sistem de dectie al armelor chimice , explozive, narcotice ,etc . Proiect de dezvoltare-cercetare al fortelor aeriene
au dezvoltat un senzor pe bază de grafen și un comutator care poate detecta poluarea dăunătoare a aerului în casă cu o consumare de energie foarte scăzută
A fost creat un senzor simplu dar eficient pentru monitorizarea ratei de respirație a persoanelor
Detectarea traseelor explozive;Evaluarea mobilității diferențiate (DMA) pentru detectarea urmelor;Sistem integrat pentru mobilitate și analiză de masă
pentru a crea textile inteligente care într-o zi ar putea vedea corturi din țesături generatoare de energie, pantofi de alergare la fel de ușor ca șosete și uniforme care detectează contaminarea chimică și nucleară
O echipa de cercetare pe la Institutul Shanghai de Fizică Tehnică (SITP), a proiectat un nanofire detector foto de înaltă performanță, cu structură gated-side prin combinarea materialului feroelectric și nanofire, și dispozitivul ca-fabricate pot fi folosite pentru a reduce întuneric de curent și de a crește sensibilitatea detectoarelor foto.
| Posted: Mar 31, 2016 | |
Ferroelectric localized field enhanced nanowire photodetectors(Nanowerk News) In recent years, one-dimensional semiconductor nanowires have been widely applied in photodetectors due to their excellent optoelectronic characteristics such as tunable light absorption, fast-response, and efficient light-to-current conversion. However, defect-induced intrinsic carriers and surface trapped charges at certain level result in appreciable dark currents, thus lowering the ratio of light to dark current (Ilight/Idark), limiting the detection performance of the photodetectors. |
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| Therefore, it is an urgent need to develop a unique device structure that can deplete the concentration of those defect/trap induced carriers, and thus increase signal-to-noise ratio and detectivity of nanowire based photodetectors. | |
| Now, a research team based at the Shanghai Institute of Technical Physics (SITP), has designed a high-performance nanowire photodetector with side-gated structure by combining ferroelectric materials and nanowires, and the as-fabricated device can be employed to reduce the dark current and increase the sensitivity of the photodetectors. | |
| The results have been published in the March 17, 2016 online edition of Nano Letters („When Nanowires Meet Ultrahigh Ferroelectric Field–High-Performance Full-Depleted Nanowire Photodetectors”). | |
| The researchers designed and fabricated a novel type of ferroelectric-enhanced side-gated single nanowire photodetectors for the first time. The intrinsic carriers in the nanowire channel can be fully depleted by the ultra-high electrostatic field from polarization of P(VDF-TrFE) ferroelectric polymer. In this scenario, the dark current is significantly reduced and thus the sensitivity of the photodetector is increased even when the gate voltage is removed. | |
| Utilizing this device structure, a typical single InP nanowire photodetector exhibits high photoconductive gain of 4.2 × 105, responsivity of 2.8 × 105 A W-1 and specific detectivity (D*) of 9.1 × 1015 Jones at λ = 830 nm. | |
| To further demonstrate the universality of the configuration, ferroelectric polymer side-gated single CdS nanowire photodetectors have been fabricated and demonstrated with ultra-high photoconductive gain of 1.2 × 107, responsivity of 5.2 × 106 A W-1 and D* up to 1.7 × 1018 Jones at λ = 520 nm. | |
| Additionally, the device also shows the advantages of fast-response, stability at room temperature, low power consumption and so on. | |
| These results demonstrate a new generic device structure design that can lead to controllable, full-depleted, high-performance and low power consumption nanowire photodetectors for a broad application. |
| Source: Shanghai Institute of Technical Physics |
Read more: Ferroelectric localized field enhanced nanowire photodetectors
Statele Unite au folosit spectrometria de mobilitate a ionilor pentru a detecta urme explozive pe tampoane.
susține un detector portabil prototip pe care compania îl produce, care poate detecta materiale explozive și gaze toxice
au acoperit fire de bumbac și poliester cu un nanoglue numit albumină serică bovină (BSA). Firele au fost apoi învelite în foi de oxid de grafen.Materialele cu acoperire cu oxid de grafen redus s-au dovedit a fi deosebit de sensibile la detectarea dioxidului de azot, un gaz poluant întâlnit frecvent în evacuarea vehiculului, care rezultă și din arderea combustibililor fosili
| Posted: Mar 15, 2016 | |
New graphene-coated e-fabrics detect noxious gases(Nanowerk News) The researchers, from the Electronics and Telecommunications Research Institute and Konkuk University in the Republic of Korea, coated cotton and polyester yarn with a nanoglue called bovine serum albumin (BSA). The yarns were then wrapped in graphene oxide sheets. |
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| Graphene is an incredibly strong one-atom-thick layer of carbon that is known for its excellent conductive properties of heat and electricity. The graphene sheets stuck very well to the nanoglue: so much so that further testing showed the fabrics retained their electrical conducting properties after 1,000 consecutive cycles of bending and straightening and ten washing tests with various chemical detergents. Finally, the graphene oxide yarns were exposed to a chemical reduction process, which involves the gaining of electrons. | |
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| The fiber sensor. (Image: Electronics and Telecommunications Research Institute) | |
| The reduced-graphene-oxide-coated materials were found to be particularly sensitive to detecting nitrogen dioxide, a pollutant gas commonly found in vehicle exhaust that also results from fossil fuel combustion. Prolonged exposure to nitrogen dioxide can be dangerous to human health, causing many respiratory-related illnesses. Exposure of these specially-treated fabrics to nitrogen dioxide led to a change in the electrical resistance of the reduced graphene oxide. | |
| The fabrics were so sensitive that 30 minutes of exposure to 0.25 parts per million of nitrogen dioxide (just under five times above the acceptable standard set by the U.S. Environmental Protection Agency) elicited a response. The fabrics were three times as sensitive to nitrogen dioxide in air compared to another reduced graphene oxide sensor previously prepared on a flat material. | |
| The new technology, according to the researchers, can be immediately adopted in related industries because the coating process is a simple one, making it suitable for mass production. It would allow outdoor wearers to receive relevant information about air quality. The materials could also be incorporated with air-purifying filters to act as “smart filters” that can both detect and filter harmful gas from air. | |
| “This sensor can bring a significant change to our daily life since it was developed with flexible and widely used fibres, unlike the gas sensors invariably developed with the existing solid substrates,” says Dr Hyung-Kun Lee, who led this research initiative. The study was published in Scientific Reports („ARTIKEL”). |
| Source: Electronics and Telecommunications Research Institute |
Deoarece trebuie să funcționeze în fiecare zi, trebuie să-și părăsească zona de confort și să se obișnuiască cu temperaturi, umiditate, ariditate și vibrații foarte variabile
Detectarea ultrasensibilă a particulelor nanometrice are aplicații în domenii importante, de la monitorizarea mediului până la analiza structurilor virale.Această metodă de detectare disipativă nu numai că oferă un nou mecanism fizic de detectare a microcavității, ci reprezintă, de asemenea, un pas semnificativ către senzorii optici practici în domeniile chimiei analitice, științei mediului și biologiei moleculare.
| Posted: Mar 07, 2016 | |
Novel whispering-gallery-type sensor for single nanoparticle detection(Nanowerk News) Ultrasensitive detection of nanoscale particles has applications in important fields ranges from environmental monitoring to analysis of viral structures. However, it remains extremely difficult due to ultralow polarizabilities of small-sized, low-index particles. |
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| A team led by Professor Xiao Yun-Feng at Peking University, collaborated with Yonsei University of Republic of Korea, demonstrated experimentally that the dissipative interaction in a high-Q optical microcavity allows the detection of single nanoparticles. | |
| This work has been published in the recent issue of Physical Review Applied („Detection of Single Nanoparticles Using the Dissipative Interaction in a High-Q Microcavity”). | |
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| Schematic drawing of on-chip microcavity sensors.The probelaser light is coupled into the whisperinggallery microcavity via a fiber taper. The cavity modes can be characterized by the transmission spectrum, shown as a resonance dip. When a single nanoparticle binds to the surface of the microcavity, the linewidth change of the cavity and the mode shift are simultaneously measured, representing the dissipative and reactive sensing method, respectively. | |
| Over the past few years, high-Q optical microcavities have shown great potential in sensing applications due to the strongly enhanced light-matter interaction therein. The conventional sensing mechanism, however, has to rely on the reactive interaction.The reactive sensing is limited by the polarizability of the particle, and will fail its sensing function when the real part of the polarizability approaches zero. In the publication, the authors pointed out that the dissipative interaction opens a channel of the cavity mode decay and results in the resonance linewidth change, which forms an effective sensing scheme even when the real part of analyte polarizability approaches zero, because the signal magnitude is determined by the absorption loss and side scattering of the particle. | |
| In the experiment, detection of single gold nanorodsis used to assess the sensing performance.“The gold nanorod of the size of 40 nm×16 nm is a perfect candidate to test the microcavity sensor for two reasons. One is that the polarizability of this nanoparticle can be tuned by varying the probe wavelength. The other is that the surface plasmon resonance of the particle of this dimension coincides with one of our probe wavelengths in the experiment, at which the real part of the polarizability become zero, most likely invalidating the reactive sensing method, but strengthening the dissipative one,” said Dr. YanyanZhi, the post-doctor and one of the co-first authors of this work. | |
| The researchers examined experimentally both the reactive and dissipative sensing methods, by monitoring the mode shift and the linewidth change of the high-Q cavity resonance, respectively. It is found that the reactive sensing signal cannot be recognized from the noises when the probe wavelength is on plasmonic resonance where the nanorod polarizability approaches zero, while the proposed dissipative sensing method still works well, which is consistent with the theoretical predictions.The anticipated detection limit can reach 13 nm×5 nm, which is about 12 times smaller volume than that can be detected by the reactive sensing method. | |
| This dissipative sensing method not only provides a new physical mechanism of microcavity sensing, but also represents a significant step towards practical optical sensors in areas of analytical chemistry, environmental science, and molecular biology. | |
| “Practically, it’s ready that both the mode shift and the linewidth change of the cavity mode can be simultaneously measured, and thus the common reactive and the proposed dissipative sensing methods are compatible to each other,” said Prof. Xiao, “The combination of those two sensing methods adds new dimensions to what can be measured using each of the two methods alone. The dissipative sensing method using a high-Q microcavityoffers a great platform for the detection of tiny single particles, such as vital virus, particles in the polluted air, lossy particles in the manufacturing process, and other nanoparticles under interest.” |
| Source: Peking University |
Read more: Novel whispering-gallery-type sensor for single nanoparticle detection
