as researchers at the Max Planck Institute for the Science of Light (MPL) in Erlangen have demonstrated now("Flying particle sensors in hollow-core photonic crystal fibre").
The flying particle detects the quantities to be measured over long distances with a high spatial resolution, even under harsh conditions like those in an aggressive chemical substance or inside an oil pipeline.
In the beginning, the idea was to develop a radioactivity sensor for inside a nuclear power station says Tijmen Euser from the Max Planck Institute in Erlangen.
however, that radioactive radiation darkens the interior of conventional glass fibres so that light can no longer propagate therein,
making them unsuitable to measure radioactivity. The glass fibres which we owe particular thanks to for high rates of data transmission
As the air-filled cavity cannot be darkened by radioactive radiation the researchers see PCFS as an interesting alternative to conventional fibre-optic sensors in order to ultimately measure radioactivity as well.
The Erlangen-based physicists examined whether hollow-core photonic crystal fibres are suitable as sensors by initially using the fibres to measure electric fields, vibrations and temperatures.
which is generated by the impacts of the light on the particle. By setting the power of the two laser beams to different strengths,
the particle can now probe one parameter along the glass fibre at a time. Less light passes through the fibre in a strong electric field To measure the strength of an electric field,
as they also deflect the particle from the centre of the fibre. Electric fields and vibrations can be distinguished by the behaviour of beads carrying different levels of charge.
and the particle thus migrates faster through the channel of the fibre. To measure its speed,
Fluorescent beads as a sensor for radioactivity In their experiment the researchers used an oven to heat part of the fibre to temperatures of several hundred degrees Celsius.
With the aid of a rotating particle, whose rotational frequency depends on the viscosity of the air,
Next, we want to realize the radioactivity sensor, says Bykov. To do this, the researchers want to use fluorescent beads
which re-emit the radioactive radiation absorbed in the form of visible light. Information on the strength of the radioactivity at the location of the bead would then be provided by the changes in the intensity of the fluorescence.
Bykov sees great potential in the new technology. The spatial resolution would theoretically be limited only by the size of the particle.
Nanoparticles would then make it possible to measure with nanometre accuracy, i e. on the scale of viruses. The maximum length of the sensor fibre is currently around 400 metres,
An important, practical application of the new knowledge can be enzymatic digestion of useful molecules from wooden raw materials,
#Transition from 3 to 2 dimensions increases conduction Scientists from the MIPT Department of Molecular and Chemical Physics have described for the first time the behavior of electrons in a previously unstudied analogue of graphene, two-dimensional niobium telluride,
which can be described as"sheets"with a thickness of a few atoms, strongly differ from their three-dimensional analogues.
(Nature Physics,"Enhanced electron coherence in atomically thin Nb3site6"."In their structure, the crystals resemble sandwiches with a thickness of three atoms (around 4 angstroms:
a layer of tellurium, a layer of niobium mixed with silicon atoms and then another layer of tellurium.
This substance belongs to a class of materials known as dichalcogenides, which many scientists view as promising two-dimensional semiconductors.
The goal of the researchers was to investigate electron-phonon interaction changes in two-dimensional substances.
Quasi particles, quanta of crystal lattice oscillations, are called phonons. Physicists introduced the concept of phonons because it helped simplify the description of processes in crystals,
and tracking of electron-phonon interaction is fundamentally important for description of the different conducting properties in matter."
"We developed a theory that predicts that electron-phonon interaction is suppressed due to dimensional effects in two-dimensional material.
In other words, these materials obstruct the flow of electrons to a lesser extent, "says Pavel Sorokin, a co-author of the study, doctor of physical and mathematical sciences,
we managed to prove that changes in electron-phonon interaction occur specifically because of the two-dimensionality of the membrane,
#Using single molecules as sensors for ultrahigh-resolution 3d microscopy (Nanowerk News) Using a single molecule as a sensor,
The ultrahigh-resolution images provide information on the distribution of charges in the electron shells of single molecules and even atoms.
A single silver atom on a silver substrate (Ag (111)) under the scanning quantum dot microscope.
Their properties provide information, for instance, on the distribution of charges in atoms or molecules. For their measurements, the Jlich researchers used an atomic force microscope.
But the large size difference between the tip and the sample causes resolution difficulties if we were to imagine that a single atom was the same size as a head of a pin,
a single electron jumps from the tip of the microscope to the sensor molecule or back.
Forschungszentrum Jlich) Single molecule as a sensor In order to improve resolution and sensitivity, the scientists in Jlich attached a single molecule as a quantum dot to the tip of the microscope.
Quantum dots are tiny structures, measuring no more than a few nanometres across, which due to quantum confinement can only assume certain,
discrete states comparable to the energy level of a single atom. The molecule at the tip of the microscope functions like a beam balance,
which tilts to one side or the other. A shift in one direction or the other corresponds to the presence or absence of an additional electron
which either jumps from the tip to the molecule or does not. The"molecular"balance does not compare weights
but rather two electric fields that act on the mobile electron of the molecular sensor: the first is the field of a nanostructure being measured,
and the second is a field surrounding the tip of the microscope, which carries a voltage."
we can determine the field of the sample at the position of the molecule, "explains Dr. Christian Wagner,
comprising only 38 atoms, we can create a very sharp image of the electric field of the sample.
The scanning quantum dot micrograph of a PTCDA molecule reveals the negative partial charges at the ends of the molecule as well as the positive partial charges in the centre.
Simulated electric potential above a PTCDA molecule with molecular structure Right: Schematic of charge distribution in the PTCDA molecule.
Image: Forschungszentrum Jlich) Universally applicable A patent is pending for the method, which is particularly suitable for measuring rough surfaces, for example those of semiconductor structures for electronic devices or folded biomolecules."
essential prerequisites to carefully attach the single molecule to the tip of the microscope.""In principle, variations that would work at room temperature are conceivable,
Other forms of quantum dots could be used as a sensor in place of the molecule, such as those that can be realized with semiconductor materials:
The cloak is a thin Teflon sheet (light blue) embedded with many small, cylindrical ceramic particles (dark blue.
because they are made with metal particles, which absorb light. The researchers report that one of the keys to their cloak's design is the use of nonconductive materials called dielectrics,
which many small cylindrical ceramic particles were embedded, each with a different height depending on its position on the cloak."
"By changing the height of each dielectric particle, we were able to control the reflection of light at each point on the cloak,
We were able to demonstrate that a thin cloak designed with cylinder-shaped dielectric particles can help us significantly reduce the object's shadow.""
In a nanoscale world and that is our world we can control cellulose-based materials one atom at a time.
Two of Hinestrozas students created a hooded bodysuit embedded with insecticides using metal organic framework molecules,
We wanted to harness the power of these molecules to absorb gases and incorporate these MOFS into fibers,
"Meanwhile, we are already working on improving our molecules and developing procedures for testing them in live animals."
and environmentally benign method to combat bacteria by engineering nanoscale particles that add the antimicrobial potency of silver to a core of lignin,
"NC State engineer Orlin Velev and colleagues show that silver-ion infused lignin nanoparticles, which are coated with a charged polymer layer that helps them adhere to the target microbes,
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 s
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,
"Microcavity To produce the room-temperature condensate, the team of researchers from Polytechnique and Imperial College first created a device that makes it possible for polaritons-hybrid quasiparticles that are part light
The device is composed of a film of organic molecules 100 nanometres thick, confined between two nearly perfect mirrors.
Konstantinos Daskalakis, Imperial College London) Quantum objects visible to the naked eye Quantum mechanics tells us that objects exhibit not only particle-like behaviour,
with bosons, particles of a particular type that can be combined in large numbers in the same quantum state,
These are at the root of some of quantum physics'most fascinating phenomena, such as superfluidity and superconductivity.
A trap for half-light, half-matter quasiparticles Placing particles in the same state to obtain a condensate normally requires the temperature to be lowered to a level near absolute zero:
the team of researchers from Polytechnique and Imperial College first created a device that makes it possible for polaritons-hybrid quasiparticles that are part light
The device is composed of a film of organic molecules 100 nanometres thick confined between two nearly perfect mirrors.
"Our work demonstrates that it is possible to obtain comparable quantum behaviour using'impure'and disordered materials such as organic molecules.
Toward future polariton lasers and optical transistors In a condensate, the polaritons all behave the same way, like photons in a laser.
The research team foresees that the next major challenge in developing such applications will be to obtain a lower particle-condensation threshold
Fertile ground for studying fundamental questions According to Professor Maier, this research is also creating a platform to facilitate the study of fundamental questions in quantum mechanics."
"One fascinating aspect, for example, is the extraordinary transition between the state of non-condensed particles and the formation of a condensate.
then pumped in silicon atoms, which spontaneously crystallize on the wire. Rather than form a uniform shell,
the atoms grow into regularly spaced structures, similar to the droplets that appear when nanowires break down at high temperatures.
including silicon and germanium. In addition to being able to tune the distance between the lobes on nanowires,
The one-atom-thick carbon sheets could revolutionize the way electronic devices are manufactured and lead to faster transistors, cheaper solar cells, new types of sensors and more efficient bioelectric sensory devices.
The method is based on an ion implantation technique, a process in which ions are accelerated under an electrical field and smashed into a semiconductor.
The impacting ions change the physical, chemical or electrical properties of the semiconductor. In a paper published this week in the journal Applied Physics Letters("Wafer-scale synthesis of multi-layer graphene by high-temperature carbon ion implantation"),from AIP Publishing
the researchers describe their work, which takes graphene a step closer to commercial applications in silicon microelectronics.
Wafer-scale (4 inch in diameter) synthesis of multi-layer graphene using high-temperature carbon ion implantation on nickel/Sio2/silicon.
Image: J. Kim/Korea University, Korea)" For integrating graphene into advanced silicon microelectronics, large-area graphene free of wrinkles, tears and residues must be deposited on silicon wafers at low temperatures,
"Our work shows that the carbon ion implantation technique has great potential for the direct synthesis of wafer-scale graphene for integrated circuit technologies."
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."
"In silicon microelectronics, graphene is a potential contact electrode and an interconnection material linking semiconductor devices to form the desired electrical circuits,
"Kim's method relies on ion implantation, a microelectronics-compatible technique normally used to introduce impurities into semiconductors.
In the process, carbon ions were accelerated under an electrical field and bombarded onto a layered surface made of nickel, silicon dioxide and silicon at the temperature of 500 degrees Celsius.
Kim explained that the activation annealing temperature could be lowered by performing the ion implantation at an elevated temperature.
According to Kim, the ion implantation technique also offers finer control on the final structure of the product than other fabrication methods,
as the graphene layer thickness can be determined precisely by controlling the dose of carbon ion implantation.""Our synthesis method is controllable and scalable,
the jolt of energy can kick one of its electrons up to an excited state and create a charge distribution imbalance.
At the higher energy electron band, there's now an excess of negative charge due to the addition of an electron.
Meanwhile, at the lower energy electron band, there's an excess of positive charge (known as a"hole) "because an electron has left.
In this excited, unbalanced state, Tio2 can catalyze oxidation and reduction of materials around it. The excited electron will have a tendency to leave the Tio2 to reduce something nearby,
while the hole will help another substance to oxidize by accepting one of its electrons.
However pure Tio2 has a large bandgap--that is, it takes a great deal of energy to excite electrons from one level to another--and only displays photocatalytic properties under ultraviolet light.
Plus, the excited electron tends to quickly fall back down and recombine with the hole, giving the catalyst little time in its excited state to induce a reaction.
In order to turn Tio2 nanoparticles into a better photocatalyst, the researchers made several modifications. First, they added silver to the surface of the nanoparticles,
When light strikes Tio2 and excites one of its electrons the silver will pull that electron away
so that it can't fall back down into the hole. The hole can then more readily assist in an oxidation reaction.
which energetic electrons at the surface of a material vibrate at a specific frequency and enhance light absorption over a narrow range of wavelengths.
Like the silver, the addition of RGO helped the hole to persist by accepting excited electrons from Tio2.
maybe they could use our particles as well, Brandl says. hen we came up with the idea to use our particles to remove toxic chemicals, pollutants,
or hormones from water, because we saw that the particles aggregate once you irradiate them with UV LIGHT.
A trap for ater-fearingpollution The researchers synthesized polymers from polyethylene glycol, a widely used compound found in laxatives, toothpaste,
in a solution hydrophobic pollutant molecules move toward the hydrophobic nanoparticles, and adsorb onto their surface,
the stabilizing outer shell of the particles is shed, and now nrichedby the pollutants they form larger aggregates that can then be removed through filtration, sedimentation,
The fundamental breakthrough, according to the researchers, was confirming that small molecules do indeed adsorb passively onto the surface of nanoparticles. o the best of our knowledge,
it is the first time that the interactions of small molecules with preformed nanoparticles can be measured directly,
and molecules. he interactions we exploit to remove the pollutants are nonspecific, Brandl says. e can remove hormones, BPA,
we showed in a system that the adsorption of small molecules on the surface of the nanoparticles can be used for extraction of any kind,
Against such a background, recently neutron capture therapy (1) has been drawing attention. By irradiating the affected area with a pinpoint light beam, ultrasonic waves,
and thermal neutrons, which can be administered safely to living organisms, specific chemical compounds (neutron sensitizer elements) are activated
and kill the cancer cells. This therapy has a lower burden on patients. However, the technological development to deliver the neutron sensitizer molecules to cancer cells has been a great challenge.
A research team led by Professor Kazunori Kataoka, Department of Bioengineering, School of engineering, The University of Tokyo (concurrently serving as the Director of the Innovation Center of Nanomedicine,
or magnevist) broadly used as an MRI contrast agent to the affected area("Hybrid Calcium phosphate-Polymeric Micelles Incorporating Gadolinium Chelates for Imaging-Guided Gadolinium Neutron capture Tumor Therapy").
Moreover, when the Team applied the nanomachine to cancer neutron capture therapy, they confirmed a remarkable curative effect.
This nanomachine therapy enables an imaging-guided thermal neutron irradiation treatment; thus it can be expected to lead to a reliable cancer treatment with no missed cancer cells.
#Magnetic material unnecessary to create spin current (Nanowerk News) It doesn't happen often that a young scientist makes a significant and unexpected discovery,
but postdoctoral researcher Stephen Wu of the U s. Department of energy's Argonne National Laboratory just did exactly that("Paramagnetic Spin Seebeck Effect").
"What he found--that you don't need a magnetic material to create spin current from insulators--has important implications for the field of spintronics and the development of high-speed,
low-power electronics that use electron spin rather than charge to carry information. Typically when referring to electrical current,
an image of electrons moving through a metallic wire is conjured. Using the spin Seebeck effect (SSE),
it is possible to create a current of pure spin (a quantum property of electrons related to its magnetic moment) in magnetic insulators.
However, this work demonstrates that the SSE is limited not to magnetic insulators but also occurs in a class of materials known as paramagnets.
New ways of generating spin currents may be important for low-power high-speed spin based computing (spintronics),
which have been the centerpiece of all spin-based electronic devices up until this point. Image: Argonne National Laboratory) Wu's work upends prevailing ideas of how to generate a current of spins."
"This is a discovery in the true sense, "said Anand Bhattacharya, a physicist in Argonne's Materials science Division and the Center for Nanoscale Materials (a DOE Office of Science user facility),
"Spin is a quantum property of electrons that scientists often compare to a tiny bar magnet that points either"up"or"down."
One such method is to separate the flow of electron spin from the flow of electron current,
To create a current of spins in insulators, scientists have kept typically electrons stationary in a lattice made of an insulating ferromagnetic material,
such as yttrium iron garnet (YIG. When they apply a heat gradient across the material, the spins begin to"move"--that is,
information about the orientation of a spin is communicated from one point to another along the lattice,
much in the way a wave moves through water without actually transporting the water molecules anywhere.
Spin excitations known as magnons are thought to carry the current. Wu set out to build on previous work with spin currents,
expanding it to different materials using a new technique he'd developed. He worked on making devices a thousand times smaller than the typical systems used
giving him more control over the heat and allowing him to create larger thermal gradients in a smaller area."
in a paramagnet the spins aren't aligned as they are in a ferromagnet. They generate no magnetic field, produce no magnons,
and there appears to be no way for the spins to communicate with one another. But to everyone's surprise,
the spin current was stronger in the GGG than it was in the YIG.""The spins in the system were not talking to each other.
But we still found measurable spin current, "says Wu.""This effect shouldn't happen at all."
"The next step is to figure out why it does.""We don't know the way this works,
the objects that are moving the spin are not what we typically understand.""In the meantime, said Wu,
At its most basic level, your smart phone's battery is powering billions of transistors using electrons to flip on and off billions of times per second.
But if microchips could use photons instead of electrons to process and transmit data, computers could operate even faster.
the free electrons on its surface begin to oscillate together in a wave. These oscillations create their own light,
which reacts again with the free electrons. Energy trapped on the surface of the nanocube in this fashion is called a plasmon.
and a thin sheet of gold placed a mere 20 atoms away. This field interacts with quantum dots--spheres of semiconducting material just six nanometers wide--that are sandwiched in between the nanocube and the gold.
in turn, produce a directional, efficient emission of photons that can be turned on and off at more than 90 gigahertz."
lack of efficiency and inability to direct the photons, "said Gleb Akselrod, a postdoctoral research in Mikkelsen's laboratory."
"The group is now working to use the plasmonic structure to create a single photon source--a necessity for extremely secure quantum communications--by sandwiching a single quantum dot in the gap between the silver nanocube and gold foil.
which are atom-thick latticelike networks of carbon formed into cylinders. Graphene, made from single atom-thick layers of graphite,
was a suitable candidate due its electronic performance and mechanical strength. e knew in theory that
which the desired rate of molecule delivery could be tuned dynamically over time to achieve the optimal therapeutic outcome.
and electrons that propagate along a surface of a metal strip. At the end of the strip they are converted back to light once again.
and one oxygen atom) can be polymerized to form polycarbonates in reactions that use special catalysts.
Some of the amphiphilic polycarbonates made by this method are able to aggregate into particles or micelles in a self-organization process.
At the same time, effective washing for removing undesired molecules and debris guarantees the purity of the collected molecules.
These two factors constitute a successful strategy for epigenomic analysis with extremely high sensitivity"Lu said.
or more-then you need low energy dissipation, "said doctoral student Nathaniel Kinsey.""Otherwise, your material would heat up
Exposing the material to a pulsing laser light causes electrons to move from one energy level called the valence band to a higher energy level called the conduction band.
As the electrons move to the conduction band they leave behind"holes"in the valance band,
and eventually the electrons recombine with these holes. The switching speed of transistors is limited by how fast it takes conventional semiconductors such as silicon to complete this cycle of light to be absorbed,
excite electrons, produce holes and then recombine.""So what we would like to do is speed drastically this up,
patterns or elements that enable unprecedented control of light by harnessing clouds of electrons called surface plasmons.
The researchers"doped"zinc oxide with aluminum, meaning the zinc oxide is impregnated with aluminum atoms to alter the material's optical properties.
as shown by the reactions among small orange molecules. Since determining a surfaces wettability is trivially easy,
The water molecules break apart to form hydroxyl groups an atom of oxygen bound to an atom of hydrogen bonded to the materials surface.
The material comprised of germanium, antimony and tellurium in which data media store information may also be suitable as an extremely fast light switch for optical communication or data processing.
Electrons are diffracted differently in the crystalline structure of a compound of germanium, antimony and tellurium (GST) than in the amorphous one.
Itinerant binding electrons change the state Since the structural change would have to happen so rapidly,
As the images of the electron diffraction (grey rings) show, the crystalline structure is maintained here.
In order to understand what precisely happens here, it is helpful to take a look at the arrangement of the electrons in crystalline GST,
where individual electrons in addition to electron pairs bind the individual atoms together. These electrons are confined not to a bond between two atoms.
The electronic loners rather participate in multiple bonds simultaneously: they are bonded resonantly, as physicists say.
The resonantly bonded electrons dictate the optical properties of crystalline GST, however, they can be moved quite easily to conventionally bonded states.
He and his colleagues tracked the structural change with short bursts of electrons, which race through a crystal differently than through irregularly structured materials.
Since the researchers also sent the electrons after the exciting laser pulse with a different delay
they observed that the regular arrangement of the atoms is maintained longer than the electronic structure.
Since the realignment of the atoms causes stress and eventually fractures in the material, the atomic lattice of a substance cannot be rearranged infinitely often.
We want to investigate which states the electrons arrive at as they are excited and how the energy can flow away in sandwich structures,
This biomimetic membrane is composed of lipids--fat molecules --and protein-appended molecules that form water channels that transfer water at the rate of natural membranes,
and self-assembles into 2-dimensional structures with parallel channels.""Nature does things very efficiently
""We were surprised to see transport rates approaching the'holy grail'number of a billion water molecules per channel per second,
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