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391.
A study of the long-range, local and electronic structure of Nd0.5Sr0.5MnO3 films of varying thickness between 500 and 2000 Å has been performed. Local structure measurements at the Sr K-edge reveal a reduction of the Mn-O-Mn bond angles in films below 1000 Å. Spin-polarized measurements reveal splitting of the Mn 3d eg state in the strained region of the films and are consistent with a two-layer model for thick films with a relaxed undistorted layer on top of a strained structurally distorted layer near the substrate. 相似文献
392.
Thomas D. Panning Layne T. Watson Nicholas A. Allen Katherine C. Chen Clifford A. Shaffer John J. Tyson 《Journal of Global Optimization》2008,40(4):719-738
Two parallel deterministic direct search algorithms are combined to find improved parameters for a system of differential
equations designed to simulate the cell cycle of budding yeast. Comparing the model simulation results to experimental data
is difficult because most of the experimental data is qualitative rather than quantitative. An algorithm to convert simulation
results to mutant phenotypes is presented. Vectors of the 143 parameters defining the differential equation model are rated
by a discontinuous objective function. Parallel results on a 2200 processor supercomputer are presented for a global optimization
algorithm, DIRECT, a local optimization algorithm, MADS, and a hybrid of the two. 相似文献
393.
394.
Arpesella C Back HO Balata M Bellini G Benziger J Bonetti S Brigatti A Caccianiga B Cadonati L Calaprice F Carraro C Cecchet G Chavarria A Chen M Dalnoki-Veress F D'Angelo D de Bari A de Bellefon A de Kerret H Derbin A Deutsch M di Credico A di Pietro G Eisenstein R Elisei F Etenko A Fernholz R Fomenko K Ford R Franco D Freudiger B Galbiati C Gatti F Gazzana S Giammarchi M Giugni D Goeger-Neff M Goldbrunner T Goretti A Grieb C Hagner C Hampel W Harding E Hardy S Hartman FX Hertrich T Heusser G 《Physical review letters》2008,101(9):091302
We report the direct measurement of the 7Be solar neutrino signal rate performed with the Borexino detector at the Laboratori Nazionali del Gran Sasso. The interaction rate of the 0.862 MeV 7Be neutrinos is 49+/-3stat+/-4syst counts/(day.100 ton). The hypothesis of no oscillation for 7Be solar neutrinos is inconsistent with our measurement at the 4sigma C.L. Our result is the first direct measurement of the survival probability for solar nu(e) in the transition region between matter-enhanced and vacuum-driven oscillations. The measurement improves the experimental determination of the flux of 7Be, pp, and CNO solar nu(e), and the limit on the effective neutrino magnetic moment using solar neutrinos. 相似文献
395.
Back BB Baker MD Barton DS Betts RR Bindel R Budzanowski A Busza W Carroll A Decowski MP Garcia E George N Gulbrandsen K Gushue S Halliwell C Hamblen J Henderson C Hofman D Hollis RS Hołyński R Holzman B Iordanova A Johnson E Kane J Katzy J Khan N Kucewicz W Kulinich P Kuo CM Lin WT Manly S McLeod D Michałowski J Mignerey A Nouicer R Olszewski A Pak R Park IC Pernegger H Reed C Remsberg LP Reuter M Roland C Roland G Rosenberg L Sagerer J Sarin P Sawicki P Skulski W Steadman SG Steinberg P 《Physical review letters》2002,89(22):222301
This paper describes the measurement of collective flow for charged particles in Au+Au collisions at sqrt[s(NN)]=130 GeV using the PHOBOS detector at the Relativistic Heavy Ion Collider (RHIC). The measured azimuthal hit anisotropy is presented over a wide range of pseudorapidity (-5.0相似文献
396.
Hsiang-Chen Chui Ming-Sheng Ko Yi-Wei Liu Tyson Lin Jow-Tsong Shy Sen-Yen Shaw Rostislav V. Roussev Martin M. Fejer 《Optics and Lasers in Engineering》2006,44(5):479-485
A 197.2 THz (1520.2 nm) ITU-T grid distributed feedback (DFB) diode laser is frequency stabilized at 197.198 THz by 1ocking its second harmonic (SH) signal on the rubidium 5S1/2→7S1/2 two-photon transition at 394.396 THz (760.1 nm). With 100 mW from the DFB diode laser and amplifying by an erbium-doped fiber amplifier, we obtain an SH power of 15 mW using a periodically poled lithium niobate (PPLN) waveguide frequency doubler. The stability was 2×10−11 (10 s), corresponding to a frequency variation of 4 kHz at 1520.2 nm. Our scheme provides a compact and high performance frequency reference in the communication band. 相似文献
397.
The selectivity of immobilised 8-hydroxyquinoline for lead is shown to be improved by the use of masking agents during pre-concentration, prior to determination by flame atomic absorption spectrometry. Interference by iron, copper, aluminium and zinc is suppressed by including triethanolamine, thiourea, fluoride, acetylacetone or cyanide in the buffer as masking agents. Species such as iron or copper can completely prevent the pre-concentration of lead. This is shown to be overcome by using a buffer consisting of 0.2 M boric acid, 2% triethanolamine, 2% thiourea and 2% acetylacetone, even when the interfering species is in a 200-fold excess over lead. Recoveries from tap water samples, to which various amounts of lead had been added, ranged from 94 to 108%. Results of analyses of tap water samples using this method were in good agreement with those obtained by electrothermal atomic absorption spectrometry. 相似文献
398.
Efficient multi-keV X-ray sources from Ti-doped aerogel targets 总被引:1,自引:0,他引:1
Fournier KB Constantin C Poco J Miller MC Back CA Suter LJ Satcher J Davis J Grun J 《Physical review letters》2004,92(16):165005
We have measured the production of hnu approximately 4.7 keV x rays from low-density Ti-doped aerogel (rho approximately 3 mg/cc) targets at the OMEGA laser facility (University of Rochester), with the goal of maximizing x-ray output. Forty OMEGA beams (lambda(L)=0.351 microm) illuminated the two cylindrical faces of the target with a total power that ranged from 7 to 14 TW. The laser fully ionizes the target (n(e)/n(crit)=0.1), and a laser-bleaching wave excites, supersonically, the high-Z emitter ions in the sample. Ti K-shell x-ray emission was spectrally resolved with a two-channel crystal spectrometer and also with a set of filtered aluminum x-ray diodes; both instruments provide absolute measurement of the multi-keV x-ray emission. We find between 40 and 260 J of output with 4.67=hnu=5.0 keV. 相似文献
399.
The thermodynamic redox potentials of films of constitutional isomers of iron-sulfur cluster core dendrimers were measured and compared. It was determined that the primary structure of the dendrimer influences its reduction potential. Dendrimers containing so-called backfolded linkages were more difficult to reduce than their extended analogues. This behavior is rationalized by suggesting that the backfolded isomers pack more tightly around the iron-sulfur cluster, creating a more hydrophobic local microenvironment. Also, all of these molecules are easier to reduce in the film than in dimethyl formamide solution. The variation in redox potential between film and solution environment was compared to that of dendrimers of differing generations and correlated with the amount of hydrophobic dendron surrounding the cluster. 相似文献
400.
Buess M Höllinger R Haug T Perzlmaier K Krey U Pescia D Scheinfein MR Weiss D Back CH 《Physical review letters》2004,93(7):077207
Thin-circular lithographically defined magnetic elements with a spin vortex configuration are excited with a short perpendicular magnetic field pulse. We report the first images of excited magnetic eigenmodes up to third order, obtained by means of a phase sensitive Fourier transform imaging technique. Both axially symmetric and symmetry breaking azimuthal eigenmodes are observed. We observe strong oscillations of the magnetization in the central part of the magnetic elements. The experimental data are in good agreement with micromagnetic simulations. 相似文献