Talon CBRNe este dotat cu senzori CBRNE de înaltă tehnologie care oferă protecție maximă în misiunile CRBNE;sunt utilizate pe scară largă pentru dispozitive explozive improvizate, echipamente de distrugere a munițiilor explozive, de recunoaștere, chimice, biologice, radiologice, explozive nucleare, de securitate grele, misiuni de apărare și salvare
Materialele în cauză au fost denumite substanțe magnetoionice magnetice cu proprietăți care depind de aranjamentul ionilor, care sunt atomi cu încărcătură electrică. Designerii de memorii ale calculatorului le plac pentru că funcționează diferit decât dispozitivele electronice tradiționale, care depind de mișcarea electronilor pentru a reprezenta 1s și 0s. Dar electronii nu rămân în dispozitivele tradiționale când moare puterea.
| Posted: Jul 22, 2016 | |
Valuable fundamentals of a stacked, cracked Jack of all trades(Nanowerk News) There is a crack in everything, Leonard Cohen sang; that’s how the light gets in. Now a team led by scientists from the National Institute of Standards and Technology (NIST) has explored the properties of a promising class of materials with new capabilities that depend on those cracks. Their results (Nature Communications, „Beyond the Interface: Structural and Magnetic Depth Profiles of Magneto-Ionic Heterostructures Beyond the Interface”) could help open the way for practical applications from nonvolatile computer memory to quick-dimming windows. |
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| This magneto-ionic thin film, made primarily of aluminum oxide (red), gadolinium oxide (green) and cobalt (blue), allows oxygen ions to travel up and down through spaces between the layers when pushed by an electric field. Controlling the ions’ movement could be useful in computer memory storage and a host of other applications. The depth of the film depicted in this figure is on the order of 10 nanometers. (Image: D. Gilbert/NIST) | |
| The materials in question have been dubbed magneto-ionics—magnetic substances with properties that depend on the arrangement of ions, which are atoms with an electric charge. Computer memory designers like them because they work differently than traditional electronic devices, which depend on the movement of electrons to represent 1s and 0s. But electrons don’t stick around in traditional devices when the power dies. | |
| Enter magneto-ionics, which are formed of several extremely thin layers of oxygen-containing crystalline particles stacked atop one another. These particles stack together, but have small gaps between them—allowing oxygen ions to move around among the particles. If layers of particles are set down as a thin film upon a surface, the ions can be moved up and down through the layers using an electric field, changing how they behave, even making magnetic layers lose their magnetism. Controlling whether the layers are magnetic or not potentially allows information storage as 1s and 0s. And once an ion moves to a new place, it tends to stay there, even without electricity. | |
| Other nonvolatile memory technologies exist, most notably hard drives and flash memory, but they work relatively slowly, have relatively short lifetimes and cannot be scaled up past a certain point—hard drives, for example, can only have so many layers. Ionic technologies would also operate slowly, but would be more scalable. | |
| The appeal of these magneto-ionic films goes far beyond data storage though, said NIST physicist Dustin Gilbert, because of the wide range of properties that can be changed by moving the oxygen ions around. | |
| “Controlling oxygen distributions offers an opportunity to tune virtually every property of a material: magnetic, structural, optical, mechanical or chemical, to name a few,” Gilbert said. “So in a broad sense, you could imagine any number of devices where we apply a voltage and entirely change their functional behavior. One possibility would be a window coating that changes from opaque to mirrored or transparent, so that you could let in sunlight with the flick of a switch.” | |
| Despite their broader potential, most of the research that has been performed up to now on magneto-ionics has been on extremely thin films just a few atomic layers thick. The NIST team set out to explore the behavior of the substantially thicker films that could be crucial for commercial applications. | |
| Their research, performed using neutron reflectometry at the NIST Center for Neutron Research, turned up a number of findings useful for the industry’s future. Smaller particles, for example, tend to make for better magneto-ionic films, as there are more cracks through which the oxygen ions can travel. Also, changing the chemical makeup and crystal structure of the particles and layers changes the properties of the film dramatically, meaning that particle engineering will be a major concern for manufacturers. | |
| Films’ properties also change after the oxygen ions make a few round-trips through the layers, raising questions about how long a device based on magneto-ionics could last. | |
| “We need to be able to switch these things back and forth a huge number of times,” Gilbert said. “Their durability and speed is improving fast, but there’s still a way to go. By better understanding oxygen movement in these devices, our work should help a lot with that. We’ve cracked the underlying physics of these films’ magnetic properties, which should enlighten engineers about how they can use them.” |
| Source: NIST |
spectrometrele Raman portabile disponibile care pot fi luate în locuri îndepărtate pentru a detecta, de exemplu, viruși periculoși. Culorile fluorescente pe care le-au studiat vor face să fie rapid și ușor de observat prezența compușilor în celulele biologice.
| Posted: Jul 22, 2016 | |
Ultrasensitive sensor using N-doped graphene(Nanowerk News) A highly sensitive chemical sensor based on Raman spectroscopy and using nitrogen-doped graphene as a substrate was developed by an international team of researchers working at Penn State. In this case, doping refers to introducing nitrogen atoms into the carbon structure of graphene. This technique can detect trace amounts of molecules in a solution at very low concentrations, some 10,000 times more diluted than can be seen by the naked eye. |
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| Raman spectroscopy is a widely adopted identification technique used in chemistry, materials science and the pharmaceutical industry to detect the unique internal vibrations of various molecules. When a laser light irradiates crystals or molecules, it scatters and shifts colors. That scattered light can be detected in the form of a Raman spectrum, which serves almost as a fingerprint for every Raman-active irradiated system. | |
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| A model showing the charge transfer (e-) mechanism of Rhodamine B molecules (top) interacting with N-doped graphene (bottom sheet) when excited with different laser lines, which leads to ultrasensitive molecular sensor with N doped graphene. The white, blue and red balls represent carbon, nitrogen and oxygen atom respectively. (Image: Terrones Lab / Penn State) | |
| „Basically, different colors in the visible spectrum will be associated to different energies,” said Mauricio Terrones, professor of physics, chemistry and materials science at Penn State, who led the research. „Imagine each molecule has a particular light color emission, sometimes yellow, sometimes green. That color is associated with a discrete energy.” | |
| The team chose three types of fluorescent dye molecules for their experiments. Fluorescent dyes, which are frequently used as markers in biological experiments, are particularly hard to detect in Raman spectroscopy because the fluorescence tends to wash out the signal. However, when the dye is added to the graphene or N-doped graphene substrate, the photoluminescence – fluorescence – is quenched. | |
| On its own, the Raman signal is so weak that many methods have been used to enhance the signal. A recently developed enhancement technique uses pristine graphene as a substrate, which can enhance the Raman signal by several orders of magnitude. In a paper published online today (July 22) in the journal Science Advances („Ultrasensitive molecular sensor using N-doped graphene through enhanced Raman scattering”), Terrones and colleagues revealed that adding nitrogen atoms to the pristine graphene further enhances sensitivity and, importantly, they gave a theoretical explanation for how graphene and N-doped graphene cause the enhancement. | |
| „By controlling nitrogen doping we can shift the energy gap of the graphene, and the shift creates a resonance effect that significantly enhances the molecule’s vibrational Raman modes,” said lead author Simin Feng, a graduate student in Terrones’ group. | |
| „This is foundational research,” said Ana Laura Elias, a coauthor and research associate in Terrones’ lab. „It is hard to quantify the enhancement because it will be different for every material and color of light. But in some cases, we are going from zero to something we can detect for the first time. You can see a lot of features and study a lot of physics then. To me the most important aspect of this work is our understanding of the phenomenon. That will lead to improvements in the technique.” | |
| Terrones added, „We carried out extensive theoretical and experimental work. We came up with an explanation of why nitrogen-doped graphene works much better than regular graphene. I think it’s a breakthrough, because in our paper we explain the mechanism of detecting certain molecules.” | |
| Because of graphene’s chemical inertness and biocompatibility, the team expects that the new technique will be effective in detecting trace amounts of organic molecules. Elias is excited about the prospect of combining the technique with available portable Raman spectrometers that can be taken to remote places to detect, for instance, dangerous viruses. The fluorescent dyes they studied will make it fast and easy to see the presence of compounds inside biological cells. Because the technique is simple – just dip the graphene substrate into a solution for a short amount of time – it should be feasible to create an entire library of the Raman spectrum of specific molecules, Terrones said. |
| Source: Penn State |
Dioxidul de ceriu (ceria, CeO 2 ) este un material de suport utilizat pe scară largă pentru multe procese industriale importante; nanoparticulele metalice susținute pe ceria au prezentat activități înalte pentru aplicații, inclusiv convertoare catalitice auto, sinteză de alcool și pentru producția de hidrogen. Există două atribute cheie ale ceriei care o fac un excelent material de suport activ: capacitatea de stocare a oxigenului și capacitatea de eliberare și capacitatea sa de stabilizare a particulelor mici de metal în condiții de reacție.
| Posted: Jul 22, 2016 | |
Individual gold atoms can help generate clean fuel(Nanowerk News) A combined experimental and theoretical study comprising researchers from the Chemistry Department and LCN, along with groups in Argentina, China, Spain and Germany, has shed new light on the behaviour of individual gold atoms supported on defective thin cerium dioxide films – an important system for catalysis and the generation of clean hydrogen for fuel. |
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| Catalysis plays a vital role in our world; an estimated 80% of all chemical and materials are made via processes which involve catalysts, which are commonly a mixture of metals and oxides. The standard motif for these heterogeneous catalysts (where the catalysts are solid and the reactants are in the gas phase) is of a high surface area oxide support that is decorated with metal nanoparticles a few nanometres in diameter. | |
| Cerium dioxide (ceria, CeO2) is a widely used support material for many important industrial processes; metal nanoparticles supported on ceria have displayed high activities for applications including car catalytic converters, alcohol synthesis, and for hydrogen production. There are two key attributes of ceria which make it an excellent active support material: its oxygen storage and release ability, and its ability to stabilise small metal particles under reaction conditions. | |
| A recent system that has been the focus of much interest has been that of gold nanoparticles and single atoms with ceria, which has demonstrated high activity towards the water-gas-shift reaction, (CO + H2O –> CO2 + H2) a key stage in the generation of clean hydrogen for use in fuel cells. | |
| The nature of the active sites of these catalysts and the role that defects play are still relatively poorly understood; in order to study them in a systematic fashion, the researchers prepared model systems which can be characterised on the atomic scale with a scanning tunnelling microscope. | |
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| STM images of CeO2-x(111) ultrathin films before and after the deposition of Au single atoms at 300 K. The bright lattice is from the oxygen atoms at the surface – vacancies appear as dark spots. | |
| These model systems comprised well-ordered, epitaxial ceria films less than 2 nm thick, prepared on a metal single crystal, upon which single atoms and small clusters of gold were evaporated onto under ultra-high-vacuum (essential to prevent contamination of the surfaces). Oxygen vacancy defects – missing oxygen atoms in the top layer of the ceria – are relatively common at the surface and appear as dark spots in the STM images. By mapping the surface before and after the deposition of gold, it is possible to analyse the binding of the metal atoms, in particular there does not appear to be any preference for binding in the vacancy sites at 300 K. | |
| Publishing their results in Physical Review Letters („Diffusion Barriers Block Defect Occupation on Reduced CeO2(111)”), the researchers combined these experimental results with theoretical studies of the binding energies and diffusion rates across the surface. They showed that kinetic effects governed the behaviour of the gold atoms, prohibiting the expected occupation of the thermodynamically more stable oxygen vacancy sites. | |
| They also identified electron transfer between the gold atoms and the ceria, leading to a better understanding of the diffusion phenomena that occur at this scale, and demonstrated that the effect of individual surface defects may be more minor than is normally imagined. | |
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| „Spillover Reoxidation of Ceria Nanoparticles” (2016) and „Spectromicroscopy of a Model Water–Gas Shift Catalyst: Gold Nanoparticles Supported on Ceria” (2014) both in The Journal of Physical Chemistry |
| Source: London Centre for Nanotechnology |
materiale compozite care să conțină sute de straturi care sunt doar atomi grosime, dar care acoperă toată lățimea materialului . Descoperirea ar putea deschide posibilități largi de proiectare a compozitelor noi și ușor de fabricat pentru dispozitive optice, sisteme electronice și materiale de înaltă tehnologie.Echipa a găsit, de asemenea, o modalitate de a face fibre structurate din grafen, care să permită crearea de fire și țesături cu funcții electronice încorporate, precum și o altă clasă de compozite. Metoda folosește un mecanism de forfecare, oarecum asemănător cu un dispozitiv de tăiere a brânzei, pentru a îndepărta straturile de grafen într-un mod care le face să se rostogolească într-o formă asemănătoare scroll-ului, cunoscută din punct de vedere tehnic ca o spirală arhimedeană.O caracteristică neașteptată a noilor compozite stratificate, spune Strano, este că straturile de grafeni, care sunt extrem de conductive din punct de vedere electric, își mențin continuitatea pe tot parcursul eșantionului lor compozit fără a se scurtcircuita la straturile adiacente
| Posted: Jul 21, 2016 | |
Borrowing from pastry chefs, engineers create nanolayered composites(Nanowerk News) Adapting an old trick used for centuries by both metalsmiths and pastry makers, a team of researchers at MIT has found a way to efficiently create composite materials containing hundreds of layers that are just atoms thick but span the full width of the material. The discovery could open up wide-ranging possibilities for designing new, easy-to-manufacture composites for optical devices, electronic systems, and high-tech materials. |
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| The work is described this week in a paper in Science („Layered and scrolled nanocomposites with aligned semi-infinite graphene inclusions at the platelet limit”) by Michael Strano, the Carbon P. Dubbs Professor in Chemical Engineering; postdoc Pingwei Liu; and 11 other MIT students, postdocs, and professors. | |
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| CThe process of making a stack of parallel sheets of graphene starts with a chemical vapor deposition process (I) to make a graphene sheet with a polymer coating; these layers are then stacked (II), folded and cut (III) and stacked again and pressed, multiplying the number of layers. The team used a related method the team to produce scroll-shaped fibers. (Image: Courtesy of the researchers) (click on image to enlarge) | |
| Materials such as graphene, a two-dimensional form of pure carbon, and carbon nanotubes, tiny cylinders that are essentially rolled-up graphene, are „some of the strongest, hardest materials we have available,” says Strano, because their atoms are held together entirely by carbon-carbon bonds, which are „the strongest nature gives us” for chemical bonds to work with. So, researchers have been searching for ways of using these nanomaterials to add great strength to composite materials, much the way steel bars are used to reinforce concrete. | |
| The biggest obstacle has been finding ways to embed these materials within a matrix of another material in an orderly way. These tiny sheets and tubes have a strong tendency to clump together, so just stirring them into a batch of liquid resin before it sets doesn’t work at all. The MIT team’s insight was in finding a way to create large numbers of layers, stacked in a perfectly orderly way, without having to stack each layer individually. | |
| Although the process is more complex than it sounds, at the heart of it is a technique similar to that used to make ultrastrong steel sword blades, as well as the puff pastry that’s in baklava and napoleons. A layer of material – be it steel, dough, or graphene – is spread out flat. Then, the material is doubled over on itself, pounded or rolled out, and then doubled over again, and again, and again. | |
| With each fold, the number of layers doubles, thus producing an exponential increase in the layering. Just 20 simple folds would produce more than a million perfectly aligned layers. | |
| Now, it doesn’t work out exactly that way on the nanoscale. In this research, rather than folding the material, the team cut the whole block – itself consisting of alternating layers of graphene and the composite material – into quarters, and then slid one quarter on top of another, quadrupling the number of layers, and then repeating the process. But the result was the same: a uniform stack of layers, quickly produced, and already embedded in the matrix material, in this case polycarbonate, to form a composite. | |
| In their proof-of-concept tests, the MIT team produced composites with up to 320 layers of graphene embedded in them. They were able to demonstrate that even though the total amount of the graphene added to the material was minuscule – less than 1/10 of a percent by weight – it led to a clear-cut improvement in overall strength. | |
| „The graphene has an effectively infinite aspect ratio,” Strano says, since it is infinitesimally thin yet can span sizes large enough to be seen and handled. „It can span two dimensions of the material,” even though it is only nanometers thick. Graphene and a handful of other known 2-D materials are „the only known materials that can do that,” he says. | |
| The team also found a way to make structured fibers from graphene, potentially enabling the creation of yarns and fabrics with embedded electronic functions, as well as yet another class of composites. The method uses a shearing mechanism, somewhat like a cheese slicer, to peel off layers of graphene in a way that causes them to roll up into a scroll-like shape, technically known as an Archimedean spiral. | |
| That could overcome one of the biggest drawbacks of graphene and nanotubes, in terms of their ability to be woven into long fibers: their extreme slipperiness. Because they are so perfectly smooth, strands slip past each other instead of sticking together in a bundle. And the new scrolled strands not only overcome that problem, they are also extremely stretchy, unlike other super-strong materials such as Kevlar. That means they might lend themselves to being woven into protective materials that could „give” without breaking. | |
| One unexpected feature of the new layered composites, Strano says, is that the graphene layers, which are extremely electrically conductive, maintain their continuity all the way across their composite sample without any short-circuiting to the adjacent layers. So, for example, simply inserting an electrical probe into the stack to a certain precise depth would make it possible to uniquely „address” any one of the hundreds of layers. This could ultimately lead to new kinds of complex multilayered electronics, he says. |
| Source: By David L. Chandler, MIT |
Noile materiale funcționale sunt oxizi, inclusiv câteva tipuri de materiale care, până în prezent, nu au putut fi integrate pe așchii de siliciu: materiale multiferoice, care au proprietăți feroelectrice și feromagnetice; izolații topologici, care acționează ca izolatori în vrac, dar au proprietăți conductive pe suprafața lor; și noi materiale feroelectrice. Aceste materiale sunt considerate a avea promisiuni pentru aplicații, inclusiv senzori, memorie nevolatilă de calculator și sisteme microelectromecanice, care sunt mai bine cunoscute sub numele de MEMS.
| Posted: Jul 21, 2016 | |
Integration of novel materials with silicon chips makes new ‘smart’ devices possible(Nanowerk News) Researchers from North Carolina State University and the U.S. Army Research Office have developed a way to integrate novel functional materials onto a computer chip, allowing the creation of new smart devices and systems. |
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| The novel functional materials are oxides, including several types of materials that, until now, could not be integrated onto silicon chips: multiferroic materials, which have both ferroelectric and ferromagnetic properties; topological insulators, which act as insulators in bulk but have conductive properties on their surface; and novel ferroelectric materials. These materials are thought to hold promise for applications including sensors, non-volatile computer memory and microelectromechanical systems, which are better known as MEMS. | |
| „These novel oxides are normally grown on materials that are not compatible with computing devices,” says Jay Narayan, the John C. Fan Distinguished Chair Professor of Materials Science and Engineering at NC State and co-author of a paper describing the work (Applied Physics Reviews, „Multifunctional epitaxial systems on silicon substrates”). „We are now able to integrate these materials onto a silicon chip, allowing us to incorporate their functions into electronic devices.” | |
| The approach developed by the researchers allows them to integrate the materials onto two platforms, both of which are compatible with silicon: a titanium nitride platform, for use with nitride-based electronics; and yttria-stabilized zirconia, for use with oxide-based electronics. | |
| Specifically, the researchers developed a suite of thin films that serve as a buffer, connecting the silicon chip to the relevant novel materials. The exact combination of thin films varies, depending on which novel materials are being used. | |
| For example, if using multiferroic materials, researchers use a combination of four different thin films: titanium nitride, magnesium oxide, strontium oxide and lanthanum strontium manganese oxide. But for topological insulators, they would use a combination of only two thin films: magnesium oxide and titanium nitride. | |
| These thin film buffers align with the planes of the crystalline structure in the novel oxide materials, as well as with the planes of the underlying substrate – effectively serving as a communicating layer between the materials. | |
| This approach, called thin film epitaxy, is based on the concept of domain-matching epitaxy, and was first proposed by Narayan in a 2003 paper („Domain epitaxy: A unified paradigm for thin film growth”). | |
| „Integrating these novel materials onto silicon chips makes many things possible,” Narayan says. „For example, this allows us to sense or collect data; to manipulate that data; and to calculate a response – all on one compact chip. This makes for faster, more efficient, lighter devices.” | |
| Another possible application, Narayan says, is the creation of LEDs on silicon chips, to make „smart lights.” Currently, LEDs are made using sapphire substrates, which aren’t directly compatible with computing devices. | |
| „We’ve already patented this integration technology, and are currently looking for industry partners to license it,” Narayan says. |
| Source: By Matt Shipman, North Carolina State University |
Titanul este materialul principal pentru articulațiile artificiale de genunchi și șold, deoarece este puternic, rezistent la uzură și netoxic, însă o descoperire neașteptată de către fizicienii Universității Rice arată că standardul de aur pentru articulațiile artificiale poate fi îmbunătățit prin adăugarea unor aur real
Capacitățile CBRN de a defecta amenințările și de a proteja respondenții și populațiile civile
dezvoltarea sistemelor de detectie chimica
au făcut ca un obiect să dispară prin utilizarea unui material compozit cu pericole de dimensiuni nanometrice care pot spori proprietățile specifice pe suprafața obiectului;While the research might not lead to the invisibility cloak made famous JK novels quite yet, this practical demonstration could result in a step-change in how antennas are tethered to their platform
Programul POSYDON încearcă să creeze o rețea de balize acustice subacvatice care acționează ca sateliții GPS – difuzând o serie de date codificate în unde sonore pe care ambarcațiunea subacvatică le poate folosi pentru a obține o reperetie la locația lor
