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51.
M. L. De Giorgi G. Leggieri A. Luches M. Martino A. Perrone G. Majni P. Mengucci J. Zemek I. N. Mihailescu 《Applied Physics A: Materials Science & Processing》1995,60(3):275-283
Silicon-nitride films were deposited on silicon waters by XeCl (308 nm) excimer-laser ablation of silicon in low-pressure (0.05–5 mbar) ammonia atmospheres. Series of 10 000 pulses at the repetition rate of 8 Hz were directed to the target surface. The fluence was set at about 5 J/cm2. Pulse duration was about 30 ns. The deposited films were characterized by different techniques (X-ray diffraction, X-ray photoelectron spectroscopy, Auger electron spectroscopy, Rutherford backscattering spectrometry, scanning electron microscopy, profilometry). Silicon-nitride films with thickness close to 1 m were obtained under specific experimental conditions. 相似文献
52.
Tamoxifen is an antiestrogenic drug which is used in the treatment of breast cancer and nonmalignant breast disorders. It also has a stimulating effect on the secretion of hypofisar gonadotropic hormones and is generally used in the treatment of infertility. In males, tamoxifen causes an increase of endogenous production of androgenic steroids, and therefore is used by athletes. A method for identification of tamoxifen and metabolites in urine, using the gas chromatography and mass spectrometry system (GC/MS) is described. This study also reports the extraction methodology of tamoxifen and metabolites in urine samples of healthy male volunteers and the GC/MS conditions used to identify tamoxifen and its metabolites. 相似文献
53.
54.
A. A. Pasternak E. O. Podsvirova R. M. Lieder S. Chmel W. Gast Ts. Venkova H. M. Jäger L. Mihailescu G. de Angelis D. R. Napoli A. Gadea D. Bazzacco R. Menegazzo S. Lunardi W. Urban Ch. Droste T. Morek T. Rzaca-Urban G. Duchêne A. Dewald 《The European Physical Journal A - Hadrons and Nuclei》2005,23(2):191-196
Lifetimes have been measured for dipole bands in 142Gd using DSAM. The deduced B(M1) and B(E2) values as well as B(M1)/B(E2) ratios are compared with calculations in the framework of the TAC (Tilted Axis Cranking) and SPAC (Shears mechanism with Principal Axis Cranking) models. The dipole bands DB1 to DB4 can be interpreted as magnetic rotational bands. 相似文献
55.
Three-dimensional memory effect in fluorescent photosensitive glass activated by europium and cerium
Pavel E Mihailescu IN Hening A Vlad VI Tugulea L Diamandescu L Bibicu I Chipara M 《Optics letters》1998,23(16):1304-1306
The persistent extinction of fluorescence emission of Eu(3+) in glasses activated with europium and cerium is reported for the first time to the authors' knowledge. The glass samples containing Eu(3+) and Ce(3+) were initially colorless and transparent and exhibited intense emission peaks at 592 and 612 nm assigned to the (5)D(0)-(7)F(1, 2) transitions of Eu(3+). The complete extinction of the Eu(3+)-ion emission was obtained as an effect of multipulse excimer-UV-laser (lambda = 248 nm, tau(FWHM) >/= 20 ns) irradiation of the glass samples. Fluorescence microscopy, M?ssbauer spectrometry, and electron spin resonance were applied for investigation of the modifications induced by the laser treatment. As a decisive proof of the extinction of fluorescence we succeeded in recording three-dimensional fluorescent photographic patterns within the activated samples. 相似文献
56.
I. Ursu L. C. Nistor V. S. Teodorescu S. V. Nistor I. N. Mihailescu N. N. Kolesnikov V. I. Konov M. P. Kulakov Yu. M. Starodumov N. I. Chapliev V. E. Shub 《Applied Physics A: Materials Science & Processing》1989,48(5):451-456
A microscopy study of the morphology of the damage produced by TEA-CO2 laser pulses in cubic ZnSe single crystals grown from melt is presented. The observed bulk filamentary damage consists of relatively uniformly distributed elementary damaged zones, located at specific sites where absorbing inclusions could exist. Transmission electron microscopy and laser ion mass spectroscopy investigations revealed the absorbing inclusions to be thin graphite foils, originating from the crucible used for crystal growth. 相似文献
57.
I. Fasaki A. Giannoudakos M. Stamataki M. Kompitsas E. György I.N. Mihailescu F. Roubani-Kalantzopoulou A. Lagoyannis S. Harissopulos 《Applied Physics A: Materials Science & Processing》2008,91(3):487-492
Transparent nickel oxide thin films were grown by reactive pulsed laser deposition. An ArF* (λ=193 nm, τ=12 ns) excimer laser
source was used to ablate the Ni targets in a controlled pressure of ambient oxygen. The substrates were either kept at room
temperature or heated to a selected temperature within the 200–400 °C range. Post-deposition heat treatment, which was applied
to further promote crystallization and overcome any oxygen deficiency, yielded transparent thin films. The surface morphology
and crystalline status of the synthesized thin structures were analyzed in correlation with their optical properties. A significant
response to several concentrations of hydrogen was demonstrated when heating the nickel oxide films at 185 °C.
PACS 78.66.Hf; 81.15.Fg; 82.47.Rs 相似文献
58.
Eugen Mihailescu 《Monatshefte für Mathematik》2012,139(5):241-255
We study certain ergodic properties of equilibrium measures of hyperbolic non-invertible maps f on basic sets with overlaps Λ. We prove that if the equilibrium measure of a Holder potential , is 1-sided Bernoulli, then f is expanding from the point of view of a pointwise section dimension of . If the measure of maximal entropy μ 0 is 1-sided Bernoulli, then f is shown to be distance expanding on Λ; and if is 1-sided Bernoulli for f expanding, then must be the measure of maximal entropy. These properties are very different from the case of hyperbolic diffeomorphisms. Another result is about the non 1-sided Bernoullicity for certain equilibrium measures for hyperbolic toral endomorphisms. We also prove the non-existence of generating Rokhlin partitions for measure-preserving endomorphisms in several cases, among which the case of hyperbolic non-expanding toral endomorphisms with Haar measure. Nevertheless the system is shown to have always exponential decay of correlations on Holder observables and to be mixing of any order. 相似文献
59.
Eugen Mihailescu 《Monatshefte für Mathematik》2012,167(2):241-255
We study certain ergodic properties of equilibrium measures of hyperbolic non-invertible maps f on basic sets with overlaps Λ. We prove that if the equilibrium measure \({\mu_\phi}\) of a Holder potential \({\phi}\) , is 1-sided Bernoulli, then f is expanding from the point of view of a pointwise section dimension of \({\mu_\phi}\) . If the measure of maximal entropy μ 0 is 1-sided Bernoulli, then f is shown to be distance expanding on Λ; and if \({\mu_\phi}\) is 1-sided Bernoulli for f expanding, then \({\mu_\phi}\) must be the measure of maximal entropy. These properties are very different from the case of hyperbolic diffeomorphisms. Another result is about the non 1-sided Bernoullicity for certain equilibrium measures for hyperbolic toral endomorphisms. We also prove the non-existence of generating Rokhlin partitions for measure-preserving endomorphisms in several cases, among which the case of hyperbolic non-expanding toral endomorphisms with Haar measure. Nevertheless the system \({(\Lambda, f, \mu_\phi)}\) is shown to have always exponential decay of correlations on Holder observables and to be mixing of any order. 相似文献
60.
E. György J. Santiso A. Giannoudakos I.N. Mihailescu 《Applied Surface Science》2006,252(13):4429-4432
Nanostructures formed by Au nanoparticles on ZnO thin film surface are of interest for applications which include medical implants, gas-sensors, and catalytic systems. A frequency tripled Nd:YAG laser (λ = 355 nm, τFWHM ∼ 10 ns) was used for the successive irradiation of the Zn and Au targets. The ZnO films were synthesized in 20 Pa oxygen pressure while the subsequent Au coverage was grown in vacuum. The obtained structures surface morphology, crystalline quality, and chemical composition depth profile were investigated by acoustic (dynamic) mode atomic force microscopy, X-ray diffraction, and wavelength dispersive X-ray spectroscopy. The surface is characterized by a granular morphology, with average grain diameters of a few tens of nanometers. The surface roughness decreases with the increase of the number of laser pulses applied for the irradiation of the Au target. The Au coverage reveals a predominant (1 1 1) texture, whereas the underlying ZnO films are c-axis oriented. A linear dependence was established between the thickness of the Au coverage and the number of laser pulses applied for the irradiation of the Au target. 相似文献