Echipa de cercetare descoperă „materialul de cauciuc” care ar putea duce la vopsea rezistentă la zgârieturi pentru mașină ( Research team discovers ‘rubber material’ that could lead to scratch-proof paint for car )

, o echipa internationala de cercetatori a descoperit super-lubricitate in cateva straturi de grafen – un concept in care frecarea dispar sau aproape dispar. Experții au constatat, de asemenea, că câteva straturi de nitrurați de bor hexagonal (h-BN) sunt la fel de puternice ca diamantul, dar sunt mai flexibile, mai ieftine și mai ușoare.
Constatările, care au fost raportate în Nature Communications ( „Proprietățile mecanice ale nitriului de bor subțire subțire atomică și rolul interacțiunilor intermediare” ), arată că straturile h-BN formează cel mai puternic izolator subțire disponibil la nivel global și calitățile unice ale materialului să fie folosite pentru a crea dispozitive inteligente, flexibile și aproape incomode, precum și vopsea rezistentă la zgârieturi pentru mașini.

Posted: Sep 07, 2017
Research team discovers ‘rubber material’ that could lead to scratch-proof paint for car (Nanowerk News) Led by Dr Elton Santos from the University’s School of Mathematics and Physics, an international team of researchers have found superlubricity in a few layers of graphene – a concept where friction vanishes or very nearly vanishes. The experts also found that a few layers of hexagonal boron nitride (h-BN) are as strong as diamond but are more flexible, cheaper and lighter.
The findings, which have been reported in Nature Communications („Mechanical properties of atomically thin boron nitride and the role of interlayer interactions”), reveal that the h-BN layers form the strongest thin insulator available globally and the unique qualities of the material could be used to create flexible and almost unbreakable smart devices, as well as scratch-proof paint for cars.

Scratch proof paint for cars.
Dr Santos explains: „We have all at some point in life stepped on a slippery surface where we have to steady our balance so that we don’t fall. In most cases, liquid such as water or oil is the cause and this slippery state is what we describe as superlubricity – there is basically no friction on a surface.
„In graphene, this superlubricity state comes from atomic orbitals that compose carbon atoms. Normally, to generate friction some orbitals must overlap and heat, or some energy, must be released. Surprisingly, our research shows that graphene does not require this process, it just spontaneously slides on top of other layers but does not release heat. This means that graphene, which is 300 times stronger than steel, becomes mechanically weaker and can easily break.”
The research findings around the h-BN layers show that its mechanical properties are similar to diamond but are much cheaper, more flexible and lighter. It can easily be integrated in tiny electronic circuits or to reinforce structures as it is more robust against shocks or mechanical stress.
Dr Santos commented: „It has been a privilege to work with global researchers to predict and measure multilayer graphene and h-BN in an unprecedented way. It is nearly impossible at present to make major breakthroughs in science without working in collaboration. At Queen’s University we have advanced our knowledge of these layered materials and have made some major discoveries, which could help to tackle many global challenges within our society.
„Our key finding is that bilayer graphene develops a super-lubricity state where no heating is generated as the layers slide on top of each other. Just a few materials have these features and it looks like graphene has joined this exclusive club. During this process, we also discovered that h-BN, a common lubricant used in several automotive and industrial applications, developed a mechanical strength in a few layers. These are as strong as diamond, measured in terms of a quantity called Young modulus. This is a truly ground-breaking finding as even an insulator with thin layers could not keep its Young modulus at such high magnitudes.
„There are several possibilities for application of our discoveries which could have a positive impact in the real world. We are looking at a timeline of around five to ten years to transform the discoveries into real products but we could see benefits such as material reinforcement to mixture in solutions such as ink for paint, which would give further strength against corrosion and could potentially mean scratch-proof cars in future.
„This stretchy material could also be used in electronic devices and motor engines to make friction very low, as no heat is released.”
Dr Santos added: „In electronics, several companies are currently integrating h-BN in prototypes together with graphene for the creation of smart-devices such as iPads and Androids with unique features. These companies are also incorporating h-BN with polymers to give additional strength for novel mechanical applications such as aerospace, sports and civil engineering.
„We are currently looking for other combinations of 2D crystals which could be used for similar applications. So far, graphene seems the best candidate but there is still much to be explored within the library of layered materials. The future is bright for 2D materials because of the development, progress and research currently being performed worldwide.”

Source: Queen’s University Belfast

Conferința de știri despre apărare(Defense news Conference )

Iată tehnologia în care hub-urile de inovare ale DoD vor investi

Defense

Fotodiodele organice – detectori mai economici pentru regiunea NIR(Organic photodiodes – more economical detectors for the NIR region )

Senzor de imagine bazat pe fotodiodele organice pe siliciu, în aplicații tipice pentru camere. Context: Imagine NIR. (Imagine: Fraunhofer FEP, Fotograf: Jürgen Lösel)
Imaginile CMOS pe bază de siliciu convenționale sunt limitate la o regiune de lungime de undă restricționată din motive tehnologice fundamentale. Acestea sunt de obicei setate pe segmentul vizibil al spectrului. Dacă doriți să detectați lumina în infraroșu apropiat (NIR), cu toate acestea, soluții hibride, cum ar fi combinații de arsenid de iniu galiu (InGaAs) cu CMOS sunt, de obicei, recurs la.
Cu toate acestea, fabricarea acestor tipuri de soluții hibride este considerabil mai costisitoare și mai predispusă la defecte decât fabricarea utilizând procese standard CMOS. Aici fotodiodele organice oferă o alternativă. Straturile organice pot fi integrate pur și simplu la nivelul plachetelor și, prin urmare, sunt economice. În același timp, acestea pot avea, de asemenea, o sensibilitate ridicată în afara regiunii vizibile a lungimii de undă, în funcție de sistemul de materiale selectat

Posted: Sep 05, 2017
Organic photodiodes – more economical detectors for the NIR region (Nanowerk News) The Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP will be introducing a new generation of organic photodiodes on silicon substrates (OPD-on-silicon) during the SEMI European Imaging & Sensors Summit 2017, September 20-22 in Grenoble, France, at MINATEC, Booth 42.
Optical sensors are pervasive. Domestic life as well as the industrial environment are hard to imagine without them. For example, digital cameras using CMOS detectors have been indispensable vacation companions for many years, while in industry they serve as a simple and economical solution for automated image processing (such as in quality control applications, remote presence and position recognition and counting in conveyor systems, and object recognition in warehousing logistics). They can also be employed in medical engineering for diagnostic image processing. There are many future applications in the field of autonomous vehicles that are already foreseeable today.

Image sensor based on organic photodiodes on silicon in typical camera application. Background: NIR image. (Image: Fraunhofer FEP, Photographer: Jürgen Lösel)
Conventional silicon-based CMOS imagers are limited to a restricted wavelength region for fundamental technological reasons. They are usually set to the visible segment of the spectrum. If you want to detect light in the near-infrared (NIR), however, hybrid solutions such as combinations of indium gallium arsenide (InGaAs) with CMOS are usually resorted to.
Nevertheless, the manufacture of these kinds of hybrid solutions is considerably more costly and more prone to defects than fabrication using standard CMOS processes. This is where organic photodiodes offer an alternative. The organic layers can be integrated simply at wafer level and are therefore economical. Simultaneously, they also may have high sensitivity outside the visible wavelength region, depending on the system of materials selected.
The Fraunhofer FEP has extensive experience in integrating organic layers on CMOS wafers. Diverse OLED microdisplays (high-resolution, low power, embedded image sensors, …) as well as sensors for fingerprint, flow, and photoelectric sensing applications have already been developed and fabricated.
“We will be debuting an organic photodiode array with SVGA resolution at SEMI European Imaging & Sensors Summit 2017. That means 800 × 600 pixels available for detection applications”, explains Philipp Wartenberg, head of the IC and System Design department at Fraunhofer FEP. “We have demonstrated that it is fundamentally feasible to fabricate a high-resolution organic photodiode matrix at this order of magnitude. It is sensitive at wavelengths up to 1,000 nanometers. We are able to develop customer- and application-specific organic photodiodes with optimized properties for the concrete application through appropriate adaption of material.”
The demonstrated image sensors were fabricated completely at wafer-level and therefore already under near-production conditions. With its extended region of sensitivity, the imager can be employed over the entire bandwidth of conventional applications in industry, automobiles, and medicine. They could be used for quality control of foodstuffs, as fingerprint sensors, and in biomedical tests, for example.
The scientists are now making the new technology available to industrial partners in order to jointly develop and produce optimized organic photodiodes and arrays as image sensors for their respective applications.

Source: Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology

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Nanoimateriale de carbon mai sigure, prin design (Nanoparticles limit damage in spinal cord injury)

Nanowerk News ) Nanomaterialele de carbon (CNM) sunt o clasă de nanomateriale fabricate care pot fi utilizate pentru multe aplicații de mediu, inclusiv tratarea apei și detectarea și remedierea contaminanților. În timp ce sunt apreciați pentru abilitatea lor de a detecta, îndepărta sau degrada contaminanții din mediul înconjurător, CNM-urile nu dispar doar după ce sunt folosite.
„Ca orice substanță chimică care persistă în mediul înconjurător, există îngrijorări cu privire la impactul asupra organismelor și sistemelor care rezultă din pericolul inerent al materialului, al produselor sale de degradare și al potențialului său de a se bioacumula – sau se acumulează în corpurile vieții,

Posted: Sep 05, 2017
Nanoparticles limit damage in spinal cord injury (Nanowerk News) After a spinal cord injury, a significant amount of secondary nerve damage is caused by inflammation and internal scarring that inhibits the ability of the nervous system to repair itself.
A biodegradable nanoparticle injected after a spinal cord trauma prevented the inflammation and internal scarring that inhibits the repair process, reports a new Northwestern Medicine study.
As a result, mice with a spinal cord injury receiving the nanoparticle injection were able to walk better after the injury than those that didn’t receive it.
The treatment could potentially limit secondary damage to the spinal cord in humans after an injury, if administered a few hours after the accident in an emergency room or by paramedics in an ambulance.
“It’s not a cure. There is still the original damage, but we were able to prevent the secondary damage,” said co-senior author Dr. Jack Kessler, a professor of neurology at Northwestern University Feinberg School of Medicine and a Northwestern Medicine neurologist. “It’s an exciting potential treatment. We really believe this is something we’ll be able to take to the clinic.”
Further studies would need to confirm the safety of the injected nanoparticle, Kessler said, but he noted scientists haven’t seen any signs of toxicity so far.
The study was published in Neurobiology of Disease („Intravenous immune-modifying nanoparticles as a therapy for spinal cord injury in mice”).
The nanoparticles work by binding to the cells that cause the inflammation — inflammatory monocytes — and diverting them to the spleen. The particles are made of poly(lactic-co-glycolic) acid, a biocompatible substance already approved by the Food and Drug Administration (FDA) for use in re-absorbable sutures.
Developed in the lab of Northwestern scientist Stephen Miller, the particles also are FDA approved as an investigational drug for a new clinical trial in celiac disease.
“The study results suggest nanoparticle infusion could offer a novel and practical potential treatment for human spinal cord injury, a condition for which there are currently no effective treatments,” said Miller, the Judy Gugenheim Research Professor of Microbiology-Immunology at Feinberg.
After a spinal cord injury, blood cells that normally couldn’t enter the nervous system breech the protective blood brain barrier and flood the injury site. They release noxious chemicals, called inflammatory cytokines, which call in additional inflammatory blood cells. These cells further damage the central nervous system tissue by causing neuronal cell death and scar formation that blocks recovery from paralysis.
Two types of neurons die. One type — myelin — surrounds the nerve fibers and allows them to carry signals through the nervous system. If the myelin sheath is lost, the cells can no longer conduct signals. The other cells that die are axons, the long fibers extending from the neurons that carry signals from neuron to neuron.
“The new treatment is unusual because it is potentially immediately translatable to human beings,” Kessler said. “All we have to do is literally inject these beads into the blood stream. It doesn’t require surgery or any fancy intervention.”
The tiny beads also are very stable and can be kept in a syringe, Kessler noted. “An emergency medical technician at the site of an accident or somebody in an emergency room when someone is brought in can give this injection immediately,” he said.
Other researchers have tried techniques to block inflammatory monocytes from entering the nervous system after a spinal cord injury, but those methods blocked beneficial and harmful cells. The beneficial cells actually clean up the damage from the trauma and limit the scarring, so previous efforts resulted in only a modest improvement in scarring, cell death and repair.
The nanoparticle technology is being developed commercially by Cour Pharmaceuticals Development Co., which is working with Miller to bring this new approach to patients. Miller is a co-founder of Cour and a member of the scientific advisory board.
Miller also is a member of the Robert H. Lurie Comprehensive Cancer Center of Northwestern University.

Source: By Marla Paul, Northwestern University

Detectarea produselor alimentare contrafăcute(Detection of counterfeit food products )

Senzorul de pH fluorescent rasometric detectează modificările pH-ului în produsele lichide marcate atribuite contaminării bacteriene – o procedură comună în microbiologie

Detection

Prima analiză statică și dinamică a ceramicii tipărite sinterizate 3-D pentru aplicațiile de armură a corpului

Fabricarea tradițională a ceramicii utilizate pentru protecția împotriva impactului balistic este limitată de timpii lungi de plumb, de incapacitatea de a fabrica geometrii complexe și de componentele scumpe. Ceramica 3-D de tipărire oferă componente de inginerie la un timp de aproximativ 90% mai puțin decât fabricarea tradițională de ceramică. Schimbarea tipică poate fi zile, în loc de săptămâni, în funcție de complexitatea părții. Acest lucru permite un timp mai rapid de comercializare și permite mai multe iterații în timpul procesului de proiectare, rezultând un produs finit mai bun. În plus, piesele tipărite 3-D pot avea un grad mai mare de complexitate pentru reducerea greutății, economisind costul piesei, deoarece este necesar un material mai mic. Laboratorul de Cercetare al Armatei din S.U.A. (Adelphia, MD) a colaborat cu HotEnd Works LLC (Oberlin, Ohio) pentru a evalua fezabilitatea producerii armurii ceramice prin imprimare 3D. Acest raport examinează parametrii statici și cvasi-statici (inclusiv densitatea, duritatea și rezistența la fractură), performanța de penetrare semi-infinită și profilurile de fractură afectată a aluminei sinterizate tipărite 3-D în comparație cu performanța de bază a sinterizării tradiționale alumină

Prima analiză statică și dinamică

ARL

Adezivul solid se asamblează pe o cale către baterii mai sigure(Self-assembling solid crystals a path to safer, solid batteries )

Cercetatorii au identificat noi materiale solide care ar putea conduce la fabricarea de baterii litiu-ion netoxice,

Posted: Sep 04, 2017

Self-assembling solid crystals a path to safer, solid batteries

(Nanowerk News) Researchers have identified new solid materials that could lead to the manufacture of non-toxic lithium-ion batteries, according to a study recently published in the journal Science and Technology of Advanced Materials („Construction of nanostructures for selective lithium ion conduction using self-assembled molecular arrays in supramolecular solids”).When a specific organic compound is added to lithium salt, the molecules self-assemble to form channels through which lithium ions can move, creating an electric current.Batteries are made of two oppositely charged electrodes separated by a liquid, gel-like, or solid ‘electrolyte’ medium through which electrically charged atoms, or ions, move. In many cases, these electrolytes are toxic and flammable, so researchers have been looking for non-toxic alternatives.Makoto Moriya of Shizuoka University in Japan investigated molecular crystals for this purpose. To obtain the crystals he added an organic compound to lithium salt. The molecules self-assembled to form channels through which lithium ions moved, creating an electric current. Changing the crystals’ structures affected their ion-conducting functions.Ion conductivity in these materials was not as high as in organic liquids, inorganic ceramics or glass electrolytes. But it was comparable to polymer electrolytes, which have been targeted as potential solid electrolytes.Also, the amount of flammable organic substances in the molecular crystalline electrolytes was lower than in polymer electrolytes and in conventional liquid electrolytes, making them a potentially safer alternative.Moriya found it easy to control the crystal structure of these solid materials by making alterations to their molecules. This structural versatility could prove to be a powerful tool for dramatically improving ion conductivity in these materials.“These observations … could open the door to the design of new solid electrolytes and thus the development of new molecular devices,” Moriya concludes.

Source: National Institute for Materials Science

Grapefină pentru aplicații de detectare (Graphene woven fabrics for sensing application )

Grafenul a atras atenția extinsă datorită proprietăților sale excelente electrice, conductivității termice remarcabile, transparenței înalte, grosimii superioare și zonei mari specifice și, firește, a fost folosit ca material de detectare.
In ACS Applied Materials & Interfaces ( „simultană de înaltă sensibilitate de detectare a temperaturii și umidității cu Grafenul Țesături“ ), cercetatorii raport acum o temperatură și umiditate senzor flexibil (FTHS) din grafen țesături (GWFs) preparate prin depunere chimică din vapori (CVD) .
Senzorul a fost preparat printr-un proces de asamblare strat-cu-strat prietenos cu mediul. În comparație cu filmele de grafeni comune produse de CVD, GWF a fost compus din panglici de micrometru de intercalare cu cristale intercalate și au găuri dreptunghiulare, demonstrând o ultrasensibilitate cu un factor de gabarit de 500 până la deformare cu 2%.Rezultatele simulării și unele dispozitive raportate efectuate de GWF au demonstrat macrostructura și microstructura specială a GWF, care îi promite proprietăți unice și aplicații potențiale diversificate”, concluzioneaza autorii raportului. „Cu un design special, am folosit GWF-uri pentru a produce un senzor flexibil și bifuncțional. FTHS a arătat o sensibilitate ridicată la senzorii de temperatură, o performanță bună de detectare a umidității și o mică interferență reciprocă”.

Posted: Sep 04, 2017
Graphene woven fabrics for sensing application (Nanowerk News) Graphene has attracted extensive attention because of its excellent electrical properties, outstanding thermal conductivity, high transparency, ultrathin thickness, and large specific area, and naturally, it has been used as a sensing material.
In ACS Applied Materials & Interfaces („Simultaneous High Sensitivity Sensing of Temperature and Humidity with Graphene Woven Fabrics”), researchers now report a flexible temperature and humidity sensor (FTHS) from graphene woven fabrics (GWFs) prepared by chemical vapor deposition (CVD).
The sensor was prepared through an environmentally friendly layer-by-layer assembly process. Compared with the common graphene films produced by CVD, the GWF was composed of criss-crossed interlacing graphene micrometer ribbons and had rectangular holes, demonstrating ultra-sensitivity with a gauge factor of 500 to deformation within 2%.

(a) Schematic diagram of assembly steps of the FTHS. Inset: photograph of as-prepared FTHS. (b) Mechanism for temperature sensing. (c) Mechanism for humidity sensing. (© ACS) (click on image to enlarge)
The researchers found that the substrate, the length-width ratio of GWF, and the time of the oxygen plasma treatment greatly influenced the sensitivity of the temperature-sensing part.
„Simulation results and some reported devices made by GWF have proved the special macrostructure and microstructure of GWF, which promise it unique properties and diversified potential applications,” the authors conclude their report. „With a special design, we used GWFs to produce a flexible and bifunctional sensor. The FTHS showed high sensitivity in temperature sensing, good humidity sensing performance, and little mutual interference.”

By Michael Berger – Michael is author of two books by the Royal Society of Chemistry: N

Bateți căldura cu ajutorul filmelor cu nanoparticule(Beating the heat with nanoparticle films)

Nanoparticulele termocromice trec de la infraroșu transparent la reflector infraroșu atunci când se încălzesc, ceea ce va ajuta la menținerea clădirilor de birouri, a locuințelor și chiar a mașinilor răcoroase.Nanoparticule tunabile și reflexive.O echipă de cercetători, a petrecut câțiva ani încercând să dezvolte filme polimerice ușor de aplicat cu nanoparticule termochromice.

Beating

Supraviețuire prin supraviețuire HEL-STAR XO Lampă pentru căști de luptă multifuncțională / cascadă pentru corpul exoskeleton-cascadă, Lo-Pro / Hi-Vis (vizibilitate redusă / vizibilitate) Lampă vizibilă / IR pentru cocoș Ops(Core Survival HEL-STAR XO Exoskeleton-Body Helmet-Mounted, Multi-Function Combat/Tactical Helmet Light:Lo-Pro/Hi-Vis(Low-Profile/High-Visibility) Visible/IR Helmet Light for Airborne and Confined-Space Combat Ops)

am ridicat vizibilitatea laterală, deci este mai mult decât versiunile mai vechi

Stimp21

Trifecta dificilă a celulelor solare (The tricky trifecta of solar cells )

Aceste filme perovskite 2-D au prezentat anterior o stabilitate promițătoare, dar eficiența fotovoltaică relativ slabă (4,73%). Oamenii de știință atribuie eficienței reduse inhibării transportului de încărcătură în afara planului prin cationi organici, care acționează ca niște straturi izolatoare de distanțare între conducerea plăcilor anorganice.
O echipă de cercetători a depășit această eficiență slabă prin sintetizarea filmelor subțiri de calitate aproape cristalină unică, în care planurile cristalografice ale componentei perovskite anorganice sunt aliniate, în mod preferențial, în afara planului, în raport cu contactele electrice, facilitând astfel transportul încărcăturii.
Fotovoltaicii bazați pe aceste pelicule perovskite 2-D prezintă o eficiență de 12,52% și, atunci când sunt încapsulate, nu se degradează în condiții de lumină solară constantă și umiditate timp de săptămâni.

Posted: Aug 30, 2017
The tricky trifecta of solar cells (Nanowerk News) Layering thin sheets of two-dimensional (2-D) perovskite materials creates a promisingly stable solar cell. However, the cell is not as efficient as its thicker, less stable three-dimensional (3-D) counterpart.
Scientists overcame the inefficiency of 2-D perovskite solar cells without sacrificing stability. They did so by redesigning the cell so that the perovskite sheets were preferentially oriented perpendicular to the substrate, like books on a bookshelf (Science, „Extremely efficient internal exciton dissociation through edge states in layered 2D perovskites”).

Crystal structure of a three-layer Ruddlesden-Popper two-dimensional perovskite (top). Time-dependent (hours) power conversion efficiency (PCE) of encapsulated 2-D and 3-D perovskite planar solar cells under constant illumination (bottom). (Image: Mercouri Kanatzidis and Aditya Mohite)
These new materials may enable the “trifecta” of solar cell properties: inexpensive, stable and efficient. They are inexpensive because they are solution synthesized. They are stable on technologically relevant time scales. They are efficient with as high as 12.5 percent power conversion efficiency.
Three-dimensional (3-D) organic–inorganic perovskites have emerged as one of the most promising thin-film solar cell materials owing to a dramatic increase in their efficiencies in just a few short years, combined with their compatibility with inexpensive synthesis methods.
A major challenge, however, has been a property just as critical: environmental and photo stability under operating conditions. As one possible solution, scientists have been studying Ruddlesden-Popper phases: layered two-dimensional (2-D) counterparts to the 3-D perovskites.
These 2-D perovskite films have previously shown promising stability, but relatively poor photovoltaic efficiency (4.73 percent). The scientists attribute the low efficiency to inhibition of out-of-plane charge transport by organic cations, which act like insulating spacing layers between conducting inorganic slabs.
A research team overcame this poor efficiency by synthesizing thin films of near-single-crystalline quality, in which the crystallographic planes of the inorganic perovskite component are preferentially out-of-plane aligned with respect to the electrical contacts, thus facilitating charge transport.
Photovoltaics based on these 2-D perovskite films exhibit an efficiency of 12.52 percent and, when encapsulated, do not degrade under constant simulated solar illumination and humidity for weeks.

Source: Los Alamos National Laboratory