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,
moving through a conductive liquid medium called an electrolyte. Recharging the battery reverses the process,
and the ions travel back and stick onto the anode. But when they do, the ions don't attach evenly.
Instead, they form microscopic bumps that eventually grow into long branches after multiple recharging cycles. When these dendrites reach
the researchers used a computer to simulate the effect of heat on the individual lithium atoms that comprise a dendrite,
The simulations showed that increased temperatures triggered the atoms to move around in two ways. The atom at the tip of the pyramid can drop to lower levels.
Or an atom at a lower level can move and leave behind a vacant spot, which is filled then by another atom.
The atoms shuffle around, generating enough motion to topple the dendrite. By quantifying how much energy is needed to change the structure of the dendrite,
Aryanfar said, researchers can better understand its structural characteristics. And while many factors affect a battery's longevity at high temperatures--such as its tendency to discharge on its own
or the occurrence of other chemical reactions on the side--this new work shows that to revitalize a battery,
we have made two major advances--the ability to precisely control the brightness of light-emitting particles called quantum dots,
an assistant professor of bioengineering at Illinois."Previously light emission had an unknown correspondence with molecule number.
and calibrated to accurately count specific molecules. This will be particularly useful for understanding complex processes in neurons
""Fluorescent dyes have been used to label molecules in cells and tissues for nearly a century, and have molded our understanding of cellular structures and protein function.
These attributes obscure correlations between measured light intensity and concentrations of molecules,"stated Sung Jun Lim, a postdoctoral fellow and first author of the paper"
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."
Russian scientist Natalya Pugach from the Skobeltsyn Institute of Nuclear physics at the Lomonosov Moscow State university discovered this yet to be explained effect with her British colleagues,
which included Natalya Pugach from the Skobeltsyn Institute of Nuclear physics, studied the interactions between superconductivity
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.
and ferromagnetics may be used to control spins. Superconducting state is very responsive sensitive to magnetic fields: strong magnetic fields destroy it,
in magnetic layers storages the magnetic field tends to arrange spins in one direction, and the Cooper pair (BCS pair) in ordinary superconductors haves opposite spins."
"My colleagues experimented with devices called superconducting spin-valves. They look like a"sandwich, "made of nanolayers of ferromagnetic material, superconductor and other metals.
By changing the direction of magnetization it is possible to control the current in superconductor.
During the experiments scientists bombarded the experimental samples with muons (particles that resemble electrons, but are 200 times heavier) and analyzed their dissipation scattering.
The spin-valve consisted of two ferromagnetic cobalt layers, one superconductive niobium layer with thickness of approximately 150 atoms and a layer of gold.
But nevertheless this effect allows us to use the new method of manipulations with spins,
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
or high-energy reservoir of electrons. Lithium can do that, as the charge carrier whose ions migrate into the graphite
and create an electrical current. Aside from its ability to work well with a carbon anode
Right now, batteries based on this approach don't have performance that equals those of lithium-ion batteries,
"It's safe to say that the energy density of a potassium-ion battery may never exceed that of lithium-ion batteries,
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,
They used ion beam irradiation to modify the interface between the dots and the film to allow"imprinting"of the magnetic moments of the dots into the film.
Using neutron scattering at NIST Center for Neutron Research, they were able to resolve the magnetic profiles along the depth of the hybrid structure.
a process of aligning atoms inside a diamond so they create a signal detectable by an MRI SCANNER."
"By attaching hyperpolarised diamonds to molecules targeting cancers the technique can allow tracking of the molecules'movement in the body,
"This is a great example of how quantum physics research tackles real-world problems, in this case opening the way for us to image
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
#Single atom alloy platinum-copper catalysts cut costs, boost green technology: New generation of catalysts demonstrated for selective hydrogenation of butadiene Abstract:
A new generation of platinum-copper catalysts that require very low concentrations of platinum in the form of individual atoms to cleanly
isolated platinum atoms in much less costly copper surfaces can create a highly effective and cost-efficient catalyst for the selective hydrogenation of 1, 3 butadiene,
"We were excited to find that the platinum metal dissolved in copper, just like sugar in hot coffee, all the way down to single atoms.
We call such materials single atom alloys, "said Sykes. The Tufts chemists used a specialized low temperature scanning tunneling microscope to visualize the single platinum atoms and their interaction with hydrogen."
"We found that even at temperatures as low as minus 300 degrees F these platinum atoms were capable of splitting hydrogen molecules into atoms,
indicating that the platinum atoms would be very good at activating hydrogen for a chemical reaction,
"Sykes said. With that knowledge, Sykes and his fellow chemists turned to long-time Tufts collaborator Maria Flytzani-Stephanopoulos, Ph d.,the Robert and Marcy Haber Endowed Professor in Energy Sustainability at the School of engineering,
such as platinum-copper single atom alloy nanoparticles supported on an alumina substrate, and then tested them under industrial pressure and temperatures."
because clusters of platinum atoms have compared inferior selectivity with individual atoms.""In this case, less is said more
and manipulate atoms and molecules, and I wanted to use its unique capabilities to gain insight into industrially important chemical reactions.
In the early 2000s, Maria's group had pioneered the single-atom approach for metals anchored on oxide supports as the exclusive active sites for the water-gas shift reaction to upgrade hydrogen streams for fuel cell use.
Together we embarked on a new direction involving single atom alloys as catalysts for selective hydrogenation reactions.
"Sykes and Flytzani-Stephanopoulos have used this approach to design a variety of single atom alloy catalysts that have,
and properties of single atom alloy surfaces and then applied this knowledge to develop a working catalyst.
Armed with this knowledge, we are now ready to compare the stability of these single atom alloy catalysts to single atom catalysts supported on various oxide or carbon surfaces.
and the Ruhr Universität Bochum (RUB) have developed a new way to store information that uses ions to save data
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,
It consists of two metallic electrodes that are separated by a so-called solid ion conductor usually a transition metal oxide.
as well as ions within the layer between being displaced. The advantage is that cells that are constructed in this way are easy to produce
and can be reduced to almost the size of atoms. The scientists achieve a long storage time by setting the ion density in the cells precisely via the voltage applied."
"That was a big challenge, "said Mirko Hansen, doctoral candidate and lead author of the study from Kohlstedt's team,
"Electrons are roughly 1000 times lighter than ions and so they move much more easily under the influence of an external voltage.
whereby in our component, the ions are immovable for extremely low voltages, while the electrons remain mobile
and can be used to read the storage status."The trick: the researchers built an ion conductor,
which was only a few nanometres (a millionth of a millimetre) thin to utilise quantum-mechanical effects for the flow through the storage cells."
"The tunnel effect enables us to move electrons through the ultra-thin layer with very little energy,
ions are moved within the storage cell at voltages above one volt, 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. Rapid pattern recognition and a low energy consumption in connection with enormous parallel data processing would enable revolutionary computer architectures."
"This opens up a massive area for innovations in combination with terms like Industry 4. 0, in which autonomous robots work,
#Chalmers researchers extend the lifetime of atoms using a mirror: In an experiment researchers at Chalmers University of Technology have got an artificial atom to survive ten times longer than normal by positioning the atom in front of a mirror.
The findings were recently publish If one adds energy to an atom-one says that the atom is excited--it normally takes some time before the atom loses energy and returns to its original state.
This time is called the lifetime of the atom. Researchers at Chalmers University of Technology have placed an artificial atom at a specific distance in front of a short circuit that acts as a mirror.
By changing the distance to the mirror they can get the atom to live longer,
up to ten times as long as if the mirror had not been there. The artificial atom is actually a superconducting electrical circuit that the researchers make behave as an atom.
Just like a natural atom, you can charge it with energy; excite the atom; which it then emits in the form of light particles.
In this case, the light has a much lower frequency than ordinary light and in reality is microwaves."
"We have demonstrated how we can control the lifetime of an atom in a very simple way,
"says Per Delsing, Professor of Physics and leader of the research team.""We can vary the lifetime of the atom by changing the distance between the atom and the mirror.
If we place the atom at a certain distance from the mirror the atom's lifetime is extended by such a length that we are not even able to observe the atom.
Consequently, we can hide the atom in front of a mirror, "he continues. The experiment is a collaboration between experimental and theoretical physicists at Chalmers,
the latter have developed the theory for how the atom's lifetime varies depending on the distance to the mirror."
"The reason why the atom"dies",that is it returns to its original ground state, is that it sees the very small variations in the electromagnetic field which must exist due to quantum theory,
known as vacuum fluctuations,"says Göran Johansson, Professor of Theoretical and Applied Quantum physics and leader of the theory group.
When the atom is placed in front of the mirror it interacts with its mirror image, which changes the amount of vacuum fluctuations to
which the atom is exposed. The system that the Chalmers researchers succeeded in building is suited particularly well for measuring the vacuum fluctuations
which otherwise is a very difficult thing to measure r
#Production of Injectable Nanocomposite Paste in Iran Abstract: Iranian researchers from Materials and Energy Research center (MERC) succeeded in the production of a type of biocompatible nanocomposite with the ability to carry drugs,
which can be injected into damaged bones. After the completion of tests and being mass-produced, the product can be used in orthopedic surgeries to recover
and cure bones damaged due to tumors, cysts or fractures. The use of bone replacement in various forms has increased in recent years.
Injectable pastes are samples of the replacements used in tissue engineering. According to the researchers, the aim of the research was to prepare an injectable paste made of bioglass and sodium alginate polymer with biocompatibility properties.
Injectable pastes should be designed in a way that they can be injected by imposing acceptable force without phase separation between the powder and the liquid.
The weak point in the injectable systems is the inconsistency of pastes in contact with physiological liquids in the body,
which causes the paste to leave the area before the creation of the bone. The injected paste can stay in the implant area without moving
These starlike excitations are caused by a single magnetic atom put into the layer of superconducting material.
Physicists from France and Russia have discovered that the magnetic atoms in a two-dimensional layered superconductor create electronic disturbances that look like oscillating"nanostars".
and their colleagues from Paris-Saclay University studied the emergence of Yu-Shiba-Rusinov (YSR) states bound around single magnetic atoms embedded in a two-dimensional superconductor.
YSR states around single magnetic atoms of iron.""We have demonstrated that the use of two-dimensional superconductors instead of the three dimensional ones results in an increase in the spatial extension of YSR states for several dozen nanometres,
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.
For the last 20 years, scientists have been attempting to create quantum systems that will outperform traditional semiconductor-based computers, the development potential
One promising option is to use topologically protected electron states that are resistant to decoherence.
they are not negative ions, but rather special excitations in two-dimensional quantum systems in a magnetic field.
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
#Monitoring critical blood levels in real time in the ICU: EPFL has developed a miniaturized microfluidic device that will allow medical staff to monitor in real time levels of glucose,
metabolites (glucose, lactate and bilirubin) and ions (calcium and potassium), all of which indicate changes in the condition of intensive-care patients."
Building on this principle, up to 40 molecules could be monitored in real time. This advance will drastically reduce the number of machines cluttered around patients-an obvious practical advantage for the medical staff, not to mention the psychological boon for loved ones.
a postdoctoral researcher in Zia's lab. Cueff started with an emitter made of erbium ions,
This change in reflectivity, in turn, switches how nearby erbium ions emit light. As the VO2 changes phase, the erbium emissions go from being generated mostly by magnetic dipole transitions (the rotational torque push
metabolites (glucose, lactate and bilirubin) and ions (calcium and potassium), all of which indicate changes in the condition of intensive-care patients."
Building on this principle, up to 40 molecules could be monitored in real time. This advance will drastically reduce the number of machines cluttered around patients-an obvious practical advantage for the medical staff, not to mention the psychological boon for loved ones.
Theoretical physicists Wolfang Lechner, Philipp Hauke and Peter Zoller have proposed now a completely new approach. The trio, working at the University of Innsbruck and the IQOQI, suggest overcoming the challenges by detaching the logical qubit from the physical implementation.
These could be electrical fields when dealing with atoms and ions or magnetic fields in superconducting qubits."
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),
they form a ferromagnet--the type of magnet you might use on your refrigerator and that is used in the strip on your credit card.
Because spin has both a magnitude and a direction a spin-ordered phase is described by a vector.
Over the last several decades, physicists have developed sophisticated techniques to look for both of these types of phases.
But what if the electrons in a material are ordered not in one of those ways?
if the building block of the ordered phase was a pair of oppositely pointing spins--one pointing north
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
Long says that it should be possible to design MOF adsorbents of methane with even stronger gas binding sites and higher energy phase transitions for next generation ANG vehicles.
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.
This enables them to gain detailed insight into atomic motions in molecules. 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.
One femtosecond is a millionth of a billionth of a second. Such shutter speeds enable us to directly observe the truly fundamental motions of atoms and molecules in solids, similar to stroboscopy.
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:
molecules and atoms. For a long time, still images were provided, but for some years now scientists are making tremendous progress in short-pulse technology.
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
and its dynamics need a high-speed camera for atoms. In order to sharply capture motions of such particles during a reaction, one needs to work with"shutter speeds"in the range of femtoseconds
since this is the speed of reactions in molecules and solids. Commonly, femtosecond-short shutter speeds are provided by short-pulse laser technology,
but laser light is not able to spatially resolve atoms. 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.
This is six times shorter than ever before. The length of the matter wave is only about eight picometers;
one picometer is a trillionth of a meter. Due to this short wavelength, it is possible to visualize even single atoms in diffraction experiments.
If such electrons meet a molecule or atom, they are diffracted into specific directions due to their short wavelength.
This way they generate an interference pattern at the detector from which an atomic 3d-structure of the examined substance is reconstructed.
If the pulses are short enough, a sharp snapshot of the movement is the result.
Four-dimensional impression of molecules To test the new technique, 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,
"Dr. Peter Baum says. e are now able to record the fastest known atomic motions in four dimensions, namely in space and time".
"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
#Silk could be new'green'material for next-generation batteries Lithium-ion batteries have enabled many of today electronics, from portable gadgets to electric cars.
Chuanbao Cao and colleagues note that carbon is a key component in commercial Li-ion energy storage devices including batteries and supercapacitors.
showing diamine molecules (containing blue nitrogen atoms) attached to metal (manganese) atoms (green). Carbon dioxide molecules (grey carbon atoms with two red oxygen atoms) bind through a cooperative mechanism akin to a chain reaction along the pore surfaces.
Some H atoms (white) are omitted for clarity. Graphic by Thomas Mcdonald, Jarad Mason, Jeffrey Long/UC Berkeley) Though power plants are required not now to capture carbon dioxide from their emissions,
it will eventually be necessary in order to slow the pace of climate change caused by fossil-fuel burning.
"Long's team found that the diamines bind to the metal atoms of the MOF
At a sufficiently high pressure, one CO2 molecule binding to an amine helps other CO2 molecules bind next door,
charged ions burst through the holes. hen you extract and accelerate these ions, that momentum exchange propels the spacecraft in the opposite direction,
Brikner explains. Accion is on target to launch MAX-1 in July, and plans to start shipping the system to customers by the end of the year.
The team measured the emitted current of the released ions after applying certain levels of voltage.
In 2014, Accion entered the Global Founders Skills Accelerator (GFSA), a summer incubator in the Trust Center,
#3d printer for small molecules opens access to customized chemistry Howard hughes medical institute scientists have simplified the chemical synthesis of small molecules,
used a single automated process to synthesize 14 distinct classes of small molecules from a common set of building blocks.
Burke's team envisions expanding the approach to enable the production of thousands of potentially useful molecules with a single machine
which they describe as A d printerfor small molecules. Their work is described in the March 13, 2015, issue of the journal Science.
According to Burke, the highly customized approach that chemists have relied long on to synthesize small molecules is time consuming and inaccessible to most researchers. lot of great medicines have not been discovered yet because of this synthesis bottleneck,
and the small molecules would get synthesized and shipped, Burke says. e're not there yet,
but we now have an actionable roadmap toward on-demand small-molecule synthesis for non-specialists.
Nature produces an abundance of small molecules, and scientists have adapted already many of them for practical applications.
The vast majority of drugs are considered small molecules, as are many important biological research tools.
and solar cells also rely on small molecules. mall molecules have had already a big impact on the world,
Burke explains that chemists almost always develop a customized approach for manufacturing small molecules, designing a series of chemical reactions that,
yield the desired product. very time you make a molecule you have to develop a unique strategy.
Furthermore, it requires expertise. urrently you have to have a high degree of training in synthesis to make small molecules,
In his research, Burke has been exploring the potential of small molecules to treat disease. Plants
animals, and microbes manufacture many small molecules with protein-like functions, and with some precise chemical modifications, Burke suspects it may be possible to optimize some of these natural products to mimic the function of missing proteins enough to restore patients'health.
and test not just the small molecule found in nature, but also new versions with targeted modifications.
Making those molecules is a major barrier to drug discovery, Burke says. oing real atomistic modifications to transform nature's starting points into actual medicines is really,
Burke's team took cues from nature to streamline the synthesis of the molecules they were studying,
developing an approach that they have expanded now to make more general. ature makes most small molecules the same way,
That means small molecules are inherently modular. So when Burke's team analyzed the chemical structures of thousands of different natural products
The small-molecule synthesizer that Burke's team built takes these building blocks each with two chemical connectors that can be linked readily to the corresponding part on another building block
The team used the approach to synthesize 14 different small molecules, ranging from relatively straightforward linear structures to densely folded molecules featuring several chemical rings.
Burke's team has developed hundreds of these chemical building blocks and made them commercially available. ut it's not really about the numbers,
meaning the atom-by-atom modifications that researchers need to optimize these molecules into therapeutic compounds
and even the public to produce small molecules. hen you put the power to manufacture into the hands of everyone,
he says. 3d printer for molecules could allow us to harness all the creativity, innovation, and outside-the-box thinking that comes
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