell at the base of the object emitted photons of shorter wavelengths than
when the beam passed near the gap at the tips of the crescent. By scanning the beam back and forth over the object,
the engineers created a 2-D image of these optical properties. Each pixel in this image also contained information about the wavelength of emitted photons across visible and near-infrared wavelengths.
This 2-D cathodoluminescence spectral imaging technique pioneered by the AMOLF team, revealed the characteristic ways in
The technique can be used to probe many systems in which light is emitted upon electron excitation."
"This is an electron wave in a phosphorus atom, distorted by a local electric field. Unlike conventional computers that store data on transistors and hard drives, quantum computers encode data in the quantum states of microscopic objects called qubits.
Associate professor Morello said the method works by distorting the shape of the electron cloud attached to the atom,
which the electron responds.""Therefore, we can selectively choose which qubit to operate. It's a bit like selecting which radio station we tune to,
Attempts to use polymers with benzene-like delocalised electron bonding alleviated issues around the thermal durability to a certain extent.
They used a fused ring system of molecules with benzene-like delocalised electron bonding so that the material would readily crystallise.
This interaction leads to a rapid creation of an electron distribution with an elevated electron temperature.
and rapidly converted into electron heat. Next, the electron heat is converted into a voltage at the interface of two graphene regions with different doping.
This photo-thermoelectric effect turns out to occur almost instantaneously, thus enabling the ultrafast conversion of absorbed light into electrical signals.
Such particles could be used to detect oil underground or aid removal in the case of oil spills.
and, with the help of STEVE, she/he can discover its interior components, such as nucleus and organelles, on any screen and in a limitless amount of colors.
which rely on the drift and diffusion of electrons and their holes through semiconducting material, memristor operation is based on ionic movement,
The ionic memory mechanism brings several advantages over purely electron-based memories which makes it very attractive for artificial neural network implementation,
he said. ons are also much heavier than electrons and do not tunnel easily, which permits aggressive scaling of memristors without sacrificing analog properties.
#Researchers create first whispering gallery for graphene electrons (Nanowerk News) An international research group led by scientists at the U s. Commerce departments National Institute of Standards
and Technology (NIST) has developed a technique for creating nanoscale whispering galleries for electrons in graphene. The development opens the way to building devices that focus
and amplify electrons just as lenses focus light and resonators (like the body of a guitar) amplify sound.
issue of Science("Creating and probing electron whispering-gallery modes in graphene")."An international research group led by scientists at NIST has developed a technique for creating nanoscale whispering galleries for electrons in graphene.
The researchers used the voltage from a scanning tunneling microscope (right) to push graphene electrons out of a nanoscale area to create the whispering gallery (represented by the protuberances on the left),
which is like a circular wall of mirrors to the electron. Image: Jon Wyrick, CNST/NIST) In some structures,
such as the dome in St pauls Cathedral in London, a person standing near a curved wall can hear the faintest sound made along any other part of that wall.
These whispering galleries are unlike anything you see in any other electron based system, and thats really exciting.
However, early studies of the behavior of electrons in graphene were hampered by defects in the material.
When moving electrons encounter a potential barrier in conventional semiconductors it takes an increase in energy for the electron to continue flowing.
As a result, they are reflected often, just as one would expect from a ball-like particle.
However, because electrons can sometimes behave like a wave, there is a calculable chance that they will ignore the barrier altogether,
a phenomenon called tunneling. Due to the light-like properties of graphene electrons, they can pass through unimpededno matter how high the barrierif they hit the barrier head on.
This tendency to tunnel makes it hard to steer electrons in graphene. Enter the graphene electron whispering gallery.
To create a whispering gallery in graphene the team first enriched the graphene with electrons from a conductive plate mounted below it.
With the graphene now crackling with electrons, the research team used the voltage from a scanning tunneling microscope (STM) to push some of them out of a nanoscale-sized area.
This created the whispering gallery, which is like a circular wall of mirrors to the electron.
An electron that hits the step head-on can tunnel straight through it, said NIST researcher Nikolai Zhitenev.
But if electrons hit it at an angle, their waves can be reflected and travel along the sides of the curved walls of the barrier until they began to interfere with one another,
creating a nanoscale electronic whispering gallery mode. The team can control the size and strength, i e.,
, the leakiness, of the electronic whispering gallery by varying the STM tips voltage. The probe not only creates whispering gallery modes,
Working at the Center for Nanoscale Materials (CNM) and the Advanced Photon Source (APS), two DOE Office of Science User Facilities located at Argonne,
when hit with an electron beam. Equally importantly they have discovered how and why it happens.
When floated on water the particles form a sheet; when the water evaporates, it leaves the sheet suspended over a hole.
When the electron beam hits the molecules on the surface it causes them to form an additional bond with their neighbors,
Argonne researchers are able to fold gold nanoparticle membranes in a specific direction using an electron beam
They envision zapping only a small part of the structure with the electron beam, designing the stresses to achieve particular bending patterns.
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