Search results for "RADIATION"

Structure and Physical Properties of Na1/2Bi1/2TiO3-CdTiO3Solid Solutions

2011

Behaviour of ferroelectric properties in Na1/2Bi1/2TiO3-CdTiO3 solid solutions correlates with dependence of lattice symmetry versus concentration of constituents. However, some overlapping is observed in concentration range close to the morphotropic phase boundary. The properties of dielectric permittivity, characteristic for relaxor ferroelectrics, diminish, if concentration of CdTiO3 increases, but it is not influenced by the change of crystallographic symmetry. The electromechanical properties are mostly pronounced in the range of cubic-tetragonal morphotropic phase boundary.

Carbonyl metallo immuno assay: a new application for Fourier transform infrared spectroscopy

2000

Abstract We describe here the development of a new, non-isotopic immunological assay termed CMIA (carbonyl metallo immunoassay) that uses metal carbonyl complexes as tracers and Fourier transform infrared spectroscopy (FT-IR) as the detection method. This assay is based on the particular spectral features of these complexes, which show very strong absorption bands in the 1800–2200 cm −1 spectral range where proteins and organic molecules do not absorb. In Section 1 , the optimisation of the quantitative detection of these tracers is detailed. In Section 2 , the implementation of mono-CMIA is described, including the CMIA assays of three antiepileptic drugs (carbamazepine, phenobarbital, phe…

Immunosuppressant therapy of thyroid eye disease.

1988

Thyroid eye disease is attributed to an autoimmune process where both cellular and humoral immunity play a role. In this report, after a short introduction dealing with immunopathogenesis of the disease, immunosuppressant therapy is discussed. Treatment with glucocorticoids (as the standard substance), nonsteroid immunosuppressants (azathioprine, cyclophosphamide, lately cyclosporin) and with the immunomodulatory substance ciamexone is reviewed. Retroorbital irradiation as a "local" immunosuppressive method and plasmapheresis are also discussed. While systemic glucocorticoids and to a lesser extent orbital radiotherapy are routinely administered for severe Graves' ophthalmopathy, nonsteroid…

Guided Surgery and Immediate Loading

2019

Computer-assisted implant dentistry can contribute for a better treatment planning, for the implementation of the implant placement, for capturing the intraoral situation, for processing data to design temporary and final prostheses, and for the manufacturing of prosthetic components.

<title>Annealing of radiation defects in x-irradiated LiBaF<formula><inf><roman>3</roman></inf></formula>&l…

2003

Results of the glow rate technique application for analysis of the activation energy of thermostimulated annealing of X-ray created F-type color centers in pure and containing oxygen centers LiBaF3 crystals are presented. It is shown that depending on the impurity composition two alternative mechanisms could be involved in the annealing of color centers. It is proposed that either the anion vacancy governed migration of F-centers resulting in recombination with complementary defects, or the thermal delocalization of radiation created fluorine (Fi) interstitials captured by anti-structure defects followed by recombination with all kinds of complementary F-type centers are responsible for the…

2016

Abstract. To date, very little is known about the distribution of natural gas hydrates in sedimentary matrices and its influence on the seismic properties of the host rock, in particular at low hydrate concentration. Digital rock physics offers a unique approach to this issue yet requires good quality, high-resolution 3-D representations for the accurate modeling of petrophysical and transport properties. Although such models are readily available via in situ synchrotron radiation X-ray tomography, the analysis of such data asks for complex workflows and high computational power to maintain valuable results. Here, we present a best-practice procedure complementing data from Chaouachi et al.…

Generation of defects in amorphous SiO(2) assisted by two-step absorption on impurity sites.

2011

Generation of the Si dangling bond defect in amorphous SiO(2) (E' centre) induced by tunable pulsed UV laser radiation was investigated by in situ optical absorption measurements. The defect generation efficiency peaks when the photon energy equals ∼5.1 eV, it depends quadratically on laser intensity and is correlated with the native linear absorption due to Ge impurities. We propose a model in which the generation of E' is assisted by a two-step absorption process occurring on Ge impurity sites.

Influence of irradiation on the switching behavior in PZT thin films

2005

Spatially nonuniform imprint behavior induced by X-ray synchrotron, electron and neutron irradiation has been investigated in sol–gel Pb(Zr,Ti)O3 thin films. The analysis of the switching current data reveals the strong influence of irradiation on the switching current shape. The obtained effects have been explained as a result of acceleration of the bulk screening process induced by irradiation. It was shown that the spatial distribution of the internal bias field is determined by the domain structure existing during irradiation. The changes in the structural characteristics during fatigue cycling have been reveled by high resolution synchrotron X-ray diffraction experiments on (1 1 1)-ori…

In situ synchrotron radiation monitoring of phase transitions during microwave heating of Al–Cu–Fe alloys

2008

The effect of rapid microwave heating has so far been evaluated mainly by comparing the state of materials before and after microwave exposure. Yet, further progress critically depends on the ability to follow the evolution of materials during ultrafast heating in real time. We describe the first in situ time-resolved monitoring of solid-state phase transitions during microwave heating of metallic powders using wide-angle synchrotron radiation diffraction. Single-phase Al–Cu–Fe quasicrystal powders were obtained by microwave heating of nanocrystalline alloy precursors at 650 °C in <20 s.

Using ultrasound transmission velocity to analyse the mechanical properties of teeth after in vitro, in situ, and in vivo irradiation.

2000

Ultrasound transmission velocity (UTV) in isotropic material as a measure for the modulus of elasticity was correlated to mechanical properties. Changes in micromechanical properties of radiated teeth and influence of the oral cavity were to be evaluated nondestructively. UTV was measured in extracted teeth after 36 Gy and 62 Gy of in situ (enorally, with no contact to the oral cavity) and in vitro irradiation. Relative to controls, teeth subjected to 62 Gy in vivo showed higher UTV values for dentine and enamel. Sound teeth irradiated with 60 Gy in situ also showed higher UTV values for enamel, whereas dentine values were not significantly different from those of control. The mechanical pr…