Raman study of insulating and conductive ZnO: (Al, Mn) thin films

Raman spectroscopy results obtained for undoped and Al- and/or Mn-doped ZnO thin films produced by RF-sputtering are reported. The effect of the doping method (either co-sputtering or ion implantation), the dopant type and its concentration on the Raman-active vibrational modes in these films were studied in detail. The results are discussed with focus on the peak shifts and broadening, and on the doping-induced relaxation of the symmetry selection rules. A particular attention is paid to the 520-530 cm-1 Raman band observed in all Mn containing samples and a simple theoretical model and arguments are presented in support of its relation to the local (gap) phonon mode produced by Mn atoms substituting Zn in the cationic sublattice of the ZnO crystal.Karlsruhe Nano Micro Facility (KNMF), a Helmholtz Research Infrastructure at KI

Influence of surface morphology on erosion of plasma-facing components in H-mode plasmas of ASDEX Upgrade

Net erosion of plasma-facing materials was investigated at the low-field-side (outer) strike-point area of the ASDEX Upgrade (AUG) divertor during H-mode discharges with small and frequent ELMs. To this end, Au and Mo marker samples with different surface morphologies and geometries were exposed to plasmas using the DIMII divertor manipulator. The results were compared to existing erosion and deposition patterns from various Land H-mode experiments, in the latter case the main difference was the size and frequency of the ELMs. We noticed that increasing surface roughness reduces net erosion but less than what is the case in L-mode. On the other hand, net-erosion rates in H-mode are generally 2–5 times higher than the corresponding L-mode values, in addition to which exposure in H-mode conditions results in strong local variations in the poloidal and toroidal erosion/deposition profiles. The latter observation we associate with the large migration length, on the order of several cm, of the eroded material, resulting in strong competition between erosion and re-deposition processes especially at poloidal distances > 50 mm from the strike point. Considerable net erosion was measured throughout the analysed poloidal region unlike in L-mode where the main erosion peak occurs in the vicinity of the strike point. We attribute this qualitative difference to the slow decay lengths of the plasma flux and electron temperature in the applied H-mode scenario. Both erosion and deposition require detailed analyses at the microscopic scale and the deposition patterns may be drastically different for heavy and light impurities. Generally, the rougher the surface the more material will accumulate on locally shadowed regions behind protruding surface features. However, rough surfaces also exhibit more non-uniformities in the quality or even integrity of marker coatings produced on them, thus complicating the analyses of the experimental data. We conclude that local plasma parameters have a huge impact on the PFC erosion rates and, besides incident plasma flux, surface morphology and its temporal evolution have to be taken into account for quantitative estimates of erosion rates and PFC lifetime under reactor-relevant conditions

Plasma–wall interaction studies within the EUROfusion consortium : progress on plasma-facing components development and qualification

The provision of a particle and power exhaust solution which is compatible with first-wall components and edge-plasma conditions is a key area of present-day fusion research and mandatory for a successful o peration of ITER and DEMO. The work package plasma-facing components (WP PFC) within the European fusion programme complements with laboratory experiments, i.e. in linear plasma devices, electron and ion beam loading f acilities, the studies performed in toroidally confined magnetic devices, such as JET, ASDEX Upgrade, WEST etc. The connection of both groups is done via common physics and engineering studies, including the qualificat ion and specification of plasma-facing components, and by modelling codes that simulate edge-plasma conditions and the plasma–material interaction as well as the study of fundamental processes. WP PFC addresses these c ritical points in order to ensure reliable and efficient use of conventional, solid PFCs in ITER (Be and W) and DEMO (W and steel) with respect to heat-load capabilities (transient and steady-state heat and particle lo ads), lifetime estimates (erosion, material mixing and surface morphology), and safety aspects (fuel retention, fuel removal, material migration and dust formation) particularly for quasi-steady-state conditions. Alter native scenarios and concepts (liquid Sn or Li as PFCs) for DEMO are developed and tested in the event that the conventional solution turns out to not be functional. Here, we present an overview of the activities with an emphasis on a few key results: (i) the observed synergistic effects in particle and heat loading of ITER-grade W with the available set of exposition devices on material properties such as roughness, ductility and m icrostructure; (ii) the progress in understanding of fuel retention, diffusion and outgassing in different W-based materials, including the impact of damage and impurities like N; and (iii), the preferential sputtering of Fe in EUROFER steel providing an in situ W surface and a potential first-wall solution for DEMO.Peer reviewe

Plasma-wall interaction studies within the EUROfusion consortium: Progress on plasma-facing components development and qualification

This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme 2014-2018 under grant agreement No 633053. The views and opinions expressed herein do not necessarily reflect those of the European Commission.The provision of a particle and power exhaust solution which is compatible with first-wall components and edge-plasma conditions is a key area of present-day fusion research and mandatory for a successful operation of ITER and DEMO. The work package plasma-facing components (WP PFC) within the European fusion programme complements with laboratory experiments, i.e. in linear plasma devices, electron and ion beam loading facilities, the studies performed in toroidally confined magnetic devices, such as JET, ASDEX Upgrade, WEST etc. The connection of both groups is done via common physics and engineering studies, including the qualification and specification of plasma-facing components, and by modelling codes that simulate edge-plasma conditions and the plasma-material interaction as well as the study of fundamental processes. WP PFC addresses these critical points in order to ensure reliable and efficient use of conventional, solid PFCs in ITER (Be and W) and DEMO (W and steel) with respect to heat-load capabilities (transient and steady-state heat and particle loads), lifetime estimates (erosion, material mixing and surface morphology), and safety aspects (fuel retention, fuel removal, material migration and dust formation) particularly for quasi-steady-state conditions. Alternative scenarios and concepts (liquid Sn or Li as PFCs) for DEMO are developed and tested in the event that the conventional solution turns out to not be functional. Here, we present an overview of the activities with an emphasis on a few key results: (i) the observed synergistic effects in particle and heat loading of ITER-grade W with the available set of exposition devices on material properties such as roughness, ductility and microstructure; (ii) the progress in understanding of fuel retention, diffusion and outgassing in different W-based materials, including the impact of damage and impurities like N; and (iii), the preferential sputtering of Fe in EUROFER steel providing an in situ W surface and a potential first-wall solution for DEMO.European Commission; Consortium for Ocean Leadership 633053; Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART

Changes in respiratory function impairment following the treatment of severe pulmonary tuberculosis – limitations for the underlying COPD detection

Milan Radovic,1,2 Lidija Ristic,1,2 Zorica Ciric,1,2 Violeta Dinic-Radovic,3 Ivana Stankovic,1,2 Tatjana Pejcic,1,2 Milan Rancic,1,2 Dragan Bogdanovic4 1Department of Internal Medicine, Faculty of Medicine, University of Nis, 2Clinic for Lung Diseases, 3Clinic for Gastroenterology and Hepatology, Clinical Centre of Nis, 4Public Health Institute Nis, Nis, Republic of Serbia Background: During the treatment phase of active pulmonary tuberculosis (PTB), respiratory function impairment is usually restrictive. This may become obstructive, as a PTB-associated airflow obstruction (AFO) or as a later manifestation of underlying COPD.Purpose: The aim of the study was to examine the potential causes and risks for AFO development in PTB by exploring the aspects of spirometry limitations and clinical implications for the underlying COPD detection, taking into account various confounding factors.Patients and methods: Prospective, nest case–control study on 40 new cases of PTB with initial restrictive respiratory function impairment, diagnosed and treated according to the directly observed treatment short course (DOTS) strategy.Results: From all observed patients, 37.5% of them developed AFO upon the completion of PTB treatment, with significantly increased average of forced vital capacity (%) (P<0.01). Their changes in forced expiratory volume in the first second (%) during the PTB treatment were strongly associated with the air pollution exposure in living (0.474%–20.971% for 95% confidence interval [CI]; P=0.041) and working environments (3.928%–20.379% for 95% CI; P=0.005), initial radiological extent of PTB lesions (0.018%–0.700% for 95% CI; P=0.047), leukocyte count (0.020%–1.328% for 95% CI; P=0.043), and C-reactive protein serum level (0.046%–0.205% for 95% CI; P=0.003) compared to the other patients. The multivariate logistic regression analysis model shows initial radiological extent of pulmonary tuberculosis lesions (OR 1.01–1.05 for 95% CI; P=0.02) and sputum conversion rate on culture (OR 1.02–1.68 for 95% CI; P=0.04) as the most significant predictors for the risk of AFO development.Conclusion: AFO upon PTB treatment is a common manifestation of underlying COPD, which mostly occurs later, during the reparative processes in active PTB, even in the absence of major risk factors, such as cigarette smoking and biomass fuel dust exposure. Initial spirometry testing in patients with active PTB is not a sufficient and accurate approach in the detection of underlying COPD, which may lead to their further potential health deterioration. Keywords: tuberculosis, pulmonary, respiratory function tests, lung diseases, obstructiv

Ion beam synthesis and characterization of Ge nanoparticles in SiO2

Ge quantum dots embedded in SiO2 have been obtained by implantation of Ge ions in the 10(16)-10(17) cm(-2) dose range, followed by post-implantation annealing in the temperature range T-a = 300-1000 degrees C. Using Rutherford back-scattering, grazing incidence X-ray diffraction and grazing incidence small angle X-ray scattering it was found that Ge-QDs are synthesized as discrete, spherical QDs, with radius ranging from 1.7 to 10 nm, depending on dose and T-a. For T-a above 800 degrees C the Ge atom diffusion becomes considerable, leading to a strong increase of both size and size distribution of Ge QDs, but still without sizeable loss of Ge atoms from the implanted layer

Femtosecond laser-induced periodic surface structure on the Ti-based nanolayered thin films

Laser-induced periodic surface structures (LIPSSs) and chemical composition changes of Ti-based nanolayered thin films (Al/Ti, Ni/Ti) after femtosecond (fs) laser pulses action were studied. Irradiation is performed using linearly polarized Ti:Sapphire fs laser pulses of 40 fs pulse duration and 800 nm wavelength. The low spatial frequency LIPSS (LSFL), oriented perpendicular to the laser polarization with periods slightly lower than the irradiation wavelength, was typically formed at elevated laser fluences. On the contrary, high spatial frequency LIPSS (HSFL) with uniform period of 155 nm, parallel to the laser light polarization, appeared at low laser fluences, as well as in the wings of the Gaussian laser beam distribution for higher used fluence. LSFL formation was associated with the material ablation process and accompanied by the intense formation of nanoparticles, especially in the Ni/Ti system. The composition changes at the surface of both multilayer systems in the LSFL area indicated the intermixing between layers and the substrate. Concentration and distribution of all constitutive elements in the irradiated area with formed HSFLs were almost unchanged. (C) 2013 AIP Publishing LLC