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Proton Irradiation (proton + irradiation)
Selected AbstractsFerromagnetic Spots in Graphite Produced by Proton Irradiation,ADVANCED MATERIALS, Issue 20 2003K.-h. Han A proton microbeam produces ferromagnetic spots on a highly oriented graphite surface. The Figure shows the topography and the magnetic force microscopy (MFM) images obtained after irradiating the surface with a beam size of 1,,m,×,1 ,m and a dose of 0.098 nC,,m,2. The strength of the magnetic signal is only a factor of ,,10 smaller than that obtained on Fe particles. [source] The effect of surface treatments on the fretting behavior of Ti-6Al-4V alloyJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 2 2008Matteo Dalmiglio Abstract Stem modularity in total hip replacement introduces an additional taper joint between Ti-6Al-4V stem components with the potential for fretting corrosion processes. One possible way to reduce the susceptibility of the Ti-6Al-4V/Ti-6Al-4V interface to fretting is the surface modification of the Ti-6Al-4V alloy. Among the tested, industrially available surface treatments, a combination of two deep anodic spark deposition treatments followed by barrel polishing resulted in a four times lower material release with respect to untreated, machined fretting pad surfaces. The fretting release has been quantified by means of radiotracers introduced in the alloy surface by proton irradiation. In a simple sphere on flat geometry, the semispherical fretting pads were pressed against flat, dog-bone shaped Ti-6Al-4V fatigue samples cyclically loaded at 4 Hz. In this way a cyclic displacement amplitude along the surfaces of 20 ,m has been achieved. A further simplification consisted in the use of deionized water as lubricant. A comparison of the radiotracer results with an electrochemical material characterization after selected treatments by potentiostatic tests of modular stems in 0.9% NaCl at 40°C for 10 days confirmed the benefit of deep anodic spark deposition and subsequent barrel polishing for improving the fretting behavior of Ti-6Al-4V. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008 [source] Synthesis of 13C-labelled cinnamonitrileJOURNAL OF LABELLED COMPOUNDS AND RADIOPHARMACEUTICALS, Issue 2 2002Elizabeth M. Zippi Abstract 13C-labelled cinnamonitrile, a compound that possesses both the aromatic functionality of styrene and the nitrile functionality of acrylonitrile has been synthesized in one step using , -bromostyrene and potassium [13C]cyanide. The preparation of a target material using 13C -labelled cinnamonitrile may provide a cost-effective method for producing nitrogen-13 via proton irradiation for Positron Emission Tomography. Copyright © 2002 John Wiley & Sons, Ltd. [source] Synthesis of Phenyl-13C6-etheneJOURNAL OF LABELLED COMPOUNDS AND RADIOPHARMACEUTICALS, Issue 11 2001Elizabeth M. Zippi Abstract In an effort to prepare an improved carbon-rich target material for the accelerator production of 13N labelled ammonia for use in positron emission tomography (PET), sulfonated poly(styrene/divinylbenzene) has been evaluated. The preparation of this target material using naturally abundant carbon-12 compounds was investigated in an effort to optimize conditions for the preparation of the analogous carbon-13 target material which may provide a cost-effective method for producing nitrogen-13 labelled ammonia via proton irradiation. As part of this study, phenyl-13C6-ethene was synthesized in three steps starting from benzene-13C6. Copyright © 2001 John Wiley & Sons, Ltd. [source] An additional phase in PCr use during sustained isometric exercise at 30% MVC in the tibialis anterior muscleNMR IN BIOMEDICINE, Issue 4 2002C. J. Houtman Abstract The occurrence of an abrupt acceleration in phosphocreatine hydrolysis in the tibial anterior muscle during the last part of a sustained isometric exercise at 30% maximal voluntary contraction until fatigue is demonstrated in seven out of eight healthy subjects by applying in vivo31P NMR spectroscopy at 1.5,T field strength. This additional third phase in PCr hydrolysis, is preceded by a common biphasic pattern (first fast then slow) in PCr use. The NMR spectra, as localized by a surface coil and improved by proton irradiation, were collected at a time resolution of 16 s. Mean rates of PCr hydrolysis during exercise were ,0.44,±,0.19% s,1, ,0.07,±,0.04% s,1, and ,0.29,±,0.10% s,1 for the three successive phases. The increased rate of PCr hydrolysis, and also the loss of fine force control evident in the force records are consistent with increased involvement of large, fast-fatiguable units later in the contraction. Copyright © 2002 John Wiley & Sons, Ltd. [source] Radiation effects in sapphire optical fibersPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 3 2007Dan Sporea Abstract Radiation effects on sapphire optical fibers were investigated using off-line gamma-ray, neutron and electron beam irradiation and on-line proton irradiation. The optical attenuation of these optical fibers was studied from UV to IR (200 nm , 1700 nm). For the in-situ measurements radioluminescence was also investigated as function of the total irradiation dose. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] | ||||||||||