Search results for "note"
showing 10 items of 10709 documents
Highly Sensitive Polarization Rotation Measurement through a High‐Order Vector Beam Generated by a Metasurface
2020
The precise determination of the polarization state of light is fundamental for a vast variety of applications in remote sensing, astronomy, optics and terahertz technology, to name just a few. Typically, polarization characterization is performed by using a combination of multiple optical devices such as beam splitters, polarizers, and waveplates. Moreover, to achieve high-precision, balanced photodetectors and lock-in amplifiers are employed, thus contributing to increasing system complexity. Here, a technique for polarization rotation measurements with a dynamic range of 180° and a sensitivity of about 10−2 degrees is realized using a properly designed metasurface. Such device generates …
Structure and dynamics in liquid bismuth and Bin clusters: A density functional study
2014
Density functional/molecular dynamics simulations with more than 500 atoms have been performed on liquid bismuth at 573, 773, 923, and 1023 K and on neutral Bi clusters with up to 14 atoms. There are similar structural patterns (coordination numbers, bond angles, and ring patterns) in the liquid and the clusters, with significant differences from the rhombohedral crystalline form. We study the details of the structure (structure factor, pair, and cavity distribution functions) and dynamical properties (vibration frequencies, diffusion constants, power spectra), and compare with experimental results where available. While the three short covalent bonds typical to pnictogens are characteristi…
Mālu minerālu un humusvielu kompozītmateriālu fizikāli ķīmiskās īpašības un pielietojums
2019
Bakalaura darba mērķis ir izstrādāt māla minerālu un humusvielu kompozītmateriālus un raksturot iegūtos produktus perspektīvai izmantošanai notekūdeņu attīrīšanā. Pētījuma ietvaros izvēlēti trīs rūpnieciski ražoti māla minerāli (kaolinīts, montmorilonīts un bentonīts), kas tika modificēti ar trīs veidu humusvielām (laboratorijas apstākļos ekstrahētām augstā purva kūdras humusvielām, lignīta humīnskābēm un kālija humātu, kas ir rūpnieciski ražoti). Humusvielu sorbcija uz māla minerāliem tika pētīta atkarībā no māla minerālu un humusvielu veida, humusvielu koncentrācijas, vides pH un sorbcijas laika. Iegūto produktu sorbcijas spēja tika pētīta, par modeļa piesārņotājvielu izmantojot hlorproma…
Televīzijas satura klasificēšana
2018
Darbā tiek pētīta televīzijas satura klasificēšana pēc raidījuma žanra. Tiek apskatīti citu autoru veiktie pētījumi televīzijas žanru klasifikācijas un saistīto video klasifikācijas problēmu risināšanā. Darba praktiskās daļas ietvaros ir izveidota televīzijas ierakstu datu kopa un veikta uz tās balstītu klasifikatoru izstrāde. Izveidotā ierakstu marķēšanas metode ļauj vienā stundā apstrādāt aptuveni 18 stundas ierakstu. Precīzākais uz konvolūciju neironu tīklu iezīmēm izstrādātais klasifikators uzrādīja 81,8% klasifikācijas precizitāti, pārspējot visaugstāko precizitāti uzrādījušo uz zema līmeņa iezīmēm balstīto klasifikatoru, kas pareizi atzīmēja 75,3% validācijas kopas datu. Uz konvolūcij…
Vietniekvārdu deiktiskās funkcijas sociālā tīmekļa vietnē „twitter.com”
2015
Maģistra darba temats ir „Vietniekvārdu deiktiskās funkcijas sociālā tīmekļa vietnē twitter.com”. Maģistra darba mērķis ir izpētīt teorētisko literatūru par vietniekvārdiem, deiksiem un analizēt vietniekvārdu deiktiskās funkcijas sociālā tīmekļa vietnē www.twitter.com. Pētāmais materiāls eksceprēts no ikdienas saziņas tviterī un no tvitera diskusijām par konkrētu tematu – 2015. gada Eirovīzijas dziesmu konkursu un 2015. gada Pasaules čempionātu hokejā. Maģistra darbā ir trīs nodaļas. Pirmajā nodaļā „Deiksi un to lietojums sociālā tīmekļa vietnē twitter.com” ir aprakstīts tvitera runas žanrs un konteksta nozīme deiksu analīzē. Otrajā nodaļā „Vietniekvārdu un deiksu raksturojums” ir apkopota …
Spin Pumping and Torque Statistics in the Quantum Noise Limit
2017
We analyze the statistics of charge and energy currents and spin torque in a metallic nanomagnet coupled to a large magnetic metal via a tunnel contact. We derive a Keldysh action for the tunnel barrier, describing the stochastic currents in the presence of a magnetization precessing with the rate Ω. In contrast to some earlier approaches, our result is valid for an arbitrary ratio of ℏΩ/kBT. We illustrate the use of the action by deriving spintronic fluctuation relations, the quantum limit of pumped current noise, and consider the fluctuations in two specific cases: the situation with a stable precession of magnetization driven by spin transfer torque, and the torque-induced switching betw…
The effect of carvacrol on enteric viruses.
2014
Carvacrol, a monoterpenic phenol, is said to have extensive antimicrobial activity in a wide range of food spoilage or pathogenic fungi, yeast and bacteria. The aim of this study was to assess its antiviral activity on norovirus surrogates, feline calicivirus (FCV), murine norovirus (MNV), and hepatitis A virus (HAV), as well as its potential in food applications. Initially, different concentrations of carvacrol (0.25, 0.5, 1%) were individually mixed with each virus at titers of ca. 6-7 log TCID50/ml and incubated 2h at 37°C. Carvacrol at 0.5% completely inactivated the two norovirus surrogates, whereas 1% concentration was required to achieve ca. 1 log reduction of HAV. In lettuce wash wa…
Internalization of novel non-viral vector TAT-streptavidin into human cells
2007
BMC Biotechnology, 7 (1)
Conception en technologie CMOS d'un Système de Vision dédié à l'Imagerie Rapide et aux Traitements d'Images
2008
Our work presented in this thesis focuses on the design, testing and implementation of monolithics CMOS image smart sensors : The principle, performance and limitations. The hardware implementation of a vision smart system is the central link. HISIC is High Speed Image Capture with processing at pixel level. An experimental platform for instrumentation and evaluation of retina operators was conducted during this thesis. After a state of the smart sensors and CMOS retinas, the second part is dedicated to the study and design of the pixel image sensor HISIC. Two circuits were realized in CMOS technology. The first identied a new type of photo-detector, and the second, to create a prototype em…
Highly sensitive olfactory biosensors for the detection of volatile organic compounds by surface plasmon resonance imaging
2018
International audience; Nowadays, monitoring of volatile organic compounds (VOCs) is very important in various domains. In this work, we aimed to develop sensitive olfactory biosensors using odorant binding proteins (OBPs) as sensing materials. Three rat OBP3 derivatives with customized binding properties were designed and immobilized on the same chip for the detection of VOCs in solution by surface plasmon resonance imaging (SPRi). We demonstrated that the proteins kept their binding properties after the immobilization under optimized conditions. The obtained olfactory biosensors exhibited very low limits of detection in both concentration (200pM of beta-ionone) and in molecular weight of …