Search results for " frequency"
showing 10 items of 1398 documents
Double-quantum nutations in a two-level spin system
1986
The transient oscillatory behavior of the nonlinear response of a two-level electron-spin system is experimentally investigated in a sample of glassy silica with ${E}_{1}^{\mathcal{'}}$ centers (S=(1/2)) at microwave frequency at T=4.2 K. The transient regime, excited by an intense step-modulated radiation tuned to double-quantum (DQ) resonance, is monitored by revealing the second-harmonic (SH) wave radiated by the spins undergoing DQ transitions. Time- and frequency-domain results show that the emitted SH wave has two components: the former, which vanishes at the DQ resonance, exhibits an overdamped transient regime, the latter consists of damped oscillations at a frequency which depends …
Eye Cataract Simulation Using Polymer Dispersed Liquid Crystal Scattering Obstacles
2004
Polymer dispersed liquid crystals with electrically induced variations of light scattering extent similar to that of transparent PLZT ceramics are used for simulation of different development stages of eye cataract. Wavelength dependencies of scattering are determined in the visible spectral range, and human visual response looking through the scattering obstacle to the onset of various spatial frequency stimuli is determined psychophysically and electrophysiologically in order to find correlation between the scattering extent, visual acuity and visual evoked potential VEP chromatic characteristics.
Genome-wide detection of copy-number variations in local cattle breeds
2019
The aim of the present study was to identify copy-number variations (CNVs) in Cinisara (CIN) and Modicana (MOD) cattle breeds on the basis of signal intensity (logR ratio) and B allele frequency of each marker, using Illumina’s BovineSNP50K Genotyping BeadChip. The CNVs were detected with the PennCNV and SVS 8.7.0 software and were aggregated into CNV regions (CNVRs). PennCNV identified 487 CNVs in CIN that aggregated into 86 CNVRs, and 424 CNVs in MOD that aggregated into 81 CNVRs. SVS identified a total of 207 CNVs in CIN that aggregated into 39 CNVRs, and 181 CNVs in MOD that aggregated into 41 CNVRs. The CNVRs identified with the two softwares contained 29 common CNVRs in CIN and 17 co…
Evaluation of the primary stability in dental implants placed in low density bone with a new drilling technique, osseodensification: an in vitro study
2020
Background Primary stability is an important key determinant of implant osseointegration. We investigated approaches to improve primary implant stability using a new drilling technique termed osseodensification (OD), which was compared with the conventional under-drilling (UD) method utilized for low-density bones. Material and Methods We placed 55 conical internal connection implants in each group, in 30 low-density sections of pig tibia. The implants were placed using twist drill bits in both groups; groups Under Drilling (UD) and Osseodensification (OD) included bone sections subjected to conventional UD and OD drilling, respectively. Before placing the implants, we randomized the bone s…
Akadēmisko un vispārīgo vārdu biežuma salīdzinājums, izmantojot angļu valodas korpusus
2015
Bakalaura darba tēma veltīta korpusu lingvistikas jomas pētniecībai, lai veiktu biežāk lietoto vārdu salīdzināšanu akadēmiskajā un vispārējā angļu valodā ar teksta korpusu palīdzību. Izvēlētās tēmas aktualitāti nosaka valodniecības un moderno tehnoloģiju mijiedarbība, kā arī nepieciešamība izprast, kā tiek lietota un attīstās valoda. Bakalaura darba mērķis ir analizēt teorētisko literatūru par korpusu lingvistiku, kā arī atšķirības starp akadēmiskās un vispārējās angļu valodas pielietojumu. Pētījuma metodoloģija balstīta uz akadēmiskajā studijām un empīrisku pieeju pētījumam. Pētījuma dati iegūti, izmantojot atbilstošu programmatūru, kā arī analizējot biežāk sastopamos vārdus teksta korpuso…
Effects of electrical stimulation pattern on quadriceps isometric force and fatigue in individuals with spinal cord injury
2015
Introduction Variable frequency trains (VFT) or train combinations have been suggested as useful strategies to offset the rapid fatigue induced by constant frequency trains (CFT) during electrical stimulation. However, most studies have been of short duration with limited functional application in those with spinal cord injury (SCI). We therefore tested force and fatigue in response to VFT, CFT, and combined patterns in strength training-like conditions (6-s contractions). Methods Ten SCI individuals underwent either CFT or VFT patterns until target torque was no longer produced and then switched immediately to the other pattern. Results Target torque was reached more times when VFT was use…
Synthetic Inertia Impact on Inter-Area Oscillations of the Continental Europe Power System
2020
The overall kinetic energy reduction due to increasing share of converter-interfaced generation (CIG) has been investigated so far by several works for systems of different types and sizes. The so called synthetic inertia is one of the most common and reviewed solutions to the issue of system inertia reduction. The paper investigates the effects of synthetic inertia as frequency service provided by the CIG sources for the Continental Europe (CE) synchronous area using a detailed large scale dynamic model. The model - provided in the basic form by the System Protection & Dynamics (SP&D) group of the ENTSOE - is properly developed substituting a determined amount of synchronous machin…
Impact flavor compounds in cooked rice cultivars from the Camargue area (France)
2010
International audience; Rice from two scented (Aychade, Fidji) and one nonscented (Ruille) cultivars from Camargue area (France) together with one Asian scented rice (Thai) were cooked and volatile compounds were extracted by dichloromethane/pentane (1;2, v/v) solvent mixture. 40 odorous compounds were noticed during GC-O analysis of the organic extracts, amongst which oct-1-en-3-one and 2-acetyl-1-pyrroline were altmost constantly perceived. Hierarchical cluster analysis (HCA) of perceived odours enabled to distinguish the groups of rice cultivars. 60 compounds were identified and quantified by GC-MS. New odour-active components of cooked rice were detected for the first time including oct…
Impact flavor compounds in cooked rice cultivars from Camargue area (France)
2008
International audience; Efforts have been undertaken for the last decades to promote the production of scented rice cultivars in Camargue, a traditional rice cultivation area in the south of France. Volatile compounds of cooked rice from two scented Camargue rice cultivars (Aychade and Fidji) were analysed and compared to that of a marketed Asian scented rice one (Thai)(1). Additionally volatile analysis from a cooked rice of a non-scented cultivar (Ruille) grown in Camargue was performed. (...)
Polytetrafluoroethylene Films in Rigid Polyurethane Foams' Dielectric Permittivity Measurements with a One-Side Access Capacitive Sensor.
2021
As a non-metallic composite material, widely applied in industry, rigid polyurethane (PUR) foams require knowledge of their dielectric properties. In experimental determination of PUR foams’ dielectric properties protection of one-side capacitive sensor’s active area from adverse effects caused by the PUR foams’ test objects has to be ensured. In the given study, the impact of polytetrafluoroethylene (PTFE) films, thickness 0.20 mm and 0.04 mm, in covering or simulated coating the active area of one-side access capacitive sensor’ electrodes on the experimentally determined true dielectric permittivity spectra of rigid PUR foams is estimated. Penetration depth of the low frequency excitation…