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
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 |
dezvoltarea sistemelor de detectie chimica
detectare agenti chimici de lupta
programe senzori ;IARPA se așteaptă ca programul să aibă loc în două etape, care vor implica testarea unui set de senzori pe voluntari
detector gaze
detector de gaze toxice de lupta
Prin includerea de noi telescoape și facilități de radare bazate pe localizări diverse și prin revoluționarea motocicletelor procesăm diferite tipuri de date, anticipăm ameliorări imense în urmărirea obiectelor potențial periculoase și capacitatea noastră eficientă
laserul IR de spectru cu filament poate detecta orice tip de molecule
Dezvoltarea fotodetectoarelor a fost o chestiune de interes considerabil în ultimele decenii, deoarece aplicațiile lor sunt esențiale pentru multe domenii diferite, cum ar fi camerele, dispozitivele medicale, echipamentele de siguranță, dispozitivele de comunicații optice sau chiar instrumentele de măsurare, printre altele.
| Posted: Jun 17, 2016 | |
A new form of hybrid photodetectors with quantum dots and graphene(Nanowerk News) The development of photodetectors has been a matter of considerable interest in the past decades since their applications are essential to many different fields including cameras, medical devices, safety equipment, optical communication devices or even surveying instruments, among others. |
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| Many efforts have been focused towards optoelectronic research in trying to create low cost photodetectors with high sensitivity, high quantum efficiency, high gain and fast photoresponse. This is of paramount importance especially in the short wave infrared which currently is addressed by very expensive III-V InGaAs photodetectors. The development of two main classes of photodetectors, photodiodes and phototransistors, have partially been able to accomplish these goals because even though they both have many outstanding properties, none seem to fulfill all of these requirements. While photodiodes are much faster than phototransistors, phototransistors have a higher gain and do not require low noise preamplifiers for their use. | |
| To overcome these limitations, ICFO researchers Ivan Nikitskiy, Stijn Goossens, Dominik Kufer, Tania Lasanta, Gabriele Navickaite, led by ICREA professors at ICFO Frank Koppens and Gerasimos Konstantatos, have been able to develop a hybrid photodetector capable of attaining concomitantly better performance features in terms of speed, quantum efficiency and linear dynamic range, operating not only in the visible but also in the near infrared (NIR: 700-1400nm) and SWIR range (1400-3000nm). | |
| At the same time this technology is based upon materials that can be monolithically integrated with Si CMOS electronics as well as flexible electronic platforms. The results of this work have been recently published in Nature Communications („Integrating an electrically active colloidal quantum dot photodiode with a graphene phototransistor”). | |
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| This is a schematic of the device structure. (Image: ICFO) | |
| To be able to achieve this, the team of researchers developed a hybrid device by integrating an active colloidal quantum dot photodiode with a graphene phototransistor. By including an „active” quantum dot photodiode, they were able to increase charge collection in a highly absorbing thick QD film, which in turn increased the quantum efficiency as well as the photoresponse. The active quantum dot layer enabled a more effective charge collection by exploiting carrier drift towards the graphene layer instead of relying only on diffusion. The researchers then combined this scheme with a graphene transistor to register ultra-high-gains and record gain-bandwidth products, thanks to Graphene’s 2D character and remarkably high carrier mobility. | |
| The results obtained in this study have shown that this hybrid architecture does clearly demonstrate the potential of graphene and active quantum dot materials, opening new pathways for their integration in other optoelectronic materials in search for much higher performance and a broader spectrum of functionalities. |
| Source: ICFO |
a creat un nou laser revoluționar, cu bandă largă, reglabilă, care are implicații majore pentru detectarea drogurilor și a explozivilor.Robustul, tot laserul solid, poate fi reglat rapid pentru a emite în intervalul lungimii de undă care cuprinde regiunea critică a „amprentelor digitale” în care cele mai multe caracteristici moleculare sunt absorbite și identificate prin detectarea în infraroșu. În experimente, laserul și-a demonstrat capacitatea de a capta amprenta spectrală unică a gazelor.
| Posted: Jun 09, 2016 | |
Tunable lasers to improve infrared spectroscopy(Nanowerk News) A new development from Northwestern Engineering’s Manijeh Razeghi could be another tool for protecting our borders. |
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| Supported by the Department of Homeland Security, Razeghi’s lab has created a new, revolutionary, broad-band tunable infrared laser that has major implications for the detection of drugs and explosives. | |
| The robust, all solid-state laser can be rapidly tuned to emit in the wavelength range that encompasses the critical “fingerprint” region where most molecular features are absorbed and identified through infrared sensing. In experiments, the laser has demonstrated its ability to capture the unique spectral fingerprint of gases. | |
| “The only moving part in the entire system is the fan used to keep the laser cool,” said Manijeh Razeghi, Walter P. Murphy Professor of Electrical Engineering and Computer Science. “This is a major advantage over existing systems that require mechanical parts to achieve tuning, and we expect to demonstrate remarkable stability.” | |
| The initial, patent-pending results have been published in the June 8 issue of Nature Scientific Reports („Monolithically, widely tunable quantum cascade lasers based on a heterogeneous active region design”). The research and development of the laser system is the culmination of more than 18 years of quantum cascade laser development work at Northwestern’s Center for Quantum Devices. | |
| The laser has been integrated into a system that contains all of the laser driver electronics and tuning software necessary for integration into a spectroscopy system. It produces a stable, single-aperture spot less than 3 millimeters in diameter that is suitable for standoff detection and is capable of linear or random access scanning with stabilization times of less than 1 millisecond per wavelength. |
| Source: Northwestern University | |
