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901.
902.
P. Gorria D. Martínez-Blanco R. Iglesias S.L. Palacios M.J. Pérez J.A. Blanco L. Fernández Barquín A. Hernando M.A. González 《Journal of magnetism and magnetic materials》2006
The magnetic properties of Fe–Cu metastable solid solutions have been investigated by means of neutron diffraction and magnetisation measurements. These compounds exhibit ferromagnetic order with Curie temperatures above room temperature for concentrations beyond 40 at% in Fe. The magnetic moment at 5 K can reach values over 2 μB, while the high field susceptibility is similar to that found in FCC–FeNi Invar alloys. These features together with the low values for the linear coefficient for thermal expansion in the ferromagnetic region suggest that magneto-volume anomalies, including Invar behaviour, play a major role in the magnetic properties of this system when the crystal structure is face centred cubic. Such behaviour could be explained using theoretical total-band energy calculations. 相似文献
903.
Seventeen triorganotin(IV) compounds, with the general formula R3SnX, containing symmetrical and unsymmetrical combinations of alkyl and aryl groups on tin and with a wide variation in the non-carbon-bonded anionic (X) residues, were examined along with three formally pentacoordinated adducts of triaryltin chlorides with triphenylphosphine oxide for their antifungal activity against nine plant pathogenic and saprophytic fungi. The in vitro tests included inhibitory studies on radial growth, mycelial growth, spore germination, and germ tube elongation. A significant finding was the dependence of fungitoxicity on the nature of the X group in both the tributyltin and triaryltin series, in contrast to earlier published reports on the negligible influence of the X groups on overall toxicity relative to the R group. This suggests that the X group is significantly involved in transporting the biocide to the reactive sites, and that the X group which tends to confer increased solubility to the triorganotin compound gives rise to increased activity. In studies of R group variations, tri-iso-butyltin bromide was found to be much less fungitoxic than tri-n-butyltin compounds, a result which is reconcilable in terms of increased steric encumbrance at the tin site in the former case. The steric factor is also implicated in the reduced activities observed for tris(p-tolyl)tin and tris(p-chlorophenyl)tin compounds relative to (Ph3SnX) towards most of the fungi screened in this study. In general, it was also noted that the triaryltins were more selective in their antifungal action than the trialkyltins, which exhibited broad spectral activity when applied at the concentration level of 10 μg cm?3. 相似文献
904.
905.
In this paper, we present experimental data for SIMS analysis of residual gas elements (RGEs) with a Cameca IMS-6f ion microprobe. We considered a simple experimental technique, which provides an effective separation of the secondary ions, sputtered from the bulk of a target, and from the molecules, adsorbed on the analyzed surface from the residual atmosphere. The technique needs the sputtering yield of one monolayer (ML) per second to be applied. The method improves (in more than one order of magnitude) the detection limit for RGEs in SIMS analysis, and simultaneously, provides information about the residual atmosphere at the sample surface and in the main chamber of the experimental instrument. The method provides a calibration method for an ion gauge, and can be used for SIMS analysis with a gas (O2) flooding. 相似文献
906.
M. Mahjour-Shafiei H.R. Amir-Ahmadi J.C.S. Bacelar R. Castelijns K. Ermisch E.D. van Garderen I. Gašparić M.N. Harakeh N. Kalantar-Nayestanaki M. Kiš H. Löhner O. Scholten 《Physics letters. [Part B]》2006
A series of nucleon–nucleon bremsstrahlung (NNγ) experiments at 190 MeV incident beam energy have been performed at KVI in order to gain more insight into the dynamics governing the bremsstrahlung reaction. After initial measurements wherein the bremsstrahlung process was studied far away from the elastic limit, a new study was used to probe the process nearer to the elastic limit by measuring at lower photon energies. Measured cross sections and analyzing powers are compared with the predictions of a microscopic model and those of two soft-photon models. The theoretical calculations overestimate the data by up to ≈30%, for some kinematics. 相似文献
907.
J.D. Dutson D. Litvinov M.R.J. Gibbs Y. Inaba H. Muraoka K. O’Grady 《Journal of magnetism and magnetic materials》2006
In this paper, we discuss two key aspects of magnetisation reversal in magnetic thin films with perpendicular anisotropy. Firstly, a study has been made of the additional field required to erase data written perpendicular to a thin film recording disk as the linear data density is increased. It has been found that an increase in data density from 40 to 360 kfci results in an increase of 1.25 kOe in the field required to erase the data. Secondly, the effect of varying the level of exchange coupling by co-sputtering CoCrPt samples with SiO2 has been studied using a characterisation technique that is independent of the self-demagnetising field. It has been found that the samples are fully exchange de-coupled when the film contains >9.8% SiO2 and the activation volume of reversal remains constant for higher levels of SiO2. 相似文献
908.
We are interested in critical fields for ferromagnetic elements: At which strength of the external field does a branch of stationary magnetizations become unstable, and what is the unstable mode? We consider samples which are infinite in the direction of the external field and have a rectangular cross-section, of much smaller thickness than width, as an idealization of a thin film element. For this geometry Aharoni [Phys. Stat. Sol. 16, 3-42 (1966)] claims that there are only three different regimes: The unstable mode is either of coherent rotation type, of buckling type, or of curling type. We discover a large fourth parameter regime with an unstable mode displaying an oscillation in the infinite direction. We prove the existence of exactly four regimes by rigorously analyzing the scaling of the Rayleigh quotient of the Hessian of the energy functional. The parameters are the film width, the film thickness, and the exchange length. 相似文献
909.
T. Geppert S.L. Schweizer U. Gösele R.B. Wehrspohn 《Applied Physics A: Materials Science & Processing》2006,84(3):237-242
We present a method to create at the same time trenches and ordered macropore arrays during photo-electrochemical etching of n-type silicon. This novel method allows in situ separation of single devices with a submicrometer precision. It also enables new device structures in macroporous silicon in the areas of photonics, sensing and electronics. The limits of this new process are simulated using electrostatic models and are verified experimentally. PACS 82.45.Yz; 81.16.-c 相似文献
910.
A. Badalà R. Barbera G. Lo Re A. Palmeri G. S. Pappalardo A. Pulvirenti F. Riggi 《Acta Physica Hungarica A》2006,25(2-4):337-346
Results are shown from a Monte Carlo simulation study of the capabilities of the Inner Tracking System of the ALICE experiment, used in standalone mode, for HBT analysis of Pb?Pb collisions at LHC energies (5.5 ATeV). Different values of the coherence factor and the Gaussian source radius have been studied. For this purpose, a specific ITS stand-alone tracking algorithm, based on the Denby-Peterson neural algorithm, has been developed. 相似文献