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101.
The manganite La0.67Sr0.33MnO3 (LSMO) layers are deposited on single crystal MgO(0 0 1) substrates using a magnetron dc sputtering. The crystalline perfection of the layers, both the as-prepared and the annealed, are characterized by X-ray diffraction technique, rocking curve measurements, Rutherford backscattering spectroscopy (RBS) and transmission electron microscopy (TEM). TEM analyses give evidence of the epitaxial growth of the annealed LSMO with a nanocrystalline surface layer. The temperature dependence of resistance in the 77-340 K range is measured by a standard four-probe technique. While the as-prepared film does not show any transition from paramagnetic to ferromagnetic state, the film annealed in oxygen shows steep R(T) dependence with a peak at 330 K and maximal slope (dR/dT) at 290 K where the maximal sensitivity is 3% K−1. 相似文献
102.
103.
J.E. Bailey G.A. Chandler G.A. Rochau Y. Maron S.A. Slutz G.S. Dunham I. Golovkin P.W. Lake R.W. Lemke J.M. Lucas J.J. MacFarlane T.A. Mehlhorn T.C. Moore D.G. Schroen E. Stambulchik K. Youngblood 《High Energy Density Physics》2005,1(1):21-30
A dynamic hohlraum is created when an annular z-pinch plasma implodes onto a cylindrical 0.014 g/cc 6-mm-diameter CH2 foam. The impact launches a radiating shock that propagates toward the axis at 350 μm/ns. The radiation trapped by the tungsten z-pinch plasma forms a 200 eV hohlraum that provides X-rays for indirect drive inertial confinement fusion capsule implosion experiments. We are developing the ability to diagnose the hohlraum interior using emission and absorption spectroscopy of Si atoms added as a tracer to the central portion of the foam. Time- and space-resolved Si spectra are recorded with an elliptical crystal spectrometer viewing the cylindrical hohlraum end-on. A rectangular aperture at the end of the hohlraum restricts the field of view so that the 1D spectrometer resolution corresponds approximately to the hohlraum radial direction. This enables distinguishing between spectra from the unshocked radiation-heated foam and from the shocked foam. Typical spectral lines observed include the Si Lyα with its He-like satellites and the He-like resonance sequence including Heα, Heβ, and Heγ, along with some of their associated Li-like satellites. Work is in progress to infer the hohlraum conditions using collisional–radiative modeling that accounts for the radiation environment and includes both opacity effects and detailed Stark broadening calculations. These 6-mm-scale radiation-heated plasmas might eventually also prove suitable for testing Stark broadening line profile calculations or for opacity measurements. 相似文献
104.
The goal of this paper is to prove some general vector-valued perturbed equilibrium principles and some existence results of vector equilibrium points for bifunctions satisfying a new natural notion of lower semi-continuity. We obtain these results by going through a new concept of approximative equilibrium point. 相似文献
105.
M. Dolores Petit Dominguez M. Teresa Sevilla Escribano Jose M. Pinilla Macias Lucas Hernandez Hernandez 《Microchemical Journal》1990,42(3)
A sensitive method for the determination of microamounts of cobalt by ion-exchanger spectrophotometry has been developed. The chromogenic agent, Nitroso-R-Salt (NRS), was loaded on an anionic-exchange resin (Amberlite CG-400). The absorbance of the NRS-cobalt complex on the chelating resin was measured at 508 nm. The best conditions for the preconcentration of cobalt on the resin before the spectrophotometric determination were a pH value of 6, temperature of 80 °C, and heating times of 45 or 90 min for 50 and 400 ml of sample, respectively. The detection limits were 27 ng/ml (50-ml samples) and 1.8 ng/ml (400-ml samples). Interference by other metals was investigated. The method is useful for determination of cobalt in natural waters. 相似文献
106.
107.
Lucas Montero De Espinosa Juan C. Ronda Marina Galià Virginia Cádiz Michael A.R. Meier 《Journal of polymer science. Part A, Polymer chemistry》2009,47(21):5760-5771
The acyclic diene metathesis (ADMET) polymerization of a phosphorus‐containing α,ω‐diene prepared from a plant oil derived building block is reported. Different ruthenium based metathesis catalysts and conditions were tested to optimize the ADMET polymerization of this monomer. Undecylenyl undecenoate was used as fully renewable comonomer to obtain polyesters with different phosphorus contents and to increase the renewable content of the final polymers. Copolymerization caused marked variations in the molecular weights leading to polyesters from 6 to 38 KDa. The effect of the ADMET polymerization temperature in the thermal properties of the copolymers was studied and their thermal degradation and flame retardant properties were evaluated. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5760–5771, 2009 相似文献
108.
A.-F. Maggio M. Lucas J.-L. Barascut J.-L. Imbach 《Journal of heterocyclic chemistry》1986,23(3):969-970
The synthesis of a tricyclic deoxynucleoside by reaction of β-substituted ethanols with an activated deoxyguanosine is described. Its formation is rationnalised by an O6-N1-transposition. 相似文献
109.
J. B. Natowitz S. Leray R. Lucas C. Ngô E. Tomasi C. Volant 《Zeitschrift für Physik A Hadrons and Nuclei》1986,325(4):467-474
A simple formula based on leading particle models of nucleon-nucleon collisions is used to evaluate the average momentum transfer in central heavy ion collisions at energies from 20 to 150 MeV/u. This formula, which reproduces a number of the features of the observed systematics, offers a straightforward explanation for the approximate universality of fractional linear momentum transfer as a function of velocity, the dependence of fractional momentum transfer on target mass and the greater fractional momentum transfer of the proton as compared to heavy ion projectiles. 相似文献
110.
M. -G. Porquet Ts. Venkova A. Astier I. Deloncle A. Prévost F. Azaiez A. Buta D. Curien O. Dorvaux G. Duchêne B. J. P. Gall F. Khalfallah I. Piqueras M. Rousseau M. Meyer N. Redon O. Stézowski R. Lucas A. Bogachev 《The European Physical Journal A - Hadrons and Nuclei》2006,28(2):153-159
The 87Kr nucleus has been produced as fission fragment in the fusion reaction 18O + 208Pb at 85MeV bombarding energy and studied with the Euroball IV array. High-spin states of this neutron-rich isotope have been
identified for the first time. Its level scheme has been obtained up to 6.3MeV excitation energy and spin I ∼ 23/2ℏ. Its structure is interpreted by analogy with those of the heavier isotones. The proposed configurations involve
both proton and neutron excitations from several sub-shells located close to the Fermi levels, particularly νd5/2, πp3/2f5/2 and πg9/2. Moreover, a revised spin value of 5/2- for the 87Br ground state is proposed. 相似文献