Search results for "trapping"
showing 6 items of 266 documents
Role of elastic and electronic interactions in trapping of hydrogen by impurities in transition metals
1985
The interplay between the lattice distortion and the electronic contributions to the trapping of migrating hydrogen isotopes by substitutional impurities is investigated. We use a comprehensive calculational scheme incorporating (i) the effective-medium theory for the electronic interaction, (ii) the lattice Green’s function for elastic coupling, and (iii) the hydrogen quantum motion. The calculations for Ti and Cr impurities in V host show that lattice strain effects dominate. Cr, which otherwise provides an electronic trap site, does not induce trapping when elastic effects are incorporated. The situation in the case of Ti is just the reverse. We find no isotope dependence of the binding …
Relationship between sleep disturbances and peripheral airway abnormalities in COPD patients
2017
Background: Individuals with COPD experience sleep disturbances due to the impact of symptoms on quality of sleep. Aim: To test the hypothesis that, in COPD, sleep disturbances are linked to peripheral airway abnormalities. Methods: An investigational study is being performed at the University of Palermo, Italy. The impact of breathing problems on quality of sleep during the previous week is measured with the COPD and Asthma Sleep Impact Scale (CASIS) questionnaire. Airway resistances by impulse oscillometry (IOS) assesses peripheral airway abnormalities. Lung function evaluation includes static and dynamic lung volume measurements. To rule out the risk of having obstructive sleep apnea, th…
Lung ventilation- and perfusion-weighted Fourier decomposition magnetic resonance imaging: In vivo validation with hyperpolarized3He and dynamic cont…
2012
The purpose of this work was to validate ventilation-weighted (VW) and perfusion-weighted (QW) Fourier decomposition (FD) magnetic resonance imaging (MRI) with hyperpolarized (3)He MRI and dynamic contrast-enhanced perfusion (DCE) MRI in a controlled animal experiment. Three healthy pigs were studied on 1.5-T MR scanner. For FD MRI, the VW and QW images were obtained by postprocessing of time-resolved lung image sets. DCE acquisitions were performed immediately after contrast agent injection. (3)He MRI data were acquired following the administration of hyperpolarized helium and nitrogen mixture. After baseline MR scans, pulmonary embolism was artificially produced. FD MRI and DCE MRI perfus…
Akute oder chronische Transplantat-Abstoßung? - HRCT des Thorax bei Patienten nach Lungentransplantation
2001
Purpose: Aim of the study was to evaluate the postoperative changes in patients with single (SLTX) or double lung transplantation (DLTX) with HRCT and to correlate those findings with the clinical diagnosis. Material and methods: 29 patients with SLTX (n = 14) or DLTX (n=15) were observed for more than 6 years after transplantation by HRCT (n =82). CT examinations were performed in inspiration and expiration (n=70) with a slice thickness of 1 mm and a feed of 10 mm. The image material was evaluated by 2 experienced radiologists in consensus. Criteria for acute rejection at HRCT were: ground glass opacities and focal air trapping in expiration. Criteria for chronic transplant rejection were:…
Effect of Er3+-doping on 65GeS2-25Ga2S3-10CsCl glass probed by annihilating positrons
2019
Abstract Effect of Er3+-doping resulting in pronounced mid-IR fluorescence functionality was examined first in chalcohalide 65GeS2-25Ga2S3-10CsCl glass using positron annihilation lifetime (PAL) spectroscopy. The detected PAL spectra were reconstructed from unconstrained x2-term analysis employing two-state simple trapping model for one kind of positron trapping free-volume defects, the parameterization being performed at the example of 65GeS2-25Ga2S3-10CsCl glass doped with 0.6 at. % of Er3+. The observed decrease in positron trapping rate was proved to be primary void-evolution process in this Er-activated glass, like in many other chalcogenide glasses affected by rare earth doping. The n…
Development of microfluidics for sorting of carbon nanotubes
2018
Sorting of carbon nanotubes by their chirality is the current bottleneck in the way to their broad employment based on their exceptional electronic and optical properties. Despite the extensive effort, there is no known method, which would result in really pure chirality ensembles. Previously reported sorting protocols result in enrichment rather than in sorting, alter electronic structure, and suffer from low yield. This is mostly due to the statistical approach, where the nanotubes with mixed chiralities are treated as a set. In this thesis, we propose a new sorting technique based on nanotube-by-nanotube compartmelization, characterization, and sorting in a continuously running droplet-b…