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901.
902.
L. Landström D. Brodoceanu K. Piglmayer D. Bäuerle 《Applied Physics A: Materials Science & Processing》2006,84(4):373-377
Extraordinary optical transmission through metal-coated close-packed monolayers has been observed. The monolayers consist of silica (a-SiO2) or polystyrene microspheres that form two-dimensional close-packed lattices by self-assembly. Metal layers of Ag, Au and Ni with different thicknesses (larger than the skin depth) were evaporated onto such lattices by means of standard techniques. The optical transmission spectra investigated between 300 and 2500 nm show pronounced peaks that scale with the diameter and the optical properties of the composite slabs. The enhanced transmission observed is most likely mediated via plasmons. PACS 78.66.-w; 81.16.Dn; 82.70.Dd 相似文献
903.
R. Ortega D. d'Enterria G. Martınez D. Baiborodin H. Delagrange J. Dıaz F. Fernández H. Löhner T. Matulewicz R. W. Ostendorf S. Schadmand Y. Schutz P. Tlusty R. Turrisi V. Wagner H. W. Wilschut N. Yahlali 《The European Physical Journal A - Hadrons and Nuclei》2006,28(2):161-171
Measured hard-photon multiplicities from second-chance nucleon-nucleon collisions are used in combination with a kinetic thermal
model to estimate the breakup times of excited nuclear systems produced in nucleus-nucleus reactions at intermediate energies.
The obtained nuclear breakup time for the 129Xe + natSn reaction at 50 A MeV is Δτ ≈ 100-300 fm/c for all reaction centralities. The lifetime of the radiating sources produced in seven other different heavy-ion reactions
studied by the TAPS experiment is consistent with Δτ ≈ 100 fm/c, such relatively long thermal photon emission times do not seemingly support the interpretation of nuclear breakup as due
to a fast spinodal process for the heavy nuclear systems studied. 相似文献
904.
Sofia Quinodoz Michael A. Thomas Jörn Dunkel Eva-Maria Schötz 《Journal of statistical physics》2011,142(6):1324-1336
The trade-off between traits in life-history strategies has been widely studied for sexual and parthenogenetic organisms,
but relatively little is known about the reproduction strategies of asexual animals. Here, we investigate clonal reproduction
in the freshwater planarian Schmidtea mediterranea, an important model organism for regeneration and stem cell research. We find that these flatworms adopt a randomized reproduction
strategy that comprises both asymmetric binary fission and fragmentation (generation of multiple offspring during a reproduction
cycle). Fragmentation in planarians has primarily been regarded as an abnormal behavior in the past; using a large-scale experimental
approach, we now show that about one third of the reproduction events in S. mediterranea are fragmentations, implying that fragmentation is part of their normal reproductive behavior. Our analysis further suggests
that certain characteristic aspects of the reproduction statistics can be explained in terms of a maximum relative entropy
principle. 相似文献
905.
We discuss the conditions for additional supersymmetry and twisted super-symmetry in N = (2, 2) supersymmetric nonlinear sigma models described by one left and one right semi-chiral superfield and carrying a pair of non-commuting complex structures. Focus is on linear non-manifest transformations of these fields that have an algebra that closes off-shell. We find that additional linear supersymmetry has no interesting solution, whereas additional linear twisted supersymmetry has solutions with interesting geometrical properties. We solve the conditions for invariance of the action and show that these solutions correspond to a bi-hermitian metric of signature (2, 2) and a pseudo-hyperkähler geometry of the target space. 相似文献
906.
Papadakis CM Darko C Di Z Troll K Metwalli E Timmann A Reiter G Förster S 《The European physical journal. E, Soft matter》2011,34(1):7-8
We have found very slow crystallization in thin films of cylinder-forming poly(isoprene-b -ethyleneoxide) (P(I-b -EO)) diblock copolymers with PEO being the minority block. The film was crystallized at room temperature after melting at
62 °C . Imaging methods were combined with X-ray reflectometry and grazing-incidence small-angle X-ray scattering and diffraction.
Initially, hexagonally packed, amorphous PEO cylinders lie in the film plane. After 148 days, crystallized, finger-like terraces
were observed over the entire film surface. The terrace height is 20% higher than the repeat distance in the as-prepared film.
Thus, at the film surface, the cylinders have been destroyed by crystalline lamellae lying in the film plane. The PEO chain
stems are perpendicular to the substrate surface and are once-folded and fully interdigitated. The substrate-near layers still
consist of the hexagonally packed, amorphous PEO cylinders within the PI matrix. 相似文献
907.
Momentum resolved inverse photoemission spectra from Ni(0 0 1) are presented. The experimental dispersion of direct transitions are in good agreement with predictions from a recent band structure calculation and with results from spectra calculated on the basis of a one step theory. Comparison of the present data with earlier normal incidence spectra collected with a different experimental setup reveals a very strong polarization effect. 相似文献
908.
We generalize our recent approach to the reconstruction of phase dynamics of coupled oscillators from data [B. Kralemann et al., Phys. Rev. E 77, 066205 (2008)] to cover the case of small networks of coupled periodic units. Starting from a multivariate time series, we first reconstruct genuine phases and then obtain the coupling functions in terms of these phases. Partial norms of these coupling functions quantify directed coupling between oscillators. We illustrate the method by different network motifs for three coupled oscillators and for random networks of five and nine units. We also discuss nonlinear effects in coupling. 相似文献
909.
Ehrke H Tobey RI Wall S Cavill SA Först M Khanna V Garl T Stojanovic N Prabhakaran D Boothroyd AT Gensch M Mirone A Reutler P Revcolevschi A Dhesi SS Cavalleri A 《Physical review letters》2011,106(21):217401
We used ultrafast resonant soft x-ray diffraction to probe the picosecond dynamics of spin and orbital order in La(0.5)Sr(1.5)MnO(4) after photoexcitation with a femtosecond pulse of 1.5 eV radiation. Complete melting of antiferromagnetic spin order is evidenced by the disappearance of a (1/4,1/4,1/2) diffraction peak. On the other hand, the (1/4,1/4,0) diffraction peak, reflecting orbital order, is only partially reduced. We interpret the results as evidence of destabilization in the short-range exchange pattern with no significant relaxation of the long-range Jahn-Teller distortions. Cluster calculations are used to analyze different possible magnetically ordered states in the long-lived metastable phase. Nonthermal coupling between light and magnetism emerges as a primary aspect of photoinduced phase transitions in manganites. 相似文献
910.
Chatrchyan S Khachatryan V Sirunyan AM Tumasyan A Adam W Bergauer T Dragicevic M Erö J Fabjan C Friedl M Frühwirth R Ghete VM Hammer J Hänsel S Hartl C Hoch M Hörmann N Hrubec J Jeitler M Kasieczka G Kiesenhofer W Krammer M Liko D Mikulec I Pernicka M Rohringer H Schöfbeck R Strauss J Teischinger F Wagner P Waltenberger W Walzel G Widl E Wulz CE Mossolov V Shumeiko N Suarez Gonzalez J Benucci L De Wolf EA Janssen X Maes T Mucibello L Ochesanu S Roland B Rougny R Selvaggi M Van Haevermaet H 《Physical review letters》2011,106(21):212301
A search for Z bosons in the μ(+)μ(-) decay channel has been performed in PbPb collisions at √S(NN)=2.76 TeV with the CMS detector at the LHC, in a 7.2 μb(-1) data sample. The number of opposite-sign muon pairs observed in the 60-120 GeV/c(2) invariant mass range is 39, corresponding to a yield per unit of rapidity (y) and per minimum bias event of [33.8±5.5(stat)±4.4(syst)]×10(-8), in the |y|<2.0 range. Rapidity, transverse momentum, and centrality dependencies are also measured. The results agree with next-to-leading order QCD calculations, scaled by the number of incoherent nucleon-nucleon collisions. 相似文献