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681.
The bioluminescence emitted by micro-planktonic organisms has been adopted to detect shear stresses within oscillating flows
over small scale bedforms. To this aim, an experimental campaign has been planned in order to optimize optical detectors and
to address peculiar needs of biological organisms. 相似文献
682.
A sapphire micro-lens system in combination with a zirconium-fluoride (ZrF4) fibre has been designed and constructed as a surgical tool for focusing Er:YAG-laser radiation. It both refocuses the laser radiation transmitted through a 350 µm core fibre to a spot diameter of 570 µm at a working distance of 7.6 mm, and protects the distal fibre end from damage. An accurate and uncomplicated visualization of the focus position of the erbium-laser beam is realized by coupling a HeNe aiming laser into the cladding of the fibre. In vitro cutting experiments reveal the high cutting precision with minimal thermal damage of the surrounding tissue and the high damage resistance of the system. It may render the use of the erbium laser possible in a wide range of endoscopic applications. 相似文献
683.
L. Campajola L. Gialanella K. Brand A. D’Onofrio U. Greife E. Huttel R. Kubat G. Oliviero H. Rebel V. Roca C. Rolfs M. Romano M. Romoli S. Schmidt W. H. Schulte F. Strieder F. Terrasi H. -P. Trautvetter D. Zahnow 《Zeitschrift für Physik A Hadrons and Nuclei》1986,356(2):107-109
For an improved determination of the 7Be(p, γ)8B absolute cross section, the reaction is studied in inverse kinematics. The study involves a 7Be radioactive ion beam of 8.0 MeV, a windowless H2 gas target, and an efficient recoil separator for the detection of the 8B residual nuclides. The techniques used to produce such a beam as well as the first direct observation of 8B are reported. 相似文献
684.
Summary It is well-known that periodic solutions of semilinear wave equations can be obtained as critical points of related functionals. In the situation that we studied, there is usually an obvious solution obtained as a solution of linear problem. We formulate a dual variational problem in such a way that the obvious solution is a local minimum. We then find additional non-obvious solutions via a numerical mountain pass algorithm, based on the theorems of Ambrosetti, Rabinowitz and Ekeland. Numerical results are presented.Research supported in part by grant DMS-9208636 from the National Science FoundationResearch supported in part by grant DMS-9102632 from the National Science Foundation 相似文献
685.
J.M. Yáñez-Limón J.F. Pérez-Robles J. González-Hernández Yuri V. Vorobiev J.A. Romano F.C.G. Gandra E.C. Da Silva 《Journal of Sol-Gel Science and Technology》2000,18(3):207-217
SiO2 Glasses with incorporation of either Cu or Fe were prepared by the sol-gel process and annealed in air at temperatures within the range of 100 to 500°C. The samples were characterized using Visible Photoacoustic Absorption Spectroscopy (PAS), X-ray powder diffraction and Electron Paramagnetic Resonance (EPR). Under the annealing both systems show significant changes in composition, producing an evolution in the optical absorption spectra. In both systems, the formation of the metal oxide particles is observed after annealing at or above 300°C. The optical and EPR spectra are interpreted in terms of the coordination of the metal ions using the ligand field theory. It is observed that the color of the samples has strong change with both the type of metal incorporated and with the annealing temperature. 相似文献
686.
R. P. Paiva C. S. Munita I. I. L. Cunha C. D. Alonso J. Romano M. H. R. Martins 《Journal of Radioanalytical and Nuclear Chemistry》1993,167(2):295-307
Fine and coarse particles in suspension in the atmosphere were collected on two Teflon filters with a dichotomous sampler. The concentration of Al, Br, Ca, Ce, Cl, Co, Cr, Fe, K, La, Mn, Na, P, Pb,, S, Sb, Sc, Se, Si, Sm, Th, V and Zn was determined by ED-XRF and INAA. The elemental concentration was analyzed by means of linear correlation coefficients, enrichment factors and principal factors analysis in order to identify the aerosol sources. The main sources of the aerosol particles were the marine ones, resuspended soil, fuel-oil combustion, phosphatic rocks, refuse incineration and residual high-temperature processes. 相似文献
687.
Summary Because methylmalonic acid (MMA) accumulates in the body fluids of patients suffering from inherited metabolic disorders involving its pathway, the quantitation of this metabolite is not only fundamental to diagnosis but is also important in the follow-up of affected patients under treatment.We describe the method set up and used in our laboratory for the measurement of MMA in body fluids and propose its application to plasma as the reference method for the biochemical diagnosis and follow-up of methylmalonic acidaemias. 相似文献
688.
A. D. Zweig M. Frenz V. Romano H. P. Weber 《Applied physics. B, Lasers and optics》1988,47(3):259-265
Laser cutting of gelatin and tissue with Er and CO2 lasers is explained by combined action of evaporation, ejection of liquid and elastic deformation of the region of radiation impact. It is shown that the ejection mechanism is more pronounced at 2.94 m than at 10.6 m. The use of high speed photography has revealed the influence of the temporal pulse shape. The experimental results are explained by a thermo-mechanical model. 相似文献
689.
Joseph J. Romano 《Tetrahedron letters》2005,46(13):2323-2326
Advanced C-prenylated intermediates for three aromatase inhibitors, including morachalcone A, can be synthesized through a Claisen-Schmidt condensation followed by Florisil®-catalyzed [1,3]-sigmatropic rearrangement of a prenyl phenyl ether. 相似文献
690.
Monte Carlo calculations for clusters consisting of 200 water molecules surrounding glycine in the neutral and zwitterionic forms were carried out at 300 K; all the relevant interaction potentials have been obtained by means of quantum–mechanical calculations. Water–water and amino acid–water energies were calculated, and the zwitterion was found to be strongly favored with respect to the neutral molecule, as expected. A detailed analysis of the energetic results yielded some information on the special extension of the solute-induced perturbation. The structural results were found to be in reasonable agreement with predictions that can be obtained by analyzing isoenergy contour maps, calculated for the two-body amino acid–water potential. 相似文献